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Integrated analysis of lncRNA/circRNA–miRNA–mRNA in the proliferative phase of liver regeneration in mice with liver fibrosis

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Background Non-coding RNAs play important roles in liver regeneration; however, their functions and mechanisms of action in the regeneration of fibrotic liver have not been elucidated. We aimed to clarify the expression patterns and regulatory functions of lncRNAs, circRNAs, miRNAs, and mRNAs in the proliferative phase of fibrotic liver regeneration. Methods Based on a mouse model of liver fibrosis with 70% hepatectomy, whole-transcriptome profiling was performed using high-throughput sequencing on samples collected at 0, 12, 24, 48, and 72 h after hepatectomy. Hub genes were selected by weighted gene co-expression network analysis and subjected to enrichment analysis. Integrated analysis was performed to reveal the interactions of differentially expressed (DE) lncRNAs, circRNAs, miRNAs, and mRNAs, and to construct lncRNA–mRNA cis- and trans-regulatory networks and lncRNA/circRNA–miRNA–mRNA ceRNA regulatory networks. Real-Time quantitative PCR was used to validate part of the ceRNA network. Results A total of 1,329 lncRNAs, 48 circRNAs, 167 miRNAs, and 6,458 mRNAs were differentially expressed, including 812 hub genes. Based on these DE RNAs, we examined several mechanisms of ncRNA regulatory networks, including lncRNA cis and trans interactions, circRNA parental genes, and ceRNA pathways. We constructed a cis-regulatory core network consisting of 64 lncRNA–mRNA pairs (53 DE lncRNAs and 58 hub genes), a trans-regulatory core network consisting of 103 lncRNA–mRNA pairs (18 DE lncRNAs and 85 hub genes), a lncRNA–miRNA–mRNA ceRNA core regulatory network (20 DE lncRNAs, 12 DE miRNAs, and 33 mRNAs), and a circRNA–miRNA–mRNA ceRNA core regulatory network (5 DE circRNAs, 5 DE miRNAs, and 39 mRNAs). Conclusions These results reveal the expression patterns of lncRNAs, circRNAs, miRNAs, and mRNAs in the proliferative phase of fibrotic liver regeneration, as well as core regulatory networks of mRNAs and non-coding RNAs underlying liver regeneration. The findings provide insights into molecular mechanisms that may be useful in developing new therapeutic approaches to ameliorate diseases that are characterized by liver fibrosis, which would be beneficial for the prevention of liver failure and treatment of liver cancer.
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Wang et al. BMC Genomics (2023) 24:417
https://doi.org/10.1186/s12864-023-09478-z BMC Genomics
*Correspondence:
Xiaoming Dai
fydaixiaoming@126.com
Zhu Zhu
zhuzhu027@gmail.com
Full list of author information is available at the end of the article
Abstract
Background Non-coding RNAs play important roles in liver regeneration; however, their functions and mechanisms
of action in the regeneration of fibrotic liver have not been elucidated. We aimed to clarify the expression patterns
and regulatory functions of lncRNAs, circRNAs, miRNAs, and mRNAs in the proliferative phase of fibrotic liver
regeneration.
Methods Based on a mouse model of liver fibrosis with 70% hepatectomy, whole-transcriptome profiling was
performed using high-throughput sequencing on samples collected at 0, 12, 24, 48, and 72 h after hepatectomy.
Hub genes were selected by weighted gene co-expression network analysis and subjected to enrichment analysis.
Integrated analysis was performed to reveal the interactions of differentially expressed (DE) lncRNAs, circRNAs,
miRNAs, and mRNAs, and to construct lncRNA–mRNA cis- and trans-regulatory networks and lncRNA/circRNA–
miRNA–mRNA ceRNA regulatory networks. Real-Time quantitative PCR was used to validate part of the ceRNA
network.
Results A total of 1,329 lncRNAs, 48 circRNAs, 167 miRNAs, and 6,458 mRNAs were differentially expressed, including
812 hub genes. Based on these DE RNAs, we examined several mechanisms of ncRNA regulatory networks, including
lncRNA cis and trans interactions, circRNA parental genes, and ceRNA pathways. We constructed a cis-regulatory
core network consisting of 64 lncRNA–mRNA pairs (53 DE lncRNAs and 58 hub genes), a trans-regulatory core
network consisting of 103 lncRNA–mRNA pairs (18 DE lncRNAs and 85 hub genes), a lncRNA–miRNA–mRNA ceRNA
core regulatory network (20 DE lncRNAs, 12 DE miRNAs, and 33 mRNAs), and a circRNA–miRNA–mRNA ceRNA core
regulatory network (5 DE circRNAs, 5 DE miRNAs, and 39 mRNAs).
Conclusions These results reveal the expression patterns of lncRNAs, circRNAs, miRNAs, and mRNAs in the
proliferative phase of fibrotic liver regeneration, as well as core regulatory networks of mRNAs and non-coding
RNAs underlying liver regeneration. The findings provide insights into molecular mechanisms that may be useful in
Integrated analysis of lncRNA/circRNA–
miRNA–mRNA in the proliferative phase
of liver regeneration in mice with liver brosis
Qian Wang1, Zhangtao Long2, Fengfeng Zhu2, Huajian Li2, Zhiqiang Xiang2, Hao Liang2, Yachen Wu2, Xiaoming Dai2*
and Zhu Zhu2,3*
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Page 2 of 12
Wang et al. BMC Genomics (2023) 24:417
Introduction
Liver brosis is a pathophysiological process character-
ized by abnormal proliferation of connective tissue in
the liver, which results from chronic liver injury caused
by viral hepatitis, alcoholic steatohepatitis, or non-alco-
holic steatohepatitis [1]. Chronic liver injury triggers an
inammatory response, leading to the death of hepa-
tocytes and the accumulation of extracellular matrix,
resulting in the formation of scar tissue that underlies
liver brosis [24]. Studies have shown that liver brosis
can aect the reserve function and regenerative capac-
ity of the liver [57]. Furthermore, liver brosis often
progresses to liver cirrhosis, liver failure, and liver can-
cer, seriously aecting the prognosis and life quality of
patients [8].
e liver is one of the most important organs and has
a variety of complex functions such as detoxication,
metabolism, biosynthesis, and immunity [9]. Addition-
ally, the liver exhibits remarkable regenerative capabili-
ties: in rodents with 70% hepatectomy, the residual liver
rapidly restored its original size and regained its physi-
ological functions [10, 11]. Liver regeneration is typically
divided into three phases: the priming phase (0–6h), the
proliferative phase (12–72 h), and the terminal phase
(96–168h) [12]. e proliferative phase, in which qui-
escent (G0 phase) hepatocytes enter the cell cycle (G1/S
phase) and initiate proliferation, plays a key role in liver
regeneration [13]. Liver regeneration involves a variety of
cells (liver parenchymal and mesenchymal cells) and mol-
ecules (cytokines, growth factors, and metabolites) and is
triggered by stimuli such as surgery and injury [1416].
Non-coding RNAs (ncRNAs) are RNA molecules
that are not translated into proteins and that mainly
include microRNAs (miRNAs), long non-coding RNAs
(lncRNAs), and circular RNAs (circRNAs). miRNAs are
single-stranded RNA molecules of 21–25 nucleotides
in length that can inhibit the expression of messenger
RNAs (mRNAs) by specically binding to the 3-untrans-
lated region (3-UTR) [17]. e competing endogenous
RNA (ceRNA) hypothesis proposes an RNA interaction
mechanism by which gene expression can be regulated
by non-coding RNAs, such as lncRNAs and circRNAs,
through competitively binding to miRNAs [12]. lncRNAs
are RNA molecules of 200–100,000 nucleotides that
regulate gene expression through cis-regulation, trans-
regulation, and ceRNAs [18, 19]. Additionally, circRNAs
are closed-loop RNA molecules capable of regulating
gene expression through mechanisms such as regulation
of parental genes, ceRNA interactions, and interactions
with RNA-binding proteins [20, 21]. Studies have dem-
onstrated that ncRNAs, including miRNAs, lncRNAs,
and circRNAs, are crucial regulators of liver regeneration
[2224]. However, their functions in brotic liver regen-
eration are poorly understood.
In this study, a mouse model of liver brosis with 70%
hepatectomy was established to identify the key mRNAs
and establish lncRNA/circRNA–miRNA–mRNA regu-
latory networks across the proliferative phase of brotic
liver regeneration. Whole-transcriptome proling was
performed using high-throughput sequencing. Hub
genes were selected by weighted gene co-expression net-
work analysis (WGCNA) and subjected to enrichment
analysis, and dierentially expressed (DE) lncRNAs, cir-
cRNAs, miRNAs, and mRNAs were subjected to corre-
lation analysis. ese ndings provide new insights into
the mechanisms of liver regeneration that could help
identify biomarkers and therapeutic targets to ameliorate
liver brosis.
Materials and methods
Establishment of a mouse model of liver brosis with 70%
hepatectomy
Healthy adult male C57BL/6J mice (8 weeks of age and
weighing 24–26 g) were purchased from Hunan SJA
Laboratory Animal (Changsha, China). e mice were
housed at the Experimental Animal Center of Univer-
sity of South China (20–25°C, 50–55% humidity, 12h
light/12h dark, standard chow, and free access to water
and food). Carbon tetrachloride in olive oil was injected
intraperitoneally at 5 ml/kg twice a week for 8 weeks.
irty mice underwent 70% hepatectomy at week 9 by
excision of the left lateral and middle lobes after intra-
peritoneal injection of l% pentobarbital sodium at 50mg/
kg [25]. e liver samples were xed in 4% paraformalde-
hyde for histopathological examination using hematoxy-
lin and eosin and Masson staining. To assess hepatocyte
proliferation, the sections were further processed for
immunohistochemistry with anti-Ki-67 antibody (1:100,
Abcam, United Kingdom). e right lateral lobes were
collected at 0, 12, 24, 48, and 72 h after hepatectomy
with six mice in each group. e samples were stored
at 80°C within 30min following collection. All animal
experiments were performed in accordance with inter-
nationally recognized guidelines for the care and use of
laboratory animals and were approved by the Committee
for the Care and Use of Experimental Animals of Univer-
sity of South China.
developing new therapeutic approaches to ameliorate diseases that are characterized by liver fibrosis, which would
be beneficial for the prevention of liver failure and treatment of liver cancer.
Keywords Liver fibrosis, Liver regeneration, LncRNA, CircRNA, MiRNA, MRNA
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Page 3 of 12
Wang et al. BMC Genomics (2023) 24:417
High-throughput RNA sequencing
Liver samples of mice with liver brosis were sent to
Novogene (Beijing, China) for high-throughput sequenc-
ing. Strand-specic libraries were generated using the
NEBNext® UltraTM RNA Library Prep Kit for Illumina®
(NEB, USA). Total RNA was extracted, and the purity,
integrity and concentration were evaluated by 1% agarose
gel electrophoresis and OD260/280 and OD260/230 measure-
ment (NanoPhotometer® spectrophotometer; Implen,
Germany). e Agilent 2100 bioanalyzer (Agilent Tech-
nologies, USA) was used to further verify the RNA integ-
rity and quality. Total RNA (1 µg) of each sample was
used for transcriptome sequencing, and double-stranded
cDNA was synthesized using fragmented rRNA-free
RNA as a template. e puried double-stranded cDNA
was subjected to end repair, poly-A addition, and adap-
tor ligation. Resulting cDNA fragments of 350–400 bp
were selected using AMPure XP beads (Beckman Coul-
ter, USA), and the second cDNA strand was degraded.
Finally, PCR amplication was performed to construct
the library, and the eective concentration (> 2 nM) was
measured by real-time quantitative PCR (RT-qPCR) to
ensure the quality.
e construction of miRNA libraries followed a simi-
lar, but slightly dierent procedure. e small RNA
libraries were generated using the NEBNext® Multiplex
Small RNA Library Prep Set for Illumina® (NEB, USA).
Briey, 2µg of total RNA from each sample was used to
prepare the miRNA libraries. e puried miRNA was
ligated with adaptors at the 3ˊ and 5ˊ ends, and the rst
cDNA strand was synthesized using reverse transcription
primers. After PCR amplication of the cDNA library,
the products were puried, and 140–160bp DNA frag-
ments were recovered. Finally, the quality of the library
was assessed using an Agilent 2100 bioanalyzer (eective
library concentration > 2 nM).
Quality-veried libraries were used for sequencing
with PE150 on an Illumina NovaSeq 6000 platform (Illu-
mina, USA) based on the eective concentration of the
library and the requirements of data output. Raw reads
were ltered using Perl 6 to remove reads with adaptors,
undetermined bases at a frequency of > 0.002, or > 50%
low-quality bases at one end, in order to ensure the qual-
ity and reliability of the sequencing data. e error rates
(Q20 and Q30) and GC content were determined using
Illumina Casava (v1.8) to obtain clean reads for subse-
quent analysis (Q20 > 95%, Q30 > 90%, GC = 48–52%).
e reference genome (GRCm39) and gene model
annotation les of lncRNAs and mRNAs were down-
loaded from the genome website (https://www.ncbi.nlm.
nih.gov/). Clean reads were aligned against the reference
genome using hisat (v2.0.5), and the mapped read count
was calculated using StringTie (v1.3.3). circRNAs were
identied by nd_circ (v1.0) [26] and CIRI (v2.0.5) [27].
Clean reads were mapped to the reference sequences in
miRBase (v22.0) using Bowtie (v2.0.6) to identify known
miRNA sequences. e sQuantier.pl script in MirDeep2
was used to quantify miRNAs and obtain read counts.
Identication of dierentially expressed (DE) RNA genes
To quantify the gene expression levels, the read counts
were normalized using the transcripts per million
method. Violin plots were used to visualize the overall
distributions of gene expression levels. e heatmap R
package (v1.0.12) was used to generate heatmaps.
e lncRNAs, circRNAs, miRNAs, and mRNAs with
dierential expression in the 12h, 24, 48 and 72h groups
relative to the 0h group were selected using the edge
package (v3.38.4) in R (v4.1.0) [28]. Read counts were
normalized using trimmed mean of M-values, and DE
genes were selected based on the negative binomial dis-
tribution test. For lncRNAs, miRNAs, and mRNAs, the
selection criteria were |log2 (Fold Change)| > log2 (1.5)
and p < 0.05 for DE genes; log2 (Fold Change) > log2
(1.5) for signicantly up-regulated genes; and log2 (Fold
Change) < log2 (1.5) for signicantly down-regulated
genes. For circRNAs, the selection criteria were |log2
(Fold Change)| > log2 (1) and p < 0.05 for DE genes; log2
(Fold Change) > log2 (1) for signicantly up-regulated
genes; and log2 (Fold Change) < log2 (1) for signicantly
down-regulated genes. Finally, the ggplot2 R package
(v3.0.4) was used to generate volcano plots.
Weighted gene co-expression network analysis
A weighted gene co-expression network was created
using the WGCNA R package (v1.71). e read count of
DE mRNA was normalized using the fragments per kilo-
base million method for clustering. A soft threshold was
determined after removing outliers. An adjacency matrix
was constructed and transformed into a topological over-
lap matrix. DE mRNAs were clustered and divided into
modules using the dynamic tree cutting algorithm. Mod-
ule–phase correlations were calculated, and the mod-
ules with the highest correlations were selected as key
modules.
Identication and functional enrichment of hub genes
e gene signicance (GS, indicative of the correla-
tion between the gene expression pattern and the trait/
regeneration phase), and the module membership (MM,
indicative of the correlation between the gene expres-
sion pattern and module eigengene) were calculated. e
correlations between GS and MM were analyzed for key
modules and presented in scatter plots. e mRNAs with
|MM| >0.8 and |GS| >0.5 in key modules were selected as
hub genes for further analysis.
e R package ClusterProlter (v4.4.4) was used for
Gene Ontology [29] and Kyoto Encyclopedia of Genes
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Wang et al. BMC Genomics (2023) 24:417
and Genomes [3033] enrichment analysis of the hub
genes. GO enrichment analysis included biological pro-
cesses, cellular components, and molecular functions,
but only biological processes are shown in the present
study. Gene annotation was performed using the org.
Mm.eg.db R package (v3.15.0). e p-values in GO/
KEGG enrichment analysis were calculated based on
a hypergeometric distribution and corrected using the
false discovery rate (FDR), and p < 0.05 indicated signi-
cant enrichment. Finally, the ggplot2 R package (v3.0.4)
was used to visualize the top ten terms/pathways based
on the p-value.
lncRNA/circRNA–mRNA regulatory networks and
functional enrichment
Pearson correlation coecients (r) between DE lncRNAs
or DE circRNAs and their potential regulatory targets
were calculated using the Hmisc R package (v4.7-1). DE
mRNAs located within 100kb upstream and downstream
of DE lncRNAs on the same chromosome were selected
as potential cis-regulatory targets. e lncRNA–mRNA
and circRNA-mRNA pairs with |r| >0.6 were selected
as cis-regulatory pairs, and lncRNA–mRNA pairs with
|r| >0.9 were selected as trans-regulatory pairs. e
mRNAs were subjected to GO/KEGG enrichment analy-
sis, and the top ten terms/pathways for the cis-regulatory
and trans-regulatory pairs were visualized based on the
p-values. e regulatory pairs containing hub genes were
selected as key pairs, and corresponding lncRNA/cir-
cRNA–mRNA cis-regulatory and trans-regulatory core
networks were constructed.
Construction of ceRNA core networks
Starbase [34] and miRanda (v3.3a) were used to predict
the potential targets of DE lncRNA–DE miRNA and hub
gene–DE miRNA pairs; miRanda (v3.3a) was used to
predict the potential targets of DE circRNA–DE miRNA
pairs. lncRNA/circRNA–miRNA–mRNA (hub gene)
ceRNA regulatory networks were constructed accord-
ing to the following criteria: (1) one or more DE miRNA
binding sites shared by DE lncRNAs/DE circRNAs and
hub genes; (2) positive correlations between the expres-
sion of DE lncRNAs/DE circRNAs and hub genes sharing
the DE miRNA binding sites; and (3) negative correla-
tions between the expression of DE miRNAs, target DE
lncRNAs and hub genes. lncRNA–miRNA–mRNA and
circRNA–miRNA–mRNA ceRNA core regulatory net-
works were constructed based on the Spearman correla-
tion coecient (ρ < 0.05).
Real-time quantitative PCR
One lncRNA–miRNA–mRNA pathway and one cir-
cRNA–miRNA–mRNA pathway were randomly selected
from the ceRNA regulatory networks, and the mRNAs in
both pathways were detected by RT-qPCR for validation.
RNA was extracted using the TRIzol method, and cDNA
was reverse transcribed using total mRNA as a template.
PCR was performed using SYBR Green PCR Master Mix
and specic primers (Supplementary Table S1). Relative
gene expression was calculated using the 2ΔΔCt method.
e read counts from high-throughput RNA sequenc-
ing were normalized using the transcripts per million
method to obtain the relative expression of RNA for
comparison with the RT-qPCR results. One-way analysis
of variance was used for comparisons between groups.
e Bonferroni method was used to adjust the p-value,
and the signicant level set at P < 0.05. e expression
patterns of ncRNAs and mRNAs in the two pathways
were assessed to determine whether they conformed to
the ceRNA hypothesis.
Results
Analysis of lncRNAs, circRNAs, miRNAs, and mRNAs that
are dierentially expressed during liver regeneration
To identify regulatory networks that underlie the prolif-
erative phase of brotic liver regeneration, we established
a mouse model of liver brosis with 70% hepatectomy.
Subsequent examination revealed that all mice exhibited
the pathological features of liver brosis (Supplementary
Fig.1). Total RNA was extracted from liver samples at
0, 12, 24, 48, and 72h for high-throughput sequencing
and quantitative analysis. After excluding genes with no
expression in 25% of samples, 3,706 lncRNAs, 185 cir-
cRNAs, 563 miRNAs, and 14,999 mRNAs were identied
(Supplementary Table S2), for which the expression pat-
terns are presented as violin plots (Fig.1A–D) and heat-
maps (Fig.1E–H).
Compared with the 0h group, the proliferation phase
groups (12–72 h) showed the following dierentially
expressed genes: 661 lncRNAs (352 up-regulated and
309 down-regulated), 19 circRNAs (9 and 10), 52 miR-
NAs (35 and 17), and 3,837 mRNAs (1,795 and 2,042) in
the 12h group; 667 lncRNAs (358 and 309), 19 circRNAs
(7 and 12), 78 miRNAs (65 and 13), and 3,664 mRNAs
(2,107 and 1,557) in the 24h group; 556 lncRNAs (283
and 273), 23 circRNAs (10 and 13), 56 miRNAs (39 and
17), and 3,498 mRNAs (1,978 and 1,520) in the 48 h
group; and 502 lncRNAs (274 and 228), 21 circRNAs
(9 and 12), 85 miRNAs (61 and 24), and 3,282 mRNAs
(1,982 and 1,300) in the 72h group (Supplementary Table
S3 and Supplementary Fig.2). e RNAs with dieren-
tial expression at any time point after 70% hepatectomy
were considered to be DE genes. Together, these included
1,329 lncRNAs, 48 circRNAs, 167 miRNAs, and 6,458
mRNAs (Fig. 1I–L), representing signicant changes in
the proliferative phase of liver regeneration in mice with
liver brosis.
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Page 5 of 12
Wang et al. BMC Genomics (2023) 24:417
Identication of key modules and hub genes associated
with liver regeneration
To further evaluate patterns of expression of the DE
RNAs during liver regeneration, we performed weighted
gene co-expression network analysis (WGCNA). After
normalizing the read counts of 6,458 DE mRNAs, the
outlier sample D4 was removed (Fig. 2A), and the soft
threshold was set to 11 (Fig. 2B). e remaining DE
mRNAs were then divided into 7 modules based on their
expression patterns. ese included MEturquoise (2,289
Fig. 2 Weighted gene co-expression network analysis of differentially expressed genes during liver regeneration. A Clustering of genes that were diffen-
tially expressed in the 12 h, 24 h, 48 h, and 72 h groups as compared to the 0 h group. B Soft threshold power for topological analysis. C Cluster dendro-
gram. D Hierarchical clustering heatmap. E-F Scatter plot of correlations between module membership (MM) and gene significance (GS) in MEturquoise
(E) and MEblue (F). G-H Clustering heatmaps of DE hub genes in MEturquoise (G) and MEblue (H)
Fig. 1 Expression patterns of lncRNAs, circRNAs, miRNAs, and mRNAs during liver regeneration in mice with liver fibrosis. A-D Violin plots of lncRNA
expression (A), circRNA expression (B), miRNA expression (C), and mRNA expression (D). E-H Hierarchical clustering heatmap of lncRNAs (E), circRNAs
(F), miRNAs (G), and mRNAs (H). I-L Venn diagram of lncRNAs (I), circRNAs (J), miRNAs (K), and mRNAs (L). Panels A-H show the expression profiles in 0 h,
12 h, 24 h, 48 h, and 72 h groups of mice; and panels I-L show differentially expressed (DE) RNAs in the proliferation phase (12–72 h) groups relative to
the 0 h group
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Wang et al. BMC Genomics (2023) 24:417
DE mRNAs), MEblue (930), MEgreen (548), MEgray
(542), MEred (448), MEyellow (788), and MEbrown (832)
(Fig.2C and Supplementary Table S4). e correlations
between co-expression modules and each regeneration
phase were determined (Fig.2D), and the MEturquoise
(0h) and the MEblue (12h) with the highest correlations
were selected as key modules.
Next, we sought to select and functionally enrich hub
genes within the key modules. Among 3,219 DE mRNAs
within the two key modules, scatter plots showed sig-
nicant correlations between gene signicance (GS) and
module membership (MM) (Fig. 2E–F). A total of 812
hub genes were selected. is included 556 hub genes
in MEturquoise, of which 79 were signicantly up-reg-
ulated and 477 were signicantly down-regulated at
0h (Fig.2G). Additionally, 256 hub genes in MEblue, of
which 238 were signicantly up-regulated and 18 were
signicantly down-regulated at 12h (Fig.2H).
Functional enrichment of hub genes associated with liver
regeneration
To determine the function of the hub genes in ME tur-
quoise and MEblue, we performed GO and KEGG
enrichment analyses. For GO analysis, the up-regulated
hub genes in MEturquoise were mainly associated with
regulation of cell growth, extracellular matrix organiza-
tion, and extracellular structure organization (Fig. 3A);
and the down-regulated hub genes were primarily asso-
ciated with fatty acid metabolic process, small molecule
catabolic process, and cellular amino acid metabolic
process (Fig. 3B). For KEGG analysis, the up-regulated
hub genes in MEturquoise showed no signicant KEGG
enrichment, and the down-regulated hub genes were
enriched in valine, leucine and isoleucine degradation,
steroid hormone biosynthesis, and pentose and glucuro-
nide interconversions (Fig.3C).
For MEblue, GO enrichment analysis indicate that
the up-regulated hub genes were mainly associated with
response to endoplasmic reticulum stress, Golgi vesicle
transport, and endoplasmic reticulum to Golgi vesicle-
mediated transport (Fig. 3D). e down-regulated hub
Fig. 3 Pathway analysis of hub genes. A–C GO/KEGG enrichment analysis of hub genes in MEturquoise. A GO enrichment analysis of up-regulated hub
genes. B GO enrichment analysis of down-regulated hub genes. C KEGG enrichment analysis of down-regulated hub genes. D–F GO/KEGG enrichment
analysis of hub genes in MEblue. D GO enrichment analysis of up-regulated hub genes. E GO enrichment analysis of down-regulated hub genes. F KEGG
enrichment analysis of up-regulated hub genes
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Wang et al. BMC Genomics (2023) 24:417
genes were primarily associated with cholesterol meta-
bolic process, sterol metabolic process, and secondary
alcohol metabolic process (Fig.3E). In KEGG enrichment
analysis, the up-regulated hub genes in MEblue were
enriched in protein export, amino sugar and nucleotide
sugar metabolism, and fructose and mannose metabo-
lism (Fig.3F), and the down-regulated hub genes showed
no signicant KEGG enrichment. ese pathways are
consistent with increased metabolic proliferative activity
and extracellular matrix remodeling, both of which are
associated with liver regeneration.
Identication and functional enrichment of core lncRNA/
circRNA–mRNA regulatory pairs associated with liver
regeneration
Given the key regulatory roles of lncRNAs and circRNAs
in ceRNA core networks, we evaluated the relationship
between lncRNAs/cirRNAs and mRNAs in terms of
cis- and trans-regulation potential. For lncRNAs, a total
of 175 DE lncRNAs and 190 DE mRNAs were identi-
ed, which formulated 212 potential cis-regulatory pairs
and 103 core trans-regulatory pairs. Based on hub genes
and their corresponding lncRNAs, 64 core cis-regulatory
pairs consisting of 53 DE lncRNAs and 58 hub genes were
identied (Fig. 4A). GO analysis revealed enrichment
in steroid metabolic process, ribonucleotide metabolic
process, and purine ribonucleotide metabolic process
(Supplementary Fig.3A); KEGG analysis showed enrich-
ment in steroid hormone biosynthesis, bile secretion,
and ascorbate and aldarate metabolism (Supplementary
Fig.3B). e 103 core trans-regulatory pairs consisted of
18 DE lncRNAs and 85 hub genes (Fig.4B). GO analysis
showed enrichment in small molecule catabolic process,
organic acid catabolic process, and steroid metabolic
process (Supplementary Fig.3C). KEGG analysis showed
enrichment in valine, leucine and isoleucine degradation,
fatty acid degradation, and tryptophan metabolism (Sup-
plementary Fig.3D).
For circRNAs, a total of 48 potential circRNA–parent
gene pairs were identied. GO analysis of parent genes
showed enrichment in small molecule catabolic process,
deoxyribonucleotide metabolic process, and nucleoside
metabolic process (Supplementary Fig.3E), while KEGG
analysis showed no signicantly enriched pathways.
Construction of ceRNA core networks
Next, we evaluated functional interactions based on the
set of 167 DE miRNAs that were dierentially expressed
in the 12h, 24h, 48h, or 72h group as compared to the
0h group. e Starbase database was used to predict the
targets of the DE miRNAs, which included 199,946 DE
miRNA–DE mRNA pairs and 1,456 DE miRNA–lncRNA
pairs (Supplementary Table S5). Additionally, miRanda
software was used to identify 29,237 DE miRNA–DE
mRNA pairs; 643,159 DE miRNA–lncRNA pairs; and
76,407 DE circRNA–DE miRNA pairs (Supplementary
Table S6). Based on the identied hub genes and the
ceRNA hypothesis, we constructed a lncRNA–miRNA–
mRNA ceRNA core regulatory network (Fig.5A), which
contained 20 lncRNAs, 12 miRNAs, and 33 hub genes.
We also constructed a circRNA–miRNA–mRNA ceRNA
core regulatory network (Fig.5B), which contained 5 cir-
cRNAs, 5 miRNAs, and 39 hub genes.
As verication of the ceRNA core networks, we ran-
domly selected RNAs in two pathways that are regu-
lated in response to liver regeneration for RT-qPCR
analysis. is includes lncRNA-Xist (NR_001463.3)/miR-
144-3P/mRNA-Aplp2, which was identied to be
downregulated, and circRNA-0000117/miRNA-
204-5p/mRNA-Derl1, which was identied to be upreg-
ulated in response to liver regeneration. eir relative
expression levels measured by RT-qPCR corresponded
with the results of high-throughput RNA sequencing,
and the change in the patterns of ncRNAs and mRNAs in
both pathways, which was most obvious at 12h but was
also showed a similar trend at other time points, con-
formed to the ceRNA hypothesis (Fig.6).
Discussion
Current transcriptome-wide studies on liver regeneration
have focused on healthy livers [25, 35]. is study pres-
ents the rst analysis of expression patterns and mecha-
nisms of action of lncRNAs, circRNAs, miRNAs, and
mRNAs in the regeneration of brotic liver, which may
provide new insights for the development of therapeutic
strategies for liver diseases. Liver brosis is a common
pathological process that occurs in a variety of chronic
liver diseases [36], and the injury stimuli and molecu-
lar signals are likely to be dierent for liver brosis and
regeneration. erefore, we reasoned that the transcrip-
tome-wide study of liver regeneration in the presence of
brosis may help to elucidate the molecular mechanisms
underlying curative processes in the disease and provide
new targets for preclinical investigations.
In this study, we employed WGCNA, a systems biology
approach for describing the correlation patterns among
genes [37], to eectively screen for hub genes closely
associated with phenotypes. MEturquoise (0 h) and
MEblue (12h) had the highest correlations with brotic
liver regeneration, suggesting that the expression of hub
genes exhibited the most signicant changes in the early
stage of liver regeneration. Using an ischemia-reperfusion
85% hepatectomy mouse model and mRNA microarray
analysis, Liu et al. [38] performed WGCNA and showed
that the changes of hub gene expression were most sig-
nicant during 6–24h after hepatectomy. Furthermore,
Zhu [39] conducted WGCNA based on a rat portal vein
ligation model and transcriptome-wide sequencing and
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 8 of 12
Wang et al. BMC Genomics (2023) 24:417
revealed that the changes in hub gene expression were
most signicant at 0h after operation. ese ndings are
consistent with and further support our results.
We also performed a series of functional enrichment
analyses based on bioinformatic knowledge from GO and
KEGG pathway databases. e results demonstrated that
the up-regulated hub genes were mainly associated with
biological processes, such as regulation of cell growth,
protein and nucleotide processing and synthesis, and
extracellular matrix organization, which is consistent
with liver regeneration being primarily driven by hepa-
tocyte proliferation [40]. Cellular proliferation requires
a signicant amount of nucleotides for the synthesis of
RNAs involved in transcription and translation [41], and
regulatory proteins such as cytokines and growth factors
also play crucial roles [42]. Moreover, the extracellular
matrix provides a framework for hepatocytes and main-
tains homeostasis in the liver [43]. Over-deposition of
diuse extracellular matrix is a key feature of liver bro-
sis, and extracellular matrix degradation and remodeling
are important steps in liver regeneration [44]. e down-
regulated hub genes in this study were mainly enriched
in biological processes such as fatty acid metabolic pro-
cess, cholesterol metabolic process, steroid hormone
Fig. 4 Identification of lncRNA-mRNA and circRNA-mRNA core pairs. A lncRNA–mRNA cis-regulatory core network. B lncRNA–mRNA trans-regulatory
core network. Red, lncRNA; turquoise, hub genes in MEturquoise; and blue, hub genes in MEblue.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 9 of 12
Wang et al. BMC Genomics (2023) 24:417
biosynthesis, and branched-chain amino acid degrada-
tion. Lipid metabolism has an important role in liver
regeneration [42, 45]. Indeed, fatty acid oxidation is the
main source of energy for liver regeneration, and inhibi-
tion of fatty acid β-oxidation has been reported to delay
liver regeneration after hepatectomy [46]. Cholesterol
aects liver regeneration by regulating cell cycle progres-
sion [47], and steroids inhibit liver regeneration by sup-
pressing TNF-α and IL-6 overproduction and hepatocyte
DNA synthesis [48, 49]. Moreover, amino acids also have
a crucial role in liver regeneration. Valine, leucine, and
isoleucine, which are collectively known as branched-
chain amino acids, can promote liver regeneration by
enhancing hepatocyte growth factor secretion and pro-
tein synthesis [50, 51]. erefore, our ndings are con-
sistent with processes that are known to underlie liver
regeneration.
In the present study, lncRNA/circRNA–miRNA–
mRNA regulatory networks were constructed by
investigating the mechanisms of lncRNA cis and trans
interactions, circRNA parental genes, and ceRNA inter-
actions. Compared to existing transcriptome-wide stud-
ies on liver regeneration, this work provides a more
comprehensive analysis of the mechanisms of action
of ncRNAs [52, 53]. Among the lncRNA/circRNA–
miRNA–mRNA ceRNA core regulatory networks identi-
ed in our study, we selected two pathways for RT-qPCR
validation: lncRNA-Xist/miR-144-3P/mRNA-Aplp2,
which was downregulated by liver regeneration; and cir-
cRNA-0000117/miRNA-204-5p/mRNA-Derl1, which was
upregulated. Our results show that the relative expression
levels of the RNAs in these pathways were highly consis-
tent with the results of high-throughput RNA sequenc-
ing. Notably, the change patterns of ncRNAs and mRNAs
in the two pathways conformed to the ceRNA hypoth-
esis, which further arms the reliability of our analysis.
Studies have shown that lncRNA-XIST promotes the
proliferation of pancreatic and lung cancer cells by tar-
geting and inhibiting miR-133a and miR-144-3p, respec-
tively [54, 55]. Moreover, circ-0000117 promotes the
Fig. 5 Identification of ceRNA core regulatory networks. (A) lncRNA–miRNA–mRNA core network. (B) circRNA–miRNA–mRNA core network. Red, ln-
cRNA/circRNA; yellow, miRNA; turquoise, hub genes in MEturquoise; blue, hub genes in MEblue.
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 10 of 12
Wang et al. BMC Genomics (2023) 24:417
proliferation of gastric cancer cells by inhibiting the miR-
337-3p/STAT3 axis [56]. Studies have also demonstrated
that miR-204 down-regulates the expression of Bcl-2,
Sirt1, and Fn-1 to inhibit the proliferation and promote
the apoptosis of hepatoma cells and tumor endothelial
cells [57, 58]. Taken together, we speculate that the above
pathways also have important roles in liver regeneration
by regulating cell proliferation and apoptosis.
ere are some limitations in our study. First, liver
brosis can arise from a range of chronic liver diseases,
such as viral hepatitis, alcoholic hepatitis, non-alcoholic
fatty liver, and autoimmune hepatitis. While our model
demonstrated consistent liver brosis features, it is inca-
pable of simulating all pathological alterations resulting
from dierent diseases. Second, although we examined
several mechanisms of ncRNA regulatory networks, such
as lncRNA cis and trans interactions, circRNA paren-
tal genes, and ceRNA pathways, there is still a need for
further exploration of additional mechanisms, includ-
ing protein binding and interaction, due to the intricate
nature of ncRNA mechanisms. Finally, through bioin-
formatics analysis, we predicted the regulatory networks
of ncRNAs and hub genes during the proliferative phase
of liver regeneration. However, the functions of the core
networks and pathways across the time spectrum need to
be experimentally veried in the future.
Conclusions
In this study, we revealed the expression patterns of
lncRNAs, circRNAs, miRNAs, and mRNAs in the pro-
liferative phase of liver regeneration in mice with liver
brosis. We identied hub mRNAs and constructed
lncRNA/circRNA–miRNA–mRNA regulatory net-
works. is study contributes to the understanding of the
molecular mechanisms of brotic liver regeneration. Our
ndings provide new insights into the process of liver
regeneration and potential targets for preclinical studies.
Supplementary Information
The online version contains supplementary material available at https://doi.
org/10.1186/s12864-023-09478-z.
Additional le 1: Supplementary Table S1. Sequences of PCR primers.
Additional le 2: Supplementary Table S2. Summary of all lncRNAs,
circRNAs, miRNAs, and mRNAs identified in this study.
Additional le 3: Supplementary Table S3. Summary of all DE lncRNAs,
DE circRNAs, DE miRNA and DE mRNAs identified in this study.
Additional le 4: Supplementary Table S4. DE mRNAs of each WGCNA
modules.
Additional le 5: Supplementary Table S5. miRNA-RNA targets pre-
dicted by Starbase.
Additional le 6: Supplementary Table S6. miRNA-RNA targets pre-
dicted by miRanda.
Additional le 7: Supplementary Fig. S1. Gross observation, Microscop-
ic observation of liver from mice with liver fibrosis A Gross observation of
liver from mice with liver fibrosis. B Hematoxylin and eosin staining (×100).
C Masson staining (×100). D-F Ki-67 immunohistochemistry at 0 h (D), 12 h
(E), and 72 h (F) after hepatectomy.
Additional le 8: Supplementary Fig. S2. Volcano plots of differentially
expressed genes in the proliferative phase of liver regeneration.
Additional le 9: Supplementary Fig. S3. Functional analysis of lncRNA-
mRNA and circRNA-mRNA core pairs. A GO enrichment analysis of lncRNA
cis-regulatory targets. B KEGG enrichment analysis of lncRNA cis-regulatory
targets C GO enrichment analysis of lncRNA trans-regulatory targets. D
Fig. 6 Releative expression levels of lncRNAs, circRNAs, miRNAs, and mRNAs in ceRNA networks. The black bar shows the qRT-PCR data and the the gray
bar shows the RNA-seq data. *P < 0.05 and **P < 0.01 for comparisons between groups
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Page 11 of 12
Wang et al. BMC Genomics (2023) 24:417
KEGG enrichment analysis of lncRNA trans-regulatory targets. E GO enrich-
ment analysis of circRNA parental genes.
Acknowledgements
Not applicable.
Authors’ contributions
Qian Wang performed the research. Fengfeng Zhu, Huajian Li, Zhiqiang Xiang,
Hao Liang, Yachen Wu analyzed the data. Zhangtao Long, Huajian Li wrote the
manuscript. Xiaoming Dai, Zhu Zhu designed the study. All authors approved
the manuscript.
Funding
This study was funded by Natural Science Foundation of Hunan Province
(Grant No. 2021JJ70120, Grant No. 2022JJ70119) and Clinical Medicine
Technological Innovation Leading Project of Hunan Province (Grant No.
2020SK51818).
Data availability
The datasets supporting the conclusions of this article are included within
the article and its additional files. The transcriptome sequencing data publicly
available at BioProject database under the BioProject ID PRJNA953495.
Declarations
Ethics approval and consent to participate
All of the animal procedures were performed in accordance with the Guide for
the Care and Use of Laboratory Animals of the People’s Republic of China and
approved by the Animal Ethics Committee of University of south china. This
study was carried out in compliance with the ARRIVE guidelines.
Consent for publication
Not applicable.
Competing interest
The authors declare that they have no competing interests.
Author details
1The First Affiliated Hospital, Department of Reproductive Medicine,
Hengyang Medical School, University of South China, Hengyang,
Hunan 421001, China
2The First Affiliated Hospital, Department of Hepatobiliary Surgery,
Hengyang Medical School, University of South China, Hengyang,
Hunan 421001, China
3The First Affiliated Hospital, Department of Education and Training,
Hengyang Medical School, University of South China, Hengyang,
Hunan 421001, China
Received: 24 April 2023 / Accepted: 22 June 2023
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... The NASH group was given the Gubra-Amylin-NASH diet (D09100310, 40% fat, 22% fructose, and 2% cholesterol) for 12 weeks (Boland et al., 2019;Fujisawa et al., 2021). Then, the left and middle lobes of the liver were resected according to our previous studies (Lei et al., 2022;Dai et al., 2023;Wang et al., 2023). The mice were anesthetized and sacrificed at 0 h (sham group), 6, 24, 48, 72, and 168 h following the 70% hepatectomy (six mice at each time point). ...
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Objective Amino acid (AA) metabolism plays a vital role in liver regeneration. However, its measuring utility for post-hepatectomy liver regeneration under different conditions remains unclear. We aimed to combine machine learning (ML) models with AA metabolomics to assess liver regeneration in health and non-alcoholic steatohepatitis (NASH). Methods The liver index (liver weight/body weight) was calculated following 70% hepatectomy in healthy and NASH mice. The serum levels of 39 amino acids were measured using ultra-high performance liquid chromatography–tandem mass spectrometry analysis. We used orthogonal partial least squares discriminant analysis to determine differential AAs and disturbed metabolic pathways during liver regeneration. The SHapley Additive exPlanations algorithm was performed to identify potential AA signatures, and five ML models including least absolute shrinkage and selection operator, random forest, K-nearest neighbor (KNN), support vector regression, and extreme gradient boosting were utilized to assess the liver index. Results Eleven and twenty-two differential AAs were identified in the healthy and NASH groups, respectively. Among these metabolites, arginine and proline metabolism were commonly disturbed metabolic pathways related to liver regeneration in both groups. Five AA signatures were identified, including hydroxylysine, L-serine, 3-methylhistidine, L-tyrosine, and homocitrulline in healthy group, and L-arginine, 2-aminobutyric acid, sarcosine, beta-alanine, and L-cysteine in NASH group. The KNN model demonstrated the best evaluation performance with mean absolute error, root mean square error, and coefficient of determination values of 0.0037, 0.0047, 0.79 and 0.0028, 0.0034, 0.71 for the healthy and NASH groups, respectively. Conclusion The KNN model based on five AA signatures performed best, which suggests that it may be a valuable tool for assessing post-hepatectomy liver regeneration in health and NASH.
... Numerous circRNAs are demonstrated to be involved in the progression of a number of diseases, and because of their conservation, stability, specificity, richness and easy detection (20) they not only point out a new direction for clinical treatment, but also provide new markers for the early diagnosis of BA. A number of circRNAs also provide novel ideas for clarifying the mechanism of the circRNA-miRNA axis in the process of liver fibrosis (21,22). ...
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Circular RNAs (circRNAs) serve an essential role in the occurrence and development of cholangiocarcinoma, but the expression and function of circRNA in biliary atresia (BA) is not clear. In the present study, circRNA expression profiles were investigated in the liver tissues of patients with BA as well as in the choledochal cyst (CC) tissues of control patients using RNA sequencing. A total of 78 differentially expressed circRNAs (DECs) were identified between the BA and CC tissues. The expression levels of eight circRNAs (hsa_circ_0006137, hsa_circ_0079422, hsa_circ_0007375, hsa_circ_0005597, hsa_circ_0006961, hsa_circ_0081171, hsa_circ_0084665 and hsa_circ_0075828) in the liver tissues of the BA group and control group were measured using reverse transcription-quantitative polymerase chain reaction. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis demonstrated that the identified DECs are involved in a variety of biological processes, including apoptosis and metabolism. In addition, based on the GO and KEGG pathway enrichment analyses, it was revealed that target genes that can be affected by circRNAs regulatory network were enriched in the TGF-β signaling pathway, EGFR tyrosine kinase inhibitor resistance pathway and transcription factor regulation pathway as well as other pathways that may be associated with the pathogenesis of BA. The present study revealed that circRNAs are potentially implicated in the pathogenesis of BA and could help to find promising targets and biomarkers for BA.
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Non-alcoholic fatty liver disease (NAFLD) is a clinicopathologic syndrome caused by fat deposition in hepatocytes. Patients with nonalcoholic steatohepatitis (NASH), an advanced form of NAFLD with severe fibrosis, are at high risk for liver-related complications, including hepatocellular carcinoma (HCC). However, the mechanism of progression from simple fat deposition to NASH is complex, and previous reports have linked NAFLD to gut microbiota, bile acids, immunity, adipokines, oxidative stress, and genetic or epigenetic factors. NASH-related liver injury involves multiple cell types, and intercellular signaling is thought to be mediated by extracellular vesicles. MicroRNAs (miRNAs) are short, noncoding RNAs that play important roles as post-transcriptional regulators of gene expression and have been implicated in the pathogenesis of various diseases. Recently, many reports have implicated microRNAs in the pathogenesis of NALFD/NASH, suggesting that exosomal miRNAs are potential non-invasive and sensitive biomarkers and that the microRNAs involved in the mechanism of the progression of NASH may be potential therapeutic target molecules. We are interested in which miRNAs are involved in the pathogenesis of NASH and which are potential target molecules for therapy. We summarize targeted miRNAs associated with the etiology and progression of NASH and discuss each miRNA in terms of its pathophysiology, potential therapeutic applications, and efficacy as a NASH biomarker.
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KEGG (https://www.kegg.jp) is a manually curated database resource integrating various biological objects categorized into systems, genomic, chemical and health information. Each object (database entry) is identified by the KEGG identifier (kid), which generally takes the form of a prefix followed by a five-digit number, and can be retrieved by appending /entry/kid in the URL. The KEGG pathway map viewer, the Brite hierarchy viewer and the newly released KEGG genome browser can be launched by appending /pathway/kid, /brite/kid and /genome/kid, respectively, in the URL. Together with an improved annotation procedure for KO (KEGG Orthology) assignment, an increasing number of eukaryotic genomes have been included in KEGG for better representation of organisms in the taxonomic tree. Multiple taxonomy files are generated for classification of KEGG organisms and viruses, and the Brite hierarchy viewer is used for taxonomy mapping, a variant of Brite mapping in the new KEGG Mapper suite. The taxonomy mapping enables analysis of, for example, how functional links of genes in the pathway and physical links of genes on the chromosome are conserved among organism groups.
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Background & aims: Transient regeneration-associated steatosis (TRAS) is a process of temporary hepatic lipid accumulation and is essential for liver regeneration by providing energy generated from fatty acid β-oxidation, but the regulatory mechanism underlying TRAS remains unknown. Parkinsonism-associated deglycase (Park7)/Dj1 is an important regulator involved in various liver diseases. In nonalcoholic fatty liver diseased mice, induced by a high-fat diet, Park7 deficiency improves hepatic steatosis, but its role in liver regeneration remains unknown METHODS: Park7 knockout (Park7-/- ), hepatocyte-specific Park7 knockout (Park7△hep ) and hepatocyte-specific Park7-Pten double knockout mice were subjected to 2/3 partial hepatectomy (PHx) RESULTS: Increased PARK7 expression was observed in the regenerating liver of mice at 36 and 48 h after PHx. Park7-/- and Park7△hep mice showed delayed liver regeneration and enhanced TRAS after PHx. PPARa, a key regulator of β-oxidation, and carnitine palmitoyltransferase 1a (CPT1a), a rate-limiting enzyme of β-oxidation, had substantially decreased expression in the regenerating liver of Park7△hep mice. Increased phosphatase and tensin homolog (PTEN) expression was observed in the liver of Park7△hep mice, which might contribute to delayed liver regeneration in these mice because genomic depletion or pharmacological inhibition of PTEN restored the delayed liver regeneration by reversing the downregulation of PPARa and CPT1a and in turn accelerating the utilization of TRAS in the regenerating liver of Park7△hep mice CONCLUSION: Park7/Dj1 is a novel regulator of PTEN-dependent fatty acid β-oxidation, and increasing Park7 expression might be a promising strategy to promote liver regeneration.
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Background Portal vein ligation (PVL)-induced liver hypertrophy increases future liver remnant (FLR) volume and improves resectability of large hepatic carcinoma. However, the molecular mechanism by which PVL facilitates liver hypertrophy remains poorly understood. Methods To gain mechanistic insight, we established a rat PVL model and carried out a comprehensive transcriptome analyses of hepatic lobes preserving portal blood supply at 0, 1, 7, and 14-day after PVL. The differentially expressed (DE) long-non coding RNAs (lncRNAs) and mRNAs were applied to conduct weighted gene co-expression network analysis (WGCNA). LncRNA-mRNA co-expression network was constructed in the most significant module. The modules and genes associated with PVL-induced liver hypertrophy were assessed through quantitative real-time PCR. Results A total of 4213 DElncRNAs and 6809 DEmRNAs probesets, identified by transcriptome analyses, were used to carry out WGCNA, by which 10 modules were generated. The largest and most significant module (marked in black_M6) was selected for further analysis. Gene Ontology (GO) analysis of the module exhibited several key biological processes associated with liver regeneration such as complement activation, IL-6 production, Wnt signaling pathway, autophagy, etc. Sixteen mRNAs (Notch1, Grb2, IL-4, Cops4, Stxbp1, Khdrbs2, Hdac2, Gnb3, Gng10, Tlr2, Sod1, Gosr2, Rbbp5, Map3k3, Golga2, and Rev3l) and ten lncRNAs (BC092620, AB190508, EF076772, BC088302, BC158675, BC100646, BC089934, L20987, BC091187, and M23890) were identified as hub genes in accordance with gene significance value, module membership value, protein–protein interaction (PPI) and lncRNA-mRNA co-expression network. Furthermore, the overexpression of 3 mRNAs (Notch1, Grb2 and IL-4) and 4 lncRNAs (BC089934, EF076772, BC092620, and BC088302) was validated in hypertrophic liver lobe tissues from PVL rats and patients undergoing hepatectomy after portal vein embolization (PVE). Conclusions Microarray and WGCNA analysis revealed that the 3 mRNAs (Notch1, Grb2 and IL-4) and the 4 lncRNAs (BC089934, EF076772, BC092620 and BC088302) may be promising targets for accelerating liver regeneration before extensive hepatectomy.
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In mouse models, the recovery of liver volume is mainly mediated by the proliferation of hepatocytes after partial hepatectomy that is commonly accompanied with ischemia-reperfusion. The identification of differently expressed genes in liver following partial hepatectomy benefits the better understanding of the molecular mechanisms during liver regeneration (LR) with appliable clinical significance. Briefly, studying different gene expression patterns in liver tissues collected from the mice group that survived through extensive hepatectomy will be of huge critical importance in LR than those collected from the mice group that survived through appropriate hepatectomy. In this study, we performed the weighted gene coexpression network analysis (WGCNA) to address the central candidate genes and to construct the free-scale gene coexpression networks using the identified dynamic different expressive genes in liver specimens from the mice with 85% hepatectomy (20% for seven-day survial rate) and 50% hepatectomy (100% for seven-day survial rate under ischemia-reperfusion condition compared with the sham group control mice). The WGCNA combined with Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses pinpointed out the apparent distinguished importance of three gene expression modules: the blue module for apoptotic process, the turquoise module for lipid metabolism, and the green module for fatty acid metabolic process in LR following extensive hepatectomy. WGCNA analysis and protein-protein interaction (PPI) network construction highlighted FAM175B, OGT, and PDE3B were the potential three hub genes in the previously mentioned three modules. This work may help to provide new clues to the future fundamental study and treatment strategy for LR following liver injury and hepatectomy.
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Circular RNA hsa_circ_0000117 is reportedly increased in Gastric cancer (GC), however, its role is unexplored. Hsa_circ_0000117 expression and function in GC was investigated using standard cell phenotypic and expression assays. Pull-down and luciferase reporter assays also elucidated hsa_circ_0000117 mechanisms. In the present study, we observed increased hsa_circ_0000117 and signal transducer and activator of transcription 3 (STAT3) expression, while microRNA-337-3p (miR-337-3p) was decreased in GC cells. Depleted hsa_circ_0000117 decreased GC proliferation and invasion. Hsa_circ_0000117 was also identified as a miR-337-3p sponge. Also, STAT3 was identified as a miR-337-3p target. Similarly, rescue assays indicated STAT3 overexpression (or miR-337-3p inhibition) reversed hsa_circ_0000117 effects in GC progression. Thus, our data suggested hsa_circ_0000117 exhibited oncogene properties in combination with the hsa_circ_0000117/miR-337-3p/STAT3 axis in GC, potentially providing a new therapeutic target for GC. Abbreviations GC: gastric cancer; STAT3: Signal transducer and activator of transcription 3; circRNA: Circular RNA; miRNA: microRNA; DMEM: Dulbecco’s modified Eagle’s medium; FBS: fetal bovine serum; PVDF: polyvinylidene fluoride; CCK-8: Cell counting kit-8; qRT-PCR: Quantitative real-time PCR; SDS-PAGE: sodium dodecyl sulfate polyacrylamide gel electrophoresis; TNM: TNM Classification of Malignant Tumors; mTOR: mechanistic target of rapamycin; ANOVA: one-way analysis of variance
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Liver fibrosis is an abnormal wound repair response caused by a variety of chronic liver injuries, which is characterized by over-deposition of diffuse extracellular matrix (ECM) and anomalous hyperplasia of connective tissue, and it may further develop into liver cirrhosis, liver failure or liver cancer. To date, chronic liver diseases accompanied with liver fibrosis have caused significant morbidity and mortality in the world with increasing tendency. Although early liver fibrosis has been reported to be reversible, the detailed mechanism of reversing liver fibrosis is still unclear and there is lack of an effective treatment for liver fibrosis. Thus, it is still a top priority for the research and development of anti-fibrosis drugs. In recent years, many strategies have emerged as crucial means to inhibit the occurrence and development of liver fibrosis including anti-inflammation and liver protection, inhibition of hepatic stellate cells (HSCs) activation and proliferation, reduction of ECM overproduction and acceleration of ECM degradation. Moreover, gene therapy has been proved to be a promising anti-fibrosis method. Here, we provide an overview of the relevant targets and drugs under development. We aim to classify and summarize their potential roles in treatment of liver fibrosis, and discuss the challenges and development of anti-fibrosis drugs.
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Chronic liver injury leads to liver inflammation and fibrosis, through which activated myofibroblasts in the liver secrete extracellular matrix proteins that generate the fibrous scar. The primary source of these myofibroblasts are the resident hepatic stellate cells. Clinical and experimental liver fibrosis regresses when the causative agent is removed, which is associated with the elimination of these activated myofibroblasts and resorption of the fibrous scar. Understanding the mechanisms of liver fibrosis regression could identify new therapeutic targets to treat liver fibrosis. This Review summarizes studies of the molecular mechanisms underlying the reversibility of liver fibrosis, including apoptosis and the inactivation of hepatic stellate cells, the crosstalk between the liver and the systems that orchestrate the recruitment of bone marrow-derived macrophages (and other inflammatory cells) driving fibrosis resolution, and the interactions between various cell types that lead to the intracellular signalling that induces fibrosis or its regression. We also discuss strategies to target hepatic myofibroblasts (for example, via apoptosis or inactivation) and the myeloid cells that degrade the matrix (for example, via their recruitment to fibrotic liver) to facilitate fibrosis resolution and liver regeneration.
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Characterized by compensatory hyperplasia dependent on hepatocyte proliferation, the liver will initiate regeneration after partial hepatectomy (PH) and acute or chronic injuries. A variety of genes and noncoding RNAs play pivotal roles in these cell proliferation and growth processesPDK1. However, it is still unclear how competition endogenous RNAs (ceRNAs) modulate cellular activities during each phase of liver regeneration, and the specific mechanisms of posttranscriptional gene expression regulation in hepatocyte proliferation remain to be elucidated. To investigate the mechanism of liver regeneration through RNA-seq profiling and to determine the role of miR-34b-5p/PDK1 on hepatocyte proliferation, we established a 2/3 PH mouse model for whole transcriptome profiling based on high-throughput sequencing techniques. We subsequently constructed a lncRNA-miRNA-mRNA ceRNA regulatory network through integrative analyses of RNA interactions. Finally, plasmid transfection in NCTC 1469 cells, dual luciferase reporter gene assay, quantitative real-time PCR, western blotting, Cell Counting Kit-8, and EdU-DNA synthesis cell proliferation assay were used to demonstrate the role of the miR-34b-5p/PDK1 axis in hepatocyte proliferation in vitro. A total of 1443 mRNAs (962 up, 481 down), 48 miRNAs (35 up, 13 down), and 1955 lncRNAs (986 up, 969 down) were identified as significantly differentially expressed. We then successfully constructed a ceRNA regulatory network consisting of 7 lncRNAs, 15 miRNAs, and 347 mRNAs based on the predicted inverse interactions among ceRNAs. Additionally, miR-34b-5p/PDK1 was predicted to be closely related to hepatocyte proliferation. We further demonstrated that miR-34b-5p could bind specifically to the 3′-untranslated region (3′-UTR) of PDK1 using the dual luciferase reporter assay. Ectopic overexpression of miR-34b-5p significantly reduced the mRNA and protein expression of PDK1, while it markedly inhibited the proliferation of mouse NCTC 1469 cells in vitro. In contrast, knocking down miR-34b-5p exhibited the inverse effects on PDK1 expression and hepatocyte proliferation. Through analyzing the ceRNA network during mouse liver regeneration, this study reveals that miR-34b-5p can inhibit hepatocyte proliferation through negatively regulating PDK1 and may be a potential pharmacological intervention target.
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Despite the crucial role of cell metabolism in biological processes, particularly cell division, metabolic aspects of liver regeneration are not well defined. Better understanding of the metabolic activity governing division of liver cells will provide powerful insights into mechanisms of physiological and pathological liver regeneration. Recent studies have provided evidence that metabolic response to liver failure might be a proximal signal to initiate cell proliferation in liver regeneration. In this review, we highlight how lipids, carbohydrates, and proteins dynamically change and orchestrate liver regeneration. In addition, we discuss translational studies in which metabolic intervention has been used to treat chronic liver diseases (CLDs).
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The liver has an excellent capacity for regeneration when faced with external injury and the damage differs from that of other organs in the body. Our aim was to identify the role of circular RNA (circRNA) during the DNA synthesis phase (36 h) of mice liver regeneration. High-throughput RNA sequencing was conducted to explore circRNA and messenger RNA (mRNA) expression in three pairs of mice liver tissue at 0 and 36 h after 2/3 partial hepatectomy. One hundred differentially expressed circRNAs were detected, including 66 upregulated and 34 downregulated circRNAs. We also explored 2483 differentially expressed mRNAs, including 1422 upregulated and 1061 downregulated mRNAs. Gene ontology and Kyoto Encyclopedia of Genes and Genomes indicated that cell cycle regulation, material metabolism, and multiple classical pathways were involved in the DNA synthesis process. A competing endogenous RNA (ceRNA) network containing 5 circRNAs, 28 target genes, and 533 microRNAs (miRNAs) was constructed, and we selected the top 5 miRNAs to map it. Potential key circRNAs were validated with the quantitative real-time PCR technique and their regeneration curves, including consecutive time points, were produced. Finally, a cell counting kit-8 assay on key circRNAs of ceRNA network was performed to further confirm their roles in the DNA synthesis phase of liver regeneration. This study provides a circRNA expression profile for liver regeneration and contributes valuable information for future research.