ArticlePublisher preview availableLiterature Review

Autophagy: a promising therapeutic target for improving mesenchymal stem cell biological functions

February 2021
Molecular and Cellular Biochemistry 476(2):1-15

February 2021
476(2):1-15

Authors:

Mesenchymal stem cells (MSCs) are considered to be a promising therapeutic material due to their capacities for self-renewal, multilineage differentiation, and immunomodulation and have attracted great attention in regenerative medicine. However, MSCs may lose their biological functions because of donor age or disease and environmental pressure before and after transplantation, which hinders the application of MSC-based therapy. As a major intracellular lysosome-dependent degradative process, autophagy plays a pivotal role in maintaining cellular homeostasis and withstanding environmental pressure and may become a potential therapeutic target for improving MSC functions. Recent studies have demonstrated that the regulation of autophagy is a promising approach for improving the biological properties of MSCs. More in-depth investigations about the role of autophagy in MSC biology are required to contribute to the clinical application of MSCs. In this review, we focus on the role of autophagy regulation by various physical and chemical factors on the biological functions of MSCs in vitro and in vivo, and provide some strategies for enhancing the therapeutic efficacy of MSCs.

Autophagy pathway in mammalian cells. Autophagy formation is associated with a series of autophagy-related proteins and protein complexes. This process involves the formation of a phagophore, the engulfment of cytoplasmic substances, and the elongation of the phagophore membrane, which ultimately fuses with the lysosome to form autolysosomes

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Signaling in autophagy regulation. A brief overview of the signaling pathways that regulate autophagy is presented in the schematic, including mTOR-dependent pathways (PI3K/AKT/mTOR, AMPK, p53, and MAPK/Erk1/2 signaling pathways) and mTOR-independent pathways (Ca⁺, calpain, cAMP, and IP3 signaling pathways)

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Roles of autophagy in maintaining the functional properties of MSCs. The induction of autophagy through physical or chemical factors in MSCs promotes the survival and angiogenesis of MSCs. HG-induced autophagy is involved in MSC senescence, but Mel, RAP, and CH can alleviate aging cellular phenotypes of senescent MSCs by activating autophagy. Similarly, the role of autophagy in regulating the immunosuppressive capacity of MSCs is controversial; inflammatory microenvironment-induced autophagy exerts a negative effect on the immunomodulatory activity of MSCs, and treatment with RAP can enhance the immunosuppressive properties of MSCs by increasing the production of COX-2, PGE2, TGF-β1, IL-10, and IDO. In addition, the induction of autophagy suppresses the chondrogenic differentiation of MSCs and enhances the osteogenic, adipogenic, neuronal, and myogenic differentiation of MSCs

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Molecular and Cellular Biochemistry (2021) 476:1135–1149

https://doi.org/10.1007/s11010-020-03978-2

Autophagy: apromising therapeutic target forimproving

mesenchymal stem cell biological functions

JiaqiangDeng1· LijunZhong1· ZihanZhou1· CongweiGu1,2· XiaoyaHuang1· LiuhongShen1· SuizhongCao1·

ZhihuaRen1· ZhicaiZuo1· JunliangDeng1· ShuminYu1

Received: 3 July 2020 / Accepted: 6 November 2020 / Published online: 16 November 2020

Abstract

Mesenchymal stem cells (MSCs) are considered to be a promising therapeutic material due to their capacities for self-renewal,

multilineage diﬀerentiation, and immunomodulation and have attracted great attention in regenerative medicine. However,

MSCs may lose their biological functions because of donor age or disease and environmental pressure before and after trans-

plantation, which hinders the application of MSC-based therapy. As a major intracellular lysosome-dependent degradative

process, autophagy plays a pivotal role in maintaining cellular homeostasis and withstanding environmental pressure and

may become a potential therapeutic target for improving MSC functions. Recent studies have demonstrated that the regula-

tion of autophagy is a promising approach for improving the biological properties of MSCs. More in-depth investigations

about the role of autophagy in MSC biology are required to contribute to the clinical application of MSCs. In this review,

we focus on the role of autophagy regulation by various physical and chemical factors on the biological functions of MSCs

invitro and invivo, and provide some strategies for enhancing the therapeutic eﬃcacy of MSCs.

Keywords MSCs· Autophagy· Immunosuppression· Diﬀerentiation· Survival· Angiogenesis

Abbreviations

AD-MSCs Adipose tissue-derived mesenchymal

stem cells

ADM Adrenomedullin

AMBRA1 Activating molecule in Beclin-1 regu-

lated autophagy

AMPK Adenosine monophosphate-activated

protein kinase

ATG Autophagy-related genes

ATV Atorvastatin

BECN1 Bcl-2 interacting protein 1, also known

as Beclin-1

bFGF Basic ﬁbroblast growth factor

BMSCs Bone marrow mesenchymal stem cells

CCL Chemokine (C-C motif) ligand

CH Cholesterol

CP-MSCs Placental chorionic plate-derived mes-

enchymal stem cells

CXCL Chemokine (C-X-C motif) ligand

CX3CL CX3C chemokine ligand

Dex Dexamethasone

FIP200 FAK family-interacting protein of

200kDa

ENA-78 Epithelial neutrophil-activating protein

ER Endoplasmic reticulum

GATA-4 GATA-binding protein 4

GDNF Glialcellline-derived neurotrophic

factor

GRO Growth-regulated oncogene

HG High glucose

HGF Hepatocyte growth factor

HIF-1α Hypoxia-inducible factor-1α

HLA Human leukocyte antigen

HO-1 Heme oxygenase-1

H/SD Hypoxia/serum deprivation

IDO Indoleamine2,3-dioxigenase

IGF-1 Insulin-like growth factor-1

Jia-Qiang Deng and Li-Jun Zhong contributed equally to this work

* Shumin Yu

yayushumin@sicau.edu.cn

1 Department ofClinical Veterinary Medicine, College

ofVeterinary Medicine, Sichuan Agricultural University,

Chengdu, China

2 Laboratory Animal Centre, Southwest Medical University,

Luzhou, China

Content courtesy of Springer Nature, terms of use apply. Rights reserved.

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Background:Mesenchymal stem cell (MSC)-based cell transplantation is an effective means of treating chronic liver injury, fibrosis and end-stage liver disease. However, extensive studies have found that only a small number of transplanted cells migrate to the site of injury or lesion, and repair efficacy is very limited. Methods:Bone marrow-derived MSCs (BM-MSCs) were generated that overexpressed the erythropoietin (EPO) gene using a lentivirus. Cell Counting Kit-8 was used to detect the viability of BM-MSCs after overexpressing EPO. Cell migration and apoptosis were verified using Boyden chamber and flow cytometry, respectively. Finally, the anti-fibrosis efficacy of EPO-MSCs was evaluated in vivo using immunohistochemical analysis.Results:EPO overexpression promoted cell viability and migration of BM-MSCs without inducing apoptosis, and EPO-MSC treatment significantly alleviated liver fibrosis in a carbon tetrachloride (CCl4) induced mouse liver fibrosis model.Conclusion:EPO-MSCs enhance anti-fibrotic efficacy, with higher cell viability and stronger migration ability compared with treatment with BM-MSCs only. These findings support improving the efficiency of MSCs transplantation as a potential therapeutic strategy for liver fibrosis.

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A Comparative Study of Biological Characteristics and Transcriptome Profiles of Mesenchymal Stem Cells from Different Canine Tissues

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Mar 2019
INT J MOL SCI

Mesenchymal stem cells (MSCs) are the most promising seed cells for cell therapy. Comparing the biological and transcriptome gene characteristics of MSCs from different sources provides an important basis for the screening of clinically used cells. The main purpose of this experiment was to establish methods for the isolation and culture of MSCs from five different canine sources, including adipose tissue, bone marrow, umbilical cord, amniotic membrane, and placenta, and compare biological and transcriptome characteristics of MSCs, in order to provide a basis for the clinical application of canine MSCs. MSCs were isolated from Chinese pastoral dogs, and the following experiments were performed: (1) the third, sixth, and ninth generations of cells were counted, respectively, and a growth curve was plotted to calculate the MSC population doubling time; (2) the expression of CD34 and CD44 surface markers was studied by immunofluorescence; (3) the third generation of cells were used for osteogenetic and adipogenic differentiation experiments; and (4) MSC transcriptome profiles were performed using RNA sequencing. All of the five types of MSCs showed fibroblast-like adherent growth. The cell surface expressed CD44 instead of CD34; the third-generation MSCs had the highest proliferative activity. The average population doubling time of adipose mesenchymal stem cells (AD-MSCs), placenta mesenchymal stem cells (P-MSCs), bone marrow mesenchymal stem cells (BM-MSCs), umbilical cord mesenchymal stem cells (UC-MSCs), and amniotic mesenchymal stem cells (AM-MSCs) were 15.8 h, 21.2 h, 26.2 h, 35 h, and 41.9 h, respectively. All five types of MSCs could be induced to differentiate into adipocytes and osteoblasts in vitro, with lipid droplets appearing after 8 days and bone formation occurring 5 days after AD-MSC induction. However, the multilineage differentiation for the remaining of MSCs was longer compared to that of the AD-MSCs. The MSC transcriptome profiles showed that AD-MSC and BM-MSCs had the highest homology, while P-MSCs were significantly different compared to the other four types of MSCs. All the isolated MSCs had the main biological characteristics of MSCs. AD-MSCs had the shortest time for proliferation, adipogenesis, and osteogenic differentiation.

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After in vivo transplantation, mesenchymal stem cells (MSC) face an ischemic microenvironment, characterized by nutrient deprivation and reduced oxygen tension, which reduces their viability and thus their therapeutic potential. Therefore, MSC response to models of in vitro ischemia is of relevance for improving their survival and therapeutic efficacy. The aim of this study was to understand the survival/adaptive response mechanism that MSC use to respond to extreme culture conditions. Specifically, the effect of a long-term starvation on human bone marrow (hBM)-derived MSC cultured in a chemically defined medium (fetal bovine serum-free [SF] and human SF), either in hypoxic or normoxic conditions. We observed that hBM-MSC that were isolated and cultured in SF medium and subjected to a complete starvation for up to 75 days transiently changed their behavior and phenotype. However, at the end of that period, hBM-MSC retained their characteristics as determined by their morphology, DNA damage resistance, proliferation kinetic, and differentiation potential. This survival mode involved a quiescent state, confirmed by increased expression of cell cycle regulators p16, p27, and p57 and decreased expression of proliferating cell nuclear antigen (PCNA), Ki-67, mTOR, and Nanog. In addition, Jak/STAT (STAT6) antiapoptotic activity selected which cells conserved stemness and that supported metabolic, bioenergetic, and scavenging requirements. We also demonstrated that hBM-MSC exploited an autophagic process which induced lipid β-oxidation as an alternative energy source. Priming MSC by concomitant starvation and culture in hypoxic conditions to induce their quiescence would be of benefit to increase MSC survival when transplanted in vivo. Stem Cells 2019;37:813-827.

Differentiation Regulation of Mesenchymal Stem Cells via Autophagy induced by Structurally-different Silica Based Nanobiomaterials

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Feb 2019

Autophagy is associated with the proliferation and differentiation of mesenchymal stem cells (MSCs). In this study, we investigated the biological impact of silica-based nanobiomateiral-induced autophagy on the differentiation of MSCs, in which the nanoparticulate cues include solid silica nanoparticles (SSN), mesoporous silica nanoparticles (MSN) and biodegradable mesoporous silica nanoparticles (DMSN). The treatment with SSN significantly up-regulated LC3-II expression via ERK1/2 and AKT/mTOR signaling pathway compared to DMSN and MSN, leading to higher autophagic activity in MSCs. The enhanced protein adsorption of DMSN and MSN could prevent the direct interaction between cells and nanoparticle, consequently reduce the autophagic stimulation to MSCs. It should be noted that MSCs displayed increased differentiation potential when the autophagic activity was enhanced by the treatment with different nanoparticles. In comparison, no difference in cell differentiation potential was found when autophagy inhibitor (chloroquine, CQ) was incorporated in all groups. The study may contribute to the development of silica-based nanobiomaterials in the future.

Bone marrow–derived mesenchymal stromal cells ameliorate severe acute pancreatitis in rats via hemeoxygenase-1–mediated anti-oxidant and anti-inflammatory effects

Article

Dec 2018

Background and aims: It has been previously verified that mesenchymal stromal cells (MSCs) have a good therapeutic effect on severe acute pancreatitis (SAP) and the potential for regeneration of damaged pancreatic tissue, but the exact molecular mechanism remains unclear. In this study, we demonstrated the therapeutic effect of bone morrow MSCs (BMSCs) on SAP, probably by targeting heme oxygenase-1 (HO-1). Methods: Six hours after SAP induction, either phosphate-buffered saline (PBS) or BMSCs were transfused into the caudal vein of rats, zinc protoporphyrin (ZnPP) was administered intraperitoneally. Pancreatic pathological scoring, serum levels of amylase and inflammatory factors, as well as levels of reactive oxygen species (ROS), malondialdehyde (MDA) and myeloperoxidase (MPO), superoxide dismutase (SOD) and catalase (CAT) activity in the pancreas were evaluated. Results: Our data showed that BMSCs significantly reduce inflammation and oxidative stress, reduce apoptosis and promote angiogenesis of damaged pancreas. Moreover, BMSCs increased the level of HO-1 in the serum and pancreatic tissue in rats with SAP. In addition, the protective effect of BMSCs was partially neutralized by the HO-1 activity inhibitor ZnPP, suggesting a key role of HO-1 in the therapeutic effect of BMSCs on SAP. Conclusions: BMSCs ameliorated SAP, probably by inducing expression of HO-1, which can exert anti-inflammatory and anti-oxidant effects, reduce apoptosis and promote angiogenesis.

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