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(A) Heat map of the differentially expressed (DE) mRNAs coding for proteins involved in cell cycle regulation in HepG2 cells treated with 1 μM, 5 μM and 10 μM crambescin C1 (CC1) with respect to control cells. Green color represents mRNA down-regulation of treated cells with respect to controls; (B) Centroid graph for down-regulated genes showed in A. * Significant differences with respect to controls and 5 μM treated cells, p < 0.05, n = 3; (C) Quantification of the cell population percentages in each phase of the cell cycle in control and HepG2 cells treated with 0.3 μM, 1 μM, 5 μM and 10 μM CC1 for 24 h. (p < 0.01, n = 2); (D) Analysis of the relative fluorescence intensity of the stained nuclei. Histograms indicate the differences in the relative proportions of cells in G0/G1 and G2/M phases between control and 10 μM CC1 treated cells.
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The Mediterranean marine sponge Crambe crambe is the source of two families of guanidine alkaloids known as crambescins and crambescidins. Some of the biological effects of crambescidins have been previously reported while crambescins have undergone little study. Taking this into account, we performed comparative transcriptome analysis to examine t...
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Context 1
... initially determined by MTT, CC1 inhibits cell proliferation. Microarrays results showed that CC1 negatively affected the cell cycle progression down-regulating the expression of cyclins A, B, D, and E ( Figure 5A,B). According to this, a G0/G1 arrest could be expected. ...
Context 2
... confirm this possibility, HepG2 cells were treated with 0.3 μM, 1 μM, 5 μM and 10 μM CC1 for 24 h and analyzed by flow cytometry. CC1 did not cause any significant restriction of the cell cycle progression at 0.3 μM, 1 μM and 5 μM ( Figure 5C). However, at 10 μM it produced a significant G0/G1 arrest and decreased the cellular populations in the S and G2/M phases ( Figure 5C,D). ...
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... did not cause any significant restriction of the cell cycle progression at 0.3 μM, 1 μM and 5 μM ( Figure 5C). However, at 10 μM it produced a significant G0/G1 arrest and decreased the cellular populations in the S and G2/M phases ( Figure 5C,D). These results agree with those formerly obtained by the MTT assay on HepG2 cells treated with the same CC1 concentrations for 24 h. ...
Citations
... MT participates in the storage, transport, and bioutilization of Zn, so a decreased expression of MT reduces the absorption efficiency of Zn in the body [36]. Moreover, MT2 is rich in reduced thiol groups (SH), which have a free radical scavenging capacity 100 times that of GSH, and can inhibit the release of mitochondrial cytochrome c and activate caspase-3 to reduce cell apoptosis and myocardial injury [37,38]. These were further confirmed by the present study where it was found that ZnLA administration increased the mRNA expression of ZNT-1, MT1A, and MT-2B and intracellular GSH-PX activity, but decreased LDH activity, cell apoptosis, and caspase-3 protein expression levels in IPEC-J2 cells. ...
Zinc lactate (ZnLA) is a new organic zinc salt which has antioxidant properties in mammals and can improve intestinal function. This study explored the effects of ZnLA and ZnSO4 on cell proliferation, Zn transport, antioxidant capacity, mitochondrial function, and their underlying molecular mechanisms in intestinal porcine epithelial cells (IPEC-J2). The results showed that addition of ZnLA promoted cell proliferation, inhibited cell apoptosis and IL-6 secretion, and upregulated the mRNA expression and concentration of MT-2B, ZNT-1, and CRIP, as well as affected the gene expression and activity of oxidation or antioxidant enzymes (e.g., CuZnSOD, CAT, and Gpx1, GSH-PX, LDH, and MDA), compared to ZnSO4 or control. Compared with the control, ZnLA treatment had no significant effect on mitochondrial membrane potential, whereas it markedly increased the mitochondrial basal OCR, nonmitochondrial respiratory capacity, and mitochondrial proton leakage and reduced spare respiratory capacity and mitochondrial reactive oxygen (ROS) production in IPEC-J2 cells. Furthermore, ZnLA treatment increased the protein expression of Nrf2 and phosphorylated AMPK, but reduced Keap1 and p62 protein expression and autophagy-related genes LC3B-1 and Beclin mRNA abundance. Under H2O2-induced oxidative stress conditions, ZnLA supplementation markedly reduced cell apoptosis and mitochondrial ROS levels in IPEC-J2 cells. Moreover, ZnLA administration increased the protein expression of Nrf2 and decreased the protein expression of caspase-3, Keap1, and p62 in H2O2-induced IPEC-J2 cells. In addition, when the activity of AMPK was inhibited by Compound C, ZnLA supplementation did not increase the protein expression of nuclear Nrf2, but when Compound C was removed, the activities of AMPK and Nfr2 were both increased by ZnLA treatment. Our results indicated that ZnLA could improve the antioxidant capacity and mitochondrial function in IPEC-J2 cells by activating the AMPK-Nrf2-p62 pathway under normal or oxidative stress conditions. Our novel finding also suggested that ZnLA, as a new feed additive for piglets, has the potential to be an alternative for ZnSO4.
1. Introduction
Zinc (Zn), one of the most important trace elements in mammals, has been reported to reduce the incidence of diarrhea and improve the structure and function of the intestinal barrier in postweaning piglets [1–4]. Extracellular and intracellular Zn²⁺ in mammalian cells play a key role in physiological or pathological processes, including growth, immunity, and nutrient metabolism [5]. Previous reports have confirmed that Zn deficiency in animals led to a decrease in the number of T cells [6], oxidative stress, intestinal dysfunction, and inflammatory cell infiltration [4, 7, 8]. Traditionally, inorganic Zn (oxides and sulfates) has served as a feed additive to promote growth performance in livestock. To date, Zn additives in the market are in various types, such as zinc oxide, zinc sulfate, and nanozinc, all of which have a benefit in Zn absorption and combating diarrhea [9–13]. However, the excessive use and low absorption efficiency of inorganic Zn in livestock and poultry breeding resulted in the deposition of heavy metals in animal products and the high production of excrement, which inevitably caused concerns in meat safety and environmental pollution [14, 15].
Zinc lactate (ZnLA) is chemically synthesized from feed-grade zinc oxide and DL-lactic acid and can easily bind with ligands or metal carriers in enterocytes, which plays a key role in antioxidant function and immune response in animals. Previous studies have reported that the relative bioavailability of ZnLA in animal production is higher than that of inorganic Zn and can improve the growth performance of animals [16]. For example, the addition of ZnLA to animal feed improved the utilization of serum free amino acids and meat quality (e.g., average shell strength and shell thickness) and reduced the shell-breaking rate in chickens [17, 18]. Dietary ZnLA supplementation could also increase the birth weight and weaning survival rate in rabbits, as well as enhance fur elasticity and brightness [19]. Recent reports have indicated that organic Zn in pigs is more helpful in adjusting the adaptive response to piglets’ oxidative stress compared with inorganic Zn [20]. However, the effect mechanisms of ZnLA on the antioxidant and anti-inflammatory ability in pigs have not been well-studied.
It is known that nuclear factor erythroid 2-related factor 2 (Nrf2), a principal key transcription factor, has been considered as the main stress regulator that activates the antioxidant system. Upon exposure to various stressors, the release of Nrf2 from Kelch-like ECH-associated protein 1 (Keap1) translocates into the nucleus, resulting in the expression of various cytoprotective genes [21]. Recent studies have reported that Nrf2 could be activated by AMP-activated protein kinase (AMPK) and modulate autophagy-related genes (e.g., p62, Beclin, and LC3B-1/2) to participate in the alleviation of oxidative stress in mammalian cells [22]. Autophagy-related protein p62 can inhibit Nrf2 degradation and promote Nrf2 stability and nuclear translocation by interfering with Keap1-Nrf2 interaction to participate in the cellular antioxidative stress response [23]. However, whether ZnLA could protect against oxidative stress by modulating AMPK-Nrf2 activation and autophagy signals is still poorly understood. Moreover, mitochondria are the main energy source of cells, where they play an important role in cell processes such as apoptosis, reactive oxygen species (ROS) generation, cell cycle, and thermogenesis. Oxidative damage leads to ROS production and mitochondrial dysfunction [24]. A previous study showed that the combination of Zn and selenium improved mitochondrial function and alleviated oxidative stress caused by Alzheimer’s disease [24]. Therefore, the purpose of this study was to compare the effects of ZnLA and ZnSO4 on cell proliferation and autophagy, Zn transport, antioxidant capacity, and mitochondrial function in intestinal porcine epithelial cells (IPEC-J2) and to reveal the associated regulatory mechanism of ZnLA in H2O2-induced oxidative stress in IPEC-J2 cells.
2. Materials and Methods
2.1. Cell Culture
The IPEC-J2 cells derived from the jejunal epithelia of the neonatal piglets were used in all studies to assess the related mechanisms in vitro. IPEC-J2 cells were grown in uncoated plastic culture flasks in Dulbecco’s Modified Eagle Medium (DMEM), 10% fetal calf serum (FBS; Hyclone, UT, USA), 5 mM L-glutamine, and 1% antibiotics (100 U/mL penicillin and 100 U/mL streptomycin) and cultured at 37°C with 5% CO2. The media was changed every two days, and the pH of all cell culture media was maintained at 7.4. The cells covered the bottom of the culture bottle and were trypsinized into a six-well plate and cultured at 37°C with 5% CO2. When cells were grown to 70-80% confluence, the cells were cultured in treatment mediums. The cells were then collected to determine the relevant indicators.
2.2. Cell Viability Assays
IPEC-J2 cells were seeded in a 96-well plate at a density of cells/well and grown to 80% confluence. Cells were treated with DMEM containing ZnLA (99%; Sichuan Zoology Feed Co. Ltd.) and ZnSO4 with final Zn concentrations of 0, 0.1, 0.5, 1, 2.5, 5, 7.5, 10, 15, and 20 mg/L. After incubation for 6, 12, 24, 36, 48, and 60 h, cell viability was evaluated by cell counting kits (CKK-8) (Dojindo, Kumamoto, Japan) using a microplate reader at 450 nm according to the manufacturer’s instructions.
2.3. Cell Treatment
At ~70-80% confluence, ZnLA or ZnSO4 was added to fresh medium without FBS, which contained the same amount of Zn (7.5 mg/L). In order to eliminate the interference of lactic acid, equal amounts of lactic acid and Zn compared with the ZnLA group were used. To induce oxidative stress, 200 μM H2O2 (Sigma-Aldrich, MO, USA) was used as previously reported [25]. Compound C (5 μM) (Selleck, Shanghai, China), an AMPK inhibitor, was added to the medium to inhibit AMPK activity.
2.4. Intracellular Enzymes and Inflammatory Cytokines
Harvested cells were extracted total proteins; then, cellular malondialdehyde (MDA), superoxide dismutase (SOD), lactic dehydrogenase (LDH), glutathione peroxidase (GSH-PX), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), cysteine-rich intestinal protein 1 (CRIP1), cysteine-rich intestinal protein 2 (CRIP2), and metallothionein 1A (MT1A) activities or levels were determined using ELISA kits (Wuhan Huamei Biotechnology Co. LTD) in accordance with the manufacturer’s protocols.
2.5. Cell Apoptosis Assay
Apoptosis analysis was performed with the Annexin V-FITC/PI (propidium iodide) flow cytometry kit. IPEC-J2 cells were seeded into 6-well plates at a density of cells/well. After treatment, 5 μL Annexin V-FITC for 15 min and 5 μL PI for 5 min at room according to the manufacturer’s instructions [26].
2.6. Cell Cycle Assay
Cell cycle progression was examined with a flow cytometer using propidium iodide (PI) staining. Briefly, IPEC-J2 cells were seeded into 6-well culture plates. After treatment, the cells were trypsinized and fixed with cold 70% ethanol at 4°C overnight. The cells were then rehydrated, washed twice with ice-cold PBS, and analyzed by PI staining. PI absorbance was determined by fluorescence-activated cell sorting on a flow cytometer (Beckman Coulter Inc., USA).
2.7. Mitochondrial ROS Measurement
Intracellular mitochondrial reactive oxygen (ROS) generation was evaluated using MitoSOX Red reagent (Invitrogen, Shanghai, China). IPEC-J2 cells were seeded into 6-well plates and then cultured in different treatments. Cells were treated with 5 μM MitoSOX Red reagent at 37°C for 10 min in the dark. Then, the fluorescence intensity of 12,000 cells was assayed using a Beckman MoFlo XDP flow cytometer (Beckman Coulter Inc., CA, USA).
2.8. Mitochondrial Membrane Potential (MMP) Measurement
Mitochondrial depolarization in the early stages of apoptosis was evaluated using JC-1 reagent (Invitrogen) by double fluorescence staining. The loss of MMP was indicated by a decrease in the red/green mean fluorescence intensity ratio. IPEC-J2 cells were seeded into confocal dishes and then treated under different conditions. JC-1 (10 μg/mL) was added to the medium for 30 min in the dark and then the cells were washed twice with PBS. Cells in the confocal dishes were treated with an antifluorescence quenching agent and observed using a Zeiss LSM880 confocal microscope as previously described [26].
2.9. Mitochondrial Respiration Metabolism Assays
Mitochondrial respiration was measured using the XF-24 Extracellular Flux Analyzer and a Cell Mito Stress Test Kit (Agilent Technologies, Inc., CA, USA) in accordance with the manufacturer’s instructions. Non-ATP-linked oxygen consumption (proton leak), ATP-linked mitochondrial oxygen consumption (ATP production), and maximal respiration capacity were estimated. Baseline oxygen consumption rate (OCR) minus the maximal respiratory capacity represented the spare respiratory capacity. Residual oxygen consumption after the addition of rotenone and antimycin A was due to nonmitochondrial respiration and was subtracted from all measured values in the analysis. Total cellular protein concentration was determined with a BCA assay kit to normalize mitochondrial respiration rates [27].
2.10. Real-Time Quantitative Polymerase Chain Reaction
The expression of mRNA was measured by real-time quantitative PCR. Total RNA was extracted from samples of IPEC-J2 cells using TRIzol reagent (Invitrogen) and reverse transcribed into cDNA using the Prime Script RT reagent kit (TaKaRa Bio, Otsu, Japan). Quantitative PCR was performed using SYBR Premix Ex Taq (TaKaRa Bio, Japan). The reaction was performed at a total volume of 10 μL, with the assay solution containing 5 μL SYBR Green mix (TaKaRa Bio, Japan), 0.2 μL ROX internal reference dye, 3.4 μL deionized H2O, 1 μL cDNA template, and 0.2 μL each of the forward and reverse primers. The expression of the housekeeping gene β-actin was used to normalize the expression levels. The primers were designed to flank introns using the Primer 5 software. The primer sequences are listed in the supplemental Table 1.
2.11. Protein Qualification by the Wes Simple Western System and Western Blot
The process of protein quantification was performed using the Wes Simple Western System (ProteinSimple, San Jose, CA, USA) or the Western Blot technique as previous described [25, 26]. The antibodies used in the study included nuclear factor erythroid 2-related factor 2 (Nrf2) (Abcam, Cambridge, MA, USA), β-actin (Abcam), Kelch-like ECH-associated protein 1 (Keap1) (Abcam), AMP-activated protein kinase (AMPK) (Abcam), phosphorylated AMPK (Abcam), lamin B (Abcam), and p62 (Abcam). The mouse β-actin antibody was used as a loading control for total protein, while nuclear Nrf2 protein expression was normalized to lamin B. All protein concentrations were determined using a standard BCA protein assay. Results of Wes Simple Western System were obtained using the “gel view” function of the Protein Simple software (ProteinSimple). Western blot data were quantified using the ImageJ software.
2.12. Immunofluorescence Assay
IPEC-J2 cells ( cells per well) were seeded into confocal dishes and treated with different conditions. Cells were fixed with 4% paraformaldehyde for 20 min and permeabilized with Triton X-100 (0.3%) for 10 min. Then, cells were blocked with bovine serum albumin (1%) for 30 min and were incubated overnight with Nrf2, caspase-3, or Keap1 antibodies diluted at 1 : 100 at 4°C. Cells were washed with cold PBS three times, and then incubated with secondary antibody for 1 h. Nuclear DNA was labeled with 4,6-diamidino-2-phenylindole (DAPI) for 2 minutes. The fluorescence images were captured using a Zeiss LSM880 confocal microscope and analyzed with the ZEN software.
2.13. Statistical Analysis
Statistical analysis was analyzed through one-way ANOVA or -test using the SPSS 19.0 software. All the data were presented as (SEM). values below 0.05 were considered statistically significant.
3. Results
3.1. Effects of ZnLA Supplementation on Cell Viability, Cell Cycle, and Apoptosis
To determine the effects of different Zn sources on cell proliferation in IPEC-J2 cells, we exposed IPEC-J2 cells to increasing concentrations of ZnLA or ZnSO4 for 6, 12, 24, 36 48, or 60 h, respectively (Figures 1(a) and 1(b)). We found that exposure to 7.5 mg/L Zn for 12 h significantly increased cell viability compared with other treatments (). Thus, the concentrations of 7.5 mg/L Zn from ZnLA or ZnSO4 for 12 h were selected as suitable conditions for the subsequent experiments. As shown in Figures 1(c) and 1(d), the G1 phase of the cell cycle was markedly decreased in the ZnLA group compared with the control group (). However, ZnLA administration was increased in the S phase () and G2/M phase (). In addition, we found that the proportion of early and late apoptotic cells treated with ZnLA was the lowest compared to the other three groups (Figure 1(e)). These results suggested that ZnLA could reduce cell apoptosis and promote cell proliferation.
(a)
... In fact, crambescidins have been widely biological investigated, while there are not many biological reports on crambescins. Thus, Botana and co-workers cytotoxically examined crambescins A1 (60) and C1 (66) against human hepatoblastoma cell HepG2, including mechanistic studies, such as proliferation, apoptosis, and antioxidant activities [33]. The results revealed that 66 was able to induce MTs (metallothioneins) transcription and synthesis in HepG2 cell lines, protecting cells from oxidative damage at concentrations that retained cell viability. ...
Marine organisms are prolific resources of guanidine-containing natural products with intriguing structures and promising biological activities. These molecules have therefore attracted the attention of chemists and biologists for their further studies towards potential drug leads. This review focused on the guanidine alkaloids derived from marine sources and discussed the recent progress on their isolation, synthesis and biological activities, covering the literature from the year 2010 to the present.
... 693) showed that the former protects against cytotoxic oxidative damage by induction of metallothionein, while the latter is ineffective. 694 The bastadin-class of bromotyrosine compounds, in particular bastadin-6, 695 suppress foam formation in macrophages via inhibition of cholesterol-ester formation, and may have application in the treatment of artherosclerosis. 696 Panicein A hydroquinone 697 (Haliclona mucosa) inhibits the efflux of doxorubicin by the Hedgehog receptor Patched and enhances the anticancer efficacy of the drug. ...
Covering: 2015. Previous review: Nat. Prod. Rep., 2016, 33, 382-431This review covers the literature published in 2015 for marine natural products (MNPs), with 1220 citations (792 for the period January to December 2015) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1340 in 429 papers for 2015), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.
... Intracellular antioxidants commonly include glutathione (GSH), heme oxygenase-1 (HO-1), superoxide dismutase-1 and triphosphopyridine nucleotide (NAPDH) [46]. MT2A could create a new pool of thiol in cell cytosol which could attenuate the damaging effect of GSH depletors [47]. The ability of MT2A to scavenge free • OH and peroxyl radicals is found to be 100-fold higher than that of GSH [48]. ...
... A wide range of adverse stimuli, such as oxidative stress could cause cell apoptosis [21]. MT2A reduces adriamycin-induced myocardial injury through inhibition of oxidative stress-mediated mitochondrial cytochrome-c release and activated caspase-3 [47], protects human umbilical vein endothelial cells from lipopolysaccharide (LPS)-associated apoptosis, and also influences cellular behaviors such as proliferation and chemotaxis by binding to membrane receptors [52]. MT2A could also protect endoplasmic reticulum (ER) stress-induced cardiac failure associated with attenuation of myocardial apoptosis [53]. ...
Mammalian metallothionein-2A (MT2A) has received considerable attention in recent years due to its crucial pathophysiological role in anti-oxidant, anti-apoptosis, detoxification and anti-inflammation. For many years, most studies evaluating the effects of MT2A have focused on reactive oxygen species (ROS), as second messengers that lead to oxidative stress injury of cells and tissues. Recent studies have highlighted that oxidative stress could activate mitogen-activated protein kinases (MAPKs), and MT2A, as a mediator of MAPKs, to regulate the pathogenesis of various diseases. However, the molecule mechanism of MT2A remains elusive. A deeper understanding of the functional, biochemical and molecular characteristics of MT2A would be identified, in order to bring new opportunities for oxidative stress therapy.
Zinc metabolism at the cellular level is critical for many biological processes in the body. A key observation is the disruption of cellular homeostasis, often coinciding with disease progression. As an essential factor in maintaining cellular equilibrium, cellular zinc has been increasingly spotlighted in the context of disease development. Extensive research suggests zinc’s involvement in promoting malignancy and invasion in cancer cells, despite its low tissue concentration. This has led to a growing body of literature investigating zinc’s cellular metabolism, particularly the functions of zinc transporters and storage mechanisms during cancer progression. Zinc transportation is under the control of two major transporter families: SLC30 (ZnT) for the excretion of zinc and SLC39 (ZIP) for the zinc intake. Additionally, the storage of this essential element is predominantly mediated by metallothioneins (MTs). This review consolidates knowledge on the critical functions of cellular zinc signaling and underscores potential molecular pathways linking zinc metabolism to disease progression, with a special focus on cancer. We also compile a summary of clinical trials involving zinc ions. Given the main localization of zinc transporters at the cell membrane, the potential for targeted therapies, including small molecules and monoclonal antibodies, offers promising avenues for future exploration.
Crambescins are guanidine alkaloids from the sponge Crambe crambe. Crambescin C1 (CC) induces metallothionein genes and nitric oxide (NO) is one of the triggers. We studied and compared the in vitro, in vivo, and in silico effects of some crambescine A and C analogs. HepG2 gene expression was analyzed using microarrays. Vasodilation was studied in rat aortic rings. In vivo hypotensive effect was directly measured in anesthetized rats. The targets of crambescines were studied in silico. CC and homo-crambescine C1 (HCC), but not crambescine A1 (CA), induced metallothioneins transcripts. CC increased NO production in HepG2 cells. In isolated rat aortic rings, CC and HCC induced an endothelium-dependent relaxation related to eNOS activation and an endothelium-independent relaxation related to iNOS activation, hence both compounds increase NO and reduce vascular tone. In silico analysis also points to eNOS and iNOS as targets of Crambescin C1 and source of NO increment. CC effect is mediated through crambescin binding to the active site of eNOS and iNOS. CC docking studies in iNOS and eNOS active site revealed hydrogen bonding of the hydroxylated chain with residues Glu377 and Glu361, involved in the substrate recognition, and explains its higher binding affinity than CA. The later interaction and the extra polar contacts with its pyrimidine moiety, absent in the endogenous substrate, explain its role as exogenous substrate of NOSs and NO production. Our results suggest that CC serve as a basis to develop new useful drugs when bioavailability of NO is perturbed.
La régulation de la mort cellulaire est cruciale pour les êtres vivants. La mort cellulaire programmée (PCD) peut être déclenchée par des signaux extra- ou intracellulaires dans des conditions physiologiques (cette programmation permet par exemple le maintien de l’homéostasie tissulaire et un développement optimal) ou pathologiques afin d’éliminer des cellules altérées ou en prolifération anarchique. Une dérégulation de la mort cellulaire programmée est impliquée dans diverses pathologies humaines telles que les cancers, les maladies neurodégénératives et les maladies inflammatoires. La découverte de modulateurs de la mort cellulaire ouvre sur des perspectives prometteuses notamment en thérapie anticancéreuse, mais également en recherche fondamentale, pour améliorer notre compréhension des régulations moléculaires mises en jeu. Dans le cadre de cette thèse, des molécules marines (pigments marins et métabolites purifiés à partir d’éponges, notamment Crambe tailliezi et Crambe crambe, issues de la Mer Méditerranée et de l’Océan Atlantique) ont été utilisées afin d’inhiber, ou de déclencher, des voies de mort cellulaire non canoniques. Ces travaux ont été notamment focalisés sur l’étude d’un métabolite de haut poids moléculaire purifié à partir de l’éponge Crambe tailliezi, appelé P3 (2200-2800 Da). Celui-ci est cytotoxique et induit une mort apoptotique des cellules d’ostéosarcome U-2 OS qui ne dépend pas des caspases mais qui est sensible à la molécule necrostatine-1. Ce métabolite induit également une inhibition spécifique des protéines kinases mitotiques Aurora A et B. Ces résultats, tout en soulignant l’importance d’étudier la chimiodiversité marine, ouvrent de nouvelles perspectives en recherche fondamentale et appliquée.
Here we implement a novel asymmetric Biginelli reaction strategy to achieve enantiospecific total synthesis of (+)-crambescin A in only 8 steps from the abundant and inexpensive aliphatic aldehyde, urea and methyl 3-oxobutanoate.
Reactive oxygen and nitrogen species (ROS and RNS, respectively) are byproducts of cellular physiological processes of the metabolism of intermediary nutrients. Although physiological defense mechanisms readily convert these species into water or urea, an improper balance between their production and removal leads to oxidative stress (OS), which is harmful to cellular components. This OS may result in uncontrolled growth or, ultimately, cell death. In addition, ROS and RNS are closely related to the development of diabetes and its complications. Therefore, numerous researchers have proposed the development of strategies for the removal of ROS/RNS to prevent or treat diabetes and its complications. Some molecules that are synthesized in the body or obtained from food participate in the removal and neutralization of ROS and RNS. Metallothionein, a cysteine‐rich protein, is a metal‐binding protein that has a wide range of functions in cellular homeostasis and immunity. Metallothionein can be induced by a variety of conditions, including zinc supplementation, and plays a crucial role in mediating anti‐OS, anti‐apoptotic, detoxification, and anti‐inflammatory effects. Metallothionein can modulate various stress‐induced signaling pathways (mitogen‐activated protein kinase, Wnt, nuclear factor‐κB, phosphatidylinositol 3‐kinase, sirtuin 1/AMP‐activated protein kinase and fibroblast growth factor 21) to alleviate diabetes and diabetic complications. However, a deeper understanding of the functional, biochemical, and molecular characteristics of metallothionein is needed to bring about new opportunities for OS therapy. This review focuses on newly proposed functions of a metallothionein and their implications relevant to diabetes and its complications.
