Bone marrow mesenchymal stem cell transplantation retards the natural senescence of rat hearts

Enhancing Oocyte Quality in Aging Mice: Insights from Mesenchymal Stem Cell Therapy and FOXO3a Signaling Pathway Activation

Ovarian aging reduced the quality of oocytes, resulting in age-related female infertility. It is reported that mesenchymal stem cells (MSCs) therapy can improve age-related ovarian function decline and the success rate of in vitro maturation (IVM) in assisted reproductive therapy. In order to investigate the effectiveness and mechanisms of MSCs to enhance oocyte quality of cumulus oocyte complexes (COCs) in advanced age, this study focus on the respective functional improvement of oocytes and granulosa cells (GCs) from aging mice and further to explore and verify the possible mechanisms. Here, we studied a popular but significant protein of follicular development, Forkhead box O-3a (FOXO3a), which is a transcription factor that mediates a variety of cellular processes, but the functions of which in regulating oocyte quality in MSCs therapy still remain inconclusive. In this study, the RNA-seq data of metaphase II (MII) oocytes and GCs isolated from COCs confirmed that, GCs of immature follicles show the most potential to be the targeted cells of bone marrow mesenchymal stem cells (BMSCs) by FOXO3a signaling pathway. Furthermore, we demonstrated the effectiveness of BMSCs co-culture with aging COCs to enhance oocyte quality and found its mechanism to function via ameliorating the biological function of GCs by alleviating FOXO3a levels. These results provide significant fundamental research on MSCs therapy on ovarian aging, as well as offering guidance for raising the success rate of assisted reproductive technology such IVM in clinical and non-clinical settings.

Dental pulp stem cells ameliorate D-galactose-induced cardiac ageing in rats

Background

Ageing is a key risk factor for cardiovascular disease and is linked to several alterations in cardiac structure and function, including left ventricular hypertrophy and increased cardiomyocyte volume, as well as a decline in the number of cardiomyocytes and ventricular dysfunction, emphasizing the pathological impacts of cardiomyocyte ageing. Dental pulp stem cells (DPSCs) are promising as a cellular therapeutic source due to their minimally invasive surgical approach and remarkable proliferative ability.

Aim

This study is the first to investigate the outcomes of the systemic transplantation of DPSCs in a D-galactose (D-gal)-induced rat model of cardiac ageing. Methods. Thirty 9-week-old Sprague-Dawley male rats were randomly assigned into three groups: control, ageing (D-gal), and transplanted groups (D-gal + DPSCs). D-gal (300 mg/kg/day) was administered intraperitoneally daily for 8 weeks. The rats in the transplantation group were intravenously injected with DPSCs at a dose of 1 × 106 once every 2 weeks.

Results

The transplanted cells migrated to the heart, differentiated into cardiomyocytes, improved cardiac function, upregulated Sirt1 expression, exerted antioxidative effects, modulated connexin-43 expression, attenuated cardiac histopathological alterations, and had anti-senescent and anti-apoptotic effects.

Conclusion

Our results reveal the beneficial effects of DPSC transplantation in a cardiac ageing rat model, suggesting their potential as a viable cell therapy for ageing hearts.

Endogenous sulfur dioxide deficiency as a driver of cardiomyocyte senescence through abolishing sulphenylation of STAT3 at cysteine 259

OBJECTIVE

Cardiomyocyte senescence is an important contributor to cardiovascular diseases and can be induced by stressors including DNA damage, oxidative stress, mitochondrial dysfunction, epigenetic regulation, etc. However, the underlying mechanisms for the development of cardiomyocyte senescence remain largely unknown. Sulfur dioxide (SO2) is produced endogenously by aspartate aminotransferase 2 (AAT2) catalysis and plays an important regulatory role in the development of cardiovascular diseases. The present study aimed to explore the effect of endogenous SO2 on cardiomyocyte senescence and the underlying molecular mechanisms.

APPROACH AND RESULTS

We interestingly found a substantial reduction in the expression of AAT2 in the heart of aged mice in comparison to young mice. AAT2-knockdowned cardiomyocytes exhibited reduced SO2 content, elevated expression levels of Tp53, p21Cip/Waf, and p16INk4a, enhanced SA-β-Gal activity, and elevated level of γ-H2AX foci. Notably, supplementation with a SO2 donor ameliorated the spontaneous senescence phenotype and DNA damage caused by AAT2 deficiency in cardiomyocytes. Mechanistically, AAT2 deficiency suppressed the sulphenylation of signal transducer and activator of transcription 3 (STAT3) facilitated its nuclear translocation and DNA-binding capacity. Conversely, a mutation in the cysteine (Cys) 259 residue of STAT3 blocked SO2-induced STAT3 sulphenylation and subsequently prevented the inhibitory effect of SO2 on STAT3-DNA-binding capacity, DNA damage, and cardiomyocyte senescence. Additionally, cardiomyocyte (cm)-specific AAT2 knockout (AAT2cmKO) mice exhibited a deterioration in cardiac function, cardiomegaly, and cardiac aging, whereas supplementation with SO2 donors mitigated the cardiac aging and remodeling phenotypes in AAT2cmKO mice.

CONCLUSION

Downregulation of the endogenous SO2/AAT2 pathway is a crucial pathogenic mechanism underlying cardiomyocyte senescence. Endogenous SO2 modifies STAT3 by sulphenylating Cys259, leading to the inhibition of DNA damage and the protection against cardiomyocyte senescence.

Cellular senescence in reproduction: a two-edged sword†

Cellular senescence (CS) is the state when cells are no longer capable to divide even after stimulation with grown factors. Cells that begin to undergo CS stop in the cell cycle and enter a suspended state without committing to programmed cell death. These cells assume a specific phenotype and influence their microenvironment by secreting molecules and extracellular vesicles that are part of the so-called senescent cell-associated secretory phenotype (SASP). Cellular senescence is intertwined with physiological and pathological conditions in the human organism. In terms of reproduction, senescent cells are present from reproductive tissues and germ cells to gestational tissues, and participate from fertilization to delivery, going through adverse reproductive outcomes such as pregnancy losses. Furthermore, various SASP molecules are enriched in gestational tissues throughout pregnancy. Thus, the aim of this review is to provide a basis about the features and potential roles played by CS throughout the reproductive process, encompassing its implication in each step of it and proposing a way to manage it in adverse reproductive contexts.

The Potential of Mesenchymal Stem/Stromal Cell Therapy in Mustard Keratopathy: Discovering New Roads to Combat Cellular Senescence

Mesenchymal stem/stromal cells (MSCs) are considered a valuable option to treat ocular surface disorders such as mustard keratopathy (MK). MK often leads to vision impairment due to corneal opacification and neovascularization and cellular senescence seems to have a role in its pathophysiology. Herein, we utilized intrastromal MSC injections to treat MK. Thirty-two mice were divided into four groups based on the exposure to 20 mM or 40 mM concentrations of mustard and receiving the treatment or not. Mice were clinically and histopathologically examined. Histopathological evaluations were completed after the euthanasia of mice after four months and included hematoxylin and eosin (H&E), CK12, and beta-galactosidase (β-gal) staining. The treatment group demonstrated reduced opacity compared to the control group. While corneal neovascularization did not display significant variations between the groups, the control group did register higher numerical values. Histopathologically, reduced CK12 staining was detected in the control group. Additionally, β-gal staining areas were notably lower in the treatment group. Although the treated groups showed lower severity of fibrosis compared to the control groups, statistical difference was not significant. In conclusion, it seems that delivery of MSCs in MK has exhibited promising therapeutic results, notably in reducing corneal opacity. Furthermore, the significant reduction in the β-galactosidase staining area may point towards the promising anti-senescence potential of MSCs.

Senescence and senotherapies in biliary atresia and biliary cirrhosis

BACKGROUND

Premature senescence occurs in adult hepatobiliary diseases and worsens the prognosis through deleterious liver remodeling and hepatic dysfunction. Senescence might also arises in biliary atresia (BA), the first cause of pediatric liver transplantation. Since alternatives to transplantation are needed, our aim was to investigate premature senescence in BA and to assess senotherapies in a preclinical model of biliary cirrhosis.

METHODS

BA liver tissues were prospectively obtained at hepatoportoenterostomy (n=5) and liver transplantation (n=30) and compared to controls (n=10). Senescence was investigated through spatial whole transcriptome analysis, SA-β-gal activity, p16 and p21 expression, γ-H2AX and senescence-associated secretory phenotype (SASP). Human allogenic liver-derived progenitor cells (HALPC) or dasatinib and quercetin (D+Q) were administrated to two-month-old Wistar rats after bile duct ligation (BDL).

RESULTS

Advanced premature senescence was evidenced in BA livers from early stage and continued to progress until liver transplantation. Senescence and SASP were predominant in cholangiocytes, but also present in surrounding hepatocytes. HALPC but not D+Q reduced the early marker of senescence p21 in BDL rats and improved biliary injury (serum γGT and Sox9 expression) and hepatocytes mass loss (Hnf4a).

CONCLUSIONS

BA livers displayed advanced cellular senescence at diagnosis that continued to progress until liver transplantation. HALPC reduced early senescence and improved liver disease in a preclinical model of BA, providing encouraging preliminary results regarding the use of senotherapies in pediatric biliary cirrhosis.

The Prescription of Oral Mucosal Mesenchymal Stem Cells post-Traumatic Brain Injury Improved the Kidney and Heart Inflammation and Oxidative Stress

Background

In the last years, mesenchymal stem cells (MSCs) have been considered as a useful strategy to treat many diseases such as traumatic brain injury (TBI). The production of inflammatory agents by TBI elicits an inflammatory response directed to other systems of body, such as the heart and the kidneys. In this study, the efficacy of oral mucosal mesenchymal stem cells (OMSCs) prescription after TBI in inflammation and oxidative stress of the heart and kidneys was evaluated.

Methods

Twenty-four male rats were located in groups as follows: sham, TBI, vehicle (Veh), and stem cell (SC). OMSCs were injected intravenously 1 and 24 hours after TBI. Inflammatory, oxidative stress, and histopathological outcomes of the heart and kidney tissues were investigated 48 hours after TBI.

Results

TBI caused an increase in the level of interleukin-1β (IL-1β), interleukin-6 (IL-6), malondialdehyde (MDA), and carbonyl protein (PC) of the heart and kidney compared to the sham group. Superoxide dismutase (SOD), total antioxidant capacity (TAC), catalase (CAT), and interleukin-10 (IL-10) of the heart and kidney decreased after TBI. The use of OMSCs after TBI reduced the changes of these factors in both the heart and the kidney.

Conclusion

Application of OMSCs after TBI can decrease inflammation and oxidative stress of the heart and kidney tissues leading to the reduction of damage. Therefore, this method can be evaluated in the TBI patients in future studies.

Cellular senescence: the good, the bad and the unknown

Cellular senescence is a ubiquitous process with roles in tissue remodelling, including wound repair and embryogenesis. However, prolonged senescence can be maladaptive, leading to cancer development and age-related diseases. Cellular senescence involves cell-cycle arrest and the release of inflammatory cytokines with autocrine, paracrine and endocrine activities. Senescent cells also exhibit morphological alterations, including flattened cell bodies, vacuolization and granularity in the cytoplasm and abnormal organelles. Several biomarkers of cellular senescence have been identified, including SA-βgal, p16 and p21; however, few markers have high sensitivity and specificity. In addition to driving ageing, senescence of immune and parenchymal cells contributes to the development of a variety of diseases and metabolic disorders. In the kidney, senescence might have beneficial roles during development and recovery from injury, but can also contribute to the progression of acute kidney injury and chronic kidney disease. Therapies that target senescence, including senolytic and senomorphic drugs, stem cell therapies and other interventions, have been shown to extend lifespan and reduce tissue injury in various animal models. Early clinical trials confirm that senotherapeutic approaches could be beneficial in human disease. However, larger clinical trials are needed to translate these approaches to patient care.

Bone Marrow Mesenchymal Stem Cell Exosome Attenuates Inflammasome-Related Pyroptosis via Delivering circ_003564 to Improve the Recovery of Spinal Cord Injury

Bone marrow mesenchymal stem cell (BMSC) is previously reported to present a certain effect on treating spinal cord injury (SCI), while the underlying mechanism is largely uncovered. Therefore, the current study aimed to investigate the involvement of exosome-delivered circRNA profile in the BMSC's effect on pyroptosis for SCI treatment. H₂O₂ treated rat primary neurons were cultured with normal medium, BMSC, BMSC plus GW4869, and BMSC-derived exosome, respectively, then inflammasome-related pyroptosis markers, and circRNA profiles were detected. Subsequently, circ_003564-knockdown BMSC exosome was transfected into H₂O₂ treated rat primary neurons and NGF-stimulated PC-12 cells. Furthermore, in vivo validation was conducted. BMSC and BMSC-derived exosome both decreased inflammasome-related pyroptosis markers including cleaved caspase-1, GSDMD, NLRP3, IL-1β, and IL-18 in H₂O₂-treated neurons, while exosome-free BMSC (BMSC plus GW4869) did not obviously reduce these factors. Microarray assay revealed that BMSC (vs. exosome-free BMSC) and BMSC-derived exosome (vs. normal medium) greatly regulated circRNA profiles, which were enriched in neuroinflammation pathways (such as neurotrophin, apoptosis, and TNF). Among three functional candidate circRNAs (circ_015525, circ_008876, and circ_003564), circ_003564 was most effective to regulate inflammasome-related pyroptosis. Interestingly, circ_003564-knockdown BMSC exosome showed higher expression of inflammasome-related pyroptosis markers compared to negative-control-knockdown BMSC exosome in H₂O₂ treated primary neurons/NGF-stimulated PC-12 cells. In vivo, BMSC exosome improved the function recovery and decreased tissue injury and inflammasome-related pyroptosis in SCI rats, whose effect was attenuated by circ_003564 knockdown transfection. BMSC exosome attenuates inflammasome-related pyroptosis via delivering circ_003564, contributing to its treatment efficacy for SCI.

The role of cellular senescence in cardiac disease: basic biology and clinical relevance

Cellular senescence, classically defined as stable cell cycle arrest, is implicated in biological processes such as embryogenesis, wound healing and ageing. Senescent cells have a complex senescence-associated secretory phenotype (SASP), involving a range of pro-inflammatory factors with important paracrine and autocrine effects on cell and tissue biology. Clinical evidence and experimental studies link cellular senescence, senescent cell accumulation, and the production and release of SASP components with age-related cardiac pathologies such as heart failure, myocardial ischaemia and infarction, and cancer chemotherapy-related cardiotoxicity. However, the precise role of senescent cells in these conditions is unclear and, in some instances, both detrimental and beneficial effects have been reported. The involvement of cellular senescence in other important entities, such as cardiac arrhythmias and remodelling, is poorly understood. In this Review, we summarize the basic biology of cellular senescence and discuss what is known about the role of cellular senescence and the SASP in heart disease. We then consider the various approaches that are being developed to prevent the accumulation of senescent cells and their consequences. Many of these strategies are applicable in vivo and some are being investigated for non-cardiac indications in clinical trials. We end by considering important knowledge gaps, directions for future research and the potential implications for improving the management of patients with heart disease.

The functional mechanism of bone marrow-derived mesenchymal stem cells in the treatment of animal models with Alzheimer's disease: crosstalk between autophagy and apoptosis

The transplantation of bone marrow-derived mesenchymal stem cells (BMMSCs) alleviates neuropathology and improves cognitive deficits in animal models with Alzheimer's disease. However, the underlying mechanism remains undefined. Based on meta-analysis and comprehensive review, high-profile studies support the theory that transplanted BMMSCs activate autophagy, as evidenced by the expression levels of signal molecules such as Beclin-1, Atg5, LC3-II, and mTOR. Functional autophagy mitigates neuronal apoptosis, which is reflected by the alterations of IAPs, Bcl-2, caspase-3, and so forth. Moreover, the transplantation of BMMSCs can decrease aberrant amyloid-beta peptides as well as tau aggregates, inhibit neuroinflammation, and stimulate synaptogenesis. There is a signal crosstalk between autophagy and apoptosis, which may be regulated to produce synergistic effect on the preconditioning of stem cells. Forasmuch, the therapeutic effect of transplanted BMMSCs can be enhanced by autophagy and/or apoptosis modulators.

Characterization of transcriptional landscape in bone marrow-derived mesenchymal stromal cells treated with aspirin by RNA-seq

INTRODUCTION

Aspirin is a common antipyretic, analgesic, and anti-inflammatory drug, which has been reported to extend life in animal models and application in the treatment of aging-related diseases. However, it remains unclear about the effects of aspirin on bone marrow-derived mesenchymal stromal cells (BM-MSCs). Here, we aimed to analyze the influence of aspirin on senescence and young BM-MSCs.

METHODS

BM-MSCs were serially passaged to construct a replicative senescence model. SA-β-gal staining, PCR, western blot, and RNA-sequencing were performed on BM-MSCs with or without aspirin treatment, to examine aspirin's impact on bone marrow-derived mesenchymal stem cells.

RESULTS

SA-β-gal staining, PCR, and western blot revealed that aspirin could alleviate the cellular expression of senescence-related indicators of BM-MSCs, including a decrease of SA-β-gal-positive cells and staining intensity, and downregulation of p16, p21, and p53 expression after aspirin treatment. RNA-sequencing results shown in the biological processes related to aging, aspirin could influence cellular immune response and lipid metabolism.

CONCLUSION

The efficacy of aspirin for retarding senescence of BM-MSCs was demonstrated. Our study indicated that the mechanisms of this delay might involve influencing immune response and lipid metabolism.

LncRNA Malat-1 From MSCs-Derived Extracellular Vesicles Suppresses Inflammation and Cartilage Degradation in Osteoarthritis

Purpose: Extracellular Vesicles (EVs) derived from hMSCs, have the potential to alleviate cartilage damage and inflammation. We aimed to explore the effects of EVs derived from lncRNA malat‐1-overexpressing human mesenchymal stem cells (hMSCs) on chondrocytes.

Material and Methods: hMSCs-derived Extracellular Vesicles (hMSCs-EVs) were identified by transmission electron microscopy and western blot. We used a Sprague-Dawley (SD) rat model of CollagenaseⅡ-induced osteoarthritis (OA) as well as IL-1β-induced OA chondrocytes. Lentiviral vectors were used to overexpress lncRNA malat‐1 in hMSCs. Chondrocyte proliferation, inflammation, extracellular matrix degradation, and cell migration were measured by Edu staining, ELISA, western blot analysis, and transwell assay. Chondrocyte apoptosis was evaluated by flow cytometry, Hoechst 33342/PI Staining, and western blot. Safranine O-fast green (S-O) staining and HE staining were used to assess morphologic alterations of the rat knee joint.

Results: hMSCs^malat−1-EVs decreased MMP-13, IL-6, and Caspase-3 expression in IL-1β-induced OA chondrocytes. Moreover, hMSCs^malat−1-EVs promoted chondrocyte proliferation and migration, suppressed apoptosis, and attenuated IL-1β-induced chondrocyte injury. Our animal experiments suggested that hMSCs^malat−1-EVs were sufficient to prevent cartilage degeneration.

Conclusion: Our findings show that lncRNA malat-1from hMSCs‐delivered EVs can promote chondrocyte proliferation, alleviate chondrocyte inflammation and cartilage degeneration, and enhance chondrocyte repair. Overall, hMSCs^malat−1-EVs might be a new potential therapeutic option for patients with OA.

Exosomes Isolated From Bone Marrow Mesenchymal Stem Cells Exert a Protective Effect on Osteoarthritis via lncRNA LYRM4-AS1-GRPR-miR-6515-5p

Objectives

The aim of this study was to investigate the effects of exosomes isolated from human bone marrow mesenchymal stem cells (BMSCs) on osteoarthritis (OA) and a competitive endogenous RNA (ceRNA) network.

Methods

Exosomes were isolated from human BMSCs and characterized by transmission electron microscopy (TEM), Nanosight (NTA), and western blotting. Chondrocytes were treated with interleukin-1β (IL-1β) and then transfected with exosomes. Cell viability and apoptosis were determined using Cell Counting Kit-8 (CCK-8) and flow cytometry, respectively. Cells with IL-1β and exosomes were sequenced, and differentially expressed lncRNAs (DE-lncRNAs) and miRNAs (DE-miRNAs) were identified. Thereafter, a ceRNA network (LYRM4-AS1-GRPR-miR-6515-5p) was chosen for further validation.

Results

TEM, NTA, and western blotting showed that exosomes were successfully isolated, and PKH67 staining showed that exosomes could be taken up by IL-1β-induced chondrocytes. Compared with the control group, IL-1β significantly decreased cell viability and promoted apoptosis (P < 0.05), while exosomes reversed the changes induced by IL-1β. For MMP3, AKT, and GRPR, IL-1β upregulated their expression, while exosomes downregulated their expression. For PTEN, there was no significant difference in PTEN expression between the control and IL-1β groups; however, exosomes markedly upregulated PTEN expression. By sequencing, 907 DE-lncRNAs and 25 DE-miRNAs were identified, and a ceRNA network was constructed. The dual-luciferase reporter gene indicated that LYRM4-AS1, miR-6515-5, and GRPR interacted with each other. The results of cell experiments showed that LYRM4-AS1 regulated the growth of IL-1β-induced chondrocytes by GRPR/miR-6515-5p.

Conclusion

Exosomes may alleviate OA inflammation by regulating the LYRM4-AS1/GRPR/miR-6515-5p signaling pathway.

Human Wharton's Jelly-Derived Mesenchymal Stem Cells Minimally Improve the Growth Kinetics and Cardiomyocyte Differentiation of Aged Murine Cardiac c-kit Cells in In Vitro without Rejuvenating Effect

Cardiac c-kit cells show promise in regenerating an injured heart. While heart disease commonly affects elderly patients, it is unclear if autologous cardiac c-kit cells are functionally competent and applicable to these patients. This study characterised cardiac c-kit cells (CCs) from aged mice and studied the effects of human Wharton’s Jelly-derived mesenchymal stem cells (MSCs) on the growth kinetics and cardiac differentiation of aged CCs in vitro. CCs were isolated from 4-week- and 18-month-old C57/BL6N mice and were directly co-cultured with MSCs or separated by transwell insert. Clonogenically expanded aged CCs showed comparable telomere length to young CCs. However, these cells showed lower Gata4, Nkx2.5, and Sox2 gene expressions, with changes of 2.4, 3767.0, and 4.9 folds, respectively. Direct co-culture of both cells increased aged CC migration, which repopulated 54.6 ± 4.4% of the gap area as compared to aged CCs with MSCs in transwell (42.9 ± 2.6%) and CCs without MSCs (44.7 ± 2.5%). Both direct and transwell co-culture improved proliferation in aged CCs by 15.0% and 16.4%, respectively, as traced using carboxyfluorescein succinimidyl ester (CFSE) for three days. These data suggest that MSCs can improve the growth kinetics of aged CCs. CCs retaining intact telomere are present in old hearts and could be obtained based on their self-renewing capability. Although these aged CCs with reduced growth kinetics are improved by MSCs via cell–cell contact, the effect is minimal.

Bone marrow-derived mesenchymal stem cells in three-dimensional co-culture attenuate degeneration of nucleus pulposus cells

Intervertebral disc degeneration (IDD) is an irreversible aging-associated clinical condition of unclear etiology. Mesenchymal stem cells (MSCs) have the potential to delay IDD, but the mechanisms by which MSCs attenuate senescence-related degeneration of nucleus pulposus cells (NPCs) remain uncertain. The present study employed a three-dimensional (3D) co-culture system to explore the influence of MSCs on NPC degeneration induced by TNF-α in rat cells. We found that co-culture with bone marrow-derived MSCs (BMSCs) reduced senescence-associated β-galactosidase expression, increased cell proliferation, decreased matrix metalloproteinase 9, increased Coll-IIa production, and reduced TGFβ/NF-κB signaling in senescent NPCs. In addition, expression of zinc metallopeptidase STE24 (ZMPSTE24), whose dysfunction is related to premature cell senescence and aging, was decreased in senescent NPCs but restored upon BMSC co-culture. Accordingly, ZMPSTE24 overexpression in NPCs inhibited the pro-senescence effects of TGFβ/NF-κB activation upon TNF-α stimulation, while both CRISPR/Cas9-mediated silencing and pharmacological ZMPSTE24 inhibition prevented those effects. Ex-vivo experiments on NP explants provided supporting evidence for the protective effect of MSCs against NPC senescence and IDD. Although further molecular studies are necessary, our results suggest that MSCs may attenuate or prevent NP fibrosis and restore the viability and functional status of NPCs through upregulation of ZMPSTE24.

Hypoxia preconditioning promotes bone marrow mesenchymal stem cells survival by inducing HIF-1α in injured neuronal cells derived exosomes culture system

Bone marrow derived stem cells (BMSCs) transplantation are viewed as a promising therapeutic candidate for spinal cord injury (SCI). However, the inflammatory microenvironment in the spinal cord following SCI limits the survival and efficacy of transplanted BMSCs. In this study, we investigate whether injured neuronal cells derived exosomes would influence the survival of transplanted BMSCs after SCI. In order to mimic the microenvironment in SCI that the neuronal cells or transplanted BMSCs suffer in vivo, PC12 cells conditioned medium and PC12 cell’s exosomes collected from H₂O₂-treated PC12 cell’s culture medium were cultured with BMSCs under oxidative stress in vitro. PC12 cells conditioned medium and PC12 cell’s exosomes significantly accelerated the apoptosis of BMSCs induced by H₂O₂. Moreover, the cleaved caspase-3, cytochrome (Cyt) C, lactate dehydrogenase (LDH) releases, and apoptotic percentage were increased, and the ratio of Bcl-2/Bax and cell viability were decreased. Inhibition of exosome secretion via Rab27a small interfering RNA prevented BMSCs apoptosis in vitro. In addition, hypoxia-preconditioned promoted the survival of BMSCs under oxidative stress both in vivo after SCI and in vitro. Our results also indicate that HIF-1α plays a central role in the survival of BMSCs in hypoxia pretreatment under oxidative stress conditions. siRNA-HIF-1α increased apoptosis of BMSCs; in contrast, HIF-1α inducer FG-4592 attenuated apoptosis of BMSCs. Taken together, we found that the injured PC12 cells derived exosomes accelerate BMSCs apoptosis after SCI and in vitro, hypoxia pretreatment or activating expression of HIF-1α to be important in the survival of BMSCs after transplantation, which provides a foundation for application of BMSCs in therapeutic potential for SCI.

α-Lipoic acid and amlodipine/perindopril combination potentiate the therapeutic effect of mesenchymal stem cells on isoproterenol induced cardiac injury in rats

Cardiac injury is a dangerous disease and become a greater issue in the forthcoming decades. The ultimate goal is to prevent the progression of heart failure and apoptotic processes. Cardiac tissue may regenerate itself but to certain extent depending on the number of resident stem cells that is limited. Thus, research had been focused on bone marrow derived stem cells (BM-MSCs) as a promising therapy in different types of tissues, including the heart. This study is designed not only to assess the therapeutic effect of BM-MSCs but also to improve their therapeutic effect in combination with antioxidant α-lipoic acid (ALA) and antihypertensive therapeutic drug form (AP) against isoproterenol-induced cardiac injury and compared with that of BM-MSCs alone. Cardiac injury was induced in 70 male rats by Isoproterenol (ISO was injected s.c. for four consecutive days). Experimental animals were divided into six ISO-treated groups beside a control non treated one. The six ISO-treated groups were divided into: ISO group, ISO+BM-MSCs group, ISO+ALA group, ISO+AP group, ISO+ALA+AP group and ISO+ALA+AP+BM-MSCs group, the last five groups were treated with the examined materials after one week of ISO injection. Isoproterenol significantly increased serum CK-MB, LDH activities, Troponin1 and TNF-α. Oxidative stress is evidenced by the increased MDA, NO and Caspase-3 activity associated with significant reduction of GSH content and SOD activity in cardiac tissue. Furthermore, mRNA expression of NFκB and iNOS were significantly up regulated and eNOS mRNA expression was down regulated. Administration of BM-MSCs, ALA and AP alone significantly mitigated the induced cardiac injury. Concomitant administration of ALA and AP after BM-MSCs induced a more pronounced improving effect on cardiac functions. In conclusion, the concomitant administration of ALA and AP after BM-MSCs infusion increases the cellular antioxidant levels of cardiac tissue that improves the repairing function of BM-MSCs.

Apoptosis of bone marrow mesenchymal stromal/stem cells via the MAPK and endoplasmic reticulum stress signaling pathways

Therapy for myocardial regeneration using bone marrow stromal cells (BM-MSCs) has been applied to improve the cardiac function of subjects with acute myocardial infarction. However, the study of this therapy has encountered a bottleneck because BM-MSCs are prone to apoptosis in ischemic and anoxic environments. The goal of this study was to investigate the expression of mitogen activated protein kinase (MAPK) (p-38, JNK and ERK) and endoplasmic reticulum stress protein (caspase-12 and CHOP) during BM-MSC apoptosis. In a BM-MSC model of hypoxia and serum deprivation (H/SD), we observed the morphology and apoptotic rate of BM-MSCs for 24 h and found that the nuclear shrinkage and apoptosis rate increased gradually and reached a maximum apoptosis rate at the 6 h time point. Then, with the prolongation of the hypoxia time, the number of nuclear shrinkage cells and the apoptosis rate gradually decreased. The expression levels of p-38, JNK, ERK, procaspase-12, caspase-12 and CHOP increased at each H/SD time point. In addition, compared with the H/SD 6 h group, the nuclear shrinkage and apoptosis rate were decreased in the SB202190 and SP600125 groups but increased in the PD98059 group. Further, the expression of caspase-12 in the SB202190 group decreased, while the expression of procaspase-12 increased, compared with the H/SD 6 h group. Overall, our findings suggested that p-38, JNK, CHOP and caspase-12 play important roles in promoting the apoptosis of BM-MSCs, while ERK is contrary to other signals. Moreover, the apoptosis of BM-MSCs was induced by H/SD via the p-38-caspase-12 signaling pathway.

The positive effect of chick embryo and nutrient mixture on bone marrow- derived mesenchymal stem cells from aging rats

The aging of many mammalian tissues is associated with loss of functional adult stem cells, especially bone marrow-derived mesenchymal stem cells (BMSCs). This study was aimed to analyze the biological effect of chick embryo (CE) and nutrient mixture (NM) on the BMSCs of aging rats. The aging rat model was established to be induced by D-galactose (500 mg/kg/d) for 90 days. Meanwhile, aging rats were fed with CE and NM in different dose manner by intragastric administration. At the end of the experimental period, serum was collected from rats and used for BMSCs culture. Flow cytometric analysis was used to investigate the BMSCs surface markers. Alizarin Red and oil red O staining were performed to evaluate the multi-lineage differentiation of BMSCs. The results showed that CE plus NM increased the telomere length of BMSCs and promoted BMSCs proliferation. Moreover, CE plus NM administration promoted BMSCs differentiation into osteoblasts and suppressed differentiation into adipocytes. High-throughput sequencing analysis revealed that there were 326 genes were up-regulated and 59 genes were down-regulated in BMSCs of aging rats treated with CE plus NM. In conclusion, CE plus NM supplement had potential to delay aging through the recovery of BMSCs senescence and could be used as a safe effective approach for nutritional therapy of anti-aging.

The harsh microenvironment in infarcted heart accelerates transplanted bone marrow mesenchymal stem cells injury: the role of injured cardiomyocytes-derived exosomes

Stem cell therapy can be used to repair and regenerate damaged hearts tissue; nevertheless, the low survival rate of transplanted cells limits their therapeutic efficacy. Recently, it has been proposed that exosomes regulate multiple cellular processes by mediating cell survival and communication among cells. The following study investigates whether injured cardiomyocytes-derived exosomes (cardiac exosomes) affect the survival of transplanted bone marrow mesenchymal stem cells (BMSCs) in infarcted heart. To mimic the harsh microenvironment in infarcted heart that the cardiomyocytes or transplanted BMSCs encounter in vivo, cardiomyocytes conditioned medium and cardiac exosomes collected from H₂O₂-treated cardiomyocytes culture medium were cultured with BMSCs under oxidative stress in vitro. Cardiomyocytes conditioned medium and cardiac exosomes significantly accelerated the injury of BMSCs induced by H₂O₂; increased cleaved caspase-3/caspase-3 and apoptotic percentage, and decreased the ratio of Bcl-2/Bax and cell viability in those cells. Next, we explored the role of cardiac exosomes in the survival of transplanted BMSCs in vivo by constructing a Rab27a knockout (KO) mice model by a transcription activator-like effector nuclease (TALEN) genome-editing technique; Rab27a is a family of GTPases, which has critical role in secretion of exosomes. Male mouse GFP-modified BMSCs were implanted into the viable myocardium bordering the infarction in Rab27a KO and wild-type female mice. The obtained results showed that the transplanted BMSCs survival in infarcted heart was increased in Rab27a KO mice by the higher level of Y-chromosome Sry DNA, GFP mRNA, and the GFP fluorescence signal intensity. To sum up, these findings revealed that the injured cardiomyocytes-derived exosomes accelerate transplanted BMSCs injury in infarcted heart, thus highlighting a new mechanism underlying the survival of transplanted cells after myocardial infarction.

Application of Stem Cell Technology in Antiaging and Aging-Related Diseases

Stem cells are one kind of cells that have the potential of proliferation and differentiation. The human beings are originated from a totipotential stem cell-fertilized egg. After birth, the proliferation and differentiation of stem cells contribute to the development and maturation of individual tissues and organs. After maturation, aging is a phases of the life process, the stem cells within the individual's tissues ensure the metabolism of different cells and tissues, such as the hematopoietic stem cells in the bone marrow, which ensure there are still enough red blood cells (RBCs) being responsible for the mission of transporting oxygen after a single RBC has completed its 120-day physiological life cycle. After pathological damage and necrosis occurring on the intestinal epithelial cells or tubular epithelial cells, there will be regenerative epithelial cells continuing to maintain the integrity of the structure and function of the intestine and renal tubules. The role of stem cells in the regeneration and repair of tissues and organs is not only because of the ability of proliferation and differentiation of stem cells but also of the secretion function of stem cells, which secrete various growth factors and cytokines to regulate the tissue microenvironment. For example, mesenchymal stem cells derived from bone marrow are important regulators in bone marrow hematopoietic stem cell niche. Mesenchymal stem cells maintain the "stemness" of hematopoietic stem cells by secreting various cytokines.Aging is a phases of the life process, and all creatures obey this rule of nature. Different organs of the body have different time of entering into aging. Aging is reflected in structural changes and reduced function. Among them, the reduction of regeneration and repair capacity is the main feature of aging. As we age, the aging of stem cells in human tissues is a major cause of the decline in tissue regeneration capacity. Therefore, the elderly's ability of regenerate and repair can be improved by application of advance stem cell technology. It can delay the aging process and treat aged diseases (showed in Fig. 16.1).

New Trends in Heart Regeneration: A Review

In this review, we focus on new approaches that could lead to the regeneration of heart muscle and the restoration of cardiac muscle function derived from newly-formed cardiomyocytes. Various strategies for the production of cardiomyocytes from embryonic stem cells, induced pluripotent stem cells, adult bone marrow stem cells and cardiac spheres from human heart biopsies are described. Pathological conditions which lead to atherosclerosis and coronary artery disease often are followed by myocardial infarction causing myocardial cell death. After cell death, there is very little self-regeneration of the cardiac muscle tissue, which is replaced by non-contractile connective tissue, thus weakening the ability of the heart muscle to contract fully and leading to heart failure. A number of experimental research approaches to stimulate heart muscle regeneration with the hope of regaining normal or near normal heart function in the damaged heart muscle have been attempted. Some of these very interesting studies have used a variety of stem cell types in combination with potential cardiogenic differentiation factors in an attempt to promote differentiation of new cardiac muscle for possible future use in the clinical treatment of patients who have suffered heart muscle damage from acute myocardial infarctions or related cardiovascular diseases. Although progress has been made in recent years relative to promoting the differentiation of cardiac muscle tissue from non-muscle cells, much work remains to be done for this technology to be used routinely in translational clinical medicine to treat patients with damaged heart muscle tissue and return such individuals to pre-heart-attack activity levels.