Follistatin-like 1 protects mesenchymal stem cells from hypoxic damage and enhances their therapeutic efficacy in a mouse myocardial infarction model

Post-symptomatic administration of hMSCs exerts therapeutic effects in SCA2 mice

BACKGROUND

Defects in the ataxin-2 (ATXN-2) protein and CAG trinucleotide repeat expansion in its coding gene, Atxn-2, cause the neurodegenerative disorder spinocerebellar ataxia type 2 (SCA2). While clinical studies suggest potential benefits of human-derived mesenchymal stem cells (hMSCs) for treating various ataxias, the exact mechanisms underlying their therapeutic effects and interaction with host tissue to stimulate neurotrophin expression remain unclear specifically in the context of SCA2.

METHODS

Human bone marrow-derived MSCs (hMSCs) were injected into the cisterna magna of 26-week-old wild-type and SCA2 mice. Mice were assessed for impaired motor coordination using the accelerating rotarod, open field test, and composite phenotype scoring. At 50 weeks, the cerebellum vermis was harvested for protein assessment and immunohistochemical analysis.

RESULTS

Significant loss of NeuN and calbindin was observed in 25-week-old SCA2 mice. However, after receiving multiple injections of hMSCs starting at 26 weeks of age, these mice exhibited a significant improvement in abnormal motor performance and a protective effect on Purkinje cells. This beneficial effect persisted until the mice reached 50 weeks of age, at which point they were sacrificed to study further mechanistic events triggered by the administration of hMSCs. Calbindin-positive cells in the Purkinje cell layer expressed bone-derived neurotrophic factor after hMSC administration, contributing to the protection of cerebellar neurons from cell death.

CONCLUSION

In conclusion, repeated administration of hMSCs shows promise in alleviating SCA2 symptoms by preserving Purkinje cells, improving neurotrophic support, and reducing inflammation, ultimately leading to the preservation of locomotor function in SCA2 mice.

FSTL-1 loaded 3D bioprinted vascular patch regenerates the ischemic heart tissue

Cardiac patch strategies are developed as a promising approach to regenerate the injured heart after myocardial infarction (MI). This study integrated 3D bioprinting and cardioprotective paracrine signaling to fabricate vascular patch devices containing endothelial cells (ECs) and the regenerative follistatin-like 1 (FSTL1) peptide. Engineered patch supported the 3D culture of ECs in both static and dynamic culture, forming a uniform endothelium on the printed channels. Implantation of vascular patch onto a rat model of acute MI resulted in significant reduction of scar formation, left ventricle dilation, and wall thinning, as well as enhanced ejection fraction. Furthermore, increased vascularization and proliferation of cardiomyocytes were observed in hearts treated with patches. These findings highlight the remarkable capacity of 3D bioprinted vascular patch to augment the endogenous regenerative capacity of mammalian heart, together with the exogenous cardioprotective function, to serve as a robust therapeutic device to treat acute MI.

Genetically modified mesenchymal stromal cells: a cell-based therapy offering more efficient repair after myocardial infarction

Myocardial infarction (MI) is a serious complication of coronary artery disease. This condition is common worldwide and has a profound impact on patients' lives and quality of life. Despite significant advances in the treatment of heart disease in modern medicine, the efficient treatment of MI still faces a number of challenges. Problems such as scar formation and loss of myocardial function after a heart attack still limit patients' recovery. Therefore, the search for a new therapeutic tool that can promote repair and regeneration of myocardial tissue has become crucial. In this context, mesenchymal stromal cells (MSCs) have attracted much attention as a potential therapeutic tool. MSCs are a class of adult stem cells with multidirectional differentiation potential, derived from bone marrow, fat, placenta and other tissues, and possessing properties such as self-renewal and immunomodulation. The application of MSCs may provide a new direction for the treatment of MI. These stem cells have the potential to differentiate into cardiomyocytes and vascular endothelial cells in damaged tissue and to repair and protect myocardial tissue through anti-inflammatory, anti-fibrotic and pro-neovascularization mechanisms. However, the clinical results of MSCs transplantation for the treatment of MI are less satisfactory due to the limitations of the native function of MSCs. Genetic modification has overcome problems such as the low survival rate of transplanted MSCs in vivo and enhanced their functions of promoting neovascularization and differentiation into cardiomyocytes, paving the way for them to become an effective tool for repair therapy after MI. In previous studies, MSCs have shown some therapeutic potential in experimental animals and preliminary clinical trials. This review aims to provide readers with a comprehensive and in-depth understanding to promote the wider application of engineering MSCs in the field of MI therapy, offering new hope for recovery and improved survival of cardiac patients.

Epicardial EMT and cardiac repair: an update

Epicardial epithelial-to-mesenchymal transition (EMT) plays a pivotal role in both heart development and injury response and involves dynamic cellular changes that are essential for cardiogenesis and myocardial repair. Specifically, epicardial EMT is a crucial process in which epicardial cells lose polarity, migrate into the myocardium, and differentiate into various cardiac cell types during development and repair. Importantly, following EMT, the epicardium becomes a source of paracrine factors that support cardiac growth at the last stages of cardiogenesis and contribute to cardiac remodeling after injury. As such, EMT seems to represent a fundamental step in cardiac repair. Nevertheless, endogenous EMT alone is insufficient to stimulate adequate repair. Redirecting and amplifying epicardial EMT pathways offers promising avenues for the development of innovative therapeutic strategies and treatment approaches for heart disease. In this review, we present a synthesis of recent literature highlighting the significance of epicardial EMT reactivation in adult heart disease patients.

The dual role of mesenchymal stem cells in apoptosis regulation

Mesenchymal stem cells (MSCs) are widely distributed pluripotent stem cells with powerful immunomodulatory capacity. MSCs transplantation therapy (MSCT) is widely used in the fields of tissue regeneration and repair, and treatment of inflammatory diseases. Apoptosis is an important way for tissues to maintain cell renewal, but it also plays an important role in various diseases. And many studies have shown that MSCs improves the diseases by regulating cell apoptosis. The regulation of MSCs on apoptosis is double-sided. On the one hand, MSCs significantly inhibit the apoptosis of diseased cells. On the other hand, MSCs also promote the apoptosis of tumor cells and excessive immune cells. Furthermore, MSCs regulate apoptosis through multiple molecules and pathways, including three classical apoptotic signaling pathways and other pathways. In this review, we summarize the current evidence on the regulation of apoptosis by MSCs.

Exploring Cutting-Edge Approaches to Potentiate Mesenchymal Stem Cell and Exosome Therapy for Myocardial Infarction

Cardiovascular diseases (CVDs) continue to be a significant global health concern. Many studies have reported promising outcomes from using MSCs and their secreted exosomes in managing various cardiovascular-related diseases like myocardial infarction (MI). MSCs and exosomes have demonstrated considerable potential in promoting regeneration and neovascularization, as well as exerting beneficial effects against apoptosis, remodeling, and inflammation in cases of myocardial infarction. Nonetheless, ensuring the durability and effectiveness of MSCs and exosomes following in vivo transplantation remains a significant concern. Recently, novel methods have emerged to improve their effectiveness and robustness, such as employing preconditioning statuses, modifying MSC and their exosomes, targeted drug delivery with exosomes, biomaterials, and combination therapy. Herein, we summarize the novel approaches that intensify the therapeutic application of MSC and their derived exosomes in treating MI.

From Beats to Metabolism: the Heart at the Core of Interorgan Metabolic Cross Talk

The heart, once considered a mere blood pump, is now recognized as a multifunctional metabolic and endocrine organ. Its function is tightly regulated by various metabolic processes, at the same time it serves as an endocrine organ, secreting bioactive molecules that impact systemic metabolism. In recent years, research has shed light on the intricate interplay between the heart and other metabolic organs, such as adipose tissue, liver, and skeletal muscle. The metabolic flexibility of the heart and its ability to switch between different energy substrates play a crucial role in maintaining cardiac function and overall metabolic homeostasis. Gaining a comprehensive understanding of how metabolic disorders disrupt cardiac metabolism is crucial, as it plays a pivotal role in the development and progression of cardiac diseases. The emerging understanding of the heart as a metabolic and endocrine organ highlights its essential contribution to whole body metabolic regulation and offers new insights into the pathogenesis of metabolic diseases, such as obesity, diabetes, and cardiovascular disorders. In this review, we provide an in-depth exploration of the heart's metabolic and endocrine functions, emphasizing its role in systemic metabolism and the interplay between the heart and other metabolic organs. Furthermore, emerging evidence suggests a correlation between heart disease and other conditions such as aging and cancer, indicating that the metabolic dysfunction observed in these conditions may share common underlying mechanisms. By unraveling the complex mechanisms underlying cardiac metabolism, we aim to contribute to the development of novel therapeutic strategies for metabolic diseases and improve overall cardiovascular health.

An immunometabolic patch facilitates mesenchymal stromal/stem cell therapy for myocardial infarction through a macrophage-dependent mechanism

Mesenchymal stromal/stem cells (MSCs) have emerged as a promising approach against myocardial infarction. Due to hostile hyperinflammation, however, poor retention of transplanted cells seriously impedes their clinical applications. Proinflammatory M1 macrophages, which rely on glycolysis as their main energy source, aggravate hyperinflammatory response and cardiac injury in ischemic region. Here, we showed that the administration of an inhibitor of glycolysis, 2-deoxy-d-glucose (2-DG), blocked the hyperinflammatory response within the ischemic myocardium and subsequently extended effective retention of transplanted MSCs. Mechanistically, 2-DG blocked the proinflammatory polarization of macrophages and suppressed the production of inflammatory cytokines. Selective macrophage depletion abrogated this curative effect. Finally, to avoid potential organ toxicity caused by systemic inhibition of glycolysis, we developed a novel chitosan/gelatin-based 2-DG patch that directly adhered to the infarcted region and facilitated MSC-mediated cardiac healing with undetectable side effects. This study pioneered the application of an immunometabolic patch in MSC-based therapy and provided insights into the therapeutic mechanism and advantages of this innovative biomaterial.

Cardiac cell therapies for the treatment of acute myocardial infarction in mice: systematic review and meta-analysis

Backgound Aims: This meta-analysis aims at summarizing the whole body of research on cell therapies for acute myocardial infarction (MI) in the mouse model to bring forward ongoing research in this field of regenerative medicine. Despite rather modest effects in clinical trials, pre-clinical studies continue to report beneficial effects of cardiac cell therapies for cardiac repair following acute ischemic injury. Results: The authors' meta-analysis of data from 166 mouse studies comprising 257 experimental groups demonstrated a significant improvement in left ventricular ejection fraction of 10.21% after cell therapy compared with control animals. Subgroup analysis indicated that second-generation cell therapies such as cardiac progenitor cells and pluripotent stem cell derivatives had the highest therapeutic potential for minimizing myocardial damage post-MI. Conclusions: Whereas the vision of functional tissue replacement has been replaced by the concept of regional scar modulation in most of the investigated studies, rather basic methods for assessing cardiac function were most frequently used. Hence, future studies will highly benefit from integrating methods for assessment of regional wall properties to evolve a deeper understanding of how to modulate cardiac healing after acute MI.

MEG3 alleviates ankylosing spondylitis by suppressing osteogenic differentiation of mesenchymal stem cells through regulating microRNA-125a-5p-mediated TNFAIP3

Osteoblasts are important regulators of bone formation, but their roles in ankylosing spondylitis (AS) remain unclear. This study aims to explore the role of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) MEG3 in AS. Serum from AS patients as well as AS mesenchymal stem cells (ASMSCs) and healthy donors mesenchymal stem cells (HDMSCs) was collected. Accordingly, poorly expressed MEG3 and TNF alpha induced protein 3 (TNFAIP3) as well as overexpressed microRNA-125a-5p (miR-125a-5p) were noted in the serum of AS patients and in ASMSCs during the osteogenic induction process. Meanwhile, the interaction among MEG3, miR-125a-5p, and TNFAIP3 was determined and their effect on osteoblast activity was examined in vitro and in vivo. Overexpression of MEG3 and TNFAIP3 or inhibition of miR-125a-5p was found to inactivate the Wnt/β-catenin pathway, thus suppressing osteogenic differentiation of MSCs. MEG3 competitively bound to miR-125a-5p to increase TNFAIP3 expression, thereby inactivating the Wnt/β-catenin pathway and repressing the osteogenic differentiation of MSCs. In proteoglycan (PG)-induced AS mouse models, MEG3 also reduced osteogenic activity of MSCs to inhibit AS progression through the miR-125a-5p/TNFAIP3/Wnt/β-catenin axis. Therefore, up-regulation of MEG3 or depletion of miR-125a-5p holds potential of alleviating AS, which sheds light on a new therapeutic strategy for AS treatment.

Follistatin-like 1 and its paralogs in heart development and cardiovascular disease

Cardiovascular diseases (CVDs) are a group of disorders affecting the heart and blood vessels and a leading cause of death worldwide. Thus, there is a need to identify new cardiokines that may protect the heart from damage as reported in GBD 2017 Causes of Death Collaborators (2018) (The Lancet 392:1736-1788). Follistatin-like 1 (FSTL1) is a cardiokine that is highly expressed in the heart and released to the serum after cardiac injury where it is associated with CVD and predicts poor outcome. The action of FSTL1 likely depends not only on the tissue source but also post-translation modifications that are target tissue- and cell-specific. Animal studies examining the effect of FSTL1 in various models of heart disease have exploded over the past 15 years and primarily report a protective effect spanning from inhibiting inflammation via transforming growth factor, preventing remodeling and fibrosis to promoting angiogenesis and hypertrophy. A better understanding of FSTL1 and its homologs is needed to determine whether this protein could be a useful novel biomarker to predict poor outcome and death and whether it has therapeutic potential. The aim of this review is to provide a comprehensive description of the literature for this family of proteins in order to better understand their role in normal physiology and CVD.

Endogenous Follistatin-like 1 guarantees the immunomodulatory properties of mesenchymal stem cells during liver fibrotic therapy

Background

Mesenchymal stem cell (MSC) therapy has been shown to be a promising option for liver fibrosis treatment. However, critical factors affecting the efficacy of MSC therapy for liver fibrosis remain unknown. Follistatin-like 1 (FSTL1), a TGF-β-induced matricellular protein, is documented as an intrinsic regulator of proliferation and differentiation in MSCs. In the present study, we characterized the potential role of FSTL1 in MSC-based anti-fibrotic therapy and further elucidated the mechanisms underlying its action.

Methods

Human umbilical cord-derived MSCs were characterized by flow cytometry. FSTL1^low MSCs were achieved by FSTL1 siRNA. Migration capacity was evaluated by wound-healing and transwell assay. A murine liver fibrotic model was created by carbon tetrachloride (CCl₄) injection, while control MSCs or FSTL1^low MSC were transplanted via intravenous injection 12 weeks post CCl₄ injection. Histopathology, liver function, fibrosis degree, and inflammation were analysed thereafter. Inflammatory cell infiltration was evaluated by flow cytometry after hepatic nonparenchymal cell isolation. An MSC-macrophage co-culture system was constructed to further confirm the role of FSTL1 in the immunosuppressive capacity of MSCs. RNA sequencing was used to screen target genes of FSTL1.

Results

FSTL1^low MSCs had comparable gene expression for surface markers to wildtype but limited differentiation and migration capacity. FSTL1^low MSCs failed to alleviate CCl₄-induced hepatic fibrosis in a mouse model. Our data indicated that FSTL1 is essential for the immunosuppressive action of MSCs on inflammatory macrophages during liver fibrotic therapy. FSTL1 silencing attenuated this capacity by inhibiting the downstream JAK/STAT1/IDO pathway.

Conclusions

Our data suggest that FSTL1 facilitates the immunosuppression of MSCs on macrophages and that guarantee the anti-fibrotic effect of MSCs in liver fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03042-4.

Calming egress of inflammatory monocytes and related septic shock by therapeutic CCR2 silencing using macrophage-derived extracellular vesicles

Uncontrolled inflammation, featuring the aggravated mobilization of Ly6C^high inflammatory monocytes (Mos), may cause high morbidity and mortality in the pathogenesis of sepsis-associated immune disorders. Inspired by the similar membrane protein profile of extracellular vehicles (EVs) and their parent cells, EVs are generated from immortalized bone marrow-derived macrophages (Mps) for Mo/Mp-targeting drug delivery. Compared with MSC-EVs, Mac-EVs are more efficiently internalized by inflammatory Mo/Mps in vitro as well as by septic spleen in vivo. By loading with siRNA targeting the chemokine receptor CCR2, the mediator for chemotaxis of inflammatory Mo/Mps, Mac-EV^siCCR2 not only restrains chemotaxis of inflammatory Mo/Mps but also relieves septic symptoms in mice by limiting the mobilization of splenic inflammatory monocytes and calming the subsequent serum cytokine storm. The current study provides functional evidence for the successful therapeutic targeting of septic inflammatory Mos, mandating the clinical development of CCR2 inhibition in patients with infectious diseases.

Peptide hormone ELABELA promotes rat bone marrow-derived mesenchymal stem cell proliferation and migration by manipulating the cell cycle through the PI3K/AKT pathway under the hypoxia and ischemia microenvironmemt

BACKGROUND

Mesenchymal stem cells (MSCs) are emerging as a potential candidate for stem cell transplantation to repair myocardial tissue in myocardial infarctions (MI). However, there are some pivotal limitations such as poor survival and low migration capacity of MSCs in hypoxic and ischemic microenvironments of MI. Our previous work verified that ELABELA (also abbreviated as ELA), a peptide hormone, could play a role as a growth factor and prolong the life span of rat bone marrow-derived mesenchymal stem cells (RAT BM-MSCs) under hypoxic and ischemic conditions. Nevertheless, the influence of ELA on the cell cycle, proliferation, and migration remains elusive. This study will further explore the improvement of the biological functions of ELA-treated RAT BM-MSCs, so as to provide a reference for improving the efficacy of RAT BM-MSCs in MI.

METHODS

Rat BM-MSCs were isolated from 80 to 120 g Sprague Dawley rats by flushing femurs and tibias under the aseptic condition. RAT BM-MSCs of the third passage were divided into control group, hypoxic/ischemic (H/I) group, ELA group, ELA-LY group and LY group. RAT BM-MSCs were cultured under normoxia in control group. In H/I group, RAT BM-MSCs were exposed to hypoxia (1% O2) and serum deprivation for 24 h. RAT BM-MSCs in ELA group were treated with 5 µM ELA prior to the H/I exposure for 24 h. The PI3K/AKT inhibitor, LY294002 (50 µM), was used in ELA-LY group and LY group to observe the effect of ELA on PI3K/AKT activation. Cell proliferation ability was examined by CCK-8. Cell cycle was assessed with flow cytometry. Cell migration was evaluated by Transwell assay. Expression levels of total-AKT, phosphorylated-AKT, and cell cycle-associated proteins were examined by Western blotting.

RESULTS

ELA-treated RAT BM-MSCs exhibited significantly higher proliferation ability, cell viability, and migration under H/I conditions. The cell cycle analysis showed that an increased proportion of cells in the S and G2/M phases of the cell cycle were observed in ELA-treated RAT BM-MSCs. The addition of ELA activated the PI3K/AKT signaling pathway. Additionally, upon treating with the inhibitor of the PI3K/AKT signaling pathway, ELA-triggered proliferation, cell viability, and migration were abrogated.

CONCLUSIONS

ELA can be used to enhance the proliferation ability, cell viability, and migration of RAT BM-MSCs through the PI3K/AKT signaling pathway and alleviate cell cycle arrest at the G0/G1 phase under hypoxic and ischemic injury. Thus, this study provides a promising strategy that ELA may help to optimize the mesenchymal stem cell-based therapy in MI.

FSTL1-USP10-Notch1 Signaling Axis Protects Against Cardiac Dysfunction Through Inhibition of Myocardial Fibrosis in Diabetic Mice

The incidence of type 2 diabetes mellitus (T2DM) has been increasing globally, and T2DM patients are at an increased risk of major cardiac events such as myocardial infarction (MI). Nevertheless, the molecular mechanisms underlying MI injury in T2DM remain elusive. Ubiquitin-specific protease 10 (USP10) functions as a NICD1 (Notch1 receptor) deubiquitinase that fine-tunes the essential myocardial fibrosis regulator Notch signaling. Follistatin-like protein 1 (FSTL1) is a cardiokine with proven benefits in multiple pathological processes including cardiac fibrosis and insulin resistance. This study was designed to examine the roles of FSTL1/USP10/Notch1 signaling in MI-induced cardiac dysfunction in T2DM. High-fat-diet-treated, 8-week-old C57BL/6J mice and db/db T2DM mice were used. Intracardiac delivery of AAV9-FSTL1 was performed in T2DM mice following MI surgery with or without intraperitoneal injection of crenigacestat (LY3039478) and spautin-1. Our results demonstrated that FSTL1 improved cardiac function following MI under T2DM by reducing serum lactate dehydrogenase (LDH) and myocardial apoptosis as well as cardiac fibrosis. Further in vivo studies revealed that the protective role of FSTL1 against MI injury in T2DM was mediated by the activation of USP10/Notch1. FSTL1 protected cardiac fibroblasts (CFs) against DM-MI-induced cardiofibroblasts injury by suppressing the levels of fibrosis markers, and reducing LDH and MDA concentrations in a USP10/Notch1-dependent manner. In conclusion, FSTL1 treatment ameliorated cardiac dysfunction in MI with co-existent T2DM, possibly through inhibition of myocardial fibrosis and apoptosis by upregulating USP10/Notch1 signaling. This finding suggests the clinical relevance and therapeutic potential of FSTL1 in T2DM-associated MI and other cardiovascular diseases.

E3 ligase activity of Carboxyl terminus of Hsc70 interacting protein (CHIP) in Wharton's jelly derived mesenchymal stem cells improves their persistence under hyperglycemic stress and promotes the prophylactic effects against diabetic cardiac damages

Recent studies indicate that umbilical cord stem cells are cytoprotective against several disorders. One critical limitation in using stem cells is reduction in their viability under stressful conditions, such as diabetes. However, the molecular intricacies responsible for diabetic conditions are not fully elucidated. In this study, we found that high glucose (HG) conditions induced loss of chaperone homeostasis, stabilized PTEN, triggered the downstream signaling cascade, and induced apoptosis and oxidative stress in Wharton's jelly derived mesenchymal stem cells (WJMSCs). Increased Carboxyl terminus of Hsc70 interacting protein (CHIP) expression promoted phosphatase and tensin homolog (PTEN) degradation via the ubiquitin-proteasome system and shortened its half-life during HG stress. Docking studies confirmed the interaction of CHIP with PTEN and FOXO3a with the Bim promoter region. Further, it was found that the chaperone system is involved in CHIP-mediated PTEN proteasomal degradation. CHIP depletion stabilizes PTEN whereas PTEN inhibition showed an inverse effect. CHIP overactivation suppressed the binding of FOXO3a with bim. Coculturing CHIP overexpressed WJMSCs suppressed HG-induced apoptosis and oxidative stress in embryo derived cardiac cell lines. CHIP overexpressing and PTEN silenced WJMSCs ameliorated diabetic effects in streptozotocin (STZ) induced diabetic rats and further improved their body weight and heart weight, and rescued from hyperglycemia-induced cardiac injury. Considering these, the current study suggests that CHIP confers resistance to apoptosis and acts as a potentiation factor in WJMSCs to provide protection from degenerative effects of diabetes.

CHIP-overexpressing Wharton's jelly-derived mesenchymal stem cells attenuate hyperglycemia-induced oxidative stress-mediated kidney injuries in diabetic rats

Accumulating studies have demonstrated the protective roles of mesenchymal stem cells against several disorders. However, one of their crucial limitations is reduced viability under stress conditions, including the hyperglycemia induced by diabetes. The molecular mechanisms involved in diabetes-induced kidney injuries are not fully elucidated. In this study, we found that high glucose (HG) reduced human proximal tubular epithelial cell viability. Further, hyperglycemia induced oxidative stress-mediated apoptosis and fibrosis in HK-2 cells via activation of the mitogen-activated protein kinases (MAPKs) including c-Jun N-terminal kinase JNK and p38 kinase. Carboxyl terminus of HSP70 interacting protein (CHIP) overactivation considerably rescued cell viability under HG stress. Moreover, Western blot analysis, flow cytometry, and MitoSOX staining revealed that hyperglycemia-induced mitochondrial oxidative stress production and apoptosis were attenuated in CHIP-overexpressing Wharton's jelly-derived mesenchymal stem cells (WJMSCs). Co-culture with CHIP-expressing WJMSCs maintained HK-2 cell viability, and inhibited apoptosis and fibrosis by attenuating HG-induced ROS-mediated MAPK activation. CHIP-overexpressing WJMSCs also rescued the decreased kidney weight and hyperglycemia-induced kidney damage observed in streptozotocin-induced diabetic rats. Cumulatively, the current research findings demonstrate that CHIP suppresses hyperglycemia-induced oxidative stress and confers resistance to MAPK-induced apoptosis and fibrosis, and suggests that CHIP protects WJMSCs and the high quality WJMSCs have therapeutic effects against diabetes-induced kidney injuries.

Vimentin-Rab7a Pathway Mediates the Migration of MSCs and Lead to Therapeutic Effects on ARDS

Acute respiratory distress syndrome (ARDS) is difficult to treat and has a high mortality rate. Mesenchymal stem cells (MSCs) have an important therapeutic effect in ARDS. While the mechanism of MSC migration to the lungs remains unclear, the role of MSCs is of great clinical significance. To this end, we constructed vimentin knockout mice, extracted bone MSCs from the mice, and used them for the treatment of LPS-induced ARDS. H&E staining and Masson staining of mouse lung tissue allowed us to assess the degree of damage and fibrosis of mouse lung tissue. By measuring serum TNF-α, TGF-β, and INF-γ, we were able to monitor the release of inflammatory factors. Finally, through immunoprecipitation and gene knockout experiments, we identified upstream molecules that regulate vimentin and elucidated the mechanism that mediates MSC migration. As a result, we found that MSCs from wild-type mice can significantly alleviate ARDS and reduce lung inflammation, while vimentin gene knockout reduced the therapeutic effect of MSCs in ARDS. Cytological experiments showed that vimentin gene knockout can significantly inhibit the migration of MSCs and showed that it changes the proliferation and differentiation status of MSCs. Further experiments found that vimentin's regulation of MSC migration is mainly mediated by Rab7a. Rab7a knockout blocked the migration of MSCs and weakened the therapeutic effect of MSCs in ARDS. In conclusion, we have shown that the Vimentin-Rab7a pathway mediates migration of MSCs and leads to therapeutic effects in ARDS.

Therapies to prevent post-infarction remodelling: From repair to regeneration

Myocardial infarction is the first cause of worldwide mortality, with an increasing incidence also reported in developing countries. Over the past decades, preclinical research and clinical trials continually tested the efficacy of cellular and acellular-based treatments. However, none of them resulted in a drug or device currently used in combination with either percutaneous coronary intervention or coronary artery bypass graft. Inflammatory, proliferation and remodelling phases follow the ischaemic event in the myocardial tissue. Only recently, single-cell sequencing analyses provided insights into the specific cell populations which determine the final fibrotic deposition in the affected region. In this review, ischaemia, inflammation, fibrosis, angiogenesis, cellular stress and fundamental cellular and molecular components are evaluated as therapeutic targets. Given the emerging evidence of biomaterial-based systems, the increasing use of injectable hydrogels/scaffolds and epicardial patches is reported both as acellular and cellularised/functionalised treatments. Since several variables influence the outcome of any experimented treatment, we return to the pathological basis with an unbiased view towards any specific process or cellular component. Thus, by evaluating the benefits and limitations of the approaches based on these targets, the reader can weigh the rationale of each of the strategies that reached the clinical trials stage. As recent studies focused on the relevance of the extracellular matrix in modulating ischaemic remodelling and enhancing myocardial regeneration, we aim to portray current trends in the field with this review. Finally, approaches towards feasible translational studies that are as yet unexplored are also suggested.

miR-200c-3p Regulates Epitelial-to-Mesenchymal Transition in Epicardial Mesothelial Cells by Targeting Epicardial Follistatin-Related Protein 1

Recent findings suggest that epithelial to mesenchymal transition (EMT), a key step during heart development, is involved in cardiac tissue repair following myocardial infarction (MI). MicroRNAs (miRNAs) act as key regulators in EMT processes; however, the mechanisms by which miRNAs target epicardial EMT remain largely unknown. Here, by using an in vitro model of epicardial EMT, we investigated the role of miRNAs as regulators of this process and their potential targets. EMT was induced in murine epicardial-mesothelial cells (EMCs) through TGF β1 treatment for 48, 72, and 96 h as indicated by the expression of EMT-related genes by qRT-PCR, WB, and immunofluorescence. Further, enhanced expression of stemness genes was also detected. Among several EMT-related miRNAs, miR-200c-3p expression resulted as the most strongly suppressed. Interestingly, we also found a significant upregulation of Follistatin-related protein 1 (FSTL1), a miR-200c predicted target already identified as a potent cardiogenic factor produced by epicardial cells that promotes regeneration following MI. Dual-luciferase reporter assay demonstrated that miR-200c-3p directly targeted the 3'-untranslated region of FSTL1 in EMCs. Consistently, WB analysis showed that knockdown of miR-200c-3p significantly increased FSTL1 expression, whereas overexpression of miR-200c-3p counteracted TGF β1-mediated FSTL1 upregulation. Importantly, FSTL1 silencing maintained epithelial features in EMCs, despite EMT induction by TGF β1, and attenuated EMT-associated traits, including migration and stemness. In conclusion, epicardial FSTL1, an important cardiogenic factor in its secreted form, induces EMT, stemness, and migration of EMCs in a miR-200c-3p dependent pathway.

Exosomal LncRNA-NEAT1 derived from MIF-treated mesenchymal stem cells protected against doxorubicin-induced cardiac senescence through sponging miR-221-3p

Background

The chemotherapy drug doxorubicin (Dox) is widely used for treating a variety of cancers. However, its high cardiotoxicity hampered its clinical use. Exosomes derived from stem cells showed a therapeutic effect against Dox-induced cardiomyopathy (DIC). Previous studies reported that exosomes derived from mesenchymal stem cells (MSCs) pretreated with macrophage migration inhibitory factor (MIF) (exosome^MIF) showed a cardioprotective effect through modulating long noncoding RNAs/microRNAs (lncRNAs/miRs). This study aimed to investigate the role of exosome^MIF in the treatment of DIC.

Results

Exosomes were isolated from control MSCs (exosome) and MIF-pretreated MSCs (exosome^MIF). Regulatory lncRNAs activated by MIF pretreatment were explored using genomics approaches. Fluorescence-labeled exosomes were tracked in vitro by fluorescence imaging. In vivo and in vitro, miR-221-3p mimic transfection enforced miR-221-3p overexpression, and senescence-associated β-galactosidase assay was applied to test cellular senescence. Exosomal delivering LncRNA-NEAT1 induced therapeutic effect in vivo was confirmed by echocardiography. It demonstrated that exosomes^MIF recovered the cardiac function and exerted the anti-senescent effect through LncRNA–NEAT1 transfer against Dox. TargetScan and luciferase assay showed that miR-221-3p targeted the Sirt2 3′-untranslated region. Silencing LncRNA–NEAT1 in MSCs, miR-221-3p overexpression or Sirt2 silencing in cardiomyocytes decreased the exosome^MIF-induced anti-senescent effect against Dox.

Conclusions

The results indicated exosome^MIF serving as a promising anti-senescent effector against Dox-induced cardiotoxicity through LncRNA–NEAT1 transfer, thus inhibiting miR-221-3p and leading to Sirt2 activation. The study proposed that exosome^MIF might have the potential to serve as a cardioprotective therapeutic agent during cancer chemotherapy.

Genetic Engineering as a Strategy to Improve the Therapeutic Efficacy of Mesenchymal Stem/Stromal Cells in Regenerative Medicine

Mesenchymal stem/stromal cells (MSCs) have been widely studied in the field of regenerative medicine for applications in the treatment of several disease settings. The therapeutic potential of MSCs has been evaluated in studies in vitro and in vivo, especially based on their anti-inflammatory and pro-regenerative action, through the secretion of soluble mediators. In many cases, however, insufficient engraftment and limited beneficial effects of MSCs indicate the need of approaches to enhance their survival, migration and therapeutic potential. Genetic engineering emerges as a means to induce the expression of different proteins and soluble factors with a wide range of applications, such as growth factors, cytokines, chemokines, transcription factors, enzymes and microRNAs. Distinct strategies have been applied to induce genetic modifications with the goal to enhance the potential of MCSs. This review aims to contribute to the update of the different genetically engineered tools employed for MSCs modification, as well as the factors investigated in different fields in which genetically engineered MSCs have been tested.

Novel Mechanisms of Exercise-Induced Cardioprotective Factors in Myocardial Infarction

Exercise training has been reported to ameliorate heart dysfunction in both humans and animals after myocardial infarction (MI). Exercise-induced cardioprotective factors have been implicated in mediating cardiac repair under pathological conditions. These protective factors secreted by or enriched in the heart could exert cardioprotective functions in an autocrine or paracrine manner. Extracellular vesicles, especially exosomes, contain key molecules and play an essential role in cell-to-cell communication via delivery of various factors, which may be a novel target to study the mechanism of exercise-induced benefits, besides traditional signaling pathways. This review is designed to demonstrate the function and underlying protective mechanism of exercise-induced cardioprotective factors in MI, with an aim to offer more potential therapeutic targets for MI.

Aminooxyacetic acid attenuates post-infarct cardiac dysfunction by balancing macrophage polarization through modulating macrophage metabolism in mice

Excessive activation of pro-inflammatory M1 macrophages following acute myocardial infarction (MI) aggravates adverse cardiac remodelling and heart dysfunction. There are two break points in the tricarboxylic acid cycle of M1 macrophages, and aspartate-arginosuccinate shunt compensates them. Aminooxyacetic acid (AOAA) is an inhibitor of aspartate aminotransferase in the aspartate-arginosuccinate shunt. Previous studies showed that manipulating macrophage metabolism may control macrophage polarization and inflammatory response. In this study, we aimed to clarify the effects of AOAA on macrophage metabolism and polarization and heart function after MI. In vitro, AOAA inhibited lactic acid and glycolysis and enhanced ATP levels in classically activated M1 macrophages. Besides, AOAA restrained pro-inflammatory M1 macrophages and promoted anti-inflammatory M2 phenotype. In vivo, MI mice were treated with AOAA or saline for three consecutive days. Remarkably, AOAA administration effectively inhibited the proportion of M1 macrophages and boosted M2-like phenotype, which subsequently attenuated infarct size as well as improved post-MI cardiac function. Additionally, AOAA attenuated NLRP3-Caspase1/IL-1β activation and decreased the release of IL-6 and TNF-α pro-inflammatory cytokines and reciprocally increased IL-10 anti-inflammatory cytokine level in both ischaemic myocardium and M1 macrophages. In conclusion, short-term AOAA treatment significantly improves cardiac function in mice with MI by balancing macrophage polarization through modulating macrophage metabolism and inhibiting NLRP3-Caspase1/IL-1β pathway.

Interventions in WNT Signaling to Induce Cardiomyocyte Proliferation: Crosstalk with Other Pathways

Myocardial infarction is a frequent cardiovascular event and a major cause for cardiomyocyte loss. In adult mammals, cardiomyocytes are traditionally considered to be terminally differentiated cells, unable to proliferate. Therefore, the wound-healing response in the infarct area typically yields scar tissue rather than newly formed cardiomyocytes. In the last decade, several lines of evidence have challenged the lack of proliferative capacity of the differentiated cardiomyocyte: studies in zebrafish and neonatal mammals have convincingly demonstrated the regenerative capacity of cardiomyocytes. Moreover, multiple signaling pathways have been identified in these models that-when activated in adult mammalian cardiomyocytes-can reactivate the cell cycle in these cells. However, cardiomyocytes frequently exit the cell cycle before symmetric division into daughter cells, leading to polyploidy and multinucleation. Now that there is more insight into the reactivation of the cell cycle machinery, other prerequisites for successful symmetric division of cardiomyocytes, such as the control of sarcomere disassembly to allow cytokinesis, require more investigation. This review aims to discuss the signaling pathways involved in cardiomyocyte proliferation, with a specific focus on wingless/int-1 protein signaling. Comparing the conflicting results from in vitro and in vivo studies on this pathway illustrates that the interaction with other cells and structures around the infarct is likely to be essential to determine the outcome of these interventions. The extensive crosstalk with other pathways implicated in cardiomyocyte proliferation calls for the identification of nodal points in the cell signaling before cardiomyocyte proliferation can be moved forward toward clinical application as a cure of cardiac disease. SIGNIFICANCE STATEMENT: Evidence is mounting that proliferation of pre-existing cardiomyocytes can be stimulated to repair injury of the heart. In this review article, an overview is provided of the different signaling pathways implicated in cardiomyocyte proliferation with emphasis on wingless/int-1 protein signaling, crosstalk between the pathways, and controversial results obtained in vitro and in vivo.

MiR-29a in mesenchymal stem cells inhibits FSTL1 secretion and promotes cardiac myocyte apoptosis in hypoxia-reoxygenation injury

BACKGROUND

Mesenchymal stem cells (MSCs) are under consideration for myocardial ischemia-reperfusion (I/R) injury therapy, but their mechanism remains to be evaluated. In this article, we aimed to study the effects of the miR-29a/follistatin-like 1 axis in bone marrow-derived mesenchymal stem cells on modulating myocyte apoptosis after hypoxia-reoxygenation (H/R) injury.

METHODS

An in vitro myocardial ischemia-reperfusion injury model of H9c2 cells was developed by hypoxia-reoxygenation injury. The mRNA levels of follistatin-like 1, Bcl-2, Bax, and miR-29a and the protein levels of Bcl-2, Bax, cleaved caspase-3, and components of the JAK2/STAT3 pathway were detected by qRT-PCR and western blotting, respectively. Secretion of follistatin-like 1 was evaluated by enzyme-linked immunosorbent assay. Cell apoptosis was evaluated by flow cytometry. The interaction between miR-29a and follistatin-like 1 was evaluated by dual luciferase reporter assay.

RESULTS

MiR-29a suppressed the expression and secretion of follistatin-like 1 in bone marrow-derived mesenchymal stem cells. Overexpression of follistatin-like 1 in bone marrow-derived mesenchymal stem cells decreased apoptosis of myocytes induced by hypoxia-reoxygenation. Cell apoptosis in myocytes was promoted by conditioned medium from bone marrow-derived mesenchymal stem cells with ectopic miR-29a expression. Conditioned medium of miR-29a-overexpressing bone marrow-derived mesenchymal stem cells inhibited the JAK2/STAT3 pathway in myocytes to promote apoptosis of myocytes.

CONCLUSIONS

MiR-29a in bone marrow-derived mesenchymal stem cells inhibits follistatin-like 1 secretion and promotes myocyte apoptosis by suppressing the JAK2/STAT3 pathway in hypoxia-reoxygenation injury.

Increasing the Efficacy of Stem Cell Therapy via Triple-Function Inorganic Nanoparticles

Stem cell therapy in heart disease is challenged by mis-injection, poor survival, and low cell retention. Here, we describe a biocompatible multifunctional silica-iron oxide nanoparticle to help solve these issues. The nanoparticles were made via an in situ growth of Fe₃O₄ nanoparticles on both the external surfaces and pore walls of mesocellular foam silica nanoparticles. In contrast to previous work, this approach builds a magnetic moiety inside the pores of a porous silica structure. These materials serve three roles: drug delivery, magnetic manipulation, and imaging. The addition of Fe₃O₄ to the silica nanoparticles increased their colloidal stability, T₂-based magnetic resonance imaging contrast, and superparamagnetism. We then used the hybrid materials as a sustained release vehicle of insulin-like growth factor-a pro-survival agent that can increase cell viability. In vivo rodent studies show that labeling stem cells with this nanoparticle increased the efficacy of stem cell therapy in a ligation/reperfusion model. The nanoparticle-labeled cells increase the mean left ventricular ejection fraction by 11 and 21% and the global longitudinal strain by 24 and 34% on days 30 and 60, respectively. In summary, this multifunctional nanomedicine improves stem cell survival via the sustained release of pro-survival agents.