Organ preservation remains a critical challenge in transplantation, primarily due to hypothermia-induced oxidative stress and metabolic dysfunction. Here, we report a mitochondria-enriched, cell-free preservation strategy by supplementing standard preservation solutions with freshly isolated mitochondria derived from human induced pluripotent stem cell-mesenchymal stem cells (MSC-mt). MSC-mt retained intact ultrastructure and functional biophysical properties. In vitro, MSC-mt were internalized by hepatocyte- and kidney-derived cells, reduced oxidative stress, preserved ATP levels, and attenuated apoptosis under cold stress. Ex vivo, MSC-mt improved liver preservation in University of Wisconsin (UW) solution, reducing sinusoidal edema, apoptosis, ALT/AST release, MDA accumulation, and oxidative DNA damage while enhancing SOD activity and preserving mitochondrial content. Human-specific mitochondrial signals remained detectable within preserved hepatic tissue. In a warm reoxygenation model, MSC-mt enhanced ATP recovery and reduced tissue injury and oxidative damage following cold storage. In kidneys, MSC-mt provided stronger protection than fibroblast- or adipose-derived mitochondria across both HC-A and UW solutions. Mechanistically, MSC-mt showed higher total and phosphorylated PINK1 levels and greater Parkin co-localization than fibroblast-derived mitochondria, while mitophagy inhibition partially reversed their antioxidant effects. These findings establish MSC-mt as a cell-free mitochondrial strategy for improving hypothermic organ preservation.

Cardiac fibrosis post-myocardial infarction (MI) induces adverse cardiac remodeling, ultimately resulting in heart failure. Exosomes (EXOs) derived from mesenchymal stem cells (MSCs) have emerged as potent modulators of post-infarction remodeling, capable of limiting fibrotic responses. Our previous study showed that growth differentiation factor 15 as pretreatment promoted the protective effects of MSCs against myocardial fibrosis post-MI via paracrine actions. We investigated whether exosomes derived from GDF15-treated iPSC-MSCs (GDF15-iPSC-MSC-EXOs) could alleviate post-MI fibrosis and further explored the mechanistic pathways underlying their effects. In a mouse model of MI, EXOs released from iPSC-MSCs and GDF15-treated iPSC-MSCs were collected from culture supernatants and subsequently administered intramuscularly around the infarct area. Cardiac fibrosis was assessed by Masson's trichrome staining. A collagen synthesis model in mouse cardiac fibroblasts (mCFs) was established by transforming growth factor-β1 (TGF-β1) treatment in vitro. The mitochondrial morphology of mCFs under TGF-β1 stimulation was evaluated by Mitotracker staining. Delivery of EXOs from GDF15-treated iPSC-MSCs resulted in less fibrotic remodeling and better ventricular function after MI than exosomes from untreated cells. In TGF-β1-stimulated fibroblasts, both exosome types reduced fibrosis markers by preventing mitochondrial fission, with GDF15-iPSC-MSC-EXOs affording stronger protection. These effects were partly attenuated in the presence of the mitochondrial fission activator FCCP. Mechanistically, GDF15, which is rich in GDF15-iPSC-MSC-EXOs, inhibited TGF-β1-induced mCF activation via repression of the MFAP4/ERK/Drp1 pathway through a direct physical interaction with MFAP4. GDF15 conditioning strengthened the capacity of iPSC-MSC-derived exosomes to mitigate cardiac fibrosis following MI via inhibition of mitochondrial fragmentation in CFs by repressing the MFAP4/ERK/Drp1 pathway. GDF15 pretreatment is a novel strategy to enhance the cardioprotection of iPSC-MSC-EXOs against cardiac fibrosis post-MI.

Mitochondria are nanoscale organelles essential for cellular metabolism and redox regulation, making them a compelling target for regenerative therapeutics. Analysis of wound-edge tissues from pediatric patients with chronic non-healing ulcers revealed marked metabolic insufficiency and impaired regenerative signaling, underscoring an unmet clinical need for mitochondrial-based interventions. Here, we show that topically applied mesenchymal stem cell-derived mitochondria (MSC-mt), functioning as naturally derived nanoscale organelles, markedly accelerate wound closure in a murine full-thickness skin injury model. MSC-mt enhanced angiogenesis, collagen deposition, and fibroblast survival while reducing oxidative stress and apoptosis. Mechanistically, their cytoprotective effects occur primarily through extracellular scavenging of reactive oxygen species (ROS), independent of cellular internalization. Excessive immobilization of MSC-mt within a thermosensitive hydrogel compromised their efficacy, emphasizing the importance of mitochondrial mobility and microenvironmental access. Under high oxidative stress, internalized MSC-mt activated PINK1-Parkin-mediated mitophagy, indicating a context-dependent intracellular quality-control response. These findings position MSC-mt as a cell-free, organelle-level nano-therapeutic that operates through a dual extracellular-intracellular mechanism and emphasize the importance of delivery strategies that preserve mitochondrial functionality and spatial freedom.

Idiopathic pulmonary fibrosis (IPF) is a serious and progressive lung disease characterized by devastating and progressive fibrosis. Treatment is unsatisfactory. There is accumulating evidence that transplantation of mesenchymal stem cell derived exosomes (MSC-EXOs) protects against IPF. This study aimed to investigate the protective effects of EXOs isolated from human induced pluripotent stem cell-derived MSCs (iPSC-MSC-EXOs) on pulmonary fibrosis and explore the underlying mechanisms. Exosomes were isolated from bone marrow-MSCs (BM-MSCs) and iPSC-MSCs and subsequently identified. A mouse model of pulmonary fibrosis was established by tracheal injection of bleomycin (BLM) followed by transplantation of BM-MSC-EXOs or iPSC-MSC-EXOs via tail vein injection. Pulmonary function and fibrosis were assessed by pulmonary function tests (PFT) and Masson trichrome staining, respectively. Mice lung fibroblasts (LFs) were treated with BM-MSC-EXOs or iPSC-MSC-EXOs in the presence of TGF-β1 in vitro. Compared with BM-MSC-EXOs, iPSC-MSC-EXO treatment significantly enhanced pulmonary function and decreased the fibrosis and lactate level in a mouse model of BLM-induced pulmonary fibrosis. In vitro, iPSC-MSC-EXOs exerted a superior protective efficacy against TGF-β1-induced LF activation via downregulation of the lactate level. Further analysis revealed a higher protein level of TRIM31 in iPSC-MSC-EXOs than BM-MSC-EXOs. Mechanistically, exosomal TRIM31 from iPSC-MSC-EXOs inhibited LF activation via downregulation of glycolysis by mediating ubiquitination of hexokinase 2 (HK2). Furthermore, knockdown of TRIM31 reduced the protective effects of iPSC-MSC-EXOs on pulmonary fibrosis in BLM-treated mice. Our study showed that TRIM31 delivered by iPSC-MSC-EXOs exerted anti-pulmonary fibrotic effects by alleviating LF activation via regulation of HK2 ubiquitination. This study provides a potential therapeutic strategy for patients with IPF.

BACKGROUND:Mitochondrial dysfunction plays an important role in the development of doxorubicin-induced cardiomyopathy (DIC). Mitochondrial transplantation (MT) exerts beneficial effects on multiple cardiovascular diseases. OBJECTIVE:This study aimed to determine whether transplantation of exogenous mitochondria derived from induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSC-Mito) could protect against DIC in mice and explore the potential molecular mechanisms. METHODS:Mitochondria were isolated from iPSC-MSCs using ultracentrifugation, then characterized by transmission electron microscopy and Western blotting. The cellular senescence of neonatal mouse cardiomyocytes (NMCMs) was examined by senescence-associated-β-galactosidase assay. Mitochondrial function in doxorubicin (DOX)-treated NMCMs exposed to different treatments was evaluated by seahorse assay. A mouse model of DIC was induced by intraperitoneal injection of DOX followed by intraperitoneal injection of iPSC-MSC-Mito. Cardiac function, fibrosis and cardiomyocyte senescence in each group was examined. RESULTS:The isolated iPSC-MSC-Mito exhibited intact mitochondrial morphology and quality. In vitro, iPSC-MSC-Mito could be internalized by NMCMs under DOX challenge. Administration of iPSC-MSC-Mito improved the respiratory capacity of cardiomyocytes under DOX challenge, due to downregulated lactate level, leading to inhibition of cardiomyocyte senescence. This effect was partially abrogated by exogenous lactate. Utilizing molecular docking and site-directed mutation assays, we found that lactate regulated SIRT2 expression by binding to the ARG97 and HIS187 residues in the PH domain of SIRT2. In vivo, transplantation of iPSC-MSC-Mito functionally attenuated DIC, manifested as improved cardiac function and decreased cardiac fibrosis and cardiomyocyte senescence. CONCLUSIONS:Transplantation of mitochondria isolated from iPSC-MSCs improved cardiac function in a mouse model of DIC by alleviating cardiomyocyte senescence via improved metabolic function. This may offer a novel therapeutic strategy for DIC.

This article discusses the study by Xiao et al, which investigated the therapeutic efficacy of serum-free cultured human umbilical cord mesenchymal stem cells (N-hUCMSCs) in a mouse model of knee osteoarthritis. The results showed that N-hUCMSCs alleviated osteoarthritis-related cartilage damage and inflammation comparably to both serum-cultured hUCMSCs and hyaluronic acid. While these findings broaden the potential clinical utility of N-hUCMSCs by circumventing certain drawbacks of serum-based cultures, the equivalence in efficacy raises important questions. First, how do N-hUCMSCs differ phenotypically from serum-cultured hUCMSCs, particularly in terms of proliferation rate, replicative capacity, and senescence profile? Second, what advantages might N-hUCMSCs offer over hyaluronic acid - a well-established therapy - beyond avoiding xenogeneic components and ethical concerns? Future research should focus on long-term phenotypic stability, sustained functional benefits, safety profiles, and mechanistic insights to ascertain whether N-hUCMSCs can surpass current standards of care.

The rise of radioresistance in treating cutaneous melanoma challenges the efficacy of radiotherapy. Transcriptomic sequencing highlights PURPL as one of the top upregulated long noncoding RNAs in response to ionizing radiation (IR) treatment in melanoma cells, suggesting its role in radioresistance. To explore such hypothesis, loss-of-function experiments were conducted to assess the impact of PURPL on melanoma cell viability, colony formation, and migration. Mechanistic studies using RNA pulldown identified BID as the interacting protein partner of PURPL. Further analysis explored the relationship among PURPL, BID, and Caspase-8 in the context of IR-induced DNA damage and apoptosis through loss-of- and gain-of-function experiments. The findings demonstrated that silencing PURPL significantly repressed melanoma cell viability, colony formation, migration, and invasiveness, indicating its potential role in promoting radioresistance. Moreover, PURPL was shown to repress IR-induced DNA damage and apoptosis, supporting its involvement in melanoma radioresistance. Mechanistically, PURPL inhibited the interaction between BID and Caspase-8, thereby modulating the mitochondrial apoptosis pathway and promoting radioresistance. In conclusion, this study provides evidence supporting the pro-radioresistance role of PURPL in melanoma. In vivo assays further corroborated the in vitro findings, highlighting the potential clinical relevance of targeting PURPL in radioresistant melanoma. By interfering with the association between BID and Caspase-8, PURPL may serve as a novel therapeutic target for clinical radiotherapy during the treatment of melanoma.

Background Mesenchymal stem cells (MSCs) require priming by proinflammatory stimuli for optimal immunosuppressive effects. Our previous work identified mixed lymphocyte reaction-conditioned medium (MLR-CdM) as a potent enhancer of MSC immunosuppressive properties. This study evaluates the immunomodulatory potential of MSC-derived extracellular vesicles preconditioned with MLR-CdM (MSC-EVMLR) compared to IFN-γ (MSC-EVIFN), focusing on key miRNAs and mechanisms involved. Methods We assessed the ability of MSC-EVMLR and MSC-EVIFN to modulate lymphocyte proliferation and cytokine expression in vitro. To identify potential effector molecules within MSC-EVMLR, we performed miRNA array analysis combined with dose-response experiments using MLR-CdM under varying stimulation conditions. We used a murine allogeneic heterotopic heart transplantation model to investigate the impact of MSC-EVMLR on graft survival and its immunomodulatory effects. Results MSC-EVMLR outperformed MSC-EVIFN in suppressing lymphocyte proliferation and steering cytokine expression toward an anti-inflammatory profile in vitro. Through miRNA array analysis and dose-response experiments with MLR-CdM, miR-638 was identified as a potential effector molecule in MSC-EVMLR. In vivo study demonstrated that MSC-EVMLR significantly prolonged graft survival, which was associated with a marked decreased proinflammatory cytokines IL6 and IFN-γ and increase in regulatory T cells (Tregs) and within the transplanted heart tissue. These effect was significantly reduced upon miR-638 knockdown. Additionally, the miR-638/Fosb axis was identified as a key pathway that promoted Treg differentiation and induced immune tolerance. Conclusions Preconditioning MSCs with MLR-CdM, a blend of inflammatory stimuli, potentiates the immunoregulatory capacity of MSC-EV beyond the effects of IFN-γ stimulation alone. This study advances the understanding of MSC-EV-based therapies in transplantation.

Cardiovascular diseases (CVDs) remain a global health concern, prompting ongoing research into novel contributors to their pathogenesis. Due to the proximity of the coronary arteries and the myocardium in epicardial adipose tissue (EAT) and pericardial adipose tissue (PAT), these tissues have emerged as key areas of interest for their potential influence on cardiac function and vascular health. This review synthesizes current research on the physiological and biological characteristics of EAT and PAT, exploring their composition and clinical measurement approaches. The roles of EAT and PAT in coronary artery disease (CAD), atrial fibrillation, and heart failure are discussed, and the contributions of EAT and PAT to these cardiovascular conditions are highlighted alongside their potential as therapeutic targets.

This article comments on the study by Zhang et al, which proposed that exosomes derived from hypoxia-injured endometrial epithelial cells promote human umbilical cord mesenchymal stem cell migration and differentiation into endometrial epithelial cells via exosomal miR-137-3p. The authors demonstrated that miR-137-3p targets ubiquitin protein ligase E3C and activates signal transducer and activator of transcription 3 signaling, thereby driving epithelial lineage transition. While this study expands our understanding of exosome-mediated intercellular communication in endometrial repair, several key gaps remain. Notably, microRNA (miRNA) profiling was performed in human umbilical cord mesenchymal stem cells post-exosome treatment, not in the exosomes derived from hypoxia-injured endometrial epithelial cell themselves, leaving open whether miR-137-3p is directly transferred or indirectly induced. In addition, data on exosome characterization were unavailable, and the rationale for selecting miR-137-3p over other differentially expressed miRNAs was not well justified. Future studies should include direct exosomal miRNA content analysis, in vivo validation, and deeper mechanistic exploration of the ubiquitin protein ligase E3C-signal transducer and activator of transcription 3 ubiquitination axis to establish the clinical and biological relevance of this pathway.

This article comments on the study by Fang, which demonstrates that reduced nuclear factor erythroid-derived 2 (NRF2) activity promotes endoplasmic reticulum stress and senescence in adipose-derived mesenchymal stem cells from hypertrophic obese mice, primarily through downregulation of mitofusin-2 (MFN2). Robust methodologies, including knockdown/rescue experiments, chromatin immunoprecipitation quantitative polymerase chain reaction, co-immunoprecipitation, and transplantation assays, substantiate that NRF2 or MFN2 disruption impairs the therapeutic potential of these cells in insulin resistance. However, the proposed MFN2-binding immunoglobulin protein interaction remains indirectly supported and requires biochemical validation (e.g., glutathione S-transferase pull-down/Forster resonance energy transfer/cross-linking mass spectrometry). Moreover, NRF2 may influence endoplasmic reticulum stress and senescence through additional unexplored targets. Future studies should clarify the structural and functional nature of the MFN2-binding immunoglobulin protein relationship and its implications for mitochondrial dynamics, endoplasmic reticulum-mitochondria tethering, and calcium signaling.

NOD-like receptor thermal protein domain associated protein 3 (NLRP3)-mediated pyroptosis of cardiomyocytes is a key contributor to the progression of myocardial infarction (MI). This study aimed to investigate whether exosomes derived from human induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSC-EXOs) could protect against MI by inhibiting cardiomyocyte pyroptosis and explore the underlying mechanisms. Exosomes from human bone marrow-MSCs (BM-MSC-EXOs) and iPSC-MSCs (iPSC-MSC-EXOs) were collected and intramuscularly injected into the peri-infarct region of a mouse MI model. Cardiac function was assessed four weeks post-injection. Myocardial pyroptosis was evaluated using TUNEL staining and measurement of associated factors. Neonatal mouse cardiomyocytes (NMCMs) exposed to serum deprivation and hypoxia (SD/H) were treated with BM-MSC-EXOs or iPSC-MSC-EXOs. A loss-of-function approach was employed to examine the role of iPSC-MSC-exosomal-miR-202-5p in regulating cardiomyocyte pyroptosis. Compared to BM-MSC-EXOs, iPSC-MSC-EXOs demonstrated superior improvement in cardiac function in MI mice. Both BM-MSC-EXOs and iPSC-MSC-EXOs reduced cardiomyocyte pyroptosis by downregulating proteins NLRP3, ASC, Caspase-1, and gasdermin D-NT, as well as inflammatory factors in MI mice and SD/H-treated NMCMs. iPSC-MSC-EXOs exhibited greater protective effects. MicroRNA sequencing revealed higher levels of miR-202-5p in iPSC-MSC-EXOs than in BM-MSC-EXOs. The protective effect of iPSC-MSC-EXOs against cardiomyocyte pyroptosis was partially reversed by miR-202-5p knockdown. Mechanistically, miR-202-5p in iPSC-MSC-EXOs inhibited cardiomyocyte pyroptosis by downregulating the TRAF3IP2/JNK pathway. iPSC-MSC-EXOs protect against MI by inhibiting cardiomyocyte pyroptosis via miR-202-5p-mediated suppression of the TRAF3IP2/JNK axis. These findings suggest a promising therapeutic approach for MI.

Metachromatic leukodystrophy (MLD) is an inherited disease caused by a deficiency of the enzyme arylsulfatase A (ARSA). Lentivirus-modified autologous hematopoietic stem cell gene therapy (HSCGT) has recently been approved for clinical use in pre and early symptomatic children with MLD to increase ARSA activity. Unfortunately, this advanced therapy is not available for most patients with MLD who have progressed to more advanced symptomatic stages at diagnosis. Patients with late-onset juvenile MLD typically present with a slower neurological progression of symptoms and represent a significant burden to the economy and healthcare system, whereas those with early onset infantile MLD die within a few years of symptom onset. We conducted a pilot study to determine the safety and benefit of HSCGT in patients with postsymptomatic juvenile MLD and report preliminary results. The safety profile of HSCGT was favorable in this long-term follow-up over 9 years. The most common adverse events (AEs) within 2 months of HSCGT were related to busulfan conditioning, and all AEs resolved. No HSCGT-related AEs and no evidence of distorted hematopoietic differentiation during long-term follow-up for up to 9.6 years. Importantly, to date, patients have maintained remarkably improved ARSA activity with a stable disease state, including increased Functional Independence Measure (FIM) score and decreased magnetic resonance imaging (MRI) lesion score. This long-term follow-up pilot study suggests that HSCGT is safe and provides clinical benefit to patients with postsymptomatic juvenile MLD.

The clinical application of mesenchymal stem cells (MSCs) in myocardial infarction (MI) is severely hampered by their poor survival. Pretreatment is a key strategy that has been adopted to promote their therapeutic efficacy. This study aimed to investigate the benefit of growth differentiation factor 15-pretreated MSCs (GDF15-MSCs) in enhancing cardiac repair following MI and to determine the underlying mechanisms. MSCs with or without GDF15 pretreatment were exposed to serum deprivation and hypoxia (SD/H) challenge. Apoptosis of MSCs was assessed by TUNEL staining. The conditioned media (CM) of MSCs and GDF15-MSCs was collected by centrifugation. MSCs and GDF15-MSCs were transplanted into the peri-infarct region in a mouse model of MI. Cardiac function, fibrosis and MSC survival were examined 4 weeks after MSC transplantation. Pretreatment with GDF15 greatly reduced SD/H-induced apoptosis of MSCs via inhibition of reactive oxygen species (ROS) generation by attenuating mitochondrial fission. Mechanistically, GDF15 pretreatment ameliorated mitochondrial fission of MSCs under SD/H challenge by activating the AMPK pathway. These effects were partially abrogated by AMPK inhibitor. Pretreatment with GDF15 also promoted paracrine effects of MSCs in vitro, evidenced by improving tube formation of HUVECs, and inhibited the apoptosis of cardiomyocytes induced by SD/H. At 4 weeks after transplantation, compared with MSCs, GDF15 pretreatment strongly promoted the survival of MSCs in the ischemic heart with consequent enhanced cardiac function, reduced cardiac fibrosis and increased angiogenesis. Our study showed that pretreatment with GDF15 promoted the cardioprotective effects of MSCs in MI via regulation of pro-survival signaling and paracrine actions. GDF15 pretreatment is an effective approach to enhance the therapeutic efficacy of MSCs in ischemic heart disease.

Bone regeneration is a multifaceted process involving the well-coordinated interaction of cellular functions such as the regulation of inflammation, the formation of new blood vessels, and the development of bone tissue. Bone regeneration is a multifaceted process involving the well-coordinated interplay of multiple cellular activities, such as inflammation control, blood vessel and bone tissue. Zhang et al developed a multifunctional hydrogel system embedded with bone marrow stromal cell-derived exosomes to address the challenges of large bone defects. This innovative approach demonstrated the dual-role capability of bone marrow stromal cell-derived exosomes in directing cell fate by significantly enhancing both angiogenesis and osteogenic differentiation in vitro. The hydrogel system effectively promoted the polarization of macrophages towards the anti-inflammatory M2 phenotype, fostering an environment that supports bone repair. The effectiveness of this hydrogel was validated in a murine fracture model, which promoted significant bone regeneration and functional vascularization. Despite compelling evidence, this study highlights areas for further investigation, including detailed descriptions of experimental procedures, control group selection, long-term outcomes, and the evaluation of inflammation status in vivo. Addressing these limitations will enhance the robustness and impact of the findings.

Abstract Background Numerous studies have confirmed the involvement of extracellular vesicles (EVs) in various physiological processes, including cellular death and tissue damage. Recently, we reported that EVs derived from ischemia-reperfusion heart exacerbate cardiac injury. However, the role of EVs from healthy heart tissue (heart-derived EVs, or cEVs) on myocardial ischemia-reperfusion (MI/R) injury remains unclear. Results Here, we demonstrated that intramyocardial administration of cEVs significantly enhanced cardiac function and reduced cardiac damage in murine MI/R injury models. cEVs treatment effectively inhibited ferroptosis and maintained mitochondrial homeostasis in cardiomyocytes subjected to ischemia-reperfusion injury. Further results revealed that cEVs can transfer ATP5a1 into cardiomyocytes, thereby suppressing mitochondrial ROS production, alleviating mitochondrial damage, and inhibiting cardiomyocyte ferroptosis. Knockdown of ATP5a1 abolished the protective effects of cEVs. Furthermore, we found that the majority of cEVs are derived from cardiomyocytes, and ATP5a1 in cEVs primarily originates from cardiomyocytes of the healthy murine heart. Moreover, we demonstrated that adipose-derived stem cells (ADSC)-derived EVs with ATP5a1 overexpression showed much better efficacy on the therapy of MI/R injury compared to control ADSC-derived EVs. Conclusions These findings emphasized the protective role of cEVs in cardiac injury and highlighted the therapeutic potential of targeting ATP5a1 as an important approach for managing myocardial damage induced by MI/R injury.

Although mitochondrial aldehyde dehydrogenase 2 (ALDH2) is involved in aging and aging-related diseases, its role in the regulation of human mesenchymal stem cell (MSC) senescence has not been investigated. This study aimed to determine the role of ALDH2 in regulating MSC senescence and illustrate the potential mechanisms. MSCs were isolated from young (YMSCs) and aged donors (AMSCs). Senescence-associated β-galactosidase (SA-β-gal) staining and Western blotting were used to assess MSC senescence. Reactive oxygen species (ROS) generation and mitochondrial membrane potential were determined to evaluate mitochondrial function. We showed that the expression of ALDH2 increased alongside cellular senescence of MSCs. Overexpression of ALDH2 accelerated YMSC senescence whereas down-regulation alleviated premature senescent phenotypes of AMSCs. Transcriptome and biochemical analyses revealed that an elevated ROS level and mitochondrial dysfunction contributed to ALDH2 function in MSC senescence. Using molecular docking, we identified interferon regulatory factor 7 (IRF7) as the potential target of ALDH2. Mechanistically, ectopic expression of ALDH2 led to mitochondrial dysfunction and accelerated senescence of MSCs by increasing the stability of IRF7 through a direct physical interaction. These effects were partially reversed by knockdown of IRF7. These findings highlight a crucial role of ALDH2 in driving MSC senescence by regulating mitochondrial homeostasis, providing a novel potential strategy against human aging-related diseases.

Doxorubicin (DOX) is a chemotherapeutic agent widely used for tumor treatment. Nonetheless its clinical application is heavily limited by its cardiotoxicity. There is accumulated evidence that transplantation of mesenchymal stem cell-derived exosomes (MSC-EXOs) can protect against Dox-induced cardiomyopathy (DIC). This study aimed to examine the cardioprotective effects of EXOs isolated from human induced pluripotent stem cell-derived MSCs (iPSC-MSCs) against DIC and explore the potential mechanisms. EXOs were isolated from the cultural supernatant of human BM-MSCs (BM-MSC-EXOs) and iPSC-MSCs (iPSC-MSC-EXOs) by ultracentrifugation. A mouse model of DIC was induced by intraperitoneal injection of Dox followed by tail vein injection of PBS, BM-MSC-EXOs, or iPSC-MSC-EXOs. Cardiac function, cardiomyocyte senescence and mitochondrial dynamics in each group were assessed. In vitro, neonatal mouse cardiomyocytes (NMCMs) were subjected to Dox and treated with BM-MSC-EXOs or iPSC-MSC-EXOs. The mitochondrial morphology and cellular senescence of NMCMs were examined by Mitotracker staining and senescence-associated-β-galactosidase assay, respectively. Compared with BM-MSC-EXOs, mice treated with iPSC-MSC-EXOs displayed improved cardiac function and decreased cardiomyocyte mitochondrial fragmentation and senescence. In vitro, iPSC-MSC-EXOs were superior to BM-MSC-EXOs in attenuation of cardiomyocyte mitochondrial fragmentation and senescence caused by DOX. MicroRNA sequencing revealed a higher level of miR-9-5p in iPSC-MSC-EXOs than BM-MSC-EXOs. Mechanistically, iPSC-MSC-EXOs transported miR-9-5p into DOX-treated cardiomyocytes, thereby suppressing cardiomyocyte mitochondrial fragmentation and senescence via regulation of the VPO1/ERK signal pathway. These protective effects and cardioprotection against DIC were largely reversed by knockdown of miR-9-5p in iPSC-MSC-EXOs. Our results showed that miR-9-5p transferred by iPSC-MSC-EXOs protected against DIC by alleviating cardiomyocyte senescence via inhibition of the VPO1/ERK pathway. This study offers new insight into the application of iPSC-MSC-EXOs as a novel therapeutic strategy for DIC treatment.

Apelin is an endogenous ligand for the Apelin receptor and is a critical protective effector in myocardial infarction (MI). Nevertheless, these protective mechanisms are not fully understood. Ferroptosis is the major driving factor of MI. This study aimed to investigate the effects and underlying regulatory mechanisms of Apelin on cardiomyocyte ferroptosis in MI. A model of MI was induced in adult C57BL/6J wild type (WT) and Apelin knockout (Apelin-/-) mice. Cardiac function was examined by echocardiography 4 weeks post-MI. RNA-seq, histochemical analyses, and Western blotting were applied to examine the effects of Apelin knockout on the transcriptome and pathological remodeling following infarction and the molecular mechanisms. Mice neonatal cardiomyocytes (NCMs) were used to establish the serum deprivation/hypoxia (SD/H) model in vitro. Compared with WT mice, Apelin-/- mice exhibited more severe impairment of cardiac function and increased fibrosis following infarction. Transcriptome and biochemical analyses revealed the involvement of ferroptosis in mediating Apelin function in MI. Ferroptosis-related proteins were significantly increased post-MI in Apelin-/- mice whereas p-AMPK was greatly decreased. Apelin treatment activated the AMPK pathway and thereby inhibited ferroptosis of NCMs induced by SD/H in vitro. These protective effects were partially reversed by AMPK inhibitor. Apelin deficiency aggravated cardiac dysfunction following infarction by activating cardiomyocyte ferroptosis via inhibition of the AMPK pathway. This offers a novel potential therapeutic target for MI treatment.

In the elderly population, coronary heart disease (CHD) often coexists with hypertension. However, excessive blood pressure reduction can paradoxically increase the incidence of adverse events. Understanding the molecular mechanisms underlying hypertension and CHD in aged populations is crucial for developing targeted therapies and improving clinical outcomes. In this study, we constructed myocardial infarction (MI) and transverse aortic constriction (TAC) modelsY in aged mice to simulate the disease states of CHD and hypertension, respectively. Using integrated proteomic and phosphoproteomic analyses, we investigated the molecular signatures associated with MI and TAC in these models. Our aim was to identify key molecules involved in these conditions and to understand their unique and shared characteristics. Through our comprehensive proteomic and phosphoproteomic analysis, we identified a total of 1583 proteins and 232 phosphorylated proteins. We observed significant upregulation of heart disease markers such as Myh7, Xirp2, and Acta1, indicating the successful establishment of the MI and TAC models. The overlapped differentially expressed proteins (DEPs) and differentially phosphorylated proteins (DPPs) in MI and TAC were involved in heart failure-related processes including cardiac muscle contraction and hypertrophic cardiomyopathy, further supporting the validity of the models. Among the DEPs, Ppme1 was upregulated in the TAC model but downregulated in the MI model, while Sec31a and Gm56451 displayed the opposite expression patterns. Among the DPPs, Ablim1 and Atp2a2 were found to be significantly upregulated in the TAC model, whereas their expression was markedly reduced in the MI model. In addition, five other DPPs, including REV_Q3TAY5, Cbx3, PITPNB, Eif4b, and A0A1Y7VP73, were elevated in the MI model but decreased in the TAC model. In conclusion, these findings suggest that MI and TAC not only share certain molecular features but also retain their unique characteristics, providing potential biomarkers and therapeutic targets.