Human UC-MSC-derived exosomes facilitate ovarian renovation in rats with chemotherapy-induced premature ovarian insufficiency

Targeting capabilities of engineered extracellular vesicles for the treatment of neurological diseases

Recent advances in research on extracellular vesicles have significantly enhanced their potential as therapeutic agents for neurological diseases. Owing to their therapeutic properties and ability to cross the blood-brain barrier, extracellular vesicles are recognized as promising drug delivery vehicles for various neurological conditions, including ischemic stroke, traumatic brain injury, neurodegenerative diseases, glioma, and psychosis. However, the clinical application of natural extracellular vesicles is hindered by their limited targeting ability and short clearance from the body. To address these limitations, multiple engineering strategies have been developed to enhance the targeting capabilities of extracellular vesicles, thereby enabling the delivery of therapeutic contents to specific tissues or cells. Therefore, this review aims to highlight the latest advancements in natural and targeting-engineered extracellular vesicles, exploring their applications in treating traumatic brain injury, ischemic stroke, Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, glioma, and psychosis. Additionally, we summarized recent clinical trials involving extracellular vesicles and discussed the challenges and future prospects of using targeting-engineered extracellular vesicles for drug delivery in treating neurological diseases. This review offers new insights for developing highly targeted therapies in this field.

Hypoxic mesenchymal stem cell-derived exosomal circDennd2a regulates granulosa cell glycolysis by interacting with LDHA

BACKGROUND

Premature ovarian insufficiency (POI) is an ovarian dysfunction disorder that significantly impacts female fertility. Ovarian granulosa cells (GCs) are crucial somatic components supporting oocyte development that rely on glycolysis for energy production, which is essential for follicular growth. Hypoxia-induced exosomal circRNAs regulate glycolysis, but their biological functions and molecular mechanisms in POI are largely unexplored. The present comprehensive investigation revealed a substantial reduction in ovarian glycolysis levels in POI rats. Notably, hypoxia-induced exosomes originating from mesenchymal stem cells (HM-Exs) exhibit a remarkable capacity to enhance ovarian glycolysis, mitigate GCs apoptosis, reinstate disrupted estrous cycles, modulate sex hormone levels, and curtail the presence of atretic follicles. These restorative actions collectively contribute to fostering fertility revival in POI-afflicted rats.

METHODS

Cyclophosphamide was administered for 2 weeks to induce POI rat model, and POI rats were randomly divided into three groups and treated with PBS, NM-Exs and HM-Exs, respectively. Ovarian function and fertility were assessed at the end of the study and ovarian tissues were collected for analysis of energy metabolites. The relationship between circDennd2a and POI was explored in vitro by qRT-PCR, Western blotting, CCK-8 assay, EdU staining, TUNEL staining, extracellular acidification rate (ECAR) measurements, and ATP, lactate and pyruvate level assays.

RESULTS

Our findings revealed depletion of circDennd2a in serum samples and GCs from individuals suffering from POI. The introduction of HM-Exs-derived circDennd2a (HM-Exs-circDennd2a) effectively counteracted GCs apoptosis by enhancing glycolytic processes and driving cellular proliferation. CircDennd2a interacted with lactate dehydrogenase A (LDHA), which served as a catalyst to increase LDHA enzymatic activity and facilitate the conversion of NADH to NAD+. This biochemical cascade worked synergistically to sustain glycolytic function within GCs.

CONCLUSION

This study revealed that HM-Exs-circDennd2a promoted LDHA activity and enhanced GCs glycolytic capacity, both of which support its use as a potential clinical diagnostic and therapeutic target for POI.

Nicotinamide mononucleotide improves the ovarian reserve of POI by inhibiting NLRP3-mediated pyroptosis of ovarian granulosa cells

BACKGROUND

Premature ovarian insufficiency (POI) is a common clinical problem, but there is currently no effective treatment. NLRP3 inflammasome-induced pyroptosis is thought to be a possible mechanism of POI. Nicotinamide mononucleotide (NMN) has a certain anti-inflammatory effect, providing a promising approach for the treatment of POI.

METHODS

Thirty female Sprague Dawley rats were randomly divided into a control group (n = 10) and a POI group (n = 20). Cyclophosphamide (CTX) was administered for 2 weeks to induce POI. Then the POI group was divided into two groups: the CTX-POI group (n = 10), which was given saline; and the CTX-POI + NMN group (n = 10), which was given NMN at a dose of 500 mg/kg/day for 21 consecutive days. At the end of the study, the serum hormone concentrations of each group were determined, and each group was subjected to biochemical, histopathological, and immunohistochemical analyses. In the in vitro experiment, cell pyroptosis was simulated by using lipopolysaccharide (LPS) and nigricin (Nig), and then KGN cells were treated with NMN, MCC950, and AGK2, and the levels of Nicotinamide adenine dinucleotide (NAD+) and inflammatory factors Interleukin-18(IL-18) and Interleukin-1β(IL-1β) in the cell supernatants were detected, and the levels of pyroptosis-related factors in the cells were determined.

RESULTS

In POI rats, NMN treatments can improve blood hormone levels and partially improve the number of follicles, enhance ovarian reserve function and ovarian index.The evidence is that the increase in NAD+ levels and the activation of SIRT2 expression can reduce the expression of NLRP3, Gasdermin D (GSDMD), Caspase-1, IL-18, and IL-1β in the ovary.

CONCLUSION

NMN improves CTX-induced POI by inhibiting NLRP3-mediated pyroptosis, providing a new therapeutic strategy and drug target for clinical POI patients.

Human umbilical cord mesenchymal stem cell-derived extracellular vesicles harboring IGF-1 improve ovarian function of mice with premature ovarian insufficiency through the Nrf2/HO-1 pathway

OBJECTIVE

Premature ovarian insufficiency (POI) is a disease with medical, psychological and reproductive implications, but its common therapies have limited efficacy and a likelihood of complications. This study delves into the therapeutic role of human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUC-MSCs-EVs) in POI mice through the insulin-like growth factor 1 (IGF-1)/nuclear factor E2 related factor 2 (Nrf2)/heme oxygenase-1 (HO-1)/autophagy pathway.

METHODS

hUC-MSCs were transfected with lentiviral short hairpin RNA of IGF-1 before EV extraction. Cyclophosphamide (CTX)-induced POI mouse models were administrated with hUC-MSCs-EVs. Mouse ovarian granulosa cells (GCs) were induced with CTX, then treated with hUC-MSCs-EVs and ML385. Ovarian histopathological changes were observed, changes in follicle number at all levels were counted and serum sex hormones were evaluated, as well as LC3II/I and Beclin-1 expression. GCs were subject to detection of proliferation, deaths, oxidative stress, and Nrf2 nuclear translocation.

RESULTS

After CTX exposure, mice showed thinner GCs layer in the ovary, reduced number of GCs and follicles at all levels, disturbed serum sex hormones, enhanced oxidative stress and autophagy, and downregulated ovarian IGF-1; whereas, hUC-MSCs-EVs upregulated IGF-1 to improve the ovarian function. hUC-MSCs-EVs carrying IGF-1 activated Nrf2/HO-1 signaling to inhibit CTX-induced excessive autophagy of GCs, but this ameliorative effect was partially weakened by inhibiting Nrf2/HO-1 signaling. hUC-MSCs-EVs inhibited excessive autophagy of GCs and improved ovarian function of CTX-induced mice through IGF-1/Nrf2/HO-1 pathway.

CONCLUSION

hUC-MSCs-EVs activate the Nrf2/HO-1 signaling by carrying IGF-1, which in turn inhibits excessive autophagy and damage of GCs, thus improving ovarian function in POI mice.

Mesenchymal stem cell-derived extracellular vesicles therapy for primary ovarian insufficiency: a systematic review and meta-analysis of pre-clinical studies

BACKGROUND

Primary ovarian insufficiency (POI) manifests with hormonal imbalances, menstrual irregularities, follicle loss, and infertility. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are emerging as a promising treatment for POI. This systematic review aims to assess the effects of MSC-EVs on follicle number, hormonal profile, and fertility in POI animal models.

METHODS

A systematic search of PubMed, Scopus, and Web of Science databases up to December 14th, 2023 was conducted. Two reviewers independently conducted screening, risk of bias assessment, and data extraction. Meta-analysis was performed to analyze treatment versus control outcomes using a random effects model. Publication bias was assessed using Egger's regression test and sensitivity analysis was assessed using the leave-one-out method. Subgroup analyses and meta-regressions were conducted based on EV source, induction model, type of animal, study quality, administration route, administration frequency and route, and dose.

RESULTS

a total of 29 studies were included. MSC-EVs treatment significantly increased total follicle count (SMD, (95CI), p-value; 3.56, (0.91, 6.21), < 0.001), including primordial (SMD, (95CI), p-value; 2.86, (1.60, 4.12), < 0.001), primary (SMD, (95CI), p-value; 3.17, (2.28, 4.06), < 0.001), mature (SMD, (95CI), p-value; 2.26, (1.02, 3.50), < 0.001), and antral follicles (SMD, (95CI), p-value; 2.44, (1.21, 3.67), < 0.001). Administration frequency and route did not affect this outcome, but EV source affected primordial, primary, secondary and antral follicle count. Additionally, MSC-EVs treatment elevated anti-müllerian hormone (SMD, (95CI); 3.36, (2.14, 4.58)) and estradiol (SMD, (95CI); 3.19, (2.20, 4.17)) levels while reducing follicle stimulating hormone levels (SMD, (95CI); -2.68, (-4.42, -0.94)). Unlike EV source, which had a significant impact on all three hormones, administration frequency, route, and EV dose did not affect this outcome. Moreover, treatment increased offspring number (SMD, (95CI); 3.70, (2.17, 5.23)) and pregnancy odds (OR, (95CI); 10.25, (4.29, 24.46)) compared to controls. Publication bias and a high level of heterogeneity was evident in all analyses, except for the analysis of the pregnancy odds. However, sensitivity analysis indicated that all of the analyses were stable.

CONCLUSION

MSC-EVs therapy shows promise for POI treatment, potentially facilitating clinical translation. However, Further research is warranted to optimize methodology and assess side effects.

Stem cell-derived extracellular vesicles in premature ovarian failure: an up-to-date meta-analysis of animal studies

BACKGROUND

There has been a significant surge in animal studies of stem cell-derived extracellular vesicles (EVs) therapy for the treatment of premature ovarian failure (POF) but its efficacy remains unknown and a comprehensive and up-to-date meta-analysis is lacking. Before clinical translation, it is crucial to thoroughly understand the overall impact of stem cell-derived EVs on POF.

METHODS

PubMed, EMBASE, Cochrane Library, Web of Science were searched up to February 18, 2024. The risk of bias was evaluated according to Cochrane Handbook criteria, while quality of evidence was assessed using the SYRCLE system. The PRISMA guidance was followed. Trial sequential analysis was conducted to assess outcomes, and sensitivity analysis and publication bias analysis were performed using Stata 14.

RESULTS

Data from 25 studies involving 339 animals were extracted and analyzed. The analysis revealed significant findings: stem cell-derived EVs increase ovary weight (SMD = 3.88; 95% CI: 2.50 ~ 5.25; P < 0.00001; I2 = 70%), pregnancy rate (RR = 3.88; 95% CI: 1.94 ~ 7.79; P = 0.0001; I2 = 0%), count of births (SMD = 2.17; 95% CI: 1.31 ~ 3.04; P < 0.00001; I2 = 69%) and counts of different types of follicles. In addition, it elevates the level of AMH (SMD = 4.15; 95% CI: 2.75 ~ 5.54; P < 0.00001; I2 = 88%) and E2 (SMD = 2.88; 95% CI: 2.02 ~ 3.73; P < 0.00001; I2 = 80%) expression, while reducing FSH expression (SMD = -5.05; 95% CI: -6.60 ~ -3.50; P < 0.00001; I2 = 90%). Subgroup analysis indicates that the source of EVs, animal species, modeling method, administration route, and test timepoint affected efficacy. Trial sequential analysis showed that there was sufficient evidence to confirm the effects of stem cell-derived EVs on birth counts, ovarian weights, and follicle counts. However, the impact of stem cell-derived EVs on pregnancy rates needs to be further demonstrated through more animal experimental evidence.

CONCLUSIONS

Stem cell-derived EVs demonstrate safety and efficacy in treating POF animal models, with potential improvements in fertility outcomes.

TRIAL REGISTRATION

PROSPERO registration number: CRD42024509699.

Bone marrow mesenchymal stem cell-derived exosomes effectively ameliorate the outcomes of rats with acute graft-versus-host disease

Mesenchymal stem cells (MSCs) reveal multifaceted immunoregulatory properties, which can be applied for diverse refractory and recurrent disease treatment including acute graft-versus-host disease (aGVHD). Distinguishing from MSCs with considerable challenges before clinical application, MSCs-derived exosomes (MSC-Exos) are cell-free microvesicles with therapeutic ingredients and serve as advantageous alternatives for ameliorating the outcomes of aGVHD. MSC-Exos were enriched and identified by western blotting analysis, NanoSight, and transmission electron microscopy (TEM). Bone marrow-derived MSCs (denoted as MSCs) and exosomes (denoted as MSC-Exos) were infused into the aGVHD SD-Wister rat model via tail vein, and variations in general growth and survival of rats were observed. The level of inflammatory factors in serum was quantized by enzyme-linked immunosorbent assay (ELISA). The pathological conditions of the liver and intestine of rats were observed by frozen sectioning. The ratios of CD4+/CD8+ and Treg cell proportions in peripheral blood, together with the autophagy in the spleen and thymus, were analyzed by flow cytometry. After treatment with MSC-Exos, the survival time of aGVHD rats was prolonged, the clinical manifestations of aGVHD in rats were improved, whereas the pathological damage of aGVHD in the liver and intestine was reduced. According to ELISA, we found that MSC-Exos revealed ameliorative effect upon aGVHD inflammation (e.g., TNF-α, IL-2, INF-γ, IL-4, and TGF-β) compared to the MSC group. After MSC-Exo treatment, the ratio of Treg cells in peripheral blood was increased, whereas the ratio of CD4+/CD8+ in peripheral blood and the autophagy in the spleen and thymus was decreased. MSC-Exos effectively suppressed the activation of immune cells and the manifestation of the inflammatory response in the aGVHD rat model. Our data would supply new references for MSC-Exo-based "cell-free" biotherapy for aGVHD in future.

Ovarian fibrosis: molecular mechanisms and potential therapeutic targets

Ovarian fibrosis, characterized by the excessive proliferation of ovarian fibroblasts and the accumulation of extracellular matrix (ECM), serves as one of the primary causes of ovarian dysfunction. Despite the critical role of ovarian fibrosis in maintaining the normal physiological function of the mammalian ovaries, research on this condition has been greatly underestimated, which leads to a lack of clinical treatment options for ovarian dysfunction caused by fibrosis. This review synthesizes recent research on the molecular mechanisms of ovarian fibrosis, encompassing TGF-β, extracellular matrix, inflammation, and other profibrotic factors contributing to abnormal ovarian fibrosis. Additionally, we summarize current treatment approaches for ovarian dysfunction targeting ovarian fibrosis, including antifibrotic drugs, stem cell transplantation, and exosomal therapies. The purpose of this review is to summarize the research progress on ovarian fibrosis and to propose potential therapeutic strategies targeting ovarian fibrosis for the treatment of ovarian dysfunction.

Fertility protection: a novel approach using pretreatment with mesenchymal stem cell exosomes to prevent chemotherapy-induced ovarian damage in a mouse model

BACKGROUND

Primary ovarian insufficiency refers to the loss of ovarian function before the age of 40 years and leads to amenorrhea and infertility. Primary ovarian insufficiency has diverse causes, but a common cause is exposure to gonadotoxic chemotherapy used in cancer treatment. Because of the risk for developing primary ovarian insufficiency, patients who want to preserve their fertility may consider various procedures for fertility preservation. However, current fertility preservation options are highly invasive, carry substantial risks, and have uncertain success rates. Recent studies from our group and others reported that mesenchymal stem cells and mesenchymal stem cell-derived exosomes can restore ovarian function in preclinical models of primary ovarian insufficiency by restoring damaged cells and inhibiting apoptosis. Although the restorative effect of mesenchymal stem cell-derived exosomes has been well reported in previous studies, the potential of mesenchymal stem cell-derived exosomes in preventing ovarian damage has not been fully elucidated.

OBJECTIVE

This study hypothesized that the antiapoptotic potential of mesenchymal stem cell-derived exosomes may protect ovarian tissue from chemotherapy-induced damage.

STUDY DESIGN

In this study, we delivered mesenchymal stem cell-derived exosomes directly into the ovaries of mice before administration of chemotherapy. A total of 60 mice were divided into 3 groups (20 per group), which were labeled the control, chemotherapy, and fertility protection groups. Only the fertility protection group mice received exosomes, whereas the control and chemotherapy group mice received saline. After exosome injection, the chemotherapy and fertility protection groups of mice were subjected to chemotherapy to induce ovarian damage. After chemotherapy, we evaluated the protective effects of exosome treatment on ovarian function, such as estrous cyclicity, serum hormone levels, and the fertility rate, by comparing these outcomes between the chemotherapy and fertility protection groups. These outcomes were also compared with those of the control group for comparison with outcomes under healthy conditions.

RESULTS

After intraovarian injection of exosomes before chemotherapy, the mice were able to maintain their estrous cycle (4- to 5-day cyclicity), serum anti-müllerian hormone level (66.06±26.40 ng/mL, not significantly different from that of the healthy controls), folliculogenesis (32.2±11.3 in the chemotherapy group vs 46.4±14.1 in the fertility protection group; P<.05), expression of the steroidogenic acute regulatory protein gene (a the steroidogenesis marker) (0.44±0.11-fold expression in the chemotherapy group and 0.88±0.31-fold expression in the fertility protection group; P<.05), and fertility (2 of 8 in the chemotherapy group and 5 of 8 in the fertility protection group), thereby showing prevention of chemotherapy-induced damage. We found that exosome treatment before chemotherapy can preserve ovarian function and protect fertility through the overexpression of ATP synthase-binding cassette transporters, such as ABCB1b (10.17±17.75-fold expression in the chemotherapy group and 44.14±33.25-fold expression in the fertility protection group; P<.05) and ABCC10 (3.25±0.59-fold expression in the chemotherapy group and 5.36±1.86-fold expression in the fertility protection group; P<.05).

CONCLUSION

In this study, we present a novel fertility protection method using mesenchymal stem cell-derived exosomes. We concluded that mesenchymal stem cell-derived exosomes are a promising and simple treatment option for fertility protection in reproductive-aged patients who are receiving gonadotoxic chemotherapy.

Extracellular vesicles in nanomedicine and regenerative medicine: A review over the last decade

Small extracellular vesicles (sEVs) are known to be secreted by a vast majority of cells. These sEVs, specifically exosomes, induce specific cell-to-cell interactions and can activate signaling pathways in recipient cells through fusion or interaction. These nanovesicles possess several desirable properties, making them ideal for regenerative medicine and nanomedicine applications. These properties include exceptional stability, biocompatibility, wide biodistribution, and minimal immunogenicity. However, the practical utilization of sEVs, particularly in clinical settings and at a large scale, is hindered by the expensive procedures required for their isolation, limited circulation lifetime, and suboptimal targeting capacity. Despite these challenges, sEVs have demonstrated a remarkable ability to accommodate various cargoes and have found extensive applications in the biomedical sciences. To overcome the limitations of sEVs and broaden their potential applications, researchers should strive to deepen their understanding of current isolation, loading, and characterization techniques. Additionally, acquiring fundamental knowledge about sEVs origins and employing state-of-the-art methodologies in nanomedicine and regenerative medicine can expand the sEVs research scope. This review provides a comprehensive overview of state-of-the-art exosome-based strategies in diverse nanomedicine domains, encompassing cancer therapy, immunotherapy, and biomarker applications. Furthermore, we emphasize the immense potential of exosomes in regenerative medicine.

Mesenchymal stem cells derived from adipose tissue and umbilical cord reveal comparable efficacy upon radiation-induced colorectal fibrosis in rats

Chemoradiotherapy (CRT) and radiotherapy (RT) have served as anticancer treatments and neoadjuvant therapies for conquering multimodal rectal cancers including colorectal carcinoma (CRC), yet the concomitant radiation-induced colorectal fibrosis (RICF) has caused chronic toxicity and stenosis in the colorectal mucosa of patients. Mesenchymal stem/stromal cells (MSCs) with unique bidirectional immunoregulation and anti-fibrotic effect have been recognized as splendid sources for regenerative purposes including intestinal diseases. Herein, we are aiming to verify the feasibility and variations of MSC-based cytotherapy for the remission of RICF from the pathological features and the potential impact upon the transcriptomic signatures of RICF rats. For the purpose, we utilized our well-established RICF Sprague-Dawley (SD) rats by radiation for five weeks, and conducted consecutive intraperitoneal injection of two distinct MSCs for treatment, including MSCs derived from adult adipose tissue (AD-MSCs) and perinatal umbilical cord (UC-MSCs). On the one hand, the efficacy of AD-MSCs and UC-MSCs was assessed by diverse indicators, including weight change, pathological detections (e.g., H&E staining, Masson staining, EVG staining, IF staining, and IHC staining), and proinflammatory and fibrotic factor expression. On the other hand, we turned to RNA-sequencing (RNA-SEQ) and multifaceted bioinformatics analyses (e.g., GOBP, Venn Map, KEGG, and GSEA) to compare the impact of AD-MSC and UC-MSC treatment upon the gene expression profiling and genetic variations. RICF rats after consecutive AD-MSC and UC-MSC administration revealed comparable remission in histopathogenic features and significant suppression of diverse proinflammatory and fibrotic factors expression. Meanwhile, RICF rats after both MSC treatment revealed decrease and variations in the alterations in diverse gene expression and somatic mutations compared to RICF rats. Collectively, our data indicated the comparable therapeutic effect of AD-MSCs and UC-MSCs upon RICF in SD rats, together with the conservations in gene expression profiling and the diverse variations in genetic mutations. Our findings indicated the multifaceted impact of MSC infusion for the supervision of RICF both at the therapeutic and transcriptomic levels, which would provide novel references for the further evaluation and development of MSC-based regimens in future.

Model construction and drug therapy of primary ovarian insufficiency by ultrasound-guided injection

BACKGROUND

Clinically, hormone replacement therapy (HRT) is the main treatment for primary ovarian insufficiency (POI). However, HRT may increase the risk of both breast cancer and cardiovascular disease. Exosomes derived from human umbilical cord mesenchymal stem cell (hUC-MSC) have been gradually applied to the therapy of a variety of diseases through inflammation inhibition, immune regulation, and tissue repair functions. However, the application and study of hUC-MSC exosomes in POI remain limited.

METHODS

Here, we first constructed four rat animal models: the POI-C model (the "cyclophosphamide-induced" POI model via intraperitoneal injection), the POI-B model (the "busulfan-induced" POI model), the POI-U model (the "cyclophosphamide-induced" POI model under ultrasonic guidance), and MS model (the "maternal separation model"). Second, we compared the body weight, ovarian index, status, Rat Grimace Scale, complications, and mortality rate of different POI rat models. Finally, a transabdominal ultrasound-guided injection of hUC-MSC exosomes was performed, and its therapeuticy effects on the POI animal models were evaluated, including changes in hormone levels, oestrous cycles, ovarian apoptosis levels, and fertility. In addition, we performed RNA-seq to explore the possible mechanism of hUC-MSC exosomes function.

RESULTS

Compared with the POI-C, POI-B, and MS animal models, the POI-U model showed less fluctuation in weight, a lower ovarian index, fewer complications, a lower mortality rate, and a higher model success rate. Second, we successfully identified hUC-MSCs and their exosomes, and performed ultrasound-guided intraovarian hUC-MSCs exosomes injection. Finally, we confirmed that the ultrasound-guided exosome injection (termed POI-e) effectively improved ovarian hormone levels, the oestrous cycle, ovarian function, and fertility. Mechanically, hUC-MSCs may play a therapeutic role by regulating ovarian immune and metabolic functions.

CONCLUSIONS

In our study, we innovatively constructed an ultrasound-guided ovarian drug injection method to construct POI-U animal models and hUC-MSC exosomes injection. And we confirmed the therapeutic efficacy of hUC-MSC exosomes on the POI-U animal models. Our study will offer a better choice for new animal models of POI in the future and provides certain guidance for the hUC-MSCs exosome therapy in POI patients.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Ameliorate Aging-Induced BTB Impairment in Porcine Testes by Activating Autophagy and Inhibiting ROS/NLRP3 Inflammasomes via the AMPK/mTOR Signaling Pathway

As a pivotal player in spermatogenesis, the blood-testis barrier (BTB) made from junction apparatus coexisting in Sertoli cells (SCs) is impaired with an increase in age and ultimately induces spermatogenic dysfunction or even infertility. It has been corroborated that bone marrow mesenchymal stem cell (BMSC) transplantation can efficiently repair and regenerate the testicular function. As vital mediators of cell-to-cell communication, MSC-derived exosomes (Exos) can directly serve as therapeutic agents for tissue repair and regeneration. However, the therapeutic value of BMSC-Exos in aging-induced BTB damage remains to be confirmed. In this study, we explored that the old porcine testes had defective autophagy, which aggravated BTB disruption in SCs. BMSC-Exos could decrease ROS production and NLRP3 inflammasome activation but enhanced autophagy and tight junction (TJ) function in D-gal-triggered aging porcine SCs and mouse model testes, according to in vitro and in vivo experiments. Furthermore, rapamycin, NAC, MCC950, and IL-1Ra restored the TJ function in D-gal-stimulated aging porcine SCs, while BMSC-Exos' stimulatory effect on TJ function was inhibited by chloroquine. Moreover, the treatment with BMSC-Exos enhanced autophagy in D-gal-induced aging porcine SCs by means of the AMPK/mTOR signal transduction pathway. These findings uncovered through the present study that BMSC-Exos can enhance the BTB function in aging testes by improving autophagy via the AMPK/mTOR signaling pathway, thereby suppressing ROS production and NLRP3 inflammasome activation.

Protective role of stem cells in POI: Current status and mechanism of action, a review article

Premature ovarian insufficiency (POI) has far-reaching consequences on women's life quality. Due to the lack of full recognition of the etiology and complexity of this disease, there is no appropriate treatment for infected patients. Recently, stem cell therapy has attracted the attention of regenerative medicine scholars and offered promising outcomes for POI patients. Several kinds of stem cells, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) have been used for the treatment of ovarian diseases. However, their potential protective mechanisms are still unknown. Undoubtedly, a better understanding of the therapeutic molecular and cellular mechanisms of stem cells will address uncover strategies to increase their clinical application for multiple disorders such as POI. This paper describes a detailed account of the potential properties of different types of stem cells and provides a comprehensive review of their protective mechanisms, particularly MSC, in POI disorder. In addition, ongoing challenges and several strategies to improve the efficacy of MSC in clinical use are addressed. Therefore, this review will provide proof-of-concept for further clinical application of stem cells in POI.

Potential Druggability of Mesenchymal Stem/Stromal Cell-derived Exosomes

Exosomes secreted by mesenchymal stem/stromal cells (MSC-Exos) are advantageous candidate sources for novel acellular therapy. Despite the current standards of good manufacturing practice (GMP), the deficiency of suitable quality-control methods and the difficulties in large-scale preparation largely restrict the development of therapeutic products and their clinical applications worldwide. Herein, we mainly focus on three dominating issues commonly encountered in exosomal GMP, including issues upstream of the cell culture process, downstream of the purification process, exosomes quality control, and the drug properties of exosomes and their druggability from a corporate perspective. Collectively, in this review article, we put forward the issues of preparing clinical exosome drugs for the treatment of diverse diseases and provide new references for the clinical application of GMP-grade MSC-Exos.

A Review on Treatment of Premature Ovarian Insufficiency: Characteristics, Limitations, and Challenges of Stem Cell versus ExosomeTherapy

Premature ovarian insufficiency (POI) is a complex disorder that can result in varying degrees of infertility. Recently, mesenchymal stem cell (MSC) therapy and its derivatives, such as exosomes, have been introduced as novel strategies for the treatment of POI. This review discusses the features, limitations, and challenges of MSC and exosome therapy in the treatment of POI and provides readers with new insights for comparing and selecting chemical agents, optimizing doses, and other factors involved in study design and treatment strategies. MSC therapy has been shown to improve ovarian function in some animals with POI, but it can also have side effects such as high cost, time-consuming processes, limited lifespan and cell sources, loss of original characteristics during in vitro proliferation, dependence on specific culture environments, potential immune reactions, unknown therapeutic mechanisms, etc. However, exosome therapy is a newer therapy that has not been studied as extensively as MSC therapy, but that it has shown some promise in animal studies. The evidence for the effectiveness of MSC and exosome therapy is still limited, and more research is needed to determine whether these therapies are effective and safe for women with POI. This study presents a new perspective for researchers to advance their research in the fields of cell-based and cell-free therapies.