Single xenotransplant of rat brown adipose tissue prolonged the ovarian lifespan of aging mice by improving follicle survival

The effect of adipose-derived mesenchymal stem cell transplantation on ovarian mitochondrial dysfunction in letrozole-induced polycystic ovary syndrome in rats: the role of PI3K-AKT signaling pathway

OBJECTIVE

The present study aimed to elucidate how mesenchymal stem cells (MSCs) application could efficiently attenuate pathological changes of letrozole-induced poly cystic ovary syndrome (PCOS) by modulating mitochondrial dynamic via PI3K-AKT pathway.

METHODS

Thirty-two female rats were randomly divided into four experimental groups: Sham, PCOS, PCOS + MSCs, and PCOS + MSCs + LY294002. The Sham group received 0.5% w/v carboxymethyl cellulose (CMC); the PCOS group received letrozole (1 mg/kg, daily) in 0.5% CMC for 21 days. Animals in the PCOS + MSCs group received 1 × 106 MSCs/rat (i.p,) on the 22th day of the study. In the PCOS + MSCs + LY294002 group, rats received LY294002 (PI3K-AKT inhibitor) 40 min before MSC transplantation. Mitochondrial dynamic gene expression, mitochondrial membrane potential (MMP), citrate synthase (CS) activity, oxidative stress, inflammation, ovarian histological parameters, serum hormone levels, homeostatic model assessment for insulin resistance (HOMA-IR), insulin and glucose concentrations, p-PI3K and p-AKT protein levels were evaluated at the end of the experiment.

RESULTS

PCOS rats showed a significant disruption of mitochondrial dynamics and histological changes, lower MMP, CS, ovary super oxide dismutase (SOD) and estrogen level. They also had a notable rise in insulin and glucose concentrations, HOMA-IR, testosterone level, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels, ovarian malondialdehyde (MDA) content as well as a notable decrease in p-PI3K and p-AKT protein levels compared to the Sham group. In the PCOS + MSCs group, the transplantation of MSCs could improve the above parameters. Administration of LY294002 (PI3K-AKT pathway inhibitor) deteriorated mitochondrial dynamic markers, oxidative stress status, inflammation markers, hormonal levels, glucose, and insulin levels and follicular development compared to the PCOS + MSCs group.

CONCLUSIONS

This study demonstrated that the protective effects of MSC transplantation in regulating mitochondrial dynamics, promoting mitochondrial biogenesis, competing with redox status and inflammation response were mainly mediated through the PI3K-AKT pathway in the PCOS model.

An update on the secretory functions of brown, white, and beige adipose tissue: Towards therapeutic applications

Adipose tissue, including white adipose tissue (WAT), brown adipose tissue (BAT), and beige adipose tissue, is vital in modulating whole-body energy metabolism. While WAT primarily stores energy, BAT dissipates energy as heat for thermoregulation. Beige adipose tissue is a hybrid form of adipose tissue that shares characteristics with WAT and BAT. Dysregulation of adipose tissue metabolism is linked to various disorders, including obesity, type 2 diabetes, cardiovascular diseases, cancer, and infertility. Both brown and beige adipocytes secrete multiple molecules, such as batokines, packaged in extracellular vesicles or as soluble signaling molecules that play autocrine, paracrine, and endocrine roles. A greater understanding of the adipocyte secretome is essential for identifying novel molecular targets in treating metabolic disorders. Additionally, microRNAs show crucial roles in regulating adipose tissue differentiation and function, highlighting their potential as biomarkers for metabolic disorders. The browning of WAT has emerged as a promising therapeutic approach in treating obesity and associated metabolic disorders. Many browning agents have been identified, and nanotechnology-based drug delivery systems have been developed to enhance their efficacy. This review scrutinizes the characteristics of and differences between white, brown, and beige adipose tissues, the molecular mechanisms involved in the development of the adipocytes, the significant roles of batokines, and regulatory microRNAs active in different adipose tissues. Finally, the potential of WAT browning in treating obesity and atherosclerosis, the relationship of BAT with cancer and fertility disorders, and the crosstalk between adipose tissue with circadian system and circadian disorders are also investigated.

Multiple treatments with human embryonic stem cell-derived mesenchymal progenitor cells preserved the fertility and ovarian function of perimenopausal mice undergoing natural aging

OBJECTIVES

Currently, no approved stem cell-based therapies for preserving ovarian function during aging. To solve this problem, we developed a long-term treatment for human embryonic stem cell-derived mesenchymal progenitor cells (hESC-MPCs). We investigated whether the cells retained their ability to resist ovarian aging, which leads to delayed reproductive senescence.

MATERIALS AND METHODS

In a middle-aged female model undergoing natural aging, we analyzed whether hESC-MPCs benefit the long-term maintenance of reproductive fecundity and ovarian reservoirs and how their transplantation regulates ovarian function.

RESULTS

The number of primordial follicles and mice with regular estrous cycles were increased in perimenopausal mice who underwent multiple introductions of hESC-MPCs compared to age-matched controls. The estradiol levels in the hESC-MPCs group were restored to those in the young and adult groups. Embryonic development and live birth rates were higher in the hESC-MPC group than in the control group, suggesting that hESC-MPCs delayed ovarian senescence. In addition to their direct effects on the ovary, multiple-treatments with hESC-MPCs reduced ovarian fibrosis by downregulating inflammation and fibrosis-related genes via the suppression of myeloid-derived suppressor cells (MDSCs) produced in the bone marrow.

CONCLUSIONS

Multiple introductions of hESC-MPCs could be a useful approach to prevent female reproductive senescence and that these cells are promising sources for cell therapy to postpone the ovarian aging and retain fecundity in perimenopausal women.

miR-143-3p Promotes Ovarian Granulosa Cell Senescence and Inhibits Estradiol Synthesis by Targeting UBE2E3 and LHCGR

The ovary is a highly susceptible organ to senescence, and granulosa cells (GCs) have a crucial role in oocyte development promotion and overall ovarian function maintenance. As age advances, GCs apoptosis and dysfunction escalate, leading to ovarian aging. However, the molecular mechanisms underpinning ovarian aging remain poorly understood. In this study, we observed a correlation between the age-related decline of fertility and elevated expression levels of miR-143-3p in female mice. Moreover, miR-143-3p was highly expressed in senescent ovarian GCs. The overexpression of miR-143-3p in GCs not only hindered their proliferation and induced senescence-associated secretory phenotype (SASP) but also impeded steroid hormone synthesis by targeting ubiquitin-conjugating enzyme E2 E3 (Ube2e3) and luteinizing hormone and human chorionic gonadotropin receptor (Lhcgr). These findings suggest that miR-143-3p plays a substantial role in senescence and steroid hormone synthesis in GCs, indicating its potential as a therapeutic target for interventions in the ovarian aging process.

Brown adipose tissue-derived exosomes delay fertility decline in aging mice

Introduction

Ovarian aging has steadily grown to be a significant health issue for women as a result of the increase in average life expectancy and the postponement of reproductive age. One of the important pathological foundations of ovarian aging is formed by mitochondrial dysfunction, which causes decreases in follicle quantity and oocyte quality. In recent years, brown adipose tissue (BAT) transplantation has been proven as an effective treatment for aging-related diseases, such as ovarian aging. However, BAT transplantation is an invasive operation with long-term risks. Therefore, we need to find an alternative strategy.

Methods

We injected BAT-derived exosomes into eight-month-old C57BL/6 female mice. The fertility was detected by the estrous cycle and mating test. The changes of ovary and oocyte were measured by ovarian volume, organ coefficient, follicle counting, and oocyte maturation rate. ROS level, mitochondrial membrane potential and ATP level were measured to analyze the mitochondrial function of oocytes. The changes in metabolism were explored by cold stimulation test, body weight and blood sugar. The possible molecular mechanism was further investigated by RNA sequencing.

Results

In terms of fertility, the estrous cycle of aging mice after BAT-derived exosome intervention was more regular, and the number of progenies and litters was increased. At the tissue level, the ovaries in the BAT-exosome group were larger, and the number of primordial follicles, secondary follicles, antral follicles and total follicles increased. At the cellular level, BAT-derived exosomes improved the maturation of oocytes in vivo and in vitro, increased the mitochondrial membrane potential and ATP levels of oocytes, and decreased ROS levels. Besides, BAT-derived exosomes ameliorated the metabolism and viability of aging mice. Furthermore, mRNA sequencing showed that BAT exosomes altered the expression levels of genes related to metabolism and the quality of oocytes.

Conclusion

BAT-derived exosomes enhanced mitochondrial function, promoted follicle survival, improved fertility, and extended ovarian lifespan in aging mice.

Brown Adipose Tissue Transplantation

The metabolic benefits of brown adipose tissue (BAT) are well known. Increasing the BAT content and/or activity is a proposed therapeutic approach to combat metabolic disease. Activation and induction of endogenous BAT have achieved varying degrees of success in correcting obesity, insulin resistance, and cardiovascular disease, with some limitations. Transplantation of BAT from healthy donors is another approach proven safe and effective in rodent models. In diet-induced models of obesity and insulin resistance, BAT transplants prevent obesity, increase insulin sensitivity, and improve glucose homeostasis and whole-body energy metabolism. In mouse models of insulin-dependent diabetes, subcutaneous transplantation of healthy BAT produces long-term euglycemia without the need for insulin or immunosuppression. Considering the immunomodulatory and anti-inflammatory properties of healthy BAT, transplantation may be a more effective approach to combat metabolic disease in the long term. Here we describe in detail the technique for subcutaneous BAT transplantation.

Mesenchymal stem cells combined with autocrosslinked hyaluronic acid improve mouse ovarian function by activating the PI3K-AKT pathway in a paracrine manner

Background

Declining ovarian function in advance-aged women and in premature ovarian insufficiency (POI) patients seriously affects quality of life, and there is currently no effective treatment to rescue ovarian function in clinic. Stem cell transplantation is a promising therapeutic strategy for ovarian aging, but its clinical application is limited due to the low efficiency and unclear mechanism. Here, a novel combination of umbilical cord-mesenchymal stem cells (UC-MSCs) and autocrosslinked hyaluronic acid (HA) gel is explored to rescue ovarian reserve and fecundity in POI and naturally aging mice.

Methods

To investigate HA prolonged the survival after UC-MSCs transplantation, PCR and immunofluorescence were performed to track the cells on day 1, 3, 7 and 14 after transplantation. The effects of HA on UC-MSCs were analyzed by CCK8 assay, RNA-sequencing and 440 cytokine array. In vivo experiments were conducted to evaluate the therapeutic effects of UC-MSCs combined with HA transplantation in 4-vinylcyclohexene diepoxide (VCD)-induced POI mice and naturally aging mice model. Ovarian function was analyzed by ovarian morphology, follicle counts, estrous cycle, hormone levels and fertility ability. To investigate the mechanisms of stem cell therapy, conditioned medium was collected from UC-MSCs and fibroblast. Both in vitro ovarian culture model and 440 cytokine array were applied to assess the paracrine effect and determine the underlying mechanism. Hepatocyte growth factor (HGF) was identified as an effective factor and verified by HGF cytokine/neutralization antibody supplementation into ovarian culture system.

Results

HA not only prolongs the retention of UC-MSCs in the ovary, but also boosts their secretory function, and UC-MSCs promote follicular survival by activating the PI3K-AKT pathway through a paracrine mechanism both in vitro and in vivo. More importantly, HGF is identified as the key functional cytokine secreted by MSCs.

Conclusions

The results show that HA is an excellent cell scaffold to improve the treatment efficiency of UC-MSCs for ovarian aging under both physiological and pathological conditions, and the therapeutic mechanism is through activation of the PI3K-AKT pathway via HGF. These findings will facilitate the clinical application of MSCs transplantation for ovarian disorders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02724-3.

Effects of Hochuekkito, a traditional Japanese medicine (Kampo), on reproduction of aging female mice

Purpose

To determine the potentials of Hochuekkito (HET) treatment for aging infertility.

Methods

Mice at 36 weeks of age were fed without (control, n = 40) or with low (100 mg/kg/day, n = 24) and high (1000 mg/kg/day, n = 38) doses of HET for 12 weeks. Aging animals at 48 weeks of age were used for in vitro fertilization-embryo transfer (IVF-ET), and their ovaries were subjected to histological and quantitative inflammation analyses.

Results

HET administration decreased transcript levels of ovarian inflammatory markers, interleukin 6 (IL-6), IL-1β, tumor necrosis factor (TNF)-α, and interferon-gamma (IFN-γ) but suppressed ovulation rates and the number of ovulated oocytes in aging mice. Furthermore, HET treatment decreased the rates of oocytes maturation and fertilization and the cumulus-cell expression of TNF-α-induced protein 6 and epidermal growth factor receptor. After IVF-ET, no improvement of declined live offspring rate by aging was achieved by HET administration, although there were no adverse effects on embryo development and implantation as well as gross morphology and bodyweight of pups.

Conclusion

Present study indicated HET treatment interfered with ovulation and fertilization in aging mice without affecting ovarian follicle development. No improvement on the age-associated decline of live offspring rate and follicle development was achieved after HET treatment.

Inhibiting bridge integrator 2 phosphorylation leads to improved oocyte quality, ovarian health and fertility in aging and after chemotherapy in mice

Female ovaries degenerate about 20 years earlier than testes leading to reduced primordial follicle reserve and a reduction in oocyte quality. Here we found that bridge integrator 2 (BIN2) is enriched in mouse ovaries and oocytes and that global knockout of this protein improves both female fertility and oocyte quality. Quantitative ovarian proteomics and phosphoproteomics showed that Bin2 knockout led to a decrease in phosphorylated ribosomal protein S6 (p-RPS6), a component of the mammalian target of rapamycin pathway and greatly increased nicotinamide nucleotide transhydrogenase (NNT), the free-radical detoxifier. Mechanistically, we find that phosphorylation of BIN2 at Thr423 and Ser424 leads to its translocation from the membrane to the cytoplasm, subsequent phosphorylation of RPS6 and inhibition of Nnt translation. We synthesized a BIN2-penetrating peptide (BPP) designed to inhibit BIN2 phosphorylation and found that a 3-week BPP treatment improved primordial follicle reserve and oocyte quality in aging and after chemotherapy-induced premature ovarian failure without discernible side effects.

Autologous transplantation of thecal stem cells restores ovarian function in nonhuman primates

Premature ovarian insufficiency (POI) is defined as the loss of ovarian activity under the age of 40. Theca cells (TCs) play a vital role during folliculogenesis and TCs dysfunction participate in the pathogenesis of POI. Therefore, transplantation of thecal stem cells (TSCs), which are capable of self-renewal and differentiation into mature TCs, may provide a new strategy for treating POI. To investigate the feasibility, safety, and efficacy of TSCs transplantation in clinically relevant non-human primate (NHP) models, we isolate TSCs from cynomolgus monkeys, and these cells are confirmed to expand continuously and show potential to differentiate into mature TCs. In addition, engraftment of autologous TSCs into POI monkeys significantly improves hormone levels, rescues the follicle development, promotes the quality of oocytes and boosts oocyte maturation/fertilization rate. Taken together, these results for the first time suggest that autologous TSCs can ameliorate POI symptoms in primate models and shed new light on developing stem cell therapy for POI.

Sex differences and aging: Is there a role of brown adipose tissue?

In every population across the world, women live significantly longer than men; however, the underlying physiological processes that drive these sex differences in age-specific mortality are largely unknown. Recently, the role of adipose tissue in aging and longevity has been a focus of biomedical research in both humans and rodent models. Specifically, brown adipose tissue, a thermoregulatory tissue originally thought to not exist past infancy in humans, has been shown to potentially play a role in health throughout the lifespan. Females have larger adult brown adipose depots that are not just larger in size but also more efficient in non-shivering thermogenesis. This improved functioning of the brown adipose tissue may potentially lead to improved female health, and we hypothesize that this advantage may be of even bigger significance in the older population. Here, we briefly review what is known about sex differences in aging and how sex differences in brown adipose tissue may be contributing to the female lifespan advantage. These questions have usually been addressed in large experimental studies in rodents as a translational model of human aging. Overall, we propose that a better understanding of the thermogenesis-metabolism nexus is necessary in biomedical research, and sex differences in these factors may contribute to the female longevity bias seen in human populations.

Brown Adipose Transplantation Improves Polycystic Ovary Syndrome-Involved Metabolome Remodeling

Polycystic ovary syndrome (PCOS) is a complex reproductive, endocrine, and metabolic disorder in reproductive-age women. In order to explore the active metabolites of brown adipose tissue (BAT) transplantation in improving the reproductive and metabolic phenotypes in a PCOS rat model, the metabolites in the recipient's BAT were explored using the liquid chromatography-mass spectrometry technique. In total, 9 upregulated and 13 downregulated metabolites were identified. They were roughly categorized into 12 distinct classes, mainly including glycerophosphoinositols, glycerophosphocholines, and sphingolipids. Ingenuity pathway analysis predicted that these differentially metabolites mainly target the PI3K/AKT, MAPK, and Wnt signaling pathways, which are closely associated with PCOS. Furthermore, one of these differential metabolites, sphingosine belonging to sphingolipids, was randomly selected for further experiments on a human granulosa-like tumor cell line (KGN). It significantly accelerated the apoptosis of KGN cells induced by dihydrotestosterone. Based on these findings, we speculated that metabolome changes are an important process for BAT transplantation in improving PCOS. It might be a novel therapeutic target for PCOS treatment.

Single xenotransplant of rat brown adipose tissue prolonged the ovarian lifespan of aging mice by improving follicle survival

Prolonging the ovarian lifespan is attractive and challenging. An optimal clinical strategy must be safe, long-acting, simple, and economical. Allotransplantation of brown adipose tissue (BAT), which is most abundant and robust in infants, has been utilized to treat various mouse models of human disease. Could we use BAT to prolong the ovarian lifespan of aging mice? Could we try BAT xenotransplantation to alleviate the clinical need for allogeneic BAT due to the lack of voluntary infant donors? In the current study, we found that a single rat-to-mouse (RTM) BAT xenotransplantation did not cause systemic immune rejection but did significantly increase the fertility of mice and was effective for more than 5 months (equivalent to 10 years in humans). Next, we did a series of analysis including follicle counting; AMH level; estrous cycle; mTOR activity; GDF9, BMP15, LHR, Sirt1, and Cyp19a level; ROS and annexin V level; IL6 and adiponectin level; biochemical blood indices; body temperature; transcriptome; and DNA methylation studies. From these, we proposed that rat BAT xenotransplantation rescued multiple indices indicative of follicle and oocyte quality; rat BAT also improved the metabolism and general health of the aging mice; and transcriptional and epigenetic (DNA methylation) improvement in F0 mice could benefit F1 mice; and multiple KEGG pathways and GO classified biological processes the differentially expressed genes (DEGs) or differentially methylated regions (DMRs) involved were identical between F0 and F1. This study could be a helpful reference for clinical BAT xenotransplantation from close human relatives to the woman.