Leydig cell transplantation restores androgen production in surgically castrated prepubertal rats

Small Molecule Cocktails Promote Fibroblast-to-Leydig-like Cell Conversion for Hypogonadism Therapy

Male hypogonadism arises from the inadequate production of testosterone (T) by the testes, primarily due to Leydig cell (LC) dysfunction. Small molecules possess several advantages, including high cell permeability, ease of synthesis, standardization, and low effective concentration. Recent investigations have illuminated the potential of small molecule combinations to facilitate direct lineage reprogramming, removing the need for transgenes by modulating cellular signaling pathways and epigenetic modifications. In this study, we have identified a specific cocktail of small molecules, comprising forskolin, DAPT, purmorphamine, 8-Br-cAMP, 20α-hydroxycholesterol, and SAG, capable of promoting the conversion of fibroblasts into Leydig-like cells (LLCs). These LLCs expressed key genes involved in testosterone synthesis, such as Star, Cyp11a1, and Hsd3b1, and exhibited the ability to secrete testosterone in vitro. Furthermore, they successfully restored serum testosterone levels in testosterone-castrated mice in vivo. The small molecule cocktails also induced alterations in the epigenetic marks, specifically H3K4me3, and enhanced chromosomal accessibility on core steroidogenesis genes. This study presents a reliable methodology for generating Leydig-like seed cells that holds promise as a novel therapeutic approach for hypogonadism.

Epigenome editing based on CRISPR/dCas9p300 facilitates transdifferentiation of human fibroblasts into Leydig-like cells

Recently, Leydig cell (LCs) transplantation has a promising potential to treat male hypogonadism. However, the scarcity of seed cells is the actual barrier impeding the application of LCs transplantation. Utilizing the cutting-edge CRISPR/dCas9^VP64 technology, human foreskin fibroblasts (HFFs) were transdifferentiated into Leydig-like cells（iLCs） in previous study, but the efficiency of transdifferentiation is not very satisfactory. Therefore, this study was conducted to further optimize the CRISPR/dCas9 system for obtaining sufficient iLCs. First, the stable CYP11A1-Promoter-GFP-HFFs cell line was established by infecting HFFs with CYP11A1-Promoter-GFP lentiviral vectors, and then co-infected with dCas9^p300 and the combination of sgRNAs targeted to NR5A1, GATA4 and DMRT1. Next, this study adopted quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blot, and immunofluorescence to determine the efficiency of transdifferentiation, the generation of testosterone, the expression levels of steroidogenic biomarkers. Moreover, we utilized chromatin immuno-precipitation (ChIP) followed by quantitative polymerase chain reaction (ChIP-qPCR) to measure the levels of acetylation of targeted H3K27. The results revealed that advanced dCas9^p300 facilitated generation of iLCs. Moreover, the dCas9^p300-mediated iLCs significantly expressed the steroidogenic biomarkers and produced more testosterone with or without LH treatment than the dCas9^VP64-mediated. Additionally, preferred enrichment in H3K27ac at the promoters was detected only with dCas9^p300 treatment. The data provided here imply that the improved version of dCas9 can aid in the harvesting of iLCs, and will provide sufficient seed cells for cell transplantation treatment of androgen deficiency in the future.

Isolation of Primary Leydig Cells from Murine Testis

In males, Leydig cells are the primary source of testosterone, which is necessary for testis development, masculinization, and spermatogenesis. Leydig cells are a valuable cellular model for basic research; thus, it is important to develop an improved method for isolation and purification of Leydig cells from testes. The available methods for Leydig cell isolation have some drawbacks, including the need for sophisticated instruments, high cost, tediousness, and time consumption. Here, we describe an improved protocol for isolation of primary Leydig cells from testicular tissue by digestion with collagenase IV.

An autofluorescence-based isolation of Leydig cells for testosterone deficiency treatment

Effective procedures for the purification of Leydig cells (LCs) can facilitate functional studies and transplantation therapies. However, current methods to purify LCs from testes are still far from satisfactory. Here, we found that testicular autofluorescence existed in the interstitium along with the gradual maturation of LCs from birth to adulthood. These autofluorescent cells were further isolated by fluorescence-activated cell sorting (FACS) and determined to be composed of LCs and macrophages. To further purify LCs, we combined two fluorescence channels of FACS and successfully separated LCs and macrophages. Of note, we confirmed that the obtained LCs not only possessed high purity, viability and quantity but also had intact steroidogenic activity and excellent responsiveness to luteinizing hormone. Moreover, subcutaneous transplantation of isolated LCs could alleviate the symptoms of testosterone deficiency in castrated mice. In summary, we established an effective autofluorescence-based method for isolating LCs. This method will aid in the future success of using LCs for basic and translational applications.

Transplantation of encapsulated human Leydig-like cells: A novel option for the treatment of testosterone deficiency

Previous studies have demonstrated that the transplantation of alginate-poly-ʟ-lysine-alginate (APA)-encapsulated rat Leydig cells (LCs) provides a promising approach for treating testosterone deficiency (TD). Nevertheless, LCs have a limited capacity to proliferate, limiting the efficacy of LC transplantation therapy. Here, we established an efficient differentiation system to obtain functional Leydig-like cells (LLCs) from human stem Leydig cells (hSLCs). Then we injected APA-encapsulated LLCs into the abdominal cavities of castrated mice without an immunosuppressor. The APA-encapsulated cells survived and partially restored testosterone production for 90 days in vivo. More importantly, the transplantation of encapsulated LLCs ameliorated the symptoms of TD, such as fat accumulation, muscle atrophy and adipocyte accumulation in bone marrow. Overall, these results suggest that the transplantation of encapsulated LLCs is a promising new method for testosterone supplementation with potential clinical applications in TD.

Restorative functions of Autologous Stem Leydig Cell transplantation in a Testosterone-deficient non-human primate model

Rationale: Stem Leydig cells (SLCs) transplantation can restore testosterone production in rodent models and is thus a potential solution for treating testosterone deficiency (TD). However, it remains unknown whether these favorable effects will be reproduced in more clinically relevant large-animal models. Therefore, we assessed the feasibility, safety and efficacy of autologous SLCs transplantation in a testosterone-deficient non-human primate (NHP) model.

Methods: Cynomolgus monkey SLCs (CM-SLCs) were isolated from testis biopsies of elderly (> 19 years) cynomolgus monkeys by flow cytometry. Autologous CM-SLCs were injected into the testicular interstitium of 7 monkeys. Another 4 monkeys were injected the same way with cynomolgus monkey dermal fibroblasts (CM-DFs) as controls. The animals were then examined for sex hormones, semen, body composition, grip strength, and exercise activity.

Results: We first isolated CD271⁺ CM-SLCs which were confirmed to expand continuously and show potential to differentiate into testosterone-producing Leydig cells (LCs) in vitro. Compared with CM-DFs transplantation, engraftment of autologous CM-SLCs into elderly monkeys could significantly increase the serum testosterone level in a physiological pattern for 8 weeks, without any need for immunosuppression. Importantly, CM-SLCs transplantation recovered spermatogenesis and ameliorated TD-related symptoms, such as those related to body fat mass, lean mass, bone mineral density, strength and exercise capacity.

Conclusion: For the first time, our short-term observations demonstrated that autologous SLCs can increase testosterone levels and ameliorate relevant TD symptoms in primate models. A larger cohort with long-term follow-up will be required to assess the translational potential of autologous SLCs for TD therapy.

Leydig-like cells derived from reprogrammed human foreskin fibroblasts by CRISPR/dCas9 increase the level of serum testosterone in castrated male rats

In the past few years, Leydig cell (LC) transplantation has been regarded as an effective strategy for providing physiological patterns of testosterone in vivo. Recently, we have successfully converted human foreskin fibroblasts (HFFs) into functional Leydig‐like cells (iLCs) in vitro by using the CRISPR/dCas9 system, which shows promising potential for seed cells. However, it is not known whether the reprogrammed iLCs can survive or restore serum testosterone levels in vivo. Therefore, in this study, we evaluate whether reprogrammed iLCs can restore the serum testosterone levels of castrated rats when they are transplanted into the fibrous capsule. We first developed the castrated Sprague Dawley rat model through bilateral orchiectomy and subsequently injected extracellular matrix gel containing transplanted cells into the fibrous capsule of castrated rats. Finally, we evaluated dynamic serum levels of testosterone and luteinizing hormone (LH) in castrated rats, the survival of implanted iLCs, and the expression levels of Leydig steroidogenic enzymes by immunofluorescence staining and Western blotting. Our results demonstrated that implanted iLCs could partially restore the serum testosterone level of castrated rats, weakly mimic the role of adult Leydig cells in the hypothalamic‐pituitary‐gonadal axis for a short period, and survive and secrete testosterone, through 6 weeks after transplantation. Therefore, this study may be valuable for treating male hypogonadism in the future.

Differentiation of human umbilical cord mesenchymal stem cells into Leydig-like cells with defined molecular compounds

95% of the body's testosterone is produced by the Leydig Cells (LCs) in adult testis, and LC functional degradation can cause testosterone deficiency ultimately leading towards hypogonadism. The transplantation of LCs derived from stem cells is a very promising therapy to overcome the testosterone deficiency. The isolated umbilical cord mesenchymal stem cells (UMSCs) were identified by flow cytometry and adipogenic and osteogenic differentiation. Western blotting and reverse transcription polymerase chain reaction (RT-PCR) were used for the differentiated Leydig-like cell identification. The comparisons of the testosterone levels, gene expression levels, and cyclic adenosine monophosphate (cAMP) productions were performed through radioimmunoassay, quantitative polymerase chain reaction (qPCR), and cAMP assay kit, respectively. Here, it is stated that our isolated human UMSCs, which could positively express CD29, CD44, CD59, CD90, CD105, and CD166 but negatively express CD34 as well as could be differentiated into adipocytes and osteocytes, could be differentiated into Leydig-like cells (UMSC-LCs) using a novel differentiation method based on molecular compounds. The enrichment UMSC-LCs could secrete testosterone into the medium supernatant and produce considerable cAMP at the stimulation of luteinizing hormone (LH), and positively expressed LC lineage-typical markers LHCGR, SCARB1, SATR, CYP11A1, CYP17A1, HSD3B1, HSD17B3, and SF-1 as well as negatively expressed mesenchymal stem cell typical markers CD29, CD44, and CD105. The expression levels of NR3C4, PDGFRA, and NR3A1 in UMSC-LCs were higher than those of UMSCs and were comparable with LCs. These results illuminated that UMSCs could be differentiated into Leydig-like cells using the defined molecular compounds, which might further support MSC-derived Leydig cell transplantation therapy for testosterone insufficiency.

Differentiation of human adipose derived stem cells into Leydig-like cells with molecular compounds

Leydig cells (LCs) are the primary source of testosterone in the testis, and testosterone deficiency caused by LC functional degeneration can lead to male reproductive dysfunction. LC replacement transplantation is a very promising approach for this disease therapy. Here, we report that human adipose derived stem cells (ADSCs) can be differentiated into Leydig-like cells using a novel differentiation method based on molecular compounds. The isolated human ADSCs expressed positive CD29, CD44, CD59 and CD105, negative CD34, CD45 and HLA-DR using flow cytometry, and had the capacity of adipogenic and osteogenic differentiation. ADSCs derived Leydig-like cells (ADSC-LCs) acquired testosterone synthesis capabilities, and positively expressed LC lineage-specific markers LHCGR, STAR, SCARB1, SF-1, CYP11A1, CYP17A1, HSD3B1 and HSD17B3 as well as negatively expressed ADSC specific markers CD29, CD44, CD59 and CD105. When ADSC-LCs labelled with lipophilic red dye (PKH26) were injected into rat testes which were selectively eliminated endogenous LCs using ethylene dimethanesulfonate (EDS, 75 mg/kg), the transplanted ADSC-LCs could survive and function in the interstitium of testes, and accelerate the recovery of blood testosterone levels and testis weights. These results demonstrated that ADSCs could be differentiated into Leydig-like cells by few defined molecular compounds, which might lay the foundation for further clinical application of ADSC-LC transplantation therapy.

Cryopreservation of murine testicular Leydig cells by modified solid surface vitrification with supplementation of antioxidants

Reports on the vitrification of somatic cells are scarce. Here, we show that Leydig cells (murine cell line TM3) could be successfully vitrified by both open vitrification [plastic straw (PS) and plastic vials (PV)] and closed ultravitrification [microdrop (MD) and solid surface vitrification (SSV)], after protocol optimization. However, open ultravitrification resulted in better post-warming viability than closed systems of vitrification with highest success obtained in modified SSV (84.8 ± 1.86%; p < 0.05). Leydig cells vitrified-warmed by modified SSV also showed superior (p < 0.05) cell growth, mitochondrial activity and cytoplasmic esterase enzyme activity, than MD, PS and PV, respectively. It was also observed that vitrified-warmed cells had higher level of ROS activity than non-vitrified control cells (41.6 ± 4.0 vs. 16.7 ± 1.0; p < 0.05). Treatment of cells with glutathione (GSH) or 2-mercaptoethanol (2-ME) (0, 10, 50, 100 μM) significantly (p < 0.05) reduced the ROS activity but had no significant (p > 0.05) effect on post-warm viability. Nevertheless, antioxidant-treated cells had improved mitochondrial activity, cytoplasmic esterase activity and cell growth during in vitro culture (p < 0.05). In conclusion, our results suggest that modified SSV offers a viable method for vitrifying single cell suspension of Leydig cells. To the best of our knowledge, this is the first report on cryopreservation of Leydig cells by vitrification.

Mesenchymal stem cells from human umbilical cord ameliorate testicular dysfunction in a male rat hypogonadism model

Androgen deficiency is a physical disorder that not only affects adults but can also jeopardize children's health. Because there are many disadvantages to using traditional androgen replacement therapy, we have herein attempted to explore the use of human umbilical cord mesenchymal stem cells for the treatment of androgen deficiency. We transplanted CM-Dil-labeled human umbilical cord mesenchymal stem cells into the testes of an ethane dimethanesulfonate (EDS)-induced male rat hypogonadism model. Twenty-one days after transplantation, we found that blood testosterone levels in the therapy group were higher than that of the control group (P = 0.037), and using immunohistochemistry and flow cytometry, we observed that some of the CM-Dil-labeled cells expressed Leydig cell markers for cytochrome P450, family 11, subfamily A, polypeptide 1, and 3-β-hydroxysteroid dehydrogenase. We then recovered these cells and observed that they were still able to proliferate in vitro. The present study shows that mesenchymal stem cells from human umbilical cord may constitute a promising therapeutic modality for the treatment of male hypogonadism patients.

Differentiation of human umbilical cord mesenchymal stem cells into steroidogenic cells in vitro

Although previous studies have shown that stem cells can be differentiated into Leydig cells by gene transfection, a simple, safe and effective induction method has not yet been reported. Therefore, the present study investigated novel methods for the induction of human umbilical cord mesenchymal stem cell (HUMSC) differentiation into Leydig-like, steroidogenic cells. HUMSCs were acquired using the tissue block culture attachment method, and the expression of MSC surface markers was evaluated by flow cytometry. Leydig cells were obtained by enzymatic digestion and identified by lineage-specific markers via immunofluorescence. Third-passage HUMSCs were cultured with differentiation-inducing medium (DIM) or Leydig cell-conditioned medium (LC-CM), and HUMSCs before induction were used as the control group. Following the induction of HUMSCs, Leydig cell lineage-specific markers (CYP11A1, CYP17A1 and 3β-HSD) were positively identified using immunofluorescence analysis. Additionally, reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to evaluate the expression levels of these genes and enzymes. In contrast, the control group cells did not show the characteristics of Leydig cells. Collectively, these results indicate that, under in vitro conditions, LC-CM can achieve a comparable effect to that of DIM on inducing HUMSCs differentiation into steroidogenic cells.

Changes in Sexual Behavior of Orchidectomized Rats Under Influence of Allotransplantation of Testicular Interstitial Cell Suspension

Transplantation of hormone-producing cells is an experimental endocrine dysfunction treatment. The present study investigated the effects of orchidectomy (OE) and transplantation of interstitial cell suspension (ICS) on rat sexual behavior. Adult experimental animals were divided into two populations. One of these populations had sexual experience before the experiment and the other did not. Each population was divided into three groups: control group and two orchidectomized groups. One of the orchidectomized groups was treated with ICS, and the other was treated with the vehicle. The changes in the sexual behavior were investigated on the following parameters: mount latency (ML), intromission latency (IL), ejaculation latency (EL), mount frequency (MF), intromission frequency (IF), copulatory efficacy (CE), and IF/EL ratio. The investigation of these changes lasted 4 weeks after ICS transplantation. The parameters of sexual behavior reflected a decrease in sexual function after OE at the beginning of the observation, especially for the animals that did not have a sexual experience. However, it was shown that sexual activity increased in the following 4 weeks. We have indicated that the loss of gonads attenuated the capacity to acquire sexual experience; nonetheless, it did not mean that the animals completely lost this capacity. Transplantation of ICS facilitated the maintenance of male sexual behavior after OE, fractionally enlarged the size of regressed seminal vesicles of the animals, and increased the free testosterone (T) level. These findings suggest the ICS can be considered as a temporal source of androgens, which can facilitate a restoration of sexual activity.

Quinestrol induces spermatogenic apoptosis in vivo via increasing pro-apoptotic proteins in adult male mice

The effects of quinestrol on spermatogenesis were investigated in adult male mice by daily intragastric administration of quinestrol with various doses of 5, 10, 50 and 100mg/kg body weight for 10 days. The sperm counts declined while the number of abnormal spermatozoa went up in mice treated with quinestrol. The testicular weight and seminiferous tubular area gradually declined with increasing dosages of quinestrol to 50 and 100mg/kg. Rarefied germ cells showed irregular distributions in the seminiferous tubules of mice treated with 50 and 100mg/kg quinestrol. Apoptosis was highly pronounced in spermatogonia, spermatocytes, spermatids and Leydig cells. Antioxidant enzyme activities - superoxide dismutase and glutathione peroxidase - as well as total antioxidant capacity significantly reduced, while malondialdehyde contents increased. The number of germ cells expressing caspase-3, p53, Bax and FasL significantly increased whereas cells expressing Bcl-2 significantly decreased in groups treated with 50 and 100mg/kg quinestrol compared with the control. The concentration of nitrogen monoxidum also increased significantly under these dosages. The results suggest that quinestrol stimulates oxidative stress to induce apoptosis in spermatogenic cells through the mitochondrial and death receptor pathways in adult male mice.