Isolation of human testicular cells and co-culture with embryonic stem cells

Maslinic acid supplementation prevents di(2-ethylhexyl) phthalate-induced apoptosis via PRDX6 in peritubular myoid cells of Chinese forest musk deer

Chinese forest musk deer (FMD), an endangered species, have exhibited low reproductive rates even in captivity due to stress conditions. Investigation revealed the presence of di(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, in the serum and skin of captive FMDs. Feeding FMDs with maslinic acid (MA) has been observed to alleviate the stress response and improve reproductive rates, although the precise molecular mechanisms remain unclear. Therefore, this study aims to investigate the molecular mechanisms underlying the alleviation of DEHP-induced oxidative stress and cell apoptosis in primary peritubular myoid cells (PMCs) through MA intake. Primary PMCs were isolated and exposed to DEHP in vitro. The results demonstrated that DEHP significantly suppressed antioxidant levels and promoted cell apoptosis in primary PMCs. Moreover, interfering with the expression of PRDX6 was found to induce excessive reactive oxygen species (ROS) production and cell apoptosis in primary PMCs. Supplementation with MA significantly upregulated the expression of PRDX6, thereby attenuating DEHP-induced oxidative stress and cell apoptosis in primary PMCs. These findings provide a theoretical foundation for mitigating stress levels and enhancing reproductive capacity of in captive FMDs.

Engineering of gelatin scaffold by extracellular matrix of Sertoli cells for embryonic stem cell proliferation

Mimicking the microenvironment of seminiferous tubules plays an indispensable role in directing differentiation of stem cells toward germ cells in vitro. In this work, we fabricated electrospun gelatin (EG) mats (i.e., with diameter <500 nm) conditioned with Sertoli cells' extracellular matrix (ECM) to simulate both 3D structures and composition of normal testis tissue. Sertoli cells were isolated from mice testis and represented through immunocytochemistry (ICC) staining for expression of vimentin, a specific marker of Sertoli cells. The morphological characteristics of ECM-coated scaffold were investigated under scanning electron microscope (SEM). The efficient elimination of cells was confirmed by MTT assay. Furthermore, the cyto/biocompatibility of ECM-conditioned EG scaffold was determined for Sertoli cells and embryonic stem cells (ESCs), alone and as in co-culture. According to the results, the designed scaffold provided a mat for cell proliferation with negligible toxicity (almost 100% cell viability). SEM micrographs displayed cells with elongated shape and complete stretching morphology when compared with those cultured on scaffold without ECM. Moreover, an enhanced differentiation of ESCs toward sperm-generating cells was obtained through co-culturing of Sertoli cells and ESCs, where cell viability was found almost 100%. Our findings introduce the ECM-conditioned EG scaffold as a potentially influential engineered substrate for in vitro guidance of stem cells differentiation by mimicking the native microenvironment.

Bovine adipose tissue-derived mesenchymal stem cells self-assemble with testicular cells and integrates and modifies the structure of a testicular organoids

Mesenchymal stem cells (MSC) display self-renewal and mesodermal differentiation potentials. These characteristics make them potentially useful for in vitro derivation of gametes, which may constitute experimental therapies for human and animal reproduction. Organoids provide a spatial support and may simulate a cellular niche for in vitro studies. In this study, we aimed at evaluating the potential integration of fetal bovine MSCs derived from adipose tissue (AT-MSCs) in testicular organoids (TOs), their spatial distribution with testicular cells during TO formation and their potential for germ cell differentiation. TOs were developed using Leydig, Sertoli, and peritubular myoid cells that were previously isolated from bovine testes (n = 6). Thereafter, TOs were characterized using immunofluorescence and Q-PCR to detect testicular cell-specific markers. AT-MSCs were labeled with PKH26 and then cultured with testicular cells at a concentration of 1 × 106 cells per well in Ultra Low Attachment U-shape bottom (ULA) plates. TOs formed by testicular cells and AT-MSCs (TOs + AT-MSCs) maintained a rounded structure throughout the 28-day culture period and did not show significant differences in their diameters. Conversely, control TOs exhibited a compact structure until day 7 of culture, while on day 28 they displayed cellular extensions around their structure. Control TOs had greater (P < 0.05) diameters compared to TOs + AT-MSCs. AT-MSCs induced an increase in proportion of Leydig and peritubular myoid cells in TOs + AT-MSCs; however, did not induce changes in the overall gene expression of testicular cell-specific markers. STAR immunolabelling detected Leydig cells that migrated from the central area to the periphery and formed brunches in control TOs. However, in TOs + AT-MSCs, Leydig cells formed a compact peripheral layer. Sertoli cells immunodetected using WT1 marker were observed within the central area forming clusters of cells in TOs + AT-MSCs. The expression of COL1A associated to peritubular myoids cells was restricted to the central region in TOs + AT-MSCs. Thus, during a 28-day culture period, fetal bovine AT-MSCs integrated and modified the structure of the TOs, by restricting formation of branches, limiting the overall increase in diameters and increasing the proportions of Leydig and peritubular myoid cells. AT-MSCs also induced a reorganization of testicular cells, changing their distribution and particularly the location of Leydig cells.

Induction of apoptosis by cannabidiol and its main metabolites in human Leydig cells

Cannabidiol (CBD) is one of the most prevalent and abundant cannabinoids extracted from the plant Cannabis sativa. CBD has been reported to induce male reproductive toxicity in animal models. In this study, we examined the effects of CBD and its main metabolites, 7-carboxy-CBD and 7-hydroxy-CBD, on primary human Leydig cells, which play a crucial role in male reproductive health. Our results showed that CBD, at concentrations below the Bayesian benchmark dose (BMD)50, inhibited the growth of human Leydig cells by arresting the cell cycle at G1/S transition, disrupting cell cycle regulators, and decreasing DNA synthesis. Concentration-response transcriptomic profiling identified that apoptosis was one of the top biological processes significantly affected by treatment with CBD for 24 h. The occurrence of apoptosis was confirmed by increased activation of caspase-3/7 and an increased proportion of annexin V and propidium iodide (PI)-positive cells. Similar to CBD, both 7-carboxy-CBD and 7-hydroxy-CBD decreased cell viability and induced apoptosis after treatment for 24 h. 7-Hydroxy-CBD and 7-carboxy-CBD showed lower cytotoxicity than CBD, and 7-carboxy-CBD had the lowest cytotoxicity among the three compounds. Our findings revealed that CBD and its main metabolites can cause adverse effects on primary human Leydig cells.

In Vitro and In Vivo Models for Drug Transport Across the Blood-Testis Barrier

The blood-testis barrier (BTB) is a selectively permeable membrane barrier formed by adjacent Sertoli cells (SCs) in the seminiferous tubules of the testes that develops intercellular junctional complexes to protect developing germ cells from external pressures. However, due to this inherent defense mechanism, the seminiferous tubule lumen can act as a pharmacological sanctuary site for latent viruses (e.g., Ebola, Zika) and cancers (e.g., leukemia). Therefore, it is critical to identify and evaluate BTB carrier-mediated drug delivery pathways to successfully treat these viruses and cancers. Many drugs are unable to effectively cross cell membranes without assistance from carrier proteins like transporters because they are large, polar, and often carry a charge at physiologic pH. SCs express transporters that selectively permit endogenous compounds, such as carnitine or nucleosides, across the BTB to support normal physiologic activity, although reproductive toxicants can also use these pathways, thereby circumventing the BTB. Certain xenobiotics, including select cancer therapeutics, antivirals, contraceptives, and environmental toxicants, are known to accumulate within the male genital tract and cause testicular toxicity; however, the transport pathways by which these compounds circumvent the BTB are largely unknown. Consequently, there is a need to identify the clinically relevant BTB transport pathways in in vitro and in vivo BTB models that recapitulate human pharmacokinetics and pharmacodynamics for these xenobiotics. This review summarizes the various in vitro and in vivo models of the BTB reported in the literature and highlights the strengths and weaknesses of certain models for drug disposition studies. SIGNIFICANCE STATEMENT: Drug disposition to the testes is influenced by the physical, physiological, and immunological components of the blood-testis barrier (BTB). But many compounds are known to cross the BTB by transporters, resulting in pharmacological and/or toxicological effects in the testes. Therefore, models that assess drug transport across the human BTB must adequately account for these confounding factors. This review identifies and discusses the benefits and limitations of various in vitro and in vivo BTB models for preclinical drug disposition studies.

Low-Intensity Pulsed Ultrasound Alleviates Human Testicular Leydig Cell Senescence In Vitro

Aging has a significant negative impact on human testicular function; steroidogenesis is gradually impaired, and testosterone replacement therapy still has many risks. Low-intensity pulsed ultrasound (LIPUS) has been used as a novel non-invasive treatment for male erectile dysfunction and other fields, and has been shown to increase testosterone levels in animal models. Testosterone is synthesized and secreted by Leydig cells (LCs), and the serum testosterone level decreases after aging due to the LCs senescence. However, the effect of LIPUS on human senescent LCs has not been reported. In this study, human senescent LCs were isolated and stimulated with different energy intensities in vitro, and cell morphology, cell apoptosis, cell proliferation, cell senescence levels, lipid droplet number, testosterone and INSL3 secretion levels were tested and analyzed. Quantitative Polymerase Chain Reaction (QPCR) and Western Blot were performed to compare cell senescence characteristics and the expression profile of key pathways of testosterone secretion, and transcriptome analysis was performed to explore the signaling pathways of LCs alteration after LIPUS stimulation. It was safe and effective to stimulate LCs with the 75 mW/cm² energy of LIPUS in vitro, which not only improved the senescence phenotype, but also effectively enhanced the secretory function of LCs in vitro, and increased the expression of key pathways of the testosterone synthesis pathway. These results suggest that LIPUS could be used as a novel treatment to human senescent LCs with decreased testosterone secretion levels in vitro.

Generation and Characterization of Bovine Testicular Organoids Derived from Primary Somatic Cell Populations

Organoids are 3D-culture systems composed of tissue-specific primary cells that self-organize and self-renew, creating structures similar to those of their tissue of origin. Testicular organoids (TOs) may recreate conditions of the testicular niche in domestic and wild cattle; however, no previous TO studies have been reported in the bovine species. Thus, in the present study, we sought to generate and characterize bovine TOs derived from primary testicular cell populations including Leydig, Sertoli and peritubular myoid cells. Testicular cells were isolated from bovine testes and cultured in ultra-low attachment (ULA) plates and Matrigel. TOs were cultured in media supplemented from day 3 with 100 ng/mL of BMP4 and 10 ng/mL of FGF2 and from day 7 with 15 ng/mL of GDNF. Testicular cells were able to generate TOs after 3 days of culture. The cells positive for STAR (Leydig) and COL1A (peritubular myoid) decreased (p < 0.05), whereas cells positive for WT1 (Sertoli) increased (p < 0.05) in TOs during a 28-day culture period. The levels of testosterone in media increased (p < 0.05) at day 28 of culture. Thus, testicular cells isolated from bovine testes were able to generate TOs under in vitro conditions. These bovine TOs have steroidogenic activity characterized by the production of testosterone.

Roles of Spermatogonial Stem Cells in Spermatogenesis and Fertility Restoration

Spermatogonial stem cells (SSCs) are a group of adult stem cells in the testis that serve as the foundation of continuous spermatogenesis and male fertility. SSCs are capable of self-renewal to maintain the stability of the stem cell pool and differentiation to produce mature spermatozoa. Dysfunction of SSCs leads to male infertility. Therefore, dissection of the regulatory network of SSCs is of great significance in understanding the fundamental molecular mechanisms of spermatogonial stem cell function in spermatogenesis and the pathogenesis of male infertility. Furthermore, a better understanding of SSC biology will allow us to culture and differentiate SSCs in vitro, which may provide novel stem cell-based therapy for assisted reproduction. This review summarizes the latest research progress on the regulation of SSCs, and the potential application of SSCs for fertility restoration through in vivo and in vitro spermatogenesis. We anticipate that the knowledge gained will advance the application of SSCs to improve male fertility. Furthermore, in vitro spermatogenesis from SSCs sets the stage for the production of SSCs from induced pluripotent stem cells (iPSCs) and subsequent spermatogenesis.

A new frontier in therapy personalisation based on in vitro studies to preserve fertility potential of men

At present, there is still a lack of attention to male infertility and fertility impairment. Indeed, the pathologies affecting the reproductive area in man are derived from anatomical or functional alterations of neuroendocrine system; thus, the study of these dysfunctions is necessary for a correct aetiopathogenetic and therapeutic framing of infertile patients. In this article, we underline the importance of the study of the molecular mechanisms regulated by the most common therapy used to treat infertile men, with the aim to highlight the necessity to avoid the administration of the wrong posology or, even more important, the wrong therapy to the patient. Accordingly, we present some pioneer data obtained on primary testicular cells cultured in vitro and treated with human chorionic gonadotropin (hCG). These data pave the way on the possibility to preliminarily test the effectiveness of the therapy in vitro, in order to identify the responsiveness of patient-derived cells to the treatment and its effectiveness in each subject, in order to identify the correct dosage in a personalised way.

Generation of a hTERT-Immortalized Human Sertoli Cell Model to Study Transporter Dynamics at the Blood-Testis Barrier

The blood-testis barrier (BTB) formed by adjacent Sertoli cells (SCs) limits the entry of many chemicals into seminiferous tubules. Differences in rodent and human substrate-transporter selectivity or kinetics can misrepresent conclusions drawn using rodent in vitro models. Therefore, human in vitro models are preferable when studying transporter dynamics at the BTB. This study describes a hTERT-immortalized human SC line (hT-SerC) with significantly increased replication capacity and minor phenotypic alterations compared to primary human SCs. Notably, hT-SerCs retained similar morphology and minimal changes to mRNA expression of several common SC genes, including AR and FSHR. The mRNA expression of most xenobiotic transporters was within the 2-fold difference threshold in RT-qPCR analysis with some exceptions (OAT3, OCT3, OCTN1, OATP3A1, OATP4A1, ENT1, and ENT2). Functional analysis of the equilibrative nucleoside transporters (ENTs) revealed that primary human SCs and hT-SerCs predominantly express ENT1 with minimal ENT2 expression at the plasma membrane. ENT1-mediated uptake of [³H] uridine was linear over 10 min and inhibited by NBMPR with an IC₅₀ value of 1.35 ± 0.37 nM. These results demonstrate that hT-SerCs can functionally model elements of transport across the human BTB, potentially leading to identification of other transport pathways for xenobiotics, and will guide drug discovery efforts in developing effective BTB-permeable compounds.

Effect of Human Testicular Cells Conditioned Medium on In Vitro Maturation and Morphology of Mouse Oocytes

Background

Testicular cell conditioned medium (TCCM) has been shown to induce female germ cell development in vitro from embryonic stem cells (ESCs). Testicular cells (TCs) secrete a variety of growth factors such as growth differentiation factor-9 (GDF-9), bone morphogenetic protein 4 (BMP-4), stem cell factor (SCF), leukemia inhibitory factor (LIF), and other, that could improve oocyte maturation. Here we have investigated the effect of human TCCM (hTCCM) on in vitro maturation (IVM) and morphology of mouse oocytes.

Materials and Methods

In this experimental study, 360 germinal vesicle (GV) oocytes were obtained from NMRI mice, aged 4-6 weeks that had received 5 IU pregnant mare's serum gonadotropin (PMSG) 48 hours before. GV oocytes were subjected to IVM. 120 GV oocytes were cultured in each medium; hTCCM as the test group, DMEM + 20%FBS as the control group and Ham’s F10 + HFF medium as the sham group. The rates of the IVM and perivi- telline space (PVS) changes were recorded at 8, 16 and 24 hours after culture. The metaphase II (MII) oocytes were subjected for in vitro fertilization (IVF) and the fertilization rate was evaluated after 1, 2, and 3 days.

Results

There was a significant difference between the maturation rates in hTCCM (31.67% MII) and the control [0% MII, P<0.05, (7.5% MI, 52.5% deg. and 40%GV)] groups but there was not a significant difference between the maturation rates in hTCCM and the sham group (53.33% MII, P>0.05). IVF success rate for MII oocytes obtained from IVM in the hTCCM group was 28.94% (n=11). Our data showed that hTCCM is an effective medium for GV oocyte growth and maturation compared to the control medium.

Conclusion

Our findings show that TCCM supports oocyte IVM in mice and affect oocyte morphology.

Gelatin Electrospun Mat as a Potential Co-culture System for In Vitro Production of Sperm Cells from Embryonic Stem Cells

Engineering of 3D substrates with maximum similarity to seminiferous tubules would help to produce functional sperm cells in vitro from stem cells. Here, we present a 3D electrospun gelatin (EG) substrate seeded with Sertoli cells and determine its potential for guided differentiation of embryonic stem cells (ESCs) toward germline cells. The EG was fabricated by electrospinning, and its morphology under SEM, as well as cytobiocompatibility for Sertoli cells and ESCs, was confirmed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and cell attachment assay. Embryoid bodies (EBs) were formed from ESCs and co-cultured with Sertoli cells, induced with BMP4 for 3 and 7 consecutive days to induce the differentiation of EBs toward germline cells. The differentiation was investigated by immunocytochemistry (ICC), flow cytometry, and RT-PCR in four experimental groups of EBs (EBs cultured in gelatin-coated cell culture plates); Scaffold/EB (EBs cultured on EG); ESCs/Ser (EBs and Sertoli cells co-cultured on gelatin-coated cell culture plates without EG); and Scaffold/EB/Ser (EBs and Sertoli cells co-cultured on EG). All experimental groups exhibited a significantly increased MVH (germline-specific marker) and decreased c-KIT (stemness marker) expression when compared with the EB group. ICC and flow cytometry revealed that Scaffold/EB/Ser had the highest level of MVH and the lowest c-KIT expression at both 3 and 7 days postdifferentiation compared with other groups. RT-PCR results showed a significant increase in the germline marker (Dazl) and a significant decrease in the ESC stemness marker (Nanog) in Scaffold/EB compared to the EB group. The germline markers Gcna, Stella, Mvh, Stra8, Piwil2, and Dazl were significantly increased in Scaffold/EB/Ser compared to the Scaffold/EB group. Our findings revealed that the EG scaffold can provide an excellent substrate biomimicking the micro/nanostructure of native seminiferous tubules and a platform for Sertoli cell-EB communication required for growth and differentiation of ESCs into germline cells.

Pig Hsd17b3: Alternative splice variants expression, insertion/deletion (indel) in promoter region and their associations with male reproductive traits

Hydroxysteroid 17-Beta Dehydrogenase 3 (Hsd17b3), primarily expressed in Leydig cells (LCs) of the mammalian testes, is essential for testosterone biosynthesis and male fertility. The aim of our study was to profile the expression, splice variants (SV) and novel insertion/deletion (indel) of Hsd17b3 in boars. Quantitative analysis showed that the expression level of Hsd17b3 in the testis was significantly highest. Among different testicular cell types, the Hsd17b3 mRNA expression level of LCs was significantly higher than that of SSCs (spermatogonial stem cells) and SCs (Sertoli cells). Furthermore, the SV was firstly identified in pigs and it was highly expressed in LCs comparing with SSCs and SCs. In addition, two mutations were identified in pig Hsd17b3 gene promotor and intron, respectively, which were associated with male reproductive traits (P <  0.05). In conclusion, both transcripts of Hsd17b3 gene were highly expressed in pig testes and LCs; the two novel indel variants of Hsd17b3 gene can be used as potential DNA makers for the marker-assisted selection in pigs. All these findings would enrich the study of Hsd17b3 gene in pig genetic breeding.

Mechanistic Insights into PFOS-Mediated Sertoli Cell Injury

Studies have proven that per- and polyfluoroalkyl substances are harmful to humans, most notably perfluorooctanesulfonate (PFOS). PFOS induces rapid disorganization of actin- and microtubule (MT)-based cytoskeletons in primary cultures of rodent and human Sertoli cells, perturbing Sertoli cell gap junction communication, thereby prohibiting Sertoli cells from maintaining cellular homeostasis in the seminiferous epithelium to support spermatogenesis. PFOS perturbs several signaling proteins/pathways, such as FAK and mTORC1/rpS6/Akt1/2. The use of either an activator of Akt1/2 or overexpression of a phosphomimetic (and constitutively active) mutant of FAK or connexin 43 has demonstrated that such treatment blocks PFOS-induced Sertoli cell injury by preventing actin- and MT-based cytoskeletal disorganization. These findings thus illustrate an approach to manage PFOS-induced reproductive dysfunction.