Activins in reproductive biology and beyond

Management of pulmonary hypertension in special conditions

Care of pulmonary hypertension (PH) patients in special situations requires insightful knowledge of the pathophysiology of the cardiopulmonary system and close interaction with different specialists, depending on the situation. The role of this task force was to gather knowledge about five conditions that PH patients may be faced with. These conditions are 1) perioperative care; 2) management of pregnancy; 3) medication adherence; 4) palliative care; and 5) the influence of climate on PH. Many of these aspects have not been covered by previous World Symposia on Pulmonary Hypertension. All of the above conditions are highly affected by psychological, geographical and socioeconomic factors, and share the need for adequate healthcare provision. The task force identified significant gaps in information and research in these areas. The current recommendations are based on detailed literature search and expert opinion. The task force calls for further studies and research to better understand and address the special circumstances that PH patients may encounter.

Relative Energy Deficiency in Sport (REDs): Endocrine Manifestations, Pathophysiology and Treatments

Research on lean, energy-deficient athletic and military cohorts has broadened the concept of the Female Athlete Triad into the Relative Energy Deficiency in Sport (REDs) syndrome. REDs represents a spectrum of abnormalities induced by low energy availability (LEA), which serves as the underlying cause of all symptoms described within the REDs concept, affecting exercising populations of either biological sex. Both short- and long-term LEA, in conjunction with other moderating factors, may produce a multitude of maladaptive changes that impair various physiological systems and adversely affect health, well-being, and sport performance. Consequently, the comprehensive definition of REDs encompasses a broad spectrum of physiological sequelae and adverse clinical outcomes related to LEA, such as neuroendocrine, bone, immune, and hematological effects, ultimately resulting in compromised health and performance. In this review, we discuss the pathophysiology of REDs and associated disorders. We briefly examine current treatment recommendations for REDs, primarily focusing on nonpharmacological, behavioral, and lifestyle modifications that target its underlying cause-energy deficit. We also discuss treatment approaches aimed at managing symptoms, such as menstrual dysfunction and bone stress injuries, and explore potential novel treatments that target the underlying physiology, emphasizing the roles of leptin and the activin-follistatin-inhibin axis, the roles of which remain to be fully elucidated, in the pathophysiology and management of REDs. In the near future, novel therapies leveraging our emerging understanding of molecules and physiological axes underlying energy availability or lack thereof may restore LEA-related abnormalities, thus preventing and/or treating REDs-related health complications, such as stress fractures, and improving performance.

The Concentration of Follistatin and Activin A in Serum and Selected Biochemical Parameters in Women with Polycystic Ovary Syndrome: Stratification by Tobacco Smoke Exposure, Insulin Resistance, and Overweight/Obesity

Background/Objectives: The aim of the study was to investigate the concentrations of follistatin and activin A in the serum of women with polycystic ovary syndrome (PCOS) and to assess their relationship with selected biochemical parameters, specifically stratifying the analysis based on tobacco smoke, insulin resistance, and abnormal weight. Methods: The research was carried out within a cohort of 88 women (60 women with and 28 without PCOS). Results: We observed significant differences (p < 0.05) in follistatin concentrations between women with PCOS stratified by homeostatic model assessment for insulin resistance (HOMA-IR) values. These differences were consistent across both smoking and non-smoking subgroups with PCOS. Similar results were observed when comparing normal-weight women with PCOS to those with overweight or obesity. Additionally, activin A concentrations were significantly increased by higher body mass index (BMI) and HOMA-IR values in non-smoking women with PCOS. Moreover, we identified a negative correlation (r = -0.30; p < 0.023) between cotinine levels and Anti-Müllerian hormone. Among smoking women with PCOS, we noted decreased concentrations of sex hormone-binding globulin and high-density lipoproteins, alongside increased fasting glucose, insulin, HOMA-IR, and free androgen index values. Conclusions: Our findings suggest that activin A and follistatin concentrations are more strongly influenced by disruptions in glucose metabolism and BMI than by tobacco smoke exposure. The observed changes were more pronounced in follistatin than in activin A level.

Pronounced early differentiation underlies zebra finch gonadal germ cell development

The diversity of germ cell developmental strategies has been well documented across many vertebrate clades. However, much of our understanding of avian primordial germ cell (PGC) specification and differentiation has derived from only one species, the chicken (Gallus gallus). Of the three major classes of birds, chickens belong to Galloanserae, representing less than 4% of species, while nearly 95% of extant bird species belong to Neoaves. This represents a significant gap in our knowledge of germ cell development across avian species, hampering efforts to adapt genome editing and reproductive technologies developed in chicken to other birds. We therefore applied single-cell RNA sequencing to investigate inter-species differences in germ cell development between chicken and zebra finch (Taeniopygia castanotis), a Neoaves songbird species and a common model of vocal learning. Analysis of early embryonic male and female gonads revealed the presence of two distinct early germ cell types in zebra finch and only one in chicken. Both germ cell types expressed zebra finch Germline Restricted Chromosome (GRC) genes, present only in songbirds among birds. One of the zebra finch germ cell types expressed the canonical PGC markers, as did chicken, but with expression differences in several signaling pathways and biological processes. The second zebra finch germ cell cluster was marked by proliferation and fate determination markers, indicating beginning of differentiation. Notably, these two zebra finch germ cell populations were present in both male and female zebra finch gonads as early as HH25. Using additional chicken developmental stages, similar germ cell heterogeneity was identified in the more developed gonads of females, but not males. Overall, our study demonstrates a substantial heterochrony in zebra finch germ cell development compared to chicken, indicating a richer diversity of avian germ cell developmental strategies than previously known.

Proteome and metabolomic profile of Mongolian horse follicular fluid during follicle development

During follicular development, changes in the composition of the follicular fluid are synchronized with the development of oocytes. Our aim was to screen the key factors affecting oocyte maturation and optimize the in vitro culture protocol by understanding the changes of proteins and metabolites in follicular fluid. Follicles are divided into three groups according to their diameter (small follicle fluid (SFF): 10 mm < d < 20 mm; medium follicle fluid (MFF): 20 mm < d < 30 mm; large follicle fluid (LFF): 30 mm < d). Proteins and metabolites from the follicular fluid were analyzed by mass spectrometry. The results showed that: in LFF vs MFF, 20 differential abundant protein (DAP) and 88 differential abundant metabolites (DAM) were screened out; In SFF vs MFF, 3 DAPs and 65 DAMs were screened out; In MFF vs SFF, 24 DAPs and 35 DAMs were screened out. The analysis of differential proteins and metabolites showed that glycerophosphate hydrolysis decreased during follicular development, and proteins played a major role in metabolism and binding. In addition, DAMs and DAPs are co-enriched in the "linoleic acid metabolism" pathway. Combinatorial analysis reveals the dynamic profile of follicular fluid during follicular development and provides fundation for further exploring the function of follicular fluid in Mongolian horse.

Inhibin subunit beta B (INHBB): an emerging role in tumor progression

The gene inhibin subunit beta B (INHBB) encodes the inhibin βB subunit, which is involved in forming protein members of the transforming growth factor-β (TGF-β) superfamily. The TGF-β superfamily is extensively involved in cell proliferation, differentiation, adhesion, movement, metabolism, communication, and death. Activins and inhibins, which belong to the TGF-β superfamily, were first discovered in ovarian follicular fluid. They were initially described as regulators of pituitary follicle-stimulating hormone (FSH) secretion both in vivo and in vitro. Later studies found that INHBB is expressed not only in reproductive organs such as the ovary, uterus, and testis but also in numerous other organs, including the brain, spinal cord, liver, kidneys, and adrenal glands. This wide distribution implies its involvement in the normal physiological functions of various organs; however, the mechanisms underlying these functions have not yet been fully elucidated. Recent studies suggest that INHBB plays a significant, yet complex role in tumorigenesis. It appears to have dual effects, promoting tumor progression in some contexts while inhibiting it in others, although these roles are not yet fully understood. In this paper, we review the different expression patterns, functions, and mechanisms of INHBB in normal and tumor tissues to illustrate the research prospects of INHBB in tumor progression.

Identification of ActivinβA and Gonadotropin Regulation of the Activin System in the Ovary of Chinese Sturgeon Acipenser sinensis

Activin is a dimeric growth factor with diverse biological activities in vertebrates. This study aimed to investigate the regulatory role of the activin signaling pathway in the ovary of the endangered, cultured sturgeon species Acipenser sinensis. One activinβA subunit was identified, with a full-length complementary DNA (cDNA) sequence of 1572 base pairs. Multiple sequence alignment suggested that ActivinβA shared high sequence identities with its counterparts in four other sturgeon species. Phylogenetic analysis indicated the conserved evolution of ActivinβA among vertebrates from mammals to fish species. Transcripts of activinβA were distributed ubiquitously in the liver, kidney, intestine, ovary, midbrain, hypothalamus, and pituitary, with the highest transcription found in the pituitary. In Chinese sturgeon ovarian cells, in vitro human recombinant Activin A incubation stimulated the activin system-related gene transcriptions of activinβA, follistatin, its receptors -activinRIIA and activinRIIB, and drosophila mothers against decapentaplegic proteins (smads) smad2, smad3, and smad4. Ovary development-related mRNA levels of cyp19a1a and aromatase receptors of erα and erβ were enhanced by Activin A or human chorionic gonadotropin (hCG) incubation. Furthermore, 15 IU/mL hCG treatment increased the transcription levels of activinβA, follistatin, activinRIIA, and smad2. This suggested that the activin system was functional for the regulation of ovary development in Chinese sturgeon, possibly under the regulation of gonadotropin, by recruiting activinβA, follistatin, activinRIIA, and smad2. These results were helpful for the molecular exploration of activin signaling in fish species, as well as the ovarian maturation regulation of A. sinensis.

New aspects of activin biology in epididymal function and immunopathology

The activins (A and B) and their binding protein, follistatin, play crucial roles in development, immunoregulation and inflammation throughout the body. In the male reproductive tract of the mouse, activin A and B production is largely confined to the initial segment and proximal caput of the epididymis and the efferent ducts, under normal conditions, with very low expression in the corpus, cauda and vas deferens. However, activin A protein is present throughout the epididymis and vas deferens and is largely associated with the epithelium and interstitial macrophages. Conversely, the activin-binding protein follistatin is produced in the distal epididymis, with very high expression in the vas deferens. Activin activity in the distal tract is inhibited by follistatin, and the activin-follistatin balance is important for regulating coiling of the duct during epididymal development. In further experiments, as described in this report, in situ hybridisation was used to localise activin A mRNA principally to cells in the periductal zone and interstitium in the efferent ducts and proximal caput. Activin B mRNA, on the other hand, was localised to periductal cells in the efferent ducts and proximal epididymis and, most notably, to epithelial cells in the initial segment. Activin A is implicated in the regulation of mononuclear phagocyte function and immune responses in the caput and stimulates the expression of the key immunoregulatory protein, indoleamine 2,3-dioxygenase in this region. Activin A production in the corpus and cauda increases dramatically during bacterial epididymitis in mice, promoting inflammation and fibrosis and causing damage to the epithelium and obstruction of the epididymal duct. Consequently, it appears that the activin-follistatin axis is crucial for maintaining normal epididymal structure and function, but disruption of this balance during inflammation has deleterious effects on male fertility. Follistatin has therapeutic potential in ameliorating the proinflammatory and profibrotic effects of activins.

The role of the oviduct environment in embryo survival

CONTEXT

Declining fertility is an issue in multiple mammalian species. As the site of fertilisation and early embryo development, the oviduct plays a critical role in embryo survival, yet there is a paucity of information on how the oviduct regulates this process.

AIMS

We hypothesised that differences in steroid hormone signalling and/or immune function would be observed in a model of poor embryo survival, the peripubertal ewe.

METHODS

We examined expression of steroid hormones in systemic circulation, oviductal expression of oestrogen receptorαand genes important in steroid hormone signalling, and immune function in pregnant and cyclic peripubertal and adult ewes on day 3 after oestrus.

KEY RESULTS

Concentrations of progesterone, but not oestradiol, were decreased in the peripubertal ewe compared to the adult ewe. Oestrogen receptorαprotein expression was increased in the peripubertal ewe, but pathway analysis of gene expression revealed downregulation of the oestrogen signalling pathway compared to the adult ewe. Differential expression of several genes involved in immune function between the peripubertal and adult ewe was consistent with an unfavourable oviductal environment in the peripubertal ewe lamb. Oestradiol concentration was positively correlated with the expression of multiple genes involved in the regulation of immune function.

CONCLUSIONS

Differences in the immune environment of the oviduct, potentially linked to differential modulation by steroid hormones, may partially underly the poor fertilisation and early embryo survival observed in the peripubertal ewe.

IMPLICATIONS

A unfavourable oviductal environment may play an important role in limiting reproductive success.

Transcriptome Analysis of Key Genes Involved in the Initiation of Spermatogonial Stem Cell Differentiation

PURPOSE

The purpose of this study was to screen the genes and pathways that are involved in spermatogonia stem cell (SSC) differentiation regulation during the transition from Aundiff to A1. Methods: RNA sequencing was performed to screen differentially expressed genes at 1 d and 2 d after SSC differentiation culture. KEGG pathway enrichment and GO function analysis were performed to reveal the genes and pathways related to the initiation of early SSC differentiation.

RESULTS

The GO analysis showed that Rpl21, which regulates cell differentiation initiation, significantly increased after 1 day of SSC differentiation. The expressions of Fn1, Cd9, Fgf2, Itgb1, Epha2, Ctgf, Cttn, Timp2 and Fgfr1, which are related to promoting differentiation, were up-regulated after 2 days of SSC differentiation. The analysis of the KEGG pathway revealed that RNA transport is the most enriched pathway 1 day after SSC differentiation. Hspa2, which promotes the differentiation of male reproductive cells, and Cdkn2a, which participates in the cell cycle, were significantly up-regulated. The p53 pathway and MAPK pathway were the most enriched pathways 2 days after SSC differentiation. Cdkn1a, Hmga2, Thbs1 and Cdkn2a, microRNAs that promote cell differentiation, were also significantly up-regulated.

CONCLUSIONS

RNA transport, the MAPK pathway and the p53 pathway may play vital roles in early SSC differentiation, and Rpl21, Fn1, Cd9, Fgf2, Itgb1, Epha2, Ctgf, Cttn, Timp2, Fgfr1, Hspa2, Cdkn2a, Cdkn1a, Hmga2 and Thbs1 are involved in the initiation of SSC differentiation. The findings of this study provide a reference for further revelations of the regulatory mechanism of SSC differentiation.

Evaluation of the prognostic and therapeutic potential of inhibin beta B for oral squamous cell carcinoma

Background/purpose

Oral squamous cell carcinoma (OSCC) is a common cancer worldwide, and its metastasis is difficult to predict and prevent. Inhibin beta B (INHBB) protein has been linked to cancer prognosis and epithelial-mesenchymal transition (EMT). However, previous study about INHBB expression focused on patients in a single region while the risk factors vary among regions. This study aimed to provide a broader perspective on INHBB expression in OSCC.

Materials and methods

Tissue micro-arrays comprising 118 specimens were subjected to immunohistochemistry, and all slides were quantified using StrataQuest software.

Results

The ratio of INHBB-positive cells to total cells was significantly higher in OSCC samples than in normal samples, and the intensity of INHBB expression was significantly greater in the late-stage OSCC. After classifying specimens into high and low INHBB expression groups, a significant association with clinical staging was found. Though a previous study suggested that menin regulates INHBB, menin expression was not detected in specimens.

Conclusion

The ratio of INHBB-positive cells in OSCC may be druggable for targeting tumor cells or assisting in diagnosis, and the intensity of INHBB expression may provide prognostic information for predicting potential metastasis. Moreover, the regulatory mechanism of INHBB in OSCC remains unclear and requires further investigation.

Immunolocalization of activin and inhibin at different stages of follicular development in the lizard Sceloporus torquatus

The activins and inhibins are glycoproteins with a role in the follicular development of vertebrates, that are found in follicular fluid and somatic follicular cells, with a different pattern among taxa. The principal function of activin (Act) is to modulate the follicle-stimulating hormone (FSH) synthesis and secretion, whereas inhibin (Inh) downregulates it. Both factors are modulators of intraovarian follicular recruitment, oocyte maturation, cell proliferation, and steroidogenic activity. Our aim was to characterize the immunolocalization of Act and Inh in the ovarian follicles during the reproductive cycle of the lizard Sceloporus torquatus. Act was detected in the granulosa cells and oocyte cortex in the different stages of follicular development. On the other hand, we identified Inh in the oocyte cortex and the cytoplasm of pyriform and small cells of previtellogenic follicles. Also, we found immunoreactivity in the oocyte cortex, theca, and small cells of vitellogenic and preovulatory follicles. Our data provide evidence that Act and Inh have changes related to the stage of follicular development. This dynamic appears to be conserved among vertebrates and is fundamental to ensure an adequate follicular development in this specie.

Menstrual Blood-Derived Stem Cell Paracrine Factors Possess Stimulatory Effects on Chondrogenesis In Vitro and Diminish the Degradation of Articular Cartilage during Osteoarthritis

Articular cartilage is an avascular tissue with a limited capacity for self-regeneration, leading the tissue to osteoarthritis (OA). Mesenchymal stem cells (MSCs) are promising for cartilage tissue engineering, as they are capable of differentiating into chondrocyte-like cells and secreting a number of active molecules that are important for cartilage extracellular matrix (ECM) synthesis. The aim of this study was to evaluate the potential of easily accessible menstrual blood-derived MSC (MenSC) paracrine factors in stimulating bone marrow MSC (BMMSCs) chondrogenic differentiation and to investigate their role in protecting cartilage from degradation in vitro. MenSCs and BMMSCs chondrogenic differentiation was induced using four different growth factors: TGF-β3, activin A, BMP-2, and IGF-1. The chondrogenic differentiation of BMMSCs was stimulated in co-cultures with MenSCs and cartilage explants co-cultured with MenSCs for 21 days. The chondrogenic capacity of BMMSCs was analyzed by the secretion of four growth factors and cartilage oligomeric matrix protein, as well as the release and synthesis of cartilage ECM proteins, and chondrogenic gene expression in cartilage explants. Our results suggest that MenSCs stimulate chondrogenic response in BMMSCs by secreting activin A and TGF-β3 and may have protective effects on cartilage tissue ECM by decreasing the release of GAGs, most likely through the modulation of activin A related molecular pathway. In conclusion, paracrine factors secreted by MenSCs may turn out to be a promising therapeutical approach for cartilage tissue protection and repair.

Exploring the presence of markers of decidualization in the fallopian tubes: a systematic review

The fallopian tubes (FTs) are part of the female upper genital tract. The healthy FT provides the biological environment for successful fertilization and facilitates the subsequent movement of the conceptus to the endometrial cavity. However, when the FT is damaged, as with salpingitis, pyosalpinx, and hydrosalpinx, it may increase the risk of an ectopic pregnancy, a life-threatening condition. Decidualization refers to a multifactorial process by which the endometrium changes to permit blastocyst implantation. The decidualization reaction is vital for endometrial receptivity during the window of implantation. To date, no comprehensive review that collates evidence on decidualization in the human FT has been conducted. Therefore, the aim of this review is to compile the current evidence on cellular decidualization occurring in the healthy and pathological FT in women of reproductive age. A literature search was conducted using five databases and identified 746 articles, 24 of which were analyzed based on inclusion and exclusion criteria. The available evidence indicates that the FT are able to undergo decidual changes under specific circumstances; however, the exact mechanism by which this occurs is poorly understood. Further research is needed to elucidate the mechanism by which decidualization can occur in the FT.

Spermatogonial fate in mice with increased activin A bioactivity and testicular somatic cell tumours

Adult male fertility depends on spermatogonial stem cells (SSCs) which undergo either self-renewal or differentiation in response to microenvironmental signals. Activin A acts on Sertoli and Leydig cells to regulate key aspects of testis development and function throughout life, including steroid production. Recognising that activin A levels are elevated in many pathophysiological conditions, this study investigates effects of this growth factor on the niche that determines spermatogonial fate. Although activin A can promote differentiation of isolated spermatogonia in vitro, its impacts on SSC and spermatogonial function in vivo are unknown. To assess this, we examined testes of Inha KO mice, which feature elevated activin A levels and bioactivity, and develop gonadal stromal cell tumours as adults. The GFRA1+ SSC-enriched population was more abundant and proliferative in Inha KO compared to wildtype controls, suggesting that chronic elevation of activin A promotes a niche which supports SSC self-renewal. Intriguingly, clusters of GFRA1+/EOMES+/LIN28A- cells, resembling a primitive SSC subset, were frequently observed in tubules adjacent to tumour regions. Transcriptional analyses of Inha KO tumours, tubules adjacent to tumours, and tubules distant from tumour regions revealed disrupted gene expression in each KO group increased in parallel with tumour proximity. Modest transcriptional changes were documented in Inha KO tubules with complete spermatogenesis. Importantly, tumours displaying upregulation of activin responsive genes were also enriched for factors that promote SSC self-renewal, including Gdnf, Igf1, and Fgf2, indicating the tumours generate a supportive microenvironment for SSCs. Tumour cells featured some characteristics of adult Sertoli cells but lacked consistent SOX9 expression and exhibited an enhanced steroidogenic phenotype, which could arise from maintenance or acquisition of a fetal cell identity or acquisition of another somatic phenotype. Tumour regions were also heavily infiltrated with endothelial, peritubular myoid and immune cells, which may contribute to adjacent SSC support. Our data show for the first time that chronically elevated activin A affects SSC fate in vivo. The discovery that testis stromal tumours in the Inha KO mouse create a microenvironment that supports SSC self-renewal but not differentiation offers a strategy for identifying pathways that improve spermatogonial propagation in vitro.

Establishment of the fetal-maternal interface: developmental events in human implantation and placentation

Early pregnancy is a complex and well-orchestrated differentiation process that involves all the cellular elements of the fetal-maternal interface. Aberrant trophoblast-decidual interactions can lead to miscarriage and disorders that occur later in pregnancy, including preeclampsia, intrauterine fetal growth restriction, and preterm labor. A great deal of research on the regulation of implantation and placentation has been performed in a wide range of species. However, there is significant species variation regarding trophoblast differentiation as well as decidual-specific gene expression and regulation. Most of the relevant information has been obtained from studies using mouse models. A comprehensive understanding of the physiology and pathology of human implantation and placentation has only recently been obtained because of emerging advanced technologies. With the derivation of human trophoblast stem cells, 3D-organoid cultures, and single-cell analyses of differentiated cells, cell type-specific transcript profiles and functions were generated, and each exhibited a unique signature. Additionally, through integrative transcriptomic information, researchers can uncover the cellular dysfunction of embryonic and placental cells in peri-implantation embryos and the early pathological placenta. In fact, the clinical utility of fetal-maternal cellular trafficking has been applied for the noninvasive prenatal diagnosis of aneuploidies and the prediction of pregnancy complications. Furthermore, recent studies have proposed a viable path toward the development of therapeutic strategies targeting placenta-enriched molecules for placental dysfunction and diseases.

Postprandial secretion of follistatin after gastric bypass surgery and sleeve gastrectomy

Follistatin is secreted from the liver and may regulate muscle growth and insulin sensitivity. Protein intake stimulates follistatin secretion, which may be mediated by increased glucagon in the context of low insulin concentrations. We investigated circulating follistatin after mixed-meals in two cohorts of patients who were part of previously published studies and had undergone bariatric surgery with either simultaneous assessment of amino acid absorption or administration of the GLP-1 receptor antagonist exendin-(9-39), which increased glucagon concentrations and impaired insulin secretion. Study 1 comprised obese matched subjects with previous Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery and unoperated controls who underwent 6-hour mixed-meal tests with intravenous and oral tracers including intrinsically labelled caseinate in the meal. Study 2 comprised obese subjects with previous RYGB who underwent two 5-hour mixed-meal tests with concomitant exendin-(9-39) or saline infusion. In study 1, the secretion of follistatin as well as the amino acid absorption was accelerated after RYGB compared with SG and controls, but the glucagon-to-C-peptide ratios did not differ between the groups. In study 2, exendin-(9-39) administration increased postprandial glucagon concentrations and lowered insulin secretion, whereas the concentration of follistatin was unchanged. In conclusion, postprandial follistatin secretion is accelerated in patients after RYGB which might be explained by an accelerated protein absorption rate rather than the glucagon-to-insulin ratio.

Fractalkine Improves the Expression of Endometrium Receptivity-Related Genes and Proteins at Desferrioxamine-Induced Iron Deficiency in HEC-1A Cells

Fractalkine (CX3CL1/FKN) is a unique chemokine belonging to the CX3C chemokine subclass. FKN exists in two forms: a membrane-bound form expressed by both endometrium cells and trophoblasts thought to be implicated in maternal-fetal interaction and a soluble form expressed by endometrium cells. Endometrium receptivity is crucial in embryo implantation and a complex process regulated by large numbers of proteins, e.g., cytokines, progesterone receptor (PR), SOX-17, prostaglandin receptors (PTGER2), and tissue inhibitors of metalloproteinases (TIMPs). It has also been reported that iron is important in fertility and affects the iron status of the mother. Therefore, iron availability in the embryo contributes to fertilization and pregnancy. In this study, we focused on the effect of iron deficiency on the secreted cytokines (IL-6, IL-1β, leukocyte inhibitory factor, TGF-β), chemokines (IL-8, FKN), and other regulatory proteins (bone morphogenic protein 2, activin, follistatin, PR, SOX-17, prostaglandin E2 receptor, TIMP2), and the modifying effect of FKN on the expression of these proteins, which may improve endometrium receptivity. Endometrial iron deficiency was mediated by desferrioxamine (DFO) treatment of HEC-1A cells. FKN was added to the cells 24 h and 48 h after DFO with or without serum for modelling the possible iron dependence of the alterations. Our findings support the hypothesis that FKN ameliorates the effects of anemia on the receptivity-related genes and proteins in HEC-1A cells by increasing the secretion of the receptivity-related cytokines via the fractalkine receptor (CX3CR1). FKN may contribute to cell proliferation and differentiation by regulating activin, follistatin, and BMP2 expressions, and to implantation by altering the protein levels of PR, SOX-17, PTGER2, and TIMP2. FKN mitigates the negative effect of iron deficiency on the receptivity-related genes and proteins of HEC-1A endometrium cells, suggesting its important role in the regulation of endometrium receptivity.

Immunostaining of βA-Activin and Follistatin Is Decreased in HPV(+) Cervical Pre-Neoplastic and Neoplastic Lesions

The activin-follistatin system regulates several cellular processes, including differentiation and tumorigenesis. We hypothesized that the immunostaining of βA-activin and follistatin varies in neoplastic cervical lesions. Cervical paraffin-embedded tissues from 162 patients sorted in control (n = 15), cervical intraepithelial neoplasia (CIN) grade 1 (n = 38), CIN2 (n = 37), CIN3 (n = 39), and squamous cell carcinoma (SCC; n = 33) groups were examined for βA-activin and follistatin immunostaining. Human papillomavirus (HPV) detection and genotyping were performed by PCR and immunohistochemistry. Sixteen samples were inconclusive for HPV detection. In total, 93% of the specimens exhibited HPV positivity, which increased with patient age. The most detected high-risk (HR)-HPV type was HPV16 (41.2%) followed by HPV18 (16%). The immunostaining of cytoplasmatic βA-activin and follistatin was higher than nuclear immunostaining in all cervical epithelium layers of the CIN1, CIN2, CIN3, and SCC groups. A significant decrease (p < 0.05) in the cytoplasmic and nuclear immunostaining of βA-activin was detected in all cervical epithelial layers from the control to the CIN1, CIN2, CIN3, and SCC groups. Only nuclear follistatin immunostaining exhibited a significant reduction (p < 0.05) in specific epithelial layers of cervical tissues from CIN1, CIN2, CIN3, and SCC compared to the control. Decreased immunostaining of cervical βA-activin and follistatin at specific stages of CIN progression suggests that the activin-follistatin system participates in the loss of the differentiation control of pre-neoplastic and neoplastic cervical specimens predominantly positive for HPV.

INHBB promotes tumor aggressiveness and stemness of glioblastoma via activating EGFR signaling

BACKGROUND

As most common primary tumor in adult's brain, the glioblastoma (GBM) still ends up with poor survival period. Little progress has been made in recent decades in terms of improving prognosis. There's still an urgent need for novel targets and strategies to overcome such malignancy.

METHODS

Both the Cancer Genome Atlas and Gene Expression Omnibus databases were used to analyze expression differences and correlations. The immunohistochemistry and survival analysis were used to verify expression differences. Tumorigenesis was assessed using cholecystokinin and the orthotopic xenograft model. Metastasis was determined by the transwell assay and the tail vein xenograft model.

RESULTS

Inhibin subunit beta B (INHBB) was upregulated in GBM and predicted poor survival. It promoted tumor growth, invasion and stemness in GBM. INHBB expression correlated with the epidermal growth factor receptor (EGFR) expression and downstream AKT and ERK expression levels. The increased tumor progression induced by INHBB could be inhibited by afatinib.

CONCLUSION

This study revealed INHBB as a tumor progression and independent prognostic factor in GBM, which could be a potential upper stream molecular of EGFR/ERK/AKT signaling.

Activin A and pathologies of pregnancy: a review

Activin A is a two-subunit protein belonging to the transforming growth factor β superfamily. First discovered almost three decades ago, it has since been implicated in diverse physiological roles, ranging from wound repair to reproduction. After 30 years of research, altered activin A levels are now understood to be associated with the development of various diseases, making activin A a potential therapeutic target. In pregnancy, the placenta and fetal membranes are major producers of activin A, with significantly enhanced serum concentrations now recognised as a contributor to numerous gestational disorders. Evidence now suggests that circulating levels of activin A may be clinically relevant in the early detection of pregnancy complications, including miscarriage and preeclampsia. This review aims to summarise our current understanding of activin A as a potential diagnostic marker in common pregnancy pathologies.

Adiponectin, the adiponectin paradox, and Alzheimer's Disease: Is this association biologically plausible?

Dementia, especially Alzheimer's Disease (AD) and vascular dementia, is a major public health problem that continues to expand in both economically emerging and hegemonic countries. In 2017, the World Alzheimer Report estimated that over 50 million people were living with dementia globally. Metabolic dysfunctions of brain structures such as the hippocampus and cerebral cortex have been implicated as risk factors for dementia. Several well-defined metabolic risk factors for AD include visceral obesity, chronic inflammation, peripheral and brain insulin resistance, type 2 diabetes mellitus (T2DM), hypercholesterolemia, and others. In this review, we describe the relationship between the dysmetabolic mechanisms, although still unknown, and dementia, particularly AD. Adiponectin (ADPN), the most abundant circulating adipocytokine, acts as a protagonist in the metabolic dysfunction associated with AD, with unexpected and intriguing dual biological functions. This contradictory role of ADPN has been termed the adiponectin paradox. Some evidence suggests that the adiponectin paradox is important in amyloidogenic evolvability in AD. We present cumulative evidence showing that AD and T2DM share many common features. We also review the mechanistic pathways involving brain insulin resistance. We discuss the importance of the evolvability of amyloidogenic proteins (APs), defined as the capacity of a system for adaptive evolution. Finally, we describe potential therapeutic strategies in AD, based on the adiponectin paradox.

Overview of single-cell RNA sequencing analysis and its application to spermatogenesis research

Background

Single-cell transcriptomics allows parallel analysis of multiple cell types in tissues. Because testes comprise somatic cells and germ cells at various stages of spermatogenesis, single-cell RNA sequencing is a powerful tool for investigating the complex process of spermatogenesis. However, single-cell RNA sequencing analysis needs extensive knowledge of experimental technologies and bioinformatics, making it difficult for many, particularly experimental biologists and clinicians, to use it.

Methods

Aiming to make single-cell RNA sequencing analysis familiar, this review article presents an overview of experimental and computational methods for single-cell RNA sequencing analysis with a history of transcriptomics. In addition, combining the PubMed search and manual curation, this review also provides a summary of recent novel insights into human and mouse spermatogenesis obtained using single-cell RNA sequencing analyses.

Main Findings

Single-cell RNA sequencing identified mesenchymal cells and type II innate lymphoid cells as novel testicular cell types in the adult mouse testes, as well as detailed subtypes of germ cells. This review outlines recent discoveries into germ cell development and subtypes, somatic cell development, and cell-cell interactions.

Conclusion

The findings on spermatogenesis obtained using single-cell RNA sequencing may contribute to a deeper understanding of spermatogenesis and provide new directions for male fertility therapy.

Follistatin is a crucial chemoattractant for mouse decidualized endometrial stromal cell migration by JNK signalling

Follistatin (FST) and activin A as gonadal proteins exhibit opposite effects on follicle-stimulating hormone (FSH) release from pituitary gland, and activin A-FST system is involved in regulation of decidualization in reproductive biology. However, the roles of FST and activin A in migration of decidualized endometrial stromal cells are not well characterized. In this study, transwell chambers and microfluidic devices were used to assess the effects of FST and activin A on migration of decidualized mouse endometrial stromal cells (d-MESCs). We found that compared with activin A, FST exerted more significant effects on adhesion, wound healing and migration of d-MESCs. Similar results were also seen in the primary cultured decidual stromal cells (DSCs) from uterus of pregnant mouse. Simultaneously, the results revealed that FST increased calcium influx and upregulated the expression levels of the migration-related proteins MMP9 and Ezrin in d-MESCs. In addition, FST increased the level of phosphorylation of JNK in d-MESCs, and JNK inhibitor AS601245 significantly attenuated FST action on inducing migration of d-MESCs. These data suggest that FST, not activin A in activin A-FST system, is a crucial chemoattractant for migration of d-MESCs by JNK signalling to facilitate the successful uterine decidualization and tissue remodelling during pregnancy.

An IGF1-expressing endometrial stromal cell population is associated with human decidualization

BACKGROUND

Decidualization refers to the process of transformation of endometrial stromal fibroblast cells into specialized decidual stromal cells that provide a nutritive and immunoprivileged matrix essential for blastocyst implantation and placental development. Deficiencies in decidualization are associated with a variety of pregnancy disorders, including female infertility, recurrent implantation failure (RIF), and miscarriages. Despite the increasing number of genes reportedly associated with endometrial receptivity and decidualization, the cellular and molecular mechanisms triggering and underlying decidualization remain largely unknown. Here, we analyze single-cell transcriptional profiles of endometrial cells during the window of implantation and decidual cells of early pregnancy, to gains insights on the process of decidualization.

RESULTS

We observed a unique IGF1⁺ stromal cell that may initiate decidualization by single-cell RNA sequencing. We found the IL1B⁺ stromal cells promote gland degeneration and decidua hemostasis. We defined a subset of NK cells for accelerating decidualization and extravillous trophoblast (EVT) invasion by AREG-IGF1 and AREG-CSF1 regulatory axe. Further analysis indicates that EVT promote decidualization possibly by multiply pathways. Additionally, a systematic repository of cell-cell communication for decidualization was developed. An aberrant ratio conversion of IGF1⁺ stromal cells to IGF1R⁺ stromal cells is observed in unexplained RIF patients.

CONCLUSIONS

Overall, a unique subpopulation of IGF1⁺ stromal cell is involved in initiating decidualization. Our observations provide deeper insights into the molecular and cellular characterizations of decidualization, and a platform for further development of evaluation of decidualization degree and treatment for decidualization disorder-related diseases.

Single-cell RNA sequencing uncovers dynamic roadmap and cell-cell communication during buffalo spermatogenesis

Spermatogenesis carries the task of precise intergenerational transmission of genetic information from the paternal genome and involves complex developmental processes regulated by the testicular microenvironment. Studies performed mainly in mouse models have established the theoretical basis for spermatogenesis, yet the wide interspecies differences preclude direct translation of the findings, and farm animal studies are progressing slowly. More than 32,000 cells from prepubertal (3-month-old) and pubertal (24-month-old) buffalo testes were analyzed by using single-cell RNA sequencing (scRNA-seq), and dynamic gene expression roadmaps of germ and somatic cell development were generated. In addition to identifying the dynamic processes of sequential cell fate transitions, the global cell-cell communication essential to maintain regular spermatogenesis in the buffalo testicular microenvironment was uncovered. The findings provide the theoretical basis for establishing buffalo germline stem cells in vitro or culturing organoids and facilitating the expansion of superior livestock breeding.

Activin A and CCR2 regulate macrophage function in testicular fibrosis caused by experimental autoimmune orchitis

Experimental autoimmune-orchitis (EAO), a rodent model of chronic testicular inflammation and fibrosis, replicates pathogenic changes seen in some cases of human spermatogenic disturbances. During EAO, increased levels of pro-inflammatory and pro-fibrotic mediators such as TNF, CCL2, and activin A are accompanied by infiltration of leukocytes into the testicular parenchyma. Activin A levels correlate with EAO severity, while elevated CCL2 acting through its receptor CCR2 mediates leukocyte trafficking and recruits macrophages. CCR2 + CXCR4 + macrophages producing extracellular matrix proteins contribute widely to fibrogenesis. Furthermore, testicular macrophages (TMs) play a critical role in organ homeostasis. Therefore, we aimed to investigate the role of the activin A/CCL2-CCR2/macrophage axis in the development of testicular fibrosis. Following EAO induction, we observed lower levels of organ damage, collagen deposition, and leukocyte infiltration (including fibronectin+, collagen I+ and CXCR4+ TMs) in Ccr2-/- mice than in WT mice. Furthermore, levels of Il-10, Ccl2, and the activin A subunit Inhba mRNAs were lower in Ccr2-/- EAO testes. Notably, fibronectin+ TMs were also present in biopsies from patients with impaired spermatogenesis and fibrotic alterations. Overexpression of the activin A antagonist follistatin reduced tissue damage and collagen I+ TM accumulation in WT EAO testes, while treating macrophages with activin A in vitro increased the expression of Ccr2, Fn1, Cxcr4, and Mmp2 and enhanced migration along a CCL2 gradient; these effects were abolished by follistatin. Taken together, our data indicate that CCR2 and activin A promote fibrosis during testicular inflammation by regulating macrophage function. Inhibition of CCR2 or activin A protects against damage progression, offering a promising avenue for therapeutic intervention.

A single-cell atlas of the cycling murine ovary

The estrous cycle is regulated by rhythmic endocrine interactions of the nervous and reproductive systems, which coordinate the hormonal and ovulatory functions of the ovary. Folliculogenesis and follicle progression require the orchestrated response of a variety of cell types to allow the maturation of the follicle and its sequela, ovulation, corpus luteum formation, and ovulatory wound repair. Little is known about the cell state dynamics of the ovary during the estrous cycle and the paracrine factors that help coordinate this process. Herein, we used single-cell RNA sequencing to evaluate the transcriptome of >34,000 cells of the adult mouse ovary and describe the transcriptional changes that occur across the normal estrous cycle and other reproductive states to build a comprehensive dynamic atlas of murine ovarian cell types and states.

An Update on In Vitro Folliculogenesis: A New Technique for Post-Cancer Fertility

Introduction: Obtaining in vitro mature oocytes from ovarian tissue to preserve women’s fertility is still a challenge. At present, there is a therapeutic deadlock for girls and women who need emergency fertility preservation in case of a high risk of ovary invasion by malignant cells. In such a case, ovarian tissue cannot be engrafted; an alternative could be in vitro folliculogenesis. Methods: This review focuses on the progress of in vitro folliculogenesis in humans. PubMed and Embase databases were used to search for original English-language articles. Results: The first phase of in vitro folliculogenesis is carried out in the original ovarian tissue. The addition of one (or more) initiation activator(s) is not essential but allows better yields and the use of a 3D culture system at this stage provides no added value. The second stage requires a mechanical and/or enzymatic isolation of the secondary follicles. The use of an activator and/or a 3D culture system is then necessary. Conclusion: The current results are promising but there is still a long way to go. Obtaining live births in large animals is an essential step in validating this in vitro folliculogenesis technique.

Sex specificity of pancreatic cancer cachexia phenotypes, mechanisms, and treatment in mice and humans: role of Activin

BACKGROUND

Cachexia is frequent, deadly, and untreatable for patients with pancreatic ductal adenocarcinoma (PDAC). The reproductive hormone and cytokine Activin is a mediator of PDAC cachexia, and Activin receptor targeting was clinically tested for cancer cachexia therapy. However, sex-specific manifestations and mechanisms are poorly understood, constraining development of effective treatments.

METHODS

Cachexia phenotypes, muscle gene/protein expression, and effects of the Activin blocker ACVR2B/Fc were assessed in LSL-KrasG12D/+ , LSL-Trp53R172H/+ , and Pdx-1-Cre (KPC) mice with autochthonic PDAC. Effects of PDAC and sex hormones were modelled by treating C2C12 myotubes with KPC-cell conditioned medium (CM) and estradiol. Muscle gene expression by RNAseq and change in muscle from serial CT scans were measured in patients with PDAC.

RESULTS

Despite equivalent tumour latency (median 17 weeks) and mortality (24.5 weeks), male KPC mice showed earlier and more severe cachexia than females. In early PDAC, male gastrocnemius, quadriceps, and tibialis anterior muscles were reduced (-21.7%, -18.9%, and -20.8%, respectively, all P < 0.001), with only gastrocnemius reduced in females (-16%, P < 0.01). Sex differences disappeared in late PDAC. Plasma Activin A was similarly elevated between sexes throughout, while oestrogen and testosterone levels suggested a virilizing effect of PDAC in females. Estradiol partially protected myotubes from KPC-CM induced atrophy and promoted expression of the potential Activin inhibitor Fstl1. Early-stage female mice showed greater muscle expression of Activin inhibitors Fst, Fstl1, and Fstl3; this sex difference disappeared by late-stage PDAC. ACVR2B/Fc initiated in early PDAC preserved muscle and fat only in male KPC mice, with increases of 41.2%, 52.6%, 39.3%, and 348.8%, respectively, in gastrocnemius, quadriceps, tibialis, and fat pad weights vs. vehicle controls, without effect on tumour. No protection was observed in females. At protein and RNA levels, pro-atrophy pathways were induced more strongly in early-stage males, with sex differences less evident in late-stage disease. As with mass, ACVR2B/Fc blunted atrophy-associated pathways only in males. In patients with resectable PDAC, muscle expression of Activin inhibitors FSTL1, FSLT3, and WFIKKN2/GASP2 were higher in women than men. Overall, among 124 patients on first-line gemcitabine/nab-paclitaxel for PDAC, only men displayed muscle loss (P < 0.001); average muscle wasting in men was greater (-6.63 ± 10.70% vs. -1.62 ± 12.00% mean ± SD, P = 0.038) and more rapid (-0.0098 ± 0.0742%/day vs. -0.0466 ± 0.1066%/day, P = 0.017) than in women.

CONCLUSIONS

Pancreatic ductal adenocarcinoma cachexia displays sex-specific phenotypes in mice and humans, with Activin a preferential driver of muscle wasting in males. Sex is a major modulator of cachexia mechanisms. Consideration of sexual dimorphism is essential for discovery and development of effective treatments.

Organotypic Culture of Testicular Tissue from Infant Boys with Cryptorchidism

Organotypic culture of human fetal testis has achieved fertilization-competent spermatids followed by blastocysts development. This study focuses on whether the organotypic culture of testicular tissue from infant boys with cryptorchidism could support the development of spermatogonia and somatic cells. Frozen-thawed tissues were cultured in two different media, with or without retinoic acid (RA), for 60 days and evaluated by tissue morphology and immunostaining using germ and somatic cell markers. During the 60-day culture, spermatocytes stained by boule-like RNA-binding protein (BOLL) were induced in biopsies cultured with RA. Increased AR expression (p < 0.001) and decreased AMH expression (p < 0.001) in Sertoli cells indicated advancement of Sertoli cell maturity. An increased number of SOX9-positive Sertoli cells (p < 0.05) was observed, while the percentage of tubules with spermatogonia was reduced (p < 0.001). More tubules with alpha-smooth muscle actin (ACTA, peritubular myoid cells (PTMCs) marker) were observed in an RA-absent medium (p = 0.02). CYP17A1/STAR-positive Leydig cells demonstrated sustained steroidogenic function. Our culture conditions support the initiation of spermatocytes and enhanced maturation of Sertoli cells and PTMCs within infant testicular tissues. This study may be a basis for future studies focusing on maintaining and increasing the number of spermatogonia and identifying different factors and hormones, further advancing in vitro spermatogenesis.

Ovarian expression of follicle stimulating hormone and activin receptors genes in a prenatally-androgenized rat model of polycystic ovary syndrome in adulthood

BACKGROUND

The expression of genes involved in basic pathways, such as folliculogenesis and steroidogenesis may be affected following prenatal androgen exposure. Besides, exposure to androgens during prenatal life plays a central role in developing polycystic ovary syndrome (PCOS) in females in later life. In the present study, we aimed to examine the expression of the follicle stimulating hormone receptor (FSHR) and activin receptor (actR) genes in ovarian granulosa cells (GCs) of a prenatally-androgenized rat model of PCOS in adulthood.

METHODS AND RESULTS

In the adult rat model of PCOS and their controls (n = 8 in each group), different phases of the estrous cycle were determined by vaginal smear. Total RNA was extracted from the ovarian GCs using the TRIzol protocol, a reverse transcription kit was used for complementary DNA (cDNA) synthesis, and the expression of FSHR and actR genes was measured by SYBR-Green Real-Time PCR. GraphPad Prism was used for statistical analysis of data, and the t-Student's test was used to compare the results between the two groups. PCOS rats had longer and irregular estrous cycles compared to controls. The expression of FSHR and actR genes were significantly decreased in the rat model of PCOS compared to control rats. In PCOS rats, genes expression ratios for FSHR and actR were 0.91 ± 0.11 times (P = 0.008) and 0.42 ± 0.13 times (P = 0.048) less than controls, respectively.

CONCLUSION

Reduced expression of the FSHR and actR genes in ovarian GCs may be one of the mechanisms mediating PCOS-related disorders, especially abnormal ovarian folliculogenesis and ovulation dysfunction, following exposure to androgens during fetal life.

Mammalian cumulus-oocyte complex communication: a dialog through long and short distance messaging

Communications are crucial to ovarian follicle development and to ovulation, and while both folliculogenesis and oogenesis are distinct processes, they share highly interdependent signaling pathways. Signals from distant organs such as the brain must be processed and compartments within the follicle have to be synchronized. The hypothalamic–pituitary–gonadal (HPG) axis relies on long-distance signalling analogous to wireless communication by which data is disseminated in the environment and cells equipped with the appropriate receptors receive and interpret the messages. In contrast, direct cell-to-cell transfer of molecules is a very targeted, short distance messaging system. Numerous signalling pathways have been identified and proven to be essential for the production of a developmentally competent egg. The development of the cumulus-oocyte complex relies largely on short distance communications or direct transfer type via extensions of corona radiata cells through the zona pellucida. The type of information transmitted through these transzonal projections is still largely uncharacterized. This review provides an overview of current understanding of the mechanisms by which the gamete receives and transmits information within the follicle. Moreover, it highlights the fact that in addition to the well-known systemic long-distance based communications from the HPG axis, these mechanisms acting more locally should also be considered as important targets for controlling/optimizing oocyte quality.

Cardiometabolic biomarkers in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. Apart from the reproductive problems, PCOS is also associated with metabolic disturbances, and therefore, it also affects adolescents and postmenopausal women with PCOS as well as their offspring and other first-degree relatives. Adolescents with PCOS show unfavorable cardiometabolic biomarkers more often than controls, such as overweight/obesity and hyperandrogenism, and studies also suggest an unfavorable lipid profile. During reproductive age, women with PCOS develop additional cardiometabolic biomarkers, such as hypertension, insulin resistance, and metabolic syndrome. Growing evidence also supports the important role of inflammatory cytokines in cardiovascular health in these women. During menopausal transition, some PCOS characteristics ameliorate, whereas other biomarkers increase, such as body mass index, insulin resistance, type 2 diabetes, and hypertension. Offspring of women with PCOS have a lower birth weight and a higher body mass index later in life than controls. In addition, fathers, mothers, and siblings of women with PCOS show unfavorable cardiometabolic biomarkers. Therefore, cardiovascular screening and follow-up of women with PCOS and their offspring and siblings are of utmost importance.

Activin a promotes hyaluronan production and upregulates versican expression in human granulosa cells via the ALK4-SMAD2/3-SMAD4 signaling pathway

Hyaluronan is a structural component of the expanded cumulus matrix, and hyaluronan synthase 2 (HAS2) is the major enzyme for the synthesis of hyaluronan in humans. Versican cross-links the hyaluronan-rich matrix to cumulus cells and is critical for successful ovulation. Activin A is a critical intrafollicular regulator of ovarian function. Although activin A has been shown to promote cumulus matrix expansion in mice, the functional role of activin A in the regulation of cumulus expansion in the human ovary remains to be elucidated. Using primary and immortalized human granulosa-lutein (hGL) cells as study models, we provide the first data showing that activin A increased the production of hyaluronan by upregulating the expression of HAS2 in these cells. Additionally, activin A also promoted the expression of the hyaluronan-binding protein versican. Moreover, using inhibitor- and siRNA-mediated inhibition approaches, we found that these stimulatory effects of activin A are most likely mediated through the type I receptor ALK4-mediated SMAD2/SMAD3-SMAD4 signaling pathway. Notably, the ChIP analyses demonstrated that SMAD4 could bind to human HAS2 and VERSICAN promoters. The results obtained from this in vitro study suggest that locally produced activin A plays a functional role in the regulation of hyaluronan production and stabilization in hGL cells.

Inhibin Inactivation in Female Mice Leads to Elevated FSH Levels, Ovarian Overstimulation, and Pregnancy Loss

Inhibins are members of the transforming growth factor-β family, composed of a common α-subunit disulfide-linked to 1 of 2 β-subunits (βA in inhibin A or βB in inhibin B). Gonadal-derived inhibin A and B act in an endocrine manner to suppress the synthesis of follicle-stimulating hormone (FSH) by pituitary gonadotrope cells. Roles for inhibins beyond the pituitary, however, have proven difficult to delineate because deletion of the inhibin α-subunit gene (Inha) results in unconstrained expression of activin A and activin B (homodimers of inhibin β-subunits), which contribute to gonadal tumorigenesis and lethal cachectic wasting. Here, we generated mice with a single point mutation (Arg233Ala) in Inha that prevents proteolytic processing and the formation of bioactive inhibin. In vitro, this mutation blocked inhibin maturation and bioactivity, without perturbing activin production. Serum FSH levels were elevated 2- to 3-fold in InhaR233A/R233A mice due to the loss of negative feedback from inhibins, but no pathological increase in circulating activins was observed. While inactivation of inhibin A and B had no discernible effect on male reproduction, female InhaR233A/R233A mice had increased FSH-dependent follicle development and enhanced natural ovulation rates. Nevertheless, inhibin inactivation resulted in significant embryo-fetal resorptions and severe subfertility and was associated with disrupted maternal ovarian function. Intriguingly, heterozygous Inha+/R233A females had significantly enhanced fecundity, relative to wild-type littermates. These studies have revealed novel effects of inhibins in the establishment and maintenance of pregnancy and demonstrated that partial inactivation of inhibin A/B is an attractive approach for enhancing female fertility.

Diabetes as a potential compounding factor in COVID-19-mediated male subfertility

Recent work indicates that male fertility is compromised by SARS-CoV-2 infection. Direct effects derive from the presence of viral entry receptors (ACE2 and/or CD147) on the surface of testicular cells, such as spermatocytes, Sertoli cells, and Leydig cells. Indirect effects on testis and concentrations of male reproductive hormones derive from (1) virus-stimulated inflammation; (2) viral-induced diabetes, and (3) an interaction between diabetes and inflammation that exacerbates the deleterious effect of each perturbation. Reproductive hormones affected include testosterone, luteinizing hormone, and follicle-stimulating hormone. Reduction of male fertility is also observed with other viral infections, but the global pandemic of COVID-19 makes demographic and public health implications of reduced male fertility of major concern, especially if it occurs in the absence of serious symptoms that would otherwise encourage vaccination. Clinical documentation of COVID-19-associated male subfertility is now warranted to obtain quantitative relationships between infection severity and subfertility; mechanistic studies using animal models may reveal ways to mitigate the problem. In the meantime, the possibility of subfertility due to COVID-19 should enter considerations of vaccine hesitancy by reproductive-age males.

Activin A attenuates apoptosis of granulosa cells in atretic follicles through ERβ-induced autophagy

It is well known that about 99% of ovarian follicles in mammals suffer from a degenerative process known as atresia, which is a huge waste of genetic resource in female animals. Studies have shown that activin A (ACT-A) is located in ovarian granulosa cells and has different effects in granulosa cell depending on species. Although granulosa cells play a critical role during follicular atresia, the mechanism of action of ACT-A in bovine ovarian granulosa cells (BGC) is poorly understood. In this study, we firstly determined the apoptosis of BGCs isolated from growth follicles and atretic follicles, respectively. Then, BGC isolated from atretic follicles were used as a model to elucidate the role of ACT-A in cattle ovary. The results showed that apoptosis occurred in both growing follicles and atretic follicles, and the percentage of apoptotic cells in atretic follicles was higher than that in growing follicles. The current results indicated that ACT-A can attenuate apoptosis of BGC through maintaining the function of BGC in atretic follicles. Increased ERβ induced by ACT-A promoted BGC autophagy but had no effect on apoptosis. In summary, this study suggests that ACT-A attenuates BGC apoptosis in atretic follicles by ERβ-mediated autophagy signaling.

Mitochondrial regulation during male germ cell development

Mitochondria tailor their morphology to execute their specialized functions in different cell types and/or different environments. During spermatogenesis, mitochondria undergo continuous morphological and distributional changes with germ cell development. Deficiencies in these processes lead to mitochondrial dysfunction and abnormal spermatogenesis, thereby causing male infertility. In recent years, mitochondria have attracted considerable attention because of their unique role in the regulation of piRNA biogenesis in male germ cells. In this review, we describe the varied characters of mitochondria and focus on key mitochondrial factors that play pivotal roles in the regulation of spermatogenesis, from primordial germ cells to spermatozoa, especially concerning metabolic shift, stemness and reprogramming, mitochondrial transformation and rearrangement, and mitochondrial defects in human sperm. Further, we discuss the molecular mechanisms underlying these processes.

Identification of a novel immune signature for optimizing prognosis and treatment prediction in colorectal cancer

BACKGROUND

Globally, colorectal cancer (CRC) is one of the most lethal malignant diseases. However, the currently approved therapeutic options for CRC failed to acquire satisfactory treatment efficacy. Tailoring therapeutic strategies for CRC individuals can provide new insights into personalized prediction approaches and thus maximize clinical benefits.

METHODS

In this study, a multi-step process was used to construct an immune-related genes (IRGs) based signature leveraging the expression profiles and clinical characteristics of CRC from the Gene Expression Omnibus (GEO) database and the Cancer Genome Atlas (TCGA) database. An integrated immunogenomic analysis was performed to determine the association between IRGs with prognostic significance and cancer genotypes in the tumor immune microenvironment (TIME). Moreover, we performed a comprehensive in silico therapeutics screening to identify agents with subclass-specific efficacy.

RESULTS

The established signature was shown to be a promising biomarker for evaluating clinical outcomes in CRC. The immune risk score as calculated by this classifier was significantly correlated with over-riding malignant phenotypes and immunophenotypes. Further analyses demonstrated that CRCs with low immune risk scores achieved better therapeutic benefits from immunotherapy, while AZD4547, Cytochalasin B and S-crizotinib might have potential therapeutic implications in the immune risk score-high CRCs.

CONCLUSIONS

Overall, this IRGs-based signature not only afforded a useful tool for determining the prognosis and evaluating the TIME features of CRCs, but also shed new light on tailoring CRCs with precise treatment.

Activin B, a new player in kidney fibrosis?†

Interest has been growing in the role of activin A in both acute and chronic kidney disease. The role of other activins, however, remains relatively unexplored. In a recent issue of the Journal of Pathology, an elegant study by Sun et al. identified upregulation of INHBB, the subunit of activin B, in three different models of kidney fibrosis, as well as in human kidneys with fibrosis. This increase was shown to be mediated by upregulation of the transcription factor Sox9. Using overexpression and inhibition strategies, the importance of INHBB to kidney interstitial fibroblast activation and kidney fibrosis was clearly shown. Importantly, INHBB and Sox9 are not appreciably expressed in normal tissue. These studies lay important groundwork for the further investigation of activin B targeting as a potential therapeutic approach to attenuate kidney fibrosis. This article is protected by copyright. All rights reserved.

INHBA transfection regulates proliferation, apoptosis and hormone synthesis in sheep granulosa cells

Inhibin subunit beta A (INHBA) participates in the synthesis of inhibin A, activin A and activin AB. Here we investigated the effect and molecular mechanism of INHBA on proliferation, apoptosis and hormone synthesis in sheep granulosa cells (GCs) using in vitro transfection. We first noticed that INHBA expression increased with follicle diameter and was widely distributed in ovarian tissue. The proliferation rate of GCs was significantly increased and decreased with overexpression and silence of INHBA, respectively, compared with the negative controls. INHBA transfection affected GC proliferation and apoptosis, regulating the expression of many cell cycle-related and apoptosis-related genes. INHBA overexpression significantly decreased activin and estradiol secretion while increasing inhibin and progesterone secretion. The expression of follicle-stimulating hormone beta subunit was significantly decreased and increased with INHBA overexpression and knockdown, respectively. Notably, silence of INHBA inhibited the expression of many transforming growth factor beta-related genes. Overall, the functional molecule of INHBA gene may be associated with follicular development via regulating proliferation, apoptosis and folliculogenesis-related hormone secretion of sheep GCs. In addition, our findings may contribute to a better understanding of the law of follicular development and thus improve the reproductive performance of female animals.

CellCall: integrating paired ligand-receptor and transcription factor activities for cell-cell communication

With the dramatic development of single-cell RNA sequencing (scRNA-seq) technologies, the systematic decoding of cell-cell communication has received great research interest. To date, several in-silico methods have been developed, but most of them lack the ability to predict the communication pathways connecting the insides and outsides of cells. Here, we developed CellCall, a toolkit to infer inter- and intracellular communication pathways by integrating paired ligand-receptor and transcription factor (TF) activity. Moreover, CellCall uses an embedded pathway activity analysis method to identify the significantly activated pathways involved in intercellular crosstalk between certain cell types. Additionally, CellCall offers a rich suite of visualization options (Circos plot, Sankey plot, bubble plot, ridge plot, etc.) to present the analysis results. Case studies on scRNA-seq datasets of human testicular cells and the tumor immune microenvironment demonstrated the reliable and unique functionality of CellCall in intercellular communication analysis and internal TF activity exploration, which were further validated experimentally. Comparative analysis of CellCall and other tools indicated that CellCall was more accurate and offered more functions. In summary, CellCall provides a sophisticated and practical tool allowing researchers to decipher intercellular communication and related internal regulatory signals based on scRNA-seq data. CellCall is freely available at https://github.com/ShellyCoder/cellcall.

Embryonic stem cells are devoid of macropinocytosis, a trafficking pathway for activin A in differentiated cells

Ligand-receptor complexes formed at the plasma membrane are internalised via various endocytic pathways that influence the ultimate signalling output by regulating the selection of interaction partners by the complex along the trafficking route. We report that, in differentiated cells, activin A-receptor complexes are internalised via clathrin-mediated endocytosis (CME) and macropinocytosis (MP), whereas in human embryonic stem cells (hESCs) internalisation occurs via CME. We further show that hESCs are devoid of MP, which becomes functional upon differentiation towards endothelial cells through mesoderm mediators. Our results reveal, for the first time, that MP is an internalisation route for activin A in differentiated cells, and that MP is not active in hESCs and is induced as cells differentiate.

Serum calponin 2 is a novel biomarker of tubal ectopic pregnancy

OBJECTIVE

To evaluate serum protein calponin 2 (CNN2) as a candidate biomarker for tubal ectopic pregnancy (EP).

DESIGN

Retrospective study.

SETTING

Single University affiliated tertiary hospital.

PATIENT(S)

Serum samples were obtained from 84 patients with EP, 39 with viable intrauterine pregnancy (vIUP), and 42 with miscarriage. Moreover, 10 fallopian tube and corresponding villous tissue samples from patients with EP, 6 villous tissue samples from patients with vIUP, and 10 villous tissue samples from patients with miscarriage were collected.

INTERVENTION(S)

Serum CNN2 concentrations were measured using enzyme-linked immunosorbent assay; CNN2 expression in tissues was evaluated via immunohistochemistry and quantitative real-time polymerase chain reaction analysis.

MAIN OUTCOME MEASURE(S)

The diagnostic performance of serum CNN2 to discriminate an EP from vIUP and miscarriage.

RESULT(S)

CNN2 was highly expressed in villous stromal cells isolated from patients with EP, and CNN2 messenger ribonucleic acid expression was upregulated in villous tissues from women with EP compared with that in women with vIUPs and miscarriages. Serum CNN2 concentration was higher in women with EP than that in women with vIUP and miscarriage. The serum CNN2 predicted EP from vIUP and miscarriage with areas under the curve (AUCs) of 0.931 (95% confidence interval: 0.889-0.975). For discriminating EP from miscarriage only, the AUC was 0.906 (95% confidence interval: 0.835-0.977). In contrast, the AUCs for serum human chorionic gonadotropin were 0.809 and 0.637, respectively.

CONCLUSION(S)

Our data highlight the possibility of serum CNN2 as a single biomarker for the diagnosis of EP.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR 1900020483.

Experimental Cryptorchidism Causes Chronic Inflammation and a Progressive Decline in Sertoli Cell and Leydig Cell Function in the Adult Rat Testis

Cryptorchidism causes spermatogenic failure and reduced serum androgen levels, as well as testicular oedema and fibrosis, which are hallmarks of inflammation. However, the role of inflammation and the effects of cryptorchidism on Sertoli cell and Leydig cell function at the molecular level remain ill-defined. Bilateral cryptorchidism was surgically induced in adult rats for 7 and 14 weeks. Testis weights decreased to 40% of normal within 7 weeks, due to loss of all developing spermatogenic cells except spermatogonia, but did not decrease further at 14 weeks. Serum FSH and LH were increased at both time points, consistent with a loss of feedback by inhibin and testosterone. This damage was accompanied by progressive accumulation of interstitial fluid and peritubular fibrosis, and a progressive decline of several critical Sertoli cell genes (Sox9, Inha (inhbin α-subunit), Cldn11 (claudin 11), Gja1 (connexin 43), and Il1a (interleukin-1α)) and the Leydig cell steroidogenic enzymes, Cyp11a1, Hsd3b1, and Hs17b3. Activin B and the activin-binding protein, follistatin, also declined, but the intratesticular concentration of activin A, which is a regulator of inflammatory responses, was largely unaffected at either time point. Expression of genes involved in inflammation (Tnf, Il10, Il1b, Mcp1) and fibrosis (Acta2, Col1a1) were considerably elevated at both time points. These data indicate that induction of experimental cryptorchidism, which causes complete failure of spermatogenesis in the adult rat, also induces chronic testicular inflammation, manifesting in oedema and fibrosis, and a progressive decline of Sertoli and Leydig cell gene expression and function.

Different phenotypes and chondrogenic responses of human menstrual blood and bone marrow mesenchymal stem cells to activin A and TGF-β3

BACKGROUND

Due to its low capacity for self-repair, articular cartilage is highly susceptible to damage and deterioration, which leads to the development of degenerative joint diseases such as osteoarthritis (OA). Menstrual blood-derived mesenchymal stem/stromal cells (MenSCs) are much less characterized, as compared to bone marrow mesenchymal stem/stromal cells (BMMSCs). However, MenSCs seem an attractive alternative to classical BMMSCs due to ease of access and broader differentiation capacity. The aim of this study was to evaluate chondrogenic differentiation potential of MenSCs and BMMSCs stimulated with transforming growth factor β (TGF-β3) and activin A.

METHODS

MenSCs (n = 6) and BMMSCs (n = 5) were isolated from different healthy donors. Expression of cell surface markers CD90, CD73, CD105, CD44, CD45, CD14, CD36, CD55, CD54, CD63, CD106, CD34, CD10, and Notch1 was analyzed by flow cytometry. Cell proliferation capacity was determined using CCK-8 proliferation kit and cell migration ability was evaluated by scratch assay. Adipogenic differentiation capacity was evaluated according to Oil-Red staining and osteogenic differentiation according to Alizarin Red staining. Chondrogenic differentiation (activin A and TGF-β3 stimulation) was investigated in vitro and in vivo (subcutaneous scaffolds in nude BALB/c mice) by expression of chondrogenic genes (collagen type II, aggrecan), GAG assay and histologically. Activin A protein production was evaluated by ELISA during chondrogenic differentiation in monolayer culture.

RESULTS

MenSCs exhibited a higher proliferation rate, as compared to BMMSCs, and a different expression profile of several cell surface markers. Activin A stimulated collagen type II gene expression and glycosaminoglycan synthesis in TGF-β3 treated MenSCs but not in BMMSCs, both in vitro and in vivo, although the effects of TGF-β3 alone were more pronounced in BMMSCs in vitro.

CONCLUSION

These data suggest that activin A exerts differential effects on the induction of chondrogenic differentiation in MenSCs vs. BMMSCs, which implies that different mechanisms of chondrogenic regulation are activated in these cells. Following further optimization of differentiation protocols and the choice of growth factors, potentially including activin A, MenSCs may turn out to be a promising population of stem cells for the development of cell-based therapies with the capacity to stimulate cartilage repair and regeneration in OA and related osteoarticular disorders.

ATF3 deficiency impairs the proliferative-secretory phase transition and decidualization in RIF patients

Decidualization is a complex process involving cellular proliferation and differentiation of the endometrial stroma and is required to establish and support pregnancy. Dysregulated decidualization has been reported to be a critical cause of recurrent implantation failure (RIF). In this study, we found that Activating transcription factor 3 (ATF3) expression was significantly downregulated in the endometrium of RIF patients. Knockdown of ATF3 in human endometrium stromal cells (hESCs) hampers decidualization, while overexpression could trigger the expression of decidual marker genes, and ameliorate the decidualization of hESCs from RIF patients. Mechanistically, ATF3 promotes decidualization by upregulating FOXO1 via suppressing miR-135b expression. In addition, the endometrium of RIF patients was hyperproliferative, while overexpression of ATF3 inhibited the proliferation of hESCs through CDKN1A. These data demonstrate the critical roles of endometrial ATF3 in regulating decidualization and proliferation, and dysregulation of ATF3 in the endometrium may be a novel cause of RIF and therefore represent a potential therapeutic target for RIF.