The discovery of kisspeptin as a critical central regulatory factor of GnRH release has given people a novel understanding of the neuroendocrine regulation in human reproduction. Kisspeptin activates the signaling pathway by binding to its receptor kisspeptin receptor (KISS1R) to promote GnRH secretion, thereby regulating the hypothalamic-pituitary-gonadal axis (HPG) axis. Recent studies have shown that kisspeptin neurons located in arcuate nucleus (ARC) co-express neurokinin B (NKB) and dynorphin (Dyn). Such neurons are called KNDy neurons. KNDy neurons participate in the positive and negative feedback of estrogen to GnRH secretion. In addition, kisspeptin is a key factor in the initiation of puberty, and also regulates the processes of female follicle development, oocyte maturation, and ovulation through the HPG axis. In male reproduction, kisspeptin also plays an important role, getting involved in the regulation of Leydig cells, spermatogenesis, sperm functions and reproductive behaviors. Mutations in the KISS1 gene or disorders of the kisspeptin/KISS1R system may lead to clinical symptoms such as idiopathic hypogonadotropic hypogonadism (iHH), central precocious puberty (CPP) and female infertility. Understanding the influence of kisspeptin on the reproductive axis and related mechanisms will help the future application of kisspeptin in disease diagnosis and treatment. In this review, we critically appraise the role of kisspeptin in the HPG axis, including its signaling pathways, negative and positive feedback mechanisms, and its control on female and male reproduction.

The mononuclear phagocytic system (MPS) is the primary innate immune cell group in male reproductive tissues, maintaining the balance of pro-inflammatory and immune tolerance. This article aims to outline the role of mononuclear macrophages in the immune balance of the testes and epididymis, and to understand the inner immune regulation mechanism. A review of pertinent publications was performed using the PubMed and Google Scholar databases on all articles published prior to January 2021. Search terms were based on the following keywords: ‘MPS’, ‘mononuclear phagocytes’, ‘testes’, ‘epididymis’, ‘macrophage’, ‘Mφ’, ‘dendritic cell’, ‘DC’, ‘TLR’, ‘immune’, ‘inflammation’, and ‘polarization’. Additionally, reference lists of primary and review articles were reviewed for other publications of relevance. This review concluded that MPS exhibits a precise balance in the male reproductive system. In the testes, MPS cells are mainly suppressed subtypes (M2 and cDC2) under physiological conditions, which maintain the local immune tolerance. Under pathological conditions, MPS cells will transform into M1 and cDC1, producing various cytokines, and will activate T cell specific immunity as defense to foreign pathogens or self-antigens. In the epididymis, MPS cells vary in the different segments, which express immune tolerance in the caput and pro-inflammatory condition in the cauda. Collectively, MPS is the control point for maintaining the immune tolerance of the testes and epididymis as well as for eliminating pathogens.

Melanoma, one of the most lethal cancers, demands urgent and effective treatment strategies. However, a successful therapeutic approach requires a precise understanding of the mechanisms underlying melanoma initiation and progression. This review provides an overview of melanoma pathogenesis, identifies current pathogenic factors contributing to mortality, and explores targeted therapy and checkpoint inhibitor therapy. Furthermore, we examine melanoma classification and corresponding therapies, along with advancements in various cell death mechanisms for melanoma treatment. We also discuss the current treatment status along with some drawbacks encountered during research stages such as resistance and metastasis.

C-type natriuretic peptide (CNP) is highly expressed in male reproductive tissues, such as the epididymis. The aim of this study is to explore the role of CNP in the maturation of rat epididymal spermatozoa. First, the expression levels of CNP and its specific natriuretic peptide receptor-B (NPR-B) were detected in various tissues of rats and epididymis at different stages after birth. Then a castrated rat model was established to analyze the relationship between testosterone and CNP/NPR-B expression in the epididymis. Finally, CNP and different inhibitors (NPR-B inhibitors, cGMP inhibitors) were used to incubate epididymal sperm in vitro to examine sperm mobility and expression of sperm maturation-related factors. The results showed CNP/NPR-B mRNAs were expressed in all tissues of rats, but were extremely highly expressed in male genital ducts (seminal vesicle, prostate and epididymis). The expression of CNP/NPR-B in epididymis was the highest at birth and the fifth week after birth. In the epididymis, CNP/NPR-B were highly expressed in the caput and located in the epididymal epithelial cells. After castration, the expression of CNP/NPR-B decreased sharply and was restored quickly after testosterone supplementation. In vitro, CNP could significantly promote the acquisition of epididymal sperm motility through the NPR-B/cGMP pathway and induce the expression of sperm maturation-related factors (such as Bin1b, Catsper 1, Dnah17, Fertilin). This study shows that CNP plays a role in epididymal sperm maturation. The mechanism of CNP is to promote the acquisition of epididymal sperm fluidity through the NPR-B/cGMP signaling pathway and also to regulate sperm maturation-related genes. Moreover, the expression of CNP/NPR-B was regulated by testosterone.

Introduction. Urokinase plasminogen activator (uPA) is a serine protease and it also demonstrates proinflammatory properties. We thus hypothesized that uPA is involved in immunity of Sertoli cells in the rat testis. Materials and methods. The uPA gene(PLAU) promoter was cloned by RT-PCR and the transcriptional activation of core domain was screened by using Dual-Luciferase Reporter Assay System. The Sertoli cells were harvested from 20-day-old Sprague-Dawley male rats and total RNA was isolated. The uPA mRNA levels and MyD88 pathway were tested by qPCR. Results. We successfully cloned the 1517-bp rat uPA gene and screened the core domain (-455/+40) in five different fragments of uPA promoter. The uPA expression and uPA promoter activity were upregulated in lipopolysaccharide (LPS)-stimulated Sertoli cells. Furthermore, the uPA expression was regulated through the MyD88-independent pathway by interdicting IRF3 and interferon β. Conclusion. uPA expression is likely induced by LPS through the core promoter domain of uPA. This finding implied that uPA played a role in the immune function of Sertoli cells in rat testis, which might provide the development of new treatments for male infertility. Introduction. Urokinase plasminogen activator (uPA) is a serine protease and it also demonstrates proinflammatory properties. We thus hypothesized that uPA is involved in immunity of Sertoli cells in the rat testis. Materials and methods. The uPA gene(PLAU) promoter was cloned by RT-PCR and the transcriptional activation of core domain was screened by using Dual-Luciferase Reporter Assay System. The Sertoli cells were harvested from 20-day-old Sprague-Dawley male rats and total RNA was isolated. The uPA mRNA levels and MyD88 pathway were tested by qPCR. Results. We successfully cloned the 1517-bp rat uPA gene and screened the core domain (-455/+40) in five different fragments of uPA promoter. The uPA expression and uPA promoter activity were upregulated in lipopolysaccharide (LPS)-stimulated Sertoli cells. Furthermore, the uPA expression was regulated through the MyD88-independent pathway by interdicting IRF3 and interferon β. Conclusion. uPA expression is likely induced by LPS through the core promoter domain of uPA. This finding implied that uPA played a role in the immune function of Sertoli cells in rat testis, which might provide the development of new treatments for male infertility.