Predomination of IL-17-producing tryptase-positive/chymase-positive mast cells in azoospermic chronic testicular inflammation

Integrative bioinformatics analysis to identify novel biomarkers associated with non-obstructive azoospermia

Aim

This study aimed to identify autophagy-related genes (ARGs) associated with non-obstructive azoospermia and explore the underlying molecular mechanisms.

Methods

Two datasets associated with azoospermia were downloaded from the Gene Expression Omnibus database, and ARGs were obtained from the Human Autophagy-dedicated Database. Autophagy-related differentially expressed genes were identified in the azoospermia and control groups. These genes were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, protein–protein interaction (PPI) network, and functional similarity analyses. After identifying the hub genes, immune infiltration and hub gene–RNA-binding protein (RBP)–transcription factor (TF)–miRNA–drug interactions were analyzed.

Results

A total 46 differentially expressed ARGs were identified between the azoospermia and control groups. These genes were enriched in autophagy-associated functions and pathways. Eight hub genes were selected from the PPI network. Functional similarity analysis revealed that HSPA5 may play a key role in azoospermia. Immune cell infiltration analysis revealed that activated dendritic cells were significantly decreased in the azoospermia group compared to those in the control groups. Hub genes, especially ATG3, KIAA0652, MAPK1, and EGFR were strongly correlated with immune cell infiltration. Finally, a hub gene–miRNA–TF–RBP–drug network was constructed.

Conclusion

The eight hub genes, including EGFR, HSPA5, ATG3, KIAA0652, and MAPK1, may serve as biomarkers for the diagnosis and treatment of azoospermia. The study findings suggest potential targets and mechanisms for the occurrence and development of this disease.

IL-17+ Mast Cell/T Helper Cell Axis in the Early Stages of Acne

Acne is a multifactorial disease driven by physiological changes occurring during puberty in the pilosebaceous unit (PSU) that leads to sebum overproduction and a dysbiosis involving notably Cutibacterium acnes. These changes in the PSU microenvironment lead to a shift from a homeostatic to an inflammatory state. Indeed, immunohistochemical analyses have revealed that inflammation and lymphocyte infiltration can be detected even in the infraclinical acneic stages, highlighting the importance of the early stages of the disease. In this study, we utilized a robust multi-pronged approach that included flow cytometry, confocal microscopy, and bioinformatics to comprehensively characterize the evolution of the infiltrating and resident immune cell populations in acneic lesions, beginning in the early stages of their development. Using a discovery cohort of 15 patients, we demonstrated that the composition of immune cell infiltrate is highly dynamic in nature, with the relative abundance of different cell types changing significantly as a function of clinical lesion stage. Within the stages examined, we identified a large population of CD69⁺ CD4⁺ T cells, several populations of activated antigen presenting cells, and activated mast cells producing IL-17. IL-17⁺ mast cells were preferentially located in CD4⁺ T cell rich areas and we showed that activated CD4⁺ T cells license mast cells to produce IL-17. Our study reveals that mast cells are the main IL-17 producers in the early stage of acne, underlying the importance of targeting the IL-17⁺ mast cell/T helper cell axis in therapeutic approaches.

Evaluation of immune status in testis and macrophage polarization associated with testicular damage in patients with nonobstructive azoospermia

OBJECTIVE

Immune cells residing in the testicular interstitial space form the immunological microenvironment of the testis. They are assumed to play a role in maintaining testicular homeostasis and immune privilege. However, the immune status and related cell polarization in patients with nonobstructive azoospermia (NOA) remains poorly characterized. System evaluation of the testis immunological microenvironment in NOA patients may help to reveal the mechanisms of idiopathic azoospermia.

STUDY DESIGN

The gene expression patterns of immune cells in normal human testes were systematically analyzed by single-cell RNA sequencing (scRNA-seq) and preliminarily verification by the human protein atlas (HPA) online database. The immune cell infiltration profiles and immune status of patients with NOA was analyzed by single-sample gene set enrichment analysis (ssGSEA) and gene set variation analysis (GSVA) based on four independent public microarray datasets (GSE45885, GSE45887, GSE9210, and GSE145467), obtained from Gene Expression Omnibus (GEO) online database. The relationship between immune cells and spermatogenesis score was further analyzed by Spearman correlation analysis. Finally, immunohistochemistry (IHC) staining was performed to identify the main immune cell types and their polarization status in patients with NOA.

RESULTS

Both scRNA-seq and HPA analysis showed that testicular macrophages represent the largest pool of immune cells in the normal testis, and also exhibit an attenuated inflammatory response by expressing high levels of tolerance proteins (CD163, IL-10, TGF-β, and VEGF) and reduced expression of TLR signaling pathway-related genes. Correlation analysis revealed that the testicular immune score and macrophages including M1 and M2 macrophages were significantly negatively correlated with spermatogenesis score in patients with NOA (GSE45885 and GSE45887). In addition, the number of M1 and M2 macrophages was significantly higher in patients with NOA (GSE9210 and GSE145467) than in normal testis. GSVA analysis indicated that the immunological microenvironment in NOA tissues was manifested by activated immune system and pro-inflammatory status. IHC staining results showed that the number of M1 and M2 macrophages was significantly higher in NOA tissues than in normal testis and negatively correlated with the Johnson score.

CONCLUSION

Testicular macrophage polarization may play a vital role in NOA development and is a promising potential therapeutic target.

Testicular steroid sulfatase overexpression is associated with Leydig cell dysfunction in primary spermatogenic failure

BACKGROUND

Decreased testosterone (T) to LH ratio and increased 17β-estradiol (E2) serum concentrations represent a common finding among patients with severe spermatogenic failure, suggesting a concurrent Leydig cell steroidogenic dysfunction. Aromatase overexpression has been associated with increased serum and intratesticular E2 in these patients. However, it is unknown whether the sulfatase pathway contributes to the increased availability of active estrogens in patients with primary spermatogenic failure.

OBJECTIVES

To assess estrogen sulfotransferase (SULT1E1) and steroid sulfatase (STS) mRNA abundance in testicular tissue of patients with Sertoli cell-only syndrome (SCOS) and normal tissues, its association with serum and intratesticular hormone levels, and to explore the mRNA and protein testicular localization of both enzymes.

MATERIALS AND METHODS

Testicular tissues of 23 subjects with SCOS (cases) and 22 patients with obstructive azoospermia and normal spermatogenesis (controls) were obtained after biopsy. SULT1E1 and STS transcripts accumulation was quantified by RT-qPCR. For mRNA and protein localization, we performed RT-qPCR in Leydig cell clusters and seminiferous tubules isolated by laser-capture microdissection and immunofluorescence in testicular tissues. Serum and intratesticular hormones were measured by immunoradiometric assays.

RESULTS

SULT1E1 mRNA accumulation was similar in both groups. The amount of STS mRNA was higher in cases (p = 0.007) and inversely correlated with T/LH ratio (r = -0.402; p = 0.02). Also, a near significant correlation was observed with intratesticular E2 (r = 0.329, p = 0.057), in agreement with higher intratesticular E2 in cases (p < 0.001). Strong STS immunoreaction was localized in the wall of small blood vessels but not in Leydig cells. Both SULT1E1 and STS mRNA abundance was similar in Leydig cell clusters and the tubular compartment, except for lower SUTL1E1 mRNA in the seminiferous tubules of SCOS patients (p = 0.001).

CONCLUSIONS

Our results suggest that an unbalance of the STS/SULT1E1 pathway contributes to the testicular hyperestrogenic microenvironment in patients with primary spermatogenic failure and Leydig cell dysfunction.

Significance of mast cells in spermatogenesis, implantation, pregnancy, and abortion: Cross talk and molecular mechanisms

Both subsets of MCs including MC_TC (tryptase-positive, chymase-positive) and MC_T (tryptase-positive, chymase-negative) are present in the testis and epididymis. Increased number of MCs, higher levels of MC-released tryptase in testis and seminal plasma of males with fertility problems, and promoting sperm motility in individuals with oligozoospermia after using MC blockers provide evidence that MCs may play a role in male infertility/subfertility disturbances. MC-released tryptase and histamine contribute to the fibrosis and may disrupt spermatogenesis. MCs not only influence the process of spermatogenesis but also have effects on the function of other testis-residing cells. MC-derived histamine may influence the steroidogenesis of Leydig cells by acting through H1R and H2R receptors. Additionally, the interaction between MC-released ATP and P2X receptors expressed on the peritubular cells may induce the production of the pro-inflammatory mediators by peritubular cells. Further investigations showed that MCs may be involved in the pathology of female infertility during implantation, pregnancy, and abortion. In the uterus, MC_T subtype is abundant in myometrium and adjacent basal layer while MC_TC subtype is distributed in all layers. MCs in response to hormones mainly estradiol and progesterone become activated and release a wide range of mediators including histamine, VEGF, proteases, and metalloproteinases (MMPs) that have a role in different stages of pregnancy. An increasing influx of MCs to the cervix during the pregnancy occurs that helps to the physiologic cervical ripening. While MMPs degrade the extracellular matrix (ECM), VEGF modulates neovascularization and histamine influences the embryo implantation. MC-derived histamine may have a positive effect during implantation due to its participation in tissue remodeling. MC proteases including tryptase and chymase activate the precursors of MMP2 and MMP9 to mediate ECM degradation during the physiologic menstrual cycle. There is a line of evidence that MCs have a role in abortion by releasing TNF-α.

Mouse Mast Cell Protease-4 Recruits Leukocytes in the Inflammatory Phase of Surgically Wounded Skin

Objective: Mouse mast cell protease-4 (mMCP-4, also known as chymase) has both pro- and anti-inflammatory roles depending on the disease model. However, its effects have not been studied in surgically wounded skin. Given the significant clinical applications of modulating the inflammatory response in wound healing, we examined the role of mMCP-4 and the effect of its inhibitor chymostatin on leukocyte and polymorphonuclear cell (PMN) recruitment in our skin model. Approach: Recruitment was assessed on day-1 postwounding of three groups of mice (n = 10 each): mMCP-4 null mice, wild-type (WT) mice treated with the mMCP-4 inhibitor chymostatin, and WT with no other intervention. Leukocytes were stained with CD-45 cell marker, and PMN cells were stained with chloroacetate esterase. Results: The WT mice had 27 ± 9 leukocytes per field compared with 11 ± 6 for the mMCP-4 nulls, a decrease of 60% (p = 0.03), whereas the chymostatin-injected group had a count comparable with the uninjected WT controls at 24 ± 9. The WT group had a PMN count of 96 ± 12 cells, compared with just 24 ± 8 in the mMCP-4 null group, a decrease of 75% (p = 0.001), whereas the chymostatin-treated group had 60 ± 18 cells, a decrease of 38% compared with the WT group (p = 0.03). Innovation: We showed that the inflammatory process can be influenced by impeding the arrival of PMNs into the surgically injured site using the mMCP-4 inhibitor chymostatin. Conclusion: Chymase contributes to the recruitment of white blood cells in surgically wounded skin.

High prevalence of urogenital infection/inflammation in patients with azoospermia does not impede surgical sperm retrieval

Considering infection/inflammation to be an important risk factor in male infertility, the aim of this study was to make a comprehensive evaluation of the prevalence of urogenital tract infection/inflammation and its potential impact on sperm retrieval in azoospermic patients. In this prospective study, 71 patients with azoospermia were subjected to an extensive andrological workup including comprehensive microbiological diagnostics (2-glass test, semen, testicular swab and testicular tissue analysis) and testicular biopsy/testicular sperm extraction (TESE). Medical history suggested urogenital tract infection/inflammation in 7% of patients, 11% harboured STIs, 14% showed significant bacteriospermia, 15% had seminal inflammation, 17% fulfilled the MAGI definition, and 27% had relevant pathogens. At the testicular level, 1 patient had a swab positive for bacteria, no viruses were detected, tissue specimens never indicated pathogens, whereas histopathology revealed focal immune cell infiltrates in 23% of samples. Testicular sperm retrieval rate was 100% in obstructive and 46% in nonobstructive azoospermia. None of the infection/inflammation-related variables was associated with the success of sperm retrieval or inflammatory lesions in the testis. The high prevalence of urogenital infection/inflammation among azoospermic men underpins their role as significant aetiologic factors in male infertility. However, this observation does not refer to the chances of sperm retrieval at the time of surgery/TESE.