Biology subjects

Battistone, M. A.

Publications and source records attributed to Battistone, M. A..

6 recordsLinked to original sources

bioRxiv2025

Immunomodulatory Functions of Intercalated Cells in Kidney Autoimmunity

Various autoimmune diseases frequently cause both acute and chronic kidney injuries through complex mechanisms involving autoantibodies and cellular immune responses that result in tissue damage. Intercalated cells (ICs), specialized renal tubular epithelial cells responsible for proton secretion, are strategically positioned at the epithelial-immune interface, making them ideal sensors of stress signals and potential triggers of immune responses. This study investigates the molecular mechanisms by which ICs interact with immune cells to maintain renal immune homeostasis and contribute to the development of autoimmune kidney disease. We depleted Foxp3 regulatory T cells (Tregs) by injecting diphtheria toxin (DT) into male and female Foxp3-DTR mice. Two weeks after depletion, we observed autoimmune inflammation marked by increased renal immune infiltration, including neutrophils, macrophages, and subsets of T and B cells, along with the formation of ectopic lymphoid-like structures and enhanced antigen presentation. We found higher levels of renal autoantibodies in urine and serum, with antibodies depositing in glomeruli and tubules. Our analysis identified several renal antigens targeted by autoantibodies, suggesting their potential role in antibody-mediated renal injury. Kidney damage included smaller glomeruli, proximal tubular injury, an increased urine albumin/creatinine ratio, and decreased urine output. Disruption of immune tolerance led to the upregulation of inflammasome-related genes and IL-33 in ICs, which acts as a key alarmin signaling damage and promoting activation and expansion of Tregs. Our findings uncover a novel IC-Treg interaction mediated by the IL-33 pathway, revealing immune-regulating mechanisms that support renal immune tolerance. Although Tregs were initially depleted, a significant rebound in their numbers and function occurred. Understanding the cellular and molecular mechanisms behind autoimmune renal injury is crucial for developing targeted therapies and identifying appropriate biomarkers.

immunology↗

bioRxiv2025

Coordinated and compartmentalized functions of CAII and CAIV establish a dual pH-regulatory mechanism essential for sperm maturation and capacitation

Carbonic anhydrase II (CAII) and IV (CAIV) orchestrate pH regulation essential for male fertility through distinct cellular compartments, with CAII functioning intracellularly and CAIV GPI-anchored extracellularly in epididymal and vas deferens epithelia as well as on spermatozoa. These enzymes control pH environments required for sperm maturation and capacitation by regulating bicarbonate availability, which triggers soluble adenylyl cyclase/cAMP signaling, elevates intracellular pH (pHi), and enables motility activation. However, the specific contributions of CAII and CAIV to luminal pH and sperm pHi regulation remain unclear. Here, we show that genetic ablation of either CAII or CAIV in mice impairs normal luminal acidification in the male reproductive tract and unexpectedly lowers the basal pHi of sperm. This lower basal pHi blunts subsequent intracellular alkalinization, thereby diminishing the activation of pH-sensitive CatSper Ca2+ channels essential for hyperactivated motility. Mechanistically, we demonstrate that this basal pHi reduction occurs independently of the CatSper channel itself, but it is phenocopied in K+channel Slo3-deficient sperm, suggesting a homeostatic link between flagellar pH and membrane potential. Super-resolution imaging reveals that CAII is located within the flagellum near the CatSper channel in the principal piece, while CAIV is distributed along the entire flagellar membrane. Together, our findings demonstrate that CAII and CAIV employ spatially coordinated mechanisms to regulate pH. By maintaining an acidic luminal environment for sperm maturation and priming the subsequent alkalinization of sperm pHi, these enzymes modulate downstream ion channel activity to govern sperm motility and fertility. One-sentence summarySpatially coordinated carbonic anhydrases II and IV govern sperm motility by establishing the dual-compartment pH environments necessary to activate downstream flagellar ion channels.

cell biology↗

bioRxiv2025

Depletion of CX3CR1+ macrophages results in disrupted functionality and immune surveillance within epididymis and testis

A finely tuned immune regulation within the epididymis and testis is essential for male reproductive health. This balance is especially critical in the epididymis, where sperm mature and ascending infections frequently disrupt homeostasis, resulting in regionally different immune responses and potential long-term fertility impairments. We previously demonstrated that the epididymis harbors a region-specific immunological scaffold, with CX3CR1+ macrophages as the most prominent epithelium-associated immune cell population. Here, we established a transgenic mouse model to selectively deplete these intraepithelial CX3CR1+ macrophages within the epididymis, resulting in focal epithelial damage and impaired sperm maturation processes essential for proper sperm functionality. Additionally, a mild reduction of the testicular macrophage pool resulted in transient disruptions in spermatogenesis and steroidogenesis. Although the macrophage niche was repopulated after depletion, the newly recruited cells displayed altered phenotypes consistent with persistent sperm alterations. Following infection with uropathogenic Escherichia coli (UPEC), macrophage-depleted mice exhibited exacerbated immune responses - particularly in normally protected proximal epididymal regions - with earlier onset and more severe tissue damage. Transcriptomic analysis revealed a failure to restrain inflammatory responses, especially in genes involved in immune regulation and antibacterial defense, accompanied by elevated immune cell infiltration in infected macrophage-depleted mice. Overall, our findings confirm a crucial role for CX3CR1 macrophages in preserving epithelial integrity and modulating immune responses, supporting a stable tissue environment necessary for efficient organ function of both epididymis and testis. Significance statementMaintaining immune balance in the epididymis is essential for tissue health and protection against ascending infections. Using a transgenic mouse model that allows for selective depletion of CX3CR1 macrophages, this study examines their role in both the epididymis and testis under normal and infectious conditions. The results show that the removal of these macrophages causes localized epithelial damage, changes in immune cell make-up, and increased inflammation in the epididymis after bacterial infection, while also causing mild, reversible problems with spermatogenesis and steroid production in the testis. These findings support the idea that CX3CR1 macrophages contribute to region-specific immune regulation and epithelial stability--key features for keeping the tissue environment suitable for proper sperm development.

immunology↗

bioRxiv2025

Proton-secreting cells modulate mucosal immune surveillance in the male reproductive tract

Proton-secreting cells in various organs, such as the kidney and epididymis, regulate pH balance, maintaining cellular homeostasis, and supporting key physiological processes. More recently, these specialized cells have emerged as key contributors to mucosal immunity, orchestrating immune activation. Epididymitis is an inflammatory condition that significantly impacts male fertility, often due to a lack of diagnosis and treatment. This study explores the involvement of region-specific epididymal proton-secreting clear cells (CCs) in the immune response by interacting with the immune system during LPS-induced mouse epididymitis. We found that in response to LPS, CCs rapidly shifted to a proinflammatory phenotype, marked by the upregulation of cytokines and chemokines, alongside the downregulation of genes involved in sperm maturation. Morphological changes in CCs, including increased apical blebs and altered shape across different epididymal segments, suggest their active role in immune responses. Moreover, mononuclear phagocytes (MPs) reduced their luminal-reaching projections in the proximal epididymis after the LPS challenge. This bacteria antigen triggered the migration of dendritic cells and neutrophil infiltration in the distal epididymis. These immune landscape alterations contributed to epithelial damage and impaired sperm maturation, as evidenced by decreased sperm motility following LPS injection. Our findings indicate that proton-secreting cells are immune gatekeepers in the epididymis, initiating immune responses and disrupting sperm maturation. This research enhances the understanding of epithelial immunoregulation and will help to develop novel diagnostic and therapeutic strategies for epididymitis and male infertility. Furthermore, insights into CC-mediated immune responses could inform the development of new approaches for male contraception.

developmental biology↗

bioRxiv2024

Chronic inflammation drives epididymal tertiary lymphoid structure formation and autoimmune fertility disorders

The incomplete understanding of epididymal mucosal immunity is a significant contributing factor to the classification of many male infertility cases as idiopathic. Conditions that disrupt the immune balance in the male reproductive tract, such as vasectomy and infections, can expose sperm to the immune system, leading to increased production of anti-sperm antibodies (ASAs) and subsequent reproductive challenges. Regulatory T cells (Tregs) regulate inflammation and maintain sperm tolerance. In a murine model, we demonstrated that disrupting sperm immunotolerance induces chronic autoimmune responses characterized by antibody production targeting sperm and reproductive tissue autoantigens and unique tissue-specific immune cell signatures in the epididymis and testis. Such inflammatory features impair sperm function, contribute to epididymal damage, and drive sustained male subfertility. Tertiary lymphoid structures (TLSs) were formed within the epididymis after Treg depletion, defined by clusters of heterogenous B and T cells, fibroblasts, and endothelial cells. These ectopic structures perpetuate inflammation and lower the activation threshold for future immune threats. Similar isotypes of autoantibodies were detected in the seminal plasma of infertile patients, suggesting shared mechanistic pathways between mice and humans. Overall, we provide an in-depth understanding of the diverse B- and T-cell dynamics and TLS formation during epididymitis to develop precision-targeted therapies for infertility and chronic inflammation. Additionally, this immunological characterization of the epididymal microenvironment has the potential to identify novel targets for the development of male contraceptives. One Sentence SummaryUnderstanding the epididymal immune cell landscape dynamics aids in developing targeted therapies for infertility and contraception.

immunology↗

bioRxiv2017

Transcriptomes of major renal collecting-duct cell types in mouse identified by single-cell RNA-Seq

Prior RNA sequencing (RNA-Seq) studies have identified complete transcriptomes for most renal epithelial cell types. The exceptions are the cell types that make up the renal collecting duct, namely intercalated cells (ICs) and principal cells (PCs), which account for only a small fraction of the kidney mass, but play critical physiological roles in the regulation of blood pressure, extracellular fluid volume and extracellular fluid composition. To enrich these cell types, we used fluorescence-activated cell sorting (FACS) that employed well established lectin cell surface markers for PCs and type B ICs, as well as a newly identified cell surface marker for type A ICs, viz. c-Kit. Single-cell RNA-Seq using the 1C- and PC-enriched populations as input enabled identification of complete transcriptomes of A-ICs, B-ICs and PCs. The data were used to create a freely-accessible online gene-expression database for collecting duct cells. This database allowed identification of genes that are selectively expressed in each cell type including cell-surface receptors, transcription factors, transporters and secreted proteins. The analysis also identified a small fraction of hybrid cells expressing both aquapor{inverted exclamation}n-2 and either anion exchanger 1 or pendrin transcripts. In many cases, mRNAs for receptors and their ligands were identified in different cells (e.g. Notch2 chiefly in PCs vs Jag1 chiefly in ICs) suggesting signaling crosstalk among the three cell types. The identified patterns of gene expression among the three types of collecting duct cells provide a foundation for understanding physiological regulation and pathophysiology in the renal collecting duct.\n\nSIGNIFICANCE STATEMENTA long-term goal in mammalian biology is to identify the genes expressed in every cell type of the body. In kidney, the expressed genes (\"transcriptome\") of all epithelial cell types have already been identified with the exception of the cells that make up the renal collecting duct, responsible for regulation of blood pressure and body fluid composition. Here, a technique called \"single-cell RNA-Seq\" was used in mouse to identify transcriptomes for the major collecting-duct cell types: type A intercalated cells, type B intercalated cells and principal cells. The information was used to create a publicly-accessible online resource. The data allowed identification of genes that are selectively expressed in each cell type, informative for cell-level understanding of physiology and pathophysiology.

physiology↗