Biology subjects

Rinaldi, V.

Publications and source records attributed to Rinaldi, V..

9 recordsLinked to original sources

bioRxiv2024

A single cell atlas of the mouse seminal vesicle

During mammalian reproduction, sperm are delivered to the female reproductive tract bathed in a complex medium known as seminal fluid, which plays key roles in signaling to the female reproductive tract and in nourishing sperm for their onwards journey. Along with minor contributions from the prostate and the epididymis, the majority of seminal fluid is produced by a somewhat understudied organ known as the seminal vesicle. Here, we report the first single-cell RNA-seq atlas of the mouse seminal vesicle, generated using tissues obtained from 23 mice of varying ages, exposed to a range of dietary challenges. We define the transcriptome of the secretory cells in this tissue, identifying a relatively homogeneous population of the epithelial cells which are responsible for producing the majority of seminal fluid. We also define the immune cell populations - including large populations of macrophages, dendritic cells, T cells, and NKT cells - which have the potential to play roles in producing various immune mediators present in seminal plasma. Together, our data provide a resource for understanding the composition of an understudied reproductive tissue with potential implications for paternal control of offspring development and metabolism.

genomics↗

bioRxiv2022

Evidence for RNA or protein transport from somatic tissues to the male reproductive tract in mouse

The development of tools to manipulate the mouse genome, including knockout and transgenic technology, revolutionized our ability to explore gene function in mammals. Moreover, for genes that are expressed in multiple tissues or at multiple stages of development, the use of tissue-specific expression of the Cre recombinase allows gene function to be perturbed in specific cell types and/or at specific times. However, it is well known that putative tissue-specific promoters often drive unanticipated "off target" expression. In our efforts to explore the biology of the male reproductive tract, we unexpectedly found that expression of Cre in the central nervous system resulted in recombination in the epididymis, a tissue where sperm mature for ~1-2 weeks following the completion of testicular development. Remarkably, we not only observed reporter expression in the epididymis when Cre expression was driven from neuron-specific transgenes, but also when Cre expression in the brain was induced from an AAV vector carrying a Cre expression construct. A surprisingly wide range of Cre drivers - including six different neuronal promoters as well as the adipose-specific AdipoQ Cre promoter - exhibited off target recombination in the epididymis, with a subset of drivers also exhibiting unexpected activity in other tissues such as the reproductive accessory glands. Finally, using a combination of parabiosis and serum transfer experiments, we find evidence supporting the hypothesis that Cre may be trafficked from its cell of origin to the epididymis through the circulatory system. Together, our findings should motivate extreme caution when interpreting conditional alleles, and suggest the exciting possibility of inter-tissue RNA or protein trafficking in modulation of reproductive biology.

genetics↗

bioRxiv2021

Enrichment analysis of GWAS data in autoimmunity delineates the multiple sclerosis-Epstein Barr virus association

We exploited genetic information to assess non-genetic influences in autoimmunity. We isolated gene modules whose products physically interact with environmental exposures related to autoimmunity, and analyzed their nominal statistical evidence of association with autoimmune and non-autoimmune diseases in genome-wide association studies (GWAS) data. Epstein Barr virus (EBV) and other Herpesviruses interactomes emerged as specifically associated with multiple sclerosis (MS), possibly under common regulatory mechanisms. Analyses of MS blood and brain transcriptomes, cytofluorimetric studies of endogenous EBV-infected lymphoblastoid lines, and lesion immunohistochemistry, confirmed a dysregulation of MS-associated EBV interactors, suggesting their contribution to CD40 signaling alterations in MS. These interactors resulted enriched in modules from inherited axonopathies-causing genes, supporting a link between EBV and neurodegeneration in MS, in accord with the observed transcriptomic dysregulations in MS brains. They were also enriched with top-ranked pharmaceutical targets prioritized on a genetic basis. This study delineates a disease-specific influence of herpesviruses on MS biology.

neuroscience↗

bioRxiv2021

GWAS-associated variants, non-genetic factors and transient transcriptome in Multiple Sclerosis etiopathogenesis: a colocalization analysis

A clinically actionable understanding of multiple sclerosis (MS) etiology goes through GWAS interpretation, prompting research on new gene regulatory models. We previously suggested a stochastic etiologic model where small-scale random perturbations could reach a threshold for MS development. The recently described mapping of the transient transcriptome (TT), including intergenic and intronic RNAs, seems appropriate to verify this model through a rigorous colocalization analysis. We show that genomic regions coding for the TT were significantly enriched for MS-associated GWAS variants and DNA binding sites for molecular transducers mediating putative, non-genetic, etiopathogenetic factors for MS (e.g., vitamin D deficiency, Epstein Barr virus latent infection, B cell dysfunction). These results suggest a model whereby TT-coding regions are hotspots of convergence between genetic ad non-genetic factors of risk/protection for MS, and plausibly for other complex disorders. Our colocalization analysis also provides a freely available data resource (www.mscoloc.com) for future research on MS transcriptional regulation.

neuroscience↗

bioRxiv2020

Deficient spermiogenesis in mice lacking Rlim

The X-linked gene Rlim plays major roles in female mouse development and reproduction, where it is crucial for the maintenance of imprinted X chromosome inactivation in extraembryonic tissues of embryos. However, while females carrying a systemic Rlim knockout (KO) die around implantation, male Rlim KO mice appear healthy and are fertile, raising questions as to the pressures driving Rlim gene selection during evolution. Here we report an important role for Rlim in testis where it is highly expressed in post-meiotic round spermatids as well as in Sertoli cells. Systemic deletion of the Rlim gene leads to lower numbers of mature sperm that contains excess cytoplasm, leading to decreased sperm motility and in vitro fertilization rates. Targeting the conditional Rlim cKO specifically to the spermatogenic cell lineage largely recapitulates this phenotype. These results reveal functions of Rlim in male reproduction specifically in round spermatids during spermiogenesis with likely evolutionary implications.

developmental biology↗

bioRxiv2020

Cytosine methylation dynamics during post-testicular sperm maturation in mammals

Beyond the haploid genome, mammalian sperm contribute a payload of epigenetic information which can modulate offspring phenotypes. Recent studies have shown that the small RNA payload of sperm undergoes extensive remodeling during post-testicular maturation in the epididymis. Intriguingly, epididymal maturation has also been linked to changes in the sperm methylome, suggesting that the epididymis might play a broader role in remodeling the sperm epigenome. Here, we build on prior studies of the maturing sperm methylation landscape, further characterizing the genome-wide methylation landscape in seven germ cell populations collected from throughout the male reproductive tract. Overall, we find very few changes in the cytosine methylation landscape between testicular germ cell populations and cauda epididymal sperm, demonstrating that the sperm methylome is largely stable throughout post-testicular maturation. Intriguingly, although our sequencing data suggested that caput epididymal sperm exhibit a highly unusual methylome, follow-up studies revealed that this resulted from contamination of caput sperm by extracellular DNA. Extracellular DNA formed web-like structures that ensnared sperm, was present only in the caput epididymis of virgin males, where it was associated with citrullinated histone H3 and presumably resulted from a PAD-driven genome decondensation process. Taken together, our data emphasize the stability of the cytosine methylation landscape in mammalian sperm, and identify a surprising but transient period during which immature sperm are associated with extracellular DNA.

developmental biology↗

bioRxiv2020

An atlas of cell types in the mammalian epididymis and vas deferens

Following spermatogenesis in the testis, mammalian sperm continue to mature over the course of approximately 10 days as they transit a long epithelial tube known as the epididymis. The epididymis is comprised of multiple segments/compartments that, in addition to concentrating sperm and preventing their premature activation, play key roles in remodeling the protein, lipid, and RNA composition of maturing sperm. In order to understand the complex roles for the epididymis in reproductive biology, we generated a single cell atlas of gene expression from the murine epididymis and vas deferens. We recovered all the key cell types of the epididymal epithelium, including principal cells, clear cells, and basal cells, along with associated support cells that include fibroblasts, smooth muscle, macrophages and other immune cells. Moreover, our data illuminate extensive regional specialization of principal cell populations across the length of the epididymis, with a substantial fraction of segment-specific genes localized in genomic clusters of functionally-related genes. In addition to the extensive region-specific specialization of principal cells, we find evidence for functionally-specialized subpopulations of stromal cells, and, most notably, two distinct populations of clear cells. Analysis of ligand/receptor expression reveals a network of potential cellular signaling connections, with several predicted interactions between cell types that may play roles in immune cell recruitment and other aspects of epididymal function. Our dataset extends on existing knowledge of epididymal biology, and provides a wealth of information on potential regulatory and signaling factors that bear future investigation.

developmental biology↗

bioRxiv2019

Signaling to TRP53 and TAp63 from CHK1/CHK2 is responsible for elimination of most oocytes defective for either chromosome synapsis or recombination

Eukaryotic organisms have evolved mechanisms to prevent the accumulation of cells bearing genetic aberrations. This is especially crucial for the germline, because fecundity, and fitness of progeny would be adversely affected by an excessively high mutational incidence. The process of meiosis poses unique problems for mutation avoidance, due to the requirement for SPO11-induced programmed double strand breaks (DSBs) in recombination-driven pairing and segregation of homologous chromosomes. Mouse meiocytes bearing unrepaired meiotic DSBs or unsynapsed chromosomes are eliminated before completing meiotic prophase I. In previous work, we showed that checkpoint kinase 2 (CHK2; CHEK2), a canonical DNA damage response protein, is crucial for eliminating not only oocytes defective in meiotic DSB repair (e.g. Trip13Gt mutants), but also asynaptic Spo11-/- oocytes that accumulate a threshold level of spontaneous DSBs. However, rescue of such oocytes by Chk2 deficiency was incomplete, raising the possibility that a parallel checkpoint pathway(s) exists. Here, we show that mouse oocytes lacking both TAp63 and TRP53 protects nearly all Spo11-/- and Trip13Gt/Gt oocytes from elimination. We present evidence that checkpoint kinase I (CHK1; CHEK1), which is known to signal to TRP53, also becomes activated by persistent DSBs in oocytes, and to an increased degree when CHK2 is absent. The combined data indicate that nearly all oocytes reaching a threshold level of unrepaired DSBs are eliminated by a semi-redundant pathway of CHK1/CHK2 signaling to TRP53/TAp63.

genetics↗

bioRxiv2017

A Single Checkpoint Pathway Eliminates Mouse Oocytes With DNA Damage Or Chromosome Synapsis Failure

Pairing and synapsis of homologous chromosomes during meiosis is crucial for producing genetically normal gametes, and is dependent upon repair of SPO11-induced double stranded breaks (DSBs) by homologous recombination. To prevent transmission of genetic defects, diverse organisms have evolved mechanisms to eliminate meiocytes containing unrepaired DSBs or unsynapsed chromosomes. Here, we show that the CHK2 (CHEK2)-dependent DNA damage checkpoint culls not only recombination-defective mouse oocytes, but also SPO11-deficient oocytes that are severely defective in homolog synapsis. The checkpoint is triggered by spontaneous DSBs that arise in late prophase I, accumulating above the checkpoint activation threshold ([~]10 DSBs) because presence of HORMAD1/2 on unsynapsed chromosome axes prevents their repair. Furthermore, Hormad2 deletion rescued fertility and meiotic DSB repair of oocytes containing a synapsis-proficient, non-crossover recombination defective mutation in a gene (Trip13) required for removal of HORMADs from synapsed chromosomes, indicating that a substantial fraction of meiotic DSBs are normally repaired by intersister recombination in mice.

genetics↗