Biology subjects

Dobesova, M.

Publications and source records attributed to Dobesova, M..

4 recordsLinked to original sources

bioRxiv2025

Claudin 1-mediated positioning of DC1 to mTECs is essential for antigen transfer-coupled DC1 maturation and maintenance of central tolerance

The mechanisms of central tolerance, which rely on the presentation of self-antigens by medullary thymic epithelial cells (mTECs) and DCs, prevent autoimmunity by eliminating self-reactive T-cells. While mTECs produce self-antigens in an autonomous manner, DCs acquire them from mTECs via cooperative antigen transfer (CAT). Our recent data showed that preferential pairing occurs between distinct subsets of mTECs and DCs in CAT, providing a rationale for the existence of molecular determinants which control such pairing and the outcome of central tolerance. Here, we compared the transcriptomes of CAT-experienced and -inexperienced DCs and identified Claudin 1 as a molecule involved in CAT-coupled type 1 DC (DC1) maturation. By mapping thymic DC1 heterogeneity, we identified their early and late maturation states. DC1-specific ablation of Claudin 1 led to a reduction in CAT-experienced late mature DC1s and hampered DC1 maturation. These phenotypes correlated with the displacement of DC1s from the vicinity of mTECs. This translated into impaired Treg selection and clonal deletion of TRA-specific T-cells manifested via a break in tolerance and symptoms of multi-organ autoimmunity. Collectively, our results identify thymic DC1-derived Claudin 1 as a regulator of immune tolerance. One Sentence SummaryThe expression of Claudin 1 on type 1 dendritic cells regulates their proximity to mTECs, which is required for effective antigen transfer coupled with DC1 maturation and establishment of T-cell tolerance.

immunology↗

bioRxiv2023

A virally encoded high resolution screen of cytomegalovirus host dependencies

Genetic screens have transformed our ability to interrogate cellular factor requirements in infection, yet current approaches are limited in their sensitivity, biased towards early stages of infection and provide only simplistic phenotypic information which is often based on infected cell survival. Here, by engineering human cytomegalovirus to express sgRNA libraries directly from the viral genome, we developed a sensitive, versatile, viral centric approach that allows profiling of different stages along viral infection in a pooled format. Using this approach, which we termed VECOS (Virus Encoded CRISPR-based direct readOut Screening system), we identified hundreds of novel host dependency and restriction factors and quantified their direct effects on viral genome replication, viral particle secretion and infectiousness of secreted particles, providing a multi-dimensional perspective on viral-host interactions. These high resolution measurements reveal that perturbations that alter late stages in HCMV life cycle mostly regulate HCMV particle quality rather than quantity, defining correct virion assembly as a critical stage that is heavily reliant on viral-host interactions. Overall, VECOS facilitates systematic high resolution dissection of human proteins role along the infection cycle, providing a roadmap for in-depth dissection of host-herpesvirus interactions.

microbiology↗

bioRxiv2022

Epithelial antigen presentation controls commensal-specific intraepithelial T-cells in the gut

The expression of MHCII by intestinal epithelial cells (IEC) determines the severity of intestinal immunopathological reactions. However, the function of MHCII on IEC under homeostatic conditions remains elusive. Here we report that MHCII expression on IECs is a hallmark of an adaptive wave of homeostatic intestinal immune responses to commensal segmented filamentous bacteria (SFB). Focusing on SFB-driven responses, we describe the expression pattern of MHCII and the associated antigen processing machinery among IEC subpopulations along with the cellular network that regulates MHCII induction. Furthermore, we show that SFB induce the accumulation of SFB-specific intraepithelial lymphocytes (IELs) that originate from conventional CD4+ T-cells. Importantly, induced IELs are dependent on the epithelial MHCII. Finally, we demonstrate that both epithelial MHCII and the IEL functionality regulate the epithelial turnover. This study describes the organization of a commensal-targeted, IEL-driven immune response that is controlled by IEC antigen presentation and ultimately regulates IEC turnover.

immunology↗

bioRxiv2021

A model of preferential pairing between epithelial and dendritic cells in thymic antigen transfer

Medullary thymic epithelial cells (mTECs) which produce and present self-antigens are essential for the establishment of central tolerance. Since mTEC numbers are limited, their function is complemented by thymic dendritic cells (DCs), which transfer mTEC-produced self-antigens via cooperative antigen transfer (CAT). While CAT is required for effective T cell selection, many aspects remain enigmatic. Given the recently described heterogeneity of mTECs and DCs, it is unclear whether the antigen acquisition from a particular TEC subset is mediated by preferential pairing with specific subset of DCs. Using several relevant Cre-based mouse models controlling the expression of fluorescent proteins, we found that in regards to CAT, each subset of thymic DCs preferentially targets distinct mTEC subset(s) and importantly, XCR1+ activated DCs represented the most potent subset in CAT. Interestingly, one thymic DC can acquire antigen repetitively and of these, monocyte-derived DCs (moDC) were determined to be the most efficient in repetitive CAT. moDCs also represented the most potent DC subset in the acquisition of antigen from other DCs. These findings suggest a preferential pairing model for the distribution of mTEC-derived antigens among distinct populations of thymic DCs.

immunology↗