Biology subjects

Plat, A.

Publications and source records attributed to Plat, A..

3 recordsLinked to original sources

bioRxiv2025

The landscape of tertiary lymphoid structures in endometrial cancer revealed through harmonized multi-level transcriptomics

Tertiary lymphoid structures (TLSs) are ectopic lymphoid tissues that form within tumors. TLSs are associated with improved prognosis and better responses to immune checkpoint inhibitors (ICI) in cancer. However, the contribution of genetic, immune, and (micro)environmental factors to TLS formation and function remain incompletely understood. Using harmonized bulk and single-cell RNA-sequencing coupled with spatial transcriptomics, we present a comprehensive characterization of tumor-associated TLSs in endometrial cancer (EC). Our integrated datasets reveal the cellular architecture of TLSs, their organizing principles--including chemokine-receptor gradients--and TLS activity compared to paired tumor-draining lymph nodes, as well as spatial preferences in IgA/IgG plasma cell and T cell distribution. We identified a consensus set of transcriptional components that independently predict the presence of TLS in EC. Furthermore, we demonstrate that clinical neoadjuvant ICI in EC patients shifts the cellular balance in favor of immunogenic CXCL13+ PDCD1+ T cells, providing a mechanistic insight into ICI-induced TLSs formation. Our data offers a systems-level understanding of TLSs and a roadmap for their therapeutic exploitation.

immunology↗

bioRxiv2022

Regulating the timing of enhancer transitions is key to defining sharp boundaries of Fushi tarazu expression in the Drosophila embryo

Coordinating the action of different enhancers is crucial to correctly specify cell fate decisions during development. Yet it remains poorly understood how the activity of multiple enhancers is choregraphed in time. To shed light on this question we used new live imaging approaches to quantify transcription and protein expression in single cells of Drosophila melanogaster embryos. We employed these tools to dissect the regulation of Fushi tarazu (Ftz), a transcription factor expressed in a series of stripes by two distinct enhancers: autoregulatory and zebra. The anterior edges of the Ftz stripes are sharply defined and specify essential signaling centers. Here, we determined the time at which each boundary cell commits to either a high-Ftz or low-Ftz fate using dynamic features of time-resolved Ftz protein traces. By following the activity of each enhancer individually, we showed that the autoregulatory enhancer does not establish this fate choice. Instead, it perpetuates the decision defined by zebra. This is contrary to the prevailing view that autoregulation drives the fate decision by causing bi-stable Ftz expression. Furthermore, we showed that the autoregulatory enhancer is not activated based on a Ftz concentration threshold, but through a timing-based mechanism. We hypothesize that this is regulated by a set of pioneer-like transcription factors, which have recently been shown to act as timers in the embryo. Our work provides new insight into the genetic mechanisms that directly regulate the dynamics of gene regulatory networks, and supports the emerging view that this regulation is vital for reliable cell fate specification.

developmental biology↗

bioRxiv2018

TGF-β induced CXCL13 in CD8+ T cells is associated with tertiary lymphoid structures in cancer

Coordinated immune responses against human tumors are frequently characterized by tertiary lymphoid structures (TLS) which predict improved prognosis. The development of TLS is dependent on the chemokine CXCL13, reported to be secreted by dendritic cells and follicular helper T cells only. We report the unexpected finding that CXCL13 is also secreted by activated CD8+ T cells following stimulation by transforming growth factor beta (TGF-{beta}). Using single cell RNA sequencing we found that expression of CXCL13 in CD8+ T cells was restricted to the intraepithelial CD103+ population. Accordingly, CD8+ T cells activated in the presence of TGF-{beta} simultaneously upregulated CD103 and secreted CXCL13. CXCL13 expression was strongly correlated with neo-antigen burden and cytolytic gene signatures in bulk tumors. In line with this, TLS were abundant in neo-antigen-high, CD103+ T cell-enriched tumors. TGF-{beta} thus appears to play a role in coordinating immune responses against human tumors through CD8-dependent CXCL13-associated formation of TLS.

immunology↗