Biology subjects

Willms, R. J.

Publications and source records attributed to Willms, R. J..

5 recordsLinked to original sources

bioRxiv2025

RANK-DEPENDENT CONTROL OF TUFT AND BEST4 CELL DEVELOPMENT IN THE INTESTINE

Specialist intestinal epithelial cells are critical for barrier integrity and immune responses at the mucosal boundary, yet the pathways that govern their development are incompletely defined. Here, we identify an essential role for TNFRSF11A/RANK in shaping intestinal epithelial specialization in zebrafish. Using lineage trajectory analysis, we identified two tuft cell subtypes, including a subtype enriched for expression of genes required to produce pro-inflammatory leukotrienes. We showed that RANK deficiency reduced the abundance of immune-regulatory tuft and BEST4 cells, increased goblet cell frequency, and promoted the accumulation of pro-inflammatory leukocytes in the gut. Functionally, we demonstrated that BEST4 cell numbers expand following infection with a pandemic strain of Vibrio cholerae, and that RANK deficiency enhances fish susceptibility to host colonization by Vibrio, implicating this lineage in host defenses against an enteric pathogen. Together, our findings implicate RANK signaling in intestinal epithelial diversification and immune regulation.

immunology↗

bioRxiv2024

The axillary lymphoid organ - an external, experimentally accessible immune organ in the zebrafish

Lymph nodes and other secondary lymphoid organs play critical roles in immune surveillance and immune activation in mammals, but the deep internal locations of these organs make it challenging to image and study them in living animals. Here, we describe a previously uncharacterized external immune organ in the zebrafish ideally suited for studying immune cell dynamics in vivo, the axillary lymphoid organ (ALO). This small, translucent organ has an outer cortex teeming with immune cells, an inner medulla with a mesh-like network of fibroblastic reticular cells along which immune cells migrate, and a network of lymphatic vessels draining to a large adjacent lymph sac. Noninvasive high-resolution imaging of transgenically marked immune cells can be carried out in the lobes of living animals, and the ALO is readily accessible to external treatment. This newly discovered tissue provides a superb model for dynamic live imaging of immune cells and their interaction with pathogens and surrounding tissues, including blood and lymphatic vessels. TeaserA newly characterized external zebrafish lymphoid organ provides a powerful model for live imaging of immune cell dynamics

developmental biology↗

bioRxiv2023

SINGLE CELL RESOLUTION OF THE ADULT ZEBRAFISH INTESTINE UNDER CONVENTIONAL CONDITIONS, AND IN RESPONSE TO AN ACUTE VIBRIO CHOLERAE INFECTION.

Vibrio cholerae is an aquatic bacterium that primarily infects the gastrointestinal tract, causing the severe and potentially deadly diarrheal disease, cholera. Despite the impact of Vibrio on global health, our understanding of host mucosal responses to the pathogen at the site of infection remains limited, highlighting a critical knowledge gap that must be addressed to develop more effective prevention and treatment strategies. Using a natural infection model, we combined physiological and single-cell transcriptomic studies to characterize adult zebrafish guts raised under conventional conditions and after a challenge with Vibrio. We discovered that Vibrio causes a mild mucosal immune response characterized by T cell activation and enhanced antigen capture in the epithelium. Additionally, we discovered that Vibrio suppresses host interferon signaling, and that ectopic activation of interferon significantly alters the course of infection. Notably, we also found that the adult zebrafish gut shares many similarities with mammalian counterparts, including the presence of previously undescribed Best4+ cells, tuft cells, and a population of basal cycling cells. These discoveries provide important insights into host-pathogen interactions and emphasize the utility of zebrafish as a natural model of Vibrio infection.

immunology↗

bioRxiv2020

A Cell Atlas of Microbe-Responsive Processes in the Zebrafish Intestine

Gut microbial products direct growth, differentiation, and development in the animal host. Disruptions to host-microbe interactions have profound health consequences, that include onset of chronic inflammatory illnesses. However, we lack system-wide understanding of cell-specific responses to the microbiome. We profiled transcriptional activity in individual cells from the intestine, and associated tissue, of zebrafish larvae that we raised in the presence or absence of a microbiome. We uncovered extensive cellular heterogeneity in the conventional zebrafish intestinal epithelium, including previously undescribed cell types with known mammalian homologs. By comparing conventional to germ-free profiles, we mapped microbial impacts on transcriptional activity in each cell population. We revealed intricate degrees of cellular specificity in host responses to the microbiome that included regulatory effects on patterning, metabolic and immune activity. For example, we showed that removal of microbes hindered pro-angiogenic signals in the developing vasculature, resulting in impaired intestinal vascularization. Our work provides a high-resolution atlas of intestinal cellular composition in the developing fish gut and details the effects of the microbiome on each cell type. Furthermore, we provide a web-based resource for single-cell gene expression visualization under conventional and germ-free conditions to facilitate exploration of this dataset.

developmental biology↗

bioRxiv2019

Myt1 kinase promotes mitotic cell cycle exit in Drosophila intestinal progenitor cells

Inhibitory phosphorylation of Cdk1 is a well-established mechanism for gating mitotic entry during development. However, failure to inhibit Cdk1 in adult organs causes ectopic cell division and tissue dysplasia, indicating that Cdk1 inhibition is also required for cell cycle exit. Two types of progenitor cells populate the adult Drosophila midgut: intestinal stem cells (ISCs) and post-mitotic enteroblasts (EBs). ISCs are the only mitotic cells under homeostatic conditions, dividing asymmetrically to produce quiescent EB daughter cells. We show here that Myt1, the membrane associated Cdk1 inhibitory kinase, is required for EB quiescence and subsequent differentiation. Loss of Myt1 disrupts EB cell cycle dynamics, promoting Cyclin A-dependent mitosis and accumulation of smaller progenitor-like cells that fail to differentiate. Thus, Myt1 inhibition of Cyclin A/Cdk1 functions as a mechanism for coupling cell cycle arrest with terminal cell differentiation in this developmental context.

developmental biology↗