Ngwa, E. M. | Search bioRxiv

bioRxiv2025

Development of the Early Childhood Duodenum across Ancestry, Geography and Environment

During early childhood, the proximal small intestinal mucosa plays a central role in growth, metabolism, immune priming, and neuronal development. Yet the cellular architecture and environmental responsiveness of the human small intestinal mucosa during this period remain poorly defined. Here, we generate a comprehensive cellular and spatial map of the duodenum from 87 children aged 6 months to 13 years, representing diverse ancestries and geographic contexts. This atlas integrates single-cell transcriptomic and spatial profiling with data on diet, social drivers of health, and environmental exposures. Using these data, we define mucosal cellular composition and chart its developmental trajectory in early childhood. Comparative analyses of children residing in the United States (US) and Pakistan reveal a differentiated enterocyte subset expressing the aquaglyceroporin, AQP10 (AQP10+ enterocyte), that is enriched in children from the US. We show that emergence of this enterocyte state depends on lipid exposure to intestinal stem cells and correlates with dietary fat intake. We also identify a previously-undescribed thyrotropin-releasing hormone (TRH+) enteroendocrine cell and provide evidence for a local endocrine-epithelial-lymphocyte circuit. Our work establishes a detailed framework for pediatric duodenal mucosal development and illuminates how intestinal cellular dynamics are shaped by age and environment.

developmental biology↗

bioRxiv2022

The pore-forming protein gasdermin D is a cellular redox sensor

Reactive oxygen species (ROS) affect inflammation and immunity in a multitude of ways, in particular in the context of the signaling pathways that determine cell fate. Inflammasomes are multiprotein cytoplasmic complexes whose pyroptosis-inducing activities are controlled by ROS. Our knowledge of how ROS mediates inflammasome activities is largely based on studies of the initiating events in these pathways. Herein, we show that ROS controls the terminal events in the pyroptosis pathways. We found that ROS oxidizes the protein gasdermin D (GSDMD) and promotes its assembly into a death-inducing pore forming complex. Mechanistically, ROS enhances GSDMD-mediated pyroptosis in an intrinsic manner, likely through oxidative modification of a specific cysteine residue (C192). Diverse ROS sources promote GSDMD oxidation, ranging from homeostatic control via the Ragulator-Rag complex, to inducible control via diverse microbial products and environmental toxins. These findings expand the steps in the inflammasome pathway that are controlled by ROS and suggest that GSDMD operates as a pyroptosis-inducing redox sensor.

immunology↗