Biology subjects

Luo, P. M.

Publications and source records attributed to Luo, P. M..

5 recordsLinked to original sources

bioRxiv2026

Transient architecture of the embryonic pancreas determines endocrine mass

During organogenesis, epithelial tissues undergo extensive three-dimensional (3D) remodeling while simultaneously generating specialized cell types. Whether these transient architectural states actively instruct lineage allocation remains unclear. Here we identify a morphogenetic stage in which resolution of epithelial stratification is required for lineage allocation and establishment of endocrine cell mass. We show that loss of the Hippo pathway regulator Merlin disrupts lumen morphogenesis and prevents formation of the transient 3D epithelial architecture that characterizes normal pancreas development. Failure to establish this architectural state alters lineage allocation, impairing acinar differentiation, markedly reducing adult endocrine cell mass, and disrupting glucose homeostasis. Mosaic analyses reveal that these lineage defects arise non-cell autonomously, demonstrating that epithelial architecture itself instructs cell fate decisions. Mechanistically, Merlin coordinates PI3K-regulated polarized membrane trafficking required for apical membrane biogenesis and lumen formation. Together, these findings identify Merlin-dependent membrane trafficking as a mechanism coupling epithelial morphogenesis to lineage allocation and demonstrate that transient developmental architectures can determine the cellular composition of mature organs.

developmental biology↗

bioRxiv2025

Zonal endothelial cell heterogeneity underlies murine renal vascular development.

The renal vasculature consists of highly specialized blood vessels that carry out distinct physiological functions. Defining their transcriptional signatures and tracing their developmental ontogeny has thus far been challenging due to a lack of regionally specific endothelial biomarkers. Here, we performed single nuclear RNA sequencing (snucRNA-Seq) to interrogate embryonic renal endothelial cells. We identified nine different endothelial cell types, and validated expression of novel candidates using multiplex RNAScope. We interrogate biological characteristics, including cell cycle stage, of developmental blood vessels with a variety of in vivo tools. Using genetic tools based on expression of tip cell marker Esm1, we performed detailed lineage tracing, demonstrating multi-clonal and multi-directional endothelial contribution to glomerular vasculature. Together, this study provides the first validated, tool-focused developmental atlas of the murine renal vasculature and elucidates several novel cellular mechanisms of nephron vascularization.

developmental biology↗

bioRxiv2024

Integration of spatial and single nucleus transcriptomics to map gene expression in the developing mouse kidney

The kidney is a complex organ requiring tightly coordinated interactions between epithelial, endothelial, and mesenchymal cells during development. Congenital kidney defects can result in kidney disease and renal failure, highlighting the importance of understanding kidney formation mechanisms. Advances in RNA sequencing have revealed remarkable cellular heterogeneity, especially in the kidney stroma, though relationships between stromal, epithelial, and endothelial cells remain unclear. This study presents a comprehensive gene expression atlas of embryonic and postnatal kidneys, integrating single-nucleus and in situ RNA sequencing data. We developed the Kidney Spatial Transcriptome Analysis Tool (KSTAT), enabling researchers to identify cell locations, predict cell-cell communication, and map gene pathway activity. KSTAT revealed significant heterogeneity among embryonic kidney pericytes, providing a critical resource for hypothesis generation and advancing knowledge of kidney development and disease.

developmental biology↗

bioRxiv2023

Stromal netrin-1 coordinates renal arteriogenesis and mural cell differentiation

The kidney vasculature has a uniquely complex architecture that is essential to proper renal function. Little is known about the molecular mechanisms that direct where and when blood vessels form during kidney development. We identified a regionally-restricted, stroma-derived signaling molecule, netrin-1 (Ntn1), as a putative regulator of vascular patterning. We generated a stromal progenitor-specific knockout of netrin-1 (Ntn1SPKO) that resulted in smaller postnatal kidneys with altered epithelial development and profound defects in arterial and capillary architecture. We also found significant loss of arterial vascular smooth muscle cell (vSMC) coverage and ectopic smooth muscle cell deposition at the kidney cortex. Transcriptomic analysis of Ntn1SPKO kidneys revealed downregulation of Klf4, which we find expressed in stromal progenitors. Deletion of Klf4 in the stroma largely phenocopies loss of Ntn1, and expression of Klf4 in Ntn1SPKO kidneys rescues ectopic vSMC deposition. Vascular defects observed in Ntn1SPKO are transient, as both arterial and smooth muscle coverage defects resolve late in development, however ectopic peripheral smooth muscle perdures perinatally. These data suggest a stromal-intrinsic Ntn1-Klf4 axis acting as an essential mediator of stromal crosstalk and vascular progenitor differentiation.

developmental biology↗

bioRxiv2019

Mapping interactions of microbial metabolites and human receptors

Despite evidence linking the human microbiome to health and disease, the mechanistic details of how the microbiota affects human physiology remain largely unknown. Metabolites encoded by bacteria are expected to play an integral role in the microbiotas effect on its human host. Assigning function to these metabolites is therefore critical to determining the molecular underpinnings of the host-microbe relationship and ultimately developing microbiota inspired therapies. Here we use large-scale functional screening of small molecules produced by individual members of a simplified human microbiota to identify bacterial metabolites that agonize G-protein coupled receptors (GPCR). This analysis revealed a complex network of metabolite host receptor interactions and guided our identification of multiple microbiota derived agonists of GPCRs associated with diverse biological functions within the nervous and immune systems, among others. Collectively, the metabolite-receptor pairs we uncovered indicate that diverse aspects of human health are potentially modulated by structurally simple metabolites arising from primary bacterial metabolism.\n\nStatement of SignificanceBacteria residing within the human body have been shown to influence human health. It is likely that physiological responses to the human microbiota are mediated by the collection of small molecules encoded within these bacteria. In this study we use direct functional screening of small molecules produced by individual members of a simplified human microbiota to identify new G protein coupled receptor-metabolite interactions that seek to explain the molecular underpinnings of the microbiotas influence on its human host.

microbiology↗