Biology subjects

Azizoglu, D. B.

Publications and source records attributed to Azizoglu, D. B..

3 recordsLinked to original sources

bioRxiv2026

Spatiotemporal mapping of endothelial proliferative response in acute chemical liver injury

Endothelial cells are major contributors to liver injury response, regeneration, and chronic liver disease. Previous studies identified a proliferative endothelial response to acute liver injury; however, a comprehensive characterization of this adaptive response is missing. We have developed a novel pipeline for spatiotemporal analysis of proliferative response in the liver. We demonstrate that endothelial cells enter the cell cycle upon acute centrilobular injury with a delay compared to hepatocytes and in a spatially distinct pattern from hepatocytes. We show that endothelial cycling predominantly occurs in the pericentral zone, while hepatocyte cycling occurs uniformly throughout the lobule. Endothelial cycling in injured livers leads to heightened clonal expansion, and to serial division rarely observed in homeostatic livers. Consequently, injured lobules exhibit endothelial overabundance during regeneration. Our study provides an in-depth characterization of endothelial proliferative response to liver injury and establishes a novel pipeline for spatiotemporal mapping of hepatic cell states.

cell biology↗

bioRxiv2023

Liver size is predetermined in the neonate by adding lobules at the periphery

Organs vary in size between and within species to match organismal needs1,2. Decades-old theoretical work has proposed that scaling of organs and body parts relative to the body relies on the features of energy-transport systems, the vascular system in mammals3. Yet, experimental studies on whether or how vascularization helps determine organ size have lagged behind. The mammalian liver is a remarkable example, as liver size scales proportionally with high precision between individuals4. Here, we use quantitative clonal mapping, volumetric imaging, and genetic perturbations combined with novel molecular and genetic tools to identify the temporal and spatial constraints that establish mouse liver size. We find that adult liver size is predetermined during a neonatal period when new functional units, termed lobules, are added to the organ. New lobules are vascularized by prominent sprouting angiogenesis of the hepatic vein, restricted to the periphery of the organ. When Wnt signals are ablated in the single cell-layered mesothelium at the periphery, lobule growth fails, and the organ adopts a compromised size set point. Remarkably, within a week after birth and well before hepatocyte division stops, vein sprouting rapidly declines and lobule addition concludes, setting a limit on the final liver size. These findings posit that vascularization in the neonate constrains and helps determine adult liver size. Together, these results propose a novel, vasculature-centric experimental framework for studying organ size control and scaling in mammals.

developmental biology↗

bioRxiv2022

Rab11 is essential to pancreas morphogenesis, lumen formation and endocrine mass.

The molecular links between tissue-level morphogenesis and the differentiation of cell lineages in the pancreas remain elusive despite a decade of studies. We previously showed that in pancreas both these processes depend on proper lumenogenesis. The Rab GTPase Rab11 has been shown to be essential to epithelial lumen formation in vitro, however few studies have addressed its functions in vivo and none have tested its requirement in pancreas. Here, we show that Rab11 is critical to proper pancreas development. Co-deletion of the Rab11 isoforms Rab11A and Rab11B in the developing pancreatic epithelium (Rab11pancDKO) results in ~50% neonatal lethality, and surviving adult Rab11pancDKO mice exhibit defective endocrine function. Loss of Rab11 in the embryonic pancreas results in morphogenetic defects of the epithelium linked to defective lumen formation and interconnection. In contrast to wildtype cells, Rab11pancDKO cells attempt to form multiple lumens, resulting in a failure to coordinate a single apical membrane initiation site (AMIS) between groups of cells. We show that these defects are due to failures in vesicle trafficking, as apical components remain trapped within Rab11pancDKO cells. Together, these observations suggest Rab11 directly regulates epithelial lumen formation and morphogenesis. Our report links intracellular trafficking to organ morphogenesis in vivo, and presents a novel framework for decoding pancreatic development. HIGHLIGHTSO_LIRab11Af/f;Rab11B-/-;Pdx1-Cre pancreas displays disruption of epithelial organization and reduction of endocrine cell mass. C_LIO_LILoss of Rab11 results in disruption of pancreatic lumen continuity due to a failure of lumen formation. C_LIO_LIEpithelial cells lacking Rab11 display abnormal polarity. C_LI

developmental biology↗