Denise K Marciano | PubMed Health

PubMed2025

Zonal endothelial cell heterogeneity underlies murine renal vascular development.

The renal vasculature consists of highly specialized blood vessels with 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 the transcriptional heterogeneity of embryonic renal endothelial cells (ECs). We identified ten endothelial subtypes, and validated regionally restricted expression of novel marker genes of glomeruli, arteries, vasa recta, and immature capillary subtypes using multiplex RNAscope. We also define previously uncharacterized and heterogeneous molecular signatures of the immature renal vasculature, including putative endothelial progenitors. We interrogate biological characteristics of immature EC types using a variety of in vivo tools. Lineage tracing of Esm1-expressing cells reveals the previously unrecognized multi-origin and multi-clonal endothelial tip cell contribution to the glomerular vasculature. Together, this study provides a validated, tool-focused developmental atlas of the murine renal vasculature and elucidates novel cellular mechanisms of nephron vascularization.

Animals↗

PubMed2001

Assembling filamentous phage occlude pIV channels.

Filamentous phage f1 is exported from its Escherichia coli host without killing the bacterial cell. Phage-encoded protein pIV, which is required for phage assembly and secretion, forms large highly conductive channels in the outer membrane of E. coli. It has been proposed that the phage are extruded across the bacterial outer membrane through pIV channels. To test this prediction, we developed an in vivo assay by using a mutant pIV that functions in phage export but whose channel opens in the absence of phage extrusion. In E. coli lacking its native maltooligosacharride transporter LamB, this pIV variant allowed oligosaccharide transport across the outer membrane. This entry of oligosaccharide was decreased by phage production and still further decreased by production of phage that cannot be released from the cell surface. Thus, exiting phage block the pIV-dependent entry of oligosaccharide, suggesting that phage occupy the lumen of pIV channels. This study provides the first evidence, to our knowledge, for viral exit through a large aqueous channel.

Coliphages↗