bioRxiv Science⌕ Search

Biology subjects

Shir, S.

Publications and source records attributed to Shir, S..

2 recordsLinked to original sources

Spatial Rewiring of Enterocyte Identity in Celiac Disease

Enterocytes in the human small intestine exhibit distinct functional states in different zones along the crypt-villus axis, a feature that is thought to convey optimal absorption. In celiac disease (CeD), autoimmune destruction of enterocytes leads to villus blunting, but how this altered tissue morphology affects enterocyte states is unclear. Using spatial and single-cell transcriptomics, we show that in patients with CeD, enterocytes acquire a novel identity characterized by co-expression of multiple zonal programs. This aberrant zonal co-expression results from reduced distances between BMP- and WNT-producing mesenchymal cells, leading to overlapping morphogen fields. In addition, we identify a subset of metaplastic cells that adopt gastric pit cell-like identities in discrete tissue patches. Our findings provide a detailed view of epithelial remodeling in CeD and establish a resource for understanding the cellular basis of malabsorption associated with villus blunting.

systems biology↗

TIR signaling activates caspase-like immunity in bacteria

Proteases of the caspase family, as well as Toll/Interleukin-1 Receptor (TIR)-domain proteins, have central roles in innate immunity and regulated cell death in humans. In this study we describe a bacterial immune system comprising both a caspase-like protease and a TIR-domain protein. We found that the TIR protein, once it recognizes phage invasion, produces the previously unknown immune signaling molecule ADP-cyclo[N7:1'']-ribose (N7-cADPR). This molecule specifically activates the bacterial caspase-like protease which then indiscriminately degrades cellular proteins to halt phage replication. The TIR-caspase defense system, which we denote as type IV Thoeris, is abundant in bacteria and efficiently protects against phage propagation. Our study highlights the diversity of TIR-produced immune signaling molecules and demonstrates that cell death regulated by proteases of the caspase family is an ancient mechanism of innate immunity.

microbiology↗