Biology subjects

Axelrad, J.

Publications and source records attributed to Axelrad, J..

2 recordsLinked to original sources

bioRxiv2021

Intestinal organoids expose heterogeneity in SARS-CoV-2 susceptibility

Gastrointestinal effects associated with COVID-19 are highly variable for reasons that are not understood. In this study, we used intestinal organoid-derived cultures differentiated from primary human specimens as a model to examine inter-individual variability. Infection of intestinal organoids derived from different donors with SARS-CoV-2 resulted in orders of magnitude differences in virus replication in small intestinal and colonic organoid-derived monolayers. Susceptibility to infection correlated with ACE2 expression level and was independent of donor demographic or clinical features. ACE2 transcript levels in cell culture matched the amount of ACE2 in primary tissue indicating this feature of the intestinal epithelium is retained in the organoids. Longitudinal transcriptomics of organoid-derived monolayers identified a delayed yet robust interferon signature, the magnitude of which corresponded to the degree of SARS-CoV-2 infection. Interestingly, virus with the Omicron variant spike protein infected the organoids with the highest infectivity, suggesting increased tropism of the virus for intestinal tissue. These results suggest that heterogeneity in SARS-CoV-2 replication in intestinal tissues results from differences in ACE2 levels, which may underlie variable patient outcomes.

cell biology↗

bioRxiv2020

Transcriptional Atlas of Ileal-Anal Pouch Immune Cells from Ulcerative Colitis Patients

How the human intestinal immune system is distinctly organized to respond to inflammation is still poorly understood. Here, we used single-cell RNA-sequencing to examine lamina propria CD45+ hematopoietic cells from patients with inflammatory bowel disease that have undergone ileal pouch-anal anastomosis, or the colon mucosa of ulcerative colitis patients. We identified a population of IL1B+ antimicrobial macrophages and FOXP3/+BATF+ T cells that are associated and expanded in inflamed tissues, which we further validated in other scRNA-seq datasets from IBD patients. CD8+ T cells were unexpectedly more abundant in the pouch than colon. Cell type specific markers obtained from single-cell RNA-sequencing was used to infer representation from bulk RNA sequencing datasets, which further implicated antimicrobial macrophages expressing IL1B with S100A8/A9 calprotectin as being associated with inflammation, as well as Bacteroides and Escherichia bacterial species. Finally, we find that non-responsiveness to anti-integrin biologic therapies in UC patients is associated with the signature of this antimicrobial macrophage population in a subset of patients. This study identified conserved and distinct features of intestinal inflammation between parts of the small and large intestine undergoing similar inflammation conditions.

immunology↗