Levine-Ritterman, M. | bioRxiv Science

bioRxiv2020

Tet2 Controls Beta cells Responses to Inflammation in Type 1 Diabetes

{beta} cells may participate and contribute to their own demise during Type 1 diabetes (T1D). We identified a novel role of Tet2 in regulating immune killing of {beta} cells. Tet2 is induced in murine and human {beta} cells with inflammation but its expression is reduced in surviving {beta} cells. Tet2-KO mice that receive WT bone marrow transplants develop insulitis but not diabetes and islet infiltrates do not eliminate {beta} cells even though immune cells from the mice can transfer diabetes to NOD/scid recipients. Tet2-KO {beta} cells show reduced expression of inflammatory genes, associated with closed transcription factor binding sites. Tet2-KO recipients are protected from transfer of disease by diabetogenic immune cells. We conclude that Tet2 regulates pathologic interactions between {beta} cells and immune cells and controls intrinsic protective pathways. Modulating TET2 may enable survival of {beta} cells or their replacements in the setting of pathologic immune cells.

immunology↗

bioRxiv2019

The landscape of myeloid and astrocyte phenotypes in acute multiple sclerosis lesions

Activated myeloid cells and astrocytes are the predominant cell types in active multiple sclerosis (MS) lesions. Both cell types can adopt diverse functional states that play critical roles in lesion formation and resolution. In order to identify phenotypic subsets of myeloid cells and astrocytes, we profiled acute MS lesions with thirteen glial activation markers using imaging mass cytometry (IMC), a method for multiplexed labeling of histological sections. In a demyelinating lesion, we found multiple distinct myeloid and astrocyte phenotypes that populated separate lesion zones. In a post-demyelinating lesion, phenotypes were less distinct and more uniformly distributed. In both lesions cell-to-cell interactions were not random, but occurred between specific glial subpopulations and lymphocytes. Finally, we demonstrated that myeloid, but not astrocyte phenotypes were activated along a lesion rim-to-center gradient, and that marker expression in glial cells at the lesion rim was driven more by cell-extrinsic factors than in cells at the center. This proof-of-concept study demonstrates that highly multiplexed tissue imaging, combined with the appropriate computational tools, is a powerful approach to study heterogeneity, spatial distribution and cellular interactions in the context of MS lesions. Identifying glial phenotypes and their interactions at different lesion stages may provide novel therapeutic targets for inhibiting acute demyelination and low-grade, chronic inflammation.

immunology↗