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Biology subjects

Stik, G.

Publications and source records attributed to Stik, G..

2 recordsLinked to original sources

TET2-driven activation of AGO2 links epigenetic remodeling to myeloid commitment and leukemia

DNA methylation dynamics shape hematopoietic differentiation and leukemogenesis; yet how the dioxygenase TET2--frequently mutated in myeloid malignancies--directs lineage-specific regulatory programs remains unclear. Here, we integrated DNA methylation, chromatin accessibility, 3D genome architecture, transcriptional profiling, and TET2 chromatin occupancy to define TET2-dependent control of human myeloid commitment. We found that TET2-bound regulatory regions gain short- and long-range chromatin interactions and that a distinct subset of distal, enhancer-enriched sites undergoes TET2-driven demethylation and activation. Among these, we identified an AGO2 myeloid-specific intragenic enhancer that is frequently hypermethylated in TET2-mutant AML patients. AGO2 expression stratifies patient survival, and AGO2 depletion abrogates leukemic engraftment in vivo. These findings uncover a TET2-AGO2 regulatory axis that integrates epigenetic remodeling, 3D genome reorganization, and leukemic fitness, and they highlight AGO2 as a potential biomarker and therapeutic target in myeloid leukemia.

genomics↗

CCR1 regulatory variants linked to pulmonary macrophage recruitment in severe COVID-19

Genome-wide association studies have identified 3p21.31 as the main risk locus for severe disease in COVID-19 patients, although underlying biological mechanisms remain elusive. We performed a comprehensive epigenomic dissection of the 3p21.31 locus, identifying a CTCF-dependent tissue-specific 3D regulatory chromatin hub that controls the activity of several tissue-homing chemokine receptor (CCR) genes in monocytes and macrophages. Risk SNPs colocalized with regulatory elements and were linked to increased expression of CCR1, CCR2 and CCR5 in monocytes and macrophages. As excessive organ infiltration of inflammatory monocytes and macrophages is a hallmark of severe COVID-19, our findings provide a rationale for the genetic association of 3p21.31 variants with elevated risk of hospitalization upon SARS-CoV-2 infection.

immunology↗