Dörr, D. | bioRxiv Science

bioRxiv2024

Arginine methylation of the p30 C/EBPα oncoprotein regulates progenitor proliferation and myeloid differentiation

The transcription factor CCAAT enhancer binding protein alpha (C/EBP) is a master regulator of myelopoiesis. CEBPA encodes a long (p42) and a truncated (p30) protein isoform from a single mRNA. Mutations that abnormally enhance expression of p30 are associated with acute myelogenous leukemia (AML). We show by mutational analysis that three highly conserved arginine residues (R140,147,154) located at the p30 C/EBP N-terminus, previously found to be methylated, are involved in myeloid lineage commitment, progenitor proliferation, and differentiation. Replacement with lysine that retains the amino acid side chain charge enhanced progenitor proliferation, while uncharged side chains (alanine or leucine) impaired proliferation and enhanced granulopoietic differentiation. Analysis of protein-protein interactions (PPI) suggested that arginine methylation of p30 C/EBP differentially determines its capacity to interact with SWI/SNF and MLL complexes. Pharmacological targeting of p30 C/EBP arginine methylation may have clinical relevance in myeloproliferative and inflammatory diseases, in neutropenia, and in leukemic stem cells.

cell biology↗

bioRxiv2022

Tongue immune compartment analysis reveals spatial macrophage heterogeneity

The tongue is a unique muscular organ situated in the oral cavity where it is involved in taste sensation, mastication and articulation. As a barrier organ, which is constantly exposed to environmental pathogens, the tongue is expected to host an immune cell network ensuring local immune defence. However, the composition and the transcriptional landscape of the tongue immune system are currently not completely defined. Here we characterised the tissue-resident immune compartment of the murine tongue during development, health and disease, combining single cell RNA-sequencing with in situ immunophenotyping. We identified distinct local immune cell populations and described two specific subsets of tongue-resident macrophages occupying discrete anatomical niches. Cx3cr1+ macrophages were located specifically in the highly innervated lamina propria beneath the tongue epidermis and at times in close proximity to fungiform papillae. Folr2+ macrophages were detected in deeper muscular tissue. The two macrophage subsets originate from a common proliferative precursor during early postnatal development and responded differently to systemic LPS in vivo. Our description of the under-investigated tongue immune system sets a starting point to facilitate research on tongue immune-physiology and pathology including cancer and taste disorders.

immunology↗