Hirano, K.-i. | bioRxiv Science

bioRxiv2024

A single microRNA miR-195 rescues the arrested B cell development induced by EBF1 deficiency

Accumulated studies have reported that hematopoietic differentiation was primarily regulated by transcription factors. Early B cell factor 1 (EBF1) is an essential transcription factor for B lymphopoiesis. Contrary to the canonical notion, we found that a single miRNA, miRNA-195 (miR-195) transduction let EBF1 deficient hematopoietic progenitor cells (HPCs) express CD19, carry out V(D)J recombination and class switch recombination, which implied that B cell matured without EBF1. A part of the mechanism was caused by FOXO1 accumulation via inhibition of FOXO1 phosphorylation pathways in which targets of miR-195 are enriched. These results suggested that some miRNA transductions could function as alternatives to transcription factors.

immunology↗

bioRxiv2022

A novel fluorescently-labeled long-chain fatty acid analog for the study of fatty acid metabolism in cultured cells

123I-15-(p-iodophenyl)-(R,S)-methyl pentadecanoic acid (BMIPP) is a long-chain fatty acid (LCFA) analog developed to examine myocardial LCFA metabolism and has been used as a tracer for nuclear cardiology. However, its use is limited because of the specialized features of cardiac scintigraphy. In this study, a novel BMIPP-based probe was utilized, in which iodine-123 was replaced with a fluorescent compound, to extend the use of 123I-BMIPP to a wider variety of cells ex vivo. To confirm that this fluorescent LCFA analog (fluorescent BMPP) was imported into cells, fluorescence-activated cell sorting (FACS) analysis and fluorescent cell imaging were performed using cultured cells. The analysis showed that the import of fluorescent BMPP into the cells occurred in a concentration-dependent manner. This import into cells was inhibited by Sulfosuccinimidyl Oleate in a dose-dependent manner, which is an inhibitor of CD36, a well-known LCFA transporter, suggesting that fluorescent BMPP could be imported into cells via the same pathway as LCFA. FACS and cell imaging intensities of the cells importing fluorescent BMPP were attenuated after incubation in the non-Alexa680-BMPP medium. These results suggest that fluorescent BMPP can be transported into and from cells, reflecting the metabolism of LCFA. Fluorescently-labeled BMPP has the potential to be used as a probe for studying LCFA metabolism in various cells.

cell biology↗