Requirement of <i>bic/microRNA-155</i> for Normal Immune Function

TLDR

MicroRNAs are small RNAs that regulate gene expression, yet their physiological roles in mammals remain largely unexplored. The study investigates whether bic/microRNA‑155 is required for normal B‑cell, T‑cell, and dendritic‑cell function. Transcriptome profiling of bic/microRNA‑155‑deficient CD4⁺ T cells revealed widespread dysregulation of cytokine, chemokine, and transcription‑factor genes. Loss of bic/microRNA‑155 leads to immunodeficiency, heightened airway remodeling, and underscores its essential role in immune homeostasis.

Abstract

MicroRNAs are a class of small RNAs that are increasingly being recognized as important regulators of gene expression. Although hundreds of microRNAs are present in the mammalian genome, genetic studies addressing their physiological roles are at an early stage. We have shown that mice deficient for bic/microRNA-155 are immunodeficient and display increased lung airway remodeling. We demonstrate a requirement of bic/microRNA-155 for the function of B and T lymphocytes and dendritic cells. Transcriptome analysis of bic/microRNA-155-deficient CD4+ T cells identified a wide spectrum of microRNA-155-regulated genes, including cytokines, chemokines, and transcription factors. Our work suggests that bic/microRNA-155 plays a key role in the homeostasis and function of the immune system.