Requirement of bic/microRNA-155 for Normal Immune Function

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.

RNA Profiling in Human and Murine Transplanted Hearts: Identification and Validation of Therapeutic Targets for Acute Cardiac and Renal Allograft Rejection

“…We observed perinuclear miR‐155 staining in pericardial inflammatory patches and infiltrating cells, whereas we did not detect any signal in adjacent cardiomyocytes (Figure 2H). These findings are in line with previous studies showing miR‐155 upregulation in leukocytes following activation 16, 18, 23.…”

“…Macrophage activation and dendritic cell maturation require its upregulation 16, 25, 28. Furthermore, miR‐155 functions at the interface of innate and adaptive immunity as miR‐155 deficient dendritic cells are unable to mount appropriate B and T cell responses 14, 16, 23.…”

“…Eight to ten‐week old BALB/cJ (Janvier), C57Bl/6J (Janvier), bic m2/m2 (miR155−/−) and WT littermates (miR155+/+) were subjected to cervical heterotopic HTX and sham operations 15, 16.…”

Hypoxia and chronic lung disease

“…Although the investigation of hypoxic MIRs has been restricted to screenings in cell cultures and in silico comparison with tumor data sets [4], the list of MIRs present in the hypoxic lung has not been compiled thus far. Nevertheless, the first evidence that MIRs may participate in lung diseases was provided by the report that MIR-155 might regulate inflammatory cell responses, such as in asthma [7].…”

Altered expression of MicroRNA in synovial fibroblasts and synovial tissue in rheumatoid arthritis

“…Initially, miR-155 was characterized as an oncogenic miRNA and was shown to be dysregulated in a large number of human neoplastic diseases (16). Subsequently, miR-155 was shown to be involved in the modulation of hematopoiesis, and very recently, its importance in the normal function of the immune system has been demonstrated (17)(18)(19).…”