Mir142, also known as microRNA-142, is a microRNA with important regulatory functions. The classical stem-loop structure of Mir142 encodes two mature microRNAs, miR142-5p and miR142-3p. It is abundant in hematopoietic cells and plays a role in hematopoietic cell lineage differentiation and immune response regulation [4].

In leukemia research, Mir142 loss-of-function mutations have been studied. In mouse models, Mir142 loss-of-function synergizes with IDH2R140Q mutation, unlocking IDH2R140-dependent leukemogenesis through antagonistic regulation of HOX genes [2]. Also, Mir142 loss-of-function mutations in acute myelogenous leukemia (AML) result in increased ASH1L protein expression, elevated HOXA gene expression, and enhanced myeloid potential of multipotent hematopoietic progenitors, promoting leukemogenesis [3]. In a mouse model of stroke, circular RNA Hectd1 (circHectd1) acts as an endogenous Mir142 sponge. Knockdown of circHectd1 expression reduces infarct areas and astrocyte activation, suggesting that the regulation of Mir142 by circHectd1 is involved in cerebral ischemia [1].

In conclusion, Mir142 is crucial for hematopoietic cell differentiation and immune response. Studies using gene knockout or conditional knockout mouse models have revealed its role in leukemogenesis and cerebral ischemia. These findings provide a better understanding of the biological functions of Mir142 and its potential as a therapeutic target in related diseases.

References:

1. Han, Bing, Zhang, Yuan, Zhang, Yanhong, Hu, Gang, Yao, Honghong. 2018. Novel insight into circular RNA HECTD1 in astrocyte activation via autophagy by targeting MIR142-TIPARP: implications for cerebral ischemic stroke. In Autophagy, 14, 1164-1184. doi:10.1080/15548627.2018.1458173. https://pubmed.ncbi.nlm.nih.gov/29938598/

2. Marshall, A, Kasturiarachchi, J, Datta, P, Enver, T, Nimmo, R. 2020. Mir142 loss unlocks IDH2R140-dependent leukemogenesis through antagonistic regulation of HOX genes. In Scientific reports, 10, 19390. doi:10.1038/s41598-020-76218-8. https://pubmed.ncbi.nlm.nih.gov/33173219/

3. Trissal, Maria C, Wong, Terrence N, Yao, Juo-Chin, Reddy, Pavan R, Link, Daniel C. 2018. MIR142 Loss-of-Function Mutations Derepress ASH1L to Increase HOXA Gene Expression and Promote Leukemogenesis. In Cancer research, 78, 3510-3521. doi:10.1158/0008-5472.CAN-17-3592. https://pubmed.ncbi.nlm.nih.gov/29724719/

4. Sharma, Salil. 2017. Immunomodulation: A definitive role of microRNA-142. In Developmental and comparative immunology, 77, 150-156. doi:10.1016/j.dci.2017.08.001. https://pubmed.ncbi.nlm.nih.gov/28801229/