NCBI Summary:
microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]
General function
RNA processing
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Comment
Up-regulation of miR-326 regulates pro-inflammatory cytokines targeting TLR-4 in buffalo granulosa cells. Chaurasiya V et al. (2020) A genome-wide profiling of microRNA (miRNA) in endotoxin tolerant buffalo granulosa cells identified miR-326 amongst top-10 upregulated miRNAs. In this study, we have elucidated the role of miR-326 in granulosa cells in vitro. In-silico analysis revealed that miR-326 have binding site for 3'UTR of TLR-4 (Toll-like receptor 4). Transfection experiments showed that there was a significant inhibition of TLR-4 when miR-326 mimic was transfected to buffalo granulosa cells. Furthermore, when miR-326 transfected granulosa cells were exposed to LPS, followed by expression analysis of TLR-4 complex genes (TLR-4 and MyD88) and pro-inflammatory cytokines, we found a decreased expression of both TLR-4 complex and pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β). We also found that the expression of anti-inflammatory (IL-10) gene was upregulated. To the best of our knowledge, this is the first study that showed the regulation of TLR-4 using miR-326. The present findings on regulation of TLR-4 are important and would help in understanding innate immunity regulation under different patho-physiology.//////////////////