Characterizing light-regulated retinal microRNAs reveals rapid turnover as a common property of neuronal microRNAs.

Adaptation to different levels of illumination is central to the function of the retina. Here, we demonstrate that levels of the miR-183/96/182 cluster, miR-204, and miR-211 are regulated by different light levels in the mouse retina. Concentrations of these microRNAs were downregulated during dark adaptation and upregulated in light-adapted retinas, with rapid decay and increased transcription being responsible for the respective changes.

Decreased levels of microRNA miR-122 in individuals with hepatitis C responding poorly to interferon therapy.

Several microRNAs (miRNAs), including liver-specific miR-122, have been implicated in the control of hepatitis C virus (HCV) RNA replication and its response to interferon (IFN) in human hepatoma cells. Our analysis of liver biopsies from subjects with chronic hepatitis C (CHC) undergoing IFN therapy revealed no correlation of miR-122 expression with viral load and markedly decreased pretreatment miR-122 levels in subjects who had no virological response during later IFN therapy; other investigated miRNAs showed only limited changes. These data have implications for the prospect of targeting miRNAs for CHC therapy.