Malenica, Ivana

Extracellular RNAs (exRNAs) have been identified in all tested biofluids and have been associated with a variety of extracellular vesicles, ribonucleoprotein complexes and lipoprotein complexes. Much of the interest in exRNAs lies in the fact that they may serve as signalling molecules between cells, their potential to serve as biomarkers for prediction and diagnosis of disease and the possibility that exRNAs or the extracellular particles that carry them might be used for therapeutic purposes. Among the most significant bottlenecks to progress in this field is the lack of robust and standardized methods for collection and processing of biofluids, separation of different types of exRNA‐containing particles and isolation and analysis of exRNAs. The Sample and Assay Standards Working Group of the Extracellular RNA Communication Consortium is a group of laboratories funded by the U.S. National Institutes of Health to develop such methods. In our first joint endeavour, we held a series of conference calls and in‐person meetings to survey the methods used among our members, placed them in the context of the current literature and used our findings to identify areas in which the identification of robust methodologies would promote rapid advancements in the exRNA field.

Abstract Background & Aims Accumulating evidence indicates that micro RNA s play a role in a number of disease processes including the pathogenesis of liver fibrosis in hepatitis C infection. Our goal is to add to the accruing information regarding micro RNA deregulation in liver fibrosis to increase our understanding of the underlying mechanisms of pathology and progression. Methods We used next generation sequencing to profile all detectable micro RNA s in liver tissue and serum from patients with hepatitis C, stages F1–F4 of fibrosis. Results We found altered expression of several micro RNA s, in particular, miR‐182, miR199a‐5p, miR‐200a‐5p and miR‐183 were found to be significantly upregulated in tissue from liver biopsies of hepatitis C patients with advanced fibrosis, stage F3 and F4, when compared with liver biopsies from patients with early fibrosis, stages F1 and F2. We also found miR‐148‐5p, miR‐1260b, miR‐122‐3p and miR‐378i among the micro RNA s most significantly down‐regulated from early to advanced fibrosis of the liver. We also sequenced the serum micro RNA s; however, we were not able to detect significant changes in circulating micro RNA s associated with fibrosis stage after adjusting for multiple tests. Conclusions Adding measurements of tissue micro RNA s acquired during routine biopsies will continue to increase our knowledge of underlying mechanisms of fibrosis. Our goal is that these data, in combination with studies from other researchers and future long‐term studies, could be used to enhance the staging accuracy of liver biopsies and expand the surveillance of patients at increased risk for cancer and progression to advanced fibrosis.