Ultra-deep sequencing reveals the microRNA expression pattern of the human stomach.. Homo sapiens

Little is known about the miRNA expression levels in stomach tissue even though miRNAs play important roles in tissue differentiation and in maintaining basal physiology. Alterations in the miRNA profile lead to cell deregulation, which can induce neoplasia. This study aimed to characterize the normal miRNA profile of human gastric tissue to establish a reference profile for healthy individuals. A small RNA library of stomach tissue was sequenced using high-throughput SOLiD sequencing technology. We obtained 422,197 quality reads with perfect matches to the human miRnome, and 52% of known microRNAs were identified. Expression profiling was performed based on read abundance. Fifteen miRNAs were highly expressed in gastric tissue, and four seemed to be tissue-specific. Mir-148a, mir-192 and the mir-200 cluster (a and b) were highly expressed and could be considered biomarkers of gastric tissue. MiR-192 was identified in other normal human digestive tissue, and its high expression could act as a regulator of basal physiology in stomach tissue. MiR-148a and miR-200 (a and b) are specific to endocrine tissue and may be important in maintaining the integrity of endocrine tissues, such as the stomach. Deciphering the regulatory processes acting in the stomach will be important in the fight against gastric cancer, which is the second-leading cause of mortality in the world.