Long noncoding RNAs and their complex role in shaping and regulating arachidonic acid metabolism: Learning to love the (not-really) junk.

Long noncoding RNAs (lncRNAs) have emerged as critical regulators in numerous biological processes. The arachidonic acid (AA) metabolic pathway is a fundamental biochemical pathway responsible for the enzymatic conversion of AA, a 20-carbon omega-six polyunsaturated fatty acid, into a variety of potent lipid signaling molecules known as eicosanoids. Eicosanoids are produced through the cyclooxygenase and lipoxygenase arms of the AA pathway and have diverse biological roles in both healthy and disease states, including cancer and inflammatory diseases. Cyclooxygenase 2 (COX-2), the inducible, rate-limiting enzyme of the cyclooxygenase arm, produces two main forms of eicosanoids: prostaglandins and thromboxanes. AA  metabolized through the lipoxygenase arm by the action of 5-lipoxygenase (ALOX5) produces eicosanoids known as leukotrienes. COX-2 and ALOX5 gene expression are regulated through many different lncRNAs and microRNA (miRNA)-mediated mechanisms. As previously reviewed, noncoding RNAs affect transcription, splicing, alternative polyadenylation, messenger RNA stability, translation, and miRNA regulation of COX-2 and ALOX5 (Lutz and Cornett, 2013, Wiley Interdisciplinary Reviews. RNA, 4(5), 593-605). This current review discusses the intricate roles of lncRNAs, including MALAT1, NEAT1, HOTAIR, PACER, and others, in modulating the AA pathway. In this review update, we will delve into advancements in our understanding of AA gene expression regulation. We will explore the mechanisms of lncRNAs and their associated miRNAs and proteins known to regulate key components of the AA signaling pathway. We will also discuss the therapeutic potential of targeting lncRNA-mediated regulation, with a focus on modulating COX-2 and ALOX5 activity and downstream eicosanoid production for applications in inflammatory and oncological conditions. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA in Disease and Development > RNA in Disease.