Evaluation of circulating microRNAs in plasma from horses with peritonitis provide insights into miRNA patterns associated with systemic inflammation

Abstract of associated article:Non-strangulating intestinal infarctions (NSII) associated with Strongylus vulgaris infection and idiopathic peritonitis (IP) share similar clinical presentations but require different treatment approaches. Horses with NSII need surgical intervention, while idiopathic peritonitis cases can be treated with antimicrobials. A correct diagnosis is thus crucial, but because the two diseases overlap in clinicopathological features, differentiation is difficult in clinical practice. MicroRNAs (miRNAs) are non-coding RNAs, known to show detectable changes in tissue and circulation during disease. This study aimed to explore differences in plasma miRNA abundance between patients with NSII and IP. Plasma samples were collected from 43 horses, consisting of 21 with NSII and 22 with IP. A subset (n=12) was submitted for small RNA sequencing to screen for miRNAs differing between the groups. Next, a panel of nine miRNAs were selected for evaluation by quantitative real-time PCR (qPCR). This selection was based on the miRNA abundance in the sequencing data and evidence from literature. Small RNA sequencing detected 628 miRNAs in the blood samples, but no miRNAs were differentially abundant between the disease groups. This finding was confirmed by qPCR. We can, however, confirm previous studies in that the top abundant miRNAs in both groups included Eca-Mir-122-3p and Eca-Mir-486-5p. Eca-Mir-223-3p was, likewise, in the top ten most abundant miRNAs, suggestive of general inflammation. The clinicopathological parameters evaluated showed differences between the groups similar to findings in previous studies. The results in this study show that NSII and idiopathic peritonitis elicit strikingly similar miRNA profiles in plasma, which is characterized by systemic inflammation.Experimental design of associated article:Plasma samples were collected from 43 horses, consisting of 21 with non-strangulating intestinal infarctions and 22 with idiopathic peritonitis. A subset (n=12) was submitted for small RNA sequencing to screen for miRNAs differing between the groups. A panel of nine miRNAs were selected for evaluation by quantitative real-time PCR (qPCR). This selection was based on the miRNA abundance in the sequencing data and evidence from literature. Target prediction and enrichement analysis was conducted to explore biological functions of the most abundant miRNAs.This BioProject contains small RNA-seq samples from the 12 horse plasma samples.