Long Noncoding RNA RP11-115N4.1Promotes Inflammatory Responses by Interacting with HNRNPH3 and Enhancing the Transcription of HSP70 in Unexplained Recurrent Spontaneous Abortion

RP11-115N4.1 was identified as the most differentially expressed lncRNA which was highly upregulated in peripheral blood of non-pregnant URSA patients (P = 3.63E-07, Fold change = 2.96),andthis dysregulation was further validated in approximately 26.7% additional patients (4/15). RP11-115N4.1 expression was detected in both lymphocytes and monocytes of human peripheral blood, andin vitro overexpression of RP11-115N4.1 decreased cell proliferation in K562 cellssignificantly. Furthermore, heat-shock HSP70 genes (HSPA1A and HSPA1B) were found to be significantly upregulated upon RP11-115N4.1 overexpression by transcriptome analysis (HSPA1A (P = 4.39E-08, Fold change = 4.17), HSPA1B (P = 2.26E-06, Fold change = 2.99)).RNApull down and RNA immunoprecipitation assay (RIP) analysis demonstrated that RP11-115N4.1 bound to HNRNPH3 protein directly, which in turn activateheat-shock proteins (HSP70) analyzed by protein-protein interaction and HNRNP` knockdown assays. Most importantly,the high expression of HSP70 was also verified in the serum of URSA patients and the supernatant of K562 cells with RP11-115N4.1 activation, andHSP70 in supernatant can exacerbate inflammatory responses in monocytes by inducing IL-6, IL-1β and TNF-α and inhibit the migration of trophoblast cells, which might associate with URSA. We profiled lncRNAs expression in peripheral blood from 5 non-pregnant URSA patients and 5 matched controls by lncRNA microarray analysis. Functions of URSA-associated lncRNAs were further investigated in vitro.