AUTHOR=Liu Meilan , Sun Xiaoyue , Zhu Liqiong , Zhu Menglan , Deng Kewen , Nie Xiaolu , Mo Hanjie , Du Tao , Huang Bingqian , Hu Lihao , Liang Liuhong , Wang Dongyan , Luo Yinger , Yi Jinling , Zhang Jianping , Zhong Xingming , Cao Chunwei , Chen Hui 

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

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.717785

DOI=10.3389/fimmu.2021.717785

ISSN=1664-3224

ABSTRACT=<sec><title>Background</title><p>Unexplained recurrent spontaneous abortion (URSA) is a common pregnancy complication and the etiology is unknown. URSA-associated lncRNAs are expected to be potential biomarkers for diagnosis, and might be related to the disease pathogenesis.</p></sec><sec><title>Objective</title><p>To investigate differential lncRNAs in peripheral blood of non-pregnant URSA patients and matched healthy control women and to explore the possible mechanism of differential lncRNAs leading to URSA.</p></sec><sec><title>Methods</title><p>We profiled lncRNAs expression in peripheral blood from 5 non-pregnant URSA patients and 5 matched healthy control women by lncRNA microarray analysis. Functions of URSA-associated lncRNAs were further investigated <italic>in vitro</italic>.</p></sec><sec><title>Results</title><p>RP11-115N4.1 was identified as the most differentially expressed lncRNA which was highly upregulated in peripheral blood of non-pregnant URSA patients (<italic>P</italic> = 3.63E-07, Fold change = 2.96), and this dysregulation was further validated in approximately 26.67% additional patients (4/15). RP11-115N4.1 expression was detected in both lymphocytes and monocytes of human peripheral blood, and <italic>in vitro</italic> overexpression of RP11-115N4.1 decreased cell proliferation in K562 cells significantly. Furthermore, heat-shock HSP70 genes (<italic>HSPA1A</italic> and <italic>HSPA1B</italic>) were found to be significantly upregulated upon RP11-115N4.1 overexpression by transcriptome analysis (<italic>HSPA1A</italic> (<italic>P</italic> = 4.39E-08, Fold change = 4.17), <italic>HSPA1B</italic> (<italic>P</italic> = 2.26E-06, Fold change = 2.99)). RNA pull down and RNA immunoprecipitation assay (RIP) analysis demonstrated that RP11-115N4.1 bound to HNRNPH3 protein directly, which in turn activate heat-shock proteins (HSP70) analyzed by protein-protein interaction and <italic>HNRNPH3</italic> 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, and HSP70 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.</p></sec><sec><title>Conclusion</title><p>Our results demonstrated that the activation of RP11-115N4.1 can significantly increase the protein level of HSP70 <italic>via</italic> binding to HNRNPH3, which may modulate the immune responses and related to URSA. Moreover, RP11-115N4.1 may be a novel etiological biomarker and a new therapeutic target for URSA.</p></sec>