MicroRNA 181 Suppresses Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Infection by Targeting PRRSV Receptor CD163

Abstract

We previously showed that microRNA 181 (miR-181) can inhibit PRRSV replication by directly targeting its genomic RNA. Here, we report that miR-181 can downregulate the PRRSV receptor CD163 in blood monocytes and porcine alveolar macrophages (PAMs) through targeting the 3= untranslated region (UTR) of CD163 mRNA. Downregulation of CD163 leads to the inhibition of PRRSV entry into PAMs and subsequently suppresses PRRSV infection. Our findings indicate that delivery of miR-181 can be used as antiviral therapy against PRRSV infection. P orcine reproductive and respiratory syndrome (PRRS) is one of the most important diseases in swine industry worldwide. PRRS virus (PRRSV) is an ϳ15.4-kb positive-sense RNA virus belonging to the family Arteriviridae (1). Most recently, there have been devastating outbreaks in China of atypical PRRS, which is caused by a highly pathogenic PRRSV (HP-PRRSV) genotype (2). Currently, there are no effective ways to protect pigs from PRRSV infection (3).Studies have revealed that microRNAs (miRNAs) participate in host antiviral responses, either by targeting cellular factors essential for virus replications (4, 5) or by directly targeting virus genomes (6-8). We previously showed that in blood monocytes, which are refractory to PRRSV infection, the microRNA 181 (miR-181) expression level is 9 times higher than that in porcine alveolar macrophages (PAMs) (9). Given that blood monocytes do not express the PRRSV receptor CD163 or express it at very low levels, we propose that miR-181 might downregulate CD163 and subsequently inhibit PRRSV infection.To investigate whether miR-181 can target CD163, we first performed computational prediction analysis with RegRNA (10) to identify the potential target sites of miR-181 in CD163 mRNA. Three miR-181 seed binding sites were found, one in the 3= untranslated region (UTR) (3544 to 3565) and two in the coding region (623 to 644 and 842 to 863).PRRSV infection in cultured monocytes is coordinated well with the increased CD163 (11). Thus, we examined the relationship of CD163 and miR-181c expression in cultured monocytes in the presence of L929 cell culture supernatant (12-14). Our results showed that CD163 mRNA was significantly upregulated (about 14 times higher at 48 h than at 2 h) (Fig. 1A, left). Meanwhile, the miR-181c expression level decreased gradually and was more than 80% lower in abundance at 48 h than at 2 h (Fig. 1A, right). We also analyzed CD163 and miR-181c expression levels in cultured monocytes without L929 cell culture supernatants. As shown in Fig. 1B, increased CD163 expression was also coordinated with the reduced miR-181c expression. These results suggest that there might be an inverse correlation between the expressions of miR181c and CD163 during monocyte-macrophage differentiation. To further confirm this correlation, we transfected miR-181c mimics or negative-control (NC) mimics into 2-h-cultured monocytes and then detected CD163 mRNA expression using quantitative real-time PCR at different times. As shown in Fig. 1C, aberrant h...

MicroRNA-30c Modulates Type I IFN Responses To Facilitate Porcine Reproductive and Respiratory Syndrome Virus Infection by Targeting JAK1

“…In a previous study, we revealed that miR-181, an effective antiviral miRNA, is expressed at a much higher level in peritoneal macrophages than in PAMs, and the total level of miRNAs that potentially target PRRSV in peritoneal macrophages is also higher than that in PAMs (48,49). Interestingly, miR-30c, a proviral miRNA, is expressed at lower levels in peritoneal macrophages than in PAMs (Fig.…”

A brief review of microRNA and its role in PRRSV infection and replication

“…In a subsequent study [6], we found that in addition to directly targeting the PRRSV genome, miR-181 was also confirmed to suppress PRRSV infection by downregulating its receptor, CD163. A previous study showed that the enhanced susceptibility of cultured peripheral blood monocytes (BMo) to PRRSV is coordinated well with the increased CD163 expression [59].…”

“…Increasing evidence indicates that miRNAs can participate in the regulation of almost every cellular activity and their abnormal expression is associated with many human diseases. Recently, several studies have demonstrated that miRNAs can regulate PRRSV infection and replication [5][6][7][8]. Here we discuss the current understanding of the role of miRNA in PRRSV infection and hypothesize that cellular miRNAs may contribute significantly to regulating PRRSV infection.…”

MicroRNA miR-24-3p Promotes Porcine Reproductive and Respiratory Syndrome Virus Replication through Suppression of Heme Oxygenase-1 Expression

“…An RNA-induced silencing complex (RISC) immunoprecipitation assay was performed as previously described (27,37) with the following modifications. MARC-145 cells were seeded in a six-well plate at a density of 2 ϫ 10 5 cells/well.…”

“…Kaposi's sarcoma-associated herpesvirus upregulates miR-132 expression that, in turn, inhibits the expression of p300, a transcriptional coactivator, to promote viral replication (25). miR-125b reduces PRRSV replication by negatively regulating the NF-B pathway (26), and miR-181 inhibits PRRSV replication by targeting both viral genomic RNA and receptor CD163 (27,28).…”