ABSTRACT
Porcine epidemic diarrhea virus (PEDV) in the Coronavirus family is a highly contagious enteric pathogen in the swine industry, which has evolved mechanisms to evade host innate immune responses. The PEDV-mediated inhibition of interferons (IFNs) has been linked to the nuclear factor-kappa B (NF-κB) pathway. MicroRNAs (miRNAs) are involved in virus-host interactions and IFN-I regulation. However, the mechanism by which the PEDV regulates IFN during PEDV infection has not yet been investigated in its natural target cells. We here report a novel mechanism of viral immune escape involving miR-615, which was screened from a high-throughput sequencing library of porcine intestinal epithelial cells (IECs) infected with PEDV. PEDV infection altered the profiles of miRNAs and the activities of several pathways involved in innate immunity. Overexpression of miR-615 increased PEDV replication, inhibited IFN expression, downregulated the NF-κB pathway, and blocked p65 nuclear translocation. In contrast, knockdown of miR-615 enhanced IFN expression, suppressed PEDV replication, and activated the NF-κB pathway. We further determined that IRAK1 is the target gene of miR-615 in IECs. Our findings show that miR-615 suppresses activation of the NF-κB pathway by suppressing the IRAK1 protein and reducing the generation of IFN-IIIs, which in turn facilitates PEDV infection in IECs. Moreover, miR-615 inhibited PEDV replication and NF-κB pathway activation in both IECs and MARC-145 cells. These findings support an important role for miR-615 in the innate immune regulation of PEDV infections and provide a novel perspective for developing new treatments.
ABSTRACT
PURPOSE: Cisplatin-based neoadjuvant chemotherapy (NAC) has been shown to improve survival in patients with muscle-invasive bladder cancer (MIBC) who underwent radical cystectomy as compared with patients who underwent surgery alone. It has also been suggested as current standard of care in surgically-fit patients with MIBC. This meta-analysis assessed the effect of cisplatin-based NAC on survival in patients with bladder cancer. SOURCE: PubMed, CENTRAL, and Embase were searched until November 22, 2016. Two-arm randomized controlled trials that compared cisplatin-based neoadjuvant chemotherapy plus local treatment versus the same local treatment without neoadjuvant chemotherapy were selected. Patients with histologically-confirmed bladder cancer (adenocarcinoma, transitional, or squamous-cell carcinoma) were included. The primary outcome was overall survival (OS). PRINCIPAL FINDINGS: Of the 292 articles initially identified, 14 were included in the final analysis. Patients in the NAC group had similar OS as the local treatment (i.e., radiation therapy or cystectomy) group (pooled hazard ratio [HR] = 0.92, 95% confidence interval [CI]: 0.84 to 1.00, P=0.056). No difference in progress-free survival between two groups was observed (P=0.725). Subgroup analysis showed that OS was similar in patients treated with NAC plus radiotherapy or cystectomy compared with patients who received local treatment alone. CONCLUSIONS: Platinum-based NAC was associated with similar survival benefit as patients undergoing cystectomy and/or radiotherapy. No conclusion can be drawn about the optimal platinum-based combination to be used in the neoadjuvant setting.