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Cathelicidins have been shown to effectively inhibit flavivirus replication in vitro. However, the effects of mouse and human endogenous cathelicidins on flavivirus infection in vivo are rarely known. We herein found that mouse endogenous cathelicidin CRAMP was significantly up-regulated upon Zika virus (ZIKV) infection. CRAMP deficiency markedly exacerbated ZIKV replication in testis, and aggravated ZIKV-induced testicular damage and spermatic damage in mice, indicating that endogenous cathelicidin is required for protection against ZIKV-caused male infertility in mice. In vitro antiviral assay showed that both mouse cathelidin CRAMP and human cathelicidin LL-37 obviously reduced ZIKV-caused cytopathic effect and inhibited ZIKV replication in Vero cells. Antiviral mechanism revealed that they both directly inactivated ZIKV virons by binding to ZIKV virons and inducing the leakage of ZIKV genomic RNA, consequently inactivated ZIKV virons. In vivo antiviral assay indicated that both of them effectively inhibited ZIKV replication in C57BL/6J and IFNα/β receptor-deficient (Ifnar1

Coxsackievirus B3 (CVB3) infection can cause acute myocarditis and chronic myocarditis, leading to dilated cardiomyopathy (DCM) with no effective therapeutic strategy. Therefore, we investigated the potential of absent in melanoma 2 (AIM2) to enhance the therapeutic efficacy of DNA vaccine against CVB3-induced chronic myocarditis. Mice were infected with CVB3 and then intranasally immunized with chitosan-pcDNA3.1 (mock), chitosan-pAIM2 (CS-pAIM2), chitosan-pVP1 (CS-pVP1), or chitosan-pAIM2 plus chitosan-pVP1 (CS-pAIM2/CS-pVP1) at 7, 21, and 35 d. Therapeutic efficacies of various vaccines were evaluated at day 56 d. Compared with CS-pVP1 immunization, CS-pAIM2/CS-pVP1 co-immunization significantly increased survival rate, improved cardiac function, as well as decreased myocardial injury and fibrosis, this result indicated that CVB3-induced chronic myocarditis was alleviated. CVB3-specific T lymphocyte proliferation and cytotoxic T lymphocyte responses of the CS-pAIM2/CS-pVP1 co-immunization group were also increased. More interestingly, CS-pAIM2/CS-pVP1 co-immunization could facilitate CVB3-specific multifunctional CD8 + T cell induction in the intestinal mucosa, and this induction was closely correlated with myocardial scores, this result indicated that CS-pAIM2/CS-pVP1 vaccine exhibits therapeutic efficacy by enhancing multifunctional CD8 + T cells. This study may represent a novel therapy for CVB3-induced chronic myocarditis.

Chronic hepatitis B virus (HBV) infection causes liver cirrhosis and hepatocellular carcinoma and remains a serious health problem worldwide. Covalently closed circular DNA (cccDNA) in the liver cell nucleus sustains HBV infection. Major treatments for HBV infection include the use of interferon-α and nucleotide analogs, but they cannot eradicate cccDNA. As a novel tool for genome editing, clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system developed from bacteria can be used to accurately and efficiently engineer and modify genomic DNA. In this study, the CRISPR/Cas9 system was used to target the HBV genome and efficiently inhibit HBV infection. We synthesized four single-guide RNAs (sgRNAs) targeting the conserved regions of HBV. The expression of these sgRNAS with Cas9 reduced the viral production in Huh7 cells as well as in HBV-replication cell HepG2.2.15. We further demonstrated that CRISPR/Cas9 direct cleavage and cleavage-mediated mutagenesis occurred in HBV cccDNA of transfected cells. In the new mouse model carrying HBV cccDNA, injection of sgRNA–Cas9 plasmids via rapid tail vein resulted in the low level of cccDNA and HBV protein. In conclusion, the designed CRISPR/Cas9 system can accurately and efficiently target HBV cccDNA and inhibit HBV replication. This system may be used as a novel therapeutic strategy against chronic HBV infection.