Glycyrrhizin is a natural component extracted from the roots of Glycyrrhiza glabra. In this study, we investigated the antiviral activity of glycyrrhizin against porcine reproductive and respiratory syndrome virus (PRRSV), an Arterivirus that has been devastating the swine industry worldwide since the late 1980s. Our results showed that treatment with glycyrrhizin significantly reduced PRRSV proliferation and PRRSV-encoded protein expression in a dose-dependent manner. Mechanistically, glycyrrhizin mainly inhibits the penetration stage, and has little effect on the steps of adsorption or release of PRRSV in its life cycle. Furthermore, we were able to exclude a direct inhibitory action of glycyrrhizin on PRRSV particles. Given these results, glycyrrhizin may be a candidate component for a novel porcine reproductive and respiratory syndrome (PRRS) control strategy.

Porcine deltacoronavirus (PDCoV), an emerging animal coronavirus causing enteric disease in pigs, belongs to the newly identified Deltacoronavirus genus in the Coronaviridae family. Although extensive studies have been carried out to investigate the regulation of interferon (IFN) responses by alphacoronaviruses, betacoronaviruses, and gammacoronaviruses, little is known about this process during deltacoronavirus infection. In this study, we found that PDCoV infection fails to induce, and even remarkably inhibits, Sendai virus- or poly(I: C)-induced IFN-β production by impeding the activation of transcription factors NF-κB and IRF3. We also found that PDCoV infection significantly suppresses the activation of IFN-β promoter stimulated by IRF3 or its upstream molecules (RIG-I, MDA5, IPS-1, TBK1, IKKε) in the RIG-I signaling pathway, but does not counteract its activation by the constitutively active mutant of IRF3 (IRF3-5D). Taken together, our results demonstrate that PDCoV infection suppresses RIG-I-mediated IFN signaling pathway, providing a better understanding of the PDCoV immune evasion strategy.

Ocular ischemic syndrome (OIS) is a severe ocular disease caused by ocular hypoperfusion due to stenosis or occlusion of the common or internal carotid arteries. OIS is easily misdiagnosed or undiagnosed given its asymptomatic onset and complicated ocular manifestations. The present study reviewed 42 patients with OIS, including 30 males (71.43%), 29 older patients (69.05%, >61 yrs), and 35 patients (83.33%) with two or more systemic diseases. Only 6 patients had ocular symptoms as the initial signs upon visiting the Department of Ophthalmology of three hospitals (the First Affiliated Hospital, Sun Yat-sen University; Zhongshan Ophthalmic Center, Sun Yat-sen University; and the Second Affiliated Hospital, Guangzhou Medical University). The ocular symptoms varied from visual deterioration to periorbital pain. Thirty-seven patients (88.10%) complained of constitutional symptoms. Ocular manifestations were diverse and involved both anterior and posterior segments. We reported a case of corneal edema and corneal epithelium erosion in the ipsilateral eye due to internal carotid artery stenosis. As the clinical manifestations of OIS are complex, ophthalmologists must carefully examine patients to avoid a misdiagnosis or a failure to diagnose. The management of OIS requires cooperation with cardiologists and neurologists.