A cis-acting ligase ribozyme generates circular RNA in vitro for ectopic protein functioning.

Delivering synthetic protein-coding RNA bypassing the DNA stage for ectopic protein functioning is a novel therapeutic strategy. Joining the linear RNA head-to-tail covalently could be a state-of-the-art strategy for functioning longer. Here we enroll a cis-acting ligase ribozyme (RzL) to generate circular RNA (circRNA) in vitro for ectopic protein expression. The RNA circularization is confirmed by masking the 5' phosphate group, resisting exonuclease RNase R digestion, failing for further tailing, and sequencing the RT-PCR products of the joined region. Interestingly, one internal ribosome entry site (IRES) renders circRNA translation competent, but two IRES in cis, not trans, hamper the translation. The circRNA with highly potent in translation is conferred for antiviral functioning. Accompanying specific guided RNA, a circRNA expressing ribonuclease Cas13 shows excellent potential against the corresponding RNA virus, further extending circRNA functioning in its growing list of applications.

Zika virus cleaves GSDMD to disseminate prognosticable and controllable oncolysis in a human glioblastoma cell model.

Glioblastoma (GBM) is the most common aggressive malignant brain cancer and is chemo- and radioresistant, with poor therapeutic outcomes. The "double-edged sword" of virus-induced cell death could be a potential solution if the oncolytic virus specifically kills cancer cells but spares normal ones. Zika virus (ZIKV) has been defined as a prospective oncolytic virus by selectively targeting GBM cells, but unclear understanding of how ZIKV kills GBM and the consequences hinders its application. Here, we found that the cellular gasdermin D (GSDMD) is required for the efficient death of a human GBM cell line caused by ZIKV infection. The ZIKV protease specifically cleaves human GSDMD to activate caspase-independent pyroptosis, harming both viral protease-harboring and naive neighboring cells. Analyzing human GSDMD variants showed that most people were susceptible to ZIKV-induced cytotoxicity, except for those with variants that resisted ZIKV cleavage or were defective in oligomerizing the N terminus GSDMD cleavage product. Consistently, ZIKV-induced secretion of the pro-inflammatory cytokine interleukin-1ß and cytolytic activity were both stopped by a small-molecule inhibitor targeting GSDMD oligomerization. Thus, potential ZIKV oncolytic therapy for GBM would depend on the patient's GSDMD genetic background and could be abolished by GSDMD inhibitors if required.