Efficient Targeted Delivery of Bifunctional Circular Aptamer-ASO Chimera to Suppress the SARS-CoV-2 Proliferation and Inflammation.

Inhibition of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and excessive inflammation is the current task in the prevention and treatment of corona vireus disease 2019 (COVID-19). Here, a dual-function circular aptamer-ASO chimera (circSApt-NASO) is designed to suppress SARS-CoV-2 replication and inflammation. The chemically unmodified circSApt-NASO exhibits high serum stability by artificial cyclization. It is also demonstrated that the SApt binding to spike protein enables the chimera to be efficiently delivered into the host cells expressing ACE2 along with the infection of SARS-CoV-2. Among them, the SApt potently inhibits spike-induced inflammation. The NASO targeting to silence N genes not only display robust anti-N-induced inflammatory activity, but also achieve efficient inhibition of SARS-CoV-2 replication. Overall, benefiting from the high stability of the cyclization, antispike aptamer-dependent, and viral infection-mediate targeted delivery, the circSApt-NASO displays robust potential against authentic SARS-CoV-2 and Omicron, providing a promising specific anti-inflammatory and antiproliferative reagent for therapeutic COVID-19.

Anti-tumor effect of PD-L1-targeting antagonistic aptamer-ASO delivery system with dual inhibitory function in immunotherapy.

Checkpoint inhibitor antibody therapy by blocking the interaction of surface programmed death-ligand 1(PD-L1) and programmed cell death protein 1(PD-1) has promising advantages in cancer immunotherapy. However, the response of many patients remains unsatisfactorily, suspected to be relevant to PD-L1 located in other cellular compartments and antibodies do not have access to the intracellular compartments. Herein, we identify a PD-L1-targeting DNA aptamer (PA9-1) with dual roles, including an antagonist and a delivery agent dependent on PD-L1 internalization. And we design the PD-L1-targeting antagonistic aptamer-ASO delivery system (PA9-1-ASO), with synergistic inhibitory PD-L1 activity involving the combination of blockade and silencing mechanisms. This chimera not only blocks PD-L1/PD-1 but also achieves targeted delivery of the conjugated ASO to reduce both surface PD-L1 and total PD-L1 expression. Compared with the single blockade, this chimera with the dual inhibitory function synergistically inhibits PD-L1 to amplify immunotherapeutic efficacy, providing a promising synergistic strategy for immunotherapy.

Coagulation factors VII, IX and X are effective antibacterial proteins against drug-resistant Gram-negative bacteria.

Infections caused by drug-resistant "superbugs" pose an urgent public health threat due to the lack of effective drugs; however, certain mammalian proteins with intrinsic antibacterial activity might be underappreciated. Here, we reveal an antibacterial property against Gram-negative bacteria for factors VII, IX and X, three proteins with well-established roles in initiation of the coagulation cascade. These factors exert antibacterial function via their light chains (LCs). Unlike many antibacterial agents that target cell metabolism or the cytoplasmic membrane, the LCs act by hydrolyzing the major components of bacterial outer membrane, lipopolysaccharides, which are crucial for the survival of Gram-negative bacteria. The LC of factor VII exhibits in vitro efficacy towards all Gram-negative bacteria tested, including extensively drug-resistant (XDR) pathogens, at nanomolar concentrations. It is also highly effective in combating XDR Pseudomonas aeruginosa and Acinetobacter baumannii infections in vivo. Through decoding a unique mechanism whereby factors VII, IX and X behave as antimicrobial proteins, this study advances our understanding of the coagulation system in host defense, and suggests that these factors may participate in the pathogenesis of coagulation disorder-related diseases such as sepsis via their dual functions in blood coagulation and resistance to infection. Furthermore, this study may offer new strategies for combating Gram-negative "superbugs".