Oligoadenylate-Synthetase-Family Protein OASL Inhibits Activity of the DNA Sensor cGAS during DNA Virus Infection to Limit Interferon Production.

Interferon-inducible human oligoadenylate synthetase-like (OASL) and its mouse ortholog, Oasl2, enhance RNA-sensor RIG-I-mediated type I interferon (IFN) induction and inhibit RNA virus replication. Here, we show that OASL and Oasl2 have the opposite effect in the context of DNA virus infection. In Oasl2-/- mice and OASL-deficient human cells, DNA viruses such as vaccinia, herpes simplex, and adenovirus induced increased IFN production, which resulted in reduced virus replication and pathology. Correspondingly, ectopic expression of OASL in human cells inhibited IFN induction through the cGAS-STING DNA-sensing pathway. cGAS was necessary for the reduced DNA virus replication observed in OASL-deficient cells. OASL directly and specifically bound to cGAS independently of double-stranded DNA, resulting in a non-competitive inhibition of the second messenger cyclic GMP-AMP production. Our findings define distinct mechanisms by which OASL differentially regulates host IFN responses during RNA and DNA virus infection and identify OASL as a negative-feedback regulator of cGAS.

Oncolytic Viruses Engineered to Enforce Leptin Expression Reprogram Tumor-Infiltrating T Cell Metabolism and Promote Tumor Clearance.

Immunotherapy can reinvigorate dormant responses to cancer, but response rates remain low. Oncolytic viruses, which replicate in cancer cells, induce tumor lysis and immune priming, but their immune consequences are unclear. We profiled the infiltrate of aggressive melanomas induced by oncolytic Vaccinia virus using RNA sequencing and found substantial remodeling of the tumor microenvironment, dominated by effector T cell influx. However, responses to oncolytic viruses were incomplete due to metabolic insufficiencies induced by the tumor microenvironment. We identified the adipokine leptin as a potent metabolic reprogramming agent that supported antitumor responses. Leptin metabolically reprogrammed T cells in vitro, and melanoma cells expressing leptin were immunologically controlled in mice. Engineering oncolytic viruses to express leptin in tumor cells induced complete responses in tumor-bearing mice and supported memory development in the tumor infiltrate. Thus, leptin can provide metabolic support to tumor immunity, and oncolytic viruses represent a platform to deliver metabolic therapy.

Binding of ICP4, TATA-binding protein, and RNA polymerase II to herpes simplex virus type 1 immediate-early, early, and late promoters in virus-infected cells.

The binding of herpes simplex virus type 1 ICP4, TATA-binding protein (TBP), and RNA polymerase II (polII) to the promoter regions of representative immediate-early (IE) (ICP0), early (E) (thymidine kinase [tk]), and late (L) (glycoprotein C [gC]) genes on the viral genome was examined as a function of time postinfection, viral DNA replication, cis-acting sites for TFIID in the tk and gC promoters, and genetic background of ICP4. The binding of TBP and polII to the IE ICP0 promoter was independent of the presence of ICP4, whereas the binding of TBP and polII to the tk and gC promoters occurred only when ICP4 also bound to the promoters, suggesting that the presence of ICP4 at the promoters of E and L genes in virus-infected cells is crucial for the formation of transcription complexes on these promoters. When the TATA box of the tk promoter or the initiator element (INR) of the gC promoter was mutated, a reduction in the amount of TBP and polII binding was observed. However, a reduction in the amount of ICP4 binding to the promoters was also observed, suggesting that the binding of TBP-containing complexes and ICP4 is cooperative. The binding of ICP4, TBP, and polII was also observed on the gC promoter at early times postinfection or when DNA synthesis was inhibited, suggesting that transcription complexes may be formed early on L promoters and that additional events or proteins are required for expression. The ability to form these early complexes on the gC promoter required the DNA-binding domain but in addition required the carboxyl-terminal 524 amino acids of ICP4, which is missing the virus n208. This region was not required to form TBP- and polII-containing complexes on the tk promoter. n208 activates E but not L genes during viral infection. These data suggest that a region of ICP4 may differentiate between forming TBP- and polII-containing complexes on E and L promoters.

Influence of Terminalia chebula on dermal wound healing in rats.

The effects of topical administration of an alcohol extract of the leaves of an evergreen plant, Terminalia chebula, on the healing of rat dermal wounds, in vivo, was assessed. T. chebula treated wounds healed much faster as indicated by improved rates of contraction and a decreased period of epithelialization. Biochemical studies revealed a significant increase in total protein, DNA and collagen contents in the granulation tissues of treated wounds. The levels of hexosamine and uronic acid in these tissues, also increased upto day 8 post-wounding. Reduced lipid peroxide levels in treated wounds, as well as ESR measurement of antioxidant activity by DPPH radical quenching, suggested that T. chebula possessed antioxidant activities. The tensile strength of tissues from extract-treated incision wounds increased by about 40%. In addition, T. chebula possessed antimicrobial activity and was active largely against Staphylococcus aureus and Klebsiella. These results strongly document the beneficial effects of T. chebula in the acceleration of the healing process.