ISGylation enhances dsRNA-induced interferon response and NFκB signaling in fallopian tube epithelial cells

Discovery of indole derivatives as STING degraders

Aberrant activation of the stimulator of interferon genes (STING) pathway is associated with the development of various inflammatory and autoimmune diseases. Targeting STING for degradation represents a novel strategy for the treatment of these diseases. In this study, we designed and synthesized a series of STING-PROTACs based on a nitro-free covalent warhead and different E3 ligase binders. The representative compound 2h specifically degraded STING protein through the proteasome pathway with a DC50 value of 3.23 μM and exhibited sustained degradation activity over 72 h. Further biological studies demonstrated that compound 2h inhibited STING signaling and effectively suppressed immune-inflammatory cytokines both in vitro and in vivo. Moreover, compound 2h offered better safety compared to its warhead molecule and SP23. Collectively, compound 2h is a potent nitro-free covalent STING degrader and warrants further investigation.

cGAS/STING signaling pathway in gynecological malignancies: From molecular mechanisms to therapeutic values

Gynecological cancers, including cervical, ovarian, and endometrial malignancies, remain a significant global health burden, exacerbated by disparities in access to preventive measures such as HPV vaccination and routine screening. The cGAS/STING signaling pathway, a pivotal mechanism in innate immunity, detects cytosolic DNA from pathogens or cellular damage, triggering immune responses via type I interferons and inflammatory cytokines. This pathway's dual role in gynecological cancers, either promoting antitumor immunity or facilitating tumor immune evasion, makes it a compelling target for innovative therapies. The article outlines cGAS/STING's influence on tumor microenvironments, immune surveillance, and inflammation, with emphasis on molecular mechanisms driving cancer progression. It explores interactions between DNA damage response pathways and immune modulation, highlighting the impact of cGAS/STING activation or suppression in ovarian, cervical, and endometrial cancers. The therapeutic potential of STING agonists, PARP inhibitors, and targeted immunotherapies is reviewed, demonstrating how these approaches can boost immune responses, counteract chemotherapy resistance, and improve patient outcomes. The study also discusses strategies for leveraging cGAS/STING signaling to enhance the efficacy of immunotherapies and address tumor-mediated immune suppression, providing insights into future directions for personalized cancer treatments.

Regulating Immune Responses Induced by PEGylated Messenger RNA-Lipid Nanoparticle Vaccine

Messenger RNA (mRNA)-based therapeutics have shown remarkable progress in the treatment and prevention of diseases. Lipid nanoparticles (LNPs) have shown great successes in delivering mRNAs. After an mRNA-LNP vaccine enters a cell via an endosome, mRNA is translated into an antigen, which can activate adaptive immunity. mRNAs can bind to various pattern recognition receptors (PRRs), including toll-like receptors (TLRs), and increase the production of inflammatory cytokines. This review summarizes mechanisms of innate immunity induced by mRNAs. Polyethylene glycol (PEG) has been employed as a component of the mRNA-LNP vaccine. PEGylated nanoparticles display enhanced stability by preventing aggregation of particles. However, PEGylation can cause adverse reactions, including blood clearance (ABC) of nanoparticles via complement activation and anaphylaxis. Mechanisms of PEG-induced ABC phenomenon and anaphylaxis are presented and discussed. There have been studies aimed at reducing immune responses associated with PEG to make safe and effective vaccines. Effects of modifying or replacing PEG in reducing immune responses associated with PEGylated nanoparticles are also discussed. Modifying mRNA can induce immune tolerance, which can prevent hypersensitivity reactions induced by PEGylated mRNA-LNP vaccines. Current progress of immune tolerance induction in association with mRNA-LNP is also summarized. This review might be helpful for developing safe and effective PEGylated mRNA-LNP vaccines.