Fangchinoline induces antiviral response by suppressing STING degradation

The stimulator of interferon genes(STING),an integral adaptor protein in the DNA-sensing pathway,plays a pivotal role in the innate immune response against infections.Additionally,it presents a valuable therapeutic target for infectious diseases and cancer.We observed that fangchinoline(Fan),a bis-benzylisoquinoline alkaloid(BBA),effectively impedes the replication of vesicular stomatitis virus(VSV),encephalomyocarditis virus(EMCV),influenza A virus(H1N1),and herpes simplex virus-1(HSV-1)in vitro.Fan treatment significantly reduced the viral load,attenuated tissue inflammation,and improved survival in a viral sepsis mouse model.Mechanistically,Fan activates the antiviral response in a STING-dependent manner,leading to increased expression of interferon(IFN)and interferon-stimulated genes(ISGs)for potent antiviral effects in vivo and in vitro.Notably,Fan interacts with STING,preventing its degradation and thereby extending the activation of IFN-based antiviral responses.Collectively,our findings highlight the potential of Fan,which elicits antiviral immunity by suppressing STING degradation,as a promising candidate for antiviral therapy.

Advances in the prerequisite and consequence of STING downstream signalosomes

The cyclic GMP-AMP synthase(cGAS)-stimulator of interferon genes(STING)pathway is an evolving DNA-sensing mechanism involved in innate immunity and pathogen defense that has been optimized while remaining conserved.Aside from recognizing pathogens through conserved motifs,these receptors also detect aberrant or misplaced self-molecules as possible signs of perturbed homeostasis.Upon binding external or self-derived DNA,a mobile sec-ondary messenger 2′3′-cyclic GMP-AMP(cGAMP)is produced by cGAS and in turn activates its adapter STING in the endo-plasmic reticulum(ER).Resting-state or activated STING protein isfinely restricted by multiple degradation machin-eries.The post-translational changes of the STING protein,along with the regulatory machinery ofthe secret routes,limit the onset,strength and sustention of STING signal.STING experiences a conformational shift and relocates with TBK1 from the ER to perinuclear vesicles containing transcription factors,provoking the transcription activity of IRF3/IFN-I and NF-κB pathways,as well as to initiate a number of cellular processes that have been shown to alter the immune landscape in cancer,such as autophagy,NLRP3 inflamma-some,ER stress,and cell death.STING signal thus serves as a potent activator for immune mobilization yet also triggers immune-mediated pathology in tissues.Recent advances have established the vital role of STING in immune surveil-lance as well as tumorigenic process.This review provides an overview of the disparate outcomes of cancer attributed to the actions of pleiotropic and coordinated STING downstream signalosomes,along with the underlying mechanisms of STING function in pathologies,providing therapeutic impli-cations for new approaches in hunt for the next generation of cancer immunotherapy base on STING.

Novel STING-targeted PET radiotracer for alert and therapeutic evaluation of acute lung injury

Acute lung injury(ALI),as a common clinical emergency,is pulmonary edema and diffuse lung infiltration caused by inflammation.The lack of non-invasive alert strategy,resulting in failure to carry out preventive treatment,means high mortality and poor prognosis.Stimulator of interferon genes(STING)is a key molecular biomarker of innate immunity in response to inflammation,but there is still a lack of STING-targeted strategy.In this study,a novel STING-targeted PET tracer,[~(18)F]FBTA,was labeled with high radiochemical yield(79.7±4.3%)and molar activity(32.5±2.9 GBq/μmol).We confirmed that[~(18)F]FBTA has a strong STING binding affinity(K_d=26.86±6.79 nmol/L)and can be used for PET imaging in ALI mice to alert early lung inflammation and to assess the efficacy of drug therapy.Our STING-targeted strategy also reveals that[~(18)F]FBTA can trace ALI before reaching the computed tomography(CT)diagnostic criteria,and demonstrates its better specificity and distribution than[~(18)F]fluorodeoxyglucose([~(18)F]FDG).

Update on the STING Signaling Pathway in Developing Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease(NAFLD)is a prevalent chronic liver condition with limited treatment options.Inflammation caused by metabolic disturbances plays a significant role in NAFLD development.Stimulator of interferon gene(STING),a critical regulator of innate immunity,induces the production of interferons and other pro-inflammatory factors by recognizing cytoplasmic DNA to defend against pathogen infection.The STING-mediated signaling pathway appears to play a vital role in hepatic inflammation,metabolic disorders,and even carcinogenesis.Promisingly,pharmacological interventions targeting STING have shown improvements in the pathological state of NAFLD.Macrophages,dendritic cells,natural killer cells,and T cell pathways regulated by STING present potential novel druggable targets for NAFLD treatment.Further research and development in this area may offer new therapeutic options for managing NAFLD effectively.

A prodrug nanoplatform via esterification of STING agonist and IDO inhibitor for synergistic cancer immunotherapy

Cancer immunotherapy has made significant progress in the last few decades,revolutionizing oncology.However,low patient response rates and potential immune-related adverse events continue to be major clinical challenges.Cancer nanomedicine,by virtue of its regulated delivery and modular flexibility,has shown the potential to strengthen antitumor immune responses and sensitize tumors to immunotherapy.In this study,we developed tumor microenvironment(TME)responsive nanomedicine to achieve specific and localized amplification of the immune response in tumor tissue in a safe and effective manner,while simultaneously reducing immune-related side effects.We synthesized the TME responsive prodrug by coupling MSA-2,a stimulator of interferon genes(STING)agonist,and NLG-919,an indoleamine 2,3 dioxygenase(IDO)inhibitor.The prodrug was assembled into nanoparticles to enhance the solubility and bioavailability.By synthesizing a TME responsive prodrug,we aim to explore the therapeutic efficacy of combined regimen(STING agonist and IDO inhibitor)for cancer,and reduce the unwanted side effects of STING agonism on normal tissues.Free prodrug and nanoparticles were characterized by mass spectrometry,dynamic light scattering(DLS),and transmission electron microscopy(TEM).Following that,we investigated the tumor accumulation,anti-tumor activity,and toxicity in vitro and in vivo.Prodrug nanoparticles demonstrated the ability to inhibit the tumor growth and activate antitumor immune response by modulating immune cells populations in tumor microenvironment.The TME responsive nanomedicine provided an effective tool for precise targeting,promoting antitumor immunity,and efficient tumor growth inhibition with safety.Outcomes of this study may have implications for future clinical trials.

The multifaceted functions of cGAS

Pattern recognition receptors arecritical forthe sensing of pathogen-associated molecular patterns or danger-associated molecular patterns and subsequent mounting of innate immunityandshaping ofadaptive immunity.The identification of 2'3'-cyclic guanosine monophosphate-adenosine monophosphate(cGAMP)synthase(cGAS)as a major cytosolic DNA receptor is a milestone in the field of DNA sensing.The engagement of cGAS by double-stranded DNA from different origins,including invading pathogens,damaged mitochondria,ruptured micronuclei,and genomic DNA results in the generation of cGAMP and activation of stimulator of interferon genes,which thereby activates innate immunity mainly characterized by the activation of type I interferon response.In recent years,great progress has been made in understanding the subcellular localization and novel functions of cGAS.In this review,we particularlyfocus on summarizingthe multifaceted roles ofcGAS in regulating senescence,autophagy,cell stemness,apoptosis,angiogenesis,cell proliferation,antitumor effect,DNA replication,DNA damage repair,micronucleophagy,as well as cell metabolism.

Aerosolized immunotherapeutic nanoparticle inhalation potentiates PD-L1 blockade for locally advanced lung cancer

Despite therapeutic advancements,the prognosis of locally advanced non-small cell lung cancer(LANSCLC),which has invaded multiple lobes or the other lung and intrapulmonary lymph nodes,remains poor.The emergence of immunotherapy with immune checkpoint blockade(ICB)is transforming cancer treatment.However,only a fraction of lung cancer patients benefit from ICB.Significant clinical evidence suggests that the proinflammatory tumor microenvironment(TME)and programmed death-ligand 1(PD-L1)expression correlate positively with response to the PD-1/PD-L1 blockade.We report here a liposomal nanoparticle loaded with cyclic dinucleotide and aerosolized(AeroNP-CDN)for inhalation delivery to deep-seated lung tumors and target CDN to activate stimulators of interferon(IFN)genes in macrophages and dendritic cells(DCs).Using a mouse model that recapitulates the clinical LANSCLC,we show that AeroNP-CDN efficiently mitigates the immunosuppressive TME by reprogramming tumor-associated macrophage from the M2 to M1 phenotype,activating DCs for effective tumor antigen presentation and increasing tumor-infiltrating CD8+T cells for adaptive anticancer immunity.Intriguingly,activation of interferons by AeroNP-CDN also led to increased PD-L1 expression in lung tumors,which,however,set a stage for response to anti-PD-L1 treatment.Indeed,anti-PD-L1 antibody-mediated blockade of IFNs-induced immune inhibitory PD-1/PD-L1 signaling further prolonged the survival of the LANSCLC-bearing mice.Importantly,AeroNP-CDN alone or combination immunotherapy was safe without local or systemic immunotoxicity.In conclusion,this study demonstrates a potential nano-immunotherapy strategy for LANSCLC,and mechanistic insights into the evolution of adaptive immune resistance provide a rational combination immunotherapy to overcome it.

Nano-STING agonist-decorated microrobots boost innate and adaptive anti-tumor immunity

Activating the cyclic guanosine monophosphate-adenosine monophosphate synthase/stimulator of interferon genes(cGAS/STING)signaling has emerged as a promising anti-tumor strategy due to the important role of the pathway in innate and adaptive immunity,yet the selective delivery of STING agonists to tumors following systemic administration remains challenging.Herein,we develop a nano-STING agonist-decorated microrobot platform to achieve the enhanced anti-tumor effect.Fe ions and the STING agonist 2’3’-cyclic guanosine monophosphate-adenosine monophosphate(cGAMP)are co-encapsulated in the mitochondria-targeting nanoparticles(mTNPs),which can trigger the release of mitochondrial DNA(mtDNA)by Fenton reactioninduced mitochondria oxidative damage.The exogenous cGAMP and the endogenous mtDNA can work synergistically to induce potent cGAS/STING signaling activation.Furthermore,we decorate mTNPs onto Salmonella typhimurium VNP20009(VNP)bacteria to facilitate tumor accumulation and deep penetration.We demonstrate that the systemic administration of this microrobot activates both innate and adaptive immunity,improving the immunotherapeutic efficacy of the STING agonists.

STING negatively regulates allogeneic T-cell responses by constraining antigen-presenting cell function

Stimulator of interferon genes(STING)-mediated innate immune activation plays a key role in tumor-and self-DNA-elicited antitumor immunity and autoimmunity.However,STING can also suppress tumor immunity and autoimmunity.STING signaling In host nonhematopoietic cells was reported to either protect against or promote graft-versus-host disease(GVHD),a major complication of allogeneic hematopoietic cell transplantation(allo-HCT).Host hematopoietic antigen-presenting cells(APCs)play key roles in donor T-cell priming during GVHD initiation.However,how STING regulates host hematopoietic APCs after allo-HCT remains unknown.We utilized murine models of allo-HCT to assess the role of STING in hematopoietic APCs.STING-deficient recipients developed more severe GVHD after major histocompatibility complex-mismatched allo-HCT.Using bone marrow chimeras,we found that STING deficiency in host hematopoietic cells was primarily responsible for exacerbating the disease.Furthermore,STING on host CD11c+cells played a dominant role in suppressing allogeneic T-cell responses.Mechanistically,STING deficiency resulted in increased survival,activation,and function of APCs,including macrophages and dendritic cells.Consistently,constitutive activation of STING attenuated the survival,activation,and function of APCs isolated from STING V154M knock-in mice.STING-deficient APCs augmented donor T-cell expansion,chemokine receptor expression,and migration into intestinal tissues,resulting in accelerated/exacerbated GVHD.Using pharmacologic approaches,we demonstrated that systemic administration of a STING agonist(bis-(3'-5')-cyclic dimeric guanosine monophosphate)to recipient mice before transplantation significantly reduced GVHD mortality.In conclusion,we revealed a novel role of STING in APC activity that dictates T-cell allogeneic responses and validated STING as a potential therapeutic target for controlling GVHD after allo-HCT.

STING and TLR7/8 agonists-based nanovaccines for synergistic antitumor immune activation

Immunostimulatory therapies based on pattern recognition receptors(PRRs)have emerged as an effective approach in the fight against cancer,with the ability to recruit tumor-specific lymphocytes in a low-immunogenicity tumor environment.The agonist cyclic dinucleotides(CDNs)of the stimulator of interferon gene(STING)are a group of very promising anticancer molecules that increase tumor immunogenicity by activating innate immunity.However,the tumor immune efficacy of CDNs is limited by several factors,including relatively narrow cytokine production,inefficient delivery to STING,and rapid clearance.In addition,a single adjuvant molecule is unable to elicit a broad cytokine response and thus cannot further amplify the anticancer effect.To address this problem,two or more agonist molecules are often used together to synergistically enhance immune efficacy.In this work,we found that a combination of the STING agonist CDGSF and the Toll-like receptor 7/8(TLR7/8)agonist 522 produced a broader cytokine response.Subsequently,we developed multicomponent nanovaccines(MCNVs)consisting of a PC7A polymer as a nanocarrier encapsulating the antigen OVA and adjuvant molecules.These MCNVs activate bone marrow-derived dendritic cells(BMDCs)to produce multiple proinflammatory factors that promote antigen cross-presentation to stimulate specific antitumor Tcell responses.In in vivo experiments,we observed that MCNVs triggered a strong T-cell response in tumor-infiltrating lymphocytes,resulting in significant tumor regression and,notably,a 100%survival rate in mice through 25 days without other partnering therapies.These data suggest that our nanovaccines have great potential to advance cancer immunotherapy with increased durability and potency.