Stimulator Of Interferon Gene Research Articles

Macrophage-Derived GSDMD Plays an Essential Role in Atherosclerosis and Cross Talk Between Macrophages via the Mitochondria-STING-IRF3/NF-κB Axis.

Macrophages play a crucial role in atherosclerotic plaque formation, and the death of macrophages is a vital factor in determining the fate of atherosclerosis. GSDMD (gasdermin D)-mediated pyroptosis is a programmed cell death, characterized by membrane pore formation and inflammatory factor release. ApoE-/- and Gsdmd-/- ApoE-/- mice, bone marrow transplantation, and AAV-F4/80-shGSDMD were used to examine the effect of macrophage-derived GSDMD on atherosclerosis. Single-cell RNA sequencing was used to investigate the changing profile of different cellular components and the cellular localization of GSDMD during atherosclerosis. First, we found that GSDMD is activated in human and mouse atherosclerotic plaques and Gsdmd-/- attenuates the atherosclerotic lesion area in high-fat diet-fed ApoE-/- mice. We performed single-cell RNA sequencing of ApoE-/- and Gsdmd-/- ApoE-/- mouse aortas and showed that GSDMD is principally expressed in atherosclerotic macrophages. Using bone marrow transplantation and AAV-F4/80-shGSDMD, we identified the potential role of macrophage-derived GSDMD in aortic pyroptosis and atherosclerotic injuries in vivo. Mechanistically, GSDMD contributes to mitochondrial perforation and mitochondrial DNA leakage and subsequently activates the STING (stimulator of interferon gene)-IRF3 (interferon regulatory factor 3)/NF-κB (nuclear factor kappa B) axis. Meanwhile, GSDMD regulates the STING pathway activation and macrophage migration via cytokine secretion. Inhibition of GSDMD with GSDMD-specific inhibitor GI-Y1 can effectively alleviate the progression of atherosclerosis. Our study has provided a novel macrophage-derived GSDMD mechanism in the promotion of atherosclerosis and demonstrated that GSDMD can be a potential therapeutic target for atherosclerosis.

A senescence-mimicking (senomimetic) VEGFR TKI side-effect primes tumor immune responses via IFN/STING signaling.

Tyrosine kinase inhibitors (TKIs) that block the vascular endothelial growth factor receptors (VEGFRs) disrupt tumor angiogenesis but also have many unexpected side-effects that impact tumor cells directly. This includes the induction of molecular markers associated with senescence, a form of cellular aging that typically involves growth arrest. We have shown that VEGFR TKIs can hijack these aging programs by transiently inducting senescence-markers (SMs) in tumor cells to activate senescence-associated secretory programs that fuel drug resistance. Here we show that these same senescence-mimicking ('senomimetic') VEGFR TKI effects drive an enhanced immunogenic signaling that, in turn, can alter tumor response to immunotherapy. Using a live-cell sorting method to detect beta-galactosidase, a commonly used SM, we found that subpopulations of SM-expressing (SM+) tumor cells have heightened interferon (IFN) signaling and increased expression of IFN-stimulated genes (ISGs). These ISG increases were under the control of the STimulator of INterferon Gene (STING) signaling pathway, which we found could be directly activated by several VEGFR TKIs. TKI-induced SM+ cells could stimulate or suppress CD8 T-cell activation depending on host:tumor cell contact while tumors grown from SM+ cells were more sensitive to PD-L1 inhibition in vivo, suggesting that offsetting immune-suppressive functions of SM+ cells can improve TKI efficacy overall. Our findings may explain why some (but not all) VEGFR TKIs improve outcomes when combined with immunotherapy and suggest that exploiting senomimetic drug side-effects may help identify TKIs that uniquely 'prime' tumors for enhanced sensitivity to PD-L1 targeted agents.

Design, synthesis, and evaluation of thiazolecarboxamide derivatives as stimulator of interferon gene inhibitors.

Stimulator of interferon gene (STING) plays critical roles in the cytoplasmic DNA-sensing pathway and in the induction of inflammatory response. Aberrant cytoplasmic DNA accumulation and STING activation are implicated in numerous inflammatory and autoimmune diseases. Here, we reported the discovery of a series of thiazolecarboxamide-based STING inhibitors through a molecular planarity/symmetry disruption strategy. The privileged compound 15b significantly inhibited STING signaling and suppressed immune-inflammatory cytokine levels in both human and murine cells. In vivo experiments demonstrated 15b effectively ameliorated immune-inflammatory cytokines upregulation in MSA-2-stimulated and Trex1-D18N mice. Furthermore, compound 15b exhibited enhanced efficacy in suppressing interferon-stimulated gene 15 (ISG15), a critical positive feedback regulator of STING. Overall, compound 15b deserves further development for the treatment of STING-associated inflammatory and autoimmune diseases.

Tumor Exosomal ENPP1 Hydrolyzes cGAMP to Inhibit cGAS-STING Signaling.

To evade immune surveillance, tumor cells express ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) on the surface of their membrane, which degrades extracellular cyclic GMP-AMP (cGAMP), thereby inhibiting the cyclic GMP-AMP synthase (cGAS) stimulator of interferon gene (STING) DNA-sensing pathway. To fully understand this tumor stealth mechanism, it is essential to determine whether other forms of ENPP1 with hydrolytic cGAMP activity also are present in the tumor microenvironment to regulate this innate immune pathway. Herein, it is reported that various tumor-derived exosomes carry ENPP1, and can hydrolyze synthetic 2'3'-cGAMP and endogenous 2'3'-cGAMP produced by cells to inhibit cGAS-STING pathway in immune cells. Moreover, tumor exosomal ENPP1 also can hydrolyze 2'3'-cGAMP bound to LL-37 (an effective transporter of 2'3'-cGAMP) to inhibit STING signaling. Furthermore, high expression of ENPP1 in exosomes is observed isolated from human breast and lung cancer tissue, and tumor exosomal ENPP1 inhibited the immune infiltration of CD8+ T cells and CD4+ T cells. The results elucidate the essential function of tumor exosomal ENPP1 in the cGAS-STING pathway, furthering understanding of the crosstalk between the tumor cells and immune system.

5,6-dimethylxanthenone-4-acetic acid (DMXAA), a partial STING agonist, competes for human STING activation.

5,6-dimethylxanthenone-4-acetic acid (DMXAA) is a mouse-selective stimulator of interferon gene (STING) agonist exerting STING-dependent anti-tumor activity. Although DMXAA cannot fully activate human STING, DMXAA reached phase III in lung cancer clinical trials. How DMXAA is effective against human lung cancer is completely unknown. Here, we show that DMXAA is a partial STING agonist interfering with agonistic STING activation, which may explain its partial anti-tumor effect observed in humans, as STING was reported to be pro-tumorigenic for lung cancer cells with low antigenicity. Furthermore, we developed a DMXAA derivative-3-hydroxy-5-(4-hydroxybenzyl)-4-methyl-9H-xanthen-9-one (HHMX)-that can potently antagonize STING-mediated immune responses both in humans and mice. Notably, HHMX suppressed aberrant responses induced by STING gain-of-function mutations causing STING-associated vasculopathy with onset in infancy (SAVI) in in vitro experiments. Furthermore, HHMX treatment suppressed aberrant STING pathway activity in peripheral blood mononuclear cells from SAVI patients. Lastly, HHMX showed a potent therapeutic effect in SAVI mouse model by mitigating disease progression. Thus, HHMX offers therapeutic potential for STING-associated autoinflammatory diseases.

The antiviral role of largemouth bass STING against iridovirus infection

Stimulator of interferon gene (STING) plays a crucial role in the innate immune response against viral and bacterial pathogens. However, its function in largemouth bass iridovirus (LMBV) infection remains uncertain. Here, a STING homolog (MsSTING) from largemouth bass (Micropterus salmoides) was cloned and characterized. MsSTING encoded a 407-amino-acid polypeptide, which shared 84.08% and 41.45% identity with golden perch (Perca flavescens) and human (Homo sapiens) homologs, respectively. MsSTING contained four transmembrane domains and a conserved C-terminal domain. The mRNA level of MsSTING was significantly increased in response to LMBV infection in vitro. Subcellular localization observation indicated that MsSTING encoded a cytoplasmic protein, which co-localized predominantly with endoplasmic reticulum (ER) and partially with mitochondria. Moreover, its accurate localization was dependent on the N-terminal transmembrane motif (TM) domains. MsSTING was able to activate interferon (IFN) response, evidenced by the activation of IFN1, IFN3 and ISRE promoters by its overexpression in vitro. Mutant analysis showed that both the N-terminal and C-terminal domain of MsSTING were essential for its activation on IFN response. In addition, overexpression of MsSTING inhibited the transcription and protein levels of viral core genes, indicating that MsSTING exerted antiviral action against LMBV. Consistently, the inhibitory effects were significantly attenuated when the N-terminal or C-terminal domains of MsSTING was deleted. Furthermore, MsSTING overexpression upregulated the transcriptions of interferon-related genes and pro-inflammatory factors, including TANK-binding kinase 1(TBK1), interferon regulatory factor 3 (IRF3), interferon regulatory factor 7 (IRF7), interferon stimulated exonuclease gene 20 (ISG20), interferon-induced transmembrane protein 1(IFITM1), interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6). Together, MsSTING exerted antiviral action upon LMBV infection through positive regulation the innate immune response.

Role of mitochondrial dysfunction in kidney disease: Insights from the cGAS-STING signaling pathway.

Over the past decade, mitochondrial dysfunction has been investigated as a key contributor to acute and chronic kidney disease. However, the precise molecular mechanisms linking mitochondrial damage to kidney disease remain elusive. The recent insights into the cyclic guanosine monophosphate-adenosine monophosphate (GMP-AMP) synthetase (cGAS)-stimulator of interferon gene (STING) signaling pathway have revealed its involvement in many renal diseases. One of these findings is that mitochondrial DNA (mtDNA) induces inflammatory responses via the cGAS-STING pathway. Herein, we provide an overview of the mechanisms underlying mtDNA release following mitochondrial damage, focusing specifically on the association between mtDNA release-activated cGAS-STING signaling and the development of kidney diseases. Furthermore, we summarize the latest findings of cGAS-STING signaling pathway in cell, with a particular emphasis on its downstream signaling related to kidney diseases. This review intends to enhance our understanding of the intricate relationship among the cGAS-STING pathway, kidney diseases, and mitochondrial dysfunction.

Inhibition of spinal BRD4 alleviates pyroptosis and M1 microglia polarization via STING-IRF3 pathway in morphine-tolerant rats

BackgroundMorphine tolerance has been a challenging medical issue. Neuroinflammation is considered as a critical mechanism for the development of morphine tolerance. Bromodomain-containing protein 4 (BRD4), a key regulator in cell damage and inflammation, participates in the development of chronic pain. However, whether BRD4 is involved in morphine tolerance and the underlying mechanisms remain unknown. MethodsThe morphine-tolerant rat model was established by intrathecal administration of morphine twice daily for 7 days. Behavior test was assessed by a tail-flick latency test. The roles of BRD4, pyroptosis, microglia polarization and related signaling pathways in morphine tolerance were elucidated by Western blot, real-time quantitative polymerase chain reaction, and immunofluorescence. ResultsRepeated morphine administration upregulated BRD4 level, induced pyroptosis, and promoted microglia M1-polarization in spinal cord, accompanied by the release of proinflammatory cytokines, such as TNF-α and IL-1β. JQ-1, a BRD4 antagonist, alleviated the development of morphine tolerance, diminished pyroptosis and induced the switch of microglia from M1 to M2 phenotype. Mechanistically, stimulator of interferon gene (STING)- interferon regulatory factor 3 (IRF3) pathway was activated and the protective effect of JQ-1 against morphine tolerance was at least partially mediated by inhibition of STING-IRF3 pathway. ConclusionThis study demonstrated for the first time that spinal BRD4 contributes to pyroptosis and switch of microglia polarization via STING-IRF3 signaling pathway during the development of morphine tolerance, which extend the understanding of the neuroinflammation mechanism of morphine tolerance and provide an alternative strategy for the precaution against of this medical condition.

Effect of resveratrol on herpesvirus encephalitis: Evidences for its mechanisms of action

BackgroundHerpes simplex virus type 1 (HSV-1)-induced herpes simplex encephalitis (HSE) has a high mortality rate in clinically immunocompromised patients, while recovered patients often experience neurological sequelae due to neuroinflammation. Nucleoside drugs and nucleoside analogues such as acyclovir and ganciclovir are mainly used in clinical treatment, and the emergence of resistant viral strains makes the development of new anti-herpesvirus encephalitis drugs urgent. Resveratrol is a multifunctional, plant-derived bioactive compound and its antiviral potential is attracting much attention. PurposeThis study aimed to investigate the anti-HSV-1 mechanism of resveratrol in microglial cells and in the HSE mouse model. MethodsThe antiviral effect of resveratrol on HSV-1 infection was investigated by plaque assay, virus titer, immunofluorescence, Western blot and time-of-addition assay. The influence of resveratrol on stimulator of interferon gene (STING)/Nuclear Factor kappa B (NF-κB) signaling pathway-mediated neuroinflammation was examined by Western blot, RT-qPCR and ELISA. The interaction between resveratrol and STING/heat shock protein 90 beta (HSP90β) was evaluated by molecular modeling, co-immunoprecipitation, and drug affinity responsive target stability assay. The therapeutic effect of resveratrol on HSE was evaluated in the HSE mouse model by analyzing weight loss, neurodegenerative symptoms and histopathological scores. ResultsResveratrol inhibited the early process of HSV-1 infection, and interfered with the STING/NF-κB signaling pathway to attenuate HSV-1-induced neuroinflammation and microglial M1 polarization, independent of its classical target Sirtuin1. Mechanistically, resveratrol completely bound to Glu515 and Lys491 of HSP90β, thus disrupting the HSP90β-STING interaction and promoting STING degradation. Resveratrol also significantly alleviated viral encephalitis and neuroinflammation caused by HSV-1 in the HSE mouse model. ConclusionResveratrol acted as a non-classical HSP90β inhibitor, binding to the STING-HSP90β interaction site to promote STING degradation and attenuate HSV-1-induced encephalitis and neuroinflammation. These findings suggest the alternative strategy of targeting HSP90β and resveratrol-mediated inhibition of HSP90β as a potential antiviral approach.

Experimental Type 2 diabetes and lipotoxicity-associated neuroinflammation involve mitochondrial DNA-mediated cGAS/STING axis: implication of Type-1 interferon response in cognitive impairment.

Type-1 IFN (interferon)-associated innate immune response is increasingly getting attention in neurodegenerative and metabolic diseases like type 2 diabetes (T2DM). However, its significance in T2DM/lipotoxicity-induced neuroglia changes and cognitive impairment is missing. The present study aims to evaluate the involvement of cGAS (cyclic GMP-AMP synthase)-STING (stimulator of interferon gene), IRF3 (interferon regulatory factor-3), TBK (TANK binding kinase)-mediated Type-1 IFN response in the diabetic brain, and lipotoxicity (palmitate-bovine serum albumin conjugate/PA-BSA)-induced changes in cells (neuro2a and BV2). T2DM was induced in C57/BL6 mice by feeding on a high-fat diet (HFD, 60% Kcal) for 16weeks and injecting a single dose of streptozotocin (100mg/kg, i.p) in the 12th week. Plasma biochemical parameter analysis, neurobehavioral assessment, protein expression, and quantitative polymerase chain reaction study were carried out to decipher the hypothesis. T2DM-associated metabolic and lipotoxic stress led to mitochondrial impairment causing leakage of mtDNA to the cytoplasm further commencing cGAS activation and its downstream signaling. The diseased hippocampus and cortex showed decreased expression of synaptophysin (p < 0.01) and PSD-95 (p < 0.01, p < 0.05) with increased expression of cGAS (p < 0.001), p-STING (p < 0.001), p-STAT1 (signal transducer and activator of transcription) (p < 0.01), and IFN-β (p < 0.001) compared to normal control. The IFN-β/p-STAT1-mediated microglia activation was executed employing a conditioned media approach. C-176, a selective STING inhibitor, alleviated cGAS/p-STING/IFN-β expression and proinflammatory microglia/M1-associated markers (CD16 expression, CXCL10, TNF-α, IL-1β mRNA fold change) in the diabetic brain. The present study suggests Type-1IFN response may result in neuroglia dyshomeostasis affecting normal brain function. Alleviating STING signaling has the potential to protect T2DM-associated central ailment.

Nanoadjuvant-triggered STING activation evokes systemic immunotherapy for repetitive implant-related infections

Repetitive implant-related infections (IRIs) are devastating complications in orthopedic surgery, threatening implant survival and even the life of the host. Biofilms conceal bacterial-associated antigens (BAAs) and result in a "cold tumor"-like immune silent microenvironment, allowing the persistence of IRIs. To address this challenge, an iron-based covalent organic framed nanoadjuvant doped with curcumin and platinum (CFCP) was designed in the present study to achieve efficient treatment of IRIs by inducing a systemic immune response. Specifically, enhanced sonodynamic therapy (SDT) from CFCP combined with iron ion metabolic interference increased the release of bacterial-associated double-stranded DNA (dsDNA). Immunogenic dsDNA promoted dendritic cell (DC) maturation through activation of the stimulator of interferon gene (STING) and amplified the immune stimulation of neutrophils via interferon-β (IFN-β). At the same time, enhanced BAA presentation aroused humoral immunity in B and T cells, creating long-term resistance to repetitive infections. Encouragingly, CFCP served as neoadjuvant immunotherapy for sustained antibacterial protection on implants and was expected to guide clinical IRI treatment and relapse prevention.

Circulating immunotherapy strategy based on pyroptosis and STING pathway: Mn-loaded paclitaxel prodrug nanoplatform against tumor progression and metastasis

Immunotherapy has emerged as a promising strategy against tumors. However, its efficacy is limited by low immunogenicity, poor antigen presentation, and inadequate lymphocyte infiltration. Herein, we develop a nanoplatform (Mn-HSP) loaded with manganese ions (Mn2+) and paclitaxel (PTX) prodrug based on hyaluronic acid. PTX in Mn-HSP induces DNA damage and pyroptosis to release tumor-associated antigens (TAAs), enhancing tumor-specific adaptive immunity. Meanwhile, Mn2+ in Mn-HSP, together with PTX-induced DNA damage, activates the stimulator of interferon gene (STING) pathway to amplify innate immunity. Mn-HSP combines with adaptive and innate immunity, effectively enhancing the presentation of antigen-presenting cells (APCs) and promoting tumor infiltration of cytotoxic T lymphocytes (CTLs). In turn, the granzyme B (GZMB) secreted by CTLs triggers pyroptosis again, thereby establishing a “circulating immunotherapy” against tumors. Our results demonstrate that Mn-HSP efficiently inhibits primary breast tumors, as well as rechallenge tumors and lung metastasis in vivo. Therefore, the circulating immunotherapy that combines pyroptosis mediated adaptive immunity and STING pathway amplified innate immunity provides a novel strategy for enhancing tumor immunotherapy.

The dual function of cGAS-STING signaling axis in liver diseases.

Numerous liver diseases, such as nonalcoholic fatty liver disease, hepatitis, hepatocellular carcinoma, and hepatic ischemia-reperfusion injury, have been increasingly prevalent, posing significant threats to global health. In recent decades, there has been increasing evidence linking the dysregulation of cyclic-GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING)-related immune signaling to liver disorders. Both hyperactivation and deletion of STING can disrupt the immune microenvironment dysfunction, exacerbating liver disorders. Consequently, there has been a surge in research investigating medical agents or mediators targeting cGAS-STING signaling. Interestingly, therapeutic manipulation of the cGAS-STING pathway has yielded inconsistent and even contradictory effects on different liver diseases due to the distinct physiological characteristics of intrahepatic cells that express and respond to STING. In this review, we comprehensively summarize recent advancements in understanding the dual roles of the STING pathway, highlighting that the benefits of targeting STING signaling depend on the specific types of target cells and stages of liver injury. Additionally, we offer a novel perspective on the suitability of STING agonists and antagonists for clinical assessment. In conclusion, STING signaling remains a highly promising therapeutic target, and the development of STING pathway modulators holds great potential for the treatment of liver diseases.

Structural insights into the regulation, ligand recognition, and oligomerization of bacterial STING

The cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) signaling pathway plays a critical protective role against viral infections. Metazoan STING undergoes multilayers of regulation to ensure specific signal transduction. However, the mechanisms underlying the regulation of bacterial STING remain unclear. In this study, we determined the crystal structure of anti-parallel dimeric form of bacterial STING, which keeps itself in an inactive state by preventing cyclic dinucleotides access. Conformational transition between inactive and active states of bacterial STINGs provides an on-off switch for downstream signaling. Some bacterial STINGs living in extreme environment contain an insertion sequence, which we show codes for an additional long lid that covers the ligand-binding pocket. This lid helps regulate anti-phage activities. Furthermore, bacterial STING can bind cyclic di-AMP in a triangle-shaped conformation via a more compact ligand-binding pocket, forming spiral-shaped protofibrils and higher-order fibril filaments. Based on the differences between cyclic-dinucleotide recognition, oligomerization, and downstream activation of different bacterial STINGs, we proposed a model to explain structure-function evolution of bacterial STINGs.

Hydrogel-immobilized nanotherapeutics: Inhibition of protective autophagy to amplify STING signals for postsurgical tumor immunotherapy

Activating the inherent stimulator of interferon gene (STING) pathway of cancer cells can inhibit tumor growth but can also induce protective autophagy of tumor cells to inhibit the STING-mediated immunotherapy. Therefore, amplification of STING activation and inhibition of autophagy could potentiate the cancer immunotherapy. Here, hydrogel-immobilized nanoparticles loaded with glucose oxidase (GOx), manganese ions (Mn2+) and hydroxychloroquine (HCQ) are prepared at the postsurgical site to enhance cancer therapy via activating the STING pathway and regulating the autophagy pathway. The delivered GOx and Mn2+ exert a chemo-dynamic therapy (CDT) to induce dsDNA damage, which can further initiate the STING pathway. HCQ can effectively inhibit protective autophagy associated with STING pathway activation, further amplify the antitumor immune responses. The synergistic delivery of CDT agents (i.e., GOx and Mn2+), STING agonists (i.e., Mn2+) and autophagy inhibitors (i.e., HCQ) results in a specific immune response, significantly inhibit tumor recurrence and metastatic tumor growth, which could extend the survival rate of mice suffered from the triple-negative breast cancer (TNBC).

Structure-based virtual screening and in vitro validation of inhibitors of cyclic dinucleotide phosphodiesterases ENPP1 and CdnP.

In this paper, we describe novel inhibitors of cyclic dinucleotide phosphodiesterase enzymes from Mycobacterium tuberculosis (M.tb) (CdnP) and mammals (ENPP1). The phosphodiesterase enzymes hydrolyze cyclic dinucleotides, such as 2',3'-cyclic GMP-AMP and c-di-AMP, which are stimulator of interferon gene (STING) agonists. By blocking the hydrolysis of STING agonists, the cyclic GMP-AMP synthase (cGAS)-STING-IRF3 pathway is potentiated. There is strong evidence in tuberculosis and in cancer biology that potentiation of the cGAS-STING-IRF3 pathway leads to improved M.tb clearance and also improved antitumor responses in cancer. In addition to the identification of novel inhibitors and their biochemical characterization, we provide proof-of-concept evidence that our E-3 inhibitor potentiates the cGAS-STING-IRF3 pathway in both macrophage cell lines and also in primary human monocyte-derived macrophages.

Single-cell RNA-sequencing of PBMCs from SAVI patients reveals disease-associated monocytes with elevated integrated stress response

Gain-of-function mutations in stimulator of interferon gene 1 (STING1) result in STING-associated vasculopathy with onset in infancy (SAVI), a severe autoinflammatory disease. Although elevated type I interferon (IFN) production is thought to be the leading cause of the symptoms observed in patients, STING can induce a set of pathways, which have roles in the onset and severity of SAVI and remain to be elucidated. To this end, we performed a multi-omics comparative analysis of peripheral blood mononuclear cells (PBMCs) and plasma from SAVI patients and healthy controls, combined with a dataset of healthy PBMCs treated with IFN-β. Our data reveal a subset of disease-associated monocyte, expressing elevated CCL3, CCL4, and IL-6, as well as a strong integrated stress response, which we suggest is the result of direct PERK activation by STING. Cell-to-cell communication inference indicates that these monocytes lead to Tcell early activation, resulting in their senescence and apoptosis. Last, we propose a transcriptomic signature of STING activation, independent of type I IFN response.

LncRNA JPX-Enriched Chromatin Microenvironment Mediates Vascular Smooth Muscle Cell Senescence and Promotes Atherosclerosis.

Senescence is a series of degenerative changes in the structure and physiological function of an organism. Whether JPX (just proximal to XIST)-a newly identified age-related noncoding RNA by us-is associated with atherosclerosis is still unknown. Our study was to investigate the role of JPX and provide insights into potential therapies targeting atherosclerosis. We analyzed clinical data from multiple tissues including meniscus tissue, leukemia cells, and peripheral blood monocytes to identify age-related noncoding RNAs in senescent vascular smooth muscle cells (VSMCs). The molecular mechanism of JPX was investigated by capture hybridization analysis of RNA targets and chromatin immunoprecipitation. IGVTools and real-time quantitative polymerase chain reaction were used to evaluate the JPX expression during phenotype regulation in age-related disease models. The therapeutic potential of JPX was evaluated after establishing an atherosclerosis model in smooth muscle-specific Jpx knockout mice. JPX expression was upregulated in activated ras allele (H-rasV12)-induced senescent VSMCs and atherosclerotic arteries. JPX knockdown substantially reduced the elevation of senescence-associated secretory phenotype (SASP) genes in senescent VSMCs. Cytoplasmic DNA leaked from mitochondria via mitochondrial permeability transition pore formed by VDAC1 (voltage-dependent anion channel 1) oligomer activates the STING (stimulator of interferon gene) pathway. JPX could act as an enhancer for the SASP genes and functions as a scaffold molecule through interacting with phosphorylated p65/RelA and BRD4 (bromodomain-containing protein 4) in chromatin remodeling complex, promoting the transcription of SASP genes via epigenetic regulation. Smooth muscle knockout of Jpx in ApoeKO mice resulted in a decrease in plaque area, a reduction in SASP gene expression, and a decrease in senescence compared with controls. As an enhancer RNA, JPX can integrate p65 and BRD4 to form a chromatin remodeling complex, activating SASP gene transcription and promoting cellular senescence. These findings suggest that JPX is a potential therapeutic target for the treatment of age-related atherosclerosis.

Optogenetic STING clustering system through nanobody-fused photoreceptor for innate immune regulation

Stimulator of interferon gene (STING) serves as a key mediator for regulating innate immune response. Despite the dynamic process of STING activation, the role of STING clustering in the STING-mediated immune response remains unclear due to the lack of a suitable tool. We developed an innovative optogenetic STING clustering system, OptoSTING, that employs a nanobody-fused photoreceptor-driven technique to achieve light-responsive STING clustering. By optimizing the protein configuration, we identified an optimal OptoSTING system that induced efficient, robust, and reversible clustering of STING upon blue-light illumination. We confirmed that light-induced STING clustering required ER exit to trigger the stimulation of type I interferon response because only cytosolic fragment of OptoSTING (cyt-OptoSTING) enabled to initiate immune response, not full-length OptoSTING. The precise and temporally controlled clustering by cyt-OptoSTING revealed that STING clustering facilitated the STING signaling pathway through puncta formation of IRF3 as downstream effector protein.

The STING-IRF3 Signaling Pathway, Mediated by Endoplasmic Reticulum Stress, Contributes to Impaired Myocardial Autophagic Flux After Ischemia/Reperfusion.

This study aimed to determine whether endoplasmic reticulum (ER) stress is involved in impaired autophagy after myocardial ischemia/reperfusion (M-I/R) and elucidate the underlying mechanisms. The expression levels of stimulator of interferon gene (STING) and interferon regulatory transcription factor 3 (IRF3) phosphorylation increased in M-I/R heart tissues and hypoxia-treated/reoxygenation-treated H9c2 cells. The ER stress inhibitor 4-phenylbutyric acid (4-PBA) significantly suppressed the stimulation of STING-IRF3 transcription and alleviated cardiac dysfunction caused by M-I/R injury. In addition, 4-PBA reversed ischemia-induced/reperfusion-induced autophagic flux dysfunction, as demonstrated by a decrease in p 62 and LC3 levels. Similarly, the protective effect of STING deficiency on myocardial cell damage was achieved by the recovery of autophagic flux. Conversely, the protective effect of 4-PBA against hypoxia/reoxygenation injury in cardiomyocytes was offset by STING overexpression, wherein the activated STING-IRF3 pathway promoted the expression of Rubicon (a negatively-regulated autophagic molecule) by binding to the Rubicon promoter. Rubicon ablation effectively counteracts the adverse effects of STING overexpression in cardiomyocytes. The data showed that STING-IRF3 signaling of ER stress receptors is particularly important in the progression of physiological M-I/R caused by the inhibition of autophagic flow in vivo and in vitro.