A hnRNPA2B1 agonist effectively inhibits HBV and SARS-CoV-2 omicron in vivo

The twenty-first century has already recorded more than ten major epidemics or pandemics of viral disease, including the devastating COVID-19. Novel effective antivirals with broad-spectrum coverage are urgently needed. Herein, we reported a novel broad-spectrum antiviral compound PAC5. Oral administration of PAC5 eliminated HBV cccDNA and reduced the large antigen load in distinct mouse models of HBV infection. Strikingly, oral administration of PAC5 in a hamster model of SARS-CoV-2 omicron (BA.1) infection significantly decreases viral loads and attenuates lung inflammation. Mechanistically, PAC5 binds to a pocket near Asp49 in the RNA recognition motif of hnRNPA2B1. PAC5-bound hnRNPA2B1 is extensively activated and translocated to the cytoplasm where it initiates the TBK1-IRF3 pathway, leading to the production of type I IFNs with antiviral activity. Our results indicate that PAC5 is a novel small-molecule agonist of hnRNPA2B1, which may have a role in dealing with emerging infectious diseases now and in the future.

Expression and role of STING-TBK1-IRF3 signaling pathway in the brain of mice with chronic stress / 西安交通大学学报(医学版)

【Objective】 To explore the expression and role of stimulator of interferon gene (STING)-TANK-binding kinase 1 (TBK1)-interferon regulatory factor 3 (IRF3) signaling pathway in the brain of chronic stress mice. 【Methods】 Mice were divided into control (CON) group and chronic restraint stress (RST) group. Mice in the RST group were given chronic restraint stress stimulation (6 hours per day, 14 days). After 14 days, the mRNA expressions of pro-inflammatory cytokines CCL2, CXCL10, IL-1β, IL-6, IL-10, and TNFα in the brain were detected and analyzed by qRT-PCR; protein expression of STING, TBK1, p-TBK1, IRF3, and p-IRF3 were detected and analyzed by immunofluorescence staining and Western blotting. 【Results】 Compared to the CON group, the mRNA expressions of pro-inflammatory cytokines in the RST group were significantly increased (P<0.05). STING and microglia marker Iba-1 were highly co-located and the expression of STING was decreased as detected by immunofluorescence staining. Moreover, the protein expressions of STING, p-TBK1, and p-IRF3 were significantly decreased (all P<0.01). 【Conclusion】 Chronic restraint stress triggers a neuroinflammatory response and the STING-TBK1-IRF3 pathway in the brain of the RST mice is significantly inhibited.

Palmitic acid suppresses autophagy in neonatal rat cardiomyocytes via the cGAS-STING-IRF3 pathway / 南方医科大学学报

OBJECTIVE@#To investigate the effect of palmitic acid (PA) on autophagy in neonatal rat cardiomyocytes (NRCMs) and explore the underlying mechanism.@*METHODS@#NRCMs were isolated and cultured for 24 h before exposure to 10% BSA and 0.1, 0.3, 0.5, or 0.7 mmol/L PA for 24 h. After the treatments, the expressions of Parkin, PINK1, p62, LC3Ⅱ/ LC3Ⅰ, cGAS, STING and p-IRF3/IRF3 were detected using Western blotting and the cell viability was assessed with CCK8 assay, based on which 0.7 mmol/L was selected as the optimal concentration in subsequent experiments. The effects of cGAS knockdown mediated by cGAS siRNA in the presence of PA on autophagy-related proteins in the NRCMs were determined using Western blotting, and the expressions of P62 and LC3 in the treated cells were examined using immunofluorescence assay.@*RESULTS@#PA at different concentrations significantly lowered the expressions of Parkin, PINK1, LC3 Ⅱ/LC3 Ⅰ and LC3 Ⅱ/LC3 Ⅰ+Ⅱ (P < 0.05), increased the expression of p62 (P < 0.05), and inhibited the viability of NRCMs (P < 0.05). Knockdown of cGAS obviously blocked the autophagy-suppressing effect of PA and improved the viability of NRCMs (P < 0.05).@*CONCLUSION@#PA inhibits autophagy by activating the cGAS-STING-IRF3 pathway to reduce the viability of NRCMs.

Histone deacetylase 3 promotes innate antiviral immunity through deacetylation of TBK1

TANK-binding kinase 1 (TBK1), a core kinase of antiviral pathways, activates the production of interferons (IFNs). It has been reported that deacetylation activates TBK1; however, the precise mechanism still remains to be uncovered. We show here that during the early stage of viral infection, the acetylation of TBK1 was increased, and the acetylation of TBK1 at Lys241 enhanced the recruitment of IRF3 to TBK1. HDAC3 directly deacetylated TBK1 at Lys241 and Lys692, which resulted in the activation of TBK1. Deacetylation at Lys241 and Lys692 was critical for the kinase activity and dimerization of TBK1 respectively. Using knockout cell lines and transgenic mice, we confirmed that a HDAC3 null mutant exhibited enhanced susceptibility to viral challenge via impaired production of type I IFNs. Furthermore, activated TBK1 phosphorylated HDAC3, which promoted the deacetylation activity of HDAC3 and formed a feedback loop. In this study, we illustrated the roles the acetylated and deacetylated forms of TBK1 play in antiviral innate responses and clarified the post-translational modulations involved in the interaction between TBK1 and HDAC3.

Role of lentinan combined with AdIRF3 inhibiting breast cancer growth through enhancing IFN-β secretion / 中草药

Objective To investigate the effect of lentinan (LNT) combined with IRF3 expressing adenovirus vector on the anti-tumor therapy, and its underlying mechanism. Methods Balb/c bearing TUBO mice were treated with PBS, AdGFP, AdIRF3, LNT, and LNT combined with AdIRF3 to observe the tumor growth curve of mice. qPCR was used to detect the IFN-β level of tumor tissues. ELISPOT was to check the IFN-γ secretion of spleen cells. FACS was used to make sure the percentage of tumor infiltrated T cells. Balb/c-nu mice were inoculated with TUBO cells, and tumor growth was monitored. Anti-IFNAR1 antibody was injected to Babl/c bearing mice, and tumor growth was measured. Results Compared with control groups, LNT combined with AdIRF3 can inhibit the tumor growth and increase the IFN-γ secretion of TUBO-bearing mice. There was no significant difference of the percentage of tumor infiltrated Treg among groups, but the tumor infiltrated CD8+T was significantly higher in LNT combined with AdIRF3 treated mice group. There was no significant difference of tumor growth between Balb-nu mice inoculated with TUBO cells treated by LNT/AdIRF3 and PBS/AdGFP group. The tumor growth was not inhibited in Babl/c bearing mice injected with anti-IFNAR1 antibody and treated by LNT/AdIRF3. Conclusion LNT combined with AdIRF3 can inhibit the tumor growth by activating the IRF3-IFN signaling pathway.

Hydroquinone suppresses IFN-β expression by targeting AKT/IRF3 pathway

Previous studies have demonstrated the role of hydroquinone (HQ), a hydroxylated benzene metabolite, in modulating various immune responses; however, its role in macrophage-mediated inflammatory responses is not fully understood. In this study, the role of HQ in inflammatory responses and the underlying molecular mechanism were explored in macrophages. HQ down-regulated the expression of interferon (IFN)-β mRNA in LPS-stimulated RAW264.7 cells without any cytotoxicity and suppressed interferon regulatory factor (IRF)-3-mediated luciferase activity induced by TIR-domain-containing adapter-inducing interferon-β (TRIF) and TANK-binding kinase 1 (TBK1). A mechanism study revealed that HQ inhibited IRF-3 phosphorylation induced by lipopolysaccharide (LPS), TRIF, and AKT by suppressing phosphorylation of AKT, an upstream kinase of the IRF-3 signaling pathway. IRF-3 phosphorylation is highly induced by wild-type AKT and poorly induced by an AKT mutant, AKT C310A, which is mutated at an inhibitory target site of HQ. We also showed that HQ inhibited IRF-3 phosphorylation by targeting all three AKT isoforms (AKT1, AKT2, and AKT3) in RAW264.7 cells and suppressed IRF-3-mediated luciferase activities induced by AKT in HEK293 cells. Taken together, these results strongly suggest that HQ inhibits the production of a type I IFN, IFN-β, by targeting AKTs in the IRF-3 signaling pathway during macrophage-mediated inflammation.

Different regulation profiles of LPS-activated TLR4 on NF-κB and IRF3 signaling pathway / 基础医学与临床

Objective To investigate the different regulation of TLR4 between NF-κB and IRF3 signaling pathways which are triggered by LPS. Methods LPS was used to stimulate mouse peritoneal macrophages. Immunofluores-cence was performed to find the translocation of TLR4 and the transcription factors p65 and IRF3. The phosphoryla-tion level of transcription factors was examined by Western blot. Results With stimulation of LPS in 30 minutes, the fluorescence intensity of TLR4 on the cytomembrane was increased (P<0.01),while its fluorescence intensity on the endosome in cytoplasm was increased more robustly(P<0.01),and TLR4 in cytoplasm was found to co-lo-cate with EEA1. When the stimulation reached 90 minutes and 180 minutes,the fluorescence intensity of TLR4 in both cytomembrane and cytoplasm decreased obviously (P<0.01),and the co-location with EEA1 was attenuated present (P<0.01). In the rest state,the fluorescence intensity of the downstream molecule p65 and IRF3 was al-most totally in the cytoplasm. After the stimulation of LPS, fluorescence intensity both in nucleus was increased gradually (P<0.05),but the fluorescence intensity of p65 in nucleus was enhanced earlier and lasted longer than that of IRF3. The phosphorylation of p65 was also earlier and lasted longer than that of IRF3. Conclusions The changed location of TLR4 after being activated can make the transfer time of IRF3 pathway longer and the lasting time shorter than that of NF-κB robustly.

Different regulation profiles of LPS-activated TLR4 on NF-κB and IRF3 signaling pathway / 基础医学与临床

Objective To investigate the different regulation of TLR4 between NF-κB and IRF3 signaling pathways which are triggered by LPS. Methods LPS was used to stimulate mouse peritoneal macrophages. Immunofluores-cence was performed to find the translocation of TLR4 and the transcription factors p65 and IRF3. The phosphoryla-tion level of transcription factors was examined by Western blot. Results With stimulation of LPS in 30 minutes, the fluorescence intensity of TLR4 on the cytomembrane was increased (P<0.01),while its fluorescence intensity on the endosome in cytoplasm was increased more robustly(P<0.01),and TLR4 in cytoplasm was found to co-lo-cate with EEA1. When the stimulation reached 90 minutes and 180 minutes,the fluorescence intensity of TLR4 in both cytomembrane and cytoplasm decreased obviously (P<0.01),and the co-location with EEA1 was attenuated present (P<0.01). In the rest state,the fluorescence intensity of the downstream molecule p65 and IRF3 was al-most totally in the cytoplasm. After the stimulation of LPS, fluorescence intensity both in nucleus was increased gradually (P<0.05),but the fluorescence intensity of p65 in nucleus was enhanced earlier and lasted longer than that of IRF3. The phosphorylation of p65 was also earlier and lasted longer than that of IRF3. Conclusions The changed location of TLR4 after being activated can make the transfer time of IRF3 pathway longer and the lasting time shorter than that of NF-κB robustly.

RIG-I-like receptor-induced IRF3 mediated pathway of apoptosis (RIPA): a new antiviral pathway

The innate immune response is the first line of host defense to eliminate viral infection. Pattern recognition receptors in the cytosol, such as RIG-I-like receptors (RLR) and Nod-like receptors (NLR), and membrane bound Toll like receptors (TLR) detect viral infection and initiate transcription of a cohort of antiviral genes, including interferon (IFN) and interferon stimulated genes (ISGs), which ultimately block viral replication. Another mechanism to reduce viral spread is through RIPA, the RLR-induced IRF3-mediated pathway of apoptosis, which causes infected cells to undergo premature death. The transcription factor IRF3 can mediate cellular antiviral responses by both inducing antiviral genes and triggering apoptosis through the activation of RIPA. The mechanism of IRF3 activation in RIPA is distinct from that of transcriptional activation; it requires linear polyubiquitination of specific lysine residues of IRF3. Using RIPA-active, but transcriptionally inactive, IRF3 mutants, it was shown that RIPA can prevent viral replication and pathogenesis in mice.

Effects of IRF3 gene interference on dynamic changes of cytokine secretions in early of LPS stimulation in primary Kupffer cells / 中国免疫学杂志

Objective:To investigate the effects of IRF 3 shRNA adenovirus on dynamic changes of early cytokines in LPS-stimulated primary Kupffer cells ( KCs ).Methods: Rat KCs were isolated and purified by means of in situ perfusion.After being infected with adenovirus carrying IRF 3 shRNA for 48 h, KCs were stimulated with LPS.Cell culture supernatants were collected respectively at 0,2,4 and 6 h after LPS stimulation as well as cells at 6 h.Supernatant cytokine secretion levels were detected by enzyme-linked immunosorbent assay ( ELISA).Intracellular gene expressions were tested by RT-PCR and Westeron blot.Results:IRF3 mRNA and protein were induced by LPS ,but suppressed by IRF 3 shRNA adenovirus in LPS-stimulated or non-stimulated KCs.IFN-βsecretions rose in the very early stage ( at 2 h) ,reached the peak at 4 h,and began to reduce but still remained high levels at 6 h after LPS stimulation in KCs.Interference adenovirus pretreatment suppressed IFN-βsecretions ( especially the secretion peak ) at each time point after LPS stimulation.IFN-βsecretions reached normal levels at 6 h after the stimulation in adenovirus-pretreated cells;TNF-αse-cretions rapidly increased in the very early stage and reached the peak at 2 h,then began to decrease gradually ,but remained high levels at 6 h after LPS stimulation in KCs.Interference adenovirus pretreatment inhibited LPS-induced TNF-αsecretions, especially the secretion peak;IL-1βsecretions did not increase untill 4 h, but reached a higher level at 6 h after LPS stimulation.Interference adenovirus suppressed IL-1βsecretions in the early stage of LPS stimulation;IL-10 secretions began to rise in the very early stage ,and gradually increased over time after LPS stimulation in KCs.Pretreatment of adenovirus with IRF 3 shRNA promoted upregulations of IL-10 secretions at each time point of the early of LPS stimulation.Conclusion:IRF3 gene expression can be silenced by IRF 3 shRNA ad-enovirus.IRF3 can promote its downstream signaling molecule IFN-βand pro-inflammatory cytokines including TNF-αand IL-1β,and block anti-inflammation cytokine IL-10 secretions in LPS-stimulated primary KCs.Therefore,IRF3 may play a central role in immune inflammatory injury of liver tissues.

Effects of inhibited expression of IRF3 in LPS-stimulated Kupffer cells on the activation of signal transduction pathways / 中华微生物学和免疫学杂志

Objective To investigate the effects of interferon regulator factor 3 (IRF3) shRNA on the expression of TLR4 downstream signal molecules including IRF3-IFN-β, NF-κB/p38 MAPK-TNF-α/IL-1βand IL-10 in lipopolysaccharide (LPS)-stimulated Kupffer cells (KCs). Methods KCs were isolated from rats by in situ perfusion. The adenovirus strains carrying IRF3 shRNA were used for the transfection of purified KCs. The isolated KCs were randomly divided into four groups including adenovirus(-) LPS(-) treatment group, adenovirus(-) LPS(+) treatment group, adenovirus(+) LPS(-) treatment group and ad-enovirus(+) LPS(+) treatment group. The levels of cytokines in the supernatants of KC culture were detec-ted by enzyme-linked immunosorbent assay ( ELISA ) . Real-time PCR and Western blot assay were per-formed to analyze the expression of related cytokines at mRNA and protein levels, respectively. Results The expression of IRF3 at mRNA and protein levels in primary cultured KCs were induced by LPS. The cel-lular constitutive expression of IRF3 at mRNA level and the LPS-induced expression of IRF3 were signifi-cantly inhibited after transfection of KCs with adenovirus strains carrying IRF3 shRNA. However, the nucle-ar constitutive expression of IRF3 protein was not affected by IRF3 shRNA. The expression of IFN-βat mR-NA and protein levels in KCs were induced by LPS, but were suppressed by the interference with IRF3 shR-NA. No significant changes of the cellular constitutive expression of IFN-βat mRNA and protein levels were observed in IRF3 shRNA-treated KCs. Enhanced expression of proinflammatory cytokines including TNF-αand IL-1β at mRNA and protein levels were detected in LPS-stimulated KCs. Transfection of KCs with ade-novirus strains carrying IRF3 shRNA inhibited the LPS-induced secretion of TNF-α and IL-1β, but neither LPS-induced expression of TNF-α and IL-1β at mRNA level nor cellular constitutive expression of TNF-αand IL-1βat mRNA and protein levels were affected by IRF3 shRNA. The LPS-induced expression of IL-10 at mRNA and protein levels were enhanced in IRF3 shRNA-treated KCs. However, the cellular constitutive expression of IL-10 at mRNA and protein levels were not affected by the adenovirus. The levels of phosphor-NF-κB p65 subunit and phosphor-p38 MAPK protein in the nuclei of KCs were increased upon the stimula-tion with LPS. Treatment of KCs with IRF3 shRNA showed no significant effects on nuclear phosphor-NF-κB p65 subunit and phosphor-p38 MAPK. Conclusion Transfection of LPS-stimulated primary KCs with ade-novirus strains carrying IRF3 shRNA could effectively inhibit the expression of IRF3 and the transduction of downstream signals. IRF3 enhanced the secretion of TNF-αand IL-1β, but inhibited the expression of IL-10 in LPS-treated KCs. The LPS-induced activation of NF-κB and p38 MAPK in KCs were not affected by IRF3 signal.

Roles of UⅡ/UT system played in innate immune inflammatory signal pathway TLR4-IRF3 in LPS-stimulated primary Kupffer cells / 中国免疫学杂志

Objecitve:To investigate effects of urotensin Ⅱ( UⅡ)/UT system on innate immune inflammatory signal pathway TLR4-IRF3 in the lipopolysaccharide (LPS)-stimulated Kupffer cells (KCs).Methods: Rat KCs were isolated and cultured.Pro-in-flammatory cytokines including IL-6,IFN-βand IFN-γwere assayed by ELISA in culture supernatant of KCs.Cell surface TLR4 were tested with flow cytometry technique.Expression of IRF3 were tested with real-time PCR and Western blot.Results: Significant increases were showed in IL-6, IFN-βand IFN-γsecretion, TLR4-expressed positive rates and IRF3 mRNA levels in KCs after stimulated by LPS,but were inhibited via urantide pretreatment.In addition,LPS induced upregulation of nuclear IRF3 protein and downregulation of cytoplasm IRF3 protein in KCs,which were blocked by urantide pretreatment.Conclusion:UⅡ/UT system mediates immune inflammatory response in part through activating TLR 4-IRF3 pathway in LPS-stimulated KCs.

TLR4 mediated the nuclear translocation of transcription factor NF-κB and IRF-3 in HTNV infected vascular endothelial cells / 中华微生物学和免疫学杂志

Objective To observe the nuclear translocation of transcription factor NF-κB and IRF-3 in TLR4 silenced EVC304 cells infected by HTNV and to provide new information for anti-HTNV innate immunity and its signal transduction. Methods TLR4~- cells and TLR4~+ cells were infected by HTNV 76-118, respectively. The cells stimulated by LPS were selected as positive control groups, and the cells without stimulation were selected as negative control groups. After 6 hours, indirect immunofluorescence assay(IFA) was used to detect the nuclear translocation of NF-κB and IRF-3. Results The transcription factor NF-κB and IRF-3 transfered into nuclear 6 hours after stimulated by HTNV 76-118. Conclusion TLR4 may mediate the nuclear translocation of transcription factor NF-κB and IRF-3 in HTNV infected human umbilical vein endothelial cells.

Characterization of promoter of human interferon regulatory factor 3 / 中华微生物学和免疫学杂志

ays revealed that the-(167-111)bp region Was the minimal promoter of the human IRF3 gene.These results suggested that transcriptional factors such ag E2F might be involved in the transcriptional regulation of IRF3 gene.

Interferon-Stimulated Genes Response in Endothelial Cells Following Hantaan Virus Infection

The regulation mechanism of interferon (IFN) and IFN-stimulated genes is a very complex procedure and is dependent on cell types and virus species. We observed molecular changes related to anti-viral responses in endothelial cells during Hantaan virus (HTNV) infection. We found that there are two patterns of gene expression, the first pattern of gene expression being characterized by early induction and short action, as in that of type I IFNs,' and the other being characterized by delayed induction and long duration, as those of IRF-7, MxA, and TAP-1/2. Even though there are significant differences in their induction folds, we found that all of IFN-alpha/beta , IRF- 3/7, MxA, and TAP-1/2 mRNA expressions reached the peak when the viral replication was most active, which took place 3 days of post infection (d.p.i.). In addition, an interesting phenomenon was observed; only one gene was highly expressed in paired genes such as IFN-alpha/beta??(3/277-folds), IRF-3/7 (2.2/29.4-folds), and TAP- 1/2 (26.2/6.1-folds). Therefore, IFN-beta, IRF-7, and TAP-1 seem to be more important for the anti-viral response in HTNV infection. MxA was increased to 296-folds at 3 d.p.i. and kept continuing 207-folds until 7 d.p.i.. The above results indicate that IFN-beta works for an early anti-viral response, while IRF7, MxA, and TAP-1 work for prolonged anti-viral response in HTNV infection.

The Effect of Toll-like Receptor 4(TLR4) on Expression of IRF-3 and IFN-? During Cerebral Ischemia Reperfusion in Hippocampus in Mice / 医学研究杂志

Objective To study the effect of Toll-like receptor 4(TLR4)on expression of IRF-3 and IFN-? during the inflammatory reaction induced by cerebral ischemia reperfusion in mice. Methods After blockade of TLR4 by TLR4 antibody,expression of TLR4,IRF-3 and IFN-? at the protein level in hippocampus was examined by Western blot,respectively. Mice were randomly divided into sham group,ischemia reperfusion group and TLR4 blocking group in different time points (1,2,3 and 4 day). Results In the right cortex,the expression of TLR4,IRF-3 and IFN-? of I group was distinctly higher than that of S and T group(P