The IRF1/GBP5 axis promotes osteoarthritis progression by activating chondrocyte pyroptosis.
Journal of orthopaedic translation
Background:Osteoarthritis (OA) is a chronic degenerative joint disease that primarily affects middle-aged and elderly individuals. The decline in chondrocyte function plays a crucial role in the development of OA. Inflammasome-mediated chondrocyte pyroptosis is implicated in matrix degradation and cartilage degeneration in OA patients. Guanylate binding protein 5 (GBP5), a member of the GTPase family induced by Interferon-γ (IFN-γ), significantly influences cellular inflammatory responses, including intracellular inflammasome activation and cytokine release. However, the role of GBP5 in chondrocyte pyroptosis and OA progression remains unclear. Methods:In this study, we used tumor necrosis factor-α (TNF-α) to induce inflammation and created an OA mouse model with surgically-induced destabilization of the medial meniscus (DMM). We isolated and cultured primary chondrocytes from the knee joints of suckling C57 mice. TNF-α-stimulated primary chondrocytes served as an in vitro model for OA and underwent RNA sequencing. Chondrocytes were transfected with GBP5-overexpression plasmids and small interfering RNA and were subsequently treated with TNF-α. We assessed the expression of cartilage matrix components (COL2A1 and aggrecan), catabolic factors (MMP9 and MMP13), and NLRP3 inflammasome pathway genes (NLRP3, Caspase1, GSDMD, Pro-IL-1β, and Pro-Caspase1) using RT-qPCR and Western blotting. We analyzed the expression of GBP5, NLRP3, and Caspase1 in the cartilage of DMM-induced post-traumatic OA mice and human OA patients. Immunohistochemistry (IHC) was used to detect the expression of GBP5, NLRP3 and GSDMD in cartilage specimens from OA patients and mouse DMM models. Chondrocyte pyroptosis was assessed using flow cytometry, and the levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18) were measured with ELISA. We conducted double luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays to confirm the relationship between IRF1 and GBP5. Results:GBP5 expression increased in TNF-α-induced chondrocytes, as revealed by RNA sequencing. GBP5 inhibited COL2A1 and aggrecan expression while promoting the expression of MMP9, MMP13, NLRP3, Caspase1, GSDMD, Pro-IL-1β, and Pro-Caspase1. GBP5 expression also increased in the cartilage of DMM-induced post-traumatic OA mice and human OA patients. Knockout of GBP5 reduced chondrocyte injury in OA mice. GBP5 promoted chondrocyte pyroptosis and the production of IL-1β and IL-18. Additionally, we found that IRF1 bound to the promoter region of GBP5, enhancing its expression. After co-transfected with ad-IRF1 and siGBP5, the expression of pyroptosis-related genes was significantly decreased compared with ad-IRF1 group. Conclusions:The IRF1/GBP5 axis enhances extracellular matrix (ECM) degradation and promotes pyroptosis during OA development, through the NLRP3 inflammasome signaling pathway. The translational potential of this article:This study underscores the significance of the IRF1/GBP5 axis in NLRP3 inflammasome-mediated chondrocyte pyroptosis and osteoarthritic chondrocyte injury. Modulating IRF1 and GBP5 expression could serve as a novel therapeutic target for OA.
10.1016/j.jot.2023.11.005
GBP5 exacerbates rosacea-like skin inflammation by skewing macrophage polarization towards M1 phenotype through the NF-κB signalling pathway.
Journal of the European Academy of Dermatology and Venereology : JEADV
BACKGROUND:Rosacea is a chronic inflammatory skin disease with increased macrophage infiltration. However, the molecular mechanism remains unclear. OBJECTIVES:To determine the significance of macrophage infiltration, and the correlation between Guanylate-binding protein 5 (GBP5) and polarization of macrophages in rosacea-like inflammation. METHODS:Here we tested the hypothesis that Guanylate-binding protein 5 (GBP5) aggravates rosacea-like skin inflammation by promoting the polarization of the M1 macrophages through the NF-κB signalling pathway. We depleted macrophage by injecting clodronate-containing liposomes. We next explored the association between GBP5 and macrophage in rosacea tissue through transcriptome analysis and immunofluorescence analysis. We evaluated the severity of rosacea-like skin inflammation when BALB/c mice were injected with GBP5 siRNA intradermally daily for three consecutive days. At last, to study the causality of knocking down GBP5-blunted M1 macrophage polarization, THP-1 cell was treated with GBP5 siRNA. RESULTS:Macrophage depletion ameliorated rosacea-like skin inflammation in mice, implying the important role of macrophages in rosacea. Based on the transcriptome analysis, Guanylate-binding protein 5 (GBP5) was identified as hub gene that was associated with macrophage infiltration in rosacea. Next, we found that GBP5 expression was significantly upregulated in rosacea tissues and positively correlated with macrophage infiltration, the immunofluorescence analysis revealed the co-localization between GBP5 and macrophages. In vivo, silencing of GBP5 attenuated rosacea-like skin inflammation in the LL-37-induced mouse model and suppressed the expression of M1 signature genes such as IL-6, iNOS and TNF-a. In vitro, knocking down GBP5 significantly blunted the polarization of the M1 macrophages partly by repressing the activation of the NF-κB signalling pathways. CONCLUSIONS:Together, our study revealed the important role of macrophages in rosacea and identified GBP5 as a key regulator of rosacea by inducing M1 macrophage polarization via NF-κB signalling pathways.
10.1111/jdv.18725
Guanylate-Binding Proteins 2 and 5 Exert Broad Antiviral Activity by Inhibiting Furin-Mediated Processing of Viral Envelope Proteins.
Braun Elisabeth,Hotter Dominik,Koepke Lennart,Zech Fabian,Groß Rüdiger,Sparrer Konstantin M J,Müller Janis A,Pfaller Christian K,Heusinger Elena,Wombacher Rebecka,Sutter Kathrin,Dittmer Ulf,Winkler Michael,Simmons Graham,Jakobsen Martin R,Conzelmann Karl-Klaus,Pöhlmann Stefan,Münch Jan,Fackler Oliver T,Kirchhoff Frank,Sauter Daniel
Cell reports
Guanylate-binding protein (GBP) 5 is an interferon (IFN)-inducible cellular factor reducing HIV-1 infectivity by an incompletely understood mechanism. Here, we show that this activity is shared by GBP2, but not by other members of the human GBP family. GBP2/5 decrease the activity of the cellular proprotein convertase furin, which mediates conversion of the HIV-1 envelope protein (Env) precursor gp160 into mature gp120 and gp41. Because this process primes HIV-1 Env for membrane fusion, viral particles produced in the presence of GBP2/5 are poorly infectious due to increased incorporation of non-functional gp160. Furin activity is critical for the processing of envelope glycoproteins of many viral pathogens. Consistently, GBP2/5 also inhibit Zika, measles, and influenza A virus replication and decrease infectivity of viral particles carrying glycoproteins of Marburg and murine leukemia viruses. Collectively, our results show that GPB2/5 exert broad antiviral activity by suppressing the activity of the virus-dependency factor furin.
10.1016/j.celrep.2019.04.063
Guanylate Binding Protein (GBP) 5 Is an Interferon-Inducible Inhibitor of HIV-1 Infectivity.
Krapp Christian,Hotter Dominik,Gawanbacht Ali,McLaren Paul J,Kluge Silvia F,Stürzel Christina M,Mack Katharina,Reith Elisabeth,Engelhart Susanne,Ciuffi Angela,Hornung Veit,Sauter Daniel,Telenti Amalio,Kirchhoff Frank
Cell host & microbe
Guanylate binding proteins (GBPs) are an interferon (IFN)-inducible subfamily of guanosine triphosphatases (GTPases) with well-established activity against intracellular bacteria and parasites. Here we show that GBP5 potently restricts HIV-1 and other retroviruses. GBP5 is expressed in the primary target cells of HIV-1, where it impairs viral infectivity by interfering with the processing and virion incorporation of the viral envelope glycoprotein (Env). GBP5 levels in macrophages determine and inversely correlate with infectious HIV-1 yield over several orders of magnitude, which may explain the high donor variability in macrophage susceptibility to HIV. Antiviral activity requires Golgi localization of GBP5, but not its GTPase activity. Start codon mutations in the accessory vpu gene from macrophage-tropic HIV-1 strains conferred partial resistance to GBP5 inhibition by increasing Env expression. Our results identify GBP5 as an antiviral effector of the IFN response and may explain the increased frequency of defective vpu genes in primary HIV-1 strains.
10.1016/j.chom.2016.02.019
The XPO1 inhibitor selinexor ameliorates bleomycin-induced pulmonary fibrosis in mice via GBP5/NLRP3 inflammasome signaling.
International immunopharmacology
Pulmonary fibrosis is an irreversible and progressive lung disease with limited treatments available. Selinexor (Sel), an orally available, small-molecule, selective inhibitor of XPO1, exhibits notable antitumor, anti-inflammatory and antiviral activities. However, its potential role in treating pulmonary fibrosis is unknown. C57BL/6J mice were used to establish a pulmonary fibrosis model by intratracheal administration of bleomycin (BLM). Subsequently, Sel was administered intraperitoneally. Our data demonstrated that Sel administration ameliorated BLM-induced pulmonary fibrosis by increasing mouse body weights; reducing H&E staining, Masson staining scores, and shadows in mouse lung computed tomography (CT) images, decreasing the total cell and neutrophil counts in the lung and bronchoalveolar lavage fluid (BALF); and decreasing the levels of TGF-β1. We next confirmed that Sel reduced the deposition of extracellular matrix (ECM) components in the lungs of BLM-induced pulmonary fibrosis mice. We showed that collagen I, alpha-smooth muscle actin (α-SMA), and hydroxyproline levels and the mRNA levels of Col1a1, Eln, Fn1, Ctgf, and Fgf2 were reduced. Mechanistically, tandem mass tags (TMT)- based quantitative proteomics analysis revealed a significant increase in GBP5 in the lungs of BLM mice but a decrease in that of BLM + Sel mice; this phenomenon was confirmed by western blotting and RT-qPCR. NLRP3 inflammasome signaling was significantly enriched in both the BLM group and BLM + Sel group based on GO and KEGG analyses of differentially expressed proteins between the groups. Furthermore, Sel reduced the expression of NLRP3, cleaved caspase 1, and ASC in vivo and in vitro, and decreased the levels of IL-1β, IL-18, and IFN-r in lung tissue and BALF. SiRNA-GBP5 inhibited NLRP3 signaling in vitro, and overexpression of GBP5 inhibited the protective effect of Sel against BLM-induced cellular injury. Taken together, our findings indicate that Sel ameliorates BLM-induced pulmonary fibrosis by targeting GBP5 via NLRP3 inflammasome signaling. Thus, the XPO1 inhibitor - Sel might be a potential therapeutic agent for pulmonary fibrosis.
10.1016/j.intimp.2024.111734
Structural basis for GTP-induced dimerization and antiviral function of guanylate-binding proteins.
Cui Wen,Braun Elisabeth,Wang Wei,Tang Jinhong,Zheng Yanyan,Slater Benjamin,Li Na,Chen Cheng,Liu Qingxiang,Wang Bin,Li Xiu,Duan Yinkai,Xiao Yunjie,Ti Ruijiao,Hotter Dominik,Ji Xiaoyun,Zhang Lei,Cui Jun,Xiong Yong,Sauter Daniel,Wang Zefang,Kirchhoff Frank,Yang Haitao
Proceedings of the National Academy of Sciences of the United States of America
Guanylate-binding proteins (GBPs) form a family of dynamin-related large GTPases which mediate important innate immune functions. They were proposed to form oligomers upon GTP binding/hydrolysis, but the molecular mechanisms remain elusive. Here, we present crystal structures of C-terminally truncated human GBP5 (hGBP5), comprising the large GTPase (LG) and middle (MD) domains, in both its nucleotide-free monomeric and nucleotide-bound dimeric states, together with nucleotide-free full-length human GBP2. Upon GTP-loading, hGBP5 forms a closed face-to-face dimer. The MD of hGBP5 undergoes a drastic movement relative to its LG domain and forms extensive interactions with the LG domain and MD of the pairing molecule. Disrupting the MD interface (for hGBP5) or mutating the hinge region (for hGBP2/5) impairs their ability to inhibit HIV-1. Our results point to a GTP-induced dimerization mode that is likely conserved among all GBP members and provide insights into the molecular determinants of their antiviral function.
10.1073/pnas.2022269118
Guanylate-binding protein 5 antagonizes viral glycoproteins independently of furin processing.
mBio
Guanylate-binding protein (GBP) 5 is an interferon-inducible cellular factor with broad anti-viral activity. Recently, GBP5 has been shown to antagonize the glycoproteins of a number of enveloped viruses, in part by disrupting the host enzyme furin. Here we show that GBP5 strongly impairs the infectivity of virus particles bearing not only viral glycoproteins that depend on furin cleavage for infectivity-the envelope (Env) glycoproteins of HIV-1 and murine leukemia virus and the spike (S) glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-but also viral glycoproteins that do not depend on furin cleavage: vesicular stomatitis virus glycoprotein and SARS-CoV S. We observe that GBP5 disrupts proper -linked protein glycosylation and reduces the incorporation of viral glycoproteins into virus particles. The glycosylation of the cellular protein CD4 is also altered by GBP5 expression. Flow cytometry analysis shows that GBP5 expression reduces the cell-surface levels of HIV-1 Env and the S glycoproteins of SARS-CoV and SARS-CoV-2. Our data demonstrate that, under the experimental conditions used, inhibition of furin-mediated glycoprotein cleavage is not the primary anti-viral mechanism of action of GBP5. Rather, the antagonism appears to be related to impaired trafficking of glycoproteins to the plasma membrane. These results provide novel insights into the broad antagonism of viral glycoprotein function by the cellular host innate immune response. IMPORTANCE:The surface of enveloped viruses contains viral envelope glycoproteins, an important structural component facilitating virus attachment and entry while also acting as targets for the host adaptive immune system. In this study, we show that expression of GBP5 in virus-producer cells alters the glycosylation, cell-surface expression, and virion incorporation of viral glycoproteins across several virus families. This research provides novel insights into the broad impact of the host cell anti-viral factor GBP5 on protein glycosylation and trafficking.
10.1128/mbio.02086-24
GBP5 promotes NLRP3 inflammasome assembly and immunity in mammals.
Shenoy Avinash R,Wellington David A,Kumar Pradeep,Kassa Hilina,Booth Carmen J,Cresswell Peter,MacMicking John D
Science (New York, N.Y.)
Inflammasomes are sensory complexes that alert the immune system to the presence of infection or tissue damage. These complexes assemble NLR (nucleotide binding and oligomerization, leucine-rich repeat) or ALR (absent in melanoma 2-like receptor) proteins to activate caspase-1 cleavage and interleukin (IL)-1β/IL-18 secretion. Here, we identified a non-NLR/ALR human protein that stimulates inflammasome assembly: guanylate binding protein 5 (GBP5). GBP5 promoted selective NLRP3 inflammasome responses to pathogenic bacteria and soluble but not crystalline inflammasome priming agents. Generation of Gbp5(-/-) mice revealed pronounced caspase-1 and IL-1β/IL-18 cleavage defects in vitro and impaired host defense and Nlrp3-dependent inflammatory responses in vivo. Thus, GBP5 serves as a unique rheostat for NLRP3 inflammasome activation and extends our understanding of the inflammasome complex beyond its core machinery.
10.1126/science.1217141