scholarly journals Ubiquitination of TLR3 by TRIM3 signals its ESCRT-mediated trafficking to the endolysosomes for innate antiviral response

2020 ◽  
Vol 117 (38) ◽  
pp. 23707-23716
Author(s):  
Wei-Wei Li ◽  
Ying Nie ◽  
Yan Yang ◽  
Yong Ran ◽  
Wei-Wei Luo ◽  
...  

Trafficking of toll-like receptor 3 (TLR3) from the endoplasmic reticulum (ER) to endolysosomes and its subsequent proteolytic cleavage are required for it to sense viral double-stranded RNA (dsRNA) and trigger antiviral response, yet the underlying mechanisms remain enigmatic. We show that the E3 ubiquitin ligase TRIM3 is mainly located in the Golgi apparatus and transported to the early endosomes upon stimulation with the dsRNA analog poly(I:C). TRIM3 mediates K63-linked polyubiquitination of TLR3 at K831, which is enhanced following poly(I:C) stimulation. The polyubiquitinated TLR3 is recognized and sorted by the ESCRT (endosomal sorting complex required for transport) complexes to endolysosomes. Deficiency of TRIM3 impairs TLR3 trafficking from the Golgi apparatus to endosomes and its subsequent activation.Trim3−/−cells and mice express lower levels of antiviral genes and show lower levels of inflammatory response following poly(I:C) but not lipopolysaccharide (LPS) stimulation. These findings suggest that TRIM3-mediated polyubiquitination of TLR3 represents a feedback-positive regulatory mechanism for TLR3-mediated innate immune and inflammatory responses.

2019 ◽  
Vol 116 (40) ◽  
pp. 20063-20069 ◽  
Author(s):  
Tian Xia ◽  
Xue-Mei Yi ◽  
Xin Wu ◽  
Jun Shang ◽  
Hong-Bing Shu

Upon cytosolic viral DNA stimulation, cGMP-AMP synthase (cGAS) catalyzes synthesis of 2′3′cGMP-AMP (cGAMP), which binds to the adaptor protein MITA (mediator of IRF3 activation, also called STING, stimulator of IFN genes) and induces innate antiviral response. How the activity of MITA/STING is regulated to avoid excessive innate immune response is not fully understood. Here we identified the tyrosine-protein phosphatase nonreceptor type (PTPN) 1 and 2 as MITA/STING-associated proteins. PTPN1 and PTPN2 are associated with MITA/STING following viral infection and dephosphorylate MITA/STING at Y245. Dephosphorylation of MITA/STING leads to its degradation via the ubiquitin-independent 20S proteasomal pathway, which is dependent on the intrinsically disordered region (IDR) of MITA/STING. Deficiencies of PTPN1 and PTPN2 enhance viral DNA-induced transcription of downstream antiviral genes and innate antiviral response. Our findings reveal that PTPN1/2-mediated dephosphorylation of MITA/STING and its degradation by the 20S proteasomal pathway is an important regulatory mechanism of innate immune response to DNA virus.


Genes ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1226
Author(s):  
Hui Huang ◽  
Mona Sharma ◽  
Yanbing Zhang ◽  
Chenxi Li ◽  
Ke Liu ◽  
...  

TRIM26, a member of the tripartite motif (TRIM) family has been shown to be involved in modulation of innate antiviral response. However, the functional characteristics of porcine TRIM26 (porTRIM26) are unclear. In this study, we used a synthesized antigen peptide to generate a polyclonal antibody against porTRIM26 with which to study the expression and function of porTRIM26. We demonstrated that polyinosinic:polycytidylic acid (poly (I:C)) stimulation and viral infection (vesicular stomatitis (VSV) or porcine reproductive and respiratory syndrome virus (PRRSV)) induce expression of porTRIM26, whereas knock-down expression of porTRIM26 promotes interferon (IFN)-β production after poly (I:C) stimulation and virus infection (VSV or PRRSV). The importance of the porTRIM26-mediated modulation of the antiviral response was also shown in VSV- or PRRSV-infected cells. In summary, these findings show that porTRIM26 has an inhibitory role in IFN-β expression and the antiviral response.


Author(s):  
Tatsuro Saruga ◽  
Tadaatsu Imaizumi ◽  
Shogo Kawaguchi ◽  
Kazuhiko Seya ◽  
Tomoh Matsumiya ◽  
...  

AbstractC-X-C motif chemokine 10 (CXCL10) is an inflammatory chemokine and a key molecule in the pathogenesis of rheumatoid arthritis (RA). Melanoma differentiation-associated gene 5 (MDA5) is an RNA helicase that plays a role in innate immune and inflammatory reactions. The details of the regulatory mechanisms of CXCL10 production and the precise role of MDA5 in RA synovitis have not been fully elucidated. The aim of this study was to examine the role of MDA5 in regulating CXCL10 expression in cultured human rheumatoid fibroblast-like synoviocytes (RFLS). RFLS was stimulated with Toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA mimetic. Expression of interferon beta (IFN-β), MDA5, and CXCL10 was measured by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assay. A neutralizing antibody of IFN-β and siRNA-mediated MDA5 knockdown were used to determine the role of these molecules in regulating CXCL10 expression downstream of TLR3 signaling in RFLS. Poly I:C induced IFN-β, MDA5, and CXCL10 expression in a concentration- and time-dependent manner. IFN-β neutralizing antibody suppressed the expression of MDA5 and CXCL10, and knockdown of MDA5 decreased a part of CXCL10 expression (p < 0.001). The TLR3/IFN-β/CXCL10 axis may play a crucial role in the inflammatory responses in RA synovium, and MDA5 may be partially involved in this axis.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zhou Yu ◽  
Xuelian Li ◽  
Mingjin Yang ◽  
Jiaying Huang ◽  
Qian Fang ◽  
...  

AbstractSensing of pathogenic nucleic acids by pattern recognition receptors (PRR) not only initiates anti-microbe defense but causes inflammatory and autoimmune diseases. E3 ubiquitin ligase(s) critical in innate response need to be further identified. Here we report that the tripartite motif-containing E3 ubiquitin ligase TRIM41 is required to innate antiviral response through facilitating pathogenic nucleic acids-triggered signaling pathway. TRIM41 deficiency impairs the production of inflammatory cytokines and type I interferons in macrophages after transfection with nucleic acid-mimics and infection with both DNA and RNA viruses. In vivo, TRIM41 deficiency leads to impaired innate response against viruses. Mechanistically, TRIM41 directly interacts with BCL10 (B cell lymphoma 10), a core component of CARD proteins−BCL10 − MALT1 (CBM) complex, and modifies the Lys63-linked polyubiquitylation of BCL10, which, in turn, hubs NEMO for activation of NF-κB and TANK-binding kinase 1 (TBK1) − interferon regulatory factor 3 (IRF3) pathways. Our study suggests that TRIM41 is the potential universal E3 ubiquitin ligase responsible for Lys63 linkage of BCL10 during innate antiviral response, adding new insight into the molecular mechanism for the control of innate antiviral response.


2021 ◽  
Vol 149 ◽  
pp. 110703
Author(s):  
Juliana Cavalli ◽  
Mariana A. Freitas ◽  
Elaine C.D. Gonçalves ◽  
Guilherme P. Fadanni ◽  
Adara A. Santos ◽  
...  

2016 ◽  
Vol 33 (S1) ◽  
pp. s220-s221
Author(s):  
K. MacDowell ◽  
E. Munarriz-Cuezva ◽  
D. Martín-Hernández ◽  
A. Sayd ◽  
B. García-Bueno ◽  
...  

IntroductionAlterations on the innate inflammatory response may underlie the pathophysiology of psychiatric diseases, but the mechanisms implicated remain elusive. Current antipsychotics modulate pro/anti-inflammatory pathways, but the specific mechanisms involved remain elusive. One attractive possibility is the regulation of the intracellular signalling pathways of the innate immune receptors Toll-like 3 (TLR3), which triggers antiviral and inflammatory responses.AimsTo elucidate the regulatory role of paliperidone on maternal immune activation (MIA) induced alterations on TLR3 pathway and on the two emerging endogenous antiinflammatory/antioxidant mechanisms NRF2/antioxidant enzymes pathway and the cytokine milieu regulating M1/M2 polarization in microglia.MethodsPregnant mice were treated with the synthetic Toll-like Receptor 3 (TLR3) agonist Poly(I:C) in gestational day 9 and chronically treated with paliperidone (0,05 mg/kg i.p.) in adult offspring. Animals were sacrificed one day after treatment and behavioral test. Inflammation oxidative stress-related mediators were analysed at mRNA and protein level in prefrontal cortex samples. In addition, behavioral test t-maze was conducted.ResultsPaliperidone prevented TLR3 pathway activation and the subsequent MIA-induced neuroinflammatory response. Also, paliperidone induced an increment in the activity and protein expression of nuclear NRF2, as well as increased mRNA levels of the antioxidant enzymes HO1, SOD and catalase in the MIA model. Otherwise, paliperidone increases the antiinflammatory cytokines levels TGFβ and IL-10 in favour of a M2 microglia profile and increased the levels of the M2 cellular markers ArgI and FOLR2.ConclusionsThe modulation of neuroinflammation and enhancement of endogenous antioxidant/anti-inflammatory pathways by current and new antipsychotics could represent an interesting therapeutic strategy for the future.Disclosure of interestThe authors have not supplied their declaration of competing interest.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jamie Francisco ◽  
Yu Zhang ◽  
Yasuki Nakada ◽  
Jae Im Jeong ◽  
Chun-Yang Huang ◽  
...  

AbstractFibrosis is a hallmark of heart disease independent of etiology and is thought to contribute to impaired cardiac dysfunction and development of heart failure. However, the underlying mechanisms that regulate the differentiation of fibroblasts to myofibroblasts and fibrotic responses remain incompletely defined. As a result, effective treatments to mitigate excessive fibrosis are lacking. We recently demonstrated that the Hippo pathway effector Yes-associated protein (YAP) is an important mediator of myofibroblast differentiation and fibrosis in the infarcted heart. Yet, whether YAP activation in cardiac fibroblasts is sufficient to drive fibrosis, and how fibroblast YAP affects myocardial inflammation, a significant component of adverse cardiac remodeling, are largely unknown. In this study, we leveraged adeno-associated virus (AAV) to target cardiac fibroblasts and demonstrate that chronic YAP expression upregulated indices of fibrosis and inflammation in the absence of additional stress. YAP occupied the Ccl2 gene and promoted Ccl2 expression, which was associated with increased macrophage infiltration, pro-inflammatory cytokine expression, collagen deposition, and cardiac dysfunction in mice with cardiac fibroblast-targeted YAP overexpression. These results are consistent with other recent reports and extend our understanding of YAP function in modulating fibrotic and inflammatory responses in the heart.


2019 ◽  
Vol 5 (5) ◽  
pp. eaav5562 ◽  
Author(s):  
Ruochan Chen ◽  
Ling Zeng ◽  
Shan Zhu ◽  
Jiao Liu ◽  
Herbert J. Zeh ◽  
...  

The ability of cytosolic lipopolysaccharide (LPS) to activate caspase-11–dependent nonclassical inflammasome is intricately controlled to avoid excessive inflammatory responses. However, very little is known about the regulatory role of various metabolic pathways in the control of caspase-11 activation. Here, we demonstrate that l-adrenaline can act on receptor ADRA2B to inhibit the activation of the caspase-11 inflammasome by cytosolic LPS or Escherichia coli infection in macrophages. l-adrenaline–induced cAMP production via the enzyme ADCY4 promotes protein kinase A (PKA) activation, which then blocks the caspase-11–mediated proteolytic maturation of interleukin-1β, gasdermin D (GSDMD) cleavage, and consequent DAMP release. Inhibition of PDE8A-mediated cAMP hydrolysis limits caspase-11 inflammasome activation and pyroptosis in macrophages. Consequently, pharmacological modulation of the ADRA2B-ADCY4-PDE8A-PKA axis, knockout of caspase-11 (Casp11−/−), or Gsdmd inactivation (GsdmdI105N/I105N) similarly protects against LPS-induced lethality in poly(I:C)-primed mice. Our results provide previously unidentified mechanistic insight into immune regulation by cAMP and represent a proof of concept that immunometabolism constitutes a potential therapeutic target in sepsis.


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