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Mesenchymal stem cells detect and defend against gammaherpesvirus infection via the cGAS-STING pathway.

Yang K, Wang J, Wu M, Li M, Wang Y, Huang X - Sci Rep (2015)

Bottom Line: Cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) was identified as the sensor of MHV-68 in MSCs for the first time.Moreover, the cytosolic DNA sensing pathway mediated a potent anti-herpesviral effect through the adaptor STING and downstream kinase TBK1.Furthermore, blockade of IFN signaling suggested that cytosolic DNA sensing triggered both IFN-dependent and -independent anti-herpesviral responses.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China [2] Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China.

ABSTRACT
Mesenchymal stem cells (MSCs) are widely used in clinical settings to treat tissue injuries and autoimmune disorders due to their multipotentiality and immunomodulation. Long-term observations reveal several complications after MSCs infusion, especially herpesviral infection. However, the mechanism of host defense against herpesviruses in MSCs remains largely unknown. Here we showed that murine gammaherpesvirus-68 (MHV-68), which is genetically and biologically related to human gammaherpesviruses, efficiently infected MSCs both in vitro and in vivo. Cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) was identified as the sensor of MHV-68 in MSCs for the first time. Moreover, the cytosolic DNA sensing pathway mediated a potent anti-herpesviral effect through the adaptor STING and downstream kinase TBK1. Furthermore, blockade of IFN signaling suggested that cytosolic DNA sensing triggered both IFN-dependent and -independent anti-herpesviral responses. Our findings demonstrate that cGAS-STING mediates innate immunity to gammaherpesvirus infection in MSCs, which may provide a clue to develop therapeutic strategy.

No MeSH data available.


Related in: MedlinePlus

Cytosolic DNA sensing pathway mediates both IFN-dependent and -independent antiviral responses.MSCs were pretreated with JAK inhibitor Ruxolitinib (Rux) for 1 hr, then transfected with poly(dA:dT) (0.5 μg/ml), followed by MHV-68 infection (MOI 0.1). The phosphorylation of STAT1 was examined by Western blot at 2 hr post-tranfection (a). The replication of viral DNA was detected by real-time PCR at 6 hr post-infection (b). The virus titers in supernatant were determined by plaque assay at 24 hr post-infection (c). The mRNA expressions of selected ISGs were analyzed by real-time PCR at 6 hr post-tranfection (d). Data are shown as mean ± SEM of three independent experiments. **, p < 0.01; ***, p < 0.001.
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f5: Cytosolic DNA sensing pathway mediates both IFN-dependent and -independent antiviral responses.MSCs were pretreated with JAK inhibitor Ruxolitinib (Rux) for 1 hr, then transfected with poly(dA:dT) (0.5 μg/ml), followed by MHV-68 infection (MOI 0.1). The phosphorylation of STAT1 was examined by Western blot at 2 hr post-tranfection (a). The replication of viral DNA was detected by real-time PCR at 6 hr post-infection (b). The virus titers in supernatant were determined by plaque assay at 24 hr post-infection (c). The mRNA expressions of selected ISGs were analyzed by real-time PCR at 6 hr post-tranfection (d). Data are shown as mean ± SEM of three independent experiments. **, p < 0.01; ***, p < 0.001.

Mentions: Activation of STING-TBK1 signaling axis after cytosolic dsDNA stimulation leads to the production of type I IFNs, which initiate an innate antiviral response by inducing hundreds of ISGs through the JAK-STAT pathway. To determine whether cytosolic DNA sensing-mediated antiviral effect depended on an autocrine effect of type I IFNs, JAK inhibitor Ruxolitinib was used to block IFN-JAK-STAT signaling in dsDNA-stimulated MSCs. Western blot showed that at the concentration of 1.0 μM, Ruxolitinib almost completely blocked dsDNA-induced phosphorylation of STAT1 downstream of IFN-JAK-STAT pathway (Fig. 5a). Furthermore, we found that blocking of the JAK-STAT pathway partially reduced the DNA sensing-mediated antiviral activity, as indicated by both viral DNA (Fig. 5b) and plaque assay data (Fig. 5c). These results suggest that the DNA-sensing pathway could mediate antiviral effects in the absence of canonical IFN-JAK-STAT signaling. Moreover, we examined whether the DNA-sensing pathway can mediate antiviral ISGs expression independently of IFN signaling. Real-time PCR data showed that when IFN-JAK-STAT pathway was blocked by Ruxolitinib, transfection with poly(dA:dT) still induced expressions of ISGs, including IFIT1-3, ISG15 and Mx1, though the expression levels were lower than that in MSCs without Ruxolitinib treatment (Fig. 5d). Together, these data imply that cytosolic DNA sensing mediated both IFN-dependent and -independent antiviral effects.


Mesenchymal stem cells detect and defend against gammaherpesvirus infection via the cGAS-STING pathway.

Yang K, Wang J, Wu M, Li M, Wang Y, Huang X - Sci Rep (2015)

Cytosolic DNA sensing pathway mediates both IFN-dependent and -independent antiviral responses.MSCs were pretreated with JAK inhibitor Ruxolitinib (Rux) for 1 hr, then transfected with poly(dA:dT) (0.5 μg/ml), followed by MHV-68 infection (MOI 0.1). The phosphorylation of STAT1 was examined by Western blot at 2 hr post-tranfection (a). The replication of viral DNA was detected by real-time PCR at 6 hr post-infection (b). The virus titers in supernatant were determined by plaque assay at 24 hr post-infection (c). The mRNA expressions of selected ISGs were analyzed by real-time PCR at 6 hr post-tranfection (d). Data are shown as mean ± SEM of three independent experiments. **, p < 0.01; ***, p < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296288&req=5

f5: Cytosolic DNA sensing pathway mediates both IFN-dependent and -independent antiviral responses.MSCs were pretreated with JAK inhibitor Ruxolitinib (Rux) for 1 hr, then transfected with poly(dA:dT) (0.5 μg/ml), followed by MHV-68 infection (MOI 0.1). The phosphorylation of STAT1 was examined by Western blot at 2 hr post-tranfection (a). The replication of viral DNA was detected by real-time PCR at 6 hr post-infection (b). The virus titers in supernatant were determined by plaque assay at 24 hr post-infection (c). The mRNA expressions of selected ISGs were analyzed by real-time PCR at 6 hr post-tranfection (d). Data are shown as mean ± SEM of three independent experiments. **, p < 0.01; ***, p < 0.001.
Mentions: Activation of STING-TBK1 signaling axis after cytosolic dsDNA stimulation leads to the production of type I IFNs, which initiate an innate antiviral response by inducing hundreds of ISGs through the JAK-STAT pathway. To determine whether cytosolic DNA sensing-mediated antiviral effect depended on an autocrine effect of type I IFNs, JAK inhibitor Ruxolitinib was used to block IFN-JAK-STAT signaling in dsDNA-stimulated MSCs. Western blot showed that at the concentration of 1.0 μM, Ruxolitinib almost completely blocked dsDNA-induced phosphorylation of STAT1 downstream of IFN-JAK-STAT pathway (Fig. 5a). Furthermore, we found that blocking of the JAK-STAT pathway partially reduced the DNA sensing-mediated antiviral activity, as indicated by both viral DNA (Fig. 5b) and plaque assay data (Fig. 5c). These results suggest that the DNA-sensing pathway could mediate antiviral effects in the absence of canonical IFN-JAK-STAT signaling. Moreover, we examined whether the DNA-sensing pathway can mediate antiviral ISGs expression independently of IFN signaling. Real-time PCR data showed that when IFN-JAK-STAT pathway was blocked by Ruxolitinib, transfection with poly(dA:dT) still induced expressions of ISGs, including IFIT1-3, ISG15 and Mx1, though the expression levels were lower than that in MSCs without Ruxolitinib treatment (Fig. 5d). Together, these data imply that cytosolic DNA sensing mediated both IFN-dependent and -independent antiviral effects.

Bottom Line: Cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) was identified as the sensor of MHV-68 in MSCs for the first time.Moreover, the cytosolic DNA sensing pathway mediated a potent anti-herpesviral effect through the adaptor STING and downstream kinase TBK1.Furthermore, blockade of IFN signaling suggested that cytosolic DNA sensing triggered both IFN-dependent and -independent anti-herpesviral responses.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Immunology, Institute of Tuberculosis Control, Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China [2] Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China.

ABSTRACT
Mesenchymal stem cells (MSCs) are widely used in clinical settings to treat tissue injuries and autoimmune disorders due to their multipotentiality and immunomodulation. Long-term observations reveal several complications after MSCs infusion, especially herpesviral infection. However, the mechanism of host defense against herpesviruses in MSCs remains largely unknown. Here we showed that murine gammaherpesvirus-68 (MHV-68), which is genetically and biologically related to human gammaherpesviruses, efficiently infected MSCs both in vitro and in vivo. Cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS) was identified as the sensor of MHV-68 in MSCs for the first time. Moreover, the cytosolic DNA sensing pathway mediated a potent anti-herpesviral effect through the adaptor STING and downstream kinase TBK1. Furthermore, blockade of IFN signaling suggested that cytosolic DNA sensing triggered both IFN-dependent and -independent anti-herpesviral responses. Our findings demonstrate that cGAS-STING mediates innate immunity to gammaherpesvirus infection in MSCs, which may provide a clue to develop therapeutic strategy.

No MeSH data available.


Related in: MedlinePlus