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Mitochondria-targeted antioxidant MitoQ ameliorates experimental mouse colitis by suppressing NLRP3 inflammasome-mediated inflammatory cytokines.

Dashdorj A, Jyothi KR, Lim S, Jo A, Nguyen MN, Ha J, Yoon KS, Kim HJ, Park JH, Murphy MP, Kim SS - BMC Med (2013)

Bottom Line: The effect of MitoQ on inflammatory cytokines released in the human macrophage-like cell line THP-1 was also analyzed.In vitro studies demonstrated that MitoQ decreases IL-1 beta and IL-18 production in human THP-1 cells.Taken together, our results suggest that MitoQ may have potential as a novel therapeutic agent for the treatment of acute phases of inflammatory bowel disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea.

ABSTRACT

Background: MitoQ is a mitochondria-targeted derivative of the antioxidant ubiquinone, with antioxidant and anti-apoptotic functions. Reactive oxygen species are involved in many inflammatory diseases including inflammatory bowel disease. In this study, we assessed the therapeutic effects of MitoQ in a mouse model of experimental colitis and investigated the possible mechanisms underlying its effects on intestinal inflammation.

Methods: Reactive oxygen species levels and mitochondrial function were measured in blood mononuclear cells of patients with inflammatory bowel disease. The effects of MitoQ were evaluated in a dextran sulfate sodium-induced colitis mouse model. Clinical and pathological markers of disease severity and oxidative injury, and levels of inflammatory cytokines in mouse colonic tissue were measured. The effect of MitoQ on inflammatory cytokines released in the human macrophage-like cell line THP-1 was also analyzed.

Results: Cellular and mitochondrial reactive oxygen species levels in mononuclear cells were significantly higher in patients with inflammatory bowel disease (P <0.003, cellular reactive oxygen species; P <0.001, mitochondrial reactive oxygen species). MitoQ significantly ameliorated colitis in the dextran sulfate sodium-induced mouse model in vivo, reduced the increased oxidative stress response (malondialdehyde and 3-nitrotyrosine formation), and suppressed mitochondrial and histopathological injury by decreasing levels of inflammatory cytokines IL-1 beta and IL-18 (P <0.001 and P <0.01 respectively). By decreasing mitochondrial reactive oxygen species, MitoQ also suppressed activation of the NLRP3 inflammasome that was responsible for maturation of IL-1 beta and IL-18. In vitro studies demonstrated that MitoQ decreases IL-1 beta and IL-18 production in human THP-1 cells.

Conclusion: Taken together, our results suggest that MitoQ may have potential as a novel therapeutic agent for the treatment of acute phases of inflammatory bowel disease.

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Related in: MedlinePlus

MitoQ inhibits caspase-1 activation through suppression of TXNIP binding to NLRP3 during colitis. (A) Western blotting analysis reveals expression of the NLRP3 inflammasome components in mouse colon homogenates. (B) Dissociation of the TXNIP-TRX complex upon MitoQ treatment, as revealed by co-immunoprecipitation. (C) Co-immunoprecipitation and western blotting analysis identify the interaction of TXNIP with NLRP3. IP, immunoprecipitation; input of cell extract without immunoprecipitation ensures equal loading. (D) Effect of MitoQ on mtROS production in peritoneal macrophages. Results are expressed as mean ±SE. n= 5. *P <0.01.
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Figure 4: MitoQ inhibits caspase-1 activation through suppression of TXNIP binding to NLRP3 during colitis. (A) Western blotting analysis reveals expression of the NLRP3 inflammasome components in mouse colon homogenates. (B) Dissociation of the TXNIP-TRX complex upon MitoQ treatment, as revealed by co-immunoprecipitation. (C) Co-immunoprecipitation and western blotting analysis identify the interaction of TXNIP with NLRP3. IP, immunoprecipitation; input of cell extract without immunoprecipitation ensures equal loading. (D) Effect of MitoQ on mtROS production in peritoneal macrophages. Results are expressed as mean ±SE. n= 5. *P <0.01.

Mentions: To clarify the mechanism of MitoQ in attenuation of colitis, we investigated the function of the NLRP3 inflammasome. The NLRP3 inflammasome comprises adaptor proteins ACS and caspase-1. It isknown that TXNIP binds to the leucine-rich repeat domain of NLRP3 and activates the inflammasome during oxidative stress [20]. TXNIP binds to TRX and negatively regulates its redox function in resting cells [36]. Oxidized TRX during oxidative stress is dissociated from the TXNIP-TRX complex, and leads to the interaction of TXNIP with NLRP3. Therefore, we hypothesized that binding of TXNIP to NLRP3 activates the inflammasome, which causes autocleavage of caspase-1 and the release of mature cytokines IL-1 beta and IL-18 during colitis. Western blotting analysis revealed that expression of the inflammasome complex proteins such as NLRP3 and ASC are not changed during colitis, but procaspase-1 is increased in its expression and cleaved into caspase-1 in DSS- and DSS+dTPP-treated mice. However, procaspase-1 was not cleaved in control and MitoQ-treated mice (Figure 4A). Next, we performed co-IP to check the interaction between TXNIP and NLRP3, and revealed that TXNIP is dissociated from TRX in DSS- and DSS+dTPP-treated mice (Figure 4B). During colitis, the dissociated TXNIP was bound to NLRP3, and this interaction was blocked by MitoQ treatment (Figure 4C). To gain more insight into the mechanism of oxidative stress-induced colitis, we isolated mouse peritoneal macrophages and measured mitochondrial ROS levels. Macrophages of DSS+MitoQ-treated mice released lower levels of ROS compared with macrophages of DSS- and DSS+dTPP-treated mice (Figure 4D). Therefore, we concluded that activation of NLRP3 inflammasome during colitis is dependent on the interaction of TXNIP and NLRP3, and that this activation is mediated by mtROS.


Mitochondria-targeted antioxidant MitoQ ameliorates experimental mouse colitis by suppressing NLRP3 inflammasome-mediated inflammatory cytokines.

Dashdorj A, Jyothi KR, Lim S, Jo A, Nguyen MN, Ha J, Yoon KS, Kim HJ, Park JH, Murphy MP, Kim SS - BMC Med (2013)

MitoQ inhibits caspase-1 activation through suppression of TXNIP binding to NLRP3 during colitis. (A) Western blotting analysis reveals expression of the NLRP3 inflammasome components in mouse colon homogenates. (B) Dissociation of the TXNIP-TRX complex upon MitoQ treatment, as revealed by co-immunoprecipitation. (C) Co-immunoprecipitation and western blotting analysis identify the interaction of TXNIP with NLRP3. IP, immunoprecipitation; input of cell extract without immunoprecipitation ensures equal loading. (D) Effect of MitoQ on mtROS production in peritoneal macrophages. Results are expressed as mean ±SE. n= 5. *P <0.01.
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Related In: Results  -  Collection

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Figure 4: MitoQ inhibits caspase-1 activation through suppression of TXNIP binding to NLRP3 during colitis. (A) Western blotting analysis reveals expression of the NLRP3 inflammasome components in mouse colon homogenates. (B) Dissociation of the TXNIP-TRX complex upon MitoQ treatment, as revealed by co-immunoprecipitation. (C) Co-immunoprecipitation and western blotting analysis identify the interaction of TXNIP with NLRP3. IP, immunoprecipitation; input of cell extract without immunoprecipitation ensures equal loading. (D) Effect of MitoQ on mtROS production in peritoneal macrophages. Results are expressed as mean ±SE. n= 5. *P <0.01.
Mentions: To clarify the mechanism of MitoQ in attenuation of colitis, we investigated the function of the NLRP3 inflammasome. The NLRP3 inflammasome comprises adaptor proteins ACS and caspase-1. It isknown that TXNIP binds to the leucine-rich repeat domain of NLRP3 and activates the inflammasome during oxidative stress [20]. TXNIP binds to TRX and negatively regulates its redox function in resting cells [36]. Oxidized TRX during oxidative stress is dissociated from the TXNIP-TRX complex, and leads to the interaction of TXNIP with NLRP3. Therefore, we hypothesized that binding of TXNIP to NLRP3 activates the inflammasome, which causes autocleavage of caspase-1 and the release of mature cytokines IL-1 beta and IL-18 during colitis. Western blotting analysis revealed that expression of the inflammasome complex proteins such as NLRP3 and ASC are not changed during colitis, but procaspase-1 is increased in its expression and cleaved into caspase-1 in DSS- and DSS+dTPP-treated mice. However, procaspase-1 was not cleaved in control and MitoQ-treated mice (Figure 4A). Next, we performed co-IP to check the interaction between TXNIP and NLRP3, and revealed that TXNIP is dissociated from TRX in DSS- and DSS+dTPP-treated mice (Figure 4B). During colitis, the dissociated TXNIP was bound to NLRP3, and this interaction was blocked by MitoQ treatment (Figure 4C). To gain more insight into the mechanism of oxidative stress-induced colitis, we isolated mouse peritoneal macrophages and measured mitochondrial ROS levels. Macrophages of DSS+MitoQ-treated mice released lower levels of ROS compared with macrophages of DSS- and DSS+dTPP-treated mice (Figure 4D). Therefore, we concluded that activation of NLRP3 inflammasome during colitis is dependent on the interaction of TXNIP and NLRP3, and that this activation is mediated by mtROS.

Bottom Line: The effect of MitoQ on inflammatory cytokines released in the human macrophage-like cell line THP-1 was also analyzed.In vitro studies demonstrated that MitoQ decreases IL-1 beta and IL-18 production in human THP-1 cells.Taken together, our results suggest that MitoQ may have potential as a novel therapeutic agent for the treatment of acute phases of inflammatory bowel disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea.

ABSTRACT

Background: MitoQ is a mitochondria-targeted derivative of the antioxidant ubiquinone, with antioxidant and anti-apoptotic functions. Reactive oxygen species are involved in many inflammatory diseases including inflammatory bowel disease. In this study, we assessed the therapeutic effects of MitoQ in a mouse model of experimental colitis and investigated the possible mechanisms underlying its effects on intestinal inflammation.

Methods: Reactive oxygen species levels and mitochondrial function were measured in blood mononuclear cells of patients with inflammatory bowel disease. The effects of MitoQ were evaluated in a dextran sulfate sodium-induced colitis mouse model. Clinical and pathological markers of disease severity and oxidative injury, and levels of inflammatory cytokines in mouse colonic tissue were measured. The effect of MitoQ on inflammatory cytokines released in the human macrophage-like cell line THP-1 was also analyzed.

Results: Cellular and mitochondrial reactive oxygen species levels in mononuclear cells were significantly higher in patients with inflammatory bowel disease (P <0.003, cellular reactive oxygen species; P <0.001, mitochondrial reactive oxygen species). MitoQ significantly ameliorated colitis in the dextran sulfate sodium-induced mouse model in vivo, reduced the increased oxidative stress response (malondialdehyde and 3-nitrotyrosine formation), and suppressed mitochondrial and histopathological injury by decreasing levels of inflammatory cytokines IL-1 beta and IL-18 (P <0.001 and P <0.01 respectively). By decreasing mitochondrial reactive oxygen species, MitoQ also suppressed activation of the NLRP3 inflammasome that was responsible for maturation of IL-1 beta and IL-18. In vitro studies demonstrated that MitoQ decreases IL-1 beta and IL-18 production in human THP-1 cells.

Conclusion: Taken together, our results suggest that MitoQ may have potential as a novel therapeutic agent for the treatment of acute phases of inflammatory bowel disease.

Show MeSH
Related in: MedlinePlus