OBJECTIVE: Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is characterized by variable clinical outcomes, activation of innate immune pattern-recognition receptors (PRRs), and accumulation of α-smooth muscle actin (α-SMA)-expressing myofibroblasts. The aim of this study was to identify an association between these entities and mitochondrial DNA (mtDNA), an endogenous ligand for the intracellular DNA-sensing PRRs Toll-like receptor 9 (TLR-9) and cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING), which has yet to be determined. METHODS: Human lung fibroblasts (HLFs) from normal donors and SSc-ILD explants were treated with synthetic CpG DNA and assayed for α-SMA expression and extracellular mtDNA using quantitative polymerase chain reaction for the human MT-ATP6 gene. Plasma MT-ATP6 concentrations were evaluated in 2 independent SSc-ILD cohorts and demographically matched controls. The ability of SSc-ILD and control plasma to induce TLR-9 and cGAS/STING activation was evaluated with commercially available HEK 293 reporter cells. Plasma concentrations of type I interferons (IFNs), interleukin-6 (IL-6), and oxidized DNA were measured using electrochemiluminescence and enzyme-linked immunosorbent assay-based methods. Extracellular vesicles (EVs) precipitated from plasma were evaluated for MT-ATP6 concentrations and proteomics via liquid chromatography mass spectrometry. RESULTS: Normal HLFs and SSc-ILD fibroblasts developed increased α-SMA expression and MT-ATP6 release following CpG stimulation. Plasma mtDNA concentrations were increased in the 2 SSc-ILD cohorts, reflective of ventilatory decline, and were positively associated with both TLR-9 and cGAS/STING activation as well as type I IFN and IL-6 expression. Plasma mtDNA was not oxidized and was conveyed by EVs displaying a proteomics profile consistent with a multicellular origin. CONCLUSION: These findings demonstrate a previously unrecognized connection between EV-encapsulated mtDNA, clinical outcomes, and intracellular DNA-sensing PRR activation in SSc-ILD. Further study of these interactions could catalyze novel mechanistic and therapeutic insights into SSc-ILD and related disorders.
OBJECTIVE: Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is characterized by variable clinical outcomes, activation of innate immune pattern-recognition receptors (PRRs), and accumulation of α-smooth muscle actin (α-SMA)-expressing myofibroblasts. The aim of this study was to identify an association between these entities and mitochondrial DNA (mtDNA), an endogenous ligand for the intracellular DNA-sensing PRRs Toll-like receptor 9 (TLR-9) and cyclic GMP-AMP synthase/stimulator of interferon genes (cGAS/STING), which has yet to be determined. METHODS: Human lung fibroblasts (HLFs) from normal donors and SSc-ILD explants were treated with synthetic CpG DNA and assayed for α-SMA expression and extracellular mtDNA using quantitative polymerase chain reaction for the human MT-ATP6 gene. Plasma MT-ATP6 concentrations were evaluated in 2 independent SSc-ILD cohorts and demographically matched controls. The ability of SSc-ILD and control plasma to induce TLR-9 and cGAS/STING activation was evaluated with commercially available HEK 293 reporter cells. Plasma concentrations of type I interferons (IFNs), interleukin-6 (IL-6), and oxidized DNA were measured using electrochemiluminescence and enzyme-linked immunosorbent assay-based methods. Extracellular vesicles (EVs) precipitated from plasma were evaluated for MT-ATP6 concentrations and proteomics via liquid chromatography mass spectrometry. RESULTS: Normal HLFs and SSc-ILD fibroblasts developed increased α-SMA expression and MT-ATP6 release following CpG stimulation. Plasma mtDNA concentrations were increased in the 2 SSc-ILD cohorts, reflective of ventilatory decline, and were positively associated with both TLR-9 and cGAS/STING activation as well as type I IFN and IL-6 expression. Plasma mtDNA was not oxidized and was conveyed by EVs displaying a proteomics profile consistent with a multicellular origin. CONCLUSION: These findings demonstrate a previously unrecognized connection between EV-encapsulated mtDNA, clinical outcomes, and intracellular DNA-sensing PRR activation in SSc-ILD. Further study of these interactions could catalyze novel mechanistic and therapeutic insights into SSc-ILD and related disorders.
Authors: Nicole S Goh; Rachel K Hoyles; Christopher P Denton; David M Hansell; Elisabetta A Renzoni; Toby M Maher; Andrew G Nicholson; Athol U Wells Journal: Arthritis Rheumatol Date: 2017-07-18 Impact factor: 10.995
Authors: Changwan Ryu; Huanxing Sun; Mridu Gulati; Jose D Herazo-Maya; Yonglin Chen; Awo Osafo-Addo; Caitlin Brandsdorfer; Julia Winkler; Christina Blaul; Jaden Faunce; Hongyi Pan; Tony Woolard; Argyrios Tzouvelekis; Danielle E Antin-Ozerkis; Jonathan T Puchalski; Martin Slade; Anjelica L Gonzalez; Daniel F Bogenhagen; Varvara Kirillov; Carol Feghali-Bostwick; Kevin Gibson; Kathleen Lindell; Raimund I Herzog; Charles S Dela Cruz; Wajahat Mehal; Naftali Kaminski; Erica L Herzog; Glenda Trujillo Journal: Am J Respir Crit Care Med Date: 2017-12-15 Impact factor: 21.405
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Authors: Romy B Christmann; Alicia Wooten; Percival Sampaio-Barros; Claudia L Borges; Carlos R R Carvalho; Ronaldo A Kairalla; Carol Feghali-Bostwick; Jessica Ziemek; Yu Mei; Salma Goummih; Jiangning Tan; Diana Alvarez; Daniel J Kass; Mauricio Rojas; Thiago Lemos de Mattos; Edwin Parra; Giuseppina Stifano; Vera L Capelozzi; Robert W Simms; Robert Lafyatis Journal: Arthritis Res Ther Date: 2016-07-05 Impact factor: 5.156
Authors: Liu Cui; Jing Weiyao; Su Chenghong; Liu Limei; Zhang Xinghua; Yuan Bo; Du Xiaozheng; Wang Haidong Journal: Front Med (Lausanne) Date: 2022-09-23