Hypoxia and TLR9 activation drive CXCL4 production in systemic sclerosis plasmacytoid dendritic cells via mtROS and HIF-2α

Andrea Ottria, Maili Zimmermann, Laurent M Paardekooper, Tiago Carvalheiro, Nadia Vazirpanah, Sandra Silva-Cardoso, Alsya J Affandi, Eleni Chouri, Maarten V D Kroef, Ralph G Tieland, Cornelis P J Bekker, Catharina G K Wichers, Marzia Rossato, Enric Mocholi-Gimeno, Janneke Tekstra, Evelien Ton, Jaap M van Laar, Marta Cossu, Lorenzo Beretta, Samuel Garcia PerezAridaman Pandit, Femke Bonte-Mineur, Kris A Reedquist, Geert van den Bogaart, Timothy R D J Radstake, Wioleta Marut

Onderzoeksoutput: Bijdrage aan tijdschriftArtikelpeer review

5 Citaten (Scopus)


Objective: SSc is a complex disease characterized by vascular abnormalities and inflammation culminating in hypoxia and excessive fibrosis. Previously, we identified chemokine (C-X-C motif) ligand 4 (CXCL4) as a novel predictive biomarker in SSc. Although CXCL4 is well-studied, the mechanisms driving its production are unclear. The aim of this study was to elucidate the mechanisms leading to CXCL4 production. Methods: Plasmacytoid dendritic cells (pDCs) from 97 healthy controls and 70 SSc patients were cultured in the presence of hypoxia or atmospheric oxygen level and/or stimulated with several toll-like receptor (TLR) agonists. Further, pro-inflammatory cytokine production, CXCL4, hypoxia-inducible factor (HIF)-1α and HIF-2α gene and protein expression were assessed using ELISA, Luminex, qPCR, FACS and western blot assays. Results: CXCL4 release was potentiated only when pDCs were simultaneously exposed to hypoxia and TLR9 agonist (P < 0.0001). Here, we demonstrated that CXCL4 production is dependent on the overproduction of mitochondrial reactive oxygen species (mtROS) (P = 0.0079) leading to stabilization of HIF-2α (P = 0.029). In addition, we show that hypoxia is fundamental for CXCL4 production by umbilical cord CD34 derived pDCs. Conclusion: TLR-mediated activation of immune cells in the presence of hypoxia underpins the pathogenic production of CXCL4 in SSc. Blocking either mtROS or HIF-2α pathways may therapeutically attenuate the contribution of CXCL4 to SSc and other inflammatory diseases driven by CXCL4.
Originele taal-2Engels
Pagina's (van-tot)2682-2693
Aantal pagina's12
TijdschriftRheumatology (Oxford, England)
Nummer van het tijdschrift6
StatusGepubliceerd - 30 mei 2022


  • CXCL4
  • HIF-2α
  • TLRs
  • hypoxia
  • mtROS
  • plasmacytoid dendritic cells
  • systemic sclerosis


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