Combined anti-fibrotic and anti-inflammatory properties of JAK-inhibitors on macrophages in vitro and in vivo: Perspectives for scleroderma-associated interstitial lung disease

Biochem Pharmacol. 2020 Aug:178:114103. doi: 10.1016/j.bcp.2020.114103. Epub 2020 Jun 17.


Janus kinase (JAK) inhibitors (also termed Jakinibs) constitute a family of small drugs that target various isoforms of JAKs (JAK1, JAK2, JAK3 and/or tyrosine kinase 2 (Tyk2)). They exert anti-inflammatory properties linked, in part, to the modulation of the activation state of pro-inflammatory M1 macrophages. The exact impact of JAK inhibitors on a wider spectrum of activation states of macrophages is however still to be determined, especially in the context of disorders involving concomitant activation of pro-inflammatory M1 macrophages and profibrotic M2 macrophages. This is especially the case in autoimmune pulmonary fibrosis like scleroderma-associated interstitial lung disease (ILD), in which M1 and M2 macrophages play a key pathogenic role. In this study, we directly compared the anti-inflammatory and anti-fibrotic effects of three JAK inhibitors (ruxolitinib (JAK2/1 inhibitor); tofacitinib (JAK3/2 inhibitor) and itacitinib (JAK1 inhibitor)) on five different activation states of primary human monocyte-derived macrophages (MDM). These three JAK inhibitors exert anti-inflammatory properties towards macrophages, as demonstrated by the down-expression of key polarization markers (CD86, MHCII, TLR4) and the limited secretion of key pro-inflammatory cytokines (CXCL10, IL-6 and TNFα) in M1 macrophages activated by IFNγ and LPS or by IFNγ alone. We also highlighted that these JAK inhibitors can limit M2a activation of macrophages induced by IL-4 and IL-13, as notably demonstrated by the down-regulation of the M2a associated surface marker CD206 and of the secretion of CCL18. Moreover, these JAK inhibitors reduced the expression of markers such as CXCL13, MARCO and SOCS3 in alternatively activated macrophages induced by IL-10 and dexamethasone (M2c + dex) or IL-10 alone (M2c MDM). For all polarization states, Jakinibs with inhibitory properties over JAK2 had the highest effects, at both 1 μM or 0.1 μM. Based on these in vitro results, we also explored the effects of JAK2/1 inhibition by ruxolitinib in vivo, on mouse macrophages in a model of HOCl-induced ILD, that mimics scleroderma-associated ILD. In this model, we showed that ruxolitinib significantly prevented the upregulation of pro-inflammatory M1 markers (TNFα, CXCL10, NOS2) and pro-fibrotic M2 markers (Arg1 and Chi3L3). These results were associated with an improvement of skin and pulmonary involvement. Overall, our results suggest that the combined anti-inflammatory and anti-fibrotic properties of JAK2/1 inhibitors could be relevant to target lung macrophages in autoimmune and inflammatory pulmonary disorders that have no efficient disease modifying drugs to date.

Keywords: Inflammation; Interstitial Lung disease; Janus kinase inhibitors; Macrophage activation; Systemic sclerosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Differentiation
  • Chemokine CXCL13 / genetics
  • Chemokine CXCL13 / immunology
  • Female
  • Gene Expression Regulation
  • Hypochlorous Acid / administration & dosage
  • Janus Kinase 1 / antagonists & inhibitors
  • Janus Kinase 1 / genetics
  • Janus Kinase 1 / immunology
  • Janus Kinase 2 / antagonists & inhibitors
  • Janus Kinase 2 / genetics
  • Janus Kinase 2 / immunology
  • Janus Kinase 3 / antagonists & inhibitors
  • Janus Kinase 3 / genetics
  • Janus Kinase 3 / immunology
  • Lung / drug effects
  • Lung / immunology
  • Lung / pathology
  • Lung Diseases, Interstitial / chemically induced
  • Lung Diseases, Interstitial / drug therapy*
  • Lung Diseases, Interstitial / immunology
  • Lung Diseases, Interstitial / pathology
  • Macrophage Activation / drug effects
  • Macrophages / drug effects*
  • Macrophages / immunology
  • Macrophages / pathology
  • Mice
  • Mice, Inbred C57BL
  • Nitriles
  • Piperidines / pharmacology*
  • Primary Cell Culture
  • Protein Kinase Inhibitors / pharmacology*
  • Pyrazoles / pharmacology*
  • Pyrimidines / pharmacology*
  • Pyrroles / pharmacology*
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / immunology
  • Scleroderma, Systemic / chemically induced
  • Scleroderma, Systemic / drug therapy*
  • Scleroderma, Systemic / immunology
  • Scleroderma, Systemic / pathology
  • Suppressor of Cytokine Signaling 3 Protein / genetics
  • Suppressor of Cytokine Signaling 3 Protein / immunology


  • Anti-Inflammatory Agents
  • Chemokine CXCL13
  • Cxcl13 protein, mouse
  • Marco protein, mouse
  • Nitriles
  • Piperidines
  • Protein Kinase Inhibitors
  • Pyrazoles
  • Pyrimidines
  • Pyrroles
  • Receptors, Immunologic
  • Socs3 protein, mouse
  • Suppressor of Cytokine Signaling 3 Protein
  • Hypochlorous Acid
  • ruxolitinib
  • tofacitinib
  • Jak1 protein, mouse
  • Jak2 protein, mouse
  • Jak3 protein, mouse
  • Janus Kinase 1
  • Janus Kinase 2
  • Janus Kinase 3