Blockade of p38 Mitogen-Activated Protein Kinase Inhibits Murine Sclerodermatous Chronic Graft-versus-Host Disease

Abstract

Bone marrow transplantation (BMT) of B10.D2 mice into sublethally irradiated BALB/c mice across minor histocompatibility loci is a well-established animal model for human sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) and systemic sclerosis (SSc). The p38 mitogen-activated protein kinase (MAPK) pathway is a key regulator of inflammation and cytokine production. Furthermore, the activation of p38 MAPK plays an important role in collagen production in SSc. We investigated the effects of p38 MAPK inhibitor, VX-702, on Scl-cGVHD mice. VX-702 was orally administered to Scl-cGVHD mice from day 7 to 35 after BMT. We compared skin fibrosis of Scl-cGVHD mice between the VX-702-treated group and control group. Allogeneic BMT increased the phosphorylation of p38 MAPK in the skin. The administration of VX-702 attenuated the skin fibrosis of Scl-cGVHD compared to the control mice. Immunohistochemical staining showed that VX-702 suppressed the infiltration of CD4 T cells, CD8 T cells, and CD11b cells into the dermis of Scl-cGVHD mice compared to the control mice. VX-702 attenuated the mRNA expression of extracellular matrix and fibrogenic cytokines, such as IL-6 and IL-13, in the skin of Scl-cGVHD mice. In addition, VX-702 directly inhibited collagen production from fibroblasts in vitro. VX-702 was shown to be a promising candidate for use in treating patients with Scl-cGVHD and SSc.

Contribution of Interleukin-6 to the Pathogenesis of Systemic Sclerosis

“…Systemic sclerosis (SSc) is a complex disease resulting from impaired biological cell function, affecting endothelial cells,fibroblasts,lymphocytes,monocytes,andbonemarrow cells (1)(2)(3)(4).Vasculopathyandtissuefibrosisoccurasaresult oftheseimpairmentsandareconsideredtobethemainclinicalfeaturesofpatientswithSSc.Thesepatientshavedysregulation of genetic and epigenetic function (5-7), innate immunity(8),andresponsetoinfections,resultinginaberrant immuneactivationandacceleratedtissuedamageleadingto tissuefibrosis,vasculopathy,andautoimmunity.Inthepast2 decades,manycytokines (9)(10)(11)(12)(13)(14)(15)(16)(17)(18),chemokines (19)(20)(21),growth factors (22)(23)(24)(25)(26),andtranscriptionfactors (27,28)havebeen studied for their potential involvement in the pathogenesis of SSc. For example, in vitro and in vivo experiments using sclerodermamurinemodelshaverevealedthattransforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), and connective tissue growth factor may play crucial roles in collagen production by tissue fibroblasts in SSc (22)(23)(24)(25)(26).Inadditiontothesegrowthfactors,cytokines-including interleukin-1 (IL-1), IL-2, IL-4, IL-6, IL-8, IL-13, IL-33, and IL-35 -were found to be potent regulators of tissue…”

“…For example, in vitro and in vivo experiments using sclerodermamurinemodelshaverevealedthattransforming growth factor-beta (TGF-β), platelet-derived growth factor (PDGF), and connective tissue growth factor may play crucial roles in collagen production by tissue fibroblasts in SSc (22)(23)(24)(25)(26).Inadditiontothesegrowthfactors,cytokines-including interleukin-1 (IL-1), IL-2, IL-4, IL-6, IL-8, IL-13, IL-33, and IL-35 -were found to be potent regulators of tissue…”

Novel insights into dendritic cells in the pathogenesis of systemic sclerosis

“…In addition, results from clinical trials in other autoimmune diseases, in‐vitro experiments and mouse models support the idea of inhibiting certain signalling pathways downstream from PRR and cytokine receptor activation of DCs and other immune cells, such as the Janus kinase–signal transducer and activator of transcription (JAK–STAT) pathway by tofacitinib (clinical trial, Phase I/II, NCT03274076 ClinicalTrials.gov) and mitogen‐activated protein kinase (MAPK) p38 inhibition .…”

Attenuation of murine sclerodermatous models by the selective S1P1 receptor modulator cenerimod

“…As we described previously in our study 53 , a 1 × 3 cm piece of depilated back skin was minced and then digested in 5 mL of RPMI-10% fetal bovine serum containing 2.5 mg/mL collagenase D (Roche, Basel, Switzerland), 1.5 mg/mL hyaluronidase (Sigma-Aldrich), and 0.03 mg/mL DNase I (Roche) at 37 °C for 90 min. Digested cells were then passed through a 70-μm cell Falcon cell strainer (BD Biosciences) to generate single-cell suspensions.…”

“…The Live/Dead Fixable Aqua Dead Cell Stain kit was from Molecular probes (Waltham, MA). As we described previously in our study 53 , splenic and skin single cell suspensions were stained for 20 min for 2 to 4 color immunofluorescence at 4 °C using mAbs at predetermined optimal concentrations. After finished surface staining, the cells were washed, fixed and permeabilized for 30 min at 4 °C using the Foxp3/Transcription Factor Staining Buffer Set (eBioscience).…”