Dataset Information

Molecular Basis for Dysregulated Activation of NKX2-5 in the Vascular Remodeling of Systemic Sclerosis.

ABSTRACT: OBJECTIVE:NKX2-5 is a homeobox transcription factor that is required for the formation of the heart and vessels during development, with significant postnatal down-regulation and reactivation in disease states, characterized by vascular remodeling. The purpose of this study was to investigate mechanisms that activate NKX2-5 expression in diseased vessels, such as systemic sclerosis (scleroderma; SSc)-associated pulmonary hypertension (PH), and to identify genetic variability that potentially underlies susceptibility to specific vascular complications. METHODS:We explored NKX2-5 expression in biopsy samples from patients with SSc-associated PH and in pulmonary artery smooth muscle cells (PASMCs) from patients with scleroderma. Disease-associated putative functional single-nucleotide polymorphisms (SNPs) at the NKX2-5 locus were cloned and studied in reporter gene assays. SNP function was further examined through protein-DNA binding assays, chromatin immunoprecipitation assays, and RNA silencing analyses. RESULTS:Increased NKX2-5 expression in biopsy samples from patients with SSc-associated PH was localized to remodeled vessels and PASMCs. Meta-analysis of 2 independent scleroderma cohorts revealed an association of rs3131917 with scleroderma (P = 0.029). We demonstrated that disease-associated SNPs are located in a novel functional enhancer, which increases NKX2-5 transcriptional activity through the binding of GATA-6, c-Jun, and myocyte-specific enhancer factor 2C. We also characterized an activator/coactivator transcription-enhancer factor domain 1 (TEAD1)/Yes-associated protein 1 (YAP1) complex, which was bound at rs3095870, another functional SNP, with TEAD1 binding the risk allele and activating the transcription of NKX2-5. CONCLUSION:NKX2-5 is genetically associated with scleroderma, pulmonary hypertension, and fibrosis. Functional evidence revealed a regulatory mechanism that results in NKX2-5 transcriptional activation in PASMCs through the interaction of an upstream promoter and a novel downstream enhancer. This mechanism can act as a model for NKX2-5 activation in cardiovascular disease characterized by vascular remodeling.

SUBMITTER: Dritsoula A

PROVIDER: S-EPMC6001790 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Molecular Basis for Dysregulated Activation of NKX2-5 in the Vascular Remodeling of Systemic Sclerosis.

Dritsoula Athina A Papaioannou Ioannis I Guerra Sandra G SG Fonseca Carmen C Martin Javier J Herrick Ariane L AL Abraham David J DJ Denton Christopher P CP Ponticos Markella M Ponticos Markella M

Arthritis & rheumatology (Hoboken, N.J.) 20180424 6

<h4>Objective</h4>NKX2-5 is a homeobox transcription factor that is required for the formation of the heart and vessels during development, with significant postnatal down-regulation and reactivation in disease states, characterized by vascular remodeling. The purpose of this study was to investigate mechanisms that activate NKX2-5 expression in diseased vessels, such as systemic sclerosis (scleroderma; SSc)-associated pulmonary hypertension (PH), and to identify genetic variability that potenti ...[more]

PMID: 29342503

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Project description:ObjectiveVascular remodeling diseases (VRD) are mainly characterized by inflammation and a vascular smooth muscle cells (VSMCs) proproliferative and anti-apoptotic phenotype. Recently, the activation of the advanced glycation endproducts receptor (RAGE) has been shown to promote VSMC proliferation and resistance to apoptosis in VRD in a signal transducer and activator of transcription (STAT)3-dependant manner. Interestingly, we previously described in both cancer and VRD that the sustainability of this proproliferative and antiapoptotic phenotype requires activation of the transcription factor NFAT (nuclear factor of activated T-cells). In cancer, NFAT activation is dependent of the oncoprotein provirus integration site for Moloney murine leukemia virus (Pim1), which is regulated by STAT3 and activated in VRD. Therefore, we hypothesized that RAGE/STAT3 activation in VSMC activates Pim1, promoting NFAT and thus VSMC proliferation and resistance to apoptosis. Methods/Results- In vitro, freshly isolated human carotid VSMCs exposed to RAGE activator Nε-(carboxymethyl)lysine (CML) for 48 hours had (1) activated STAT3 (increased P-STAT3/STAT3 ratio and P-STAT3 nuclear translocation); (2) increased STAT3-dependent Pim1 expression resulting in NFATc1 activation; and (3) increased Pim1/NFAT-dependent VSMC proliferation (PCNA, Ki67) and resistance to mitochondrial-dependent apoptosis (TMRM, Annexin V, TUNEL). Similarly to RAGE inhibition (small interfering RNA [siRNA]), Pim1, STAT3 and NFATc1 inhibition (siRNA) reversed these abnormalities in human carotid VSMC. Moreover, carotid artery VSMCs isolated from Pim1 knockout mice were resistant to CML-induced VSMC proliferation and resistance to apoptosis. In vivo, RAGE inhibition decreases STAT3/Pim1/NFAT activation, reversing vascular remodeling in the rat carotid artery-injured model.ConclusionsRAGE activation accounts for many features of VRD including VSMC proliferation and resistance to apoptosis by the activation of STAT3/Pim1/NFAT axis. Molecules aimed to inhibit RAGE could be of a great therapeutic interest for the treatment of VRD.

Project description:IntroductionPreviously, we discovered similar esophageal gene expression patterns in patients with systemic sclerosis (SSc) and eosinophilic esophagitis (EoE) where eosinophil/mast cell-targeted therapies are beneficial. Because SSc and EoE patients experience similar esophageal symptoms, we hypothesized that eosinophil/mast cell-directed therapy may potentially benefit SSc patients. Herein, we determine the association between esophageal mast cell quantities, gene expression and clinical parameters in order to identify SSc patients who may benefit from eosinophil/mast cell-directed therapy.MethodsEsophageal biopsies from SSc patients and healthy participants were stained for tryptase, a mast cell marker, and associations with relevant clinical parameters including 24h esophageal pH testing were assessed. Intra-epithelial mast cell density was quantified by semi-automated microscopy. Microarray data were utilized for functional and gene set enrichment analyses and to identify intrinsic subset (IS) assignment, an SSc molecular classification system that includes inflammatory, proliferative, limited and normal-like subsets.ResultsEsophageal biopsies from 40 SSc patients (39 receiving proton pump inhibition) and eleven healthy participants were studied. Mast cell numbers in both the upper esophagus (rs = 0.638, p = 0.004) and the entire (upper + lower) esophagus (rs = 0.562, p = 0.019) significantly correlated with acid exposure time percentage. The inflammatory, fibroproliferative, and normal-like ISs originally defined in skin biopsies were identified in esophageal biopsies. Although esophageal mast cell numbers in SSc patients and healthy participants were similar, gene expression for mast cell-related pathways showed significant upregulation in the inflammatory IS of SSc patients compared to patients classified as proliferative or normal-like.DiscussionEsophageal mast cell numbers are heterogeneous in SSc patients and may correlate with acid exposure. Patients with inflammatory IS profiles in the esophagus demonstrate more tryptase staining. Mast cell targeted therapy may be a useful therapeutic approach in SSc patients belonging to the inflammatory IS, but additional studies are warranted.

Dataset Information

Molecular Basis for Dysregulated Activation of NKX2-5 in the Vascular Remodeling of Systemic Sclerosis.

Publications

Molecular Basis for Dysregulated Activation of NKX2-5 in the Vascular Remodeling of Systemic Sclerosis.

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