Genetic variants in LGALS3 are related to lower galectin-3 serum levels and clinical outcomes in systemic sclerosis patients: A case-control study.

INTRODUCTION: Systemic sclerosis (SSc) is a rare complex disease characterized by vascular damage, autoimmunity, and extensive skin and internal organs fibrosis. Galectin-3 (Gal-3) is encoded by gene LGALS3 (Lectin, Galactoside-Binding, Soluble, 3; 14q22.3) and it has been reported to play a central role in self-tolerance, inflammation, and fibrosis. OBJECTIVE: To investigate associations among LGALS3 single nucleotide polymorphisms (SNPs) and serum levels Gal-3 and SSc susceptibility and their clinical features. METHODS: A case-control study with 88 patients and 151 matched controls was performed. LGALS3 variants were analyzed by the TaqMan real-time polymerase chain reaction (PCR) system whereas Gal-3 serum levels were measured by sandwich enzyme linked immunosorbent assay (ELISA). Associations among genotypes, clinical features, and Gal-3 levels were performed by univariable and multivariable analysis through statistical packages. RESULTS: The LGALS3 rs4652 A/C genotype was more frequent in SSc patients than controls according to overdominant model [OR 1.89 (CI 95% 1.01 - 3.52); p = .046]. Also, LGALS3 rs4652 C/C polymorphic genotype was associated with lower patient Gal-3 levels (p = .03) and control group (p = 0.005), as noted by generalized linear model (GLM). The LGALS3 rs1009977 G/T controls showed higher Gal-3 levels than wild-type and polymorphic genotypes (p = .03); however, in SSc patients, no difference was found. None of the LGALS3 SNPs or Gal-3 levels was associated with clinical manifestations in SSc patients. Considering only the SSc group, GLM analysis pointed LGALS3 rs4652 and rs2075601, pulmonary arterial hypertension (PAH), myopathy, and health assessment questionnaire (HAQ) and scleroderma health assessment questionnaire (SHAQ) as important predictors for Gal-3 levels. CONCLUSION: The LGALS3 rs4652 A/C was more frequent in SSc patients and related to lower Gal-3 levels. These findings were corroborated through a GLM to estimate Gal-3 values. Also, by model equations, Gal-3 levels may be predicted by HAQ, SHAQ, PAH, myopathy, and LGALS3 rs4652 and rs2075601 factors. In these ways, we suggest that galectins may be promising biomarkers to identify susceptibility to SSc as well as to identify HAQ, SHAQ, PAH, and myopathy outcomes.

CCL3, IL-7, IL-13 and IFNγ transcripts are increased in skin's biopsy of systemic sclerosis.

Although several cytokines and chemokines have been investigated as possible mediators of fibrosis in systemic sclerosis (SSc), specific correlation between cytokines and organ involvement have not been found yet, and a cytokine profile characteristic of SSc is far to be identified. We studied the profile of antifibrotic and profibrotic transcripts involved in skin of SSc patients. The mRNA expression was detected by fluorescence-based quantitative real-time PCR (qPCR) in skin's biopsies from 14 patients with SSc and 5 healthy controls. PDGF-A, CTGF, CCL3, IL-6, IL-13, IL-7, IFNγ, IL-17, IL-22 and RORc were analysed in these samples. CCL3, IL-7, IL-13 and IFN-γ were more expressed in skin's biopsy of patients with SSc (P = 0.0002, P = 0.0082, P = 0.0243, P = 0.0335, respectively) when compared with healthy controls. We also found a positive correlation between CCL3 and IL-7 transcripts (P = 0.0050 r = 0.7187). Furthermore, we observed that patients with lung involvement had lower expression of PDGF-A (P = 0.0385). We found an increase in IL-7, IFN-γ, CCL3 and IL-13 relative mRNA expressions on the skin's biopsy of patients with SSc, and a positive correlation between IL-7 and CCL3. These molecules are involved in the pathogenesis of SSc, and how their interactions occur should be the subject of further studies.

Different profile of cytokine production in patients with systemic sclerosis and association with clinical manifestations.

Immune dysregulation is a central process in the pathogenesis of systemic sclerosis (SSc). Cytokines produced by lymphocytes and monocytes are important mediators and induce tissue damage, recruit additional inflammatory cells, and promote extracellular matrix production and fibrosis. In the present research, we aimed to study the associations between levels of cytokines in serum and culture supernatants from peripheral blood mononuclear cells (PBMCs) and clinical manifestations in SSc patients. Serum samples were obtained from 56 SSc patients and 56 unrelated age- and gender-matched healthy individuals. Resting and anti-CD3/CD28-stimulated PBMC cultures were obtained from 19 SSc patients and 8 healthy controls. IL-2, IL-4, IL-6, IL-10, IL-17A, TNF, and IFN-γ levels were measured by ELISA or CBA. Serum cytokines, except IL-17A, were below the kit detection limit in most of the patients and controls. In unstimulated PBMC, the production of TNF(p = 0.004), IL-10(p = .048), IL-2(p < 0.001), and IL-6 (p = 0.01) was higher in SSc patients than in healthy controls. After anti-CD3/CD28 stimulation, scleroderma PBMCs had lower concentrations of TNF(p = 0.009), IL-10(p = .018), and IL-2(p = .002) than HC. In unstimulated PBMC, IL-2 concentration was higher in patients with esophageal dysmotility (p = 0.04), and IL-10 levels had a positive correlation with modified Rodnan score (p = 0.03). After anti-CD3/CD28 stimulation, higher levels of IL-2 and IL-4 were observed in SSc patients with lung fibrosis (p = 0.01 and 0.006, respectively), and higher levels of IL-10 (p = 0.04) and IL-4 (p = 0.04) in patients with digital ulcers. In conclusion, SSc patients have a different profile of cytokine production and this was associated with clinical manifestations.

IL-17 and related cytokines involved in systemic sclerosis: Perspectives.

Systemic sclerosis (SSc) is a multisystemic, complex, and rare disease of connective tissue, with high morbidity and mortality, and without specific treatment. The disease is characterized by three main principles: vascular disease, autoantibody production and inflammation, and fibrosis. Since it is well defined that SSc is characterized by elevated production of TGF-ß, IL-6, and IL-1, all of them cytokines related to Th17 differentiation, the hypothesis is that this disease may be strongly related to a polarization of the immune response towards the Th17 pathway. Considering the importance of a better understanding of the pathophysiology of Th17 pathway in SSc, this article aims to propose an update for a better understanding of current knowledge on main cytokines secreted by the Th17 cells (IL-17 A, IL-21, and IL-22) and the future prospects in the current disease.