Osteopontin: another piece in the systemic lupus erythematosus immunopathology puzzle.

Osteopontin (OPN) is a phosphoglycoprotein involved in bone remodelling, wound healing, cell adhesion, tissue remodelling, and immune response that is distributed widely in normal adult tissues. OPN biological activity is regulated by thrombin and matrix metalloproteinases (MMPs) cleavage, where the full-length (OPN-FL) protein and the cleaved OPN-N are associated with autoimmune diseases such as systemic lupus erythematosus (SLE). OPN overexpression has been associated with a predisposition to SLE and bad prognosis since OPN could mediate a sustained polyclonal B cell activation that besides to intracellular OPN (iOPN) form, promote the T follicular helper (TFH) cells and enhance anti-nuclear antibody production. Currently, the role of OPN in lupus nephritis (LN) has been reported and extensively studied; however, no data are available about the potential mechanism of OPN in neuropsychiatric SLE (NPSLE). In this review, we highlighted the contribution of OPN and iOPN in LN and NPSLE immunopathology.

The DNA co-vaccination using Sm antigen and IL-10 as prophylactic experimental therapy ameliorates nephritis in a model of lupus induced by pristane.

INTRODUCTION: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies such as anti-Sm. Studies in patients with SLE and murine models of lupus reveal that the most critical anti-Sm autoantibodies are predominantly direct against D1(83-119), D2, and B´/B epitopes. OBJECTIVES: The present study aimed to analyze the induction of antigen-specific tolerance after prophylactic immunization with a DNA vaccine encoding the epitopes: D183-119, D2, B´/B, and B´/BCOOH in co-vaccination with IFN-γ or IL-10 in a murine model of lupus induced by pristane. MATERIAL AND METHODS: To obtain endotoxin-free DNA vaccines, direct cloning techniques using pcDNA were performed: D183-119, D2, B´/B, B´/BCOOH, IFN-γ, or IL-10. Lupus was induced by 0.5 mL of pristane via intraperitoneal in BALB/c female mice. Immunoprecipitation with K562 cells was metabolically labeled with 35S and ELISA to detect serum antibodies or mice IgG1, IgG2a isotypes. ELISA determined IL-10 and IFN-γ from splenocytes supernatants. Proteinuria was assessed monthly, and lupus nephritis was evaluated by immunofluorescence, and electron microscopy. RESULTS: The prophylactic co-vaccination with D2/IL-10 reduced the expression of kidney damage observed by electron microscopy, direct immunofluorescence, and H & E, along with reduced level of anti-nRNP/Sm antibodies (P = 0.048). CONCLUSION: The prophylactic co-vaccination of IL-10 with D2 in pristane-induced lupus ameliorates the renal damage maybe by acting as prophylactic DNA tolerizing therapy.

miR-10b promotes aortic aneurysm formation and aortic rupture in angiotensin II-induced ApoE-deficient mice.

Abdominal aortic aneurysm (AAA) is associated with increased plasma levels of microRNA (miR) -10b. 5 nmols of miR-10b or miR control was administrated to Apolipoprotein E-deficient mice three days prior implantation of osmotic mini-pumps containing angiotensin II, and for three additional times once a week, which increased expression of miR-10b in plasma. Animals receiving miR-10b had a mortality rate due to aortic rupture of 61% compared to 11% in the miR controls (p < 0.05). Further, miR- 10b resulted in an increased aneurysm formation and growth (p < 0.05), which was accompanied by increased elastin degradation, neutrophil and mast cell markers (p < 0.05). In conclusion, miR-10b is functionally affecting aneurysm development and rupture and not only a marker of AAA. More mechanistic studies are required to better understand miR-10b's role in AAA formation.

Inverse Relationship of the CMKLR1 Relative Expression and Chemerin Serum Levels in Obesity with Dysmetabolic Phenotype and Insulin Resistance.

BACKGROUND: In obesity there is a subclinical chronic low-grade inflammatory response where insulin resistance (IR) may develop. Chemerin is secreted in white adipose tissue and promotes low-grade inflammatory process, where it expressed CMKLR1 receptor. The role of chemerin and CMKLR1 in inflammatory process secondary to obesity is not defined yet. METHODS: Cross-sectional study with 134 individuals classified as with and without obesity by body mass index (BMI) and IR. Body fat storage measurements and metabolic and inflammatory markers were measured by routine methods. Soluble chemerin and basal levels of insulin by ELISA and relative expression of CMKLR1 were evaluated with qPCR and 2(-ΔΔCT) method. RESULTS: Differences (P < 0.05) were observed between obesity and lean individuals in body fat storage measurements and metabolic-inflammatory markers. Both CMKLR1 expression and chemerin levels were increased in obesity without IR. Soluble chemerin levels correlate with adiposity and metabolic markers (r = 8.8% to 38.5%), P < 0.05. CONCLUSION: The increment of CMKLR1 expression was associated with insulin production. Increased serum levels of chemerin in obesity were observed, favoring a dysmetabolic response. The results observed in this study suggest that both chemerin and CMKLR1 have opposite expression in the context of low-grade inflammatory response manifested in the development of IR.

CCL2 Serum Levels and Adiposity Are Associated with the Polymorphic Phenotypes -2518A on CCL2 and 64ILE on CCR2 in a Mexican Population with Insulin Resistance.

Genetic susceptibility has been described in insulin resistance (IR). Chemokine (C-C motif) ligand-2 (CCL2) is overexpressed in white adipose tissue and is the ligand of C-C motif receptor-2 (CCR2). The CCL2 G-2518A polymorphism is known to regulate gene expression, whereas the physiological effects of the CCR2Val64Ile polymorphism are unknown. The aim of the study is to investigate the relationship between these polymorphisms with soluble CCL2 levels (sCCL2), metabolic markers, and adiposity. In a cross-sectional study we included 380 Mexican-Mestizo individuals, classified with IR according to Stern criteria. Polymorphism was identified using PCR-RFLP/sequence-specific primers. Anthropometrics and metabolic markers were measured by routine methods and adipokines and sCCL2 by ELISA. The CCL2 polymorphism was associated with IR (polymorphic A+ phenotype frequencies were 70.9%, 82.6%, in individuals with and without IR, resp.). Phenotype carriers CCL2 (A+) displayed lower body mass and fat indexes, insulin and HOMA-IR, and higher adiponectin levels. Individuals with IR presented higher sCCL2 compared to individuals without IR and was associated with CCR2 (Ile+) phenotype. The double-polymorphic phenotype carriers (A+/Ile+) exhibited higher sCCL2 than double-wild-type phenotype carriers (A-/Ile-). The present findings suggest that sCCL2 production possibly will be associated with the adiposity and polymorphic phenotypes of CCL2 and CCR2, in Mexican-Mestizos with IR.

Differential regulation of monocytic expression of leukotriene and lipoxin receptors.

INTRODUCTION: Lipoxygenase pathway yields both pro-inflammatory leukotrienes and pro-resolving lipoxins. The aim of the present study was to determine the effects of T-lymphocytes and pro-inflammatory stimuli on the expression levels of the lipoxin FPR2/ALX receptor, and the leukotriene BLT1 receptor in monocytes and macrophages, and to characterize LXA4-induced effects on pro-inflammatory mediators. METHODS: Human macrophages were co-cultured with activated CD4(+) cells. THP-1 cells were stimulated with different cytokines, LXA4 and supernatant from activated CD4(+) cells. mRNA was extracted for qPCR experiments and protein was analyzed by flow cytometry. RESULTS: Co-culture of macrophages with activated CD4(+) cells or their supernatants up-regulated macrophage FPR2/ALX expression but did not alter BLT1 receptor expression. Monocyte stimulation with IFN-γ up-regulated FPR2/ALX mRNA and protein levels, whereas BLT1 mRNA was down-regulated. Finally, LXA4 decreased mRNA levels of MMP-9, CXCL16, IL-1ß, and IL-8 in THP-1 cells. CONCLUSION: The present study shows that pro-inflammatory stimuli lead to FPR2/ALX expression. LXA4 induces an anti-inflammatory response, which could participate in the resolution of inflammation.

[Histological and molecular alterations in inflammatory myopathies]. / Alteraciones histológicas y moleculares en miopatías inflamatorias.

The histological findings in muscle biopsies of inflammatory myopathies have been divided into 2 groups: A) Endomisial infiltrates mainly by T CD8+, CD4+ and macrophages and B) Perivascular infiltrates by CD4+, B cells and macrophages. The first kind of infiltrate suggests an immune reaction against muscle fibers very common in PM and inclusion body myositis, On the other hand the perivascular infiltrate is a hallmark of DM. It has ben shown that autoantigens related with myopathies such as Mi-2, Jo-1, OJ, PL12, Ku, PM/Scl are able to suffer proteolytic cleavage by granzyme B and other stimulus induced by cytotoxic T cells. In this chapter we will review the histological and molecular findings of inflammatory myopathies but we will also discuss a special group of myopathies related to the presence of antibodies against the SRP complex, in particular the SRP72 and SRP54 antibodies, which are associated with a poor prognosis and clinical outcome and present an inadequate response to conventional treatment.