Eta-1/osteopontin genetic polymorphism and primary biliary cirrhosis

Relationships between Interleukin 18 -607 C/A and -137 G/C, Osteopontin -9250 C/T Genetic Polymorphisms and Systemic Inflammatory Response Syndrome in Coronary Artery Bypass Graft Surgery

Background and Objectives: Systemic inflammatory response syndrome (SIRS) is one of the most significant complications after on-pump heart surgery procedures. High cytokine levels have been shown after open-heart surgeries and a genetic predisposition seems to be an important underlying modulatory characteristic for SIRS. To investigate the association between interleukin 18 -607 C/A, interleukin 18 -137 G/C and osteopontin 9250 C/T genetic polymorphisms and SIRS in on-pump CABG patients. Materials and Methods: Two hundred consecutive elective on-pump CABG patients were recruited prospectively to the study. Genomic DNA was extracted from whole blood and genotyping was determined by sequence specific PCR or PCR-RFLP methods for related polymorphisms. Results: SIRS incidence was 60.2%, 38.1%, 18.9% on postoperative day 1, 2 and 3, respectively, in the whole study population. The SIRS rate on the second postoperative day was 13% and 43.4%, respectively, in osteopontin 9250 C/T T allele non-carriers and carriers (p = 0.004). WBC (White Blood Cell) counts were higher on day 2 and 3 in osteopontin 9250 C/T T allele carriers compared to non-carriers (day 2; 12.7 ± 4 vs. 10.5 ± 2.4 (p = 0.015), day 3; 11.8 ± 4 vs. 9.1 ± 4.7 (p = 0.035)). The average ICU stay was 3.1 ± 7.4, 1.28 ± 0.97 for IL 18-137 G/C C allele carriers and non-carriers, respectively (p = 0.003), and in the IL 18-137 G/C C allele carriers, SIRS developed in 42.2% by the second postoperative day whereas the rate was 57.8% in non-carriers (p = 0.025). Conclusions: The current research revealed a possible link between osteopontin 9250 C/T and IL18-137 G/C genetic polymorphism and SIRS and morbidity in on-pump CABG patients.

Osteopontin and interleukin-17A genes polymorphisms in Egyptian systemic lupus erythematosus patients: A relation to disease activity and severity

Osteopontin (OPN) is involved in the regulation of the immune response and is accused in the pathogenesis of several autoimmune diseases including systemic lupus erythematosus (SLE). An obvious link between OPN and T cells, particularly T helper 17 cells is reported, where OPN produced by dendritic cells supports interleukin-17 (IL-17) expression, contributing to pathology of autoimmune disorders. The aim of the study was to investigate the association of genotypes and alleles frequencies of OPN 9250 (rs1126616) and IL-17A 197 (rs2275913) genes polymorphisms with their serum levels, susceptibility, disease activity and severity in Egyptian SLE patients. A total of 80 SLE patients and 80 healthy subjects were enrolled. The PCR-RFLP technique was used to detect OPN 9250 C/T and IL-17A 197 G/A genes polymorphisms. Serum OPN and IL- 17 levels were measured by the enzyme-linked immunosorbent assay. OPN TT genotype and T allele were significantly detected in SLE patients more than controls (P = 0.003, P < 0.001 respectively). IL-17A AA genotype showed non-significant higher frequency in SLE patients than in their controls (P = 0.07). While only the A allele of IL-17A polymorphism was significantly elevated in patients (P = 0.048). There was statistical significant association between OPN CT and TT genotypes and both renal and mucocutaneous manifestations. Also IL-17A AG and AA genotypes was significantly associated with renal, mucocutaneous in addition to the hematological manifestations. Serum OPN levels were significantly increased with TT genotype while serum IL-17 levels were significantly increased with AA genotype. Disease activity and severity scores were significantly elevated with both OPN TT and IL-17A AA genotypes. In conclusion, OPN 9250 C/T and IL-17A 197 G/A genes polymorphisms and their serum levels seemed to have a role in pathogenesis of SLE.

Osteopontin Bridging Innate and Adaptive Immunity in Autoimmune Diseases

Osteopontin (OPN) regulates the immune response at multiple levels. Physiologically, it regulates the host response to infections by driving T helper (Th) polarization and acting on both innate and adaptive immunity; pathologically, it contributes to the development of immune-mediated and inflammatory diseases. In some cases, the mechanisms of these effects have been described, but many aspects of the OPN function remain elusive. This is in part ascribable to the fact that OPN is a complex molecule with several posttranslational modifications and it may act as either an immobilized protein of the extracellular matrix or a soluble cytokine or an intracytoplasmic molecule by binding to a wide variety of molecules including crystals of calcium phosphate, several cell surface receptors, and intracytoplasmic molecules. This review describes the OPN structure, isoforms, and functions and its role in regulating the crosstalk between innate and adaptive immunity in autoimmune diseases.

Clinical Characteristics of Concomitant Systemic Lupus Erythematosus and Primary Biliary Cirrhosis: A Literature Review

Although autoimmune diseases often coexist, concomitant cases of systemic lupus erythematosus (SLE) and primary biliary cirrhosis (PBC) are uncommon. In this review paper, 34 cases of SLE with concomitant PBC found in English and Japanese scientific literature and Japanese proceedings were reviewed and summarized, including cases with liver dysfunction complicated by SLE. Of the 34 reported concomitant cases of SLE and PBC, 97.1% (33/34) were females, and PBC was diagnosed initially in 69.0% (20/29), except for five cases in which both SLE and PBC were simultaneously diagnosed. Sjögren's syndrome was the most common autoimmune disease complicating concomitant SLE and PBC (23.5%, 8/34). Five deaths have been reported: two elderly patients died of liver failure because of the worsening of PBC, and another two patients died from pulmonary infection associated with SLE pharmacotherapy. It is uncertain whether concomitant cases occur by chance or share a common immunological or genetic basis.

Identification of secreted phosphoprotein 1 gene as a new rheumatoid arthritis susceptibility gene

OBJECTIVE

To evaluate the contribution of the SPP1 rs11439060 and rs9138 polymorphisms, previously reported as autoimmune risk variants, in the rheumatoid arthritis (RA) genetic background according to anti-citrullinated protein antibodies (ACPAs) status of RA individuals.

METHODS

We analysed a total of 11,715 RA cases and 26,493 controls from nine independent cohorts; all individuals were genotyped or had imputed genotypes for SPP1 rs11439060 and rs9138. The effect of the SPP1 rs11439060 and rs9138 risk-allele combination on osteopontin (OPN) expression in macrophages and OPN serum levels was investigated.

RESULTS

We provide evidence for a distinct contribution of SPP1 to RA susceptibility according to ACPA status: the combination of ≥3 SPP1 rs11439060 and rs9138 common alleles was associated mainly with ACPA negativity (p=1.29×10(-5), ORACPA-negative 1.257 (1.135 to 1.394)) and less with ACPA positivity (p=0.0148, ORACPA-positive 1.072 (1.014 to 1.134)). The ORs between these subgroups (ie, ACPA-positive and ACPA-negative) significantly differed (p=7.33×10(-3)). Expression quantitative trait locus analysis revealed an association of the SPP1 risk-allele combination with decreased SPP1 expression in peripheral macrophages from 599 individuals. To corroborate these findings, we found an association of the SPP1 risk-allele combination and low serum level of secreted OPN (p=0.0157), as well as serum level of secreted OPN correlated positively with ACPA production (p=0.005; r=0.483).

CONCLUSIONS

We demonstrate a significant contribution of the combination of SPP1 rs11439060 and rs9138 frequent alleles to risk of RA, the magnitude of the association being greater in patients negative for ACPAs.

Renal scarring and osteopontin gene C/T polymorphism in children with primary vesicoureteral reflux

We examined for osteopontin (OPN) gene C/T polymorphism in 78 patients (53 girls) with vesicoureteric reflux, with or without renal scarring. The T allele frequency was associated with a significantly increased risk (26.4 fold) of renal scarring.

Osteopontin expression in vitreous and proliferative retinal membranes of patients with proliferative vitreous retinopathy

AIM

To analyze osteopontin (OPN) expression in vitreous and proliferative retinal membranes of patients with proliferative vitreous retinopathy (PVR).

METHODS

A total of 54 vitreous fluid samples were obtained between 2009 and 2010, which contained 45 with PVR (group A) and 9 without PVR (group B). Enzyme-linked immunosorbent assay was applied to quantify the OPN concentrations in vitreous fluid. Four samples of proliferative retinal membrane were also obtained at the time of vitrectomy, and their contents of OPN were measured by Real-time RT-PCR.

RESULTS

The OPN levels in the vitreous fluid were 778.48±62.06ng/mL in group A and 452.99±32.52ng/mL in group B. The vitreous OPN levels in group A were significantly higher than those in group B and to rise by time in the early stages of PVR. The average OPN levels in the proliferative retinal membranes (F=0.14) were also higher than those in the retinal pigment cells (F=0) using Real-time RT-PCR.

CONCLUSION

The high vitreous and proliferative retinal membrane OPN levels in PVR suggest that OPN might promote the development of PVR. The vitreous OPN concentrations are rising by the time in the early phases of PVR.

A single-nucleotide polymorphism of the osteopontin gene may contribute to a susceptibility to Lewy body disease

In Lewy body disease, inflammation is discussed to be involved in the pathophysiological cascade. Osteopontin (OPN) is a multifunctional molecule, which is increased in inflammatory states. Here, we analyzed the allele frequency of two SNPs of the OPN gene, serum, and CSF OPN levels in Lewy body disease patients and controls. In accordance with our previous findings, we detected increased serum (P = 0.006) and CSF OPN levels (P = 0.0003) in the Lewy body disease cohort, compared to non-Lewy body disease subjects. The genotypic variation of SNP-66 was associated with the occurrence of Lewy body disease (odds ratio: 2.64, 95% CI 1.07-6.54, unadjusted P = 0.036). SNP+1239 was not related to Lewy body disease prevalence (odds ratio 1.61, 95% CI 0.66-3.91, P = 0.29). Genotype prevalence and OPN levels were not significantly related. These findings suggest that OPN is associated with the occurrence of Lewy body disease and SNP-66 may be a susceptibility factor.

Genes and (auto)immunity in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune cholestatic liver disease most commonly encountered in postmenopausal women; it is characterized by high-titer serum autoantibodies to mitochondrial antigens, elevated serum IgM, progressive destruction of intrahepatic bile ducts, and ultimately liver cirrhosis and failure. The cytopathic mechanisms leading to the selective destruction of intrahepatic cholangiocytes are still largely unknown. The current theory on the pathogenesis of PBC indicated that environmental factors might trigger autoimmunity in genetically susceptible individuals. In fact, genetic predisposition is critical to disease onset and progression, yet peculiar among autoimmune diseases, as indicated by the lack of a strong association with major histocompatibility complex haplotypes. Further, the recently reported concordance rate among monozygotic twins strengthens the importance of genetic factors, while also indicating that additional factors, possibly infectious agents or xenobiotics, intervene to trigger the disease. In this review, the available data regarding the genetic factors associated with PBC susceptibility and progression, as well as the available evidence regarding the immunomediated pathogenesis of PBC, will be critically illustrated and discussed.

A functional polymorphism in the Eta-1 promoter is associated with allele specific binding to the transcription factor Sp1 and elevated gene expression

Early T lymphocyte activator 1 (Eta-1), also known as Osteopontin, is a cytokine produced by macrophages and T lymphocytes. It is involved in the regulation of IL-12 and IL-10 expression in macrophages and stimulates the polarization of T cells to the Th1 subset. Three promoter polymorphisms of the human Eta-1 gene, -443T/C, -156delG/G, -66T/G, were investigated for possible influence on gene expression. Electrophoretic mobility shift assays (EMSA) with nuclear extract from the human myeloid leukaemia premonocyte cell line, THP-1, revealed sequence specific binding of the transcription factor Sp1 to the -66T allele but not the -66G allele, and haplotype -443C/-156G/-66T showed a marked increase in promoter activity of a luciferase reporter gene. Thus, a substitution of the T-base with G at position -66 in the Eta-1 promoter modulates the promoter activity of the Eta-1 gene, which might influence the Th1 versus Th2 balance. These observations are discussed in relation to a recently reported related observation on the same gene, and it is argued that discrepancies between reporter gene assays in the two studies may be due to the use of different cell lines and may reflect requirements for different transcription factors in cells involved in immune responses compared with other cells.

Expression of osteopontin correlates with portal biliary proliferation and fibrosis in biliary atresia

The acquired or perinatal form of biliary atresia is a Th1 fibro-inflammatory disease affecting both the extrahepatic and intrahepatic bile ducts. Osteopontin (OPN) is a Th1 cytokine implicated in several fibro-inflammatory and autoimmune diseases. We examined the expression of OPN in acquired biliary atresia in comparison to normal liver and several pediatric cholestatic liver diseases. We also assessed OPN expression by cultured human bile duct epithelial cells. We found that liver OPN mRNA and protein expression were significantly increased in biliary atresia versus normal and other cholestatic diseases. OPN expression in biliary atresia was localized to epithelium of proliferating biliary structures (ductules and/or ducts) and bile plugs contained therein. No portal biliary OPN expression could be demonstrated in normal liver, syndromic biliary atresia, biliary obstruction not due to biliary atresia, and idiopathic neonatal hepatitis. OPN expression by human bile duct epithelial cells in culture was responsive to IL-2 and TNF-alpha. Our results demonstrate an up-regulation of OPN expression by interlobular biliary epithelium in biliary atresia, which correlates with biliary proliferation and portal fibrosis. These findings suggest a role for OPN in the pathogenesis of biliary atresia.

From bases to basis: linking genetics to causation in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a multifactorial autoimmune disease with inherited and environmental components in pathogenesis. It is exceptional among autoimmune diseases in showing strong heritability according to familial occurrence and monozygotic twins concordance, yet with weak associations with the usual genetic risk elements for autoimmunity, such as the HLA alleles. Among the latter, there is risk (at least in some populations) conferred by HLA DRB1*08 and possibly some protection by DRB1*11. However, the inconsistency among studies on HLA is surprising, given that PBC is a relatively homogenous disease entity. Among non-HLA genes, some studies implicate polymorphisms of genes for cytotoxic T-lymphocyte antigen-4, interleukin-2, or interleukin-10; polymorphisms of the vitamin D receptor could synergize with low sunlight exposure to create deficiency of the immunoregulatory factor, activated vitamin D. A new lead is available from the finding in female subjects with PBC of an increase in the degree of monosomy of the X chromosome that is presumed to carry immune response genes. A further suggested source of inquiry is the apparent protection of African-American women from PBC. Finally, data on inheritance should be sought in PBC by descent methodology, rather than by cross-sectional association studies in cases and control subjects, and based on analysis of a large number of families with an affected member through a worldwide effort.

Polymorphisms in the osteopontin promoter affect its transcriptional activity

Understanding the molecular mechanisms that underlie regulation of transcription of the human osteopontin encoding gene (OPN) may help to clarify several processes, such as fibrotic evolution of organ damage, tumorigenesis and metastasis, and immune response, in which OPN overexpression is observed. With the aim to evaluate variants with functional effect on transcription, we have analyzed the promoter region and focused our investigation on three common variants present in the first 500 bp upstream of the transcription start site. Transfection of constructs carrying the four most frequent haplotypes relative to variants at -66, -156, and -443 fused to the luciferase reporter gene in a panel of different cell lines showed that one haplotype conferred a significantly reduced level of reporter gene expression in all tested cell lines. We describe that the -66 polymorphism modifies the binding affinity for the SP1/SP3 transcription factors, the -156 polymorphism is included in a yet uncharacterized RUNX2 binding site, and the -443 polymorphism causes differential binding of an unknown factor. The finding of differential effects of various combination of variants in haplotypes may contribute to explain data of association studies reported in several already published articles. Future association studies using haplotypes instead of single OPN variants will allow to achieve more accurate results referable to differential expression of OPN in several common diseases, in which OPN is considered a candidate susceptibility gene.

Inhibitor of kappaB kinase is required to activate a subset of interferon gamma-stimulated genes

IkappaB kinase (IKK), discovered as the major activator of NF-kappaB, plays additional roles in signaling. By using mouse embryo fibroblasts (MEFs) lacking both the alpha and beta subunits of IKK, we find that these proteins are required for induction of a major subset of IFNgamma-stimulated genes and that this requirement is independent of NF-kappaB activation. Furthermore, there is no defect in IFNgamma-stimulated signal transducer and activator of transcription 1 (Stat1) activation or function in the IKKalpha/beta-null MEFs. Therefore, although activated Stat1 dimers are necessary for the activation of these genes in response to IFNgamma, they are not sufficient. These results reveal an important additional pathway for IFNgamma-stimulated gene expression in which an NF-kappaB-independent function of IKK is required.