Osteopontin gene polymorphism in association with systemic lupus erythematosus in Chinese patients:

Investigation on the association between Osteopontin and Apolipoprotein E gene polymorphisms and vancomycin-induced acute kidney injury: A pharmacokinetic/pharmacogenetic study in critically ill patients

Vancomycin is a commonly administered antibiotic for various Gram-positive infections in critically ill patients. Vancomycin has a narrow therapeutic index and its main adverse drug reaction is acute kidney injury (AKI). In this regard, various pharmacokinetic parameters have been widely considered for therapeutic drug monitoring (TDM) purposes. Higher vancomycin trough concentration and area under the curve (AUC) values would be associated with higher rates of AKI. Therefore, dose adjustment based on targeted pharmacokinetic values would be essential to avoid toxicity and achieve optimal clinical response. However, there are numerous reports regarding the discrepancy between pharmacokinetic parameter values and AKI. In this regard, we examined the possible role of pharmacogenetics in vancomycin-induced AKI to distinguish patients who are genetically prone to AKI. In this cross-sectional study, polymorphisms of osteopontin (OPN) and Apolipoprotein E (APOE) along with pharmacokinetic parameters were assessed in 87 critically ill patients admitted to ICU wards and received vancomycin. The results indicated a significant difference in OPN and APOE genotype distribution between AKI and non-AKI patients (P = 0.001 and 0.02, respectively). Stepwise multivariate logistic regression analysis showed that patients with e2e3 genotype were 4.2-fold more prone to AKI (P = 0.029; OR = 4.2; 95 %CI = 1.2-15.7). Moreover, there was a significant correlation between pharmacokinetic parameters (calculated trough concentration, AUCτ, AUC24h, and t1/2) and vancomycin-induced AKI. Genotyping the patients for OPN and APOE polymorphisms before vancomycin initiation would be promising as a routine clinical practice to obtain an efficient clinical response and prevent vancomycin-induced AKI, especially in critically ill patients.

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.

Association of the rs1126616 and rs9138 Variants in the SPP1 Gene among Mexican Patients with Systemic Lupus Erythematosus and Lupus Nephritis

Systemic lupus erythematosus (SLE) is a multisystem disease considered a prototype of the main autoimmune disease and presents serious complications, such as lupus nephritis (LN), which generates a significant impact on morbidity and mortality. The SPP1 gene encodes the osteopontin (OPN) protein, which plays a crucial role in the regulation of inflammation and immunity. The variants rs1126616 and rs9138 of this gene have been associated with the inflammatory response. The study aims to analyze the association of the rs1126616 and rs9138 variants of the SPP1 gene in SLE Mexican-Mestizo patients without LN (SLE-LN). In this cross-sectional study, a total of 171 genomic DNA samples from SLE patients were clinically confirmed, of which 111 were SLE without LN, 60 were SLE with LN, and 100 healthy individuals were included as reference group. The rs1126616 variant was genotyped using PCR-RFLPs, and the rs9138 variant was genotyped using qPCR TaqMan. The TT genotype, the recessive model [OR 2.76 (95% CI 1.31-5.82), p = 0.011], and the T allele [OR 2.0 (95% CI 1.26-3.16), p = 0.003] of the rs1126616 variant are risk factors for SLE with LN. By contrast, the rs9138 variant did not show statistically significant differences among SLE patients stratified by LN. In our study of SLE Mexican-Mestizo patients with and without NL, demographic and clinical characteristics do not differ from other SLE populations, and the TT genotype of the rs1126616 variant of the SPP1 gene confers a risk factor for the presentation of LN. Otherwise, the rs9138 variant did not show association with NL.

Associations Between Osteopontin Variants and Systemic Lupus Erythematosus: A Meta-Analysis

Objective: Osteopontin (OPN) increases T-cell proliferation, interferon production, and CD40 ligand expression, which leads to B-cell proliferation and antibody production. This study was designed to determine whether OPN variants are associated with susceptibility to systemic lupus erythematosus [SLE]. Methods: We searched the Medline, Embase, and KoreaMed databases for available articles. We performed a meta-analysis on the association of OPN 707 T/C (rs1126616) at exon 6, 1083 G/A (rs112772) at the 3'-untranslated region (3'-UTR), 1239 C/A (rs9138) at 3'-UTR, and 9250 T/C (rs11229919) variants in exon 7 with susceptibility to SLE. Results: Ten studies from 9 articles with 2175 SLE patients and 3233 controls were included. The meta-analysis showed a significant association between SLE and the 707 T allele of the OPN 707 T/C variant (odds ratio [OR] = 1.522, 95% confidence interval [CI] = 1.101-2.105, p = 0.044). Stratification by ethnicity indicated an association between the OPN 707 T/C variant and SLE in European and Arab populations. The meta-analysis also revealed a significant association between the OPN 9250 C allele and SLE in the Asian and Arab populations. A significant association was also identified between the +1239 C allele of the OPN 1239 C/A variant and SLE (OR = 1.192, 95% CI = 1.008-1.410, p = 0.040). The meta-analysis indicated no allelic association between SLE and OPN 1083 G/A and the OPN 1239 C/A variants. Conclusions: The OPN 707 T/C variant is associated with SLE susceptibility in European and Arab populations and the OPN 9250 T/C variant is associated with SLE susceptibility in Asian and Arab populations. In addition, associations were found between the OPN 1239 C/A variant and SLE.

Genetics of osteopontin in patients with chronic kidney disease: The German Chronic Kidney Disease study

Osteopontin (OPN), encoded by SPP1, is a phosphorylated glycoprotein predominantly synthesized in kidney tissue. Increased OPN mRNA and protein expression correlates with proteinuria, reduced creatinine clearance, and kidney fibrosis in animal models of kidney disease. But its genetic underpinnings are incompletely understood. We therefore conducted a genome-wide association study (GWAS) of OPN in a European chronic kidney disease (CKD) population. Using data from participants of the German Chronic Kidney Disease (GCKD) study (N = 4,897), a GWAS (minor allele frequency [MAF]≥1%) and aggregated variant testing (AVT, MAF<1%) of ELISA-quantified serum OPN, adjusted for age, sex, estimated glomerular filtration rate (eGFR), and urinary albumin-to-creatinine ratio (UACR) was conducted. In the project, GCKD participants had a mean age of 60 years (SD 12), median eGFR of 46 mL/min/1.73m2 (p25: 37, p75: 57) and median UACR of 50 mg/g (p25: 9, p75: 383). GWAS revealed 3 loci (p<5.0E-08), two of which replicated in the population-based Young Finns Study (YFS) cohort (p<1.67E-03): rs10011284, upstream of SPP1 encoding the OPN protein and related to OPN production, and rs4253311, mapping into KLKB1 encoding prekallikrein (PK), which is processed to kallikrein (KAL) implicated through the kinin-kallikrein system (KKS) in blood pressure control, inflammation, blood coagulation, cancer, and cardiovascular disease. The SPP1 gene was also identified by AVT (p = 2.5E-8), comprising 7 splice-site and missense variants. Among others, downstream analyses revealed colocalization of the OPN association signal at SPP1 with expression in pancreas tissue, and at KLKB1 with various plasma proteins in trans, and with phenotypes (bone disorder, deep venous thrombosis) in human tissue. In summary, this GWAS of OPN levels revealed two replicated associations. The KLKB1 locus connects the function of OPN with PK, suggestive of possible further post-translation processing of OPN. Further studies are needed to elucidate the complex role of OPN within human (patho)physiology.

Association of Osteopontin gene single nucleotide polymorphism with lupus nephritis

AIM

To determine the association of single nucleotide polymorphism at 9250 C/T in exon 7 of the Osteopontin (OPN) gene among Egyptian patients with lupus nephritis (LN) and healthy controls and assess its relation with clinical and laboratory features in addition to both activity and chronicity indices in these patients.

MATERIALS AND METHOD

The study population includes 100 patients with LN and 100 age- and gender-matched controls. OPN gene 9250 C/T polymorphism was detected by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

We observed a significant difference in the frequencies of the OPN gene 9250 T allele between the patients with LN and the controls (74.5% vs 57.5%, P < .001); also, TT and CT + TT genotypes showed significant differences in frequencies between LN patients versus controls (59% vs 35% P = .005 and 90% vs. 80% P = .048, respectively). We also observed a non-significant association between OPN gene 9250 genotypes and each of the laboratory data and clinical features in addition to activity and chronicity indices in all studied LN patients. There were no statistically significant increased TT and CT + TT genotypes and T allele frequencies in LN patients with renal failure compared to those without renal failure. Logistic regression analysis revealed that only OPN (CT + TT) genotype could predict LN development in Egyptian patients.

CONCLUSION

TT and CT + TT genotypes and T alleles of OPN 9250 are considered risk factors for LN development in Egyptian systemic lupus erythematosus patients. However, these genotypes showed no association with each laboratory data and clinical feature or activity and chronicity indices in these patients. OPN 9250 (CT + TT) genotype could be used to predict LN development in SLE.

Osteopontin Gene Polymorphism and Urinary OPN Excretion in Patients with Immunoglobulin A Nephropathy

Osteopontin (OPN) is a glycoprotein involved in the pathogenesis of multiple autoimmune and inflammatory conditions. However, the association of variants of secreted phosphoprotein 1 gene (SPP1), which encodes OPN, with immunoglobulin A nephropathy (IgAN) has not been examined up to date. Moreover, the role of OPN in disease pathogenesis and clinical manifestations is not fully known. Therefore, the aim of the study was to determine the frequency of four single nucleotide polymorphisms (SNiPs) of SPP1 gene, as well as the urinary OPN excretion in IgAN patients and healthy controls. In total, 58 Caucasian patients with biopsy-proven IgAN and 184 gender-, age-, and ethnically-matched healthy controls were genotyped for rs1126616, rs1126772, rs9138, and rs7687316/rs3841116 polymorphisms by real time polymerase chain reaction (RT-PCR). Urinary OPN concentration was determined by enzyme-linked immunosorbent assay (ELISA) in 58 IgAN patients and 19 controls. SPP1 SNiPs, as well as urinary OPN excretion, were analyzed in relation to their possible associations with the clinicopathological parameters. The frequency of the minor TT/CT genotypes of rs1126616 was significantly higher in IgAN patients compared to controls (P = 0.0217). Similarly, the minor (CC/AC) genotypes and the C allele of rs9138 were more frequent in IgAN patients (P = 0.0425 and P = 0.0112, respectively). Moreover, these two SNiPs were associated with the higher urinary OPN excretion (P < 0.05). These findings suggest that rs1126616, as well as rs9138, may be associated with IgAN development, however future studies in this field are required.

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 Levels in Patients With Chronic Kidney Disease Stage 5 on Hemodialysis Directly Correlate With Intact Parathyroid Hormone and Alkaline Phosphatase

Chronic kidney disease stage 5 (CKD5) marks the fifth stage of renal failure, frequently causing dysregulation of bone and mineral metabolism. Challenges exist in evaluating and managing chronic kidney disease-mineral bone disorder (CKD-MBD) with the standard panel of biomarkers. Our objective was to profile osteopontin (OPN) in patients with CKD5 on maintenance hemodialysis (CKD5-HD) and elucidate its relationship to phosphorus (P), calcium (Ca2+), alkaline phosphatase (AP), and intact parathyroid hormone (iPTH) to improve understanding of the present model of CKD-MBD. Elevation of plasma OPN was seen in the CKD5-HD cohort (n = 92; median: 240.25 ng/mL, interquartile range [IQR]: 169.85 ng/mL) compared to a normal group (n = 49; median: 63.30 ng/mL, IQR: 19.20 ng/mL; p < .0001). Spearman correlation tests revealed significant positive correlations of OPN with iPTH (p < .0001; r = 0.561, 95% confidence interval = 0.397-0.690) and OPN with AP (p < .0001; r = 0.444, 95% confidence interval = 0.245-0.590) in CKD5-HD patients. Ultimately, OPN may play an integral role in the MBD axis, suggesting that it may be important to actively monitor OPN when managing CKD5-HD.

The role of osteopontin in kidney diseases

BACKGROUND

Osteopontin (OPN) is a pleiotropic glycoprotein expressed in various cell types in animals and in humans, including bone, immune, smooth muscle, epithelial and endothelial cells. Moreover, OPN is found in kidneys (in the thick ascending limbs of the loop of Henle and in distal nephrons) and urine. The protein plays an important role in mineralization and bone resorption. In addition, OPN is involved in the regulation of immunity and inflammation, angiogenesis and apoptosis. It was demonstrated that OPN and some OPN gene polymorphic variants are associated with the pathogenesis and progression of multiple disorders, such as cancer, autoimmune, neurodegenerative and cardiovascular diseases. Moreover, recent studies suggested that OPN is associated with the pathogenesis of renal failure.

METHODS

In this review, I briefly discussed the role of OPN and its gene polymorphisms in kidney physiology, as well as in various kidney diseases.

FINDINGS AND CONCLUSION

Most studies reported that OPN expression is elevated in urolithiasis, and also in acute and chronic kidney diseases, and in renal allograft dysfunction. Moreover, it was demonstrated that polymorphic variants of the OPN gene may be associated with renal failure. However, some reports suggested that OPN is essential for tubulogenesis, and that it inhibits calcium oxalate crystal formation and retention, nitric oxide synthesis, cell apoptosis and promotes cell regeneration. Thus, further studies are required to fully understand the role of OPN in kidney physiology and pathology. Eventually, these studies may result in the identification of OPN as a valuable marker for renal dysfunction prognosis and treatment.

Polymorphisms in the Osteopontin Are Associated with Susceptibility to Ankylosing Spondylitis in a Han Chinese Population

The aim of this study was to investigate whether osteopontin (OPN) variants are associated with susceptibility to ankylosing spondylitis (AS) in a Chinese population. Polymorphisms at the 9175th position in exon 7 of OPN and rs17524488 were genotyped using direct sequencing in 186 unrelated AS patients and 188 ethnically matched healthy controls. Serum concentration of OPN was measured by enzyme-linked immunosorbent assay (ELISA) in all participants. AS patients displayed significantly higher OPN serum levels than the controls (P < 001). A heterozygous, novel 9175 T>A in exon 7 of the OPN gene was found in this study. In healthy controls, subjects carrying the rs17524488 G/G genotype of the OPN display significantly higher OPN serum levels than the GG/GG genotype (P < 0.05). Plasma OPN level is implicated as an early diagnostic marker of AS. The novel 9175th- (exon 7) position polymorphism of OPN and rs17524488 were related to susceptibility to AS in a Chinese population, the rs17524488 G/G genotype may be involved in the pathogenesis of AS, and the precise molecular mechanism underlying the influence of OPN polymorphisms on the development of AS remains to be determined in the further prospective studies.

Application of Various Statistical Models to Explore Gene-Gene Interactions in Folate, Xenobiotic, Toll-Like Receptor and STAT4 Pathways that Modulate Susceptibility to Systemic Lupus Erythematosus

INTRODUCTION

In view of our previous studies showing an independent association of genetic polymorphisms in folate, xenobiotic, and toll-like receptor (TLR) pathways with the risk for systemic lupus erythematosus (SLE), we have developed three statistical models to delineate complex gene-gene interactions between folate, xenobiotic, TLR, and signal transducer and activator of transcription 4 (STAT4) signaling pathways in association with the molecular pathophysiology of SLE.

METHODS

We developed additive, multifactor dimensionality reduction (MDR), and artificial neural network (ANN) models.

RESULTS

The additive model, although the simplest, suggested a moderate predictability of 30 polymorphisms of these four pathways (area under the curve [AUC] 0.66). MDR analysis revealed significant gene-gene interactions among glutathione-S-transferase (GST)T1 and STAT4 (rs3821236 and rs7574865) polymorphisms, which account for moderate predictability of SLE. The MDR model for specific auto-antibodies revealed the importance of gene-gene interactions among cytochrome P450, family1, subfamily A, polypeptide 1 (CYP1A1) m1, catechol-O-methyltransferase (COMT) H108L, solute carrier family 19 (folate transporter), member 1 (SLC19A1) G80A, estrogen receptor 1 (ESR1), TLR5, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR), thymidylate synthase (TYMS). and STAT4 polymorphisms. The ANN model for disease prediction showed reasonably good predictability of SLE risk with 30 polymorphisms (AUC 0.76). These polymorphisms contribute towards the production of SSB and anti-dsDNA antibodies to the extent of 48 and 40%, respectively, while their contribution for the production of antiRNP, SSA, and anti-cardiolipin antibodies varies between 20 and 30%.

CONCLUSION

The current study highlighted the importance of genetic polymorphisms in folate, xenobiotic, TLR, and STAT4 signaling pathways as moderate predictors of SLE risk and delineates the molecular pathophysiology associated with these single nucleotide polymorphisms (SNPs) by demonstrating their association with specific auto-antibody production.

Correlation between circulating osteopontin level in systemic lupus erythematosus and disease activity and associations between osteopontin polymorphisms and disease susceptibility: A meta-analysis

Objective This study aimed to systemically review the evidence regarding the relationship between circulating blood osteopontin (OPN) level and systemic lupus erythematosus (SLE), correlation between serum OPN levels and SLE activity, and association between OPN polymorphisms and SLE susceptibility. Methods We conducted a meta-analysis on the serum/plasma OPN levels in SLE patients and healthy controls, correlation coefficients between the circulating OPN level and SLE Disease Activity Index (SLEDAI) in SLE patients, and the association between OPN polymorphisms and SLE risk. Results Nine studies with 1938 SLE patients and 3037 controls were included. Meta-analysis revealed that, compared with the control group, the OPN level was significantly higher in the SLE group (SMD = 0.965, 95% CI = 0.337-1.393, p = 0.001) and in the SLE group with renal disease (SMD = 2.219, 95% CI = 0.681-3.757, p = 0.005). Meta-analysis of correlation coefficients showed a trend of positive correlation between the circulating OPN level and SLEDAI (correlation coefficient = 0.590, 95% CI = -0.025 to 0.881, p = 0.059). While no association was found between SLE and the OPN 707 T/C and 1083 G/A polymorphisms, a significant association was identified between the OPN 1239 C allele and SLE (OR = 1.192, 95% CI = 1.008-1.410, p = 0.040), and between the OPN 9250 C allele and SLE in Asians (OR = 2.070, 95% CI = 1.570-2.730, p = 2.5 × 10^-7). Conclusions Our meta-analysis revealed a significantly higher circulating OPN level in SLE patients, a trend of positive correlation between OPN levels and SLE activity, and a significant association between OPN 1239 C/A and 9250 C/T polymorphisms, and SLE development.

Association of the osteopontin rs1126616 polymorphism and a higher serum osteopontin level with lupus nephritis

Osteopontin (OPN) is a chemokine-like glycoprotein that has a prominent role in regulating inflammation and immunity. OPN polymorphisms and elevated OPN levels are associated with systemic lupus erythematosus (SLE) in several populations. The aim of present study was to evaluate the association between the OPN rs1126616 polymorphism and OPN level with SLE susceptibility. A total of 163 SLE patients and 180 age-, gender- and ethnically matched controls were genotyped for the rs1126616 polymorphism by the polymerase chain reaction-restriction fragment length polymorphism method. Serum OPN levels were assayed by the enzyme-linked immunosorbent assay. There was no association between the OPN rs1126616 C/T polymorphism and SLE. The frequency of the OPN rs1126616 CT genotype was significantly higher in SLE patients with nephritis compared to SLE patients without nephritis and controls. Additionally, the frequency of TT genotypes was higher in SLE patients with nephritis compared to controls. The serum OPN levels were significantly higher in SLE patients compared to controls (50.6±22 vs. 35.6±15.8 ng/ml, P<0.001). Increased serum OPN levels were observed in SLE patients with lupus nephritis and joint symptoms. There was no correlation between OPN levels and the OPN rs1126616 polymorphism. The present data suggest that the CT and TT genotypes of the OPN rs1126616 polymorphism could be a risk factor for lupus nephritis. The OPN level is associated with SLE and certain SLE manifestations. However, there was no association between the OPN rs1126616 C/T polymorphism and SLE susceptibility.

Role of osteopontin in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a multisystemic disease, caused by a variety of factors, which lead to immunological abnormalities. Osteopontin (OPN) is a pleiotropic protein, important in bone remodeling and immune system signaling. OPN, produced by various cells, including immune cells, plays a key role in regulating T-helper 1/T-helper 2 balance, stimulating B lymphocytes to produce antibodies, regulating macrophages, neutrophils and inducing dendritic cells. OPN expression is influenced by genetic polymorphisms of its promoter, hormones and cytokines. Over expression of OPN has been associated with the pathogenesis of immune-mediated diseases. OPN has been implicated in the development of murine model of lupus and in humans with SLE. In this review, I will present current state of research on the role of OPN and OPN gene polymorphisms in pathogenesis and clinical course of SLE. A better understanding of the role of OPN in SLE will contribute to more precise diagnosis and treatment of the disease.

Osteopontin promoter polymorphisms are associated with susceptibility to gastric cancer

GOALS

To evaluate the significance of osteopontin (OPN) genotypes in the susceptibility to gastric cancer.

BACKGROUND

The expression of OPN has been correlated with development, invasiveness, metastasis, and survival of gastric cancer, but the role of polymorphisms in the OPN promoter has not been investigated.

STUDY

We enrolled 146 gastric cancer patients and 128 controls. DNA was extracted from peripheral blood leucocytes. Single-nucleotide polymorphisms (SNPs) in the OPN promoter (-66, -156, -443, -616, -1748, and -1776) were analyzed by pyrosequencing and direct sequencing methods. Logistic regression analyses were used to evaluate the associations between SNPs and development of gastric cancer.

RESULTS

SNP -443 C/C and -616 T/T of the OPN promoter were significantly associated with gastric cancer [odds ratio (OR)=2.88; 95% confidence interval (CI), 1.16-7.12 and OR=1.95; 95% CI, 1.35-2.82, respectively]. Analysis of the combined effect of OPN promoter SNPs revealed that the combination of SNP -443 (T/C or C/C) and SNP -616 (T/T or T/G) had the most significant association with gastric cancer (OR=3.95; 95% CI, 1.58-9.90).

CONCLUSIONS

Our results suggest that polymorphisms in the OPN promoter are associated with the development of gastric cancer, and the combination of SNP -443 (T/C or C/C) and -616 (T/T or T/G) most significantly increases susceptibility to gastric cancer.

The role of osteopontin (OPN/SPP1) haplotypes in the susceptibility to Crohn's disease

BACKGROUND

Osteopontin represents a multifunctional molecule playing a pivotal role in chronic inflammatory and autoimmune diseases. Its expression is increased in inflammatory bowel disease (IBD). The aim of our study was to analyze the association of osteopontin (OPN/SPP1) gene variants in a large cohort of IBD patients.

METHODOLOGY/PRINCIPAL FINDINGS

Genomic DNA from 2819 Caucasian individuals (n = 841 patients with Crohn's disease (CD), n = 473 patients with ulcerative colitis (UC), and n = 1505 healthy unrelated controls) was analyzed for nine OPN SNPs (rs2728127, rs2853744, rs11730582, rs11739060, rs28357094, rs4754 = p.Asp80Asp, rs1126616 = p.Ala236Ala, rs1126772 and rs9138). Considering the important role of osteopontin in Th17-mediated diseases, we performed analysis for epistasis with IBD-associated IL23R variants and analyzed serum levels of the Th17 cytokine IL-22. For four OPN SNPs (rs4754, rs1126616, rs1126772 and rs9138), we observed significantly different distributions between male and female CD patients. rs4754 was protective in male CD patients (p = 0.0004, OR = 0.69). None of the other investigated OPN SNPs was associated with CD or UC susceptibility. However, several OPN haplotypes showed significant associations with CD susceptibility. The strongest association was found for a haplotype consisting of the 8 OPN SNPs rs2728127-rs2853744-rs11730582-rs11439060-rs28357094-rs112661-rs1126772-rs9138 (omnibus p-value = 2.07×10⁻⁸). Overall, the mean IL-22 secretion in the combined group of OPN minor allele carriers with CD was significantly lower than that of CD patients with OPN wildtype alleles (p = 3.66×10⁻⁵). There was evidence for weak epistasis between the OPN SNP rs28357094 with the IL23R SNP rs10489629 (p = 4.18×10⁻²) and between OPN SNP rs1126616 and IL23R SNP rs2201841 (p = 4.18×10⁻²) but none of these associations remained significant after Bonferroni correction.

CONCLUSIONS/SIGNIFICANCE

Our study identified OPN haplotypes as modifiers of CD susceptibility, while the combined effects of certain OPN variants may modulate IL-22 secretion.

Male-only systemic lupus

OBJECTIVE

Systemic lupus erythematosus (SLE) is more common among women than men, a ratio of about 10 to 1. We undertook this study to describe familial male SLE within a large familial SLE cohort.

METHODS

SLE families (2 or more patients) were identified from the Lupus Multiplex Registry and Repository. Genomic DNA and blood samples were obtained using standard methods. Autoantibodies were determined by multiple methods. Medical records were abstracted for SLE clinical data. Fluorescent in situ hybridization (FISH) was performed with X and Y centromere-specific probes, and a probe specific for the Toll-like receptor 7 gene on the X chromosome.

RESULTS

Among 523 SLE families, we found 5 families in which all the SLE patients were male. FISH found no yaa gene equivalent in these families. SLE-unaffected primary female relatives from the 5 families with only-male SLE patients had a statistically increased rate of positive antinuclear antibodies compared to SLE-unaffected female relatives in other families. White men with SLE were 5 times more likely to have an offspring with SLE than White women with SLE, but there was no difference in this likelihood among Black men.

CONCLUSION

Because women in the all-male families had positive antinuclear antibodies, and men are more likely to have children with SLE, these data suggest genetic susceptibility factors that act only in men.

Osteopontin and the skin: multiple emerging roles in cutaneous biology and pathology

Osteopontin (OPN) is a glycoprotein expressed by various tissues and cells. The existence of variant forms of OPN as a secreted (sOPN) and intracellular (iOPN) protein and its modification through post-translational modification and proteolytic cleavage explain its broad range of functions. There is increasing knowledge which receptors OPN isoforms can bind to and which signaling pathways are activated to mediate different OPN functions. sOPN interacts with integrins and CD44, mediates cell adhesion, migration and tumor invasion, and has T helper 1 (Th1) cytokine functions and anti-apoptotic effects. iOPN has been described to regulate macrophage migration and interferon-alpha secretion in plasmacytoid dendritic cells. Both sOPN and iOPN, through complex functions for different dendritic cell subsets, participate in the regulation of Th cell lineages, among them Th17 cells. For skin disease, OPN from immune cells and tumor cells is of pathophysiological relevance. OPN is secreted in autoimmune diseases such as lupus erythematosus, and influences inflammation of immediate and delayed type allergies and granuloma formation. We describe that OPN is overexpressed in psoriasis and propose a model to study OPN function in psoriatic inflammation. Through cytokine functions, OPN supports immune responses against Mycobacteria and viruses such as herpes simplex virus. OPN is also implicated in skin tumor progression. Overexpression of OPN influences invasion and metastasis of melanoma and squamous cell carcinoma cells, and OPN expression in melanoma is a possible prognostic marker. As OPN protein preparations and anti-OPN antibodies may be available in the near future, in-depth knowledge of OPN functions may open new therapeutic approaches for skin diseases.

Osteopontin is associated with increased arterial stiffness in rheumatoid arthritis

Rheumatoid arthritis (RA) patients are characterized by increased arterial stiffness, an independent predictor of cardiovascular risk. It has been suggested that osteopontin (OPN), a cytokine involved in RA pathogenesis, might have vascular effects. To study a possible relationship between OPN and arterial stiffness, aortic pulse wave velocity (PWV) was measured by tonometry in 69 patients (41 with RA, 28 with systemic sclerosis [SSc]) and 18 healthy controls. Plasma OPN levels, oxidative stress markers, and endothelin 1 (ET-1) were assessed. OPN levels were significantly (P < 0.05) higher in RA (median 9.93, range 4.36-47.80 ng/mL) than in SSc (4.3, 2.1-19.7 ng/mL) or controls (5.2, 4.1-9.4 ng/mL). In RA patients, log-OPN was related to log-C-reactive protein (log-CRP) (r = 0.30, P < 0.05), age (r = 0.38, P < 0.01), Health Assessment Questionnaire (HAQ) (r = 0.58, P < 0.0001), and inversely related to total cholesterol (r = -0.33, P < 0.05) and apolipoprotein A (apoA) (r = -0.58, P < 0.001), but not to oxidative stress markers and ET-1. PWV was similar in RA (median 8.1, range 4.7-16.4 m/s) and SSc (median 8.7, range 7.1-13.1 m/s), but significantly greater (P < 0.01) than controls (median 7.5, range 4.1-10.4 m/s). Aortic PWV was related to log-OPN (r = 0.40, P < 0.01) only in RA patients. It also was related to age (r = 0.34, P < 0.05), mean blood pressure (r = 0.44, P < 0.001), and HAQ (r = 0.48, P < 0.001). In multiple regression analysis (r(2) = 0.36), including confounders, log-OPN remained a significant predictor (P < 0.05) of PWV in RA. Elevated plasma OPN levels are associated with increased arterial stiffness in RA patients, suggesting that this protein might represent a bridge protein between inflammation and the consequent joint damage and cardiovascular risk in RA patients.