Osteopontin Genetic Polymorphism and Serum Levels in Patients with Systemic Lupus Erythematosus / 대한류마티스학회지

OBJECTIVE: A recent study suggested that a single nucleotide polymorphism (SNP) at position nt 9250 (C to T) in exon 7 of the osteopontin (OPN) gene is strongly associated with the susceptibility to systemic lupus erythematosus (SLE). This study examined the possible association between a single nucleotide polymorphism (SNP) at position nt 9250 (C to T) and SLE and measured the serum levels of OPN in Korean patients with SLE. METHODS: A total of 39 patients with SLE and 104 healthy controls were enrolled in this study. SNP located at position 9250 in the OPN gene were genotyped using the restriction fragment length polymorphism (RFLP). The serum levels of OPN in 39 patients with SLE and 20 healthy controls were determined by enzyme-linked immunosorbent assay. RESULTS: The allele frequencies of C and T at this position in patients with SLE were 34.6 and 65.4, whereas those in the controls were 20.7 and 79.3 (p<0.05). The serum levels of OPN in 39 patients with SLE were significantly higher than that in 20 healthy controls (49.13+/-26.71 versus 28.49+/-18.39 ng/ml, p<0.05). The increase in OPN concentration was associated with the SLE disease activity index (SLEDAI) score in all SLE patients (r=0.337, p<0.05). CONCLUSION: The allele frequencies of Eta-1/osteopontin were significantly associated with SLE. Moreover, the increased serum level of OPN is associated with the SLE disease activity. However, further investigation in larger groups in Korea will be needed.

Eta-1/Osteopontin Genetic Polymorphism is Associated with Urolithiasis in Koreans / 대한비뇨기과학회지

PURPOSE: Osteopontin(OPN) is one of the major non-collagenous bone matrix proteins produced by osteoblasts and osteolclasts, and it is also involved in the pathogenesis of urolithiasis. Single nucleotide polymorphisms(SNPs), as a tool for searching for the genetic markers of disease, have a large role in investigating the genetic markers of complex human diseases. The aim of this study is to investigate the association with this SNP at position nucleotide 9250(C-->T) in the OPN gene and the susceptibility to urolithiasis. We also compared the allele frequency of Koreans with those of Americans and Japanese. MATERIALS AND METHODS: A total of 161 urolithiasis patients and 104 healthy controls were studied. The SNPs located at position 9520 in the OPN gene were genotyped using restriction fragment length polymorphism(RFLP). The wild-type sequence contains a C while the polymorphism variant is a T(C-->T), which results in the appearance of an Alu I restriction site. RESULTS: The gene frequencies of C/C, C/T and T/T at position 9250 on the Eta-1/osteopontin gene in urolithiasis patients were 10.6%, 36.6% and 52.8%, respectively, compared with 6.7%, 27.9% and 65.8%, respectively, in the controls(p>0.05). The allele frequencies of C and T at this position in the urolithiasis patients were 28.9 and 72.1, respectively, whereas those in the controls were 20.7 and 79.3, respectively,(p<0.05). The allele frequencies found in the present study were compared with those coding SNPs described in the USA database; 60 and 39(USA) vs 20.7 and 79.3 (Korea), respectively(p<0.05). CONCLUSIONS: Those findings suggest there is no association of with Eta-1/osteopontin genetic polymorphism, but the allele frequencies were significantly associated with urolithiasis patients. We also observed difference of allele frequencies in our controls and in the USA controls and these differences may be caused by a difference in the incidence of urolithiasis patients between the two countries.

Expression of Eta-1 in Escherichia coli and Production of Monoclonal Antibody / 감염

BACKGROUND: Early T-lymphocyte activation-1 (Eta-1) is a secreted phosphoprotein which regulates a variety of cells involved in the immune and nonimmune systems. It is unique in the sense that it regulates various immune functions, as well as acting as an extracellular matrix protein. The Eta-1 gene has been mapped to the same genetic locus as the Rickettsia resistance gene (Ric), and Eta-1 expression is a part of an early T-dependent response to Orientia tsutsugamushi infection in susceptible hosts. In an initial effort to study Eta-1's mechanism of protection against Orientia tsutsugamushi infection, we attempted to produce Eta-1 in E. coli and to produce monoclonal antibodies against recombinant Eta-1. METHODS: Expression plasmids containing GST-Eta-1 were generated by cloning the polymerase chain reaction-amplified N-and C-terminal Eta-1 fragments into the cloning sites of pGEX-3X. The expressed protein was purified using a GST column and injected into BALB/c mice. Hybridoma clones reactive to Eta-1 were produced and analyzed with ELISA and Western blot. RESULTS: Expression plasmids containing GST-Eta-1 were generated by cloning the polymerase chain reaction-amplified N-and C-terminal Eta-1 fragments into the cloning sites of pGEX-3X. N-and C-terminal fragments of Eta-1 were generated as bacterially expressed GST fusion proteins. However, the expression of full-length Eta-1 was very poor. We immunized BALB/c mice with purified Eta-1 N-terminal fragments. Their spleen cells were used for cell fusion. We obtained two hybridoma cell lines secreting antibodies against Eta-1, but not against GST. Conclusions:We produced Eta-1 protein produced in E. coli. The expression of C-terminal Eta-1 fragments was poor, therefore it appeared that this part of Eta-1 was toxic to E. coli. We obtained monoclonal antibodies which were reactive in ELISA test and Western blot. These monoclonal antibodies could be useful in the analysis of the function of Eta-1 in the pathogenesis of tsutsugamushi disease as well as other diseases.