Association between LEPR Genotype and Gut Microbiome in Healthy Non-Obese Korean Adults

The LEPR (leptin receptor) genotype is associated with obesity. Gut microbiome composition differs between obese and non-obese adults. However, the impact of LEPR genotype on gut microbiome composition in humans has not yet been studied. In this study, the association between LEPR single nucleotide polymorphism (rs1173100, rs1137101, and rs790419) and the gut microbiome composition in 65 non-obese Korean adults was investigated. Leptin, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels were also measured in all participants. Mean ± SD (standard deviation) of age, body mass index, and leptin hormone levels of participants was 35.2 ± 8.1 years, 21.4 ± 1.8 kg/m2, and 7989.1 ± 6687.4 pg/mL, respectively. Gut microbiome analysis was performed at the phylum level by 16S rRNA sequencing. Among the 11 phyla detected, only one showed significantly different relative abundances between LEPR genotypes. The relative abundance of Candidatus Saccharibacteria was higher in the G/A genotype group than in the G/G genotype group for the rs1137101 single nucleotide polymorphism (p=0.0322). Participant characteristics, including body mass index, leptin levels, and other lipid levels, were similar between the rs1137101 G/G and G/A genotypes. In addition, the relative abundances of Fusobacteria and Tenericutes showed significant positive relationship with plasma leptin concentrations (p=0.0036 and p=0.0000, respectively). In conclusion, LEPR genotype and gut microbiome may be associated even in normal-weight Korean adults. However, further studies with a greater number of obese adults are needed to confirm whether LEPR genotype is related to gut microbiome composition.

Association of lncRNA SOX2OT rs9839776 polymorphism with gastric cancer risk in Korean: Case-control study

Aberrant regulation of the long non-coding RNA SRY-box transcription factor 2 overlapping transcript (SOX2OT) has been reported in various diseases including gastric cancer (GC). However, an association between the well-studied rs9839776 single nucleotide polymorphism in SOX2OT and GC susceptibility has not been reported. This study aimed to evaluate the association between the rs9839776 single nucleotide polymorphism in SOX2OT and GC risk. Genotyping of rs9839776 was conducted using TaqMan genotyping assay for 460 patients with GC and 386 controls. We found that the dominant model (CT+TT) and rs9839776 T allele were significantly associated with decreased GC risk (P = .046, adjusted odds ratio [AOR] = 0.72, 95% confidence interval [CI] = 0.52-1.00 and P = .044, AOR = 0.74, 95% CI = 0.56-0.99, respectively). In addition, stratified analysis revealed that the dominant model (CT+TT) and rs9839776 T allele were significantly associated with decreased risk of lymph node metastasis-negative (P = .039, AOR = 0.67, 95% CI = 0.46-0.98 and P = .049, AOR = 0.71, 95% CI = 0.51-1.00, respectively) and tumor stage I (A+B)/II (A+B+C) (P = .028, AOR = 0.66, 95% CI = 0.50-0.96 and P = .041, AOR = 0.71, 95% CI = 0.52-0.99, respectively) GC. Our findings suggest that the rs9839776 T allele may be a protective factor against GC susceptibility. Further research is needed to clarify whether rs9839776 affects SOX2OT expression.

Comparative Pharmacokinetics Between a Fixed-Dose Combination of Pitavastatin/Valsartan 4/160 mg and the Corresponding Individual Components Through a Partial Replicated Crossover Design in Healthy Male Subjects

Hypertension and hyperlipidemia are often comorbid, requiring combination therapies of antihypertensive drugs and antihyperlipidemia drugs. Taking 1 fixed-dose combination (FDC) may increase patient compliance rather than taking each of the drugs separately. This study aimed to evaluate the pharmacokinetic bioequivalence between an FDC of pitavastatin/valsartan 4/160 mg and the corresponding individual components. Considering that valsartan is a highly variable drug for maximum plasma concentration (C_max ), an open-label, randomized, partial replicated crossover study was conducted in 54 healthy subjects. The subjects received a single oral dose of the FDC of pitavastatin/valsartan 4/160 mg in 1 period or the corresponding individual components in the other 2 periods. The geometric mean ratios and their 90%CIs of the FDC to the corresponding individual components for C_max and area under the concentration-time curve from time 0 to the last measurable time point were 1.05 (90%CI, 0.96-1.15) and 0.10 (90%CI, 0.95-1.04) for pitavastatin and 1.15 (90%CI, 1.06-1.25) and 1.06 (0.99-1.14) for valsartan, respectively. The geometric mean ratios (90%CIs) for area under the concentration-time curve from time 0 to the last measurable time point and C_max of both drugs were included in the bioequivalence criteria. In conclusion, the FDC of pitavastatin/valsartan 4/160 mg showed pharmacokinetic equivalence with the corresponding individual components.

The association between polymorphism of the long noncoding RNA, Plasmacytoma variant translocation 1, and the risk of gastric cancer

Genetic polymorphisms of plasmacytoma variant translocation 1 can affect various tumors including gastro-intestinal, sexual hormone sensitive cancers and lymphoma. Accumulated evidence have shown that plasmacytoma variant translocation 1 acts as an oncogene and tumor suppressor in various cancers. In fact, the rs13255292 and rs2608053 single nucleotide polymorphisms of plasmacytoma variant translocation 1are known to affect lymphoma; however, their effects on gastric cancer are primarily unknown. In this study, we evaluated the association between these plasmacytoma variant translocation 1 polymorphisms and the risk of gastric cancer.In the present study, 462 patients diagnosed with gastric cancer and 377 cancer-free controls were enrolled. The TaqMan genotyping assay was used to analyze the association between rs13255292 and rs2608053 single nucleotide polymorphisms and the risk of gastric cancer.The rs2608053 dominant model (CT + TT) was associated with a decreased risk of gastric cancer in T3 + T4 (odds ratio [OR] = 0.61, confidence interval (CI) = 0.41 - 0.92, P = .019), and stage III Gastric cancer subgroups (OR = 0.59, 95% CI = 0.38 - 0.91, P = .017) compared to the CC genotype. When stratified analysis by sex was carried out, the rs13255292 dominant model (CT + TT) had a significant association with an increased risk of gastric cancer in the female negative lymph node metastasis gastric cancer subgroup, compared to the CC genotype (OR = 1.96, 95% CI = 1.16 - 3.30, P = .012). The recessive model (TT) of rs13255292 was associated with an increased risk of gastric cancer in the male T3 + T4 gastric cancer subgroups compared to the CC + CT genotype (OR = 3.82, 95% CI = 1.02 - 14.33, P = .047). The dominant model (CT + TT) of rs2608053 was related to a decreased risk of gastric cancer in male T3 + T4 (OR = 0.57, 95% CI = 0.33 - 0.98, P = .042) and stage III gastric cancer subgroups (OR = 0.49, 95% CI = 0.27 - 0.89, P = .020) compared to the CC genotype.The rs13255292 and rs2608053 single nucleotide polymorphisms in plasmacytoma variant translocation 1 may contribute to susceptibility of gastric cancer. Further studies with more subjects and different ethnic groups are needed to validate our results.

Association of long noncoding RNA MALAT1 polymorphisms with gastric cancer risk in Korean individuals

Background

Metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1) drives tumorigenesis of various human cancers. However, the association between MALAT1 variants and gastric cancer (GC) risk is unknown. We performed a case‐control study to evaluate the possible association between rs619586 and rs3200401 SNPs in MALAT and GC risk.

Methods

Samples from 458 patients with GC and 381 controls were genotyped using the TaqMan genotyping assay.

Results

In stratified analyses, we observed that rs3200401 CT in the codominant model and CT+TT in the dominant model were associated with increased GC risk in male patients (CT: odds ratio [OR] = 1.81, 95% confidence interval [CI] = 1.09–3.01, p = 0.022; CT+TT: OR = 1.74, 95% CI = 1.07–2.83, p = 0.026), and the differentiated (CT: OR =1.79, 95% CI = 1.18–2.73, p = 0.007; CT+TT: OR = 1.76, 95% CI = 1.17–2.64, p = 0.007), and intestinal (CT: OR = 1.67, 95% CI = 1.11–2.49, p = 0.013; CT+TT: OR = 1.68, 95% CI = 1.14–2.47, p = 0.009) GC subgroups.

Conclusion

MALAT1 rs3200401 increases GC susceptibility and might affect GC development. Further studies are needed to validate our results in large populations and different ethnic groups.

Association Between lncRNA HULC rs7763881 Polymorphism and Gastric Cancer Risk

Purpose

Gastric cancer (GC) is one of the most common cancers in the world. Recently, several studies have suggested that single-nucleotide polymorphisms (SNPs) of long noncoding RNA (lncRNA) are associated with GC risk. However, the association of the lncRNA highly upregulated in liver cancer (HULC) SNP with GC risk is not yet known. The aims of this study were to evaluate the association between HULC rs7763881 SNP and the risk of GC and GC subgroups via a case–control study.

Patients and Methods

rs7763881 was genotyped using TaqMan genotyping assay with 459 GC patients and 379 controls.

Results

A significant association between HULC rs7763881 SNP and GC risk was not found. However, after adjustment for age and gender, the rs7763881 recessive model (CC) showed a significant association with an increased GC risk in the undifferentiated (odds ratio (OR) = 1.85, 95% confidence interval (CI) = 1.17–2.94, P = 0.009), diffuse-type GC (OR = 1.72, 95% CI = 1.05–2.82, P = 0.033), LNM-positive (OR = 2.02, 95% CI = 1.24–3.27, P = 0.004), T3/T4 (OR = 1.75, 95% CI = 1.05–2.91, P = 0.032), and tumor stage III (OR = 2.01, 95% CI = 1.17–3.45, P = 0.011) subgroups when compared to the rs7763881 combined genotypes (AA+AC). Furthermore, after adjusting for age and gender, the rs7763881 additive model (CC) indicated a significantly higher GC risk than rs7763881 AA genotype in the undifferentiated (OR = 1.96, 95% CI = 1.15–3.32, P = 0.013), diffuse-type GC (OR = 2.08, 95% CI = 1.23–3.52, P = 0.004), and LNM-positive (OR = 2.00, 95% CI = 1.14–3.49, P = 0.016) subgroups.

Conclusion

Our findings suggest that the HULC rs7763881 SNP is associated with increased susceptibility to GC. However, further studies are required to validate our results in large populations as well as different ethnic groups.

Correlations between Genetic Polymorphisms in Long Non-Coding RNA PRNCR1 and Gastric Cancer Risk in a Korean Population

We evaluated the association between prostate cancer non-coding RNA 1 (PRNCR1) polymorphisms and the risk of developing gastric cancer (GC) and GC subgroups in Korea. A case-control study was conducted with 437 GC patients and 357 healthy controls using a TaqMan genotyping assay. A chi-squared test, binary logistic regression, and genetic models were used to explore the association between five PRNCR1 polymorphisms and GC risk. After adjusting for gender and age, overall analyses using the recessive model indicated that the rs13252298 GG genotype was significantly associated with increased risk of intestinal-type gastric cancer (IGC). In the stratification analyses, the recessive model indicated that the rs1016343 TT genotype was significantly associated with decreased GC risk in individuals aged <60 years showing lymph node metastasis (LNM)-negative results. The rs13252298 GG genotype in the recessive model showed increased GC risk in subjects aged ≥60 years showing LNM-positive results and those aged ≥60 years in tumor stage III. In the dominant model, the rs16901946 combined genotype (AG/GG) was significantly associated with increased GC risk in subjects aged <60 years with tumor stage III. In the recessive model, the rs16901946 GG genotype was associated with decreased risk of GC and IGC in males aged ≥60 years. Thus, genetic variations in PRNCR1 may contribute to susceptibility to GC.

Comparison of tadalafil pharmacokinetics after administration of a new orodispersible film versus a film-coated tablet

Background

An orodispersible film (ODF) of tadalafil may provide increased convenience for erectile dysfunction (ED) patients as compared to conventional tablet formulations. In this study, we aimed to compare the pharmacokinetic, safety, and tolerability profiles of a newly developed ODF formulation of tadalafil to those of a film-coated tablet (FCT) of tadalafil.

Materials and methods

This study was conducted in healthy male subjects using an open-label, randomized sequence, two-period, two-formulation, single-dose, crossover design. The subjects were randomly assigned to one of two sequences of the two formulations: both the test drug (ODF) and the reference drug (FCT) contained 20 mg of tadalafil. Blood samples were collected up to 72 h after administration. Plasma concentrations of tadalafil were analyzed using liquid chromatography-tandem mass spectrometry. Geometric mean ratios (GMRs) of the ODF to FCT formulations and their 90% CIs for the pharmacokinetic parameters were estimated. Safety and tolerability were assessed throughout the study.

Results

Forty healthy male subjects were enrolled, and 36 of these completed the study. The GMRs (90% CIs) of the maximum plasma concentration and the area under the plasma concentration-time curve from time zero to the time of the last quantifiable concentration for tadalafil were 0.927 (0.882-0.974) and 0.972 (0.918-1.029), respectively. Both ODF and FCT formulations were well tolerated, and no clinically significant changes from the baseline were observed after dosing.

Conclusion

The pharmacokinetics of the tadalafil ODF formulation did not differ significantly from those of the FCT formulation. Furthermore, the safety and tolerability profiles of the ODF formulation were comparable to those of the FCT formulation. Therefore, this tadalafil ODF formulation offers a convenient treatment option for patients with erectile dysfunction.

Mitochondrial NADH Dehydrogenase Subunit 3 (MTND3) Polymorphisms are Associated with Gastric Cancer Susceptibility

Accumulating evidence indicates that mitochondrial DNA alterations contribute to cancer development and progression. In this study, we evaluated the relationship between polymorphisms of mitochondrial NADH dehydrogenase subunit 3 (MTND3) and the risk of gastric cancer (GC). Five single nucleotide polymorphisms (SNPs; rs28358278, rs2853826, rs201397417, rs41467651, and rs28358275) were identified and genotyped in 377 patients with GC patients and 363 controls by direct sequencing. The rs41467651 T allele was significantly associated with GC risk [adjusted odds ratio (OR) = 2.11, 95% confidence interval (CI) = 1.25-3.55, P = 0.005). In stratified analysis, rs28358278, rs2853826, and rs41467651 were associated with subgroups of GC, with the rs28358278 G, rs2853826 T, and rs41467651 T alleles associated with an increased GC risk in females (adjusted OR = 1.70, 95% CI = 1.08-2.69, P = 0.023; adjusted OR = 1.78, 95% CI = 1.11-2.85, P = 0.016; adjusted OR = 2.07, 95% CI = 1.04-4.12, P = 0.038, respectively). The rs441467651 T allele was also related with GC risk in diffuse-type subjects compared to that of controls (adjusted OR = 2.61, 95% CI = 1.43-4.89, P = 0.002). In addition, The rs441467651 T allele was significantly related with increased GC risk regardless of lymph node metastasis (LNM), T classification, and tumor stage compared to that of controls (adjusted OR = 2.00, 95% CI = 1.12-3.55, P = 0.019 in LNM-negative subjects; adjusted OR = 2.10, 95% CI = 1.05-4.22, P = 0.0379 in LNM-positive subjects; adjusted OR = 1.82, 95% CI = 1.02-3.24, P = 0.042 in T1/T2 subjects; adjusted OR = 2.60, 95% CI = 1.29-5.24, P = 0.007 in T3/T4 subjects; adjusted OR = 1.91, 95% CI = 1.09-3.34, P = 0.025 in tumor stage I (A+B)/II (A+B+C) subjects; adjusted OR = 2.36, 95% CI = 1.12-5.13, P = 0.025 in tumor stage III (A+B+C) subjects) compared to that of controls. Our findings suggest that the rs28358278, rs2853826, and rs41467651 polymorphisms of MTND3 increase the susceptibility to GC development.

Association between Promoter Polymorphisms of TFF1, TFF2, and TFF3 and the Risk of Gastric and Diffuse Gastric Cancers in a Korean Population

Gastric cancer is one of the most common cancers in the world. The aims of this study were to evaluate the association between polymorphisms in TFF gene family, TFF1, TFF2, and TFF3 and the risk of gastric cancer (GC) and GC subgroups in a Korean population via a case-control study. The eight polymorphisms in TFF gene family were identified by sequencing and genotyped with 377 GC patients and 396 controls by using TaqMan genotyping assay. The rs184432 TT genotype of TFF1 was significantly associated with a reduced risk of GC (odds ratio, [OR) = 0.45; 95% confidence interval, [CI] = 0.25-0.82; P = 0.009), more protective against diffuse-type GC (OR = 0.20; 95% CI = 0.05-0.89; P = 0.035) than GC (OR = 0.34; 95% CI = 0.14-0.82; P = 0.017) in subjects aged < 60 yr, and correlated with lymph node metastasis negative GC and diffuse-type GC (OR = 0.44; 95% CI = 0.23-0.86; P = 0.016 and OR = 0.20; 95% CI = 0.05-0.87; P = 0.031, respectively). In addition, a decreased risk of lymph node metastasis negative GC and diffuse-type GC was observed for rs225359 TT genotype of TFF1 (OR = 0.46, 95% CI = 0.24-0.88; P = 0.020 and OR = 0.21, 95% CI = 0.05-0.88; P = 0.033, respectively). These findings suggest that the rs184432 and rs225359 polymorphisms in TFF1 have protective effects for GC and contribute to the development of GC in Korean individuals.

Association between polymorphisms in APE1 and XRCC1 and the risk of gastric cancer in Korean population

The DNA repair system plays a pivotal role in maintaining genomic integrity and protection against mutations that could lead to cancer development. The aim of this study was to explore the association between common polymorphisms of DNA repair genes, APE1 (rs1760944 and rs1130409) and XRCC1 (rs1799782, rs25487, and rs25489), and gastric cancer (GC) risk in the Korean population. We conducted a case-control study of 368 GC patients and 398 controls by using TaqMan genotyping assay. None of the polymorphisms was associated with the risk of GC. Further analysis showed a lack of association between APE1 and XRCC1 polymorphisms or haplotypes and the risk of GC and GC subgroups. The heterozygous CT genotype of XRCC1 rs25487 was related to 1.94 times increased risk of lymph node metastasis (LNM) in diffuse type GC compared to the XRCC1 rs25487 CC genotype (adjusted OR = 1.94, 95% CI = 1.06-3.53, P = 0.031) after adjusting for gender and age, whereas the remaining polymorphisms showed no association with GC or GC subgroups. This result suggests that genetic variation of XRCC1 rs25487 could be a risk factor for LNM in diffuse type of GC in the Korean population.

MicroRNA-222 regulates MMP-13 via targeting HDAC-4 during osteoarthritis pathogenesis

Background

Even though increasing evidences on miRNA involvement in human pathological responses, the distinct roles and related mechanisms of miRNAs in the pathology of osteoarthritis (OA) are not yet fully understood.

Method

RNA levels or protein levels of Apoptotic genes, HDACs, MMP-13, and miRNAs in human chondrocytes isolated from normal biopsy sample and OA cartilages were analyzed by real-time PCR or western blotting. Exogenous modulation of miR-222 level was performed using delivery of its specific precursor or specific inhibitor and target validation assay was applied to identify its potent target. In vivo study using DMM mice model was performed and assessed the degree of cartilage degradation.

Results

According to miRNA profiling, miR-222 was significantly down-regulated in OA chondrocytes. Over-expression of miR-222 significantly suppressed apoptotic death by down-regulating HDAC-4 and MMP-13 level. Moreover, 3′-UTR reporter assays showed that HDAC-4 is a direct target of miR-222. The treatment of chondrocytes with the HDAC inhibitor, trichostatin A (TSA), suppressed MMP-13 protein level and apoptosis, whereas the over-expression of HDAC-4 displayed opposite effects. The introduction of miR-222 into the cartilage of medial meniscus destabilized mice significantly reduced cartilage destruction and MMP-13 level.

Conclusion

Taken together, our data suggest that miR-222 may be involved in cartilage destruction by targeting HDAC-4 and regulating MMP-13 level.

•

MiR-222 controls OA pathogenesis by targeting HDAC-4.

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HADC-4 regulated by miR-222 modulates MMP-13 expression during cartilage destruction.

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Our study indicates the possibility that miR-222 could act as a protective factor against OA.

Genome-wide expression profiling of complex regional pain syndrome

Complex regional pain syndrome (CRPS) is a chronic, progressive, and devastating pain syndrome characterized by spontaneous pain, hyperalgesia, allodynia, altered skin temperature, and motor dysfunction. Although previous gene expression profiling studies have been conducted in animal pain models, there genome-wide expression profiling in the whole blood of CRPS patients has not been reported yet. Here, we successfully identified certain pain-related genes through genome-wide expression profiling in the blood from CRPS patients. We found that 80 genes were differentially expressed between 4 CRPS patients (2 CRPS I and 2 CRPS II) and 5 controls (cut-off value: 1.5-fold change and p<0.05). Most of those genes were associated with signal transduction, developmental processes, cell structure and motility, and immunity and defense. The expression levels of major histocompatibility complex class I A subtype (HLA-A29.1), matrix metalloproteinase 9 (MMP9), alanine aminopeptidase N (ANPEP), l-histidine decarboxylase (HDC), granulocyte colony-stimulating factor 3 receptor (G-CSF3R), and signal transducer and activator of transcription 3 (STAT3) genes selected from the microarray were confirmed in 24 CRPS patients and 18 controls by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). We focused on the MMP9 gene that, by qRT-PCR, showed a statistically significant difference in expression in CRPS patients compared to controls with the highest relative fold change (4.0±1.23 times and p = 1.4×10⁻⁴). The up-regulation of MMP9 gene in the blood may be related to the pain progression in CRPS patients. Our findings, which offer a valuable contribution to the understanding of the differential gene expression in CRPS may help in the understanding of the pathophysiology of CRPS pain progression.

TiO2 nanotube stimulate chondrogenic differentiation of limb mesenchymal cells by modulating focal activity

Vertically aligned, laterally spaced nanoscale titanium nanotubes were grown on a titanium surface by anodization, and the growth of chondroprogenitors on the resulting surfaces was investigated. Surfaces bearing nanotubes of 70 to 100 nm in diameter were found to trigger the morphological transition to a cortical actin pattern and rounded cell shape (both indicative of chondrocytic differentiation), as well as the up-regulation of type II collagen and integrin beta4 protein expression through the down-regulation of Erk activity. Inhibition of Erk signaling reduced stress fiber formation and induced the transition to the cortical actin pattern in cells cultured on 30-nm-diameter nanotubes, which maintained their fibroblastoid morphologies in the absence of Erk inhibition. Collectively, these results indicate that a titanium-based nanotube surface can support chondrocytic functions among chondroprogenitors, and may therefore be useful for future cartilaginous applications.

Significant association between IL-17F promoter region polymorphism and susceptibility to asthma in a Korean population

BACKGROUND

Individual differences in susceptibility to asthma would be expected because of common DNA variants of single nucleotide polymorphisms (SNPs) across populations. The pro-inflammatory cytokine IL-17F has homology with the IL-17 motif and induces the expression of other inflammatory cytokines in airway epithelial cells. This study aimed to identify IL-17F gene polymorphisms and to determine a possible association between these polymorphisms and susceptibility to asthma through a case-control study in a Korean population.

METHODS

We identified SNPs in the IL-17F gene by sequencing. Genotyping was conducted using the high-resolution melting (HRM) method on 424 asthma patients and 548 healthy controls.

RESULTS

The genotype and allele frequencies of rs1889570 SNP were significantly different between asthma patients and healthy controls (p = 0.001 and 0.002, respectively). The rs1889570 SNP genotype was also positively associated with the number of peripheral blood eosinophils in asthma patients (p = 0.03). The frequencies of haplotypes AA (p = 0.01), GG (p = 0.01) and AG (p = 0.006) were significantly different between asthma patients and healthy controls.

CONCLUSIONS

In this study, we confirmed that the rs1889570 polymorphism of the IL-17F gene is associated with susceptibility to asthma in a Korean population.

The potential role of VPREB1 gene copy number variation in susceptibility to rheumatoid arthritis

Although the etiology of rheumatoid arthritis (RA) remains unknown, it has been widely suggested that RA has a genetic background. In humans, a copy number loss of 22q11.2, a region harboring the VPREB1 gene, has been suggested to be associated with several immunologic disorders, but there has been no study on the copy number variation (CNV) of the VPREB1 and its potential association with RA. Here, we explored the association between the RA and the CNV of the VPREB1 gene by performing genomic quantitative PCR and quantification of B cell subsets in RA patients and controls. The proportion of the individuals with <2 copies of the VPREB1 gene was significantly higher in the patient group than that in the controls (12.9% vs 0.9%, p<0.0001), while that of the individuals with >2 copies was lower in the patient group than that in the controls (1.7% vs 18.9%, p<0.0001). The odds ratio (OR) of the individuals with <2 copies was significantly higher compared with the odds ratio of those individuals with 2 copies (OR=12.1, 95% confidence interval (CI) 2.8-51.6). Likewise, the OR of the individuals with >2 copies was significantly lower than the OR of those individuals with 2 copies (OR=0.09, 95% CI 0.03-0.3). We also found that the proportion of CD21⁻CD23⁻ B cells was significantly higher in the RA patients compared with that of the controls (11.9% vs 5.7%, p=0.002), but the proportion of CD21+CD23+ cells was significantly lower in the RA patients (26.2% in RA vs 34.9% in the controls, p=0.005). To the best of our knowledge, this is the first evidence showing the association between a low copy number of the VPREB1 gene and RA, and this may help understanding the pathogenesis of RA and other autoimmune disorders.

Polymorphisms of COTL1 gene identified by proteomic approach and their association with autoimmune disorders

To select candidate genes, we attempted to comparative analysis of protein levels between rheumatoid arthritis (RA) patients and healthy controls by two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-TOF-MS). We identified 17 proteins that showed up- or down-regulated spots in RA patients. We found that coactosin-like1 (COTL1) were highly expressed in RA patients compared with healthy controls. We performed a case-control study to determine whether the COTL1 gene polymorphisms were associated with RA and systemic lupus erythematosus (SLE). The genotype frequency of c.-1124G>T and the allelic frequency of c.484G>A in RA patients, and the genotype frequency of c.484G>A in SLE patients were significantly different from healthy controls (P=0.009, 0.027, and 0.025, respectively). We also investigated the correlation with the levels of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibody in RA patients, and anti-nuclear antibodies (ANA) in SLE patients. The c.484G>A polymorphism in RA patients has significant association with the levels of anti-CCP antibody (P=0.03). Our findings demonstrated that c.-1124G>T and c. 484G>A polymorphisms of the COTL1 gene might be associated with the genetic susceptibility of autoimmune disorders.

Identification of functionally important residues of human thrombopoietin

Thrombopoietin (TPO) is a megakaryocyte growth and differentiation factor. It consists of a characteristic two domain structure. The amino-terminal domain of TPO has a sequence homology with erythropoietin and is required for the binding and activation of its receptor c-Mpl. To determine the functionally important regions interacting with its receptor, a series of site-directed mutants of TPO were constructed based on a three-dimensional model of the amino-terminal domain. Two strategies of mutagenesis were employed: 1) nonnative N-linked glycosylation scan of 12 residues predicted to be on the surface, and 2) alanine replacement scan of mostly charged 44 amino acid residues. Each TPO mutein was transiently expressed in COS7 cells, and the specific bioactivity of the TPO protein secreted into the culture medium was measured using a recombinant BaF3 cell line expressing human c-Mpl. Four alanine substitutions at Arg10, Pro42, Glu50, and Lys138 nearly or completely abolished the activity, whereas the mutation at Arg14 slightly decreased the activity, suggesting that these residues are functionally important in interacting with its receptor. These residues mapped to helix A, loop AB, and helix D. Sequence comparison between human TPO and other mammalian TPO showed that the identified residues are completely conserved among the species. However, unlike the recent report on the mutational analysis of TPO, alanine substitutions at Lys52, Lys59, Arg136, and Arg140 did not affect the TPO activity significantly in our system. The identified receptor binding regions of TPO are analogous to those of human growth hormone and erythropoietin. Based on the similarity of these three cytokines, we propose that Lys138 of helix D and Pro42 and Glu50 of loop AB may constitute one binding region, whereas Arg10 and Lys14 of helix A may constitute the other binding region to dimerize the receptors.