Coffee consumption affects kidney function based on GCKR polymorphism in a Korean population

Kidney function can be preserved through pharmacological interventions and nonpharmacological strategies, such as lifestyle and dietary adjustments. Among these, coffee has been linked to protective effects on kidney function. However, few studies have investigated the effect of coffee consumption on kidney function according to specific genes. We hypothesized that the impact of coffee consumption on kidney function might vary depending on GCKR polymorphism. GCKR rs1260326 polymorphism was examined using the Korean genome and epidemiology data from 656 chronic kidney disease (CKD) cases and 38,540 individuals without CKD (non-CKD). GCKR polymorphism has been previously associated with both coffee consumption and kidney function in Europeans. We replicated the associations between GCKR rs1260326 and coffee consumption and kidney function in Korean individuals. We also explored the effect of coffee consumption on kidney function by multivariate logistic regression analysis. Individuals with the rs1260326 (TC/CC) genotype did not experience significant changes in CKD risk based on their coffee consumption habits. In contrast, individuals with the TT genotype exhibited a significantly lower risk of CKD based on coffee consumption. Interestingly, in the non-CKD group, a beneficial effect on estimated glomerular filtration rate was observed in individuals with the T allele as coffee consumption increased. Our findings supported the hypothesis and revealed that the impact of coffee consumption habits on kidney function may vary based on the GCKR rs1260326 genotype of Korean individuals.

Association of IGF1R polymorphisms with kidney function-related traits

BACKGROUND

Unimpaired kidney function is important for maintaining a healthy state of homeostasis in the body. A genome-wide association study (GWAS) conducted on kidney function-associated traits and novel loci of Japanese subjects found that insulin-like-growth factor 1 receptor (IGF1R) gene variants associated with replication were responsible for all three kinds of kidney functions and satisfied the Bonferroni significance level.

OBJECTIVE

This study aimed to investigate whether a comparable relationship exists in the Korean population.

METHOD

This study replicated three SNPs (rs28657002, rs10794486, and rs4966025) and conducted a linear regression analysis between 46 SNPs in the IGF1R gene and three kidney function-related traits, namely blood urea nitrogen (BUN), creatinine, and estimated glomerular filtration rate (eGFR) in Koreans.

RESULTS

The IGF1R gene was found to be replicated with a significant correlation in Koreans and was extended to the entire gene region to confirm its association with kidney-related functions. Three SNPs in IGF1R were replicated (rs28657002, BUN, P = 3.39 × 10-4; rs10794486, creatinine, P = 5.79 × 10-6; rs4966025, eGFR, P = 1.57 × 10-5) and five SNPs (rs28657002, rs10794486, rs4966025, rs12439557, and rs11247372) showed common significance among the three traits. Additionally, two significant SNPs (rs11857366 and rs28657002) showed the potential to affect IGF1R expression.

CONCLUSIONS

The results suggest that genetic polymorphisms in the IGF1R replicated previous studies and could affect kidney function. The results of this study will further enhance our understanding of how genetic differences in individuals affect kidney function-related traits.

A genome-wide association scan reveals novel loci for facial traits of Koreans

DNA-based prediction of externally visible characteristics (EVC) with SNPs is one of the research areas of interest in the forensic field. Based on a previous study performing GWAS on facial traits in a Korean population, herein, we present results stemming from GWA analysis with KoreanChip and novel genetic loci satisfying genome-wide significant level. We discovered a total of 20 signals and 12 loci were found to have novel associations with facial traits, including six loci located in intergenic regions and six loci located at UBE2O, HECTD2, CCDC108, TPK1, FCN2, and FRMPD1. Additionally, we performed a polygenic score analysis for 33 distance-related traits in facial phenotyping and determined genetic relationships between facial traits and SNPs using the GCTA program. The results of the current study offer an understanding of how facial morphology is influenced by complex genetic structures and provide insights into forensic investigation and population genetics.

The KL genetic polymorphisms Associated with type 2 diabetes Mellitus

Growing number of research studies have shown that an anti-ageing gene Klotho (KL) is closely associated with Type 2 Diabetes Mellitus (T2DM). In this study, the association is genetically analyzed with single nucleotide polymorphism (SNP) of KL found in T2DM case of an Asian cohort. KL SNP information was obtained from a big database of the Korean Association Resource (KARE) from which 20 KL SNPs were available. Statistical analyses were conducted based on the 3 genetic models, such as additive, dominant, and recessive. Of the 20 KL SNPs, 12 SNPs were found to be significantly associated with T2DM in both of additive and dominant models. Odds ratios of the KL SNPs indicate increased susceptibility to T2DM in additive and dominant models. Significant association of KL with T2DM was further analyzed using imputed KL SNPs from HapMap reference data of the Eastern population. The statistically significant KL SNPs including the imputed SNPs distributed evenly over the KL gene area. The results in this study suggest klotho is a major player in the development of T2DM and the KL SNPs found in the case could be a risk marker of T2DM in the cohort.

UBAP2 plays a role in bone homeostasis through the regulation of osteoblastogenesis and osteoclastogenesis

Osteoporosis is a condition characterized by decreased bone mineral density (BMD) and reduced bone strength, leading to an increased risk of fractures. Here, to identify novel risk variants for susceptibility to osteoporosis-related traits, an exome-wide association study is performed with 6,485 exonic single nucleotide polymorphisms (SNPs) in 2,666 women of two Korean study cohorts. The rs2781 SNP in UBAP2 gene is suggestively associated with osteoporosis and BMD with p-values of 6.1 × 10-7 (odds ratio = 1.72) and 1.1 × 10-7 in the case-control and quantitative analyzes, respectively. Knockdown of Ubap2 in mouse cells decreases osteoblastogenesis and increases osteoclastogenesis, and knockdown of ubap2 in zebrafish reveals abnormal bone formation. Ubap2 expression is associated with E-cadherin (Cdh1) and Fra1 (Fosl1) expression in the osteclastogenesis-induced monocytes. UBAP2 mRNA levels are significantly reduced in bone marrow, but increased in peripheral blood, from women with osteoporosis compared to controls. UBAP2 protein level is correlated with the blood plasma level of the representative osteoporosis biomarker osteocalcin. These results suggest that UBAP2 has a critical role in bone homeostasis through the regulation of bone remodeling.

Identification of Genetic Markers Linked to The Activity of Indoleamine 2,3-Dioxygenase and Kidney Function

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-degrading enzyme belonging to the kynurenine pathway. IDO activity has been suggested as a potential biomarker for early diagnosis of chronic kidney disease (CKD). The aim of this study was to perform coincident association analysis to gain genetic insights into the correlation between IDO activity and CKD. This study evaluated the association between IDO activity and CKD using the Korea Association REsource (KARE) cohort. Logistic and linear regression were used to analyze CKD and quantitative phenotypes such as IDO and estimated glomerular filtration rate (eGFR). Our results identified 10 single nucleotide polymorphisms (SNPs) that were coincidently associated with both IDO and CKD (p < 0.001). Among them, rs6550842, rs77624055, and rs35651150 were selected as potential candidates after excluding SNPs with insufficient evidence for having an association with IDO or CKD. Further expression quantitative trait loci (eQTL) analysis for variants at selected loci showed that rs6550842 and rs35651150 significantly affected the expression of NKIRAS1 and SH2D4A genes in human tissues, respectively. Additionally, we highlighted that the NKIRAS1 and BMP6 genes were correlated with IDO activity and CKD through signaling pathways associated with inflammation. Our data suggest that NKIRAS1, SH2D4A, and BMP6 were potential causative genes affecting IDO activity and CKD through integrated analysis. Identifying these genes could aid in early detection and treatment by predicting the risk of CKD associated with IDO activity.

Effect of genetic variants in UBE2O and TPK1 on facial morphology of Koreans

Human face is a highly heritable and complex trait. Many genome-wide analyses have identified genetic variants influencing facial morphology. Genome-wide association studies (GWAS) investigating facial morphologies of different populations provide a comprehensive insight into the genetic basis of the human face. Here, we report a GWAS of normal facial variation in Koreans using an array optimized for the Korean population (KoreanChip). We found that novel genetic variants encompassing four loci reached the genome-wide significance threshold. They include LOC107984547, UBE2O, TPK1 and LINC01148 loci associated with facial angle, brow ridge protrusion, nasal height, and eyelid curvature. Our results also validated previously published genetic loci, including FAT4, SOX9, and TBX3 loci. All confirmed genetic variants showed phenotypic differences involving each facial trait based on the effect of the minor allele. The present study highlights genetic signals associated with normal human facial variation and provides candidates for functional studies.

Genetic variants of FGFR family associated with height, hypertension, and osteoporosis

BACKGROUND

Hypertension and osteoporosis are the most common types of health problems. A recent study suggested that the fibroblast growth factor receptor-like protein 1 (FGFRL1) gene in giraffes is the most promising candidate gene that may have direct effects on both the skeleton and the cardiovascular system.

AIM

Our study purposed to replicate the finding that the FGFR5 gene is related to giraffe-related characteristics (height, hypertension, and osteoporosis), and to assess the associations between genetic variants of the FGFR family and three phenotypes.

SUBJECTS AND METHODS

An association study was performed to confirm the connections between hypertension, osteoporosis, and height and the FGFR family proteins (FGFR1 to FGFR5).

RESULTS

We identified a total of 192 genetic variants in the FGFR family and found six SNVs in the FGFR2, FGFR3, and FGFR4 genes that were associated with two phenotypes simultaneously. Also, the FGFR family was found to be involved in calcium signalling, and three genetic variants of the FGFR3 gene showed significant signals in the pituitary and hypothalamus.

CONCLUSION

Taken together, these findings suggest that FGFR genes are associated with hypertension, height, and osteoporosis. In particular, the present study highlights the FGFR3 gene, which influences two fundamental regulators of bone remodelling.

Effects of Loganin on Bone Formation and Resorption In Vitro and In Vivo

Osteoporosis is a disease caused by impaired bone remodeling that is especially prevalent in elderly and postmenopausal women. Although numerous chemical agents have been developed to prevent osteoporosis, arguments remain regarding their side effects. Here, we demonstrated the effects of loganin, a single bioactive compound isolated from Cornus officinalis, on osteoblast and osteoclast differentiation in vitro and on ovariectomy (OVX)-induced osteoporosis in mice in vivo. Loganin treatment increased the differentiation of mouse preosteoblast cells into osteoblasts and suppressed osteoclast differentiation in primary monocytes by regulating the mRNA expression levels of differentiation markers. Similar results were obtained in an osteoblast-osteoclast co-culture system, which showed that loganin enhanced alkaline phosphatase (ALP) activity and reduced TRAP activity. In in vivo experiments, the oral administration of loganin prevented the OVX-induced loss of bone mineral density (BMD) and microstructure in mice and improved bone parameters. In addition, loganin significantly increased the serum OPG/RANKL ratio and promoted osteogenic activity during bone remodeling. Our findings suggest that loganin could be used as an alternative treatment to protect against osteoporosis.

FGFRL1 and FGF genes are associated with height, hypertension, and osteoporosis

Hypertension and osteoporosis are two major disorders, which interact with each other. Specific genetic signals involving the fibroblast growth factor receptor-like 1 (FGFRL1) gene are related to high blood pressure and bone growth in giraffes. FGFRL1 is associated with cardiovascular system and bone formation. We performed an association study to investigate the role of FGFRL1 in hypertension, osteoporosis, and height determination in humans. In addition, we identified three kinds of phenotypes in fibroblast growth factor (FGF) genes and examined their association with the FGFRL1 gene. We identified 42 SNPs in the FGFRL1 gene associated with each trait. We then analyzed the potential functional annotation of each SNP. The FGFRL1 gene was found to be associated with height, hypertension, and osteoporosis, consistent with the results of a previous study. In addition, the FGF2, FGF4, FGF10, FGF18, and FGF22 genes were found to interact with the FGFRL1 gene. Our study suggests that both FGFRL1 and FGFRL1-related genes may determine the height and the prevalence of osteoporosis and hypertension in the Korean population.

Metabolite Genome-Wide Association Study for Indoleamine 2,3-Dioxygenase Activity Associated with Chronic Kidney Disease

Chronic kidney disease (CKD) causes progressive damage to kidney function with increased inflammation. This process contributes to complex amino acid changes. Indoleamine 2,3-dioxygenase (IDO) has been proposed as a new biomarker of CKD in previous studies. In our research, we performed a metabolite genome-wide association study (mGWAS) to identify common and rare variants associated with IDO activity in a Korean population. In addition, single-nucleotide polymorphisms (SNPs) selected through mGWAS were further analyzed for associations with the estimated glomerular filtration rate (eGFR) and CKD. A total of seven rare variants achieved the genome-wide significance threshold (p < 1 × 10-8). Among them, four genes (TNFRSF19, LOC105377444, LOC101928535, and FSTL5) associated with IDO activity showed statistically significant associations with eGFR and CKD. Most of these rare variants appeared specifically in an Asian geographic region. Furthermore, 15 common variants associated with IDO activity were detected in this study and five novel genes (RSU1, PDGFD, SNX25, LOC107984031, and UBASH3B) associated with CKD and eGFR were identified. This study discovered several loci for IDO activity via mGWAS and provided insight into the underlying mechanisms of CKD through association analysis with CKD. To the best of our knowledge, this is the first study to suggest a genetic link between IDO activity and CKD through comparative and integrated analysis.

Interaction between ALDH2 rs671 and life habits affects the risk of hypertension in Koreans: A STROBE observational study

Aldehyde dehydrogenase-2 (ALDH2) is associated with the risk of hypertension, and the effects of lifestyle factors on blood pressure vary according to genotype. Among the Han Chinese, the risk of hypertension is lower in the group with the rs671 A allele than in the group with the G allele, and there is a significant association between the frequency of fried food consumption and hypertension. However, the A allele significantly increases the risk of hypertension with increased fried food intake. This study aimed to investigate the effect of the relationship between ALDH2 polymorphism and complex lifestyle habits (fried food consumption and exercise) on hypertension.rs671 polymorphisms of ALDH2 were examined using Korean genome and epidemiology data from 8157 hypertensive cases and 9550 controls. Further, we investigated whether the A allele is protective against hypertension in Koreans and explored the effect of the combination of fried food intake and exercise habits on hypertension by genotype.The genotype frequencies of rs671, which is specific to East Asia, were 2.51% AA, 26.66% GA, and 70.83% GG in the Korean population. The group with inactive aldehyde dehydrogenase-2 had a low odds ratio [OR = 0.75 (95% CI:0.69-0.80), P = 4.35 × 10-14] of hypertension, and low metabolism of acetaldehyde. Subjects carrying the A allele exhibited an increased risk of hypertension with increased fried food intake without exercise [OR = 2.256 (95% CI:1.094-4.654), P = .028].ALDH2 polymorphism and complex lifestyle habits (fried food consumption and exercise) are associated with the risk of hypertension. Further, the A allele is associated with a low risk of hypertension, but it increases the risk of hypertension as fried food intake without exercise increases.

Association between MANBA Gene Variants and Chronic Kidney Disease in a Korean Population

Chronic kidney disease (CKD), a damaged condition of the kidneys, is a global public health problem that can be caused by diabetes, hypertension, and other disorders. Recently, the MANBA gene was identified in CKD by integrating CKD-related variants and kidney expression quantitative trait loci (eQTL) data. This study evaluated the effects of MANBA gene variants on CKD and kidney function-related traits using a Korean cohort. We also analyzed the association of MANBA gene variants with kidney-related traits such as the estimated glomerular filtration rate (eGFR), and blood urea nitrogen (BUN), creatinine, and uric acid levels using linear regression analysis. As a result, 14 single nucleotide polymorphisms (SNPs) were replicated in CKD (p < 0.05), consistent with previous studies. Among them, rs4496586, which was the most significant for CKD and kidney function-related traits, was associated with a decreased CKD risk in participants with the homozygous minor allele (CC), increased eGFR, and decreased creatinine and uric acid concentrations. Furthermore, the association analysis between the rs4496586 genotype and MANBA gene expression in human tubules and glomeruli showed high MANBA gene expression in the minor allele carriers. In conclusion, this study demonstrated that MANBA gene variants were associated with CKD and kidney function-related traits in a Korean cohort.

A Genome-Wide Association Study of Novel Genetic Variants Associated With Anthropometric Traits in Koreans

Most previous genome-wide association studies (GWAS) have identified genetic variants associated with anthropometric traits. However, most of the evidence were reported in European populations. Anthropometric traits such as height and body fat distribution are significantly affected by gender and genetic factors. Here we performed GWAS involving 64,193 Koreans to identify the genetic factors associated with anthropometric phenotypes including height, weight, body mass index, waist circumference, hip circumference, and waist-to-hip ratio. We found nine novel single-nucleotide polymorphisms (SNPs) and 59 independent genetic signals in genomic regions that were reported previously. Of the 19 SNPs reported previously, eight genetic variants at RP11-513I15.6 and one genetic variant at the RP11-977G19.10 region and six Asian-specific genetic variants were newly found. We compared our findings with those of previous studies in other populations. Five overlapping genetic regions (PAN2, ANKRD52, RNF41, HGMA1, and C6orf106) had been reported previously but none of the SNPs were independently identified in the current study. Seven of the nine newly found novel loci associated with height in women revealed a statistically significant skeletal expression of quantitative trait loci. Our study provides additional insight into the genetic effects of anthropometric phenotypes in East Asians.

MYLK and PTGS1 Genetic Variations Associated with Osteoporosis and Benign Breast Tumors in Korean Women

Osteoporosis, characterized by reduced bone mass and increased bone fragility, is a disease prevalent in women. Likewise, breast cancer is a multifactorial disease and considered the major cause of mortality in premenopausal and postmenopausal women worldwide. Our data demonstrated the association of the MYLK gene and PTGS1 gene variants with osteoporosis and benign breast tumor risk and the impact of ovariectomy on osteoporosis in Korean women. We performed a genome-wide association study (GWAS) of women with osteoporosis and benign breast tumors. There were 60 single nucleotide polymorphisms (SNPs) and 12 SNPs in the MYLK and PTGS1 genes, associated with benign breast tumors and osteoporosis. Our study showed that women with homozygous MYLK rs12163585 major alleles had an increased risk of osteoporosis following ovariectomy compared to those with minor alleles. Women carrying the minor PTGS1 rs1213265 allele and not treated via ovariectomy carried a higher risk of osteoporosis than those who underwent ovariectomy with a homozygous genotype at the major alleles. Our results suggest that both the MYLK and PTGS1 genes are genetic factors associated with the phenotypes, and these associations appear to be modulated by ovariectomy.

Association of MACROD2 gene variants with obesity and physical activity in a Korean population

Background

Obesity is a serious and common complex disease caused by the influence of genetic and environmental factors. Therefore, we aimed to evaluate the effect of genetic variants on obesity and the possibility of preventing obesity through physical activity using association analysis.

Methods

This study analyzed the association between obesity and variants in the MACROD2 gene in the Korean association resource (KARE) cohort using logistic regression analysis. Linear regression analysis was performed for obesity‐related phenotype traits including body mass index (BMI), body fat percentage (BFP), abdominal fat percentage (AbFP), and the waist‐to‐hip ratio (WHR). The level of physical activity was analyzed by dividing the participants into two groups according to the cutoff of one hour or more of daily intense activity.

Results

As a result, rs6079275 in the MACROD2 gene had the highest significance in obesity and phenotypic characteristics. Minor allele carriers (CC, CG) of rs6079275 decreased the obesity risk (OR = 0.57, 95% CI = 0.40–0.82, p = 2.34 × 10⁻³) and showed a tendency to decrease the risk of BMI (β = −0.312, p = 8.99 × 10⁻⁴), BFP (β = −0.482, p = 4.19 × 10⁻³) and AbFP (β = −0.0051, p = 5.96 × 10⁻⁴). In addition, the participants with the minor allele (C) of rs6079275 had a reduced obesity risk with high physical activity (OR = 0.23, 95% CI: 0.14–0.93, p = 0.036).

Conclusions

This study demonstrated that variants in the MACROD2 gene were correlated with obesity, phenotypic traits, and physical activity in the Korean population. Therefore, we suggest the possibility of preventing obesity by identifying this genetic variation and the interactive effect of lifestyle in Koreans.

Scopolin Attenuates Osteoporotic Bone Loss in Ovariectomized Mice

Bone remodeling is a renewal process regulated by bone synthesis (osteoblasts) and bone destruction (osteoclasts). A previous study demonstrated that Lycii radicis cortex (LRC) extract inhibited ovariectomized (OVX)-induced bone loss in mice. This study investigated the anti-osteoporotic effects of bioactive constituent(s) from the LRC extract. The effective compound(s) were screened, and a single compound, scopolin, which acts as a phytoalexin, was chosen as a candidate component. Scopolin treatment enhanced alkaline phosphatase activity and increased mineralized nodule formation in MC3T3-E1 pre-osteoblastic cells. However, osteoclast differentiation in primary-cultured monocytes was reduced by treatment with scopolin. Consistently, scopolin treatment increased osteoblast differentiation in the co-culture of monocytes (osteoclasts) and MC3T3-E1 (osteoblast) cells. Scopolin treatment prevented bone mineral density loss in OVX-induced osteoporotic mice. These results suggest that scopolin could be a therapeutic bioactive constituent for the treatment and prevention of osteoporosis.

Has-miR-17 increases the malignancy of gastric lymphoma by HSP60/TNFR2 pathway

The purpose of this study was to investigate the expression and mechanism of miR-17 in gastric lym-phoma. miR-17mimics, miR-17 inhibitors and negative controls were transfected into human gastric lymphoma cell line cyp6d. The proliferation, invasion and apoptosis of cyp6d cells were detected by CCK-8, Transwell and TUNEL methods, respectively. The expression and clinicopathological features of miR-17 in gastric lymphoma were analyzed by real-time quantitative PCR. The target gene of miR-17 was predicted by targetscan 7.2, and the expression of miR-17 related protein was detected by Western blot. The results showed that the expression of miR-17 in gastric lymphoma was significantly higher than that in normal tissues (P < 0.05), which was closely related to lymph node metastasis, tumor size and distant metastasis (P < 0.05). The high expression of miR-17 significantly promoted the proliferation and invasion of cyp6d cells and inhibited apoptosis (P < 0.05). The high expression of miR-17 can regu¬late the expression of HSP60 and TNFR2. It has been found that miR-17 can promote the development of gastric lymphoma by regulating HSP60/TNFR2 pathway, which is a potential molecular target for the diagnosis and treatment of gastric lymphoma.

Association between non-Caucasian-specific ASCC1 gene polymorphism and osteoporosis and obesity in Korean postmenopausal women

INTRODUCTION

Osteoporosis is a common disorder characterized by decreased bone mineral density (BMD). Interestingly, osteoporosis and obesity have several similar features, including a genetic predisposition and a common bone marrow stem cell. With aging, the composition of bone marrow shifts to adipocytes, osteoclast activity increases, and osteoblast function declines, resulting in osteoporosis.

MATERIALS AND METHODS

We performed a genome-wide association study (GWAS) analysis with osteoporosis and body mass index (BMI) and did identify an association in 349 and 384 SNPs by filtering with the significant p values (p < 0.001) of BMI and osteoporosis, respectively.

RESULTS

Only three of those SNPs were common (rs2326365, rs7097028, and rs11000205) between the SNPs significantly associated with BMI and/or osteoporosis in Korean Association REsource (KARE) females. Two of the three SNPs belonged to the ASCC1 gene and one to the FAM50B gene. We carried out a minor allele frequency (MAF) analysis of the rs7097028 and rs11000205 SNPs in the ASCC1 gene with a geographic genome variant browser. Both rs7097028 and rs11000205 in the ASCC1 gene were seen mostly in African and Southeast Asian populations.

CONCLUSIONS

Our results suggest that the ASCC1 gene is a significant genetic factor for determining the risk for both osteoporosis and obesity in KARE postmenopausal females.

The interaction between FTO rs9939609 and physical activity is associated with a 2-fold reduction in the risk of obesity in Korean population

OBJECTIVE

FTO (fat mass and obesity-associated) gene is a well-known genetic risk factor for obesity. We investigated whether physical activity modulates the effect of FTO rs9939609 on obesity in Korean population.

METHODS

The study analyzed the correlation between physical activity and obesity in 8840 individuals representing the Korea Association Resource (KARE). The association between obesity-related traits and single-nucleotide polymorphisms (SNPs) was assessed using linear regression models. Physical activity was defined as 3 hours or more of daily intense activity.

RESULTS

Participants carrying rs9939609 (AT+AA) genotypes showed higher BMI compared with those carrying the wild-type (TT) homozygote. The highest significant association was observed between obesity-related traits (ß = .334, P value = 1.76 × 10^-6 ). FTO rs9939609 (AT+AA) increased the risk of obesity (OR = 1.42, CI [1.13-1.79]), which was correlated with BMI correlations. However, active exercise by subjects carrying the same genotype reduced the risk of obesity by nearly 2-fold (OR = 0.62, CI [0.25-0.84]). In contrast, TT genotype was not statistically significant in reducing the risk of obesity in the active exercise group.

CONCLUSIONS

Our results support a previous finding correlating FTO and obesity-related traits and suggest that the interaction with genetic variation and physical activity is an important risk factor for obesity.

Tuberculosis risk is associated with genetic polymorphisms in the LRP2, CUBN, and VDR genes

BACKGROUND

Vitamin D (Vit. D) is used extensively during tuberculosis treatment. Low levels of serum Vit. D increase the risk of active tuberculosis development. Altered expression of the proteins involved in Vit. D metabolism impairs cathelicidin production, thereby increasing the host susceptibility to tuberculosis.

OBJECTIVE

We are trying to investigate whether single nucleotide polymorphisms (SNPs) in LRP2, CUBN, and VDR genes could affect tuberculosis development.

METHODS

We included participants of the Korean Association Resource (KARE), part of the Korean Genome and Epidemiology Study (KoGES), and used their recorded data. A total of 8840 people (4182 men and 4658 women) were eligible subjects. The 5-kb regions from the ends of transcripts of GC, LRP2, CUBN, and VDR genes were amplified to select 13, 47, 70, and 15 SNPs, respectively. For association analysis and statistical analysis, PLINK version 1.07 and PASW Statistics version 18.0 were used.

RESULTS

Significant correlation was observed in 11, 2, and 1 SNPs in LRP2, CUBN, and VDR genes. The effect of rs6747692 of LRP2 on transcription factor binding was confirmed using RegulomeDB. We confirmed that rs2239182 of VDR is located in the genomic eQTL region and can affect transcription factor binding and gene expression.

CONCLUSIONS

Genetic polymorphisms in genes encoding proteins involved in Vit. D metabolism influence immune system components. Therefore, such polymorphisms may influence the susceptibility to Mycobacterium tuberculosis invasion and alter the defense mechanisms against Mycobacterium tuberculosis infection. The correlation between genetic variation and tuberculosis development can provide new guidelines for the management of tuberculosis.

Dietary Protein and Fat Intake Affects Diabetes Risk with CDKAL1 Genetic Variants in Korean Adults

Cyclin-dependent kinase 5 regulatory subunit-associated protein 1-like 1 (CDKAL1) is one of the strongest diabetes loci identified to date; evidence suggests that it plays an important role in insulin secretion. Dietary factors that affect insulin demand might enhance the risk of diabetes associated with CDKAL1 variants. Our aim was to examine the interactions between dietary protein and fat intake and CDKAL1 genetic variants in relation to the risk of diabetes in Korean adults. Single nucleotide polymorphisms (SNPs) were selected with a genome-wide association study (GWAS) for diabetes after adjustment for age, gender, and examination site. Using data from the Health Examinees (HEXA) Study of the Korean Genome and Epidemiology Study (KoGES), 3988 middle-aged Korean adults between 40–76 years of age (2034 men and 1954 women) were included in the study. Finally, rs7756992 located within the CDKAL1 gene region was selected from GWAS (p-value < 5 × 10⁻⁸). Multivariable logistic regression models were used to evaluate the interactions between genotypes and dietary protein and fat intake in relation to diabetes risk after adjustment for age, gender, BMI, waist circumference, physical activity, smoking status, drinking habits, and examination site. Significant interactions between CDKAL1 rs7756992 and dietary protein and fat intake for the risk of diabetes were observed in men (p-value < 0.05). In women, significant interactions between dietary protein and fat intake and CDKAL1 variants (rs7756992) were associated with increased risk of diabetes (p-value < 0.05). Dietary protein and fat intake interacted differently with CDKAL1 variants in relation to the risk of diabetes in Korean adults of both genders. These findings indicate that CDKAL1 variants play a significant role in diabetes and that dietary protein and fat intake could affect these associations.

Identifying Interactions between Dietary Sodium, Potassium, Sodium-Potassium Ratios, and FGF5 rs16998073 Variants and Their Associated Risk for Hypertension in Korean Adults

Hypertension is affected by both genetic and dietary factors. This study aimed to examine the interaction between dietary sodium/potassium intake, sodium–potassium ratios, and FGF5 rs16998073 and link these with increased risk for developing hypertension. Using data from the Health Examinee (HEXA) Study of the Korean Genome and Epidemiologic Study (KoGES), we were able to identify a total of 17,736 middle-aged Korean adults who could be included in our genome-wide association study (GWAS) to confirm any associations between hypertension and the FGF5 rs16998073 variant. GWAS analysis revealed that the FGF5 rs16698073 variant demonstrated the strongest association with hypertension in this population. Multivariable logistic regression was used to examine the relationship between dietary intake of sodium, potassium, and sodium–potassium ratios and the FGF5 rs16998073 genotypes (AA, AT, TT) and any increased risk of hypertension. Carriers with at least one minor T allele for FGF5 rs16998073 were shown to be at significantly higher risk for developing hypertension. Male TT carriers with a daily sodium intake ≥2000 mg also demonstrated an increased risk for developing hypertension compared to the male AA carriers with daily sodium intake <2000 mg (adjusted odds ratio (AOR) = 2.41, 95% confidence intervals (CIs) = 1.84–3.15, p-interaction < 0.0001). Female AA carriers with a daily potassium intake ≥3500 mg showed a reduced risk for hypertension when compared to female AA carriers with a daily potassium intake <3500 mg (AOR = 0.75. 95% CIs = 0.58–0.95, p-interaction < 0.0001). Male TT carriers in the mid-tertile for sodium–potassium ratio values showed the highest odds ratio for hypertension when compared to male AA carriers in the lowest-tertile for sodium–potassium ratio values (AOR = 3.03, 95% CIs = 2.14–4.29, p-interaction < 0.0001). This study confirmed that FGF5 rs16998073 variants do place their carriers (men and women) at increased risk for developing hypertension. In addition, we showed that high daily intake of sodium exerted a synergistic effect for hypertension when combined with FGF5 rs16998073 variants in both genders and that dietary sodium, potassium, and sodium–potassium ratios all interact with FGF5 rs16998073 and alter the risk of developing hypertension in carriers of either gender among Koreans.

Recapitulation of the Genetic Association of PLXNA2 with Bone Density and Osteoporosis via In Vitro Experiments Using a Korean Female Cohort

Osteoporosis is a bone disorder in which the imbalance of osteoclasts and osteoblasts leads to bone-destructive diseases especially among elderly women. Several factors, including genetic and environmental factors, contribute to the pathogenesis of these diseases. Bone mineral density (BMD) is a robust factor that influences osteoporosis; the development of osteoporosis in the elderly is estimated based on the BMD. Our previous microarray assay using murine preosteoblast cells revealed that Plexin A2 is associated with the differentiation and mineralization of bone-forming osteoblasts via bone morphogenetic protein 2 signaling. For our in vitro replication study using a Korean female cohort, we analyzed the genetic variation of PLEXIN A2 (PLXNA2) and its paralog genes (PLXNA1, A3, and A4) based on 125 single nucleotide polymorphisms (SNPs) associated with bone density and osteoporosis. In this study, the PLXNA2 gene was confirmed as a robust candidate gene associated with osteoporosis in Korean women. We have demonstrated that the SNPs rs4844649 (p = 9.3×10−3) and rs3748737 (p = 2.7×10−3) of PLXNA2 were the most significantly associated with bone density and osteoporosis, respectively. Consequently, this study demonstrates that the PLXNA2 gene is implicated in bone metabolism, further supporting the genetic association between polymorphisms in PLXNA2 and osteoporosis. Our current findings also suggest that polymorphisms in PLXNA2 may serve as feasible clinical targets for osteoporosis treatment in the future.

Anti-Osteoporotic Effects of Kukoamine B Isolated from Lycii Radicis Cortex Extract on Osteoblast and Osteoclast Cells and Ovariectomized Osteoporosis Model Mice

Osteoporosis is an abnormal bone remodeling condition characterized by decreased bone density, which leads to high risks of fracture. Previous study has demonstrated that Lycii Radicis Cortex (LRC) extract inhibits bone loss in ovariectomized (OVX) mice by enhancing osteoblast differentiation. A bioactive compound, kukoamine B (KB), was identified from fractionation of an LRC extract as a candidate component responsible for an anti-osteoporotic effect. This study investigated the anti-osteoporotic effects of KB using in vitro and in vivo osteoporosis models. KB treatment significantly increased the osteoblastic differentiation and mineralized nodule formation of osteoblastic MC3T3-E1 cells, while it significantly decreased the osteoclast differentiation of primary-cultured monocytes derived from mouse bone marrow. The effects of KB on osteoblastic and osteoclastic differentiations under more physiological conditions were also examined. In the co-culture of MC3T3-E1 cells and monocytes, KB promoted osteoblast differentiation but did not affect osteoclast differentiation. In vivo experiments revealed that KB significantly inhibited OVX-induced bone mineral density loss and restored the impaired bone structural properties in osteoporosis model mice. These results suggest that KB may be a potential therapeutic candidate for the treatment of osteoporosis.

A novel missense mutation in the ACTG1 gene in a family with congenital autosomal dominant deafness: A case report

The ACTG1 gene encodes the cytoskeletal protein γ-actin, which functions in non-muscle cells and is abundant in the auditory hair cells of the cochlea. Autosomal dominant missense mutations in ACTG1 are associated with DFNA20/26, a disorder that is typically characterized by post-lingual progressive hearing loss. To date, 17 missense mutations in ACTG1 have been reported in 20 families with DFNA20/26. The present study described a small family with autosomal dominant nonsyndromic hearing loss. A novel heterozygous missense mutation, c.94C>T (p.Pro32Ser), in ACTG1 was identified using the TruSight One sequencing panel. Notably, congenital hearing loss in our proband was identified by newborn hearing screening at birth. In silico predictions of protein structure and function indicate that the p.Pro32Ser mutation may result in conformational changes in γ-actin. The present study expands the understanding of the phenotypic effects of heterozygous missense mutations in the ACTG1 gene. In specific, the present results emphasize that mutations in ACTG1 result in a diverse spectrum of onset ages, including congenital in addition to post-lingual onset.

Transcriptional profiling of human femoral mesenchymal stem cells in osteoporosis and its association with adipogenesis

Genetic alterations are major contributing factors in the development of osteoporosis. Osteoblasts and adipocytes share a common origin, mesenchymal stem cells (MSCs), and their genetic determinants might be important in the relationship between osteoporosis and obesity. In the present study, we aimed to isolate differentially expressed genes (DEGs) in osteoporosis and normal controls using human MSCs, and elucidate the common pathways and genes related to osteoporosis and adipogenesis. Human MSCs were obtained from the bone marrow of femurs from postmenopausal women during orthopedic surgeries. RNA sequencing (RNA-seq) was carried out using next-generation sequencing (NGS) technology. DEGs were identified using RNA-seq data. Ingenuity pathway analysis (IPA) was used to elucidate the common pathway related to osteoporosis and adipogenesis. Candidate genes for the common pathway were validated with other independent osteoporosis and obese subjects using RT-PCR (reverse transcription-polymerase chain reaction) analysis. Fifty-three DEGs were identified between postmenopausal osteoporosis patients and normal bone mineral density (BMD) controls. Most of the genetic changes were related to the differentiation of cells. The nuclear receptor subfamily 4 group A (NR4A) family was identified as possible common genes related to osteogenesis and adipogenesis. The expression level of the mRNA of NR4A1 was significantly higher in osteoporosis patients than in controls (p=0.018). The expression level of the mRNA of NR4A2 was significantly higher in obese patients than in controls (p=0.041). Some genetic changes in MSCs are involved in the pathophysiology of osteoporosis. The NR4A family might comprise common genes related to osteoporosis and obesity.

Correction: Identification of a Novel Mutation in BRD4 that Causes Autosomal Dominant Syndromic Congenital Cataracts Associated with Other Neuro-Skeletal Anomalies

[This corrects the article DOI: 10.1371/journal.pone.0169226.].

Identification of a Novel Mutation in BRD4 that Causes Autosomal Dominant Syndromic Congenital Cataracts Associated with Other Neuro-Skeletal Anomalies

Congenital cataracts can occur as a non-syndromic isolated ocular disease or as a part of genetic syndromes accompanied by a multi-systemic disease. Approximately 50% of all congenital cataract cases have a heterogeneous genetic basis. Here, we describe three generations of a family with an autosomal dominant inheritance pattern and common complex phenotypes, including bilateral congenital cataracts, short stature, macrocephaly, and minor skeletal anomalies. We did not find any chromosomal aberrations or gene copy number abnormalities using conventional genetic tests; accordingly, we conducted whole-exome sequencing (WES) to identify disease-causing genetic alterations in this family. Based on family WES data, we identified a novel BRD4 missense mutation as a candidate causal variant and performed cell-based experiments by ablation of endogenous BRD4 expression in human lens epithelial cells. The protein expression levels of connexin 43, p62, LC3BII, and p53 differed significantly between control cells and cells in which endogenous BRD4 expression was inhibited. We inferred that a BRD4 missense mutation was the likely disease-causing mutation in this family. Our findings may improve the molecular diagnosis of congenital cataracts and support the use of WES to clarify the genetic basis of complex diseases.

Effects of Dihydrophaseic Acid 3'-O-β-d-Glucopyranoside Isolated from Lycii radicis Cortex on Osteoblast Differentiation

Our previous study showed that ethanol extract of Lyciiradicis cortex (LRC) prevented the loss of bone mineral density in ovariectomized mice by promoting the differentiation of osteoblast linage cells. Here, we performed fractionation and isolation of the bioactive compound(s) responsible for the bone formation–enhancing effect of LRC extract. A known sesquiterpene glucoside, (1′R,3′S,5′R,8′S,2Z,4E)-dihydrophaseic acid 3′-O-β-d-glucopyranoside (abbreviated as DPA3G), was isolated from LRC extract and identified as a candidate constituent. We investigated the effects of DPA3G on osteoblast and osteoclast differentiation, which play fundamental roles in bone formation and bone resorption, respectively, during bone remodeling. The DPA3G fraction treatment in mesenchymal stem cell line C3H10T1/2 and preosteoblast cell line MC3T3-E1 significantly enhanced cell proliferation and alkaline phosphatase activity in both cell lines compared to the untreated control cells. Furthermore, DPA3G significantly increased mineralized nodule formation and the mRNA expression of osteoblastogenesis markers, Alpl, Runx2, and Bglap, in MC3T3-E1 cells. The DPA3G treatment, however, did not influence osteoclast differentiation in primary-cultured monocytes of mouse bone marrow. Because osteoblastic and osteoclastic precursor cells coexist in vivo, we tested the DPA3G effects under the co-culture condition of MC3T3-E1 cells and monocytes. Remarkably, DPA3G enhanced not only osteoblast differentiation of MC3T3-El cells but also osteoclast differentiation of monocytes, indicating that DPA3G plays a role in the maintenance of the normal bone remodeling balance. Our results suggest that DPA3G may be a good candidate for the treatment of osteoporosis.

Association of the I264T variant in the sulfide quinone reductase-like (SQRDL) gene with osteoporosis in Korean postmenopausal women

To identify novel susceptibility variants for osteoporosis in Korean postmenopausal women, we performed a genome-wide association analysis of 1180 nonsynonymous single nucleotide polymorphisms (nsSNPs) in 405 individuals with osteoporosis and 722 normal controls of the Korean Association Resource cohort. A logistic regression analysis revealed 72 nsSNPs that showed a significant association with osteoporosis (p<0.05). The top 10 nsSNPs showing the lowest p-values (p = 5.2×10-4-8.5×10-3) were further studied to investigate their effects at the protein level. Based on the results of an in silico prediction of the protein's functional effect based on amino acid alterations and a sequence conservation evaluation of the amino acid residues at the positions of the nsSNPs among orthologues, we selected one nsSNP in the SQRDL gene (rs1044032, SQRDL I264T) as a meaningful genetic variant associated with postmenopausal osteoporosis. To assess whether the SQRDL I264T variant played a functional role in the pathogenesis of osteoporosis, we examined the in vitro effect of the nsSNP on bone remodeling. Overexpression of the SQRDL I264T variant in the preosteoblast MC3T3-E1 cells significantly increased alkaline phosphatase activity, mineralization, and the mRNA expression of osteoblastogenesis markers, Runx2, Sp7, and Bglap genes, whereas the SQRDL wild type had no effect or a negative effect on osteoblast differentiation. Overexpression of the SQRDL I264T variant did not affect osteoclast differentiation of the primary-cultured monocytes. The known effects of hydrogen sulfide (H2S) on bone remodeling may explain the findings of the current study, which demonstrated the functional role of the H2S-catalyzing enzyme SQRDL I264T variant in osteoblast differentiation. In conclusion, the results of the statistical and experimental analyses indicate that the SQRDL I264T nsSNP may be a significant susceptibility variant for osteoporosis in Korean postmenopausal women that is involved in osteoblast differentiation.

Identification of KMT2D and KDM6A mutations by exome sequencing in Korean patients with Kabuki syndrome

Kabuki syndrome (KS) (OMIM#147920) is a multiple congenital anomaly/mental retardation syndrome. Recently, pathogenic variants in KMT2D and KDM6A were identified as the causes of KS in 55.8-80.0% of patients. To elucidate further the molecular characteristics of Korean patients with KS, we screened a cohort of patients with clinically defined KS for mutations in KMT2D and KDM6A. Whole-exome sequencing and direct sequencing for validation were performed in 12 patients with a clinical suspicion of KS. KMT2D and KDM6A mutations were identified in 11 (91.7%) patients. No recurrent mutation was observed, and 10 out of the 11 mutations found were novel. KMT2D mutations were detected in 10 patients, including four small deletions or insertions and four nonsense and two missense mutations. One girl had a novel splice-site mutation in KDM6A. Each patient had a unique individual mutation. This is the first report of mutational analysis via exome sequencing in Korean patients with KS. Because the mutation-detection rate was high in this study, rigorous mutation analysis of KMT2D and KDM6A may be an important tool for the early diagnosis and genetic counseling of Korean patients with KS.

The PARK2 gene is involved in the maintenance of pancreatic β-cell functions related to insulin production and secretion

Several association studies have implicated the PARK2 gene that encodes parkin--the key molecule orchestrating the mitochondrial quality control system--as a candidate susceptibility gene for diabetes. A total of 7551 unrelated Korean KARE cohort subjects were analyzed to investigate the association between the PARK2 single nucleotide polymorphism (SNP) and quantitative glycemic traits. Two SNPs, rs10455889 and rs9365294, were significantly associated with fasting plasma glucose level (p=∼1.2×10(-4)) and insulin secretion indices (p=∼7.4×10(-5)) in male KARE subjects. Parkin was expressed predominantly in the rat pancreatic islets. Downregulation of the Park2 gene in rat INS-1 β-cells resulted in a significant decrease in the glucose-stimulated insulin secretion, intracellular insulin gene expression, and intracellular ATP level. The Park2-depleted β-cells also exhibited increased mitochondrial fragmentation and ROS production and decreased mitochondrial membrane potential. Both population-based statistical evaluation and experimental evidence demonstrated a fundamental role of the PARK2 gene in the maintenance of β-cell function.

Genetic and clinical characteristics of korean patients with isolated hypoparathyroidism: from the Korean hypopara registry study

Isolated hypoparathyroidism (IH) shows heterogeneous phenotypes and can be caused by defects in a variety of genes. The goal of our study was to determine the clinical features and to analyze gene mutations in a large cohort of Korean patients with sporadic or familial IH. We recruited 23 patients. They showed a broad range of onset age and various values of biochemical data. Whole exome sequencing was performed on two affected cases and one unaffected individual in a family. All coding exons and exon-intron borders of GCMB, CASR, and prepro-PTH were sequenced using PCR-amplified DNA. In one family who underwent the whole exome sequencing analysis, approximately 300 single nucleotide changes emerged as candidates for genetic alteration. Among them, we identified a functional mutation in exon 2 of GCMB (C106R) in two affected cases. Besides, heterozygous gain-of-function mutations in the CASR gene were found in other subjects; D410E and P221L. We also found one single nucleotide polymorphism (SNP) in the prepro-PTH gene, five SNPs in the CASR gene, and four SNPs in the GCMB gene. The current study represents a variety of biochemical phenotypes in IH patients with the molecular genetic diagnosis of IH.

Genome-wide association study of serum albumin:globulin ratio in Korean populations

Low albumin:globulin (A/G) ratios are associated with vascular adverse events, nephrotic syndrome and autoimmune disease. Genome-wide association studies (GWASs) have been identifying genetic variants associated with total serum protein, serum albumin and globulins, but A/G ratio has never been considered the target phenotype. To identify the genetic basis of the A/G ratio, we performed a GWAS on A/G ratio in 4205 individuals from the Ansan cohort and confirmed the results in 4637 subjects from the Ansung cohort. The single-nucleotide polymorphism (SNP) genotypes of Affymetrix SNP array 5.0 were obtained from the Korean Association Resource Consortium, and we selected 290 659 common SNPs with a minor allele frequency >0.05. Genetic factors for A/G ratio were analyzed by linear regression analysis, controlling for age, sex, body mass index, smoking status and alcohol drinking status as covariates. From the GWAS of the Ansan cohort, we identified two significant genome-wide signals (P-values<5 × 10(-8)) and 36 moderate signals (P-value<1.0 × 10(-4)). These 38 signals were tested in the Ansung population. Eleven SNPs from six loci (GALNT2, IRF4, HLA-DBP1, SLC31A1, FADS1 and TNFRSF13B) were replicated, with P-values<0.05. The most compelling association was observed in the TNFRSF13B locus on chromosome 17p11.2 (SNP: rs4561508), with an overall combined P-value=7.80 × 10(-24). The other significant signal was observed on chromosome 11q12.2-the FADS1 locus (SNP: rs174548)-with an overall combined P-value=3.54 × 10(-8).

Association between the SPRY1 gene polymorphism and obesity-related traits and osteoporosis in Korean women

BACKGROUND

Emerging evidence has revealed a close relationship between obesity and osteoporosis. It was reported recently that conditional knockout of the Spry1 gene in mice adipocytes causes an increase in body fat and a decrease in bone mass, and that these phenotypes are rescued by Spry1 overexpression in adipose tissue. In this study, we investigated whether genetic variation in the human SPRY1 gene is associated with obesity-related phenotypes and/or osteoporosis in humans.

METHODS

We performed a candidate gene association analysis between the four single nucleotide polymorphisms (SNPs) and 14 imputed SNPs in the SPRY1 gene and obesity-related traits and osteoporosis in a Korean women cohort (3013 subjects).

RESULTS

All four SPRY1 gene SNPs were significantly associated with either obesity-related traits or osteoporosis. The TGCC haplotype in the SRPY1 gene showed simultaneous association with an increased risk for obesity-related traits, percentage body fat (p=0.0087) and percentage abdominal fat (p=0.047), and osteoporosis (odds ratio=1.50; p=0.025) in the recessive genetic model.

CONCLUSIONS

Our results support a previous finding in conditional Spry1 gene knockout mice and suggest that the SPRY1 gene is an important genetic factor for determining the risk of both obesity and osteoporosis in humans.

Association analysis of reactive oxygen species-hypertension genes discovered by literature mining

Oxidative stress, which results in an excessive product of reactive oxygen species (ROS), is one of the fundamental mechanisms of the development of hypertension. In the vascular system, ROS have physical and pathophysiological roles in vascular remodeling and endothelial dysfunction. In this study, ROS-hypertension-related genes were collected by the biological literature-mining tools, such as SciMiner and gene2pubmed, in order to identify the genes that would cause hypertension through ROS. Further, single nucleotide polymorphisms (SNPs) located within these gene regions were examined statistically for their association with hypertension in 6,419 Korean individuals, and pathway enrichment analysis using the associated genes was performed. The 2,945 SNPs of 237 ROS-hypertension genes were analyzed, and 68 genes were significantly associated with hypertension (p < 0.05). The most significant SNP was rs2889611 within MAPK8 (p = 2.70 × 10(-5); odds ratio, 0.82; confidence interval, 0.75 to 0.90). This study demonstrates that a text mining approach combined with association analysis may be useful to identify the candidate genes that cause hypertension through ROS or oxidative stress.

NF1 deficiency causes Bcl-xL upregulation in Schwann cells derived from neurofibromatosis type 1-associated malignant peripheral nerve sheath tumors

Since the bi-allelic inactivation of both neurofibromin 1 (NF1) gene alleles (NF1(-/-)) in Schwann cells (SCs) is common in both benign plexiform neurofibromas (PNs) and malignant peripheral nerve sheath tumors (MPNSTs) in patients with neurofibromatosis type 1 (NF1), other genetic alterations in SCs may be required for tumor progression of PNs to MPNSTs. We found that the anti-apoptotic Bcl-xL protein is upregulated in MPNST tissues compared to PN tissues from patients with NF1 by immunohistological staining. In addition, we investigated whether Bcl-xL is upregulated in SCs derived from MPNSTs and found a significantly higher Bcl-xL expression level in sNF96.2 MPNST-derived SCs compared to normal human SCs (HSCs). We also discovered that the increased Bcl-xL expression caused an increase in drug resistance to doxorubicin in MPNST-derived SCs. Manipulation of NF1 gene expression levels by treatment with small interfering RNA (siRNA) and overexpression of the neurofibromin GAP-related domain (NF1-GRD) demonstrated that upregulated Bcl-xL expression in MPNST-derived SCs was caused by NF1 deficiency. Treatment with the Erk1/2 inhibitor, PD98059, resulted in a slight increase in Bcl-xL levels in neurofibromin-depleted normal HSCs, indicating that Bcl-xL upregulation in MPNST-derived SCs is mediated by activated Erk1/2, which is a Ras downstream protein regulated by neurofibromin. As the reduction of Bcl-xL expression restored sensitivity to doxorubicin-induced apoptosis in sNF96.2 cells, we examined the effect of the small molecule Bcl-xL inhibitor ABT-737 on sNF96.2 cells. A very low dose of ABT-737 combined with doxorubicin synergistically enhanced sensitivity to doxorubicin-induced apoptosis in sNF96.2 cells, suggesting that ABT-737 and doxorubicin may be a good combination to effectively treat NF1-associated MPNSTs with minimal side-effects. Collectively, our results suggest that upregulation of Bcl-xL in MPNST-derived SCs may be caused by the NF1 deficiency-mediated elevation in Ras/MAPK signaling and may provide a new potential chemotherapeutic target in patients with NF1 and MPNSTs.

Clinical and genetic spectrum of 18 unrelated Korean patients with Sotos syndrome: frequent 5q35 microdeletion and identification of four novel NSD1 mutations

Sotos syndrome is an overgrowth syndrome with characteristic facial dysmorphism, variable severity of learning disabilities and macrocephaly with overgrowth. Haploinsufficiency of the nuclear receptor SET domain-containing protein 1 (NSD1) gene located on 5q35 has been implicated as the cause of Sotos syndrome. This study was performed to investigate the mutation spectrum of NSD1 abnormalities and meaningful genotype-phenotype correlations in Korean patients with Sotos syndrome. Eighteen unrelated Korean patients with Sotos syndrome were enrolled for clinical and molecular analyses. Cytogenetic studies were performed to confirm 5q35 microdeletion, and NSD1 sequencing analysis was performed to identify intragenic mutations. NSD1 abnormalities were identified in 15 (83%) patients. Among them, eight patients (53%) had 5q35 microdeletions and the other seven patients (47%) had seven different NSD1 intragenic mutations including four novel mutations. The mutation spectrum of Korean patients with Sotos syndrome was similar to that of previous studies for Japanese patients. Height was significantly shorter and age of walking alone was significantly older in the microdeletion group compared with those in the intragenic mutation group. No significant differences were observed for other clinical characteristics between the microdeletion and intragenic mutation groups. Further studies with a larger number of patients will be necessary to draw conclusive genotype-phenotype correlations.

Age-dependent association of the polymorphisms in the mitochondria-shaping gene, OPA1, with blood pressure and hypertension in Korean population

BACKGROUND

Essential hypertension is associated with mitochondrial dysfunction. Because mitochondrial dynamics; mitochondrial morphological changes are closely linked with various mitochondrial functions, we aimed to examine whether the genetic variation of the mitochondria-shaping genes influenced the susceptibility to blood pressure (BP) and hypertension.

METHODS

The quantitative BP trait analysis and hypertension case-control analysis for the total 52 single-nucleotide polymorphisms (SNPs) in the five major mitochondria-shaping genes were performed in the Korean Association Resource (KARE) study cohort (8,512 subjects).

RESULTS

In the total subjects of the KARE study cohort, there were no statistically significant associations of the SNPs in the five mitochondria-shaping genes with BP or hypertension after adjusting for multiple tests. However, the age group analysis in the 40s, 50s, and 60s age subgroups revealed that 15 SNPs out of 26 SNPs genotyped in the OPA1 gene were significantly associated with BP and/or hypertension in the 60s age subgroup and their association P values satisfied the Bonferroni-corrected significance level (P < 0.00625). Noticeably, nine SNPs were consistently associated with all the three traits; systolic BP (SBP), diastolic BP (DBP), and hypertension. In silico lookup of the associated SNPs in the Southern German population did not reveal associations with BP traits.

CONCLUSIONS

Our results indicate that genetic variation of the mitochondrial fusion-regulating gene, OPA1, might be associated with BP and hypertension in an age-dependent and population-specific manner in the Korean study cohort, and suggest that altered mitochondrial dynamics, especially involved in the mitochondrial fusion event, may play an important role in the pathogenesis of hypertension.