👤 Kenji Matsuzawa

Crohn's disease (CD) is a chronic inflammatory bowel disease with unknown etiology. Inflammatory chemical mediators synthesized from arachidonic acid, an n-6 polyunsaturated fatty acid (PUFA), have been shown to activate CD. Additionally, n-3 PUFAs are metabolized by the same enzyme as n-6 PUFAs and known to inhibit the arachidonic acid cascade. Our previous study noted that the presence of erythrocyte membrane fatty acids is a characteristic finding in Japanese CD patients. It was thus speculated that To investigate the relationship of Using previously reported findings regarding The presence of the rs174538 mutation in The rs174538 mutation alters the fatty acid profile through strong linkage to the Show less

A 50-year-old man with a triglyceride (TG) level of 11,397 mg/dL was admitted to our hospital. He consumed a high-fat and high-carbohydrate diet as well as more than 100 g of alcohol per day. He had type 2 diabetes and obesity and had previously suffered from severe acute pancreatitis twice. A genetic analysis revealed compound heterozygous mutations in APOA5 (c.56C>G and c.553G>T). In addition to low-fat meals and alcohol cessation, administration of pemafibrate lowered his triglyceride levels to <150 mg/dL. Show less

Epithelial cells are inherently contractile and in homeostasis, tissue integrity is maintained by balancing the uneven contractile forces in neighboring cells at the cell-cell interface. By contrast, epithelial cells can utilize an imbalance in contractile force to communicate various information to induce tissue-wide response as in wound healing. Contractility is generated and processed at the apical junctional complex (AJC) by the dynamic behavior of the actin cytoskeleton. Calcium signaling can pattern cellular responses based on its reach and amplitude and the actin cytoskeleton is supported by its wide ranging effects on actin regulators. Calcium transients regulate various cell behaviors associated with actin remodeling, such as in damage response and developmental morphogenesis. Here, we report that calcium maintains an adaptive pool of AJC-associated actin that is sensitive to tension and encoded by calcium dynamics. For this, the recently identified epithelial polarity module Homer-MUPP1/PatJ is required. Homer regulates calcium signaling in various tissue contexts through interaction with numerous components of the endoplasmic reticulum (ER) and plasma membrane (PM) calcium signal toolkit. Knockout of either Homer or MUPP1/PatJ attenuated tension-induced calcium response and severely disrupted wound healing migration, which is dependent on guidance input through AJC tension. We also show that Homer is integral to early embryonic neurodevelopment as its suppression causes failure of neural tube closure. Our findings highlight the critical role of localized calcium dynamics on AJC actin remodeling and cellular behavior, elucidating the means of tissue coordination through intercellular tension. Show less

Heparan sulfate (HS), a highly sulfated linear polysaccharide, is involved in diverse biological functions in various tissues. Although previous studies have suggested a possible contribution of HS to the differentiation of white adipocytes, there has been no direct evidence supporting this. Here, we inhibited the synthesis of HS chains in 3T3-L1 cells using CRISPR-Cas9 technology, resulting in impaired differentiation of adipocytes with attenuated bone morphogenetic protein 4 (BMP4)-fibroblast growth factor 1 (FGF1) signaling pathways. HS reduction resulted in reduced glucose uptake and decreased insulin-dependent intracellular signaling. We then made heterozygous mutant mice for the Ext1 gene, which encodes an enzyme essential for the HS biosynthesis, specifically in the visceral white adipose tissue (Fabp4-Cre Show less

Monogenic diabetes is clinically heterogeneous and differs from common forms of diabetes (type 1 and 2). We aimed to investigate the clinical usefulness of a comprehensive genetic testing system, comprised of targeted next-generation sequencing (NGS) with phenotype-driven bioinformatics analysis in patients with monogenic diabetes, which uses patient genotypic and phenotypic data to prioritize potentially causal variants. We performed targeted NGS of 383 genes associated with monogenic diabetes or common forms of diabetes in 13 Japanese patients with suspected (n = 10) or previously diagnosed (n = 3) monogenic diabetes or severe insulin resistance. We performed in silico structural analysis and phenotype-driven bioinformatics analysis of candidate variants from NGS data. Among the patients suspected having monogenic diabetes or insulin resistance, we diagnosed 3 patients as subtypes of monogenic diabetes due to disease-associated variants of INSR, LMNA, and HNF1B. Additionally, in 3 other patients, we detected rare variants with potential phenotypic effects. Notably, we identified a novel missense variant in TBC1D4 and an MC4R variant, which together may cause a mixed phenotype of severe insulin resistance. This comprehensive approach could assist in the early diagnosis of patients with monogenic diabetes and facilitate the provision of tailored therapy. Show less

Heparan sulfate (HS) is a sulfated linear polysaccharide on cell surfaces that plays an important role in physiological processes. HS is present in skeletal muscles but its detailed role in this tissue remains unclear. We examined the role of HS in the differentiation of C2C12 cells, a mouse myoblast cell line. We also phenotyped the impact of HS deletion in mouse skeletal muscles on their functions by using Cre-loxP system. CRISPR-Cas9-dependent HS deletion or pharmacological removal of HS dramatically impaired myoblast differentiation of C2C12 cells. To confirm the importance of HS in vivo, we deleted Ext1, which encodes an enzyme essential for HS biosynthesis, specifically in the mouse skeletal muscles (referred to as mExt1CKO mice). Treadmill and wire hang tests demonstrated that mExt1CKO mice exhibited muscle weakness. The contraction of isolated soleus muscles from mExt1CKO mice was also impaired. Morphological examination of mExt1CKO muscle tissue under light and electron microscopes revealed smaller cross sectional areas and thinner myofibrils. Finally, a model of muscle regeneration following BaCl These results demonstrate that HS plays an important role in skeletal muscle function by promoting differentiation. Show less

The cholesteryl ester transfer protein (CETP) system moves cholesteryl esters (CE) from high density lipoproteins (HDL) to lower density lipoproteins, i.e. very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) in exchange for triglycerides (TGs). This shuttle process will ultimately form complexes facilitating a bidirectional exchange of CE and TGs, the end process being CE delivery to catabolic sites. The CETP system is generally characteristic of higher animal species; lower species, not provided with this system, have higher and enlarged HDL enriched with apo E, suitable for tissue receptor interaction. Discovery of the CETP system has led to the development of agents interfering with CETP, thus elevating HDL-C and potentially preventing cardiovascular (CV) disease. Activation of CETP leads instead to reduced HDL-C levels, but also to an enhanced removal of CE from tissues. CETP antagonists are mainly small molecules (torcetrapib, anacetrapib, evacetrapib, dalcetrapib) and have provided convincing evidence of a HDL-C raising activity, but disappointing results in trials of CV prevention. In contrast, the CETP agonist probucol leads to HDL-C lowering followed by an increment of tissue cholesterol removal (reduction of xanthomas, xanthelasmas) and positive findings in secondary prevention trials. The drug has an impressive anti-inflammatory profile (markedly reduced interleukin-1β expression). Newer agents, some of natural origin, have additional valuable pharmacodynamic properties. The pharmacological approach to the CETP system remains enigmatic, although the failure of CETP antagonists has dampened enthusiasm. Studies on the system, a crossroad for any investigation on cholesterol metabolism, have however provided crucial contributions and will still be confronting any scientist working on CV prevention. Show less

Heparan sulfate (HS), a linear polysaccharide, is involved in diverse biological functions of various tissues. HS is expressed in pancreatic β-cells and may be involved in β-cell functions. However, the importance of HS for β-cell function remains unknown. Here, we generated mice with β-cell-specific deletion of Ext1 (βExt1CKO), which encodes an enzyme essential for HS synthesis, to investigate the detailed roles of HS in β-cell function. βExt1CKO mice decreased body weights compared with control mice, despite increased food intake. Additionally, βExt1CKO mice showed impaired glucose tolerance associated with decreased insulin secretion upon glucose challenge. Glucose-induced insulin secretion (GIIS) from isolated βExt1CKO islets was also significantly reduced, highlighting the contribution of HS to insulin secretion and glucose homeostasis. The gene expression essential for GIIS was decreased in βExt1CKO islets. Pdx1 and MafA were downregulated in βExt1CKO islets, indicating that HS promoted β-cell development and maturation. BrdU- or Ki67-positive β-cells were reduced in βExt1CKO pancreatic sections, suggesting the involvement of HS in the proliferation of β-cells. Moreover, insufficient vascularization in βExt1CKO islets may contribute to central distribution of α-cells. These data demonstrate HS plays diverse roles in β-cells, and that loss of HS leads to insufficient insulin secretion and dysregulation of glucose homeostasis. Show less

The stability of β-catenin is very important for canonical Wnt signaling. A protein complex including Axin/APC/GSK3β phosphorylates β-catenin to be degraded by ubiquitination with β-TrCP. In the recent study, we isolated WDR26, a protein that binds to Axin. Here, we found that WDR26 is a negative regulator of the canonical Wnt signaling pathway, and that WDR26 affected β-catenin levels. In addition, WDR26/Axin binding is involved in the ubiquitination of β-catenin. These results suggest that WDR26 plays a negative role in β-catenin degradation in the Wnt signaling pathway. Show less

The predominant risk factor of metabolic syndrome is intra-abdominal fat accumulation, which is determined by waist circumference, waist-hip ratio measurements and visceral fat area (VFA); the latter can be accurately measured by performing computed tomography (CT). In addition to environmental factors, genetic factors play an important role in obesity and fat distribution. New genetic loci associated with body mass index (BMI) and adiposity have been identified by genome-wide association studies (GWASs). This study utilized CT to investigate whether single nucleotide polymorphisms (SNPs) that confer susceptibility to higher BMI are associated with VFA, subcutaneous fat area (SFA), and the ratio of VFA to SFA (V/S ratio). We measured the VFA and SFA of 1424 obese Japanese subjects (BMI ≥ 25 kg/m(2), 635 men and 789 women) who were genotyped for 13 single nucleotide polymorphisms (SNPs) reported by recent GWASs, namely, TNNI3K rs1514175, PTBP2 rs1555543, ADCY3 rs713586, IRS1 rs2943650, POC5 rs2112347, NUDT3 rs206936, LINGO2 rs10968576, STK33 rs4929949, MTIF3 rs4771122, SPRY2 rs534870, MAP2K5 rs2241423, QPCTL rs2287019, and ZC3H4 rs3810291. The G-allele of NUDT3 rs206936 was significantly associated with increased BMI (P = 5.3 × 10(-5)) and SFA (P = 0.00039) in the obese Japanese women. After adjustment with BMI, the association between rs206936 and SFA was not observed. This significant association was not observed in the men. The other SNPs analyzed were not significantly associated with BMI, VFA, SFA, or V/S ratio. Our results suggest that NUDT3 rs206936 is associated with BMI in Japanese women. Show less

Metabolic syndrome is defined as a cluster of multiple risk factors, including central obesity, dyslipidemia, hypertension and impaired glucose tolerance, that increase cardiovascular disease morbidity and mortality. Genetic factors are important in the development of metabolic syndrome, as are environmental factors. However, the genetic background of metabolic syndrome is not yet fully clarified. There is evidence that obesity and obesity-related phenotypes are associated with variations in several genes, including NEGR1, SEC16B, TMEM18, ETV5, GNPDA2, BDNF, MTCH2, SH2B1, FTO, MAF, MC4R, KCTD15, SCG3, MTMR9, TFAP2B, MSRA, LYPLAL1, GCKR and FADS1. To investigate the relationship between metabolic syndrome and variations in these genes in the Japanese population, we genotyped 33 single-nucleotide polymorphisms (SNPs) in 19 genes from 1096 patients with metabolic syndrome and 581 control individuals who had no risk factors for metabolic syndrome. Four SNPs in the FTO gene were significantly related to metabolic syndrome: rs9939609 (P=0.00013), rs8050136 (P=0.00011), rs1558902 (P=6.6 × 10(-5)) and rs1421085 (P=7.4 × 10(-5)). rs3764220 in the SCG3 gene (P=0.0010) and rs2293855 in the MTMR9 gene (P=0.0015) were also significantly associated with metabolic syndrome. SNPs in the FTO, SCG3 and MTMR9 genes had no SNP × SNP epistatic effects on metabolic syndrome. Our data suggest that genetic variations in the FTO, SCG3 and MTMR9 genes independently influence the risk of metabolic syndrome. Show less

Visceral fat accumulation has an important role in increasing morbidity and mortality rate by increasing the risk of developing several metabolic disorders, such as type 2 diabetes, dyslipidemia and hypertension. New genetic loci that contribute to the development of obesity have been identified by genome-wide association studies in Caucasian populations. We genotyped 1279 Japanese subjects (556 men and 723 women), who underwent computed tomography (CT) for measuring visceral fat area (VFA) and subcutaneous fat area (SFA), for the following single-nucleotide polymorphisms (SNPs): NEGR1 rs2815752, SEC16B rs10913469, TMEM18 rs6548238, ETV5 rs7647305, GNPDA2 rs10938397, BDNF rs6265 and rs925946, MTCH2 rs10838738, SH2B1 rs7498665, MAF rs1424233, and KCTD15 rs29941 and rs11084753. In the additive model, none of the SNPs were significantly associated with body mass index (BMI). The SH2B1 rs7498665 risk allele was found to be significantly associated with VFA (P=0.00047) but not with BMI or SFA. When the analysis was performed in men and women separately, no significant associations with VFA were observed (P=0.0099 in men and P=0.022 in women). None of the other SNPs were significantly associated with SFA. Our results suggest that there is a VFA-specific genetic factor and that a polymorphism in the SH2B1 gene influences the risk of visceral fat accumulation. Show less

The predominant risk factor of metabolic syndrome is intra-abdominal fat accumulation, which is determined by waist circumference and waist-hip ratio measurements and visceral fat area (VFA) that is measured by computed tomography (CT). There is evidence that waist circumference and waist-hip ratio in the Caucasian population are associated with variations in several genes, including neurexin 3 (NRXN3), transcription factor AP-2β (TFAP2B), methionine sulfoxide reductase A (MSRA), lysophospholipase-like-1 (LYPLAL1), fat mass and obesity associated (FTO) and melanocortin 4 receptor (MC4R) genes. To investigate the relationship between VFA and subcutaneous fat area (SFA) and these genes in the recruited Japanese population, we genotyped 8 single-nucleotide polymorphisms (SNPs) in these 6 genes from 1228 subjects. Multiple regression analysis revealed that gender, age, and rs1558902 and rs1421085 genotypes (additive model) in FTO were significantly associated with body mass index (BMI; P=0.0039 and 0.0039, respectively), SFA (P=0.0027 and 0.0023, respectively) and VFA (P=0.045 and 0.040, respectively). However, SNPs in other genes, namely, NRXN3, TFAP2B, MSRA, LYPLAL1 and MC4R were not significantly associated with BMI, SFA or VFA. Our data suggest that some SNPs, which were identified in genome-wide studies in the Caucasians, also confer susceptibility to fat distribution in the Japanese subjects. Show less

There is evidence that the obesity phenotype in the Caucasian populations is associated with variations in several genes, including neuronal growth regulator 1 (NEGR1), SEC16 homolog B (SCE16B), transmembrane protein 18 (TMEM18), ets variant 5 (ETV5), glucosamine-6-phosphate deaminase 2 (GNPDA2), prolactin (PRL), brain-derived neurotrophic factor (BDNF), mitochondrial carrier homolog 2 (MTCH2), Fas apoptotic inhibitory molecule 2 (FAIM2), SH2B adaptor protein 1 (SH2B1), v-maf musculoaponeurotic fibrosarcoma oncogene homolog (MAF), Niemann-Pick disease, type C1 (NPC1), melanocortin 4 receptor (MC4R) and potassium channel tetramerisation domain containing 15 (KCTD15). To investigate the relationship between obesity and these genes in the Japanese population, we genotyped 27 single-nucleotide polymorphisms (SNPs) in 14 genes from obese subjects (n=1129, body mass index (BMI) > or =30 kg m(-2)) and normal-weight control subjects (n=1736, BMI <25 kg m(-2)). The SNP rs10913469 in SEC16B (P=0.000012) and four SNPs (rs2867125, rs6548238, rs4854344 and rs7561317) in the TMEM18 gene (P=0.00015), all of which were in almost absolute linkage disequilibrium, were significantly associated with obesity in the Japanese population. SNPs in GNPDA2, BDNF, FAIM2 and MC4R genes were marginally associated with obesity (P<0.05). Our data suggest that some SNPs identified by genome-wide association studies in the Caucasians also confer susceptibility to obesity in Japanese subjects. Show less

We studied the association of six common polymorphisms of four genes related to lipid metabolism with serum lipid levels. We selected single-nucleotide polymorphisms (SNPs) in the genes for cholesteryl ester transfer protein (CETP), lipoprotein lipase (LPL), hepatic lipase (LIPC), and apolipoprotein CIII (APOC3), and studied 2267 individuals randomly selected from the participants of Serum Lipid Survey 2000. There was a significant association of CETP polymorphism (D442G, Int14 +1 G --> A, and TaqIB), LPL polymorphism (S447X), and LIPC polymorphism (-514 --> CT) with HDL-cholesterol levels. We also found a significant association of LPL polymorphism (S447X) and APOC3 polymorphism (SstI) with triglyceride levels. This is the largest database showing the association of common genetic variants in lipid metabolism with serum lipid levels in the general Japanese population. Further study is necessary to elucidate the role of these gene polymorphisms in cardiovascular events. Show less