Tomomi Kimura

A Single Nucleotide Polymorphism in the Carboxylesterase Gene Is Associated with the Responsiveness to Imidapril Medication and the Promoter Activity

Imidapril is an angiotensin-converting enzyme inhibitor that is widely used in treating hypertension, although the responses vary among individuals. We investigated whether a single nucleotide polymorphism at position −816 of the carboxylesterase 1 (CES1) gene, which activates imidapril in the liver, is involved in the responsiveness to imidapril medication. A total of 105 Japanese hypertensives with systolic/diastolic blood pressures (SBP/DBP) of 140/90 mmHg or higher were prescribed 5–10 mg/day of imidapril. At baseline, blood pressure levels were not different between patients with and those without the −816C allele (AA vs. AC+CC groups). After 8 weeks of treatment, we classified the responders and non-responders based on the decline in their blood pressures, and found that the responder rate was significantly higher in the AC+CC group than in the AA group (p=0.0331). Also, the reduction in SBP was significantly greater in the AC+CC group than in the AA group (24.7±11.8 vs. 17.6±16.8 mmHg, p=0.0184). Furthermore, an in vitro reporter assay revealed that the −816C construct had significantly higher promoter activity (p<0.0001). These findings suggest that the A(−816)C polymorphism affects the transcriptional activity, and that this may account for the responsiveness to imidapril.

NOS3 Genotype–Dependent Correlation Between Blood Pressure and Physical Activity

Abstract—Endothelium-dependent vasorelaxation plays an important role in reduction of blood pressure and is mediated through release of nitric oxide (NO), which is generated by constitutively expressed endothelial nitric oxide synthase (NOS3). Exercise also augments NO release and has been recommended for primary prevention and improvement of hypertension, but individual responses are highly variable. We therefore postulated that genetic polymorphisms of NOS3 might interact with physical activity level to differentially influence blood pressure level. We genotyped 832 healthy Japanese (mean age of 54.4±8.6 years, 372 men and 460 women) for a polymorphism of NOS3 in intron 4 (ecNOS4a/b), using the polymerase chain reaction method, and scored their habitual physical activity level by using the rate of energy expenditure per resting metabolic rate through an interview according to a semiquantitative assessment method. Only in the subjects who had the rarer a allele (aa +ba type), systolic blood pressure was found to be inversely correlated with physical activity level (P for linear trend=0.0496, for interaction=0.0071). Eventually, this polymorphism was significantly associated with the prevalence of systolic hypertension only in the subjects who were in the lowest tertile of physical activity level (OR=2.4, 95% CI, 1.1 to 5.6, P for interaction=0.0474). In the present study, we found a significant interaction between the genotype and physical activity level on systolic blood pressure. These results might allow a better understanding of the mechanism to improve hypertension by exercise and to thereby reduce the risk of cardiovascular disease.

Association of Transforming Growth Factor–β1 Functional Polymorphisms with Natural Clearance of Hepatitis C Virus

Transforming growth factor (TGF)-beta 1 suppresses the proliferation and cytotoxicity of natural killer (NK) cells, which play critical roles in resolving hepatitis C virus (HCV) infection, especially during the acute phase. We examined 230 anti-HCV antibody-positive subjects for HCV RNA and the -509T/C genotype in the TGF-beta 1 gene promoter. The -509CC genotype and the -509C allele were significantly associated with higher HCV clearance rates (P=.01) and with lower transcriptional activity. The genetic effect remained significant even after adjustment for a history of transfusion. Low TGF- beta 1 producers might have less suppression of NK cells and be more likely to resolve HCV infection.

SPK-1, a C. elegans SR protein kinase homologue, is essential for embryogenesis and required for germline development.

SR-protein kinases (SRPKs) and their substrates, serine/arginine-rich pre-mRNA splicing factors, are key components of splicing machinery and are well conserved across phyla. Despite extensive biochemical investigation, the physiological functions of SRPKs remain unclear. In the present study, cDNAs for SPK-1, a C. elegans SRPK homologue, and CeSF2, an SPK-1 substrate, were cloned. SPK-1 binds directly to and phosphorylates the RS domain of CeSF2 in vitro. Both spk-1 and CeSF2 are predominantly expressed in germlines. RNA interference (RNAi) experiments revealed that spk-1 and CeSF2 play an essential role at the embryonic stage of C. elegans. Furthermore, RNAi studies demonstrated that spk-1 is required for germline development in C. elegans. We provide evidence that RNAi, achieved by the soaking of L1 larvae, is beneficial in the study of gene function in post-embryonic germline development.

Interaction of angiotensin I-converting enzyme insertion-deletion polymorphism and daily salt intake influences hypertension in Japanese men.

The contribution of angiotensin I–converting enzyme insertion-deletion polymorphism (ACE I/D) to salt-sensitivity hypertension has been extensively studied by means of salt-loading tests, but whether or not the interaction with daily salt intake affects blood pressure still remains to be clarified. We therefore conducted a cross-sectional study of 284 Japanese male workers (age range, 20–64 years) to examine the effect of ACE I/D genotype and daily salt intake on hypertension. Blood pressure was measured and the ACE I/D was identified by polymerase chain reaction (PCR). Daily salt intake was calculated from a food frequency questionnaire (FFQ). In multivariate analyses, we explored the interaction of ACE I/D and salt intake by means of logistic regression analysis and multiple linear regression analysis. ACE I/D per se was not associated with blood pressure levels or hypertension. ACE I/D interacted with daily salt intake and correlated with hypertension (p for interaction=0.047). In the ID+II genotype, hypertension was increased by high salt intake (p=0.005), while in the DD genotype it was not (p=0.257). The interaction was more prominent in the overweight group (p=0.039) than in non-overweight group. In the overweight group, high salt intake induced a 10.5 mmHg higher diastolic blood pressure in the ID+II genotype than in the DD genotype (p=0.042). Our results suggest that ACE I/D and daily salt intake constitute a gene-environment interaction, which may be further modulated by overweight.

Effect of concurrent elemental diet on infliximab treatment for Crohn’s disease

Background:  Infliximab and elemental diet (ED) have been shown to be effective in the management of Crohn’s disease. However, few experiences have been reported regarding their combination therapy. The aim of the present study was to investigate the efficacy and safety of infliximab in Japanese patients, the first such study in Asia, as well as the effect of concomitant ED.

A Lower Level of Forced Expiratory Volume in 1 Second Is a Risk Factor for All-Cause and Cardiovascular Mortality in a Japanese Population: The Takahata Study

Chronic obstructive pulmonary disease is a known risk factor for cardiovascular death in Western countries. Because Japan has a low cardiovascular death rate, the association between a lower level of forced expiratory volume in 1 s (FEV1) and mortality in Japan’s general population is unknown. To clarify this, we conducted a community-based longitudinal study. This study included 3253 subjects, who received spirometry from 2004 to 2006 in Takahata, with a 7-year follow-up. The causes of death were assessed on the basis of the death certificate. In 338 subjects, airflow obstruction was observed by spirometry. A total of 127 subjects died. Cardiovascular death was the second highest cause of death in this population. The pulmonary functions of the deceased subjects were significantly lower than those of the subjects who were alive at the end of follow-up. The relative risk of death by all causes, respiratory failure, lung cancer, and cardiovascular disease was significantly increased with airflow obstruction. The Kaplan–Meier analysis showed that all-cause and cardiovascular mortality significantly increased with a worsening severity of airflow obstruction. After adjusting for possible factors that could influence prognosis, a Cox proportional hazard model analysis revealed that a lower level of FEV1 was an independent risk factor for all-cause and cardiovascular mortality (per 10% increase; hazard ratio [HR], 0.89; 95% confidence interval [CI], 0.82–0.98; and HR, 0.72; 95% CI, 0.61–0.86, respectively). In conclusion, airflow obstruction is an independent risk factor for all-cause and cardiovascular death in the Japanese general population. Spirometry might be a useful test to evaluate the risk of cardiovascular death and detect the risk of respiratory death by lung cancer or respiratory failure in healthy Japanese individuals.

C3123A polymorphism of the angiotensin II type 2 receptor gene and salt sensitivity in healthy Japanese men

Our cross-sectional study shows that the angiotensin II type 2 receptor (AGTR2) 3123A allele is an important determinant of the blood pressure response to dietary salt intake in middle-aged Japanese men. Although future research is required to elucidate for the association between AGTR2 genotype and the blood pressure response to dietary salt intake in prospective studies and for the mechanisms of the AGTR2 gene and salt sensitivity, it can be said that the AGTR2 genotype is a potentially useful genetic marker of salt sensitivity.

Reduced Number and Morphofunctional Change of Alveolar Macrophages in MafB Gene-Targeted Mice

Alveolar macrophages (AMs) play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). We previously demonstrated that the transcription factor, MafB, increased in the AMs of mice exposed to cigarette smoke, and in those of human patients with COPD. The aim of this study was to evaluate the role of MafB in AMs using newly established transgenic (TG) mice that specifically express dominant negative (DN) MafB in macrophages under the control of macrophage scavenger receptor (MSR) enhancer-promoter. We performed cell differential analyses in bronchoalveolar lavage cells, morphological analyses with electron microscopy, and flow cytometry-based analyses of surface markers and a phagocytic capacity assay in macrophages. AM number in the TG mice was significantly decreased compared with wild-type (WT) mice. Morphologically, the high electron density area in the nucleus increased, the shape of pseudopods on the AMs was altered, and actin filament was less localized in the pseudopods of AMs of TG mice, compared with WT mice. The expression of surface markers, F4/80 and CD11b, on peritoneal macrophages in TG mice was reduced compared with WT mice, while those on AMs remained unchanged. Phagocytic capacity was decreased in AMs from TG mice, compared with WT mice. In conclusion, MafB regulates the phenotype of macrophages with respect to the number of alveolar macrophages, the nuclear compartment, cellular shape, surface marker expression, and phagocytic function. MSR-DN MafB TG mice may present a useful model to clarify the precise role of MafB in macrophages.

Gly80Ser Polymorphism of Phospholipase A2-IID Is Associated with Cytokine Inducibility in A549 Cells

Background: The Gly80Ser polymorphism in phospholipase A2-IID (PLA2G2D, NCBI SNP reference: rs584367) is associated with a loss in body weight in patients with chronic obstructive pulmonary disease (COPD). The T allele missense mutation results in the 80th amino acid of the PLA2G2D protein changing from a glycine (Gly; C allele) to a serine (Ser; T allele). COPD patients carrying Ser lose a significant amount of weight compared with those carrying Gly. The mechanism for this weight loss following carriage of this Ser allele has not been clarified. Objectives: We aimed to evaluate whether this allelic change alters PLA2 enzymatic activity and/or pro-inflammatory cytokine inducibility. Methods: A549 cells (a human pulmonary epithelial cell line) were transfected with PLA2G2D-Gly or PLA2G2D-Ser. We evaluated PLA2 activity and cytokine expressions in these cells. Results: The enzymatic activity of sPLA2 in A549-PLA2G2D-Ser cells did not differ from the A549-PLA2G2D-Gly cells. A549-PLA2G2D-Ser cells spontaneously produced higher levels of interleukin (IL)-6 and IL-8 than A549-PLA2G2D-Gly cells. Upon tumor necrosis factor-α stimulation, IL-6 and IL-8 mRNA and protein levels in A549-PLA2G2D-Ser cells were elevated compared with those of A549-PLA2G2D-Gly cells. Upon hydrogen peroxide stimulation, IL-8 mRNA and protein levels in A549-PLA2G2D-Ser cells were higher than those of A549-PLA2G2D-Gly cells. Conclusions:PLA2G2D-Ser enhances the expression of IL-6 and IL-8 compared with PLA2G2D-Gly. This enhanced cytokine expression observed with the allelic change in PLA2G2D may be associated with the body weight loss seen in COPD patients.