Japanese Lifestyle during Childhood Prevents the Future Development of Obesity among Japanese-Americans

Objective

To evaluate whether a Japanese lifestyle during childhood could protect against the future development of obesity-associated metabolic diseases by comparing native Japanese with Japanese-Americans in whom genetic factors are the same.

Methods

Study subjects were 516 native Japanese and 781 Japanese-Americans who underwent medical examinations between 2007 and 2010. Japanese-Americans were divided into 444 first-generation immigrants (JA-1), who were born in Japan, and 337 second- or later-generation descendants (JA-2), who were born in the United States. The JA-2 group was then divided into the kibei subgroup (N = 79), who had moved to Japan before the age of 18 years and later returned to the United States, and the non-kibei subgroup (N = 258), who had never lived in Japan.

Results

The JA-2 group had the highest percentages of obesity, metabolic syndrome, and type 2 diabetes compared with native Japanese and JA-1. Furthermore, among JA-2, the prevalence of obesity and metabolic syndrome in the kibei subgroup was significantly lower than that in the non-kibei subgroup. The prevalence of diabetes in the kibei subgroup also tended to be lower than in the non-kibei subgroup.

Conclusions

The prevalence of obesity and metabolic diseases differed with residence in Japan during childhood among Japanese-Americans. These findings indicate the possibility that Japanese lifestyle during childhood could reduce the future risks for obesity-associated metabolic diseases.     

Novel frame-shift mutation in Slc5a2 encoding SGLT2 in a strain of senescence-accelerated mouse SAMP10

The senescence-accelerated mouse prone10 (SAMP10) strain, a model of aging, exhibits cognitive impairments and cerebral atrophy. We noticed that SAMP10/TaSlc mice, a SAMP10 substrain, have developed persistent glucosuria over the past few years. In the present study, we characterized SAMP10/TaSlc mice and further identified a spontaneous mutation in the Slc5a2 gene encoding sodium-glucose co-transporter (SGLT) 2. The mean concentration of urine glucose was high in SAMP10/TaSlc mice and increased further with advancing age, whereas other strains of senescence-accelerated mice, including SAMP1/SkuSlc, SAMP6/TaSlc and SAMP8/TaSlc or normal aging control SAMR1/TaSlc mice, exhibited no detectable glucose in urine. SAMP10/TaSlc mice consumed increasing amounts of food and water compared to SAMR1/TaSlc mice, suggesting the compensation of polyuria and the loss of glucose. Oral glucose tolerance tests showed decreased glucose reabsorption in the kidney of SAMP10/TaSlc mice. In addition, blood glucose levels decreased in an age-dependent fashion. The kidney was innately larger than that of control mice with no histological alterations. We examined the expression levels of glucose transporters in the kidney. Among SGLT1, SGLT2, glucose transporter (GLUT) 1 and GLUT2, we found a significant decrease only in the level of SGLT2. DNA sequencing of SGLT2 in SAMP10/TaSlc mice revealed a single nucleotide deletion of guanine at 1236, which resulted in a frameshift mutation that produced a truncated protein. We designate this strain as SAMP10/TaSlc-Slc5a2^slc (SAMP10-ΔSglt2). Recently, SGLT2 inhibitors have been demonstrated to be effective for the treatment of patients with type 2 diabetes (T2D). SAMP10-ΔSglt2 mice may serve as a unique preclinical model to study the link between aging-related neurodegenerative disorders and T2D.     

Autoantibodies to angiotensin-converting enzyme 2 in patients with connective tissue diseases

Introduction  

Angiotensin-converting enzyme (ACE) 2, a homolog of ACE, converts angiotensin (Ang) II into Ang(1-7), and the vasoprotective effects of Ang(1-7) have been documented. We explored the hypothesis that serum autoantibodies to ACE2 predispose patients with connective tissue diseases to constrictive vasculopathy, pulmonary arterial hypertension (PAH), or persistent digital ischemia.     

Phylogenomic Analyses Reveal the Evolutionary Origin of the Inhibin α-Subunit,a Unique TGFβ Superfamily Antagonist

Transforming growth factor-beta (TGFβ) homologues form a diverse superfamily that arose early in animal evolution and control cellular function through membrane-spanning, conserved serine-threonine kinases (RII and RI receptors). Activin and inhibin are related dimers within the TGFβ superfamily that share a common β-subunit. The evolution of the inhibin α-subunit created the only antagonist within the TGFβ superfamily and the only member known to act as an endocrine hormone. This hormone introduced a new level of complexity and control to vertebrate reproductive function. The novel functions of the inhibin α-subunit appear to reflect specific insertion-deletion changes within the inhibin β-subunit that occurred during evolution. Using phylogenomic analysis, we correlated specific insertions with the acquisition of distinct functions that underlie the phenotypic complexity of vertebrate reproductive processes. This phylogenomic approach presents a new way of understanding the structure-function relationships between inhibin, activin, and the larger TGFβ superfamily.     

Protective role of macrophages in noninflammatory lung injury caused by selective ablation of alveolar epithelial type II Cells

Macrophages have a wide variety of activities and it is largely unknown how the diverse phenotypes of macrophages contribute to pathological conditions in the different types of tissue injury in vivo. In this study we established a novel animal model of acute respiratory distress syndrome caused by the dysfunction of alveolar epithelial type II (AE2) cells and examined the roles of alveolar macrophages in the acute lung injury. The human diphtheria toxin (DT) receptor (DTR), heparin-binding epidermal growth factor-like growth factor (HB-EGF), was expressed under the control of the lysozyme M (LysM) gene promoter in the mice. When DT was administrated to the mice they suffered from acute lung injury and died within 4 days. Immunohistochemical examination revealed that AE2 cells as well as alveolar macrophages were deleted via apoptosis in the mice treated with DT. Consistent with the deletion of AE2 cells, the amount of surfactant proteins in bronchoalveolar lavage fluid was greatly reduced in the DT-treated transgenic mice. When bone marrow from wild-type mice was transplanted into irradiated LysM-DTR mice, the alveolar macrophages became resistant to DT but the mice still suffered from acute lung injury by DT administration. Compared with the mice in which both AE2 cells and macrophages were deleted by DT administration, the DT-treated LysM-DTR mice with DT-resistant macrophages showed less severe lung injury with a reduced amount of hepatocyte growth factor in bronchoalveolar lavage fluid. These results indicate that macrophages play a protective role in noninflammatory lung injury caused by the selective ablation of AE2 cells.     

Impaired activity of volume-sensitive Cl- channel is involved in cisplatin resistance of cancer cells

The platinum-based drug cisplatin is a widely used anticancer drug which acts by causing the induction of apoptosis. However, resistance to the drug is a major problem. In this study we show that the KCP-4 human epidermoid cancer cell line, which serves as a model of acquired resistance to cisplatin, has virtually no volume-sensitive, outwardly rectifying (VSOR) chloride channel activity. The VSOR chloride channel's molecular identity has not yet been determined, and semi-quantitative RT-PCR experiments in this study suggested that the channel corresponds to none of three candidate genes. However, because it is known that the channel current plays an essential role in apoptosis, we hypothesized that lack of the current contributes to cisplatin resistance in these cells and that its restoration would reduce resistance. To test this hypothesis, we attempted to restore VSOR chloride current in KCP-4 cells. It was found that treatment with trichostatin A (TSA), a histone deacetylase inhibitor, caused VSOR chloride channel function to be partially restored. Treatment of the cells with both TSA and cisplatin resulted in an increase in caspase-3 activity at 24 h and a decrease in cell viability at 48 h. These effects were blocked by simultaneous treatment of the cells with a VSOR chloride channel blocker. These results indicate that restoration of the channel's functional expression by TSA treatment leads to a decrease in the cisplatin resistance of KCP-4 cells. We thus conclude that impaired activity of the VSOR chloride channel is involved in the cisplatin resistance of KCP-4 cancer cells.     

Characterization of a broadly reactive monoclonal antibody against norovirus genogroups I and II: recognition of a novel conformational epitope

Norovirus, which belongs to the family Caliciviridae, is one of the major causes of nonbacterial acute gastroenteritis in the world. The main human noroviruses are of genogroup I (GI) and genogroup II (GII), which were subdivided further into at least 15 and 18 genotypes (GI/1 to GI/15 and GII/1 to GII/18), respectively. The development of immunological diagnosis for norovirus had been hindered by the antigen specificity of the polyclonal antibody. Therefore, several laboratories have produced broadly reactive monoclonal antibodies, which recognize the linear GI and GII cross-reactive epitopes or the conformational GI-specific epitope. In this study, we characterized the novel monoclonal antibody 14-1 (MAb14-1) for further development of the rapid immunochromatography test. Our results demonstrated that MAb14-1 could recognize 15 recombinant virus-like particles (GI/1, 4, 8, and 11 and GII/1 to 7 and 12 to 15) and showed weak affinity to the virus-like particle of GI/3. This recognition range is the broadest of the existing monoclonal antibodies. The epitope for MAb14-1 was identified by fragment, sequence, structural, and mutational analyses. Both terminal antigenic regions (amino acid positions 418 to 426 and 526 to 534) on the C-terminal P1 domain formed the conformational epitope and were in the proximity of the insertion region (positions 427 to 525). These regions contained six amino acids responsible for antigenicity that were conserved among genogroup(s), genus, and Caliciviridae. This epitope mapping explained the broad reactivity and different titers among GI and GII. To our knowledge, we are the first group to identify the GI and GII cross-reactive monoclonal antibody, which recognizes the novel conformational epitope. From these data, MAb14-1 could be used further to develop immunochromatography.