Kyoto University

About: Kyoto University is a education organization based out in Kyoto, Japan. It is known for research contribution in the topics: Catalysis & Population. The organization has 85837 authors who have published 217215 publications receiving 6526826 citations. The organization is also known as: Kyōto University & Kyōto daigaku.

Preferential Generation of Follicular B Helper T Cells from Foxp3+ T Cells in Gut Peyer's Patches

Abstract: Most of the immunoglobulin A (IgA) in the gut is generated by B cells in the germinal centers of Peyer's patches through a process that requires the presence of CD4+ follicular B helper T(TFH) cells. The nature of these T(FH) cells in Peyer's patches has been elusive. Here, we demonstrate that suppressive Foxp3+CD4+ T cells can differentiate into TFH cells in mouse Peyer's patches. The conversion of Foxp3+ T cells into TFH cells requires the loss of Foxp3 expression and subsequent interaction with B cells. Thus, environmental cues present in gut Peyer's patches promote the selective differentiation of distinct helper T cell subsets, such as TFH cells.

Dysfunction of lipid sensor GPR120 leads to obesity in both mouse and human

Abstract: Free fatty acids provide an important energy source as nutrients, and act as signalling molecules in various cellular processes. Several G-protein-coupled receptors have been identified as free-fatty-acid receptors important in physiology as well as in several diseases. GPR120 (also known as O3FAR1) functions as a receptor for unsaturated long-chain free fatty acids and has a critical role in various physiological homeostasis mechanisms such as adipogenesis, regulation of appetite and food preference. Here we show that GPR120-deficient mice fed a high-fat diet develop obesity, glucose intolerance and fatty liver with decreased adipocyte differentiation and lipogenesis and enhanced hepatic lipogenesis. Insulin resistance in such mice is associated with reduced insulin signalling and enhanced inflammation in adipose tissue. In human, we show that GPR120 expression in adipose tissue is significantly higher in obese individuals than in lean controls. GPR120 exon sequencing in obese subjects reveals a deleterious non-synonymous mutation (p.R270H) that inhibits GPR120 signalling activity. Furthermore, the p.R270H variant increases the risk of obesity in European populations. Overall, this study demonstrates that the lipid sensor GPR120 has a key role in sensing dietary fat and, therefore, in the control of energy balance in both humans and rodents.

Autoantibodies against cardiac troponin I are responsible for dilated cardiomyopathy in PD-1-deficient mice

Abstract: We recently reported that mice deficient in the programmed cell death-1 (PD-1) immunoinhibitory coreceptor develop autoimmune dilated cardiomyopathy (DCM), with production of high-titer autoantibodies against a heart-specific, 30-kDa protein. In this study, we purified the 30-kDa protein from heart extract and identified it as cardiac troponin I (cTnI), encoded by a gene in which mutations can cause familial hypertrophic cardiomyopathy (HCM). Administration of monoclonal antibodies to cTnI induced dilatation and dysfunction of hearts in wild-type mice. Monoclonal antibodies to cTnI stained the surface of cardiomyocytes and augmented the voltage-dependent L-type Ca2+ current of normal cardiomyocytes. These findings suggest that antibodies to cTnI induce heart dysfunction and dilatation by chronic stimulation of Ca2+ influx in cardiomyocytes.

Poly(ADP-ribose) and ADP-ribosylation of proteins.

Abstract: Publisher Summary This chapter analyzes poly(ADP-ribose) and ADP-ribosylation of proteins. Poly(ADP-ribose) and the ADP-ribosylation of proteins constitute a novel type of covalent modification of proteins. They are ubiquitously distributed in nature and are implicated in the regulation of cell proliferation, protein synthesis, and DNA as well as RNA metabolism. This type of post-translational modification is unique because NAD, nicotinamide adenine dinucleotide, whose primary function is an electron carrier in biological oxidation, invariably provides the ADP-ribosyl moiety, which is transferred on to a protein molecule. The ADP-ribosyl unit thus, covalently attached to a protein acceptor is present as either a monomer or a polymer as in the case of the nuclear system. This chapter also summarizes developments in this field of research and some experimental results. It reviews briefly, mono ADP-ribosylation of proteins, in which only a single ADP-ribosyl moiety is transferred to a protein acceptor. It also covers a more complex reaction, poly(ADP-ribose) in nuclei, in which the ADP-ribosyl units are polymerized.