Kyoto University · Medicine
Professor Hiroyuki Yoshitomi's research lab focuses on the immunological mechanisms underlying chronic inflammatory diseases, particularly rheumatoid arthritis (RA). The lab investigates the roles of innate and adaptive immune cells—such as T cells, B cells, and fibroblast-like synoviocytes—in driving inflammation and tissue destruction. Key research directions include the identification of pathogenic T cell subsets (e.g., Tph and PD-1⁺CXCR5⁻ T cells) that promote ectopic lymphoid structure formation and CXCL13 production, as well as the role of pattern recognition receptors and microRNAs as biomarkers and therapeutic targets. The lab integrates human tissue studies with in vitro and in vivo models to uncover novel immunoregulatory pathways in autoimmunity.
Figures are computed from collected data and may differ slightly.
A combination of genetic and environmental factors can cause autoimmune disease in animals. SKG mice, which are genetically prone to develop autoimmune arthritis, fail to develop the disease under a microbially clean condition, despite active thymic production of arthritogenic autoimmune T cells and their persistence in the periphery. However, in the clean environment, a single intraperitoneal injection of zymosan, a crude fungal beta-glucan, or purified beta-glucans such as curdlan and laminari
The interactions of CD4<sup>+</sup> T cells and B cells are fundamental for the generation of protective antibody responses, as well as for the development of harmful autoimmune diseases. Recent studies of human tissues and blood samples have established a new subset of CD4<sup>+</sup> B helper T cells named peripheral helper T (Tph) cells. Unlike T follicular helper (Tfh) cells, which interact with B cells within lymphoid organs, Tph cells provide help to B cells within inflamed tissues. Tph ce
Synovial tissue is a membranous non-immune organ lining joint cavities where it supports local immune responses, and functions directly and indirectly in joint destruction due to chronic inflammatory diseases such as rheumatoid arthritis (RA). Fibroblast-like synoviocytes (FLS), the dominant non-immune cells of synovial tissues, mainly contribute to joint destruction via multiple mechanisms. In RA, FLS respond to endogenous ligands of pattern recognition receptors (PRRs) and inflammatory cytokin
MicroRNAs (miRNAs) are present in human plasma and known as a non-invasive biomarker for cancer detection. Our study was designed to identify plasma miRNAs specific for rheumatoid arthritis (RA) by a comprehensive array approach. We performed a systematic, array-based miRNA analysis on plasma samples from three RA patients and three healthy controls (HCs). Plasma miRNAs with more than four times change or with significant (P<0.05) change in expression, or detectable only in RA plasma, were confi
In human inflammatory sites, PD-1<sup>hi</sup>CXCR5<sup>-</sup>CD4<sup>+</sup> T cells are involved in the formation of ectopic lymphoid-like structures (ELSs) by the secretion of chemokine CXCL13, but how the transcription of CXCL13 is regulated in CD4<sup>+</sup> T cells is still unclear. Here we show that Sox4 is a key transcription factor for CXCL13 production in human CD4<sup>+</sup> T cells under inflammatory conditions. In vitro TGF-β<sup>+</sup>, IL-2-neutralizing culture conditions give
In the ectopic lymphoid-like structures present in chronic inflammatory conditions such as rheumatoid arthritis, a subset of human effector memory CD4(+) T cells that lacks features of follicular helper T (Tfh) cells produces CXCL13. Here, we report that TGF-β induces the differentiation of human CXCL13-producing CD4(+) T cells from naïve CD4(+) T cells. The TGF-β-induced CXCL13-producing CD4(+) T cells do not express CXCR5, B-cell lymphoma 6 (BCL6), and other Tfh-cell markers. Furthermore, expr
Reduction of AAS has a negative effect on the oropharyngeal airway space. Therefore, reduction of AAS during occipitocervical fusion may cause postoperative dysphagia despite maintenance of the O-C2A.
Long-term administration of nicorandil has been shown to improve outcomes through cardioprotective effects in patients with coronary artery disease. To identify the mechanisms responsible for these effects, this study examined the impact of long-term nicorandil administration on endothelial function, systemic inflammatory markers, and oxidative stress in patients with cardiovascular risk factors. Fifty-three patients were assigned to receive either nicorandil therapy (15 mg/day; n = 26) (nicoran
A series of rheumatoid arthritis (RA) studies established a PD-1<sup>hi</sup>CXCR5<sup>-</sup>CD4<sup>+</sup> T-cell subset that was coined peripheral helper T (Tph) cells. CXCL13 production is a key feature of Tph cells and may contribute to the formation of tertiary lymphoid structures (TLS) in inflamed tissues. In addition, Tph cells provide help to B cells <i>in situ</i> as efficiently as follicular helper T (Tfh) cells, and these features would implicate Tph cells in the pathogenesis of RA.
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