Browsing by Subject "GPBAR1"

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    Distribution of bile acid receptor TGR5 in the gastrointestinal tract of dogs
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2019) Giaretta, Paula R.; Suchodolski, Jan S.; Blick, Anna K.; Steiner, Joerg M.; Lidbury, Jonathan A.; Rech, Raquel R.
    Takeda-G-protein-receptor-5 (TGR5) is a receptor for bile acids and its expression has been described in a variety of tissues and species. Characterization of TGR5 distribution and function has been investigated in drug discovery for the treatment of metabolic diseases in humans. Because dogs are one of the species used in biomedical research and share some similarities with human gastrointestinal diseases, the objective of this study was to characterize the distribution of TGR5 receptor in the canine species. This study characterizes the distribution of TGR5 receptor in the gastrointestinal tract, liver, gallbladder, and pancreas of 8 dogs. The distribution of TGR5 antigen and mRNA expression was investigated using immunohistochemistry and RNA in situ hybridization, respectively. TGR5 immunolabeling was located in the cell membrane or in the cell membrane and cytoplasm. TGR5 immunolabeling was broadly distributed in macrophages, endothelial cells, ganglion cells, and leiomyocytes throughout all the examined tissues. Epithelial cells from tongue, stomach to rectum, as well as from gallbladder, biliary and pancreatic ducts demonstrated TGR5 immunolabeling. In endocrine cells, TGR5 immunolabeling was observed in intestinal enteroendocrine cells and islets of Langerhans in the pancreas. The hepatocytes had a unique pattern of immunolabeling located on the canalicular surface of the cell membrane. TGR5 mRNA expression was located mainly in the nucleus and the only negative cells throughout all examined tissues were striated muscle from tongue and esophagus, muscularis mucosae, esophageal glands, and hepatic sinusoids. These findings indicate that the bile acid receptor TGR5 is ubiquitously distributed in the canine gastrointestinal tract.
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    GPBAR1 promotes proliferation and is related to poor prognosis of high-grade glioma via inducing MAFB expression
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2022) Sun, Suohui; Guo, Hui; Liang, Nan; Wu, Tao; Zhang, Chunpu; Li, Huaqing
    Background. Glioma is the most prevalent brain tumors with extremely poor prognosis, but the prognostic biomarkers of high-grade (grade III and IV) gliomas (HGG) are still insufficient. Materials and methods. In our study, we investigated the expression of GPBAR1 in HGG by qRT-PCR and immunohistochemistry (IHC), and evaluated the clinical significance of GPBAR1 with univariate and multivariate analyses. By retrieving the data from TCGA, we screened the genes significantly associated with GPBAR1, and identified the correlation between GPBAR1 and MAFB. By experiments in vitro, we showed the pivotal role of MAFB in GPBAR1-induced proliferation of HGG. Results. GPBAR1 expression in HGGs was significantly higher than that in normal brain tissues. GPBAR1 was an independent prognostic biomarker of HGG. GPBAR1 promoted the proliferation of HGG by inducing MAFB expression. MAFB was also a prognostic biomarker of HGG, and patients with coexpression of MAFB and GPBAR1 had worse prognosis. Conclusions. GPBAR1 promoted the proliferation of HGG by inducing MAFB expression. Both GPBAR1 and MAFB were prognostic biomarkers of HGG, and patients with co-expression of MAFB and GPBAR1 had worse prognosis than those with only GPBAR1 or MAFB expression.