👤 Hiroki Kawano

Mangiferin, a chemical constituent of Mangifera indica, has been the subject of extensive investigation due to its diverse biological activities, as detailed in numerous scientific studies. Its aglycone, norathyriol, has similarly garnered attention from researchers. In furtherance of our ongoing research goals, this article presents an evaluation of these compounds in relation to biomarkers associated with Alzheimer's disease. The inhibition of acetylcholinesterase (AChE) and β-secretase (BACE-1), as well as the aggregation of the amyloid beta (Aβ)42 peptide, was assessed using Ellman's colourimetric method, fluorescence resonance energy transfer (FRET), and thioflavin-T fluorescence emission, respectively. Mangiferin exhibited no inhibitory effect on AChE, whereas norathyriol demonstrated an inhibitory concentration (IC50) of 6.23 μM. Molecular docking revealed that the mangiferin-AChE and mangiferin-BACE-1 complexes did not interact with sites related to enzyme activity. In contrast, norathyriol showed favourable interactions with Asp72 at the peripheral site of AChE and formed significant interactions with BACE-1 through hydrogen bonds, as suggested by molecular docking. The IC50 of norathyriol for BACE-1 inhibition was found to be 9.75 μM. The reduction in Aβ42 aggregation by norathyriol was only 28%. We conclude that norathyriol is a promising prototype for drug development aimed at treating Alzheimer's disease. Show less

Multi-organ regulation underlies metabolic health, especially in the context of adipose-liver dysfunction during obesity. Previous findings identified Melinjo seed extract (MSE) as a promising modulator of metabolic disorders, although its active component remained unknown. Gnetin C, a trans-resveratrol dimer from MSE, likely serves as the key factor, yet its direct metabolic role remains unclear. Here, Gnetin C was administered to high-fat diet (HFD)-fed mice, which significantly improved body weight and fasting glucose, attributed to enhanced adiponectin (APN) multimerization. In adipose tissue, Gnetin C directly promotes APN multimerization and suppresses fat accumulation by up-regulating the PPARγ-DsbA-L axis, while concurrently modulating hepatic Sirt1, which may contribute to increased FGF21 production. This paracrine FGF21 signaling, suggested by elevated Fgfr1 in hepatocytes and βKlotho in adipocytes, further augments APN multimerization. These findings underscore the importance of a multi-tissue approach to obesity management and position Gnetin C as an integrative therapeutic candidate, restoring metabolic balance via dual adipose and hepatic effects in HFD mice. Show less

Histologic transformation from adenocarcinoma to SCLC is a recognized mechanism of resistance in lung cancer. However, the transformation into squamous cell carcinoma is less common, and the associated genomic alterations remain unclear. Here, we present a case of lung adenocarcinoma harboring an EGFR ( Show less

Fibroblast growth factor (FGF) signaling plays a crucial role in several cellular functions in cancer cells. Tasurgratinib, formerly known as E7090, is an orally available FGF receptor (FGFR)1-3 selective inhibitor. Here, we present the effects of tasurgratinib on the resistance to CDK4/6 inhibitors and endocrine therapy (ET) in a preclinical model. Estrogen receptor (ER) Among five ER FGF signaling plays a role in resistance to CDK4/6 inhibitors and ET in ER Show less

Cholangiocarcinoma (CCA) is an aggressive tumor with limited treatment options especially in 2nd line or later treatments. Targeting fibroblast growth factor receptor (FGFR) 2 has recently emerged as a promising treatment option for patients with CCA harboring FGFR2-fusion. This study investigated the antitumor activities of tasurgratinib as an orally available FGFR1-3 inhibitor, in preclinical FGFR2-driven CCA models. Antitumor activities of tasurgratinib were examined in vitro and in vivo using NIH/3T3 cells expressing FGFR2-fusion as FGFR2-driven CCA models, and in vivo using a CCA patient-derived xenograft model. The molecular mechanism of action of tasurgratinib was elucidated through co-crystal structure analysis with FGFR1, manual complex model analysis with FGFR2, and binding kinetics analysis with FGFR2. Furthermore, the cell-based inhibitory activities against acquired resistant FGFR2 mutations in patients with CCA treated with FGFR inhibitors were evaluated. Tasurgratinib showed antitumor activity in preclinical FGFR2-driven CCA models by inhibiting the FGFR signaling pathway in vitro and in vivo. Furthermore, cell-based target engagement assays indicated that tasurgratinib had potent inhibitory activities against FGFR2 mutations, such as N549H/K, which are the major acquired mutations in CCA. We also confirmed that tasurgratinib exhibited fast association and slow dissociation kinetics with FGFR2, binding to the ATP-binding site and the neighboring region, and adopting an Asp-Phe-Gly (DFG)-"in" conformation. These data demonstrate the therapeutic potential of tasurgratinib in FGFR2-driven CCA and provide molecular mechanistic insights into its unique inhibitory profile against secondary FGFR2 resistance mutations in patients with CCA treated with FGFR inhibitors. Show less

Myeloid and lymphoid neoplasms associated with FGFR1 abnormalities (MLN-FGFR1 abnormalities) are rare hematologic malignancies associated with chromosome 8p11.2 abnormalities. Translocations of 8p11.2 were detected in 10 of 17,039 (0.06%) unique patient cytogenetic studies performed at nine institutions in Japan. No inversions or insertions of 8p11.2 were detected. Among the 10 patients with 8p11.2 translocations, three patients were diagnosed with MLN-FGFR1 abnormalities, which were confirmed by FISH analysis. Peripheral blood eosinophilia was observed in all three patients, and all progressed to AML or T-lymphoblastic lymphoma/leukemia. The prevalence of 8p11.2 translocations in clinical practice and the proportion of MLN-FGFR1 abnormalities in patients with 8p11.2 translocations in Japan were consistent with those in previous reports from Western countries. Show less

The mobilization efficiency of hematopoietic stem/progenitor cells from bone marrow (BM) to circulation by granulocyte colony-stimulating factor (G-CSF) is dramatically dispersed in humans and mice with no mechanistic lead for poor mobilizers. The regulatory mechanism for mobilization efficiency by dietary fat was assessed in mice. Fat-free diet (FFD) for 2 weeks greatly increased mobilization compared to normal diet (ND). The BM mRNA level of peroxisome proliferator-activated receptor δ (PPARδ), a receptor for lipid mediators, was markedly up-regulated by G-CSF in mice fed with ND and displayed strong positive correlation with widely scattered mobilization efficiency. It was hypothesized that BM fat ligand for PPARδ might inhibit mobilization. The PPARδ agonist inhibited mobilization in mice fed with ND and enhanced mobilization by FFD. Treatment with the PPARδ antagonist and chimeric mice with PPARδ+/- BM showed enhanced mobilization. Immunohistochemical staining and flow cytometry revealed that BM PPARδ expression was enhanced by G-CSF mainly in mature/immature neutrophils. BM lipid mediator analysis revealed that G-CSF treatment and FFD resulted in the exhaustion of ω3-polyunsaturated fatty acids such as eicosapentaenoic acid (EPA). EPA induced the up-regulation of genes downstream of PPARδ, such as carnitine palmitoyltransferase-1α and angiopoietin-like protein 4 (Angptl4), in mature/immature neutrophils in vitro and inhibited enhanced mobilization in mice fed with FFD in vivo. Treatment of wild-type mice with the anti-Angptl4 antibody enhanced mobilization together with BM vascular permeability. Collectively, PPARδ signaling in BM mature/immature neutrophils induced by dietary fatty acids negatively regulates mobilization, at least partially, via Angptl4 production. Show less

Hepatocyte growth factor (HGF) is an endogenously induced bioactive molecule that has strong anti-apoptotic and tissue repair activities. In this research, we identified APOA4 as a novel pharmacodynamic (PD) marker of the recombinant human HGF (rh-HGF), E3112. rh-HGF was administered to mice, and their livers were investigated for the PD marker. Candidates were identified from soluble proteins and validated by using human hepatocytes in vitro and an animal disease model in vivo, in which its c-Met dependency was also ensured. Among the genes induced or highly enhanced after rh-HGF exposure in vivo, a soluble apolipoprotein, APOA4 was identified as a soluble PD marker of rh-HGF with c-Met dependency. It should be worthwhile to clinically validate its utility through clinical trials with healthy subjects and ALF patients. Show less

Phospholipid transfer protein gene knock-out (Pltp KO) mice have defective transfer of very low density lipoprotein (VLDL) phospholipids into high density lipoprotein (HDL) and markedly decreased HDL levels (Jiang et al. 1999. J. Clin. Invest. 103: 907-914). These animals also accumulated VLDL- and LDL-sized lipoproteins on a high saturated fat diet. The goals of this study were to further characterize the abnormal lipoproteins of Pltp KO mice and to determine the mechanisms responsible for low HDL levels. A lipoprotein fraction enriched in lamellar structures was isolated from the low density lipoprotein (LDL) region and was shown to be phospholipid- and free cholesterol-rich and to have apoA-IV (55%) and apoE (25%) as major apolipoproteins. The lamellar lipoproteins accumulating in these mice probably represent surface material derived from triglyceride-rich lipoproteins (TRL). The HDL was found to be protein-rich (primarily apoA-I) and specifically depleted in phosphatidylcholine (PC) (28% in wild-type mice (WT) vs. 15% in Pltp KO mice, P < 0.001). Unexpectedly, turnover studies using autologous HDL revealed a profound 4-fold increase in the catabolism of HDL protein and cholesteryl ester in Pltp KO mice compared to wild-type, with minor differences in synthesis rates. In contrast, injection of WT mouse HDL into Pltp KO mice showed only a 2-fold increase in fractional catabolism. Reminiscent of the defect in Tangier disease, the failure of transfer of PC from TRL into the HDL fraction results in dramatic hypercatabolism of HDL. These results suggest that defective phospholipid transfer from TRL into HDL, arising from decreased lipolysis or decreased PLTP activity, could lead to hypoalphalipoproteinemia characterized by hypercatabolism of HDL protein. lipoprotein levels, due to hypercatabolism, and accumulate apoA-IV-rich lamellar lipoproteins. Show less