👤 Kazuhiro Furuhashi

Hyperglycemia-induced effects on cellular metabolic properties and reactive oxygen species (ROS) generation play pivotal roles in the pathogenesis of malignant melanoma (MM). This study assessed how metabolic states, ROS production, and related gene expression are modulated by antidiabetic agents. The anti-diabetic agents metformin (Met) and imeglimin (Ime), inhibitors of fatty acid-binding proteins 5/7 (MF6) and microphthalmia-associated transcription factor (MITF) (ML329), and siRNA-mediated knockdown of angiopoietin-like protein 4 (ANGPTL4), which affect mitochondrial respiration, ROS production, and related gene expression, were tested in A375 (MM cell line) cells cultured in low (5.5 mM) and high glucose (50 mM) conditions. Cellular metabolic functions were significantly and differently modulated by Met, Ime, MF6, or ML329 and knockdown of ANGPTL4. High glucose significantly enhanced ROS production, which was alleviated by Ime but not by Met. Both MF6 and ML329 reduced ROS levels under both low and high glucose conditions. Knockdown of ANGPTL4 enhanced the change in glucose-dependent ROS production. Gene expression related to mitochondrial respiration and the pathogenesis of MM was significantly modulated by different glucose conditions, antidiabetic agents, MF6, and ML329. These findings suggest that glucose-dependent changes in cellular metabolism and redox status are differently modulated by antidiabetic agents, inhibition of fatty acid-binding proteins or MITF, and ANGPTL4 knockdown in A375 cells. Show less

Fatty liver index (FLI) calculated by using body mass index, waist circumference and levels of triglycerides and γ-glutamyl transpeptidase is a noninvasive biomarker for diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD), which is one of the high-risk conditions of atherosclerotic cardiovascular diseases. To compare the effects of pemafibrate and omega-3 fatty acid ethyl on FLI, we conducted a sub-analysis study of the Pemafibrate Reduction of triglyceride-rich lipoproteins compared with Omega-3 fatty acid ethyl for Unmet needs in Dyslipidemic patients on target to apoB-48 (PROUD48) study. 57 participants in the pemafibrate 0.4 mg per day treatment group (PEMA, men/women: 37/20, mean 64 years) and 60 participants in the omega-3 fatty acid ethyl 4 g per day treatment group (OMEGA-3, men/women: 35/25, mean 63 years) in the PROUD48 study were included in the present study. Changes in FLI and prevalence of MASLD from baseline to week 16 in PEMA and OMEGA-3 were investigated. Median FLI was significantly decreased by both PEMA (69.7 to 47.6, Pemafibrate is superior to omega-3 fatty acid ethyl in lowering effects of FLI and MASLD in patients with dyslipidemia receiving statin treatment, suggesting that pemafibrate is a beneficial agent for hypertriglyceridemia and reduction of the risk for MASLD. Show less

To elucidate the unidentified roles of a selective peroxisome proliferator-activated receptor α (PPARα) agonist, pemafibrate (Pema), on the pathogenesis of retinal ischemic diseases (RID)s, the pharmacological effects of Pema on the retinal pigment epithelium (RPE), which is involved in the pathogenesis of RID, were compared with the pharmacological effects of the non-fibrate PPARα agonist GW7647 (GW). For this purpose, the human RPE cell line ARPE19 that was untreated (NT) or treated with Pema or GW was subjected to Seahorse cellular metabolic analysis and RNA sequencing analysis. Real-time cellular metabolic function analysis revealed that pharmacological effects of the PPARα agonist actions on essential metabolic functions in RPE cells were substantially different between Pema-treated cells and GW-treated cells. RNA sequencing analysis revealed the following differentially expressed genes (DEGs): (1) NT vs. Pema-treated cells, 37 substantially upregulated and 72 substantially downregulated DEGs; (2) NT vs. GW-treated cells, 32 substantially upregulated and 54 substantially downregulated DEGs; and (3) Pema vs. GW, 67 substantially upregulated and 51 markedly downregulated DEGs. Gene ontology (GO) analysis and ingenuity pathway analysis (IPA) showed several overlaps or differences in biological functions and pathways estimated by the DEGs between NT and Pema-treated cells and between NT and GW-treated cells, presumably due to common PPARα agonist actions or unspecific off-target effects to each. For further estimation, overlaps of DEGs among different pairs of comparisons (NT vs. Pema, NT vs. GW, and Pema vs. GW) were listed up. Angiopoietin-like 4 (ANGPTL4), which has been shown to cause deterioration of RID, was the only DEG identified as a common significantly upregulated DEG in all three pairs of comparisons, suggesting that ANGPTL4 was upregulated by the PPARα agonist action but that its levels were substantially lower in Pema-treated cells than in GW-treated cells. In qPCR analysis, such lower efficacy for upregulation of the mRNA expression of ANGPTL4 by Pema than by GW was confirmed, in addition to substantial upregulation of the mRNA expression of HIF1α by both agonists. However, different Pema and GW-induced effects on mRNA expression of HIF1α (Pema, no change; GW, significantly downregulated) and mRNA expression of ANGPTL4 (Pema, significantly upregulated; GW, significantly downregulated) were observed in HepG2 cells, a human hepatocyte cell line. The results of this study suggest that actions of the PPARα agonists Pema and GW are significantly organ-specific and that lower upregulation of mRNA expression of the DR-worsening factor ANGPTL4 by Pema than by GW in ARPE19 cells may minimize the risk for development of RID. Show less

Renal interstitial fibrosis (RIF) is a common pathological manifestation of chronic kidney diseases. Epithelial-mesenchymal transition (EMT) of tubular epithelial cells is considered a major cause of RIF. Although long non-coding RNAs (lncRNAs) are reportedly involved in various pathophysiological processes, the roles and underlying molecular mechanisms of lncRNAs in the progression of RIF are poorly understood. In this study, we investigated the function of lncRNAs in RIF. Microarray assays showed that expression of the lncRNA lnc-CHAF1B-3 (also called claudin 14 antisense RNA 1) was significantly upregulated in human renal proximal tubular cells by both transforming growth factor-β1 (TGF-β1) and hypoxic stimulation, accompanied with increased expression of EMT-related genes. Knockdown of lnc-CHAF1B-3 significantly suppressed TGF-β1-induced upregulated expression of collagen type I alpha 1, cadherin-2, plasminogen activator inhibitor-1, snail family transcriptional repressor I (SNAI1) and SNAI2. Quantitative reverse transcriptase PCR analyses of paraffin-embedded kidney biopsy samples from IgA nephropathy patients revealed lnc-CHAF1B-3 expression was correlated positively with urinary protein levels and correlated negatively with estimated glomerular filtration rate. Show less