👤 Hironobu Eguchi

In the PEMA-FL study in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), pemafibrate was shown to significantly decrease low-density lipoprotein cholesterol (LDL-C) levels. We aimed to investigate the mechanisms of pemafibrate-induced LDL-C reduction in patients with MASLD by conducting an additional sub-analysis of the PEMA-FL study. The PEMA-FL study randomized 118 patients with MASLD to receive pemafibrate or placebo for 72 weeks. This sub-analysis examined the percentage change in LDL-C and related lipid markers by tertile of baseline LDL-C levels and the correlation between these changes in the pemafibrate group. Pemafibrate significantly decreased LDL-C levels approximately 25% (p＜0.001 at all timepoints) from baseline in the highest tertile of baseline LDL-C levels (≥ 137.5 mg/dL), with similar trends for non-high-density lipoprotein cholesterol (non-HDL-C) and apolipoprotein B (ApoB) levels. Lipoprotein (a) [Lp(a)] levels decreased only in patients with the highest baseline LDL-C levels. Regardless of the baseline LDL-C levels, pemafibrate altered the LDL particle profile (increased LDL particle size and decreased the number); reduced lathosterol, β-sitosterol, and campesterol; and increased angiopoietin-like protein 3 (ANGPTL3). The percentage change in LDL-C positively correlated with that in ApoB, non-HDL-C, Lp(a), lathosterol, β-sitosterol, and campesterol but not HDL-C and ANGPTL3. Pemafibrate reduced LDL-C, ApoB, and non-HDL-C levels in patients with MASLD, and the effect was greater in those with higher baseline LDL-C levels. Pemafibrate may clinically benefit patients with MASLD by improving LDL-C levels and the LDL particle profile. Show less

Fibroblast growth factor 2 (FGF2)regulates signal transduction by forming complexes with its receptors, FGF receptors (FGFRs), and heparan sulfate (HS), playing a crucial role in biological systems. Although HS has been suggested to modulate FGF/FGFR signaling as a coreceptor, multiple hypotheses exist regarding how HS affects FGF/FGFR signaling and the mechanism remains unclear. Herein, to highlight the role of FGF2/HS interaction in FGF2/FGFR1 signaling, FGF2 mutants with reduced HS-binding affinity are rationally designed through in silico analysis. These FGF2 mutants exhibit reduced HS affinity by more than two orders of magnitude while maintaining binding affinity to FGFR1. In addition, these mutants retain their thermal stability. Cellular assays using the FGF2 mutant suggest that, contrary to previous reports, the contribution of the FGF2/HS interaction in FGF2/FGFR1 signaling may be limited. The mutant FGFs that specifically alter the interaction with HS, achieved in this study, would contribute to an understanding of the role of FGF/HS interaction in FGF/FGFR signaling. Show less

The prevalence of gestational diabetes mellitus (GDM) is significantly increasing. Hyperglycaemia and dyslipidaemia have been demonstrated to contribute to endothelial dysfunction linked to foetal-placental circulation. Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) is crucial for the lipolytic processing of TG-rich lipoproteins through the anchoring of lipoprotein lipase (LPL). In this study, circulating GPIHBP1 levels during pregnancy were evaluated, and their associations with hypertriglyceridaemia and the perinatal outcomes of GDM were evaluated. This study included 12 pregnant women with GDM and 21 pregnant women with normal glucose tolerance (NGT). No significant differences in obstetrical outcomes were detected between the two groups. In participants with NGT, circulating GPIHBP1 levels were markedly lower in the 3rd trimester than in the 2nd trimester and at delivery. In women with GDM, circulating GPIHBP1 levels were unchanged during the 3rd trimester, and circulating GPIHBP1 levels throughout the 3 Our findings suggest a possible association between circulating GPIHBP1 levels and perinatal outcomes in patients with GDM. Show less

DNA aptamers have attracted attention as an alternative modality for biomolecules due to their excellent target binding specificity and thermal stability, and they are also expected to be applied as artificial agonists for receptor proteins. DNA aptamer agonist TD0 targeting the receptor of fibroblast growth factor (FGFR), which plays an important role in the fields of wound healing and regenerative medicine, has been reported to induce cellular responses as well as its native ligands. However, it was also noted that there were some different responses upon long-term stimulation, suggesting that the intracellular signals induced by DNA aptamer agonist TD0 are different from those of natural ligands. In this paper, we comprehensively analyzed the intracellular signals induced by DNA aptamer agonist TD0 targeting FGFR1, and compared them with those by natural protein ligand FGF2. It was found that the intracellular signals were highly similar for short-term stimulation. On the other hand, the receptor and the downstream cellular signals showed different activation behaviors for long-time stimulation. Evaluating the stability and sustained activity of DNA aptamer agonist TD0 and FGF2 in the medium suggested that ligand stability may be important in properly regulating cellular responses. Show less

In diabetes, the impairment of insulin secretion and insulin resistance contribute to hypertriglyceridemia, as the enzymatic activity of lipoprotein lipase (LPL) depends on insulin action. The transport of LPL to endothelial cells and its enzymatic activity are maintained by the formation of lipolytic complex depending on the multiple positive (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 [GPIHBP1], apolipoprotein C-II [APOC2], APOA5, heparan sulfate proteoglycan [HSPG], lipase maturation factor 1 [LFM1] and sel-1 suppressor of lin-12-like [SEL1L]) and negative regulators (APOC1, APOC3, angiopoietin-like proteins [ANGPTL]3, ANGPTL4 and ANGPTL8). Among the regulators, GPIHBP1 is a crucial molecule for the translocation of LPL from parenchymal cells to the luminal surface of capillary endothelial cells, and maintenance of lipolytic activity; that is, hydrolyzation of triglyceride into free fatty acids and monoglyceride, and conversion from chylomicron to chylomicron remnant in the exogenous pathway and from very low-density lipoprotein to low-density lipoprotein in the endogenous pathway. The null mutation of GPIHBP1 causes severe hypertriglyceridemia and pancreatitis, and GPIGBP1 autoantibody syndrome also causes severe hypertriglyceridemia and recurrent episodes of acute pancreatitis. In patients with type 2 diabetes, the elevated serum triglyceride levels negatively correlate with circulating LPL levels, and positively with circulating APOC1, APOC3, ANGPTL3, ANGPTL4 and ANGPTL8 levels. In contrast, circulating GPIHBP1 levels are not altered in type 2 diabetes patients with higher serum triglyceride levels, whereas they are elevated in type 2 diabetes patients with diabetic retinopathy and nephropathy. The circulating regulators of lipolytic complex might be new biomarkers for lipid and glucose metabolism, and diabetic vascular complications. Show less

Chromosome instability is one of the hallmarks of cancer. Stromal antigen (STAG) 3 is a core component of the meiosis-specific cohesin complex, which regulates sister chromatid cohesion. Although aberrantly activated genes encoding the cohesin complex have been identified in cancers, little is known about the role of STAG3 in colorectal cancer (CRC). Here, we evaluated the prognostic impact and role of STAG3 in CRC. Analysis of 172 CRC surgical specimens revealed that high STAG3 expression was associated with poor prognosis. STAG3 knockdown inhibited cell migration and increased drug sensitivity to oxaliplatin, 5-fluorouracil, irinotecan hydrochloride hydrate, and BRAF inhibitor in CRC cell lines. The enhanced drug sensitivity was also confirmed in a human organoid established from a CRC specimen. Moreover, suppression of STAG3 increased γH2AX foci. Particularly, in BRAF-mutant CRC cells, STAG3 silencing suppressed the expression of snail family transcriptional repressor 1 and phosphorylation of extracellular signal-regulated kinase via upregulation of dual-specificity phosphatase 6. Our findings suggest that STAG3 is related to poor clinical outcomes and promotes metastasis and chemotherapeutic resistance in CRC. STAG3 may be a novel prognostic marker and potential therapeutic target for CRC. Show less

Mycoplasma bovis is a pathogenic bacterium in bovines that causes huge global economic losses. Numerous factors play important roles in M. bovis pathogenesis; however, the host immune response involved in M. bovis infection has not been fully elucidated. We aimed to determine the characteristics of the host immune response to Mycoplasma infection. We evaluated the responsiveness of bovine peripheral blood mononuclear cells (PBMCs) stimulated with M. bovis via microarray analysis. The transcriptional abundance of innate immune-related genes IL-36A, IL-27, IFN-γ, and IL-17 in PBMCs increased after M. bovis exposure. Upon M. bovis infection, there was increased expression of the lymphocyte activated genes basic leucine zipper transcription factor (BATF) and signaling lymphocytic activation molecule family members 1 and 7 (SLAMF 1 and SLAMF 7) in PBMCs compared with that in unstimulated cells. The study revealed that the transcriptional abundance of innate immunity genes in PBMCs increased during M. bovis infection. This induced the activation of PBMCs, giving rise to an immune response, which is followed by the development of the inflammatory response. The results from this study could be used as the basis for the development of novel vaccine candidates against M. bovis. Show less

The carbohydrate response element binding protein (ChREBP) is a glucose-responsive transcription factor that increases the transcription of multiple genes. ChREBP is highly localized in the liver, where it upregulates the expression of genes that code for glycolytic and lipogenic enzymes, resulting in the conversion of excess carbohydrate into storage fat. ChREBP knockout (KO) mice display an anti-obese phenotype. However, at this time, role of ChREBP in adipose tissue remains unclear. Therefore, the energy metabolism and morphology of mitochondrial brown adipose tissue (BAT) in ChREBP KO mice was examined. We found increased expression levels of electron transport system proteins including the mitochondrial uncoupling protein (UCP1), and mitochondrial structural alterations such as dysplasia of the cristae and the presence of small mitochondria in BAT of ChREBP KO mice. Mass spectrometry analyses revealed that fatty acid synthase was absent in the BAT of ChREBP KO mice, which probably led to a reduction in fatty acids and cardiolipin, a regulator of various mitochondrial events. Our study clarified the new role of ChREBP in adipose tissue and its involvement in mitochondrial function. A clearer understanding of ChREBP in mitochondria could pave the way for improvements in obesity management. Show less

Subcutaneous transplantation of engineered hepatocyte/fibroblast sheets (EHFSs) is a low invasive and safe approach to construct vascularized subcutaneous human liver tissue (VSLT). However, the liver-specific structures and functionalities in the development process of VSLTs in mice remain poorly understood. Here, we describe time-dependent characteristics of the formation of the vascular network, cell-cell adhesions, liver transporters, liver-specific protein synthesis, and metabolizing activities. The EHFSs formed multilayered thick tissues by rapid neovascularization, which allows overcoming extremely difficult problems, such as the lack of oxygen supply on the formation of three-dimensional primary hepatocyte tissue under the skin. The blood vessels consisted of mouse-origin endothelial cells (ECs) (mVEGFR2) from the subcutaneous space at 1-7 days, and the following formation of the vascular network was performed by human-origin ECs (hVEGFR2). Many varieties of liver-specific gene expressions increased with the construction of the VSLTs: cell-cell adhesion molecules (CDH1, CLDN3, and CX32), transporters at basal (OATP1A1, OCT1, and NTCP) and apical membranes (MRP2, MDR1, and BSEP), blood coagulation factors (F8 and F9), urea synthesis (CPS1, OTC, and ARG1), and metabolism enzymes (CYP7A1, CYP1A2, CYP2B6, CYP3A4, and UGT1A1). Subacute hepatic failure model mice with VSLT were alive at least 7 weeks after liver damage. Thus, the ectopic liver organ offers the potential for a low invasive and safe treatment for liver diseases. Show less

Here, we explored the genetic interactions between diabetes and oncogenic single-nucleotide polymorphisms (SNPs) that determine colorectal cancer (CRC) morbidity. 8q24 rs6983267 polymorphism analysis and cDNA microarray were performed in 107 CRCs to identify the genes associated with diabetes and the oncogenic SNP. Then clinical significance of the gene was validated in 132 CRCs. Meta-analysis of microarray data and diabetic comorbidity was performed. Of genes associated with a minor SNP allele at 8q24, diabetes, and MYC overexpression, apolipoprotein A-IV (ApoA-IV) was associated with oncogenesis and poor prognosis in CRC patients. Patients with high ApoA-IV expression showed significantly poorer prognosis by univariate and multivariate analysis. Meta-analysis revealed lipid metabolism was associated with ApoA-IV-related oncogenesis in diabetic patients. Changes in lipid metabolism associated with aberrant expression of ApoA-IV were risks for CRC oncogenesis. Show less

NFAT5 is an osmoregulated transcription factor that particularly increases expression of genes involved in protection against hypertonicity. Transcription factors often contain unstructured regions that bind co-regulatory proteins that are crucial for their function. The NH2-terminal region of NFAT5 contains regions predicted to be intrinsically disordered. We used peptide aptamer-based affinity chromatography coupled with mass spectrometry to identify protein preys pulled down by one or more overlapping 20 amino acid peptide baits within a predicted NH2-terminal unstructured region of NFAT5. We identify a total of 467 unique protein preys that associate with at least one NH2-terminal peptide bait from NFAT5 in either cytoplasmic or nuclear extracts from HEK293 cells treated with elevated, normal, or reduced NaCl concentrations. Different sets of proteins are pulled down from nuclear vs. cytoplasmic extracts. We used GeneCards to ascertain known functions of the protein preys. The protein preys include many that were previously known, but also many novel ones. Consideration of the novel ones suggests many aspects of NFAT5 regulation, interaction and function that were not previously appreciated, for example, hypertonicity inhibits NFAT5 by sumoylating it and the NFAT5 protein preys include components of the CHTOP complex that desumoylate proteins, an action that should contribute to activation of NFAT5. Show less

The lens of the eye is composed of fiber cells, which differentiate from epithelial cells and undergo programmed organelle degradation during terminal differentiation. Although autophagy, a major intracellular degradation system, is constitutively active in these cells, its physiological role has remained unclear. We have previously shown that Atg5-dependent macroautophagy is not necessary for lens organelle degradation, at least during the embryonic period. Here, we generated lens-specific Atg5 knock-out mice and showed that Atg5 is not required for lens organelle degradation at any period of life. However, deletion of Atg5 in the lens results in age-related cataract, which is accompanied by accumulation of polyubiquitinated and oxidized proteins, p62, and insoluble crystallins, suggesting a defect in intracellular quality control. We also produced lens-specific Pik3c3 knock-out mice to elucidate the possible involvement of Atg5-independent alternative autophagy, which is proposed to be dependent on Pik3c3 (also known as Vps34), in lens organelle degradation. Deletion of Pik3c3 in the lens does not affect lens organelle degradation, but it leads to congenital cataract and a defect in lens development after birth likely due to an impairment of the endocytic pathway. Taken together, these results suggest that clearance of lens organelles is independent of macroautophagy. These findings also clarify the physiological role of Atg5 and Pik3c3 in quality control and development of the lens, respectively. Show less

The carbohydrate response element-binding protein (ChREBP) functions as a transcription factor in mediating the glucose-activated gene expression of multiple liver enzymes, which are responsible for converting excess carbohydrate to storage fat. ChREBP is translocated into the nucleus in response to high glucose levels, and then up-regulates transcriptional activity. Although this glucose activation of ChREBP is generally observed only in liver cells, overexpression of wild type max-like protein X (Mlx), but not an inactive mutant Mlx, resulted in the exhibition of the ChREBP functions also in a human kidney cell line. Because high glucose conditions induce the glycosylation of cellular proteins, the effect of O-linked GlcNAc modification on ChREBP functions was examined. Treatment with an O-GlcNAcase inhibitor (PUGNAc), which increases the O-linked GlcNAc modification of cellular proteins, caused an increase in the glucose response of ChREBP. In contrast, treatment with a glutamine fructose amidotransferase inhibitor (DON), which decreases O-GlcNAcylation by inhibiting the hexosamine biosynthetic pathway, completely blocked the glucose response of ChREBP. These results suggest that the O-linked glycosylation of ChREBP itself or other proteins that regulate ChREBP is essential for the production of functional ChREBP. Show less