👤 Hiromi Yamashita

Hepatoid adenocarcinoma (HAD) and adenocarcinoma with enteroblastic differentiation (ACED) are rare gastric cancer types that produce alpha-fetoprotein (AFP) that morphologically resembles the liver or fetal organ. This study investigated the molecular profiling of HAD and ACED compared with common-type gastric adenocarcinoma (CGA). This study enrolled 496 patients with gastric adenocarcinoma who underwent radical gastrectomy. Whole-exome sequencing and gene expression profiling were conducted to compare HAD/ACED and CGA. Immunohistochemistry was performed in 39 patients with HAD/ACED, including 10 who underwent genomic analysis. TP53 (100 %), CSMD3 (30 %), LRP1B, FAT3, TG, APOB, CREBBP, PASK, DROSHA, and STK40 (20 %) were mutated genes with high frequency (>20 %) in HAD/ACED. Gene expression analysis revealed 15 overexpressed genes in HAD/ACED, many of which were associated with hepatocytes and fetal organs. Furthermore, cancer stemness gene overexpression, including LIN28B, IGF2BP1, and HMGA2, which are related to TP53, was observed. Immunohistochemistry revealed positive staining for LIN28B (82 %), IGF2BP1 (94 %), and HMGA2 (72 %), as well as staining for AFP (69 %), GPC3 (75 %), and SALL4 (94 %). Additionally, positive cancer stemness gene staining was observed in CGA mucosa coexisting with HAD/ACED. HAD/ACED demonstrated higher TP53 mutation accumulation and TP53-related cancer stemness gene overexpression, including LIN28B, IGF2BP1, and HMGA2. Therefore, TP53 and these cancer stemness genes might be involved in the occurrence of HAD/ACED. Show less

The dysregulated immune system, which drives chronic vascular inflammation and remodeling, plays a critical role in the pathogenesis of abdominal aortic aneurysm (AAA). CCR4 (C-C chemokine receptor 4), which is predominantly expressed on T cells and mediates their responses, has been shown to protect against inflammatory diseases including atherosclerosis. However, its role in AAA remains unknown. By analyzing hypercholesterolemic CCR4-deficient ( Genetic deletion of CCR4 on an CCR4 may serve as a potential therapeutic target for AAA. Show less

Schematic presentation of possible mechanisms of hypertensive dementia, including amyloid beta metabolism (A), NVU dysfunction (B), vulnerability of the hippocampus (C), and activation of RAS (D), and possible new therapeutic approaches for discovering antihypertensive drugs with anti-dementia actions (E). See text for details. Aβ, amyloid β; APP, amyloid β precursor protein; BACE1, β-site amyloid precursor protein cleaving enzyme 1; BBB, blood-brain barrier; CBF, cerebral blood flow; eNOS, endothelial nitric oxide synthase; FDA, Food and Drug Administration; IL, interleukin; NOX, NADPH oxidase; NVU, neurovascular unit; RAS, renin-angiotensin system; ROS, reactive oxygen species. Show less

X-linked adrenoleukodystrophy (X-ALD) is a congenital metabolic disorder characterized mainly by inflammatory demyelination and adrenal insufficiency. Newborn screening using hexacosanoyl lysophosphatidylcholine (C26:0-LPC) in dried blood spots as a diagnostic marker can successfully identify potential patients with X-ALD and prevent disease onset. C26:0-LPC accumulates in patients with X-ALD, although the machinery synthesizing it has remained unclear. In this study, we focused on phosphatidylcholine (PC) with C26:0 moiety as a precursor of C26:0-LPC. We identified that lysophospholipid (LPL) acyltransferase 10 (LPLAT10)/LPCAT4/LPEAT2/AGPAT7 (1-acylglycerol-3-phosphate O-acyltransferase 7) is the responsible LPL acyltransferase that produces PC with C26:0 moiety by transferring C26:0-CoA into 2-acyl-LPC. We also found that LPLAT10 deficiency decreased the amount of C26:0-LPC in fibroblasts from X-ALD patients. Mechanistically, LPLAT10 introduced saturated fatty acid-CoA of various chain lengths as substrates into the sn-1 position of LPC but did not transfer C26:0-CoA to other LPL classes, such as lysophosphatidylethanolamine. Structural analysis revealed that a trimethylamine group of PC was placed between two tryptophan residues (W242 and W244), forming a W-X-W motif, possibly through cation-π interaction. Finally, it was shown that exogenously administered C26:0 FFA-d Show less

Recently, we reported that a pemafibrate extended-release (XR) formulation lowered low-density lipoprotein cholesterol (LDL-C) and cholesterol synthesis and absorption markers in a phase 2 clinical pharmacology study. Here we describe our post-hoc analysis of that study, discuss the mechanism by which pemafibrate lowers LDL-C, and suggest which patients may respond favorably to pemafibrate treatment. In the phase 2 study, patients with hypertriglyceridemia received treatment with pemafibrate immediate-release (IR) 0.2 mg/day or XR 0.4 mg/day or 0.8 mg/day. This post-hoc subgroup analysis examined the percentage change in LDL-C, apolipoprotein B (ApoB), non-HDL-C, and cholesterol synthesis and absorption markers, in subgroups by baseline LDL-C, and then determined the correlation between the percentage change in LDL-C and the percentage change in cholesterol synthesis and absorption markers. Our analysis included 60 patients who received two of three formulations of the drug. A total of 78.3% (47/60) were male, 16.7% (10/60) had type 2 diabetes mellitus, and 10% (6/60) received concomitant statins. The percentage of LDL-C lowering was greater in the population with high baseline LDL-C, and similar trends were noted for the ApoB, non-HDL-C, and cholesterol synthesis and absorption markers. The percentage change in LDL-C was positively correlated with the percentage change in lathosterol, β-sitosterol, and campesterol. In patients with hypertriglyceridemia, results suggested that pemafibrate lowered LDL-C by inhibiting cholesterol synthesis in the liver and cholesterol absorption from the intestinal tract. This lowering effect was greater in populations with higher baseline LDL-C. Show less

Statins can effectively reduce low-density lipoprotein cholesterol (LDL-C), but additional options are needed for inadequate responses to statins or statin intolerance. Bempedoic acid is a small-molecule oral LDL-C-lowering drug that inhibits ATP citrate lyase, an enzyme 2 steps upstream of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the metabolic pathway for cholesterol synthesis. The CLEAR-J trial evaluated bempedoic acid 180 mg/day for 12 weeks in Japanese patients with inadequately controlled LDL-C. Percentage changes in LDL-C between baseline and Week 12 (primary endpoint) were -25.25% and -3.46% in the bempedoic acid and placebo groups, respectively, with a significant between-group difference (-21.78%; 95% confidence interval [CI] -26.71%, -16.85%; P<0.001). Changes in secondary endpoints in the bempedoic acid and placebo groups were as follows: non-high-density lipoprotein cholesterol, -20.33% and -2.76%, respectively (between-group difference -17.57%; 95% CI -22.03%, -13.12%); total cholesterol -16.36% and -2.23%, respectively (between-group difference -14.13%; 95% CI -17.79%, -10.47%); and apolipoprotein B -18.10% and -0.67%, respectively (between-group difference -17.43%; 95% CI -21.97%, -12.89%). At 12 weeks, 62.5% of the bempedoic acid group had achieved target LDL-C values. Treatment-emergent adverse events appeared in 3 patients taking bempedoic acid and 2 patients taking placebo. This study confirmed the safety and efficacy of bempedoic acid after 12 weeks treatment in Japanese patients with high LDL-C who had inadequate response to statins or statin intolerance. Show less

Adiponectin is an anti-diabetic and anti-atherogenic protein secreted primarily from adipose tissue. Adiponectin and modified LDL (mLDL) form a complex to modulate their biological activity. To elucidate the significance of the complex formation, we analyzed its effects on vascular tissue and developed and verified novel quantifying methods for adiponectin. To study the significance of the mLDL-adiponectin complex (MAC) formation, we used the wire-myography method on rat mesenteric artery. We developed a method to measure MAC by using LOX-1 as the capture protein and anti-adiponectin antibody for detection. We compared serum MAC levels between hemodialysis patients and control subjects. Administering mLDL alone to rat mesenteric artery impaired endothelium-dependent vasorelaxation, whereas simultaneously administering adiponectin with mLDL protected rat mesenteric artery from the mLDL-induced impairment of vasorelaxation. This finding indicates MAC formation prevents endothelium from mLDL-induced dysfunction in tissue. Using our novel ELISA for MAC, we found that MAC was increasingly detectable depending on the doses of mLDL and adiponectin in vitro. In serum, hemodialysis patients showed a significantly higher ratio of MAC-high patients (higher than the median level of MAC) than did healthy controls. Furthermore, the MAC-high hemodialysis group had lower mLDL activity measured as LOX-1 ligand containing apoB. Using our ELISA, we detected MAC in human serum that protected blood vessels from the deleterious effects of oxidized LDL. Show less

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

Postprandial hypertriglyceridemia (PHTG) is an independent risk factor for coronary heart diseases. PHTG exhibits accumulation of apoB-48 containing chylomicron remnants (CM-Rs) and apoB-100 containing VLDL remnants (VLDL-Rs), which are both known to be atherogenic. However, unlike VLDL-Rs, structural and functional characterization of CM-Rs remains to be elucidated due to challenges in separating CM-Rs from VLDL-Rs. Recently, we successfully isolated CM-Rs and VLDL-Rs utilizing anti-apoB-48 or apoB-100 specific antibodies. This study aimed to characterize the proteome of CM-Rs along with that of VLDL-Rs. Eight healthy subjects were enrolled. Venous blood was drawn 3 hours after high-fat-containing meals. We isolated CM-Rs and VLDL-Rs from sera through combination of ultracentrifugation and immunoprecipitation using apoB-48 or apoB-100 specific antibodies, followed by shotgun proteomic analysis. We identified 42 CM-Rs or VLDL-Rs-associated proteins, including 11 potential newly identified proteins such as platelet basic protein (PPBP) and platelet factor 4, which are chemokines secreted from platelets. ApoA-I, apoA-IV, and clusterin, which are also known as HDL-associated proteins, were significantly more abundant in CM-Rs. Interestingly, apoC-I, which reduces the activity of lipoprotein lipase and eventually inhibits catabolism of remnant proteins, was also more abundant in CM-Rs. Moreover, we identified proteins involved in complement regulation such as complement C3 and vitronectin, and those involved in acute-phase response such as PPBP, serum amyloid A protein 2, and protein S100-A8, in both CM-Rs and VLDL-Rs. We have firstly characterized the proteome of CM-Rs. These findings may provide an explanation for the atherogenic properties of CM-Rs. Show less

Cholesteryl ester transfer protein (CETP) deficiency is a representative molecular abnormality in familial hyperalphalipoproteinemia, a hereditary disorder of lipid metabolism characterized by markedly elevated plasma high-density lipoprotein cholesterol (HDL-C) levels. In this condition, dysfunction of CETP, which mediates the transfer of cholesteryl esters from HDL particles to apolipoprotein (Apo)B-containing lipoproteins, leads to the abnormal accumulation of HDL-C. These HDL particles are unusually large and enriched in cholesteryl esters, ApoCIII, and ApoE, whereas low-density lipoprotein (LDL) particles are small, depleted of cholesteryl esters, and enriched in triglycerides. Both HDL and LDL particles in CETP deficiency are functionally abnormal. Pemafibrate, a selective peroxisome proliferator-activated receptor α modulator, has consistently been demonstrated in clinical trials to increase HDL-C levels by 16% to 22% in patients with dyslipidemia and low baseline HDL-C. Herein, we describe the unexpected finding of a marked reduction in HDL-C levels in a patient with CETP deficiency following pemafibrate treatment. To better understand this paradoxical response, we analyzed the patient's clinical data and investigated potential mechanisms underlying pemafibrate's effects on HDL metabolism. Show less

An 80-year-old woman with a history of endoscopic balloon dilation for esophageal stricture caused by accidental ingestion of caustic soda during infancy presented with dysphagia. Upper gastrointestinal endoscopy revealed a 10-cm-long, highly white, elevated lesion with a feathered appearance. This lesion was determined to be the cause of dysphagia and was completely resected via endoscopic submucosal dissection. Histopathological examination revealed a thick keratin layer on the surface of the stratified squamous epithelium, with a prominent granular layer underneath and some areas showing nuclear atypia. The lesion was diagnosed as a well-differentiated squamous cell carcinoma, pT1a-LPM, derived from epidermoid metaplasia. Cancer genome analysis revealed mutations in TP53 as well as amplification of MYC, FGFR1, chromosome 7, and chromosome 20q. This case suggests that epidermoid metaplasia caused by chronic irritation from an esophageal stricture may have been exacerbated by the dilation procedure. Show less

Anaplastic thyroid carcinoma (ATC) is considered a very aggressive carcinoma and has been difficult to treat with therapeutic strategies. This study examines the landscape of genomic alteration in ATC, including the BRAF V600E mutation, and its clinical implications. A retrospective observational study was conducted using collected at the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) in Japan, utilizing comprehensive genomic profiling data from 102 ATC cases. Additionally, AACR-GENIE data from 267 cases were analysed for validation. Statistical methods, including the conditional Kendall tau statistic and χ Among 102 ATCs, BRAF, RAS, and other driver mutations were found in 83 cases (81.2%). The prevalence of BRAF V600E mutations was as high as 60%. Co-mutation analysis identified different genomic profiles in the BRAF, RAS, and wild-type groups. Despite the diverse molecular backgrounds, no significant differences in clinical variables and overall survival were observed. The analysis considering left-side amputation suggested that RAS mutations had a poorer prognosis. In the BRAF/RAS wild-type group, FGFR1 and NF1 were identified as driver mutations, with an accumulation of copy number variations and less TERT promoter mutations. This molecular subgrouping was also supported by the AACR-GENIE data. Comprehensive genomic analysis of ATC in Japan revealed distinct molecular subgroups, highlighting the importance of BRAF V600E mutations, particularly V600E, as potential therapeutic targets and suggest the relevance of tailor-made therapeutic strategies based on genomic profiling. 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

Recent genome-wide association studies have revealed that nonalcoholic fatty liver disease (NAFLD) is correlated with genetic polymorphisms. However, the effects of genetic variation on nutritional metabolism and NAFLD are complex and further studies are still needed. This study aimed to assess the nutritional characteristics interacting with the correlation between genetic predisposition and NAFLD. We assessed the 2013-2017 health examination data of 1191 adults aged ≥40 y living in Shika town, Ishikawa Prefecture, Japan. Adults with moderate or heavy alcohol consumption and hepatitis were excluded, and 464 participants who underwent genetic analyses were included in the study. Abdominal echography was performed to diagnose fatty liver condition, and dietary intake and nutritional balance were evaluated using the brief self-administered diet history questionnaire. NAFLD-related gene polymorphisms were identified using Japonica Array v2 (Toshiba). Among the 31 single nucleotide polymorphisms, only the polymorphism T-455C in the apolipoprotein C3 ( The polymorphism T-455C in the Show less

We previously demonstrated that the Alzheimer's disease (AD)-like model mice, Tg2576, housed at a high ambient temperature of 30 °C for 13 months, exhibited increased body temperature, which increased amyloid-β (Aβ) levels and tau stability, leading to tau phosphorylation and ultimately inducing memory impairment. Here, we aimed to exclude the possible effect of environmental factors associated with the difference in ambient temperature (23 °C vs. 30 °C) and to further clarify the effects of elevated body temperature on AD-like pathologies. We generated uncoupling protein 1 (UCP1) deletion in Tg2576 mice, Tg2576/UCP1 Show less

This study aimed to establish variants in CBX1, encoding heterochromatin protein 1β (HP1β), as a cause of a novel syndromic neurodevelopmental disorder. Patients with CBX1 variants were identified, and clinician researchers were connected using GeneMatcher and physician referrals. Clinical histories were collected from each patient. To investigate the pathogenicity of identified variants, we performed in vitro cellular assays and neurobehavioral and cytological analyses of neuronal cells obtained from newly generated Cbx1 mutant mouse lines. In 3 unrelated individuals with developmental delay, hypotonia, and autistic features, we identified heterozygous de novo variants in CBX1. The identified variants were in the chromodomain, the functional domain of HP1β, which mediates interactions with chromatin. Cbx1 chromodomain mutant mice displayed increased latency-to-peak response, suggesting the possibility of synaptic delay or myelination deficits. Cytological and chromatin immunoprecipitation experiments confirmed the reduction of mutant HP1β binding to heterochromatin, whereas HP1β interactome analysis demonstrated that the majority of HP1β-interacting proteins remained unchanged between the wild-type and mutant HP1β. These collective findings confirm the role of CBX1 in developmental disabilities through the disruption of HP1β chromatin binding during neurocognitive development. Because HP1β forms homodimers and heterodimers, mutant HP1β likely sequesters wild-type HP1β and other HP1 proteins, exerting dominant-negative effects. Show less

Global warming is a serious public health threat to people worldwide. High body temperature is one of the important risk factors for Alzheimer's disease (AD), and the body temperature of AD patients has been found to be significantly higher than that of elderly control subjects. However, the effects of high body temperature on cognitive function and AD pathologies have not been completely elucidated. We report here that Tg2576 mice housed at a high ambient temperature of 30 °C for 13 months showed an increase in the body temperature, which is accompanied by memory impairment and an enhancement of amyloid-β peptides (Aβ) generation through the upregulation of β-site APP cleaving enzyme 1 (BACE1) level and decrease in the level of an Aβ-degrading enzyme, neprilysin (NEP) in the brain, compared with those of Tg2576 mice at 23 °C. High body temperature also increased the levels of heat shock proteins (HSPs), stress-stimulated kinases such as JNK, and total tau, leading to the enhancement of tau phosphorylation at 30 °C. Taken together, our findings suggest that high body temperature exacerbates cognitive function and AD pathologies, which provides a mechanistic insight for its prevention. Show less

Apigenin is a flavonoid with antioxidant and anticancer effects. It has been reported that apigenin inhibits proliferation, migration, and invasion and induces apoptosis in cultured lung cancer cells. However, there is little information on the involvement of microRNAs (miRNAs) in its effects. miRNA microarray analysis and polymerase-chain-reaction analysis of miRNAs revealed that treatment of human lung cancer A549 cells with apigenin up-regulated the level of miR-34a-5p. Furthermore, mRNA microarray analysis and the results of three microRNA target prediction tools showed that Snail Family Transcriptional Repressor 1 (SNAI1), which inhibits the induction of apoptosis, had its mRNA expression down-regulated in A549 cells treated with apigenin. Our findings suggest that apigenin might induce apoptosis by down-regulation of SNAI1 through up-regulation of miR-34a-5p in A549 cells. Show less

Our previous studies suggested that oral administration of lipopolysaccharide (LPS) regulates the progression of various diseases via transformation of tissue-resident macrophages (MΦ). Recently, we characterized microglia transformed by repetitive low-dose LPS treatment (REPELL-microglia) in vitro, and this response was similar to that observed in response to oral administration of LPS in vivo. Here, we examined the characteristics of peritoneal tissue-resident MΦ (pMΦ) transformed by repetitive low-dose LPS treatment (REPELL-pMΦ). Primary pMΦ were treated with low-dose LPS (1 ng/ml) three times; subsequently, phagocytic activity and gene expression were evaluated. REPELL-pMΦ exhibited high phagocytic activity and elevated expression of Arg1, Gipr, Gdnf, and Fpr2. The gene expression profiles observed in REPELL-pMΦ were distinct from those of REPELL-microglia. REPELL-pMΦ have the potential to promote clearance of xenobiotics and to suppress inflammation. The present study also demonstrates the diversity of tissue-resident MΦ transformation that reflect their tissue origin. Show less

Although lipopolysaccharide (LPS) is regarded as an inducer of inflammation, previous studies have suggested that repetitive low-dose LPS has neuroprotective effects via immunomodulation of microglia, resident macrophages of brain. However, microglia transformed by the stimulus of repetitive low-dose LPS (REPELL-microglia) are not well characterized, whereas microglia transformed by repetitive high-dose LPS are well studied as an endotoxin tolerance model in which the induction of pro-inflammatory molecules is suppressed. In this study, to characterize REPELL-microglia, the gene expression and phagocytic activity of REPELL-microglia were analyzed with the murine C8-B4 microglia cell line. The REPELL-microglia were characterized by a high expression of pro-inflammatory molecules (Nos2, Ccl1, IL-12B, and CD86), anti-inflammatory molecules (IL-10, Arg1, Il13ra2, and Mrc1), and neuroprotective molecules (Ntf5, Ccl7, and Gipr). In addition, the phagocytic activity of REPELL-microglia was promoted as high as that of microglia transformed by single low-dose LPS. These results suggest the potential of REPELL-microglia for inflammatory regulation, neuroprotection, and phagocytic clearance. Moreover, this study revealed that gene expression of REPELL-microglia was distinct from that of microglia transformed by repetitive high-dose LPS treatment, suggesting the diversity of microglia transformation by different doses of LPS. Show less

Nonalcoholic steatohepatitis (NASH) is a hepatic phenotype of the metabolic syndrome, and increases the risk of cirrhosis and hepatocellular carcinoma (HCC). Although increasing evidence points to the therapeutic implications of certain types of anti-diabetic agents in NASH, it remains to be elucidated whether their effects on NASH are independent of their effects on diabetes. Genetically obese melanocortin 4 receptor-deficient (MC4R-KO) mice fed Western diet are a murine model that sequentially develops hepatic steatosis, NASH, and HCC in the presence of obesity and insulin resistance. In this study, we investigated the effect of the dipeptidyl peptidase-4 (DPP-4) inhibitor anagliptin on NASH and HCC development in MC4R-KO mice. Anagliptin treatment effectively prevented inflammation, fibrosis, and carcinogenesis in the liver of MC4R-KO mice. Interestingly, anagliptin only marginally affected body weight, systemic glucose and lipid metabolism, and hepatic steatosis. Histological data and gene expression analysis suggest that anagliptin treatment targets macrophage activation in the liver during the progression from simple steatosis to NASH. As a molecular mechanism underlying anagliptin action, we showed that glucagon-like peptide-1 suppressed proinflammatory and profibrotic phenotypes of macrophages in vitro. This study highlights the glucose metabolism-independent effects of anagliptin on NASH and HCC development. Show less

We previously reported that the patients with cholesteryl ester transfer protein (CETP) deficiency (CETP-D) show marked changes in the size and lipid compositions of high-density lipoprotein (HDL) and that they are not protected from atherosclerotic cardiovascular diseases, despite increased serum HDL-cholesterol (HDL-C) levels. HDL particles carry a variety of proteins, some of which are known to have antiatherogenic functions. This study aimed to investigate the protein composition of HDL particles in patients with CETP-D. Eight patients with complete deficiency of CETP and 8 normolipidemic healthy subjects were enrolled. We performed shotgun proteomic analysis to investigate the proteome of ultracentrifugally isolated HDL. We identified 79 HDL-associated proteins involved in lipid metabolism, protease inhibition, complement regulation, and acute-phase response, including 5 potential newly identified HDL-associated proteins such as angiopoietin-like3 (ANGPTL3). Spectral counts of apolipoprotein (apo) E were increased in patients with CETP-D compared with controls (60.3 ± 6.9 vs 43.7 ± 2.5, P < .001), which is concordant with our previous report. Complement regulatory proteins such as C3, C4a, C4b, and C9 were also significantly enriched in HDL from patients with CETP-D. Furthermore, apoC-III and ANGPTL3, both of which are now known to associate with increased atherosclerotic cardiovascular diseases, were enriched in patients with CETP-D compared with normolipidemic subjects (35.9 ± 5.3 vs 27.1 ± 3.7, 2.3 ± 1.1 vs 0.4 ± 1.1, respectively; P < .01). We have characterized HDL-associated proteins in patients with CETP-D. We identified a significant increase in the amount of apoE, apoC-III, ANGPTL3, and complement regulatory proteins. These proteomic changes might be partly responsible for the enhanced atherogenicity of patients with CETP-D. Show less

Fasting and postprandial hypertriglyceridemia (PHTG) are caused by the accumulation of triglyceride (TG)-rich lipoproteins and their remnants, which have atherogenic effects. Fibrates can improve fasting and PHTG; however, reduction of remnants is clinically needed to improve health outcomes. In the current study, we investigated the effects of a novel selective peroxisome proliferator-activated receptor α modulator (SPPARMα), K-877 (Pemafibrate), on PHTG and remnant metabolism. Male C57BL/6J mice were fed a high-fat diet (HFD) only, or an HFD containing 0.0005% K-877 or 0.05% fenofibrate, from 8 to 12 weeks of age. After 4 weeks of feeding, we measured plasma levels of TG, free fatty acids (FFA), total cholesterol (TC), HDL-C, and apolipoprotein (apo) B-48/B-100 during fasting and after oral fat loading (OFL). Plasma lipoprotein profiles after OFL, which were assessed by high performance liquid chromatography (HPLC), and fasting lipoprotein lipase (LPL) activity were compared among the groups. Both K-877 and fenofibrate suppressed body weight gain and fasting and postprandial TG levels and enhanced LPL activity in mice fed an HFD. As determined by HPLC, K-877 and fenofibrate significantly decreased the abundance of TG-rich lipoproteins, including remnants, in postprandial plasma. Both K-877 and fenofibrate decreased intestinal mRNA expression of ApoB and Npc1l1; however, hepatic expression of Srebp1c and Mttp was increased by fenofibrate but not by K-877.Hepatic mRNA expression of apoC-3 was decreased by K-877 but not by fenofibrate. K-877 may attenuate PHTG by suppressing the postprandial increase of chylomicrons and the accumulation of chylomicron remnants more effectively than fenofibrate. Show less

The cholesteryl ester transfer protein (CETP) system moves cholesteryl esters (CE) from high density lipoproteins (HDL) to lower density lipoproteins, i.e. very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) in exchange for triglycerides (TGs). This shuttle process will ultimately form complexes facilitating a bidirectional exchange of CE and TGs, the end process being CE delivery to catabolic sites. The CETP system is generally characteristic of higher animal species; lower species, not provided with this system, have higher and enlarged HDL enriched with apo E, suitable for tissue receptor interaction. Discovery of the CETP system has led to the development of agents interfering with CETP, thus elevating HDL-C and potentially preventing cardiovascular (CV) disease. Activation of CETP leads instead to reduced HDL-C levels, but also to an enhanced removal of CE from tissues. CETP antagonists are mainly small molecules (torcetrapib, anacetrapib, evacetrapib, dalcetrapib) and have provided convincing evidence of a HDL-C raising activity, but disappointing results in trials of CV prevention. In contrast, the CETP agonist probucol leads to HDL-C lowering followed by an increment of tissue cholesterol removal (reduction of xanthomas, xanthelasmas) and positive findings in secondary prevention trials. The drug has an impressive anti-inflammatory profile (markedly reduced interleukin-1β expression). Newer agents, some of natural origin, have additional valuable pharmacodynamic properties. The pharmacological approach to the CETP system remains enigmatic, although the failure of CETP antagonists has dampened enthusiasm. Studies on the system, a crossroad for any investigation on cholesterol metabolism, have however provided crucial contributions and will still be confronting any scientist working on CV prevention. Show less

We previously reported that patients with cholesteryl ester transfer protein (CETP) deficiency (CETP-D) have a higher prevalence of atherosclerotic cardiovascular disease, in spite of increased HDL-C levels. However, characterization of HDL in CETP-D has not been well described. Therefore, we examined HDL particle number (PN) rather than HDL-C level. Nine patients with CETP-D and 9 normolipidemic subjects were enrolled. We performed gel permeation high-performance liquid chromatography (GP-HPLC) analysis, determined the cholesterol and triglyceride composition of all lipoprotein subclasses, and calculated the PN of each subclass, which consisted of 3 VLDL (large, medium, and small), 4 LDL (large, medium, small, and very small), and 5 HDL (very large, large, medium, small, and very small) subclasses. The PNs of large and medium LDL were significantly lower in CETP-D than that in healthy subjects (0.66- and 0.63-fold decrease, respectively; p<0.001), whereas the PN of very small LDL, which is known to be atherogenic, was significantly higher (1.36-fold increase, p = 0.016). The PNs of very large and large HDL in CETP-D were markedly higher than that in healthy subjects (19.9- and 4.5-fold increase, respectively; p<0.001), whereas the PNs of small and very small HDL, which have more potent anti-atherogenic functions, were significantly lower (0.76- and 0.61-fold decrease, respectively; p<0.001). We have assessed the PNs of detailed subclasses of patients with CETP-D for the first time. The PN of larger HDL was markedly increased, that of smaller HDL was decreased, and that of very small LDL was increased, suggesting that CETP-D has pro-atherogenic lipoprotein properties. Show less

Epigenetic regulation is required to ensure the precise spatial and temporal pattern of gene expression that is necessary for embryonic development. Although the roles of some epigenetic modifications in embryonic development have been investigated in depth, the role of methylation at lysine 79 (H3K79me) is poorly understood. Dot1L, a unique methyltransferase for H3K79, forms complexes with distinct sets of co-factors. To further understand the role of H3K79me in embryogenesis, we generated a mouse knockout of Mllt10, the gene encoding Af10, one Dot1L complex co-factor. We find homozygous Mllt10 knockout mutants (Mllt10-KO) exhibit midline facial cleft. The midfacial defects of Mllt10-KO embryos correspond to hyperterolism and are associated with reduced proliferation of mesenchyme in developing nasal processes and adjacent tissue. We demonstrate that H3K79me level is significantly decreased in nasal processes of Mllt10-KO embryos. Importantly, we find that expression of AP2α, a gene critical for midfacial development, is directly regulated by Af10-dependent H3K79me, and expression AP2α is reduced specifically in nasal processes of Mllt10-KO embryos. Suppression of H3K79me completely mimicked the Mllt10-KO phenotype. Together these data are the first to demonstrate that Af10-dependent H3K79me is essential for development of nasal processes and adjacent tissues, and consequent midfacial formation. Show less

Cellular mechanisms that mediate steatohepatitis, an increasingly prevalent condition in the Western world for which no therapies are available, are poorly understood. Despite the fact that its synthetic agonists induce fatty liver, the liver X receptor (LXR) transcription factor remains a target of interest because of its anti-atherogenic, cholesterol removal, and anti-inflammatory activities. Here we show that tetratricopeptide repeat domain protein 39B (Ttc39b, C9orf52) (T39), a high-density lipoprotein gene discovered in human genome-wide association studies, promotes the ubiquitination and degradation of LXR. Chow-fed mice lacking T39 (T39(-/-)) display increased high-density lipoprotein cholesterol levels associated with increased enterocyte ATP-binding cassette transporter A1 (Abca1) expression and increased LXR protein without change in LXR messenger RNA. When challenged with a high fat/high cholesterol/bile salt diet, T39(-/-) mice or mice with hepatocyte-specific T39 deficiency show increased hepatic LXR protein and target gene expression, and unexpectedly protection from steatohepatitis and death. Mice fed a Western-type diet and lacking low-density lipoprotein receptor (Ldlr(-/-)T39(-/-)) show decreased fatty liver, increased high-density lipoprotein, decreased low-density lipoprotein, and reduced atherosclerosis. In addition to increasing hepatic Abcg5/8 expression and limiting dietary cholesterol absorption, T39 deficiency inhibits hepatic sterol regulatory element-binding protein 1 (SREBP-1, ADD1) processing. This is explained by an increase in microsomal phospholipids containing polyunsaturated fatty acids, linked to an LXRα-dependent increase in expression of enzymes mediating phosphatidylcholine biosynthesis and incorporation of polyunsaturated fatty acids into phospholipids. The preservation of endogenous LXR protein activates a beneficial profile of gene expression that promotes cholesterol removal and inhibits lipogenesis. T39 inhibition could be an effective strategy for reducing both steatohepatitis and atherosclerosis. Show less

The establishment of neuronal polarity is necessary for proper neuronal wiring. Semaphorin3A (Sema3A), originally identified as a repulsive axon guidance molecule, exerts a wide variety of biological functions through signaling pathways including sequential phosphorylation of collapsin response mediator protein by cyclin-dependent kinase-5 (Cdk5) and glycogen synthase kinase-3β (GSK3β). Sema3A acts on its receptor neuropilin-1 to regulate axonal transport. To delineate mechanism by which Sema3A induces axonal transport, we investigate whether GSK3β is involved in mediating Sema3A-induced axonal transport. 4-Benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione, an inhibitor of GSK3β, suppressed Sema3A-induced antero- and retrograde axonal transport. Introduction of either GSK3β mutants, GSK3β-L128A or K85M, suppressed Sema3A-induced axonal transport. On the other hand, introduction of GSK3β-R96A did not affect the Sema3A effect, suggesting that unprimed substrates are primarily involved in Sema3A-induced axonal transport. Overexpression of a partial fragment of frequently rearranged in advanced T-cell lymphomas 1 (FRATtide), which interferes the interaction between GSK3β and Axis inhibitor-1 (Axin-1), also suppressed Sema3A-induced transport. siRNA knockdown of Axin-1, an unprimed substrate of GSK3β, suppressed Sema3A-induced antero- and retrograde axonal transport. These results indicate that GSK3β and Axin-1 are involved in Sema3A-induced bidirectional axonal transport. This finding should provide a clue for understanding of mechanisms of a wide variety of biological activities of Sema3A. Show less

A high prevalence of a low glomerular filtration rate (GFR) has recently been reported in patients with diabetes without albuminuria. We aimed to clarify the clinical characteristics of such patients, including the associations between these characteristics and atherosclerosis. We investigated the correlations between the estimated GFR (eGFR) and lipid profiles, the ankle-brachial index (ABI) and the intima-media thickness (IMT) in 450 patients with type 2 diabetes without macroalbuminuria. The prevalence of renal insufficiency (RI) (GFR ＜60 mL/min/1.73 m(2)) in the patients without albuminuria was 19.1%. The ABI values of the patients with RI were significantly lower than those of the patients without RI, regardless of the presence of microalbuminuria, while there were no significant differences in IMT between the patients with and without RI. In a multivariate analysis, a low ABI was found to be significantly associated with a low eGFR, independent of age, sex, smoking, history of hypertension and/or dyslipidemia and duration of diabetes (β=0.134, p=0.013), whereas no significant associations were observed between the ABI and the urinary albumin excretion rate (UAER). The ApoB/LDL-C ratios and levels of ApoC3 were significantly higher in the patients with RI than those observed in the patients without RI, regardless of the presence of albuminuria. RI without albuminuria is closely associated with atherosclerosis of the peripheral arteries in diabetic patients. Furthermore, alterations in lipid metabolism may underlie this association. Show less

Endosomal signature phospholipid bis(monoacylglycero)phosphate (BMP) has been involved in the regulation of cellular cholesterol homeostasis. Accumulation of BMP is a hallmark of lipid storage disorders and was recently reported as a noticeable feature of oxidized low-density lipoprotein-laden macrophages. This study was designed to delineate the consequences of macrophage BMP accumulation on intracellular cholesterol distribution, metabolism, and efflux and to unravel the underlying molecular mechanisms. We have developed an experimental design to specifically increase BMP content in RAW 264.7 macrophages. After BMP accumulation, cell cholesterol distribution was markedly altered, despite no change in low-density lipoprotein uptake and hydrolysis, cholesterol esterification, or total cell cholesterol content. The expression of cholesterol-regulated genes sterol regulatory element-binding protein 2 and hydroxymethylglutaryl-coenzyme A reductase was decreased by 40%, indicative of an increase of endoplasmic reticulum-associated cholesterol. Cholesterol delivery to plasma membrane was reduced as evidenced by the 20% decrease of efflux by cyclodextrin. Functionally, BMP accumulation reduced cholesterol efflux to both apolipoprotein A1 and high-density lipoprotein by 40% and correlated with a 40% decrease in mRNA contents of ATP-binding cassette transporter A1, ATP-binding cassette transporter G1, and liver-X receptor α and β. Foam cell formation induced by oxidized low-density lipoprotein exposure was exacerbated in BMP-enriched cells. The present work shows for the first time a strong functional link between BMP and cholesterol-regulating genes involved in both intracellular metabolism and efflux. We propose that accumulation of cellular BMP might contribute to the deregulation of cholesterol homeostasis in atheromatous macrophages. Show less