👤 Hiroshi Ogura

MN-001 (tipelukast), a compound with lipid-modulating and anti-inflammatory properties, and its active metabolite MN-002, have been suggested to influence cholesterol metabolism. This study aimed to investigate whether MN-001 and MN-002 enhance cholesterol efflux via ABCA1 and ABCG1, thereby reducing foam cell formation. We also evaluated cholesterol efflux capacity in patients with diabetes before and after MN-001 administration. Cholesterol efflux was assessed in THP-1 macrophages treated with MN-001 and MN-002 in the presence of ApoA-I or HDL. ABCA1 and ABCG1 expression were evaluated using western blot and qPCR analyses. A 12-week observational study in patients with diabetes evaluated the cholesterol efflux capacity using ApoB-depleted serum and radiolabeled J774.1 macrophages. Molecular docking simulations were conducted to explore MN-002 binding affinities, aiming to identify potential target proteins and elucidate the molecular mechanisms underlying their effects on cholesterol metabolism. MN-002 enhanced ABCA1-mediated cholesterol efflux and upregulated ABCA1 expression independently of PKA. It also increased ABCG1 expression; however, neither MN-001 nor MN-002 influenced HDL-mediated efflux. MN-001 showed no significant improvement in cholesterol efflux capacity (p = 0.6507) in patients with diabetes. Molecular docking simulations indicated that MN-002 may bind to PPAR-alpha, suggesting a potential mechanism for its effects. MN-002 offers a novel therapeutic approach for atherosclerosis by upregulating ABCA1 and ABCG1 expression and enhancing ApoA-I-mediated cholesterol efflux. Further studies are required to clarify the underlying mechanisms and assess their clinical potential in atherosclerosis and metabolic disorders. Show less

Familial hypercholesterolemia (FH) causes corneal arcus (CA) and xanthomas via lipid particle deposition. Lipoprotein(a) [Lp(a)] consists of an apolipoproteinB100 and apolipoprotein(a). As apolipoprotein(a) accumulates within extracellular connective tissues, it may associate with CA and tendon xanthoma. To elucidate the association between elevated Lp(a) and FH-related physical features and evaluate their independent and joint prognostic utility on cardiovascular risk. We retrospectively analyzed 484 clinically diagnosed FH patients, evaluating both Lp(a) and physical features. Physical features were compared in individuals with and without Lp(a) ≥ 30 mg/dL. The occurrence of major adverse cardiovascular events (MACE = cardiovascular death + acute coronary syndrome + ischemic stroke) was compared in those stratified according to Lp(a) ≥ 30 mg/dL and physical features. The median value of Lp(a) was 18.4 mg/dL; subjects with Lp(a) ≥ 30 mg/dL were more likely to exhibit CA and greater Achilles tendon thickness (ATT). Receiver operating characteristic analysis suggested 14.0 mm as an optimal cut-off value of ATT predicting Lp(a) ≥ 30 mg/dL (C-statistic = 0.58). Even after adjusting for age, sex, untreated low-density lipoprotein cholesterol level, and FH-related pathogenic variants, the co-existence of CA and ATT ≥ 14.0 mm was independently associated with Lp(a) ≥30 mg/dL (odds ratio = 2.31; 95% CI = 1.22-4.38; P = .010). During a 15-year observational period (median = 1835 days), MACE occurred more frequently in subjects with Lp(a) ≥ 30 mg/dL (log-rank P = .026). This Lp(a)-associated cardiovascular risk was further elevated among those with both CA and ATT ≥ 14.0 mm (log-rank P = .042), whereas the presence of physical stigmata did not worsen cardiovascular outcome when Lp(a) was < 30 mg/dL. Assessment of CA and ATT in FH identifies those more likely to have higher Lp(a) levels. The presence of these triads is associated with the highest risk of MACE and potentially guides intensification of antiatherosclerotic therapies. Show less

To support in vivo and in vitro studies of intravascular triglyceride metabolism in mice, we created rat monoclonal antibodies (mAbs) against mouse LPL. Two mAbs, mAbs 23A1 and 31A5, were used to develop a sandwich ELISA for mouse LPL. The detection of mouse LPL by the ELISA was linear in concentrations ranging from 0.31 ng/ml to 20 ng/ml. The sensitivity of the ELISA made it possible to quantify LPL in serum and in both pre-heparin and post-heparin plasma samples (including in grossly lipemic samples). LPL mass and activity levels in the post-heparin plasma were lower in Gpihbp1 Show less

Neoatherosclerosis (NA), which refers to neointimal atherosclerosis within a stent, is considered one of the underlying causes of late-phase stent failure following a newer generation drug-eluting stent (DES) placement procedure. Even contemporary guideline-directed medical therapy may be insufficient to prevent NA. This study aimed to investigate how intricately lipid markers are associated with NA formation in the early phase of treatment with well-maintained low-density lipoprotein cholesterol (LDL-C) levels. We enrolled 114 consecutive patients undergoing statin treatment and percutaneous coronary intervention (PCI) with current-generation DES for coronary artery disease. At a median 12 months after PCI, optical coherence tomography (OCT) was performed. Various lipid markers, including LDL-C, triglyceride (TG), triglyceride-rich lipoprotein cholesterol (TRL-C), non-high-density lipoprotein cholesterol (non-HDL-C), malondialdehyde-modified LDL (MDA-LDL), and several apolipoproteins, were also evaluated. NA was observed in 17 (14.9%) patients. The LDL-C level was equivalent in patients with or without NA (77.2 vs. 69.8 mg/dL; p=0.15). However, the levels of TG, apolipoprotein C3 (apoC3), TRL-C, non-HDL-C, and apolipoprotein B (apoB), and MDA-LDL were significantly higher in the patients with NA. Furthermore, multivariate logistic regression adjusting for HbA1c and stent duration revealed apoC3, TRL-C, non-HDL-C, apoB, and MDA-LDL levels as risk factors for NA. However, when apoB was included as a covariate, other factors became nonsignificant. Abnormal triglyceride-rich lipoprotein metabolism and high atherogenic apoB-containing lipoprotein particle numbers are associated with the formation of NA in patients undergoing statin treatment at a median 12 months post-PCI. Show less

We evaluated mRNA and miRNA in COVID-19 patients and elucidated the pathogenesis of COVID-19, including protein profiles, following mRNA and miRNA integration analysis. mRNA and miRNA sequencing was done on admission with whole blood of 5 and 16 healthy controls (HCs) and 10 and 31 critically ill COVID-19 patients (derivation and validation cohorts, respectively). Interferon (IFN)-α2, IFN-β, IFN-γ, interleukin-27, and IFN-λ1 were measured in COVID-19 patients on admission (day 1, 181 critical/22 non-critical patients) and days 6-8 (168 critical patients) and in 19 HCs. In the derivation cohort, 3,488 mRNA and 31 miRNA expressions were identified among differentially expressed RNA expressions in the patients versus those in HCs, and 2,945 mRNA and 32 miRNA expressions in the validation cohort. Canonical pathway analysis showed the IFN signaling pathway to be most activated. The IFN-β plasma level was elevated in line with increased severity compared with HCs, as were IFN-β downstream proteins, such as interleukin-27. IFN-λ1 was higher in non-critically ill patients versus HCs but lower in critical than non-critical patients. Integration of mRNA and miRNA analysis showed activated IFN signaling. Plasma IFN protein profile revealed that IFN-β (type I) and IFN-λ1 (type III) played important roles in COVID-19 disease progression. Show less

Primary chylomicronemia (PCM) is a rare and intractable disease characterized by marked accumulation of chylomicrons in plasma. The levels of plasma triglycerides (TGs) typically range from 1,000 - 15,000 mg/dL or higher.PCM is caused by defects in the lipoprotein lipase (LPL) pathway due to genetic mutations, autoantibodies, or unidentified causes. The monogenic type is typically inherited as an autosomal recessive trait with loss-of-function mutations in LPL pathway genes (LPL, LMF1, GPIHBP1, APOC2, and APOA5). Secondary/environmental factors (diabetes, alcohol intake, pregnancy, etc.) often exacerbate hypertriglyceridemia (HTG). The signs, symptoms, and complications of chylomicronemia include eruptive xanthomas, lipemia retinalis, hepatosplenomegaly, and acute pancreatitis with onset as early as in infancy. Acute pancreatitis can be fatal and recurrent episodes of abdominal pain may lead to dietary fat intolerance and failure to thrive.The main goal of treatment is to prevent acute pancreatitis by reducing plasma TG levels to at least less than 500-1,000 mg/dL. However, current TG-lowering medications are generally ineffective for PCM. The only other treatment options are modulation of secondary/environmental factors. Most patients need strict dietary fat restriction, which is often difficult to maintain and likely affects their quality of life.Timely diagnosis is critical for the best prognosis with currently available management, but PCM is often misdiagnosed and undertreated. The aim of this review is firstly to summarize the pathogenesis, signs, symptoms, diagnosis, and management of PCM, and secondly to propose simple diagnostic criteria that can be readily translated into general clinical practice to improve the diagnostic rate of PCM. In fact, these criteria are currently used to define eligibility to receive social support from the Japanese government for PCM as a rare and intractable disease.Nevertheless, further research to unravel the molecular pathogenesis and develop effective therapeutic modalities is warranted. Nationwide registry research on PCM is currently ongoing in Japan with the aim of better understanding the disease burden as well as the unmet needs of this life-threatening disease with poor therapeutic options. Show less

This study investigated whether the small dense low-density lipoprotein cholesterol (sd-LDL-c) level is associated with the rapid progression (RP) of non-culprit coronary artery lesions and cardiovascular events (CE) after acute coronary syndrome (ACS). In 142 consecutive patients with ACS who underwent primary percutaneous coronary intervention for the culprit lesion, the sd-LDL-c level was measured using a direct homogeneous assay on admission for ACS and at the 10-month follow-up coronary angiography. RP was defined as a progression of any pre-existing coronary stenosis and/or stenosis development in the initially normal coronary artery. CEs were defined as cardiac death, myocardial infarction, stroke, or coronary revascularization. Patients were divided into two groups based on the presence (n=29) or absence (n=113) of RP after 10 months. The LDL-c and sd-LDL-c levels at baseline were equivalent in both the groups. However, the sd-LDL-c, triglyceride, remnant lipoprotein cholesterol (RL-c), and apoC3 levels at follow-up were significantly higher in the RP group than in the non-RP group. The optimal threshold values of sd-LDL-c, triglyceride, RL-c, and apoC3 for predicting RP according to receiver operating characteristics analysis were 20.9, 113, 5.5, and 9.7 mg/dL, respectively. Only the sd-LDL-c level (≥ 20.9 mg/dL) was significantly associated with incident CEs at 31±17 months (log-rank: 4.123, p=0.043). The sd-LDL-c level on treatment was significantly associated with RP of non-culprit lesions, resulting in CEs in ACS patients. On-treatment sd-LDL-c is a residual risk and aggressive reduction of sd-LDL-c might be needed to prevent CEs. Show less

In diabetes mellitus (DM) patients, the morbidity of infectious disease is increased, and these infections can easily progress from local to systemic infection. Sepsis is a characteristic of organ failure related to microcirculation disorders resulting from endothelial cell injury, whose most frequent comorbidity in patients is DM. The aim of the present study was to evaluate the influence of infection on DM-induced microvascular damage on inflammation and pulmonary endothelial structure using an experimental endotoxemia model. Lipopolysaccharide (LPS; 15 mg/kg) was injected intraperitoneally into 10-week-old male C57BLKS/J Iar Show less

We investigated lipid metabolism in PXB-cells, which are human primary hepatocytes isolated from liver-humanized mice, and HepG2 and HuH-7 human hepatoma cell lines. Lipoprotein levels were higher in PXB-cells than in the 2 other cell lines, and PXB-cells mainly released triglycerides and cholesterol as very low density lipoprotein (VLDL), similar to actual liver tissue, whereas the major lipoprotein released from the 2 hepatoma cell lines was LDL. RT-PCR analysis demonstrated that the gene expression levels of apolipoprotein B100 (ApoB100), the apolipoprotein of VLDL/LDL, were similar in PXB-cells and HepG2 cells, while the overexpression of ApoC2, ApoC3, and ApoE, which are components of VLDL, but not LDL, was observed in PXBcells. A protein immunoassay revealed that ApoB100 levels secreted from PXB-cells and HuH-7 cells were similar; however, ApoC3 levels were higher in PXB-cells than in the two other cell lines. We also examined the anti-lipidemic activities of fenofibrate using this assay system. Fenofibrate suppressed lipoprotein production from PXB-cells in a dose-dependent manner mainly by activating the β-oxidation pathway. These results suggest that PXB-cells produce high levels of lipoproteins and are suitable for screening anti-lipidemic agents. Show less

Development of multi-chambered heart is associated with spatio-temporal regulation of gene expression. A basic helix-loop-helix transcription factor Hey2 is specifically expressed in the embryonic mouse ventricles and is indispensable for ventricular myocyte differentiation, compartment identity and morphogenesis of the heart. However, how Hey2 transcription is precisely regulated in the heart remains unclear. In this study, we identified a distal Hey2 enhancer conserved in the mouse and human to possess specific transcriptional activity in ventricular free wall myocytes at the looping stage of cardiac development. Deletion of the enhancer significantly decreased endogenous Hey2 expression in the ventricular myocardium but not in other tissues of mouse embryos. Mutation/deletion of the conserved binding sites for T-box and Gata proteins, but not NK-2 proteins, abolished the enhancer activity, and Tbx20 null mice completely lost the enhancer activity in the embryonic ventricles. Luciferase reporter analysis suggested that the ventricular enhancer activity was controlled by Tbx20 through its DNA binding and cooperative function with cardiac Gata proteins. These results delineate a regulatory mechanism of ventricular Hey2 expression and help fully understand molecular cascades in myocardial cell differentiation and cardiac morphogenesis during embryonic development. Show less

Peritoneal fibrosis (PF) is a severe complication of peritoneal dialysis, but there are few effective therapies for it. Recent studies have revealed a new biological function of trehalose as an autophagy inducer. Thus far, there are few reports regarding the therapeutic effects of trehalose on fibrotic diseases. Therefore, we examined whether trehalose has anti-fibrotic effects on PF. PF was induced by intraperitoneal injection of chlorhexidine gluconate (CG). CG challenges induced the increase of peritoneal thickness, ColIα Show less

Xanthohumol, a prominent prenyl flavonoid from the hop plant (Humulus lupulus L.), is suggested to be antiatherogenic since it reportedly increases high-density lipoprotein (HDL) cholesterol levels. It is not clear whether xanthohumol promotes reverse cholesterol transport (RCT), the most important antiatherogenic property of HDL; therefore, we investigated the effects of xanthohumol on macrophage-to-feces RCT using a hamster model as a CETP-expressing species. In vivo RCT experiments showed that xanthohumol significantly increased fecal appearance of the tracer derived from intraperitoneally injected [ Show less

We here report the first case of discordant Pena-Shokeir phenotype observed in monoamniotic twins. A 34-year-old woman, pregnant with twins, was referred at 10 weeks' gestation because one of the twins had increased nuchal translucency. Serial ultrasonographic examinations suggested that twin A may have had several other abnormalities, including pleural effusion at 21 weeks' gestation, decreased movement and contracted limbs at 24 weeks, and fetal growth restriction at 26 weeks. No abnormalities were observed in twin B. At 34 weeks of gestation, the twins were delivered by cesarean section. There were cord entanglements, and although the resuscitation of twin A was attempted, it proved difficult due to lockjaw. Twin A died during the second hour of life, and autopsy findings were consistent with the diagnosis of Pena-Shokeir phenotype. We suggest that cord entanglement during early gestation is a possible cause for the occurrence of Pena-Shokeir phenotype through an anoxic-ischemic mechanism. Show less

Multidrug resistance protein 2 (MRP2, ABCC2) is localized to the apical membrane of hepatocytes and played an important role in the biliary excretion of a broad range of endogenous and xenobiotic compounds and drugs, such as pravastatin. However, the effects of statins on MRP2 in the liver and the precise mechanisms of their actions have been obscure. The goal of this study was to determine the regulatory molecular mechanism for statin-induced MRP2 expression in hepatocytes. In vitro and in vivo studies suggested that pitavastatin increased MRP2 expression. Pitavastatin promoted liver X receptor (LXR) α/β translocation from the cytosol to nuclei, resulting in LXR activation. Deletion and mutational analysis suggested that the potential sterol regulatory element (SRE) played a major role in the observed modulation of MRP2 expression by pitavastatin. Furthermore pitavastatin increased the protein-DNA complex, and when SRE was mutated, stimulation of the protein-DNA complex by pitavastatin was decreased. It was demonstrated that pitavastatin upregulated MRP2 expression by an SREBP regulatory pathway in hepatocytes and that the actions of statins may lead to improve the biliary excretion of MRP2 substrates. Show less

Pioglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) agonist, reportedly reduces cardiovascular events in diabetic patients. ATP cassette binding transporters (ABC) A1 and G1 are pivotal molecules for cholesterol efflux (ChE) from macrophages and high density-lipoprotein biogenesis, and the A1 transporter is regulated by a PPARγ-liver receptor X (LXR) pathway. Also, pioglitazone induces ABCG1 expression, though the exact mechanism remains unclear. We therefore investigated the effects of pioglitazone on ABCA1/G1 expression in vitro and ex vivo. The effects of pioglitazone on ChE and ABCA1/G1 expressions in macrophages were assessed. Then, mRNA was quantified in macrophages when PPARγ/LXR inhibition by siRNA or overexpression of oxysterol sulfotransferase was performed. ABCA1/G1 promoter activity with mutated LXR-responsive elements was also measured. As an ex vivo study, 15 type 2 diabetic patients were administered pioglitazone or placebo, and ChE assays and protein expressions were determined using macrophages cultured with the corresponding sera. Pioglitazone increased LXRα/ABCA1/G1 expressions, which enhanced ChE from macrophages. Inhibition of PPARγ/LXR pathways revealed that LXR was primarily involved in pioglitazone's transactivation of ABCA1 but only partially involved for ABCG1. Promoter assays showed that ABCG1 was regulated more by the promoter in intron 4 than that upstream of exon 1 but both promoters were responsive to LXR activation. Sera obtained after pioglitazone treatment promoted ChE and ABCA1/G1 expressions in macrophages. Pioglitazone enhanced ChE from macrophages by increasing ABCA1/G1 in LXR-dependent and -independent manners. Our comparable in vitro and ex vivo results shed new light on pioglitazone's novel anti-atherogenic property. Show less

SIR2 protein, an NAD-dependent deacetylase, is localized to nucleus and is involved in life span extension by calorie restriction in yeast. In mammals, among the seven SIR2 homologues (SIRT1-7), SIRT3, 4, and 5 are localized to mitochondria. As SIRT5 mRNA levels in liver are increased by fasting, the physiological role of SIRT5 was investigated in liver of SIRT5-overexpressing transgenic (SIRT5 Tg) mice. We identified carbamoyl phosphate synthetase 1 (CPS1), a key enzyme of the urea cycle that catalyzes condensation of ammonia with bicarbonate to form carbamoyl phosphate, as a target of SIRT5 by two-dimensional electrophoresis comparing mitochondrial proteins in livers of SIRT5 Tg and wild-type mice. CPS1 protein was more deacetylated and activated in liver of SIRT5 Tg mice than in wild-type. In addition, urea production was upregulated in hepatocytes of SIRT5 Tg mice. These results agree with those of a previous study using SIRT5 knockout (KO) mice. Because ammonia generated during fasting is toxic, SIRT5 protein might play a protective role by converting ammonia to non-toxic urea through deacetylation and activation of CPS1. Show less

Calcium plays a fundamental role as second messenger in intracellular signaling and bone serves as the body's calcium reserve to tightly maintain blood calcium levels. Calcium in ingested meal is the main supply and inadequate calcium intake causes osteoporosis and bone fracture. Here, we describe a novel mechanism of how ingested calcium is deposited on bone. Meal ingestion elicits secretion of the gut hormone gastric inhibitory polypeptide (GIP) from endocrine K cells in the duodenum. Bone histomorphometrical analyses revealed that bone formation parameters in the mice lacking GIP receptor (GIPR(-/-)) were significantly lower than those of wild-type (GIPR(+/+)) mice, and that the number of osteoclasts, especially multinuclear osteoclasts, was significantly increased in GIPR(-/-) mice, indicating that GIPR(-/-) mice have high-turnover osteoporosis. In vitro examination showed the percentage of osteoblastic cells undergoing apoptosis to be significantly decreased in the presence of GIP. Because GIPR(-/-) mice exhibited an increased plasma calcium concentration after meal ingestion, GIP directly links calcium contained in meal to calcium deposition on bone. Show less

Atypical protein kinase C (aPKC) has been implicated in several signaling pathways such as cell polarity, cell survival, and cell differentiation. In contrast to other PKCs, aPKC is unique in having the PB1 (Phox and Bem 1) domain in the N terminus. The aPKC PB1 domain binds with ZIP/p62, Par6, or MEK5 through a PB1-PB1 domain interaction that controls the localization of aPKC. Here, we determined the three-dimensional structure of the PB1 domain of PKCiota by NMR and found that the PB1 domain adopts a ubiquitin fold. The OPCA (OPR, PC, and AID) motif inserted into the ubiquitin fold was presented as a betabetaalpha fold in which the side chains of conserved Asp residues were oriented to the same direction to form an acidic surface. This structural feature suggested that the acidic surface of the PKCiota PB1 domain interacted with the basic surface of the target PB1 domains, and this was confirmed in the case of the PKCiota-ZIP/p62 complex by mutational analysis. Interestingly, in the PKCiota PB1 domain a conserved lysine residue was located on the side opposite to the OPCA motif-presenting surface, suggesting dual roles for the PKCiota PB1 domain in that it could interact with either the conserved lysine residue or the acidic residues on the OPCA motif of the target PB1 domains. Show less