👤 Hiromichi Fujino

Cerebral deposition of fibrillar amyloid-β (Aβ) is a pathological hallmark of Alzheimer's disease. Although Aβ is present in human placentas and accumulates in preeclamptic placentas characterized by poor placentation, the production and role of Aβ in the human placenta remain unclear. Because hypoxia in mid-to-late pregnancy is a risk for preeclampsia, we found that levels of hypoxia-inducible factor 1-α and β-secretase (BACE-1) increased concurrently with placental Aβ deposition in late-stage preeclamptic placentas. We also found that a human cytotrophoblast (CTB) model, BeWo cells, actually produced Aβ species and that hypoxia increased Aβ production and BACE-1 protein levels. Aβ42 fibrils inhibited CTB syncytialization, a critical step in maintaining pregnancy, by inducing loss of membrane localization of cell-cell adhesion molecules. Primary human CTBs confirmed these observations. Taken together, our results suggest that increased Aβ production in CTBs by hypoxia may lead to the formation of Aβ fibrils, which inhibit syncytiotrophoblast formation and are detrimental to pregnancy. Thus, our results reveal the novel role of Aβ fibrils in the pathogenesis of preeclampsia. Show less

Type 2 diabetic patients exhibited an increased secretion of triglyceride-rich lipoproteins and low high-density lipoprotein cholesterol levels with a greater amount of small dense low-density lipoprotein (LDL). Given that apolipoprotein B (apoB), a proatherogenic lipoprotein, exists at both triglyceride-rich lipoproteins and LDL particles, circulating apoB may associate with diabetic coronary atherosclerosis. The OPTIMAL study was a prospective randomized-controlled study which employed serial near-infrared spectroscopy (NIRS)/intravascular ultrasound (IVUS) imaging to evaluate the efficacy of glycemic control on coronary atherosclerosis in 94 statin-treated type 2 diabetic patients with coronary artery disease (CAD) (UMIN000036721). Of these, 78 patients with both serial apoB levels and NIRS/IVUS images at baseline and week 48 were analyzed. NIRS/IVUS-derived plaque measures were compared in those with and without any reduction of apoB levels. All of the study subjects received a statin, and 60.6% of the study subjects exhibited any reduction of apoB levels. There was no significant difference in the atheroma progression rate between the 2 groups (-0.27 ± 0.15% vs -0.33 ± 0.51%, P = .44). However, patients with any reduction of apoB levels exhibited a greater frequency of change in maximal lipid-core burden index at 4-mm segment (maxLCBI In statin-treated type 2 diabetic patients with CAD, a greater delipidation of coronary atherosclerosis was observed in association with a reduction of apoB levels. The current findings indicate a potential anti-atherosclerotic effect of lowering apoB levels, which may ultimately mitigate future coronary events risk in statin-treated type 2 diabetic patients with CAD. Show less

Addition of the PCSK9 inhibitor, evolocumab, to statin therapy promoted coronary plaque stabilization after an acute coronary syndrome. While apolipoprotein B (ApoB) has been proposed as a goal for lipid-lowering therapy in the prevention of cardiovascular disease, its association with plaque stability has not been studied. The High-Resolution Assessment of Coronary Plaques in a Global Evolocumab Randomized Study (HUYGENS) used serial optical coherence tomography to assess coronary plaque phenotypes in patients with non-ST elevation myocardial infarction treated with evolocumab plus statin or placebo plus statin for 52 weeks. Changes in plaque composition were studied in patients according to achievement of a goal ApoB level <65 mg/dL. Of 112 patients, 67 (59.8 %) achieved the ApoB goal and had lower ApoB values at follow-up compared with those not at goal (37.1 ± 15.0 vs 92.7 ± 19.4 mg/dL, P < 0.001). Patients achieving the ApoB goal demonstrated a greater increase in minimum fibrous cap thickness (+44.6 ± 36.0 vs +24.9 ± 38.1 μm, P = 0.007) and a more pronounced decrease in lipid arc (-57.8 ± 52.8 vs -27.0 ± 59.2°, P = 0.005) at follow-up, compared with those who did not achieve the ApoB goal. At follow-up, thin-cap fibroatheroma (TCFA) was less prevalent among patients achieving the ApoB goal compared with those not at goal (9.0 vs. 40.0 %, P < 0.001). Multivariate analysis demonstrated that achieving an ApoB <65 mg/dL at follow-up independently associated with the absence of TCFA at follow-up (P = 0.004). Lower achieved ApoB levels associated with evidence of greater plaque stabilization even after controlling for low-density lipoprotein cholesterol levels. This highlights the importance of optimizing ApoB levels for the reduction of cardiovascular risk. NCT03570697. Show less

Plasmalogens are a family of glycerophospholipids containing one vinyl-ether bond at the sn-1 position in the glycerol backbone, and play important roles in cellular homeostasis including neural transmission. Therefore, reductions of plasmalogens have been associated with neurodegenerative disorders, such as Alzheimer's disease (AD). To evaluate the potential protective effects of plasmalogens against the pathology of AD, protein expression levels of key factors in amyloid precursor protein (APP) metabolic processes were examined using human neuroblastoma SH-SY5Y cells. Here, phosphatidylcholine-plasmalogen-oleic acid (PC-PLS-18) was shown to reduce protein expression levels of β-site APP cleaving enzyme 1 (BACE1), clusterin, and Tau, factors involved in the amyloid β-associated pathogenesis of AD. Thus, PC-PLS-18 may have preventive effects against AD by delaying the onset risk for a certain period. 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

Occurrence of malignant ventricular tachyarrhythmias such as ventricular tachycardia and fibrillation (VT/VF) in hypertrophic cardiomyopathy (HCM) can be related to the extent of myocardial fibrosis. Although late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging has been used to detect myocardial fibrosis, few data exist regarding relationships between CMR-determined myocardial fibrosis and VT/VF in genotyped HCM populations. We retrospectively investigated whether the extent of LGE can be increased in HCM patients with VT/VF compared to those without VT/VF in the genotyped HCM population. We studied 35 HCM patients harboring sarcomere gene mutations (TNNI3=22, MYBPC3=12, MYH7=1) who underwent both CMR imaging and 24-h ambulatory electrocardiographic monitoring. VT/VF were identified in 6 patients (2 men, mean age 55.0 years). The extent of LGE was significantly increased in patients with VT/VF (n=6) compared with those without VT/VF (n=29) (18.6±14.4% vs. 8.3±11.4%, p=0.04), although the LGE extent was not an independent predictor for the occurrence of VT/VF. Applying a cut-off point ≥3.25%, episodes of VT/VF were identified with a sensitivity of 100%, specificity of 51.7%, positive predictive value of 30%, negative predictive value of 100%, and the area under the curve of 0.767 (95% confidence interval: 0.590-0.944). These results demonstrate that myocardial fibrosis determined by CMR imaging may be increased in genotyped HCM patients with episodes of VT/VF. A further prospective study will be needed to clarify the association between the LGE extent and arrhythmic events in HCM patients harboring sarcomere gene mutations. Show less

Although most founder mutation carriers of hypertrophic cardiomyopathy (HCM), such as the cardiac myosin-binding protein C gene (MYBPC3), arose from a common ancestor exhibit favorable clinical phenotypes, there still remain small fractions of these carriers associated with increased cardiovascular events. However, few data exist regarding the defining factors that modify phenotypes of these patients, particularly in terms of multiple gene mutations. Therefore, we assessed genotype-phenotype correlations and investigated factors that contribute to phenotypic diversities of mutation carriers from 488 unrelated HCM probands. A prevalent founder mutation (Val762Asp) in MYBPC3 was identified in 33 subjects from 19 families. Among them, 28 carriers harbored an isolated Val762Asp mutation and exhibited a late onset of overt HCM compared with other MYBPC3 mutation carriers (62.8 ± 3.0 vs 50.1 ± 2.6 yr, P < 0.05). In contrast, the remaining five carriers had additional sarcomere gene mutations (3 carriers in MYBPC3 and 2 carriers in the cardiac troponin T gene). Of these five carriers, two carriers showed early disease onset and one carrier exhibited end-stage HCM. These phenotypes were recapitulated in zebrafish models; injection of MYBPC3 Val762Asp alone did not alter ventricular size or function, but ventricular dimension was significantly increased when MYBPC3 Val762Asp mRNA was coinjected with MYBPC3 Arg820Gln mRNA. These results demonstrate that MYBPC3 Val762Asp may be associated with unfavorable HCM phenotypes in some cases when combined with another MYBPC3 mutation. Show less

Hypertrophic cardiomyopathy (HCM) is a disease of the sarcomere, and approximately 5% of cases of HCM show systolic dysfunction with poor prognosis. Few data exist regarding the systolic dysfunction in a large population of genotyped HCM subjects. The aim of this study was to assess the systolic dysfunction and prognosis in sarcomere gene mutation carriers. The study included 157 sarcomere gene mutation carriers from 69 unrelated HCM families (87 males; mean age, 46.5 ± 20.5 years). After exclusions for systolic dysfunction at baseline, 107 subjects underwent serial echocardiograms. At a mean follow-up of 7.0 years, 12 subjects experienced systolic dysfunction. In multivariate Cox analysis, systolic dysfunction was related to age and ejection fraction at initial evaluation (P < 0.001 and P = 0.020, respectively), and was associated with the absence of mutations in the cardiac myosin-binding protein C gene (MYBPC3) (P = 0.042). When the subjects were divided into MYBPC3 and non-MYBPC3 mutation carriers, and time from birth to development of systolic dysfunction was compared, the rate of systolic dysfunction was higher in the non-MYBPC3 group than in MYBPC3 group (Kaplan-Meier, log-rank test, P = 0.010). After the onset of systolic dysfunction, 11 of 12 subjects died during a mean follow-up of 8.3 years. Non-MYBPC3 mutation carriers developed left ventricular systolic dysfunction more frequently than MYBPC3 mutation carriers, and the majority of sarcomere gene mutation carriers with systolic dysfunction had fatal outcomes during follow-up. This suggests that subjects with mutations in sarcomeric genes require careful management for systolic dysfunction. Show less

We previously studied fatty acid metabolism in the liver of nonalcoholic fatty liver disease (NAFLD) and reported the activation of the LXRalpha-SREBP-1c pathway in hepatocytes. LXRalpha regulates cholesterol metabolism as well as fatty acid metabolism, and its agonistic ligands are oxysterols. Moreover, there is some evidence that excess cholesterol intake is involved in the onset of NAFLD. Therefore, in this study, we examined the expression of cholesterol metabolism-associated genes in the NAFLD liver by real-time PCR. Expression of LXRalpha and ACAT1 was up-regulated in NAFLD and this was more noticeable in non-obese rather than in obese patients. Although the expression of the LDL receptor, which acts on cholesterol uptake, and of SREBP-2, a positive key regulator of cholesterol, was suppressed, the expression of enzymes that promote cholesterol synthesis was uniformly increased in NAFLD. Gene expression of apoB100 and microsomal triglyceride transfer protein, which are associated with VLDL secretion, and ABCG5, which is involved in cholesterol excretion, was significantly elevated in NAFLD. Because cholesterol accumulates in hepatocytes in NAFLD liver, cholesterol uptake and synthesis should be physiologically down-regulated. However, cholesterol synthesis was activated in NAFLD liver, meaning that cholesterol metabolism is dysregulated in NAFLD. Overproduction of cholesterol may lead to an increased level of oxysterols, activation of LXRalpha and SREBP-1c, and enhanced fatty acid synthesis. Show less

Some patients with dilated cardiomyopathy (DCM) have mutations of the genes that encode sarcomeric or cytoskeletal proteins of cardiomyocytes, but the prevalence of these mutations in Japan remains unclear. A group of 99 unrelated adult patients with DCM (familial n=27, sporadic n=72) were screened for the following genes: cardiac beta-myosin heavy chain, cardiac myosin-binding protein C (MYBPC3), regulatory and essential myosin light chains, alpha cardiac actin, alpha tropomyosin, cardiac troponin T, cardiac troponin I, cardiac troponin C, dystrophin, and lamin A/C. A mutation (R820Q) in MYBPC3 was found in an aged patient. In addition, dystrophin mutations were identified in 3 male patients (2 with exon 45-48 deletion and 1 with exon 48-52 deletion). The prevalence of dystrophin mutations in male patients with DCM was 4.4% (3 of 68). No mutations involving amino acid changes were identified in the other genes. Although cases of adult patients with DCM caused by mutations of the genes encoding sarcomeric or cytoskeletal proteins of cardiomyocytes are infrequent in Japan, it may be advisable to screen older DCM patients for MYBPC3 mutations, and male patients with familial DCM for dystrophin mutations. Show less