Professional Education

  • Doctor of Philosophy, Kyoto University (2017)
  • Cardiology fellowship, Tenri Hospital, Nara, Japan (2012)
  • Residency, Tenri Hospital, Nara, Japan (2009)
  • Doctor of Medicine, Kyoto University (2007)

Stanford Advisors


All Publications

  • Hepatokine alpha1-Microglobulin Signaling Exacerbates Inflammation and Disturbs Fibrotic Repair in Mouse Myocardial Infarction. Scientific reports Hakuno, D., Kimura, M., Ito, S., Satoh, J., Nakashima, Y., Horie, T., Kuwabara, Y., Nishiga, M., Ide, Y., Baba, O., Nishi, H., Nakao, T., Nishino, T., Nakazeki, F., Koyama, S., Hanada, R., Randolph, R. R., Endo, J., Kimura, T., Ono, K. 2018; 8 (1): 16749


    Acute cardiac rupture and adverse left ventricular (LV) remodeling causing heart failure are serious complications of acute myocardial infarction (MI). While cardio-hepatic interactions have been recognized, their role in MI remains unknown. We treated cultured cardiomyocytes with conditioned media from various cell types and analyzed the media by mass spectrometry to identify alpha1-microglobulin (AM) as an Akt-activating hepatokine. In mouse MI model, AM protein transiently distributed in the infarct and border zones during the acute phase, reflecting infiltration of AM-bound macrophages. AM stimulation activated Akt, NFkappaB, and ERK signaling and enhanced inflammation as well as macrophage migration and polarization, while inhibited fibrogenesis-related mRNA expression in cultured macrophages and cardiac fibroblasts. Intramyocardial AM administration exacerbated macrophage infiltration, inflammation, and matrix metalloproteinase 9 mRNA expression in the infarct and border zones, whereas disturbed fibrotic repair, then provoked acute cardiac rupture in MI. Shotgun proteomics and lipid pull-down analysis found that AM partly binds to phosphatidic acid (PA) for its signaling and function. Furthermore, systemic delivery of a selective inhibitor of diacylglycerol kinase alpha-mediated PA synthesis notably reduced macrophage infiltration, inflammation, matrix metalloproteinase activity, and adverse LV remodeling in MI. Therefore, targeting AM signaling could be a novel pharmacological option to mitigate adverse LV remodeling in MI.

    View details for PubMedID 30425314

  • Circulating markers of collagen types I, III, and IV in patients with dilated cardiomyopathy: relationships with myocardial collagen expression. ESC heart failure Nagao, K., Inada, T., Tamura, A., Kajitani, K., Shimamura, K., Yukawa, H., Aida, K., Sowa, N., Nishiga, M., Horie, T., Makita, T., Ono, K., Tanaka, M. 2018


    AIMS: Collagen-derived peptides such as collagen I C-terminal telopeptide (CITP) and procollagen III N-terminal propeptide (PIIINP) have been conventionally used as markers of cardiac fibrosis. Collagen IV 7S domain (P4NP 7S) has been recently reported to be correlated with haemodynamics in patients with acute heart failure. We investigated whether these markers reflect cardiac remodelling and myocardial collagen expression.METHODS AND RESULTS: In 80 patients with dilated cardiomyopathy, relationships of CITP, PIIINP, and P4NP 7S to clinical and echocardiographic variables were analysed. CITP and PIIINP were inversely correlated with estimated glomerular filtration rate (r=-0.41, P<0.001 and r=-0.32, P=0.004, respectively); P4NP 7S was positively correlated with B-type natriuretic peptide (r=0.32, P=0.003) and gamma-glutamyltransferase (r=0.38, P<0.001). These correlations were significant even after adjustment by potential confounders, whereas all three collagen markers were not independently correlated with ejection fraction nor with left ventricular (LV) diastolic diameter. In 33 patients undergoing endomyocardial biopsy, myocardial collagen I and III mRNA expressions were correlated with LV end-diastolic volume index (r=0.42, P=0.02 and r=0.54, P=0.002, respectively), whereas myocardial collagen IV mRNA expression was not correlated with LV end-diastolic volume index nor with ejection fraction. Each collagen-derived peptide was not significantly correlated with the myocardial expression of their corresponding collagen mRNA.CONCLUSIONS: Our study shows that CITP, PIIINP, and P4NP 7S do not reflect myocardial collagen mRNA expression but presumably reflect extra-cardiac organ injury in heart failure.

    View details for PubMedID 30273997

  • SREBF1/MicroRNA-33b Axis Exhibits Potent Effect on Unstable Atherosclerotic Plaque Formation In Vivo ARTERIOSCLEROSIS THROMBOSIS AND VASCULAR BIOLOGY Nishino, T., Horie, T., Baba, O., Sowa, N., Hanada, R., Kuwabara, Y., Nakao, T., Nishiga, M., Nishi, H., Nakashima, Y., Nakazeki, F., Ide, Y., Koyama, S., Kimura, M., Nagata, M., Yoshida, K., Takagi, Y., Nakamura, T., Hasegawa, K., Miyamoto, S., Kimura, T., Ono, K. 2018; 38 (10): 2460–73
  • Loss of periostin ameliorates adipose tissue inflammation and fibrosis in vivo. Scientific reports Nakazeki, F., Nishiga, M., Horie, T., Nishi, H., Nakashima, Y., Baba, O., Kuwabara, Y., Nishino, T., Nakao, T., Ide, Y., Koyama, S., Kimura, M., Tsuji, S., Sowa, N., Yoshida, S., Conway, S. J., Yanagita, M., Kimura, T., Ono, K. 2018; 8 (1): 8553


    Recent evidence suggests that the accumulation of macrophages as a result of obesity-induced adipose tissue hypoxia is crucial for the regulation of tissue fibrosis, but the molecular mechanisms underlying adipose tissue fibrosis are still unknown. In this study, we revealed that periostin (Postn) is produced at extraordinary levels by adipose tissue after feeding with a high-fat diet (HFD). Postn was secreted at least from macrophages in visceral adipose tissue during the development of obesity, possibly due to hypoxia. Postn-/- mice had lower levels of crown-like structure formation and fibrosis in adipose tissue and were protected from liver steatosis. These mice also showed amelioration in systemic insulin resistance compared with HFD-fed WT littermates. Mice deficient in Postn in their hematopoietic compartment also had lower levels of inflammation in adipose tissue, in parallel with a reduction in ectopic lipid accumulation compared with the controls. Our data indicated that the regulation of Postn in visceral fat could be beneficial for the maintenance of healthy adipose tissue in obesity.

    View details for PubMedID 29867212

  • MicroRNA-33 regulates the population of peripheral inflammatory Ly6Chigh monocytes through dual pathways. Molecular and cellular biology Baba, O., Horie, T., Nakao, T., Hakuno, D., Nakashima, Y., Nishi, H., Kuwabara, Y., Nishiga, M., Nishino, T., Ide, Y., Nakazeki, F., Koyama, S., Kimura, M., Hanada, R., Kawahara, M., Kimura, T., Ono, K. 2018


    MicroRNA (miR)-33 targets ATP-binding cassette transporter A1 (ABCA1), and its deficiency increases serum HDL-cholesterol (HDL-C) and ameliorates atherosclerosis. Although we previously reported that miR-33 deficiency increased peripheral Ly6Chigh monocytes on ApoE-deficient background, the effect of miR-33 on monocyte population is not fully elucidated especially on wild-type (WT) background.We found that Ly6Chigh monocytes in miR-33-/- mice were decreased in peripheral blood and increased in bone marrow (BM). Expansion of myeloid progenitors and decreased apoptosis in LSK (Lin-Sca1+c-Kit+) cells were observed in miR-33-/- mice. BM transplantation study and competitive repopulation assay revealed that hematopoietic miR-33 deficiency caused myeloid expansion and increased peripheral Ly6Chigh monocytes, and nonhematopoietic miR-33 deficiency caused reduced peripheral Ly6Chigh monocytes. Expression of High mobility group AT-hook 2 (HMGA2) targeted by miR-33 increased in miR-33 deficient LSK cells, and its knockdown abolished the reduction of apoptosis. Transduction of human apolipoprotein A1 and ABCA1 in WT mouse liver increased HDL-C and reduced peripheral Ly6Chigh monocyte.These data indicate that miR-33 deficiency affects distribution of inflammatory monocytes through dual pathways. One is caused by enhancement of Hmga2 expression in hematopoietic stem cells to increase Ly6Chigh monocytes and the other is due to the elevation of HDL-C to decrease peripheral Ly6Chigh monocytes.

    View details for PubMedID 29712758

  • Induced pluripotent stem cells as a biopharmaceutical factory for extracellular vesicles. European heart journal Nishiga, M., Guo, H., Wu, J. C. 2018

    View details for PubMedID 29547885

  • Dynamic changes of serum microRNA-122-5p through therapeutic courses indicates amelioration of acute liver injury accompanied by acute cardiac decompensation. ESC heart failure Koyama, S., Kuragaichi, T., Sato, Y., Kuwabara, Y., Usami, S., Horie, T., Baba, O., Hakuno, D., Nakashima, Y., Nishino, T., Nishiga, M., Nakao, T., Arai, H., Kimura, T., Ono, K. 2017; 4 (2): 112-121


    Recent studies have shown that serum microRNA (miR) abundance is informative for the diagnosis or prognosis of heart failure. However, the dynamics and kinetics of miRs in acute heart failure are largely unknown. Serial measurement and analysis of serum miRs changes in individuals along their therapeutic course could reduce inter-individual variation and should detect potentially important serum miRs related to disease mechanisms. Based on this concept, we profiled serum miR signatures of blood samples that were obtained sequentially on the day of admission and on hospital Day 7.This prospective, observational study included 42 consecutive acute heart failure patients (74 ± 1 years old, 24 male). From admission to Day 7, most of the patients showed clinical improvement. In such a cohort, we detected several fluctuations of serum miRs by two distinct screening methods (quantitative PCR and high-throughput sequencing). One of these fluctuating serum miRs, miR-122-5p, decreased significantly from Day 1 to Day 7 [median arbitrary unit (1st:3rd quantile value); 4.62 [2.39:12.3] to 3.07 [1.67:5.39], P = 0.007]. This fluctuation was significantly correlated with changes in serum liver function markers (estimated coefficient and 95% confidence interval; vs change in aspartate aminotransferase 1.69, 0.890-2.484, P < 0.001 and r = 0.560, vs change in alanine aminotransferase 1.09, 0.406-1.771, P = 0.007 and r = 0.428).The serum miR signature of patients with acute heart failure might indicate the severity of the disease or patients' response to therapeutic intervention. Notably, serum miR-122-5p levels reflect liver damage in this condition.

    View details for DOI 10.1002/ehf2.12123

    View details for PubMedID 28451447

    View details for PubMedCentralID PMC5396046

  • MicroRNA-33 Controls Adaptive Fibrotic Response in the Remodeling Heart by Preserving Lipid Raft Cholesterol CIRCULATION RESEARCH Nishiga, M., Horie, T., Kuwabara, Y., Nagao, K., Baba, O., Nakao, T., Nishino, T., Hakuno, D., Nakashima, Y., Nishi, H., Nakazeki, F., Ide, Y., Koyama, S., Kimura, M., Hanada, R., Nakamura, T., Inada, T., Hasegawa, K., Conway, S. J., Kita, T., Kimura, T., Ono, K. 2017; 120 (5): 835-847


    Heart failure and atherosclerosis share the underlying mechanisms of chronic inflammation followed by fibrosis. A highly conserved microRNA (miR), miR-33, is considered as a potential therapeutic target for atherosclerosis because it regulates lipid metabolism and inflammation. However, the role of miR-33 in heart failure remains to be elucidated.To clarify the role of miR-33 involved in heart failure.We first investigated the expression levels of miR-33a/b in human cardiac tissue samples with dilated cardiomyopathy. Increased expression of miR-33a was associated with improving hemodynamic parameters. To clarify the role of miR-33 in remodeling hearts, we investigated the responses to pressure overload by transverse aortic constriction in miR-33-deficient (knockout [KO]) mice. When mice were subjected to transverse aortic constriction, miR-33 expression levels were significantly upregulated in wild-type left ventricles. There was no difference in hypertrophic responses between wild-type and miR-33KO hearts, whereas cardiac fibrosis was ameliorated in miR-33KO hearts compared with wild-type hearts. Despite the ameliorated cardiac fibrosis, miR-33KO mice showed impaired systolic function after transverse aortic constriction. We also found that cardiac fibroblasts were mainly responsible for miR-33 expression in the heart. Deficiency of miR-33 impaired cardiac fibroblast proliferation, which was considered to be caused by altered lipid raft cholesterol content. Moreover, cardiac fibroblast-specific miR-33-deficient mice also showed decreased cardiac fibrosis induced by transverse aortic constriction as systemic miR-33KO mice.Our results demonstrate that miR-33 is involved in cardiac remodeling, and it preserves lipid raft cholesterol content in fibroblasts and maintains adaptive fibrotic responses in the remodeling heart.

    View details for DOI 10.1161/CIRCRESAHA.116.309528

    View details for Web of Science ID 000395592500022

    View details for PubMedID 27920122

  • Prevention of neointimal formation using miRNA-126-containing nanoparticle-conjugated stents in a rabbit model PLOS ONE Izuhara, M., Kuwabara, Y., Saito, N., Yamamoto, E., Hakuno, D., Nakashima, Y., Horie, T., Baba, O., Nishiga, M., Nakao, T., Nishino, T., Nakazeki, F., Ide, Y., Kimura, M., Kimura, T., Ono, K. 2017; 12 (3)


    Despite recent progress with drug-eluting stents, restenosis and thrombosis after endovascular intervention are still major limitations in the treatment of cardiovascular diseases. These problems are possibly caused by inappropriate inhibition of neointimal formation and retardation of re-endothelialization on the surface of the stents. miR-126 has been shown to have the potential to enhance vascular endothelial cell proliferation.We designed and constructed a 27-nt double strand RNA (dsRNA) conjugated to cholesterol, which has high membrane permeability, and formed mature miR-126 after transfection. For site-specific induction of miR-126, we utilized poly (DL-lactide-co-glycolide) nanoparticles (NPs). miR-126-dsRNA-containing NPs (miR-126 NPs) significantly reduced the protein expression of a previously identified miR-126 target, SPRED1, in human umbilical vascular endothelial cells (HUVECs), and miR-126 NPs enhanced the proliferation and migration of HUVECs. On the other hand, miR-126 NPs reduced the proliferation and migration of vascular smooth muscle cells, via the suppression of IRS-1. Finally, we developed a stent system that eluted miR-126. This delivery system exhibited significant inhibition of neointimal formation in a rabbit model of restenosis.miR-126 NP-conjugated stents significantly inhibited the development of neointimal hyperplasia in rabbits. The present study may indicate the possibility of a novel therapeutic option to prevent restenosis after angioplasty.

    View details for DOI 10.1371/journal.pone.0172798

    View details for Web of Science ID 000396011300033

    View details for PubMedID 28253326

    View details for PubMedCentralID PMC5333844

  • Genetic Ablation of MicroRNA-33 Attenuates Inflammation and Abdominal Aortic Aneurysm Formation via Several Anti-Inflammatory Pathways. Arteriosclerosis, thrombosis, and vascular biology Nakao, T., Horie, T., Baba, O., Nishiga, M., Nishino, T., Izuhara, M., Kuwabara, Y., Nishi, H., Usami, S., Nakazeki, F., Ide, Y., Koyama, S., Kimura, M., Sowa, N., Ohno, S., Aoki, H., Hasegawa, K., Sakamoto, K., Minatoya, K., Kimura, T., Ono, K. 2017; 37 (11): 2161–70


    Abdominal aortic aneurysm (AAA) is an increasingly prevalent and ultimately fatal disease with no effective pharmacological treatment. Because matrix degradation induced by vascular inflammation is the major pathophysiology of AAA, attenuation of this inflammation may improve its outcome. Previous studies suggested that miR-33 (microRNA-33) inhibition and genetic ablation of miR-33 increased serum high-density lipoprotein cholesterol and attenuated atherosclerosis.MiR-33a-5p expression in central zone of human AAA was higher than marginal zone. MiR-33 deletion attenuated AAA formation in both mouse models of angiotensin II- and calcium chloride-induced AAA. Reduced macrophage accumulation and monocyte chemotactic protein-1 expression were observed in calcium chloride-induced AAA walls in miR-33-/- mice. In vitro experiments revealed that peritoneal macrophages from miR-33-/- mice showed reduced matrix metalloproteinase 9 expression levels via c-Jun N-terminal kinase inactivation. Primary aortic vascular smooth muscle cells from miR-33-/- mice showed reduced monocyte chemotactic protein-1 expression by p38 mitogen-activated protein kinase attenuation. Both of the inactivation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase were possibly because of the increase of ATP-binding cassette transporter A1 that is a well-known target of miR-33. Moreover, high-density lipoprotein cholesterol derived from miR-33-/- mice reduced expression of matrix metalloproteinase 9 in macrophages and monocyte chemotactic protein-1 in vascular smooth muscle cells. Bone marrow transplantation experiments indicated that miR-33-deficient bone marrow cells ameliorated AAA formation in wild-type recipients. MiR-33 deficiency in recipient mice was also shown to contribute the inhibition of AAA formation.These data strongly suggest that inhibition of miR-33 will be effective as a novel strategy for treating AAA.

    View details for PubMedID 28882868

  • Predictors of Rapid Progression and Clinical Outcome of Asymptomatic Severe Aortic Stenosis CIRCULATION JOURNAL Nishimura, S., Izumi, C., Nishiga, M., Amano, M., Imamura, S., Onishi, N., Tamaki, Y., Enomoto, S., Miyake, M., Tamura, T., Kondo, H., Kaitani, K., Nakagawa, Y. 2016; 80 (8): 1863-1869


    The optimal timing of aortic valve replacement (AVR) is controversial in patients with asymptomatic severe aortic stenosis (AS) except when very severe. Prediction of progression of severe AS is helpful in deciding on the timing of AVR. The purpose of this study was to clarify the predictors of progression rate and clinical outcomes of severe AS.We retrospectively investigated 140 consecutive patients with asymptomatic severe AS (aortic valve area [AVA], 0.75-1.0 cm(2)). First-year progression rate and annual progression rate of AVA and of aortic jet velocity (AV-Vel) were calculated. Cardiac events were examined and the predictors of rapid progression and cardiac events were analyzed. The median follow-up period was 36 months. The median annual progression rate was -0.05 cm(2)/year for AVA and 0.22 m/s/year for AV-Vel. Dyslipidemia, moderate-severe calcification, and first-year AV-Vel progression ≥0.22 m/s/year were independent predictors of cardiac events. Cardiac event-free rate was lower in patients with AV-Vel first-year progression rate ≥0.22 m/s/year than in those with a lower rate. Diabetes and moderate-severe calcification were related to first-year rapid progression.The annual progression rate of severe AS was -0.05 cm(2)/year for AVA and 0.22 m/s/year for AV-Vel. Patients with first-year rapid progression or severely calcified aortic valve should be carefully observed while considering an early operation. (Circ J 2016; 80: 1863-1869).

    View details for DOI 10.1253/circj.CJ-16-0333

    View details for Web of Science ID 000381437500034

    View details for PubMedID 27334030

  • Prognostic Significance of ST-Segment Elevation in Leads V1-2 in Patients With Severe Aortic Stenosis CIRCULATION JOURNAL Taniguchi, T., Shiomi, H., Kosuge, M., Morimoto, T., Nakatsuma, K., Nishiga, M., Sasa, T., Saito, N., Kimura, T. 2016; 80 (2): 526-?


    ST-segment elevation (STE) in leads V1-2 is often observed in patients with severe aortic stenosis (AS), but its significance remains unknown.We retrospectively evaluated baseline ECGs and 5-year clinical outcomes in 211 consecutive patients with severe AS, defined as peak aortic jet velocity (Aortic Vmax) >4.0 m/s, or mean aortic pressure gradient >40 mmHg, or aortic valve area (AVA) <1.0 cm(2). The primary outcome measure was a composite of death or surgical aortic valve replacement (AVR). Patients with STE in leads V1-2(≥0.15 mV) had greater Aortic Vmax and smaller AVA than patients without. With a median follow-up of 4.9 years, the cumulative 5-year incidence of death or AVR was significantly higher in patients with STE in leads V1-2 than in patients without (91.4% vs. 77.1%; P=0.003). After adjusting for confounders, STE in leads V1-2 was independently associated with higher risk for death or AVR (hazard ratio, 1.53; 95% confidence interval, 1.06-2.22; P=0.02). In 64 asymptomatic patients without any indication for AVR at initial diagnosis of severe AS, the cumulative incidence of AVR was significantly higher in patients with STE in leads V1-2 than in patients without (57.6% vs. 30.5%; P<0.001).STE in leads V1-2 independently predicted poorer prognosis and more frequent need for AVR in patients with severe AS.

    View details for DOI 10.1253/circj.CJ-15-0641

    View details for Web of Science ID 000369376900037

    View details for PubMedID 26742587

  • Expression Patterns of miRNA-423-5p in the Serum and Pericardial Fluid in Patients Undergoing Cardiac Surgery PLOS ONE Miyamoto, S., Usami, S., Kuwabara, Y., Horie, T., Baba, O., Hakuno, D., Nakashima, Y., Nishiga, M., Izuhara, M., Nakao, T., Nishino, T., Ide, Y., Nakazeki, F., Wang, J., Ueyama, K., Kimura, T., Ono, K. 2015; 10 (11)


    Recently, it has been reported that specific microRNA (miRNA) levels are elevated in serum and can be used as biomarkers in patients with cardiovascular diseases. However, miRNAs expression profiles and their sources in pericardial fluid (PF) are unclear.The purpose of this study was to identify the levels of miRNAs in PF in relation to those in the serum in patients undergoing cardiac surgery. Serum (S) and PF from patients undergoing coronary artery bypass graft (CABG) due to stable angina pectoris (sAP) and unstable AP (uAP) and aortic valve replacement due to aortic stenosis (AS) were analyzed for the detection of miRNAs. We named these samples S-sAP, S-uAP, S-AS, PF-sAP, PF-uAP, and PF-AS, respectively. We first measured the levels of miR-423-5p, which was recognized previously as a biomarker for heart failure. miR-423-5p levels were significantly higher in PF than serum. Although there was no difference in miR-423-5p levels among the PF-AS, PF-sAP, and PF-uAP, its levels were significantly elevated in S-uAP compared with those in S-AS and S-sAP. In order to clarify the source of miR-423-5p in PF, we measured the levels of muscle-enriched miR-133a and vascular-enriched miR-126 and miR-92a in the same samples. miR-133a levels were significantly higher in serum than in PF, and it was elevated in S-uAP compared with S-AS. miR-126 level was significantly increased in serum compared with PF, and the level of miR-92a the similar tendency. miR-423-5p is located in the first intron of NSRP1. There is another miRNA, miR-3184, encoded in the opposite direction in the same region. In vitro experiments indicated that the duplex of miR-423-5p and miR-3184-3p was more resistant to RNase than the duplex of miR-423-5p and miR-133-3p, which may help to stabilize miR-423-5p in the PF.Our results suggested that miR-423-5p is enriched in PF, and serum miR-423-5p may be associate with uAP. Its expression pattern was different to that of muscle- and vascular-enriched miRNAs, miR-133a, miR-126, and miR-92a.

    View details for DOI 10.1371/journal.pone.0142904

    View details for Web of Science ID 000364480900080

    View details for PubMedID 26562412

    View details for PubMedCentralID PMC4642962

  • Acute myocardial infarction and 30-year coronary aneurysm follow-up by serial angiography in a young adult with Kawasaki disease. Cardiovascular intervention and therapeutics Matsushita, K., Tamura, T., Nishiga, M., Kaitani, K., Izumi, C., Nakagawa, Y. 2015; 30 (2): 142-146


    The number of adult patients with coronary artery disease caused by Kawasaki disease (KD) is gradually increasing, but some patients drop out of clinical follow-up. However, careful, long-term follow-up and establishment of an optimal treatment strategy are needed in these patients, as well as cooperation between pediatric and adult cardiologists. We report a case of acute myocardial infarction in a young adult patient with KD whose serial coronary angiography was followed up for over 30 years. Successful reperfusion therapy was performed with thrombus aspiration, rotational atherectomy, and implantation of a drug-eluting stent.

    View details for DOI 10.1007/s12928-014-0262-8

    View details for PubMedID 24729026

  • MicroRNA-451 Exacerbates Lipotoxicity in Cardiac Myocytes and High-Fat Diet-Induced Cardiac Hypertrophy in Mice Through Suppression of the LKB1/AMPK Pathway CIRCULATION RESEARCH Kuwabara, Y., Horie, T., Baba, O., Watanabe, S., Nishiga, M., Usami, S., Izuhara, M., Nakao, T., Nishino, T., Otsu, K., Kita, T., Kimura, T., Ono, K. 2015; 116 (2): 279-U217


    In some patients with type 2 diabetes mellitus (DM) without hypertension, cardiac hypertrophy and attenuated cardiac function are observed, and this insult is termed diabetic cardiomyopathy. To date, microRNA (miRNAs or miR) functions in diabetic cardiomyopathy remain to be elucidated.To clarify the functions of miRNAs involved in diabetic cardiomyopathy caused by type 2 DM.C57BL/6 mice were fed a high-fat diet (HFD) for 20 weeks, which induced obesity and type 2 DM. miRNA microarray analyses and real-time polymerase chain reaction revealed that miR-451 levels were significantly increased in the type 2 DM mouse hearts. Because excess supply of saturated fatty acids is a cause of diabetic cardiomyopathy, we stimulated neonatal rat cardiac myocytes with palmitic acid and confirmed that miR-451 expression was increased in a dose- and time-dependent manner. Loss of miR-451 function ameliorated palmitate-induced lipotoxicity in neonatal rat cardiac myocytes. Calcium-binding protein 39 (Cab39) is a scaffold protein of liver kinase B1 (LKB1), an upstream kinase of AMP-activated protein kinase (AMPK). Cab39 was a direct target of miR-451 in neonatal rat cardiac myocytes and Cab39 overexpression rescued the lipotoxicity. To clarify miR-451 functions in vivo, we generated cardiomyocyte-specific miR-451 knockout mice. HFD-induced cardiac hypertrophy and contractile reserves were ameliorated in cardiomyocyte-specific miR-451 knockout mice compared with control mice. Protein levels of Cab39 and phosphorylated AMPK were increased and phosphorylated mammalian target of rapamycin (mTOR) was reduced in cardiomyocyte-specific miR-451 knockout mouse hearts compared with control mouse hearts.Our results demonstrate that miR-451 is involved in diabetic cardiomyopathy through suppression of the LKB1/AMPK pathway.

    View details for DOI 10.1161/CIRCRESAHA.116.304707

    View details for Web of Science ID 000347939000013

    View details for PubMedID 25362209

  • MicroRNA-33b knock-in mice for an intron of sterol regulatory element-binding factor 1 (Srebf1) exhibit reduced HDL-C in vivo SCIENTIFIC REPORTS Horie, T., Nishino, T., Baba, O., Kuwabara, Y., Nakao, T., Nishiga, M., Usami, S., Izuhara, M., Nakazeki, F., Ide, Y., Koyama, S., Sowa, N., Yahagi, N., Shimano, H., Nakamura, T., Hasegawa, K., Kume, N., Yokode, M., Kita, T., Kimura, T., Ono, K. 2014; 4


    MicroRNAs (miRs) are small non-protein-coding RNAs that bind to specific mRNAs and inhibit translation or promote mRNA degradation. Recent reports, including ours, indicated that miR-33a located within the intron of sterol regulatory element-binding protein (SREBP) 2 controls cholesterol homeostasis and can be a possible therapeutic target for treating atherosclerosis. Primates, but not rodents, express miR-33b from an intron of SREBF1. Therefore, humanized mice, in which a miR-33b transgene is inserted within a Srebf1 intron, are required to address its function in vivo. We successfully established miR-33b knock-in (KI) mice and found that protein levels of known miR-33a target genes, such as ABCA1, ABCG1, and SREBP-1, were reduced compared with those in wild-type mice. As a consequence, macrophages from the miR-33b KI mice had a reduced cholesterol efflux capacity via apoA-I and HDL-C. Moreover, HDL-C levels were reduced by almost 35% even in miR-33b KI hetero mice compared with the control mice. These results indicate that miR-33b may account for lower HDL-C levels in humans than those in mice and that miR-33b is possibly utilized for a feedback mechanism to regulate its host gene SREBF1. Our mice will also aid in elucidating the roles of miR-33a/b in different genetic disease models.

    View details for DOI 10.1038/srep05312

    View details for Web of Science ID 000337341400009

    View details for PubMedID 24931346

    View details for PubMedCentralID PMC4058878

  • MicroRNA-33 regulates sterol regulatory element-binding protein 1 expression in mice NATURE COMMUNICATIONS Horie, T., Nishino, T., Baba, O., Kuwabara, Y., Nakao, T., Nishiga, M., Usami, S., Izuhara, M., Sowa, N., Yahagi, N., Shimano, H., Matsumura, S., Inoue, K., Marusawa, H., Nakamura, T., Hasegawa, K., Kume, N., Yokode, M., Kita, T., Kimura, T., Ono, K. 2013; 4


    MicroRNAs (miRs) are small non-protein-coding RNAs that bind to specific mRNAs and inhibit translation or promote mRNA degradation. Recent reports have indicated that miR-33, which is located within the intron of sterol regulatory element-binding protein (SREBP) 2, controls cholesterol homoeostasis and may be a potential therapeutic target for the treatment of atherosclerosis. Here we show that deletion of miR-33 results in marked worsening of high-fat diet-induced obesity and liver steatosis. Using miR-33(-/-)Srebf1(+/-) mice, we demonstrate that SREBP-1 is a target of miR-33 and that the mechanisms leading to obesity and liver steatosis in miR-33(-/-) mice involve enhanced expression of SREBP-1. These results elucidate a novel interaction between SREBP-1 and SREBP-2 mediated by miR-33 in vivo.

    View details for DOI 10.1038/ncomms3883

    View details for Web of Science ID 000329396200001

    View details for PubMedID 24300912

    View details for PubMedCentralID PMC3863899

  • Effects of Medical Treatment on the Prognosis and Risk of Embolic Events in Patients with Severe Aortic Plaque JOURNAL OF ATHEROSCLEROSIS AND THROMBOSIS Nishiga, M., Izumi, C., Matsutani, H., Hashiwada, S., Takahashi, S., Hayama, Y., Nakajima, S., Sakamoto, J., Hanazawa, K., Miyake, M., Tamura, T., Kondo, H., Motooka, M., Kaitani, K., Nakagawa, Y. 2013; 20 (11): 821-829


    The optimal treatment strategy for patients with aortic atheroma is not well established because data regarding medical treatment for such patients are lacking, especially with respect to the Japanese population. The purpose of this study was to clarify the effects of medical treatment on the risk of embolic events and mortality in patients with severe aortic plaque.We retrospectively investigated 75 consecutive patients with severe aortic plaque detected on transesophageal echocardiography (TEE) between 1995 and 2005. The occurrence of embolic events and all-cause death in the period after TEE was assessed. The cumulative incidence of subsequent embolic events and death was evaluated in relation to specific medical treatments, including statins, antiplatelet drugs and warfarin.Embolic events occurred in 27 patients (36%) and death occurred in 37 patients (49%) during follow-up (5.6±3.0 years). The patients who experienced embolic events had a significantly higher prevalence of previous embolic events, atrial fibrillation and hemodialysis than the patients who did not experience embolic events. Univariate and multivariate analyses showed that the use of statins and/or antiplatelet drugs was significantly associated with a low incidence of death but not with a low incidence of embolic events. On the other hand, warfarin exhibited neither beneficial nor harmful effects on the incidence of embolic events or death.Statin and antiplatelet drugs have beneficial effects on the prognosis of patients with severe aortic plaque diagnosed on TEE.

    View details for Web of Science ID 000327863900005

    View details for PubMedID 23955519

  • A case of significantly increased mitral regurgitation early after atrial septal defect closure. Journal of echocardiography Nishiga, M., Izumi, C., Matsutani, H., Hashiwada, S., Takahashi, S., Hayama, Y., Nakajima, S., Sakamoto, J., Hanazawa, K., Miyake, M., Tamura, T., Kondo, H., Motooka, M., Kaitani, K., Nakagawa, Y. 2012; 10 (2): 69-71


    We report a rare case in which mitral regurgitation (MR) was exacerbated to a severe level early after atrial septal defect (ASD) closure, even though the female patient had preoperatively mild MR and mild changes in mitral valve (MV) and sinus rhythm. The mechanism of increased MR was considered as poor coaptation and tethering of the MV due to the restricted motion of the posterior leaflet in addition to geometric changes of the left ventricle (LV) after ASD closure.

    View details for DOI 10.1007/s12574-012-0123-3

    View details for PubMedID 27278048

  • Progression of Isolated Tricuspid Regurgitation Late After Left-Sided Valve Surgery - Clinical Features and Mechanisms CIRCULATION JOURNAL Izumi, C., Miyake, M., Takahashi, S., Matsutani, H., Hashiwada, S., Kuwano, K., Hayashi, H., Nakajima, S., Nishiga, M., Hanazawa, K., Sakamoto, J., Kondo, H., Tamura, T., Kaitani, K., Yamanaka, K., Nakagawa, Y. 2011; 75 (12): 2902-2907


    Severe tricuspid regurgitation (TR) sometimes develops late after left-sided valve surgery without left heart failure, pulmonary hypertension or rheumatic tricuspid valve. The purpose of the present study was to investigate clinical characteristics and mechanisms of severe isolated TR late after left-sided valve surgery.A total of 372 consecutive patients who underwent left-sided valve surgery between 1990 and 2003 and who were followed up with echocardiography for at least 5 years, were retrospectively investigated. The mean follow-up period was 9.4 years. Clinical background, preoperative and postoperative echocardiographic parameters were evaluated. Among the 372 patients, severe isolated TR was detected in 23 patients, which developed at a mean of 8.6 years after surgery. Twenty-two of 23 patients had undergone mitral valve surgery. Multivariate logistic regression analysis identified the presence of preoperative atrial fibrillation and preoperative ejection fraction as independent determinants for the development of severe isolated TR. In patients with severe isolated TR, the tricuspid annular diameter and the right atrial area were already enlarged early after surgery and both of these increased prior to TR progression.Severe isolated TR developing late after mitral valve surgery is not uncommon, thus it is important to recognize this disease entity. Annular dilatation was the main cause of isolated TR and serial echocardiographic data are important to detect progression of isolated TR and to assess its mechanisms.

    View details for DOI 10.1253/circj.CJ-11-0718

    View details for Web of Science ID 000297567600032

    View details for PubMedID 21946358

  • Cardiac tamponade during transesophageal echocardiography in a patient with infective endocarditis. Journal of echocardiography Miyake, M., Izumi, C., Kuwano, K., Honjo, G., Matsutani, H., Hashiwada, S., Takahashi, S., Nishiga, M., Nakajima, S., Yamao, K., Hanazawa, K., Sakamoto, J., Yoshitani, K., Motooka, M., Kaitani, K., Izumi, T., Kobashi, Y., Nakagawa, Y. 2010; 8 (1): 25-27


    An 81-year-old man with a history of diabetes mellitus and end-stage renal disease was admitted because of infective endocarditis. During transesophageal echocardiography (TEE), pericardial effusion rapidly increased and led to cardiac tamponade. Despite intensive therapy, the patient did not recover. Autopsy showed hemopericardium, ruptured sinus of Valsalva, and vegetation on the aortic valve. Our case suggests that cardiac tamponade due to the rupture of a sinus of Valsalva can occur in patients with aortic valve endocarditis complicated by perivalvular abscess. Therefore, we must be aware of this devastating complication and take preventive measures when performing TEE in such patients.

    View details for DOI 10.1007/s12574-009-0023-3

    View details for PubMedID 27278541