研究者総覧

桂田 健一 (カツラダ ケンイチ)

  • 薬理学講座(臨床薬理学部門) 講師
Last Updated :2021/09/22

研究者情報

学位

  • 医学博士(2015年03月 自治医科大学)

ホームページURL

科研費研究者番号

  • 70598630

ORCID ID

J-Global ID

研究分野

  • ライフサイエンス / 循環器内科学

経歴

  • 2021年09月 - 現在  自治医科大学薬理学講座臨床薬理学部門講師
  • 2020年06月 - 2021年08月  自治医科大学薬理学講座臨床薬理学部門助教
  • 2020年04月 - 2020年05月  自治医科大学内科学講座循環器内科学部門病院助教
  • 2017年04月 - 2020年03月  ネブラスカ大学医療センター統合生理学講座ポスドク
  • 2015年04月 - 2017年03月  上都賀総合病院循環器内科医長
  • 2011年01月 - 2015年03月  自治医科大学内科学講座循環器内科学部門臨床助教
  • 2009年07月 - 2010年12月  宇都宮社会保険病院(現JCHOうつのみや)循環器内科医員
  • 2008年04月 - 2009年06月  自治医科大学内科学講座循環器内科学部門臨床助教
  • 2007年04月 - 2008年03月  自治医科大学附属病院後期内科研修医
  • 2005年04月 - 2007年03月  自治医科大学附属病院初期研修医

学歴

  • 2011年04月 - 2015年03月   自治医科大学大学院医学研究科博士課程
  • 1999年04月 - 2005年03月   秋田大学医学部医学科

研究活動情報

論文

  • Kenichi Katsurada, Kazuomi Kario
    Journal of clinical hypertension (Greenwich, Conn.) 2021年08月
  • Neeru M Sharma, Andréa S Haibara, Kenichi Katsurada, Shyam S Nandi, Xuefei Liu, Hong Zheng, Kaushik P Patel
    Hypertension (Dallas, Tex. : 1979) 77 1 147 - 157 2021年01月 
    Central infusion of Ang II (angiotensin II) has been associated with increased sympathetic outflow resulting in neurogenic hypertension. In the present study, we appraised whether the chronic increase in central Ang II activates the paraventricular nucleus of the hypothalamus (PVN) resulting in elevated sympathetic tone and altered baro- and chemoreflexes. Further, we evaluated the contribution of HIF-1α (hypoxia-inducible factor-1α), a transcription factor involved in enhancing the expression of N-methyl-D-aspartate receptors and thus glutamatergic-mediated sympathetic tone from the PVN. Ang II infusion (20 ng/minute, intracerebroventricular, 14 days) increased mean arterial pressure (126±9 versus 84±4 mm Hg), cardiac sympathetic tone (96±7 versus 75±6 bpm), and decreased cardiac parasympathetic tone (16±2 versus 36±3 versus bpm) compared with saline-infused controls in conscious rats. The Ang II-infused group also showed an impaired baroreflex control of heart rate (-1.50±0.1 versus -2.50±0.3 bpm/mm Hg), potentiation of the chemoreflex pressor response (53±7 versus 30±7 mm Hg) and increased number of FosB-labeled cells (53±3 versus 19±4) in the PVN. Concomitant with the activation of the PVN, there was an increased expression of HIF-1α and N-Methyl-D-Aspartate-type1 receptors in the PVN. Further, Ang II-infusion showed increased renal sympathetic nerve activity (20.5±2.3% versus 6.4±1.9% of Max) and 3-fold enhanced renal sympathetic nerve activity responses to microinjection of N-methyl-D-aspartate (200 pmol) into the PVN of anesthetized rats. Further, silencing of HIF-1α in NG108 cells abrogated the expression of N-methyl-D-aspartate-N-methyl-D-aspartate-type1 induced by Ang II. Taken together, our studies suggest a novel Ang II-HIF-1α-N-methyl-D-aspartate receptor-mediated activation of preautonomic neurons in the PVN, resulting in increased sympathetic outflow and alterations in baro- and chemoreflexes.
  • Shyam Sundar Nandi, Kenichi Katsurada, Neeru M Sharma, Daniel R Anderson, Sushil K Mahata, Kaushik P Patel
    American journal of physiology. Heart and circulatory physiology 2020年10月 
    An increased matrix metalloprotease9 (MMP9) during post-myocardial infarction (post-MI) exacerbates ischemia-induced chronic heart failure (CHF). Autophagy is cardioprotective during CHF, however, whether increased MMP9 suppressed autophagic activity in CHF is unknown. This study aimed to determine whether the increased MMP9 suppressed autophagic flux, and MMP9 inhibition increased autophagic flux in the heart of rats with Post-MI CHF. Sprague-Dawley rats underwent either Sham or coronary artery ligation, 6-8 weeks prior to being treated with MMP9-inhibitor for 7days, followed by cardiac autophagic flux measurement using lysosomal inhibitor BafilomycinA1. Further, autophagic flux was measured in vitro by treating H9c2 cardiomyocytes with two independent pharmacological MMP9 inhibitors, Salvianolic-Acid-B (SalB) or MMP9-inhibitor-I, and CRISPR/cas9-mediated MMP9 genetic ablation. CHF rats showed cardiac infarct, significantly increased left ventricular end-diastolic pressure (LVEDP), and increased MMP9 activity and fibrosis in the peri-infarct areas of left-ventricular myocardium. The autophagic markers LC3B-II and p62 measurement with lysosomal inhibition showed decreased autophagic flux in the peri-infarct myocardium. Treatment with SalB for 7days in CHF rats decreased MMP9 activity, cardiac fibrosis, and increased autophagic flux in the peri-infarct myocardium. As an in vitro corollary study, measurement of autophagic flux in H9c2 cardiomyocytes and fibroblasts showed that pharmacological inhibition or genetic ablation of MMP9 upregulates autophagic flux. These data are consistent with our observations that MMP9 inhibition upregulates autophagic flux in the heart of rats with CHF. In conclusion, the results in this study suggest that the beneficial outcome of MMP9 inhibition on pathological cardiac remodeling is in part mediated by improved autophagic flux.
  • Li Zheng, Andrew J Trease, Kenichi Katsurada, Gaelle Spagnol, Hanjun Li, Wen Shi, Bin Duan, Kaushik P Patel, Paul L Sorgen
    Journal of molecular and cellular cardiology 149 27 - 40 2020年09月 [査読有り][通常論文]
     
    Identification of proteins that interact with Cx43 has been instrumental in the understanding of gap junction (GJ) regulation. An in vitro phosphorylation screen identified that Protein tyrosine kinase 2 beta (Pyk2) phosphorylated purified Cx43CT and this led us to characterize the impact of this phosphorylation on Cx43 function. Mass spectrometry identified Pyk2 phosphorylates Cx43 residues Y247, Y265, Y267, and Y313. Western blot and immunofluorescence staining using HeLaCx43 cells, HEK 293 T cells, and neonatal rat ventricular myocytes (NRVMs) revealed Pyk2 can be activated by Src and active Pyk2 interacts with Cx43 at the plasma membrane. Overexpression of Pyk2 increases Cx43 phosphorylation and knock-down of Pyk2 decreases Cx43 phosphorylation, without affecting the level of active Src. In HeLaCx43 cells treated with PMA to activate Pyk2, a decrease in Cx43 GJ intercellular communication (GJIC) was observed when assayed by dye transfer. Moreover, PMA activation of Pyk2 could be inhibited by the small molecule PF4618433. This partially restored GJIC, and when paired with a Src inhibitor, returned GJIC to the no PMA control-level. The ability of Pyk2 and Src inhibitors to restore Cx43 function in the presence of PMA was also observed in NRVMs. Additionally, an animal model of myocardial infarction induced heart failure showed a higher level of active Pyk2 activity and increased interaction with Cx43 in ventricular myocytes. Src inhibitors have been used to reverse Cx43 remodeling and improve heart function after myocardial infarction; however, they alone could not fully restore proper Cx43 function. Our data suggest that Pyk2 may need to be inhibited, in addition to Src, to further (if not completely) reverse Cx43 remodeling and improve intercellular communication.
  • Sarah L Schlichte, Svetlana Romanova, Kenichi Katsurada, Elizabeth A Kosmacek, Tatiana K Bronich, Kaushik P Patel, Rebecca E Oberley-Deegan, Matthew C Zimmerman
    Redox biology 36 101610 - 101610 2020年09月 [査読有り][通常論文]
     
    Scavenging superoxide (O2•-) via overexpression of superoxide dismutase (SOD) or administration of SOD mimics improves outcomes in multiple experimental models of human disease including cardiovascular disease, neurodegeneration, and cancer. While few SOD mimics have transitioned to clinical trials, MnTnBuOE-2-PyP5+ (BuOE), a manganese porphyrin SOD mimic, is currently in clinical trials as a radioprotector for cancer patients; thus, providing hope for the use of SOD mimics in the clinical setting. However, BuOE transiently alters cardiovascular function including a significant and precipitous decrease in blood pressure. To limit BuOE's acute hypotensive action, we developed a mesoporous silica nanoparticle and lipid bilayer nanoformulation of BuOE (nanoBuOE) that allows for slow and sustained release of the drug. Herein, we tested the hypothesis that unlike native BuOE, nanoBuOE does not induce an acute hypotensive response, as the nanoformulation prevents BuOE from scavenging O2•- while the drug is still encapsulated in the formulation. We report that intact nanoBuOE does not effectively scavenge O2•-, whereas BuOE released from the nanoformulation does retain SOD-like activity. Further, in mice, native BuOE, but not nanoBuOE, rapidly, acutely, and significantly decreases blood pressure, as measured by radiotelemetry. To begin exploring the physiological mechanism by which native BuOE acutely decreases blood pressure, we recorded renal sympathetic nerve activity (RSNA) in rats. RSNA significantly decreased immediately following intravenous injection of BuOE, but not nanoBuOE. These data indicate that nanoformulation of BuOE, a SOD mimic currently in clinical trials in cancer patients, prevents BuOE's negative side effects on blood pressure homeostasis.
  • Kenichi Katsurada, Shyam S Nandi, Hong Zheng, Xuefei Liu, Neeru M Sharma, Kaushik P Patel
    Cardiovascular diabetology 19 1 57 - 57 2020年05月 [査読有り][通常論文]
     
    BACKGROUND: Glucagon-like peptide-1 (GLP-1) induces diuresis and natriuresis. Previously we have shown that GLP-1 activates afferent renal nerve to increase efferent renal sympathetic nerve activity that negates the diuresis and natriuresis as a negative feedback mechanism in normal rats. However, renal effects of GLP-1 in heart failure (HF) has not been elucidated. The present study was designed to assess GLP-1-induced diuresis and natriuresis in rats with HF and its interactions with renal nerve activity. METHODS: HF was induced in rats by coronary artery ligation. The direct recording of afferent renal nerve activity (ARNA) with intrapelvic injection of GLP-1 and total renal sympathetic nerve activity (RSNA) with intravenous infusion of GLP-1 were performed. GLP-1 receptor expression in renal pelvis, densely innervated by afferent renal nerve, was assessed by real-time PCR and western blot analysis. In separate group of rats after coronary artery ligation selective afferent renal denervation (A-RDN) was performed by periaxonal application of capsaicin, then intravenous infusion of GLP-1-induced diuresis and natriuresis were evaluated. RESULTS: In HF, compared to sham-operated control; (1) response of increase in ARNA to intrapelvic injection of GLP-1 was enhanced (3.7 ± 0.4 vs. 2.0 ± 0.4 µV s), (2) GLP-1 receptor expression was increased in renal pelvis, (3) response of increase in RSNA to intravenous infusion of GLP-1 was enhanced (132 ± 30% vs. 70 ± 16% of the baseline level), and (4) diuretic and natriuretic responses to intravenous infusion of GLP-1 were blunted (urine flow 53.4 ± 4.3 vs. 78.6 ± 4.4 µl/min/gkw, sodium excretion 7.4 ± 0.8 vs. 10.9 ± 1.0 µEq/min/gkw). A-RDN induced significant increases in diuretic and natriuretic responses to GLP-1 in HF (urine flow 96.0 ± 1.9 vs. 53.4 ± 4.3 µl/min/gkw, sodium excretion 13.6 ± 1.4 vs. 7.4 ± 0.8 µEq/min/gkw). CONCLUSIONS: The excessive activation of neural circuitry involving afferent and efferent renal nerves suppresses diuretic and natriuretic responses to GLP-1 in HF. These pathophysiological responses to GLP-1 might be involved in the interaction between incretin-based medicines and established HF condition. RDN restores diuretic and natriuretic effects of GLP-1 and thus has potential beneficial therapeutic implication for diabetic HF patients.
  • Neeru M Sharma, Andrea S Haibara, Kenichi Katsurada, Xuefei Liu, Kaushik P Patel
    Nitric oxide : biology and chemistry 94 54 - 62 2020年01月 [査読有り][通常論文]
     
    Activation of renin-angiotensin- system, nitric oxide (NO•) bioavailability and subsequent sympathoexcitation plays a pivotal role in the pathogenesis of many cardiovascular diseases, including hypertension. Previously we have shown increased protein expression of PIN (a protein inhibitor of nNOS: neuronal nitric oxide synthase, known to dissociate nNOS dimers into monomers) with concomitantly reduced levels of catalytically active dimers of nNOS in the PVN of rats with heart failure. To elucidate the molecular mechanism by which Angiotensin II (Ang II) increases PIN expression, we used Sprague-Dawley rats (250-300 g) subjected to intracerebroventricular infusion of Ang II (20 ng/min, 0.5 μl/h) or saline as vehicle (Veh) for 14 days through osmotic mini-pumps and NG108-15 hybrid neuronal cell line treated with Ang II as an in vitro model. Ang II infusion significantly increased baseline renal sympathetic nerve activity and mean arterial pressure. Ang II infusion increased the expression of PIN (1.24 ± 0.04* Ang II vs. 0.65 ± 0.07 Veh) with a concomitant 50% decrease in dimeric nNOS and PIN-Ub conjugates (0.73 ± 0.04* Ang II vs. 1.00 ± 0.03 Veh) in the PVN. Substrate-dependent ligase assay in cells transfected with pCMV-(HA-Ub)8 vector revealed a reduction of HA-Ub-PIN conjugates after Ang II and a proteasome inhibitor, Lactacystin (LC), treatment (4.5 ± 0.7* LC Ang II vs. 9.2 ± 2.5 LC). TUBE (Tandem Ubiquitin-Binding Entities) assay showed decrease PIN-Ub conjugates in Ang II-treated cells (0.82 ± 0.12* LC Ang II vs. 1.21 ± 0.06 LC) while AT1R blocker, Losartan (Los) treatment diminished the Ang II-mediated stabilization of PIN (1.21 ± 0.07 LC Los vs. 1.16 ± 0.04* LC Ang II Los). Taken together, our studies suggest that increased central levels of Ang II contribute to the enhanced expression of PIN leading to reduced expression of the dimeric form of nNOS, thus diminishing the inhibitory action of NO• on pre-autonomic neurons in the PVN resulting in increased sympathetic outflow.
  • Hong Zheng, Xuefei Liu, Kenichi Katsurada, Kaushik P Patel
    American journal of physiology. Heart and circulatory physiology 317 5 H958-H968  2019年11月 [査読有り][通常論文]
     
    Previously we have shown that increased expression of renal epithelial sodium channels (ENaC) may contribute to the renal sodium and water retention observed during chronic heart failure (CHF). The goal of this study was to examine whether renal denervation (RDN) changed the expressions of renal sodium transporters ENaC, sodium-hydrogen exchanger-3 proteins (NHE3), and water channel aquaporin 2 (AQP2) in rats with CHF. CHF was produced by left coronary artery ligation in rats. Four weeks after ligation surgery, surgical bilateral RDN was performed. The expression of ENaC, NHE3, and AQP2 in both renal cortex and medulla were measured. As a functional test for ENaC activation, diuretic and natriuretic responses to ENaC inhibitor benzamil were monitored in four groups of rats (Sham, Sham+RDN, CHF, CHF+RDN). Western blot analysis indicated that RDN (1 wk later) significantly reduced protein levels of α-ENaC, β-ENaC, γ-ENaC, and AQP2 in the renal cortex of CHF rats. RDN had no significant effects on the protein expression of kidney NHE3 in both Sham and CHF rats. Immunofluorescence studies of kidney sections confirmed the reduced signaling of ENaC and AQP2 in the CHF+RDN rats compared with the CHF rats. There were increases in diuretic and natriuretic responses to ENaC inhibitor benzamil in rats with CHF. RDN reduced the diuretic and natriuretic responses to benzamil in CHF rats. These findings suggest a critical role for renal nerves in the enhanced expression of ENaC and AQP2 and subsequent pathophysiology of renal sodium and water retention associated with CHF.NEW & NOTEWORTHY This is the first study to show in a comprehensive way that renal denervation initiated after a period of chronic heart failure reduces the expression of epithelial sodium channels and aquaporin 2 leading to reduced epithelial sodium channel function and sodium retention.
  • Kenichi Katsurada, Shyam S Nandi, Neeru M Sharma, Hong Zheng, Xuefei Liu, Kaushik P Patel
    American journal of physiology. Renal physiology 317 4 F1010-F1021  2019年10月 [査読有り][通常論文]
     
    Glucagon-like peptide-1 (GLP-1), an incretin hormone, has diuretic and natriuretic effects. The present study was designed to explore the possible underlying mechanisms for the diuretic and natriuretic effects of GLP-1 via renal nerves in rats. Immunohistochemistry revealed that GLP-1 receptors were avidly expressed in the pelvic wall, the wall being adjacent to afferent renal nerves immunoreactive to calcitonin gene-related peptide, which is the dominant neurotransmitter for renal afferents. GLP-1 (3 μM) infused into the left renal pelvis increased ipsilateral afferent renal nerve activity (110.0 ± 15.6% of basal value). Intravenous infusion of GLP-1 (1 µg·kg-1·min-1) for 30 min increased renal sympathetic nerve activity (RSNA). After the distal end of the renal nerve was cut to eliminate the afferent signal, the increase in efferent renal nerve activity during intravenous infusion of GLP-1 was diminished compared with the increase in total RSNA (17.0 ± 9.0% vs. 68.1 ± 20.0% of the basal value). Diuretic and natriuretic responses to intravenous infusion of GLP-1 were enhanced by total renal denervation (T-RDN) with acute surgical cutting of the renal nerves. Selective afferent renal nerve denervation (A-RDN) was performed by bilateral perivascular application of capsaicin on the renal nerves. Similar to T-RDN, A-RDN enhanced diuretic and natriuretic responses to GLP-1. Urine flow and Na+ excretion responses to GLP-1 were not significantly different between T-RDN and A-RDN groups. These results indicate that the diuretic and natriuretic effects of GLP-1 are partly governed via activation of afferent renal nerves by GLP-1 acting on sensory nerve fibers within the pelvis of the kidney.
  • Kenichi Katsurada, Masanori Nakata, Toshinobu Saito, Boyang Zhang, Yuko Maejima, Shyam S Nandi, Neeru M Sharma, Kaushik P Patel, Kazuomi Kario, Toshihiko Yada
    Scientific reports 9 1 12986 - 12986 2019年09月 [査読有り][通常論文]
     
    Glucagon-like peptide-1 receptor (GLP-1R) agonists, widely used to treat type 2 diabetes, reduce blood pressure (BP) in hypertensive patients. Whether this action involves central mechanisms is unknown. We here report that repeated lateral ventricular (LV) injection of GLP-1R agonist, liraglutide, once daily for 15 days counteracted the development of hypertension in spontaneously hypertensive rats (SHR). In parallel, it suppressed urinary norepinephrine excretion, and induced c-Fos expressions in the area postrema (AP) and nucleus tractus solitarius (NTS) of brainstem including the NTS neurons immunoreactive to dopamine beta-hydroxylase (DBH). Acute administration of liraglutide into fourth ventricle, the area with easy access to the AP and NTS, transiently decreased BP in SHR and this effect was attenuated after lesion of NTS DBH neurons with anti-DBH conjugated to saporin (anti-DBH-SAP). In anti-DBH-SAP injected SHR, the antihypertensive effect of repeated LV injection of liraglutide for 14 days was also attenuated. These findings demonstrate that the central GLP-1R signaling via NTS DBH neurons counteracts the development of hypertension in SHR, accompanied by attenuated sympathetic nerve activity.
  • Neeru M Sharma, Xuefei Liu, Tamra L Llewellyn, Kenichi Katsurada, Kaushik P Patel
    Nitric oxide : biology and chemistry 87 73 - 82 2019年06月 [査読有り][通常論文]
     
    Exercise training (ExT) is an established non-pharmacological therapy that improves the health and quality of life in patients with chronic heart failure (CHF). Exaggerated sympathetic drive characterizes CHF due to an imbalance of the autonomic nervous system. Neuronal nitric oxide synthase (nNOS) in the paraventricular nucleus (PVN) produce nitric oxide (NO•), which is known to regulate the sympathetic tone. Previously we have shown that during CHF, the catalytically active dimeric form of nNOS is significantly decreased with a concurrent increase in protein inhibitor of nNOS (PIN) expression, a protein that dissociates dimeric nNOS to monomers and facilitates its degradation. Dimerization of nNOS also requires (6R)-5,6,7,8-tetrahydrobiopterin (BH4) for stability and activity. Previously, we have shown that ExT improves NO-mediated sympathetic inhibition in the PVN; however, the molecular mechanism remains elusive. We hypothesized; ExT restores the sympathetic drive by increasing the levels and catalytically active form of nNOS by abrogating changes in the PIN in the PVN of CHF rats. CHF was induced in adult male Sprague-Dawley rats by coronary artery ligation, which reliably mimics CHF in patients with myocardial infarction. After 4 weeks of surgery, Sham and CHF rats were subjected to 3 weeks of progressive treadmill exercise. ExT significantly (p < 0.05) decreased PIN expression and increased dimer/monomer ratio of nNOS in the PVN of rats with CHF. Moreover, we found decreased GTP cyclohydrolase 1(GCH1) expression: a rate-limiting enzyme for BH4 biosynthesis in the PVN of CHF rats suggesting that perhaps reduced BH4 availability may also contribute to decreased nNOS dimers. Interestingly, CHF induced decrease in GCH1 expression was increased with ExT. Our findings revealed that ExT rectified decreased PIN and GCH1 expression and increased dimer/monomer ratio of nNOS in the PVN, which may lead to increase NO• bioavailability resulting in amelioration of activated sympathetic drive during CHF.
  • Hong Zheng, Kenichi Katsurada, Xuefei Liu, Mark M Knuepfer, Kaushik P Patel
    Hypertension (Dallas, Tex. : 1979) 72 3 667 - 675 2018年09月 [査読有り][通常論文]
     
    Renal denervation (RDN) has been shown to restore endogenous neuronal nitric oxide synthase (nNOS) in the paraventricular nucleus (PVN) and reduce sympathetic drive during chronic heart failure (CHF). The purpose of the present study was to assess the contribution of afferent renal nerves to the nNOS-mediated sympathetic outflow within the PVN in rats with CHF. CHF was induced in rats by ligation of the left coronary artery. Four weeks after surgery, selective afferent RDN (A-RDN) was performed by bilateral perivascular application of capsaicin on the renal arteries. Seven days after intervention, nNOS protein expression, nNOS immunostaining signaling, and diaphorase-positive stained cells were significantly decreased in the PVN of CHF rats, changes that were reversed by A-RDN. A-RDN reduced basal lumbar sympathetic nerve activity in rats with CHF (8.5%±0.5% versus 17.0%±1.2% of max). Microinjection of nNOS inhibitor L-NMMA (L-NG-monomethyl arginine citrate) into the PVN produced a blunted increase in lumbar sympathetic nerve activity in rats with CHF. This response was significantly improved after A-RDN (Δ lumbar sympathetic nerve activity: 25.7%±2.4% versus 11.2%±0.9%). Resting afferent renal nerves activity was substantially increased in CHF compared with sham rats (56.3%±2.4% versus 33.0%±4.7%). These results suggest that intact afferent renal nerves contribute to the reduction of nNOS in the PVN. A-RDN restores nNOS and thus attenuates the sympathoexcitation. Also, resting afferent renal nerves activity is elevated in CHF rats, which may highlight a crucial neural mechanism arising from the kidney in the maintenance of enhanced sympathetic drive in CHF.
  • Kenichi Katsurada, Toshihiko Yada
    Journal of diabetes investigation 7 Suppl 1 64 - 9 2016年04月 [査読有り][通常論文]
     
    Glucagon-like peptide-1 (GLP-1) is derived from both the enteroendocrine L cells and preproglucagon-expressing neurons in the nucleus tractus solitarius (NTS) of the brain stem. As GLP-1 is cleaved by dipeptidyl peptidase-4 yielding a half-life of less than 2 min, it is plausible that the gut-derived GLP-1, released postprandially, exerts its effects on the brain mainly by interacting with vagal afferent neurons located at the intestinal or hepatic portal area. GLP-1 neurons in the NTS widely project in the central nervous system and act as a neurotransmitter. One of the physiological roles of brain-derived GLP-1 is restriction of feeding. GLP-1 receptor agonists have recently been used to treat type 2 diabetic patients, and have been shown to exhibit pleiotropic effects beyond incretin action, which involve brain functions. GLP-1 receptor agonist administered in the periphery is stable because of its resistance to dipeptidyl peptidase-4, and is highly likely to act on the brain by passing through the blood-brain barrier (BBB), as well as interacting with vagal afferent nerves. Central actions of GLP-1 have various roles including regulation of feeding, weight, glucose and lipid metabolism, cardiovascular functions, cognitive functions, and stress and emotional responses. In the present review, we focus on the source of GLP-1 and the pathway by which peripheral GLP-1 informs the brain, and then discuss recent findings on the central effects of GLP-1 and GLP-1 receptor agonists.
  • Yusaku Iwasaki, Yuko Maejima, Shigetomo Suyama, Masashi Yoshida, Takeshi Arai, Kenichi Katsurada, Parmila Kumari, Hajime Nakabayashi, Masafumi Kakei, Toshihiko Yada
    American journal of physiology. Regulatory, integrative and comparative physiology 308 5 R360-9  2015年03月 [査読有り][通常論文]
     
    Oxytocin (Oxt), a neuropeptide produced in the hypothalamus, is implicated in regulation of feeding. Recent studies have shown that peripheral administration of Oxt suppresses feeding and, when infused subchronically, ameliorates hyperphagic obesity. However, the route through which peripheral Oxt informs the brain is obscure. This study aimed to explore whether vagal afferents mediate the sensing and anorexigenic effect of peripherally injected Oxt in mice. Intraperitoneal Oxt injection suppressed food intake and increased c-Fos expression in nucleus tractus solitarius to which vagal afferents project. The Oxt-induced feeding suppression and c-Fos expression in nucleus tractus solitarius were blunted in mice whose vagal afferent nerves were blocked by subdiaphragmatic vagotomy or capsaicin treatment. Oxt induced membrane depolarization and increases in cytosolic Ca(2+) concentration ([Ca(2+)]i) in single vagal afferent neurons. The Oxt-induced [Ca(2+)]i increases were markedly suppressed by Oxt receptor antagonist. These Oxt-responsive neurons also responded to cholecystokinin-8 and contained cocaine- and amphetamine-regulated transcript. In obese diabetic db/db mice, leptin failed to increase, but Oxt increased [Ca(2+)]i in vagal afferent neurons, and single or subchronic infusion of Oxt decreased food intake and body weight gain. These results demonstrate that peripheral Oxt injection suppresses food intake by activating vagal afferent neurons and thereby ameliorates obesity in leptin-resistant db/db mice. The peripheral Oxt-regulated vagal afferent neuron provides a novel target for treating hyperphagia and obesity.
  • Yuko Maejima, Kazuya Sakuma, Putra Santoso, Darambazar Gantulga, Kenichi Katsurada, Yoichi Ueta, Yuichi Hiraoka, Katsuhiko Nishimori, Shigeyasu Tanaka, Kenju Shimomura, Toshihiko Yada
    FEBS letters 588 23 4404 - 12 2014年11月 [査読有り][通常論文]
     
    Intracerebroventricular injection of oxytocin (Oxt), a neuropeptide produced in hypothalamic paraventricular (PVN) and supraoptic nuclei (SON), melanocortin-dependently suppresses feeding. However, the underlying neuronal pathway is unclear. This study aimed to determine whether Oxt regulates propiomelanocortin (POMC) neurons in the arcuate nucleus (ARC) of the hypothalamus. Intra-ARC injection of Oxt decreased food intake. Oxt increased cytosolic Ca(2+) in POMC neurons isolated from ARC. ARC POMC neurons expressed Oxt receptors and were contacted by Oxt terminals. Retrograde tracer study revealed the projection of PVN and SON Oxt neurons to ARC. These results demonstrate the novel oxytocinergic signaling from PVN/SON to ARC POMC, possibly regulating feeding.
  • Kenichi Katsurada, Yuko Maejima, Masanori Nakata, Misato Kodaira, Shigetomo Suyama, Yusaku Iwasaki, Kazuomi Kario, Toshihiko Yada
    Biochemical and biophysical research communications 451 2 276 - 81 2014年08月 [査読有り][通常論文]
     
    Glucagon-like peptide-1 (GLP-1) receptor agonists have been used to treat type 2 diabetic patients and shown to reduce food intake and body weight. The anorexigenic effects of GLP-1 and GLP-1 receptor agonists are thought to be mediated primarily via the hypothalamic paraventricular nucleus (PVN). GLP-1, an intestinal hormone, is also localized in the nucleus tractus solitarius (NTS) of the brain stem. However, the role of endogenous GLP-1, particularly that in the NTS neurons, in feeding regulation remains to be established. The present study examined whether the NTS GLP-1 neurons project to PVN and whether the endogenous GLP-1 acts on PVN to restrict feeding. Intra-PVN injection of GLP-1 receptor antagonist exendin (9-39) increased food intake. Injection of retrograde tracer into PVN combined with immunohistochemistry for GLP-1 in NTS revealed direct projection of NTS GLP-1 neurons to PVN. Moreover, GLP-1 evoked Ca(2+) signaling in single neurons isolated from PVN. The majority of GLP-1-responsive neurons were immunoreactive predominantly to corticotropin-releasing hormone (CRH) and nesfatin-1, and less frequently to oxytocin. These results indicate that endogenous GLP-1 targets PVN to restrict feeding behavior, in which the projection from NTS GLP-1 neurons and activation of CRH and nesfatin-1 neurons might be implicated. This study reveals a neuronal basis for the anorexigenic effect of endogenous GLP-1 in the brain.
  • Kenichi Katsurada, Masaru Ichida, Masako Sakuragi, Megumi Takehara, Yasuo Hozumi, Kazuomi Kario
    SpringerPlus 3 620 - 620 2014年 [査読有り][通常論文]
     
    The humanized monoclonal antibody trastuzumab has been in routine use for chemotherapy for human epidermal growth factor receptor II (HER2)-positive breast cancer. A major adverse effect of trastuzumab is cardiotoxicity. Well-established biomarkers or echocardiographic parameters to predict trastuzumab-induced cardiotoxicity have not yet been determined. We attempted to identify useful biomarkers and/or echocardiographic parameters to predict trastuzumab-induced cardiotoxicity. We prospectively investigated the cases of 19 women who received chemotherapy including anthracyclines and trastuzumab for HER2-positive breast cancer. We measured cardiac biomarkers and echocardiographic parameters before their chemotherapy and every 3 months up to 15 months until the end of the adjuvant trastuzumab therapy. We divided the patients into two groups: group R was the nine patients who showed a reduction of left ventricular ejection fraction (LVEF) ≥5%, and group N was the 10 patients who showed a reduction of LVEF <5%. The high-sensitivity troponin T (hs-TnT) level at 6 months was significantly higher in group R than in group N (11.0 ± 7.8 pg/mL vs. 4.0 ± 1.4 pg/mL, p < 0.01). The hs-TnT level with a cutoff value of 5.5 pg/mL at 6 months had 78% sensitivity and 80% specificity for predicting a reduction of LVEF at 15 months. In our evaluation of echocardiographic parameters at baseline, the diastolic function was more impaired in group R than in group N. The hs-TnT and echocardiographic parameters of diastolic function could be useful to predict trastuzumab-induced cardiotoxicity.
  • Masaru Ichida, Kenichi Katsurada, Takahiro Komori, Jun Matsumoto, Akihide Ohkuchi, Akio Izumi, Shigeki Matsubara, Takeshi Mitsuhashi, Kazuomi Kario
    Journal of cardiology cases 2 1 e28-e31  2010年08月 [査読有り][通常論文]
     
    Peripartum cardiomyopathy (PPCM) is a rare but potentially life-threatening disorder that occurs in late pregnancy or the early puerperium despite optimal medical therapy. Recently, oxidative stress-mediated generation of antiangiogenic and proapoptotic 16-kDa prolactin, and subsequent impaired cardiac microvascularization have been related to PPCM. In turn, prolactin blockade with bromocriptine has been proven successful in preventing the onset of PPCM in mice and in patients at high risk for the disease. Here, we report the efficacy of bromocriptine for treatment of a patient with PPCM.

MISC

受賞

  • 2019年10月 Second Prize for Poster Presentation in the Postdoctoral Fellow Category at the Midlands Society of Physiological Sciences 2019
     Role of the renal nerves in regulating GLP-1 mediated diuresis and natriuresis in rats with heart failure 
    受賞者: Kenichi Katsurada
  • 2018年09月 New Investigator Award for Japanese Fellowship at Joint Hypertension Scientific Sessions 2018
     Selective renal afferent denervation enhances diuretic and natriuretic response to Glucagon-like peptide-1 in rats with heart failure 
    受賞者: Kenichi Katsurada
  • 2016年03月 Japan Heart Foundation 第29回日本心臓財団・バイエル薬品海外留学助成金
     視床下部-脳幹-腎神経連関による循環調節機構の解明と高血圧・心不全治療への応用 
    受賞者: 桂田健一
  • 2015年07月 Best Poster Presentation at Incretin 2015 Conference
     GLP-1 neurons in the nucleus tractus solitarius project to paraventricular nucleus and suppress feeding 
    受賞者: Kenichi Katsurada
  • 2014年04月 自治医科大学大学院医学研究科研究奨励賞
     糖尿病治療薬GLP-1受容体アゴニストの中枢神経を介した心血管作用 
    受賞者: 桂田健一
  • 2013年04月 自治医科大学大学院医学研究科若手スタートアップ研究費
     糖尿病治療薬GLP-1・DPP-4阻害薬の中枢神経を介した心血管保護作用 
    受賞者: 桂田健一

共同研究・競争的資金等の研究課題

  • 交感神経-SGLT2連関の解明と心不全治療への応用
    日本学術振興会:科学研究費助成事業 若手研究
    研究期間 : 2021年04月 -2024年03月 
    代表者 : 桂田 健一

委員歴

  • 2020年10月 - 現在   日本高血圧学会   国際委員会


Copyright © MEDIA FUSION Co.,Ltd. All rights reserved.