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Purpose:Few studies have investigated prognostic biomarkers in patients with intrahepatic cholangiocarcinoma (ICC). Nardilysin (NRDC), a metalloendopeptidase of the M16 family, has been suggested to play important roles in inflammation and several cancer types. We herein examined the clinical significance and biological function of NRDC in ICC.Experimental Design: We measured serum NRDC levels in 98 patients with ICC who underwent surgical resection in two independent cohorts to assess its prognostic impact. We also analyzed NRDC mRNA levels in cancerous tissue specimens from 43 patients with ICC. We investigated the roles of NRDC in cell proliferation, migration, gemcitabine sensitivity, and gene expression in ICC cell lines using gene silencing.Results:High serum NRDC levels were associated with shorter overall survival and disease-free survival in the primary (n = 79) and validation (n = 19) cohorts. A correlation was observed between serum protein levels and cancerous tissue mRNA levels of NRDC (Spearman ρ = 0.413; P = 0.006). The gene knockdown of NRDC in ICC cell lines attenuated cell proliferation, migration, and tumor growth in xenografts, and increased sensitivity to gemcitabine. The gene knockdown of NRDC was also accompanied by significant changes in the expression of several epithelial–mesenchymal transition (EMT)-related genes. Strong correlations were observed between the mRNA levels of NRDC and EMT-inducing transcription factors, ZEB1 and SNAI1, in surgical specimens from patients with ICC.Conclusions:Serum NRDC, a possible surrogate marker reflecting the EMT state in primary tumors, predicts the outcome of ICC after surgical resection.

Supplementary Tables S1-S7; Supplementary Figures S1-S7

Nardilysin (NRDC) has been shown to be involved in post-translational histone modifications, in addition to enhancement in ectodomain shedding of membrane-anchored protein, which play significant roles in various pathophysiology, including glucose homeostasis, inflammatory diseases and cancer. The present study sought to determine roles of NRDC in the liver on lipid and lipoprotein metabolism. We established liver-specific NRDC deficient mice by use of NRD1 floxed mice and albumin promoter-Cre recombinase (Cre) transgenic mice, and found that their serum low-density lipoprotein (LDL) cholesterol levels were significantly lower than those in control littermate mice. In the liver, LDL receptor (LDLR) mRNA expression was significantly upregulated, while inducible degrader of LDLR (IDOL) and microsomal triglyceride transfer protein (MTP) mRNA expression was significantly downregulated, in liver-specific NRDC deficient mice. Hepatic cell-surface LDLR expression levels were significantly elevated and serum pro-protein convertase subtilisin-kexin type 9 (PCSK9) levels were significantly reduced in mice with hepatic NRDC deficiency. In cultured hepatocytes, NRDC deficiency significantly reduced secreted PCSK9 and increased cell-surface LDLR expression. On the other hand, NRDC overexpression in cultured hepatocytes significantly increased secreted PCSK9 and lowered cell-surface LDLR expression. Thus, NRDC in murine hepatocytes appears to play key roles in cholesterol homeostasis, although the precise molecular mechanisms remain to be determined.

Cardiac sympathetic innervation is critically involved in the regulation of circulatory dynamics. However, the molecular mechanism for the innervation patterning has remained elusive. Here, we demonstrate that nardilysin (NRDC, Nrdc), an enhancer of ectodomain shedding, regulates cardiac sympathetic innervation. Nardilysin-deficient (Nrdc-/- ) mice show hypoplastic hearts, hypotension, bradycardia, and abnormal sympathetic innervation patterning. While the innervation of left ventricle (LV) of wild-type mice is denser in the subepicardium than in the subendocardium, Nrdc-/- LV lacks such a polarity and is uniformly and more abundantly innervated. At the molecular level, the full-length form of p75 neurotrophin receptor (p75NTR , Ngfr) is increased in Nrdc-/- LV due to the reduced ectodomain shedding of p75NTR . Importantly, the reduction of p75NTR rescued the abnormal innervation phenotype of Nrdc-/- mice. Moreover, sympathetic neuron-specific, but not cardiomyocyte-specific deletion of Nrdc recapitulated the abnormal innervation patterning of Nrdc-/- mice. In conclusion, neuronal nardilysin critically regulates cardiac sympathetic innervation and circulatory dynamics via modulation of p75NTR .

Background: Increased fatty acid oxidation (FAO) has long been considered a culprit in the development of obesity/diabetes mellitus–induced cardiomyopathy. However, enhancing cardiac FAO by removing the inhibitory mechanism of long-chain fatty acid transport into mitochondria via deletion of acetyl coenzyme A carboxylase 2 (ACC2) does not cause cardiomyopathy in nonobese mice, suggesting that high FAO is distinct from cardiac lipotoxicity. We hypothesize that cardiac pathology–associated obesity is attributable to the imbalance of fatty acid supply and oxidation. Thus, we here seek to determine whether further increasing FAO by inducing ACC2 deletion prevents obesity-induced cardiomyopathy, and if so, to elucidate the underlying mechanisms. Methods: We induced high FAO in adult mouse hearts by cardiac-specific deletion of ACC2 using a tamoxifen-inducible model (ACC2 iKO). Control and ACC2 iKO mice were subjected to high-fat diet (HFD) feeding for 24 weeks to induce obesity. Cardiac function, mitochondria function, and mitophagy activity were examined. Results: Despite both control and ACC2 iKO mice exhibiting a similar obese phenotype, increasing FAO oxidation by deletion of ACC2 prevented HFD-induced cardiac dysfunction, pathological remodeling, and mitochondria dysfunction, as well. Similarly, increasing FAO by knockdown of ACC2 prevented palmitate-induced mitochondria dysfunction and cardiomyocyte death in vitro. Furthermore, HFD suppressed mitophagy activity and caused damaged mitochondria to accumulate in the heart, which was attenuated, in part, in the ACC2 iKO heart. Mechanistically, ACC2 iKO prevented HFD-induced downregulation of parkin. During stimulation for mitophagy, mitochondria-localized parkin was severely reduced in control HFD-fed mouse heart, which was restored, in part, in ACC2 iKO HFD-fed mice. Conclusions: These data show that increasing cardiac FAO alone does not cause cardiac dysfunction, but protects against cardiomyopathy in chronically obese mice. The beneficial effect of enhancing cardiac FAO in HFD-induced obesity is mediated, in part, by the maintenance of mitochondria function through regulating parkin-mediated mitophagy. Our findings also suggest that targeting the parkin-dependent mitophagy pathway could be an effective strategy against the development of obesity-induced cardiomyopathy.

Purpose: Few studies have investigated prognostic biomarkers in patients with intrahepatic cholangiocarcinoma (ICC). Nardilysin (NRDC), a metalloendopeptidase of the M16 family, has been suggested to play important roles in inflammation and several cancer types. We herein examined the clinical significance and biological function of NRDC in ICC. Experimental Design: We measured serum NRDC levels in 98 patients with ICC who underwent surgical resection in two independent cohorts to assess its prognostic impact. We also analyzed NRDC mRNA levels in cancerous tissue specimens from 43 patients with ICC. We investigated the roles of NRDC in cell proliferation, migration, gemcitabine sensitivity, and gene expression in ICC cell lines using gene silencing. Results: High serum NRDC levels were associated with shorter overall survival and disease-free survival in the primary (n = 79) and validation (n = 19) cohorts. A correlation was observed between serum protein levels and cancerous tissue mRNA levels of NRDC (Spearman ρ = 0.413; P = 0.006). The gene knockdown of NRDC in ICC cell lines attenuated cell proliferation, migration, and tumor growth in xenografts, and increased sensitivity to gemcitabine. The gene knockdown of NRDC was also accompanied by significant changes in the expression of several epithelial–mesenchymal transition (EMT)-related genes. Strong correlations were observed between the mRNA levels of NRDC and EMT-inducing transcription factors, ZEB1 and SNAI1, in surgical specimens from patients with ICC. Conclusions: Serum NRDC, a possible surrogate marker reflecting the EMT state in primary tumors, predicts the outcome of ICC after surgical resection.

Post-translational histone modifications, such as acetylation and methylation, are prerequisites for transcriptional regulation. The metalloendopeptidase nardilysin (Nrdc) is a H3K4me2-binding protein that controls thermoregulation and β-cell functions through its transcriptional coregulator function. We herein combined high-throughput ChIP-seq and RNA-seq to achieve the first genome-wide identification of Nrdc target genes. A ChIP-seq analysis of immortalized mouse embryo fibroblasts (iMEF) identified 4053 Nrdc-binding sites, most of which were located in proximal promoter sites (2587 Nrdc-binding genes). Global H3K4me2 levels at Nrdc-binding promoters slightly increased, while H3K9ac levels decreased in the absence of Nrdc. Among Nrdc-binding genes, a comparative RNA-seq analysis identified 448 candidates for Nrdc target genes, among which cell cycle-related genes were significantly enriched. We confirmed decreased mRNA and H3K9ac levels at the promoters of individual genes in Nrdc-deficient iMEF, which were restored by the ectopic introduction of Nrdc. Reduced mRNA levels, but not H3K9ac levels were fully restored by the reintroduction of the peptidase-dead mutant of Nrdc. Furthermore, Nrdc promoted cell cycle progression at multiple stages, which enhanced cell proliferation in vivo. Collectively, our integrative studies emphasize the importance of Nrdc for maintaining a proper epigenetic status and cell growth.

Background Biomarkers for detection of transient myocardial ischemia in patients with unstable angina (UA) or for very early diagnosis of acute myocardial infarction (AMI) are not currently available. Methods and results We performed two sequential screenings of autoantibodies elevated shortly after the onset of acute coronary syndrome (ACS), and focused on metalloendopeptidase nardilysin (NRDC) among 19 identified candidate antigens. In a retrospective analysis among 93 ACS and 117 non-ACS patients, the serum level of NRDC was significantly increased in patients with ACS compared with that in patients with non-ACS (2073.5±189.8pg/ml versus 775.7±63.4pg/ml, P N =35 and UA: N =8), serum concentration of NRDC was significantly increased even in UA patients with a peak serum NRDC levels reached at admission both in AMI and UA patients. In a mouse model of AMI, we found an acute increase in serum NRDC and reduced NRDC expression in ischemic regions shortly after coronary artery ligation. NRDC expression was also reduced in infarcted regions in human autopsy samples from AMI patients. Moreover, the short treatment of primary culture of rat cardiomyocytes with H 2 O 2 or A23187 induced NRDC secretion without cell toxicity. Conclusion NRDC is a promising biomarker for the early detection of ACS, even in UA patients without elevation of necrosis markers.

Nardilysin (NRDC) is a metalloendopeptidase of the M16 family. We previously showed that NRDC activates inflammatory cytokine signaling, including interleukin‐6‐signal transducer and activator of transcription 3 (STAT3) signaling. NRDC has been implicated in the promotion of breast, gastric and esophageal cancer, as well as the development of liver fibrosis. In this study, we investigated the role of NRDC in the promotion of hepatocellular carcinoma (HCC), both clinically and experimentally. We found that NRDC expression was upregulated threefold in HCC tissue compared to the adjacent non‐tumor liver tissue, which was confirmed by immunohistochemistry and western blotting. We also found that high serum NRDC was associated with large tumor size (>3 cm, P = 0.016) and poor prognosis after hepatectomy (median survival time 32.0 vs 73.9 months, P = 0.003) in patients with hepatitis C (n = 120). Diethylnitrosamine‐induced hepatocarcinogenesis was suppressed in heterozygous NRDC‐deficient mice compared to their wild‐type littermates. Gene silencing of NRDC with miRNA diminished the growth of Huh‐7 and Hep3B spheroids in vitro. Notably, phosphorylation of STAT3 was decreased in NRDC‐depleted Huh‐7 spheroids compared to control spheroids. The effect of a STAT3 inhibitor (S3I‐201) on the growth of Huh‐7 spheroids was reduced in NRDC‐depleted cells relative to controls. Our results show that NRDC is a promising prognostic marker for HCC in patients with hepatitis C, and that NRDC promotes tumor growth through activation of STAT3.

Inflammation resulting from virus infection is the cause of myocarditis; however, the precise mechanism by which inflammation induces cardiac dysfunction is still unclear. In this study, we investigated the contribution of insulin signalling to inflammatory cardiac dysfunction induced by the activation of signalling by NF-κB, a major transcriptional factor regulating inflammation. We generated mice constitutively overexpressing kinase-active IKK-β, an essential kinase for NF-κB activation, in cardiomyocytes (KA mice). KA mice demonstrated poor survival and significant cardiac dysfunction with remarkable dilation. Histologically, KA hearts revealed increased cardiac apoptosis and fibrosis and the enhanced recruitment of immune cells. By molecular analysis, we observed the increased phosphorylation of IRS-1, indicating the suppression of insulin signalling in KA hearts. To evaluate the contribution of insulin signalling to cardiac dysfunction in KA hearts, we generated mice with cardiac-specific suppression of phosphatase and tensin homologue 10 (PTEN), a negative regulator of insulin signalling, in the KA mouse background (KA-PTEN). The suppression of PTEN successfully improved insulin signalling in KA-PTEN hearts, and interestingly, KA-PTEN mice showed significantly improved cardiac function and survival. These results indicated that impaired insulin signalling underlies the mechanism involved in inflammation-induced cardiac dysfunction, which suggests that it may be a target for the treatment of myocarditis.

Nardilysin (NRDC; N-arginine dibasic convertase) is a metalloprotease of the M16 family. We have demonstrated that NRDC in the extracellular space enhances ectodomain cleavage of multiple membrane proteins. We also reported that nuclear NRDC regulates transcription of several target genes as a transcriptional coregulator. These results indicated that NRDC is a protease having localization-dependent multiple functions. NRDC-deficient mice (Nrdc−/−) showed wide range of phenotypes such as hypomyelination, hypothermia, and bradycardia. In this study, we have explored a role of NRDC in the regulation of heart rate. (1) Pharmacological blocking of autonomic nervous system revealed that an intrinsic heart rate of Nrdc−/− was significantly reduced compared with that of wild-type mice. (2) In Nrdc−/− hearts, mRNA levels of Cav3.1 and HCN1/4, ion channels responsible for sinus automaticity, were significantly reduced. (3) Funny (If) current and T-type Ca current measured in the sinus node cells were markedly reduced in Nrdc−/− cells, indicating that the functions of Cav3.1 and HCN4 are impaired. (4) Gene knockdown of NRDC in primary rat ventricular myocyte led to the reduction of mRNA level of HCN4. (5) Chromatin immunoprecipitation-PCR analysis showed that NRDC binds to the promoter region of Cav3.1 and HCN4, suggesting the direct involvement of NRDC in transcriptional regulation of these ion channels. (6) Atrium-specific Nrdc−/− (Sarcolipin-Cre) showed mild bradycardia and reduced Cav3.1 mRNA expression. Together, our results indicated that NRDC in cardiomyocyte controls heart rate through the transcriptional regulation of ion channels critical for sinus automaticity. Acknowledgement/Funding KAKENHI (17K09575)

The rate limiting step of BCAA (Branched-chain amino acid; Valine, Leucine and Isoleucine) catabolism is regulated by the branched-chain keto acid dehydrogenase complex (BCKDC). PPM1K is a phosphatase which regulates BCAA catabolism by activating BCKDC through dephosphorylation. We and other groups have reported impaired BCAA catabolism and elevated blood BCAA levels in PPM1K-defiient mice (KO). Several studies have shown that elevated blood BCAA levels are associated with obesity and glucose intolerance. In addition, PPM1K expression is reduced in obesity model animals (leptin-deficient mice, etc.) and GWAS data shows loss-of-function SNP of PPM1K gene is associated with diabetes. Based on these findings, loss/reduction of PPM1K is thought to induce glucose intolerance. However, no previous study has directly analyzed the role of PPM1K in obesity and glucose metabolism. Therefore, in this study, we analyzed KO and wild type mice (WT) with diet-induced obesity. Firstly, KO and WT were fed with either normal chow diet (NCD) or high-fat diet (HFD; 60% of kcal from fat). KO showed normal body weight gain in both NCD and HFD condition. Next, KO and WT underwent intra-peritoneal glucose tolerance test (ipGTT). NCD-fed KO showed normal glucose tolerance. Surprisingly, HFD-fed KO showed significantly better glucose tolerance (AUC WT 58192±7828 vs. KO 47526±6646 min*mg/dL, p In summary, these results suggest the critical role of PPM1K and BCAA catabolism in the regulation of glucose homeostasis. Disclosure K. Nishi: None. L. Abell: None. T. McMillen: None. R. Tian: None. Funding Japan Heart Foundation; National Institutes of Health

Type 2 diabetes (T2D) is associated with pancreatic β-cell dysfunction, manifested by reduced glucose-stimulated insulin secretion (GSIS). Several transcription factors enriched in β-cells, such as MafA, control β-cell function by organizing genes involved in GSIS. Here we demonstrate that nardilysin (N-arginine dibasic convertase; Nrd1 and NRDc) critically regulates β-cell function through MafA. Nrd1−/− mice showed glucose intolerance and severely decreased GSIS. Islets isolated from Nrd1−/− mice exhibited reduced insulin content and impaired GSIS in vitro. Moreover, β-cell-specific NRDc-deficient (Nrd1delβ) mice showed a diabetic phenotype with markedly reduced GSIS. MafA was specifically downregulated in islets from Nrd1delβ mice, whereas overexpression of NRDc upregulated MafA and insulin expression in INS832/13 cells. Chromatin immunoprecipitation assay revealed that NRDc is associated with Islet-1 in the enhancer region of MafA, where NRDc controls the recruitment of Islet-1 and MafA transcription. Our findings demonstrate that NRDc controls β-cell function via regulation of the Islet-1–MafA pathway.

Colon cancer is a complex disease affected by a combination of genetic and epigenetic factors. Here we demonstrate that nardilysin (N-arginine dibasic convertase; NRDC), a metalloendopeptidase of the M16 family, regulates intestinal tumorigenesis via its nuclear functions. NRDC is highly expressed in human colorectal cancers. Deletion of the Nrdc gene in ApcMin mice crucially suppressed intestinal tumor development. In ApcMin mice, epithelial cell-specific deletion of Nrdc recapitulated the tumor suppression observed in Nrdc-null mice. Moreover, epithelial cell-specific overexpression of Nrdc significantly enhanced tumor formation in ApcMin mice. Notably, epithelial NRDC controlled cell apoptosis in a gene dosage-dependent manner. In human colon cancer cells, nuclear NRDC directly associated with HDAC1, and controlled both acetylation and stabilization of p53, with alterations of p53 target apoptotic factors. These findings demonstrate that NRDC is critically involved in intestinal tumorigenesis through its epigenetic regulatory function, and targeting NRDC may lead to a novel prevention or therapeutic strategy against colon cancer.

ObjectiveNardilysin (NRDC), a zinc peptidase, exhibits multiple localisation-dependent functions including as an enhancer of ectodomain shedding in the extracellular space and a transcriptional coregulator in the nucleus. In this study, we investigated its functional role in exocrine pancreatic development, homeostasis and the formation of pancreatic ductal adenocarcinoma (PDA).DesignWe analysedPtf1a-Cre; Nrdcflox/floxmice to investigate the impact ofNrdcdeletion. Pancreatic acinar cells were isolated fromNrdcflox/floxmice and infected with adenovirus expressing Cre recombinase to examine the impact ofNrdcinactivation. Global gene expression inNrdc-cKOpancreas was analysed compared with wild-type pancreas by microarray analysis. We also analysedPtf1a-Cre; KrasG12D; Nrdcflox/floxmice to investigate the impact ofNrdcdeletion in the context of oncogenic Kras. A total of 51 human samples of pancreatic intraepithelial lesions (PanIN) and PDA were examined by immunohistochemistry for NRDC.ResultsWe found that pancreatic deletion ofNrdcleads to spontaneous chronic pancreatitis concomitant with acinar-to-ductal conversion, increased apoptosis and atrophic pancreas in mice. Acinar-to-ductal conversion was observed mainly through a non-cell autonomous mechanism, and the expression of several chemokines was significantly increased inNrdc-null pancreatic acinar cells. Furthermore, pancreatic deletion ofNrdcdramatically acceleratedKrasG12D-driven PanIN and subsequent PDA formation in mice. These data demonstrate a previously unappreciated anti-inflammatory and tumour suppressive functions of Nrdc in the pancreas in mice. Finally, absence of NRDC expression was observed in a subset of human PanIN and PDA.ConclusionNrdc inhibits pancreatitis and suppresses PDA initiation in mice.

Summary Background The ambulatory treatment of advanced heart failure (HF) with intermittent infusions of inotropes or natriuretic peptide chosen immediately before each infusion has not been described. Methods Between May 2005 and July 2009, we treated 11 patients presenting with advanced HF, who received a total of 369 infusions of carperitide, olprinone, dopamine, or dobutamine, once or twice weekly. The pharmaceutical was selected before each infusion based on the systolic blood pressure (BP). Results Carperitide, olprinone, and catecholamines were administered to 8 (73 infusions of 0.030 ± 0.004 μg/kg/min for 3.3 ± 0.8 h), 4 (18 infusions of 0.070 ± 0.017 μg/kg/min for 3.3 ± 0.5 h), and 6 patients (278 infusions of 3.6 ± 1.9 μg/kg/min for 2.8 ± 1.0 h), respectively. No adverse effect requiring cessation of infusion was observed. Over a mean follow-up of 29.3 ± 28.8 months (range 2–104), 4 patients died, all from cardiac causes. The Kaplan–Meier cumulative survival rate was 69.3% at 20 months (median follow-up). Compared with the pre-infusion period, the duration and number of hospitalizations for management of HF were decreased by 73.9% ( p = 0.017), and 51.9% ( p = 0.007), respectively, during the treatment period, and the overall medical costs by 56.9% ( p = 0.021). Conclusions In this study population, intermittent drug infusions selected from inotropes or natriuretic peptide based on the baseline systolic BP significantly decreased the length and number of hospitalizations and costs, without increasing mortality. These results indicate that intermittent infusions might be one of the therapeutic options in advanced HF.

Objective: Tumour necrosis factor alpha (TNF-α) plays an important role in rheumatoid arthritis (RA). TNF-α is synthesised as a membrane-anchored precursor and is fully activated by a disintegrin and metalloproteinase 17 (ADAM17)-mediated ectodomain shedding. Nardilysin (NRDC) facilitates ectodomain shedding via activation of ADAM17. This study was undertaken to elucidate the role of NRDC in RA. Methods: NRDC-deficient (Nrdc–/– ) mice and macrophage-specific NRDC-deficient (NrdcdelM ) mice were examined in murine RA models, collagen antibody-induced arthritis (CAIA) and K/BxN serum transfer arthritis (K/BxN STA). We evaluated the effect of gene deletion or silencing of Nrdc on ectodomain shedding of TNF-α in macrophages or monocytes. NRDC concentration in synovial fluid from patients with RA and osteoarthritis (OA) were measured. We also examined whether local gene silencing of Nrdc ameliorated CAIA. Results: CAIA and K/BxN STA were significantly attenuated in Nrdc–/– mice and NrdcdelM mice. Gene deletion or silencing of Nrdc in macrophages or THP-1 cells resulted in the reduction of TNF-α shedding. The level of NRDC is higher in synovial fluid from RA patients compared with that from OA patients. Intra-articular injection of anti-Nrdcsmall interfering RNA ameliorated CAIA. Conclusion: These data indicate that NRDC plays crucial roles in the pathogenesis of autoimmune arthritis and could be a new therapeutic target for RA treatment., 新たな関節リウマチ治療のターゲット分子としてのナルディライジン. 京都大学プレスリリース. 2017-07-11.

Body temperature homoeostasis in mammals is governed centrally through the regulation of shivering and non-shivering thermogenesis and cutaneous vasomotion. Non-shivering thermogenesis in brown adipose tissue (BAT) is mediated by sympathetic activation, followed by PGC-1α induction, which drives UCP1. Here we identify nardilysin (Nrd1 and NRDc) as a critical regulator of body temperature homoeostasis. Nrd1(-/-) mice show increased energy expenditure owing to enhanced BAT thermogenesis and hyperactivity. Despite these findings, Nrd1(-/-) mice show hypothermia and cold intolerance that are attributed to the lowered set point of body temperature, poor insulation and impaired cold-induced thermogenesis. Induction of β3-adrenergic receptor, PGC-1α and UCP1 in response to cold is severely impaired in the absence of NRDc. At the molecular level, NRDc and PGC-1α interact and co-localize at the UCP1 enhancer, where NRDc represses PGC-1α activity. These findings reveal a novel nuclear function of NRDc and provide important insights into the mechanism of thermoregulation., 「体温恒常性維持のメカニズムの解明」に成功. 京都大学プレスリリース. 2014-02-04.

Amyloid beta (Aβ) peptide, the main component of senile plaques in patients with Alzheimer's disease (AD), is derived from proteolytic cleavage of amyloid precursor protein (APP) by β- and γ-secretases. Alpha-cleavage of APP by α-secretase has a potential to preclude the generation of Aβ because it occurs within the Aβ domain. We previously reported that a metalloendopeptidase, nardilysin (N-arginine dibasic convertase; NRDc) enhances α-cleavage of APP, which results in the decreased generation of Aβ in vitro. To clarify the in vivo role of NRDc in AD, we intercrossed transgenic mice expressing NRDc in the forebrain with an AD mouse model. Here we demonstrate that the neuron-specific overexpression of NRDc prevents Aβ deposition in the AD mouse model. The activity of α-secretase in the mouse brain was enhanced by the overexpression of NRDc, and was reduced by the deletion of NRDc. However, reactive gliosis adjacent to the Aβ plaques, one of the pathological features of AD, was not affected by the overexpression of NRDc. Taken together, our results indicate that NRDc controls Aβ formation through the regulation of α-secretase.

To determine whether drug infusions at ambulatory clinic in patients with end stage congestive heart failure are safe and reduce the period of hospitalization.Between May 2000 and November 2006, 21 ambulatory patients with end stage congestive heart failure were treated with infusions of the natriuretic peptide, carperitide (6 patients, 43 infusions of mean 0.033 microg/kg/min for mean 3.7 hr), the phosphodiesterase inhibitor, olprinone (19 patients, 75 infusions of mean 0.11 microg/kg/min for mean 3.8 hr), or the catecholamines, dopamine or dobutamine(5 patients, 89 infusions of mean 3.3 microg/kg/min for mean 3.2 hr).Systolic and diastolic blood pressure was lower after infusion of carperitide, whereas catecholamines increased systolic blood pressure and heart rate (all differences from baseline p0.0001). Olprinone changed neither blood pressure nor heart rate. No adverse effect was observed, including arrhythmias or change in blood pressure requiring cessation of drug infusion. Mean urinary output per infusion was 979 ml for carperitide, 720ml for olprinone, and 594ml for catecholamines. There was no correlation between mean urinary output and dose of furosemide administered during intermittent infusion therapy. There was a close correlation between pre-infusion blood pressure and urinary output(systolic: p0.05; diastolic: p0.0001). Infusion therapy reduced the length of hospitalization (p0.05) in 7 patients from April 2005.Ambulatory, low-dose infusion therapy may not decrease the mortality of patients in end-stage congestive heart failure, but was safe and might represent an acceptable end-of-life therapeutic option.