Nardilysin Is Required for Maintaining Pancreatic β-Cell Function

Nardilysin in vascular smooth muscle cells controls blood pressure via the regulation of calcium dynamics

Blood pressure is a crucial physiological parameter and its abnormalities can cause a variety of health problems. We have previously reported that mice with systemic deletion of nardilysin (NRDC), an M16 family metalloprotease, exhibit hypotension. In this study, we aimed to clarify the role of NRDC in vascular smooth muscle cell (VSMC) by generating VSMC-specific Nrdc knockout (VSMC-KO) mice. Our findings reveal that VSMC-KO mice also exhibit hypotension. Aortas isolated from VSMC-KO mice exhibited a weakened contractile response to phenylephrine, accompanied by reduced phosphorylation of myosin light chain 2 and decreased rhoA expression. VSMC isolated from VSMC-KO aortas showed a reduced increase in intracellular Ca2+ concentration induced by α-stimulants. These findings suggest that NRDC in VSMC regulates vascular contraction and blood pressure by modulating Ca2+ dynamics.

Auxiliary roles of nardilysin in the early diagnosis of acute coronary syndrome: a prospective cohort study, the Nardi-ACS study

Acute coronary syndrome (ACS) includes myocardial infarction (MI) and unstable angina (UA). MI is defined by elevated necrosis markers, preferably high-sensitivity cardiac troponins (hs-cTn). However, it takes hours for cTn to become elevated after coronary occlusion; therefore, difficulties are associated with diagnosing early post-onset MI or UA. The aim of this prospective cohort study was to examine the diagnostic ability of serum nardilysin (NRDC) for the early detection of ACS. This study consisted of two sequential cohorts, the Phase I cohort, 435 patients presenting to the emergency room (ER) with chest pain, and the Phase II cohort, 486 patients with chest pain who underwent coronary angiography. The final diagnosis was ACS in 155 out of 435 patients (35.6%) in the phase I and 418 out of 486 (86.0%) in the phase II cohort. Among 680 patients who presented within 24 h of onset, 466 patients (68.5%) were diagnosed with ACS. Serum NRDC levels were significantly higher in patients with ACS than in those without ACS. The sensitivity of NRDC in patients who presented within 6 h after the onset was higher than that of hsTnI, and the AUC of NRDC within 1 h of the onset was higher than that of hsTnI (0.718 versus 0.633). Among hsTnI-negative patients (300 of 680 patients: 44.1%), 136 of whom (45.3%) were diagnosed with ACS, the sensitivity and the NPV of NRDC were 73.5 and 65.7%, respectively. When measured in combination with hsTnI, NRDC plays auxiliary roles in the early diagnosis of ACS.

Null mutation of exocyst complex component 3-like does not affect vascular development in mice

Exocyst is an octameric protein complex implicated in exocytosis. The exocyst complex is highly conserved among mammalian species, but the physiological function of each subunit in exocyst remains unclear. Previously, we identified exocyst complex component 3-like (Exoc3l) as a gene abundantly expressed in embryonic endothelial cells and implicated in the process of angiogenesis in human umbilical cord endothelial cells. Here, to reveal the physiological roles of Exoc3l during development, we generated Exoc3l knockout (KO) mice by genome editing with CRISPR/Cas9. Exoc3l KO mice were viable and showed no significant phenotype in embryonic angiogenesis or postnatal retinal angiogenesis. Exoc3l KO mice also showed no significant alteration in cholesterol homeostasis or insulin secretion, although several reports suggest an association of Exoc3l with these processes. Despite the implied roles, Exoc3l KO mice exhibited no apparent phenotype in vascular development, cholesterol homeostasis, or insulin secretion.

Nardilysin determines hematopoietic stem cell fitness by regulating protein synthesis

Nardilysin (NRDC) is a multifunctional protein required for maintaining homeostasis in various cellular and tissue contexts. However, its role in hematopoietic stem cells (HSCs) remains unclear. Here, through the conditional deletion of NRDC in hematopoietic cells, we demonstrate that NRDC is required for HSCs expansion in vitro and the reconstitution of hematopoiesis in vivo after transplantation. We found NRDC-deficient HSCs lose their self-renewal ability and display a preferential bias to myeloid differentiation in response to replication stress. Transcriptome data analysis revealed the upregulation of heat shock response-related genes in NRDC-deficient HSCs. Additionally, we observed increased protein synthesis in cultured NRDC-deficient HSCs. Thus, loss of NRDC may cause the inability to control protein synthesis in response to replication induced protein stress, leading to the impaired HSC self-renewal ability. This highlights a novel model of action of NRDC specifically in HSCs.

Immunohistochemical and clinicopathological study regarding nardilysin on extramammary Paget's disease

It has been reported that nardilysin (NRDC), a metalloendopeptidase which regulates various growth factors and cytokines, is associated with malignancies in a conflicting manner, in which it promoted gastric, hepatocellular, and colorectal cancers and suppressed pancreatic ductal adenocarcinoma. However, it has not been investigated how NRDC is associated with cutaneous malignancies for now. Immunohistochemical staining has revealed that NRDC expression is observed in all extramammary Paget's disease (EMPD) cases. Notably, other cutaneous malignancies including basal cell carcinoma, squamous cell carcinoma, and eccrine porocarcinoma, did not show increased NRDC expression in immunohistochemistry. EMPD typically presents several types of lesions including nodules, and positive staining of NRDC on EMPD was observed regardless of the type of lesions. Examination using samples taken from nodular lesions showed that some cases showed heterogenous NRDC expression within each lesion. We also found that NRDC staining was weaker in the marginal parts of EMPD lesion than in the central parts in several cases, and tumor cells tend to be distributed beyond the macroscopic skin lesions in these cases. It was speculated that decreased NRDC expression in the marginal zones of the skin lesions may be associated with the ability of tumor cells to produce the cutaneous manifestation of EMPD. This study suggests that NRDC may be associated with EMPD like other malignancies reported previously.

Branched-chain keto acids inhibit mitochondrial pyruvate carrier and suppress gluconeogenesis in hepatocytes

Branched-chain amino acid (BCAA) metabolism is linked to glucose homeostasis, but the underlying signaling mechanisms are unclear. We find that gluconeogenesis is reduced in mice deficient of Ppm1k, a positive regulator of BCAA catabolism, which protects against obesity-induced glucose intolerance. Accumulation of branched-chain keto acids (BCKAs) inhibits glucose production in hepatocytes. BCKAs suppress liver mitochondrial pyruvate carrier (MPC) activity and pyruvate-supported respiration. Pyruvate-supported gluconeogenesis is selectively suppressed in Ppm1k-deficient mice and can be restored with pharmacological activation of BCKA catabolism by BT2. Finally, hepatocytes lack branched-chain aminotransferase that alleviates BCKA accumulation via reversible conversion between BCAAs and BCKAs. This renders liver MPC most susceptible to circulating BCKA levels hence a sensor of BCAA catabolism.

Vascularized pancreas-on-a-chip device produced using a printable simulated extracellular matrix

The extracellular matrix (ECM) influences cellular behavior, function, and fate. The ECM surrounding Langerhans islets has not been investigated in detail to explain its role in the development and maturation of pancreatic β-cells. Herein, a complex combination of the simulated ECM (sECM) has been examined with a comprehensive analysis of cell response and a variety of controls. The most promising results were obtained from group containing fibrin, collagen type I, Matrigel®, hyaluronic acid, methylcellulose, and two compounds of functionalized, ionically crosslinking bacterial cellulose (sECMbc). Even though the cell viability was not significantly impacted, the performance of group of sECMbc showed 2 to 4x higher sprouting number and length, 2 to 4x higher insulin secretion in static conditions, and 2 to 10x higher gene expression of VEGF-A, Endothelin-1, and NOS3 than the control group of fibrin matrix (sECMf). Each material was tested in a hydrogel-based, perfusable, pancreas-on-a-chip device and the best group - sECMbc has been tested with the drug Sunitinib to show the extended possibilities of the device for both diabetes-like screening as well as PDAC chemotherapeutics screening for potential personal medicine approach. It proved its functionality in 7 days dynamic culture and is suitable as a physiological tissue model. Moreover, the device with the pancreatic-like spheroids was 3D bioprintable and perfusable.

Serum Nardilysin as a Prognostic Biomarker in Pancreatic Ductal Adenocarcinoma

Background: Nardilysin, (N-arginine dibasic convertase, NRDC) has been reported to play an important role in cancer progression, and is associated with tumor proliferation signals and inflammatory signals, such as tumor necrosis factor-a (TNF-a) and heparin-binding epidermal growth factor-like growth factor (HB-EGF), through the activation of disintegrin and metalloproteinase (ADAM) proteases. NRDC has recently been revealed to be involved in the tumorigenesis of various types of cancer, including intrahepatic cholangiocarcinoma, malignant cerebral infarction, esophageal squamous cell carcinoma, and gastric cancer. However, the expression profiles and biological relevance of NRDC in pancreatic ductal adenocarcinoma have rarely been reported. Methods: We analyzed the NRDC expression profile in pancreatic ductal adenocarcinoma by enzyme-linked immunosorbent assay (ELISA) and identified NRDC as a circulating biomarker in the serum of 112 pancreatic ductal adenocarcinoma patients. The diagnostic value of NRDC was analyzed by the area under the curve (AUC) and the receiver operating characteristic (ROC) test. Results: Our results demonstrated that the clinical prognosis significance of NRDC with the clinical characteristics in pancreatic ductal adenocarcinoma (PDAC). NRDC was notably decreased in PDAC patient serum compared with the control group (p < 0.001). Furthermore, the present study found that the NRDC expression level was correlated with T grade (p < 0.001), metastasis(p < 0.001), differentiation(p < 0.001), and TNM stage (p = 0.011). Further bioinformatics analysis revealed that NRDC correlated with proliferation and migration pathways; in particular, it mediated cell-matrix adhesion-dependent activation in pancreatic ductal adenocarcinoma. Conclusions: Serum NRDC may play a useful diagnostic biomarker to evaluate the aggressive clinical features in PAAD patients.

Role of the Transcription Factor MAFA in the Maintenance of Pancreatic β-Cells

Pancreatic β-cells are specialized to properly regulate blood glucose. Maintenance of the mature β-cell phenotype is critical for glucose metabolism, and β-cell failure results in diabetes mellitus. Recent studies provide strong evidence that the mature phenotype of β-cells is maintained by several transcription factors. These factors are also required for β-cell differentiation from endocrine precursors or maturation from immature β-cells during pancreatic development. Because the reduction or loss of these factors leads to β-cell failure and diabetes, inducing the upregulation or inhibiting downregulation of these transcription factors would be beneficial for studies in both diabetes and stem cell biology. Here, we discuss one such factor, i.e., the transcription factor MAFA. MAFA is a basic leucine zipper family transcription factor that can activate the expression of insulin in β-cells with PDX1 and NEUROD1. MAFA is indeed indispensable for the maintenance of not only insulin expression but also function of adult β-cells. With loss of MAFA in type 2 diabetes, β-cells cannot maintain their mature phenotype and are dedifferentiated. In this review, we first briefly summarize the functional roles of MAFA in β-cells and then mainly focus on the molecular mechanism of cell fate conversion regulated by MAFA.

Nardilysin in adipocytes regulates UCP1 expression and body temperature homeostasis

Brown adipose tissue (BAT) dissipates chemical energy as heat through uncoupling protein 1 (UCP1). The induction of mitochondrial reactive oxygen species (ROS) in BAT was recently identified as a mechanism that supports UCP1-dependent thermogenesis. We previously demonstrated that nardilysin (NRDC) plays critical roles in body temperature homeostasis. Global NRDC-deficient (Nrdc^–/–) mice show hypothermia due to a lower set point for body temperature, whereas BAT thermogenesis at room temperature (RT) is enhanced mainly to compensate for poor thermal insulation. To examine the primary role of NRDC in BAT thermogenesis, we generated adipocyte-specific NRDC-deficient (Adipo-KO) mice by mating Nrdc floxed (Nrdc^flox/flox) mice with adiponectin-Cre mice. Adipo-KO mice showed hyperthermia at both RT and thermoneutrality. They were also more cold-tolerant than Nrdc^flox/flox mice. However, UCP1 mRNA levels were significantly lower in Adipo-KO BAT at RT, thermoneutrality, and 4 °C, whereas no significant differences were observed in UCP1 protein levels at RT and 4 °C. We examined the protein stability of UCP1 using the cycloheximide chase assay and found that NRDC negatively regulated its stability via the ubiquitin–proteasome pathway. NRDC may be also involved in ROS-mediated in vivo thermogenesis because the inhibitory effects of N-acetyl cysteine, an ROS scavenger, on β3 agonist-induced thermogenesis were stronger in Adipo-KO mice. Collectively, the present results demonstrate that NRDC in BAT controls adaptive thermogenesis and body temperature homeostasis possibly via the regulation of UCP1 protein stability and ROS levels.

Deficiency of Nardilysin in the Liver Reduces Serum Cholesterol Levels

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.

Modulation of Insulin Sensitivity by Insulin-Degrading Enzyme

Insulin-degrading enzyme (IDE) is a highly conserved and ubiquitously expressed metalloprotease that degrades insulin and several other intermediate-size peptides. For many decades, IDE had been assumed to be involved primarily in hepatic insulin clearance, a key process that regulates availability of circulating insulin levels for peripheral tissues. Emerging evidence, however, suggests that IDE has several other important physiological functions relevant to glucose and insulin homeostasis, including the regulation of insulin secretion from pancreatic β-cells. Investigation of mice with tissue-specific genetic deletion of Ide in the liver and pancreatic β-cells (L-IDE-KO and B-IDE-KO mice, respectively) has revealed additional roles for IDE in the regulation of hepatic insulin action and sensitivity. In this review, we discuss current knowledge about IDE’s function as a regulator of insulin secretion and hepatic insulin sensitivity, both evaluating the classical view of IDE as an insulin protease and also exploring evidence for several non-proteolytic functions. Insulin proteostasis and insulin sensitivity have both been highlighted as targets controlling blood sugar levels in type 2 diabetes, so a clearer understanding the physiological functions of IDE in pancreas and liver could led to the development of novel therapeutics for the treatment of this disease.

Nardilysin controls cardiac sympathetic innervation patterning through regulation of p75 neurotrophin receptor

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 (p75^NTR , Ngfr) is increased in Nrdc^-/- LV due to the reduced ectodomain shedding of p75^NTR . Importantly, the reduction of p75^NTR 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 p75^NTR .

Nardilysin inhibits pancreatitis and suppresses pancreatic ductal adenocarcinoma initiation in mice

OBJECTIVE

Nardilysin (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).

DESIGN

We analysed Ptf1a-Cre; Nrdc^flox/flox mice to investigate the impact of Nrdc deletion. Pancreatic acinar cells were isolated from Nrdc^flox/flox mice and infected with adenovirus expressing Cre recombinase to examine the impact of Nrdc inactivation. Global gene expression in Nrdc-cKO pancreas was analysed compared with wild-type pancreas by microarray analysis. We also analysed Ptf1a-Cre; Kras^G12D; Nrdc^flox/flox mice to investigate the impact of Nrdc deletion 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.

RESULTS

We found that pancreatic deletion of Nrdc leads 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 in Nrdc-null pancreatic acinar cells. Furthermore, pancreatic deletion of Nrdc dramatically accelerated Kras^G12D -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.

CONCLUSION

Nrdc inhibits pancreatitis and suppresses PDA initiation in mice.

Clinical determination of serum nardilysin levels in predicting 30-day mortality among adults with malignant cerebral infarction

BACKGROUND

Nardilysin, a kind of metalloendopeptidase, plays an important role in numerous inflammatory diseases. Malignant cerebral infarction (Glasgow coma scale score of <9) is associated with a high mortality risk. Here, we intended to investigate the relationship between serum nardilysin levels and prognosis of patients with malignant cerebral infarction.

METHODS

Serum nardilysin concentrations were quantified at malignant cerebral infarction diagnosis moment in 105 patients and at study entrance in 105 healthy controls. Association of nardilysin concentrations with 30-day mortality and overall survival was estimated using multivariate analyses.

RESULTS

The patients exhibited substantially increased serum nardilysin concentrations, as compared to the controls. Nardilysin concentrations were in pronounced correlation with Glasgow coma scale scores and serum C-reactive protein concentrations. Serum nardilysin was independently predictive of 30-day mortality and overall survival. Under receiver operating characteristic curve, its high discriminatory ability was found.

CONCLUSIONS

Rising serum nardilysin concentrations following malignant cerebral infarction are strongly related to stroke severity, inflammatory extent and a higher risk of mortality, substantializing serum nardilysin as a potential prognostic biomarker for malignant cerebral infarction.

Serum Nardilysin, a Surrogate Marker for Epithelial-Mesenchymal Transition, Predicts Prognosis of Intrahepatic Cholangiocarcinoma after Surgical Resection

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.

Nardilysin controls intestinal tumorigenesis through HDAC1/p53-dependent transcriptional regulation

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.

Nardilysin is a promising biomarker for the early diagnosis of acute coronary syndrome

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<0.0001). The area under the curve of NRDC for the diagnosis of ACS was 0.822 by the receiver operating characteristic curves analysis. In the time course analysis in 43 consecutive ACS patients (AMI: 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 H₂O₂ 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.

Genome-wide profiling of nardilysin target genes reveals its role in epigenetic regulation and cell cycle progression

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.

Nardilysin is involved in autoimmune arthritis via the regulation of tumour necrosis factor alpha secretion

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 (Nrdc^delM) 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 Nrdc^delM 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.

Nardilysin promotes hepatocellular carcinoma through activation of signal transducer and activator of transcription 3

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.