BACKGROUNDMesenchymal stem cells are a promising cell type for cell transplantation in myocardial infarction. Type I neuregulins-1, also known as heregulin, can promote the survival of cardiomyocytes and stimulate angiogenesis. The purpose of this study was to investigate the expression of heregulin and ErbB receptors in mesenchymal stem cells, then further detect the secretion of heregulin and the changes in expression of heregulin and ErbB receptors under conditions of serum deprivation and hypoxia.

METHODSMesenchymal stem cells isolated from bone marrow of 180 g male Sprague-Dawley rats were cultured. Passage 3 cells were detected experimentally by regular reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative real time PCR and Western blotting.

RESULTSHeregulin and ErbB receptors were expressed in mesenchymal stem cells, and all three ErbB receptors mRNA expressions were significantly down-regulated by serum deprivation and hypoxia, but serum deprivation and hypoxia significantly increased the protein expression of heregulin. Serum deprivation and hypoxia more than 12 hours could induce the secretion of heregulin.

CONCLUSIONSMesenchymal stem cells can express all three ErbB receptors and heregulin. Serum deprivation and hypoxia decrease the mRNA expression of ErbB receptors, increase the expression of heregulin, and activate the secretion of heregulin.

Animals ; Cell Hypoxia ; Cells, Cultured ; Male ; Mesenchymal Stromal Cells ; chemistry ; metabolism ; Neuregulin-1 ; analysis ; genetics ; Oncogene Proteins v-erbB ; analysis ; genetics ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the role of neuregulin (neural regulation of protein, NRG) in the process of mouse spermatogonia proliferation.

METHODSMouse testis fragments were cultured in the medium DMEM containing purified NRG1beta or NRG3 at the concentration of 50, 100 and 200 ng/ml, respectively, followed by BrdU immunohistochemical staining and determination of the proliferation rate of spermatogonia.

RESULTSCompared with the control group, neuregulin significantly promoted the proliferation of spermatogonia (P < 0.05). The proliferation rates of spermatogonia cultured in the medium with 50, 100 and 200 ng/ml of NRG13 were 1.69, 1.55 and 1.86 times, and those with 50, 100 and 200 ng/ml of NRG3 were 1.35, 1.54 and 2.11 times that of the control.

CONCLUSIONNRG1beta and NRG3 can promote the proliferation of mouse spermatogonia, and NRG is expected to be applied in the treatment of male infertility.

Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Intracellular Signaling Peptides and Proteins ; pharmacology ; Male ; Mice ; Mice, Inbred C57BL ; Neuregulin-1 ; pharmacology ; Signal Transduction ; Spermatogonia ; cytology ; metabolism

OBJECTIVETo study the changes in endogenous neuregulin-1 (Nrg1) expression in the anterior pituitary of female Wistar-Furth rats in different phases of the estrous cycle.

METHODSFemale Wistar-Furth rats during estrous cycles were used. RT-PCR was employed to study the changes in the expression of Nrg1 isoforms and their cognate receptors ErbB-2 and ErbB-4 in the anterior pituitary in different phases of the estrous cycle. Western blotting was used to detect Nrg1 expression at the protein level. Immunofluorescence staining was used to identify hypophyseal cells expressing Nrg1 and observe the localization and distribution of Nrg1 and functional phosphorylation of ErbB-4. The co-expression of Nrg1 and ErbB-4 in the anterior pituitary of Rhesus monkey was also investigated.

RESULTSSome of the Nrg1 isoforms, especially type III Nrg1s, were expressed at a higher level during the estrous cycle I (E1) and estrous cycle II (E2), a result consistent with that of Western blotting for samples of the anterior pituitaries collected at these phases. Immunofluorescence staining identified the gonadotrophs as the main source of Nrg1, and showed an extensive distribution of Nrg1 in the anterior pituitary in E1 and E2 phases accompanied by apparent phosphorylated activation of ErbB-4. Adjacent distribution of Nrg1- and ErbB-4-positive cells was also observed in the anterior pituitary of male Rhesus monkeys.

CONCLUSIONOur results provide evidence for the expression of multiple Nrg1 isoforms and the presence of Nrg1/ErbB-4 signaling in the anterior pituitary of female Wistar-Furth rats. This signaling demonstrates an estrous cycle phase-related pattern. Additionally, Nrg1/ErbB-4-based juxtacrine signaling may exist in the anterior pituitary of male non-human primate.

Animals ; Estrous Cycle ; physiology ; Female ; Macaca mulatta ; Male ; Neuregulin-1 ; metabolism ; Phosphorylation ; Pituitary Gland ; metabolism ; Protein Isoforms ; metabolism ; Rats ; Rats, Inbred WF ; Receptor, Epidermal Growth Factor ; metabolism ; Receptor, ErbB-4

BACKGROUNDMitochondrial dysfunction plays a pivotal role in the progression of left ventricular (LV) remodeling and heart failure (HF). Recombinant human neuregulin-1 (rhNRG-1) improves cardiac function in models of experimental HF and in clinical trials; however, its impact on mitochondrial function during chronic HF remains largely unknown. The purpose of this study was to investigate whether rhNRG-1 could attenuate the functional and structural changes that occur in cardiac mitochondria in a rat model of HF induced by myocardial infarction.

METHODSSixty adult rats underwent sham or coronary ligation to induce HF. Four weeks after ligation, 29 animals with LV ejective fraction ≤ 50% were randomized to receive either vehicle or rhNRG-1 (10 µg×kg(-1)×d(-1), I.V.) for 10 days, another 12 sham-operated animals were given no treatment. Echocardiography was used to determine physiological changes. Mitochondrial membrane potential (MMP), respiratory function and tissue adenosine triphosphate (ATP) production were analyzed. Cytochrome c expression and cardiomyocyte apoptosis were determined. Oxidative stress was evaluated by reactive oxygen species production using fluorescence assays and gene expression of glutathione peroxidase measured by real-time quantitative PCR.

RESULTSCompared with sham-operated animals, vehicle treated HF rats exhibited severe LV remodeling and dysfunction, significant mitochondrial dysfunction, increased mitochondrial cytochrome c release, increased myocyte apoptosis and enhanced oxidative stress. Short-term treatment with rhNRG-1 significantly attenuated LV remodeling and cardiac function. Concomitant with this change, mitochondrial dysfunction was significantly attenuated; with ATP production, MMP and respiratory function restored, cytochrome c release and apoptosis inhibited, and oxidative stress reduced.

CONCLUSIONThe present study demonstrated that rhNRG-1 can significantly improve LV remodeling and cardiac function in the failing heart, this beneficial effect is related to reducing mitochondrial dysfunction, myocyte apoptosis and oxidative stress.

Animals ; Apoptosis ; drug effects ; Blotting, Western ; Echocardiography ; Heart Failure ; Mitochondria ; drug effects ; metabolism ; Myocardial Infarction ; drug therapy ; metabolism ; pathology ; Neuregulin-1 ; therapeutic use ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Real-Time Polymerase Chain Reaction

OBJECTIVETo explore the effect of anti-psychotic treatment on the expression of Neuregulin-1 (NRG1) mRNA in the peripheral blood lymphocytes of schizophrenia patients.

METHODSThe NRG1 mRNA in peripheral blood lymphocytes was measured using semi-quantitative reverse transcription (RT)-PCR in 80 first-onset schizophrenia patients, 37 sibling controls and 83 non-related controls. The patients were treated with risperdone and quetiapine for 4 weeks. Positive and negative symptom scale (PANSS) was used to evaluate the severity and clinical efficacy.

RESULTSPrior to the treatment, the expression of NRG1 mRNA expression was significantly lower in patients than other two groups (F=73.004, P=0.000). From the second week on, the level of NRG1 mRNA expression in patients became significantly higher than before and gradually increased, whilst no significant difference between sib and non-sib controls. Prior to the treatment, there was significant correlation (r=-0.232, P=0.038) between the level of NRG1 mRNA and PANSS scores. Four weeks after the treatment, a significant correlation between the reduction rate of PANSS and the change of NRG1 mRNA (r=0.27, P=0.016).

CONCLUSIONThe expression of NRG1 gene mRNA is associated with schizophrenia. Decreased expression of NRG1 may play a role in the development of schizophrenia, which can be improved by anti-psychotic drugs.

Adolescent ; Adult ; Antipsychotic Agents ; pharmacology ; therapeutic use ; Female ; Gene Expression ; drug effects ; Gene Expression Regulation ; drug effects ; Humans ; Male ; Neuregulin-1 ; genetics ; RNA, Messenger ; metabolism ; Schizophrenia ; drug therapy ; genetics ; Time Factors ; Young Adult

OBJECTIVE: To explore the correlation between signs similar to schizophrenia in mice after ketamine administration and the expressions of NRG1 and ErbB4 mRNA in order to explain the possible pathogenesis of schizophrenia. METHODS: Fifty KM mice were randomly divided into 5 groups which were administered intraperitoneally with saline, clozapine and different dosages ketamine. The ketamine groups were administered intraperitoneally with low dosage (25 mg/kg), middle dosage (50 mg/kg) and high dosage (100 mg/kg) one time every day for 7 days. After administration of 100 mg/kg ketamine for 7 days, the clozapine group was introgastrically administered 20 mg/kg with clozapine one time every day for 7 days. The pathological changes of hippocampus neurons were observed by HE stain. The expressions of the NRG1 and ErbB4 mRNA in hippocampus were detected by reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: In the group with high dosage of ketamine, the levels of NRG1 and ErbB4 mRNA were significantly lower than that of the group with saline. CONCLUSION Ketamine may induce signs similar to schizophrenia in KM mice. The mechanism may be involved in the reduction of NRG1 and ErbB4 mRNA expression.
Animals ; Clozapine/therapeutic use* ; Disease Models, Animal ; Dose-Response Relationship, Drug ; ErbB Receptors/metabolism* ; Hippocampus/pathology* ; Ketamine/adverse effects* ; Male ; Mice ; Neuregulin-1/metabolism* ; Neurons/metabolism* ; RNA, Messenger/metabolism* ; Random Allocation ; Receptor, ErbB-4 ; Reverse Transcriptase Polymerase Chain Reaction ; Schizophrenia/genetics*

Overexpression of HER2 correlates with more aggressive tumors and increased resistance to cancer chemotherapy. However, a functional comparison between the HER2high/HER3 and the HER2low/HER3 dimers on tumor metastasis has not been conducted. Herein we examined the regulation mechanism of heregulin-beta1 (HRG)-induced MMP-1 and -9 expression in breast cancer cell lines. Our results showed that the basal levels of MMP-1 and -9 mRNA and protein expression were increased by HRG treatment. In addition, HRG-induced MMP-1 and -9 expression was significantly decreased by MEK1/2 inhibitor, U0126 but not by phosphatidylinositol 3-kinase (PI-3K) inhibitor, LY294002. To confirm the role of MEK/ERK pathway on HRG-induced MMP-1 and -9 expression, MCF7 cells were transfected with constitutively active adenoviral-MEK (CA-MEK). The level of MMP-1 and -9 expressions was increased by CA-MEK. MMP-1 and -9 mRNA and protein expressions in response to HRG were higher in HER2 overexpressed cells than in vector alone. The phosphorylation of HER2, HER3, ERK, Akt, and JNK were also significantly increased in HER2 overexpressed MCF7 cells compared with vector alone. HRG-induced MMP-1 and -9 expressions were significantly decreased by lapatinib, which inhibits HER1 and HER2 activity, in both vector alone and HER2 overexpressed MCF7 cells. Finally, HRG-induced MMP-1 and MMP-9 expression was decreased by HER3 siRNA overexpression. Taken together, we suggested that HRG-induced MMP-1 and MMP-9 expression is mediated through HER3 dependent pathway and highly expressed HER2 may be associated with more aggressive metastasis than the low expressed HER2 in breast cancer cells.
Breast Neoplasms/enzymology/*genetics/*metabolism ; Butadienes/pharmacology ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Enzyme Inhibitors/pharmacology ; Female ; Gene Expression ; Gene Expression Regulation, Neoplastic/drug effects ; Humans ; MAP Kinase Signaling System ; MCF-7 Cells ; Matrix Metalloproteinase 1/*genetics/metabolism ; Matrix Metalloproteinase 9/*genetics/metabolism ; Neuregulin-1/*pharmacology ; Nitriles/pharmacology ; Phosphatidylinositol 3-Kinases/metabolism ; Protein Kinase Inhibitors/pharmacology ; Protein Multimerization ; Proto-Oncogene Proteins c-akt/metabolism ; Quinazolines/pharmacology ; Receptor, erbB-2/genetics/*metabolism ; Receptor, erbB-3/*metabolism

BACKGROUNDNeuregulin-1 (NRG-1), the ligand of the myocardial ErbB receptor, is a protein mediator with regulatory actions in the heart. This study investigated whether NRG-1 preconditioning has protective effects on myocardial ischemia/reperfusion (I/R) injury and its potential mechanism.

METHODSWe worked with an in vivo rat model with induced myocardial ischemia (45 minutes) followed by reperfusion (3 hours). NRG-1 message was detected in the heart using RT-PCR and the protein levels of NRG-1 and ErbB4 were detected by Western blotting analysis. Infarct size was assessed using the staining agent triphenyltetrazolium chloride and cardiac function was continuously monitored. The levels of creatine kinase and lactate dehydrogenase in plasma were analyzed to assess the degree of cardiac injury. The extent of cardiac apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and by Western blotting analysis of cleaved caspase-3. We examined the phosphorylation of Akt in the myocardium and the effect of PI3K/Akt inhibition on NRG-1-induced cardioprotection.

RESULTSTranscription and expression of NRG-1 and phosphorylation of its ErbB4 receptor were significantly upregulated in the I/R hearts. NRG-1 pretreatment reduced the infarct size following cardiac I/R in a concentration-dependent manner with an optimal concentration of 4 µg/kg in vivo. NRG-1 pretreatment with 4 µg/kg, i.v. markedly reduced the plasma creatine kinase and lactate dehydrogenase levels. Pretreatment with NRG-1 also significantly reduced the percentage of TUNEL positive myocytes and the level of cleaved caspase-3 in the I/R hearts. Pretreatment with NRG-1 significantly increased phosphorylation of Akt following I/R. Furthermore, the cardioprotective effect limiting the infarct size that was induced by NRG-1 was abolished by co-administration of the PI3K inhibitor LY294002.

CONCLUSIONSThe concentration of NRG-1, a new autacoid, was rapidly upregulated after myocardial I/R. NRG-1 preconditioning has cardioprotective effects against I/R injury through a PI3K/Akt-dependent mechanism in vivo.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Dose-Response Relationship, Drug ; Ischemic Preconditioning, Myocardial ; L-Lactate Dehydrogenase ; blood ; Male ; Myocardial Reperfusion Injury ; prevention & control ; Neuregulin-1 ; analysis ; pharmacology ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; physiology ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; physiology ; Rats ; Rats, Sprague-Dawley ; Receptor, Epidermal Growth Factor ; analysis ; Receptor, ErbB-4