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 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

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