Persistent NRG1 Type III Overexpression in Spinal Motor Neurons Has No Therapeutic Effect on ALS-Related Pathology in SOD1G93A Mice.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease affecting upper and lower motor neurons (MNs). Neuregulin-1 (NRG1) is a pleiotropic growth factor that has been shown to be potentially valuable for ALS when supplemented by means of viral-mediated gene therapy. However, these results are inconsistent with other reports. An alternative approach for investigating the therapeutic impact of NRG1 on ALS is the use of transgenic mouse lines with genetically defined NRG1 overexpression. Here, we took advantage of a mouse line with NRG1 type III overexpression in spinal cord α motor neurons (MN) to determine the impact of steadily enhanced NRG1 signalling on mutant superoxide dismutase 1 (SOD1)-induced disease. The phenotype of SOD1G93A-NRG1 double transgenic mice was analysed in detail, including neuropathology and extensive behavioural testing. At least 3 animals per condition and sex were histopathologically assessed, and a minimum of 10 mice per condition and sex were clinically evaluated. The accumulation of misfolded SOD1 (mfSOD1), MN degeneration, and a glia-mediated neuroinflammatory response are pathological hallmarks of ALS progression in SOD1G93A mice. None of these aspects was significantly improved when examined in double transgenic NRG1-SOD1G93A mice. In addition, behavioural testing revealed that NRG1 type III overexpression did not affect the survival of SOD1G93A mice but accelerated disease onset and worsened the motor phenotype.

Jatrorrhizine ameliorates Schwann cell myelination via inhibiting HDAC3 ability to recruit Atxn2l for regulating the NRG1-ErbB2-PI3K-AKT pathway in diabetic peripheral neuropathy mice.

Diabetic peripheral neuropathy (DPN) is a chronic complication associated with nerve dysfunction and uncontrolled hyperglycemia. Unfortunately, due to its complicated etiology, there has been no successful therapy for DPN. Our research recently revealed that jatrorrhizine (JAT), one of the active constituents of Rhizoma Coptidis, remarkably ameliorated DPN. This work highlighted the potential mechanism through which JAT relieves DPN using db/db mice. The results indicated that JAT treatment significantly decreased the threshold for thermal and mechanical stimuli and increased nerve conduction velocity. Histopathological analysis revealed that JAT significantly increased the number of sciatic nerve fibers and axons, myelin thickness, and axonal diameters. Additionally, JAT markedly elevated the expression of myelination-associated proteins (MBP, MPZ, and Pmp22). The screening of histone deacetylases (HDAC) determined that histone deacetylase 3 (HDAC3) is an excellent target for JAT-induced myelination enhancement. Liquid chromatography-mass spectrometry-(MS)/MS and coimmunoprecipitation analyses further confirmed that HDAC3 antagonizes the NRG1-ErbB2-PI3K-AKT signaling axis by interacting with Atxn2l to augment SCs myelination. Thus, JAT ameliorates SCs myelination in DPN mice via inhibiting the recruitment of Atxn2l by HDAC3 to regulate the NRG1-ErbB2-PI3K-AKT pathway.

Epimedium flavonoids improve cognitive impairment and white matter lesions induced by chronic cerebral hypoperfusion through inhibiting the Lingo-1/Fyn/ROCK pathway and activating the BDNF/NRG1/PI3K pathway in rats.

Chronic cerebral hypoperfusion is a common cause of cerebral small vascular disease (CSVD). White matter (WM) lesions are the typical pathological manifestation of CSVD and contribute to cognitive decline. Epimedium flavonoids (EF) are the main component in Epimedium brevicornu Maxim., which is commonly used in traditional Chinese medicine. The purpose of this study was to investigate the effects of EF on cognitive impairment and the underlying mechanisms in a CSVD rat model induced with chronic cerebral hypoperfusion. The model was established by permanent bilateral common carotid artery occlusion (2VO) in rats. EF (50, 100, and 200 mg/kg) was intragastrically administered once a day for 12 weeks starting 2 weeks after 2VO surgery. The learning and memory capacity of the rats were measured using the Morris water maze and step-through tests. WM lesions were observed by MRI-diffusion tensor imaging, transmission electron microscopy, and LFB staining. Oligodendrocytes were detected by immunohistochemistry. Western blotting assay was used to determine the level of protein expression. The results showed that EF significantly improved learning and memory impairment, alleviated WM nerve fiber injuries and demyelination, and increased the number of mature oligodendrocytes in the corpus callosum, subcortical WM, and periventricular WM in 2VO rats. Mechanistically, EF reduced the expression of Lingo-1 and ROCK2 and increased the levels of phosphorylated (p-) Fyn, brain-derived neurotrophic factor (BDNF), TrkB, neuregulin-1 (NRG-1), p-ErbB4, PI3K p85 and p110α, p-Akt, and p-CREB in the corpus callosum of 2VO rats. These results suggest that EF may improve cognitive impairment and WM lesions induced by chronic cerebral hypoperfusion through inhibiting the Lingo-1/Fyn/ROCK pathway and activating the BDNF/TrkB, NRG-1/ErbB4, and the downstream PI3K/Akt/CREB pathways in WM. Thus, EF can be used as a potential neuroprotective agent in CSVD therapy.

[Effects of electroacupuncture on sympathetic nerve-related substance in myocardial tissue in mice with myocardial ischemia].

OBJECTIVE: To observe the effects of electroacupuncture (EA) on sympathetic nerve-related substance in myocardial tissue in mice with myocardial ischemia (MI), and to explore its possible mechanism. METHODS: Thirty adult male C57BL/6 mice were randomly divided into a sham operation group, a model group and an EA group, 10 mice in each one. The model of MI was established in the model group and EA group by ligating the left anterior descending branch of coronary artery. The mice in the sham operation group were not treated with ligating at left anterior descending branch of coronary artery, but the remaining procedure was similar with the model group. The mice in the EA group were treated with EA at "Neiguan" (PC 6) with 2 Hz/100 Hz of frequency and 2 mA of intensity, 20 min per treatment, once a day for totally 5 days. No EA was given for model group and sham operation group. The electrocardiogram was recorded and △ST value was calculated to evaluate the model. TTC staining was applied to evaluate the infarct size. Immunohistochemical (IHC) method was applied to evaluate the positive nerve fiber density in myocardial tissue. Western blot method was applied to test the protein expression levels of neuregulin-1 (NRG-1), tyrosine hydroxylase (TH), growth associated protein-43 (GAP-43). RESULTS: The electrocardiogram (lead II) results indicated compared with the sham operation group, the S-T segments in the model group and EA group were increased obviously (both P<0.01), indicating the MI model was established successfully. The TTC staining results indicated compared with sham operation group, the infarction size was significantly increased in the model group (P<0.01); compared with the model group, the infarction size in the EA group was significantly reduced (P<0.01). The IHC results indicated compared with the sham operation group, the positive nerve fiber density in myocardial was increased in the model group (P<0.01); compared with the model group, the positive nerve fiber density in myocardial was reduced in the EA group (P<0.05). The Western blot results indicated compared with the sham operation group, the expression levels of TH, NRG-1 and GAP-43 were significantly increased in the model group (P<0.01); compared with the model group, the expression level of TH and GAP-43 were significantly reduced (P<0.01) and that of NRG-1 was increased in the EA group (P<0.05). CONCLUSION: EA could increase the expression of NRG-1 and reduce the expression of TH and GAP-43 in myocardial tissues in MI mice, which could suppress sympathetic nerve hyperexcitability after infarction to achieve myocardial protection effect.

Effects of electroacupuncture on sympathetic nerve-related substance in myocardial tissue in mice with myocardial ischemia / 中国针灸

OBJECTIVE@#To observe the effects of electroacupuncture (EA) on sympathetic nerve-related substance in myocardial tissue in mice with myocardial ischemia (MI), and to explore its possible mechanism.@*METHODS@#Thirty adult male C57BL/6 mice were randomly divided into a sham operation group, a model group and an EA group, 10 mice in each one. The model of MI was established in the model group and EA group by ligating the left anterior descending branch of coronary artery. The mice in the sham operation group were not treated with ligating at left anterior descending branch of coronary artery, but the remaining procedure was similar with the model group. The mice in the EA group were treated with EA at "Neiguan" (PC 6) with 2 Hz/100 Hz of frequency and 2 mA of intensity, 20 min per treatment, once a day for totally 5 days. No EA was given for model group and sham operation group. The electrocardiogram was recorded and △ST value was calculated to evaluate the model. TTC staining was applied to evaluate the infarct size. Immunohistochemical (IHC) method was applied to evaluate the positive nerve fiber density in myocardial tissue. Western blot method was applied to test the protein expression levels of neuregulin-1 (NRG-1), tyrosine hydroxylase (TH), growth associated protein-43 (GAP-43).@*RESULTS@#The electrocardiogram (lead II) results indicated compared with the sham operation group, the S-T segments in the model group and EA group were increased obviously (both <0.01), indicating the MI model was established successfully. The TTC staining results indicated compared with sham operation group, the infarction size was significantly increased in the model group (<0.01); compared with the model group, the infarction size in the EA group was significantly reduced (<0.01). The IHC results indicated compared with the sham operation group, the positive nerve fiber density in myocardial was increased in the model group (<0.01); compared with the model group, the positive nerve fiber density in myocardial was reduced in the EA group (<0.05). The Western blot results indicated compared with the sham operation group, the expression levels of TH, NRG-1 and GAP-43 were significantly increased in the model group (<0.01); compared with the model group, the expression level of TH and GAP-43 were significantly reduced (<0.01) and that of NRG-1 was increased in the EA group (<0.05).@*CONCLUSION@#EA could increase the expression of NRG-1 and reduce the expression of TH and GAP-43 in myocardial tissues in MI mice, which could suppress sympathetic nerve hyperexcitability after infarction to achieve myocardial protection effect.

Astraglaus polysaccharide protects diabetic cardiomyopathy by activating NRG1/ErbB pathway.

Diabetic cardiomyopathy (DCM) is one of the main cardiac complications among diabetic patients. According to previous studies, the pathogenesis of DCM is associated with oxidative stress, apoptosis and proliferation of local cardiac cells. It showed, NRG1 can improve the function of mitochondria, and thereby, increasing proliferation and decreasing apoptosis of cardiac muscle cell via ErbB/AKT signaling, also, exert antioxidative function. Besides, NRG1/ErbB pathway was impaired in the DCM model which suggested this signaling played key role in DCM. Astraglaus polysaccharide (APS), one of the active components of Astragalus mongholicus, showed striking antioxidative effect. Here, in this study, our data showed that APS can promote proliferation and decrease apoptosis in AGE-induced DCM cell model, besides, APS can decrease intracellular ROS level, increase activity of SOD, GSH-Px and lower level of MDA and NO in DCM cell model, indicating APS exerted antioxidative function in DCM model cells. Besides, western blot results revealed APS induced NRG1 expressing and the phosphorylation level of ErbB2/4. In addition, the elevated NRG1 promoted AKT and PI3k phosphorylation which indicated APS may exert its function by NRG1/ErbB and the downstream AKT/PI3K signaling. Canertinib is ErbB inhibitor. The effect of APS on proliferation, apoptosis, antioxidation and NRG1/ErbB pathway was partly abolished after the cells were co-treated with APS and canertinib. Taken together, these results suggested APS may display its protective function in DCM cells by activating NGR1/ErbB signaling pathway. And our study increased potential for prevention and therapy to DCM.

Electroacupuncture at Quchi and Zusanli points reduces cell apoptosis by activating Nrg-1 and ErbB4 signaling pathways in cerebral ischemia-reperfusion rats / 医学研究生学报

Objective The mechanism of electroacupuncture (EA) in the treatment of neurological dysfunction caused by ischemic stroke remains to be further explored. This study aimed to investigate the effects of EA at the Quchi (LI11) and Zusanli (ST36) points on the expressions of Nrg-1 and ErbB4 proteins and their correlation with the expressions of cell apoptosis-related proteins bcl-2 and Bax in cerebral ischemia-reperfusion (I-R) rats.Methods Totally 160 male adult SD rats were randomly assigned to four groups of equal number: sham operation, middle cerebral artery occlusion-reperfusion (MCAO-R) model, acupoint, and non-acupoint. After MCAO/R modeling, EA was applied at Quchi and Zusanli in the acupoint group and at ipsilateral non-acupoints below the axillary striation and apex of the coccyx in the non-acupoint group. At 3 days after treatment, the protein and mRNA expressions of Bcl-2, Bax, Nrg-1 and ErbB4 were determined by TTC, TUNEL, immunohistochemistry, Western blot, and RT-PCR.Results The neurological deficit score was significantly increased after cerebral I/R injury in the MCAO-R model, acupoint and non-acupoint groups compared with that in the sham operation group (P<0.01). EA therapy markedly reduced the neurological deficit scores (P<0.05), cerebral infarct area (P<0.05) and the number of apoptotic cells (P<0.05), up-regulated the protein expressions of Nrg-1, ErbB4 and Bcl-2 (P<0.05), and down-regulated that of Bax (P<0.05). There was a pronounced increase in the protein and mRNA expressions of Nrg-1 and ErbB4 in the acupoint group compared with the MCAO-R model and non-acupoint groups after cerebral I-R injury (P<0.01).Conclusion EA at the Quchi and Zusanli points has a neuroprotective effect in ischemic brain injury by up-regulating the expressions of endogenous Nrg-1 and its receptor ErbB4 and down-regulating those of Bcl-2 and Bax. The underlying mechanism is probably associated with the Nrg-1/ErbB4 signaling pathway.

Discovery of ERBB3 inhibitors for non-small cell lung cancer (NSCLC) via virtual screening.

As a member of the epidermal growth factor receptor family (EGFR) of receptor tyrosine kinases, ERBB3 plays an important role in mediating cellular growth and differentiation. Recent research works identified that CD74-NRG1 fusions lead to overexpression of the EGF-like domain of NRG1, and thus activate ERBB3 and PI3K-AKT signaling pathways. The fusion was detected in lung adenocarcinomas, and served as an important oncogenic factor for ERBB3 driven cancers. A sequential virtual screening strategy has been applied to ERBB3 crystal structure using databases of natural products and Chinese traditional medicine compounds, and led to identification of a group of small molecular compounds potentially capable of blocking ERBB3. Six small molecular compounds were selected for in vitro analysis. Five of these molecules significantly inhibited the growth of A549 cells. Among them, compound VS1 is the most promising one with IC50 values of 269.75 µM, comparing to the positive control of nimustine hydrochloride with IC50 values of 264.14 µM. With good specificity and predicted ADMET results, our results support the feasibility by using a pharmacophore of the compound VS1 for designing and optimization of ERBB3 inhibitors.

Molecular cloning and expression analysis of neuregulin 1 (Nrg1) in the hypothalamus of Huoyan goose during different stages of the egg-laying cycle.

Neuregulin 1 (Nrg1) is one of the most active members of the epidermal growth factor (EGF)-like family, which bind to the ErbB tyrosine kinase receptor and play many roles in modulation of synaptic activity, synaptogenesis, GABAergic neurotransmission, neurotransmitter receptor expression and the hormonal control of neuroendocrine reproductive development. In this study, we cloned and characterized the cDNA of goose Nrg1 originating from hypothalamus tissues of Huoyan goose using RACE method, investigated the mRNA expression profiles during different stages of the egg-laying cycle by real-time PCR. Multiple alignments and phylogenetic analyses of the deduced amino acid sequence were conducted using bioinformatics tools. We also determined the profiles of blood serum progesterone, estradiol, FSH and LH content during different egg-laying stages using radioimmunoassay. The cDNA of Nrg1 is consisted of 2061bp open reading frame encoding 686 amino acids. The deduced amino acid sequence of goose Nrg1 contains one EGF domain from amino acid residues 224 to 265 and shows a closer genetic relationship to the avian species than to other mammal species. The expression level of Nrg1 mRNA increased from the pre-laying period to the peak-laying period, reached its peak in the peak-laying period, and then decreased in the ceased period. The concentrations of FSH and estradiol in blood serum have the similar changing trend. These results might suggest a potential correlation between Nrg1/ErbB signaling network with the reproductive neuroendocrine of Huoyan goose.

The interaction of disrupted type II neuregulin 1 and chronic adolescent stress on adult anxiety- and fear-related behaviors.

The incidence of anxiety, mood, substance abuse disorders and schizophrenia increases during adolescence. Epidemiological evidence confirms that exposure to stress during sensitive periods of development can create vulnerabilities that put genetically predisposed individuals at increased risk for psychiatric disorders. Neuregulin 1 (NRG1) is a frequently identified schizophrenia susceptibility gene that has also been associated with the psychotic features of bipolar disorder. Previously, we established that Type II NRG1 is expressed in the hypothalamic-pituitary-adrenal (HPA) axis neurocircuitry. We also found, using a line of Nrg1 hypomorphic rats (Nrg1(Tn)), that genetic disruption of Type II NRG1 results in altered HPA axis function and environmental reactivity. The present studies used the Nrg1(Tn) rats to test whether Type II NRG1 gene disruption and chronic stress exposure during adolescence interact to alter adult anxiety- and fear-related behaviors. Male and female Nrg1(Tn) and wild-type rats were exposed to chronic variable stress (CVS) during mid-adolescence and then tested for anxiety-like behavior, cued fear conditioning and basal corticosterone secretion in adulthood. The disruption of Type II NRG1 alone significantly impacts rat anxiety-related behavior by reversing normal sex-related differences and impairs the ability to acquire cued fear conditioning. Sex-specific interactions between genotype and adolescent stress also were identified such that CVS-treated wild-type females exhibited a slight reduction in anxiety-like behavior and basal corticosterone, while CVS-treated Nrg1(Tn) females exhibited a significant increase in cued fear extinction. These studies confirm the importance of Type II NRG1 in anxiety and fear behaviors and point to adolescence as a time when stressful experiences can shape adult behavior and HPA axis function.