Nerve growth factor causes epinephrine release dysfunction by regulating phenotype alterations and the function of adrenal medullary chromaffin cells in mice with allergic rhinitis.

The presence of allergic rhinitis (AR) is an increased risk factor for the occurrence of bronchial asthma (BA). Nerve growth factor (NGF), in addition to its key role in the development and differentiation of neurons, may also be an important inflammatory factor in AR and BA. However, the pathogenesis of the progression of AR to BA remains to be elucidated. The present study aimed to investigate the ability of NGF to mediate nasobronchial interactions and explore possible underlying molecular mechanisms. In the present study, an AR mouse model was established and histology of nasal mucosa tissue injury was determined. The level of phenylethanolamine N­methyl transferase in adrenal medulla was determined by immunofluorescence. Primary adrenal medullary chromaffin cells (AMCCs) were isolated and cultured from the adrenal medulla of mice. The expression levels of synaptophysin (SYP), STAT1, JAK1, p38 and ERK in NGF­treated and untreated AMCCs were detected by reverse­transcription­quantitative PCR and western blotting. The epinephrine (EPI) and norepinephrine (NE) concentrations were measured by ELISA. It was found that the expression of SYP in AMCCs was enhanced in the presence of NGF, whereas, the concentration of EPI decreased significantly under the same conditions. Furthermore, NGF mediated the phenotypic and functional changes of AMCCs, resulting in decreased EPI secretion via JAK1/STAT1, p38 and ERK signaling. In conclusion, these findings could provide novel evidence for the role of NGF in regulating neuroendocrine mechanisms.

Serum­derived exosomes from house dust mite­sensitized guinea pigs contribute to inflammation in BEAS­2B cells via the TLR4­NF­κB pathway.

Airway epithelial cells, which are the first physical defense barrier against allergens, play a pivotal role in immunity, airway inflammation and airway remodeling. The damage and dysfunction of these cells trigger the development of airway inflammatory diseases. Exosomes, which exist in various bodily fluids, mediate cell­cell communication and participate in the immune response process. The present study aimed to investigate whether serum exosomes play a pro­inflammatory role in bronchial epithelial cells (BEAS­2B cells) and, if so, explore the underlying molecular mechanisms. A guinea pig model of House dust mite (HDM)­induced asthma was established by sensitizing the rodents with HDM and PBS, and serum­derived exosomes were harvested. It was found that serum­derived exosomes from HDM­sensitized guinea pigs displayed higher levels of exosomal markers than those from controls. Additionally, western blot analysis and reverse transcription­quantitative PCR indicated that serum­derived exosomes from HDM­sensitized guinea pigs carried heat shock protein 70 and triggered an inflammatory response in BEAS­2B cells via the toll­like receptor 4 (TLR4)­NF­κB pathway. However, TAK­242, an inhibitor of the expression of TLR4, blocked the activation of the TLR4­NF­κB pathway. These findings provided a novel mechanism for exosome­mediated inflammatory responses and a new perspective for the intervention of inflammatory airway disorders.

Preventive and therapeutic effect of simvastatin on secondary inflammatory damage of rats with cerebral hemorrhage.

OBJECTIVE: To investigate the preventive and therapeutic effect and mechanism of simvastatin on secondary inflammatory damage of rats with cerebral hemorrhage. METHODS: Sixty SD rat aged 9-12 weeks were chosen and divided into the control group, model group and simvastatin-treated group randomly with 20 rats in each group. Rats in the model group and simvastatin-treated group were infused with autologous fresh uncoagulated blood to the right brain tissue of the basal ganglia to build the cerebral hemorrhage model, while rats in the control group were treated with the same amount of normal saline. Then, rats in the simvastatin-treated group were given a gavage of 3 mg/kg of simvastatin once a day after modeling. Rats in the three groups were given nerve dysfunction score (NDS) and wet-dry weighting method was used to detect the brain water content (BWC) of brain tissues around the lesion of the rats. Then Nissl staining was conducted and the undamaged neurons were counted. Immunohistochemical SP method was applied to count the number of NF-κB, TLR4 and IL-1ß positive cells in brain tissues around the lesions, and the immuno fluorescence method was employed to determine the expression levels of NF-κB, TLR4 and IL-1ß proteins. RESULTS: The NDS results of the simvastatin-treated group at all time points were all significantly higher than those of the model group (P < 0.05); the BWC values of the simvastatin-treated group at all time points were all significantly lower than those of the model group at the same periods (P < 0.05); the number of the undamaged neurons around the lesions of the simvastatin-treated group at all time points were all significantly higher than those of the model group (P < 0.05); seven days after treatment, the number of the NF-κB, TLR4 and IL-1ß positive cells in brain tissues around the lesions of the simvastatin-treated group were all significantly lower than those of the model group (P < 0.05), and its expression levels of NF-κB, TLR4 and IL-1ß protein were also significantly lower than those of the model group (P < 0.05). CONCLUSIONS: Simvastatin can inhibit the expressions of NF-κB, TLR4 and IL-1ß proteins in rats with cerebral hemorrhage, and protect neurons and reduce secondary inflammatory damages by down-regulating the above protein-mediated inflammatory responses.

[P38MAPK pathway regulates COX-2 and caspase-3 expression in a mouse model of Parkinson disease].

OBJECTIVE: To investigate the effect of p38 mitogen-activated protein kinase (p38MAPK) on the expression of COX-2 and caspase-3 in the substania nigra (SN) of mice with MPTP-induced Parkinson disease (PD). METHODS: C57BL/CN mice were treated with MPTP to prepare a subacute PD model, and their behavioral changes following the treatment were observed. Immunohistochemistry and Western blotting were performed to detect the expression of tyrosine hydroxylase (TH), COX-2 and phosphorylation of P38MAPK in the SN and their changes following treatment with SB203580, a specific inhibitor of P38MAPK. RESULTS: The 7-day model group showed typical symptoms of PD with decrements of TH-positive neurons and TH protein level in the SN of the midbrain by about 65% and 75%, respectively (P<0.01). In the 3-day model group, the COX-2-, caspase-3- and phosphorylated P38MAPK-immunoreactive cells and their protein levels in the SN increased markedly with obvious loss of TH-positive neurons. Administration of SB203580 obviously lessened the above changes (P<0.01). CONCLUSION: P38MAPK regulates the inflammation and apoptosis in the SN of the mouse model of subacute PD, and SB203580 may provide some neuroprotective effect.

[Effect of phosphorylated c-Jun expression on COX-2 expression in the substantia nigra of MPTP mouse model of subacute Parkinson disease].

OBJECTIVE: To investigate the effect of phophorylated c-Jun (p-c-Jun) expression on the expression of COX-2 in the substantia nigra (SN) of the MPTP mouse model of subacute Parkinson disease (PD) and explore the possible mechanism of the dopaminergic (DA) neuron death in PD. METHODS: C57BL/6N mice were treated with MPTP to establish subacute PD model. The changes of TH-, COX-2- and p-c-Jun-positive cells, and the expression levels of TH, COX-2 and p-c-Jun in the SN in the midbrain were observed with inmmunohistochemistry and Western blotting before and after administration of SP600125, a specific JNK inhibitor. RESULTS: Compared with the mice in control group, the PD mice exhibited typical symptoms of PD. The number of TH-positive neurons and expression level of TH in the model group were significantly reduced in the substantia nigra by about 65% and 75% (P<0.001) 7 days after the fifth injection of MPTP. The number of COX-2-immunoreactive cells and the expression level of COX-2 were significantly increased. P-c-Jun was specifically expressed in the nuclei of neurons and p-c-Jun expression level was significantly increased in the SN 6 h after the third injection of MPTP. Double-labeling immunofluorescence assay showed coexpression of COX-2 and p-c-Jun in TH-positive neurons in the SN. In mice treated with JNK inhibitor, the number of TH-positive neurons and TH expression level in the SN was only decreased by 15% and 20% as compared with the control group (P<0.001) 7 days after the fifth injection of MPTP, COX-2-positive cell number and COX-2 expression level were obviously reduced as compared with the model group (P<0.001), and p-c-Jun was expressed mainly in the cytoplasm of the neurons whose expression level in SN were significantly decreased 6 h after the third injection of MPTP. The PD mice treated with SP600125 showed slight behavioral symptoms. CONCLUSION: P-c-Jun expression may play an important role in mediating COX-2 expression in the SN in the MPTP model of subacute PD, and inhibiting p-c-Jun activity may provide neuroprotection to the mouse model.