Yiqi Huoxue Tongluo Prescription Inhibits Activation of Astrocytes to Relieve Diabetic Neuropathic Pain in Rats via ERK Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the mechanism of Yiqi Huoxue Tongluo prescription （YHTP） in the treatment of diabetic neuropathic pain （DNP）. MethodNinety SPF-grade SD male rats were randomized into blank， model， low- （2.25 g·kg-1）， medium- （4.5 g·kg-1）， and high-dose （9 g·kg-1） YHTP， and mecobalamin （0.175 mg·kg-1） groups. Except those in the blank group， the rats in the remaining 5 groups were fed with a high-fat and high-glucose diet and subjected to intraperitoneal injection of low-dose （35 mg·kg-1） streptozotocin （STZ） to establish the model of DNP. The sciatic nerve conduction velocity in DNP rats was measured by the neurophysiological method， and the levels of interleukin-6 （IL-6）， IL-1β， and tumor necrosis factor-α （TNF-α） were measured by enzyme-linked immunosorbent assay （ELISA）. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was employed to measure the mRNA levels of glial fibrillary acidic protein （GFAP） and extracellular signal-regulated kinase （ERK） in the spinal cord. Western blot was employed to measure the protein levels of GFAP and phosphorylated ERK （p-ERK）， and immunofluorescence staining to measure the fluorescence intensity of GFAP and p-ERK in the spinal cord. In the cell experiments， 100 mmol·L-1 high glucose was used to induce the activation of astrocytes （CTX-TNA2） for the modeling of nerve cell injury. The cells were randomized into the normal， model， drug-containing serum （10% YQHT）， inhibitor ［10 mol·L-1 corynoxeine （COR）］， drug-containing serum + inhibitor （10% YHTP + 10 mol·L-1 COR） groups. The levels of pro-inflammatory factors （TNF-α and IL-1β） and the anti-inflammatory factor IL-10 in CTX-TNA2 cells were determined by ELISA， and the protein levels of GFAP and p-ERK in CTX-TNA2 cells by Western blot. ResultThe animal experiments showed that compared with the blank group， the model group presented reduced mechanical withdrawal threshold （MWT）， thermal work limit （TWL）， and nerve conduction velocity， elevated levels of fasting blood glucose， IL-1β， TNF-α， and IL-6， and up-regulated protein levels of GFAP and p-ERK， and mRNA levels of ERK1， ERK2， GFAP （P<0.01）. Compared with model group， YHTP increased the MWT， TWL， and sciatic nerve conduction velocity （P<0.01）， lowered the levels of IL-1β， TNF-α， and IL-6 （P<0.01）， and down-regulated the protein levels of GFAP and p-ERK， and mRNA levels of ERK1， ERK2， GFAP in the spinal cord （P<0.05， P<0.01）. The cell experiments showed that compared with the blank group， the model group had decreased survival rate， elevated levels of pro-inflammatory factors， and up-regulated protein levels of ERK and GFAP （P<0.01）. Compared with the model group， the YHTP-containing serum lowered the levels of IL-1β and TNF-α （P<0.05， P<0.01）， elevated the level of IL-10 （P<0.01）， and down-regulated the protein levels of ERK and GFAP （P<0.01）. ConclusionYHTP may inhibit the activation of astrocytes by inhibiting the ERK signaling pathway to reduce inflammation and thus relieve DNP.

Effect of edaravone on ERK-CREB signaling pathway in hippocampus of aged rats with postoperative cognitive dysfunction / 中华麻醉学杂志

Objective:To evaluate the effect of edaravone on the extracellular signal-regulated kinase (ERK)-cAMP responsive element binding protein (CREB) signaling pathway in the hippocampus of aged rats with postoperative cognitive dysfunction (POCD).Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 20 months, weighing 650-700 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), POCD group (group P), edaravone group (group E) and ERK inhibitor group (group I). The rats received laparotomy under 3% sevoflurane anesthesia to prepare POCD model in P, E and I groups. Edaravone 3 mg/kg was intraperitoneally injected at 30 min before operation in E and I groups, ERK inhibitor PD98059 0.3 mg/kg was injected via the tail vein in group I. The open field test was performed at 3 days after operation to evaluate the spontaneous activity of rats, then Morris water maze test was performed to evaluate the cognitive function of rats on 3-7 days after operation. The rats were sacrificed after the end of Morris water maze test, and hippocampal tissues were obtained for determination of the expression of phosphorylated ERK (p-ERK), phosphorylated CREB (p-CREB), synaptophysin and postsynaptic density protein 95 (PSD-95) (by Western blot) and dendrite length and density of dendrites in hippocampal CA1 area (using Golgi staining). Results:Compared with group C, the escape latency was significantly prolonged after operation, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was down-regulated, and the dendritic length and density of hippocampal neurons were reduced in group P ( P<0.05). Compared with group P, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was up-regulated, and the dendritic length and density of hippocampal neurons were increased in group E ( P<0.05). Compared with group E, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was down-regulated, the dendritic length of hippocampal neurons was shortened, and the density of hippocampal neurons was decreased in group I( P<0.05). Conclusions:The mechanism by which edaravone improves POCD may be related to activating ERK/CREB signaling pathway and changing synaptic plasticity in hippocampal CA1 region in aged rats.

Thyroxine promotes the progression of integrin α vβ 3-positive differentiated thyroid cancer through the ERK1/2 pathway / 中华核医学与分子影像杂志

Objective:To explore whether thyroxine (T 4) could promote differentiated thyroid cancer (DTC) progression by binding to integrin α vβ 3in vitro and its downstream mechanism. Methods:Papillary thyroid cancer cell lines TPC-1, K1 and follicular thyroid cancer (FTC) cell line FTC133 were cultured in vitro, and the expressions of integrin α vβ 3 in those 3 DTC cell lines were determined with immunofluorescence and flow cytometry analysis. After the treatment of T 4, tetraiodo thyroacetic acid (Tetrac) and Arg-Gly-Asp (RGD) peptide alone or in combination, the proliferation and metastatic potential of DTC cell lines were detected by cell counting kit-8 (CCK-8), Transwell migration and invasion assays. The small interfering RNA (siRNA) transfection was used to verify whether integrin α v or β 3 subunit knockdown could reverse the effect of T 4 on DTC cells. The expression levels of downstream signaling proteins phosphorylated extracellular signal-regulated kinase (p-ERK)1/2 and total extracellular signal-regulated kinase (ERK)1/2 were detected by Western blot. The effects of mitogen-activated protein kinase kinase (MEK)1/2 inhibitor (GSK1120212) on the proliferation, migration and invasion of T 4-treated cells were detected. One-way analysis of variance and Tukey test were used for data analysis. Results:The integrin α vβ 3 expressions in TPC-1, K1 and FTC133 cells were all positive, with the relative mean fluorescence intensity (MFI) of 61.93±18.61, 16.89±2.43 and 32.36±0.83, and the percentages of positive cells of (94.38±1.30)%, (74.11±3.87)% and (50.67±1.78)%, respectively ( F values: 13.36 and 217.30, P=0.006 and P<0.001). Compared with control group, the proliferation, migration and invasion in the three DTC cell lines treated with T 4 were significantly enhanced (96 h, F values: 62.67-297.50, q values: 13.15-20.73, all P<0.001). T 4-induced cell proliferation, migration and invasion were markedly reversed by Tetrac or RGD (96 h, q values: 8.61-17.54, all P<0.001). T 4-induced cell proliferation, migration and invasion were also significantly inhibited by the knockdown of integrin α v or β 3 subunit (72 h, F values: 7.75-70.98, q values: 4.77-15.21, all P<0.05). Western blot results showed that the phosphorylation levels of ERK1/2 in DTC cells were significantly increased by T 4 treatment, and the T 4-induced activation of ERK1/2 signaling pathway could be blocked by Tetrac, RGD, integrin α v or β 3 subunit knockdown. T 4-induced cell proliferation, migration and invasion were significantly reversed by GSK1120212 (96 h, F values: 47.53-151.40, q values: 10.32-16.65, all P<0.001). Conclusion:T 4 can promote cell proliferation and metastasis of DTC cells by binding to integrin α vβ 3 and activating the ERK1/2 pathway.

Protective role of vasonatrin peptide in hepatic ischemia-reperfusion injury in rats through activation of extracellular signal-regulated kinase signaling pathway / 中华肝胆外科杂志

Objective:To investigate the protective role of extracellular signal-regulated kinase (ERK) signaling pathway in the process that vasonatrin peptide (VNP) reduces hepatic ischemia-reperfusion injury in rats.Methods:Twenty SD rats, weighting 200-250 g, were randomly divided into four groups and each group has five rats. The four groups were sham operation group (S group), ischemia-reperfusion group (I/R group), VNP group (V group) and PD98059+ VNP group (P+ V group). In the rat model of hepatic warm ischemia and reperfusion, the hepatic artery and portal vein of the left lobe and middle lobe of the liver were clamped with arterial clamp for 45 min followed by reperfusion for 120 min. In the V group, VNP (50 μg/kg) was injected 10 minutes before ischemia. In the P+ V group, PD98059 (2 mg/kg) was injected 20 min before VNP injection followed by VNP administration and I/R treatment. The serum levels of alanine amino transaminase (ALT), aspartate amino transferase (AST), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and the superoxide dismutase (SOD) in liver tissue homogenate and malondialdehyde (MDA) were measured. The histopathology of liver tissue was observed. The contents of p-ERK1/2 were detected by Western blot.Results:Compared with S group, in I/R group and P+ V group the serum levels of ALT [(489.65±11.22), (333.05±24.77) vs. (33.78±4.88) U/L], AST [(651.43±14.99), (503.18±21.48) vs. (154.84±12.32) U/L], TNF-α [(12.83±1.09), (9.64±0.57) vs. (2.11±0.11) ng/L], IL-1β [(7.19±0.62), (5.12±0.22) vs. (1.10±0.49) ng/L], MDA [(8.00±0.88), (5.60±1.01) vs. (2.76±1.29) μmol/mg] increased, while SOD [(54.89±10.60), (68.85±8.33) vs. (126.10±15.63) nmol/mg]decreased (all P<0.05). The histopathology of liver tissue revealed that liver structure damaged more seriously in I/R group and P+ V group. Western blot analysis showed that p-ERK1/2 decreased significantly in I/R group and P+ V group. Compared with I/R group, ALT, AST, MDA, TNF-α and IL-1β decreased significantly and SOD increased significantly in V group (all P<0.05). The histopathology of liver tissue revealed that liver structure was damaged slightly, and p-ERK1/2 increased significantly in V group compared with I/R group ( P<0.05). Conclusion:VNP can significantly reduce hepatic ischemia-reperfusion injury through activation of p-ERK1/2 signaling pathway and inhibition of hepatocyte inflammatory response.

Chinese Medicines Regulate p38 MAPK， ERK1/2， and JNK in Treatment of Osteoporosis： A Review / 中国实验方剂学杂志

With the aging of population， osteoporosis has become one of the main diseases endangering the health of the elderly in China. Therefore， the research on osteoporosis has become a hot spot. Since Chinese medicines demonstrate significant therapeutic effects on osteoporosis， this issue is attracting increasing attention from researchers， especially in the deciphering of the molecular mechanism. This paper introduces the mechanism of the prevention and treatment of osteoporosis by Chinese medicines via the mitogen-activated protein kinase （MAPK） signaling pathway， aiming to provide a theoretical basis for deciphering the mechanism of Chinese medicines in the treatment of osteoporosis and promoting their clinical application. MAPK signaling pathway mainly involves p38 MAPK， extracellular signal-regulated kinase 1/2 （ERK1/2）， c-Jun N-terminal kinase （JNK）， and extracellular signal-regulated kinase 5 （ERK5）. Studies have shown that these proteins play a role in the progression of osteoporosis by regulating cell proliferation， differentiation， and apoptosis. Chinese medicines as a unique therapy with Chinese characteristics has definite efficacy， high safety， and mild side effects. Researchers have proved by experiments that the extracts or compounds of Chinese medicines can significantly mitigate osteoporosis by regulating the proteins involved in the MAPK signaling pathway. Therefore， this article reviews the relevant studies with focus on these proteins.

Effect of Yanghetang-containing Serum on Breast Cancer 4T1 Cells Based on MEK/ERK Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the effects of Yanghetang （YHT） on breast cancer 4T1 cells and their mitogen-activated protein kinase （MEK）/extracellular signal-regulated kinase （ERK） signaling pathway. MethodThe YHT-containing serum was prepared from SD rats. The rats were randomly assigned into a blank group （normal saline） and low-， medium-， and high-dose （5.8， 11.6， 23.2 g·kg-1， respectively） YHT groups. The serum containing 10% YHT in each group was mixed with 90% RMPI 1640 complete medium， and the mixture was used to interfere with the cells. Cell counting kit-8 （CCK-8） method was used to detect the proliferation of the 4T1 cells treated with YHT for 24， 48， 72 h. The apoptosis， migration， and invasion of 4T1 cells were detected by flow cytometry， scratch test， and Transwell assay， respectively. Western blot was employed to determine the expression levels of MEK1/2， phosphorylation （p）-MEK1/2， ERK1/2， p-ERK1/2， and rat sarcoma virus （RAS） protein. ResultCompared with the blank group， the intervention with YHT-containing serum for 24， 48， and 72 h had significant inhibitory effect on 4T1 cell proliferation （P<0.05， P<0.01）. After intervention with YHT-containing serum for 48 h， the apoptosis rate of cells increased （P<0.01）. Compared with the blank group， the intervention with YHT for 24 h and 48 h decreased the healing ability of cells in the scratch test （P<0.01）. The invasive ability of cells treated with the low， medium， and high-dose YHT containing serum showed a decreasing trend （P<0.01）. Compared with the blank group， YHT-containing serum did not change the expression of MEK1/2 and ERK1/2 while down-regulating the expression of p-MEK1/2， p-ERK1/2， and RAS protein （P<0.01）. ConclusionYHT can inhibit the proliferation， migration， and invasion and promote the apoptosis of breast cancer 4T1 cells. In may promote the apoptosis by inhibiting the MEK/ERK signaling pathway and down-regulating the expression of p-MEK1/2， p-ERK1/2， and RAS protein.

Apolipoprotein E enhances migration of endometrial cancer cells byactivating the ERK/MMP9 signaling pathway / 南方医科大学学报

OBJECTIVE@#To study the role of apolipoprotein E (APOE) in regulating endometrial cancer metastasis and explore the signaling pathway in the regulatory mechanism.@*METHODS@#Human endometrial cancer cell line HEC-1B was transfected with a control siRNA (siCtrl) or a specific siRNA targeting APOE (siAPOE) or with either pEGFP-N1 plasmid or an APOEoverexpressing plasmid. The changes in migration, proliferation, apoptosis and cell cycle of the transfected cells were examined using wound healing assay, Transwell migration assay, MTT assay, flow cytometry, and Hoechst staining. The activity of the ERK/MMP9 signaling pathway in the transfected cells was assessed using RT-qPCR and Western blotting. The expression level of APOE in clinical specimens of endometrial cancer tissues were detected using immunohistochemistry and its correlation with differentiation of endometrial cancer tissues was analyzed.@*RESULTS@#Wound healing assay and Transwell migration assay showed that compared with those in siCtrl group, HEC-1B cells transfected with siAPOE showed significantly reduced migration ability (P < 0.05), whereas APOE overexpression significantly promoted the migration of the cells (P < 0.05). Neither APOE knockdown nor overexpression produced significant effects on HEC-1B cell proliferation as shown by MTT assay and flow cytometry. Hoechst staining revealed that transfection with siAPOE did not significantly affect apoptosis of HEC-1B cells. APOE knockdown obviously reduced and APOE overexpression enhanced ERK phosphorylation and MMP9 expression in HEC-1B cells (P < 0.05). Treatment with U0126 partially reversed the effects of APOE overexpression on ERK phosphorylation, migration and MMP9 expression in HEC-1B cells (P < 0.05). APOE is highly expressed in clinical samples of endometrial cancer tissues as compared with the adjacent tissues.@*CONCLUSION@#APOE is highly expressed in endometrial cancer tissues to promote cancer cell migration by enhancing ERK phosphorylation and MMP9 expression.

Study on the anti-pulmonary fibrosis effect of linarin in vivo and in vitro and its mechanism / 中国药房

OBJECTIVE To investigate the anti-pulmonary fibrosis effect of linarin in vivo and in vitro， and investigate its mechanism preliminarily. METHODS C57BL/6J mice were randomly divided into normal group （carboxymethylcellulose sodium）， model group （carboxymethylcellulose sodium）， positive control group （pirfenidone， 200 mg/kg）， linarin low-dose and high-dose groups （12.5， 25 mg/kg）， with 8 mice in each group. Except for normal group， pulmonary fibrosis model was induced in other groups. After modeling， they were given relevant medicine intragastrically， once a day， for consecutive 14 d. The general situation of mice was observed， and their lung indexes were measured； the levels of tumor necrosis factor-α （TNF-α） and transforming growth factor-β1（ TGF-β1） in serum and interleukin-6 （IL-6） in lung tissue were determined. Hematoxylin-eosin （HE） staining and Masson staining were used to observe the histopathological morphology of lung. The pulmonary fibrosis was scored according to Ashcroft score standard. The expressions of α-smooth muscle actin （α-SMA） and （type Ⅰ collagen， Collagen Ⅰ）， phosphorylated extracellular signal-regulated kinase （p-ERK1/2） and TGF-β1 in lung tissues were detected. HFL1 cells were stimulated by TGF- β1 to form pulmonary fibrosis model in vitro， which were divided into normal group， model group and linarin low-， medium- and high-concentration groups （3.7， 7.4， 14.8 mg/L）. After being cultured for 48 h， the protein expressions of α-SMA， Collagen Ⅰ and p-ERK1/2 in HFL1 cells were detected. RESULTS In vivo， compared with normal group， the lung index of model group and the levels of TNF- α， TGF- β1 and IL-6 were significantly increased （P＜0.01）. There were a large number of inflammatory infiltration and cellular fibrosis lesions in the alveoli， and a large number of collagen depositions. The scores of HE staining and Masson staining were significantly increased （P＜0.01）. The protein expressions of α-SMA， Collagen Ⅰ， p-ERK1/2 and TGF-β1 in lung tissue were up-regulated significantly （P＜0.01）. Compared with model group， above indexes of mice were improved significantly in linarin high-dose group （P＜0.05 or P＜0.01）， and most of indexes （except for lung index） were improved significantly in linarin low-dose group （P＜0.05 or P＜0.01）. In vitro， compared with blank group， the density of cells in the model group increased， and obvious proliferation and other changes occurred； protein expressions of α-SMA， Collagen Ⅰ and p-ERK1/2 were significantly up-regulated （P＜0.05 or P＜0.01）. Compared with model group， the cell density of each concentration group was decreased and the morphology gradually returned to normal； the expressions of above proteins in linarin high-concentration group and the protein expression of p-ERK1/2 in linarin medium-concentration group were down-regulated significantly（P＜0.05 or P＜0.01）. CONCLUSIONS Linarin may regulate ERK and inflammatory pathways to reduce the inflammatory response， thereby exerting anti-pulmonary fibrosis effect.

Extracellular Signal-regulated Kinase 1/2 Signaling Regulates Cell Invasion:a Review / 中国医学科学院学报

Extracellular signal-regulated kinase 1/2 (ERK1/2) is a serine/threoninekinase involved in the signal transduction cascade of Ras-Raf-mitogen-activated protein kinase (MEK)-ERK.It participates in the cell growth,proliferation and even invasion by regulating gene transcription and expression.The occurrence of a variety of diseases such as lung cancer,liver cancer,ovarian cancer,cervical cancer,endometriosis,and preeclampsia,as well the metastasis and disease progression,is closely associated with the regulation of cell invasion by ERK1/2 signaling pathway.Therefore,exploring the regulation of ERK1/2 signaling on cell invasion and its role in pathogenesis of diseases may help to develop more effective treatment schemes.This article introduces recent progress in the regulation of ERK1/2 signaling on cell invasion and the role of such regulation in diseases,with a view to give new insights into the clinical treatment of ERK 1/2-related diseases.

Effect of extracellular signal-regulated kinase inhibitor on calpain in rat cerebral cortex after cardiopulmonary resuscitation / 中华危重病急救医学

Objective:To explore the effect of extracellular signal-regulated kinase (ERK) inhibitor PD98059 on calpain-related proteins in the brain, and to understand the pathophysiological changes of calpain in cerebral ischemia/reperfusion injury (CIRI).Methods:Forty-two rats were divided into sham operation (Sham) group ( n = 6), model group ( n = 12), dimethyl sulfoxide (DMSO) control group ( n = 12), and PD98059 group ( n = 12) by random number table. The rat model of CIRI induced by cardiac arrest-cardiopulmonary resuscitation (CA-CPR) was reproduced by transesophageal electrical stimulation to induce ventricular fibrillation. In the Sham group, only the basic operations such as anesthesia, tracheal intubation, and arteriovenous catheterization were performed without CA-CPR. The rats in the DMSO control group and PD98059 group were injected with DMSO or PD98059 0.30 mg/kg via femoral vein, respectively, 30 minutes after the restoration of spontaneous circulation (ROSC), and rats in the Sham group and model group were given the same amount of normal saline. The duration of CPR, 24-hour survival rate and neurological deficit score (NDS) after ROSC were recorded. Hematoxylin-eosin (HE) staining and Nissl staining were used to observe the pathological changes of the cerebral cortex. The expressions of phosphorylated ERK (p-ERK), ERK, calpastatin, calpain-1, and calpain-2 were detected by Western blotting. The co-expression of p-ERK and calpain-2 was detected by double immunofluorescence. Results:There were no significant differences in the duration of CPR and 24-hour survival rate among all groups. In the model group, the nuclei of the cerebral cortex were obviously deformed and pyknotic, cells vacuoles and tissues were arranged disorderly, Nissl corpuscles were significantly reduced, NDS scores were also significantly reduced, level of ERK phosphorylation was increased, and calpain-2 protein was significantly up-regulated compared with the Sham group. There was no significant difference in the above parameters between the DMSO control group and the model group. After intervention with PD98059, the pathological injury of brain tissue was significantly improved, Nissl corpuscles were significantly increased, the NDS score was significantly higher than that in the model group [75.0 (72.0, 78.0) vs. 70.0 (65.0, 72.0), P < 0.05], the level of ERK phosphorylation and calpain-2 protein expression were significantly lower than those in the model group [p-ERK (p-ERK/ERK): 0.65±0.12 vs. 0.92±0.05, calpain-2 protein (calpain-2/GAPDH): 0.73±0.10 vs. 1.07±0.14, both P < 0.05], while there was no significant difference in the expressions of calpastatin and calpain-1 in the cerebral cortex among all the groups. Double immunofluorescence staining showed that p-ERK and calpain-2 were co-expressed in cytosol and nucleus, and the co-expression rate of p-ERK and calpain-2 in the model group was significantly higher than that in the Sham group [(38.6±4.3)% vs. (9.2±3.5)%, P < 0.05], while it was significantly lowered in the PD98059 group compared with the model group [(18.2±7.0)% vs. (38.6±4.3)%, P < 0.05]. Conclusions:ERK together with calpain-2 participated in CIRI induced by CA-CPR. PD98059 inhibited the expression of calpain-2 and ERK phosphorylation. Therefore, ERK/calpain-2 may be a novel therapeutic target for CIRI.

Effect of Shufeng Tongluo Prescription on Eotaxin and CCR3 Protein Expression and ERK Phosphorylation Level of Asthma Mice / 中国实验方剂学杂志

ObjectiveTo preliminarily explore the mechanism of Shufeng Tongluo prescription （SFTLP） in inhibiting airway inflammation in asthma mice by affecting the expression levels of eotaxin in the serum， CC type chemokine receptor 3 （CCR3）， and extracellular signal-regulated kinase （ERK） phosphorylation in lung tissues. MethodSeventy C57BL/6 mice were randomly divided into a blank group， a model group， low-， medium-， and high-dose SFTLP groups （7.75， 15.5， 30 g·kg-1）， a pertussis toxin （PTX） group， a CCR3 inhibitor （SB328437） group， a phosphoinositide 3-kinase （PI3K） inhibitor （LY294002） group， a p38 protein kinase antagonist inhibitor （SB203580） group， and an ERK inhibitor （PD98059） group. The asthma model was induced in mice by intraperitoneal injection of ovalbumin （OVA） and aluminum hydroxide ［Al（OH）3］ combined with OVA atomization （0.2 mL for all）. After modeling， hematoxylin-eosin staining （HE staining） was used to observe the inflammatory infiltration of lung tissues in mice. Enzyme-linked immunosorbent assay （ELISA） was used to detect the serum levels of eotaxin ［CC chemokine ligand （CCL） 11 and CCL24） in each group. Western blot was used to detect the levels of ERK phosphorylation and CCR3 in lung tissues. ResultCompared with the blank group， the model group showed obvious bronchial constriction， lumen stenosis， damaged alveolar structure， massive inflammatory cell infiltration in lung tissues， mucous plug in the bronchus， edema in the submucosal tissues of the trachea， increased folds， increased serum levels of CCL11 and CCL24 （P<0.01）， and increased expression of CCR3 protein in lung tissues （P<0.05）. The ERK levels in lung tissues of the model group and the PTX group increased （P<0.05）. The level of p-ERK in lung tissues of the model group and the low-dose SFTLP group increased （P<0.05）. As revealed by pathological results， compared with the model group， the high-dose SFTLP group showed relieved lung lesions. The high-dose SFTLP group and the SB328437 group showed reduced CCL11 content （P<0.05）. The low- and high-dose SFTLP group， the PTX group， the SB203580 group， the PD98059 group， and the SB328437 group showed decreased CCR3 protein expression in lung tissues （P<0.05）. The high-dose SFTLP group and the PD98059 group showed reduced p-ERK level （P<0.05）. The PD98059 group showed reduced ERK level （P<0.05）. ConclusionSFTLP can inhibit airway inflammation in asthma， and the mechanism may be related to the inhibition of eosinophil activation by down-regulating CCR3 and CCL11 expression and ERK phosphorylation.

Effect of rat cardiac fibroblasts on expression of Cx43 in H9c2 cells during hypothermic hypoxia/reoxygenation / 中华麻醉学杂志

Objective:To evaluate the effect of rat cardiac fibroblasts (RCF) on the expression of connexin43 (Cx43) in H9c2 cells during hypothermic hypoxia/reoxygenation.Methods:H9c2 cells cultured in vitro were divided into 4 groups ( n=12 each) using the random number table method: control group (group C), hypothermic hypoxia/reoxygenation group (group HHR), RCF co-culture group (group Co) and RCF co-culture plus hypothermic hypoxia/reoxygenation group (group Co+ HHR). Group C was incubated at 37℃ in 5% CO 2 + 95% air for 5 h. Group HHR was incubated at 4 ℃ in 5% CO 2 + 95% N 2 for 1 h and then at 37 ℃ in 5% CO 2 + 95% air for 4 h. In group Co and group Co+ HHR, H9c2 cells 0.3×10 5 cells/well were inoculated in the lower chamber and RCF 0.6×10 5 cells/well in the the upper chamber of a transwell ? culture dish.Group Co was incubated at 37 ℃ in 5% CO 2 + 95% air for 5 h. Group Co+ HHR was incubated at 4℃ in 95% N 2 + 5% CO 2 for 1 h, and then incubated at 37 ℃ in 5% CO 2 + 95% air for 4 h. The mortality rate of H9c2 cells was measured by trypan blue staining, the expression of Cx43 and extracellular signal-regulated protein kinases 1/2 (ERK1/2) by immunofluorescence, and the expression of Cx43, phosphorylated Cx43, ERK1/2 and phosphorylated ERK1/2 by Western blot. Results:Compared with group C, the mortality rate of H9c2 cells was significantly increased, the expression and phosphorylation of Cx43 were decreased, and the expression and phosphorylation of ERK1/2 were increased in group HHR ( P<0.05), and no significant change was found in the mortality rate of H9c2 cells or expression and phosphorylation of Cx43 and ERK1/2 in group Co ( P>0.05). Compared with group Co, the mortality rate of H9c2 cells was significantly increased, and the expression and phosphorylation of Cx43 and ERK1/2 were decreased in group Co+ HHR ( P<0.05). Compared with group HHR, the mortality rate of H9c2 cells was significantly increased, and the expression and phosphorylation of Cx43 and ERK1/2 were decreased in group Co+ HHR ( P<0.05). Conclusions:RCFs can decrease the expression and activity of Cx43 in H9c2 cells during hypothermic hypoxia/reoxygenation, and the mechanism may be related to the down-regulation of ERK1/2 expression and inhibition of ERK1/2 activity.

Development of small molecule extracellular signal-regulated kinases (ERKs) inhibitors for cancer therapy

The mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway is widely activated by a variety of extracellular stimuli, and its dysregulation is associated with the proliferation, invasion, and migration of cancer cells. ERK1/2 is located at the distal end of this pathway and rarely undergoes mutations, making it an attractive target for anticancer drug development. Currently, an increasing number of ERK1/2 inhibitors have been designed and synthesized for antitumor therapy, among which representative compounds have entered clinical trials. When ERK1/2 signal transduction is eliminated, ERK5 may provide a bypass route to rescue proliferation, and weaken the potency of ERK1/2 inhibitors. Therefore, drug research targeting ERK5 or based on the compensatory mechanism of ERK5 for ERK1/2 opens up a new way for oncotherapy. This review provides an overview of the physiological and biological functions of ERKs, focuses on the structure-activity relationships of small molecule inhibitors targeting ERKs, with a view to providing guidance for future drug design and optimization, and discusses the potential therapeutic strategies to overcome drug resistance.

Changes in circadian gene cryptochrome 2 expression in mouse models of psoriasis and HaCaT cells and their underlying mechanisms / 中华皮肤科杂志

Objective:To investigate changes in circadian gene cryptochrome 2 (CRY2) expression in mouse models of psoriasis and HaCaT cells, and to explore underlying mechanisms.Methods:Imiquimod-induced mouse model experiment: 12 C57BL/6 female mice were randomly and equally divided into imiquimod group receiving topical imiquimod treatment for 5 consecutive days and control group receiving no treatment; these mice were sacrificed on day 6, skin tissues were resected from the back of mice, and immunofluorescence staining was performed to determine the CRY2 expression in the epidermis. HaCaT cell transfection experiment: HaCaT cells with small interfering RNA (siRNA) -mediated knockdown of CRY2 served as siRNA-CRY2 group, and siRNA-NC group as control group; 5-ethynyl-2′-deoxyuridine (EdU) staining was performed to evaluate the proliferative activity of the HaCaT cells, real-time fluorescence-based quantitative PCR (qPCR) to determine the mRNA expression of chemokines in the HaCaT cells, and Western blot analysis to determine phosphorylation levels of extracellular signal-regulated kinase 1/2 (ERK1/2) . Tumor necrosis factor-α (TNF-α) -stimulated animal and cell experiments: 12 C57BL/6 female mice were randomly and equally divided into TNF-α group subcutaneously injected with TNF-α solution in the ear for 6 days, and phosphate buffered saline (PBS) group subcutaneously injected with the same amount of PBS; the mice were sacrificed on day 7, skin tissues were resected from the ear of mice, and immunofluorescence staining was conducted to determine the CRY2 expression in the epidermis; CRY2-knockdown HaCaT cells stimulated with 50 ng/ml TNF-α for 12 hours served as siRNA-CRY2 + TNF-α group, and siRNA-NC + TNF-α group as control group; qPCR was performed to determine the mRNA expression of chemokines in HaCaT cells in the above groups. Statistical analysis was carried out by using two-independent-sample t test. Results:Immunofluorescence staining showed that the CRY2 protein expression was significantly lower in the mouse dorsal epidermis in the imiquimod group (0.94 ± 0.23) than in the control group (2.30 ± 0.25, t = 3.99, P = 0.016) . Compared with the siRNA-NC group, the siRNA-CRY2 group showed significantly increased proportions of EdU-positive cells (48.13% ± 10.97% vs. 38.23% ± 0.81%, t = 5.00, P = 0.007) , mRNA expression levels of chemokines CXCL1 and CXCL8, as well as significantly increased phosphorylated (p) -ERK1/2 protein expression levels (all P < 0.05) , while there were no significant differences in the CCL20 mRNA expression or ERK1/2 protein expression between the two groups (both P > 0.05) . Immunofluorescence staining showed significantly decreased CRY2 protein expression level in the mouse ear epidermis in the TNF-α group (0.37 ± 0.34) compared with the PBS group (2.04 ± 0.17, t = 4.38, P = 0.012) ; the relative mRNA expression levels of chemokines CXCL1, CXCL8, and CCL20 in HaCaT cells were significantly higher in the siRNA-CRY2 + TNF-α group than in the siRNA-NC + TNF-α group (all P < 0.05) . Conclusion:CRY2 was markedly underexpressed in psoriasis, which might promote the proliferation of keratinocytes and expression of chemokines CXCL1, CXCL8 and CCL20, and TNF-α might be an upstream cytokine that could downregulate CRY2 expression.

Preliminary study on the expression of MIF in HCC tissues and its relationship with ERK1/2 signaling pathway / 中华内科杂志

Objective:To investigate the expression of Macrophage migration-inhibitory factors (MIF) in hepatocellular carcinoma (HCC) tissues and its interaction with ERK1/2 signaling pathway, so as to establish a theoretical basis for further studying the molecular mechanism of MIF promoting HCC.Methods:From February 2020 to August 2021, 52 cases of hepatocellular carcinoma (HCC) tissues based on hepatitis B cirrhosis (HBV-LC) and 52 cases of adjacent tissues in Tianjin Medical University Cancer Hospital and 940th Hospital of Joint Logistic Support Force of PLA were collected as the experimental group, including 39 males and 13 females, aged 35-65 years. And 20 cases of normal liver tissue were selected as the control group. Immunohistochemistry was used to detect the expression of MIF, ERK1/2 and p-ERK1/2 proteins in liver tissues of the two groups, and in situ hybridization was used to detect the expression of ERK1/2 nucleic acid in liver tissues of the two groups.HepG2 HCC cells and L-02 normal hepatocytes were co-cultured with different concentrations of rMIF, the expression and phosphorylation levels of ERK1/2 and JNK1 proteins in the two kinds of liver cells were detected by Western-blot, and the expression levels of ERK1/2 nucleic acids in the two kinds of liver cells were detected by RT-PCR. One-way ANOVA was used for measurement data and χ 2 test was used for counting data. Results:The expressions of MIF, ERK1/2, p-ERK1/2 and ERK1/2 mRNA were significantly increased in HCC and para-cancer tissues (the expression of MIF in HCC group was 78.8%, and that in adjacent group was 75.0%; ERK1/2 80.8% in HCC group and ERK1/2 71.8% in paracancerous group. The expression of p-ERK1/2 75.0 % in HCC group and 46.2% in paracancerous group were respectively detected. ERK1/2 mRNA was expressed in HCC group 76.9%, ERK1/2 mRNA expression in paracancerous group 78.8%), and the differences were statistically significant compared with normal liver tissues ( P<0.05), but there was no significant difference between HCC and para-cancer tissues ( P>0.05). The expressions of ERK1/2, p-ERK1/2 and ERK1/2 mRNA in HepG2 HCC cells were significantly increased with the increase of rMIF concentration, and the increase was most obvious when rMIF concentration was 200 ng/ml, and the difference was statistically significant compared with L-02 normal hepatocytes ( P<0.05). Conclusion:MIF, ERK1/2 and p-ERK1/2 are highly expressed in HCC tissues and HepG2 HCC cells, suggesting that MIF promotes the occurrence and development of hepatocellular carcinoma through ERK1/2 signaling pathway.

Repair effect and mechanism of neural cell adhesion molecule derived peptide P2 on nerve function injury in ischemic stroke rats / 中华行为医学与脑科学杂志

Objective:To clarify the neuroprotective effects of neural cell adhesion molecule (NCAM) derived peptide P2 on in vitro cultured neuron and ischemic stroke rat. Methods:Primary cortical neurons were extracted and cultured, and CCK-8 method was used to observe the protective effect of different concentrations of P2 on cortical neurons under oxygen-glucose deprivation (OGD) conditions.The levels of apoptosis-related proteins and extracellular signal regulated kinase 1/2 (Erk1/2) were observed by Western blot. Clean grade male SD rats were selected for animal experiments. The middle cerebral artery occlusion (MCAO) method was used to establish the rat model of cerebral ischemia/reperfusion injury. The rats with successful model were divided into sham operation group, MCAO group and MCAO+ P2 group according to the random number table, with 12 rats in each group. After operation, rats in MCAO+ P2 group were subcutaneously injected with 1 mg/kg P2 once a day until 14 days after operation, and rats in the other two groups were subcutaneously injected with 0.9% sodium chloride solution of the same volume.Beam-walking test was used to evaluate the motor function of rats.Immunofluorescence staining and Western blot were used to detect the in-situ apoptosis of neuronal cells and the expression of Erk1/2 in ischemic penumbra of rat brains, respectively. All statistical analyses were performed using SPSS 22.0.Repeated measurement ANOVA was used to evaluate the beam-walking experimental data, and one-way ANOVA were used to analyze other experimental data among multiple groups.Results:Compared with OGD group, 0.5, 1.0 and 2.0 μmol/L P2 improved the activity of neurons under OGD conditions, of which 1 μmol/L P2 had the best effect ((2.436±0.284), (1.551±0.410), P<0.05). Western blot showed that the protein levels of bax ((76.120±3.232)%, (88.965±5.208)%, P<0.05), cleaved caspase-3 ((76.736±4.306)%, (97.781±8.111)%, P<0.05) and cleaved caspase-9 ((88.833±6.581)%, (104.962±4.788)%, P<0.05) in 1 μmol/L P2 treated group were all lower than those in OGD group, while the protein levels of bcl-2 ((56.146±3.882)%, (43.170±6.945)%, P<0.05) and phosphorylated Erk1/2 ((73.583±8.557)%, (55. 219±4.615)%, P<0.05) in 1 μmol/L P2 treated group were both higher than those in OGD group. Compared with MCAO group, on the 14th day after P2 intervention, the slip ratio of hindlimb of the paralyzed hind limbs of rats was lower ((23.438±11.540)%, (41.733±13.631)%, P<0.05), the apoptosis rate of neurons around the focus was lower ((13.144±6.485)%, (26. 699±6. 402)%, P<0.05), and the level of phosphorylated Erk1/2 protein in the brain tissues around the infarct focus was higher ((74.062±7.458)%, (53.327±7.093)%, P<0.05). Conclusion:Low doses of neural cell adhesion molecule derived peptide P2 exert neuroprotective effects on OGD neurons and ischemic stroke rats. The underlying mechanism may be related to the activation of Erk.

Hippocampus is involved in 17β-estradiol exacerbating experimental occlusal inter- ference-induced chronic masseter hyperalgesia in ovariectomized rats / 北京大学学报(医学版)

OBJECTIVE@#To investigate the influence of chronic masseter hyperalgesia induced by 17β-estradiol (E2) and experimental occlusal interference (EOI) on underlying mechanism in hippocampus of ovariectomized (OVX) rats.@*METHODS@#In the study, 32 OVX rats were randomly divided into 4 groups (8 rats/group): The control group was OVX group, and 0 μg/d E2 (vehicle) injection was started 7 d after OVX without EOI; in the experimental group (1) OVX + E2 group, 80 μg/d E2 injection was started 7 d after OVX without EOI; in the experimental group (2) OVX + EOI group, vehicle injection was started 7 d after OVX and EOI was applied 17 d after OVX; in the experimental group (3) OVX + E2 + EOI group, 80 μg/d E2 injection was started 7 d after OVX and EOI was applied 17 d after OVX. Bilateral masseter muscle mechanical withdrawal thresholds were measured before OVX, 7 days after OVX (before E2 injection), 17 days after OVX (10 days after E2 injection and before EOI) and 24 days after OVX (7 days after EOI). Immunofluorescence staining was used to reveal phospho-extracellular signal regulated kinase 1/2 (p-ERK1/2)-positive neurons in CA3 of hippocampus. The protein expression of p-ERK1/2 in hippocampus was detected using Western Blot.@*RESULTS@#Compared with the control group [left side: (135.3±8.5) g, right side: (135.4±10.8) g], bilateral masseter muscle mechanical withdrawal thresholds of OVX+E2 group [left side: (113.3±5.6) g, right side: (112.5 ± 5.6) g] and OVX+EOI group [left side: (93.3±5.4) g, right side: 90.8±5.5) g] were decreased (P < 0.01). Bilateral masseter muscle mechanical withdrawal thresholds were significantly lower in OVX+E2+EOI group [left side: (81.2±6.2) g, right side: 79.8±7.7) g] than in the control, OVX+E2 and OVX+EOI groups (P < 0.05). The proportion of p-ERK1/2 positive neurons in the CA3 region of the hippocampus was increased in the control, OVX+E2, OVX+EOI and OVX+E2+EOI groups in turn, and the difference between the groups was statistically significant (P < 0.05). p-ERK1/2 protein expression was increased in the control, OVX+E2 and OVX+EOI groups in turn, but the difference was not statistically significant (P>0.05). p-ERK1/2 expression was significantly higher in OVX+E2+EOI group than in the other three groups (P < 0.05).@*CONCLUSION@#High concentration of E2 could exacerbated EOI-induced chronic masseter hyperalgesia in ovariectomized rats, and its central mechanism may be related to the upregulation of the phosphorylation of ERK1/2 in hippocampus.

Protective effect of adrenomedullin on hyperoxia-induced lung injury / 中国当代儿科杂志

OBJECTIVES@#To study the role of adrenomedullin (ADM) in hyperoxia-induced lung injury by examining the effect of ADM on the expression of calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein 2 (RAMP2), extracellular signal-regulated kinase (ERK), and protein kinase B (PKB) in human pulmonary microvascular endothelial cells (HPMECs) under different experimental conditions.@*METHODS@#HPMECs were randomly divided into an air group and a hyperoxia group (@*RESULTS@#Compared with the air group, the hyperoxia group had significant increases in the mRNA and protein expression levels of ADM, CRLR, RAMP2, ERK1/2, and PKB (@*CONCLUSIONS@#ERK1/2 and PKB may be the downstream targets of the ADM signaling pathway. ADM mediates the ERK/PKB signaling pathway by regulating CRLR/RAMP2 and participates in the protection of hyperoxia-induced lung injury.

Effect of Notoginseng Total Saponins on Changing Multidrug Resistance in HepG2/ Adriamycin Cells Through ERK/Akt Signaling / 中国实验方剂学杂志

Objective:To investigate the effect of notoginseng total saponins （TNS） on adriamycin （Adr） resistance in HepG2/Adr cells and the expression and activity of the mechanisms as the modulators of multi-drug resistance， so as to explore the possible mechanism of extracellular signal-regulated kinase （ERK） and protein kinase B （Akt） signaling pathways in reversing the resistance of HepG2/Adr cells mechanism. Method:Effect of TNS on HepG2/Adr cell proliferation was detected by thiazole blue （MTT） method. HepG2/Adr cells were treated with different concentrations （100， 50， 25， 0 mg·L^-1） of TNS and （20 μmol·L^-1） Adr respectively， and a blank group was set. The high-content screening platform was used to detect the accumulation of Adr in HepG2/Adr cells after 40 minutes， 3 hours and 6 hours. Western blot was used to detect the expression of P-glycoprotein /multidrug resistance/ATP binding cassette subfamily B member 1（P-gp/MDR1/ABCB1） and other drug resistance-related proteins and the main protein expression of ERK/Akt signaling pathway. The change of MDR1 on cell membranes was observed by laser confocal microscopy. Result:Compared with HepG2 cells， the expression of MDR1 in HepG2/Adr cells was significantly increased （<italic>P</italic><0.01）. Compared with the Adr group， the half-inhibitory concentration （IC₅₀） of TNS （25， 50， 100 mg·L^-1） and Adr （20 μmol·L^-1） co-administration group on HepG2/Adr cells <italic>in vitro</italic> significantly reduced （<italic>P</italic><0.01）， and the highest reversal multiple was 10 times. Compared with the Adr group， the co-administration group could significantly increase the accumulation of Adr in the cells （<italic>P</italic><0.05） in a dose-dependent manner. Compared with the blank group， the co-administration group could significantly reduce MDR1， ABC semitransporter （ABCG2）， multidrug resistance associated protein （MRP1）， ERK， phosphorylated extracellular regulatory protein kinase （p-ERK）， Akt， phosphorylated protein kinase B （p-Akt）， mammals， rapamycin target protein （mTOR） and phosphorylated mammalian rapamycin target protein （p-mTOR） （<italic>P</italic><0.05）， with the same results in the doxorubicin group. Compared with the blank group， there was no significant difference in the distribution and fluorescence intensity of MDR1 on the cell membrane between the Adr group and the notoginseng total saponins （25 mg·L^-1） group. Compared with the blank group and the doxorubicin group， TNS could significantly reduce the distribution of MDR1 on the cell membrane （<italic>P</italic><0.05）. Conclusion:TNS can inhibit the ERK/Akt pathway， reduce the expression of MDR1， and significantly increase the accumulation of doxorubicin in HepG2/Adr cells， which may be one of the mechanisms of notoginseng total saponins in reversing resistance.

Shikonin Affects Uterine Leiomyoma in Rats by Regulating ERK Signaling Pathway / 中国实验方剂学杂志

Objective:To investigate the effect of shikonin on uterine leiomyoma in rats and its molecular mechanism. Method:Sixty female SD rats， of SPF grade and weighing 200-250 g， were randomly divided into the control group， model group， low-， medium-， and high-dose （5， 10， 20 mg·kg^-1） shikonin groups， and mifepristone group. A rat model of uterine leiomyoma was established， and the changes in uterine wet weight， uterine coefficient， and smooth muscle thickness were detected after drug administration for four successive weeks. The pathological changes in uterine tissue were observed by hematoxylin-eosin （HE） staining. The contents of estrogen receptor （ER） and progesterone receptor （PR） in serum and uterus were measured by enzyme-linked immunosorbent assay （ELISA）， and the protein expression levels of ER， PR， phosphorylated extracellular signal-regulated kinase （p-ERK）， and ERK in the uterine tissue were assayed by Western blot. Result:Compared with the control group， the model group exhibited significantly increased uterine wet weight， uterine coefficient， and smooth muscle thickness （<italic>P</italic><0.01）， uterus deformity， focal smooth muscle cell necrosis and hyperplasia， neutrophil infiltration. elevated serum and uterine ER and PR （<italic>P</italic><0.01）， and up-regulated p-ERK protein expression in the uterine tissue （<italic>P</italic><0.01）. Compared with the model group， shikonin at the middle and high doses and mifepristone significantly reduced the uterine wet weight， uterine coefficient， and smooth muscle thickness （<italic>P</italic><0.01）， relieved the pathological changes in uterus，and lowered serum and uterine ER and PR， and down-regulated the p-ERK protein expression in the uterine tissue （<italic>P</italic><0.05）. In addition， the uterine wet weight， smooth muscle thickness， serum ER， and uterine PR and p-ERK protein expression in the low-dose shikonin group were significantly lower than those in the model group （<italic>P</italic><0.05）. Conclusion:Shikonin produces the anti-uterine leiomyoma activity possibly by inhibiting the activation of ERK pathway.