Extracellular Regulated Protein Kinases Research Articles

Ethanol extract of Cyathulae Radix inhibits osteoclast differentiation and bone loss

Cyathulae Radix, a traditional Chinese medicine and a common vegetable, boasts a history spanning millennia. It enhances bone density, boosts metabolism, and effectively alleviates osteoporosis-induced pain. Despite its historical use, the molecular mechanisms behind Cyathulae Radix's impact on osteoporosis remain unexplored. In this study, we investigated the effects and mechanisms of Cyathulae Radix ethanol extract (CEE) in inhibiting osteoporosis and osteoclastogenesis. Eight-week-old female mice underwent ovariectomy and were treated with CEE for eight weeks. Micro-computed tomography (micro-CT) assessed histomorphometric parameters, bone tissue staining observed distal femur histomorphology, and three-point bending tests evaluated tibia mechanical properties. Enzyme-linked immunosorbent assay (ELISA) measured serum estradiol (E2), receptor activator for nuclear factor B ligand (RANKL), and osteoprotegerin (OPG) levels. Osteoclastogenesis-related markers were analyzed via Western blotting (WB) and quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, CEE effects on RANKL-induced osteoclast formation and bone resorption were investigated in vitro using tartrate-resistant acid phosphatase (TRAP) staining, qRT-PCR, and WB assay. Compared with the ovariectomy (OVX) group, CEE treatment enhanced trabecular bone density, maximal load-bearing capacity, and various histomorphometric parameters. Serum E2 and OPG levels significantly increased, while Receptor activator of nuclear factor-κB (RANK) decreased in the CEE group. CEE downregulated matrix metallopeptidase 9 (MMP-9), Cathepsin K (CTSK), and TRAP gene and protein expression. In bone marrow macrophages (BMMs), CEE reduced mature osteoclasts, bone resorption pit areas, and MMP-9, CTSK, and TRAP expression during osteoclast differentiation. Compared with DMSO treatment, CEE markedly inhibited RANK, TNF receptor associated factor 6 (TRAF6), Proto-oncogene c-Fos (c-Fos), Nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) expressions, and Extracellular regulated protein kinases (ERK), c-Jun N-terminal kinase (JNK), NF-kappa B-p65 (p65) phosphorylation in osteoclasts. In conclusion, CEE significantly inhibits OVX-induced osteoporosis and RANKL-induced osteoclastogenesis, potentially through modulating the Estrogen Receptor (ER)/RANK/NFATc1 signaling pathway.

Edgeworthia gardneri (Wall.) Meisn. Ethanolic Extract Attenuates Endothelial Activation and Alleviates Cardiac Ischemia-Reperfusion Injury.

Endothelial pro-inflammatory activation is pivotal in cardiac ischemia-reperfusion (I/R) injury pathophysiology. The dried flower bud of Edgeworthia gardneri (Wall.) Meisn. (EG) is a commonly utilized traditional Tibetan medicine. However, its role in regulating endothelium activation and cardiac I/R injury has not been investigated. Herein, we showed that the administration of EG ethanolic extract exhibited a potent therapeutic efficacy in ameliorating cardiac endothelial inflammation (p < 0.05) and thereby protecting against myocardial I/R injury in rats (p < 0.001). In line with the in vivo findings, the EG extract suppressed endothelial pro-inflammatory activation in vitro by downregulating the expression of pro-inflammatory mediators (p < 0.05) and diminishing monocytes' firm adhesion to endothelial cells (ECs) (p < 0.01). Mechanistically, we showed that EG extract inhibited the nuclear factor kappa-B (NF-κB), c-Jun N-terminal kinase (JNK), extracellular regulated protein kinase (ERK), and p38 mitogen-activated protein kinase (MAPK) signaling pathways to attenuate EC-mediated inflammation (p < 0.05). Collectively, for the first time, this study demonstrated the therapeutic potential of EG ethanolic extract in alleviating I/R-induced inflammation and the resulting cardiac injury through its inhibitory role in regulating endothelium activation.

An Inulin-Type Fructan CP-A from Codonopsis pilosula Alleviated 5-Fluorouracil-Induced Intestinal Mucositis via the ERK/MLCK/MLC2 Pathway and Regulation of Gut Microbiota.

Intestinal mucositis (IM) is a common adverse effect of chemotherapy, limiting its clinical application. Codonopsis pilosula-derived CP-A (an inulin-type fructan) is an edible Chinese medicine with anti-inflammatory and gastrointestinal protective effects, which may be useful for treating IM. Here, we explored CP-A's role in ameliorating IM induced by 5-fluorouracil (5-FU) and investigated the underlying mechanism using in vitro experiments and rat models. Western blotting, immunohistochemistry (IHC), and real-time PCR (RT-PCR) analyses were used to assess protein expression related to the extracellular-regulated protein kinases (ERK)/myosin light chain kinase (MLCK)/myosin light chain 2 (MLC2) signaling pathway and tight junction proteins. Inflammatory factors were quantified using enzyme-linked immunosorbent assays (ELISAs), and 16S rRNA amplicon sequencing was employed for cecum content analysis. The results indicated that CP-A restored body weight and food intake and reversed histopathological changes in IM rats. Further, abnormal MLCK activation induced by 5-FU was attenuated by CP-A via the ERK/MLCK/MLC2 pathway. CP-A treatment improved tight junction protein levels and reduced inflammatory factor expression. Moreover, CP-A intervention regulated the intestinal microbiota community structure, increasing the abundance of Lactobacillus and decreasing the abundance of Shigella. In conclusion, CP-A mitigates 5-FU-induced IM by inhibiting the ERK/MLCK/MLC2 pathway, reducing the expression of inflammatory factors, improving the intestinal mucosal barrier, and regulating the intestinal microbial community. This study highlights CP-A's therapeutic potential in IM treatment and provides insights for future research.

Effects of electroacupuncture on repairing neurological damage following ischemic stroke based on miR-381-mediated SDF-1/CXCR4 signaling pathway.

To investigate the effects of electroacupuncture (EA) on the miR-381, leucine-rich repeat C4 protein (LRRC4), and downstream stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) signaling pathway in rat model of ischemic stroke, and to explore the mechanism by which EA improves neurological damage following ischemic stroke. Among 50 SPF male SD rats, 10 rats were randomly selected into a sham surgery group, and the remaining rats were used to establish the middle cerebral artery occlusion (MCAO) model. The 30 successfully modeled rats were randomly divided into a model group, an EA group, and an agonist group, with 10 rats in each group. The rats in the EA group received EA at "Baihui" (GV 20) and "Dazhui" (GV 14), with disperse-dense wave, a frequency of 2 Hz/10 Hz, and a current intensity of 1 mA, 30 min per session, once daily for a total of 14 days. The rats in the agonist group received miR-381 agonist injections into the lateral ventricle, with 10 μL per injection, every 7 days for a total of 2 injections. After intervention, ZeaLonga neurobehavioral deficit score was observed in each group. HE staining was performed to observe the morphological changes in the ischemic brain tissue of rats in each group. ELISA was used to measure the levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and nerve growth factor (NGF) in serum. Western blot was employed to detect the protein expression of LRRC4, SDF-1, CXCR4, and extracellular regulated protein kinase 1 (ERK1) in the ischemic brain tissue. Real-time PCR was utilized to assess the expression of miR-381 and LRRC4, SDF-1, CXCR4, ERK1 mRNA in the ischemic brain tissue. After intervention, the brain tissue showed disordered cell arrangement, reduced quantity, and significant interstitial edema, with numerous vacuoles in the model group. The pathological changes mentioned above were alleviated in the brain tissue of rats in the EA group and the agonist group. Compared with the sham surgery group, the rats in the model group exhibited increased ZeaLonga neurobehavioral deficit scores, elevated levels of serum TNF-α and IL-6 (P<0.01), and decreased serum NGF level (P<0.01)；the protein expression of SDF-1, CXCR4 and ERK1 in ischemic brain tissue was reduced (P<0.01), while LRRC4 protein expression was increased (P<0.01)；the expression of miR-381, as well as SDF-1, CXCR4 and ERK1 mRNA in ischemic brain tissue was decreased (P<0.01), while LRRC4 mRNA expression was increased (P<0.01). Compared with the model group, the rats in the EA group and the agonist group showed decreased ZeaLonga neurobehavioral deficit scores and reduced levels of serum TNF-α and IL-6 (P<0.05, P<0.01), and increased serum NGF levels (P<0.05, P<0.01); the protein expression of SDF-1, CXCR4 and ERK1 in ischemic brain tissue was increased (P<0.01), while LRRC4 protein expression was decreased (P<0.01)；the expression of miR-381, as well as SDF-1, CXCR4 and ERK1 mRNA in ischemic brain tissue was increased (P<0.05, P<0.01), while LRRC4 mRNA expression was decreased (P<0.01). EA at "Baihui" (GV 20) and "Dazhui" (GV 14) may promote the repair of neurological damage following ischemic stroke by up-regulating miR-381 to selectively inhibit LRRC4 expression, thereby activating the SDF-1/CXCR4 signaling pathway.

Effects of carbamazepine on BDNF expression in trigeminal ganglia and serum in rats with trigeminal neuralgia.

Trigeminal neuralgia (TN) is a severe chronic neuropathic pain that mainly affects the distribution area of the trigeminal nerve with limited treating efficacy. There are numerous treatments for TN, but currently the main clinical approach is to suppress pain by carbamazepine (CBZ). Brain-derived neurotrophic factor (BDNF) is closely related to chronic pain. This study aims to determine the effects of CBZ treatment on BDNF expression in both the trigeminal ganglion (TG) and serum of TN via a chronic constriction injury of the infraorbital nerve (ION-CCI) rat model. The ION-CCI models were established in male Sprague-Dawley rats and were randomly divided into a sham group, a TN group, a TN+low-dose CBZ treatment group (TN+20 mg/kg CBZ group), a TN+medium-dose CBZ treatment group (TN+40 mg/kg CBZ group), and a TN+high-dose CBZ treatment group (TN+80 mg/kg CBZ group). The mechanical pain threshold in each group of rats was measured regularly before and after surgery. The expressions of BDNF and tyrosine kinase receptor B (TrkB) mRNA in TGs of rats in different groups were determined by real-time PCR, and the expression of BDNF protein on neurons in TGs was observed by immunofluorescence. Western Blotting was used to detect the protein expression of BDNF, TrkB, extracellular regulated protein kinases (ERK), and phospho-extracellular regulated protein kinases (p-ERK) in TGs of rats in different groups. The expression of BDNF in the serum of rats in different groups was detected by enzyme-linked immunosorbent assay (ELISA). The results of mechanical pain sensitivity showed that there was no significant difference in the mechanical pain threshold in the right facial sensory area of the experimental rats in each group before surgery (all P>0.05). From the 3rd day after operation, the mechanical pain threshold of rats in the TN group was significantly lower than that in the sham group (all P<0.01), and the mechanical pain threshold of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 CBZ mg/kg group was higher than that in the TN group (all P<0.05). The BDNF and TrkB mRNA and protein expressions in TGs of rats in the TN group were higher than those in the sham group (all P<0.05), and those in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than the TN group (all P<0.05). The p-ERK levels in TG of rats in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were significantly decreased compared with the TN group (all P<0.05). The BDNF and neuron-specific nuclear protein (NeuN) were mainly co-expressed in neuron of TGs in the TN group and they were significantly higher than those in the sham group (all P<0.05). The co-labeled expressions of BDNF and NeuN in TGs of the TN+ 80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). The results of ELISA showed that the level of BDNF in the serum of the TN group was significantly higher than that in the sham group (P<0.05). The levels of BDNF in the TN+80 mg/kg CBZ group, the TN+40 mg/kg CBZ group, and the TN+20 mg/kg CBZ group were lower than those in the TN group (all P<0.05). Spearman correlation analysis showed that the BDNF level in serum was negatively correlated with mechanical pain threshold (r=-0.650, P<0.01). CBZ treatment can inhibit the expression of BDNF and TrkB in the TGs of TN rats, reduce the level of BDNF in serum of TN rats and the phosphorylation of ERK signaling pathway, so as to inhibit TN. The serum level of BDNF can be considered as an indicator for the diagnosis and prognosis of TN.

Modified Sijunzi Granules Exhibit Hemostatic Effect by Activating Akt and Erk Signal Pathways via Regulating 5-HT and Its Receptors Levels.

To investigate the hemostatic effect of modified Sijunzi Granules (MSG) in primary immune thrombocytopenia (ITP) zebrafish model and explore the potential mechanism. AB strain wild type zebrafish were treated with simvastatin (6 µmol/L) for 24 h to establish the hemorrhage model (model control group). The zebrafish were treated with MSG at different doses (55.6, 167, and 500 µg/mL), respectively. The hemostatic effect was assessed by examining the intestinal bleeding and hemostatic rate. 5-Hydroxytryptamine (5-HT) content was determined using enzyme-linked immunosorbent assay (ELISA) assay. The expressions of 5-HT2aR, 5-HT2bR, and SERT genes were detected by quantitative real-time polymerase chain reaction(PCR). The protein expressions of protein kinase B (Akt), p-Akt, extracellular regulated protein kinases (Erk), and p-Erk were examined using Western blot analysis. The intestinal bleeding rate was 37%, 40%, and 80% in the 55.6, 167, and 500 µg/mL dose of MSG, respectively, in which 55.6 and 167 µg/mL MSG dose groups were associated with significantly decreased intestinal bleeding rate when compared with the model control group (70%, P<0.05). Significantly higher hemostatic rates were also observed in the 55.6 (54%) and 167 (52%) µg/mL MSG dose groups (P<0.05). MSG increased the 5-HT content and mRNA expression levels of 5-HT2aR, 5-HT2bR, and SERT (P<0.05). In addition, caspase3/7 activity was inhibited (P<0.05). Significant increase in p-Akt and p-Erk was also detected after treatment with MSG (P<0.05). MSG could reduce the incidence and severity of intestinal bleeding in zebrafish by activating MAPK/Erk and PI3K/Akt signal pathways through regulating the levels of 5-HT and its receptors, which may provide evidence for the treatment of ITP.

Effective constituents and protective effect of Mudan granules against Schwann cell injury

Ethnopharmacological relevanceDiabetic peripheral neuropathy (DPN) is the most common complication of diabetes. Mudan granules (MD) is a Chinese patent medicine for treating DPN, which is composed of nine Chinese medicinal herbs, including the radix of Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao or Astragalus membranaceus (Fisch.) Bge. (Huangqi in Chinese), rhizome of Corydalis yanhusuo W.T. Wang (Yanhusuo), radix and rhizome of Panax notoginseng (Burk.) F. H. Chen (Sanqi), radix of Paeonia lactiflora Pall. or Paeonia veitchii Lynch (Chishao), radix and rhizome of Salvia miltiorrhiza Bge. (Danshen), rhizome of Ligusticum chuanxiong Hort. (Chuanxiong), flowers of Carthamus tinctorius L. (Honghua), lignum of Caesalpinia sappan L. (Sumu), and caulis of Spatholobus suberectus Dunn (Jixueteng). MD was reported to have a protective effect on Schwann cell (SC) that is considered as an important therapeutic target of DPN. However, the constituents of MD have not been reported, and the effective constituents and protective pathways for MD against SC injury remain unclear. Aim of the studyThis study aimed to identify the constituents in MD, and to investigate the effective constituents and protective pathways of MD against high-glucose/lipid injury in SC. Materials and methodsThe chemical constituents of MD were identified using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Protective effect and effective constituents screening were performed in an in vitro SC injury model induced by high glucose and lipid levels. The protective pathways of MD and its effective constituents were investigated by western blotting assay of related proteins. ResultsA total of 136 constituents were identified in MD. MD downregulated the phosphorylation of extracellular-regulated protein kinases 1/2 (ERK1/2) and expression of cyclooxygenase-2 (COX-2) and upregulated the expression of sirtuin 2 (SIRT2). Seven effective constituents were screened out, including three from Sanqi [20(R)-ginsenoside Rh2, 20(S)-ginsenoside Rh2, and ginsenoside Rk3], one from Huangqi (astragaloside II), one from Danshen (danshensu), and two from Chuanxiong (chlorogenic and cryptochlorogenic acid). Six of the seven compounds, excluding danshensu, inhibited the phosphorylation of ERK1/2. Both astragaloside II and chlorogenic acid upregulated the expression of SIRT2, and cryptochlorogenic acid and danshensu downregulated the expression of COX-2. ConclusionsThe constituents of MD were firstly identified, and seven effective constituents were found. MD can protect SC against high-glucose and -lipid injury by downregulating ERK1/2 phosphorylation and COX-2 expression and upregulating SIRT2 expression. Seven effective constituents regulated the expression of these proteins. This study presented an important advance toward elucidating the chemical constituents, and the effective constituents and protective pathways of MD against high-glucose/lipid injury in SC, which is very helpful for investigating the action mechanism of MD on treating DPN, and could ultimately inform the development of effective quality control procedures for MD production.

A novel trypsin of Trichinella spiralis mediates larval invasion of gut epithelium via binding to PAR2 and activating ERK1/2 pathway.

Proteases secreted by Trichinella spiralis intestinal infective larvae (IIL) play an important role in larval invasion and pathogenesis. However, the mechanism through which proteases mediate larval invasion of intestinal epithelial cells (IECs) remains unclear. A novel T. spiralis trypsin (TsTryp) was identified in IIL excretory/secretory (ES) proteins. It was an early and highly expressed protease at IIL stage, and had the potential as an early diagnostic antigen. The aim of this study was to investigate the biological characteristics of this novel TsTryp, its role in larval invasion of gut epithelium, and the mechanisms involved. TsTryp with C-terminal domain was cloned and expressed in Escherichia coli BL21 (DE3), and the rTsTryp had the enzymatic activity of natural trypsin, but it could not directly degrade gut tight junctions (TJs) proteins. qPCR and western blotting showed that TsTryp was highly expressed at the invasive IIL stage. Immunofluorescence assay (IFA), ELISA and Far Western blotting revealed that rTsTryp specifically bound to IECs, and confocal microscopy showed that the binding of rTsTryp with IECs was mainly localized in the cytomembrane. Co-immunoprecipitation (Co-IP) confirmed that rTsTryp bound to protease activated receptors 2 (PAR2) in Caco-2 cells. rTsTryp binding to PAR2 resulted in decreased expression levels of ZO-1 and occludin and increased paracellular permeability in Caco-2 monolayers by activating the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. rTsTryp decreased TJs expression and increased epithelial permeability, which could be abrogated by the PAR2 antagonist AZ3451 and ERK1/2 inhibitor PD98059. rTsTryp facilitated larval invasion of IECs, and anti-rTsTryp antibodies inhibited invasion. Both inhibitors impeded larval invasion and alleviated intestinal inflammation in vitro and in vivo. TsTryp binding to PAR2 activated the ERK1/2 pathway, decreased the expression of gut TJs proteins, disrupted epithelial integrity and barrier function, and consequently mediated larval invasion of the gut mucosa. Therefore, rTsTryp could be regarded as a potential vaccine target for blocking T. spiralis invasion and infection.

Impact of Folic Acid on the Resistance of Non-small Cell Lung Cancer Cells to Osimertinib by Regulating Methylation of DUSP1

Drug resistance is the main cause of high mortality of lung cancer. This study was conducted to investigate the effect of folic acid (FA) on the resistance of non-small cell lung cancer (NSCLC) cells to Osimertinib (OSM) by regulating the methylation of dual specificity phosphatase 1 (DUSP1). The OSM resistant NSCLC cell line PC9R was establishd by gradually escalation of OSM concentration in PC9 cells. PC9R cells were randomly grouped into Control group, OSM group (5 μmol/L OSM), FA group (600 nmol/L FA), methylation inhibitor decitabine (DAC) group (10 μmol/L DAC), FA+OSM group (600 nmol/L FA+5 μmol/L OSM), and FA+OSM+DAC group (600 nmol/L FA+5 μmol/L OSM+10 μmol/L DAC). CCK-8 method was applied to detect cell proliferation ability. Scratch test was applied to test the ability of cell migration. Transwell assay was applied to detect cell invasion ability. Flow cytometry was applied to measure and analyze the apoptosis rate of cells in each group. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) method was applied to detect the expression level of DUSP1 mRNA in cells. Methylation specific PCR (MSP) was applied to detect the methylation status of the DUSP1 promoter region in each group. Western blot was applied to analyze the expression levels of DUSP1 protein and key proteins in the DUSP1 downstream mitogen-activated protein kinase (MAPK) signaling pathway in each group. Compared with the Control group, the cell OD450 values (48 h, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the OSM group were obviously decreased (P<0.05); the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of extracellular regulated protein kinases (ERK) were obviously increased (P<0.05); the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the DAC group were obviously increased (P<0.05); the apoptosis rate, the expression of p38 MAPK protein, the phosphorylation level of ERK, and the methylation level of DUSP1 were obviously reduced (P<0.05). Compared with the OSM group, the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the FA+OSM group were obviously decreased (P<0.05); the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of ERK were obviously increased (P<0.05). Compared with the FA+OSM group, the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the FA+OSM+DAC group were obviously increased; the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of ERK were obviously reduced (P<0.05). FA may inhibit DUSP1 expression by enhancing DUSP1 methylation, regulate downstream MAPK signal pathway, then promote apoptosis, inhibit cell invasion and metastasis, and ultimately reduce OSM resistance in NSCLC cells.

Simultaneous detection of dynamic calcium signaling and ERK activity in living cells.

Calcium (Ca2+) is a universal second messenger in eukaryotic cells, and extracellular regulated protein kinases (ERK) are the core component of the mitogen-activated protein kinase (MAPK) signaling cascade. Both are involved in numerous physiological and pathological processes, such as organogenesis, tumorigenesis, proliferation, migration and apoptosis. Over the past decade, it has been found that calcium signaling can regulate the ERK activity through multiple mechanisms, and conversely, ERK signaling transduction can also affect the triggering and intensity of calcium signaling. However, there are few reports on how to perform real-time synchronous detection of these two signals. Here we described a method for dynamically and synchronously recording calcium signals and ERK activity in living cells, utilizing stable expression of multiple genetically-encoded probes and multi-channel synchronous detection technology using confocal microscopy. The protocol can be useful to address the spatiotemporal encoding dynamic mechanism of calcium signaling and ERK activity in single or multiple cells, and to reveal the interaction and causal characteristics of these two signals.

The role of uterus mitochondrial function in high-fat diet-related adverse pregnancy outcomes and protection by resveratrol.

This study elucidates the mechanism of obesity-related adverse pregnancy outcomes and further investigates the effect of resveratrol on reproductive performance in a short- or long-term HFD-induced obese mouse model. Results show that maternal weight had a significant positive correlation with litter mortality in mice. A long-term HFD increased body weight and litter mortality with decreased expression of uterine cytochrome oxidase 4 (COX4), which was recovered by resveratrol in mice. Moreover, HFD decreased the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factors-1 (Nrf-1), and phosphorylated adenosine 5'-monophosphate (AMP)-activated protein kinase (p-AMPK) and increased the expression of phosphorylated extracellular regulated protein kinases (p-ERK) in the uterus. Resveratrol, a polyphenol that can directly bind to the ERK protein, suppressed the phosphorylation of ERK, increased the expression of p-AMPK, PGC-1α and Nrf-1, and decreased litter mortality in mice.

Polysaccharide from Polygala tenuifolia alleviates cognitive decline in Alzheimer's disease mice by alleviating Aβ damage and targeting the ERK pathway

Ethnopharmacological relevancePolygala tenuifolia is used in a variety of Chinese medicine prescriptions for the classic dementia treatment, and polysaccharide is an important active component in the herb. Aim of the studyThis study investigated the in vivo anti-Alzheimer's disease (AD) activity of the polysaccharide PTPS from Polygala tenuifolia using the senescence-accelerated mouse/prone8 (SAMP8) model and explored its molecular mechanism to lay the foundation for the development of polysaccharide-based anti-AD drugs. Materials and methodsThe Morris water maze test (MWM)was used to detect changes in the spatial cognitive ability of mice, and Nissl staining was applied to observe the state of neurons in the classic hippocampus. The levels of acetylcholine (ACh) and acetylcholinesterase (AChE) were measured by ELISA. Immunofluorescence was used to reflect β-amyloid (Aβ) levels in brain tissue. Apoptosis was evaluated by TdT-mediated dUTP Nick-End Labeling (TUNEL) method. The status of dendritic branches and spines was observed by Golgi staining. Meanwhile, the expression levels of recombinant human insulin-degrading enzyme (IDE), brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor B (TrkB), extracellular regulated protein kinases (ERK), and cAMP-response element binding protein (CREB) proteins were determined by Western blotting. ResultsPTPS improves spatial cognitive deficits in AD mice, reduces cellular damage in the CA3 region of the hippocampus, maintains the balance of the cholinergic system, and exerts an anti-AD effect in vivo. The molecular mechanism of its action may be related to the reduction of Aβ deposition as well as the activation of ERK pathway-related proteins with enhanced synaptic plasticity. ConclusionsPTPS is able to exert anti-AD activity in vivo by mitigating Aβ damage and targeting the ERK pathway.

Treatment of rheumatoid arthritis with dissymmetric fluorine and pyridyl-substituted 3,5-bis(aryl)-4-piperidone derivatives by inhibition of NF-κB and MAPK activation

Inhibition of inflammation-related NF-κB and MAPK activation could treat rheumatoid arthritis (RA). Previously, some fluorine-substituted 3,5-bis(aryl)-4-piperidone derivatives (BAPs) exhibited promising anti-inflammatory activity. Herein, interesting structural optimization was carried out and generated thirty-eight dissymmetric fluorine and pyridyl-substituted BAPs (4a-s and 5a-s). They were confirmed by NMR and HRMS. A preliminary structure–activity relationship was summarized and discovered 3,5-CF3 and 3-pyridyl-substituted 4k exhibited less toxicity and higher anti-inflammatory activity. Preliminary mechanistic studies revealed that 4k inhibited Lipopolysaccharide-induced nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) activation by suppressing LPS-induced phosphorylation levels of NF-κB/p65, NF-κB/IκBα, c-Jun N-terminal kinase (JNK), extracellular regulated protein kinases (ERK), and NF-κB/p38 in RAW264.7 cells. In vivo, 4k inhibited the development of inflammation and synovial proliferation in rat joint tissues, significantly decreasing paw swelling and arthritis index in adjuvant-induced arthritis rats. More importantly, 4k did not affect body weight and splenic index values. Overall, 4k showed optimistic anti-RA effects, which may be developed as a potential multifunctional agent for the clinical treatment of RA.

Effect of miR-200b Liposome Nanoparticles on Chemotherapy Resistance in Rats with Breast Cancer Through Induction of Epidermal Growth Factor Receptor/Extracellular Signal-Regulated Kinase Signal Pathway

This study assessed the effect of miR-200b liposome nanoparticles in restraining chemotherapy resistance in rats with breast cancer through induction of epidermal growth factor receptor enzyme-linked immunosorbent assay enzyme-linked immunosorbent assay (EGFR)/extracellular regulated protein kinases (ERK) signal pathway. 50 rats were divided into 4 sets, which included control set, empty carrier set, miR-200b set, and set of miR-200b packaged with liposome nanoparticles. The liposome nanoparticles were prepared and identified, and drug-resistant breast cancer cells were observed and identified. The growth inhibition ratio, miR-200b expression, drug-resistance, growth curve, drug resistance of cells, EGFR and ERK protein expressions were observed. miR-200b expression in the et of miR-200b packaged with liposome nanoparticles was highest, second in the miR-200b set and empty carrier set, and lowest in the control set. The IC50 value in the miR-200b packaged with liposome nanoparticles was highest. The absorbance in the set of miR-200b liposome nanoparticles was lowest. The immunofluorescence (IF) strength of miR-200b in the miR-200b liposome nanoparticles was highest. The EGFR and ERK protein expressions, and levels of pEGFR and p-ERK in the miR-200b liposome nanoparticles set was highest. In conclusion, chemotherapy resistance of breast cancer cells could be restrained by miR-200b liposome nanoparticles through restraining of the EGFR/ERK signal pathway.

Effects of trichlorobisphenol A on the expression of proteins and genes associated with puberty initiation in GT1-7 cells and the relevant molecular mechanism

This study evaluated the effects of Cl3BPA on kisspeptin-G-protein coupled receptor 54 (GPR54)/gonadotropin-releasing hormone (GnRH) (KGG) signals and analyzed the roles of estrogen receptor alpha (ERɑ) and G-protein coupled estrogen receptor 1 (GPER1) in regulating KGG signals. The results showed that Cl3BPA at 50 μM increased the levels of intracellular reactive oxygen species (ROS) and GnRH, upregulated the protein levels of kisspeptin and the expression of fshr, lhr and gnrh1 genes related to KGG in GT1-7 cells. In addition, 50 μM Cl3BPA significantly upregulated the phosphorylation of extracellular regulated protein kinases 1/2 (Erk1/2), the protein levels of GPER1 and the expression of the gper1 as well as the most target genes associated with mitogen-activated protein kinase (MAPK)/Erk1/2 pathways. Specific signal inhibitor experiments found that Cl3BPA activated KGG signals by activating the GPER1-mediated MAPK/Erk1/2 signaling pathway at the mRNA level. A docking test further confirmed the interactions between Cl3BPA and GPER1. The findings suggest that Cl3BPA might induce precocious puberty by increasing GnRH secretion together with KGG signaling upregulation, which is driven by GPER1-mediated signaling pathway. By comparison, ClxBPAs with fewer chlorine atoms had more obvious effects on the expression of proteins and partial genes related to KGG signals in GT1-7 cells.

Antioxidant, Anti-Inflammatory and Pro-Differentiative Effects of Chlorogenic Acid on M03-13 Human Oligodendrocyte-like Cells

Chlorogenic acid (CGA), a polyphenol found mainly in coffee and tea, exerts antioxidant, anti-inflammatory and anti-apoptotic effects at the gastrointestinal level. However, although CGA is known to cross the blood–brain barrier (BBB), its effects on the CNS are still unknown. Oligodendrocytes (OLs), the myelin-forming cells in the CNS, are the main target in demyelinating neuroinflammatory diseases such as multiple sclerosis (MS). We evaluated the antioxidant, anti-inflammatory and anti-apoptotic roles of CGA in M03-13, an immortalized human OL cell line. We found that CGA reduces intracellular superoxide ions, mitochondrial reactive oxygen species (ROS) and NADPH oxidases (NOXs) /dual oxidase 2 (DUOX2) protein levels. The stimulation of M03-13 cells with TNFα activates the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-kB) pathway, leading to an increase in superoxide ion, NOXs/DUOX2 and phosphorylated extracellular regulated protein kinase (pERK) levels. In addition, tumor necrosis factor alpha (TNF-α) stimulation induces caspase 8 activation and the cleavage of poly-ADP-ribose polymerase (PARP). All these TNFα-induced effects are reversed by CGA. Furthermore, CGA induces a blockade of proliferation, driving cells to differentiation, resulting in increased mRNA levels of myelin basic protein (MBP) and proteolipid protein (PLP), which are major markers of mature OLs. Overall, these data suggest that dietary supplementation with this polyphenol could play an important beneficial role in autoimmune neuroinflammatory diseases such as MS.

Phytic acid improves osteogenesis and inhibits the senescence of human bone marrow mesenchymal stem cells under high-glucose conditions via the ERK pathway

Hyperglycaemia causes impairment of osteogenic differentiation and accelerates stem cell senescence, resulting in weakened osteogenesis and disordered bone metabolism. Phytic acid (PA) is an antioxidant that is reportedly beneficial to bone homeostasis. The present study aims to clarify how PA affects the osteogenic capacity and cellular senescence of bone marrow mesenchymal stem cells (BMSCs) exposed to high-glucose environments, as well as the potential molecular mechanisms. Our results indicate that osteogenic differentiation in BMSCs cultivated in high-glucose conditions is enhanced by PA, as evidenced by increased alkaline phosphatase activity and staining, Alizarin Red S staining, osteogenic marker in in vitro studies, and increased osteogenesis in animal experiments. PA also prevented high-glucose-induced senescence of BMSCs, as evidenced by the repression of reactive oxygen species production, senescence-associated β-galactosidase staining, and P21 and P53 expression. Furthermore, it was found that PA rescued the high-glucose-inhibited expression of phosphorylated extracellular regulated protein kinases (p-ERK). The inhibition of ERK pathway by the specific inhibitor PD98059 blocked the PA-enhanced osteogenesis of BMSCs and promoted cell senescence. Our results revealed that PA enhances osteogenic differentiation and inhibits BMSC senescence in a high-glucose environment. In addition, the activation of the ERK pathway seems to mediate the beneficial effects of PA. The findings provide novel insights that could facilitate bone regeneration in patients with diabetes.

Molecular insights into the effects of tetrachlorobisphenol A on puberty initiation in Wistar rats

Tetrachlorobisphenol A (TCBPA) is the chlorinated derivative of bisphenol A (BPA). Several studies have found that BPA adversely affects the reproductive activity largely through binding to estrogen receptors and the critical period of BPA exposure advances the vaginal opening time in the female offspring via the kisspeptin/G protein-coupled receptor 54 (KGG) system. However, whether TCBPA can affect puberty initiation via KGG and the roles of estrogen receptors in this process remain unknown. Therefore, this study investigated the influence of TCBPA on the onset time of puberty in Wistar rats and the related molecular mechanisms by combing in vitro GT1–7 cells and molecular docking. In female Wistar rats, TCBPA at ≥100 mg/kg bw/day (49.2 μmol/L in rat body) markedly advanced vaginal opening time and increased serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and gonadotropin-releasing hormone (GnRH). It also increased the relative gene expression of LH receptor (LHR), GnRH1, and FSH receptor (FSHR) in hypothalamic-pituitary-gonadal (HPG) axis tissues. In GT1–7 cells, TCBPA increased genes and proteins associated with KGG pathway and activated the extracellular-regulated protein kinase 1/2 (Erk1/2) and phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) pathways via G protein-coupled estrogen membrane receptor 1 (GPER1) and estrogen receptor alpha (ERα). Docking analyses supported its interactions with GPER1 and ERα, and treatment with specific inhibitors of ERα- and GPER1-modulated PI3K/Akt and Erk1/2 signaling suppressed its effects. Taken together, TCBPA-induced advancement of puberty initiation in Wistar rats thus results primarily from increased LH, GnRH, and FSH secretion together with GnRH1, FSHR, and LHR upregulation driven by ERα- and GPER1-modulated Erk1/2 and PI3K/Akt signaling. Our results provide new molecular insights into the reproductive toxicity of EDCs.

In vitro protective effect of recombinant prominin-1 combined with microRNA-29b on N-methyl-D-aspartate-induced excitotoxicity in retinal ganglion cells.

To determine the in vitro protective effect of recombinant prominin-1 (Prominin-1)+microRNA-29b (P1M29) on N-methyl-D-aspartate (NMDA)-induced excitotoxicity in retinal ganglion cells (RGCs). RGC-5 cells were cultured, and NMDA-induced excitotoxicity at the range of 100-800 µmol/L was assessed using the MTT assay. NMDA (800 µmol/L) was selected as the appropriate concentration for preparing the cell model. To evaluate the protective effect of P1M29 on the cell model, Prominin-1 was added at the concentration of 1-6 ng/mL for 48h, and the cell survival was investigated with/without microRNA-29b. After obtaining the appropriate concentration and time of P1M29 at 48h, real-time polymerase chain reaction (PCR) was utilized to detect the relative mRNA expression of vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β2. Western blot detection was applied to measure the phosphorylation levels of protein kinase B (AKT) and extracellular regulated protein kinases (ERK) in RGC-5 cells after treatment with Prominin-1. Apoptosis study of the cell model was conducted by flow cytometry for estimating the anti-apoptotic effect of P1M29. Immunofluorescence analysis was used to analyze the expression levels of VEGF and TGF-β2. MTT cytotoxicity assays demonstrated that P1M29 group had significantly higher cell survival rate than Prominin-1 group (P<0.05). Real-time PCR data indicated that the expression levels of VEGF were significantly increased in both Prominin-1 and P1M29 groups compared NMDA and microRNA-29b group (P<0.05), while TGF-β2 were significantly decreased in both microRNA-29b and P1M29 groups compared NMDA and Prominin-1 group (P<0.05). Western blot results showed that both Prominin-1 and P1M29 groups significantly increased the phosphorylation levels of AKT and ERK compared to NMDA and microRNA-29b groups (P<0.05). Flow cytometry analysis revealed that P1M29 could prevent RGC-5 cell apoptosis in the early stage of apoptosis, while immunofluorescence results showed that P1M29 group had higher expression of VEGF and lower expression of TGF-β2 with a stronger green fluorescence than NMDA group. Prominin-1 combined with microRNA-29b can provide a suitable therapeutic option for ameliorating NMDA-induced excitotoxicity in RGC-5 cells.

Improvement Effect of Mitotherapy on the Cognitive Ability of Alzheimer's Disease through NAD+/SIRT1-Mediated Autophagy.

To date, Alzheimer's disease (AD) has grown to be a predominant health challenge that disturbs the elderly population. Studies have shown that mitochondrial dysfunction is one of the most significant features of AD. Transplantation therapy of healthy mitochondria (mitotherapy), as a novel therapeutic strategy to restore mitochondrial function, is proposed to treat the mitochondria-associated disease. Also, the molecular mechanism of mitotherapy remains unclear. Here, we applied the mitotherapy in AD model mice induced by amyloid-β (Aβ) plaque deposition and suggested that autophagy would be an important mechanism of the mitotherapy. After the healthy mitochondria entered the defective neuronal cells damaged by the misfolded Aβ protein, autophagy was activated through the NAD+-dependent deacetylase sirtuin 1 (SIRT1) signal. The damaged mitochondria and Aβ protein were eliminated by autophagy, which could also decrease the content of radical oxygen species (ROS). Moreover, the levels of brain-derived neurotrophic factor (BDNF) and extracellular-regulated protein kinases (ERK) phosphorylation increased after mitotherapy, which would be beneficial to repair neuronal function. As a result, the cognitive ability of AD animals was ameliorated in a water maze test after the healthy mitochondria were administrated to the mice. The study indicated that mitotherapy would be an effective approach to AD treatment through the mechanism of autophagy activation.