Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin (IL)-12 plays a pivotal role in the development of T helper type 1 (Th1)-immune response, which may have therapeutic effects on diseases associated with pathologic Th2 responses such as allergic disorders and asthma. In this study, we investigated the effects of berberine, a benzodioxoloquinolizine alkaloid with anti-microbial and anti-tumor activities, on the production of IL-12 p40, an inducible subunit of IL-12, in mouse macrophages. Berberine-induced IL-12 p40 production and activation of p38 mitogen-activated protein kinase (MAPK) in dose-dependent manners, which were significantly inhibited by p38 MAPK inhibitors and yohimbine, indicating that p38 MAPK and alpha(2)-adrenergic receptor were involved in the induction of IL-12 p40 production in mouse macrophages by berberine. Furthermore, berberine significantly enhanced IL-12 p40 production in mouse macrophages when combined with lipopolysaccharide, a well-known inducer of IL-12 production. These findings may explain some of the known biological effects of berberine and suggests berberine as an immunotherapeutic compound for induction of IL-12, which is potentially applicable for tumors, infectious disease, and airway inflammation.
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PMID:Involvement of p38 mitogen-activated protein kinase in the induction of interleukin-12 p40 production in mouse macrophages by berberine, a benzodioxoloquinolizine alkaloid. 1203 75

Coptisine, an isoquinoline alkaloid isolated from rhizome of Coptis japonica, inhibits proliferation of vascular smooth muscle cells (VSMCs). The aim of this study was to evaluate the action of coptisine, along with berberine (a structurally similar isoquinoline alkaloid), on progression of the cell cycle in VSMCs. Coptisine displayed antiproliferative action against VSMCs by blocking the cell cycle at G(1) and G(2)/M phases. The G(1) block was shown by inhibition of [(3)H]thymidine incorporation into VSMCs at coptisine concentrations higher than 15 microM. The mechanism underlying the G(1) arrest involved a decrease in cyclin D1 protein, although cyclin E, A, and B were not affected by coptisine treatment. The selective reduction in cyclin D1 protein was mainly attributable to accelerated proteolysis via proteasome-dependent pathway, since it was inhibited by a proteasome inhibitor, N-carbobenzoxy-L-leucinyl-L-leucinyl-L-norleucinal (MG132) and further the mRNA level of cyclin D1, protein synthesis, and mitogen-activated protein kinase (MAPK) activity remained unaltered. The mechanism underlying the G(2)/M arrest involved partial inhibition of tubulin polymerization, which was apparent at coptisine concentration of 3 microM. Berberine arrested the cell cycle at G(1) phase via a mechanism identical with coptisine, but did not cause block at G(2)/M phase. The results demonstrate that a small difference in the structure between isoquinoline alkaloids produces a big difference in activity, and that coptisine has a unique double action in arresting the cell cycle of VSMCs.
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PMID:Double blockade of cell cycle progression by coptisine in vascular smooth muscle cells. 1614 Feb 75

Lysophosphatidylcholine (lysoPC) induces vascular smooth muscle cell (VSMC) proliferation and migration, which has been proposed to initiate the intimal thickening in coronary atherosclerotic lesions. Berberine is an alkaloid in Berberis aquifolium and many other plants. Recently, it has been shown to have beneficial effects on the cardiovascular system, such as anti-hyperglycemic and cholesterol-lowering activity. In this study, we investigated its effects on lysoPC-induced VSMC proliferation and migration. Berberine inhibited lysoPC-induced DNA synthesis and cell proliferation in VSMCs, as well as migration of the lysoPC-stimulated VSMCs. It also inhibited the activation of extracellular signal-regulated kinases (ERKs) and reduced transcription factor AP-1 activity and the lysoPC-induced increases in intracellular reactive oxygen species (ROS). These results indicate that the inhibitory effects of berberine on lysoPC-stimulated VSMC proliferation and migration are attributable to inhibition of ROS generation and hence of activation of the ERK1/2 pathway. This suggests that berberine has potential in the prevention of atherosclerosis and restenosis.
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PMID:Berberine inhibits the production of lysophosphatidylcholine-induced reactive oxygen species and the ERK1/2 pathway in vascular smooth muscle cells. 1640 60

Vascular smooth muscle cell (SMC) proliferation plays an important role in the pathogenesis of atherosclerosis and post-angioplasty restenosis. Berberine is a well-known component of the Chinese herb medicine Huanglian (Coptis chinensis), and is capable of inhibiting SMC contraction and proliferation, yet the exact mechanism is unknown. We therefore investigated the effect of berberine on SMC growth after mechanic injury in vitro. DNA synthesis and cell proliferation assay were performed to show that berberine inhibited serum-stimulated rat aortic SMC growth in a concentration-dependent manner. Mechanical injury with sterile pipette tip stimulated the regrowth of SMCs. Treatment with berberine prevented the regrowth and migration of SMCs into the denuded trauma zone. Western blot analysis showed that activation of the MEK1/2 (mitogen-activated protein kinase kinase 1/2), extracellular signal-regulated kinase (ERK), and up-regulation of early growth response gene (Egr-1), c-Fos and Cyclin D1 were observed sequentially after mechanic injury in vitro. Semi-quantitative reverse-transcription PCR assay further confirmed the increase of Egr-1, c-Fos, platelet-derived growth factor (PDGF) and Cyclin D1 expression in a transcriptional level. However, berberine significantly attenuated MEK/ERK activation and downstream target (Egr-1, c-Fos, Cyclin D1 and PDGF-A) expression after mechanic injury in vitro. Our study showed that berberine blocked injury-induced SMC regrowth by inactivation of ERK/Egr-1 signaling pathway thereby preventing early signaling induced by injury in vitro. The anti-proliferative properties of berberine may be useful in treating disorders due to inappropriate SMC growth.
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PMID:Berberine suppresses MEK/ERK-dependent Egr-1 signaling pathway and inhibits vascular smooth muscle cell regrowth after in vitro mechanical injury. 1644 24

Berberine is a plant alkaloid used in traditional Chinese medicine and has been reported to have antihyperglycemic activity in NIDDM patients. However, the molecular basis for this action is yet to be elucidated. Here we investigate the effects and signaling pathways of berberine on L6 rat skeletal muscles. Our study demonstrates that berberine stimulates glucose uptake in a time- and dose-dependent manner. Intriguingly, berberine-stimulated glucose uptake does not vary as insulin concentration increases, and could not be blocked by the PI 3-kinase inhibitor wortmannin. Berberine only weakly stimulates the phosphorylation of Akt/PKB, a key molecule in the insulin signaling pathway, but strongly promotes the phosphorylation of AMPK and p38 MAPK. The effects of berberine are not a result of pro-oxidant action, but a consequence of an increased cellular AMP:ATP ratio. Moreover, berberine-stimulated glucose uptake is inhibited by the AMPK inhibitor Compound C and the p38 MAPK inhibitor SB202190. Inhibition of AMPK reduces p38 MAPK phosphorylation, suggesting that AMPK lies upstream of p38 MAPK. These results suggest that berberine circumvents insulin signaling pathways and stimulates glucose uptake through the AMP-AMPK-p38 MAPK pathway, which may account for the antihyperglycemic effects of this drug.
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PMID:Berberine-stimulated glucose uptake in L6 myotubes involves both AMPK and p38 MAPK. 1704 64

Berberine exerts a hypoglycemic effect, but the mechanism remains unknown. In the present study, the effect of berberine on glucose uptake was characterized in 3T3-L1 adipocytes. It was revealed that berberine stimulated glucose uptake in 3T3-L1 adipocytes in a dose- and time-dependent manner with the maximal effect at 12 hours. Glucose uptake was increased by berberine in 3T3-L1 preadipocytes as well. Berberine-stimulated glucose uptake was additive to that of insulin in 3T3-L1 adipocytes, even at the maximal effective concentrations of both components. Unlike insulin, the effect of berberine on glucose uptake was insensitive to wortmannin, an inhibitor of phosphatidylinositol 3-kinase, and SB203580, an inhibitor of p38 mitogen-activated protein kinase. Berberine activated extracellular signal-regulated kinase (ERK) 1/2, but PD98059, an ERK kinase inhibitor, only decreased berberine-stimulated glucose uptake by 32%. Berberine did not induce Ser473 phosphorylation of Akt nor enhance insulin-induced phosphorylation of Akt. Meanwhile, the expression and cellular localization of glucose transporter 4 (GLUT4) were not altered by berberine. Berberine did not increase GLUT1 gene expression. However, genistein, a tyrosine kinase inhibitor, completely blocked berberine-stimulated glucose uptake in 3T3-L1 adipocytes and preadipocytes, suggesting that berberine may induce glucose transport via increasing GLUT1 activity. In addition, berberine increased adenosine monophosphate-activated protein kinase and acetyl-coenzyme A carboxylase phosphorylation. These findings suggest that berberine increases glucose uptake through a mechanism distinct from insulin, and activated adenosine monophosphate-activated protein kinase seems to be involved in the metabolic effect of berberine.
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PMID:Berberine stimulates glucose transport through a mechanism distinct from insulin. 1729 31

Berberine is the major constituent of Coptidis Rhizoma with multiple pharmacological activities, including anti-inflammation, promotion of apoptosis and anticancer potential effect. Mitogen-activated protein kinase (MAPK) and reactive oxygen species (ROS) may contribute to the causal relationship between tumorigenesis and pro-apoptotic function. Berberine is studied for the mechanism of its action in apoptotic pathway in human colonic carcinoma cell. Treatment of SW620 cells with 50 microM berberine resulted in activation of the caspase 3 and caspase 8, cleavage of poly ADP-ribose polymerase (PARP) and the release of cytochrome c; whereas, the expression of BID and anti-apoptosis factor c-IAP1, Bcl-2, and Bcl-(XL) were decreased markedly. Berberine-induced, dose-dependent induction of apoptosis was accompanied by sustained phosphorylation of JNK and p38 MAPK, as well as generation of the ROS. Furthermore, the induction of apoptosis was alleviated by inhibitors specific for JNK and p38. In addition, there was an increase in the cellular levels of phospho-c-Jun, FasL and t-BID in the berberine-induced apoptosis via the activation of JNK and p38 signaling modules. NAC administration, a scavenger of ROS, reversed berberine-induced apoptosis effects via inhibition of JNK, p38 and c-jun activation, and FasL and t-BID expression. These results leads us to speculate that berberine may play an apoptotic cascade in SW620 cells by activation of the JNK/p38 pathway and induction of ROS production, providing a new mechanism for berberine-induced cell death in human colon cancer cells.
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PMID:Berberine induces apoptosis in SW620 human colonic carcinoma cells through generation of reactive oxygen species and activation of JNK/p38 MAPK and FasL. 1767 78

Berberine, an herbal alkaloid, has been reported to have a lipid lowering effect by stabilizing hepatic LDLR mRNA in an ERK-dependent manner rather than promoting transcriptional activity. However, considering the complexity of interconnected signal pathways in biological processes, it is highly possible that there exist signal pathway(s) other than ERK pathway which contribute to the berberine-induced up-regulation of LDLR. In the present study, we examined possible involvement of other signal pathways in berberine-induced hepatic LDLR up-regulation. As evidenced by RT-PCR, berberine-induced LDLR mRNA expression was inhibited by JNK inhibitor SP600125 pretreatment. Furthermore, we demonstrate that putative c-jun binding site of LDLR promoter is important in berberine-induced LDLR transcription using luciferase assay. The result of EMSA also shows that berberine induces c-jun binding to LDLR promoter and this is decreased by SP600125 pretreatment. The present study demonstrates that berberine increases transcriptional activity of LDLR promoter and this involves JNK pathway.
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PMID:Berberine-induced LDLR up-regulation involves JNK pathway. 1776 19

Berberine (BBR) has been implicated in bone biology. Although BBR reduces osteoporosis by enhancing BMD and inhibiting osteoclast activity, the effects of BBR on osteoblasts during the process of osteogenesis have not been thoroughly studied. In osteoblastic cells, BBR enhanced the expression of osteogenic marker genes including osteopontin and osteocalcin and promoted the transcriptional activity of the key osteogenic transcription factor Runx2. In osteoblasts, BBR increased the binding of Runx2 to the promoter region of osteopontin. The recruitment of co-factors such as p300 and HDAC1 to the promoter regions of osteopontin and osteocalcin was regulated by BBR, resulting in an enhancement in the expression of those genes. Furthermore, BBR activated p38 mitogen-activated protein kinase (MAPK) and increased cyclooxygenase 2 (COX2) expression, which are key factors in osteoblast differentiation. Consistently, a p38 MAPK-specific inhibitor attenuated the effect of BBR on osteogenesis, whereas p38 MAPK overexpression augmented BBR-induced osteogenic gene expression. Moreover, BBR stimulated bone area formation in calvarial organ culture. Taken together, these findings indicate that BBR promotes osteoblast differentiation through activation of Runx2 by p38 MAPK. Therefore, BBR may be a potential therapeutic agent to treat bone-related disorders including osteoporosis.
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PMID:Berberine promotes osteoblast differentiation by Runx2 activation with p38 MAPK. 1841 Feb 24

Berberine (BBR) has been shown to improve several metabolic disorders, such as obesity, type 2 diabetes, and dyslipidemia, by stimulating AMP-activated protein kinase (AMPK). However, the effects of BBR on proinflammatory responses in macrophages are poorly understood. Here we show that BBR represses proinflammatory responses through AMPK activation in macrophages. In adipose tissue of obese db/db mice, BBR treatment significantly downregulated the expression of proinflammatory genes such as TNF-alpha, IL-1beta, IL-6, monocyte chemoattractant protein-1 (MCP-1), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Consistently, BBR inhibited LPS-induced expression of proinflammatory genes including IL-1beta, IL-6, iNOS, MCP-1, COX-2, and matrix metalloprotease-9 in peritoneal macrophages and RAW 264.7 cells. Upon various proinflammatory signals including LPS, free fatty acids, and hydrogen peroxide, BBR suppressed the phosphorylation of MAPKs, such as p38, ERK, and JNK, and the level of reactive oxygen species in macrophages. Moreover, these inhibitory effects of BBR on proinflammatory responses were abolished by AMPK inhibition via either compound C, an AMPK inhibitor, or dominant-negative AMPK, implying that BBR would downregulate proinflammatory responses in macrophages via AMPK stimulation.
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PMID:Berberine suppresses proinflammatory responses through AMPK activation in macrophages. 1920 54


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