BACKGROUNDMesangial hypercellularity is a critical early histopathological finding in human and experimental glomerular diseases. Hyperlipidemia and the glomerular deposition of lipoproteins are commonly associated with mesangial hypercellularity and play an important pathobiological role in the development of glomerular diseases. The activated cytoplasmic mitogen-activated protein kinase (MAPK), including mainly extracellular-signal regulated protein kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38, has been thought to translocate into the nucleus and activate various transcription factors and protooncogenes associated with cell growth and proliferation. Lipoprotein (a) (Lp(a)) has been shown to stimulate proliferation of mesangial cells, but the events of Lp(a) signaling have not yet been characterized. The purpose of this study was to investigate the signal transduction pathways involved in Lp(a)-induced cell proliferation and provide an evidence for the participation of Lp(a) in intracellular signaling pathways for mesangial cell proliferation.

METHODSLp(a) was isolated from a patient who was being treated with low density lipoprotein (LDL)-apheresis by density gradient ultracentrifugation and then chromatography. Human mesangial cells (HMCs) were isolated by the sequential sieving technique and stimulated with Lp(a) in different concentration and time course. The DNA synthesis of the cells was measured by [3H] thymidine incorporation for detecting the proliferation. The expression of all the three members of MAPK family, including ERK1/ERK2, JNK, and p38, and their phosphorylation were detected by Western blotting.

RESULTSLp(a) could induce a significant dose-dependent proliferation of HMCs. The 3H-TdR incorporation was 1.64+/-0.31, 1.69+/-0.48, 3.59+/-0.68 (P<0.01), 4.14+/-0.78 (P<0.01), and 4.05+/-0.55 (P<0.01) (10(3) cpm) at the Lp(a) concentration of 0, 5, 10, 25, and 50 microg/ml, respectively. Lp(a) induced an increase in ERK1/ERK2 phosphorylation between 5 and 60 minutes, and in JNK phosphorylation between 15 and 30 minutes after incubating with HMCs, whereas the level of p38 and its phosphorylation was not changed.

CONCLUSIONSLp(a) could stimulate the proliferation of HMCs by activiating the phosphorylation of ERK1/ERK2 and JNK MAPK signaling pathway, whereas p38 pathway had no effect on the Lp(a)-induced HMC proliferation, which indicated that three MAPKs seem to be distinctly involved in the effect. In particular, it also provides the evidence that Lp(a) may act as one of the major endogenous modulators for mitogenic signaling response and cell proliferation within the glomerulus.

Blotting, Western ; Cells, Cultured ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Lipoprotein(a) ; pharmacology ; Mesangial Cells ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Phosphorylation ; drug effects ; p38 Mitogen-Activated Protein Kinases ; metabolism

: To assess the () recombinant gingivalis gingipain R2 (rRgpB)-induced Ca mobilization in human gingival fibroblast (HGF) mediated by protease-activated receptor (PAR) and its downstream signal transduction pathways. : Flow cytometry was used to detect the expression of PAR in HGF. The proliferation of HGF was measured by CCK-8. The dynamic changes of intracellular Ca concentration in HGF induced by rRgpB and the blocking effect of PAR-1 antagonist were observed by laser confocal microscopy. Western blot was performed to determine the phosphorylation levels of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) 1/2, p38 mitogen-activated protein kinase (p38 MAPK) and p65 in HGF. : PAR-1 and PAR-3 were expressed in HGF, and the rRgpB could promote the proliferation of HGF. rRgpB caused a transient increase in [Ca], which could be completely suppressed by vorapaxar, a PAR-1 antagonist. The phosphorylation levels of JNK, ERK1/2 and p65 were significantly up-regulated after the induction of rRgpB for and (all <0.05), which was completely inhibited by vorapaxar. However, the phosphorylation level of p38 MAPK had no significant change after rRgpB stimulation. : rRgpB causes an increase in [Ca] in HGF mediated by PAR-1. JNK, ERK1/2 and nuclear factor-κB may be involved in intracellular signal transduction after PAR-1 activation.
Fibroblasts ; Humans ; JNK Mitogen-Activated Protein Kinases/metabolism* ; MAP Kinase Signaling System ; Phosphorylation ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases/metabolism*

OBJECTIVETo investigate the intracellular distribution and the activation of mitogen-activated protein kinases (MAPKs) in myocardial cells in scalded rats.

METHODSWistar rats were used in this study and forty of them were inflicted with 40% III degree scald on the back and eight normal ones as control. The samples of plasma and myocardial tissue were harvested at 1, 3, 6, 12 and 24 postburn hours (PBHs), and samples were also obtained from normal rats as control. The plasma CK-MB activity was determined by routine method. The activation states of all the members of MAPKs [p38 kinase, ERKs (extracellular signal-regulated protein kinases) and JNK (c-Jun N-terminal kinase)] in the myocardial tissue samples were detected by Western blotting. The tissue slides were stained by immunohistochemistry methods.

RESULTSActivation of p38 kinase and ERK with nuclear translocation was found postburn, especially during 1, 3 and 6 PBHs (P < 0.01). But there was no activation of JNK during 1 - 24 PBHs. The plasma CK-MB content increased at 3 PBH and reached summit at 12 PBHs (P < 0.05 - 0.01).

CONCLUSIONp38 kinase and ERK signal pathways might play important roles in the early postburn injury of myocardial cells, inducing myocardial injury.

Animals ; Burns ; metabolism ; Female ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Male ; Mitogen-Activated Protein Kinases ; metabolism ; Myocytes, Cardiac ; metabolism ; pathology ; Rats ; Rats, Wistar ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo detect protein expression of ERK(1), ERK(2), JNK(1), p38 and MEK(1), MEK(2) in human hepatocellular carcinoma and adjacent non-neoplastic liver.

METHODSIn 16 surgically resected hepatocellular carcinoma and para-carcinoma tissues, Western blotting was used to detect expression of ERK(1), ERK(2), JNK(1), p38 and MEK(1), MEK(2).

RESULTSIn all cases, ERK(1), ERK(2), p38 expression in hepatocellular carcinoma was significantly higher than that in para-carcinoma: integral optic density (IOD) of ERK(1) was 300 +/- 98 in carcinoma and 98 +/- 48 in para-carcinoma tissues (t = 2.519, P < 0.01); IOD of ERK(2) was 587 +/- 83 in carcinoma and 232 +/- 96 in para-carcinoma tissues (t = 2.745, P < 0.01); IOD of p38 was 270 +/- 85 in carcinoma and 107 +/- 88 in para-carcinoma tissues (t = 2.491, P < 0.01). JNK(1) expression in hepatocellular carcinoma was significantly lower than that in para-carcinoma; IOD of JNK(1) was 111 +/- 93 in carcinoma and 292 +/- 109 in para-carcinoma tissues (t = 2.473, P < 0.01). Protein levels of MEK(1) and MEK(2) in carcinoma were significantly higher than in para-carcinoma. IOD of MEK(1) was 1 418 +/- 244 in carcinoma and 806 +/- 90 in para-carcinoma tissues (t = 2.546, P < 0.01). IOD of MEK(2) was 1 041 +/- 122 in carcinoma and 468 +/- 40 in para-carcinoma tissues (t = 2.861, P < 0.01).

CONCLUSIONSERK(1), ERK(2), MEK(1) and MEK(2) in the signal transduction pathway for cell proliferation are significantly overexpressed and the expression of JNK(1) is lower in hepatocellular carcinoma. Their unbalance is one of the important reasons for the over growth and infinite proliferation of the hepatocellular carcinoma cell. The p38 and JNK(1) may be activated by different pathway.

Adult ; Aged ; Carcinoma, Hepatocellular ; enzymology ; Enzyme Activation ; Female ; Humans ; JNK Mitogen-Activated Protein Kinases ; Liver Neoplasms ; enzymology ; MAP Kinase Kinase 1 ; Male ; Middle Aged ; Mitogen-Activated Protein Kinase Kinases ; analysis ; Mitogen-Activated Protein Kinases ; metabolism ; Protein-Serine-Threonine Kinases ; analysis

The MAPK signaling pathway plays a key role in the differentiation, proliferation and apoptosis of cells, and its family members mainly include extracellular signal-regulated kinase (ERK), stress-activated protein kinase (JNK), and p38 mitogen-activated protein kinase (p38MAPK). Recent studies have shown that the ERK, JNK and p38MAPK signaling pathways are closely associated with the development and progression of erectile dysfunction (ED). This review focuses on the correlation between the MAPK signaling pathway and ED.
Apoptosis ; Cell Differentiation ; Cell Proliferation ; Erectile Dysfunction ; etiology ; metabolism ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; MAP Kinase Signaling System ; Male ; Mitogen-Activated Protein Kinases ; metabolism ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases ; metabolism

The cell counting kit-8 (CCK-8) proliferation assay and diameter measure of neurospheres were used to investigate the effect of high-mobility group box 1 (HMGB1) on proliferation of primary rat neural stem cells (NSCs) in vitro, and c-Jun N-terminal protein kinase (JNK) potent inhibitor SP600125 was used to study the mechanism. The results demonstrated that HMGB1 significantly increased CCK-8 absorbance values and neurosphere diameters at concentrations of 1 and 10 ng/mL at 48 h and 72 h (P < 0.05), and the other HMGB1 concentration groups (0.01, 0.1, 100 ng/mL) showed no significant difference, compared with control group (P > 0.05). HMGB1 at 10 ng/mL significantly increased the NSCs proliferation accompanied by the rising of phosphorylated JNK levels (P < 0.01), and 10 μmol/L SP600125 prevented these effects in HMGB1-cultured NSCs (P < 0.01). In conclusion, low concentration of HMGB1 (1-10 ng/mL) can increase NSCs proliferation, which may play a role by promoting JNK phosphorylation.
Animals ; Cell Proliferation ; Cells, Cultured ; HMGB1 Protein ; pharmacology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Neural Stem Cells ; cytology ; Phosphorylation ; Rats

This study was purposed to explore the effect of hyperactivation of c-Jun NH(2)-terminal protein kinase (JNK) on the proliferation of B lymphoma cells. The human B lymphoma cell lines Daudi and Raji were chosen as research objects. The expression of JNK protein was determined by Western blot. The subcellular localization of JNK protein was detected by immunofluorescence. The cell cycle was analyzed by flow cytometry. The suppressive effect of JNK inhibitor SP600125 on the proliferation of Daudi and Raji cells was assayed by ATPLite method. The results demonstrated that hyperactivation of JNK has been found in Daudi and Raji cells. Immunofluorescence confirmed the aberrant subcellular localization of JNK protein in Daudi and Raji cells. Cell cycle assay revealed that Daudi and Raji cells underwent G(2)-M arrest in the presence of SP600125. Furthermore, Daudi and Raji cells showed significant increase in sub-G(1) population, an indicator of apoptotic cells, with the treatment of JNK inhibitors. These data suggested that JNK inhibitors suppressed the growth of B lymphoma cells via cell cycle arrest and apoptosis. Daudi and Raji cells treated with different concentrations of JNK selective inhibitor SP600125 showed dose-dependent reduction in the growth of Daudi and Raji cells. It is concluded that hyperactivation of JNK enhance the proliferation of Daudi and Raji cells. The aberrant subcellular localization of JNK protein may facilitate the nuclear accumulation of basal JNK activity, which made JNK to be a potential target to treat human B lymphoma.
Cell Line, Tumor ; Cell Proliferation ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Lymphoma, B-Cell ; metabolism ; pathology

OBJECTIVE: To investigate the mechanism of intense noise-induced cochlea cells death in guinea pig, and the effect of JNK signal transduction pathway in the procedure of cochlea cells apoptosis by intense noise-induced. METHOD: Thirty-two guinea pigs were randomly divided into 4 groups. The guinea pigs in the experiment groups were exposed to 4 kHz narrow band noise at 120 dB SPL for 4 h. After the noise expose for 1, 4, 14 days of the experiment guinea pigs, ABR of the guinea pigs on experiment and control groups were tested before put them to death. Four guinea pig's cochleas of every group were taken to paraffin section, and the rest was extracted the total cochlear's protein. Apoptosis was tested by terminal deoxynucleotidyl Transferase (TdT)-mediated deoxyuridine triphosphate (d-UTP) nick and labeling method (TUNEL). The phosphorylation of JNK and c-Jun were tested by immunohistochemistry and western blot methods. RESULT: Tunel-Positive cells in the Corti's, SGC and SV of experiment groups, and there have significant differences compared with the control group (P<0.01) and Tunel-Positive cells are most in 1 d experiment group. The positive cells of P-JNK and P-c-Jun could be detected in guinea pig's cochleas after noise exposed, but no positive cells were found in the control. Protein levels of P-JNK and P-c-Jun were risen up and activated quickly after noise exposed, and achieved peak in 1 d, 4 d and then fallen-offs, but still maintained higher levels within 14 d. CONCLUSION Intense noise causes cochlea cell lesion by inducing apoptosis to result in and JNK signal transduction pathway plays an important role in the procedure of apoptosis.
Animals ; Apoptosis ; Cochlea ; metabolism ; pathology ; Guinea Pigs ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Male ; Noise ; adverse effects ; Signal Transduction

Objective: To investigate the effect and underlying mechanism of paeoniflorin on hippocampal neuron apoptosis induced by lead acetate. Methods: In September 2020, primary hippocampal neuronal cells were isolated and cultured from fetal rats, and identified using cellular immunofluorescent. MTT assay was used to measure the cell viability to determine the concentration and time of lead acetate-induced hippocampal neuron apoptosis. MTT was also used to evaluate the effect of paeoniflorin concentration on the apoptosis of hippocampal neurons induced by lead acetate. According to the results, different concentrations of paeoniflorin were selected to intervene hippocampal neuron cells, after 24 h, lead acetate was added to the cells, meanwhile, blank and model groups were set up, the content of reactive oxygen species (ROS) , superoxide dismutase (SOD) , lactate dehydrogenase (LDH) , malondialdehyde (MDA) and Caspase-3 were measured. Extracellular signal regulated kinase (ERK) , phosphorylated ERK (p-ERK) , p38 mitogen -activated protein kinases (p38MAPK) , phosphorylated p38MAPK (p-p38MAPK) , c-Jun N-terminal kinase (JNK) and phosphorylated JNK (p-JNK) protein expression in hippocampal neuronal cells were determined by Western blotting. Results: The isolated and cultured hippocampal neurons were identified by immunofluorescence chemical staining and then treated with lead acetate, MTT results showed that lead acetate had the best toxicity effect when treated for 24 h at a concentration of 25 μmol/L. Paeoniflorin showed no cytotoxic effect on hippocampal neuronal cells when the concentrations below 80 μmol/L. Compared with the model group, the activity of hippocampal neuronal cells was significantly increased after treating with 20, 40 or 80 μmol/L paeoniflorin (P<0.05) . Compared with the blank group, the ROS activity, LDH release level, MDA content and caspase-3 content were significantly increased (P<0.01) , and the SOD activity was significantly decreased (P< 0.01) in the hippocampal neuronal cells of the model group. Compared with the model group, the ROS activity, LDH release level, MDA content and caspase-3 content were obviously decreased (P<0.05) , SOD activity was significantly increased (P <0.01) after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin. Relative to the model group, the ratio of p-ERK/ERK were significantly up-regulated (P<0.01) , while the ratios of p-p38MAPK/p38MAPK and p-JNK/JNK were significantly down-regulated after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin (P<0.05) . Conclusion: Paeoniflorin may down-regulate the expression of p-p38MAPK and p-JNK protein, up-regulate the expression of p-ERK protein, and inhibit the apoptosis of hippocampal neurons induced by lead acetate through the MAPK signaling pathway.
Acetates/pharmacology* ; Animals ; Apoptosis ; Caspase 3/metabolism* ; Extracellular Signal-Regulated MAP Kinases/metabolism* ; Glucosides ; Hippocampus/metabolism* ; JNK Mitogen-Activated Protein Kinases/pharmacology* ; Lead ; Monoterpenes ; Neurons/metabolism* ; Rats ; Reactive Oxygen Species/metabolism* ; Superoxide Dismutase/metabolism* ; p38 Mitogen-Activated Protein Kinases/metabolism*

Mitogen-activated protein (MAP) kinases comprise a family of protein-serine/threonine kinases, which are highly conserved in protein structures from unicellular eukaryotic organisms to multicellular organisms, including mammals. These kinases, including ERKs, JNKs and p38s, are regulated by a phosphorelay cascade, with a prototype of three protein kinases that sequentially phosphorylate one another. MAPKs transduce extracellular signals into a variety of cellular processes, such as cell proliferation, survival, death, and differentiation. Consistent with their essential cellular functions, MAPKs have been shown to play critical roles in embryonic development, adult tissue homeostasis and various pathologies. In this review, we discuss recent findings that reveal the profound impact of these pathways on chronic inflammation and, particularly, inflammation-associated cancer development.
Animals ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Humans ; Inflammation ; complications ; enzymology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; MAP Kinase Signaling System ; Mice ; Neoplasms ; enzymology ; etiology ; p38 Mitogen-Activated Protein Kinases ; metabolism