BACKGROUND: Epidemiological studies have suggested that noise exposure may increase the risk of type 2 diabetes mellitus (T2DM), and experimental studies have demonstrated that noise exposure can induce insulin resistance in rodents. The aim of the present study was to explore noise-induced processes underlying impaired insulin sensitivity in mice. METHODS: Male ICR mice were randomly divided into four groups: a control group without noise exposure and three noise groups exposed to white noise at a 95-dB sound pressure level for 4 h/day for 1, 10, or 20 days (N1D, N10D, and N20D, respectively). Systemic insulin sensitivity was evaluated at 1 day, 1 week, and 1 month post-noise exposure (1DPN, 1WPN, and 1MPN) via insulin tolerance tests (ITTs). Several insulin-related processes, including the phosphorylation of Akt, IRS1, and JNK in the animals' skeletal muscles, were examined using standard immunoblots. Biomarkers of inflammation (circulating levels of TNF-α and IL-6) and oxidative stress (SOD and CAT activities and MDA levels in skeletal muscles) were measured via chemical analyses. RESULTS: The data obtained in this study showed the following: (1) The impairment of systemic insulin sensitivity was transient in the N1D group but prolonged in the N10D and N20D groups. (2) Noise exposure led to enhanced JNK phosphorylation and IRS1 serine phosphorylation as well as reduced Akt phosphorylation in skeletal muscles in response to exogenous insulin stimulation. (3) Plasma levels of TNF-α and IL-6, CAT activity, and MDA concentrations in skeletal muscles were elevated after 20 days of noise exposure. CONCLUSIONS Impaired insulin sensitivity in noise-exposed mice might be mediated by an enhancement of the JNK/IRS1 pathway. Inflammation and oxidative stress might contribute to insulin resistance after chronic noise exposure.
Animals ; Biomarkers ; metabolism ; Inflammation ; physiopathology ; Insulin Receptor Substrate Proteins ; genetics ; metabolism ; Insulin Resistance ; genetics ; immunology ; MAP Kinase Signaling System ; physiology ; Male ; Mice ; Mice, Inbred ICR ; Mitogen-Activated Protein Kinase 8 ; genetics ; metabolism ; Noise ; adverse effects ; Oxidative Stress ; physiology ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; Random Allocation ; Time Factors

OBJECTIVETo study the ability of aqueous extract of Hericium erinaceus mushroom in the treatment of nerve injury following peroneal nerve crush in Sprague-Dawley rats.

METHODSAqueous extract of Hericium erinaceus was given by daily oral administration following peroneal nerve crush injury in Sprague-Dawley rats. The expression of protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) signaling pathways; and c-Jun and c-Fos genes were studied in dorsal root ganglia (DRG) whereas the activity of protein synthesis was assessed in peroneal nerves by immunohistochemical method.

RESULTSPeripheral nerve injury leads to changes at the axonal site of injury and remotely located DRG containing cell bodies of sensory afferent neurons. Immunofluorescence studies showed that DRG neurons ipsilateral to the crush injury in rats of treated groups expressed higher immunoreactivities for Akt, MAPK, c-Jun and c-Fos as compared with negative control group (P <0.05). The intensity of nuclear ribonucleoprotein in the distal segments of crushed nerves of treated groups was significantly higher than in the negative control group (P <0.05).

CONCLUSIONH. erinaceus is capable of promoting peripheral nerve regeneration after injury. Potential signaling pathways include Akt, MAPK, c-Jun, and c-Fos, and protein synthesis have been shown to be involved in its action.

Agaricales ; chemistry ; Animals ; Axons ; pathology ; Female ; Ganglia, Spinal ; metabolism ; Glucans ; analysis ; MAP Kinase Signaling System ; Nerve Crush ; Nerve Regeneration ; physiology ; Peripheral Nerves ; enzymology ; physiology ; Peroneal Nerve ; physiology ; Protein Biosynthesis ; Proto-Oncogene Proteins c-akt ; metabolism ; Proto-Oncogene Proteins c-fos ; genetics ; metabolism ; Proto-Oncogene Proteins c-jun ; genetics ; metabolism ; Rats, Sprague-Dawley

OBJECTIVETo investigate the role of extracellular signal-regulated kinase (ERK) in apoptosis of human colon cancer (HCT116) cells.

METHODSAfter the HCT116 cells were pretreated with specific ERK inhibitor (U0126) or specific siRNA and exposed to 10 mmol/L sodium butyrate (NaBT) for 24 h, their apoptosis was detected by flow cytometry, levels of SphK2 and ERK protein were measured by Western blot, and translocation of SphK2 was assayed by immunofluorescence microscopy.

RESULTSThe U0126 and siRNAs specific for SphK2 blocked the export of SphK2 from nuclei to cytoplasm and increased the apoptosis of HCT116 cells following NaBT exposure. Over-expression of PKD decreased NaBT-induced apoptosis of HCT116 cells, which was reversed by U0126. Furthermore, transfection of HCT116 cells with constitutively activated PKD plasmids recovered the U0126-blocked export of SphK2.

CONCLUSIONERK regulates the export of SphK2 and apoptosis of HCT116 cells by modulating PKD. Modulation of these molecules may help increase the sensitivity of colon cancer cells to the physiologic anti-colon cancer agent, NaBT.

Apoptosis ; drug effects ; physiology ; Butyric Acid ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; HCT116 Cells ; drug effects ; Humans ; Phosphotransferases (Alcohol Group Acceptor) ; genetics ; metabolism ; Protein Kinase C ; genetics ; metabolism ; RNA, Small Interfering ; Signal Transduction ; drug effects

Phospholipase C epsilon-1 (PLCE1) is a phospholipase C isoenzyme encoded by PLCE1 gene, and has more complicated molecular structure and function than other subtypes. Phospholipase C epsilon-1 is accepted the dual regulation by the upstream G proteins and GTP enzymes of Ras family. The downstream signal of PLCE1 is not only cause the Ca2+ flow and protein kinase C(PKC) activation, but also can be used as the GTP enzyme guanylic acid conversion factor of Ras superfamily, so as to regulate the expression of certain genes, adjusting cell growth and differentiation processes. PLCE1 plays a very important role in the signal transduction in the regulation of cell growth, differentiation, proliferation and apoptosis. Previous studies showed that phospholipase C epsilon-1 played an important role in the development of malignant tumors (especially the digestive tumors), heart disease, nephrotic syndrome and other diseases, but there are some questions about the mechanisms of PLCE1 involved in allergic rhinitis, this article will make an overview about PLCE1 promotes allergic rhinitis CD4+ T cells differentiate to Th2 cells by PKC-NF-κB pathway and Ras-MAPK pathway.
Apoptosis ; Calcium ; metabolism ; Cell Cycle ; Cell Differentiation ; physiology ; Cell Proliferation ; physiology ; Enzyme Activation ; Gene Expression ; Humans ; NF-kappa B ; Phosphoinositide Phospholipase C ; genetics ; physiology ; Protein Kinase C ; metabolism ; Rhinitis, Allergic ; enzymology ; Signal Transduction ; Th2 Cells ; cytology

Higher levels of body fat are associated with an increased risk for development numerous adverse health conditions. FTY720 is an immune modulator and a synthetic analogue of sphingosine 1-phosphate (S1P), activated S1P receptors and is effective in experimental models of transplantation and autoimmunity. Whereas immune modulation by FTY720 has been extensively studied, other actions of FTY720 are not well understood. Here we describe a novel role of FTY720 in the prevention of obesity, involving the regulation of adipogenesis and lipolysis in vivo and in vitro. Male C57B/6J mice were fed a standard diet or a high fat diet (HFD) without or with FTY720 (0.04 mg/kg, twice a week) for 6 weeks. The HFD induced an accumulation of large adipocytes, down-regulation of phosphorylated AMP-activated protein kinase alpha (p-AMPKalpha) and Akt (p-Akt); down-regulation of hormone-sensitive lipase (HSL), adipose triglyceride lipase (ATGL) and perilipin mRNA as well as up-regulation of phosphorylated HSL (p-HSL, Ser563) and glycogen synthase kinase 3 alpha/beta (p-GSK3alpha/beta). All these effects were blunted by FTY720 treatment, which inhibited adipogenesis and promoted lipolysis. Also, FTY720 significantly decreased lipid accumulation in maturing preadipocytes. FTY720 down-regulated the transcriptional levels of the PPARgamma, C/EBPalpha and adiponectin, which are markers of adipogenic differentiation. FTY720 significantly increased the release of glycerol and the expression of the HSL, ATGL and perilipin, which are regulators of lipolysis. These results show that FTY720 prevented obesity by modulating adipogenesis and lipolysis, and suggest that FTY720 is used for the treatment of obesity.
3T3-L1 Cells ; AMP-Activated Protein Kinases/metabolism ; Adipocytes/*drug effects/physiology ; Adipogenesis/drug effects ; Animals ; Anti-Obesity Agents/*pharmacology/therapeutic use ; Antigens, Differentiation/genetics/metabolism ; Carrier Proteins/genetics/metabolism ; Cell Size ; Diet, High-Fat/adverse effects ; Disease Models, Animal ; Enzyme Activation ; Gene Expression Regulation, Enzymologic/drug effects ; Glycogen Synthase Kinase 3/genetics/metabolism ; Lipase/genetics/metabolism ; Lipolysis/drug effects ; Male ; Mice ; Mice, Inbred C57BL ; Obesity/etiology/metabolism/*prevention & control ; Phosphoproteins/genetics/metabolism ; Phosphorylation ; Propylene Glycols/*pharmacology/therapeutic use ; Protein Processing, Post-Translational ; Proto-Oncogene Proteins c-akt/metabolism ; Sphingosine/*analogs & derivatives/pharmacology/therapeutic use ; Sterol Esterase/metabolism

The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) and phoshoinositide-3-kinase/protein kinase B (PI3K/Akt) signaling pathways play a major role in regulating cell growth, proliferation and apoptosis, via transmission of cell signals to cell nucleus. The genes, coding the MAPK/ERK and PI3K/Akt signaling cascade proteins, are significantly mutated in thyroid cancer. Genetic alternations contribute to aberrant activations and interaction of MAPK/ERK and PI3K/Akt signaling pathways in consequence of malignant follicular cell transformation and progression. This review focuses mainly on the role of genetic alterations in coding MAPK/ERK and PI3K/Akt signaling pathway proteins in generation, progression and diagnosis of thyroid cancer. Moreover, it additionally points out a therapeutic potential in restoring iodine avidity of thyroid cancer cells for radionuclide targeted treatment, by synergistically inhibiting activity of signaling pathways.
Extracellular Signal-Regulated MAP Kinases ; genetics ; metabolism ; Humans ; MAP Kinase Signaling System ; genetics ; Mitogen-Activated Protein Kinases ; genetics ; metabolism ; Mutation ; Phosphatidylinositol 3-Kinases ; genetics ; metabolism ; Proto-Oncogene Proteins c-akt ; genetics ; metabolism ; Signal Transduction ; genetics ; physiology ; Thyroid Neoplasms ; genetics ; physiopathology ; therapy

OBJECTIVETo investigate the effect of cytoskeleton reorganization inhibition with RNA interference on the activation of extracellular signal-regulated kinase (ERK1/2) in primary osteoblasts induced by fluid shear stress (FSS).

METHODSBALB/c mouse primary cultured osteoblasts were isolated by enzyme digestion technique. Osteoblasts were treated with LIM domain kinase 2 (LIM-2) specific siRNA or negative control siRNA, and then were loaded or unloaded by FSS of 1.2 Pa for 0, 5, 15, 30 and 60 min, respectively. The Western blotting was performed to detect the protein expression levels of P-ERK1/2 and ERK1/2, respectively. Two-way ANOVA and one-way ANOVA were used in data analysis.

RESULTSFSS loading for different time (0, 5, 15, 30, 60 min) treated with negative RNA inteference had significant effect on the levels of P-ERK/ERK ratio (0.047 ± 0.031, 0.253 ± 0.137, 0.390 ± 0.155, 0.613 ± 0.123, 0.680 ± 0.108, respectively, P < 0.01). Statistical analysis showed that there was significant interaction between FSS and cytoskeleton reorganization inhibition treated with RNA inteference on the levels of P-ERK/ERK ratio (P < 0.01). The levels of P-ERK/ERK ratio increased when osteoblasts were loaded for 5 - 15 min (0.623 ± 0.129 and 0.623 ± 0.064, respectively, P < 0.05) and returned to baseline at 30 min (0.333 ± 0.086), and then reached the peak at 60 min (0.667 ± 0.064, P < 0.01).

CONCLUSIONSFSS could activate ERK1/2 rapidly in primary cultured osteoblasts. Cytoskeleton reorganization inhibition treated with RNA interference speeded-up the activation of ERK1/2 by FSS, which could increase the sensitivity of ERK1/2 to FSS.

Animals ; Cells, Cultured ; Cytoskeleton ; metabolism ; physiology ; Lim Kinases ; genetics ; metabolism ; Mechanotransduction, Cellular ; Mice ; Mice, Inbred BALB C ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Osteoblasts ; cytology ; enzymology ; Phosphorylation ; RNA Interference ; RNA, Small Interfering ; Stress, Mechanical

BACKGROUNDThe relationship between apoptosis and tumors is a major focus in cancer research. RNA interference (RNAi) technology has emerged as a very potent tool to generate cellular knockdown phenotypes of a desired gene. The aim of this study was to explore the effect of siRNA specific to the protein casein kinase 2α (CK2α) on apoptosis of laryngeal carcinoma cells and to explore possible mechanisms.

METHODSAn siRNA expression plasmid specific to CK2α, psiRNA-hH1neo-CK2α, and a non-specific siRNA expression plasmid, psiRNA-hH1neo-cont, were constructed and transfected into Hep-2 cells by a lipofectamine method. The mRNA and protein levels of CK2α in transfected cells were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting analysis. Apoptosis was measured by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double-staining methods. The morphological changes to Hep-2 cells were observed under transmission electron microscopy (TEM). The levels of Bcl-2 and Bax proteins were measured by Western blotting analysis.

RESULTSLevels of CK2α mRNA and protein were significantly decreased in the psiRNA-hH1neo-CK2α group compared to the other groups (P < 0.05). The apoptotic rate of the psiRNA-hH1neo-CK2α transfected group was significantly higher compared to that in the untransfected group and the siRNA-hH1neo-cont transfected group (25.66% ± 0.83%, 3.66% ± 0.43%, and 5.18% ± 0.22%) (P < 0.05). Compared with the untransfected group and the siRNA-hH1neo-cont transfected group, the psiRNA-hH1neo-CK2α transfected group presented with classical ultrastructural features of apoptosis, such as karyopyknosis, chromatic agglutination adjacent to the nuclear membrane, and apoptotic bodies. Compared with the other two groups, the level of Bcl-2 protein in the psiRNA-hH1neo-CK2α transfected group was decreased (0.20 ± 0.09 vs. 0.72 ± 0.16, 0.56 ± 0.11, P < 0.01), while the Bax protein level was increased (0.81 ± 0.17 vs. 0.26 ± 0.12, 0.33 ± 0.17, P < 0.01) and the ratio of Bcl-2 to Bax was decreased (0.25 ± 0.05 vs. 2.76 ± 0.21, 1.70 ± 0.22, P < 0.01).

CONCLUSIONSThe siRNA expression plasmid specific to CK2α could suppress CK2α expression and induce the apoptosis of laryngeal carcinoma cells. This is possibly by decreasing the Bcl-2/Bax ratio. CK2α may provide a potential therapeutic target against human laryngeal carcinoma.

Apoptosis ; genetics ; physiology ; Blotting, Western ; Casein Kinase II ; genetics ; Hep G2 Cells ; Humans ; Laryngeal Neoplasms ; genetics ; metabolism ; Microscopy, Electron, Transmission ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; bcl-2-Associated X Protein ; genetics ; metabolism

OBJECTIVETo investigate the effect of Syk on the VEGF-C expression in breast cancer.

METHODSImmunohistochemical EnVision method was used to detect the protein expression of Syk, NFκB and VEGF-C in breast carcinoma; and the relationship between protein expression of Syk, NFκB, VEGF-C and lymph node metastasis was analysed. MDA-MB-231 cells were transfected with pcDNA3.1(-)-Syk, and the effect of Syk gene on the VEGF-C and NFκB expression was determined.

RESULTSIn the lymph node metastatic group, a lower expression rate of Syk and higher expression rate of VEGF-C and NFκB were detected as compared to the non-metastatic group. The expression of Syk was negatively associated with NFκB (r = -0.448, P = 0.002) and VEGF-C (r = -0.620, P = 0.000) expression, and VEGF-C was associated with the nuclear expression of NFκB (r = 0.310, P = 0.036). Compared with the non-transfected cells, the pcDNA3.1(-)-Syk transfected MDA-MB-231 cells showed significantly lower transcriptional level of VEGF-C mRNA, expression level of VEGF-C protein and NFκB activity (P < 0.05).

CONCLUSIONSSyk may play an important role in the lymph node metastasis of breast cancer. It may down-regulate the expression of VEGF-C by inhibiting the activity of NFκB, which thus suppresses lymph node metastasis of breast cancer.

Adult ; Aged ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Carcinoma, Ductal, Breast ; genetics ; metabolism ; pathology ; Carcinoma, Lobular ; genetics ; metabolism ; pathology ; Carcinoma, Medullary ; genetics ; metabolism ; pathology ; Cell Line, Tumor ; Female ; Genetic Vectors ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; physiology ; Lymphatic Metastasis ; Middle Aged ; NF-kappa B ; metabolism ; Plasmids ; Protein-Tyrosine Kinases ; genetics ; metabolism ; physiology ; RNA, Messenger ; metabolism ; Syk Kinase ; Transfection ; Vascular Endothelial Growth Factor C ; genetics ; metabolism

BACKGROUNDStudies indicated that Mer might be the main contributor to the specific internalization of photoreceptor outer segments (POS) in retinal pigment epithelium (RPE). It is very important to understand the mechanism of POS phagocytosis under the pathway of Mer and its ligands. The objective of this study was to identify changes in gene expression profiles caused by Mer gene knockout (Mer-/-) during phagocytosis of POS in RPE.

METHODSRPE from both Mer-/- and wild-type (WT) mice were isolated and cultured to the 3rd passage. POS were subjected to culture medium with 20 nmol/L Gas6 and protein S to activate specific mer-mediated phagocytosis. RPE phagocytosis was evaluated by phagocytosis assays and differential gene expression identified by microarray at 3 and 12 hours; the 0-hour time point served as the control. Three independent samples for each Mer-/- or WT RPE were subjected to the same protocol of microarray. Five genes were confirmed by real-time quantitative PCR (QPCR).

RESULTSThe Mer-/- RPE had less internalized POS than WT RPE after both 3 and 12 hours in phagocytosis assay. Compared to WT RPE and the 0-hour control, 38 and 45 different known genes were increased and 68 and 59 known genes were decreased in Mer-/- RPE after 3 and 12 hours, respectively. Abnormal POS phagocytosis in Mer-/- RPE was associated with significant gene expression changes in, for example, signal transduction (WNT, MAPK), phagocytosis (Vav3, Hsd11b1), cytoskeleton components (Myo7a), and metabolism, in a time-specific manner. QPCR results showed Vav3, Hsd11b1, Myo7a, Rtn2 and Itga8 in those independent samples were consistent with microarray.

CONCLUSIONGene expression profiles modulated in a time-specific manner in Mer-/- RPE indicate a possible internalization mechanism for abnormal POS phagocytosis, which gives insight into the mechanism of retinitis pigmentosa caused by the mutation of MerTK in humans.

Animals ; Gene Expression Profiling ; Mice ; Mice, Knockout ; Mice, Mutant Strains ; Oligonucleotide Array Sequence Analysis ; Phagocytosis ; genetics ; physiology ; Proto-Oncogene Proteins ; genetics ; metabolism ; Receptor Protein-Tyrosine Kinases ; genetics ; metabolism ; Retinal Pigment Epithelium ; cytology ; Reverse Transcriptase Polymerase Chain Reaction ; Tissue Culture Techniques ; c-Mer Tyrosine Kinase