Cyclic nucleotide second messages (cAMP and cGMP) play a central role in signal transduction and regulation of physiologic responses. The only way to inactivate them is to degrade them through the action of phosphodiesterases (PDEs). Recent advances show that PDE4, a cAMP specific phosphodiesterase, has specific functions in regulating the activities of the cardiovascular system. PDE4 is expressed in the cells of cardiovascular systems including cardiomyocytes, vascular smooth muscle cells, and vascular endothelial cells. The expression level of PDE4 is shown to be downregulated in the failure hearts, while it is upregulated in hypertrophied hearts. And PDE4 deficiency in mice is associated with a cardiac phenotype comprised of a progressive, age-related cardiomyopathy, accelerated heart failure after myocardial infarction and exercise-induced arrhythmias. Local levels of cAMP regulate the precise opening of the ryanodine receptor complex (RyR2) which releases calcium at the start of a heartbeat. Loss or inhibition of PDE4 activity increases calcium flow through RyR2, and causes leakiness and heart failure in mice. These finding may show us a new target for treating cardiovascular diseases.
Animals ; Cardiovascular System ; enzymology ; Cyclic AMP ; physiology ; Cyclic Nucleotide Phosphodiesterases, Type 4 ; chemistry ; physiology ; Humans ; Muscle, Smooth, Vascular ; enzymology ; Myocytes, Cardiac ; enzymology ; Phosphodiesterase 4 Inhibitors ; Signal Transduction

Cysteine and aspartic proteases possess high elastolytic activity and might contribute to the degradation of the abdominal aortic aneurysm (AAA) wall. The aim of this study was to analyze, in detail, the proteases (cathepsins B, D, K, L and S, and inhibitor cystatin C) found in human AAA and healthy aortic tissue samples. The vessel walls from AAA patients (n=36) and nonaneurysmal aortae (n=10) were retrieved using conventional surgical repair and autopsy methods. Serum samples from the same AAA patients and 10 healthy volunteers were also collected. Quantitative expression analyses were performed at the mRNA level using real-time reverse transcriptase-PCR (RT-PCR). Furthermore, analyses at the protein level included western blot and immunoprecipitation analyses. Cellular sources of cysteine/aspartic proteases and cystatin C were identified by immunohistochemistry (IHC). All cysteine/aspartic proteases and cystatin C were detected in the AAA and control samples. Using quantitative RT-PCR, a significant increase in expression was observed for cathepsins B (P=0.021) and L (P=0.018), compared with the controls. Cathepsin B and cystatin C were also detected in the serum of AAA patients. Using IHC, smooth muscle cells (SMCs) and macrophages were positive for all of the tested cathepsins, as well as cystatin C; in addition, the lymphocytes were mainly positive for cathepsin B, followed by cathepsins D and S. All cysteine/aspartic proteases analyzed in our study were detected in the AAA and healthy aorta. The highest expression was found in macrophages and SMCs. Consequently, cysteine/aspartic proteases might play a substantial role in AAA.
Aged ; Aorta/enzymology ; Aortic Aneurysm, Abdominal/*enzymology ; Aspartic Acid Proteases/genetics/*metabolism ; Case-Control Studies ; Cathepsins/genetics/metabolism ; Cysteine Proteases/genetics/*metabolism ; Humans ; Lymphocytes/enzymology ; Macrophages/enzymology ; Middle Aged ; Myocytes, Smooth Muscle/enzymology ; RNA, Messenger/genetics/metabolism

OBJECTIVETo investigate whether extracellular signal-regulated kinase (ERK1/2) was involved in changes of vascular smooth muscle cell (VSMC) under hypertension.

METHODSTwo-kidney one clip Wistar hypertensive rats (WHR) were sacrificed and their right kidneys were harvested 4 weeks after surgery. The spontaneously hypertensive rats (SHR) were divided into 4, 8, and 16 weeks old groups (SHR4w, SHR8w, and SHR16w), respectively. The control group were sham operated age-matched Wistar rats. Immunohistochemical technique and Western blotting were applied to study ERK1/2 protein expression in VSMC of the renal vascular trees in WHR, SHR, and control rats.

RESULTSBlood pressure in two-kidney one clip WHR obviously increased at one week after surgery, and reached to 198. 00 +/- 33. 00 mm Hg at the end of experiment, significantly higher than that in the control rats (P < 0.01). Blood pressure in SHR4w (108.00 +/- 11.25 mm Hg) was similar to that in the controls. However, it rose to 122.25 +/- 21.75 mm Hg in SHR8w, and even up to 201.75 +/- 18.00 mm Hg in SHR16w, which were significantly higher than that of both the SHR4w and the controls (P < 0.01). The rate and degree of glomerular fibrosis in WHR were significantly higher than controls (P < 0.05). Hyaline degeneration of the afferent arterioles was found in WHR. In contrast, either fibrosis of glomerulus or hyaline degeneration of the arterioles or protein casts was not observed in SHR4w, SHR8w, and SHR16w. Immunohistochemical staining results showed expression of ERK1 was similar to that of ERK2. The positive rates of ERK2 staining in VSMC of afferent arterioles, interlobular, interlobar, and arcuate arteries in two-kidney one clip WHR were significantly higher (7.09% +/- 1.75%, 14.57% +/- 4.58%, 29.44% +/- 7.35%, and 13.63% +/- 3. 85%, respectively) than that of the controls(P < 0.01). The positive rates of ERK2 staining in VSMC at afferent arterioles, interlobular, interlobar, and arcuate arteries in SHR16w were significantly higher (12.09% +/- 1.40%, 24.17% +/- 6.92%, 32.44% +/- 4.05%, and 18.61% +/- 3.35%, respectively) than that of the controls (P < 0.01), too. The expression of ERK1/2 protein of kidney in WHR and SHR16w was significantly higher than that in the controls by Western blotting assay (P < 0.01).

CONCLUSIONExtracellular signal transduction system are highly expressed in kidney VSMC of two-kidney one clip WHR and SHR. Phospho-ERKI/2 may play an important role in VSMC hypertrophy and hyperplasia under hypertension.

Animals ; Arterioles ; enzymology ; Fibrosis ; Hypertension ; metabolism ; pathology ; Kidney Glomerulus ; blood supply ; pathology ; Male ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; enzymology ; Rats ; Rats, Inbred SHR ; Rats, Wistar

Reactive oxygen species generated by NADPH oxidase enhance aortic vascular smooth muscle cell proliferation and migration which play an important role in the pathophysiology of atherosclerosis. We investigated the role of NADPH oxidase in the cellular cholesterol metabolism in vascular smooth muscle cells using p47phox-deficient cells. Wild-type and p47phox knockout vascular smooth muscle cells were loaded with cholesterol for 72 h by using 10 mg/L cholesterol:methyl-beta-cyclodextrin complexes and then incubated with or without 0.3 mg/L thrombin for 10 min. Foam cell formation was determined by accumulation of intracellular cholesterol, oil Red O-stained lipid droplets. After cholesterol loading, cellular lipid droplets raised sharply, cellular cholesterol increased from (31.4+/-2.0) to (61.0+/-2.1) mg/g protein (P<0.05) in wild-type cells, and from (29.8+/-2.5) to (51.3+/-3.1) mg/g protein (P<0.05) in p47phox deficient cells, but the difference between the two cell types was not significant. Immunostaining showed decreased levels of smooth muscle alpha-actin and increased levels of macrophage marker Mac-2 in both wild-type and p47phox deficient vascular smooth muscle cells. One of the macrophage-related inflammation genes, monocyte chemoattractant protein-1 (MCP-1) expression did not change in both two cell types detected by immunostaining. Although additional incubating with thrombin, another macrophage-related inflammation gene, vascular cell adhesion molecule-1 (VCAM-1) expression was similar in all groups analyzed by real-time RT-PCR. However, the expression of ATP-binding cassette transporter A1 (ABCA1), acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1), the key proteins in cellular cholesterol metabolism, were similarly increased (P<0.05) in both two cell types as determined by quantitative real-time RT-PCR and Western blot, and it was not related to the state of oxidative stress. Interestingly, the expression of adipophilin, the lipid droplet related protein, had the similar results with ABCA1 and ACAT1, but, in wild-type cells, its expression also increased merely incubating with thrombin as determined by quantitative real-time RT-PCR. Together, these results suggest that p47phox-dependent NADPH oxidase is not involved in transdifferentitation of vascular smooth muscle cells into macrophage-like state after cholesterol loading. Deleting p47phox gene does not affect the cellular cholesterol metabolism in vascular smooth muscle cells.
ATP-Binding Cassette Transporters ; metabolism ; Chemokine CCL2 ; metabolism ; Cholesterol ; metabolism ; Foam Cells ; cytology ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; enzymology ; NADPH Oxidases ; metabolism ; RNA, Messenger ; Sterol O-Acyltransferase ; metabolism ; beta-Cyclodextrins ; pharmacology

Proliferation of vascular smooth muscle cells (VSMCs) is often accompanied by changes in intracellular actin distribution. The changes are controlled by the signal transduction pathways of protein kinase C/mitogenic activated protein kinase (PKC-MAPK), but the mechanism is unclear. In order to study the effect of insulin on the intracellular signal transduction (PKC-MAPK) probably involved in the modulation of proliferation and redistribution of actins in the VSMCs, the DNA synthesis, MAPK activities and its gene expression, and the redistribution of intracellular actins were investigated in the isolated VSMCs of SHR pretreated with PKC inhibitor and/or insulin, respectively. We found that insulin treatment resulted in proliferation of the VSMCs and an increase in [(3)H] TdR incorporation. Meanwhile, the activities and expression of MAPK increased significantly compared to the control group. These effects of insulin were blocked by PKC inhibitor. In addition, insulin caused a redistribution of the intracellular actins in VSMCs, which was also inhibited by PKC inhibitor. It is, therefore, suggested that these effects of insulin on VSMCs proliferation and distribution of the intracellular actins may be mediated by the MAPK signal transduction pathway.
Actins ; metabolism ; Animals ; Cell Division ; drug effects ; In Vitro Techniques ; Insulin ; pharmacology ; Mitogen-Activated Protein Kinases ; physiology ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; drug effects ; enzymology ; metabolism ; Protein Kinase C ; physiology ; Rats ; Rats, Inbred SHR ; Tissue Distribution

OBJECTIVETo investigate the therapeutic effect of Dachaihutang on the development of atherosclerosis (AS) in rabbits and its possible mechanism by detecting the expression level of carnitine patmitoyl transferase-1 (CPT-1) in vascular smooth muscle layer of atherosclerotic rabbits, and search the new way and evidence for AS cures.

METHODThirty six male New Zealand white rabbits were divided randomly into control group, model control group, simvastatin group and Chinese traditional medicine dachaihutang group. After 9 weeks and 20 weeks of treatment, serum total cholesterol (TC) and triglyceride (TG) and low-density lipoprotein (LDL) levels were examined. At the end of 25 th weeks, histological changes in ascending aorta were studied by HE staining and histomorphometric analysis. The gene expression of CPT-1 in vascular smooth muscle layer of thoracic aorta was detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTCompared with model control group, in dachaihutang group serum TC and TG and LDL levels attenuated. Pathomorphology indicated that intima and media (I + M) became thinned, and the ratios of the thickness of intima to media(I/M) and the area of intima to media (SI/SM) were decreased (P < 0.05). Aortic intimal proliferation in Dachaihutang group was associated with a marked increase in CPT-1 expression in vascular smooth muscle layer of thoracic aorta. Compared to simvastatin group, except TG value, other values were higher in Dachaihutang group, however, there were no significant differences between the two groups.

CONCLUSIONThese findings suggest that early treatment with Dachaihutang not only induces a significant regression of arterial lesions of high cholesterol diet rabbits, but also has a crucial inhibited genesis and development of atherosclerosis effect by up-regulating CPT-1 expression in vascular smooth muscle layer.

Animals ; Aorta ; cytology ; drug effects ; enzymology ; Atherosclerosis ; drug therapy ; enzymology ; genetics ; Carnitine O-Palmitoyltransferase ; genetics ; metabolism ; Disease Models, Animal ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression ; drug effects ; Humans ; Male ; Myocytes, Smooth Muscle ; drug effects ; enzymology ; Rabbits ; Random Allocation

To investigate the effect of cigarette smoke extract (CSE) on the role of protein kinase C (PKC) in the proliferation of passively sensitized human airway smooth muscle cells (HASMCs). After synchronization of cultured HASMCs, they were divided into a group A and Group B. The group A was treated with normal human serum and served as controls and the group B was treated with the serum of asthma patients. The group A was further divided into group of A1, A2 and A3 and the group B was sub-divided into the group of B1, B2, B3, B4 and B5. No other agents were added to the group A1 and B1. The cells of group A2 and B2 were stimulated with 5% CSE for 24 h. HASMCs from group A3 and B3 were treated with PKC agonist PMA (10 nmol/L) and CSE (5%) for 24 h. PKC inhibitor Ro-31-8220 (5 micromol/L) was added to the HASMCs of group B4 for 24 h. The cells from group B5 were stimulated with Ro-31-8220 (5 micromol/L) and CSE (5 %) for 24 h. The proliferation of HASMCs isolated from group A and B was examined by cell cycle analysis, MTT colorimetric assay and 3H-TdR incorporation test. The expression of PKC-a in each group was observed by Western blotting and RT-PCR, respectively. The results showed that the percentage of S phase, absorbance (A) value, the rate of 3H-TdR incorporation, the ratios of A value of PKC-alpha mRNA and the A value of PKC-alpha protein in HASMCs from group B1, B2 and B3 were significantly increased compared to those of group A1, A2 and A3 correspondingly and respectively (P< 0.01). The proliferation of HASMCs of group A2 and B2 stimulated with CSE and group A3 and B3 stimulated with CSE and PMA were also significantly enhanced when group A1, A2 and A3 and group B1, B2 and B3 compared to each other (P<0.05, P<0.01, respectively). The percentage of S phase, absorbency (A) value, 3H-TdR incorporation rate, the ratios of A value of PKC-alpha mRNA and the A value of PKC-alpha protein in HASMCs from group B4 treated with Ro-31-8220 and group B5 treated with CSE and Ro-31-8220 were significantly decreased as compared to those of group B1 and B2 correspondingly and respectively (P<0.05, P<0.01). It was concluded that CSE can enhance the passively sensitized HASMC proliferation and the expression of PKC alpha. PKC and its alpha subtype may contribute to this process. Our results suggest cigarette may play an important role in ASMCs proliferation of asthma through PKC signal pathway.
Asthma/*blood ; Bronchi/cytology ; Bronchi/metabolism ; Cell Cycle/drug effects ; Cell Proliferation ; Cells, Cultured ; Culture Media ; Myocytes, Smooth Muscle/*cytology ; Myocytes, Smooth Muscle/enzymology ; Protein Kinase C/biosynthesis ; Protein Kinase C/*physiology ; Serum ; Signal Transduction ; Tobacco/adverse effects ; Tobacco Smoke Pollution/*adverse effects

AIM AND METHODSTo investigate the role of mitogen-activated protein kinase phosphatase-1 (MKP-1) in the regulation of cells proliferation, the expression of MKP-1 and extracellular signal-regulated kinase-1 (ERK-1) in heart and aorta of spontaneous hypertensive rat (SHR) and WKY were studied. We also investigated the effect of MKP-1 genes,which were transfected into vascular smooth muscle cells (VSMC) using the classical calcium phosphate coprecipitation technique, on the incorporation of 3H-TdR in VSMC stimulated by angiotensin II (Ang II).

RESULTS(1) Compared with that of WKY, MKP-1 expression in heart and aorta were significantly decreased by 53% (P < 0.01) and 45% (P < 0.01) in SHR, respectively. While the expression of ERK-1 in heart and aorta of SHR were higher than that of WKY (P < 0.01). The ratio of ERK-1/MKP-1 in heart and aorta of SHR were significantly higher than that of WKY. (2) 3H-TdR incorporation in VSMC stimulated by Ang II (10(-7) mol/L) was increased by 207% (P < 0.01), compared with control group. In the transfected cells with wild MKP-1 gene, Ang II-induced incorporation of 3H-TdR lowered 63%, compared with untransfected cells (P < 0.05). There were no marked inhibitive role between mutant MKP-1-transfected cells and blank vector-transfected cells in response to Ang II, compared with Ang II group (P > 0.05).

CONCLUSIONThese results showed that the expression of ERK-1 in heart and aorta isolated from SHR, which stimulated proliferation and hypertrophy of cells, is higher than that of MKP-1 which dephosphorylates and inactivated ERK-1. In addition, MKP-1 significantly inhibits Ang II-stimulated proliferation of VSMC.

Angiotensin II ; pharmacology ; Animals ; Aorta ; cytology ; enzymology ; Cell Proliferation ; Cells, Cultured ; Dual Specificity Phosphatase 1 ; metabolism ; Heart ; Hypertension ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Muscle, Smooth, Vascular ; cytology ; Myocardium ; cytology ; enzymology ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY

Animals ; Cell Proliferation ; drug effects ; Gene Expression Regulation, Enzymologic ; Glucuronidase ; antagonists & inhibitors ; genetics ; metabolism ; physiology ; Humans ; Myocytes, Smooth Muscle ; cytology ; Neoplasm Metastasis ; Neoplasms ; blood supply ; pathology ; Neovascularization, Pathologic ; enzymology ; Oligosaccharides ; pharmacology

To investigate the regulatory effect of extracellular signal-regulated kinase (ERK) signaling pathway on airway smooth muscle cell (ASMC) proliferation in chronic asthmatic rats, the rat model of chronic asthma was established, and ERK agonist epidermal growth factor (EGF) and inhibitor PD98059 were used in the cell culture. ASMC proliferation was examined by flow cytometry analysis, methyl thiazolyl tetrazolium (MTT) colorimetric assay, [(3)H]-thymidine (TdR) incorporation and proliferating cell nuclear antigen (PCNA) immunocytochemical staining. The expressions of ERK mRNA, ERK protein, phosphorylated ERK1/2 (p-ERK1/2) protein were observed by RT-PCR and Western blot. The results showed that in chronic asthmatic group, compared with that in the control group, the percentage of cells at G(0)/G(1) phase was significantly decreased and the percentage of cells at S+G(2)/M phase was significantly increased. Absorbance (A(490)), DNA synthesis and the expression of PCNA protein in ASMCs in chronic asthmatic group were significantly increased. The expressions of ERK mRNA, ERK1/2 protein, p-ERK1/2 protein and the activation ratio of ERK in ASMCs in chronic asthmatic group were significantly increased compared with those in the control group. After treatment with PD98059, the percentage of cells at S+G(2)/M phase, A(490), DNA synthesis and the expression of PCNA protein in ASMCs in chronic asthmatic group were significantly decreased; the expressions of ERK mRNA, ERK1/2 protein, p-ERK1/2 protein and the activation ratio of ERK in ASMCs in chronic asthmatic group were significantly decreased compared with those in the control group. After treatment with EGF, the percentage of cells at S+G(2)/M phase, A(490), DNA synthesis and the expression of PCNA protein in ASMCs in chronic asthmatic group were significantly increased compared with those before treatment; and PD98059 markedly inhibited the effect of EGF. These results suggest that the endogenous proliferation activity of ASMCs in chronic asthmatic rats significantly increases compared with that in the control rats, and ERK1/2 participates in this process. The ERK signaling pathway might play an important role in regulating ASMC proliferation, leading to asthmatic airway remodeling.
Animals ; Asthma ; enzymology ; pathology ; Bronchi ; pathology ; Cell Proliferation ; Cells, Cultured ; Chronic Disease ; Colorimetry ; Enzyme Activation ; Extracellular Signal-Regulated MAP Kinases ; analysis ; genetics ; physiology ; Flow Cytometry ; Myocytes, Smooth Muscle ; pathology ; Rats