AIMTo investigate the effects of blockers of the three kinds of potassium channels: voltage-dependent K+ channel(KV), calcium-activated K+ channel(KCa) and ATP-sensitive K+ channel(KATP), on the proliferation of rat bronchial smooth muscle cells (BSMCs).

METHODSThe effects of three kinds of potassium channel blockers on the proliferation of BSMCs were detected by MTT method, immunocytochemistry staining and flow-cytometry. Their effects on the dynamic changes of Ca2+ concentration in BSMCs were investigated by the fluorophotometry of Fura-2/AM.

RESULTSThe KV blocker 4-aminopyridine (4-AP) was shown to significantly increase the expression of proliferating cell nucleus antigen in cultured rat BSMCs (P < 0.01), but the KCa blocker tetraethylammonium (TEA) and KATP blocker glibenclamide(Glib) did not show such effect (P > 0.05). 4-AP was found to significantly increase the optical density value of the cultured BSMCs (P < 0.01) by MTT method and the numbers of S + G2M BSMCs(P < 0.05) by flow-cytometry. TEA and Glib did not show such effects. 4-AP significantly increased the Ca2+ concentration in cultured BSMCs(P < 0.01). TEA and Glib did not show such effects.

CONCLUSIONThis result suggests that inhibition of KV activity can increase intracellular Ca2+ and proliferation of rat BSMCs, but inhibition of KCa and KATP showed no effect.

4-Aminopyridine ; pharmacology ; Animals ; Bronchi ; cytology ; Calcium ; metabolism ; Cell Division ; drug effects ; Cells, Cultured ; Glyburide ; pharmacology ; Muscle, Smooth ; drug effects ; metabolism ; Potassium Channel Blockers ; pharmacology ; Potassium Channels, Calcium-Activated ; antagonists & inhibitors ; Potassium Channels, Voltage-Gated ; antagonists & inhibitors ; Proliferating Cell Nuclear Antigen ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tetraethylammonium ; pharmacology

The main factors which affected the isolation, purification and cultivation of Pinellia cordata protoplasts from leaves were studied. The results indicated that the optimum enzyme solution for P. cordata leaves was 13% CPW + 1.0% Cellulose +0.1% Pectolase, at pH 6.0, temperature (25-28 degrees C ) for 4 h. The sucrose density gradient centrifugation was adopted to purificate the protoplasts collected, when 25% sucrose was used as mediator, centrifugating at 500 rpm for 10 min. When the protoplasts were shallow liquid and liquid-solid double layer cultured on the medium of MS + 0.5 mg x L(-1) 6-BA + 0.25 mg x L(-1) NAA + 13% mannitol at the density of 2.5 x 104 protoplasts/mL, or fed and nursed cultured at the density of 100-500 protoplasts/mL, cell division could be observed for 3 days; granular calli appeared for 30 days. Calli was proliferated on the medium of MS + 0.5 mg x L(-1) 6-BA + 0.25 mg x L(-1) NAA solidified by 0.55% agar, and differentiated and regenerated after 5-6 months. Plant generation of P. cordata is successfully established.
Cell Separation ; methods ; Culture Media ; Pinellia ; physiology ; Protoplasts ; physiology ; Regeneration

Amino Acid Sequence ; Base Sequence ; Genes, Bacterial ; Humans ; Molecular Sequence Data ; Polymerase Chain Reaction ; Staphylococcus epidermidis ; enzymology ; genetics ; beta-Lactamases ; chemistry ; genetics

The effect of protein kinase C (PKC) signaling pathway on the activity of voltage-dependent delayed rectifier potassium channel (K(V)) and the expression of K(V) isoform K(V)1.5 in rat bronchial smooth cells (BSMCs) were investigated with whole-cell patch clamp, Western-blot and RT-PCR techniques. The results showed: (1) phorbol 12-myristate 13-acetate (PMA), a PKC activator, caused a significant inhibition of K(V) channel currents in rat BSMCs. The inhibition was partly abolished by Ro31-8220, a PKC inhibitor. (2) PMA caused a significant suppression of the expression of K(V)1.5 mRNA and protein in rat BSMCs. These effects were attenuated by Ro31-8220. The results suggest that in rat BSMCs PKC activation inhibits K(V) currents and down-regulates the expression of K(V)1.5.
Animals ; Bronchi ; cytology ; Cells, Cultured ; Female ; Indoles ; pharmacology ; Kv1.5 Potassium Channel ; genetics ; physiology ; Male ; Membrane Potentials ; physiology ; Myocytes, Smooth Muscle ; cytology ; physiology ; Patch-Clamp Techniques ; Protein Kinase C ; metabolism ; physiology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Tetradecanoylphorbol Acetate ; pharmacology

Adult ; Aged ; Coronary Disease ; therapy ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Sirolimus ; administration & dosage ; Stents ; adverse effects ; Thrombosis ; etiology

This study is to investigate the expression of CyclinD1 in asthmatic rats and construct expression plasmids of sense and antisense CyclinD1 gene and transfect them to asthmatic airway smooth muscle cell to study the effects of CyclinD1 on the proliferation of airway smooth muscle cells in asthmatic rats. CyclinD1 cDNA was obtained by RT-PCR of total RNA extracted from the airway smooth muscle in asthmatic rats. The sequence was inserted into eukaryotic expression vector pcDNA3.1 (+) to recombinate the sense and antisense pcDNA3.1-CyclinD1 eukaryotic expression vector. The two recombinations and vector were then separately transfected into airway smooth muscle cell in asthmatic rats by using liposome. The expression level of CyclinD1 was certificated by Western blotting analysis. The proliferations of ASMCs isolated from asthmatic rats were examined with cell cycle analysis, MTT colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemical staining. Results showed (1) Compared with control group, the content of CyclinD1 was significantly increased; (2) It was comformed by restriction endonucleasa digestion and DNA sequence analysis that the expression plasmid of sense and antisense CyclinD1 were successfully recombinated. There was significant change of CyclinD1 expression between vector and sense CyclinD1 transfected cells, and the expression level of CyclinD1 in ASMC transfected with antisense CyclinD1 was lower than that in vector transfected cells (P <0.01); (3) In the asthmatic groups, compared with the vecter group, the percentage of S + G2M phase, absorbance A value of MTT and the expression rate of PCNA protein in ASMC transfected with pcDNA3. 1-CyclinD1 vector significantly increased. The values decreased remarkably in the pcDNA3,1-as CyclinD1 group. Statistical analysis revealed that there were significant differences in these indicators of cell proliferation in three groups (P <0.01). In the normal groups, statistical analysis revealed that there were significant differences in the percentage of S + G2M phase, a value of MTT and the expression rate of PCNA protein in three groups (P <0.01). Sense CyclinD1 eukaryotic expression vectors could have a positive effect on the proliferation of ASMC, however the antisence one have a negative effect, which implicated that CyclinD1 might contribute to the process of airway smooth muscle cell proliferation.
Animals ; Asthma ; pathology ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Codon ; genetics ; pharmacology ; Cyclin D1 ; agonists ; antagonists & inhibitors ; genetics ; DNA, Antisense ; genetics ; pharmacology ; Disease Models, Animal ; Gene Expression ; Genetic Vectors ; genetics ; Male ; Myocytes, Smooth Muscle ; drug effects ; pathology ; Rats ; Rats, Sprague-Dawley ; Recombination, Genetic ; genetics ; Respiratory System ; Reverse Transcriptase Polymerase Chain Reaction ; Transduction, Genetic ; Transfection

The purpose of this study was to explore the effect of proteasome inhibitor, bortezomib (Bzb), on osteoblast in pathologic status of myeloma bone disease. The myeloma bone disease was modeled by co-culture of mouse myeloma cell RPMI8226 with osteoblast line MC-3T3E1 from mouse calvaria, and intervenient culture of supernatant. The inhibitory effect of Bzb on proliferation of MC-3T3E1 assayed by modified MTT method, the apoptosis of MC-3T3E1 cells was determined by flow cytometry with Annexin V/PI staining, the expressions of osteoblast markers, Runx2/cbfa1, osteocalcin (OCN) and osterix (OSX) in MC-3T3E1 treated with Bzb were detected by RT-PCR and Western blot respectively. Experiments were divided into 3 group: single cultured, co-cultured and supernatant-interveniently cultured groups. The results showed the Bzb in higher concentration inhibited proliferation of MC-3T3E1 cells in a dose-dependent manner, with the IC(50) of 38.1 nmol/L for 48 hours, the Bzb in low concentration (5 nmol/L) did not show the inhibitory effect on proliferation of MC-3T3E1 in single cultured group (p>0.10), but could decrease apoptotic rate of MC-3T3E1 by 32.5% and 24.6% respectively in cocultured and supernatant-interveniently cultured groups, moreover increased the expression of osteoblast-related gene OSX, OCN mRNA and protein (p<0.05), while no obvious change of Runx2/cbfa1 expression was observed (p>0.05). It is concluded that the proteasome inhibitor, Bzb, in low concentration promotes the activity of osteoblast internal mechanisms, and prevents the apoptosis of osteoblasts induced by myeloma cells. In addition, it can up-regulate transcription and expression of osteoblast markers related to Runx2/cbfa1 path way, thus may protect osteoblasts in myeloma bone disease.
3T3 Cells ; Animals ; Apoptosis ; drug effects ; Boronic Acids ; pharmacology ; Bortezomib ; Cell Line, Tumor ; Mice ; Multiple Myeloma ; pathology ; Pyrazines ; pharmacology

BACKGROUNDAirway smooth muscle (ASM) is suspected to be a determining factor in the structural change of asthma. However, the role of protein kinase C alpha (PKCalpha) and cyclin D1 involved in the dysfunction of ASM leading to asthmatic symptoms is not clear. In this study, the central role of PKCalpha and cyclin D1 in ASM proliferation in asthmatic rats was explored.

METHODSThirty-six pathogen-free male Brown Norway (BN) rats were randomly divided into 2 groups: control groups (group N1, N2 and N3) and asthmatic groups (group A1, A2, and A3). Groups A1, A2 and A3 were challenged with ovalbumin (OA) for 2 weeks, 4 weeks and 8 weeks respectively. Control animals were exposed to an aerosolized sterile phosphate buffered saline (PBS). The ASM mass and nucleus numbers were studied to estimate the degree of airway remodeling by the hematoxylin-eosin staining method. PKCalpha and cyclin D1 expression in the ASM cells was detected by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The relation between PKCalpha and cyclin D1 was assessed by linear regression analysis. PKC agonist phorbol 12-myristate 13-acetate (PMA), PKC inhibitor Ro31-8220 and an antisense oligonucleotide against cyclin D1 (ASOND) were used to treat ASM cells (ASMCs) obtained from the 2 weeks asthmatic rats. The cyclin D1 protein expression level was detected by Western blotting.

RESULTSCompared with the control group, the PKCalpha and cyclin D1 mRNA levels were increased in the asthmatic group. Similar to RT-PCR results, immunohistochemistry analysis for PKCalpha and cyclin D1 expression revealed an increased production in ASMCs after allergen treatment for 2, 4 and 8 weeks compared with the respective control groups. No difference in expression of PKCalpha and cyclin D1 in ASM were found in the 2, 4 or 8 weeks asthmatic rats. There were significant positive correlations between PKCalpha and cyclin D1 expression, both transcriptionally (r = 0.944, P < 0.01) and translationally (r = 0.826, P < 0.01), in ASM. The content of cyclin D1 in asthmatic ASMCs increased after being stimulated by PMA, and decreased when induced by Ro31-8220. ASOND targeting for cyclin D1 lowered the expression of cyclin D1 induced by PMA.

CONCLUSIONSIncreased expression of PKCalpha and cyclin D1 in ASM along with smooth muscle structure changes might implicate PKCalpha and cyclin D1 participation in the proliferation of ASM and contribute to the pathogenesis of asthma after repeated allergen exposure in rats. The results suggested that cyclin D1 might be downstream of PKC signal transduction pathway.

Animals ; Asthma ; pathology ; Cell Proliferation ; Cyclin D1 ; genetics ; physiology ; Lung ; pathology ; Male ; Myocytes, Smooth Muscle ; pathology ; Protein Kinase C-alpha ; genetics ; physiology ; RNA, Messenger ; analysis ; Rats ; Rats, Inbred BN

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