Objective To observe the eotaxin expression of rat airway smooth muscle cells ( ASMCs) induced by serum from asthmatic rats, and explore the possible mechanism. Methods ASMCs isolated fromrat tracheas were cultured in vivo. Then they were treated with serum from asthmatic rats, or treated with serum and dexamethasone simultaneously. The level of eotaxin protein in supernatant and eotaxin mRNA in ASMCs were measured by ELISA and reverse transcription-polymerase chain reaction. The expression of cAMP in ASMCs was examined by radioimmunoassay. Results After the treatment with sensitized serum, the eotaxin level in supernatant and mRNA expression in ASMCs were significantly higher [ ( 107. 09 ±7. 12) ng/L vs. ( 0. 63 ±0. 56) ng/L, P lt; 0. 05; 1. 39 ±0. 04 vs. 0. 05 ±0. 01, P lt;0. 05] , and the level of cAMP in ASMCs was significantly lower compared with the control group [ ( 17. 58 ±3. 62) ng/L vs. ( 32. 39 ±3. 36) ng/L, P lt; 0. 05] . After intervened by the sensitized serum and dexamethasone simultaneously, the protein and mRNA expressions of eotaxin were lower compared with those intervened by sensitized serumalone [ ( 64. 18 ±4. 04) ng/L and 0. 77 ±0. 19] . The level of eotaxin in supernatant was negatively correlated with cAMP level in ASMCs ( r = - 0. 788, P lt; 0. 01) . Conclusions There is anautocrine function in ASMCs as inflammatory cells after stimulation with sensitized serum. Eotaxin may play an important roll in the pathogenesis of asthma via a cAMP-dependent pathway.
Objective To extract and identify primary culture rat pulmonary arterial smooth cells ( PASMCs) , and investigate the effects of hypoxia on the proliferation of PASMCs. Methods Rat PASMCs were separated by the method of tissue block anchorage, and the cellular morphology was observed under light microscope. The cells were identified by projection electron microscopy, and α-smooth muscle actin ( α-SMactin)in the cells was identified by immunohistochemistry and immunofluorescence. The primary cultured PASMCs were exposed to normoxic and/ or hypoxia condition for 2, 6, 12, 24, 48 hours respectively, thenMTT assay and PCNA ( proliferating cell nuclear antigen) immunohistochemistry were used to detect the proliferation of PASMCs. Results The cells tended to be long spindle and grew in the “peak-valley”mode under light microscope. Immunology results showed that endochylema was stained in brownish yellow, and the positive rate was beyond 96% . There were dense patch, dense body and many filaments in endochylema under projection electron microscopy. MTT assay demonstrated that the A values of PASMCs expose to hypoxia were higher than that of nomoxia. Comparing with normoxia, the A values of PASMCs exposed to hypoxia increased after 12 hours ( P lt;0. 05) , significantly increased after 24 hours ( P lt;0. 01) . Compared with 2 hours’exposure to hypoxia, the A values increased after 12 hours( P lt; 0. 05) , markedly increased after 24 hours ( P lt; 0. 01 ) , which after 48 hours was similar with 24 hours. The result of PCNA immunohistochemistry was consistent with that of MTT. Conclusions The tissue explants adherent method is simple and convenient, and can easily obtain rat PASMCs with high purity and stability. Hypoxia canpromote the proliferation of PASMCs.
Objective To explore the effect of hydrostatic pressure on intracellular free calcium concentration ([Ca2+]i) and the gene expression of transient receptor potential vanilloid (TRPV) in cultured human bladder smooth muscle cells (hb-SMCs), and to prel iminarily probe into the possible molecular mechanism of hb-SMCs prol iferation stimulated by hydrostatic pressure. Methods The passage 6-7 hb-SMCs were loaded with Ca2+ indicator Fluo-3/AM. When the hb-SMCs were under 0 cm H2O (1 cm H2O=0.098 kPa) (group A) or 200 cm H2O hydrostatic pressure for 30 minutes (group B) and then removing the 200 cm H2O hydrostatic pressure (group C), the [Ca2+]i was measured respectively by inverted laser anningconfocal microscope. When the hb-SMCs were given the 200 cm H2O hydrostatic pressure for 0 hour, 2 hours, 6 hours, 2 hours, and 24 hours, the mRNA expressions of TRPV1, TRPV2, and TRPV4 were detected by RT-PCR technique. Results The [Ca2+]i of group A, group B, and group C were (100.808 ± 1.724), (122.008 ± 1.575), and (99.918 ± 0.887) U, respectively; group B was significantly higher than groups A and C (P lt; 0.001). The [Ca2+]i of group C decreased to the base l ine level of group A after removing the pressure (t=0.919, P=0.394). The TRPV1, TRPV2, and TRPV4 genes expressed in hb-SMCs under 200 cm H2O hydrostatic pressure at 0 hour, 2 hours, 6 hours, 12 hours, and 24 hours, but the expressions had no obvious changes with time. There was no significant difference in the expressions of TRPV1, TRPV2, and TRPV4 among 3 groups (P gt; 0.05). Conclusion The [Ca2+]i of hb-SMCs increases significantly under high hydrostatic pressure. As possible genes in stretch-activated cation channel, the TRPV1, TRPV2, and TRPV4 express in hb-SMCs under 200 cm H2O hydrostatic pressure. It is possible that the mechanical pressure regulates the [Ca2+]i of hb-SMCs by opening the stretch-activated cation channel rather than up-regulating its expression.
Previous studies have shown that growth arrest, dedifferentiation, and loss of original function occur in cells after multiple generations of culture, which are attributed to the lack of stress stimulation. To investigate the effects of multi-modal biomimetic stress (MMBS) on the biological function of human bladder smooth muscle cells (HBSMCs), a MMBS culture system was established to simulate the stress environment suffered by the bladder, and HBSMCs were loaded with different biomimetic stress for 24 h. Then, cell growth, proliferation and functional differentiation were detected. The results showed that MMBS promoted the growth and proliferation of HBSMCs, and 80 cm H2O pressure with 4% stretch stress were the most effective in promoting the growth and proliferation of HBSMCs and the expression level of α-smooth muscle actin and smooth muscle protein 22-α. These results suggest that the MMBS culture system will be beneficial in regulating the growth and functional differentiation of HBSMCs in the construction of tissue engineered bladder.
ObjectiveTo investigate the effect of ADAM33 gene silencing in VSMCs on the proliferation and lumen formation of airway vascular endothelial cells (VECs) in a co-culture system and the possible regulatory mechanism. MethodsThe Human aortic smooth muscle cells (HASMCs) and human pulmonary microvascular endothelial cells (HPMECs) were used to construct a cell co-culture system. ADAM33 gene expression was silenced by lentivirus transfection technique, and the subjects were divided into endothelial cell blank group, co-culture group, co-culture +shRNA negative control group, and co-culture + ADAM33-SHRNA group. The expressions of sADAM33, VEGFA,VEGER2, ang-1 and ang-2 in co-culture system were detected by ELISA. The proliferation and lumen formation of HPMECs were observed by CCK-8 and Transwell experiments. The protein expression of Tie2, PI3K, Akt, and mTOR key molecules in Tie2/PI3K/Akt/mTOR signaling pathway and the phosphorylation levels of AKT and mTOR were detected by Western-blotting method. Results① Compared with the co-culture group (0.851±0.036) and the co-culture + shRNA negative control group (0.828±0.047), the OD value of the co-culture + ADAM33shRNA group (0.699±0.038) was significantly decreased (P<0.05). ② Compared with the co-culture group (159.169±15.740) and the co-culture +shRNA negative control group (157.357±21.612), the tube length of the co-culture +ADAM33shRNA group (120.812±2.791) was also significantly decreased (P<0.05). ③ After ADAM33 gene expression of HASMCs was silted in co-culture system, the expression levels of VEGFA, VEGFR2, ang-1 and ang-2 were significantly decreased (P<0.05), while the expression levels of Tie2, PI3K, P-Akt and P-mtor were decreased (P<0.05). ConclusionsSilencing the expression of the ADAM33 gene could reduce the release of sADAM33 from the membrane of the airway VSMCs, regulate the proliferation and lumen formation of airway VECs by reducing the expression of VEGF/VEGFR and inhibiting the activities of the Tie2/PI3K/Akt/mTOR signaling pathways,and then participate in airway vascular remodeling in asthma.
This study aimed to evaluate the effect of sanguinarine on biomechanical properties of rat airway smooth muscle cells (rASMCs) including stiffness, traction force and cytoskeletal stress fiber organization. To do so, rASMCs cultured in vitro were treated with sanguinarine solution at different concentrations (0.005~5 μmol/L) for 12 h, 24 h, 36 h, and 48 h, respectively. Subsequently, the cells were tested for their viability, stiffness, traction force, migration and microfilament distribution by using methylthiazolyldiphenyl-tetrazolium bromide assay, optical magnetic twisting cytometry, Fourier transform traction microscopy, scratch wound healing method, and immunofluorescence microscopy, respectively. The results showed that at concentration below 0.5 μmol/L sanguinarine had no effect on cell viability, but caused dose and time dependent effect on cell biomechanics. Specifically, rASMCs treated with sanguinarine at 0.05 μmol/L and 0.5 μmol/L for 12 and 24 h exhibited significant reduction in stiffness, traction force and migration speed, together with disorganization of the cytoskeletal stress fibers. Considering the essential role of airway smooth muscle cells (ASMCs) biomechanics in the airway hyperresponsiveness (AHR) of asthma, these findings suggest that sanguinarine may ameliorate AHR via alteration of ASMCs biomechanical properties, thus providing a novel approach for asthma drug development.
ObjectiveTo explore the relationship between the pressure level within the scope of promoting proliferation and cell injury of human bladder smooth muscle cells (HBSMCs). MethodHBSMCs in vitro were divided into the experimental group and control group. The cells in the experimental group were exposed to 40 cm H2O (1 cm H2O=0.098 kPa) pressure and those in the control group were cultured in normal condition for 24 hours. We investigated the cell morphology and cytoskeleton with indirect immunofluorescence staining for α-actin. Propidium iodide (PI) staining was applied to evaluate the level of cell apoptosis. ResultsThere was no significant difference in the cell morphology between the two groups. However, the expression of α-actin in the experimental group[(50.93±1.99)%] was significantly reduced comparing with that in the control group[(24.70±1.61)%] (t=32.404, P<0.001). The results of PI staining showed that compared with the control group[(3.50±2.12)%], the number of PI staining positive cells in the experimental group [(9.00±1.41)%] was significantly higher (t=6.110, P<0.001). ConclusionsPressure condition can promotes cell proliferation, but at the same time, it can also lead to cell injury of HBSMCs.
Objective To investigate the effects of simvastatin on the collagen synthesis of rat pulmonary arterial smooth muscle cells ( PASMCs ) induced by hypoxia. Methods Under hypoxic condition, rat PASMCs were cultured with different concentrations of simvastatin. Collagen synthesis of PASMCs with or without simvastatin were measured by 3H-proline incorporation assay. The mRNA expression of TGF-β1 and the contents of super oxide dismrtase ( SOD) ,malondialdehyde ( MDA) in mediumwere also measured. Results The incorporation data of 3H-TdR in the hypoxia group was significantly increased as compared with that in the control group ( P lt;0. 01) , and simvastatin significantly reduced the incorporation data of 3H-TdR induced by hypoxia. The expression of TGF-β1 mRNA in the hypoxia group was significantly increased as compared with that in the control group ( P lt; 0. 01 ) , and simvastatin could significantly inhibited hypoxia-induced expression of TGF-β1 mRNA in a dose-dependent manner. Compared with the hypoxia group, the expression of TGF-β1 mRNA decreased by 55% in simvastatin( 10 - 6mol /L) group ( P lt; 0. 01) , and by 70% ( P lt; 0. 01) in simvastatin ( 10 - 5mol /L) group. Compared with the control group, the activity of SOD was reduced and the contents of MDA were increased significantly in the hypoxia group. Simvastatin can increase the activity of SOD and reduced the content of MDA in a dose-dependent manner. Conclusions Simvastatin can decreases collagen synthesis of PASMCs. This effect might be explained that simvastatin can reduce lipid peroxide and expression of TGF-β1 mRNA.
Objective To observe whether umbilical cord mesenchymal stem cells (UCMSCs) can differentiate into the smooth muscle cells (SMCs) induced by bladder SMCs (BSMCs) conditioned medium so as to seek an alternative seed cells for the repair and reconstruction of the urology system. Methods UCMSCs and BSMCs were harvested from umbilical cord of full-term births and bladder tissues which were obtained from patients who underwent a radical cystectomy. BSMCs conditioned medium was prepared by mixing supernatant of BSMCs at passages 1-5 with complete medium at ratio of 1 ∶ 1. UCMSCs at passage 3 were cultured with BSMCs conditioned medium (induced group, group A) and complete medium (control group, group B), respectively; simple BSMCs served as positive control group (group C). The morphological changes of co-cultured UCMSCs were observed by inverted phase microscope, the expressions of α-smooth muscle actin (α-SMA), Calponin, and smooth muscle myosin heavy chain (SM-MHC) of UCMSCs were tested by immunofluorescence staining and Western blot at 7 and 14 days. Results The morphology of UCMSCs in group A started to change from a polygonal and short spindle shape to a large and spindle shape after co-culture, which was similar to BSMCs morphology; but the morphology of UCMSCs did not change obviously in group B. Immunofluorescence staining showed that the expressions of α-SMA, Calponin, and SM-MHC were positive in group C. At 7 days, the expression of α-SMA could be observed in groups A and B; at 14 days, the positive expression of α-SMA increased gradually in group A, but it did not increase in group B. At 7 days, a positive expression of Calponin could be observed in group A, and positive expression increased obviously at 14 days; the expression of Calponin could not be observed at 7 and 14 days in group B. However, the expression of SM-MHC could not be observed in groups A and B. The results of Western blot showed the expressions of α-SMA, Calponin, and SM-MHC protein were consistent with the results of immunofluorescence staining. Conclusion UCMSCs have the potential of differentiation into SMCs and may be a potential seed cells for bladder tissue engineering.
Objective To explore the activity of Ca2 + -activated K+ ( KCa) inairwaysmoothmuscle cells( ASMCs) in a rat model of chronic obstructive pulmonary disease( COPD) , and to observe the effect of 11, 12-Epoxyeicosatrienoic acid( 11, 12-EETs) on the KCa channel of ASMCs. Methods Forty male Sprague-Dawley rats were randomly assigned to a COPD group and a normal control group. The rats in the COPD group were exposed to cigarette smoking in a relatively closed chamber to induce COPD. The ASMCs were isolated from small bronchi using an acute enzymatic digestion method. In the symmetrical high K+ solution,the KCa currents were separated with inside-out configuration using the patch clamp technique. The activity of KCa currents in ASMCs between the COPD group and the normal group were compared and the effect of 11, 12-EETs on KCa channel was recorded. The opening probability( Po) , opening time( To) and closing time ( Tc) of the KCa were measured. Results Compared with the normal group, Po of KCa in the COPD rats was much shorter ( 0. 084 ±0. 028 vs 0. 198 ±0. 029, P lt; 0. 01) , To was shorter [ ( 0. 732 ±0. 058) ms vs ( 1. 648 ±0. 152) ms, P lt; 0. 01] and Tc was longer[ ( 12. 259 ±2. 612) ms vs ( 6. 753 ±1. 237) ms, P lt;0. 01] . 11, 12-EETs can evoke the activity of KCa currents of ASMCs in the COPD rats while Po was increased( 0. 227 ±0. 059 vs 0. 084 ±0. 028, P lt; 0. 01) , To was much longer[ ( 2. 068 ±0. 064) ms vs ( 0. 732 ±0. 058) ms, P lt; 0. 01] , and Tc was shorter [ ( 4. 273 ±0. 978) ms vs ( 12. 259 ±2. 612) ms, P lt;0. 01] .Conclusions The results suggest that the decreasing of KCa activity plays an important role in the development of COPD. 11,12-EETs can directly evoke the activity of KCa channel in COPD rats, thus relax the airway smooth muscles.