Objective To investigate whether calcitonin gene-related peptide(CGRP) can influence the proliferation and phenotypic modulation of vascular smooth muscle cells(VSMCs),and what is the relationship between them. Methods Vascular smooth muscle cells(VSMCs) were cultured respectively with rat aorta cultivated for 8 days in vitro and with normal aorta(not culture) through the explant-attached method,and CGRP was added into the culture medium of the experimental groups.The proliferation of cells was labeled by 5-bromodeoxyuridine(5-BrdU) with immunocytochemical method,and the mRNA expression of hypertension-related gene-1(HRG-1) and smooth muscle 22 alpha(SM22?) were determined by RT-PCR. Results The proliferating cells labeled by BrDU from the aorta cultured for 8 days in vitro were increased notablly and the mRNA expression of HRG-1 and SM22? were decreased.While the VSMCs were cultured in the culture medium containing CGRP,the proliferous cells labeled by BrdU were obviously decreased and the mRNA expression of HRG-1 and SM22? were significantly increased.Conclusion It is showed that CGRP could inhibit the proliferation of VSMCs and change the phenotype of VSMCs from synthesize to contractile type.It might be a good cellular model which provides a good experimental platform to research the proliferating vascular disease as well as its prevention and treatment.

ObjectiveTo study the influence of different culture conditions in vitro on phenotype, proliferation and cytoskeletal proteins expression of vascular smooth muscle cells(VSMCs). Methods The cultured VSMCs from rat aorta were divided into six groups: P2 control,P2 starvation,P4 control,P4 starvation,P6 control and P6 starvation. The proliferating cells were labeled by 5-bromodeoxyuridine (5-BrdU); The mRNA expression of smooth muscle 22 alpha (SM22α) was detected by reverse transcription-polymerase chain reaction method (RT-PCR); The cytoskeletal proteins including SMα-actin,β-Tubulin and Desmin were observed through immunohistochemical staining. Results With the increase of cell passage, cytoskeletal proteins expression of VSMCs decreased,cellular organs increased and secretory vesicles were abundant; in serum-free cultured cells mitochondria increased and electron density enhanced in cytoplasm of VSMCs.On the contrary the expression of SMα-actin decreased, and the expression of SMα-actin increased. The expression of β-Tublin and Desmin decreased more obviously, and at 6 passages failed to express. Conclusion The conditioned medium and serum-free had the different effects on the phenotype,proliferation and cytoskeleton of VSMCs in different passage, and there was internal relationship among them. The internal relationship played an important role in the maintaining of cell morphology, contractile function and vascular remodeling. The disappearance of expression of β-Tubulin and desmin might have important biological significance.

A mesophilic xylanase from Aspergillus oryzae, abbreviated to AoXyn11A, belongs to glycoside hydrolase family 11. Using AoXyn11A as the parent, the thermotolerant hybrid xylanase, we constructed AEx11A by substituting its N-terminus with the corresponding region of a hyperthermostable family 11 xylanase, EvXyn11(TS). AoXyn11A- and AEx11A-encoding genes were expressed in Pichia pastoris GS115 separately, and effects of temperatures on expressed products were determined and compared. The optimum temperature (T(opt)) of AEx11A was 75 degrees C and its half-life at 70 degrees C (t1/2(70)) was 197 min, improved as compared with those (T(opt) = 50 degrees C, t1/2(70) = 1.0 min) of AoXyn11A. Homology modeling of the AEx11A's structure and comparison between structures of AEx11A and AoXyn11A revealed that one disulfide bridge (Cys5-Cys32) was introduced into AEx11A resulted from N-terminus substitution. To explore the effect of the disulfide bridge on the thermostability of AEx11A, it was removed from AEx11A by site-directed mutagenesis (C5T). Analytical results show that the T(opt) of the mutant AEx11A (AEx11A(C5T)) dropped to 60 degrees C from 75 degrees C of AEx11A, and its t1/2(70) and t1/2(80) also decreased to 3.0 and 1.0 min from 197 and 25 min.
Amino Acid Sequence ; Amino Acid Substitution ; Aspergillus oryzae ; enzymology ; Base Sequence ; Disulfides ; chemistry ; metabolism ; Endo-1,4-beta Xylanases ; biosynthesis ; chemistry ; genetics ; Enzyme Stability ; genetics ; Molecular Sequence Data ; Mutagenesis, Site-Directed ; methods ; Pichia ; genetics ; metabolism ; Protein Engineering ; methods ; Recombinant Proteins ; biosynthesis ; chemistry ; genetics