[show abstract][hide abstract] ABSTRACT: We established an in vitro culture system which mimicked the differentiation pathway of smooth muscle cell, using TBR-B, a bone marrow stromal cell line derived from transgenic mice harboring temperature-sensitive SV40 large T-antigen gene. TBR-B cells have the potential to express smooth muscle-specific genes including h1-calponin, h-caldesmon, SM22alpha and alpha-actin, only after cultured in the differentiation medium for 2 weeks. The differentiation state of TBR-B was well controlled by using different culture medium. Using this cell line, we also found that ascorbic acid is a potent factor inducing the expression of h1-calponin and alpha-actin. TBR-B cells will serve as a useful tool for elucidating the regulatory mechanisms of smooth muscle-specific gene expression, and for identifying compounds that regulate the differentiation state of vascular smooth muscle cells.
[show abstract][hide abstract] ABSTRACT: The linkage between inositol 1,4,5-trisphosphate (IP(3)) receptors (IP(3)Rs) and cytoskeletal proteins is considered to be important in cell function. In the present study, the association of IP(3)R subtypes with cytoskeletal proteins was examined using monoclonal antibodies specific to each IP(3)R subtype. We found that IP(3)R type 2 colocalized with talin, a focal contact cytoskeletal protein. IP(3)R type 2 exhibited a patchy distribution in the peripheral cytoplasm differently from type 1 and type 3 IP(3)R. Furthermore, IP(3)R subtypes co-immunoprecipitated with talin, vinculin and alpha-actin, but not alpha-actinin or paxillin.
[show abstract][hide abstract] ABSTRACT: Proliferation of smooth muscle cells (SMC) has a role in the development of cardiovascular diseases. We investigated the alteration of contractile signals in proliferating SMC by measuring the increase in intracellular [Ca(2+)] to endothelin-1 (ET-1), noradrenaline (NA), or angiotensin II (AgII). We found that the increase in intracellular [Ca(2+)] by NA or ET-1 decreased in proliferating SMC in comparison to growth-arrested SMC. The increase in intracellular [Ca(2+)] by AgII was stable between the cells. Immunoblotting of inositol 1,4,5-trisphosphate receptors (IP(3)Rs) which are responsible for the mobilization of Ca(2+) by those vasoactive substances revealed that expression of IP(3)R type 1 and type 2 was decreased. Expression of IP(3)R type 3 was increased. The altered Ca(2+) signaling by the cell growth might involve the expression of IP(3)R subtypes.
Biochemical and Biophysical Research Communications 12/1999; 264(3):774-6. · 2.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: We have established novel vascular smooth muscle cell lines (SVS30 and SVS24 cells) which retain the expression of specific markers for smooth muscle cells, such as alpha-actin, smooth muscle myosin heavy chain-1, and calponin, from transgenic mice harboring the temperature-sensitive SV40 large T-antigen gene. SVS cell lines showed temperature-dependent growth and the expression of SV40 large T-antigen. Interestingly, protein and mRNA levels of smooth muscle myosin heavy chain-1 and calponin seen in culture at the non-permissive temperature (39 degrees C) were higher than those at the permissive temperature (33 degrees C). These results suggest that SV40 large T-antigen affects the expression of smooth muscle-specific markers in SVS cell lines, and that some of the characters in SVS cell lines can be controlled by culture temperature. SVS cell lines should be quite valuable tools with which to study the regulation of phenotypic modulation of smooth muscle cells, and to identify smooth muscle specific transcription factors which involve the expression of smooth muscle myosin heavy chain-1 and calponin genes.
Journal of Molecular and Cellular Cardiology 09/1997; 29(8):2177-86. · 5.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: The nucleotide and deduced amino acid sequences of two isoforms of mouse smooth-muscle myosin heavy chain (SM1 and SM2) were determined. SM1 (6175 bp) and SM2 (6214 bp) cDNA contained a single open reading frame that encodes 1972 and 1938 amino acids (227,056 Da and 223,294 Da), respectively. Smooth muscle myosin heavy chain mRNA was expressed highly in smooth muscle tissue (small intestine) and weakly in heart and lung. Each of SM1 and SM2 cDNA was transfected and expressed in CHO cells. The expressed myosin heavy chains were detected with an antibody raised against smooth muscle myosin heavy chains and showed the same mobility as the native smooth muscle myosin heavy chains in SDS-PAGE.
Biochemical and Biophysical Research Communications 04/1997; 232(2):313-6. · 2.41 Impact Factor