CD44, a Cell Surface Chondroitin Sulfate Proteoglycan, Mediates Binding of Interferon-γ and Some of Its Biological Effects on Human Vascular Smooth Muscle Cells

Abstract It has been suggested that trimethylamine oxide (TMAO), a liver oxygenation product of gut bacteria-produced trimethylamine (TMA), is a marker of cardiovascular risk. However, mechanisms of the increase and biological effects of TMAO are obscure. Furthermore, the potential role of TMAO precursor, that is TMA, has not been investigated. We evaluated the effect of age, a cardiovascular risk factor, on plasma levels of TMA and TMAO, gut bacteria composition, gut-to-blood penetration of TMA, histological and hemodynamic parameters in 3-month-old and 18-month-old, male, Sprague–Dawley and Wistar–Kyoto rats. Cytotoxicity of TMA and TMAO was studied in human vascular smooth muscle cells. Older rats showed significantly different gut bacteria composition, a significantly higher gut-to-blood TMA penetration, and morphological and hemodynamic alterations in intestines. In vitro, TMA at concentration of 500 µmol/L (2-fold higher than in portal blood) decreased human vascular smooth muscle cells viability. In contrast, TMAO at 1,000-fold higher concentration than physiological one had no effect on human vascular smooth muscle cells viability. In conclusion, older rats show higher plasma level of TMA due to a “leaky gut”. TMA but not TMAO affects human vascular smooth muscle cells viability. We propose that TMA but not TMAO may be a marker and mediator of cardiovascular risk.

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Interaction of the NG2 chondroitin sulfate proteoglycan with type VI collagen.

The Journal of Cell Biology ◽

10.1083/jcb.111.6.3177 ◽

1990 ◽

Vol 111 (6) ◽

pp. 3177-3188 ◽

Cited By ~ 121

Author(s):

W B Stallcup ◽

K Dahlin ◽

P Healy

Keyword(s):

Cell Surface ◽

Chondroitin Sulfate ◽

Cell Lines ◽

Intervertebral Discs ◽

Chondroitin Sulfate Proteoglycan ◽

Cellular Interactions ◽

Sulfate Proteoglycan ◽

Type Vi Collagen ◽

Double Labeling ◽

Parallel Change

The NG2 chondroitin sulfate proteoglycan is a membrane-associated molecule of approximately 500 kD with a core glycoprotein of 300 kD. Both the complete proteoglycan and a smaller quantity of the 300-kD core are immunoprecipitable with polyclonal and monoclonal antibodies against purified NG2. From some cell lines, the antibodies coprecipitate NG2 and type VI collagen, the latter appearing on SDS-PAGE as components of 140 and 250 kD under reducing conditions. The immunoprecipitation of type VI collagen does not seem to be due to recognition of the collagen by the antibodies, but rather to binding of the collagen to NG2. Studies on the NG2-type VI collagen complex suggest that binding between the two molecules is mediated by protein-protein interactions rather than by ionic interactions involving the glycosaminoglycans. Immunofluorescence double labeling in frozen sections of embryonic rat shows that NG2 and type VI collagen are colocalized in structures such as the intervertebral discs and arteries of the spinal column. In vitro the two molecules are highly colocalized on the surface of several cell lines. Treatment of these cells resulting in a change in the distribution of NG2 on the cell surface also causes a parallel change in type VI collagen distribution. Our results suggest that cell surface NG2 may mediate cellular interactions with the extracellular matrix by binding to type VI collagen.

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Codistribution of heparan sulfate proteoglycan, laminin, and fibronectin in the extracellular matrix of normal rat kidney cells and their coordinate absence in transformed cells.

The Journal of Cell Biology ◽

10.1083/jcb.94.1.28 ◽

1982 ◽

Vol 94 (1) ◽

pp. 28-35 ◽

Cited By ~ 93

Author(s):

E G Hayman ◽

A Oldberg ◽

G R Martin ◽

E Ruoslahti

Keyword(s):

Cell Surface ◽

Heparan Sulfate ◽

Chondroitin Sulfate ◽

Rat Kidney ◽

Heparan Sulfate Proteoglycan ◽

Chondroitin Sulfate Proteoglycan ◽

Transformed Cells ◽

Kidney Cells ◽

Sulfate Proteoglycan ◽

Normal Rat

We used antibodies raised against both a heparan sulfate proteoglycan purified from a mouse sarcoma and a chondroitin sulfate proteoglycan purified from a rat yolk sac carcinoma to study the appearance and distribution of proteoglycans in cultured cells. Normal rat kidney cells displayed a fibrillar network of immunoreactive material at the cell surface when stained with antibodies to heparan sulfate proteoglycan, while virally transformed rat kidney cells lacked such a surface network. Antibodies to chondroitin sulfate proteoglycan revealed a punctate pattern on the surface of both cell types. The distribution of these two proteoglycans was compared to that of fibronectin by double-labeling immunofluorescent staining. The heparan sulfate proteoglycan was found to codistribute with fibronectin, and fibronectin and laminin gave coincidental stainings. The distribution of chondroitin sulfate proteoglycan was not coincidental with that of fibronectin. Distinct fibers containing fibronectin but lacking chondroitin sulfate proteoglycan were observed. When the transformed cells were cultured in the presence of sodium butyrate, their morphology changed, and fibronectin, laminin, and heparan sulfate proteoglycan appeared at the cell surface in a pattern resembling that of normal cells. These results suggest that fibronectin, laminin, and heparan sulfate proteoglycan may be complexed at the cell surface. The proteoglycan may play a central role in assembly of such complexes since heparan sulfate has been shown to interact with both fibronectin and laminin.

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