Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Apoptosis is a process important for the development and homeostasis of self-renewing tissues, including bone. However, little is known about the function of Bcl-2, a key player of apoptosis, in the regulation of osteoblast activity. Ex vivo cultures of osteoblasts from Col2.3Bcl-2 mice, in which human Bcl-2 was targeted to bone by the 2.3 kb fragment of the type I collagen promoter, were used to study the effect of Bcl-2 in osteoblasts. During 35 days of culture, hBcl-2 expression increased without any effect on endogenous mouse Bcl-2 and Bax expression. Adhesion of transgenic (TG) osteoblasts was twofold more than that of wild-type (WT) cells, with significantly higher expression of integrins alpha(1), alpha(2), and alpha(5) but similar levels of alpha(v) and beta(1) relative to WT cells. Proliferation of osteoblasts was not affected. Overexpression of hBcl-2 promoted the differentiation of osteoblasts, as shown by increased message levels of alkaline phosphatase, type I collagen, bone sialoprotein, and osteocalcin in the TG compared to WT cells throughout the culture period. The two transcription factors essential for osteoblast differentiation, core binding factor alpha 1 (Cbfa-1) and osterix, had significantly higher expression in TG than WT cells during the early culture period. ss-Catenin, a central player in the canonical Wnt pathway, also had higher expression in TG than WT cultures. Mineralization was significantly decreased in TG cultures, with less osteoblast apoptosis, compared to WT. Thus, Bcl-2 seems to have multiple roles in modulating osteoblast activities.
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PMID:Bone-targeted overexpression of Bcl-2 increases osteoblast adhesion and differentiation and inhibits mineralization in vitro. 1730 93

Adhesion and spreading of cells on biomaterials are integrin-mediated processes. But recent findings indicate a key role of the cell membrane associated matrix substance hyaluronan (HA) in interface interactions. Because HA is a negatively charged molecule we assume that a biomaterial surface with an opposed charge could boost the first contact of the cell to the surface. Polished cp titanium (R(a)=0.19 microm) was coated with an amino-group containing plasma polymer (Ti PPA). For this purpose, a microwave excited, pulsed, low-pressure plasma was used. Additionally, collagen was immobilized on Ti PPA with polyethylene glycol diacid (PEG-DA), catalyzed by carbodiimide (CDI). The physico-chemical surface analytical techniques like XPS, FT-IR, water contact angle and zeta-potential verified the retention of the allylamine precursor structure. Human osteoblasts were cultured in serum-free Dulbecco's modified Eagle medium (DMEM). Adhesion and cell cycle phases were calculated by flow cytometry. Spreading and actin cytoskeleton were visualized by confocal microscopy. Gene expression of osteogenic markers was detected by real-time RT-PCR. Ti PPA is significantly advantageous concerning initial adhesion and spreading during the first hours of the cell contact to the surface. The proliferation of osteoblasts is positively influenced. Gene expression of the differentiation marker bone sialoprotein was upregulated after 24h. Our results demonstrate that functionalization of titanium with positively charged amino-groups is sufficiently enough to significantly improve initial steps of the cellular contact to the material surface.
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PMID:Improved initial osteoblast functions on amino-functionalized titanium surfaces. 1782 8

Adhesion peptides are currently used to enhance the interactions of osteoblasts with biomaterials. However, little is known about the effects of adhesion peptides on cell responses to growth factors, especially the bone morphogenetic proteins (BMPs). We used adhesion peptides Ac-CGGNGERPRGDTYRAY-NH(2) (pRGD), derived from bone sialoprotein, and Ac-CGGDGEA-NH(2) (pDGEA), derived from collagen, which interact with alpha(v)beta(3) and alpha(2)beta(1) integrins, respectively. We analyzed the effects of pRGD- and pDGEA-coated polystyrene (PS) on the responses of murine MC3T3-E1 preosteoblasts to a peptide derived from human BMP-9 (pBMP-9) in serum-free medium. After 1h, pRGD favoured interactions with alpha(v) while pDGEA bound beta(1) integrin subunits. Adding pBMP-9 (400 ng/mL) increased the amount of alpha(v) integrin subunits in cell membranes on pRGD-coated PS, but had no effect on beta(1) integrin subunits. Only on this substratum, collagen type I mRNA was enhanced and the addition of pBMP-9 promoted the early cell differentiation, increasing their alkaline phosphatase (ALP) activity within 24 h. These cells also organized beta(1) integrin subunits at their focal adhesion points. Inhibiting alpha(2)beta(1) integrins by pDGEA pre-treatment decreased this ALP activity. It is therefore important to understand the impact of adhesion peptides on the early cell responses to growth factors in order to improve biomimetic materials.
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PMID:Short-term effects of adhesion peptides on the responses of preosteoblasts to pBMP-9. 1802 75


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