FIBROBLAST HETEROGENEITY OF SIGNAL-TRANSDUCTION MECHANISMS TO COMPLEMENT-C1Q - ANALYSES OF CALCIUM MOBILIZATION, INOSITOL PHOSPHATE ACCUMULATION, AND PROTEIN-KINASE-C REDISTRIBUTION

Citation
S. Bordin et al., FIBROBLAST HETEROGENEITY OF SIGNAL-TRANSDUCTION MECHANISMS TO COMPLEMENT-C1Q - ANALYSES OF CALCIUM MOBILIZATION, INOSITOL PHOSPHATE ACCUMULATION, AND PROTEIN-KINASE-C REDISTRIBUTION, Journal of periodontology, 69(6), 1998, pp. 642-649
Citations number
41
Categorie Soggetti
Dentistry,Oral Surgery & Medicine
Journal title
ISSN journal
00223492
Volume
69
Issue
6
Year of publication
1998
Pages
642 - 649
Database
ISI
SICI code
0022-3492(1998)69:6<642:FHOSMT>2.0.ZU;2-P
Abstract
FIBROBLASTS OF HEALTHY AND GRANULATION gingiva are phenotypically hete rogeneous with regard to binding Clq collagen-like (cClqR) or Clq glob ular-heads (gClqR) regions, respectively. Here, isolated fibroblast su bsets, expressing either the cClqR or the gClqR phenotype, were stimul ated with Clq, and assessed for changes in cytosolic free calcium [Ca2 +](i), accumulation of inositol trisphosphate (IP3), and redistributio n of Ca2+-dependent protein kinases-C (cPKCs) from cytosol to membrane s. Changes in [Ca2+], were determined using Indo-1 fluorescence in com bination with adhering cell analysis and sorting (ACAS) cytometry. Acc umulation of IP3 was quantified using a competitive radioreceptor bind ing assay. Redistribution of cPKCs was evaluated by immunoblotting wit h antibodies to PKC alpha/beta I-beta II/gamma. Subsets manifested dif ferent fluctuations in [Ca2+](i) levels 20 seconds after Clq-stimulati on in the presence of millimolar concentrations of external calcium. W hereas cClqR fibroblasts responded with a 38% over baseline [Ca2+](i) increase which was sustained for 20 to 30 minutes, gClqR fibroblasts r esponded with a higher (264% over baseline) and more rapid (2 to 3 min utes) transient. Likewise, subsets exhibited different kinetics of IP3 accumulation. Whereas cClqR fibroblasts responded with an IP3 increas e of 32 +/- 3 pmol/10(4) cells over baseline after 5 seconds stimulati on, gClqR fibroblasts responded after 15 to 20 seconds with a lower in crease (13 +/- 0.8 IP3 pmol/10(4) cells over baseline). Subsets differ ed in cPKCs redistribution which peaked in gClqR-membranes 30 seconds after stimulation and remained sustained between 10 and 30 minutes. No cPKC redistribution was detectable in stimulated cClqR-cells. We conc lude that fibroblasts are heterogeneous in phosphoinositide-Ca2+ signa ling and cPKC redistribution to Clq, and suggest that these difference s may affect activities of normal and granulation gingiva.