title: Chondroitin sulfate-E fine-tunes osteoblast differentiation via ERK1/2, Smad3 and Smad1/5/8 signaling by binding to N-cadherin and cadherin-11.
abstract: Bone formation in the vertebrate skeleton occurs via the processes of endochondral and membranous ossification. Bone matrices contain chondroitin sulfate (CS) chains that regulate endochondral ossification. However, the function of CS in membranous ossification is unclear. Here, using preosteoblastic MC3T3-E1 cells we demonstrate that chondroitin sulfate-E (CS-E) promotes osteoblast differentiation by binding to both N-cadherin and cadherin-11. Differentiated MC3T3-E1 cells exhibited an increase in the total amount of CS and of E-disaccharide units of CS over time. In addition, CS-E polysaccharide, but not CS-A polysaccharide, bound to N-cadherin and cadherin-11 and enhanced osteoblast differentiation. In contrast, osteoblast differentiation was inhibited in chondroitinase ABC-digested MC3T3-E1 cells. Notably, CS-E polysaccharide and hexasaccharide activated intracellular signaling during osteoblast differentiation in non-contacting MC3T3-E1 cells, decreased ERK1/2 phosphorylation, and activated Smad3 and Smad1/5/8; these reactions were blocked by neutralizing antibodies against N-cadherin or cadherin-11, even though cell-cell adhesion is reported to be required for initiation of MC3T3-E1 cell differentiation. Furthermore, CS-E-unit overexpression in MC3T3-E1 cells increased adhesion of the cells to N-cadherin and cadherin-11, and promoted osteoblast differentiation. Collectively, these results suggest that CS-E is a selective ligand for the potential CS receptors, N-cadherin and cadherin-11, leading to osteoblast differentiation of MC3T3-E1 cells.
authors.affiliation: Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan.
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Koike
authors.forename: Tomomi
authors.initials: T
authors.lastname: Izumikawa
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Tamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitagawa
mesh_terms: D015820:Cadherins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D002809:Chondroitin Sulfates / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D051898:Smad1 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D051902:Smad5 Protein / Q000378:metabolism; D051904:Smad8 Protein / Q000378:metabolism
chemical_list: D015820:Cadherins; D051898:Smad1 Protein; D051900:Smad3 Protein; D051902:Smad5 Protein; D051904:Smad8 Protein; C038142:chondroitin sulfate glycosaminoglycan; C086960:osteoblast cadherin; D002809:Chondroitin Sulfates; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3