title: GSK3b-inhibitor lithium chloride enhances activation of Wnt canonical signaling and osteoblast differentiation on hydrophilic titanium surfaces.
abstract: OBJECTIVE
  Promoting bone formation at the tissue interface is an important step to improve implant success. This study investigated whether stimulation of Wnt signaling by GSK3b inhibitor lithium chloride (LiCl) could affect the response of mesenchymal or osteoblastic cells growing on titanium surfaces with different topography and wettability, and improve their differentiation along the osteoblastic lineage.
  
  
  METHODS
  Murine mesenchymal C2C12 cells were plated on Pickled, acid-etched/sand-blasted (SLA), and hydrophilic SLA titanium disks (modSLA) and stimulated with increasing doses of LiCl. Cell viability was measured using chemiluminescence-based ATP quantitation and activation of Wnt canonical signaling was measured using a Luciferase-based reporter assay. Gene expression was measured using real time PCR in C2C12 cells, murine osteoblastic MC3T3 cells or murine primary bone marrow cells.
  
  
  RESULTS
  LiCl stimulated Wnt activation and expression of Wnt markers in C2C12 cells on modSLA. Addition of 1 mM LiCl increased levels for bone marker Osteocalcin in MC3T3 cells on modSLA surfaces. Similarly, LiCl potently enhanced Osteoprotegetrin levels in MC3T3 cells on modSLA. When primary bone marrow cells were stimulated with LiCl, the expression of Wnttarget genes and osteoblastic differentiation markers was increased on modSLA surfaces.
  
  
  CONCLUSIONS
  Stimulation of the canonical Wnt pathway promoted osteoblast differentiation on hydrophilic modSLA surfaces. Taken together, these results demonstrate that Wnt activators such as LiCl should be further tested as a possible approach to improve implant osseointegration.
authors.affiliation: Sez. Odontostomatologia, University of Parma, Parma, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Galli
authors.forename: M
authors.initials: M
authors.lastname: Piemontese
authors.forename: S
authors.initials: S
authors.lastname: Lumetti
authors.forename: E
authors.initials: E
authors.lastname: Manfredi
authors.forename: G M
authors.initials: GM
authors.lastname: Macaluso
authors.forename: G
authors.initials: G
authors.lastname: Passeri
mesh_terms: D016475:3T3 Cells; D000134:Acid Etching, Dental / Q000379:methods; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D019070:Cell Lineage / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors*; D000071679:Glycogen Synthase Kinase 3 beta; D057927:Hydrophobic and Hydrophilic Interactions; D018021:Lithium Chloride / Q000494:pharmacology*; D008156:Luciferases; D049449:Luminescence; D049408:Luminescent Agents; D051379:Mice; D032342:Muscle Cells / Q000187:drug effects; D010006:Osteoblasts / Q000187:drug effects*; D015675:Osteocalcin / Q000187:drug effects; D053244:Osteoprotegerin / Q000187:drug effects; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D017155:Wettability; D060449:Wnt Signaling Pathway / Q000187:drug effects*
chemical_list: D003764:Dental Materials; D049408:Luminescent Agents; D053244:Osteoprotegerin; C506031:Tnfrsf11b protein, mouse; D015675:Osteocalcin; D014025:Titanium; D008156:Luciferases; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3; D000469:Alkaline Phosphatase; D018021:Lithium Chloride