These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Strontium induces murine keratinocyte differentiation in vitro in the presence of serum and calcium.
    Author: Li L, Kruszewski FH, Punnonen K, Tucker RW, Yuspa SH, Hennings H.
    Journal: J Cell Physiol; 1993 Mar; 154(3):643-53. PubMed ID: 7679679.
    Abstract:
    Primary mouse keratinocytes in culture are induced to terminally differentiate by increasing extracellular Ca2+ concentrations (Cao) from 0.05 mM to > or = 0.1 mM. The addition of Sr2+ (> or = 2.5 mM) to medium containing 0.05 mM Ca2+ induces focal stratification and terminal differentiation, which are similar to that found after increasing the Cao to 0.12 mM. Sr2+ in 0.05 mM Ca2+ medium induces the expression of the differentiation-specific keratins, keratin 1 (K1), keratin 10 (K10), and the granular cell marker, filaggrin, as determined by both immunoblotting and immunofluorescence. Sr2+ induces the expression of those differentiation markers in a dose dependent manner, with an optimal concentration of 5 mM. In the absence of Ca2+ in the medium, the Sr2+ effects are reduced, and Sr2+ is ineffective when both Ca2+ and serum are deleted from the medium. Sr2+ treatment increases the ratio of fluorescence intensity of the intracellular Ca2+ sensitive probe, fura-2, indicating an associated rise in the level of intracellular free Ca2+ and/or Sr2+. At doses sufficient to induce differentiation, Sr2+ also increases the level of inositol phosphates in primary keratinocytes within 30 min. The uptake curves of 85Sr2+ by primary keratinocytes are similar to those of 45Ca2+. At low concentrations, the initial uptake of both 45Ca2+ and 85Sr2+ reaches a plateau within 1 hr; at higher concentrations, the uptake of both 45Ca2+ and 85Sr2+ increases continuously for 12 hr. In keratinocytes pre-equilibrated with 45Ca2+ in 0.05 mM Ca2+ medium, Sr2+ causes an increase of 45Ca2+ uptake, which is dependent on the presence of serum. These results suggest that Sr2+ utilizes the same signalling pathway as Ca2+ to induce keratinocyte terminal differentiation and that Ca2+ may be required to exert these effects.
    [Abstract] [Full Text] [Related] [New Search]