Suspension-induced murine keratinocyte differentiation is mediated by calcium

Luowei Li, Tamar Tennenbaum, Stuart H. Yuspa

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29 Scopus citations


Modulating extracellular Ca2+ (Ca(o)) and suspension culture are two frequently used methods to induce maturation of cultured human and mouse keratinocytes. To determine if the two methods share a common mechanism, changes in Ca2+ metabolism were studied in suspension cultures of mouse keratinocytes. Spontaneously detached and suspension-cultured keratinocytes in 0.05 mM Ca2+ medium express markers of suprabasal differentiation, while 0.05 mM Ca2+ is not permissive for marker expression by attached keratinocytes. Intracellular free Ca2+ (Ca(i)) increased rapidly after placing keratinocytes in suspension in 0.05 mM Ca2+, reaching levels up to 3-to 4-fold higher than Ca(i) in attached cells after 4-5 h. In suspended cells, the increase in Ca(i) was associated with a 2- to 6-fold increase in Ca2+ transport across plasma membrane as well as depletion of intracellular Ca2+-stores. Differentiation marker,expression and terminal differentiation were inhibited in suspension-cultured keratinocytes by preventing the rise of Ca(i) using either 1,2-bis(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid to chelate intracellular Ca2+ or ethyleneglycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid to reduce Ca(o). Together, these results indicate that a rise in Ca(i) is a common mechanism controlling differentiation in cultured mouse keratinocytes, and suspension of keratinocytes enhances Ca2+ transport and alters intracellular Ca2+ sequestration producing a rise in Ca(i).

Original languageEnglish
Pages (from-to)254-260
Number of pages7
JournalJournal of Investigative Dermatology
Issue number2
StatePublished - Feb 1996
Externally publishedYes


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