Altering sphingolipid composition with aging induces contractile dysfunction of gastric smooth muscle via KCa1.1 upregulation

Shinkyu Choi, Ji Aee Kim, Tae Hun Kim, Hai yan Li, Kyong Oh Shin, Yong Moon Lee, Seikwan Oh, Yael Pewzner-Jung, Anthony H. Futerman, Suk Hyo Suh

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


KCa1.1 regulates smooth muscle contractility by modulating membrane potential, and age-associated changes in KCa1.1 expression may contribute to the development of motility disorders of the gastrointestinal tract. Sphingolipids (SLs) are important structural components of cellular membranes whose altered composition may affect KCa1.1 expression. Thus, in this study, we examined whether altered SL composition due to aging may affect the contractility of gastric smooth muscle (GSM). We studied changes in ceramide synthases (CerS) and SL levels in the GSM of mice of varying ages and compared them with those in young CerS2-null mice. The levels of C16- and C18-ceramides, sphinganine, sphingosine, and sphingosine 1-phosphate were increased, and levels of C22, C24:1 and C24 ceramides were decreased in the GSM of both aged wild-type and young CerS2-null mice. The altered SL composition upregulated KCa1.1 and increased KCa1.1 currents, while no change was observed in KCa1.1 channel activity. The upregulation of KCa1.1 impaired intracellular Ca2+ mobilization and decreased phosphorylated myosin light chain levels, causing GSM contractile dysfunction. Additionally, phosphoinositide 3-kinase, protein kinase Cζ, c-Jun N-terminal kinases, and nuclear factor kappa-B were found to be involved in KCa1.1 upregulation. Our findings suggest that age-associated changes in SL composition or CerS2 ablation upregulate KCa1.1 via the phosphoinositide 3-kinase/protein kinase Cζ/c-Jun N-terminal kinases/nuclear factor kappa-B-mediated pathway and impair Ca2+ mobilization, which thereby induces the contractile dysfunction of GSM. CerS2-null mice exhibited similar effects to aged wild-type mice; therefore, CerS2-null mouse models may be utilized for investigating the pathogenesis of aging-associated motility disorders.

Original languageEnglish
Pages (from-to)982-994
Number of pages13
JournalAging Cell
Issue number6
StatePublished - 1 Dec 2015

Bibliographical note

Publisher Copyright:
© 2015 The Anatomical Society and John Wiley & Sons Ltd.


  • Aging
  • Ca-activated K channel
  • Ceramide synthases
  • Contractile dysfunction
  • Smooth muscle
  • Sphingolipids


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