title: Phosphodiesterase 3 and 4 comprise the major cAMP metabolizing enzymes responsible for insulin secretion in INS-1 (832/13) cells and rat islets.
abstract: cAMP is a key modulator for glucose-dependent insulin secretion (GDIS). Members of the phosphodiesterase (PDEs) gene family regulate intracellular levels of cAMP by hydrolyzing cAMP to the corresponding inactive 5'AMP derivative. These studies examined the expression and function of all 18 cAMP-specific PDEs in the rat insulinoma derived INS-1 (832/13) cell and isolated rat islets using quantitative PCR and siRNA-mediated gene-specific knockdown. PDE1C, PDE3B, PDE4C, PDE8B, PDE10A, and PDE11A were significantly expressed in rat islets and INS-1 (832/13) cells at the mRNA level. PDE1C, PDE10A and PDE11A were also expressed in brain, along with PDE3B, PDE4C and PDE8B which were also highly expressed in liver, and PDE3B was present in adipose tissue and PDE4C in skeletal muscle. siRNA mediated knockdown of PDE1C, PDE3B, PDE8B and PDE4C, but not PDE10A and PDE11A, significantly enhanced GDIS in rat INS-1 (832/13) cells. Also, selective inhibitors of PDE3 (trequinsin) and PDE4 (roflumilast and L-826,141) significantly augmented GDIS in both INS-1 (832/13) cells and rat islets. The combination of PDE3 and PDE4 selective inhibitors demonstrate that these enzymes comprise a significant proportion of the cAMP metabolizing activity in INS-1 cells and rat islets.
authors.affiliation: Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Kirkland, Quebec, Canada.
authors.forename: Deena
authors.initials: D
authors.lastname: Waddleton
authors.forename: Weizhen
authors.initials: W
authors.lastname: Wu
authors.forename: Yue
authors.initials: Y
authors.lastname: Feng
authors.forename: Chris
authors.initials: C
authors.lastname: Thompson
authors.forename: Michael
authors.initials: M
authors.lastname: Wu
authors.forename: Yun-Ping
authors.initials: YP
authors.lastname: Zhou
authors.forename: Andrew
authors.initials: A
authors.lastname: Howard
authors.forename: Nancy
authors.initials: N
authors.lastname: Thornberry
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Mancini
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D000242:Cyclic AMP / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000201:enzymology*; D010727:Phosphoric Diester Hydrolases / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007328:Insulin; D012333:RNA, Messenger; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D005947:Glucose