title: Enhanced insulin secretion from engineered 3T3-L1 preadipocytes by induction of cellular differentiation.
abstract: We have established insulin-secreting cell line, L1-INS/fur cells, by engineering 3T3-L1 murine preadipocytes with human preproinsulin cDNA. Analysis with HPLC, mass spectrometry and immunological assay identified human insulin in the culture medium. Notably, secretion of insulin from L1-INS/fur cell was increased 8.2 times higher after induction of cellular differentiation. The increment of insulin secretion during differentiation was further enhanced by additive treatment with thiazolidinedione, a promoting agent of adipocyte differentiation. This observation strongly suggests that the enhancement of insulin secretion is tightly associated with cellular differentiation process itself. Expression rate of the insulin transgene was not changed after the additional treatment with thiazolidinedione. On the other hand, furin gene expression by Northern analysis showed an increase, and Western analysis revealed even more reduction in cellular content of proinsulin. These results indicate that mechanism of the observed enhancement in insulin secretion during the differentiation is mainly due to increased capacity of the proinsulin processing by induction of furin. Results of our present study will provide important information on cell-based therapy using undifferentiated progenitors and tissue stem cells.
authors.affiliation: Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Masami
authors.initials: M
authors.lastname: Nemoto
authors.forename: Nozomu
authors.initials: N
authors.lastname: Nakai
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sakai
authors.forename: Koichiro
authors.initials: K
authors.lastname: Yamasaki
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Hiki
authors.forename: Toya
authors.initials: T
authors.lastname: Ohashi
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Eto
authors.forename: Naoko
authors.initials: N
authors.lastname: Tajima
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000502:physiology / Q000637:transplantation*; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000628:therapy*; D045683:Furin / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D011384:Proinsulin / Q000235:genetics / Q000378:metabolism*; D023822:Tissue Engineering
chemical_list: D011384:Proinsulin; D045683:Furin
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