Exogenous insulin stimulates glycogen accumulation in Rhipicephalus (Boophilus) microplus embryo cell line BME26 via PI3K/AKT pathway.
Ticks are obligatory blood-feeding arthropods and important vectors of both human and animal disease agents. Besides its metabolic role, insulin signaling pathway (ISP) is widely described as crucial for vertebrate and invertebrate embryogenesis, development and cell survival. In such cascade, Phosphatidylinositol 3-OH Kinase (PI3K) is hierarchically located upstream Protein Kinase B (PKB). To study the insulin-triggered pathway and its possible roles during embryogenesis we used a culture of embryonic Rhipicephalus microplus cells (BME26). Exogenous insulin elevated cell glycogen content in the absence of fetal calf serum (FCS) when compared to cells without treatment. Moreover, in the presence of PI3K inhibitors (Wortmannin or LY294002) these effects were blocked. We observed an increase in the relative expression level of PI3K's regulatory subunit (p85), as determined by qRT-PCR. In the presence of PI3K inhibitors these effects on transcription were also reversed. Additionally, treatment with Wortmannin increased the expression level of the insulin-regulated downstream target glycogen synthase kinase 3 beta (GSK3beta). The p85 subunit showed elevated transcription levels in ovaries from fully engorged females, but was differentially expressed during tick embryogenesis. These results strongly suggest the presence of an insulin responsive machinery in BME26 cells, and its correlation with carbohydrate/glycogen metabolism also during embryogenesis.
de Abreu
Leonardo Araujo
LA
Laboratório de Química e Função de Proteínas e Peptídeos, CBB, Universidade Estadual Norte Fluminense, 28013-620, Campos dos Goytacazes, RJ, Brazil.
Fabres
Arianne
A
Esteves
Eliane
E
Masuda
Aoi
A
da Silva Vaz
Itabajara
I
Daffre
Sirlei
S
Logullo
Carlos
C
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002867:Chromones / Q000494:pharmacology; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005260:Female; D006003:Glycogen / Q000378:metabolism*; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D007328:Insulin / Q000494:pharmacology*; D009025:Morpholines / Q000494:pharmacology; D010053:Ovary / Q000254:growth & development / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D048494:Rhipicephalus / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D000077191:Wortmannin
D000730:Androstadienes; D002867:Chromones; D006003:Glycogen; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D007328:Insulin; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C000605506:GSK3B protein, human