Insulin and insulin-like growth factor-1 can modulate the phosphoinositide-3-kinase/Akt/FoxO1 pathway in SZ95 sebocytes in vitro. (5th November 2015)

• Record Type: Journal Article
• Authors: Mirdamadi, Yasaman; Thielitz, Anja; Wiede, Antje; Goihl, Alexander; Papakonstantinou, Eleni; Hartig, Roland; Zouboulis, Christos C.; Reinhold, Dirk; Simeoni, Luca; Bommhardt, Ursula; Quist, Sven; Gollnick, Harald
• Is Part Of: Molecular and cellular endocrinology. Volume 415(2015)
• Page Start: 32
• Page End: 44
• Publication Date: 2015-11-05
• Subjects: High glycaemic load diet -- Acne -- IGF-1 -- Insulin -- FoxO1 -- Sebocytes; ACS Acyl-CoA synthetase -- ANOVA analysis of variance -- AR androgen receptor -- DAPI 4, 6-diamidino-2-phenylindole, dihydro-chloride -- ECL Enhanced chemiluminescence -- FAS Fatty acid synthase -- FoxO1 forkhead box-O1 -- GH growth hormone -- HMGCR HMG-CoA reductase -- IGF-1 insulin-like growth factor-1 -- IGFBP-1 IGF binding protein-1 -- LXR liver X receptor -- P. acnes Propionibacterium acnes -- PBS Phosphate buffered saline -- PDGF platelet-driven growth factor -- PI3K phosphoinositide-3-kinase -- PFA paraformaldehyde -- PPAR-γ peroxisome proliferator-activated receptors -- RXR retinoid X receptor -- SCD stearoyl-CoA desaturase -- SQD Squalene epoxidase -- SREBP-1 sterol regulatory element binding protein-1 -- TLR Toll-like receptor; Endocrinology -- Periodicals; Molecular biology -- Periodicals; Cytology -- Periodicals; Endocrinology -- Periodicals; Hormones -- Periodicals; Endocrinologie -- Périodiques; Cytology; Endocrinology; Molecular biology; Periodicals; 573.4
• DOI: 10.1016/j.mce.2015.08.001
• Languages: English
• ISSNs: 0303-7207

Abstract

Abstract: A recent hypothesis suggests that a high glycaemic load diet-associated increase of insulin-like growth factor-1 (IGF-1) and insulin may promote acne by reducing nuclear localization of the forkhead box-O1 (FoxO1) transcription factor via activation of the phosphoinositide-3-kinase (PI3K)/Akt pathway. Using SZ95 sebocytes as a model, we investigated the effect of the most important insulinotropic western dietary factors, IGF-1 and insulin on acne. SZ95 sebocytes were stimulated with different concentrations of IGF-1 and insulin (0.001, 0.01, 0.1 and 1 μM) for 15 to 120 min ± PI3K inhibitor LY294002 (50 μM). Cytoplasmic and nuclear protein expression of p-Akt and p-FoxO1 as well as FoxO transcriptional activity was analysed. In addition, the proliferation and differentiation of sebocytes and their TLR2/4 expression were determined. We found that high concentrations of IGF-1 and insulin differentially stimulate the PI3K/Akt/FoxO1 pathway by an early up-regulation of cytoplasmic p-Akt and delayed up-regulation of p-FoxO1 resulting in FoxO1 shift to the cytoplasm and the reduction of FoxO transcriptional activity, physiological serum concentration had no effect. IGF-1 at concentrations of 0.1 and 1 μM significantly reduced proliferation but increased differentiation of sebocytes to a greater extent than insulin (0.1 and 1 μM), but up-regulated TLR2/4 expression to comparable extent. These data provide the first in vitro evidence that FoxO1 principally might be involved in the regulation of growth-factor-stimulatory effects on sebaceous lipogenesis and inflammation in the pathological condition of acne. However, the in vivo significance under physiological conditions remains to be elucidated. Highlights: We investigated the role of FoxO1 as a putative regulator in the acne pathogenesis. IGF-1 and insulin activate PI3K and up-regulate p-Akt and p-FoxO1 in SZ95 sebocytes. IGF-1 and insulin reduce nuclear FoxO1 and its transcriptional activity. SZ95 differentiation increases and proliferation decreases via PI3K activation. IGF-1 and insulin increase expression of pro-inflammatory TLR2/4.