Research output: Contribution to journal › Article › peer-review
Insulin downregulates C3 gene expression in human HepG2 cells through activation of PPARγ. / Shavva, Vladimir S.; Bogomolova, Alexandra M.; Efremov, Alexander M.; Trofimov, Alexander N.; Nikitin, Artemy A.; Babina, Anna V.; Nekrasova, Ekaterina V.; Dizhe, Ella B.; Oleinikova, Galina N.; Missyul, Boris V.; Orlov, Sergey V.
In: European Journal of Cell Biology, Vol. 97, No. 3, 01.04.2018, p. 204-215.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Insulin downregulates C3 gene expression in human HepG2 cells through activation of PPARγ
AU - Shavva, Vladimir S.
AU - Bogomolova, Alexandra M.
AU - Efremov, Alexander M.
AU - Trofimov, Alexander N.
AU - Nikitin, Artemy A.
AU - Babina, Anna V.
AU - Nekrasova, Ekaterina V.
AU - Dizhe, Ella B.
AU - Oleinikova, Galina N.
AU - Missyul, Boris V.
AU - Orlov, Sergey V.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - C3 is an acute phase protein, and thus its plasma concentration increases quickly and drastically during the onset of inflammation. Insulin plays a complex role in inflammation. Elevated level of plasma C3 was shown to correlate with heightened fasting insulin levels and insulin resistance and appears to be a risk factor for the cardiovascular disease and atherosclerosis. The main source of plasma C3 is liver. Nothing is known about effects of insulin on C3 gene expression and protein secretion by hepatocytes. In light of these data we asked if insulin is capable of regulating C3 production in hepatocytes. Here we show that insulin downregulates C3 gene expression in human hepatoma cells HepG2 through activation of PI3K, mTORC1, p38 and MEK1/2 signaling pathways. Transcription factors PPARα, PPARγ, HNF4α and NF-κB are important contributors to this process. Insulin activates PPARγ through PI3K/Akt/mTORC1 pathway, which results in PPARγ binding to DR4 and DR0 cis-acting elements within the C3 promoter and subsequent displacement of HNF4α and PPARα from these sites. As a result PPARα/NF-κB complex, which exists on C3 promoter, is broken down and C3 gene expression is downregulated. The data obtained can potentially be used to explain the molecular mechanism underlying the correlation between heightened level of plasma C3 and insulin resistance in humans.
AB - C3 is an acute phase protein, and thus its plasma concentration increases quickly and drastically during the onset of inflammation. Insulin plays a complex role in inflammation. Elevated level of plasma C3 was shown to correlate with heightened fasting insulin levels and insulin resistance and appears to be a risk factor for the cardiovascular disease and atherosclerosis. The main source of plasma C3 is liver. Nothing is known about effects of insulin on C3 gene expression and protein secretion by hepatocytes. In light of these data we asked if insulin is capable of regulating C3 production in hepatocytes. Here we show that insulin downregulates C3 gene expression in human hepatoma cells HepG2 through activation of PI3K, mTORC1, p38 and MEK1/2 signaling pathways. Transcription factors PPARα, PPARγ, HNF4α and NF-κB are important contributors to this process. Insulin activates PPARγ through PI3K/Akt/mTORC1 pathway, which results in PPARγ binding to DR4 and DR0 cis-acting elements within the C3 promoter and subsequent displacement of HNF4α and PPARα from these sites. As a result PPARα/NF-κB complex, which exists on C3 promoter, is broken down and C3 gene expression is downregulated. The data obtained can potentially be used to explain the molecular mechanism underlying the correlation between heightened level of plasma C3 and insulin resistance in humans.
KW - C3
KW - HepG2
KW - HNF4α
KW - Insulin
KW - PPARα
KW - PPARγ
UR - http://www.scopus.com/inward/record.url?scp=85043508015&partnerID=8YFLogxK
U2 - 10.1016/j.ejcb.2018.03.001
DO - 10.1016/j.ejcb.2018.03.001
M3 - Article
C2 - 29550264
AN - SCOPUS:85043508015
VL - 97
SP - 204
EP - 215
JO - European Journal of Cell Biology
JF - European Journal of Cell Biology
SN - 0171-9335
IS - 3
ER -
ID: 38625222