Insulin Regulates Hypoxia-Inducible Factor-1α Transcription by Reactive Oxygen Species Sensitive Activation of Sp1 in 3T3-L1 Preadipocyte

Sudipta Biswas, Reshmi Mukherjee, Nisha Tapryal, Amit K. Singh, Chinmay K. Mukhopadhyay

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Oxygen sensing transcription factor HIF-1 is activated due to accumulation of regulatory subunit HIF-1α by posttranslational stability mechanism during hypoxia or by several other stimuli even in normoxia. HIF-1α is also regulated by NF-kB mediated transcription mechanism. Reactive oxygen species (ROS) act as an important regulator of HIF-1 either by affecting prolyl hydroxylase activity, the critical determinant of HIF-1α stabilization or by activating NF-kB to promote HIF-1α transcription. Insulin is known to activate HIF-1 by a ROS dependent mechanism but the molecular mechanism of HIF-1α regulation is not known so far. Here we show that insulin regulates HIF-1α by a novel transcriptional mechanism by a ROS-sensitive activation of Sp1 in 3T3-L1 preadipocyte. Insulin shows little effect on HIF-1α protein stability, but increases HIF-1α promoter activity. Mutation analyses, electrophoretic mobility shift assay and chromatin immunoprecipitation assay confirm the role of Sp1 in HIF-1α transcription. We further demonstrate that insulin-induced ROS generation initiates signaling pathway involving phosphatidylinositol 3-kinase and protein kinase C for Sp1 mediated HIF-1α transcription. In summary, we reveal that insulin regulates HIF-1α by a novel transcriptional mechanism involving Sp1.

Original languageEnglish (US)
Article numbere62128
JournalPLoS One
Volume8
Issue number4
DOIs
StatePublished - Apr 23 2013
Externally publishedYes

Fingerprint

Hypoxia-Inducible Factor 1
Transcription
reactive oxygen species
Reactive Oxygen Species
insulin
transcription (genetics)
Chemical activation
Insulin
transcription factor NF-kappa B
NF-kappa B
Assays
procollagen-proline dioxygenase
Phosphatidylinositol 3-Kinase
Prolyl Hydroxylases
Electrophoretic mobility
normoxia
Protein Stability
Chromatin Immunoprecipitation
phosphatidylinositol 3-kinase
protein kinase C

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Insulin Regulates Hypoxia-Inducible Factor-1α Transcription by Reactive Oxygen Species Sensitive Activation of Sp1 in 3T3-L1 Preadipocyte. / Biswas, Sudipta; Mukherjee, Reshmi; Tapryal, Nisha; Singh, Amit K.; Mukhopadhyay, Chinmay K.

In: PLoS One, Vol. 8, No. 4, e62128, 23.04.2013.

Research output: Contribution to journalArticle

Biswas, Sudipta ; Mukherjee, Reshmi ; Tapryal, Nisha ; Singh, Amit K. ; Mukhopadhyay, Chinmay K. / Insulin Regulates Hypoxia-Inducible Factor-1α Transcription by Reactive Oxygen Species Sensitive Activation of Sp1 in 3T3-L1 Preadipocyte. In: PLoS One. 2013 ; Vol. 8, No. 4.
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