Digestive Diseases and Sciences

, Volume 57, Issue 6, pp 1525–1536

PER1 Modulates SGLT1 Transcription In Vitro Independent of E-box Status

Authors

    • Department of SurgeryBrigham and Women’s Hospital
    • Department of SurgeryHarvard Medical School
    • Division of Gastroenterology, School of Clinical SciencesUniversity of Liverpool
    • Thorn 1503Brigham and Women’s Hospital
  • Adam T. Stearns
    • Department of SurgeryBrigham and Women’s Hospital
    • Department of SurgeryHarvard Medical School
    • Department of Physiology, Anatomy and GeneticsUniversity of Oxford
  • Stanley W. Ashley
    • Department of SurgeryBrigham and Women’s Hospital
    • Department of SurgeryHarvard Medical School
  • David B. Rhoads
    • Department of SurgeryHarvard Medical School
    • Pediatric Endocrine UnitMass General Hospital for Children
    • Department of SurgeryBrigham and Women’s Hospital
    • Department of SurgeryHarvard Medical School
Original Article

DOI: 10.1007/s10620-012-2166-8

Cite this article as:
Balakrishnan, A., Stearns, A.T., Ashley, S.W. et al. Dig Dis Sci (2012) 57: 1525. doi:10.1007/s10620-012-2166-8

Abstract

Background and Aims

The intestine demonstrates profound circadian rhythmicity in glucose absorption in rodents, mediated entirely by rhythmicity in the transcription, translation, and function of the sodium glucose co-transporter SGLT1 (Slc5a1). Clock genes are rhythmic in the intestine and have been implicated in the regulation of rhythmicity of other intestinal genes; however, their role in the regulation of SGLT1 is unknown. We investigated the effects of one clock gene, PER1, on SGLT1 transcription in vitro.

Methods

Caco-2 cells were stably transfected with knockdown vectors for PER1 and mRNA expression of clock genes and SGLT1 determined using quantitative polymerase chain reaction (qPCR). Chinese hamster ovary (CHO) cells were transiently cotransfected with combinations of the PER1 expression vectors and the wild-type SGLT1-luciferase promoter construct or the promoter with mutated E-box sequences.

Results

Knockdown of PER1 increased native SGLT1 expression in Caco-2 enterocytes, while promoter studies confirmed that the inhibitory activity of PER1 on SGLT1 occurs via the proximal 1 kb of the SGLT1 promoter. E-box sites exerted a suppressive effect on the SGLT1 promoter; however, mutation of E-boxes had little effect on the inhibitory activity of PER1 on the SGLT1 promoter suggesting that the actions of PER1 on SGLT1 are independent of E-boxes.

Conclusions

Our findings suggest that PER1 exerts an indirect suppressive effect on SGLT1, possibly acting via other clock-controlled genes binding to non-E-box sites on the SGLT1 promoter. Understanding the regulation of rhythmicity of SGLT1 may lead to new treatments for the modulation of SGLT1 expression in conditions such as malabsorption, diabetes, and obesity.

Keywords

Clock genesSGLT1CircadianPER1Intestine

Abbreviations

Bmal1

Brain muscle Arnt-like 1

Cry

Cryptochrome

Mdr1

Multidrug resistance 1

mRNA

Messenger ribonucleic acid

Nhe3

Na+/H+ exchanger

Per

Period

PVDF

Polyvinylidenefluoride

SGLT1

Sodium glucose cotransporter 1

Supplementary material

10620_2012_2166_MOESM1_ESM.doc (48 kb)
Supplementary material 1 (DOC 48 kb)

Copyright information

© Springer Science+Business Media, LLC 2012