Selenoproteome Expression Studied by Non-Radioactive Isotopic Selenium-Labeling in Human Cell Lines.

Jordan Sonet,Katarzyna Bierla,Anne-Laure Bulteau,Ryszard Lobinski,Maurine Mosca,Laurent Chavatte,Sandra Mounicou,Zahia Touat-Hamici

doi:10.3390/ijms22147308

Abstract

Selenoproteins, in which the selenium atom is present in the rare amino acid selenocysteine, are vital components of cell homeostasis, antioxidant defense, and cell signaling in mammals. The expression of the selenoproteome, composed of 25 selenoprotein genes, is strongly controlled by the selenium status of the body, which is a corollary of selenium availability in the food diet. Here, we present an alternative strategy for the use of the radioactive 75Se isotope in order to characterize the selenoproteome regulation based on (i) the selective labeling of the cellular selenocompounds with non-radioactive selenium isotopes (76Se, 77Se) and (ii) the detection of the isotopic enrichment of the selenoproteins using size-exclusion chromatography followed by inductively coupled plasma mass spectrometry detection. The reliability of our strategy is further confirmed by western blots with distinct selenoprotein-specific antibodies. Using our strategy, we characterized the hierarchy of the selenoproteome regulation in dose–response and kinetic experiments.

Highlights

The vital role of the essential trace element selenium (Se) in human health has been widely reported
size exclusion chromatography (SEC) was linked to an UV280nm monitor followed by an inductively coupled plasma-mass spectrometry (ICP MS) tuned for a multi-isotopic selenium detection
When cells were grown in a medium containing 100 nM of selenium, we found that selenoproteins were the major forms of selenocompounds found in cellular extracts

Summary

Introduction

The vital role of the essential trace element selenium (Se) in human health has been widely reported. Despite the essential nature of selenium, the range of its optimal intake is quite narrow and its toxicity can be quite achieved depending on its chemical speciation. Twenty-five selenoprotein genes have been identified in the human genome and give rise to selenoproteome expression in tissue and cell-line specific patterns [12]. The selenoproteome is primarily regulated by the bioavailability of selenium from food or from a cell culture medium. This selenium-dependent regulation follows a specific hierarchy that stipulates that “house-keeping” members are kept constant at the expense of “stress-regulated” members, which respond to changes in the selenium level [6,8,13]. Other stimuli, including H2O2-induced oxidative stress and replicative senescence, are able to modulate selenoprotein expression but follow distinct hierarchies [4,14,15,16,17,18]

Objectives

Methods

Results

Discussion

Conclusion