Issue 9, 2017

Quantitative distribution of Zn, Fe and Cu in the human lens and study of the Zn–metallothionein redox system in cultured lens epithelial cells by elemental MS

Abstract

The human lens is constantly subjected to exogenous and endogenous stressors, leading to oxidative cellular damage and, with time, to cataract formation. Metallothioneins (MTs) are a group of important enzymes that use metals (i.e., Zn and Cu) to protect tissues from the deleterious effects of free radicals associated with oxidative stress. This work combines elemental mass spectrometry with bio-analytical methodologies to determine (i) the total amount, the quantitative speciation and the cellular distribution of trace elements (i.e., Zn, Fe, and Cu) in human lenses and their corresponding capsules; and (ii) the effects of “exogenous” metal (i.e., 68ZnSO4, isotopically enriched in 68Zn) and stressor (i.e., IL-1α) on the zinc–MT redox system in cultured human lens epithelial cells (HLEsv) in vitro. Of all the elements analyzed, Zn was the most abundant, and it was equally present in both the capsule (9.7 ± 2.5 μg g−1 tissue) and the lens (9.5 ± 1.2 μg g−1 tissue). In contrast, Fe was found to be more than 6-fold more abundant in the capsule (1.6 ± 0.4 μg g−1) than in the lens (0.2 ± 0.1 μg g−1). Zinc in the lens is mainly associated with high molecular mass proteins, whereas in the capsule it is mostly bound to low and medium molecular mass proteins. The localization of Zn, Cu and MTs in the lens showed their preferential co-distribution in the lens epithelial cell layer, underneath the anterior capsule. Exogenous Zn is capable of inducing a stoichiometric change in MT proteins from Zn3–MT to Zn7–MT within lens epithelial cells in vitro, which may be related to their antioxidant capacity.

Graphical abstract: Quantitative distribution of Zn, Fe and Cu in the human lens and study of the Zn–metallothionein redox system in cultured lens epithelial cells by elemental MS

Supplementary files

Article information

Article type
Paper
Submitted
30 Nov. 2016
Accepted
07 Jūn. 2017
First published
07 Jūn. 2017

J. Anal. At. Spectrom., 2017,32, 1746-1756

Quantitative distribution of Zn, Fe and Cu in the human lens and study of the Zn–metallothionein redox system in cultured lens epithelial cells by elemental MS

H. González-Iglesias, C. Petrash, S. Rodríguez-Menéndez, M. García, L. Álvarez, L. Fernández-Vega Cueto, B. Fernández, R. Pereiro, A. Sanz-Medel and M. Coca-Prados, J. Anal. At. Spectrom., 2017, 32, 1746 DOI: 10.1039/C6JA00431H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements