Oxidative Medicine and Cellular Longevity

Oxidative Medicine and Cellular Longevity / 2015 / Article
Special Issue

Hydrogen Sulfide Signaling in Oxidative Stress and Aging Development

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Research Article | Open Access

Volume 2015 |Article ID 804603 | https://doi.org/10.1155/2015/804603

Liping Zhang, Yanxi Pei, Hongjiao Wang, Zhuping Jin, Zhiqiang Liu, Zengjie Qiao, Huihui Fang, Yanjie Zhang, "Hydrogen Sulfide Alleviates Cadmium-Induced Cell Death through Restraining ROS Accumulation in Roots of Brassica rapa L. ssp. pekinensis", Oxidative Medicine and Cellular Longevity, vol. 2015, Article ID 804603, 11 pages, 2015. https://doi.org/10.1155/2015/804603

Hydrogen Sulfide Alleviates Cadmium-Induced Cell Death through Restraining ROS Accumulation in Roots of Brassica rapa L. ssp. pekinensis

Academic Editor: Honglian Shi
Received29 Oct 2014
Accepted15 Dec 2014
Published11 May 2015

Abstract

Hydrogen sulfide (H2S) is a cell signal molecule produced endogenously and involved in regulation of tolerance to biotic and abiotic stress in plants. In this work, we used molecular biology, physiology, and histochemical methods to investigate the effects of H2S on cadmium- (Cd-) induced cell death in Chinese cabbage roots. Cd stress stimulated a rapid increase of endogenous H2S in roots. Additionally, root length was closely related to the cell death rate. Pretreatment with sodium hydrosulfide (NaHS), a H2S donor, alleviated the growth inhibition caused by Cd in roots—this effect was more pronounced at 5 μM NaHS. Cd-induced cell death in roots was significantly reduced by 5 μM NaHS treatment. Under Cd stress, activities of the antioxidant enzymes were significantly enhanced in roots. NaHS + Cd treatment made their activities increase further compared with Cd exposure alone. Enhanced antioxidant enzyme activity led to a decline in reactive oxygen species accumulation and lipid peroxidation. In contrast, these effects were reversed by hydroxylamine, a H2S inhibitor. These results suggested that H2S alleviated the cell death caused by Cd via upregulation of antioxidant enzyme activities to remove excessive reactive oxygen species and reduce cell oxidative damage.

1. Introduction

Recently, hydrogen sulfide (H2S) has become appreciated as an endogenous signaling molecule, after nitric oxide and carbon monoxide [1]. In the 1980s, H2S release in plants was discovered [2]. Some genes encoding these enzymes, which are responsible for endogenous H2S generation, were recently cloned in higher plants. Two cysteine desulfhydrases with the ability to decompose cysteine to pyruvate, ammonia, and H2S have been identified: L-cysteine desulfhydrase (LCD) with L-cysteine as substrate and D-cysteine desulfhydrase (DCD) with D-cysteine as substrate [3, 4]. Since then, Álvarez et al. reported a novel L-cysteine desulfhydrase, named DES1, which is an O-acetylserine(thiol)lyase homolog [5]. Some enzymes with similar function are being discovered, but detailed information remains limited.

As a signal molecule, H2S plays a vital role in regulating the growth and development of plants; moreover the important effects of H2S in plants response to some stresses have been intensely discussed in recent years. Increasing amounts of evidence illustrate the physiological functions of H2S in the growth and development of plants, such as enhancing photosynthesis, regulating seed germination, stomatal movement, root formation, and flower senescence [610]. In addition, H2S, as a pivotal role in plant response to environmental stimuli, such as improving drought resistance, coping with heat stress, enhancing freezing tolerance, and involvement in plants response to heavy metal, osmotic, and salt stresses, has also been reported [1115]. The protective roles of H2S alleviating stresses have focused on promoting antioxidant capacity to decrease reactive oxygen species (ROS) accumulation or interacting with other signaling molecules. However, it is just the beginning of studying H2S-mediated stress responses, and the potential molecular mechanisms remain ambiguous.

Cadmium (Cd) is a major environmental pollutant and can be easily transported from the roots to other parts of plant. Cd also displays deleterious effects on seed germination, growing development, and photosynthesis [16, 17]. Treatment with high Cd concentrations can trigger programmed cell death (P