Mitochondrial Impairment Mechanism in D-galactose-induced Senescence in Experimental Fibroblast Cell Model

Abstract

Abstract.To establish an effective model for cellular senescence, human embryo lung fibroblast cells (MRC-5) were cultured in D-galactose (D-Gal) medium respectively, as control, same concentration of D-glucose (D-Glu) was used. Decrease in cell proliferation, increase in senescence associated β-galactosidase activity, up-expression of p21 protein, and cell cycle arrest at S-phage were observed in D-Gal-treated cells. Meanwhile, D-Gal-treated cells showed the significant increased ROS and MDA level and decreased SOD activity. Furthermore, mitochondrial impairment and decrease in efficiency of oxidative phosphorylation (OXPHOS) was induced by D-Gal as evidenced by the decreased transmembrane potential, reduction of ATP production and changes of respiration function. Additionally, the significant decrease of mitochondrial quantity, mitochondrial DNA (mtDNA) copy number and increased mtDNA damage were detected in D-Gal-treated cells. Our data demonstrate that D-Gal induces mitochondrial oxidative impairment associated with increased generation of ROS, ultimately inhibiting the ATP synthesis which contributes to premature cellular senescence.

Galactose-Induced Skin Aging: The Role of Oxidative Stress

“…It was established that D-gal can disturb ubiquitin-proteasome system [125] and thus enhance the levels of glycated proteins in the cells. It should also be noted that autophagic flux alterations were detected recently in D-gal-treated skin fibroblasts [111,117]. This can provide an insight on the additional mechanism of the acceleration of D-gal-induced cell senescence.…”

“…It can be assumed that D-gal induces skin aging in two ways: the direct impact of D-gal on skin cells and/or the indirect effect associated with the accumulation of toxic metabolites in the skin. Our understanding at this age leads us to suggest that cytotoxicity of D-gal is based on activated oxidative stress, as confirmed by the in vitro [65,[111][112][113][114][115][116][117][118]144] and in vivo experiments [70, 72-74, 76, 78, 82-85].…”

“…The role of both nuclear and mtDNA damage in skin cells induced by excessive ROS is well described in relation to the UV-induced skin aging process [9,126]. Similar DNA damage was found in fibroblasts treated with D-gal [111,117,118]. It was established that oxidative DNA damage activates the downstream mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated kinase (ERK), p38, and c-Jun NH2-terminal kinase (JNK) [127].…”

“…It was also shown that at a pathologically high concentration (greater than 5.0 mM), D-gal increases lipid peroxidation, decreases total sulfhydryl content, and alters antioxidant defenses in rat plasma and erythrocytes [45]. Moreover, increased expression of biomarkers of the oxidative stress and decreased antioxidant defense were induced by D-gal in human fibroblasts in vitro [111,112].…”

“…It was reported that D-gal reduced the efficiency of oxidative phosphorylation (OXPHOS) via declined transmembrane potential, decreasing ATP production and changing of respiratory function [65,113,114]. Upon galactose exposure, human fibroblasts tended to reduce the mitochondrial quantity and mitochondrial DNA (mtDNA) copy number and enhance mtDNA damage [111,117,118].…”