Hydrogen sulfide attenuates homocysteine‐induced osteoblast dysfunction by inhibiting mitochondrial toxicity

Abstract

Homocysteine (Hcy) is detrimental to bone health in a mouse model of diet-induced hyperhomocysteinemia (HHcy). However, little is known about Hcy-mediated osteoblast dysfunction via mitochondrial oxidative damage. Hydrogen sulfide (H2S) has potent antioxidant, anti-inflammatory, and antiapoptotic effects. In this study, we hypothesized that the H2S mediated recovery of osteoblast dysfunction by maintaining mitochondrial biogenesis in Hcy-treated osteoblast cultures in vitro. MC3T3-E1 osteoblastic cells were exposed to Hcy treatment in the presence or absence of an H2S donor (NaHS). Cell viability, osteogenic differentiation, reactive oxygen species (ROS) production were determined. Mitochondrial DNA copy number, adenosine triphosphate (ATP) production, and oxygen consumption were also measured. Our results demonstrated that administration of Hcy increases the intracellular Hcy level and decreases intracellular H2S level and expression of the cystathionine β-synthase/Cystathionine γ-lyase system, thereby inhibiting osteogenic differentiation. Pretreatment with NaHS attenuated Hcy-induced mitochondrial toxicity (production of total ROS and mito-ROS, ratio of mitochondrial fission (DRP-1)/fusion (Mfn-2)) and restored ATP production and mitochondrial DNA copy numbers as well as oxygen consumption in the osteoblast as compared with the control, indicating its protective effects against Hcy-induced mitochondrial toxicity. In addition, NaHS also decreased the release of cytochrome c from the mitochondria to the cytosol, which induces cell apoptosis. Finally, flow cytometry confirmed that NaHS can rescue cells from apoptosis induced by Hcy. Our studies strongly suggest that NaHS has beneficial effects on mitochondrial toxicity, and could be developed as a potential therapeutic agent against HHcy-induced mitochondrial dysfunction in cultured osteoblasts in vitro.

Permanent cystathionine-β-Synthase gene knockdown promotes inflammation and oxidative stress in immortalized human adipose-derived mesenchymal stem cells, enhancing their adipogenic capacity

“…In agreement with current data, the administration of diallyl disulfide, a slow H 2 S donor [ 43 ], restored hAMSC stemness via inhibition of intracellular ROS levels [ 44 ]. The relevance of CBS on osteogenesis has been previously reported [ [45] , [46] , [47] ]. Interestingly, one of these studies demonstrated that exogenous homocysteine administration increased intracellular homocysteine levels, and resulted in increased ROS, altered mitochondrial function, reduced expression of CBS gene and intracellular H 2 S level, and in consequence, inhibiting its capacity to differentiate into osteogenic linage [ 47 ].…”

Gastrodin prevents homocysteine‐induced human umbilical vein endothelial cells injury via PI3K/Akt/eNOS and Nrf2/ARE pathway

“…Hcy decreases NO production through the regulation of Cav‐1 expression and the interaction of Cav‐1 and eNOS 7 . In addition, Hcy can induce reactive oxygen species (ROS) production, subsequently leading to apoptosis 8 . Moreover, the Hcy‐induced reduction of the Nrf2‐dependent antioxidant defence system suppressed antioxidant enzymes downstream of Nrf2 9,10 .…”

“…7 In addition, Hcy can induce reactive oxygen species (ROS) production, subsequently leading to apoptosis. 8 Moreover, the Hcy-induced reduction of the Nrf2-dependent antioxidant defence system suppressed antioxidant enzymes downstream of Nrf2. 9,10 Hence, research has indicated that decreasing the accumulation of ROS and restoring NO production could inhibit Hcy-induced injury.…”

Hydrogen Sulfide in Bone Tissue Regeneration and Repair: State of the Art and New Perspectives

“…In particular, CSE is the predominant source of H 2 S in OBs [81]. H 2 S plays a cytoprotective role in bone cells; it protects OBs against homocysteine-induced mitochondrial toxicity [83]; and OBs against hydrogen peroxide (H 2 O 2 )-induced cell death and apoptosis [84].…”