Modulators of mitochondrial ATP-sensitive potassium channel affect cytotoxicity of heavy metals: Action on isolated rat liver mitochondria and AS-30D ascites hepatoma cells

Mitochondrial administration alleviates lead- and cadmium-induced toxicity in rat renal cells

The role of heavy metals such as lead (Pb) and cadmium (Cd) in the etiology of many diseases has been proven. Also, these heavy metals can affect the normal mitochondrial function. Mitochondrial administration therapy is one of the methods used by researchers to help improve mitochondrial defects and diseases. The use of isolated mitochondria as a therapeutic approach has been investigated in in vivo and in vitro studies. Accordingly, in this study, the effects of mitochondrial administration on the improvement of toxicity caused by Pb and Cd in renal proximal tubular cells (RPTC) have been investigated. The results showed that treatment to Pb and Cd caused an increase in the level of free radicals, lipid peroxidation (LPO) content, mitochondrial and lysosomal membrane damage, and also a decrease in the reduced glutathione content in RPTC. In addition, reports have shown an increase in oxidized glutathione content and changes in energy (ATP) levels. Following, the results have shown the protective role of mitochondrial administration in improving the toxicity caused by Pb and Cd in RPTC. Furthermore, the mitochondrial internalization into RPT cells is mediated through actin-dependent endocytosis. So, it could be suggested that the treatment of Pb- and Cd-induced cytotoxicity in RPTC could be carried out through mitochondria administration.

Mitochondrial dysfunction mediated by thioredoxin-interacting protein: A crucial determinant in di(2-ethylhexyl) phthalate-induced liver failure

Di(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer that can interfere with the endocrine system and cause liver damage. However, the molecular mechanism of DEHP-induced liver injury is unclear. This study aimed to investigate the effects of DEHP on liver function and its relationship with thioredoxin-interacting protein (TXNIP) and mitochondrial oxidative stress pathway. We used C57BL/6 J mice and THLE-2 liver cells as in vivo and in vitro models, respectively, and treated them with different doses of DEHP, and measured the relevant biochemical indicators and molecular markers. We found that DEHP significantly increased the expression of TXNIP and NLRP3, while decreasing the expression of mitochondrial functional proteins, such as PGC-1α, TFAM, NRF1, NDUHA9, SDHA, MFN1. This resulted in mitochondrial dysfunction, manifested by reduced ATP generation, increased inflammatory factor release, elevated liver enzyme indicators, decreased mitochondrial membrane potential and increased oxidative stress. We further demonstrated that TXNIP upregulation activated NF-κB and MAPK signaling pathways, such as NF-κB, IκB, TAB2, TRAF6, ERK1, JNK, p38 MAPK, MEK1, which exacerbated oxidative stress and inflammation, leading to liver damage. Additionally, we found that treatment with the antioxidant MitoQ partially alleviated DEHP-induced liver toxicity, while silencing TXNIP more effectively restored mitochondrial function. Our study supports the hypothesis that DEHP induces mitochondrial oxidative stress through the TXNIP signaling pathway, resulting in liver dysfunction in mice, and suggests possible links between endocrine-disrupting chemicals and human diseases.

Mitochondrial Oxidative Stress Is the General Reason for Apoptosis Induced by Different-Valence Heavy Metals in Cells and Mitochondria

This review analyzes the causes and consequences of apoptosis resulting from oxidative stress that occurs in mitochondria and cells exposed to the toxic effects of different-valence heavy metals (Ag+, Tl+, Hg2+, Cd2+, Pb2+, Al3+, Ga3+, In3+, As3+, Sb3+, Cr6+, and U6+). The problems of the relationship between the integration of these toxic metals into molecular mechanisms with the subsequent development of pathophysiological processes and the appearance of diseases caused by the accumulation of these metals in the body are also addressed in this review. Such apoptosis is characterized by a reduction in cell viability, the activation of caspase-3 and caspase-9, the expression of pro-apoptotic genes (Bax and Bcl-2), and the activation of protein kinases (ERK, JNK, p53, and p38) by mitogens. Moreover, the oxidative stress manifests as the mitochondrial permeability transition pore (MPTP) opening, mitochondrial swelling, an increase in the production of reactive oxygen species (ROS) and H2O2, lipid peroxidation, cytochrome c release, a decline in the inner mitochondrial membrane potential (ΔΨmito), a decrease in ATP synthesis, and reduced glutathione and oxygen consumption as well as cytoplasm and matrix calcium overload due to Ca2+ release from the endoplasmic reticulum (ER). The apoptosis and respiratory dysfunction induced by these metals are discussed regarding their interaction with cellular and mitochondrial thiol groups and Fe2+ metabolism disturbance. Similarities and differences in the toxic effects of Tl+ from those of other heavy metals under review are discussed. Similarities may be due to the increase in the cytoplasmic calcium concentration induced by Tl+ and these metals. One difference discussed is the failure to decrease Tl+ toxicity through metallothionein-dependent mechanisms. Another difference could be the decrease in reduced glutathione in the matrix due to the reversible oxidation of Tl+ to Tl3+ near the centers of ROS generation in the respiratory chain. The latter may explain why thallium toxicity to humans turned out to be higher than the toxicity of mercury, lead, cadmium, copper, and zinc.