Adipose-derived mesenchymal stem cells rescue rat hippocampal cells from aluminum oxide nanoparticle-induced apoptosis via regulation of P53, Aβ, SOX2, OCT4, and CYP2E1

Prevention of methylmercury-triggered ROS-mediated impairment of embryo development by co-culture with adult adipose-derived mesenchymal stem cells

Methylmercury (MeHg) is a potent toxin that exerts deleterious effects on human health via environmental contamination. Significant effects of MeHg on neuronal development in embryogenesis have been reported. Recently, our group demonstrated that MeHg exerts toxic effects on pre- and post-implantation embryonic development processes from zygote to blastocyst stage. Our results showed that MeHg impairs embryo development by induction of apoptosis through reactive oxygen species (ROS) generation that triggers caspase-3 cleavage and activation, which, in turn, stimulates p21-activated kinase 2 (PAK2) activity. Importantly, ROS were identified as a key upstream regulator of apoptotic events in MeHg-treated blastocysts. Data from the current study further confirmed that MeHg exerts hazardous effects on cell proliferation, apoptosis, implantation, and pre- and post-implantation embryo development. Notably, MeHg-induced injury was markedly prevented by co-culture with adipose-derived mesenchymal stem cells (ADMSCs) in vitro. Furthermore, ADMSC injection significantly reduced MeHg-mediated deleterious effects on embryo, placenta, and fetal development in vivo. Further investigation of the regulatory mechanisms by which co-cultured ADMSCs could prevent MeHg-induced impairment of embryo development revealed that ADMSCs effectively reduced ROS generation and its subsequent downstream apoptotic events, including loss of mitochondrial membrane potential and activation of caspase-3 and PAK2. The collective findings indicate that co-culture with mesenchymal stem cells (MSCs) or utilization of MSC-derived cell-conditioned medium offers an effective potential therapeutic strategy to prevent impairment of embryo development by MeHg.

Gallic acid rescues uranyl acetate induced-hepatic dysfunction in rats by its antioxidant and cytoprotective potentials

BACKGROUND

The liver was identified as a primary target organ for the chemo-radiological effects of uranyl acetate (UA). Although the anti-oxidant and anti-apoptotic properties of gallic acid (GA) make it a promising phytochemical to resist its hazards, there is no available data in this area of research.

METHODS

To address this issue, eighteen rats were randomly and equally divided into three groups. One group was received carboxymethyl cellulose (vehicle of GA) and kept as a control. The UA group was injected intraperitoneally with UA at a single dose of 5 mg/kg body weight. The third group (GA + UA group) was treated with GA orally at a dose of 100 mg/kg body weight for 14 days before UA exposure. UA was injected on the 15th day of the experiment in either the UA group or the GA + UA group. The biochemical, histological, and immunohistochemical findings in the GA + UA group were compared to both control and UA groups.

RESULTS

The results showed that UA exposure led to a range of adverse effects. These included elevated plasma levels of aspartate aminotransferase, lactate dehydrogenase, total protein, globulin, glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and very-low-density lipoprotein and decreased plasma levels of high-density lipoprotein cholesterol. The exposure also disrupted the redox balance, evident through decreased plasma total antioxidant capacity and hepatic nitric oxide, superoxide dismutase, reduced glutathione, glutathione-S-transferase, glutathione reductase, and glutathione peroxidase and increased hepatic oxidized glutathione and malondialdehyde. Plasma levels of albumin and alanine aminotransferase did not significantly change in all groups. Histopathological analysis revealed damage to liver tissue, characterized by deteriorations in tissue structure, excessive collagen accumulation, and depletion of glycogen. Furthermore, UA exposure up-regulated the immuno-expression of cleaved caspase-3 and down-regulated the immuno-expression of nuclear factor-erythroid-2-related factor 2 in hepatic tissues, indicating an induction of apoptosis and oxidative stress response. However, the pre-treatment with GA proved to be effective in mitigating these negative effects induced by UA exposure, except for the disturbances in the lipid profile.

CONCLUSIONS

The study suggests that GA has the potential to act as a protective agent against the adverse effects of UA exposure on the liver. Its ability to restore redox balance and inhibit apoptosis makes it a promising candidate for countering the harmful effects of chemo-radiological agents such as UA.

Al2O3 nanoparticles trigger the embryonic hepatotoxic response and potentiate TNF-α-induced apoptosis-modulatory effect of p38 MAPK and JNK inhibitors

Recent evidences illustrated that the release of aluminum oxide nanoparticles (Al₂O₃-NPs) into the biosphere may pose risk to the environment and cause adverse effects on living organisms including humans. The current study assessed the hepatotoxic effects of Al₂O₃-NPs on developing chicken embryo and cell culture models. Results demonstrated that Al₂O₃-NPs exposure causes histological abnormalities and increased the level of tissue damage markers (ALP, AST, and ALT) in the embryonic liver. Furthermore, increased oxidative stress (TBARS) and impaired function of antioxidant enzymes (SOD, CAT, and GPx) were also observed. Moreover, it adversely affects red blood cells (RBC) morphology, liver metabolism, and stress response gene expression (HO-1 and NQO-1). Dose-dependent ROS generation and cytotoxic response in addition to potentiating effect on tumor necrosis factor alpha (TNF-α)-induced apoptosis (caspase-3 activity) were also observed. Inhibition of p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK) pathways modulates Al₂O₃-NPs-induced apoptosis in HepG2 cells. Novel mechanisms behind embryonic hepatotoxicity, cytotoxic potentiating effects, and possible prevention strategies have been explored.

Impact of Graphene Derivatives as Artificial Extracellular Matrices on Mesenchymal Stem Cells

Thanks to stem cells' capability to differentiate into multiple cell types, damaged human tissues and organs can be rapidly well-repaired. Therefore, their applicability in the emerging field of regenerative medicine can be further expanded, serving as a promising multifunctional tool for tissue engineering, treatments for various diseases, and other biomedical applications as well. However, the differentiation and survival of the stem cells into specific lineages is crucial to be exclusively controlled. In this frame, growth factors and chemical agents are utilized to stimulate and adjust proliferation and differentiation of the stem cells, although challenges related with degradation, side effects, and high cost should be overcome. Owing to their unique physicochemical and biological properties, graphene-based nanomaterials have been widely used as scaffolds to manipulate stem cell growth and differentiation potential. Herein, we provide the most recent research progress in mesenchymal stem cells (MSCs) growth, differentiation and function utilizing graphene derivatives as extracellular scaffolds. The interaction of graphene derivatives in human and rat MSCs has been also evaluated. Graphene-based nanomaterials are biocompatible, exhibiting a great potential applicability in stem-cell-mediated regenerative medicine as they may promote the behaviour control of the stem cells. Finally, the challenges, prospects and future trends in the field are discussed.