Cytotoxic effects of acrylonitrile on human umbilical cord mesenchymal stem cells in vitro

The role of N-acetylcysteine in osteogenic microenvironment for bone tissue engineering

Bone defect is a common clinical symptom which can arise from various causes. Currently, bone tissue engineering has demonstrated positive therapeutic effects for bone defect repair by using seeding cells such as mesenchymal stem cells and precursor cells. N-acetylcysteine (NAC) is a stable, safe and highly bioavailable antioxidant that shows promising prospects in bone tissue engineering due to the ability to attenuate oxidative stress and enhance the osteogenic potential and immune regulatory function of cells. This review systematically introduces the antioxidant mechanism of NAC, analyzes the advancements in NAC-related research involving mesenchymal stem cells, precursor cells, innate immune cells and animal models, discusses its function using the classic oral microenvironment as an example, and places particular emphasis on the innovative applications of NAC-modified tissue engineering biomaterials. Finally, current limitations and future prospects are proposed, with the aim of providing inspiration for targeted readers in the field.

The influence of polyphenols on metabolic disorders caused by compounds released from plastics - Review

Persistent organic pollutants (POPs) released from plastics into water, soil and air are significant environmental and health problem. Continuous exposure of humans to these substances results not only from the slow biodegradation of plastics but also from their ubiquitous use as industrial materials and everyday products. Exposure to POPs may lead to neurodegenerative disorders, induce inflammation, hepatotoxicity, nephrotoxicity, insulin resistance, allergies, metabolic diseases, and carcinogenesis. This has spurred an increasing intense search for natural compounds with protective effects against the harmful components of plastics. In this paper, we discuss the current state of knowledge concerning the protective functions of polyphenols against the toxic effects of POPs: acrylonitrile, polychlorinated biphenyls, dioxins, phthalates and bisphenol A. We review in detail papers from the last two decades, analyzing POPs in terms of their sources of exposure and demonstrate how polyphenols may be used to counteract the harmful environmental effects of POPs. The protective effect of polyphenols results from their impact on the level and activity of the components of the antioxidant system, enzymes involved in the elimination of xenobiotics, and as a consequence - on the level of reactive oxygen species (ROS). Polyphenols present in daily diet may play a protective role against the harmful effects of POPs derived from plastics, and this interaction is related, among others, to the antioxidant properties of these compounds. To our knowledge, this is the first extensive review of in vitro and in vivo studies concerning the molecular mechanisms of interactions between selected environmental toxins and polyphenols.

Nrf2 played an important role in radiation protection effect of low-level laser exposed on umbilical cord mesenchymal stem cell

To investigate the protective function of low-level laser irradiation (LLLI) against ionizing irradiation and explore the molecular mechanism of photomodulation of Nrf2 protein, the impact of LLLI (635 nm, 5.7 J/cm²) before 2 Gy gamma ray radiation of radio-sensitive tissue hematopoietic stem cells was evaluated. As a result, reduced levels of reactive oxygen species and increased expression of antioxidant enzymes were detected. Moreover, increased expression of Nrf2 was observed after LLLI, whereas brusatol pretreatment before LLLI abolished this effect. In vivo, transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) was employed for therapy of hematopoietic function in an acute radiation sickness (H-ARS) mouse model, which was induced by 6-Gy ionizing irradiation; different hUC-MSC pretreatments including LLLI and Nrf2 RNAi were accounted for during experimental grouping. LLLI treatment of cells significantly increased the erythrocyte count and number of myelopoiesis clones (P < 0.05), but such improvements were reduced by Nrf2 RNAi pretreatment compared with cells transplanted without intervention. Therefore, LLLI may improve the radiation protection effect through molecular mechanisms related to the Nrf2 antioxidant pathway.

Peroxiredoxin 4 ameliorates amyloid beta oligomer-mediated apoptosis by inhibiting ER-stress in HT-22 hippocampal neuron cells

Alzheimer's disease (AD) is a neurodegenerative disorder caused by amyloid beta oligomers (AβO), which induce cell death by triggering oxidative stress and endoplasmic reticulum (ER) stress. Oxidative stress is regulated by antioxidant enzymes, including peroxiredoxins. Peroxiredoxins (Prx) are classified into six subtypes, based on their localization and cysteine residues, and protect cells by scavenging hydrogen peroxide (H₂O₂). Peroxiredoxin 4 (Prx4) is unique in being localized to the ER; however, whether Prx4 protects neuronal cells from AβO-induced toxicity remains unclear, although Prx4 expression is upregulated in AβO-induced oxidative stress and ER stress. In this study, we established HT-22 cells in which Prx4 was either overexpressed or silenced to investigate its role in AβO-induced toxicity. AβO-stimulation of HT-22 cells with overexpressed Prx4 caused decreases in both AβO-induced ROS and ER stress (followed by ER expansion). In contrast, AβO stimulation caused increases in both ROS and ER stress that were notably higher in HT-22 cells with silenced Prx4 expression than in HT-22 cells. Consequently, Prx4 overexpression decreased apoptotic cell death and ameliorated the AβO-induced increase in intracellular Ca²⁺. Therefore, we conclude that Prx4 has a protective effect against AβO-mediated oxidative stress, ER stress, and neuronal cell death. Furthermore, these results suggest that Prx4 may be a target for preventing AβO toxicity in AD. Graphical abstract .