Suppression of Mitochondria-Related Bioenergetics Collapse and Redox Impairment by Tanshinone I, a Diterpenoid Found in Salvia miltiorrhiza Bunge (Danshen), in the Human Dopaminergic SH-SY5Y Cell Line Exposed to Chlorpyrifos

The application of human-derived cell lines in neurotoxicity studies of environmental pollutants

As industrial and societal advancements progress, an increasing number of environmental pollutants linked to human existence have been substantiated to elicit neurotoxicity and developmental neural toxicity. For research in this field, human-derived neural cell lines have become excellent in vitro models. This study examines the utilization of immortalized cell lines, specifically the SH-SY5Y human neuroblastoma cell line, and neural cells derived from human pluripotent stem cells, in the investigation of neurotoxicity and developmental neural toxicity caused by environmental pollutants. The study also explores the culturing techniques employed for these cell lines and provides an overview of the standardized assays used to assess various biological endpoints. The environmental pollutants involved include a variety of organic compounds, heavy metals, and microplastics. The utilization of cell lines derived from human sources holds significant significance in elucidating the neurotoxic effects of environmental pollutants and the underlying mechanisms. Finally, we propose the possibility of improving the in vitro model of the human nervous system and the toxicity detection methods.

The isothiocyanate sulforaphane prevents mitochondrial impairment and neuroinflammation in the human dopaminergic SH-SY5Y and in the mouse microglial BV2 cells: role for heme oxygenase-1

Sulforaphane (SFN) promotes protective effects in different cell types. Nonetheless, it remains to be clarified by which mechanism SFN exerts benefits in mammalian cells. Mitochondria are a major source of adenosine triphosphate (ATP) and reactive species in nucleated cells. Mitochondrial impairment result in cellular redox biology disruption, bioenergetic status collapse, and inflammation. Evidence suggest that mitochondrial dysfunction plays a role in neurological disorders. Since a cure was not discovered yet to some of these diseases, investigating strategies to promote mitochondrial protection is pharmacologically relevant and may improve life quality of patients suffering from these maladies. Natural molecules, such as SFN, are potent inducers of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and, consequently, stimulate the expression of genes whose products, such as heme oxygenase-1 (HO-1), induce cytoprotective actions in mammalian tissues. In this work, we investigated whether SFN (5 µM) would be capable to prevent the dysfunctions caused by chlorpyrifos (CPF) on the human dopaminergic SH-SY5Y cells. Moreover, we examined the effects of a pretreatment with SFN at the same concentration on the mouse microglial BV2 cells stimulated by lipopolysaccharide (LPS) in an experimental model of neuroinflammation. SFN prevented the mitochondrial impairment and the neuroinflammation caused by the chemical stressors in both cell types. Inhibition of heme oxygenase-1 (HO-1) suppressed the mitochondrial protection and anti-inflammatory action afforded by SFN in this experimental model. Overall, SFN promoted cytoprotection by a mechanism dependent on the HO-1 enzyme in the SH-SY5Y and BV2 cells.

The SH-SY5Y human neuroblastoma cell line, a relevant in vitro cell model for investigating neurotoxicology in human: focus on organic pollutants

Investigation of the toxicity triggered by chemicals on the human brain has traditionally relied on approaches using rodent in vivo models and in vitro cell models including primary neuronal cultures and cell lines from rodents. The issues of species differences between humans and rodents, the animal ethical concerns and the time and cost required for neurotoxicity studies on in vivo animal models, do limit the use of animal-based models in neurotoxicology. In this context, human cell models appear relevant in elucidating cellular and molecular impacts of neurotoxicants and facilitating prioritization of in vivo testing. The SH-SY5Y human neuroblastoma cell line (ATCC® CRL-2266^TM) is one of the most used cell lines in neurosciences, either undifferentiated or differentiated into neuron-like cells. This review presents the characteristics of the SH-SY5Y cell line and proposes the results of a systematic review of literature on the use of this in vitro cell model for neurotoxicity research by focusing on organic environmental pollutants including pesticides, 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD), flame retardants, PFASs, parabens, bisphenols, phthalates, and PAHs. Organic environmental pollutants are widely present in the environment and increasingly known to cause clinical neurotoxic effects during fetal & child development and adulthood. Their effects on cultured SH-SY5Y cells include autophagy, cell death (apoptosis, pyroptosis, necroptosis, or necrosis), increased oxidative stress, mitochondrial dysfunction, disruption of neurotransmitter homeostasis, and alteration of neuritic length. Finally, the inherent advantages and limitations of the SH-SY5Y cell model are discussed in the context of chemical testing.

A Pretreatment with Isoorientin Attenuates Redox Disruption, Mitochondrial Impairment, and Inflammation Caused by Chlorpyrifos in a Dopaminergic Cell Line: Involvement of the Nrf2/HO-1 Axis

The C-glucosyl flavone isoorientin (ISO) is obtained by humans from the diet and exhibits several cytoprotective effects, as demonstrated in different experimental models. However, it was not previously shown whether ISO would be able to prevent mitochondrial impairment in cells exposed to a chemical stressor. Thus, we treated the human neuroblastoma SH-SY5Y cells with ISO (0.5-20 µM) for 18 h before a challenge with chlorpyrifos (CPF) at 100 µM for additional 24 h. We observed that ISO prevented the CPF-induced lipid peroxidation and protein carbonylation and nitration in the membranes of mitochondria extracted from CPF-treated cells. ISO also attenuated the CPF-elicited increase in the production of reactive species in this experimental model. Moreover, ISO prevented the CPF-induced disruption in the activity of components of the oxidative phosphorylation (OXPHOS) system in the SH-SY5Y cells. ISO also promoted an anti-inflammatory action in the cells exposed to CPF. CPF caused a decrease in the activity of the enzyme heme oxygenase-1 (HO-1), a cytoprotective agent. On the other hand, ISO upregulated HO-1 activity in SH-SY5Y cells. Inhibition of HO-1 by zinc protoporphyrin-IX (ZnPP-IX) suppressed the cytoprotection induced by ISO in the CPF-treated cells. Besides, silencing of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) abolished the ISO-induced HO-1 upregulation and mitochondrial benefits induced by this flavone on the CPF-challenged cells. Thus, ISO protected mitochondria of the CPF-treated cells by an Nrf2/HO-1-dependent fashion in the SH-SY5Y cells.