2,4‐dichlorophenoxyacetic acid induces ROS activation in NLRP3 inflammatory body‐induced autophagy disorder in microglia and the protective effect of Lycium barbarum polysaccharide

Abstract

The pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) exerts neurotoxic effects; however, its action mechanism remains unclear. Here, we used BV2 cells as a model and divided them into six groups: control group (serum-free medium), lipopolysaccharide (LPS) (1 μg/mL), 2,4-D (1.2 μmol/mL), Lycium barbarum polysaccharide (LBP; 300 μg/ mL LBP), LPS (1 μg/mL) + LBP (300 μg/mL), and 2,4-D (1.2 μmol/mL) + LBP (300 μg/mL) with dimethyl sulfoxide as the solvent. Our results showed that 2,4-D treatment decreased superoxide dismutase and glutathione peroxidase activities and increased malondialdehyde content. The percentage of microglial activation (coexpression of ionized calcium-binding adaptor protein-1 + CD68) in the LPS and 2,4-D groups and the levels of tumor necrosis factor alpha, interleukin (IL) 1 beta, IL-6, and IL-18 in the cell supernatant were increased. The protein and mRNA levels of Nod-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein, caspase-1, IL-1β, IL-18, and p62 increased, whereas those of LC3II/I and Beclin-1 decreased in the 2,4-D group. The protein expression and mRNA levels of NLRP3, cleaved caspase-1, IL-1β, IL-18, and p62 decreased significantly, whereas the protein expression and mRNA levels of LC3II/I and Beclin-1 increased in small interfering RNA of NLRP3-treated BV2 cells stimulated with 2,4-D and LPS. In conclusion, 2,4-D enhanced cell migration, promoted oxidative stress, induced excessive release of mitochondrial reactive oxygen species, promoted microglial cell activation, released inflammatory factors, activated NLRP3 inflammasomes, and inhibited autophagy.Meanwhile, LBP reduced inflammation and the release of mitochondrial reactive oxygen species, inhibited NLRP3 inflammasome activation, and regulated autophagy, thereby playing a neuroprotective role.

Pesticides as a risk factor for cognitive impairment: Natural substances are expected to become alternative measures to prevent and improve cognitive impairment

“…When the CNS is stimulated by the herbicide paraquat and the pyrethroid bifenthrin (BF) (27,28), microglia and astrocytes rapidly activate and proliferate, and a tissue repair process is initiated in response to this stimulus (29, 30). Activated microglia, astrocytes, and oxidized mtDNA can all stimulate the NLRP3 inflammasome (31), which is the core of inflammation and an important component of innate immunity. NLRP3 triggers the activation of caspase-1, which can induce apoptosis.…”

Effects of Lycium barbarum L. Polysaccharides on Vascular Retinopathy: An Insight Review

“…Caspase-1 helps pro-inflammatory cells secrete IL-1β and Il-18 to trigger inflammation, and the cleavage of GSDMD leads to cell lysis and swelling [ 80 , 81 ]. LBPs can reduce the inflammatory response and regulate autophagy, which has a neuroprotective effect [ 50 ]. In the light-induced apoptosis experiment of RPE cells, LBPs significantly enhanced cell viability and up-regulated the phosphorylation levels of Akt and mTOR proteins, thereby activating the PI3K/Akt/mTOR signaling pathway.…”

Progressive disruption of neurodevelopment by mid‐gestation exposure to lipopolysaccharides and the ameliorating effect of continuous alpha‐glycosyl isoquercitrin treatment

“…with the primary antibodies listed in Table S1, that is, glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 (Iba1), cluster of differentiation (CD) 68 and CD163 which are the glial cell markers 5,34 ; GFAP, SRY-box transcription factor 2 (SOX2), Tbox brain protein 2 (TBR2), doublecortin (DCX), tubulin, beta 3 class III (TUBB3), and neuronal nuclei (NeuN), which are the marker proteins of hippocampal granule cell lineage subpopulations 15,[35][36][37] ; proliferating cell nuclear antigen (PCNA), a cell proliferation marker; calbindin-D-28K (CALB1), calbindin-D-29K (CALB2), glutamic acid decarboxylase 67 (GAD67), parvalbumin (PVALB), reelin (RELN), and somatostatin (SST), which are the GABAergic interneuron markers 19,38 ; Fos proto-oncogene, AP-1 transcription factor subunit (FOS), activityregulated cytoskeleton-associated protein (ARC), cyclooxygenase-2 (COX2) and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2; phosphorylated p44/p42 MAP kinase), which are the markers involved in synaptic plasticity. [39][40][41] Immunohistochemical detection of the antigens was conducted employing an Avidin-Biotin Complex method.…”