Hydrogen peroxide induces progranulin expression to control neurite outgrowth in HT22 cells

Measurement of cellular MDA content through MTBE-extraction based TBA assay by eliminating cellular interferences

Malondialdehyde (MDA) has long been served as a crucial indicator for assessing cellular oxidative stress levels. In this study, we introduce a new approach to determine cellular MDA levels based on a methyl tert-butyl ether (MTBE) extraction, aimed at eliminating interferences from cellular components during thiobarbituric acid (TBA) derivatization of MDA. By leveraging the effective MTBE extraction, we identified that the determination of the MDA-TBA adduct formed from the MTBE extraction layer can effectively eliminate the interferences from cellular proteins and metabolites. This method demonstrated acceptable linearity and precision in cellular samples and showed significant differences in H2O2 treated cellular oxidative stress models. The MTBE extraction-based MDA-TBA approach provides a reliable, cost-effective, and feasible method to determine cellular MDA levels using batch microplate reader approach for the assessment of cellular oxidative stress.

Neuronal NADPH oxidase is required for neurite regeneration of Aplysia bag cell neurons

NADPH oxidase (Nox), a major source of reactive oxygen species (ROS), is involved in neurodegeneration after injury and disease. Nox is expressed in both neuronal and non-neuronal cells and contributes to an elevated ROS level after injury. Contrary to the well-known damaging effect of Nox-derived ROS in neurodegeneration, recently a physiological role of Nox in nervous system development including neurogenesis, neuronal polarity, and axonal growth has been revealed. Here, we tested a role for neuronal Nox in neurite regeneration following mechanical transection in cultured Aplysia bag cell neurons. Using a novel hydrogen peroxide (H2 O2 )-sensing dye, 5'-(p-borophenyl)-2'-pyridylthiazole pinacol ester (BPPT), we found that H2 O2 levels are elevated in regenerating growth cones following injury. Redistribution of Nox2 and p40phox in the growth cone central domain suggests Nox2 activation after injury. Inhibiting Nox with the pan-Nox inhibitor celastrol reduced neurite regeneration rate. Pharmacological inhibition of Nox is correlated with reduced activation of Src2 tyrosine kinase and F-actin content in the growth cone. Taken together, these findings suggest that Nox-derived ROS regulate neurite regeneration following injury through Src2-mediated regulation of actin organization in Aplysia growth cones.