Mechanism of KAT2A regulation of H3K36ac in manganese-induced oxidative damage to mitochondria in the nervous system and intervention by curcumin

Excessive exposure to manganese in the environment or workplace is strongly linked to neurodegeneration and cognitive impairment, but the precise pathogenic mechanism and preventive measures are still not fully understood. The study aimed to investigate manganese -induced oxidative damage in the nervous system from an epigenetic perspective, focusing on the H3K36ac-dependent antioxidant pathway. Additionally, it sought to examine the potential of curcumin in preventing manganese-induced oxidative damage. Histopathology and transmission electron microscopy revealed that apoptosis and necrosis of neurons and mitochondrial ultrastructure damage were observed in the striatum of manganese-exposed rats. manganese suppressed the expression of mitochondrial antioxidant genes, leading to oxidative damage in the rats' striatum and SH-SY5Y cells. With higher doses of manganese, levels of histone acetyltransferase lysine acetyltransferase 2 A (KAT2A) expression and H3K36ac level decreased. ChIP-qPCR confirmed that H3K36ac enrichment in the promoter regions of antioxidant genes SOD2, PRDX3, and TXN2 was reduced in SH-SY5Y cells after manganese exposure, leading to decreased expression of these genes. Overexpression of KAT2A confirms that it attenuates manganese-induced mitochondrial oxidative damage by regulating H3K36ac levels, which in turn controls the expression of antioxidant genes SOD2, PRDX3, and TXN2 in the manganese-exposed cell model. Furthermore, curcumin might control H3K36ac levels by influencing KAT2A expression, boosting antioxidant genes expression, and reducing manganese-induced mitochondrial oxidative damage. In conclusion, the regulation of mitochondrial oxidative stress by histone acetylation may be an important mechanism of manganese-induced neurotoxicity. This regulation could be achieved by reducing the level of H3K36ac near the promoter region of mitochondrial-associated antioxidant genes via KAT2A. Curcumin mitigates manganese-induced oxidative damage in mitochondria and plays a crucial protective role in manganese-induced oxidative injury in the nervous system.

Advances in the study of silica nanoparticles in lung diseases

Silicon dioxide nanoparticles (SiNPs) are one of the major forms of silicon dioxide and are composed of the most-abundant compounds on earth. Based on their excellent properties, SiNPs are widely used in food production, synthetic processes, medical diagnostics, drug delivery, and other fields. The mass production and wide application of SiNPs increases the risk of human exposure to SiNPs. In the workplace and environment, SiNPs mainly enter the human body through the respiratory tract and reach the lungs; therefore, the lungs are the most important and most toxicologically affected target organ of SiNPs. An increasing number of studies have shown that SiNP exposure can cause severe lung toxicity. However, studies on the toxicity of SiNPs in ex vivo and in vivo settings are still in the exploratory phase. The molecular mechanisms underlying the lung toxicity of SiNPs are varied and not yet fully understood. As a result, this review summarizes the possible mechanisms of SiNP-induced lung toxicity, such as oxidative stress, endoplasmic reticulum stress, mitochondrial damage, and cell death. Moreover, this study provides a summary of the progression of diseases caused by SiNPs, thereby establishing a theoretical basis for future studies on the mechanisms of SiNP-induced lung toxicity.