Polystyrene nanoplastics promote CHIP-mediated degradation of tight junction proteins by activating IRE1α/XBP1s pathway in mouse Sertoli cells.

Microplastics (MPs) and nanoplastics (NPs) widely exist in human living environment and enter the body through water, food chain and breathing. Several studies have shown that MPs or NPs disrupt the blood-testis barrier in rodents. However, the molecular mechanism by which MPs and NPs damage the blood-testis barrier remains unclear. In the present study, our aim was to investigate the molecular mechanism of the destruction of blood-testis barrier induced by polystyrene (PS)-NPs. Mice were treated with 50 µg/kg·day PS-NPs by tail vein injection once daily for two consecutive days. The results showed that PS-NPs exposure significantly decreased the levels of tight junction (TJ) proteins ZO-2, occludin and claudin-11 in testis of mice. In vitro, we used TM4 Sertoli cells to explore the underlying mechanism of the decrease in TJ proteins induced by PS-NPs. We found that PS-NPs activated IRE1α and induced its downstream XBP1 splicing, which in turn elevated the expression of the E3 ubiquitin ligase CHIP, then CHIP triggers proteasomal degradation of ZO-2, occludin, and claudin-11 proteins. Our findings suggest that IRE1α/XBP1s/CHIP pathway is a pivotal mechanism of TJ proteins degradation induced by PS-NPs in mouse Sertoli cells. In conclusion, our results reveal that the degradation of TJ proteins is one of the mechanisms of blood-testis barrier destruction caused by acute exposure to PS-NPs.

Spatial-Temporal Footprints Assessment and Driving Mechanism of China Household Diet Based on CHNS.

Food consumption is closely associated with resource consumption and environmental sustainability. An unreasonable dietary pattern would cause great pressure or damage to resources and the environment. It is particularly important to reduce the negative impact of household food consumption on resources and the environment while simultaneously ensuring people's nutrient intake and health. This study applied the China Health and Nutrition Survey (CHNS) database to quantitatively study the spatial-temporal analysis of multiple footprints of household food consumption at multiple scales and explored the driving mechanism of the multiple footprints. The results showed that, except land footprint (LF), the other four types of footprints all decreased at varying degrees; the water footprint (WF), carbon footprint (CF), nitrogen footprint (NF) and energy footprint (EF) decreased by 18.24%, 17.82%, 12.03% and 20.36%, respectively, from 2000 to 2011; multiple footprints of food consumption of household in Guizhou was the highest among the 12 provinces involved in the study; this shows that resource consumption (water, energy and land resource) and environmental influences (CO2 emissions and nitrogen emissions) brought by food consumption of per household in Guizhou are much greater than in other provinces, which has a negative influence on sustainable development; by analyzing the driving factors of multiple footprints, it is shown that nutrient intake, household attributes, educational level and health conditions were significantly correlated to multiple footprints. Among them, nutrient intake has greater impact on the multiple footprints of Chinese household food consumption. By comparing multiple footprints of different dietary patterns, it was found that the current Chinese dietary pattern would cause excessive resource consumption, which would bring more pressure on resources and the environment. Adjusting household living habits would possibly reverse the unsustainable situation, such as reducing the consumption of animal-derived foods and adjusting the dietary pattern of households with a higher educational level and income status. Chinese Dietary Guidelines 2016 has better sustainability; the promotion of this dietary pattern across the country would help China to relieve the pressure on resources and environment from the consumer side, promoting the realization of sustainable development.