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Decomposition of plastic materials into minuscule particles and their long-term uptake pose increasing concerns on environmental sustainability and biosafety. Besides common cell viability and cytotoxicity evaluations, how plastic nanoparticles interfere with different stress response pathways and affect cellular fitness has been less explored. Here, we provided the first piece of evidence to demonstrate plastic nanoparticles potentially can deteriorate proteome stability, compromise cellular protein homeostasis, and consequently cause global proteome misfolding and aggregation. Polystyrene (PS) nanoparticles of different sizes and surface charges were exploited as model plastic materials. In cell lysate and human blood plasma, naked PS nanoparticles with hydrophobic surface deteriorated proteome thermodynamic stability and exaggerated its aggregation propensity. While no cell viability ablation was observed in cells treated with PS nanoparticles up to 200 μg·mL−1, global proteome aggregation and stress was detected by a selective proteome aggregation sensor. Further proteomics analysis revealed how protein homeostasis network was remodeled by positively charged PS nanoparticles via differential expression of key proteins to counteract proteome stress. In mice model, size-dependent liver accumulation of positively charged PS nanoparticles induced hepatocellular proteome aggregation and compromised protein homeostasis network capacity that were invisible to standard alanine transaminase and aspartate transaminase (ALT/AST) liver function as-say and histology. Meanwhile, long-term liver accumulation of plastic nanoparticles deteriorated liver metabolism and saturated liver detoxification capacity of overdosed acetaminophen. This work highlighted the impact of nanoplastics on cellular proteome integrity and cellular fitness that are invisible to current biochemical assays and clinical tests.

The successful application of probiotics in food industry depends on the use of good cryoprotectants. This paper was aimed to evaluate protective effects of enzymatic hydrolysis products of different degrees of pomelo peel cellulose (EHPC) on Lactobacillus plantarum during freeze-drying process. The data showed that in contrast to trehalose, the survival rate of L. plantarum was increased obviously under the optimal composite cryoprotectants, which consisted of trehalose and EHPC for 2 h with the mass ratio of 8:2. In addition, the morphology, water-related indices, glass transition temperature (Tg) and cell membrane integrity of lyophilized L. plantarum powder were also evaluated. The results showed that the water content of L. plantarum prepared by the optimal composite cryoprotectants was lower, which was in a reasonable range and conducive to subsequent storage; the Tg and cell membrane integrity were significantly improved. Furthermore, the macromolecular fibers of composite cryoprotectants provided a good habitat and attachment space for L. plantarum, and the sheet fibers with large area acted as a physical barrier to prevent the damage to cells from adverse external environment. The composite cryoprotectants from this study could be considered for industrial development of probiotics.