Surface-Charge-Driven Ferroptosis and Mitochondrial Dysfunction Is Involved in Toxicity Diversity in the Marine Bivalve Exposed to Nanoplastics

Nanoplastics (NPs) pervade daily life, posing serious threats to marine ecosystems. Despite the crucial role that surface charge plays in NP effects, there is a substantial gap in our understanding of how surface charge influences NP toxicity. Herein, by exposing Ruditapes philippinarum (R. philippinarum) to both positively charged NPs (p-NPs) and negatively charged NPs (n-NPs) at environmentally relevant particle number levels for a duration of 35 days, we unequivocally demonstrate that both types of NPs had discernible impacts on the clams depending on their surface charge. Through transcriptomic and proteomic analyses, we unveiled the primary mechanisms behind p-NP toxicity, which stem from induced mitochondrial dysfunction and ferroptosis. In contrast, n-NPs predominantly stimulated innate immune responses, influencing salivary secretion and modulating the complement and coagulation cascades. Furthermore, in vitro tests on clam immune cells confirmed that internalized p-NPs triggered alterations in mitochondrial morphology, a decrease in membrane potential, and the initiation of ferroptosis. Conversely, n-NPs, to a certain extent, moderated the expression of genes related to immune responses, thus mitigating their adverse effects. Taken together, these findings indicate that the differential surface-charge-driven ferroptosis and mitochondrial dysfunction in clams play a critical role in the toxicity profile of NPs, providing an insightful reference for assessing the ecological toxicity associated with NPs

Surface-Charge-Driven Ferroptosis and Mitochondrial Dysfunction Is Involved in Toxicity Diversity in the Marine Bivalve Exposed to Nanoplastics

Nanoplastics (NPs) pervade daily life, posing serious threats to marine ecosystems. Despite the crucial role that surface charge plays in NP effects, there is a substantial gap in our understanding of how surface charge influences NP toxicity. Herein, by exposing Ruditapes philippinarum (R. philippinarum) to both positively charged NPs (p-NPs) and negatively charged NPs (n-NPs) at environmentally relevant particle number levels for a duration of 35 days, we unequivocally demonstrate that both types of NPs had discernible impacts on the clams depending on their surface charge. Through transcriptomic and proteomic analyses, we unveiled the primary mechanisms behind p-NP toxicity, which stem from induced mitochondrial dysfunction and ferroptosis. In contrast, n-NPs predominantly stimulated innate immune responses, influencing salivary secretion and modulating the complement and coagulation cascades. Furthermore, in vitro tests on clam immune cells confirmed that internalized p-NPs triggered alterations in mitochondrial morphology, a decrease in membrane potential, and the initiation of ferroptosis. Conversely, n-NPs, to a certain extent, moderated the expression of genes related to immune responses, thus mitigating their adverse effects. Taken together, these findings indicate that the differential surface-charge-driven ferroptosis and mitochondrial dysfunction in clams play a critical role in the toxicity profile of NPs, providing an insightful reference for assessing the ecological toxicity associated with NPs

CK levels of all groups.

<p>(n = 6 in each group. Values are mean (s.e.m.) * p<0.05 <i>versus</i> with sham, # p<0.05 versus with OLT group).</p

ALT and AST levels of all groups.

<p>(n = 6 in each group. Values are mean (s.e.m.) * p<0.05 <i>versus</i> with sham, # p<0.05 versus with OLT group).</p

Study design and RIC model of the study.

<p>A. Details and schematic representation of RIC protocol in this study. RIC rats were divided into three subgroup (10min×3, n = 6; 5min×3, n = 6; 1min×3, n = 6). B. Schematic diagram of RIC applied in this study. Standard tourniquet was used for ligature of the hindlimb with one 1kg weight in the end.</p

Expression of Pakt of all groups.

<p>Expression of Pakt of all groups.</p

Classification of RIC according to applied time point.

<p>Note, “P” stands for “perfusion”, “I” means “ischemic”, “R” means “reperfusion”.</p

Liver histopathological presentations of all groups (Haematoxylin and Eosin stain, original magnification ×200).

<p>Hepatocyte necrosis (arrow) and congestion of the sinusoids and central vein (white arrow head). (Values are mean (s.e.m.) * p<0.05 compared with sham, # p<0.05 compared with OLT group).</p

MDA and MPO levels of all groups.

<p>(n = 6 in each group. Values are mean (s.e.m.) * p<0.05 <i>versus</i> with sham, # p<0.05 versus with OLT group).</p