MDM2 upregulation induces mitophagy deficiency via Mic60 ubiquitination in fetal microglial inflammation and consequently neuronal DNA damage caused by exposure to ZnO-NPs during pregnancy

Mitophagy and its regulatory mechanisms in the biological effects of nanomaterials

Mitophagy is a selective cellular process critical for the removal of damaged mitochondria. It is essential in regulating mitochondrial number, ensuring mitochondrial functionality, and maintaining cellular equilibrium, ultimately influencing cell destiny. Numerous pathologies, such as neurodegenerative diseases, cardiovascular disorders, cancers, and various other conditions, are associated with mitochondrial dysfunctions. Thus, a detailed exploration of the regulatory mechanisms of mitophagy is pivotal for enhancing our understanding and for the discovery of novel preventive and therapeutic options for these diseases. Nanomaterials have become integral in biomedicine and various other sectors, offering advanced solutions for medical uses including biological imaging, drug delivery, and disease diagnostics and therapy. Mitophagy is vital in managing the cellular effects elicited by nanomaterials. This review provides a comprehensive analysis of the molecular mechanisms underpinning mitophagy, underscoring its significant influence on the biological responses of cells to nanomaterials. Nanoparticles can initiate mitophagy via various pathways, among which the PINK1-Parkin pathway is critical for cellular defense against nanomaterial-induced damage by promoting mitophagy. The role of mitophagy in biological effects was induced by nanomaterials, which are associated with alterations in Ca2+ levels, the production of reactive oxygen species, endoplasmic reticulum stress, and lysosomal damage.

Molecular mechanisms of zinc oxide nanoparticles neurotoxicity

Zinc oxide nanoparticles (ZnONPs) are widely used in industry and biomedicine. A growing body of evidence demonstrates that ZnONPs exposure may possess toxic effects to a variety of tissues, including brain. Therefore, the objective of the present review was to summarize existing evidence on neurotoxic effects of ZnONPs and discuss the underlying molecular mechanisms. The existing laboratory data demonstrate that both in laboratory rodents and other animals ZnONPs exposure results in a significant accumulation of Zn in brain and nervous tissues, especially following long-term exposure. As a result, overexposure to ZnONPs causes oxidative stress and cell death, both in neurons and glial cells, by induction of apoptosis, necrosis and ferroptosis. In addition, ZnONPs may induce neuroinflammation through the activation of nuclear factor kappa B (NF-κB), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), and lipoxygenase (LOX) signaling pathways. ZnONPs exposure is associated with altered cholinergic, dopaminergic, serotoninergic, as well as glutamatergic and γ-aminobutyric acid (GABA)-ergic neurotransmission, thus contributing to impaired neuronal signal transduction. Cytoskeletal alterations, as well as impaired autophagy and mitophagy also contribute to ZnONPs-induced brain damage. It has been posited that some of the adverse effects of ZnONPs in brain are mediated by altered microRNA expression and dysregulation of gut-brain axis. Furthermore, in vivo studies have demonstrated that ZnONPs exposure induced anxiety, motor and cognitive deficits, as well as adverse neurodevelopmental outcome. At the same time, the relevance of ZnONPs-induced neurotoxicity and its contribution to pathogenesis of neurological diseases in humans are still unclear. Further studies aimed at estimation of hazards of ZnONPs to human brain health and the underlying molecular mechanisms are warranted.

Copper induced cytosolic escape of mitochondrial DNA and activation of cGAS-STING-NLRP3 pathway-dependent pyroptosis in C8-D1A cells

Copper, a vital mineral nutrient, possesses redox qualities that make it both beneficial and toxic to organisms. Excessive environmental copper exposure can result in neurological damage and cognitive decline in humans. Astrocytes, the predominant glial cells in the brain, are particularly vulnerable to pollutants, but the mechanism of copper-induced damage to astrocytes remains elusive. The aim of this study was to determine the role of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway in initiating NLRP3 inflammasome-induced astrocyte pyroptosis and chronic inflammation under conditions of copper overload. Our findings indicated that copper exposure elevated mitochondrial ROS (mtROS) levels, resulting in mitochondrial damage in astrocytes. This damage caused the release of mitochondrial DNA (mtDNA) into the cytoplasm, which subsequently activated the cGAS-STING pathway. This activation resulted in interactions between STING and NLRP3 proteins, facilitating the assembly of the NLRP3 inflammasome and inducing pyroptosis. Furthermore, depletion of mtROS mitigated copper-induced mitochondrial damage in astrocytes and reduced mtDNA leakage. Pharmacological inhibition of STING or STING transfection further reversed copper-induced pyroptosis and the inflammatory response. In conclusion, this study demonstrated that the leakage of mtDNA into the cytoplasm and the subsequent activation of the cGAS-STING-NLRP3 pathway may be potential mechanisms underlying copper-induced pyroptosis in astrocytes. These findings provided new insights into the toxicity of copper.

Honeycomb Bionic Graphene Oxide Quantum Dot/Layered Double Hydroxide Composite Nanocoating Promotes Osteoporotic Bone Regeneration via Activating Mitophagy

Abnormal osteogenic and remodeling microenvironment due to osteoblast apoptosis are the primary causes of delayed fracture healing in osteoporotic patients. Magnesium (Mg) alloys exhibit biodegradability and appropriate elastic moduli for bone defects in osteoporosis, but the effect on the local bone remodeling disorder is still insufficient. Inspired by the "honeycomb," layered double hydroxide (LDH) with regular traps with graphene oxide quantum dots (GOQDs) inlayed is constructed by pulsed electrodeposition to generate GOQD/LDH composite nanocoatings on the surfaces of Mg alloy substrates. The honeycomb bionic multi-layer stereoscopic structure shows good regulation of the degradation of Mg alloy for the support of healing time required for osteoporotic bone defect. Within its lattice, the local microenvironment conducive to osteogenesis is provided by both the rescue effect of GOQD and LDH. The osteoblast apoptosis is rescued due to the activation of mitophagy to clear dysfunctional mitochondria, where the upregulation of BNIP3 phosphorylation played a key role. The osteoporotic rat model of femoral defects confirmed the improvement of bone regeneration and osseointegration of GOQD/LDH coating. In summary, honeycomb bionic composite nanocoatings with controllable degradation and excellent pro-osteogenic performance demonstrated a promising design strategy on Mg alloy implants in the therapy of osteoporotic bone defects.

Zinc oxide nanoparticles disrupt the mammary epithelial barrier via Z-DNA binding protein 1-triggered PANoptosis

Lactation women, a highly concerned demographic in society, face health risks that deserve attention. Zinc oxide nanoparticles (ZnO NPs) are widely utilized in food and daily products due to their excellent physicochemical properties, leading to the potential exposure of lactating women to ZnO NPs. Hence, assessing the potential risks associated with ZnO NP exposure during lactation is critical. While studies have confirmed that exposure to ZnO NPs during lactation can induce toxic responses in multiple organs through blood circulation, the effects of lactational exposure on mammary tissue remain unclear. This research investigated the impairment of mammary tissue induced by ZnO NPs and its potential mechanisms. Through administering multiple injections of ZnO NPs into the tail vein of lactating ICR mice, our study revealed that ZnO NPs can deposit in the mammary tissues, downregulating key components of mammary epithelial barrier such as ZO-1, occludin, and claudin-3. In vivo, we also found that ZnO NPs can simultaneously induce apoptosis, necroptosis, and pyroptosis, called PANoptosis. Additionally, using EpH4-Ev cells to simulate an in vitro mammary epithelial barrier model, we observed that ZnO NPs effectively disrupted the integrity of mammary epithelial barrier and induced PANoptosis. Furthermore, we confirmed that PANoptosis was responsible for the mammary epithelial barrier disruption induced by ZnO NPs. Moreover, we identified that ZBP1 was the primary mechanism of ZnO NPs inducing PANoptosis. These discoveries are designed to enhance our comprehension of the mechanisms underlying mammary epithelial barrier disruption caused by ZnO NPs, and we aim to highlight the potential hazards associated with daily usage and therapeutic exposure to ZnO NPs during lactation.

Graphene Quantum Dots Reduce Hypertrophic Scar by Inducing Myofibroblasts To Be a Quiescent State

Contrary to the initial belief that myofibroblasts are terminally differentiated cells, myofibroblasts have now been widely recognized as an activation state that is reversible. Therefore, strategies targeting myofibroblast to be a quiescent state may be an effective way for antihypertrophic scar therapy. Graphene quantum dots (GQDs), a novel zero-dimensional and carbon-based nanomaterial, have recently garnered significant interest in nanobiomedicine, owing to their excellent biocompatibility, tunable photoluminescence, and superior physiological stability. Although multiple nanoparticles have been used to alleviate hypertrophic scars, a GQD-based therapy has not been reported. Our in vivo studies showed that GQDs exhibited significant antiscar efficacy, with scar appearance improvement, collagen reduction and rearrangement, and inhibition of myofibroblast overproliferation. Further in vitro experiments revealed that GQDs inhibited α-SMA expression, collagen synthesis, and cell proliferation and migration, inducing myofibroblasts to become quiescent fibroblasts. Mechanistic studies have demonstrated that the effect of GQDs on myofibroblast proliferation blocked cell cycle progression by disrupting the cyclin-CDK-E2F axis. This study suggests that GQDs, which promote myofibroblast-to-fibroblast transition, could be a novel antiscar nanomedicine for the treatment of hypertrophic scars and other types of pathological fibrosis.

Zinc oxide nanoparticles induces cell death and consequently leading to incomplete neural tube closure through oxidative stress during embryogenesis

The implementation of Zinc oxide nanoparticles (ZnO NPs) raises concerns regarding their potential toxic effects on human health. Although more and more researches have confirmed the toxic effects of ZnO NPs, limited attention has been given to their impact on the early embryonic nervous system. This study aimed to explore the impact of exposure to ZnO NPs on early neurogenesis and explore its underlying mechanisms. We conducted experiments here to confirm the hypothesis that exposure to ZnO NPs causes neural tube defects in early embryonic development. We first used mouse and chicken embryos to confirm that ZnO NPs and the Zn2+ they release are able to penetrate the placental barrier, influence fetal growth and result in incomplete neural tube closure. Using SH-SY5Y cells, we determined that ZnO NPs-induced incomplete neural tube closure was caused by activation of various cell death modes, including ferroptosis, apoptosis and autophagy. Moreover, dissolved Zn2+ played a role in triggering widespread cell death. ZnO NPs were accumulated within mitochondria after entering cells, damaging mitochondrial function and resulting in the over production of reactive oxygen species, ultimately inducing cellular oxidative stress. The N-acetylcysteine (NAC) exhibits significant efficacy in mitigating cellular oxidative stress, thereby alleviating the cytotoxicity and neurotoxicity brought about by ZnO NPs. These findings indicated that the exposure of ZnO NPs in early embryonic development can induce cell death through oxidative stress, resulting in a reduced number of cells involved in early neural tube closure and ultimately resulting in incomplete neural tube closure during embryo development. The findings of this study could raise public awareness regarding the potential risks associated with the exposure and use of ZnO NPs in early pregnancy.

Zinc oxide nanoparticles damage the prefrontal lobe in mouse: Behavioral impacts and key mechanisms

Zinc Oxide nanoparticles (ZnO NPs) have dualistic properties due to their advantage and toxicity. However, the impact and mechanisms of ZnO NPs on the prefrontal lobe have limited research. This study investigates the behavioral changes following exposure to ZnO NPs (34 mg/kg, 30 days), integrating multiple behaviors and bioinformatics analysis to identify critical factors and regulatory mechanisms. The essential differentially expressed genes (DEGs) were identified, including ORC1, DSP, AADAT, SLITRK6, and STEAP1. Analysis of the DEGs based on fold change reveals that ZnO NPs primarily regulate cell survival, proliferation, and apoptosis in neural cells, damaging the prefrontal lobe. Moreover, disruption of cell communication, mineral absorption, and immune pathways occurs. Gene set enrichment analysis (GSEA) further shows enrichment of behavior, neuromuscular process, signal transduction in function, synapses-related, cAMP signaling, and immune pathways. Furthermore, alternative splicing (AS) genes highlight synaptic structure/function, synaptic signal transduction, immune responses, cell proliferation, and communication.

Developing a Selection Framework for Zinc Ion-Based Biomaterial Design: Guided by the Biosafety Assessment of ZIF-8 and ZnO

In recent years, nanomaterials have gained widespread use in the biomedical field, with ZIF-8 and ZnO emerging as promising candidates due to their remarkable performance in osteogenesis, angiogenesis, and antimicrobial therapy. However, before advancing these nanomaterials for clinical applications, it is imperative to evaluate their biocompatibility. In particular, comparing nanomaterials with similar biomedical functions is crucial for identifying the most suitable nanomaterials for further development and market entry. Our study aimed to compare the biocompatibility of nano-ZIF-8 and nano-ZnO under the same conditions. We found that nano-ZIF-8 exhibited lower toxicity both in vitro and in vivo compared to nano-ZnO. To gain insights into the underlying mechanisms responsible for this difference, we conducted further experiments to investigate lysosome damage, mitochondrial change, and the occurrence of ferroptosis. Additionally, we performed transcriptome sequencing to analyze the expression of relevant genes, thereby providing robust validation for our findings. In summary, our study highlighted the importance of evaluating nanomaterials with similar biomedical effects. Through this comparative study, we have not only shed light on the superior biocompatibility of nano-ZIF-8 over nano-ZnO, but also contributed valuable insights and methodological references for future material screening endeavors. Ultimately, our study served as a stepping stone toward the development of safer and more effective nanomaterials for various biomedical applications.

Beyond the promise: Exploring the complex interactions of nanoparticles within biological systems

The exploration of nanoparticle applications is filled with promise, but their impact on the environment and human health raises growing concerns. These tiny environmental particles can enter the human body through various routes, such as the respiratory system, digestive tract, skin absorption, intravenous injection, and implantation. Once inside, they can travel to distant organs via the bloodstream and lymphatic system. This journey often results in nanoparticles adhering to cell surfaces and being internalized. Upon entering cells, nanoparticles can provoke significant structural and functional changes. They can potentially disrupt critical cellular processes, including damaging cell membranes and cytoskeletons, impairing mitochondrial function, altering nuclear structures, and inhibiting ion channels. These disruptions can lead to widespread alterations by interfering with complex cellular signaling pathways, potentially causing cellular, organ, and systemic impairments. This article delves into the factors influencing how nanoparticles behave in biological systems. These factors include the nanoparticles' size, shape, charge, and chemical composition, as well as the characteristics of the cells and their surrounding environment. It also provides an overview of the impact of nanoparticles on cells, organs, and physiological systems and discusses possible mechanisms behind these adverse effects. Understanding the toxic effects of nanoparticles on physiological systems is crucial for developing safer, more effective nanoparticle-based technologies.

Blocked Autophagy is Involved in Layered Double Hydroxide-Induced Repolarization and Immune Activation in Tumor-Associated Macrophages

Tumor-associated macrophages (TAMs) are important immune cells in the tumor microenvironment (TME). The polar plasticity of TAMs makes them important targets for improving the immunosuppressive microenvironment of tumors. The previous study reveals that layered double hydroxides (LDHs) can effectively promote the polarization of TAMs from the anti-inflammatory M2 type to the pro-inflammatory M1 type. However, their mechanisms of action remain unexplored. This study reveals that LDHs composed of different cations exhibit distinct abilities to regulate the polarity of TAMs. Compared to Mg-Fe LDH, Mg-Al LDH has a stronger ability to promote the repolarization of TAMs from M2 to M1 and inhibit the formation of myeloid-derived suppressor cells (MDSCs). In addition, Mg-Al LDH restrains the growth of tumors in vivo and promotes the infiltration of activated immune cells into the TME more effectively. Interestingly, Mg-Al LDH influences the autophagy of TAMs; this negatively correlates with the pro-inflammatory ability of TAMs. Therefore, LDHs exert their polarization ability by inhibiting the autophagy of TAMs, and this mechanism might be related to the ionic composition of LDHs. This study lays the foundation for optimizing the performance of LDH-based immune adjuvants, which display excellent application prospects for tumor immunotherapy.