Crosstalk between Autophagy and Nanomaterials: Internalization, Activation, Termination

Abstract

NMs, SiO 2 -based NMs, lipid-based NMs, polymer-based NMs, polyethylene glycol (PEG)-based NMs, and other types NMs. Alternatively, according to the physical and chemical properties of NMs, they can be classified into soft NMs, referring to lipidor polymer-based NMs, and hard NMs such as mental-or carbon-based NMs.With the development of nanotechnology, these materials have been widely applied in various fields. [3] For example, ZnO nanoparticles (NPs) can serve as antimicrobial agents; [4] TiO 2 NPs are used in sunscreen lotions; [5] lipid/polymeric-based NPs are applied in drug/gene delivery; [6] QDs are used as florescent probes; [7] and magnetic NPs are applied in magnetic resonance imaging. [8] The NMs not only effectively enhance cellular and subcellular targeting of drugs and the effect of imaging, but also rise the attention on the importance of affirming the effect of NMs on biological systems. It has been recognized that NMs are capable of modulating autophagy. The modulation of NMs on autophagy may be beneficial, since the combinative effect of the NMs' features and autophagy functions is capable of enhancing the accuracy of diagnosis and efficiency of therapies. For example, AgNPs could be a fascinating tool in infections and antimicrobial immunity in that the NM-phagy can modulate the antiviral/antibacterial defenses. [9] In this process, AgNPs lead to the disorganization of mitochondrial network and contribute to the modulation of autophagy (both Rab9-dependent alternative autophagy and Atg-5-dependent classical autophagy) by blocking the autophagic flux. Additionally, AgNPs can reduce the production of CCL-5 and interferon (IFN)-β in influenza-infected cells through the Rab9-dependent alternative autophagy.Autophagy, a "self-digestion" biological process of cellular degradation, is induced when cells are subjected to unfavorable factors, including starvation or drug treatments, accumulation of the damaged organelles, and misfolded proteins. The autophagic process refers to the cargo encompassed into autophagosome and delivery of cargo to lysosomes to degrade and to release macromolecules back into the cytosol. [10] If the "self-digestion" gets out of control, the autophagy dysfunction, including excessive autophagy induction or suppression of autophagy flux, will induce serious diseases, such as cancer, neurodegenerative diseases, immunological diseases, innate turbulence, and even cell death. [11] Therefore, autophagy is Nanomaterials (NMs) are comprehensively applied in biomedicine due to their unique physical and chemical properties. Autophagy, as an evolutionarily conserved cellular quality control process, is closely associated with the effect of NMs on cells. In this review, the recent advances in NM-induced/ inhibited autophagy (NM-phagy) are summarized, with an aim to present a comprehensive description of the mechanisms of NM-phagy from the perspective of internalization, activation, and termination, thereby bridging autophagy and nanomaterials. Several possible mechanisms are extensively ...

Few Layer Graphene Does Not Affect Cellular Homeostasis of Mouse Macrophages

“…To further explore the activation profile of the macrophages following their incubation with different concentrations of FLG (3,10,30, and 100 µg/mL) along with untreated and LPS-treated cells, we determined the titers of pro-inflammatory cytokines (IL-6, TNFα, and IL-1β) in the culture supernatants by ELISA. As shown in Figure 5, IL-6 secretion slightly increases with FLG concentration, though not significantly when compared to untreated cells.…”

“…Recently, the autophagic pathway has been considered as a key process involved in cell death and in survival mechanisms of immune cells exposed to nanomaterials. It has also been alluded to in accounting for the eventual fate of cell internalized nanomaterials [10]. Autophagy is a conserved intracellular process that delivers cytoplasmic contents to lysosomes for degradation based on the formation of double-membrane autophagosomes [10].…”

“…It has also been alluded to in accounting for the eventual fate of cell internalized nanomaterials [10]. Autophagy is a conserved intracellular process that delivers cytoplasmic contents to lysosomes for degradation based on the formation of double-membrane autophagosomes [10]. Cells tend to regulate autophagy, which is usually present at a basal level, but they also induce autophagy to break down parts of its own proteins or organelles to stay alive under pathophysiological conditions [11].…”

“…Cells tend to regulate autophagy, which is usually present at a basal level, but they also induce autophagy to break down parts of its own proteins or organelles to stay alive under pathophysiological conditions [11]. Autophagy is frequently activated in many immune cells, and nowadays it is widely studied to better understand the interaction of nanomaterials with mammalian cells, and even with respect to whole organs [10]. Within the class of GRMs, GO has been found to induce autophagy in cells such as macrophages and in the colon cancer cell line CT26, simultaneously activating toll-like receptors TLR 4 and TLR 9 [12,13].…”

Selective Autophagy Pathway of Nanoparticles and Nanodrugs: Drug Delivery and Pathophysiological Effects

“…[23,24] Researchers have reported the intracellular uptake of nanoparticles or nanodrugs through endocytosis mechanisms, but their intracellular processing through selective autophagy remains unclear. [25][26][27] More importantly, the induction or inhibition of autophagy by various nanoparticles or nanodrugs indicates its potential value in terms of safety and application in the treatment of various autophagy-related diseases [28][29][30][31][32][33] Previously, we reported for the first time that Ub-decorated nanoparticles bind to autophagy receptors and are then linked to LC3 for entry into the selective autophagy pathway, facilitating their delivery to lysosomes. [34] We termed this processing of nanoparticles and nanodrugs through selective autophagy pathways "nanoparticulophagy."…”