Designing a C84 fullerene as a specific voltage-gated sodium channel blocker

Insights into the toxicological effects of nanomaterials on atherosclerosis: mechanisms involved and influence factors

Atherosclerosis is one of the most common types of cardiovascular disease and is driven by lipid accumulation and chronic inflammation in the arteries, which leads to stenosis and thrombosis. Researchers have been working to design multifunctional nanomedicines with the ability to target, diagnose, and treat atherosclerosis, but recent studies have also identified that nanomaterials can cause atherosclerosis. Therefore, this review aims to outline the molecular mechanisms and physicochemical properties of nanomaterials that promote atherosclerosis. By analyzing the toxicological effects of nanomaterials on cells involved in the pathogenesis of atherosclerosis such as vascular endothelial cells, vascular smooth muscle cells and immune cells, we aim to provide new perspectives for the prevention and treatment of atherosclerosis, and raise awareness of nanotoxicology to advance the clinical translation and sustainable development of nanomaterials.

Understanding the interactions between inorganic-based nanomaterials and biological membranes

The interactions between inorganic-based nanomaterials (NMs) and biological membranes are among the most important phenomena for developing NM-based therapeutics and resolving nanotoxicology. Herein, we introduce the structural and functional effects of inorganic-based NMs on biological membranes, mainly the plasma membrane and the endomembrane system, with an emphasis on the interface, which involves highly complex networks between NMs and biomolecules (such as membrane proteins and lipids). Significant efforts have been devoted to categorizing and analyzing the interaction mechanisms in terms of the physicochemical characteristics and biological effects of NMs, which can directly or indirectly influence the effects of NMs on membranes. Importantly, we summarize that the biological membranes act as platforms and thereby mediate NMs-immune system contacts. In this overview, the existing challenges and potential applications in the areas are addressed. A strong understanding of the discussed concepts will promote therapeutic NM designs for drug delivery systems by leveraging the NMs-membrane interactions and their functions.

Interactions of nanomaterials with ion channels and related mechanisms

The pharmacological potential of nanotechnology, especially in drug delivery and bioengineering, has developed rapidly in recent decades. Ion channels, which are easily targeted by external agents, such as nanomaterials (NMs) and synthetic drugs, due to their unique structures, have attracted increasing attention in the fields of nanotechnology and pharmacology for the treatment of ion channel-related diseases. NMs have significant effects on ion channels, and these effects are manifested in many ways, including changes in ion currents, kinetic characteristics and channel distribution. Subsequently, intracellular ion homeostasis, signalling pathways, and intracellular ion stores are affected, leading to the initiation of a range of biological processes. However, the effect of the interactions of NMs with ion channels is an interesting topic that remains obscure. In this review, we have summarized the recent research progress on the direct and indirect interactions between NMs and ion channels and discussed the related molecular mechanisms, which are crucial to the further development of ion channel-related nanotechnological applications.

C60 fullerenes selectively inhibit BKCa but not Kv channels in pulmonary artery smooth muscle cells

Possessing unique physical and chemical properties, C₆₀ fullerenes are arising as a potential nanotechnological tool that can strongly affect various biological processes. Recent molecular modeling studies have shown that C₆₀ fullerenes can interact with ion channels, but there is lack of data about possible effects of C₆₀ molecule on ion channels expressed in smooth muscle cells (SMC). Here we show both computationally and experimentally that water-soluble pristine C₆₀ fullerene strongly inhibits the large conductance Ca²⁺-dependent K⁺ (BK_Ca), but not voltage-gated K⁺ (K_v) channels in pulmonary artery SMC. Both molecular docking simulations and analysis of single channel activity indicate that C₆₀ fullerene blocks BK_Ca channel pore in its open state. In functional tests, C₆₀ fullerene enhanced phenylephrine-induced contraction of pulmonary artery rings by about 25% and reduced endothelium-dependent acetylcholine-induced relaxation by up to 40%. These findings suggest a novel strategy for biomedical application of water-soluble pristine C₆₀ fullerene in vascular dysfunction.

Fullerenol C60(OH)36 at relatively high concentrations impairs hippocampal theta oscillations (in vivo and in vitro) and triggers epilepsy (in vitro) - A dose response study

Since the first identification of fullerenes (C₆₀) and their synthesis in 1985, those compounds have been extensively studied in the biomedical field. In particular, their water-soluble derivatives, fullerenols (C₆₀(OH)_n, n = 2-48), have recently been the subject of numerous investigations concerning their antioxidant and prooxidant properties in biological systems. A small fraction of that research has focused on the possible use of C₆₀ and C₆₀(OH)_n in neuroscience and the therapy of pathologies such as dementia, amyloid-β (Aβ) formation, and Parkinson's disease. However, only a few studies have focused on their direct effects on neuronal network viability and excitability, especially with the use of electrophysiological and electrochemical approaches. Therefore, we addressed the issue of the direct effect of hydroxylated fullerene nanoparticles C₆₀(OH)₃₆ on local field potentials at the hippocampal formation (HPC) level. With the use of in vitro hippocampal formation slices as a stable model of inducing theta oscillations, and an in vivo model of an anesthetized rat, herein we provide the first convergent electropharmacological evidence that C₆₀(OH)₃₆ at relatively high concentrations (60 μM and 80 μM in vitro; 0.2 μg/μl in vivo) is capable of attenuating the amplitude, power, and frequency of theta oscillations in the HPC neuronal network. At the same time, lower concentrations did not induce any apparent changes. Theta band oscillations constitute a key physiological phenotypic property, which served here as a sensitive assay enabling the study of neural network excitability. Moreover, we report that C₆₀(OH)₃₆ at the concentrations of 60 μM and 80 μM is capable of producing epilepsy in the HPC in vitro, which suggests that C₆₀(OH)_n, when applied at higher doses, may have a deleterious effect on the functioning of neuronal networks.

C60 fullerenes disrupt cellular signalling leading to TRPC4 and TRPC6 channels opening by the activation of muscarinic receptors and G-proteins in small intestinal smooth muscles

The effect of water-soluble pristine C₆₀ fullerene nanoparticles (C₆₀NPs) on receptor-operated cation channels formed by TRPC4/C6 proteins in ileal smooth muscle cells was investigated for the first time. Activation of these channels subsequent to acetylcholine binding to the expressed in these cells M₂ and M₃ muscarinic receptors represents the key event in the parasympathetic control of gastrointestinal smooth muscle motility and cholinergic excitation-contraction coupling. Experiments were performed on single collagenase-dispersed mouse ileal myocytes using patch-clamp techniques with symmetrical 125mM Cs⁺ solutions and [Ca²⁺]_i 'clamped' at 100nM in order to isolate the muscarinic cation current (mI_CAT). The current was induced by intracellular infusion of 200μM GTPγS, which activates G-proteins directly, i.e. bypassing the muscarinic receptors. C₆₀NPs applied at 10^-6M at peak response to activation of G-proteins caused mI_CAT inhibition by 47.0±3.5% (n=9). The inhibition developed rather slowly, with the time constant of 119±16s, was voltage-independent and irreversible. Thus, C₆₀NPs are unlikely to cause any direct block of TRPC4/C6 channels; rather, they may accumulate in the membrane and disrupt G-protein signalling leading to mI_CAT generation. C₆₀NPs may represent a novel class of biocompatible molecules for the treatment of disorders associated with enhanced gastrointestinal motility.

Functionalized Fullerene Targeting Human Voltage-Gated Sodium Channel, hNav1.7

Mutations of hNa_v1.7 that cause its activities to be enhanced contribute to severe neuropathic pain. Only a small number of hNa_v1.7 specific inhibitors have been identified, most of which interact with the voltage-sensing domain of the voltage-activated sodium ion channel. In our previous computational study, we demonstrated that a [Lys₆]-C₈₄ fullerene binds tightly (affinity of 46 nM) to Na_vAb, the voltage-gated sodium channel from the bacterium Arcobacter butzleri. Here, we extend this work and, using molecular dynamics simulations, demonstrate that the same [Lys₆]-C₈₄ fullerene binds strongly (2.7 nM) to the pore of a modeled human sodium ion channel hNa_v1.7. In contrast, the fullerene binds only weakly to a mutated model of hNa_v1.7 (I1399D) (14.5 mM) and a model of the skeletal muscle hNa_v1.4 (3.7 mM). Comparison of one representative sequence from each of the nine human sodium channel isoforms shows that only hNa_v1.7 possesses residues that are critical for binding the fullerene derivative and blocking the channel pore.

SuperPain--a resource on pain-relieving compounds targeting ion channels

Pain is more than an unpleasant sensory experience associated with actual or potential tissue damage: it is the most common reason for physician consultation and often dramatically affects quality of life. The management of pain is often difficult and new targets are required for more effective and specific treatment. SuperPain (http://bioinformatics.charite.de/superpain/) is freely available database for pain-stimulating and pain-relieving compounds, which bind or potentially bind to ion channels that are involved in the transmission of pain signals to the central nervous system, such as TRPV1, TRPM8, TRPA1, TREK1, TRESK, hERG, ASIC, P2X and voltage-gated sodium channels. The database consists of ∼8700 ligands, which are characterized by experimentally measured binding affinities. Additionally, 100 000 putative ligands are included. Moreover, the database provides 3D structures of receptors and predicted ligand-binding poses. These binding poses and a structural classification scheme provide hints for the design of new analgesic compounds. A user-friendly graphical interface allows similarity searching, visualization of ligands docked into the receptor, etc.