Inhibitory effect of mitoquinone against the α-synuclein fibrillation and relevant neurotoxicity: possible role in inhibition of Parkinson's disease

The mechanistic interaction, aggregation and neurotoxicity of α-synuclein after interaction with glycyrrhizic acid: Modulation of synucleinopathies

This article reveals the binding mechanism between glycyrrhizic acid (GA) and α-synuclein to may provide further information for the modulation of synucleinopathies using bioactive compounds. Therefore, the inhibitory activities of GA against α-synuclein aggregation and induced neurotoxicity were evaluated using different assays. Results showed that α-synuclein-GA binding was mediated by intermolecular hydrogen bonds leading to the formation of a slightly folded complex. Theoretical studies revealed that GA binds to the N-terminal domain of α-synuclein and triggers a compact structure around a major part of the N-terminal and the NAC regions along with fluctuations in the C-terminal domain, which are prerequisites for the inhibition of α-synuclein aggregation. Then, the cellular assays showed that GA as a potential small molecule can inhibit the oligomerization of α-synuclein and relevant neurotoxicity through modulation of neural viability, membrane leakage, and ROS formation in a concentration-dependent manner. As a result, the primary mechanism of GA's anti-aggregation and neuroprotective activities is the reorganized α-synuclein structure and fluctuating C-terminal domain, which promotes long-range transient intramolecular contacts between the N-terminal and the C-terminal domain.

Mitochondria-Targeted Antioxidants, an Innovative Class of Antioxidant Compounds for Neurodegenerative Diseases: Perspectives and Limitations

Neurodegenerative diseases comprise a wide spectrum of pathologies characterized by progressive loss of neuronal functions and structures. Despite having different genetic backgrounds and etiology, in recent years, many studies have highlighted a point of convergence in the mechanisms leading to neurodegeneration: mitochondrial dysfunction and oxidative stress have been observed in different pathologies, and their detrimental effects on neurons contribute to the exacerbation of the pathological phenotype at various degrees. In this context, increasing relevance has been acquired by antioxidant therapies, with the purpose of restoring mitochondrial functions in order to revert the neuronal damage. However, conventional antioxidants were not able to specifically accumulate in diseased mitochondria, often eliciting harmful effects on the whole body. In the last decades, novel, precise, mitochondria-targeted antioxidant (MTA) compounds have been developed and studied, both in vitro and in vivo, to address the need to counter the oxidative stress in mitochondria and restore the energy supply and membrane potentials in neurons. In this review, we focus on the activity and therapeutic perspectives of MitoQ, SkQ1, MitoVitE and MitoTEMPO, the most studied compounds belonging to the class of MTA conjugated to lipophilic cations, in order to reach the mitochondrial compartment.

lncRNA NEAT1 promotes autophagy of neurons in mice by impairing miR-107-5p

This work focused on the exploration of NEAT1 in Parkinson’s disease (PD) and aimed to explore its effects on PD and related molecular mechanisms. Two experimental models were initially constructed, including MPTP-induced mice in vivo and the MPP+-induced SH-SY5Y cell line in vitro. Immunofluorescence assays were conducted to determine the TH+ positive cell rate. Pole tests and rotarod tests were also performed for the visualization of behavioral changes in mice. Cellular apoptosis was determined using MTT and flow cytometry assays. Changes in the number of autophagosomes were obtained under a transmission electron microscope. The content of dopamine was confirmed by high performance liquid chromatography. The targeted interrelationship between miR-107-5p and NEAT1 was clarified via dual-luciferase reporter gene assays. Meanwhile, mRNA and protein expressions were also detected using qRT-PCR and Western blot respectively. Furthermore, the level of NEAT1 was positively correlated with MPP+ concentration. Interfering with NEAT1 in the present study promoted cellular proliferation and mediated SH-SY5Y cell apoptosis and autophagy treated with MPP+. An increase was discovered in TH positive neurons and suppressive autophagy in PD mice. miR-107-5p was then considered as a NEAT1 putative target involving apoptosis and autophagy of SH-SY5Y cells. Interfering with NEAT1 efficiently facilitated the viability of SH-SY5Y cells and drastically suppressed autophagy and apoptosis of PD mice induced by MPTP- via elevating miR-107-5p level, which indicated that lncRNA NEAT1 acted as a latent therapeutic factor for PD treatment.