GV-971 attenuates α-Synuclein aggregation and related pathology.

RATIONALE: Synucleinopathies, including Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), share a distinct pathological feature, that is, a widespread accumulation of α-synuclein (α-syn) in the brain. There is a significant clinical unmet need for disease-modifying treatments for synucleinopathies. Recently, a seaweed-derived mixture of oligosaccharides sodium oligomannate, GV-971, was approved for Phase 2 clinical trials for PD. This study aimed to further evaluate the therapeutic effects of GV-971 on synucleinopathies using cellular and animal models and explore its associated molecular mechanisms. METHODS: α-Syn aggregation was assessed, in vitro and ex vivo, by ThT assay. A dopaminergic neuron cell line, Prnp-SNCAA53T mice, and brain slices from PD and DLB patients were used to determine the efficacy of GV-971 in ameliorating α-syn pathology. Measurements of motor functions, including pole, cylinder, and rotarod tests, were conducted on Prnp-SNCAA53T mice 4 weeks after intragastric administration of GV-971 (200 mg day-1 kg-1 ). RESULTS: GV-971 effectively prevented α-syn aggregation and even disassembled pre-aggregated α-syn fibrils, in vitro and ex vivo. In addition, GV-971 was able to rescue α-syn-induced neuronal damage and reduced release of extracellular vesicles (EVs), likely via modulating Alix expression. In the Prnp-SNCAA53T mouse model, when treated at the age of 5 months, GV-971 significantly decreased α-syn deposition in the cortex, midbrain, and cerebellum regions, along with ameliorating the motor dysfunctions. CONCLUSIONS: Our results indicate that GV-971, when administered at a relatively early stage of the disease process, significantly reduced α-syn accumulation and aggregation in Prnp-SNCAA53T mice. Furthermore, GV-971 corrected α-syn-induced inhibition of EVs release in neurons, contributing to neuronal protection. Future studies are needed to further assess GV-971 as a promising disease-modifying therapy for PD and other synucleinopathies.

Triptolide nanoemulsion gel as a transdermal drug delivery system: preparation, pharmacokinetics, and rheumatoid arthritis evaluation.

PURPOSE: This study aimed to develop and evaluate triptolide nanoemulsion gels (TP-NE gels) as a transdermal drug delivery system. METHODS: TP-NE was prepared and optimized via emulsification and the central composite design response surface method. The optimized TP-NE gel was evaluated in vitro and in vivo. TP-NE gel microstructure, in vitro and in vivo pharmacokinetics, and anti-rheumatoid arthritis effects were studied to evaluate the feasibility of its percutaneous administration. RESULTS: The Optimized TP-NE was observed using a Malvern Autosizer Nano ZS 90 inspection system and a transmission electron microscope (TEM). The nanoemulsion had an average size of 162.9 ± 0.281 nm, a polydispersity index of 0.272 ± 0.024, a zeta potential of -30.03 ± 2.01 mV, and mostly spherical and uniform morphology. In addition, the TP-NE gel pharmacokinetics, assessed via a skin-blood two-site synchronous microdialysis, revealed that TP was higher in the skin than in the blood. TP-NE gel is crucial in reducing knee edema, inhibiting inflammation, and treating rheumatoid arthritis by regulating tumor necrosis factor-alpha, interleukin-1ß, and -6 levels. CONCLUSION: The TP-NE gel is a promising local delivery method for rheumatoid arthritis (RA)-associated edema and inflammation and can serve as a prospective platform for percutaneous TP administration.

Erythrocytic α-synuclein contained in microvesicles regulates astrocytic glutamate homeostasis: a new perspective on Parkinson's disease pathogenesis.

Parkinson's disease is a neurodegenerative disorder characterized by the transmission and accumulation of toxic species of α-synuclein (α-syn). Extracellular vesicles (EVs) are believed to play a vital role in the spread of toxic α-syn species. Recently, peripheral α-syn pathology has been investigated, but little attention has been devoted to erythrocytes, which contain abundant α-syn. In this study, we first demonstrated that erythrocyte-derived EVs isolated from Parkinson's disease patients carried elevated levels of oligomeric α-syn, compared to those from healthy controls. Moreover, human erythrocyte-derived EVs, when injected into peripheral blood in a mouse model of Parkinson's disease, were found to readily cross the blood-brain barrier (BBB). These EVs accumulated in astrocyte endfeet, a component of the BBB, where they impaired glutamate uptake, likely via interaction between excitatory amino acid transporter 2 (EAAT2) and oligomeric α-syn. These data suggest that erythrocyte-derived EVs and the oligomeric α-syn carried in them may play critical roles in the progression or even initiation of Parkinson's disease. Additionally, the mechanisms involved are attributable at least in part to dysfunction of astrocytes induced by these EVs. These observations provide new insight into the understanding of the mechanisms involved in Parkinson's disease.

Reduced oligodendrocyte exosome secretion in multiple system atrophy involves SNARE dysfunction.

Transportation of key proteins via extracellular vesicles has been recently implicated in various neurodegenerative disorders, including Parkinson's disease, as a new mechanism of disease spreading and a new source of biomarkers. Extracellular vesicles likely to be derived from the brain can be isolated from peripheral blood and have been reported to contain higher levels of α-synuclein (α-syn) in Parkinson's disease patients. However, very little is known about extracellular vesicles in multiple system atrophy, a disease that, like Parkinson's disease, involves pathological α-syn aggregation, though the process is centred around oligodendrocytes in multiple system atrophy. In this study, a novel immunocapture technology was developed to isolate blood CNPase-positive, oligodendrocyte-derived enriched microvesicles (OEMVs), followed by fluorescent nanoparticle tracking analysis and assessment of α-syn levels contained within the OEMVs. The results demonstrated that the concentrations of OEMVs were significantly lower in multiple system atrophy patients, compared to Parkinson's disease patients and healthy control subjects. It is also noted that the population of OEMVs involved was mainly in the size range closer to that of exosomes, and that the average α-syn concentrations (per vesicle) contained in these OEMVs were not significantly different among the three groups. The phenomenon of reduced OEMVs was again observed in a transgenic mouse model of multiple system atrophy and in primary oligodendrocyte cultures, and the mechanism involved was likely related, at least in part, to an α-syn-mediated interference in the interaction between syntaxin 4 and VAMP2, leading to the dysfunction of the SNARE complex. These results suggest that reduced OEMVs could be an important mechanism related to pathological α-syn aggregation in oligodendrocytes, and the OEMVs found in peripheral blood could be further explored for their potential as multiple system atrophy biomarkers.

Transdermal drug delivery of triptolide-loaded nanostructured lipid carriers: Preparation, pharmacokinetic, and evaluation for rheumatoid arthritis.

The objective of this present study was to develop and evaluate the triptolide-loaded nanostructured lipid carriers (TPL-NLCs) for transdermal drug delivery system (TDDS). TPL-NLCs was prepared with emulsification technique and optimized by central composite design of a response surface methodology (CCD-RSM). The optimized TPL-NLCs were spherical and physically stable with the average size of 139.6.0 ±â€¯2.53 nm and Zeta potential of -36.03 ±â€¯2.41 mV. The encapsulation efficiency and drug loading were 97.15% ±â€¯9.46 and 10.35% ±â€¯1.12, respectively. Moreover, the in vitro release study showed that TPL-NLCs had a sustained release profiles and the in vitro penetration study indicated that TPL-NLCs could effectively penetrate into skin. Besides, the methodology of skin-blood synchronous microdialysis was established to evaluate the pharmacokinetics of TPL-NLCs in vivo and the results displayed that the TPL concentration in skin was higher than that in blood. And TPL-NLCs presented a remarkable effect of decreasing knee edema, inhibiting inflammation by regulating the levels of TNF-α, IL-1ß and IL-6, which indicated that TPL-NLCs was a promising topical administration in treatment of edema and inflammation associated with rheumatoid arthritis (RA).

Lipid nanoparticles loading triptolide for transdermal delivery: mechanisms of penetration enhancement and transport properties.

BACKGROUND: In recent years, nanoparticles (NPs) including nanostructured lipid carries (NLC) and solid lipid nanoparticles (SLN) captured an increasing amount of attention in the field of transdermal drug delivery system. However, the mechanisms of penetration enhancement and transdermal transport properties of NPs are not fully understood. Therefore, this work applied different platforms to evaluate the interactions between skin and NPs loading triptolide (TPL, TPL-NLC and TPL-SLN). Besides, NPs labeled with fluorescence probe were tracked after administration to investigate the dynamic penetration process in skin and skin cells. In addition, ELISA assay was applied to verify the in vitro anti-inflammatory effect of TPL-NPs. RESULTS: Compared with the control group, TPL-NPs could disorder skin structure, increase keratin enthalpy and reduce the SC infrared absorption peak area. Besides, the work found that NPs labeled with fluorescence probe accumulated in hair follicles and distributed throughout the skin after 1 h of administration and were taken into HaCaT cells cytoplasm by transcytosis. Additionally, TPL-NLC could effectively inhibit the expression of IL-4, IL-6, IL-8, IFN-γ, and MCP-1 in HaCaT cells, while TPL-SLN and TPL solution can only inhibit the expression of IL-6. CONCLUSIONS: TPL-NLC and TPL-SLN could penetrate into skin in a time-dependent manner and the penetration is done by changing the structure, thermodynamic properties and components of the SC. Furthermore, the significant anti-inflammatory effect of TPL-NPs indicated that nanoparticles containing NLC and SLN could serve as safe prospective agents for transdermal drug delivery system.

Development of triptolide-nanoemulsion gels for percutaneous administration: physicochemical, transport, pharmacokinetic and pharmacodynamic characteristics.

BACKGROUND: This work aimed to provide useful information on the use of nanoemulsions for the percutaneous administration of triptolide. Lipid nanosystems have great potential for transdermal drug delivery. Nanoemulsions and nanoemulsion gels were prepared to enhance percutaneous permeation. Microstructure and in vitro/in vivo percutaneous delivery characteristics of triptolide (TPL)-nanoemulsions and TPL-nanoemulsion gels were compared. The integrity of the nanoemulsions and nanoemulsion gels during transdermal delivery and its effects on the surface of skin were also investigated. The penetration mechanisms of nanoemulsions and nanoemulsion gels were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The transport characteristics of fluorescence-labelled nanoemulsions were probed using laser scanning confocal microscopy. A chronic dermatitis/eczema model in mice ears and the pharmacodynamic of the TPL-nanoemulsion gels were also investigated. RESULTS: Compared to TPL gels, significantly greater cumulative amounts of TPL-nanoemulsion gels and TPL-nanoemulsions penetrated rat skin in vitro. The in vivo microdialysis showed the concentration-time curve AUC0-t for TPL-NPs is bigger than the TPL-gels. At the same time, TPL-NPs had a larger effect on the surface of skin. By hydrating keratin and changing the structure of both the stratum corneum lipids and keratin, nanoemulsions and nanoemulsion gels influence skin to promote percutaneous drug penetration. Both hairfollicles and the stratum corneum are also important in this transdermal drug delivery system. Moderate and high dosages of the TPL-nanoemulsion gels can significantly improve the symptoms of dermatitis/eczema inflammation and edema erythematic in mice ears and can reduce the expression of IFN-γ and IL-4. Moreover, the TPL-nanoemulsion gels cause less gastrointestinal damage than that of the Tripterygium wilfordii oral tablet does. CONCLUSIONS: Nanoemulsions could be suitable for transdermal stably releasing drugs and maintaining the effective drug concentration. The TPL-nanoemulsion gels provided higher percutaneous amounts than other carriers did. These findings suggest that nanoemulsion gels could be promising percutaneous carriers for TPL. The TPL-nanoemulsion gels have a significant treatment effect on dermatitis/eczema in the mice model and is expected to provide a new, low-toxicity and long-term preparation for the clinical treatment of dermatitis/eczema in transdermal drug delivery systems.

[Development of Tripterygium glycosides nano-carries based on "nanoemulsion-gels" and its pharmacodynamics].

The aim of this study is to develop the Tripterygium glycosides nanoemulsion gels and investigate its pharmacodynamics. Oleic acid was used as oil phase, polyoxyethylene castor oil as surfaetant, and 1,2-propanediol as cosurfactant to screen the formula of Tripterygium glycoside nanoemulsion using the pseudo-temary phase diagrams. Then the nanoemulsion gels was prepared. The ICR mouse ears were sensitazated by 7% DNCB, and then were excited by 0.3% DNCB to stimulate the model of mouse chronic dermatitis and eczema. The concentrations of IFN-γ, IL-4 and IL-8 in mouse blood were determined by ELISA. The results showed that Tripterygium glycosides nanoemulsion gels could significantly inhibit the swelling of mouse ears(P < 0.01) and ameliorate the edama and erythema of model mouse ears skin. Also it could significantly decrease the expression of IFN-γ and IL-4 in model mouse blood. Tripterygium glycosides nanoemulsion gels had a good therapeutic effect on mouse model of dermatitis and eczema. It was expected to provide a new and long-acting exterernal preparation for the treatment of dermatitis and eczema.