scholarly journals A Novel Treatment Strategy by Natural Products in NLRP3 Inflammasome-Mediated Neuroinflammation in Alzheimer’s and Parkinson’s Disease

2021 ◽  
Vol 22 (3) ◽  
pp. 1324
Author(s):  
Jun Ho Lee ◽  
Hong Jun Kim ◽  
Jong Uk Kim ◽  
Tae Han Yook ◽  
Kyeong Han Kim ◽  
...  

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the most common neurodegenerative diseases. Many studies have demonstrated that the release of NLRP3 inflammasome-mediated proinflammatory cytokines by the excessive activation of microglia is associated with the pathogenesis of AD and PD and suggested that the NLRP3 inflammasome plays an important role in AD and PD development. In both diseases, various stimuli, such as Aβ and α-synuclein, accelerate the formation of the NLRP3 inflammasome in microglia and induce pyroptosis through the expression of interleukin (IL)-1β, caspase-1, etc., where neuroinflammation contributes to gradual progression and deterioration. However, despite intensive research, the exact function and regulation of the NLRP3 inflammasome has not yet been clearly identified. Moreover, there have not yet been any experiments of clinical use, although many studies have recently been conducted to improve treatment of inflammatory diseases using various inhibitors for NLRP3 inflammasome pathways. However, recent studies have reported that various natural products show improvement effects in the in vivo models of AD and PD through the regulation of NLRP3 inflammasome assembly. Therefore, the present review provides an overview of natural extraction studies aimed at the prevention or treatment of NLRP3 inflammasome-mediated neurological disorders. It is suggested that the discovery and development of these various natural products could be a potential strategy for NLRP3 inflammasome-mediated AD and PD treatment.


2021 ◽  
Author(s):  
Sahabuddin Ahmed ◽  
Samir Ranjan Panda ◽  
Mohit Kwatra ◽  
Bidya Dhar Sahu ◽  
VGM Naidu

Abstract Several activators of NLRP3 inflammasome have been described; however, the central mechanisms of NLRP3 inflammasome activation in brain microglia, especially at the activating step through free radical generation, still require further clarification. Hence the present study aimed to investigate the role of free radicals in activating NLRP3 inflammasome driven neurodegeneration and elucidated the neuroprotective role of perillyl alcohol (PA) in vitro and in vivo models of Parkinson’s disease. Initial priming of microglial cells with lipopolysaccharide (LPS) following treatment with hydrogen peroxide (H2O2) induces NF-κB translocation to nucleus with robust generation of free radicals that act as Signal 2 in augmenting NLRP3 inflammasome assembly and its downstream targets. PA treatment suppresses nuclear translocation of NF-κB and maintains cellular redox homeostasis in microglia that limits NLRP3 inflammasome activation along with processing active caspase-1, IL-1β and IL-18. To further correlates the in vitro study with in vivo MPTP model, treatment with PA also inhibits the nuclear translocation of NF-κB and downregulates the NLRP3 inflammasome activation. PA administration upregulates various antioxidant enzymes levels and restored the level of dopamine and other neurotransmitters in the striatum of the mice brain with improved behavioural activities. Additionally, treatment with Mito-TEMPO (a mitochondrial ROS inhibitor) was also seen to inhibit NLRP3 inflammasome and rescue dopaminergic neuron loss in the mice brain. Therefore, we conclude that NLRP3 inflammasome activation requires a signal from damaged mitochondria for its activation. Further pharmacological scavenging of free radicals restricts microglia activation and simultaneously supports neuronal survival via targeting NLRP3 inflammasome pathway in Parkinson’s disease.



Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 740 ◽  
Author(s):  
Chien-Tai Hong ◽  
Kai-Yun Chen ◽  
Weu Wang ◽  
Jing-Yuan Chiu ◽  
Dean Wu ◽  
...  

Background: Insulin resistance (IR), considered a hallmark of diabetes at the cellular level, is implicated in pre-diabetes, results in type 2 diabetes, and negatively affects mitochondrial function. Diabetes is increasingly associated with enhanced risk of developing Parkinson’s disease (PD); however, the underlying mechanism remains unclear. This study investigated the probable culpability of IR in the pathogenesis of PD. Methods: Using MitoPark mice in vivo models, diabetes was induced by a high-fat diet in the in vivo models, and IR was induced by protracted pulse-stimulation with 100 nM insulin treatment of neuronal cells, in vitro to determine the molecular mechanism(s) underlying altered cellular functions in PD, including mitochondrial dysfunction and α-synuclein (SNCA) aberrant expression. Findings: We observed increased SNCA expression in the dopaminergic (DA) neurons of both the wild-type and diabetic MitoPark mice, coupled with enhanced degeneration of DA neurons in the diabetic MitoPark mice. Ex vivo, in differentiated human DA neurons, IR was associated with increased SNCA and reactive oxygen species (ROS) levels, as well as mitochondrial depolarization. Moreover, we demonstrated concomitant hyperactivation of polo-like kinase-2 (PLK2), and upregulated p-SNCA (Ser129) and proteinase K-resistant SNCA proteins level in IR SH-SY5Y cells, however the inhibition of PLK2 reversed IR-related increases in phosphorylated and total SNCA. Similarly, the overexpression of peroxisome proliferator-activated receptor-γ coactivator 1-alpha (PGC)-1α suppressed ROS production, repressed PLK2 hyperactivity, and resulted in downregulation of total and Ser129-phosphorylated SNCA in the IR SH-SY5Y cells. Conclusions: These findings demonstrate that IR-associated diabetes promotes the development and progression of PD through PLK2-mediated mitochondrial dysfunction, upregulated ROS production, and enhanced SNCA signaling, suggesting the therapeutic targetability of PLK2 and/or SNCA as potential novel disease-modifying strategies in patients with PD.



2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jialong Chen ◽  
Kanmin Mao ◽  
Honglin Yu ◽  
Yue Wen ◽  
Hua She ◽  
...  

Abstract Background Parkinson’s disease (PD) is characterized by degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc), accompanied by accumulation of α-synuclein, chronic neuroinflammation and autophagy dysfunction. Previous studies suggested that misfolded α-synuclein induces the inflammatory response and autophagy dysfunction in microglial cells. The NLRP3 inflammasome signaling pathway plays a crucial role in the neuroinflammatory process in the central nervous system. However, the relationship between autophagy deficiency and NLRP3 activation induced by α-synuclein accumulation is not well understood. Methods Through immunoblotting, immunocytochemistry, immunofluorescence, flow cytometry, ELISA and behavioral tests, we investigated the role of p38-TFEB-NLRP3 signaling pathways on neuroinflammation in the α-synuclein A53T PD models. Results Our results showed that increased protein levels of NLRP3, ASC, and caspase-1 in the α-synuclein A53T PD models. P38 is activated by overexpression of α-synuclein A53T mutant, which inhibited the master transcriptional activator of autophagy TFEB. And we found that NLRP3 was degraded by chaperone-mediated autophagy (CMA) in microglial cells. Furthermore, p38-TFEB pathways inhibited CMA-mediated NLRP3 degradation in Parkinson's disease. Inhibition of p38 had a protective effect on Parkinson's disease model via suppressing the activation of NLRP3 inflammasome pathway. Moreover, both p38 inhibitor SB203580 and NLRP3 inhibitor MCC950 not only prevented neurodegeneration in vivo, but also alleviated movement impairment in α-synuclein A53T-tg mice model of Parkinson’s disease. Conclusion Our research reveals p38-TFEB pathways promote microglia activation through inhibiting CMA-mediated NLRP3 degradation in Parkinson's disease, which could be a potential therapeutic strategy for PD. Graphical abstract p38-TFEB pathways promote microglia activation through inhibiting CMA-mediated NLRP3 degradation in Parkinson's disease. In this model, p38 activates NLRP3 inflammasome via inhibiting TFEB in microglia. TFEB signaling negatively regulates NLRP3 inflammasome through increasing LAMP2A expression, which binds to NLRP3 and promotes its degradation via chaperone-mediated autophagy (CMA). NLRP3-mediated microglial activation promotes the death of dopaminergic neurons.



Neuroscience ◽  
2014 ◽  
Vol 258 ◽  
pp. 385-400 ◽  
Author(s):  
X. Yue ◽  
D.J. Hariri ◽  
B. Caballero ◽  
S. Zhang ◽  
M.J. Bartlett ◽  
...  


2019 ◽  
Vol 19 (3-4) ◽  
pp. 101-108
Author(s):  
Di Nan ◽  
Yingying Cheng ◽  
Liangshu Feng ◽  
Mingming Zhao ◽  
Di Ma ◽  
...  

Background: Leukoaraiosis (LA), widely accepted as a feature of cerebral small vessel disease, significantly increases the incidence of stroke, dementia, and death. Cerebral small artery disease has been considered as one of the main causes of LA. However, since the term “venous collagenosis” (VC) was proposed in an atrophy research in 1995, there have been pathological and neuroimaging studies proving the association between the venous system and LA in aging, Alz­heimer’s disease (AD), and Parkinson’s disease. Summary: Autopsy studies confirmed that thickening of the lumen wall in venules, which results from the deposition of collagen I and III, leading to vessel stenosis or occlusion, is closely associated with LA. Susceptibility-weighted imaging research revealed a controversial association of deep medullary veins and LA in vivo, regarding which there are no standard criteria currently. Nevertheless, retinal venous changes had been reported to increase the risk of LA development, providing a novel way for in vivo evaluation. As for the internal jugular vein, jugular venous reflux could double the LA score in aging and modulate circulation of cerebral spinal fluids. Key Messages: Disruption of the venous system was notably associated with LA in aging, AD, and Parkinson’s disease post-mortem and in in vivo models. The venous pathological changes may induce cerebral hypoperfusion, drainage system disruption, and vasogenic oedema in the veins around the periventricular white matter. The clarification of VC in LA may provide an early prevention and early treatment strategy for LA patients.





2008 ◽  
Vol 1214 ◽  
pp. 169-176 ◽  
Author(s):  
A. Oyagi ◽  
Y. Oida ◽  
H. Hara ◽  
H. Izuta ◽  
M. Shimazawa ◽  
...  


2021 ◽  
Author(s):  
Anna Masato ◽  
Nicoletta Plotegher ◽  
Andrea Thor ◽  
Stephen Adams ◽  
Michele Sandre ◽  
...  

Dopamine dyshomeostasis has been acknowledged to be among the determinants of nigrostriatal neuron degeneration in Parkinson's disease (PD). Several studies in experimental models and postmortem PD patients underlined increasing levels of the aldehydic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is highly reactive towards proteins. DOPAL has been shown to covalently modify the presynaptic protein αSynuclein (αSyn), whose misfolding and aggregation represent a major trait of PD pathology, triggering αSyn oligomerization in dopaminergic neurons. Here, we demonstrated that DOPAL elicits αSyn neuronal accumulation and hampers αSyn clearance at synapses and the soma. By combining cellular and in vivo models, we provided evidence that DOPAL-induced αSyn buildup lessens neuronal resilience, compromises synaptic integrity, and overwhelms protein quality control pathways, specifically at neuronal projections. The resulting progressive decline of neuronal homeostasis leads to dopaminergic neuron loss and motor impairment, corroborating the αSyn-DOPAL interplay as an early event in PD neurodegeneration.



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