Inflammation as a causative factor in the aetiology of Parkinson's disease

The angiotensin (1-7) glycopeptide PNA5 improves cognition in a chronic progressive mouse model of Parkinson's disease through modulation of neuroinflammation

Cognitive decline in Parkinson's Disease (PD) is a prevalent and undertreated aspect of disease. Currently, no therapeutics adequately improve this aspect of disease. It has been previously shown that MAS receptor agonism via the glycosylated Angiotensin (1-7) peptide, PNA5, effectively reduces cognitive decline in models of vascular contributions to cognitive impairment and dementia (VCID). PNA5 has a brain/plasma ratio of 0.255 indicating good brain penetration. The goal of the present study was to determine if (1) systemic administration of PNA5 rescued cognitive decline in a mouse model of PD, and (2) if improvements in cognitive status could be correlated with changes to histopathological or blood plasma-based changes. Mice over-expressing human, wild-type α-synuclein (αSyn) under the Thy1 promoter (Thy1-αSyn mice, "line 61") were used as a model of PD with cognitive decline. Thy1-αSyn mice were treated with a systemic dose of PNA5, or saline (1 mg/kg/day) beginning at 4 months of age and underwent behavioral testing at 6 months, compared to WT. Subsequently, mice brains were analyzed for changes to brain pathology, and blood plasma was examined with a Multiplex Immunoassay for peripheral cytokine changes. Treatment with PNA5 reversed cognitive dysfunction measured by Novel Object Recognition and spontaneous alteration in a Y-maze in Thy1-αSyn mice. PNA5 treatment was specific to cognitive deficits, as fine-motor disturbances were unchanged. Enhanced cognition was associated with decreases in hippocampal inflammation and reductions in circulating levels of Macrophage Induced Protein (MIP-1β). Additionally, neuronal loss was blunted within the CA3 hippocampal region of PNA5-treated αsyn mice. These data reveal that PNA5 treatment reduces cognitive dysfunction in a mouse model of PD. These changes are associated with decreased MIP-1β levels in plasma identifying a candidate biomarker for target engagement. Thus, PNA5 treatment could potentially fill the therapeutic gap for cognitive decline in PD.

Inhibition of NLRP3 inflammasome ameliorates LPS-induced neuroinflammatory injury in mice via PINK1/Parkin pathway

Parkinson's disease (PD) is characterized by the severe loss of dopaminergic neurons in the substantia nigra pars compacta, leading to motor dysfunction. The onset of PD is often accompanied by neuroinflammation and α-Synuclein aggregation, and extensive research has focused on the activation of microglial NLRP3 inflammasomes in PD, which promotes the death of dopaminergic neurons. In this study, a model of cerebral inflammatory response was constructed in wild-type and Parkin＋/－ mice through bilateral intraventricular injection of LPS. LPS-induced activation of the NLRP3 inflammasome in wild-type mice promotes the progression of PD. The use of MCC950 in wild mice injected with LPS induces activation of Parkin/PINK and improves autophagy, which in turn improves mitochondrial turnover. It also inhibits LPS-induced inflammatory responses, improves motor function, protects dopaminergic neurons, and inhibits microglia activation. Furthermore, Parkin＋/－ mice exhibited motor dysfunction, loss of dopaminergic neurons, activation of the NLRP3 inflammasome, and α-Synuclein aggregation beginning at an early age. Parkin ± mice exhibited more pronounced microglia activation, greater NLRP3 inflammasome activation, more severe autophagy dysfunction, and more pronounced motor dysfunction after LPS injection compared to wild-type mice. Notably, the use of MCC950 in Parkin ± mice did not ameliorate NLRP3 inflammasome activation, autophagy dysfunction, or α-synuclein aggregation. Thus, MCC950 can only exert its effects in the presence of Parkin/PINK1, and targeting Parkin-mediated NLRP3 inflammasome activation is expected to be a potential therapeutic strategy for Parkinson's disease.

Phloroglucinol Derivatives Exert Anti-Inflammatory Effects and Attenuate Cognitive Impairment in LPS-Induced Mouse Model

Neuroinflammation is an inflammatory immune response that arises in the central nervous system. It is one of the primary causes of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Phloroglucinol (PG) is a natural product contained in extracts of plant, algae and microbe and has been reported to have antioxidant and anti-inflammatory properties. In this study, we synthesized PG derivatives to enhance antioxidant and anti-inflammatory activity. Among PG derivatives, 6 a suppressed pro-oxidative and inflammatory molecule nitric oxide (NO) production more effectively than PG. Moreover, 6 a dose-dependently reduced the expression of proinflammatory cytokines such as IL-6, IL-1β, TNF-α, and NO producing enzyme iNOS in lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. Additionally, we confirmed that 6 a alleviated cognitive impairment and glial activation in mouse model of LPS-induced neuroinflammation. These findings suggest that novel PG derivative, 6 a, is a potential treatment for neurodegenerative diseases.

The Synergistic Effect Study of Lipopolysaccharide (LPS) and A53T-α-Synuclein: Intranasal LPS Exposure on the A53T-α-Synuclein Transgenic Mouse Model of Parkinson's Disease

Aging and interactions between genetic and environmental factors are believed to be involved the chronic development of Parkinson's disease (PD). Among PD patients, abnormally aggregated α-synuclein is a major component of the Lewy body. Generally, the intranasal route is believed to be a gate way to the brain, and it assists environmental neurotoxins in entering the brain and is related to anosmia during early PD. The current study applies the chronic intranasal application of lipopolysaccharides (LPS) in 4-, 8-, 12- and 16-month-old A53T-α-synuclein (A53T-α-Syn) transgenic C57BL/6 mice at 2-day intervals for a 2-month period, for evaluating the behavioral, pathological, and biochemical changes and microglial activation in these animals. According to our results, after intranasal administration of LPS, A53T-α-Syn mice showed severe progressive anosmia, hypokinesia, selective dopaminergic (DAergic) neuronal losses, decreased striatal dopamine (DA) level, and enhanced α-synuclein accumulation within the substantia nigra (SN) in an age-dependent way. In addition, we found obvious NF-кB activation, Nurr1 inhibition, IL-1β, and TNF-α generation within the microglia of the SN. Conversely, the wild-type (WT) mice showed mild, whereas A53T-α-Syn mice had moderate PD-like changes among the old mice. This study demonstrated the synergistic effect of intranasal LPS and α-synuclein burden on PD development. Its underlying mechanism may be associated with Nurr1 inhibition within microglia and the amplification of CNS neuroinflammation. The mice with multiple factors, including aging, neuroinflammation, and α-synuclein mutation, have played a significant role in enhancing our understanding of how inflammation and α-synuclein mutation contribute to the neurodegeneration observed in PD.

Modelling the innate immune system in microphysiological systems

This critical review aims to highlight how modeling of the immune response has adapted over time to utilize microphysiological systems. Topics covered here will discuss the integral components of the immune system in various human body systems, and how these interactions are modeled using these systems. Through the use of microphysiological systems, we have not only expanded on foundations of basic immune cell information, but have also gleaned insight on how immune cells work both independently and collaboratively within an entire human body system.

Association between Physical Activity and Parkinson's Disease: A Prospective Cohort Study

BACKGROUND

The burden of Parkinson's disease (PD) is still increasing, and physical activity is a modifiable factor for health benefits. The benefits of physical activity in PD are not well established. Therefore, this study aimed to investigate the association between various types of physical activity and the risk of developing PD.

METHODS

Data from 432,497 participants in UK Biobank, who were free of PD at baseline, were analyzed. Physical activity levels were assessed by measuring the duration of walking for pleasure, light and heavy do-it-yourself (DIY) activities, strenuous sports, and other exercises. Physical activity was categorized into daily living activities (walking for pleasure, light DIY, and heavy DIY) and structured exercises (strenuous sports and other exercises). Association between different types of physical activity and PD risk was examined using multivariable adjusted restricted cubic splines and Cox proportional risk models.

RESULTS

Over a median follow-up of 13.7 years, 2,350 PD cases were identified. Cubic spline analyses revealed negative linear associations between PD risk and total physical activity, daily living activities, and structured exercise. After multivariable adjustment, the hazard ratios and 95% confidence intervals for incident PD associated with the highest quartile of total physical activity, daily living activities, and structured exercise were 0.72 (0.64-0.81), 0.75 (0.67-0.84), and 0.78 (0.67-0.90), respectively, compared to those in the lowest quartile. Sensitivity analysis confirmed these findings.

CONCLUSIONS

Higher levels of both daily living activities and structured exercise were associated with a reduced incidence of PD, underscoring the importance of maintaining physical activity to prevent PD.

Manganese and Vanadium Co-Exposure Induces Severe Neurotoxicity in the Olfactory System: Relevance to Metal-Induced Parkinsonism

Chronic environmental exposure to toxic heavy metals, which often occurs as a mixture through occupational and industrial sources, has been implicated in various neurological disorders, including Parkinsonism. Vanadium pentoxide (V2O5) typically presents along with manganese (Mn), especially in welding rods and high-capacity batteries, including electric vehicle batteries; however, the neurotoxic effects of vanadium (V) and Mn co-exposure are largely unknown. In this study, we investigated the neurotoxic impact of MnCl2, V2O5, and MnCl2-V2O5 co-exposure in an animal model. C57BL/6 mice were intranasally administered either de-ionized water (vehicle), MnCl2 (252 µg) alone, V2O5 (182 µg) alone, or a mixture of MnCl2 (252 µg) and V2O5 (182 µg) three times a week for up to one month. Following exposure, we performed behavioral, neurochemical, and histological studies. Our results revealed dramatic decreases in olfactory bulb (OB) weight and levels of tyrosine hydroxylase, dopamine, and 3,4-dihydroxyphenylacetic acid in the treatment groups compared to the control group, with the Mn/V co-treatment group producing the most significant changes. Interestingly, increased levels of α-synuclein expression were observed in the substantia nigra (SN) of treated animals. Additionally, treatment groups exhibited locomotor deficits and olfactory dysfunction, with the co-treatment group producing the most severe deficits. The treatment groups exhibited increased levels of the oxidative stress marker 4-hydroxynonenal in the striatum and SN, as well as the upregulation of the pro-apoptotic protein PKCδ and accumulation of glomerular astroglia in the OB. The co-exposure of animals to Mn/V resulted in higher levels of these metals compared to other treatment groups. Taken together, our results suggest that co-exposure to Mn/V can adversely affect the olfactory and nigral systems. These results highlight the possible role of environmental metal mixtures in the etiology of Parkinsonism.

Oral 8-aminoguanine against age-related retinal degeneration

Visual decline in the elderly is often attributed to retinal aging, which predisposes the tissue to pathologies such as age-related macular degeneration. Currently, effective oral pharmacological interventions for retinal degeneration are limited. We present a novel oral intervention, 8-aminoguanine (8-AG), targeting age-related retinal degeneration, utilizing the aged Fischer 344 rat model. A low-dose 8-AG regimen (5 mg/kg body weight) via drinking water, beginning at 22 months for 8 weeks, demonstrated significant retinal preservation. This was evidenced by increased retinal thickness, improved photoreceptor integrity, and enhanced electroretinogram responses. 8-AG effectively reduced apoptosis, oxidative damage, and microglial/macrophage activation associated with aging retinae. Age-induced alterations in the retinal purine metabolome, characterized by elevated levels of inosine, hypoxanthine, and xanthine, were partially mitigated by 8-AG. Transcriptomics highlighted 8-AG's anti-inflammatory effects on innate and adaptive immune responses. Extended treatment to 17 weeks further amplified the retinal protective effects. Moreover, 8-AG showed temporary protective effects in the RhoP23H/+ mouse model of retinitis pigmentosa, reducing active microglia/macrophages. Our study positions 8-AG as a promising oral agent against retinal aging. Coupled with previous findings in diverse disease models, 8-AG emerges as a promising anti-aging compound with the capability to reverse common aging hallmarks.

α-Synuclein oligomers potentiate neuroinflammatory NF-κB activity and induce Cav3.2 calcium signaling in astrocytes

BACKGROUND

It is now realized that Parkinson's disease (PD) pathology extends beyond the substantia nigra, affecting both central and peripheral nervous systems, and exhibits a variety of non-motor symptoms often preceding motor features. Neuroinflammation induced by activated microglia and astrocytes is thought to underlie these manifestations. α-Synuclein aggregation has been linked with sustained neuroinflammation in PD, aggravating neuronal degeneration; however, there is still a lack of critical information about the structural identity of the α-synuclein conformers that activate microglia and/or astrocytes and the molecular pathways involved.

METHODS

To investigate the role of α-synuclein conformers in the development and maintenance of neuroinflammation, we used primary quiescent microglia and astrocytes, post-mortem brain tissues from PD patients and A53T α-synuclein transgenic mice that recapitulate key features of PD-related inflammatory responses in the absence of cell death, i.e., increased levels of pro-inflammatory cytokines and complement proteins. Biochemical and -omics techniques including RNAseq and secretomic analyses, combined with 3D reconstruction of individual astrocytes and live calcium imaging, were used to uncover the molecular mechanisms underlying glial responses in the presence of α-synuclein oligomers in vivo and in vitro.

RESULTS

We found that the presence of SDS-resistant hyper-phosphorylated α-synuclein oligomers, but not monomers, was correlated with sustained inflammatory responses, such as elevated levels of endogenous antibodies and cytokines and microglial activation. Similar oligomeric α-synuclein species were found in post-mortem human brain samples of PD patients but not control individuals. Detailed analysis revealed a decrease in Iba1Low/CD68Low microglia and robust alterations in astrocyte number and morphology including process retraction. Our data indicated an activation of the p38/ATF2 signaling pathway mostly in microglia and a sustained induction of the NF-κB pathway in astrocytes of A53T mice. The sustained NF-κB activity triggered the upregulation of astrocytic T-type Cav3.2 Ca2+ channels, altering the astrocytic secretome and promoting the secretion of IGFBPL1, an IGF-1 binding protein with anti-inflammatory and neuroprotective potential.

CONCLUSIONS

Our work supports a causative link between the neuron-produced α-synuclein oligomers and sustained neuroinflammation in vivo and maps the signaling pathways that are stimulated in microglia and astrocytes. It also highlights the recruitment of astrocytic Cav3.2 channels as a potential neuroprotective mediator against the α-synuclein-induced neuroinflammation.

New fraternine analogues: Evaluation of the antiparkinsonian effect in the model of Parkinson's disease

Venom-derived peptides are important sources for the development of new therapeutic molecules, especially due to their broad pharmacological activity. Previously, our research group identified a novel natural peptide, named fraternine, with promising effects for the treatment of Parkinson's disease. In the present paper, we synthesized three peptides bioinspired in fraternine: fra-10, fra-14, and fra-24. They were tested in the 6-OHDA-induced model of parkinsonism, quantifying motor coordination, levels of TH+ neurons in the substantia nigra pars compacta (SN), and inflammation mediators TNF-α, IL-6, and IL-1ß in the cortex. Peptides fra-14 and fra-10 improved the motor coordination in relation to 6-OHDA lesioned animals. However, most of the peptides were toxic in the doses applied. All three peptides reduced the intensity of the lesion induced rotations in the apomorphine test. Fra-24 higher dose increased the number of TH+ neurons in SN and reduced the concentration of TNF-α in the cortex of 6-OHDA lesioned mice. Overall, only the peptide fra-24 presented a neuroprotection effect on dopaminergic neurons of SN and a reduction of cytokine TNF-α levels, making it worthy of consideration for the treatment of PD.

What Can Inflammation Tell Us about Therapeutic Strategies for Parkinson's Disease?

Parkinson's disease (PD) is a common neurodegenerative disorder with a complicated etiology and pathogenesis. α-Synuclein aggregation, dopaminergic (DA) neuron loss, mitochondrial injury, oxidative stress, and inflammation are involved in the process of PD. Neuroinflammation has been recognized as a key element in the initiation and progression of PD. In this review, we summarize the inflammatory response and pathogenic mechanisms of PD. Additionally, we describe the potential anti-inflammatory therapies, including nod-like receptor pyrin domain containing protein 3 (NLRP3) inflammasome inhibition, nuclear factor κB (NF-κB) inhibition, microglia inhibition, astrocyte inhibition, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibition, the peroxisome proliferator-activated receptor γ (PPARγ) agonist, targeting the mitogen-activated protein kinase (MAPK) pathway, targeting the adenosine monophosphate-activated protein kinase (AMPK)-dependent pathway, targeting α-synuclein, targeting miRNA, acupuncture, and exercise. The review focuses on inflammation and will help in designing new prevention strategies for PD.

Active ingredients of Chinese medicine with immunomodulatory properties: NF-κB pathway and Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease with a complex pathogenesis and no cure. Persistent neuroinflammation plays an important role in the development of PD, and activation of microglia and astrocytes within the central nervous system leads to an inflammatory response and production of pro-inflammatory factors, and activation of NF-κB is key to neuroglial activation in chronic inflammation in PD and a hallmark of the onset of neuroinflammatory disease. Therefore, inhibiting NF-κB activation to prevent further loss of dopaminergic nerves is a more effective means of treating PD. It has been found that an increasing number of active ingredients in Chinese medicines, such as flavonoids, alkaloids, saponins, terpenoids, phenols and phenylpropanoids, have anti-inflammatory properties that can regulate neuroglia cell activation and ameliorate neuroinflammation through the NF-κB pathway, and increase dopamine release or protect dopaminergic neurons for neuroprotection to improve behavioural dysfunction in PD. The active ingredients of traditional Chinese medicine are expected to be good candidates for the treatment of PD, as they provide holistic regulation through multi-targeting and multi-level effects, and are safe, inexpensive and readily available. Therefore, this paper summarises that the active ingredients of some relevant Chinese medicines ameliorate the symptoms of PD and delay the development of PD by inhibiting glial cell-mediated neuroinflammation through the NF-κB pathway, which may provide new ideas for exploring the molecular mechanism of PD pathogenesis and developing new anti-PD drugs.

Immunomodulatory and endocrine effects of deep brain stimulation and spinal cord stimulation - A systematic review

INTRODUCTION

Deep Brain Stimulation (DBS) and Spinal Cord Stimulation (SCS) represent burgeoning treatments for diverse neurological disorders. This systematic review aims to consolidate findings on the immunological and endocrine effects of DBS and SCS, shedding light on the intricate mechanisms of neuromodulation.

MATERIALS AND METHODS

This systematic review, aligned with PRISMA protocols, synthesizes findings from 33 references-20 on DBS and 13 on SCS-to unravel the immunological and endocrine impacts of neuromodulation.

RESULTS

DBS interventions exhibited divergent effects on cytokines, with an increase in hepcidin levels and a variable impact on the IL-6/IL-10 ratio. While some studies reported elevated IL-6, animal studies consistently demonstrated a reduction in IL-1β and IL-6, with no significant changes in TNF-α and an increase in IL-10. Noteworthy hormonal changes included decreased corticosterone and ACTH concentrations and increased oxytocin levels following DBS of the hypothalamus. SCS mirrored similar effects on interleukins, indicating a reduction in IL-6 and IL-1β and an increase in IL-10 levels. Additionally, SCS led to reduced VEGF levels and elevated expression of neurotrophic factors such as BDNF and GDNF, particularly under burst stimulation.

CONCLUSIONS

Both DBS and SCS exert anti-inflammatory effects, manifesting as a decrease in pro-inflammatory cytokines alongside the stimulation of anti-inflammatory cytokine synthesis. These findings, observed in both animal and human models, imply that neurostimulation may modify the trajectory of neurological diseases by modulating local immune responses in an immunomodulatory and endocrine manner. This comprehensive exploration sets the stage for future research endeavors in this evolving domain.

Neuroprotective effects of an engineered Escherichia coli Nissle 1917 on Parkinson's disease in mice by delivering GLP-1 and modulating gut microbiota

Considerable evidence suggests that insulin resistance is closely linked to Parkinson's disease (PD), leading to agents aiming at treating diabetes can be regarded as new neuroprotective strategies in PD, notably glucagon-like peptide-1 (GLP-1). However, the extremely short half-life of GLP-1 due to degradation by the ubiquitous proteolytic enzyme limits its clinical application. In this study, we engineered the recombinant integrant probiotic strain Escherichia coli Nissle 1917 (EcN) to create a strain EcN-GLP-1 that effectively delivers the heterologous GLP-1 molecule. Subsequently, we assessed its neuroprotective effects on 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced PD mice. We demonstrated that EcN-GLP-1 treatment could improve motor deficits, increase tyrosine hydroxylase-positive neurons, suppress microglia and astrocyte activation, reduce brain and colon inflammation, and ameliorate colonic barrier function damaged by MPTP induction. Meanwhile, we confirmed that the oral administration of EcN-GLP-1 could restore the disturbance of gut microbiota in the MPTP-induced PD mice, by reducing the relative abundances of Akkermansia and Oscillospira, and increasing the level of Prevotella in the gut. These results support further development of an engineered probiotic platform in which production of GLP-1 for gut-brain disorders, such as PD.

Animal models of Parkinson's disease: bridging the gap between disease hallmarks and research questions

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. More than 200 years after its first clinical description, PD remains a serious affliction that affects a growing proportion of the population. Prevailing treatments only alleviate symptoms; there is still neither a cure that targets the neurodegenerative processes nor therapies that modify the course of the disease. Over the past decades, several animal models have been developed to study PD. Although no model precisely recapitulates the pathology, they still provide valuable information that contributes to our understanding of the disease and the limitations of our treatment options. This review comprehensively summarizes the different animal models available for Parkinson's research, with a focus on those induced by drugs, neurotoxins, pesticides, genetic alterations, α-synuclein inoculation, and viral vector injections. We highlight their characteristics and ability to reproduce PD-like phenotypes. It is essential to realize that the strengths and weaknesses of each model and the induction technique at our disposal are determined by the research question being asked. Our review, therefore, seeks to better aid researchers by ensuring a concrete discernment of classical and novel animal models in PD research.

Deep brain stimulation improves central nervous system inflammation in Parkinson's disease: Evidence and perspectives

BACKGROUND

In Parkinson's disease (PD), inflammation may lead to the degeneration of dopaminergic (DAergic) neurons. Previous studies showed that inflammatory mediators mainly contributed to this phenomenon. On the other hand, invasive neuromodulation methods such as deep brain stimulation (DBS) have better therapeutic effects for PD. One possibility is that DBS improves PD by influencing inflammation. Therefore, we further explored the mechanisms underlying inflammatory mediators and DBS in the pathogenesis of PD.

METHODS

We measured serum levels of two inflammatory markers, namely RANTES (regulated on activation, normal T cell expressed and secreted) and tumor necrosis factor-alpha (TNF-α), using Luminex assays in 109 preoperative DBS PD patients, 49 postoperative DBS PD patients, and 113 age- and sex-matched controls. The plasma protein data of the different groups were then statistically analyzed.

RESULTS

RANTES (p < 0.001) and TNF-α (p = 0.005) levels differed significantly between the three groups. A strong and significant correlation between RANTES levels and Hoehn-Yahr (H-Y) stage was observed in preoperative PD patients (r_s  = 0.567, p < 0.001). Significant correlations between RANTES levels and Unified Parkinson's Disease Rating Scale III (UPDRS III) score (r_s1  = 0.644, p = 0.033 and r_s2  = 0.620, p = 0.042) were observed in matched patients. No correlation was observed for TNF-α levels.

CONCLUSION

The results of this study indicate that PD patients have a persistent inflammatory profile, possibly via recruitment of activated monocytes, macrophages, and T lymphocytes to the central nervous system (CNS). DBS was shown to have a significant therapeutic effect on PD, which may arise by improving the inflammatory environment of the central nervous system.

Rhynchophylline alleviates neuroinflammation and regulates metabolic disorders in a mouse model of Parkinson's disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder with limited therapeutic agents. Rhynchophylline (RIN), a tetracyclic oxindole alkaloid isolated from Uncaria rhynchophylla, has multiple neuropharmacological activities, including anti-inflammatory, anti-depression, anti-neurodegenerative disease, and anti-drug addiction. Though it is reported that RIN exerts a neuroprotective effect against PD, the underlying protective mechanism remains obscure. In this study, a mass spectrometry-based metabolomic strategy combined with neurobehavioral tests, serum biochemical assays, and immunohistochemistry were employed to decipher the protective mechanism of RIN against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced subacute PD in mice. Our results indicated that RIN significantly improved the MPTP-induced behavioral abnormalities, reduced the loss of dopaminergic neurons, and reversed the secretion of inflammatory cytokines and oxidative stress indicators. Further studies showed that RIN significantly suppressed the expression of toll-like receptor 4, NOD-like receptor protein 3, and cyclooxygenase 2 in the mouse striatum. The results of serum metabolomics showed that RIN could ameliorate metabolic disorders in PD mainly through the regulation of retinol metabolism, arachidonic acid metabolism, glycerophospholipid metabolism, and purine metabolism. These pieces of evidence revealed that RIN is a promising drug candidate for PD by alleviating neuroinflammation and maintaining metabolic homeostasis.

Voltage-Gated Proton Channel Hv1 Regulates Neuroinflammation and Dopaminergic Neurodegeneration in Parkinson's Disease Models

Although the precise mechanisms for neurodegeneration in Parkinson's disease (PD) are unknown, evidence suggests that neuroinflammation is a critical factor in the pathogenic process. Here, we sought to determine whether the voltage-gated proton channel, Hv1 (HVCN1), which is expressed in microglia and regulates NADPH oxidase, is associated with dopaminergic neurodegeneration. We utilized data mining to evaluate the mRNA expression of HVCN1 in the brains of PD patients and controls and uncovered increased expression of the gene encoding Hv1, HVCN1, in the brains of PD patients compared to controls, specifically in male PD patients. In an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 4 × 16 mg/kg) mouse model of PD, Hvcn1 gene expression was increased 2-fold in the striatum. MPTP administration to wild-type (WT) mice resulted in a ~65% loss of tyrosine hydroxylase positive neurons (TH+) in the substantia nigra (SN), while a ~39% loss was observed in Hv1 knockout (KO) mice. Comparable neuroprotective effects of Hv1 deficiency were found in a repeated-dose LPS model. Neuroprotection was associated with decreased pro-inflammatory cytokine levels and pro-oxidant factors in both neurotoxicant animal models. These in vivo results were confirmed in primary microglial cultures, with LPS treatment increasing Hvcn1 mRNA levels and Hv1 KO microglia failing to exhibit the LPS-mediated inflammatory response. Conditioned media from Hv1 KO microglia treated with LPS resulted in an attenuated loss of cultured dopamine neuron cell viability compared to WT microglia. Taken together, these data suggest that Hv1 is upregulated and mediates microglial pro-inflammatory cytokine production in parkinsonian models and therefore represents a novel target for neuroprotection.

Short bouts of walking attenuates the response of IL-8 to prolonged sitting in healthy adults

PURPOSE

Experimental studies have shown that prolonged sitting for 2-8 h can cause changes to vascular and metabolic markers; the response of pro-inflammatory cytokines is relatively unexplored. The purpose of this study is to determine the response of interleukin-8 (IL-8) to prolonged and interrupted sitting.

METHODS

Healthy participants (n = 24, 21.1 years ± 2.2, 50% female) completed a prolonged sitting session (4 h) and an interrupted sitting session (4 h of sitting with 3 min of walking at 60%HRmax, every 30 min) in random order. Saliva and capillary plasma were collected at the beginning (T1) and at the end of each session (T2).

RESULTS

Salivary concentrations of IL-8 increased during the prolonged (T1 median: 22.09 pg/mL, T2 median: 86.18 pg/mL; p =  < 0.01, ES - 0.55) and interrupted (T1 median: 22.09 pg/mL, T2 median: 51.99 pg/mL; p = 0.021, ES - 0.34) sessions; however, the increase during interrupted sitting was lower (PS median: 134.4%, range: - 43.96 to 1115.69 and IS median: 50.8%, range: - 75.5 to 356.35; p = 0.011, ES - 0.53). In the sub-sample of males, salivary IL-8 did not increase in the interrupted session (T1 median: 22.09, range: 3.496-699.12, and T2 median: 24.96, range: 5.11-533.5, p =  > 0.05, ES - 0.16). No significant findings were observed for IL-8 in the plasma.

CONCLUSION

Prolonged sitting appears to increase concentrations of the pro-inflammatory cytokine IL-8 while interrupting this sitting with short bouts of walking blunts this response. Sex appears to moderate this relationship; however, there appears to be a large amount of individual variability.

A systematic review and meta-analysis of inflammatory biomarkers in Parkinson's disease

Neuroinflammation plays a crucial role in the pathogenesis of Parkinson's disease (PD), but controversies persist. Studies reporting concentrations of blood or cerebrospinal fluid (CSF) markers for patients with PD and controls were included and extracted. Pooled Hedges'g was adopted to illustrate comparisons, and covariates were used to explore sources of heterogeneity. Finally, 152 studies were included. Increased IL-6, TNF-α, IL-1β, STNFR1, CRP, CCL2, CX3CL1, and CXCL12 levels and decreased INF-γ and IL-4 levels were noted in the PD group. In addition, increased CSF levels of IL-6, TNF-α, IL-1β, CRP and CCL2 were revealed in patients with PD compared to controls. Consequently, significantly altered levels of inflammatory markers were verified between PD group and control, suggesting that PD is accompanied by inflammatory responses in both the peripheral blood and CSF. This study was registered with PROSPERO, CRD42022349182.

Early approaches of YKL-40 as a biomarker and therapeutic target for Parkinson's disease

Aim: To investigate whether the estimation of cerebrospinal fluid (CSF) and brain YKL-40 levels may be used as an efficient biomarker for Parkinson's disease (PD). Methods: Lipopolysaccharides (LPS) was injected into the right substantia nigra pars compacta (SNpc). Rats were divided into: control group, early LPS-induced PD group (14 days), and advanced LPS-induced PD group (28 days). YKL-40 and other related factors were detected in CSF and brain tissue. Results: Increased expression of YKL-40 was observed in brain tissue and CSF of PD-induced rats associated with triggered inflammatory cytokine release. Conclusion: The current study was limited to detecting YKL-40 and other inflammatory factors in brain and CSF. YKL-40 may be considered as an early biomarker and therapeutic target for PD.

Transcriptional and epigenetic regulation of microglia in maintenance of brain homeostasis and neurodegeneration

The emerging role of microglia in brain homeostasis, neurodegeneration, and neurodevelopmental disorders has attracted considerable interest. In addition, recent developments in microglial functions and associated pathways have shed new light on their fundamental role in the immunological surveillance of the brain. Understanding the interconnections between microglia, neurons, and non-neuronal cells have opened up additional avenues for research in this evolving field. Furthermore, the study of microglia at the transcriptional and epigenetic levels has enhanced our knowledge of these native brain immune cells. Moreover, exploring various facets of microglia biology will facilitate the early detection, treatment, and management of neurological disorders. Consequently, the present review aimed to provide comprehensive insight on microglia biology and its influence on brain development, homeostasis, management of disease, and highlights microglia as potential therapeutic targets in neurodegenerative and neurodevelopmental diseases.

Zebrafish: A Model Deciphering the Impact of Flavonoids on Neurodegenerative Disorders

Over the past century, advances in biotechnology, biochemistry, and pharmacognosy have spotlighted flavonoids, polyphenolic secondary metabolites that have the ability to modulate many pathways involved in various biological mechanisms, including those involved in neuronal plasticity, learning, and memory. Moreover, flavonoids are known to impact the biological processes involved in developing neurodegenerative diseases, namely oxidative stress, neuroinflammation, and mitochondrial dysfunction. Thus, several flavonoids could be used as adjuvants to prevent and counteract neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Zebrafish is an interesting model organism that can offer new opportunities to study the beneficial effects of flavonoids on neurodegenerative diseases. Indeed, the high genome homology of 70% to humans, the brain organization largely similar to the human brain as well as the similar neuroanatomical and neurochemical processes, and the high neurogenic activity maintained in the adult brain makes zebrafish a valuable model for the study of human neurodegenerative diseases and deciphering the impact of flavonoids on those disorders.

Anti-neuroinflammatory Effects and Brain Pharmacokinetic Properties of Selonsertib, an Apoptosis signal-regulating Kinase 1 Inhibitor, in mice

Selonsertib is a first-in-class apoptosis signal-regulating kinase 1 (ASK1) inhibitor in clinical trials for treating NASH and diabetic kidney disease due to its anti-inflammatory and anti-fibrotic activities. In the present study, we investigated the anti-neuroinflammatory effects and brain pharmacokinetic properties of selonsertib. It inhibited inflammatory cytokines and NO production by suppressing phosphorylated ASK1 in the LPS-stimulated microglial cell line, BV2 cells. Consistent with the in vitro results, selonsertib attenuated plasma and brain TNF-α levels in the LPS-induced murine neuroinflammation model. In vitro and in vivo pharmacokinetic studies of selonsertib were conducted in support of central nervous system (CNS) drug discovery. In both Caco-2 and MDR-MDCK cells, selonsertib exhibited a high efflux ratio, showing that it is a P-gp substrate. Selonsertib was rapidly and effectively absorbed into the systemic circulation after oral treatment, with a T_max of 0.5 h and oral bioavailability of 74%. In comparison with high systemic exposure with C_max of 16.2 µg/ml and AUC of 64 µg·h/mL following oral dosing of 10 mg/kg, the brain disposition of selonsertib was limited, with C_max of 0.08 µg/g and Kp value of 0.004. This study demonstrates that selonsertib can be a therapeutic agent for neuroinflammatory diseases.

New Insights into the Gut Microbiota in Neurodegenerative Diseases from the Perspective of Redox Homeostasis

An imbalance between oxidants and antioxidants in the body can lead to oxidative stress, which is one of the major causes of neurodegenerative diseases. The gut microbiota contains trillions of beneficial bacteria that play an important role in maintaining redox homeostasis. In the last decade, the microbiota-gut-brain axis has emerged as a new field that has revolutionized the study of the pathology, diagnosis, and treatment of neurodegenerative diseases. Indeed, a growing number of studies have found that communication between the brain and the gut microbiota can be accomplished through the endocrine, immune, and nervous systems. Importantly, dysregulation of the gut microbiota has been strongly associated with the development of oxidative stress-mediated neurodegenerative diseases. Therefore, a deeper understanding of the relationship between the gut microbiota and redox homeostasis will help explain the pathogenesis of neurodegenerative diseases from a new perspective and provide a theoretical basis for proposing new therapeutic strategies for neurodegenerative diseases. In this review, we will describe the role of oxidative stress and the gut microbiota in neurodegenerative diseases and the underlying mechanisms by which the gut microbiota affects redox homeostasis in the brain, leading to neurodegenerative diseases. In addition, we will discuss the potential applications of maintaining redox homeostasis by modulating the gut microbiota to treat neurodegenerative diseases, which could open the door for new therapeutic approaches to combat neurodegenerative diseases.

Long noncoding RNA SNHG14 knockdown exerts a neuroprotective role in MPP+-induced Parkinson's disease cell model through mediating miR-135b-5p/KPNA4 axis

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disease resulted from the loss of dopaminergic neurons. Here, we analyzed the role of long noncoding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) in PD using 1-methyl-4-phenyl pyridine (MPP⁺)-induced PD cell model.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were performed to determine RNA and protein expression, respectively. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry (FCM) analysis were conducted to analyze cell viability and apoptosis. Enzyme-Linked Immunosorbent Assay (ELISA) was conducted to analyze the release of inflammatory cytokines. Cytotoxicity was assessed using reactive oxygen species (ROS) assay kit, superoxide dismutase (SOD) activity assay kit and lactate dehydrogenase (LDH) activity assay kit. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were performed to confirm the interaction between microRNA-135b-5p (miR-135b-5p) and SNHG14 or karyopherin subunit alpha 4 (KPNA4).

RESULTS

MPP⁺ treatment elevated the expression of SNHG14 in SK-N-SH cells in a dose and time-dependent manner. SNHG14 knockdown alleviated MPP⁺-induced apoptosis, inflammation, and cytotoxicity in SK-N-SH cells. SNHG14 interacted with miR-135b-5p, and SNHG14 silencing-mediated effects were partly overturned by miR-135b-5p knockdown in PD cell model. Besides, miR-135b-5p interacted with the 3' untranslated region (3'UTR) of KPNA4, and KPNA4 overexpression partly reversed miR-135b-5p overexpression-induced effects in PD cell model. SNHG14 knockdown reduced the protein level of KPNA4 partly by up-regulating miR-135b-5p in SK-N-SH cells.

CONCLUSION

SNHG14 promoted MPP⁺-induced neuro injury in PD cell model through mediating miR-135b-5p/KPNA4 axis.

Increased PRR14 and VCAM-1 level in serum of patients with Parkinson's disease

Background

Regarding the complexity of Parkinson's disease (PD), the identification of reliable biomarkers is of great significance for improving the accuracy of diagnosis and monitoring disease progression. Recently, some studies suggested that serum proline-rich protein 14 (PRR14), vascular cell adhesion molecule-1 (VCAM-1), and soluble CD163 (sCD163) factors may be associated with PD, even as potential biomarkers. However, the role of these serum factors is still unclear.

Objectives

This study aimed to explore the alterations of serum PRR14, VCAM-1, and sCD163 levels during PD progression, and their association with disease-related variables of PD.

Methods

We performed the assessment of scale tests and the detection of serum samples in patients with PD (n = 100) and healthy controls (HCs, n = 100). Furthermore, we investigated the association between serum factors and sex, cognitive impairments, H&Y (Hohn and Yahr), age at onset (AAO), and other variables in patients with PD.

Results

Patients with PD exhibited increased PRR14 and VCAM-1 serum levels compared with HCs. No significant differences were found in serum levels of sCD163. Subgroup analysis uncovered increased VCAM-1 in the female and male subgroups (PD and HCs). Among patients with PD, decreased PRR14 and increased VCAM-1 were associated with severer cognitive impairments and severer PD (H&Y), respectively. Bivariate correlation analysis revealed that there was a positive correlation between VCAM-1 and AAO.

Conclusions

Increased serum levels of PRR14 and VCAM-1 suggest that inflammation and defective autophagy may play vital roles in the pathogenesis of PD. However, the potential mechanisms remain to be elucidated.

Potential Molecular Mechanism of Guishao Pingchan Recipe in the Treatment of Parkinson’s Disease Based on Network Pharmacology and Molecular Docking

Objective: To investigate the potential mechanism of Guishao Pingchan Recipe (GPR) against Parkinson's disease (PD) based on network pharmacology and molecular docking. Methods: The main components of GPR were collected based on TCMSP database, Batman-TCM database, Chinese Pharmacopoeia, and Literatures. The potential therapeutic targets of PD were predicted by Drug Bank Database and Gene Cards database. Cytoscape 3.8.2 software was used to construct herb–component–target network. Then, String database was used to construct a PPI network, and DAVID database was used for gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation of targets function. Core components of GPR and hub targets were imported into AutoDock Vina for molecular docking verification and results were visualized by Pymol. Results: 13 candidate components were selected and 288 corresponding targets of GPR for treating PD were obtained. The GO enrichment analysis mainly involved 135 cell components, 187 molecular functions, and 1753 biological processes. Moreover, KEGG pathway enrichment analysis mainly involved 200 signaling pathways. Molecular docking simulation indicated a good binding ability of components and targets. Conclusion: Based on network pharmacology and molecular docking, we found that sitosterol, 4-Cholesten-3-one and stigmasterol in GPR could combine with MAPK3, APP, VEGFA, and CXCR4 and involved in the cAMP, PI3K/Akt, Rap1 signaling pathways. It is suggested that GPR may have therapeutic effects on PD through multi-component, multi-target, and multi-pathway and predict the relevant mechanism of the anti-PD effect of GPR.

Parkinson's disease peripheral immune biomarker profile: a multicentre, cross-sectional and longitudinal study

BACKGROUND

Inflammations play crucial role in the pathogenesis of Parkinson's disease (PD), however, their possible value in the diagnosis or tracking of the progress of PD is still limited, because of discordant results in the literature and a lack of information regarding its reproducibility. Thus, overall longitudinal and cross-sectional studies are needed. This multicentre study was designed to investigate the association between multiple peripheral immune biomarkers and the development and progression of PD.

METHODS

This was a longitudinal and multicentre study. First, we measured the levels of five typical cytokines and five focused chemokines in 76 PD patients and 76 healthy controls (HCs) in a discovery cohort. Then, a validation cohort of 80 PD and 80 HC participants was recruited from four multicentre locations. In addition, a prospective follow-up of early-stage PD patients was performed with significant biomarkers. Finally, we performed further verification in an exploratory set of patients with idiopathic REM sleep behaviour disorder (iRBD).

RESULTS

In the discovery set, CXCL12, CX3CL1 and IL-8 levels were significantly higher in PD patients than in HCs (p < 0.05). The receiver-operating characteristic (ROC) curve for a combination of these three biomarkers produced a high area under the curve (AUC) of 0.89 (p < 0.001). Moreover, four biomarkers (the previous three and CCL15) were significantly associated with PD in the discovery and validation cohorts. Furthermore, in the prospective follow-up cohort, CX3CL1 levels were associated with motor progression after a mean interval of 43 months. In addition, CX3CL1 and IL-8 levels were higher in iRBD patients than in HCs.

CONCLUSION

We showed a correlation between a profile of four peripheral immune biomarkers and PD development and progression. Our findings may provide a basis whereby PD patients with abnormal inflammatory profiles can be identified and receive timely therapeutic interventions.

Microvascular Changes in Parkinson’s Disease- Focus on the Neurovascular Unit

Vascular alterations emerge as a common denominator for several neurodegenerative diseases. In Parkinson’s disease (PD), a number of observations have been made suggesting that the occurrence of vascular pathology is an important pathophysiological aspect of the disease. Specifically, pathological activation of pericytes, blood-brain barrier (BBB) disruption, pathological angiogenesis and vascular regression have been reported. This review summarizes the current evidence for the different vascular alterations in patients with PD and in animal models of PD. We suggest a possible sequence of vascular pathology in PD ranging from early pericyte activation and BBB leakage to an attempt for compensatory angiogenesis and finally vascular rarefication. We highlight different pathogenetic mechanisms that play a role in these vascular alterations including perivascular inflammation and concomitant metabolic disease. Awareness of the contribution of vascular events to the pathogenesis of PD may allow the identification of targets to modulate those mechanisms. In particular the BBB has for decades only been viewed as an obstacle for drug delivery, however, preservation of its integrity and/or modulation of the signaling at this interface between the blood and the brain may prove to be a new avenue to take in order to develop disease-modifying strategies for neurodegenerative disorders.

Microglia Activation in the Midbrain of the Human Neonate: The Effect of Perinatal Hypoxic-Ischemic Injury

Perinatal hypoxia-ischemia (PHI) is a major risk factor for the development of neuropsychiatric deficits later in life. We previously reported that after prolonged PHI, the dopaminergic neurons of the human neonate showed a dramatic reduction of tyrosine hydroxylase (TH) in the substantia nigra, without important signs of neuronal degeneration despite the significant reduction in their cell size. Since microglia activation could precede neuronal death, we now investigated 2 microglia activation markers, ionized calcium-binding adapter molecule 1 (Iba1), and the phagocytosis marker Cd68. The highest Iba1 immunoreactivity was found in neonates with neuropathological lesions of severe/abrupt PHI, while the lowest in subjects with moderate/prolonged or older PHI. Subjects with very severe/prolonged or chronic PHI showed an increased Iba1 expression and very activated microglial morphology. Heavy attachment of microglia on TH neurons and remarkable expression of Cd68 were also observed indicating phagocytosis in this group. Females appear to express more Iba1 than males, suggesting a gender difference in microglia maturation and immune reactivity after PHI insult. PHI-induced microglial "priming" during the sensitive for brain development perinatal/neonatal period, in combination with genetic or other epigenetic factors, could predispose the survivors to neuropsychiatric disorders later in life, possibly through a sexually dimorphic way.

Role of exosomes in the pathogenesis of inflammation in Parkinson's disease

Inflammatory responses, including glial cell activation and peripheral immune cell infiltration, are involved in the pathogenesis of Parkinson’s disease (PD). These inflammatory responses appear to be closely related to the release of extracellular vesicles, such as exosomes. However, the relationships among different forms of glial cell activation, synuclein dysregulation, mitochondrial dysfunction, and exosomes are complicated. This review discusses the multiple roles played by exosomes in PD-associated inflammation and concludes that exosomes can transport toxic α-synuclein oligomers to immature neurons and into the extracellular environment, inducing the oligomerization of α-synuclein in normal neurons. Misfolded α-synuclein causes microglia and astrocytes to activate and secrete exosomes. Glial cell-derived exosomes participate in communications between glial cells and neurons, triggering anti-stress and anti-inflammatory responses, in addition to axon growth. The production and release of mitochondrial vesicles and exosomes establish a new mechanism for linking mitochondrial dysfunction to systemic inflammation associated with PD. Given the relevance of exosomes as mediators of neuron-glia communication in neuroinflammation and neuropathogenesis, new targeted treatment strategies are currently being developed that use these types of extracellular vesicles as drug carriers. Exosome-mediated inflammation may be a promising target for intervention in PD patients.

Inflammasome Signaling in the Aging Brain and Age-Related Neurodegenerative Diseases

Inflammasomes are intracellular protein complexes, members of the innate immune system, and their activation and regulation play an essential role in maintaining homeostatic conditions against exogenous and endogenous stimuli. Inflammasomes occur as cytosolic proteins and assemble into a complex during the recognition of pathogen-associated or danger-associated molecular patterns by pattern-recognition receptors in host cells. The formation of the inflammasome complex elicits signaling molecules of proinflammatory cytokines such as interleukin-1β and interleukin 18 via activation of caspase-1 in the canonical inflammasome pathway whereas caspase-11 in the case of a mouse and caspase-4 and caspase-5 in the case of humans in the non-canonical inflammasome pathway, resulting in pyroptotic or inflammatory cell death which ultimately leads to neuroinflammation and neurodegenerative diseases. Inflammasome activation, particularly in microglial cells and macrophages, has been linked to aging as well as age-related neurodegenerative diseases. The accumulation of abnormal/ misfolded proteins acts as a ligand for inflammasome activation in neurodegenerative diseases. Although recent studies have revealed the inflammasomes' functionality in both in vitro and in vivo models, many inflammasome signaling cascade activations during biological aging, neuroinflammation, and neurodegeneration are still ambiguous. In this review, we comprehensively unveil the cellular and molecular mechanisms of inflammasome activation during neuronal aging and age-related neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, prion disease, and amyotrophic lateral sclerosis.

Stem Cell Transplantation Therapy and Neurological Disorders: Current Status and Future Perspectives

Neurodegenerative diseases are a global health issue with inadequate therapeutic options and an inability to restore the damaged nervous system. With advances in technology, health scientists continue to identify new approaches to the treatment of neurodegenerative diseases. Lost or injured neurons and glial cells can lead to the development of several neurological diseases, including Parkinson's disease, stroke, and multiple sclerosis. In recent years, neurons and glial cells have successfully been generated from stem cells in the laboratory utilizing cell culture technologies, fueling efforts to develop stem cell-based transplantation therapies for human patients. When a stem cell divides, each new cell has the potential to either remain a stem cell or differentiate into a germ cell with specialized characteristics, such as muscle cells, red blood cells, or brain cells. Although several obstacles remain before stem cells can be used for clinical applications, including some potential disadvantages that must be overcome, this cellular development represents a potential pathway through which patients may eventually achieve the ability to live more normal lives. In this review, we summarize the stem cell-based therapies that have been explored for various neurological disorders, discuss the potential advantages and drawbacks of these therapies, and examine future directions for this field.

Dopaminergic neuronal death in the substantia nigra associates with change in serum levels of TNF-α and IL-1β; evidence from early experimental model of Parkinson's disease

PURPOSE

Studies have shown that inflammation plays a key role in etiology of Parkinson's disease (PD). However, human studies which have evaluated association between PD and serum levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) have reported conflicting results. In this study, serum and striatum levels of these cytokines were evaluated in 6-hydroxydopamine (6-OHDA) animal model of PD.

METHOD

The neurotoxin of 6-OHDA was injected into medial forebrain bundle of right hemisphere and behavioral tests were carried out to eight weeks thereafter to evaluate severity of PD and its progress. Blood was collected before the toxin and in second and eight weeks after that. Survival of dopaminergic (DAergic) neurons in substantia nigra was assessed by immunohistochemistry. TNF-α and IL-1β levels were determined using ELISA kits.

RESULT

Severity of behavioral symptoms was gradually increased in 6-OHDA-treated rats. They showed a decrease in serum TNF-α level in the eight week and increase in IL-1β both in the second and eight weeks. They were divided into two subgroups, symptomatic and asymptomatic with severe and moderate degrees in DAergic neuronal death. Significant decrease in serum TNF-α was only observed in the symptomatic subgroup but IL-1β increased in both subgroups. Also, striatal levels of both cytokines were higher in the lesioned hemisphere.

CONCLUSION

Increase in serum IL-1β level can reflect moderate degree of lesion in substantia nigra and thereby is used for prognosis of PD before its clinical symptoms are appeared. On the other hand, an increase in serum TNF-α is appeared in advanced stage of PD.

If Not Insulin Resistance so What? - Comparison of Fasting Glycemia in Idiopathic Parkinson's Disease and Atypical Parkinsonism

BACKGROUND

Parkinson's disease (PD) is a synucleinopathy, which presents dysautonomia, as its common non-motor symptom. Some research suggests the existing interplay between the autonomic nervous system dysfunction and glucose metabolism dysregulation in PD.

OBJECTIVE

To determine the prevalence of metabolic disorders with particular emphasis on glucose metabolism in patients with PD and atypical parkinsonism (AP).

PATIENTS AND METHODS

A retrospective study was performed by analyzing 461 clinical data of consecutive patients diagnosed with PD, multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) hospitalized from 2019 to 2021 in the authors' institution. The study group included 350 patients (303 PD, 14 MSA, 33 PSP), aged 65.8 ± 9.7 years (42% were female). Laboratory results (fasting glycemia, lipid parameters, TSH, homocysteine and vitamin D3 levels) were collected. The patient's clinical condition was assessed in III part of Unified Parkinson's Disease Rating Scale (UPDRS p. III), Hoehn-Yahr scale, Mini Mental State Examination (MMSE) and Beck Depression Inventory (BDI).

RESULTS

Impaired fasting glycemia (IGF) was more prevalent in PD than in the PSP (43.43% vs 18.18%; p = 0.043). Similarly, PD presented a higher level of fasting glycemia (102.4 ± 16.7 mg/dl vs 92.2 ± 16.1mg/dl; p = 0.042). According to lipid parameters, patients with PD showed lower LDL cholesterol (92.3 ± 44.3mg/dl vs 119 ± 61.0mg/dl; p = 0.016) and lower BMI compared to patients with PSP (26.1 ± 4.0kg/m² vs 29.3 ± 4.4 kg/m²; p = 0.024), but there were no statistically significant differences in triglycerides (TG) and HDL cholesterol levels. Males with PD presented greater frequency of IFG (35.05% vs 50.6%; p = 0.042), higher fasting glycemia (99.1 ± 14.3mg/dl vs 103.7 ± 14.7mg/dl; p = 0.006), lower total cholesterol, HDL cholesterol, and BMI compared to women with PD.

CONCLUSION

Our investigation supports an association between synucleinopathies and glucose metabolism dysregulation.

Preventive Efficiency of Chelidonium majus Ethanolic Extract Against Aflatoxin B1 Induced Neurochemical Deteriorations in Rats

&lt;b&gt;Background and Objective:&lt;/b&gt; Aflatoxins affect many species including humans and animals, therefore the present study was designed to investigate the protective effect of &lt;i&gt;Chelidonium majus&lt;/i&gt; Ethanolic Extract (CMEE) on neurotoxicity induced by Aflatoxin B&lt;sub&gt;1&lt;/sub&gt; (AFB1) in rats. &lt;b&gt;Materials and Methods:&lt;/b&gt; Four groups of male Albino rats were treated orally for 28 days as follows: (1) Control group was daily given DMSO-PBS buffer (1.0 mL per rat), (2) CMEE (300 mg kg&lt;sup&gt;1&lt;/sup&gt;/day) dissolved in DMSO-PBS buffer, (3) AFB1 (80 μg kg&lt;sup&gt;1&lt;/sup&gt;/day) dissolved in DMSO-PBS buffer and (4) Received daily AFB1 (300 mg kg&lt;sup&gt;1&lt;/sup&gt;) in combination with CMEE (300 mg kg&lt;sup&gt;1&lt;/sup&gt;). &lt;b&gt;Results:&lt;/b&gt; CMEE exhibits antioxidant activity &lt;i&gt;in vitro&lt;/i&gt; and neuroameliorative efficiency &lt;i&gt;in vivo&lt;/i&gt; as its administration in combination with AFB1 succeeded significantly in down regulating the elevated levels of inflammatory and apoptotic markers and restoring the values of neurochemical markers (AChE-ase, dopamine and serotonin) that were deteriorated by AFB1 intake. &lt;b&gt;Conclusion:&lt;/b&gt; In conclusion, the neuroprotective effect of CMEE may be mediated through its antioxidant and free radical scavenging activity that proved from the data&lt;i&gt; &lt;/i&gt;of ferric-reducing power ability and DPPH radical scavenging activity.

Psychobiotics improve propionic acid-induced neuroinflammation in juvenile rats, rodent model of autism

This study aimed to evaluate the protective and therapeutic potency of bee pollen and probiotic mixture on brain intoxication caused by propionic acid (PPA) in juvenile rats. Five groups of six animals each, were used: the control group only receiving phosphate-buffered saline; the bee pollen and probiotic-treated group receiving a combination of an equal quantity of bee pollen and probiotic (0.2 kg/kg body weight); the PPA group being treated for 3 days with an oral neurotoxic dose of PPA (0.25 kg/kg body weight); the protective and therapeutic groups receiving bee pollen and probiotic mixture treatment right before and after the neurotoxic dose of PPA, respectively. The levels of interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor α, and interferon γ (IFN-γ) were investigated to evaluate the neuroinflammatory responses in brain tissues from different animal groups. The much higher IL-1β, IL-8, and IFN-γ, as pro-inflammatory cytokines (P < 0.001), together with much lower IL-10, as anti-inflammatory cytokine (P < 0.001) compared to controls clearly demonstrated the neurotoxic effects of PPA. Interestingly, the mixture of bee pollen and probiotics was effective in alleviating PPA neurotoxic effects in both therapeutic and protective groups demonstrating highly significant changes in IL-1β, IL-8, IL-10, and IFN-γ levels together with non-significant reduction in IL-6 levels compared to PPA-treated rats. Overall, our findings demonstrated a new approach to the beneficial use of psychobiotics presenting as bee pollen and probiotic combination in neuroinflammation through cytokine changes as a possible role of glial cells in gut–brain axis.

Anti-Inflammatory and Antioxidant in Vitro Activities of Magnoliae Flos Ethanol Extract

This study evaluated Magnoliea Flos ethanol extract (MFE) as a potential natural anti-inflammatory and antioxidant in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and in vitro antioxidant assays. MFE (10, 30, and 50 μg/mL) dose-dependently inhibited LSP-induced nitric oxide production, which is mediated by down-regulating gene and protein expression of inducible nitric oxide synthase and cyclooxygenase-2. MFE also down-regulated both gene and protein expression of nuclear factor-kappa B and its downstream genes, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), compared with vehicle-treated cells. As a result, MFE treatment of LPS-stimulated macrophages significantly suppressed release of pro-inflammatory cytokines, such as TNF-α and IL-6. The antioxidant in vitro test revealed 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities of MFE (0.25∼5 mg/mL) of 16.62% to 75.17% and 38.54% to 92.91%, respectively. The ferric reducing antioxidant ability of MFE was 0.54 mM to 2.14 mM. Overall, MFE exhibited antioxidant activity and an effective anti-inflammatory response in LPS-stimulated macrophages, which is potentially valuable for application as a natural functional material.

Wide-field mosaics of the corneal subbasal nerve plexus in Parkinson's disease using in vivo confocal microscopy

In vivo confocal microscopy (IVCM) is a non-invasive imaging technique facilitating real-time acquisition of images from the live cornea and its layers with high resolution (1-2 µm) and high magnification (600 to 800-fold). IVCM is extensively used to examine the cornea at a cellular level, including the subbasal nerve plexus (SBNP). IVCM of the cornea has thus gained intense interest for probing ophthalmic and systemic diseases affecting peripheral nerves. One of the main drawbacks, however, is the small field of view of IVCM, preventing an overview of SBNP architecture and necessitating subjective image sampling of small areas of the SBNP for analysis. Here, we provide a high-quality dataset of the corneal SBNP reconstructed by automated mosaicking, with an average mosaic image size corresponding to 48 individual IVCM fields of view. The mosaic dataset represents a group of 42 individuals with Parkinson's disease (PD) with and without concurrent restless leg syndrome. Additionally, mosaics from a control group (n = 13) without PD are also provided, along with clinical data for all included participants.

Prevalence of Parkinson's disease in China: a multicenter population-based survey

OBJECTIVE

Few data are available on the current prevalence of Parkinson's disease in China. The aim of this study was to determine the prevalence of Parkinson's disease in Chinese individuals aged 65 years and older and to analyze associated risk factors.

METHODS

We performed a population-based cross-sectional survey with a multistage cluster sampling design. Residents aged 65 and over were drawn from 11 urban districts and 10 rural counties across China. Data were entered into spreadsheets, and imported and analyzed using Statistical Package SPSS 24.

RESULTS

We identified 151 patients with Parkinson's disease among 8124 residents aged 65 and over, including 75 men (49.67%) and 76 women (50.33%). The overall prevalence of PD in the study population was 1.86% (95% confidence interval [CI]: 1.6%-2.2%), and the standardized prevalence of PD was 1.60%. The crude prevalence in men (2.12%) was higher than in women (1.66%), and standardized prevalence in urban areas (1.98%) was higher than in rural areas (1.48%). Logistic regression analysis showed that independent risk factors for PD were older age, heavy metal or pesticide exposure (odds ratio [OR]=3.83; 95% CI: 2.021-7.256), urban residence (OR=1.307; 95% CI: 1.041-1.642), rapid eye movement sleep behavior disorder (OR=1.450; 95% CI: 1.021-2.059), and heart disease (OR=2.431; 95% CI: 1.481-4.990). Conclusion：The prevalence of Parkinson's disease in individuals aged 65 and older in China has not increased significantly in recent years. The prevalence of Parkinson's disease is higher in men than in women and higher in urban areas than in rural areas.

A systematic review of molecular approaches that link mitochondrial dysfunction and neuroinflammation in Parkinson's disease

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder that affects 1% of the population worldwide. Etiology of PD is likely to be multi-factorial such as protein misfolding, mitochondrial dysfunction, oxidative stress, and neuroinflammation that contributes to the pathology of Parkinson's disease (PD), numerous studies have shown that mitochondrial dysfunction may play a key role in the dopaminergic neuronal loss. In multiple ways, the two most important are the activation of neuroinflammation and mitochondrial dysfunction, while mitochondrial dysfunction could cause neuroinflammation and vice versa. Thus, the mitochondrial proteins are the highly promising target for the development of PD. However, the limited amount of dopaminergic neurons prevented the detailed investigation of Parkinson's disease with regard to mitochondrial dysfunction. Both genetic and environmental factors are also associated with mitochondrial dysfunction and PD pathogenesis. The induction of PD by neurotoxins that inhibit mitochondrial complex I provide direct evidence linking mitochondrial dysfunction to PD. A decrease of mitochondrial complex I activity is observed in PD brain and in neurotoxin- or genetic factor-induced in vitro and in vivo models. Moreover, PINK1, Parkin, DJ-1 and LRRK2 mitochondrial PD gene products have important roles in mitophagy, a cellular process that clear damaged mitochondria. This review paper would discuss the evidence for the mitochondrial dysfunction and neuroinflammation in PD.

The role of meningeal populations of type II innate lymphoid cells in modulating neuroinflammation in neurodegenerative diseases

Recent research into meningeal lymphatics has revealed a never-before appreciated role of type II innate lymphoid cells (ILC2s) in modulating neuroinflammation in the central nervous system (CNS). To date, the role of ILC2-mediated inflammation in the periphery has been well studied. However, the exact distribution of ILC2s in the CNS and therefore their putative role in modulating neuroinflammation in neurodegenerative diseases such as Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD), and major depressive disorder (MDD) remain highly elusive. Here, we review the current evidence of ILC2-mediated modulation of neuroinflammatory cues (i.e., IL-33, IL-25, IL-5, IL-13, IL-10, TNFα, and CXCL16-CXCR6) within the CNS, highlight the distribution of ILC2s in both the periphery and CNS, and discuss some challenges associated with cell type-specific targeting that are important for therapeutics. A comprehensive understanding of the roles of ILC2s in mediating and responding to inflammatory cues may provide valuable insight into potential therapeutic strategies for many dementia-related disorders.

Extracellular Vesicles as Novel Diagnostic and Prognostic Biomarkers for Parkinson's Disease

The elderly population will significantly increase in the next decade and, with it, the proportion of people affected by age-related diseases. Among them, one of the most invalidating is Parkinson's disease (PD), characterized by motor- and non-motor dysfunctions which strongly impair the quality of life of affected individuals. PD is characterized by the progressive degeneration of dopaminergic neurons, with consequent dopamine depletion, and the accumulation of misfolded α-synuclein aggregates. Although 150 years have passed since PD first description, no effective therapies are currently available, but only palliative treatments. Importantly, PD is often diagnosed when the neuronal loss is elevated, making difficult any therapeutic intervention. In this context, two key challenges remain unanswered: (i) the early diagnosis to avoid the insurgence of irreversible symptoms; and (ii) the reliable monitoring of therapy efficacy. Research strives to identify novel biomarkers for PD diagnosis, prognosis, and therapeutic follow-up. One of the most promising sources of biomarkers is represented by extracellular vesicles (EVs), a heterogeneous population of nanoparticles, released by all cells in the microenvironment. Brain-derived EVs are able to cross the blood-brain barrier, protecting their payload from enzymatic degradation, and are easily recovered from biofluids. Interestingly, EV content is strongly influenced by the specific pathophysiological status of the donor cell. In this manuscript, the role of EVs as source of novel PD biomarkers is discussed, providing all recent findings concerning relevant proteins and miRNAs carried by PD patient-derived EVs, from several biological specimens. Moreover, the contribution of mitochondria-derived EVs will be dissected. Finally, the promising possibility to use EVs as source of markers to monitor PD therapy efficacy will be also examined. In the future, larger cohort studies will help to validate these EV-associated candidates, that might be effectively used as non-invasive and robust source of biomarkers for PD.