The complex role of inflammation and gliotransmitters in Parkinson's disease

Neuroprotective efficacy of berberine and caffeine against rotenone-induced neuroinflammatory and oxidative disturbances associated with Parkinson's disease via inhibiting α-synuclein aggregation and boosting dopamine release

Parkinson's disease (PD) is characterized by motor impairment, glial-mediated inflammation, redox imbalance, and α-synuclein (α-syn) aggregation. Conventional therapies relieve early PD symptoms, but they do not repair dopaminergic neurons. Berberine (BBR) and caffeine (CAF), both natural alkaloids, exhibited neuroprotective effects in many neurodegenerative disorders. Consequently, we hypothesized that the combination of BBR and CAF therapies would offer protection against PD-related impairments in the rotenone (ROT)-induced rat model when compared to the commercial drug, metformin (MTF). Our results showed that the combined administration of BBR (25 mg/kg/day) and CAF (2.5 mg/kg/day) for four weeks prevented motor deficits, weight reduction, dopamine (DA) depletion, and monoamine oxidase (MAO) activity in ROT-induced rats in comparison with monotherapy of BBR and CAF along with MTF. This combination produced a notable neuroprotective effect by reducing tumor necrosis factor (TNF)-α and interleukin-16 (IL-6) in midbrain of rats. BBR and CAF combinations markedly normalized tyrosine hydroxylase (TH) levels and decreased total α-syn and α-syn-pser129 aggregation and increased protein phosphatase 2A (PP2A) levels. Histological analysis indicated that damaged neurons exhibited significant amelioration with the co-administration of BBR and CAF. The molecular docking results indicated that both BBR and CAF had notable binding affinity for the protein pocket surrounding the α-syn, PP2A, and TH in comparison to MTF. They are predicted to serve as effective inhibitors of enzyme-mediated phosphorylation of α-syn-pser129. Conclusively, combined BBR and CAF administration presents a novel strategy for neuroprotection by blocking the initial events in PD incidence, demonstrating considerable anti-oxidative and anti-inflammatory benefits relative to MTF.

Advancing neurological disorders therapies: Organic nanoparticles as a key to blood-brain barrier penetration

The blood-brain barrier (BBB) plays a vital role in protecting the central nervous system (CNS) by preventing the entry of harmful pathogens from the bloodstream. However, this barrier also presents a significant obstacle when it comes to delivering drugs for the treatment of neurodegenerative diseases and brain cancer. Recent breakthroughs in nanotechnology have paved the way for the creation of a wide range of nanoparticles (NPs) that can serve as carriers for diagnosis and therapy. Regarding their promising properties, organic NPs have the potential to be used as effective carriers for drug delivery across the BBB based on recent advancements. These remarkable NPs have the ability to penetrate the BBB using various mechanisms. This review offers a comprehensive examination of the intricate structure and distinct properties of the BBB, emphasizing its crucial function in preserving brain balance and regulating the transport of ions and molecules. The disruption of the BBB in conditions such as stroke, Alzheimer's disease, and Parkinson's disease highlights the importance of developing creative approaches for delivering drugs. Through the encapsulation of therapeutic molecules and the precise targeting of transport processes in the brain vasculature, organic NP formulations present a hopeful strategy to improve drug transport across the BBB. We explore the changes in properties of the BBB in various pathological conditions and investigate the factors that affect the successful delivery of organic NPs into the brain. In addition, we explore the most promising delivery systems associated with NPs that have shown positive results in treating neurodegenerative and ischemic disorders. This review opens up new possibilities for nanotechnology-based therapies in cerebral diseases.

Scopoletin mitigates maternal separation-induced anxiety-like and depression-like behaviors in male mice through modulation of the Sirt1/NF-κB pathway

RATIONALE

Early-life maternal separation can lead to anxiety-like and depression-like behaviors in mice reared under maternal separation conditions. Scopoletin, a compound with anti-inflammatory and antidepressant properties, may offer therapeutic benefits, but its effectiveness against behaviors induced by maternal separation during adulthood remains unexplored.

OBJECTIVES

This study investigates scopoletin's efficacy in alleviating anxiety-like and depression-like phenotypes in male mice subjected to early-life maternal separation.

METHODS

Male C57BL/6J mice experienced daily maternal separation for 4 h from postnatal day (PND) 2 to 21. From postnatal day 61(PND 61), scopoletin was administered intraperitoneally at 20 mg/kg/day for four weeks. Behavioral and biochemical assessments were conducted at postnatal day 95 (PND 95).

RESULTS

Maternally separated mice displayed marked anxiety-like and depression-like behaviors, evident in behavioral tests like the open field and elevated plus maze. These mice also showed increased immobility in the forced swimming and tail suspension tests. Biochemically, there were elevated levels of IL-1β, IL-6, and TNF-α in the hippocampus, with a decrease in Sirt1 and upregulation in NF-κB p65 expression. Scopoletin treatment significantly mitigated these behavioral abnormalities, normalizing both anxiety-like and depression-like behaviors. Correspondingly, it reduced the levels of pro-inflammatory cytokines and reinstated the expression of Sirt1 and NF-κB p65.

CONCLUSIONS

Scopoletin effectively reverses the adverse behavioral and biochemical effects induced by early-life maternal separation in male mice, suggesting its potential as a therapeutic agent for treating anxiety-like and depression-like behaviors. Modulation of neuroinflammatory pathways and the Sirt1/NF-κB signaling axis is one possible mechanism.

Exploring the Anti-Inflammatory Potential of Ajuga integrifolia Leaves Extract: In Vitro Dual Inhibition of Cyclooxygenase and Lipoxygenase Enzymes

This study investigated the anti-inflammatory properties of Ajuga integrifolia, an herbal preparation. Qualitative and quantitative phytochemical analyses were conducted to identify active compounds in the preparation. The researchers also assessed its ability to inhibit the production of pro-inflammatory enzymes, cyclooxygenases (COX-1, COX-2), and lipoxygenase (5-LOX) in vitro. The extracts demonstrated dose-dependent inhibition of these enzymes, with some extracts showing IC50 values comparable to standard anti-inflammatory drugs. The ethanol extract exhibited significant inhibition of 5-LOX (52.99 μg/mL), compared to the standard drug zileuton (32.41 μg/mL), while the inhibition of COX-1 (66.00 μg/mL) and COX-2 (71.62 μg/mL) was comparable to the standard drug indomethacin (40.57 and 54.39 μg/mL, respectively). These findings suggest that A. integrifolia has the potential to be used as a herbal remedy for treating inflammatory conditions. By inhibiting pro-inflammatory enzymes, the extracts may effectively reduce inflammation and promote tissue healing or repair. The inhibition potential of extract of this plant can be taken as a good candidate of anti-inflammatory agent.

Combating Parkinson's disease with plant-derived polyphenols: Targeting oxidative stress and neuroinflammation

Parkinson's disease (PD) is a devastating neurodegenerative disorder predominantly affecting the elderly, characterized by the loss of dopaminergic neurons in the substantia nigra. Reactive oxygen species (ROS) generation plays a central role in the pathogenesis of PD and other neurodegenerative diseases. An imbalance between cellular antioxidant activity and ROS production leads to oxidative stress, contributing to disease progression. Dopamine metabolism, mitochondrial dysfunction, and neuroinflammation in dopaminergic neurons have been implicated in the pathogenesis of Parkinson's disease. Consequently, there is a pressing need for therapeutic interventions capable of scavenging ROS. Current pharmacological approaches, such as L-dihydroxyphenylalanine (levodopa or L-DOPA) and other drugs, provide symptomatic relief but are limited by severe side effects. Researchers worldwide have been exploring alternative compounds with less toxicity to address the multifaceted challenges associated with Parkinson's disease. In recent years, plant-derived polyphenolic compounds have gained significant attention as potential therapeutic agents. These compounds exhibit neuroprotective effects by targeting pathophysiological responses, including oxidative stress and neuroinflammation, in Parkinson's disease. The objective of this review is to summarize the current understanding of the neuroprotective effects of various polyphenols in Parkinson's disease, focusing on their antioxidant and anti-inflammatory properties, and to discuss their potential as therapeutic candidates. This review highlights the progress made in elucidating the molecular mechanisms of action of these polyphenols, identifying potential therapeutic targets, and optimizing their delivery and bioavailability. Well-designed clinical trials are necessary to establish the efficacy and safety of polyphenol-based interventions in the management of Parkinson's disease.

Moderate intensity aerobic exercise alleviates motor deficits in 6-OHDA lesioned rats and reduces serum levels of biomarkers of Parkinson's disease severity without recovery of striatal dopamine or tyrosine hydroxylase

Alleviation of motor impairment by aerobic exercise (AE) in Parkinson's disease (PD) patients points to activation of neurobiological mechanisms that may be targetable by therapeutic approaches. However, evidence for AE-related recovery of striatal dopamine (DA) signaling or tyrosine hydroxylase (TH) loss has been inconsistent in rodent studies. This ambiguity may be related to the timing of AE intervention in relation to the status of nigrostriatal neuron loss. Here, we replicated human PD at diagnosis by establishing motor impairment with >80% striatal DA and TH loss prior to initiating AE, and assessed its potential to alleviate motor decline and restore DA and TH loss. We also evaluated if serum levels of neurofilament light (NfL) and glial fibrillary acidic protein (GFAP), biomarkers of human PD severity, changed in response to AE. 6-hydroxydopamine (6-OHDA) was infused unilaterally into rat medial forebrain bundle to induce progressive nigrostriatal neuron loss over 28 days. Moderate intensity AE (3× per week, 40 min/session), began 8-10 days post-lesion following establishment of impaired forelimb use. Striatal tissue DA, TH protein and mRNA, and serum levels of NfL/GFAP were determined 3-wks after AE began. Despite severe striatal DA depletion at AE initiation, forelimb use deficits and hypokinesia onset were alleviated by AE, without recovery of striatal DA or TH protein loss, but reduced NfL and GFAP serum levels. This proof-of-concept study shows AE alleviates motor impairment when initiated with >80% striatal DA loss without obligate recovery of striatal DA or TH protein. Moreover, the AE-related reduction of NfL and GFAP serum levels may serve as objective blood-based biomarkers of AE efficacy.

Daytime napping and the incidence of Parkinson's disease: a prospective cohort study with Mendelian randomization

BACKGROUND

The causal relationship between daytime napping and the risk of Parkinson's disease (PD) remains unclear, with prospective studies providing limited evidence. This study investigated the association between daytime napping frequency and duration and PD incidence and explored the causality relationship between this association by conducting Mendelian randomization (MR) analysis.

METHODS

This prospective cohort study included 393,302 participants, and accelerometer-measured daytime napping data were available only for 78,141 individuals. Cox proportional hazards regression was used to estimate the association between the daytime napping frequency and duration and the PD risk. The role of the systemic immune-inflammation index (SII) in the association between daytime napping frequency and PD risk was assessed through mediation analyses. Moreover, the causal association between the daytime napping frequency and the PD risk was preliminarily explored by conducting two-sample MR analyses.

RESULTS

The median follow-up duration was 12.18 years. The participants who reported napping sometimes or usually exhibited a significantly higher PD risk than those who never/rarely napped during the day [sometimes: hazard ratio (HR), 1.13; 95% confidence interval (CI), 1.03-1.23; usually: HR, 1.33; 95% CI, 1.14-1.55], and SII played a mediating role in this association. However, the MR analyses did not indicate that the daytime napping frequency and PD risk were significantly associated. The participants napping for over 1 h exhibited a significantly elevated PD risk (HR, 1.54; 95% CI, 1.11-2.16). Moreover, no significant interaction was identified between napping frequency or duration and genetic susceptibility to PD (P for interaction > 0.05).

CONCLUSIONS

In this study, increased daytime napping frequency and duration were associated with an increased PD risk, but no causal relationship was observed between napping frequency and PD risk in the MR analysis. Larger GWAS-based cohort studies and MR studies are warranted to explore potential causal relationships.

Unveiling the Journey from the Gut to the Brain: Decoding Neurodegeneration-Gut Connection in Parkinson's Disease

Parkinson's disease, a classical motor disorder affecting the dopaminergic system of the brain, has been as a disease of the brain, but this classical notion has now been viewed differently as the pathology begins in the gut and then gradually moves up to the brain regions. The microorganisms in the gut play a critical role in maintaining the physiology of the gut from maintaining barrier integrity to secretion of microbial products that maintain a healthy gut state. The pathology subsequently alters the normal composition of gut microbes and causes deleterious effects that ultimately trigger strong neuroinflammation and nonmotor symptoms along with characteristic synucleopathy, a pathological hallmark of the disease. Understanding the complex pathomechanisms in distinct and established preclinical models is the primary goal of researchers to decipher how exactly gut pathology has a central effect; the quest has led to many answered and some open-ended questions for researchers. We summarize the popular opinions and some contrasting views, concise footsteps in the treatment strategies targeting the gastrointestinal system.

Investigation of the causal association between Parkinson's disease and autoimmune disorders: a bidirectional Mendelian randomization study

Background

To date, an increasing number of epidemiological evidence has pointed to potential relationships between Parkinson's disease (PD) and various autoimmune diseases (AIDs), however, no definitive conclusions has been drawn about whether PD is causally related to AIDs risk.

Methods

By employing summary statistics from the latest and most extensive genome-wide association studies (GWAS), we performed a bidirectional two-sample Mendelian randomization (MR) analysis to investigate the causal associations between PD and a variety of 17 AIDs, encompassing multiple sclerosis, neuromyelitis optica spectrum disorder, myasthenia gravis, asthma, inflammatory bowel disease, Crohn's disease, ulcerative colitis, irritable bowel syndrome, celiac disease, primary biliary cirrhosis, primary sclerosing cholangitis, type 1 diabetes, ankylosing spondylitis, rheumatoid arthritis, systemic lupus erythematosus, psoriasis and vitiligo. Inverse-variance weighted (IVW) was adopted as the main statistical approach to obtain the causal estimates of PD on different AIDs, supplemented by a series of complementary analyses (weighted median, MR Egger regression, and MR-PRESSO) for further strengthening the robustness of results.

Results

Our MR findings suggested that genetically predicted higher liability to PD was causally associated with a decreased risk of irritable bowel syndrome (OR = 0.98; 95% CI: 0.96-0.99; P = 0.032). On the contrary, IVW analysis showed a potential positive correlation between genetically determined PD and the incidence of type 1 diabetes (OR = 1.10; 95%CI: 1.02-1.19; P = 0.010). Subsequent MR tests ended up in similar results, confirming our findings were reliable. Additionally, in the reverse MR analyses, we did not identify any evidence to support the causal relationship of genetic predisposition to AIDs with PD susceptibility.

Conclusion

In general, a bifunctional role that PD exerted on the risk of developing AIDs was detected in our studies, both protecting against irritable bowel syndrome occurrence and raising the incidence of type 1 diabetes. Future studies, including population-based observational studies and molecular experiments in vitro and in vivo, are warranted to validate the results of our MR analyses and refine the underlying pathological mechanisms involved in PD-AIDs associations.

Gastrodia elata polysaccharide alleviates Parkinson's disease via inhibiting apoptotic and inflammatory signaling pathways and modulating the gut microbiota

Parkinson's disease (PD) is a common, chronic, and progressive degenerative disease of the central nervous system for which there is no effective treatment. Gastrodia elata is a well-known food and medicine homologous resource with neuroprotective potential. Gastrodia elata polysaccharide (GEP), which is a highly active and safe component in Gastrodia elata, is an important ingredient in the development of functional products. In this study, GEP was administered to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice over 3 weeks to investigate its neuroprotective effects. The results showed that GEP significantly alleviated the motor dysfunction of PD mice, inhibited the accumulation of α-synuclein, and reduced the loss of dopaminergic neurons in the brain. Moreover, GEP increased the Bcl-2/Bax ratio and decreased the cleaved-caspase-3 level, suggesting that GEP may ameliorate PD by preventing MPTP-induced mitochondrial apoptosis. GEP also significantly inhibited the increase of GFAP and decreased the levels of TNF-α, IL-1β, and IL-6 in the brain of PD mice, which may be the result of the inhibition of neuroinflammation by the inactivation of the TLR4/NF-κB pathway. Furthermore, the neuroprotective effects of GEP involve the gut-brain axis, as it has been shown that GEP regulated the dysbiosis of PD-related gut microbiota such as Akkermansia, Lactobacillus, Bacteroides, Prevotella, and Faecalibacterium, increased the content of microbial metabolites SCFAs in the colon and increased the level of occludin that repairs the intestinal barrier of PD mice. In conclusion, this study is expected to provide a theoretical basis for the development and application of functional products with GEP from the perspective of neuroprotective effects.

Development of a Fluorescently Labeled Ligand for Rapid Detection of DAT in Human and Mouse Peripheral Blood Monocytes

The dopamine transporter (DAT) is one of the key regulators of dopamine (DA) signaling in the central nervous system (CNS) and in the periphery. Recent reports in a model of Parkinson's disease (PD) have shown that dopamine neuronal loss in the CNS impacts the expression of DAT in peripheral immune cells. The mechanism underlying this connection is still unclear but could be illuminated with sensitive and high-throughput detection of DAT-expressing immune cells in the circulation. Herein, we have developed fluorescently labeled ligands (FLL) that bind to surface-expressing DAT with high affinity and selectivity. The diSulfoCy5-FLL (GC04-38) was utilized to label DAT in human and mouse peripheral blood mononuclear cells (PBMCs) that were analyzed via flow cytometry. Selective labeling was validated using DAT KO mouse PBMCs. Our studies provide an efficient and highly sensitive method using this novel DAT-selective FLL to advance our fundamental understanding of DAT expression and activity in PBMCs in health and disease and as a potential peripheral biomarker.

The role of immune and inflammatory-related indicators in cognitive dysfunction and disease severity in patients with parkinson's disease

We aimed to explore the role of immune and inflammatory indicators in cognitive dysfunction and disease severity in patients with Parkinson's disease (PD). A total of 123 patients with Parkinson's disease were enrolled in the PD group and 49 healthy volunteers in the control group. The patients with PD were further divided into 2 subgroups by evaluating cognitive function using the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE): the normal cognitive function (PD-NCI) group and the mild cognitive impairment (PD-MCI) group. Moreover, the PD patients were also divided into 2 subgroups using the defined scale of the Hoehn and Yahr (H-Y) stage: the early-stage group and the middle- and late-stage group. Immune and inflammatory indicators, including serum Aβ1-42, Tau, CD4+, CD8+, CD3+, B lymphocytes cell, NK cell, Th17 cell, Treg cell, IL-6, IL-17, and TNF-α levels, were evaluated and analyzed to explore the potential correlation with the cognitive dysfunction and disease severity of PD. Among the 123 PD patients, 60 (48.8%) were diagnosed with mild cognitive impairment. Aβ1-42, CD4+, CD8+, CD3+, and Treg levels observed in the PD-NCI group were lower than the control group (P < 0.001), while higher than the PD-MCI group (P < 0.001). The levels of Tau, Th17, IL-6, IL-17, and TNF-α observed in the PD-NCI group were higher than the control group (P < 0.001), while lower than in the PD-MCI group (P < 0.01). Using the same method, the results of the early-stage group and the middle- and the late-stage group were the same as above. Logistic regression analysis and ROC curve estimation were performed and indicated that the variation of Tau, CD8+, Treg, TNF-α levels was associated with cognitive decline in PD patients, and may serve as markers of PD onset. Furthermore, the variation of Aβ1-42, IL-6, and TNF-α levels was found to correlate with the disease severity of PD. The immune and inflammatory-related indicators may represent an important factor in the pathogenesis of PD, cognitive dysfunction, and disease severity. The variation of Tau protein, CD8+, Treg, and TNF-α levels are associated with the cognitive dysfunction of PD, which may be considered as onset markers. Moreover, the variation of Aβ1-42, IL-6, and TNF-α levels can predict the progression of PD.

[Preparation of sulfonic acid functionalized covalent organic framework solid phase microextraction fibers and their application in the analysis of neurotransmitters in the mouse brain]

Neurotransmitters (NTs) are essential for intercellular communication and primarily include monoamine, amino acid, and cholinergic NTs. These molecules play important roles in the body's stress response, motor coordination, neuronal communication, and homeostatic functions. Previous studies have shown that abnormal changes in NT levels are associated with various neurological disorders. Therefore, the development of accurate analytical methods for NT detection will enhance the current understanding on complex neuropathophysiology by providing functional knowledge and techniques for early diagnosis, thereby facilitating the development of new therapeutic options for the related diseases. The solid phase microextraction (SPME) technique combines sample preparation, separation, and enrichment in a single step and is minimally invasive, low cost, solvent free, and high throughput. SPME has been successfully applied to the in vivo analysis of target analytes in animal, human, and plant tissues. The coating material plays a significant role in the development of in vivo SPME methods and must meet various analytical requirements, including a suitable geometry for the SPME device, high extraction capacity, excellent selectivity, and wide extraction coverage for the target analytes. Covalent organic frameworks (COFs) are porous crystalline polymers constructed from organic framework units through strong covalent bonds; these materials are characterized with a low density, large specific surface area, permanent porosity, excellent chemical/thermal stability, and easy functionalization.In this study, a sulfonic acid-functionalized COF material (COF-SO3H) with good crystallinity, excellent chemical/thermal stability, strong hydrophobicity, a uniform mesoporous structure, and narrow pore size distribution was prepared using 2,4,6-triformylphloroglucinol and 1,4-diamino-2-nitrobenzene as monomers. Then, the COF-SO3H was coated onto the surface of stainless-steel fibers and used for in vivo enrichment of NTs. The structural properties of COF-SO3H were characterized using various techniques, such as scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), all of which showed that COF-SO3H had a good crystalline structure and uniform mesopore distribution with a specific surface area of 46.17 m2/g. Compared with the SPME fibers of HLB, C18, MCX, amino, and PXC columns, the prepared COF-SO3H fibers showed better extraction efficiency for the target NTs. Next, the factors affecting SPME efficiency were optimized. The optimal desorption solvent was formic acid-methanol-water (0.5∶49.5∶50, v/v/v), and the optimal extraction and desorption times were 15 min. A method for the in vivo analysis of NTs in the brains of mice was established by combining the COF-SO3H fibers with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) under optimal conditions. The NTs were separated on an Acquity UPLC BEH-C18 analytical column (100 mm×2.1 mm, 1.7 μm) with 0.1% formic acid aqueous solution (A) and acetonitrile (B) as the mobile phases. The flow rate was set to 0.2 mL/min, and the gradient elution procedure was as follows: 0-4 min, 5%B-6%B; 4-7 min, 6%B-5%B; 7-11 min, 5%B. Under optimal conditions, the method showed good linearity (r2>0.99). The limits of quantification (S/N≥5) were in the range of 0.003-0.005 μg/mL and 3-5 μg/mL for monoamine and amino acid NTs, respectively, with RSDs of less than 20%. The method showed good precision (0.80%-9.70%) and accuracy (2.08%-17.72%), with absolute matrix effects in the range of 82.22%-117.92%. These values reflect the good purification and enrichment abilities of the proposed fibers for the target analytes. Finally, the established SPME method was combined with UPLC-MS/MS and successfully applied to quantify target NTs in the brains of mice. The proposed strategy provides a practical method for the in vivo detection and quantitative analysis of NTs and expands the applications of functionalized COF materials for the analysis of various targets.

Parkinson's Disease and the Heart: Studying Cardiac Metabolism in the 6-Hydroxydopamine Model

Parkinson's-disease (PD) is an incurable, age-related neurodegenerative disease, and its global prevalence of disability and death has increased exponentially. Although motor symptoms are the characteristic manifestations of PD, the clinical spectrum also contains a wide variety of non-motor symptoms, which are the main cause of disability and determinants of the decrease in a patient's quality of life. Noteworthy in this regard is the stress on the cardiac system that is often observed in the course of PD; however, its effects have not yet been adequately researched. Here, an untargeted metabolomics approach was used to assess changes in cardiac metabolism in the 6-hydroxydopamine model of PD. Beta-sitosterol, campesterol, cholesterol, monoacylglycerol, α-tocopherol, stearic acid, beta-glycerophosphoric acid, o-phosphoethanolamine, myo-inositol-1-phosphate, alanine, valine and allothreonine are the metabolites that significantly discriminate parkinsonian rats from sham counterparts. Upon analysis of the metabolic pathways with the aim of uncovering the main biological pathways involved in concentration patterns of cardiac metabolites, the biosynthesis of both phosphatidylethanolamine and phosphatidylcholine, the glucose-alanine cycle, glutathione metabolism and plasmalogen synthesis most adequately differentiated sham and parkinsonian rats. Our results reveal that both lipid and energy metabolism are particularly involved in changes in cardiac metabolism in PD. These results provide insight into cardiac metabolic signatures in PD and indicate potential targets for further investigation.

Nervonic acid improves liver inflammation in a mouse model of Parkinson's disease by inhibiting proinflammatory signaling pathways and regulating metabolic pathways

BACKGROUND

Nervonic acid (NA) - a type of bioactive fatty acid that is found in natural sources - can inhibit inflammatory reactions and regulate immune system balance. Therefore, the use of NA for the treatment of neurodegenerative diseases has received considerable attention. Our previous study found that NA inhibited inflammatory responses in the brain of Parkinson's disease (PD) mouse models. In addition to the brain, PD is also associated with visceral organ dysfunction, especially impaired liver function. Thus, studying the role of NA in PD-mediated inflammation of the liver is particularly important.

METHODS

A combined transcriptome and metabolomic approach was utilized to investigate the anti-inflammatory effects of NA on the liver of PD mice. Inflammatory signaling molecules and metabolic pathway-related genes were examined in the liver using real-time PCR and western blotting.

RESULTS

Liver transcriptome analysis revealed that NA exerted anti-inflammatory effects by controlling several pro-inflammatory signaling pathways, such as the down-regulation of the tumor necrosis factor and nuclear factor kappa B signaling pathways, both of which were essential in the development of inflammatory disease. In addition, liver metabolomic results revealed that metabolites related to steroid hormone biosynthesis, arachidonic acid metabolism, and linoleic acid metabolism were up-regulated and those related to valine, leucine, and isoleucine degradation pathways were down-regulated in NA treatment groups compared with the PD model. The integration of metabolomic and transcriptomic results showed NA significantly exerted its anti-inflammatory function by regulating the transcription and metabolic pathways of multiple genes. Particularly, linoleic acid metabolism, arachidonic acid metabolism, and steroid hormone biosynthesis were the crucial pathways of the anti-inflammatory action of NA. Key genes in these metabolic pathways and key molecules in inflammatory signaling pathways were also verified, which were consistent with transcriptomic results.

CONCLUSION

These findings provide novel insights into the liver protective effects of NA against PD mice. This study also showed that NA could be a useful dietary element for improving and treating PD-induced liver inflammation.

Effect and mechanism of chlorogenic acid on cognitive dysfunction in mice by lipopolysaccharide-induced neuroinflammation

Background

Neuroinflammation is an important factor causing numerous neurodegenerative pathologies. Inflammation can lead to abnormal neuronal structure and function and even death, followed by cognitive dysfunction. There is growing evidence that chlorogenic acid has anti-inflammatory effects and immunomodulatory activity.

Purpose

The aim of this study was to elucidate the potential targets and molecular mechanisms of chlorogenic acid in the treatment of neuroinflammation.

Methods

We used the lipopolysaccharide-induced neuroinflammation mouse model and the lipopolysaccharide-stimulated BV-2 cells in vitro model. Behavioral scores and experiments were used to assess cognitive dysfunction in mice. HE staining and immunohistochemistry were used to assess neuronal damage in the mouse brain. Immunofluorescence detected microglia polarization in mouse brain. Western blot and flow cytometry detected the polarization of BV-2 cells. The migration of BV-2 cells was detected by wound healing assay and transwell assay. Potential targets for chlorogenic acid to exert protective effects were predicted by network pharmacology. These targets were then validated using molecular docking and experiments.

Results

The results of in vivo experiments showed that chlorogenic acid had an obvious ameliorating effect on neuroinflammation-induced cognitive dysfunction. We found that chlorogenic acid was able to inhibit BV-2 cells M1 polarization and promote BV-2 cells M2 polarization in vitro while also inhibiting the abnormal migration of BV-2 cells. Based on the network pharmacology results, we identified the TNF signaling pathway as a key signaling pathway in which chlorogenic acid exerts anti-neuroinflammatory effects. Among them, Akt1, TNF, MMP9, PTGS2, MAPK1, MAPK14, and RELA are the core targets for chlorogenic acid to function.

Conclusion

Chlorogenic acid can inhibit microglial polarization toward the M1 phenotype and improve neuroinflammation-induced cognitive dysfunction in mice by modulating these key targets in the TNF signaling pathway.

Resveratrol ameliorates maternal separation-induced anxiety- and depression-like behaviors and reduces Sirt1-NF-kB signaling-mediated neuroinflammation

Maternal separation in early life has a detrimental effect on the physiological and biochemical functions of the brains of offspring and can lead to anxiety- and depression-like behaviors later in life. Resveratrol possesses a variety of pharmacological properties, including anti-inflammatory, anxiolytic, and anti-depressive effects. In rodents, resveratrol can attenuate anxiety- and depression-like behaviors induced by chronic unpredictable mild stress, estrogen deficiency, and lipopolysaccharide. However, whether resveratrol administration during adolescence can counteract these behaviors when they result from maternal separation is unknown. In this study, male C57BL/6J mice were separated from their mothers for 4 h per day from postnatal day 2 (PND 2) to PND 21; starting on PND 61, resveratrol was administered intraperitoneally at 40 mg/(kg/day^-1) for 4 weeks. At 3 months of age, anxiety and depression-like behaviors were assessed in the male offspring using a series of tasks consisting of an open field test, an elevated plus maze test, a forced swimming test, and a tail suspension test. The hippocampal levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) were measured by ELISA, while those of sirtuin 1 (Sirt1) and nuclear factor kappa B (NF-κB) p65 were determined by western blotting and PCR. The results showed that maternal separation led to increased anxiety- and depression-like behaviors, enhanced the levels of pro-inflammatory cytokines, and downregulated the Sirt1/NF-κB signaling pathway in the male offspring; however, these effects could be reversed by treatment with resveratrol. Our findings suggested that resveratrol can ameliorate inflammation and anxiety- and depression-like behaviors induced by maternal separation via the activation of the Sirt1/NF-κB pathway.

Impact of Sex on Neuroimmune contributions to Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. Inflammation has been observed in both the idiopathic and familial forms of PD. Importantly, PD is reported more often in men than in women, men having at least 1.5- fold higher risk to develop PD than women. This review summarizes the impact of biological sex and sex hormones on the neuroimmune contributions to PD and its investigation in animal models of PD. Innate and peripheral immune systems participate in the brain neuroinflammation of PD patients and is reproduced in neurotoxin, genetic and alpha-synuclein based models of PD. Microglia and astrocytes are the main cells of the innate immune system in the central nervous system and are the first to react to restore homeostasis in the brain. Analysis of serum immunoprofiles in female and male control and PD patients show that a great proportion of these markers differ between male and female. The relationship between CSF inflammatory markers and PD clinical characteristics or PD biomarkers shows sex differences. Conversely, in animal models of PD, sex differences in inflammation are well documented and the beneficial effects of endogenous and exogenous estrogenic modulation in inflammation have been reported. Targeting neuroinflammation in PD is an emerging therapeutic option but gonadal drugs have not yet been investigated in this respect, thus offering new opportunities for sex specific treatments.