Oxymatrine Attenuates Dopaminergic Neuronal Damage and Microglia-Mediated Neuroinflammation Through Cathepsin D-Dependent HMGB1/TLR4/NF-κB Pathway in Parkinson's Disease

Mechanistic insights on TLR-4 mediated inflammatory pathway in neurodegenerative diseases

Neurodegenerative diseases (NDDs) pose a significant issue in healthcare, needing a thorough knowledge of their complex molecular mechanisms. A diverse set of cell signaling mediators and their interactions play critical roles in neuroinflammation. The release of pro-inflammatory mediators in response to neural dysfunction is detrimental to normal cell survival. Moreover, the important role of nuclear factor-κB (NF-κB) in the central nervous system through Toll-like receptor (TLR) activation has been well established. Therefore, through a comprehensive review of current research and experimentation, this investigation elucidates the interactions between novel pharmacological agents (TLR-4/NF-κB inhibitors) and neurodegeneration encompassing Alzheimer's, Parkinson's, Huntington's disease, amyotrophic lateral sclerosis and stroke. Insights garnered from this exploration underscore the potential of TLR-4 as a therapeutic target. Through the revelation of these insights, our aim is to establish a foundation for the development of enhanced and focused therapeutic approaches in the continuous endeavor to combat neurodegeneration. This review thus serves as a roadmap, guiding future research endeavors toward innovative strategies for combatting the complex interplay between TLR-4 signaling and NDDs.

Antimicrobial drugs for Parkinson's disease: Existing therapeutic strategies and novel drugs exploration

Parkinson's disease (PD), the second most common neurodegenerative disorder, is characterized by loss of dopaminergic neurons in the substantia nigra, as well as the abnormal accumulation of misfolded α-synuclein. Clinically, PD is featured by typical motor symptoms and some non-motor symptoms. Up to now, although considerable progress has been made in understanding the pathogenesis of PD, there is still no effective therapeutic treatment for the disease. Thus, exploring new therapeutic strategies has been a topic that needs to be addressed urgently. Noteworthy, with the proposal of the microbiota-gut-brain axis theory, antimicrobial drugs have received significant attention due to their effects on regulating the intestinal microbiota. Nowadays, there is growing evidence showing that some antimicrobial drugs may be promising drugs for the treatment of PD. Data from pre-clinical and clinical studies have shown that some antimicrobial drugs may play neuroprotective roles in PD by modulating multiple biochemical and molecular pathways, including reducing α-synuclein aggregation, inhibiting neuroinflammation, regulating mitochondrial structure and function, as well as suppressing oxidative stress. In this paper, we summarized the effects of some antimicrobial drugs on PD treatment from recent pre-clinical and clinical studies. Then, we further discussed the potential of a few antimicrobial drugs for treating PD based on molecular docking and molecular dynamics simulation. Importantly, we highlighted the potential of clorobiocin as the therapeutic strategy for PD owing to its ability to inhibit α-synuclein aggregation. These results will help us to better understand the potential of antimicrobial drugs in treating PD and how antimicrobial drugs may alleviate or reverse the pathological symptoms of PD.

HMGB1 Mediates Inflammation-Induced DMT1 Increase and Dopaminergic Neurodegeneration in the Early Stage of Parkinsonism

Both neuroinflammation and iron accumulation play roles in the pathogenesis of Parkinson's disease (PD). However, whether inflammation induces iron dyshomeostasis in dopaminergic neurons at an early stage of PD, at which no quantifiable dopaminergic neuron loss can be observed, is still unknown. As for the inflammation mediators, although several cytokines have been reported to increase in PD, the functions of these cytokines in the SN are double-edged and controversial. In this study, whether inflammation could induce iron dyshomeostasis in dopaminergic neurons through high mobility group protein B1 (HMGB1) in the early stage of PD is explored. Lipopolysaccharide (LPS), a toxin that primarily activates glia cells, and 6-hydroxydopamine (6-OHDA), the neurotoxin that firstly impacts dopaminergic neurons, were utilized to mimic PD in rats. We found a common and exceedingly early over-production of HMGB1, followed by an increase of divalent metal transporter 1 with iron responsive element (DMT1+) in the dopaminergic neurons before quantifiable neuronal loss. HMGB1 neutralizing antibody suppressed inflammation in the SN, DMT1+ elevation in dopaminergic neurons, and dopaminergic neuronal loss in both LPS and 6-OHDA administration- induced PD models. On the contrary, interleukin-1β inhibitor diacerein failed to suppress these outcomes induced by 6-OHDA. Our findings not only demonstrate that inflammation could be one of the causes of DMT1+ increase in dopaminergic neurons, but also highlight HMGB1 as a pivotal early mediator of inflammation-induced iron increase and subsequent neurodegeneration, thereby HMGB1 could serve as a potential target for early-stage PD treatment.

Sophora flavescens-Angelica sinensis in the treatment of eczema by inhibiting TLR4/MyD88/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Sophora flavescens Ait.-Angelica sinensis(Oliv.) Diels drug pairing (SA) is a transformed drug pairing from Shengui pill, a traditional Chinese medicine prescription in the ninth volume of Traditional Chinese Medicine classic "Gu Jin Yi Jian", which is famous for clearing heat, moistening dryness, and promoting blood circulation. It is commonly used in the treatment of eczema, a skin condition that causes itching and inflammation. Despite its widespread use, there is still limited research on the mechanism of how SA treats eczema. This paper aims to fill this gap by conducting animal experiments to uncover the mechanism behind SA's therapeutic effects on eczema. Our findings provide a solid foundation for the clinical use of this TCM prescription.

AIM OF THE STUDY

The basic purpose of this study is to clarify the therapeutic mechanism of Sophora flavescens-Angelica sinensis (SA) in the treatment and control of eczema.

MATERIALS AND METHODS

The chemical compositions of SA were analyzed using HPLC-Q-Orbitrap-MS. In vivo, a mouse model of eczema was created, and the serum levels of TNF-α and IL-1β were quantified using an enzyme-linked immunosorbent assay (ELISA). Hematoxylin and eosin (HE) staining was performed to assess the pathological state of the mouse skin, and immunohistochemical technique (IHC) was employed to estimate the contents of TNF-α, TLR4, and NF-κB semi-quantitatively. The expression levels of TLR4, MyD88, and NF-κB mRNA were determined through real-time quantitative polymerase chain reaction (qRT-PCR). Western Blotting was utilized to identify the protein levels of TLR4, MyD88, and NF-κB in mouse skin tissue.

RESULTS

SA identified 18 active chemicals, some of which were shown in vivo to inhibit the TLR4/MyD88/NF-κB signaling pathway while reducing serum levels of TNF-α and IL-1β, making them ideal agents for the treatment of eczema.

CONCLUSIONS

SA's anti-inflammatory properties are attributed to its ability to reduce serum levels of TNF-α and IL-1β, likewise inhibit the TLR4/MyD88/NF-κB signaling pathway.

High Mobility Group Box 1 Protein: A Plausible Therapeutic Molecular Target in Parkinson's Disease

Parkinson's disease (PD) is a widespread neurodegenerative disorder that exerts a broad variety of detrimental effects on people's health. Accumulating evidence suggests that mitochondrial dysfunction, neuroinflammation, α-synuclein aggregation and autophagy dysfunction may all play a role in the development of PD. However, the molecular mechanisms behind these pathophysiological processes remain unknown. Currently, research in PD has focussed on high mobility group box 1 (HMGB1), and different laboratory approaches have shown promising outcomes to some level for blocking HMGB1. Given that HMGB1 regulates mitochondrial dysfunction, participates in neuroinflammation, and modulates autophagy and apoptosis, it is hypothesised that HMGB1 has significance in the onset of PD. In the current review, research targeting multiple roles of HMGB1 in PD pathology was integrated, and the issues that need future attention for targeted therapeutic approaches are mentioned.

Protective effects of dioscin against Parkinson's disease via regulating bile acid metabolism through remodeling gut microbiome/GLP-1 signaling

It is necessary to explore potent therapeutic agents via regulating gut microbiota and metabolism to combat Parkinson's disease (PD). Dioscin, a bioactive steroidal saponin, shows various activities. However, its effects and mechanisms against PD are limited. In this study, dioscin dramatically alleviated neuroinflammation and oxidative stress, and restored the disorders of mice induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). 16 S rDNA sequencing assay demonstrated that dioscin reversed MPTP-induced gut dysbiosis to decrease Firmicutes-to-Bacteroidetes ratio and the abundances of Enterococcus, Streptococcus, Bacteroides and Lactobacillus genera, which further inhibited bile salt hydrolase (BSH) activity and blocked bile acid (BA) deconjugation. Fecal microbiome transplantation test showed that the anti-PD effect of dioscin was gut microbiota-dependent. In addition, non-targeted fecal metabolomics assays revealed many differential metabolites in adjusting steroid biosynthesis and primary bile acid biosynthesis. Moreover, targeted bile acid metabolomics assay indicated that dioscin increased the levels of ursodeoxycholic acid, tauroursodeoxycholic acid, taurodeoxycholic acid and β-muricholic acid in feces and serum. In addition, ursodeoxycholic acid administration markedly improved the protective effects of dioscin against PD in mice. Mechanistic test indicated that dioscin significantly up-regulated the levels of takeda G protein-coupled receptor 5 (TGR5), glucagon-like peptide-1 receptor (GLP-1R), GLP-1, superoxide dismutase (SOD), and down-regulated NADPH oxidases 2 (NOX2) and nuclear factor-kappaB (NF-κB) levels. Our data indicated that dioscin ameliorated PD phenotype by restoring gut dysbiosis and regulating bile acid-mediated oxidative stress and neuroinflammation via targeting GLP-1 signal in MPTP-induced PD mice, suggesting that the compound should be considered as a prebiotic agent to treat PD in the future.

Strontium Attenuates Hippocampal Damage via Suppressing Neuroinflammation in High-Fat Diet-Induced NAFLD Mice

Non-alcoholic fatty liver disease (NAFLD) leads to hippocampal damage and causes a variety of physiopathological responses, including the induction of endoplasmic reticulum stress (ERS), neuroinflammation, and alterations in synaptic plasticity. As an important trace element, strontium (Sr) has been reported to have antioxidant effects, to have anti-inflammatory effects, and to cause the inhibition of adipogenesis. The present study was undertaken to investigate the protective effects of Sr on hippocampal damage in NAFLD mice in order to elucidate the underlying mechanism of Sr in NAFLD. The mouse model of NAFLD was established by feeding mice a high-fat diet (HFD), and the mice were treated with Sr. In the NAFLD mice, we found that treatment with Sr significantly increased the density of c-Fos⁺ cells in the hippocampus and inhibited the expression of caspase-3 by suppressing ERS. Surprisingly, the induction of neuroinflammation and the increased expression of inflammatory cytokines in the hippocampus following an HFD were attenuated by Sr treatment. Sr significantly attenuated the activation of microglia and astrocytes induced by an HFD. The expression of phospho-p38, ERK, and NF-κB was consistently significantly increased in the HFD group, and treatment with Sr decreased their expression. Moreover, Sr prevented HFD-induced damage to the ultra-structural synaptic architecture. This study implies that Sr has beneficial effects on repairing the damage to the hippocampus induced by an HFD, revealing that Sr could be a potential candidate for protection from neural damage caused by NAFLD.

The role of high mobility group box 1 in neuroinflammatory related diseases

High mobility group box 1 (HMGB1) is a ubiquitous and highly conserved non-histone DNA-binding protein with different biological functions according to its subcellular localization. It is widely believed that HMGB1, which is released into the extracellular space, plays a key role in the inflammatory response. In recent years, numerous studies have shown that the development of various neurological diseases such as epilepsy, Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), cerebrovascular disease and traumatic brain injury (TBI) are inextricably linked to inflammation. We will review the mechanisms of HMGB1 and its receptors in nervous system inflammation to provide a basis for further development of new HMGB1-based therapies.

Suppression of neuroinflammation and α-synuclein oligomerization by rotarod walking exercise in subacute MPTP model of Parkinson's disease

Parkinson's disease (PD) belongs to an α-synucleinopathy and manifests motor dysfunction attributed to nigrostriatal dopaminergic degeneration. In clinical practice, the beneficial role of physical therapy such as motor skill learning training has been recognized in PD-linked motor defects. Nevertheless, the disease-modifying effects of motor skill learning training on PD-related pathology remain unclear. Here, we investigated the disease-modifying effects of rotarod walking exercise (RWE), a modality of motor skill learning training, in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. In motor function and dopaminergic degeneration, RWE improved MPTP-induced deficits. In addition, RWE enhanced the expression of neurotrophic factors BDNF/GDNF, PGC1-α, Nurr1, and p-AMPK, thereby recovering dopaminergic neuronal cell death. Moreover, RWE inhibited microglial activation and the expression of pro-inflammatory markers, such as p-IκBα, iNOS, IL-1β, TNF-α, and cathepsin D, while elevating anti-inflammatory IL-10 and TGF-β. RWE also decreased oxidative stress markers in the substantia nigra, such as 4-HNE and 8-OHdG-positive cells, while increasing Nrf2-controlled antioxidant enzymes. Regarding the effect of RWE on α-synuclein, it reduced the monomer/oligomer forms of α-synuclein and phosphorylation at serine 129. Further mechanistic studies revealed that RWE suppressed the expression of matrix metalloproteinase-3 and p-GSK3β (Y216), which play key roles in α-synuclein aggregation. These data collectively suggest that inhibition of neuroinflammation and α-synuclein oligomerization by RWE may contribute to the improvement of PD pathology.

Dual roles of anesthetics in postoperative cognitive dysfunction: Regulation of microglial activation through inflammatory signaling pathways

Postoperative cognitive dysfunction (POCD) is a prevalent clinical entity following surgery and is characterized by declined neurocognitive function. Neuroinflammation mediated by microglia is the essential mechanism of POCD. Anesthetics are thought to be a major contributor to the development of POCD, as they promote microglial activation and induce neuroinflammation. However, this claim remains controversial. Anesthetics can exert both anti- and pro-inflammatory effects by modulating microglial activation, suggesting that anesthetics may play dual roles in the pathogenesis of POCD. Here, we review the mechanisms by which the commonly used anesthetics regulate microglial activation via inflammatory signaling pathways, showing both anti- and pro-inflammatory properties of anesthetics, and indicating how perioperative administration of anesthetics might either relieve or worsen POCD development. The potential for anesthetics to enhance cognitive performance based on their anti-inflammatory properties is further discussed, emphasizing that the beneficial effects of anesthetics vary depending on dose, exposure time, and patients' characteristics. To minimize the incidence of POCD, we recommend considering these factors to select appropriate anesthetics.

Role of traditional Chinese medicine in ameliorating mitochondrial dysfunction via non-coding RNA signaling: Implication in the treatment of neurodegenerative diseases

Neurodegenerative diseases (NDs) are common chronic disorders associated with progressive nervous system damage, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, among others. Mitochondria are abundant in various nervous system cells and provide a bulk supply of the adenosine triphosphate necessary for brain function, considered the center of the free-radical theory of aging. One common feature of NDs is mitochondrial dysfunction, which is involved in many physiopathological processes, including apoptosis, inflammation, oxidative stress, and calcium homeostasis. Recently, genetic studies revealed extensive links between mitochondrion impairment and dysregulation of non-coding RNAs (ncRNAs) in the pathology of NDs. Traditional Chinese medicines (TCMs) have been used for thousands of years in treating NDs. Numerous modern pharmacological studies have demonstrated the therapeutic effects of prescription, herbal medicine, bioactive ingredients, and monomer compounds of TCMs, which are important for managing the symptoms of NDs. Some highly effective TCMs exert protective effects on various key pathological features regulated by mitochondria and play a pivotal role in recovering disrupted signaling pathways. These disrupted signaling pathways are induced by abnormally-expressed ncRNAs associated with mitochondrial dysfunction, including microRNAs, long ncRNAs, and circular RNAs. In this review, we first explored the underlying ncRNA mechanisms linking mitochondrial dysfunction and neurodegeneration, demonstrating the implication of ncRNA-induced mitochondrial dysfunction in the pathogenesis of NDs. The ncRNA-induced mitochondrial dysfunctions affect mitochondrial biogenesis, dynamics, autophagy, Ca²⁺ homeostasis, oxidative stress, and downstream apoptosis. The review also discussed the targeting of the disease-related mitochondrial proteins in NDs and the protective effects of TCM formulas with definite composition, standardized extracts from individual TCMs, and monomeric compounds isolated from TCM. Additionally, we explored the ncRNA regulation of mitochondrial dysfunction in NDs and the effects and potential mechanisms of representative TCMs in alleviating mitochondrial pathogenesis and conferring anti-inflammatory, antioxidant, and anti-apoptotic pathways against NDs. Therefore, this review presents an overview of the role of mitochondrion-related ncRNAs and the target genes for TCM-based therapeutic interventions in NDs, providing insight into understanding the "multi-level compound-target-pathway regulatory" treatment mechanism of TCMs.

Phytochemicals targeting nitric oxide signaling in neurodegenerative diseases

Neurodegenerative diseases are a set of diseases in which slow and progressive neuronal loss occurs. Nitric oxide (NO) as a neurotransmitter performs key roles in the stimulation and blockade of various inflammatory processes. Although physiological NO is necessary for protection against a variety of pathogens, reactive oxygen species-mediated oxidative stress induces inflammatory cascades and apoptosis. Activation of glial cells particularly astrocytes and microglia induce overproduction of NO, resulting in neuroinflammation and neurodegenerative disorders. Hence, inhibiting the overproduction of NO is a beneficial therapeutic approach for numerous neuroinflammatory conditions. Several compounds have been explored for the management of neurodegenerative disorders, but they have minor symptomatic benefits and several adverse effects. Phytochemicals have currently gained more consideration owing to their ability to reduce the overproduction of NO in neurodegenerative disorders. Furthermore, phytochemicals are generally considered to be safe and beneficial. The mechanisms of NO generation and their implications in neurodegenerative disorders are explored in this review article, as well as several newly discovered phytochemicals that might have NO inhibitory activity. The current review could aid in the discovery of new anti-neuroinflammatory drugs that can suppress NO generation, particularly during neuroinflammatory and neurodegenerative conditions.

Protective Effects of Sophorae tonkinensis Gagnep. (Fabaceae) Radix et Rhizoma Water Extract on Carbon Tetrachloride-Induced Acute Liver Injury

Sophorae tonkinensis Radix et Rhizoma (STR) is a traditional Chinese herbal medicine. STR can reduce aminotransferase activity; however, the specific mechanism remains unclear. Here, we explored the potential therapeutic effects and hepatoprotective mechanism of STR on liver damage in mice. The chemical characteristics of the extract were characterized using ultra-high-performance liquid chromatography-tandem mass spectrometry fingerprinting, and its antioxidant capacity was verified using free radical scavenging tests. Forty-eight Kunming mice were randomly assigned into six groups. The model was made after the corresponding drug was given. The results showed that the STR water extract pretreatment significantly reduced serum aminotransferase and related liver function indicators compared with that in the model group. Furthermore, the STR water extract pretreatment significantly inhibited the apoptosis of liver cells, the level of liver high-mobility group box 1 (HMGB1), and inflammatory factors in hepatic tissue compared with that in the model group, and significantly downregulated the levels of toll-like receptor 4 (TLR4), Myeloid differentiation factor 88 (MyD88), and nuclear factor kappa B (NF-κB) compared with those in the model group. Overall, the STR water extract exerted a significant protective effect on CCL₄-induced acute liver injury in this study, and the accurate active ingredients of the STR water extract will be explored in the near future.

HMGB1 in nervous system diseases: A common biomarker and potential therapeutic target

High-mobility group box-1 (HMGB1) is a nuclear protein associated with early inflammatory changes upon extracellular secretion expressed in various cells, including neurons and microglia. With the progress of research, neuroinflammation is believed to be involved in the pathogenesis of neurological diseases such as Parkinson's, epilepsy, and autism. As a key promoter of neuroinflammation, HMGB1 is thought to be involved in the pathogenesis of Parkinson's disease, stroke, traumatic brain injury, epilepsy, autism, depression, multiple sclerosis, and amyotrophic lateral sclerosis. However, in the clinic, HMGB1 has not been described as a biomarker for the above-mentioned diseases. However, the current preclinical research results show that HMGB1 antagonists have positive significance in the treatment of Parkinson's disease, stroke, traumatic brain injury, epilepsy, and other diseases. This review discusses the possible mechanisms by which HMGB1 mediates Parkinson's disease, stroke, traumatic brain injury, epilepsy, autism, depression, multiple sclerosis, amyotrophic lateral sclerosis, and the potential of HMGB1 as a biomarker for these diseases. Future research needs to further explore the underlying molecular mechanisms and clinical translation.

The Role of High Mobility Group Box 1 (HMGB1) in Neurodegeneration: A Systematic Review

BACKGROUND

High mobility group box 1 (HMGB1) protein is a damage-associated molecular pattern (DAMP) that plays an important role in the repair and regeneration of tissue injury. It also acts as a pro-inflammatory cytokine through the activation of toll-like receptor 4 (TLR4) and receptor for advanced glycation end products (RAGE), to elicit the neuroinflammatory response. HMGB1 may aggravate several cellular responses, which may lead to pathological inflammation and cellular death. Thus, there have been a considerable amount of research into the pathological role of HMGB1 in diseases. However, whether the mechanism of action of HMGB1 is similar in all neurodegenerative disease pathology remains to be determined.

OBJECTIVE

Therefore, this systematic review aimed to critically evaluate and elucidate the role of HMGB1 in the pathology of neurodegeneration based on the available literature.

METHODS

A comprehensive literature search was performed on four databases; EMBASE, PubMed, Scopus, and CINAHL Plus.

RESULTS

A total of 85 articles were selected for critical appraisal, after subjecting to the inclusion and exclusion criteria in this study. The selected articles revealed that HMGB1 levels were found elevated in most neurodegeneration except in Huntington's disease and Spinocerebellar ataxia, where the levels were found decreased. This review also showcased that HMGB1 may act on distinctive pathways to elicit its pathological response leading to the various neurodegeneration processes/ diseases.

CONCLUSION

While there have been promising findings in HMGB1 intervention research, further studies may still be required before any HMGB1 intervention may be recommended as a therapeutic target for neurodegenerative diseases.

HMGB1-NLRP3-P2X7R pathway participates in PM2.5-induced hippocampal neuron impairment by regulating microglia activation

Neuroinflammation is a key mechanism underlying the cognitive impairment induced by PM_2.5, and activated microglia plays an important role in this process. However, the mechanisms by which activated microglia induced by PM_2.5 impair hippocampal neurons have not been fully elucidated. In this study, we focused on the role of HMGB1-NLRP3-P2X7R pathway which mediated the microglia activation in hippocampal neurons impairment induced by PM_2.5 using a co-culture model of microglia and hippocampal neurons. We found that PM_2.5 resulted in activated microglia and HMGB1-NLRP3 inflammatory pathway, and elevated proinflammatory cytokines of IL-18 and IL-1β in a dose-dependent manner. Notably, we next utilized previously reported pharmacological inhibitors or siRNA for HMGB1 and found that they significantly inhibited the activation of downstream NLRP3 and MAPK pathways derived from PM_2.5 exposure, and down-regulated IL-18 and IL-1β in microglia. Furthermore, we employed co-cultured hippocampal neurons and microglia and found that reducing HMGB1 significantly decreased neuron impairment, apoptosis related protein of cl-caspase3, synaptic damage, and neurotransmitter receptor of 5-HT2A, along with notably elevated presynaptic and postsynaptic proteins of SYP and PSD-95, as well as learning and memory related proteins of p-CREB and BDNF. The neuronal impairment induced by PM_2.5 could not be prevented in the case of simultaneous employment of HMGB1 siRNA and NLRP3 agonist. After silencing NLRP3 alone in microglia, hippocampal neurons demonstrated decreased excessive autophagy and up-regulated synaptic protein of GAP43 as well as learning and memory related protein of NCAM1. Therefore, we further studied how hippocampal neurons affected microglia under PM_2.5 exposure, Further investigation indicated that silencing HMGB1 could affect the activation of P2X7R and reduce the release of ATP from hippocampal neurons, thus protecting the interaction between microglia and hippocampal neurons. The present work suggests that regulation of HMGB1-NLRP3-P2X7R pathway can inhibit the microglia activation induced by PM_2.5 to alleviate hippocampal neuron impairment and stabilize the microenvironment between microglia and neurons. This contributes to maintaining the normal function of hippocampal neurons and alleviating the cognitive impairment derived from PM_2.5 exposure.

Full-Length Transcriptome Sequencing Analysis of Differentially Expressed Genes and Pathways After Treatment of Psoriasis With Oxymatrine

Psoriasis is a recurrent chronic inflammatory skin disease. Unlike many of the latest psoriasis treatments that only confer limited curative effects and have certain side effects, oxymatrine effectively improves severe plaque psoriasis with mild adverse reactions. Here, we explored the genes and pathways underlying the effects of oxymatrine on psoriasis. Briefly, patients with severe plaque psoriasis were treated with oxymatrine and their lesioned skin samples were sequenced by full-length transcriptomics. Next, the differentially expressed genes (DEGs) in psoriatic lesions were identified and compared in oxymatrine-treated patients and healthy controls, their genes were functionally annotated, and protein–protein interaction network analysis and immunohistochemistry were performed. Both Psoriasis Area and Severity Index (PASI) and Body Surface Area (BSA) scores were recovered significantly from all 16 patients (all p < 0.001). The number of DEGs in patients before and after oxymatrine treatment was 4232, and 4105 DEGs were found between the psoriasis group (before oxymatrine treatment) and the normal control group [p < 0.01, |log₂ fold change, (FC)| >1.5]. While most of the DEGs recovered significantly after oxymatrine treatment, only 650 DEGs were observed between the psoriasis group (after oxymatrine treatment) and the normal control group (p < 0.01, |log₂FC|> 1.5). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that 64 pathways were significantly activated after oxymatrine treatment (p < 0.05). Only 12 pathways were statistically significant between after oxymatrine treatment and the normal control group (p < 0 .05). Among all the restored pathways, the improvement of the IL-17 signaling pathway was the most significant (p = 1.18E-06). Gene loci of oxymatrine action was assessed by protein interaction analysis on 205 DEGs that were co-expressed in 5 patients before and after oxymatrine treatment (p < 0.05, FC > 1.5). After oxymatrine treatment, the expression of two mitosis-related genes namely, cyclin dependent kinase 1 (CDK1) and cyclin B1 (CCNB1), that affect cell proliferation recovered significantly. In light of these results, we conclude that oxymatrine likely alters the abnormal expression of some genes and pathways in psoriasis patients. Multipathway and multitarget therapy can greatly ameliorate abnormalities in genes and pathways and effectively treat psoriasis. Importantly, among the DEGs, the proliferation-related genes, such as CDK1 and CCNB1, are likely important targets for treating psoriasis by oxymatrine. We believe that these findings may lead to a new treatment strategy for psoriasis.

Neuroprotective Effect of Dioscin against Parkinson’s Disease via Adjusting Dual-Specificity phosphatase 6(DUSP6)-Mediated Oxidative Stress

Exploration of lead compounds against Parkinson’s disease (PD), a neurodegenerative disease, is of great important. Dioscin, a bioactive natural product, shows various pharmacological effects. However, the activities and mechanisms of dioscin against PD have not been well investigated. In this study, the tests on 6-hydroxydopamine (6-OHDA)-induced PC12 cells and rats were carried out. The results showed that dioscin dramatically improved cell viability, decreased reactive oxygen species (ROS) levels, improved motor behavior and tyrosine hydroxylase(TH) levels and restored the levels of glutathione (GSH) and malondialdehyde (MDA) in rats. Mechanism investigation showed that dioscin not only markedly increased the expression level of dual- specificity phosphatase 6 (DUSP6) by 1.87-fold in cells and 2.56-fold in rats, and decreased phospho-extracellular regulated protein kinases (p-ERK) level by 2.12-fold in cells and 2.34-fold in rats, but also increased the levels of nuclear factor erythroid2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), superoxide dismutase (SOD) and decreased the levels of kelch-1ike ECH-associated protein l (Keap1) in vitro and in vivo. Furthermore, DUSP6 siRNA transfection experiment in PC12 cells validated the protective effects of dioscin against PD via regulating DUSP6 to adjust the Keap1/Nrf2 pathway. Our data supported that dioscin has protection against PD in regulating oxidative stress via DUSP6 signal, which should be considered as an efficient candidate for the treatment of PD in the future.

Cathepsin D as biomarker in CSF of nusinersen-treated patients with spinal muscular atrophy

BACKGROUND

The therapeutic landscape of spinal muscular atrophy (SMA) has changed dramatically during the last 4 years but treatment responses differ remarkably between individuals and therapeutic decision-making remains challenging - underlining the persistent need for validated biomarkers.

METHODS

We applied untargeted proteomic analyses to determine biomarkers in cerebrospinal fluid (CSF) samples of SMA patients under treatment with nusinersen. Identified candidate proteins were validated in CSF samples of SMA patients by Western blot and ELISA. Further, levels of peripheral neurofilament H and L were determined.

RESULTS

Untargeted proteomic analysis of CSF samples of 3 SMA type 1 patients revealed the lysosomal protease Cathepsin D as a candidate biomarker. Subsequent validation analysis in a larger cohort of 31 pediatric SMA patients (type 1=12, type 2=9, type 3=6, presymptomatically treated=4; age 0-16 years) revealed a significant decline of Cathepsin D levels in SMA patients ≥2 months at the start of treatment. While evident in all older age categories, this decline was only significant in the group of patients that showed a positive motor-response. Moreover, downregulation of Cathepsin D was evident in muscle biopsies of SMA patients.

CONCLUSIONS

We identified a decline of Cathepsin D levels in CSF samples of SMA patients under nusinersen treatment that was more pronounced in the group of 'treatment responders' than in 'non-responders'. We believe that our results indicate a suitability of Cathepsin D levels as possible biomarker in SMA also in older patients - in combination with analysis of pNF-L in adolescents or alone in adult patients.

Potential Therapeutic Applications of Plant-Derived Alkaloids against Inflammatory and Neurodegenerative Diseases

Alkaloids are a type of natural compound possessing different pharmacological activities. Natural products, including alkaloids, which originate from plants, have emerged as potential protective agents against neurodegenerative disorders (NDDs) and chronic inflammations. A wide array of prescription drugs are used against these conditions, however, not free of limitations of potency, side effects, and intolerability. In the context of personalized medicine, further research on alkaloids to unravel novel therapeutic approaches in reducing complications is critical. In this review, a systematic survey was executed to collect the literature on alkaloids and their health complications, from which we found that majority of alkaloids exhibit anti-inflammatory action via nuclear factor-κB and cyclooxygenase-2 (COX-2), and neuroprotective interaction through acetylcholinesterase (AChE), COX, and β-site amyloid precursor protein activity. In silico ADMET and ProTox-II-related descriptors were calculated to predict the pharmacological properties of 280 alkaloids isolated from traditional medicinal plants towards drug development. Out of which, eight alkaloids such as tetrahydropalmatine, berberine, tetrandrine, aloperine, sinomenine, oxymatrine, harmine, and galantamine are found to be optimal within the categorical range when compared to nicotine. These alkaloids could be exploited as starting materials for novel drug synthesis or, to a lesser extent, manage inflammation and neurodegenerative-related complications.

Treadmill exercise alleviates neuronal damage by suppressing NLRP3 inflammasome and microglial activation in the MPTP mouse model of Parkinson's disease

Treadmill exercise has been recognized as an effectively therapeutic strategy for Parkinson's disease (PD). However, its exact molecular mechanism of promoting PD remain unclear. Recently, the NLRP3 inflammasome is considered to play a critical role in the pathogenesis of PD. In this study, we investigated whether NLRP3 inflammasome was involved in treadmill exercise-induced neuroprotection and anti-inflammation effect in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD. 8-week-old male mice (C57BL/6 strain) were divided into four groups: Control, MPTP, MPTP + EX and EX. MPTP was intraperitoneally injected into mice to establish chronic PD model. The open-field test and pole test were used to assess motor function. The results showed that treadmill exercise significantly alleviated motor dysfunction and dopaminergic neuron degeneration induced by MPTP. In addition, we also found that treadmill exercise suppressed MPTP-triggered microglia activation and the co-localization of NLRP3+/Iba-1+ cells in the substantia nigra. These effects were associated with suppression NLRP3 inflammasome via down-regulation of TLR4/MyD88/NF-κB pathway. Overall, our study demonstrated that treadmill exercise could effectively alleviates neuronal damage via inhibition of NLRP3 inflammasome and microglial activation in MPTP-induced PD mouse model.

Cathepsin D-Managing the Delicate Balance

Lysosomal proteases play a crucial role in maintaining cell homeostasis. Human cathepsin D manages protein turnover degrading misfolded and aggregated proteins and favors apoptosis in the case of proteostasis disruption. However, when cathepsin D regulation is affected, it can contribute to numerous disorders. The down-regulation of human cathepsin D is associated with neurodegenerative disorders, such as neuronal ceroid lipofuscinosis. On the other hand, its excessive levels outside lysosomes and the cell membrane lead to tumor growth, migration, invasion and angiogenesis. Therefore, targeting cathepsin D could provide significant diagnostic benefits and new avenues of therapy. Herein, we provide a brief overview of cathepsin D structure, regulation, function, and its role in the progression of many diseases and the therapeutic potentialities of natural and synthetic inhibitors and activators of this protease.

Oxymatrine Extends Survival by Attenuating Neuroinflammation in a Mouse Model of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is one of the leading causes of death associated with neurodegenerative diseases worldwide, and the progression of the disease is characteristically accompanied by severe neuroinflammation. Neuroprotective effects of oxymatrine (OMT) were shown to be due to reduced neuroinflammation in the mouse models of Alzheimer's disease and Parkinson's disease. The present study investigated whether OMT has a therapeutic potential in transgenic SOD1-G93A (TgSOD1-G93A) mice. Daily OMT treatment started at the age of 55 days until the end stage of the disease. Body weight and rotarod motor performance were assessed every 3 days starting from 70 days of age. Footprints were recorded to measure the stride length 40 days and 60 days after the initiation of the treatment. Some animals were sacrificed at the age of 115 days, and the lumbar spinal cord was harvested for immunofluorescence and quantitative real-time polymerase chain reaction (qRT-PCR) to evaluate the neuroinflammatory responses. The results indicated that treatment with OMT delayed body weight loss, improved motor performance, and prolonged the survival of SOD1-G93A mice. Mechanistically, OMT treatment enhanced motor neuronal survival and alleviated the activation of microglia and astrocytes compared with those in the vehicle-treated group. Furthermore, the expression of the proinflammatory mediators was downregulated, and the expression of the anti-inflammatory factors was upregulated in the OMT-treated group compared with those in the vehicle-treated group (P < 0.05). Thus, the treatment with OMT had neuroprotective effects, promoting neuronal survival and extending the lifetime of SOD1-G93A mice by suppressing neuroinflammation.

Cannabidiol Induces Autophagy to Protects Neural Cells From Mitochondrial Dysfunction by Upregulating SIRT1 to Inhibits NF-κB and NOTCH Pathways

The protective effect of Cannabidiol on Parkinson’s disease (PD) has been found in recent study. However, the specific mechanism of the protective effect of Cannabidiol on PD nerve damage require further exploration. This study aims to investigate effect of Cannabidiol on MMP-induced Neural Cells (SH-SY5Y) mitochondrial dysfunction. MMP⁺ and Cannabidiol were used to treat SH-SY5Y cells, the cells viability was measured by MTT assay. The expression of Tyrosine hydroxylase (TH) in cells was measured by western blotting and Immunofluorescence staining. The relationship among Cannabidiol, Silent mating type information regulation 2 homolog-1 (SIRT1) and NOTCH signaling, NF-κB signaling was examined by western blotting. The effect of Cannabidiol on MMP⁺-induced mitochondrial dysfunction of SH-SY5Y cells was measured by western blotting. Cannabidiol alleviated loss of TH expression and cytotoxicity in the MPP⁺-induced SH-SY5Y cells. Further mechanistic investigation showed that Cannabidiol induced SH-SY5Y cells autophagy to protects cells from mitochondrial dysfunction by upregulating SIRT1 to Inhibits NF-κB and NOTCH Pathways. Taken together, Cannabidiol acts as a protector in PD.