The pathogenesis of Parkinson's disease is closely related to genetic factors. This article has systematically reviewed the research progress of molecular genetic mechanism on Parkinson's disease by focusing on the role of six high-penetrance pathogenic genes (SNCA, LRRK2, PRKN, PINK1, PARK7, and VPS35) and some risk genes (such as GBA1). These genetic variants eventually converge in three core pathogenic biological pathways, including lysosomal-autophagy pathway disorder, mitochondrial quality control disorder and α-synuclein metabolic abnormality. In-depth understanding of these molecular mechanisms is of great significance for the development of targeted therapy and realization of precision medicine for this disease.
Humans ; Parkinson Disease/metabolism* ; alpha-Synuclein/genetics* ; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics* ; Genetic Predisposition to Disease ; Protein Kinases/genetics* ; Animals ; Glucosylceramidase/genetics* ; Ubiquitin-Protein Ligases/genetics*

BACKGROUND: Iron deposition plays a crucial role in the pathophysiology of Parkinson's disease (PD), yet the distribution pattern of iron deposition in the subcortical nuclei has been inconsistent across previous studies. We aimed to assess the difference patterns of iron deposition detected by quantitative iron-sensitive magnetic resonance imaging (MRI) between patients with PD and patients with atypical parkinsonian syndromes (APSs), and between patients with PD and healthy controls (HCs). METHODS: A systematic literature search was conducted on PubMed, Embase, and Web of Science databases to identify studies investigating the iron content in PD patients using the iron-sensitive MRI techniques (R2 * and quantitative susceptibility mapping [QSM]), up until May 1, 2023. The quality assessment of case-control and cohort studies was performed using the Newcastle-Ottawa Scale, whereas diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies-2. Standardized mean differences and summary estimates of sensitivity, specificity, and area under the curve (AUC) were calculated for iron content, using a random effects model. We also conducted the subgroup-analysis based on the MRI sequence and meta-regression. RESULTS: Seventy-seven studies with 3192 PD, 209 multiple system atrophy (MSA), 174 progressive supranuclear palsy (PSP), and 2447 HCs were included. Elevated iron content in substantia nigra (SN) pars reticulata ( P <0.001) and compacta ( P <0.001), SN ( P <0.001), red nucleus (RN, P <0.001), globus pallidus ( P <0.001), putamen (PUT, P = 0.021), and thalamus ( P = 0.029) were found in PD patients compared with HCs. PD patients showed lower iron content in PUT ( P <0.001), RN ( P = 0.003), SN ( P = 0.017), and caudate nucleus ( P = 0.017) than MSA patients, and lower iron content in RN ( P = 0.001), PUT ( P <0.001), globus pallidus ( P = 0.004), SN ( P = 0.015), and caudate nucleus ( P = 0.001) than PSP patients. The highest diagnostic accuracy distinguishing PD from HCs was observed in SN (AUC: 0.85), and that distinguishing PD from MSA was found in PUT (AUC: 0.90). In addition, the best diagnostic performance was achieved in the RN for distinguishing PD from PSP (AUC: 0.86). CONCLUSIONS: Quantitative iron-sensitive MRI could quantitatively detect the iron content of subcortical nuclei in PD and APSs, while it may be insufficient to accurately diagnose PD. Future studies are needed to explore the role of multimodal MRI in the diagnosis of PD. REGISTRISION PROSPERO (CRD42022344413).
Humans ; Parkinson Disease/diagnostic imaging* ; Magnetic Resonance Imaging/methods* ; Iron/metabolism*

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons and the accumulation of Lewy bodies, leading to motor and nonmotor symptoms. While both genetic and environmental factors contribute to PD, recent studies highlight the crucial role of lipid metabolism disturbances in disease progression. Altered lipid homeostasis promotes protein aggregation and oxidative stress, with significant changes in lipid classes such as sphingolipids and glycerolipids observed in patients with PD. These disturbances are involved in key pathological processes, such as α-synuclein aggregation, organelle dysfunction, lipid-mediated neuroinflammation, and impaired lipid homeostasis. This review examines the relationship between lipid species and PD progression, focusing on the physiological roles of lipids in the central nervous system. It explores the mechanistic links between lipid metabolism and PD pathology, along with lipid-related genetic risk factors. Furthermore, this review discusses lipid-targeting therapeutic strategies to mitigate PD progression, emphasizing the potential of lipid modulation for effective treatment development.
Humans ; Parkinson Disease/metabolism* ; Lipid Metabolism/physiology* ; Animals ; Oxidative Stress/physiology* ; alpha-Synuclein/metabolism*

The study aimed to investigate the effect of the CD200R1 gene deletion on microglia activation and nigrostriatal dopamine neuron loss in the Parkinson's disease (PD) process. The CRISPR-Cas9 technology was applied to construct the CD200R1^-/- mice. The primary microglia cells of wild-type and CD200R1^-/- mice were cultured and treated with bacterial lipopolysaccharide (LPS). Microglia phagocytosis level was assessed by a fluorescent microsphere phagocytosis assay. PD mouse model was prepared by nigral stereotaxic injection of recombinant adeno-associated virus vector carrying human α-synuclein (α-syn). The changes in the motor behavior of the mice with both genotypes were evaluated by cylinder test, open field test, and rotarod test. Immunohistochemical staining was used to assess the loss of dopamine neurons in substantia nigra. Immunofluorescence staining was used to detect the expression level of CD68 (a key molecule involved in phagocytosis) in microglia. The results showed that CD200R1 deletion markedly enhanced LPS-induced phagocytosis in vitro by the microglial cells. In the mouse model of PD, CD200R1 deletion exacerbated motor behavior impairment and dopamine neuron loss in substantia nigra. Fluorescence intensity analysis results revealed a significant increase in CD68 expression in microglia located in the substantia nigra of CD200R1^-/- mice. The above results suggest that CD200R1 deletion may further activates microglia by promoting microglial phagocytosis, leading to increased loss of the nigrostriatal dopamine neurons in the PD model mice. Therefore, targeting CD200R1 could potentially serve as a novel therapeutic target for the treatment of early-stage PD.
Animals ; Microglia/physiology* ; Mice ; Phagocytosis ; Parkinson Disease/genetics* ; Disease Models, Animal ; Receptors, Cell Surface/physiology* ; Dopaminergic Neurons/pathology* ; Antigens, CD/metabolism* ; Gene Deletion ; Substantia Nigra ; Mice, Inbred C57BL ; Mice, Knockout ; Cells, Cultured ; Male ; alpha-Synuclein ; CD68 Molecule ; Orexin Receptors

Currently, the incidence of Parkinson's disease (PD) is on the rise. More and more evidences suggest that mitochondrial dysfunction plays a crucial role in the etiology of PD, and dysfunction of mitochondrial complex I (MCI) is one of the most critical factors leading to mitochondrial dysfunction. On one hand, MCI dysfunction stimulates dopaminergic neurons to produce reactive oxygen species (ROS). On the other hand, MCI dysfunction decreases dopaminergic neuron viability and reduces ATP production. All these outcomes promote the pathological progression of PD. This review summarizes research progress on the role of MCI in the pathogenesis of PD, as well as PD treatment strategies based on MCI.
Parkinson Disease/metabolism* ; Humans ; Electron Transport Complex I/metabolism* ; Mitochondria/physiology* ; Reactive Oxygen Species/metabolism* ; Dopaminergic Neurons/metabolism* ; Animals ; Adenosine Triphosphate/metabolism*

The etiology of nervous system diseases is complicated, posing significant harm to patients and often resulting in poor prognoses. In recent years, the role of dopaminergic system in nervous system diseases has attracted much attention, and its complex regulatory mechanism and therapeutic potential have been gradually revealed. This paper reviews the role of dopaminergic neurons, the neurotransmitter dopamine, dopamine receptors and dopamine transporters in neurological diseases (including Alzheimer's disease, Parkinson's disease and schizophrenia), with a view to further elucidating the disease mechanism and providing new insights and strategies for the treatment of neurological diseases.
Humans ; Dopamine/metabolism* ; Nervous System Diseases/physiopathology* ; Parkinson Disease/physiopathology* ; Receptors, Dopamine/metabolism* ; Dopaminergic Neurons/physiology* ; Dopamine Plasma Membrane Transport Proteins/metabolism* ; Alzheimer Disease/physiopathology* ; Schizophrenia/physiopathology* ; Animals

OBJECTIVE: To explore the improvement effect of electroacupuncture (EA) based on Xingnao Kaiqiao acupuncture (acupuncture for regaining consciousness and opening orifices) on cognitive impairment in mice with Parkinson's disease (PD), and to explore its regulatory mechanisms on the kinesin family member 5A (KIF5A)/mitochondrial Rho GTPase 1 (Miro1) pathway and mitophagy in prefrontal cortical neurons. METHODS: A total of 70 male C57BL/6J mice of clean grade were randomly divided into a normal group (12 mice), a sham operation group (12 mice), and a model pre-screening group (46 mice). Unilateral stereotaxic injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle was adopted to establish the PD model in the model pre-screening group. Twenty-four mice after successful modeling were randomly selected and divided into a model group and an EA group, 12 mice in each one. In the EA group, acupuncture was applied at "Shuigou" (GV26) and bilateral "Sanyinjiao" (SP6) and "Neiguan" (PC6), ipsilateral "Sanyinjiao" (SP6) and "Neiguan" (PC6) were connected to EA respectively, with disperse-dense wave, 5 Hz/20 Hz in frequency, 0.5 mA in current intensity, 20 min a time, 6 times a week for 30 days. Cognitive function was assessed by Y-maze and Morris water maze tests; morphology of prefrontal cortex was observed by H.E. staining; reactive oxygen species (ROS) level in prefrontal cortex was detected by fluorescence probe method; mitochondrial morphology and autophagosome ultrastructure were observed by transmission electron microscopy; the mRNA expression of tyrosine hydroxylase (TH) was detected by quantitative real-time PCR; the protein expression of TH, KIF5A, Miro1, p62, Parkin and PTEN induced kinase 1 (PINK1) was detected by Western blot. RESULTS: Compared with the sham operation group, both the model group and the EA group exhibited increased rotation number of per minute (P<0.001). Compared with the sham operation group, in the model group, the novel arm exploration time of Y-maze test was shortened (P<0.001), the escape latency of Morris water maze test was prolonged (P<0.05) and the platform crossing number of Morris water maze test was reduced (P<0.01); in the prefrontal cortex, the number of cellular vacuole and neurons with karyopyknosis was increased (P<0.001), and mitochondrial autophagosomes could be observed; in the prefrontal cortex, the relative expression of ROS was increased (P<0.001), the protein and mRNA expression of TH was decreased (P<0.001), the protein expression of Miro1, PINK1, Parkin was increased (P<0.001, P<0.01), the protein expression of KIF5A and p62 was decreased (P<0.001). Compared with the model group, in the EA group, the novel arm exploration time of Y-maze test was prolonged (P<0.01), the escape latency of Morris water maze test was shortened (P<0.05) and the platform crossing number of Morris water maze test was increased (P<0.05); in the prefrontal cortex, the number of cellular vacuole and neurons with karyopyknosis was decreased (P<0.001), and the number of mitochondrial autophagosomes reduced and the mitochondrial morphology was improved; in the prefrontal cortex, the relative expression of ROS was decreased (P<0.01), the protein and mRNA expression of TH was increased (P<0.001, P<0.01), the protein expression of Miro1, PINK1, Parkin was decreased (P<0.001, P<0.01, P<0.05), the protein expression of KIF5A and p62 was increased (P<0.01, P<0.05). CONCLUSION Xingnao Kaiqiao electroacupuncture effectively alleviates cognitive impairment and damage of neuronal function in PD mice, its mechanism may be related to the regulation of KIF5A/Miro1 pathway, hence reducing the mitophagy in prefrontal cortical neurons.
Animals ; Electroacupuncture ; Male ; Mice ; Parkinson Disease/physiopathology* ; Cognitive Dysfunction/psychology* ; Kinesins/genetics* ; Humans ; Mitophagy ; Mice, Inbred C57BL ; rho GTP-Binding Proteins/genetics* ; Mitochondria/genetics* ; Prefrontal Cortex/metabolism*

OBJECTIVE: To observe the effects of electroacupuncture (EA) on improving motor function and regulating microglial activation based on Notch receptor 1 (Notch1)/Hes family bHLH transcription factor 1 (Hes1) pathway in mice with Parkinson's disease (PD). METHODS: Thirty-six male C57BL/6 mice were randomly divided into a control group, a model group and an EA group, 12 mice in each group. PD model was established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 7 consecutive days in the model group and the EA group. From the 1st day of modeling, EA was applied at "Baihui" (GV20) and bilateral "Shenshu" (BL23) in the EA group, with continuous wave, in frequency of 2 Hz and current of 2 mA, 15 min a time, once a day for 14 days continuously. The behavioral performance was evaluated by gait test, pole climbing test and hanging test, the number of positive cells of tyrosine hydroxylase (TH) and the co-expression positive cells of Notch1/ionized calcium binding adaptor molecule 1 (Iba-1) in the substantia nigra of midbrain was assessed by immunofluorescence, the protein expression of TH, α-synuclein (α-syn), Notch1, Hes1, Iba-1, inducible nitric oxide synthase (iNOS), Arginase-1 (ARG1), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and IL-10 was detected by Western blot, the mRNA expression of Notch1 and Hes1 was detected by real-time PCR. RESULTS: Compared with the control group, in the model group, the stride frequency was accelerated (P<0.001) and the stride length was shortened (P<0.001) for the four limbs, the pole climbing test time was prolonged (P<0.01) and the grip level was reduced (P<0.01); in the substantia nigra of midbrain, the number of positive cells of TH was decreased (P<0.001), the number of co-expression positive cells of Notch1/Iba-1 was increased (P<0.001), the protein expression of α-syn, Notch1, Hes1, Iba-1, iNOS, TNF-α, IL-1βand IL-6 was increased (P<0.01, P<0.05, P<0.001), the protein expression of TH, ARG1 and IL-10 was decreased (P<0.01, P<0.001), the mRNA expression of Notch1 and Hes1 was increased (P<0.01). Compared with the model group, in the EA group, the stride frequency was decelerated (P<0.001) and the stride length was increased (P<0.05, P<0.01, P<0.001) for the four limbs, the pole climbing test time was shortened (P<0.05) and the grip level was increased (P<0.05); in the substantia nigra of midbrain, the number of positive cells of TH was increased (P<0.01), the number of co-expression positive cells of Notch1/Iba-1 was decreased (P<0.001), the protein expression of α-syn, Notch1, Hes1, Iba-1, iNOS, TNF-α, IL-6 and IL-1β was decreased (P<0.05, P<0.01), the protein expression of TH, ARG1 and IL-10 was increased (P<0.05, P<0.001, P<0.01), the mRNA expression of Notch1 and Hes1 was decreased (P<0.05). CONCLUSION EA can improve the behavioral performance and protect the dopaminergic neurons in PD mice, its mechanism may relate to the inhibition of Notch1/Hes1-mediated neuroinflammation, thus inhibiting the microglial activation.
Animals ; Electroacupuncture ; Microglia/metabolism* ; Male ; Receptor, Notch1/metabolism* ; Parkinson Disease/physiopathology* ; Transcription Factor HES-1/metabolism* ; Mice ; Mice, Inbred C57BL ; Humans ; Signal Transduction

OBJECTIVE: To observe the effects of acupoint catgut embedding (ACE) on gut microbiota and fecal short-chain fatty acids (SCFAs) levels in patients with Parkinson's disease (PD) with constipation. METHODS: A total of 80 PD patients with constipation were randomly divided into an observation group and a control group, 40 cases in each group. Additionally, 40 healthy individuals were recruited as a healthy control group. The control group received conventional Western medical treatment for PD combined with polyethylene glycol (PEG), once daily for eight weeks. The observation group received additional ACE treatment at bilateral Tianshu (ST25), Zusanli (ST36), and Shangjuxu (ST37), once every two weeks for eight weeks. The healthy control group received no intervention. The spontaneous bowel movements (SBMs) per week and patient assessment of constipation quality of life (PAC-QOL) scores were assessed at baseline and after treatment in the two groups. Fecal samples were collected at the end of treatment for the observation and the control groups and at baseline for the healthy control group. Gut microbiota composition and diversity were analyzed using 16S rRNA method, and SCFA levels were measured using high-performance liquid chromatography (HPLC). RESULTS: Compared before treatment, the observation group showed a significant increase in SBMs (P<0.01), and PAC-QOL scores including physical discomfort, psychosocial discomfort, worry and concern, and total score were significantly reduced (P<0.01) after treatment; the control group also showed a reduction in PAC-QOL total score after treatment (P<0.01). After treatment, the observation group had significantly more SBMs (P<0.01), and lower PAC-QOL physical discomfort, psychosocial discomfort, worry and concern scores, and total score (P<0.01), and higher PAC-QOL satisfaction score (P<0.01) than the control group. Compared with the healthy control group, the control group showed decreased Chao1 and Ace indices (P<0.01). Compared with the healthy control group, the relative abundance of Prevotella and Roseburia was increased (P<0.05), while that of Enterobacter and Ruminococcus torques (six species in total) was decreased (P<0.05) in the control group. Compared with the control group, the observation group had increased relative abundance of Dialister, Parabacteroides, and Ruminococcus torques (P<0.05), and decreased relative abundance of Prevotella and Eubacterium ruminantium (P<0.05). Compared with the healthy control group, the control group had increased fecal SCFA levels (P<0.05); compared with the control group, the observation group had reduced fecal SCFA levels (P<0.05). Compared with the healthy control group, acetic acid, propionic acid, and butyric acid levels were elevated in the control group (P<0.05); compared with the control group, acetic acid, propionic acid, and butyric acid levels were decreased in the observation group (P<0.05). CONCLUSION ACE could increase spontaneous bowel movements and improve the quality of life in PD patients with constipation, which may be related to the regulation of gut microbiota composition and SCFA levels.
Humans ; Constipation/metabolism* ; Male ; Gastrointestinal Microbiome ; Acupuncture Points ; Female ; Middle Aged ; Parkinson Disease/complications* ; Aged ; Fatty Acids, Volatile/metabolism* ; Catgut ; Feces/microbiology* ; Acupuncture Therapy ; Quality of Life ; Adult

The aim of this study is to investigate the protective effect of idebenone (IDE) combined with borneol (BO) against Parkinson's disease (PD). In this study, wild-type AB zebrafish and transgenic Tg ( vmat2: GFP) zebrafish with green fluorescence labeled dopamine neurons were used to establish the PD model with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP). Following drug treatment, the behavioral performance and dopamine neuron morphology of zebrafish were evaluated, and regulation of dopamine signaling pathway-related genes was determined using RT-qPCR. The results showed that IDE combined with BO improved the behavioral disorders of zebrafish such as bradykinesia and shortening movement distance, also effectively reversed the damage of MPTP-induced dopaminergic neurons. At the same time, the expression of dopamine synthesis and transportation-related genes was up-regulated, and the normal function of the signal transduction pathway was restored. The combination showed a better therapeutic effect compared to the IDE monotherapy group. This study reveals the protective mechanism of IDE combined with BO on the central nervous system for the first time, which provides an important experimental basis and theoretical reference for clinical combination strategy in PD treatment.
Animals ; Zebrafish ; Signal Transduction/drug effects* ; Animals, Genetically Modified ; Dopamine/metabolism* ; Neuroprotective Agents/pharmacology* ; Disease Models, Animal ; Camphanes/pharmacology* ; Ubiquinone/pharmacology* ; Parkinson Disease/drug therapy* ; Dopaminergic Neurons/metabolism*