While the level of α-synuclein oligomers (α-SOs) in the CSF of patients with Parkinson’s disease (PD) is consistently increased, its pathogenic role in PD remains poorly understood. This study focuses on the role of CSF-derived α-SOs in PD pathology. We demonstrated that CSF-derived α-synuclein enters the brain via perivascular spaces, which was more abundant in the olfactory bulb (OB) than in the substantia nigra (SN). We also found that neuroinflammation was more pronounced in the OB than in the SN following α-SOs injection. α-SOs-treated mice exhibited an early and persistent loss of dopaminergic (DA) neurons in the OB, along with olfactory deficit. Conversely, DA neuron loss in the SN occurred later and was associated with motor dysfunction. Furthermore, reducing α-SOs dose alleviated OB pathology. These findings suggest that perivascular spread of CSF-derived α-SOs induces region-specific PD-like pathology, indicating that removing CSF-derived α-SOs could slow PD progression.

Introduction Parkinson’s disease (PD) progression is strongly associated with sleep disturbances, but the molecular mechanisms linking sleep loss to PD pathology remain poorly understood. Emerging evidence implicates impaired glymphatic clearance of pathological α-synuclein (α-syn) as a key factor, though how sleep deprivation disrupts this process is unclear. Objectives This study aimed to determine whether sleep deprivation exacerbates PD pathology by modulating lymphocyte-activation gene 3 (LAG3) expression in astrocytes, thereby impairing glymphatic system function and promoting α-syn accumulation. Methods We injected α-syn preformed fibrils (PFF) into the striatum of A53T transgenic mice and subjected them to sleep deprivation. Glymphatic function was assessed using in vivo magnetic resonance imaging and fluorescent tracer-based clearance assays. Astrocytic LAG3 expression was evaluated by transcriptomic sequencing and validated by immunostaining and qPCR. Adeno-associated virus-mediated LAG3 knockdown in astrocytes was used to test causality. Results Sleep deprivation significantly worsened motor deficits, dopaminergic neuron loss, and α-syn pathology in PD mice. It induced astrocyte reactivity and disrupted aquaporin-4 (AQP4) polarization, leading to impaired cerebrospinal fluid influx and reduced α-syn clearance. LAG3 was selectively upregulated in astrocytes under sleep-deprived conditions and promoted α-syn PFF internalization. Knockdown of astrocytic LAG3 restored AQP4 polarization, improved glymphatic clearance, and attenuated neurodegeneration and behavioral deficits. Conclusion Our findings identify astrocytic LAG3 as a critical mediator linking sleep deprivation to glymphatic dysfunction and PD progression. Targeting LAG3 may represent a promising, albeit early-stage, therapeutic strategy to mitigate α-syn pathology in PD patients with sleep disorders.

INTRODUCTION:Neonatal stress disrupts brain development and increases the risk of neurological disorders later in life. However, the impact of neonatal stress on the development of the glymphatic system and susceptibility to Parkinson's disease (PD) remains largely unknown. METHODS:Neonatal maternal deprivation (NMD) was performed on mice for 14 consecutive days to model chronic neonatal stress. Adeno-associated virus expressing A53T-α-synuclein (α-syn) was injected into the substantia nigra to establish PD model mice. Glymphatic activity was determined using in vivo magnetic resonance imaging, ex vivo fluorescence imaging and microplate assay. The transcription and expression of aquaporin-4 (AQP4) and other molecules were evaluated by qPCR, western blotting, and immunofluorescence. Animal's responses to NMD and α-syn overexpression were observed using behavioral tests. RESULTS:Glymphatic activity was impaired in adult NMD mice. AQP4 polarization and platelet-derived growth factor B (PDGF-B) signaling were reduced in the frontal cortex and hippocampus of both young and adult NMD mice. Furthermore, exogenous α-syn accumulation was increased and PD-like symptoms were aggravated in adult NMD mice. CONCLUSION:The results demonstrated that NMD could disrupt the development of the glymphatic system through PDGF-B signaling and increase the risk of PD later in life, indicating that alleviating neonatal stress could be beneficial in protecting the glymphatic system and reducing susceptibility to neurodegeneration.

Introduction: Previous studies have predominantly explored the relationship of the glymphatic system with motor symptoms in Parkinson's disease (PD); however, research on non-motor symptoms remains limited. Therefore, this study investigated the association between glymphatic function and non-motor symptoms, including cognitive impairment and sleep disorders, in PD patients. Methods: This study recruited 49 PD patients and 38 healthy controls (HC). Glymphatic function was evaluated using enlarged perivascular spaces (EPVS) in the basal ganglia (BG) region and diffusion tensor image analysis along the perivascular space (DTIALPS) index. Cognition, sleep, anxiety, and depression scales were assessed in all participants. According to the scale scores, PD patients were further divided into several groups to identify the presence of non-motor symptoms. Differences in EPVS numbers and ALPS index between PD subgroups and HC group were compared. Spearman correlation analysis was performed to investigate the association between the PD non-motor symptoms and ALPS index. Additionally, receiver operating characteristic (ROC) curves analysis was conducted for ALPS index to predict cognitive impairment and insomnia in PD patients. Results: PD patients with and without non-motor symptoms all showed more EPVS numbers than the controls, and the EPVS numbers in PD patients with cognitive impairment were also greater than those without. Notably, except for the depression subgroup, PD patients with non-motor symptoms showed significantly lower ALPS index than the controls. The Montreal Cognitive Assessment (MoCA) scores were positively correlated, whereas the Parkinson's Disease Sleep Scale (PDSS)-2 and REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ) scores were negatively correlated with the ALPS index in PD patients (r=0.3618, P=0.0053; r=-0.4146, P=0.0015; r=-0.2655, P=0.0326, respectively). The ALPS index proved to be predictive of cognitive impairment and insomnia in PD Conclusion: Glymphatic function is closely associated with cognition and sleep of PD patients.

胶质淋巴系统(GS)是由星形胶质细胞终足上的水孔蛋白4(AQP4)介导的脑脊液和脑组织液交换流动系统,主要作用在于运输营养和清除脑内废物等.MRI能直接、迅速、无创显示脑脊液流动,可用于研究GS.本文就MRI研究GS进展进行综述.

BackgroundThe glymphatic system is reportedly involved in Parkinson's disease (PD). Based on previous studies, we aimed to confirm the correlation between the glymphatic system and PD progression by combining two imaging parameters, diffusion tensor image analysis along the perivascular space (DTI-ALPS), and enlarged perivascular spaces (EPVS).MethodsFifty-one PD patients and fifty healthy control (HC) were included. Based on the Hoehn-Yahr scale, the PD group was divided into early-stage and medium-to late-stage. All PD patients were scored using the Unified PD Rating Scale (UPDRS). We assessed the DTI-ALPS indices in the bilateral hemispheres and EPVS numbers in bilateral centrum semiovale (CSO), basal ganglia (BG), and midbrain.ResultsThe DTI-ALPS indices were significantly lower bilaterally in PD patients than in the HC group, and EPVS numbers in any of the bilateral CSO, BG, and midbrain were significantly higher, especially for the medium- to late-stage group and the BG region. In PD patients, the DTI-ALPS index was significantly negatively correlated with age, while the BG-EPVS numbers were significantly positively correlated with age. Furthermore, the DTI-ALPS index was negatively correlated with UPDRS II and III scores, while the BG-EPVS numbers were positively correlated with UPDRS II and III scores. Similarly, the correlation was more pronounced in the medium- to late-stage group.ConclusionThe DTI-ALPS index and EPVS numbers (especially in the BG region) are closely related to age and PD progression and can serve as non-invasive assessments for glymphatic dysfunction and its interventions in clinical studies.

生理学是西医院校医学生的一门专业基础课,生理学实验是生理学教学的重要组成部分.在当下培养复合型医学人才的导向下,文章认为有必要在生理学实验教学中适当引入中医药实验和实操,这不仅有利于医学生从中西医两个不同角度来探索生命活动规律,也有利于在专业课学习的同时进行思政教育,培养大学生的民族文化自信.在生理学实验课上,教师通过人体实操和动物实验的方式,让学生见证中医药的真实疗效,认识到实践在探索生命活动规律过程中的重要性以及中医在方法论上的独特之处,文章也对可能遇到的问题进行了分析.

The glymphatic system contributes to the clearance of amyloid-β from the brain and is disrupted in Alzheimer's disease. However, whether the system is involved in the removal of α-synuclein (α-syn) and whether it is suppressed in Parkinson's disease (PD) remain largely unknown. In mice receiving the intranigral injection of recombinant human α-syn, we found that the glymphatic suppression via aquaporin-4 (AQP4) gene deletion or acetazolamide treatment reduced the clearance of injected α-syn from the brain. In mice overexpressing the human A53T-α-syn, we revealed that AQP4 deficiency accelerated the accumulation of α-syn, facilitated the loss of dopaminergic neurons, and accelerated PD-like symptoms. We also found that the overexpression of A53T-α-syn reduced the expression/polarization of AQP4 and suppressed the glymphatic activity of mice. The study demonstrates a close interaction between the AQP4-mediated glymphatic system and parenchymal α-syn, indicating that restoring the glymphatic activity is a potential therapeutic target to delay PD progression.

目前在国内大多数西医院校的生理学教学过程中,很少提及中医学关于人体生理活动的认识.在西医院校的生理学教学中适当引入中医知识,不仅有利于医学生中西互参,更全面的理解生命活动规律,也有利于在专业课学习的同时进行思想政治教育,培养当代大学生的民族自信和文化自信.根据实践经验,提出了一些具体的实施方案,包括在理论课上要着重指出中医的科学性及中西医的不同之处,在实验课上需要增加中医实操练习,也对教学实践中可能遇到的问题进行了分析.

Accumulating evidence indicates that the glymphatic system has a critical role in maintaining brain homeostasis. However, the detailed anatomy of the glymphatic pathway is not well understood, mostly due to a lack of high spatial resolution 3D visualization. In this study, a fluorescence micro-optical sectioning tomography (fMOST) was used to characterize the glymphatic architecture in the mouse brain. At 30 and 120 min after intracisternal infusion with fluorescent dextran (Dex-3), lectin was injected to stain the cerebral vasculature. Using fMOST, a high-resolution 3D dataset of the brain-wide distribution of Dex-3 was acquired. Combined with fluorescence microscopy and microplate array, the heterogeneous glymphatic flow and the preferential irrigated regions were identified. These cerebral regions containing large-caliber penetrating arteries and/or adjacent to the subarachnoid space had more robust CSF flow compared to other regions. Moreover, the major glymphatic vessels for CSF influx and fluid efflux in the entire brain were shown in 3D. This study demonstrates the regional heterogeneity in the glymphatic system and provides an anatomical resource for further investigation of the glymphatic function.

Abstract Aims Gao-Zi-Yao has long been a unique way for treating various diseases. The present study is to explore the effect of Gao-Zi-Yao on learning and memory function in old spontaneous hypertensive rats (SHR) and its possible mechanism. Method Male old SHR were received different doses of Gao-Zi-Yao for 4 weeks. Systolic blood pressure (SBP) and heart rate were monitored. Serum levels of nitric oxide (NO), interleukin (IL)-1β, IL-2, and tumor necrotic factor (TNF)-α were measured. Morris water maze was performed to test the learning and memory function of the rats. Number of neurons in hippocampus was counted by Nissl staining. Western blot was applied to detect the expressions of learning and memory function related proteins, N-methyl-d-aspartate receptor 2B (NMDAR 2B), glutamate receptor 1 (GluR1), phosphorylated-calmodulin-dependent protein kinase II (p-CaMK II), and phosphorylated-cAMP responsive element-binding protein (p-CREB) in rat hippocampus. Results Data showed that Gao-Zi-Yao reduced SBP in old SHR, elevated NO level, and suppressed levels of IL-1β, IL-2, TNF-α. The results of Morris water maze experiment showed that Gao-Zi-Yao dose-dependently improved learning and memory function. Number of neurons in the hippocampal dentate gyrus (DG) region of the old SHR was increased by Gao-Zi-Yao treatment. In addition, Gao-Zi-Yao elevated the protein expressions of NMDAR 2B, GluR1, p-CaMK II, and p-CREB in hippocampus. Conclusion Gao-Zi-Yao decreases SBP and improves the learning and memory function of the old SHR by regulation of oxidative stress, inflammatory factors and neuron number in hippocampal DG area and the expression of learning and memory function related proteins.

Background: Signal transduction of Angiotensin II (Ang II) induced autophagy and its role in Ang II-induced dysfunction of HUVECs are still unclear. Methods: HUVECs are stimulated with different doses of Ang II (10-9-10-5 mol/L) for different time (6-48 hours). Autophagy-related protein markers: LC3, Beclin-1 and SQSTM1/p62 are measured by western blot. Results: Incubation with Ang II increases autophagic flux (Beclin-1, autophagosomes formation, and degradation of SQSTM1/p62, LC3-I). Increased autophagic levels are inhibited by pretreatment with Ang II type 1 receptor (AT1) blocker (Candesartan), NADPH Oxidase inhibitor (apocycin), mitochondrial KATP channels inhibitor (5-hydroxydecanoate, 5HD). 3-Methyladenine (inhibitors of autophagy) and rapamycin (activator of autophagy) respectively inhibits or activates Ang II-induced autophagy levels. Ang II decreases phosphorylation of endothelial nitric oxide synthase (eNOS) and NO production in HUVECs. L-NAME (NOS inhibitor) totally mimics the actions of Ang II on eNOS, NO production and autophagy levels. Rapamycin further decreases NO production combined with Ang II. Silence Atg5 completely reverses Ang II-activated autophagy levels. Conclusions: Our results demonstrate that Ang II stimulation increases autophagy levels via AT1 receptor, NADPH oxidase, mitochondrial KATP channel, eNOS, Atg5 signal pathway in HUVECs, and activation of autophagy contributes to Ang II induced dysfunction of HUVECs.

Background: Oral herb medicine paste (Gao-Zi-Yao) has long been a unique way for treating various diseases. The present study is to explore the effect of Gao-Zi-Yao on learning and memory function in elderly spontaneous hypertensive rats (SHR) and its possible mechanism. Methods: Male elderly SHR were received different doses of Gao-Zi-Yao for 4 weeks. Systolic blood pressure (SBP) and heart rate were monitored. Morris water maze was performed to test the learning and memory function of the rats. Number of neurons in hippocampus was counted by Nissl staining. Western blot was applied to detect the expressions of learning and memory function related proteins, N-methyl-d-aspartate receptor 2B (NMDAR 2B), glutamate receptor 1 (GluR1), phosphorylated-calmodulin-dependent protein kinase II (p-CaMK II), and phosphorylated-cAMP responsive element-binding protein (p-CREB) in rat hippocampus.Findings: Data showed that Gao-Zi-Yao reduced SBP in elderly SHR. The results of Morris water maze experiment showed that Gao-Zi-Yao dose-dependently improved learning and memory function. Number of neurons in the hippocampal dentate gyrus (DG) region of the elderly SHR was increased by Gao-Zi-Yao treatment. In addition, Gao-Zi-Yao elevated the protein expressions of NMDAR 2B, GluR1, p-CaMK II, and p-CREB in hippocampus.Interpretation: Gao-Zi-Yao decreases SBP and improves the learning and memory function of the elderly SHR by regulation of neuron number in hippocampal DG area and the expressions of learning and memory function related proteins.Funding Statement: This work was supported by the National Natural Science Foundation of China (81970422), Suzhou Municipal Science and Technology Bureau (SS201745, GSWS2019022, SYSD2020210), and 5th 333 Project of Jiangsu Province.Declaration of Interests: The authors stated 'not applicable.'Ethics Approval Statement: The experiments were performed in according with the National Institutes of Health Guidelines for the Use of Laboratory Animals (NIH, publication number 85-23, revised 1996.), which were approved by and performed according to guidelines for the care and use of animals established by Soochow University. All the herbs and other materials used in the preparation of Gao-Zi Yao were approved by National Health Commission of the People’s Republic of China.

BackgroundPulmonary hypertension (PH) remains a prevalent disease globally. Sodium tanshinone II sulfonate A (STS) has been used in clinical treatment of PH.AimsThe aim of the present study was to investigate the effect of sodium STS treatment on hypoxia-induced PH and related mechanisms.MethodsMale Sprague-Dawley rats were housed in a hypoxic chamber with an oxygen concentration of 10 ± 1% for 8 h a day over 21 days. Rats were treated with either STS (low-dose: 10 mg/kg or high-dose: 30 mg/kg) or LY294002 (which is an inhibitor of PI3K). Pulmonary arterial pressure (PAP) was measured, right ventricular hypertrophy parameters were monitored, lung edema parameters were measured, and pathological changes were observed by hematoxylin-eosin (HE) staining. Protein expressions of apoptosis, and PI3K/AKT/mTOR/autophagy pathways in rat lung tissue were examined by western blot. Levels of the pro-inflammatory factors IL-6, IL-8, TNF-α in lung tissues of rats were measured using an enzyme linked immunosorbent assay (ELISA).ResultsResults of our study demonstrate that persistent exposure to hypoxic conditions increased PAP, right ventricular hypertrophy, lung edema, parameters of lung vascular proliferation and decreased the ratio of Bax/Bcl-2. Furthermore, hypoxic conditions activated the PI3K/Akt/mTOR pathway, inhibited autophagy, and elevated abundance of inflammatory factors in rat lung tissue. Treatment with STS resulted in a dose-dependent decrease in PAP, right ventricular hypertrophy, lung edema, lung vascular proliferation and reversed hypoxia induced lung tissue protein expression and pro-inflammatory factors in rat lung tissue. In addition, hypoxia-induced increases in PAP, cardiac hypertrophy, and lung expression of the proteins PI3K/Akt/mTOR/autophagy pathway were partially reversed by treatment with LY294002.ConclusionsSTS alleviates hypoxia-induced PH by promoting apoptosis, inhibiting PI3K/AKT/mTOR pathway, up-regulating autophagy, and inhibiting inflammatory responses.

Following intrathecal injection of fluorescent tracers,ex vivoimaging of brain vibratome slices has been widely used to study the glymphatic system in the rodent brain. Tracer penetration into the brain is usually quantified by image-processing, even though this approach requires much time and manual operation. Here, we illustrate a simple protocol for the quantitative determination of glymphatic activity using spectrophotofluorometry. At specific time-points following intracisternal or intrastriatal injection of fluorescent tracers, certain brain regions and the spinal cord were harvested and tracers were extracted from the tissue. The intensity of tracers was analyzed spectrophotometrically and their concentrations were quantified from standard curves. Using this approach, the regional and dynamic delivery of subarachnoid CSF tracers into the brain parenchyma was assessed, and the clearance of tracers from the brain was also determined. Furthermore, the impairment of glymphatic influx in the brains of old mice was confirmed using our approach. Our method is more accurate and efficient than the imaging approach in terms of the quantitative determination of glymphatic activity, and this will be useful in preclinical studies.

Aims The arcuate nucleus is a vital brain region for coursing of pain command. G protein-coupled kinase 6 (GRK6) accommodates signaling through G protein-coupled receptors. Studies have demonstrated that GRK6 is involved in inflammatory pain and neuropathic pain. The present study was designed to explore the role and the underlying mechanism of GRK6 in arcuate nucleus of chronic visceral pain. Methods Chronic visceral pain of rats was induced by neonatal maternal deprivation and evaluated by monitoring the threshold of colorectal distension. Western blotting, immunofluorescence, real-time quantitative polymerase chain reaction techniques, and Nissl staining were employed to determine the expression and mutual effect of GRK6 with nuclear factor κB (NF-κB). Results Expression of GRK6 in arcuate nucleus was significantly reduced in neonatal maternal deprivation rats when compared with control rats. GRK6 was mainly expressed in arcuate nucleus neurons, but not in astrocytes, and a little in microglial cells. Neonatal maternal deprivation reduced the percentage of GRK6-positive neurons of arcuate nucleus. Overexpression of GRK6 by Lentiviral injection into arcuate nucleus reversed chronic visceral pain in neonatal maternal deprivation rats. Furthermore, the expression of NF-κB in arcuate nucleus was markedly upregulated in neonatal maternal deprivation rats. NF-κB selective inhibitor pyrrolidine dithiocarbamate suppressed chronic visceral pain in neonatal maternal deprivation rats. GRK6 and NF-κB were expressed in the arcuate nucleus neurons. Importantly, overexpression of GRK6 reversed NF-κB expression at the protein level. In contrast, injection of pyrrolidine dithiocarbamate once daily for seven consecutive days did not alter GRK6 expression in arcuate nucleus of neonatal maternal deprivation rats. Conclusions Present data suggest that GRK6 might be a pivotal molecule participated in the central mechanisms of chronic visceral pain, which might be mediated by inhibiting NF-κB signal pathway. Overexpression of GRK6 possibly represents a potential strategy for therapy of chronic visceral pain.

The glymphatic system has recently been proposed to function as a brain-wide macroscopic system for the clearance of potentially harmful molecules, such as amyloid beta (e.g., Aβ), from the brain parenchyma. Previous literatures have established that the glymphatic function is dramatically suppressed by aging, traumatic brain injury, and some diseases. However, the effect of chronic stress on the glymphatic function and its underlying mechanism remains largely unknown.

The glymphatic system is a cerebrospinal fluid-interstitial fluid exchange system dependent on the water channel aquaporin-4 polarized on astrocyte endfeet, which is proposed to account for the clearance of abnormal proteins (e.g. β-amyloid) and metabolites (e.g. lactate) from the brain. Accumulating studies have revealed that glymphatic activity during sleep and general anesthesia is dramatically enhanced, while its function is significantly damaged during aging, traumatic brain injury, Alzheimer's disease, stroke, and diabetes. The glymphatic hypothesis is a breakthrough in the field of neuroscience recently, which would considerably enhance our comprehension on the cerebrospinal fluid circulation and its role in the maintenance of brain homeostasis. In this review, we briefly introduced the conceptualization of glymphatic system, summarized the recent progresses, and prospected its future investigation and potential clinical application.

AimsAccumulating evidence supports that cerebrospinal fluid (CSF) in the subarachnoid space (SAS) could reenter the brain parenchyma via the glymphatic influx. The present study was designed to characterize the detailed pathway of subarachnoid CSF influx by using a novel CSF tracer.Main methodsFluorescently conjugated cadaverine (A488-ca), for the first time, was employed to investigate CSF movement in the brain. Following intracisternal infusion of CSF tracers, mice brain was sliced and prepared for fluorescence imaging. Some brain sections were immunostained in order to observe tracer distribution and cellular uptake.Key findingsA488-ca moved into the brain parenchyma rapidly, and the influx was time and region dependent. A488-ca entered the mice brain more readily and spread more widely than another commonly used CSF tracer-fluorescently conjugated ovalbumin (OA-45). Furthermore, A488-ca could enter the brain parenchyma either along the paravascular space or across the pial surface. Suppression of glymphatic transport by administration with acetazolamide strikingly reduced the influx of A488-ca. More importantly, relative to OA-45 largely remained in the extracellular space, A488-ca exhibited obvious cellular uptake by astrocytes surrounding the blood vessels and neurons in the cerebral cortex.SignificanceSubarachnoid CSF could flow into the brain parenchyma via the glymphatic influx, in which the transcellular pathway was faithfully traced by intracisternal infusion with fluorescently conjugated cadaverine. These observations extend our comprehension on the glymphatic influx pathway.

AIMS:The aim of the present study was to assess how genetically increased Sarcoplasmic reticulum Ca2+-ATPase (Serca2a) expression affects cardiac injury after Ischemia/Reperfusion (I/R) exposure and the related mechanisms involved.METHODS AND RESULTS:Rats were subjected to Left Anterior Descending coronary artery (LAD) occlusion for 30 min followed by a 24-hour reperfusion. Cardiac function analysis revealed that cardiac function dramatically improved in Serca2a transgenic rats, (Serca2aTG) rats, compared to Wild Type (WT) rats. Serca2aTG rats developed a significantly smaller myocardial infarction size compared to those in WT group. The expression of the Bcl-2 was lower in Serca2aTG rats compared with WT rats; but, Bcl-2 expression was markedly increased in Serca2aTG rats compared with WT after I/R. In addition, Bax was markedly downregulated in Serca2aTG rats compared to WT group after I/R. Meanwhile, autophagy marker LC-3B was increased in Serca2aTG group, and p62 was only increased in WT group but not in Serca2aTG group in response to I/R. Electron microscope observation confirmed that there were more autophagosomes in Serca2aTG group than in WT rats after I/R.CONCLUSION:our findings demonstrated that the overexpression of Serca2a plays an important role in myocardial protection from I/R injury and postischemic functional recovery, which may be via antinecrotic, anti-apoptotic and pro-autophagy signal pathways. Our research provides solid basic data and new perspective on clinical treatment in heart failure patients with long-term over-expression of Serca2a.