Disease Stage-Associated Alterations in Learning and Memory through the Electroacupuncture Modulation of the Cortical Microglial M1/M2 Polarization in Mice with Alzheimer's Disease

Signaling pathways in the treatment of Alzheimer's disease with acupuncture: a narrative review

BACKGROUND

To date, there is no effective treatment for Alzheimer's disease (AD), a progressive neurodegenerative disorder that is increasing in prevalence worldwide. The objective of this review was to summarize the core targets and signaling pathways involved in acupuncture treatment for AD.

METHODS

We reviewed numerous signaling pathways, including mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase-protein kinase B (PI3 K/Akt), adenosine monophosphate-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), nuclear factor (NF)-kB, p53, Wnt, nitric oxide (NO), Janus kinase / signal transducer and activator of transcription (JAK/ STAT), RhoA/ROCK (Rho-associated protein kinase) and Ca2+/ calmodulin-dependent protein kinase II (CaMKII) / cyclic adenosine monophosphate-response element-binding protein (CREB). The relevant data were obtained from PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI) and Wanfang databases.

RESULTS

In summary, the effects of acupuncture are mediated by multiple targets and pathways. Furthermore, acupuncture can improve pathological changes associated with AD (such as abnormal deposition of amyloid (A)β, tau hyperphosphorylation, synaptic dysfunction and neuronal apoptosis) through multiple signaling pathways.

CONCLUSION

Overall, our findings provide a basis for future research into the effects of acupuncture on AD.

A review on traditional Chinese medicine natural products and acupuncture intervention for Alzheimer's disease based on the neuroinflammatory

Alzheimer's disease (AD) is a neurodegenerative disease with insidious onset and progressive development. It is clinically characterized by cognitive impairment, memory impairment and behavioral change. Chinese herbal medicine and acupuncture are important components of traditional Chinese medicine (TCM), and are commonly used in clinical treatment of AD. This paper systematically summarizes the research progress of traditional Chinese medicine natural products and acupuncture treatment of AD, which combined with existing clinical and preclinical evidence, based on a comprehensive review of neuroinflammation, and discusses the efficacy and potential mechanisms of traditional Chinese medicine natural products and acupuncture treatment of AD. Resveratrol, curcumin, kaempferol and other Chinese herbal medicine components can significantly inhibit the neuroinflammation of AD in vivo and in vitro, and are candidates for the treatment of AD. Acupuncture can alleviate the memory and cognitive impairment of AD by improving neuroinflammation, synaptic plasticity, nerve cell apoptosis and reducing the production and aggregation of amyloid β protein (Aβ) in the brain. It has the characteristics of early, safe, effective and benign bidirectional adjustment. The purpose of this paper is to provide a basis for improving the clinical strategies of TCM for the treatment of AD.

Anti-inflammatory Action of BT75, a Novel RARα Agonist, in Cultured Microglia and in an Experimental Mouse Model of Alzheimer's Disease

BT75, a boron-containing retinoid, is a novel retinoic acid receptor (RAR)α agonist synthesized by our group. Previous studies indicated that activation of retinoic acid (RA) signaling may attenuate progression of Alzheimer's disease (AD). Presently, we aimed to examine the anti-inflammatory effect of BT75 and explore the possible mechanism using cultured cells and an AD mouse model. Pretreatment with BT75 (1-25 µM) suppressed the release of nitric oxide (NO) and IL-1β in the culture medium of mouse microglial SIM-A9 cells activated by LPS. BMS195614, an RARα antagonist, partially blocked the inhibition of NO production by BT75. Moreover, BT75 attenuated phospho-Akt and phospho-NF-κB p65 expression augmented by LPS. In addition, BT75 elevated arginase 1, IL-10, and CD206, and inhibited inducible nitric oxide synthase (iNOS) and IL-6 formation in LPS-treated SIM-A9 cells, suggesting the promotion of M1-M2 microglial phenotypic polarization. C57BL/6 mice were injected intracerebroventricularly (icv) with streptozotocin (STZ) (3 mg/kg) to provide an AD-like mouse model. BT75 (5 mg/kg) or the vehicle was intraperitoneally (ip) injected to icv-STZ mice once a day for 3 weeks. Immunohistochemical analyses indicated that GFAP-positive cells and rod or amoeboid-like Iba1-positive cells, which increased in the hippocampal fimbria of icv-STZ mice, were reduced by BT75 treatment. Western blot results showed that BT75 decreased levels of neuronal nitric oxide synthase (nNOS), GFAP, and phosphorylated Tau, and increased levels of synaptophysin in the hippocampus of icv-STZ mice. BT75 may attenuate neuroinflammation by affecting the Akt/NF-κB pathway and microglial M1-M2 polarization in LPS-stimulated SIM-A9 cells. BT75 also reduced AD-like pathology including glial activation in the icv-STZ mice. Thus, BT75 may be a promising anti-inflammatory and neuroprotective agent worthy of further AD studies.

The neuroprotective and neural circuit mechanisms of acupoint stimulation for cognitive impairment

Cognitive impairment is a prevalent neurological disorder that burdens families and the healthcare system. Current conventional therapies for cognitive impairment, such as cholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists, are unable to completely stop or reverse the progression of the disease. Also, these medicines may cause serious problems with the digestive system, cardiovascular system, and sleep. Clinically, stimulation of acupoints has the potential to ameliorate the common symptoms of a variety of cognitive disorders, such as memory deficit, language dysfunction, executive dysfunction, reduced ability to live independently, etc. There are common acupoint stimulation mechanisms for treating various types of cognitive impairment, but few systematic analyses of the underlying mechanisms in this domain have been performed. This study comprehensively reviewed the basic research from the last 20 years and found that acupoint stimulation can effectively improve the spatial learning and memory of animals. The common mechanism may be that acupoint stimulation protects hippocampal neurons by preventing apoptosis and scavenging toxic proteins. Additionally, acupoint stimulation has antioxidant and anti-inflammatory effects, promoting neural regeneration, regulating synaptic plasticity, and normalizing neural circuits by restoring brain functional activity and connectivity. Acupoint stimulation also inhibits the production of amyloid β-peptide and the phosphorylation of Tau protein, suggesting that it may protect neurons by promoting correct protein folding and regulating the degradation of toxic proteins via the autophagy-lysosomal pathway. However, the benefits of acupoint stimulation still need to be further explored in more high-quality studies in the future.

Effect of acupuncture on neuroinflammation in animal models of Alzheimer's disease: A preclinical systematic review and meta-analysis

Background

Despite neuroinflammation being an important component of the pathology of Alzheimer's disease (AD), effective therapies to alleviate neuroinflammation are still lacking. Many animal experiments in AD have found that acupuncture may ameliorate cognition by decreasing neuroinflammation and modulating cytokines, but its effects have not been systematically examined. We aimed to assess its efficacy on neuroinflammation in AD and to investigate the potential mechanisms.

Materials and methods

The following databases were searched from inception until 24 August 2022: Web of Science, EMBASE, PubMed, the Cochrane Library, and China National Knowledge Infrastructure. Animal studies that reported the efficacy of acupuncture on neuroinflammation in AD were included. The SYRCLE Robt was utilized to evaluate methodological quality. Stata 17 was utilized to conduct a meta-analysis of cytokine levels and the results of the Morris water maze.

Results

23 studies were included, with a total of 417 rats/mice. The overall quality of all included reports was medium. The results indicated that acupuncture significantly reduced the expressions of pro-inflammatory cytokines which included IL-1β [SMD = -3.50, 95% CI (-4.31, -2.69); I ² = 78.6%] (P < 0.05), TNF-α [SMD = -3.05, 95% CI (-3.86, -2.24); I ² = 69.6%] (P < 0.05), IL-6 [SMD = -3.22, 95% CI (-4.62, -1.81); I ² = 77.6%] and enhanced the expressions of anti-inflammatory cytokines including IL-4 [SMD = 2.77, 95% CI (1.95, 3.59); I ² = 33.9%] (P < 0.05), IL-10 [SMD = 1.84, 95% CI (1.20, 2.49); I ² = 41.0%] (P < 0.05) in an animal model of AD. Regarding the Morris water maze, compared to the control group, the acupuncture group showed a shorter escape latency [SMD = -2.23, 95% CI (-2.89, -1.57); I ² = 79.2%] (P < 0.05), longer duration in platform quadrant [SMD = 2.34, 95% CI (1.44, 3.23); I ² = 81.7%] (P < 0.05), and increased platform crossing number [SMD = 2.79, 95% CI (2.06, 3.53); I ² = 71.9%] (P < 0.05).

Conclusion

Acupuncture may reduce neuroinflammation in AD by modulating cytokine expression. This modulation significantly improved cognitive function in animal models of AD.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022354878.

Research progress on the immunomodulatory mechanism of acupuncture in tumor immune microenvironment

With the constantly deeper understanding of individualized precision therapy, immunotherapy is increasingly developed and personalized. The tumor immune microenvironment (TIME) mainly consists of infiltrating immune cells, neuroendocrine cells, extracellular matrix, lymphatic vessel network, etc. It is the internal environment basis for the survival and development of tumor cells. As a characteristic treatment of traditional Chinese medicine, acupuncture has shown potentially beneficial impacts on TIME. The currently available information demonstrated that acupuncture could regulate the state of immunosuppression through a range of pathways. An effective way to understand the mechanisms of action of acupuncture was to analyze the response following treatment of the immune system. This research reviewed the mechanisms of acupuncture regulating tumor immunological status based on innate and adaptive immunity.

Research status, hotspots and trends of acupuncture and moxibustion in the treatment of Alzheimer's disease: A bibliometric analysis

BACKGROUND

Acupuncture and moxibustion (AM) are utilized to treat Alzheimer's disease (AD). However, no bibliometric analysis has explored this issue. Thus, this study investigated the status, hotspots and trends of AM in the treatment of AD.

METHODS

CiteSpace and VOSviewer softwares were used to analyze the literature on the AM for AD in the Web of Science Core Collection database. We analyzed the data of countries/regions, institutions, journals, authors, keywords, and cited references.

RESULTS

After removing duplicates, 193 articles were retrieved. The number of publications on this topic has increased gradually. The most productive and collaborative country was China (143 documents), followed by South Korea (19). The top 3 active academic institutions were Beijing University of Chinese Medicine, Capital Medicine University, and Guangzhou University of Chinese Medicine. The most productive journal was Evidence-based Complementary and Alternative Medicine (13 documents), followed by the Frontiers in Aging Neuroscience (10), Medicine (10), and Neural Regeneration Research (10). The top 3 co-cited journals were Evidence-based Complementary and Alternative Medicine (156 citations), Acupuncture Electro-therapeutics Research (152), and Acupuncture in Medicine (146). The research hotspots in this domain are dementia, memory, hippocampus, mouse models, and Parkinson's disease. Major frontiers are comparing the therapeutic effects of acupuncture and donepezil and electroacupuncture at different frequencies in this field.

CONCLUSION

This bibliometric study identified relevant hotspots and trends in research on AM in the treatment of AD, which can provide researchers with key information in this domain and help further explore new research directions.

Cyanidin-3-O-Glucoside Regulates the M1/M2 Polarization of Microglia via PPARγ and Aβ42 Phagocytosis Through TREM2 in an Alzheimer's Disease Model

Microglial polarization plays an essential role in the progression and regression of neurodegenerative disorders. Cyanidin-3-O-glucoside (C3G), a dietary anthocyanin found in many fruits and vegetables, has been reported as an antioxidant, anti-inflammatory, and antitumor agent. However, there have been no reports on whether C3G can regulate the M1/M2 shift in an Alzheimer's disease model. We attempted to investigate the effects of C3G on M1/M2 polarization and the mechanism to regulate anti-inflammation and phagocytosis, both in vitro and in vivo. HMC3 cells were treated with β-amyloid (Aβ42) in the presence or absence of 50 μM C3G for different time intervals, and APPswe/PS1ΔE9 mice were orally administered 30 mg/kg/day of C3G for 38 weeks. The in vitro data revealed that C3G could shift the M1 phenotype of microglia to M2 by reducing the expression of M1-specific markers (CD86 and CD80), inflammatory cytokines (IL-Iβ, IL-6, TNF-α), reactive oxygen species, and enhancing the expression of M2-specific markers (CD206 and CD163). The APPswe/PS1ΔE9 mice results were consistent with the in vitro data, indicating a significant reduction in inflammatory cytokines and higher expression of M2-specific markers such as CD206 and Arg1 in C3G-treated Alzheimer's disease model mice. Additionally, C3G was found to upregulate PPARγ expression levels both in vitro and in vivo, whereas a PPARγ antagonist (GW9662) was found to block C3G-mediated effects in vitro. In this study, we confirmed that C3G could regulate microglial polarization by activating PPARγ and eliminating accumulated β-amyloid by enhancing Aβ42 phagocytosis through the upregulation of TREM2.

Modulation of entorhinal cortex–hippocampus connectivity and recognition memory following electroacupuncture on 3×Tg-AD model: Evidence from multimodal MRI and electrophysiological recordings

Memory loss and aberrant neuronal network activity are part of the earliest hallmarks of Alzheimer’s disease (AD). Electroacupuncture (EA) has been recognized as a cognitive stimulation for its effects on memory disorder, but whether different brain regions or neural circuits contribute to memory recovery in AD remains unknown. Here, we found that memory deficit was ameliorated in 3×Tg-AD mice with EA-treatment, as shown by the increased number of exploring and time spent in the novel object. In addition, reduced locomotor activity was observed in 3×Tg-AD mice, but no significant alteration was seen in the EA-treated mice. Based on the functional magnetic resonance imaging, the regional spontaneous activity alterations of 3×Tg-AD were mainly concentrated in the accumbens nucleus, auditory cortex, caudate putamen, entorhinal cortex (EC), hippocampus, insular cortex, subiculum, temporal cortex, visual cortex, and so on. While EA-treatment prevented the chaos of brain activity in parts of the above regions, such as the auditory cortex, EC, hippocampus, subiculum, and temporal cortex. And then we used the whole-cell voltage-clamp recording to reveal the neurotransmission in the hippocampus, and found that EA-treatment reversed the synaptic spontaneous release. Since the hippocampus receives most of the projections of the EC, the hippocampus-EC circuit is one of the neural circuits related to memory impairment. We further applied diffusion tensor imaging (DTI) tracking and functional connectivity, and found that hypo-connected between the hippocampus and EC with EA-treatment. These data indicate that the hippocampus–EC connectivity is responsible for the recognition memory deficit in the AD mice with EA-treatment, and provide novel insight into potential therapies for memory loss in AD.

A Review on Characteristics of Experimental Research on Acupuncture Treatment for Alzheimer's Disease: Study Design

Background

This review aims to systematically summarize and analyze recent high-quality animal research results about the use of acupuncture in Alzheimer's disease (AD) patients. This information will be useful in providing a reference for future experimental research and an experimental basis for the clinical use of acupuncture in the treatment of AD.

Methods

We utilized and referenced various electronic libraries from their inception to November 2021. Relevant information was reviewed and information such as the journal names, publication records, animal model selections and preparations, intervention measures, acupoint selections, detection methods, and detection indicators was extracted. Results. A total of 75 eligible studies were selected for additional review. Male SAMP8 mice, APP/PS1 double transgenic mice, Sprague-Dawley (SD) rats, and Wistar rats were the four commonly used animal strains in the experiments. The animals were categorized as transgenic and surgical mouse models. Experimental interventions included manual acupuncture (MA), Electro-acupuncture (EA), Moxibustion, and EA combined with Moxibustion. A retention time of 20 min was the optimal timing for experimental studies, with 14 sessions chosen as the most common treatment time. EA was the most prescribed acupuncture treatment type with continuous wave, 2 Hz frequency, and 1 mA electric current selected as frequently used parameters. A total of 78 acupoint prescriptions were analyzed involving 21 acupoints. The top 3 combinations of common acupoints were GV20 ⟶ EX-HN3, GV20 ⟶ BL23, and GV20 ⟶ GV26. A total of 39 articles had positive drug control groups, sham acupuncture, and/or nonacupoint control groups. Furthermore, 10 types of behavioral tests, 29 detection methods, 178 evaluation indicators, and 18 tissue samples were included in the analysis.

Conclusions

By collating these high-quality research studies systematically and comprehensively, acupuncture was found to be a viable and effective treatment in AD animal models. In addition, when designing experiments, researchers could refer to the detailed data provided here to make better schemes and maybe conduct more investigations in unresearched areas.

The Effects of Moxibustion on Learning and Memory and m6A RNA Methylation in APP/PS1 Mice

Objectives

To study whether moxibustion can improve the learning and memory ability of APP/PS1 mice by reducing the pathological products Aβ and Tau protein via decreasing N6-methyladenosine (m6A).

Methods

APP/PS1 mice were randomly divided into model group (APP/PS1) and moxibustion group (APP/PS1+Mox). C57BL/6J mice were used as a control group (Control). Learning and memory abilities were assessed by the Morris water maze. Aβ, Tau, phosphorylated Tau (p-Tau), and YTHDF1 proteins were detected in the mouse cortex and hippocampus by immunofluorescence and western blot. Altered m6A expression levels in hippocampal and cortical tissues were measured with the m6A RNA methylation quantification assay kit. RNA transcript levels of YTHDF1, METTL3, and FTO in the hippocampus and cortex were measured by q-PCR.

Results

Moxibustion shortened the escape latency, increased the number of platform crossings, and increased the percentage of swimming time in the target quadrant of APP/PS1 mice. Meanwhile, moxibustion reduced the levels of Aβ, Tau, and p-Tau proteins both in the hippocampal and cortical regions of APP/PS1 mice. In addition, the total amount of m6A in the hippocampal and cortical regions of APP/PS1 mice was significantly reduced after moxibustion. The expression of YTHDF1 in the hippocampal region of APP/PS1 mice increased and that in the cortical region decreased after moxibustion treatment.

Conclusion

Moxibustion improves the learning and memory abilities and reduces the deposition of Aβ and Tau protein pathological products in APP/PS1 mice. This may be related to the fact that moxibustion reduces the total amount of m6A and inhibits its binding enzyme YTHDF1 in the hippocampus and cortex of APP/PS1 mice.

Electro-Acupuncture Improve the Early Pattern Separation in Alzheimer’s Disease Mice via Basal Forebrain-Hippocampus Cholinergic Neural Circuit

Objectives

To explore the effect of electro-acupuncture (EA) treatment on pattern separation and investigate the neural circuit mechanism involved in five familial mutations (5 × FAD) mice.

Methods

Five familial mutations mice were treated with EA at Baihui (DU20) and Shenting (DU24) acupoints for 30 min each, lasting for 4 weeks. Cognitive-behavioral tests were performed to evaluate the effects of EA treatment on cognitive functions. ¹H-MRS, Nissl staining, immunohistochemistry, and immunofluorescence were performed to examine the cholinergic system alteration. Thioflavin S staining and 6E10 immunofluorescence were performed to detect the amyloid-β (Aβ). Furthermore, hM4Di designer receptors exclusively activated by designer drugs (DREADDs) virus and long-term clozapine-N-oxide injection were used to inhibit the medial septal and vertical limb of the diagonal band and dentate gyrus (MS/VDB-DG) cholinergic neural circuit. Cognitive-behavioral tests and immunofluorescence were performed to investigate the cholinergic neural circuit mechanism of EA treatment improving cognition in 5 × FAD mice.

Results

Electro-acupuncture treatment significantly improved spatial recognition memory and pattern separation impairment, regulated cholinergic system via reduction neuron loss, upregulation of choline/creatine, choline acetyltransferase, vesicular acetylcholine transporter, and downregulation of enzyme acetylcholinesterase in 5 × FAD mice. Aβ deposition was reduced after EA treatment. Subsequently, the monosynaptic hM4Di DREADDs virus tracing and inhibiting strategy showed that EA treatment activates the MS/VDB-DG cholinergic neural circuit to improve the early pattern separation. In addition, EA treatment activates this circuit to upregulating M1 receptors positive cells and promoting hippocampal neurogenesis in the dentate gyrus (DG).

Conclusion

Electro-acupuncture could improve the early pattern separation impairment by activating the MS/VDB-DG cholinergic neural circuit in 5 × FAD mice, which was related to the regulation of the cholinergic system and the promotion of neurogenesis by EA treatment.

Palmitic Acid and Oleic Acid Differently Modulate TLR2-Mediated Inflammatory Responses in Microglia and Macrophages

The relationship between systemic immunity and neuroinflammation is widely recognised. Infiltration of peripheral immune cells to the CNS during certain chronic inflammatory states contributes significantly to neuropathology. Obesity and its co-morbidities are primary risk factors for neuroinflammatory and neurodegenerative conditions, including Alzheimer’s disease (AD). Dietary fats are among the most proinflammatory components of the obesogenic diet and play a prominent role in the low-grade systemic inflammation associated with the obese state. Saturated fatty acid (SFA) is largely implicated in the negative consequences of obesity, while the health benefits of monounsaturated fatty acid (MUFA) are widely acknowledged. The current study sought to explore whether SFA and MUFA differently modulate inflammatory responses in the brain, compared with peripheral immune cells. Moreover, we assessed the neuroinflammatory impact of high-fat-induced obesity and hypothesised that a MUFA-rich diet might mitigate inflammation despite obesogenic conditions. Toll-like receptor (TLR)2 mediates the inflammation associated with both obesity and AD. Using the TLR2 agonist lipoteichoic acid (LTA), we report that pre-exposure to either palmitic acid (PA) or oleic acid (OA) attenuated cytokine secretion from microglia, but heightened sensitivity to nitric oxide (NO) production. The reduction in cytokine secretion was mirrored in LTA-stimulated macrophages following exposure to PA only, while effects on NO were restricted to OA, highlighting important cell-specific differences. An obesogenic diet over 12 weeks did not induce prominent inflammatory changes in either cortex or hippocampus, irrespective of fat composition. However, we reveal a clear disparity in the effects of MUFA under obesogenic and non-obesogenic conditions.

Acupuncture therapy for Alzheimer's disease: The effectiveness and potential mechanisms

Alzheimer's disease (AD) is a common neurodegenerative disease that accounts for approximately 70% of dementia. Following the global escalation of the aging process, the morbidity of AD is increasing rapidly. The current treatment for AD is mainly limited to medications, such as acetylcholinesterase inhibitors. However, the efficacy of acetylcholinesterase inhibitors in improving memory and cognitive functions is not satisfactory. It is a challenge to find an effective alternative therapy for ameliorating AD symptoms. As an important therapeutic technique in traditional Chinese medicine, acupuncture has been proved effective in treating many neurologic diseases including AD. The efficacy of acupuncture is also acknowledged by the National Institutes of Health of the United States. Here, we summarized the effectiveness of acupuncture for treating AD. Especially, the role of acupuncture at certain acupuncture points in modulating the brain function through meridians activity based on Chinese meridian theory is discussed. How acupuncture at a certain acupoint can improve AD symptoms is also described. Furthermore, the possible molecular mechanisms of acupuncture for AD are reviewed, and the role of acupuncture in modulating signaling molecules in neural protection and homeostasis is highlighted. This study may help to understand the theoretical basis and potential molecular mechanisms of acupuncture therapy for AD.

Electroacupuncture Improves Clearance of Amyloid-β through the Glymphatic System in the SAMP8 Mouse Model of Alzheimer's Disease

Background

Memory loss and cognitive impairment characterize the neurodegenerative disorder, Alzheimer's disease (AD). Amyloid-β (Aβ) is the key factor that triggers the course of AD, and reducing the deposition of Aβ in the brain has been considered as a potential target for the treatment of AD. In clinical and animal studies, electroacupuncture (EA) has been shown to be an effective treatment for AD. In recent years, substantial evidence has accumulated suggesting the important role of the glymphatic system in Aβ clearance.

Objective

The purpose of this study was to explore whether EA modifies the accumulation of Aβ through the glymphatic system and may thus be applied to alleviate cognitive impairments.

Methods

Seven-month-old SAMP8 mice were randomized into a control group (Pc) and an electroacupuncture group (Pe). Age-matched SAMR1 mice were used as normal controls (Rc). Mice in the Pe group were stimulated on Baihui (GV20) and Yintang (GV29) for 10 min and then pricked at Shuigou (GV26) for ten times. EA treatment lasted for 8 weeks. In each week, EA would be applied once a day for the first five consecutive days and ceased at the remaining two days. After EA treatment, Morris water maze (MWM) test was used to evaluate the cognitive function; HE and Nissl staining was performed to observe the brain histomorphology; ELISA, contrast-enhanced MRI, and immunofluorescence were applied to explore the mechanisms underlying EA effects from Aβ accumulation, glymphatic system function, reactivity of astrocytes, and AQP4 polarization, respectively.

Results

This EA regime could improve cognition and alleviate neuropathological damage to brain tissue. And EA treatment might reduce Aβ accumulation, enhance paravascular influx in the glymphatic system, inhibit the reactivity of astrocytes, and improve AQP4 polarity.

Conclusion

EA treatment might reduce Aβ accumulation from the brain via improving clearance performance of the glymphatic system and thereby alleviating cognitive impairment.

Dietary Spray-Dried Porcine Plasma Reduces Neuropathological Alzheimer's Disease Hallmarks in SAMP8 Mice

Alzheimer's disease (AD) is characterized by the aberrant processing of amyloid precursor protein (APP) and the accumulation of hyperphosphorylated tau, both of which are accompanied by neuroinflammation. Dietary supplementation with spray-dried porcine plasma (SDP) has anti-inflammatory effects in inflammation models. We investigated whether dietary supplementation with SDP prevents the neuropathological features of AD. The experiments were performed in 2- and 6-month-old SAMP8 mice fed a control diet, or a diet supplemented with 8% SDP, for 4 months. AD brain molecular markers were determined by Western blot and real-time PCR. Senescent mice showed reduced levels of p-GSK3β (Ser9) and an increase in p-CDK5, p-tau (Ser396), sAPPβ, and the concentration of Aβ40, (all p < 0.05). SDP prevented these effects of aging and reduced Bace1 levels (all p < 0.05). Senescence increased the expression of Mme1 and Ide1 and pro-inflammatory cytokines (Il-17 and Il-18; all p < 0.05); these changes were prevented by SDP supplementation. Moreover, SDP increased Tgf-β expression (p < 0.05). Furthermore, in aged mice, the gene expression levels of the microglial activation markers Trem2, Ym1, and Arg1 were increased, and SDP prevented these increases (all p < 0.05). Thus, dietary SDP might delay AD onset by reducing its hallmarks in senescent mice.

Upregulation of Neuronal Cylindromatosis Expression is Essential for Electroacupuncture-Mediated Alleviation of Neuroinflammatory Injury by Regulating Microglial Polarization in Rats Subjected to Focal Cerebral Ischemia/Reperfusion

Background

Activated microglia are polarized into the M1 or M2 phenotype. We previously reported that electroacupuncture (EA) effectively prevented nuclear factor-κB (NF-κB) nuclear translocation and improved neuronal C-X-C motif 3 chemokine ligand 1 (CX3CL1) expression, repressing microglial activation by upregulating neuronal cylindromatosis (CYLD) expression in the periischemic cortex. However, the potential mechanisms are unclear. Therefore, we explored whether EA improved CYLD protein expression to regulate microglial polarization-mediated neuroinflammation and the potential mechanisms in an ischemic stroke model.

Methods

A middle cerebral artery occlusion/reperfusion (MCAO/R) model was established in male Sprague-Dawley (SD) rats. The rats were treated with EA at the Baihui, Hegu and Taichong acupoints once daily beginning 2 h after focal cerebral ischemia. CYLD gene interference was used to investigate the role of CYLD in microglial polarization. We used neurobehavioral evaluations and TTC staining to examine the neuroprotective effect of EA via CYLD upregulation. Immunofluorescence and RT-qPCR were used to measure NLRP3 activation, M1/M2 microglial activation, pro-/anti-inflammatory gene mRNA expression and crosstalk (CX3CL1/CX3CR1 axis) between neurons and microglia. Western blotting was used to assess the underlying molecular mechanism.

Results

CYLD inhibited M1 microglial activation and improved M2 microglial activation after 72 h of reperfusion. CYLD overexpression decreased the NLRP3 mRNA level. CYLD suppressed microglial overactivation by inhibiting NLRP3 activation. CYLD gene silencing partially weakened EA improvement of neurological function deficits and reduction of infarct volumes after 72 h reperfusion. In addition, EA inhibited M1-like phenotypic microglial activation and promoted M2-like phenotypic microglia through upregulating CYLD expression. Finally, EA-mediated modulation of the CX3CL1/CX3CR1 axis and NLRP3 inflammasome was reversed by CYLD gene silencing in the periischemic cortex.

Conclusion

EA-induced upregulation of neuronal CYLD expression plays anti-inflammatory and neuroprotective roles and regulates the interaction between neurons and microglia, thereby suppressing M1 and improving M2 microglial activation in the periischemic cortex.