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ObjectiveTo observe the possible mechanism of Xixin Decoction （洗心汤， XXD） in the prevention and treatment of Alzheimer 's disease（AD）. MethodsFifty rapid aging model mice （SAMP8） were randomly divided into model group， probiotic group， high-， moderate- and low-dose group of XXD， with 10 mice in each group. Another 10 homologous anti-rapid aging mice （SAMR1） were set as control group. After 10 weeks of feeding， the control group and the model group were given 10 ml·kg-1·d-1 of distilled water by gavage， while the probiotic group （0.39 g·kg-1·d-1）， the high-dose group of XXD （5.08 g·kg-1·d-1）， the moderate-dose group of XXD （2.54 g·kg-1·d-1）， and the low-dose group of XXD （1.27 g·kg-1·d-1） were given corresponding drugs or decoctions by gavage， once a day in all groups. After 10 weeks of intragastric administration， Morris water maze was used to detect the spatial learning and memory ability of mice in each group. HE staining was used to observe the pathological changes of hippocampal CA3 region and colon. The levels of β-amyloid 1-42 （Aβ1-42）， lipopolysaccharide （LPS）， serum amyloid A （SAA） and acetylcholine （ACH） in hippocampus and colon were detected by ELISA.The diversity of intestinal flora in mouse feces was detected by 16S rRNA sequencing. ResultsCompared to those in the control group， the levels of Aβ1-42，LPS， SAA increased， while the level of ACH decreased in the model group （P＜0.05 or P＜0.01）. Compared to those in the model group， the escape latency period of the probiotic group was significantly shortened on the 2nd and 5th days， while the escape latency period was shortened， and the residence time in the target platform quadrant increased in the high-dose XXD group during the 2nd to 5th days； the escape latency period was shortened significantly in the moderate-dose XXD group on the 5th day （P＜0.05 or P＜0.01）. Compared to those in the model group， the hippocampal neuron cells in the high- and moderate-dose XXD groups were arranged more closely， with decreased levels of SAA， Aβ1-42 and LPS， increased ACH level， Simpson and Shannon index （P＜0.05 or P＜0.01）； the arrangement of hippocampal neuron cells in the probiotic group and the low-dose XXD group was relatively loose； the proportions of Bacteroidetes and Prevotella were significantly reduced in the probiotic group and the high-dose XXD group， while that of Firmicutes and Lactobacillus significantly increased （P＜0.05 or P＜0.01）. Compared to those in the probiotic group and the high-dose XXD group， the number of goblet cells in the moderate-dose XXD group decreased， and the number of glands in the low-dose XXD group decreased with atrophy. The high-dose XXD group had decreased Aβ1-42 level in the hippocampus， increased ACH level in thehippocampus and colon tissue， and decreased SAA in the colon tissue than the moderate- and low-dose XXD groups （P＜0.05 or P＜0.01）； moreover， the SAA level in the hippocampus was significantly higher in the low-dose XXD group than the high- and moderate-dose groups （P＜0.01）. ConclusionXXD can improve the spatial learning and memory ability of SAMP8， reduce the production and deposition of LPS， SAA and Aβ1-42 in brain and intestine， and increase the content of ACH. The mechanism of its prevention and treatment of AD maybe related to regulating intestinal microecology， affecting flora diversity and improving inflammatory response.
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OBJECTIVE Alzheimer disease(AD)is a neurodegenerative disease with clinical hallmarks of pro-gressive cognitive impairment.Synergistic effects of Aβ-tau cascade reaction are tightly implicated in AD patholo-gy,and microglial NLRP3 inflammasome activation drives neuronal tauopathy through microglia and neurons cross-talk.However,the underlying mechanism of how Aβ medi-ates NLRP3 inflammasome remains unclear.Shab related potassium channel member 1(Kv2.1)as a voltage gated po-tassium channel widely distributed in the central nervous system and plays an important role in regulating the out-ward potassium flow in neurons and glial cells.In current work,we aimed to explore the underlying mechanism of Kv2.1 in regulating Aβ/NLRP3 inflammasome/tau axis by using a determined Kv2.1 inhibitor drofenine(Dfe).METHODS Cell-based assays including Western blot-ting and immunofluorescence staining against primary microglia or neurons were carried out to expound the role of Kv2.1 channel in NLRP3 inflammasome activa-tion and subsequent neuronal tau hyperphosphorylation.For animal studies,new object recognition,Y-maze and Morris water maze were performed to evaluate the ame-lioration of Kv2.1 inhibition through either Kv2.1 inhibitor Dfe treatment or adeno-associated virus AAV-ePHP-si-Kv2.1injectionon5×FADADmodel mice.Assays of histol-ogy and immunostaining of tissue sections and Western blotting of brain tissues were performed to verify the con-clusion of cellular assays.RESULTS We reported that oligomeric Aβ(o-Aβ)bound to microglial Kv2.1 and pro-moted Kv2.1-dependent potassium leakage to activate NLRP3 inflammasome through JNK/NF-κB pathway sub-sequently resulting in neuronal tauopathy.Treatment of either Kv2.1 inhibitor Dfe or AAV-ePHP-si-Kv2.1 for brain-specific Kv2.1 knockdown deprived o-A β of its capability in inducing microglial NLRP3 inflammasome activation and neuronal tau hyperphosphorylation,while improved the cognitive impairment of 5×FAD AD model mice.CONCLUSION Our results have highly addressed that Kv2.1 channel is required for o-Aβ driving NLRP3 inflammasome activation and neuronal tauopathy in AD model mice and highlighted that Kv2.1 inhibition is a prom-ising therapeutical strategy for AD and Dfe as a Kv2.1 inhibitor shows potential in the treatment of this disease.
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ObjectiveTo explore the effect of Qishengwan on ileal flora during its treatment of Alzheimer's disease （AD） under the guidance of the theory of "interior-exterior relationship between heart and small intestine". MethodThe AD model was established by bilateral intraventricular injection of β-amyloid 1-42 （Aβ1-42）. The rats were then randomly divided into the blank group， sham-operated group， model group， low-， medium-， and high-dose （5.6， 11.2，22.4 g·kg-1·d-1） Qishengwan groups， and donepezil （0.46 mg·kg-1·d-1） group. After medication for 28 successive days， the spatial memory ability of rats was observed in water maze test， and the levels of Aβ1-42， nuclear transcription factor-κB （NF-κB）， tumor necrosis factor-α （TNF-α）， and interleukin-6 （IL-6） in the hippocampus were analyzed by enzyme-linked immunosorbent assay （ELISA）. Additionally， the contents of the ileum were collected and subjected to 16SrRNA-sequencing analysis for figuring out the changes in ileal flora. ResultCompared with the blank group and sham-operated group， the model group exhibited significantly reduced stay time in the target quadrant and number of target quadrant and platform crossings （P<0.05， P<0.01） and elevated Aβ1-42 content in the hippocampus （P<0.01） and central inflammatory factors NF-κB， TNF-α， and IL-6 （P<0.05， P<0.01）. Compared with the model group， Qishengwan at each dose significantly alleviated the impaired spatial memory function （P<0.05， P<0.01）， improved the deposition of Aβ1-42 in the hippocampus of rats （P<0.05， P<0.01）， and reduced the expression of central nervous system inflammatory factors （P<0.05， P<0.01）， thus exerting a good therapeutic effect on AD rats. The 16SrRNA-sequencing analysis results showed that the structure of the ileal flora in the model group was significantly separated from those in the blank group and sham-operated group. The abundance of Lachnospiraceae NK4A136 group was significantly increased （P<0.01）， while that of Escherichia-Shigella was reduced （P<0.05， P<0.01）. Qishengwan at each dose significantly changed the ileal flora structure and regulated the relative abundance of Lachnospiraceae NK4A136 group， Escherichia-Shigella， and Ruminococcaceae. ConclusionQishengwan has a positive therapeutic effect on AD. It can significantly enhance the memory and cognitive abilities in AD rats， which may be related to its regulation of the structure of rat ileal flora and the relative abundance of Lachnospiraceae NK4A136 group， Escherichia-Shigella， and Ruminococcaceae， the attenuation of the central neuroinflammatory response， and the reduction of central Aβ1-42 deposition.
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ObjectiveTo observe the effect of Linggui Zhugantang （LG） on the blood-brain barrier （BBB） model of Alzheimer's disease （AD） in vitro and to explore the mechanism of LG in repairing the BBB injury in AD. MethodA total of 50 male SPF rats were randomized into five groups： high-dose （4.8 g·kg-1）， medium-dose （2.4 g·kg-1）， and low-dose （1.2 g·kg-1） LG groups， western medicine （0.5 g·kg-1 donepezil hydrochloride） group， and normal group （normal saline of equivalent volume）. They received （ig） corresponding drugs twice a day for 7 d. Drug-containing serum was respectively collected from the abdominal aorta 1 h after the last administration. The BBB injury of AD in vitro was induced with the cell co-culture method， and 6 groups were designed： normal group， model group， high-， medium-， and low-dose LG groups， and western medicine group. The model group was added with 100 μL amyloid β1-42 （Aβ1-42， final concentration： 5 μmol·L-1）， and high-dose， medium-dose， and low-dose LG groups and the western medicine group were added with corresponding 10% drug-containing serum in addition to the 100 μL Aβ1-42 （final concentration： 5 μmol·L-1）. Cell survival rate was detected by methyl thiazolyl tetrazolium （MTT） assay， expression of BBB-related skeleton proteins （claudin-5， ZO-1， occludin）， matrix metalloproteinase-2 （MMP-2）， and matrix metalloproteinase-9 （MMP-9） by Western blot， and content of inflammatory factors interleukin-1β （IL-1β）， interleukin-6 （IL-6）， and tumor necrosis factor-α （TNF-α） by enzyme-linked immunosorbent assay （ELISA）. BBB Aβ transporter low-density lipoprotein receptor-related protein 1 （LRP-1） and advanced glycation end product receptor （RAGE） at different time points in high-dose， medium-dose， and low-dose LG groups were determined by Real-time PCR and Western blot. ResultCell survival rate of the model group was lower than that of the normal group （P<0.05） and the survival rates of the western medicine group and high-dose LG group was higher than that in the model group （P<0.05）. The skeleton proteins were down-regulated and MMP-2 and MMP-9 were up-regulated in the model group compared with those in the normal group （P<0.05）. The expression of skeleton proteins was higher （P<0.05） and that of MMP-2 and MMP-9 was lower （P<0.05） in the western medicine group and high-dose LG group than in the model group. Compared with the model group， only the medium-dose LG group showed the up-regulation （P<0.05） of claudin-5 （P<0.05） and the decrease （P<0.05） of MMP-2. IL-1β， IL-6， and TNF-α in the model group were up-regulated （P<0.05） compared with those in the normal group， and those inflammatory factors in the western medicine group and high-dose and medium-dose LG groups were lower （P<0.05） than those in the model group. LRP-1 expression was up-regulated and RAGE expression was down-regulated at 3 h compared with those at 0 h （P<0.05）， while the expression of the two became stable at 6， 12， 24， 36 h. At 3 h， LRP-1 expression was down-regulated and RAGE expression was up-regulated in model group compared with those in the normal group at 3 h （P<0.05）. Moreover， the LRP-1 content was higher and RAGE content was lower in the western medicine group and high-dose LG group than in the model group. ConclusionLG can repair the BBB injury in vitro by inhibiting the expression of inflammatory factors and MMP-2， MMP-9， promoting the expression of skeletal proteins， and regulating the balance of transporters.
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Deficits in the clearance of amyloid β protein (Aβ) by the peripheral system play a critical role in the pathogenesis of sporadic Alzheimer's disease (AD). Impaired uptake of Aβ by dysfunctional monocytes is deemed to be one of the major mechanisms underlying deficient peripheral Aβ clearance in AD. In the current study, flow cytometry and biochemical and behavioral techniques were applied to investigate the effects of polysaccharide krestin (PSK) on AD-related pathology in vitro and in vivo. We found that PSK, widely used in therapy for various cancers, has the potential to enhance Aβ uptake and intracellular processing by human monocytes in vitro. After administration of PSK by intraperitoneal injection, APP/PS1 mice performed better in behavioral tests, along with reduced Aβ deposition, neuroinflammation, neuronal loss, and tau hyperphosphorylation. These results suggest that PSK holds promise as a preventive agent for AD by strengthening the Aβ clearance by blood monocytes and alleviating AD-like pathology.
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Animals , Mice , Alzheimer Disease/pathology , Amyloid beta-Peptides/metabolism , Amyloid beta-Protein Precursor/metabolism , Cognition , Disease Models, Animal , Mice, Transgenic , Monocytes/pathology , Polysaccharides/therapeutic use , ProteoglycansABSTRACT
【Objective】 To investigate the effect of intravenous immunoglobulin(IVIG) with different Aβ antibody content on the cognitive function of Alzheimer′s disease model mice. 【Methods】 IVIG from 8 domestic blood products companies were selected. Enzyme-linked immunosorbent assay(ELISA) was used to detect the content of Aβ40/42 antibody. Three kinds of IVIG with high, middle and low Aβ42/40 antibody levels were selected to treat 3xTg-AD mice. Forty 3-month-old 3xTg-AD mice were randomly divided into 4 groups with 10 mice in each group(half male and half female). Three treat groups were intraperitoneally injected with three kinds of IVIG with 1g·kg-1 for 12 weeks(twice a week). The controls were injected with the same volume of saline. Behavioral tests were performed immediately by using the mouse behavior analysis system after a total of 24 injections. 【Results】 The concentrations of antibodies(μg/mL) against Aβ40 monomer in IVIG ranged 0.7±0.05 to 3.1±0.05, concentrations of antibodies against Aβ40 oligomer ranged 11.7±0.7 to 32.0±2.2, concentrations of antibodies against Aβ42 monomer ranged 1.8±0.1 to 27.9±0.3, and concentrations of antibodies against Aβ42 oligomeric ranged 2.3±0.1 to 49.4±2. High(IVIG-1), medium(IVIG-8) and low(IVIG-6) IVIG were selected for mice study. In the open field test, the time of four groups of mice entering the central area(s) was 0.5±0.9, 23.4±6.1(P<0.0001), 4.6±2.8 and 2.6±2.3, respectively; the number of feces(grains) was 1.6±0.7(P<0.0001), 1.2±0.4(P<0.0001), 2.4±0.5(P<0.001) and 3.8±0.8, respectively. In the novel object recognition test, the scores of exploring new objects were 71.3±29.5(P<0.05), 71.8±20.5(P<0.05), 75.9±26.9(P<0.01) and 25.6±23.7, respectively. In the Barnes maze test, the time of exploring the target hole in the IVIG-8 group was significantly longer than that in the control on the 6th day(50.3±19.3 vs 21±14.6, P<0.05) and the 13th day(58.2±20.9 vs 19.2±15.9, P<0.005), but there was no significant difference between the IVIG-1, 6 groups and the control. 【Conclusion】 There is a significant difference in the level of Aβ40/42 antibody among 8 kinds of domestic IVIG. Domestic IVIG could improve the cognitive function of 3-month-old 3xTg-AD mice after continuous intervention for 3 months. The improvement effect, however, was related to the Aβ antibody in IVIG, but not to the antibody concentration.
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Alzheimer's disease (AD), the most common neurodegenerative disorder, is characterized by memory loss and cognitive dysfunction. The accumulation of misfolded protein aggregates including amyloid beta (Aβ) peptides and microtubule associated protein tau (MAPT/tau) in neuronal cells are hallmarks of AD. So far, the exact underlying mechanisms for the aetiologies of AD have not been fully understood and the effective treatment for AD is limited. Autophagy is an evolutionarily conserved cellular catabolic process by which damaged cellular organelles and protein aggregates are degraded via lysosomes. Recently, there is accumulating evidence linking the impairment of the autophagy-lysosomal pathway with AD pathogenesis. Interestingly, the enhancement of autophagy to remove protein aggregates has been proposed as a promising therapeutic strategy for AD. Here, we first summarize the recent genetic, pathological and experimental studies regarding the impairment of the autophagy-lysosomal pathway in AD. We then describe the interplay between the autophagy-lysosomal pathway and two pathological proteins, Aβ and MAPT/tau, in AD. Finally, we discuss potential therapeutic strategies and small molecules that target the autophagy-lysosomal pathway for AD treatment both in animal models and in clinical trials. Overall, this article highlights the pivotal functions of the autophagy-lysosomal pathway in AD pathogenesis and potential druggable targets in the autophagy-lysosomal pathway for AD treatment.
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Aging is by far the most prominent risk factor for Alzheimer's disease (AD), and both aging and AD are associated with apparent metabolic alterations. As developing effective therapeutic interventions to treat AD is clearly in urgent need, the impact of modulating whole-body and intracellular metabolism in preclinical models and in human patients, on disease pathogenesis, have been explored. There is also an increasing awareness of differential risk and potential targeting strategies related to biological sex, microbiome, and circadian regulation. As a major part of intracellular metabolism, mitochondrial bioenergetics, mitochondrial quality-control mechanisms, and mitochondria-linked inflammatory responses have been considered for AD therapeutic interventions. This review summarizes and highlights these efforts.
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Blood-brain barrier (BBB) strictly controls matter exchange between blood and brain, and severely limits brain penetration of systemically administered drugs, resulting in ineffective drug therapy of brain diseases. However, during the onset and progression of brain diseases, BBB alterations evolve inevitably. In this review, we focus on nanoscale brain-targeting drug delivery strategies designed based on BBB evolutions and related applications in various brain diseases including Alzheimer's disease, Parkinson's disease, epilepsy, stroke, traumatic brain injury and brain tumor. The advances on optimization of small molecules for BBB crossing and non-systemic administration routes (
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Biotransformation of α-asarone by Alternaria longipes CGMCC 3.2875 yielded two pairs of new neolignans, (+) (7S, 8S, 7'S, 8'R) iso-magnosalicin (1a)/(-) (7R, 8R, 7'R, 8'S) iso-magnosalicin (1b) and (+) (7R, 8R, 7'S, 8'R) magnosalicin (2a)/(-) (7S, 8S, 7'R, 8'S) magnosalicin (2b), and four known metabolites, (±) acoraminol A (3), (±) acoraminol B (4), asaraldehyde (5), and 2, 4, 5-trimethoxybenzoic acid (6). Their structures, including absolute configurations, were determined by extensive analysis of NMR spectra, X-ray crystallography, and quantum chemical ECD calculations. The cytotoxic activity and Aβ
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Insurmountable blood‒brain barrier (BBB) and complex pathological features are the key factors affecting the treatment of Alzheimer's disease (AD). Poor accumulation of drugs in lesion sites and undesired effectiveness of simply reducing A
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OBJECTIVE@#To compare the clinical efficacy of abdominal acupoint thread embedding therapy based on "brain-intestinal connection" combined with donepezil hydrochloride tablets and oral donepezil hydrochloride tablets alone for mild-to-moderate Alzheimer's disease (AD) and observe its effects on amyloid precursor protein (APP) and β-amyloid protein@*METHODS@#Sixty patients with AD were randomly divided into an observation group (30 cases, 3 cases dropped off) and a control group (30 cases, 3 cases dropped off). The patients in the control group were treated with donepezil hydrochloride tablets (5 mg per day); based on the treatment in the control group, the patients in the observation group were treated with abdominal acupoint thread embedding therapy at Zhongwan (CV 12), Xiawan (CV 10), Huaroumen (ST 24), Wailing (ST 26), Daheng (SP 15), etc., once every 10 days. Both groups were treated for 2 months. The mini-mental state examination (MMSE), Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog), activity of daily living scale (ADL), neuropsychiatric inventory questionnaire (NPI) as well as the serum levels of APP and Aβ@*RESULTS@#After treatment, the MMSE scores in the two groups were higher than those before treatment (@*CONCLUSION@#The abdominal acupoint thread embedding therapy based on the theory of "brain-intestinal connection" combined with donepezil hydrochloride tablets can improve cognitive function, self-care ability of daily life and mental behavior, and reduce the serum levels of APP and Aβ
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Humans , Acupuncture Points , Alzheimer Disease/drug therapy , Amyloid beta-Peptides , Amyloid beta-Protein Precursor , Brain , Donepezil , Peptide FragmentsABSTRACT
Objective:To investigate the neuroprotective effect of Danggui Shaoyaosan （DSS） in a rat model of amyloid-<italic>β</italic>-peptide<sub>1-42</sub> （A<italic>β</italic><sub>1-42</sub>）-induced Alzheimer's disease （AD） as well as its regulatory effect on NOD-like receptor protein 3 （NLRP3）/cysteinyl aspartate-specific protease-1 （Caspase-1） signaling pathway. Method:The AD animal model was established via intracerebral injection of A<italic>β</italic><sub>1-42</sub> and treated with different concentrations of DSS after the division of rats into the sham operation group， model group， as well as the high-， medium-， and low-dose DSS groups. Morris water maze test was conducted to determine the learning and memory abilities of rats. The morphology and function of neurons were detected by hematoxylin-eosin （HE） staining and Golgi staining， followed by immunofluorescence co-localization of NLRP3 inflammasome activation. The mRNA expression levels of interleukin （IL）-1<italic>β</italic> and IL-18 were measured by Real-time polymerase chain reaction （Real-time PCR）， and the protein expression levels of NLRP3， Caspase-1， and IL-1<italic>β </italic>were assayed by Western blot. Result:Compared with the sham operation group， the model group exhibited significantly decreased learning and memory abilities （<italic>P</italic><0.01）， impaired neuronal morphology and function， up-regulated IL-1<italic>β</italic> and IL-18 mRNA expression， enhanced NLRP3 inflammasome activation， and elevated NLRP3， Caspase-1， and IL-1<italic>β</italic> protein expression （<italic>P</italic><0.01）. Compared with the model group， DSS at both medium and high doses remarkably improved the learning and memory abilities of AD rats （<italic>P</italic><0.05， <italic>P</italic><0.01）， restored neuronal morphology and function， down-regulated the mRNA expression levels of inflammatory factors IL-1<italic>β</italic> and IL-18， reduced the activation of NLRP3 inflammasomes， and lowered the protein expression levels of NLRP3， Caspase-1， and IL-1<italic>β</italic> （<italic>P</italic><0.01）. Conclusion:DSS inhibits inflammasome activation and neuroinflammatory response possibly by regulating the NLRP3/Caspase-1 signaling pathway， thus exerting the neuroprotective effect.
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Objective To explore the effects of Humulus lupulus L. extract (HLE) and its mechanism on improving bone formation of Aβ-injured osteoblasts. Methods Osteoblasts isolated from 24 h-old Wistar rats were injured by Aβ1-42 oligomer and intervened with HLE. The proliferation, differentiation and bone mineralization of osteoblasts were determined by MTT assay, alkaline phosphatase (ALP) activity assay and alizarin red staining, respectively. The apoptosis of osteoblasts was detected by flow cytometer. The expression levels of bone formation related proteins, and proteins of Nrf2 and FoxO1 pathways were measured by Western blotting analysis. The intranuclear expression of FoxO1 protein was detected by immunofluorescence. Results HLE significantly improved the cell proliferation, ALP activity and bone mineralization, and inhibited the apoptosis of Aβ-injured osteoblasts. HLE also significantly promoted the expressions of collagen type Ι (COL-I) and osteopontin (OPN) in Aβ-injured osteoblasts. HLE notably activated the Nrf2 and FoxO1 signaling pathways in Aβ-injured osteoblasts by promoting the expressions of related proteins and maintained bone metabolism through relieving oxidative stress. Conclusion This study confirms that HLE can alleviate Aβ-injury to osteoblasts, and preliminarily clarifies the mechanism being related to antioxidation, which provides a new reference for the mechanism research and drugs development for anti-osteoporosis.
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Background The interaction of the receptor for advanced glycation end product (RAGE) on blood-brain-barrier(BBB) with amyloid β (Aβ) plays an important role in the occurrence and development of AD. RP1 is a RAGEspecific binding peptide, which was discovered in our previous experiments, and it has been proved to beeffective on AD cell model, however, its effects on BBB tight junctions (TJs) and on Aβ transport into the brain isunclear.Methods Immunofluorescence experiment was used to identify whether RP1 bound with RAGE specifically.BEnd3-immortalized mouse brain microvascular endothelial cells were used to construct a BBB model. TEER andFD40 tests were used to confirm the stability of the BBB model, and the colocalization of the RP1 and RAGE onthe surface bEnd3 cells was observed with confocal microscopy.Results We confirmed that RP1 can bind to RAGE specifically in vitro. Functional analyses indicated that RP1 caneffectively alleviate the destroy of TJs of BBB and the decrease of permeability of BBB caused by Aβ. Furthermore,RP1 can competitively inhibit the interaction of Aβ with the RAGE in vitro, and effectively inhibit Aβ transport intothe brain.Conclusion RP1 can inhibit BBB damage induced by Aβ and block RAGE-Aβ interaction effectively, and RP1 canbe a candidate of RAGE inhibitors contributing to AD treatment
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OBJECTIVE@#To investigate the effects of stachydrine (STA) on apoptosis of Aβ-induced PC12 cells mimicking Alzheimer's disease and explore the mechanisms.@*METHODS@#The differential genes of STA were analyzed based on GSE85871 data, and the target genes of STA were identified using STITCH database. PC12 cells were treated with Aβ to establish a cell model of Alzheimer's disease, and the changes in cell viability and cell cycle in response to STA treatment were assessed using MTT assay and flow cytometry, respectively. RT-PCR and Western blotting were used to detect the relevant gene or protein expressions in the treated cells.@*RESULTS@#GSE85871 data showed 37 up-regulated genes and 48 down-regulated genes in cells following treatment with STA. Analysis of the data from the STITCH database indicated that RPS8 and EED were the target genes of STA. Treatment of PC12 cells with Aβ significantly lowered the cell viability ( < 0.05) and the expressions of RPS8 and EED at both the mRNA and protein levels ( < 0.05), and obviously inhibited the expression of apoptosis-related proteins Bcl-2 and p53 ( < 0.05). STA treatment of the cells significantly reversed the effect of Aβ and induced cell cycle arrest in G2/M phase, causing also significantly increases in the expression levels of RPS8, EED, Bcl-2 and p53 ( < 0.05).@*CONCLUSIONS@#STA plays an important role in inhibiting the apoptosis of PC12 cells induced by Aβ possibly by regulating RPS8 and EED expression to promote the expressions of Bcl-2 and p53.
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Animals , Rats , Alzheimer Disease , Amyloid beta-Peptides , Apoptosis , Cell Survival , PC12 Cells , Peptide FragmentsABSTRACT
Objective To explore the effect and potential mechanism of tenuigenin (TEN) treatment on ameliorating cognitive impairment of Alzheimer's disease (AD) model mice. Methods 6-month-old APP/PS1 transgenic mice (n=18) were randomly divided into the saline group and TEN group (9 each), 9 wild-type mice of the same age were selected as control group. Mice in TEN group were intraperitoneally injected with TEN at a dose of 8 mg/(kg.d) for 8 weeks, those in both saline group and control group were intraperitoneally injected with same dose of saline for 8 weeks. The Morris water maze test was carried out with all the mice of the three groups to assess the spatial memory level, and immunohistochemistry was performed to detect the distribution and expression of postsynaptic density protein 95 (PSD-95) in hippocampal area of brain, and thioflavin staining was performed to check the senile plaque in hippocampus. ELISA was used to assess the Aβ42 level. Western blotting was used to detect the levels of PSD-95 and p-tau protein (Ser231, Ser214, Ser396) in brain. Results In the Morris water maze test, mice in saline group exhibited greater escape latency compared with that of mice in control group after the second day, the difference was statistically significant (P0.05); mice in TEN group exhibited longer escape latency compared with that of control group at the 5th day. Space search trial found that mice in saline group spent obviously longer time to find the original position of the platforms than those in control group [(40.428±3.408) s vs. (14.142±7.289) s, P0.05). It was found that mice in saline group exhibited fewer times of crossing platform than those in control group (0.428±0.035 vs. 2.285±1.380, P0.05). The relative amount of PSD-95 was lower in mice of saline group than that in control group (0.570±0.700 vs. 0.740±0.054), the difference was statistically significant (P0.05). The number of plaques and Aβ42 level in hippocampus decreased significantly in TEN group than those in saline group [(8.889±1.692 vs. 18.000±2.000) and (2.859±0.864) ng/mg vs. (5.154±0.735) ng/mg, P<0.05]. As to the expression level of protein p-tau Ser231, Ser214 and Ser396 in mice hippocampus, they were higher significantly in saline group than those in control group (0.947±0.131 vs. 0.540±0.076, 0.832±0.161 vs. 0.305±0.088 and 0.819±0.053 vs. 0.338±0.052, P<0.05), while they were obviously lower in TEN group than in saline group (0.568±0.051 vs. 0.947±0.131, 0.472±0.094 vs. 0.832±0.161 and 0.452±0.071 vs. 0.819±0.053, P<0.05). The expression levels of protein p-tau Se214 and Ser396 in mice hippocampus of TEN group were higher than those in control group with statistical significance (0.472±0.094 vs. 0.305±0.088 and 0.452±0.071 vs. 0.338±0.052, P<0.05), but the expression level of p-tau Ser231 showed no significant difference between TEN group and control group (0.568±0.051 vs. 0.540±0.076). Conclusion Tenuigenin may attenuate cognitive deficits by up-regulating the PSD-95 level in APP/PS1 mice, decrease Aβ deposition and excessive phosphorylation of protein p-tau, and might be a potential therapeutic agent for Alzheimer's disease.
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BACKGROUND: Deposition of neurofibrillary tangles is closely related to cognitive decline in Alzheimer’s disease, and tau protein is an important component. OBJECTIVE: To investigate the possible pathogenesis of Alzheimer’s disease and the role of tau protein hyperphosphorylation in the progression of Alzheimer’s disease. METHODS: The first author searched for relevant articles published from January 2001 to January 2019 in WanFang, CNKI, Vip, PubMed, and Embase with the key words of “Alzheimer’s disease; tau protein; β-amyloid cascade.” RESULTS AND CONCLUSION: Hyperphosphorylation of tau protein and formation of paired helix filaments are considered to be the basis of neuronal degradation in Alzheimer’s disease. tau protein may not depend on the cascade response triggered by β-amyloid deposition in the pathogenesis of Alzheimer’s disease, and tau protein-associated vaccine immunity has been verified to produce a curative effect in clinical trials. Further exploration on the relationship between tau protein, β-amyloid protein and Alzheimer’s disease is necessary to better understand the pathogenesis of Alzheimer’s disease, and provide a theoretical basis for the development of therapeutic drugs for Alzheimer’s disease.
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Objective::To observe the effect of Huangjingwan (HW) on antioxidant functions and β-amyloid 1-42 (Aβ1-42) and amyloid precursor protein (APP) expressions in the brain of Alzheimer' s disease (AD) rats. Method::SD rats were randomly divided into normal control group, sham model control group, AD model group, and low, medium, high-dose (equivalent raw drug dose 1, 3, 9 g·kg-1·d-1) HW groups.The AD models were established through intraperitoneal injection with 1.25% D-galactose (120 mg·kg-1·d-1, 6 consecutive weeks) and then one-time right ventricular injection with Aβ1-42 (10 μg). Two weeks after modeling, the rats in each HW group received corresponding drugs through intragastric administration, once a day, while the rats in sham model control group, AD model group were given normal saline 1 mL through intragastric administration, once a day.Gastric perfusion lasted for 8 weeks.At the end of the experiment, learning and memory abilities of the rats were assessed by Platform Jumping Test.The changes of physical endurance in rats were tested by 10% weight swimming under load.The activities of superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GSH-Px) antioxidant enzymes and the contents of glutathione (GSH) and malondialdehyde (MDA) in rat brain tissue were detected by colorimetry.The changes of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), Aβ1-42 and APP protein in rat brain tissues were determined by enzyme linked immunosorbent assay (ELISA). Western blot analysis was used to measure the expression of APP protein in rat brain. Result::Compared with the normal control group, rats in AD model group showed an obvious dementia state, that is more lying and less movement, longer learning response time, significant increase in the number of learning and memory errors, significant attenuation in physical fitness, significant decrease in the activities of antioxidant enzymes (SOD, GR, GSH-Px) and anti-inflammatory factors GSH in brain, significant rise in the levels of inflammatory factors MDA, IL-1β and TNF-α and the content of Aβ1-42 protein, and significant reduction in the content of APP protein in brain (P<0.01). Low, medium and high-dose HW could ameliorate dementia symptoms in AD rats, improve the achievement of learning and memory, antagonize body weakness and increase physical fitness, promote SOD, GR, GSH-Px activities and anti-inflammatory factor GSH level in the brain, reduce the levels of MDA, IL-1β and TNF-α in the brain, decrease the level of Aβ1-42 and increase the level of APP protein in the brains of AD rats compared with the AD model group (P<0.05, P<0.01), besides, within the dose range of 1-9 g·kg-1·d-1, HW has a more obvious effect with the increase of dose. Conclusion::HW has the effects in preventing and treating AD, which is related to the HW' s mechanisms in enhancing the function of antioxidant system in brain, reducing neuroinflammatory reaction and deposition of Aβ1-42 induced by oxidative stress, and maintaining the expression level of APP protein.
ABSTRACT
Objective:To investigate the effects of naringenin on oxidative stress and Tau protein phosphorylation of adrenal pheochromocytoma（PC12） cells injured by β-amyloid（Aβ）25-35 and its relationship with estrogen receptor（ER） and phosphatidylinositol -3 kinase/protein kinase B（PI3K/Akt） signaling pathway. Method:The PC12 cells were intervened with Aβ25-35 to prepare the injury model. The experiment was divided into blank group， model group， naringenin（400，40，4，0.4，0.04，4×10-3，4×10-4，4×10-5 μmol·L-1）group， positive drugs estradiol（E2）（1 nmol·L-1）+Aβ25-35 group， naringenin（0.4，0.04，4×10-3，4×10-4，4×10-5 μmol·L-1）+Aβ25-35 group， E2+Aβ25-35+ER antagonist（ICI182780）（1 μmol·L-1） group， naringenin+Aβ25-35+ICI182780 group， E2+Aβ25-35+PI3K blocker（LY294002）（50 μmol·L-1） group， naringenin+Aβ25-35+LY294002 group. Methye thiazolye telrazlium（MTT）method was used to detect the cell proliferation index， 2'，7'-Dichlorodi -hydrofluorescein diacetate（DCFH-DA） was used as a fluorescent probe to detect the content of reactive osygen species（ROS）， the content of malondialdehyde（MDA） and the activity of superoxide dismutase（SOD） were measured by thiobarbituric acid（TBA） and oxidase methods， Western blot was used to detect the expression of phosphorylated Tau protein/total Tau protein（p-Tau/t-Tau）. Result:According to the results of MTT experiment， 0.4 μmol·L-1 was selected as the best effective concentration of naringenin， compared with the blank group， the cell proliferation index of model group decreased significantly （P<0.01）， compared with model group， the cell proliferation index of naringenin+Aβ25-35 group increased significantly （P<0.01）. In addition， compared with blank group， the content of ROS， MDA and the expression of p-Tau/t-Tau in the model group increased significantly （P<0.01）， and the activity of SOD decreased significantly （P<0.01）， compared with model group， the content of ROS， MDA and the expression of p-Tau/t-Tau in naringenin+Aβ25-35 group decreased significantly （P<0.01）， and the activity of SOD increased significantly （P<0.01）， compared with naringenin+Aβ25-35 group， the addition of ICI182780 and LY294002 significantly reversed the role of naringenin in the above indicators （P<0.01）. The effect of naringenin was similar to that of E2. Conclusion:Naringenin can improve the cell proliferation index and protect PC12 cells from Aβ25-35 injury， which may be achieved by activating ER and PI3K/Akt signaling pathway to reduce ROS， MDA content， p-Tau/t-Tau expression and promote SOD activity.