Alzheimer's disease (AD) is a highly age-related cognitive decline frequently attacking the elderly. Senescence-accelerated mouse-prone 8 (SAMP8) is an ideal model to study AD, displaying age-related ...learning and memory disorders. SAMP8 mice exhibit most features of pathogenesis of AD, including an abnormal expression of anti-aging factors, oxidative stress, inflammation, amyloid-β (Aβ) deposits, tau hyperphosphorylation, endoplasmic reticulum stress, abnormal autophagy activity, and disruption of intestinal flora. SAMP8 mice, therefore, have visualized the understanding of AD, and also provided effective ways to find new therapeutic targets. This review focused on the age-related pathogenesis in SAMP8 mice, to advance the understanding of age-related learning and memory decline and clarify the mechanisms. Furthermore, this review will provide extensive foundations for SAMP8 mice used in therapeutics for AD.
Overexpression of P2X7R has been observed in several tumours and is related to cancer advancement and metastasis. However, the role of P2X7R in colorectal cancer (CRC) patients is not well ...understood. In the current study, overexpression of P2X7R and the effects at the molecular and functional levels in CRC were assessed in a mouse orthotopic model. Functional assays, such as the CCK‐8 assay, wound healing and transwell assay, were used to determine the biological role of P2X7R in CRC cells. CSC‐related genes and properties were detected via sphere formation and real‐time PCR assays. The underlying mechanisms were explored by Western blotting, real‐time PCR and Flow cytometry. In this study, we found that overexpression of P2X7R increases in the in vivo growth of tumours. P2X7R overexpression also increased CD31, VEGF and concurrent angiogenesis. P2X7R up‐regulates aldehyde dehydrogenase‐1 (ALDH1) and CSC characteristics. Transplanted tumour cells with P2X7R overexpression stimulated cytokines to recruit tumour‐associated macrophage (TAMs) to increase the growth of tumours. We also found that the NF‐κB signalling pathway is involved in P2X7R‐induced cytokine up‐regulation. P2X7R promotes NF‐κB–dependent cytokine induction, which leads to TAM recruitment to control tumour growth and advancement and remodelling of the stroma. Our findings demonstrate that P2X7R plays a key role in TAM recruitment, which may be a therapeutic target for CRC patients.
Neuroinflammation is an important contributor to pathogenesis of neurological disorders, with microglial activation as a hallmark of neuroinflammation. Microglia serve the role of immune surveillance ...under normal conditions, but after brain damage or exposure to inflammation, microglia are activated and secrete pro-inflammatory and neurotoxic mediators. Sustained production of these factors contributes to neuronal damage. Therefore, inhibition of microglia-mediated neuroinflammation may become a promising therapeutic target for neurological disorders. Resveratrol, a non-flavonoid polyphenol rich in red wine and grapes, has beneficial health effects from its antioxidant, anticancer and anti-inflammatory properties. Recently, resveratrol has been shown to protect against various neurological disorders in experimental models, including brain ischemia, seizures, and neurodegenerative disease models. This minireview summarized the anti-inflammatory activities of resveratrol in the brain from both
in vivo and
in vitro studies, and highlighted the inhibition of activated microglia as a potential mechanism of neuroprotection. The release of various pro-inflammatory factors, the production of reactive oxygen species, and the activation of signal pathways leading to neuroinflammation were discussed in relation to microglial activation. Taken together, microglia are an important target for anti-inflammatory activities of resveratrol in the brain.
Neuroinflammation is considered to be an important and inevitable pathological process associated with all types of damages to, and disorders of, the central nervous system. The hallmark of ...neuroinflammation is the microglia activation. In response to different micro-environmental disturbances, microglia could polarize into either an M1 pro-inflammatory phenotype, exacerbating neurotoxicity, or an M2 anti-inflammatory phenotype, exerting neuroprotection. Therefore, shifting the polarization of microglia toward the M2 phenotype could possess a more viable strategy for the neuroinflammatory disorders treatment. Naringenin (NAR) is naturally a grapefruit flavonoid and possesses various kinds of pharmacological activities, such as anti-inflammatory and neuroprotective activities. In the present study, we aimed to investigate the potential effects of NAR on microglial M1/M2 polarization and further reveal the underlying mechanisms of actions. First, NAR inhibited lipopolysaccharide (LPS)-induced microglial activation. Then, NAR shifted the M1 pro-inflammatory microglia phenotype to the M2 anti-inflammatory M2 microglia state as demonstrated by the decreased expression of M1 markers (i.e., inducible TNF-α and IL-1β) and the elevated expression of M2 markers (i.e., arginase 1, IL-4, and IL-10). In addition, the effects of NAR on microglial polarization were dependent on MAPK signaling, particularly JNK inactivation, as evidenced by the fact that the selective activator of JNK abolished NAR-promoted M2 polarization and further NAR-inhibited microglial activation. Together, this study demonstrated that NAR promoted microglia M1/M2 polarization, thus conferring anti-neuroinflammatory effects via the inhibition of MAPK signaling activation. These findings might provide new alternative avenues for neuroinflammation-related disorders treatment.
•GSK-3β is involved in the physiological and pathological progress of DM and AD respectively.•In DM, GSK-3β is one of the key factors leading to insulin deficiency and insulin resistance.•In AD, ...GSK-3β plays an important role in hyperphosphorylation of microtubule-associated protein tau.•GSK-3β as a potential link between DM and AD is reviewed.•GSK-3β as a link between DM and AD further supports that AD is regarded as Type 3 diabetes.
It is well known that Alzheimer’s disease (AD) is closely related to diabetes mellitus (DM), and AD is also regarded as Type 3 diabetes (T3D). However, the exact link between AD and DM is still unclear. Recently, more and more evidence has shown that glycogen synthase kinase-3β (GSK-3β) may be the potential link between DM and AD. In DM, GSK-3β is the crucial enzyme of glycogen synthesis, which plays a key role in regulating blood glucose. More importantly, GSK-3β is one of the key factors leading to insulin deficiency and insulin resistance, and insulin resistance is an important hallmark of the occurrence and development of DM. In AD, GSK-3β plays an important role in hyperphosphorylation of microtubule-associated protein tau (tau), which is one of the pathological features in AD. GSK-3β is one of the important kinases of tau phosphorylation and is involved in the insulin/phosphoinositide 3-kinase/protein kinase B (insulin/PI3K/Akt) signaling pathway. Dysfunction of the insulin/PI3K/Akt signaling pathway, which regulates glucose metabolism in the brain, can lead to tau hyperphosphorylation in the brain of AD patents. Additionally, insulin resistance in DM may cause β-amyloid (Aβ) deposition, which will be cleared by tau, but excessive phosphorylation of tau will further aggravate the neurotoxicity; then damage the brain and affect the cognitive function. GSK-3β is considered as a common kinase in insulin signaling transduction and tau protein phosphorylation, so we have reasons to believe that GSK-3β is a potential link between DM and AD.
Neurodegenerative diseases are a heterogeneous group of disorders characterized by the progressive degeneration of the structure and function of the central nervous system or peripheral nervous ...system. Alzheimer's Disease (AD), Parkinson's Disease (PD) and Spinal Cord Injury (SCI) are the common neurodegenerative diseases, which typically occur in people over the age of 60. With the rapid development of an aged society, over 60 million people worldwide are suffering from these uncurable diseases. Therefore, the search for new drugs and therapeutic methods has become an increasingly important research topic. Natural products especially those from the Traditional Chinese Medicines (TCMs), are the most important sources of drugs, and have received extensive interest among pharmacist. In this review, in order to facilitate further chemical modification of those useful natural products by pharmacists, we will bring together recent studies in single natural compound from TCMs with neuroprotective effect.
Cerebral ischemia/reperfusion (I/R) results in harmful consequences during ischemic stroke, especially the disruption of the blood-brain barrier (BBB), which leads to severe hemorrhagic ...transformation through aggravation of edema and brain hemorrhage. Our previous study demonstrated that icariside II (ICS II), which is derived from Herba Epimedii, attenuates cerebral I/R injury by inhibiting the GSK-3β-mediated activation of autophagy both in vitro and in vivo. However, the effect of ICS II on the BBB remains unclear. Thus, in this study, we investigated the regulation of BBB integrity by ICS II after cerebral I/R injury and further explored the underlying mechanism in rats. Cerebral I/R injury was induced by middle cerebral artery occlusion (MCAO), and the treatment groups were administered ICS II at a dose of 16 mg/kg by gavage twice a day for 3 days. The results showed that ICS II effectively prevented BBB disruption, as evidenced by Evans Blue staining. Moreover, ICS II not only significantly reduced the expression of MMP2/9 but also increased TIMP1 and tight junction protein (occludin, claudin 5, and ZO 1) expression. Intriguingly, ICS II may directly bind to both MMP2 and MMP9, as evidenced by molecular docking. In addition, ICS II also inhibited cerebral I/R-induced apoptosis and ameliorated the Bax/Bcl-2 ratio and cleaved-caspase 3 level. Collectively, our findings reveal that ICS II significantly ameliorates I/R-induced BBB disruption and neuronal apoptosis in MCAO rats by regulating the MMP9/TIMP1 balance and inhibiting the caspase 3-dependent apoptosis pathway.
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•DNLA and metformin ameliorated cognitive decline in aged SAMP8 mice.•Age-associated neuron loss and ER damage was improved by DNLA and metformin.•DNLA and metformin decreased ER ...stress-related PERK signaling pathway.•DNLA decreased calpain 1, GSK-3β and Cdk5 activities and Tau hyperphosphorylation.•These beneficial effects of DNLA were comparable to metformin.
The senescence-accelerated mouse prone 8 (SAMP8) mice have many pathological features of Alzheimer’s disease (AD) with aging. We previously reported that Dendrobium nobile Lindl alkaloid (DNLA) effectively improved cognitive deficits in multiple Alzheimer’s disease (AD) models. This study further used SAMP8 mice to study the anti-aging effects of DNLA, focusing on endoplasmic reticulum (ER) stress. DNLA and metformin were orally administered to SAMP8 mice starting at 4-month of age for 6 months. Behavioral tests were performed in 10-month-old SAMP8 mice and age-matched SAMR1 control mice. At the end of experiment, neuron damage was evaluated by histology and transmission electron microscopy. ER stress-related proteins were analyzed with Western-blot. DNLA improved learning and memory impairments, reduced the loss of neurons and Nissl bodies in the hippocampus and cortex. DNLA ameliorated ER dilation and swelling in the hippocampal neurons. DNLA down-regulated the protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling pathway, decreased calpain 1, GSK-3β and Cdk5 activities and the Tau hyper-phosphorylation. The effects of DNLA were comparable to metformin. In summary, DNLA was effective in improving cognitive deficits in aged SAMP8 mice, possibly via suppression of ER stress-related PERK signaling pathway, sequential inhibition of calpain 1, GSK-3β and Cdk5 activities, and eventually reducing the hyper-phosphorylation of Tau.
Continuous capture with affinity chromatography is one of the most important units for continuous manufacturing of monoclonal antibody (mAb). Due to the complexity of three‐column periodic ...counter‐current chromatography (3C‐PCC), three approaches (experimental, model‐based, and simplified approaches) were studied for process development and optimization. The effects of residence time for interconnected load (RT
C), breakthrough percentage of the first column for interconnected load (s) and feed protein concentration (c
0) on productivity and capacity utilization were focused. The model‐based approach was found superior to the experimental approach in process optimization and evaluation. Two phases of productivity were observed and the optimal RT
C for the maximum productivity was located at the boundary of the two phases. The comprehensive effects of the operating parameters (RT
C, s, and c
0) were evaluated by the model‐based approach, and the operation space was predicted. The best performance of 34.5 g/L/h productivity and 97.6% capacity utilization were attained for MabSelect SuRe LX resin under 5 g/L concentration at RT
C = 2.8 min and s = 87.5%. Moreover, a simplified approach was suggested to obtain the optimal RT
C for the maximum productivity. The results demonstrated that model‐assisted tools are useful to determine the optimum conditions for 3C‐PCC continuous capture with high productivity and capacity utilization.
Three‐column periodic counter‐current chromatography for continuous affinity capture was investigated and three approaches (experimental, model‐based, and simplified approaches) were compared to characterize the operating parameters for process optimization. Compared with the experimental approach, the model‐based approach was superior for high efficiency and accuracy, which provides a useful tool to evaluate the continuous process in a comprehensive way. A simplified approach was proposed as an alternative for the model‐based approach with less computational requirement and fast evaluation.
Background. Excessive or insufficient intake of methionine (Met) causes neuronal dysfunction, neurodegeneration, cerebrovascular dysfunction, vascular leakage, and short-term memory loss, which ...result in the occurrence of Alzheimer’s disease- (AD-) like symptoms. Objective. To determine the relationship between high methionine diets (HMD) induced AD-like symptoms and 5-methylcytosine (5-mC) level. Methods. C57BL/6J mice were randomly divided into two groups: the control group (Maintain diets) and the model group (2% HMD). Mice were fed with 2% HMD for 9 weeks. Animals were weighed and food intake was recorded weekly. Open field test, nesting ability test, Y maze test, new object recognition test, and Morris water maze test were used to detect the motor, learning, and memory ability. Hematoxylin-eosin (HE) staining was used to observe the damage of cells in hippocampus and cortex. Immunofluorescence (IF) staining was used to detect the expression and distribution of amyloid-β 1-40 (Aβ1-40), amyloid-β 1-42 (Aβ1-42), and 5-methylcytosine (5-mC) in hippocampus and cortex. Western blotting (WB) was used to determine the expression of Aβ and DNA methyltransferases- (DNMTs-) related proteins in the cortex. Enzyme-linked immunosorbent assay (ELISA) was performed to detect homocysteine (Hcy) level (ELISA). Results. Feeding of HMD decreased the body weight and food intake of mice. Behavioral testing revealed that HMD caused learning, memory, and motor ability impairment in the mice. HE staining results showed that HMD feeding caused damage of hippocampal and cortical neurons, along with disordered cell arrangement, and loss of neurons. Furthermore, HMD increased the contents of Aβ1-40, Aβ1-42, and 5-mC in the hippocampus and cortex. WB results showed that HMD increased the expression of Aβ production-related proteins, such as amyloid precursor protein (APP) and beta-secretase 1 (BACE1), and decreased the expression of Aβ metabolism-related protein in the cortex, including insulin-degrading enzyme (IDE) and neprilysin (NEP). Additionally, the decreased expression of DNA methyltransferase1 (DNMT1) was observed in HMD-treated mice, but there was no significant change of DNMT3a level. ELISA results showed that HMD increased the levels of Hcy in serum. Conclusion. Our result suggested that the HMD can cause neurotoxicity, leading to AD-like symptoms in mice, which may be related to 5-mC elevated.
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