LncRNA NEAT1 ameliorate ischemic stroke via promoting Mfn2 expression through binding to Nova and activates Sirt3.

BACKGROUND: Recent studies revealed that long non-coding RNAs (lncRNAs) have significant roles in regulating the pathogenesis of ischemia stroke, and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cell apoptosis. Aberrant expression of NEAT1 was found after the injury of ischemia-reperfusion, but the mechanism was not fully understood. METHODS: The expression of NEAT1 and Mfn2 were detected in BV-2 and N2a cell with or without OGD/R-induced by qRT-PCR. Inflammatory cytokines secretion was detected by enzyme-linked immunosorbent assay (ELISA). The oxidative stress was evaluated by the examination of ROS, MDA and SOD levels. Flow cytometry and apoptosis marker detection by western blot were performed to examined apoptosis. RESULTS: The expression of NEAT1 and Mfn2 were decreased in OGD/R-induced cell model. Overexpression of NEAT1 or Mfn2 reduced oxidative stress and apoptosis by OGD/R-induced in neuronal cells, while knockdown of Sirt3 reversed the protective effect of NEAT1 and Mfn2. NEAT1 stabilized Mfn2 mRNA via recruiting Nova. NEAT1 alleviates the oxidative stress and apoptosis by OGD/R-induced via activating Sirt3. CONCLUSION: LncRNA NEAT1 stabilizes Mfn2 mRNA via recruiting Nova, therefore increase the expression of Mfn2 and alleviates ischemia-reperfusion induced oxidative stress and apoptosis via Mfn2/Sirt3 pathway.

The Association of Blood Urea Nitrogen to Creatinine Ratio and the Prognosis of Critically Ill Patients with Cerebral Infarction: A Cohort Study.

Background: To evaluate the association between blood urea nitrogen (BUN) to creatinine (Cr) (BUN/Cr) ratio and the in-hospital mortality of critically ill patients with cerebral infarction in intensive care unit (ICU). Methods: In this cohort study, the data of 3059 participants with cerebral infarction were collected from the Medical Information Mart for Intensive Care (MIMIC)-III and the MIMIC-IV database. After propensity score matching (PSM) on age and gender, 2085 people were involved in and divided into the alive group (n = 1390) and the dead group (n = 695) based on the results of follow-up. Multivariate logistic analyses were applied to identify the confounders and the association between BUN/Cr and mortality of cerebral infarction. Results: The median follow-up time was 10.5 days. Among 2778 participants, 695 were dead at the end of follow-up. Univariate analysis revealed that BUN/Cr [risk ratio (RR) = 1.01, 95% confidence interval (CI): 1.01-1.02] might be associated with the in-hospital mortality of cerebral infarction patients. After adjusting for respiratory failure, malignant cancer, anticoagulation, liver disease, white blood cell (WBC), red cell distribution width (RDW), glucose, bicarbonate, and temperature, BUN/Cr had week correlation with the increased risk of in-hospital mortality of cerebral infarction patients (RR = 1.01, 95% CI: 1.01-1.02). Conclusion: This study evaluated the association between BUN/Cr and the in-hospital mortality of cerebral infarction patients in ICU and found that BUN/Cr had weak correlation with the increased risk of in-hospital mortality of patients with cerebral infarction in ICU especially in males and those with respiratory failure, malignant cancer, and without liver disease, as well as those receiving anticoagulation.

Evaluation of Injury Degree of Adriamycin-Induced Nephropathy in Rats Based on Serum Metabolomics Combined with Proline Marker.

Nephrotic syndrome (NS) is one of the leading causes of end-stage renal failure. Unfortunately, reliable surrogate markers for early diagnosing and monitoring the entire progression of NS are as yet absent. A method using UPLC-Q exactive HR-MS was established for the serum metabolomic study of adriamycin-induced nephropathy in rats. Two rat nephropathy models induced by adriamycin were adopted to reflect different degrees of renal damage of early and advanced stages. Then two MPC5 cell models were used to verify the role of proline in the progression of kidney injury. The results showed that seven metabolites such as 14S-HDHA, DPA, and DHA were associated with early renal injury, while 12 metabolites such as tryptophan, linoleyl carnitine, and LysoPC (18:3) reflected the advanced renal disease. At the same time, metabolites including LPE (22:6), LysoPC (22:5), and proline that changed during the whole process of NS were defined as progressive markers. Pathway analysis results showed that fatty acid metabolism, glycerophospholipid metabolism, and amino acids metabolism participated in the occurrence and development of NS. In addition, the change trend of intracellular proline content was consistent with that in serum, and the results were further supported by the detection of the crucial gene PYCRL. This study provides an important basis for searching for diagnostic markers of NS and also provides a methodological reference for early diagnosing and monitoring the pathogenesis of other progressive diseases.

[Research progress on identification of pharmacodynamic substance basis of traditional Chinese medicine based on target constituent knock-out/knock-in technology].

The effective material basis of traditional Chinese medicine(TCM) is an indispensable part of studies on TCM, and each technology has its advantages and disadvantages. The target constituent knock-out/knock-in technology has attracted much attention since it was proposed because of its unique advantages of regarding the extract of the formula as a whole, which can better reflect the characteristics of multi-component and multi-target integration and regulation of TCM. This method investigated the contribution of target constituent to the overall efficacy of a TCM by analyzing the changes in efficacy of the remaining formula before and after knock-out/knock-in of the target constitution. The application of this model not only facilitates studies of the effective constituents of TCM, but also help to develop the quality control standard of TCM. However, the application of this model is restricted due to the limitation of target constituent separation technology. By reviewing the literatures in recent years, this study summarized the research process and application of this method for a reference.

[Optimization of determination methods of astragaloside â £ and analysis of contents of astragaloside â £ in different origin and grade].

A rapid and accurate method for determination of astragaloside Ⅳ was established,which was further applied to determine the contents of astragaloside Ⅳ in 87 batches of different origin and different grade of Astragali Radix. The ROC curve was used to analyze the contents of astragaloside Ⅳ in different origin. Simultaneous contents of astragaloside Ⅳ in different grade were compared with chemometrics. HPLC-ELSD method was used to determine the contents of astragaloside Ⅳ. A Vensil MP C18 column( 4. 6 mm×250 mm,5 µm) was used with acetonitrile-water( 32 ∶68) as the mobile phase at a flow rateof 1 m L·min-1. The column temperature was 25 ℃ with ELSD parameters as follows: gas flow rate was 2. 5 L·min-1,the drift tube heating temperature was set to 105 ℃,and the gain value was 4. 0. The optimized method avoided the problem that the consumable quality unstable and the recovery rate was not high. The contents determined by the optimized method were higher than the pharmacopoeia method,with less time and high recovery rate. The ROC curve analysis showed that there was no significant difference of contents of astragaloside Ⅳ between the top grade of Shanxi wild-simulated Astragali Radix top and the first grade of Gansu cultivated Astragali Radix. The contents of astragaloside Ⅳ in the second,third and fourth grade of Shanxi wild-simulated Astragali Radix was significantly higher than those of produced from Gansu.There was a significant negative correlation between the contents of astragaloside Ⅳ and grade in Shanxi Astragali Radix. While there was no correlation for Gansu Astragali Radix. This study provided the basis for the quality grade standard of Astragali Radix.

[~1H NMR fingerprints of Huangqi injection solution].

The study established the 1H NMR-based fingerprinting and analyzed 8 batches of Huangqi injection solution.1H NMR-based fingerprinting of both primary and secondary metabolites of Huangqi injection were established, and the 1H-1H chemical shift correlation spectroscopy (COSY) and 1H-13C chemical shift correlation spectroscopy (HSQC) were used to identify the chemical components in Huangqi injection solution. Coupled with similarity analysis and relative content determination,8 batches of Huangqi injection solution were analyzed. Twenty-five metabolites (both primary and secondary) were identified, and the significant differences were found in the chemical composition among these Huangqi samples. The content and content variation of the primary metabolites were much higher than those of the secondary metabolites, which was the major cause of the uniformity of the Huangqi injections. The results on the quality variations of Huangqi injections in this study will serve as a basis for improving the quality control.

[Thinking on development of Shanxi Astragali Radix industry].

Shanxi, a traditional production area to produce genuine Astragali Radix of high quality, has experienced major changes in the pattern of resources. This area once accounted for half of Astragali Radix industry, but now only serves as the largest supply area of traditional wild Astragali Radix. Furthermore, the strategic position of Shanxi Astragali Radix industry will become more prominent and more important to economic and social development in face of the diversity of market demands, especially for the strong demands of high-end Astragali Radix. In addition, Astragalus industry involves the simultaneous development of the first, second and tertiary industries in many areas, and it is typical and representative in the traditional Chinese medicine industry development. However, the application and industrial development of Shanxi Astragali Radix have been restricted due to the problems such as blind promotion of transplanting cultivation technology, and lack of science and technology including efficacy investigation, safety evaluation, standardization and controllability studies. Therefore, we would analyze the production history, resource structure, the current situation and progress of industry development, scientific research foundation and existing problem in this paper, and put forward countermeasures for development and technical innovation in order to make Astragali Radix industry bigger and stronger through innovation-driven and make benefits for demos. This thought provides a reference for the exploratory development of other large varieties of Chinese medicinal materials.

Comparison of Two Different Astragali Radix by a ¹H NMR-Based Metabolomic Approach.

Astragali Radix (AR) is a commonly used herbal drug in traditional chinese medicine and is widely used for the treatment of diabetes, cardiovascular diseases, nephropathy, and neuropathy. The main source of AR in China is the dried root of Astragalus membranaceus var. mongholicus (Bge.) Hsiao, and both cultivated and wild ARs are used clinically. A systematic comparison of cultivated AR (GS-AR) and wild AR (SX-AR) should be performed to ensure the clinical efficacy and safety. In this study, the chemical composition of the two different ARs, which were collected in the Shanxi (wild) and Gansu (cultivated) provinces, were compared by NMR-based metabolic fingerprint coupled with multivariate analysis. The SX-AR- and GS-AR-induced metabolic changes in the endogenous metabolites in mice were also compared. The results showed that SX-AR and GS-AR differed significantly not only in the primary metabolites but also in the secondary metabolites. However, alterations among the endogenous metabolites in the serum, lung, liver, and spleen were relatively small. This study provided a novel and valuable method for the evaluation of the consistency and diversity of herbal drugs, and further studies should be conducted on the difference in polysaccharides as well as the biological effects between the two kinds of AR.

[UPLC/Q-TOF MS and NMR plant metabolomics approach in studying the effect of growth year on the quality of Polygala tenuifolia].

Growth year is one of the important factors for the quality of Polygala tenufolia. In this study, primary metabolites and secondary metabolites were compared in 1, 2 and 3 years old P. tenufolia cultivated in Shaanxi Heyang. The samples were subjected to ultra-high performance liquid chromatography (UPLC)-quadrupole time-of-flight mass spectrometry (Q-TOF MS) and nuclear magnetic resonance (NMR) analysis, and the obtained data were analyzed using principal component analysis (PCA) and other statistical analysis methods. In addition, content and correlation of different metabolites were also calculated. The results showed no significance between main component contents in 2 year-old and 3 year-old P. Tenufolia, but 1 year-old was statistically different. The contents of primary metabolites, such as fructose, sucrose, and choline increased as time goes on, while glycine and raffinose decreased. The contents of secondary metabolites, such as onjisaponin Fg, polygalasaponin XXVIII, polygalasaponin XXXII increased, while polygalaxanthone III and parts of oligosaccharide multi-ester including tenuifoliose A, tenuifoliose C, tenuifoliose C2 and tenuifoliose H decreased with the extension of the growth years. Growth years has important impact on the quality of P. tenuifolia and the existing growing years of commodity P. tenuifolia have its scientific evidence. This study supplied a new method for the quality evaluation of Chinese medicinal materials.

[The Role of Leptin in Cognitive Development During Aging].

Brain aging is accompanied by alternations of brain structure, functions and the cognitive impairment. With respect to cognitive decline, the elderly population is far from homogeneous, as well as heterogeneous, which presents successful aging, normal aging, mild cognitive impairment and Alzheimer's disease. Studies demonstrated that higher serum leptin levels are associated with normal cognition in older adults without significant neurological conditions, while it is lower in most mild cognitive impairment patients. Leptin can improve cognitive disorders and referred to as a potential cognitive enhancer. Therefore, low level of leptin plays an significant role in cognitive impairment development in elderly people.

Chemokine fractalkine attenuates overactivation and apoptosis of BV-2 microglial cells induced by extracellular ATP.

Microglia, the resident macrophages of the central nervous system (CNS), are activated by a myriad of signaling molecules including ATP, an excitatory neurotransmitter and neuron-glial signal with both neuroprotective and neurotoxic effects. The "microglial dysfunction hypothesis" of neurodegeneration posits that overactivated microglia have a reduced neuroprotective capacity and instead promote neurotoxicity. The chemokine fractalkine (FKN), one of only two chemokines constitutively expressed in the CNS, is neuroprotective in several in vivo and in vitro models of CNS pathology. It is possible, but not yet demonstrated, that high ATP concentrations induce microglial overactivation and apoptosis while FKN reduces ATP-mediated microglial overactivation and cytotoxicity. In the current study, we examined the effects of FKN on ATP-induced microglial apoptosis and the underlying mechanisms in the BV-2 microglial cell line. Exposure to ATP induced a dose-dependent reduction in BV-2 cell viability. Prolonged exposure to a high ATP concentration (3 mM for 2 h) transformed ramified (quiescent) BV-2 cells to the amoebic state, induced apoptosis, and reduced Akt phosphorylation. Pretreatment with FKN significantly inhibited ATP-induced microglial apoptosis and transformed amoebic microglia to ramified quiescent cells. These protective effects were blocked by chemical inhibition of PI3 K, strongly implicating the PI3 K/Akt signaling pathway in FKN-mediated protection of BV-2 cells from cytotoxic ATP concentrations. Prevention of ATP-induced microglial overactivation and apoptosis may enhance the neuroprotective capacity of these cells against both acute insults and chronic CNS diseases.

Plasticity at axon initial segment of hippocampal CA3 neurons in rat after status epilepticus induced by lithium-pilocarpine.

BACKGROUND: The axon initial segment (AIS) is a specialized membrane region in the axon of neurons wherein numerous specific voltage-gated sodium channels (VGSCs) are clustered and action potentials are initiated. The AIS is currently considered as a new plastic hotspot. METHODS: We investigated the alterations in Nav1.6 (SCN8A) and its adapter protein ankyrin G in the AIS of the hippocampal cornu ammonis 3 (CA3) pyramidal cells of rat after status epilepticus induced by lithium-pilocarpine (PISE). RESULTS: Nav1.6 and ankyrin G were colocalized in the AIS of hippocampal CA3 pyramidal neurons. Compared with the control group, the protein and mRNA expression of Nav1.6 increased within 24 h and 60 days after PISE. By contrast, ankyrin G protein expression decreased slightly within 24 h but increased within 60 days, whereas ankyrin G mRNA increased within 24 h and 60 days after PISE. However, the protein and mRNA expression levels of Nav1.6 and ankyrin G within 7 days after PISE did not differ significantly with those of the control. CONCLUSIONS: Nav1.6 and ankyrin G may participate in the plastic changes in the AIS of hippocampus CA3 neurons after PISE and play potential roles in epileptogenesis by regulating neuronal excitability.

[Study on CO2 measurement using tunable multi-mode diode laser absorption spectroscopy].

Tunable diode laser absorption spectroscopy (TDLAS) technology is a kind of fast time response, large-range, continuous on-line monitoring gas detection technique. It is the mainstream technology of gas detection. In this paper the multimode laser diode was used as light source. Multi-mode laser combined with correlation spectroscopy can improve the test reliability and stability. It can also conquer the problem of the central wavelength change of the single mode diode laser due to thermal or mechanical fluctuations in durable working process. A FP laser was used as the light source in this research. A multi-mode diode laser system based on correlation spectroscopy and wavelength modulation spectroscopy (TMDL-COSPEC-WMS) was used to measure carbon dioxide in ambient air around 1 570 nm. The carbon dioxide concentrations were derived from the relationship between the normalized WMS-2f signal peak heights of the measurement and reference signals which selected based on high signal to noise ratio and correlation coefficient. All measurements were performed with controlled carbon dioxide and nitrogen mixtures in which carbon dioxide concentrations range from 0. 6% to 30%. The calculation results showed that there was a high linear relationship between the measured and actual carbon dioxide concentration, the linearity was 0. 998 7 and the fitted slope was 1. 061+/-0. 016 8 respectively over the tested range. A detection limit of 335 ppm m was achieved. The standard deviation of 0. 036 7% was achieved using 20 successive measurements with each measurement time taking approximately 10 s during 20 minutes, which demonstrated good stability of the system. Good agreements between the measurements of the system and actual values confirm the accuracy and potential utility of the system for carbon dioxide detection.

Vasoconstrictor Agent Administration as a Risk Factor for Pressure Injury Development in Intensive Care Unit Patients: A Systematic Review and Meta-Analysis.

Significance: Pressure injury (PI) is a common critical presentation in intensive care units (ICU) and is an important clinical concern in critical care settings. Some developing data support the vasoconstrictor agent administration as a potential risk factor; however, synthesis of available evidence has not been completed. Recent Advances: Comprehensive tactics were employed to search electronic databases PubMed, Web of Science, and Ovid Embase for data on vasoconstrictor agent administration associated with PI in ICU patients. Extraction was limited to studies that matched the inclusion criteria. The pooled odds ratio and 95% confidence intervals (95% CI) were calculated for dichotomous outcomes. Critical Issues: Twenty-six studies were included, involving 50,192 patients who matched the selection criteria. Around 5.8% of patients (2,523/43,210) got PI in total. PI occurred in 10.9% (1,496/13,675) of the vasoconstrictor agent administration population and 3.5% (1,027/29,503) of the drug-free population. The pooled unadjusted odds ratio was 2.83 (95% CI = 2.21-3.64, p < 0.001). The adjusted odds ratio was 1.83 (95% CI = 1.26-2.68, p = 0.002). Subgroup analysis and meta-regression found that the risk of PI did not vary with research design, time of occurrence, patient age, or male proportion. Future Directions: Vasoconstrictor agent administration raised the risk of PI in critical care patients by nearly twofold. More emphasis should be placed on the timely prevention of PI in patients receiving vasoconstrictor agent administration in the ICU.

The bound polyphenols of foxtail millet (Setaria italica) inner shell inhibit breast cancer by promoting lipid accumulation-induced autophagic death.

Foxtail millet is a traditional excellent crop with high nutritional value in the world, belong to cereals. The bran of foxtail millet is rich in polyphenol that has antioxidant, anti-inflammatory, and anti-tumorigenic effects. Previously, we extracted bound polyphenols from the inner shell of foxtail millet bran (BPIS). Here, we report that BPIS specifically induced breast cancer cell death and elevated the autophagy level simultaneously. The addition of an autophagy inhibitor blocked BPIS-induced breast cancer cell death, indicating that excessive autophagy induced cell death. Furthermore, oil red O and BODIPY staining also confirmed that lipids, which are important inducers of autophagy, accumulated in breast cancer cells treated with BPIS. Lipidomics research revealed that glycerophospholipids were the main accumulated lipids induced by BPIS. Further study showed that elevated PCYT1A expression was responsible for glycerophospholipid accumulation, and BPIS contained ferulic acid and p-coumaric acid, which induced PCYT1A expression and breast cancer cell death. Collectively, our results revealed that BPIS resulted in autophagic death by enhancing lipid accumulation in breast cancer cells, and BPIS contains ferulic acid and p-coumaric acid, which provided new insights into developing nutraceuticals and drugs for breast cancer patients.

AQP4 Aggravates Cognitive Impairment in Sepsis-Associated Encephalopathy through Inhibiting Nav 1.6-Mediated Astrocyte Autophagy.

The pathology of sepsis-associated encephalopathy (SAE) is related to astrocyte-inflammation associated with aquaporin-4 (AQP4). The aim here is to investigate the effects of AQP4 associated with SAE and reveal its underlying mechanism causing cognitive impairment. The in vivo experimental results reveal that AQP4 in peripheral blood of patients with SAE is up-regulated, also the cortical and hippocampal tissue of cecal ligation and perforation (CLP) mouse brain has significant rise in AQP4. Furthermore, the data suggest that AQP4 deletion could attenuate learning and memory impairment, attributing to activation of astrocytic autophagy, inactivation of astrocyte and downregulate the expression of proinflammatory cytokines induced by CLP or lipopolysaccharide (LPS). Furthermore, the activation effect of AQP4 knockout on CLP or LPS-induced PPAR-γ inhibiting in astrocyte is related to intracellular Ca2+ level and sodium channel activity. Learning and memory impairment in SAE mouse model are attenuated by AQP4 knockout through activating autophagy, inhibiting neuroinflammation leading to neuroprotection via down-regulation of Nav 1.6 channels in the astrocytes. This results in the reduction of Ca2+ accumulation in the cell cytosol furthermore activating the inhibition of PPAR-γ signal transduction pathway in astrocytes.

[Silica induced α-SMA expression in HBE cell line by targeting the PI3K/Akt pathway].

OBJECTIVE: To explore the role of the phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) pathway in silica-induced α-SMA (α smooth muscle actin) expression in HEB (human bronchial epithelial) cell. METHODS: The cultured HBE cells were divided into 5 groups: control, silica, PI3K inhibitor (Ly294002), both PI3K inhibitor (Ly294002) and silica at the same time and the inhibitor 24 h ahead of silica. The final concentrations of PI3K inhibitor and silica were 10 µmol/L and 100 µg/ml, respectively. Western blots were used to detect protein expressions of Akt, p-Akt, TGF-ß and α-SMA. The location and expression of α-SMA were measured by immunofluorescence assay. RESULTS: HBE cell line exposed to silica can induce Akt phosphorylation, in which expressions of p-Akt were up regulated 1 times at 48 and the highest at 72 h. The expressions of TGFß increased remarkably at 12 h and the peak at 48 h after silica exposure, while the expressions of α-SMA increased at 24 h and the highest at 72 h. However, the PI3K inhibitor (Ly294002) significantly down regulated α-SMA expression. When the cell line exposed to the PI3K inhibitor ahead of silica 24 h, the expressions of p-Akt and α-SMA were more remarkably down regulated which were decreased 1.5 times and 7.6 times respectively compare to silica exposure group. But no significant changes were found for TGFß expressions. The immunofluorescence assay showed that silica can induce α-SMA expression, which located in cytoplasma, and PI3K inhibitor can decrease the expression. CONCLUSIONS: Silica induced α-SMA expression in HBE cell line is by targeting the PI3K/Akt pathway and PI3K inhibitor can repress α-SMA expression.

LncRNA NEAT1 alleviates ischemic stroke via transcriptional inhibition of NLRP3 mediated by the miR­10b­5p/BCL6 axis.

Cerebral ischemic stroke (CIS) is a significant cause of disability and death. Inflammation usually occurs after CIS and accelerates cellular damage. NLRP3 plays a key role in the formation of CIS­associated inflammasome. Understanding how NLRP3 is regulated bears great importance. We hypothesized that lncRNA NEAT1 can downregulate NLRP3 expression by regulating the miR­10b­5p/BCL6 axis, and thus regulate microglia­driven inflammation. The expression of NEAT1 was analyzed in CIS patients and an in vitro model of oxygen and glucose deprivation/re­oxygenation (OGD/R). We assessed the levels of pro­inflammatory cytokines IL­18 and IL­1ß with ELISA. Interactions between NEAT1/miR­10b­5p and miR­10b­5p/BCL6 were determined by luciferase assay. The interaction of BCL6 and NLRP3 was identified by ChIP; RNA, and protein levels were evaluated by qRT­PCR and western blot, respectively. We found that NEAT1 level was decreased in CIS patients and OGD/R treated cells. OGD/R exerted pro­inflammasome effects by increasing the expression of inflammasome­associated proteins and ROS and malondialdehyde (MDA) while inhibiting SOD production. This effect was partially antagonized by NEAT1. We bioinformatically identified interactions between NEAT1/miR­10b­5p, BCL6/miR­10b­5p, and NLRP3­promoter/BCL6, and validated them by luciferase assay, qRT­PCR, and ChIP. NEAT1 inhibited miR­10b­5p and upregulated BCL6 by ceRNA mechanism and alleviated OGD/R induced cell damage. We also proved that BCL6 was a repressive transcription factor in the regulation of NLRP3 expression. Thus, lncRNA NEAT1 inhibited inflammasome activation by NLRP3 in microglia via the NEAT1/ miR­10b­5p/BCL6/NLRP3 regulatory axis, which alleviated deleterious outcomes of ischemic stroke.

Relationship Between the Structure and Immune Activity of Components From the Active Polysaccharides APS-II of Astragali Radix by Enzymolysis of Endo α-1,4-Glucanase.

Astragali Radix polysaccharides (APSs) have a wide range of biological activities. Our preliminary experiment showed that APS-Ⅱ (10 kDa) was the main immunologically active component of APSs. However, the characteristic structure related to activity of APS-Ⅱ needs further verification and clarification. In this study, APS-II was degraded by endo α-1,4-glucosidase. The degraded products with different degrees of polymerization [1-3 (P1), 3-6 (P2), 7-14 (P3), and 10-18 (P4)] were obtained using a polyacrylamide gel chromatography column. The structural features of the different products were characterized by HPGPC, monosaccharide composition, Fourier transform infrared spectrum, GC-MS, nuclear magnetic resonance, and UPLC-ESI-QTOF-MS analysis. Specific immune and non-specific immune cell tests were used to identify the most immunogenic fractions of the products. The backbone of P4 was speculated to be α-D-1,4-linked glucans and rich in C2 (25.34%) and C6 (34.54%) branches. Immune screening experiments indicated that the activity of P4 was better than that of APS-II and the other three components. In this research, the relationship between the structure of APS-Ⅱ and the immune activity from the degradation level of polysaccharides was studied, laying a foundation for the quality control and product development of APSs.

Reducing Nav1.6 expression attenuates the pathogenesis of Alzheimer's disease by suppressing BACE1 transcription.

Aberrant increases in neuronal network excitability may contribute to cognitive deficits in Alzheimer's disease (AD). However, the mechanisms underlying hyperexcitability of neurons are not fully understood. Voltage-gated sodium channels (VGSC or Nav), which are involved in the formation of excitable cell's action potential and can directly influence the excitability of neural networks, have been implicated in AD-related abnormal neuronal hyperactivity and higher incidence of spontaneous non-convulsive seizures. Here, we have shown that the reduction of VGSC α-subunit Nav1.6 (by injecting adeno-associated virus (AAV) with short hairpin RNA (shRNA) into the hippocampus) rescues cognitive impairments and attenuates synaptic deficits in APP/PS1 transgenic mice. Concurrently, amyloid plaques in the hippocampus and levels of soluble Aß are significantly reduced. Interfering with Nav1.6 reduces the transcription level of ß-site APP-cleaving enzyme 1 (BACE1), which is Aß-dependent. In the presence of Aß oligomers, knockdown of Nav1.6 reduces intracellular calcium overload by suppressing reverse sodium-calcium exchange channel, consequently increasing inactive NFAT1 (the nuclear factor of activated T cells) levels and thus reducing BACE1 transcription. This mechanism leads to a reduction in the levels of Aß in APP/PS1 transgenic mice, alleviates synaptic loss, improves learning and memory disorders in APP/PS1 mice after downregulating Nav1.6 in the hippocampus. Our study offers a new potential therapeutic strategy to counteract hippocampal hyperexcitability and subsequently rescue cognitive deficits in AD by selective blockade of Nav1.6 overexpression and/or hyperactivity.