Fructus mume extracts alleviate cognitive impairments in 5XFAD transgenic mice

Metabolomics, E-tongue and HS-SPME-GC-MS reveal the smoking process of Prunus mume: Changes in flavor and chemical compositions

Smoked Prunus mume (SPM), known as Wumei, experiences remarkable alterations in flavor and chemical composition. However, no research has reported on the smoking process. In this study, the changes of flavor and chemical compositions were analyzed via E-tongue, metabolomics, and HS-SPME-GC-MS during the smoking process. Results showed that significant changes in the basic parameters and electronic sense were observed during the smoking process. 85 volatile organic compounds (VOCs) were identified, and 124 metabolites were significantly differentially regulated during the smoking process. Metabolic pathway analysis showed that 20 pathways in SPM, especially phenylpropanoid biosynthesis, are related to smoking process. A number of key substances were identified by Mantel test that may have caused the electrosensory changes in SPM. These findings revealed that the changes characterization of flavor and chemical compositions in SPM during the smoking process, which will help to better understand the formation mechanism of flavor and metabolites.

Increased expression of mesencephalic astrocyte-derived neurotrophic factor (MANF) contributes to synapse loss in Alzheimer's disease

BACKGROUND

The activation of endoplasmic reticulum (ER) stress is an early pathological hallmark of Alzheimer's disease (AD) brain, but how ER stress contributes to the onset and development of AD remains poorly characterized. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a non-canonical neurotrophic factor and an ER stress inducible protein. Previous studies reported that MANF is increased in the brains of both pre-symptomatic and symptomatic AD patients, but the consequence of the early rise in MANF protein is unknown.

METHODS

We examined the expression of MANF in the brain of AD mouse models at different pathological stages. Through behavioral, electrophysiological, and neuropathological analyses, we assessed the level of synaptic dysfunctions in the MANF transgenic mouse model which overexpresses MANF in the brain and in wild type (WT) mice with MANF overexpression in the hippocampus. Using proteomic and transcriptomic screening, we identified and validated the molecular mechanism underlying the effects of MANF on synaptic function.

RESULTS

We found that increased expression of MANF correlates with synapse loss in the hippocampus of AD mice. The ectopic expression of MANF in mice via transgenic or viral approaches causes synapse loss and defects in learning and memory. We also identified that MANF interacts with ELAV like RNA-binding protein 2 (ELAVL2) and affects its binding to RNA transcripts that are involved in synaptic functions. Increasing or decreasing MANF expression in the hippocampus of AD mice exacerbates or ameliorates the behavioral deficits and synaptic pathology, respectively.

CONCLUSIONS

Our study established MANF as a mechanistic link between ER stress and synapse loss in AD and hinted at MANF as a therapeutic target in AD treatment.

Multi-component pharmacokinetic study of prunus mume fructus extract after oral administration in rats using UPLC-MS/MS

Prunus mume fructus (MF) is used in traditional Chinese medicine and food, as it exerts pharmacological effects, such as antibacterial, antioxidant, antitumour, thirst-relieving, and antidiarrheal effects. In the present study, a reliable and sensitive ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous determination of 16 prototype components (L-(-)-malic acid, 3,4-dihydroxybenzaldehyde, protocatechuic acid, vanillic acid, caffeic acid, D-(-)-quinic acid, citric acid, ferulic acid, syringic acid, cryptochlorogenic acid, neochlorogenic acid, chlorogenic acid, amygdalin, maslinic acid, corosolic acid, and rutin) in rat plasma after oral administration of the MF extract. Plasma samples were prepared via protein precipitation using acetonitrile. The 16 components were separated on an ACQUITY UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm) with a gradient mobile phase system of methanol and 0.1% (v/v) formic acid aqueous solution at a flow rate of 0.3 ml/min. All components were quantitated using Agilent Jet Stream electrospray ionisation in negative ion mode. The intra-day and inter-day accuracies ranged from-9.4 to 9.4%, and the precision of the analytes was less than 14.8%. The extraction recovery rate of the analytes ranged from 63.59 to 109.44% and the matrix effects ranged from 49.25 to 109.28%. Stability studies proved that the analytes were stable under the tested conditions, with a relative standard deviation lower than 13.7%. Hence, the developed method was successfully applied to evaluate the pharmacokinetics of 16 components in the MF extract after oral administration in rats using UPLC-MS/MS.

Fructus Mume (Wu Mei) Attenuates Acetic Acid-Induced Ulcerative Colitis by Regulating Inflammatory Cytokine, Reactive Oxygen Species, and Neuropeptide Levels in Model Rats

Ulcerative colitis (UC) is a chronic idiopathic inflammatory disorder of the large intestine. Fructus mume (FM), a natural food with nutritive and pharmaceutical value, has demonstrated therapeutic efficacy against UC. In this study, we investigated the protective effects and mechanisms of FM against UC. We induced UC in rats with 4% (v/v) acetic acid (AA), orally administered 0.7 or 0.325 g/kg FM and 0.3 g/kg sulfasalazine (SASP) for 7 days, and explored the responses the drugs elicited in the rats. We assessed the general conditions of the rats by the disease active index. We evaluated colon tissue damage macroscopically and by Hematoxylin & Eosin, Alcian Blue-periodic acid-Schiff, and Masson's staining, and explored the potential mechanisms of FM on inflammation, oxidative stress, and neuropeptides by measuring TNF-α, IL-6, IL-8, IL-10, MMP9, CXCR-1, SOD, GSH-px, MDA, ROS, SIRT3, SP, VIP, ghrelin, and 5-HT. FM treatment significantly attenuated colon damage and submucosal fibrosis compared with the model. It lowered serum proinflammatory TNF-α, IL-8, and colonic MMP9 and CXCR-1, and raised serum anti-inflammatory IL-10 levels. FM upregulated the antioxidant enzymes SOD, GSH-px, and SITR3 protein but inhibited ROS and MDA production. It downregulated colonic SP, VIP, ghrelin, and 5-HT. The beneficial effects of FM might be dose dependent. Around 0.7 g/kg FM and SASP displayed similar efficacy for treating AA-induced colitis in rats. Our results provide empirical evidence that FM protects against AA-induced UC in rats via anti-inflammatory and antioxidant mechanisms, and regulates neuropeptides; thus, FM may be a promising, safe, and efficacious alternative therapy for UC, if its efficacy can be confirmed in human trials.

Peroxiredoxin 2 deletion impairs hippocampal-dependent memory via exacerbating transient ischemia-induced oxidative damage

Peroxiredoxin 2 (Prx2) regulates oxidative stress response in neuronal injury. The present study examined the effects of Prx2 deletion on transient global ischemia-induced hippocampal-dependent memory impairment. First, 20-min bilateral common carotid artery occlusion (BCCAO)-reperfusion and sham-operated control procedures were conducted in 6- or 7-month-old Prx2 knockout and wild-type mice. The cognitive status of these mice was assessed using the Morris water maze task with a hidden platform and a novel object recognition task 7 days after the 20-min BCCAO. Next, to evaluate neuronal degeneration and oxidative stress in the CA1 subregion of the hippocampus critical for learning and memory, we measured immunoreactive Fluro-jade C (FJC)-positive signals and 4-hydroxy-2-trans-nonenal (4-HNE) levels, respectively. The 20-min BCCAO induced cognitive impairments and increased the intensity of FJC-positive signals and 4-HNE levels of CA1 in Prx2 knockout mice but not in wild-type mice. These results suggest that Prx2 deficiency reduces resilience to transient global ischemia.

Long-term caffeine treatment of Alzheimer mouse models ameliorates behavioural deficits and neuron loss and promotes cellular and molecular markers of neurogenesis

Epidemiological studies indicate that the consumption of caffeine, the most commonly ingested psychoactive substance found in coffee, tea or soft drinks, reduces the risk of developing Alzheimer’s disease (AD). Previous treatment studies with transgenic AD mouse models reported a reduced amyloid plaque load and an amelioration of behavioral deficits. It has been further shown that moderate doses of caffeine have the potential to attenuate the health burden in preclinical mouse models of a variety of brain disorders (reviewed in Cunha in J Neurochem 139:1019–1055, 2016). In the current study, we assessed whether long-term caffeine consumption affected hippocampal neuron loss and associated behavioral deficits in the Tg4-42 mouse model of AD. Treatment over a 4-month period reduced hippocampal neuron loss, rescued learning and memory deficits, and ameliorated impaired neurogenesis. Neuron-specific RNA sequencing analysis in the hippocampus revealed an altered expression profile distinguished by the up-regulation of genes linked to synaptic function and processes, and to neural progenitor proliferation. Treatment of 5xFAD mice, which develop prominent amyloid pathology, with the same paradigm also rescued behavioral deficits but did not affect extracellular amyloid-β (Aβ) levels or amyloid precursor protein (APP) processing. These findings challenge previous assumptions that caffeine is anti-amyloidogenic and indicate that the promotion of neurogenesis might play a role in its beneficial effects.

Evaluation of the Therapeutic Effect of Lycoramine on Alzheimer's Disease in Mouse Model

BACKGROUND

Alzheimer's disease is one of the leading health problems characterized by the accumulation of Aβ and hyperphosphorylated tau that account for the senile plaque formations causing extensive cognitive decline. Many of the clinical diagnoses of Alzheimer's disease are made in the late stages, when the pathological changes have already progressed.

OBJECTIVE

The objective of this study is to evaluate the promising therapeutic effects of a natural compound, lycoramine, which has been shown to have therapeutic potential in several studies and to understand its mechanism of action on the molecular level via differential protein expression analyses.

METHODS

Lycoramine and galantamine, an FDA approved drug used in the treatment of mild to moderate AD, were administered to 12 month-old 5xFAD mice. Effects of the compounds were investigated by Morris water maze, immunohistochemistry and label- free differential protein expression analyses.

RESULTS

Here we demonstrated the reversal of cognitive decline via behavioral testing and the clearance of Aβ plaques. Proteomics analysis provided in-depth information on the statistically significant protein perturbations in the cortex, hippocampus and cerebellum sections to hypothesize the possible clearance mechanisms of the plaque formation and the molecular mechanism of the reversal of cognitive decline in a transgenic mouse model. Bioinformatics analyses showed altered molecular pathways that can be linked with the reversal of cognitive decline observed after lycoramine administration but not with galantamine.

CONCLUSION

Lycoramine shows therapeutic potential to halt and reverse cognitive decline at the late stages of disease progression, and holds great promise for the treatment of Alzheimer's disease.

Comprehensive Review of Phytochemical Constituents, Pharmacological Properties, and Clinical Applications of Prunus mume

Prunus mume is one of the most ancient medicinal herbs and health foods commonly used in Asian countries. It is widely used as a constituent of many medicinal preparations and as a food ingredient for its beneficial health effects. In this review, we retrieved reports from PubMed, embase, Scopus, and SciFinder databases, to collect extensive scientific evidence on the phytochemical constituents, pharmacological properties, and clinical applications of Prunus mume. The literature review revealed that approximately 192 compounds have been isolated from different parts of the plant, and their molecular structures have been identified. The pharmacological properties of the plant, including anti-diabetic, liver-protective, antitumor, antimicrobial, antioxidant, and anti-inflammatory activities, as well as their underlying mechanisms, have been clarified by in vitro and in vivo studies. Clinical studies, although very limited, have been highlighted in this review to provide a reference for further exploration on therapeutic applications of the plant.

Quantitation of Phenolic Compounds Related to Antioxidant and Antiosteoporosis Activities in Ripe and Unripe Maesil (Prunus mume)

The fruits of Prunus mume, maesil (Rosaceae), have been widely used as a valuable source of foods and herbal medicines from ancient times in Northeast Asia. Specially, phenolic compounds of main compounds in maesil were reported to have various activities. This study aims to develop the simultaneous analytical method of nine phenolic compounds in maesil and to evaluate these compound contents in samples during the ripeness. Twenty-one species of samples and nine phenolic compounds were used for this study. In results, compounds 1–9 contents in unripe fruits were 0.16∼1.81 mg/g. However, these compounds in ripe samples were 0.09∼1.66 mg/g. Compounds 1–9 contents in ripe fruits were generally reduced rather than those in unripe fruits. Otherwise, the contents of compounds 2, 5, 8, and 9 in seed part were relatively higher than those in flesh part. In contrast, contents of compounds 1, 3, and 7 in flesh part were relatively higher than those in seed part. Generally, the contents of compounds 1–9 in unripe fruits were higher than those in ripe fruits. However, the contents of compounds 1–9 in each part (seed and fresh) of fruits were different according to species of compounds. It indicates that the selection of harvesting time and process part of fruits as the source of foods and medicines is important.

Comparative Analysis of Free Amino Acids and Nucleosides in Different Varieties of Mume Fructus Based on Simultaneous Determination and Multivariate Statistical Analyses

Mume Fructus (MF) contains a variety of organic acids, free amino acids, and nucleoside components, and studies have not yet analyzed the relationship between the components of free amino acids and nucleosides with the varieties of MF. A rapid and sensitive method was established for simultaneous determination of 21 free amino acids and 9 nucleosides in MF by ultrafast liquid chromatography-mass spectrometry. The analysis was carried out on a Waters XBridge Amide column (100 mm × 2.1 mm, 3.5 μm) with elution by the mobile phase of 0.2% aqueous formic acid (A) and 0.2% formic acid acetonitrile (B) at a flow rate of 0.2 mL/min with 1 μL per injection. The column temperature was maintained at 30°C. The target compounds were analyzed by the positive ion multiple reaction monitoring (MRM) mode. The comprehensive evaluation of the samples was carried out by principal component analysis (PCA) and technique for order preference by similarity to an ideal solution (TOPSIS) analysis. Results showed the method could simultaneously determine 30 components in MF. The content of total analytes in six mainstream varieties was different, exhibited the order Nangao > Daqingmei > Zhaoshuimei > Yanmei > Shishengme > Baimei, and aspartic acid and adenosine were the most abundant amino acid and nucleoside. PCA and OPLS-DA could easily distinguish the samples, and 11 components could be chemical markers of sample classification. TOPSIS implied that the quality of Nangao and Daqingmei was superior to the other varieties. The results could provide a reliable basis for quality evaluation and utilisation of medicinal and edible MF.

Recognition memory impairments and amyloid-beta deposition of the retrosplenial cortex at the early stage of 5XFAD mice

Early diagnosis and treatment of AD are critical for delaying its progression. The present study, therefore, examined the cognitive status and neuropathological characteristics of 4-month-old 5X familial AD (5XFAD) transgenic (Tg) mice, as an early stage of AD animal model. The novel object recognition task was performed with retention tests at varying intervals (i.e., 10 min, 1 h, 4 h, and 24 h) to measure the retention capacity of recognition memory of 5XFAD mice. At the 4h retention interval, 5XFAD mice exhibited worse performances than non-Tg control mice. Therefore, using amyloid-beta (Aβ) 42- and 4G8-immunoreactive plaques, the accumulation of Aβ was examined in the gray and white matter of the system that was necessary for the retention of recognition memory, with a focus on the hippocampus and retrosplenial cortex. The expression of ionized calcium-binding adapter molecule-1 (Iba-1) was also examined to measure microglial activation. The immunohistological analysis of Aβ and Iba-1 revealed that the retrosplenial cortex was the most affected region in the brains of 4-month-old 5XFAD mice. These findings indicate that the cognitive and neuropathological characteristics of 4-month-old 5XFAD mice would provide a research platform for studying early diagnosis and treatment of AD.

Therapeutic Potential of AAV1-Rheb(S16H) Transduction Against Alzheimer's Disease

We recently reported that adeno-associated virus serotype 1-constitutively active Ras homolog enriched in brain [AAV1-Rheb(S16H)] transduction of hippocampal neurons could induce neuron-astroglia interactions in the rat hippocampus in vivo, resulting in neuroprotection. However, it remains uncertain whether AAV1-Rheb(S16H) transduction induces neurotrophic effects and preserves the cognitive memory in an animal model of Alzheimer’s disease (AD) with characteristic phenotypic features, such as β-amyloid (Aβ) accumulation and cognitive impairments. To assess the therapeutic potential of Rheb(S16H) in AD, we have examined the beneficial effects of AAV1-Rheb(S16H) administration in the 5XFAD mouse model. Rheb(S16H) transduction of hippocampal neurons in the 5XFAD mice increased the levels of neurotrophic signaling molecules, including brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF), and their corresponding receptors, tropomyosin receptor kinase B (TrkB) and CNTF receptor α subunit (CNTFRα), respectively. In addition, Rheb(S16H) transduction inhibited Aβ production and accumulation in the hippocampus of 5XFAD mice and protected the decline of long-term potentiation (LTP), resulting in the prevention of cognitive impairments, which was demonstrated using novel object recognition testing. These results indicate that Rheb(S16H) transduction of hippocampal neurons may have therapeutic potential in AD by inhibiting Aβ accumulation and preserving LTP associated with cognitive memory.

Mumefural Ameliorates Cognitive Impairment in Chronic Cerebral Hypoperfusion via Regulating the Septohippocampal Cholinergic System and Neuroinflammation

Chronic cerebral hypoperfusion (CCH) causes cognitive impairment and neurogenic inflammation by reducing blood flow. We previously showed that Fructus mume (F. mume) improves cognitive impairment and inhibits neuroinflammation in a CCH rat model. One of the components of F. mume, Mumefural (MF), is known to improve blood flow and inhibit platelet aggregation. Whether MF affects cerebral and cognitive function remains unclear. We investigated the effects of MF on cognitive impairment and neurological function-related protein expression in the rat CCH model, established by bilateral common carotid arterial occlusion (BCCAo). Three weeks after BCCAo, MF (20, 40, or 80 mg/kg) was orally administrated once a day for 42 days. Using Morris water maze assessment, MF treatment significantly improved cognitive impairment. MF treatment also inhibited cholinergic system dysfunction, attenuated choline acetyltransferase-positive cholinergic neuron loss, and regulated cholinergic system-related protein expressions in the basal forebrain and hippocampus. MF also inhibited myelin basic protein degradation and increased the hippocampal expression of synaptic markers and cognition-related proteins. Moreover, MF reduced neuroinflammation, inhibited gliosis, and attenuated the activation of P2X7 receptor, TLR4/MyD88, NLRP3, and NF-κB. This study indicates that MF ameliorates cognitive impairment in BCCAo rats by enhancing neurological function and inhibiting neuroinflammation.

Efficacy of traditional Chinese medication Tangminling pill in Chinese patients with type 2 diabetes

The morbidity of type 2 diabetes mellitus (T2DM) has been increasing rapidly worldwide. Tangminling pill, consisting of ten Chinese herbal medications, is usually prescribed for T2DM in mainland China. Whether treatment with Tangminling can improve clinical outcomes of T2DM patients was still debated. Four studies comparing Tangminling vs. placebo treatment in T2DM patients were included and 767 T2DM patients were enrolled in our analyses. Tangminling treatment exhibited better efficacy than placebo in reducing hemoglobin A1c (HbA1c) (1.11 vs. 0.32%; pooled weighted mean difference [WMD]: 0.80; 95% confidence interval [CI]: 0.65–0.96; P<0.001), fasting plasma glucose (0.82 vs. −0.40 mM; WMD: 1.10; 95% CI: 0.56–1.64; P<0.001), 2-h postprandial glucose (2-hr PG) (2.81 vs. 1.11 mM; WMD: 1.80; 95% CI: 1.72–1.88; P<0.001), homeostatic model assessment-β level (4.28 vs. 0.41; WMD: 0.44; 95% CI: 0.27–0.61; P<0.001), waist circumference (WC) (1.04 vs. 0.36 cm; WMD: 0.78; 95% CI: 0.37–1.19; P<0.001) and body weight index (0.37 vs. 0.11 kg/m²; WMD: 0.30; 95% CI: −0.00 to 0.61; P=0.05). Tangminling pill might reduce glucose level and body weight and improve β-cell function in T2DM patients. Our study highlights the important role of Tangminling pill in the management of T2DM.

Assessment of Cognitive Phenotyping in Inbred, Genetically Modified Mice, and Transgenic Mouse Models of Alzheimer's Disease

Genetically modified mouse models are being used predominantly to understand brain functions and diseases. Well-designed and controlled behavioral analyses of genetically modified mice have successfully led to the identification of gene functions, understanding of brain diseases, and development of treatments. Recently, complex and higher cognitive functions have been examined in mice with genetic mutations. Therefore, research strategies for cognitive phenotyping should be sophisticated and evolve to convey the exact meaning of the findings and provide robust translational tools for testing hypotheses and developing treatments. This review addresses issues of experimental design and discusses studies that have examined cognitive function using mouse strain differences, genetically modified mice, and transgenic mice for Alzheimer's disease.

Intranasal telmisartan ameliorates brain pathology in five familial Alzheimer's disease mice

The renin-angiotensin system (RAS) is a major circulative system engaged in homeostasis modulation. Angiotensin II (Ang II) serves as its main effector hormone upon binding to its primary receptor, Ang II receptor type 1 (AT₁R). It is well established that an intrinsic independent brain RAS exists. Abnormal AT₁R activation both in the periphery and in the brain probably contributes to the development of Alzheimer's disease (AD) pathology that is characterized, among others, by brain inflammation. Moreover, treatment with drugs that block AT₁R (AT₁R blockers, ARBs) ameliorates most of the clinical risk factors leading to AD. Previously we showed that short period of intranasal treatment with telmisartan (a brain penetrating ARB) reduced brain inflammation and ameliorated amyloid burden (a component of Alzheimer's plaques) in AD transgenic mouse model. In the present study, we aimed to examine the long-term effect of intranasally administrated telmisartan on brain inflammation features including microglial activation, astrogliosis, neuronal loss and hippocampus-dependent cognition in five-familial AD mouse model (5XFAD). Five month of intranasal treatment with telmisartan significantly reduced amyloid burden in the cortex and hippocampus of 5XFAD mice as compared with the vehicle-treated 5XFAD group. Similar effects were also observed for CD11b staining, which is a marker for microglial accumulation. Telmisartan also significantly reduced astrogliosis and neuronal loss in the cortex of 5XFAD mice compared with the vehicle-treated group. Improved spatial acquisition of the 5XFAD mice following long-term intranasal administration of telmisartan was also observed. Taken together, our data suggest a significant role for AT1R blockage in mediating neuronal loss and cognitive behavior, possibly through regulation of amyloid burden and glial inflammation.