LW-AFC, a new formula derived from Liuwei Dihuang decoction, ameliorates behavioral and pathological deterioration via modulating the neuroendocrine-immune system in PrP-hAβPPswe/PS1ΔE9 transgenic mice

Polysaccharides from fructus corni: Extraction, purification, structural features, and biological activities

Fructus Corni, derived from the dried fruit of Cornus officinalis Sieb. Et Zucc., is widely used as a food source and Chinese herb. Fructus Corni, as an indispensable ingredient in Liuwei Dihuang decoction, tonifies the liver and kidneys. As the main component of water decoctions, Fructus Corni polysaccharides demonstrate multifaceted effects, including hypoglycemic, hypolipidemic, antioxidant, anti-aging, sexual function regulation, and anti-epileptic, The ultrasound-assisted extraction method obtained the highest yields of Fructus Corni polysaccharides. However, it has notable shortcomings and lacks further innovation. The homogeneous polysaccharides obtained from Fructus Corni are mostly neutral polysaccharides with relatively limited structure, and the mechanism of their biological activity needs to be further elucidated. In addition, different extraction, isolation and purification methods may change the molecular weight, monosaccharide composition, and biological activity of polysaccharides. Therefore, this study systematically summarized the extraction, purification, structural features, and biological activities of Fructus Corni polysaccharides. This study aimed to provide support for the ongoing development and application of Fructus Corni polysaccharides.

Structure characterisation of polysaccharides purified from Boletus aereus Bull. and its improvement on AD-like behaviours via reliving neuroinflammation in APP/PS1 mice

The water-soluble neutral polysaccharide BEP2, with a molecular weight of 26.65 kDa, was isolated from the aqueous extract obtained from the fruiting bodies of Boletus aereus Bull. BEP2 primarily comprises Gal, with specific site substitutions speculated at partial positions, such as the substitution of -OCH3 at position H-3 or the branch at position C-2 including α-L-Fucp-(1→, α-D-Manp-(1 → and α-D-Manp-(1 → 3)-α-L-Fucp-(1 → 6)-β-D-Glcp-(1→. Treatment with BEP2 significantly enhanced learning, memory, and cognitive function, while concurrently reducing the accumulation of β-amyloid and suppressing neuroinflammation within the brains of APP/PS1 mice. Based on the results of biochemical detection, gut microbiota analysis, and metabolomic profiling, we found that BEP2 significantly upregulated the abundance of two bacterial families while downregulation that of seven bacterial families within the intestinal ecosystem. Notably, the abundance of the S24-7 family was significantly increased. Treatment with BEP2 upregulated five metabolites, while downregulating three metabolites, including norepinephrine. Additionally, BEP2 decreased the levels of interleukin (IL)-1β and IL-6, regulated the activities of microglial cells and astrocytes and increased the levels of the chemokine fractalkine (CX3CL1) and its receptor on microglia (CX3CR1), as well as that of transforming growth factor (TGF)-β1. These findings confirmed the suppressive effects of BEP2 on neuroinflammation.

Di-Huang-Yin-Zi regulates P53/SLC7A11 signaling pathway to improve the mechanism of post-stroke depression

ETHNOPHARMACOLOGICAL RELEVANCE

Post-stroke depression (PSD) is a condition characterized by a profoundly depressed mood and diminished interest following a stroke. Di-Huang-Yin-Zi (DHYZ), a traditional Chinese herbal preparation, gained widespread use and shown favorable outcomes in PSD treatment. However, the combination mechanisms of this formula for PSD remain unclear.

AIM OF STUDY

This study aimed to assess the therapeutic effects of DHYZ extract on rats with PSD and further investigate its underlying mechanism.

MATERIALS AND METHODS

The active components of DHYZ extract were quantified by the high-performance liquid chromatography-ultraviolet (HPLC-UV). Neurofunctional and depressive-like behavioral tests were performed to assess the neuroprotective effects of DHYZ extract after establishing a PSD rat model. Brain tissue damage volume was assessed using TTC staining, and transmission electron microscopy (TEM) was used to observe the ultrastructural changes of neurons in the prefrontal cortex region, while cell apoptosis was evaluated through TUNEL assay in the prefrontal cortex region of the brain. The effect of DHYZ on ferroptosis markers includes Fe2+, malondialdehyde (MDA), reactive oxygen species (ROS), and glutathione (GSH) were determined in the brain tissue. Moreover, the expression of key proteins or mRNA levels of the P53/SLC7A11 signaling pathway were detected using Western blot or PCR, respectively. Additionally, P53-constructed overexpression vectors were injected to increase the level of P53. In this series of experiments, ferroptosis markers and key factors of the P53/SLC7A11 signaling pathway were evaluated.

RESULTS

DHYZ extract could increase the sucrose preference of SPT, but decrease the duration of immobility of FST and cortical infarct volume of PSD rats. A TEM study revealed that DHYZ extract improved synaptic ultrastructure in the cortical region of PSD rats. Furthermore, DHYZ treatment effectively decreased ROS and MDA levels, inhibiting the expression of ferroptosis-related markers such as Fe2+, SLC7A11, and GPX4. Additionally, DHYZ promoted the ubiquitination of P53, thus inhibiting its degradation. Notably, AAV-mediated overexpression of P53 reversed the effects of DHYZ on neuroprotection and ferroptosis inhibition in PSD rats.

CONCLUSIONS

Our results demonstrated that DHYZ extract alleviates the symptoms and enhances the functional capability of PSD rats, mainly by suppressing the ferroptosis through the P53/SLC7A11/GPX4 pathway.

The neuroprotective effects of Liuwei Dihuang medicine in the APP/PS1 mouse model are dependent on the PI3K/Akt signaling pathway

Alzheimer's disease (AD) is an age-related neurodegenerative disease that progressively impairs cognitive function and memory. The occurrence and development of Alzheimer's disease involves many processes. In response to the complex pathogenesis of AD, the Traditional Chinese medicine formula Liuwei Dihuang Pill (LWD) has been shown to improve the cognitive function of AD animal models. However, the active ingredients and mechanism of action of LWD have not been fully elucidated. In this study, network pharmacological analysis predicted 40 candidate compounds in LWD, acting on 227 potential targets, of which 185 were associated with AD. Through network pharmacological analysis, the mechanism of action of LWD therapy AD is related to the inhibition of inflammatory response, regulation of neuronal state, and autophagy. In this experiment, LWD was detected in the APP/PS1 transgenic mouse model. The objective was to observe the effects of LWD on hippocampal learning and memory ability, Aβ clearance, autophagy and inflammatory response in APP/PS1 mice. The results showed that LWD improved long-term memory and working memory in APP/PS1 mice compared with the WT group. At the same time, LWD can increase the expression of hippocampal autophagy biomarkers, reduce the precipitation of Aβ, and the activation of microglia and astrocytes. Its mechanism may be related to the regulation of the PI3K/Akt signaling pathway. Thus, we demonstrate for the first time that LWD has a neuroprotective effect on APP/PS1 mice and provide theoretical foundation for the development of a new clinical treatment for AD.

Rehmannioside A improves cognitive impairment and alleviates ferroptosis via activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway after ischemia

ETHNOPHARMACOLOGICAL RELEVANCE

Rehmannioside A is derived from Rehmannia glutinosa Libosch, which is widely used as an important ingredient in diverse traditional Chinese medicines to treat diseases caused by "kidney deficiency" such as cerebral arteriosclerosis, aging-related stroke and dementia in China. Recent studies have proved that Rehmannia glutinosa Libosch and Rehmannioside A can improve memory capability and recover nerve damage.

AIM OF THE STUDY

To investigate the effect of Rehmannioside A on cognitive impairment after ischemia in rats and SH-SY5Y cells, and further evaluate the anti-oxidative and anti-ferroptosis mechanisms.

MATERIALS AND METHODS

Differentially expressed proteins (DEPs) in patients after cerebral ischemic stroke were revealed by a RayBio protein array. Cognitive impairment model was established by middle cerebral artery occlusion and reperfusion (MCAO) 14 days in rats. Rehmannioside A was administered intraperitoneally injection at dose of 80 mg/kg. The SH-SY5Y cells were exposed to H2O2 for 24 h and treated with Rehmannioside A (80 μM) for 24 h. The neuroprotecion of Rehmannioside A were evaluated by infarct volume (TTC), neurological defects (Garcia score) and learning memory (Morris water maze test) in vivo, and cell viability (CCK-8 or LDH) in vitro. Superoxide dismutase (SOD), malondialdehyde (MDA) and myeloperoxidase (MPO) activity of rats, glutathione (GSH), oxidized glutathione (GSSG) and nicotinamide adenine dinucleotide phosphate (NADPH) of cells were detected by biochemical assay. Intracellular reactive oxygen species (ROS) were measured by DCFH-DA assay. Myeloperoxidase (MPO), PI3 kinase (PI3K), p-PI3K, Akt, p-Akt, heme oxygenase-1 (HO-1), nuclear factor-E2-related factor 2 (Nrf2), SLC7A11, glutathione peroxidase 4 (GPX4) of the cerebral cortex in rats or SH-SY5Y cells were examined by western blotting.

RESULTS

Compared with model group, the cognitive impairment and neurological deficits of Rehmannioside A group were significantly improved, and the cerebral infarction was reduced in MCAO rats. Moreover, the cell viability obviously increased and the H2O2-induced toxicity was reduced in Rehmannioside A group. Further research indicated that the expression of p-PI3K, p-Akt, nuclear Nrf2, HO-1 and SLC7A11 in Rehmannioside A group was significantly higher than model group.

CONCLUSION

Rehmannioside A has neuroprotection effect and improves cognitive impairment after cerebral ischemia by inhibiting ferroptosis and activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway. These findings provide valuable insight into the pathogenesis and therapeutic target of ischemic stroke.

Stachyose Alleviates Corticosterone-Induced Long-Term Potentiation Impairment via the Gut–Brain Axis

Stress can induce learning and memory impairment; corticosterone is often used to study the effects and mechanisms of stress in animal models. Long-term potentiation (LTP) has been widely used for tackling the mechanisms of memory. Liuwei Dihuang decoction-active fraction combination (LW-AFC) can improve stress-induced LTP and cognition impairment; stachyose is an oligosaccharide in LW-AFC. The effects and mechanisms of stachyose on stress are unknown. In this study, stachyose showed protective effects against LTP impairment by corticosterone in vivo only via intragastric administration for 7 consecutive days, but there was little effect even after direct intracerebroventricular injection; the protective effect of stachyose could be canceled by non-absorbable antibiotics (ATB) which disturbed gut flora. 16S rRNA sequencing, alpha diversity, and principal coordinate analysis (PCoA) revealed that the gut flora in corticosterone-treated mice was disturbed and stachyose could improve corticosterone-induced gut flora disturbance. Bacteroidetes were decreased and Deferribacteres were increased significantly in corticosterone-treated mice, and stachyose restored Bacteroidetes and Deferribacteres to the normal level. D-serine, a coactivator of NMDA receptors, plays an important role in synaptic plasticity and cognition. Here, corticosterone had little effect on the content of D-serine and L-serine (the precursor of D-serine), but it reduced the D-serine release-related proteins, Na⁺-independent alanine–serine–cysteine transporter-1 (ASC-1), and vesicle-associated membrane protein 2 (VAMP2) significantly in hippocampus; stachyose significantly increased ASC-1 and VAMP2 in corticosterone-treated mice, and ATB blocked stachyose’s effects on ASC-1 and VAMP2. NMDA receptors co-agonists L-serine, D-serine, and glycine significantly improved LTP impairment by corticosterone. These results indicated that stachyose might indirectly increase D-serine release through the gut–brain axis to improve LTP impairment by corticosterone in the hippocampus in vivo.

Eriodictyol ameliorates cognitive dysfunction in APP/PS1 mice by inhibiting ferroptosis via vitamin D receptor-mediated Nrf2 activation

Background

Alzheimer’s disease (AD) is the most common type of neurodegenerative disease in the contemporary era, and it is still clinically incurable. Eriodictyol, a natural flavonoid compound that is mainly present in citrus fruits and some Chinese herbal medicines, has been reported to exert anti-inflammatory, antioxidant, anticancer and neuroprotective effects. However, few studies have examined the anti-AD effect and molecular mechanism of eriodictyol.

Methods

APP/PS1 mice were treated with eriodictyol and the cognitive function of mice was assessed using behavioral tests. The level of amyloid-β (Aβ) aggregation and hyperphosphorylation of Tau in the mouse brain were detected by preforming a histological analysis and Western blotting. HT-22 cells induced by amyloid-β peptide (1–42) (Aβ_1–42) oligomers were treated with eriodictyol, after which cell viability was determined and the production of p-Tau was tested using Western blotting. Then, the characteristics of ferroptosis, including iron aggregation, lipid peroxidation and the expression of glutathione peroxidase type 4 (GPX4), were determined both in vivo and in vitro using Fe straining, Western blotting and qPCR assays. Additionally, the expression level of vitamin D receptor (VDR) and the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathway were tested using Western blotting and qPCR assays. Afterward, HT-22 cells with VDR knockout were used to explore the potential mechanisms, and the relationship between VDR and Nrf2 was further assessed by performing a coimmunoprecipitation assay and bioinformatics analysis.

Results

Eriodictyol obviously ameliorated cognitive deficits in APP/PS1 mice, and suppressed Aβ aggregation and Tau phosphorylation in the brains of APP/PS1 mice. Moreover, eriodictyol inhibited Tau hyperphosphorylation and neurotoxicity in HT-22 cells induced by Aβ_1–42 oligomer. Furthermore, eriodictyol exerted an antiferroptosis effect both in vivo and in vitro, and its mechanism may be associated with the activation of the Nrf2/HO-1 signaling pathway. Additionally, further experiments explained that the activation of Nrf2/HO-1 signaling pathway by eriodictyol treatment mediated by VDR.

Conclusions

Eriodictyol alleviated memory impairment and AD-like pathological changes by activating the Nrf2/HO-1 signaling pathway through a mechanism mediated by VDR, which provides a new possibility for the treatment of AD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00442-3.

Cognitive enhancement and neuroprotective effects of OABL, a sesquiterpene lactone in 5xFAD Alzheimer's disease mice model

Alzheimer's disease (AD) is a neurodegenerative disease in which oxidative stress and neuroinflammation were demonstrated to be associated with neuronal loss and cognitive deficits. However, there are still no specific treatments that can prevent the progression of AD. In this study, a screening of anti-inflammatory hits from 4207 natural compounds of two different molecular libraries indicated 1,6-O,O-diacetylbritannilactone (OABL), a 1,10-seco-eudesmane sesquiterpene lactone isolated from the herb Inula britannica L., exhibited strong anti-inflammatory activity in vitro as well as favorable BBB penetration property. OABL reduced LPS-induced neuroinflammation in BV-2 microglial cells as assessed by effects on the levels of inflammatory mediators including NO, PGE₂, TNF-α, iNOS, and COX-2, as well as the translocation of NF-κB. Besides, OABL also exhibited pronounced neuroprotective effects against oxytosis and ferroptosis in the rat pheochromocytoma PC12 cell line. For in vivo research, OABL (20 mg/kg B.W., i.p.) for 21 d attenuated the impairments in cognitive function observed in 6-month-old 5xFAD mice, as assessed with the Morris water maze test. OABL restored neuronal damage and postsynaptic density protein 95 (PSD95) expression in the hippocampus. OABL also significantly reduced the accumulation of amyloid plaques, the Aβ expression, the phosphorylation of Tau protein, and the expression of BACE1 in AD mice brain. In addition, OABL attenuated the overactivation of microglia and astrocytes by suppressing the expressions of inflammatory cytokines, and increased glutathione (GSH) and reduced malondialdehyde (MDA) and super oxide dismutase (SOD) levels in the 5xFAD mice brain. In conclusion, these results highlight the beneficial effects of the natural product OABL as a novel treatment with potential application for drug discovery in AD due to its pharmacological profile.

NLRP1 inflammasome involves in learning and memory impairments and neuronal damages during aging process in mice

Background

Brain aging is an important risk factor in many human diseases, such as Alzheimer’s disease (AD). The production of excess reactive oxygen species (ROS) mediated by nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) and the maturation of inflammatory cytokines caused by activation of the NOD-like receptor protein 1 (NLRP1) inflammasome play central roles in promoting brain aging. However, it is still unclear when and how the neuroinflammation appears in the brain during aging process.

Methods

In this study, we observed the alterations of learning and memory impairments, neuronal damage, NLRP1 inflammasome activation, ROS production and NOX2 expression in the young 6-month-old (6 M) mice, presenile 16 M mice, and older 20 M and 24 M mice.

Results

The results indicated that, compared to 6 M mice, the locomotor activity, learning and memory abilities were slightly decreased in 16 M mice, and were significantly decreased in 20 M and 24 M mice, especially in the 24 M mice. The pathological results also showed that there were no significant neuronal damages in 6 M and 16 M mice, while there were obvious neuronal damages in 20 M and 24 M mice, especially in the 24 M group. Consistent with the behavioral and histological changes in the older mice, the activity of β-galactosidase (β-gal), the levels of ROS and IL-1β, and the expressions of NLRP1, ASC, caspase-1, NOX2, p47phox and p22phox were significantly increased in the cortex and hippocampus in the older 20 M and 24 M mice.

Conclusion

Our study suggested that NLRP1 inflammasome activation may be closely involved in aging-related neuronal damage and may be an important target for preventing brain aging.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12993-021-00185-x.

Active Fraction Combination From Liuwei Dihuang Decoction Improves Adult Hippocampal Neurogenesis and Neurogenic Microenvironment in Cranially Irradiated Mice

Background: Cranial radiotherapy is clinically used in the treatment of brain tumours; however, the consequent cognitive and emotional dysfunctions seriously impair the life quality of patients. LW-AFC, an active fraction combination extracted from classical traditional Chinese medicine prescription Liuwei Dihuang decoction, can improve cognitive and emotional dysfunctions in many animal models; however, the protective effect of LW-AFC on cranial irradiation–induced cognitive and emotional dysfunctions has not been reported. Recent studies indicate that impairment of adult hippocampal neurogenesis (AHN) and alterations of the neurogenic microenvironment in the hippocampus constitute critical factors in cognitive and emotional dysfunctions following cranial irradiation. Here, our research further investigated the potential protective effects and mechanisms of LW-AFC on cranial irradiation–induced cognitive and emotional dysfunctions in mice.

Methods: LW-AFC (1.6 g/kg) was intragastrically administered to mice for 14 days before cranial irradiation (7 Gy γ-ray). AHN was examined by quantifying the number of proliferative neural stem cells and immature neurons in the dorsal and ventral hippocampus. The contextual fear conditioning test, open field test, and tail suspension test were used to assess cognitive and emotional functions in mice. To detect the change of the neurogenic microenvironment, colorimetry and multiplex bead analysis were performed to measure the level of oxidative stress, neurotrophic and growth factors, and inflammation in the hippocampus.

Results: LW-AFC exerted beneficial effects on the contextual fear memory, anxiety behaviour, and depression behaviour in irradiated mice. Moreover, LW-AFC increased the number of proliferative neural stem cells and immature neurons in the dorsal hippocampus, displaying a regional specificity of neurogenic response. For the neurogenic microenvironment, LW-AFC significantly increased the contents of superoxide dismutase, glutathione peroxidase, glutathione, and catalase and decreased the content of malondialdehyde in the hippocampus of irradiated mice, accompanied by the increase in brain-derived neurotrophic factor, insulin-like growth factor-1, and interleukin-4 content. Together, LW-AFC improved cognitive and emotional dysfunctions, promoted AHN preferentially in the dorsal hippocampus, and ameliorated disturbance in the neurogenic microenvironment in irradiated mice.

Conclusion: LW-AFC ameliorates cranial irradiation–induced cognitive and emotional dysfunctions, and the underlying mechanisms are mediated by promoting AHN in the dorsal hippocampus and improving the neurogenic microenvironment. LW-AFC might be a promising therapeutic agent to treat cognitive and emotional dysfunctions in patients receiving cranial radiotherapy.

Honokiol Restores Microglial Phagocytosis by Reversing Metabolic Reprogramming

BACKGROUND

Dysfunction of microglia has been increasingly recognized as a causative factor in Alzheimer's disease (AD); thus, developing medicines capable of restoring microglial functions is critically important and constitutes a promising therapeutic strategy. Honokiol is a natural neuroprotective compound extracted from Magnolia officinalis, which may play roles in AD therapy.

OBJECTIVE

This study aimed to evaluate the role and the underlying mechanisms of honokiol in microglial phagocytosis.

METHODS

MTT and flow cytometry were used to assess the cell viability and apoptosis, respectively. Phagocytic capacity, mitochondrial reactive oxygen species production, and membrane potential were evaluated using fluorescence microscopy. Seahorse XF24 extracellular flux analyzer was for cell glycolysis and oxidative phosphorylation detection. Mass spectrometry was applied for metabolites measurement. Quantitative real-time polymerase chain reaction and western blotting were performed to detect the mRNA and protein level of PPARγ and PGC1α, respectively.

RESULTS

Honokiol alleviated Aβ42-induced BV2 neurotoxicity. Honokiol promoted phagocytic efficiency of BV2 cells through reversing a metabolic switch from oxidative phosphorylation to anaerobic glycolysis and enhancing ATP production. Meanwhile, honokiol reduced mitochondrial reactive oxygen species production and elevated mitochondrial membrane potential. Moreover, honokiol increased the expression of PPARγ and PGC1α, which might play positive roles in energy metabolism and microglial phagocytosis.

CONCLUSION

In this study, honokiol was identified as an effect natural product capable of enhancing mitochondrial function thus promoting microglial phagocytic function.

Xanthohumol ameliorates memory impairment and reduces the deposition of β-amyloid in APP/PS1 mice via regulating the mTOR/LC3II and Bax/Bcl-2 signalling pathways

OBJECTIVES

Xanthohumol (XAN) is a unique component of Humulus lupulus L. and is known for its diverse biological activities. In this study, we investigated whether Xanthohumol could ameliorate memory impairment of APP/PS1 mice, and explored its potential mechanism of action.

METHODS

APP/PS1 mice were used for in vivo test and were treated with N-acetylcysteine and Xanthohumol for 2 months. Learning and memory levels were evaluated by the Morris water maze. Inflammatory and oxidative markers in serum and hippocampus and the deposition of Aβ in the hippocampus were determined. Moreover, the expression of autophagy and apoptosis proteins was also evaluated by western blot.

KEY FINDINGS

Xanthohumol significantly reduced the latency and increased the residence time of mice in the target quadrant. Additionally, Xanthohumol increased superoxide dismutase level and reduced Interleukin-6 and Interleukin-1β levels both in serum and hippocampus. Xanthohumol also significantly reduced Aβ deposition in the hippocampus and activated autophagy and anti-apoptotic signals.

CONCLUSIONS

Xanthohumol effectively ameliorates memory impairment of APP/PS1 mice by activating mTOR/LC3 and Bax/Bcl-2 signalling pathways, which provides new insight into the neuroprotective effects of Xanthohumol.

Shenzao jiannao oral liquid, an herbal formula, ameliorates cognitive impairments by rescuing neuronal death and triggering endogenous neurogenesis in AD-like mice induced by a combination of Aβ42 and scopolamine

ETHNOPHARMACOLOGICAL RELEVANCE

According to the theory of traditional Chinese medicine (TCM), Alzheimer's disease (AD) is identified as "forgetfulness" or "dementia", and is mainly caused by "kidney essence deficiency" which ultimately induces "encephala reduction". Therefore, herbal formulas possessing the efficacy of nourishing kidney essence or replenishing brain marrow are commonly served as effective strategies for AD treatment. Shenzao jiannao oral liquid (SZJN), a traditional Chinese preparation approved by the China Food and Drug Administration (CFDA), is used for the treatment of insomnia and mind fatigue at present for its efficacy of nourishing kidneys. In present study, we found that SZJN could improve cognitive function of AD-like mice.

AIMS OF STUDY

This study aims to investigate the effects of SJZN on ameliorating cognitive deficits of AD-like mouse model, and to illuminate the underlying mechanisms from the perspective of neuroprotection and neurogenesis.

MATERIALS AND METHODS

Kunming mice (28 ± 2 g) were randomly allocated into seven groups: control, sham, model, donepezil and SZJN groups (low, middle and high). The AD mouse model was established by Aβ42 combined with scopolamine. SZJN were intragastrically administrated at doses of 0.3, 1.5 and 7.5 g/kg for 28 days. Morris water maze (MWM) test was applied to determine the cognitive function. Hematoxylin eosin (HE) and Nissl staining were carried out to evaluate pathological damages in the cortex and hippocampal tissues. To explore the protective effects of SZJN on multiple pathogenic factors of AD, protein levels of Aβ42, glial fibrillary acidic protein (GFAP), Bax, Bcl-2, Caspase-3, synaptophysin (SYP), brain-derived neurotrophic factor (BDNF), and neurogenesis related proteins were assessed using Immunofluorescence (IF) and western blot analysis. In vitro, the AD cell model was established by transduction of APP_695swe genes into Neural stem cells (NSCs) isolated from the hippocampal tissues of neonatal C57BL/6 mice. Cell viability assay and neurosphere formation assay were carried out to verify the efficacy of SZJN on proliferation of NSCs.

RESULTS

Our results demonstrated that SZJN (1.5 g/kg and 7.5 g/kg) treatment significantly ameliorated cognitive deficits of AD-like mice. SZJN (7.5 g/kg) treatment significantly retarded the pathological damages including neuronal degeneration, neuronal apoptosis, Aβ peptides aggregation and reaction of astrocytes in AD-like mice. In addition, SZJN (7.5 g/kg) increased the expression of BDNF and SYP, and restored the abnormal level of MDA and SOD in the brain of AD-like mice. Furthermore, SZJN treatment for 28 days remarkably increased the proliferation of NSCs evidenced by more Nestin⁺ and BrdU⁺ cells in the hippocampal DG regions, and increased the amount of mature neurons marked by NeuN both in the cortex and hippocampal DG regions. In vitro, SZJN treatement (16, 32, 64 mg/ml) promoted the proliferation of NSCs evidenced by the increased amount and enlarged size of the neurospheres (p < 0.05).

CONCLUSIONS

Our findings indicated that SZJN could ameliorate cognitive deficits by protecting neurons from death and triggering endogenous neurogenesis. Therefore, SZJN may be considered as a promising agent to restore neuronal loss and deter the deterioration in AD patients.

The role of interleukin-33 in patients with mild cognitive impairment and Alzheimer's disease

BACKGROUND

The neuroprotective role of interleukin (IL)-33 is supported by numerous preclinical studies, but it remains uninvestigated in clinical studies of Alzheimer's disease (AD). We aimed to examine the association between human blood levels of IL-33 and cognitive preservation in amnestic mild cognitive impairment (aMCI) and AD.

METHODS

A total of 100 participants (26 controls, 35 aMCI patients, and 39 AD patients) completed two Mini-Mental State Examinations (MMSEs) over a 1-year interval. In all 100 participants at the second MMSE, we examined the plasma levels of IL-33, IL-β, IL-1 receptor agonist (IL-1RA), beta amyloid (Aβ), and tau and apolipoprotein E (ApoE) genotyping; we also performed Hopkins Verbal Learning Test, Trail Making Test, forward and backward digit span, and Clinical Dementia Rating.

RESULTS

IL-33 expression showed a positive trend among controls (1/26 = 3.8%), aMCI (9/35 = 25.7%), and AD (17/39 = 43.6%) (trend analysis: P < 0.001). Patients expressing IL-33 preserved their cognitive function compared with IL-33 non-expressing patients (1-year ΔMMSE, 0.16 ± 1.6 vs - 1.5 ± 2.6; P = 0.006). The cognitive preservation was not associated with the lower levels of Aβ, tau, and ApoE ε4, while higher levels of ApoE ε4 and phosphorylated tau were indeed associated with cognitive decline. The aMCI patients with AD conversion during study period had higher proportion of IL-33(-) than non-AD converters (90.9% vs 53.3%, P = 0.04).

CONCLUSIONS

IL-33 or its associated signaling pathways may represent a new treatment paradigm for aMCI and AD.

CA-30, an oligosaccharide fraction derived from Liuwei Dihuang decoction, ameliorates cognitive deterioration via the intestinal microbiome in the senescence-accelerated mouse prone 8 strain

Mounting evidence points to alterations in the gut microbiota-neuroendocrine immunomodulation (NIM) network that might drive Alzheimer’s Disease (AD) pathology. In previous studies, we found that Liuwei Dihuang decoction (LW) had beneficial effects on the cognitive impairments and gastrointestinal microbiota dysbiosis in an AD mouse model. In particular, CA-30 is an oligosaccharide fraction derived from LW. We sought to determine the effects of CA-30 on the composition and function of the intestinal microbiome in the senescence-accelerated mouse prone 8 (SAMP8) mouse strain, an AD mouse model. Treatment with CA-30 delayed aging processes, ameliorated cognition in SAMP8 mice. Moreover, CA-30 ameliorated abnormal NIM network in SAMP8 mice. In addition, we found that CA-30 mainly altered the abundance of four genera and 10 newborn genera. Advantageous changes in carbohydrate-active enzymes of SAMP8 mice following CA-30 treatment, especially GH85, were also noted. We further found that seven genera were significantly correlated with the NIM network and cognitive performance. CA-30 influenced the relative abundance of these intestinal microbiomes in SAMP8 mice and restored them to SAMR1 mouse levels. CA-30 ameliorated the intestinal microbiome, rebalanced the NIM network, improved the AD-like cognitive impairments in SAMP8 mice, and can thus be a potential therapeutic agent for AD.

Notopterygium incisum extract (NRE) rescues cognitive deficits in APP/PS1 Alzhneimer's disease mice by attenuating amyloid-beta, tau, and neuroinflammation pathology

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is a frequently occurring disease of the elderly, and "deficiency" is the root of AD. Most famous experts of traditional Chinese medicine believe that the disease is based on deficiency, and the deficiency of kidney essence is the basis. Notopterygium incisum (Qiang huo) is beneficial to bladder, liver, and kidneys. It is used to treat liver and kidney deficiency, language difficulties, and mental coma. Qiang huo yu feng tang has been used to treat liver and kidney deficiency, unclear language and mental paralysis in many traditional Chinese medicine books and records. In modern times, it has been used to treat AD and exhibited favourable efficacy.

AIM OF THE STUDY

This study attempts to investigate the effects of furocoumarins from Notopterygium incisum (NRE) on the Aβ cascade, tau pathology and inflammatory pathology of AD.

MATERIALS AND METHODS

In this study, we reported a detailed protocol for stabilizing HEK APPswe293T cells with lentivirus for the first time. This cell line can secrete high concentration of Aβ. In addition, we treated N2a cells with AKT/PKC specific inhibitors (wortmannin/GF-109203X) and established a tau pathological cell model (AKT/PKC N2a) by activating GSK3β and triggering hyperphosphorylation of tau. The Aβ levels and the expression of phosphorylated tau were detected by ELISA and Western blot. The cognitive ability of NRE on APP/PS1 mice was detected using a Morris water maze (MWM) assay and Aβ contents were also evaluated.

RESULTS

In HEK APPswe293T cells, NRE (10, 20, 40 μg/mL) significantly inhibited the secretion and production of Aβ in dose dependent manner. In addition, NRE also suppressed the expression of phosphorylated tau in wortmannin/GF-109203X treated N2a cells. Furthermore, NRE ameliorated the cognitive impairment of APP/PS1 mice, and the contents of Aβ, IL-1β and TNF-α were significantly depressed in hippocampus and cortex.

CONCLUSION

In conclusion, our results demonstrated that NRE has a potential anti-AD effect via the inhibition of the Aβ cascade, tau pathology and neuroinflammation in vitro and in vivo.

Discovery of Multitarget-Directed Ligands Against Influenza A Virus From Compound Yizhihao Through a Predictive System for Compound-Protein Interactions

Influenza A virus (IAV) is a threat to public health due to its high mutation rate and resistance to existing drugs. In this investigation, 15 targets selected from an influenza virus–host interaction network were successfully constructed as a multitarget virtual screening system for new drug discovery against IAV using Naïve Bayesian, recursive partitioning, and CDOCKER methods. The predictive accuracies of the models were evaluated using training sets and test sets. The system was then used to predict active constituents of Compound Yizhihao (CYZH), a Chinese medicinal compound used to treat influenza. Twenty-eight compounds with multitarget activities were selected for subsequent in vitro evaluation. Of the four compounds predicted to be active on neuraminidase (NA), chlorogenic acid, and orientin showed inhibitory activity in vitro. Linarin, sinensetin, cedar acid, isoliquiritigenin, sinigrin, luteolin, chlorogenic acid, orientin, epigoitrin, and rupestonic acid exhibited significant effects on TNF-α expression, which is almost consistent with predicted results. Results from a cytopathic effect (CPE) reduction assay revealed acacetin, indirubin, tryptanthrin, quercetin, luteolin, emodin, and apigenin had protective effects against wild-type strains of IAV. Quercetin, luteolin, and apigenin had good efficacy against resistant IAV strains in CPE reduction assays. Finally, with the aid of Gene Ontology biological process analysis, the potential mechanisms of CYZH action were revealed. In conclusion, a compound-protein interaction-prediction system was an efficient tool for the discovery of novel compounds against influenza, and the findings from CYZH provide important information for its usage and development.

LW-AFC, a new formula from the traditional Chinese medicine Liuwei Dihuang decoction, as a promising therapy for Alzheimer's disease: Pharmacological effects and mechanisms

LW-AFC is a new formula derived from the Liuwei Dihuang decoction, a classical traditional Chinese medicine prescription. Based on our research, LW-AFC is a promising drug for Alzheimer's disease (AD). The studies were conducted primarily in two typical AD mouse models: SAMP8 and APP/PS1 mice. The results showed that LW-AFC could improve many cognitive behaviors, such as spatial learning and memory ability, passive and active avoidance response, and object recognition memory capability. In addition, LW-AFC could also alleviate the AD-like pathology in animal models, such as neuron loss and Aβ deposition. Subsequent studies found that LW-AFC could rebalance hypothalamic-pituitary-adrenal (HPA) axis and hypothalamic-pituitary-gonadal (HPG) axis, and modulate the disturbance of immune system and gut flora. These data suggested that the anti-AD effects of LW-AFC might be mainly via modulating the neuroendocrine immunomodulation (NIM) network. As inhibiting the immune function by immunosuppressant could abolish the protective effects of LW-AFC against long-term potentiation (LTP) impairment model, it is likely that LW-AFC balancing the NIM network is initiated by modulating the immune system.

Active Fraction Combination from Liuwei Dihuang Decoction (LW-AFC) Alleviated the LPS-Induced Long-Term Potentiation Impairment and Glial Cells Activation in Hippocampus of Mice by Modulating Immune Responses

Neuroinflammation is known as a typical feature associated with many neurodegenerative diseases including Alzheimer's disease (AD) and impairs the synaptic plasticity of the hippocampus. LW-AFC is an active fraction combination being extracted from Liuwei Dihuang decoction, a classic traditional Chinese medicine prescription. This study aimed to investigate the effects of LW-AFC on synaptic plasticity in mice with lipopolysaccharide (LPS) treatment. The results showed that the administration of LPS caused fever and long-term potentiation (LTP) impairment in mice. The pretreatment with LW-AFC had an antipyretic effect on fever and improved the impaired LTP induced by LPS, alleviated the microglia and astrocytes activation in the hippocampus, regulated the abnormal T-lymphocyte subpopulation in the spleen and blood caused by LPS, and reduced the aberrant secretion of cytokines in the brain and plasma. The compounds paeoniflorin, morroniside, and loganic acid in LW-AFC regulated the TNF-α secretion in non-LPS- and LPS-stimulated BV-2 cells. These data suggest that LW-AFC improves the LPS-induced impairment of LTP and alleviates the activation of glial cells in the hippocampus, which might be associated with modulating immune responses.

Ozone Inhibits APP/Aβ Production and Improves Cognition in an APP/PS1 Transgenic Mouse Model

Alzheimer's disease (AD) is a progressive neurodegenerative disorder without effective treatment. Accumulating evidence demonstrates the production and deposition of amyloid-β peptides (Aβ) in the pathological mechanism of this disease. In our study, we investigated the effect of an ozone intraperitoneal injection on AD pathology in APP/PS1 transgenic mouse model. The male mice (5-months-old) received either ozone intraperitoneal injection (at 30 μg/ml or 50 μg/ml) or abdominocentesis administration daily for 25 days, and they were evaluated in the Morris water maze and the open field test for improvements in spatial learning-memory and working memory and anxious. Prefrontal cortex and hippocampus amyloid-β precursor protein (APP), along with other relevant biomarkers for AD, were measured through ELISA, western blot and immunohistochemistry. Results showed that ozone ameliorated the behavioral and pathological deterioration of APP/PS1 transgenic mice, and reduced the level of APP, which supports the therapeutic potential of administration of ozone in APP/PS1 mice.

Active fraction combination from Liuwei Dihuang decoction (LW-AFC) ameliorates corticosterone-induced long-term potentiation (LTP) impairment in mice in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Liuwei Dihuang decoction (LW), a classic formula in Traditional Chinese medicine (TCM), has been used for nearly one thousand years for various diseases with characteristic features of kidney yin deficiency. LW consists of 6 herbs including Dihuang (prepared root of Rehmannia glutinosa (Gaertn.) DC.), Shanyao (rhizome of Dioscorea polystachya Turcz.), Shanzhuyu (fruit of Cornus officinalis Siebold & Zucc.), Mudanpi (root bark of Paeonia × suffruticosa Andrews), Zexie (rhizome of Alisma plantago-aquatica L.) and Fuling (scleorotia of Wolfiporia extensa (Peck) Ginns). LW-active fraction combination (LW-AFC) is extracted from LW, it is effective for the treatment of kidney yin deficiency in many animal models. Recent researches indicate that the "kidney deficiency" is related to a disturbance in the neuroendocrine immunomodulation (NIM) network, and glucocorticoids play an important role in kidney deficiency.

AIM OF THE STUDY

This study evaluated the effects of LW-AFC and the active fractions (polysaccharide, LWB-B; glycoside, LWD-b; oligosaccharide, CA-30) on corticosterone (Cort)-induced long-term potentiation (LTP) impairment in vivo.

MATERIALS AND METHODS

In this study, LTP was used to evaluate the synaptic plasticity. LW-AFC was orally administered for seven days. The active fractions were given by either chronic administration (i.g., i.p., 7 days) or single administration (i.c.v., i.g., i.p.). Cort was injected subcutaneously 1 h before the high-frequency stimulation (HFS) to induce LTP impairment. Moreover, in order to research on the possible effective pathways, an antibiotic cocktail and an immunosuppressant were also used.

RESULTS

Chronic administration (i.g.) of LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Single administration (i.c.v., i.g., i.p.) of any of the active fractions had no effect on Cort-induced LTP impairment, while chronic administration (i.g., i.p.) of LWB-B or LWD-b showed positive effects against Cort. Interestingly, CA-30 only showed protective effects via i.g. administration, and there was little effect when CA-30 was administered i.p. In addition, when the intestinal microbiota was disrupted by application of the antibiotic cocktail, CA-30 showed little protective effects against Cort. The effects of LW-AFC were also abolished when the immune function was inhibited. In the hippocampal tissue, Cort treatment increased corticosterone and glutamate, and LW-AFC could inhibit the Cort-induced elevation of corticosterone and glutamate; there was little change in D-serine in Cort-treated animals, but LW-AFC could increase the D-serine levels.

CONCLUSION

LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Their protective effects are unlikely by a direct way, and immune modulation might be the common pathway. CA-30 could protect LTP from impairment via modulating the intestinal microbiota. Decreasing corticosterone and glutamate and increasing D-serine in the Cort-treated animals' hippocampal tissue might be one of the mechanisms for the neural protective effects of LW-AFC. Further study is needed to understand the underlying mechanisms.

A combination of indomethacin and atorvastatin ameliorates cognitive and pathological deterioration in PrP-hAβPPswe/PS1ΔE9 transgenic mice

Mounting evidence has shown that inflammation might drive Alzheimer's disease (AD) pathology and contribute to its exacerbation. Previous studies have indicated that indomethacin or atorvastatin are beneficial in treating AD; however, no significant clinical effects have been shown. Furthermore, no study has investigated the efficacy of combining these agents for treating AD. This study sought to determine the effect of a combination of indomethacin and atorvastatin in the PrP-hAβPPswe/PS1^ΔE9 (APP/PS1) transgenic AD mouse model. Treatment with indomethacin and atorvastatin ameliorated impairments in spatial learning and memory, and the active avoidance response in APP/PS1 mice. Moreover, we found a suppression of Aβ plaques and decreased concentration of Aβ_1-42 in the hippocampus of APP/PS1 mice following treatment. In addition, indomethacin and atorvastatin ameliorated abnormal cytokine secretion, lymphocyte subset disorder, and hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axis imbalances in APP/PS1 mice. The combination of indomethacin and atorvastatin restored immune and neuroendocrine processes, attenuated pathologic changes and cognitive impairments in APP/PS1 transgenic mice, and could thus be a potential therapeutic agent for AD.

Canine Cognitive Dysfunction: Pathophysiology, Diagnosis, and Treatment

Canine cognitive dysfunction (CCD) is the canine analog of human Alzheimer disease (AD). The pathophysiology of CCD/AD is multifaceted. CCD is common in aged (>8 years) dogs, affecting between 14% and 35% of the pet dog population. Apparent confusion, anxiety, disturbance of the sleep/wake cycle, and decreased interaction with owners are all common clinical signs of CCD. Although there is no cure for CCD, several proven effective therapeutic approaches are available for improving cognitive ability and maintaining a good quality of life; instituting such therapies early in the disease course is likely to have the greatest positive clinical effect.

Sodium rutin ameliorates Alzheimer's disease-like pathology by enhancing microglial amyloid-β clearance

The accumulation of aggregated amyloid-β (Aβ) in the brain is the first critical step in the pathogenesis of Alzheimer's disease (AD), which also includes synaptic impairment, neuroinflammation, neuronal loss, and eventual cognitive defects. Emerging evidence suggests that impairment of Aβ phagocytosis and clearance is a common phenotype in late-onset AD. Rutin (quercetin-3-rutinoside) has long been investigated as a natural flavonoid with different biological functions in some pathological circumstances. Sodium rutin (NaR), could promote Aβ clearance by increasing microglial by increasing the expression levels of phagocytosis-related receptors in microglia. Moreover, NaR promotes a metabolic switch from anaerobic glycolysis to mitochondrial OXPHOS (oxidative phosphorylation), which could provide microglia with sufficient energy (ATP) for Aβ clearance. Thus, NaR administration could attenuate neuroinflammation and enhance mitochondrial OXPHOS and microglia-mediated Aβ clearance, ameliorating synaptic plasticity impairment and eventually reversing spatial learning and memory deficits. Our findings suggest that NaR is a potential therapeutic agent for AD.

Amelioration of Alzheimer's disease pathology and cognitive deficits by immunomodulatory agents in animal models of Alzheimer's disease

The most common age-related neurodegenerative disease is Alzheimer’s disease (AD) characterized by aggregated amyloid-β (Aβ) peptides in extracellular plaques and aggregated hyperphosphorylated tau protein in intraneuronal neurofibrillary tangles, together with loss of cholinergic neurons, synaptic alterations, and chronic inflammation within the brain. These lead to progressive impairment of cognitive function. There is evidence of innate immune activation in AD with microgliosis. Classically-activated microglia (M1 state) secrete inflammatory and neurotoxic mediators, and peripheral immune cells are recruited to inflammation sites in the brain. The few drugs approved by the US FDA for the treatment of AD improve symptoms but do not change the course of disease progression and may cause some undesirable effects. Translation of active and passive immunotherapy targeting Aβ in AD animal model trials had limited success in clinical trials. Treatment with immunomodulatory/anti-inflammatory agents early in the disease process, while not preventive, is able to inhibit the inflammatory consequences of both Aβ and tau aggregation. The studies described in this review have identified several agents with immunomodulatory properties that alleviated AD pathology and cognitive impairment in animal models of AD. The majority of the animal studies reviewed had used transgenic models of early-onset AD. More effort needs to be given to creat models of late-onset AD. The effects of a combinational therapy involving two or more of the tested pharmaceutical agents, or one of these agents given in conjunction with one of the cell-based therapies, in an aged animal model of AD would warrant investigation.

Colivelin Ameliorates Impairments in Cognitive Behaviors and Synaptic Plasticity in APP/PS1 Transgenic Mice

Alzheimer's disease (AD) is the most common cause of dementia, and effective therapeutics are lacking. Colivelin (CLN), a novel, strong humanin derivative, is effective in vitro in preventing cell death induced by AD-causative genes and amyloid-β protein (Aβ) even at a low concentration. We recently demonstrated that intrahippocampal injection of CLN prevents Aβ25-35-induced deficits in spatial memory and synaptic plasticity in normal rats. Here, we further observed the effects of chronically intranasally (i.n.) administered CLN on cognitive behaviors and pathological hallmarks in 9-month-old APPswe/PS1dE9 (APP/PS1) AD mice using multiple behavioral tests and immunochemistry. The electrophysiological mechanism of CLN neuroprotection was also investigated by recording in vivo hippocampal long-term potentiation (LTP). CLN pretreatment effectively prevented impairments in new object recognition, working memory, and long-term spatial memory and reversed the depression of in vivo hippocampal LTP in APP/PS1 mice. Additionally, chronic application of CLN obviously reduced Aβ deposition in the hippocampus in APP/PS1 mice. These results indicate that CLN has strong neuroprotective effects on learning and memory behaviors in APP/PS1 mice and that this behavioral improvement is closely associated with the reduction of Aβ deposition and alleviation of LTP suppression in the hippocampus, supporting the potential of CLN for the prevention and treatment of AD.

The Effects of LW-AFC on the Hippocampal Transcriptome in Senescence-Accelerated Mouse Prone 8 Strain, a Mouse Model of Alzheimer's Disease

The senescence-accelerated mouse prone 8 (SAMP8) strain is considered a robust experimental model for developing preventative and therapeutic treatments for Alzheimer's disease (AD), a neurodegenerative disease which cannot be effectively prevented, halted, or cured. Our previous studies showed that LW-AFC, a new formula derived from the classical traditional Chinese medicinal prescription Liuwei Dihuang decoction, ameliorates cognitive deterioration in PrP-hAβPPswe/PS1ΔE9 transgenic mice and SAMP8 mice. This study aims to investigate the mechanism that mediates how LW-AFC improves cognitive deficit on the basis of the transcriptome. We conducted a genome-wide survey of gene expression in the hippocampus in mice from the senescence accelerated mouse resistant 1 (SAMR1) strain, from SAMP8 and from LW-AFC treated SAMP8. The results showed that LW-AFC reversed the transcriptome in the hippocampus of SAMP8 mice. The specific investigation of altered gene expression in subtypes defined by cognitive profiles indicated that the systemic lupus erythematosus pathway, spliceosomes, amyotrophic lateral sclerosis, and the insulin signaling were involved in the improvement of cognitive ability by LW-AFC. The expression of genes Enpp2, Etnk1, Epdr1, and Gm5900 in the hippocampus were correlated with that of LW-AFC's ameliorating cognitive impairment in SAMP8 mice. Because LW-AFC is composed of polysaccharides, glycosides, and oligosaccharides, we infer that LW-AFC has direct or indirect effects on altering gene expressions and regulating pathways in the hippocampus of SAMP8 mice. These data are helpful for the enhanced identification of LW-AFC as new therapeutic modalities to AD.