D-peptide-magnetic nanoparticles fragment tau fibrils and rescue behavioral deficits in a mouse model of Alzheimer's disease.

Amyloid fibrils of tau are increasingly accepted as a cause of neuronal death and brain atrophy in Alzheimer's disease (AD). Diminishing tau aggregation is a promising strategy in the search for efficacious AD therapeutics. Previously, our laboratory designed a six-residue, nonnatural amino acid inhibitor D-TLKIVW peptide (6-DP), which can prevent tau aggregation in vitro. However, it cannot block cell-to-cell transmission of tau aggregation. Here, we find D-TLKIVWC (7-DP), a d-cysteine extension of 6-DP, not only prevents tau aggregation but also fragments tau fibrils extracted from AD brains to neutralize their seeding ability and protect neuronal cells from tau-induced toxicity. To facilitate the transport of 7-DP across the blood-brain barrier, we conjugated it to magnetic nanoparticles (MNPs). The MNPs-DP complex retains the inhibition and fragmentation properties of 7-DP alone. Ten weeks of MNPs-DP treatment appear to reverse neurological deficits in the PS19 mouse model of AD. This work offers a direction for development of therapies to target tau fibrils.

A meritorious integrated medical regimen for hepatic fibrosis and its complications via the systematic review and meta-analysis for Dahuang Zhechong pill-based therapy.

Background: Hepatic fibrosis is a health challenge due to the absence of satisfactory therapy, especially at the cirrhosis stage. Dahuang Zhechong pill (DHZCP)-based therapy is reportedly a successful treatment for hepatic fibrosis and is even beneficial for the treatment of cirrhosis. Hence, a systematic review and clinical evidence assessment of DHZCP-based therapy should be performed, and clinical recommendations based on its efficacy for the treatment of hepatic fibrosis should be generated. With respect to potential indicators, the comparative value of the hepatic function, spleen thickness, and portal vein internal diameter should be evaluated. Materials and methods: PubMed, the Excerpta Medica Database, the Cochrane Library, the Web of Science, the WanFang Database, the Chinese Scientific Journal Database, and the Chinese National Knowledge Infrastructure database were searched to identify clinical trials. Three subgroup analyses were performed based on the stage of disease, medication use, and the course of treatment. Statistical analyses were performed using Review Manager 5.4. Results: A total of 18 studies including 1,494 patients were evaluated. The DHZCP-based therapy was effective in reducing the plasma levels of hyaluronic acid, and laminin, procollagen III, and IV collagen were also reduced irrespective of the hepatitis stage or the presence of hepatic cirrhosis. Abnormalities in alanine aminotransferase, aspartate aminotransferase, albumin, and total bilirubin were reversed. A 6-month course of treatment was the most beneficial DHZCP-based therapy regimen. Alanine aminotransferase improvement was more obvious in patients with cirrhosis, and alanine aminotransferase was reduced significantly in patients with hepatic cirrhosis. With respect to pharmacological mechanisms, DHZCP-based therapy could inhibit hepatic stellate cell growth and activation, reduce inflammation, and prevent extracellular matrix formation. Hepatic portal hypertension and splenomegaly were ameliorated significantly in the DHZCP-based therapy group. Conclusion: Dahuang Zhechong pill-based therapy has demonstrated efficacy as a treatment for hepatic fibrosis and cirrhosis. A 6-month course of treatment is the recommended option for DHZCP-based therapy in clinical practice. The combination of DHZCP-based therapy and entecavir is a favorable treatment for hepatic cirrhosis.

The effect of vitamin D supplementation on the progression of fibrosis in patients with chronic liver disease: A protocol for a systematic review and meta-analysis.

BACKGROUND: Hepatic fibrosis (HF) is the common pathological basis of chronic liver disease (CLD). Many data indicate that serum vitamin D (VD) levels in patients with liver fibrosis are significantly lower than those without liver fibrosis, and lower level of serum 1,25(OH)2D3 is also an independent risk factor for patients with liver fibrosis combined with other diseases. VD has the functions of anti-fibrosis, regulating cell proliferation and differentiation, anti-inflammatory, and immune regulation, Therefore, serum 1,25(OH)2D3 level may be negatively correlated with the progression of liver fibrosis. But there is absent convincing evidence-based medicine to confirm the efficacy of VD supplementation for CLD. Thus, we aimed to conduct this meta-analysis to summarize the efficacy of VD supplementation on the progression of fibrosis in patients with CLD. METHODS: The study only selects clinical randomized controlled trials of VD supplementation for CLD. We will search each database from the built-in until September 2020. The English literature mainly searches Cochrane Library, Pubmed, EMBASE, and Web of Science. While the Chinese literature comes from CNKI, CBM, VIP, and Wangfang database. Meanwhile, we will retrieve clinical trial registries and gray literature. Two researchers worked independently on literature selection, data extraction and quality assessment. The dichotomous data is represented by relative risk (RR), and the continuous is expressed by mean difference (MD) or standard mean difference (SMD), eventually the data is synthesized using a fixed effect model (FEM) or a random effect model (REM) depending on the heterogeneity. The serum VD level, hepatic function and serological indexes of hepatic fibrosis were evaluated as the main outcomes. While several secondary outcomes were also evaluated in this study. The statistical analysis of this Meta-analysis was conducted by RevMan software version 5.3. RESULTS: This meta-analysis will further determine the beneficial efficacy of VD supplementation on the progression of fibrosis in patients with CLD. CONCLUSION: This study determines the positive efficacy of VD supplementation for CLD. ETHICS AND DISSEMINATION: This review is based solely on a secondary study of published literatures and does not require ethics committee approval. Its conclusion will be disseminated in conference papers, magazines or peer-reviewed journals. REGISTRATION NUMBER: INPLASY202040054.

A Novel Model of Mixed Vascular Dementia Incorporating Hypertension in a Rat Model of Alzheimer's Disease.

Alzheimer's disease (AD) and mixed dementia (MxD) comprise the majority of dementia cases in the growing global aging population. MxD describes the coexistence of AD pathology with vascular pathology, including cerebral small vessel disease (SVD). Cardiovascular disease increases risk for AD and MxD, but mechanistic synergisms between the coexisting pathologies affecting dementia risk, progression and the ultimate clinical manifestations remain elusive. To explore the additive or synergistic interactions between AD and chronic hypertension, we developed a rat model of MxD, produced by breeding APPswe/PS1ΔE9 transgenes into the stroke-prone spontaneously hypertensive rat (SHRSP) background, resulting in the SHRSP/FAD model and three control groups (FAD, SHRSP and non-hypertensive WKY rats, n = 8-11, both sexes, 16-18 months of age). After behavioral testing, rats were euthanized, and tissue assessed for vascular, neuroinflammatory and AD pathology. Hypertension was preserved in the SHRSP/FAD cross. Results showed that SHRSP increased FAD-dependent neuroinflammation (microglia and astrocytes) and tau pathology, but plaque pathology changes were subtle, including fewer plaques with compact cores and slightly reduced plaque burden. Evidence for vascular pathology included a change in the distribution of astrocytic end-foot protein aquaporin-4, normally distributed in microvessels, but in SHRSP/FAD rats largely dissociated from vessels, appearing disorganized or redistributed into neuropil. Other evidence of SVD-like pathology included increased collagen IV staining in cerebral vessels and PECAM1 levels. We identified a plasma biomarker in SHRSP/FAD rats that was the only group to show increased Aqp-4 in plasma exosomes. Evidence of neuron damage in SHRSP/FAD rats included increased caspase-cleaved actin, loss of myelin and reduced calbindin staining in neurons. Further, there were mitochondrial deficits specific to SHRSP/FAD, notably the loss of complex II, accompanying FAD-dependent loss of mitochondrial complex I. Cognitive deficits exhibited by FAD rats were not exacerbated by the introduction of the SHRSP phenotype, nor was the hyperactivity phenotype associated with SHRSP altered by the FAD transgene. This novel rat model of MxD, encompassing an amyloidogenic transgene with a hypertensive phenotype, exhibits several features associated with human vascular or "mixed" dementia and may be a useful tool in delineating the pathophysiology of MxD and development of therapeutics.

Neuronal pentraxin 1: A synaptic-derived plasma biomarker in Alzheimer's disease.

Synaptic neurodegeneration is thought to be an early event initiated by soluble ß-amyloid (Aß) aggregates that closely correlates with cognitive decline in Alzheimer disease (AD). Apolipoprotein ε4 (APOE4) is the most common genetic risk factor for both familial AD (FAD) and sporadic AD; it accelerates Aß aggregation and selectively impairs glutamate receptor function and synaptic plasticity. However, its molecular mechanisms remain elusive and these synaptic deficits are difficult to monitor. AD- and APOE4-dependent plasma biomarkers have been proposed, but synapse-related plasma biomarkers are lacking. We evaluated neuronal pentraxin 1 (NP1), a potential CNS-derived plasma biomarker of excitatory synaptic pathology. NP1 is preferentially expressed in brain and involved in glutamate receptor internalization. NP1 is secreted presynaptically induced by Aß oligomers, and implicated in excitatory synaptic and mitochondrial deficits. Levels of NP1 and its fragments were increased in a correlated fashion in both brain and plasma of 7-8 month-old E4FAD mice relative to E3FAD mice. NP1 was also found in exosome preparations and reduced by dietary DHA supplementation. Plasma NP1 was higher in E4FAD+ (APOE4+/+/FAD+/-) relative to E4FAD- (non-carrier; APOE4+/+/FAD-/-) mice, suggesting NP1 is modulated by Aß expression. Finally, relative to normal elderly, plasma NP1 was also elevated in patients with mild cognitive impairment (MCI) and elevated further in the subset who progressed to early-stage AD. In those patients, there was a trend towards increased NP1 levels in APOE4 carriers relative to non-carriers. These findings indicate that NP1 may represent a potential synapse-derived plasma biomarker relevant to early alterations in excitatory synapses in MCI and early-stage AD.

Dietary DHA supplementation in an APP/PS1 transgenic rat model of AD reduces behavioral and Aß pathology and modulates Aß oligomerization.

Increased dietary consumption of docosahexaenoic acid (DHA) is associated with decreased risk for Alzheimer's disease (AD). These effects have been postulated to arise from DHA's pleiotropic effects on AD pathophysiology, including its effects on ß-amyloid (Aß) production, aggregation, and toxicity. While in vitro studies suggest that DHA may inhibit and reverse the formation of toxic Aß oligomers, it remains uncertain whether these mechanisms operate in vivo at the physiological concentrations of DHA attainable through dietary supplementation. We sought to clarify the effects of dietary DHA supplementation on Aß indices in a transgenic APP/PS1 rat model of AD. Animals maintained on a DHA-supplemented diet exhibited reductions in hippocampal Aß plaque density and modest improvements on behavioral testing relative to those maintained on a DHA-depleted diet. However, DHA supplementation also increased overall soluble Aß oligomer levels in the hippocampus. Further quantification of specific conformational populations of Aß oligomers indicated that DHA supplementation increased fibrillar (i.e. putatively less toxic) Aß oligomers and decreased prefibrillar (i.e. putatively more toxic) Aß oligomers. These results provide in vivo evidence suggesting that DHA can modulate Aß aggregation by stabilizing soluble fibrillar Aß oligomers and thus reduce the formation of both Aß plaques and prefibrillar Aß oligomers. However, since fibrillar Aß oligomers still retain inherent neurotoxicity, DHA may need to be combined with other interventions that can additionally reduce fibrillar Aß oligomer levels for more effective prevention of AD in clinical settings.

Clinical development of curcumin in neurodegenerative disease.

Curcumin, a polyphenolic antioxidant derived from the turmeric root has undergone extensive preclinical development, showing remarkable efficacy in wound repair, cancer and inflammatory disorders. This review addresses the rationale for its use in neurodegenerative disease, particularly Alzheimer's disease. Curcumin is a pleiotropic molecule, which not only directly binds to and limits aggregation of the ß-sheet conformations of amyloid characteristic of many neurodegenerative diseases but also restores homeostasis of the inflammatory system, boosts the heat shock system to enhance clearance of toxic aggregates, scavenges free radicals, chelates iron and induces anti-oxidant response elements. Although curcumin corrects dysregulation of multiple pathways, it may exert many effects via a few molecular targets. Pharmaceutical development of natural compounds like curcumin and synthetic derivatives have strong scientific rationale, but will require overcoming various hurdles including; high cost of trials, concern about profitability and misconceptions about drug specificity, stability, and bioavailability.

Loss of MAP function leads to hippocampal synapse loss and deficits in the Morris Water Maze with aging.

Hyperphosphorylation and accumulation of tau aggregates are prominent features in tauopathies, including Alzheimer's disease, but the impact of loss of tau function on synaptic and cognitive deficits remains poorly understood. We report that old (19-20 months; OKO) but not middle-aged (8-9 months; MKO) tau knock-out mice develop Morris Water Maze (MWM) deficits and loss of hippocampal acetylated α-tubulin and excitatory synaptic proteins. Mild motor deficits and reduction in tyrosine hydroxylase (TH) in the substantia nigra were present by middle age, but did not affect MWM performance, whereas OKO mice showed MWM deficits paralleling hippocampal deficits. Deletion of tau, a microtubule-associated protein (MAP), resulted in increased levels of MAP1A, MAP1B, and MAP2 in MKO, followed by loss of MAP2 and MAP1B in OKO. Hippocampal synaptic deficits in OKO mice were partially corrected with dietary supplementation with docosahexaenoic acid (DHA) and both MWM and synaptic deficits were fully corrected by combining DHA with α-lipoic acid (ALA), which also prevented TH loss. DHA or DHA/ALA restored phosphorylated and total GSK3ß and attenuated hyperactivation of the tau C-Jun N-terminal kinases (JNKs) while increasing MAP1B, dephosphorylated (active) MAP2, and acetylated α-tubulin, suggesting improved microtubule stability and maintenance of active compensatory MAPs. Our results implicate the loss of MAP function in age-associated hippocampal deficits and identify a safe dietary intervention, rescuing both MAP function and TH in OKO mice. Therefore, in addition to microtubule-stabilizing therapeutic drugs, preserving or restoring compensatory MAP function may be a useful new prevention strategy.

Curcumin suppresses soluble tau dimers and corrects molecular chaperone, synaptic, and behavioral deficits in aged human tau transgenic mice.

The mechanisms underlying Tau-related synaptic and cognitive deficits and the interrelationships between Tau species, their clearance pathways, and synaptic impairments remain poorly understood. To gain insight into these mechanisms, we examined these interrelationships in aged non-mutant genomic human Tau mice, with established Tau pathology and neuron loss. We also examined how these interrelationships changed with an intervention by feeding mice either a control diet or one containing the brain permeable beta-amyloid and Tau aggregate binding molecule curcumin. Transgene-dependent elevations in soluble and insoluble phospho-Tau monomer and soluble Tau dimers accompanied deficits in behavior, hippocampal excitatory synaptic markers, and molecular chaperones (heat shock proteins (HSPs)) involved in Tau degradation and microtubule stability. In human Tau mice but not control mice, HSP70, HSP70/HSP72, and HSP90 were reduced in membrane-enriched fractions but not in cytosolic fractions. The synaptic proteins PSD95 and NR2B were reduced in dendritic fields and redistributed into perikarya, corresponding to changes observed by immunoblot. Curcumin selectively suppressed levels of soluble Tau dimers, but not of insoluble and monomeric phospho-Tau, while correcting behavioral, synaptic, and HSP deficits. Treatment increased PSD95 co-immunoprecipitating with NR2B and, independent of transgene, increased HSPs implicated in Tau clearance. It elevated HSP90 and HSC70 without increasing HSP mRNAs; that is, without induction of the heat shock response. Instead curcumin differentially impacted HSP90 client kinases, reducing Fyn without reducing Akt. In summary, curcumin reduced soluble Tau and elevated HSPs involved in Tau clearance, showing that even after tangles have formed, Tau-dependent behavioral and synaptic deficits can be corrected.

Ganoderma lucidum Protects Dopaminergic Neuron Degeneration through Inhibition of Microglial Activation.

Abundant evidence has suggested that neuroinflammation participates in the pathogenesis of Parkinson's disease (PD). The emerging evidence has supported that microglia may play key roles in the progressive neurodegeneration in PD and might be a promising therapeutic target. Ganoderma lucidum (GL), a traditional Chinese medicinal herb, has been shown potential neuroprotective effects in our clinical trials that make us to speculate that it might possess potent anti-inflammatory and immunomodulating properties. To test this hypothesis, we investigated the potential neuroprotective effect of GL and possible underlying mechanism of action through protecting microglial activation using co-cultures of dopaminergic neurons and microglia. The microglia is activated by LPS and MPP(+)-treated MES 23.5 cell membranes. Meanwhile, GL extracts significantly prevent the production of microglia-derived proinflammatory and cytotoxic factors [nitric oxide, tumor necrosis factor-α (TNF-α), interlukin 1ß (IL-1ß)] in a dose-dependent manner and down-regulate the TNF-α and IL-1ß expressions on mRNA level as well. In conclusion, our results support that GL may be a promising agent for the treatment of PD through anti-inflammation.

Suprachiasmatic nucleus slices induce molecular oscillations in fibroblasts.

The mammalian circadian pacemaker has been localized to the hypothalamic suprachiasmatic nucleus (SCN), where a set of clock genes and their resulting proteins form interlocking transcriptional/translational feedback loops to sustain molecular and functional oscillations. Interestingly, peripheral tissues and stimulated fibroblasts have also displayed daily oscillations, which are thought to be synchronized by the SCN in vivo. However, intercellular communications between the SCN and other tissues or cells remain poorly understood. Therefore, a novel co-culture model was established in the present study to understand the interactions between central and peripheral oscillators in co-cultures of SCN slices and NIH/3T3 cells in a serum-free condition. Expression profiles of Per1 and Rev-Erb alpha were measured in NIH/3T3 cells using real-time PCR. Results demonstrated that diffusible signals released from SCN slices could regulate molecular rhythms in cultured fibroblasts. Moreover, Rev-Erb alpha oscillation was more robust and appeared earlier than Per1.

Inhibition of tyrosine hydroxylase expression in alpha-synuclein-transfected dopaminergic neuronal cells.

Although the aberrant expression of alpha-synuclein (alpha-Syn) is toxic to dopaminergic neurons, little is known about the correlation between the abnormality of alpha-Syn and the expression of tyrosine hydroxylase (TH), a rate-limiting enzyme for the synthesis of dopamine neurotransmitter. In this study, the MES23.5 rat dopaminergic cell line transfected with wild-type human alpha-Syn cDNA (h alpha-Syn) construct was used to investigate the association between alpha-Syn and TH. Immunocytochemical staining and Western blot for TH showed that the TH expression was greatly decreased in h alpha-Syn-transfected cells. Northern blot confirmed that the TH mRNA level was also dramatically reduced. Reduction of TH protein levels did not affect the growth and proliferation of the transfected cells. No apparent cell injury or death was observed. These results suggest that an abnormal expression of alpha-Syn may inhibit TH synthesis in dopaminergic cells.