Chemical profiling with HPLC-FTMS of exogenous and endogenous chemicals susceptible to the administration of chotosan in an animal model of type 2 diabetes-induced dementia

True or false? Alzheimer's disease is type 3 diabetes: Evidences from bench to bedside

Globally, Alzheimer's disease (AD) is the most widespread chronic neurodegenerative disorder, leading to cognitive impairment, such as aphasia and agnosia, as well as mental symptoms, like behavioral abnormalities, that place a heavy psychological and financial burden on the families of the afflicted. Unfortunately, no particular medications exist to treat AD, as the current treatments only impede its progression.The link between AD and type 2 diabetes (T2D) has been increasingly revealed by research; the danger of developing both AD and T2D rises exponentially with age, with T2D being especially prone to AD. This has propelled researchers to investigate the mechanism(s) underlying this connection. A critical review of the relationship between insulin resistance, Aβ, oxidative stress, mitochondrial hypothesis, abnormal phosphorylation of Tau protein, inflammatory response, high blood glucose levels, neurotransmitters and signaling pathways, vascular issues in AD and diabetes, and the similarities between the two diseases, is presented in this review. Grasping the essential mechanisms behind this detrimental interaction may offer chances to devise successful therapeutic strategies.

Quantitative imaging of natural products in fine brain regions using desorption electrospray ionization mass spectrometry imaging (DESI-MSI): Uncaria alkaloids as a case study

Uncaria species (Rubiaceae) are used as traditional Chinese medicines (TCMs) to treat central nervous system (CNS) diseases, and monoterpene indole alkaloids are the main bioactive constituents. Localization and quantification of CNS drugs in fine brain regions are important to provide insights into their pharmacodynamics, for which quantitative mass spectrometry imaging (MSI) has emerged as a powerful technique. A systematic study of the quantitative imaging of seven Uncaria alkaloids in rat brains using desorption electrospray ionization mass spectrometry imaging (DESI-MSI) was presented. The distribution of the alkaloids in thirteen brain regions was quantified successfully using the calibration curves generated by a modified on-tissue approach. The distribution trend of different Uncaria alkaloids in the rat brain was listed as monoterpene indole alkaloids > monoterpene oxindole alkaloids, R-configuration epimers > S-configuration epimers. Particularly, Uncaria alkaloids were detected directly in the pineal gland for the first time and their enrichment phenomenon in this region had an instructive significance in future pharmacodynamic studies.

Explore of the beneficial effects of Huang-Lian-Jie-Du Decoction on diabetic encephalopathy in db/db mice by UPLC-Q-Orbitrap HRMS/MS based untargeted metabolomics analysis

Diabetic encephalopathy (DE) is a severe diabetic complication with cognitive dysfunction. Huang-Lian-Jie-Du Decoction (HLJDD), a famous traditional Chinese formula, is effective for the treatment of diabetes mellitus and Alzheimer's disease in clinical practices, however, the therapeutic effects and the underlying mechanisms of HLJDD on DE is unclear yet. With this purpose, behavior test, brain histological and biochemical analysis were estimated to assess the beneficial effects of HLJDD on DE. Plasma samples were collected for metabolomics analysis based on UPLC-Q-Orbitrap HRMS/MS and chemometric analysis. As a result, morris water maze test revealed that HLJDD could effectively improve the learning and memory abilities in db/db mice. Brain histological and biochemical analysis indicated that HLJDD could protect against neurodegeneration and oxidative stress in db/db mice. Meanwhile, a total of 21 potential biomarkers with significant differences were identified between Model group and Control group using untargeted metabolomics strategy. Among them, 11 metabolites showed a trend towards the normal levels after HLJDD intervention. These metabolites principally involved in glycerophospholipid metabolism, fatty acid β-oxidation, linoleic acid metabolism, glucose metabolism and glutathione metabolism based on the metabolic pathway analysis, which were regulated in DE model mice after HLJDD intervention. Generally, the results demonstrated that HLJDD had beneficial effects on DE, which could be mediated via ameliorating the metabolic disorders.

Integrated 16S rRNA Sequencing, Metagenomics, and Metabolomics to Characterize Gut Microbial Composition, Function, and Fecal Metabolic Phenotype in Non-obese Type 2 Diabetic Goto-Kakizaki Rats

Type 2 diabetes mellitus (T2DM) is one of the most prevalent endocrine diseases in the world. Recent studies have shown that dysbiosis of the gut microbiota may be an important contributor to T2DM pathogenesis. However, the mechanisms underlying the roles of the gut microbiome and fecal metabolome in T2DM have not been characterized. Recently, the Goto-Kakizaki (GK) rat model of T2DM was developed to study the clinical symptoms and characteristics of human T2DM. To further characterize T2DM pathogenesis, we combined multi-omics techniques, including 16S rRNA gene sequencing, metagenomic sequencing, and metabolomics, to analyze gut microbial compositions and functions, and further characterize fecal metabolomic profiles in GK rats. Our results showed that gut microbial compositions were significantly altered in GK rats, as evidenced by reduced microbial diversity, altered microbial taxa distribution, and alterations in the interaction network of the gut microbiome. Functional analysis based on the cluster of orthologous groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations suggested that 5 functional COG categories belonged to the metabolism cluster and 33 KEGG pathways related to metabolic pathways were significantly enriched in GK rats. Metabolomics profiling identified 53 significantly differentially abundant metabolites in GK rats, including lipids and lipid-like molecules. These lipids were enriched in the glycerophospholipid metabolic pathway. Moreover, functional correlation analysis showed that some altered gut microbiota families, such as Verrucomicrobiaceae and Bacteroidaceae, significantly correlated with alterations in fecal metabolites. Collectively, the results suggested that an altered gut microbiota is associated with T2DM pathogenesis.

Comorbidity Analysis between Alzheimer's Disease and Type 2 Diabetes Mellitus (T2DM) Based on Shared Pathways and the Role of T2DM Drugs

Background:

Various studies suggest a comorbid association between Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) indicating that there could be shared underlying pathophysiological mechanisms.

Objective:

This study aims to systematically model relevant knowledge at the molecular level to find a mechanistic rationale explaining the existing comorbid association between AD and T2DM.

Method:

We have used a knowledge-based modeling approach to build two network models for AD and T2DM using Biological Expression Language (BEL), which is capable of capturing and representing causal and correlative relationships at both molecular and clinical levels from various knowledge resources.

Results:

Using comparative analysis, we have identified several putative “shared pathways”. We demonstrate, at a mechanistic level, how the insulin signaling pathway is related to other significant AD pathways such as the neurotrophin signaling pathway, PI3K/AKT signaling, MTOR signaling, and MAPK signaling and how these pathways do cross-talk with each other both in AD and T2DM. In addition, we present a mechanistic hypothesis that explains both favorable and adverse effects of the anti-diabetic drug metformin in AD.

Conclusion:

The two computable models introduced here provide a powerful framework to identify plausible mechanistic links shared between AD and T2DM and thereby identify targeted pathways for new therapeutics. Our approach can also be used to provide mechanistic answers to the question of why some T2DM treatments seem to increase the risk of AD.

Effective Separation and Simultaneous Determination of Corynoxeine and Its Metabolites in Rats by High-Performance Liquid Chromatography with Tandem Mass Spectrometry and Application to Pharmacokinetics and In Vivo Distribution in Main Organs

An effective separation and simultaneous determination of corynoxeine and its metabolites using high-performance liquid chromatography with tandem mass spectrometry was developed and validated. The method was applied to pharmacokinetics and in vivo distribution investigations in rats after oral (0.105 mmol kg(-1)) and intravenous (0.0105 mmol kg(-1)) doses of corynoxeine. Its brain uptake index was of 3.08 × 10(-11) mol g(-1) at 3 h and 3.75 × 10(-11) mol g(-1) at 74 min after oral and intravenous doses, respectively.

Experimental Models to Study the Neuroprotection of Acidic Postconditioning Against Cerebral Ischemia

Stroke is one of the leading causes of mortality and disability worldwide, with limited therapeutic approaches. As an endogenous strategy for neuroprotection, postconditioning treatments have proven to be promising therapies against cerebral ischemia. However, complicated procedures and potential safety issues limit their clinical application. To overcome these disadvantages, we have developed acidic postconditioning (APC) as a therapy for experimental focal cerebral ischemia. APC refers to the mild acidosis treatment by inhaling CO2 during reperfusion following ischemia. Here we present two models to execute APC in vitro and in vivo, respectively. The oxygen-glucose deprivation (OGD) treatment of mice and the corticostriatal occlusion and middle cerebral artery occlusion (MCAO) of mice were employed to mimic cerebral ischemia. APC can be simply achieved by transferring brain slices to acidic buffer bubbled with 20% CO2, or by mice inhaling 20% CO2. APC showed significant protective effects against cerebral ischemia, as reflected by tissue viability and brain infarct volume.

A Systematic Strategy for Discovering a Therapeutic Drug for Alzheimer's Disease and Its Target Molecule

Natural medicines are attractive sources of leading compounds that can be used as interventions for neurodegenerative disorders. The complexity of their chemical components and undetermined bio-metabolism have greatly hindered both the use of natural medicines and the identification of their active constituents. Here, we report a systematic strategy for evaluating the bioactive candidates in natural medicines used for Alzheimer's disease (AD). We found that Drynaria Rhizome could enhance memory function and ameliorate AD pathologies in 5XFAD mice. Biochemical analysis led to the identification of the bio-effective metabolites that are transferred to the brain, namely, naringenin and its glucuronides. To explore the mechanism of action, we combined the drug affinity responsive target stability with immunoprecipitation-liquid chromatography/mass spectrometry analysis, identifying the collapsin response mediator protein 2 protein as a target of naringenin. Our study indicates that biochemical analysis coupled with pharmacological methods can be used in the search for new targets for AD intervention.

Chemical and biological comparison of different sections of Uncaria rhynchophylla (Gou-Teng)

Uncaria rhynchophylla (Gou-Teng in Chinese) is officially documented in Chinese pharmacopoeia as one of the authentic sources for the crude drug of Gou-Teng which has long been used for mental and cardiovascular diseases. Indole alkaloids are the characteristic constituents responsible for the desired hypotensive effect; however, the psychiatric active constituents of Gou-Teng are still unclear. According to traditional Chinese medicine theory, only the hook-bearing stems of U. rhynchophylla are used as the crude materials for Gou-Teng, while its leaves and fruits are scarcely used. The present study aimed to compare the metabolic fingerprints of different parts (hooks, stems, leaves and fruits) of U. rhynchophylla by LC-DAD-MS/MS analysis and further evaluate their psychiatric activities on HEK293 cell line in vitro. A total of 38 constituents including 26 alkaloids, six flavonoids, two triterpenoids, two chlorogenic acid analogs and two other compounds were characterized. The different parts of U. rhynchophylla can be well differentiated from their chemical profiles. Leaves displayed the most potent activity on both MT₁ and MT₂ receptors, with agonistic rates of 39.7% and 97.6%. For 5-HT_1A and 5-HT_2C receptors, hooks showed the strongest activity with agonistic rates of 92.6% and 83.1%, respectively. This investigation provided valuable information for understanding the chemical divergence between different parts of U. rhynchophylla, and their substantial bases for psychiatric purposes.

Chotosan improves Aβ1-42-induced cognitive impairment and neuroinflammatory and apoptotic responses through the inhibition of TLR-4/NF-κB signaling in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Recently, the focus on neuroinflammation is intensified as its complex pathophysiological role has emerged in multiple central nervous system(CNS) disorders. Chotosan (CTS), known as a traditional herbal formula, is often utilized to treat relevant nervous system diseases in China. It was demonstrated effectively to alleviate cognitive deficit associated with aging, diabetes, hypoperfusion and cerebral ischemia. However, the effects of CTS on Aβ1-42-induced cognitive dysfunction remain unclear. Here, we further investigated the effects of chotosan on memory performance, neuroinflammation and apoptotic responses.

MATERIALS AND METHODS

The learning and memory ability is evaluated by Morris water maze (MWM) task and Y-maze test following intrahippocampal infusion of aggregated Aβ1-42. The expression level of toll-like receptor 4 (TLR-4), NF-κB p65, Bcl-2 and Bax was examined by Western blot. TLR-4 level is also assessed by immunohistochemistry (IHC). Enzyme-linked immunosorbent assay (ELISA) was conducted to determine the generation of inflammatory mediators. The caspase-3 activity is analyzed by commercial kits.

RESULTS

The repeated treatment with CTS (750mg/kg or 375mg/kg per day) for 3 weeks significantly restored Aβ1-42-induced memory impairment in mice. Meanwhile, this treatment also remarkably reduced TLR-4 and NF-κB p65 expression accompanying with the diminished release of proinflammatory cytokines including TNF-α and IL-1β in hippocampus. The neuronal apoptosis is also inhibited as evidenced by increase in Bcl-2/Bax ratio and decrease in pro-apoptotic protein caspase-3 activity compared to that of the model mice.

CONCLUSIONS

Our results show for the first time that chotosan can ameliorate Aβ1-2-induced memory dysfunction via inhibiting neuroinflammation and apoptosis at least partially mediated by TLR-4/NF-κB signaling pathway.

Protective effects of a Chotosan Fraction and its active components on β-amyloid-induced neurotoxicity

Chotosan (CTS) is a traditional Kampo prescription used to treat chronic headache and hypertension. Recent clinical studies demonstrated that CTS has ameliorative effects on dementia. This study aims to identify the anti-Alzheimer components in CTS. β-amyloid (Aβ) is considered to play a central role in the pathophysiology of Alzheimer's disease. CTS-E, a fraction of CTS, showed significant protective effects on Aβ-induced neurotoxicity. High-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used for the qualitative analysis of it. Among the identified constituents, neuroprotective effects against Aβ(25-35)-induced neurotoxicity of 10 major compounds were tested by MTT assay. Their inhibitory action on Aβ(1-42) self-induced aggregation was measured by Thioflavin T-binding assay. The results showed that caffeic acid, chlorogenic acid, 1,5-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid had significant neuroprotective effects on Aβ(25-35)-induced neurotoxicity. Besides these phenolic acids, nobiletin and hesperidin could also inhibit Aβ(1-42) self-induced aggregation. In conclusion, the neuroprotective fraction, CTS-E, could protect PC12 cells from Aβ-induced neurotoxicity. Anti-oxidative effects may at least partly mediate the neuroprotective effects of it. Phenolic acids from Chrysanthemi Flos and flavonoids from Citri Reticulatae Pericarpium might be the effective constituents in CTS-E.

Analysis of chemical properties of edible and medicinal ginger by metabolomics approach

In traditional herbal medicine, comprehensive understanding of bioactive constituent is important in order to analyze its true medicinal function. We investigated the chemical properties of medicinal and edible ginger cultivars using a liquid-chromatography mass spectrometry (LC-MS) approach. Our PCA results indicate the importance of acetylated derivatives of gingerol, not gingerol or shogaol, as the medicinal indicator. A newly developed ginger cultivar, Z. officinale cv. Ogawa Umare or "Ogawa Umare" (OG), contains more active ingredients, showing properties as a new resource for the production of herbal medicines derived from ginger in terms of its chemical constituents and rhizome yield.