A novel Zebrafish model of Alzheimer's disease by Aluminium chloride; involving nitro-oxidative stress, neuroinflammation and cholinergic pathway

Identification of a novel pyrrolo[2,3-b]pyridine compound as a potent glycogen synthase kinase 3β inhibitor for treating Alzheimer's disease

Herein, a novel pyrrolo[2,3-b]pyridine-based glycogen synthase kinase 3β (GSK-3β) inhibitor, S01, was rationally designed and synthesised to target Alzheimer's disease (AD). S01 inhibited GSK-3β, with an IC50 of 0.35 ± 0.06 nM, and had an acceptable kinase selectivity for 24 structurally similar kinases. Western blotting assays indicated that S01 efficiently increased the expression of p-GSK-3β-Ser9 and decreased p-tau-Ser396 levels in a dose-dependent manner. In vitro cell experiments, S01 showed low cytotoxicity to SH-SY5Y cells, significantly upregulated the expression of β-catenin and neurogenesis-related biomarkers, and effectively promoted the outgrowth of differentiated neuronal neurites. Moreover, S01 substantially ameliorated dyskinesia in AlCl3-induced zebrafish AD models at a concentration of 0.12 μM, which was more potent than Donepezil (8 μM) under identical conditions. Acute toxicity experiments further confirmed the safety of S01 in vivo. Our findings suggested that S01 is a prospective GSK-3β inhibitor and can be tested as a candidate for treating AD.

Using Single-Cell RNA sequencing with Drosophila, Zebrafish, and mouse models for studying Alzheimer's and Parkinson's disease

Alzheimer's and Parkinson's disease are the most common neurodegenerative diseases, significantly affecting the elderly with no current cure available. With the rapidly aging global population, advancing research on these diseases becomes increasingly critical. Both disorders are often studied using model organisms, which enable researchers to investigate disease phenotypes and their underlying molecular mechanisms. In this review, we critically discuss the strengths and limitations of using Drosophila, zebrafish, and mice as models for Alzheimer's and Parkinson's research. A focus is the application of single-cell RNA sequencing, which has revolutionized the field by providing novel insights into the cellular and transcriptomic landscapes characterizing these diseases. We assess how combining animal disease modeling with high-throughput sequencing and computational approaches has advanced the field of Alzheimer's and Parkinson's disease research. Thereby, we highlight the importance of integrative multidisciplinary approaches to further our understanding of disease mechanisms and thus accelerating the development of successful therapeutic interventions.

Neuroprotective Effects of Berberine Chloride Against the Aluminium Chloride-Induced Alzheimer's Disease in Zebra Fish Larvae

Alzheimer's disease (AD) is a neurodegenerative disease distinguished by cognitive and memory deficits. A lack of memory, cognition, and other forms of cognitive dissonance characterizes AD, which affects approximately 50 million people worldwide. This study aimed to identify the neuroprotective effects of berberine chloride (BC) against aluminium chloride (AlCl3)-induced AD in zebrafish larvae by inhibiting oxidative stress and neuroinflammation. BC toxicity was assessed by evaluating survival rates, malformations, and heart rates in zebrafish larvae following treatment with varying concentrations of BC. This study elucidates the mechanisms of BC through an extensive range of biochemical assays, behavioral testing, and molecular docking analysis. The developmental toxicity assessment of BC indicated that doses up to 40 μM did not cause any developmental abnormalities until 96 h post fertilization. The LC50 value of BC in zebrafish larvae was found to be 50.16 μM. The biochemical and behavioral changes induced by AlCl3 in zebrafish larvae were significantly mitigated by BC treatment. Our findings demonstrate that BC can reduce total cholesterol and triglyceride levels in AlCl3-induced AD zebrafish larvae. Our molecular docking results indicated that BC significantly interacted with the ABCA1 protein, suggesting that BC may act as an ABCA1 agonist. Based on our results, it can be concluded that BC may serve as an effective therapeutic agent for mitigating oxidative stress by altering cholesterol metabolism in AlCl3-induced AD.

Redox Homeostasis, Gut Microbiota, and Epigenetics in Neurodegenerative Diseases: A Systematic Review

Neurodegenerative diseases encompass a spectrum of disorders marked by the progressive degeneration of the structure and function of the nervous system. These conditions, including Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS), and Multiple sclerosis (MS), often lead to severe cognitive and motor deficits. A critical component of neurodegenerative disease pathologies is the imbalance between pro-oxidant and antioxidant mechanisms, culminating in oxidative stress. The brain's high oxygen consumption and lipid-rich environment make it particularly vulnerable to oxidative damage. Pro-oxidants such as reactive nitrogen species (RNS) and reactive oxygen species (ROS) are continuously generated during normal metabolism, counteracted by enzymatic and non-enzymatic antioxidant defenses. In neurodegenerative diseases, this balance is disrupted, leading to neuronal damage. This systematic review explores the roles of oxidative stress, gut microbiota, and epigenetic modifications in neurodegenerative diseases, aiming to elucidate the interplay between these factors and identify potential therapeutic strategies. We conducted a comprehensive search of articles published in 2024 across major databases, focusing on studies examining the relationships between redox homeostasis, gut microbiota, and epigenetic changes in neurodegeneration. A total of 161 studies were included, comprising clinical trials, observational studies, and experimental research. Our findings reveal that oxidative stress plays a central role in the pathogenesis of neurodegenerative diseases, with gut microbiota composition and epigenetic modifications significantly influencing redox balance. Specific bacterial taxa and epigenetic markers were identified as potential modulators of oxidative stress, suggesting novel avenues for therapeutic intervention. Moreover, recent evidence from human and animal studies supports the emerging concept of targeting redox homeostasis through microbiota and epigenetic therapies. Future research should focus on validating these targets in clinical settings and exploring the potential for personalized medicine strategies based on individual microbiota and epigenetic profiles.

Neuroprotective effects of Shenghui decoction via inhibition of the JNK/p38 MAPK signaling pathway in an AlCl3-induced zebrafish (Danio rerio) model of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is a multi-factorial degenerative disease, and multi-targeted therapies targeting multiple pathogenic mechanisms should be explored. Shenghui decoction (SHD) is an ancient traditional Chinese medicine (TCM) formula used clinically to alleviate AD. However, the precise mechanism of action of SHD as a therapeutic agent for AD remains unclear.

AIM OF THE STUDY

This study investigated the neuroprotective properties and potential mechanisms of action of SHD in mitigating AD-like symptoms induced by AlCl3 in a zebrafish model.

MATERIALS AND METHODS

Active components of SHD were detected using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Zebrafish were exposed to AlCl3 (200 μg/L) for 30 days to establish an AD zebrafish model. AlCl3-exposed zebrafish were treated with SHD or donepezil. Behavioral tests were used to assess learning and memory, locomotor activity, and AD-related anxiety and aggression in AlCl3-exposed zebrafish. Nissl staining and transmission electron microscopy were used to evaluate histological alterations in brain neurons. The concentrations of pro-inflammatory cytokines (tumor necrosis factor-α, TNF-α; interleukin-1β, IL-1β) were quantified using Enzyme-linked immunosorbent assay (ELISA). Markers of oxidative stress and cholinergic activity (acetylcholinesterase, AChE) were detected using biochemical assays. Western blotting and immunofluorescence were used to detect the protein expression levels of Aβ, p-tau, PSD-95, synaptophysin, TLR4, phosphorylation of NF-κB p65, p38, and JNK.

RESULTS

Fifteen SHD compounds were identified by UPLC-MS/MS analysis. SHD improved AlCl3-induced dyskinesia, learning and memory impairment, anxiety-like behavior, and aggressive behavior in zebrafish. AlCl3-exposed zebrafish showed AD-like pathology, overexpression of Aβ, hyperphosphorylated tau protein, marked neuronal damage, decreased expression of synaptic proteins, synaptophysin, and PSD-95, and impairment of synaptic structural plasticity. These effects were reversed by the SHD treatment. We also observed that SHD ameliorated oxidative stress and decreased AChE activity and inflammatory cytokine levels. These effects are similar to those observed for donepezil. Meanwhile, SHD could decrease the protein expression of TLR4 and inhibit phosphorylation of NF-κB, JNK, and p38 MAPK. These results demonstrate that SHD has the potential to exert neuroprotective effects, which may be partly mediated via inhibition of the JNK/p38 MAPK signaling pathway.

CONCLUSIONS

Our findings revealed the therapeutic mechanism of SHD in mitigating AD progression and suggested that SHD is a potent neuroprotectant that contributes to the future development of TCM modernization and broader clinical applications.