AdipoRon promotes amyloid-β clearance through enhancing autophagy via nuclear GAPDH-induced sirtuin 1 activation in Alzheimer's disease

Berbamine targets the FKBP12-rapamycin-binding (FRB) domain of the mTOR complex to promote microglial autophagy and ameliorate neuroinflammation in Alzheimer's disease

BACKGROUND

Berbamine (BBM), a natural bisbenzylisoquinoline alkaloid, has demonstrated promising effects in ameliorating pathological process and inflammation response in central neuronal system (CNS). Alzheimer's disease (AD), primarily characterized by amyloid-beta (Aβ)-containing extra-cellular plaques and abnormal "autophagy-brake regulation" of neuroinflammation, currently lacks of effective therapeutic options. Therapeutics of BBM on AD is indeed intriguing, and the potential targets and mechanisms are vague yet.

PURPOSE

This study is designed to elucidate the therapeutic potential of BBM on AD, focusing particularly on its ability to enhance autophagy, induce microglial M2 polarization, and to uncover the underlying molecular mechanisms and implicated targets.

METHODS

The therapeutic efficacy of BBM was systematically investigated in APP/PS1 mice, with a focus on its potential to enhance autophagy, induce M2 polarization in microglia, and facilitate the clearance of Aβ plaques. Cognitive function was rigorously assessed through a series of behavioral tests, including the Morris Water Maze and Object Location Task. Immunofluorescence was employed to visualize the spatial distribution of inflammatory cytokines and autophagic markers within the brain parenchyma. Quantitative measurements of these cytokines were obtained using enzyme-linked immunosorbent assay (ELISA). Western blotting was utilized to analyze protein profiles associated with autophagy and microglial phenotypes. Additionally, chemo-proteomics and molecular docking techniques were applied to identify the key molecular targets of BBM.

RESULTS

BBM treatment significantly ameliorated cognitive dysfunction and reduced Aβ plaque deposition in APP/PS1 transgenic mice. Notably, BBM promoted microglial polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, accompanied by attenuation of neuroinflammation. Mechanistically, BBM exerted its effects through inhibition of mTOR signaling via direct interaction with the FKBP12-rapamycin-binding domain, thereby restoring autophagic flux and facilitating M2 microglial polarization. The mTOR activator MHY1485 abrogated the beneficial effects of BBM, highlighting the pivotal role of mTOR inhibition in its mechanism of action.

CONCLUSIONS

BBM promotes M2 microglial polarization and restores autophagic flux in AD by inhibiting mTOR signaling, representing a novel dual-modulatory mechanism for AD intervention. These findings highlight BBM's ability to target mTOR and intersecting pathways, offering a promising disease-modifying therapeutic approach for AD and other neurodegenerative disorders.

Pharmacological Blocking of Adiponectin Receptors Induces Alzheimer's Disease-like Neuropathology and Impairs Hippocampal Function

Background/Objectives: Previous studies have shown that adiponectin deficiency or blocking adiponectin receptors (AdipoRs) in the brain can lead to an Alzheimer's disease (AD)-like neuropathology. While AdipoRs are abundantly expressed in peripheral tissues, the effects of blocking these receptors in the peripheral tissues on the brain are unclear. This study investigates the impacts of blocking AdipoRs with a peripheral administration of ADP400, an antagonist peptide that targets AdipoRs on cognitive performance, hippocampal adult neurogenesis, and AD-like neuropathology in mice. Methods: Adult mice were intraperitoneally administered with ADP400 peptide that blocks peripheral AdipoRs continuously for 21 days, followed by a battery of behavioral test for mood and memory performance. Results: ADP400-treated mice exhibited impaired memory performance and increased anxiety-like behaviors. Molecular analyses revealed heightened hyperphosphorylation of tau and increased β-amyloid levels, alongside decreased expression of AdipoRs and PP2A in the hippocampus, suggesting a critical role of AdipoRs in AD-like neuropathology. Furthermore, ADP400 treatment significantly reduced hippocampal adult neurogenesis, as indicated by decreased BrdU, Ki67, and DCX staining. Inhibiting peripheral adiponectin receptors could lead to tau hyperphosphorylation and accumulated β-amyloid levels. Conclusions: These findings highlight the critical role of peripheral manipulation of adiponectin receptors in modulating cognitive function and adult neurogenesis, offering insights into potential therapeutic strategies for AD and related cognitive disorders.

Epigenetic regulation of iron metabolism and ferroptosis in Parkinson's disease: Identifying novel epigenetic targets

Parkinson's disease (PD) is a neurodegenerative disease, and emerging evidence has shown that iron deposition, ferroptosis and epigenetic modifications are implicated in the pathogenesis of PD. However, the interplay among these factors in PD has not been fully understood. In this review, we provide an overview of the current research progress on iron metabolism, ferroptosis and epigenetic alterations associated with PD. Furthermore, we present new frontiers concerning various epigenetic modifications related to iron metabolism and ferroptosis that might contribute to the pathology of PD. Notably, epigenetic modifications of iron metabolism and ferroptosis as both diagnostic and therapeutic targets in PD have been discussed. This opens new avenues for the regulation of iron homeostasis and ferroptosis in PD from epigenetic perspectives, and provides evidence for their potential implications in the diagnosis and treatment of PD.

Pathogenesis and therapeutic applications of microglia receptors in Alzheimer's disease

Microglia, the resident immune cells of the central nervous system, continuously monitor the brain's microenvironment through their array of specific receptors. Once brain function is altered, microglia are recruited to specific sites to perform their immune functions, including phagocytosis of misfolded proteins, cellular debris, and apoptotic cells to maintain homeostasis. When toxic substances are overproduced, microglia are over-activated to produce large amounts of pro-inflammatory cytokines, which induce chronic inflammatory responses and lead to neurotoxicity. Additionally, microglia can also monitor and protect neuronal function through microglia-neuron crosstalk. Microglia receptors are important mediators for microglia to receive external stimuli, regulate the functional state of microglia, and transmit signals between cells. In this paper, we first review the role of microglia-expressed receptors in the pathogenesis and treatment of Alzheimer's disease; moreover, we emphasize the complexity of targeting microglia for therapeutic interventions in neurodegenerative disorders to inform the discovery of new biomarkers and the development of innovative therapeutics.

AdipoRon's Impact on Alzheimer's Disease-A Systematic Review and Meta-Analysis

Alzheimer's disease (AD) remains a leading cause of cognitive decline and mortality worldwide, characterized by neurodegeneration, synaptic deficiencies, and neuroinflammation. Despite advancements in early detection, diagnosis, and treatment, AD presents substantial challenges due to its complex pathology, heterogeneity, and the limited efficacy of current therapies. Consequently, there is a pressing need for novel therapeutic agents to target the multifaceted aspects of AD pathology, enhance current treatments, and minimize adverse effects. AdipoRon, an adiponectin receptor agonist, has garnered interest for its potential neuroprotective effects, including reducing neuroinflammation, improving mitochondrial function, and mitigating tau hyperphosphorylation. This review aimed to evaluate the effects of AdipoRon-based adiponectin replacement therapy against AD, using a comprehensive approach grounded in the PICO framework-Population, Intervention, Comparison, and Outcomes. A total of six studies were reviewed, including in vitro and in vivo investigations examining AdipoRon's impact on various AD models. These studies involved different cell lines and transgenic mouse models, assessing various outcomes such as cognitive function, neuroinflammation, tau phosphorylation, synaptic deficiencies, and relevant molecular pathways. By synthesizing data from these studies, our review thoroughly explains AdipoRon's neuroprotective effects, mechanisms of action, and potential as a therapeutic agent for AD. This analysis aims to highlight the current state of knowledge, identify gaps in the research, and suggest directions for future studies and clinical applications.