Artesunate restores mitochondrial fusion-fission dynamics and alleviates neuronal injury in Alzheimer's disease models

Cornus officinalis Sieb. Et Zucc. attenuates Aβ25-35-induced mitochondrial damage and neuroinflammation in mice by modulating the ERK pathway

BACKGROUND

Cornus officinalis Sieb. Et Zucc. has the efficacy of tonifying the marrow and filling up the essence, breaking up the accumulation and opening up the orifices. Our research team found that CoS extracts were protective against Aβ25-35-induced memory impairment in mice. However, the pharmacodynamic components and mechanisms by which CoS improves AD have yet to be thoroughly explored and investigated.

PURPOSE

This study focused on exploring the bioactive components and pharmacodynamic mechanisms of CoS aqueous extract underlying mitochondrial damage and neuroinflammation to improve Aβ25-35-induced AD.

METHODS

AD mouse models were generated using Aβ25-35 brain injections. Different doses of CoS aqueous extract were orally administered to mice for 28 days. The cognitive function, neuronal and synaptic damage, mitochondrial damage (mitochondrial length, mitochondrial fusion fission-related protein expression), neuroglial activation, and immune inflammatory factor and ERK pathway-related protein levels of mice were assessed. The CoS aqueous extracts components were identified using UPLC-TQ/MS and screened for cellular activity. Midivi-1 (Drp1 inhibitor) or PD98059 (ERK inhibitor) was added to Aβ25-35-exposed PC12 cells to assess whether CoS and its active compounds mMorB and CorE regulate mitochondrial fission through ERK/Drp1. PC12-N9 cells were cocultured to investigate whether mMorB and CorE could regulate mitochondrial division through the ERK pathway to modulate neuroinflammation.

RESULTS

CoS improved exploration and memory in AD mice, reduced synaptic and mitochondrial damage in their hippocampus, and modulated disturbed mitochondrial dynamics. Moreover, CoS inhibited ERK pathway signaling and attenuated abnormal activation of glial cells and secondary immune inflammatory responses. Additionally, in vitro experiments revealed that CoS and its compounds 7β-O-methylmorroniside (mMorB) and Cornusdiridoid E (CorE) ameliorated mitochondrial injury caused by Aβ25-35 in PC12 cells through inhibition of the ERK/Drp1 pathway. Meanwhile, mMorB and CorE ameliorated cellular inflammation by inhibiting the Ras/ERK/CREB signaling pathway.

CONCLUSION

CoS aqueous extract ameliorates behavioral deficits and brain damage in Aβ25-35-induced AD mice by modulating the ERK pathway to attenuate mitochondrial damage and neuroinflammation, and the compounds mMorB and CorE are the therapeutically active ingredients.

Another Use for a Proven Drug: Experimental Evidence for the Potential of Artemisinin and Its Derivatives to Treat Alzheimer's Disease

Plant-derived multitarget compounds may represent a promising therapeutic strategy for multifactorial diseases, such as Alzheimer's disease (AD). Artemisinin and its derivatives were indicated to beneficially modulate various aspects of AD pathology in different AD animal models through the regulation of a wide range of different cellular processes, such as energy homeostasis, apoptosis, proliferation and inflammatory pathways. In this review, we aimed to provide an up-to-date overview of the experimental evidence documenting the neuroprotective activities of artemi-sinins to underscore the potential of these already-approved drugs for treating AD also in humans and propose their consideration for carefully designed clinical trials. In particular, the benefits to the main pathological hallmarks and events in the pathological cascade throughout AD development in different animal models of AD are summarized. Moreover, dose- and context-dependent effects of artemisinins are noted.

Natural compounds modulating mitophagy: Implications for cancer therapy

Cancer is considered as the second leading cause of mortality, and cancer incidence is still growing rapidly worldwide, which poses an increasing global health burden. Although chemotherapy is the most widely used treatment for cancer, its effectiveness is limited by drug resistance and severe side effects. Mitophagy is the principal mechanism that degrades damaged mitochondria via the autophagy/lysosome pathway to maintain mitochondrial homeostasis. Emerging evidence indicates that mitophagy plays crucial roles in tumorigenesis, particularly in cancer therapy. Mitophagy can exhibit dual effects in cancer, with both cancer-inhibiting or cancer-promoting function in a context-dependent manner. A variety of natural compounds have been found to affect cancer cell death and display anticancer properties by modulating mitophagy. In this review, we provide a systematic overview of mitophagy signaling pathways, and examine recent advances in the utilization of natural compounds for cancer therapy through the modulation of mitophagy. Furthermore, we address the inquiries and challenges associated with ongoing investigations concerning the application of natural compounds in cancer therapy based on mitophagy. Overcoming these limitations will provide opportunities to develop novel interventional strategies for cancer treatment.

Oxygen metabolism abnormality and Alzheimer's disease: An update

Oxygen metabolism abnormality plays a crucial role in the pathogenesis of Alzheimer's disease (AD) via several mechanisms, including hypoxia, oxidative stress, and mitochondrial dysfunction. Hypoxia condition usually results from living in a high-altitude habitat, cardiovascular and cerebrovascular diseases, and chronic obstructive sleep apnea. Chronic hypoxia has been identified as a significant risk factor for AD, showing an aggravation of various pathological components of AD, such as amyloid β-protein (Aβ) metabolism, tau phosphorylation, mitochondrial dysfunction, and neuroinflammation. It is known that hypoxia and excessive hyperoxia can both result in oxidative stress and mitochondrial dysfunction. Oxidative stress and mitochondrial dysfunction can increase Aβ and tau phosphorylation, and Aβ and tau proteins can lead to redox imbalance, thus forming a vicious cycle and exacerbating AD pathology. Hyperbaric oxygen therapy (HBOT) is a non-invasive intervention known for its capacity to significantly enhance cerebral oxygenation levels, which can significantly attenuate Aβ aggregation, tau phosphorylation, and neuroinflammation. However, further investigation is imperative to determine the optimal oxygen pressure, duration of exposure, and frequency of HBOT sessions. In this review, we explore the prospects of oxygen metabolism in AD, with the aim of enhancing our understanding of the underlying molecular mechanisms in AD. Current research aimed at attenuating abnormalities in oxygen metabolism holds promise for providing novel therapeutic approaches for AD.

Advances in the pharmacological study of Chinese herbal medicine to alleviate diabetic nephropathy by improving mitochondrial oxidative stress

Diabetic nephropathy (DN) is one of the serious complications of diabetes mellitus, primarily arising from type 2 diabetes (T2DM), and can progress to chronic kidney disease (CKD) and end stage renal disease (ESRD). The pathogenesis of DN involves various factors such as hemodynamic changes, oxidative stress, inflammatory response, and lipid metabolism disorders. Increasing attention is being given to DN caused by oxidative stress in the mitochondrial pathway, prompting researchers to explore drugs that can regulate these target pathways. Chinese herbal medicine, known for its accessibility, rich historical usage, and remarkable efficacy, has shown promise in ameliorating renal injury caused by DN by modulating oxidative stress in the mitochondrial pathway. This review aims to provide a reference for the prevention and treatment of DN. Firstly, we outline the mechanisms by which mitochondrial dysfunction impairs DN, focusing on outlining the damage to mitochondria by oxidative stress. Subsequently, we describe the process by which formulas, herbs and monomeric compounds protect the kidney by ameliorating oxidative stress in the mitochondrial pathway. Finally, the rich variety of Chinese herbal medicine, combined with modern extraction techniques, has great potential, and as we gradually understand the pathogenesis of DN and research techniques are constantly updated, there will be more and more promising therapeutic targets and herbal drug candidates. This paper aims to provide a reference for the prevention and treatment of DN.

Alzheimer's disease and neuroinflammation: will new drugs in clinical trials pave the way to a multi-target therapy?

Despite extensive research, no disease-modifying therapeutic option, able to prevent, cure or halt the progression of Alzheimer's disease [AD], is currently available. AD, a devastating neurodegenerative pathology leading to dementia and death, is characterized by two pathological hallmarks, the extracellular deposits of amyloid beta (Aβ) and the intraneuronal deposits of neurofibrillary tangles (NFTs) consisting of altered hyperphosphorylated tau protein. Both have been widely studied and pharmacologically targeted for many years, without significant therapeutic results. In 2022, positive data on two monoclonal antibodies targeting Aβ, donanemab and lecanemab, followed by the 2023 FDA accelerated approval of lecanemab and the publication of the final results of the phase III Clarity AD study, have strengthened the hypothesis of a causal role of Aβ in the pathogenesis of AD. However, the magnitude of the clinical effect elicited by the two drugs is limited, suggesting that additional pathological mechanisms may contribute to the disease. Cumulative studies have shown inflammation as one of the main contributors to the pathogenesis of AD, leading to the recognition of a specific role of neuroinflammation synergic with the Aβ and NFTs cascades. The present review provides an overview of the investigational drugs targeting neuroinflammation that are currently in clinical trials. Moreover, their mechanisms of action, their positioning in the pathological cascade of events that occur in the brain throughout AD disease and their potential benefit/limitation in the therapeutic strategy in AD are discussed and highlighted as well. In addition, the latest patent requests for inflammation-targeting therapeutics to be developed in AD will also be discussed.

Retinal safety and toxicity study of artesunate in vitro and in vivo

Background

Artesunate (ART), a member of the artemisinin family, possesses multi-properties, including anti-inflammation, anti-oxidation, and anti-tumor. ART was recently reported to show anti-neovascularization effect on the cornea, iris, and retina. Compared to the expensive anti-VEGF treatment, this versatile, economical treatment option is attractive in the ophthalmic field. The safety and toxicity profile of ART intravitreal application are in utmost need.

Methods

In this study, immortalized microglial (IMG) cells were treated with ART to determine the safe concentrations without inducing overt inflammatory reactions. Reverse transcription-polymerase chain reaction analysis was used to detect the cytokine expressions in IMG cells in response to ART stimulation. Various doses of ART were intravitreally injected into the right eyes of C57BL/6 mice. Retinal function was tested by electroretinogram, and retinal ganglion cell (RGC) survival was evaluated by counting Brn3a stained cells in flat-mounted retinas at 7 days after ART injection.

Results

ART below 5μM was safe for IMG cells in vitro. Both 2.5 and 5 ​μM ART treatment increased IL-10 gene expression in IMG cells while not changing IL-1β, IL-6, TNF-α, and Arg-1. In the in vivo study, intravitreal injection of ART below 100 ​μM did not cause deterioration in the retinal function and RGC survival of the mouse eyes, while 1 ​mM ART treatment significantly attenuated both the scotopic and photopic b-wave amplitudes and impaired RGC survival. In addition, treatment with ART of 25, 50, and 100 ​μM significantly decreased TNF-α gene expression while ART of 100 ​μM significantly increased IL-10 in the mouse retina.

Conclusions

Intravitreal injection of 100 ​μM ART could downregulate TNF-α while upregulate IL-10 in the mouse retina without causing retinal functional deterioration and RGC loss. ART might be used as anti-inflammatory agent for retinal disorders.

AdipoRon mitigates tau pathology and restores mitochondrial dynamics via AMPK-related pathway in a mouse model of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a complicated and refractory neurodegenerative disease that is typically characterized by memory loss and multiple cognitive impairments. Multiple neuropathology including hyperphosphorylated tau formation and accumulation, dysregulated mitochondrial dynamics, and synaptic damage have been well implicated in the progression of AD. So far, there are few valid and effective therapeutic modalities for treatment. AdipoRon, a specific adiponectin (APN) receptor agonist, is reported to be associated with cognitive deficits improvement. In the present study, we attempt to explore the potential therapeutic effects of AdipoRon on tauopathy and related molecular mechanisms.

METHODS

In this study, P301S tau transgenic mice were used. The plasma level of APN was detected by ELISA. The level of APN receptors was qualified by western blot and immunofluorescence. 6-month-old mice were treated with AdipoRon or vehicle by oral administration daily for 4 months. The benefits of AdipoRon on tau hyperphosphorylation, mitochondrial dynamics, and synaptic function were detected by western blot, immunohistochemistry, immunofluorescence, Golgi staining and transmission electron microscopy. Morris water maze test and novel object recognition test were conducted to explore memory impairments.

RESULTS

Compared with wild-type mice, the expression of APN in plasma in 10-month-old P301S mice was obviously decreased. APN receptors in the hippocampus were increased in the hippocampus. AdipoRon treatment significantly rescued memory deficits in P301S mice. Besides, AdipoRon treatment was also detected to improve synaptic function, enhance mitochondrial fusion, and mitigate hyperphosphorylated tau accumulation in P301S mice and SY5Y cells. Mechanistically, AMPK/SIRT3 and AMPK/GSK3β signaling pathways are demonstrated to be involved in AdipoRon-mediated benefits on mitochondrial dynamics and tau accumulation, respectively, and inhibition of AMPK related pathways showed counteracted effects.

CONCLUSION

Our results demonstrated that AdipoRon treatment could significantly mitigate tau pathology, improve synaptic damage, and restore mitochondrial dynamics via the AMPK-related pathway, which provides a novel potential therapeutic approach to retard the progression of AD and other tauopathies diseases.

Loss of Extrasynaptic Inhibitory Glycine Receptors in the Hippocampus of an AD Mouse Model Is Restored by Treatment with Artesunate

Alzheimer's disease (AD) is characterized by synaptic failure and neuronal loss. Recently, we demonstrated that artemisinins restored the levels of key proteins of inhibitory GABAergic synapses in the hippocampus of APP/PS1 mice, a model of cerebral amyloidosis. In the present study, we analyzed the protein levels and subcellular localization of α2 and α3 subunits of GlyRs, indicated as the most abundant receptor subtypes in the mature hippocampus, in early and late stages of AD pathogenesis, and upon treatment with two different doses of artesunate (ARS). Immunofluorescence microscopy and Western blot analysis demonstrated that the protein levels of both α2 and α3 GlyRs are considerably reduced in the CA1 and the dentate gyrus of 12-month-old APP/PS1 mice when compared to WT mice. Notably, treatment with low-dose ARS affected GlyR expression in a subunit-specific way; the protein levels of α3 GlyR subunits were rescued to about WT levels, whereas that of α2 GlyRs were not affected significantly. Moreover, double labeling with a presynaptic marker indicated that the changes in GlyR α3 expression levels primarily involve extracellular GlyRs. Correspondingly, low concentrations of artesunate (≤1 µM) also increased the extrasynaptic GlyR cluster density in hAPPswe-transfected primary hippocampal neurons, whereas the number of GlyR clusters overlapping presynaptic VIAAT immunoreactivities remained unchanged. Thus, here we provide evidence that the protein levels and subcellular localization of α2 and α3 subunits of GlyRs show regional and temporal alterations in the hippocampus of APP/PS1 mice that can be modulated by the application of artesunate.

Inhibition of VDAC1 Rescues Aβ 1-42-Induced Mitochondrial Dysfunction and Ferroptosis via Activation of AMPK and Wnt/β-Catenin Pathways

Beta-amyloid (Aβ) accumulation in the brains of Alzheimer's disease (AD) patients leads to mitochondrial dysfunction and ferroptosis in neurons. Voltage-dependent anion channel 1 (VDAC1) is a major protein in the mitochondrial outer membrane. It has been reported that VDAC1 associated with mitochondrial dysfunction and ferroptosis. However, the mechanism by which VDAC1 regulates mitochondrial dysfunction and ferroptosis of neurons in AD remains unclear. This study is aimed at investigating the mechanism of action of VDAC1 in mitochondrial dysfunction and ferroptosis in neurons of the AD model. In this study, we determined cell viability after treatment with Aβ _1-42 via the MTT assay. The SOD, MDA, ROS, and MMP production was measured via the SOD kit, MDA kit, DCFDA staining, and JC-1 staining. The memory abilities of mice were detected via the Morris water maze test. The expression of AMPK/mTOR, Wnt/β-catenin, and GPX4 regulated by VDAC1 was detected via western blotting. Our present study showed that PC12 cells had decreased cell viability, increased LDH release, and decreased GPX4 expression after Aβ _1-42 treatment. Meanwhile, Aβ _1-42 induced MMP and SOD downregulation and increased MDA and ROS generation in PC12 cells. In addition, the expression of VDAC1 is increased in the brain tissue of AD mice and Aβ _1-42-treated PC12 cells. Further investigation of the role of VDAC1 in regulating AD found that all effects induced by Aβ _1-42 were reversed by inhibition of VDAC1. Additionally, inhibition of VDAC1 activates the AMPK/mTOR and Wnt/β-catenin pathways. Taken together, these findings demonstrate that inhibition of VDAC1 alleviates mitochondrial dysfunction and ferroptosis in AD neurons by activating AMPK/mTOR and Wnt/β-catenin.

Therapeutic potential of artemisinin and its derivatives in managing kidney diseases

Artemisinin, an antimalarial traditional Chinese herb, is isolated from Artemisia annua. L, and has shown fewer side effects. Several pieces of evidence have demonstrated that artemisinin and its derivatives exhibited therapeutic effects on diseases like malaria, cancer, immune disorders, and inflammatory diseases. Additionally, the antimalarial drugs demonstrated antioxidant and anti-inflammatory activities, regulating the immune system and autophagy and modulating glycolipid metabolism properties, suggesting an alternative for managing kidney disease. This review assessed the pharmacological activities of artemisinin. It summarized the critical outcomes and probable mechanism of artemisinins in treating kidney diseases, including inflammatory, oxidative stress, autophagy, mitochondrial homeostasis, endoplasmic reticulum stress, glycolipid metabolism, insulin resistance, diabetic nephropathy, lupus nephritis, membranous nephropathy, IgA nephropathy, and acute kidney injury, suggesting the therapeutic potential of artemisinin and its derivatives in managing kidney diseases, especially the podocyte-associated kidney diseases.

The contribution of mitochondria-associated endoplasmic reticulum membranes (MAMs) dysfunction in Alzheimer's disease and the potential countermeasure

Alzheimer's disease (AD) is the most common neurodegenerative disease. There are many studies targeting extracellular deposits of amyloid β-peptide (Aβ) and intracellular neurofibrillary tangles (NFTs), however, there are no effective treatments to halt the progression. Mitochondria-associated endoplasmic reticulum membranes (MAMs) have long been found to be associated with various pathogenesis hypotheses of AD, such as Aβ deposition, mitochondrial dysfunction, and calcium homeostasis. However, there is a lack of literature summarizing recent advances in the mechanism and treatment studies. Accordingly, this article reviews the latest research involving the roles of MAM structure and tethering proteins in the pathogenesis of AD and summarizes potential strategies targeting MAMs to dissect treatment perspectives for AD.