Neuroprotective effects of verbascoside against Alzheimer's disease via the relief of endoplasmic reticulum stress in Aβ-exposed U251 cells and APP/PS1 mice

Ferroptosis pathways: Unveiling the neuroprotective power of cistache deserticola phenylethanoid glycosides

ETHNOPHARMACOLOGICAL RELEVANCE

Cistanche deserticola is a kind of parasitic plant living in the roots of desert trees. It is a rare Chinese medicine, which has the effect of tonifying kidney Yang, benefiting essence and blood and moistening the intestinal tract. Cistache deserticola phenylethanoid glycoside (PGS), an active component found in Cistanche deserticola Ma, have potential kidney tonifying, intellectual enhancing, and neuroprotective effects. Cistanche total glycoside capsule has been marketed to treat vascular dementia disease.

AIM OF THE STUDY

To identify the potential renal, intellectual enhancing and neuroprotective effects of PGS and explore the exact targets and mechanisms of PGS.

MATERIALS AND METHODS

This study systematically investigated the four types of pathways leading to ferroptosis through transcriptome, metabolome, ultrastructure and molecular biology techniques and explored the molecular mechanism by which multiple PGS targets and pathways synergistically exert neuroprotective effects on hypoxia.

RESULTS

PGS alleviated learning and memory dysfunction and pathological injury in mice exposed to hypobaric hypoxia by attenuating hypobaric hypoxia-induced hippocampal histopathological damage, impairing blood‒brain barrier integrity, increasing oxidative stress levels, and increasing the expression of cognitive proteins. PGS reduced the formation of lipid peroxides and improved ferroptosis by upregulating the GPX-4/SCL7A311 axis and downregulating the ACSL4/LPCAT3/LOX axis. PGS also reduced ferroptosis by facilitating cellular Fe2+ efflux and regulating mitochondrial Fe2+ transport and effectively antagonized cell ferroptosis induced by erastin (a ferroptosis inducer).

CONCLUSIONS

This study demonstrated the mechanism by which PGS prevents hypobaric hypoxic nerve injury through four types of ferroptosis pathways, achieved neuroprotective effects and alleviated learning and memory dysfunction in hypobaric hypoxia mice. This study provides a theoretical basis for the development and application of PGS.

Ferroptosis mechanism and Alzheimer's disease

Regulated cell death is a genetically determined form of programmed cell death that commonly occurs during the development of living organisms. This process plays a crucial role in modulating homeostasis and is evolutionarily conserved across a diverse range of living organisms. Ferroptosis is a classic regulatory mode of cell death. Extensive studies of regulatory cell death in Alzheimer's disease have yielded increasing evidence that ferroptosis is closely related to the occurrence, development, and prognosis of Alzheimer's disease. This review summarizes the molecular mechanisms of ferroptosis and recent research advances in the role of ferroptosis in Alzheimer's disease. Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for Alzheimer's disease.

Acteoside alleviates lipid peroxidation by enhancing Nrf2-mediated mitophagy to inhibit ferroptosis for neuroprotection in Parkinson's disease

Increasing evidence underscores the pivotal role of ferroptosis in Parkinson's Disease (PD) pathogenesis. Acteoside (ACT) has been reported to possess neuroprotective properties. However, the effects of ACT on ferroptosis and its molecular mechanisms remain unknown. This study aimed to explore whether ACT can regulate ferroptosis in dopaminergic (DA) neurons within both in vitro and in vivo PD models and to elucidate the underlying regulatory mechanisms. PD models were established and treated with various concentrations of ACT. Cell viability assays, Western blot, lipid peroxidation assessments, immunohistochemistry, and transmission electron microscopy were employed to confirm ACT's inhibition of ferroptosis and its protective effect on DA neurons across PD models. Immunofluorescence staining, MitoSOX staining, and confocal laser scanning microscopy further validated ACT's regulation regulatory effects on ferroptosis via the Nrf2-mitophagy pathway. Four animal behavioral tests were used to assess behavioral improvements in PD animals. ACT inhibited ferroptosis in PD models in vitro, as evidenced by increased cell viability, the upregulation of GPX4 and SLC7A11, reduced lipid peroxides, and attenuation of mitochondrial morphological alterations typical of ferroptosis. By activating the Nrf2-mitophagy axis, ACT enhanced mitochondrial integrity and reduced lipid peroxidation, mitigating ferroptosis. These in vitro results were consistent with in vivo findings, where ACT treatment significantly preserved DA neurons, curbed ferroptosis in these cells, and alleviated cognitive and behavioral deficits. This study is the first demonstration of ACT's capability to inhibit neuronal ferroptosis and protect DA neurons, thus alleviating behavioral and cognitive impairments in both in vitro and in vivo PD models. Furthermore, The suppression of ferroptosis by ACT is achieved through the activation of the Nrf2-mitophagy signaling pathway. Our results show that ACT is beneficial for both treating and preventing PD. They also offer novel therapeutic options for treating PD and molecular targets for regulating ferroptosis.

Unveiling the impact of aging on BBB and Alzheimer's disease: Factors and therapeutic implications

Alzheimer's disease (AD) is a highly prevalent neurodegenerative condition that has devastating effects on individuals, often resulting in dementia. AD is primarily defined by the presence of extracellular plaques containing insoluble β-amyloid peptide (Aβ) and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau). In addition, individuals afflicted by these age-related illnesses experience a diminished state of health, which places significant financial strain on their loved ones. Several risk factors play a significant role in the development of AD. These factors include genetics, diet, smoking, certain diseases (such as cerebrovascular diseases, obesity, hypertension, and dyslipidemia), age, and alcohol consumption. Age-related factors are key contributors to the development of vascular-based neurodegenerative diseases such as AD. In general, the process of aging can lead to changes in the immune system's responses and can also initiate inflammation in the brain. The chronic inflammation and the inflammatory mediators found in the brain play a crucial role in the dysfunction of the blood-brain barrier (BBB). Furthermore, maintaining BBB integrity is of utmost importance in preventing a wide range of neurological disorders. Therefore, in this review, we discussed the role of age and its related factors in the breakdown of the blood-brain barrier and the development of AD. We also discussed the importance of different compounds, such as those with anti-aging properties, and other compounds that can help maintain the integrity of the blood-brain barrier in the prevention of AD. This review builds a strong correlation between age-related factors, degradation of the BBB, and its impact on AD.

Plant-derived bioactive compounds and their novel role in central nervous system disorder treatment via ATF4 targeting: A systematic literature review

Central nervous system (CNS) disorders exhibit exceedingly intricate pathogenic mechanisms. Pragmatic and effective solutions remain elusive, significantly compromising human life and health. Activating transcription factor 4 (ATF4) participates in the regulation of multiple pathophysiological processes, including CNS disorders. Considering the widespread involvement of ATF4 in the pathological process of CNS disorders, the targeted regulation of ATF4 by plant-derived bioactive compounds (PDBCs) may become a viable strategy for the treatment of CNS disorders. However, the regulatory relationship between PDBCs and ATF4 remains incompletely understood. Here, we aimed to comprehensively review the studies on PDBCs targeting ATF4 to ameliorate CNS disorders, thereby offering novel directions and insights for the treatment of CNS disorders. A computerized search was conducted on PubMed, Embase, Web of Science, and Google Scholar databases to identify preclinical experiments related to PDBCs targeting ATF4 for the treatment of CNS disorders. The search timeframe was from the inception of the databases to December 2023. Two assessors conducted searches using the keywords "ATF4," "Central Nervous System," "Neurological," "Alzheimer's disease," "Parkinson's Disease," "Stroke," "Spinal Cord Injury," "Glioblastoma," "Traumatic Brain Injury," and "Spinal Cord Injury." Overall, 31 studies were included, encompassing assessments of 27 PDBCs. Combining results from in vivo and in vitro studies, we observed that these PDBCs, via ATF4 modulation, prevent the deposition of amyloid-like fibers such as Aβ, tau, and α-synuclein. They regulate ERS, reduce the release of inflammatory factors, restore mitochondrial membrane integrity to prevent oxidative stress, regulate synaptic plasticity, modulate autophagy, and engage anti-apoptotic mechanisms. Consequently, they exert neuroprotective effects in CNS disorders. Numerous PDBCs targeting ATF4 have shown potential in facilitating the restoration of CNS functionality, thereby presenting expansive prospects for the treatment of such disorders. However, future endeavors necessitate high-quality, large-scale, and comprehensive preclinical and clinical studies to further validate this therapeutic potential.

Neuroprotective effects of acteoside in a glaucoma mouse model by targeting Serta domain-containing protein 4

AIM

To explore the therapeutic effect and main molecular mechanisms of acteoside in a glaucoma model in DBA/2J mice.

METHODS

Proteomics was used to compare the differentially expressed proteins of C57 and DBA/2J mice. After acteoside administration in DBA/2J mice, anterior segment observation, intraocular pressure (IOP) monitoring, electrophysiology examination, and hematoxylin and eosin staining were used to analyze any potential effects. Immunohistochemistry (IHC) assays were used to verify the proteomics results. Furthermore, retinal ganglion cell 5 (RGC5) cell proliferation was assessed with cell counting kit-8 (CCK-8) assays. Serta domain-containing protein 4 (Sertad4) mRNA and protein expression levels were measured by qRT-PCR and Western blot analysis, respectively.

RESULTS

Proteomics analysis suggested that Sertad4 was the most significantly differentially expressed protein. Compared with the saline group, the acteoside treatment group showed decreased IOP, improved N1-P1 wave amplitudes, thicker retina, and larger numbers of cells in the ganglion cell layer (GCL). The IHC results showed that Sertad4 expression levels in DBA/2J mice treated with acteoside were significantly lower than in the saline group. Acteoside treatment could improve RGC5 cell survival and reduce the Sertad4 mRNA and protein expression levels after glutamate injury.

CONCLUSION

Sertad4 is differentially expressed in DBA/2J mice. Acteoside can protect RGCs from damage, possibly through the downregulation of Sertad4, and has a potential use in glaucoma treatment.

Natural polyphenol: Their pathogenesis-targeting therapeutic potential in Alzheimer's disease

Alzheimer's disease (AD) is a detrimental neurodegenerative disease affecting the elderly. Clinically, it is characterized by progressive memory decline and subsequent loss of broader cognitive functions. Current drugs provide only symptomatic relief but do not have profound disease-modifying effects. There is an unmet need to identify novel pharmacological agents for AD therapy. Neuropathologically, the characteristic hallmarks of the disease are extracellular senile plaques containing amyloid β-peptides and intracellular neurofibrillary tangles containing hyperphosphorylated microtubule-associated protein tau. Simultaneously, oxidative stress, neuroinflammation and mitochondrial dysfunction in specific brain regions are early events during the process of AD pathologic changes and are associated with Aβ/tau toxicity. Here, we first summarized probable pathogenic mechanisms leading to neurodegeneration and hopefully identify pathways that serve as specific targets to improve therapy for AD. We then reviewed the mechanisms that underlie disease-modifying effects of natural polyphenols, with a focus on nuclear factor erythroid 2-related factor 2 activators for AD treatment. Lastly, we discussed challenges in the preclinical to clinical translation of natural polyphenols. In conclusion, there is evidence that natural polyphenols can be therapeutically useful in AD through their multifaceted mechanism of action. However, more clinical studies are needed to confirm these effects.

The protective effect of methanolic extract of Verbascum cheiranthifolium and Biebersteinia multifida DC on hippocampus damage induced by diazinon in male Wistar rats: An experimental study

Diazinon (DZN) an organophosphate (OP), with the most important mechanism of action of DZN being induction of oxidative stress (OS) and inhibition of the enzyme acetylcholinesterase (AChE). Verbascum cheiranthifolium (VER) and Biebersteinia multifida (BM) belong to the Scrophulariaceae and Biebersteiniaceae family respectively. These plants are widely used in Iranian traditional medicine due to their beneficial effects. Thus, this research aimed to appraise the protective effects of the methanolic extract of the VER and BM on changes in the level of expression of α7 and α4 subunits of nicotinic acetylcholine receptors (nAChRs) in hippocampus (HPC) of DZN-treated rats. In this research, 36 male Wistar rats were used and randomly divided into six groups: Control, DZN (40 mg/kg), VER (1 g/kg), DZN+VER (40 mg/kg+1 g/kg), BM (150 mg/kg), and DZN+BM (40 mg/kg+150 mg/kg). At the end of treatment periods, the animals of all groups underwent the Morris water maze (MWM) test. The rats were anesthetized, and blood sampling was performed. Eventually, the brain was removed for histological study and evaluation of OS parameters. The results indicated that DZN increased the extent of expression of nAChRs in the HPC and significantly inhibited cholinesterase (ChEs) activity plus OS parameters. Also, in MWM, the time to find the platform was significantly longer in the DZN group, while the time and the distance in the probe test were lower than in the control groups. VER and BM extract in the treatment groups simultaneously improved the extent of expression of nAChRs, ChEs activity, as well as the parameters of OS and spatial memory significantly. In conclusion, our results support the neuroprotective properties of VER and BM extract versus DZN in rats. Accordingly, the extracts of VER and BM may be useful as an approach for the treatment of learning disorders and memory enhancement.

Structural characterization of Russula griseocarnosa polysaccharide and its improvement on hematopoietic function

The hematopoietic function of a polysaccharide derived from Russula griseocarnosa was demonstrated in K562 cells, and subsequently purified through chromatography to obtain RGP1. RGP1 is a galactan composed of 1,6-α-D-Galp as the main chain, with partial substitutions. A -CH3 substitution was detected at O-3 of 1,6-α-D-Galp. The possible branches at O-2 of 1,6-α-D-Galp was α-L-Fucp. In mice with cyclophosphamide (CTX)-induced hematopoietic dysfunction, RGP1 alleviated bone marrow damage and multinucleated giant cell infiltration of the spleen, increased the number of long-term hematopoietic stem cells, and regulated the levels of myeloid cells in the peripheral blood. Furthermore, RGP1 promoted the differentiation of activated T cells and CD4+ T cells without affecting natural killer cells and B cells. Proteomic analysis, detection of cytokines, and western blotting revealed that RGP1 could alleviate hematopoietic dysfunction by promoting the activation of CD4+ T cells and the Janus kinase/ signal transducer and activator of transcription 3 pathway. The present study provides experimental evidence to support the application of RGP1 in CTX-induced hematopoietic dysfunction.

Engagement of AKT and ERK signaling pathways facilitates infection of human neuronal cells with West Nile virus

West Nile virus (WNV) is an important neurotropic virus that accounts for the emergence of human arboviral encephalitis and meningitis. The interaction of WNV with signaling pathways plays a key role in controlling WNV infection. We have investigated the roles of the AKT and ERK pathways in supporting WNV propagation and modulating the inflammatory response following WNV infection. WNV established a productive infection in neuronal cell lines originated from human and mouse. Expression of IL-11 and TNF-α was markedly up-regulated in the infected human neuronal cells, indicating elicitation of inflammation response upon WNV infection. WNV incubation rapidly activated signaling cascades of AKT (AKT-S6-4E-BP1) and ERK (MEK-ERK-p90RSK) pathways. Treatment with AKT inhibitor MK-2206 or MEK inhibitor U0126 abrogated WNV-induced AKT or ERK activation. Strong activation of AKT and ERK signaling pathways could be detectable at 24 h after WNV infection, while such activation was abolished at 48 h post infection. U0126 treatment or knockdown of ERK expression significantly increased WNV RNA levels and viral titers and efficiently decreased IL-11 production induced by WNV, suggesting the involvement of ERK pathway in WNV propagation and IL-11 induction. MK-2206 treatment enhanced WNV RNA replication accompanied with a moderate decrease in IL-11 production. These results demonstrate that engagement of AKT and ERK signaling pathways facilitates viral infection and may be implicated in WNV pathogenesis.

Sestrin2 can alleviate endoplasmic reticulum stress to improve traumatic brain injury by activating AMPK/mTORC1 signaling pathway

Traumatic brain injury (TBI), as a serious central nervous system disease, can result in severe neurological dysfunction or even disability and death of patients. The early and effective intervention of secondary brain injury can improve the prognosis of TBI. Endoplasmic reticulum (ER) stress is one of the main reasons to recover TBI. ER stress inhibition may be beneficial in treating TBI. Sestrin2 is a crucial regulator of ER stress, and its activation can significantly improve TBI. In this paper, we analyze the biological function of sestrin2, the latest findings on ER stress, and the relationship between ER stress and TBI. We elucidate the relationship of sestrin2 inhibiting ER stress via activating the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (MTORC1) signaling. Finally, we elaborate on the possible role of sestrin2 in TBI and explain how its activation potentially improves TBI.

Unveiling the role of astrocytes in postoperative cognitive dysfunction

Alzheimer's disease (AD) is the most common neurodegenerative disorder, characterized by progressive cognitive decline and the accumulation of amyloid-beta plaques, tau tangles, and neuroinflammation in the brain. Postoperative cognitive dysfunction (POCD) is a prevalent and debilitating condition characterized by cognitive decline following neuroinflammation and oxidative stress induced by procedures. POCD and AD are two conditions that share similarities in the underlying mechanisms and pathophysiology. Compared to normal aging individuals, individuals with POCD are at a higher risk for developing AD. Emerging evidence suggests that astrocytes, the most abundant glial cells in the central nervous system, play a critical role in the pathogenesis of these conditions. Comprehensive functions of astrocyte in AD has been extensively explored, but very little is known about POCD may experience late-onset AD pathogenesis. Herein, in this context, we mainly explore the multifaceted roles of astrocytes in the context of POCD, highlighting their involvement in neuroinflammation, neurotransmitter regulation, synaptic plasticity and neurotrophic support, and discuss how POCD may augment the onset of AD. Additionally, we discuss potential therapeutic strategies targeting astrocytes to mitigate or prevent POCD, which hold promise for improving the quality of life for patients undergoing surgeries and against AD in the future.

The amelioration of a purified Pleurotus abieticola polysaccharide on atherosclerosis in ApoE-/- mice

In this study, a polysaccharide known as PAPS2 was eluted from Pleurotus abieticola fruiting bodies using 0.1 M NaCl solutions. PAPS2 has a Mw of 19.64 kDa and its backbone is mainly composed of →6)-α-D-Galp-(1→, →6)-β-D-Glcp-(1→ and →2,6)-α-D-Galp-(1→ residues, and its branches mainly end with β-D-Manp-(1→, which is attached at C2 of →2,6)-α-D-Galp-(1→. PAPS2 elicited several effects in high-fat diet (HFD)-fed ApoE-/- mice. It significantly reduced the body weight, liver index, and serum levels of total cholesterol (TC) and triglycerides (TGs), and it alleviated lipid accumulation in the aorta. Intestinal microflora analysis showed that PAPS2 suppressed the abundances of Adlercreutzia, Turicibacter, and Helicobacter and enriched that of Roseburia. It also influenced lipid metabolism, suggesting that it reduced the levels of TGs, lysophosphatidylcholine (LPC), phosphatidylcholine (PC), and ceramide (Cer). Moreover, it suppressed oxidative response by increasing nuclear factor erythroid 2 (Nrf2)-related factor expression and activating the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) to reduce the level of reactive oxygen species (ROS). Meanwhile, it showed anti-inflammatory effects partially related to the inhibition of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling induced by lipopolysaccharide (LPS) in RAW 264.7 cells, as well as in the aorta of HFD-fed ApoE-/- mice. This study provides experimental evidence of the auxiliary applicability of PAPS2 in atherosclerosis treatment.

Verbascoside-Rich Plant Extracts in Animal Nutrition

In recent years, the search for dietary intervention with natural products able to sustain animal health and decrease environmental impact, has raised the number of studies pertaining to the use of plants' secondary metabolites. In fact, in livestock, there is a clear relationship between the animals' antioxidant status and the onset of some diseases that negatively affect animal welfare, health, and productive performance. An interesting compound that belongs to the secondary metabolites family of plants, named phenylpropanoids, is verbascoside. The genus Verbascum, which includes more than 233 plant species, is the genus in which this compound was first identified, but it has also been found in other plant extracts. Verbascoside exhibits several properties such as antioxidant, anti-inflammatory, chemopreventive, and neuroprotective properties, that have been evaluated mainly in in vitro studies for human health. The present work reviews the literature on the dietary integration of plant extracts containing verbascoside in livestock. The effects of dietary plant extracts containing verbascoside on the productive performance, antioxidant status, blood parameters, and meat quality in several animal species were evaluated. The present data point out that dietary plant extracts containing verbascoside appear to be a favorable dietary intervention to enhance health, antioxidant status, and product quality in livestock.

Verbascoside: A neuroprotective phenylethanoid glycosides with anti-depressive properties

BACKGROUND

Verbascoside is a natural and water-soluble phenylethanoid glycoside found in several medicinal plants. It has extensive pharmacological effects, including antioxidative and antineoplastic actions, and a wide range of therapeutic effects against depression.

PURPOSE

In this review, we appraised preclinical and limited clinical evidence to fully discuss the anti-depression capacity of verbascoside and its holistic characteristics that can contribute to better management of depression in vivo and in vitro models, as well as, its toxicities and medicinal value.

METHODS

This review was prepared according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A systematic review of 32 preclinical trials published up to April 2023, combined with a comprehensive bioinformatics analysis of network pharmacology and molecular docking, was conducted to elucidate the antidepressant mechanism of action of verbascoside. Studies included in the systematic review were obtained from 7 electronic databases: PubMed, Scopus, Web of Science, Cochrane, ResearchGate, ScienceDirect, and Google Scholar.

RESULTS

Studies on the antidepressant effects of verbascoside showed that various pharmacological mechanisms and pathways, such as modulating the levels of monoamine neurotransmitters, inhibiting hypothalamic-pituitary-adrenal (HPA) axis hyperfunction and promoting neuroprotection may be involved in the process of its action against depression. Verbascoside promotes dopamine (DA) biosynthesis by promoting the expression of tyrosine hydroxylase mRNA and protein, upregulates the expression of 5-hydroxytryptamine receptor 1B (5-HT1B), prominence protein, microtubule-associated protein 2 (MAP2), hemeoxygenase-1 (HO-1), SQSTM1, Recombinant Autophagy Related Protein 5 (ATG5) and Beclin-1, and decreases the expression of caspase-3 and a-synuclein, thus exerting antidepressant effects. We identified seven targets (CCL2, FOS, GABARAPL1, CA9, TYR, CA12, and SQSTM1) and three signaling pathways (glutathione metabolism, metabolism of xenobiotics by cytochrome P450, fluid shear stress and atherosclerosis) as potential molecular biological sites for verbascoside.

CONCLUSIONS

These findings provide strong evidence that verbascoside exerts its antidepressant effects through various pharmacological mechanisms. However, further multicentre clinical case-control and molecularly targeted fishing studies are required to confirm the clinical efficacy of verbascoside and its underlying direct targets.

Ferroptosis, Pyroptosis, and Cuproptosis in Alzheimer's Disease

Alzheimer's disease (AD), the most common type of dementia, is a neurodegenerative disorder characterized by progressive cognitive dysfunction. Epidemiological investigation has demonstrated that, after cardiovascular and cerebrovascular diseases, tumors, and other causes, AD has become a major health issue affecting elderly individuals, with its mortality rate acutely increasing each year. Regulatory cell death is the active and orderly death of genetically determined cells, which is ubiquitous in the development of living organisms and is crucial to the regulation of life homeostasis. With extensive research on regulatory cell death in AD, increasing evidence has revealed that ferroptosis, pyroptosis, and cuproptosis are closely related to the occurrence, development, and prognosis of AD. This paper will review the molecular mechanisms of ferroptosis, pyroptosis, and cuproptosis and their regulatory roles in AD to explore potential therapeutic targets for the treatment of AD.

Exploring the therapeutic potential of natural compounds for Alzheimer's disease: Mechanisms of action and pharmacological properties

Alzheimer's Disease (AD) is a global public health priority characterized by high mortality rates in adults and an increasing prevalence in aging populations worldwide. Despite significant advancements in comprehending the pathogenesis of AD since its initial report in 1907, there remains a lack of effective curative or preventive measures for the disease. In recent years, natural compounds sourced from diverse origins have garnered considerable attention as potential therapeutic agents for AD, owing to their anti-inflammatory, antioxidant, and neuroprotective properties. This review aims to consolidate the therapeutic effects of natural compounds on AD, specifically targeting the reduction of β-amyloid (Aβ) overproduction, anti-apoptosis, autophagy, neuroinflammation, oxidative stress, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Notably, the identified compounds exhibiting these effects predominantly originate from plants. This review provides valuable insights into the potential of natural compounds as a reservoir of novel therapeutic agents for AD, thereby stimulating further research and contributing to the development of efficacious treatments for this devastating disease.

Neuromodulatory effect of vardenafil on aluminium chloride/D-galactose induced Alzheimer's disease in rats: emphasis on amyloid-beta, p-tau, PI3K/Akt/p53 pathway, endoplasmic reticulum stress, and cellular senescence

Dysregulation of protein homeostasis, proteostasis, is a distinctive hallmark of many neurodegenerative disorders and aging. Deleteriously, the accumulation of aberrant proteins in Alzheimer's disease (AD) is accompanied with a marked collapse in proteostasis network. The current study explored the potential therapeutic effect of vardenafil (VAR), a phosphodiesterase-5 inhibitor, in AlCl3/D-galactose (D-gal)-induced AD in rats and its possible underlying mechanisms. The impact of VAR treatment on neurobehavioral function, hippocampal tissue architecture, and the activity of the cholinergic system main enzymes were assessed utilizing VAR at doses of 0.3 mg/kg and 1 mg/kg. Additionally, the expression level of amyloid-beta and phosphorylated tau proteins in the hippocampus were figured out. Accordingly, VAR higher dose was selected to contemplate the possible underlying mechanisms. Intriguingly, VAR elevated the cyclic guanosine monophosphate level in the hippocampus and averted the repressed proteasome activity by AlCl3/D-gal; hence, VAR might alleviate the burden of toxic protein aggregates in AD. In addition, a substantial reduction in the activating transcription factor 6-mediated endoplasmic reticulum stress was demonstrated with VAR treatment. Notably, VAR counteracted the AlCl3/D-gal-induced depletion of nuclear factor erythroid 2-related factor 2 level. Moreover, the anti-senescence activity of VAR was demonstrated via its ability to restore the balance of the redox circuit. The modulation of phosphatidylinositol-3-kinase/protein kinase B/p53 pathway and the reduction of nuclear factor kappa B level, the key regulator of senescence-associated secretory phenotype mediators release, with VAR treatment were also elucidated. Altogether, these findings insinuate the possible therapeutic benefits of VAR in AD management.

Evaluation of Dimercaptosuccinic Acid-Coated Iron Nanoparticles Immunotargeted to Amyloid Beta as MRI Contrast Agents for the Diagnosis of Alzheimer's Disease

Nanoparticle-based magnetic contrast agents have opened the potential for magnetic resonance imaging (MRI) to be used for early non-invasive diagnosis of Alzheimer's disease (AD). Accumulation of amyloid pathology in the brain has shown association with cognitive decline and tauopathy; hence, it is an effective biomarker for the early detection of AD. The aim of this study was to develop a biocompatible magnetic nanoparticle targeted to amyloid beta (Aβ) plaques to increase the sensitivity of T2-weighted MRI for imaging of amyloid pathology in AD. We presented novel iron core-iron oxide nanoparticles stabilized with a dimercaptosuccinic acid coating and functionalized with an anti-Aβ antibody. Nanoparticle biocompatibility and cellular internalization were evaluated in vitro in U-251 glioblastoma cells using cellular assays, proteomics, and transmission electron microscopy. Iron nanoparticles demonstrated no significant in vitro cytotoxicity, and electron microscopy results showed their movement through the endocytic cycle within the cell over a 24 h period. In addition, immunostaining and bio-layer interferometry confirmed the targeted nanoparticle's binding affinity to amyloid species. The iron nanoparticles demonstrated favourable MRI contrast enhancement; however, the addition of the antibody resulted in a reduction in the relaxivity of the particles. The present work shows promising preliminary results in the development of a targeted non-invasive method of early AD diagnosis using contrast-enhanced MRI.

Enhancing the stability, BBB permeability and neuroprotective activity of verbascoside in vitro using lipid nanocapsules in combination with menthol

Verbascoside (VER) shows promising neuroprotective activity. However, the instability and low permeability in crossing the blood-brain barrier (BBB) greatly hinder its application. In the present study, verbascoside was encapsulated into lipid nanocapsules (LNC) by reverse micelle (RM) to increase its stability. Besides, we used VER-RM-LNC combined with an envoy drug, menthol, to improve its BBB permeability and neuroprotective activity. VER-RM-LNC was prepared by the phase inversion temperature method, resulting in an encapsulation efficiency of nearly 85 %. The formulated VER-RM-LNC was stable for 6 months at 4 °C. VER encapsulated into LNC possessed enhanced stability and a reduced release profile. Menthol increased the cellular uptake and the permeability of VER-RM-LNC in the BBB model in vitro. In addition, the improved neuroprotective activity of VER through incubation with menthol and VER-RM-LNC was verified in the neurotoxic human brain microvascular endothelial cells model induced by Aβ_25-35.

Study of anti-fatigue activity of polysaccharide from fruiting bodies of Armillaria gallica

Fatigue is a common physiological response that is closely related to energy metabolism. Polysaccharides, as excellent dietary supplements, have been proven to have a variety of pharmacological activities. In this study, A 23.007 kDa polysaccharide from Armillaria gallica (AGP) was purified and performed structural characterization, including analysis of homogeneity, molecular weight and monosaccharide composition. Methylation analysis is used to analyze the glycosidic bond composition of AGP. The mouse model of acute fatigue was used to evaluate the anti-fatigue effect of AGP. AGP-treatment improved exercise endurance in mice and reduced fatigue symptoms caused by acute exercise. AGP regulated the levels of adenosine triphosphate, lactic acid, blood urea nitrogen and lactate dehydrogenase, muscle glycogen and liver glycogen of acute fatigue mice. AGP affected the composition of intestinal microbiota, the changes of some intestinal microorganisms are correlated with fatigue and oxidative stress indicators. Meanwhile, AGP reduced oxidative stress levels, increased antioxidant enzyme activity and regulated the AMP-dependent protein kinase/nuclear factor erythroid 2-related factor 2 signaling pathway. AGP exerted an anti-fatigue effect through modulation of oxidative stress, which is related to intestinal microbiota.

Scutellaria incarnata Vent. root extract and isolated phenylethanoid glycosides are neuroprotective against C2-ceramide toxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Neuronal death is a central process in neurodegenerative diseases and represents a therapeutic challenge for their prevention and treatment. Scutellaria incarnata Vent. roots are used traditionally in Colombia for central nervous system conditions including those affecting cognitive functions, but their chemistry and neuroprotective action remain to be explored to understand the scientific basis for their medicinal uses. In this study, S. incarnata roots are investigated to assess whether they have neuroprotective effects that could provide some explanation for their traditional use in neurodegenerative diseases.

AIM OF THE STUDY

To evaluate the neuroprotective effect of S. incarnata roots and its chemical constituents against C₂-ceramide-induced cell death in Cath.-a-differentiated (CAD) cells.

MATERIALS AND METHODS

S. incarnata root ethanol extract was fractionated and compounds were isolated by column chromatography; their structures were elucidated by nuclear magnetic resonance spectroscopy, mass spectrometry and infrared spectroscopy. The cytotoxic and neuroprotective effects against C₂-ceramide of S. incarnata root extract, fractions and isolated compounds were assessed in CAD cells.

RESULTS

S. incarnata root extract and its n-butanol fraction were not cytotoxic but showed neuroprotective effects against C₂-ceramide toxicity in CAD cells. The phenylethanoid glycosides incarnatoside (isolated for the first time) and stachysoside C (12.5, 25 and 50 μg/mL) from S. incarnata roots also protected CAD cells against C₂-ceramide without inducing cytotoxic effects.

CONCLUSION

The observed neuroprotective effects of S. incarnata root extract and isolated phenylethanoid glycosides in CAD cells provide an ethnopharmacological basis for the traditional use of this species in Colombia for central nervous system disorders.

Exploring the therapeutic efficacy of Chlorella pyrenoidosa peptides in ameliorating Alzheimer's disease

Alzheimer's disease (AD) is one of the neurodegenerative disorders, the hallmarks of which include deposits of extracellular beta-amyloid (Aβ) as well as intracellular tau neurofibrillary tangles (NFTs) tangles. With disease progression, neuronal apoptosis combined with cerebral atrophy occurs, leading to cognitive impairment and long-term memory loss. Recently, Chlorella species have been identified as a functional food and are being explored for the prevention of various diseases widely studied to prevent or treat many neurodegenerative diseases. Hence, we for the first time investigated the neuroprotective effects of Chlorella pyrenoidosa short-chain peptides (CPPs) i.e. <1 kDa, 1-3 kDa, 3-10 kDa, and >10 kDa on the in vitro and in vivo neuronal injury models. Our in vitro results showed that CPP with a molecular weight of 1-3 kDa and 3-10 kDa could elevate the survival rate of Aβ_1-42 or l-Glutamic acid-injured N2A cells. These treatments also inhibited Aβ and tau NFTs in N2A cells and prevented progressive neuronal cellular damage by suppressing inflammatory cytokines such as PGE2, iNOS, IL-6, TNF-α, COX-2, IL-1β, TGF-β1, and NF-κB. Further, our in vivo Aβ_1-42-induced AD mice model demonstrated that 1-3 kDa or 3-10 kDa CPP could improve spatial cognition and learning memory. We also observed a decreased cell loss ratio in CA1-CA3 hippocampal regions. Taken together, our findings imply that CPPs may exert their anti-AD impact through anti-inflammatory, and anti-amyloid activities via reducing APP and tau NFT.

Alpinetin inhibits neuroinflammation and neuronal apoptosis via targeting the JAK2/STAT3 signaling pathway in spinal cord injury

BACKGROUND

A growing body of research shows that drug monomers from traditional Chinese herbal medicines have antineuroinflammatory and neuroprotective effects that can significantly improve the recovery of motor function after spinal cord injury (SCI). Here, we explore the role and molecular mechanisms of Alpinetin on activating microglia-mediated neuroinflammation and neuronal apoptosis after SCI.

METHODS

Stimulation of microglia with lipopolysaccharide (LPS) to simulate neuroinflammation models in vitro, the effect of Alpinetin on the release of pro-inflammatory mediators in LPS-induced microglia and its mechanism were detected. In addition, a co-culture system of microglia and neuronal cells was constructed to assess the effect of Alpinetin on activating microglia-mediated neuronal apoptosis. Finally, rat spinal cord injury models were used to study the effects on inflammation, neuronal apoptosis, axonal regeneration, and motor function recovery in Alpinetin.

RESULTS

Alpinetin inhibits microglia-mediated neuroinflammation and activity of the JAK2/STAT3 pathway. Alpinetin can also reverse activated microglia-mediated reactive oxygen species (ROS) production and decrease of mitochondrial membrane potential (MMP) in PC12 neuronal cells. In addition, in vivo Alpinetin significantly inhibits the inflammatory response and neuronal apoptosis, improves axonal regeneration, and recovery of motor function.

CONCLUSION

Alpinetin can be used to treat neurodegenerative diseases and is a novel drug candidate for the treatment of microglia-mediated neuroinflammation.

Bioactive Compounds of Verbascum sinuatum L.: Health Benefits and Potential as New Ingredients for Industrial Applications

Verbascum sinuatum (V. sinuatum) is a plant belonging to the Scrophulariaceae family that has been used as an ingredient in traditional medicine infusions for the treatment of many diseases. The aerial part of this plant is a source of bioactive compounds, especially polyphenols and iridoids. Moreover, antioxidant activity studies have shown that V. sinuatum phenolic and flavonoid composition is higher than those in other plants of the same genus. V. sinuatum bioactive compound composition could vary according to the harvesting location, growing conditions of the plants, sample preparation methods, type and concentration of the extraction solvent, and the extraction methods. The obtention of these compounds can be achieved by different extraction techniques, most commonly, maceration, heat assisted extraction, and infusion. Nevertheless, since conventional extraction techniques have several drawbacks such as long times of extraction or use of large amounts of solvents, the use of green extraction techniques is suggested, without affecting the efficiency of the extraction. Moreover, V. sinuatum bioactive compounds have several biological activities, such as antioxidant, anticancer, cardiovascular, antimicrobial, antidiabetic, and neuroprotective activities, that may be increased by encapsulation. Since the bioactive compounds extracted from V. sinuatum present good potential as functional food ingredients and in the development of drugs or cosmetics, this review gives an approach of the possible incorporation of these compounds in the food and pharmacological industries.

Bazi Bushen capsule attenuates cognitive deficits by inhibiting microglia activation and cellular senescence

CONTEXT

Bazi Bushen capsule (BZBS) has anti-ageing properties and is effective in enhancing memory.

OBJECTIVE

To find evidence supporting the mechanisms and biomarkers by which BZBS functions.

MATERIALS AND METHODS

Male C57BL/6J mice were randomly divided into five groups: normal, ageing, β-nicotinamide mononucleotide capsule (NMN), BZBS low-dose (LD-BZ) and BZBS high-dose (HD-BZ). The last four groups were subcutaneously injected with d-galactose (d-gal, 100 mg/kg/d) to induce the ageing process. At the same time, the LD-BZ, HD-BZ and NMN groups were intragastrically injected with BZBS (1 and 2 g/kg/d) and NMN (100 mg/kg/d) for treatment, respectively. After 60 days, the changes in overall ageing status, brain neuron morphology, expression of p16^INK4a, proliferating cell nuclear antigen (PCNA), ionized calcium-binding adapter molecule 1 (Iba1), postsynaptic density protein 95 (PSD95), CD11b, Arg1, CD206, Trem2, Ym1 and Fizz1, and the senescence-associated secretory phenotype (SASP) factors were observed.

RESULTS

Compared with the mice in the ageing group, the HD-BZ mice exhibited obvious improvements in strength, endurance, motor coordination, cognitive function and neuron injury. The results showed a decrease in p16^INK4a, Iba1 and the upregulation of PCNA, PSD95 among brain proteins. The brain mRNA exhibited downregulation of Iba1 (p < 0.001), CD11b (p < 0.001), and upregulation of Arg1 (p < 0.01), CD206 (p < 0.05), Trem2 (p < 0.001), Ym1 (p < 0.01), Fizz1 (p < 0.05) and PSD95 (p < 0.01), as well as improvement of SASP factors.

CONCLUSIONS

BZBS improves cognitive deficits via inhibition of cellular senescence and microglia activation. This study provides experimental evidence for the wide application of BZBS in clinical practice for cognitive deficits.

The Structural Characterization and Immunomodulatory Activity of Polysaccharides from Pleurotus abieticola Fruiting Bodies

Polysaccharides obtained from mushrooms have been reported to possess immunomodulatory properties. In this study, a water-soluble polysaccharide was purified from the fruiting bodies of Pleurotus abieticola, entitled PAPS1. After its composition and structural analysis, the immunomodulatory activity was investigated in immunosuppressed mice induced by cyclophosphamide (CTX) at a dosage of 70 mg/kg by intraperitoneal injection for 7 days. After 28 days of intragastric administration, PAPS1 alleviated cyclophosphamide (CTX)-induced histopathological damage and increased the expressions of splenic CD4, CD8, CD56 and IgM in the serums of immunosuppressed mice. PAPS1 suppressed the oxidative stress indicated by preventing the increases in ROS and MDA levels. According to the intestinal microflora analysis, PAPS1 regulated 11 bacteria at the gene level, including Helicobacter and Paraprevotella, which are related to immunity and oxidative capacity. Compared with CTX-treated mice, significant increases in immune-related cytokines, such as interleukin (IL)-2, IL-6 and IL-12 in the serums of mice treated with PAPS1, were observed. Finally, PAPS1 can strongly increase the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream proteins. In conclusion, PAPS1-boosted immunity may be related to its suppression on oxidative stress via enhancing the activity of Nrf2 signaling. Thus, PAPS1 can be investigated as a candidate for immunomodulatory therapy.

Anti-Colorectal Cancer Effects of Inonotus hispidus (Bull.: Fr.) P. Karst. Spore Powder through Regulation of Gut Microbiota-Mediated JAK/STAT Signaling

Inonotus hispidus (Bull.: Fr.) P. Karst. spore powder (IHS) contains polyphenols and triterpenoids with pharmacological effects. Here, we analyzed its composition, and we investigated the effects of IHS on colorectal cancer (CRC) in B6/JGpt-Apc^em1Cin(min)/Gpt (Apc^Min/+) mice and its potential mechanisms by analyzing gut microbiota and serum metabolomics. The enzyme-linked immunosorbent assays and Western blotting were used to confirm the changes in the cytokine and protein levels associated with IHS administration. The IHS affected the abundance of gut microbiota and the level of L-arginine (L-Arg). Furthermore, the IHS influenced T cells in Apc^Min/+ mice by increasing the interleukin (IL)-2 and decreasing the IL-5, -6, and -10 levels, thus suppressing tumor development. Overall, IHS showed anti-CRC properties in Apc^Min/+ mice by affecting the gut microbiota and serum metabolites, which in turn affected the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling, and regulated the abundance of CD8⁺ T cells. These results provide experimental support for the potential future treatment of CRC with IHS.

The involvement of gut microbiota in the anti-tumor effect of carnosic acid via IL-17 suppression in colorectal cancer

Colorectal cancer (CRC) is a malignant tumor that threatens human health worldwide. Disturbance of the gut microbiota caused by various external factors is one of the leading causes. Carnosic acid (CA) is a phenolic diterpene compound, mainly isolated from rosemary plants, with anti-inflammatory and anti-tumor properties. In this study, we aimed to investigate the role of CA in CRC development and its underlying mechanisms in B6/JGpt-Apc^em1Cin(min)/Gpt (Apc^Min/+) mice based on the analysis of gut microbiota, serum metabolomics, and tumor proteomics. Enzyme-linked immunosorbent assay (ELISA) and Western blot were performed to confirm the changes in cytokine and protein levels related to inflammation after CA administration. CA regulated the abundance of the gut microbiota, which further caused changes in the production of dl-lactic acid. CA suppressed the inflammatory response by reducing the levels of IL-1β, -6, and -17A. Overall, CA showed anti-CRC properties via modulation of gut microbiota and serum metabolites through NF-κB/STAT3 signaling to inhibit IL-17 expression in Apc^Min/+ mice. These results provide experimental evidence for the future treatment of CRC with CA.

Proteomics-based investigation of cerebrovascular molecular mechanisms in cerebral amyloid angiopathy by the FFPE-LMD-PCT-SWATH method

Background

Cerebral amyloid angiopathy (CAA) occurs in 80% of patients with Alzheimer’s disease (AD) and is mainly caused by the abnormal deposition of Aβ in the walls of cerebral blood vessels. Cerebrovascular molecular mechanisms in CAA were investigated by using comprehensive and accurate quantitative proteomics.

Methods

Concerning the molecular mechanisms specific to CAA, formalin-fixed paraffin-embedded (FFPE) sections were prepared from patients having AD neuropathologic change (ADNC) with severe cortical Aβ vascular deposition (ADNC +/CAA +), and from patients having ADNC without vascular deposition of Aβ (ADNC +/CAA −; so called, AD). Cerebral cortical vessels were isolated from FFPE sections using laser microdissection (LMD), processed by pressure cycling technology (PCT), and applied to SWATH (sequential window acquisition of all theoretical fragment ion spectra) proteomics.

Results

The protein expression levels of 17 proteins in ADNC +/CAA +/H donors (ADNC +/CAA + donors with highly abundant Aβ in capillaries) were significantly different from those in ADNC +/CAA − and ADNC −/CAA − donors. Furthermore, we identified 56 proteins showing more than a 1.5-fold difference in average expression levels between ADNC +/CAA + and ADNC −/CAA − donors, and were significantly correlated with the levels of Aβ or Collagen alpha-2(VI) chain (COL6A2) (CAA markers) in 11 donors (6 ADNC +/CAA + and 5 ADNC −/CAA −). Over 70% of the 56 proteins showed ADNC +/CAA + specific changes in protein expression. The comparative analysis with brain parenchyma showed that more than 90% of the 56 proteins were vascular-specific pathological changes. A literature-based pathway analysis showed that 42 proteins are associated with fibrosis, oxidative stress and apoptosis. This included the increased expression of Heat shock protein HSP 90-alpha, CD44 antigen and Carbonic anhydrase 1 which are inhibited by potential drugs against CAA.

Conclusions

The combination of LMD-based isolation of vessels from FFPE sections, PCT-assisted sample processing and SWATH analysis (FFPE-LMD-PCT-SWATH method) revealed for the first time the changes in the expression of many proteins that are involved in fibrosis, ROS production and cell death in ADNC +/CAA +  (CAA patients) vessels. The findings reported herein would be useful for developing a better understanding of the pathology of CAA and for promoting the discovery and development of drugs and biomarkers for CAA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00351-x.

Neuroprotective Effects of Oligosaccharides in Rehmanniae Radix on Transgenic Caenorhabditis elegans Models for Alzheimer’s Disease

Rehmanniae Radix (RR, the dried tuberous roots of Rehmannia glutinosa (Gaertn.) DC.) is an important traditional Chinese medicine distributed in Henan, Hebei, Inner Mongolia, and Northeast in China. RR is frequently used to treat diabetes mellitus, cardiovascular disease, osteoporosis and aging-related diseases in a class of prescriptions. The oligosaccharides and catalpol in RR have been confirmed to have neuroprotective effects. However, there are few studies on the anti-Alzheimer’s disease (AD) effect of oligosaccharides in Rehmanniae Radix (ORR). The chemical components and pharmacological effects of dried Rehmannia Radix (DRR) and prepared Rehmannia Radix (PRR) are different because of the different processing methods. ORR has neuroprotective potential, such as improving learning and memory in rats. Therefore, this study aimed to prove the importance of oligosaccharides in DRR (ODRR) and PRR (OPRR) for AD based on the Caenorhabditis elegans (C. elegans) model and the different roles of ODRR and OPRR in the treatment of AD. In this study, we used paralysis assays, lifespan and stress resistance assays, bacterial growth curve, developmental and behavioral parameters, and ability of learning and memory to explore the effects of ODRR and OPRR on anti-AD and anti-aging. Furthermore, the accumulation of reactive oxygen species (ROS); deposition of Aβ; and expression of amy-1, sir-2.1, daf-16, sod-3, skn-1, and hsp-16.2 were analyzed to confirm the efficacy of ODRR and OPRR. OPRR was more effective than ODRR in delaying the paralysis, improving learning ability, and prolonging the lifespan of C. elegans. Further mechanism studies showed that the accumulation of ROS, aggregation, and toxicity of Aβ were reduced, suggesting that ORR alleviated Aβ-induced toxicity, in part, through antioxidant activity and Aβ aggregation inhibiting. The expression of amy-1 was downregulated, and sir-2.1, daf-16, sod-3, and hsp-16.2 were upregulated. Thus, ORR could have a possible therapeutic effect on AD by modulating the expression of amy-1, sir-2.1, daf-16, sod-3, and hsp-16.2. Furthermore, ORR promoted the nuclear localization of daf-16 and further increased the expression of sod-3 and hsp-16.2, which significantly contributed to inhibiting the Aβ toxicity and enhancing oxidative stress resistance. In summary, the study provided a new idea for the development of ORR.

The Neuroprotection of Verbascoside in Alzheimer’s Disease Mediated through Mitigation of Neuroinflammation via Blocking NF-κB-p65 Signaling

Verbascoside (VB) is a phenylethanoid glycoside extracted from the herbaceous plant Verbascum sinuatum and plays a neuroprotective role in Alzheimer’s disease (AD). The goal of this study was to explore the neuroprotective mechanism of VB. Based on the proteomics analysis, immunohistochemistry, immunofluorescence, Western blot, and ELISA were utilized to explore the neuroprotective mechanism of VB in context of neuroinflammation in APP/PS1 mice, LPS-induced BV2 cells, and/or Aβ_1-42-stimulated N2a cells. Proteomic analysis demonstrated that the neuroprotection of VB correlated closely to its anti-inflammatory effect. VB significantly blocked microglia and astrocyte against activation in brains of APP/PS1 mice, suppressed the generation of IL-1β as well as IL-6, and boosted that of IL-4, IL-10 and TGF-β in vivo, which were analogous to results acquired in vitro. Furthermore, VB effectively restrained the phosphorylation of IKKα+β, IκBα, and NF-κB-p65 in APP/PS1 mice; LPS-induced BV2 cells, and Aβ_1-42-stimulated N2a cells and lowered the tendency of NF-κB-p65 translocation towards nucleus in vitro. These results demonstrate that the neuroprotective effect of VB correlates to the modulation of neuroinflammation via NF-κB-p65 pathway, making VB as a hopeful candidate drug for the prevention and treatment of AD.

Forsythoside A Mitigates Alzheimer's-like Pathology by Inhibiting Ferroptosis-mediated Neuroinflammation via Nrf2/GPX4 Axis Activation

Ferroptosis and neuroinflammation play crucial roles in Alzheimer's disease (AD) pathophysiology. Forsythoside A (FA), the main constituent of Forsythia suspensa (Thunb.) Vahl., possesses anti-inflammatory, antibacterial, antioxidant, and neuroprotective properties. The present study aimed to investigate the potential role of FA in AD neuropathology using male APP/PS1 double transgenic AD mice, Aβ_1-42-exposed N2a cells, erastin-stimulated HT22 cells, and LPS-induced BV2 cells. FA treatment significantly improved mitochondrial function and inhibited lipid peroxidation in Aβ_1-42-exposed N2a cells. In LPS-stimulated BV2 cells, FA treatment decreased the formation of the pro-inflammatory factors IL-6, IL-1β, and NO. In male APP/PS1 mice, FA treatment ameliorated memory and cognitive impairments and suppressed Aβ deposition and p-tau levels in the brain. Analyses using proteomics, immunohistochemistry, ELISA, and western blot revealed that FA treatment significantly augmented dopaminergic signaling, inhibited iron deposition and lipid peroxidation, prevented the activation of IKK/IκB/NF-κB signaling, reduced the secretion of pro-inflammatory factors, and promoted the production of anti-inflammatory factors in the brain. FA treatment exerted anti-ferroptosis and anti-neuroinflammatory effects in erastin-stimulated HT22 cells, and the Nrf2/GPX4 axis played a key role in these effects. Collectively, these results demonstrate the protective effects of FA and highlight its therapeutic potential as a drug component for AD treatment.

Nanotechnology-Based Drug Delivery Strategies to Repair the Mitochondrial Function in Neuroinflammatory and Neurodegenerative Diseases

Mitochondria are vital organelles in eukaryotic cells that control diverse physiological processes related to energy production, calcium homeostasis, the generation of reactive oxygen species, and cell death. Several studies have demonstrated that structural and functional mitochondrial disturbances are involved in the development of different neuroinflammatory (NI) and neurodegenerative (ND) diseases (NI&NDDs) such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Remarkably, counteracting mitochondrial impairment by genetic or pharmacologic treatment ameliorates neurodegeneration and clinical disability in animal models of these diseases. Therefore, the development of nanosystems enabling the sustained and selective delivery of mitochondria-targeted drugs is a novel and effective strategy to tackle NI&NDDs. In this review, we outline the impact of mitochondrial dysfunction associated with unbalanced mitochondrial dynamics, altered mitophagy, oxidative stress, energy deficit, and proteinopathies in NI&NDDs. In addition, we review different strategies for selective mitochondria-specific ligand targeting and discuss novel nanomaterials, nanozymes, and drug-loaded nanosystems developed to repair mitochondrial function and their therapeutic benefits protecting against oxidative stress, restoring cell energy production, preventing cell death, inhibiting protein aggregates, and improving motor and cognitive disability in cellular and animal models of different NI&NDDs.

Glypican 4 Regulates Aβ Internalization in Neural Stem Cells Partly via Low-Density Lipoprotein Receptor-Related Protein 1

Neural stem cell (NSC) damage has been reported in patients with Alzheimer’s disease. Intracellular Aβ plays a vital role in NSC damage. Heparan sulfate proteoglycans are potent mediators of Aβ enrichment in the brain. We hypothesized the heparan sulfate proteoglycan glypican 4 (Gpc4) regulates Aβ internalization by NSCs. We evaluated Gpc4 expression in NSCs from P0–P2 generations using immunofluorescence. Adenovirus and lentivirus were used to regulate Gpc4 expression in NSCs and APP/PS1 mice, respectively. Co-immunoprecipitation was used to determine the relationship between Gpc4, Aβ, and low-density lipoprotein receptor-related protein 1 (LRP1). Intracellular Aβ concentrations were detected using enzyme-linked immunosorbent assay and immunofluorescence. The role of Gpc4/LRP1 on toxic/physical Aβ-induced effects was evaluated using the JC-1 kit, terminal deoxynucleotidyl transferase dUPT nick end labeling, and western blotting. Gpc4 was stably expressed in NSCs, neurons, and astrocytes. Gpc4 was upregulated by Aβ in NSCs and regulated Aβ internalization. Gpc4 attenuation reduced Aβ uptake; Gpc4 overexpression increased Aβ uptake. Gpc4 regulated Aβ internalization through LRP1 and contributed to Aβ internalization and toxic/physical concentrations of Aβ-induced mitochondrial membrane potential and cell apoptosis, partly via LRP1. Therefore, Gpc4 is a key regulator of Aβ enrichment in NSCs. Inhibiting Gpc4 rescued the Aβ-induced toxic effect and attenuated the nontoxic Aβ enrichment into intracellular toxic concentrations. Gpc4 contributed to Aβ internalization and toxic/physical concentrations of Aβ-induced mitochondrial membrane potential damage and cell apoptosis, partly via LRP1. These findings suggest a potential role of Gpc4 in treating Alzheimer’s disease at an early stage, by targeting NSCs.