Signaling Pathways Involved in the Neuroprotective Effect of Osthole: Evidence and Mechanisms

The LDL Receptor-Related Protein 1: Mechanisms and roles in promoting Aβ efflux transporter in Alzheimer's disease

The LDL Receptor-Related Protein 1(LRP1), a member of the Low-density Lipoprotein (LDL) receptor family, is a multifunctional cellular transporter and signaling receptor, this includes regulation of lipid metabolism, cell migration and signaling. Abnormal accumulation of amyloid beta (Aβ) in the brain is thought to be the main pathological change in Alzheimer's disease. By binding to a variety of ligands, LRP1 is involved in the internalization and degradation of Aβ, thereby affecting the course of Alzheimer's disease (AD). Here, we discuss the main mechanisms by which LRP1 mediates Aβ degradation and clearance and several current therapeutic approaches targeting LRP1. Finally, we concluded that modulating the expression level of LRP1 is an effective way to attenuate Aβ deposition and ameliorate AD. Abbreviations: LRP1, LDL Receptor-Related Protein 1;LDL, Low Density Lipoprotein; Aβ, amyloid beta; AD, Alzheimer's disease; APP, amyloid precursor protein; ApoE, apolipoprotein E; TGF, growth factor; MMP, matrix metalloproteinase;TAT, thrombin-antithrombin complex; BBB, blood-brain barrier; MMP-9,cyclophilin A (CypA)-matrix metalloproteinase-9; VMC, Vascular Mural Cell; IDE,insulin degrading enzyme; EVs, extracellular vesicles; sLRP1,shed LRP1; BDNF, brain-derived neurotrophin; IGF-1,insulin-like growth factor 1; NGF, nerve growth factor; MAPK,mitogen-activated protein kinase; ERK1/2,exogenous signal-regulated kinase1/2;JNK, c-Jun amino-terminal kinase; TLR4, toll-like receptor 4; NF-κB,nuclear factor-κB; GCAP,guanylate cyclase-activating protein; KD, ketogenic diet;KB, ketone body; BLECs,Brain-like endothelial cell; BYHWD, Buyang Huanwu decoction; LGZG, Linguizhugan decoction;P- gp, P-glycoprotein;PPARγ, Peroxisome proliferator-activated receptor γ;SP16,SERPIN peptide 16; Asx, Astaxanthin; Bex, Bexarotene.

Osthole ameliorates wear particle-induced osteogenic impairment by mitigating endoplasmic reticulum stress via PERK signaling cascade

BACKGROUND

Periprosthetic osteolysis and subsequent aseptic loosening are the leading causes of failure following total joint arthroplasty. Osteogenic impairment induced by wear particles is regarded as a crucial contributing factor in the development of osteolysis, with endoplasmic reticulum (ER) stress identified as a key underlying mechanism. Therefore, identifying potential therapeutic targets and agents that can regulate ER stress adaption in osteoblasts is necessary for arresting aseptic loosening. Osthole (OST), a natural coumarin derivative, has demonstrated promising osteogenic properties and the ability to modulate ER stress adaption in various diseases. However, the impact of OST on ER stress-mediated osteogenic impairment caused by wear particles remains unclear.

METHODS

TiAl6V4 particles (TiPs) were sourced from the prosthesis of patients who underwent revision hip arthroplasty due to aseptic loosening. A mouse calvarial osteolysis model was utilized to explore the effects of OST on TiPs-induced osteogenic impairment in vivo. Primary mouse osteoblasts were employed to investigate the impact of OST on ER stress-mediated osteoblast apoptosis and osteogenic inhibition induced by TiPs in vitro. The mechanisms underlying OST-modulated alleviation of ER stress induced by TiPs were elucidated through Molecular docking, immunochemistry, PCR, and Western blot analysis.

RESULTS

In this study, we found that OST treatment effectively mitigated TiAl6V4 particles (TiPs)-induced osteolysis by enhancing osteogenesis in a mouse calvarial model. Furthermore, we observed that OST could attenuate ER stress-mediated apoptosis and osteogenic reduction in osteoblasts exposed to TiPs in vitro and in vivo. Mechanistically, we demonstrated that OST exerts bone-sparing effects on stressed osteoblasts upon TiPs exposure by specifically suppressing the ER stress-dependent PERK signaling cascade.

CONCLUSION

Osthole ameliorates wear particle-induced osteogenic impairment by mitigating endoplasmic reticulum stress via PERK signaling cascade. These findings suggest that OST may serve as a potential therapeutic agent for combating wear particle-induced osteogenic impairment, offering a novel alternative strategy for managing aseptic prosthesis loosening.

A review of the ethnomedicinal, phytochemical, and pharmacological properties of the Ferulago genus based on Structure-Activity Relationship (SAR) of coumarins

BACKGROUND

The Ferluago W.D.J. Koch genus includes 48 accepted perennial herbs that are distributed in the Mediterranean region, Southeast Europe, Central and Middle East of Asia. These plants are widely used in folk and conventional medicine due to their biological benefits such as anti-microbial, anti-inflammatory, anti-cancer, and immunomodulatory properties. Conducting a comprehensive review based on the structure activity relationships (SARs) of the coumarins, which has not been previously documented, can lead to a better insight into the genus Ferulago and its beneficial therapeutic activities.

METHODS

This review covers literature from 1969 to 2023, were collected from various scientific electronic databases to review phytochemical, pharmacological, and ethnopharmacological data of Ferulago species, as well as latest information on the SAR of reported coumarins from this genus.

RESULTS

Phytochemical studies showed that the biological actions of this genus are mediated by the reported specialized metabolites, such as coumarins and flavonoids. Simple coumarins, prenylated coumarins, furanocoumarins, and pyranocoumarins are the largest subclasses of coumarins found in diverse Ferulago species, which have discussed the biological effects of them with a focus on the Structure-Activity Relationship (SAR). For example, prenylated coumarins have shown potential leishmanicidal and anti-neuropsychiatric effects when substituted with a prenyl group at the 7-hydroxy, as well as the C6 and C8 positions in their scaffold. Similarly, furanocoumarins exhibit varied biological activities such as anti-inflammatory, anti-proliferative, and anti-convulsant effects. Modifying substitutions at the C5 and C6 positions in furanocoumarins can enhance these activities.

CONCLUSION

This study conducted a comprehensive review of all available information on the phytochemical and pharmacological characteristics of Ferulago species. Given the high occurrence of coumarins in this genus, which exhibit potential anti-Alzheimer and anti-microbial properties, it presents promising new therapeutic avenues for addressing these common issues. Further investigation is needed to understand the molecular-level mechanisms of action and to explore their clinical applications.

Exploring the therapeutic implications of natural compounds modulating apoptosis in vascular dementia

Vascular dementia (VaD) is a prevalent form of dementia stemming from cerebrovascular disease, manifesting in memory impairment and executive dysfunction, thereby imposing a substantial societal burden. Unfortunately, no drugs have been approved for the treatment of VaD due to its intricate pathogenesis, and the development of innovative and efficacious medications is urgently needed. Apoptosis, a programmed cell death process crucial for eliminating damaged or unwanted cells within an organism, assumes pivotal roles in embryonic development and tissue homeostasis maintenance. An increasing body of evidence indicates that apoptosis may significantly influence the onset and progression of VaD, and numerous natural compounds have demonstrated significant therapeutic potential. Here, we discuss the molecular mechanisms underlying apoptosis and its correlation with VaD. We also provide a crucial reference for developing innovative pharmaceuticals by systematically reviewing the latest research progress concerning the neuroprotective effects of natural compounds on VaD by regulating apoptosis. Further high-quality clinical studies are imperative to firmly ascertain these natural compounds' clinical efficacy and safety profiles in the treatment of VaD.

Astragaloside IV alleviates heatstroke brain injury and neuroinflammation in male mice by regulating microglial polarization via the PI3K/Akt signaling pathway

Heatstroke is a condition caused by overheating of the body that leads to severe central nervous system dysfunction. Although there have been numerous studies on the pathological process of heatstroke, effective treatment methods are lacking. Astragaloside IV can protect the brain from inflammation and brain damage in various inflammation-related diseases, but it has not yet been used clinically for the treatment of heatstroke. Therefore, the aim of this study was to explore the neuroprotective effect of Astragaloside IV on heatstroke-induced central nervous system damage and its mechanism. Brain injury model under heatstroke was established using artificial climate simulation cabin. By scoring neurological deficits, performing histological and immunofluorescence staining of microglia, and detecting cytokine levels, we determined that Astragaloside IV alleviated brain injury and neuroinflammation. To further explore the potential molecular mechanism, RNA sequencing was performed to investigate the differences in the brain. The results revealed that the PI3K/AKT pathway is involved. In vitro experiments further confirmed that Astragaloside IV can abrogate the phenotypic changes in microglia induced by heatstroke. Moreover, Astragaloside IV promotes the polarization of M2 microglia by activating the PI3K/AKT pathway. In summary, these results indicate that Astragaloside IV alleviates neuroinflammation and brain injury induced by heatstroke through the PI3K/AKT pathway. Astragaloside IV is a commonly used therapeutic agent in the clinic, but its use in the treatment of heatstroke-induced brain injury has not been explored. This study reveals that Astragaloside IV may be a new therapeutic agent for the treatment of heatstroke-induced brain injury.

A Review of the Ethnobotanical Use, Chemistry and Pharmacological Activities of Constituents Derived from the Plant Genus Geijera (Rutaceae)

Geijera Schott is a plant genus of the Rutaceae Juss. (rue and citrus) family, comprising six species which are all native to Oceania. Of the plants belonging to this genus, the most significant species that has a customary use is Geijera parviflora, which was used by Indigenous Australians, primarily as a pain reliever. Herein, a comprehensive review of the literature published on the genus Geijera from 1930 to 2023 was conducted. This is the first review for this plant genus, and it highlights the chemical constituents reported to date, together with the range of pharmacological properties described from the various species and different parts of the plant. These properties include anti-inflammatory, anti-microbial, anti-parasitic, insect repellent, analgesic, neuroactive, and anti-cancer activities. Finally, a reflection on some of the important areas for future focused studies of this plant genus is provided.

Silva H, P. de Carvalho R, Ventura ALM, Calaza KC, Silveira MS, Kubrusly RCC, de Melo Reis RA. The Healthy and Diseased Retina Seen through Neuron-Glia Interactions

The retina is the sensory tissue responsible for the first stages of visual processing, with a conserved anatomy and functional architecture among vertebrates. To date, retinal eye diseases, such as diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, glaucoma, and others, affect nearly 170 million people worldwide, resulting in vision loss and blindness. To tackle retinal disorders, the developing retina has been explored as a versatile model to study intercellular signaling, as it presents a broad neurochemical repertoire that has been approached in the last decades in terms of signaling and diseases. Retina, dissociated and arranged as typical cultures, as mixed or neuron- and glia-enriched, and/or organized as neurospheres and/or as organoids, are valuable to understand both neuronal and glial compartments, which have contributed to revealing roles and mechanisms between transmitter systems as well as antioxidants, trophic factors, and extracellular matrix proteins. Overall, contributions in understanding neurogenesis, tissue development, differentiation, connectivity, plasticity, and cell death are widely described. A complete access to the genome of several vertebrates, as well as the recent transcriptome at the single cell level at different stages of development, also anticipates future advances in providing cues to target blinding diseases or retinal dysfunctions.

Neuroinflammation and Neurodegenerative Diseases: How Much Do We Still Not Know?

The term "neuroinflammation" defines the typical inflammatory response of the brain closely related to the onset of many neurodegenerative diseases (NDs). Neuroinflammation is well known, but its mechanisms and pathways are not entirely comprehended. Some progresses have been achieved through many efforts and research. Consequently, new cellular and molecular mechanisms, diverse and conventional, are emerging. In listing some of those that will be the subject of our description and discussion, essential are the important roles of peripheral and infiltrated monocytes and clonotypic cells, alterations in the gut-brain axis, dysregulation of the apelinergic system, alterations in the endothelial glycocalyx of the endothelial component of neuronal vascular units, variations in expression of some genes and levels of the encoding molecules by the action of microRNAs (miRNAs), or other epigenetic factors and distinctive transcriptional factors, as well as the role of autophagy, ferroptosis, sex differences, and modifications in the circadian cycle. Such mechanisms can add significantly to understanding the complex etiological puzzle of neuroinflammation and ND. In addition, they could represent biomarkers and targets of ND, which is increasing in the elderly.