IGF-1 receptor is involved in the regulatory effects of icariin and icaritin in astrocytes under basal conditions and after an inflammatory challenge

Natural drug delivery systems for the treatment of neurodegenerative diseases

Today, herbal drugs are prominent in the pharmaceutical industry due to their well-known therapeutic and side effects. Plant-based compounds often face limitations such as poor solubility, low bioavailability, and instability in physiological environments, restricting their therapeutic efficacy and delivery. Nanotechnology-based solutions, including nanoparticle formulations and advanced delivery systems like liposomes and transfersomes, address these issues by enhancing solubility, stability, bioavailability, and targeted delivery, thereby optimizing the therapeutic potential of phytoactive compounds. Neuroinflammation can be a cause of neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, or amyotrophic lateral sclerosis. Consequently, there is a need for the optimal delivery of a pharmacological anti-inflammatory agents to the CNS. Thus, the non-invasive administration of a stable compound at a therapeutic concentration is needed to assure molecule crossing through the blood-brain barrier. Natural resources have more structural diversity and novelty than synthetic compounds, e.g. plant-derived drug products have higher molecular weights, incorporate more oxygen atoms, and are more complex. As a result, plant-derived products have unique features which can be used to effectively modulate neuroinflammation. Therefore, this review aims to identify herbal molecules capable of targeting neuroinflammation and present novel strategies for their efficient delivery.

Icariin promotes functional recovery in rats after spinal cord injury by inhibiting YAP and regulating PPM1B ubiquitination to inhibiting the activation of reactive astrocytes

Objective

The limited ability to regenerate axons after spinal cord injury (SCI) is influenced by factors such as astrocyte activation, reactive proliferation, and glial scar formation. The TGF-β/Smad (transforming growth factor-β/mothers against decapentaplegic homolog) pathway, associated with astrocytic scarring, plays a crucial role in recovery post-injury. This study aims to investigate how icariin (ICA) interacts with reactive astrocytes in the treatment of spinal cord injury.

Methods

A rat SCI model was constructed, and the recovery of motor function was observed after treatment with ICA.HE staining, LFB staining, immunofluorescence staining, and Western blotting were employed to assess ICA's ability to inhibit astrocyte proliferation in rats following spinal cord injury by modulating YAP, as well as to evaluate the reparative effects of ICA on the injured spinal cord tissue. Primary astrocytes were isolated and cultured. Immunoprecipitation-Western Blot (IP-WB) ubiquitination and cytoplasm-nuclear separation were employed to assess PPM1B ubiquitination and nuclear translocation.

Results

The CatWalk XT gait analysis, BBB (Basso, Beattie, and Bresnahan) score, electrophysiological measurements, HE staining, and LFB staining collectively demonstrated that ICA promotes motor function and tissue recovery following spinal cord injury in rats. Immunofluorescence staining and Western Blot analyses revealed that ICA inhibits astrocyte proliferation in rats post-spinal cord injury by suppressing YAP activity. Furthermore, the activation of YAP by XMU-MP-1 was shown to compromise the efficacy of ICA in these rats after spinal cord injury. Additional immunofluorescence staining and Western Blot experiments confirmed that ICA inhibits TGFβ1-induced astrocyte activation through the regulation of YAP. The knockdown of PPM1B (protein phosphatase, Mg2+/Mn2+-dependent 1B) in astrocytes was found to inhibit TGFβ signaling. Additionally, YAP was shown to regulate PPM1B ubiquitination and nuclear translocation through immunoprecipitation-Western blot analysis, along with the segregation of cytoplasm and nucleus.

Conclusion

Icariin promotes functional recovery in rats after spinal cord injury by inhibiting YAP and regulating PPM1B ubiquitination to inhibiting the activation of reactive astrocytes.

Small-molecule-based targeted therapy in liver cancer

Liver cancer is one of the most prevalent malignant tumors worldwide. According to the Barcelona Clinic Liver Cancer staging criteria, clinical guidelines provide tutorials to clinical management of liver cancer at their individual stages. However, most patients diagnosed with liver cancer are at advanced stage; therefore, many researchers conduct investigations on targeted therapy, aiming to improve the overall survival of these patients. To date, small-molecule-based targeted therapies are highly recommended (first line: sorafenib and lenvatinib; second line: regorafenib and cabozantinib) by current the clinical guidelines of the American Society of Clinical Oncology, European Society for Medical Oncology, and National Comprehensive Cancer Network. Herein, we summarize the small-molecule-based targeted therapies in liver cancer, including the approved and preclinical therapies as well as the therapies under clinical trials, and introduce their history of discovery, clinical trials, indications, and molecular mechanisms. For drug resistance, the revealed mechanisms of action and the combination therapies are also discussed. In fact, the known small-molecule-based therapies still have limited clinical benefits to liver cancer patients. Therefore, we analyze the current status and give our ideas for the urgent issues and future directions in this field, suggesting clues for novel techniques in liver cancer treatment.

Neuroprotective Effects of Bexarotene and Icariin in a Diabetic Rat Model

Objective Type 2 diabetes mellitus (T2DM), a chronic metabolic disorder affecting over 400 million people globally, is increasingly recognized for its detrimental impact on the central nervous system. T2DM is linked to neurodegenerative diseases like Alzheimer's and vascular dementia. This study investigates the neuroprotective effects of bexarotene and icariin in a T2DM rat model, focusing on brain-derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), and neurofilament-light chain (NfL) levels. Methods Before the study, rats underwent fasting blood glucose tests, lipid profile assessments, and general health evaluations, followed by a high-fat diet for two weeks and a single streptozotocin dose (35 mg/kg). Rats with fasting blood glucose levels ≥250 mg/dl were classified as diabetes mellitus (DM) and continued on the high-fat diet throughout the experiment. Forty-seven male Wistar Albino rats were divided into six groups: a healthy control group, a DM control group, a DM group treated with bexarotene, a DM group treated with icariin, and two DM groups treated with combinations of low and high doses of bexarotene and icariin. After the 45-day treatment, blood samples were collected under thiopental sodium anesthesia, with HbA1c (glycosylated hemoglobin) and hematological parameters analyzed within eight hours, and serum stored at -80°C for further analysis. The animals were then euthanized, and brain tissues were harvested, frozen, and stored at -80°C until further examination. Brain tissues were analyzed for BDNF, GFAP, and NfL levels using ELISA (enzyme-linked immunosorbent assay). For comparing multiple groups, the Kruskal-Wallis test was applied to nonparametric data, and one-way ANOVA was used for parametric data, followed by Bonferroni's post hoc test for pairwise comparisons. Statistical significance was determined with two-tailed tests at p < 0.05. Results Significant changes in GFAP levels were observed across groups (p < 0.001). The DM control group showed the highest GFAP levels, while treatment groups exhibited reductions. The DM control group also showed the highest BDNF levels, while treatment groups exhibited reductions. The DM control group showed the lowest NfL levels, while treatment groups exhibited increments. Conclusion This study highlights the neuroprotective potential of bexarotene and icariin in a diabetic rat model, evidenced by significant changes in GFAP levels. The lack of significant changes in BDNF and NfL suggests that longer study durations may be necessary to observe these effects. Future research should include extended study periods, larger sample sizes, varied dosages, and comprehensive behavioral assessments to better understand the therapeutic potential of these agents.

Icariin mitigates anxiety-like behaviors induced by hemorrhagic shock and resuscitation via inhibiting of astrocytic activation

BACKGROUND

Abnormal activation of astrocytes in the amygdala contributes to anxiety after hemorrhagic shock and resuscitation (HSR). Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB)-associated epigenetic reprogramming of astrocytic activation is crucial to anxiety. A bioactive monomer derived from Epimedium icariin (ICA) has been reported to modulate NF-κB signaling and astrocytic activation.

PURPOSE

The present study aimed to investigate the effects of ICA on post-HSR anxiety disorders and its potential mechanism of action.

METHODS

We first induced HSR in mice through a bleeding and re-transfusion model and selectively inhibited and activated astrocytes in the amygdala using chemogenetics. Then, ICA (40 mg/kg) was administered by oral gavage once daily for 21 days. Behavioral, electrophysiological, and pathological changes were assessed after HSR using the light-dark transition test, elevated plus maze, recording of local field potential (LFP), and immunofluorescence assays.

RESULTS

Exposure to HSR reduced the duration of the light chamber and attenuated open-arm entries. Moreover, HSR exposure increased the theta oscillation power in the amygdala and upregulated NF-κB p65, H3K27ac, and H3K4me3 expression. Contrarily, chemogenetic inhibition of astrocytes significantly reversed these changes. Chemogenetic inhibition in astrocytes was simulated by ICA, but chemogenetic activation of astrocytes blocked the neuroprotective effects of ICA.

CONCLUSION

ICA mitigated anxiety-like behaviors induced by HSR in mice via inhibiting astrocytic activation, which is possibly associated with NF-κB-induced epigenetic reprogramming.

Anti-aging effects of icariin and the underlying mechanisms: A mini-review

Aging is an extremely intricate and progressive phenomenon that is implicated in many physiological and pathological conditions. Icariin (ICA) is the main active ingredient of Epimedium and has exhibited multiple bioactivities, such as anti-tumor, neuroprotective, antioxidant, anti-inflammatory, and anti-aging properties. ICA could extend healthspan in both invertebrate and vertebrate models. In this review, the roles of ICA in protection from declined reproductive function, neurodegeneration, osteoporosis, aging intestinal microecology, and senescence of cardiovascular system will be summarized. Furthermore, the underlying mechanisms of ICA-mediated anti-aging effects will be introduced. Finally, we will discuss some key aspects that constrain the usage of ICA in clinical practice and the corresponding strategies to solve these issues.

Icaritin: A phytomolecule with enormous pharmacological values

Pharmacological studies on flavonoids have always drawn much interest for many years. Icaritin (ICT), a representative flavone containing an 8-prenyl group, is a principal compound detected in medicinal plants of the genus Epimedum, the family Berberidaceae. Experimental results in the phytochemistry and pharmacology of this molecule are abundant now, but a deep overview has not been carried out. The goal of this review is to provide an insight into the natural observation, biosynthesis, biotransformation, synthesis, pharmacology, and pharmacokinetics of prenyl flavone ICT. The relevant data on ICT was collected from bibliographic sources, like Google Scholar, Web of Science, Sci-Finder, and various published journals. "Icaritin" alone or in combination is the main keyword to seek for references, and references have been updated till now. ICT is among the characteristic phytomolecules of Epimedum plants. Bacteria monitored its biosynthesis and biotransformation, while this agent was rapidly synthesized from phloroglucinol by microwave-assistance Claisen rearrangement. ICT is a potential agent in numerous in vitro and in vivo pharmacological records, which demonstrated its role in cancer treatments via apoptotic-related mechanisms. It also brings in various health benefits since it reduced harmful effects on the liver, lung, heart, bone, blood, and skin, and improved immune responses. Pharmacokinetic outcomes indicated that its metabolic pathway involved hydration, hydroxylation, dehydrogenation, glycosylation, and glucuronidation. Molecule mechanisms of action at a cellular level are predominant, but clinical studies are expected to get more. Structure-activity relationship records seem insufficient, and the studies on nano-combined approaches to improve its soluble property in living bodied medium are needed.

Molecular mechanisms and therapeutic potential of icariin in the treatment of Alzheimer's disease

BACKGROUND

Icariin (ICA) is the main active component of Epimedium, a traditional Chinese medicine (TCM), known to enhance cognitive function in Alzheimer's disease (AD). This study aims to investigate and summarize the mechanisms through which ICA treats AD.

METHODS

The PubMed and CNKI databases were utilized to review the advancements in ICA's role in AD prevention and treatment by analyzing literature published between January 2005 and April 2023. To further illustrate ICA's impact on AD development, tables, and images are included to summarize the relationships between various mechanisms.

RESULTS

The study reveals that ICA ameliorates cognitive deficits in AD model mice by modulating Aβ via multiple pathways, including BACE-1, NO/cGMP, Wnt/Ca²⁺, and PI3K/Akt signaling. ICA exhibits neuroprotective properties by inhibiting neuronal apoptosis through the suppression of ER stress in AD mice, potentially linked to NF-κB, MAPK, ERK, and PERK/Eif2α signaling pathways. Moreover, ICA may safeguard neurons by attenuating mitochondrial oxidative stress injury. ICA can also enhance learning, memory, and cognition by improving synaptic structure via regulation of the PSD-95 protein. Furthermore, ICA can mitigate neuroinflammation by inactivating microglial activity through the upregulation of PPARγ, TAK1/IKK/NF-κB, and JNK/p38 MAPK signaling pathways.

CONCLUSION

This study indicates that ICA possesses multiple beneficial effects in AD treatment. Through the integration of pharmacological and molecular biological research, ICA may emerge as a promising candidate to expedite the advancement of TCM in the clinical management of AD.

Upregulation of glutamate transporter 1 by mTOR/Akt pathway in astrocyte culture during oxygen-glucose deprivation and reoxygenation

Astrocyte-specific glutamate transporter subtype 1 (GLT-1) plays an important role in influencing glutamate excitatory toxicity and preventing the death of excitatory toxic neurons. Although the mammalian target of rapamycin (mTOR)/protein kinase B(Akt)/nuclear factor kappa B signaling cascade is involved in the upregulation of astrocytic GLT-1 in oxygen-glucose deprivation (OGD), it is unclear whether the mTOR/Akt pathway is involved in astrocytic GLT-1 upregulation in OGD and reoxygenation (OGD/R). In this study, we found that the treatment of cultured astrocytes with rapamycin and triciribine led to the decreased astrocytes' protrusions, smaller nuclei, and an increased apoptotic rate. The inhibitors of mTOR complex 1 significantly increased the expression levels of phosphorylated Akt-Ser473 (p-Akt), phosphorylated Akt-Thr308(p-Akt), and GLT-1, while Akt-specific inhibitors blocked GLT-1 expression, suggesting that the mTOR/Akt pathway is involved in GLT-1 upregulation. We further demonstrated that astrocytes under OGD/R adapted to environmental changes through the mTOR/Akt pathway, mainly by altering cell morphology and apoptosis and upregulating the expression levels of p-Akt and GLT-1. Our results suggested that astrocytes may adapt to short-term ischemic-reperfusion injury by regulating cell morphology, apoptosis and GLT-1 upregulation.

A clinical herbal prescription Gu-Shu-Kang capsule exerted beneficial effects on the musculoskeletal system of dexamethasone-treated mice by acting on tissue IGF-1 signalling pathway

CONTEXT

Gu-Shu-Kang (GSK) is a clinical traditional Chinese medicine prescription for the treatment of primary osteoporosis.

OBJECTIVE

This study investigates the protection of GSK against dexamethasone (Dex)-induced disturbance of musculoskeletal system in male mice and to identify the underlying mechanism.

MATERIALS AND METHODS

Male C57BL/6 mice in Dex-treated groups were orally administered (i.g.) with vehicle, low dose (0.38 g/kg), middle dose (0.76 g/kg), or high dose (1.52 g/kg) of GSK for 8 weeks. A control group was designed without any treatment. The quadriceps femoris, tibialis anterior and gastrocnemius were harvested. Molecular expression was determined by RT-PCR and immunoblotting.

RESULTS

Treatment with GSK enhanced weight-loaded swimming time (from 411.7 ± 58.4 s in Dex group to 771.4 ± 87.3 s in GSK-M) and grip strength (from 357.8 ± 23.9 g in Dex group to 880.3 ± 47.6 g in GSK-M). GSK produced a rise in cross-sectional area of myofibers and promoted a switching of glycolytic-to-oxidative myofiber. The administration with GSK affected expression of muscle regulatory factors shown by the down-regulation in MuRF-1 and atrogin-1 and the up-regulation in myogenic differentiation factor (MyoD) and myosin heavy chain (MHC). GSK stimulated tissue IGF-1 signalling pathway (IGF-1R/PI3K/Akt), not only in skeletal muscle but also in bone associated with the amelioration of trabecular bone mineral density and the improvement of osteogenesis.

CONCLUSIONS

These findings revealed the potential mechanisms involved in the beneficial effects of Gu-Shu-Kang on musculoskeletal system in mice with challenging to dexamethasone, and this prescription may have applications in management for muscle atrophy and osteoporosis triggered by glucocorticoid.

Beneficial effects of natural flavonoids on neuroinflammation

Neuroinflammation is the fundamental immune response against multiple factors in the central nervous system and is characterized by the production of inflammatory mediators, activated microglia and astrocytes, and the recruitment of innate and adaptive immune cells to inflammatory sites, that contributes to the pathological process of related brain diseases, such as Alzheimer’s disease, Parkinson’s disease, depression, and stroke. Flavonoids, as a species of important natural compounds, have been widely revealed to alleviate neuroinflammation by inhibiting the production of pro-inflammatory mediators, elevating the secretion of anti-inflammatory factors, and modulating the polarization of microglia and astrocyte, mainly via suppressing the activation of NLRP3 inflammasome, as well as NF-κB, MAPK, and JAK/STAT pathways, promoting Nrf2, AMPK, BDNF/CREB, Wnt/β-Catenin, PI3k/Akt signals and SIRT1-mediated HMGB1 deacetylation. This review will provide the latest and comprehensive knowledge on the therapeutic benefits and mechanisms of natural flavonoids in neuroinflammation, and the natural flavonoids might be developed into food supplements or lead compounds for neuroinflammation-associated brain disorders.

Icariin: A Potential Lipid Metabolism Regulator in Osteoarthritis

Background: Icariin is a small molecule drug capable of treating osteoarthritis. Additionally, icariin is known to have an excellent ability to regulate lipid metabolism. A growing number of studies have demonstrated that lipid metabolism is related to the pathogenesis of osteoarthritis. Therefore, by regulating lipid metabolism, icariin may have a significant role in osteoarthritis. However, the molecular mechanism by which icariin regulates lipid metabolism in osteoarthritis is currently unknown. Understanding the molecular mechanism would be helpful in the treatment of osteoarthritis. Objective: This study aimed to explore the mechanism of icariin that regulated lipid metabolism in the treatment of osteoarthritis through a combination of molecular docking and network pharmacology. Methods: Firstly, potential targets for icariin were collected from the TCMSP database, Pharm Mapper, and Swiss Target Prediction Server. Targets for osteoarthritis and lipid metabolism were obtained in OMIM, DrugBank, and GeneCards databases. Common targets of icariin, osteoarthritis, and lipid metabolism were acquired by clusterProfiler R package software. We then constructed the drug-target-signaling pathway-disease network after performing GO and KEGG enrichment analyses of common targets. Finally, we performed molecular docking validation. To support our findings, a search of PubMed was performed to find relevant literature published within the last 5 years. Results: We obtained 12 targets that may be important in the regulation of lipid metabolism in osteoarthritis by icariin. Through PPI network analysis, it was determined that 5 core targets, including TNF, PTGS2, CCND1, MMP2, and ESR1, participated in this process. Molecular docking results showed that the icariin had a high affinity to the core target proteins. Relevant studies in the literature suggest that TNF, PTGS2, MMP2, and ESR1 are the core targets. Conclusion: Icariin is a potential modulator of lipid metabolism in osteoarthritis, and the molecular mechanism may be related to core targets such as TNF, PTGS2, MMP2, and ESR1.

Effect of icaritin on autophagy-related protein expression in TDP-43-transfected SH-SY5Y cells

Objective

To study the protective effect and mechanism of icaritin (ICT) in a SH-SY5Y cells with virus-loaded TAR DNA-binding domain protein 43(TDP-43) by examining the effect of ICT on the expression of autophagy-related proteins in TDP-43-infected SH-SY5Y cells.

Methods

A TDP-43-induced neuronal cell injury model was established by transfecting well-growing SH-SY5Y cells with virus loaded with the TDP-43 gene. The changes in cell viability were detected by the CCK-8 method. After successful transfection, the establishment of the model was verified by real-time quantitative PCR (qPCR) and Western blot methods. After the cells were subjected to drug intervention with ICT, the changes in the expression levels of TDP-43, cleaved Caspase-3, LC3 II/I, Beclin-1 and p62 were detected by Western blotting.

Results

After ICT intervention, it was found that compared with that of the TDP-43 group, the cell viability of the TDP-43+ICT group increased, the expression level of TDP-43 decreased, and the expression levels of the apoptotic protein cleaved Caspase-3, autophagy protein Beclin-1, and LC3-II/I decreased, while the expression level of the autophagy protein p62 increased.

Conclusion

ICT has a protective effect on the SH-SY5Y cell injury model transfected with TDP-43. This protective effect may be related to reducing the protein expression of TDP-43 and inhibiting autophagy.