Icariin attenuates lipopolysaccharide-induced microglial activation and resultant death of neurons by inhibiting TAK1/IKK/NF-kappaB and JNK/p38 MAPK pathways

Selenium alleviates lead-induced CIK cells pyroptosis and inflammation through IRAK1/TAK1/IKK pathway

The toxic heavy metal lead is widely found in rivers and soils as an environmental pollutant, posing a threat to the health of aquatic organisms. Selenium is an essential trace element and a powerful antioxidant that has been shown to have anti-inflammatory and antioxidant properties as well as alleviating heavy metal poisoning. Many studies have shown that lead poisoning produces inflammatory responses and damage to the kidneys of a wide range of animals, but the effects on cellular pyroptosis and immune function and selenium antagonism in CIK cells are not clear. In this study, 500 μM Pb and 20 nM Se were applied to grass carp kidney cells, and the results showed that Pb exposure to CIK cells resulted in oxidative stress, activation of the IRAK1/TAK1/IKK pathway, up-regulation of the expression of cellular pyroptosis markers GSDMD and NLRP3, and cellular pyroptosis of CIK cells, as well as up-regulation of IL-1β and IL-18, and the generation of cellular inflammatory response. In contrast, Se treatment significantly reduced the ROS level, the expression of cellular pyroptosis markers GSDMD, NLRP3 and inflammatory element IL-1β and IL-18. Taken together, Se alleviated cellular pyroptosis and immune dysfunction caused by Pb exposure through oxidative stress and activation of the IRAK1/TAK1/IKK pathway. This study complements the harmful effects of the heavy metal Pb on fish and the real-life application of selenium in the healthy culture of fish as a reference will be provided.

The dual face of microglia (M1/M2) as a potential target in the protective effect of nutraceuticals against neurodegenerative diseases

The pathophysiology of different neurodegenerative illnesses is significantly influenced by the polarization regulation of microglia and macrophages. Traditional classifications of macrophage phenotypes include the pro-inflammatory M1 and the anti-inflammatory M2 phenotypes. Numerous studies demonstrated dynamic non-coding RNA modifications, which are catalyzed by microglia-induced neuroinflammation. Different nutraceuticals focus on the polarization of M1/M2 phenotypes of microglia and macrophages, offering a potent defense against neurodegeneration. Caeminaxin A, curcumin, aromatic-turmerone, myricetin, aurantiamide, 3,6'-disinapoylsucrose, and resveratrol reduced M1 microglial inflammatory markers while increased M2 indicators in Alzheimer's disease. Amyloid beta-induced microglial M1 activation was suppressed by andrographolide, sulforaphane, triptolide, xanthoceraside, piperlongumine, and novel plant extracts which also prevented microglia-mediated necroptosis and apoptosis. Asarone, galangin, baicalein, and a-mangostin reduced oxidative stress and pro-inflammatory cytokines, such as interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha in M1-activated microglia in Parkinson's disease. Additionally, myrcene, icariin, and tenuigenin prevented the nod-like receptor family pyrin domain-containing 3 inflammasome and microglial neurotoxicity, while a-cyperone, citronellol, nobiletin, and taurine prevented NADPH oxidase 2 and nuclear factor kappa B activation. Furthermore, other nutraceuticals like plantamajoside, swertiamarin, urolithin A, kurarinone, Daphne genkwa flower, and Boswellia serrata extracts showed promising neuroprotection in treating Parkinson's disease. In Huntington's disease, elderberry, curcumin, iresine celosia, Schisandra chinensis, gintonin, and pomiferin showed promising results against microglial activation and improved patient symptoms. Meanwhile, linolenic acid, resveratrol, Huperzia serrata, icariin, and baicalein protected against activated macrophages and microglia in experimental autoimmune encephalomyelitis and multiple sclerosis. Additionally, emodin, esters of gallic and rosmarinic acids, Agathisflavone, and sinomenine offered promising multiple sclerosis treatments. This review highlights the therapeutic potential of using nutraceuticals to treat neurodegenerative diseases involving microglial-related pathways.

Therapeutic targeting of Ras/Raf/MAPK pathway by natural products: A systematic and mechanistic approach for neurodegeneration

BACKGROUND

Multiple dysregulated pathways are behind the pathogenesis of neurodegenerative diseases (NDDs); however, the crucial targets are still unknown. Oxidative stress, apoptosis, autophagy, and inflammation are the most dominant pathways that strongly influence neurodegeneration. In this way, targeting the Ras/Raf/mitogen-activated protein kinases (MAPKs) pathway appears to be a developing strategy for combating NDDs like Parkinson's disease, Alzheimer's disease, stroke, aging, and other NDDs. Accordingly, plant secondary metabolites have shown promising potentials for the simultaneous modulation of the Ras/Raf/MAPKs pathway and play an essential role in NDDs. MAPKs include p38 MAPK, extracellular signal-regulated kinase 1/2 (ERK 1/2), and c-Jun N-terminal kinase (JNK), which are important molecular players in neurodegeneration. Ras/Raf, which is located the upstream of MAPK pathway influences the initiation and progression of neurodegeneration and is regulated by natural products.

PURPOSE

Thus, the present study aimed to investigate the neuroprotective roles of plant- and marine-derived secondary metabolites against several NDDs through the modulation of the Ras/Raf/MAPK signaling pathway.

STUDY DESIGN AND METHODS

A systematic and comprehensive review was performed to highlight the modulatory roles of natural products on the Ras/Raf/MAPK signaling pathway in NDDs, according to the PRISMA guideline, using scholarly electronic databases, including PubMed, Scopus, and Web of Sciences. Associated reference lists were also searched for the literature review.

RESULTS

From a total of 1495 results, finally 107 articles were included in the present study. The results show that several natural compounds such as alkaloid, phenolic, terpenoids, and nanoformulation were shown to have modulatory effects on the Ras/Raf/MAPKs pathway.

CONCLUSION

Natural products are promising multi-targeted agents with on NDDs through Ras/Raf/MAPKs pathway. Nevertheless, additional and complementary studies are necessary to check its efficacy and potential side effects.

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.

Anti-Alzheimers molecular mechanism of icariin: insights from gut microbiota, metabolomics, and network pharmacology

BACKGROUND

Icariin (ICA), an active ingredient extracted from Epimedium species, has shown promising results in the treatment of Alzheimer's disease (AD), although its potential therapeutic mechanism remains largely unknown. This study aimed to investigate the therapeutic effects and the underlying mechanisms of ICA on AD by an integrated analysis of gut microbiota, metabolomics, and network pharmacology (NP).

METHODS

The cognitive impairment of mice was measured using the Morris Water Maze test and the pathological changes were assessed using hematoxylin and eosin staining. 16S rRNA sequencing and multi-metabolomics were performed to analyze the alterations in the gut microbiota and fecal/serum metabolism. Meanwhile, NP was used to determine the putative molecular regulation mechanism of ICA in AD treatment.

RESULTS

Our results revealed that ICA intervention significantly improved cognitive dysfunction in APP/PS1 mice and typical AD pathologies in the hippocampus of the APP/PS1 mice. Moreover, the gut microbiota analysis showed that ICA administration reversed AD-induced gut microbiota dysbiosis in APP/PS1 mice by elevating the abundance of Akkermansia and reducing the abundance of Alistipe. Furthermore, the metabolomic analysis revealed that ICA reversed the AD-induced metabolic disorder via regulating the glycerophospholipid and sphingolipid metabolism, and correlation analysis revealed that glycerophospholipid and sphingolipid were closely related to Alistipe and Akkermansia. Moreover, NP indicated that ICA might regulate the sphingolipid signaling pathway via the PRKCA/TNF/TP53/AKT1/RELA/NFKB1 axis for the treatment of AD.

CONCLUSION

These findings indicated that ICA may serve as a promising therapeutic approach for AD and that the ICA-mediated protective effects were associated with the amelioration of microbiota disturbance and metabolic disorder.

Retraction

Han N, Zhang B, Wei X, Yu L. The inhibitory function of icariin in cell model of benign prostatic hyperplasia by upregulation of miR-7. BioFactors. 2023;49:203. https://doi.org/10.1002/biof.1591 This article, published online on 29 November 2019 in Wiley Online Library, has been retracted by agreement between the International Union of Biochemistry and Molecular Biology, the Editor in Chief (Dr. Angelo Azzi), and Wiley Periodicals LLC. The retraction has been agreed following an investigation based on allegations raised by a third party. Evidence for image manipulation was found in figures 1, 3, 4, 5, 6, and 7. As a result, the conclusions of this article are considered to be invalid.

Neuroprotective Mechanism of Icariin on Hypoxic Ischemic Brain Damage in Neonatal Mice

Objective. Our previous results showed that icariin (ICA) could inhibit apoptosis and provide neuroprotection against hypoxic-ischemic brain damage (HIBD) in neonatal mice, but the specific mechanism of its neuroprotective effect remains unknown. This study aims at exploring whether ICA plays a neuroprotective role in apoptosis inhibition by regulating autophagy through the estrogen receptor α (ERα)/estrogen receptor β (ERβ) pathway in neonatal mice with HIBD. Methods. A neonatal mouse model of HIBD was constructed in vivo, and an oxygen and glucose deprivation (OGD) model in HT22 cells from the hippocampal neuronal system was constructed in vitro. The effects of ICA pretreatment on autophagy and the expression of ERα and ERβ were detected in vitro and in vivo, respectively. ICA pretreatment was also supplemented with the autophagy inhibitor 3-methyladenine (3-MA), ERα inhibitor methylpiperidino pyrazole (MPP), and ERβ inhibitor 4-(2-phenyl-5,7-bis (trifluoromethyl) pyrazolo [1,5-a] pyramidin-3-yl) phenol (PHTPP) to further detect whether ICA pretreatment can activate the ERα/ERβ pathway to promote autophagy and reduce HIBD-induced apoptosis to play a neuroprotective role against HIBD in neonatal mice. Results. ICA pretreatment significantly promoted autophagy in HIBD mice. Treatment with 3-MA significantly inhibited the increase in autophagy induced by ICA pretreatment, reversed the neuroprotective effect of ICA pretreatment, and promoted apoptosis. Moreover, ICA pretreatment significantly increased the expression levels of the ERα and ERβ proteins in HIBD newborn mice. Both MPP and PHTPP administration significantly inhibited the expression levels of the ERα and ERβ proteins activated by ICA pretreatment, reversed the neuroprotective effects of ICA pretreatment, inhibited the increase in autophagy induced by ICA pretreatment, and promoted apoptosis. Conclusion. ICA pretreatment may promote autophagy by activating the ERα and ERβ pathways, thus reducing the apoptosis induced by HIBD and exerting a neuroprotective effect on neonatal mice with HIBD.

Icariin Alleviates Escherichia coli Lipopolysaccharide-Mediated Endometritis in Mice by Inhibiting Inflammation and Oxidative Stress

Icariin (ICA) is a naturally occurring phytochemical agent primarily extracted from Epimedium Brevicornum Maxim (Family Berberidaceae) with a broad spectrum of bioactivities. Endometritis is a uterine disease that causes enormous losses in the dairy industry worldwide. In this study, anti-inflammatory and anti-oxidant properties of ICA were investigated against lipopolysaccharide (LPS)-induced endometritis in mice to investigate possible underlying molecular mechanisms. Sixty heathy female Kunming mice were randomly assigned to four groups (n = 15), namely control, LPS, LPS + ICA, and ICA groups. The endometritis was induced by intrauterine infusion of 50 µL of LPS (1 mg/mL). After 24 h of onset of LPS-induced endometritis, ICA groups were injected thrice by ICA intraperitoneally six hours apart. Histopathological examination, enzyme linked immunosorbent assay (ELISA), real time quantitative polymerase chain reaction (RT-qPCR), western blotting, and immunohistochemistry were used in this study. Histological alterations revealed that ICA markedly mitigated uterine tissue injury caused by LPS. The results showed that the ICA inhibited the production of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) and boosted the production of anti-inflammatory cytokines (IL-10). Additionally, ICA modulated the expression of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (Gpx1) induced by LPS. The administration of ICA significantly (p < 0.05) improved the mRNA and protein expression of Toll-like receptor (TLR) 4. The western blotting and ELISA finding revealed that the ICA repressed LPS-triggered NF-κB pathway activation. Moreover, ICA improved the antioxidant defense system via activation of the Nrf2 pathway. The results revealed that ICA up-regulated the mRNA and protein expression of Nuclear erythroid-2-related factor (Nrf2), NAD(P)H: quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and glutamate-cysteine ligase catalytic subunit (GCLC) under LPS exposure. Conclusively, our findings strongly suggested that ICA protects endometritis caused by LPS by suppressing TLR4-associated NF-κB and Nrf2 pathways. Altogether, these innovative findings may pave the way for future studies into the therapeutic application of ICA to protect humans and animals against endometritis.

Anti-inflammatory Mechanism of Action of Benzoylmesaconine in Lipopolysaccharide-Stimulated RAW264.7 Cells

Background

Benzoylmesaconine (BMA), the most abundant monoester alkaloid in Aconitum plants, has some biological activities and is a potential therapeutic agent for inflammation-related diseases. However, the potential anti-inflammatory mechanisms of BMA have not been clarified.

Purpose

This study aimed to investigate the underlying molecular mechanisms of the anti-inflammatory action of this compound using lipopolysaccharide (LPS)-activated RAW264.7 macrophages.

Methods

The release of pro-inflammatory cytokines and mediators were detected by nitric oxide (NO) assays, reactive oxygen species (ROS) assays, and enzyme-linked immunosorbent assays (ELISA) in LPS-activated RAW264.7 macrophage cells. Quantitative real-time PCR was used to measure the gene expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Cell viability was determined using a cell counting kit-8 (CCK-8) assay. The expression of iNOS, COX-2, mitogen-activated protein kinase (MAPK), and nuclear factor-κB (NF-κB)-related proteins were detected by western blot, and nuclear translocation of p65 was observed by immunofluorescence.

Results

BMA significantly decreased the production of IL-1β, IL-6, TNF-α, PGE₂, NO, and ROS and inhibited the protein and mRNA levels of COX-2 and iNOS in LPS-activated RAW264.7 macrophages. Moreover, LPS-induced phosphorylation of IκBα, JNK, p38, and ERK; degradation of IκBα; and nuclear translocation of p65 were significantly suppressed by BMA treatment.

Conclusion

These findings demonstrate that the anti-inflammatory effect of BMA was through the suppression of the NF-κB and MAPK signaling pathways and that it may be a therapeutic agent targeting specific signal transduction events required for inflammation-related diseases.

Icariin: A Potential Neuroprotective Agent in Alzheimer's Disease and Parkinson's Disease

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases worldwide. They are characterized by the loss of neurons and synapses in special parts of the central nervous system (CNS). There is no definitive treatment for AD and PD, but extensive studies are underway to identify the effective drugs which can slow the progression of these diseases by affecting the factors involved in their pathophysiology (i.e., aggregated proteins, neuroinflammation, and oxidative stress). Icariin, a natural compound isolated from Epimedii herba, is known because of its anti-inflammatory and anti-oxidant properties. In this regard, there are numerous studies indicating its potential as a natural compound against the progression of CNS disorders, such as neurodegenerative diseases. Therefore, this review aims to re-examine findings on the pharmacologic effects of icariin on factors involved in the pathophysiology of AD and PD.

Impact of Icariin and its derivatives on inflammatory diseases and relevant signaling pathways

Herba Epimedii is a famous herb collected from China and Korea. It has been used for impotency, osteoporosis, and amnestic treatment for thousands of years. Icariin, a typical flavonoid compound isolated from Herba Epimedii, was reported as a potential anti-inflammatory drug. Icariside and icaritin are the two metabolites of icariin. Icariin and its metabolites have been used to treat a wide range of inflammatory diseases, such as atherosclerosis, Alzheimer's disease, depression, osteoarthritis, and asthma. They exert powerful suppression of proinflammatory signaling, such as NF-κB and MAPKs. More importantly, they can upregulate anti-inflammatory signaling, such as GR and Nrf2. In this study, we review the therapeutic effects and mechanisms of icariin and its metabolites in inflammatory diseases and provide novel insights into these potential anti-inflammatory drugs.

The Research Progress in Physiological and Pathological Functions of TRAF4

Tumour necrosis factor receptor-associated factor 4 (TRAF4) is a member of the TRAF protein family, a cytoplasmic bridging molecule closely associated with various immune functions. The physiological processes of TRAF4 are mainly involved in embryonic development, cell polarity, cell proliferation, apoptosis, regulation of reactive oxygen species production. TRAF4 is overexpressed in a variety of tumors and regulates the formation and development of a variety of tumors. In this review, we summarize the physiological and pathological regulatory functions of TRAF4 and focus on understanding the biological processes involved in this gene, to provide a reference for further studies on the role of this gene in tumorigenesis and development.

Liensinine alleviates high fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) through suppressing oxidative stress and inflammation via regulating TAK1/AMPK signaling

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent liver diseases without effective pharmacological intervention. Liensinine (LIEN), a plant-derived isoquinoline alkaloid, exerts key roles in regulating various cellular processes. However, its potential on NAFLD progression has not been reported. In the study, we attempted to explore the regulatory effects of LIEN on fatty liver, and the underlying molecular mechanisms. Our in vitro experiments showed that LIEN treatments significantly reduced the lipid deposition in palmitate acid (PA)-treated cells by improving AMP-activated protein kinase (AMPK) activation. Additionally, excessive reactive oxygen species (ROS) generation was also strongly down-regulated by LIEN in cells upon PA stimulation through enhancing nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation. Moreover, PA-triggered inflammatory response was markedly restrained by LIEN via the blockage of TGF-β-activating kinase 1/nuclear factor-κB (TAK1/NF-κB) signaling. Intriguingly, we further found that LIEN-prohibited ROS production, lipid disorder and inflammation were largely dependent on AMPK activation through repressing TAK1. Consistently, our in vivo experiments confirmed that LIEN treatments efficiently improved the metabolic disorder, insulin resistance, dyslipidemia in high fat diet (HFD)-fed mice. Furthermore, HFD-triggered oxidative stress and inflammation in liver were greatly meliorated by LIEN administration by mediating Nrf2 and TAK1 signaling pathways, respectively. Collectively, all these findings demonstrated that LIEN exerted anti-dyslipidemia, anti-oxidant and anti-inflammatory effects to alleviate NAFLD progression mainly through modulating TAK1/AMPK signaling, and thus could be considered as a promising therapeutic strategy.

The neuroprotective effects of icariin on ageing, various neurological, neuropsychiatric disorders, and brain injury induced by radiation exposure

Epimedium brevicornum Maxim, a Traditional Chinese Medicine, has been used for the treatment of impotence, sinew and bone disorders, “painful impediment caused by wind-dampness,” numbness, spasms, hypertension, coronary heart disease, menopausal syndrome, bronchitis, and neurasthenia for many years in China. Recent animal experimental studies indicate that icariin, a major bioactive component of epimedium may effectively treat Alzheimer’s disease, cerebral ischemia, depression, Parkinson’s disease, multiple sclerosis, as well as delay ageing. Our recent study also suggested that epimedium extract could exhibit radio-neuro-protective effects and prevent ionizing radiation-induced impairment of neurogenesis. This paper reviewed the pharmacodynamics of icariin in treating different neurodegenerative and neuropsychiatric diseases, ageing, and radiation-induced brain damage. The relevant molecular mechanisms and its anti-neuroinflammatory, anti-apoptotic, anti-oxidant, as well as pro-neurogenesis roles were also discussed.

Icariin Ameliorates Alzheimer's Disease Pathology by Alleviating Myelin Injury in 3 × Tg-AD Mice

Alzheimer's disease (AD) is a neurodegenerative disease characterized by excessive deposition of β amyloid (Aβ), hyperphosphorylation of tau protein, and neuronal cell death. Recent studies have shown that myelin cell damage, which leads to cognitive dysfunction, occurs before AD-related pathological changes. Here, we examine the effect of icariin (ICA), a prenylated flavonol glycoside, in improving cognitive function in AD model mice. ICA has been reported to exhibit cardiovascular protective functions and antiaging effects. In this study, we used 3 × Tg-AD mice as an AD model. The Morris water maze and Y maze tests were performed to assess the learning and memory of the mice. Immunofluorescence analysis of Aβ1-42 deposition and myelin basic protein (MBP) expression in the mouse hippocampus was performed. Tau protein phosphorylation and MBP protein expression in the hippocampus were further analyzed by Western blotting. Myelin damage in the mouse optic nerve was evaluated by electron microscopy, and LFB staining was performed to assess myelin morphology in the mouse corpus callosum. MBP, Mpp5, and Egr2 transcript levels were quantified by qPCR. We observed that ICA treatment improved the learning and memory of 3 × Tg-AD mice and reduced Aβ deposition and tau protein phosphorylation in the hippocampus. Moreover, this treatment protocol increased myelin-related gene expression and reduced myelin damage.

The multifaceted NF-kB: are there still prospects of its inhibition for clinical intervention in pediatric central nervous system tumors?

Despite advances in the understanding of the molecular mechanisms underlying the basic biology and pathogenesis of pediatric central nervous system (CNS) malignancies, patients still have an extremely unfavorable prognosis. Over the years, a plethora of natural and synthetic compounds has emerged for the pharmacologic intervention of the NF-kB pathway, one of the most frequently dysregulated signaling cascades in human cancer with key roles in cell growth, survival, and therapy resistance. Here, we provide a review about the state-of-the-art concerning the dysregulation of this hub transcription factor in the most prevalent pediatric CNS tumors: glioma, medulloblastoma, and ependymoma. Moreover, we compile the available literature on the anti-proliferative effects of varied NF-kB inhibitors acting alone or in combination with other therapies in vitro, in vivo, and clinical trials. As the wealth of basic research data continues to accumulate, recognizing NF-kB as a therapeutic target may provide important insights to treat these diseases, hopefully contributing to increase cure rates and lower side effects related to therapy.

Understanding Abnormal c-JNK/p38MAPK Signaling Overactivation Involved in the Progression of Multiple Sclerosis: Possible Therapeutic Targets and Impact on Neurodegenerative Diseases

Demyelination, immune dysregulation, and neuroinflammation are the most common triggers of motor neuron disorders such as multiple sclerosis (MS). MS is a chronic demyelinating neurodegenerative disease of the central nervous system caused by abnormal immune activation, which causes myelin sheath damage. Cell signal transduction pathways are required for a variety of physiological and pathological processes in the brain. When these signaling systems become overactive, they can lead to disease progression. In various physiological conditions, abnormal mitogen-activated protein kinase (MAPK) activation is associated with several physiological dysfunctions that cause neurodegeneration. Previous research indicates that c-JNK and p38MAPK signaling play critical roles in neuronal growth and differentiation. c-JNK/p38MAPK is a member of the MAPK family, which regulates metabolic pathways, cell proliferation, differentiation, and apoptosis that control certain neurological activities. During brain injuries, c-JNK/p38MAPK also affects neuronal elastic properties, nerve growth, and cognitive processing. This review systematically linked abnormal c-JNK/p38MAPK signaling activation to multiple neuropathological pathways in MS and related neurological dysfunctions. MS progression is linked to genetic defects, oligodendrocyte destruction, glial overactivation, and immune dysregulation. We concluded that inhibiting both the c-JNK/p38MAPK signaling pathways can promote neuroprotection and neurotrophic effects against the clinical-pathological presentation of MS and influence other neurological disorders. As a result, the potential benefits of c-JNK/p38MAPK downregulation for the development of disease-modifying treatment interventions in the future could include MS prevention and related neurocomplications.

Benzoylaconine Modulates LPS-Induced Responses Through Inhibition of Toll-Like Receptor-Mediated NF-κB and MAPK Signaling in RAW264.7 Cells

Previous studies have shown that benzoylaconine (BAC), a representative monoester alkaloid, has a potential anti-inflammatory effect. This study investigated the underlying molecular mechanisms using the mode of LPS-activated RAW264.7 macrophage cells. Our findings showed that BAC significantly suppressed the release of pro-inflammatory cytokines and mediators, including IL-6, TNF-α, IL-1β, ROS, NO, and PGE₂. BAC treatment also effectively downregulated the elevated protein levels of iNOS and COX-2 induced by LPS in a dose-dependent manner. In this study, we found that BAC inhibited LPS-induced NF-κB activation by reducing the phosphorylation and degradation of IκBα by western blotting and blocking the nuclear translocation of p65 using an immunofluorescence assay. The elevated protein levels of JNK, p38, and ERK phosphorylation after LPS stimulation were restored effectively by BAC treatment. The protein expression of Toll-like receptor 4 (TLR4) and LPS-induced phosphorylation of TAK1, which is a crucial upstream regulatory factor of TLR-induced MAPK and NF-κB signaling, were inhibited by BAC in activated RAW264.7 macrophages. Moreover, BAC decreased the levels of TAK1 phosphorylation and pro-inflammatory cytokines and mediators associated with MAPK and NF-κB activation, similar to TLR4 inhibitor TAK-242. These findings demonstrated that BAC exhibited an anti-inflammatory effect by the inhibition of TLR-induced MAPK and NF-κB pathways, indicating that it could potentially be used for treating inflammatory diseases.

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

Icariin and icaritin, the major active components of Epimedii Genus, are considered as promising drugs with anti-inflammatory, anti-aging and neuroprotective effects. Our previous studies have demonstrated that icariin and icaritin can protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/1-methyl-4-phenylpyridinium (MPP⁺)-induced neurotoxicity on dopaminergic neurons via insulin-like growth factor-1 receptor (IGF-1 receptor) signaling. In the present study, we aimed to evaluate the role of IGF-1 receptor signaling in mediating the anti-inflammatory effects of icariin and icaritin against lipopolysaccharide (LPS)-induced neuroinflammation as well as their biological regulation effects in midbrain primary astrocytes. Our results showed that both icariin and icaritin significantly inhibited LPS-induced mRNA expressions of tumor necrosis factor (TNF-α) and interleukin-1β (IL-1β). Pre-treatment with IGF-1 receptor antagonist JB-1 could significantly block the anti-inflammatory effects of icariin and icaritin on LPS-induced up-regulations of TNF-α, IL-1β, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). Under basal conditions of astrocytes, icariin and icaritin treatment alone increased the phosphorylation of ERK1/2 and AKT, which could be blocked by JB-1. Moreover, the mRNA expressions of glutamate transptor-1 (GLT-1) and glutamate-aspartate transporter (GLAST) could be up-regulated by icariin and icaritin in a time-dependent manner via IGF-1 receptor. Taken together, our results suggest for the first time that both icariin and icaritin exert regulatory effects in astrocytes under basal conditions and after an inflammatory challenge via IGF-1 receptor signaling pathway.

Evaluation of Anti-inflammatory Nutraceuticals in LPS-induced Mouse Neuroinflammation Model: An Update

It is known that peripheral infections, accompanied by inflammation, represent significant risk factors for the development of neurological disorders by modifying brain development or affecting normal brain aging. The acute effects of systemic inflammation on progressive and persistent brain damage and cognitive impairment are well documented. Anti-inflammatory therapies may have beneficial effects on the brain, and the protective properties of a wide range of synthetic and natural compounds have been extensively explored in recent years. In our previous review, we provided an extensive analysis of one of the most important and widely-used animal models of peripherally induced neuroinflammation and neurodegeneration - lipopolysaccharide (LPS)-treated mice. We addressed the data reproducibility in published research and summarized basic features and data on the therapeutic potential of various natural products, nutraceuticals, with known anti-inflammatory effects, for reducing neuroinflammation in this model. Here, recent data on the suitability of the LPS-induced murine neuroinflammation model for preclinical assessment of a large number of nutraceuticals belonging to different groups of natural products such as flavonoids, terpenes, non-flavonoid polyphenols, glycosides, heterocyclic compounds, organic acids, organosulfur compounds and xanthophylls, are summarized. Also, the proposed mechanisms of action of these molecules are discussed.

Methylmercury induces neuronal cell death by inducing TNF-α expression through the ASK1/p38 signaling pathway in microglia

We recently found that tumor necrosis factor-α (TNF-α) may be involved in neuronal cell death induced by methylmercury in the mouse brain. Here, we examined the cells involved in the induction of TNF-α expression by methylmercury in the mouse brain by in situ hybridization. TNF-α-expressing cells were found throughout the brain and were identified as microglia by immunostaining for ionized calcium binding adaptor molecule 1 (Iba1). Methylmercury induced TNF-α expression in mouse primary microglia and mouse microglial cell line BV2. Knockdown of apoptosis signal-regulating kinase 1 (ASK1), an inflammatory cytokine up-regulator that is responsible for reactive oxygen species (ROS), decreased methylmercury-induced TNF-α expression through decreased phosphorylation of p38 MAP kinase in BV2 cells. Suppression of methylmercury-induced reactive oxygen species (ROS) by antioxidant treatment largely abolished the induction of TNF-α expression and phosphorylation of p38 by methylmercury in BV2 cells. Finally, in mouse brain slices, the TNF-α antagonist (WP9QY) inhibited neuronal cell death induced by methylmercury, as did the p38 inhibitor SB203580 and liposomal clodronate (a microglia-depleting agent). These results indicate that methylmercury induces mitochondrial ROS that are involved in activation of the ASK1/p38 pathway in microglia and that this is associated with induction of TNF-α expression and neuronal cell death.

Narciclasine inhibits LPS-induced neuroinflammation by modulating the Akt/IKK/NF-κB and JNK signaling pathways

BACKGROUND

Neuroinflammation is defined as innate immune system activation in the central nervous system, and is a complex response involved in removing pathogens, toxic components, and dead cells by activating microglial cells. However, over-activated microglia have been implicated in the pathogenesis of neurodegenerative diseases, because they release large amounts of neurotoxic factors. Thus, inhibiting microglial activation may represent an attractive approach for preventing neuroinflammatory disorders. The objective of this study was to investigate the effect of narciclasine (NA) on lipopolysaccharide (LPS)-induced neuroinflammation by evaluating related markers and neurotoxic factors.

METHODS

BV-2 cells were pre-incubated with NA at 0.1, 0.2, and 0.3 µM for 1h, and then co-treated with LPS for 12 h. Cellular medium and lysates were measured using a nitric oxide assay, enzyme-link immunosorbent assay (ELISA), western blotting, kinase activity assay, luciferase assay, and immunofluorescence assay. C57BL/6N mice were orally administered NA and intraperitoneally injected with LPS, and the cerebral cortex was examined using western blotting and immunofluorescence assays.

RESULTS

NA showed novel pharmacological activity, inhibiting pro-inflammatory factors, including TNF-α, IL-6, IL-18, NO, and PGE₂, but increasing the anti-inflammatory cytokines IL-10 and TGF-β1 in LPS-induced microglial cells. Moreover, NA also attenuated the LPS-induced mRNA and proteins of iNOS and COX-2. The mechanistic study indicated that NA attenuates the secretion of pro-inflammatory factor by down-regulating the Akt/IKK/NF-κB and JNK signaling pathways, and directly inhibits the catalytic activity of IKKα/β. Furthermore, we found that NA also reduced the expression of the microglial markers Iba-1, COX-2, and TNF-α in the mouse brain.

CONCLUSION

NA inhibits the over-expression of pro-inflammatory factors but it promotes anti-inflammatory cytokines by down-regulating the Akt/IKK/NF-κB and JNK signaling pathways in experimental models. Thus, NA may be a potential candidate for relieving neuroinflammation.

Icariin stimulates osteogenesis and suppresses adipogenesis of human bone mesenchymal stem cells via miR-23a-mediated activation of the Wnt/β-catenin signaling pathway

BACKGROUND

Icariin (ICA) is a bioactive compound isolated from epimedium-derived flavonoids that modulates bone mesenchymal stem cell osteogenesis and adipogenesis. However, its precise mechanism in this process is unknown.

PURPOSE

The purpose of this study was to elucidate the role of ICA on human bone mesenchymal stem cell (hBMSC) osteogenesis and adipogenesis by focusing on miR-23a mediated activation of the Wnt/β-catenin signaling pathway.

METHODS

After ICA treatment, hBMSC osteogenesis and adipogenesis were evaluated using alkaline phosphatase staining, an alkaline phosphatase activity assay, Oil Red O staining, and cellular triglyceride levels. Moreover, the mRNA and protein expression levels of osteogenic and adipogenic markers as well as key factors of the Wnt/β-catenin signaling pathway were measured using quantitative reverse transcription polymerase chain reaction and western blotting. Lithium chloride, an activator of the Wnt/β-catenin signaling pathway, was used as a positive control. Finally, to investigate the role of miR-23a in ICA-induced activation of the Wnt/β-catenin signaling pathway, hBMSCs were transfected with miR-23a mimics or a miR-23a inhibitor.

RESULTS

ICA significantly promoted hBMSC osteogenic differentiation by upregulating alkaline phosphatase activity and the expression of bone sialoprotein II (BSPII) and runt-related transcription factor-2 (Runx-2). In contrast, ICA inhibited hBMSC adipogenic differentiation by reducing lipid droplet formation and cellular triglyceride levels as well as by downregulating the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and CCAAT enhancer-binding protein-α (C/EBP-α). ICA mediated its effects on hBMSCs by activating the Wnt/β-catenin signaling pathway. It did so by upregulating β-catenin, low density lipoprotein receptor-related protein 5 (LRP5), and T cell factor 1 (TCF1). Notably, the up-regulation of these proteins was blocked by Dickkopf-related protein 1 (DKK1). Critically, the effects of ICA on hBMSCs were similar to that of the positive control, lithium chloride. Notably, ICA-induced activation of the Wnt/β-catenin signaling pathway was significantly attenuated following miR-23a up-regulation. Conversely, miR-23a downregulation affected hBMSCs in the same manner as ICA; i.e., it activated the Wnt/β-catenin signaling pathway.

CONCLUSION

ICA promotes and inhibits, respectively, hBMSC osteogenesis and adipogenesis via miR-23a-mediated activation of the Wnt/β-catenin signaling pathway.

A Placebo-Controlled, Pseudo-Randomized, Crossover Trial of Botanical Agents for Gulf War Illness: Reishi Mushroom (Ganoderma lucidum), Stinging Nettle (Urtica dioica), and Epimedium (Epimedium sagittatum)

This report is third in a three-part clinical trial series screening potential treatments for Gulf War Illness (GWI). The goal of the project was to rapidly identify agents to prioritize for further efficacy research. We used a placebo-controlled, pseudo-randomized, crossover design to test the effects of reishi mushroom (Ganoderma lucidum), stinging nettle (Uritca dioica), and epimedium (Epimedium sagittatum) in 29 men with GWI. Participants completed 30 days of symptom reports for baseline, then a botanical line consisting of 30 days of placebo, followed by 30 days each of lower-dose and higher-dose botanical. After completing a botanical line, participants were randomized to complete the protocol with another botanical, until they completed three botanical trials. GWI symptom severity, pain, and fatigue were contrasted between the four conditions (baseline, placebo, lower-dose, higher dose) using linear mixed models. GWI symptom severity was unchanged from placebo in the reishi lower-dose condition (p = 0.603), and was higher in the higher-dose condition (p = 0.012). Symptom severity was not decreased from placebo with lower-dose stinging nettle (p = 0.604), but was significantly decreased with higher-dose stinging nettle (p = 0.048). Epimedium showed no significant decreases of GWI symptoms in the lower (p = 0.936) or higher (p = 0.183) dose conditions. Stinging nettle, especially at higher daily dosages, may help reduce the symptoms of GWI. Epimedium does not appear to beneficially affect GWI symptom severity, and reishi may exaggerate symptoms in some GWI sufferers. These results are in a small sample and are preliminary. Further research is required to determine if stinging nettle is indeed helpful for the treatment of GWI, and what dosage is optimal. This trial was registered on ClinicalTrials.gov (NCT02909686).

Flavonoids, the compounds with anti-inflammatory and immunomodulatory properties, as promising tools in multiple sclerosis (MS) therapy: A systematic review of preclinical evidence

Multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), an animal model of MS, are diseases resulting in neurological disabilities that are regarded as chronic, inflammatory, and autoimmune diseases of central nervous system (CNS). In this respect, the use of anti-inflammatory compounds including flavonoids, polyphenolic compounds abundantly found in vegetables and fruits, has proposed to combat MS to dampen the inflammation and thereby ameliorating the disease severity. The objective of this study was to clarify the probable therapeutic effect of flavonoids for treatment of MS. Therefore, only English published articles that reported the therapeutic effect of flavonoids alone or in combination with other anti-MS therapeutic agents on MS, were selected by searching scientific electronic databases including PubMed, Scopus and Web of Science. Evaluation of the selected researches (686) showed that a total of 13 studies were suitable to be included in this systematic review. Interestingly, all of the studies (11 studies concerning EAE and 2 studies concerning MS) reported positive outcomes for the therapeutic effect of flavonoids on EAE and MS. All flavonoid compounds which are mentioned herein could successfully decrease the maximum clinical score of EAE, which is particularly connected to the anti-inflammatory property of these compounds. The literature review clearly discloses that flavonoids alone or in combination with other anti-MS therapeutic agents can pave the way for improving MS therapeutic strategies.

Dietary phytochemicals that influence gut microbiota: Roles and actions as anti-Alzheimer agents

The last decide has witnessed a growing research interest in the role of dietary phytochemicals in influencing the gut microbiota. On the other hand, recent evidence reveals that dietary phytochemicals exhibit properties of preventing and tackling symptoms of Alzheimer's disease, which is a neurodegenerative disease that has also been linked with the status of the gut microbiota over the last decade. Till now, little serious discussions, however, have been made to link recent understanding of Alzheimer's disease, dietary phytochemicals and the gut microbiota together and to review the roles played by phytochemicals in gut dysbiosis induced pathologies of Alzheimer's disease. Deciphering these connections can provide insights into the development and future use of dietary phytochemicals as anti-Alzheimer drug candidates. This review aims at presenting latest evidence in the modulating role of phytochemicals in the gut microbiota and its relevance to Alzheimer's disease and summarizing the mechanisms behind the modulative activities. Limitations of current research in this field and potential directions will also be discussed for future research on dietary phytochemicals as anti-Alzheimer agents.

Regulation of SIRT3 on mitochondrial functions and oxidative stress in Parkinson's disease

Sirtuin-3 (SIRT3) is a NAD⁺-dependent protein deacetylase that is located in mitochondria, regulating mitochondrial proteins and maintaining cellular antioxidant status. Increasing evidence demonstrates that SIRT3 plays a role in degenerative disorders including Parkinson's disease (PD), which is a devastating nervous system disease currently with no effective treatments available. Although the etiology of PD is still largely ambiguous, substantial evidence indicates that mitochondrial dysfunction and oxidative stress play major roles in the pathogenesis of PD. The imbalance of reactive oxygen species (ROS) production and detoxification leads to oxidative stress that can accelerate the progression of PD. By causing conformational changes in the deacetylated proteins SIRT3 modulates the activities and biological functions of a variety of proteins involved in mitochondrial antioxidant defense and various mitochondrial functions. Increasingly more studies have suggested that upregulation of SIRT3 confers beneficial effect on neuroprotection in various PD models. This review discusses the mechanism by which SIRT3 regulates intracellular oxidative status and mitochondrial function with an emphasis in discussing in detail the regulation of SIRT3 on each component of the five complexes of the mitochondrial respiratory chain and mitochondrial antioxidant defense, as well as the pharmacological regulation of SIRT3 in light of therapeutic strategies for PD.

Silymarin alleviates docetaxel-induced central and peripheral neurotoxicity by reducing oxidative stress, inflammation and apoptosis in rats

Docetaxel (DTX) is a chemotherapeutic agent used in the treatment of various malignancies but is often associated with central and peripheral neurotoxicity. The aim of this study was to investigate the neuroprotective effect of silymarin (SLM) against DTX-induced central and peripheral neurotoxicities in rats. Rats received 25 and 50 mg/kg body weight SLM orally for seven consecutive days after receiving a single injection of 30 mg/kg body weight DTX on the first day. SLM significantly decreased brain lipid peroxidation level and ameliorated brain glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities in DTX-administered rats. SLM attenuated levels of nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), glial fibrillary acidic protein (GFAP) and activity of p38α mitogen-activated protein kinase (p38α MAPK) whereas caused an increase in levels of neural cell adhesion molecule (NCAM) in the brain and sciatic nerve of DTX-induced rats. In addition, SLM improved the histological structure of the brain and sciatic nerve tissues and decreased the expression of c-Jun N-terminal kinase (JNK) in the sciatic nerve whereas increased cyclic AMP response element binding protein (CREB) expression in the brain induced by DTX. Additionally, SLM markedly up-regulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and B-cell lymphoma-2 (Bcl-2) and downregulated the expression of Bcl-2 associated X protein (Bax) in the brain and sciatic nerve tissues of DTX-induced rats. Our results show that SLM can protect DTX-induced brain and sciatic nerve injuries by enhancing the antioxidant defense system and suppressing apoptosis and inflammation.

The antioxidant icariin protects porcine oocytes from age-related damage in vitro

OBJECTIVE

If fertilization does not occur within a specific period, the quality of unfertilized oocytes in the oviduct (in vivo aging) or in culture (in vitro aging) will deteriorate over time. Icariin (ICA), found in all species of Epimedium herbs, has strong antioxidant activity, and is thought to exert anti-aging effects in vitro. We asked whether ICA protects oocytes against age-related changes in vitro.

METHODS

We analyzed the reactive oxygen species (ROS) levels and expression of antioxidant, maternal, and estrogen receptor genes, and along with spindle morphology, and the developmental competence and quality of embryos in the presence and absence of ICA.

RESULTS

Treatment with 5 μM ICA (ICA-5) led to a significant reduction in ROS activity, but increased mRNA expression of glutathione and antioxidant genes (superoxide dismutase 1 [SOD1], SOD2, peroxiredoxin 5, and nuclear factor erythroid 2-like 2), during aging in vitro. In addition, ICA-5 prevented defects in spindle formation and chromosomal alignment, and increased mRNA expression of cytoplasmic maturation factor genes (bone morphogenetic protein 15, cyclin B1, MOS proto-oncogene, serine/threonine kinase, and growth differentiation factor-9). It also prevented apoptosis, increased mRNA expression of antiapoptotic genes (BCL2-like 1 and baculoviral IAP repeat-containing 5), and reduced mRNA expression of pro-apoptotic genes (BCL2 antagonist/killer 1 and activation of caspase-3). Although the maturation and cleavage rates were similar in all groups, the total cell number per blastocyst and the percentage of apoptotic cells at the blastocyst stage were higher and lower, respectively, in the control and ICA-5 groups than in the aging group.

CONCLUSION

ICA protects oocytes against damage during aging in vitro; therefore, it can be used to improve assisted reproductive technologies.

Neurovascular glucocorticoid receptors and glucocorticoids: implications in health, neurological disorders and drug therapy

Glucocorticoid receptors (GRs) are ubiquitous transcription factors widely studied for their role in controlling events related to inflammation, stress and homeostasis. Recently, GRs have reemerged as crucial targets of investigation in neurological disorders, with a focus on pharmacological strategies to direct complex mechanistic GR regulation and improve therapy. In the brain, GRs control functions necessary for neurovascular integrity, including responses to stress, neurological changes mediated by the hypothalamic-pituitary-adrenal axis and brain-specific responses to corticosteroids. Therefore, this review will examine GR regulation at the neurovascular interface in normal and pathological conditions, pharmacological GR modulation and glucocorticoid insensitivity in neurological disorders.

Effects of dietary supplementation with icariin on growth performance, antioxidant capacity and non-specific immunity of Chinese mitten crab (Eriocheir sinensis)

We investigated the effects of icariin (ICA) on growth performance, antioxidant capacity and non-specific immunity in Chinese mitten crab (Eriocheir sinensis). A total of 200 healthy crabs (average weight: 33.58 ± 0.05 g) were randomly assigned to four treatments with five replicates, each with ten individuals per pool. There were four dietary treatments: the control group (fed with the basal diet), the ICA 50 group, the ICA100 group, and the ICA 200 group (fed with the basal diet supplemented with 50, 100, and 200 mg/kg ICA, respectively). These diets were provided for 8 weeks. Results indicated that ICA100 crabs had higher weight gain (WG), specific growth rate (SGR) and survival rate (SR) than the controls. Protein carbonyl content (PCC) and malondialdehyde (MDA) concentrations in the haemolymph and hepatopancreas of ICA100 crabs were significantly lower than in the control group, while the superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were significantly higher. The activities of PO, LZM, ACP and AKP were significantly enhanced with ICA supplementation at 50 and 100 mg/kg, yet decreased subsequently at 200 mg/kg. Furthermore, supplementation of 100 mg/kg ICA up-regulated the mRNA expression of prophenoloxidase (proPO), catalase (CAT), mitochondrial manganese superoxide dismutase (mtMnSOD), thioredoxin-1 (Trx1) and peroxiredoxin 6 (Prx6), while the mRNA expression of toll like receptors (TLRs), NF-κB-like transcription factor Relish and lipopolysaccharide-induced TNF-α factor (LITAF) were down-regulated in the hepatopancreas (P < 0.05). These findings indicate that dietary ICA supplementation at an optimum dose of 100 mg/kg may be effective in improving growth performance, antioxidant capability and non-specific immunity of Chinese mitten crab.

Icariin-mediated activation of autophagy confers protective effect on rotenone induced neurotoxicity in vivo and in vitro

Rotenone (ROT) is an environmental neurotoxin which has been demonstrated to cause characteristic loss of dopamine (DA) neurons in Parkinson's disease (PD). Icariin (ICA) is a flavonoid glucoside isolated from Herba Epimedii that has been shown to display neuroprotective functions. The present study evaluated protective effects of ICA on ROT-induced neurotoxicity and determined the modulation of ICA on the regulation of autophagy in vivo and in vitro. Rats were treated with ROT (1.0 mg/kg/day) with a co-administration of ICA (15 or 30 mg/kg/day) for 5 weeks. Immunohistochemical analysis showed a significant loss in DA neurons in the substantia nigra (SN) of rats treated with ROT, accompanied by an increase in the accumulation of α-synuclein and a compromised mitochondrial respiration. However, co-administration of ICA potently ameliorated the ROT-induced neuronal cell injury and improved mitochondrial function and decreased the accumulation of α-synuclein. ROT treatment resulted in a decrease in the protein expression of LC3-II and Beclin-1, and an increase in the protein level of P62, and upregulated the activation of mammalian target of rapamycin (mTOR), whereas ICA significantly reversed these aberrant changes caused by ROT. Furthermore, the neuroprotective effect of ICA was further verified in PC12 cells. Cells treated with ROT displayed an increased cytotoxicity and a decreased oxygen consumption which were rescued by the presence of ICA. Furthermore, ROT decreased the protein expression level of LC3-II, enhanced Beclin-1 expression, and activated phosphorylation of mTOR, whereas ICA markedly reversed this dysregulation of autophagy caused by ROT in the PC12 cells. Collectively, these results suggest that ICA mediated activation of autophagic flux confers a neuroprotective action on ROT-induced neurotoxicity.

Natural products as a potential modulator of microglial polarization in neurodegenerative diseases

Neurodegenerative diseases (NDs) are characterized by the progressive loss of structure and function of neurons most common in elderly population, mainly including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). Neuroinflammation caused by microglia as the resident macrophages of the central nervous system (CNS) plays a contributory role in the onset and progression of NDs. Activated microglia, as in macrophages, to be heterogeneous, can polarize into M1 (pro-inflammatory) and M2 (anti-inflammatory) functional phenotypes. The former elaborate pro-inflammatory mediators promoting neuroinflammation and neuronal damage. In contrast, the latter generate anti-inflammatory mediators and neurotrophins that inhibit neuroinflammation and promote neuronal healing. Consistently, the regulation of microglial polarization from M1 to M2 phenotype appears as an outstanding therapeutic and preventive approach for NDs treatment. Although non-steroidal anti-inflammatory drugs (NSAIDs) currently used to alleviate M1 microglia-associated neuroinflammation responsible for the development of NDs, these drugs have different degrees of adverse effects and limited efficacy. As the advantages of novel structure, multi-target, high efficiency and low toxicity, natural products as the modulators of microglial polarization have attracted considerable concerns in the therapeutic areas of NDs. In this review, we mainly summarized the therapeutic potential of natural products and their various molecular mechanisms for NDs treatment through modulating microglial polarization. The aim of the current review is expected to be useful to develop innovative modulators of microglial polarization from natural products for the amelioration and treatment of NDs.

Shared KEGG pathways of icariin-targeted genes and osteoarthritis

The beneficial effects of icariin in the management of many diseases, such as chronic renal failure and heart failure, are well known. Icariin has also been shown to ameliorate osteoarthritis (OA) symptoms; however, the underlying mechanisms remain unclear. In this study, a bioinformatics analysis was performed to investigate the KEGG pathways of icariin-targeted genes involved in OA. Our study suggests that icariin plays a role in OA by regulating inflammatory cytokine production, insulin resistance, and cell survival through modulation of the NF-κB, MAPK, and Akt signaling pathways. Importantly, IKBKB, NFKBIA, MAPK8, MAPK9, and MAPK10 may be the hub genes affected by icariin when providing its beneficial effects on OA. In addition, we found that icariin decreases proinflammatory factors and inhibits chondrocyte apoptosis through suppression of the NF-κB pathway. Our study highlights a set of KEGG pathways that could explain the molecular mechanism of icariin's action on OA, suggesting that icariin could be considered as a promising therapeutic option for OA.

Icariin and Its Metabolites as Potential Protective Phytochemicals Against Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder affecting more than 35 million people worldwide. As the prevalence of AD is dramatically rising, there is an earnest need for the identification of effective therapies. Available drug treatments only target the symptoms and do not halt the progression of this disorder; thus, the use of natural compounds has been proposed as an alternative intervention strategy. Icariin, a prenylated flavonoid, has several therapeutic effects, including osteoporosis prevention, sexual dysfunction amelioration, immune system modulation, and improvement of cardiovascular function. Substantial studies indicate that icariin may be beneficial to AD by reducing the production of extracellular amyloid plaques and intracellular neurofibrillary tangles and inhibiting phosphodiesterase-5 activity. Moreover, increasing evidence has indicated that icariin exerts a protective role in AD also by limiting inflammation, oxidative stress and reducing potential risk factors for AD such as atherosclerosis. This mini-review discusses the multiple potential mechanisms of action of icariin on the pathobiology of AD including explanation regarding its bioavailability, metabolism and pharmacokinetic.

PUFA-Plasmalogens Attenuate the LPS-Induced Nitric Oxide Production by Inhibiting the NF-kB, p38 MAPK and JNK Pathways in Microglial Cells

The special lipids plasmalogens (Pls) were reported to be reduced in the neurodegenerative brains such as Alzheimer's disease where a marked increase of glial activation is often observed. We previously found that a reduction of brain Pls can enhance the glial activation in murine brains. However, the detailed role of Pls in the prevention of glial activation was mostly elusive. Here we report that the Pls, extracted from scallop (sPls), significantly inhibited the inducible form of nitric oxide synthase (NOS2) and the production of NO in LPS (lipopolysaccharide)-activated microglial cells. We also observed that the polyunsaturated docosahexaenoic acid (DHA)-containing Pls but not the monounsaturated oleic acid-containing Pls attenuated the NOS2 induction. In addition, sPls blocked the activation of nuclear factor (NF)-kB and mitogen-activated protein kinases (MAPKs) e.g., JNK and p38 MAPK, thereby attenuated the nuclear translocation of NF-kB subunit, p65, and activator protein-1 (AP-1) proteins (c-Fos and c-Jun). Interestingly, LPS treatments suppressed the expression of Pls synthesizing enzymes, glycerone phosphate O-acyltransferase (GNPAT) and alkylglycerone phosphate synthase (AGPS) in the microglial cells by the p38MAPK and JNK pathways. Furthermore, the knockdown of GNPAT and AGPS genes by sh-RNAs accelerated the LPS-induced activation of p38MAPK and JNK, resulting in the increased production of NO. These findings suggested that a decrease of brain Pls can activate the NF-kB, p38MAPK and JNK pathways to induce a prolonged microglial activation which may downplay the neuroprotective events in the brains of neurodegenerative diseases.

Icariin, a flavonoid with anti-cancer effects, alleviated paclitaxel-induced neuropathic pain in a SIRT1-dependent manner

Background

One of the most common side effects of paclitaxel was dosage-dependently painful neuropathy. Various reports indicated that spinal neuroinflammation was involved in paclitaxel-induced neuropathic pain. This study investigated the effect of icariin on paclitaxel-induced neuroinflammation and peripheral neuropathy in rats.

Methods

Two parts were included in this study. In part one, the effect of icariin on paclitaxel-induced neuropathic pain was investigated. Mechanical thresholds were measured as primary outcomes. Production of proinflammatory factors (tumor necrosis factor-α, interleukin-1 β, and interleukin-6), activation of nuclear factor-κB (NF-κB(p65)) signal, and activation of astrocytes were detected as secondary outcomes. Spinal Sirtuin 1 (SIRT1) expression, H4 acetylation, and NAD⁺ content were measured to investigate the effect of icariin on spinal SIRT1 signal pathway. In part two, the role of SIRT1 signal on icariin-induced effect in rats was investigated, and EX527, a SIRT1 inhibitor, was employed.

Results

The results showed paclitaxel treatment induced significant decrease in mechanical thresholds. Paclitaxel treatment also induced NF-κB(p65) activation and upregulation of proinflammatory factors (TNF-α, IL-1β, and IL-6). Paclitaxel also induced astrocyte activation in the spinal cord. However, 100 mg/kg icariin treatment significantly alleviated paclitaxel-induced mechanical allodynia and spinal neuroinflammation. Furthermore, icariin treatment dosage-dependently reversed paclitaxel-induced SIRT1 downregulation and H4 acetylation. EX527, a selective SIRT1 inhibitor, completely reversed icariin-induced anti-neuroinflammation and anti-allodynia effects in paclitaxel-induced neuropathic pain rats.

Conclusions

This meant that spinal SIRT1 activation was involved in icariin-induced effects in paclitaxel-induced neuropathic pain rats. Icariin could be a potential agent for the treatment of paclitaxel-induced neuropathic pain.

An outline for the pharmacological effect of icariin in the nervous system

Icariin is a major active component of the traditional herb Epimedium, also known as Horny Goat Weed. It has been extensively studied throughout the past several years and is known to exert anti-oxidative, anti-neuroinflammatory, and anti-apoptotic effects. It is now being considered as a potential therapeutic agent for a wide variety of disorders, ranging from neoplasm to cardiovascular disease. More recent studies have shown that icariin exhibits potential preventive and/or therapeutic effects in the nervous system. For example, icariin can prevent the production of amyloid β (1-42) and inhibit the expression of amyloid precursor protein (APP) and β-site APP cleaving enzyme 1 (BACE-1) in animal models of Alzheimer's disease (AD). Icariin has been shown to mitigate pro-inflammatory responses of microglia in culture and in animal models of cerebral ischemia, depression, Parkinson's disease (PD), and multiple sclerosis (MS). Icariin also prevents the neurotoxicity induced by hydrogen peroxide (H₂O₂), endoplasmic reticulum (ER) stress, ibotenic acid, and homocysteine. In addition, icariin is implicated in facilitating learning and memory in both normal aging animals and disease models. To date, we still have no consolidated source of knowledge about the pharmacological effects of icariin in the nervous system, though its roles in other tissues have been reviewed in recent years. Here, we summarize the pharmacological development of icariin as well as its possible mechanisms in prevention and/or therapy of disorders afflicting the nervous system in hope of expanding the knowledge about the preventive and/or therapeutic effect of icariin in brain disorders.

Evaluation of selected traditional Chinese medical extracts for bone mineral density maintenance: A mechanistic study

Objective

To investigate the development of a minimal traditional Chinese medicine (TCM) formula using selected TCM ingredients and evaluating their biological activity with bone-specific in vitro tests. Finally, determining if the minimal formula can maintain bone mineral density (BMD) in a low bone mass (LBM)/osteoporosis (OP) model system.

Methods and results

Sixteen different TCM plant extracts were tested for estrogenic, osteogenic and osteoclastic activities. Despite robust activation of the full-length estrogen receptors α and β by Psoralea corylifolia and Epimedium brevicornu, these extracts do not activate the isolated estrogen ligand binding domains (LBD) of either ERα or ERβ; estrogen (17-β estradiol) fully activates the LBD of ERα and ERβ. E. brevicornu and Drynaria fortunei extracts activated cyclic AMP response elements (CRE) individually and when combined these ingredients stimulated the production of osteoblastic markers Runx2 and Bmp4 in MC3T3-E1 cells. E. brevicornu, Salvia miltiorrhiza, and Astragalus onobrychis extracts inhibited the Il-1β mediated activation of NF-κβ and an E. brevicornu/D. fortunei combination inhibited the development of osteoclasts from precursor cells. Further, a minimal formula containing the E. brevicornu/D. fortunei combination with or without a third ingredient (S. miltiorrhiza, Angelica sinensis, or Lycium barbarum) maintained bone mineral density (BMD) similar to an estradiol-treated control group in the ovariectomized rat; a model LBM/OP system.

Conclusion

A minimal formula consisting of TCM plant extracts that activate CRE and inhibit of NF-κβ activation, but do not behave like estrogen, maintain BMD in a LBM/OP model system.

Icariin modulates mitochondrial function and apoptosis in high glucose-induced glomerular podocytes through G protein-coupled estrogen receptors

Podocyte apoptosis in glomerular lesions has been found to have a dominant role in the progression of diabetic nephropathy. The present research aimed to explore the beneficial effect of icariin on diabetic podocytes by interfering in the process of apoptosis. Podocyte apoptosis was significantly exacerbated after high glucose treatment, with the level of reactive oxygen species (ROS) increasing simultaneously. Here, we demonstrated that icariin, which is a G protein-coupled estrogen receptor 1 (GPER) agonist, inhibited podocyte apoptosis by reducing ROS, maintaining the integrity of mitochondrial membranes. Moreover, the stabilization of mitochondria by icariin was reversed when GPER was knocked down in podocytes. Meanwhile, icariin inhibited the caspase cascade in podocyte apoptosis by promoting Bcl-2 expression and mitochondrial translocation. The above findings at least partly elucidated the mechanism by which icariin stabilized podocytes by inducing the mitochondrial Bcl-2 translocation and therefore preventing downstream apoptosis.

Ferulic Acid Rescues LPS-Induced Neurotoxicity via Modulation of the TLR4 Receptor in the Mouse Hippocampus

Microglia play a crucial role in the inflammatory brain response to infection. However, overactivation of microglia is neurotoxic. Toll-like receptor 4 (TLR4) is involved in microglial activation via lipopolysaccharide (LPS), which triggers a variety of cytotoxic pro-inflammatory markers that produce deleterious effects on neuronal cells. Ferulic acid (FA) is a phenolic compound that exerts antioxidant and anti-inflammatory effects in neurodegenerative disease. However, the manner in which FA inhibits neuroinflammation-induced neurodegeneration is poorly understood. Therefore, we investigated the anti-inflammatory effects of FA against LPS-induced neuroinflammation in the mouse brain. First, we provide evidence that FA interferes with TLR4 interaction sites, which are required for the activation of microglia-induced neuroinflammation, and further examined the potential mechanism of its neuroprotective effects in the mouse hippocampus using molecular docking simulation and immunoblot analysis. Our results indicated that FA treatment inhibited glial cell activation, p-JNK, p-NF_KB, and downstream signaling molecules, such as iNOS, COX-2, TNF-α, and IL-1β, in the mouse hippocampus and BV2 microglial cells. FA treatment strongly inhibited mitochondrial apoptotic signaling molecules, such as Bax, cytochrome C, caspase-3, and PARP-1, and reversed deregulated synaptic proteins, including PSD-95, synaptophysin, SNAP-25, and SNAP-23, and synaptic dysfunction in LPS-treated mice. These findings demonstrated that FA treatment interfered with the TLR4/MD2 complex binding site, which is crucial for evoking neuroinflammation via microglia activation and inhibited NF_KB likely via a JNK-dependent mechanism, which suggests a therapeutic implication for neuroinflammation-induced neurodegeneration.

Icariin prevents cytokine-induced β-cell death by inhibiting NF-κB signaling

The loss of insulin secretion in type I diabetes mellitus (T1DM) is caused by autoimmune-mediated destruction of insulin-producing pancreatic β-cells. Inflammatory cytokines and immune cell infiltration activate oxidative and endoplasmic reticulum (ER) stress, resulting in reduced β-cell viability. The current pharmacological agents used to control blood glucose have a limited effective duration and are accompanied by strong side effects. Blocking the inflammatory and immune responses that cause the β-cell damage has been investigated as a novel therapeutic approach to control T1DM. Icariin is a flavonoid component of Chinese medicinal herbs that has anti-inflammatory effects in vitro and in vivo. The results of the present study revealed that icariin abrogates the pro-apoptotic effect of inflammatory cytokines and significantly suppresses the activation of nuclear factor (NF)-κB in rat pancreatic β-cell lines. The present study may provide a basis for the potential use of icariin as a therapeutic agent for T1DM.

Hydrogen Sulfide Alleviates Lipopolysaccharide-Induced Diaphragm Dysfunction in Rats by Reducing Apoptosis and Inflammation through ROS/MAPK and TLR4/NF-κB Signaling Pathways

Diaphragm dysfunction is an important clinical problem worldwide. Hydrogen sulfide (H₂S) is involved in many physiological and pathological processes in mammals. However, the effect and mechanism of H₂S in diaphragm dysfunction have not been fully elucidated. In this study, we detected that the level of H₂S was decreased in lipopolysaccharide- (LPS-) treated L6 cells. Treatment with H₂S increased the proliferation and viability of LPS-treated L6 cells. We found that H₂S decreased reactive oxygen species- (ROS-) induced apoptosis through the mitogen-activated protein kinase (MAPK) signaling pathway in LPS-treated L6 cells. Administration of H₂S alleviated LPS-induced inflammation by mediating the toll-like receptor-4 (TLR-4)/nuclear factor-kappa B (NF-κB) signaling pathway in L6 cells. Furthermore, H₂S improved diaphragmatic function and structure through the reduction of inflammation and apoptosis in the diaphragm of septic rats. In conclusion, these findings indicate that H₂S ameliorates LPS-induced diaphragm dysfunction in rats by reducing apoptosis and inflammation through ROS/MAPK and TLR4/NF-κB signaling pathways. Novel slow-releasing H₂S donors can be designed and applied for the treatment of diaphragm dysfunction.

Icariin promotes osteoblastic differentiation in OVX mice via MAPK signaling pathway revealed by profiling

Objective: Icariin (ICA), an extract from epimedium, has been reported to be effective in promoting bone formation. The objective of the study is to search for the molecular targets of ICA in bone mesenchymal stem cells (bMSCs) from the mice with ovariectomy (OVX)-induced osteoporosis.

Methods: Six-month-old Imprinting Control Region (ICR) mice that underwent OVX were treated with ICA. After three months, bone mass was evaluated by microcomputed tomography, morphometry and immunohistological detection. bMSCs were isolated from the femur and tibia to observe the self-renewal and differentiation capacities using colony-forming unit fibroblastic (CFU-F), colony-forming unit adipocyte (CFU-Adipo) and alkaline phosphatase (ALP) staining. In addition, microarray of bMSCs ex vivo was measured two weeks after ICA treatment and analyzed by heatmap and pathway analysis. The signaling pathway was further explored by western blot assay and inhibitors of p38 and ERK: SB203508 and PD98059.

Results: [Formula: see text]CT displayed a decrease in bone mass for three months after OVX. ICA treatment increased the trabecular thickness (Tb.Th), osteoblast number while decreased osteoclast number, elevating osteocalcin (OC) protein levels in vivo and facilitating the self-renewal and osteoblastic differentiation of bMSCs ex vivo. Microarray data indicated ICA rescued several gene expressions that were dysregulated by OVX. Pathway analysis revealed that the core genes acted by ICA were highly involved in MAPK signaling pathway. Further study demonstrated ICA suppressed ERK while stimulated p38 phosphorylation to promote osteoblastic differentiation in vitro.

Conclusion: ICA promotes osteoblastic differentiation of bMSCs in OVX mice. MAPK signaling pathway might be involved in the process.

Protective effects of icariin on human vascular endothelial cells induced by oxidized low-density lipoprotein via modulating caspase-3 and Bcl-2

Icariin belongs to the family of flavonoids that is extracted from Epimedium brevicornum Maxim, and exhibits antioxidative, antitumorigenic, antiosteoporotic, immunoregulatory and antiatherosclerotic properties. To understand the mechanisms underlying the antiatherosclerotic properties of icariin, the present study investigated the effects of icariin on human vascular endothelial cells (HUVECs) following treatment with oxidized low‑density lipoprotein (ox‑LDL). Thus, following pretreatment with icariin at four various concentrations (0, 10, 20 and 40 µM), HUVECs were stimulated with ox‑LDL (100 µg/ml). The viability of cells was evaluated via an MTT assay and flow cytometry was performed to assess apoptosis. Additionally, the protein and mRNA expression levels of apoptosis regulator Bcl‑2 (Bcl‑2) and caspase‑3 were determined by western blotting and reverse transcription‑quantitative polymerase chain reaction. The findings of the present study indicated that icariin prevented injury and apoptosis in HUVECs following ox‑LDL treatment, in particular via the regulation of protein and mRNA expression levels of Bcl-2 and caspase-3.