Kinsenoside Ameliorates Oxidative Stress-Induced RPE Cell Apoptosis and Inhibits Angiogenesis via Erk/p38/NF-κB/VEGF Signaling

Current advances on the phytochemistry, pharmacology, quality control and applications of Anoectochilus roxburghii

Anoectochilus roxburghii (Wall.) Lindl. (AR) is a perennial herb that has long been used as medicinal and edible plant. In Traditional Chinese Medicine (TCM), AR is utilized to treat various diseases including hyperuricemia, type 2 diabetes mellitus, cancers and inflammatory diseases. Recent advances in the discovery and isolation of bio-active compounds have unveils the main medicinal ingredients, such as quercetin, kinsenoside and rhamnazin. Pharmacological studies further demonstrated its activities, containing anti-inflammation, anti-oxidation, and antihyperlipidemia effects. The processed AR products have various commercial applications in functional foods and cosmetics. AR has been used to prepare soup, drinkbeverage, jelly, face masks, soap, etc. However, despite the abundant medicinal value, it hasn't been included in the 2020 Chinese Pharmacopoeia up to now. There is also no consistent evaluation standard across provinces. This seriously affects the safety and the efficacy of TCM prescriptions, not to mention the development question. This review summarizes recent research on AR in phytochemistry, pharmacology, quality control and applications, raises the corresponding solutions to provide references and potential directions for further studies.

The impact of NF-κB on inflammatory and angiogenic processes in age-related macular degeneration

Age-related macular degeneration (AMD) is a prominent cause of vision loss, characterized by two different types, dry (atrophic) and wet (neovascular). Dry AMD is distinguished by the progressive deterioration of retinal cells, which ultimately causes a decline in vision. In contrast, wet AMD is defined by the abnormal development of blood vessels underneath the retina, leading to a sudden and severe vision impairment. The course of AMD is primarily driven by chronic inflammation and pathological angiogenesis, in which the NF-κB signaling pathway plays a crucial role. The activation of NF-κB results in the generation of pro-inflammatory cytokines, chemokines, and angiogenic factors like VEGF, which contribute to inflammation and the formation of new blood vessels in AMD. This review analyzes the intricate relationship between NF-κB signaling, inflammation, and angiogenesis in AMD and assesses the possibility of using NF-κB as a target for therapy. The evaluation involves a comprehensive examination of preclinical and clinical evidence that substantiates the effectiveness of NF-κB inhibitors in treating AMD by diminishing inflammation and pathological angiogenesis.

Lemon Peel Water Extract: A Novel Material for Retinal Health, Protecting Retinal Pigment Epithelial Cells against Dynamin-Related Protein 1-Mediated Mitochondrial Fission by Blocking ROS-Stimulated Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Pathway

Previous studies showed that NaIO3 can induce oxidative stress-mediated retinal pigment epithelium (RPE) damage to simulate age-related macular degeneration (AMD). Lemon peel is rich in antioxidants and components that can penetrate the blood-retinal barrier, but their role in retinal oxidative damage remains unexplored. Here, we explore the protection of lemon peel ultrasonic-assisted water extract (LUWE), containing large amounts of flavonoids and polyphenols, against NaIO3-induced retinal degeneration. We initially demonstrated that LUWE, orally administered, prevented retinal distortion and thinning on the inner and outer nuclei layers, downregulating cleaved caspase-3 protein expression in RPE cells in NaIO3-induced mice. The effect of LUWE was achieved through the suppression of apoptosis and the associated proteins, such as cleaved PARP and cleaved caspase-3, as suggested by NaIO3-induced ARPE-19 cell models. This is because LUWE reduced reactive oxygen species-mediated mitochondrial fission via regulating p-Drp-1 and Fis1 expression. We further confirmed that LUWE suppresses the expression of p-MEK-1/2 and p-ERK-1/2 in NaIO3-induced ARPE-19 cells, thereby providing the protection described above, which was confirmed using PD98059 and U0126. These results indicated that LUWE prevents mitochondrial oxidative stress-mediated RPE damage via the MEK/ERK pathway. Elucidation of the molecular mechanism may provide a new protective strategy against retinal degeneration.

Integrated network pharmacology and experimental validation to explore the potential pharmacological mechanism of Qihuang Granule and its main ingredients in regulating ferroptosis in AMD

BACKGROUND

Qihuang Granule (QHG) is a traditional prescription  that has exhibited potential in safeguarding against age-related maculopathy (AMD). Salvia miltiorrhiza (SM) and Fructus lycii (FL) are the main components of QHG. Ferroptosis, a newly discovered, iron-dependent, regulated cell death pathway, have been implicated in the pathogenesis of AMD. This study delves into the intricate mechanism by which SM/FL and QHG confer protection against AMD by modulating the ferroptosis pathway, employing a combination of network pharmacology and experimental validation.

METHODS

Bioactive compounds and potential targets of SM and FL were gathered from databases such as TCMSP, GeneCard, OMIM, and FerrDb, along with AMD-related genes and key genes responsible for ferroptosis regulation. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein-protein interaction (PPI) network were performed to discover the potential mechanism. The construction of an interaction network involving AMD, ferroptosis, SM/FL potential target genes was facilitated by the STRING database and realized using Cytoscape software. Subsequent validation was accomplished through molecular docking and in vitro cell experiments.

RESULTS

Noteworthy active compounds including quercetin, tanshinone IIA, luteolin, cryptotanshinone, and hub targets such as HIF-1α, EGFR, IL6, and VEGFA were identified. KEGG enrichment unveiled the HIF-1 signalling pathway as profoundly enriched, and IL6 and VEGF were involved. The molecular docking revealed the significant active compounds with hub genes and quercetin showed good binding to HIF-1α, which is involved in inflammation and angiogenesis. Experimental results verified that both herbs and QHG could regulate key ferroptosis-related targets in the retinal pigment epithelium and inhibit the expression of HIF-1α, VEGFA, and IL-6, subsequently increase cell viability and decrease the ROS content induced by H2O2.

CONCLUSION

This study demonstrates the molecular mechanism through which SM/FL and QHG protect against AMD and emerges as a plausible mechanism underlying this protection.

MAPK Pathways in Ocular Pathophysiology: Potential Therapeutic Drugs and Challenges

Mitogen-activated protein kinase (MAPK) pathways represent ubiquitous cellular signal transduction pathways that regulate all aspects of life and are frequently altered in disease. Once activated through phosphorylation, these MAPKs in turn phosphorylate and activate transcription factors present either in the cytoplasm or in the nucleus, leading to the expression of target genes and, as a consequence, they elicit various biological responses. The aim of this work is to provide a comprehensive review focusing on the roles of MAPK signaling pathways in ocular pathophysiology and the potential to influence these for the treatment of eye diseases. We summarize the current knowledge of identified MAPK-targeting compounds in the context of ocular diseases such as macular degeneration, cataract, glaucoma and keratopathy, but also in rare ocular diseases where the cell differentiation, proliferation or migration are defective. Potential therapeutic interventions are also discussed. Additionally, we discuss challenges in overcoming the reported eye toxicity of some MAPK inhibitors.

Safety of intraocular anti-VEGF antibody treatment under in vitro HTLV-1 infection

Introduction

HTLV-1 (human T-cell lymphotropic virus type 1) is a retrovirus that infects approximately 20 million people worldwide. Many diseases are caused by this virus, including HTLV-1-associated myelopathy, adult T-cell leukemia, and HTLV-1 uveitis. Intraocular anti-vascular endothelial growth factor (VEGF) antibody injection has been widely used in ophthalmology, and it is reportedly effective against age-related macular degeneration, complications of diabetic retinopathy, and retinal vein occlusions. HTLV-1 mimics VEGF₁₆₅, the predominant isoform of VEGF, to recruit neuropilin-1 and heparan sulfate proteoglycans. VEGF₁₆₅ is also a selective competitor of HTLV-1 entry. Here, we investigated the effects of an anti-VEGF antibody on ocular status under conditions of HTLV-1 infection in vitro.

Methods

We used MT2 and TL-Om1 cells as HTLV-1-infected cells and Jurkat cells as controls. Primary human retinal pigment epithelial cells (HRPEpiCs) and ARPE19 HRPEpiCs were used as ocular cells; MT2/TL-Om1/Jurkat cells and HRPEpiCs/ARPE19 cells were co-cultured to simulate the intraocular environment of HTLV-1-infected patients. Aflibercept was administered as an anti-VEGF antibody. To avoid possible T-cell adhesion, we lethally irradiated MT2/TL-Om1/Jurkat cells prior to the experiments.

Results

Anti-VEGF antibody treatment had no effect on activated NF-κB production, inflammatory cytokines, chemokines, HTLV-1 proviral load (PVL), or cell counts in the retinal pigment epithelium (RPE) under MT2 co-culture conditions. Under TL-Om1 co-culture conditions, anti-VEGF antibody treatment did not affect the production of activated NF-κB, chemokines, PVL, or cell counts, but production of the inflammatory cytokine IL-6 was increased. In addition, anti-VEGF treatment did not affect PVL in HTLV-1-infected T cells.

Conclusion

This preliminary in vitro assessment indicates that intraocular anti-VEGF antibody treatment for HTLV-1 infection does not exacerbate HTLV-1-related inflammation and thus may be safe for use.

Injectable Anti-Inflammatory Supramolecular Nanofiber Hydrogel to Promote Anti-VEGF Therapy in Age-Related Macular Degeneration Treatment

Age-related macular degeneration (AMD) is a major cause of visual impairment and severe vision loss worldwide, while the currently available treatments are often unsatisfactory. Previous studies have demonstrated both inflammation and oxidative-stress-induced damage to the retinal pigment epithelium are involved in the pathogenesis of aberrant development of blood vessels in wet AMD (wet-AMD). Although antivascular endothelial growth factor (VEGF) therapy (e.g., Ranibizumab) can impair the growth of new blood vessels, side effects are still found with repeated monthly intravitreal injections. Here, an injectable antibody-loaded supramolecular nanofiber hydrogel is fabricated by simply mixing betamethasone phosphate (BetP), a clinic anti-inflammatory drug, anti-VEGF, the gold-standard anti-VEGF drug for AMD treatment, with CaCl₂ . Upon intravitreal injection, such BetP-based hydrogel (BetP-Gel), while enabling long-term sustained release of anti-VEGF to inhibit vascular proliferation in the retina and attenuate choroidal neovascularization, can also scavenge reactive oxygen species to reduce local inflammation. Remarkably, such BetP-Gel can dramatically prolong the effective treatment time of conventional anti-VEGF therapy. Notably, anti-VEGF-loaded supramolecular hydrogel based on all clinically approved agents may be readily translated into clinical use for AMD treatment, with the potential to replace the current anti-VEGF therapy.

Advances in the therapeutic application and pharmacological properties of kinsenoside against inflammation and oxidative stress-induced disorders

Extensive research has implicated inflammation and oxidative stress in the development of multiple diseases, such as diabetes, hepatitis, and arthritis. Kinsenoside (KD), a bioactive glycoside component extracted from the medicinal plant Anoectochilus roxburghii, has been shown to exhibit potent anti-inflammatory and anti-oxidative abilities. In this review, we summarize multiple effects of KD, including hepatoprotection, pro-osteogenesis, anti-hyperglycemia, vascular protection, immune regulation, vision protection, and infection inhibition, which are partly responsible for suppressing inflammation signaling and oxidative stress. The protective action of KD against dysfunctional lipid metabolism is also associated with limiting inflammatory signals, due to the crosstalk between inflammation and lipid metabolism. Ferroptosis, a process involved in both inflammation and oxidative damage, is potentially regulated by KD. In addition, we discuss the physicochemical properties and pharmacokinetic profiles of KD. Advances in cultivation and artificial synthesis techniques are promising evidence that the shortage in raw materials required for KD production can be overcome. In addition, novel drug delivery systems can improve the in vivo rapid clearance and poor bioavailability of KD. In this integrated review, we aim to offer novel insights into the molecular mechanisms underlying the therapeutic role of KD and lay solid foundations for the utilization of KD in clinical practice.

Mitochondrial Dysfunction in Oxidative Stress-Mediated Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) is the most common contributor to low back pain (LBP). Recent studies have found that oxidative stress and reactive oxygen species (ROS) play an important role in IVDD. As a by‐product of aerobic respiration, ROS is mainly produced in the mitochondria by the electron transport chain and other mitochondrial located proteins. With the excessive accumulation of ROS, mitochondria are also the primary target of ROS attack in disc cells. A disrupted balance between intracellular ROS production and antioxidant capacity will lead to oxidative stress, which is the key contributor to cell apoptosis, cell senescence, excessive autophagy, and mitochondrial dysfunction. As the pivotal ingredient of oxidative stress, mitochondrial dysfunction manifests as imbalanced mitochondrial dynamics and dysregulated mitophagy. Mitochondria can alter their own dynamics through the process of fusion and fission, so that disabled mitochondria can be separated from the mitochondrial pool. Moreover, mitophagy participates by clearing these dysfunctional mitochondria. Abnormality in any of these processes either increases the production or decreases the clearance of ROS, leading to a vicious cycle that results in the death of intervertebral disc cells in large quantities, combined with degradation of the extracellular matrix and overproduction of matrix metalloproteinase. In this review, we explain the changes in mitochondrial morphology and function during oxidative stress‐mediated IVDD and highlight the important role of mitochondria in this process. Eventually, we summarize the IVDD therapeutic strategies targeting mitochondrial dysfunction based on current understanding of the role of oxidative stress in IVDD.

Therapeutic effect and mechanism of polysaccharides from Anoectochilus Roxburghii (Wall.) Lindl. in diet-induced obesity

BACKGROUND

Recent studies have shown that polysaccharides from Anoectochilus roxburghii (Wall.) Lindl. (ARPs) can reduce blood glucose levels, ameliorate oxidative stress and inflammation. However, whether ARPs have a beneficial effect on diet-induced obesity remain to be determined.

PURPOSE

This study aims to investigate the effect and mechanism of ARPs in improving obesity and metabolic disorders induced by high-fat diet (HFD).

METHODS

In this study, 6-week-old male mice were fed with HFD or chow diet for 13 weeks, and a dietary supplementation with ARPs was carried out. Glucose tolerance test and insulin tolerance test were performed to measure the glucose tolerance and insulin sensitivity. Adipose tissue and liver were isolated for analysis by qRT-PCR, Western blotting, hematoxylin-eosin staining and immunostaining.

RESULTS

At week 13, body weight and fat mass were significantly increased by HFD, but ARPs supplementation abolished these phenotypes. Compared with HFD group, thermogenic genes including Ucp-1, Pgc-1α, Prdm16 and Dio2 in adipose tissue were up-regulated in ARPs-treated mice. In addition, ARPs decreased liver lipid accumulation by reducing lipid synthesis and increasing oxidation. Meanwhile, dyslipidemia and insulin resistance induced by HFD were improved by ARPs. Mechanistically, ARPs can promote fat thermogenesis via AMPK/SIRT1/PGC-1α signaling pathway.

CONCLUSION

Dietary supplementation of ARPs can protect mice against diet-induced obesity, fatty liver and insulin resistance. Our study reveals a potential therapeutic effect for ARPs in regulating energy homeostasis.

The Activation of AMPK/NRF2 Pathway in Lung Epithelial Cells Is Involved in the Protective Effects of Kinsenoside on Lipopolysaccharide-Induced Acute Lung Injury

The disorder of mitochondrial dynamic equilibrium of lung epithelial cell is one of the critical causes of acute lung injury (ALI). Kinsenoside (Kin) serves as an active small-molecule component derived from traditional medicinal herb displaying multiple pharmacological actions in cancers, hyperglycemia, and liver disease. The objective of this study was to investigate the effects of Kin on lipopolysaccharide- (LPS-) induced ALI and further explore possible molecular mechanisms. Kin was administered orally (100 mg/kg/day) for 7 consecutive days before LPS instillation (5 mg/kg). After 12 hours, pathological injury, inflammatory response, and oxidative stress were detected. The results demonstrated that Kin significantly alleviated lung pathological injury and decreased the infiltration of inflammatory cells and the release of inflammatory mediators in bronchoalveolar lavage fluid (BALF), apart from inhibiting the production of reactive oxygen species (ROS) and lipid peroxidation. Meanwhile, Kin also promoted mitochondrial fusion and restrained mitochondrial fission in mice with ALI. In terms of mechanism, Kin pretreatment increased the phosphorylation of AMP-activated protein kinase (AMPK) and the protein level of nuclear factor erythroid 2-related factor 2 (NRF2). In Ampk-α knockout mice challenged with LPS, Kin lost its pulmonary protective effects, accompanied by lower NRF2 level. In vitro experiments further unveiled that either AMPK inhibition by Compound C or NRF2 knockdown by siRNA abolished the protective roles of Kin in LPS-treated A549 lung epithelial cells. And NRF2 activator TAT-14 could reverse the effects of Ampk-α deficiency. In conclusion, Kin possesses the ability to prevent LPS-induced ALI by modulating mitochondrial dynamic equilibrium in lung epithelial cell in an AMPK/NRF2-dependent manner.

Kinsenoside attenuates liver fibro-inflammation by suppressing dendritic cells via the PI3K-AKT-FoxO1 pathway

Kinsenoside (KD) exhibits anti-inflammatory and immunosuppressive effects. Dendritic cells (DCs) are critical regulators of the pathologic inflammatory milieu in liver fibrosis (LF). Herein, we explored whether and how KD repressed development of LF via DC regulation and verified the pathway involved in the process. Given our analysis, both KD and adoptive transfer of KD-conditioned DCs conspicuously reduced hepatic histopathological damage, proinflammatory cytokine release and extracellular matrix deposition in CCl₄-induced LF mice. Of note, KD restrained the LF-driven rise in CD86, MHC-II, and CCR7 levels and, simultaneously, upregulated PD-L1 expression on DCs specifically, which blocked CD8⁺T cell activation. Additionally, KD reduced DC glycolysis, maintained DCs immature, accompanied by IL-12 decrease in DCs. Inhibiting DC function by KD disturbed the communication of DCs and HSCs with the expression or secretion of α-SMA and Col-I declined in the liver. Mechanistically, KD suppressed the phosphorylation of PI3K-AKT driven by LF or PI3K agonist, followed by enhanced nuclear transport of FoxO1 and upregulated interaction of FoxO1 with the PD-L1 promoter in DCs. PI3K inhibitor or si-IL-12 acting on DC could relieve LF, HSC activation and diminish the effect of KD. In conclusion, KD suppressed DC maturation with promoted PD-L1 expression via PI3K-AKT-FoxO1 and decreased IL-12 secretion, which blocked activation of CD8⁺T cells and HSCs, thereby alleviating liver injury and fibro-inflammation in LF.

Discovering the Potential of Natural Antioxidants in Age-Related Macular Degeneration: A Review

Age-related macular degeneration (AMD) is a multifactorial disease associated with anatomical changes in the inner retina. Despite tremendous advances in clinical care, there is currently no cure for AMD. This review aims to evaluate the published literature on the therapeutic roles of natural antioxidants in AMD. A literature search of PubMed, Web of Science and Google Scholar for peer-reviewed articles published between 1 January 2011 and 31 October 2021 was undertaken. A total of 82 preclinical and 18 clinical studies were eligible for inclusion in this review. We identified active compounds, carotenoids, extracts and polysaccharides, flavonoids, formulations, vitamins and whole foods with potential therapeutic roles in AMD. We evaluated the integral cellular signaling pathways including the activation of antioxidant pathways and angiogenesis pathways orchestrating their mode of action. In conclusion, we examined the therapeutic roles of natural antioxidants in AMD which warrant further study for application in clinical practice. Our current understanding is that natural antioxidants have the potential to improve or halt the progression of AMD, and tailoring therapeutics to the specific disease stages may be the key to preventing irreversible vision loss.

Kinsenoside Alleviates 17α-Ethinylestradiol-Induced Cholestatic Liver Injury in Rats by Inhibiting Inflammatory Responses and Regulating FXR-Mediated Bile Acid Homeostasis

Cholestasis is an important predisposing factor of liver diseases, such as hepatocyte necrosis, liver fibrosis and primary biliary cirrhosis. In this study, we aimed to investigate the effects of Kinsenoside (KD), a natural active ingredient of Anoectochilus roxburghii, on estrogen-induced cholestatic liver injury in Sprague-Dawley rats and the underlying mechanism. The rats were randomly divided into six groups: control group, model group, low-dose KD group (50 mg/kg body weight, KD-L), medium-dose KD group (100 mg/kg body weight, KD-M), high-dose KD group (200 mg/kg body weight, KD-H) and ursodeoxycholic acid group (40 mg/kg body weight, UDCA). 17α-Ethinylestradiol (EE) was used to establish an experimental animal model of estrogen-induced cholestasis (EIC). The results demonstrated that KD alleviated liver pathologic damage, serum biochemical status and inhibited hepatocellular microstructure disorder and bile duct hyperplasia in EE-induced cholestatic rats. Mechanically, KD alleviated EE-induced cholestatic liver injury by inhibiting inflammatory responses and regulating bile acid homeostasis. Concretely, KD reduced the expression of IL-1β and IL-6 by inhibiting NF-κB p65 to suppress EE-mediated inflammation in rat liver. KD enhanced the expression of FXR and inhibited EE-mediated reduction of FXR in vitro and in vivo. It was the potential mechanism that KD mitigates cholestasis by increasing efflux and inhibiting uptake of bile acids via FXR-mediated induction of bile salt export pump (BSEP) and reduction of Na⁺-dependent taurocholate cotransport peptide (NTCP) to maintain bile acid homeostasis. Moreover, KD repressed the bile acid synthesis through reducing the expression of synthetic enzyme (CYP7A1), thereby normalizing the expression of metabolic enzyme (SULT2A1) of bile acid. In conclusion, our results revealed that KD may be an effective drug candidate for the treatment of cholestasis.

Histamine causes an imbalance between pro-angiogenic and anti-angiogenic factors in the retinal pigment epithelium of diabetic retina via H4 receptor/p38 MAPK axis

INTRODUCTION

Systemic histaminergic activity is elevated in patients with diabetes mellitus. There are a few studies suggesting that histamine is implicated in the pathogenesis of diabetes, but the exact role of histamine in the development of diabetic retinopathy is unclear. The aim of this study was to investigate the role of histamine receptor H4 (HRH4) in the regulation of retinal pigment epithelium (RPE)-derived pro-angiogenic and anti-angiogenic factors under diabetic conditions.

RESEARCH DESIGN AND METHODS

The levels of vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), histamine and histidine decarboxylase (HDC) in the serum and vitreous samples of patients with diabetes were compared with those of patients without diabetes. The effect of hyperglycemia on expression levels of HRH4, VEGF, IL-6 and pigment epithelium-derived factor (PEDF) in the RPE was determined. The role of HRH4 in high glucose-induced regulation of VEGF, IL-6 and PEDF in ARPE-19 cells and the underlying regulatory mechanism were verified using an RNA interference-mediated knockdown study.

RESULTS

The serum and vitreous levels of VEGF, IL-6, histamine and HDC were more increased in patients with diabetic retinopathy than in patients without diabetes. HRH4 was overexpressed in RPE both in vitro and in vivo. Histamine treatment upregulated VEGF and IL-6 and downregulated PEDF expression in ARPE-19 cells cultivated under hyperglycemic conditions. Hyperglycemia-induced phosphorylation of p38 and subsequent upregulation of VEGF and IL-6 and downregulation of PEDF were dampened by small interfering RNA-mediated knockdown of HRH4 in ARPE-19 cells.

CONCLUSIONS

Taken together, HRH4 was a critical regulator of VEGF, IL-6 and PEDF in the RPE under hyperglycemic conditions and the p38 mitogen-activated protein kinase pathway mediated this regulatory mechanism.

Not All Stressors Are Equal: Mechanism of Stressors on RPE Cell Degeneration

Age-related macular degeneration (AMD) is a major cause of irreversible blindness among the elderly population. Dysfunction and degeneration of the retinal pigment epithelial (RPE) layer in the retina underscore the pathogenesis of both dry and wet AMD. Advanced age, cigarette smoke and genetic factors have been found to be the prominent risk factors for AMD, which point to an important role for oxidative stress and aging in AMD pathogenesis. However, the mechanisms whereby oxidative stress and aging lead to RPE cell degeneration are still unclear. As cell senescence and cell death are the major outcomes from oxidative stress and aging, here we review the mechanisms of RPE cell senescence and different kinds of cell death, including apoptosis, necroptosis, pyroptosis, ferroptosis, with an aim to clarify how RPE cell degeneration could occur in response to AMD-related stresses, including H₂O₂, 4-Hydroxynonenal (4-HNE), N-retinylidene-N-retinyl-ethanolamine (A2E), Alu RNA and amyloid β (Aβ). Besides those, sodium iodate (NaIO₃) induced RPE cell degeneration is also discussed in this review. Although NaIO₃ itself is not related to AMD, this line of study would help understand the mechanism of RPE degeneration.

Steroid 5α-Reductase Type I Induces Cell Viability and Migration via Nuclear Factor-κB/Vascular Endothelial Growth Factor Signaling Pathway in Colorectal Cancer

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Steroid 5α-reductase type I (SRD5A1), as an important part of the steroid metabolism, converts testosterone to dihydrotestosterone and regulates sex hormone levels, which accommodates tumor occurrence or development. However, the underlying molecular mechanism of SRD5A1 in CRC remains unclear. We compared SRD5A1 expression in CRC tissues with normal controls by immunohistochemistry and found that elevated SRD5A1 in CRC was relevant for poor patient prognosis. Furthermore, inducible downregulation of SRD5A1 by small hairpin RNA reduced cell viability, promoted cell cycle arrest, and induced cell apoptosis and cellular senescence of CRC cells, as well as attenuated cell migration ability. In the following experiments, we used dutasteride (an inhibitor of SRD5A1/2) to explore its inhibitory effect on the biological processes of CRC cells, as mentioned earlier. Further mechanism study demonstrated that the repression of SRD5A1 abolished the expression of p65 and vascular endothelial growth factor, suggesting that SRD5A1 might regulate cell viability and migration through nuclear factor-κB/vascular endothelial growth factor signaling pathway. Collectively, these findings implicate SRD5A1 acting as a novel biomarker for CRC diagnosis and prognosis and provide compelling evidence for the future evaluation of dutasteride as a promising candidate for CRC treatment.

Stepwise rapid tracking strategy to identify active molecules from Ixeris sonchifolia Hance based on "'affinity mass spectrometry-atomic force microscopy imaging'" technology

In this study, a novel stepwise rapid tracking strategy was reported to identify the active molecules from Ixeris sonchifolia Hance (IsH) in the treatment of coronary heart disease (CHD) based on "affinity mass spectrometry (MS)-atomic force microscopy (AFM) imaging" technology. First, vascular endothelial growth factor receptor 2 (VEGFR2) of the vascular endothelial growth factor (VEGF) signal transduction pathway located on the cell membrane was revealed to be the core target protein in CHD treatment through network pharmacology and bioinformatics. In addition, affinity MS screening based on VEGFR2 identified isochlorogenic acid A and luteolin-7-O-glucuronide as having stronger affinity with VEGFR2. Then, the active molecule was elucidated based on the observation that its actions accompanied the molecular morphological changes by AFM imaging and it could act on the binding pocket of VEGFR2 through molecular docking which further demonstrated the analysis and inference of AFM imaging. The methyl thiazolyl tetrazolium (MTT) assay finally confirmed that the active molecules specifically combined with the potential core target protein to protect the viability of cardiomyocytes, which identified the main potential active molecules in IsH for the treatment of CHD and provided a possible mechanism for the protective role of the drug. The technology established in this study could facilitate the rapid tracing of potential active molecules in traditional Chinese medicine (TCM), which would provide further a reference for research on quality, molecular mechanisms and new drugs.

Optimization of Ultrasound Assisted Extraction (UAE) of Kinsenoside Compound from Anoectochilus roxburghii (Wall.) Lindl by Response Surface Methodology (RSM)

The purpose of this study was to establish an extraction method for the kinsenoside compound from the whole plant Anoectochilus roxburghii. Ultrasound assisted extraction (UAE) and Ultra-high performance liquid chromatography (UPLC) method were used to extract and determine the content of kinsenoside, while response surface method (RSM) was used to optimize the extraction process. The best possible range for methanol concentration (0–100%), the liquid-solid ratio (5:1–30:1 mL/g), ultrasonic power (240–540 W), duration of ultrasound (10–50 min), ultrasonic temperature (10–60 °C), and the number of extractions (1–4) were obtained according to the single factor experiments. Then, using the Box-Behnken design (BBD) of response surface analysis, the optimum extraction conditions were obtained with 16.33% methanol concentration, the liquid-solid ratio of 10.83:1 mL/g and 35.00 °C ultrasonic temperature. Under these conditions, kinsenoside extraction yield reached 32.24% dry weight. The best conditions were applied to determine the kinsenoside content in seven different cultivation ages in Anoectochilus roxburghii.

Protective effect of rhodioloside and bone marrow mesenchymal stem cells infected with HIF-1-expressing adenovirus on acute spinal cord injury

Rhodioloside has been shown to protect cells from hypoxia injury, and bone marrow mesenchymal stem cells have a good effect on tissue repair. To study the effects of rhodioloside and bone marrow mesenchymal stem cells on spinal cord injury, a rat model of spinal cord injury was established using the Infinite Horizons method. After establishing the model, the rats were randomly divided into five groups. Rats in the control group were intragastrically injected with phosphate buffered saline (PBS) (5 μL). PBS was injected at 6 equidistant points around 5 mm from the injury site and at a depth of 5 mm. Rats in the rhodioloside group were intragastrically injected with rhodioloside (5 g/kg) and intramuscularly injected with PBS. Rats in the mesenchymal stem cell (MSC) group were intramuscularly injected with PBS and intramuscularly with MSCs (8 × 10⁶/mL in a 50-μL cell suspension). Rats in the Ad-HIF-MSC group were intragastrically injected with PBS and intramuscularly injected with HIF-1 adenovirus-infected MSCs. Rats in the rhodioloside + Ad-HIF-MSC group were intramuscularly injected with MSCs infected with the HIF-1 adenovirus and intragastrically injected with rhodioloside. One week after treatment, exercise recovery was evaluated with a modified combined behavioral score scale. Hematoxylin-eosin staining and Pischingert’s methylene blue staining were used to detect any histological or pathological changes in spinal cord tissue. Levels of adenovirus IX and Sry mRNA were detected by real-time quantitative polymerase chain reaction and used to determine the number of adenovirus and mesenchymal stem cells that were transfected into the spinal cord. Immunohistochemical staining was applied to detect HIF-1 protein levels in the spinal cord. The results showed that: (1) compared with the other groups, the rhodioloside + Ad-HIF-MSC group exhibited the highest combined behavioral score (P < 0.05), the most recovered tissue, and the greatest number of neurons, as indicated by Pischingert’s methylene blue staining. (2) Compared with the PBS group, HIF-1 protein expression was greater in the rhodioloside group (P < 0.05). (3) Compared with the Ad-HIF-MSC group, Sry mRNA levels were higher in the rhodioloside + Ad-HIF-MSC group (P < 0.05). These results confirm that rhodioloside combined with bone marrow mesenchymal stem cells can promote the recovery of spinal cord injury and activate the HIF-1 pathway to promote the survival of bone marrow mesenchymal stem cells and repair damaged neurons within spinal cord tissue. This experiment was approved by the Animal Ethics Committee of Gansu University of Traditional Chinese Medicine, China (approval No. 2015KYLL029) in June 2015.

Kinsenoside ameliorates intervertebral disc degeneration through the activation of AKT-ERK1/2-Nrf2 signaling pathway

Intervertebral disc degeneration (IDD) is recognized as the major contributor to low back pain, which results in disability worldwide and heavy burdens on society and economy. Here we present evidence that the lower level of Nrf2 is closely associated with higher grade of IDD. The apoptosis and senescence of nucleus pulposus cells (NPCs) were exacerbated by Nrf2 knockdown, but suppressed by Nrf2 overexpression under oxidative stress. Based on findings that Kinsenoside could exert multiple pharmacological effects, we found that Kinsenoside rescued the NPC viability under oxidative stress and protected against apoptosis, senescence and mitochondrial dysfunction in a Nrf2-dependent way. Further experiments revealed that Kinsenoside activated a signaling pathway of AKT-ERK1/2-Nrf2 in NPCs. Moreover, in vivo study showed that Kinsenoside ameliorated IDD in a puncture-induced model. Together, the present work suggests that Nrf2 is involved in the pathogenesis of IDD and shows the protective effects as well as the underlying mechanism of Kinsenoside on Nrf2 activation in NPCs.

Rubidium Chloride Targets Jnk/p38-Mediated NF-κB Activation to Attenuate Osteoclastogenesis and Facilitate Osteoblastogenesis

The unbalanced crosstalk between osteoclasts and osteoblasts could lead to disruptive bone homeostasis. Herein, we investigated the therapeutic effects of rubidium chloride (RbCl) on ovariectomized (OVX) and titanium (Ti) particle-induced calvaria osteolysis mouse models, showing that non-toxic RbCl attenuated RANKL-stimulated osteoclast formation and functionality while significantly enhancing osteogenesis in vitro. The expressions of osteoclast-specific genes were downregulated considerably by RbCl. Despite the direct inhibition of RANKL-induced activation of MAPK signaling, RbCl was able to target NF-κB directly and indirectly. We found that after the co-stimulation of the c-Jun N-terminal kinase (Jnk)/p38 activator and RANKL, RbCl inhibited the elevated expression of p-IKKα and the degradation of IκBα in osteoclast precursors, indicating indirect NF-κB inhibition via MAPK suppression. Furthermore, the two animal models demonstrated that RbCl attenuated tartrate-resistant acid phosphate (TRAP)-positive osteoclastogenesis and rescued bone loss caused by the hormonal dysfunction and wear particle in vivo. Altogether, these findings suggest that RbCl can target Jnk/p38-mediated NF-κB activation to attenuate osteoclastogenesis, while facilitating osteoblastogenesis both in vivo and in vitro, suggesting the possible future use of RbCl for surface coating of orthopedic implant biomaterials to protect against osteoporosis.

ID2 protects retinal pigment epithelium cells from oxidative damage through p-ERK1/2/ID2/NRF2

Age-related macular degeneration (AMD) is the leading cause of blindness during aging. The degeneration of retinal pigment epithelium (RPE) is the main pathologic characteristic of AMD. ID2 is a member of the Inhibitor of DNA binding proteins (ID) family and is involved in regulation of cell proliferation and differentiation. However, currently the role of ID2 in oxidative injury response in RPE cells remains unknown. Here we showed that oxidative stress increased ID2 expression in RPE cells. Knockdown of ID2 promoted cell apoptosis and increased ROS level in RPE cells that were subjected to oxidative damage. In addition, over-expression of ID2 attenuated the oxidative damage response in RPE cells. Mechanistically, ID2 protected RPE cells from oxidative damage through activating NRF2. Furthermore, phosphorylation of ERK1/2 positively regulated the protective function of ID2. Finally, we confirmed that the oxidative damage increased Id2 expression and over-expression of Id2 elevated Nrf2 expression in primary mouse RPE cells. Therefore, ID2 protects RPE cells from oxidative damage through the p-ERK1/2/ID2/NRF2 pathway. Our study contributes to a better understanding of the mechanisms underlying oxidative stress in AMD and may present a new strategy for AMD treatment.

Lenalidomide regulates osteocytes fate and related osteoclastogenesis via IL-1β/NF-κB/RANKL signaling

Osteolytic diseases are closely associated with osteocyte fate, indicating a more efficient and crucial role of osteocyte-targeting strategy in inhibiting osteoclastogenesis. Here, we investigated the effects of lenalidomide (Lena) on osteocyte fate in order to regulate osteoclastogenesis via effective cascade-controlling response. Our data revealed that lenalidomide treatment notably rescued IL-1β induced loss of osteocyte viability by inhibiting osteocyte apoptosis with decreased osteoclast-related factors, RANKL and Sclerostin, as demonstrated by the restricted osteoclast formation and reduced bone resorption. Additionally, iTRAQ assay revealed that IL-1β induced activation of NF-κB inhibitor α/β were remarkably downregulated by lenalidomide, showing that lenalidomide impaired NF-κB signaling in osteocytes for inhibiting the expression of osteoclast specific genes in osteoclasts, which was further confirmed by KEGG pathway analysis and Western blot. More interestingly, the in vivo analysis of osteocyte apoptosis and osteoclastogenesis in osteoarthritis mice model indicated a role of lenalidomide in the regulation of osteocyte fate and the consequent inhibition of RANKL-induced osteoclastogenesis. Together, these results suggest that lenalidomide regulates osteocyte fate by attenuating IL-1β/NF-κB signaling, thereby inhibiting RANKL expression for the attenuated osteoclastogenesis both in vitro and vivo, indicating a more efficient remedy among future anti-osteoclastogenesis approaches.