Erianin inhibits high glucose-induced retinal angiogenesis via blocking ERK1/2-regulated HIF-1α-VEGF/VEGFR2 signaling pathway

The STAT1-SLC31A1 axis: Potential regulation of cuproptosis in diabetic retinopathy

BACKGROUND

By identifying molecular biological markers linked to cuproptosis in diabetic retinopathy (DR), new pathobiological pathways and more accessible diagnostic markers can be developed.

METHODS

The datasets related to DR were acquired from the Gene Expression Omnibus database, while genes associated with cuproptosis were sourced from previously published compilations. Consensus clustering was conducted to delineate distinct DR subclasses. Feature genes were identified utilizing weighted correlation network analysis (WGCNA). Additionally, two machine-learning algorithms were employed to refine the selection of feature genes. Finally, we conducted preliminary validation experiments to ascertain the involvement of cuproptosis in DR development and the transcriptional regulation of critical genes using both the streptozotocin-induced diabetic mouse model and the high glucose-induced BV2 model.

RESULTS

In the STZ-induced diabetic mouse retinas, a decrease in the expression of cuproptosis signature proteins (FDX1, DLAT, and NDUFS8) suggested the occurrence of cuproptosis in DR. Subsequently, the expression of eight cuproptosis differential genes was validated through the STZ-induced diabetes and oxygen-induced retinopathy (OIR) models, with the key gene SLC31A1 showing upregulation in both models and dataset species. Further analyses, including weighted gene co-expression network analysis, GSVA, and immune infiltration analysis, indicated a close correlation between cuproptosis and microglia function. Additionally, validation in an in vitro model of microglia indicated the occurrence of cuproptosis in microglia under high glucose conditions, alongside abnormal expression of STAT1 with SLC31A1.

CONCLUSION

Our findings suggest that STAT1/SLC31A1 may pave the way for a deeper comprehension of the mechanistic basis of DR and offer potential therapeutic avenues.

SP1-Driven FOXM1 Upregulation Induces Dopaminergic Neuron Injury in Parkinson's Disease

The aberrant expression of Forkhead box M1 (FOXM1) has been associated with the pathological processes of Parkinson's disease (PD), but the upstream and downstream regulators remain poorly understood. This study sought to examine the underlying mechanism of FOXM1 in dopaminergic neuron injury in PD. Bioinformatics analysis was conducted to pinpoint the differential expression of FOXM1, which was verified in the nigral tissues of rotenone-lesioned mice and dopaminergic neuron MN9D cells. Interactions among SP1, FOXM1, SNAI2, and CXCL12 were analyzed. To evaluate their effects on dopaminergic neuron injury, the lentiviral vector-mediated manipulation of FOXM1, SP1, and CXCL12 was introduced in rotenone-lesioned mice and MN9D cells. SP1, FOXM1, SNAI2, and CXCL12 abundant expression occurred in rotenone-lesioned mice and MN9D cells. Silencing of FOXM1 delayed the rotenone-induced dopaminergic neuron injury in vitro. Mechanistically, SP1 was an upstream transcription factor of FOXM1 and upregulated FOXM1 expression, leading to increased SNAI2 and CXCL12 expression. In vivo, data confirmed that SP1 promoted dopaminergic neuron injury by activating the FOXM1/SNAI2/CXCL12 axis. Our data indicate that SP1 silencing has neuroprotective effects on dopaminergic neurons, which is dependent upon the inactivated FOXM1/SNAI2/CXCL12 axis.

Microglia in retinal angiogenesis and diabetic retinopathy

Diabetic retinopathy has a high probability of causing visual impairment or blindness throughout the disease progression and is characterized by the growth of new blood vessels in the retina at an advanced, proliferative stage. Microglia are a resident immune population in the central nervous system, known to play a crucial role in regulating retinal angiogenesis in both physiological and pathological conditions, including diabetic retinopathy. Physiologically, they are located close to blood vessels and are essential for forming new blood vessels (neovascularization). In diabetic retinopathy, microglia become widely activated, showing a distinct polarization phenotype that leads to their accumulation around neovascular tufts. These activated microglia induce pathogenic angiogenesis through the secretion of various angiogenic factors and by regulating the status of endothelial cells. Interestingly, some subtypes of microglia simultaneously promote the regression of neovascularization tufts and normal angiogenesis in neovascularization lesions. Modulating the state of microglial activation to ameliorate neovascularization thus appears as a promising potential therapeutic approach for managing diabetic retinopathy.

Targeting Grancalcin Accelerates Wound Healing by Improving Angiogenesis in Diabetes

Chronic diabetic wounds are a serious complication of diabetes and often result in limb amputations and confer high mortality rates. The proinflammatory secretome in the wound perpetuates defective neovascularization and contributes to dysregulated tissue repair. This study aims to design a gelatin methacrylamide (GelMA) hydrogel to sustained the release of grancalcin-neutralizing antibody (GCA-NAb) and evaluate it as a potential scaffold to promote diabetic wound healing. Results show that the expression of grancalcin(GCA), a protein secreted by bone marrow-derived immune cells, is elevated in the wound sites of individuals and animals with diabetic ulcers. Genetic inhibition of grancalcin expression accelerates vascularization and healing in an animal model. Mechanistic studies show that grancalcin binds to transient receptor potential melastatin 8(TRPM8) and partially inactivates its downstream signaling pathways, thereby impairing angiogenesis in vitro and ex vivo. Systemic or topical administration of a GCA-NAb accelerate wound repair in mice with diabetes. The data suggest that GCA is a potential therapeutic target for the treatment of diabetic ulcers.

Mechanism of Erianin anti-triple negative breast cancer based on transcriptomics methods and network pharmacology

Triple negative breast cancer (TNBC) is a highly aggressive illness that lacks effective targeted treatments. Although Erianin has shown potential antitumor properties, its precise mechanism of action and target in TNBC remain unclear, hampering the development of drugs. The present study investigated the underlying mechanism of action of Erianin in treating TNBC by using transcriptomics and network pharmacology approaches. We evaluated Erianin's bioactivity in TNBC cell lines and xenograft tumor models. The results showed that Erianin significantly inhibited TNBC cell proliferation and impeded tumor growth. A subsequent analysis of transcriptomic and network pharmacological data identified 51 mutual targets. Analysis of protein-protein interactions identified eight hub targets. Furthermore, molecular docking indicated that the PPARA binding energy was the lowest for Erianin among the hub targets, followed by ROCK2, PDGFRB, CCND1, MUC1, and CDK1. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis showed that the common targets were associated with multiple cancer-related signaling pathways, including focal adhesion, PI3K-Akt signaling pathway, Rap1 signaling pathway, microRNAs in cancer, and human papillomavirus infection. The results of the Western blot and immunohistochemistry experiment further showed that Erianin could suppress PI3K/Akt signaling pathway activation. After co-incubation with SC79, the cell inhibition rate of Erianin was decreased, which further confirmed that Erianin inhibits TNBC progression via the PI3K-AKT signaling pathway. In conclusion, our results indicated that Erianin has the potential to inhibit the proliferation of TNBC by downregulating the PI3K/AKT signaling pathway by transcriptomics and network pharmacology. Therefore, Erianin appears to be a promising compound for the effective treatment of TNBC.

Mechanistic insights into the alterations and regulation of the AKT signaling pathway in diabetic retinopathy

In the early stages of diabetic retinopathy (DR), diabetes-related hyperglycemia directly inhibits the AKT signaling pathway by increasing oxidative stress or inhibiting growth factor expression, which leads to retinal cell apoptosis, nerve proliferation and fundus microvascular disease. However, due to compensatory vascular hyperplasia in the late stage of DR, the vascular endothelial growth factor (VEGF)/phosphatidylinositol 3 kinase (PI3K)/AKT cascade is activated, resulting in opposite levels of AKT regulation compared with the early stage. Studies have shown that many factors, including insulin, insulin-like growth factor-1 (IGF-1), VEGF and others, can regulate the AKT pathway. Disruption of the insulin pathway decreases AKT activation. IGF-1 downregulation decreases the activation of AKT in DR, which abrogates the neuroprotective effect, upregulates VEGF expression and thus induces neovascularization. Although inhibiting VEGF is the main treatment for neovascularization in DR, excessive inhibition may lead to apoptosis in inner retinal neurons. AKT pathway substrates, including mammalian target of rapamycin (mTOR), forkhead box O (FOXO), glycogen synthase kinase-3 (GSK-3)/nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor kappa-B (NF-κB), are a research focus. mTOR inhibitors can delay or prevent retinal microangiopathy, whereas low mTOR activity can decrease retinal protein synthesis. Inactivated AKT fails to inhibit FOXO and thus causes apoptosis. The GSK-3/Nrf2 cascade regulates oxidation and inflammation in DR. NF-κB is activated in diabetic retinas and is involved in inflammation and apoptosis. Many pathways or vital activities, such as the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) and mitogen-activated protein kinase (MAPK) signaling pathways, interact with the AKT pathway to influence DR development. Numerous regulatory methods can simultaneously impact the AKT pathway and other pathways, and it is essential to consider both the connections and interactions between these pathways. In this review, we summarize changes in the AKT signaling pathway in DR and targeted drugs based on these potential sites.

Diabetic retinopathy: a comprehensive update on in vivo, in vitro and ex vivo experimental models

Diabetic retinopathy (DR), one of the leading causes of visual impairment and blindness worldwide, is one of the major microvascular complications in diabetes mellitus (DM). Globally, DR prevalence among DM patients is 25%, and 6% have vision-threatening problems among them. With the higher incidence of DM globally, more DR cases are expected to be seen in the future. In order to comprehend the pathophysiological mechanism of DR in humans and discover potential novel substances for the treatment of DR, investigations are typically conducted using various experimental models. Among the experimental models, in vivo models have contributed significantly to understanding DR pathogenesis. There are several types of in vivo models for DR research, which include chemical-induced, surgical-induced, diet-induced, and genetic models. Similarly, for the in vitro models, there are several cell types that are utilised in DR research, such as retinal endothelial cells, Müller cells, and glial cells. With the advancement of DR research, it is essential to have a comprehensive update on the various experimental models utilised to mimic DR environment. This review provides the update on the in vitro, in vivo, and ex vivo models used in DR research, focusing on their features, advantages, and limitations.

Macrophage/microglia polarization for the treatment of diabetic retinopathy

Macrophages/microglia are immune system defense and homeostatic cells that develop from bone marrow progenitor cells. According to the different phenotypes and immune responses of macrophages (Th1 and Th2), the two primary categories of polarized macrophages/microglia are those conventionally activated (M1) and alternatively activated (M2). Macrophage/microglial polarization is a key regulating factor in the development of inflammatory disorders, cancers, metabolic disturbances, and neural degeneration. Macrophage/microglial polarization is involved in inflammation, oxidative stress, pathological angiogenesis, and tissue healing processes in ocular diseases, particularly in diabetic retinopathy (DR). The functional phenotypes of macrophages/microglia affect disease progression and prognosis, and thus regulate the polarization or functional phenotype of microglia at different DR stages, which may offer new concepts for individualized therapy of DR. This review summarizes the involvement of macrophage/microglia polarization in physiological situations and in the pathological process of DR, and discusses the promising role of polarization in personalized treatment of DR.

Erianin: A phytoestrogen with therapeutic potential

Erianin, a phytoestrogen with therapeutic potential, is one of the major active components of Dendrobll caulis. Erianin has a variety of pharmacological effects, such as anti-tumor, anti-inflammatory, anti-diabetic retinopathy, anti-psoriasis, and antibacterial effects. Especially, in regard to the anti-tumor effect of erianin, the underlying molecular mechanism has been partly clarified. In fact, the numerous pharmacological actions of erianin are complex and interrelated, mainly including ERK1/2, PI3K/Akt, JAK2/STAT3, HIF-1α/PD-L1, PPT1/mTOR, JNK/c-Jun, and p38 MAPK signal pathway. However, on account of the poor water solubility and the low bioavailability of erianin, greatly affected and limited its further development and application. And it is worthwhile and meaningful to explore more extensive pharmacological effects and mechanisms, clarify pharmacokinetics, and synthesize the derivatives of erianin. Conclusively, in this paper, the pharmacological effects of erianin and its mechanism, pharmacokinetics, and derivatives studies were reviewed, in order to provide a reference for the development and application of erianin.

The signaling pathways of traditional Chinese medicine in treating diabetic retinopathy

Diabetic retinopathy (DR) is one of the common diabetic microvascular complications that occurs in the eyes and is closely associated with vision loss in working adults. However, the clinical treatment of DR is limited or accompanied by a large number of complications. Therefore, the development of new drugs for the treatment of DR is urgently needed. Traditional Chinese medicine (TCM) is widely used to treat DR in China, and its multi-pathway and multi-level characteristics can effectively address the complex pathogenesis of DR. Growing evidence suggests that inflammation, angiogenesis, and oxidative stress are the core pathological mechanisms in the development of DR. This study innovatively considers the aforementioned processes as the fundamental unit and sheds light on the molecular mechanisms and potential of TCM against DR in terms of signaling pathways. The results showed that NF-κB, MAPK/NF-κB, TLR4/NF-κB, VEGF/VEGFR2, HIF-1α/VEGF, STAT3, and Nrf2/HO-1 are the key signaling pathways for the treatment of DR by TCMs, which involved curcumolide, erianin, quercetin, blueberry anthocyanins, puerarin, arjunolic acid, ethanol extract of Scutellaria barbata D. Don, Celosia argentea L. extract, ethanol extract of Dendrobium chrysotoxum Lindl., Shengpuhuang-tang, and LuoTong formula. The purpose of this review is to update and summarize the signaling pathways of TCM in the treatment of DR and provide ideas for the development of new drugs against DR in the future.

16p11.2 haploinsufficiency reduces mitochondrial biogenesis in brain endothelial cells and alters brain metabolism in adult mice

Neurovascular abnormalities in mouse models of 16p11.2 deletion autism syndrome are reminiscent of alterations reported in murine models of glucose transporter deficiency, including reduced brain angiogenesis and behavioral alterations. Yet, whether cerebrovascular alterations in 16p11.2^df/+ mice affect brain metabolism is unknown. Here, we report that anesthetized 16p11.2^df/+ mice display elevated brain glucose uptake, a phenomenon recapitulated in mice with endothelial-specific 16p11.2 haplodeficiency. Awake 16p11.2^df/+ mice display attenuated relative fluctuations of extracellular brain glucose following systemic glucose administration. Targeted metabolomics on cerebral cortex extracts reveals enhanced metabolic responses to systemic glucose in 16p11.2^df/+ mice that also display reduced mitochondria number in brain endothelial cells. This is not associated with changes in mitochondria fusion or fission proteins, but 16p11.2^df/+ brain endothelial cells lack the splice variant NT-PGC-1α, suggesting defective mitochondrial biogenesis. We propose that altered brain metabolism in 16p11.2^df/+ mice is compensatory to endothelial dysfunction, shedding light on previously unknown adaptative responses.

Effects of diabetes on microglial physiology: a systematic review of in vitro, preclinical and clinical studies

Diabetes mellitus is a heterogeneous chronic metabolic disorder characterized by the presence of hyperglycemia, commonly preceded by a prediabetic state. The excess of blood glucose can damage multiple organs, including the brain. In fact, cognitive decline and dementia are increasingly being recognized as important comorbidities of diabetes. Despite the largely consistent link between diabetes and dementia, the underlying causes of neurodegeneration in diabetic patients remain to be elucidated. A common factor for almost all neurological disorders is neuroinflammation, a complex inflammatory process in the central nervous system for the most part orchestrated by microglial cells, the main representatives of the immune system in the brain. In this context, our research question aimed to understand how diabetes affects brain and/or retinal microglia physiology. We conducted a systematic search in PubMed and Web of Science to identify research items addressing the effects of diabetes on microglial phenotypic modulation, including critical neuroinflammatory mediators and their pathways. The literature search yielded 1327 records, including 18 patents. Based on the title and abstracts, 830 papers were screened from which 250 primary research papers met the eligibility criteria (original research articles with patients or with a strict diabetes model without comorbidities, that included direct data about microglia in the brain or retina), and 17 additional research papers were included through forward and backward citations, resulting in a total of 267 primary research articles included in the scoping systematic review. We reviewed all primary publications investigating the effects of diabetes and/or its main pathophysiological traits on microglia, including in vitro studies, preclinical models of diabetes and clinical studies on diabetic patients. Although a strict classification of microglia remains elusive given their capacity to adapt to the environment and their morphological, ultrastructural and molecular dynamism, diabetes modulates microglial phenotypic states, triggering specific responses that include upregulation of activity markers (such as Iba1, CD11b, CD68, MHC-II and F4/80), morphological shift to amoeboid shape, secretion of a wide variety of cytokines and chemokines, metabolic reprogramming and generalized increase of oxidative stress. Pathways commonly activated by diabetes-related conditions include NF-κB, NLRP3 inflammasome, fractalkine/CX3CR1, MAPKs, AGEs/RAGE and Akt/mTOR. Altogether, the detailed portrait of complex interactions between diabetes and microglia physiology presented here can be regarded as an important starting point for future research focused on the microglia-metabolism interface.

The roles of ERIANIN in tumor and innate immunity and its' perspectives in immunotherapy

Traditional Chinese medicine has been used in China for thousands of years. In 2022, the 14th Five-Year Plan for the Development of Traditional Chinese Medicine was released, aiming to enhance traditional Chinese medicine health services and improve policies and systems for high-quality traditional Chinese medicinal development by 2025. ERIANIN, the main component of the traditional Chinese medicine Dendrobium, plays an important role in anti-inflammatory, antiviral, antitumor, antiangiogenic, and other pharmacological effects. ERIANIN has broad-spectrum antitumor effects, and its tumor-suppressive effects have been confirmed in the study of various diseases, such as precancerous lesions of the stomach, gastric cancer, liver cancer, lung cancer, prostate cancer, bladder cancer, breast cancer, cervical cancer, osteosarcoma, colorectal cancer, leukaemia, nasopharyngeal cancer and melanoma through the multiple signaling pathways. Thus, the aim of this review was to systematically summarise the research on ERIANIN with the aim of serving as a reference for future research on this compound and briefly discuss some future perspectives development of ERIANIN in combined immunotherapy.

A relatively low glucose promotes the proliferation of vascular endothelial cells by suppressing VEGFR2 O-GlcNAcylation and its proteasome degradation

PURPOSE

Vascular endothelial growth factor receptors (VEGFRs) have been demonstrated to play a critical role in ischemic retinal diseases, as VEGFRs mediate hypoxia-induced neovascularization. Not only hypoxia, ischemia also induces the deficiency of glucose, yet its effects on VEGFR signal and neovascularization have seldom been studied. Bioinformatics analysis predicted that VEGFRs may be regulated by O-GlcNAcylation, while glucose deficiency influences the O-GlcNAcylation.

METHODS

In this study, we treated human retinal microvascular endothelial cells with low glucose (LG) alone or in combination with low oxygen (oxygen and glucose deprivation, OGD). Cell viability and apoptosis rate were used to evaluate cell growth characters.

RESULTS

LG (2.8 mmol/L) treatment induced mRNA and protein levels of VEGFR1, 2, 3 even in the presence of the protein synthesis inhibitor, cycloheximide (CHX), suggesting that the increase in VEGFR proteins is partially associated with post-translational modifications. Immunoprecipitation analysis showed that O-GlcNAc level was decreased by LG in both VEGFR1, 2, but a de-O-GlcNAc glycosylase inhibitor restored the O-GlcNAc levels. This inhibitor also abolished the LG-induced increase in VEGFR2 protein, whereas this effect was not disappeared in the presence of the proteasome inhibitor, MG132. Similar results were also observed under OGD condition. VEGFR2 knockdown more significantly retarded the growth of hRMECs and HUVECs than VEGFR1, 3 knockdown under LG and OGD conditions.

CONCLUSIONS

A relatively low glucose suppressed O-GlcNAcylation in VEGFR2, whereby inhibiting its proteasome degradation; up-regulated VEGFR2 promoted the proliferation of vascular endothelial cells under ischemic condition.

Progress in Traditional Chinese Medicine on Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR), a common and blinding diabetic microvascular complication, is a harmful metabolic effect caused by persistent hyperglycemia. Owing to the complex pathogenesis of DR, various clinical treatment methods cannot completely prevent its development and are accompanied by various complications. Therefore, there is an urgent need to identify new therapeutic drugs or complementary and alternative therapies. Traditional Chinese medicine (TCM) has the unique advantages of multi-level, multi-target, and minimal side effects. Accumulating evidence has proven that TCM may help delay or prevent the progression of DR. This paper reviews the effect and mechanism of representative TCMs (including extracts, identified compounds, and compound formulas) on DR in recent years and provides evidence for new drug development and clinical efficacy.

Radiosynthesis and tumor microPET/CT imaging of 18F-fluoroethoxylerianin, a 18F-Labeled Erianin Analogue

Abstract: Erianin is an active constituent of Dendrobium candidum. In this work, 18F -fluoroethoxylerianin([18F]FEE), a 18F-Labeled Erianin analogue, was designed and synthesized to evaluate the property of Erianin and related analogues by in vivo PET imaging. The initial product was separated and purified by liquid phase separation module Explora LC and simple homemade solid phase extraction, and high purity [18F]FEE was finally obtained. The radiochemical purity of [18F]FEE was determined by Radio-TLC and Radio-HPLC. [18F]FEE showed good stability in normal saline and serum, and could be quickly eliminated from mice. Cell experiments, biological distribution, and small animal PET/CT further showed that [18F]FEE had a high uptake rate in HepG2 tumor cells, and showed good imaging ability in HepG2 tumor model. The results of this study indicate that the synthesized 18F-Labeled Erianin analogue is an effective new probe for positron emission tomography (PET) imaging of HepG2 hepatocellular carcinoma, which provides an intuitive and reliable theoretical basis for the development of erianin as an anticancer drug.

Anticancer Activity of Erianin: Cancer-Specific Target Prediction Based on Network Pharmacology

Erianin is a major bisbenzyl compound extracted from Dendrobium chrysotoxum Lindl., an important traditional Chinese herb. In recent years, a growing body of evidence has proved the potential therapeutic effects of erianin on various cancers, including hepatoma, melanoma, non-small-cell lung carcinoma, myelogenous leukemia, breast cancer, and osteosarcoma. Especially, the pharmacological activities of erianin, such as antioxidant and anticancer activity, have been frequently demonstrated by plenty of studies. In this study, we firstly conducted a systematic review on reported anticancer activity of erianin. All updated valuable information regarding the underlying action mechanisms of erianin in specific cancer was recorded and summarized in this paper. Most importantly, based on the molecular structure of erianin, its potential molecular targets were analyzed and predicted by means of the SwissTargetPrediction online server (http://www.swisstargetprediction.ch). In the meantime, the potential therapeutic targets of 10 types of cancers in which erianin has been proved to have anticancer effects were also predicted via the Online Mendelian Inheritance in Man (OMIM) database (http://www.ncbi.nlm.nih.gov/omim). The overlapping targets may serve as valuable target candidates through which erianin exerts its anticancer activity. The clinical value of those targets was subsequently evaluated by analyzing their prognostic role in specific cancer using Kaplan-Meier plotter (http://Kmplot.com/analysis/) and Gene Expression Profiling Interactive Analysis (GEPIA) (http://gepia.cancer-pku.cn/). To better assess and verify the binding ability of erianin with its potential targets, molecular flexible docking was performed using Discovery Studio (DS). The valuable targets obtained from the above analysis and verification were further mapped to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway using the Database for Annotation, Visualization and Integrated Discovery (DAVID) (http://david.abcc.ncifcrf.gov/) to explore the possible signaling pathways disturbed/regulated by erianin. Furthermore, the in silico prediction of absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of erianin was also performed and provided in this paper. Overall, in this study, we aimed at 1) collecting all experiment-based important information regarding the anticancer effect and pharmacological mechanism of erianin, 2) providing the predicted therapeutic targets and signaling pathways that erianin might act on in cancers, and 3) especially providing in silico ADMET properties of erianin.

Mechanisms and Active Compounds Polysaccharides and Bibenzyls of Medicinal Dendrobiums for Diabetes Management

BACKGROUND

Medicinal dendrobiums are used popularly in traditional Chinese medicine for the treatment of diabetes, while their active compounds and mechanism remain unclear. This review aimed to evaluate the mechanism and active compounds of medicinal dendrobiums in diabetes management through a systematic approach.

METHODS

A systematic approach was conducted to search for the mechanism and active phytochemicals in Dendrobium responsible for anti-diabetic actions using databases PubMed, Embase, and SciFinder.

RESULTS

Current literature indicates polysaccharides, bibenzyls, phenanthrene, and alkaloids are commonly isolated in Dendrobium genusin which polysaccharides and bibenzyls are most aboundant. Many animal studies have shown that polysaccharides from the species of Dendrobium provide with antidiabetic effects by lowering glucose level and reversing chronic inflammation of T2DM taken orally at 200 mg/kg. Dendrobium polysaccharides protect pancreatic β-cell dysfunction and insulin resistance in liver. Dendrobium polysaccharides up-regulate the abundance of short-chain fatty acid to stimulate GLP-1 secretion through gut microbiota. Bibenzyls also have great potency to inhibit the progression of the chronic inflammation in cellular studies.

CONCLUSION

Polysaccharides and bibenzyls are the major active compounds in medicinal dendrobiums for diabetic management through the mechanisms of lowering glucose level and reversing chronic inflammation of T2DM by modulating pancreatic β-cell dysfunction and insulin resistance in liver as a result from gut microbita regulation.

Erianin Controls Collagen-Mediated Retinal Angiogenesis via the RhoA/ROCK1 Signaling Pathway Induced by the alpha2/beta1 Integrin-Collagen Interaction

Purpose

Erianin has been reported to inhibit tumor activity by suppressing the expression of integrins. It is hypothesized that erianin can inhibit retinal neovascularization in collagen by suppressing the expression of integrins. With an aim to test this hypothesis, the regulation of erianin on collagen-mediated retinal angiogenesis via the Ras homolog gene family member A (RhoA)/Rho-associated coiled-coil containing protein kinase 1 (ROCK1) signaling pathway induced by α2 and β1 integrin-collagen interactions was investigated.

Methods

The effects of erianin on human retinal vascular endothelial cells (HRVECs) were assessed in vitro using a hypoxia model in a three-dimensional cell culture induced by cobalt (II) chloride (CoCl2). A hypoxia-induced retinopathy model in adult zebrafish and zebrafish embryos was established to assess the antiangiogenic effect of erianin with and without vitreous collagen in vivo. The expression of α2 and β1 integrin and RhoA/ROCK1 pathway in HRVECs and zebrafish retinas were analyzed.

Results

In vitro, collagen improved the angiogenic potential of HRVECs, including migration, adhesion, and tube formation, in a three-dimensional cell culture model. Erianin suppressed the angiogenic processes of the CoCl2-induced hypoxia HRVEC model in a concentration-dependent manner. In vivo, erianin reduced retinal angiogenesis in the hypoxia-induced retinopathy model in adult and embryo zebrafish. Erianin inhibited the expression of α2 and β1 integrin and RhoA/ROCK1 in a hypoxia-induced model in vitro in three-dimensional cell culture and in vivo in adult zebrafish.

Conclusions

Collagen-mediated retinal angiogenesis may be regulated by erianin via the RhoA/ROCK1 signaling pathway induced by α2 and β1 integrin-collagen interactions. These findings suggest that erianin has the therapeutic potential on intraocular collagen-mediated retinal angiogenesis.

Research progress on exosomes/microRNAs in the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is the leakage and obstruction of retinal microvessels caused by chronic progressive diabetes that leads to a series of fundus lesions. If not treated or controlled, it will affect vision and even cause blindness. DR is caused by a variety of factors, and its pathogenesis is complex. Pericyte-related diseases are considered to be an important factor for DR in many pathogeneses, which can lead to DR development through direct or indirect mechanisms, but the specific mechanism remains unclear. Exosomes are small vesicles of 40-100 nm. Most cells can produce exosomes. They mediate intercellular communication by transporting microRNAs (miRNAs), proteins, mRNAs, DNA, or lipids to target cells. In humans, intermittent hypoxia has been reported to alter circulating excretory carriers, increase endothelial cell permeability, and promote dysfunction in vivo. Therefore, we believe that the changes in circulating exocrine secretion caused by hypoxia in DR may be involved in its progress. This article examines the possible roles of miRNAs, proteins, and DNA in DR occurrence and development and discusses their possible mechanisms and therapy. This may help to provide basic proof for the use of exocrine hormones to cure DR.

The Anti-Inflammatory Effect of the β1-Adrenergic Receptor Antagonist Metoprolol on High Glucose Treated Human Microvascular Retinal Endothelial Cells

Hyperglycemia-induced impairment of the blood-retinal barrier represents the main pathological event in diabetic retinopathy that is elicited by a reduced cellular response to an accumulation of reactive oxygen species (ROS) and increased inflammation. The purpose of the study was to evaluate whether the selective β1-adrenoreceptor (β1-AR) antagonist metoprolol could modulate the inflammatory response to hyperglycemic conditions. For this purpose, human retinal endothelial cells (HREC) were treated with normal (5 mM) or high glucose (25 mM, HG) in the presence of metoprolol (10 μM), epinephrine (1 μM), or both compounds. Metoprolol prevented both the HG-induced reduction of cell viability (MTT assays) and the modulation of the angiogenic potential of HREC (tube formation assays) reducing the TNF-α, IL-1β, and VEGF mRNA levels (qRT-PCR). Moreover, metoprolol prevented the increase in phospho-ERK1/2, phospho-cPLA₂, COX2, and protein levels (Western blot) as well as counteracting the translocation of ERK1/2 and cPLA₂ (high-content screening). Metoprolol reduced ROS accumulation in HG-stimulated HREC by activating the anti-oxidative cellular response mediated by the Keap1/Nrf2/HO-1 pathway. In conclusion, metoprolol exerted a dual effect on HG-stimulated HREC, decreasing the activation of the pro-inflammatory ERK1/2/cPLA₂/COX2 axis, and counteracting ROS accumulation by activating the Keap1/Nrf2/HO-1 pathway.

Erianin: A Direct NLRP3 Inhibitor With Remarkable Anti-Inflammatory Activity

Erianin (Eri) is the extract of Dendrobium chrysotoxum Lindl. The NLRP3 inflammasome is a multiprotein complex that plays key roles in a wide variety of chronic inflammation-driven human diseases. Nevertheless, little is known about the protection of Eri against NLRP3 inflammasome-related diseases. In this study, we demonstrated that Eri inhibited NLRP3 inflammasome activation in vitro and in vivo. Mechanistically, Eri directly interacted with NLRP3, leading to inhibition of NLRP3 inflammasome assembly. Eri associated with the Walker A motif in the NACHT domain and suppressed NLRP3 ATPase activity. In mouse models, Eri had therapeutic effects on peritonitis, gouty arthritis and type 2 diabetes, via NLRP3. More importantly, Eri was active ex vivo for synovial fluid cells and monocytes from patients with IAV infection and gout. Eri may serve as a potential novel therapeutic compound against NLRP3-driven diseases.

Knockdown of YKL-40 inhibits angiogenesis through regulation of VEGF/VEGFR2 and ERK1/2 signaling in endometrial cancer

Studies have demonstrated that small interfering RNA (siRNA) targeting YKL-40 (siYKL-40) inhibits the proliferation, migration, invasion, and induces antiapoptotic abilities of endometrial cancer (EC) HEC-1A cells. However, its effect on angiogenesis is unclear. The present study aimed to investigate the role of YKL-40 in endometrial cancer and the related molecular mechanisms. YKL-40 was knocked down by transfection with siYKL-40 and the effects on angiogenesis, cell viability, and signaling pathways were investigated. The results showed that siYKL-40 inhibited VEGFA levels and tube formation in endothelial cells. Additionally, inhibition of YKL-40 decreased the expression levels of vascular endothelial growth factor (VEGF), phosphorylated vascular endothelial growth factor receptor 2 (pVEGFR2), and phosphorylated extracellular signal-regulated kinases 1 and 2 (pERK1/2). Furthermore, a nude mice xenograft model of EC showed that siYKL-40 inhibited tumor growth. Inhibition of YKL-40 led to suppression of angiogenesis and reduction of microvessel density through VEGF/VEGFR2 and ERK1/2 signaling in endometrial cancer cells. Taken together, this study demonstrated novel molecular mechanisms for role of YKL-40 in EC.

Chromosome-scale assembly of the Dendrobium chrysotoxum genome enhances the understanding of orchid evolution

As one of the largest families of angiosperms, the Orchidaceae family is diverse. Dendrobium represents the second largest genus of the Orchidaceae. However, an assembled high-quality genome of species in this genus is lacking. Here, we report a chromosome-scale reference genome of Dendrobium chrysotoxum, an important ornamental and medicinal orchid species. The assembled genome size of D. chrysotoxum was 1.37 Gb, with a contig N50 value of 1.54 Mb. Of the sequences, 95.75% were anchored to 19 pseudochromosomes. There were 30,044 genes predicted in the D. chrysotoxum genome. Two whole-genome polyploidization events occurred in D. chrysotoxum. In terms of the second event, whole-genome duplication (WGD) was also found to have occurred in other Orchidaceae members, which diverged mainly via gene loss immediately after the WGD event occurred; the first duplication was found to have occurred in most monocots (tau event). We identified sugar transporter (SWEET) gene family expansion, which might be related to the abundant medicinal compounds and fleshy stems of D. chrysotoxum. MADS-box genes were identified in D. chrysotoxum, as well as members of TPS and Hsp90 gene families, which are associated with resistance, which may contribute to the adaptive evolution of orchids. We also investigated the interplay among carotenoid, ABA, and ethylene biosynthesis in D. chrysotoxum to elucidate the regulatory mechanisms of the short flowering period of orchids with yellow flowers. The reference D. chrysotoxum genome will provide important insights for further research on medicinal active ingredients and breeding and enhances the understanding of orchid evolution.

Hypoxic Pretreatment of Adipose-Derived Stem Cells Accelerates Diabetic Wound Healing via circ-Gcap14 and HIF-1α/VEGF Mediated Angiopoiesis

Background and Objectives

Adipose-derived stem cell (ADSC) transplantation improves stem cell paracrine function and can enhance wound healing. However, in diabetic patients, glucose-associated effects on this function and cell survival lead to impaired wound closure, thereby limiting ADSC transplantation efficiency. The hypoxia-inducible factor HIF-1α has an important protective function during wound healing. Here, we aim to clarify the regulatory mechanism of ADSCs.

Methods and Results

ADSCs were isolated from BALB/C mice adipose samples. We then used high-throughput sequencing to assess abnormal expression of circular RNAs (circRNAs). We also used an in vivo full-thickness skin defect mouse model to assess the effects of transplanted ADSC on diabetic wound closure. Hypoxic pretreatment of ADSCs accelerated diabetic wound closure, which enhanced angiogenic growth factor expression in our mouse model. High-throughput sequencing and RT-qPCR indicated that circ-Gcap14 was upregulated in hypoxic pretreated ADSCs. Similarly, circ-Gcap14 downregulation also decreased the therapeutic effects of ADSCs; however, circ-Gcap14 overexpression increased the effects of ADSC by promoting angiopoiesis. We also used a luciferase reporter assay to confirm that miR-18a-5p and HIF-1α were downstream targets of circ-Gcap14. HIF-1α expression plays an important role in increased VEGF level.

Conclusions

Based on our data, we suggest that circ-Gcap14 plays an important role in accelerating hypoxic ADSC-mediated diabetic wound closure, by enhancing mouse angiogenic growth factor expression and regulating downstream miR-18a-5p/HIF-1α expression.

Erianin inhibits human lung cancer cell growth via PI3K/Akt/mTOR pathway in vitro and in vivo

Erianin is a small-molecule compound that is isolated from Dendrobium chrysotoxum Lindl. In recent years, it has been found to have evident antitumor activity in various cancers, such as bladder cancer, cervical cancer, and nasopharyngeal carcinoma. In this study, we assessed the effect of erianin on lung cancer in terms of cell growth inhibition and the related mechanism. First, erianin at a concentration of less than 1 nmol/L exhibited cytotoxicity in H1975, A549, LLC lung cancer cells, did not cause marked growth inhibition in normal lung and kidney cells, induced obvious apoptosis and G2/M phase arrest of cells, and inhibited the migration and invasion of lung cancer cells in vitro. Second, in a mouse xenograft model of lewis lung cancer (LLC), oral administration of erianin (50, 35, and 10 mg kg^-1  day^-1 for 12 days) substantially inhibited nodule growth, reduced the fluorescence counts of lewis cells and the percentage vascularity of tumor tissues, increased the number of apoptotic tumor cells, the thymus indices, up-regulated the levels of interleukin (IL)-2 and tumor necrosis factor-α (TNF-α), decreased IL-10 levels and the spleen index, and enhanced immune function. Lastly, the possible targets of erianin were determined by molecular docking and verified via western blot assay. The results indicated that erianin may achieve the above effects via inhibiting the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway in vitro and vivo. Taken together, the results showed that erianin had obvious antitumor effects via inhibiting the PI3K/Akt/mTOR pathway in vitro and vivo and may have potential clinical value for the treatment of lung cancer.

Erianin induces triple-negative breast cancer cells apoptosis by activating PI3K/Akt pathway

BACKGROUND

Triple-negative breast cancer (TNBC) is a refractory subtype of breast cancer, 25-30% of which have dysregulation in the PI3K/AKT pathway. The present study investigated the anticancer effect of erianin on TNBC cell line and its underlying mechanism.

METHODS

After treatment with erianin, MTT assay was employed to determine the MDA-MB-231 and EFM-192A cell proliferation, the nucleus morphological changes were observed by DAPI staining. The cell cycle and apoptotic proportion were detected by flow cytometry. Western blot was performed to determine the cell cycle and apoptosis-related protein expression and PI3K pathways. Finally, the antiproliferative activity of erianin was further confirmed by adding or not adding PI3K agonists SC79.

RESULTS

Erianin inhibited the proliferation of MDA-MB-231 and EFM-192A cells in a dose-dependent manner, the IC50 were 70.96 and 78.58 nM, respectively. Erianin could cause cell cycle arrest at the G2/M phase, and the expressions of p21 and p27 were up-regulated, while the expressions of CDK1 and Cyclin B1 were down-regulated. Erianin also induced apoptosis via the mitochondrial pathway, with the up-regulation of the expression of Cyto C, PARP, Bax, active form of Caspase-3, and Caspase-9. Furthermore, p-PI3K and p-Akt expression were down-regulated by erianin. After co-incubation with SC79, the cell inhibition rate of erianin was decreased, which further confirmed that the attenuated PI3K/Akt pathway was relevant to the pro-apoptotic effect of erianin.

CONCLUSIONS

Erianin can inhibit the proliferation of TNBC cells and induce cell cycle arrest and apoptosis, which may ascribe to the abolish the activation of the PI3K/Akt pathway.

Mangiferin inhibits cell migration and angiogenesis via PI3K/AKT/mTOR signaling in high glucose‑ and hypoxia‑induced RRCECs

Mangiferin is a prominent active component that can be derived from several traditional herbs, including Mangifera indica L., Anemarrhena asphodeloides Bge., and Belamcanda chinensis (L.) DC., which displays antidiabetic properties. Diabetic retinopathy (DR), a serious complication caused by diabetes, is the leading cause of blindness. The present study aimed to evaluate the beneficial effects of mangiferin on high glucose (HG)/hypoxia‑induced rat retinal capillary endothelial cell (RRCEC) angiogenesis, as well as the underlying mechanisms. To establish an in vitro model of DR, RRCECs were exposed to 30 mM glucose and hypoxia. Following treatment with different doses of mangiferin (0.05, 0.1 or 0.2 µM), RRCEC viability, migration and angiogenesis were assessed by performing Cell Counting Kit 8, immunofluorescence, wound healing, Transwell and tube formation assays. Western blotting was conducted to evaluate protein expression levels. Furthermore, LY294002 and IGF‑1, an inhibitor and activator of the PI3K/AKT/mTOR signaling pathway, respectively, were used to verify the potential mechanisms underlying mangiferin. The results demonstrated that mangiferin notably inhibited HG/hypoxia‑induced RRCEC migration and angiogenesis. HG/hypoxia‑induced upregulation of hypoxia‑inducible factor‑1α, vascular endothelial growth factor, matrix metallopeptidase (MMP)2 and MMP9 expression levels and the phosphorylation of PI3K, AKT and mTOR in RRCECs was significantly reversed following treatment with mangiferin. Additionally, further activation of the PI3K/AKT signaling pathway by IGF‑1 inhibited the beneficial effects of mangiferin on RRCECs, whereas deactivation of the PI3K/AKT signaling pathway by LY294002 displayed the opposite results. Collectively, the results of the present study suggested that mangiferin suppressed RRCEC angiogenesis via modulating the PI3K/AKT/mTOR signaling pathway, which could serve as an effective treatment strategy for DR.

Erianin suppresses hepatocellular carcinoma cells through down-regulation of PI3K/AKT, p38 and ERK MAPK signaling pathways

BACKGROUND

Hepatocellular carcinoma (HCC) is the dominant pathological type of primary liver cancer and no effective methods are available for its treatment. Erianin is a natural product extracted from Dendrobium, which possesses multiple pharmacological activities, including antioxidative and antitumor activity.

OBJECTIVE

To evaluate the anti-HCC activities of erianin and explore its underlying mechanism.

METHODS

MTT assay and Crystal Violet staining assay were used to select the non-toxic concentrations for the subsequent experiments. The colony formation assay and PCNA fluorescent staining were used to investigate the antiproliferative effects of erianin on human SMMC-7721 and HepG2 cells. Wound healing and transwell test were used to analyze cell migration and invasion. Caspase3 and Tunel staining were used to detect apoptosis. Western blot was used to examine the expression levels of proteins associated with invasion and key proteins in the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), p38 and ERK mitogen-activated protein kinase (MAPK) signaling pathways.

RESULTS

Erianin inhibited HCC cell proliferation in a dose-dependent manner. Decreased migration rate and invaded cells were observed with erianin supplement. The expression of invasion-associated proteins in the erianin group was also down-regulated. Besides, more apoptotic cells were observed after erianin treatment. For the molecular mechanism, erianin inhibited the phosphorylation of Akt, ERK and P38 in the PI3K/Akt and ERK/P38 pathway.

CONCLUSION

We demonstrated, for the first time, that erianin inhibited the proliferation, migration, invasion and induced the apoptosis of HCC through PI3K/Akt, p38 and ERK MAPK signaling pathway, indicating that erianin is a promising agent for the HCC treatment.

Microbial Glycosylation of Phenanthrene and Bibenzyls by Mucor hiemalis

Microbial transformation of denthyrsinin (1), gigantol (2), and batatasin III (3), the major constituents of Dendrobium species (Orchidaceae), was performed using the filamentous fungus Mucor hiemalis KCTC 26779. Three glycosylated metabolites were obtained in the biotransformation of 1-3, and their structures were identified as denthyrsinin-6- O-β-d-glucoside (4), gigantol-5- O-β-d-glucoside (5), and batatasin III-3- O-β-d-glucoside (6) by analyzing 1-dimensional and 2-dimensional-nuclear magnetic resonance spectra, as well as high-resolution electrospray ionization mass spectral data. Among them, metabolite 4 has not been previously reported. Mucor hiemalis was revealed to catalyze enzymatically glucosylation of the hydroxyl group of phenanthrenes and bibenzyls. This research provides an efficient approach for the glycosylation of phenanthrenes and bibenzyls and can expand the library of available phenanthrene and bibenzyl derivatives for further biological evaluations.

Long non-coding RNA DANCR alleviates hypoxia-caused H9c2 cells damage through up regulation of HIF-1α

Hypoxia is an important cause of myocardial cell loss, further inducing various heart illnesses, including acute myocardial infraction (AMI). Long non-coding RNA (LncRNA) discrimination antagonising non-protein coding RNA (DANCR) was firstly identified as epidermal cell differentiation suppressor. Here, we aimed to explore the effects and mechanism of DNACR in hypoxia-induced H9c2 cells. Hypoxic cells were made through 94% N₂, 5% CO₂, and 1% O₂ environment for 24 h. Cell viability and apoptosis were detected via methyl thiazolyl tetrazolium (MTT) method and flow cytometry analysis, respectively. The expression of DANCR and HIF-1α was examined via qRT-PCR. The expression of proteins related to cell apoptosis and PI3K/AKT/mTOR and ERK1/2 signal pathways was examined through western blot analysis. We found that hypoxia induced obvious cell activity inhibition and apoptosis increasing in H9c2 cells. DANCR was negatively regulated under hypoxia condition. Overexpression of DANCR rescued activity and attenuated apoptosis. Moreover, the overexpression of DANCR elevated the activation of PI3K/AKT/mTOR and ERK1/2 pathways. Further study indicated that DANCR could up-regulate the expression of HIF-1α. Si-HIF-1α transfection could remove the beneficial effects of DANCR overexpression in hypoxia-caused H9c2 cells damage. In conclusion, DANCR alleviated hypoxia-caused H9c2 cells damage through positive regulation of HIF-1α.

Microglia and Inflammatory Responses in Diabetic Retinopathy

Diabetic retinopathy is a vision-threatening disease affecting neurons and microvasculature of the retina. The development of this disease is associated with the action of inflammatory factors that are connected to the activation of microglial cells, the resident tissue macrophages of the CNS. In the quiescent state, microglial cells help maintain tissue homeostasis in the retina through phagocytosis and control of low-grade inflammation. However, prolonged tissue stress due to hyperglycemia primes microglia to become overly reactive with the concomitant production of pro-inflammatory cytokines and chemokines causing chronic inflammation. In this review, we provide evidence of microglial cell activation and pro-inflammatory molecules associated with the development and progression of diabetic retinopathy. We further highlight innovative animal models that can mimic the disease in humans and discuss strategies in modulating microglial-mediated inflammation as potential therapeutic approaches in managing the disease.

Recent research progress on natural small molecule bibenzyls and its derivatives in Dendrobium species

Orchidaceous plant Dendrobium genus is often used as a tonic, and its phenolic components have attracted attention for its anti-tumor and anti-diabetic complications. Bibenzyls is one of the essential phenolic active ingredients in the Dendrobium genus. At present, 89 bibenzyl derivatives have been extracted and identified from 46 Dendrobium species. The activity studies have shown that 42 compounds have pharmaceutical activity. Among them, 23 compounds showed antitumor activity; 7 compounds showed anti-diabetes and its complications activity; 10 compounds exhibited neuroprotective effects; 18 compounds showed antioxidant effects; 11 compounds had anti-inflammatory activity; 3 compounds had Antiplatelet aggregation effects; 3 compounds had antibacterial and antiviral effects. The Bibenzyls is small-molecular compounds of natural origin and widely sourced. Previous studies showed that the bibenzyls has good anti-tumor, anti-diabetes and its complications, and neuroprotective effects, and it has great potential for treating tumors, diabetes and its complications, Alzheimer's disease (AD) and Parkinson's disease (PD). Additionally, compounds such as moscatilin (1), gigantol (2) and chrysotoxine (3) have been further studied as lead compounds, and compounds exhibited therapeutical effects had been synthesized. Enough pieces of evidences have shown that the Bibenzyls have good development prospects. This article reviews the pharmacological effects of bibenzyls in Dendrobium species and provides an idea for its further development.

Hypoxia-inducible factor-1α: A promising therapeutic target for vasculopathy in diabetic retinopathy

Diabetic retinopathy (DR) is a serious condition that can cause blindness in diabetic patients. It is a neurovascular disease, but the pathogenesis leading to the onset of this disease is still not completely understood. However, hypoxia with subsequent neovascularization is a characteristic phenomenon observed with DR. Cellular response to hypoxia is mediated by the transcriptional regulator hypoxia-inducible factor (HIF). Long-term research has shown that one isotype of HIF, HIF-1α, may play a pivotal role under hypoxic conditions, and an increasing number of studies have shown that HIF-1α and its target genes contribute to retinal neovascularization. Therefore, targeting HIF-1α may lead to more effective DR treatments. This review describes the possible mechanisms of HIF-1α in neovascularization of DR. Furthermore, various inhibitors of HIF-1α that may have viable potential in the treatment of DR are also discussed.

Adipose-derived mesenchymal stromal cells reverse high glucose-induced reduction of angiogenesis in human retinal microvascular endothelial cells

BACKGROUND AIMS

Diabetic retinopathy (DR) is characterized by a progressive alteration of the retinal microvasculature, arising from microaneurysms to leaky vessels and finally abnormal neovascularization. The hyperglycemia-mediated loss of pericytes is a key event in vessel degeneration causing vascular destabilization. To overcome this, mesenchymal stromal cells (MSCs) have been tested as pericyte replacement in several animal models showing repair and regeneration of DR-damaged vasculature.

METHODS

We hypothesized that adipose-derived mesenchymal stromal cells (ASCs) resist high glucose-induced challenges and protect human retinal microvascular endothelial cells (HRMVECs) from glucose-mediated injury. ASCs and HRMVECs were cultured under normal-glucose (NG; 1 g/L) and high-glucose (HG; 4.5 g/L) conditions comparing their phenotype and angiogenic potential.

RESULTS

Whereas ASCs were generally unaffected by HG, HG caused a reduction of the angiogenic potential in HRMVEC. Indeed, HG-treated HRMVECs formed fewer vascular tube structures in a basement membrane angiogenesis assay. However, this was not observed in a direct ASC and HRMVEC coculture angiogenesis assay. Increased oxidative stress levels appeared to be linked to the HG-induced reduction of angiogenesis, which could be restored by ASC-conditioned medium and antioxidant treatment.

CONCLUSIONS

These findings suggest that ASC resist HG-stress whereas endothelial cell angiogenic capacity is reduced. Thus, ASC may be potentially therapeutically active in DR by restoring angiogenic deficits in retinal endothelial cells by the secretion of proangiogenic factors. However, these data also inquire for a thorough risk assessment about the timing of the ASC-based cell therapy, which can be considered advantageous at early stage of DR, but possibly detrimental at the late neo-angiogenic stage of DR.

Moscatilin Induces Apoptosis in Human Head and Neck Squamous Cell Carcinoma Cells via JNK Signaling Pathway

Dendrobii Herba is an herbal medicine that uses the stems of Dendrobium species (Orchidacea). It has been traditionally used to treat fever, hydrodipsomania, stomach disorders, and amyotrophia. In our previous study, a bibenzyl compound, moscatilin, which is isolated from Dendrobii Herba, showed potent cytotoxicity against a FaDu human pharyngeal squamous carcinoma cell line. Prompted by this finding, we performed additional studies in FaDu cells to investigate the mechanism of action. Moscatilin induced FaDu cell death by using 5 μM of concentration and by mediating apoptosis, whereas cell proliferation following treatment with 1 μM of moscatilin was not suppressed to the same levels as by the anti-cancer agent, cisplatin. Apoptosis-related protein expression (cleaved caspase-8, cleaved caspase-7, cytochrome c, cleaved caspase-9, cleaved caspase-3, and poly (ADP-ribose) polymerase (PARP) was increased by treating with 5 μM of moscatilin. This suggests that moscatilin-mediated apoptosis is associated with the extrinsic and intrinsic apoptotic signaling pathways. In addition, moscatilin-induced apoptosis was mediated by the c-Jun N-terminal kinase (JNK) signaling pathway. Overall, this study identified additional biological activity of moscatilin derived from natural products and suggested its potential application as a chemotherapeutic agent for the management of head and neck squamous cell carcinoma.

Erianin Induces Apoptosis and Autophagy in Oral Squamous Cell Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is a leading cause of cancer-related deaths worldwide. It has a very poor prognosis with over a 5-year survival rate of only 50%. Thus, it is important to identify effective therapeutic interventions against oral cancer. Apoptosis and autophagy have reported genetically regulated in physiology and diseases, which close relationship. Many natural compound study objects anticancer effect have been studied between apoptosis and autophagy relationship. The present study was designed to evaluate the effect of erianin on human oral cancer cell proliferation. Results of the study revealed that treatment with erianin significantly reduced the viability of different OSCC cell lines. Erianin exerted its cytotoxic effect by inducing cell cycle arrest and caspase-dependent apoptotic pathways. Both intrinsic and extrinsic pathways were found to be involved in erianin-mediated cell death. In addition, treatment with erianin also increased autophagy in OSCC cells. With further analysis, it was found that erianin induced both apoptosis and autophagy by regulating MAPK signaling pathways. Taken together, our study indicates that erianin plays an important role in reducing oral cancer cell viability, and thus, can be considered as a potential anticancer agent.

Aqueous extract of Dendrobium officinale confers neuroprotection against hypoxic-ischemic brain damage in neonatal rats

Accumulating evidences have proved the protective role of traditional Chinese medicine in improving neurological damage induced by cerebral hypoxia-ischemia. Herein, we hypothesized that Dendrobium officinale aqueous extract exerted neuroprotection against brain damage. Initially, a model of hypoxic-ischemic brain damage (HIBD) was induced in neonatal rats, which were subsequently intragastrically administered with different doses of Dendrobium officinale aqueous extract. Next, the antioxidant capacity was examined by enzyme-linked immunosorbent assay. 2,3,5-Triphenyltetrazolium chloride and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining assays were adopted to determine neuronal apoptosis in brain tissues. Furthermore, neurotrophic factors and hypoxia-inducible factor-1α (HIF-1α) expression was identified by Western blot analysis. The neonatal rat models of HIBD presented impaired neurobehaviors and antioxidant capacity, increased neuronal apoptosis and expression of HIF-1α and histone deacetylase 1 (HDAC1), as well as diminished expression of neurotrophic factors and K⁺ -Cl^- -cotransporter 2 (KCC2). Notably, in response to different doses of Dendrobium officinale aqueous extract, the impairment on neurobehaviors and antioxidant capacity was alleviated, accompanied by reduced levels of nitric oxide synthase, nitric oxide, and malondialdehyde, and increased superoxide dismutase activity. Besides, the neuronal apoptosis was inhibited as reflected by down-regulated cleaved caspase-3 and Bax and up-regulated Bcl-2. Moreover, we also found accelerated expression of neurotrophic factors and KCC2 and diminished expression of HIF-1α and HDAC1. Altogether, this present study highlights that the aqueous extract of Dendrobium officinale can suppress the neuronal apoptosis and enhance the expression of neurotrophic factors to protect neonatal rats against HIBD.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Erianin alleviates diabetic retinopathy by reducing retinal inflammation initiated by microglial cells via inhibiting hyperglycemia-mediated ERK1/2-NF-κB signaling pathway

Blood-retinal barrier (BRB) breakdown is a typical event in the early stage of diabetic retinopathy (DR). This study aims to elucidate the protection of erianin, a natural compound isolated from Dendrobium chrysotoxum Lindl, against DR development. Erianin alleviated BRB breakdown and rescued the reduced claudin1 and occludin expression in retinas from streptozotocin-induced diabetic mice. Erianin reduced microglial activation, ERK1/2 phosphorylation, NF-κB transcriptional activation, and the elevated TNF-α expression both in vitro and in vivo. ERK1/2 inhibitor U0126 abrogated NF-κB activation in d-glucose-treated BV2 cells. Erianin reduced cellular glucose uptake, and molecular docking analysis indicated the potential interaction of erianin with glucose transporter (GLUT)1. GLUT1 inhibitor (STF31) reduced the activation of the ERK1/2-NF-κB signaling pathway. Coculture with d-glucose-stimulated microglial BV2 cells and with TNF-α stimulation both induced inner BRB and outer BRB damage in human retinal endothelial cells and APRE19 cells, but erianin improved all these damages. In summary, erianin attenuated BRB breakdown during DR development by inhibiting microglia-triggered retinal inflammation via reducing cellular glucose uptake and abrogating the subsequent activation of the downstream ERK1/2-NF-κB pathway. Moreover, erianin also alleviated BRB damage induced by TNF-α released from the activated microglia.-Zhang, T., Ouyang, H., Mei, X., Lu, B., Yu, Z., Chen, K., Wang, Z., Ji, L. Erianin alleviates diabetic retinopathy by reducing retinal inflammation initiated by microglial cells via inhibiting hyperglycemia-mediated ERK1/2-NF-κB signaling pathway.

Erianin Inhibits Proliferation and Induces Apoptosis of HaCaT Cells via ROS-Mediated JNK/c-Jun and AKT/mTOR Signaling Pathways

Psoriasis is a recurrent skin disease described as keratinocyte hyperproliferation and aberrant differentiation. Erianin, a bibenzyl compound extracted from Dendrobium chrysotoxum, has displayed antitumor and anti-angiogenesis effects. However, the effects of erianin on a human keratinocyte cell line (HaCaT) are not fully understood. In the present study, we explored the effect of erianin on proliferation and apoptosis in HaCaT cells. Our results indicated that treatment with erianin ranging from 12.5 nM to 50 nM inhibited proliferation and induced apoptosis of HaCaT cells. In addition, erianin-induced apoptosis was accompanied by elevated reactive oxygen species (ROS). The ROS scavenger N-acetyl-cysteine (NAC) attenuated this elevation. Moreover, treatment with erianin induced activation of the c-Jun N-terminal kinase (JNK)/c-Jun signaling pathway and suppressed the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, while pretreatment with NAC also reversed these effects. Collectively, these data demonstrated that erianin inhibited proliferation and induced apoptosis of HaCaT cells through ROS-mediated JNK/c-Jun and AKT/mTOR signaling pathways. Erianin could be recognized as a potential anti-psoriasis drug.

Progressive study of effects of erianin on anticancer activity

Erianin is the major bisbenzyl compound extracted from the traditional Chinese medicine Dendrohium chrysotoxum Lindl. Erianin possesses many biological properties relevant to cancer prevention and therapy. The previous studies confirmed that antitumor effects of erianin are regulated with multiple signaling pathways. The mechanisms of erianin are numerous, and most of them induce cancer cell apoptosis that may be intrinsic or extrinsic and modulate the ROS/JNK signaling pathways. Invasion, migration, and angiogenesis represent emerging targets of erianin and support its anticancer properties. This review aimed to summarize the recent advances in the antitumor activity of erianin and to provide a rationale for further exploring the potential application of erianin in overcoming cancer in the future.

Identification of Two New Phenanthrenes from Dendrobii Herba and Their Cytotoxicity towards Human Hypopharynx Squamous Carcinoma Cell (FaDu)

Two new phenanthrenes, (1R,2R)-1,7-hydroxy-2,8-methoxy-2,3-dihydrophenanthrene-4(1H)-one (1) and 2,7-dihydroxy-phenanthrene-1,4-dione (2), were isolated from the ethyl acetate-soluble fraction of Dendrobii Herba, together with seven known phenanthrenes (3–9), two bibenzyls (10–12), and a lignan (13). Structures of 1 and 2 were elucidated by analyzing one-dimensional (1D) and two-dimensional (2D)-NMR and High-resolution electrospray ionization mass spectra (HR-ESI-MS) data. The absolute configuration of compound 1 was confirmed by the circular dichroism (CD) spectroscopic method. In cytotoxicity assay using FaDu human hypopharynx squamous carcinoma cell line, compounds 3–6, 8, 10, and 12 showed activities, with IC₅₀ values that ranged from 2.55 to 17.70 μM.

Natural flavonoid galangin alleviates microglia-trigged blood-retinal barrier dysfunction during the development of diabetic retinopathy

Hyperglycemia-induced blood-retinal barrier (BRB) breakdown is an early and typical event of diabetic retinopathy (DR). Although chronic inflammation plays an important role in DR development, the concrete mechanism remains unclear. This study aims to investigate the role of microglia cells-triggered inflammatory response in hyperglycemia-induced BRB breakdown and the amelioration of galangin, a natural flavonoid. Galangin alleviated BRB breakdown in streptozotocin-induced diabetic mice. D-glucose (25 mM)-stimulated microglia BV2 cells induced BRB damage in vitro, but galangin reversed this injury. Galangin decreased the activation of microglia cells, ROS formation, the phosphorylation of extracellular-signal-regulated protein kinase (ERK)1/2, the transcriptional activation of nuclear factor κB (NFκB) and early growth response (Egr1) protein, and the elevated expression of tumor necrosis factor (TNF)-α both in vitro and in vivo. ERK1/2 inhibitor U0126 reduced ROS formation, the activation of NFκB and Egr1, and the elevated TNFα expression in D-glucose-stimulated BV2 cells. N-acetylcysteine, a well-known antioxidant, abrogated D-glucose-induced NFκB and Egr1 activation in BV2 cells. Galangin also reversed the decreased expression of claudin1 and occludin, and the increased BRB injury and ROS formation in TNFα-treated human retinal endothelial cells (HRECs) and ARPE19 cells. Galangin induced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in both HRECs and ARPE19 cells. Moreover, the galangin-provided attenuation on BRB breakdown was diminished in Nrf2 knockout diabetic mice. In conclusion, galangin alleviated DR by attenuating BRB damage via inhibiting microglia-triggered inflammation and further reversing TNFα-induced BRB dysfunction by abrogating oxidative stress injury via activating Nrf2.