Mangiferin has an additive effect on the apoptotic properties of hesperidin in Cyclopia sp. tea extracts

Nano-delivery Systems and Therapeutic Applications of Phytodrug Mangiferin

In order to cure a range of ailments, scientists have investigated a number of bioactive antioxidant compounds produced from natural sources. Mangiferin, a C-glycosyl xanthone-structured yellow polyphenol, is abundant in mangoes and other dietary sources. In-depth examinations found that it is effective in the treatment of a variety of disorders due to its antiviral, anti-inflammatory, antiproliferative, antigenotoxic, antiatherogenic, radioprotective, nephroprotective, antihyperlipidemic, and antidiabetic properties. However, it is recognised that mangiferin's poor bioavailability, volatility, and limited solubility restrict its therapeutic usefulness. Over time, effective solutions to these problems have arisen in the shape of effective delivery methods. The current articles present a summary of the several researches that have updated Mangiferin's biopharmaceutical characteristics. Additionally, strategies for enhancing the bioavailability, stability, and solubility of this phytodrug have been discussed. This review provides detailed information on the development of innovative Mangiferin delivery methods such as nanoparticles, liposomes, micelles, niosomes, microspheres, metal nanoparticles, and complexation, as well as its therapeutic applications in a variety of sectors. This article provides effective guidance for researchers who desire to work on the formulation and development of an effective delivery method for improved magniferin therapeutic effectiveness.

Encapsulation of Gemcitabine on Porphyrin Aluminum Metal-Organic Framework by Mechano-Chemistry, Delayed Drug Release and Cytotoxicity to Pancreatic Cancer PANC-1 Cells

Gemcitabine is a widely used antimetabolite drug of pyrimidine structure, which can exist as a free-base molecular form (Gem). The encapsulated forms of medicinal drugs are of interest for delayed and local drug release. We utilized, for the first time, a novel approach of mechano-chemistry by liquid-assisted grinding (LAG) to encapsulate Gem on a "matrix" of porphyrin aluminum metal-organic framework Al-MOF-TCPPH2 (compound 2). The chemical bonding of Gem to compound 2 was studied by ATR-FTIR spectroscopy and powder XRD. The interaction involves the C=O group of Gem molecules, which indicates the formation of the encapsulation complex in the obtained composite. Further, the delayed release of Gem from the composite was studied to phosphate buffered saline (PBS) at 37 °C using an automated drug dissolution apparatus equipped with an autosampler. The concentration of the released drug was determined by HPLC-UV analysis. The composite shows delayed release of Gem due to the bonded form and constant concentration thereafter, while pure Gem shows quick dissolution in less than 45 min. Delayed release of Gem drug from the composite follows the kinetic pseudo-first-order rate law. Further, for the first time, the mechanism of delayed release of Gem was assessed by the variable stirring speed of drug release media, and kinetic rate constant k was found to decrease when stirring speed is decreased (diffusion control). Finally, the prolonged time scale of toxicity of Gem to pancreatic cancer PANC-1 cells was studied by continuous measurements of proliferation (growth) for 6 days, using the xCELLigence real-time cell analyzer (RTCA), for the composite vs. pure drug, and their differences indicate delayed drug release. Aluminum metal-organic frameworks are new and promising materials for the encapsulation of gemcitabine and related small-molecule antimetabolites for controlled delayed drug release and potential use in drug-eluting implants.

Elucidating molecular and cellular targets and the antiprostate cancer potentials of promising phytochemicals: a review

Prostate cancer (PCa) has become the major health problem and the leading causes of cancer mortality among men. PCa often progresses from an early androgen-dependent form of cancer to a late (metastatic) androgen-independent cancer, for which no effective treatment options are available. Current therapies target testosterone depletion, androgen axis inhibition, androgen receptor (AR) downregulation and regulation PSA expression. These conventional treatment options, however, are intense and pose severe side effects. From the past few years, plant-derived compounds or phytochemicals have attracted much attention by the researchers worldwide for their promising approach in inhibiting the development and growth of cancer. This review emphasizes mechanistic role of promising phytochemicals on PCa. This review imparts to score anticancer efficacy of promising phyto-agents luteolin, fisetin, coumestrol and hesperidin with focus on the mechanistic action in management and treatment of PCa. These phytocompounds were also selected for their best binding affinity with the ARs on the basis of molecular docking studies.

Nanotechnology-Based Drug Delivery Approaches of Mangiferin: Promises, Reality and Challenges in Cancer Chemotherapy

Mangiferin (MGF), a xanthone derived from Mangifera indica L., initially employed as a nutraceutical, is now being explored extensively for its anticancer potential. Scientists across the globe have explored this bioactive for managing a variety of cancers using validated in vitro and in vivo models. The in vitro anticancer potential of this biomolecule on well-established breast cancer cell lines such as MDA-MB-23, BEAS-2B cells and MCF-7 is closer to many approved synthetic anticancer agents. However, the solubility and bioavailability of this xanthone are the main challenges, and its oral bioavailability is reported to be less than 2%, and its aqueous solubility is also 0.111 mg/mL. Nano-drug delivery systems have attempted to deliver the drugs at the desired site at a desired rate in desired amounts. Many researchers have explored various nanotechnology-based approaches to provide effective and safe delivery of mangiferin for cancer therapy. Nanoparticles were used as carriers to encapsulate mangiferin, protecting it from degradation and facilitating its delivery to cancer cells. They have attempted to enhance the bioavailability, safety and efficacy of this very bioactive using drug delivery approaches. The present review focuses on the origin and structure elucidation of mangiferin and its derivatives and the benefits of this bioactive. The review also offers insight into the delivery-related challenges of mangiferin and its applications in nanosized forms against cancer. The use of a relatively new deep-learning approach to solve the pharmacokinetic issues of this bioactive has also been discussed. The review also critically analyzes the future hope for mangiferin as a therapeutic agent for cancer management.

Photoprotection and Antiaging Activity of Extracts from Honeybush (Cyclopia sp.)-In Vitro Wound Healing and Inhibition of the Skin Extracellular Matrix Enzymes: Tyrosinase, Collagenase, Elastase and Hyaluronidase

Cyclopia sp. (honeybush) is an African shrub known as a rich source of polyphenols. The biological effects of fermented honeybush extracts were investigated. The influence of honeybush extracts on extracellular matrix (ECM) enzymes responsible for the skin malfunction and aging process-collagenase, elastase, tyrosinase and hyaluronidase-was analysed. The research also included assessment of the in vitro photoprotection efficiency of honeybush extracts and their contribution to the wound healing process. Antioxidant properties of the prepared extracts were evaluated, and quantification of the main compounds in the extracts was achieved. The research showed that the analysed extracts had a significant ability to inhibit collagenase, tyrosinase and hyaluronidase and a weak influence on elastase activity. Tyrosinase was inhibited effectively by honeybush acetone (IC₅₀ 26.18 ± 1.45 µg/mL), ethanol (IC₅₀ 45.99 ± 0.76 µg/mL) and water (IC₅₀ 67.42 ± 1.75 µg/mL) extracts. Significant hyaluronidase inhibition was observed for ethanol, acetone and water extracts (IC₅₀ were 10.99 ± 1.56, 13.21 ± 0.39 and 14.62 ± 0.21µg/mL, respectively). Collagenase activity was inhibited effectively by honeybush acetone extract (IC₅₀ 42.5 ± 1.05 μg/mL). The wound healing properties of the honeybush extracts, estimated in vitro in human keratinocytes (HaCaTs), were indicated for water and ethanol extracts. In vitro sun protection factor (SPF in vitro) showed medium photoprotection potential for all the honeybush extracts. The quantity of polyphenolic compounds was estimated with the use of high-performance liquid chromatography equipped with diode-array detection (HPLC-DAD), indicating the highest mangiferin contents in ethanol, acetone and n-butanol extracts, while in the water extract hesperidin was the dominant compound. The antioxidant properties of the honeybush extracts were estimated with FRAP (2,4,6-Tris(2-pyridyl)-s-triazine) and DPPH (2,2-diphenyl-1-picrylhydrazyl) tests, indicating their strong antioxidant activity, similar to ascorbic acid for the acetone extract in both tests. The wound healing abilities, estimation of SPF in vitro and the direct influence on selected enzymes (elastase, tyrosinase, collagenase and hyaluronidase) of the tested honeybush extracts were analysed for the first time, indicating a high potential of these well-known herbal tea for antiaging, anti-inflammation, regeneration and protection of the skin.

Mangiferin Affects Melanin Synthesis by an Influence on Tyrosinase: Inhibition, Mechanism of Action and Molecular Docking Studies

Mangiferin is a strong antioxidant that presents a wide range of biological activities. The aim of this study was to evaluate, for the first time, the influence of mangiferin on tyrosinase, an enzyme responsible for melanin synthesis and the unwanted browning process of food. The research included both the kinetics and molecular interactions between tyrosinase and mangiferin. The research proved that mangiferin inhibits tyrosinase activity in a dose-dependent manner with IC₅₀ 290 +/- 6.04 µM, which was found comparable with the standard kojic acid (IC₅₀ 217.45 +/- 2.54 µM). The mechanism of inhibition was described as mixed inhibition. The interaction between tyrosinase enzyme and mangiferin was confirmed with capillary electrophoresis (CE). The analysis indicated the formation of two main, and four less significant complexes. These results have also been supported by the molecular docking studies. It was indicated that mangiferin binds to tyrosinase, similarly to L-DOPA molecule, both in the active center and peripheral site. As it was presented in molecular docking studies, mangiferin and L-DOPA molecules can interact in a similar way with surrounding amino acid residues of tyrosinase. Additionally, hydroxyl groups of mangiferin may interact with amino acids on the tyrosinase external surface causing non-specific interaction.

The Use of Medicinal Plant-Derived Metallic Nanoparticles in Theranostics

In the quest to effectively diagnose and treat the diseases that afflict mankind, the development of a tool capable of simultaneous detection and treatment would provide a significant cornerstone for the survival and control of these diseases. Theranostics denotes a portmanteau of therapeutics and diagnostics which simultaneously detect and treat ailments. Research advances have initiated the advent of theranostics in modern medicine. Overall, theranostics are drug delivery systems with molecular or targeted imaging agents integrated into their structure. The application of theranostics is rising exponentially due to the urgent need for treatments that can be utilized for diagnostic imaging as an aid in precision and personalised medicine. Subsequently, the emergence of nanobiotechnology and the green synthesis of metallic nanoparticles (MNPs) has provided one such avenue for nanoscale development and research. Of interest is the drastic rise in the use of medicinal plants in the synthesis of MNPs which have been reported to be potentially effective in the diagnosis and treatment of diseases. At present, medicinal plant-derived MNPs have been cited to have broad pharmacological applications and have been studied for their potential use in the treatment and management of cancer, malaria, microbial and cardiovascular diseases. The subject of this article regards the role of medicinal plants in the synthesis of MNPs and the potential role of MNPs in the field of theranostics.

Mangiferin and Hesperidin Transdermal Distribution and Permeability through the Skin from Solutions and Honeybush Extracts (Cyclopia sp.)-A Comparison Ex Vivo Study

Polyphenolic compounds—mangiferin and hesperidin—are, among others, the most important secondary metabolites of African shrub Cyclopia sp. (honeybush). The aim of this study was to compare the percutaneous absorption of mangiferin and hesperidin from solutions (water, ethanol 50%, (v/v)) and extracts obtained from green and fermented honeybush (water, ethanol 50%, (v/v)). Research was performed with the Bronaugh cells, on human dorsal skin. The mangiferin and hesperidin distributions in skin layers (stratum corneum, epidermis, and dermis) and in acceptor fluid (in every 2, 4, 6, and 24 h) were evaluated by HPLC–Photodiode Array Coulometric and Coulometric Electrochemical Array Detection. The transdermal distribution of hesperidin was also demonstrated by fluorescence microscopy. Results indicated that mangiferin and hesperidin were able to cross the stratum corneum and penetrate into the epidermis and dermis. An advantage of hesperidin penetration into the skin from the water over ethanol solution was observed (451.02 ± 14.50 vs. 357.39 ± 4.51 ng/cm²), as well as in the mangiferin study (127.56 ± 9.49 vs. 97.23 ± 2.92 ng/cm²). Furthermore, mangiferin penetration was more evident from nonfermented honeybush ethanol extract (189.85 ± 4.11 ng/cm²) than from solutions. The permeation of mangiferin and hesperidin through the skin to the acceptor fluid was observed regardless of whether the solution or the honeybush extract was applied. The highest ability to permeate the skin was demonstrated for the water solution of hesperidin (250.92 ± 16.01 ng/cm²), while the hesperidin occurring in the extracts permeated in a very low capacity. Mangiferin from nonfermented honeybush ethanol extract had the highest ability to permeate to the acceptor fluid within 24 h (152.36 ± 8.57 ng/cm²).

Mangiferin as New Potential Anti-Cancer Agent and Mangiferin-Integrated Polymer Systems-A Novel Research Direction

For a long time, the pharmaceutical industry focused on natural biologically active molecules due to their unique properties, availability and significantly less side-effects. Mangiferin is a naturally occurring C-glucosylxantone that has substantial potential for the treatment of various diseases thanks to its numerous biological activities. Many research studies have proven that mangiferin possesses antioxidant, anti-infection, anti-cancer, anti-diabetic, cardiovascular, neuroprotective properties and it also increases immunity. It is especially important that it has no toxicity. However, mangiferin is not being currently applied to clinical use because its oral bioavailability as well as its absorption in the body are too low. To improve the solubility, enhance the biological action and bioavailability, mangiferin integrated polymer systems have been developed. In this paper, we review molecular mechanisms of anti-cancer action as well as a number of designed polymer-mangiferin systems. Taking together, mangiferin is a very promising anti-cancer molecule with excellent properties and the absence of toxicity.

Artichoke extracts in cancer therapy: do the extraction conditions affect the anticancer activity?

Background

Artichoke is an edible plant that is grown in the Mediterranean region and is known for its antimicrobial, antifungal, antibacterial, antioxidant and anticancer activities. Different artichoke extraction methods can impressively affect the nature as well as the yield of the extracted components.

Main body

The different methods of artichoke extraction and the influence of the extraction conditions on the extraction efficiency are summarized herein. In addition, cancer causalities and hallmarks together with the molecular mechanisms of artichoke active molecules in cancer treatment are also discussed. Moreover, a short background is given on the common types of cancer that can be treated with artichoke extracts as well as their pathogenesis. A brief discussion of the previous works devoted to the application of artichoke extracts in the treatment of these cancers is also given.

Conclusion

This review article covers the extraction methods, composition, utilization and applications of artichoke extracts in the treatment of different cancers.

Therapeutic potential of hesperidin and its aglycone hesperetin: Cell cycle regulation and apoptosis induction in cancer models

BACKGROUND

The ability of cancer cells to divide without restriction and to escape programmed cell death is a feature of the proliferative state. Citrus flavanones are flavonoids with potential multiple anticancer actions, from antioxidant and chemopreventive, to anti-inflammatory, anti-angiogenic, cytostatic and cytotoxic in different cancer models.

PURPOSE

This review aims to summarize the current knowledge on the antiproliferative actions of the citrus flavanones hesperidin (HSD) and hesperetin (HST), with emphasis on cell cycle arrest and apoptosis.

METHODS

Cochrane Library, Scopus, Pubmed and Web of Science collection databases were queried for publications reporting antiproliferative effects of HSD and HST in cancer models.

RESULTS

HSD and HST have been proven to delay cell proliferation in several cancer models. Depending on the compound, dose and cell line studied, different effects have been reported. Cell cycle arrest associated with cytostatic effects has been reported in cells with increased levels of p53 and also cyclin-dependent kinase inhibitors, as well as decreased levels of specific cyclins and cyclin-dependent kinases. Moreover, apoptotic effects have been found to be associated with altered ratios of pro-/antiapoptotic proteins, caspase activation, c-Jun N-terminal kinase (JNK) pathway activation and caspase-independent pathways.

CONCLUSION

Available scientific literature data indicate complex effects, dependent on cell lines and exposure conditions, suggesting that HSD and HST doses need to be optimized according to the cellular and organismal context. The establishment of the main antiproliferative mechanisms is of utmost importance for a possible therapeutic benefit of citrus flavanones in the context of cancer.

Utilizing Genome-Wide mRNA Profiling to Identify the Cytotoxic Chemotherapeutic Mechanism of Triazoloacridone C-1305 as Direct Microtubule Stabilization

Rational drug design and in vitro pharmacology profiling constitute the gold standard in drug development pipelines. Problems arise, however, because this process is often difficult due to limited information regarding the complete identification of a molecule’s biological activities. The increasing affordability of genome-wide next-generation technologies now provides an excellent opportunity to understand a compound’s diverse effects on gene regulation. Here, we used an unbiased approach in lung and colon cancer cell lines to identify the early transcriptomic signatures of C-1305 cytotoxicity that highlight the novel pathways responsible for its biological activity. Our results demonstrate that C-1305 promotes direct microtubule stabilization as a part of its mechanism of action that leads to apoptosis. Furthermore, we show that C-1305 promotes G2 cell cycle arrest by modulating gene expression. The results indicate that C-1305 is the first microtubule stabilizing agent that also is a topoisomerase II inhibitor. This study provides a novel approach and methodology for delineating the antitumor mechanisms of other putative anticancer drug candidates.

Nucleotide ecto-enzyme metabolic pattern and spatial distribution in calcific aortic valve disease; its relation to pathological changes and clinical presentation

BACKGROUND

Extracellular nucleotide metabolism contributes to chronic inflammation, cell differentiation, and tissue mineralization by controlling nucleotide and adenosine concentrations and hence its purinergic effects. This study investigated location-specific changes of extracellular nucleotide metabolism in aortic valves of patients with calcific aortic valve disease (CAVD). Individual ecto-enzymes and adenosine receptors involved were analyzed together with correlation with CAVD severity and risk factors.

RESULTS

Nucleotide and adenosine degradation rates were adversely modified on the aortic surface of stenotic valve as compared to ventricular side, including decreased ATP removal (1.25 ± 0.35 vs. 2.24 ± 0.61 nmol/min/cm2) and adenosine production (1.32 ± 0.12 vs. 2.49 ± 0.28 nmol/min/cm2) as well as increased adenosine deamination (1.28 ± 0.31 vs. 0.67 ± 0.11 nmol/min/cm2). The rates of nucleotide to adenosine conversions were lower, while adenosine deamination was higher on the aortic sides of stenotic vs. non-stenotic valve. There were no differences in extracellular nucleotide metabolism between aortic and ventricular sides of non-stenotic valves. Furthermore, nucleotide degradation rates, measured on aortic side in CAVD (n = 62), negatively correlated with echocardiographic and biochemical parameters of disease severity (aortic jet velocity vs. ATP hydrolysis: r = - 0.30, p < 0.05; vs. AMP hydrolysis: r = - 0.44, p < 0.001; valvular phosphate concentration vs. ATP hydrolysis: r = - 0.26, p < 0.05; vs. AMP hydrolysis: r = - 0.25, p = 0.05) while adenosine deamination showed positive correlation trend with valvular phosphate deposits (r = 0.23, p = 0.07). Nucleotide and adenosine conversion rates also correlated with CAVD risk factors, including hyperlipidemia (AMP hydrolysis vs. serum LDL cholesterol: r = - 0.28, p = 0.05; adenosine deamination vs. total cholesterol: r = 0.25, p = 0.05; LDL cholesterol: r = 0.28, p < 0.05; triglycerides: r = 0.32, p < 0.05), hypertension (adenosine deamination vs. systolic blood pressure: r = 0.28, p < 0.05) and thrombosis (ATP hydrolysis vs. prothrombin time: r = - 0.35, p < 0.01). Functional assays as well as histological and immunofluorescence, flow cytometry and RT-PCR studies identified all major ecto-enzymes engaged in nucleotide metabolism in aortic valves that included ecto-nucleotidases, alkaline phosphatase, and ecto-adenosine deaminase. We have shown that changes in nucleotide-converting ecto-enzymes were derived from their altered activities on valve cells and immune cell infiltrate. We have also demonstrated a presence of A1, A2a and A2b adenosine receptors with diminished expression of A2a and A2b in stenotic vs. non-stenotic valves. Finally, we revealed that augmenting adenosine effects by blocking adenosine deamination with deoxycoformycin decreased aortic valve thickness and reduced markers of calcification via adenosine-dependent pathways in a mouse model of CAVD.

CONCLUSIONS

This work highlights profound changes in extracellular nucleotide and adenosine metabolism in CAVD. Altered extracellular nucleotide hydrolysis and degradation of adenosine in stenotic valves may affect purinergic responses to support a pro-stenotic milieu and valve calcification. This emphasizes a potential mechanism and target for prevention and therapy. .

Genome-wide mRNA profiling identifies RCAN1 and GADD45A as regulators of the transitional switch from survival to apoptosis during ER stress

Endoplasmic reticulum (ER) stress conditions promote a cellular adaptive mechanism called the unfolded protein response (UPR) that utilizes three stress sensors, inositol-requiring protein 1, protein kinase RNA-like ER kinase, and activating transcription factor 6. These sensors activate a number of pathways to reduce the stress and facilitate cell survival. While much is known about the mechanisms involved that modulate apoptosis during chronic stress, less is known about the transition between the prosurvival and proapoptotic factors that determine cell fate. Here, we employed a genetic screen that utilized three different pharmacological stressors to induce ER stress in a human-immortalized airway epithelial cell line, immortalized human bronchial epithelial cells. We followed the stress responses over an 18-h time course and utilized real-time monitoring of cell survival, next-generation sequencing, and quantitative real-time PCR to identify and validate genes that were upregulated with all three commonly employed ER stressors, inhibitor of calpain 1, tunicamycin, and thapsigargin. growth arrest and DNA damage-inducible alpha (GADD45A), a proapoptotic factor, and regulator of calcineurin 1 (RCAN1) mRNAs were identified and verified by showing that small interfering RNA (siRNA) knockdown of GADD45A decreased CCAAT-enhancer-binding protein homologous protein (a.k.a DDIT3), BCL2-binding component 3 (a.k.a. BBC3), and phorbol-12-myristate-13-acetate-induced protein 1 expression, 3 proapoptotic factors, and increased cell viability during ER stress conditions, whereas siRNA knockdown of RCAN1 dramatically decreased cell viability. These results suggest that the relative levels of these two genes regulate cell fate decisions during ER stress independent of the type of ER stressor.

miR-34c-5p modulates X-box-binding protein 1 (XBP1) expression during the adaptive phase of the unfolded protein response

During endoplasmic reticulum (ER) stress conditions, an adaptive signaling network termed the unfolded protein response (UPR) is activated. The UPR's function is to increase ER protein-folding capacity in order to attenuate ER stress, restore ER homeostasis, and, most importantly, promote cell survival. X-box-binding protein 1 (XBP1) is one component of the UPR and is a proadaptive transcription factor that is subject to transcriptional, post-transcriptional, and post-translational control. In the present study, we identified a post-transcriptional mechanism mediated by miR-34c-5p that governs the expression of both the spliced (active) and unspliced (latent) forms of XBP1 mRNAs. We showed that miR-34c-5p directly attenuates spliced XBP1 (XBP1s) mRNA levels during ER stress and thus regulates the proadaptive component of the UPR that is mediated by XBP1s without interfering with the induction of apoptotic responses.-Bartoszewska, S., Cabaj, A., Dąbrowski, M., Collawn, J. F., Bartoszewski, R. miR-34c-5p modulates X-box-binding protein 1 (XBP1) expression during the adaptive phase of the unfolded protein response.

Hesperidin as a Neuroprotective Agent: A Review of Animal and Clinical Evidence

Neuroprotection is the preservation of function and networks of neural tissues from damages caused by various agents, as well as neurodegenerative diseases such as Parkinson's, Alzheimer's, Huntington's diseases, and multiple sclerosis. Hesperidin, a flavanone glycoside, is a natural phenolic compound with a wide range of biological effects. Mounting evidence has demonstrated that hesperidin possesses inhibitory effect against development of neurodegenerative diseases. Our review discusses neuropharmacological mechanisms for preventive and therapeutic effects of hesperidin in neurodegenerative diseases. In addition, the review examines clinical evidence confirming its neuroprotective function. Various cellular and animal models specific to neurodegenerative diseases have been conducted to evaluate the underlying neuropharmacological mechanisms of hesperidin. Neuroprotective potential of this flavonoid is mediated by improvement of neural growth factors and endogenous antioxidant defense functions, diminishing neuro-inflammatory and apoptotic pathways. Despite the various preclinical studies on the role of hesperidin in the neurodegenerative diseases, less is known about its definite effect on humans. A limited number of clinical trials showed that hesperidin-enriched dietary supplements can significantly improve cerebral blood flow, cognition, and memory performance. Further clinical trials are also required for confirming neuroprotective efficacy of this natural flavonoid and evaluating its safety profile.

Inhibition of LPS-stimulated ecto-adenosine deaminase attenuates endothelial cell activation

Vascular inflammation is an important factor in the pathophysiology of cardiovascular diseases, such as atherosclerosis. Changes in the extracellular nucleotide and in particular adenosine catabolism may alter a chronic inflammation and endothelial activation. This study aimed to evaluate the relation between vascular ecto-adenosine deaminase (eADA) activity and endothelial activation in humans and to analyze the effects of LPS-mediated inflammation on this activity as well as mechanisms of its increase. Moreover, we investigated a therapeutic potential of ADA inhibition by deoxycofromycin (dCF) for endothelial activation. We demonstrated a positive correlation of vascular eADA activity and ADA1 mRNA expression with endothelial activation parameters in humans with atherosclerosis. The activation of vascular eADA was also observed under LPS stimulation in vivo along with endothelial activation, an increase in markers of inflammation and alterations in the lipid profile of a rat model. Ex vivo and in vitro studies on human specimen demonstrated that at an early stage of vascular pathology, eADA activity originated from activated endothelial cells, while at later stages also from an inflammatory infiltrate. We proposed that LPS-stimulated increase in endothelial adenosine deaminase activity could be a result of IL-6/JAK/STAT pathway activation, since the lack of IL-6 in mice was associated with lower vascular and plasma eADA activities. Furthermore, the inhibitors of JAK/STAT pathway decreased LPS-stimulated adenosine deaminase activity in endothelial cells. We demonstrated that cell surface eADA activity could be additionally regulated by transcytosis pathways, as exocytosis inhibitors including lipid raft inhibitor, methyl-β-cyclodextrin decreased LPS-induced eADA activity. This suggests that cholesterol-dependent protein externalization mediated by lipid rafts could be an important factor in the eADA increase. Moreover, endocytosis inhibitors and exocytosis activators increased this activity on the cell surface. Furthermore, the inhibition of adenosine deaminase in endothelial cells in vitro attenuated LPS-mediated IL-6 release and soluble ICAM-1 and VCAM-1 concentration in the incubation medium through the restoration of the extracellular adenosine pool and adenosine receptor-dependent pathways. This study demonstrated that the vascular endothelial eADA activity remains under control of inflammatory mediators acting through JAK/STAT pathway that could be further modified by dyslipidemic-dependent exocytosis and transcytosis pathways. Inhibition of eADA blocked endothelial activation suggesting a crucial role of this enzyme in the control of vascular inflammation. This supports the concept of eADA targeted vascular protection therapy.

Application of Real-Time Cell Electronic Analysis System in Modern Pharmaceutical Evaluation and Analysis

Objective: We summarized the progress of the xCELLigence real-time cell analysis (RTCA) technology application in recent years for the sake of enriching and developing the application of RTCA in the field of Chinese medicine. Background: The RTCA system is an established electronic cellular biosensor. This system uses micro-electronic biosensor technology that is confirmed for real-time, label-free, dynamic and non-offensive monitoring of cell viability, migration, growth, spreading, and proliferation. Methods: We summarized the relevant experiments and literature of RTCA technology from the principles, characteristics, applications, especially from the latest application progress. Results and conclusion: RTCA is attracting more and more attention. Now it plays an important role in drug screening, toxicology, Chinese herbal medicine and so on. It has wide application prospects in the area of modern pharmaceutical evaluation and analysis.

PIWI proteins contribute to apoptosis during the UPR in human airway epithelial cells

Small noncoding microRNAs (miRNAs) post-transcriptionally regulate a large portion of the human transcriptome. miRNAs have been shown to play an important role in the unfolded protein response (UPR), a cellular adaptive mechanism that is important in alleviating endoplasmic reticulum (ER) stress and promoting cell recovery. Another class of small noncoding RNAs, the Piwi-interacting RNAs (piRNAs) together with PIWI proteins, was originally shown to play a role as repressors of germline transposable elements. More recent studies, however, indicate that P-element induced WImpy proteins (PIWI proteins) and piRNAs also regulate mRNA levels in somatic tissues. Using genome-wide small RNA next generation sequencing, cell viability assays, and caspase activity assays in human airway epithelial cells, we demonstrate that ER stress specifically up-regulates total piRNA expression profiles, and these changes correlate with UPR-induced apoptosis as shown by up-regulation of two pro-apoptotic factor mRNAs, CHOP and NOXA. Furthermore, siRNA knockdown of PIWIL2 and PIWIL4, two proteins involved in piRNA function, attenuates UPR-related cell death, inhibits piRNA expression, and inhibits the up-regulation of CHOP and NOXA mRNA expression. Hence, we provide evidence that PIWIL2 and PIWIL4 proteins, and potentially the up-regulated piRNAs, constitute a novel epigenetic mechanism that control cellular fate during the UPR.

Improving the biopharmaceutical attributes of mangiferin using vitamin E-TPGS co-loaded self-assembled phosholipidic nano-mixed micellar systems

The current research work encompasses the development, characterization, and evaluation of self-assembled phospholipidic nano-mixed miceller system (SPNMS) of a poorly soluble BCS Class IV xanthone bioactive, mangiferin (Mgf) functionalized with co-delivery of vitamin E TPGS. Systematic optimization using I-optimal design yielded self-assembled phospholipidic nano-micelles with a particle size of < 60 nm and > 80% of drug release in 15 min. The cytotoxicity and cellular uptake studies performed using MCF-7 and MDA-MB-231 cell lines demonstrated greater kill and faster cellular uptake. The ex vivo intestinal permeability revealed higher lymphatic uptake, while in situ perfusion and in vivo pharmacokinetic studies indicated nearly 6.6- and 3.0-folds augmentation in permeability and bioavailability of Mgf. In a nutshell, vitamin E functionalized SPNMS of Mgf improved the biopharmaceutical performance of Mgf in rats for enhanced anticancer potency.

Pharmacoinformatics approach for the identification of Polo-like kinase-1 inhibitors from natural sources as anti-cancer agents

Polo-like kinase-1 (PLK-1) plays a key role in cell cycle progression during mitosis. Overexpression/dysfunction of PLK-1 is directly associated with cancerous transformation and has been reported in different cancer types. Here, we employed high throughput virtual screening and molecular docking to screen Selleck's natural compound library against PLK-1 kinase domain. We have identified eight bioactive compounds (Apigenin, Dihydromyricetin, Diosmetin, Hesperidin, Hesperitin, Naringenin, Phlorizi, and Quercetin) as the potential inhibitors of PLK-1. Further investigation through Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) calculations and 15 ns molecular dynamics simulation revealed that hesperidin formed the most stable complex with PLK-1 kinase domain. Altogether, our results indicate that hesperidin interacted strongly with the key residues of the PLK-1 active site (such as Leu59, Lys61, Lys82, Cys133, Asn181, Asp194, Leu59, Cys67, Ala80, Val114, Leu130, Leu132, Cys133, Leu139, Phe183, and Phe195) through hydrogen bonding and hydrophobic interactions. The Hesperidin-PLK-1 complex was stabilized by Gibb's free energy of -13.235 kcal/mol which corresponded to the binding affinity of 5.095 × 109 M-1. This is the first study wherein hesperidin has been identified as a potential inhibitor of PLK-1. Further design and optimization of the hesperidin scaffold as an inhibitor of PLK-1 kinase domain is highly recommended.

Cervical cancer stem-like cells: systematic review and identification of reference genes for gene expression

Cervical cancer is the fourth most common cancer affecting women worldwide. Among many factors, the presence of cancer stem cells, a subpopulation of cells inside the tumor, has been associated with a worse prognosis. Considering the importance of gene expression studies to understand the biology of cervical cancer stem cells (CCSC), this work identifies stable reference genes for cervical cancer cell lines SiHa, HeLa, and ME180 as well as their respective cancer stem-like cells. A literature review was performed to identify validated reference genes currently used to normalize RT-qPCR data in cervical cancer cell lines. Then, cell lines were cultured in regular monolayer or in a condition that favors tumor sphere formation. RT-qPCR was performed using five reference genes: ACTB, B2M, GAPDH, HPRT1, and TBP. Stability was assessed to validate the selected genes as suitable reference genes. The evaluation validated B2M, GAPDH, HPRT1, and TBP in these experimental conditions. Among them, GAPDH and TBP presented the lowest variability according to the analysis by Normfinder, Bestkeeper, and ΔCq methods, being therefore the most adequate genes to normalize the combination of all samples. These results suggest that B2M, GAPDH, HPRT1, and TBP are suitable reference genes to normalize RT-qPCR data of established cervical cancer cell lines SiHa, HeLa, and ME180 as well as their derived cancer stem-like cells. Indeed, GAPDH and TBP seem to be the most convenient choices for studying gene expression in these cells in monolayers or spheres.

miR-200b downregulates Kruppel Like Factor 2 (KLF2) during acute hypoxia in human endothelial cells

The role of microRNAs in controlling angiogenesis is recognized as a promising therapeutic target in both cancer and cardiovascular disorders. However, understanding a miRNA's pleiotropic effects on angiogenesis is a limiting factor for these types of therapeutic approaches. Using genome-wide next-generation sequencing, we examined the role of an antiangiogenic miRNA, miR-200b, in primary human endothelial cells. The results indicate that miR-200b has complex effects on hypoxia-induced angiogenesis in human endothelia and importantly, that many of the reported miR-200b effects using miRNA overexpression may not be representative of the physiological role of this miRNA. We also identified the antiangiogenic KLF2 gene as a novel target of miR-200b. Our studies indicate that the physiological changes in miR-200b levels during acute hypoxia may actually have a proangiogenic effect through Klf2 downregulation and subsequent stabilization of HIF-1 signaling. Moreover, we provide a viable approach for differentiating direct from indirect miRNA effects in order to untangle the complexity of individual miRNA networks.

miR-200b downregulates CFTR during hypoxia in human lung epithelial cells

BACKGROUND

Hypoxic conditions induce the expression of hypoxia-inducible factors (HIFs) that allow cells to adapt to the changing conditions and alter the expression of a number of genes including the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is a low abundance mRNA in airway epithelial cells even during normoxic conditions, but during hypoxia its mRNA expression decreases even further.

METHODS

In the current studies, we examined the kinetics of hypoxia-induced changes in CFTR mRNA and protein levels in two human airway epithelial cell lines, Calu-3 and 16HBE14o-, and in normal primary bronchial epithelial cells. Our goal was to examine the posttranscriptional modifications that affected CFTR expression during hypoxia. We utilized in silico predictive protocols to establish potential miRNAs that could potentially regulate CFTR message stability and identified miR-200b as a candidate molecule.

RESULTS

Analysis of each of the epithelial cell types during prolonged hypoxia revealed that CFTR expression decreased after 12 h during a time when miR-200b was continuously upregulated. Furthermore, manipulation of the miRNA levels during normoxia and hypoxia using miR-200b mimics and antagomirs decreased and increased CFTR mRNA levels, respectively, and thus established that miR-200b downregulates CFTR message levels during hypoxic conditions.

CONCLUSION

The data suggest that miR-200b may be a suitable target for modulating CFTR levels in vivo.

Hesperidin induces apoptosis and G0/G1 arrest in human non-small cell lung cancer A549 cells

Lung cancer has high incidence and mortality rates worldwide. In the present study, the mechanisms by which hesperidin decreases the viability and induces the apoptosis of human non-small cell lung cancer (NSCLC) A549 cells were investigated. Initially, MTT and flow cytometric assays were performed to evaluate the effects of hesperidin on the viability and apoptosis of A549 cells and human normal lung epithelial BEAS-2B cells. The results revealed that hesperidin has no negative effects on the human normal lung epithelial BEAS-2B cells and the viability of cells treated with various concentrations of hesperidin was inhibited in a time- and dose-dependent manner compared with the control groups. Subsequently, the expression levels of proteins involved in the mitochondria-associated apoptotic pathway were studied by western blot analysis. Hesperidin was identified to induce A549 cell apoptosis by downregulating the levels of B-cell lymphoma-2 (Bcl-2) and Bcl extra large protein and simultaneously upregulating the levels of Bcl-2-associated X protein, BH3 interacting-domain death agonist (Bid), tBid, cleaved caspase-9, cleaved caspase-3 and cleaved poly(adenosine diphosphate ribose)polymerase. The effect of hesperidin on the cell cycle was assessed by flow cytometry. Hesperidin was observed to cause G0/G1 arrest of A549 cells by decreasing the expression of cyclin D1 and increasing the expression of p21 and p53. In summary, it was demonstrated that hesperidin induced apoptosis through the mitochondrial apoptotic pathway and induced G0/G1 arrest in human NSCLC A549 cells. Therefore, hesperidin may be developed as a potential therapeutic drug for the treatment of NSCLC.

The effect of mangiferin on skin: Penetration, permeation and inhibition of ECM enzymes

Mangiferin (2-C-β-D-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone) is a polyphenol with strong antioxidant properties. Mangiferin is obtained from the mango tree (Mangifera indica L., Anacardiaceae). It has been proven that mangiferin exhibits many pharmacological activities. The aim of this study was to analyze the penetration of mangiferin into the human skin and through the skin. According to our knowledge, skin penetration and permeation studies of mangiferin have not been analyzed so far. Additionally, the influence of mangiferin on two Extracellular Matrix Enzymes (ECM): collagenase and elastase, was evaluated for the first time. It has been indicated that mangiferin is able to permeate the stratum corneum and penetrate into the epidermis and dermis in comparable amounts. For confirmation of the obtained results, fluorescence microscopy was successfully utilized. The analysis revealed the capability of mangiferin to reversibly inhibit elastase and collagenase activity. The mechanism of mangiferin interaction with both enzymes was estimated as a noncompetitive inhibition.

Posttranscriptional and transcriptional regulation of endothelial nitric-oxide synthase during hypoxia: the role of microRNAs

Understanding the cellular pathways that regulate endothelial nitric oxide (eNOS, NOS3) expression and consequently nitric oxide (NO) bioavailability during hypoxia is a necessary aspect in the development of novel treatments for cardiovascular disorders. eNOS expression and eNOS-dependent NO cellular signaling during hypoxia promote an equilibrium of transcriptional and posttranscriptional molecular mechanisms that belong to both proapoptotic and survival pathways. Furthermore, NO bioavailability results not only from eNOS levels, but also relies on the presence of eNOS substrate and cofactors, the phosphorylation status of eNOS, and the presence of reactive oxygen species (ROS) that can inactivate eNOS. Since both NOS3 levels and these signaling pathways can also be a subject of posttranscriptional modulation by microRNAs (miRNAs), this class of short noncoding RNAs contribute another level of regulation for NO bioavailability. As miRNA antagomirs or specific target protectors could be used in therapeutic approaches to regulate NO levels, either by changing NOS3 mRNA stability or through factors governing eNOS activity, it is critical to understand their role in governing eNOS activity during hypoxa. In contrast to a large number of miRNAs reported to the change eNOS expression during hypoxia, only a few miRNAs modulate eNOS activity. Furthermore, impaired miRNA biogenesis leads to NOS3 mRNA stabilization under hypoxia. Here we discuss the recent studies that define miRNAs’ role in maintaining endothelial NO bioavailability emphasizing those miRNAs that directly modulate NOS3 expression or eNOS activity.

Reuse of E-plate cell sensor arrays in the xCELLigence Real-Time Cell Analyzer

The xCELLigence Real-Time Cell Analyzer (RTCA) is a non-invasive, impedence-based biosensor system that can measure cell viability, migration, growth, spreading, and proliferation. Changes in cell morphology and behavior are continuously monitored in real time using microelectronics located in the wells of RTCA E-plates. According to the manufacturer's recommendation, E-plates are single-use and disposable. Here, we show that E-plates can be regenerated and reused several times without significantly effecting experimental results.

Mangiferin and Cancer: Mechanisms of Action

Mangiferin, a bioactive compound derived primarily from Anacardiaceae and Gentianaceae families and found in mangoes and honeybush tea, has been extensively studied for its therapeutic properties. Mangiferin has shown promising chemotherapeutic and chemopreventative potential. This review focuses on the effect of mangiferin on: (1) inflammation, with respect to NFκB, PPARү and the immune system; (2) cell cycle, the MAPK pathway G₂/M checkpoint; (3) proliferation and metastasis, and implications on β-catenin, MMPs, EMT, angiogenesis and tumour volume; (4) apoptosis, with a focus on Bax/Bcl ratios, intrinsic/extrinsic apoptotic pathways and telomerase activity; (5) oxidative stress, through Nrf2/ARE signalling, ROS elimination and catalase activity; and (6) efficacy of chemotherapeutic agents, such as oxaliplatin, etoposide and doxorubicin. In addition, the need to enhance the bioavailability and delivery of mangiferin are briefly addressed, as well as the potential for toxicity.

Hesperidin Attenuates Ultraviolet B-Induced Apoptosis by Mitigating Oxidative Stress in Human Keratinocytes

Human skin cells undergo pathophysiological processes via generation of reactive oxygen species (ROS) upon excessive exposure to ultraviolet B (UVB) radiation. This study investigated the ability of hesperidin (C₂₈H₃₄O₁₅) to prevent apoptosis due to oxidative stress generated through UVB-induced ROS. Hesperidin significantly scavenged ROS generated by UVB radiation, attenuated the oxidation of cellular macromolecules, established mitochondrial membrane polarization, and prevented the release of cytochrome c into the cytosol. Hesperidin downregulated expression of caspase-9, caspase-3, and Bcl-2-associated X protein, and upregulated expression of B-cell lymphoma 2. Hesperidin absorbed wavelengths of light within the UVB range. In summary, hesperidin shielded human keratinocytes from UVB radiation-induced damage and apoptosis via its antioxidant and UVB absorption properties.

Mangiferin: a promising anticancer bioactive

Of late, several biologically active antioxidants from natural products have been investigated by the researchers in order to combat the root cause of carcinogenesis, in other words, oxidative stress. Mangiferin, a therapeutically active C-glucosylated xanthone, is extracted from pulp, peel, seed, bark and leaf of Mangifera indica. These polyphenols of mangiferin exhibit antioxidant properties and tend to decrease the oxygen-free radicals, thereby reducing the DNA damage. Indeed, its capability to modulate several key inflammatory pathways undoubtedly helps in stalling the progression of carcinogenesis. The current review article emphasizes an updated account on the patents published on the chemopreventive action of mangiferin, apoptosis induction made on various cancer cells, along with proposed antioxidative activities and patent mapping of other important therapeutic properties. Considering it as promising polyphenol, this paper would also summarize the diverse molecular targets of mangiferin.

miR-429 regulates the transition between Hypoxia-Inducible Factor (HIF)1A and HIF3A expression in human endothelial cells

Hypoxia-inducible factors (HIF) are heterodimeric transcription factors that allow cells to adapt and survive during hypoxia. Regulation of HIF1A and HIF2A mRNA is well characterized, whereas HIF3A mRNA regulation and function are less clear. Using RNA-Seq analysis of primary human umbilical vein endothelial cells, we found two isoforms of HIF3A were expressed, HIF3A2 and HIF3A3. Comparing HIF3A expression profiles to HIF1A mRNA during 48 hours of hypoxia revealed that HIF1A message peaked at 4 hours, whereas HIF3A expression increased while HIF1A was decreasing. Given that HIF1A mRNA is regulated by miR-429, we tested miR-429 effects on both HIF3A isoforms and found that they too were regulated by miR-429. Analysis of a HIF-3 target, DNA-damage-inducible transcript 4, a key survival gene, indicated that DDIT4 mRNA is induced by HIF-3 and negatively regulated by miR-429 through miR-429’s actions on HIF3A message. This provides a compelling model for how hypoxia-induced miR-429 regulates the switch between HIF-1 adaptive responses to HIF-3 survival responses by rapidly decreasing HIF1A levels while simultaneously slowing the progression of HIF3A expression until the miR-429 levels drop below normoxic levels. Since HIF-1 drives HIF3A and miR-429 expression, this establishes a regulatory network in which miR-429 plays a pivotal role.

Systematic Development and Validation of a Thin-Layer Densitometric Bioanalytical Method for Estimation of Mangiferin Employing Analytical Quality by Design (AQbD) Approach

The present work aims at the systematic development of a simple, rapid and highly sensitive densitometry-based thin-layer chromatographic method for the quantification of mangiferin in bioanalytical samples. Initially, the quality target method profile was defined and critical analytical attributes (CAAs) earmarked, namely, retardation factor (Rf), peak height, capacity factor, theoretical plates and separation number. Face-centered cubic design was selected for optimization of volume loaded and plate dimensions as the critical method parameters selected from screening studies employing D-optimal and Plackett-Burman design studies, followed by evaluating their effect on the CAAs. The mobile phase containing a mixture of ethyl acetate : acetic acid : formic acid : water in a 7 : 1 : 1 : 1 (v/v/v/v) ratio was finally selected as the optimized solvent for apt chromatographic separation of mangiferin at 262 nm withRf 0.68 ± 0.02 and all other parameters within the acceptance limits. Method validation studies revealed high linearity in the concentration range of 50-800 ng/band for mangiferin. The developed method showed high accuracy, precision, ruggedness, robustness, specificity, sensitivity, selectivity and recovery. In a nutshell, the bioanalytical method for analysis of mangiferin in plasma revealed the presence of well-resolved peaks and high recovery of mangiferin.

Pennogenyl Saponins from Paris quadrifolia L. Induce Extrinsic and Intrinsic Pathway of Apoptosis in Human Cervical Cancer HeLa Cells

Pennogenyl saponins are the active compounds of large number of plant species and consequently many polyherbal formulations. Hence, great interest has been shown in their characterization and in the investigation of their pharmacological and biological properties, especially anticancer. This present study reports on the evaluation of cytotoxic effects and explanation of the molecular mechanisms of action of the two pennogenyl saponins (PS 1 and PS 2) isolated from Paris quadrifolia L. rhizomes on human cervical adenocarcinoma cell line HeLa. To determine the viability of the cells treated with the compounds we used real-time cell proliferation analysis and found that the pennogenyl saponins PS 1 and PS 2 strongly inhibited the tumor cells growth with IC50 values of 1.11 ± 0.04 μg/ml and 0.87 ± 0.05 μg/ml, respectively. The flow cytometry analysis indicated that the two compounds induced apoptosis in a dose-dependent manner and decreased mitochondrial membrane potential in HeLa cells in the early stage of apoptosis. Quantitative PCR and Western Blot analysis showed that the two saponins significantly increased mRNA expression of FADD and BID as well as induced caspase-8 via increased of procaspase-8 processing in the treated cells. The results of this study suggest that both the extrinsic death receptor and intrinsic mitochondrial pathways are involved in the programmed cell death.

Divide and Conquer May Not Be the Optimal Approach to Retain the Desirable Estrogenic Attributes of the Cyclopia Nutraceutical Extract, SM6Met

The genus Cyclopia, an indigenous South African fynbos plant used to prepare honeybush tea, contains phytoestrogenic compounds. An extract from C. subternata, SM6Met, displays three desirable estrogenic attributes for future development of a phytoestrogenic nutraceutical, namely, ERα antagonism, ERβ agonism, and also antagonism of E₂-induced breast cancer cell proliferation. Activity-guided fractionation of SM6Met was used in an attempt to isolate and identify compounds conferring the desirable estrogenic profile to SM6Met. Initial liquid-liquid fractionation of SM6Met yielded a polar fraction (PF) and a non-polar fraction (NPF), with the desirable estrogenic attributes retained in the NPF. Subsequent high performance counter-current chromatography (HPCCC) fractionation of the NPF yielded three fractions (F1-F3). Interestingly, the fractions revealed separation of the previously demonstrated positive estrogenic attributes of the NPF into separate fractions, with F1 and F2 acting as ERα antagonists, only F2 inducing antagonism of E₂-induced breast cancer cell proliferation and only F3 retaining robust ERβ agonist activity. In terms of major polyphenols, quantitative HPLC and liquid chromatography tandem mass spectrometry (LC-MS/MS) indicated that HPCCC fractionation resulted in a divergence of polyphenolic classes, with F1 emerging as the dihydrochalcone-rich fraction and F2 as the flavanone- and benzophenone-rich fraction, while the xanthones, flavones and phenolic acids were retained in F3. F3 was re-engineered into F3R by reassembling the major polyphenols identified in the fraction. F3R could, however, not replicate the effect of F3. In conclusion, although activity-guided fractionation results suggest that retention of all the desirable estrogenic attributes of the original SM6Met in one fraction is not an attainable goal, fractionation is a useful tool to enhance specific desirable estrogenic attributes.

The hypoxia-inducible miR-429 regulates hypoxia-inducible factor-1α expression in human endothelial cells through a negative feedback loop

Hypoxia-inducible factors (HIFs) 1 and 2 are dimeric α/β transcription factors that regulate cellular responses to low oxygen. HIF-1 is induced first, whereas HIF-2 is associated with chronic hypoxia. To determine how HIF1A mRNA, the inducible subunit of HIF-1, is regulated during hypoxia, we followed HIF1A mRNA levels in primary HUVECs over 24 hours using quantitative PCR. HIF1A and VEGF A (VEGFA) mRNA, a transcriptional target of HIF-1, increased ∼ 2.5- and 8-fold at 2-4 hours, respectively. To determine how the mRNAs were regulated, we identified a microRNA (miRNA), miR-429, that destabilized HIF1A message and decreased VEGFA mRNA by inhibiting HIF1A. Target protector analysis, which interferes with miRNA-mRNA complex formation, confirmed that miR-429 targeted HIF1A message. Desferoxamine treatment, which inhibits the hydroxylases that promote HIF-1α protein degradation, stabilized HIF-1 activity during normoxic conditions and elevated miR-429 levels, demonstrating that HIF-1 promotes miR-429 expression. RNA-sequencing-based transcriptome analysis indicated that inhibition of miRNA-429 in HUVECs up-regulated 209 mRNAs, a number of which regulate angiogenesis. The results demonstrate that HIF-1 is in a negative regulatory loop with miR-429, that miR-429 attenuates HIF-1 activity by decreasing HIF1A message during the early stages of hypoxia before HIF-2 is activated, and this regulatory network helps explain the HIF-1 transition to HIF-2 during chronic hypoxia in endothelial cells.