1
|
Targeting Chaperone/Co-Chaperone Interactions with Small Molecules: A Novel Approach to Tackle Neurodegenerative Diseases. Cells 2021; 10:cells10102596. [PMID: 34685574 PMCID: PMC8534281 DOI: 10.3390/cells10102596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/23/2021] [Accepted: 09/25/2021] [Indexed: 01/07/2023] Open
Abstract
The dysfunction of the proteostasis network is a molecular hallmark of neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. Molecular chaperones are a major component of the proteostasis network and maintain cellular homeostasis by folding client proteins, assisting with intracellular transport, and interfering with protein aggregation or degradation. Heat shock protein 70 kDa (Hsp70) and 90 kDa (Hsp90) are two of the most important chaperones whose functions are dependent on ATP hydrolysis and collaboration with their co-chaperones. Numerous studies implicate Hsp70, Hsp90, and their co-chaperones in neurodegenerative diseases. Targeting the specific protein–protein interactions between chaperones and their particular partner co-chaperones with small molecules provides an opportunity to specifically modulate Hsp70 or Hsp90 function for neurodegenerative diseases. Here, we review the roles of co-chaperones in Hsp70 or Hsp90 chaperone cycles, the impacts of co-chaperones in neurodegenerative diseases, and the development of small molecules modulating chaperone/co-chaperone interactions. We also provide a future perspective of drug development targeting chaperone/co-chaperone interactions for neurodegenerative diseases.
Collapse
|
2
|
Serwetnyk MA, Blagg BS. The disruption of protein-protein interactions with co-chaperones and client substrates as a strategy towards Hsp90 inhibition. Acta Pharm Sin B 2021; 11:1446-1468. [PMID: 34221862 PMCID: PMC8245820 DOI: 10.1016/j.apsb.2020.11.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/12/2020] [Accepted: 11/13/2020] [Indexed: 12/16/2022] Open
Abstract
The 90-kiloDalton (kD) heat shock protein (Hsp90) is a ubiquitous, ATP-dependent molecular chaperone whose primary function is to ensure the proper folding of several hundred client protein substrates. Because many of these clients are overexpressed or become mutated during cancer progression, Hsp90 inhibition has been pursued as a potential strategy for cancer as one can target multiple oncoproteins and signaling pathways simultaneously. The first discovered Hsp90 inhibitors, geldanamycin and radicicol, function by competitively binding to Hsp90's N-terminal binding site and inhibiting its ATPase activity. However, most of these N-terminal inhibitors exhibited detrimental activities during clinical evaluation due to induction of the pro-survival heat shock response as well as poor selectivity amongst the four isoforms. Consequently, alternative approaches to Hsp90 inhibition have been pursued and include C-terminal inhibition, isoform-selective inhibition, and the disruption of Hsp90 protein-protein interactions. Since the Hsp90 protein folding cycle requires the assembly of Hsp90 into a large heteroprotein complex, along with various co-chaperones and immunophilins, the development of small molecules that prevent assembly of the complex offers an alternative method of Hsp90 inhibition.
Collapse
Key Words
- ADP, adenosine diphosphate
- ATP, adenosine triphosphate
- Aha1, activator of Hsp90 ATPase homologue 1
- CTD, C-terminal domain
- Cdc37, cell division cycle 37
- Disruptors
- Grp94, 94-kD glucose-regulated protein
- HIF-1α, hypoxia-inducing factor-1α
- HIP, Hsp70-interaction protein
- HOP, Hsp70‒Hsp90 organizing protein
- HSQC, heteronuclear single quantum coherence
- Her-2, human epidermal growth factor receptor-2
- Hsp90
- Hsp90, 90-kD heat shock protein
- MD, middle domain
- NTD, N-terminal domain
- Natural products
- PPI, protein−protein interaction
- Peptidomimetics
- Protein−protein interactions
- SAHA, suberoylanilide hydroxamic acid
- SAR, structure–activity relationship
- SUMO, small ubiquitin-like modifier
- Small molecules
- TPR2A, tetratricopeptide-containing repeat 2A
- TRAP1, Hsp75tumor necrosis factor receptor associated protein 1
- TROSY, transverse relaxation-optimized spectroscopy
- hERG, human ether-à-go-go-related gene
Collapse
|
3
|
Li P, Liu L, Huang S, Zhang Y, Xu J, Zhang Z. Anti-cancer Effects of a Neutral Triterpene Fraction from Ganoderma lucidum and its Active Constituents on SW620 Human Colorectal Cancer Cells. Anticancer Agents Med Chem 2020; 20:237-244. [DOI: 10.2174/1871520619666191015102442] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 03/26/2019] [Accepted: 09/25/2019] [Indexed: 01/08/2023]
Abstract
Background:
Ganoderma lucidum (Leyss. ex Fr.) Karst. (G. lucidum, GL) belongs to the family of
Ganodermataceae (Basidiomycetes), and possesses activities including antitumor, antimicrobial, antiviral, and
antiaging activities. Triterpenoids are typical chemical constituents in G. lucidum, and play an important role in
the anti-cancer effects. According to the substituent group at the carbon 26 position, GL total triterpenes fraction
can be divided into two types, Neutral Triterpene Fraction (NTF) and an Acidic Triterpene Fraction (ATF). The
anti-cancer effects of total triterpenes fraction and total acidic triterpene fraction extracted from G. lucidum have
been widely known in vivo and in vitro, whereas few have focused on total neutral triterpene fraction.
Objective:
The aim of this study was to evaluate the anti-cancer effects of NTF extracted from G. lucidum in
vitro and in vivo and explore its anti-cancer active constituents on SW620 human colorectal cancer cells.
Methods:
NTF and ATF were extracted from the dry fruiting body of G. lucidum by impregnation method with
90% ethanol, and further isolated by using alkaline extraction and acid precipitation method. The total triterpenoid
content of NTF and ATF was determined by using ultraviolet-visible spectrophotometry. The cytotoxic
effects on human colon cancer cells SW480, SW620, SW1116, and mouse embryonic fibroblast cell line
NIH3T3 were evaluated by using the MTT method. The anti-cancer activity of NTF in vivo was evaluated in
Athymic nude mice against SW620 cells. An activity-guided separation and purification process were used to
identify the anti-cancer active constituents of NTF by column and preparative high-performance liquid chromatography.
Structures of the constituents were confirmed by 1H-NMR, 13C-NMR and MS. Protein expression was
performed by Western blotting.
Results:
The percentage of total triterpenoids was 46.7% and 57.6% in ATF and NTF, respectively. Both fractions
could reduce the viability of SW480, SW620, and SW1116 cells in vitro, whereby NTF exhibited a
stronger effect than ATF. NTF markedly inhibited the growth of SW620 cell xenografts in mice at doses (250,
500mg/kg) during the treatment. Furthermore, a new garnoderic alcohol, named as ethyl ganoderate A and eight
known ganoderic alcohols were isolated and identified from NTF by a bioassay-guided separation process. All
of these compounds possessed anti-cancer activities against SW620 cells in vitro. As a representative ganoderma
alcohol, ganodermanondiol significantly reduced the viability of SW620 cells through the induction of
apoptosis, which was associated with the upregulated the levels of cleaved-poly (ADP-ribose) polymerase
(PARP), cleaved-caspase-3, and -9. In addition, ganodermanondiol showed low cytotoxic activity against normal
NIH3T3 cells.
Conclusion:
NTF are potential anti-cancer agents against colon cancer and the active constituents may be ganoderic
alcohols whose inhibitory mechanism of anti-cancer action may be related to the activation of a mitochondrial-
dependent pathway.
Collapse
Affiliation(s)
- Peng Li
- Department of Natural Medicine, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Lingxue Liu
- Department of Natural Medicine, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Sheng Huang
- Department of Natural Medicine, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Yonghong Zhang
- Department of Natural Medicine, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Jianhua Xu
- Fujian Key Laboratory of Natural Medicine Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Zhiqiang Zhang
- Fujian Key Laboratory of Natural Medicine Pharmacology, School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| |
Collapse
|
4
|
Lines KE, Filippakopoulos P, Stevenson M, Müller S, Lockstone HE, Wright B, Knapp S, Buck D, Bountra C, Thakker RV. Effects of epigenetic pathway inhibitors on corticotroph tumour AtT20 cells. Endocr Relat Cancer 2020; 27:163-174. [PMID: 31935194 PMCID: PMC7040567 DOI: 10.1530/erc-19-0448] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022]
Abstract
Medical treatments for corticotrophinomas are limited, and we therefore investigated the effects of epigenetic modulators, a new class of anti-tumour drugs, on the murine adrenocorticotropic hormone (ACTH)-secreting corticotrophinoma cell line AtT20. We found that AtT20 cells express members of the bromo and extra-terminal (BET) protein family, which bind acetylated histones, and therefore, studied the anti-proliferative and pro-apoptotic effects of two BET inhibitors, referred to as (+)-JQ1 (JQ1) and PFI-1, using CellTiter Blue and Caspase Glo assays, respectively. JQ1 and PFI-1 significantly decreased proliferation by 95% (P < 0.0005) and 43% (P < 0.0005), respectively, but only JQ1 significantly increased apoptosis by >50-fold (P < 0.0005), when compared to untreated control cells. The anti-proliferative effects of JQ1 and PFI-1 remained for 96 h after removal of the respective compound. JQ1, but not PFI-1, affected the cell cycle, as assessed by propidium iodide staining and flow cytometry, and resulted in a higher number of AtT20 cells in the sub G1 phase. RNA-sequence analysis, which was confirmed by qRT-PCR and Western blot analyses, revealed that JQ1 treatment significantly altered expression of genes involved in apoptosis, such as NFκB, and the somatostatin receptor 2 (SSTR2) anti-proliferative signalling pathway, including SSTR2. JQ1 treatment also significantly reduced transcription and protein expression of the ACTH precursor pro-opiomelanocortin (POMC) and ACTH secretion by AtT20 cells. Thus, JQ1 treatment has anti-proliferative and pro-apoptotic effects on AtT20 cells and reduces ACTH secretion, thereby indicating that BET inhibition may provide a novel approach for treatment of corticotrophinomas.
Collapse
Affiliation(s)
- K E Lines
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
| | | | - M Stevenson
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
| | - S Müller
- Structural Genomics Consortium, Buchmann Institute for Life Sciences, Goethe-University Frankfurt, Frankfurt, Germany
| | - H E Lockstone
- Oxford Genomics Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - B Wright
- Oxford Genomics Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - S Knapp
- Structural Genomics Consortium, Buchmann Institute for Life Sciences, Goethe-University Frankfurt, Frankfurt, Germany
- Institute of Pharmaceutical Chemistry, Goethe-University Frankfurt, Frankfurt, Germany
| | - D Buck
- Oxford Genomics Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - C Bountra
- Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - R V Thakker
- OCDEM, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK
- Correspondence should be addressed to R V Thakker:
| |
Collapse
|
5
|
Reduction of cardiac TGFβ-mediated profibrotic events by inhibition of Hsp90 with engineered protein. J Mol Cell Cardiol 2018; 123:75-87. [PMID: 30193958 DOI: 10.1016/j.yjmcc.2018.08.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/06/2018] [Accepted: 08/17/2018] [Indexed: 11/22/2022]
Abstract
Myocardial fibroblast activation coupled with extracellular matrix production is a pathological signature of myocardial fibrosis and is governed mainly by transforming growth factor TGFβ-Smad2/3 signaling. Targeting the ubiquitous TGFβ leads to cellular homeostasis deregulation with adverse consequences. We previously showed the anti-fibrotic effects upon downregulation of 90-kDa heat shock protein (Hsp90), a chaperone that associates to the TGFβ signaling cascade. In the present study, we use a fluorescent-labeled Hsp90 protein inhibitor (CTPR390-488) with specific Hsp90 binding properties to reduce myocardial pro-fibrotic events in vitro and in vivo. The mechanism of action involves the disruption of TGFβRI-Hsp90 complex, resulting in a decrease in TGFβ signaling and reduction in extracellular matrix collagen. In vivo, decreased myocardial collagen deposition was observed upon CTPR390-488 treatment in a pro-fibrotic mouse model. This is the first study demonstrating the ability of an engineered Hsp90 protein inhibitor to block collagen expression, reduce the motility of myocardial TGFβ-activated fibroblasts and ameliorate angiotensin-II induced cardiac myocardial fibrosis in vivo.
Collapse
|
6
|
Tanabe N, Kuboyama T, Tohda C. Matrine Directly Activates Extracellular Heat Shock Protein 90, Resulting in Axonal Growth and Functional Recovery in Spinal Cord Injured-Mice. Front Pharmacol 2018; 9:446. [PMID: 29867458 PMCID: PMC5949560 DOI: 10.3389/fphar.2018.00446] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 04/17/2018] [Indexed: 01/28/2023] Open
Abstract
After spinal cord injury (SCI), reconstruction of neuronal tracts is very difficult because an inhibitory scar is formed at the lesion site, in which several axonal growth inhibitors, such as chondroitin sulfate proteoglycans (CSPG), accumulate. We previously found that matrine, a major alkaloid in Sophora flavescens, enhanced axonal growth in neurons seeded on CSPG coating. The aims of this study were to investigate therapeutic effects of matrine in SCI mice and to clarify the underlying mechanism. Matrine was orally administered to contusion SCI mice. In the matrine-treated mice, motor dysfunction of the hindlimbs was improved, and the density of 5-HT-positive tracts was increased in the injured spinal cord. We explored putative direct binding proteins of matrine in cultured neurons using drug affinity responsive target stability (DARTS). As a result, heat shock protein 90 (HSP90) was identified, and matrine enhanced HSP90 chaperon activity. We then presumed that extracellular HSP90 is a matrine-targeting signaling molecule, and found that specific blocking of extracellular HSP90 by a neutralizing antibody completely diminished matrine-induced axonal growth and SCI amelioration. Our results suggest that matrine enhances axonal growth and functional recovery in SCI mice by direct activation of extracellular HSP90. Matrine could be a significant candidate for therapeutic drugs for SCI with a novel mechanism.
Collapse
Affiliation(s)
- Norio Tanabe
- Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Tomoharu Kuboyama
- Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Chihiro Tohda
- Division of Neuromedical Science, Department of Bioscience, Institute of Natural Medicine, University of Toyama, Toyama, Japan
| |
Collapse
|
7
|
Lines KE, Stevenson M, Filippakopoulos P, Müller S, Lockstone HE, Wright B, Grozinsky-Glasberg S, Grossman AB, Knapp S, Buck D, Bountra C, Thakker RV. Epigenetic pathway inhibitors represent potential drugs for treating pancreatic and bronchial neuroendocrine tumors. Oncogenesis 2017; 6:e332. [PMID: 28504695 PMCID: PMC5523063 DOI: 10.1038/oncsis.2017.30] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 03/24/2017] [Accepted: 03/28/2017] [Indexed: 02/06/2023] Open
Abstract
Cancer is associated with alterations in epigenetic mechanisms such as histone modifications and methylation of DNA, and inhibitors targeting epigenetic mechanisms represent a novel class of anti-cancer drugs. Neuroendocrine tumors (NETs) of the pancreas (PNETs) and bronchus (BNETs), which may have 5-year survivals of <50% and as low as 5%, respectively, represent targets for such drugs, as >40% of PNETs and ~35% of BNETs have mutations of the multiple endocrine neoplasia type 1 (MEN1) gene, which encodes menin that modifies histones by interacting with histone methyltransferases. We assessed 9 inhibitors of epigenetic pathways, for their effects on proliferation, by CellTiter Blue assay, and apoptosis, by CaspaseGlo assay, using 1 PNET and 2 BNET cell lines. Two inhibitors, referred to as (+)-JQ1 (JQ1) and PFI-1, targeting the bromo and extra terminal (BET) protein family which bind acetylated histone residues, were most effective in decreasing proliferation (by 40-85%, P<0.001) and increasing apoptosis (by 2-3.6 fold, P<0.001) in all 3 NET cell lines. The anti-proliferative effects of JQ1 and PFI-1 remained present for at least 48 hours after removal of the compound. JQ1, but not PFI-1, had cell cycle effects, assessed by propidium iodide staining and flow cytometry, resulting in increased and decreased proportions of NET cells in G1, and S and G2 phases, respectively. RNA Sequencing analysis revealed that these JQ1 effects were associated with increased histone 2B expression, and likely mediated through altered activity of bromodomain-containing (Brd) proteins. Assessment of JQ1 in vivo, using a pancreatic beta cell-specific conditional Men1 knockout mouse model that develops PNETs, revealed that JQ1 significantly reduced proliferation (by ~50%, P<0.0005), assessed by bromodeoxyuridine incorporation, and increased apoptosis (by ~3 fold, P<0.0005), assessed by terminal deoxynucleotidyl transferase dUTP nick end labelling, of PNETs. Thus, our studies demonstrate that BET protein inhibitors may provide new treatments for NETs.
Collapse
Affiliation(s)
- K E Lines
- Academic Endocrine Unit, OCDEM, University of Oxford, Churchill Hospital, Headington, Oxford, UK
| | - M Stevenson
- Academic Endocrine Unit, OCDEM, University of Oxford, Churchill Hospital, Headington, Oxford, UK
| | - P Filippakopoulos
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Headington, Oxford, UK
| | - S Müller
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Headington, Oxford, UK
| | - H E Lockstone
- Oxford Genomics Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - B Wright
- Oxford Genomics Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - S Grozinsky-Glasberg
- Neuroendocrine Tumor Unit, Endocrinology & Metabolism Service, Department of Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - A B Grossman
- Academic Endocrine Unit, OCDEM, University of Oxford, Churchill Hospital, Headington, Oxford, UK
| | - S Knapp
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Headington, Oxford, UK
- Institute for Pharmaceutical Chemistry, Johann Wolfgang Goethe-University and Buchmann Institute for Molecular Life Sciences, Max-von-Laue-Strasse 9, Frankfurt am Main, Jerusalem, Germany
| | - D Buck
- Oxford Genomics Centre, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - C Bountra
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Headington, Oxford, UK
| | - R V Thakker
- Academic Endocrine Unit, OCDEM, University of Oxford, Churchill Hospital, Headington, Oxford, UK
| |
Collapse
|
8
|
Extracellular heat shock protein 90 binding to TGFβ receptor I participates in TGFβ-mediated collagen production in myocardial fibroblasts. Cell Signal 2016; 28:1563-79. [PMID: 27418101 DOI: 10.1016/j.cellsig.2016.07.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/29/2016] [Accepted: 07/08/2016] [Indexed: 12/14/2022]
Abstract
The pathological remodeling heart shows an increase in left ventricular mass and an excess of extracellular matrix deposition that can over time cause heart failure. Transforming growth factor β (TGFβ) is the main cytokine controlling this process. The molecular chaperone heat shock protein 90 (Hsp90) has been shown to play a critical role in TGFβ signaling by stabilizing the TGFβ signaling cascade. We detected extracellular Hsp90 in complex with TGFβ receptor I (TGFβRI) in fibroblasts and determined a close proximity between both proteins suggesting a potential physical interaction between the two at the plasma membrane. This was supported by in silico studies predicting Hsp90 dimers and TGFβRI extracellular domain interaction. Both, Hsp90aa1 and Hsp90ab1 isoforms participate in TGFβRI complex. Extracellular Hsp90 inhibition lessened the yield of collagen production as well as the canonical TGFβ signaling cascade, and collagen protein synthesis was drastically reduced in Hsp90aa1 KO mice. These observations together with the significant increase in activity of Hsp90 at the plasma membrane pointed to a functional cooperative partnership between Hsp90 and TGFβRI in the fibrotic process. We propose that a surface population of Hsp90 extracellularly binds TGFβRI and this complex behaves as an active participant in collagen production in TGFβ-activated fibroblasts. We also offer an in vivo insight into the role of Hsp90 and its isoforms during cardiac remodeling in murine aortic banding model suffering from pathological cardiac remodeling and detect circulating Hsp90 overexpressed in remodeling mice.
Collapse
|
9
|
Ma Y, Li W, Yin Y, Li W. AST IV inhibits H₂O₂-induced human umbilical vein endothelial cell apoptosis by suppressing Nox4 expression through the TGF-β1/Smad2 pathway. Int J Mol Med 2015; 35:1667-74. [PMID: 25891879 DOI: 10.3892/ijmm.2015.2188] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/08/2015] [Indexed: 11/06/2022] Open
Abstract
Endothelial cell apoptosis plays an important role in the pathophysiological mechanisms of vascular complications in diabetes mellitus (DM). NADPH oxidase 4 (Nox4)-dependent reactive oxygen species (ROS) aggregation is the main cause of vascular endothelial cell apoptosis. The transforming growth factor-β1 (TGF-β1)/Smad2 signaling pathway is involved in the apoptosis of several types of cells. However, the association between vascular endothelial cell apoptosis and Nox4, and the involvement of the TGF-β1/Smad2 signaling pathway in vascular endothelial cell apoptosis remain unclear. In the present study, we aimed to investigate the role of Nox4-dependent ROS production and to determine the involvement of the TGF-β1/Smad2 signaling pathway in endothelial cell apoptosis induced by oxidative stress which causes vascular injury in DM. We demonstrated that hydrogen peroxide (H2O2) increased Nox4-dependent-ROS aggregation, as well as the expression of TGF-β1, Smad2, Bax and caspase-3, decreased Bcl-2 expression and increased the apoptosis of human umbilical vein endothelial cells (HUVECs). Treatment with diphenyliodonium (DPI), a specific inhibitor of Nox4 or astragaloside IV (AST IV), a monomer located in an extract of astragaloside, decreased Nox4 expression and the levels of ROS, decreased TGF-β1 and Smad2 expression, altered the expression of apoptosis-related genes and decreased the apoptosis of HUVECs. Treatment with LY2109761, a selective inhibitor of the TGF-β1/Smad2 pathway, produced results similar to those of DPI; however, LY2109761 had no effect on Nox4 expression and ROS levels. Taken together, the findings of the present study suggest that H2O2 contributes to HUVEC apoptosis by inducing Nox4-dependent ROS aggregation and activating the TGF-β1/Smad2 signaling pathway. Our data indicate that the protective effects of AST IV against vascular endothelial cell apoptosis in DM are mainly associated with the decrease in Nox4 expression through the TGF-β1/Smad2 signaling pathway. Furthermore, the inhibition of the activation of the TGF-β1/Smad2 signaling pathway may be another potential therapeutic strategy in the treatment of DM.
Collapse
Affiliation(s)
- Yuhong Ma
- Department of Pharmacology, College of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Weizu Li
- Department of Pharmacology, College of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Yanyan Yin
- Department of Pharmacology, College of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Weiping Li
- Department of Pharmacology, College of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| |
Collapse
|
10
|
Davis MI, Simeonov A, Lea W, Auld D. Literature Search and Review. Assay Drug Dev Technol 2014. [DOI: 10.1089/adt.2014.1207.lr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | | | | | - Doug Auld
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| |
Collapse
|