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Liu H, Acharya S, Sudan SK, Hu L, Wu C, Cao Y, Li H, Zhang X. Comparative study of the molecular mechanisms underlying the G protein and β-arrestin-dependent pathways that lead to ERKs activation upon stimulation by dopamine D 2 receptor. FEBS J 2023; 290:5204-5233. [PMID: 37531324 DOI: 10.1111/febs.16921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/09/2023] [Accepted: 08/01/2023] [Indexed: 08/04/2023]
Abstract
Dopamine D2 receptor (D2 R) has been shown to activate extracellular signal-regulated kinases (ERKs) via distinct pathways dependent on either G-protein or β-arrestin. However, there has not been a systematic study of the regulatory process of D2 R-mediated ERKs activation by G protein- versus β-arrestin-dependent signaling since D2 R stimulation of ERKs reflects the simultaneous action of both pathways. Here, we investigated that differential regulation of D2 R-mediated ERKs activation via these two pathways. Our results showed that G protein-dependent ERKs activation was transient, rapid, reached maximum level at around 2 min, and importantly, the activated ERKs were entirely confined to the cytoplasm. In contrast, β-arrestin-dependent ERKs activation was more sustained, slower, reached maximum level at around 10 min, and phosphorylated ERKs translocated into the nucleus. Src was found to be commonly involved in both the G protein- and β-arrestin-dependent pathway-mediated ERKs activation. Pertussis toxin Gi/o inhibitor, GRK2-CT, AG1478 epidermal growth factor receptor inhibitor, and wortmannin phosphoinositide 3-kinase inhibitor all blocked G protein-dependent ERKs activation. In contrast, GRK2 and β-Arr2 played a main role in β-arrestin-dependent ERKs activation. Receptor endocytosis showed minimal effect on the activation of ERKs mediated by both pathways. Furthermore, we found that the formation of a complex composed of phospho-ERKs, β-Arr2, and importinβ1 promoted the nuclear translocation of activated ERKs. The differential regulation of various cellular components, as well as temporal and spatial patterns of ERKs activation via these two pathways, suggest the existence of distinct physiological outcomes.
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Affiliation(s)
- Haiping Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
| | - Srijan Acharya
- Mitchell Cancer Institute, School of Medicine, University of South Alabama, Mobile, AL, USA
| | - Sarabjeet Kour Sudan
- Mitchell Cancer Institute, School of Medicine, University of South Alabama, Mobile, AL, USA
| | - Li Hu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
| | - Chengyan Wu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
| | - Yongkai Cao
- Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, China
| | - Huijun Li
- Department of Pharmaceuticals, People's Hospital of Zunyi City Bo Zhou District, China
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, China
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Rolando M, Barabino S. Are there Clinical Ways to Assess Inflammation in Dry Eye Disease? Ocul Immunol Inflamm 2021; 29:1183-1189. [PMID: 34227903 DOI: 10.1080/09273948.2021.1916540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In the diagnostic process of dry eye disease, the detection of inflammatory activity is critical in order to evaluate the risk of progression and immunologic shift of the disease, to predict patient response to treatment, and to design an efficient therapeutic strategy, including artificial tear replacement, punctal occlusion or anti-inflammatory therapy.Even if it is difficult to quantify, some indicators of the presence of inflammation are collectible during the examination of the ocular surface in a first-line clinical setting. This review presents and critically discusses the assessment of inflammation in dry eye disease in clinical practice.
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Affiliation(s)
- Maurizio Rolando
- Ocular Surface and Dry Eye Clinic, ISPRE Ophthalmica, Genoa, Italy
| | - Stefano Barabino
- Ocular Surface and Dry Eye Center, ASST Fatebenefratelli-Sacco, Sacco Hospital-University of Milan, Milan, Italy
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Fuentes NR, Mlih M, Wang X, Webster G, Cortes-Acosta S, Salinas ML, Corbin IR, Karpac J, Chapkin RS. Membrane therapy using DHA suppresses epidermal growth factor receptor signaling by disrupting nanocluster formation. J Lipid Res 2021; 62:100026. [PMID: 33515553 PMCID: PMC7933808 DOI: 10.1016/j.jlr.2021.100026] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 01/11/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023] Open
Abstract
Epidermal growth factor receptor (EGFR) signaling drives the formation of many types of cancer, including colon cancer. Docosahexaenoic acid (DHA, 22∶6Δ4,7,10,13,16,19), a chemoprotective long-chain n-3 polyunsaturated fatty acid suppresses EGFR signaling. However, the mechanism underlying this phenotype remains unclear. Therefore, we used super-resolution microscopy techniques to investigate the mechanistic link between EGFR function and DHA-induced alterations to plasma membrane nanodomains. Using isogenic in vitro (YAMC and IMCE mouse colonic cell lines) and in vivo (Drosophila, wild type and Fat-1 mice) models, cellular DHA enrichment via therapeutic nanoparticle delivery, endogenous synthesis, or dietary supplementation reduced EGFR-mediated cell proliferation and downstream Ras/ERK signaling. Phospholipid incorporation of DHA reduced membrane rigidity and the size of EGFR nanoclusters. Similarly, pharmacological reduction of plasma membrane phosphatidic acid (PA), phosphatidylinositol-4,5-bisphosphate (PIP2) or cholesterol was associated with a decrease in EGFR nanocluster size. Furthermore, in DHA-treated cells only the addition of cholesterol, unlike PA or PIP2, restored EGFR nanoscale clustering. These findings reveal that DHA reduces EGFR signaling in part by reshaping EGFR proteolipid nanodomains, supporting the feasibility of using membrane therapy, i.e., dietary/drug-related strategies to target plasma membrane organization, to reduce EGFR signaling and cancer risk.
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Affiliation(s)
- Natividad R Fuentes
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Nutrition, Texas A&M University, College Station, TX, USA; Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA
| | - Mohamed Mlih
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Science Center, Bryan, TX, USA
| | - Xiaoli Wang
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Nutrition, Texas A&M University, College Station, TX, USA
| | - Gabriella Webster
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Nutrition, Texas A&M University, College Station, TX, USA
| | - Sergio Cortes-Acosta
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Nutrition, Texas A&M University, College Station, TX, USA
| | - Michael L Salinas
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Nutrition, Texas A&M University, College Station, TX, USA
| | - Ian R Corbin
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jason Karpac
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Science Center, Bryan, TX, USA
| | - Robert S Chapkin
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX, USA; Department of Nutrition, Texas A&M University, College Station, TX, USA; Interdisciplinary Faculty of Toxicology, Texas A&M University, College Station, TX, USA; Center for Translational Environmental Health Research, Texas A&M University, College Station, TX, USA.
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ERK1/2 Signaling Pathway Activated by EGF Promotes Proliferation, Transdifferentiation, and Migration of Cultured Primary Newborn Rat Lung Fibroblasts. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7176169. [PMID: 33083482 PMCID: PMC7559493 DOI: 10.1155/2020/7176169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/25/2020] [Indexed: 12/16/2022]
Abstract
Background Bronchopulmonary dysplasia (BPD) is a common and serious complication in premature infants. Lung fibroblasts (LFs) are present in the extracellular matrix and participate in pulmonary development in response to BPD. The aim of this study was to investigate the effect of extracellular signal-regulated kinase (ERK) on LFs cultured from newborn rats. Material and Methods. Primary LFs were isolated and treated with epidermal growth factor (EGF, 20 ng/mL) in the presence or absence of an ERK inhibitor, PD98059 (10 μmol/L). Phosphorylated ERK1/2 (p-ERK1/2) protein levels were determined using immunocytochemistry, western blotting, and real-time reverse transcription quantitative (RT–q)PCR. LF proliferation was examined by flow cytometry and a cell counting kit-8 assay. LF transdifferentiation was examined by protein and mRNA expression of α-smooth muscle actin (α-SMA) by immunocytochemistry, western blotting, and RT–qPCR. LF migration was examined by the transwell method. Results Phosphorylated ERK1/2, which was activated by EGF, promoted LF proliferation by accelerating cell-cycle progression from the G1 to S phase. After treatment with PD98059, the expression of p-ERK1/2 in LFs, cellular proliferation, and the percentage of cells in S phase were significantly decreased. Phosphorylated ERK1/2 also promoted the differentiation of LFs into myofibroblasts through increased α-SMA synthesis and migration. Conclusion The activation of ERK promotes proliferation, transdifferentiation, and migration of lung fibroblasts from newborn rats.
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Baudouin C, Rolando M, Benitez Del Castillo JM, Messmer EM, Figueiredo FC, Irkec M, Van Setten G, Labetoulle M. Reconsidering the central role of mucins in dry eye and ocular surface diseases. Prog Retin Eye Res 2018; 71:68-87. [PMID: 30471351 DOI: 10.1016/j.preteyeres.2018.11.007] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 11/16/2018] [Accepted: 11/21/2018] [Indexed: 01/16/2023]
Abstract
Mucins are key actors in tear film quality and tear film stability. Alteration of membrane-bound mucin expression on corneal and conjunctival epithelial cells and/or gel-forming mucin secretion by goblet cells (GCs) promotes in ocular surface diseases and dry eye disease (DED). Changes in the mucin layer may lead to enhanced tear evaporation eventually contributing to tear hyperosmolarity which has been associated with ocular surface inflammation. Inflammatory mediators in turn may have a negative impact on GCs differentiation, proliferation, and mucin secretion. This sheds new light on the position of GCs in the vicious circle of DED. As contributor to ocular surface immune homeostasis, GC loss may contribute to impaired ocular surface immune tolerance observed in DED. In spite of this, there are no tools in routine clinical practice for exploring ocular surface mucin deficiency/dysregulation. Therefore, when selecting the most appropriate treatment options, there is a clear unmet need for a better understanding of the importance of mucins and options for their replacement. Here, we comprehensively revisited the current knowledge on ocular surface mucin biology, including functions, synthesis, and secretion as well as the available diagnostic tools and treatment options to improve mucin-associated homeostasis. In particular, we detailed the potential link between mucin dysfunction and inflammation as part of the uncontrolled chronic inflammation which perpetuates the vicious circle in DED.
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Affiliation(s)
- Christophe Baudouin
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, University Versailles Saint Quentin en Yvelines, Paris, France.
| | - Maurizio Rolando
- Ocular Surface & Dry Eye Center, ISPRE Ophthalmics, Genoa, Italy
| | | | | | - Francisco C Figueiredo
- Department of Ophthalmology, Royal Victoria Infirmary and Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | - Murat Irkec
- Department of Ophthalmology, Hacettepe Faculty of Medicine, Ankara, Turkey
| | | | - Marc Labetoulle
- Hôpital Bicêtre, APHP, South Paris University, Ophthalmology, Le Kremlin-Bicêtre, France
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He M, Lippestad M, Li D, Hodges RR, Utheim TP, Dartt DA. Activation of the EGF Receptor by Histamine Receptor Subtypes Stimulates Mucin Secretion in Conjunctival Goblet Cells. Invest Ophthalmol Vis Sci 2018; 59:3543-3553. [PMID: 30025103 PMCID: PMC6049985 DOI: 10.1167/iovs.18-2476] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/18/2018] [Indexed: 01/05/2023] Open
Abstract
Purpose The purpose of this study was to determine if histamine receptors interact with the epidermal growth factor receptor (EGFR) in cultured rat conjunctival goblet cells. Methods Goblet cells from rat conjunctiva were grown in organ culture. First-passage goblet cells were used in all experiments. Phosphorylated (active) and total EGFR, AKT, and extracellular signal-regulated kinase (ERK)1/2 were measured by Western blot analysis. Cells were preincubated with the EGFR antagonist AG1478 for 30 minutes or small interfering RNA specific to the EGFR for 3 days prior to stimulation with histamine or agonists specific for histamine receptor subtypes for 2 hours. Goblet cell secretion was measured using an enzyme-linked lectin assay. Goblet cells were incubated for 1 hour with the calcium indicator molecule fura-2/AM, and intracellular [Ca2+] ([Ca2+]i) was determined. Data were collected in real time and presented as the actual [Ca2+]i with time and as the change in peak [Ca2+]i. Results Histamine increased the phosphorylation of the EGFR. Mucin secretion and increase in [Ca2+]i stimulated by histamine, and agonists specific for each histamine receptor subtype were blocked by inhibition of the EGFR. Increase in [Ca2+]i stimulated by histamine and specific agonists for each histamine receptor was also inhibited by TAPI-1, a matrix metalloproteinase (MMP) inhibitor. The histamine-stimulated increase in activation of AKT, but not ERK1/2, was blocked by AG1478. Conclusions In conjunctival goblet cells, histamine, using all four receptor subtypes, transactivates the EGFR via an MMP. This in turn phosphorylates AKT to increase [Ca2+]i and stimulate mucin secretion.
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Affiliation(s)
- Min He
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
- Department of Ophthalmology, The Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Marit Lippestad
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Dayu Li
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Robin R. Hodges
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
| | - Tor P. Utheim
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
- Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
- Department of Plastic and Reconstructive Surgery, Oslo University Hospital, Oslo, Norway
| | - Darlene A. Dartt
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, United States
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Luettich K, Talikka M, Lowe FJ, Haswell LE, Park J, Gaca MD, Hoeng J. The Adverse Outcome Pathway for Oxidative Stress-Mediated EGFR Activation Leading to Decreased Lung Function. ACTA ACUST UNITED AC 2017. [DOI: 10.1089/aivt.2016.0032] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Karsta Luettich
- Philip Morris International R&D, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Neuchâtel, Switzerland
| | - Marja Talikka
- Philip Morris International R&D, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Neuchâtel, Switzerland
| | - Frazer J. Lowe
- British American Tobacco (Investments) Ltd., Southampton, United Kingdom
| | - Linsey E. Haswell
- British American Tobacco (Investments) Ltd., Southampton, United Kingdom
| | | | - Marianna D. Gaca
- British American Tobacco (Investments) Ltd., Southampton, United Kingdom
| | - Julia Hoeng
- Philip Morris International R&D, Philip Morris Products S.A. (Part of Philip Morris International Group of Companies), Neuchâtel, Switzerland
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Lipoxin A 4 activates ALX/FPR2 receptor to regulate conjunctival goblet cell secretion. Mucosal Immunol 2017; 10:46-57. [PMID: 27072607 PMCID: PMC5063650 DOI: 10.1038/mi.2016.33] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 02/22/2016] [Indexed: 02/04/2023]
Abstract
Conjunctival goblet cells play a major role in maintaining the mucus layer of the tear film under physiological conditions as well as in inflammatory diseases like dry eye and allergic conjunctivitis. Resolution of inflammation is mediated by proresolution agonists such as lipoxin A4 (LXA4) that can also function under physiological conditions. The purpose of this study was to determine the actions of LXA4 on cultured rat conjunctival goblet cell mucin secretion, intracellular [Ca2+] ([Ca2+]i), and identify signaling pathways activated by LXA4. ALX/FPR2 (formyl peptide receptor2) was localized to goblet cells in rat conjunctiva and in cultured goblet cells. LXA4 significantly increased mucin secretion, [Ca2+]i, and extracellular regulated kinase 1/2 (ERK 1/2) activation. These functions were inhibited by ALX/FPR2 inhibitors. Stable analogs of LXA4 increased [Ca2+]i to the same extent as LXA4. Sequential addition of either LXA4 or resolvin D1 followed by the second compound decreased [Ca2+]i of the second compound compared with its initial response. LXA4 activated phospholipases C, D, and A2 and downstream molecules protein kinase C, ERK 1/2, and Ca2+/calmodulin-dependent kinase to increase mucin secretion and [Ca2+]i. We conclude that conjunctival goblet cells respond to LXA4 to maintain the homeostasis of the ocular surface and could be a novel treatment for dry eye diseases.
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Lipoxin A 4 Counter-regulates Histamine-stimulated Glycoconjugate Secretion in Conjunctival Goblet Cells. Sci Rep 2016; 6:36124. [PMID: 27824117 PMCID: PMC5099697 DOI: 10.1038/srep36124] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/11/2016] [Indexed: 12/11/2022] Open
Abstract
Conjunctival goblet cells synthesize and secrete mucins which play an important role in protecting the ocular surface. Pro-resolution mediators, such as lipoxin A4 (LXA4), are produced during inflammation returning the tissue to homeostasis and are also produced in non-inflamed tissues. The purpose of this study was to determine the actions of LXA4 on cultured human conjunctival goblet cell mucin secretion and increase in intracellular [Ca2+] ([Ca2+]i) and on histamine-stimulated responses. LXA4 increased mucin secretion and [Ca2+]i, and activated ERK1/2 in human goblet cells. Addition of LXA4 before resolvin D1 (RvD1) decreased RvD1 responses though RvD1 did not block LXA4 responses. LXA4 inhibited histamine-stimulated increases in mucin secretion, [Ca2+]i, and ERK1/2 activation through activation of β-adrenergic receptor kinase 1. We conclude that conjunctival goblet cells respond to LXA4 through the ALX/FPR2 receptor to maintain homeostasis of the ocular surface and regulate histamine responses and could provide a new therapeutic approach for allergic conjunctivitis and dry eye diseases.
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A Quinone-Containing Compound Enhances Camptothecin-Induced Apoptosis of Lung Cancer Through Modulating Endogenous ROS and ERK Signaling. Arch Immunol Ther Exp (Warsz) 2016; 65:241-252. [PMID: 27677293 DOI: 10.1007/s00005-016-0424-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 07/21/2016] [Indexed: 01/03/2023]
Abstract
The natural compound camptothecin (CPT) derivatives have widely been used for anti-cancer treatments, including lung cancer. However, many chemoresistant cancer cells often develop a relatively higher threshold for inducing apoptosis, causing a limited efficacy of anti-cancer drugs. Likewise, lung cancer cells acquire chemoresistance against CPT analogs, such as irinotecan and topotecan, finally resulting in an unsatisfied outcome and poor prognosis of lung cancer patients. TFPP is a quinone-containing compound as a candidate for CPT-based combination chemotherapy. In this study, we examined the effect of TFPP and CPT cotreatment on non-small cell lung cancer (NSCLC) cells. Cell proliferation and flow cytometry-based Annexin-V/PI staining assays demonstrated the synergistic effect of TFPP on CPT-induced apoptosis in both NSCLC A549 and H1299 cells. The results of CPT and TFPP cotreatment cause the regulation of the ERK-Bim axis and the activation of mitochondrial-mediated caspase cascade, including caspase-9 and caspase-3. Besides, TFPP significantly enhanced CPT-induced endogenous reactive oxygen species (ROS) in the two NSCLC cells. In contrast, the treatment of N-acetyl-L-cysteine (NAC), an ROS scavenger, rescues the apoptosis of NSCLC cells induced by TFPP and CPT cotreatment, suggesting that the synergistic effect of TFPP on CPT-induced anti-NSCLC cells is through upregulating ROS production. Consequently, our results suggest that TFPP sensitizes NSCLC towards CPT-based chemotherapy may act through decreasing the apoptosis-initiating threshold. Therefore, TFPP may be a promising chemosensitizer for lung cancer treatment, and the underlying mechanism warrants further.
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Conjunctival epithelial and goblet cell function in chronic inflammation and ocular allergic inflammation. Curr Opin Allergy Clin Immunol 2015; 14:464-70. [PMID: 25061855 DOI: 10.1097/aci.0000000000000098] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW Although conjunctival goblet cells are a major cell type in ocular mucosa, their responses during ocular allergy are largely unexplored. This review summarizes the recent findings that provide key insights into the mechanisms by which their function and survival are altered during chronic inflammatory responses, including ocular allergy. RECENT FINDINGS Conjunctiva represents a major component of the ocular mucosa that harbors specialized lymphoid tissue. Exposure of mucin-secreting goblet cells to allergic and inflammatory mediators released by the local innate and adaptive immune cells modulates proliferation, secretory function, and cell survival. Allergic mediators like histamine, leukotrienes, and prostaglandins directly stimulate goblet cell mucin secretion and consistently increase goblet cell proliferation. Goblet cell mucin secretion is also detectable in a murine model of allergic conjunctivitis. Additionally, primary goblet cell cultures allow evaluation of various inflammatory cytokines with respect to changes in goblet cell mucin secretion, proliferation, and apoptosis. These findings in combination with the preclinical mouse models help understand the goblet cell responses and their modulation during chronic inflammatory diseases, including ocular allergy. SUMMARY Recent findings related to conjunctival goblet cells provide the basis for novel therapeutic approaches, involving modulation of goblet cell mucin production, to improve treatment of ocular allergies.
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Yang L, Yan Y. Protein kinases are potential targets to treat inflammatory bowel disease. World J Gastrointest Pharmacol Ther 2014; 5:209-217. [PMID: 25374761 PMCID: PMC4218950 DOI: 10.4292/wjgpt.v5.i4.209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 04/05/2014] [Accepted: 07/29/2014] [Indexed: 02/06/2023] Open
Abstract
Protein kinases play a crucial role in the pathogenesis of inflammatory bowel disease (IBD), the two main forms of which are ulcerative colitis and Crohn’s disease. In this article, we will review the mechanisms of involvement of protein kinases in the pathogenesis of and intervention against IBD, in terms of their effects on genetics, microbiota, mucous layer and tight junction, and the potential of protein kinases as therapeutic targets against IBD.
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Li D, Shatos MA, Hodges RR, Dartt DA. Role of PKCα activation of Src, PI-3K/AKT, and ERK in EGF-stimulated proliferation of rat and human conjunctival goblet cells. Invest Ophthalmol Vis Sci 2013; 54:5661-74. [PMID: 23882690 DOI: 10.1167/iovs.13-12473] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To determine the order and components of the signaling pathway utilized by epidermal growth factor (EGF) to stimulate conjunctival goblet cell proliferation. METHODS Goblet cells from rat bulbar and forniceal conjunctiva and human bulbar conjunctiva were grown in organ culture. Goblet cells (GCs) were serum starved for 24 hours and preincubated with inhibitors for 30 minutes or small interfering RNA (siRNA) for 48 hours prior to addition of EGF. Proliferation was then measured or Western blot analysis was performed using antibodies against phosphorylated protein kinase B (AKT), extracellular signal-regulated kinase 1/2 (ERK1/2), or the non-receptor tyrosine kinase Src. Rat GCs were also incubated with adenoviruses expressing dominant negative protein kinase Cα (DNPKCα) or constitutively activated protein kinase Cα (myrPKCα), and activation of AKT and ERK1/2 was determined by Western blot analysis. RESULTS Inhibitors of phosphoinositol-3 kinase (PI-3K)/AKT pathway blocked EGF-stimulated ERK1/2 activation and GC proliferation. Inhibitors of EGF-stimulated ERK1/2 activity did not inhibit AKT activation but blocked proliferation. DNPKCα blocked EGF-stimulated activation of AKT and ERK1/2 while myrPKCα increased activation of these kinases. Inhibitors of PI-3K, ERK1/2, and protein kinase C (PKC) blocked myrPKCα-stimulated GC proliferation. EGF and myrPKCα increased phosphorylation of Src, and inhibition of Src with the chemical inhibitor PP1 or siRNA inhibited EGF-stimulated GC proliferation. CONCLUSIONS We found that EGF activates a major pathway to stimulate goblet cell proliferation. This pathway consists of induction of phospholipase C (PLC)γ to activate PKCα. Active PKCα phosphorylates Src to induce PI-3K to phosphorylate AKT that subsequently activates the ERK1/2 cascade to stimulate goblet cell proliferation.
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Affiliation(s)
- Dayu Li
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
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Hodges RR, Dartt DA. Tear film mucins: front line defenders of the ocular surface; comparison with airway and gastrointestinal tract mucins. Exp Eye Res 2013; 117:62-78. [PMID: 23954166 DOI: 10.1016/j.exer.2013.07.027] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/07/2013] [Accepted: 07/24/2013] [Indexed: 01/09/2023]
Abstract
The ocular surface including the cornea and conjunctiva and its overlying tear film are the first tissues of the eye to interact with the external environment. The tear film is complex containing multiple layers secreted by different glands and tissues. Each layer contains specific molecules and proteins that not only maintain the health of the cells on the ocular surface by providing nourishment and removal of waste products but also protect these cells from environment. A major protective mechanism that the corneal and conjunctival cells have developed is secretion of the innermost layer of the tear film, the mucous layer. Both the cornea and conjunctiva express membrane spanning mucins, whereas the conjunctiva also produces soluble mucins. The mucins present in the tear film serve to maintain the hydration of the ocular surface and to provide lubrication and anti-adhesive properties between the cells of the ocular surface and conjunctiva during the blink. A third function is to contribute to the epithelial barrier to prevent pathogens from binding to the ocular surface. This review will focus on the different types of mucins produced by the corneal and conjunctival epithelia. Also included in this review will be a presentation of the structure of mucins, regulation of mucin production, role of mucins in ocular surface diseases, and the differences in mucin production by the ocular surface, airways and gastrointestinal tract.
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Affiliation(s)
- Robin R Hodges
- Schepens Eye Research Institute/Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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Tsai HF, Huang CW, Chang HF, Chen JJW, Lee CH, Cheng JY. Evaluation of EGFR and RTK signaling in the electrotaxis of lung adenocarcinoma cells under direct-current electric field stimulation. PLoS One 2013; 8:e73418. [PMID: 23951353 PMCID: PMC3739739 DOI: 10.1371/journal.pone.0073418] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022] Open
Abstract
Physiological electric field (EF) plays a pivotal role in tissue development and regeneration. In vitro, cells under direct-current electric field (dcEF) stimulation may demonstrate directional migration (electrotaxis) and long axis reorientation (electro-alignment). Although the biophysical models and biochemical signaling pathways behind cell electrotaxis have been investigated in numerous normal cells and cancer cells, the molecular signaling mechanisms in CL1 lung adenocarcinoma cells have not been identified. Two subclones of CL1 cells, the low invasive CL1-0 cells and the highly invasive CL 1-5 cells, were investigated in the present study. CL1-0 cells are non-electrotactic while the CL 1-5 cells are anodally electrotactic and have high expression level of epidermal growth factor receptor (EGFR), in this study, we investigated the generally accepted hypothesis of receptor tyrosine kinase (RTK) activation in the two cell lines under dcEF stimulation. Erbitux, a therapeutic drug containing an anti-EGFR monoclonal antibody, cetuximab, was used to investigate the EGFR signaling in the electrotaxis of CL 1-5 cells. To investigate RTK phosphorylation and intracellular signaling in the CL1 cells, large amount of cellular proteins were collected in an airtight dcEF stimulation device, which has advantages of large culture area, uniform EF distribution, easy operation, easy cell collection, no contamination, and no medium evaporation. Commercial antibody arrays and Western blotting were used to study the phosphorylation profiles of major proteins in CL1 cells under dcEF stimulation. We found that electrotaxis of CL 1-5 cells is serum independent and EGFR independent. Moreover, the phosphorylation of Akt and S6 ribosomal protein (rpS6) in dcEF-stimulated CL1 cells are different from that in EGF-stimulated cells. This result suggests that CL1 cells' response to dcEF stimulation is not through EGFR-triggered pathways. The new large-scale dcEF stimulation device developed in the present work will aid the sample preparation for protein-based experiments.
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Affiliation(s)
- Hsieh-Fu Tsai
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
- Biophotonics & Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Ching-Wen Huang
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Hui-Fang Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
| | - Jeremy J. W. Chen
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Chau-Hwang Lee
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
- Biophotonics & Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Ji-Yen Cheng
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
- Biophotonics & Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan
- Department of Mechanical and Mechatronic Engineering, National Taiwan Ocean University, Keelung, Taiwan
- * E-mail:
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Osmoprotective effects of supplemental epidermal growth factor in an ex vivo multilayered human conjunctival model under hyperosmotic stress. Graefes Arch Clin Exp Ophthalmol 2013; 251:1945-53. [PMID: 23677487 DOI: 10.1007/s00417-013-2369-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 04/03/2013] [Accepted: 04/25/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND To analyze the effects of supplemental epidermal growth factor (EGF) and the roles of inflammatory cytokines (interleukin [IL]-6) in an ex vivo dry-eye model under hyperosmotic stress using a multilayered culture of human conjunctival epithelial cells (HCECs). METHODS Multilayered cultures of HCECs were exposed to hyperosmotic stress (400 mOsm/L) for 24 h in addition to 0.5 ng/mL EGF (low-EGF group) or 25 ng/mL EGF (high-EGF group). Apoptosis was analyzed using the TUNEL assay. Cell proliferation was measured using the [3H]-thymidine incorporation assay. The expression of IL-6, EGF, EGF receptor (EGFR), and phosphorylated extracellular signal-regulated kinase (p-ERK) was measured by western blot analysis. The secretion of IL-6 was measured using ELISA. Western blot analysis was also performed using antibodies against cleaved caspase-3. RESULTS The percentage of apoptotic cells was lower in the high-EGF group (6.7%) than in the low-EGF group (10.3%). The high-EGF group demonstrated increased proliferation (323.7 counts/min in the low-EGF group vs 649.1 counts/min in the high-EGF group). EGF induced higher phosphor-EGFR expression and upregulated p-ERK in HCECs. In addition, EGF significantly decreased the secretion of IL-6 and cleaved caspase-3 in HCECs. CONCLUSIONS The level of IL-6 was increased in the ex vivo HCEC dry-eye model that was under hyperosmotic stress. Supplemental EGF reduces the level of IL-6, decreases apoptosis, and increases proliferation. These findings indicate that EGF has potential as a therapeutic agent for the treatment of dry eyes.
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Fostad IG, Eidet JR, Shatos MA, Utheim TP, Utheim OA, Raeder S, Dartt DA. Biopsy harvesting site and distance from the explant affect conjunctival epithelial phenotype ex vivo. Exp Eye Res 2012; 104:15-25. [PMID: 23022405 DOI: 10.1016/j.exer.2012.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2012] [Revised: 08/28/2012] [Accepted: 09/17/2012] [Indexed: 12/11/2022]
Abstract
The purpose of the study was to investigate if the number of goblet cells expanded ex vivo from a conjunctival explant is affected by the biopsy harvesting site on the conjunctiva and the distance from the explant. Conjunctival explants from six regions: superior and inferior bulbus, fornix, and tarsus of male Sprague-Dawley rats were grown in RPMI 1640 with 10% fetal bovine serum on coverslips for eight days. Histochemical and immunofluorescent staining of goblet (CK-7/UEA-1/MUC5AC), stratified squamous, non-goblet (CK-4), proliferating (PCNA) and progenitor (ABCG2) cells were analyzed by epifluorescence and laser confocal microscopy. Outgrowth was measured with NIH ImageJ. For statistical analysis the Mann-Whitney test and Spearman's rank-order correlation test were used. Cultures from superior and inferior fornix contained the most goblet cells as indicated by the presence of CK-7+, UEA-1+ and MUC5AC+ cells. Superior and inferior forniceal cultures displayed 60.8% ± 9.2% and 64.7% ± 6.7% CK-7+ cells, respectively, compared to the superior tarsal (26.6% ± 8.4%; P < 0.05), superior bulbar (31.0% ± 4.0%; P < 0.05), inferior bulbar (38.5% ± 9.3%; P < 0.05) and inferior tarsal cultures (27.7% ± 8.3%; P < 0.05). While 28.4% ± 6.3% of CK-7+ goblet cells co-labeled with PCNA, only 7.4% ± 1.6% of UEA-1+ goblet cells did (P < 0.01). CK-7+ goblet cells were located at a lower concentration close to the explant (39.8% ± 3.1%) compared to near the leading edge (58.2% ± 4.5%; P < 0.05). Both markers for goblet cell secretory product (UEA-1 and MUC5AC), however, displayed the opposite pattern with a higher percentage of positive cells close to the explant than near the leading edge (P < 0.05). The percentage of CK-4+ cells was higher near the explant compared to near the leading edge (P < 0.01). The percentage of CK-7+ goblet cells in the cultures did not correlate with the outgrowth size (r(s) = -0.086; P = 0.435). The percentage of UEA-1+ goblet cells correlated negatively with outgrowth size (r(s) = -0.347; P < 0.01), whereas the percentage of CK-4+ cells correlated positively with the outgrowth size (r(s) = 0.473; P < 0.05). We conclude that forniceal explants yield the highest number of goblet cells ex vivo and thereby seem to be optimal for goblet cell transplantation. We also suggest that CK-7+/UEA-1- cells represent highly proliferative immature goblet cells. These cells could be important during conjunctival migration as they are mostly located close to the leading edge and their density does not decrease with increasing outgrowth size.
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Affiliation(s)
- I G Fostad
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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18
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Hodges RR, Bair JA, Carozza RB, Li D, Shatos MA, Dartt DA. Signaling pathways used by EGF to stimulate conjunctival goblet cell secretion. Exp Eye Res 2012; 103:99-113. [PMID: 22975404 DOI: 10.1016/j.exer.2012.08.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 07/19/2012] [Accepted: 08/26/2012] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to identify the signaling pathways that epidermal growth factor (EGF) uses to stimulate mucin secretion from cultured rat conjunctival goblet cells and to compare the pathways used by EGF with those used by the known secretagogue muscarinic, cholinergic agonists. To this end, goblet cells from rat conjunctiva were grown in culture using RPMI media. For immunofluorescence experiments, antibodies against EGF receptor (EGFR) and ERK 2 as well as muscarinic receptors (M(1)AchR, M(2)AchR, and M(3)AchR) were used, and the cells viewed by fluorescence microscopy. Intracellular [Ca(2+)] ([Ca(2+)](i)) was measured using fura 2/AM. Glycoconjugate secretion was determined after cultured goblet cells were preincubated with inhibitors, and then stimulated with EGF or the cholinergic agonist carbachol (Cch). Goblet cell secretion was measured using an enzyme-linked lectin assay with UEA-I or ELISA for MUC5AC. In cultured goblet cells EGF stimulated an increase in [Ca(2+)](i) in a concentration-dependent manner. EGF-stimulated increase in [Ca(2+)](i) was blocked by inhibitors of the EGF receptor and removal of extracellular Ca(2+). Inhibitors against the EGFR and ERK 1/2 blocked EGF-stimulated mucin secretion. In addition, cultured goblet cells expressed M(1)AchR, M(2)AchR, and M(3)AchRs. Cch-stimulated increase in [Ca(2+)](i) was blocked by inhibitors for the M(1)AchRs, matrix metalloproteinases, and EGF receptors. Inhibitors against the EGF receptor and ERK 1/2 also blocked Cch-stimulated mucin secretion. We conclude that in conjunctival goblet cells, EGF itself increases [Ca(2+)](i) and activates ERK 1/2 to stimulate mucin secretion. EGF-stimulated secretion is dependent on extracellular Ca(2+). This mechanism of action is similar to cholinergic agonists that use muscarinic receptors to transactivate the EGF receptor, increase [Ca(2+)](i), and activate ERK 1/2 leading to an increase in mucin secretion.
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Affiliation(s)
- Robin R Hodges
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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Dartt DA, Hodges RR, Li D, Shatos MA, Lashkari K, Serhan CN. Conjunctival goblet cell secretion stimulated by leukotrienes is reduced by resolvins D1 and E1 to promote resolution of inflammation. THE JOURNAL OF IMMUNOLOGY 2011; 186:4455-66. [PMID: 21357260 DOI: 10.4049/jimmunol.1000833] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The conjunctiva is a mucous membrane that covers the sclera and lines the inside of the eyelids. Throughout the conjunctiva are goblet cells that secrete mucins to protect the eye. Chronic inflammatory diseases such as allergic conjunctivitis and early dry eye lead to increased goblet cell mucin secretion into tears and ocular surface disease. The purpose of this study was to determine the actions of the inflammatory mediators, the leukotrienes and the proresolution resolvins, on secretion from cultured rat and human conjunctival goblet cells. We found that both cysteinyl leukotriene (CysLT) receptors, CysLT(1) and CysLT(2,) were present in rat conjunctiva and in rat and human cultured conjunctival goblet cells. All leukotrienes LTB(4), LTC(4), LTD(4), and LTE(4), as well as PGD(2), stimulated goblet cell secretion in rat goblet cells. LTD(4) and LTE(4) increased the intracellular Ca(2+) concentration ([Ca(2+)](i)), and LTD(4) activated ERK1/2. The CysLT(1) receptor antagonist MK571 significantly decreased LTD(4)-stimulated rat goblet cell secretion and the increase in [Ca(2+)](i). Resolvins D1 (RvD1) and E1 (RvE1) completely reduced LTD(4)-stimulated goblet cell secretion in cultured rat goblet cells. LTD(4)-induced secretion from human goblet cells was blocked by RvD1. RvD1 and RvE1 prevented LTD(4)- and LTE(4)-stimulated increases in [Ca(2+)](i), as well as LTD(4) activation of ERK1/2. We conclude that cysteinyl leukotrienes stimulate conjunctival goblet cell mucous secretion with LTD(4) using the CysLT(1) receptor. Stimulated secretion is terminated by preventing the increase in [Ca(2+)](i) and activation of ERK1/2 by RvD1 and RvE1.
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Affiliation(s)
- Darlene A Dartt
- Schepens Eye Research Institute, Harvard Medical School, Boston, MA 02114, USA.
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Liang C, Ren Y, Tan H, He Z, Jiang Q, Wu J, Zhen Y, Fan M, Wu Z. Rosiglitazone via upregulation of Akt/eNOS pathways attenuates dysfunction of endothelial progenitor cells, induced by advanced glycation end products. Br J Pharmacol 2010; 158:1865-73. [PMID: 19917066 DOI: 10.1111/j.1476-5381.2009.00450.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE Advanced glycation end products (AGEs) and endothelial progenitor cells (EPCs) play key roles in pathogenesis of diabetes-related vascular complications. AGEs can induce dysfunction in EPCs. The peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists are widely used in the treatment of type 2 diabetes, and it remains unknown if they could attenuate EPC dysfunction induced by AGEs. EXPERIMENTAL APPROACH EPCs isolated from healthy adults were cultured with various concentrations of AGEs (0, 50, 100 and 200 mg L(-1)) with or without rosiglitazone (10 nM), antibody for the receptors for AGE-human serum albumin (anti-receptor for advanced glycation end products (RAGE); 50 microg mL(-1)), phosphatidylinositol-3-kinase (PI3K) inhibitor (LY294002, 5 microM), nitric oxide (NO) synthase inhibitor (L-N(G)-nitro-arginine methyl ester (L-NAME), 100 microM) or sodium nitroprusside (SNP, 25 microM). Proliferation, apoptosis, cell adhesion, migration and NO production in EPCs were assessed, and expressions of endothelial NO synthase (eNOS) and Akt were determined. KEY RESULTS Number, proliferation/migration capacities, eNOS and Akt phosphorylation as well as NO synthesized by EPCs were increased by rosiglitazone and reduced by AGEs. AGEs promoted while rosiglitazone reduced EPC apoptosis. The AGE-induced effects were significantly ameliorated by pre-incubation with rosiglitazone, RAGE antibody and SNP. The beneficial effects of rosiglitazone could be blocked by pretreatment with L-NAME and LY294002. CONCLUSIONS AND IMPLICATIONS The PPARgamma agonist rosiglitazone increased EPC function and attenuated EPC dysfunction induced by AGEs via upregulating the Akt-eNOS signal pathways of EPCs.
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Affiliation(s)
- Chun Liang
- Department of Cardiology, Second Hospital Affiliated to the Second Military Medical University, Shanghai, China
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Qiang H, Xu HJ, Zhou GX, Huang JF, Huang H, Zhang H. Expression of extracellular signal-regulated kinase in hepatic fibrosis and its correlation with collagen type I and III. Shijie Huaren Xiaohua Zazhi 2009; 17:770-774. [DOI: 10.11569/wcjd.v17.i8.770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the expression of ERK during the development of hepatic fibrosis and the correlation of ERK and I, III collagens.
METHODS: Hepatic fibrosis was induced by subcutaneous injection of DMN. Rats were killed for study at the end of first, second, third weeks and the clinical operative liver samples were collected. The development expression and location of the ERK in the hepatic tissue and the correlation of ERK with collagen I, III were assessed by means of immunohistochemistry.
RESULTS: The expression of ERK was increased and was closely correlated with that of collagen I and III during the development of rat fibrosis at every time point (1 wk: r = 0.75, 0.68, P < 0.05; 2 wk: r = 0.82, 0.78, P < 0.05; 3 wk: r = 0.74, 0.83, P < 0.05). Similarly, the expression of ERK was enhanced in human fibrotic tissues (1.068 ± 0.258 vs 0.035 ± 0.011, P < 0.05), which was correlated with that of collagen I and III (r = 0.87, 0.88, all P < 0.05).
CONCLUSION: The ERK signal pathway may play an important role in the pathogenesis of hepatic fibrosis.
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Shatos MA, Hodges RR, Bair JA, Lashkari K, Dartt DA. Stimulatory role of PKCalpha in extracellular regulated kinase 1/2 pathway in conjunctival goblet cell proliferation. Invest Ophthalmol Vis Sci 2008; 50:1619-25. [PMID: 19074803 DOI: 10.1167/iovs.08-2930] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To determine whether a constitutively active protein kinase C (PKC)-alpha stimulates rat and human conjunctival goblet cell proliferation through activation of ERK 1/2. METHODS Conjunctivas from rat and human were minced and goblet cells were allowed to grow. Goblet cells were serum starved and incubated with an adenovirus containing a constitutively active form of PKCalpha (Ad-myr-PKCalpha, 1 x 10(7) pfu), EGF (10(-7) M), or both. The location of myrPKCalpha was determined by immunofluorescence microscopy. Cultured goblet cells were preincubated with the PKC inhibitor calphostin C (10(-10)-10(-7) M) or the ERK 1/2 inhibitor U0126 (10(-9)-10(-6) M) before incubation with Ad-myr-PKCalpha. Cell proliferation was measured. RESULTS Transduction of rat goblet cells with Ad-myr-PKCalpha did not change PKC location compared with nontransduced cells. Incubation with Ad-myr-PKCalpha caused an increase in cell proliferation by 2.5+/-0.3-fold, whereas EGF increased proliferation by 2.1+/-0.2-fold. Simultaneous addition of Ad-myr-PKCalpha and EGF did not further increase proliferation. U0126 inhibited Ad-myr-PKCalpha-stimulated proliferation a maximum of 70%. In human goblet cells, incubation with Ad-myr-PKCalpha caused an increase in cell proliferation by 2.3+/-0.3-fold, whereas EGF increased proliferation by 3.1+/-0.4-fold. Simultaneous addition of Ad-myr-PKCalpha and EGF decreased proliferation compared with either compound alone. Ad-myr-PKCalpha caused ERK 1/2 to translocate to the nucleus in rat and human cells, but the translocation was blocked by U0126. CONCLUSIONS Activation of PKCalpha alone by inducing phosphorylation of ERK 1/2 and translocating it to the nucleus is necessary and sufficient to cause conjunctival cell proliferation in rat, and probably human, goblet cells.
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Affiliation(s)
- Marie A Shatos
- Schepens Eye Research Institute, Boston, Massachusetts 02114, USA
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Shatos MA, Hodges RR, Oshi Y, Bair JA, Zoukhri D, Kublin C, Lashkari K, Dartt DA. Role of cPKCalpha and nPKCepsilon in EGF-stimulated goblet cell proliferation. Invest Ophthalmol Vis Sci 2008; 50:614-20. [PMID: 18824739 DOI: 10.1167/iovs.08-2467] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The authors determined the role of the protein kinase C (PKC) isoforms cPKCalpha and nPKCepsilon in EGF-stimulated proliferation of cultured rat and human conjunctival goblet cells. METHODS Rat and human conjunctivas were minced, and goblet cells were allowed to grow. Passage 1 cells were serum starved for 24 to 48 hours and were incubated with the PKC inhibitors calphostin C and Gö 6983 (10(-10)-10(-7) M) for 20 minutes before stimulation with EGF (10(-7) M) for 24 hours. The presence and localization of PKC isoforms in cultured rat goblet cells were determined by Western blot analysis and immunofluorescence microscopy, respectively. Cultured rat goblet cells were serum starved and incubated with adenoviruses containing genes for dominant-negative cPKCalpha (Ad DNPKCalpha, 10(4) pfu), dominant-negative nPKCepsilon (Ad DNPKCepsilon, 10(4) pfu), and wild-type cPKCalpha (Ad WTPKCalpha, 10(7) pfu), and proliferation was measured. RESULTS In rat goblet cells, EGF-stimulated proliferation was completely inhibited by calphostin C, whereas Gö 6983 inhibited proliferation by 53%+/-15%. In human goblet cells, EGF-stimulated proliferation was completely inhibited by calphostin C. PKCalpha, -betaI, -betaII, -delta, -epsilon, -iota/lambda, -theta, -gamma, and -zeta were found in cultured rat goblet cells. Ad DNPKCalpha and Ad DNPKCepsilon inhibited EGF-stimulated proliferation in rat goblet cells by 78%+/-6% and 92%+/-8%, respectively. Incubation with Ad WTPKCalpha alone significantly increased proliferation. CONCLUSIONS cPKCalpha and nPKCepsilon play key roles in conjunctival goblet cell proliferation.
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Affiliation(s)
- Marie A Shatos
- Schepens Eye Research Institute and Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA
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