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Schloesser L, Klose SM, Mauschitz MM, Abdullah Z, Finger RP. The role of immune modulators in age-related macular degeneration. Surv Ophthalmol 2024:S0039-6257(24)00084-5. [PMID: 39097172 DOI: 10.1016/j.survophthal.2024.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 07/27/2024] [Accepted: 07/29/2024] [Indexed: 08/05/2024]
Abstract
We provide an overview of the expanding literature on the role of cytokines and immune mediators in pathophysiology of age-related macular degeneration (AMD). Although many immunological mediators have been linked to AMD pathophysiology, the broader mechanistic picture remains unclear with substantial variations in the levels of evidence supporting these mediators. Therefore, we reviewed the literature considering the varying levels of supporting evidence. A Medical Subject Headings (MeSH) term-based literature research was conducted in September, 2023, consisting of the MeSH terms "cytokine" and "Age-related macular degeneration" connected by the operator "AND". After screening the publications by title, abstract, and full text, a total of 146 publications were included. The proinflammatory cytokines IL-1β (especially in basic research studies), IL-6, IL-8, IL-18, TNF-α, and MCP-1 are the most extensively characterised cytokines/chemokines, highlighting the role of local inflammasome activation and altered macrophage function in the AMD pathophysiology. Among the antiinflammatory mediators IL-4, IL-10, and TGF-β were found to be the most extensively characterised, with IL-4 driving and IL-10 and TGF-β suppressing disease progression. Despite the extensive literature on this topic, a profound understanding of AMD pathophysiology has not yet been achieved. Therefore, further studies are needed to identify potential therapeutic targets, followed by clinical studies.
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Affiliation(s)
- Lukas Schloesser
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Sara M Klose
- Institute of Molecular Medicine and Experimental Immunology, University of Bonn, Bonn, Germany; Asia-Pacific Centre for Animal Health, Faculty of Science, University of Melbourne, Melbourne, Australia
| | | | - Zeinab Abdullah
- Institute of Molecular Medicine and Experimental Immunology, University of Bonn, Bonn, Germany
| | - Robert P Finger
- Department of Ophthalmology, University of Bonn, Bonn, Germany; Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Kaur B, Miglioranza Scavuzzi B, F Abcouwer S, N Zacks D. A simplified protocol to induce hypoxia in a standard incubator: A focus on retinal cells. Exp Eye Res 2023; 236:109653. [PMID: 37793495 PMCID: PMC10732591 DOI: 10.1016/j.exer.2023.109653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/11/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023]
Abstract
Hypoxia chambers have traditionally been used to induce hypoxia in cell cultures. Cellular responses to hypoxia can also be mimicked with the use of chemicals such as cobalt chloride (CoCl2), which stabilizes hypoxia-inducible factor alpha-subunit proteins. In studies of ocular cells using primary cells and cell lines, such as Müller glial cell (MGC) lines, photoreceptor cell lines, retinal pigment epithelial (RPE) cell lines and retinoblastoma cell lines oxygen levels employed in hypoxia chambers range typically between 0.2% and 5% oxygen. For chemical induction of hypoxic response in these cells, the CoCl2 concentrations used typically range from 100 to 600 μM. Here, we describe simplified protocols for stabilizing cellular hypoxia-inducible factor-1α (HIF-1α) in cell culture using either a hypoxia chamber or CoCl2. In addition, we also provide a detailed methodology to confirm hypoxia induction by the assessment of protein levels of HIF-1α, which accumulates in response to hypoxic conditions. Furthermore, we provide a summary of conditions applied in previous studies of ocular cells.
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Affiliation(s)
- Bhavneet Kaur
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Bruna Miglioranza Scavuzzi
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Steven F Abcouwer
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - David N Zacks
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, MI, USA.
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Venkatesh R, Parmar Y, Chitturi SP, Mangla R, Yadav NK, Chhablani J. Ocular blood vessel arrangement in choroidal coloboma. Eye (Lond) 2023; 37:2781-2787. [PMID: 36717708 PMCID: PMC10482966 DOI: 10.1038/s41433-023-02420-3] [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: 09/10/2022] [Revised: 12/12/2022] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE To describe the ocular blood vessel arrangement in choroidal coloboma eyes. METHODS In this retrospective, observational cross-sectional study, fundus images from 69 coloboma eyes of 45 patients were classified as per Ida Mann's classification. The arrangement and distribution of retinal, choroidal, and episcleral vessels, as well as vortex veins, were observed in non-colobomatous, colobomatous, and extra-colobomatous regions. RESULTS Seventy-eight colobomas were identified. There were 12 type 1, 13 type 2, 10 type 3, 13 type 4, 11 type 5, 4 type 6 and 15 type 7 colobomas respectively. In most cases of type 1 and 2 colobomas, origin of retinal blood vessels could not be determined. In colobomas type 3-7, retinal blood vessels originated either from the optic disc centre or, rarely, from the optic disc or coloboma margin. Eyes with large and deep type 1, 2, 3 and 7 colobomas showed prominent choroidal vessels in the non-colobomatous region and around the coloboma. Small choroidal colobomas lacked prominent choroidal vessels. Similarly, prominent extraocular episcleral vessels within the coloboma bed were observed in eyes with colobomas of types 1, 2, 3 and 7. Vortex veins were visible in 70% of coloboma eyes. They were more commonly seen with small focal colobomas and less frequently with large deep colobomas. CONCLUSION Coloboma eyes have variations in the arrangement and distribution of ocular blood vessels. The position, size, and antero-posterior extent of the choroidal coloboma are the primary determinants of how these blood vessels are arranged. Future research would benefit from additional imaging with indocyanine green angiography.
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Affiliation(s)
- Ramesh Venkatesh
- Department of Retina and Vitreous, Narayana Nethralaya, #121/C, 1st R block, Chord Road, Rajaji Nagar, Bangalore, 560010, India.
| | - Yash Parmar
- Department of Retina and Vitreous, Narayana Nethralaya, #121/C, 1st R block, Chord Road, Rajaji Nagar, Bangalore, 560010, India
| | - Sai Prashanti Chitturi
- Department of Retina and Vitreous, Narayana Nethralaya, #121/C, 1st R block, Chord Road, Rajaji Nagar, Bangalore, 560010, India
| | - Rubble Mangla
- Department of Retina and Vitreous, Narayana Nethralaya, #121/C, 1st R block, Chord Road, Rajaji Nagar, Bangalore, 560010, India
| | - Naresh Kumar Yadav
- Department of Retina and Vitreous, Narayana Nethralaya, #121/C, 1st R block, Chord Road, Rajaji Nagar, Bangalore, 560010, India
| | - Jay Chhablani
- University of Pittsburgh School of Medicine, Medical Retina and Vitreoretinal Surgery, 203 Lothrop Street, Suite 800, Pittsburg, PA, 15213, USA
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Lin Y, Peng T, Li Y, Liu Y. The frequency of early age-related macular degeneration and its relationship with dietary pattern in Hunan, China: a cross-sectional study. BMC Ophthalmol 2022; 22:324. [PMID: 35896997 PMCID: PMC9327240 DOI: 10.1186/s12886-022-02549-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/22/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To estimate the frequency of age-related macular degeneration (AMD) among people who underwent health examination in Hunan, China and to determine the relationship between dietary pattern and the risk of AMD. METHODS The Questionnaire was used to collect dietary data from 56,775 study participants of ≥ 50 years old who underwent health examination at the Department of Health Management, the Third Xiangya Hospital of Central South University between January 2017 and December 2019. The diagnosis of AMD was based on the results of color fundus photography (CFP), spectral-domain optical coherence tomography (OCT) and multispectral imaging (MSI). After excluding participants with incomplete records or other ocular disease that may affect the results of fundus examination, a total of 43,672 study participants were included. The univariate and multivariate logistic regression analyses were used to determine the relationship between dietary pattern and the frequency of AMD. RESULTS Among the 43,672 study participants, 1080 (2.5%) had early AMD: the frequencies were 2.6% (n = 674) in men and 2.3% (n = 406) in women; the frequencies were 1.0% (n = 289), 3.6% (n = 401), 9.1% (n = 390) in 50-59, 60-69, ≥ 70 years old, respectively. And the age-standard frequency was 6.6% over the 60 years old in Hunan China. The high-salt intake increased the risk of early AMD [odds ratio (OR) = 1.61, 95% confidence interval (CI) = 1.54-1.68], whereas the intake of meat decreased the risk (OR = 0.90, 95% CI = 0.81-0.99). CONCLUSION In Hunan China, there was a high frequency of early AMD detected through health examination over the 60 years old. And high-salt intake increases the risk of early AMD, whereas intake of meat decreases the risk. Modulating the dietary pattern and reducing the salt intake as an AMD prevention strategy warrant further study.
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Affiliation(s)
- Yanhui Lin
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ting Peng
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ying Li
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yu Liu
- Department of Ophthalmology, The Third Xiangya Hospital, Central South University, Street address: No.138,Tongzipo Road,Yuelu District, Hunan, 410013, Changsha, China.
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Beer MC, Kuhrt H, Kohen L, Wiedemann P, Bringmann A, Hollborn M. Kir4.2 Potassium Channels in Retinal Pigment Epithelial Cells In Vitro: Contribution to Cell Viability and Proliferation, and Down-Regulation by Vascular Endothelial Growth Factor. Biomolecules 2022; 12:biom12060848. [PMID: 35740973 PMCID: PMC9220994 DOI: 10.3390/biom12060848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 01/27/2023] Open
Abstract
Dedifferentiation and proliferation of retinal pigment epithelial (RPE) cells are characteristics of retinal diseases. Dedifferentiation is likely associated with changes of inwardly rectifying potassium (Kir) channels. The roles of Kir4.2 channels in viability, and proliferation of cultured RPE cells were investigated. Gene expression levels were determined using qRT-PCR. RPE cells expressed Kir2.1, 2.2, 2.4, 3.2, 4.1, 4.2, 6.1, and 7.1 mRNA. Kir4.2 protein was verified by immunocytochemistry and Western blotting. Kir4.2 mRNA in cultured cells was upregulated by hypoxia (hypoxia mimetic CoCl2 or 0.2% O2) and extracellular hyperosmolarity (addition of high NaCl or sucrose). Kir4.2 mRNA was suppressed by vascular endothelial growth factor (VEGF), blood serum, and thrombin whereas platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), and transforming growth factor-β1 (TGF-β1) increased it. Hyperosmotic Kir4.2 gene expression was mediated by TGF-β1 receptor signaling while hypoxic gene transcription was dependent on PDGF receptor signaling. VEGF receptor-2 blockade increased Kir4.2 mRNA level under control, hyperosmotic, and hypoxic conditions. SiRNA-mediated knockdown of Kir4.2 decreased the cell viability and proliferation under control and hyperosmotic conditions. Kir4.2 channels play functional roles in maintaining the viability and proliferation of RPE cells. Downregulation of Kir4.2 by VEGF, via activation of VEGF receptor-2 and induction of blood-retinal barrier breakdown, may contribute to decreased viability of RPE cells under pathological conditions.
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Affiliation(s)
- Marie-Christin Beer
- Department of Ophthalmology and Eye Hospital, University of Leipzig, 04103 Leipzig, Germany; (M.-C.B.); (L.K.); (P.W.); (A.B.)
| | - Heidrun Kuhrt
- Institute of Anatomy, University of Leipzig, 04103 Leipzig, Germany;
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, 04103 Leipzig, Germany; (M.-C.B.); (L.K.); (P.W.); (A.B.)
- Department of Ophthalmology, Helios Klinikum Aue, 08280 Aue, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, 04103 Leipzig, Germany; (M.-C.B.); (L.K.); (P.W.); (A.B.)
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, 04103 Leipzig, Germany; (M.-C.B.); (L.K.); (P.W.); (A.B.)
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, 04103 Leipzig, Germany; (M.-C.B.); (L.K.); (P.W.); (A.B.)
- Correspondence:
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Li J, Lu X, Wei L, Ye D, Lin J, Tang X, Cui K, Yu S, Xu Y, Liang X. PHD2 attenuates high-glucose-induced blood retinal barrier breakdown in human retinal microvascular endothelial cells by regulating the Hif-1α/VEGF pathway. Inflamm Res 2021; 71:69-79. [PMID: 34773469 DOI: 10.1007/s00011-021-01518-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE Diabetic macular edema (DME) is one of the most frequent causes of severe vision loss. The pathogenesis of DME is still not fully understood; however, it is hypothesized to result from breakdown of the blood-retinal barrier (BRB) due to retinal inflammation by vascular endothelial growth factor (VEGF) secretion under hyperglycemic conditions. In this investigation, we discovered that Prolyl-4-hydroxylase 2 (PHD2), an upstream regulator of hypoxia-inducible factor 1 (HIF-1) modulates VEGF expression and thus preserves BRB function in the mouse retina. MATERIALS AND METHODS Primary human retinal microvascular endothelial cells (hRMECs) were cultured in human endothelial serum-free growth medium and exposed to hyperglycemia. Changes in cell viability were investigated by an MTT assay. BRB function in each group was revealed by a paracellular permeability assay and trans-endothelial electrical resistance (TEER). Morphological changes in the BRB were investigated by immunofluorescence staining of occludin and zonula occludens-1 (ZO-1). The mRNA and protein levels of the tight junction proteins, PHD2, HIF-1α, and VEGF were measured by reverse transcription-quantitative PCR (RT-qPCR), western blot analysis and ELISA. RESULTS Under hyperglycemic conditions, the viability of hRMECs was decreased, and PHD2 expression was downregulated, accompanied by increased paracellular permeability and decreased trans-endothelial electrical resistance. Additionally, HIF-1α and VEGF expression levels were increased, whereas the expression levels of tight junction proteins, including occludin and ZO-1, were decreased and BRB function was compromised. The PHD2 activator R59949 (diacylglycerol kinase inhibitor II), altered these pathological changes, and the PHD2 inhibitor dimethyloxalylglycine (DMOG) resulted in the opposite effects. CONCLUSION These results demonstrated that PHD2 inhibited HIF-1 activity by inhibiting HIF-1α expression in hRMECs under hyperglycemic conditions, which led to the downregulation of the expression of the angiogenic factor VEGF, and thus helped to maintain the functions of hRMECs. Therefore, it is reasonable to propose that PHD2 could be a potential novel target for the treatment of DME or other diseases with a similar pathogenesis.
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Affiliation(s)
- Jia Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Xi Lu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Liqing Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
- Eye Hospital of Wenzhou Medical University, Hangzhou Xihu Zhijiang Eye Hospital, No.7 Jinsui Rd, Hangzhou, Zhejiang, People's Republic of China, 310024
| | - Dan Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Jianqiang Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Xiaoyu Tang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Kaixuan Cui
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Shanshan Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030
| | - Yue Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030.
| | - Xiaoling Liang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Rd, Tianhe District, Guangzhou, Guangdong, People's Republic of China, 510030.
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Klose E, Kuhrt H, Kohen L, Wiedemann P, Bringmann A, Hollborn M. Hypoxic and osmotic expression of Kir2.1 potassium channels in retinal pigment epithelial cells: Contribution to vascular endothelial growth factor expression. Exp Eye Res 2021; 211:108741. [PMID: 34425102 DOI: 10.1016/j.exer.2021.108741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 07/22/2021] [Accepted: 08/19/2021] [Indexed: 12/31/2022]
Abstract
Retinal pigment epithelial (RPE) cells express different subtypes of inwardly rectifying potassium (Kir) channels. We investigated whether human and rat RPE cells express genes of strongly rectifying Kir2 channels. We also determined the hypoxic and hyperosmotic regulation of Kir2.1 gene expression in cultured human RPE cells and the effects of siRNA-mediated knockdown of Kir2.1 on VEGFA expression, VEGF secretion, proliferation, and viability of the cells. Extracellular hyperosmolarity was induced by addition of NaCl or sucrose. Hypoxia and chemical hypoxia were produced by cell culture in 0.25% O2 and addition of CoCl2, respectively. Gene expression levels were evaluated by real-time RT-PCR. Rat RPE cells contained Kir2.1, Kir2.2, Kir2.3, and Kir2.4 gene transcripts while human RPE cells contained Kir2.1, Kir2.2, and Kir2.4 transcripts. Immunocytochemical data may suggest that Kir2.1 protein in cultured human cells is expressed in both perinuclear and plasma membranes. Kir2.1 gene expression and Kir2.1 protein level in human cells increased under hypoxic and hyperosmotic conditions. The expression of the Kir2.1 gene was mediated in part by diverse intracellular signal transduction pathways and transcription factor activities under both conditions; the hyperosmotic, but not the CoCl2-induced Kir2.1 gene expression was dependent on intracellular calcium signaling. Autocrine/paracrine activation of purinergic receptors contributed to Kir2.1 gene expression under hyperosmotic (P2Y1, P2Y2, P2X7) and CoCl2-induced conditions (P2Y2, P2X7). Exogenous VEGF, TGF-β1, and blood serum decreased Kir2.1 gene expression. Inhibition of VEGF receptor-2 increased the Kir2.1 gene expression under control conditions and in CoCl2-simulated hypoxia, and decreased it under high NaCl conditions. Knockdown of Kir2.1 by siRNA inhibited the CoCl2-induced and hyperosmotic transcription of the VEGFA gene and caused a delayed decrease of the constitutive VEGFA gene expression while VEGF protein secretion was not altered. Kir2.1 knockdown stimulated RPE cell proliferation under control and hyperosmotic conditions without affecting cell viability. The data indicate that Kir2.1 channel activity is required for the expression of the VEGFA gene and inhibits the proliferation of RPE cells. Under control and hypoxic conditions, the extracellular VEGF level may regulate the production of VEGF via its inhibitory effect on the Kir2.1 gene transcription; this feedback loop may prevent overproduction of VEGF.
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Affiliation(s)
- Eva Klose
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Institute of Anatomy, University of Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany; Helios Klinikum Aue, Aue, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany.
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The role of actomyosin in the regulation of syndecan-1 in hyperosmosis. Biochim Biophys Acta Gen Subj 2021; 1865:129975. [PMID: 34343643 DOI: 10.1016/j.bbagen.2021.129975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/14/2021] [Accepted: 07/28/2021] [Indexed: 11/21/2022]
Abstract
INTRODUCTION The endothelial glycocalyx is susceptible to high concentration of glucose and sodium in the blood. These challenges often involve an increase in osmotic pressure which may independently alters the glycocalyx components. The glycocalyx anchors on the cell membrane via core proteins that link with the actin cytoskeleton. This study aims to investigate the role of actomyosin in the osmoregulation of syndecan-1, a core protein that bears abundant sugar chains of the glycocalyx. METHODS Human umbilical vein endothelial cells were incubated with mannitol-based hyperosmotic medium up to 2 h. The surface expression of syndecan-1 and the actin cytoskeleton were analysed by confocal microscopy, either without or with cytoskeletal manipulation. RESULTS Syndecan-1 expression was compromised when hyperosmotic challenge was prolonged for 2 h, with the normalised intensity substantially dropped to 65.78 ± 2.07% at +200 mOsm. The reduction is associated with a sustained actin hyper-polymerisation, including significant increases in cortex coverage and cytoskeletal tension. Disassembling the cortex by cytochalasin D restores syndecan-1 in hyperosmosis. Inhibition of ROCK, rather than MLCK and myosin II ATPase activity, prevents the reduction of syndecan-1. CONCLUSION We have demonstrated that prolonged hyperosmotic stress disrupts the integrity of syndecan-1 through an aberrant cortex polymerisation. Our results provide new evidence in the interplay between the glycocalyx and the actin. It helps us better interpret the regulation of the glycocalyx, moving towards a goal of protecting and restoring the glycocalyx under healthy and diseased conditions.
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Fernandez-Gonzalez P, Mas-Sanchez A, Garriga P. Polyphenols and Visual Health: Potential Effects on Degenerative Retinal Diseases. Molecules 2021; 26:3407. [PMID: 34199888 PMCID: PMC8200069 DOI: 10.3390/molecules26113407] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/26/2022] Open
Abstract
Dietary polyphenols are a group of natural compounds that have been proposed to have beneficial effects on human health. They were first known for their antioxidant properties, but several studies over the years have shown that these compounds can exert protective effects against chronic diseases. Nonetheless, the mechanisms underlying these potential benefits are still uncertain and contradictory effects have been reported. In this review, we analyze the potential effects of polyphenol compounds on some visual diseases, with a special focus on retinal degenerative diseases. Current effective therapies for the treatment of such retinal diseases are lacking and new strategies need to be developed. For this reason, there is currently a renewed interest in finding novel ligands (or known ligands with previously unexpected features) that could bind to retinal photoreceptors and modulate their molecular properties. Some polyphenols, especially flavonoids (e.g., quercetin and tannic acid), could attenuate light-induced receptor damage and promote visual health benefits. Recent evidence suggests that certain flavonoids could help stabilize the correctly folded conformation of the visual photoreceptor protein rhodopsin and offset the deleterious effect of retinitis pigmentosa mutations. In this regard, certain polyphenols, like the flavonoids mentioned before, have been shown to improve the stability, expression, regeneration and folding of rhodopsin mutants in experimental in vitro studies. Moreover, these compounds appear to improve the integration of the receptor into the cell membrane while acting against oxidative stress at the same time. We anticipate that polyphenol compounds can be used to target visual photoreceptor proteins, such as rhodopsin, in a way that has only been recently proposed and that these can be used in novel approaches for the treatment of retinal degenerative diseases like retinitis pigmentosa; however, studies in this field are limited and further research is needed in order to properly characterize the effects of these compounds on retinal degenerative diseases through the proposed mechanisms.
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Affiliation(s)
| | | | - Pere Garriga
- Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, 08222 Terrassa, Spain; (P.F.-G.); (A.M.-S.)
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Zhang P, Zhou YD, Tan Y, Gao L. Protective effects of piperine on the retina of mice with streptozotocin-induced diabetes by suppressing HIF-1/VEGFA pathway and promoting PEDF expression. Int J Ophthalmol 2021; 14:656-665. [PMID: 34012879 DOI: 10.18240/ijo.2021.05.04] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 02/18/2021] [Indexed: 02/05/2023] Open
Abstract
AIM To evaluate the protective mechanisms of piperine in the retina of mice with streptozotocin-induced diabetes. METHODS In experiments in vitro, stimulation by chemical hypoxia was established in ARPE-19 cells. Then, the expression of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGFA), and pigment epithelium-derived factor (PEDF) was assessed at the mRNA and protein levels. In experiments in vivo, diabetes mellitus was established by intraperitoneally injecting 150 mg/kg streptozotocin once. After 3wk of the onset of diabetes, 15 mg/kg piperine was intraperitoneally injected once daily for 1 or 3wk. Then, the retinal morphology and mRNA and protein expression were assessed. RESULTS In hypoxia, 1-100 µmol/L piperine significantly decreased the expression of VEGFA mRNA and increased the expression of PEDF mRNA without affecting HIF-1α mRNA. Meanwhile, 100 µmol/L piperine substantially decreased the protein level of VEGFA and increased the protein level of PEDF. The HIF-1α protein level was also hampered by piperine. In the diabetic retina of mice, the morphological damage was alleviated by piperine. Likewise, the retinal vascular leakage was substantially decreased by piperine. Further, the protein levels of HIF-1α and VEGFA were significantly reduced by piperine. Moreover, the level of the antiangiogenic factor of PEDF dramatically increased by piperine. CONCLUSION Piperine may exert protective effects on the retina of mice with diabetes via regulating the pro-antiangiogenic homeostasis composed of HIF-1/VEGFA and PEDF.
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Affiliation(s)
- Pu Zhang
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.,Changsha Aier Eye Hospital, Changsha 410015, Hunan Province, China
| | - Yan-Dan Zhou
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.,Changsha Aier Eye Hospital, Changsha 410015, Hunan Province, China
| | - Yao Tan
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
| | - Ling Gao
- Department of Ophthalmology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China
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11
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Liu AYL, Pek S, Low S, Moh A, Ang K, Tang WE, Lim Z, Subramaniam T, Sum CF, Lim SC. Association of overhydration and serum pigment epithelium-derived factor with CKD progression in diabetic kidney disease: A prospective cohort study. Diabetes Res Clin Pract 2021; 174:108754. [PMID: 33741351 DOI: 10.1016/j.diabres.2021.108754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/03/2021] [Accepted: 03/07/2021] [Indexed: 12/01/2022]
Abstract
AIM Little is known about whether overhydration (OH), measured using bioimpedance assay (BIA), is associated with CKD progression in patients with type 2 diabetes mellitus (T2DM). We hypothesised that OH was a predictor, and pigment epithelium-derived factor (PEDF) was a modifiable risk factor of CKD progression. METHODS We conducted a prospective cohort study of 1,065 patients with clinically euvolemic T2DM who attended the diabetes centre in a tertiary hospital or primary care clinic. CKD progression was defined as a combination of the worsening of the KDIGO defined CKD category by eGFR and a ≥25% decline in eGFR compared to baseline. RESULTS Patients with T2DM in the highest tertile of OH and relative OH (OH/ extracellular water > 7%) were positively associated with CKD progression (hazard ratio [HR] 1.45 [95% confidence interval (CI) 1.14-1.85; p = 0.003 and HR 1.29 [95%CI 1.05-1.59; p = 0.017]). There were positive associations between PEDF and CKD progression (β = 1.10; p = 0.001) and between OH and CKD progression (β = 0.21; p = 0.036). OH remained positively associated with CKD progression mediated by PEDF. CONCLUSIONS OH is an independent risk factor for CKD progression in patients with T2DM. Our study supports the novel definition of PEDF as a positive mediator between OH and CKD progression.
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Affiliation(s)
- Allen Yan Lun Liu
- Department of General Medicine, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore
| | - Sharon Pek
- Clinical Research Unit, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828, Singapore
| | - Serena Low
- Clinical Research Unit, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828, Singapore
| | - Angela Moh
- Clinical Research Unit, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828, Singapore
| | - Keven Ang
- Clinical Research Unit, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828, Singapore
| | - Wern Ee Tang
- National Healthcare Group Polyclinics, 3 Fusionopolis Link, Nexus@one-north, South Tower, Singapore 138543, Singapore
| | - Ziliang Lim
- National Healthcare Group Polyclinics, 3 Fusionopolis Link, Nexus@one-north, South Tower, Singapore 138543, Singapore
| | - Tavintharan Subramaniam
- Diabetes Centre, Admiralty Medical Centre, Block 676, Level 4, Kampung Admiralty, Woodlands Drive 71, Singapore 730676, Singapore
| | - Chee Fang Sum
- Diabetes Centre, Admiralty Medical Centre, Block 676, Level 4, Kampung Admiralty, Woodlands Drive 71, Singapore 730676, Singapore
| | - Su Chi Lim
- Clinical Research Unit, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828, Singapore; Diabetes Centre, Admiralty Medical Centre, Block 676, Level 4, Kampung Admiralty, Woodlands Drive 71, Singapore 730676, Singapore; Saw Swee Hock School of Public Health, National University of Singapore, 12 Science Drive 2, #10-01, Singapore 117549, Singapore.
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12
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Hyperosmolarity benefits cartilage regeneration by enhancing expression of chondrogenic markers and reducing inflammatory markers. In Vitro Cell Dev Biol Anim 2021; 57:290-299. [PMID: 33580417 DOI: 10.1007/s11626-020-00430-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 01/07/2020] [Indexed: 10/22/2022]
Abstract
Application of hyperosmolarity can be a promising strategy to promote chondrogenic differentiation in adipose-derived mesenchymal stem cells (ADSCs). Growth factors may promote different signaling pathways in parallel that is why in this study we monitor undesired pathologic or unwanted side effects as well as chondroinductive impacts of hyperosmolarity in differentiating ADSCs. Quantified gene expression, immunocytochemistry, glycosaminoglycan deposition and angiogenic secretion assays performed along with immunoassay. We observed that hyperosmolarity pressure of 480 mOsm over-expressed cartilage specific markers at gene expression level in the extra cellular matrix. Meanwhile, hyperosmolarity of 480 mOsm diminished the expression of cartilage associated pathologic markers, i.e., inflammatory and angiogenic attributes. Certain dose of hyperosmolarity could benefit chondrogenesis in a dual way, first by increasing chondrogenic markers and second by lowering tissue mineralization and angiogenic potential. The chondroprotective potential of hyperosmolarity could have a promising benefit in cartilage cell therapy and tissue engineering.
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13
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Schnabel B, Kuhrt H, Wiedemann P, Bringmann A, Hollborn M. Osmotic regulation of aquaporin-8 expression in retinal pigment epithelial cells in vitro: Dependence on K ATP channel activation. Mol Vis 2020; 26:797-817. [PMID: 33456300 PMCID: PMC7803296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 12/28/2020] [Indexed: 12/02/2022] Open
Abstract
PURPOSE The expression of aquaporin-8 (AQP8), which plays a crucial role in the maintenance of the cellular fluid and electrolyte balance, was shown to be increased in RPE cells under hyperosmotic conditions. The aim of the present study was to investigate the mechanisms of hyperosmotic AQP8 gene expression and the localization of AQP8 in cultured human RPE cells. METHODS Hyperosmolarity was produced with the addition of 100 mM NaCl or 200 mM sucrose. Hypoxia was induced by cell culture in a 0.2% O2 atmosphere or the addition of the hypoxia mimetic CoCl2. Oxidative stress was induced by the addition of H2O2. Gene expression was determined with real-time RT-PCR analysis. AQP8 protein localization and secretion of VEGF were evaluated with immunocytochemistry, western blotting, and enzyme-linked immunosorbent assay (ELISA). RESULTS Immunocytochemical and western blot data suggest that the AQP8 protein is mainly located in the mitochondria. Extracellular hyperosmolarity, hypoxia, and oxidative stress induced increases in AQP8 gene expression. Hyperosmotic AQP8 gene expression was reduced by inhibitors of the p38 MAPK and PI3K signal transduction pathways, and by JAK2 and PLA2 inhibitors, and was in part mediated by the transcriptional activity of CREB. Hyperosmotic AQP8 gene expression was also reduced by autocrine/paracrine interleukin-1 signaling, the sulfonylureas glibenclamide and glipizide, which are known inhibitors of KATP channel activation, and a pannexin-blocking peptide. The KATP channel opener pinacidil increased the expression of AQP8 under control conditions. The cells contained Kir6.1 and SUR2B gene transcripts and displayed Kir6.1 immunoreactivity. siRNA-mediated knockdown of AQP8 caused increases in hypoxic VEGF gene expression and secretion and decreased cell viability under control, hyperosmotic, and hypoxic conditions. CONCLUSIONS The data indicate that hyperosmotic expression of AQP8 in RPE cells is dependent on the activation of KATP channels. The data suggest that AQP8 activity decreases the hypoxic VEGF expression and improves the viability of RPE cells which may have impact for ischemic retinal diseases like diabetic retinopathy and age-related macular degeneration.
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Affiliation(s)
- Benjamin Schnabel
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Institute of Anatomy, Medical Faculty, University of Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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14
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Hollborn M, Brück R, Kuhrt H, Wiedemann P, Bringmann A. Osmotic and hypoxic induction of osteopontin in retinal pigment epithelial cells: Involvement of purinergic receptor signaling. Mol Vis 2020; 26:188-203. [PMID: 32214785 PMCID: PMC7086046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 03/06/2020] [Indexed: 10/26/2022] Open
Abstract
Purpose Osteopontin (OPN) is a neuroprotective factor in the retina that improves photoreceptor survival. The aim of the present study was to investigate whether human RPE cells express and respond to OPN. Methods Hypoxia and chemical hypoxia were induced by cell culture in 0.25% O2 and the addition of CoCl2, respectively. Hyperosmolarity was produced by the addition of 100 mM NaCl or 200 mM sucrose. Gene expression was quantified with real-time reverse transcription (RT)-PCR, and protein secretion was investigated with enzyme-linked immunosorbent assay (ELISA). Nuclear factor of activated T cell 5 (NFAT5) was depleted with siRNA. Results The acutely isolated RPE cells and the cultured RPE cells expressed OPN. OPN gene expression was induced by hypoxia and hyperosmotic media, as well as by exogenous bFGF. High extracellular NaCl and hypoxia induced secretion of OPN. Hyperosmotic expression of the OPN gene was mediated by the p38 MAPK and ERK1/2 signal transduction pathways, and the transcriptional activities of CREB and NFAT5. The hypoxic expression of the OPN gene was mediated by the PI3K signal transduction pathway and caspase-mediated, necrosis-related pathways. Phospholipases A2 were involved in mediating hyperosmotic and hypoxic OPN gene expression. Autocrine or paracrine P2Y2 receptor signaling induced by extracellular ATP contributed to hyperosmotic expression of the OPN gene whereas activation of A1 receptors by extracellularly formed adenosine contributed to thypoxic OPN gene expression. Autocrine or paracrine VEGF signaling exerted an inhibitory effect on expression of the OPN gene. Exogenous OPN induced expression and secretion of bFGF, but not of VEGF. Conclusions The data indicated that RPE cells produce and respond to OPN; OPN expression is, in part, induced by the cellular danger signal ATP. RPE-derived neuroprotective factors such as bFGF may contribute to the prosurvival effect of OPN on photoreceptor cells.
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Affiliation(s)
- Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Ricarda Brück
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Institute of Anatomy, University of Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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15
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Toth D, Szabo E, Tamas A, Juhasz T, Horvath G, Fabian E, Opper B, Szabo D, Maugeri G, D'Amico AG, D'Agata V, Vicena V, Reglodi D. Protective Effects of PACAP in Peripheral Organs. Front Endocrinol (Lausanne) 2020; 11:377. [PMID: 32765418 PMCID: PMC7381171 DOI: 10.3389/fendo.2020.00377] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 05/12/2020] [Indexed: 12/21/2022] Open
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide widely distributed in the nervous system, where it exerts strong neuroprotective effects. PACAP is also expressed in peripheral organs but its peripheral protective effects have not been summarized so far. Therefore, the aim of the present paper is to review the existing literature regarding the cytoprotective effects of PACAP in non-neuronal cell types, peripheral tissues, and organs. Among others, PACAP has widespread expression in the digestive system, where it shows protective effects in various intestinal pathologies, such as duodenal ulcer, small bowel ischemia, and intestinal inflammation. PACAP is present in both the exocrine and endocrine pancreas as well as liver where it reduces inflammation and steatosis by interfering with hepatic pathology related to obesity. It is found in several exocrine glands and also in urinary organs, where, with its protective effects being mainly published regarding renal pathologies, PACAP is protective in numerous conditions. PACAP displays anti-inflammatory effects in upper and lower airways of the respiratory system. In the skin, it is involved in the development of inflammatory pathology such as psoriasis and also has anti-allergic effects in a model of contact dermatitis. In the non-neuronal part of the visual system, PACAP showed protective effects in pathological conditions of the cornea and retinal pigment epithelial cells. The positive role of PACAP has been demonstrated on the formation and healing processes of cartilage and bone where it also prevents osteoarthritis and rheumatoid arthritis development. The protective role of PACAP was also demonstrated in the cardiovascular system in different pathological processes including hyperglycaemia-induced endothelial dysfunction and age-related vascular changes. In the heart, PACAP protects against ischemia, oxidative stress, and cardiomyopathies. PACAP is also involved in the protection against the development of pre-senile systemic amyloidosis, which is presented in various peripheral organs in PACAP-deficient mice. The studies summarized here provide strong evidence for the cytoprotective effects of the peptide. The survival-promoting effects of PACAP depend on a number of factors which are also shortly discussed in the present review.
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Affiliation(s)
- Denes Toth
- Department of Forensic Medicine, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Edina Szabo
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Andrea Tamas
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Tamas Juhasz
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Department of Biomedical and Biotechnological Sciences, Section of Human Anatomy and Histology, University of Catania, Catania, Italy
| | - Gabriella Horvath
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Eszter Fabian
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Balazs Opper
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Dora Szabo
- Heart Institute, Medical School, University of Pécs, Pécs, Hungary
| | - Grazia Maugeri
- Department of Biomedical and Biotechnological Sciences, Section of Human Anatomy and Histology, University of Catania, Catania, Italy
| | - Agata G. D'Amico
- Department of Drug Sciences, University of Catania, Catania, Italy
| | - Velia D'Agata
- Department of Biomedical and Biotechnological Sciences, Section of Human Anatomy and Histology, University of Catania, Catania, Italy
| | - Viktoria Vicena
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
| | - Dora Reglodi
- Department of Anatomy, MTA-PTE PACAP Research Team, University of Pécs Medical School, Pécs, Hungary
- *Correspondence: Dora Reglodi
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16
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Yu HF, Duan CC, Yang ZQ, Wang YS, Yue ZP, Guo B. HB-EGF Ameliorates Oxidative Stress-Mediated Uterine Decidualization Damage. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:6170936. [PMID: 31885807 PMCID: PMC6915015 DOI: 10.1155/2019/6170936] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 10/15/2019] [Accepted: 10/22/2019] [Indexed: 01/02/2023]
Abstract
HB-EGF is essential for uterine decidualization, but its antioxidant function remains largely unclear. Here, we found that HB-EGF promoted the proliferation of stromal cells followed by the accelerated transition of the cell cycle from G1 to S phase and enhanced the expression or activity of Prl8a2, Prl3c1, and ALP which were well-established markers for uterine stromal cell differentiation during decidualization. Under oxidative stress, stromal cell differentiation was impaired, but this impairment was abrogated by rHB-EGF accompanied with the reduced levels of ROS and MDA which were regarded as the biomarkers for oxidative stress, indicating an antioxidant role of HB-EGF. Further analysis revealed that HB-EGF enhanced the activities of antioxidant enzymes SOD, CAT, and GPX, where addition of GPX inhibitor MS attenuated the induction of rHB-EGF on Prl8a2, Prl3c1, and ALP. Meanwhile, HB-EGF rescued the content of GSH and restored the ratio of GSH/GSSG after exposure to H2O2 but did not alter NOX activity. Along with a decline for mitochondrial superoxide, exogenous rHB-EGF improved the damage of oxidative stress on mtDNA copy number, ATP level, mitochondrial membrane potential, and activities of mitochondrial respiratory chain complex I and III whose blockage by ROT and AA led to a failure of rHB-EGF in protecting stromal cell differentiation against injury. Moreover, HB-EGF prevented stromal cell apoptosis by inhibiting Caspase-3 activity and Bax expression and recovering the level of Bcl-2 mRNA. Collectively, HB-EGF might ameliorate oxidative stress-mediated uterine decidualization damage.
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Affiliation(s)
- Hai-Fan Yu
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Cui-Cui Duan
- Institute of Agro-Food Technology, Jilin Academy of Agricultural Sciences, Changchun, China
| | - Zhan-Qing Yang
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yu-Si Wang
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Zhan-Peng Yue
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Bin Guo
- College of Veterinary Medicine, Jilin University, Changchun, China
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17
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Fabian E, Reglodi D, Horvath G, Opper B, Toth G, Fazakas C, Vegh AG, Wilhelm I, Krizbai IA. Pituitary adenylate cyclase activating polypeptide acts against neovascularization in retinal pigment epithelial cells. Ann N Y Acad Sci 2019; 1455:160-172. [PMID: 31317557 DOI: 10.1111/nyas.14189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/30/2019] [Accepted: 06/14/2019] [Indexed: 12/31/2022]
Abstract
The purpose of this study was to determine whether pituitary adenylate cyclase activating polypeptide (PACAP) could influence the neovascularization processes in hyperosmotic and oxidative stress in retinal pigment epithelial cells. Hyperosmotic conditions and oxidative stress were induced by 200 mM sucrose and 250 µM hydrogen peroxide (H2 O2 ), respectively. Morphology and elasticity of adult retinal pigment epithelial (ARPE-19) cells were measured by atomic force microscopy, while the investigation of junctional molecules, such as occludin and ZO-1, was carried out using immunofluorescence. For cell viability measurement, the MTT test was used. The effect of PACAP on the key angiogenic factors, such as vascular endothelial growth factor, angiogenin, and endothelin-1, was measured by an angiogenesis array and flow cytometry. Hyperosmotic stress-induced reorganization of the cytoskeleton and impairment of the junctions decreased cell viability and upregulated several angiogenic factors. In oxidative stress, we found that opening of the junctions decreased viability and upregulated the expression of angiogenic factors. PACAP was shown to be protective in both conditions. Retinal pigment epithelium cells play an important role in several diseases, such as diabetic retinopathy and macular edema. Therefore, protecting retinal pigment epithelial (RPE) cells with PACAP could be a novel and potential treatment in these diseases.
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Affiliation(s)
- Eszter Fabian
- Department of Anatomy, University of Pécs, Medical School, MTA-PTE PACAP Research Group, Pécs, Hungary
| | - Dora Reglodi
- Department of Anatomy, University of Pécs, Medical School, MTA-PTE PACAP Research Group, Pécs, Hungary
| | - Gabriella Horvath
- Department of Anatomy, University of Pécs, Medical School, MTA-PTE PACAP Research Group, Pécs, Hungary
| | - Balazs Opper
- Department of Anatomy, University of Pécs, Medical School, MTA-PTE PACAP Research Group, Pécs, Hungary
| | - Gabor Toth
- Department of Medical Chemistry, University of Szeged, Szeged, Hungary
| | - Csilla Fazakas
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Attila G Vegh
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Imola Wilhelm
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Institute of Life Sciences, Vasile Goldiş Western University of Arad, Arad, Romania
| | - Istvan A Krizbai
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Institute of Life Sciences, Vasile Goldiş Western University of Arad, Arad, Romania
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18
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Osmotic induction of cyclooxygenase-2 in RPE cells: Stimulation of inflammasome activation. Mol Vis 2019; 25:329-344. [PMID: 31341381 PMCID: PMC6610242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 06/28/2019] [Indexed: 11/09/2022] Open
Abstract
Purpose Systemic hypertension is a risk factor of age-related macular degeneration, a disease associated with chronic retinal inflammation. The main cause of acute hypertension in the elderly is consumption of dietary salt (NaCl) resulting in increased extracellular osmolarity. The aim of the present study was to determine whether extracellular osmolarity regulates the expression of cyclooxygenase (COX) genes in cultured human retinal pigment epithelial (RPE) cells, and whether COX activity is involved in mediating the osmotic expression of key inflammatory (NLRP3 and IL1B) and angiogenic factor (VEGFA) genes. Methods Extracellular hyperosmolarity was induced by addition of NaCl or sucrose. Gene expression was determined with real-time reverse transcription (RT)-PCR. Cytosolic interleukin-1β (IL-1β) and extracellular vascular endothelial growth factor (VEGF) levels were evaluated with enzyme-linked immunosorbent assay (ELISA). Results Extracellular hyperosmolarity induced a dose-dependent increase in COX2 gene expression when >10 mM NaCl was added to the culture medium, while COX1 gene expression was increased at higher doses (>50 mM of added NaCl). Extracellular hypo-osmolarity decreased COX2 gene expression. High extracellular osmolarity also induced increases in the COX2 protein level. NaCl-induced expression of COX2 was mediated by various intracellular signal transduction molecules (p38 mitogen-activated protein kinase [p38 MAPK], extracellular signal-regulated kinases 1 and 2 [ERK1/2], and phosphatidylinositol-3 kinase [PI3K]), intracellular calcium signaling involving activation of phospholipase Cγ (PLCγ) and protein kinase Cα/β (PKCα/β), and the activity of nuclear factor of activated T cell 5 (NFAT5). Inhibition of fibroblast growth factor (FGF), transforming growth factor-β (TGF-β), and interleukin-1 (IL-1) receptor activities decreased NaCl-induced COX2 gene expression. Selective inhibition of COX2 activity decreased osmotic expression of the VEGFA, IL1B, and NLRP3 genes, and blocked the NaCl-induced increase in the cytosolic IL-1β level. Conclusions The expression of COX2 in RPE cells is osmoresponsive, and depends on NFAT5. COX2 activity stimulates hyperosmotic expression of angiogenic (VEGFA) and inflammatory factor (IL1B and NLRP3) genes, and activation of the NLRP3 inflammasome in RPE cells.
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19
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Szél E, Danis J, Sőrés E, Tóth D, Korponyai C, Degovics D, Prorok J, Acsai K, Dikstein S, Kemény L, Erős G. Protective effects of glycerol and xylitol in keratinocytes exposed to hyperosmotic stress. Clin Cosmet Investig Dermatol 2019; 12:323-331. [PMID: 31190939 PMCID: PMC6514140 DOI: 10.2147/ccid.s197946] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/25/2019] [Indexed: 12/14/2022]
Abstract
Purpose: Our goal was to study whether glycerol and xylitol provide protection against osmotic stress in keratinocytes. Methods: The experiments were performed on HaCaT keratinocytes. Hyperosmotic stress was induced by the addition of sorbitol (450, 500 and 600 mOsm). Both polyols were applied at two different concentrations (glycerol: 0.027% and 0.27%, xylitol: 0.045% and 0.45%). Cellular viability and cytotoxicity were assessed, intracellular Ca2+ concentration was measured, and the RNA expression of inflammatory cytokines was determined by means of PCR. Differences among groups were analyzed with one-way ANOVA and Holm-Sidak post-hoc test. When the normality test failed, Kruskal-Wallis one-way analysis of variance on ranks, followed by Dunn's method for pairwise multiple comparison was performed. Results: The higher concentrations of the polyols were effective. Glycerol ameliorated the cellular viability while xylitol prevented the rapid Ca2+ signal. Both polyols suppressed the expression of IL-1α but only glycerol decreased the expression of IL-1β and NFAT5. Conclusions: Glycerol and xylitol protect keratinocytes against osmotic stress. Despite their similar chemical structure, the effect of these polyols displayed differences. Hence, joint application of glycerol and xylitol may be a useful therapeutic approach for different skin disorders.
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Affiliation(s)
- Edit Szél
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Judit Danis
- MTA-SZTE Dermatological Research Group, Szeged, Hungary
| | - Evelin Sőrés
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Dániel Tóth
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Csilla Korponyai
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - Döníz Degovics
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
| | - János Prorok
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Károly Acsai
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | | | - Lajos Kemény
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary.,MTA-SZTE Dermatological Research Group, Szeged, Hungary
| | - Gábor Erős
- Department of Dermatology and Allergology, University of Szeged, Szeged, Hungary
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20
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Pawlowska E, Szczepanska J, Koskela A, Kaarniranta K, Blasiak J. Dietary Polyphenols in Age-Related Macular Degeneration: Protection against Oxidative Stress and Beyond. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9682318. [PMID: 31019656 PMCID: PMC6451822 DOI: 10.1155/2019/9682318] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/12/2019] [Indexed: 12/16/2022]
Abstract
Age-related macular degeneration (AMD) is a multifactorial disease of the retina featured by degeneration and loss of photoreceptors and retinal pigment epithelium (RPE) cells with oxidative stress playing a role in its pathology. Although systematic reviews do not support the protective role of diet rich in antioxidants against AMD, dietary polyphenols (DPs) have been reported to have beneficial effects on vision. Some of them, such as quercetin and cyanidin-3-glucoside, can directly scavenge reactive oxygen species (ROS) due to the presence of two hydroxyl groups in their B ring structure. Apart from direct ROS scavenging, DPs can lower oxidative stress in several other pathways. Many DPs induce NRF2 (nuclear factor, erythroid 2-like 2) activation and expression of phase II enzymes that are under transcriptional control of this factor. DPs can inhibit A2E photooxidation in RPE cells, which is a source of oxidative stress. Anti-inflammatory action of DPs in RPE cells is associated with regulation of various interleukins and signaling pathways, including IL-6/JAK2 (Janus kinase 2)/STAT3. Some DPs can improve impaired cellular waste clearance, including AMD-specific deficient phagocytosis of the Aβ42 peptide and autophagy.
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Affiliation(s)
- Elzbieta Pawlowska
- Department of Orthodontics, Medical University of Lodz, Pomorska 251, 92-216 Lodz, Poland
| | - Joanna Szczepanska
- Department of Pediatric Dentistry, Medical University of Lodz, Pomorska 251, 92-216 Lodz, Poland
| | - Ali Koskela
- Department of Ophthalmology, University of Eastern Finland, Kuopio 70211, Finland
- Department of Ophthalmology, Kuopio University Hospital, Kuopio 70029, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, Kuopio 70211, Finland
- Department of Ophthalmology, Kuopio University Hospital, Kuopio 70029, Finland
| | - Janusz Blasiak
- Department of Molecular Genetics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland
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Kleiner J, Hollborn M, Wiedemann P, Bringmann A. Activator protein-1 contributes to the NaCl-induced expression of VEGF and PlGF in RPE cells. Mol Vis 2018; 24:647-666. [PMID: 30310263 PMCID: PMC6178337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 10/07/2018] [Indexed: 11/05/2022] Open
Abstract
Purpose Systemic hypertension is a risk factor of neovascular age-related macular degeneration; consumption of dietary salt resulting in extracellular hyperosmolarity is a main cause of hypertension. Extracellular hyperosmolarity was shown to induce expression of angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), in RPE cells. The aim of the present study was to determine whether the hyperosmotic expression of growth factor genes in RPE cells is mediated by activator protein-1 (AP-1), and whether c-Fos and c-Jun genes are regulated by extracellular osmolarity. Methods Hyperosmotic media were made up with the addition of NaCl or sucrose. Gene expression was quantified with real-time reverse transcription (RT)-PCR, and protein secretion was investigated with enzyme-linked immunosorbent assay (ELISA). Nuclear factor of activated T cell 5 (NFAT5) was depleted with siRNA. DNA binding of AP-1 protein was evaluated with electrophoretic mobility shift assay (EMSA). Results High NaCl and the addition of sucrose triggered expression of the c-Fos gene, but not of the c-Jun gene. High NaCl also increased the levels of c-Fos and phosphorylated c-Jun proteins and the level of DNA binding of AP-1. Hypoosmolarity decreased the expression of the c-Fos and c-Jun genes. NaCl-induced expression of the c-Fos gene was in part mediated by NFAT5. Autocrine/paracrine activation of fibroblast growth factor and adenosine A1 receptors is involved in mediating NaCl-induced expression of the c-Fos gene. Pharmacological inhibition of the AP-1 activity decreased the NaCl-induced expression of the HIF-1α, NFAT5, VEGF, PlGF, and TGF-β2 genes, and prevented the NaCl-induced secretion of PlGF but not of VEGF. Conclusions The data indicate that AP-1 is activated in RPE cells in response to extracellular hyperosmolarity and mediates in part via the NaCl-induced expression of VEGF and PlGF, and secretion of PlGF. It is suggested that high consumption of dietary salt may exacerbate the angiogenic response of RPE cells in part via activation of AP-1.
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22
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Giummarra L, Crewther SG, Riddell N, Murphy MJ, Crewther DP. Pathway analysis identifies altered mitochondrial metabolism, neurotransmission, structural pathways and complement cascade in retina/RPE/ choroid in chick model of form-deprivation myopia. PeerJ 2018; 6:e5048. [PMID: 29967729 PMCID: PMC6026464 DOI: 10.7717/peerj.5048] [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: 02/19/2018] [Accepted: 05/31/2018] [Indexed: 12/15/2022] Open
Abstract
Purpose RNA sequencing analysis has demonstrated bidirectional changes in metabolism, structural and immune pathways during early induction of defocus induced myopia. Thus, the aim of this study was to investigate whether similar gene pathways are also related to the more excessive axial growth, ultrastructural and elemental microanalytic changes seen during the induction and recovery from form-deprivation myopia (FDM) in chicks and predicted by the RIDE model of myopia. Methods Archived genomic transcriptome data from the first three days of induction of monocularly occluded form deprived myopia (FDMI) in chicks was obtained from the GEO database (accession # GSE6543) while data from chicks monocularly occluded for 10 days and then given up to 24 h of normal visual recovery (FDMR) were collected. Gene set enrichment analysis (GSEA) software was used to determine enriched pathways during the induction (FDMI) and recovery (FDMR) from FD. Curated gene-sets were obtained from open access sources. Results Clusters of significant changes in mitochondrial energy metabolism, neurotransmission, ion channel transport, G protein coupled receptor signalling, complement cascades and neuron structure and growth were identified during the 10 days of induction of profound myopia and were found to correlate well with change in axial dimensions. Bile acid and bile salt metabolism pathways (cholesterol/lipid metabolism and sodium channel activation) were significantly upregulated during the first 24 h of recovery from 10 days of FDM. Conclusions The gene pathways altered during induction of FDM are similar to those reported in defocus induced myopia and are established indicators of oxidative stress, osmoregulatory and associated structural changes. These findings are also consistent with the choroidal thinning, axial elongation and hyperosmotic ion distribution patterns across the retina and choroid previously reported in FDM and predicted by RIDE.
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Affiliation(s)
- Loretta Giummarra
- School of Psychology & Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Sheila G Crewther
- School of Psychology & Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Nina Riddell
- School of Psychology & Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - Melanie J Murphy
- School of Psychology & Public Health, La Trobe University, Melbourne, Victoria, Australia
| | - David P Crewther
- Centre for Psychopharmacology, Swinburne University of Technology, Hawthorn, Victoria, Australia
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23
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Potential Interplay between Hyperosmolarity and Inflammation on Retinal Pigmented Epithelium in Pathogenesis of Diabetic Retinopathy. Int J Mol Sci 2018; 19:ijms19041056. [PMID: 29614818 PMCID: PMC5979527 DOI: 10.3390/ijms19041056] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/21/2018] [Accepted: 03/30/2018] [Indexed: 12/15/2022] Open
Abstract
Diabetic retinopathy is a frequent eyesight threatening complication of type 1 and type 2 diabetes. Under physiological conditions, the inner and the outer blood-retinal barriers protect the retina by regulating ion, protein, and water flux into and out of the retina. During diabetic retinopathy, many factors, including inflammation, contribute to the rupture of the inner and/or the outer blood-retinal barrier. This rupture leads the development of macular edema, a foremost cause of sight loss among diabetic patients. Under these conditions, it has been speculated that retinal pigmented epithelial cells, that constitute the outer blood-retinal barrier, may be subjected to hyperosmolar stress resulting from different mechanisms. Herein, we review the possible origins and consequences of hyperosmolar stress on retinal pigmented epithelial cells during diabetic retinopathy, with a special focus on the intimate interplay between inflammation and hyperosmolar stress, as well as the current and forthcoming new pharmacotherapies for the treatment of such condition.
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24
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Yu H, Zheng J, Liu X, Xue Y, Shen S, Zhao L, Li Z, Liu Y. Transcription Factor NFAT5 Promotes Glioblastoma Cell-driven Angiogenesis via SBF2-AS1/miR-338-3p-Mediated EGFL7 Expression Change. Front Mol Neurosci 2017; 10:301. [PMID: 28983240 PMCID: PMC5613209 DOI: 10.3389/fnmol.2017.00301] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 09/06/2017] [Indexed: 01/01/2023] Open
Abstract
Glioblastoma (GBM) is the most aggressive primary intracranial tumor of adults and confers a poor prognosis due to high vascularization. Hence anti-angiogenic therapy has become a promising strategy for GBM treatment. In this study, the transcription factor nuclear factor of activated T-cells 5 (NFAT5) was significantly elevated in glioma samples and GBM cell lines, and positively correlated with glioma WHO grades. Knockdown of NFAT5 inhibited GBM cell-driven angiogenesis. Furthermore, long non-coding RNA SBF2 antisense RNA 1 (SBF2-AS1) was upregulated in glioma samples and knockdown of SBF2-AS1 impaired GBM-induced angiogenesis. Downregulation of NFAT5 decreased SBF2-AS1 expression at transcriptional level. In addition, knockdown of SBF2-AS1 repressed GBM cell-driven angiogenesis via enhancing the inhibitory effect of miR-338-3p on EGF like domain multiple 7 (EGFL7). In vivo study demonstrated that the combination of NFAT5 knockdown and SBF2-AS1 knockdown produced the smallest xenograft volume and the lowest microvessel density. NFAT5/SBF2-AS1/miR-338-3p/EGFL7 pathway may provide novel targets for glioma anti-angiogenic treatment.
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Affiliation(s)
- Hai Yu
- Department of Neurosurgery, Shengjing Hospital of China Medical UniversityShenyang, China.,Liaoning Research Center for Clinical Medicine in Nervous System DiseaseShenyang, China.,Key laboratory of Neuro-oncology in Liaoning ProvinceShenyang, China
| | - Jian Zheng
- Department of Neurosurgery, Shengjing Hospital of China Medical UniversityShenyang, China.,Liaoning Research Center for Clinical Medicine in Nervous System DiseaseShenyang, China.,Key laboratory of Neuro-oncology in Liaoning ProvinceShenyang, China
| | - Xiaobai Liu
- Department of Neurosurgery, Shengjing Hospital of China Medical UniversityShenyang, China.,Liaoning Research Center for Clinical Medicine in Nervous System DiseaseShenyang, China.,Key laboratory of Neuro-oncology in Liaoning ProvinceShenyang, China
| | - Yixue Xue
- Department of Neurobiology, College of Basic Medicine, China Medical UniversityShenyang, China.,Key Laboratory of Cell Biology, Ministry of Public Health of China, and Key Laboratory of Medical Cell Biology, Ministry of Education of ChinaShenyang, China
| | - Shuyuan Shen
- Department of Neurobiology, College of Basic Medicine, China Medical UniversityShenyang, China.,Key Laboratory of Cell Biology, Ministry of Public Health of China, and Key Laboratory of Medical Cell Biology, Ministry of Education of ChinaShenyang, China
| | - Lini Zhao
- Department of Neurobiology, College of Basic Medicine, China Medical UniversityShenyang, China.,Key Laboratory of Cell Biology, Ministry of Public Health of China, and Key Laboratory of Medical Cell Biology, Ministry of Education of ChinaShenyang, China
| | - Zhen Li
- Department of Neurosurgery, Shengjing Hospital of China Medical UniversityShenyang, China.,Liaoning Research Center for Clinical Medicine in Nervous System DiseaseShenyang, China.,Key laboratory of Neuro-oncology in Liaoning ProvinceShenyang, China
| | - Yunhui Liu
- Department of Neurosurgery, Shengjing Hospital of China Medical UniversityShenyang, China.,Liaoning Research Center for Clinical Medicine in Nervous System DiseaseShenyang, China.,Key laboratory of Neuro-oncology in Liaoning ProvinceShenyang, China
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25
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Hollborn M, Fischer S, Kuhrt H, Wiedemann P, Bringmann A, Kohen L. Osmotic regulation of NFAT5 expression in RPE cells: The involvement of purinergic receptor signaling. Mol Vis 2017; 23:116-130. [PMID: 28356704 PMCID: PMC5360457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 03/16/2017] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Systemic hypertension is a risk factor for age-related neovascular retinal diseases. The major condition that induces hypertension is the intake of dietary salt (NaCl) resulting in increased extracellular osmolarity. High extracellular NaCl was has been shown to induce angiogenic factor production in RPE cells, in part via the transcriptional activity of nuclear factor of activated T cell 5 (NFAT5). Here, we determined the signaling pathways that mediate the osmotic expression of the NFAT5 gene in RPE cells. METHODS Cultured human RPE cells were stimulated with high (+100 mM) NaCl. Alterations in gene and protein expression were determined with real-time reverse transcriptase (RT)-PCR and western blot analysis, respectively. RESULTS NaCl-induced NFAT5 gene expression was fully inhibited by calcium chelation and blockers of inositol triphosphate (IP3) receptors and phospholipases C and A2. Blockers of phospholipases C and A2 also prevented the NaCl-induced increase of the cellular NFAT5 protein level. Inhibitors of multiple intracellular signaling transduction pathways and kinases, including p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Jun NH2-terminal kinase (JNK), phosphatidylinositol-3 kinase (PI3K), protein kinases A and C, Src tyrosine kinases, and calpains, as well as cyclooxygenase inhibitors, decreased the NaCl-induced expression of the NFAT5 gene. In addition, autocrine purinergic signaling mediated by a release of ATP and a nucleoside transporter-mediated release of adenosine, activation of P2X7, P2Y1, P2Y2, and adenosine A1 receptors, but not adenosine A2A receptors, is required for the full expression of the NFAT5 gene under hyperosmotic conditions. NaCl-induced NFAT5 gene expression is in part dependent on the activity of nuclear factor κB (NF-κB). The NaCl-induced expression of NFAT5 protein was prevented by inhibitors of phospholipases C and A2 and an inhibitor of NF-κB, but it was not prevented by a P2Y1 inhibitor. CONCLUSIONS The data suggest that in addition to calcium signaling and activation of inflammatory enzymes, autocrine/paracrine purinergic signaling contributes to the stimulatory effect of hyperosmotic stress on the expression of the NFAT5 gene in RPE cells. It is suggested that high intake of dietary salt induces RPE cell responses, which may contribute to age-related retinal diseases.
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Affiliation(s)
- Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Sarah Fischer
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Heidrun Kuhrt
- Paul Flechsig Institute of Brain Research, University of Leipzig Medical Faculty, Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany,Helios Klinikum Aue, Aue, Germany
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26
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Bringmann A, Hollborn M, Kohen L, Wiedemann P. Intake of dietary salt and drinking water: Implications for the development of age-related macular degeneration. Mol Vis 2016; 22:1437-1454. [PMID: 28031693 PMCID: PMC5178186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 12/20/2016] [Indexed: 10/26/2022] Open
Abstract
PURPOSE Systemic hypertension is a risk factor of age-related retinal diseases such as diabetic retinopathy and age-related macular degeneration. High intake of dietary salt and low intake of water increase extracellular osmolality resulting in hypertension, in particular in salt-sensitive individuals. This review summarizes the present knowledge regarding the impact of salt and water intake on the regulation of blood pressure, retinal function, and the development of age-related retinal diseases. METHODS A literature search of the Medline database and a summary of recent studies that used human RPE cells. RESULTS The salt sensitivity of the blood pressure and plasma osmolality increase with age, and body water deficits are common in older individuals. High plasma osmolality has adverse effects in the retina. In RPE cells, high osmolality induces expression and secretion of angiogenic factors, such as vascular endothelial growth factor (VEGF), placental growth factor, and basic fibroblast growth factor, and expression of aquaporin-5, a water channel implicated in transepithelial water transport. The transcriptional activities of hypoxia-inducible factor-1 (HIF-1) and nuclear factor of activated T cell 5 (NFAT5) are critical for the production of VEGF in response to salt-induced osmotic stress. Salt-induced osmotic stress also induces priming of the NLRP3 inflammasome and activates inflammatory enzymes in RPE cells. CONCLUSIONS Raised plasma osmolality may aggravate age-related retinal diseases by stimulation of local inflammation and angiogenic factor production in the RPE. Alterations in salt and water consumption, and of minerals that stimulate renal salt excretion, may offer nutritional approaches to prevent age-related retinal disorders, in particular in salt-sensitive individuals and individuals who show signs of body dehydration.
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Affiliation(s)
- Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany,Helios Klinikum Aue, Aue, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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P2Y1 Receptor Signaling Contributes to High Salt-Induced Priming of the NLRP3 Inflammasome in Retinal Pigment Epithelial Cells. PLoS One 2016; 11:e0165653. [PMID: 27788256 PMCID: PMC5082949 DOI: 10.1371/journal.pone.0165653] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 10/14/2016] [Indexed: 12/13/2022] Open
Abstract
Background Systemic hypertension is a risk factor of age-related macular degeneration (AMD), a chronic inflammatory disease. Acute hypertension is caused by increased extracellular osmolarity after intake of dietary salt (NaCl). We determined in cultured human retinal pigment epithelial (RPE) cells whether high extracellular NaCl alters the gene expression of inflammasome-associated proteins, and whether autocrine/paracrine purinergic (P2) receptor signaling contributes to the NaCl-induced NLRP3 gene expression. Methodology/Principal Findings Hyperosmolarity was induced by the addition of 100 mM NaCl or sucrose to the culture medium. Gene and protein expression levels were determined with real-time RT-PCR and Western blot analysis, respectively. IL-1β and IL-18 levels were evaluated with ELISA. Nuclear factor of activated T cell 5 (NFAT5) expression was knocked down with siRNA. High extracellular NaCl induced NLRP3 and pro-IL-1β gene expression, while the gene expression of further inflammasome-associated proteins (NLRP1, NLRP2, NLRP6, NLRP7, NLRP12, NLRC4, AIM2, ASC, procaspase-1, pro-IL-18) was not altered or below the detection threshold. The NaCl-induced NLRP3 gene expression was partially dependent on the activities of phospholipase C, IP3 receptors, protein kinase C, the serum and glucocorticoid-regulated kinase, p38 MAPK, ERK1/2, JNK, PI3K, and the transcription factors HIF-1 and NFAT5. Pannexin-dependent ATP release and P2Y1 receptor activation is required for the full induction of NLRP3 gene expression. High NaCl induced a transient increase of the NLRP3 protein level and a moderate NLRP3 inflammasome activation, as indicated by the transient increase of the cytosolic level of mature IL-1β. High NaCl also induced secretion of IL-18. Conclusion High extracellular NaCl induces priming of the NLRP3 inflammasome in RPE cells, in part via P2Y1 receptor signaling. The inflammasome priming effect of NaCl suggests that high intake of dietary salt may promote local retinal inflammation implicated in the development of AMD.
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Winges A, Garcia TB, Prager P, Wiedemann P, Kohen L, Bringmann A, Hollborn M. Osmotic expression of aldose reductase in retinal pigment epithelial cells: involvement of NFAT5. Graefes Arch Clin Exp Ophthalmol 2016; 254:2387-2400. [PMID: 27628063 DOI: 10.1007/s00417-016-3492-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 08/22/2016] [Accepted: 08/29/2016] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Diabetic retinopathy is associated with osmotic stress resulting from hyperglycemia and intracellular sorbitol accumulation. Systemic hypertension is a risk factor of diabetic retinopathy. High intake of dietary salt increases extracellular osmolarity resulting in systemic hypertension. We determined the effects of extracellular hyperosmolarity, chemical hypoxia, and oxidative stress on the gene expression of enzymes involved in sorbitol production and conversion in cultured human retinal pigment epithelial (RPE) cells. METHODS Alterations in the expression of aldose reductase (AR) and sorbitol dehydrogenase (SDH) genes were examined with real-time RT-PCR. Protein levels were determined with Western blot analysis. Nuclear factor of activated T cell 5 (NFAT5) was knocked down with siRNA. RESULTS AR gene expression in RPE cells was increased by high (25 mM) extracellular glucose, CoCl2 (150 μM)-induced chemical hypoxia, H2O2 (20 μM)-induced oxidative stress, and extracellular hyperosmolarity induced by addition of NaCl or sucrose. Extracellular hyperosmolarity (but not hypoxia) also increased AR protein level. SDH gene expression was increased by hypoxia and oxidative stress, but not extracellular hyperosmolarity. Hyperosmolarity and hypoxia did not alter the SDH protein level. The hyperosmotic AR gene expression was dependent on activation of metalloproteinases, autocrine/paracrine TGF-β signaling, activation of p38 MAPK, ERK1/2, and PI3K signal transduction pathways, and the transcriptional activity of NFAT5. Knockdown of NAFT5 or inhibition of AR decreased the cell viability under hyperosmotic (but not hypoxic) conditions and aggravated the hyperosmotic inhibition of cell proliferation. CONCLUSIONS The data suggest that sorbitol accumulation in RPE cells occurs under hyperosmotic, but not hypoxic and oxidative stress conditions. NFAT5- and AR-mediated sorbitol accumulation may protect RPE cells under conditions of osmotic stress.
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Affiliation(s)
- Anica Winges
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Tarcyane Barata Garcia
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Philipp Prager
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
- Helios Klinikum Aue, Aue, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, D-04103, Leipzig, Germany.
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Hollborn M, Reichmuth K, Prager P, Wiedemann P, Bringmann A, Kohen L. Osmotic induction of placental growth factor in retinal pigment epithelial cells in vitro: contribution of NFAT5 activity. Mol Biol Rep 2016; 43:803-14. [PMID: 27230578 DOI: 10.1007/s11033-016-4016-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 05/17/2016] [Indexed: 01/03/2023]
Abstract
One risk factor of neovascular age-related macular degeneration is systemic hypertension; hypertension is mainly caused by extracellular hyperosmolarity after consumption of dietary salt. In retinal pigment epithelial (RPE) cells, high extracellular osmolarity induces vascular endothelial growth factor (VEGF)-A (Hollborn et al. in Mol Vis 21:360-377, 2015). The aim of the present study was to determine whether extracellular hyperosmolarity and chemical hypoxia trigger the expression of further VEGF family members including placental growth factor (PlGF) in human RPE cells. Hyperosmotic media were made up by addition of 100 mM NaCl or sucrose. Chemical hypoxia was induced by CoCl2. Gene expression was quantified by real-time RT-PCR, and secretion of PlGF-2 was investigated with ELISA. Nuclear factor of activated T cell 5 (NFAT5) was depleted using siRNA. Extracellular hyperosmolarity triggered expression of VEGF-A, VEGF-D, and PlGF genes, and secretion of PlGF-2. Hypoosmolarity decreased PlGF gene expression. Hypoxia induced expression of VEGF-A, VEGF-B, VEGF-D, and PlGF genes. Extracellular hyperosmolarity and hypoxia produced additive PlGF gene expression. Both hyperosmolarity and hypoxia induced expression of KDR and FLT-4 receptor genes, while hyperosmolarity caused neuropilin-2 and hypoxia neuropilin-1 gene expression. The hyperosmotic, but not the hypoxic, PlGF gene expression was in part mediated by NFAT5. The expression of PlGF in RPE cells depends on the extracellular osmolarity. The data suggest that high consumption of dietary salt may exacerbate the angiogenic response of RPE cells in the hypoxic retina via transcriptional activation of various VEGF family member genes.
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Affiliation(s)
- Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany.
| | - Konrad Reichmuth
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany
| | - Philipp Prager
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany
| | - Peter Wiedemann
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany
| | - Leon Kohen
- Department of Ophthalmology and Eye Hospital, Faculty of Medicine, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany.,Helios Klinikum Aue, Aue, Germany
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