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Miazgowicz KL, Shocket MS, Ryan SJ, Villena OC, Hall RJ, Owen J, Adanlawo T, Balaji K, Johnson LR, Mordecai EA, Murdock CC. Age influences the thermal suitability of Plasmodium falciparum transmission in the Asian malaria vector Anopheles stephensi. Proc Biol Sci 2020; 287:20201093. [PMID: 32693720 PMCID: PMC7423674 DOI: 10.1098/rspb.2020.1093] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Models predicting disease transmission are vital tools for long-term planning of malaria reduction efforts, particularly for mitigating impacts of climate change. We compared temperature-dependent malaria transmission models when mosquito life-history traits were estimated from a truncated portion of the lifespan (a common practice) versus traits measured across the full lifespan. We conducted an experiment on adult female Anopheles stephensi, the Asian urban malaria mosquito, to generate daily per capita values for mortality, egg production and biting rate at six constant temperatures. Both temperature and age significantly affected trait values. Further, we found quantitative and qualitative differences between temperature-trait relationships estimated from truncated data versus observed lifetime values. Incorporating these temperature-trait relationships into an expression governing the thermal suitability of transmission, relative R0(T), resulted in minor differences in the breadth of suitable temperatures for Plasmodium falciparum transmission between the two models constructed from only An. stephensi trait data. However, we found a substantial increase in thermal niche breadth compared with a previously published model consisting of trait data from multiple Anopheles mosquito species. Overall, this work highlights the importance of considering how mosquito trait values vary with mosquito age and mosquito species when generating temperature-based suitability predictions of transmission.
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Affiliation(s)
- K L Miazgowicz
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA.,Center of Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA
| | - M S Shocket
- Biology Department, Stanford University, Stanford, CA, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - S J Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Lab, Department of Geography, University of Florida, Gainesville, FL, USA.,Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.,School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - O C Villena
- Computational Modeling and Data Analytics, Department of Statistics, Virginia Tech, Blacksburg, VA, USA
| | - R J Hall
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Center of Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA.,Odum School of Ecology, University of Georgia, Athens, GA, USA
| | - J Owen
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - T Adanlawo
- Odum School of Ecology, University of Georgia, Athens, GA, USA
| | - K Balaji
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | - L R Johnson
- Computational Modeling and Data Analytics, Department of Statistics, Virginia Tech, Blacksburg, VA, USA
| | - E A Mordecai
- Biology Department, Stanford University, Stanford, CA, USA
| | - C C Murdock
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA.,Center of Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA.,Odum School of Ecology, University of Georgia, Athens, GA, USA.,Center for Vaccines and Immunology, University of Georgia, Athens, GA, USA.,River Basin Center, University of Georgia, Athens, GA, USA.,Department of Entomology, Cornell University, Ithaca, NY, USA
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Evans KL, Ewen JG, Guillera-Arroita G, Johnson JA, Penteriani V, Ryan SJ, Sollmann R, Gordon IJ. Conservation in the maelstrom of Covid-19 - a call to action to solve the challenges, exploit opportunities and prepare for the next pandemic. Anim Conserv 2020; 23:235-238. [PMID: 32837242 PMCID: PMC7267322 DOI: 10.1111/acv.12601] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- K L Evans
- Department of Animal and Plant Sciences University of Sheffield Sheffield UK
| | - J G Ewen
- Institute of Zoology Zoological Society of London Regent's Park UK
| | | | - J A Johnson
- Department of Biological Sciences University of North Texas Denton TX USA
| | - V Penteriani
- Research Unit of Biodiversity (UMIB, CSIC-UO-PA) Mieres Spain
| | - S J Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Lab Department of Geography University of Florida Gainesville FL USA.,Emerging Pathogens Institute University of Florida Gainesville FL USA.,School of Life Sciences University of KwaZulu-Natal Durban South Africa
| | - R Sollmann
- Department of Wildlife, Fish, & Conservation Biology University of California Davis Davis CA USA
| | - I J Gordon
- James Hutton Institute Aberdeen UK.,Fenner School of Environment and Society The Australian National University Canberra ACT Australia.,Central Queensland University Townsville QLD Australia.,Land & Water CSIRO Townsville QLD Australia
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Ryan M, Ryan SJ. Chronic inflammatory demyelinating polyneuropathy: considerations for diagnosis, management, and population health. Am J Manag Care 2018; 24:S371-S379. [PMID: 30312032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
First described almost 50 years ago, chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare autoimmune disorder characterized by progressive peripheral neuropathy. CIDP is difficult to diagnose, but early diagnosis can be crucial to prevent permanent nerve damage. Initial treatment options include corticosteroids, immunoglobulin given by intravenous administration, and therapeutic plasma exchange. Subcutaneous administration of immunoglobulin provides a new option for patients with CIDP that has the potential to increase independence and improve tolerability. This article reviews the epidemiology, diagnosis, treatment options for first- and second-line therapy, treatment guidelines, and monitoring parameters for CIDP.
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Affiliation(s)
- Melody Ryan
- Professor, Department of Pharmacy Practice & Science, University of Kentucky College of Pharmacy, Lexington, KY.
| | - Stephen J Ryan
- Professor, Neuromuscular Medicine Program, Department of Neurology, University of Kentucky Medical Center, Lexington, KY.
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Abstract
Macrophage infiltration is frequent in the early stages of various proliferative eye disorders, including subretinal neovascularization. In this study, we set out to establish the origin of macrophages found in an animal model of laser-induced subretinal neovascularization. One primate received several intravenous injections of a colloidal carbon suspension. We then applied standard argon laser lesions to the retina of both eyes, which were enucleated eight days later and sectioned serially for histological examination. A quantitative estimate of carbon-laden and non-laden leukocytes was made based on morphological criteria. Mononuclear leukocytes accumulated in the laser lesions and the percentage of carbon-laden mononuclear leukocytes in relation to the total leukocyte number was higher in the extravascular area of the laser sites than in the systemic circulation. These findings indicate that the majority of mononuclear leukocytes that accumulate at the sites of laser lesions are derived from the systemic circulation.
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Affiliation(s)
- B Martini
- Department of Ophthalmology, Karolinska Hospital and Institute, Stockholm, Sweden
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Wilkinson I, Preston J, Ryan SJ, Szekely T, Trangmar P, Buckler A, Watson C, Grosvener W, Frost L, Scott F. 112THE MDTEA PODCAST - A NOVEL MEANS OF EDUCATING MULTI-DISCIPLINARY TEAMS ABOUT AGEING? Age Ageing 2017. [DOI: 10.1093/ageing/afx071.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Abstract
We have developed a reproducible model of traction retinal detachment in the rhesus monkey secondary to a penetrating eye injury. The model is characterized histologically by intravitreal fibroblastic proliferation and by epiretinal and by retroretinal membranes. Cells proliferating within the vitreous and in the epiretinal membranes have the ultrastructural characteristics of myofibroblasts. The presence of these contractile cells suggests that vitreous traction and the contraction of epiretinal membranes may be cell mediated. Our findings suggest that the pathophysiology of traction retinal detachment has many features in common with the normal process of wound healing and in particular with the mechanisms responsible for wound contraction and cicatrization.
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Gadient PM, Smith JH, Ryan SJ. Herpes zoster ophthalmicus following onabotulinumtoxinA administration for chronic migraine: a case report and literature review. Cephalalgia 2014; 35:443-8. [PMID: 25135654 DOI: 10.1177/0333102414544974] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND There is a growing body of literature documenting local herpes zoster outbreak following procedures. The mechanism underlying these outbreaks remains elusive. We present a case of zoster following onabotulinumtoxinA (BTX) for migraine and a literature review. METHODS Chart and literature review. CASE A 72-year-old woman with chronic migraine received BTX injections for 3 years without incident. She had a history of thoracic zoster with subsequent post-herpetic neuralgia. In August 2013, 48 hours after receiving BTX injections, she developed a painful rash in the right V1 distribution consistent with herpes zoster ophthalmicus. One week later the rash had resolved without treatment. LITERATURE REVIEW We identified 65 (including 2 from Juel-Jenson) cases of zoster reactivation following minor procedures. These cases tend to be in young patients without specific risk factors. Outbreaks characteristically occur at the level of exposure to local trauma. DISCUSSION Our review suggests that local trauma, regardless of the nature of stimuli, may be sufficient for zoster reactivation. We hypothesize that the stressors in these reported cases exert a local epigenetic influence on viral transcription, allowing for viral reactivation. CONCLUSION Zoster is a potential complication of BTX administration for chronic migraine in adults. Physician awareness can reduce the significant morbidity associated with this disease.
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Affiliation(s)
- Paul M Gadient
- University of Kentucky, Department of Neurology, KY, USA
| | | | - Stephen J Ryan
- University of Kentucky, Department of Neurology, KY, USA
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Sreekumar PG, Chothe P, Sharma KK, Baid R, Kompella U, Spee C, Kannan N, Manh C, Ryan SJ, Ganapathy V, Kannan R, Hinton DR. Antiapoptotic properties of α-crystallin-derived peptide chaperones and characterization of their uptake transporters in human RPE cells. Invest Ophthalmol Vis Sci 2013; 54:2787-98. [PMID: 23532520 DOI: 10.1167/iovs.12-11571] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The chaperone proteins, α-crystallins, also possess antiapoptotic properties. The purpose of the present study was to investigate whether 19 to 20-mer α-crystallin-derived mini-chaperone peptides (α-crystallin mini-chaperone) are antiapoptotic, and to identify their putative transporters in human fetal RPE (hfRPE) cells. METHODS Cell death and caspase-3 activation induced by oxidative stress were quantified in early passage hfRPE cells in the presence of 19 to 20-mer αA- or αB-crystallin-derived or scrambled peptides. Cellular uptake of fluorescein-labeled, α-crystallin-derived mini-peptides and recombinant full-length αB-crystallin was determined in confluent hfRPE. The entry mechanism in hfRPE cells for α-crystallin mini-peptides was investigated. The protective role of polycaprolactone (PCL) nanoparticle encapsulated αB-crystallin mini-chaperone peptides from H2O2-induced cell death was studied. RESULTS Primary hfRPE cells exposed to oxidative stress and either αA- or αB-crystallin mini-chaperones remained viable and showed marked inhibition of both cell death and activation of caspase-3. Uptake of full-length αB-crystallin was minimal while a time-dependent uptake of αB-crystallin-derived peptide was observed. The mini-peptides entered the hfRPE cells via the sodium-coupled oligopeptide transporters 1 and 2 (SOPT1, SOPT2). PCL nanoparticles containing αB-crystallin mini-chaperone were also taken up and protected hfRPE from H2O2-induced cell death at significantly lower concentrations than free αB-crystallin mini-chaperone peptide. CONCLUSIONS αA- and αB-crystallin mini-chaperones offer protection to hfRPE cells and inhibit caspase-3 activation. The oligopeptide transporters SOPT1 and SOPT2 mediate the uptake of these peptides in RPE cells. Nanodelivery of αB-crystallin-derived mini-chaperone peptide offers an alternative approach for protection of hfRPE cells from oxidant injury.
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Affiliation(s)
- Parameswaran G Sreekumar
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, USA
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Lee SY, Ryan SJ. Pathophysiology of Ocular Trauma. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00098-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abràmoff M, Abrams GW, Agarwal A, Ai E, Aiello LM, Aiello LP, Albert DM, Aschbrenner MW, Ávila M, Aylward GW, Bedell M, Belfort R, Bennett J, Bergstrom C, Besirli CG, Bhende PS, Binder S, Bird AC, Blodi BA, Blumenkranz MS, Boldt HC, Bornfeld N, Bottoni F, Boulton ME, Bowne SJ, Brantley MA, Bressler NM, Bressler SB, Bringmann A, Brinton DA, Brown GC, Brown JC, Brunner S, Bush RA, Cao D, Capone A, Carruthers D, Cavallerano JD, Chakravarthy U, Chan CC, Chan W, Charles S, Charteris DG, Chen DF, Chen J, Chen Y, Cheung CYL, Chew EY, Chiang A, Chiang MF, Constable IJ, Coscas G, Cruess AF, Cunningham ET, Curcio CA, Daiger SP, Damato BE, Davis JL, Davis MD, Day S, De Potter P, de Smet MD, Denniston AK, Dhaliwal RS, Ding X, Do DV, Dou G, Dunn WA, Ehlers JP, Engelbert M, Faia LJ, Falsini B, Fawzi AA, Fekrat S, Feldon SE, Fernandes RAB, Ferreyra HA, Ferrington DA, Ferris FL, Finger PT, Fisher SK, Fishman GA, Fleckenstein M, Flynn HW, Fok AC, Foulds WS, Freeman WR, Freton A, Friedlander M, Frishman LJ, Fu AD, Garcia Filho CADA, Garcia-Valenzuela E, Gaudric A, Gayed M, Genead MA, Gerding H, Giani A, Goldberg MF, Gombos DS, Gopal L, Gordon C, Goto H, Gragoudas ES, Grant MB, Green WR, Gregg RG, Gregor Z, Gregori G, Gregory-Evans K, Grob S, Groenewald C, Grossniklaus HE, Grover S, Gullapalli VK, Gupta A, Guthoff RF, Hahn P, Haller JA, Harbour JW, Haritoglou C, Hartnett ME, Hawkins BS, He S, Herwig MC, Heussen FM, Hinton DR, Holz FG, Houston SK, Hui YN, Humayun MS, Ikuno Y, Isaac D, Ishibashi T, Jabs DA, Jaffe GJ, Jampol LM, Joffe L, Johnson M, Johnson MW, Johnson RN, Joussen AM, Julian K, Jumper JM, Kaiser PK, Kampik A, Katamay R, Kay CN, Keane PA, Kenney MC, Khaderi KR, Khodair MA, Kim IK, Kim TW, Kirchhof B, Klein BE, Klein R, Konstantinidis L, Kozak I, Kuppermann BD, Labriola LT, Lai TY, Lam DS, Lam LA, Landers MB, Lane AM, Lavik EB, Leary JF, Lee SY, Lee TC, Leung LSB, Lewis DA, Lewis GP, Leys A, Li X, Liakopoulos S, Lin CP, Lin P, Liu DT, London NJ, Lujan BJ, Luo Y, Lutty GA, MacLaren R, Madreperla S, Maguire AM, Mainster MA, Mansfield NC, Markoe AM, Marmor MF, Martin DF, Massey SC, McCall MA, McCannel TA, McCutchan JA, McDonald HR, Mehta MP, Meier P, Merbs S, Meredith TA, Meyer CH, Mieler WF, Miller JW, Mirza RG, Mitter SK, Mittra RA, Miyake Y, Montemagno C, Moshiri A, Mruthyunjaya P, Muccioli C, Mullins RF, Murata T, Murphree AL, Murphy RP, Murray PI, Murray TG, Nagpal M, Namperumalsamy P, Nanda SK, Nguyen QD, Nussenblatt RB, Oh KT, Ohji M, Ohno-Matsui K, Palanker D, Patel PS, Pavlick AC, Peereboom DM, Pennesi ME, Pepose JS, Perry JD, Puliafito CA, Quiram PA, Raman R, Ramchandran RS, Rao HV, Rao NA, Rao PK, Rathinam SR, Recchia FM, Redmond KJ, Reh TA, Reichenbach A, Ritch R, Rosenfeld PJ, Rubin GS, Ruiz-Garcia H, Ryan SJ, Sadda SR, Sadun AA, Sakamoto T, Sampath AP, Schachat AP, Schmitz-Valckenberg S, Schwartz SG, Scott AW, Sebag J, Seddon JM, Sen HN, Sepah YJ, Sharma S, Sharma T, Sheu SJ, Shields CL, Shields JA, Shinoda K, Shukla D, Sieving PA, Silva PA, Silveira C, Singh AD, Smith SB, Smith WM, Sobrin L, Sodhi A, Sohn EH, Soubrane G, Spielberg L, Srivastava SK, Stachs O, Staurenghi G, Sternberg P, Stone EM, Sugino IK, Sullivan LS, Sullivan P, Sun JK, Sunness JS, Tadayoni R, Tang S, Terasaki H, Thomas MA, Thompson JT, Thumann G, Toth CA, Trese MT, Tsai JH, Turell ME, Turner PL, Udar N, Ulrich JN, Van Gelder RN, van Meurs JC, Vasconcelos-Santos DV, Vavvas DG, Vemulakonda GA, Wang H, Wang Y, Weiland JD, Weleber RG, Wharam MD, Wickham L, Wiedemann P, Wiley HE, Wilkinson C, Wilson DJ, Wolfensberger TJ, Wong D, Wong IY, Wong TY, Wu DM, Yandiev Y, Yang CH, Yang CM, Yannuzzi LA, Yasuda M, Yeh PT, Yehoshua Z, Yiu G, Yoon YH, Yu HG, Yuan A, Zarbin MA, Zhang JJ, Zhang K, Zhao M, Zhou P. Contributors. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00159-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ehrlich DE, Ryan SJ, Rainnie DG. Postnatal development of electrophysiological properties of principal neurons in the rat basolateral amygdala. J Physiol 2012; 590:4819-38. [PMID: 22848043 PMCID: PMC3487039 DOI: 10.1113/jphysiol.2012.237453] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/24/2012] [Indexed: 01/22/2023] Open
Abstract
The basolateral amygdala (BLA) is critically involved in the pathophysiology of psychiatric disorders, which often emerge during brain development. Several studies have characterized postnatal changes to the morphology and biochemistry of BLA neurons, and many more have identified sensitive periods of emotional maturation. However, it is impossible to determine how BLA development contributes to emotional development or the aetiology of psychiatric disorders because no study has characterized the physiological maturation of BLA neurons. We addressed this critical knowledge gap for the first time using whole-cell patch clamp recording in rat BLA principal neurons to measure electrophysiological properties at postnatal day (P)7, P10, P14, P21, P28 and after P35. We show that intrinsic properties of these neurons undergo significant transitions before P21 and reach maturity around P28. Specifically, we observed significant reductions in input resistance and membrane time constant of nearly 10-and 4-fold, respectively, from P7 to P28. The frequency selectivity of these neurons to input also changed significantly, with peak resonance frequency increasing from 1.0 Hz at P7 to 5.7 Hz at P28. In the same period, maximal firing frequency significantly increased and doublets and triplets of action potentials emerged. Concomitantly, individual action potentials became significantly faster, firing threshold hyperpolarized 6.7 mV, the medium AHP became faster and shallower, and a fast AHP emerged. These results demonstrate neurons of the BLA undergo vast change throughout postnatal development, and studies of emotional development and treatments for juvenile psychiatric disorders should consider the dynamic physiology of the immature BLA.
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Affiliation(s)
- D E Ehrlich
- Emory University School of Medicine, Department of Psychiatry and Behavioral Sciences, Division of Behavioral Neuroscience and Psychiatric Disorders, Yerkes Research Center, Atlanta, GA, USA
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Dou G, Sreekumar PG, Spee C, He S, Ryan SJ, Kannan R, Hinton DR. Deficiency of αB crystallin augments ER stress-induced apoptosis by enhancing mitochondrial dysfunction. Free Radic Biol Med 2012; 53:1111-22. [PMID: 22781655 PMCID: PMC3454510 DOI: 10.1016/j.freeradbiomed.2012.06.042] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 06/12/2012] [Accepted: 06/28/2012] [Indexed: 01/29/2023]
Abstract
Endoplasmic reticulum (ER) stress is linked to several pathological conditions including age-related macular degeneration. Excessive ER stress initiates cell death cascades which are mediated, in part, through mitochondrial dysfunction. Here, we identify αB crystallin as an important regulator of ER stress-induced cell death. Retinal pigment epithelial (RPE) cells from αB crystallin (-/-) mice, and human RPE cells transfected with αB crystallin siRNA, are more vulnerable to ER stress induced by tunicamycin. ER stress-mediated cell death is associated with increased levels of reactive oxygen species, depletion of glutathione in mitochondria, decreased superoxide dismutase activity, increased release of cytochrome c, and activation of caspases 3 and 4. The ER stress signaling inhibitors, salubrinal and 4-(2-aminoethyl) benzenesulfonyl fluoride, decrease mitochondrial damage and reduce RPE apoptosis induced by ER stress. Prolonged ER stress decreases levels of αB crystallin, thus exacerbating mitochondrial dysfunction. Overexpression of αB crystallin protects RPE cells from ER stress-induced apoptosis by attenuating increases in Bax, CHOP, mitochondrial permeability transition, and cleaved caspase 3. Thus, these data collectively demonstrate that αB crystallin provides critical protection of mitochondrial function during ER stress-induced RPE apoptosis.
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Affiliation(s)
- Guorui Dou
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Parameswaran G Sreekumar
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
| | - Christine Spee
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
| | - Shikun He
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
- Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
| | - Stephen J Ryan
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
| | - Ram Kannan
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
| | - David R Hinton
- Arnold and Beckman Macular Research Center, Doheny Eye Institute, 1355 San Pablo St, Los Angeles, CA 90033, USA
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
- Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, CA, 90033, USA
- Corresponding Author: David R Hinton MD, Department of Pathology, 2011 Zonal Avenue, HMR 209, Los Angeles, CA 90033, USA. Tel.: + 1 323 442 6617; Fax: + 1 323 442 6688.
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Ryan SJ. Interview with Stephen J. Ryan, MD, by George B. Bartley, MD. Arch Ophthalmol 2012; 130:650-651. [PMID: 22652853 DOI: 10.1001/archophthalmol.2012.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Stephen J Ryan
- Doheny Eye Institute, 1450 San Pablo St, Los Angeles, CA 90033, USA.
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Sreekumar PG, Spee C, Ryan SJ, Cole SPC, Kannan R, Hinton DR. Mechanism of RPE cell death in α-crystallin deficient mice: a novel and critical role for MRP1-mediated GSH efflux. PLoS One 2012; 7:e33420. [PMID: 22442691 PMCID: PMC3307734 DOI: 10.1371/journal.pone.0033420] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 02/14/2012] [Indexed: 11/26/2022] Open
Abstract
Absence of α-crystallins (αA and αB) in retinal pigment epithelial (RPE) cells renders them susceptible to oxidant-induced cell death. We tested the hypothesis that the protective effect of α-crystallin is mediated by changes in cellular glutathione (GSH) and elucidated the mechanism of GSH efflux. In α-crystallin overexpressing cells resistant to cell death, cellular GSH was >2 fold higher than vector control cells and this increase was seen particularly in mitochondria. The high GSH levels associated with α-crystallin overexpression were due to increased GSH biosynthesis. On the other hand, cellular GSH was decreased by 50% in murine retina lacking αA or αB crystallin. Multiple multidrug resistance protein (MRP) family isoforms were expressed in RPE, among which MRP1 was the most abundant. MRP1 was localized to the plasma membrane and inhibition of MRP1 markedly decreased GSH efflux. MRP1-suppressed cells were resistant to cell death and contained elevated intracellular GSH and GSSG. Increased GSH in MRP1-supressed cells resulted from a higher conversion of GSSG to GSH by glutathione reductase. In contrast, GSH efflux was significantly higher in MRP1 overexpressing RPE cells which also contained lower levels of cellular GSH and GSSG. Oxidative stress further increased GSH efflux with a decrease in cellular GSH and rendered cells apoptosis-prone. In conclusion, our data reveal for the first time that 1) MRP1 mediates GSH and GSSG efflux in RPE cells; 2) MRP1 inhibition renders RPE cells resistant to oxidative stress-induced cell death while MRP1 overexpression makes them susceptible and 3) the antiapoptotic function of α-crystallin in oxidatively stressed cells is mediated in part by GSH and MRP1. Our findings suggest that MRP1 and α crystallin are potential therapeutic targets in pathological retinal degenerative disorders linked to oxidative stress.
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Affiliation(s)
- Parameswaran G. Sreekumar
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States of America
| | - Christine Spee
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States of America
| | - Stephen J. Ryan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States of America
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Susan P. C. Cole
- Division of Cancer Biology and Genetics, Queen's University Cancer Research Institute, Kingston, Canada
| | - Ram Kannan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States of America
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - David R. Hinton
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, California, United States of America
- Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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15
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Xu J, Zhu D, Sonoda S, He S, Spee C, Ryan SJ, Hinton DR. Over-expression of BMP4 inhibits experimental choroidal neovascularization by modulating VEGF and MMP-9. Angiogenesis 2012; 15:213-27. [PMID: 22392094 DOI: 10.1007/s10456-012-9254-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 02/06/2012] [Indexed: 12/15/2022]
Abstract
Bone morphorgenetic protein (BMP)-4 has been shown to play a pivotal role in eye development; however, its role in mature retina or ocular angiogenic diseases is unclear. Activating downstream Smad signaling, BMP4 can be either pro-angiogenic or anti-angiogenic, depending on the context of cell types and associated microenvironment. In this study, we generated transgenic mice over-expressing BMP4 in retinal pigment epithelial (RPE) cells (Vmd2-Bmp4 Tg mice), and used the laser-induced choroidal neovascularization (CNV) model to study the angiogenic properties of BMP4 in adult eyes. Vmd2-Bmp4 Tg mice displayed normal retinal histology at 10 weeks of age when compared with age-matched wildtype mice. Over-expression of BMP4 in RPE in the transgenic mice was confirmed by real-time PCR and immunostaining. Elevated levels of Smad1,5 phosphorylation were found in BMP4 transgenic mice compared to wildype mice. Over-expression of BMP4 was associated with less severe CNV as characterized by fluorescein angiography, CNV volume measurement and histology. While control mice showed increased levels of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9 after laser injury, Vmd2-Bmp4 Tg showed no increase in either VEGF or MMP-9. Further, we found that TNF-induced MMP-9 secretion in vitro was reduced by pretreatment of RPE cells with BMP4. The inhibition of MMP-9 was Smad-dependent because BMP4 failed to repress TNF-induced MMP-9 expression when Smad1,5 was silenced by siRNA. In summary, our studies identified an anti-angiogenic role for BMP4 in laser-induced CNV, mediated by direct inhibition of MMP-9 and indirect inhibition of VEGF.
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Affiliation(s)
- Jing Xu
- Department of Ophthalmology, Keck School of Medicine, The University of Southern California, Los Angeles, CA 90089, USA
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Khankan R, Oliver N, He S, Ryan SJ, Hinton DR. Regulation of fibronectin-EDA through CTGF domain-specific interactions with TGFβ2 and its receptor TGFβRII. Invest Ophthalmol Vis Sci 2011; 52:5068-78. [PMID: 21571675 DOI: 10.1167/iovs.11-7191] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the role of fibronectin containing extra domain A (FN-EDA) in the pathogenesis of proliferative vitreoretinopathy (PVR) and the regulation of FN-EDA by transforming growth factor (TGF)-β and connective tissue growth factor (CTGF) in retinal pigment epithelial (RPE) cells. METHODS Expression of FN-EDA in normal human retinas and PVR membranes was evaluated by immunohistochemistry. The effects of TGFβ and CTGF on FN-EDA mRNA and protein expression in primary cultures of human RPE cells were analyzed at different time points by real-time PCR and Western blot, respectively. The interaction of CTGF with TGFβ2 or with its type II receptor TGFβRII was examined by ELISA, immunoprecipitation, and solid-phase binding assays. RESULTS FN-EDA was abundantly expressed in PVR membranes but absent from the RPE monolayer in normal human retinas. Treatment of RPE cells with TGFβ2 induced FN-EDA expression in a time- and dose-dependent manner, but CTGF alone had no effect. However, CTGF, through its N-terminal half fragment, augmented TGFβ2-induced expression of FN-EDA at the protein level. This effect was blocked by antibodies against TGFβ2 or TGFβRII. Interaction of TGFβ2 or TGFβRII with CTGF was dose dependent and specific. CTGF directly bound TGFβ2 and TGFβRII at its N- and C-terminal domains, respectively. CONCLUSIONS These findings suggest that CTGF promotes the profibrotic activities of TGFβ acting as a cofactor through direct protein interactions and complex regulatory mechanisms.
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Affiliation(s)
- Rima Khankan
- Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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17
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Shang Y, Cheng R, Dong L, Ryan SJ, Saha SP, Yu G. Cerebral monitoring during carotid endarterectomy using near-infrared diffuse optical spectroscopies and electroencephalogram. Phys Med Biol 2011; 56:3015-32. [PMID: 21508444 DOI: 10.1088/0031-9155/56/10/008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Intraoperative monitoring of cerebral hemodynamics during carotid endarterectomy (CEA) provides essential information for detecting cerebral hypoperfusion induced by temporary internal carotid artery (ICA) clamping and post-CEA hyperperfusion syndrome. This study tests the feasibility and sensitivity of a novel dual-wavelength near-infrared diffuse correlation spectroscopy technique in detecting cerebral blood flow (CBF) and cerebral oxygenation in patients undergoing CEA. Two fiber-optic probes were taped on both sides of the forehead for cerebral hemodynamic measurements, and the instantaneous decreases in CBF and electroencephalogram (EEG) alpha-band power during ICA clamping were compared to test the measurement sensitivities of the two techniques. The ICA clamps resulted in significant CBF decreases (-24.7 ± 7.3%) accompanied with cerebral deoxygenation at the surgical sides (n = 12). The post-CEA CBF were significantly higher (+43.2 ± 16.9%) than the pre-CEA CBF. The CBF responses to ICA clamping were significantly faster, larger and more sensitive than EEG responses. Simultaneous monitoring of CBF, cerebral oxygenation and EEG power provides a comprehensive evaluation of cerebral physiological status, thus showing potential for the adoption of acute interventions (e.g., shunting, medications) during CEA to reduce the risks of severe cerebral ischemia and cerebral hyperperfusion syndrome.
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Affiliation(s)
- Yu Shang
- Center for Biomedical Engineering, University of Kentucky, KY, USA
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Xu J, Zhu D, He S, Spee C, Ryan SJ, Hinton DR. Transcriptional regulation of bone morphogenetic protein 4 by tumor necrosis factor and its relationship with age-related macular degeneration. FASEB J 2011; 25:2221-33. [PMID: 21411747 DOI: 10.1096/fj.10-178350] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Bone morphogenetic protein-4 (BMP4) may be involved in the molecular switch that determines which late form of age-related macular degeneration (AMD) an individual develops. BMP4 expression is high in retinal pigment epithelium (RPE) cells in late, dry AMD patients, while BMP4 expression is low in the wet form of the disease, characterized by choroidal neovascularization (CNV). Here, we sought to determine the mechanism by which BMP4 is down-regulated in CNV. BMP4 expression was decreased within laser-induced CNV lesions in mice at a time when tumor necrosis factor (TNF) expression was high (7 d postlaser) and was reexpressed in RPE when TNF levels declined (14 d postlaser). We found that TNF, an important angiogenic stimulus, significantly down-regulates BMP4 expression in cultured human fetal RPE cells, ARPE-19 cells, and RPE cells in murine posterior eye cup explants. We identified two specificity protein 1 (Sp1) binding sites in the BMP4 promoter that are required for basal expression of BMP4 and its down-regulation by TNF. Through c-Jun NH(2)-terminal kinase (JNK) activation, TNF modulates Sp1 phosphorylation, thus decreasing its affinity to the BMP4 promoter. The down-regulation of BMP4 expression by TNF in CNV and mechanisms established might be useful for defining novel targets for AMD therapy.
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Affiliation(s)
- Jing Xu
- Neuroscience Graduate Program, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
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Sonoda S, Sreekumar PG, Kase S, Spee C, Ryan SJ, Kannan R, Hinton DR. Attainment of polarity promotes growth factor secretion by retinal pigment epithelial cells: relevance to age-related macular degeneration. Aging (Albany NY) 2009; 2:28-42. [PMID: 20228934 PMCID: PMC2837203 DOI: 10.18632/aging.100111] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2009] [Accepted: 12/26/2009] [Indexed: 12/13/2022]
Abstract
The
antiangiogenic and neurotrophic growth factor, pigment epithelial derived
factor (PEDF), and the proangiogenic growth factor, vascular endothelial
growth factor-A (VEGF), are released from retinal pigment epithelial (RPE)
cells where they play a critical role in the pathogenesis of age-related
macular degeneration (AMD). Since RPE polarity may be altered in advanced
AMD, we studied the effect of polarization of differentiated, human RPE
monolayer cultures on expression and secretion of PEDF and VEGF. Polarized
RPE demonstrated apical microvilli, expression of tight junction proteins,
apical localization of Na/K- ATPase, and high transepithelial resistance
(490 ± 17 Ω•cm2). PEDF secretion was about 1000 fold
greater than that for VEGF in both polarized and non-polarized cultures.
Polarization of the RPE monolayer increased PEDF secretion, which was
predominantly apical, by 34 fold (p<0.02) and VEGF secretion, which was
predominantly basolateral, by 5.7 fold (p<0.02). Treatment of
non-polarized RPE cultures with bone morphogenetic protein-4 (BMP-4) had no
effect on PEDF or VEGF secretion, but resulted in a dose-dependent
>2-fold increase in basolateral VEGF secretion (p<0.05) in polarized
cultures. Our data show that polarity is an important determinant of the
level of PEDF and VEGF secretion in RPE and support the contention that
loss of polarity of RPE in AMD results in marked loss of neurotrophic and
vascular support for the retina potentially leading to photoreceptor loss and
blindness.
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Affiliation(s)
- Shozo Sonoda
- Department of Ophthalmology, Keck School of Medicine of University of Southern California, Los Angeles, CA 90089, USA
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He S, Kumar SR, Zhou P, Krasnoperov V, Ryan SJ, Gill PS, Hinton DR. Soluble EphB4 inhibition of PDGF-induced RPE migration in vitro. Invest Ophthalmol Vis Sci 2009; 51:543-52. [PMID: 19696168 DOI: 10.1167/iovs.09-3475] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE EphB4 receptor (EphB4) and its ligand (EphrinB2) play an important role in the regulation of cell adhesion, growth, and migration. The purpose of this study was to determine the effects of EphB4 blockade by soluble EphB4 (sEphB4) on retinal pigment epithelial (RPE) cell migration and proliferation, induced by platelet-derived growth factor-BB (PDGF), and to establish its relevance to proliferative vitreoretinopathy (PVR). METHODS The expression of EphB4 and EphrinB2 in early-passage human RPE cells and in human PVR membranes was evaluated by confocal microscopy. The effect of sEphB4 (0.1-3 microg/mL) on PDGF (20 ng/mL)-induced RPE migration and proliferation was evaluated using a modified Boyden chamber assay and an MTT assay, respectively. Attachment to basement membrane matrix and fibronectin was assayed by MTT. Phosphorylation of FAK and p42/44 mitogen-activated protein kinase (MAPK) in retinal pigment epithelium was determined by Western blot analysis after exposure to sEphB4. The effect of sEphB4 on the phosphorylation of EphB4/EphrinB2 was demonstrated with the use of immunoprecipitation assays. RESULTS EphrinB2 and EphB4 were expressed on human RPE cells in vitro and in cells within human PVR membranes. sEphB4 blocked EphB4 and EphrinB2 phosphorylation in RPE cells in vitro. sEphB4 reduced RPE migration in response to PDGF stimulation (P < 0.01). Similarly, sEphB4 inhibited RPE attachment and proliferation in a dose-dependent manner (P < 0.05). PDGF-induced phosphorylation of FAK and MAPK was inhibited by sEphB4. CONCLUSIONS EphB4 and EphrinB2 are expressed in RPE cells and PVR membranes. sEphB4 inhibits PDGF-induced RPE cell attachment, proliferation, and migration. This effect may result from the inhibition of FAK and MAPK phosphorylation.
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Affiliation(s)
- Shikun He
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, USA
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Hua J, Spee C, Barron E, Kase S, Churchill AJ, Harper SJ, Ryan SJ, Bates DO, Hinton DR. VEGF165b inhibits choroidal neovascularization (CNV) in mouse model via intra‐vitreous and subcutaneous delivery. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.625.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jing Hua
- Physiology and PharmacologyUniversity of BristolBristolUnited Kingdom
- OphthalmologyDoheny Eye InstituteLos AngelesCA
| | | | | | - Satoru Kase
- OphthalmologyDoheny Eye InstituteLos AngelesCA
| | | | - Steven J Harper
- Physiology and PharmacologyUniversity of BristolBristolUnited Kingdom
| | | | - David O Bates
- Physiology and PharmacologyUniversity of BristolBristolUnited Kingdom
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Zhu D, Wu J, Spee C, Ryan SJ, Hinton DR. BMP4 mediates oxidative stress-induced retinal pigment epithelial cell senescence and is overexpressed in age-related macular degeneration. J Biol Chem 2009; 284:9529-39. [PMID: 19158083 DOI: 10.1074/jbc.m809393200] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The retinal pigment epithelium is a primary site of pathology in age-related macular degeneration. Oxidative stress and senescence are both thought to be important mediators of macular degeneration pathogenesis. We demonstrate here that bone morphogenetic protein-4 is highly expressed in the retinal pigment epithelium and adjacent extracellular matrix of patients with dry age-related macular degeneration. In vitro studies revealed that sublethal oxidative stress increased bone morphogenetic protein-4 expression in retinal pigment epithelial cells, and both bone morphogenetic protein-4 and persistent mild oxidative stress can induce retinal pigment epithelial cell senescence through p53-p21(Cip1/WAF1)-Rb pathway. We further demonstrate that bone morphogenetic protein-4 acts as a mediator in oxidative stress-induced senescence and that this mediator function is via Smad and the p38 signaling pathway to increase and activate p53 and p21(Cip1/WAF1) and decrease phospho-Rb. Oxidative stress-induced senescence can be blocked by Chordin-like, an antagonist of bone morphogenetic protein-4, or SB203580, a phospho-p38 inhibitor. Our results suggest that oxidative stress and bone morphogenetic protein-4 may interact to promote retinal pigment epithelial cell senescence and that bone morphogenetic protein-4 may represent a novel therapeutic target to inhibit the progressive effects of oxidative stress and senescence in dry age-related macular degeneration.
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Affiliation(s)
- Danhong Zhu
- Arnold and Mabel Beckman Macular Research Center, Keck School of Medicine of the University of Southern California, Los Angeles, California 90033, USA
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Sreekumar PG, Ding Y, Ryan SJ, Kannan R, Hinton DR. Regulation of thioredoxin by ceramide in retinal pigment epithelial cells. Exp Eye Res 2008; 88:410-7. [PMID: 18996115 DOI: 10.1016/j.exer.2008.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2008] [Revised: 09/16/2008] [Accepted: 10/10/2008] [Indexed: 12/01/2022]
Abstract
The purpose of this study was to determine the expression, regulation and signaling of a key redoxin family member thioredoxin 1 (Trx1) in normal, oxidant-stimulated and growth factor-pretreated RPE cells. Trx1 is expressed in early passage, human RPE cell cultures. RPE cells exposed to C(2)-ceramide for 24h showed no significant change in expression of Trx1 vs. controls with and without pretreatment for 24h with hepatocyte growth factor (HGF). Neither hypoxia from 1% O(2) or from CoCl(2) exposure resulted in any alteration in Trx1 expression in RPE cells. C(2)-ceramide treatment caused translocation of Trx1 from cytosol to the nucleus, which was abolished by pre-treatment of cells with a p38 MAPK-specific inhibitor. Furthermore, the gene and protein expression of thioredoxin interacting protein (Txnip) increased with ceramide treatment and was significantly (p<0.001) elevated with HGF preincubation vs. untreated controls. Prominent protection from ceramide-induced RPE cell death by exogenous rTrx1 was demonstrated. Although Trx1 directly interacts with its inhibitor, Txnip, p38 inhibition does not appear to have a role in this interaction. We found no direct interaction between apoptosis signal regulating kinase (ASK-1) and Txnip under the same experimental conditions. In summary, our data demonstrate the expression of Trx1 and Txnip in human RPE cells. Ceramide treatment results in translocation of Trx1 to the nucleus, and upregulation of Txnip expression; exogenous rTrx1 protects from ceramide-induced cell death. These results suggest that Trx1 and Txnip play an important role in the response of RPE to ceramide toxicity.
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Affiliation(s)
- Parameswaran G Sreekumar
- The Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
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He S, Chen Y, Khankan R, Barron E, Burton R, Zhu D, Ryan SJ, Oliver N, Hinton DR. Connective tissue growth factor as a mediator of intraocular fibrosis. Invest Ophthalmol Vis Sci 2008; 49:4078-88. [PMID: 18450591 DOI: 10.1167/iovs.07-1302] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the role of connective tissue growth factor (CTGF) in the pathogenesis of proliferative vitreoretinopathy (PVR). METHODS Expression of CTGF was evaluated immunohistochemically in human PVR membranes, and the accumulation of CTGF in the vitreous was evaluated by ELISA. The effects of CTGF on type I collagen mRNA and protein expression in RPE were assayed by real-time PCR and ELISA, and migration was assayed with a Boyden chamber assay. Experimental PVR was induced in rabbits with vitreous injection of RPE cells plus rhCTGF; injection of RPE cells plus platelet derived-growth factor, with or without rhCTGF, or by injection of RPE cells infected with an adenoviral vector that expressed CTGF. RESULTS CTGF was highly expressed in human PVR membranes and partially colocalized with cytokeratin-positive RPE cells. Treatment of RPE with rhCTGF stimulated migration with a peak response at 50 ng/mL (P < 0.05) and increased expression of type I collagen (P < 0.05). There was a prominent accumulation of the N-terminal half of CTGF in the vitreous of patients with PVR. Intravitreous injection of rhCTGF alone did not produce PVR, whereas such injections into rabbits with mild, nonfibrotic PVR promoted the development of dense, fibrotic epiretinal membranes. Similarly, intravitreous injection of RPE cells infected with adenoviral vectors that overexpress CTGF induced fibrotic PVR. Experimental PVR was associated with increased CTGF mRNA in PVR membranes and accumulation of CTGF half fragments in the vitreous. CONCLUSIONS The results identify CTGF as a major mediator of retinal fibrosis and potentially an effective therapeutic target for PVR.
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Affiliation(s)
- Shikun He
- Departments of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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Sreekumar PG, Zhou J, Sohn J, Spee C, Ryan SJ, Maurer BJ, Kannan R, Hinton DR. N-(4-hydroxyphenyl) retinamide augments laser-induced choroidal neovascularization in mice. Invest Ophthalmol Vis Sci 2008; 49:1210-20. [PMID: 18326751 DOI: 10.1167/iovs.07-0667] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate the effect of N-4-hydroxyphenyl retinamide (4-HPR) on experimental laser-induced choroidal neovascularization (CNV) and on the expression and secretion of relevant growth factors by cultured human retinal pigment epithelial (RPE) cells. METHODS CNV was induced by laser photocoagulation in C57BL/6 mice. 4-HPR (0.2 or 1 mg) or vehicle, was injected intraperitoneally twice daily for 14 days. Plasma and tissue levels of 4-HPR were measured by HPLC. CNV was evaluated by fluorescein angiography, histology, and quantitative confocal analysis of isolectin B4 histochemistry on days 7 and 14. Induction of apoptosis and expression and secretion of growth factors was studied in 4-HPR-treated RPE cultures. RESULTS Mice treated with 4-HPR exhibited time- and dose-dependent increases in plasma and tissue 4-HPR levels. CNV lesions showed increased volume with increased vascular leakage and contained fewer lesion-associated RPE in treated versus untreated mice. Treatment of nonpolarized RPE cultures with 4-HPR in the presence of serum resulted in RPE apoptosis; however, apoptosis was minimal in similarly treated highly polarized RPE. Treatment of RPE cells with 4-HPR resulted in the upregulation of VEGF-A and -C (P < 0.05) and Ang-1 (P < 0.01) mRNA and increased secretion of VEGF-A and -C (P < 0.05), whereas pigment epithelium-derived growth factor (PEDF) and thrombospondin (TSP)-1 mRNA expression and secretion were downregulated (P < 0.05). CONCLUSIONS 4-HPR increases lesion size and leakage in laser-induced CNV and is associated with the upregulation of key proangiogenic factors and the downregulation of antiangiogenic factors. Consistent with the preferential loss of RPE in CNV lesions in vivo, 4-HPR induces apoptosis of nonpolarized RPE in the presence of serum.
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Affiliation(s)
- Parameswaran G Sreekumar
- The Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Childrens Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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He S, Yaung J, Kim YH, Barron E, Ryan SJ, Hinton DR. Endoplasmic reticulum stress induced by oxidative stress in retinal pigment epithelial cells. Graefes Arch Clin Exp Ophthalmol 2008; 246:677-83. [DOI: 10.1007/s00417-008-0770-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/05/2008] [Accepted: 01/10/2008] [Indexed: 01/20/2023] Open
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Abstract
We outline current in vitro and in vivo models for experimental proliferative vitreoretinopathy (PVR) and provide a detailed protocol of our standardized in vivo PVR model. PVR is the leading cause of failed surgical procedures for the correction of rhegmatogenous retinal detachment. The pathogenesis of this multifactorial condition is still not completely understood. Experimental models for PVR help us understand the factors that play a role in the pathogenesis of the disease process in a controlled manner and allow for reproducible preclinical assessment of novel therapeutic interventions. We describe a cell injection model in detail that uses homologous retinal pigment epithelial (RPE) cell cultures to induce PVR over a 2-8 week period.
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Affiliation(s)
- Rajat N Agrawal
- Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
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He S, Incardona F, Jin M, Ryan SJ, Hinton DR. Thrombospondin-1 expression in RPE and choroidal neovascular membranes. Yan Ke Xue Bao 2006; 22:265-74. [PMID: 17378161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
PURPOSE To investigate the expression of thrombospondin 1 (TSP-1) in retinal pigment epithelium (RPE) and choroidal neovascular membranes (CNVMs) from patients with age-related macular degeneration (AMD). METHODS Tissue sections from normal human fetal and adult eyes and surgically removed CNVMs were immunostained for TSP-1 localization. Polymerase chain reaction and Western blotting were used to analyze TSP-1 mRNA and protein from human RPE cells, respectively. TSP-1 in the supernatant of cultured RPE cells and eye explants were measured using enzyme-linked immunosorbent assay. MTT assay was used to evaluate the RPE survival after TSP-1 treatment. RESULTS The strongest immunostaining for TSP-1 was observed in the RPE monolayer around drusen in early AMD. The intensity of TSP-1 staining in normal eye sections was much weaker than that of early AMD and CNVM. TSP-1 mRNA was positive in cultured fetal and adult RPE cells. There was increasing secretion of TSP-1 into the supernatant of cultured RPE and eye explants. The specific band of TSP-1 was identified by Western blot. No significant inhibition of RPE survival was found with the exposure to TSP-1. CONCLUSIONS TSP-1 expression in drusen and CNVM was upregulated and associated with RPE monolayer. TSP-1 may be a natural negative regulator for choroidal neovascularization.
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Affiliation(s)
- Shikun He
- Department of Pathology, Keck School of Medicine of the University of Southern California, Los Angeles 90033, USA
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Sreekumar PG, Kannan R, de Silva AT, Burton R, Ryan SJ, Hinton DR. Thiol regulation of vascular endothelial growth factor-A and its receptors in human retinal pigment epithelial cells. Biochem Biophys Res Commun 2006; 346:1200-6. [PMID: 16793007 DOI: 10.1016/j.bbrc.2006.06.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 06/03/2006] [Indexed: 01/09/2023]
Abstract
We investigated the secretion and expression of VEGF-A and its receptors in human retinal pigment epithelial cells (RPE) under conditions of oxidative stress induced by glutathione (GSH) depletion. RPE cells were treated with 500 microM DL-buthionine-(S,R)-sulfoximine (BSO) for varying times up to 24 h. Cellular GSH levels, GSH:GSSG ratios, VEGF-A mRNA and protein expression, as well as VEGF-A secretion, and VEGFR-1 and VEGFR-2 receptor expression were determined. Treatment with BSO caused a significant decrease in intracellular GSH and in GSH/GSSG ratios. Treatment with BSO increased VEGF-A mRNA linearly with time which was significant at 24h (p<0.01 vs untreated controls). An increase was also found for VEGF-A secretion with BSO treatment; incubation of RPE with GSH monoethyl ester (GSH-MEE) caused an 84% decrease in VEGF-A secretion. Further, thiol depletion by BSO caused a significant induction of VEGFR-1 and VEGFR-2. Thus, our studies show that cellular redox status plays an important role in VEGF regulation in RPE cells.
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Affiliation(s)
- Parameswaran G Sreekumar
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
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Affiliation(s)
- S J Ryan
- Department of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley, CA 94720, USA.
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Hoffmann S, He S, Ehren M, Ryan SJ, Wiedemann P, Hinton DR. MMP-2 and MMP-9 secretion by rpe is stimulated by angiogenic molecules found in choroidal neovascular membranes. Retina 2006; 26:454-61. [PMID: 16603966 DOI: 10.1097/01.iae.0000238549.74626.33] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Matrix metalloproteinases (MMP)-2 and -9 play an important role in the pathogenesis of choroidal neovascularization (CNV). Retinal pigment epithelial cells (RPE) are an important source of MMPs in the outer retinal environment, however little is known about the local factors that modulate MMP secretion in these cells. The purpose of this study was to determine the effects of CNV involved growth factors and the extracellular matrix molecule fibronectin on MMP-2 and -9 secretion by cultured human RPE. METHODS MMP-2 and -9 secretion was studied using gelatin zymography, Western blot, and ELISA assay of RPE culture supernatants. The effects of stimulating the cells for 36 hours with vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bGFG), tumor necrosis factor-alpha (TNF-alpha), or fibronectin (FN), all angiogenic factors found in CNV membranes, was determined. RESULTS Resting RPE cells secreted MMP-2 but not MMP-9. Stimulation with TNF-alpha induced secretion of MMP-9 and increased the secretion of MMP-2. MMP-2 secretion was also increased by stimulation with FN and VEGF, but not bFGF. CONCLUSION The results indicated that the angiogenic molecules VEGF, FN, and TNF-alpha stimulate MMP-2 and -9 secretion from RPE and thus further promote CNV.
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Affiliation(s)
- Stephan Hoffmann
- Beckman Macular Research Center at the Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA
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Gamulescu MA, Chen Y, He S, Spee C, Jin M, Ryan SJ, Hinton DR. Transforming growth factor beta2-induced myofibroblastic differentiation of human retinal pigment epithelial cells: regulation by extracellular matrix proteins and hepatocyte growth factor. Exp Eye Res 2006; 83:212-22. [PMID: 16563380 DOI: 10.1016/j.exer.2005.12.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 12/13/2005] [Accepted: 12/15/2005] [Indexed: 11/30/2022]
Abstract
Retinal pigment epithelial (RPE) cells possess the potential to transdifferentiate into myofibroblasts after stimulation with transforming growth factor beta (TGFbeta) and are implicated in the pathogenesis of proliferative vitreoretinopathy. In this study we evaluated how TGFbeta2 and various extracellular matrix (ECM) proteins modulate the transdifferentiation of human fetal retinal pigment epithelial cells (RPE) cells into myofibroblast-like cells. Furthermore, we investigated whether hepatocyte growth factor (HGF) can suppress this transdifferentiation. RPE cells were cultured on ECM coated or uncoated surfaces in the presence or absence of TGFbeta2. HGF was added to certain cultures only once or on a daily basis during the treatment. Transdifferentiation of RPE cells into myofibroblasts was assessed by the quantitation of alpha-smooth muscle actin (alpha-SMA) using immunocytochemistry, flow cytometry, real-time PCR and Western blotting. TGFbeta2 induced a significant increase of alpha-SMA expression in a dose-dependent manner. Compared with growth on uncoated surfaces, RPE cultured on fibronectin (FN)-coated surfaces and stimulated with TGFbeta2 showed a significantly higher alpha-SMA expression than untreated cells. This upregulation of alpha-SMA could be markedly reduced by daily treatment with HGF; however, a single HGF administration did not significantly reduce alpha-SMA. These findings are important for further understanding the interaction of cytokines, RPE cells and their environment in mesenchymal transformation as well as its possible modulation. Continuous or long-term treatment with HGF should be further investigated for its potential to prevent mesenchymal transdifferentiation of RPE cells, and ultimately, PVR in vivo.
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Affiliation(s)
- Maria-Andreea Gamulescu
- Doheny Eye Institute, Keck School of Medicine, University of Southern California, 1450 San Pablo Street, Los Angeles, CA 90033, USA.
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Ryan SJ, Hinton DR, Murata T. Choroidal Neovascularization. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50062-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Ryan SJ, Yoon YH. Posterior Segment Trauma: Open Globe. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50144-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
PURPOSE To investigate the involvement of carrier-mediated transport mechanisms in brimonidine transport in retinal pigment epithelium (RPE). METHODS The transport of [3H]-brimonidine in bovine RPE-choroid explants was evaluated in a modified Ussing chamber. The uptake of [3H]brimonidine was evaluated in differentiated ARPE-19 cells cultured on permeable transwell filters. RESULTS The transport of brimonidine into (choroid-to-retina transport [inward]) and out of (retina-to-choroid transport [outward]) the eye in bovine RPE-choroid explants was temperature dependent. Both inward and outward brimonidine transport decreased at 5 microM compared with 10 nM. The melanin pigmentation of RPE did not significantly affect tissue permeability at either brimonidine dose. A saturable component was identified for the inward transport with the apparent Michaelis-Menten constant and a maximum transport rate of 51 microM and 148 pmol/(cm2 x h), respectively. Both apical (representing retina-to-choroid transport) and basolateral (representing choroid-to-retina transport) brimonidine uptake in ARPE-19 cells showed temperature dependence. Apical uptake was higher than basolateral uptake at 37 degrees C and was decreased to 70% in the presence of NaN3 or in the absence of extracellular Na+. Besides alpha2-agonists, apical uptake was inhibited by verapamil, desipramine, and quinidine, but not by MPP+ (1-methyl-4-phenylpyridinium), TEA (tetraethylammonium), decynium-22, carnitine, PHA (p-aminohippurate), alanine, or inosine. Basolateral brimonidine uptake increased by 35% at extracellular pH of 6 and decreased by 50% under cell-depolarized conditions of high medium K+ and 1 microM valinomycin. Temperature-dependent components of basolateral uptake were not saturated at doses up to 2 mM. CONCLUSIONS A carrier-mediated transport process for brimonidine in RPE was demonstrated in bovine RPE-choroid explants and polarized ARPE-19 cells. This transport system may play a significant role in modulating the movement of brimonidine into and out of the eye.
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Affiliation(s)
- Ning Zhang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
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Aaberg TM, Abdel-Rahman MH, Abrams GW, Agarwal A, Ai E, Albert DM, Alexander J, Anand R, Anastassiou G, Aylward GW, Barazi MK, Bingaman D, Bird AC, Blodi BA, Blumenkranz MS, Bolling JP, Bornfeld N, Bressler SB, Bressler NM, Brinton DA, Brown J, Brown GC, Brown JC, Buettner H, de Bustros S, Byrne SF, Cahill MT, Campochiaro PA, Carr RE, Chang S, Charles S, Chen J, Chen CA, Chew EY, Chorich LJ, Chow DR, Ciardella AP, Ciulla TA, Coscas GJ, Cruess AF, da Cruz L, Damato BE, Davidorf FH, Davis MD, Davis JL, Deutman AF, Dhaliwal RS, Do DV, Dugel PU, Earle JD, Edwards AO, Eliott D, Emerson GG, Fekrat S, Feldon SE, Ferris FL, Fine SL, Finkelstein D, Fisher SK, Flannery J, Folk JC, Foulds WS, Frank RN, Freeman WR, Friedlander M, Frishman LJ, Fu AD, Fujii GY, Gallemore RP, Garibaldi DC, Garcia-Valenzuela E, Gass JDM, Gautier S, Geller S, Goldberg MF, Gonzales CR, Gottlieb JL, Gragoudas ES, Green RL, Green WR, Gregor ZJ, Gregory-Evans K, Gross NE, Gullapalli VK, Guyer DR, Guymer R, Haller JA, Harbour JW, Harlan JB, Harris A, Hartnett ME, Hartzer MK, Hawkins BS, Heimann H, Hinton DR, Hinz BJ, Hoffmann S, Holekamp NM, Holland GN, Hoyng CB, Humayun MS, Ikuno Y, Jabs DA, Jaffe GJ, Jallet V, Jampol LM, Joffe L, Johnson RN, Joseph DP, de Juan E, Michael Jumper J, Kaplan HJ, Kelley JS, Khodair MA, Kirchhof B, Klais CM, Klein BE, Klein R, Kline RW, Knox DL, Kosobucki BR, Kreiger AE, Kunimoto DY, Kwun RC, Lakhanpal RR, Lam LA, Landers MB, Lane AM, Lee MS, Lee HC, Lewis H, Lewis GP, Lim WK, Lit ES, Loewenstein A, Lopez JM, Lutty GA, Madreperla S, Maguire AM, Mainster MA, Mansfield NC, Marmor MF, Martin BJ, Massey SC, Mavrofrides EC, McCuen BW, Richard McDonald H, Meier P, Merbs SL, Meredith TA, Mieler WF, Miller RF, Miller JW, Milne P, Mittra RA, Moshfeghi DM, Moshfeghi AA, Moshiri A, Mruthyunjaya P, Murata T, Murphree AL, Murphy RP, Nanda SK, Nguyen QD, Nussenblatt RB, Ober MD, Ober RR, Ogden TE, Oh KT, Ohji M, Olsen KR, Palanker D, Palmer EA, Parel JM, Park CH, Pederson JE, Pelzek CD, Pepose JS, Phelps DL, Phillips S, Pokorny J, Puliafito CA, Rao NA, Kumar Rao P, Recchia FM, Reh TA, Robertson DM, Robertson JE, Rubin GS, Ryan SJ, Sadda SR, Sadun AA, Sahel JA, de la Maza MS, Samuel MA, Sanborn GE, Sarks JP, Sarks SH, Schachat AP, Sebag J, Seddon JM, Sharma S, Sheffield VC, Shields CL, Shields JA, Singh A, Sjaarda RN, Slakter JS, Smith VC, Smith RE, Solomon SD, Soubrane G, Spencer R, Sternberg P, Stewart JM, Stone EM, Sugino IK, Sunness JS, Tano Y, Tasman WS, Thomas MA, Thompson JT, Thorne JE, Thumann G, Toth CA, Trese MT, Tsai LM, Turner PL, Tweito TH, Updike PG, Van Gelder RN, van Lith-Verhoeven JJ, Vaudaux JD, Villain F, Vitale AT, Walker JD, Walsh AC, Wang H, Webster AR, Weiland JD, Weiter JJ, Weleber RG, Wharam MD, Jeffrey Whitehead A, Wiedemann P, Wilkinson C, Williams GA, Willson JK, Wilson DJ, Win PH, Yannuzzi LA, Yoon YH, Young TA, Zarbin MA, Zhang K. Contributors. Retina 2006. [DOI: 10.1016/b978-0-323-02598-0.50003-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Jin M, Yaung J, Kannan R, He S, Ryan SJ, Hinton DR. Hepatocyte growth factor protects RPE cells from apoptosis induced by glutathione depletion. Invest Ophthalmol Vis Sci 2005; 46:4311-9. [PMID: 16249513 DOI: 10.1167/iovs.05-0353] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To study the mechanism of the protective effect of hepatocyte growth factor (HGF) in oxidative injury to RPE cells induced by glutathione (GSH) depletion. METHODS RPE cells were treated with HGF for 24 hours (20 ng/mL) and then were treated with DL-buthionine-(S,R)-sulfoximine (BSO) for an additional 24 hours. Cell death, apoptosis, and GSH levels were measured. Levels of intracellular reactive oxygen species (ROS) and their cellular localization were assessed by confocal microscopy. Expression of Bcl-2 and release of cytochrome c from mitochondria were quantified. The effect of BSO on caspase-3 activation and expression was determined. Gene expression of key enzymes of GSH metabolism by real-time PCR and regulation and translocation of the transcription factor NF-E2-related factor (Nrf2) by BSO were examined. RESULTS Treatment with BSO-induced apoptosis in RPE caused a significant decrease in intracellular GSH and in GSH/GSSG ratios. Marked increases in lipid peroxidase (LPO), ROS, and mitochondrial cytochrome c release and a decrease in Bcl-2 expression were observed. Elevated GSH/GSSG ratio (especially in mitochondria), decreased LPO and ROS, attenuation of apoptosis, and partial restoration of Bcl-2 expression were found in the HGF-pretreated cells. BSO activated caspase-3, and this effect was significantly blocked by HGF. Both HGF and BSO induced anti-oxidant gene expression. Nrf2 translocated to the nuclear region after treatment with BSO, whereas HGF did not induce such translocation. CONCLUSIONS The protective effect of HGF may be attributed in part to the elevation of mitochondrial GSH. BSO and HGF act in concert to enhance GSH-related gene expression in stressed RPE cells.
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Affiliation(s)
- Manlin Jin
- Arnold and Mabel Beckman Macular Research Center, Los Angeles, California, USA
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Affiliation(s)
- Stephen J Ryan
- Doheny Eye Institute and Ophthalmology at the Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
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Lim JI, Spee C, Hangai M, Rocha J, Ying HS, Ryan SJ, Hinton DR. Neuropilin-1 expression by endothelial cells and retinal pigment epithelial cells in choroidal neovascular membranes. Am J Ophthalmol 2005; 140:1044-1050. [PMID: 16376649 DOI: 10.1016/j.ajo.2005.07.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Revised: 06/30/2005] [Accepted: 07/01/2005] [Indexed: 01/13/2023]
Abstract
PURPOSE To determine if vascular endothelial growth factor (VEGF) coreceptor neuropilin-1 (NP-1) is expressed in choroidal neovascularization (CNV) and to localize the expression. DESIGN Laboratory investigation. METHODS Six CNV membranes (CNVMs) obtained from patients with subfoveal CNV attributable to age-related macular degeneration (AMD) underwent immunohistochemistry for VEGF receptor-2 (VEGFR-2) and NP-1. The positive cell types were identified by double staining with anticytokeratin, anti-CD31, and antismooth muscle actin (SMA). RESULTS Immunohistochemical staining revealed positivity for VEGFR-2 and NP-1 in all six CNVMs. Both receptors were strongly expressed by new choroidal endothelial cell forming vessels and CD-31-positive cells in the nonvascular area. They were also expressed in the pigmented retinal pigment epithelial layer and by cytokeratin-positive, nonpigmented retinal pigment epithelium cells in the nonvascular area. The nonpigmented retinal pigment epithelium cells positive for VEGFR-2 and NP-1 were highly colocalized with SMA. CONCLUSIONS The presence of both VEGF and NP-1 suggest that NP-1 may play a role in the evolution of CNV in AMD.
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Affiliation(s)
- Jennifer I Lim
- Doheny Retina Institute of the Doheny Eye Institute and Department of Ophthalmology, University of Southern California Keck School of Medicine, 1450 San Pablo Street, Los Angeles, CA 90033, USA.
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Ryan SJ. National and International Patient Networks: Standardization of Phenotype and Genotype Definitions. Retina 2005; 25:S68. [PMID: 16374345 DOI: 10.1097/00006982-200512001-00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Stephen J Ryan
- Doheny Eye Institute and Ophthalmology at The Keck School of Medicine of the University of Southern California, Los Angeles, CA
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He S, Ding Y, Zhou J, Krasnoperov V, Zozulya S, Kumar SR, Ryan SJ, Gill PS, Hinton DR. Soluble EphB4 Regulates Choroidal Endothelial Cell Function and Inhibits Laser-Induced Choroidal Neovascularization. ACTA ACUST UNITED AC 2005; 46:4772-9. [PMID: 16303978 DOI: 10.1167/iovs.05-0502] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE The purpose of this study was to evaluate the effect of a soluble monomeric form of the EphB4 extracellular domain (sEphB4) on choroidal endothelial cell (CEC) migration and tube formation and on experimental laser-induced choroidal neovascularization (CNV). METHODS EphrinB2 and EphB4 expression in CECs was investigated by Western blot analysis and immunohistochemistry. Effects of sEphB4 (0.5-3 microg/mL) on CEC migration were evaluated with a modified Boyden chamber assay. Tube formation was assayed in CEC cultures in collagen gel. CNV was induced in rats by laser photocoagulation. The effects of intravitreal injection of sEphB4 on CNV development were evaluated at day 14 by fluorescein angiography (FA), confocal volumetric analysis of isolectin-B4 labeled flatmounts, and histologic examination of CNV membranes. RESULTS CEC cells express both EphB4 and EphrinB2, according to Western blot analysis. Immunohistochemical sections of rat eye showed immunoreactivity for both EphB4 and EphrinB2 in the choroidal endothelium. sEphB4 reduced CEC migration in response to vascular endothelial growth factor (P < 0.01). Similarly, sEphB4 inhibited CEC tube formation in a dose-dependent manner. EphB4, and to a lesser extent EphrinB2, were detected on vascular channels within laser-induced CNV membranes. Intravitreal injection of sEphB4 inhibited laser-induced CNV formation. CNV membranes showed a reduction in leakage score (P < 0.05), and membrane volumes were reduced in size (P < 0.05). Histologic analysis revealed that vascularity was reduced in sEphB4-treated membranes. CONCLUSIONS Recombinant soluble monomeric EphB4 exerts an inhibitory effect on choroidal angiogenesis in vitro and in vivo. It should be further evaluated for its potential as a novel therapy for CNV.
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Affiliation(s)
- Shikun He
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, USA
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Hangai M, He S, Hoffmann S, Lim JI, Ryan SJ, Hinton DR. Sequential induction of angiogenic growth factors by TNF-alpha in choroidal endothelial cells. J Neuroimmunol 2005; 171:45-56. [PMID: 16288810 DOI: 10.1016/j.jneuroim.2005.09.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Revised: 09/17/2005] [Accepted: 09/19/2005] [Indexed: 11/15/2022]
Abstract
Inflammatory mediators have been proposed to play a critical role in the pathogenesis of choroidal neovascularization, a blinding complication of age-related macular degeneration. We evaluated the expression of TNF-alpha in human choroidal neovascular membranes and found that it colocalized with cells expressing VEGF, angiopoietin (Ang)-1 and Ang2. In cultured choroidal endothelial cells we found that TNF-alpha increased Ang2 mRNA (increased transcription) and protein levels prior to those of Ang1 and VEGF. The results raise the possibility that during neovascularization, TNF-alpha may modulate endothelial plasticity and survival by sequential inactivation of Tie2 followed by activation of Tie2 and VEGF receptors.
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Affiliation(s)
- Masanori Hangai
- Department of Ophthalmology, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
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Redfern JV, Ryan SJ, Getz WM. Defining herbivore assemblages in the Kruger National Park: a correlative coherence approach. Oecologia 2005; 146:632-40. [PMID: 16217679 DOI: 10.1007/s00442-005-0235-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Accepted: 08/10/2005] [Indexed: 10/25/2022]
Abstract
Spatial associations of seven herbivore species in the Kruger National Park, South Africa, are analyzed using a new technique, Correlative Coherence Analysis (CoCA). CoCA is a generalization of the concept of correlation to more than two sequences of numbers. Prior information on the feeding ecology and metabolic requirements of these species is used to contrast spatial scales at which hypothesized guild aggregation or competition occurs. These hypotheses are tested using 13 years of aerial census data collected during the dry season. Our results are consistent with the hypothesis that distributions of large and small species of the same feeding type (i.e., grazers and browsers) overlap in potentially resource-rich areas, but have lower similarity values across all areas because the higher tolerance of large species for low quality foods results in a more even spatial distribution of large species compared to small species.
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Affiliation(s)
- J V Redfern
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA.
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Sreekumar PG, Kannan R, Yaung J, Spee CK, Ryan SJ, Hinton DR. Protection from oxidative stress by methionine sulfoxide reductases in RPE cells. Biochem Biophys Res Commun 2005; 334:245-53. [PMID: 15993845 DOI: 10.1016/j.bbrc.2005.06.081] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Accepted: 06/15/2005] [Indexed: 01/30/2023]
Abstract
We investigated the role of methionine sulfoxide reductases (Msrs) in oxidant-stress-induced cell death in retinal pigmented epithelial (RPE) cells. In RPE cells exposed to varying doses of H(2)O(2), gene expression of MsrA and hCBS-1 (the human analog of MsrB2) increased in a dose-dependent and time-dependent manner with maximal increase with 150 microM H(2)O(2) in 24h. H(2)O(2) treatment resulted in the generation of reactive oxygen species and activation of caspase 3. Confocal microscopic and protein analysis showed an increase in MsrA expression in cytosol and mitochondria. Silencing of MsrA resulted in caspase 3 induction and accentuated cell death from H(2)O(2). Focal, strong immunoreactivity for MsrA was observed in sub-RPE macular drusen from patients with age-related macular degeneration. In summary, our data show that MsrA and hCBS-1 are up-regulated in oxidative stress to counteract injury to RPE.
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Affiliation(s)
- Parameswaran G Sreekumar
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA 90033, USA
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Hoffmann S, Balthasar S, Friedrichs U, Ehren M, Ryan SJ, Wiedemann P. Inhibitory effects of verapamil isomers on the proliferation of choroidal endothelial cells. Graefes Arch Clin Exp Ophthalmol 2005; 244:376-81. [PMID: 16088412 DOI: 10.1007/s00417-004-1104-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 10/20/2004] [Accepted: 12/08/2004] [Indexed: 12/01/2022] Open
Abstract
PURPOSE To evaluate the effects of verapamil isomers on in vitro proliferation of bovine choroidal endothelial cells (CECs). MATERIALS AND METHODS CECs were isolated from bovine eyes and cultured in endothelial growth medium (EGM). For the proliferation assays, CECs were exposed to verapamil isomers (0.1-100 microM) in EGM with 2% fetal bovine serum or basic fibroblast growth factor (bFGF) (10 ng/ml). After 72 h of incubation with the desired drug, the cellular proliferation was determined by an MTT assay and a BrdU assay. In addition, the drug toxicity on CECs stimulated with EGM was evaluated by cell counting with trypan blue. RESULTS All verapamil isomers inhibited the bFGF- or medium-stimulated growth significantly in a concentration range of 10-40 microM without toxicity. No significant differences were seen between the inhibitory effects of the various isomers. Cell toxicity was detected at a concentration of 100 microM verapamil isomers on EGM-stimulated CECs. CONCLUSION The results demonstrate the efficacy of all verapamil isomers in inhibiting CEC proliferation involved in the process of choroidal neovascularization. D: -(+)-Verapamil may be recommended for further in vivo evaluation in an animal model of exudative AMD; it has fewer systemic and local side effects because calcium channels are not blocked.
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Affiliation(s)
- Stephan Hoffmann
- Department of Ophthalmology, University of Leipzig, Liebigstrasse 10-14, 04103, Leipzig, Germany.
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Hoffmann S, He S, Jin M, Ehren M, Wiedemann P, Ryan SJ, Hinton DR. A selective cyclic integrin antagonist blocks the integrin receptors alphavbeta3 and alphavbeta5 and inhibits retinal pigment epithelium cell attachment, migration and invasion. BMC Ophthalmol 2005; 5:16. [PMID: 15987521 PMCID: PMC1184086 DOI: 10.1186/1471-2415-5-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 06/29/2005] [Indexed: 01/21/2023] Open
Abstract
Background Proliferative vitreoretinopathy (PVR) is a leading cause of blindness after failed retinal reattachment surgery. PVR is characterized by the proliferation, migration and contraction of retinal pigmented epithelial cells (RPE), and these cellular responses are influenced by the expression and function of integrin receptors. The effect of a cyclic integrin antagonist containing the amino acid sequence Arg-Gly-Asp-D-Phe-Val (RGDfV), specific for the integrin receptors αvβ3 and αvβ5, was investigated on basic fibroblast growth factor (bFGF), platelet derived growth factor-BB (PDGF-BB), and serum induced human RPE proliferation, migration, invasion and attachment to the extracellular matrix. Furthermore, the effects of bFGF and PDGF-BB regulated expression of integrins αvβ3 and αvβ5 on RPE cells was examined. Methods The effect of a cyclic integrin antagonist and a control peptide (0.01 μg/ml to 300 μg/ml) was investigated on serum or cytokine (bFGF or PDGF-BB pretreatment) induced human fetal RPE cell proliferation by H3-thymidine uptake. The effect of the cyclic integrin antagonist on RPE cell attachment onto different extracellular matrices (laminin, collagen IV, fibronectin), RPE cell invasion stimulated by PDGF-BB or serum, and migration stimulated by PDGF-BB, vascular endothelial growth factor (VEGF) or serum was explored. PDGF-BB and bFGF modulation of the integrin receptors αvβ3 and αvβ5 was evaluated by flow cytometry. Results The integrin antagonist did not inhibit DNA synthesis stimulated by serum, bFGF, or PDGF-BB treatment. RPE attachment onto fibronectin was inhibited in a concentration range of 1–10 μg/ml (p < 0.05). Attachment of the RPE cells onto collagen IV and laminin was inhibited in a range of 3–10 μg/ml (p < 0.05). Serum and PDGF-BB stimulated migration was inhibited by the cyclic integrin antagonist in a concentration range of 1–10 μg/ml (p < 0.05). Furthermore, the cyclic integrin antagonist inhibited PDGF-BB stimulated RPE cell invasion through fibronectin (3μg/ml: 66% inhibition, p < 0.001). In each of these experiments, the control peptides had no significant effects. PDGF-BB and bFGF pretreatment of RPE cells increased the expression of integrin receptors αvβ3 (bFGF: 1.9 fold, PDGF-BB: 2.3 fold) and αvβ5 (bFGF: 2.9 fold, PDGF-BB: 1.5 fold). Conclusion A selective inhibition of the integrin receptors αvβ3 and αvβ5 through a cyclic integrin antagonist is able to inhibit RPE cell attachment, migration and invasion. Since these steps are of importance for the progression of PVR, a cyclic integrin antagonist should be further evaluated for the treatment of this disease.
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Affiliation(s)
- Stephan Hoffmann
- Doheny Eye Institute, Departments of Ophthalmology, Keck School of Medicine, University of Southern California 1355 San Pablo Street, Los Angeles 90033, CA, USA
- Department of Ophthalmology, University of Leipzig, Liebigstrasse 10–14, 04103 Leipzig, Germany
| | - Shikun He
- Doheny Eye Institute, Departments of Ophthalmology, Keck School of Medicine, University of Southern California 1355 San Pablo Street, Los Angeles 90033, CA, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, 2011 Zonal Ave HMR 209, Los Angeles, CA 90033, USA
| | - Manlin Jin
- Department of Pathology, Keck School of Medicine, University of Southern California, 2011 Zonal Ave HMR 209, Los Angeles, CA 90033, USA
| | - Marianne Ehren
- Berufsgenossenschaftliche Kliniken Bergmannsheil, University of Bochum, Department of Internal Medicine I, Bürkle-de-la-Camp-Platz 1, D-44789 Bochum, Germany
| | - Peter Wiedemann
- Department of Ophthalmology, University of Leipzig, Liebigstrasse 10–14, 04103 Leipzig, Germany
| | - Stephen J Ryan
- Doheny Eye Institute, Departments of Ophthalmology, Keck School of Medicine, University of Southern California 1355 San Pablo Street, Los Angeles 90033, CA, USA
| | - David R Hinton
- Doheny Eye Institute, Departments of Ophthalmology, Keck School of Medicine, University of Southern California 1355 San Pablo Street, Los Angeles 90033, CA, USA
- Department of Pathology, Keck School of Medicine, University of Southern California, 2011 Zonal Ave HMR 209, Los Angeles, CA 90033, USA
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Zhou J, Pham L, Zhang N, He S, Gamulescu MA, Spee C, Ryan SJ, Hinton DR. Neutrophils promote experimental choroidal neovascularization. Mol Vis 2005; 11:414-24. [PMID: 15988410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
PURPOSE To investigate the role of neutrophils in the development of laser induced experimental choroidal neovascularization (CNV). METHODS CNV was induced by laser photocoagulation in adult male C57BL/6J mice. Neutrophil infiltration was evaluated by histology and confocal immunohistology. The expression of neutrophil chemotactic chemokines in the regions of laser injury was determined by quantitative real-time PCR. Animals were treated with NIMP-R14, an anti-murine neutrophil monoclonal antibody (mAb), intraperitoneally to deplete neutrophils. The specific neutrophil depletion was confirmed by flow cytometry. The CNV responses were compared between neutropenic and untreated control mice on the basis of fluorescein angiography (FA), CNV lesion volume and lesion histology, and vascular endothelial growth factor (VEGF) expression by ELISA. Expression of VEGF and Angiopoietin-1 and Angiopoietin-2 protein by murine neutrophils was evaluated by confocal immunohistochemistry. RESULTS Neutrophils infiltrated the sites of laser injury as early as day 1 after laser treatment and peaked at day 3. The neutrophil infiltration correlated with enhanced mRNA expression of neutrophil chemotactic chemokines MIP-2 and KC in the lesions. Administration of NIMP-R14 mAb specifically depleted neutrophils. Analysis of FA, CNV volume, and lesion histology, all demonstrated a moderate decrease in the CNV response in neutropenic mice compared to control mice (p<0.01). The reduction in the CNV response in neutropenic mice was associated with decreased VEGF protein levels in the ocular posterior segment. Murine neutrophils contained VEGF and Angiopoietin-1 and Angiopoietin-2 proteins. CONCLUSIONS Neutrophil invasion was part of early inflammatory responses during laser induced CNV. Neutrophil depletion correlated with reduced CNV responses and decreased VEGF protein expression. These data suggest that neutrophils promoted the early development of CNV possibly via secretion of angiogenic growth factors.
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Affiliation(s)
- Jiehao Zhou
- The Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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