Browsing by Author "Clark, Abbot F."

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    The Canonical Wnt Signaling Pathway Inhibits the Glucocorticoid Receptor Signaling Pathway in the Trabecular Meshwork
    (Elsevier, 2021) Sugali, Chenna Kesavulu; Rayana, Naga Pradeep; Dai, Jiannong; Peng, Michael; Harris, Sherri L.; Webber, Hannah C.; Liu, Shaohui; Dixon, Stephan G.; Parekh, Priyanka H.; Martin, Elizabeth A.; Cantor, Louis B.; Fellman, Ronald L.; Godfrey, David G.; Butler, Michelle R.; Emanuel, Matthew E.; Grover, Davinder S.; Smith, Oluwatosin U.; Clark, Abbot F.; Raghunathan, Vijay Krishna; Mao, Weiming; Ophthalmology, School of Medicine
    Glucocorticoid-induced glaucoma is a secondary open-angle glaucoma. About 40% of the general population may develop elevated intraocular pressure on prolonged glucocorticoid treatment secondary to damages in the trabecular meshwork (TM), a tissue that regulates intraocular pressure. Therefore, identifying the key molecules responsible for glucocorticoid-induced ocular hypertension is crucial. In this study, Dickkopf-related protein 1 (Dkk1), a canonical Wnt signaling inhibitor, was found to be elevated in the aqueous humor and TM of glaucoma patients. At the signaling level, Dkk1 enhanced glucocorticoid receptor (GR) signaling, whereas Dkk1 knockdown or Wnt signaling activators decreased GR signaling in human TM cells as indicated by luciferase assays. Similarly, activation of the GR signaling inhibited Wnt signaling. At the protein level, glucocorticoid-induced extracellular matrix was inhibited by Wnt activation using Wnt activators or Dkk1 knockdown in primary human TM cells. In contrast, inhibition of canonical Wnt signaling by β-catenin knockdown increased glucocorticoid-induced extracellular matrix proteins. At the physiological level, adenovirus-mediated Wnt3a expression decreased glucocorticoid-induced ocular hypertension in mouse eyes. In summary, Wnt and GR signaling inhibit each other in the TM, and canonical Wnt signaling activators may prevent the adverse effect of glucocorticoids in the eye.
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    Consensus Recommendation for Mouse Models of Ocular Hypertension to Study Aqueous Humor Outflow and Its Mechanisms
    (Association for Research in Vision and Ophthalmology, 2022) McDowell, Colleen M.; Kizhatil, Krishnakumar; Elliott, Michael H.; Overby, Darryl R.; van Batenburg-Sherwood, Joseph; Millar, J. Cameron; Kuehn, Markus H.; Zode, Gulab; Acott, Ted S.; Anderson, Michael G.; Bhattacharya, Sanjoy K.; Bertrand, Jacques A.; Borras, Terete; Bovenkamp, Diane E.; Cheng, Lin; Danias, John; De Ieso, Michael Lucio; Du, Yiqin; Faralli, Jennifer A.; Fuchshofer, Rudolf; Ganapathy, Preethi S.; Gong, Haiyan; Herberg, Samuel; Hernandez, Humberto; Humphries, Peter; John, Simon W.M.; Kaufman, Paul L.; Keller, Kate E.; Kelley, Mary J.; Kelly, Ruth A.; Krizaj, David; Kumar, Ajay; Leonard, Brian C.; Lieberman, Raquel L.; Liton, Paloma; Liu, Yutao; Liu, Katy C.; Lopez, Navita N.; Mao, Weiming; Mavlyutov, Timur; McDonnell, Fiona; McLellan, Gillian J.; Mzyk, Philip; Nartey, Andrews; Pasquale, Louis R.; Patel, Gaurang C.; Pattabiraman, Padmanabhan P.; Peters, Donna M.; Raghunathan, Vijaykrishna; Rao, Ponugoti Vasantha; Rayana, Naga; Raychaudhuri, Urmimala; Reina-Torres, Ester; Ren, Ruiyi; Rhee, Douglas; Chowdhury, Uttio Roy; Samples, John R.; Samples, E. Griffen; Sharif, Najam; Schuman, Joel S.; Sheffield, Val C.; Stevenson, Cooper H.; Soundararajan, Avinash; Subramanian, Preeti; Sugali, Chenna Kesavulu; Sun, Yang; Toris, Carol B.; Torrejon, Karen Y.; Vahabikashi, Amir; Vranka, Janice A.; Wang, Ting; Willoughby, Colin E.; Xin, Chen; Yun, Hongmin; Zhang, Hao F.; Fautsch, Michael P.; Tamm, Ernst R.; Clark, Abbot F.; Ethier, C. Ross; Stamer, W. Daniel; Ophthalmology, School of Medicine
    Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings.
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    Consensus Recommendation for Mouse Models of Ocular Hypertension to Study Aqueous Humor Outflow and Its Mechanisms
    (ARVO, 2022-02) McDowell, Colleen M.; Kizhatil, Krishnakumar; Elliott, Michael H.; Overby, Darryl R.; Van Batenburg-Sherwood, Joseph; Millar, J. Cameron; Kuehn, Markus H.; Zode, Gulab; Acott, Ted S.; Anderson, Michael G.; Bhattacharya, Sanjoy K.; Bertrand, Jacques A.; Borras, Terete; Bovenkamp, Diane E.; Cheng, Lin; Danias, John; De Ieso, Michael Lucio; Du, Yiqin; Faralli, Jennifer A.; Fuchshofer, Rudolf; Ganapathy, Preethi S.; Gong, Haiyan; Herberg, Samuel; Hernandez, Humberto; Humphries, Peter; John, Simon W. M.; Kaufman, Paul L.; Keller, Kate E.; Kelley, Mary J.; Kelly, Ruth A.; Krizaj, David; Kumar, Ajay; Leonard, Brian C.; Lieberman, Raquel L.; Liton, Paloma; Liu, Yutao; Liu, Katy C.; Lopez, Navita N.; Mao, Weiming; Mavlyutov, Timur; McDonnell, Fiona; McLellan, Gillian J.; Mzyk, Philip; Nartey, Andrews; Pasquale, Louis R.; Patel, Gaurang C.; Pattabiraman, Padmanabhan P.; Peters, Donna M.; Raghunathan, Vijaykrishna; Rao, Ponugoti Vasantha; Rayana, Naga; Raychaudhuri, Urmimala; Reina-Torres, Ester; Ren, Ruiyi; Rhee, Douglas; Chowdhury, Uttio Roy; Samples, John R.; Samples, E. Griffen; Sharif, Najam; Schuman, Joel S.; Sheffield, Val C.; Stevenson, Cooper H.; Soundararajan, Avinash; Subramanian, Preeti; Sugali, Chenna Kesavulu; Sun, Yang; Toris, Carol B.; Torrejon, Karen Y.; Vahabikashi, Amir; Vranka, Janice A.; Wang, Ting; Willoughby, Colin E.; Xin, Chen; Yun, Hongmin; Zhang, Hao F.; Fautsch, Michael P.; Tamm, Ernst R.; Clark, Abbot F.; Ethier, C. Ross; Stamer, W. Daniel; Ophthalmology, School of Medicine
    Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings.
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    Consensus Recommendations for Studies of Outflow Facility and Intraocular Pressure Regulation Using Ex Vivo Perfusion Approaches
    (Association for Research in Vision and Ophthalmology, 2024) Acott, Ted S.; Fautsch, Michael P.; Mao, Weiming; Ethier, C. Ross; Huang, Alex S.; Kelley, Mary J.; Aga, Mini; Bhattacharya, Sanjoy K.; Borras, Terete; Bovenkamp, Diane; Chowdhury, Uttio Roy; Clark, Abbot F.; Dibas, Mohammed I.; Du, Yiqin; Elliott, Michael H.; Faralli, Jennifer A.; Gong, Haiyan; Herberg, Samuel; Johnstone, Murray A.; Kaufman, Paul L.; Keller, Kate E.; Kelly, Ruth A.; Krizaj, David; Kuehn, Markus H.; Li, Hoi Lam; Lieberman, Raquel; Lin, Shan C.; Liu, Yutao; McDonnell, Fiona S.; McDowell, Colleen M.; McLellan, Gillian J.; Mzyk, Philip; Nair, Kayarat Saidas; Overby, Darryl R.; Peters, Donna M.; Raghunathan, VijayKrishna; Rao, Ponugoti Vasantha; Roddy, Gavin W.; Sharif, Najam A.; Shim, Myoung Sup; Sun, Yang; Thomson, Benjamin R.; Toris, Carol B.; Willoughby, Colin E.; Zhang, Hao F.; Freddo, Thomas F.; Fuchshofer, Rudolf; Hill, Kamisha R.; Karimi, Alireza; Kizhatil, Krishnakumar; Kopcyznski, Casey C.; Liton, Paloma; Patel, Gaurang; Peng, Michael; Pattabiraman, Padmanabhan P.; Prasanna, Ganesh; Reina-Torres, Ester; Samples, E. Griffen; Samples, John R.; Steel, Cynthia L.; Strohmaier, Clemens A.; Subramanian, Preeti; Sugali, Chenna Kesavulu; van Batenburg-Sherwood, Joseph; Wong, Cydney; Youngblood, Hannah; Zode, Gulab S.; White, Elizabeth; Stamer, W. Daniel; Ophthalmology, School of Medicine
    Intraocular pressure (IOP) elevation is the primary risk factor and currently the main treatable factor for progression of glaucomatous optic neuropathy. In addition to direct clinical and living animal in vivo studies, ex vivo perfusion of anterior segments and whole eyes is a key technique for studying conventional outflow function as it is responsible for IOP regulation. We present well-tested experimental details, protocols, considerations, advantages, and limitations of several ex vivo model systems for studying IOP regulation. These include: (1) perfused whole globes, (2) stationary anterior segment organ culture, (3) perfused human anterior segment organ culture, (4) perfused animal anterior segment organ culture, (5) perfused human corneal rims, and (6) perfused human anterior segment wedges. These methods, with due consideration paid to their strengths and limitations, comprise a set of very strong tools for extending our understanding of IOP regulation.