Ms. Gabelt is a Distinguished Scientist in the Department of Ophthalmology and Visual Sciences at the University of Wisconsin School of Medicine and Public Health. She has 29 years of experience conducting ocular physiology studies related to glaucoma pharmacotherapy and anterior segment gene therapy in nonhuman primates. These include intraocular pressure, aqueous humor formation, outflow facility and uveoscleral outflow. She has also developed anterior segment organ-culture systems for pig, monkey, and cow which can be used to measure effects on trabecular outflow.
SB772077B, A New Rho Kinase Inhibitor Enhances Aqueous Humour Outflow Facility in Human Eyes.
Sci Rep. 2018 Oct 19;8(1):15472
Authors: Ashwinbalaji S, Senthilkumari S, Gowripriya C, Krishnadas S, Gabelt BAT, Kaufman PL, Muthukkaruppan V
We investigated the effect of a new Rho kinase inhibitor, SB772077B (SB77) on aqueous outflow facility (OF) in human eyes using human organ-cultured anterior segment (HOCAS). IOP was monitored for 24 h post-treatment with either SB77 (0.1/10/50 µM) or vehicle after a stable baseline pressure. The hydrodynamic pattern of aqueous outflow was analysed by labelling outflow pathway with red fluorescent microspheres. The effect of SB77 on cell morphology, actin stress fibers, focal adhesions, ECM, status of RhoA activation and myosin light chain phosphorylation (p-MLC) were evaluated and compared with Y27632, by immunostaining using primary human trabecular meshwork (HTM) cells. Following 24 h treatment, SB77 increased OF by 16% at 0.1 µM (N = 6), 29% at 10 µM (N = 8; p = 0.018) and 39% at 50 µM (N = 8; p = 0.004) in human eyes. There was an overall increase in tracer quantity and in area along inner wall of Schlemm's canal. Treatment with SB77 showed no evidence of cytotoxicity and caused a significant reduction in the expression of fibrotic markers compared to Y27632. The present findings indicate that SB77 treatment was effective in enhancing OF and reducing fibrotic markers in an ex vivo model. Thus SB77 may be a potential clinical candidate for the management of glaucoma.
PMID: 30341380 [PubMed - in process]
Viral Vector Effects on Exoenzyme C3 Transferase Mediated Actin Disruption and on Outflow Facility.
Invest Ophthalmol Vis Sci. 2015 Mar 17;
Authors: Slauson SR, Peters DM, Schwinn MK, Kaufman PL, Gabelt BT, Brandt CR
PURPOSE: Purified C. botulinum exoenzyme C3 transferase (C3) effects on the actin cytoskeleton in human trabecular meshwork cells (HTM) and on the outflow facility response in monkey organ-cultured anterior segments (MOCAS) were determined in the presence or absence of viral vectors.
METHODS: Human adenovirus type 5 (AdV) and feline immunodeficiency virus (FIV) were produced using kits. Cell soluble purified C3 (C3cs) was purchased commercially. Recombinant C3 (C3rec) cDNA was overexpressed in E. coli and purified. HTM cells were incubated with up to 10µg/ml C3cs or with 5 μg of C3rec and/or viral vector (MOI=25). Cells were then fixed and stained for actin. Outflow facility in MOCAS was measured at baseline, 4 hrs, 24 hrs, and 3-4 days following bolus injection of AdV (1.6x10e7 transducing units) and/or 2.5µg C3rec.
RESULTS: HTM cells treated for 4hrs with C3cs (all doses) or for 24hrs with C3rec developed a rounded morphology and lost stress fibers. Cells transduced with vectors alone showed no changes at any time-point. Cells exposed to C3rec and co-transduced with either viral vector showed significant disruption of the actin cytoskeleton within 4 hrs post-exposure, which persisted at 24 hrs. In MOCAS, the AdV vector alone had no effect on outflow facility but enhanced the response to C3rec at 4 hours.
CONCLUSIONS: Co-administration of viral vectors enhances the ability of C3 transferase to disrupt actin stress fiber formation in HTM cells and increase outflow facility in MOCAS. Viral vectors could potentially be utilized to increase the bioavailability of proteins for cells that are difficult to transfect.
PMID: 25783606 [PubMed - as supplied by publisher]
Prospects for lentiviral vector mediated prostaglandin F synthase gene delivery in monkey eyes in vivo.
Curr Eye Res. 2014 Sep;39(9):859-70
Authors: Lee ES, Rasmussen CA, Filla MS, Slauson SR, Kolb AW, Peters DM, Kaufman PL, Gabelt BT, Brandt CR
Currently, the most effective outflow drugs approved for clinical use are prostaglandin F2α analogues, but these require daily topical self-dosing and have various intraocular, ocular surface and extraocular side effects. Lentiviral vector-mediated delivery of the prostaglandin F synthase (PGFS) gene, resulting in long-term reduction of intraocular pressure (IOP), may eliminate off-target tissue effects and the need for daily topical PGF2α self-administration. Lentiviral vector-mediated delivery of the PGFS gene to the anterior segment has been achieved in cats and non-human primates. Although these results are encouraging, our studies have identified a number of challenges that need to be overcome for prostaglandin gene therapy to be translated into the clinic. Using examples from our work in non-human primates, where we were able to achieve a significant reduction in IOP (2 mm Hg) for 5 months after delivery of the cDNA for bovine PGF synthase, we identify and discuss these issues and consider several possible solutions.
PMID: 24559478 [PubMed - indexed for MEDLINE]