Abstract
Purpose :
Glaucoma is a multifactorial disease leading to irreversible blindness. Glaucoma is associated with elevation of intraocular pressure (IOP) due to damage to the trabecular meshwork (TM). Transforming growth factor (TGF)β2 is known to cause TM damage and elevate IOP. Mouse models of TGFβ2-induced IOP elevation help understand the underlying molecular mechanism of the disease progression. The goal of this study was to develop a mouse model of IOP elevation using lentiviral gene transfer of active TGFβ2.
Methods :
Lentiviral vector constructs encoding active hTGFβ2(C226,228S) with CMV or CBh promoter were purchased from VectorBuilder. Empty lentivirus vector (LV-CMV-Null-Puro) obtained from SignaGen Labs was used as control. C57BL/6J and BALB/cJ mouse strains, age group of >4 months old, were used for the study. The ultra-pure lentiviral particles expressing TGFβ2 or null were intravitreally injected (2x106 TU/eyes) into contralateral eyes of each anesthetized mice. IOP was weekly monitored followed by assessment of aqueous outflow facility. TGFβ2 expression was assessed in aqueous humor (AH) and anterior segments of injected eyes. Hematoxylin and eosin staining was performed to examine the morphology of mouse eyes. Effect on RGC function and cell count was determined via pattern ERG (pERG) and RBPMS staining, respectively.
Results :
Eyes injected with lenti-CMV-TGFβ2 viral particles significantly increased IOP post 3-weeks of injection compared to the control eyes. The average IOP elevation observed was 3.3 mmHg and stayed consistent up to 7-week post injection. Individual mice assessment revealed 50% response rate to lenti-TGFβ2-induced IOP elevation with average delta change of 6.19 mmHg among the responders. Likewise, the responder mice showed 64.05% drop in AH outflow facility. Nevertheless, no cellular or functional loss of RGC was observed even among the responders. Increased expression of active TGFβ2 was observed in both AH and anterior segment samples of injected mice compared to null injected mice. Mild development of lenticular opacity was detected in some TGFβ2-injected eyes, however, there were no visible signs of inflammation noticed in any of the injected eyes.
Conclusions :
Sustained increase in IOP with consequent decrease in outflow facility was effectively demonstrated via lentiviral gene delivery of active TGFβ2 under control of CMV promoter.
This is a 2021 ARVO Annual Meeting abstract.