Departmental Affiliation and City, State, Zip for All Authors

North Texas Eye Research Institute Fort Worth, TX 76107

Scientific Abstract

Purpose: Elevated intraocular pressure (IOP) is one of the main risk factors in the development of glaucoma. TGFβ2 is well known to be involved in regulating both the extracellular matrix in the trabecular meshwork (TM) as well as ocular hypertension. BAMBI (BMP and activin membrane-bound inhibitor) has been shown to be a negative regulator of TGF-β2. However, the role of BAMBI in regulating IOP is unknown. We investigated whether knockdown of BAMBI results in ocular hypertension in mice changes to the ECM in the TM due to uninhibited TGFβ2 signaling. Methods: B6;129S1-Bambitm1Jian/J mice were injected intravitreally with 2.5x107 pfu of either Ad5.TGFβ2 (n=10), Ad5.Cre (n=9), or Ad5.TGFβ2 + Ad5.Cre (n=10), in one eye of each animal. The contralateral uninjected eyes were used as negative controls. IOP was measured using a TonoLab rebound tonometer. BAMBI and Fibronectin expression was assessed in the TM by immunohistochemistry on cross-sections of eyes from Bambitm1Jian/J floxed mice and visualized by fluorescence microscopy. Results: Injection with either Ad5.Cre, Ad5.TGFβ2, or Ad5.TGFβ2 + Ad5.Cre each induced ocular hypertension starting at day 7 post-injection and maintained significant IOP elevation throughout the 56-day time course compared to uninjected control eyes (p<0.01, days 7-56). Ad5.Cre sufficiently knockdown BAMBI expression and increased Fibronectin expression in the TM compared to uninjected control eyes. Conclusion: We show for the first time that conditional knockdown of BAMBI with Ad5.Cre induces ocular hypertension and increases Fibronectin expression in the tm. These data further explain the molecular mechanisms involved in the development of glaucomatous TM damage and provide potential new targets to lower IOP.

Share

COinS
 

EFFECT OF BAMBI EXPRESSION ON THE ECM OF TRABECULAR MESHWORK AND INTRAOCULAR PRESSURE

Purpose: Elevated intraocular pressure (IOP) is one of the main risk factors in the development of glaucoma. TGFβ2 is well known to be involved in regulating both the extracellular matrix in the trabecular meshwork (TM) as well as ocular hypertension. BAMBI (BMP and activin membrane-bound inhibitor) has been shown to be a negative regulator of TGF-β2. However, the role of BAMBI in regulating IOP is unknown. We investigated whether knockdown of BAMBI results in ocular hypertension in mice changes to the ECM in the TM due to uninhibited TGFβ2 signaling. Methods: B6;129S1-Bambitm1Jian/J mice were injected intravitreally with 2.5x107 pfu of either Ad5.TGFβ2 (n=10), Ad5.Cre (n=9), or Ad5.TGFβ2 + Ad5.Cre (n=10), in one eye of each animal. The contralateral uninjected eyes were used as negative controls. IOP was measured using a TonoLab rebound tonometer. BAMBI and Fibronectin expression was assessed in the TM by immunohistochemistry on cross-sections of eyes from Bambitm1Jian/J floxed mice and visualized by fluorescence microscopy. Results: Injection with either Ad5.Cre, Ad5.TGFβ2, or Ad5.TGFβ2 + Ad5.Cre each induced ocular hypertension starting at day 7 post-injection and maintained significant IOP elevation throughout the 56-day time course compared to uninjected control eyes (p<0.01, days 7-56). Ad5.Cre sufficiently knockdown BAMBI expression and increased Fibronectin expression in the TM compared to uninjected control eyes. Conclusion: We show for the first time that conditional knockdown of BAMBI with Ad5.Cre induces ocular hypertension and increases Fibronectin expression in the tm. These data further explain the molecular mechanisms involved in the development of glaucomatous TM damage and provide potential new targets to lower IOP.

Manuscript Number

1014