Notch2 regulates BMP signaling and epithelial morphogenesis in the ciliary body of the mouse eye.

The ciliary body (CB) of the mammalian eye is responsible for secreting aqueous humor to maintain intraocular pressure, which is elevated in the eyes of glaucoma patients. It contains a folded two-layered epithelial structure comprising the nonpigmented inner ciliary epithelium (ICE), the pigmented outer ciliary epithelium (OCE), and the underlying stroma. Although the CB has an important function in the eye, its morphogenesis remains poorly studied. In this study, we show that conditional inactivation of the Jagged 1 (Jag1)-Notch2 signaling pathway in the developing CB abolishes its morphogenesis. Notch2 is expressed in the OCE of the CB, whereas Jag1 is expressed in the ICE. Conditional inactivation of Jag1 in the ICE or Notch2 in the OCE disrupts CB morphogenesis, but neither affects the specification of the CB region. Notch2 signaling in the OCE is required for promoting cell proliferation and maintaining bone morphogenetic protein (BMP) signaling, both of which have been suggested to be important for CB morphogenesis. Although Notch and BMP signaling pathways are known to cross-talk via the interaction between their downstream transcriptional factors, this study suggests that Notch2 maintains BMP signaling in the OCE possibly by repressing expression of secreted BMP inhibitors. Based on our findings, we propose that Jag1-Notch2 signaling controls CB morphogenesis at least in part by regulating cell proliferation and BMP signaling.

NOTCH Signaling Controls Ciliary Body Morphogenesis and Secretion by Directly Regulating Nectin Protein Expression.

Anterior segment dysgenesis is often associated with cornea diseases, cataracts, and glaucoma. In the anterior segment, the ciliary body (CB) containing inner and outer ciliary epithelia (ICE and OCE) secretes aqueous humor that maintains intraocular pressure (IOP). However, CB development and function remain poorly understood. Here, this study shows that NOTCH signaling in the CB maintains the vitreous, IOP, and eye structures by regulating CB morphogenesis, aqueous humor secretion, and vitreous protein expression. Notch2 and Notch3 function via RBPJ in the CB to control ICE-OCE adhesion, CB morphogenesis, aqueous humor secretion, and protein expression, thus maintaining IOP and eye structures. Mechanistically, NOTCH signaling transcriptionally controls Nectin1 expression in the OCE to promote cell adhesion for driving CB morphogenesis and to directly stabilize Cx43 for controlling aqueous humor secretion. Finally, NOTCH signaling directly controls vitreous protein secretion in the ICE. Therefore, this study provides important insight into CB functions and involvement in eye diseases.

The relevance of living supports on antiplatelet adherence and trial participation: the SPS3 trial.

BACKGROUND: While living with others has been associated with improved functional outcome after acute stroke, it is unclear if this affects adherence to stroke prevention measures. AIMS: We examined the relationship between living arrangements and adherence to antiplatelet therapy assignment and participation status in an international randomized trial for secondary stroke prevention. METHOD: Antiplatelet therapy adherence, trial retention outcomes, and baseline characteristics for participants enrolled in the Secondary Prevention of Small Subcortical Strokes study were compared between those who lived alone vs. with others (n = 2374). Participant status at end-of-trial was categorized into (1) on assigned antiplatelet, (2) off assigned antiplatelet by participant request, or (3) participant withdrew consent/lost to follow-up. Multivariable multivariate logistic regression was used to identify patient features at entry predictive of participant status at trial end. RESULTS: Living arrangement, alone vs. with other(s), was not significantly associated with participant status. Participants enrolled in the United States/Canada (odds ratio 3.1, confidence intervals 2.0-5.0, vs. Latin America), taking more (7+) prescription medications (odds ratio 1.7, confidence intervals 1.1-2.7, vs. 0-2 medications), and scoring lower on the Stroke Specific Quality of Life scale (odds ratio 1.3, confidence intervals 1.1-1.5, per 10 points) were more likely to withdraw or become lost to follow-up in the study vs. completing the study on assigned antiplatelet therapy. Participants enrolled in the United States/Canada (odds ratio 5.0, confidence intervals 2.4-10.0, vs. Latin America) and taking fewer (0-2) medications (odds ratio 1.9, confidence intervals 1.2-3.1 vs. 3-6 medications) were more likely to request discontinuation of assigned antiplatelet medication vs. completing the study. CONCLUSION: Living with others was not independently predictive of protocol adherence in this cohort. Number of medications and Stroke Specific Quality of Life scale score may be more indicative of likelihood of trial participation and acceptance of long-term antiplatelet regimen.

Cadherin-mediated cell adhesion is critical for the closing of the mouse optic fissure.

Coloboma is a congenital disease that contributes significantly to childhood blindness. It results from the failure in closing the optic fissure, a transient opening on the ventral side of the developing eye. Although human and mouse genetic studies have identified a number of genes associated with coloboma, the detailed cellular mechanisms underlying the optic fissure closure and coloboma formation remain largely undefined. N-cadherin-mediated cell adhesion has been shown to be important for the optic fissure closure in zebrafish, but it remains to be determined experimentally how cell-cell adhesions are involved in the mammalian optic fissure closing process. α-Catenin is required for cell adhesion mediated by all of the classic cadherin molecules, including N-cadherin. In this study, we used the Cre-mediated conditional knockout technique to specifically delete α-catenin from the developing mouse eye to show that it is required for the successful closing of the optic fissure. In α-catenin conditional mutant optic cups, the major cell fates, including the optic fissure margin, neural retina and retinal pigmented epithelium, are specified normally, and the retinal progenitor cells proliferate normally. However, adherens junctions components, including N-cadherin, ß-catenin and filamentous actin, fail to accumulate on the apical side of α-catenin mutant retinal progenitor cells, where adherens junctions are normally abundant, and the organization of the neural retina and the optic fissure margin is disrupted. Finally, the α-catenin mutant retina gradually degenerates in the adult mouse eye. Therefore, our results show that α-catenin-mediated cell adhesion and cell organization are important for the fissure closure in mice, and further suggest that genes that regulate cell adhesion may underlie certain coloboma cases in humans.