The relationship between Graves’ ophthalmopathy and dry eye syndrome

Jessica H Selter,1 Anisa I Gire,2 Shameema Sikder2 1Johns Hopkins School of Medicine, 2Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA Background: A complex relationship between Graves’ ophthalmopathy (GO) and dry eye syndrome exists. New research brings more insight into the association between these two diseases.Methods: A review of the literature was conducted using the query terms “Graves’ Ophthalmopathy”, “Thyroid Eye Disease”, and “Dry Eye” in MedLine (PubMed) and Scopus. A total of 55 papers were reviewed. Case reports were excluded.Conclusion: This review paper shows the close relationship between dry eye syndrome and GO. The underlying mechanisms behind their association suggest mechanical impairment of orbital muscles and immune-mediated lacrimal gland dysfunction as the causes of dry eye in GO patients. However, there are a variety of treatment options available for patients with GO with signs of dry eye, which help combat this issue. Keywords: Graves’ ophthalmopathy, dry eye, thyroid eye disease, ocular inflammatio

Mutations in the DNA-binding domain of NR2E3 affect in vivo dimerization and interaction with CRX.

BACKGROUND: NR2E3 (PNR) is an orphan nuclear receptor essential for proper photoreceptor determination and differentiation. In humans, mutations in NR2E3 have been associated with the recessively inherited enhanced short wavelength sensitive (S-) cone syndrome (ESCS) and, more recently, with autosomal dominant retinitis pigmentosa (adRP). NR2E3 acts as a suppressor of the cone generation program in late mitotic retinal progenitor cells. In adult rod photoreceptors, NR2E3 represses cone-specific gene expression and acts in concert with the transcription factors CRX and NRL to activate rod-specific genes. NR2E3 and CRX have been shown to physically interact in vitro through their respective DNA-binding domains (DBD). The DBD also contributes to homo- and heterodimerization of nuclear receptors. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed NR2E3 homodimerization and NR2E3/CRX complex formation in an in vivo situation by Bioluminescence Resonance Energy Transfer (BRET(2)). NR2E3 wild-type protein formed homodimers in transiently transfected HEK293T cells. NR2E3 homodimerization was impaired in presence of disease-causing mutations in the DBD, except for the p.R76Q and p.R104W mutant proteins. Strikingly, the adRP-linked p.G56R mutant protein interacted with CRX with a similar efficiency to that of NR2E3 wild-type and p.R311Q proteins. In contrast, all other NR2E3 DBD-mutant proteins did not interact with CRX. The p.G56R mutant protein was also more effective in abolishing the potentiation of rhodospin gene transactivation by the NR2E3 wild-type protein. In addition, the p.G56R mutant enhanced the transrepression of the M- and S-opsin promoter, while all other NR2E3 DBD-mutants did not. CONCLUSIONS/SIGNIFICANCE: These results suggest different disease mechanisms in adRP- and ESCS-patients carrying NR2E3 mutations. Titration of CRX by the p.G56R mutant protein acting as a repressor in trans may account for the severe clinical phenotype in adRP patients