Heterodimers of photoreceptor-specific nuclear receptor (PNR/NR2E3) and peroxisome proliferator-activated receptor (PPARγ) are disrupted by retinal disease-associated mutations

Photoreceptor-specific nuclear receptor (PNR/NR2E3) and Tailless homolog (TLX/NR2E1) are human orthologs of the NR2E group, a subgroup of phylogenetically related members of the Nuclear Receptor (NR) superfamily of transcription factors. We assessed the ability of these NRs to form heterodimers with other members of the human NRs representing all major subgroups. The TLX ligand binding domain (LBD) did not appear to form homodimers or interact directly with any other NR tested. The PNR LBD was able to form homodimers, but also exhibited robust interactions with the LBDs of PPARγ/NR1C3 and TRβ/NR1A2. The binding of PNR to PPARγ was specific for this paralog, as no interaction was observed with the LBDs of PPARαNR1C1 or PPARδNR1C2. In support of these findings, PPARγ and PNR were found to be co-expressed in human retinal tissue extracts and could be co-immunoprecipitated as a native complex. Selected sequence variants in the PNR LBD associated with human retinopathies, or a mutation in the dimerization region of PPARγ LBD associated with familial partial lipodystrophy type 3, were found to disrupt PNR/PPARγ complex formation. Wild type PNR, but not a PNR309G mutant, was able to repress PPARγ-mediated transcription in reporter assays. In summary our results reveal novel heterodimer interactions in the NR superfamily, suggesting previously unknown functional interactions of PNR with PPARγ and TRβ that have potential importance in retinal development and disease

The role of aflibercept in the management of diabetic macular edema

Andrew A Chang,1–3 Thomas Hong,1,2 Shaun Y Ewe,1,2 Bobak Bahrami,1,2 Geoffrey K Broadhead1–3 1Sydney Institute of Vision Science, 2Sydney Retina Clinic and Day Surgery, 3Save Sight Institute, University of Sydney, Sydney, NSW, Australia Abstract: Diabetic macular edema (DME) represents one of the leading causes of visual impairment in working-age adults. Although there are several proven treatments available for this condition, pharmacotherapy through the use of intravitreal antivascular endothelial growth factor agents has revolutionized the management of DME over the past decade with superior outcomes compared to laser therapy. This review summarizes the pathophysiology and available treatment options for the management of DME, with an emphasis on the efficacy and safety profile of a single particular intravitreal antivascular endothelial growth factor agent, aflibercept. Keywords: diabetic macular edema, aflibercep

Using a 2-Stage Strategy with Respondent-Driven Sampling to Recruit a Hard-to-Reach Population for a Placebo Microbicide Gel Clinical Trial in Nellore, Andhra Pradesh (India)

Traditional recruitment methods for microbicide efficacy trials are labor intensive and may fail to reach high-risk hard-to-reach populations. We report duration of recruitment and lessons learned from a two-stage process to recruit female sex workers (FSWs) into a placebo microbicide trial, and examined characteristics associated with successful recruitment of peers who screened for and enrolled in the trial. FSWs were first recruited via respondent-driven sampling (RDS) to complete a survey and subsequently invited to screen for enrollment into a placebo microbicide trial taking place at a local clinic. It took 6 months to enroll 267 participants into the trial. Successful recruiters of peers who enrolled were more likely to have enrolled themselves (AOR 2.0, CI 1.3–2.9) and less likely to visit Nellore city (AOR 0.5, CI 0.3–0.9). Recruitment of FSWs via a two-stage recruitment strategy with RDS can be a good option for future clinical trials