Transcriptional Regulation of Rod Photoreceptor Homeostasis Revealed by In Vivo NRL Targetome Analysis

A stringent control of homeostasis is critical for functional maintenance and survival of neurons. In the mammalian retina, the basic motif leucine zipper transcription factor NRL determines rod versus cone photoreceptor cell fate and activates the expression of many rod-specific genes. Here, we report an integrated analysis of NRL-centered gene regulatory network by coupling chromatin immunoprecipitation followed by high-throughput sequencing (ChIP–Seq) data from Illumina and ABI platforms with global expression profiling and in vivo knockdown studies. We identified approximately 300 direct NRL target genes. Of these, 22 NRL targets are associated with human retinal dystrophies, whereas 95 mapped to regions of as yet uncloned retinal disease loci. In silico analysis of NRL ChIP–Seq peak sequences revealed an enrichment of distinct sets of transcription factor binding sites. Specifically, we discovered that genes involved in photoreceptor function include binding sites for both NRL and homeodomain protein CRX. Evaluation of 26 ChIP–Seq regions validated their enhancer functions in reporter assays. In vivo knockdown of 16 NRL target genes resulted in death or abnormal morphology of rod photoreceptors, suggesting their importance in maintaining retinal function. We also identified histone demethylase Kdm5b as a novel secondary node in NRL transcriptional hierarchy. Exon array analysis of flow-sorted photoreceptors in which Kdm5b was knocked down by shRNA indicated its role in regulating rod-expressed genes. Our studies identify candidate genes for retinal dystrophies, define cis-regulatory module(s) for photoreceptor-expressed genes and provide a framework for decoding transcriptional regulatory networks that dictate rod homeostasis

A phase 3, double-blind, randomized placebo-controlled efficacy and safety study of abiraterone acetate in chemotherapy-naïve patients with mCRPC in China, Malaysia, Thailand and Russia

Objective: This double-blind, placebo-controlled phase 3 study was designed to compare efficacy and safety of abiraterone acetate + prednisone (abiraterone) to prednisone alone in chemotherapy-naïve, asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer (mCRPC) patients from China, Malaysia, Thailand and Russia. Methods: Adult chemotherapy-naïve patients with confirmed prostate adenocarcinoma, Eastern Cooperative Oncology Group (ECOG) performance status (PS) grade 0–1, ongoing androgen deprivation (serum testosterone <50 ng/dL) with prostate specific antigen (PSA) or radiographic progression were randomized to receive abiraterone acetate (1000 mg, QD) + prednisone (5 mg, BID) or placebo + prednisone (5 mg, BID), until disease progression, unacceptable toxicity or consent withdrawal. Primary endpoint was improvements in time to PSA progression (TTPP). Results: Totally, 313 patients were randomized (abiraterone: n = 157; prednisone: n = 156); and baseline characteristics were balanced. At clinical cut-off (median follow-up time: 3.9 months), 80% patients received treatment (abiraterone: n = 138, prednisone: n = 112). Median time to PSA progression was not reached with abiraterone versus 3.8 months for prednisone, attaining 58% reduction in PSA progression risk (HR = 0.418; p < 0.0001). Abiraterone-treated patients had higher confirmed PSA response rate (50% vs. 21%; relative odds = 2.4; p < 0.0001) and were 5 times more likely to achieve radiographic response than prednisone-treated patients (22.9% vs. 4.8%, p = 0.0369). Median survival was not reached. Most common (≥10% abiraterone vs. prednisone-treated) adverse events: bone pain (7% vs. 14%), pain in extremity (6% vs. 12%), arthralgia (10% vs. 8%), back pain (7% vs. 11%), and hypertension (15% vs. 14%). Conclusion: Interim analysis confirmed favorable benefit-to-risk ratio of abiraterone in chemotherapy-naïve men with mCRPC, consistent with global study, thus supporting use of abiraterone in this patient population

Topoisomerase 3β knockout mice show transcriptional and behavioural impairments associated with neurogenesis and synaptic plasticity

Topoisomerase 3β (Top3β) solves topological stress in DNA or RNA metabolism and its mutations are linked to mental disorders. Here, the authors describe transcriptional and behavioural impairments in Top3β-knockout mice and show that these are linked to impaired neurogenesis and synaptic plasticity