Identification of an Endogenous Ligand Bound to a Native Orphan Nuclear Receptor

Orphan nuclear receptors have been instrumental in identifying novel signaling pathways and therapeutic targets. However, identification of ligands for these receptors has often been based on random compound screens or other biased approaches. As a result, it remains unclear in many cases if the reported ligands are the true endogenous ligands, – i.e., the ligand that is bound to the receptor in an unperturbed in vivo setting. Technical limitations have limited our ability to identify ligands based on this rigorous definition. The orphan receptor hepatocyte nuclear factor 4 α (HNF4α) is a key regulator of many metabolic pathways and linked to several diseases including diabetes, atherosclerosis, hemophilia and cancer. Here we utilize an affinity isolation/mass-spectrometry (AIMS) approach to demonstrate that HNF4α is selectively occupied by linoleic acid (LA, C18:2ω6) in mammalian cells and in the liver of fed mice. Receptor occupancy is dramatically reduced in the fasted state and in a receptor carrying a mutation derived from patients with Maturity Onset Diabetes of the Young 1 (MODY1). Interestingly, however, ligand occupancy does not appear to have a significant effect on HNF4α transcriptional activity, as evidenced by genome-wide expression profiling in cells derived from human colon. We also use AIMS to show that LA binding is reversible in intact cells, indicating that HNF4α could be a viable drug target. This study establishes a general method to identify true endogenous ligands for nuclear receptors (and other lipid binding proteins), independent of transcriptional function, and to track in vivo receptor occupancy under physiologically relevant conditions

Impact of Size and Distribution of k-Carbides on the Hydrogen Embrittlement and Trapping Behaviors of a Fe-Mn-Al-C Low-Density Steel

This study compares the hydrogen embrittlement susceptibility of a Fe-30Mn-8Al-1.2C austenitic low-density steel aged at 600 °C for 0 (RX), 1 min (A1) and 60 min (A60), each exhibiting varying sizes and distributions of nano-sized κ-carbides. Slow strain rate tests were conducted to assess hydrogen embrittlement susceptibility, while thermal desorption analysis was applied to investigate hydrogen trapping behaviors. Fracture surface analysis was employed to discuss the associated failure mechanisms. The results suggest that nano-sized κ-carbides with sizes ranging from 2–4 nm play a crucial role in mitigating hydrogen embrittlement, contrasting with the exacerbating effect of coarse grain boundary κ-carbides. This highlights the significance of controlling the sizes and morphology of precipitates in designing hydrogen-resistant materials

Conbercept for Treatment of Neovascular Age-related Macular Degeneration: Results of the Randomized Phase 3 PHOENIX Study

Age-related macular degeneration (AMD) can cause irreversible vision loss leading to blindness. We aim to evaluate the efficacy and safety of intravitreal injections of 0.5 mg conbercept, a new anti-vascular endothelial growth factor (anti-VEGF) drug, for treatment of AMD on a schedule more manageable for patients. A prospective, double-masked, multicenter, sham-controlled, phase III randomized trial. Patients: Patients with choroidal neovascularization (CNV) secondary to AMD were enrolled and randomized to the conbercept group or the sham control group. The conbercept group received intravitreal injections of conbercept (0.5 mg) once monthly for the first 3 months, then once quarterly until month 12 (3 + Q3M). The sham group received first 3 monthly sham injections and then 3 monthly injections of conbercept (0.5 mg) followed by quarterly administrations until month 12. The primary endpoint was mean change from baseline in best-corrected visual acuity (BCVA) at month 3. A total of 114 patients (91.9%) from 9 sites in China completed the 12-month study. At the 3-month primary endpoint, the mean changes in BCVA from baseline were +9.20 letters in the conbercept group and +2.02 letters in the sham group, respectively (P < .001). At 12 months, the mean changes from baseline in BCVA letter score were +9.98 letters in the conbercept group and +8.81 letters in the sham group (P = .64). The most common ocular adverse events were associated with intravitreal injections, such as conjunctival hemorrhage, and increased intraocular pressure. A conbercept dosing regimen of 3 initial monthly administrations followed by quarterly treatments is effective for treatment of AMD. In previous reports, other anti-VEGF agents were unable to maintain similar clinical benefits with the same regimen