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GDNF receptor alpha-like is a brainstem-restricted receptor for growth and differentiation factor 15, regulating appetite and body weight in non-homeostatic conditions by activating the emergency circuit response to disease and toxin stresses. Brainstem receptor regulates body mass loss Growth and differentiation factor 15 (GDF15) acts on feeding centres in the brain to cause anorexia, leading to loss of both lean and fat mass and eventually cachexia. GDF15 levels rise in response to tissue stress and injury, and higher levels are associated with weight loss in numerous chronic human diseases, including cancer. Bernard Allan and colleagues now show that glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) is a GDF15 receptor in the brainstem. The structure of GDF15 and its interaction with GFRAL together with biochemical experiments and analysis of Gfral knockout mice demonstrate that regulation of body weight by GFRAL is independent of previously characterized pathways. Unlike hormones from gut and adipose tissue that activate receptors mostly in the hypothalamus, GDF15 increases in response to tissue damage and activates GFRAL-expressing neurons in the brainstem. Gfral knockout mice overate under stressed conditions and were resistant to chemotherapy-induced anorexia and weight loss. These findings provide therapeutic opportunities for disorders with altered energy demands. Under homeostatic conditions, animals use well-defined hypothalamic neural circuits to help maintain stable body weight, by integrating metabolic and hormonal signals from the periphery to balance food consumption and energy expenditure 1 , 2 . In stressed or disease conditions, however, animals use alternative neuronal pathways to adapt to the metabolic challenges of altered energy demand 3 . Recent studies have identified brain areas outside the hypothalamus that are activated under these ‘non-homeostatic’ conditions 4 , 5 , 6 , but the molecular nature of the peripheral signals and brain-localized receptors that activate these circuits remains elusive. Here we identify glial cell-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) as a brainstem-restricted receptor for growth and differentiation factor 15 (GDF15). GDF15 regulates food intake, energy expenditure and body weight in response to metabolic and toxin-induced stresses; we show that Gfral knockout mice are hyperphagic under stressed conditions and are resistant to chemotherapy-induced anorexia and body weight loss. GDF15 activates GFRAL-expressing neurons localized exclusively in the area postrema and nucleus tractus solitarius of the mouse brainstem. It then triggers the activation of neurons localized within the parabrachial nucleus and central amygdala, which constitute part of the ‘emergency circuit’ that shapes feeding responses to stressful conditions 7 . GDF15 levels increase in response to tissue stress and injury, and elevated levels are associated with body weight loss in numerous chronic human diseases 8 , 9 . By isolating GFRAL as the receptor for GDF15-induced anorexia and weight loss, we identify a mechanistic basis for the non-homeostatic regulation of neural circuitry by a peripheral signal associated with tissue damage and stress. These findings provide opportunities to develop therapeutic agents for the treatment of disorders with altered energy demand.

Microsatellite analysis is a powerful tool for the assessment of genetic instability and loss of heterozygosity in cancer cells. However, most human tumors harbor significant numbers of normal cells, which may contribute to false-negative results. Recent techniques based on fluorescently labeled primers and semiautomated capillary electrophoresis of polymerase chain reaction (PCR) products allow a reliable quantitative assessment of (PCR) products while requiring very small numbers of cells. We report a highly sensitive protocol for the semiautomated analysis of allelic imbalance based on time-release PCR and capillary electrophoresis. With this protocol, as few as 100 cells can be used to reliably assess allelic imbalance (AI) in DNA samples. Using a panel of seven microsatellite markers, we determined allelic variation in a large set of heterozygous lymphocyte DNA samples and examined the use of different statistical analysis techniques. Using these statistical approaches, we describe a calibration method to evaluate AI from microsatellite results. Using a simple formula, cutoff points at preset confidence levels are used to decide whether allelic imbalance exists in a given sample at the loci under investigation. Our method allows the reliable detection of AI with very small amounts of DNA, and is sufficiently quantitative to assess allelic ratios in nonclonal tissue specimens.

Nature 550, 255–259 (2017); doi:10.1038/nature24042 Owing to an error during the production process, in Fig. 2c of this Letter, all four groups of mice were incorrectly labelled as ‘WT’ (wild type), but the two groups on the left (filled and open blue boxes) should have been labelled ‘WT’, whereas the two groups on the right (filled and open yellow boxes) should have been labelled ‘KO’ (knockout), as in the key for Fig. 2b. The original Letter has been corrected online.

This thesis includes work from three major projects. In the first chapter I describe work on the structural heterogeneity of the folding intermediate of RNase H. In this project we were able to populate the kinetic intermediate of RNase H at equilibrium with a mutation that strategically disrupted the native state. By populating this intermediate at equilibrium, we were able to characterize it by NMR and show that it is a highly dynamic conformation. The second chapter presents work using hydrophobic core repacking to manipulate protein function. We used a constrained directed evolution approach to generate novel function in the transcriptional activator MarA. We created libraries of core mutations and selected for core mutants that could stimulate transcription with a novel promoter sequence. Our results demonstrated that reorganization of the core alone can be sufficient to drive the evolution of novel function. Finally, in the appendix, I describe my work in trying to isolate and characterize a class of mutations in ligand binding proteins which are vitamin remedial. Remedial mutations are those which disrupt protein function, but can be reversed with elevated levels of cofactor. Vitamin remediation is particularly interesting for its therapeutic benefits in the case of mutations linked to heritable disease. We hypothesized that vitamin remedial mutations might be simply derived from shifts in protein stability. To characterize the vitamin remedial effects of mutations in folate-binding proteins, we coupled in vivo evidence for folate-responsive growth to biophysically measured changes in stability and binding.

C‐reactive protein (CRP) is an early‐stage acute phase protein and highly upregulated in response to inflammatory reactions. We recently identified a novel mechanism that leads to a conformational change from the native, functionally relatively inert, pentameric CRP (pCRP) structure to a pentameric CRP intermediate (pCRP*) and ultimately to the monomeric CRP (mCRP) form, both exhibiting highly pro‐inflammatory effects. This transition in the inflammatory profile of CRP is mediated by binding of pCRP to activated/damaged cell membranes via exposed phosphocholine lipid head groups. We designed a tool compound as a low molecular weight CRP inhibitor using the structure of phosphocholine as a template. X‐ray crystallography revealed specific binding to the phosphocholine binding pockets of pCRP. We provide in vitro and in vivo proof‐of‐concept data demonstrating that the low molecular weight tool compound inhibits CRP‐driven exacerbation of local inflammatory responses, while potentially preserving pathogen‐defense functions of CRP. The inhibition of the conformational change generating pro‐inflammatory CRP isoforms via phosphocholine‐mimicking compounds represents a promising, potentially broadly applicable anti‐inflammatory therapy. Synopsis A novel low molecular weight compound C10M was designed to block the PC binding site on pCRP, thereby inhibiting the formation of the pro‐inflammatory isoforms pCRP*/mCRP, and thus showing broad anti‐inflammatory effects in vitro and in vivo . The feasibility of the monovalent approach of PC binding site inhibition was demonstrated directly by X‐ray crystallography. The pro‐inflammatory conformational change of pCRP was blocked by a novel monovalent inhibitor utilizing the PC binding site, leaving the B‐face otherwise accessible. The compound C10M inhibited pCRP*/mCRP‐dependent pro‐inflammatory effects on endothelial cells, monocytes and leukocytes in vitro . pCRP*/mCRP‐driven inflammation in renal ischemia/reperfusion‐injury and VCA hindlimb rejection in vivo was markedly inhibited by C10M. Graphical Abstract A novel low molecular weight compound C10M was designed to block the PC binding site on pCRP, thereby inhibiting the formation of the pro‐inflammatory isoforms pCRP*/mCRP, and thus showing broad anti‐inflammatory effects in vitro and in vivo .

The Y-dwarf WISE 1828+2650 is one of the coldest known brown dwarfs with an effective temperature of ∼300 K. Located at a distance of just 10 pc, previous model-based estimates suggest WISE1828+2650 has a mass of ∼5–10 M J, making it a valuable laboratory for understanding the formation, evolution, and physical characteristics of gas giant planets. However, previous photometry and spectroscopy have presented a puzzle, with the near impossibility of simultaneously fitting both the short- (0.9–2.0 μm) and long-wavelength (3–5 μm) data. A potential solution to this problem has been the suggestion that WISE 1828+2650 is a binary system whose composite spectrum might provide a better match to the data. Alternatively, new models being developed to fit JWST/NIRSpec, and MIRI spectroscopy might provide new insights. This article describes JWST/NIRCam observations of WISE 1828+2650 in six filters to address the binarity question and to provide new photometry to be used in model fitting. We also report adaptive optics imaging with the Keck I0 m telescope. We find no evidence for multiplicity for a companion beyond 0.5 au with either JWST or Keck. Companion articles will present low- and high-resolution spectra of WISE 1828 obtained with both NIRSpec and MIRI.

Abstract Background Bromodomain and extra-terminal domain proteins are promising epigenetic anticancer drug targets. This first-in-human study evaluated the safety, recommended phase II dose, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of the bromodomain and extra-terminal domain inhibitor molibresib (GSK525762) in patients with nuclear protein in testis (NUT) carcinoma (NC) and other solid tumors. Methods This was a phase I and II, open-label, dose-escalation study. Molibresib was administered orally once daily. Single-patient dose escalation (from 2 mg/d) was conducted until the first instance of grade 2 or higher drug-related toxicity, followed by a 3 + 3 design. Pharmacokinetic parameters were obtained during weeks 1 and 3. Circulating monocyte chemoattractant protein-1 levels were measured as a pharmacodynamic biomarker. Results Sixty-five patients received molibresib. During dose escalation, 11% experienced dose-limiting toxicities, including six instances of grade 4 thrombocytopenia, all with molibresib 60–100 mg. The most frequent treatment-related adverse events of any grade were thrombocytopenia (51%) and gastrointestinal events, including nausea, vomiting, diarrhea, decreased appetite, and dysgeusia (22%–42%), anemia (22%), and fatigue (20%). Molibresib demonstrated an acceptable safety profile up to 100 mg; 80 mg once daily was selected as the recommended phase II dose. Following single and repeat dosing, molibresib showed rapid absorption and elimination (maximum plasma concentration: 2 hours; t1/2: 3–7 hours). Dose-dependent reductions in circulating monocyte chemoattractant protein-1 levels were observed. Among 19 patients with NC, four achieved either confirmed or unconfirmed partial response, eight had stable disease as best response, and four were progression-free for more than 6 months. Conclusions Once-daily molibresib was tolerated at doses demonstrating target engagement. Preliminary data indicate proof-of-concept in NC.

The most prominent of the IRAS debris disk systems, α Lyrae (Vega), at a distance of 7.7 pc, has been observed by both the NIRCam and MIRI instruments on the James Webb Space Telescope. This paper describes NIRCam coronagraphic observations, which have achieved F444W contrast levels of 3 × 10−7 at 1″ (7.7 au), 1 × 10−7 at 2″ (15 au), and a few × 10−8 beyond 5″ (38 au), corresponding to masses of <3, 2, and 0.5 M J for a system age of 700 Myr. Two F444W objects are identified in the outer MIRI debris disk, around 48 au. One of these is detected by MIRI and appears to be extended with a spectral energy distribution similar to those of distant extragalactic sources. The second one also appears extended in the NIRCam data suggestive of an extragalactic nature. The NIRCam limits within the inner disk (1″–10″) correspond to model-dependent masses of 2–3 M J. K. Y. L. Su et al. argue that planets larger than 0.3 M J would disrupt the smooth disk structure seen at MIRI wavelengths. Eight additional objects are found within 60″ of Vega, but none have astrometric properties or colors consistent with planet candidates. These observations reach a level consistent with expected Jeans mass limits. Deeper observations achieving contrast levels < 10−8 outside of ∼4″ and reaching masses below that of Saturn are possible, but may not reveal a large population of new objects.