Tyrosine Sulfation Modulates the Binding Affinity of Chemokine-Targeting Nanobodies.

Chemokines are an important family of small proteins integral to leukocyte recruitment during inflammation. Dysregulation of the chemokine-chemokine receptor axis is implicated in many diseases, and both chemokines and their cognate receptors have been the targets of therapeutic development. Analysis of the antigen-binding regions of chemokine-binding nanobodies revealed a sequence motif suggestive of tyrosine sulfation. Given the well-established importance of post-translational tyrosine sulfation of receptors for chemokine affinity, it was hypothesized that the sulfation of these nanobodies may contribute to chemokine binding and selectivity. Four nanobodies (16C1, 9F1, 11B1, and 11F2) were expressed using amber codon suppression to incorporate tyrosine sulfation. The sulfated variant of 16C1 demonstrated significantly improved chemokine binding compared to the non-sulfated counterpart, while the other nanobodies displayed equipotent or reduced affinity upon sulfation. The ability of tyrosine sulfation to modulate chemokine binding, both positively and negatively, could be leveraged for chemokine-targeted sulfo-nanobody therapeutics in the future.

Unravelling G protein-coupled receptor signalling networks using global phosphoproteomics.

G protein-coupled receptor (GPCR) activation initiates signalling via a complex network of intracellular effectors that combine to produce diverse cellular and tissue responses. Although we have an advanced understanding of the proximal events following receptor stimulation, the molecular detail of GPCR signalling further downstream often remains obscure. Unravelling these GPCR-mediated signalling networks has important implications for receptor biology and drug discovery. In this context, phosphoproteomics has emerged as a powerful approach for investigating global GPCR signal transduction. Here, we provide a brief overview of the phosphoproteomic workflow and discuss current limitations and future directions for this technology. By highlighting some of the novel insights into GPCR signalling networks gained using phosphoproteomics, we demonstrate the utility of global phosphoproteomics to dissect GPCR signalling networks and to accelerate discovery of new targets for therapeutic development.

Loot box spending is associated with problem gambling but not mental wellbeing.

There are emerging concerns that loot boxes-digital video game items that can be purchased for a chance at randomized rewards-are associated with problematic gambling behaviours and, in turn, are potentially harmful. Current research suggests consistent correlations between loot box spending (LS) and problematic gambling symptomology; however, little research has looked at relationships with mental wellbeing. Here, we used a Bayesian hypothesis testing framework to assess the relative strength of evidence for relationships between LS, excessive gaming, problem gambling, mental wellbeing and psychological distress. Two thousand seven hundred twenty-eight participants who reported playing games containing loot box mechanics in the past month answered a survey assessing the above measures, as well as other forms of digital spending. The results showed extremely strong evidence for a positive correlation between LS and problem gambling; however, there was no evidence to suggest relationships between such spending and mental wellbeing or psychological distress. Exploratory results suggested that individuals who spend money on loot boxes also spend more across a range of digital purchases generally. The findings highlight an urgent need to understand what constitutes harm when considering LS effects and provide further context for discussions regarding how best to regulate such mechanisms.

Non-sulfated cholecystokinin-8 reduces meal size and prolongs the intermeal interval in male Sprague Dawley rats.

The current study measured seven feeding responses by non-sulfated cholecystokinin-8 (NS CCK-8) in freely fed adult male Sprague Dawley rats. The peptide (0, 0.5, 1, 3, 5 and 10 nmol/kg) was given intraperitoneally (ip) prior to the onset of the dark cycle, and first meal size (MS), second meal size, intermeal interval (IMI) length, satiety ratio (SR = IMI/MS), latency to first meal, duration of first meal, number of meals and 24-hour food intake were measured. We found that NS CCK-8 (0.5 and 1.0 nmol/kg) reduced MS, prolonged IMI length and increased SR during the dark cycle. Furthermore, the specific CCK-B receptor antagonist L365, 260 (1 mg/kg, ip) attenuated these responses. These results support a possible role for NS CCK-8 in regulating food intake.