Proximity-driven site-specific cyclization of phage-displayed peptides.

Cyclization provides a general strategy for improving the proteolytic stability, cell membrane permeability and target binding affinity of peptides. Insertion of a stable, non-reducible linker into a disulphide bond is a commonly used approach for cyclizing phage-displayed peptides. However, among the vast collection of cysteine reactive linkers available, few provide the selectivity required to target specific cysteine residues within the peptide in the phage display system, whilst sparing those on the phage capsid.

The effect of air quality on sleep and cognitive performance in school children aged 10-12 years: a double-blinded, placebo-controlled, crossover trial.

Objectives: To investigate the effect of CO during sleep on next-morning cognitive performance in young schoolchildren, the authors performed a double-blind fully balanced crossover placebo-controlled study.

Material And Methods: The authors included 36 children aged 10-12 years in the climate chamber. The children slept at 21°C in 6 groups each at 3 different conditions separated by 7 days in a random order.

Mechanistic insights into the rational design of masked antibodies.

Although monoclonal antibodies have greatly improved cancer therapy, they can trigger side effects due to on-target, off-tumor toxicity. Over the past decade, strategies have emerged to successfully mask the antigen-binding site of antibodies, such that they are only activated at the relevant site, for example, after proteolytic cleavage. However, the methods for designing an ideal affinity-based mask and what parameters are important are not yet well understood.

Controlled masking and targeted release of redox-cycling ortho-quinones via a C-C bond-cleaving 1,6-elimination.

Natural products that contain ortho-quinones show great potential as anticancer agents but have been largely discarded from clinical development because their redox-cycling behaviour results in general systemic toxicity. Here we report conjugation of ortho-quinones to a carrier, which simultaneously masks their underlying redox activity. C-benzylation at a quinone carbonyl forms a redox-inactive benzyl ketol.

The Effect of Seasonal Priming on Specific Inhalation Challenges With Birch and Grass Allergen Among Persons With Allergic Rhinitis.

Allergic diseases are prevalent in the working population, and work-related airborne pollen exposure might be substantial, especially among outdoor workers, resulting in work-exacerbated effects. Seasonal exposure to pollen may induce a priming effect on the allergic bronchial response resulting in exaggerated effects at the end of the natural pollen season. This was previously observed among people with asthma but may also be of importance for persons with allergic rhinitis.

Single Mutation on Trastuzumab Modulates the Stability of Antibody-Drug Conjugates Built Using Acetal-Based Linkers and Thiol-Maleimide Chemistry.

Antibody-drug conjugates (ADCs) are a class of targeted therapeutics used to selectively kill cancer cells. It is important that they remain intact in the bloodstream and release their payload in the target cancer cell for maximum efficacy and minimum toxicity. The development of effective ADCs requires the study of factors that can alter the stability of these therapeutics at the atomic level.

A Platform for Site-Specific DNA-Antibody Bioconjugation by Using Benzoylacrylic-Labelled Oligonucleotides.

Many bioconjugation strategies for DNA oligonucleotides and antibodies suffer limitations, such as site-specificity, stoichiometry and hydrolytic instability of the conjugates, which makes them unsuitable for biological applications. Here, we report a new platform for the preparation of DNA-antibody bioconjugates with a simple benzoylacrylic acid pentafluorophenyl ester reagent. Benzoylacrylic-labelled oligonucleotides prepared with this reagent can be site-specifically conjugated to a range of proteins and antibodies through accessible cysteine residues.

Dichloro Butenediamides as Irreversible Site-Selective Protein Conjugation Reagent.

We describe maleic-acid derivatives as robust cysteine-selective reagents for protein labelling with comparable kinetics and superior stability relative to maleimides. Diamide and amido-ester derivatives proved to be efficient protein-labelling species with a common mechanism in which a spontaneous cyclization occurs upon addition to cysteine. Introduction of chlorine atoms in their structures triggers ring hydrolysis or further conjugation with adjacent residues, which results in conjugates that are completely resistant to retro-Michael reactions in the presence of biological thiols and human plasma.

The Human and Mouse Islet Peptidome: Effects of Obesity and Type 2 Diabetes, and Assessment of Intraislet Production of Glucagon-like Peptide-1.

To characterize the impact of metabolic disease on the peptidome of human and mouse pancreatic islets, LC-MS was used to analyze extracts of human and mouse islets, purified mouse alpha, beta, and delta cells, supernatants from mouse islet incubations, and plasma from patients with type 2 diabetes. Islets were obtained from healthy and type 2 diabetic human donors, and mice on chow or high fat diet. All major islet hormones were detected in lysed islets as well as numerous peptides from vesicular proteins including granins and processing enzymes.

Interconversion of Unexpected Thiol States Affects the Stability, Structure, and Dynamics of Antibody Engineered for Site-Specific Conjugation.

Antibody-drug conjugates have become one of the most actively developed classes of drugs in recent years. Their great potential comes from combining the strengths of large and small molecule therapeutics: the exquisite specificity of antibodies and the highly potent nature of cytotoxic compounds. More recently, the approach of engineering antibody-drug conjugate scaffolds to achieve highly controlled drug to antibody ratios has focused on substituting or inserting cysteines to facilitate site-specific conjugation.

Acute health effects from exposure to indoor ultrafine particles-A randomized controlled crossover study among young mild asthmatics.

Particulate matter is linked to adverse health effects, however, little is known about health effects of particles emitted from typical indoor sources. We examined acute health effects of short-term exposure to emissions from cooking and candles among asthmatics. In a randomized controlled double-blinded crossover study, 36 young non-smoking asthmatics attended three exposure sessions lasting 5 h: (a) air mixed with emissions from cooking (fine particle mass concentration): (PM : 96.

An RCT of acute health effects in COPD-patients after passive vape exposure from e-cigarettes.

: E-cigarette use has been shown to have short-term acute effects among active users but less is known of the acute passive effects, particularly among individuals with existing respiratory diseases. : To investigate local and systemic effects of short-term passive vape exposure among patients with mild or moderate chronic obstructive pulmonary disease (COPD). : In a double-blinded crossover study 16 non-smoking COPD-patients (mean age 68) were randomly exposed for 4 h to passive vape (median PM: 18 µg/m (range: 8-333)) and clean air (PM < 6 µg/m) separated by 14 days.

Gut Hormone GIP Induces Inflammation and Insulin Resistance in the Hypothalamus.

The hypothalamus plays a critical role in controlling energy balance. High-fat diet (HFD) feeding increases the gene expression of proinflammatory mediators and decreases insulin actions in the hypothalamus. Here, we show that a gut-derived hormone, glucose-dependent insulinotropic polypeptide (GIP), whose levels are elevated during diet-induced obesity, promotes and mediates hypothalamic inflammation and insulin resistance during HFD-induced obesity.

Discordance between GLP-1R gene and protein expression in mouse pancreatic islet cells.

The insulinotropic actions of glucagon-like peptide 1 receptor (GLP-1R) in β-cells have made it a useful target to manage type 2 diabetes. Metabolic stress reduces β-cell sensitivity to GLP-1, yet the underlying mechanisms are unknown. We hypothesized that expression is heterogeneous among β-cells and that metabolic stress decreases the number of GLP-1R-positive β-cells.

Pharmacological antagonism of the incretin system protects against diet-induced obesity.

Objective: Glucose-dependent insulinotropic polypeptide is an intestinally derived hormone that is essential for normal metabolic regulation. Loss of the GIP receptor (GIPR) through genetic elimination or pharmacological antagonism reduces body weight and adiposity in the context of nutrient excess. Interrupting GIPR signaling also enhances the sensitivity of the receptor for the other incretin peptide, glucagon-like peptide 1 (GLP-1).

Improved Physical Stability of an Antibody-Drug Conjugate Using Host-Guest Chemistry.

Antibody-drug conjugates (ADCs) are an emerging class of biopharmaceutical products for oncology, with the cytotoxic pyrrolobenzodiazepine (PBD) family of "warheads" well-established in the clinic. While PBDs offer high potency, they are also characterized by their hydrophobicity, which can make formulation of the ADC challenging. Several approaches have been investigated to improve the physicochemical properties of PBD-containing ADCs, and herein a supramolecular approach was explored using cucurbit[8]uril (CB[8]).

Gut-derived GIP activates central Rap1 to impair neural leptin sensitivity during overnutrition.

Nutrient excess, a major driver of obesity, diminishes hypothalamic responses to exogenously administered leptin, a critical hormone of energy balance. Here, we aimed to identify a physiological signal that arises from excess caloric intake and negatively controls hypothalamic leptin action. We found that deficiency of the gastric inhibitory polypeptide receptor (Gipr) for the gut-derived incretin hormone GIP protected against diet-induced neural leptin resistance.

Important Role of the GLP-1 Axis for Glucose Homeostasis after Bariatric Surgery.

Bariatric surgery is widely used to treat obesity and improves type 2 diabetes beyond expectations from the degree of weight loss. Elevated post-prandial concentrations of glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and insulin are widely reported, but the importance of GLP-1 in post-bariatric physiology remains debated. Here, we show that GLP-1 is a major driver of insulin secretion after bariatric surgery, as demonstrated by blocking GLP-1 receptors (GLP1Rs) post-gastrectomy in lean humans using Exendin-9 or in mice using an anti-GLP1R antibody.

Development and characterisation of a novel glucagon like peptide-1 receptor antibody.

Aims/hypothesis: Glucagon like peptide-1 (GLP-1) enhances glucose-dependent insulin secretion by binding to GLP-1 receptors (GLP1Rs) on pancreatic beta cells. GLP-1 mimetics are used in the clinic for the treatment of type 2 diabetes, but despite their therapeutic success, several clinical effects of GLP-1 remain unexplained at a mechanistic level, particularly in extrapancreatic tissues. The aim of this study was to generate and characterise a monoclonal antagonistic antibody for the GLP1R for use in vivo.

Superior reductions in hepatic steatosis and fibrosis with co-administration of a glucagon-like peptide-1 receptor agonist and obeticholic acid in mice.

Objective: Nonalcoholic steatohepatitis (NASH) is an unmet need associated with metabolic syndrome. There are no approved therapies for NASH; however, glucagon-like peptide-1 receptor (GLP-1R) and farnesoid-X receptor (FXR) agonists are promising drug targets. We investigated the therapeutic effects of co-administration of a GLP-1R agonist, IP118, with FXR agonist obeticholic acid (OCA) in mice.

A simple supramolecular assay for drug detection in urine.

A supramolecular colorimetric assay utilising the macrocyclic host cucurbit[7]uril (CB[7]) with a commercial dye molecule, neutral red (NR), was evaluated as a novel method for drug detection in urine of a model therapeutic peptide drug Octreotide.

High Affinity Recognition of a Selected Amino Acid Epitope within a Protein by Cucurbit[8]uril Complexation.

Supramolecular interactions between the host cucurbit[8]uril (CB[8]) and amino acids have been widely interrogated, but recognition of specific motifs within a protein domain have never been reported. A phage display approach was herein used to select motifs with the highest binding affinity for the heteroternary complex with methyl viologen and CB[8] (MV⋅CB[8]) within a vast pool of cyclic peptide sequences. From the selected motifs, an epitope consisting of three amino acid was extrapolated and incorporated into a solvent-exposed loop of a protein domain; the protein exhibited micromolar binding affinity for the MV⋅CB[8] complex, matching that of the cyclic peptide.

Use of CRISPR/Cas9-engineered INS-1 pancreatic β cells to define the pharmacology of dual GIPR/GLP-1R agonists.

Dual-agonist molecules combining glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) activity represent an exciting therapeutic strategy for diabetes treatment. Although challenging due to shared downstream signalling pathways, determining the relative activity of dual agonists at each receptor is essential when developing potential novel therapeutics. The challenge is exacerbated in physiologically relevant cell systems expressing both receptors.

Recombinant expression and in vitro characterisation of active Huwentoxin-IV.

Huwentoxin-IV (HwTx-IV) is a 35-residue neurotoxin peptide with potential application as a novel analgesic. It is a member of the inhibitory cystine knot (ICK) peptide family, characterised by a compact globular structure maintained by three intramolecular disulfide bonds. Here we describe a novel strategy for producing non-tagged, fully folded ICK-toxin in a bacterial system.