Jason A. Moss

Vaccination against weight gain

Obesity endangers the lives of millions of people worldwide, through comorbidities such as heart disease, cancers, type 2 diabetes, stroke, arthritis, and major depression. New approaches to control body weight remain a high priority. Vaccines traditionally have been used to protect against infectious diseases and, more recently, for unconventional targets such as drug addiction. Methodologies that could specifically modulate the bioavailability of an endogenous molecule that regulates energy balance might provide a new foundation for treating obesity. Here we show that active vaccination of mature rats with ghrelin immunoconjugates decreases feed efficiency, relative adiposity, and body weight gain in relation to the immune response elicited against ghrelin in its active, acylated form. Three active vaccines based on the 28-aa residue sequence of ghrelin, a gastric endocrine hormone, were used to immunize adult male Wistar rats (n = 17). Synthetic ghrelin analogs were prepared that spanned residues 1–10 [ghrelin (1–10) Ser-3(butanoyl) hapten, Ghr1], 13–28 [ghrelin (13–28) hapten, Ghr2], and 1–28 [ghrelin(1–28) Ser-3(butanoyl) hapten, Ghr3], and included n-butanoyl esters at Ser-3. Groups immunized with Ghr1 or Ghr3 showed greater and more selective plasma binding capacity for the active, Ser-3-(n-octanoyl) form of ghrelin as compared with Ghr2 or keyhole limpet hemocyanin vaccinated controls. Accordingly, they gained less body weight, with sparing of lean mass and preferential reduction of body fat, consistent with reduced circulating leptin levels. The ratio of brain/serum ghrelin levels was lower in rats with strong anti-ghrelin immune responses. Effects were not attributable to nonspecific inflammatory responses. Vaccination against the endogenous hormone ghrelin can slow weight gain in rats by decreasing feed efficiency.

Catalytic antibody degradation of ghrelin increases whole-body metabolic rate and reduces refeeding in fasting mice

Obesity is a chronic, costly, and globally prevalent condition, with excess caloric intake a suspected etiologic factor. Nonsurgical treatments are modestly efficacious, and weight loss maintenance is hampered by anti-famine homeostatic mechanisms. Ghrelin, a gastric hormone linked to meal initiation, energy expenditure, and fuel partitioning, is hypothesized to facilitate weight gain and impede weight loss. Unique among known animal peptides, the serine-3 residue of ghrelin is posttranslationally acylated with an n-octanoic acid, a modification important for the peptides active blood-brain transport and growth hormone secretagogue receptor-1 agonist activity. Pharmacological degradation of ghrelin would be hypothesized to reduce ghrelins biological effects. To study endogenous ghrelins role in appetite and energy expenditure, we generated antibodies that hydrolyze the octanoyl moiety of ghrelin to form des-acyl ghrelin. The most proficient antibody catalyst, GHR-11E11, was found to display a second-order rate constant of 18 M−1·s−1 for the hydrolysis of ghrelin to des-acyl ghrelin. I.v. administration of GHR-11E11 (50 mg/kg) maintained a greater metabolic rate in fasting C57BL/6J mice as compared with mice receiving a control antibody and suppressed 6-h refeeding after 24 h of food deprivation. Indirect respiratory measures of metabolism after refeeding and relative fuel substrate utilization were unaffected. The results support the hypothesis that acylated ghrelin stimulates appetite and curbs energy expenditure during deficient energy intake, whereas des-acyl ghrelin does not potently share these functions. Catalytic anti-ghrelin antibodies might thereby adjunctively aid consolidation of caloric restriction-induced weight loss and might also be therapeutically relevant to Prader–Willi syndrome, characterized after infancy by hyperghrelinemia, hyperphagia, and obesity.

A New and Improved Method for Deglycosidation of Glycopeptide Antibiotics Exemplified with Vancomycin, Ristocetin, and Ramoplanin

A general method for the deglycosidation of glycopeptide antibiotics has been developed. Treatment of vancomycin, ristocetin, and ramoplanin with anhydrous HF results in efficient cleavage of the sugars to provide the corresponding aglycons in high yield.

Solid phase peptide synthesis on JandaJelTM resin

Abstract A comparative synthesis of the classic difficult sequence ACP(65–74) on 2% crosslinked J anda J el and 1% crosslinked polystyrene–divinylbenzene, (PS–DVB, Merrifield resin) by Boc/benzyl chemistry is presented. The J anda J el batch used was of nearly double the loading of PS–DVB, yet 12.2% less of the des -Val 65 contaminant was observed in the J anda J el synthesis. These results suggest that the increased swelling of the J anda J el resin relative to traditional Merrifield resin afforded a higher yield of the pure peptide by permitting greater solvent-mediated disruption of secondary structure in the resin-bound peptide.

Guide for Resin and Linker Selection in Solid‐Phase Peptide Synthesis

For both novice and experienced practitioners of solid‐phase peptide synthesis (SPPS), the vast selection of commercially available linkers and resins has become something of a babel. The purpose of this unit is to clarify the situation, which is best understood by distillation to first principles, through an appreciation of chemical trends and consequences, as well as practical considerations. The most commonly used linkers and resins are presented and described in detail, along with a description of their development and common applications. Key protocols are provided so that the user may prepare appropriate linker‐functionalized resins for the majority of peptide synthesis applications.

Discovering Additional Chemical and Biological Functions for 3-Oxo-N-Acylhomoserine Lactones

Introduction The term quorum sensing has been coined to describe the ability of a population of unicellular bacteria to act as a multicellular organism in a cell-density-dependent manner, that is, a way to sense “how many are out there” [1]. Bacteria use small diffusible molecules to exchange information amongst themselves. An important class of autoinducers is the family of N-acylhomoserine lactones (AHLs) used by Gram negative bacteria. Variation in N-acyl chain length and oxidation state of AHLs provide for bacterial strain specificity in the signaling process and subsequent synchronization of gene expression. Upon reaching a critical threshold concentration, they bind to their cognate receptor proteins, triggering the expression of target genes. Pseudomonas aeruginosa is a common environmental microorganism that has acquired the ability to take advantage of weaknesses in the host immune system to become an opportunistic pathogen in humans [2]. Over the last ten years, significant progress has been made in elucidating the molecular mechanisms underlying P. aeruginosa pathogenicity. Two different AHLs, N-(3-oxododecanoyl) homoserine lactone 1 and N-butyrylhomoserine lactone, have been identified as the main quorum sensing signaling molecules in P. aeruginosa [3]. Importantly, genes regulated by this mechanism control the expression of virulence factors as well as the formation of structures known as biofilms [4]. Recently, we have assigned new roles for these compounds through the demonstration that 1 performs a previously unrecognized role; the autoinducer itself and a corresponding degradation product derived from an unusual Claisen-like condensation reaction function as innate bactericidal agents [5].