Effects of Bacterial CLPB Protein Fragments on Food Intake and PYY Secretion.

Manon Dominique,Fatima Léon,Jean-Claude Do Rego,Pierre Déchelotte,Grégory Lambert,Romain Legrand,Nicolas Lucas,Camille Deroissart,Séverine Nobis,Illona-Marie Bouleté,Christine Bôle-Feysot

doi:10.3390/nu13072223

Abstract

CLPB (Caseinolytic peptidase B) protein is a conformational mimetic of α-MSH, an anorectic hormone. Previous in vivo studies have already shown the potential effect of CLPB protein on food intake and on the production of peptide YY (PYY) by injection of E. coli wild type (WT) or E. coli ΔClpB. However, until now, no study has shown its direct effect on food intake. Furthermore, this protein can fragment naturally. Therefore, the aim of this study was (i) to evaluate the in vitro effects of CLPB fragments on PYY production; and (ii) to test the in vivo effects of a CLPB fragment sharing molecular mimicry with α-MSH (CLPB25) compared to natural fragments of the CLPB protein (CLPB96). To do that, a primary culture of intestinal mucosal cells from male Sprague–Dawley rats was incubated with proteins extracted from E. coli WT and ΔCLPB after fragmentation with trypsin or after a heat treatment of the CLPB protein. PYY secretion was measured by ELISA. CLPB fragments were analyzed by Western Blot using anti-α-MSH antibodies. In vivo effects of the CLPB protein on food intake were evaluated by intraperitoneal injections in male C57Bl/6 and ob/ob mice using the BioDAQ® system. The natural CLPB96 fragmentation increased PYY production in vitro and significantly decreased cumulative food intake from 2 h in C57Bl/6 and ob/ob mice on the contrary to CLPB25. Therefore, the anorexigenic effect of CLPB is likely the consequence of enhanced PYY secretion.

Highlights

Obesity is a major public health problem
The application of α-melanocytestimulating hormone (α-MSH) on the basolateral mucosa of mice depleted of the melanocortin 4 receptor (MC4R) receptor (MC4R−/−) did not induce any secretion of peptide YY (PYY) [14]
Previous studies have revealed direct intermolecular contacts between amino acids that PYY production may be elicited at least in part via activation of MC4R stimulated by α-MSH

Summary

Introduction

Obesity is a major public health problem. In 2016, more than 650 million adults (>18 years old) were considered obese [1]. According to the World Health Organization (WHO, Geneva, Switzerland), obesity is defined by a BMI ≥ 30 kg/m2, significantly affecting the quality of life of patients [2] with a risk factor for many diseases, such as type II diabetes [3], cancers [4], and cardiovascular diseases [5]. The composition of the microbiota is recognized to play a role in the pathophysiology of obesity. The colonization of germ-free mice with a gut microbiota harvested from obese mice resulted in an obese phenotype [6]. Other studies highlighted that obese patients or ob/ob mice (a genetic model of obesity) exhibit a dysbiosis with a decrease of the Bacteroidetes/Firmicutes ratio [7,8] and a decrease of the archaea Methanobrevibacter smithii and of the bacteria Escherichia coli (E. coli) [9]

Objectives

Methods

Findings

Conclusion