Cryptosporidiosis induces a transient upregulation of the oligopeptides transporter (PepT1) activity in neonatal rats.
Cryptosporidium parvum is a parasitic protozoa increasingly appreciated as a cause of intestinal malabsorptive syndrome leading to malnutrition and/or growth failure. Because a major mechanism for apical peptide absorption by small intestine is via the proton-coupled transporter PepT1, we investigated the expression and functionality of this transporter in our model of acute cryptosporidiosis. Four-day-old Sprague-Dawley rats were inoculated by gavage with 5 x 10(5) oocysts of C. parvum and killed at Day 12 (peak of the infection) or Day 21 (spontaneous clearance of the parasite). PepT1 expression and functionality were quantified in the distal small intestine, preferential site of C. parvum implantation, and in the proximal small intestine, free of parasite, using Western blot and Ussing chambers, respectively. No difference in total PepT1 protein expression or in glycyl-sarcosine fluxes was observed in C. parvum-infected rats compared with controls either on Day 12 or on Day 21, both in the proximal and in the distal small intestine. However, a significant decrease of apical membrane protein expression of PepT1 was observed in C. parvum-infected enterocytes compared with controls. This maintained dipeptide transport observed despite villous atrophy and decreased expression of the protein at the brush-border membrane strongly suggest a transient upregulation of PepT1 activity, probably related to gamma-interferon regulation.
Marquet
Perrine
P
EA209 Eucaryotes Pathogènes, Faculté des Sciences Pharmaceutiques et Biologiques, Université René Descartes, 75006 Paris, France.
Barbot
Laurence
L
Planté
Aurélia
A
Huneau
Jean François
JF
Gobert
Jean Gérard
JG
Kapel
Nathalie
N
D000818:Animals; D000833:Animals, Suckling; D015153:Blotting, Western; D003457:Cryptosporidiosis / Q000097:blood / Q000378:metabolism* / Q000469:parasitology; D016785:Cryptosporidium parvum / Q000254:growth & development*; D004151:Dipeptides / Q000378:metabolism; D020895:Enterocytes / Q000378:metabolism / Q000469:parasitology; D007082:Ileum / Q000378:metabolism / Q000469:parasitology; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism / Q000469:parasitology; D008871:Microvilli / Q000378:metabolism / Q000469:parasitology; D000074011:Peptide Transporter 1; D051381:Rats; D017207:Rats, Sprague-Dawley; D027981:Symporters / Q000378:metabolism*; D015854:Up-Regulation
D004151:Dipeptides; D000074011:Peptide Transporter 1; C489940:Slc15a1 protein, rat; D027981:Symporters; C004194:glycylsarcosine; D007371:Interferon-gamma