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Toxins (Basel). 2018 Sep 1;10(9). pii: E351. doi: 10.3390/toxins10090351.

Enterohemorrhagic E. coli (EHEC)-Secreted Serine Protease EspP Stimulates Electrogenic Ion Transport in Human Colonoid Monolayers.

Author information

1
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. mtse@jhmi.edu.
2
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. jgin@salud.unm.edu.
3
Department of Internal Medicine, Division of Gastroenterology & Hepatology, University of New Mexico, Albuquerque, NM 87131, USA. jgin@salud.unm.edu.
4
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. jianyi.yin@outlook.com.
5
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. mdonowit@jhmi.edu.
6
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. mdoucet2@jhmi.edu.
7
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. jfoulke@jhmi.edu.
8
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. FR3D@hscmail.mcc.virginia.edu.
9
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. JPN2R@hscmail.mcc.virginia.edu.
10
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. nzachos1@jhmi.edu.
11
Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA. JKaper@som.umaryland.edu.
12
Department of Medicine, Division of Gastroenterology & Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. OKovbasnjuk@salud.unm.edu.
13
Department of Internal Medicine, Division of Gastroenterology & Hepatology, University of New Mexico, Albuquerque, NM 87131, USA. OKovbasnjuk@salud.unm.edu.

Abstract

One of the characteristic manifestations of Shiga-toxin-producing Escherichia coli (E. coli) infection in humans, including EHEC and Enteroaggregative E. coli O104:H4, is watery diarrhea. However, neither Shiga toxin nor numerous components of the type-3 secretion system have been found to independently elicit fluid secretion. We used the adult stem-cell-derived human colonoid monolayers (HCM) to test whether EHEC-secreted extracellular serine protease P (EspP), a member of the serine protease family broadly expressed by diarrheagenic E. coli can act as an enterotoxin. We applied the Ussing chamber/voltage clamp technique to determine whether EspP stimulates electrogenic ion transport indicated by a change in short-circuit current (Isc). EspP stimulates Isc in HCM. The EspP-stimulated Isc does not require protease activity, is not cystic fibrosis transmembrane conductance regulator (CFTR)-mediated, but is partially Ca2+-dependent. EspP neutralization with a specific antibody reduces its potency in stimulating Isc. Serine Protease A, secreted by Enteroaggregative E. coli, also stimulates Isc in HCM, but this current is CFTR-dependent. In conclusion, EspP stimulates colonic CFTR-independent active ion transport and may be involved in the pathophysiology of EHEC diarrhea. Serine protease toxins from E. coli pathogens appear to serve as enterotoxins, potentially significantly contributing to watery diarrhea.

KEYWORDS:

CFTR; EHEC; SPATEs; diarrhea; human colonoid monolayers; intracellular Ca2+; serine protease EspP; short circuit current

PMID:
30200426
PMCID:
PMC6162544
DOI:
10.3390/toxins10090351
[Indexed for MEDLINE]
Free PMC Article

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