PMID- 21576491
OWN - NLM
STAT- MEDLINE
DCOM- 20110823
LR  - 20211020
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Print)
IS  - 0027-8424 (Linking)
VI  - 108
IP  - 22
DP  - 2011 May 31
TI  - In vivo fluorescence imaging of exogenous enzyme activity in the gastrointestinal 
      tract.
PG  - 9032-7
LID - 10.1073/pnas.1100285108 [doi]
AB  - Exogenous enzymes are administered orally to treat several diseases, such as 
      pancreatic insufficiency and lactose intolerance. Due to the proteinaceous nature 
      of enzymes, they are subject to inactivation and/or digestion in the 
      gastrointestinal (GI) tract. Here we describe a convenient fluorescence-based 
      assay to monitor the activity of therapeutic enzymes in real time in vivo in the 
      GI tract. To establish the proof of principle, the assay was applied to 
      proline-specific endopeptidases (PEPs), a group of enzymes recently proposed as 
      adjuvant therapy for celiac disease (a highly prevalent immunogenetic 
      enteropathy). A short PEP-specific peptide sequence which is part of larger 
      immunotoxic sequences of gluten was labeled with a fluorescent dye and a 
      corresponding quencher. Upon enzymatic cleavage, the fluorescence emission was 
      dequenched and detected with an in vivo imaging system. PEPs originating from 
      Flavobacterium meningosepticum (FM) and Myxococcus xanthus (MX) were evaluated 
      after oral administration in rats. While MX PEP could not cleave the peptide in 
      the stomach, FM PEP showed significant gastric activity reaching 40-60% of the 
      maximal in vivo signal intensity. However, both enzymes produced comparable 
      fluorescence signals in the small intestine. Coadministration of an antacid drug 
      significantly enhanced MX PEP's gastric activity due to increased pH and/or 
      inhibition of stomach proteases. With this simple procedure, differences in the 
      in vivo performance of PEPs, which could not be identified under in vitro 
      conditions, were detected. This imaging assay could be used to study other oral 
      enzymes in vivo and therefore be instrumental in improving their therapeutic 
      efficiency.
FAU - Fuhrmann, Gregor
AU  - Fuhrmann G
AD  - Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical 
      Sciences, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland.
FAU - Leroux, Jean-Christophe
AU  - Leroux JC
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20110516
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Enzymes)
RN  - 0 (Peptides)
RN  - 8002-80-0 (Glutens)
RN  - EC 3.4.21.- (Serine Endopeptidases)
RN  - EC 3.4.21.26 (Prolyl Oligopeptidases)
SB  - IM
EIN - Proc Natl Acad Sci U S A. 2012 Oct 16;109(42):17141
MH  - Anesthesia
MH  - Animals
MH  - Celiac Disease/enzymology
MH  - Chemotherapy, Adjuvant/methods
MH  - Chryseobacterium/metabolism
MH  - Enzymes/chemistry
MH  - Gastrointestinal Tract/*enzymology
MH  - Glutens/chemistry
MH  - Microscopy, Fluorescence/*methods
MH  - Myxococcus xanthus/metabolism
MH  - Peptides/chemistry
MH  - Prolyl Oligopeptidases
MH  - Rats
MH  - Serine Endopeptidases/chemistry
MH  - Stomach/enzymology
MH  - Time Factors
PMC - PMC3107327
COIS- The authors declare no conflict of interest.
EDAT- 2011/05/18 06:00
MHDA- 2011/08/24 06:00
PMCR- 2011/11/30
CRDT- 2011/05/18 06:00
PHST- 2011/05/18 06:00 [entrez]
PHST- 2011/05/18 06:00 [pubmed]
PHST- 2011/08/24 06:00 [medline]
PHST- 2011/11/30 00:00 [pmc-release]
AID - 1100285108 [pii]
AID - 201100285 [pii]
AID - 10.1073/pnas.1100285108 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 2011 May 31;108(22):9032-7. doi: 
      10.1073/pnas.1100285108. Epub 2011 May 16.