title: Designing protease sensors for real-time imaging of trypsin activation in pancreatic cancer cells.
abstract: Acute pancreatitis is a serious and potentially fatal disease caused by intracellular trypsinogen activation. Although protease detection has been greatly facilitated by the development of protease probes capable of monitoring protease activation and inhibition, real-time quantitative measurement of protease activity in living cells remains a challenge, and the identification of the cellular compartment for trypsinogen activation is inconclusive. Here we report a novel strategy for developing trypsin sensors by grafting an enzymatic cleavage site into a sensitive location for optical change of chromophore in a single enhanced green fluorescent protein (EGFP). Our designed trypsin sensor exhibits rapid kinetic responses for protease activation and inhibition with a large ratiometric optical signal change. In addition, it has strong specificity, as enzymatic cleavage is not observed with other proteases such as thrombin, cathepsin B, tryptase, and tissue plasminogen activator. Moreover, the developed trypsin sensor allows us for the first time to observe, in real time, trypsinogen activation by caerulein in the pancreatic cancer cell line, MIA PaCa-2 without zymogen granules. These developed protease sensors will facilitate improved understanding of mechanisms and locations of protease activation and further provide screening of protease inhibitors with therapeutic effects.
authors.affiliation: Department of Chemistry, Center for Drug Design and Biotechnology, Georgia State University, Atlanta, Georgia 30303, USA.
authors.forename: Ning
authors.initials: N
authors.lastname: Chen
authors.forename: Jin
authors.initials: J
authors.lastname: Zou
authors.forename: Siming
authors.initials: S
authors.lastname: Wang
authors.forename: Yiming
authors.initials: Y
authors.lastname: Ye
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gadda
authors.forename: Jenny J
authors.initials: JJ
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D002417:Cattle; D045744:Cell Line, Tumor; D015195:Drug Design; D004789:Enzyme Activation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D015335:Molecular Probes / Q000138:chemical synthesis* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000378:metabolism*; D015202:Protein Engineering; D014357:Trypsin / Q000378:metabolism*
chemical_list: D015335:Molecular Probes; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D010447:Peptide Hydrolases; D014357:Trypsin