Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.

Mouse models are common tools for examining post-traumatic osteoarthritis (OA), which involves cartilage deterioration following injury or stress. One challenge to current mouse models is longitudinal monitoring of the cartilage deterioration in vivo in the same mouse during an experiment. The objec...

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Main Authors: Sarah E Mailhiot, Donald L Zignego, Justin R Prigge, Ella R Wardwell, Edward E Schmidt, Ronald K June
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2015-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4495059?pdf=render
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author Sarah E Mailhiot
Donald L Zignego
Justin R Prigge
Ella R Wardwell
Edward E Schmidt
Ronald K June
author_facet Sarah E Mailhiot
Donald L Zignego
Justin R Prigge
Ella R Wardwell
Edward E Schmidt
Ronald K June
author_sort Sarah E Mailhiot
collection DOAJ
description Mouse models are common tools for examining post-traumatic osteoarthritis (OA), which involves cartilage deterioration following injury or stress. One challenge to current mouse models is longitudinal monitoring of the cartilage deterioration in vivo in the same mouse during an experiment. The objective of this study was to assess the feasibility for using a novel transgenic mouse for non-invasive quantification of cartilage. Chondrocytes are defined by expression of the matrix protein aggrecan, and we developed a novel mouse containing a reporter luciferase cassette under the inducible control of the endogenous aggrecan promoter. We generated these mice by crossing a Cre-dependent luciferase reporter allele with an aggrecan creERT2 knockin allele. The advantage of this design is that the targeted knockin retains the intact endogenous aggrecan locus and expresses the tamoxifen-inducible CreERT2 protein from a second IRES-driven open reading frame. These mice display bioluminescence in the joints, tail, and trachea, consistent with patterns of aggrecan expression. To evaluate this mouse as a technology for non-invasive quantification of cartilage loss, we characterized the relationship between loss of bioluminescence and loss of cartilage after induction with (i) ex vivo collagenase digestion, (ii) an in vivo OA model utilizing treadmill running, and (iii) age. Ex vivo experiments revealed that collagenase digestion of the femur reduced both luciferase signal intensity and pixel area, demonstrating a link between cartilage degradation and bioluminescence. In an in vivo model of experimental OA, we found decreased bioluminescent signal and pixel area, which correlated with pathological disease. We detected a decrease in both bioluminescent signal intensity and area with natural aging from 2 to 13 months of age. These results indicate that the bioluminescent signal from this mouse may be used as a non-invasive quantitative measure of cartilage. Future studies may use this reporter mouse to advance basic and preclinical studies of murine experimental OA with applications in synovial joint biology, disease pathogenesis, and drug delivery.
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spelling doaj.art-fae141c33624471abc2cab21974907492022-12-22T02:02:10ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01107e013056410.1371/journal.pone.0130564Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.Sarah E MailhiotDonald L ZignegoJustin R PriggeElla R WardwellEdward E SchmidtRonald K JuneMouse models are common tools for examining post-traumatic osteoarthritis (OA), which involves cartilage deterioration following injury or stress. One challenge to current mouse models is longitudinal monitoring of the cartilage deterioration in vivo in the same mouse during an experiment. The objective of this study was to assess the feasibility for using a novel transgenic mouse for non-invasive quantification of cartilage. Chondrocytes are defined by expression of the matrix protein aggrecan, and we developed a novel mouse containing a reporter luciferase cassette under the inducible control of the endogenous aggrecan promoter. We generated these mice by crossing a Cre-dependent luciferase reporter allele with an aggrecan creERT2 knockin allele. The advantage of this design is that the targeted knockin retains the intact endogenous aggrecan locus and expresses the tamoxifen-inducible CreERT2 protein from a second IRES-driven open reading frame. These mice display bioluminescence in the joints, tail, and trachea, consistent with patterns of aggrecan expression. To evaluate this mouse as a technology for non-invasive quantification of cartilage loss, we characterized the relationship between loss of bioluminescence and loss of cartilage after induction with (i) ex vivo collagenase digestion, (ii) an in vivo OA model utilizing treadmill running, and (iii) age. Ex vivo experiments revealed that collagenase digestion of the femur reduced both luciferase signal intensity and pixel area, demonstrating a link between cartilage degradation and bioluminescence. In an in vivo model of experimental OA, we found decreased bioluminescent signal and pixel area, which correlated with pathological disease. We detected a decrease in both bioluminescent signal intensity and area with natural aging from 2 to 13 months of age. These results indicate that the bioluminescent signal from this mouse may be used as a non-invasive quantitative measure of cartilage. Future studies may use this reporter mouse to advance basic and preclinical studies of murine experimental OA with applications in synovial joint biology, disease pathogenesis, and drug delivery.http://europepmc.org/articles/PMC4495059?pdf=render
spellingShingle Sarah E Mailhiot
Donald L Zignego
Justin R Prigge
Ella R Wardwell
Edward E Schmidt
Ronald K June
Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.
PLoS ONE
title Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.
title_full Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.
title_fullStr Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.
title_full_unstemmed Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.
title_short Non-Invasive Quantification of Cartilage Using a Novel In Vivo Bioluminescent Reporter Mouse.
title_sort non invasive quantification of cartilage using a novel in vivo bioluminescent reporter mouse
url http://europepmc.org/articles/PMC4495059?pdf=render
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