Generating mouse models of degenerative diseases using Cre/lox-mediated in vivo mosaic cell ablation
Masato Fujioka, … , Hideyuki Okano, Albert S.B. Edge
Masato Fujioka, … , Hideyuki Okano, Albert S.B. Edge
Published May 16, 2011
Citation Information: J Clin Invest. 2011;121(6):2462-2469. https://doi.org/10.1172/JCI45081.
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Generating mouse models of degenerative diseases using Cre/lox-mediated in vivo mosaic cell ablation

Abstract

Most degenerative diseases begin with a gradual loss of specific cell types before reaching a threshold for symptomatic onset. However, the endogenous regenerative capacities of different tissues are difficult to study, because of the limitations of models for early stages of cell loss. Therefore, we generated a transgenic mouse line (Mos-iCsp3) in which a lox-mismatched Cre/lox cassette can be activated to produce a drug-regulated dimerizable caspase-3. Tissue-restricted Cre expression yielded stochastic Casp3 expression, randomly ablating a subset of specific cell types in a defined domain. The limited and mosaic cell loss led to distinct responses in 3 different tissues targeted using respective Cre mice: reversible, impaired glucose tolerance with normoglycemia in pancreatic β cells; wound healing and irreversible hair loss in the skin; and permanent moderate deafness due to the loss of auditory hair cells in the inner ear. These mice will be important for assessing the repair capacities of tissues and the potential effectiveness of new regenerative therapies.

Authors

Masato Fujioka, Hisashi Tokano, Keiko Shiina Fujioka, Hideyuki Okano, Albert S.B. Edge

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Figure 1

Mosaic ablation of pancreatic β cells led to impaired glucose tolerance.

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Mosaic ablation of pancreatic β cells led to impaired glucose tolerance....
(A) Plan for the cell ablation experiments. (B) Experimental design for mosaic ablation of pancreatic β cells using a double-transgenic Ins2-Cre;Mos-iCsp3 mouse. BS, blood sugar; ipGTT, i.p. glucose tolerance test. (C) Time course of fasting blood sugar in double transgenics (Cre/Csp) and littermate controls. There were no significant differences in the fasting blood sugar in 2 groups at any time point. (D and E) Glucose tolerance test of (E) double-transgenic mice and (D) littermate controls. Blood sugar was elevated in double transgenics only after intraperitoneal glucose injection (1 mg/g body weight) compared with that in littermates after AP20187 treatment, while there were no differences before dimerizer treatment. Note that the glucose level was highly elevated in wild-type mice treated with streptozotocin (Stz), both fasting and after glucose loading. (F) Fasting blood sugar level and glucose tolerance test 15 minutes after loading. (G) Gross histology of pancreatic β cells in double transgenics. Many islet cells had pyknotic nuclei in a mosaic distribution at day 10 (black arrows), suggesting that dimerizer had induced stochastic apoptosis of β cells. Note that no apoptotic cells were found, but the size of the islet was larger at day 40 than that in pretreatment, which is consistent with other reported models for specific β cell ablation. Scale bar: 20 μm. (H) Quantification of the insulin immunopositive area at different time points. A significant decrease in the insulin-positive area was observed at day 10 compared with that in pre-AP20187–treated control double transgenics. *P < 0.05, **P < 0.01.