Generation, Validation and Characterization of IntL-Piezo1-/- mice
(A) Schematic description for the generation of Villin-Flippase (Vil-Flp) and Flippase-dependent Gcg-Cre (FGC) mice. Vil-Flp flip the inverted Cre gene in the Gcg-Cre cassette in IntL-Cre mice to restrict Cre expression in intestinal L cells. As shown, Locations of genotyping primers are also indicated.
(B) Tail DNA genotyping PCR results using genotyping primer for Vil-Flp, FGC and Flippase-activated Cre (IntL-Cre) mice.
(C) Intestine and pancreas DNA genotyping results. The “Original” band represents the original FGC cassette with inverted Cre, while the “Flipped” band represents recombined FGC cassette with Cre flipped into the correct direction.
(D) Schematic description for the validation of IntL-Cre efficacy by crossing with mT/mG reporter mice.
(E) Fluorescence was detected in the ileal and pancreatic tissues from mT/mG and IntL-Cre-mT/mG mice by frozen tissue confocal microscopy. Green fluorescence represents successful deletion of TdTomato and reactivation of EGFP in the Cre-expressing cells.
(F) Schematic description for the generation of Intestinal L cell-Piezo1-/- mice (IntL-Piezo1-/-) by crossing Piezo1loxp/loxp mice with IntL-Cre mice.
(G) Body weight of 14- to 16-week-old male mice of the indicated genotypes fed NCD (n=6/group)
(H-I) IPGTT (H) and ITT (I) and associated area under the curve (AUC) values of 14- to 16-week-old male mice of the indicated genotypes fed NCD (n=6/group).
(J) Proglucagon mRNA levels in ileum of 14- to 16-week-old male mice of the indicated genotypes fed NCD. (n=6/group).
(K) The plasma GLP-1 levels in 14- to 16-week-old male mice of the indicated genotypes fed NCD (n=6/group).
(L) Representative images for Piezo1 RNA-FISH and GLP-1 immunofluorescent staining in the ileum of 14-week-old male mice of indicated genotypes fed NCD (n=6/group).
(M) Percentage of Piezo1-positive GLP-1 cells in total GLP-1 cells in the ileal mucosa of 14-week-old male mice of indicated genotypes fed NCD (n=6/group).
(N) A schematic diagram depicting the potential mechanisms linking the CaMKKβ/CaMKIV-mTOR signaling pathway and GLP-1 production.
(O) Representative western blots are shown for indicated antibodies in the ileal mucosa (n = 6/group).
Data are represented as mean ± SEM. Significance was determined by Student’s t test for comparison between two groups, and by one-way ANOVA for comparison among three groups or more, *p < 0.05, **p < 0.01, ***p < 0.001.