1. Vascular Endothelial-Specific Dimethylarginine Dimethylaminohydrolase-1–Deficient Mice Reveal That Vascular Endothelium Plays an Important Role in Removing Asymmetric Dimethylarginine
by Xinli Hu, Xin Xu, Guangshuo Zhu, Dorothee Atzler, Masumi Kimoto, Ju Chen, Edzard Schwedhelm, Nicole Lüneburg, Rainer H. Böger, Ping Zhang, and Yingjie Chen
Circulation
Volume 120(22):
December 1, 2009
Copyright © American Heart Association, Inc. All rights reserved.

2. Figure 1. Generation of endo-DDAH1−/− mice.
Figure 1. Generation of endo-DDAH1−/− mice. A, Targeting strategy. A restriction map of the relevant genomic DNA of DDAH1 gene, the targeting vector, the targeted locus after recombination, and the exon 4 deleted locus is shown. neo indicates neomycin resistance gene; arrowheads, LoxP sites; R, EcoRI; B, BamHI; and X, XhoI. B, Southern blot of wild-type and targeted alleles. Genomic DNA was prepared from embryonic stem (ES) cell and mice and digested with EcoRI. The 12-kb and 8.5-kb bands represent wild-type and targeted allele, respectively. C, Genotyping by PCR with the use of primer pair H1 and H17 (as indicated in A). The PCR products were 0.7, 1.3, and 1.8 kb for the wild-type, the exon 4 deleted allele, and the exon 4 floxed allele, respectively.
Xinli Hu et al. Circulation. 2009;120:
Copyright © American Heart Association, Inc. All rights reserved.

3. Figure 2. Expression of DDAH1 and DDAH2 in endothelial-specific DDAH1 knockout mice.
Figure 2. Expression of DDAH1 and DDAH2 in endothelial-specific DDAH1 knockout mice. To show the relative decrease of DDAH1 expression in various organs of the endo-DDAH1−/− mice, different amounts of total tissue lysate were loaded for different organs, and the exposure times of different Western blots were varied (A). The protein levels of DDAH2 were not changed in heart, lung, and kidney in the endo-DDAH1−/− mice (B). −/− indicates homozygote for endothelial-specific DDAH1 knockout mice (endo-DDAH1−/−); +/−, heterozygote for endothelial-specific DDAH1 knockout mice (endo-DDAH1+/−); C1, wild-type control mice, with Tie2-Cre expression; and C2, DDAH1flox/flox control mice.
Xinli Hu et al. Circulation. 2009;120:
Copyright © American Heart Association, Inc. All rights reserved.

4. Figure 3. Endothelial-specific DDAH1 knockout led to increased ADMA level in plasma (A) (n=9 samples in each group), as well as in kidney, lung, and liver (B) (n=4 to 5 samples in each group).
Figure 3. Endothelial-specific DDAH1 knockout led to increased ADMA level in plasma (A) (n=9 samples in each group), as well as in kidney, lung, and liver (B) (n=4 to 5 samples in each group). In the DDAH1−/− mice, the SDMA level was not changed in lung and kidney but was significantly increased in the liver (C) (n=4 to 5 samples in each group). The endo-DDAH1−/− aortic rings had reduced acetylcholine (Ach)-induced NO generation (D) (n=6 to 8 samples in each group) and acetylcholine-induced vessel relaxation (E), but relaxation in response to sodium nitroprusside (SNP) was not affected (F) (n=7 to 10 samples for each condition). WT indicates wild-type; KO, knockout. P<0.05 as compared with DDAH1flox/flox controls.
Xinli Hu et al. Circulation. 2009;120:
Copyright © American Heart Association, Inc. All rights reserved.

5. Figure 4. The endo-DDAH1−/− mice had increased tail blood pressure (A), systolic LV pressure (B), and mean aortic pressure (C D).
Figure 4. The endo-DDAH1−/− mice had increased tail blood pressure (A), systolic LV pressure (B), and mean aortic pressure (C D). Representative aortic and LV pressure recordings are shown (D). *P<0.05 compared with DDAH1flox/flox controls. Mean value was obtained from 8 to 10 samples in each group.
Xinli Hu et al. Circulation. 2009;120:
Copyright © American Heart Association, Inc. All rights reserved.