Systemic overexpression of TNFα-converting enzyme does not lead to enhanced shedding activity in vivo.
TNFα-converting enzyme (TACE/ADAM17) is a membrane-bound proteolytic enzyme with a diverse set of target molecules. Most importantly, TACE is indispensable for the release and activation of pro-TNFα and the ligands for epidermal growth factor receptor in vivo. Previous studies suggested that the overproduction of TACE is causally related to the pathogenesis of inflammatory diseases and cancers. To test this hypothesis, we generated a transgenic line in which the transcription of exogenous Tace is driven by a CAG promoter. The Tace-transgenic mice were viable and exhibited no overt defects, and the quantitative RT-PCR and Western blot analyses confirmed that the transgenically introduced Tace gene was highly expressed in all of the tissues examined. The Tace-transgenic mice were further crossed with Tace⁻/⁺ mice to abrogate the endogenous TACE expression, and the Tace-transgenic mice lacking endogenous Tace gene were also viable without any apparent defects. Furthermore, there was no difference in the serum TNFα levels after lipopolysaccharide injection between the transgenic mice and control littermates. These observations indicate that TACE activity is not necessarily dependent on transcriptional regulation and that excess TACE does not necessarily result in aberrant proteolytic activity in vivo.
Anti-aging Orthopedic Research, School of Medicine, Keio University, Tokyo, Japan.
Masaki
M
Yoda
Tokuhiro
T
Kimura
Takahide
T
Tohmonda
Hideo
H
Morioka
Morio
M
Matsumoto
Yasunori
Y
Okada
Yoshiaki
Y
Toyama
Keisuke
K
Horiuchi
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000072198:ADAM17 Protein; D000818:Animals; D015153:Blotting, Western; D051379:Mice; D008822:Mice, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012772:Shock, Septic; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606463:Adam17 protein, mouse