ADP-ribosylation is a reversible reaction with
ADP-ribosyltransferases catalyzing the forward reaction and
ADP-ribose-acceptor
hydrolases (ARHs) hydrolyzing the
ADP-ribose acceptor bond. ARH2 is a member of the 39-kDa ARH family (ARH1-3), which is expressed in heart and skeletal muscle. ARH2 failed to exhibit any in vitro enzymatic activity. To determine its possible in vivo activities, Arh2 -knockout (KO) and - heterozygous (Het) mice were generated using CRISPR-Cas9. Arh2 -KO mice exhibited decreased cardiac contractility by MRI, echocardiography and
dobutamine stress with
cardiomegaly and abnormal motor function. Arh2 -Het mice showed results similar to those seen in Arh2 -KO mice except for
cardiomegaly. Arh2 -KO and -Het mice and mouse embryonic fibroblasts (MEFs) developed spontaneous
tumors and subcutaneous
tumors in nude mice. We identified 13 mutations in Arh2 -Het MEFs and heterozygous
tumors, corresponding to human ARH2 mutations in
cancers obtained from COSMIC. Of interest, the L116R mutation in Arh2 gene plays a critical role in aggressive
tumorigenesis in nude mice, corresponding to human ARH2 mutations in stomach
adenocarcinoma. Both genders of Arh2 -KO and -Het mice showed increased unexpectedly deaths and decreased survival rate during a 24-month observation, caused by
tumor,
inflammation, non-
inflammation (e.g.,
cardiomegaly, dental dysplasia), and congenital diseases. Thus, Arh2 plays a pivotal role in cardiac function,
tumorigenesis,
inflammation, and overall survival.