Background:Without adequate treatment, pathological cardiac hypertrophy induced by sustained pressure overload eventually leads to HF (HF). WW domain- containing E3 ubiquitin protein ligase 1 (WWP1) is an important regulator of aging-related pathologies, including cancer and cardiovascular diseases. However, the role of WWP1 in pressure overload-induced cardiac remodeling and HF is yet to be determined.Methods:To examine the correlation of WWP1 with hypertrophy, we analyzed WWP1 expression in patients with HF and mice subjected to transverse aortic constriction (TAC) by Western blotting and immunohistochemical staining. TAC surgery was performed on WWP1 knockout (KO) mice to assess the role of WWP1 in cardiac hypertrophy, heart function was examined by echocardiography and related cellular and molecular markers were examined. Mass spectrometry and coimmunoprecipitation assays were conducted to identify the proteins that interacted with WWP1. Pulse-chase assay, ubiquitination assay, reporter gene assay and anin vivomouse model via adeno-associated virus serotype 9 (AAV9) were used to explore the mechanisms by which WWP1 regulates cardiac remodeling. AAV9 carrying cTnT promoter driven small hairpin RNA targeting WWP1 (AAV9-cTnT-shWWP1) was administered to investigate its rescue role in TAC-induced cardiac dysfunction.Results:The WWP1 level was significantly increased in the hypertrophic hearts from patients with HF and mice subjected to TAC. The results of echocardiography and histology demonstrated that WWP1 KO protected the heart from TAC-induced hypertrophy. There was a direct interaction between WWP1 and disheveled segment polarity protein 2 (DVL2). DVL2 was stabilized by WWP1 mediated K27-linked polyubiquitination. The role of WWP1 in pressure overload-induced cardiac hypertrophy was mediated by the DVL2/CaMKII/HDAC4/MEF2C signaling pathway. Therapeutic targeting WWP1 almost abolished TAC induced heart dysfunction, suggesting WWP1 as a potential target for treating cardiac hypertrophy and failure.Conclusions:We identified WWP1 as a key therapeutic target for pressure overload induced cardiac remodeling. We also found a novel mechanism regulated by WWP1. WWP1 promotes atypical K27-linked ubiquitin multichain assembly on DVL2 and exacerbates cardiac hypertrophy by the DVL2/CaMKII/HDAC4/MEF2C pathway.