PGD 2 /DP1 axis promotes liver regeneration by secreting Wnt2 in KCs in mice.

ABSTRACT

BACKGROUND AND AIMS: The liver possesses a remarkable regenerative capacity in response to injuries or viral infections. Various growth factors and cytokines are involved in regulating liver regeneration. Prostaglandin D 2 , a pro-resolution lipid mediator, is the most abundant hepatic prostanoid. However, the role of prostaglandin D 2 in the injury-induced liver regeneration remains unclear. APPROACH AND RESULTS: Two-thirds partial hepatectomy (70% PH), massive hepatectomy (85% resection), and carbon tetrachloride-induced chronic injury were performed in mice to study the mechanisms of live regeneration. Hepatic prostaglandin D 2 production was elevated in mice after PH. Global deletion of D prostanoid receptor (DP) 1, but not DP2, slowed PH-induced liver regeneration in mice, as evidenced by lower liver weight to body weight ratio, less Ki67 + hepatocyte proliferation, and G2/M phase hepatocytes. In addition, DP1 deficiency, specifically in resident KCs, and not in endothelial cells or HSCs, retarded liver regeneration in mice after PH. Conversely, the overexpression of exogenous DP1 in KCs accelerated liver regeneration in mice. Mechanistically, DP1 activation promoted Wnt2 transcription in a PKA/CREB-dependent manner in resident KCs and mediated hepatocyte proliferation through Frizzled8/ß-catenin signaling. Adeno-associated virus vector serotype 8-mediated Frizzled8 knockdown in hepatocytes attenuated accelerated liver regeneration in KC-DP1 transgenic mice after PH. Treatment with the DP1 receptor agonist BW245C promotes PH-induced liver regeneration in mice. CONCLUSIONS: DP1 activation mediates crosstalk between KCs and hepatocytes through Wnt2 and facilitates liver regeneration. Hence, DP1 may serve as a novel therapeutic target in acute and chronic liver diseases.