MicroRNA-494 mediates apoptosis and necrosis in several types of cells, but its renal target and potential role in AKI are unknown. Here, we found that microRNA-494 binds to the 39UTR of activating transcription factor 3 (ATF3) and decreases its transcription. In mice, overexpression of microRNA-494 significantly attenuated the level of ATF3 and induced inflammatory mediators, such as IL-6, monocyte chemotactic protein-1, and P-selectin, after renal ischemia/reperfusion, exacerbating apoptosis and further decreasing renal function. Activation of NF-kB mediated this proinflammatory response. In this ischemia/reperfusion model, urinary levels of microRNA-494 increased significantly before the rise in serum creatinine. In humans, urinary microRNA-494 levels were 60-fold higher in patients with AKI than normal controls. In conclusion, upregulation of microRNA-494 contributes to inflammatory or adhesion molecule-induced kidney injury after ischemia/reperfusion by inhibiting expression of ATF3. Furthermore, microRNA-494 may be a specific and noninvasive biomarker for AKI.

Transcriptional repressor activating transcription factor 3 (ATF3) is induced by various stress stimuli, including inflammation-induced renal injury. In addition, ATF3 also down-regulates adhesion molecules like intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), and monocyte chemotactic protein-1 (MCP-1). However, the relation between up-regulated ATF3 after renal ischemia/reperfusion (I/R) injury and MCP-1 is not completely understood. In this study, we demonstrated that, in renal I/R induced inflammation, induction of adhesion molecules (interleukin-6, P-selectin, E-selectin, ICAM, VCAM, and MCP-1) was higher in ATF3-knockout mice than in wild-type animals. Molecular and biochemical analyses revealed that ATF3 binds to the ATF/CRE sites in the MCP-1 promoter and inhibits the secretion of MCP-1 from renal epithelial cells after I/R injury. Urinary exosome containing ATF3 RNA was 60-fold higher in patients with acute kidney injury than in normal controls, but no difference in total urinary ATF3 RNA levels was found. In addition, in vitro study showed that exosome containing ATF3 RNA derived from epithelial cells also inhibits MCP-1 expression in the epithelial cells and macrophage migration. Furthermore, direct administration of the epithelium-derived exosomal ATF3 RNA attenuates I/R induced kidney injury. Together, our studies reveal a novel regulatory mechanism of MCP-1 expression mediated by the exosomal ATF3 RNA under renal I/R insult and suggest a potential targeted therapy for I/R induced acute kidney injury.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death in Taiwan. In order to delineate the unique demographic features and clinical profile of terminal HCC, we conducted a retrospective study in a hospital-based hospice in Taiwan. Of a total of 991 terminally ill cancer patients (654 men and 337 women, mean age 66.1 years) admitted to our palliative care unit during a three-year period, 110 patients (11.1%) were diagnosed as having HCC (93 men and 17 women, mean age 60.5 years). The most common metastatic sites were bone and lung. Eighty-five HCC patients (77.3%) also had associated liver cirrhosis. The most common symptoms of HCC patients upon admission to the hospice ward were pain, fatigue or weakness, anorexia/vomiting, peripheral edema, cachexia, and ascites. Hypoalbuminemia, anemia, hyponatremia and jaundice were common laboratory abnormalities. Eighty-four patients (76.4%) required opiates for pain management. Upper gastrointestinal bleeding or varices bleeding developed in 76 patients (69.1%). Ninety-four patients (85.5%) died at the hospital, and the overall median survival time at hospice ward was 12 days. Because of more severe underlying portal hypertension and deteriorated liver function, terminal HCC patients with decompensated liver cirrhosis (Child-Pugh class C) had a significantly higher prevalence of peripheral edema, ascites, dyspnea, jaundice, thrombocytopenia, and stage III-IV hepatic encephalopathy than noncirrhotic or Child-Pugh class A and B terminal HCC patients. Symptoms and signs resulting from these portal hypertensions frequently complicated the symptomatic management of terminal HCC patients in the hospice ward. The treatment of these complications is mostly empirical in hospice ward, where intensive laboratory or diagnostic tests are usually not performed. In conclusion, symptoms and signs of terminally ill HCC patients in hospice are unique and should be managed appropriately.