ZBP1 promotes hepatocyte pyroptosis in acute liver injury by regulating the PGAM5/ROS pathway.

INTRODUCTION AND OBJECTIVES: Acute liver injury (ALI) is characterized by massive hepatocyte death with high mortality and poor prognosis. Hepatocyte pyroptosis plays a key role in the physiopathological processes of ALI, which can damage mitochondria and release NLRP3 inflammasome particles, causing systemic inflammatory responses. Z-DNA Binding Protein 1 (ZBP1) is a sensor that induces cell death. Here, we investigated whether ZBP1 participates in hepatocyte pyroptosis and explored the possible pathogenesis of ALI. MATERIALS AND METHODS: Hepatocyte pyrotosis was induced with lipopolysaccharide (LPS) and nigericin (Nig), and the expression of Zbp1 (ZBP1) was examined by western blot analysis and RT-qPCR. Further, we transfected AML-12 (LO2 and HepG2) cell lines with Zbp1 (ZBP1) siRNA. After ZBP1 was silenced, LDH release and flow cytometry were used to measure the cell death; Western blot analysis and RT-qPCR were used to detect the marker of NLRP3 inflammasome activation and pyroptosis. We also detected the expression of mitochondrial linear rupture marker phosphoglycerate mutase family member 5 (PGAM5) using western blot analysis and reactive oxygen species (ROS) using the DCFH-DA method. RESULTS: The expression of ZBP1 was up-regulated in LPS/Nig-induced hepatocytes. Si-Zbp1 (Si-ZBP1) inhibited NLRP3 inflammasome activation and pyroptosis in LPS/Nig-induced hepatocytes. Moreover, ZBP1 silencing inhibited the expression of PGAM5 by reducing ROS production. CONCLUSIONS: ZBP1 promotes hepatocellular pyroptosis by modulating mitochondrial damage, which facilitates the extracellular release of ROS.

Pregnancy and COVID-19: management and challenges.

The consequences of COVID-19 infecting pregnant women and the potential risks of vertical transmission have become a major issue. Since little is currently known about COVID-19 in pregnancy, the understanding of COVID-19 in this particular group will be updated in time, and a comprehensive review will be useful to evaluate the impact of COVID-19 in pregnancy. Based on recently published literature and official documents, this review provides an introduction to the pathogenesis, pathology, and clinical features of COVID-19 and has focused on the current researches on clinical features, pregnancy outcomes and placental histopathological analysis from pregnant women infected with SARS-CoV-2 in comparison with SARS-CoV and MERS-CoV. These viruses trigger a cytokine storm in the body, produce a series of immune responses, and cause changes in peripheral leukocytes and immune system cells leading to pregnancy complications that may be associated with viral infections. The expression of ACE2 receptors in the vascular endothelium may explain the histological changes of placentas from pregnant women infected by SARS-CoV-2. Pregnant women with COVID-19 pneumonia show similar clinical characteristics compared with non-pregnant counterparts. Although there is no unequivocal evidence to support the fetal infection by intrauterine vertical transmission of SARS, MERS and SARS-CoV-2 so far, more and more articles began to report maternal deaths due to COVID-19. In particular, from February 26, 2020 (date of the first COVID-19 case reported in Brazil) until June 18, 2020, Brazil reported 124 maternal deaths. Therefore, pregnant women and neonates require special attention regarding the prevention, diagnosis and management of COVID-19.