Maize (Zea mays L.) contributes approximately 55% of China’s grain production. The effects of nitrogen (N) on maize grain morphology and starch granules remain elusive. In this study, a field experiment in clay loam soil was conducted using three maize hybrids (Suyu 30, Suyu 20, and Suyu 29) and four N levels (0, 360, 450, and 540 kg ha−1) in 2010 and 2012. The results indicated that increased grain length and width, starch granule number, surface area, and volume, was associated with the application of 450 kg ha−1 of N. Differences between superior (ear base) and inferior (apical) grains decreased under highest yield treatments. The effects of N levels on inferior grains was more than that on superior grains. The starch granules of superior grains showed more polygonal, and bigger shape than inferior grains. The results revealed that N levels affected size and morphology of starch granules and grains. The application of 450 kg N ha−1 resulted in larger-sized starch granules and less difference between superior and inferior grains.
Previous studies suggest that activation of SIRT1 protects liver from acetaminophen (APAP)-induced injury; however, the detailed mechanism of SIRT1 modulation in this process is still incomplete. Therefore, this study was to investigate the pathophysiological role of SIRT1 in APAP-mediated hepatotoxicity. We found that SIRT1 mRNA and protein were markedly upregulated in human LO2 cells and mouse liver upon APAP exposure. In vitro, the specific knockdown of SIRT1 expression ultimately aggravated APAP-evoked cellular antioxidant defense in LO2 cells. Moreover, lentivirus-mediated knockdown of hepatic SIRT1 expression exacerbated APAP-induced oxidative stress and liver injury, especially reduction of Nrf2 and subsequent downregulation of several antioxidant genes. Intriguingly, 30 mg/kg SRT1720, the specific SIRT1 activator, which greatly enhanced Nrf2 expression and antioxidant defense, and then eventually reversed APAP-induced hepatic liver injury in mice. Furthermore, APAP responsive miR-19b played an important role in regulating SIRT1 expression, whereas overexpression miR-19b largely abolished the induction of SIRT1 by APAP in vitro and in vivo. Specific SIRT1 3′-UTR mutation, which disrupted the interaction of miRNA-3′UTR, and successfully abrogated the modulation by miR-19b. Notably, hepatic miR-19b overexpression worsened the APAP-induced hepatotoxicity. In general, our results support the notion that the strong elevation of SIRT1 by APAP responsive miR-19b may represent a compensatory mechanism to protect liver against the drug-induced damage, at least in part by enhancing Nrf2-mediated antioxidant capacity in the liver.
Drug-induced liver injury (DILI) is characterized by hepatocyte injury, cholestasis injury, and mixed injury. The liver transplantation is required for serious clinical outcomes such as acute liver failure. Current studies have found that many mechanisms were involved in DILI, such as mitochondrial oxidative stress, apoptosis, necroptosis, autophagy, ferroptosis, etc. Ferroptosis occurs when hepatocytes die from iron-dependent lipid peroxidation and plays a key role in DILI. After entry into the liver, where some drugs or chemicals are metabolized, they convert into hepatotoxic substances, consume reduced glutathione (GSH), and decrease the reductive capacity of GSH-dependent GPX4, leading to redox imbalance in hepatocytes and increase of reactive oxygen species (ROS) and lipid peroxidation level, leading to the undermining of hepatocytes; some drugs facilitated the autophagy of ferritin, orchestrating the increased ion level and ferroptosis. The purpose of this review is to summarize the role of ferroptosis in chemical- or drug-induced liver injury (chemical/DILI) and how natural products inhibit ferroptosis to prevent chemical/DILI.
21 December 2022 in Frontiers in Bioscience-Landmark
Coronary artery disease (CAD) and its main complication, myocardial infarction (MI), is a complex disease caused by environmental and genetic factors and their interaction. Family-based linkage analysis and genome-wide association studies have indicated many of genetic variations related to CAD and MI in recent years. Some are in the coding sequence, which mediates the coding protein, while others are in the non-coding region, which affects the expression of adjacent genes and forms differential gene expression. These variants and differential expressions will have varying degrees of impact on the development of the cardiovascular system and normal heart electrical activity function, subsequently leading to CAD and MI. Among these affected genes, some Transcription Factors (TFs), as important means of transcriptional regulation, have a key role in the pathogenesis of coronary artery disease and myocardial infarction. The GATAs binding protein 2 (GATA2) enhances monocyte adhesion and promoted vessel wall permeabilization through vascular EC adhesion molecule 1 (VCAM-1) upregulation, further revealing its atherosclerosis-promoting role. Myocyte enhancer factor 2 (MEF2) has a role in fostering many functions of the atherosclerotic endothelium and is a potential therapeutic target for atherosclerosis, thrombosis, and inflammation. Nuclear factor-kappa B (NF-κB) is an important promoter of vascular endothelial growth factor (VEGF)-driven angiogenesis, and its pathway has a key role in atherosclerosis-related complications such as angiogenesis, inflammation, apoptosis, and immune effects. Activating transcription factor 3 (ATF3) may be a novel prognostic biomarker and therapeutic target for atherosclerosis. The important role of signal transducer and activator of transcription 3 (STAT3) (especially in mitochondria) in endothelial cells (EC) dysfunction, inflammation, macrophage polarization and immunity in atherosclerosis.