To investigate the effect of Irbesartan on the changes of myocardial advanced glycation end products and their receptor (AGEs-RAGE), and matrix metalloproteinases (MMPs) systems in rat type 2 diabetes myocardial fibrosis model. All male Sprague-Dwaley rats were randomly divided into four groups: control (CON), high glucose and high-caloric diet (HC), type 2 diabetes (T2DM) and Irbesartan + T2DM (Ir+T2DM) groups. At 12th week, the fasting blood glucose (FBG) and fasting serum insulin (FINS) levels, insulin resistance index (IRI), insulin sensitivity index (ISI), body weight (BW), the ratio of heart weight/body weight (H/B), left ventricular weight index (LVWI), and cardiac col I, col III contents, plasma MMP-2, MMP-9 levels were evaluated. The protein expressions of col I, AGE, RAGE, MMP-2, MMP-14, and TIMP-2 were analyzed by Western blot. In the T2DM group, FBG, H/B, LVWI, IRI were increased ( P < 0.01), while FINS, BW, ISI were decreased in contrast to the CON and HC groups ( P < 0.05–0.01). In the Ir+ T2DM group, BW was higher, IRI, H/B, LVWI were lower than in the T2DM group. Compared with the CON and HC groups, the contents of col I and col III, the protein expressions of col I, AGE, RAGE, TIMP-2 and MMP-14 were increased, MMP-2 protein expression, the ratios of MMP-2/TIMP-2 and MMP-14/TIMP-2, MMP-2, and MMP-9 levels were decreased in the T2DM group ( P < 0.01). After Irbesartan treatment, all parameters were reversed. Irbesartan can ameliorate myocardial fibrosis in type 2 diabetes rat model, the likely mechanisms may be related to the down-regulation of AGEs-RAGE system and changes of MMPs pathway. Impact statement: There are about 425 million diabetes patients (20–79 years) in the world according to the International Diabetes Federation Diabetes Atlas – 8th Edition. The cardiovascular complication is one of the major causes of death in diabetes patients. Myocardial fibrosis is one of the serious pathological changes, so investigating the pathogenesis of myocardial fibrosis has the significant value. Our study aims to investigate the effect of Irbesartan (the angiotensin II receptor antagonist) on the changes of AGE-RAGE system and MMP family components, and analyzes the potential mechanisms in type 2 diabetes-induced myocardial fibrosis. Our results provide the theoretical base for better understanding the pathogenesis in type 2 diabetes-induced myocardial complication. It is useful for clinicians to select the effective therapeutic measures for treatment of type 2 diabetes-induced organ fibrosis.

Liver plays a key role in sepsis, a systemic inflammatory response syndrome caused by infection. Ferroptosis is involved in sepsis-induced liver injury. We aimed to assess the changes in ferroptosis in cecal ligation and puncture (CLP)-induced septic mice, and determine the role of lipocalin-2 (LCN2) in liver ferroptosis. CLP was used to induce sepsis in mice. The morphological changes in liver tissues and mitochondrial structure were observed using hematoxylin and eosin staining and transmission electron microscopy. The levels of serum alanine transaminase, aspartate aminotransferase, superoxide dismutase, and malondialdehyde were detected using the corresponding kits. The changes of reactive oxygen species level in liver tissues were detected using dihydroethidium as a fluorescence probe. LCN2, cysteine-glutamate reverse transport system, and dihydroorotate dehydrogenase protein levels in the liver were detected by western blotting. The ferroptosis inhibitor ferrostatin-1 (Fer-1), iron chelator dexrazoxane (DXZ), iron-dextran, and LCN2 knockdown studies were performed to determine role of ferroptosis and LCN2 in liver injury during sepsis. Ferroptosis levels increased in the liver tissues of CLP-induced septic mice. Both Fer-1 and DXZ suppressed ferroptosis and attenuated liver injury following sepsis challenge, whereas iron-dextran increased ferroptosis and liver injury in mice with sepsis. LCN2 knockdown suppressed ferroptosis and reduced oxidative stress in the liver. Ferroptosis inhibition attenuates septic liver injury. LCN2 knockdown alleviates sepsis-induced liver injury by inhibiting ferroptosis and reducing oxidative stress.

Background: Ferroptosis and long-noncoding RNAs (lncRNAs) play crucial roles in doxorubicin (DOX)-induced myocardial injury (DIMI). Nevertheless, there is no research to construct competing endogenous RNAs (ceRNAs) network between lncRNAs and ferroptosis-related key gene. So our research was designed to screen ferroptosis-related genes from differentially expressed mRNAs in DIMI and construct lncRNAs regulated ferroptosis-related key gene ceRNAs network. Methods: The male mice were injected with DOX intraperitoneally to induce myocardial injury, myocardial injury was evaluated by hematoxylin and eosin (HE) staining, and ferroptosis-related protein-glutathione peroxidase 4 (GPx4) protein expression was detected. The differentially expressed lncRNAs and mRNAs were detected by microarray, and the ferroptosis-related genes were screened to construct a protein-protein associations (PPA) network, the highest maximal clique centrality (MCC) score gene were identified by Cytoscape software, miRNAs bound to key genes and lncRNAs bound to miRNAs were predicted; then, the obtained lncRNAs were intersected with differentially expressed lncRNAs detected by microarray. Finally, the lncRNA/miRNA/mRNA ceRNA network of the highest MCC score gene regulating ferroptosis in DIMI was constructed. The expressions of the key components in ceRNA network were detected by qRT-PCR. Results: Compared with the control group, in the DOX group, myocardial enzymes and HE staining showed that myocardium structure was changed, and GPx4 protein expression was decreased. The differentially expressed 10,265 lncRNAs and 6,610 mRNAs in the DOX group were detected via microarray. Among them, 114 ferroptosis-related genes were obtained to construct PPA networks, and Becn1 was identified as the key gene. Finally, the ceRNA network including Becn1, three miRNAs and four lncRNAs was constructed by predicting data of the Starbase database. The relative expressions of these components in ceRNA net were up-regulated and consistent with microarray results. Conclusions: Based on the microarray detection results and bioinformatics analysis, we screened ferroptosis-related gene Becn1 and constructed the lncRNA/miRNA/mRNA ceRNA network of regulated ferroptosis in DIMI.

Ferroptosis is a form of regulated cell death (RCD) characterized by accumulation of lipid peroxides and dependence on iron. However, the role of ferroptosis in sepsis-induced myocardial injury remains unclear. Results Here, we used the cecal ligation and puncture (CLP) model to induce the onset of myocardial injury in sepsis mice, and established an iron overload model as positive control group to explore the specific effects of iron overload on myocardium and explore the mechanism of sepsis induced myocardial injury. The results showed that in the CLP group, the levels of myocardial injury markers --- cardiac troponin T (CTn-T), myocardial-bound creatine kinase (CK-MB), lactic dehydrogenase (LDH) were elevated, the levels of oxidative stress markers ---- malondialdehyde (MDA) and reactive oxygen species (ROS) levels were increased, the levels of the antioxidant enzymes superoxide dismutase (SOD) and the anti-ferroptosis markers ---- glutathione peroxidase 4 (GPX4), the solute carrier family-7 member-11 (SLC7A11/ xCT), ferroptosis suppressor protein-1(FSP1), and lipin-1 (LPIN1) were decreased, lipocalin 2 (Lcn2) protein expression and signal transducer and activator of transcription 3 (STAT3) phosphorylation were increased, mitochondria damage was observed when compared with the sham group. All above results were attenuated by ferrostatin-1 (Fer-1, a ferroptosis inhibitor) and dexrazoxane hydrochloride (DXZ, an iron chelator). Meanwhile, acute iron overload injury caused by iron dextran was consistent with the CLP group. We also found Transferrin Receptor1 (TFR1) protein expression was increased and the expressions of ferritin and ferroprotein 1 (FPN1) proteins were decreased in the CLP and iron dextran groups in contrast to the control group, indicating accumulation of intracellular iron occurred in the CLP and iron dextran groups. Based on these findings, we concluded that iron overload and ferroptosis are maybe the key mechanisms underlying CLP-induced myocardial injury in septic mice. STAT3/Lcn2 may involve in regulating iron overload and ferroptosis, and performs as a potential therapy target in sepsis-induced myocardial injury.