ObjectiveTo summarize the research advances of pyroptosis in hepatic ischamia-reperfusion injury (IRI).MethodThe literatures about the studies of mechanism of pyroptosis in hepatic IRI were retrieved and analyzed.ResultsPyroptosis, also known as inflammatory necrocytosis, was proven to play an important role in the hepatic IRI. When hepatic ischemia-reperfusion occurred, the classical pathway of pyroptosis dependenting on caspase-1 and the non-classical pathway of pyroptosis dependenting on caspase-11 were initiated by specific stimulants, and leaded to the activation of gasdermin D, releases of proinflammatory factors such as interleukin-1β, interleukin-18, etc., and the recruitment and activation of neutrophils. Consequently, pyroptosis caused more severe hepatic inflammation and aggravated existing cell injury and dysfunction of liver during hepatic IRI.ConclusionsPyroptosis plays an important role in liver IRI. Further researches about mechanism of pyroptosis will be beneficial to the prevention and treatment of the pyroptosis of related diseases.
Pyroptosis is an inflammatory form of programmed cell death, including canonical and non-canonical pyroptosis pathway. Studies on pyroptosis have been reported in a variety of retinal diseases, but they are more focused on common diseases such as diabetic retinopathy and age-related macular degeneration. Many retinal diseases are difficult to treat because of the complexity of their etiology and pathogenesis. The discovery of pyroptosis has brought new content to the pathogenesis of these diseases, and also pointed a new direction for the treatment. Pyroptosis does not occur independently, and it is related to apoptosis and autophagy, but the specific mechanism is not clear. However, the most important biomolecule in the process of pyroptosis have been basically determined, and some methods can be used to interfere with pyroptosis, which has obtained preliminary achievement, suggesting that inhibition of pyroptosis may be a new direction for the treatment of retinal diseases and has broad research prospects.
Objective To observe the effect of metformin (Met) on inflammatory bodies and focal death in human retinal microvascular endothelial cells (hRMEC) in diabetes mellitus (DM) microenvironment. MethodsExperimental research was divided into in vivo animal experiment and in vitro cell experiment. In vivo animal experiments: 9 healthy C57BL/6J male mice were randomly divided into DM group, normal control group, and DM+Met group, with 3 mice in each group. DM group and DM+Met group mice were induced by streptozotocin to establish DM model, and DM+Met group was given Met 400 mg/ (kg · d) intervention. Eight weeks after modeling, the expression of NLRP3, cleaved-membrane perforating protein D (GSDMD) and cleaved-Caspase-1 in the retina of mice in the normal control group, DM group and DM+Met group were observed by immunohistochemical staining. In vitro cell experiments: hRMEC was divided into conventional culture cell group (N group), advanced glycation end products (AGE) group, and AGE+Met group. Joining the AGE, AGE+Met groups cells were induced by 150 μg/ml of glycation end products, and 2.0 mmol/L Met was added to the AGE+Met group. Pyroptosis was detected by flow cytometry; 2',7'-dichlorofluorescein diacetate (DCFH-DA) fluorescent probe was used to detect the expression of reactive oxygen species (ROS) in cells of each group. Real-time fluorescence quantitative polymerase chain reaction and Western blot were used to detect the relative mRNA and protein expression levels of NLRP3, cleaved-GSDMD, cleaved-Caspase-1 in each group of cells. Single factor analysis of variance was used for comparison among the three groups. ResultsIn vivo animal experiments: compared with the DM group, the expression of NLRP3, cleaved-GSDMD, and cleaved-Caspase-1 in the retina of normal control group and DM+Met group mice was significantly reduced, with significant difference among the 3 groups (F=43.478, 36.643, 24.464; P＜0.01). In vitro cell experiment and flow cytometry showed that the pyroptosis rate of AGE group was significantly higher than that of N group and AGE+Met group (F=32.598, P＜0.01). The DCFH-DA detection results showed that the intracellular ROS levels in the N group and AGE+Met group were significantly lower than those in the AGE group, with the significant difference (F=47.267, P＜0.01). The mRNA (F=51.563, 32.192, 44.473; P＜0.01) and protein levels (F=63.372, 54.463, 48.412; P＜0.01) of NLRP3, cleaved-GSDMD, and cleaved-Caspase-1 in hRMEC of the AGE+Met group were significantly reduced compared to the N group. ConclusionMet can down regulate the expression of NLRP3 inflammatory body related factors in hRMEC and inhibit pyroptosis.
Objectives To observe the expression of key proteins in the NLRP3/Caspase-1 pathway of pyroptosis in the mouse model of hepatic Echinococcus multilocularis (Em) infection and explore its correlation. Methods Twenty-five BALB/c mice were randomly divided into the control group and the infected group. The infected group was injected with 0.2 mL suspension of protoscolex (including 3 000 protoscoleces) injected under the liver capsule to establish a model of secondary infection with hepatic Em. The control group was treated without any treatments and conventional feeding was conducted. The mice were sacrificed at 1, 2, 3, and 5 months after infection. The liver was harvested and observed for gross morphology. HE staining and transmission electron microscopy were performed to observe the histopathological changes. The expressions of key proteins in the NLRP3/Caspase-1 pathway of pyroptosis and the IL-1β, a downstream factor of pyroptosis in the liver were detected by immunohistochemistry, Western blot and ELISA. Results Compared with the control group, the cystic lesions on the surface of liver tissues in the infected group mice gradually increased and protruded from the liver surface with the extension of infection time. HE staining showed various pathological changes such as inflammatory cell infiltration and fibrous hyperplasia in the liver lesions to varying degrees. After 2 months of Em infection, transmission electron microscope observation showed that the cell membrane of hepatocytes were broken and discontinuous, conforming to the "punching" phenomenon of pyroptosis. The results of ELISA showed that the concentration of IL-1β in liver homogenate of mice after 1, 2, 3 and 5 months of Em infection were significantly higher than that of the control group, and the difference was statistically significant (F=127.2, P<0.05). Immunohistochemical examination showed that the positive cell ratios of Caspase-1 and NLRP3 in liver of mice infected with Em at 1, 2, 3 and 5 months, were higher than that of the control group, and the difference were statistically significant (F=114.6, P<0.05; F=85.89, P<0.05). The Western blot results showed that the relative expression levels of Caspase-1, Xiaopi D, and NLRP3 proteins in the liver of infected mice showed a trend of first increasing (the expression of Caspase-1 and GSDMD reached their peak at 1 month of infection, while the expression of NLRP3 reached its peak at 2 months of infection) and then decreasing. There were statistically significant differences between the infection groups at different time points and the control group, as well as comparison between the infection groups at different time points there were also statistically significant differences (all P<0.05). Conclusion It is feasible to establish mouse Em infection model by “skin incision and liver puncture through abdominal muscle layer”. There is a new type of programmed cell death, pyroptosis, after Em infection in mouse liver. It may play a role in inflammation amplification through pyroptosis NLRP3/Caspase-1 pathway.
Objective To investigate the role and mechanisms of trimetazidine (TMZ) in intensive care unit-acquired weakness (ICU-AW). Methods Seventy wild-type male C57BL/6 mice were selected and the ICU-AW mouse model was constructed by intraperitoneal injection of different concentrations of lipopolysaccharide (LPS). The body weights, grip strengths, and 96-hour survival rates of each group were observed, and the optimal concentration of LPS and time of sampling were screened out, the mRNA and protein expression of the gastrocnemius muscle atrophic proteins Atrogin-1 and muscle-specific RING finger protein 1 (MuRF1) were further detected to verify the success of modelling, and LPS (12 mg/kg) was used as the subsequent modelling concentration according to the preliminary results. After successful modelling, another 70 mice were randomly divided into normal control group (Normal group), LPS solvent (Vehicle) group, LPS group, LPS+TMZ solvent group, LPS+TMZ group, LPS+TMZ+AC-YVAD-CMK (AC) solvent group, and LPS+TMZ+AC group, with 10 mice in each group. The Normal group did not have any intervention; the Vehicle group was injected intraperitoneally with an equal volume of saline with LPS; the remaining groups were injected intraperitoneally with LPS (12 mg/kg); after the completion of the LPS injection, the LPS+TMZ group, the LPS+TMZ+AC solvent group, and the LPS+TMZ+AC group were given TMZ (5 mg/kg) by gastric gavage once a day for 4 days. The LPS+TMZ solvent group was given TMZ equivalent saline gavage once a day for 4 days. The LPS+TMZ+AC group was injected intraperitoneally with the cysteinyl aspartate specific proteinase 1 (Caspase-1) inhibitor AC-YVAD-CMK (AC, 6.5 mg/kg) 1 h before LPS injection, and the LPS+TMZ+AC solvent group was injected with an equal amount of AC solvent phosphate buffer. At the end of TMZ treatment, body weight, grip strength, 96-hour survival rate, mRNA and protein expression of MuRF1, Atrogin-1, Caspase-1, and gasdermin D (GSDMD) in gastrocnemius muscle, as well as serum IL-1β and IL-18 concentrations in mice were detected in each group, and the gastrocnemius muscle was stained with HE to observe histopathological changes. Results Compared with the Normal group, mice in the LPS (12 mg/kg) and LPS (14 mg/kg) groups showed significant decreases in body weight and grasping strength and the weakening was most obvious at 3 - 5 d (P<0.05), but the survival rate of the LPS (12 mg/kg) group was higher than that of the LPS (14 mg/kg) group (P<0.05), the HE staining of gastrocnemius muscle showed that the mice in the LPS (12 mg/kg) group was significantly atrophied compared with that of the Normal group, and the gene and protein expression of MuRF1 and Atrogin-1 were significantly elevated (P<0.05), and the mice injected with LPS (12 mg/kg) for 4 days (96 h) were finally selected as the conditions for subsequent experimental modelling and sampling.The mRNA and protein expression of Caspase-1 and GSDMD in skeletal muscle was significantly higher in the LPS group compared with the Normal and Vehicle groups (P<0.01), and the concentrations of serum IL-1β and IL-18 were significantly higher(P<0.01). Mice in the TMZ group showed significant improvement in body weight, grip strength, survival rate, and degree of muscle atrophy compared with the LPS and TMZ solvent groups (P<0.05); gene and protein levels of MuRF1, Atrogin-1, Caspase-1, and GSDMD in the gastrocnemius muscle were significantly reduced (P<0.05); and levels of serum IL-1β and IL-18 were significantly reduced (P<0.05) ); the mice in the LPS+TMZ+AC group had significantly improved body weight, grip strength, survival rate, and muscle atrophy compared with the LPS+TMZ group and the LPS+TMZ+AC solvent group (P<0.05), and the gene and protein contents of MuRF1, Atrogin-1, Caspase-1, and GSDMD in the gastrocnemius muscle were reduced (P<0.05), and the serum IL-1β and IL -18 concentrations were reduced (P<0.05). Conclusion TMZ is able to exert a skeletal muscle protective effect by inhibiting Caspase-1/GSDMD-mediated pyroptosis, which is an important reference for the prevention and treatment of ICU-AW.
Objective To screen pyroptosis-related miRNAs of acute aortic dissection (AAD) from the GEO database, and analyze and verify their functions. MethodsThe microarray data set based on the miRNA chip in the GEO database was downloaded, the differentially expressed miRNAs were screened, and the target genes were predicted by the miRWalk database. Pyroptosis-related genes (PRGs) were searched in the PubMed database with "pyroptosis" as the keyword, and the intersection of PRGs and differential miRNAs predicting target genes were taken as AAD PRGs by Venn diagram. GO and KEGG enrichment analyses were performed. CytoHubba was used to screen the critical AAD PRGs and then the AAD pyroptosis-related miRNAs were identified. Aortic tissues were collected from gender- and age-matched AAD patients and healthy people, and the critical PRGs and miRNAs were verified by Western blotting and RT-qPCR. ResultsA total of 46 AAD differentially expressed miRNAs were screened, and 49 AAD PRGs were obtained by Venn diagram. GO enrichment analysis showed that the genes played a vital role in apoptosis regulated by cysteine endopeptidases. KEGG analysis showed that the genes enriched in Salmonella infection, necroptosis, and Nod-like receptor signaling pathways. CytoHubba screened the critical AAD PRGs such as cysteine aspartase-1 (Caspase-1), tumor necrosis factor (IL)-1β, and tumor necrosis factor (TNF), then obtained 12 AAD pyroptosis-related miRNAs. Aortic tissues were collected from 6 AAD patients and 6 healthy people. There were 5 males and 1 females in the AAD group with an average age of 48.70±6.35 years, and 4 males and 2 females in the healty control group with an average age of 45.30±4.58 years. There was no statistical difference between the two groups in terms of gender, age, smoking history, hypertension, diabetes, or coronary heart disease (P>0.05). Western blotting and RT-qPCR results showed that Caspase-1 was up-regulated in the AAD patients' aortic tissues compared with the healthy aorta, and the corresponding miRNAs were miR-198, miR-3202, and miR-514b-5p, which were all down-regulated. Conclusion Through bioinformatics analysis and verification, the critical AAD PRGs are Caspase-1, IL-1β, and TNF, and Caspase-1 is up-regulated and 3 corresponding pyroptosis-related miRNAs are down-regulated, which provides new ideas for the molecular mechanism and targeted therapy of AAD cell pyroptosis.