ABSTRACT
Pyroptosis is a novel process of programmed inflammatory necrosis, which is closely related to microbial infections and autoimmune diseases. In recent years it has been proved that Gasdermin D is an executive protein of pyroptosis. Cleaved Gasdermin D leads to the formation of pores in cell membrane to induce pyroptosis, and the release of inflammatory factors such as IL-1β and IL-18 aggravates the occurrence of inflammatory responses. With the deepening of Gasdermin D research, it is gradually clear its protein structure and activation sites, which has other activation pathways apart from inducing inflammasome activation. Activation of Gasdermin D does not necessarily mean cell death, even if it could induce the formation of pores in cell membrane and regulation of inflammatory cytokine secretion. These findings offer insight into Gasdermin D function and change our understanding of pyroptosis and programmed necrosis. The recent progress of Gasdermin D is highlighted in this review.
ABSTRACT
ObjectiveTo observe the changes of AIM2 ( absent in melanoma 2) inflammasome during early murine cytomegalovirus (MCMV) infection.MethodsBALB/c mice were randomly divided into two groups.One was infected with MCMV Smith for establishing disseminated infection,the other was sham-inoculated control.On days 1,3,5 and 7 of the experiment,three mice of each group were randomly chosen to be killed separately.The expression of AIM2,ASC and caspase-1 in splenic macrophages was detected by Western blot,the levels of IL-1β and IL-18 in sera were measured by double antibody sandwich ELISA,and the viral titers in salivary gland tissues were quantified by a standard plaque assay.Results The MCMV titers in salivary gland tissues were gradually increased in MCMV-infected mice on days 3,5 and 7,while the expressions of AIM2 in macrophages were began to increase on day 1 and significantly increased and reached the highest level on day 3 but gradually decreased afterwards.The relative intensity of AIM2 on day 3 differed significantly between the MCMV-infected mice and the controls (1.121±0.243 vs 0.240±0.046,P＜0.01,t test),as did ASC ( 1.318±0.333 vs 0.248±0.090,P＜0.01 ) and caspase-1 ( 1.085±0.243 vs 0.247±0.064,P＜0.01 ).Meanwhile,the levels of IL-1β and IL-18 in MCMV-infected mice were (112.72±5.20) pg/ml and (42.74±4.23) pg/ml,and the levels were significantly higher (P＜0.01 ) than those in controls [ (47.86±4.35) pg/ml and (22.60±2.82) pg/ml].ConclusionThese results demonstrate that AIM2 inflammasome is activated in macrophages during early MCMV infection and could be as a therapeutic target for CMV-induced diseases.