| Background: Acute ST-segment elevation myocardial infarction(STEMI)continues to be the leading cause of death worldwide,even in the era of reperfusion therapy.Most STEMI events can be attributed to plaque rupture,plaque erosion,or calcified nodules,which are different forms of atherosclerotic lesions.Myocardial necrosis after STEMI will be accompanied by the rapid accumulation of a large number of innate immune cells,such as monocytes,macrophages and neutrophils.These cells are key mediators of the innate immune response and play a critical role in atherosclerosis inflammation as well as myocardial remodeling following infarction.Innate lymphoid cells(ILCs)are newly discovered members of the lymphoid lineage and have been shown to be important components of innate immunity.ILCs have lymphocyte morphology,but lack antigen-specific receptor rearrangements,immune cells that do not have T,B cell antigen receptors,or other immune cell surface marker molecules.ILCs can be divided into "cytotoxic" ILCs(natural killer cells,NK cells)and "helper" ILCs according to the strength of their killing function."Helpful" ILCs are characterized by the expression of CD127 and can be divided into type 1 ILC(ILC1),type 2 ILC(ILC2),and type 3 ILC(ILC3).According to the differences in the expression of secreted cytokines and key transcription factors,ILCs can be divided into three subgroups: Groups 1,2,and 3.Group 1 ILCs include NK cells and ILC1 s,both of which have similar functions.ILC1 express high level of Tbet but lack expression of CD117;upon stimulation by cytokines interleukin(IL)-12 and IL-18,these produce T helper(Th)1-associated cytokine interferon(IFN)-? and TNF-?.The second group of ILCs,ILC2,is a subtype that can secrete Th2 cytokines such as IL5 and IL13.The differentiation and function of ILCs depend on the transcription factors GATA3 and ROR?.Th2-related cytokines are produced under the stimulation of TSLP,IL-25 and IL-33.The development of ILC2 requires the presence of IL-7.Group 3 ILCs include ILC3 and LTi cells,whose differentiation and function depend on the transcription factor ROR?t and produce IL-17 and/or IL-22.Therefore,ILCs play the important physiological roles in various acute and chronic inflammations.The role of ILC in the process of atherosclerosis in the mouse model has been proposed.In mouse models,mice deficient in T-bet,IFN-?,and IL-12 were shown to exhibit reduced plaque burden,and adoptive transfer of ILC1 was shown to accelerate atherosclerosis in a mouse model.High-fat feeding of mouse can alter the number of ILC2 and their production of cytokines.ILC2 selective genetic ablation in Ldlr-/-mice was shown to accelerate atherosclerosis development.However,the current research on ILC in AS is mostly concentrated on the basic animal research,and the specific role of ILC in STEMI is still unclear.Aim: This study aimed to explore the dynamic changes of ILCs in peripheral blood of STEMI patients and explore their clinical significance and possible functional changes in STEMI,and try to provide new potential intervention targets and ideas for the treatment of myocardial infarction.Methods: In this study,176 patients with new STEMI who were treated in the First Hospital of Jilin University for emergency revascularization and within 12 hours of onset were consecutively included.Meanwhile,52 patients without coronary heart disease excluded after the coronary angiography in the First Hospital of Jilin University during the same period were served as control groups.In the experiment,the clinical characteristics of the research subjects were collected,and peripheral blood samples were obtained for testing.Flow cytometry was employed to identify the characteristics and dynamic changes of ILC in peripheral blood PBMC of the STEMI patients.RNA-Seq was used to analyze the differentially expressed genes(DEGs)of human ILC1,and the expressions of the differential genes were further confirmed by RT-q PCR.The expression of immune cell-related genes was verified by flow cytometry.The secretion levels of related cytokines were detected by Elisa method.In addition,patients were followed up for up to 23 months,and the relationship between ILC and clinical outcomes were analyzed by the statistical methods.Results:(1)FACS analysis showed that in the acute stage of STEMI,t the number and percentage of total ILC and ILC1 in peripheral blood were significantly higher than those in the control group,while the percentage of ILC2 in total ILC was significantly decreased.After 3 days of STEMI onset,the percentage of ILC1 subtypes decreased,but remained higher than in controls.Pearson correlation analysis showed that an increase in ILC1 was associated with an increase in monocytes and a decrease in NK cells.(2)Linear regression analysis found that the percentage of ILC1 in STEMI is related with the peak of troponin and the Hs-CRP level.(3)In multivariate Cox regression analysis,the 3rd tertile of ILC1 was associated with a higher incidence of major adverse cardiovascular events(MACE)compared with the 1st tertile(hazard ratio: 2.26;95% confidence interval 1.56-3.27;P= 0.014).(4)RNA-sequencing(RNA-Seq)of ILC1 showed that a total of 4204 DEGs were found up-regulated and 4712 DEGs down-regulated on comparison of ILC1 s from STEMI patients and controls,among which 302 DEGs were related to cardiovascular disease.On further analysis,89 genes showed ?2 Log fold change(Log2 ratio)and 48 genes showed <-2 Log fold change(Log2 ratio).The number of up-regulated genes far exceeds the number of down-regulated genes.In addition,the changes in the FPKM values of the samples were also considered.Finally,17 down-regulated and 36 up-regulated genes were found to have cardiovascular-related functions,which were related to functions such as fluid shear stress,AS,platelet activation,and myocardial contraction.(5)The expressions of IFN-?,TNF-?,VCAM1,and MMP9 on ILC1 were verified by RT-q PCR.The expressions of IFN-?,TNF-?,VCAM1,and MMP9 on ILC1 in the STEMI group were significantly higher than those in the control group.These results were consistent with the results of RNA-seq.(6)The expressions of VCAM1 and MMP9 on ILC1 s were also verified by flow cytometry.The expressions of VCAM1 and MMP9 on ILC1 s from STEMI patients were higher than those in controls.These results were consistent with the results of RNA-seq.(7)In the STEMI group,the levels of the active cytokines IL-12 and IL-18 of ILC1 and the secreted cytokines IFN-? and TNF-? were significantly increased.Conclusions:(1)Total ILC and ILC1 numbers increased during the acute phase of STEMI,and the increase in total ILC was mainly driven by an increase in ILC1.(2)The percentage of ILC1 in the peripheral blood of STEMI patients was significantly increased in the acute phase,and the increase of the percentage of ILC1 was positively correlated with the incidence of MACE.The multivariate Cox regression results showed that the percentage of ILC1 was an independent predictor of MACE.(3)In the enriched KEGG analysis of ILC1,the genes of the antigen processing and presentation pathway and the apoptosis pathway were significantly enriched,but the differentiation of Th1 and Th2 cells was not obvious,which is related to the fact that ILCs belong to innate immune cells and can respond rapidly to stimuli.(4)The expression of MMP9,TNF-?,IFN-? and VCAM1 genes on ILC1 was significantly up-regulated,and the active cytokines IL-12,IL-18 and secreted cytokines IFN-? and TNF-? of ILC1 in serum were significantly increased.These suggest that ILC1 is amplified in acute myocardial infarction,and it is accompanied by functional changes at the gene level and protein level.Therefore,ILC1 may play an important physiological and pathological role in STEMI.The study of the role and mechanism of ILC1 may provide new intervention targets and ideas for the treatment of acute myocardial infarction. |
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