| Objective: The mononuclear macrophage system is an important defense system in the human body,consisting of monocytes,macrophages in each tissue,and protomononuclear and juvenile monocytes,all of which belong to the mononuclear cell family.Hematopoietic stem cells of the bone marrow.Macrophages are the effector cells of this system,and have different morphology and nomenclature depending on the location,such as Kupffer cells in the liver microglia in the brain.Macrophages have various functions such as phagocytosis,killing of tumor cells,antigen presentation in specific immune responses,activation and regulation of immune responses.Epithelial-mesenchymal transition(EMT)is the process by which epithelial cells undergo phenotypic changes and develop into mesenchymal/SM-like cells.Similarly,endothelial cells(ECs)can acquire a mesenchymal or SM-like phenotype,a process known as endothelium-interstitial transformation(End MT).End MT was originally described in the physiological process of heart valve formation.It was subsequently discovered that End MT can also occur in different organs such as kidneys,liver and heart,patients with fibrotic diseases,and diabetic patients and metastatic tumors.Eventually it became a key driver of many different pathologies,characterized by endothelial cell surface markers such as platelet endothelial cell adhesion molecule-1(PECAM-1 / CD31)and vascular endothelial cadherin(VE-cadherin),interstitial cells.Surface markers?-smooth muscle actin(?-SMA),smooth muscle 22?(SM22?),vimentin,fibroblast-specific protein 1(FSP1),and ECM proteins such as fibronectin(FN)and collagen are up-regulated.The Hippo pathway is an evolutionarily very conserved signaling pathway consisting mainly of the tandem kinase MST,LATS and the downstream co-transcriptional activator YAP/TAZ.As a co-transcription factor,YAP/TAZ binds to other transcription factors and regulates the expression of downstream target genes.It plays an important role in regulating organ size,tissue homeostasis,and tumorigenesis.Protein kinase C(PKC)is an important mediator in cell signal transduction pathways,with a variety of different subtypes,and is involved in the regulation of a wide range of biological processes.CXCR4 is a member of the CXC chemokine receptor family that specifically binds to the chemokine CXCL12.It is known that the signal axis formed by the two has a chemotactic effect on a variety of cells,and plays an important regulatory role in the process of homing,mobilization,cancer cell metastasis,viral infection,and inflammatory diseases of hematopoietic stem cells.In the preliminary work,we found that End MT phenomenon occurred during the differentiation of monocytes into macrophages induced by PKC activator PMA.Meanwhile,Hippo pathway was activated and CXCR4 expression was increased.We will explore the regulation of Hippo pathway on the expression of End MT and CXCR4 in this cell differentiation model,and provide theoretical basis for clarifying the specific mechanism of monocyte infiltration.Methods:PMA-induces differentiation of THP-1 cells into macrophages as a research model.1.Flow cytometry was used to detect the expression changes of cell surface mesenchymal markers before and after differentiation;2.The expression of interstitial markers in cells was detected by Western blot;3.Rhodamine-Phalloidin peptide detects cell morphology changes by staining with cytoskeletal proteins;4.Bioinformatics analysis of genes are interrelated.Results:1.Mononuclear/macrophage differentiation is accompanied by decreased expression of endothelial markers and enhanced expression of interstitial markers;2.PKC regulates the expression of downstream YAP1 and interstitial markers;3.In mononuclear/macrophage differentiation,YAP1 affects the expression of endothelial and mesenchymal markers;4.YAP1 regulates the expression of the chemokine receptor CXCR4.Conclusion:1.Mononuclear/macrophage differentiation is a special form of endothelium-interstitial transformation;2.The PKC/YAP signal axis regulates the expression of CXCR4. |
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