| Research backgroundAcute myeloid leukemia(AML)is a common hematological malignancy characterized by high heterogeneity.It is featured with malignant clonal proliferation of hematopoietic stem cells in bone marrow,which leads to high infiltration of leukemia cells in bone marrow,peripheral blood,as well as other tissues and organs,thereby affecting the normal function of bone marrow,tissues and organs.The clinical manifestations of patients are mainly exhaustion,congestion,bleeding,and increased risk of infection.Due to the lack of specificity and rapid progress of early clinical manifestations,the diagnosis and treatment for patients are often delayed.At present,chemotherapy is the main treatment for acute myeloid leukemia,which is often combined with other treatments,such as targeted therapy and bone marrow transplantation.However,the current complete remission(CR)rate is still low and the recurrence rate of patients is high.Therefore,it is of great significance for the treatment and prognosis of acute myeloid leukemia to continue to find a variety of combined adjuvant therapeutic strategies.Bile acid is an important metabolic product of the body and plays an important role in maintaining homeostasis.As an important component of bile acid,chenodeoxycholic acid(CDCA)has an important effect on the metabolism of the body and on many carcinomas,such as endometrial cancer and esophageal cancer.Meanwhile,studies have reported that bile acid plays a certain inhibitory role in hematological illnesses.However,the specific mechanism has not been fully studied.Therefore,further researches on the specific mechanism in the progression and development of AML is of great significance for the diagnosis and treatment of AML.Mitochondria,as important organelle of energy metabolism in cells,play an important role in the physiological and pathological process of cells.Abnormal mitochondrial function is closely related to the occurrence,development and drug resistance of AML.At the same time,mitochondria are closely correlated with other organelles in cells,and the interaction between organelles also plays an essential role in the development of diseases.Lipid droplets,as another important organelle in the cell,have a dynamic relationship with mitochondria.However,their interaction has not been fully studied in AML.Therefore,it is of great significance to study their specific effects in AML.Macrophage plays an important role in the progression and development of AML,and inducing and regulating macrophage immunity has an important effect on the treatment of AML.Bile acids have an influence in the immune response of macrophages,which needs further study in AML.Therefore,exploring the effects of CDCA on macrophages is expected to provide new perspective for the treatment and prognosis of AML.Research purposeTo explore the role of chenodeoxycholic acid(CDCA)in the progression of acute myeloid leukemia,and further study the specific effects of mitochondria,lipid droplets and lipid peroxidation to provide new prospects for the treatment and prognosis of AML patients.Research method1.Detection of cell proliferation and apoptosis:AML cell lines THP-1 and Molm13 were added with CDCA respectively,and their effects on AML cells were detected by flow cytometry.2.Mitochondrial function detection:For CDCA-treated AML cells,changes in mitochondrial membrane potential,mitochondrial mass,Reactive Oxygen Species(ROS),etc.were detected by flow cytometry and confocal microscope.3.Detection of lipid droplets and lipid peroxidation:Corresponding BODIPY dye was added to CDCA-treated AML cells to detect changes of lipid droplets and lipid peroxidation.4.To establish the relationship between mitochondria and lipid droplets:After clearance of ROS,analyzing the level of intracellular p38 phosphorylation,the expression of DGAT1 which is related to lipid droplet synthesis and the change of lipid droplet content.5.Animal experiment:Establish mouse model of AML to verify the role of CDCA in the progression of AML.6.Detection of macrophage polarization:By inducing macrophages,PCR was used to detect the expression of cell markers.Research results1.In vitro cell experiments showed that CDCA could inhibit the proliferation of AML cell lines and promote the cell apoptosis.2.Further experiments showed that after the treatment of CDCA in AML cells,CDCA could directly combine with mitochondria,resulting in decreased mitochondrial membrane potential,decreased mitochondrial mass,and increased intracellular ROS level.3.Meanwhile,experimental results showed that in AML cells treated with CDCA,intracellular lipid droplet content,lipid peroxidation level,and expression of lipid droplet synthesis-related protein DGAT1 were increased.After adding ROS scavenger NAC,the expression level of DGAT1 and the lipid droplet abundance decreased.4.Animal experiments further demonstrated that CDCA could delay the progression of AML.5.PCR results showed that CDCA could inhibit the polarization of M2 macrophages.Research conclusionOur study found that CDCA lead to the increase of intracellular ROS levels by disrupting mitochondrial function to promote the increase of MAPK p38 phosphorylation level and the expression of lipid droplet synthesis-related protein DGAT1,thereby leading to the increase of lipid droplet synthesis and lipid peroxidation level,and finally playing a role in inhibiting the proliferation and promoting the cell death of AML cells.It could inhibit M2 macrophage polarization as well.It is expected to provide a new prospective idea for the treatment and prognosis of AML. |
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