OBJECTIVE: To investigate the release of exosome (Exo) from leukocyte-depleted red cell suspension (LDRCS) at different storage time and its regulation on proliferation of hematological tumor cells and possible mechanism. METHODS: The Exo (RBC-Exo) in LDRCS at different storage time was obtained by ultracentrifugation, and the morphology and immunological marker of RBC-Exo were detected by transmission electron microscopy and Western blot, respectively. The particle size distribution of RBC-Exo in LDRCS at different storage time was detected by Dynamic Light Scattering. CCK-8 assay was used to explore the effect of RBC-Exo on hematological tumor cell proliferation. Western blot was used to detect the expression of proliferation-related proteins in hematological tumor cells after co-culture with RBC-Exo. RESULTS: RBC-Exo was isolated, which was characterized by cup-like shape, particle size distribution ranged from 20 to 200 nm, CD63/TSG101 enriched, Calnexin negative, CD235a positive and CD41 negative. The particle size distribution of RBC-Exo from LDRCS between middle was not significantly different and late stored stage. But the particle size distribution of RBC-Exo at middle-late stored stage(>14 d) was larger than that at early stored stage (≤14 days). Compared with the control group, RBC-Exo could significantly promote the proliferation of HBL1, U2932 and Jurkat cells. Compared with the control group, the cycle-related protein P21 was significantly down-regulated in HBL1, U2932 and Jurkat cells after co-culture with RBC-Exo for 3 days, while the anti-apoptotic protein BCL-2 was not changed significantly. CONCLUSION The morphology of RBC-Exo from LDRCS at middle-late stored stage was different from that at early stored stage. RBC-Exo could promote the proliferation of hematological tumor cells, possibly by regulating the expression of cycle-associated protein P21.
Cell Proliferation ; Erythrocytes ; Exosomes/metabolism* ; Hematologic Neoplasms/metabolism* ; Humans ; Leukocytes

Cytokines ; metabolism ; Humans ; Leukocytes, Mononuclear ; immunology ; secretion ; Ubiquitin ; blood

OBJECTIVE: To explore the expression patterns, prognostic implications, and biological role of leukotriene B4 receptor (LTB4R) in patients with acute myeloid leukemia (AML). METHODS: We collected the data of mRNA expression levels and clinical information of patients with AML from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database for mRNA expression analyses, survival analyses, Cox regression analyses and correlation analyses using R studio to assess the expression patterns and prognostic value of LTB4R. The correlation of LTB4R expression levels with clinical characteristics of the patients were analyzed using UALCAN. The co-expressed genes LTB4R were screened from Linkedomics and subjected to functional enrichment analysis. A protein-protein interaction network was constructed using STRING. GSEA analyses of the differentially expressed genes (DEGs) were performed based on datasets from TCGA-LAML stratified by LTB4R expression level. We also collected peripheral blood mononuclear cells (PBMCs) from AML patients and healthy donors for examination of the mRNA expression levels of LTB4R and immune checkpoint genes using qRT-PCR. We also examined serum LTB4R protein levels in the patients using ELISA. RESULTS: The mRNA expression level of LTB4R was significantly increased in AML patients (4.898±1.220 vs 2.252±0.215, P < 0.001), and an elevated LTB4R expression level was correlated with a poor overall survival (OS) of the patients (P=0.004, HR=1.74). LTB4R was identified as an independent prognostic factor for OS (P=0.019, HR=1.66) and was associated with FAB subtypes, cytogenetic risk, karyotype abnormalities and NPM1 mutations. The co- expressed genes of LTB4R were enriched in the functional pathways closely associated with AML leukemogenesis, including neutrophil inflammation, lymphocyte activation, signal transduction, and metabolism. The DEGs were enriched in differentiation, activation of immune cells, and cytokine signaling. Examination of the clinical serum samples also demonstrated significantly increased expressions of LTB4R mRNA (P=0.044) and protein (P=0.008) in AML patients, and LTB4R mRNA expression was positively correlated with the expression of the immune checkpoint HAVCR2 (r= 0.466, P=0.040). CONCLUSION LTB4R can serve as a novel biomarker and independent prognostic indicator of AML and its expression patterns provide insights into the crosstalk of leukemogenesis signaling pathways involving tumor immunity and metabolism.
Humans ; Leukemia, Myeloid, Acute/metabolism* ; Leukocytes, Mononuclear/metabolism* ; Prognosis ; RNA, Messenger/metabolism* ; Receptors, Leukotriene B4/genetics*

Although widely applied in treating hematopoietic malignancies, transplantation of hematopoietic stem/progenitor cells (HSPCs) is impeded by HSPC shortage. Whether circulating HSPCs (cHSPCs) in steady-state blood could be used as an alternative source remains largely elusive. Here we develop a three-dimensional culture system (3DCS) including arginine, glycine, aspartate, and a series of factors. Fourteen-day culture of peripheral blood mononuclear cells (PBMNCs) in 3DCS led to 125- and 70-fold increase of the frequency and number of CD34⁺ cells. Further, 3DCS-expanded cHSPCs exhibited the similar reconstitution rate compared to CD34⁺ HSPCs in bone marrow. Mechanistically, 3DCS fabricated an immunomodulatory niche, secreting cytokines as TNF to support cHSPC survival and proliferation. Finally, 3DCS could also promote the expansion of cHSPCs in patients who failed in HSPC mobilization. Our 3DCS successfully expands rare cHSPCs, providing an alternative source for the HSPC therapy, particularly for the patients/donors who have failed in HSPC mobilization.
Antigens, CD34/metabolism* ; Hematopoietic Stem Cell Transplantation ; Hematopoietic Stem Cells ; Humans ; Leukocytes, Mononuclear/metabolism* ; Peptides/metabolism*

P-selectin, one of the membrane proteins, expresses on platelet and endothelia and interacts with P-selectin glycoprotein ligand-1 (PSGL-1) on leukocyte membrane. This interaction mediates leukocytes rolling on endothelial membrane and then induces leukocyte recruitment to the site of infection or tissue injury. In the present study, we constructed the recombinant wild type human P-selectin, its calcium-binding sites mutants and recombinant PSGL-1-globulin (PSGL-1-Rg). They expressed in Sf9 cells by using the baculovirus expression system and were purified by TalonTM metal or Protein A affinity chromatography. The results showed that the recombinant PSGL-1-Rg interacted with recombinant wild type P-selectin and two P-selectin mutants with 2 calcium-binding sites mutation respectively, but could not bind to the P-selectin mutant with all 4 calcium-binding sites mutation. Therefore, we verified the importance of P-selectin calcium-binding sites for its interaction with PSGL-1.
Binding Sites ; Calcium ; metabolism ; Humans ; Leukocytes ; metabolism ; Membrane Glycoproteins ; metabolism ; Mutation ; P-Selectin ; metabolism ; Recombinant Proteins ; metabolism

Objective To investigate the expressions of IL-18, IL-18 binding protein isoform a (IL-18BPa) and IL-18 receptor α (IL-18Rα) in blood CD4⁺ Th2 cells of patients with allergic rhinitis (AR) and the effects of allergens on their expressions. Methods Blood samples of AR patients and healthy control subjects (HCs) were collected. Peripheral blood mononuclear cells (PBMCs) and CD4⁺ T cells sorted by immunomagnetic beads were stimulated by crude extract of Artemisia sieversiana wild allergen (ASWE), Platanus pollen (PPE) and house dust mite extract (HDME). Flow cytometry was used to detect the expression of IL-18, IL-18BPa and IL-18Rα in CD4⁺ Th2 cells, and BioPlex was used to detect the level of plasma IL-4 and analyze its correlation with the proportion of IL-18⁺ Th2 cells. Results Compared with HCs, the proportion of IL-18⁺ cells was increased in Th2 cells of AR patients; MFI of IL-18 was increased, while that of IL-18Rα was decreased. Moreover, allergens induced IL-18 and IL-18Rα expression in sorted CD4⁺ Th2 cells of HCs and induced IL-18Rα in that of AR patients. Additionally, elevated plasma IL-4 level was found in AR patients, which was moderately correlated with the percentage of IL-18⁺ Th2 cells. Conclusion Allergens may be involved in the pathogenesis of AR by inducing expression of IL-18 in peripheral blood CD4⁺ Th2 cells.
Humans ; Th2 Cells ; Interleukin-18/metabolism* ; Up-Regulation ; Leukocytes, Mononuclear/metabolism* ; Interleukin-4/metabolism* ; Rhinitis, Allergic/metabolism* ; Allergens ; Cytokines/metabolism*

OBJECTIVE: To observe the effect of astaxanthin (ASTA) on the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in suspended leukocyte-depleted red blood cells stored for transfusion. METHODS: The suspended leukocyte-depleted red blood cells were randomly divided into group A, B, C and D. The ASTA was added into preservation solution of suspended leukocyte-depleted red blood cells of group B, C and D with the final concentration 5, 10 and 20 μmol/L, respectively, while DMSO was added into cells of group A in the same volume. After 7, 14, 28 and 42 days of storage, the reactive oxygen species (ROS) content in red blood cells was detected by fluorescence microplate reader, malondialdehyde (MDA) content was detected by thiobarbituric acid (TBA) method, activity of SOD was detected by xanthine oxidase method, the activity of CAT was detected by visible light method, and activity of GSH-Px was detected by colorimetry. RESULTS: After 7, 14, 28 and 42 days of storage, the contents of ROS and MDA in suspended red blood cells of group B, C and D were significantly lower(P<0.05), while the activities of SOD and GSH-Px were higher than those of group A(P<0.05); and CAT activity in cells treated by ASTA was significantly higher at 28 and 42 days of storage in comparison with that of group A(P<0.05). There were positive correlations between the ROS, MDA content in suspended red blood cells of group A, B, C, D and storage time(P<0.01), while negative correlation between SOD, CAT, GSH-Px activity and storage time(P<0.01). CONCLUSION ASTA can decrease the oxidative stress level and peroxide damage degree by increasing the antioxidant enzyme activities in suspended leukocyte-depleted red blood cells during storage.
Antioxidants ; Catalase/metabolism* ; Erythrocytes ; Leukocytes ; Oxidative Stress ; Superoxide Dismutase/metabolism* ; Xanthophylls

OBJECTIVE: To explore the similarities and variations of biological phenotype and cytotoxicity of human umbilical cord blood natural killer cells (hUC- NK) after human umbilical cord blood-derived mononuclear cells (hUC-MNC) activated and expanded by two in vitro high-efficient strategies. METHODS: Umbilical cord blood mononuclear cells (MNC) from healthy donor were enriched by Ficoll-based density gradient centrifugation. Then, the phenotype, subpopulations, cell viability and cytotoxicity of NK cells derived from Miltenyi medium (denoted as M-NK) and X-VIVO 15 (denoted as X-NK) were compared using a "3IL" strategy. RESULTS: After a 14-day's culture, the contents of CD3^-CD56⁺ NK cells were elevated from 4.25%±0.04% (d 0) to 71%±0.18% (M-NK) and 75.2%±1.1% (X-NK) respectively. Compared with X-NK group, the proportion of CD3⁺CD4⁺ T cells and CD3⁺CD56⁺ NKT cells in M-NK group decreased significantly. The percentages of CD16⁺, NKG2D⁺, NKp44⁺, CD25⁺ NK cells in X-NK group was higher than those in the M-NK group, while the total number of expanded NK cells in X-NK group was half of that in M-NK group. There were no significant differences between X-NK and M-NK groups in cell proliferation and cell cycle, except for the lower percentage of Annexin V+ apoptotic cells in M-NK group. Compared with X-NK group, the proportion of CD107a⁺ NK cells in M-NK group were higher under the same effector-target ratio (E∶T) (P<0.05). CONCLUSION The two strategies were adequate for high-efficient generation of NK cells with high level of activation in vitro, however, there are differences in biological phenotypes and tumor cytotoxicity.
Humans ; Fetal Blood ; Killer Cells, Natural ; T-Lymphocytes ; Leukocytes, Mononuclear/metabolism* ; Cell Proliferation ; CD56 Antigen/metabolism*

Blood Coagulation ; physiology ; Blood Platelets ; metabolism ; Cell Communication ; Factor X ; metabolism ; Humans ; Leukocytes ; metabolism ; Thromboplastin ; metabolism ; physiology

OBJECTIVE: To investigate the effect of circulating exosomes (EXO) on T cell function in patients with sepsis. METHODS: Plasma EXO were obtained by ultracentrifugation from 10 patients with sepsis admitted to the emergency intensive care unit of Guangdong Provincial People's Hospital Affiliated to Southern Medical University. Transmission electron microscopy observation, nanoparticle tracking analysis (NTA), and Western blotting were used to detect EXO markers to identify their characteristics. Furthermore, peripheral blood mononuclear cells (PBMC) were isolated from the peripheral blood of 5 healthy volunteers, primary T cells were sorted by magnetic beads and expanded in vitro. After 24 hours of intervention with different doses (0, 1, 2.5, 5, 10 mg/L) of circulating EXO in patients with sepsis, T-cell activity was assessed using a cell counting kit-8 (CCK-8). The expression of T cell activation indicators CD69 and CD25 were observed using flow cytometry. Additional evaluations were performed on immunosuppressive indicators including the expression of programmed cell death 1 (PD-1) in CD4⁺ T cells and the proportion of regulatory T cell (Treg). RESULTS: The identification results confirmed that the successful isolation of EXO from the plasma of sepsis patients. The expression level of circulating EXO in sepsis patients was higher than that in healthy control group (mg/L: 48.78±5.14 vs. 22.18±2.25, P < 0.01). After 24 hours of intervention with 5 mg/L of plasma EXO from sepsis patients, T cells activity began to show suppression [(85.84±0.56)% vs. (100.00±0.00)%, P < 0.05]. As the dosage increased, after 24 hours of intervention with 10 mg/L of EXO, T cells activity was significantly suppressed [(72.44±2.36)% vs. (100.00±0.00)%, P < 0.01]. Compared with the healthy control group, after T cells intervention with plasma EXO from sepsis patients, the expression of early activation marker CD69 was significantly reduced [(52.87±1.29)% vs. (67.13±3.56)%, P < 0.05]. Meanwhile, there was an upregulation of PD-1 expression in T cells [(57.73±3.06)% vs. (32.07±0.22)%, P < 0.01] and an increase in the proportion of Treg [(54.67±1.19)% vs. (24.60±3.51)%, P < 0.01]. However, the expression of the late activation marker CD25 remained stable [(84.77±3.44)% vs. (85.93±2.32)%, P > 0.05]. CONCLUSIONS Circulating EXO in sepsis patients induce T cell dysfunction, which may be a novel mechanism lead to immunosuppression in sepsis.
Humans ; Leukocytes, Mononuclear ; Exosomes/metabolism* ; Programmed Cell Death 1 Receptor/metabolism* ; T-Lymphocytes, Regulatory/metabolism* ; Sepsis/metabolism*