Objective To prepare monoclonal antibodies against bovine CD4 and identify their basic biological characteristics. Methods Recombinant bovine CD4 (rHis-BoCD4 and rGST-BoCD4) was successfully expressed and purified by constructing a prokaryotic plasmid of bovine CD4 gene. The bovine CD4 monoclonal antibody was produced using hybridoma technology. The subtype and potency of the monoclonal antibody were identified and analyzed by ELISA, while specificity was analyzed through indirect immunofluorescence assay (IFA) and Western-blot. Results Four hybridoma cell lines, namely, 1H4, 6A10, 3F9 and 4G10, stably secreting monoclonal antibodies against BoCD4 were successfully obtained. The subclasses of the monoclonal antibodies subclass 6A10 was IgG2b and the rest of the monoclonal antibodies were of IgM type. Western-blot results showed that the four anti-bovine CD4 mAb strains were able to specifically bind to the bovine CD4 protein expressed in vitro. Indirect immunofluorescence assay showed that four monoclonal antibodies were able to specifically recognize the natural bovine CD4 protein. Flow cytometry assay showed that 3F9 was best to recognize bovine natural CD4 molecules. Conclusion Four monoclonal antibody strains with high specificity to natural bovine CD4 protein were successfully prepared, which lays the foundation for the subsequent studies on the function of bovine CD4 and diagnosis and treatment of bovine T-lymphocyte diseases.
Animals ; Antibodies, Monoclonal/isolation & purification* ; Cattle ; CD4 Antigens/genetics* ; Hybridomas/immunology* ; Antibody Specificity/immunology* ; Mice ; Mice, Inbred BALB C ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique, Indirect

Objective To investigate the effect of gentiopicroside on osteogenic differentiation of human bone marrow mesenchymal stem cells (BMSCs), and to determine whether its mechanism involves the stromal cell-derived factor 1(SDF-1)/C-X-C chemokine receptor 4 (CXCR4) pathway. Methods BMSCs were divided into six groups: normal culture control group, osteogenic induction model group, low-dose gentiopicroside (L-gentiopicroside, 10 μmol/L) group, medium-dose gentiopicroside (M-gentiopicroside, 20 μmol/L) group, high-dose gentiopicroside (H-gentiopicroside, 40 μmol/L) group, and H-gentiopicroside+SDF-1/CXCR4 pathway inhibitor (AMD3100) group (H-gentiopicroside+AMD3100, 40 μmol/L gentiopicroside+10 μg/mL AMD3100). Cell viability, apoptosis, ALP activity, mineralized nodule formation, and protein levels of the SDF-1/CXCR4 pathway were assessed using the CCK-8 assay, flow cytometry, ALP staining, Alizarin Red S staining, and Western blotting, respectively. Results No mineralized nodules were observed in either the control and model group, although the color of the model group deepened. Compared with the control group, the model group showed significantly increased A value, ALP activity, expression levels of Runt related transcription factor 2 (RUNX2), osteopontin (OPN), SDF-1, CXCR4 proteins, along with a lower apoptosis rate. Compared with the model group, the L-gentiopicroside, M-gentiopicroside and H-gentiopicroside groups showed dose-dependently (LCXCR4, along with correspondingly decreased apoptosis rates. However, compared with the H-gentiopicroside group, the H-gentiopicroside+AMD3100 group showed reduced A value, ALP activity, expression levels of RUNX2, OPN, SDF-1, and CXCR4, along with a higher apoptosis rate. Conclusion The promoting effect of gentiopicroside on osteogenic differentiation of BMSCs may be achieved by activating the SDF-1/CXCR4 signaling pathway.
Humans ; Receptors, CXCR4/genetics* ; Mesenchymal Stem Cells/metabolism* ; Chemokine CXCL12/genetics* ; Iridoid Glucosides/pharmacology* ; Osteogenesis/drug effects* ; Cell Differentiation/drug effects* ; Signal Transduction/drug effects* ; Cells, Cultured ; Apoptosis/drug effects* ; Bone Marrow Cells/metabolism*

OBJECTIVE: To explore the effects of hydroxychloroquine (HCQ) on immune mediators dysregulation in severe infection after chemotherapy in acute myeloid leukemia (AML) and its molecular mechanism. METHODS: Bone marrow or peripheral blood samples of 36 AML patients with severe infection (AML-SI) and 29 AML patients without infection (AML-NI) after chemotherapy were collected from the First Affiliated Hospital of Gannan Medical University from August 2022 to June 2023. In addition, the peripheral blood of 21 healthy subjects from the same period in our hospital was selected as the control group. The mRNA expressions of CXCL12, CXCR4 and CXCR7 were detected by RT-qPCR technology, and the levels of IL-6, IL-8 and TNF-α were detected by ELISA. Leukemia-derived THP-1 cells were selected and constructed as AML disease model. At the same time, bone marrow mesenchymal stem cells (BM-MSCs) from AML-SI patients were co-cultured with THP-1 cells and divided into Mono group and Co-culture group. THP-1 cells were treated with different concentration gradients of HCQ. The cell proliferation activity was subsequently detected by CCK-8 method and apoptosis was detected by Annexin V/PI double staining flow cytometry. ELISA was used to detect the changes of IL-6, IL-8 and TNF-α levels in the supernatant of the cell co-culture system, RT-qPCR was used to detect the mRNA expression changes of the core members of the CXCL12-CXCR4/7 regulatory axis, and Western blot was used to detect the expressions of apoptosis regulatory molecules and related signaling pathway proteins. RESULTS: CXCL12, CXCR4, CXCR7, as well as IL-6, IL-8, and TNF-α were all abnormally increased in AML patients, and the increases were more significant in AML-SI patients (P <0.01). Furthermore, there were statistically significant differences between AML-NI patients and AML-SI patients (all P <0.05). HCQ could inhibit the proliferation and induce the apoptosis of THP-1 cells, but the low concentration of HCQ had no significant effect on the killing of THP-1 cells. When THP-1 cells were co-cultured with BM-MSCs of AML patients, the levels of IL-6, IL-8 and TNF-α in the supernatance of Co-culture group were significantly higher than those of Mono group (all P <0.01). After HCQ intervention, the levels of IL-6, IL-8 and TNF-α in cell culture supernatant of Mono group were significantly decreased compared with those before intervention (all P <0.01). Similarly, those of Co-culture group were also significantly decreased (all P <0.001). However, the expression of the core members of the CXCL12-CXCR4/7 regulatory axis was weakly affected by HCQ. HCQ could up-regulate the expression of pro-apoptotic protein Bax, down-regulate the expression of anti-apoptotic protein Bcl-2, as well as simultaneously promote the hydrolytic activation of Caspase-3 when inhibiting the activation level of TLR4/NF-κB pathway, then induce the programmed death of THP-1 cells after intervention. CONCLUSION The core members of CXCL12-CXCR4/7 axis and related cytokines may be important mediators of severe infectious immune disorders in AML patients. HCQ can inhibit cytokine levels to reverse immune mediators dysregulation and suppress malignant biological characteristics of leukemia cells. The mechanisms may be related to regulating the expression of Bcl-2 family proteins, hydrolytically activating Caspase-3 and inhibiting the activation of TLR4/NF-κB signaling pathway.
Humans ; Leukemia, Myeloid, Acute/immunology* ; Hydroxychloroquine/pharmacology* ; Receptors, CXCR4/metabolism* ; Apoptosis/drug effects* ; Tumor Necrosis Factor-alpha/metabolism* ; Chemokine CXCL12/metabolism* ; Interleukin-8/metabolism* ; Interleukin-6/metabolism* ; Receptors, CXCR/metabolism* ; Mesenchymal Stem Cells ; THP-1 Cells

OBJECTIVE: To explore the effects and mechanisms of the C-X-C motif chemokine ligand 12/C-X-C motif chemokine receptor 4 (CXCL12/CXCR4) signaling axis on apoptosis and autophagy in SH-SY5Y neuronal cells subjected to oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro. METHODS: SH-SY5Y cells were divided into the following groups: OGD/R group and non-OGD/R group, with the OGD/R group subjected to OGD/R modeling and the non-OGD/R group receiving no treatment. Cells were also divided into CXCL12⁺ and CXCL12^- groups; the CXCL12⁺ group received 0.1 mg/L exogenous recombinant CXCL12 (rhCXCL12) at reoxygenation, while the CXCL12^- group did not. Another set of cells was divided into CXCL12+AMD3100 and CXCL12 groups; the CXCL12+AMD3100 group was pretreated with 2.5 mg/L AMD3100, a CXCR4 inhibitor, for 2 hours before OGD/R and received both 2.5 mg/L AMD3100 and 0.1 mg/L rhCXCL12 at reoxygenation, whereas the CXCL12 group received rhCXCL12 only. Additionally, cells were divided into small interfering RNA CXCR4 (siCXCR4) and small interfering RNA negative control (siNC) groups; the siCXCR4 group underwent CXCR4 knockdown before OGD/R modeling and received 0.1 mg/L rhCXCL12 at reoxygenation, while the siNC group, transfected with a negative control, received the same treatment. Protein expression of autophagy-related 16 (ATG16), microtubule-associated protein 1 light chain 3 (LC3), aquaporin-3 (AQP3), and CXCR4 was detected by Western blotting. Apoptosis rate and CXCR4 expression were measured by flow cytometry. RESULTS: Compared with the non-OGD/R group, the OGD/R group showed a significantly increased apoptosis rate and markedly decreased protein expression levels of ATG16, LC3, AQP3, and CXCR4 (all P < 0.05). CXCR4 fluorescent expression was also significantly reduced, suggesting that OGD/R simultaneously affects neuronal apoptosis and autophagy while inhibiting CXCR4 and AQP3 expression in SH-SY5Y cells. Compared with the CXCL12^- group, the CXCL12⁺ group exhibited no significant change in apoptosis rate but demonstrated significantly increased protein expression of ATG16, LC3, and AQP3 (ATG16/GAPDH: 1.21±0.10 vs. 1.00±0.00; LC3/β-actin: 1.22±0.10 vs. 1.00±0.00; AQP3/β-actin: 1.26±0.04 vs. 1.00±0.00; all P < 0.05). CXCR4 expression was also significantly enhanced (fluorescence intensity: 1.19±0.05 vs. 1.00±0.00, P < 0.05), indicating that CXCL12 may promote autophagy in OGD/R-injured SH-SY5Y cells via the CXCR4/AQP3 pathway. Compared with the CXCL12 group, the CXCL12+AMD3100 group showed no significant difference in apoptosis rate but significantly lower protein levels of ATG16 and LC3 (ATG16/GAPDH: 0.75±0.08 vs. 1.00±0.00; LC3/GAPDH: 0.86±0.07 vs. 1.00±0.00; both P < 0.05), suggesting that CXCL12 induces autophagy in OGD/R SH-SY5Y cells through CXCR4. Compared with the siNC group, the siCXCR4 group showed no significant change in apoptosis rate but significantly reduced protein expression of ATG16, LC3, AQP3, and CXCR4 (ATG16/GAPDH: 0.76±0.06 vs. 1.00±0.00; LC3/GAPDH: 0.79±0.11 vs. 1.00±0.00; AQP3/GAPDH: 0.81±0.05 vs. 1.00±0.00; CXCR4/GAPDH: 0.86±0.04 vs. 1.00±0.00; all P < 0.05), indicating that CXCR4 knockdown suppresses OGD/R-induced autophagy in SH-SY5Y cells likely via AQP3. CONCLUSIONS The CXCL12/CXCR4 signaling axis can regulate OGD/R-induced autophagy in SH-SY5Y cells through AQP3 without affecting apoptosis, indicating a role for this pathway in neuronal autophagy during cerebral ischemia/reperfusion injury.
Humans ; Receptors, CXCR4/metabolism* ; Chemokine CXCL12/metabolism* ; Autophagy ; Glucose/metabolism* ; Apoptosis ; Neurons/cytology* ; Oxygen/metabolism* ; Signal Transduction ; Cell Line, Tumor ; Cell Hypoxia ; Benzylamines ; Cyclams

OBJECTIVES: To observe the role of miR-139-5p and Notch1 signaling pathway in regulation of homing of bone mesenchymal stem cells (BMSCs) of asthmatic rats. METHODS: Normal rat BMSCs were co-cultured with bronchial epithelial cells from normal or asthmatic rats, followed by transfection with miR-139-5p mimics or a negative control sequence. The changes in cell viability and cell cycle were analyzed, and the cellular expressions of CXCR4 and SDF-1 were detected using immunofluorescence staining. The changes of BMSC homing after the transfection were observed, and the expressions of Notch1, RBP-J, and Hes1 mRNAs and proteins and Th1/Th2 cytokines were detected with RT-qPCR, Western blotting or ELISA. RESULTS: The co-cultures of BMSCs and asthmatic bronchial epithelial cells showed significantly decreased expressions of miR-139-5p, IL-2 and IL-12 and increased expressions of CXCR4, SDF-1, IL-5, IL-9, Notch1, RBP-J, and Hes1. Transfection with miR-139-5p mimics significantly increased the expressions of miR-139-5p, IL-2, CXCR4 and SDF-1 and lowered the expression levels of IL-5, IL-9, Notch1, activated Notch1, and Hes1 in the co-cultured cells. Correlation analysis showed that BMSC homing was positively correlated with miR-139-5p and IL-12 and negatively correlated with IL-5 expression. The expression of CXCR4 was negatively correlated with activated Notch1, and SDF-1 was positively correlated with miR-139-5p but negatively correlated with Notch1 expression. CONCLUSIONS High expression of miR-139-5p promotes homing of BMSCs in asthma by targeting the Notch1 signaling pathway to regulate the expressions of Th1/Th2 cytokines, thereby alleviating airway inflammation.
Asthma/genetics* ; Animals ; Mesenchymal Stem Cells/cytology* ; MicroRNAs/metabolism* ; Rats ; Transcription Factor HES-1/genetics* ; Signal Transduction ; Receptor, Notch1/genetics* ; Immunoglobulin J Recombination Signal Sequence-Binding Protein/genetics* ; Receptors, CXCR4/genetics* ; Coculture Techniques ; Rats, Sprague-Dawley ; Chemokine CXCL12/genetics* ; Epithelial Cells/metabolism*

Objective: To investigate the role of CD4⁺CD25⁺regulatory cell (CD4⁺CD25⁺Treg) in auditory neuropathy (AN) using a rat model of autoimmune auditory neuropathy. Methods: The SD rats were immunized with P0 protein emulsified in complete Freunds adjuvant for 8 weeks. The number of CD4⁺CD25⁺Treg in peripheral blood and cochlea and the expression of Foxp3 gene in cochlea were detected respectively 2, 4, 6 and 8 weeks after the immunization with P0 protein in rats. Then CD4⁺CD25⁺Treg were transferred intravenously to the AN rats at 2, 4, 6 and 8 weeks of the immunization, respectively. The change of auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) were detected, and the morphological changes in the inner ear were investigated. Results: The number of CD4⁺CD25⁺Treg in the peripheral blood of AN rats decreased gradually after 2, 4, 6 and 8 weeks of P0 protein immunization. The number of CD4⁺CD25⁺Treg in cochlea gradually increased with the prolongation of immunization time, but the expression of Foxp3 gene in cochlea gradually decreased over time. After intravenous transplantation of CD4⁺CD25⁺Treg in AN rats, the threshold of ABR response decreased, and DPOAE had no significant change. The number of spiral ganglion neurons in cochlea increased, and hair cells had no significant change under electron microscope. Conclusions: The decrease in the number and function of CD4⁺CD25⁺Treg reduces its inhibitory effect on autoimmune response and promotes the occurrence of autoimmune auditory neuropathy in AN rats. Adoptive transfer of CD4⁺CD25⁺Treg can reduce the autoimmune response and promote the recovery of autoimmune auditory neuropathy.
Animals ; Rats ; Forkhead Transcription Factors ; Myelin P0 Protein ; Rats, Sprague-Dawley ; T-Lymphocytes, Regulatory ; CD4 Antigens/immunology* ; Interleukin-2 Receptor alpha Subunit/immunology*

BACKGROUND: T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT), an inhibitory receptor expressed on T cells, plays a dysfunctional role in antiviral infection and antitumor activity. However, it is unknown whether TIGIT expression on T cells influences the immunological effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated vaccines. METHODS: Forty-five people living with HIV (PLWH) on antiretroviral therapy (ART) for more than two years and 31 healthy controls (HCs), all received a third dose of a SARS-CoV-2 inactivated vaccine, were enrolled in this study. The amounts, activation, proportion of cell subsets, and magnitude of the SARS-CoV-2-specific immune response of TIGIT + CD4 + and TIGIT + CD8 + T cells were investigated before the third dose but 6 months after the second vaccine dose (0W), 4 weeks (4W) and 12 weeks (12W) after the third dose. RESULTS: Compared to that in HCs, the frequency of TIGIT + CD8 + T cells in the peripheral blood of PLWH increased at 12W after the third dose of the inactivated vaccine, and the immune activation of TIGIT + CD8 + T cells also increased. A decrease in the ratio of both T naïve (T N ) and central memory (T CM ) cells among TIGIT + CD8 + T cells and an increase in the ratio of the effector memory (T EM ) subpopulation were observed at 12W in PLWH. Interestingly, particularly at 12W, a higher proportion of TIGIT + CD8 + T cells expressing CD137 and CD69 simultaneously was observed in HCs than in PLWH based on the activation-induced marker assay. Compared with 0W, SARS-CoV-2-specific TIGIT + CD8 + T-cell responses in PLWH were not enhanced at 12W but were enhanced in HCs. Additionally, at all time points, the SARS-CoV-2-specific responses of TIGIT + CD8 + T cells in PLWH were significantly weaker than those of TIGIT - CD8 + T cells. However, in HCs, the difference in the SARS-CoV-2-specific responses induced between TIGIT + CD8 + T cells and TIGIT - CD8 + T cells was insignificant at 4W and 12W, except at 0W. CONCLUSIONS TIGIT expression on CD8 + T cells may hinder the T-cell immune response to a booster dose of an inactivated SARS-CoV-2 vaccine, suggesting weakened resistance to SARS-CoV-2 infection, especially in PLWH. Furthermore, TIGIT may be used as a potential target to increase the production of SARS-CoV-2-specific CD8 + T cells, thereby enhancing the effectiveness of vaccination.
Humans ; Antibodies, Viral ; CD8-Positive T-Lymphocytes ; COVID-19/complications* ; COVID-19 Vaccines/immunology* ; HIV Infections/complications* ; Receptors, Immunologic ; SARS-CoV-2

Humans ; Neutrophils ; Receptors, Cell Surface ; GPI-Linked Proteins ; HIV Infections ; Isoantigens

Pulmonary fibrosis is an irreversible interstitial lung disease characterized by lung parenchyma remodeling and collagen deposition. In recent years, the incidence and mortality of pulmonary fibrosis caused by unknown causes have risen. However, its pathogenesis is still unclear. C-X-C motif chemokine ligand 12 (CXCL12)/C-X-C chemokine receptor 4 (CXCR4)/CXCR7 signal axis plays a critical regulatory role in pulmonary fibrosis disease. In addition, the signal axis has been shown to regulate recruitment and migration of circulating fibrocytes, mesenchymal stem cells to the damage lung tissue, the migration of endothelial cells, the proliferation and differentiation of fibroblasts and endothelial cells, which further affects the occurrence and progression of pulmonary fibrosis. In this review, we summarized the pathogenesis and treatment research progress of CXCL12 and its receptor CXCR4/CXCR7 in the occurrence and progression of pulmonary fibrosis.
Chemokine CXCL12 ; Endothelial Cells/pathology* ; Humans ; Ligands ; Lung/pathology* ; Pulmonary Fibrosis/pathology* ; Receptors, CXCR4

OBJECTIVE: To explore the improvement effect of CXC chemokine receptor 4 (Cxcr4) gene-modified bone marrow mesenchymal stem cell (BMSC)-derived exosomes on aplastic anemia (AA), and make a preliminary exploration of the mechanism. METHODS: Mouse BMSCs were isolated and cultured, then infected by recombinant lentivirus carrying Cxcr4 gene. The expression of green fluorescence was observed through fluorescence microscope, the expression of Cxcr4 mRNA was detected by real-time fluorescence quantitative PCR, and the BMSC-derived exosomes modified with Cxcr4 gene were extracted. Mouse models of AA were constructed, and control group, model group (AA), AA+BMSC group, AA+NC-BMSC group, AA+Cxcr4-BMSC group were set up. Except control group and model group, the other three groups of mice were injected 400 μl exosomes from different sources via the tail vein, after 2 weeks, the routine blood indices and the number of bone marrow nucleated cells were detected, the pathological changes of bone marrow were observed by HE staining, and the expression level of Treg cells was detected by flow cytometry. RESULTS: Mouse BMSCs were successfully isolated, and BMSCs with high expression of Cxcr4 and their exosomes were obtained. Compared with the control group, the number of red blood cell (RBC), white blood cell (WBC), and platelet (PLT), the hemoglobin (Hb) content and proportion of Treg cells in the peripheral blood of mice in the model group significantly decreased (P<0.01), as well as the number of bone marrow nucleated cells (P<0.01). The proliferation level of nucleated cells was low, and the medullary cavity was filled with a large number of fat cells. Compared with the model group, the number of RBC, WBC, PLT, the Hb content and proportion of Treg cells in the peripheral blood of mice in the AA+BMSC group, AA+NC-BMSC group, and AA+Cxcr4-BMSC group significantly increased (P<0.01), as well as the number of bone marrow nucleated cells (P<0.01), and pathological changes of bone marrow were improved. In addition, the number of RBC, WBC, PLT, the Hb content and proportion of Treg cells in the peripheral blood of mice in the AA+Cxcr4-BMSC group were significantly higher than those in the AA+BMSC group (P<0.01), as well as the number of bone marrow nucleated cells (P<0.01). CONCLUSION Injection of Cxcr4 gene-modified BMSC-derived exosomes has a certain improvement effect on AA mice, and the mechanism may be related to an increase of the proportion of Treg cells.
Anemia, Aplastic/metabolism* ; Animals ; Bone Marrow Cells ; Exosomes/metabolism* ; Humans ; Mesenchymal Stem Cells ; Mice ; Receptors, CXCR4