Somatostatin (SST) is an inhibitory polypeptide hormone that plays an important role in a variety of biological processes. Somatostatin receptor 2 (SSTR2) is the most widely expressed somatostatin receptor. However, the specific cell types expressing Sstr2 in the tissues have not been investigated. In this study, we detected the expression pattern of SSTR2 protein in mouse at different development stages, including the embryonic 15.5 days and the postnatal 1, 7, 15 days as well as 3 and 6 months, by multicolour immunofluorescence analyses. We found that Sstr2 was expressed in some specific cells types of several tissues, including the neuronal cells and astrocytes in the brain, the mesenchymal cells, the hematopoietic cells, the early hematopoietic stem cells, and the B cells in the bone marrow, the macrophages, the type Ⅱ alveolar epithelial cells, and the airway ciliated cells in the lung, the epithelial cells and the neuronal cells in the intestine, the hair follicle cells, the gastric epithelial cells, the hematopoietic stem cells and the nerve fibre in the spleen, and the tubular epithelial cells in the kidney. This study identified the specific cell types expressing Sstr2 in mouse at different developmental stages, providing new insights into the physiological function of SST and SSTR2 in several cell types.
Mice ; Animals ; Receptors, Somatostatin/metabolism* ; Hematopoietic Stem Cells/metabolism* ; Epithelial Cells

OBJECTIVE: To investigate the expression and its relative mechanism of hypoxia-inducible factor-1α(HIF-1α) in bone marrow(BM) of mice during G-CSF mobilization of hematopoietic stem cells (HSC) . METHODS: Flow cytometry was used to detect the proportion of Lin^-Sca-1⁺ c-kit⁺ (LSK) cells in peripheral blood of C57BL/6J mice before and after G-CSF mobilization. And the expression of HIF-1α and osteocalcin (OCN) mRNA and protein were detected by RQ-PCR and immunohistochemistry. The number of osteoblasts in bone marrow specimens of mice was counted under the microscope. RESULTS: The proportion of LSK cells in peripheral blood began to increase at day 4 of G-CSF mobilization, and reached the peak at day 5, which was significantly higher than that of control group (P<0.05). There was no distinct difference in the expression of HIF-1α mRNA between bone marrow nucleated cells and osteoblasts of steady-state mice (P=0.073), while OCN mRNA was mainly expressed in osteoblasts, which was higher than that in bone marrow nucleated cells (P=0.034). After mobilization, the expression level of HIF-1α increased, but OCN decreased, and the number of endosteum osteoblasts decreased. The change of HIF-1α expression was later than that of OCN and was consistent with the proportion of LSK cells in peripheral blood. CONCLUSION The expression of HIF-1α in bone marrow was increased during the mobilization of HSC mediated by G-CSF, and one of the mechanisms may be related to the peripheral migration of HSC induced by osteoblasts inhibition.
Mice ; Animals ; Hematopoietic Stem Cell Mobilization ; Granulocyte Colony-Stimulating Factor/pharmacology* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Mice, Inbred C57BL ; Bone Marrow Cells/metabolism* ; Osteocalcin/metabolism* ; RNA, Messenger/metabolism*

OBJECTIVE: To explore the effect of recombinant human thrombopoietin (rhTPO) on hematopoietic reconstruction in allogeneic hematopoietic stem cell transplantation (allo-HSCT) model. METHODS: The C57BL/6 mice were employed as the donors, and BALB/c mice as recipients. The bone marrow mononuclear cells of the donor mice were extracted and pretreated, which then were injected with 5×10⁶ per mouse through the tail vein of the recipient to establish an allo-HSCT model. The implantation of hematopoietic stem cells in the recipient mice was detected by flow cytometry on the 28^th day after transplantation. Next, the successfully modeled recipient mice were randomly divided into experimental group and control group. The rhTPO was injected into mice in the experimental group on the first day after transplantation, while the saline was injected into mice in the control group. Both groups were injected for 14 consecutive days. The peripheral blood and bone marrow hematopoiesis of the two groups were observed on day 1, 3, 7, 14, and 21 after transplantation. RESULTS: The expression rate of H-2K^b in the bone marrow of recipient mice was 43.85% (>20%) on the 28^th day after transplantation, which indicated that the recipient mice were successfully chimerized. Meanwhile, counts of PLTs on the day 3, 7, 14, and 21 after transplantation in the experimental group were higher than those in the control group with statistical significances (P<0.05). In addition, hematopoietic function of bone marrow was suppressed in both groups on day 1, 3 and 7 after transplantation, but hematopoietic bone marrow hyperplasia was better in the experimental group than in the control group. On day 14 and 21 after transplantation, the hematopoietic function of bone marrow in the two groups was recovered, and the experimental group showed more obvious than the control group. CONCLUSION rhTPO can effectively stimulate the production of PLTs and facilitate the recovery of white blood cells and hemoglobin after allo-HSCT, and promote hematopoietic recovery and reconstitution of bone marrow.
Humans ; Animals ; Mice ; Thrombopoietin ; Mice, Inbred C57BL ; Hematopoietic Stem Cell Transplantation ; Hematopoietic Stem Cells ; Bone Marrow ; Recombinant Proteins ; Mice, Inbred BALB C

Objective: To observe the effect of platelets on hematopoietic stem cell (HSCs) implantation in mice with radiation-induced bone marrow injury and bone marrow transplantation models. Methods: ①Male C57BL/6 mice were divided into a single irradiation group and a radiation infusion group after receiving (60)Co semimyeloablative irradiation for 18-10 weeks. The irradiation infusion group received 1×10(8) platelets expressing GFP fluorescent protein. ② The allogeneic bone marrow transplantation model was established. The experimental groups included the simple transplantation group (BMT) and the transplantation infusion group (BMT+PLT). The BMT group was infused through the tail vein only 5 × 10(6) bone marrow cells, the BMT+PLT group needs to be infused with bone marrow cells at the same time 1× 10(8) platelets. ③ Test indicators included peripheral blood cell and bone marrow cell counts, flow cytometry to detect the proportion of hematopoietic stem cell (HSC) and hematopoietic progenitor cells, bone marrow cell proliferation and apoptosis, and pathological observation of vascular niche damage and repair. Results: ①On the 3rd, 7th, 14(th), and 21st days after irradiation, the bone marrow cell count of the infusion group was higher than that in the single irradiation group (P<0.05), and the peripheral blood cell count was also higher. A statistically significant difference was found between the white blood cell count on the 21st day and the platelet count on the 7th day (P<0.05). In the observation cycle, the percentage of bone marrow cell proliferation in the infusion group was higher, while the percentage of apoptosis was lower. ② The results of bone tissue immunofluorescence after irradiation showed that the continuity of hematopoietic niche with red fluorescence was better in the irradiation infusion group. ③The chimerism percentage in the BMT+PLT group was always higher than that in the BMT group after transplantation.④ The BMT+PLT group had higher bone marrow cell count and percentage of bone marrow cell proliferation on the 7th and 28th day after transplantation than that in the BMT group, and the percentage of bone marrow cell apoptosis on the 14th day was lower than that in the BMT group (P<0.05). After the 14th day, the percentage of stem progenitor cells in the bone marrow cells of mice was higher than that in the BMT group (P<0.05). ⑤The immunohistochemical results of bone marrow tissue showed that the continuity of vascular endothelium in the BMT+PLT group was better than that in the BMT group. Conclusion: Platelet transfusion can alleviate the injury of vascular niche, promotes HSC homing, and is beneficial to hematopoietic reconstruction.
Mice ; Animals ; Bone Marrow Transplantation ; Bone Marrow ; Mice, Inbred C57BL ; Hematopoietic Stem Cells ; Bone Marrow Diseases ; Hematopoietic Stem Cell Transplantation ; Mice, Inbred BALB C

OBJECTIVE: To investigate the effect and relative mechanism of Recombinant Human Thrombopoietin (rhTPO) on long-term hematopoietic recovery in mice with acute radiation sickness. METHODS: Mice were intramuscularly injected with rhTPO (100 μg/kg) 2 hours after total body irradiation with ⁶⁰Co γ-rays (6.5 Gy). Moreover, six months after irradiation, peripheral blood, hematopoietic stem cells (HSC) ratio, competitive transplantation survival rate and chimerization rate, senescence rate of c-kit⁺ HSC, and p16 and p38 mRNA expression of c-kit⁺ HSC were detected. RESULTS: Six months after 6.5 Gy γ-ray irradiation, there were no differences in peripheral blood white blood cells, red blood cells, platelets, neutrophils and bone marrow nucleated cells in normal group, irradiated group and rhTPO group (P>0.05). The proportion of hematopoietic stem cells and multipotent progenitor cells in mice of irradiated group was significantly decreased after irradiation (P<0.05), but there was no significant changes in rhTPO group (P>0.05). The counts of CFU-MK and BFU-E in irradiated group were significantly lower than that in normal group, and rhTPO group was higher than that of the irradiated group(P<0.05). The 70 day survival rate of recipient mice in normal group and rhTPO group was 100%, and all mice died in irradiation group. The senescence positive rates of c-kit⁺ HSC in normal group, irradiation group and rhTPO group were 6.11%, 9.54% and 6.01%, respectively (P<0.01). Compared with the normal group, the p16 and p38 mRNA expression of c-kit⁺ HSC in the irradiated mice were significantly increased (P<0.01), and it was markedly decreased after rhTPO administration (P<0.01). CONCLUSION The hematopoietic function of mice is still decreased 6 months after 6.5 Gy γ-ray irradiation, suggesting that there may be long-term damage. High-dose administration of rhTPO in the treatment of acute radiation sickness can reduce the senescence of HSC through p38-p16 pathway and improve the long-term damage of hematopoietic function in mice with acute radiation sickness.
Humans ; Mice ; Animals ; Thrombopoietin/metabolism* ; Hematopoietic Stem Cells ; Blood Platelets ; Recombinant Proteins/therapeutic use* ; Radiation Injuries ; RNA, Messenger/metabolism*

OBJECTIVE: To explore the chronic injury and its possible mechanism of ionizing radiation on multipotent hematopoietic progenitor cells (MPPs) by determining the related indicators of MPPs in bone marrow of mice post-radiation. METHODS: Sixteen C57BL/6 adult mice were randomly divided into normal control and irradiation groups, 8 mice in each group. The mice in irradiation group were exposed to 6 Gy X-ray. The proportion of bone marrow MPPs, their apoptosis and proliferation 2 months after irradiation were detected by flow cytometry. Mitochondrial activity and levels of reactive oxygen species (ROS) in each MPPs population were detected by Mitotracker Red and DCFDA probes, and the senescent state of MPPs in the bone marrow was analyzed. RESULTS: Ionizing radiation could reduce the proportion of MPPs in mouse bone marrow. The proportions and numbers of MPP1, MPP3 and MPP4 in the bone marrow were significantly decreased after whole-body irradiation with 6 Gy X-ray (P<0.05). In addition, radiation significantly reduced the colony-forming capacity of MPPs in bone marrow (P<0.05), the proportions of apoptotic cells in the MPP1 and MPP4 cell populations increased significantly in the bone marrow (P<0.05). The activity of mitochondria was significantly reduced in the bone marrow MPP2, MPP3 and MPP4 cell populations compared with that of the control group (P<0.05). It was also found that the radiation could significantly increase the ROS levels of MPPs in bone marrow, and the content of ROS in the MPP2, MPP3 and MPP4 cell population of the bone marrow was significantly increased(P<0.05). The senescent cells ratios of MPP1, MPP3 and MPP4 cells in the bone marrow after irradiation were significantly higher than those in the control group (P<0.05). CONCLUSION Ionizing radiation can cause chronic MPPs damage in mice, which is closely associated with persistent oxidative stress, cells apoptosis, and cellular senescence.
Mice ; Animals ; Bone Marrow ; Reactive Oxygen Species ; Mice, Inbred C57BL ; Hematopoietic Stem Cells ; Whole-Body Irradiation ; Radiation, Ionizing ; Bone Marrow Cells

OBJECTIVE: To explore the clinical characteristics, treatment, and prognosis of patients with blastic plasmacytoid dendritic cell neoplasm(BPDCN). METHODS: Clinical data of 5 patients diagnosed with BPDCN in Wuhan First Hospital and Wuhan Tongji Hospital from June 2016 to November 2021 were retrospectively analyzed. RESULTS: Among the 5 patients, 3 were male and 2 were female, with a median age of 28(10-52) years old. Four patients showed obvious skin damage at the initial diagnosis; the other one showed clinical manifestations of acute leukemia rather than obvious skin damage at the initial diagnosis, but infiltrated skin when the disease relapsed after treatment. Other infiltration sites of lesions included bone marrow (2/5), peripheral blood (2/5), lymph nodes (3/5), liver and spleen (2/5). All patients had no clinical manifestation of central nervous system infiltration. Tumor cell specific immune markers CD4, CD56, CD123 were all positive, and the median Ki-67 index was 70%. TET2, ASXL1 and NRAS gene mutations were found respectively in 3 patients by next-generation sequencing technique (NGS). ALL-like, AML-like and invasive NK/T cell lymphoma-like first-line induction chemotherapy regimens were used for the patients. One patient died of severe complications during the early stage of chemotherapy, 3 patients were evaluated as CR, and 1 patient was evaluated as PR. 2 patients were recurred and progressed after induction of chemotherapy, and one of them was evaluated as CR after re-treatment. One patient received autologous hematopoietic stem cell transplantation (auto-HSCT) and got long-term survival (OS 87 months). 3 patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT), of which one died of transplantation related complications, and 2 cases survived. The median follow-up time of 4 patients with evaluable efficacy was 28.5(9-84) months, the median OS time was 31.5(10-87) months. CONCLUSION BPDCN is a highly heterogeneous malignant tumor with a poor prognosis. HSCT, especially allo-HSCT can significantly improve the prognosis of BPDCN patients.
Humans ; Male ; Female ; Adult ; Middle Aged ; Retrospective Studies ; Leukemia/pathology* ; Hematopoietic Stem Cell Transplantation ; Prognosis ; Myeloproliferative Disorders ; Skin Neoplasms/pathology* ; Acute Disease ; Dendritic Cells

OBJECTIVE: To investigate the correlation between plasmacytoid dendritic cell (pDC) dose in grafts and the occurrence of cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The clinical data of 80 children who received allo-HSCT in Children's Hospital of Soochow University from August 20, 2020 to June 11, 2021 were retrospectively analyzed. Proportions of DC subsets and T-cell subsets in grafts were detected by flow cytometry in order to calculate infused cell dose of each cell. Weekly monitoring of CMV-DNA copies in peripheral blood for each child were performed after transplantation. The last follow-up date was December 31, 2021. RESULTS: All the children gained hematopoietic reconstitution. CMV infection was observed in 51 children (63.8%±5.4%) within the first 100 days after transplantation, including 2 cases developing CMV disease. Univariate analysis indicated that infused doses of DC and pDC were significantly associated with CMV infection within 100 days after allo-HSCT (P <0.05). Multivariate analysis indicated that a high dose infusion of pDC was an independent protective factor for CMV infection within 100 days after allo-HSCT (P <0.05). By the end of follow-up, 7 children died of transplantation-related complications, including 2 deaths from CMV disease, 2 deaths from extensive chronic graft-versus-host disease, and 3 deaths from capillary leak syndrome. The overall survival rate was 91.2%. CONCLUSION The pDC in grafts may be associated with early infection of CMV after allo-HSCT, while a high infused pDC dose may serve as a protective factor for CMV infection after transplantation.
Child ; Humans ; Retrospective Studies ; Graft vs Host Disease/complications* ; Cytomegalovirus Infections ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Dendritic Cells

The homing and engraftment of hematopoietic stem cells (HSC) into bone marrow is the first critical step for successful clinical hematopoietic stem cell transplantation (HSCT). SDF-1 / CXCR4 is considered to be a very promising target to promote HSC homing. In recent years, with the in-depth research on the HSC homing, a variety of new strategies for promoting HSC homing and engraftment have been explored, such as nuclear hormone receptor, histone deacetylase inhibitor, prostaglandin and metabolic regulation, so as to increase the success rate of HSCT and improve the survival of patients. In this review, the recent research advances in the mechanism of HSC homing and strategies to promote HSC homing and engraftment were summarized and discussed.
Humans ; Hematopoietic Stem Cells/physiology* ; Bone Marrow ; Hematopoietic Stem Cell Transplantation ; Gene Expression Regulation ; Prostaglandins/metabolism*

Capillary leak syndrome (CLS) is a clinical syndrome characterized by impairment of vascular endothelial barrier function, increased vascular permeability, and reversible systemic edema. It is one of the early fatal complications after hematopoietic stem cell transplantation. So far, the exact pathogenesis of CLS has not been elucidated, and the diagnostic criteria and treatment methods have not been unified. At present, it is believed that the fundamental cause of CLS is hypercytokinemia, and the core factor is high permeability of vascular endothelial cells. According to the clinical manifestations, the natural course of CLS can be divided into prodrome, leakage and recovery stages. As far as treatment is concerned, symptomatic and supportive treatment is dominant according to different characteristics of each stage. In this review, the pathogenesis, clinical manifestations, diagnosis and treatment of hematopoietic stem cell transplant-associated CLS were briefly summarized.
Humans ; Capillary Leak Syndrome/diagnosis* ; Endothelial Cells ; Hematopoietic Stem Cell Transplantation/adverse effects*