A comparative study of platelet storage lesion in platelet-rich plasma under cryopreservation.

Platelet-rich plasma (PRP) has significant potential for various applications and holds clinical value in regenerative medicine. Cryopreservation is used to extend the preservation period of PRP, facilitating its clinical application. However, the potential negative effects of long-term cryopreservation on platelet storage lesion are still uncertain. In this study, PRP was stored at - 30 °C or - 80 °C. Platelet count, apoptosis, reactive oxygen species (ROS) content, and CD62P expression were assessed on the 14th and 28th days. The study also evaluated platelet mitochondria morphology and function, serotonin (5-HT) secretion by platelets, and the inflammatory activating effect of cryopreserved platelets in PRP. The results showed that there were no significant differences in platelet count, the content of 5-HT, and inflammatory effects between fresh PRP and PRP cryopreserved at both - 30 °C and - 80 °C. However, there was an increase in ROS level, apoptosis, and CD62P level after cryopreservation at both temperatures. Additionally, the levels of ROS, apoptosis, and CD62P in platelets were similar after storage at - 30 °C and - 80 °C. The main difference observed was that the morphology and function of mitochondria were severely damaged after storage at - 30 °C, while they were less affected at - 80 °C. Based on these findings, it can be concluded that storing PRP at - 80 °C is more suitable for achieving a better therapeutic effect in clinical applications, but cryopreservation could not replace the current standard.

Dysregulated hemolysin liberates bacterial outer membrane vesicles for cytosolic lipopolysaccharide sensing.

Inflammatory caspase-11/4/5 recognize cytosolic LPS from invading Gram-negative bacteria and induce pyroptosis and cytokine release, forming rapid innate antibacterial defenses. Since extracellular or vacuole-constrained bacteria are thought to rarely access the cytoplasm, how their LPS are exposed to the cytosolic sensors is a critical event for pathogen recognition. Hemolysin is a pore-forming bacterial toxin, which was generally accepted to rupture cell membrane, leading to cell lysis. Whether and how hemolysin participates in non-canonical inflammasome signaling remains undiscovered. Here, we show that hemolysin-overexpressed enterobacteria triggered significantly increased caspase-4 activation in human intestinal epithelial cell lines. Hemolysin promoted LPS cytosolic delivery from extracellular bacteria through dynamin-dependent endocytosis. Further, we revealed that hemolysin was largely associated with bacterial outer membrane vesicles (OMVs) and induced rupture of OMV-containing vacuoles, subsequently increasing LPS exposure to the cytosolic sensor. Accordingly, overexpression of hemolysin promoted caspase-11 dependent IL-18 secretion and gut inflammation in mice, which was associated with restricting bacterial colonization in vivo. Together, our work reveals a concept that hemolysin promotes noncanonical inflammasome activation via liberating OMVs for cytosolic LPS sensing, which offers insights into innate immune surveillance of dysregulated hemolysin via caspase-11/4 in intestinal antibacterial defenses.

Platelets directly regulate DNA damage and division of Staphylococcus aureus.

Platelets (PLTs) are classically used in the clinical setting to maintain hemostasis. Recent evidence supports important roles for PLTs in host inflammatory and immune responses, and PLT-rich plasma has been demonstrated to inhibit the growth of bacteria in vitro and in vivo; however, few studies have examined whether PLTs can inhibit bacterial growth directly, and related mechanisms have not been elucidated further. Accordingly, in this study, we evaluated the effects of PLTs on bacterial growth. We washed and purified PLTs from peripheral blood, then confirmed that PLTs significantly inhibited the growth of Staphylococcus aureus when cocultured in vitro. Moreover, PLTs damaged DNA and blocked cell division in S. aureus. During coculture, PLT-derived TGF-ß1 was dramatically down-regulated compared with that in PLT culture alone, and the addition of TGF-ß1 to the coculture system promoted the inhibition of PLTs on S. aureus. Analysis of a murine S. aureus infection model demonstrated that the depletion of PLTs exacerbated the severity of infection, whereas the transfusion of PLTs alleviated this infection. Our observations demonstrate that PLTs could directly inhibit the growth of S. aureus by damaging DNA and blockage cell division, and that PLT-derived TGF-ß1 may play an important role in this machinery.-Xu, J., Yi, J., Zhang, H., Feng, F., Gu, S., Weng, L., Zhang, J., Chen, Y., An, N., Liu, Z., An, Q., Yin, W., Hu, X. Platelets directly regulate DNA damage and division of Staphylococcus aureus.

Sca-1(+) mesenchymal stromal cells inhibit splenic marginal zone B lymphocytes commitment through Caspase-3.

Mesenchymal stromal cells (MSCs) have been characterized as an important component of hematopoietic niche, which are capable of modulating the immune system through interaction with a wide range of immune cells. Marginal zone B cells, one main type of mature B lymphocytes, play a central role in eliciting antibody response against pathogens. However, how MSCs and its subpopulations regulate marginal zone B cells commitment is unknown yet. In this study, we assessed the contribution of Sca-1(+) MSCs on marginal zone B cells commitment. Our results showed that Sca-1(+) MSCs inhibit the commitment of marginal zone B lymphocytes. The inhibition was exerted through lowered Caspase-3 expression. Furthermore, we found marginal zone B lymphocytes in spleen of Caspase-3 knockout mice decreased and Caspase-3 knockout Sca-1(+) MSCs accounted for the MZB lymphocytes decrease. In conclusion, our investigation provided clues about Sca-1(+) MSCs regulation on the commitment of marginal zone B cells through Caspase-3 gene.

Supernatant of platelet-Klebsiella pneumoniae coculture induces apoptosis-like death in Klebsiella pneumoniae.

Multidrug-resistant Klebsiella pneumoniae strains, especially carbapenem-resistant K. pneumoniae, have become a rapidly emerging crisis worldwide, greatly limiting current therapeutic options and posing new challenges to infection management. Therefore, it is imperative to develop novel and effective biological agents for the treatment of multidrug-resistant K. pneumoniae infections. Platelets play an important role in the development of inflammation and immune responses. The main component responsible for platelet antibacterial activity lies in the supernatant stimulated by gram-positive bacteria. However, little research has been conducted on the interaction of gram-negative bacteria with platelets. Therefore, we aimed to explore the bacteriostatic effect of the supernatant derived from platelet-K. pneumoniae coculture and the mechanism underlying this effect to further assess the potential of platelet-bacterial coculture supernatant. We conducted this study on the gram-negative bacteria K. pneumoniae and CRKP and detected turbidity changes in K. pneumoniae and CRKP cultures when grown with platelet-K. pneumoniae coculture supernatant added to the culture medium. We found that platelet-K. pneumoniae coculture supernatant significantly inhibited the growth of K. pneumoniae and CRKP in vitro. Furthermore, transfusion of platelet-K. pneumoniae coculture supernatant alleviated the symptoms of K. pneumoniae and CRKP infection in a murine model. Additionally, we observed apoptosis-like changes, such as phosphatidylserine exposure, chromosome condensation, DNA fragmentation, and overproduction of reactive oxygen species in K. pneumoniae following treatment with the supernatant. Our study demonstrates that the platelet-K. pneumoniae coculture supernatant can inhibit K. pneumoniae growth by inducing an apoptosis-like death, which is important for the antibacterial strategies development in the future.IMPORTANCEWith the widespread use of antibiotics, bacterial resistance is increasing, and a variety of multi-drug resistant Gram-negative bacteria have emerged, which brings great challenges to the treatment of infections caused by Gram-negative bacteria. Therefore, finding new strategies to inhibit Gram-negative bacteria and even multi-drug- resistant Gram-negative bacteria is crucial for treating infections caused by Gram-negative bacteria, improving the abuse of antibiotics, and maintaining the balance between bacteria and antibiotics. K. pneumoniae is a common clinical pathogen, and drug-resistant CRKP is increasingly difficult to cure, which brings great clinical challenges. In this study, we found that the platelet-K. pneumoniae coculture supernatant can inhibit K. pneumoniae growth by inducing an apoptosis-like death. This finding has inspired the development of future antimicrobial strategies, which are expected to improve the clinical treatment of Gram-negative bacteria and control the development of multidrug-resistant strains.

Mac1+/Gr1+ cells contribute to transfusion-related acute lung injury.

Transfusion-related acute lung injury (TRALI) is a serious complication associated with blood transfusion and can cause transfusion associated fatalities. Both antibody dependent and non-dependent mechanisms are involved in TRALI, as proposed over the past years. Nonetheless, many details of the immune cells involved in TRALI, particularly the Mac1(+)/Gr1(+) cells from donors, are not fully understood yet. Here we used an in vitro transwell system and a mouse model to study the role of donor leukocytes, present in the donor material, in the occurrence of TRALI reactions. We found that there is a number of immature myeloid cells with Mac1(+)/Gr1(+) phenotype present in the red blood cell (RBC) products, when prepared by regular methods. We found that murine Mac1(+)/Gr1(+) cells from stored RBC products display an elevated MHC I and CD40 expression, as well as an enhanced tumor necrosis factor alpha(TNF-α), interlukin-6(IL-6) and macrophage inflammatory protein 2 (MIP-2) secretion. When tested in a transwell endothelial migration assay, Mac1(+)/Gr1(+) cells showed a significant capability to cross the endothelial barrier. In vivo investigation demonstrated that compared to the purified RBC transfusion, more murine Mac1(+)/Gr1(+) cells from the regular method produced RBC sequestered in the lung, which associated to shorter survival. Taken together, these data suggest that donor derived Mac1(+)/Gr1(+) cells can play a significant role in TRALI reactions, and that reduction of Mac1(+)/Gr1(+) cell number from RBC products is necessary to control the severity of TRALI reactions in clinic.

Platelet-Derived Mitochondria Attenuate 5-FU-Induced Injury to Bone-Associated Mesenchymal Stem Cells.

Background: Myelosuppression is a common condition during chemotherapy. Bone-associated mesenchymal stem cells (BA-MSCs) play an essential role in the composition of the hematopoietic microenvironment and support hematopoietic activity. However, chemotherapy-induced damage to BA-MSCs is rarely studied. Recent studies have shown that platelets promote the wound-healing capability of MSCs by mitochondrial transfer. Therefore, this study is aimed at investigating the chemotherapy-induced damage to BA-MSCs and the therapeutic effect of platelet-derived mitochondria. Material/Methods. We established in vivo and in vitro BA-MSC chemotherapy injury models using the chemotherapy agent 5-fluorouracil (5-FU). Changes in the mitochondrial dynamics were detected by transmission electron microscopy, and the expression of mitochondrial fusion and fission genes was analyzed by qRT-PCR. In addition, mitochondrial functions were also explored by flow cytometry and luminometer. Platelet-derived mitochondria were incubated with 5-FU-damaged BA-MSCs to repair the injury, and BA-MSC functional changes were examined to assess the therapy efficacy. The mechanism of treatment was explored by studying the expression of mitochondrial fission and fusion genes and hematopoietic regulatory factor genes in BA-MSCs. Results: Stimulation with 5-FU increased the apoptosis and suppressed cell cycle progression of BA-MSCs both in vivo and in vitro. In addition, 5-FU chemotherapy inhibited the hematopoietic regulatory ability and disrupted the mitochondrial dynamics and functions of BA-MSCs. The mitochondrial membrane potential and ATP content of 5-FU-injured BA-MSCs were decreased. Interestingly, when platelet-derived mitochondria were transferred to BA-MSCs, the 5-FU-induced apoptosis was alleviated, and the hematopoietic regulatory ability of 5-FU-injured BA-MSCs was effectively improved by upregulating the expression of mitochondrial fusion genes and hematopoietic regulatory factor genes. Conclusion: BA-MSCs were severely damaged by 5-FU chemotherapy both in vivo and in vitro. Meanwhile, platelet-derived mitochondria could attenuate the 5-FU-induced injury to BA-MSCs, which provides future research directions for exploring the treatment strategies for chemotherapy-injured BA-MSCs and establishes a research basis for related fields.

NLRP3 inflammasome inhibition of OP9 cells enhance therapy for inflammatory bowel disease.

Mesenchymal stem cells (MSCs) are becoming more popular in therapy. Therefore, in-depth studies on mesenchymal stem cells in therapy are urgently needed. However, the difficulty in culturing and propagating MSCs in vitro complicates potential studies on MSCs in a murine model. OP9 cells are a stromal cell line from mouse bone marrow, which have similar characteristics and functions to MSCs and can maintain their original characteristics. Because of these properties, OP9 cells have become a suitable substitute for research on MSCs. Previously, we have found that MSCs can cure inflammatory bowel disease in mice. In this study, we aimed to investigate whether OP9 cells can functionally regulate and alleviate inflammatory diseases. We evaluated the therapeutic effect of OP9 cells in the mouse model of inflammatory bowel disease and found OP9 cells were able to ameliorate inflammatory bowel disease. We explored the existence of NLRP3 inflammasome in OP9 cells, and showed better therapeutic effects when the NLRP3 inflammasome was suppressed. Thus, OP9 cell line is similar to MSCs in characteristic and function, and is an ideal substitute for MSCs research. The preliminary exploration of the inflammasome system in OP9 cells lays a theoretical and methodological foundation for further study of MSCs.

A novel coumarin derivative DBH2 inhibits proliferation and induces apoptosis of chronic myeloid leukemia cells.

With the development of tyrosine kinase inhibitor (TKI) resistance, finding the novel effective chemotherapeutic agent is of seminal importance for chronic myelogenous leukemia (CML) treatment. This study aims to find the effective anti-leukemic candidates and investigate the possible underlying mechanism. We synthesized the novel coumarin derivatives and evaluated their anti-leukemic activity. Cell viability assay revealed that compound DBH2 exhibited the potent inhibitory activity on the proliferation of CML K562 cells and TKI resistant K562 cells. Morphological observation and flow cytometry confirmed that DBH2 could selectively induce cell apoptosis and cell cycle arrest at G2/M phase of the K562 cells, which was further confirmed on the bone marrow cells from CML transgenic model mice and CD34+ bone marrow leukemic cells from CML patients. Treatments of DBH2 in combination with imatinib could prolong the survival rate of SCL-tTA-BCR/ABL transgenic model mice significantly. Quantitative RT-PCR revealed that DBH2 inhibited the expression of STAT3 and STAT5 in K562 cells, and caspase-3 knockout alleviated the DBH2 induced apoptosis. Furthermore, DBH2 could induce the expression of PARP1 and ROCK1 in K562 cells, which may play the important role in caspase-dependent apoptosis. Our results concluded that coumarin derivative DBH2 serves as a promising candidate for the CML treatment, especially in the combination with imatinib for the TKI resistant CML, and STAT/caspase-3 pathway was involved in the molecular mechanism of anti-leukemic activity of DBH2.

[High expression of P-selectin (CD62P) after platelet activation in vitro inhibits bacterial proliferation and induces apoptosis-like changes].

Objective To compare the expression level of P-selectin (CD62P) on platelets surface under the stimulation of Staphylococcus aureus (SA) and Escherichia coli (E.coli), explore the inhibitory effects of platelets on the their proliferation, and further investigate the molecular mechanism by which platelets inhibit the proliferation of bacteria. Methods 106 CFU/mL SA and E.coli were co-cultured with 2×1011/L purified platelets, and the A600 values of the two groups were detected; The CD62P of platelets was detected by flow cytometry after platelets co-cultured with SA and E.coli for 2 hours and 4 hours. The platelet factor 4 (PF4) released by platelets was detected by ELISA; After co-cultured with SA and E.coli for 12 hours, the proliferation, phosphatidylserine (PS) eversion and cell membrane potential of SA and E.coli were analyzed by flow cytometry. Results After platelets co-cultured with SA and E.coli for 6 hours, the turbidity of SA decreased significantly and the turbidity of E.coli showed a slight decrease. Compared with the control group, the counts of bacterial plates decreased after two kinds of bacteria co-cultured with platelets. After co-cultured with SA and E.coli for 2 hours and 4 hours, the CD62P levels of platelets increased. In particular, the CD62P level of platelets co-cultured with SA was significantly higher than that of platelets co-cultured with E.coli. The release of intracellular protein PF4 of platelet increased significantly after bacteria stimulation. The proliferation rate of SA and E.coli decreased after co-cultured with platelets, and SA and E.coli exhibited PS eversion and depolarization of cell membrane potential. Conclusion High expression of CD62P inhibits the proliferation and induces apoptotic changes of SA and E.coli after platelets activation in vitro, and the inhibitory effect of platelets on SA was better than that of E.coli.

Caspase-3/NLRP3 signaling in the mesenchymal stromal niche regulates myeloid-biased hematopoiesis.

BACKGROUND: The fate of hematopoietic stem cells (HSCs) is determined by a complex regulatory network that includes both intrinsic and extrinsic signals. In the past decades, many intrinsic key molecules of HSCs have been shown to control hematopoiesis homeostasis. Non-hematopoietic niche cells also contribute to the self-renewal, quiescence, and differentiation of HSCs. Mesenchymal stromal cells (MSCs) have been identified as important components of the niche. However, the regulatory role of MSCs in hematopoiesis has not been fully understood. METHODS: Caspase-3 and NLRP3 gene knockout mice were generated respectively, and hematopoietic development was evaluated in the peripheral circulation and bone marrow by flow cytometry, colony formation assay, and bone marrow transplantation. Bone-associated MSCs (BA-MSCs) were then isolated from gene knockout mice, and the effect of Caspase-3/NLRP3 deficient BA-MSCs on hematopoiesis regulation was explored in vivo and ex vivo. RESULTS: We report that Caspase-3 deficient mice exhibit increased myelopoiesis and an aberrant HSC pool. Ablation of Caspase-3 in BA-MSCs regulates myeloid lineage expansion by altering the expression of hematopoietic retention cytokines, including SCF and CXCL12. Interestingly, NLRP3 gene knockout mice share phenotypic similarities with Caspase-3 deficient mice. Additionally, we found that NLRP3 may play a role in myeloid development by affecting the cell cycle and apoptosis of hematopoietic progenitors. CONCLUSIONS: Our data demonstrate that the Caspase-3/NLRP3 signaling functions as an important regulator in physiological hematopoiesis, which provides new insights regarding niche signals that influence hematopoiesis regulation in the bone marrow.

NLRP3 inflammasome of renal tubular epithelial cells induces kidney injury in acute hemolytic transfusion reactions.

BACKGROUND: Blood transfusion, a common basic supporting therapy, can lead to acute hemolytic transfusion reaction (AHTR). AHTR poses a great risk to patients through kidney function damage in a short time. Previous reports found that heme from destroyed red blood cells impaired kidney function, and NLR family pyrin domain containing 3 (NLRP3) inflammasome was augmented in case of kidney injury. However, the detailed mechanism regarding whether NLRP3 inflammasome is involved in kidney function injury in AHTR is not fully understood yet. METHODS: Hemolysis models were established by vein injection with human blood plasma or mouse heme from destroyed red blood cells. The injured renal tubular epithelial cells (RTECs) were evaluated by tubular damage markers staining in hemolysis models and in primary RTECs in vitro. The activation of NLRP3 inflammasome in RTECs by hemes was investigated by Western blot, ELISA, scanning electron microscopy, immunofluorescent staining, flow cytometry, and hemolysis models. NLRP3 gene knockout mice were employed to confirm these observations in vitro and in vivo. The binding between a novel inhibitor (66PR) and NLRP3 was affirmed by molecule docking and co-immunoprecipitation. The rescue of 66PR on kidney function impairment was explored in murine hemolysis models. RESULTS: We found that heme could activate NLRP3 inflammasome in RTECs to induce kidney function injury. NLRP3 gene knockout could prevent the damage of RTECs caused by hemes and recover kidney function in AHTR. Moreover, NLRP3 inflammasome chemical inhibitor, 66PR, could bind to NLRP3 protein and inhibit inflammasome activation in RTECs, which consequently relieved the injury of RTECs caused by hemes, and alleviated kidney function damage in the AHTR model. CONCLUSIONS: Hemes could activate NLRP3 inflammasome in RTECs, and a novel NLRP3 inflammasome inhibitor named 66PR relieved kidney function damage in AHTR. Our findings provided a new possible strategy to treat kidney function failure in AHTR.

Anti-HCV reactive volunteer blood donors distribution character and genotypes switch in Xi'an, China.

HCV is prevailed in the world as well as in China. Blood transfusion is one of the most common transmission pathways of this pathogen. Although data of HCV infection character were reported during the past years, anti-HCV reactive profile of China donors was not fully clear yet. Furthermore, infection progress was found related to the HCV genotype. Different genotype led to different efficacy when interferon was introduced into HCV therapy. Here we provided character data of HCV infection in China blood donors from the year of 2000 to 2009. The infection rate in local donors was lower than general population and descended from 0.80% to 0.40% or so in recent years. About 83% HCV strains were categorized into genotypes 1b and 2a. But 1b subtype cases climbed and 2a subtype cases decreased. The current study threw more light on HCV infection of blood donors in China, at least in the Northern region.

Immune response to fused core protein of hepatitis C virus and truncated tetanus toxin peptides in mice.

Because no vaccine or effective therapy is available, thousands of people with HCV have died in recent years. Cytotoxic T lymphocytes (CTLs) play a critical role in the host cellular immune response against HCV. CTL epitopes in HCV core protein have been identified and used in vaccine development. T helper epitopes could promote cytokine secretion and antibody production to fight HCV. Tetanus toxin, an immunogen with many T helper epitopes, was once used in HBV therapeutic vaccine design. Here, eukaryotic and prokaryotic expression vectors were constructed to express truncated fragments of tetanus toxin and core genes of HCV. HLAA2.1 transgenic mice were inoculated with a recombinant plasmid vehicle with these two heterogenic gene fragments, and this augmented the titres of antibody against HCV. Antigen-specific lymphocyte proliferation, Th1 and Th2 cytokine levels and the number of lysed cells were markedly increased in the combined immunization group compared to controls. These findings provide new insights into a potential role for T helper epitopes from tetanus toxin combined with protein from the HCV core gene, which has numerous CTL epitopes. This design strategy may aid in the development of new vaccines against HCV.

Hepatitis B virus genotypes and evolutionary profiles from blood donors from the northwest region of China.

Hepatitis B virus (HBV) is prevalent in China and screening of blood donors is mandatory. Up to now, ELISA has been universally used by the China blood bank. However, this strategy has sometimes failed due to the high frequency of nucleoside acid mutations. Understanding HBV evolution and strain diversity could help devise a better screening system for blood donors. However, this kind of information in China, especially in the northwest region, is lacking. In the present study, serological markers and the HBV DNA load of 11 samples from blood donor candidates from northwest China were determined. The HBV strains were most clustered into B and C genotypes and could not be clustered into similar types from reference sequences. Subsequent testing showed liver function impairment and increasing virus load in the positive donors. This HBV evolutionary data for China will allow for better ELISA and NAT screening efficiency in the blood bank of China, especially in the northwest region.

Mesenchymal Stromal Cells Directly Promote Inflammation by Canonical NLRP3 and Non-canonical Caspase-11 Inflammasomes.

Mesenchymal stromal cells (MSCs) based therapy is a promising approach to treat inflammatory disorders. However, therapeutic effect is not always achieved. Thus the mechanism involved in inflammation requires further elucidation. To explore the mechanisms by which MSCs respond to inflammatory stimuli, we investigated whether MSCs employed inflammasomes to participate in inflammation. Using in vitro and in vivo models, we found that canonical NLRP3 and non-canonical caspase-11 inflammasomes were activated in bone-associated MSCs (BA-MSCs) to promote the inflammatory response. The NLRP3 inflammasome was activated to mainly elicit IL-1ß/18 release, whereas the caspase-11 inflammasome managed pyroptosis. Furthermore, we sought a small molecule component (66PR) to inhibit the activation of inflammasomes in BA-MSCs, which consequently improved their survival and therapeutic potential in inflammation bowel diseases. These current findings indicated that MSCs themselves could directly promote the inflammatory response by an inflammasome-dependent pathway. Our observations suggested that inhibition of the proinflammatory property may improve MSCs utilization in inflammatory disorders.

Melanoma-Induced Anemia Could be Rescued by Sca-1+ Mesenchymal Stromal Cells in Mice.

The intrinsic basis of cancer-related anemia (CRA) is erythropoiesis disorder, which is a common complication of cancer and exerts a negative influence on the life quality of cancer patients. Cell therapy using mesenchymal stromal cells (MSCs) is considered as a promising method in cancer treatment. Furthermore, MSCs have been used to cure few type of anemia and be considered as a potential strategy to recover anemia radically. However, none reports its application in CRA treatment. In CRA model mice, we found that the number of lin-c-kit+Sca-1+ and Sca-1+ MSCs was decreased. And CRA resulted in an increased number of proerythroblasts and basophilic erythroblasts and decreased number of orthochromatic erythroblasts. Furthermore, in CRA model mice transplanted with Sca-1+ MSCs and MSCs, the levels of red blood cell count and Hb in peripheral blood were obviously increased. And the accumulation of proerythroblasts and basophilic erythroblasts was inhibited. In addition, the expression patterns of GATA-1 and GATA-2, which is pivotal to anemia, were remarkably recovered. Our results demonstrated that either MSCs or its subpopulation could effectively recover CRA erythropoiesis through GATA-1/GATA-2 signaling, which outstrips the traditional symptomatic therapy.

Mesenchymal stromal cells can be applied to red blood cells storage as a kind of cellular additive.

During storage in blood banks, red blood cells (RBCs) undergo the mechanical and metabolic damage, which may lead to the diminished capacity to deliver oxygen. At high altitude regions, the above-mentioned damage may get worse. Thus, more attention should be paid to preserve RBCs when these components need transfer from plain to plateau regions. Recently, we found that mesenchymal stromal cells (MSCs) could rescue from anemia, and MSCs have been demonstrated in hematopoietic stem cells (HSCs) transplantation to reconstitute hematopoiesis in vivo by us. Considering the functions and advantages of MSCs mentioned above, we are trying to find out whether they are helpful to RBCs in storage duration at high altitudes. In the present study, we first found that mice MSCs could be preserved in citrate phosphate dextrose adenine-1 (CPDA-1) at 4 ± 2°C for 14 days, and still maintained great viability, even at plateau region. Thus, we attempted to use MSCs as an available supplement to decrease RBCs lesion during storage. We found that MSCs were helpful to support RBCs to maintain biochemical parameters and kept RBCs function well on relieving anemia in an acute hemolytic murine model. Therefore, our investigation developed a method to get a better storage of RBCs through adding MSCs, which may be applied in RBCs storage as a kind of cellular additive into preservation solution.

Sca1(+) mesenchymal stromal cells inhibit graft-versus-host disease in mice after bone marrow transplantation.

Mesenchymal stromal cells (MSCs) have therapeutic potential for the prevention and treatment of graft-versus-host disease (GVHD). However, MSCs comprise several subpopulations, which have not been individually assessed for their role in GVHD suppression. In this study, we assessed the immunosuppressive effect of bone-related Sca1(+) MSCs on acute GVHD in a MHC-mismatched mouse model of allogeneic hematopoietic stem cell transplantation (HCT). Our results showed that Sca1(+) MSCs decreased the severity of acute GVHD (aGVHD) and prolonged the survival period of allogeneic HCT recipients. This effect was exerted through lowered T lymphocyte infiltration in target organs and by inhibition of CD80/86 expression on host dendritic cells. Furthermore, the expression of cytotoxic T-lymphocyte antigen-4 (CTLA-4), a negative regulator of T cells, was elevated in the recipient splenocytes. In conclusion, bone-related Sca1(+) MSCs subpopulation suppressed GVHD and could be a novel treatment for acute GVHD.