Systematic comparison of sequencing-based spatial transcriptomic methods.

Recent developments of sequencing-based spatial transcriptomics (sST) have catalyzed important advancements by facilitating transcriptome-scale spatial gene expression measurement. Despite this progress, efforts to comprehensively benchmark different platforms are currently lacking. The extant variability across technologies and datasets poses challenges in formulating standardized evaluation metrics. In this study, we established a collection of reference tissues and regions characterized by well-defined histological architectures, and used them to generate data to compare 11 sST methods. We highlighted molecular diffusion as a variable parameter across different methods and tissues, significantly affecting the effective resolutions. Furthermore, we observed that spatial transcriptomic data demonstrate unique attributes beyond merely adding a spatial axis to single-cell data, including an enhanced ability to capture patterned rare cell states along with specific markers, albeit being influenced by multiple factors including sequencing depth and resolution. Our study assists biologists in sST platform selection, and helps foster a consensus on evaluation standards and establish a framework for future benchmarking efforts that can be used as a gold standard for the development and benchmarking of computational tools for spatial transcriptomic analysis.

The ATF4-RPS19BP1 axis modulates ribosome biogenesis to promote erythropoiesis.

Hematopoietic differentiation is controlled by intrinsic regulators and the extrinsic hematopoietic niche. Activating transcription factor 4 (ATF4) plays a crucial role in the function of fetal and adult hematopoietic stem cell maintenance; however, the precise function of ATF4 in the bone marrow niche and the mechanism by which ATF4 regulates adult hematopoiesis remain largely unknown. Here, we employ four cell-type-specific mouse Cre lines to achieve conditional knockout of Atf4 in Cdh5+ endothelial cells, Prx1+ bone marrow stromal cells, Osx+ osteo-progenitor cells, and Mx1+ hematopoietic cells, and uncover the role of Atf4 in niche cells and hematopoiesis. Intriguingly, depletion of Atf4 in niche cells does not affect hematopoiesis; however, Atf4-deficient hematopoietic cells exhibit erythroid differentiation defects, leading to hypoplastic anemia. Mechanistically, ATF4 mediates direct regulation of Rps19bp1 transcription, which is, in turn, involved in 40S ribosomal subunit assembly to coordinate ribosome biogenesis and promote erythropoiesis. Finally, we demonstrate that under conditions of 5-fluorouracil-induced stress, Atf4 depletion impedes the recovery of hematopoietic lineages, which requires efficient ribosome biogenesis. Taken together, our findings highlight the indispensable role of the ATF4-RPS19BP1 axis in the regulation of erythropoiesis.

Ruxolitinib improves hematopoietic regeneration by restoring mesenchymal stromal cell function in acute graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) is a severe complication of allogeneic hematopoietic stem cell transplantation. Hematopoietic dysfunction accompanied by severe aGVHD, which may be caused by niche impairment, is a long-standing clinical problem. However, how the bone marrow (BM) niche is damaged in aGVHD hosts is poorly defined. To comprehensively address this question, we used a haplo-MHC-matched transplantation aGVHD murine model and performed single-cell RNA-Seq of nonhematopoietic BM cells. Transcriptional analysis showed that BM mesenchymal stromal cells (BMSCs) were severely affected, with a reduction in cell ratio, abnormal metabolism, compromised differentiation potential, and defective hematopoiesis-supportive function, all of which were validated by functional assays. We found that ruxolitinib, a selective JAK1/2 inhibitor, ameliorated aGVHD-related hematopoietic dysfunction through a direct effect on recipient BMSCs, resulting in improved proliferation ability, adipogenesis/osteogenesis potential, mitochondria metabolism capacity, and crosstalk with donor-derived hematopoietic stem/progenitor cells. By inhibiting the JAK2/STAT1 pathway, ruxolitinib maintained long-term improvement of aGVHD BMSC function. Additionally, ruxolitinib pretreatment in vitro primed BMSCs to better support donor-derived hematopoiesis in vivo. These observations in the murine model were validated in patient samples. Overall, our findings suggest that ruxolitinib can directly restore BMSC function via the JAK2/STAT1 pathway and, in turn, improve the hematopoietic dysfunction caused by aGVHD.

WDR82-binding long noncoding RNA lncEry controls mouse erythroid differentiation and maturation.

Hematopoietic differentiation is controlled by both genetic and epigenetic regulators. Long noncoding RNAs (lncRNAs) have been demonstrated to be important for normal hematopoiesis, but their function in erythropoiesis needs to be further explored. We profiled the transcriptomes of 16 murine hematopoietic cell populations by deep RNA sequencing and identified a novel lncRNA, Gm15915, that was highly expressed in erythroid-related progenitors and erythrocytes. For this reason, we named it lncEry. We also identified a novel lncEry isoform, which was the principal transcript that has not been reported before. lncEry depletion impaired erythropoiesis, indicating the important role of the lncRNA in regulating erythroid differentiation and maturation. Mechanistically, we found that lncEry interacted with WD repeat-containing protein 82 (WDR82) to promote the transcription of Klf1 and globin genes and thus control the early and late stages of erythropoiesis, respectively. These findings identified lncEry as an important player in the transcriptional regulation of erythropoiesis.

Comparisons of Different Models on Dynamic Recrystallization of Plate during Asymmetrical Shear Rolling.

Asymmetrical shear rolling with velocity asymmetry and geometry asymmetry is beneficial to enlarge deformation and refine grain size at the center of the thick plate compared to conventional symmetrical rolling. Dynamic recrystallization (DRX) plays a vital role in grain refinement during hot deformation. Finite element models (FEM) coupled with microstructure evolution models and cellular automata models (CA) are established to study the microstructure evolution of plate during asymmetrical shear rolling. The results show that a larger DRX fraction and a smaller average grain size can be obtained at the lower layer of the plate. The DRX fraction at the lower part increases with the ascending speed ratio, while that at upper part decreases. With the increase of the offset distance, the DRX fraction slightly decreases for the whole thickness of the plate. The differences in the DRX fraction and average grain size between the upper and lower surfaces increase with the ascending speed ratio; however, it varies little with the change of the speed ratio. Experiments are conducted and the CA models have a higher accuracy than FEM models as the grain morphology, DRX nuclei, and grain growth are taken into consideration in CA models, which are more similar to the actual DRX process during hot deformation.

The diverse expression of the WT1 gene in patients with acquired bone marrow failure syndromes.

Acquired bone marrow failure syndromes (aBMFS) encompass a wide range of diseases. A study to investigate WT1 expression in BM was conducted in 387 patients with aBMFS in China. The WT1 level in patients with aplastic anemia (AA) was significantly lower than that in patients with paroxysmal nocturnal hemoglobinuria (PNH, p = .023) and myelodysplastic syndrome (MDS, p < .001). In addition, the WT1 level in patients with MDS significantly increased as the disease progressed to an advanced stage. Patients with hypoplastic MDS had a differentiated expression level of WT1 compared with that of NSAA (p < .001). Furthermore, post-treatment patients of AA with partial response (PR) or complete response (CR) status had relatively higher WT1 levels than those with naive AA (p = .017, p = .003, respectively). Thus, the WT1 expression level could be a useful genetic marker for routine clinical work in aBMFS.

CD106 is a novel mediator of bone marrow mesenchymal stem cells via NF-κB in the bone marrow failure of acquired aplastic anemia.

BACKGROUND: Acquired aplastic anemia (AA) is characterized by deficiency or dysfunction of the bone marrow (BM) microenvironment. However, little is known about the impairment of BM-derived mesenchymal stem cells (MSCs) in AA patients. METHODS: We used Illumina HiSeqTM 2000 sequencing, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry (FCM), and Western blotting to test the expression of CD106 gene (vascular cell adhesion molecule 1 (VCAM1)) and CD106 protein of BM-MSCs. Furthermore, we used hematoxylin and eosin (H&E) and histochemical staining analysis, immunofluorescence, and the formation of capillary-like structures to analyze capillary tube-like formation in vitro; we also used the Matrigel plug assay to test in vivo vasculogenesis, and an assay of colony forming units (CFUs) and colony-forming unit-megakaryocyte (CFU-MK) to detect the support function of MSCs in vitro. The in vivo engraftment of CD34+ cells and MSCs in NOD/SCID mice was tested by FACS and survival assay; the expression of NF-κB was tested by NanoPro analysis and immunofluorescence. NF-κB-regulated CD106 gene (VCAM1) was confirmed by tumor necrosis factor alpha (TNF-α)-stimulated and lipopolysaccharide (LPS)-stimulated MSCs, blockade assay, and immunofluorescence. RESULTS: Here, we report that BM-MSCs from AA patients exhibited downregulation of the CD06 gene (VCAM1) and low expression of CD106 in vitro. Further analysis revealed that CD106+ MSCs from both AA patients and healthy controls had increased potential for in vitro capillary tube-like formation and in vivo vasculogenesis compared with CD106- MSCs, and the results were similar when healthy MSCs were compared with AA MSCs. CD106+ MSCs from both AA patients and healthy controls more strongly supported in vitro growth and in vivo engraftment of CD34+ cells in NOD/SCID mice than CD106- MSCs, and similar results were obtained when healthy MSCs and AA MSCs were compared. The expression of NF-κB was decreased in AA MSCs, and NF-κB regulated the CD106 gene (VCAM1) which supported hematopoiesis. CONCLUSIONS: These results revealed the effect of CD106 and NF-κB in BM failure of AA.

Knockdown of IL-8 Provoked Premature Senescence of Placenta-Derived Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have shown promise for use in cell therapy, and due to their tumor tropism can serve as vehicles for delivering therapeutic agents to tumor sites. Because interleukin-8 (IL-8) is known to mediate the protumor effect of MSCs, elimination of IL-8 secretion by MSCs may enhance their safety for use in cancer gene therapy. However, little is known concerning the effect of endogenously secreted IL-8 on MSCs. We performed studies using placenta-derived MSCs (PMSCs) to determine whether knockdown of IL-8 would influence their biological activity. We first verified that IL-8 and its membrane receptor CXCR2, but not CXCR1, were highly expressed in PMSCs. We then employed lentivirus-mediated small hairpin RNA interference to generate stable IL-8-silenced PMSCs, which displayed a variety of characteristic senescent phenotypes. We observed that at day 9 post-transfection, IL-8-silenced PMSCs had become larger and displayed a more flattened appearance when compared with their controls. Moreover, their proliferation, colony forming unit-fibroblast formation, adipogenic and osteogenic differentiation, and immunosuppressive potentials were significantly impaired. Enhanced senescence-associated ß-galactosidase (SA-ß-gal) activity and specific global gene expression profiles confirmed that IL-8 silencing evoked the senescence process in PMSCs. Increased levels of p-Akt and decreased levels of FOXO3a protein expression suggested that reactive oxygen species played a role in the initiation and maintenance of senescence in IL-8-silenced PMSCs. Notably, the majority of CXCR2 ligands were downregulated in presenescent IL-8-silenced PMSCs but upregulated in senescent cells, indicating an antagonistic pleiotropy of the IL-8/CXCR2 signaling pathway in PMSCs. This effect may promote the proliferation of young cells and accelerate senescence of old cells.

Pro-inflammatory effects of the Th1 chemokine CXCL10 in acquired aplastic anaemia.

CXCL10/IFN-γ-induced protein 10 (IP-10) and its corresponding receptor CXCR3 have long been considered to be involved in the pathophysiology of type 1 T (Th1) cell-orientated autoimmune diseases. However, the exact role of CXCL10 in the pathogenesis of aplastic anaemia (AA) has not been thoroughly studied. The aim of our study was to evaluate the plasma level of CXCL10 and its effects on CD4+ T cell differentiation in AA. In our study, we found that an elevated plasma level of CXCL10 was negatively correlated with platelet, absolute neutrophil and reticulocyte counts, while it was positively correlated with the proportion of lymphocytes in white blood cells in AA patients. To confirm the pro-inflammatory effects of CXCL10 in AA, we isolated CD4+ T cells and evaluated the function of CXCL10 in CD4+ T cell differentiation. In vitro stimulation experiments further revealed the pro-inflammatory role of CXCL10 in AA, partially by promoting the secretion of interferon (IFN)-γ and IL-17. In addition, CXCL10 significantly skewed CD4+ T cell differentiation to Th1 cells and T helper 17 (Th17) cells in AA patients, while it inhibited the differentiation of type 2 T (Th2) cells only in controls. The mRNA expression of transcription factors representative of T cell differentiation was detected by RT-PCR. Consistently, our results showed that after CXCL10 treatment, the expression of T-bet and RORγt was significantly enhanced, while the expression of GATA3 was inhibited. In conclusion, our results indicated that CXCL10, a pro-inflammatory chemokine, might be involved in the abnormal immune response in AA.

[Influence of MicroRNA-382 on Biological Properties of Human Umbilical Cord-Derived Mesenchymal Stem Cells].

OBJECTIVE: To investigate the effect of microRNA-382 (miR-382) on the biological properties of human umbilical cord-derived mesenchymal stem cells (hUC-MSC). METHODS: The mimics and inhibitor of miR-382 were transfected into hUC-MSC with lipo2000. Inverted microscopy was used to observe the morphology change of hUC-MSC. The proliferation of hUC-MSC was detected by CCK-8. Oil red O and alizarin red staining were applied to assess the adipogenic and osteogenic differentiation of hUC-MSC. Cetylpyridinium chloride was used to the quantitative analysis of osteogenic differentiation. The expression of Runx2 and some cytokines were detected by RT-PCR. RESULTS: miR-382 did not influence the morphology, proliferation and adipogenic differentiation of hUC-MSC miR-382 inhibited the expression of Runx2, thus could inhibit the osteogenesis of hUC-MSC, being confirmed by alizarin red stain; miR-382 could influence the expression of key cytokines secreted from hUC-MSC, such as IL-6, IDO1, G-CSF, M-CSF, GM-CSF. CONCLUSION: miR-382 decreases the expression of Runx2 and inhibites the osteogenesis of hUC-MSC. In addition, it also affects the expression of some key cytokines secreted from hUC-MSC.

[Human Umbilical Cord-derived Mesenchymal Stem Cells Secrete Interleukin-6 to Influence Differentiation of Leukemic Cells].

OBJECTIVE: To investigate the effect of human umbilical cord-derived mesenchymal stem cells (UC-MSC) on the differentiation of leukemic cells. METHODS: The co-culture system of UC-MSC with acute promyelocytic leukemic cell line NB4 cells was constructed in vitro,and the differentiation status of the leukemic cells was assessed by cell morphology,nitroblue tetrazolium reduction test,and cell surface differentiation marker CD11b. RESULTS: UC-MSC induced the granulocytic differentiation of NB4 cells. When UC-MSC and a small dose of all-trans retinoic acid were applied together,the differentiation-inducing effect was enhanced in an additive manner. Interleukin (IL)-6Ra neutralization attenuated differentiation and exogenous IL-6-induced differentiation of leukemic cells. CONCLUSION: UC-MSC can promotd granulocytic differentiation of acute promyelocytic leukemia cells by way of IL-6 and presented additive effect when combined with a small dose of all-trans retinoic acid.

VCAM-1+ placenta chorionic villi-derived mesenchymal stem cells display potent pro-angiogenic activity.

INTRODUCTION: Mesenchymal stem cells (MSCs) represent a heterogeneous cell population that is promising for regenerative medicine. The present study was designed to assess whether VCAM-1 can be used as a marker of MSC subpopulation with superior angiogenic potential. METHODS: MSCs were isolated from placenta chorionic villi (CV). The VCAM-1(+/-) CV-MSCs population were separated by Flow Cytometry and subjected to a comparative analysis for their angiogenic properties including angiogenic genes expression, vasculo-angiogenic abilities on Matrigel in vitro and in vivo, angiogenic paracrine activities, cytokine array, and therapeutic angiogenesis in vascular ischemic diseases. RESULTS: Angiogenic genes, including HGF, ANG, IL8, IL6, VEGF-A, TGFß, MMP2 and bFGF, were up-regulated in VCAM-1(+)CV-MSCs. Consistently, angiogenic cytokines especially HGF, IL8, angiogenin, angiopoitin-2, µPAR, CXCL1, IL-1ß, IL-1α, CSF2, CSF3, MCP-3, CTACK, and OPG were found to be significantly increased in VCAM-1(+) CV-MSCs. Moreover, VCAM-1(+)CV-MSCs showed remarkable vasculo-angiogenic abilities by angiogenesis analysis with Matrigel in vitro and in vivo and the conditioned medium of VCAM-1(+) CV-MSCs exerted markedly pro-proliferative and pro-migratory effects on endothelial cells compared to VCAM-1(-)CV-MSCs. Finally, transplantation of VCAM-1(+)CV-MSCs into the ischemic hind limb of BALB/c nude mice resulted in a significantly functional improvement in comparison with VCAM-1(-)CV-MSCs transplantation. CONCLUSIONS: VCAM-1(+)CV-MSCs possessed a favorable angiogenic paracrine activity and displayed therapeutic efficacy on hindlimb ischemia. Our results suggested that VCAM-1(+)CV-MSCs may represent an important subpopulation of MSC for efficient therapeutic angiogenesis.

Impaired Autophagy in Adult Bone Marrow CD34+ Cells of Patients with Aplastic Anemia: Possible Pathogenic Significance.

Aplastic anemia (AA) is a bone marrow failure syndrome that is caused largely by profound quantitative and qualitative defects of hematopoietic stem and progenitor cells. However, the mechanisms underlying these defects remain unclear. Under conditions of stress, autophagy acts as a protective mechanism for cells. We therefore postulated that autophagy in CD34+ hematopoietic progenitor cells (HPCs) from AA patients might be impaired and play a role in the pathogenesis of AA. To test this hypothesis, we tested autophagy in CD34+ cells from AA samples and healthy controls and investigated the effect of autophagy on the survival of adult human bone marrow CD34+ cells. We found that the level of autophagy in CD34+ cells from AA patients was significantly lower than in age/sex-matched healthy controls, and lower in cases of severe AA than in those with non-severe AA. Autophagy in CD34+ cells improved upon amelioration of AA but, compared to healthy controls, was still significantly reduced even in AA patients who had achieved a complete, long-term response. We also showed that although the basal autophagy in CD34+ cells was low, the autophagic response of CD34+ cells to "adversity" was rapid. Finally, impaired autophagy resulted in reduced differentiation and proliferation of CD34+ cells and sensitized them to death and apoptosis. Thus, our results confirm that autophagy in CD34+ cells from AA patients is impaired, that autophagy is required for the survival of CD34+ cells, and that impaired autophagy in CD34+ HPCs may play an important role in the pathogenesis of AA.

Decreased expression of vitamin D receptor may contribute to the hyperimmune status of patients with acquired aplastic anemia.

Acquired aplastic anemia (AA) is an immune-mediated bone marrow failure syndrome. 1α,25-Dihydroxyvitamin D3 [1,25(OH)2 D3 ], the biologically active metabolite of vitamin D, is a critical modulator of immune response via binding with vitamin D receptor (VDR). Previous studies have established that 1,25(OH)2 D3 and VDR were involved in the pathogenesis of some autoimmune diseases. In this study, we evaluated the involvement of 1,25(OH)2 D3 and VDR on T-cell responses in AA. Plasma 25(OH)D3 levels were comparable between patients with AA and healthy controls. Surprisingly, VDR mRNA was significantly lower in untreated patients with AA than in healthy controls. Subsequent in vitro experiments revealed that 1,25(OH)2 D3 treatment suppressed the proliferation of lymphocytes and inhibited the secretion of interferon-γ, tumor necrosis factor-α, and interleukin-17A, meanwhile promoting the production of transforming growth factor-ß1 in patients with AA. Moreover, 1,25(OH)2 D3 inhibited the differentiation of type 1 and Th17 cells but induced the differentiation of type 2 and regulatory T cells. Interestingly, VDR mRNA was elevated in healthy controls after 1,25(OH)2 D3 treatment, but not in patients with AA. In conclusion, decreased expression of VDR might contribute to the hyperimmune status of AA and appropriate vitamin D supplementation could partly correct the immune dysfunction by strengthening signal transduction through VDR in patients with AA.

Anti-inflammatory effects of interleukin-35 in acquired aplastic anemia.

Interleukin (IL)-35 is a novel regulatory cytokine primarily produced by regulatory T cells. Accumulating evidence has established that IL-35 plays an important role in the regulation of immune homeostasis, but little is known regarding the function of IL-35 in acquired aplastic anemia (AA). The aim of the present study was to investigate the expression of IL-35 and its effects on T cell response in AA. Our study demonstrated that significantly decreased plasma levels of IL-35 in AA were closely correlated with disease severity. In vitro stimulation experiment further confirmed the anti-inflammatory effects of IL-35, including suppressing the proliferation of CD4(+) and CD8(+) effector T cells, inhibiting the secretion of interferon-γ, tumor necrosis factor-α and IL-17 and promoting the production of transforming growth factor-ß by peripheral blood mononuclear cells from patients with AA. Furthermore, we established that IL-35 inhibited the differentiation of type 1 T cells and T helper 17 cells but promoted the differentiation of type 2 T cells. Accordingly, the expression of T-bet and RORγt was inhibited while the expression of GATA3 was induced after IL-35 treatment. In summary, our findings suggested that decreased IL-35 might contribute to the loss of immune-tolerance and be critically involved in the pathogenesis of AA.

Inhibition of Notch Signaling Promotes the Adipogenic Differentiation of Mesenchymal Stem Cells Through Autophagy Activation and PTEN-PI3K/AKT/mTOR Pathway.

BACKGROUND: The Notch signaling pathway is implicated in a broad range of developmental processes, including cell fate decisions. This study was designed to determine the role of Notch signaling in adipogenic differentiation of human bone marrow derived MSCs (BM-MSCs). METHODS: The Notch signaling was inhibited by the γ-secretase inhibitor N-[N-(3,5-difluor- ophenacetyl-L-alanyl)]-S-phenylglycine t-butylester (DAPT). The markers involving adipogenic differentiation of MSCs, the relative pathway PTEN-PI3K/Akt/mTOR and autophagy activation were then analyzed. Furthermore, the autophagy inhibitor chloroquine (CQ) and 3-methyladenine (3-MA) were used to study the role of autophagy in the DAPT-induced the adipogenic differentiation of MSCs. RESULTS: We first confirmed the down -regulation of Notch gene expression during MSCs adipocyte differentiation, and showed that the inhibition of Notch signaling significantly enhanced adipogenic differentiation of MSCs. Furthermore, Notch inhibitor DAPT induced early autophagy by acting on PTEN-PI3K/Akt/mTOR pathway. The autophagy inhibitor CQ and 3-MA dramatically abolished the effects of DAPT-induced autophagy and adipogenic differentiation of MSCs. CONCLUSION: Our results indicate that inhibition of Notch signaling could promote MSCs adipogenesis mediated by autophagy involving PTEN-PI3K/Akt/mTOR pathway. Notch signaling could be a novel target for regulating the adipogenic differentiation of MSCs.

Aberrant expression and significance of OCT-4A transcription factor in leukemia cells.

OBJECTIVE: To determine the contribution of the OCT-4 to the pathogenesis of leukemia. METHODS: Bone marrow (BM) samples obtained from 72 patients with leukemia, and 18 normal healthy subjects were assayed for their OCT-4 expression using both flow cytometry and RT-PCR. RESULTS: OCT-4 expression in BM nucleated cells of acute leukemia patients (n=33) was significantly higher than that of complete remission and chronic phase leukemia patients (n=39, p<0.001) and healthy donors (n=18, p<0.001). OCT-4 expression had a significant positive relation with CD34 expression (n=43, r=0.721, p<0.001) and the proportion of naive cells (n=60, r=0.687, p<0.001). In addition, the results of QRT-PCR detection showed that the OCT-4A had increased expression in BM nucleated cells in the patients with acute leukemia (n=33, median 16.585, range 0.38-169.62) compared to that in leukemia patients with chronic phase and in complete remission (n=39, median 3.34, range 0.04-44.49, p<0.001) and that of normal controls (n=18, median 2.89, range 0.18-16.23, p<0.001). CONCLUSION: OCT-4A expression was significantly increased in the BM nucleated cells of patients with acute leukemia, indicating that OCT-4A may play an important role in the pathogenesis of leukemia and may serve as a molecular target for the development of novel diagnostic and treatment strategies in leukemia.

[Biological characteristics of exosomes secreted by human bone marrow mesenchymal stem cells].

This study was aimed to explore the immunoregulatory function and capability supporting the angiogenesis of exosomes secreted by bone marrow mesenchymal stem cells (BMMSC) from healthy persons. Supernatant of BMMSC (P4-P6) was collected for exosome purification. Transmission electron microscopy (TEM) and Western blot were used to identify the quality of isolated exosomes. The amount of exosomes was quantified through bicinchoninic acid (BCA) protein assay. Human peripheral blood mononuclear cells (PBMNC) were isolated from healthy donor and added with isolating exosomes. After co-cultured for 72 h, IFN-γ from the co-culture system was detected by ELISA. The expression of miRNA-associated with immunity were detected by real-time reverse transcription polymerase chain reaction (Real-time RT-PCR). The interactions between exosomes and human umbilical vein endothelial cells (HUVEC) were observed with confocal microscopy. Subconfluent HUVEC were harvested and treated with the indicated concentration of exosomes. Nude mice were injected subcutaneously with exosomes or PBS as control to verify the ability of angiogenesis. The results showed that diameter range of exosomes was range from 40 to 160 nm. The isolated exosomes expressed the CD9. There was approximately linear relation between the secretion of exosomes and cell density. The exosomes suppressed the production of IFN-γ from PBMNC, and contained miRNA associated with immune regulation such as miR301, miR22 and miR-let-7a. Exosomes induced vascular tube formation in vitro and vascularization of Matrigel plugs in vivo. It is concluded that the BMMSC-derived exosomes can regulate immunity and support vascularization.

[Effects of rapamycin on biological characteristics of bone marrow mesenchymal stem cells from patients with aplastic anemia].

This study was aimed to investigate the effects of rapamycin on biological function and autophagy of bone marrow mesenchymal stem cells (BM-MSC) from patients with aplastic anemia so as to provide experimental basis for the clinical treatment of aplastic anemia (AA) with rapamycin. BM-MSC were treated with different concentrations of rapamycin (0, 10, 50, 100 nmol/L) for 48 h, the expression of LC3B protein was detected by Western blot to observe the effect of rapamycin on cell autophagy; cell apoptosis and cell cycles were detected by flow cytometry; the proliferation of BM-MSC of AA patients was measured by cell counting kit-8; the adipogenic differentiation of BM-MSC were tested by oil red O staining after adipogenic induction for 2 weeks; the adipogenic related genes (LPL, CFD, PPARγ) were detected by real-time PCR. The results showed that the proliferation and adipogenesis of BM-MSC of AA patients were inhibited by rapamycin. Moreover, the autophagy and apoptosis of BM-MSC were increased by rapamycin in a dose-dependent way.Rapamycin arrested the BM-MSC in G0/G1 phase and prevented them into S phase (P < 0.05). It is concluded that rapamycin plays an critical role in inhibiting cell proliferation, cell cycles, and adipogenesis, these effects may be related with the autophagy activation and mTOR inhibition resulting from rapamycin.