Browsing by Subject "Bone Marrow Cells"
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Item Open Access An immunoglobulin C kappa-reactive single chain antibody fusion protein induces tolerance through receptor editing in a normal polyclonal immune system.(J Exp Med, 2005-03-07) Ait-Azzouzene, Djemel; Verkoczy, Laurent; Peters, Jorieke; Gavin, Amanda; Skog, Patrick; Vela, José Luis; Nemazee, DavidUnderstanding immune tolerance mechanisms is a major goal of immunology research, but mechanistic studies have generally required the use of mouse models carrying untargeted or targeted antigen receptor transgenes, which distort lymphocyte development and therefore preclude analysis of a truly normal immune system. Here we demonstrate an advance in in vivo analysis of immune tolerance that overcomes these shortcomings. We show that custom superantigens generated by single chain antibody technology permit the study of tolerance in a normal, polyclonal immune system. In the present study we generated a membrane-tethered anti-Igkappa-reactive single chain antibody chimeric gene and expressed it as a transgene in mice. B cell tolerance was directly characterized in the transgenic mice and in radiation bone marrow chimeras in which ligand-bearing mice served as recipients of nontransgenic cells. We find that the ubiquitously expressed, Igkappa-reactive ligand induces efficient B cell tolerance primarily or exclusively by receptor editing. We also demonstrate the unique advantages of our model in the genetic and cellular analysis of immune tolerance.Item Open Access Bone Marrow Mesenchymal Stem Cell Transplantation Increases GAP-43 Expression via ERK1/2 and PI3K/Akt Pathways in Intracerebral Hemorrhage.(Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology, 2017-01) Cui, Jianzhong; Cui, Changmeng; Cui, Ying; Li, Ran; Sheng, Huaxin; Jiang, Xiaohua; Tian, Yanxia; Wang, Kaijie; Gao, JunlingBackground/aims
Intracerebral hemorrhage (ICH) occurs in hypertensive patients and results in high rates of mortality and disability. This study determined whether bone marrow mesenchymal stem cell (BMSC) transplantation affects axonal regeneration and examined the underlying mechanisms after the administration of PD98059 (p-ERK1/2 inhibitor) or/ and LY294002 (PI3K inhibitor). The hypothesis that was intended to be tested was that BMSC transplantation regulates the expression of growth-associated protein-43 (GAP-43) via the ERK1/2 and PI3K/Akt signaling pathways.Methods
Seventy-five male rats (250-280 g) were subjected to intracerebral blood injection and then randomly received a vehicle, BMSCs, PD98059 or LY294002 treatment. Neurological deficits were evaluated prior to injury and at 1, 3 and 7 days post-injury. The expression of GAP-43, Akt, p-Akt, ERK1/2, and p-ERK1/2 proteins was measured by western blot analysis.Results
BMSC transplantation attenuated neurological deficits 3-7 days post-ICH. The expression of GAP-43 was increased 3 days following BMSC transplantation. However, this increase was inhibited by either PD98059 or LY294002 treatment. Treatment with both PD98059 and LY294002 was more effective than was treatment with an individual compound.Conclusion
BMSC transplantation could attenuate neurological deficits and activate axonal regeneration in this rat ICH model. The protective effects might be associated with increased GAP-43 expression by activating both the ERK1/2 and PI3K/Akt signaling pathways.Item Open Access Chondrogenesis of adult stem cells from adipose tissue and bone marrow: induction by growth factors and cartilage-derived matrix.(Tissue Eng Part A, 2010-02) Diekman, Brian O; Rowland, Christopher R; Lennon, Donald P; Caplan, Arnold I; Guilak, FarshidOBJECTIVES: Adipose-derived stem cells (ASCs) and bone marrow-derived mesenchymal stem cells (MSCs) are multipotent adult stem cells with potential for use in cartilage tissue engineering. We hypothesized that these cells show distinct responses to different chondrogenic culture conditions and extracellular matrices, illustrating important differences between cell types. METHODS: Human ASCs and MSCs were chondrogenically differentiated in alginate beads or a novel scaffold of reconstituted native cartilage-derived matrix with a range of growth factors, including dexamethasone, transforming growth factor beta3, and bone morphogenetic protein 6. Constructs were analyzed for gene expression and matrix synthesis. RESULTS: Chondrogenic growth factors induced a chondrocytic phenotype in both ASCs and MSCs in alginate beads or cartilage-derived matrix. MSCs demonstrated enhanced type II collagen gene expression and matrix synthesis as well as a greater propensity for the hypertrophic chondrocyte phenotype. ASCs had higher upregulation of aggrecan gene expression in response to bone morphogenetic protein 6 (857-fold), while MSCs responded more favorably to transforming growth factor beta3 (573-fold increase). CONCLUSIONS: ASCs and MSCs are distinct cell types as illustrated by their unique responses to growth factor-based chondrogenic induction. This chondrogenic induction is affected by the composition of the scaffold and the presence of serum.Item Open Access Colonizing the heart from the epicardial side.(Stem Cell Res Ther, 2012-04-30) Bursac, NenadThe clinical use of stem cells, such as bone marrow-derived and, more recently, resident cardiac stem cells, offers great promise for treatment of myocardial infarction and heart failure. The epicardium-derived cells have also attracted attention for their angiogenic paracrine actions and ability to differentiate into cardiomyocytes and vascular cells when activated during cardiac injury. In a recent study, Chong and colleagues have described a distinct population of epicardium-derived mesenchymal stem cells that reside in a perivascular niche of the heart and have a broad multilineage potential. Exploring the therapeutic capacity of these cells will be an exciting future endeavor.Item Open Access Epidermal growth factor regulates hematopoietic regeneration after radiation injury.(Nat Med, 2013-03) Doan, Phuong L; Himburg, Heather A; Helms, Katherine; Russell, J Lauren; Fixsen, Emma; Quarmyne, Mamle; Harris, Jeffrey R; Deoliviera, Divino; Sullivan, Julie M; Chao, Nelson J; Kirsch, David G; Chute, John PThe mechanisms that regulate hematopoietic stem cell (HSC) regeneration after myelosuppressive injury are not well understood. We identified epidermal growth factor (EGF) to be highly enriched in the bone marrow serum of mice bearing deletion of Bak and Bax in TIE2-expressing cells in Tie2Cre; Bak1(-/-); Bax(flox/-) mice. These mice showed radioprotection of the HSC pool and 100% survival after a lethal dose of total-body irradiation (TBI). Bone marrow HSCs from wild-type mice expressed functional EGF receptor (EGFR), and systemic administration of EGF promoted the recovery of the HSC pool in vivo and improved the survival of mice after TBI. Conversely, administration of erlotinib, an EGFR antagonist, decreased both HSC regeneration and the survival of mice after TBI. Mice with EGFR deficiency in VAV-expressing hematopoietic cells also had delayed recovery of bone marrow stem and progenitor cells after TBI. Mechanistically, EGF reduced radiation-induced apoptosis of HSCs and mediated this effect through repression of the proapoptotic protein PUMA. Our findings show that EGFR signaling regulates HSC regeneration after myelosuppressive injury.Item Open Access Ex vivo expansion of murine and human hematopoietic stem cells.(Methods Mol Biol, 2014) Doan, Phuong L; Chute, John PHematopoietic stem cells have the capacity to self-renew and give rise to the entirety of the mature blood and immune system throughout the lifespan of an organism. Here, we describe methods to isolate and culture murine bone marrow (BM) CD34(-)ckit(+)Sca1(+)Lineage(-) (CD34(-)KSL) hematopoietic stem cells (HSCs). We also describe a method to measure functional HSC content via the competitive repopulation assay. Furthermore, we summarize methods to isolate and culture human CD34(+)CD38(-)Lineage(-) cells which are enriched for human hematopoietic stem and progenitor cells.Item Open Access In situ studies of the primary immune response to (4-hydroxy-3-nitrophenyl)acetyl. V. Affinity maturation develops in two stages of clonal selection.(J Exp Med, 1998-03-16) Takahashi, Y; Dutta, PR; Cerasoli, DM; Kelsoe, GTo examine the role of germinal centers (GCs) in the generation and selection of high affinity antibody-forming cells (AFCs), we have analyzed the average affinity of (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific AFCs and serum antibodies both during and after the GC phase of the immune response. In addition, the genetics of NP-binding AFCs were followed to monitor the generation and selection of high affinity AFCs at the clonal level. NP-binding AFCs gradually accumulate in bone marrow (BM) after immunization and BM becomes the predominant locale of specific AFCs in the late primary response. Although the average affinity of NP-specific BM AFCs rapidly increased while GCs were present (GC phase), the affinity of both BM AFCs and serum antibodies continued to increase even after GCs waned (post-GC phase). Affinity maturation in the post-GC phase was also reflected in a shift in the distribution of somatic mutations as well as in the CDR3 sequences of BM AFC antibody heavy chain genes. Disruption of GCs by injection of antibody specific for CD154 (CD40 ligand) decreased the average affinity of subsequent BM AFCs, suggesting that GCs generate the precursors of high affinity BM AFCs; inhibition of CD154-dependent cellular interactions after the GC reaction was complete had no effect on high affinity BM AFCs. Interestingly, limited affinity maturation in the BM AFC compartment still occurs during the late primary response even after treatment with anti-CD154 antibody. Thus, GCs are necessary for the generation of high affinity AFC precursors but are not the only sites for the affinity-driven clonal selection responsible for the maturation of humoral immune responses.Item Open Access Inflammation controls B lymphopoiesis by regulating chemokine CXCL12 expression.(J Exp Med, 2004-01-05) Ueda, Yoshihiro; Yang, Kaiyong; Foster, Sandra J; Kondo, Motonari; Kelsoe, GarnettInflammation removes developing and mature lymphocytes from the bone marrow (BM) and induces the appearance of developing B cells in the spleen. BM granulocyte numbers increase after lymphocyte reductions to support a reactive granulocytosis. Here, we demonstrate that inflammation, acting primarily through tumor necrosis factor alpha (TNFalpha), mobilizes BM lymphocytes. Mobilization reflects a reduced CXCL12 message and protein in BM and changes to the BM environment that prevents homing by cells from naive donors. The effects of TNFalpha are potentiated by interleukin 1 beta (IL-1beta), which acts primarily to expand the BM granulocyte compartment. Our observations indicate that inflammation induces lymphocyte mobilization by suppressing CXCL12 retention signals in BM, which, in turn, increases the ability of IL-1beta to expand the BM granulocyte compartment. Consistent with this idea, lymphocyte mobilization and a modest expansion of BM granulocyte numbers follow injections of pertussis toxin. We propose that TNFalpha and IL-1beta transiently specialize the BM to support acute granulocytic responses and consequently promote extramedullary lymphopoiesis.Item Open Access Relaxed negative selection in germinal centers and impaired affinity maturation in bcl-xL transgenic mice.(J Exp Med, 1999-08-02) Takahashi, Y; Cerasoli, DM; Dal Porto, JM; Shimoda, M; Freund, R; Fang, W; Telander, DG; Malvey, EN; Mueller, DL; Behrens, TW; Kelsoe, GThe role of apoptosis in affinity maturation was investigated by determining the affinity of (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific antibody-forming cells (AFCs) and serum antibody in transgenic mice that overexpress a suppressor of apoptosis, Bcl-xL, in the B cell compartment. Although transgenic animals briefly expressed higher numbers of splenic AFCs after immunization, the bcl-xL transgene did not increase the number or size of germinal centers (GCs), alter the levels of serum antibody, or change the frequency of NP-specific, long-lived AFCs. Nonetheless, the bcl-xL transgene product, in addition to endogenous Bcl-xL, reduced apoptosis in GC B cells and resulted in the expansion of B lymphocytes bearing VDJ rearrangements that are usually rare in primary anti-NP responses. Long-lived AFCs bearing these noncanonical rearrangements were frequent in the bone marrow and secreted immunoglobulin G(1) antibodies with low affinity for NP. The abundance of noncanonical cells lowered the average affinity of long-lived AFCs and serum antibody, demonstrating that Bcl-xL and apoptosis influence clonal selection/maintenance for affinity maturation.