Stromal Derived Factor-1 Expression Research Articles

Hypoxia as a stimulus for tissue formation: The concept of organogenesis in microsurgically vascularized tissue engineering constructs

Axial vascularization of tissue constructs is essential to maintain an adequate blood supply for a stable regeneration of a clinically relevant tissue size. The versatility of the arterio-venous loop (AVL) has been previously shown in various small and large animal models as well as in clinical reports for bone regeneration. We have previously demonstrated the capability of the AVL to induce axial vascularization and to support the nourishment of tissue constructs in small animal models after applying high doses of ionizing radiation comparable to those applied for adjuvant radiotherapy after head and neck cancer. We hypothesize that this robust ability to induce regeneration after irradiation could be related to a state of hypoxia inside the constructs that triggers the HIF1 (hypoxia induced factor 1) - SDF1 (stromal derived factor 1) axis leading to chemotaxis of progenitor cells and induction of tissue regeneration and vascularization. We analyzed the expression of HIF1 and SDF1 via immunofluorescence in axially vascularized bone tissue engineering constructs in Lewis rats 2 and 5 weeks after local irradiation with 9Gy or 15Gy. We also analyzed the expression of various genes for osteogenic differentiation (collagen 1, RUNX, alkaline phosphatase and osteonectin) via real time PCR analysis. The expression of HIF1 and SDF1 was enhanced two weeks after irradiation with 15Gy in comparison to non-irradiated constructs. The expression of osteogenic markers was enhanced at the 5-weeks time point with significant results regarding collagen, alkaline phosphatase and osteonectin. These results indicate that the hypoxia within the AVL constructs together with an enhanced SDF1 expression probably play a role in promoting tissue differentiation. The process of tissue generation triggered by hypoxia in the vicinity of a definite vascular axis with enhanced tissue differentiation over time resembles hereby the well-known concept of organogenesis in fetal life.

Soybean Elicited with Saccharomyces cerevisiae and Light Attenuates Stromal-Derived Factor-1 Associated with CXCR4 in High-Fat/Fructose Diet Mice

Abstract Soybean elicited with microorganisms transforms its phytochemical content which is rich in anti-inflammatory action. However, the potential effect of the elicited soybean extract (ESE) on the maintenance of the stromal-derived factor-1 (SDF-1) regulatory system in the spleen, thymus, hepar, and bone marrow in high-fat/fructose diet (HFFD) mice is yet to be investigated. In our study, the spleen, thymus, hepar, and femurs were collected and isolated at the end of the experiment. The expression of SDF-1 in hepar, CD4+, CD8+, T cells, and B220+ cells was measured using flow cytometry analysis. To determine the interaction between the active compound of ESE and CXCR4, docking analysis was conducted using PyRx 0.8. The expression of splenic and thymic CD4+SDF-1+, CD8+SDF-1+, and hepatic SDF-1+ was elevated in HFFD mice but not in normal diet (ND) mice. ESE had significantly declined (P < 0.05) in CD4+SDF-1+ and CD8+SDF-1+ T-cells subsets. ESE treatment improved the development of B cells in HFFD mice. The molecular docking analysis identified glyceollin I with the strongest affinity of −8.4 kcal/mol. The results suggest that glyceollin I has a positive effect as a CXCR4 inhibitor. ESE supplementation was significant in maintaining the regulatory system of SDF-1 expressed by CD4+, CD8+, hepatocyte, and B220+ cells in HFFD associated with obesity Keywords: CXCR4, Glyceollin, High-fat, High-fructose, SDF-1, Soybean

DNA methylation is involved in the microRNA-886-3p gene expression and plays a potential role in hematopoietic stem and progenitor cell mobilization through affecting SDF-1

The role of the sympathetic nervous system (SNS) in hematopoietic stem and progenitor cell (HSPC) mobilization has been largely investigated. However, there is a critical need for the identification of the underlying contributing factors to improve HSPC yield for transplantation. It has been demonstrated that miR-886-3p targets stromal-derived factor-1 (SDF-1), the central mediator of mobilization, and therefore may play a part in this process. Besides, miR-886-3p expression can be epigenetically regulated through DNA methylation modifications inits gene promoter. Here, to assess the contribution of miR-886-3p and other epigenetic factors in HSPC mobilization, human bone marrow-derived mesenchymal stem cells (MSCs) were treated with the β-adrenergic agonist of isoprenaline. The expression of miR-886-3p and SDF-1and the gene promoter methylation status of this miRNA were then respectively evaluated through the appropriate PCR techniques. As expected, despite a transient initial increase in SDF-1mRNA level, its expression reduced, and miR-886-3plevel remarkably increased 48 h following treatment. The gene promoter methylation pattern of miR-886-3p also changed from a full methylated state to a partially methylated one. Together, our findings suggest that miR-886-3p can be epigenetically regulated and through suppressing the expression of SDF-1 play an active role in the SNS-mediated HSPC mobilization.

The P2X4 purinergic receptor has emerged as a potent regulator of hematopoietic stem/progenitor cell mobilization and homing-a novel view of P2X4 and P2X7 receptor interaction in orchestrating stem cell trafficking.

Recent evidence indicates that extracellular adenosine triphosphate (eATP), as a major mediator of purinergic signaling, plays an important role in regulating the mobilization and homing of hematopoietic stem progenitor cells (HSPCs). In our previous work we demonstrated that eATP activates the P2X7 ion channel receptor in HSPCs and that its deficiency impairs stem cell trafficking. To learn more about the role of the P2X purinergic receptor family in hematopoiesis, we phenotyped murine and human HSPCs with respect to the seven P2X receptors and observed that, these cells also highly express P2X4 receptors, which shows ~50% sequence similarity to P2X7 subtypes, but that P2X4 cells are more sensitive to eATP and signal much more rapidly. Using the selective P2X4 receptor antagonist PSB12054 as well as P2X4-KO mice, we found that the P2X4 receptor, similar to P2X7 receptor, promotes trafficking of HSPCs in that its deficiency leads to impaired chemotaxis of HSPCs in response to a stromal-derived factor 1 (SDF-1) gradient, less effective pharmacological mobilization, and defective homing and engraftment of HSPCs after transplantation into myeloablated hosts. This correlated with a decrease in SDF-1 expression in the BM microenvironment. Overall, our results confirm the proposed cooperative dependence of both receptors in response to eATP signaling. In G-CSF-induced mobilization, a lack of one receptor is not compensated by the presence of the other one, which supports their mutual dependence in regulating HSPC trafficking.

Curcumin promotes the proliferation, invasion of neural stem cells and formation of neurospheres via activating SDF-1/CXCR4 axis.

Curcumin is an active ingredient isolated from the rhizomes of Curcuma longa Linn with remarkably non-toxic bioavailability. This is an in vitro study. In this study, we explored the effects of curcumin on the proliferation, migration and neurogenesis of neural stem cells (NSCs). Primary NSCs were isolated from embryonic day 14 rats and then treated with curcumin and/or stromal derived factor-1 (SDF-1). NSCs showed an SDF-1-dependent proliferation and migration. Further results showed that curcumin and SDF-1 both promoted NSCs proliferation, migration and the formation of neurospheres. In addition, Curcumin up-regulated the expression of SDF-1 and promoted the formation of SDF-1/CXCR4 complex in NSCs. The western blot results showed that the phosphorylation levels of ERK, JNK, MAPK, NF-kB and Akt were up-regulated by curcumin. In contrast, the administration of CXCR4 inhibitor AMD3100 could offset the effect of curcumin. These results suggested that curcumin promoted the NSCs proliferation, migration and formation of neurospheres via SDF-1/CXCR4 in NSCs.

Nlrp3 Inflammasome Signaling Regulates the Homing and Engraftment of Hematopoietic Stem Cells (HSPCs) by Enhancing Incorporation of CXCR4 Receptor\xa0into Membrane Lipid Rafts

Fast and efficient homing and engraftment of hematopoietic stem progenitor cells (HSPCs) is crucial for positive clinical outcomes from transplantation. We found that this process depends on activation of the Nlrp3 inflammasome, both in the HSPCs to be transplanted and in the cells in the recipient bone marrow (BM) microenvironment. For the first time we provide evidence that functional deficiency in the Nlrp3 inflammasome in transplanted cells or in the host microenvironment leads to defective homing and engraftment. At the molecular level, functional deficiency of the Nlrp3 inflammasome in HSPCs leads to their defective migration in response to the major BM homing chemoattractant stromal-derived factor 1 (SDF-1) and to other supportive chemoattractants, including sphingosine-1-phosphate (S1P) and extracellular adenosine triphosphate (eATP). We report that activation of the Nlrp3 inflammasome increases autocrine release of eATP, which promotes incorporation of the CXCR4 receptor into membrane lipid rafts at the leading surface of migrating cells. On the other hand, a lack of Nlrp3 inflammasome expression in BM conditioned for transplantation leads to a decrease in expression of SDF-1 and danger-associated molecular pattern molecules (DAMPs), which are responsible for activation of the complement cascade (ComC), which in turn facilitates the homing and engraftment of HSPCs.

Xenofree generation of limbal stem cells for ocular surface advanced cell therapy

BackgroundLimbal stem cells (LSC) sustain the corneal integrity and homeostasis. LSC deficiency (LSCD) leads to loss of corneal transparency and blindness. A clinical approach to treat unilateral LSCD comprises autologous cultured limbal epithelial stem cell transplantation (CLET). CLET uses xenobiotic culture systems with potential zoonotic transmission risks, and regulatory guidelines make necessary to find xenofree alternatives.MethodsWe compared two xenofree clinical grade media and two feeder layers. We used CnT07, a defined commercial medium for keratinocytes, and a modified xenofree supplemented hormonal epithelial medium with human serum (XSHEM). Optimal formulation was used to compare two feeder layers: the gold standard 3T3 murine fibroblasts and human processed lipoaspirate cells (PLA). We tested the expressions of ΔNp63α and cytokeratin 3 and 12 by qPCR and immunofluorescence. Morphology, viability, clonogenicity, proliferation, and cell growth assays were carried out. We also evaluated interleukin 6 (IL-6) and stromal-derived factor 1 (SDF-1) by qPCR and ELISA.ResultsXSHEM maintained better LSC culture viability and morphology than CnT07. Irradiated PLA feeder cells improved the undifferentiated state of LSC and enhanced their growth and clonogenicity stimulating IL-6 secretion and SDF-1 expression, as well as increased proliferation and cell growth when compared with irradiated 3T3 feeder cells.ConclusionsThe combination of XSHEM and PLA feeder cells efficiently sustained LSC xenofree cultures for clinical application. Moreover, PLA feeder layers were able to improve the LSC potential characteristics. Our results would have direct clinical application in CLET for advanced therapy.Graphical abstract

Intra-tracheal administration of a naked plasmid expressing stromal derived factor-1 improves lung structure in rodents with experimental bronchopulmonary dysplasia

BackgroundBronchopulmonary dysplasia (BPD) is characterized by alveolar simplification and disordered angiogenesis. Stromal derived factor-1 (SDF-1) is a chemokine which modulates cell migration, proliferation, and angiogenesis. Here we tested the hypothesis that intra-tracheal (IT) administration of a naked plasmid DNA expressing SDF-1 would attenuate neonatal hyperoxia-induced lung injury in an experimental model of BPD, by promoting angiogenesis.Design/methodsNewborn Sprague-Dawley rat pups (n = 18–20/group) exposed to room air (RA) or hyperoxia (85% O2) from postnatal day (P) 1 to 14 were randomly assigned to receive IT a naked plasmid expressing SDF-1, JVS-100 (Juventas Therapeutics, Cleveland, Ohio) or placebo (PL) on P3. Lung alveolarization, angiogenesis, inflammation, vascular remodeling and pulmonary hypertension (PH) were assessed on P14. PH was determined by measuring right ventricular systolic pressure (RVSP) and the weight ratio of the right to left ventricle + septum (RV/LV + S). Capillary tube formation in SDF-1 treated hyperoxia-exposed human pulmonary microvascular endothelial cells (HPMEC) was determined by matrigel assay. Data is expressed as mean ± SD and analyzed by two-way ANOVA.ResultsExposure of neonatal pups to 14 days of hyperoxia decreased lung SDF-1 gene expression. Moreover, whilst hyperoxia exposure inhibited capillary tube formation in HPMEC, SDF-1 treatment increased tube length and branching in HPMEC. PL-treated hyperoxia-exposed pups had decreased alveolarization and lung vascular density. This was accompanied by an increase in RVSP, RV/LV + S, pulmonary vascular remodeling and inflammation. In contrast, IT JVS-100 improved lung structure, reduced inflammation, PH and vascular remodeling.ConclusionsIntratracheal administration of a naked plasmid expressing SDF-1 improves alveolar and vascular structure in an experimental model of BPD. These findings suggest that therapies which modulate lung SDF-1 expression may have beneficial effects in preterm infants with BPD.

Oncostatin M Mediates Adipocyte Expression and Secretion of Stromal-Derived Factor 1.

Adipose tissue homeostasis depends on interactions between stromal cells, adipocytes, and the cytokines and chemokines they produce. The gp130 cytokine, oncostatin M (OSM), plays a role in adipose tissue homeostasis. Mice, lacking the OSM receptor (OSMR) in adipocytes (OsmrFKO mice), exhibit derangements in adipose tissue, insulin sensitivity, and immune cell balance. Here, we describe a possible role for the chemokine stromal-derived factor 1 (SDF-1) in these alterations. We treated 3T3-L1 adipocytes with OSM and observed a suppression of SDF-1 gene expression and protein secretion, an effect which was partially blunted by OSMR knockdown. However, OsmrFKO mice also exhibited decreased SDF-1 gene and protein expression in adipose tissue. These contrasting results suggest that the loss of adipocyte OSM–OSMR signaling in vivo may be indirectly affecting adipokine production and secretion by altering OSM target genes to ultimately decrease SDF-1 expression in the OsmrFKO mouse. We conclude that adipocyte OSM–OSMR signaling plays a role in adipose tissue SDF-1 production and may mitigate its effects on adipose tissue homeostasis.

17β-estradiol promotes recovery after myocardial infarction by enhancing homing and angiogenic capacity of bone marrow-derived endothelial progenitor cells through ERα-SDF-1/CXCR4 crosstalking.

17β-estradiol (E2) has been shown to mediate endothelial progenitor cells (EPCs) to repair infarcted myocardium. Both estrogen receptor α (ERα) and stromal derived factor-1 (SDF-1)/CXCR4 signaling pathways may play a critical role in regulating homing and angiogenesis of EPCs in this process. However, the interaction between ERα and SDF-1/CXCR4 signaling pathways remains unclear. In response to E2, the expression of SDF-1 and CXCR4 in EPCs from ovariectomized BALB/C mice was obviously up-regulated, in addition, the migration and tube formation of EPCs in vitro were also significantly enhanced. However, ERα antagonist (MMP) and CXCR4 inhibitor (AMD3100) significantly decreased the migration and tube length of EPCs, even if mediated by E2. The combined treatment of MMP and AMD3100 exerted more inhibitory effects on migration and tube formation of EPCs induced by E2. In in vivo studies, ovariectomized mice were induced acute myocardial infarction (AMI), and divided into four groups (n = 6): non-preconditioned EPCs (3 × 106) group, E2-preconditioned EPCs group, MMP + AMD3100 preconditioned EPCs group, and EPCs pretreated with E2 + MMP + AMD3100 group. E2 group displayed a greater number of homing EPCs, increased capillary density in infarcted myocardium, decreased left ventricular (LV) fibrosis. Nevertheless, these effects of E2 were almost completely blocked by the combined treatment of MMP and AMD3100. E2 can produce cardiovascular protective effects in AMI setting by enhancing homing and angiogenic capacity of EPCs through ERα and CXCR4 signaling pathways, which means that ERα and CXCR4 pathways are effective targets for the development of treatment strategies for AMI.

The homing of bone marrow stem cells is differentially activated in ischemic and valvular heart\xa0diseases and influenced by beta-blockers

BackgroundCell homing is the mechanism by which an injury releases signaling molecules that cause recruitment, proliferation, migration and differentiation of progenitor cells. Stromal derived factor-1 (SDF-1) and its receptor CXCR4 are key molecules involved in homing and little is known about their activation in cardiopathies. Here, we assessed the homing activation status of bone marrow cells (BMC) concerning the SDF-1 and CXCR4 expression in ischemic (IHD) and valvular (VHD) heart diseases.MethodsThe SDF-1 and inflammatory profile were analyzed by ELISA from plasma obtained bone marrow of ischemic heart patients (IHD, n = 41), valvular heart patients (VHD, n = 30) and healthy controls (C, n = 9). Flow cytometry was used to evaluate CXCR4 (CD184) expression on the surface of bone marrow cells, and the CXCR4 expression was estimated by real-time quantitative PCR.ResultsThe SDF-1 levels in the groups IHD, VHD and control were, respectively, 230, 530 and 620 pg/mL (P = 0.483), and was decreased in VHD patients using beta-blockers (263 pg/mL) when compared with other (844 pg/mL) (P = 0.023). Compared with IHD, the VHD group showed higher CXCR4 (P = 0.071) and CXCR7 (P = 0.082) mRNA expression although no difference in the level of CXCR4+ bone marrow cells was found between groups (P = 0.360).ConclusionIn conclusion, pathophysiological differences between IHD and VHD can affect the molecules involved in the activation of homing. In addition, the use of beta-blockers appears to interfere in this mechanism, a fact that should be considered in protocols that use BMC.

Integrin-Linked Kinase Controls Choroidal Neovascularization by Recruitment of Endothelial Progenitor Cells.

Vasculogenesis has been shown to contribute to the formation of choroidal neovascularization (CNV). However, the mechanism behind the recruitment of endothelial progenitor cells (EPC) to CNV is not well understood. Therefore, we were interested to know whether integrin-linked kinase (ILK) plays a role in recruiting EPC to CNV, and its possible mechanism. We investigated the effect of hypoxia on retinal pigment epithelium (RPE) cells expressing ILK, hypoxia-inducible factor 1α (HIF-1α), stromal-derived factor-1 (SDF-1), and vascular endothelial growth factor (VEGF), and we further examined the effect of ILK small interfering RNA (siRNA) on their expression. The function of ILK expressed by RPE on EPC in vitro with regard to angiogenic effect was also studied. In vivo, we determined the expression levels of the above factors in CNV. We also examined the role of ILK on their expression, on EPC recruiting, and on the growth of CNV. We found that hypoxia strongly induced the expression of ILK, HIF-1α, SDF-1, and VEGF. Moreover, the silencing of ILK attenuated their expression. It also decreased the phosphorylation of protein kinase B (PKB/AKT) and extracellular regulated protein kinases (ERK) and nearly abolished the proliferation, migration, and adhesion of EPC to RPE cells. In vivo, we showed that these factors were upregulated in CNV. Inhibiting the expression of ILK prohibited the "homing" of EPC to CNV lesions and attenuated the growth of CNV. We demonstrate that ILK controls the development of CNV by regulating the recruitment of EPC to CNV lesions, possibly through ILK-dependent expression of SDF-1 and VEGF in RPE.

SDF-1 improves wound healing ability of glucocorticoid-treated adipose tissue-derived mesenchymal stem cells

Glucocorticoids cause the delayed wound healing by suppressing inflammation that is required for wound healing process. Adipose tissue-derived mesenchymal stem cells (AT-MSCs) play an important role for wound healing by their cytokine productions including stromal derived factor 1 (SDF-1). However, it has not been clear how glucocorticoids affect the wound healing ability of AT-MSCs.In this study, we found that glucocorticoid downregulated SDF-1 expression in AT-MSCs. In addition, glucocorticoid-treated AT-MSCs induced less migration of inflammatory cells and impaired wound healing capacity compared with glucocorticoid-untreated AT-MSCs. Of note, prostaglandin E2 (PGE2) synthesis-related gene expression was downregulated by glucocorticoid and PGE2 treatment rescued not only SDF-1 expression in the presence of glucocorticoid but also their wound healing capacity in vivo. Furthermore, we found SDF-1-overexpressed AT-MSCs restored wound healing capacity even after treatment of glucocorticoid. Consistent with the results obtained from glucocorticoid-treated AT-MSCs, we found that AT-MSCs isolated from steroidal osteonecrosis donors (sAT-MSCs) who received chronic glucocorticoid therapy showed less SDF-1 expression and impaired wound healing capacity compared with traumatic osteonecrosis donor-derived AT-MSCs (nAT-MSCs). Moreover, the SDF-1 level was also reduced in plasma derived from steroidal osteonecrosis donors compared with traumatic osteonecrosis donors.These results provide the evidence that concomitant application of AT-MSCs with glucocorticoid shows impaired biological modulatory effects that induce impaired wound healing.

Effect of SDF-1/Cxcr4 Signaling Antagonist AMD3100 on Bone Mineralization in Distraction Osteogenesis.

Distraction osteogenesis (DO) is a widely applied technique in orthopedics surgery, which involves rapid stem cell migration, homing, and differentiation. Interactions between the chemokine receptor Cxcr4 and its ligand, stromal derived factor-1 (SDF-1), regulate hematopoietic stem cell trafficking to the ischemic area and induce their subsequent differentiation. Here, we examined SDF-1 expression and further investigated the role of SDF-1/Cxcr4 signaling antagonist AMD3100 during bone regeneration in rat DO model. The results showed that expression levels of SDF-1 and osteogenic genes were higher in DO zones than in the fracture zones, and SDF-1 expression level was the highest at the termination of the distraction phase. Radiological, mechanical, and histological analyses demonstrated that the local administration of AMD3100 (400μM) to DO rats significantly inhibited new bone formation. In the rat bone marrow mesenchymal stem cells culture, comparing to the group treated with osteogenic induction medium, AMD3100 supplement led to a considerable decrease in the expression of alkaline phosphatase and early osteogenic marker genes. However, the amount of calcium deposits in rat MSCs did not differ between the groups. Therefore, our study demonstrated that the DO process induced higher expression of SDF-1, which collated to rapid induction of callus formation. Local application of SDF-1/Cxcr4 signaling antagonist AMD3100 significantly inhibited bone mineralization and osteogenesis in DO, which may represent a potential therapeutic approach to the enhancement of bone consolidation in patients undergoing DO.

Stochastic Petri Net Modeling of Hypoxia Pathway Predicts a Novel Incoherent Feed-Forward Loop Controlling SDF-1 Expression in Acute Kidney Injury.

Homing of stem cells to the sites of injury is crucial for tissue regeneration. Stromal derived factor 1 (SDF-1) is among the most important chemokines recruiting these cells. Unexpectedly, our previous experimental data on mouse models of acute kidney injury showed that SDF-1 has a declining trend following ischemic kidney insult. To describe this unforeseen observation, a stochastic Petri net model of SDF-1 regulation in the hypoxia pathway was constructed based on main related components extracted from literature. Using this strategy, predictions regarding the underlying mechanisms of SDF-1 kinetics are generated and a novel incoherent feed forward loop regulating SDF-1 expression is proposed. The computational approach suggested here can be exploited to propose novel therapies for debilitating disorders such as kidney injury.

Transforming growth factor β-activated kinase 1 negatively regulates interleukin-1α-induced stromal-derived factor-1 expression in vascular smooth muscle cells

Stromal-derived Factor-1 (SDF-1) derived from vascular smooth muscle cells (VSMCs) contributes to vascular repair and remodeling in various vascular diseases. In this study, the mechanism underlying regulation of SDF-1 expression by interleukin-1α (IL-1α) was investigated in primary rat VSMCs. We found IL-1α promotes SDF-1 expression by up-regulating CCAAT-enhancer-binding protein β (C/EBPβ) in an IκB kinase β (IKKβ) signaling-dependent manner. Moreover, IL-1α-induced expression of C/EBPβ and SDF-1 was significantly potentiated by knockdown of transforming growth factor β-activated kinase 1 (TAK1), an upstream activator of IKKβ signaling. In addition, we also demonstrated that TAK1/p38 mitogen-activated protein kinase (p38 MAPK) signaling exerted negative effect on IL-1α-induced expression of C/EBPβ and SDF-1 through counteracting ROS-dependent up-regulation of nuclear factor erythroid 2-related factor 2 (NRF2). In conclusion, TAK1 acts as an important regulator of IL-1α-induced SDF-1 expression in VSMCs, and modulating activity of TAK1 may serve as a potential strategy for modulating vascular repair and remodeling.

SDF1-3′A polymorphism is associated with size but not occurrence of abdominal aortic aneurysm in a Chinese population

Previous studies have suggested that stromal-derived factor 1 (SDF1) plays a pivotal role in abdominal aortic aneurysm (AAA) development. The SDF1-3'A polymorphism (G to A, rs1801157), located in the 3' untranslated region, could influence the expression of SDF1. The aim of our study was to investigate the relationship of SDF1-3'A polymorphism with the risk of AAA occurrence and size. A total of 205 AAA patients and 216 age- and sex-matched controls were recruited. The SDF1-3'A polymorphism was evaluated by polymerase chain reaction, followed by restriction enzyme analysis. The frequency of A allele was similar between groups. The genotype distribution also displayed no statistically significant differences under both the dominant model (odds ratio [OR], 0.922; P= .678) and the recessive model (OR, 1.617; P= .300). The multiple logistic regression analysis indicated that the association between the polymorphism and AAA remained insignificant when applied to the dominant model. However, AAA patients with GG genotype were more likely to develop aneurysms larger than 50mm (OR, 0.497; P= .014). AAA patients with SDF1-3'A allele have reduced plasma SDF1α levels. In addition, plasma SDF1α levels were positively correlated with AAA size. Our study suggests that SDF1-3'A polymorphism is associated with size but not occurrence of AAA, providing further evidence that SDF1 is implicated in AAA progression.

Reduced expression of osteonectin and increased natural killer cells may contribute to the pathophysiology of aplastic anemia.

Normal hematopoiesis involves complex interactions between hematopoietic cells and the bone marrow (BM) microenvironment. The exact causes and mechanisms involved in aplastic anemia (AA) are not known. For better understanding of the pathophysiology of AA, we investigated changes in the hematopoietic stem cell (HSC) compartment and the BM microenvironment in patients with AA by immunohistochemical analysis. A total of 10 AA patients and 10 controls were enrolled. Using BM biopsy specimen, we performed immunohistochemistry for osteopontin, osteonectin, osteocalcin, nestin, stromal-derived factor-1 (SDF-1), lymphocytes, macrophage, and HSCs. Numbers of HSCs and T/B lymphocytes were significantly lower in the AA specimens than the controls, and the AA specimens contained more natural killer cells (CD56(+) cells) (P < 0.01). The 2 groups had similar levels of expression of osteopontin, osteocalcin, nestin, and SDF-1. However, the number of osteonectin(+) cells in the AA specimens was significantly lower than in the control specimens (P<0.01). Our findings support the hypothesis that defects in the stromal cells contribute to the pathogenesis of AA by damaging HSC niche. Immune-mediated natural killer cells may also play a role in the pathogenesis of AA.

Injection of Cardiac Stem Cells Prolongs the Survival of Cardiac Allograft Rats

Cardiac c-kit+cells isolated from cardiac explant-derived cells modestly improve cardiac functions after myocardial infarction; however, their full potential has not yet been realized. The present study was undertaken to determine the isolation and culture of c-kit+cardiac stem cells (CSCs), and the roles of myocardial injection of CSCs on the survival of rat cardiac allograft. Recipient Sprague–Dawley rats were transplanted with hearts from Wistar rats. in the in vitro experiment, c-kit+cells were isolated from mouse heart fragment culture by magnetic cell sorting. CSCs expressed of cardiomyocyte specific protein cardiac troponin I, α smooth muscle actin and von Willebrand factor in conditioned culture. CsC injection increased graft survival of cardiac allograft rats. The effects of CSCs on increase in graft survival of cardiac allograft rats were blocked by stromal-derived factor-1 (SDF-1) knockdown. The expression of SDF-1 was increased after CSC injection into the cardiac of cardiac allograft rats. These results indicate that CSC injection into the cardiac prolongs graft survival of cardiac allograft rats. SDF-1 plays an important role in the effects of CSCs on the graft survival of cardiac allograft rats.

Abstract PR14: In vivo targeting of stromal-derived factor-1 as a strategy to prevent myeloma cell dissemination to distant bone marrow niches

Abstract Background. Multiple myeloma (MM) patients present with multiple lytic lesions at diagnosis, indicating the presence of continuous dissemination of MM cells from the primary site of tumor development to multiple distant bone marrow (BM) niches. We hypothesized that stromal-derived factor-1 (SDF1) may represent a target for preventing transition from MGUS (micrometastatic-stage) to active-MM (macrometastatic-stage). We therefore evaluated SDF1 expression in the BM of patients with MGUS, MM, compared to healthy individuals; and tested NOX-A12, a high affinity L-oligonucleotide binder to SDF1, looking at its ability to modulate MM cell tumor growth and homing to the BM in vivo and in vitro. Methods. SDF1 levels were evaluated by immunohistochemistry on BM specimens of patients with MGUS, active-MM, or healthy individuals; and confirmed by ELISA, using conditioned-medium of BM-mesenchymal stromal cells (BM-MSCs) from MGUS, active-MM and healthy individuals. BM metastatic lesions from primary epithelial tumors were also evaluated. Co-localization of SDF1 with MM cell (MM.1S-GFP+)-enriched BM niches was evaluated using in vivo confocal microscopy. Effect of NOX-A12 on modulating MM cell dissemination was tested in vivo, by using in vivo MM metastasis model. In vivo homing and in vivo tumor growth of MM cells (MM.1S-GFP+/luc+) was assessed by using in vivo confocal microscopy and bioluminescence, in mice treated with 1) vehicle; 2) NOX-A12; 3) bortezomib; 4) NOX-A12+bortezomib. Effects of drug combination on dissemination of MM cells to distant BM niches was evaluated ex vivo by immunofluorescence on explanted femurs. DNA synthesis and adhesion of MM cells in the context of NOX-A12 treated primary MM BM-MSCs in presence or absence of bortezomib were tested by thymidine uptake and adhesion in vitro assay, respectively. Synergism was calculated by using CalcuSyn software. Results. Patients with active-MM present with higher BM SDF1 expression vs MGUS patients and healthy individuals. Similarly, BM presenting with metastasis from epithelial primary tumors had higher SDF1 levels compared to healthy subjects, thus suggesting the importance of SDF1 in favoring tumor cell metastasis to BM niches. SDF1 co-localized at BM level with MM tumor cells in vivo. In vitro, NOX-A12 induced a dose-dependent de-adhesion of MM cells from the BMSCs supported by inhibition of BM-MSC-mediated phosphorylation of ERK1/2 and cofilin. Importantly, NOX-A12 induced MM cell mobilization from the BM to the peripheral blood (PB) as shown ex vivo by reduction of MM cells in the BM and increased number of MM cells within the PB compared to control mice (P&amp;lt;.05). This was supported by inhibited homing and dissemination of MM cells to the BM of those mice pre-treated with NOX-A12. NOX-A12 enhanced MM cell sensitivity to bortezomib, in vivo: tumor burden was similar between NOX-A12- and control mice whereas bortezomib-treated mice showed significant reduction in tumor growth vs. control (P&amp;lt;.05); importantly, significant reduction of tumor burden in those mice treated with sequential administration of NOX-A12 and bortezomib was observed, compared to bortezomib-treated mice (P &amp;lt;.05). Similarly, NOX-A12+bortezomib combination induced significant inhibition of MM cell homing, as shown by in vivo confocal microscopy. In vitro studies confirmed synergism between NOX-A12 and bortezomib in modulating MM cell survival and adhesion to BM-MSCs. Conclusion. SDF-1 represents a valid target for inhibiting MM cell dissemination to distant BM niches, thus providing the evidence for using the SDF1 inhibiting spiegelmer NOX-A12 to target MM cells at the stage of micrometastasis (MGUS), thus preventing development of macrometastatic MM. This abstract is also presented as Poster B80. Citation Format: Aldo M. Roccaro, Antonio Sacco, Michele Moschetta, Patricia Maiso, Yuji Mishima, Yosra Aljawai, Fabio Facchetti, Anna Kruschinski, Giuseppe Rossi, Irene M. Ghobrial. In vivo targeting of stromal-derived factor-1 as a strategy to prevent myeloma cell dissemination to distant bone marrow niches. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr PR14. doi:10.1158/1538-7445.CHTME14-PR14