KAI1(CD82) is a key molecule to control angiogenesis and switch angiogenic milieu to quiescent state

BACKGROUND

Little is known about endogenous inhibitors of angiogenic growth factors. In this study, we identified a novel endogenous anti-angiogenic factor expressed in pericytes and clarified its underlying mechanism and clinical significance.

METHODS

Herein, we found Kai1 knockout mice showed significantly enhanced angiogenesis. Then, we investigated the anti-angiogenic roll of Kai1 in vitro and in vivo.

RESULTS

KAI1 was mainly expressed in pericytes rather than in endothelial cells. It localized at the membrane surface after palmitoylation by zDHHC4 enzyme and induced LIF through the Src/p53 pathway. LIF released from pericytes in turn suppressed angiogenic factors in endothelial cells as well as in pericytes themselves, leading to inhibition of angiogenesis. Interestingly, KAI1 had another mechanism to inhibit angiogenesis: It directly bound to VEGF and PDGF and inhibited activation of their receptors. In the two different in vivo cancer models, KAI1 supplementation significantly inhibited tumor angiogenesis and growth. A peptide derived from the large extracellular loop of KAI1 has been shown to have anti-angiogenic effects to block the progression of breast cancer and retinal neovascularization in vivo.

CONCLUSIONS

KAI1 from PC is a novel molecular regulator that counterbalances the effect of angiogenic factors.

CD82/KAI1 Maintains the Dormancy of Long-Term Hematopoietic Stem Cells through Interaction with DARC-Expressing Macrophages

Hematopoiesis is regulated by crosstalk between long-term repopulating hematopoietic stem cells (LT-HSCs) and supporting niche cells in the bone marrow (BM). Here, we examine the role of CD82/KAI1 in niche-mediated LT-HSC maintenance. We found that CD82/KAI1 is expressed predominantly on LT-HSCs and rarely on other hematopoietic stem-progenitor cells (HSPCs). In Cd82(-/-) mice, LT-HSCs were selectively lost as they exited from quiescence and differentiated. Mechanistically, CD82-based TGF-β1/Smad3 signaling leads to induction of CDK inhibitors and cell-cycle inhibition. The CD82 binding partner DARC/CD234 is expressed on macrophages and stabilizes CD82 on LT-HSCs, promoting their quiescence. When DARC(+) BM macrophages were ablated, the level of surface CD82 on LT-HSCs decreased, leading to cell-cycle entry, proliferation, and differentiation. A similar interaction appears to be relevant for human HSPCs. Thus, CD82 is a functional surface marker of LT-HSCs that maintains quiescence through interaction with DARC-expressing macrophages in the BM stem cell niche.

Abstract P120: Improving the Angiogenic Abilities of Mobilized Peripheral Blood Stem Cells Achieved by Priming with Activated Platelet Supernatant for Regenerative Cell Therapy

Platelets play a critical role in hemostasis and also have ability to promote angiogenesis and tissue repair by secreting of numerous cytokine and making angiogenic condition. We investigated whether autologous ‘activated platelet supernatant (APS)’ has effect on enhancing pro-angiogenic potential of peripheral blood stem cells (PBSC) for stem cell-based therapy for ischemic diseases. Granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood stem cells (mobPBSC) were isolated from healthy volunteers, while APS was collected from platelet rich plasma by thrombin activation. mobPBSCs were primed with APS (APS primed mobPBSCs) for 6 hours, and APS primed mobPBSCs characterized their angiogenic ability. For the safety analysis, we estimated the thrombogenicity of platelets in whole blood mixed with APS primed mobPBSCs by expression of glycoprotein IIb and IIIa on platelets. APS had a higher level of various cytokines, such as IL8, IL17, PDGF and VEGF than naïve platelet supernatants. And APS primed mobPBSCs had more expression of angiogenic factors, surface markers (i.e. CD34, CD31, and CXCR4) and integrins (integrin α5, β1 and β2) than Veh primed and Pre primed mobPBSC. Also APS primed mobPBSCs were polarized toward CD14++/CD16+ pro-angiogenic monocytes. And result in adhesion to endothelial cells and fibronectin which represents cell to cell and cell to extracellular matrix adhesion, respectively. The culture supernatant of APS-primed mobPBSCs contained high levels of IL8, IL10, IL17 and TNFα, and augmented proliferation and capillary network formation of HUVEC. In-vivo transplantation of APS-primed mobPBSC into athymic mice ischemic hindlimbs and Matrigel plugs elicited vessel differentiation and tissue repair. In thrombogenicity test, platelet activity increased after mixing whole blood with mobPBSC regardless of the priming agent. However, this was reduced by pretreatment of aspirin, which is an antiplatelet agent prescribed to patients with ischemic diseases. Our data demonstrate that mobPBSCs primed with APS improve angiogenic potential, and that can be adjunctive strategy to enhance the efficiency of stem cell therapy for ischemic diseases.

Cross-cultural adaptation and validation of the Korean Toronto Extremity Salvage Score for extremity sarcoma

BACKGROUND

A Korean version of Toronto Extremity Salvage Score (TESS), a widely used disease-specific patient-reported questionnaire for assessing physical function of sarcoma patients, has not been developed.

OBJECTIVES

1) to translate and cross-culturally adapt the TESS into Korean, and 2) to examine its comprehensibility, reliability and validity.

METHODS

TESS was translated into Korean, then translated back into English, and reviewed by a committee to develop the consensus version of the Korean TESS. The Korean TESS was administered to 126 patients to examine its comprehensibility, reliability, and validity.

RESULTS

Comprehensibility was high, as the patients rated questions as "easy" or "very easy" in 96% for the TESS lower extremity (LE) and in 97% for the TESS upper extremity (UE). Test-retest reliability with intraclass coefficient (0.874 for LE and 0.979 for UE) and internal consistency with Cronbach's alpha (0.978 for LE and 0.989 for UE) were excellent. Korean TESS correlated with the MSTS score (r = 0.772 for LE and r = 0.635 for UE), and physical functioning domain of EORTC-CLQ C30 (r = 0.840 for LE and r = 0.630 for UE).

CONCLUSION

Our study suggests that Korean version of the TESS is a comprehensible, reliable, and valid instrument to measure patient-reported functional outcome in patients with extremity sarcoma.

Erythropoietin priming improves the vasculogenic potential of G-CSF mobilized human peripheral blood mononuclear cells

AIMS

From our previous clinical trials, intracoronary infusion of granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells ((mob)PBMCs) proved to be effective in improving myocardial contractility and reducing infarct volume in acute myocardial infarction. We tested the effect of priming (mob)PBMCs with erythropoietin (EPO) to augment its therapeutic efficacy.

METHODS AND RESULTS

(mob)PBMCs were obtained from healthy volunteers after a 3-day subcutaneous injection of G-CSF (10 μg/kg). About 40% of (mob)PBMCs were EPO receptor (EPOR) (+) and responded to 6 h EPO-priming (10 IU/mL) by increasing the expression of vasculogenic factors (i.e. IL8, IL10, bFGF, PDGF, MMP9) and adhesion molecules (i.e. integrin αV, β1, β2, β8) through the JAK2 and Akt pathway. These responses were also observed in PBMCs from elderly patients with coronary disease. The conditioned media from EPO-primed (mob)PBMCs contained various cytokines such as IL8, IL10, TNFα, and PDGF, which enhanced the migration and tube formation capability of endothelial cells. EPO-primed (mob)PBMCs also showed increased adhesion on endothelial cells or fibronectin. Augmented vasculogenic potential of EPO-primed (mob)PBMCs was confirmed in a Matrigel plug assay, ischaemic hindlimb, and myocardial infarction models of athymic nude mice. There were two action mechanisms: (i) cellular effects confirmed by direct incorporation of human (mob)PBSCs into mouse vasculature and (ii) indirect humoral effects confirmed by the therapeutic effect of the supernatant of EPO-primed (mob)PBMCs.

CONCLUSION

Brief ex vivo EPO-priming is a novel method to augment the vasculogenic potential of human (mob)PBMCs, which would help to achieve better results after intracoronary infusion in myocardial infarction patients.

Activated platelet supernatant can augment the angiogenic potential of human peripheral blood stem cells mobilized from bone marrow by G-CSF

Platelets not only play a role in hemostasis, but they also promote angiogenesis and tissue recovery by releasing various cytokines and making an angiogenic milieu. Here, we examined autologous 'activated platelet supernatant (APS)' as a priming agent for stem cells; thereby enhance their pro-angiogenic potential and efficacy of stem cell-based therapy for ischemic diseases. The mobilized peripheral blood stem cells ((mob)PBSCs) were isolated from healthy volunteers after subcutaneous injection of granulocyte-colony stimulating factor. APS was collected separately from the platelet rich plasma after activation by thrombin. (mob)PBSCs were primed for 6h before analysis. Compared to naive platelet supernatants, APS had a higher level of various cytokines, such as IL8, IL17, PDGF and VEGF. APS-priming for 6h induced (mob)PBSCs to express key angiogenic factors, surface markers (i.e. CD34, CD31, and CXCR4) and integrins (integrins α5, β1 and β2). Also (mob)PBSCs were polarized toward CD14(++)/CD16(+) pro-angiogenic monocytes. The priming effect was reproduced by an in vitro reconstruction of APS. Through this phenotype, APS-priming increased cell-cell adhesion and cell-extracellular matrix adhesion. The culture supernatant of APS-primed (mob)PBSCs contained high levels of IL8, IL10, IL17 and TNFα, and augmented proliferation and capillary network formation of human umbilical vein endothelial cells. In vivo transplantation of APS-primed (mob)PBSCs into athymic mice ischemic hindlimbs and Matrigel plugs elicited vessel differentiation and tissue repair. In safety analysis, platelet activity increased after mixing with (mob)PBSCs regardless of priming, which was normalized by aspirin treatment. Collectively, our data identify that APS-priming can enhance the angiogenic potential of (mob)PBSCs, which can be used as an adjunctive strategy to improve the efficacy of cell therapy for ischemic diseases.

Highly angiogenic CXCR4(+)CD31(+) monocyte subset derived from 3D culture of human peripheral blood

Ex vivo expansion of human circulating angiogenic cells is a major challenge in autologous cell therapy for ischemic diseases. Here, we demonstrate that hematosphere-derived CXCR4(+)CD31(+) myeloid cells using peripheral blood possess robust proangiogenic capacity such as formation of vessel-like structures and tip cell-like morphology in Matrigel. We also found that CD31 positive myeloid cells are principal cellular component of hematospheres by magnetic cell sorting. Flow cytometry analysis showed that fresh peripheral blood contained 40.3 ± 15.2% of CXCR4(+)CD31(+) myeloid cells, but at day 5 of hematosphere culture, most of myeloid cells were CXCR4(+)CD31(+) by 86.9 ± 5.4%. Hematosphere culture significantly increased the production of angiogenic niche-supporting cytokines. Moreover, CD31-homophilic interaction and VEGF-VEGF receptor loop signaling were essential for sphere formation and acquisition of angiogenic capacity in hematospheres. Matrigel plug and ischemic hindlimb model provide in vivo evidence that hematosphere-derived myeloid cells have highly vasculogenic capacities, participate in new and mature vessel formation, and exert therapeutic effects on ischemic hindlimb. In conclusion, our strategy for ex vivo expansion of human CXCR4(+)CD31(+) angiogenic cells using hematospheres provides an autologous therapeutic cell source for ischemic diseases and a new model for investigating the microenvironment of angiogenesis.

New method to differentiate human peripheral blood monocytes into insulin producing cells: Human hematosphere culture

Strategy to differentiate stem cells into insulin producing cells (IPCs) in vitro has been a promising one to get cell source of β-cell replacement therapy for diabetes. It has been suggested that islets and neurons share features and nestin-positive cells could differentiate into IPCs. We have recently developed a three-dimensional culture system using human peripheral blood cells named as blood-born hematosphere (BBHS). Here we showed that most of BBHS were composed of nestin-positive cells. Under the four-stage differentiation protocol for IPCs, we plated nestin-positive BBHS onto fibronectin-coated dish. These cells form islet-like clusters and most of them expressed insulin. Pancreatic specific genes were turned on, such as transcription factors (Pdx-1, Ngn3 and Nkx6.1), genes related to endocrine function (Glut-2 and PC2) or β cell function (Kir6.2, SUR1). Furthermore islet differentiation was confirmed by dithizone (DTZ) staining to detect zinc ion which binds insulin protein within the cells. Finally, IPCs derived from BBHS showed capability to secrete insulin in response to glucose stimulation. Taken together, our novel protocol successfully induced islet-like human insulin producing cells out of BBHS. This strategy of ex vivo expansion of IPCs using BBHS provides an autologous therapeutic cell source for the treatment of diabetes.

Pantothenate kinase-associated neurodegeneration in Korea: recurrent R440P mutation in PANK2 and outcome of deep brain stimulation

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the mutation status of PANK2 among Korean patients with pantothenate kinase-associated neurodegeneration (PKAN) and to document the outcome of pallidal deep brain stimulation (DBS).

METHODS

Direct sequencing and deletion/duplication analysis of PANK2 were conducted in 12 patients (11 unrelated) with PKAN, diagnosed on the basis of extrapyramidal dysfunction and the 'eye-of-the-tiger sign' on brain magnetic resonance imaging (MRI). Pallidal DBS was conducted in four patients, and the outcomes were measured using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS).

RESULTS

A PANK2 mutation was identified in both alleles in all patients. The most prevalent mutation was c.1319G>C (p.R440P) in 8/22 mutated alleles (36%). An intragenic deletion ranging from exons 2 to 4 was found in one allele (1/22, 4.5%) using deletion/duplication analysis. The outcome of pallidal DBS was favorable in two patients with atypical PKAN and moderate severity of dystonia. However, two patients with typical PKAN and relatively severe symptoms showed variable responses.

CONCLUSIONS

The c.1319G>C (p.R440P) mutation appears to be a founder genotype among Korean patients with PKAN. Furthermore, this study provides additional data for the recent international effort to evaluate the efficacy of pallidal DBS in the treatment of patients with PKAN.

Transforming growth factor beta receptor II (TGFBR2) polymorphisms and the association with nonsegmental vitiligo in the Korean population

The precise cause of vitiligo is unknown. However, autoimmunity is considered the most likely aetiology, especially in nonsegmental vitiligo (NSV). In this study we determined whether or not the transforming growth factor beta receptor II (TGFBR2) gene contributes to susceptibility for NSV in the Korean population. Blood samples were collected from 415 controls and 233 cases. We selected three single nucleotide polymorphisms (SNPs) in the TGFBR2 gene. The genotypes of the SNPs were determined using direct sequencing. All of the SNPs were significantly different between the vitiligo patients and controls (rs2005061, co-dominant, dominant, recessive, P < 0.05; rs3773645, co-dominant, dominant, recessive, P < 0.05; rs3773649, co-dominant, recessive, P < 0.05). In addition, haplotype 1 (CG) and haplotype 2 (GA) of the linkage disequilibrium (LD) block were also associated with a risk of NSV. The present study suggests that TGFBR2 might be related to NSV.

Determination of low (137)Cs concentration in seawater using ammonium 12-molybdophosphate adsorption and chemical separation method

A new method has been developed for analyzing (137)Cs in a small volume of seawater. Ammonium 12-molybdophosphate (AMP) was used two times during pretreatment procedure. The first step was to adsorb (137)Cs in seawater samples into AMP in order to reduce sample volume, and the second was to remove (87)Rb, interference nuclide for beta counting. The AMP adsorbing (137)Cs was dissolved by sodium hydroxide solution, and then (137)Cs was finally formed to be cesium chloroplatinate precipitate by adding 10% hexachloroplatinic acid. The beta rays emitted from (137)Cs were measured with a low background gas-proportional alpha/beta counter. This method was applied to several seawater samples taken in the East Sea of Korea. Compared to the routinely used gamma-spectrometry method, this new AMP method was reliable and suitable for analyzing (137)Cs in deep seawater.

Immortalization of human embryonic fibroblasts by overexpression of c-myc and simian virus 40 large T antigen

SV40 large T antigen, a viral oncoprotein, is known to immortalize human diploid fibroblast by soaking up cellular RB and p53, but its frequency is extremely low. Additional genetic alteration is necessary for single-step immortalization. We attempted to find out what this alteration is by overexpressing cellular signal mediator genes; c-myc and cyclin D frequently amplified in many cancer cells. Overexpression of cyclin D did not affect the immortalization, but, overexpression of c-myc along with T antigen could immortalize normal human diploid fibroblast. Several cellular markers tested during immortalization process showed that p21, a cyclin-dependent kinase inhibitor and a marker of cellular senescence, disappeared in the life span-extended cells by T antigen and in the immortalized cells by c-myc. p21 was, however, elevated in the senescent cells and in the cells of crisis. Interestingly, p16 was upregulated whenever T antigen is overexpressed. Telomerase activity was also activated only in the immortalized cells. These results suggest that overexpression of c-myc contributes to immortalization of human diploid fibroblast by activating telomerase activity and suppressing p21 activity.

Novel anti-calcification treatment of biological tissues by grafting of sulphonated poly(ethylene oxide)

Biological porcine tissue was modified by the direct coupling of sulphonated poly(ethylene oxide) (PEO-SO3) containing amino acid end groups after glutaraldehyde fixation. The calcification of the modified tissue [bioprosthetic tissue (BT)-PEO-SO3] and control (BT control) was investigated by in vivo rate subdermal, canine aorta-illiac shunt and right ventricle-pulmonary artery shunt implantation models. Less calcium deposition of BT-PEO-SP3 than of BT control was observed in in vivo tests. Such a reduced calcification of BT-PEO-SO3 can be explained by decreases of residual glutaraldehyde groups, a space filling effect and, therefore, improved biostability and synergistic blood-compatible effects of PEO and SO3 groups after the covalent binding of PEO-SO3 to tissue. This simple method can be a useful anti-calcification treatment for implantable tissue valves.

Chemical modification of implantable biologic tissue for anti-calcification

Biologic porcine tissue was modified by coupling sulfonated polyethyl-eneoxide (PEO-SO3) and the effect of modification on calcification was evaluated in vitro and in vivo. The modification process involves grafting PEO-SO3 to porcine valve leaflet either by carbodiimide (EDC) activation or by direct coupling using glutaraldehyde. Thermal property, measured by differential scanning calorimetry, showed that the shrinkage temperature of modified tissue increased compared with control tissue and fresh tissue, suggesting increased thermal stability. Resistance to collagenase digestion revealed that modified tissues have greater resistance to enzyme digestion than do control tissues. In vitro calcification showed that modified tissues have less calcium deposition than do control tissues. In vivo calcification, using a rat subcutaneous implantation model, also showed less calcification of modified tissue than that of control. The resistance of modified tissue to collagenase, higher shrinkage temperature, and reduced calcification, when compared with control tissue, attest to the usefulness of this chemical modification for implantable biologic tissue.