-
[show abstract]
[hide abstract]
ABSTRACT: OBJECTIVE: Although endothelial progenitor cells (EPCs) have been reported to promote neovessel formation during vascular injury, the function of supporting cells of EPCs and their interaction with EPCs during EPC isolation remain unclear. APPROACH AND RESULTS: We investigated the functional properties of 2 types of EPCs, also known as endothelial colony-forming cells (ECFCs), CD34(-)/CD34(+) cell-derived ECFCs (hybrid-dECFCs) and CD34(+) cell-derived ECFCs (stem-dECFCs), isolated using different methods, to elucidate the role of CD34(-) cell populations as cell-supporting niches. Using EPC colony-forming and insert coculture assays, we found that CD34(-) accessory cells dynamically modulate hematopoietic stem cell-derived endothelial cell progenitor commitment via angiogenic cytokines secreted by CD34(-)/CD11b(+) macrophages. On the basis of these findings, we isolated 2 types of ECFCs and investigated their bioactivities. We found that stem-dECFCs showed remarkably retarded cell growth, enhanced senescence, and decreased characteristics of ECFCs, whereas hybrid-dECFCs showed greater proliferative properties but delayed senescence. In a murine hind-limb ischemia model, hybrid-dECFCs showed significantly enhanced blood perfusion, capillary density, transplanted cell survival and proliferation, and angiogenic cytokine secretion compared with stem-dECFCs. In particular, the migratory capacity of hybrid-dECFCs was significantly enhanced, in part mediated via an augmented phosphorylation cascade of focal adhesion kinase and Src, resulting in a highly increased incorporation capacity of hybrid-dECFCs compared with stem-dECFCs. CD34(-) accessory cells of hybrid-dECFCs might be niche-supporting cells that facilitate cell survival, increase the secretion of angiogenic cytokines, and increase incorporation. CONCLUSIONS: This study provided important insight into blood vessel formation and repair in ischemic diseases for ECFC-based cell therapy.
Arteriosclerosis Thrombosis and Vascular Biology 05/2013; · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Human blood-derived CD133(+) cell populations, which are believed to represent a hematopoietic/endothelial progenitor fraction, have the ability to promote the repair of injured spinal cord in animal models. However, the mechanisms by which CD133(+) cell transplantation promotes spinal cord regeneration remain to be clarified. Another possible hurdle on the way to clinical applicability of these cells is their scarce representation in the overall population of mononuclear cells. We therefore analyzed and compared ex-vivo expanded human cord blood derived CD133(+) cells with freshly isolated CD133(+) cells as well as corresponding CD133(-) control mononuclear cells in respect to their ability to promote spinal cord repair using in vitro assays and cell transplantation into a mouse spinal cord injury model. In vitro, expanded cells as well as fresh CD133(+) cells formed endothelial progenitor cell (EPC) colonies, whereas CD133(-) cells formed no EPC colonies. In vivo, the administration of fresh CD133(+) and expanded cells enhanced angiogenesis, astrogliosis, axon growth and functional recovery after injury. In contrast, the administration of CD133(-) cells failed to promote axon growth and functional recovery, but moderately enhanced angiogenesis and astrogliosis. In addition, high-dose administration of expanded cells was highly effective in the induction of regenerative processes at the injured spinal cord.
Journal of the neurological sciences 03/2013; · 2.32 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: INTRODUCTION: Endothelial progenitor cells (EPCs) play a critical role in restoration of ischemic diseases. However, the actual status of EPC development and the mechanisms of EPC dysfunctions in patients with various ischemic diseases remain unknown. METHODS: To investigate the detailed function of EPCs in experimental murine models, we have established an EPC colony forming assay (EPC-CFA) in murine EPCs. The abilities of murine EPCs in differentiation, adhesive capacity, proliferative potency, and transplantation in vitro and in vivo were then examined. RESULTS: Peripheral blood mononuclear cells (PB-MNCs), bone marrow mononuclear cells (BM-MNCs) or bone marrow c-Kit+/Sca-1+ lineage negative (BM-KSL) cells differentiated into two types of EPC colony forming units (EPC-CFUs), large sized EPC (large-EPC)-CFUs and small sized EPC (small-EPC)-CFUs. Gene expression analysis demonstrated that both EPC-CFU-derived cells expressed eNOS, Flk-1 and VE-cadherin, markers of endothelial cells (ECs), although the small-EPCs derived from small-EPC-CFU was higher number and showed more immature features (higher population of KSL cells). Functionally, the large-EPCs derived from large-EPC-CFU had higher adhesive capacity but lower proliferative potency than small-EPCs, showing improved tubular forming capacity and incorporation potency into primary EC-derived tube formation. Importantly, hindlimb ischemia increased the frequencies of large-EPC-CFUs differentiated from PB-MNCs and bone marrow. Actually, transplantation of large-EPCs into ischemic hindlimb enhanced neovascularization in hindlimb ischemia model, although small-EPCs or murine ECs did not, suggesting that large-EPC-CFUs might play an important role in restoration of ischemic diseases. CONCLUSIONS: We demonstrated using a murine ischemia model that the EPC-CFA could be a useful way to investigate the differentiation levels of murine EPCs, further providing a crucial clue that large-EPC-CFU status may be more functional or effective EPCs to promote neovascularization.
Stem Cell Research & Therapy 02/2013; 4(1):20. · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spinal cord injury causes initial mechanical damage, followed by ischemia-induced, secondary degeneration, worsening the tissue damage. Although endothelial progenitor cells (EPCs) have been reported to play an important role for pathophysiological neovascularization in various ischemic tissues, the EPC kinetics following spinal cord injury have never been elucidated. In this study, we therefore assessed the in vivo kinetics of bone marrow-derived EPCs by EPC colony-forming assay and bone marrow transplantation from Tie2/lacZ transgenic mice into wild-type mice with spinal cord injury. The number of circulating mononuclear cells and EPC colonies formed by the mononuclear cells peaked at day 3 postspinal cord injury. Bone marrow transplantation study revealed that bone marrow-derived EPCs recruited into the injured spinal cord markedly increased at day 7, when neovascularization and astrogliosis drastically occurred in parallel with axon growth in the damaged tissue. To elucidate further the contribution of EPCs to recovery after spinal cord injury, exogenous EPCs were systemically infused immediately after the injury. The administered EPCs were incorporated into the injured spinal cord and accelerated neovascularization and astrogliosis. These findings suggest that bone marrow-derived EPCs may contribute to the tissue repair by augmenting neovascularization and astrogliosis following spinal cord injury. © 2012 Wiley Periodicals, Inc.
Journal of Neuroscience Research 09/2012; 90(12):2281-92. · 2.74 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Accumulating evidence suggests that Ginsenoside Rg3 appears to inhibit tumor growth including Lewis lung carcinoma, intestinal adenocarcinomas or B16 melanoma by inhibiting cell proliferation, tumor cell invasion and metastasis. Endothelial progenitor cells (EPCs) appear to play a key role in the growth of early tumors by intervening with the angiogenic switch promoting tumor neovessel formation by producing angiogenic cytokines during tumor progression. This paper reports a novel mechanism of Ginsenoside Rg3, a candidate anticancer bio-molecule, on tumor angiogenesis by inhibiting the multiple bioactivities of EPCs. When Ginsenoside Rg3 was applied to the ex vivo cultured outgrowth ECs, a type of EPCs, it inhibited the cell proliferation, cell migration and tubular formation of EPCs. Importantly, Ginsenoside Rg3 attenuated the phosphorylation cascade of the VEGF dependent p38/ERK signaling in vitro. The xenograft tumor model clearly showed that Ginsenoside Rg3 suppresses tumor growth and tumor angiogenesis by inhibiting the mobilization of EPCs from the bone marrow microenvironment to the peripheral circulation and modulates VEGF-dependent tumor angiogenesis. In conclusion, this study provides a potential therapeutic molecule, Ginsenoside Rg3, as an anticancer drug by inhibiting the EPC bioactivities.
Cancer biology & therapy 05/2012; 13(7):504-15. · 2.64 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Interactions between endothelial and neural stem cells are believed to play a critical role in the kinetics of neural stem cells in the central nervous system. Here we demonstrate that endothelial progenitor cells promote the repair of injured spinal cord through the induction of Notch-dependent astrogliosis and vascular regulation. The transplantation of Jagged1(+/+) endothelial progenitor cells, but not Jagged1(-/-) endothelial progenitor cells, increased the number of reactive astrocytes during the acute phase, and improved functional recovery following spinal cord injury. Expression of the Notch effector Hes5 was upregulated in the injured spinal cord after Jagged1(+/+) endothelial progenitor cell transplantation. Furthermore, we found that the Notch ligand Delta-like-1 was highly expressed in Jagged1(-/-) endothelial progenitor cells. Transplantation of Delta-like-1, as well as Jagged1-overexpressing 3T3 cells, revealed that only Jagged1-overexpressing 3T3 stromal cells enhanced astrogliosis following spinal cord injury. In addition, Jagged1(+/+) endothelial progenitor cells exhibited not only dramatic pro-angiogenic effects, but also morphologically abnormal vessel stabilization, compared with Jagged1(-/-)endothelial progenitor cells in injured spinal cord. Thus, transplanted endothelial progenitor cells promote astrogliosis, vascular regulation, and spinal cord regeneration through activation of Jagged1-Notch signaling.
Journal of neurotrauma 03/2012; 29(9):1758-69. · 4.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Endothelial progenitor cells (EPCs) contribute to the tumor vasculature during tumor progression. Decursin isolated from the herb Angelica gigas is known to possess potent anti-inflammatory activities. Recently, we reported that decursin is a novel candidate for an angiogenesis inhibitor [Jung et al., 2009]. In this study, we investigated whether decursin regulates EPC differentiation and function to inhibit tumor vasculogenesis. We isolated AC133+ cells from human cord blood and decursin significantly decreased the number of EPC colony forming units of human cord blood-derived AC133+ cells that produce functional EPC progenies. Decursin dose-dependently decreased the cell number of EPC committing cells as demonstrated by EPC expansion studies. Decursin inhibited EPC differentiation from progenitor cells into spindle-shaped EPC colonies. Additionally, decursin inhibited proliferation and migration of early EPCs isolated from mouse bone marrow. Furthermore, decursin suppressed expression of angiopoietin-2, angiopoietin receptor Tie-2, Flk-1 (vascular endothelial growth factor receptor-2), and endothelial nitric oxide synthase in mouse BM derived EPCs in a dose-dependent manner. Decursin suppressed tube formation ability of EPCs in collaboration with HUVEC. Decursin (4 mg/kg) inhibited tumor-induced mobilization of circulating EPCs (CD34 + /VEGFR-2+ cells) from bone marrow and early incorporation of Dil-Ac-LDL-labeled or green fluorescent protein (GFP)+ EPCs into neovessels of xenograft Lewis lung carcinoma tumors in wild-type- or bone-marrow-transplanted mice. Accordingly, decursin attenuated EPC-derived endothelial cells in neovessels of Lewis lung carcinoma tumor masses grown in mice. Together, decursin likely affects EPC differentiation and function, thereby inhibiting tumor vasculogenesis in early tumorigenesis.
Journal of Cellular Biochemistry 02/2012; 113(5):1478-87. · 2.87 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The Notch signaling pathway is evolutionarily conserved and has been associated with numerous developmental processes, including stem cell maintenance and adult tissue homeostasis. Notably, both abnormal increases and deficiencies of Notch signaling result in human developmental anomalies and cancer development implying that the precise regulation of the intensity and duration of Notch signals is imperative. Numerous studies have demonstrated that the aberrant gain or loss of Notch signaling pathway components is critically linked to multiple human diseases. In this chapter, we will briefly summarize the molecular basis of Notch signaling, focusing on the modulation of Notch signals, and its developmental outcomes including vessel formation and the onset of cancer.
Advances in experimental medicine and biology 01/2012; 727:1-14. · 1.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: There is increasing evidence that phloroglucinol, a compound from Ecklonia cava, induces the apoptosis of cancer cells, eventually suppressing tumor angiogenesis.
This is the first report on phloroglucinol's ability to potentially inhibit the functional bioactivities of endothelial progenitor cells (EPCs) and thereby attenuate tumor growth and angiogenesis in the Lewis lung carcinoma (LLC)-tumor-bearing mouse model. Although Phloroglucinol did not affect their cell toxicity, it specifically inhibited vascular endothelial growth factor (VEGF) dependent migration and capillary-like tube formation of EPCs. Our matrigel plug assay clearly indicated that orally injected phloroglucinol effectively disrupts VEGF-induced neovessel formation. Moreover, we demonstrated that when phloroglucinol is orally administered, it significantly inhibits tumor growth and angiogenesis as well as CD45(-)/CD34(+) progenitor mobilization into peripheral blood in vivo in the LLC-tumor-bearing mouse model.
These results suggest a novel role for Phloroglucinol: Phloroglucinol might be a modulator of circulating EPC bioactivities, eventually suppressing tumorigenesis. Therefore, phloroglucinol might be a candidate compound for biosafe drugs that target tumor angiogenesis.
PLoS ONE 01/2012; 7(4):e33618. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A number of studies have revealed that stress signaling and subsequent stress responses in stem/progenitor cells are responsible for attenuated regeneration or degenerative disease. Because ionizing radiation (IR), which sensitizes diverse types of stem cells, reportedly induces cardio-circulatory diseases, we hypothesized that IR-induced vascular abnormalities are associated with defects in endothelial progenitor cells (EPCs) that are responsible for vascular homeostasis.
We used an irradiated mouse model to mimic the IR effect on vasculogenesis. Mouse EPCs isolated from irradiated mice and human EPCs exposed to IR were used for functional analysis and gene expression study. Under IR exposure, EPCs were depleted, and their function for vasculogenesis in vitro and in vivo was significantly reduced. In such IR-mediated stress responses, upregulating p21Cip1 and downregulating vascular endothelial growth factor (VEGF) were mediated by p53 transcriptional activity.
The results of the present study suggest that suppression of p53 would be clinically applicable to (1) minimize the functional defects in EPCs in order to prevent the onset of vascular diseases caused by radiation therapy or radiation exposure and also to (2) provide novel insight into the mechanisms of IR-induced vascular damage and a possible strategy to minimize vascular damage by IR.
Arteriosclerosis Thrombosis and Vascular Biology 11/2011; 32(2):343-52. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although endothelial progenitor cells (EPCs) differentiate from minor populations of stem cells in bone marrow (BM), the differential role of hematopoietic stem cell (HSC) subpopulations in EPC development is largely unclear. Morphological characterization of EPC colonies has revealed that c-kit+/Sca-1+/lineage (Lin)-(KSL) cells mainly develop small EPC-colony forming units (CFUs) not large EPC-CFUs. In contrast, c-kit+/Sca-1-/Lin- (KL) cells develop large EPC-CFUs not small EPC-CFUs. Neither c-kit-/Sca-1+/Lin- (SL) cells nor c-kit-/Sca-1-/Lin- (L) cells develop EPC-CFUs to an appreciable extent. Hindlimb ischemia enhances formation of large EPC-CFUs from all HSC subpopulations, suggesting an important role for ischemia in functional EPC development. Real time RT-PCR analysis shows that KSL, KL and SL cells but not L cells express various factors at high levels, maintaining a BM-EPC pool. In hindlimb ischemia, transplanted KSL, KL and SL cells efficiently differentiate into endothelial lineage cells in situ and augment capillary density. The percentage of Ki-67+ cycling cells among transplanted cells in ischemic tissue was also greater for KSL, KL and SL cells than L cells. Moreover, the frequency of VEGF- or SDF-1-expressing cells was higher transplanted KSL, KL or SL cells than L cells. Thus, KSL, KL and SL cells are not different in their angiogenic competence under ischemic conditions. In conclusion, although KSL cells are clearly the most potent contributors to EPC development, KL and SL cells may also contribute to neovascularization via both autocrine and paracrine mechanisms in response to ischemic signals.
Journal of Molecular and Cellular Cardiology 04/2011; 51(3):308-17. · 5.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Endothelial progenitor cells (EPCs) were shown to have angiogenic potential contributing to neovascularization. However, a clear definition of mouse EPCs by cell surface markers still remains elusive. We hypothesized that CD34 could be used for identification and isolation of functional EPCs from mouse bone marrow.
CD34(+) cells, c-Kit(+)/Sca-1(+)/Lin(-) (KSL) cells, c-Kit(+)/Lin(-) (KL) cells and Sca-1(+)/Lin(-) (SL) cells were isolated from mouse bone marrow mononuclear cells (BMMNCs) using fluorescent activated cell sorting. EPC colony forming capacity and differentiation capacity into endothelial lineage were examined in the cells. Although CD34(+) cells showed the lowest EPC colony forming activity, CD34(+) cells exhibited under endothelial culture conditions a more adherent phenotype compared with the others, demonstrating the highest mRNA expression levels of endothelial markers vWF, VE-cadherin, and Flk-1. Furthermore, a dramatic increase in immediate recruitment of cells to the myocardium following myocardial infarction and systemic cell injection was observed for CD34(+) cells comparing with others, which could be explained by the highest mRNA expression levels of key homing-related molecules Integrin β2 and CXCR4 in CD34(+) cells. Cell retention and incorporation into the vasculature of the ischemic myocardium was also markedly increased in the CD34(+) cell-injected group, giving a possible explanation for significant reduction in fibrosis area, significant increase in neovascularization and the best cardiac functional recovery in this group in comparison with the others.
These findings suggest that mouse CD34(+) cells may represent a functional EPC population in bone marrow, which could benefit the investigation of therapeutic EPC biology.
PLoS ONE 01/2011; 6(5):e20219. · 4.09 Impact Factor
-
Tomoyuki Matsumoto,
Masaaki Ii,
Hiromi Nishimura,
Taro Shoji,
Yutaka Mifune,
Atsuhiko Kawamoto,
Ryosuke Kuroda,
Tomoaki Fukui,
Yohei Kawakami,
Tomoya Kuroda, Sang Mo Kwon,
Hiroto Iwasaki,
Miki Horii,
Ayumi Yokoyama,
Akira Oyamada,
Sang Yang Lee,
Shinya Hayashi,
Masahiro Kurosaka,
Satoshi Takaki,
Takayuki Asahara
[show abstract]
[hide abstract]
ABSTRACT: The therapeutic potential of hematopoietic stem cells/endothelial progenitor cells (HSCs/EPCs) for fracture healing has been demonstrated with evidence for enhanced vasculogenesis/angiogenesis and osteogenesis at the site of fracture. The adaptor protein Lnk has recently been identified as an essential inhibitor of stem cell factor (SCF)-cKit signaling during stem cell self-renewal, and Lnk-deficient mice demonstrate enhanced hematopoietic reconstitution. In this study, we investigated whether the loss of Lnk signaling enhances the regenerative response during fracture healing. Radiological and histological examination showed accelerated fracture healing and remodeling in Lnk-deficient mice compared with wild-type mice. Molecular, physiological, and morphological approaches showed that vasculogenesis/angiogenesis and osteogenesis were promoted in Lnk-deficient mice by the mobilization and recruitment of HSCs/EPCs via activation of the SCF-cKit signaling pathway in the perifracture zone, which established a favorable environment for bone healing and remodeling. In addition, osteoblasts (OBs) from Lnk-deficient mice had a greater potential for terminal differentiation in response to SCF-cKit signaling in vitro. These findings suggest that inhibition of Lnk may have therapeutic potential by promoting an environment conducive to vasculogenesis/angiogenesis and osteogenesis and by facilitating OB terminal differentiation, leading to enhanced fracture healing.
Journal of Experimental Medicine 09/2010; 207(10):2207-23. · 13.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Adipose tissue is one of the promising sources of multipotent stem cells in human. Human multipotent adipose-derived stem (hMADS) cells have recently been isolated and showed differentiation potential into multiple mesenchymal lineages in vitro and in vivo. On the basis of these evidences, we examined the therapeutic efficacy of hMADS cells for fracture healing in an immunodeficient rat femur non-union fracture model. Local transplantation of hMADS cells radiographically and histologically promoted fracture healing with significant improvement of biomechanical function at the fracture sites compared with local transplantation of human fibroblasts (hFB) or PBS administration. Histological capillary density and physiological blood flow by laser Doppler perfusion imaging were significantly greater in hMADS group than hFB and PBS groups. Expressions of intrinsic (rat) bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF) and angiopoietin-1 in peri-fracture tissue were upregulated in hMADS group than other groups. In addition, presence of BMP-2 or VEGF activated the proliferation and migration of hMADS cells in vitro. These results indicate that hMADS cells stimulate the interaction between the transplanted cells and the resident cells stronger than other cells, and they promote fracture healing more effectively. Furthermore, immunohistochemistry for human-specific antibodies revealed direct differentiation of hMADS cells into osteoblasts or endothelial cells in newly formed callus or vasculature, respectively. RT-PCR for human-specific primers for osteogenic/endothelial markers also disclosed osteogenic and vasculogenic plasticity of the transplanted hMADS cells at the early stage of fracture healing. The present results suggest that transplantation of hMADS cells may become a useful strategy for cell-based bone regeneration in the future clinical setting.
Laboratory Investigation 02/2010; 90(4):637-49. · 3.64 Impact Factor
-
Naosuke Kamei, Sang-Mo Kwon,
Cantas Alev,
Masakazu Ishikawa,
Ayumi Yokoyama,
Kazuyoshi Nakanishi,
Kiyotaka Yamada,
Miki Horii,
Hiromi Nishimura,
Satoshi Takaki,
Atsuhiko Kawamoto,
Masaaki Ii,
Hiroshi Akimaru,
Nobuhiro Tanaka,
Shin-Ichi Nishikawa,
Mitsuo Ochi,
Takayuki Asahara
[show abstract]
[hide abstract]
ABSTRACT: Lnk is an intracellular adaptor protein reported as a negative regulator of proliferation in c-Kit positive, Sca-1 positive, lineage marker-negative (KSL) bone marrow cells. The KSL fraction in mouse bone marrow is believed to represent a population of hematopoietic and endothelial progenitor cells (EPCs). We report here that, in vitro, Lnk(-/-) KSL cells form more EPC colonies than Lnk(+/+) KSL cells and show higher expression levels of endothelial marker genes, including CD105, CD144, Tie-1, and Tie2, than their wild-type counterparts. In vivo, the administration of Lnk(+/+) KSL cells to a mouse spinal cord injury model promoted angiogenesis, astrogliosis, axon growth, and functional recovery following injury, with Lnk(-/-) KSL being significantly more effective in inducing and promoting these regenerative events. At day 3 following injury, large vessels could be observed in spinal cords treated with KSL cells, and reactive astrocytes were found to have migrated along these large vessels. We could further show that the enhancement of astrogliosis appears to be caused in conjunction with the acceleration of angiogenesis. These findings suggest that Lnk deletion reinforces the commitment of KSL cells to EPCs, promoting subsequent repair of injured spinal cord through the acceleration of angiogenesis and astrogliosis.
Stem Cells 10/2009; 28(2):365-75. · 7.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: It is generally accepted that endothelial progenitor cells (EPCs) can promote postnatal neovascularization and be used for vascular regeneration, thus representing a promising new tool for the treatment of cardiovascular diseases. However, the exact molecular mechanisms and signaling pathways regulating the proliferation, differentiation, and migration of EPCs; their interaction with niche cells; and their regenerative capacity still remain elusive. The Notch signaling pathway shown to be important for the maintenance and differentiation of various stem and progenitor populations is also involved in EPC regulation. In this review, we will summarize the current knowledge about the pivotal role of Notch signaling in EPC biology and EPC-mediated vascular regeneration.
Trends in cardiovascular medicine 07/2009; 19(5):170-3. · 4.37 Impact Factor
-
Sang-Mo Kwon,
Takahiro Suzuki,
Atsuhiko Kawamoto,
Masaaki Ii,
Masamichi Eguchi,
Hiroshi Akimaru,
Mika Wada,
Tomoyuki Matsumoto,
Haruchika Masuda,
Yoshihiro Nakagawa,
Hiromi Nishimura,
Kenji Kawai,
Satoshi Takaki,
Takayuki Asahara
[show abstract]
[hide abstract]
ABSTRACT: Despite the fact that endothelial progenitor cells (EPCs) are important for postnatal neovascularization, their origins, differentiation, and modulators are not clear. Here, we demonstrate that Lnk, a negative regulator of hematopoietic stem cell proliferation, controls endothelial commitment of c-kit(+)/Sca-1(+)/Lineage(-) (KSL) subpopulations of bone marrow cells. The results of EPC colony-forming assays reveal that small (primitive) EPC colony formation by CD34(-) KSLs and large (definitive) EPC colony formation by CD34((dim)) KSLs are more robust in lnk(-/-) mice. In hindlimb ischemia, perfusion recovery is augmented in lnk(-/-) mice through enhanced proliferation and mobilization of EPCs via c-Kit/stem cell factor. We found that Lnk-deficient EPCs are more potent actors than resident cells in hindlimb perfusion recovery and ischemic neovascularization, mainly via the activity of bone marrow-EPCs. Similarly, lnk(-/-) mice show augmented retinal neovascularization and astrocyte network maturation without an increase in indicators of pathogenic angiogenesis in an in vivo model of retinopathy. Taken together, our results provide strong evidence that Lnk regulates bone marrow-EPC kinetics in vascular regeneration. Selective targeting of Lnk may be a safe and effective strategy to augment therapeutic neovascularization by EPC transplantation.
Circulation Research 04/2009; 104(8):969-77. · 9.49 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Despite accumulating evidence that proves the pivotal role of endothelial progenitor cells (EPCs) in ischemic neovascularization, the key signaling cascade that regulates functional EPC kinetics remains unclear.
In this report, we show that inactivation of specific Jagged-1 (Jag-1)-mediated Notch signals leads to inhibition of postnatal vasculogenesis in hindlimb ischemia via impairment of proliferation, survival, differentiation, and mobilization of bone marrow-derived EPCs. Bone marrow-derived EPCs obtained from Jag-1-/- mice, but not Delta-like (Dll)-1-/- mice, demonstrated less therapeutic potential for ischemic neovascularization than EPCs from the wild type. In contrast, a gain-of-function study using 3T3 stromal cells overexpressing Notch ligand revealed that Jag-1-mediated Notch signals promoted EPC commitment, which resulted in enhanced neovascularization. The impaired neovascularization in Jag-1-/- mice was profoundly rescued by transplantation of Jag-1-stimulated EPCs.
These data indicate that specific Jag-1-derived Notch signals from the bone marrow microenvironment are critical for EPC-mediated vasculogenesis, thus providing an important clue for modulation of strategies for therapeutic neovascularization.
Circulation 08/2008; 118(2):157-65. · 14.74 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We recently reported that i.v. transplantation of adult human circulating CD34+ cells, an endothelial/hematopoietic progenitor-enriched cell population, contributes to fracture healing through the enhancement of vasculogenesis and osteogenesis. However, the scarcity of CD34+ cells in the adult human is a critical issue for the future clinical application of this method. To overcome this issue, we assessed in vitro and in vivo capacity of granulocyte colony-stimulating factor-mobilized peripheral blood (GM-PB) human CD34+ cells for vasculogenesis and osteogenesis. First, we confirmed the differentiation capability of GM-PB CD34+ cells into osteoblasts in vitro. Second, local transplantation of GM-PB CD34+ cells on atelocollagen scaffold was performed in nude rats in a model of unhealing fractures. Immunostaining for human leukocyte antigen-ABC of tissue samples 1 week after fracture and cell therapy showed the superior incorporation after local transplantation compared with systemic infusion. Third, the effects of local transplantation of 10(5) (Hi), 10(4) (Mid), or 10(3) (Lo) doses of GM-PB CD34+ cells or phosphate-buffered saline (PBS) on fracture healing were compared. Extrinsic vasculogenic and osteogenic differentiation of GM-PB CD34+ cells, enhancement of the intrinsic angio-osteogenesis by recipient cells, augmentation of blood flow recovery at the fracture sites, and radiological and histological confirmation of fracture healing were observed only in the Hi and Mid groups but not in the Lo and PBS groups. These results strongly suggest that local transplantation of GM-PB CD34+ cells with atelocollagen scaffold is a feasible strategy for therapeutic vasculogenesis and osteogenesis needed for fracture healing. Disclosure of potential conflicts of interest is found at the end of this article.
Stem Cells 07/2008; 26(6):1395-405. · 7.78 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Endothelial progenitor cells play an important role in neovascularization of ischemic flaps, a process that is significantly impaired in diabetes. This is the first investigation into the effects of flap ischemia on circulating and bone marrow-derived endothelial progenitor cells. Potential mechanisms for impaired vasculogenesis in diabetes are also investigated.
Circulating and bone marrow-derived endothelial progenitor cells were isolated from wild-type (n = 24) and diabetic mice (n = 24) with ischemic flaps (days 0, 1, 3, and 7). The number and vasculogenic function of primitive and definitive endothelial progenitor cells were determined by fluorescence-activated cell sorting analysis, culture assay, and vasculogenic colony-forming assay.
Ischemia mobilized endothelial progenitor cells (25 +/- 0.5 cells per high-power field at day 7 versus 9.0 +/- 0.6 cells per high-power field, p < 0.01) and enhanced the vasculogenic potential of circulating primitive endothelial progenitor cells (23 +/- 3.2 at day 3 versus 14 +/- 0.8, p < 0.01) relative to baseline. In the bone marrow, endothelial progenitor cell number and vasculogenic potential peaked at day 3 (2.1 +/- 0.3 x 10(5) cells versus 1.3 +/- 0.1 x 10(5) cells, p < 0.05; 36 +/- 1.9 versus 27 +/- 1.6, p < 0.05, respectively). In diabetes, circulating endothelial progenitor cell mobilization (5.8 +/- 0.4 cells per high-power field versus 9.0 +/- 0.6 cells per high-power field, p < 0.01) and vasculogenic potential (36 +/- 1.7 versus 43 +/- 2.6, p < 0.05) were impaired relative to the wild-type animals. Bone marrow-derived endothelial progenitor cell number was normal in diabetic animals, but the vasculogenic potential of these cells was significantly impaired (5.7 +/- 0.8 day 1 versus 13.4 +/- 2.5, p < 0.05).
Flap ischemia induces phenotypic changes in bone marrow-derived endothelial progenitor cells that subsequently traffic through the circulation. The vasculogenic potential of endothelial progenitor cells at various stages of differentiation is impaired in diabetes and thus may account for impaired ischemia-induced vasculogenesis observed clinically.
Plastic and reconstructive surgery 06/2008; 121(6):1929-42. · 2.74 Impact Factor
