23 research outputs found

    Essential but differential role for CXCR4 and CXCR7 in the therapeutic homingof human renal progenitor cells

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    Recently, we have identified a population of renal progenitor cells in human kidneys showing regenerative potential for injured renal tissue of SCID mice. We demonstrate here that among all known chemokine receptors, human renal progenitor cells exhibit high expression of both stromal-derived factor-1 (SDF-1) receptors, CXCR4 and CXCR7. In SCID mice with acute renal failure (ARF), SDF-1 was strongly up-regulated in resident cells surrounding necrotic areas. In the same mice, intravenously injected renal stem/progenitor cells engrafted into injured renal tissue decreased the severity of ARF and prevented renal fibrosis. These beneficial effects were abolished by blocking either CXCR4 or CXCR7, which dramatically reduced the number of engrafting renal progenitor cells. However, although SDF-1–induced migration of renal progenitor cells was only abolished by an anti-CXCR4 antibody, transendothelial migration required the activity of both CXCR4 and CXCR7, with CXCR7 being essential for renal progenitor cell adhesion to endothelial cells. Moreover, CXCR7 but not CXCR4 was responsible for the SDF-1–induced renal progenitor cell survival. Collectively, these findings suggest that CXCR4 and CXCR7 play an essential, but differential, role in the therapeutic homing of human renal progenitor cells in ARF, with important implications for the development of stem cell–based therapies

    Sequence-dependent attack on peptides by photoactivated platinum anticancer complexes

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    Octahedral platinum(IV) complexes such as trans,trans,trans-[Pt(N3)2(OH)2(pyridine)2] (1) are stable in the dark, but potently cytotoxic to a range of cancer cells when activated by UVA or visible light, and active in vivo. Photoactivation causes the reduction of the complex and leads to the formation of unusual Pt(II) lesions on DNA. However, radicals are also generated in the excited state resulting from photoactivation (J. S. Butler, J. A. Woods, N. J. Farrer, M. E. Newton and P. J. Sadler, J. Am. Chem. Soc., 2012, 134, 16508–16511). Here we show that once photoactivated, 1 also can interact with peptides, and therefore proteins are potential targets of this candidate drug. High resolution FT-ICR MS studies show that reactions of 1 activated by visible light with two neuropeptides Substance P, RPKPQQFFGLM-NH2 (SubP) and [Lys]3-Bombesin, pEQKLGNQWAVGHLM-NH2 (K3-Bom) give rise to unexpected products, in the form of both oxidised and platinated peptides. Further MS/MS analysis using electron-capture dissociation (ECD) dissociation pathways (enabling retention of the Pt complex during fragmentation), and EPR experiments using the spin-trap DEPMPO, show that the products generated during the photoactivation of 1 depend on the amino acid composition of the peptide. This work reveals the multitargeting nature of excited state platinum anticancer complexes. Not only can they target DNA, but also peptides (and proteins) by sequence dependent platination and radical mechanisms

    Regeneration of Glomerular Podocytes by Human Renal Progenitors

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    Depletion of podocytes, common to glomerular diseases in general, plays a role in the pathogenesis of glomerulosclerosis. Whether podocyte injury in adulthood can be repaired has not been established. Here, we demonstrate that in the adult human kidney, CD133+CD24+ cells consist of a hierarchical population of progenitors that are arranged in a precise sequence within Bowman's capsule and exhibit heterogeneous potential for differentiation and regeneration. Cells localized to the urinary pole that expressed CD133 and CD24, but not podocyte markers (CD133+CD24+PDX− cells), could regenerate both tubular cells and podocytes. In contrast, cells localized between the urinary pole and vascular pole that expressed both progenitor and podocytes markers (CD133+CD24+PDX+) could regenerate only podocytes. Finally, cells localized to the vascular pole did not exhibit progenitor markers, but displayed phenotypic features of differentiated podocytes (CD133−CD24−PDX+ cells). Injection of CD133+CD24+PDX− cells, but not CD133+CD24+PDX+ or CD133-CD24− cells, into mice with adriamycin-induced nephropathy reduced proteinuria and improved chronic glomerular damage, suggesting that CD133+CD24+PDX− cells could potentially treat glomerular disorders characterized by podocyte injury, proteinuria, and progressive glomerulosclerosis

    Regenerative Potential of Embryonic Renal Multipotent Progenitors in Acute Renal Failure

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    Bone marrow- and adult kidney-derived stem/progenitor cells hold promise in the development of therapies for renal failure. Here is reported the identification and characterization of renal multipotent progenitors in human embryonic kidneys that share CD24 and CD133 surface expression with adult renal progenitors and have the capacity for self-renewal and multilineage differentiation. It was found that these CD24+CD133+ cells constitute the early primordial nephron but progressively disappear during nephron development until they become selectively localized to the urinary pole of Bowman's capsule. When isolated and injected into SCID mice with acute renal failure from glycerol-induced rhabdomyolysis, these cells regenerated different portions of the nephron, reduced tissue necrosis and fibrosis, and significantly improved renal function. No tumorigenic potential was observed. It is concluded that CD24+CD133+ cells represent a subset of multipotent embryonic progenitors that persist in human kidneys from early stages of nephrogenesis. The ability of these cells to repair renal damage, together with their apparent lack of tumorigenicity, suggests their potential in the treatment of renal failure. Copyright © 2007 by the American Society of Nephrology

    Regenerative potential of embryonic renal multipotent progenitors in acute renal failure

    No full text
    Bone marrow- and adult kidney-derived stem/progenitor cells hold promise in the development of therapies for renal failure. Here is reported the identification and characterization of renal multipotent progenitors in human embryonic kidneys that share CD24 and CD133 surface expression with adult renal progenitors and have the capacity for self-renewal and multilineage differentiation. It was found that these CD24+CD133+ cells constitute the early primordial nephron but progressively disappear during nephron development until they become selectively localized to the urinary pole of Bowman's capsule. When isolated and injected into SCID mice with acute renal failure from glycerol-induced rhabdomyolysis, these cells regenerated different portions of the nephron, reduced tissue necrosis and fibrosis, and significantly improved renal function. No tumorigenic potential was observed. It is concluded that CD24+CD133+ cells represent a subset of multipotent embryonic progenitors that persist in human kidneys from early stages of nephrogenesis. The ability of these cells to repair renal damage, together with their apparent lack of tumorigenicity, suggests their potential in the treatment of renal failure. Copyright © 2007 by the American Society of Nephrology
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