White Rebecca L, Nash Gerard, Kavanagh Dean P J, Savage Caroline O S, Kalia Neena
School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.
PLoS One. 2013 Jun 19;8(6):e66489. doi: 10.1371/journal.pone.0066489. Print 2013.
Renal disease affects over 500 million people worldwide and is set to increase as treatment options are predominately supportive. Evidence suggests that exogenous haematopoietic stem cells (HSCs) can be of benefit but due to the rarity and poor homing of these cells, benefits are either minor or transitory. Mechanisms governing HSC recruitment to injured renal microcirculation are poorly understood; therefore this study determined (i) the adhesion molecules responsible for HSC recruitment to the injured kidney, (ii) if cytokine HSC pre-treatment can enhance their homing and (iii) the molecular mechanisms accountable for any enhancement.
Adherent and free-flowing HSCs were determined in an intravital murine model of renal ischaemia-reperfusion injury. Some HSCs and animals were pre-treated prior to HSC infusion with function blocking antibodies, hyaluronidase or cytokines. Changes in surface expression and clustering of HSC adhesion molecules were determined using flow cytometry and confocal microscopy. HSC adhesion to endothelial counter-ligands (VCAM-1, hyaluronan) was determined using static adhesion assays in vitro.
CD49d, CD44, VCAM-1 and hyaluronan governed HSC adhesion to the IR-injured kidney. Both KC and SDF-1α pre-treatment strategies significantly increased HSC adhesion within injured kidney, whilst SDF-1α also increased numbers continuing to circulate. SDF-1α and KC did not increase CD49d or CD44 expression but increased HSC adhesion to VCAM-1 and hyaluronan respectively. SDF-1α increased CD49d surface clustering, as well as HSC deformability.
Increasing HSC adhesive capacity for its endothelial counter-ligands, potentially through surface clustering, may explain their enhanced renal retention in vivo. Furthermore, increasing HSC deformability through SDF-1α treatment could explain the prolonged systemic circulation; the HSC can therefore continue to survey the damaged tissue instead of becoming entrapped within non-injured sites. Therefore manipulating these mechanisms of HSC recruitment outlined may improve the clinical outcome of cellular therapies for kidney disease.
肾脏疾病影响着全球超过5亿人，并且随着治疗方案主要为支持性治疗，其发病率还将上升。有证据表明外源性造血干细胞（HSC）可能有益，但由于这些细胞稀少且归巢能力差，其益处要么微小，要么短暂。目前对调控HSC募集至受损肾脏微循环的机制了解甚少；因此，本研究确定了（i）负责HSC募集至受损肾脏的黏附分子，（ii）细胞因子预处理HSC是否能增强其归巢能力，以及（iii）导致任何增强作用的分子机制。
在肾缺血再灌注损伤的活体小鼠模型中测定贴壁和自由流动的HSC。在输注HSC之前，一些HSC和动物用功能阻断抗体、透明质酸酶或细胞因子进行预处理。使用流式细胞术和共聚焦显微镜测定HSC黏附分子的表面表达和聚集变化。使用体外静态黏附试验测定HSC与内皮细胞反配体（VCAM-1、透明质酸）的黏附。
CD49d、CD44、VCAM-1和透明质酸调控HSC与缺血再灌注损伤肾脏的黏附。KC和SDF-1α预处理策略均显著增加了受损肾脏内的HSC黏附，而SDF-1α还增加了继续循环的细胞数量。SDF-1α和KC未增加CD49d或CD44表达，但分别增加了HSC与VCAM-1和透明质酸的黏附。SDF-1α增加了CD49d表面聚集以及HSC的变形能力。
潜在地通过表面聚集增加HSC对其内皮细胞反配体的黏附能力，可能解释了它们在体内增强的肾脏滞留。此外，通过SDF-α治疗增加HSC变形能力可以解释其延长的全身循环；因此，HSC可以继续监测受损组织，而不是被困在未受损部位。因此，操纵上述HSC募集机制可能会改善肾脏疾病细胞治疗的临床结果。
