Cellular mechanisms of regenerative effects of granulocyte colony-stimulating factor (G-CSF) in hindlimb ischemia

重组粒细胞集落刺激因子（rG-CSF）可减轻心、脑、肢体缺血的功能性后果。rG-CSF介导的骨髓来源的细胞动员，导致它们在缺血组织中的归巢增加，在那里它们可以通过旁分泌机制起作用，可能是这种作用的基础。此外，rG-CSF可在缺血组织中发挥直接作用，因为其受体（G-CSFR）表达于包括血管细胞在内的各种常驻细胞类型上。然而，虽然rG-CSF的治疗效果是无可争议的，但内源性G-CSF在缺血性疾病中的自主再生中的作用是神秘的。因此，本项目将揭示内源性G-CSF对使用G-CSF和G-CSFR敲除小鼠的小鼠后肢缺血模型中的代偿性血管生长的影响。为了检查这些小鼠中G-SCF信号传导缺陷的功能后果，将应用激光多普勒灌注成像（LDPI）和核磁共振成像（NMRI）。内源性G-CSF的潜在作用机制可能是目前讨论的机制，但尚未明确探索rG-CSF的作用（见上文）。因此，几种类型的转基因，骨髓嵌合小鼠将被用来揭示可能的作用机制的内源性G-CSF和外源性rGCSF的平行。这些研究将包括骨髓细胞依赖性和非依赖性G-CSF效应在代偿性血管生长中的相对贡献分析。应研究可能导致这些效应的细胞活动，如增殖、分化和凋亡。

Recombinant granulocyte colony-stimulating factor (rG-CSF) relieves the functional consequencesof ischemia in heart, brain and limbs. rG-CSF-mediated mobilization of bone marrow-derived cells,leading to their increased homing in the ischemic tissue where they could act by paracrinemechanisms, may underly this effect. In addition or alternatively, rG-CSF may exert direct effects inthe ischemic tissue as its receptor (G-CSFR) is expressed on various resident cell types including vascular cells. However, while therapeutic effects of rG-CSF are indisputable the role of endogeneous G-CSF in autonomous regeneration in ischemic diseases is enigmatic. Therefore, the present project shall reveal the impact of endogeneous G-CSF for compensatory vessel growth in a murine hindlimb ischemia model using G-CSF- and G-CSFR knockout mice. To examine the functional consequences of deficient G-SCF signalling in these mice Laser Doppier Perfusion Imaging (LDPI) and Nuclear Magnetic Resonance Imaging (NMRI) will be applied. The mechanisms of potential effects of endogeneous G-CSF may be those currently discussed, but not definitively explored for rG-CSF effects (see above). Therefore, several types of transgenic, bone marrow-chimeric mice will be used to reveal possible mechanisms of action of endogeneous G-CSF and exogeneous rGCSF in parallel. These investigations will comprise the analysis of the relative contributions of bone marrow cell-dependent and -independent G-CSF effects in compensatory vessel growth. Cellular activities, such as proliferation, differentiation and apoptosis potentially contributing to these effects shall be investigated.