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General Comment |
binds CXCL12../////Targeting of the pulmonary capillary vascular niche promotes lung alveolar repair and ameliorates fibrosis. Cao Z et al. (2016) Although the lung can undergo self-repair after injury, fibrosis in chronically injured or diseased lungs can occur at the expense of regeneration. Here we study how a hematopoietic-vascular niche regulates alveolar repair and lung fibrosis. Using intratracheal injection of bleomycin or hydrochloric acid in mice, we show that repetitive lung injury activates pulmonary capillary endothelial cells (PCECs) and perivascular macrophages, impeding alveolar repair and promoting fibrosis. Whereas the chemokine receptor CXCR7, expressed on PCECs, acts to prevent epithelial damage and ameliorate fibrosis after a single round of treatment with bleomycin or hydrochloric acid, repeated injury leads to suppression of CXCR7 expression and recruitment of vascular endothelial growth factor receptor 1 (VEGFR1)-expressing perivascular macrophages. This recruitment stimulates Wnt/β-catenin-dependent persistent upregulation of the Notch ligand Jagged1 (encoded by Jag1) in PCECs, which in turn stimulates exuberant Notch signaling in perivascular fibroblasts and enhances fibrosis. Administration of a CXCR7 agonist or PCEC-targeted Jag1 shRNA after lung injury promotes alveolar repair and reduces fibrosis. Thus, targeting of a maladapted hematopoietic-vascular niche, in which macrophages, PCECs and perivascular fibroblasts interact, may help to develop therapy to spur lung regeneration and alleviate fibrosis.//////////////////
NCBI Summary:
This gene encodes a member of the G-protein coupled receptor family. Although this protein was earlier thought to be a receptor for vasoactive intestinal peptide (VIP), it is now considered to be an orphan receptor, in that its endogenous ligand has not been identified. The protein is also a coreceptor for human immunodeficiency viruses (HIV). Translocations involving this gene and HMGA2 on chromosome 12 have been observed in lipomas. [provided by RefSeq, Jul 2008]
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