Rescue of defective branching nephrogenesis in renal-coloboma syndrome by the caspase inhibitor, Z-VAD-fink
Rescue of defective branching nephrogenesis in renal-coloboma syndrome by the caspase inhibitor, Z-VAD-fink
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DOI：
10.1097/01.asn.0000111248.23454.19
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发表时间：
2004-02-01
影响因子：
13.6
通讯作者：
Goodyer, P
中科院分区：
文献类型：
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作者：
Clark, P;Dziarmaga, A;Goodyer, P
在肾缺损综合征(RCS)中，PAX2基因的零突变由于先天性肾单位缺陷而导致肾脏发育不全；受影响的个体可能在儿童时期发展为肾功能不全。在正常的肾脏发育过程中，PAX2在整个树枝状输尿管芽(UB)中高水平表达；最近的观察表明，它的关键作用之一是抑制集合管谱系中的细胞凋亡。作者推测，由于PAX2单倍体功能不全导致的UB细胞凋亡率的增加，必然会直接影响发育中的肾脏的分支形态形成率和出生前形成的肾单位的数量，当人类肾脏发育结束时。如果是这样的话，作者推测caspase抑制剂可能被用来抑制Pax2(1Neu)突变小鼠肾脏发育过程中不想要的Ub细胞的凋亡，并挽救遗传的Ub分支缺陷。与野生型相比，Pax2(1Neu)突变小鼠E17.5肾的纵向横截面积较小(-25%)，集合管细胞凋亡率增加3.5倍；体外树枝生长50h的突变型E13.5肾外植体的末端分支比野生型少18%。然而，暴露于caspase抑制剂Z-VAD-fmk(25um)时，突变外植体的末端分枝数显著增加(23%)。它还增加了野生型外植体的分枝，明显反映了Z-VAD-fmk对体外培养条件诱导的基础细胞凋亡的影响。同样，当孕鼠每天注射Z-VAD-fmk(10µg/g体重，从E10.5到E17.5)时，Pax2(1Neu)胎儿集合管细胞的凋亡率被抑制到未处理突变体的40%，到E14，末梢分枝数增加到未处理突变体的152%。这些研究支持这样的假设，即PAX2通常通过抑制UB细胞凋亡来优化胎儿肾脏的分支形态发生速率。此外，这表明caspase抑制剂可以挽救PAX2突变引起的分支缺陷。
In renal-coloboma syndrome (RCS), null mutations of the PAX2 gene cause renal hypoplasia due to a congenital deficit of nephrons; affected individuals may develop renal insufficiency in childhood. During normal kidney development, PAX2, is expressed at high levels throughout the arborizing ureteric bud (UB); recent observations suggest that one of its key roles is to suppress apoptosis in this collecting duct lineage. The authors hypothesized that increased UB cell apoptosis due to PAX2 haploinsufficiency must directly influence the rate of branching morphogenesis in developing kidney and the number of nephrons that can be formed before birth, when nephrogenesis in humans comes to an end. If so, the authors reasoned that caspase inhibitors might be used to suppress unwanted UB cell apoptosis during kidney development in Pax2(1Neu) mutant mice and rescue the genetic UB branching defect. E17.5 kidneys from Pax2(1Neu) mutant mice had smaller (-25%) longitudinal cross-sectional area and 3.5-fold increase in collecting duct cell apoptosis versus wild-type littermates; mutant E13.5 kidney explants allowed to arborize for 50 h in vitro had 18% fewer terminal branches than wild-types. However, exposure to the caspase inhibitor, Z-VAD-fmk (25 muM), significantly increased terminal branch number in mutant explants (23%). It also increased branching in wild-type explants, apparently reflecting an effect of Z-VAD-fmk on basal apoptosis induced by ex vivo culture conditions. Similarly, when pregnant mice were injected daily with Z-VAD-fmk (10 mug/g weight from E10.5 to E17.5), apoptosis of Pax2(1Neu) fetal collecting duct cells was suppressed to 40% of untreated mutants; by E14, terminal branch number was increased to 152% that of untreated litters. These studies support the hypothesis that PAX2 normally optimizes the rate of branching morphogenesis in fetal kidney by suppressing UB apoptosis. Furthermore, it suggests that caspase inhibitors can rescue the branching defect caused by PAX2 mutations.