Spatiotemporal expression and transcriptional regulation of heme oxygenase and biliverdin reductase genes in zebrafish (Danio rerio) suggest novel roles during early developmental periods of heightened oxidative stress.
Spatiotemporal expression and transcriptional regulation of heme oxygenase and biliverdin reductase genes in zebrafish (Danio rerio) suggest novel roles during early developmental periods of heightened oxidative stress.
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DOI：
10.1016/j.cbpc.2016.10.006
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发表时间：
2017-01
期刊：
影响因子：
--
通讯作者：
Jenny MJ
中科院分区：
文献类型：
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作者：
Holowiecki A;O'Shields B;Jenny MJ
血红素加氧酶1(Hmox1)将血红素降解为胆绿素，胆绿素还原酶(BVRa或BVRb)以类似于经典抗氧化剂谷胱甘肽循环途径的方式将胆绿素转化为胆红素。为了更好地了解BVR酶在斑马鱼发育过程中可能发挥的潜在抗氧化作用，我们研究了斑马鱼hmox1a、bvrA和bvrb在基础条件下和在促氧化剂暴露下的时空表达和转录调控。所有这三个基因在发育过程中都表现出与经典造血祖细胞一致的时空表达模式。瞬时敲除Nrf2a基因不会削弱ISH检测bvra或bvrb的能力，也不会改变对镉暴露的空间表达模式。虽然hmox1a：mCherry荧光在中间细胞团(原始红细胞分化的瞬时位置)中被发现，但在Nrf2a变异体中的表达并未完全减弱，但实时RT-PCR显示hmox1a的表达显著减少。此外，GATA-1基因敲除并没有减弱hmox1a：mCherry的荧光。然而，虽然在24 HPF时，ISH完全检测不到bvrb的表达，但在GATA-1变异体中bvrA的表达大大减弱，但仍可检测到。相比之下，96个HPF GATA-1变异体在造血组织中显示bvrA和bvrb表达增加。最后，参与NADPH产生和维持的酶的时间表达模式与斑马鱼早期发育过程中细胞氧化还原状态的已知变化一致。综上所述，这些数据表明，GATA-1和NRF2a在细胞应激加剧的早期发育阶段调节血红素降解酶方面发挥着不同的作用。
Heme oxygenase 1 (HMOX1) degrades heme into biliverdin, which is subsequently converted to bilirubin by biliverdin reductase (BVRa or BVRb) in a manner analogous to the classic anti-oxidant glutathione-recycling pathway. To gain a better understanding of the potential antioxidant roles the BVR enzymes may play during development, the spatiotemporal expression and transcriptional regulation of zebrafish hmox1a, bvra and bvrb were characterized under basal conditions and in response to pro-oxidant exposure. All three genes displayed spatiotemporal expression patterns consistent with classic hematopoietic progenitors during development. Transient knockdown of Nrf2a did not attenuate the ability to detect bvra or bvrb by ISH, or alter spatial expression patterns in response to cadmium exposure. While hmox1a:mCherry fluorescence was documented within the intermediate cell mass, a transient location of primitive erythrocyte differentiation, expression was not fully attenuated in Nrf2a morphants, but real-time RT-PCR demonstrated a significant reduction in hmox1a expression. Furthermore, Gata-1 knockdown did not attenuate hmox1a:mCherry fluorescence. However, while there was a complete loss of detection of bvrb expression by ISH at 24 hpf, bvra expression was greatly attenuated but still detectable in Gata-1 morphants. In contrast, 96 hpf Gata-1 morphants displayed increased bvra and bvrb expression within hematopoietic tissues. Finally, temporal expression patterns of enzymes involved in the generation and maintenance of NADPH were consistent with known changes in the cellular redox state during early zebrafish development. Together, these data suggest that Gata-1 and Nrf2a play differential roles in regulating the heme degradation enzymes during an early developmental period of heightened cellular stress.