CONSTITUTIVE ENDOTHELIAL NITRIC-OXIDE SYNTHASE GENE-EXPRESSION IS REGULATED DURING LUNG DEVELOPMENT
CONSTITUTIVE ENDOTHELIAL NITRIC-OXIDE SYNTHASE GENE-EXPRESSION IS REGULATED DURING LUNG DEVELOPMENT
复制标题
DOI：
10.1152/ajplung.1995.268.4.l589
复制
发表时间：
1995-04-01
影响因子：
4.9
通讯作者：
BLOCH, KD
中科院分区：
文献类型：
--
作者：
KAWAI, N;BLOCH, DB;BLOCH, KD
一氧化氮（NO）是一种由l -精氨酸由一氧化氮合酶（NOS）合成的自由基气体，是一种有效的血管扩张剂。一氧化氮似乎在围产期肺血管阻力变化中起重要作用。我们之前在人肺组织中发现了编码构成内皮NOS （ceNOS）亚型的mRNA。为了开始研究这种酶在围产期肺发育中的功能，我们测量了发育中的大鼠肺中ceNOS mRNA和免疫反应性。利用RNA印迹杂交技术，检测到胎儿晚期和出生后肺中大量的ceNOS mRNA。在出生后24小时内检测到最高水平，mRNA水平升高持续16天。相比之下，成年大鼠肺中发现的ceNOS mRNA水平要低得多。利用免疫印迹技术，发现ceNOS蛋白水平与mRNA水平相关。为了鉴定表达ceNOS基因的肺细胞类型，用地高辛标记的cRNA探针对1日龄和成年大鼠的肺切片进行原位杂交。在1日龄大鼠肺中，肺泡和浆膜上皮细胞以及中小血管内皮细胞中检测到ceNOS mRNA。相比之下，在成人肺中，在罕见的内皮细胞中检测到ceNOS基因转录物。这些观察结果表明，ceNOS基因表达在肺发育过程中受到调节，并且ceNOS可参与出生后肺血管阻力的降低。新生大鼠肺非内皮细胞中ceNOS基因的表达表明NO也可能参与肺发育中的非血管功能。
Nitric oxide (NO), a potent vasodilator, is a free-radical gas synthesized from L-arginine by nitric oxide synthases (NOS). NO appears to have an important role in perinatal changes in pulmonary vascular resistance. We previously identified mRNA encoding the constitutive endothelial NOS (ceNOS) isoform in human pulmonary tissue. To begin investigating functions of this enzyme in perinatal pulmonary development, we measured ceNOS mRNA and immunoreactivity in the developing rat lung. With the use of RNA blot hybridization, abundant pulmonary ceNOS mRNA was detected during the late fetal and postnatal period. The highest levels were detected within 24 h after birth, and elevated mRNA levels persisted for 16 days. In contrast, much lower levels of ceNOS mRNA were found in adult rat lung. With the use of immunoblot techniques, ceNOS protein levels were found to be correlated with mRNA levels. To identify the pulmonary cell types expressing the ceNOS gene, in situ hybridization with a digoxigenin-labeled cRNA probe was performed on sections from lungs of 1-day-old and adult rats. In lungs from 1-day-old rats, ceNOS mRNA was detected in alveolar and serosal epithelial cells as well as in endothelial cells lining small and medium-sized blood vessels. In contrast, in adult lungs, ceNOS gene transcripts were detected in rare endothelial cells. These observations suggest that ceNOS gene expression is regulated during lung development and that ceNOS is available to participate in the postnatal reduction of pulmonary vascular resistance. ceNOS gene expression in nonendothelial cells in the neonatal rat lung suggests that NO may also contribute to nonvascular functions in the developing lung.