Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
Biochem Biophys Res Commun. 2012 Aug 17;425(1):100-6. doi: 10.1016/j.bbrc.2012.07.061. Epub 2012 Jul 20.
Neuroglobin (Ngb), a neuronal specific oxygen binding heme-globin, reported to be expressed at high levels in most layers of the murine retina. Ngb's function is presently unknown, but based on its high expression level and oxygen binding capabilities Ngb was proposed to function as an oxygen reservoir facilitating oxygen metabolism in highly active neurons or to function as a neuroprotectant. In the present study, we re-examined the expression pattern of Ngb in the retina using a highly validated antibody. Furthermore, intactness of retino-hypothalamic projections and the retinal expression level of Melanopsin and Tyrosine Hydroxylase were investigated in Ngb-null mice. Ngb-immunoreactivity was found in a few neurons of the ganglion cell and inner nuclear layers co-expressing Melanopsin and Tyrosine Hydroxylase, respectively. Ngb deficiency neither affected the level of Melanopsin and Tyrosine Hydroxylase proteins nor the intactness of PACAP-positive retinohypothalamic projections in the suprachiasmatic nucleus. Based on the present results, it seems unlikely that Ngb could have a major role in retinal oxygen homeostasis and neuronal survival under normal conditions. The present study suggests that a number of previously published reports have relied on antibodies with dubious specificity.
神经球蛋白（Ngb）是一种神经元特异性的氧结合血红素球蛋白，据报道在鼠视网膜的大多数层中高水平表达。Ngb 的功能目前尚不清楚，但基于其高表达水平和氧结合能力，Ngb 被提议作为一种氧库，以促进高活性神经元的氧代谢，或作为一种神经保护剂发挥作用。在本研究中，我们使用经过高度验证的抗体重新检查了 Ngb 在视网膜中的表达模式。此外，还研究了 Ngb 缺失小鼠中的视网膜神经投射的完整性以及黑视素和酪氨酸羟化酶的视网膜表达水平。Ngb 免疫反应性存在于分别表达黑视素和酪氨酸羟化酶的神经节细胞和内核层的少数神经元中。Ngb 缺乏既不影响黑视素和酪氨酸羟化酶蛋白的水平，也不影响视上核中 PACAP 阳性视网膜神经投射的完整性。基于目前的结果，Ngb 在正常情况下不太可能在视网膜氧平衡和神经元存活中发挥主要作用。本研究表明，以前发表的许多报告都依赖于特异性可疑的抗体。
