Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, New Zealand.
Sci Rep. 2017 Mar 13;7:44135. doi: 10.1038/srep44135.
Hyaluronan is a linear glycosaminoglycan that forms the backbone of perineuronal nets around neurons in the cerebral cortex. However, it remains controversial whether neurons are capable of independent hyaluronan synthesis. Herein, we examined the expression of hyaluronan and hyaluronan synthases (HASs) throughout cortical neuron development in vitro. Enriched cultures of cortical neurons were established from E16 rats. Neurons were collected at days in vitro (DIV) 0 (4 h), 1, 3, 7, 14, and 21 for qPCR or immunocytochemistry. In the relative absence of glia, neurons exhibited HAS1-3 mRNA at all time-points. By immunocytochemistry, puncta of HAS2-3 protein and hyaluronan were located on neuronal cell bodies, neurites, and lamellipodia/growth cones from as early as 4 h in culture. As neurons matured, hyaluronan was also detected on dendrites, filopodia, and axons, and around synapses. Percentages of hyaluronan-positive neurons increased with culture time to ~93% by DIV21, while only half of neurons at DIV21 expressed the perineuronal net marker Wisteria floribunda agglutinin. These data clearly demonstrate that neurons in vitro can independently synthesise hyaluronan throughout all maturational stages, and that hyaluronan production is not limited to neurons expressing perineuronal nets. The specific structural localisation of hyaluronan suggests potential roles in neuronal development and function.
透明质酸是一种线性糖胺聚糖，构成大脑皮层神经元周围神经周细胞网的骨架。然而，神经元是否能够独立合成透明质酸仍然存在争议。本文在体外研究了透明质酸和透明质酸合酶（HASs）在皮质神经元发育过程中的表达。从 E16 大鼠中分离培养富含皮质神经元的细胞。神经元分别在体外培养 0（4h）、1、3、7、14 和 21 天，通过 qPCR 或免疫细胞化学法进行收集。在没有胶质细胞的相对情况下，神经元在所有时间点都表达 HAS1-3 mRNA。通过免疫细胞化学，HAS2-3 蛋白和透明质酸的斑点位于神经元胞体、突起和从培养 4h 开始的片状伪足/生长锥上。随着神经元成熟，透明质酸也在树突、丝状伪足和轴突上以及突触周围被检测到。在培养 21 天时，透明质酸阳性神经元的百分比增加到约 93%，而只有 21 天的神经元中有一半表达神经周细胞网标记物槐凝集素。这些数据清楚地表明，体外神经元可以在所有成熟阶段独立合成透明质酸，并且透明质酸的产生不限于表达神经周细胞网的神经元。透明质酸的特定结构定位表明其在神经元发育和功能中的潜在作用。
