PDF(Pubmed)
Abstract：
Polyamine (PA) spermidine (SPD) plays a crucial role in aging. Since SPD accumulates in glial cells, particularly in Müller retinal cells (MCs), the expression of the SPD-synthesizing enzyme spermidine synthase (SpdS) in Müller glia and age-dependent SpdS activity are not known. We used immunocytochemistry, Western blot (WB), and image analysis on rat retinae at postnatal days 3, 21, and 120. The anti-glutamine synthetase (GS) antibody was used to identify glial cells. In the neonatal retina (postnatal day 3 (P3)), SpdS was expressed in almost all progenitor cells in the neuroblast. However, by day 21 (P21), the SpdS label was pronouncedly expressed in multiple neurons, while GS labels were observed only in radial Müller glial cells. During early cell adulthood, at postnatal day 120 (P120), SpdS was observed solely in ganglion cells and a few other neurons. Western blot and semi-quantitative analyses of SpdS labeling showed a dramatic decrease in SpdS at P21 and P120 compared to P3. In conclusion, the redistribution of SpdS with aging indicates that SPD is first synthesized in all progenitor cells and then later in neurons, but not in glia. However, MCs take up and accumulate SPD, regardless of the age-associated decrease in SPD synthesis in neurons.
摘要：
多胺（PA）亚精胺（SPD）在衰老中起着至关重要的作用。由于SPD在神经胶质细胞中积累，特别是在穆勒视网膜细胞(MC)中，尚不清楚Müller神经胶质中SPD合成酶亚精胺合酶（SpdS）的表达和年龄依赖性SpdS活性。我们用了免疫细胞化学,Westernblot(WB),以及出生后第3、21和120天大鼠视网膜的图像分析。抗谷氨酰胺合成酶(GS)抗体用于鉴定神经胶质细胞。在新生儿视网膜（出生后第3天（P3）），SpdS在成神经细胞的几乎所有祖细胞中表达。然而,第21天（P21）SpdS标签在多个神经元中明显表达，而GS标记仅在放射状Müller胶质细胞中观察到。在细胞成年早期，出生后第120天（P120），仅在神经节细胞和一些其他神经元中观察到SpdS。Western印迹和SpdS标记的半定量分析显示,与P3相比,在P21和P120处的SpdS显著降低。总之,SpdS随衰老的再分布表明，SPD首先在所有祖细胞中合成，然后在神经元中合成，但不是在胶质细胞里.然而,MC吸收和积累SPD，与年龄相关的神经元SPD合成降低无关。
