Pulliero Alessandra, Seydel Anke, Camoirano Anna, Saccà Sergio Claudio, Sandri Marco, Izzotti Alberto
Department of Health Sciences, University of Genoa, Genoa, Italy.
Dulbecco Telethon Institute, Venetian Institute of Molecular Medicine, Padua, Italy.
PLoS One. 2014 Jun 19;9(6):e98106. doi: 10.1371/journal.pone.0098106. eCollection 2014.
Autophagy is an intracellular lysosomal degradation process induced under stress conditions. Autophagy also plays a major role in ocular patho-physiology. Molecular aging does occur in the trabecular meshwork, the main regulator of aqueous humor outflow, and trabecular meshwork senescence is accompanied by increased oxidative stress. However, the role of autophagy in trabecular meshwork patho-physiology has not yet been examined in vivo in human ocular tissues. The purpose of the herein presented study is to evaluate autophagy occurrence in ex-vivo collected human trabecular meshwork specimens and to evaluate the relationship between autophagy, oxidative stress, and aging in this tissue. Fresh trabecular meshwork specimens were collected from 28 healthy corneal donors devoid of ocular pathologies and oxidative DNA damage, and LC3 and p62 protein expression analyzed. In a subset of 10 subjects, further to trabecular meshwork proteins, the amounts of cathepesin L and ubiquitin was analyzed by antibody microarray in aqueous humor. Obtained results demonstrate that autophagy activation, measured by LC3II/I ratio, is related with. oxidative damage occurrence during aging in human trabecular meshwork. The expression of autophagy marker p62 was lower in subjects older than 60 years as compared to younger subjects. These findings reflect the occurrence of an agedependent increase in the autophagy as occurring in the trabecular meshwork. Furthermore, we showed that aging promotes trabecular-meshwork senescence due to increased oxidative stress paralleled by autophagy increase. Indeed, both oxidative DNA damage and autophagy were more abundant in subjects older than 60 years. These findings shed new light on the role of oxidative damage and autophagy during trabecular-meshwork aging.
自噬是一种在应激条件下诱导的细胞内溶酶体降解过程。自噬在眼部病理生理学中也起着重要作用。小梁网是房水流出的主要调节者，分子衰老确实会在小梁网中发生，并且小梁网衰老伴随着氧化应激增加。然而，自噬在小梁网病理生理学中的作用尚未在人体眼部组织中进行体内研究。本研究的目的是评估体外收集的人小梁网标本中的自噬发生情况，并评估该组织中自噬、氧化应激和衰老之间的关系。从28名没有眼部疾病和氧化性DNA损伤的健康角膜供体中收集新鲜小梁网标本，并分析LC3和p62蛋白表达。在10名受试者的子集中，除了小梁网蛋白外，还通过抗体微阵列分析房水中组织蛋白酶L和泛素的含量。获得的结果表明，通过LC3II/I比率测量的自噬激活与人类小梁网衰老过程中的氧化损伤发生有关。与年轻受试者相比，60岁以上受试者中自噬标志物p62的表达较低。这些发现反映了小梁网中自噬随年龄增长而增加的情况。此外，我们表明衰老通过氧化应激增加和自噬增加促进小梁网衰老。事实上，60岁以上受试者的氧化性DNA损伤和自噬都更为丰富。这些发现为氧化损伤和自噬在小梁网衰老过程中的作用提供了新的线索。
