Autophagic processes increase during senescence in cultured sheep neurons and astrocytes

Abstract

A possible response to aging is autophagy, a self-digestion process in which portions of cytoplasm are encapsulated by double-membrane-bound structures and delivered to lysosome for degradation. A previous work of our group showed that astrocytes under starving conditions are characterized by a higher upregulation of the marker of autophagy LC3 II than neurons. Aim of the present work was to evaluate LC3 II expression in an aging model consisting in fetal sheep neurons and astrocytes at 10, 20 and 30 days of culture. Such model has been validated by a remarkable activity of β-galactosidase, commonly used to reveal cell aging. LC3 II immunoreactivity in neurons and astrocytes progressively increased with time but differences were observed on the basis of cell density. Indeed, LC3 II immunoreactivity is higher in clusters of neurons and astrocytes and this may be due to the fact that cell-cell contact would represent a second stress in addition to aging itself. Both cell types displayed a reduction in LC3 II signal in nuclei, and a corresponding strengthening in the cytoplasm with time. This may be due to the need of aged cells to remove damaged cytoplasmic components through autophagic processes. Such variation in LC3 II localization could be caused by migration from the nucleus to cytoplasm as well as possible de novo intracytoplasmic production. The present work based on sheep neural cells in vitro may represent a helpful tool in the studies on aging processes in which autophagy plays a remarkable role.

Impaired Mitophagy in Neurons and Glial Cells during Aging and Age-Related Disorders

“…For example, a deficit in Atg5 suppresses astrocyte differentiation, whereas its higher expression leads to an excessive increase in astrocyte numbers [ 72 ]. The most commonly used marker of autophagy is LC3, namely the ratio of its soluble (LC3I) to lipid-bound (LC3II) forms [ 105 ]. Cell models show that aging is characterized by higher expression of LC3 II both in neurons and astrocytes, while in starving conditions, astrocytes demonstrate increased LC3 II expression compared with neurons [ 105 ].…”

A journal of histochemistry as a forum for non-histochemical scientific societies

“…[49][50][51] The basic cell mechanisms of apoptosis and autophagy proved to play key roles during the pre-and postnatal development of the cochlea in rodents 27,52,53 as well as during senescence in culture of sheep neurons and astrocytes. 54 The effect of cadmium was found to alter glial architecture in the lizard brain, 55 and to induce neurodegeneration in zebrafish embryos and adults, 56 while the effects of drug administration on the brain following trauma were studied in rat. 57 A modified method of combined fixation in formalin and formic acid was described to obtain high quality immunolabeling of long-stored paraffinembedded autoptic adult brains, 58 and original staining protocols were proposed to visualize on thick brain sections the cortical microinfarcts that frequently remain undetected by standard neuroimaging protocols.…”

Ovine fetuses from slaughterhouses: A useful source for neural cell primary cultures

“…9,10, Cell cultures carried out from sheep brain represent another important tool for studying neural cell biology instead of the usual cell cultures obtained from rats. 11,12,13,14,15 Actually, in addition to ovine cultured cells, human-derived cell models exist, including stem cell-derived primary neuronal and glial cultures, as well as sophisticated 3D organoids. 16,17,18 However, such models may be expensive and/or need a high degree of manipulation in order to get differentiated neural cells.…”