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Brain aging is characterized by chronic neuroinflammation caused by activation of glial cells, mainly microglia, leading to alterations in homeostasis of the central nervous system. Microglial cells are constantly surveying their environment to detect and respond to diverse signals. During aging, microglia undergoes a process of senescence, characterized by loss of ramifications, spheroid formation, and fragmented processes, among other abnormalities. Therefore, the study of changes in microglia during is of great relevance to understand age-related declines in cognitive and motor function. We have targeted the deleterious effects of aging by implementing IGF-1 gene transfer, employing recombinant adenoviral vectors (RAds) as a delivery system. In this study, we performed intracerebroventricular (ICV) RAd-IGF-1 or control injection on aged female rats and evaluated its effect on caudate-putamen unit (CPu) gene expression and inflammatory state. Our results demonstrate that IGF-1 overexpression modified aged microglia of the CPu towards an anti-inflammatory condition increasing the proportion of double immuno-positive Iba1+Arg1+ cells. We also observed that phosphorylation of Akt was increased in animals treated with RAd-IGF-1. Moreover, IGF-1 gene transfer was able to regulate CPu pro-inflammatory environment in female aged rats by down-regulating the expression of genes typically overexpressed during aging. RNA-Seq data analysis identified 97 down-modulated DEG in the IGF-1 group as compared to the DsRed one. Interestingly, 12 of these DEG are commonly overexpressed during aging, and 9 out of 12 are expressed in microglia/macrophages and are involved in different processes that lead to neuroinflammation and/or neuronal loss. Finally, we observed that IGF-1 overexpression led to an improvement in motor functions. Although further studies are necessary, with the present results, we conclude that IGF-1 gene transfer is modifying both the pro-inflammatory environment and activation of microglia/macrophages in CPu. In this regard, IGF-1 gene transfer could counteract the neuroinflammatory effects associated with aging and improve motor functions in senile animals. © 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Brain aging is characterized by chronic neuroinflammation caused by activation of glial cells, mainly microglia, leading to alterations in homeostasis of the central nervous system. Microglial cells are constantly surveying their environment to detect and respond to diverse signals. During aging, microglia undergo a process of senescence, characterized by loss of ramifications, spheroid formation, and fragmented processes, among other abnormalities. Therefore, the study of microglia senescence is of great relevance to understand age‐related declines in cognitive and motor function.We have targeted the deleterious effects of aging by implementing gene therapy with IGF-1, employing recombinant adenoviral vectors (RAds) as a delivery system. In this study, we performed intracerebroventricular (ICV) IGF-1 gene therapy on aged female rats and evaluated its effect on Caudate-Putamen unit (CPu) gene expression and inflammatory state. IGF-1 gene therapy modified senescent microglia of the CPu towards an anti-inflammatory state increasing the proportion of Iba1+Arg1+ cells. Moreover, IGF-1 gene therapy was able to regulate the pro-inflammatory environment of CPu in female aged rats by down-regulating the expression of genes typically over-expressed during aging. Our results demonstrate that, ICV IGF-1 gene therapy, is capable to modulate microglia cells and CPu gene expression, leading to an improvement in motor function., Instituto de Investigaciones Bioquímicas de La Plata

This review provides an original overview of glial cells functions on the central nervous system and their relationship with neuroinflammation. We decided to correlate astrocytes, microglia and oligodendrocytes functions with neurons interplay, and refer it to Tango genre and dance. Furthermore, this revision summarizes studies that support the roles of glial cells in neuroinflammation under different conditions, such as aging and main neurodegenerative diseases in particular, Parkinson’s Disease and Alzheimer’s Disease., Instituto de Investigaciones Bioquímicas de La Plata