G alpha 13 Contributes to LPS-Induced Morphological Alterations and Affects Migration of Microglia

Microglia are the resident immune cells of the CNS that are activated in response to a variety of stimuli. This phenotypical change is aimed to maintain the local homeostasis, also by containing the insults and repair the damages. All these processes are tightly regulated and coordinated and a failure in restoring homeostasis by microglia can result in the development of neuroinflammation that can facilitate the progression of pathological conditions. Indeed, chronic microglia activation is commonly recognized as a hallmark of many neurological disorders, especially at an early stage. Many complex pathways, including cytoskeletal remodeling, are involved in the control of the microglial phenotypical and morphological changes that occur during activation. In this work, we focused on the small GTPase G alpha 13 and its role at the crossroad between RhoA and Rac1 signaling when microglia is exposed to pro-inflammatory stimulation. We propose the direct involvement of G alpha 13 in the cytoskeletal rearrangements mediated by FAK, LIMK/cofilin, and Rac1 during microglia activation. In fact, we show that G alpha 13 knockdown significantly inhibited LPS-induced microglial cell activation, in terms of both changes in morphology and migration, through the modulation of FAK and one of its downstream effectors, Rac1. In conclusion, we propose G alpha 13 as a critical factor in the regulation of morphological and functional properties of microglia during activation, which might become a target of intervention for the control of microglia inflammation.