Mouse Astrocytes from CD1

Activity of the astrocyte-neuronal lactate shuttle (ANLS) in the anterior cingulate cortex (ACC) has been proposed to be necessary for chronic pain development in inflamm... More

Activity of the astrocyte-neuronal lactate shuttle (ANLS) in the anterior cingulate cortex (ACC) has been proposed to be necessary for chronic pain development in inflammatory pain models but is yet to be investigated in chronic neuropathic pain. A spared nerve injury (SNI) model of chronic neuropathic pain was utilized to examine the involvement of the ANLS in male and female mice. Knockdown of a key lactate transporter, monocarboxylate transporter 4 (MCT4), was performed in vitro and in vivo to assess the impact of lactate shuttling inhibition. L-lactate levels in the ACC were increased in SNI in males, but not females, which was accompanied by sex-specific increases in ANLS and neuroplasticity-related protein markers. MCT4 knockdown in vivo led to sex-specific changes in these markers. In contrast, MCT4 knockdown in vitro did not effectively reduce protein levels in varied experimental conditions, demonstrating the complex role of the ANLS in multiple cell types. Keywords: chronic pain, astrocytes, astrocyte-neuronal lactate shuttle, cnterior cingulate cortex, MCT4 Less

Microglial cells (MGs), originally derived from progenitor cells in a yolk sac during early development, are glial cells located in a physiological and pathological brain... More

Microglial cells (MGs), originally derived from progenitor cells in a yolk sac during early development, are glial cells located in a physiological and pathological brain. Since the brain contains various cell types, MGs could frequently interact with different cells, such as astrocytes (ACs), pericytes (PCs), and endothelial cells (ECs). However, how microglial traits are regulated via cell–cell interactions by ACs, PCs, or ECs and how they are different depending on the contacted cell types is unclear. This study aimed to clarify these questions by coculturing MGs with ACs, PCs, or ECs using mouse brain-derived cells, and microglial phenotypic changes were investigated under culture conditions that enabled direct cell–cell contact. Our results showed that ACs or PCs dose-dependently increased the number of MG, while ECs decreased it. Microarray and gene ontology analysis showed that cell fate-related genes (e.g., cell cycle, proliferation, growth, death, and apoptosis) of MGs were altered after a cell–cell contact with ACs, PCs, and ECs. Notably, microarray analysis showed that several genes, such as gap junction protein alpha 1 (Gja1), were prominently upregulated in MGs after coincubation with ACs, PCs, or ECs, regardless of cell types. Similarly, immunohistochemistry showed that an increased Gja1 expression was observed in MGs after coincubation with ACs, PCs, or ECs. Immunofluorescent and fluorescence-activated cell sorting analysis also showed that calcein-AM was transferred into MGs after coincubation with ACs, PCs, or ECs, confirming that intercellular interactions occurred between these cells. However, while Gja1 inhibition reduced the number of MGs after coincubation with ACs and PCs, this was increased after coincubation with ECs; this indicates that ACs and PCs positively regulate microglial numbers via Gja1, while ECs decrease it. Results show that ACs, PCs, or ECs exert both common and specific cell type-dependent effects on MGs through intercellular interactions. These findings also suggest that brain microglial phenotypes are different depending on their surrounding cell types, such as ACs, PCs, or ECs. Less