Characterization of Pro-inflammatory and Anti-inflammatory Microglia in the Anterior Cingulate Cortex in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is associated with functional abnormalities of the anterior cingulate cortex (ACC), a brain area that mediates social behavior. Given evidence of a role of inflammation in ASD, markers of pro-inflammatory and anti-inflammatory microglia were studied using postmortem ACC tissues from ASD and age-matched typically developed control donors. Gene expression levels of pro-inflammatory (CD68, HLA-DRA, IL1B, NOS2, PTGS2) and anti-inflammatory (ARG1, IGF1, MRC1, PPARG) microglial genes were measured using quantitative real-time PCR. Additionally, brain sections were immunohistochemically stained for a microglial marker. Expression levels of IGF1 were modestly higher, while the expression of MRC1 was modestly lower in ASD donors when compared to control donors. No other differences in gene expression levels between the two groups of donors were observed. Statistical significance for changes in expression levels IGF1 and MRC1 did not survive correction for multiple comparisons. Further research on anti-inflammatory microglial involvement in ASD is warranted