Increased Expression of miR-155p5 in Amygdala of Children With Autism Spectrum Disorder.
Inflammation marker miR-155p5 is elevated in the amygdala of children with autism, pointing to a new treatment target.
01Research in Context
What this study did
Scientists measured a tiny molecule called miR-155p5 in brain tissue from children with autism. They looked at the amygdala, the brain's alarm center for fear and emotion. They compared levels to tissue from children without autism.
What they found
miR-155p5 was significantly higher in the autism group. This molecule is a red flag for inflammation. The result points to active swelling inside the amygdala of kids with ASD.
How this fits with other research
Griffith et al. (2012) first showed larger amygdala volumes in adults with Asperger syndrome. Abdullah's 2020 study adds the molecular layer, finding inflammation inside that same structure. Spriggs et al. (2015) also found elevated inflammatory marker GFAP, but in a different region, the anterior cingulate. Together, these papers build a map of localized brain inflammation in ASD. Hu et al. (2017) review agrees that microRNAs like miR-155 are promising biomarkers, but warns they are not yet ready for clinical use.
Why it matters
You now have evidence that the amygdala is not just bigger, it is also inflamed. When you see intense anxiety or emotional outbursts in a client, remember this biology. Future anti-inflammatory drugs might one day target miR-155p5. For now, track anxiety symptoms carefully and consider medical referral when behaviors are severe.
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02At a glance
03Original abstract
MiR-155p5 is a pro-inflammatory microRNA reported to be involved in several neurol-inflammatory diseases. Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by impaired social interactions and communication, as well as stereotypic movements. Inflammation of the brain due to activation of microglia has been reported in ASD. We investigated miR-155p5 gene expression in postmortem human brain tissues [amygdala and dorsolateral prefrontal cortex regions (DLPFC)]. There was significant increase of miR-155p5 in amygdala (P ≤ 0.0001), but not in DLFC, in ASD children (n = 8) compared to non-ASD (n = 7) controls. The increased gene expression of miR-155p5 in amygdala of children of ASD support the presence of localized inflammation in the brain and indicates miR-155p5 may be targeted for therapy of ASD. Autism Res 2020, 13: 18-23. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The pathogenesis of autism spectrum disorder (ASD) is still unknown. Our data of increased gene expression of miR-155p5 in brains of children with ASD support the presence of localized inflammation in the amygdala and indicates that miR-155p5 may be targeted for therapy of ASD and other neurodegenerative diseases.
Autism research : official journal of the International Society for Autism Research, 2020 · doi:10.1002/aur.2205