Proteomic explorations of autism spectrum disorder.

Proteomics, the large-scale study of protein expression in cells and tissues, is a powerful tool to study the biology of clinical conditions and has provided significant insights in many experimental systems. Herein, we review the basics of proteomic methodology and discuss challenges in using proteomic approaches to study autism. Unlike other experimental approaches, such as genomic approaches, there have been few large-scale studies of proteins in tissues from persons with autism. Most of the proteomic studies on autism used blood or other peripheral tissues; few studies used brain tissue. Some studies found dysregulation of aspects of the immune system or of aspects of lipid metabolism, but no consistent findings were noted. Based on the challenges in using proteomics to study autism, we discuss considerations for future studies. Apart from the complex technical considerations implicit in any proteomic analysis, key nontechnical matters include attention to subject and specimen inclusion/exclusion criteria, having adequate sample size to ensure appropriate powering of the study, attention to the state of specimens prior to proteomic analysis, and the use of a replicate set of specimens, when possible. We conclude by discussing some potentially productive uses of proteomics, potentially coupled with other approaches, for future autism research including: (1) proteomic analysis of banked human brain specimens; (2) proteomic analysis of tissues from animal models of autism; and (3) proteomic analysis of induced pluripotent stem cells that are differentiated into various types of brain cells and neural organoids. Autism Res 2017, 10: 1460-1469. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.