JAMES H. MILLONIG
Senior Associate Dean
Rutgers Graduate School of Biomedical Sciences
Ph.D., 1993, Princeton University
Telephone: (848) 445-9852
Fax: (732) 235-4850
Autism and Gpr161
Autism comprises multiple brain dysfunctions (poor social interactions, repetitive behaviors as well as deficits in language, cognition, sensory-motor integration etc). These multiple dysfunctions suggest that there might be common and widespread disruptions in cellular processes and molecular pathways. Autism risk is also polygenic which cannot be modeled properly in the mouse, and some autism phenotypes are not easily studied in the mouse such as language. Disease modeling of autism should then include relevant human cells and the advent of iPSCs now makes this possible.
While previous studies have demonstrated the usefulness of iPSCs for studying monogenic autism, few have applied iPSC technology to idiopathic autism. We have generated 8 sib-pairs from idiopathic autism families. To reduce potential heterogeneity, our iPSCs are generated from families with autism and a separate language disorder called Specific Language Impairment (SLI). Individuals with autism and SLI have similar language deficits but unlike autism, SLI only affects language. Unaffected sibs are used as controls and only individuals with a narrow diagnosis of autism have been examined. To ensure reproducibility, each analysis has been performed on three biological replicates from control and autism iPSCs and then technical replicates are also conducted for each assay. We have observed autism-specific phenotypes in proliferation, neurite outgrowth and cell migration. Deficits in PKA-cAMP signaling has been observed, which is supported by metabolomic and whole genome sequencing results. Growth factors and small molecules have already been identified that can rescue some of these phenotypes.
We now plan to investigate whether these defects are commonly observed in idiopathic autism, are shared with SLI, which will help us define phenotypic subgroups. Finally to identify potential biomarkers that define our neurobiological phenotypes, we will define cerebrocortical-somatic function using a new statistical platform that analyzes data obtained from high-resolution motion capture sensors and EEG. These studies will provide a better understanding of disease etiology and heterogeneity, and will also identify new molecular pathways to target to alter disease progression or reduce disability.
My laboratory in collaboration with Bev Paigen’s laboratory at The Jackson Laboratories positionally cloned the spontaneous mouse mutant called vacuolated lens (vl). A single allele of the vl mutation arose on the C3H/HeSnJ inbred background. Vl homozygotes display congenital cataracts and neural tube defects (NTDs). We determined that a mutation in the orphan G protein coupled receptor, Gpr161, results in the Gpr161vl phenotypes. Characterization of the Gpr161vl mutation indicates that C terminal tail of Gpr161 is truncated, leading to multiple effects on the protein including reduced receptor-mediated endocytosis.
Interestingly, the Gpr161vl phenotypes are also multi-genic. On the C3H background, 100% of Gpr161vl/vl homozygotes display a phenotype. However, when the Gpr161vl mutation was crossed onto different genetic backgrounds (C57BL6/J, Mus castaneus (CAST/Ei) and Mus molossinus (MOLF/Ei)) the mutant phenotypes are rescued. We mapped 5 different vl modifier loci on these different genetic backgrounds (Modifiers of vacuolated lens, Modvl1-5). Congenic analysis has determined that Modvl5MOLF rescues the NTD defects while Modvl4MOLF rescues the congenital cataract phenotype. The congenic analysis also helped us determine that Gpr161 regulates the retinoic acid (RA) pathway during development.
Li BI, Ababon MR, Matteson PG, Lin Y, Nanda V, Millonig JH. (2017) Congenital cataract in Gpr161vl/vl mice is modified by proximal chromosome 15. PLoS One 12:e0170724
Wiseman JA, Meng Y, Nemtsova Y, Matteson PG, Millonig JH, Moore DF, Sleat DE, and Lobel, P. (2017) Chronic enzyme replacement to the brain of a late infantile neuronal ceroid lipofuscinosis mouse has differential effects on phenotypes of disease. Mol Ther Methods Clin Dev 4:204–212
Ababon MR, Li BI, Matteson PG, Millonig JH. (2016) Quantitative measurement of relative retinoic acid levels in E8.5 embryos and neurosphere cultures using the F9 RARE-LacZ cell-based reporter assay. J Vis Exp doi: 10.3791/54443
Li BI, Matteson PG, Ababon MF, Nato AQ, Jr., Lin Y, Nanda V, Matise TC, Millonig JH. (2015) The orphan GPCR, Gpr161, regulates the retinoic acid and canonical Wnt pathways during neurulation. Dev Biol 402:17-31
Genestine M, Lin L, Durens M, Yan Y, Jiang Y, Prem S, Bailoor K, Kelly B, Sonsalla PK, Matteson PG, Silverman J, Crawley JN, Millonig JH, DiCicco-Bloom E. (2015) Engrailed-2 (En2) deletion produces multiple neurodevelopmental defects in monoamine systems, forebrain structures and neurogenesis and behavior. Hum Mol Genet 24:5805-27