SHANK2 Mutations Result in Dysregulation of the ERK1/2 Pathway in Human Induced Pluripotent Stem Cells-Derived Neurons and Shank2(−/−) Mice

Abstract

SHANK2 (ProSAP1) is a postsynaptic scaffolding protein of excitatory synapses in the central nervous system and implicated in the development of autism spectrum disorders (ASD). Patients with mutations in SHANK2 show autism-like behaviors, developmental delay, and intellectual disability. We generated human induced pluripotent stem cells (hiPSC) from a patient carrying a heterozygous deletion of SHANK2 and from the unaffected parents. In patient hiPSCs and derived neurons SHANK2 mRNA and protein expression was reduced. During neuronal maturation, a reduction in growth cone size and a transient increase in neuronal soma size were observed. Neuronal proliferation was increased, and apoptosis was decreased in young and mature neurons. Additionally, mature patient hiPSC-derived neurons showed dysregulated excitatory signaling and a decrease of a broad range of signaling molecules of the ERK-MAP kinase pathway. These findings could be confirmed in brain samples from Shank2(−/−) mice, which also showed decreased mGluR5 and phospho-ERK1/2 expression. Our study broadens the current knowledge of SHANK2-related ASD. We highlight the importance of excitatory-inhibitory balance and mGluR5 dysregulation with disturbed downstream ERK1/2 signaling in ASD, which provides possible future therapeutic strategies for SHANK2-related ASD.

Identification of a Novel SHANK2 Pathogenic Variant in a Patient with a Neurodevelopmental Disorder

“…They observed a reduction in growth cone size and a transient increase in neuronal soma size during neuronal maturation in patients' derived cells. Furthermore, the extracellular signal-regulated kinase (ERK) pathway resulted dysregulated [31]. Another hiPSC study showed that human neurons with ASD-associated haploinsufficient SHANK2 mutations had increased synaptic connectivity relative to controls [32].…”

Microglial infiltration mediates cognitive dysfunction in rat models of hypothalamic obesity via a hypothalamic-hippocampal circuit involving the lateral hypothalamic area

“…For quantification of the microglial soma size, a polygonal region of interest containing only one soma was selected, and microglial soma size was measured manually in the immunostaining channel using ImageJ ( Ramírez et al, 2020 ). For the co-localization of Iba1 with SYN and PSD95 analysis, after background subtraction to remove camera noise, contrast enhancement was performed to increase the signal intensity and remove low-level background fluorescence, and the microglial soma contained the SYN/PSD95 was measured using the ImageJ ( Nelson et al, 2007 ; Lutz et al, 2021 ).…”

Does the current state of biomarker discovery in autism reflect the limits of reductionism in precision medicine? Suggestions for an integrative approach that considers dynamic mechanisms between brain, body, and the social environment

“…While at the group level, children with PMS responded significantly less often to both stimulus types, some PMS children in fact did respond to both, others almost to none, and others selectively to either social or nonsocial stimuli ((76), in press). Likewise, molecular studies now show that people with specifically SHANK3 point mutation actually have variable expressions of SHANK levels that cannot solely be attributed to deletion size or location (77).…”