Analysis of gastorintestinal problems in autism mouse models

2020 Fiscal Year Annual Research Report

• Project/Area Number: 20F20704
• Research Institution: Kobe University
• Principal Investigator: 内匠 透 神戸大学, 医学研究科, 教授 (00222092)
• Co-Investigator(Kenkyū-buntansha): BALASURIYA BALASURIYA 神戸大学, 医学研究科, 外国人特別研究員
• Project Period (FY): 2020-11-13 – 2023-03-31
• Keywords: autism / intestine

Outline of Annual Research Achievements

Autism is a highly prevalent neurological disorder characterized by impaired social interactions and stereotyped or repetitive behaviours. Autism-associated GI symptoms frequently present from early childhood to adulthood and patients with autism are approximately four-fold more likely to be hospitalized with GI disorders. GI function is regulated by the intrinsic enteric nervous system (ENS), a complex network of neurons extending along the length of the GI tract arranged in two plexuses, the submucosal and myenteric plexuses that predominantly regulate gut secretion and motility, respectively. We will characterize the GI phenotype in two preclinical models of autism (CHD8 and 15q mice) in order to identify therapeutic targets to treat GI dysfunction.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

I. Established in vivo total gastrointestinal (GI) transit and small intestinal transit (by gavaging Carmine red dye) experiments.-Total GI transit was slower in 15q dup mice compared to WT adult mice (176±19 mins and 96±10 mins respectively, p=0.022, n=3) - Small intestinal transit was not different between 15q dup and WT mice (0.94±0.1 and 0.62±0.2 as a ratio of dye front/small intestinal length respectively, p=0.22, n=3)
II. Established whole mount immunofluorescence to study neurochemistry of enteric neuron. - Compared total number of neurons per ganglion (using pan-neuronal marker Hu C/D), percentage of neuronal nitric oxide synthase and GABA expressing neurons in the myenteric plexus of the colon between WT and 15q dup mice.
(Total number of neurons/ganglion 29±4 and 29±2 respectively, p=0.95, n=3; %nNOS expressing neurons/ganglion 15±1% and 16±1, p=0.34, n=3; %GABA expressing neurons/ganglion 40±1% and 43±2, p=0.52, n=3)
III.Breeding and maintaining15q Dup mice and genotyping.
IV.In the process of establishing the video imaging technique to study the colonic motility ex vivo.

Strategy for Future Research Activity

Study will include the characterisation of GI dysfunction of both 15q dup and CHD8 mutant mice.
I.Increase the number of replicates for in vivo total gastrointestinal (GI) transit and small intestinal transit analysis. II.Increase the number of replicates for the comparison of total number of neurons per ganglion, percentage of neuronal nitric oxide synthase and GABA expressing neurons.III.Compare the 5-HT and Choline Acetyl Transferase (ChAT) expressing neurons per ganglion. IV. Investigate the colonic motility using ex vivo video imaging technique for both adult and juvenile mice. V. Compare ENS related neurotransmitter and receptor gene expression using qPCR. VI. Perform a complete metabolomic analysis for the two groups. VII.Investigate the microbial dysbiosis in faces and caecal content.