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Published June 6, 2022 | Published + Supplemental Material
Journal Article Open

Transduction of Systemically Administered Adeno-Associated Virus in the Colonic Enteric Nervous System and c-Kit Cells of Adult Mice

Abstract

Systemic delivery of adeno-associated virus (AAV) vectors transduces the enteric nervous system. However, less is known on the mapping and morphological and neurochemical characterization in the adult mouse colon. We used AAV9-CAG-GFP (AAV9) and AAV-PHP.S-hSyn1-tdTomato farnesylated (PHP.S-tdTf) to investigate the segmental distribution, morphologies and neurochemical coding of the transduction. The vectors were retro-orbitally injected in male and female adult mice, and 3 weeks later, the colon was prepared for microcopy with or without immunohistochemistry for neuronal and non-neuronal markers. In contrast to the distributions in neonatal and juvenile rodents, the AAV transduction in neurons and/or nerve fibers was the highest in the proximal colon, decreased gradually in the transverse, and was sparse in the distal colon without difference between sexes. In the proximal colon, the AAV9-transduced myenteric neurons were unevenly distributed. The majority of enteric neurons did not have AAV9 expression in their processes, except those with big soma with or without variously shaped dendrites, and a long axon. Immunolabeling demonstrated that about 31% neurons were transduced by AAV9, and the transduction was in 50, 28, and 31% of cholinergic, nitrergic, and calbindin-positive myenteric neurons, respectively. The nerve fiber markers, calcitonin gene-related peptide alpha, tyrosine hydroxylase or vasoactive intestinal polypeptide co-localized with AAV9 or PHP.S-tdTf in the mucosa, and rarely in the myenteric plexus. Unexpectedly, AAV9 expression appeared also in a few c-Kit immunoreactive cells among the heavily populated interstitial cells of Cajal (ICC). In the distal colon, the AAV transduction appeared in a few nerve fibers mostly the interganglionic strands. Other types of AAV9 and AAV-PHP vectors induced a similar colonic segmental difference which is not colon specific since neurons were transduced in the small intestine and gastric antrum, while little in the gastric corpus and none in the lower esophagus. Conclusion: These findings demonstrate that in adult mice colon that there is a rostro-caudal decrease in the transduction of systemic delivery of AAV9 and its variants independent of sex. The characterization of AAV transduction in the proximal colon in cholinergic and nitrergic myenteric neurons along with a few ICC suggests implications in circuitries regulating motility.

Additional Information

© 2022 Wang, Yuan, Challis, Ravindra Kumar and Taché. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Received: 26 February 2022; Accepted: 19 April 2022; Published: 06 June 2022. We thank Dr. V. Gradinaru (Division of Biology, California Institute of Technology, Pasadena, CA) for the supply of AAV, Ms. Honghui Liang for her excellent technical assistance and Dr. Songlin Li's contribution to the image acquisition. This work was supported by NIH SPARC award OT2OD24899, Department of Veterans Affair Rehabilitation Research and Development grant 1RX001685, Veterans Administration Senior Research Career Scientist Award, P30 NIHDDK-41301 CURE: Digestive Diseases Research Core Center Grant. Author Contributions. LW and YT initiated the studies and contributed to the conception, study design, and writing the manuscript. LW conducted the experiments, acquired and segmented the images, analyzed the data, and prepared the figures. CC and SR contributed the AAV-PHP.S vectors production. CC edited the manuscript critically. P-QY participated in data interpretation and edited the manuscript. All authors contributed to the article and approved the submitted version. Data Availability Statement. The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation. Ethics Statement. The animal study was reviewed and approved by Animal Research Committee at Veterans Affairs Greater Los Angeles Healthcare System. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Attached Files

Published - fnana-16-884280.pdf

Supplemental Material - Presentation_1_Transduction_of_Systemically_Administered_Adeno-Associated_Virus_in_the_Colonic_Enteric_Nervous_System_and_c-Kit_Cells_of_Adult_Mice.pdf

Files

Presentation_1_Transduction_of_Systemically_Administered_Adeno-Associated_Virus_in_the_Colonic_Enteric_Nervous_System_and_c-Kit_Cells_of_Adult_Mice.pdf

Additional details

Created:
August 22, 2023
Modified:
October 24, 2023