Keratin intermediate filaments in the colon: guardians of epithelial homeostasis

Polari, Lauri; Alam, Catharina M.; Nystr�m, Joel H.; Heikkil�, Taina; Tayyab, Mina; Baghestani, Sarah; Toivola, Diana M.

Abstract

Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future.

Citation

Polari, L., Alam, C. M., Nyström, J. H., Heikkilä, T., Tayyab, M., Baghestani, S., & Toivola, D. M. (2020). Keratin intermediate filaments in the colon: guardians of epithelial homeostasis. International Journal of Biochemistry and Cell Biology, 129, Article 105878. https://doi.org/10.1016/j.biocel.2020.105878

• Journal Article Type: Review
• Acceptance Date: Oct 29, 2020
• Online Publication Date: Nov 2, 2020
• Publication Date: 2020-12
• Deposit Date: May 6, 2022
• Publicly Available Date: May 6, 2022
• Journal: The International Journal of Biochemistry & Cell Biology
• Print ISSN: 1357-2725
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 129
• Article Number: 105878
• DOI: https://doi.org/10.1016/j.biocel.2020.105878
• Keywords: keratin, intermediate filament, inflammatory bowel disease, cytoskeleton, mouse model, cancer diagnostics
• Public URL: http://researchrepository.napier.ac.uk/Output/2869089