The expression of equine keratins K42 and K124 is restricted to the hoof epidermal lamellae of Equus caballus.
Abstract: The equine hoof inner epithelium is folded into primary and secondary epidermal lamellae which increase the dermo-epidermal junction surface area of the hoof and can be affected by laminitis, a common disease of equids. Two keratin proteins (K), K42 and K124, are the most abundant keratins in the hoof lamellar tissue of Equus caballus. We hypothesize that these keratins are lamellar tissue-specific and could serve as differentiation- and disease-specific markers. Our objective was to characterize the expression of K42 and K124 in equine stratified epithelia and to generate monoclonal antibodies against K42 and K124. By RT-PCR analysis, keratin gene (KRT) KRT42 and KRT124 expression was present in lamellar tissue, but not cornea, haired skin, or hoof coronet. In situ hybridization studies showed that KRT124 localized to the suprabasal and, to a lesser extent, basal cells of the lamellae, was absent from haired skin and hoof coronet, and abruptly transitions from KRT124-negative coronet to KRT124-positive proximal lamellae. A monoclonal antibody generated against full-length recombinant equine K42 detected a lamellar keratin of the appropriate size, but also cross-reacted with other epidermal keratins. Three monoclonal antibodies generated against N- and C-terminal K124 peptides detected a band of the appropriate size in lamellar tissue and did not cross-react with proteins from haired skin, corneal limbus, hoof coronet, tongue, glabrous skin, oral mucosa, or chestnut on immunoblots. K124 localized to lamellar cells by indirect immunofluorescence. This is the first study to demonstrate the localization and expression of a hoof lamellar-specific keratin, K124, and to validate anti-K124 monoclonal antibodies.
Publication Date: 2019-09-24 PubMed ID: 31550264PubMed Central: PMC6759161DOI: 10.1371/journal.pone.0219234Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research article investigates the restricted expression of two keratin proteins, K42 and K124, within the lamellar tissue of the equine hoof in horses. The study explores the possibility that these keratins serve as specific indicators for differentiation and disease within the hoof’s tissue as well as the development of monoclonal antibodies against these keratins.
Context and Motivation
- The inner epithelium of a horse’s hoof folds into structures known as primary and secondary epidermal lamellae.
- This structure increases the intersection of the epithelium and dermis, however, it is susceptible to a disease known as laminitis.
- The lamellar tissue of the horse hoof abundantly expresses two types of keratin proteins K42 and K124.
- The researchers propose the idea that these keratins might be specific to lamellar tissue and could serve as disease-specific markers and a determinant of cell differentiation.
Objective of the Research
- The researchers’ primary goal was to understand the expression of K42 and K124 in the stratified epithelium of a horse’s hoof.
- This investigation also aimed at generating monoclonal antibodies for K42 and K124 which may possibly serve as a diagnostic tool for hoof ailments in future.
Methodology
- Keratin genes KRT42 and KRT124 were analyzed via RT-PCR to understand their expression patterns.
- In-situ hybridization studies were conducted to localize KRT124 within the tissue layers of the hoof.
- Monoclonal antibodies were generated against full-length recombinant equine K42 and K124 peptides to track their presence.
Results and Findings
- Both KRT42 and KRT124 expressions were found only in the lamellar tissue and not in cornea, haired skin or hoof coronet.
- KRT124 was localized primarily to the suprabasal layers of the lamellae and was not present in haired skin and hoof coronet.
- The monoclonal antibodies, specifically those against K124 showed selective binding with lamellar tissue without crossing reacting with proteins from other tissues.
Conclusion
- This is the first study that details the localization and expression patterns of a hoof lamellar-specific keratin, K124.
- The study also confirms the validity of anti-K124 monoclonal antibodies and their potential in revealing the health status of the hoof lamellar tissue.
Cite This Article
APA
Armstrong C, Cassimeris L, Da Silva Santos C, Micoogullari Y, Wagner B, Babasyan S, Brooks S, Galantino-Homer H.
(2019).
The expression of equine keratins K42 and K124 is restricted to the hoof epidermal lamellae of Equus caballus.
PLoS One, 14(9), e0219234.
https://doi.org/10.1371/journal.pone.0219234 Publication
Researcher Affiliations
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, Pennsylvania, United States of America.
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America.
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America.
- Department of Animal Sciences and University of Florida Genetics institute, University of Florida, Gainesville, Florida, United States of America.
- Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, Pennsylvania, United States of America.
MeSH Terms
- Animals
- Biomarkers
- Epidermis / metabolism
- Gene Expression
- Hoof and Claw / anatomy & histology
- Hoof and Claw / cytology
- Hoof and Claw / metabolism
- Horses
- Immunohistochemistry
- Keratins / genetics
- Organ Specificity / genetics
- Protein Isoforms
- RNA, Messenger / genetics
- RNA, Messenger / metabolism
Conflict of Interest Statement
A source of financial support for the archived samples used for this study, the Bernice Barbour Foundation, Inc., is considered a “commercial funder.” This does not alter our adherence to PLOS ONE policies on sharing data and materials. The Bernice Barbour Foundation, Inc. is a private tax-exempt philanthropic foundation and will not interfere with the full and objective presentation, peer review, editorial decision-making, or publication of this research article. This funding source does not place any restrictions on sharing of data and/or materials.
References
This article includes 53 references
- Schweizer J, Bowden PE, Coulombe PA, Langbein L, Lane EB, Magin TM. New consensus nomenclature for mammalian keratins. J Cell Biol 2006;174:169–74.
- Bragulla HH, Homberger DG. Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia. J Anatomy 2009;214:516–59.
- Ramms L, Fabris G, Windoffer R, Schwarz N, Springer R, Zhou C. Keratins as the main component for the mechanical integrity of keratinocytes. Proc Natl Acad Sci U S A 2013;110(46):18513–8.
- Homberg M, Magin TM. Beyond expectations: novel insights into epidermal keratin function and regulation. Int Rev Cell Mol Biol 2014;311:265–306.
- Lane EB, McLean WH. Keratins and skin disorders. J Pathol 2004;204(4):355–66.
- Liao H, Sayers JM, Wilson NJ, Irvine AD, Mellerio JE, Baselga E. A spectrum of mutations in keratins K6a, K16 and K17 causing pachyonychia congenita. J Derm Sci 2007;48:199–205.
- McGowan KM, Coulombe PA. Keratin 17 expression in the hard epithelial context of the hair and nail, and its relevance for the pachyonychia congenita phenotype. J Invest Dermatol 2000;114(6):1101–7.
- Jin L, Wang G. Keratin 17: a critical player in the pathogenesis of psoriasis. Med Res Rev 2014;34(2):438–54.
- Fuchs E, Weber K. Intermediate filaments: Structure, dynamics, function, and disease. Annu Rev Biochem 1994;63:345–82.
- Moll R, Divo M, Langbein L. The human keratins: biology and pathology. Histochem Cell Biol 2008;129:705–33.
- Lee CH, Coulombe PA. Self-organization of keratin intermediate filaments into cross-linked networks. J Cell Biol 2009;186(3):409–21.
- Davies HMS, Merritt JS, Thomason JJ. Biomechanics of the equine foot. In: Floyd AE, Mansmann RA, editors. Equine Podiatry.St. Louis, MO: Saunders Elsevier; 2007. p. 42–56.
- Roland ES, Hull ML, Stover SM. Design and demonstration of a dynamometric horseshoe for measuring ground reaction loads of horses during racing conditions. J Biomech 2005;38(10):2102–12.
- Bragulla H, Hirschberg RM. Horse hooves and bird feathers: Two model systems for studying the structure and development of highly adapted integumentary accessory organs—The role of the dermo-epidermal interface for the micro-architecture of complex epidermal structures. J Exp Zool 2003;298B:140–51.
- Pollitt CC. The anatomy and physiology of the suspensory apparatus of the distal phalanx. Vet Clin North Am Equine Pract 2010;26:29–49.
- MacFadden BJ. What's the use? Functional morphology of feeding and locomotion. Fossil horses: Systematics, paleobiology, and evolution of the family equidae.New York, NY: Cambridge University Press; 1992. p. 229–62.
- Fleckman P, Jaeger K, Silva KA, Sundberg JP. Comparative anatomy of mouse and human nail units. Anat Rec (Hoboken) 2013;296(3):521–32.
- Hood DM. The mechanisms and consequences of structural failure of the foot. Vet Clin North Am Equine Pract 1999;15(2):437–61.
- Collins SN, Van Eps AW, Kuwano A, Pollitt CC. The Lamellar Wedge. Vet Clin North Am Equine Pract 2010;26:179–95.
- Engiles JB, Galantino-Homer H, Boston R, McDonald D, Dishowitz M, Hankenson KD. Osteopathology in the equine distal phalanx associated with the development and progression of laminitis. J Vet Pathol 2015;52(5):928–44.
- Wattle O. Cytokeratins of the equine hoof wall, chestnut and skin: bio- and immunohisto-chemistry. Equine Vet J Suppl 1998;26:66–80.
- Wattle O. Cytokeratins of the stratum medium and stratum internum of the equine hoof wall in acute laminitis. Acta Vet Scand 2000;41(4):363–79.
- Carter RA, Shekk V, de Laat MA, Pollitt CC, Galantino-Homer HL. Novel keratins identified by quantitative proteomic analysis as the major cytoskeletal proteins of equine (Equus caballus) hoof lamellar tissue. J Anim Sci 2010. July 9;88(12):3843–55.
- Linardi R, Megee S, Mainardi S, Senoo M, Galantino-Homer H. Expression and localization of epithelial stem cell and differentiation markers in equine skin, eye and hoof. Vet Dermatol 2015;26(4):213–e47.
- Balmer P, Bauer A, Pujar S, McGarvey KM, Welle M, Galichet A. A curated catalog of canine and equine keratin genes. PLoS One 2017;12(8):e0180359.
- Tong X, Coulombe PA. A novel mouse type I intermediate filament gene, keratin 17n (K17n), exhibits preferred expression in nail tissue. J Invest Dermatol 2004;122:965–70.
- Hesse M, Zimek A, Weber K, Magin TM. Comprehensive analysis of keratin gene clusters in humans and rodents. European Journal of Cell Biology 2004;83:19–26.
- Zimek A, Weber K. The organization of the keratin I and II gene clusters in placental mammals and marsupials show a striking similarity. European Journal of Cell Biology 2006;85:83–9.
- Carter RA, Engiles JB, Megee SO, Senoo M, Galantino-Homer HL. Decreased expression of p63, a regulator of epidermal stem cells, in the chronic laminitic equine hoof. Equine Veterinary Journal 2011;43(5):543–51.
- Galantino-Homer H, Carter R, Megee S, Engiles J, Orsini J, Pollitt C. The Laminitis Discovery Database. J Equine Vet Sci 2010;30(2):101.
- Pollitt CC. Basement membrane pathology: a feature of acute equine laminitis. Equine Veterinary Journal 1996;28(1):38–46.
- Clark RK, Galantino-Homer H. Wheat Germ Agglutinin as a Counterstain for Immunofluorescence Studies of Equine Hoof Lamellae. Exp Dermatol 2014;23(9):677–8.
- Untergasser A, Cutcutache I, Koressaar T, Ye J, Faircloth BC, Remm M. Primer3—new capabilities and interfaces. Nucleic Acids Research 2012;40(15):e115.
- Wolenski FS, Layden MJ, Martindale MQ, Gilmore TD, Finnerty JR. Characterizing the spatiotemporal expression of RNAs and proteins in the starlet sea anemone Nematostella vectensis. Nat Protoc 2013;8:900–15.
- Wagner B, Hillegas JM, Babasyan S. Monoclonal antibodies to equine CD23 identify the low-affinity receptor for IgE on subpopulations of IgM+ and IgG1+ B-cells in horses. Vet Immunol Immunopathol 2012;146(2):125–34.
- Wagner B, Radbruch A, Rohwer J, Leibold W. Monoclonal anti-equine IgE antibodies with specificity for different epitopes on the immunoglobulin heavy chain of native IgE. Vet Immunol Immunopathol 2003;92(1–2):45–60.
- Schnabel CL, Wemette M, Babasyan S, Freer H, Baldwin C, Wagner B. C-C motif chemokine ligand (CCL) production in equine peripheral blood mononuclear cells identified by newly generated monoclonal antibodies. Vet Immunol Immunopathol 2018;204:28–39.
- Porter RM, Lunny DP, Ogden PH, Morley SM, McLean WH, Evans A. K15 expression implies lateral differentiation within stratified epithelial basal cells. Lab Invest 2000;80(11):1701–10.
- De Berker D, Wojnarowska F, Sviland L, Westgate GE, Dawber RPR, Leigh IM. Keratin expression in the normal nail unit: Markers of regional differentiation. Brit J Dermatol 2000;142:89–96.
- Daradka M, Pollitt CC. Epidermal cell proliferation in the equine hoof wall. Equine Veterinary Journal 2004;36:236–41.
- Linn SC, Mustonen AM, Silva KA, Kennedy VE, Sundberg BA, Bechtold LS. Nail abnormalities identified in an ageing study of 30 inbred mouse strains. Exp Dermatol 2019;28:383–90.
- Ehrlich F, Fischer H, Langbein L, Praetzel-Wunder S, Ebner B, Figlak K. Differential evolution of the epidermal keratin cytoskeleton in terrestrial and aquatic mammals. Mol Biol Evol 2018.
- Grosenbaugh DA, Hood DM. Keratin and associated proteins of the equine hoof wall. Am J Vet Res 1992;53(10):1859–63.
- Wade CM, Giulotto E, Sigurdsson S, Zoli M, Gnerre S, Imsland F. Genome sequence, comparative analysis, and population genetics of the domestic horse. Science 2009;326:865–7.
- Zhang G, Li C, Li Q, Li B, Larkin DM, Lee C. Comparative genomics reveals insights into avian genome evolution and adaptation. Science 2014;346(6215):1311–20.
- Wu P, Ng CS, Yan J, Lai Y-C, Chen C-K, Lai Y-T. Topographical mapping of α- and β-keratins on developing chicken skin integuments: Functional interaction and evolutionary perspectives. Proc Natl Acad Sci U S A 2015;E6770–E6779.
- Leise BS, Watts M, Roy S, Yilmaz S, Alder H, Belknap JK. Use of laser capture microdissection for the assessment of equine lamellar basal epithelial cell signalling in the early stages of laminitis. Equine Vet J 2015;47(4):478–88.
- Cassimeris L, Engiles JB, Galantino-Homer H. Detection of endoplasmic reticulum stress and the unfolded protein response in naturally-occurring endocrinopathic equine laminitis. BMC Vet Res 2019;15(1):24.
- Faleiros RR, Nuovo GJ, Belknap JK. Calprotectin in myeloid and epithelial cells of laminae from horses with black walnut extract-induced laminitis. J Vet Intern Med 2009;23(1):174–81.
- Strnad P, Paschke S, Jang KH, Ku NO. Keratins: markers and modulators of liver disease. Curr Opin Gastroenterol 2012;28(3):209–16.
- Karikoski NP, McGowan CM, Singer ER, Asplin KE, Tulamo R-M, Patterson-Kane JC. Pathology of natural cases of equine endocrinopathic laminitis associated with hyperinsulinemia. Vet Pathol 2014;Epub 17 Sep. pii: 0300985814549212.
- Ku NO, Strnad P, Bantel H, Omary MB. Keratins: Biomarkers and modulators of apoptotic and necrotic cell death in the liver. Hepatology 2016;64(3):966–76.
- Linder S, Olofsson MH, Herrmann R, Ulukaya E. Utilization of cytokeratin-based biomarkers for pharmacodynamic studies. Expert Rev Mol Diagn 2010;10(3):353–9.
Citations
This article has been cited 4 times.- Holthaus KB, Steinbinder J, Sachslehner AP, Eckhart L. Skin Appendage Proteins of Tetrapods: Building Blocks of Claws, Feathers, Hair and Other Cornified Epithelial Structures. Animals (Basel) 2025 Feb 6;15(3).
- Kalabusheva EP, Shtompel AS, Rippa AL, Ulianov SV, Razin SV, Vorotelyak EA. A Kaleidoscope of Keratin Gene Expression and the Mosaic of Its Regulatory Mechanisms. Int J Mol Sci 2023 Mar 15;24(6).
- Sundberg JP, Galantino-Homer H, Fairfield H, Ward-Bailey PF, Harris BS, Berry M, Pratt CH, Gott NE, Bechtold LS, Kaplan PR, Durbin-Johnson BP, Rocke DM, Rice RH. Witch Nails (Krt90whnl): A spontaneous mouse mutation affecting nail growth and development. PLoS One 2022;17(11):e0277284.
- Cassimeris L, Engiles JB, Galantino-Homer H. Interleukin-17A pathway target genes are upregulated in Equus caballus supporting limb laminitis. PLoS One 2020;15(12):e0232920.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists