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PloS one2019; 14(9); e0219234; doi: 10.1371/journal.pone.0219234

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
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Summary

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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

ISSN: 1932-6203
NlmUniqueID: 101285081
Country: United States
Language: English
Volume: 14
Issue: 9
Pages: e0219234

Researcher Affiliations

Armstrong, Caitlin
  • Department of Clinical Studies, New Bolton Center, University of Pennsylvania, School of Veterinary Medicine, Kennett Square, Pennsylvania, United States of America.
Cassimeris, Lynne
  • Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
Da Silva Santos, Claire
  • Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
Micoogullari, Yagmur
  • Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
Wagner, Bettina
  • Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America.
Babasyan, Susanna
  • Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America.
Brooks, Samantha
  • Department of Animal Sciences and University of Florida Genetics institute, University of Florida, Gainesville, Florida, United States of America.
Galantino-Homer, Hannah
  • 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
  1. 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.
    doi: 10.1083/jcb.200603161pmc: PMC2064177pubmed: 16831889google scholar: lookup
  2. Bragulla HH, Homberger DG. Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia. J Anatomy 2009;214:516–59.
    pmc: PMC2736122pubmed: 19422428
  3. 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.
    doi: 10.1073/pnas.1313491110pmc: PMC3831947pubmed: 24167246google scholar: lookup
  4. Homberg M, Magin TM. Beyond expectations: novel insights into epidermal keratin function and regulation. Int Rev Cell Mol Biol 2014;311:265–306.
  5. Lane EB, McLean WH. Keratins and skin disorders. J Pathol 2004;204(4):355–66.
    doi: 10.1002/path.1643pubmed: 15495218google scholar: lookup
  6. 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.
    pubmed: 17719747
  7. 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.
  8. Jin L, Wang G. Keratin 17: a critical player in the pathogenesis of psoriasis. Med Res Rev 2014;34(2):438–54.
    doi: 10.1002/med.21291pubmed: 23722817google scholar: lookup
  9. Fuchs E, Weber K. Intermediate filaments: Structure, dynamics, function, and disease. Annu Rev Biochem 1994;63:345–82.
  10. Moll R, Divo M, Langbein L. The human keratins: biology and pathology. Histochem Cell Biol 2008;129:705–33.
    doi: 10.1007/s00418-008-0435-6pmc: PMC2386534pubmed: 18461349google scholar: lookup
  11. Lee CH, Coulombe PA. Self-organization of keratin intermediate filaments into cross-linked networks. J Cell Biol 2009;186(3):409–21.
    doi: 10.1083/jcb.200810196pmc: PMC2728393pubmed: 19651890google scholar: lookup
  12. 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.
  13. 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.
  14. 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.
    pubmed: 12949774
  15. Pollitt CC. The anatomy and physiology of the suspensory apparatus of the distal phalanx. Vet Clin North Am Equine Pract 2010;26:29–49.
    doi: 10.1016/j.cveq.2010.01.005pubmed: 20381734google scholar: lookup
  16. 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.
  17. Fleckman P, Jaeger K, Silva KA, Sundberg JP. Comparative anatomy of mouse and human nail units. Anat Rec (Hoboken) 2013;296(3):521–32.
    pmc: PMC3579226pubmed: 23408541
  18. Hood DM. The mechanisms and consequences of structural failure of the foot. Vet Clin North Am Equine Pract 1999;15(2):437–61.
    pubmed: 10472121
  19. Collins SN, Van Eps AW, Kuwano A, Pollitt CC. The Lamellar Wedge. Vet Clin North Am Equine Pract 2010;26:179–95.
    doi: 10.1016/j.cveq.2010.01.004pubmed: 20381746google scholar: lookup
  20. 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.
    pubmed: 26063172
  21. Wattle O. Cytokeratins of the equine hoof wall, chestnut and skin: bio- and immunohisto-chemistry. Equine Vet J Suppl 1998;26:66–80.
    pubmed: 9932096
  22. 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.
    pmc: PMC7996434pubmed: 11234970
  23. 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.
    doi: 10.2527/jas.2010-2964pubmed: 20622188google scholar: lookup
  24. 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.
    doi: 10.1111/vde.12214pmc: PMC4506204pubmed: 25963063google scholar: lookup
  25. 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.
  26. 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.
  27. 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.
    doi: 10.1078/0171-9335-00354pubmed: 15085952google scholar: lookup
  28. 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.
    doi: 10.1016/j.ejcb.2005.10.001pubmed: 16439307google scholar: lookup
  29. 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.
  30. 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.
  31. Pollitt CC. Basement membrane pathology: a feature of acute equine laminitis. Equine Veterinary Journal 1996;28(1):38–46.
  32. 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.
    doi: 10.1111/exd.12495pubmed: 25040657google scholar: lookup
  33. Untergasser A, Cutcutache I, Koressaar T, Ye J, Faircloth BC, Remm M. Primer3—new capabilities and interfaces. Nucleic Acids Research 2012;40(15):e115.
    doi: 10.1093/nar/gks596pmc: PMC3424584pubmed: 22730293google scholar: lookup
  34. 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.
    doi: 10.1038/nprot.2013.014pmc: PMC4792812pubmed: 23579779google scholar: lookup
  35. 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.
    doi: 10.1016/j.vetimm.2012.02.007pubmed: 22405681google scholar: lookup
  36. 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.
    doi: 10.1016/s0165-2427(03)00007-2pubmed: 12628763google scholar: lookup
  37. 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.
    doi: 10.1016/j.vetimm.2018.09.003pubmed: 30596378google scholar: lookup
  38. 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.
    pubmed: 11092530
  39. 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.
    pubmed: 10651700
  40. Daradka M, Pollitt CC. Epidermal cell proliferation in the equine hoof wall. Equine Veterinary Journal 2004;36:236–41.
    doi: 10.2746/0425164044877198pubmed: 15147131google scholar: lookup
  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.
    doi: 10.1111/exd.13759pmc: PMC6360140pubmed: 30074290google scholar: lookup
  42. 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.
    pmc: PMC6367960pubmed: 30517738
  43. Grosenbaugh DA, Hood DM. Keratin and associated proteins of the equine hoof wall. Am J Vet Res 1992;53(10):1859–63.
    pubmed: 1280927
  44. 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.
    doi: 10.1126/science.1178158pmc: PMC3785132pubmed: 19892987google scholar: lookup
  45. 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.
    doi: 10.1126/science.1251385pmc: PMC4390078pubmed: 25504712google scholar: lookup
  46. 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.
    doi: 10.1073/pnas.1520566112pmc: PMC4679038pubmed: 26598683google scholar: lookup
  47. 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.
    doi: 10.1111/evj.12283pmc: PMC4771185pubmed: 24750316google scholar: lookup
  48. 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.
    doi: 10.1186/s12917-018-1748-xpmc: PMC6327420pubmed: 30630474google scholar: lookup
  49. 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.
  50. Strnad P, Paschke S, Jang KH, Ku NO. Keratins: markers and modulators of liver disease. Curr Opin Gastroenterol 2012;28(3):209–16.
    doi: 10.1097/MOG.0b013e3283525cb8pubmed: 22450891google scholar: lookup
  51. 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.
    pubmed: 25232034
  52. 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.
    doi: 10.1002/hep.28493pmc: PMC4977204pubmed: 26853542google scholar: lookup
  53. 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.
    doi: 10.1586/erm.10.14pubmed: 20370591google scholar: lookup

Citations

This article has been cited 4 times.
  1. 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).
    doi: 10.3390/ani15030457pubmed: 39943227google scholar: lookup
  2. 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).
    doi: 10.3390/ijms24065603pubmed: 36982676google scholar: lookup
  3. 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.
    doi: 10.1371/journal.pone.0277284pubmed: 36374931google scholar: lookup
  4. 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.
    doi: 10.1371/journal.pone.0232920pubmed: 33301461google scholar: lookup