John P Sundberg

Publications (2)7.79 Total impact

• Article: Comparative anatomy of mouse and human nail units.

  Philip Fleckman, Karin Jaeger, Kathleen A Silva, John P Sundberg
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  ABSTRACT: Recent studies of mice with hair defects have resulted in major contributions to the understanding of hair disorders. To use mouse models as a tool to study nail diseases, a basic understanding of the similarities and differences between the human and mouse nail unit is required. In this study we compare the human and mouse nail unit at the macroscopic and microscopic level and use immunohistochemistry to determine the keratin expression patterns in the mouse nail unit. Both species have a proximal nail fold, cuticle, nail matrix, nail bed, nail plate, and hyponychium. Distinguishing features are the shape of the nail and the presence of an extended hyponychium in the mouse. Expression patterns of most keratins are similar. These findings indicate that the mouse nail unit shares major characteristics with the human nail unit and overall represents a very similar structure, useful for the investigation of nail diseases and nail biology. Anat Rec, 296:521-532, 2013. © 2013 Wiley Periodicals, Inc.
  The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 03/2013; 296(3):521-32. · 1.47 Impact Factor
• Source

  Available from: Jiang Chen

  Article: Mice expressing a mutant Krt75 (K6hf) allele develop hair and nail defects resembling pachyonychia congenita.

  Jiang Chen, Karin Jaeger, Zhining Den, Peter J Koch, John P Sundberg, Dennis R Roop
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  ABSTRACT: KRT75 (formerly known as K6hf) is one of the isoforms of the keratin 6 (KRT6) family located within the type II cytokeratin gene cluster on chromosome 12 of humans and chromosome 15 of mice. KRT75 is expressed in the companion layer and upper germinative matrix region of the hair follicle, the medulla of the hair shaft, and in epithelia of the nail bed. Dominant mutations in members of the KRT6 family, such as in KRT6A and KRT6B cause pachyonychia congenita (PC) -1 and -2, respectively. To determine the function of KRT75 in skin appendages, we introduced a dominant mutation into a highly conserved residue in the helix initiation peptide of Krt75. Mice expressing this mutant form of Krt75 developed hair and nail defects resembling PC. This mouse model provides in vivo evidence for the critical roles played by Krt75 in maintaining hair shaft and nail integrity. Furthermore, the phenotypes observed in our mutant Krt75 mice suggest that KRT75 may be a candidate gene for screening PC patients who do not exhibit obvious mutations in KRT6A, KRT6B, KRT16, or KRT17, especially those with extensive hair involvement.
  Journal of Investigative Dermatology 03/2008; 128(2):270-9. · 6.31 Impact Factor