Connexins are the subunit proteins of gap junctions, which allow the exchange of ions, second messengers and small metabolites between adjacent cells through intercellular channels. In addition, connexins can form functional hemichannels in non-junctional membranes. Mutations in connexin genes cause a variety of human diseases, including deafness and skin disorders. For example, mutations in connexin26 (Cx26, or GJB2) cause nonsyndromic deafness, or syndromic deafness associated with a variety of skin disorders including palmoplantar keratoderma (PPK), keratitis- ichthyosis-deafness syndrome (KID), and Vohwinkel syndrome (VS). The Cx26 mutations causing skin diseases and deafness are all single amino acid changes, and the mechanism(s) whereby they lead to skin pathology are unknown. Since nonsyndromic deafness is predominantly a loss of function disorder, it follows that the syndromic mutants may show an alteration, or gain, of function to cause skin disease. In this proposal, we seek to precisely define the functional consequences of Cx26 mutations that cause skin disease in humans. In addition, we seek to develop animal models that replicate human skin disorders caused by connexin mutations and use them to explore potential therapeutic intervention strategies. We propose first to examine the functional properties of dominant Cx26 mutations that cause skin disease. Second, we will generate transgenic mouse models of human skin disease and characterize the progression of epidermal pathology. Third, we will use pharmacological inhibition and/or antisense mediated knockdown in transfected cell systems and transgenic animals to inhibit mutant connexin activity. These studies will provided insights into how mutations alter the functional activity of Cx26 leading to skin disease, if these novel functions change epidermal homeostasis in animal models, and whether specific inhibition of the mutant proteins will show promise as a potential therapeutic strategy.

Public Health Relevance

Mutations in connexin genes cause a broad spectrum of human health problems. In the case of Cx26, functional studies have revealed much about deafness causing mutations, but very little is known about the functional consequences of Cx26 mutations that cause skin disease. The proposed studies will show how mutations alter the functional activity of Cx26 leading to skin disease, whether these novel functions cause skin disease in experimental animals, and if specific inhibition of the mutant proteins will show promise as a possible therapeutic strategy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR059505-04
Application #
8438425
Study Section
Special Emphasis Panel (ZRG1-MOSS-C (02))
Program Officer
Baker, Carl
Project Start
2010-04-01
Project End
2015-02-28
Budget Start
2013-03-01
Budget End
2014-02-28
Support Year
4
Fiscal Year
2013
Total Cost
$320,405
Indirect Cost
$105,268
Name
State University New York Stony Brook
Department
Physiology
Type
Schools of Medicine
DUNS #
804878247
City
Stony Brook
State
NY
Country
United States
Zip Code
11794