John R. Edminister MD

Assistant Professor/Director of the Center for Translational Dermatology Research Wake Forest University Health Sciences

Award: $15,000

OBJECTIVE:

Investigate how altering calcium receptor (CaSR) function with potential new drug therapies affects mutant proteins (SERCA2 and SPCA1) and cellular health in models of the debilitating genetic blistering diseases, Darier Disease and Hailey Hailey Disease

AIMS:

Aim 1: Establish and compare the degree of blistering of in vitro models of DD and HHD using reconstructed human
epidermis (RHE) with specific inhibitors of SERCA2 (Thapsigargin) and SPCA1 (1,3-thiazoles), respectively.
Aim 2: Measure the resistance to cell-cell fragmentation in DD and HHD models by the dispase dissociation assay.
Aim 3: Assess changes in subcellular calcium flux before and after CaSR modulation.

METHODS:

1. Establish disease models with reconstructed human epidermis
2. Morphometric analysis of intraepidermal blistering on RHE models
3. Quantify protein expression of calcium pumps, channels, and endoplasmic reticulum stress markers
4. Dispase dissociation assay
5. Measurement of mitochondrial calcium uptake
6. Measurement of Golgi calcium concentration
7. Measurement of ER and mitochondrial calcium release
8. Measurement of mitochondrial calcium retention capacity

RELEVANCE TO THE MISSION OF FIRST:

The proposed study is broadly important for all epidermal differentiation diseases (EDDs), formerly known as icthyoses. The CaSR signaling pathway is highly relevant to the entire ichthyosis field given the relationship between calcium metabolism and keratinocyte differentiation. This is best exemplified by exciting new findings in the syndromic steroid sulfatase EDD (STS-sEDD, formerly "X-linked ichthyosis"), where the defective steroid sulfatase enzyme causes increased CaSR expression and excessive calcium signaling that produces the pathologic hyperkeratinization; in this case, a calcilytic like encaleret is a putative pathway-targeted therapy that demands future investigation (reference 4). Indeed, CaSR signaling directly modulates the expression of numerous keratinolytic differentiation proteins such as K1, TGM1, and FLG – all of which have been implicated in various EDDs (references 5,6).

Researchers interested in funding Through FIRST'S Research Grant Program