Harlequin Ichthyosis Thickened skin plates and ABCA 12
Harlequin Ichthyosis Thickened skin plates and ABCA 12 Erin Seablom
What is Harlequin Ichthyosis? 2 2
What are the symptoms? Hyperkeratosis of epidermis Impaired barrier function 3 Abnormal Lamellar Granules 3
What are Lamellar Granules (LG)? WT healthy LG Normal keratin shedding, WT skin HI abnormal LG Lessened keratin shedding, HI skin Lipid containing bodies that transport molecules in the epidermis to catalyze keratin shedding 4 4
What are Lamellar Granules (LG)? WT healthy LG Normal keratin shedding, WT skin HI abnormal LG Lessened keratin shedding, HI skin Lipid containing bodies that transport molecules in the epidermis to catalyze keratin shedding 5 4
The ABCA 12 gene is mutated in Harlequin Ichthyosis ABC 2 mem 3 AAA 2277 AA Cellular Component Molecular Function Biological Process Binds and utilizes ATP Formation of the epidermis Lipid transfer to Lamellar Granules 6 5
The ABCA 12 gene is mutated in Harlequin Ichthyosis ABC 2 mem 3 AAA 2277 AA Cellular Component Molecular Function Biological Process Binds and utilizes ATP Formation of the epidermis Lipid transfer to Lamellar Granules 7 5
The ABCA 12 gene is mutated in Harlequin Ichthyosis ABC 2 mem 3 AAA 2277 AA Cellular Component Molecular Function Biological Process Binds and utilizes ATP Formation of the epidermis Lipid transfer to Lamellar Granules 8 5
The ABCA 12 gene is mutated in Harlequin Ichthyosis ABC 2 mem 3 AAA 2277 AA Cellular Component Molecular Function Biological Process Formation of the epidermis Binds and utilizes ATP 9 Lipid transfer to Lamellar Granules 5
ABCA 12 is a conserved protein involved in lipid transport ABC 2 mem 3 AAA 2277 AA 2595 AA 1755 AA 1807 AA 10 6
ABCA 12 is an ancient gene C. elegans Drosophila Zebra fish Saltwater crocodile Painted turtle Burmese python Mouse Dog Chimpanzee Human 11 7
Skin formation and lipid transport gene ontology groups interact Human Mouse Skin development Skin barrier establishment Epidermis development Small molecule transport Lipid transport 12 9
Skin formation and lipid transport gene ontology groups interact Human Mouse Skin development Skin barrier establishment Epidermis development Small molecule transport Lipid transport 13 9
GAP: How does ABCA 12 mediate lipid transport and lamellar granule formation in the epidermis? ABCA 12 Lessened keratin shedding ABCA 12 ? ? WT Normal keratin shedding, WT skin 14 10
GAP: How does ABCA 12 mediate lipid transport and lamellar granule formation in the epidermis? ABCA 12 Lessened keratin shedding ABCA 12 ? ? WT Normal keratin shedding, WT skin 15 10
Why are mice excellent models to study lipid transport and lamellar granule formation in the skin? Hyperkeratosis of epidermis Impaired barrier function 16 Abnormal Lamellar Granules 8
Why are mice excellent models to study lipid transport and lamellar granule formation in the skin? Hyperkeratosis of epidermis Impaired barrier function 17 Abnormal Lamellar Granules 8
Why are mice excellent models to study lipid transport and lamellar granule formation in the skin? Hyperkeratosis of epidermis Impaired barrier function 18 Abnormal Lamellar Granules 8
Why are mice excellent models to study lipid transport and lamellar granule formation in the skin? Hyperkeratosis of epidermis Impaired barrier function 19 Abnormal Lamellar Granules 8
Goal: Determine role of ABCA 12 in lamellar granule formation in the epidermis AIM 1 Identify amino acids in ABCA 12 necessary for lamellar granule formation in skin AIM 2 Identify differentially expressed genes important for lamellar granule formation in skin 20 AIM 3 Identify proteins important for lamellar granule formation in the skin and quantify expression 11
AIM 1 a: Identify amino acids in ABCA 12 important for lipid transport and lamellar granule formation in the skin AAA 21 12
AIM 1 a: Identify amino acids in ABCA 12 important for lipid transport and lamellar granule formation in the skin AAA A B A: amino acid conserved in all organisms B: amino acid conserved half but varying in non-mammals C: amino acid conserved only 22 in mammals C 12
KO conserved AAs that are important for LG formation and lipid transport in the skin AIM 1 b: A KO AA KO Stem cells B KO A B C C KO Hypothesis: KO of AAs of interest will lead to impaired lipid transport and lamellar granule formation 23 13
KO conserved AAs that are important for LG formation and lipid transport in the skin AIM 1 b: A KO AA KO Stem cells B KO A B C C KO Hypothesis: KO of AAs of interest will lead to impaired lipid transport and lamellar granule formation 24 13
KO conserved AAs that are important for LG formation and lipid transport in the skin AIM 1 b: A KO AA KO Stem cells B KO A B C C KO Hypothesis: KO of AAs of interest will lead to impaired lipid transport and lamellar granule formation 25 13
AIM 1 c: Assay for defects in lipid transport and lamellar granule formation in the skin of AA KO mutants Thickened Epidermis WT AA KO Impaired Barrier Function WT Abnormal Lamellar Granules AA KO WT 26 AA KO 14
AIM 2 a: Identify differentially expressed genes important for LG formation and lipid transport RNA Seq 15
AIM 2 b: Perform RNA Seq to gather gene expression data RNA Seq 15
AIM 2 c: Organize genes by GO and examine expression levels Normal GO Terms WT AA KO A AA KO B AA KO C Lipid Transport Epidermis Formation Skin Barrier Establishment Abnormal Hypothesis: Genes in mutant mice will have abnormal expression in lipid formation and lamellar granules compared to wild-type mice 16
AIM 3 a: Identify other protein interactions associated with ABCA 12, in lipid transport and LG formation in the skin using Bio ID 18
AIM 3 b: Quantify proteins associated with lipid transport and lamellar granule formation 31 19
AIM 3 b: Quantify proteins associated with lipid transport and lamellar granule formation 32 19
AIM 3 c: Categorize proteins associated with ABCA 12 with gene ontology Hypothesis: Proteins involved in lipid transport and lamellar granule formation will be more abundant in WT mice than in mutant mice 33 20
Conclusions HI is skin disorder caused by mutations in ABCA 12, leading to impaired lipid transport and lamellar granule formation ABCA 12 mutant mice will have differed gene expression than WT mice ABCA 12 interacts with other proteins that may be important for lipid transport and lamellar granule formation 34 21
Future Studies? 35 22
References [1] Harlequin ichthyosis. (2008, January). Retrieved from https: //ghr. nlm. nih. gov/condition/harlequinichthyosis [2] Harlequin ichthyosis. Retrieved from https: //rarediseases. info. nih. gov/diseases/6568/harlequinichthyosis 36 23
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