Nicastrin haploinsufficiency alters expression of type-I interferon-stimulated genes in two immortalized human cell lines
A.BackgroundHidradenitis suppurativa (HS) is a chronic skin disease. The symptoms can be severe, and include intensely painful nodules and abscesses in apocrine-gland rich inverse skin, such as the buttocks, under the arms, and the groin. Autosomal dominant forms of HS exist, but are rare. Some of these kindred have heterozygous loss-of-function rare variants in the {gamma}-secretase complex component nicastrin (NCSTN).\n\nObjectivesWe wanted to know what effect NCSTN haploinsufficiency has on human keratinocytes to assess potential mechanisms for lesion development.\n\nMethodsWe knocked down nicastrin using an shRNA construct in both a keratinocyte cell line (HEK001) and an embryonic kidney cell line (HEK293). We assessed differential gene expression using RNA microarray. We also generated a NCSTN heterozygous deletion in the HEK293 line using CRISPR/Cas9 genome-editing and assessed NFKB activity in this line using a luciferase reporter.\n\nResultsThe keratinocyte NCSTN knockdown cell line demonstrated significantly increased expression of genes related to the type-I interferon response pathway when compared to controls. Both HEK001 and HEK293 knockdowns demonstrated evidence for altered growth. We observed a small, but significant increase in NFKB signaling in response to TNF treatment a HEK293 line genome-edited for reduced NCSTN.\n\nConclusionsOur data suggest a role for increased keratinocyte inflammatory responsiveness in familial HS. Confirming this phenotype, and characterizing additional effects in different cell types, will require study beyond cell lines in primary cells and tissues.