Skin inflammation and impaired adipogenesis in a mouse model of acid ceramidase deficiency

Abstract

Acid ceramidase catalyzes the degradation of ceramide into sphingosine and a free fatty acid. Acid ceramidase deficiency results in lipid accumulation in many tissues and leads to the development of Farber disease (FD). Typical manifestations of classical FD include formation of subcutaneous nodules and joint contractures as well as the development of a hoarse voice. Healthy skin depends on a unique lipid profile to form a barrier that confers protection from pathogens, prevents excessive water loss, and mediates cell-cell communication. Ceramides comprise $50% of total epidermis lipids and regulate cutaneous homeostasis and inflammation. Abnormal skin development including visual skin lesions has been reported in FD patients, but a detailed study of FD skin has not been performed. We conducted a pathophysiological study of the skin in our mouse model of FD. We observed altered lipid composition in FD skin dominated by accumulation of all studied ceramide species and buildup of abnormal storage structures affecting mainly the dermis. A deficiency of acid ceramidase activity also led to the activation of inflammatory IL-6/JAK/signal transducer and activator of transcription 3 and noncanonical NF-κB signaling pathways. Last, we report reduced proliferation of FD mouse fibroblasts and adipose-derived stem/stromal cells (ASC) along with impaired differentiation of ASCs into mature adipocytes.

Adiponectin overexpression improves metabolic abnormalities caused by acid ceramidase deficiency but does not prolong lifespan in a mouse model of Farber Disease

“…We studied mice with a missense mutation in ASAH1 (ASAH1 P361R/P361R ) that is analogous to a mutation identified in Farber Disease patients (NM_177924.5( ASAH1 ):c.1085C > G (p.Pro362Arg)) [ 61 ]. These mice reach maximum weight at 5 weeks, exhibit progressive growth retardation, accumulate inflammatory markers in tissues, show ceramide accumulation in blood, tissues, and skin, have a near complete loss of hypodermal adipose tissue, have stiff neck skin, and display sex-specific pathologies (e.g., small ovaries or penile prolapse) [ 61 , 62 ]. Further, these mice only survive between 7 and 13 weeks [ 61 ].…”