Farber disease (FD) and spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) are ultra-rare lysosomal storage disorders caused by deficient acid ceramidase (ACDase) activity. Although both conditions are caused by mutations in the ASAH1 gene, clinical presentations differ considerably. FD patients usually die in childhood, while SMA-PME patients can live until adulthood. There is no treatment for FD or SMA-PME. Hematopoietic stem cell transplantation (HSCT) and gene therapy strategies for the treatment of ACDase deficiency are being investigated. We have previously generated and characterized mouse models of both FD and SMA-PME that recapitulate the symptoms described in patients. Here, we show that HSCT improves lifespan, behavior, hematopoietic system anomalies, and plasma cytokine levels and significantly reduces histiocytic infiltration and ceramide accumulation throughout the tissues investigated, including the CNS, in both models of ACDase-deficient mice. HSCT was also successful in preventing lesion development and significant demyelination of the spinal cord seen in SMA-PME mice. Importantly, we note that only early and generally pre-symptomatic treatment was effective, and kidney impairment was not improved in either model.

• Keywords
• Farber disease, HSCT, Lysosomal storage disorders, central nervous system, ceramides, spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME),
• MeSH
• Ceramides metabolism   MeSH
• Farber Lipogranulomatosis * therapy   genetics   MeSH
• Acid Ceramidase * genetics   metabolism   MeSH
• Humans MeSH
• Spinal Cord metabolism   pathology   MeSH
• Disease Models, Animal MeSH
• Myoclonic Epilepsies, Progressive genetics   therapy   metabolism   MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Hematopoietic Stem Cell Transplantation * methods   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Asah1 protein, mouse MeSH Browser
• Ceramides MeSH
• Acid Ceramidase * MeSH

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.

• Keywords
• Farber disease, acid ceramidase, adipogenesis, ceramides, macrophages, skin,
• MeSH
• Adipogenesis MeSH
• Ceramides metabolism   MeSH
• Farber Lipogranulomatosis * MeSH
• Acid Ceramidase genetics   MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Inflammation MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Ceramides MeSH
• Acid Ceramidase MeSH

Farber disease (FD) is a debilitating lysosomal storage disorder characterized by severe inflammation and neurodegeneration. FD is caused by mutations in the ASAH1 gene, resulting in deficient acid ceramidase (ACDase) activity. Patients with ACDase deficiency exhibit a broad clinical spectrum. In classic cases, patients develop hepatosplenomegaly, nervous system involvement, and childhood mortality. Ocular manifestations include decreased vision, a grayish appearance to the retina with a cherry red spot, and nystagmus. That said, the full effect of ACDase deficiency on the visual system has not been studied in detail. We previously developed a mouse model that is orthologous for a known patient mutation in Asah1 that recapitulates human FD. Herein, we report evidence of a severe ocular pathology in Asah1P361R/P361R mice. Asah1P361R/P361R mice exhibit progressive retinal and optic nerve pathology. Through noninvasive ocular imaging and histopathological analyses of these Asah1P361R/P361R animals, we revealed progressive inflammation, the presence of retinal dysplasia, and significant storage pathology in various cell types in both the retina and optic nerves. Lipidomic analyses of retinal tissues revealed an abnormal accumulation of ceramides and other sphingolipids. Electroretinograms and behavioral tests showed decreased retinal and visual responses. Taken together, these data suggest that ACDase deficiency leads to sphingolipid imbalance, inflammation, dysmorphic retinal and optic nerve pathology, and severe visual impairment.

• MeSH
• Ceramides genetics   metabolism   MeSH
• Farber Lipogranulomatosis * enzymology   genetics   pathology   MeSH
• Acid Ceramidase genetics   metabolism   MeSH
• Mutation, Missense * MeSH
• Disease Models, Animal MeSH
• Mice, Mutant Strains MeSH
• Mice MeSH
• Optic Nerve * enzymology   pathology   MeSH
• Vision Disorders * enzymology   genetics   pathology   MeSH
• Retina * enzymology   pathology   MeSH
• Sphingolipids genetics   metabolism   MeSH
• Amino Acid Substitution MeSH
• Inflammation enzymology   genetics   pathology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• Asah1 protein, mouse MeSH Browser
• Ceramides MeSH
• Acid Ceramidase MeSH
• Sphingolipids MeSH