Journal: The Journal of Biological Chemistry
Article Title: Acid ceramidase ASAH1 is a key regulator of epidermal ceramide levels and composition
doi: 10.1016/j.jbc.2026.111178
Figure Lengend Snippet: Ceramide class–specific activity of ASAH1. HEK 293T cells were transfected with either the pCE-puro 3× FLAG-4 vector or the pCE-puro ASAH1-3× FLAG plasmid. Culture supernatant was collected 48 h after transfection as the enzyme source. A , proteins were concentrated via precipitation with 5% trichloroacetic acid, followed by SDS-PAGE and immunoblotting using an anti-FLAG antibody. B , the indicated ceramide species (final concentration, 5 μM; 600 pmol) were incorporated into liposomes and incubated with the culture supernatant from the pCE-puro ASAH1-3× FLAG plasmid-transfected cells (containing 145 ng ASAH1-3× FLAG) or with supernatant from vector-transfected cells as a negative control. After incubation, lipids were extracted, and the resulting long-chain bases (ceramide degradation products) were quantified via LC–MS/MS. Values presented are mean + SD of the quantity of long-chain bases produced per minute by 1 μg of ASAH1-3× FLAG, expressed in picomoles (n = 3; ∗ p < 0.05; ∗∗ p < 0.01; Welch’s t test). HEK, human embryonic kidney cell line.
Article Snippet: A mixture of 60 μl of 5 mg/ml 1-palmitoyl-2-oleoyl- sn -glycero-3-phosphocholine (16:0/18:1 phosphatidylcholine; Avanti Research), dissolved in chloroform/methanol (1:1, v/v), and 40 μl of each ceramide species at 100 μM— N -palmitoyl- d - erythro -sphingosine (C16:0 NS; Avanti Research), N -lignoceroyl- d - erythro -sphingosine (C24:0 NS; Avanti Research), N -nervonoyl- d - erythro -sphingosine (C24:1 NS; Avanti Research), N -lignoceroyl- d - erythro -dihydrosphingosine (C24:0 NdS; Avanti Research), N -lignoceroyl- d - ribo -phytosphingosine (C24:0 NP; Avanti Research), N -lignoceroyl-6-( R )-hydroxysphingosine (C24:0 NH; Avanti Research), N -(2'-( R )-hydroxylignoceroyl)- d - erythro -sphingosine (C24:0 AS; Avanti Research), N -(2'-( R )-hydroxylignoceroyl)- d - ribo -phytosphingosine (C24:0 AP; Avanti Research), N -(30-linoleoyloxy-triacontanoyl)- d - erythro -sphingosine (C30:0 EOS; Cayman Chemical), and N -ω-hydroxytriacontanoyl- d - erythro -sphingosine (C30:0 OS; Cayman Chemical)—was combined and dried.
Techniques: Activity Assay, Transfection, Plasmid Preparation, SDS Page, Western Blot, Concentration Assay, Liposomes, Incubation, Negative Control, Liquid Chromatography with Mass Spectroscopy, Produced