Supplementary Material for: Knock-Out of β-Glucosidase 2 Has No Influence on Dextran Sulfate Sodium-Induced Colitis

Background/Aims: The non-lysosomal glucosylceramidase, β-glucosidase (Gba2), hydrolyzes glucosylceramide to glucose and ceramide (Cer). Cer is a potent second-messenger lipid that plays an important role in signaling cascades involved in apoptosis. The aim of this study was to investigate whether Gba2 knock-out (Gba2^–/–) affects the extent of dextran sulfate sodium (DSS)-induced colitis in mice. Methods: Acute colitis was induced in wild-type (WT) and Gba2^–/– mice by administration of 2% DSS in drinking water. After 7 days, mice underwent colonoscopy and were sacrificed. Results: Both DSS-treated WT (n = 10) and Gba2^–/– (n = 12) mice showed elevated histological and endoscopic scores compared to respective H₂O controls (n = 9 each). However, no significant differences between the DSS groups were detected. Flow cytometric analysis of propidium iodide staining, cleavage of caspases-3 and -8, indicative for apoptosis, as well as Cer levels were not altered in DSS-treated WT or Gba2^–/– mice. Gba2^–/– resulted in slightly decreased expression of glucocerebrosidase (Gba1) as well as in upregulation of proteins being involved in cellular regeneration, such as STAT3 (signal transducer and activator of transcription), JNK and iNOS, upon DSS treatment. Conclusion: We demonstrate that Gba2^–/– does not affect the extent of DSS-induced inflammation in mice, however, it might be involved in tissue regeneration in response to toxic agents.