Adoptive Transfer of Ceramide Synthase 6 Deficient Splenocytes Reduces the Development of Colitis

Abstract

Sphingolipids regulate critical cellular processes including inflammation. Ceramide, which serves a central role in sphingolipid metabolism, is generated by six ceramide synthases (CerS) that differ in substrate specificity. CerS6 preferentially generates C16-ceramide and its mRNA is highly expressed in immune tissues. In this study we analyzed how deficiency of CerS6 impacts on the development of colitis using an adoptive transfer model. Adoptive transfer of CerS6-deficient splenocytes, which have significantly decreased levels of C16-ceramide, showed that CerS6-deficiency protected against the development of colitis. However, adoptively transferred cells isolated from the lamina propria of the large intestine from wild type or CerS6-deficient groups showed no differences in the percentages of immune-suppressive regulatory T cells, pro-inflammatory Th17 cells, or their ability to express IL-17. In vitro polarization of wild type or CerS6-deficient splenocytes also revealed no defects in the development of T cell subsets. Our data suggest that protection from colitis following adoptive transfer of CerS6-deficient splenocytes maybe related to their ability to migrate and proliferate in vivo rather than subset development or cytokine expression.

Advances in determining signaling mechanisms of ceramide and role in disease

“…Interestingly, this regulation appears to be cell type specific, as decreasing C16ceramide in CerS6 KO T-lymphocytes was found to protect against colitis development in an adoptive transfer model in recombination-activating gene 1-deficient mice. This protection may be due in part to a reduction in the ability of T-lymphocytes to migrate; however, it may also be due to decreased clonal expansion (8). Based on these findings it is possible that ceramide accumulation at the plasma membrane may differentially affect the activation of signaling pathways necessary for migration based on receptor availability in each cell type.…”

“…Ceramide-mediated clustering of Fas receptor (CD95) at the plasma membrane was found to be essential for formation of death-inducing signaling complex and subsequent caspase activation (6). Ceramides have also been proposed to influence membrane fluidity, which has been suggested to play a role in regulating cell migration (7,8). The effects of ceramide on membrane fluidity are complex and depend on acyl chain length (9), saturation (10), and ratio of long chain and very-long chain species present in the membrane (11,12).…”

Ceramide Synthase 6 Deficiency Enhances Inflammation in the DSS model of Colitis

“…MALDI imaging mass spectrometry (IMS) is a powerful tool to analyze the distribution of proteins and other molecules including sphingolipids in tissue sections in situ 16 , 17 . CerS6-deficient mice have significantly reduced C 16 -sphingolipids 11 , 15 . This reduced level of C 16 -sphingolipids was also observed in mice exposed to DSS (Fig.…”

“…1b ). This result was unexpected, since CerS6-deficient mice are protected from development of colitis in the adoptive transfer model 12 , 15 . C57BL/6 mice are highly susceptible to DSS colitis, thus weight loss may occur at the maximal rate masking differences in disease progression 20 .…”

“…These opposing consequences of CerS6-deficiency across models underscore the complexity of sphingolipid signaling. Recently, adoptive transfer of CerS6-deficient naïve CD4 + T cells was shown to protect mice from colitis 12 , 15 . In this study, we further elucidate the role of CerS6 in DSS-induced colitis, which is independent of T lymphocytes.…”