CD38 controls IL-2 production in CD4 T cells

CD38 has emerged as a potential therapeutic target for patients with systemic lupus erythematosus (SLE) but it is not known whether CD38 alters CD4+ T cell function. Using primary human T cells and CD38-sufficient and -deficient Jurkat T cells, we demonstrate that CD38 shifts the T cell lipid profile of gangliosides from GM3 to GM2 by upregulating B4GALNT1 in a Sirtuin 1-dependent manner. Enhanced expression of GM2 causes ER stress by enhancing Ca2+ flux through the PLC_1-IP3 pathway. Interestingly, correction of the calcium overload by an IP3 receptor inhibitor, but not by a store-operated calcium entry (SOCE) inhibitor, improves IL-2 production by CD4+ T cells in SLE. This study demonstrates that CD38 affects calcium homeostasis in CD4+ T cells by controlling cell membrane lipid composition that results in suppressed IL-2 production. CD38 inhibition with biologics or small drugs should be expected to benefit patients with SLE. Total RNA was extracted from JurkatControl and JurkatCD38KO using the RNeasy mini kit (QIAGEN) and submitted for RNA sequencing to the Molecular Biology Core Facilities at the Dana-Farber Cancer Institute (DFCI). Libraries were prepared using Illumina TruSeq Stranded mRNA sample preparation kits according to the manufacturer’s protocols. Samples were sequenced on an Illumina NextSeq500 run with single-end 75-bp reads. Data analyses were performed using the VIPER pipeline by the DFCI Core.