Megan Mulholland1, Gabriel Jakobsson2, Yu Lei3, Lena Sundius2, Irena Ljungcrantz2, Sara Rattik2, Uwe J F Tietge4, Daniel Engelbertsen5. 1. Department of Clinical Sciences, Lund University, Skåne University Hospital, 20502, Malmö, Sweden. Electronic address: megan.mulholland@med.lu.se. 2. Department of Clinical Sciences, Lund University, Skåne University Hospital, 20502, Malmö, Sweden. 3. Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, S-14183, Stockholm, Sweden. 4. Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet, S-14183, Stockholm, Sweden; Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, SE-141 86, Stockholm, Sweden. 5. Department of Clinical Sciences, Lund University, Skåne University Hospital, 20502, Malmö, Sweden. Electronic address: daniel.engelbertsen@med.lu.se.
Abstract
BACKGROUND AND AIMS: The relationship between inflammation and lipid metabolism is complex and bidirectional. Lymphocyte-driven inflammation has been shown to modulate both atherosclerotic plaque development and cholesterol levels, but the mechanisms are incompletely understood. METHODS: The cardiometabolic effects of IL-2Rβγ signalling in atherosclerotic Apoe-/- mice were investigated by treatment with an agonistic IL-2Rβγ-targeting IL-2/anti-IL-2 complex or a monoclonal anti-CD122 (IL-2Rβ) blocking antibody. RESULTS: Administration of IL-2Rβγ agonistic IL-2/anti-IL-2 complexes to Apoe-/- mice augmented opposing arms of the adaptive immune system. Expansion of effector/memory T cells and increased levels of circulating pro-inflammatory cytokines were observed along with elevated levels of regulatory T cells and IL-10. Notably, IL-2/anti-IL-2 treatment did not affect plaque size but decreased levels of plasma cholesterol. The cholesterol lowering effect of IL-2Rβγ agonism was not affected by anti-CD8 or anti-NK1.1 depleting antibody treatment but was contingent on the presence of adaptive immunity. Expression of multiple liver X receptor (LXR)-related genes, including Pltp and Srebp1c in the liver, was decreased by IL-2/anti-IL-2 treatment. Although IL-2Rβγ agonism lowered cholesterol levels, blocking IL-2Rβγ signalling using an anti-CD122 monoclonal antibody did not impact cholesterol levels or plaque burden in Apoe-/- mice. CONCLUSIONS: Elevated IL-2Rβγ signalling results in activation of both inflammatory and regulatory lymphocytes with a net zero effect on atherosclerosis and decreased plasma cholesterol levels. Changes in cholesterol levels were associated with reductions in hepatic LXR-related gene expression. Further studies are needed to investigate the clinical significance of IL-2 mediated modulation of hepatic LXR signalling in inflammatory disorders.
BACKGROUND AND AIMS: The relationship between inflammation and lipid metabolism is complex and bidirectional. Lymphocyte-driven inflammation has been shown to modulate both atherosclerotic plaque development and cholesterol levels, but the mechanisms are incompletely understood. METHODS: The cardiometabolic effects of IL-2Rβγ signalling in atherosclerotic Apoe-/- mice were investigated by treatment with an agonistic IL-2Rβγ-targeting IL-2/anti-IL-2 complex or a monoclonal anti-CD122 (IL-2Rβ) blocking antibody. RESULTS: Administration of IL-2Rβγ agonistic IL-2/anti-IL-2 complexes to Apoe-/- mice augmented opposing arms of the adaptive immune system. Expansion of effector/memory T cells and increased levels of circulating pro-inflammatory cytokines were observed along with elevated levels of regulatory T cells and IL-10. Notably, IL-2/anti-IL-2 treatment did not affect plaque size but decreased levels of plasma cholesterol. The cholesterol lowering effect of IL-2Rβγ agonism was not affected by anti-CD8 or anti-NK1.1 depleting antibody treatment but was contingent on the presence of adaptive immunity. Expression of multiple liver X receptor (LXR)-related genes, including Pltp and Srebp1c in the liver, was decreased by IL-2/anti-IL-2 treatment. Although IL-2Rβγ agonism lowered cholesterol levels, blocking IL-2Rβγ signalling using an anti-CD122 monoclonal antibody did not impact cholesterol levels or plaque burden in Apoe-/- mice. CONCLUSIONS: Elevated IL-2Rβγ signalling results in activation of both inflammatory and regulatory lymphocytes with a net zero effect on atherosclerosis and decreased plasma cholesterol levels. Changes in cholesterol levels were associated with reductions in hepatic LXR-related gene expression. Further studies are needed to investigate the clinical significance of IL-2 mediated modulation of hepatic LXR signalling in inflammatory disorders.