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Hyperglycemia and Not Hyperinsulinemia Mediates Diabetes-Induced Memory Cd8 T Cell Dysfunction
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posted on 2022-01-19, 16:41 authored by Inga Kavazović, Mia Krapić, Ammarina Beumer-Chuwonpad, Bojan Polić, Tamara Turk Wensveen, Niels A. Lemmermann, Klaas P.J.M. van Gisbergen, Felix M. WensveenDiabetes mellitus type 2 (T2D) causes an
increased risk of morbidity and mortality in response to viral infection. T2D
is characterized by hyperglycemia and is typically associated with insulin
resistance and compensatory hyperinsulinemia. CD8 T cells express the insulin
receptor and previously we have shown that insulin is able to directly modulate
effector CD8 T cell function. We therefore hypothesized memory CD8 T cell
responsiveness in context of T2D is negatively impacted by hyperinsulinemia or
hyperglycemia. Using a mouse model for T2D we could show that memory CD8 T cell
function was significantly reduced in response to re-challenge by viral
infection or with melanoma cells. Basal insulin injection of mice increased
GLUT-1 expression and glucose uptake in memory CD8 T cell precursors early
after infection, which was prevented when these cells were deficient for the
insulin receptor. However, neither insulin injection, nor insulin receptor
deficiency resulted in a difference in metabolism, memory formation, cytokine
production or recall responses of memory CD8 T cells compared to controls.
Importantly, in context of obesity, insulin receptor deficiency on CD8 T cells
did not affect the functional capacity of memory CD8 T cells. In contrast, we
could show in vitro and in vivo that hyperglycemia significantly impairs the
antiviral capacity of memory CD8 T cells. Our findings indicate that obesity
impairs the memory CD8 T cell response against viral infection and cancer
through the detrimental effects of hyperglycemia rather than hyperinsulinemia.