Human lymphocytes mobilized with exercise have an anti-tumor transcriptomic profile and exert enhanced graft-versus-leukemia effects in xenogeneic mice

BackgroundEvery bout of exercise mobilizes and redistributes large numbers of effector lymphocytes with a cytotoxic and tissue migration phenotype. The frequent redistribution of these cells is purported to increase immune surveillance and play a mechanistic role in reducing cancer risk and slowing tumor progression in physically active cancer survivors. Our aim was to provide the first detailed single cell transcriptomic analysis of exercise-mobilized lymphocytes and test their effectiveness as a donor lymphocyte infusion (DLI) in xenogeneic mice engrafted with human leukemia.MethodsPeripheral blood mononuclear cells (PBMCs) were collected from healthy volunteers at rest and at the end of an acute bout of cycling exercise. Flow cytometry and single-cell RNA sequencing was performed to identify phenotypic and transcriptomic differences between resting and exercise-mobilized cells using a targeted gene expression panel curated for human immunology. PBMCs were injected into the tail vein of xenogeneic NSG-IL-15 mice and subsequently challenged with a luciferase tagged chronic myelogenous leukemia cell line (K562). Tumor growth (bioluminescence) and xenogeneic graft-versus-host disease (GvHD) were monitored bi-weekly for 40-days.ResultsExercise preferentially mobilized NK-cell, CD8+ T-cell and monocyte subtypes with a differentiated and effector phenotype, without significantly mobilizing CD4+ regulatory T-cells. Mobilized effector lymphocytes, particularly effector-memory CD8+ T-cells and NK-cells, displayed differentially expressed genes and enriched gene sets associated with anti-tumor activity, including cytotoxicity, migration/chemotaxis, antigen binding, cytokine responsiveness and alloreactivity (e.g. graft-versus-host/leukemia). Mice receiving exercise-mobilized PBMCs had lower tumor burden and higher overall survival (4.14E+08 photons/s and 47%, respectively) at day 40 compared to mice receiving resting PBMCs (12.1E+08 photons/s and 22%, respectively) from the same donors (p<0.05). Human immune cell engraftment was similar for resting and exercise-mobilized DLI. However, when compared to non-tumor bearing mice, K562 increased the expansion of NK-cell and CD3+/CD4-/CD8- T-cells in mice receiving exercise-mobilized but not resting lymphocytes, 1-2 weeks after DLI. No differences in GvHD or GvHD-free survival was observed between groups either with or without K562 challenge.ConclusionExercise in humans mobilizes effector lymphocytes with an anti-tumor transcriptomic profile and their use as DLI extends survival and enhances the graft-versus-leukemia (GvL) effect without exacerbating GvHD in human leukemia bearing xenogeneic mice. Exercise may serve as an effective and economical adjuvant to increase the GvL effects of allogeneic cell therapies without intensifying GvHD

The effects of normoxic endurance exercise on erythropoietin (EPO) production and the impact of selective β1 and non-selective β1 + β2 adrenergic receptor blockade

Purpose: Habitual endurance exercise results in increased erythropoiesis, which is primarily controlled by erythropoietin (EPO), yet studies demonstrating upregulation of EPO via a single bout of endurance exercise have been equivocal. This study compares the acute EPO response to 30 minutes of high versus 90 minutes of moderate intensity endurance exercise and whether that response can be upregulated via selective adrenergic receptor blockade. Methods: Using a counterbalanced, cross-over design, fifteen individuals (age 28±8) completed two bouts of running (30-minute, high intensity vs 90-minute, moderate intensity) matched for overall training stress. A separate cohort of fourteen individuals (age 31±6) completed three bouts of 30-minute high intensity cycling after ingesting the beta antagonist bisoprolol, nadolol or placebo. Venous blood was collected before, during and after exercise and EPO response assessed. Results: No detectable EPO response was observed during or after high intensity running, however in the moderate intensity trial EPO was significantly elevated at both during-exercise timepoints (+6.8% ± 2.3% at 15 minutes and +8.7% ± 2.2% at 60 minutes). No significant change in EPO was observed post-cycling or between βAR drug trials. Conclusion: Neither training mode (running or cycling), nor beta-blockade significantly influenced the EPO response to 30 minutes of high-intensity exercise, however 90 minutes of moderate-intensity running elevated EPO during exercise, returning to baseline immediately post exercise. This exercise dependent and transient elevation may explain equivocal data regarding the effect of exercise on serum EPO and allow prescription of exercise to maximize EPO response for both performance and clinical applications

Simulated microgravity disarms human NK-cells and inhibits anti-tumor cytotoxicity in vitro

Long-duration spaceflight impairs natural killer (NK) cell function, which could compromise immune surveillance in exploration class mission crew. To determine if microgravity can impair NK-cell function, we established a rotary cell culture system to expose human peripheral blood mononuclear cells to simulated microgravity (SMG) in vitro. We found that 12 h of SMG suppressed NK-cell cytotoxic activity (NKCA) by similar to 50% against K562, U266 and 721.221 tumor target cells when returned to the 1G environment. Mass cytometry was used to identify 37 individual markers associated with NK-cell activation, maturation and cytotoxicity, revealing that SMG causes reductions in NK-cell degranulation and effector cytokine production. Extended flow cytometry confirmed that SMG lowered NK cell perforin and granzyme b expression by 25% and 17% respectively, but did not affect the surface expression of various activating (NKG2D, NKp30) and inhibitory (NKG2A, KLRG1) receptors or the ability of NK-cells to conjugate with target cells. Flow cytometry further revealed that SMG impaired NK-cell degranulation (reduced CD107a+ expression) and suppressed TNF alpha and IFN gamma secretion in response to stimulation with K562 target cells. These findings indicate that SMG 'disarms' human NK-cells of cytolytic granules and impairs NKCA against a range of tumor target cells in vitro. Exposure to microgravity could be a factor that contributes to impaired NK-cell function during long duration space travel.24 month embargo; published online: 20 March 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]