Ex vivo TCR‐induced leukocyte gene expression of inflammatory mediators is increased in type 1 diabetic patients but not in overweight children

Abstract

Abnormal systemic concentrations of proinflammatory cytokines/chemokines have been implicated in the development of long-term cardiovascular complications in type 1 diabetes (T1DM) and obesity. Whether leukocyte (WBC) gene expression of these proinflammatory mediators contributes to their increased systemic levels, however, remains unclear, especially in the pediatric patient populations. This study examines mRNA changes of 9 cytokines and chemokines in WBCs following ex vivo immunostimulation from 9 T1DM (13.4±0.5 yr, 4F/5M), 23 overweight (OW, 12.3±0.5 yr, 10F/13M, BMI% 97.1±0.5 and >90.0), and 21 healthy (CL, 13.8±0.7 yr, 9F/12M, BMI% 59.6±4.6 and <85.0) children. All subjects had been maintained in euglycemic conditions for at least 90 min before blood draws. Whole blood was then sampled and incubated with anti-T-cell receptor (TCR) antibody or heat-aggregated IgG (HAG) to stimulate Tcell and Fc receptors, respectively. After lysis of leukocytes, mRNA levels of 6 TNF superfamily cytokines (TNFSF2,5,6,7,9,14) and 3 chemokines (CCL8, 20, and CXCL10) were measured using RT-PCR. Following TCR stimulation, T1DM displayed significantly greater mRNA responses than CL for TNFSF5, 7, 9, and CCL8, and CXCL10; TNFSF9, CCL8, and CXCL10 were also significantly higher in T1DM than OW; no difference was observed between OW and CL. Fc receptor (FcR) stimulation induced similar responses across groups. Therefore, leukocytes of T1DM children displayed exaggerated gene expression in response to ex vivo TCR induction of 5 key proinflammatory cytokines/chemokines. This elevated leukocyte gene expression may be one of the pathophysiological contributors to the development of vascular complications in T1DM.

Aspects of Inflammation and Oxidative Stress in Pediatric Obesity and Type 1 Diabetes: An Overview of Ten Years of Studies

“…The latter observation is in agreement with prior studies indicating that chronic excessive activation of these cells lines is involved in the progression of atherosclerosis and cardiovascular disease in a number of dysmetabolic states [ 12 , 13 ]. Additional evidence that inflammatory processes may be exaggerated in T1DM can also be found in a recent study that focused on observing gene expression of proinflammatory cytokines and chemokines in leukocytes following T-cell receptor and Fc receptor stimulation [ 14 ]. Leukocytes from T1DM children displayed exaggerated gene expression for TNFSF 5, 7, and 9, CCL8, and CXCL10 compared to healthy controls.…”

“…A later study using our standardized exercise challenge, in which a broad panel of cytokines were measured at multiple time points during exercise, further supported this notion with significant elevations of TNF- α and IL-2 and parallel, marked elevation (albeit not statistically significant) of IL-6, IL-4, IL-5, IL-8, IL-10, andIL-13in obese subjects (BMI% > 95) [ 25 ]. In addition to inflammatory cytokines, key oxidative stress markers (MPO and F 2 -isoprostanes) were also observed to be elevated in obese children both at baseline and throughout exercise [ 14 , 26 ]. These studies suggest that chronic inflammation and oxidative stress, which in adults have been suggested as the biochemical link between obesity and its cardiovascular complications, are already markedly activated when obesity is established at a very early age.…”

CXCR3, CXCR5, CXCR6, and CXCR7 in Diabetes

“…This study first shows that in children with newly diagnosed T1D, raised serum CXCL10 and normal CCL2 concentrations indicate a predominant Th1-driven autoimmune process, which shifts toward Th2 immunity over the first 1-2 years from diagnosis [47]. Studies examining the sources of CXCL10 in T1D showed that it was produced by peripheral blood monocytes and leukocytes [48,49]. 4 CXCL10 is highly expressed in lymphocytes infiltrating the human islet; and β-cells, stimulated by cytokines (as IFN-γ and TNF-α), can modulate the autoimmune response releasing CXCL9, CXCL10 and CXCL11.…”

Long Non-Coding RNA Expression Profiling in Obesity Mice with Folic Acid Supplement

“…Nehete et al observed the plasma-circulating levels of pro-inflammatory Th-1 cytokines, interferon gamma, interleukin-6, interleukin-12p40, tumor necrosis factor, soluble CD40 ligand, and interleukin-1β, and those of anti-inflammatory Th-2 cytokines, interleukin-4, interleukin-RA, interleukin-10, and interleukin-13 increase in overweight and obese chimpanzees [29]. In cytokines and chemokines in WBCs, TNF-SF5, 7, and 9 and CCL 8 and 10 are significantly higher in children with type 1 diabetes than in healthy children [30]. Chemokine ligand-2 (CXCL2), a WAT, produces up-regulated chemokines in obesity.…”