Apoptotic cells were determined by flow cytometry as the fraction of cells labeled with annexin-V that were 7-AAD unfavorable. did not differ significantly between the two groups. Furthermore, monocytes from patients with diabetes experienced a distinctly different gene expression profile compared with monocytes from normal volunteers as assessed with DNA microarray analysis. Specifically, quantitative real-time detection PCR measurements showed an elevated expression of the markers of endoplasmic reticulum (ER) stress in diabetic monocytes, and electron microscopic examination of monocytes revealed morphologic alterations in the ER of cells derived from patients with diabetes. Consistently, the ER stress inducer tunicamycin increased apoptosis of normally healthy monocytes and attenuated the proinflammatory responses to TLR ligands. == CONCLUSIONS == These data suggest that monocytes comprise a substantially impaired subpopulation of PBMCs in patients with diabetes and that ER stress is involved in these pathologic changes mechanistically. This implies that this affected monocytes should be investigated further to better understand diabetic immunity. Type 2 diabetes is the most frequent metabolic disease and the leading cause of human morbidity and mortality (1,2). Based on epidemiologic XL765 data, patients with diabetes are immunocompromised and have an increased incidence of infections in the respiratory tract, urinary tract, and skin (35). The high incidence of colorectal, breast, and pancreatic malignancies in patients with diabetes is also considered to be a consequence of diabetes-associated defects in immune function (6,7). Although studies on immune cells and circulating cytokines have shed some light on this diabetic immunologic phenomenon, conflicting results have been reported and do not properly explain the perturbed immune function in patients with diabetes. Controversial results concerning the phagocytotic activity of polymorphonuclear neutrophils and monocytes are in part due XL765 to differences in the patients themselves, insufficient figures in the study populations, or inconsistencies in the collection of the cell populations under investigation (811). Therefore, further studies are needed to explain the decreased immune function of patients with diabetes. We previously investigated the gene expression signatures of peripheral blood mononuclear cells (PBMCs) in patients with diabetes and observed transcriptional expression features that were unique from those of healthy volunteers (12). Apoptosis-related genes were upregulated in the PBMCs of patients with diabetes. Based on this result, we investigated apoptotic activity and immunologic function in PBMCs from patients with type 2 diabetes. We observed that this CD14+monocyte portion was the most affected subpopulation of PBMCs from these patients; these cells were especially vulnerable to apoptosis compared with other cell subpopulations. We also found that CD14+monocytes exhibited attenuated phagocytotic activity and deficient Toll-like receptor (TLR) signaling, both of which are important for innate immunity (13,14). Transcriptional analysis Ccr7 and electron microscopic examination of monocytes from patients with diabetes showed evidence of endoplasmic reticulum (ER) stress, which may underlie the functional defects in these cells. Collectively, the data presented herein show that CD14+monocytes are a vulnerable cell populace under ER stress in these patients that could contribute to decreases in immune function in diabetes. == RESEARCH DESIGN AND METHODS == Thirty-three patients with type 2 diabetes (male/female, 15/18; age 62.0 8.6 years; A1C 9.2 2.0%) and 28 healthy volunteers (male/female, 15/13; age 58.2 10.2 years; A1C 5.4 0.7%) were enrolled consecutively for the apoptosis assay (Table 1). The groups were not significantly different in terms of their clinical parameters, except for the fasting plasma glucose and A1C levels. The patients with diabetes (n= 16) from whom adequate numbers of monocytes were obtained were enrolled for additional experiments along with 17 other patients with diabetes (male/female, 8/9; age 60.5 7.2 years; XL765 A1C 8.8 1.8%) whose clinical profiles fit the diabetic profile (Table 1). Informed consent for this study was obtained from all subjects. The experimental protocol was carried out relative to the Declaration of Helsinki. == TABLE 1. == Features of the analysis topics Data are means SD. *Diabetic problems: nephropathy, neuropathy, retinopathy, macroangiopathy. FPG, fasting plasma blood sugar; NA, not appropriate. == Isolation of subpopulations of PBMCs and movement cytometric evaluation. == PBMCs had been newly isolated from heparinized venous bloodstream using Ficoll-Hypaque (Sigma-Aldrich, St. Louis, MO) as previously referred to (12). Compact disc4+T-cell and Compact disc14+monocyte subpopulations had been isolated utilizing a magnetic cell sorting program relative to the manufacturer’s process (Miltenyi Biotec, Bergisch Gladbach, Germany). Isolated cells had been purified by >90% as assessed by movement cytometric evaluation using FACSCalibur movement cytometer (BD Biosciences, San Jose, CA). To measure the appearance of TLRs on monocytes, PBMCs had been incubated with phosphatidylethanolamine (PE)-tagged anti-TLR2, -TLR3, or -TLR4 (eBioscience, NORTH PARK, CA) and fluorescein isothiocyanate (FITC)-tagged anti-CD14 antibodies (BD Biosciences) and examined by movement cytometry. Data had been examined using CELLQuest Software program (BD Biosciences). == Quantitative real-time recognition PCR. == Real-time recognition (RTD)-PCR was performed as previously.