Hyperglycemia-induced activation of human T-lymphocytes with de novo emergence of insulin receptors and generation of reactive oxygen species

Upon activation by phytohemagglutine (PHA), T-lymphocytes (T-cells) express receptors for growth factors, insulin, IGF-1 and IL2 and become insulin sensitive. Diabetic ketoacidosis (DKA) is associated with in vivo emergence of these growth factor receptors without incubation with PHA. As DKA consists of multiple metabolic alterations, in addition to hyperglycemia, we investigated the in vitro effect of different concentrations of glucose (5, 15, and 30 mM) in isolated CD4 of human T-cells at various time intervals (0, 24, 48, and 72 h). Hyperglycemia, but not euglycemia, resulted in de novo emergence of growth factor receptors in a dose- and time-dependent fashion. The activation was also associated with incremental changes in GLUT 4, IRS-1, proinflammatory cytokines, and oxidative stress components. We propose that activation of T-cells with development of insulin receptors in hyperglycemic conditions may serve as a mechanism for control of glucose entry into these cells, thus, protecting them against glucose toxicity.     

Transcriptome and proteome expression in activated human CD4 and CD8 T-lymphocytes

T-lymphocytes (T-cells) are unique in that unlike monocytes, they have no insulin receptors, and are insulin insensitive, but upon activation with antigens develop insulin, IGF-1, and IL-2 receptors, and become insulin sensitive tissues. In vivo activation of these cells has now been demonstrated in patients with diabetic ketoacidosis. We analyzed the genomics and proteomics of activated and non-activated CD4+ and CD8+ T-cells of normal subjects using Affymetrix microarray gene chips and proteomes by SELDI-TOF mass spectrometry analysis. Genes for IL-2, insulin, and IGF-1 receptors were increased at least 2-fold in activated vs non-activated T-cells. Using an expression array containing the entire human genome of 39,500 genes, we evaluated approximately 27,000 genes relevant in physiologic and cellular ontologies. Of these, approximately 10,500 genes were increased in activated cells, compared to about 7,000, which were decreased, and approximately 9500, which were unchanged. Among activated ontologies were signal transduction pathways such as IRS-1, IRS-2, Akt, and glycolytic pathways. To our knowledge this is the first report of an hitherto unreported event. Possible implications of these processes are discussed in the light of their physiological significance.     

Chemotactic activity of porcine insulin for human T lymphocytes in vitro

T lymphocytes bear insulin receptors only after activation and entry into the cell cycle. To determine whether cell motility is concomitant with growth factor action in T lymphocytes, we measured the chemotactic activity of porcine insulin (10(-11) to 10(-5) M) for T lymphocytes. We found that the chemotactic response of human T cells activated with phytohemagglutinin (PHA) to porcine insulin was increased over that of resting T cells, with a concomitant two log leftward shift in the dose response. CD4+ and CD8+ subsets responded identically. Checkerboard analysis showed insulin to be chemotactic, as well as chemokinetic. The nature and time course of acquisition of the dose-response shift suggest that chemotaxis may be signaled by insulin acting on high affinity insulin receptors. The chemotactic effect of insulin exemplifies the general chemotactic effect of growth factors for motile target cells, and may be a useful model for the study of chemotactic signaling in T lymphocytes.     

Heightened NTPDase-1/CD39 expression and angiogenesis in radiation proctitis

Radiation proctitis is an inflammatory process associated with persistent and refractory lower gastrointestinal bleeding. Purinergic signaling regulates hemostasis, inflammation, and angiogenesis. For example, CD39, the vascular ectonucleotidase, blocks platelet activation and is required for angiogenesis. Whether CD39 expression is affected by radiation injury is unknown. The aim of this work was to study CD39 expression patterns after clinical radiation injury to the rectum. We prospectively enrolled eight patients with radiation proctitis and five gender-matched controls. Biopsies were taken from normal-appearing rectal mucosa of controls and from the normal sigmoid and abnormal rectum of patients. Expression patterns of CD39, P2Y2 receptor, CD31, CD61 integrin, and vascular endothelial growth factor receptor 2 were examined by immunostaining; levels of CD39 were further evaluated by Western blots. Chronic inflammatory lesions of radiation proctitis were associated with heightened levels of angiogenesis. Immunohistochemical stains showed increased vascular expression of CD39, as confirmed by Western blots. CD39 was co-localized with vascular endothelial markers CD31 and CD61 integrin, as well as expressed by stromal tissues. Development of neovasculature and associated CD39 expression in radiation proctitis may be associated with the chronic, refractory bleeding observed in this condition.     

Bikunin down-regulates heterodimerization between CD44 and growth factor receptors and subsequently suppresses agonist-mediated signaling

We provided evidence previously that bikunin, a Kunitz-type protease inhibitor, can disrupt dimerization of CD44 proteins, which may result in suppression of receptor-mediated MAP kinase signaling. However, to what extent dimerization may alter ligand-induced signaling has not been documented. Given the recent recognition that some growth factor receptors can form heterodimers with CD44, the present study was undertaken to determine whether the CD44 and growth factor receptors (e.g., EGFR, FGFR, HGFR, VEGFR, TGF-betaRI, or TGF-betaRII) can form heterodimers in cancer cells and, if so, to investigate the potential functional consequences of such heterodimerization. We also examined whether bikunin can abrogate these heterodimerizations and inhibit CD44/growth factor-dependent signaling. Here, we show direct evidence for heterodimerization of CD44-FGFR and CD44-TGF-betaRI in human chondrosarcoma HCS-2/8 cells, CD44-EGFR complex in human glioma U87MG cells, and CD44-TGF-betaRI heterodimer in human ovarian cancer HRA cells. Coupling of CD44 and growth factor receptor may be selective, depending on a cell type. Bikunin does not alter the ligand binding, whereas functionally reduces heterodimerization between CD44 and growth factor receptors. The disruption of heterodimerization substantially reduces receptor-induced tyrosine phosphorylation and ERK1/2 activation. Taken together, our data suggest that bikunin-mediated suppression of heterodimerization between CD44 and growth factors may inhibit the agonist-promoted activation of the signaling pathway.     

Induction of the insulin receptor and other differentiation markers by sodium butyrate in the Burkitt lymphoma cell, Raji

The very low expression of insulin receptors in the Burkitt lymphoma cell Raji was increased 2-fold, 6-fold and 10-fold after 1, 2 and 3 days, respectively, by incubation with the differentiation inducer sodium butyrate. Insulin receptor number was increased without a change in receptor affinity, in association with an increase in the receptor alpha and beta subunits detected after cell-surface labelling and immunoprecipitation. Expression of cell-surface class I and II human leukocyte antigens, the intercellular adhesion molecule-1 and the CD38 leukocyte antigen was also increased, consistent with B cell differentiation. Butyrate effects were not unspecific, as the binding of tumour necrosis factor and growth hormone and the expression of the B cell markers CD20, B5 and CD21 was not increased. The low expression of insulin receptors on Raji cells is therefore a reflection of the less differentiated state of these cells compared to lymphoblastoid cells.     

Treatment of Diabetic Ketoacidosis and the Weekend Effect at an Urban Tertiary-Care Center

Objective: Weekend admission has been associated with higher morbidity and mortality, but the relationship between diabetic ketoacidosis (DKA) outcomes and this weekend effect is unclear. To better characterize it, we examined the outcomes of patients admitted with DKA to an urban tertiary-care center.Methods: This retrospective study included pediatric and adult patients admitted to Montefiore Health System from January 1, 2008, through December 31, 2018, with a primary or secondary diagnosis of DKA as identified by International Classification of Diseases (ICD)-9 and -10 codes; all ICD diagnoses were present on admission. Only the first admission for each patient was analyzed, and patients were excluded if their initial anion gap was less than 13 mEq/L. A subcohort comprised of patients with documented biochemical evidence of DKA resolution was also analyzed. The Friday-Saturday weekend was defined as the period between midnight on Friday and midnight on Sunday; the Saturday-Sunday weekend was similarly defined. The following outcomes were compared between weekday and weekend groups: length of stay; time to initiation of subcutaneous insulin; and time to each of the following: venous pH >7.3, blood glucose <200 mg/dL, and anion gap ≤12 mEq/L. Odds of 30-day all-cause mortality and 30-day all-cause and DKA-specific readmission were also examined.Results: Over 11 years, 4,703 patients were included in the overall cohort, and 648 were included in the subcohort. For both weekend definitions, weekend admission did not produce differences in any outcome for either study cohort.Conclusion: No weekend effect on DKA outcomes was detected at an urban tertiary-care center.Abbreviations: AG = anion gap; CCI = Charlson Comorbidity Index; DKA = diabetic ketoacidosis; ICD = International Classification of Diseases; IVI = intravenous insulin; LOS = length of stay; SCI = subcutaneous insulin     

Expression of the cell adhesion molecules on leukocytes that demarginate during acute maximal exercise.

The pulmonary vascular bed is an important reservoir for the marginated pool of leukocytes that can be mobilized by exercise or catecholamines. This study was designed to determine the phenotypic characteristics of leukocytes that are mobilized into the circulation during exercise. Twenty healthy volunteers performed incremental exercise to exhaustion [maximal O2 consumption (VO2 max)] on a cycle ergometer. Blood was collected at baseline, at 3-min intervals during exercise, at VO2 max, and 30 min after exercise. Total white cell, polymorphonuclear leukocyte (PMN), and lymphocyte counts increased with exercise to VO2 max (P < 0.05). Flow cytometric analysis showed that the mean fluorescence intensity of L-selectin on PMN (from 14.9 +/- 1 at baseline to 9.5 +/- 1.6 at VO2 max, P < 0.05) and lymphocytes (from 11.7 +/- 1.2 at baseline to 8 +/- 0.8 at VO2 max, P < 0.05) decreased with exercise. Mean fluorescence intensity of CD11b on PMN increased with exercise (from 10.2 +/- 0.6 at baseline to 25 +/- 2.5 at VO2 max, P < 0.002) but remained unchanged on lymphocytes. Myeloperoxidase levels in PMN did not change with exercise. In vitro studies showed that neither catecholamines nor plasma collected at VO2 max during exercise changed leukocyte L-selectin or CD11b levels. We conclude that PMN released from the marginated pool during exercise express low levels of L-selectin and high levels of CD11b.     

The immunoregulatory abilities of polymorphonuclear neutrophils in the course of multiple sclerosis.

The polymorphonuclear neutrophils (PMN) possess sufficient potential to affect both immune response and inflammation, however it has not been yet described in the course of multiple sclerosis (MS). We have studied binding of fluorescein isothiocyanate (FITC)- stained TNF-alpha by PMN, the expression of CD11a, CD11b, and CD18 molecules of beta2-integrines and the expression of CD10 (neutral endopeptidase-NEP) and of CD13 (aminopeptidase N; APN) antigens on PMN in three different groups of MS patients. The control group included neurological patients (OND) with noninflammatory diseases. The obtained results have proved that during MS exacerbation and in the course of chronic progressive MS, PMN reveal several forms of preactivation, including significantly higher stained-TNF-alpha binding, higher expression of CD11b and CD18, as well as CD10 and CD13 antigens, in comparison with MS remission or OND. We suggest that the increased expression of these molecules on PMN of MS patients in exacerbation of the disease and to a lower degree in the course of CP-MS is a result of PMN priming, and directly prove the PMN involvement in the disease pathogenesis.     

Intercellular adhesion molecule-1 (ICAM-1)-dependent and ICAM-1-independent adhesive interactions between polymorphonuclear leukocytes and human airway epithelial cells infected with parainfluenza virus type 2.

Acute respiratory virus infections are often associated with an early influx of neutrophils (PMN) into the airways. Maximal cytoxic injury by PMN depends on tight cell-cell adhesion. Infection of some cell types by respiratory and other viruses has been shown to increase PMN adhesion to these cells by undefined mechanisms. We studied adhesion by human PMN to monolayers of primary (1 degree) human tracheal epithelial cells (TEC) or an immortalized cell line derived from human TEC, 9HTEo-, that had been infected with parainfluenza virus type 2 (PiV2). PMN adhesion to uninfected 1 degree TEC was very low (< 5%), but PMN adhesion to PiV2-infected 1 degree TEC was greatly increased (89 +/- 7%). PMN adhesion to 9HTEo- cells was 47 +/- 6%, but increased, 87 +/- 8%, for PiV2-infected 9HTEo- cells. Surface intercellular adhesion molecule-1 (ICAM-1) expression on 1 degree TEC, as determined by immunofluorescence flow cytometry, was relatively low (23 fluorescence units) but doubled by 24 h after PiV2 infection and tripled by 48 h. The 9HTEo- cells constitutively expressed higher levels of surface ICAM-1 (120 units) which did not increase with PiV2 infection. Treatment of non-PiV2-infected 9HTEo- cells with mAb (R6.5) to ICAM-1 reduced PMN adhesion to these cells from 47 +/- 8 to 23 +/- 5%. Identical mAb treatment of either 1 degree TEC or 9HTEo- cells infected with PiV2 had no significant effect on PMN adhesion. Treatment of the PMN with mAb against CD11a, CD11b, or CD18 markedly reduced PMN adhesion to PiV2-infected 1 degree TEC and 9HTEo- cells. We conclude that PiV2 infection of human TEC causes a marked increase in their adhesive interactions with PMN by inducing increased surface expression of both ICAM-1 and one or more, as yet uncharacterized, non-ICAM-1 adhesion molecules that function as counter-receptors for CD11/CD18 on PMN. These mechanisms of adhesion may play a role in epithelial damage during acute respiratory virus infections.