De novo emergence of growth factor receptors in activated human CD4+ and CD8+ T lymphocytes

Hyperinsulinemia in Obesity, Inflammation, and Cancer

The relative insufficiency of insulin secretion and/or insulin action causes diabetes. However, obesity and type 2 diabetes mellitus can be associated with an absolute increase in circulating insulin, a state known as hyperinsulinemia. Studies are beginning to elucidate the cause-effect relationships between hyperinsulinemia and numerous consequences of metabolic dysfunctions. Here, we review recent evidence demonstrating that hyperinsulinemia may play a role in inflammation, aging and development of cancers. In this review, we will focus on the consequences and mechanisms of excess insulin production and action, placing recent findings that have challenged dogma in the context of the existing body of literature. Where relevant, we elaborate on the role of specific signal transduction components in the actions of insulin and consequences of chronic hyperinsulinemia. By discussing the involvement of hyperinsulinemia in various metabolic and other chronic diseases, we may identify more effective therapeutics or lifestyle interventions for preventing or treating obesity, diabetes and cancer. We also seek to identify pertinent questions that are ripe for future investigation.

De Novo Assembly and Comparative Transcriptome Profiling of Anser anser and Anser cygnoides Geese Species' Embryonic Skin Feather Follicles

Geese feather production and the quality of downy feathers are additional economically important traits in the geese industry. However, little information is available about the molecular mechanisms fundamental to feather formation and the quality of feathers in geese. This study conducted de novo transcriptome sequencing analysis of two related geese species using the Illumina 4000 platform to determine the genes involved in embryonic skin feather follicle development. A total of 165,564,278 for Anser anser and 144,595,262 for Anser cygnoides clean reads were generated, which were further assembled into 77,134 unigenes with an average length of 906 base pairs in Anser anser and 66,041 unigenes with an average length of 922 base pairs in Anser cygnoides. To recognize the potential regulatory roles of differentially expressed genes (DEGs) during geese embryonic skin feather follicle development, the obtained unigenes were annotated to Gene Ontology (GO), Eukaryotic Orthologous Groups (KOG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) for functional analysis. In both species, GO and KOG had shown similar distribution patterns during functional annotation except for KEGG, which showed significant variation in signaling enrichment. Anser asnser was significantly enriched in the calcium signaling pathway, whereas Anser cygnoides was significantly enriched with glycerolipid metabolism. Further analysis indicated that 14,227 gene families were conserved between the species, among which a total of 20,715 specific gene families were identified. Comparative RNA-Seq data analysis may reveal inclusive knowledge to assist in the identification of genetic regulators at a molecular level to improve feather quality production in geese and other poultry species.

Insulin Receptor-Mediated Stimulation Boosts T Cell Immunity during Inflammation and Infection

T cells represent a critical effector of cell-mediated immunity. Activated T cells engage in metabolic reprogramming during effector differentiation to accommodate dynamic changes in energy demands. Here, we show that the hormone, insulin, and downstream signaling through its insulin receptor shape adaptive immune function through modulating T cell metabolism. T cells lacking insulin receptor expression (LckCre+ Insr^fl/fl) show reduced antigen-specific proliferation and compromised production of pro-inflammatory cytokines. In vivo, T cell-specific insulin receptor deficiency reduces T cell-driven colonic inflammation. In a model of severe influenza infection with A/PR8 (H1N1), lack of insulin receptor on T cells curtails antigen-specific immunity to influenza viral antigens. Mechanistically, insulin receptor signaling reinforces a metabolic program that supports T cell nutrient uptake and associated glycolytic and respiratory capacities. These data highlight insulin receptor signaling as an important node integrating immunometabolic pathways to drive optimal T cell effector function in health and disease.

Effects of insulin on the skin: possible healing benefits for diabetic foot ulcers

Diabetic foot ulcers affect 15-20 % of all diabetic patients and remain an important challenge since the available therapies have limited efficacy and some of the novel therapeutic approaches, which include growth factors and stem cells, are highly expensive and their safety remains to be evaluated. Despite its low cost and safety, the interest for topical insulin as a healing agent has increased only in the last 20 years. The molecular mechanisms of insulin signaling and its metabolic effects have been well studied in its classical target tissues. However, little is known about the specific effects of insulin in healthy or even diabetic skin. In addition, the mechanisms involved in the effects of insulin on wound healing have been virtually unknown until about 10 years ago. This paper will review the most recent advances in the cellular and molecular mechanisms that underlie the beneficial effects of insulin on skin wound healing in diabetes. Emerging evidence that links dysfunction of key cellular organelles, namely the endoplasmic reticulum and the mitochondria, to changes in the autophagy response, as well as the impaired wound healing in diabetic patients will also be discussed along with the putative mechanisms whereby insulin could regulate/modulate these alterations.

A reproducible method for the expansion of mouse CD8+ T lymphocytes

Murine adoptive CD8 + T-cell immunotherapy studies require the generation of large numbers of high viability CD8 + cells. Here we report a tissue culture protocol for the reliable expansion of CD8 + T-cells derived from murine spleen to give a 20-fold expansion after 4 days in culture. The cells were transfected with an mRNA GFP construct and transferred into NOD mice. GFP positive cells could be detected 7 days after transfer thus confirming that the cells survive and are functional for up to 1 week.

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A technique for reliable expansion of murine CD8 + T cells

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Excellent cell viability

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Allows for electroporation of cells with mRNA constructs and detection of expression up to 7 days in vivo

Metabolic mysteries of the inflammatory response: T cell polarization and plasticity

While simultaneously maintaining homeostasis and reducing further harm to the host, the immune system is equipped to eliminate both tumors and pathogenic microorganisms. Bifurcated into cell-mediated and humoral immunity, the adaptive immune system requires a series of complex and coordinated signals to drive the proliferation and differentiation of appropriate subsets. These include signals that modulate cellular metabolism. When first published in the 1920s, "the Warburg effect" was used to describe a phenomenon in which most cancer cells relied on aerobic glycolysis to meet their biosynthetic demands. Despite the early observations of Warburg and his colleagues, targeting cancer cell metabolism for therapeutic purposes still remains theoretical. Notably, many T cells exhibit the same Warburg metabolism as cancer cells and the therapeutic benefit of targeting their metabolic pathways has since been reexamined. Emerging evidence suggests that specific metabolic alterations associated with T cells may be ancillary to their subset differentiation and influential in their inflammatory response. Thus, T cell lymphocyte activation leads to skewing in metabolic plasticity, and issue that will be the subject of this review.

Monocytes, but not T cells, respond to insulin with Akt(S473) phosphorylation independent of the donor glucometabolic state

BACKGROUND

Obesity is associated with insulin resistance and chronic low-grade inflammation. Insulin has been described to have anti-inflammatory effects in immune cells. Therefore, insulin resistance in immune cells can be expected to have important consequences for immune function. Here, we investigate whether freshly isolated monocytes and T cells, isolated from study subjects with a normal or disturbed glucometabolic state, respond to insulin with phosphorylation of Akt, a key molecule in the insulin signalling pathway.

METHODS

A total of 25 study subjects were enrolled in the study. An oral glucose tolerance test (OGTT) was performed, and from fasting insulin and glucose, the homeostasis model assessment of insulin resistance (HOMA-IR) index was calculated. Peripheral blood mononuclear cells were isolated from heparinized blood and phenotypically characterized by flow cytometry. Basal and insulin-induced fractions of pAkt(S473)-positive monocytes and T cells were determined by Phosflow.

RESULTS

On the basis of the OGTT, 11 subjects were classified as normal glucose tolerant (NGT), 9 had an impaired glucose metabolism (IGM) and 5 had type 2 diabetes (T2DM). The fraction of pAkt(S473)positive-T cells and monocytes, in the absence of insulin, was low in all subjects. Incubation with insulin did not induce Akt phosphorylation in CD4⁺ and CD8⁺ T cells in normal subjects. However, in the monocyte fraction, an insulin-dose-dependent increase of the pAkt(S473)positive-cell fraction was observed. This response did not differ between NGT, IGM and T2DM and was not correlated with HOMA-IR.

CONCLUSIONS

In this study, we show that freshly isolated monocytes, but not T cells, are insulin-sensitive cells and that this insulin sensitivity of monocytes is not negatively affected by the glucometabolic state of the donor.

Metabolism of activated T lymphocytes

Activated T cells undergo metabolic reprogramming which promotes glycolytic flux and lactate production as well as elevated production of lipids, proteins, nucleic acids and other carbohydrates (i.e. induction of biomass) even in the presence of oxygen. Activated T cells show induced expression of, among other things, Glucose Transporter 1 and several glycolytic enzymes, including ADP-Dependent Glucokinase and the low affinity isoform Pyruvate Kinase-M2 (which promote glycolytic flux), as well Glutamine Transporters and Glycerol-3-phosphate Dehydrogenase 2 which make available glutamate and glycerol-3-phosphate as mitochondrial energy sources. Intracellular leucine concentrations critically regulate mammalian target of rapamycin (mTOR) signaling to promote Th1, Th2, and Th17 CD4(+) T effector cell differentiation. In contrast, T regulatory (Treg) cells are generated when AMP-Activating Protein Kinase signaling is activated and mTOR activation is suppressed. Unlike effector CD4(+) and CD8(+) T cells, Tregs and memory T cells oxidize fatty acids for fuel. Effector and memory T cells perform different functions and thus show distinct metabolic profiles which are exquisitely controlled by cellular signaling. Upon activation, T cells express the insulin and leptin receptors on their surface and become sensitive to insulin signaling and nutrient availability and show changes in differentiation. Thus, metabolism and nutrient availability influence T cell activation and function.

Insulin resistance, metabolic stress, and atherosclerosis

Atherosclerosis, a pathological process that underlies the development of cardiovascular disease, is the primary cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). T2DM is characterized by hyperglycemia and insulin resistance (IR), in which target tissues fail to respond to insulin. Systemic IR is associated with impaired insulin signaling in the metabolic tissues and vasculature. Insulin receptor is highly expressed in the liver, muscle, pancreas, and adipose tissue. It is also expressed in vascular cells. It has been suggested that insulin signaling in vascular cells regulates cell proliferation and vascular function. In this review, we discuss the association between IR, metabolic stress, and atherosclerosis with focus on 1) tissue and cell distribution of insulin receptor and its differential signaling transduction and 2) potential mechanism of insulin signaling impairment and its role in the development of atherosclerosis and vascular function in metabolic disorders including hyperglycemia, hypertension, dyslipidemia, and hyperhomocysteinemia. We propose that insulin signaling impairment is the foremost biochemical mechanism underlying increased cardiovascular morbidity and mortality in atherosclerosis, T2DM, and metabolic syndrome.

Beyond the hormone: insulin as an autoimmune target in type 1 diabetes

Insulin is not only the hormone produced by pancreatic β-cells but also a key target antigen of the autoimmune islet destruction leading to type 1 diabetes. Despite cultural biases between the fields of endocrinology and immunology, these two facets should not be regarded separately, but rather harmonized in a unifying picture of diabetes pathogenesis. There is increasing evidence suggesting that metabolic factors (β-cell dysfunction, insulin resistance) and immunological components (inflammation and β-cell-directed adaptive immune responses) may synergize toward islet destruction, with insulin standing at the crossroad of these pathways. This concept further calls for a revision of the classical dichotomy between type 1 and type 2 diabetes because metabolic and immune mechanisms may both contribute to different extents to the development of different forms of diabetes. After providing a background on the mechanisms of β-cell autoimmunity, we will explain the role of insulin and its precursors as target antigens expressed not only by β-cells but also in the thymus. Available knowledge on the autoimmune antibody and T-cell responses against insulin will be summarized. A unifying scheme will be proposed to show how different aspects of insulin biology may lead to β-cell destruction and may be therapeutically exploited. We will argue about possible reasons why insulin remains the mainstay of metabolic control in type 1 diabetes but has so far failed to prevent or halt β-cell autoimmunity as an immune modulatory reagent.

Transcriptome and proteome expressions involved in insulin resistance in muscle and activated T-lymphocytes of patients with type 2 diabetes

We analyzed the genes expressed (transcriptomes) and the proteins translated (pro- teomes) in muscle tissues and activated CD4(+) and CD8(+) T-lymphocytes (T-cells) of five Type 2 diabetes (T2DM) subjects using Affymetrix microarrays and mass spectrometry, and compared them with matched non-diabetic controls. Gene expressions of insulin receptor (INSR), vitamin D receptor, insulin degrading enzyme, Akt, insulin receptor substrate-1 (IRS-1), IRS-2, glucose transporter 4 (GLUT4), and enzymes of the glycolytic pathway were decreased at least 50% in T2DM than in controls. However, there was greater than two-fold gene upregulation of plasma cell glycoprotein-1, tumor necrosis factor alpha (TNFalpha, and gluconeogenic enzymes in T2DM than in controls. The gene silencing for INSR or TNFalpha resulted in the inhibition or stimulation of GLUT4, respectively. Proteome profiles corresponding to molecular weights of the above translated transcriptomes showed different patterns of changes between T2DM and controls. Meanwhile, changes in transcriptomes and proteomes between muscle and activated T-cells of T2DM were comparable. Activated T-cells, analogous to muscle cells, expressed insulin signaling and glucose metabolism genes and gene products. In conclusion, T-cells and muscle in T2DM exhibited differences in expression of certain genes and gene products relative to non-diabetic controls. These alterations in transcriptomes and proteomes in T2DM may be involved in insulin resistance.

Monitoring Biological Action of Rapamycin in Renal Transplantation

BACKGROUND

Inhibition of P70S6 kinase (P70(S6K)) phosphorylation in activated T cells is 1 of the major mechanisms by which rapamycin exerts its immunosuppressive action.

STUDY DESIGN

Observational cohort study.

SETTINGS & PARTICIPANTS

2 different groups of kidney transplant recipients at a single center: 30 transplant recipients converted from mycophenolic acid and low-dose prednisone plus cyclosporine A to mycophenolic acid and low-dose prednisone plus rapamycin therapy for chronic allograft nephropathy (group 1) and 16 recipients of suboptimal organs converted from tacrolimus plus rapamycin to rapamycin therapy alone after 3 months (group 2).

PREDICTOR

Exposure to rapamycin therapy and rapamycin trough levels.

OUTCOMES & MEASUREMENTS

Basal and stimulated phosphorylation of P70(S6K) was measured by using Western blotting in patients' peripheral-blood mononuclear cells before and 6 to 11 months after conversion to rapamycin-based therapy. Kinase activation was attained in vivo by means of intravenous insulin injection.

RESULTS

The potency of rapamycin inhibition of P70(S6K) phosphorylation varied among patients (RAPA blood concentration required to achieve 50% inhibition of P70(S6K) activation for mitogen-activated kinase, 3.14 to 12.14 ng/mL) and failed to correlate with drug trough levels. The combination of tacrolimus and rapamycin limited the inhibitory effect of the latter drug on P70(S6K) activation.

LIMITATIONS

Need for additional studies exploring the relationship between P70(S6K) activity and kidney graft outcome. Exclusion of patients with diabetes.

CONCLUSIONS

Long-term rapamycin treatment inhibits P70(S6K) phosphorylation in peripheral-blood mononuclear cells without significant correlation with rapamycin trough levels. By measuring in vivo the biological action of rapamycin, the assay may provide potentially relevant information for the clinical management of rapamycin-treated patients.

Glucose transporter expression on the plasma membrane of resting and activated white blood cells

BACKGROUND

In white blood cells (WBC), the increase in glucose utilization is a prominent feature during immune response and this depends on the function of specific glucose transporter (GLUT) isoforms. The objective was to examine the effects of activation by Phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS) and insulin on the expression of GLUT isoforms in all subpopulations of WBC.

MATERIALS AND METHODS

Blood was withdrawn from 27 healthy subjects. The expression of GLUT1, GLUT3 and GLUT4 on the plasma membrane of resting and activated monocytes, T- and B-lymphocytes and polymorphonuclear cells (PMNs) was determined in the absence and presence of physiological concentrations of insulin, by flow cytometry.

RESULTS

GLUT1 did not respond to insulin in either resting or PMA/LPS activated state. In the resting state, monocytes and B-lymphocytes increased the abundance of GLUT3 and GLUT4 on their plasma membrane in response to insulin; in contrast, T-lymphocytes and PMNs were unresponsive to insulin. In the activated state, monocytes, B- and T- lymphocytes increased the expression of all three GLUT isoforms on their plasma membrane, whilst PMNs increased only GLUT1 and GLUT3; in all WBC, insulin augmented the expression of GLUT4 and GLUT3 isoforms in addition to the stimulation provided by the PMA or LPS treatment alone.

CONCLUSION

Activation of WBC leads to increased expression of GLUT1, GLUT3 and GLUT4 isoforms on their plasma membrane; this process was further augmented by insulin. During infection, these mechanisms may help to redistribute glucose as a potential source of energy away from peripheral tissues and direct it towards cells that mediate the immune response and are therefore crucial to survival.

Diabetes induces rapid suppression of adaptive immunity followed by homeostatic T-cell proliferation

Surprisingly, the effect of acute diabetes on immunity has not been examined in detail. We, herein, show for the first time that untreated acute diabetes causes rapid lymphopenia followed by homeostatic T-cell proliferation. The diabetes-induced lymphopenia was associated with an immunosuppressed state that could be sufficiently strong to allow engraftment of fully allogeneic beta-cells or block rejection of islet transplants. In contrast, homeostatic proliferation and recovery of T-cell numbers were associated with islet rejection. Thus, the timing of islet transplant challenge in relation to diabetes induction was critical in determining whether islets were accepted or rejected. In addition, we tested whether diabetes-related immunosuppression could result in an overestimation of the efficacy of a tolerance-inducing protocol. Consistent with this possibility, a protocol targeting CD40L and ICOS that we have shown induces tolerance in diabetic recipients was unable to induce tolerance in non-diabetic recipients. The data uncover a previously unrecognized suppressive effect of diabetes on adaptive immunity. Furthermore, they suggest that the standard methods of testing new tolerance-inducing protocols in islet transplantation require modification and that diabetes itself can contribute to homeostatic proliferation, a process associated with autoimmunity and a resistance to tolerance induction.

Potential antiinflammatory role of insulin via the preferential polarization of effector T cells toward a T helper 2 phenotype

Hyperglycemia in critical illness is a common complication and a strong independent risk factor for morbidity and death. Intensive insulin therapy decreases this risk by up to 50%. It is unclear to what extent this benefit is due to reversal of glucotoxicity or to a direct effect of insulin, because antiinflammatory effects of insulin have already been described, but the underlying mechanisms are still poorly understood. The insulin receptor is expressed on resting neutrophils, monocytes, and B cells, but is not detectable on T cells. However, significant up-regulation of insulin receptor expression is observed on activated T cells, which suggests an important role during T cell activation. Exogenous insulin in vitro induced a shift in T cell differentiation toward a T helper type 2 (Th2)-type response, decreasing the T helper type 1 to Th2 ratio by 36%. This result correlated with a corresponding change in cytokine secretion, with the interferon-gamma to IL-4 ratio being decreased by 33%. These changes were associated with increased Th2-promoting ERK phosphorylation in the presence of insulin. Thus, we demonstrate for the first time that insulin treatment influences T cell differentiation promoting a shift toward a Th2-type response. This effect of insulin in changing T cell polarization may contribute to its antiinflammatory role not only in sepsis, but also in chronic inflammation associated with obesity and type 2 diabetes.

Comparison of the insulin reaction of peripheral blood T cells between healthy Holstein dairy cows and JB during the periparturient period

To compare the changes in the insulin reaction of Holstein dairy cows and Japanese Black cows (JB) during the periparturient period, the insulin resistance test in vivo and lymphocytes proliferation with insulin in vitro were performed. Ten healthy Holstein dairy cows (Holstein group) and 10 healthy JB cows (JB group) used in this study were observed on days 60, 40, and 20 before calving and days 7 and 20 after calving. In insulin resistance reaction in vivo and in vitro, a low insulin-stimulated glucose disposal rate and lymphocyte proliferation with insulin were observed in the Holstein group compared with the JB group during the experimental period. An analysis of the lymphocytes cultured with insulin showed that the percentage of CD4+CD45R- T cells in the Holstein group was significantly lower than that of the JB group before day 20. These findings indicate that T cells reaction to insulin in healthy periparturient Holstein cows is lower than that in Japanese Black.

Palmitic acid-induced activation of human T-lymphocytes and aortic endothelial cells with production of insulin receptors, reactive oxygen species, cytokines, and lipid peroxidation

Diabetic conditions are associated with hyperglycemia and hyperlipidemia, but the role of saturated fatty acids (SFA) vs. unsaturated fatty acids (UFA) in activation of T-lymphocytes and human aortic endothelial cells (HAEC) is not known. We investigated in vitro effects of various concentrations of SFA (palmitate) and UFA (oleic, linoleic, linolenic, and arachidonic) acids in activation of these cells. These cells in presence of palmitate, but not UFA, exhibited time, and concentration-dependent emergence of insulin receptors, GLUT 4 expression, generation of ROS, cytokines, lipid peroxidation, and IRS-1. We conclude that both T-lymphocytes and HAEC share common characteristics in exhibiting activation of these cells to palmitate, but not to UFA, by developing insulin receptors and becoming insulin responsive tissues, a hitherto unknown response to palmitate. We hypothesize that these events may serve as protective defense mechanisms against acute effects of glucotoxicity and lipotoxicity in these cells.

Insulin resistance and atherosclerosis

The epidemic of obesity in the developed world over the last two decades is driving a large increase in type 2 diabetes and consequentially setting the scene for an impending wave of cardiovascular morbidity and mortality. It is only now being recognized that the major antecedent of type 2 diabetes, insulin resistance with its attendant syndrome, is the major underlying cause of the susceptibility to type 2 diabetes and cardiovascular disease. In metabolic tissues, insulin signaling via the phosphatidylinositol-3-kinase pathway leads to glucose uptake so that in insulin resistance a state of hyperglycemia occurs; other factors such as dyslipidemia and hypertension also arise. In cardiovascular tissues there are two pathways of insulin receptor signaling, one that is predominant in metabolic tissues (mediated by phosphatidylinositol-3-kinase) and another being a growth factor-like pathway (mediated by MAPK); the down-regulation of the former and continued activity of the latter pathway leads to atherosclerosis. This review addresses the metabolic consequences of the insulin resistance syndrome, its relationship with atherosclerosis, and the impact of insulin resistance on processes of atherosclerosis including insulin signaling in cells of the vasculature.

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.

Elastin-derived peptides induce a T-helper type 1 polarization of human blood lymphocytes

OBJECTIVE

Increased level of elastin-derived peptides (EDPs) is observed in the serum of patients with manifestations of arterial diseases. We here investigated whether EDPs might exert, at systemic level, a regulatory role for the T-helper type 1 (Th-1)/Th-2 cellular immune response by human peripheral blood lymphocytes (PBLs) expressing the spliced-galactosidase (S-gal)-elastin receptor.

METHODS AND RESULTS

Using flow cytometry and Western blot analysis, we demonstrated that EDPs led to an activation of the S-gal-elastin receptor associated with cytokine production on PBLs and CD4+ T cell subpopulations. The constitutive expression of the S-gal-elastin receptor at the surface of human PBLs was upregulated at the mRNA (RT-PCR) and protein (ELISA) levels on cell activation. In nonactivated and phytohemagglutinin-activated conditions, expressions of the predominant Th-2 cytokine interleukin-5 (IL-5) and IL-10 were reduced, whereas those of the major Th-1 cytokines interferon-gamma and IL-2 were enhanced by EDPs. Furthermore, we evidenced that EDPs could not only potentiate the IL-12-induced Th-1 profile but also could reverse the Th-2 (over Th-1) profile induced by IL-4. Finally, Th-1 cytokine upregulation was associated to an increased activator protein-1 DNA binding and enhanced pro-matrix metalloproteinase-9 secretion.

CONCLUSIONS

This study highlights the importance of EDPs as stimuli for Th-1 differentiation, whether T cells are in an inactivated state or already orientated toward a Th-1 (IL-12) or Th-2 (IL-4) response.

Increased central memory T cells in patients with chronic pancreatitis

BACKGROUND/AIMS

A dysregulated immune response has been suggested to be important for the pathogenesis of chronic pancreatitis (CP). Formation of immunological memory is based on the differentiation of naive T lymphocytes to memory T lymphocytes after exposure to antigens and specific cytokines. The aim of this study was to analyze peripheral blood mononuclear cells (PBMCs) in patients with CP for different T lymphocyte subsets including naive and memory T cells.

METHODS

PBMCs from 9 patients who had undergone pancreatic resection due to CP, 9 CP patients who had not been resected and 9 healthy controls were analyzed by flow cytometry.

RESULTS

Patients with CP had a skewed distribution of T lymphocytes, with an increased level of CCR7+/CD45RA- central memory T lymphocytes compared to healthy controls. Nonresected CP patients and subjects who had undergone pancreatic resection due to CP had similar levels of central memory T lymphocytes.

CONCLUSION

Our results indicate that the dysregulation of the immune system in chronic pancreatitis seems to persist even after removal of large parts of the local inflammatory site. We suggest that the increase of central memory T lymphocytes may be important for maintaining the inflammatory process in chronic pancreatitis.

Dendritic epidermal T cells regulate skin homeostasis through local production of insulin-like growth factor 1

A fine balance between rates of proliferation and apoptosis in the skin provides a defensive barrier and a mechanism for tissue repair after damage. Vgamma3(+) dendritic epidermal T cells (DETCs) are primary modulators of skin immune responses. Here we show that DETCs both produce and respond to insulin-like growth factor 1 (IGF-1) after T cell receptor stimulation. Mice deficient in DETCs had a notable increase in epidermal apoptosis that was abrogated by the addition of DETCs or IGF-1. Furthermore, DETC-deficient mice had reduced IGF-1 receptor activation at wound sites. These findings indicate critical functions for DETC-mediated IGF-1 production in regulating skin homeostasis and repair.

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.

Diabetic ketoacidosis induces in vivo activation of human T-lymphocytes

Diabetic ketoacidosis (DKA) is an inflammatory state associated with immune responses in polymorphonuclear cells (PMN). Activation of subgroup of T-lymphocytes in PMN of DKA patients, however, is not known. We studied in vivo activation of CD4 and CD8 lymphocytes by measuring de novo growth factor receptor for insulin, IGF-1, and IL-2 in eight patients on admission and at resolution of DKA, and compared them with matched controls. The presence of these receptors was demonstrated in all patients' lymphocytes on admission, but not in control subjects. This event was associated with increased levels of thiobarbituric acid-reacting material and dichlorofluorescien, as markers of oxidative stress. Based on these new findings and works in the literature, we hypothesize that hyperglycemia/ketosis results in increased reactive oxygen species, leading to increased levels of cytokines and emergence of growth factor receptors. We propose DKA changes the T-lymphocytes to insulin sensitive tissues as a compensatory mechanism.