| 1. |
- Che, Karlhans Fru, et al.
(author)
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Cross Talk between P38MAPK and STAT3 Regulates Expression of Negative Costimulatory Molecules and Transcriptional Repressors in HIV-1 Primed T cells
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Other publication (other academic/artistic)abstract
- HIV-1 infection enhances the expression of negative costimulatory molecules on T cellsleading to T cell impairment. The signaling pathway underlying the regulation ofinhibitory molecules and the subsequent onset of T cell impairment remains to beinvestigated. Herein, we showed that the T cells activated by HIV-pulsed dendritic cells(DCs) upregulated CTLA-4, TRAIL, LAG-3, TIM-3, and CD160 and suppressionassociated transcription factors BLIMP-1, DTX1, and FOXP3, leading to T cellsuppression. The induction of suppressor T cells was regulated by the signal transducerand activator of transcription 3 (STAT3) molecules as blockade of this pathwaysignificantly down regulates the expression of inhibitory molecules. The cytokines IL-6and IL-10 were not responsible for STAT3 activation as their neutralization could neitherrecover T cell proliferation nor decrease the expression of negative costimulatorymolecules. Contrarily, we demonstrated that the intracytoplasmic cross-talk of P38Mitogen-Activated Protein Kinase (MAPK) with STAT3 was responsible as blockade ofthe P38MAPK significantly impaired negative costimulatory molecular expression andthe subsequent recovery of T cell proliferation. Notably, the blockade of viral access toDC cytosol, via CD4 binding and fusion, significantly reduced the negative effects DCsimposed on the primed T cells. In conclusion, viral access to cytosol modulated theDCs- T cell priming to induce T cells with upreguled expression of negativecostimulatory molecules in a P38MAPK/STAT3 pathway dependent fashion
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| 2. |
- Che, Karlhans Fru
(author)
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Immunomodulatory Effects of Human ImmunodeficiencyVirus (HIV-1) on Dendritic Cell and T cell Responses : Studies of HIV-1 effects on Dendritic cell functionality reflected in primed T cells
- 2011
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Doctoral thesis (other academic/artistic)abstract
- The human immunodeficiency virus (HIV)-1 is the causative agent of acquired immune deficiency syndrome (AIDS) worldwide. Till date there are no vaccines or cure for this infection as the virus has adapted myriad ways to remain persistent in the host where it causes severe damage to the immune system. Both humoral and cellular immune responses are mounted against HIV-1 during the initial phase of infection but fail to control viral replication as these responses are severely depleted during disease progression. Of great importance in HIV-1 research today is the in depth understanding of the types of immune responses elicited, the mechanisms behind their decline and how these responses can be maintained overtime.The focus of this thesis was to examine the possibility of priming HIV-1 specific T cell responses in vitro from whole viral particles and in detail, scrutinize the type of T cell responses and epitope specificities generated. Next was to investigate in vitro the factors responsible for impaired immune responses in HIV-1 infected individuals. We were also interested in understanding the underlying mechanisms through which HIV-1 initiate suppression of T cell functionality.Results showed that using HIV-1 pulsed monocyte derived dendritic cells (DCs), we were able to prime HIV-1 specific CD4+ and CD8+ T cells from naïve T cells in vitro. The epitopes primed in vitro were located within the HIV-1 envelope, gag, and pol proteins and were confirmed ex vivo to exist in acute and chronically infected individuals. We established that many of the novel CD4+ T cell epitopes primed in vitro also existed in vivo in HIV-1 infected individuals during acute infection. These responses declined/disappeared early on, which is in line with HIV-1 preferential infection of HIV-1 specific CD4+ T cells.Besides declining HIV-1 specific T cell responses, many HIV-1 infected individuals also have impaired T cell functionality. We established that one reason behind the decline and impairment in immune responses was the increased expression of inhibitory molecules PD-1, CTLA-4, and TRAIL on HIV-1 primed T cells. These T cells had the capacity to suppress new responses in a cell-cell contact dependent manner. The ability of the HIV-1 primed T cells to proliferate was severely impaired and this condition was reversed after a combined blockade of PD-1, CTLA-4 and TRAIL. Furthermore, more inhibitory molecules TIM-3, LAG-3, CD160, BLIMP-1, and FOXP3 were also found increased at both gene and protein levels on HIV-1 primed T cells. Additionally, we showed decreased levels of functional cytokines IL-2, IFN-γ and TNF-α, and the cytolytic proteins perforin and granzyme in DC T cell priming cocultures containing HIV-1. This could be as a result of the decreased T cell activation or impaired production by T cells. The mechanisms responsible for the elevated levels of inhibitory molecules emanated mainly from the P38MAPK/STAT3 pathways. Blockade of these pathways in both allogeneic and autologous DC-T cell assays significantly suppressed expression of inhibitory molecules and subsequently rescued T cell proliferation.In conclusion, HIV-1 pulsed DCs have the capacity to prime HIV-1 specific responses in vitro that do exist in HIV-1 infected individuals and we found evidence that many of these responses were eliminated rapidly in HIV-1 infected individuals. HIV-1 triggers through P38MAPK/STAT3 pathway the synthesis of inhibitory molecules, namely CTLA-4, PD-1, TRAIL, TIM-3, LAG-3, CD160, and suppression associated transcription factors FOXP3, BLIMP-1 and DTX1. This is followed by decreased T cell proliferation and functionality which are much needed to control viral replication.
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| 3. |
- Che, Karlhans Fru, et al.
(author)
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p38 Mitogen-Activated Protein Kinase/Signal Transducer and Activator of Transcription-3 Pathway Signaling Regulates Expression of Inhibitory Molecules in T Cells Activated by HIV-1-Exposed Dendritic Cells
- 2012
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In: Molecular Medicine. - : Feinstein Institute for Medical Research. - 1076-1551 .- 1528-3658. ; 18:8, s. 1169-1182
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Journal article (peer-reviewed)abstract
- Human immunodeficiency virus type 1 (HIV-1) infection enhances the expression of inhibitory molecules on T cells, leading to T-cell impairment. The signaling pathways underlying the regulation of inhibitory molecules and subsequent onset of T-cell impairment remain elusive. We showed that both autologous and allogeneic T cells exposed to HIV-pulsed dendritic cells (DCs) upregulated cytotoxic T-lymphocyte antigen (CTLA-4), tumor-necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), lymphocyte-activation gene-3 (LAG3). T-cell immunoglobulin mucin-3 (TIM-3), CD160 and certain suppression-associated transcription factors, such as B-lymphocyte induced maturation protein-1 (BLIMP-1), deltex homolog 1 protein (DTX1) and forkhead box P3 (FOXP3), leading to T-cell suppression. This induction was regulated by p38 mitogen-activated protein kinase/signal transducer and activator of transcription-3 (P38MAPK/STAT3) pathways, because their blockade significantly abrogated expression of all the inhibitory molecules studied and a subsequent recovery in T-cell proliferation. Neither interleukin-6 (IL-6) nor IL-10 nor growth factors known to activate STAT3 signaling events were responsible for STAT3 activation. Involvement of the P38MAPK/STAT3 pathways was evident because these proteins had a higher level of phosphorylation in the HIV-1-primed cells. Furthermore, blockade of viral CD4 binding and fusion significantly reduced the negative effects DCs imposed on primed T cells. In conclusion, HIV-1 interaction with DCs modulated their functionality, causing them to trigger the activation of the P38MAPK/STAT3 pathway in T cells, which was responsible for the upregulation of inhibitory molecules. Online address: http://www.molmed.org doi: 10.2119/molmed.2012.00103
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| 4. |
- Che, Karlhans Fru, et al.
(author)
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Pharmacological Modulation of Endotoxin-Induced Release of IL-26 in Human Primary Lung Fibroblasts
- 2019
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In: Frontiers in Pharmacology. - : FRONTIERS MEDIA SA. - 1663-9812. ; 10
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Journal article (peer-reviewed)abstract
- Background: Interleukin (IL)-26 is a neutrophil-mobilizing and bactericidal cytokine that is enhanced in human airways in vivo in response to endotoxin from Gram-negative bacteria. This cytokine is also enhanced in the airways during exacerbations of chronic obstructive pulmonary disease (COPD). Here, we investigated whether human primary lung fibroblasts (HLF) release IL-26 constitutively and in response to TLR4 stimulation by endotoxin and characterized the effects of bronchodilatory and anti-inflammatory drugs utilized in COPD. Methods: The HLF were stimulated with different concentrations of endotoxin. Cells were also treated with different concentrations of bronchodilatory and anti-inflammatory drugs, with and without endotoxin stimulation. Cytokine protein concentrations were quantified in the cell-free conditioned media [enzyme-linked immunosorbent assay (ELISA)], and the phosphorylation levels of intracellular signaling molecules were determined (phosphoELISA). Results: Whereas HLF displayed constitutive release of IL-26 into the conditioned medium, endotoxin markedly enhanced this release, as well as that of IL-6 and IL-8. This cytokine release was paralleled by increased phosphorylation of the intracellular signaling molecules NF-kappa B, c-Jun N-terminal kinase (JNK) 1-3, p38, and extracellular signal-regulated kinase (ERK) 1/2. The glucocorticoid hydrocortisone caused substantial inhibition of the endotoxin-induced release of IL-26, IL-6, and IL-8, an effect paralleled by a decrease of the phosphorylation of NF-kappa B, p38, and ERK1/2. The muscarinic receptor antagonist (MRA) tiotropium, but not aclidinium, caused minor inhibition of the endotoxin-induced release of IL-26 and IL-8, paralleled by a decreased phosphorylation of NF-kappa B. The beta 2-adrenoceptor agonist salbutamol caused modest inhibition of the endotoxin-induced release of IL-26 and IL-8, paralleled by a decreased phosphorylation of NF-kappa B, JNK1-3, and p38. Similar pharmacological effects were observed for the constitutive release of IL-26. Conclusions: The HLF constitute an abundant source of IL-26 that may contribute to local host defense against Gram-negative bacteria. Among the tested drugs, the glucocorticoid displayed the most powerful inhibitory effect, affecting the NF-kappa B, p38, and ERK1/2 signaling pathways. Whether or not this inhibition of IL-26 contributes to an increased risk for local infections in COPD requires further evaluation.
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| 5. |
- Che, Karlhans Fru, et al.
(author)
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The neutrophil-mobilizing cytokine interleukin-26 in the airways of long-term tobacco smokers
- 2018
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In: Clinical Science. - 0143-5221. ; 132:9, s. 959-983
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Journal article (peer-reviewed)abstract
- Long-term tobacco smokers with chronic obstructive pulmonary disease (COPD) or chronic bronchitis display an excessive accumulation of neutrophils in the airways; an inflammation that responds poorly to established therapy. Thus, there is a need to identify new molecular targets for the development of effective therapy. Here, we hypothesized that the neutrophil-mobilizing cytokine interleukin (IL)-26 (IL-26) is involved in airway inflammation amongst long-term tobacco smokers with or without COPD, chronic bronchitis or colonization by pathogenic bacteria. By analyzing bronchoalveolar lavage (BAL), bronchail wash (BW) and induced sputum (IS) samples, we found increased extracellular IL-26 protein in the airways of long-term smokers in vivo without further increase amongst those with clinically stable COPD. In human alveolar macrophages (AM) in vitro, the exposure to water-soluble tobacco smoke components (WTC) enhanced IL-26 gene and protein. In this cell model, the same exposure increased gene expression of the IL-26 receptor complex (IL10R2 and IL20R1) and nuclear factor κ B (NF-κB); a proven regulator of IL-26 production. In the same cell model, recombinant human IL-26 in vitro caused a concentration-dependent increase in the gene expression of NF-κB and several pro-inflammatory cytokines. In the long-term smokers, we also observed that extracellular IL-26 protein in BAL samples correlates with measures of lung function, tobacco load, and several markers of neutrophil accumulation. Extracellular IL-26 was further increased in long-term smokers with exacerbations of COPD (IS samples), with chronic bronchitis (BAL samples ) or with colonization by pathogenic bacteria (IS and BW samples). Thus, IL-26 in the airways emerges as a promising target for improving the understanding of the pathogenic mechanisms behind several pulmonary morbidities in long-term tobacco smokers.
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| 6. |
- Hedlund, Sebastian, et al.
(author)
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Dendritic cell activation by sensing Mycobacterium tuberculosis-induced apoptotic neutrophils via DC-SIGN
- 2010
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In: HUMAN IMMUNOLOGY. - : Elsevier Science B.V., Amsterdam.. - 0198-8859 .- 1879-1166. ; 71:6, s. 535-540
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Journal article (peer-reviewed)abstract
- Mycobacterium tuberculosis (Mtb) manipulates cells of the innate immune system to provide the bacteria with a sustainable intracellular niche. Mtb spread through aerosol carrying them deep into the lungs, where they are internalized by phagocytic cells, such as neutrophils (PMNs), dendritic cells (DCs), and macrophages. PMNs undergo accelerated apoptosis after interaction with the bacterium, and apoptotic cells are sequestered by neighboring phagocytes. Removal of aged apoptotic cells because of natural tissue turnover is described as an immunologically silent process facilitating resolution of inflammation and inhibition of DC maturation. Silencing of immune cells could be favorable for intracellular bacteria. The aim of this study was to clarify the interaction between Mtb-induced apoptotic PMNs and DCs, and evaluate whether this interaction follows the proposed anti-inflammatory pathway. In contrast to aged apoptotic cells, Mtb-induced apoptotic PMNs induced functional DC maturation. We found that the cell fraction from Mtb-induced apoptotic PMNs contained almost all stimulatory capacity, suggesting that cell-cell interaction is crucial for DC activation. Inhibitory studies showed that this cell contact-dependent activation required binding of the PMN Mac-1 (CD11b/CD18) to the DC via DC-SIGN and endocytic activity involving the alpha(v)beta(5) but did not involve the scavenger receptor CD36. Taken together, this study demonstrates that the DCs can distinguish between normal and infected apoptotic PMNs via cellular crosstalk, where the DCs can sense the presence of danger on the Mtb-infected PMNs and modulate their response accordingly.
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| 7. |
- Paulsson, Magnus, et al.
(author)
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Vitronectin is produced in the lung upon infection by respiratory pathogens, and is utilized to evade the innate immunity
- 2017
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In: ; , s. 132-132
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Conference paper (peer-reviewed)abstract
- Bacterial extracellular vesicles (EVs) are shed during growth by the respiratory pathogens Pseudomonas aeruginosa and Haemophilus influenzae. Vesicles trigger release of antimicrobial compounds and proteins of the complement, which are partly regulated by vitronectin. We hypothesized that vitronectin is elevated in the lungs during pneumonia, that respiratory epithelial cells produce vitronectin upon bacterial stimulation and that vitronectin is utilized by bacteria for increased virulence. Vitronectin-concentrations were measured by ELISA in bronchoalveolar lavage fluid (BALF) from patients with pneumonia (n=8) and from healthy volunteers (n=13) with or without pulmonary endotoxin instillation. Elevated vitronectin concentrations were found in BALF collected during pneumonia compared to healthy individuals (p=0.0063) and in endotoxin-challenged pulmonary segments compared to control segments (after 12h: p=0.031; 48h: p=0.016). Flow cytometry revealed that bacteria captured vitronectin from BALF onto their surface and subsequently became less sensitive to killing by serum compared to controls (P. aeruginosa p=0.016, H. influenzae p=0.011). Increased levels of VTN mRNA after one hour (p=0.022) and increased surface bound vitronectin after 24h (p<0.001) were observed with type II bronchial alveolar epithelial cells (A549) after stimulation with EVs. In conclusion, elevated vitronectin concentrations were found in BALF from patients with pneumonia and in healthy volunteers after pulmonary endotoxin instillation. Cellular experiments confirmed vitronectin production upon EV stimulation in vitro. Bacteria captured vitronectin from BALF on their surface to evade lysis by complement in serum. Hence, vitronectin is produced by epithelial cells upon bacterial infection and utilized by respiratory pathogens to persist in the respiratory tract.
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| 8. |
- Sabado, R.L., et al.
(author)
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In vitro priming recapitulates in vivo HIV-1 specific T cell responses, revealing rapid loss of virus reactive CD4+ T cells in acute HIV-1 infection
- 2009
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 4:1, s. e4256-
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Journal article (peer-reviewed)abstract
- Background: The requirements for priming of HIV-specific T cell responses initially seen in infected individuals remain to be defined. Activation of T cell responses in lymph nodes requires cell-cell contact between T cells and DCs, which can give concurrent activation of T cells and HIV transmission. Methodology: The study aim was to establish whether DCs pulsed with HIV-1 could prime HIV-specific T cell responses and to characterize these responses. Both infectious and aldrithiol-2 inactivated noninfectious HIV-1 were compared to establish efficiencies in priming and the type of responses elicited. Findings: Our findings show that both infectious and inactivated HIV-1 pulsed DCs can prime HIV-specific responses from na�ve T cells. Responses included several CD4+ and CD8+ T cell epitopes shown to be recognized in vivo by acutely and chronically infected individuals and some CD4+ T cell epitopes not identified previously. Follow up studies of acute and recent HIV infected samples revealed that these latter epitopes are among the earliest recognized in vivo, but the responses are lost rapidly, presumably through activation-induced general CD4+ T cell depletion which renders the newly activated HIV-specific CD4+ T cells prime targets for elimination. Conclusion: Our studies highlight the ability of DCs to efficiently prime na�ve T cells and induce a broad repertoire of HIV-specific responses and also provide valuable insights to the pathogenesis of HIV-1 infection in vivo.
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| 9. |
- Salim, Sa'ad Yislam, 1977-, et al.
(author)
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T-cell expansion capacity of Dendritic cells isolated from patients wiht Chron's disease
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Other publication (other academic/artistic)abstract
- Aphtoid lesions at the follicle-associated epithelium (FAE) are one of the earliest observable signs of recurrent ileal Crohn’s disease (CD). In an earlier study, we found an abnormal accumulation of dendritic cells (DCs) situated beneath the FAE, in the sub-epithelial dome (SED) of patients with CD. These DCs were prone to E.coli uptake. The aim here was to isolate and characterise DCs from patients with CD and determine their functional properties in T-cell expansion. Initially, DCs were isolated from eleal mucosa and blood of 5 CD patients and 5 patients with non-IBD disorders, via magnetic bead separation. DCs were also isolated from blood of 5 patients in long-term remission and 5 healthy volunteers, via FACS sorting and separation. Mixed lymphocyte reaction was performed on the isolated DCs and expansion of T-cells was recorded. DCs that were isolated from blood were also characterised via FACS analysis. DCs from patients with active CD had the tendency of having lower T-cell expansion capacity than DCs from non-IBD controls. The capacity to stimulate T-cells proliferation was restored to similar levels as healthy controls in DCs isolated from patients in remission. However, there was more than 10-fold increase in myeloid (CD11c+) DCs present in the peripheral blood mononuclear cells of CD than in healthy controls. The myeloid DCs were primarily immature (CD83-) and expressed the lymph node migratory receptor CCR7. This population of DCs may be responsible for inducing a tolerogenic or regulatory effect. Our results hint to a complex immune-regulatory mechanism where DCs at different stages of chronic inflammation exert different immune-modulatory effects.
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| 10. |
- Shankar, Esakimuthu, et al.
(author)
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Expression of a Broad Array of Negative Costimulatory Molecules and Blimp-1 in T Cells following Priming by HIV-1 Pulsed Dendritic Cells
- 2011
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In: MOLECULAR MEDICINE. - : Feinstein Institute for Medical Research. - 1076-1551 .- 1528-3658. ; 17:3-4, s. 229-240
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Journal article (peer-reviewed)abstract
- Accumulating evidence indicates that immune impairment in persistent viral infections could lead to T-cell exhaustion. To evaluate the potential contribution of induction of negative costimulatory molecules to impaired T-cell responses, we primed naive T cells with mature monocyte-derived dendritic cells (MDDCs) pulsed with HIV-1 in vitro. We used quantitative real-time polymerase chain reaction and flow cytometry, respectively, to compare the gene and surface-protein expression profiles of naive T cells primed with HIV-pulsed or mock-pulsed DCs. We detected elevated expressions of negative costimulatory molecules, including lymphocyte activation gene-3 (LAG-3). CD160, cytolytic T-lymphocyte antigen-4 (CTLA-4). T-cell immunoglobulin mucin-containing domain-3 (TIM-3), programmed death-1 (PD-1) and TRAIL (tumor necrosis-factor-related apoptosis-inducing ligand) in T cells primed by HIV-pulsed DCs. The PD-1(+) T-cell population also coexpressed TIM-3, LAG-3, and CTLA-4. Interestingly, we also found an increase in gene expression of the transcriptional repressors Blimp-1 (B-lymphocyte-induced maturation protein-1) and Foxp3 (forkhead transcription factor) in T-cells primed by HIV-pulsed DCs; Blimp-1 expression was directly proportional to the expression of the negative costimulatory molecules. Furthermore, levels of the effector cytokines interleukin-2, tumor necrosis factor-alpha and interferon-gamma, and perforin and granzyme B were decreased in T-cell populations primed by HIV-pulsed DCs. In conclusion, in vitro priming of halve T-cells with HIV-pulsed DC leads to expansion of T cells with coexpression of a broad array of negative costimulatory mclecules and Blimp-1, with potential deleterious consequences for T-cell responses.
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