1.
Bergman, Petra, et al.
(författare)
Next-generation sequencing identifies microRNAs that associate with pathogenic autoimmune neuroinflammation in rats.
2013
Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 190:8, s. 4066-75
Tidskriftsartikel (refereegranskat) abstract
MicroRNAs (miRNAs) are known to regulate most biological processes and have been found dysregulated in a variety of diseases, including multiple sclerosis (MS). In this study, we characterized miRNAs that associate with susceptibility to develop experimental autoimmune encephalomyelitis (EAE) in rats, a well-established animal model of MS. Using Illumina next-generation sequencing, we detected 544 miRNAs in the lymph nodes of EAE-susceptible Dark Agouti and EAE-resistant Piebald Virol Glaxo rats during immune activation. Forty-three miRNAs were found differentially expressed between the two strains, with 81% (35 out of 43) showing higher expression in the susceptible strain. Only 33% of tested miRNAs displayed differential expression in naive lymph nodes, suggesting that a majority of regulated miRNAs are EAE dependent. Further investigation of a selected six miRNAs indicates differences in cellular source and kinetics of expression. Several of the miRNAs, including miR-146a, miR-21, miR-181a, miR-223, and let-7, have previously been implicated in immune system regulation. Moreover, 77% (33 out of 43) of the miRNAs were associated with MS and other autoimmune diseases. Target genes likely regulated by the miRNAs were identified using computational predictions combined with whole-genome expression data. Differentially expressed miRNAs and their targets involve functions important for MS and EAE, such as immune cell migration through targeting genes like Cxcr3 and cellular maintenance and signaling by regulation of Prkcd and Stat1. In addition, we demonstrated that these three genes are direct targets of miR-181a. Our study highlights the impact of multiple miRNAs, displaying diverse kinetics and cellular sources, on development of pathogenic autoimmune inflammation.
2.
Chamorro, Clara I, et al.
(författare)
The human antimicrobial peptide LL-37 suppresses apoptosis in keratinocytes.
2009
Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 129:4, s. 937-44
Tidskriftsartikel (refereegranskat) abstract
The human cathelicidin antimicrobial peptide LL-37 is involved in various aspects of skin biology, including protection against infection, wound healing, and also in psoriasis. The tight regulation of apoptosis is critical in tissue repair and its deregulation is a part of the psoriasis phenotype. Despite being involved in cell death of several cell types, virtually nothing is known about the function of LL-37 in keratinocyte apoptosis. Here we report that LL-37 peptide protects primary human keratinocytes and HaCaT cells from apoptosis induced by the topoisomerase I inhibitor camptothecin (CAM). In particular, pretreatment with LL-37 significantly decreased caspase-3 activity after CAM-treatment. Expression profiling of keratinocytes treated with LL-37 identified the upregulation of cyclooxygenase-2 (COX-2) expression, a gene implicated in protection from apoptosis. In addition to inducing COX-2 expression, LL-37 stimulated the production of its product, prostaglandin E-2 (PGE-2). Moreover, LL-37 induced the expression of inhibitor of apoptosis-2 (IAP-2), implicated in the COX-2/PGE-2 antiapoptotic pathway. Pretreatment with a selective COX-2 inhibitor abolished the antiapoptotic effect of LL-37 and reduced IAP-2 expression implicating that the antiapoptotic effect of LL-37 in keratinocytes is mediated by a COX-2-dependent mechanism involving IAP-2. Thus, overexpression of LL-37 may contribute to reduced keratinocyte apoptosis in conditions such as psoriasis.
3.
Fekete, Tünde, et al.
(författare)
Constraints for monocyte-derived dendritic cell functions under inflammatory conditions.
2012
Ingår i: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 42:2, s. 458-69
Tidskriftsartikel (refereegranskat) abstract
The activation of TLRs expressed by macrophages or DCs, in the long run, leads to persistently impaired functionality. TLR signals activate a wide range of negative feedback mechanisms; it is not known, however, which of these can lead to long-lasting tolerance for further stimulatory signals. In addition, it is not yet understood how the functionality of monocyte-derived DCs (MoDCs) is influenced in inflamed tissues by the continuous presence of stimulatory signals during their differentiation. Here we studied the role of a wide range of DC-inhibitory mechanisms in a simple and robust model of MoDC inactivation induced by early TLR signals during differentiation. We show that the activation-induced suppressor of cytokine signaling 1 (SOCS1), IL-10, STAT3, miR146a and CD150 (SLAM) molecules possessed short-term inhibitory effects on cytokine production but did not induce persistent DC inactivation. On the contrary, the LPS-induced IRAK-1 downregulation could alone lead to persistent MoDC inactivation. Studying cellular functions in line with the activation-induced negative feedback mechanisms, we show that early activation of developing MoDCs allowed only a transient cytokine production that was followed by the downregulation of effector functions and the preservation of a tissue-resident non-migratory phenotype.
4.
Garaczi, Edina, et al.
(författare)
Negative regulatory effect of histamine in DNFB-induced contact hypersensitivity.
2004
Ingår i: International Immunology. - : Oxford University Press (OUP). - 0953-8178 .- 1460-2377. ; 16:12, s. 1781-8
Tidskriftsartikel (refereegranskat) abstract
Histamine plays an important role in the regulation of various immunological functions. To evaluate the role of histamine in contact hypersensitivity, contact dermatitis was induced with dinitrofluorobenzene (DNFB) in histidine decarboxylase knockout (HDC-/-) histamine-deficient and wild-type mice. The DNFB-induced increase of the ear thickness was significantly higher in HDC-/- mice than in wild-type mice. Using flow cytometry, significantly lower percentages of CD4+ Th and CD8+ Tc cells, and significantly higher percentages of CD45R+ B cells were observed in the regional lymph nodes in HDC-/- mice than in wild-type mice. In the ear specimens of both groups, the majority of the infiltrating cells were neutrophils and macrophages at 24 and 48 h after challenge. Using immunohistochemistry, we observed significantly more CD45+ leukocytes in HDC-/- mice than in wild-type mice. The expression of Th1 (IL-2, IFN-gamma, TNF-alpha) and Th2 (IL-4) mRNAs was examined by quantitative real time RT-PCR in the ear samples. The levels of Th1 cytokine mRNAs both at 24 and 48 h after challenge and IL-4 mRNA at 48 h showed a significantly higher increase in HDC-/- mice than in wild-type mice. These results suggest that histamine plays a negative immunoregulatory role in DNFB-induced contact hypersensitivity.
5.
Hippe, Andreas, et al.
(författare)
EGFR/Ras-induced CCL20 production modulates the tumour microenvironment.
2020
Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 123:6, s. 942-954
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND: The activation of the EGFR/Ras-signalling pathway in tumour cells induces a distinct chemokine repertoire, which in turn modulates the tumour microenvironment.METHODS: The effects of EGFR/Ras on the expression and translation of CCL20 were analysed in a large set of epithelial cancer cell lines and tumour tissues by RT-qPCR and ELISA in vitro. CCL20 production was verified by immunohistochemistry in different tumour tissues and correlated with clinical data. The effects of CCL20 on endothelial cell migration and tumour-associated vascularisation were comprehensively analysed with chemotaxis assays in vitro and in CCR6-deficient mice in vivo.RESULTS: Tumours facilitate progression by the EGFR/Ras-induced production of CCL20. Expression of the chemokine CCL20 in tumours correlates with advanced tumour stage, increased lymph node metastasis and decreased survival in patients. Microvascular endothelial cells abundantly express the specific CCL20 receptor CCR6. CCR6 signalling in endothelial cells induces angiogenesis. CCR6-deficient mice show significantly decreased tumour growth and tumour-associated vascularisation. The observed phenotype is dependent on CCR6 deficiency in stromal cells but not within the immune system.CONCLUSION: We propose that the chemokine axis CCL20-CCR6 represents a novel and promising target to interfere with the tumour microenvironment, and opens an innovative multimodal strategy for cancer therapy.
6.
Hoffmann, Thomas K, et al.
(författare)
A novel mechanism for anti-EGFR antibody action involves chemokine-mediated leukocyte infiltration.
2009
Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 124:11, s. 2589-96
Tidskriftsartikel (refereegranskat) abstract
Overexpression of the epidermal growth factor receptor (EGFR) is a hallmark of squamous cell carcinoma of the head and neck (SCCHN). Monoclonal antibodies (mAbs) against EGFR are currently used for therapy of recurrent or metastatic disease; however, their mode of action is not completely understood. To investigate the immunological effects of anti-EGFR mAb, we generated a three-dimensional spheroid model of EGFR-expressing SCCHN and used this model to study the effect of anti-EGFR mAb on leukocyte migration toward tumors. Pretreatment with the blocking anti-EGFR mAb EMD 72000, its F(ab')2 fragments or an EGFR tyrosine kinase inhibitor led to substantially increased leukocyte infiltration into EGFR overexpressing tumor spheroids, but not into those with low EGFR expression. Nonblocking anti-EGFR mAb or fibroblast-specific mAb did not affect leukocyte infiltration, suggesting that the observed increase in leukocyte infiltration depends on interference with EGFR activation. Using a human cytokine macroarray, we demonstrated that the blockade of EGFR by anti-EGFR mAb in EGFR-overexpressing SCCHN cells leads to differential expression of several cytokines and chemokines, including the chemokine MCP-1/CCL-2. The significant upregulation of MCP-1/CCL2 on exposure to anti-EGFR mAb was confirmed by quantitative PCR and enzyme-linked immunospot analyses. Moreover, blocking anti-MCP-1 antibody inhibited leukocyte migration toward tumor cells induced by anti-EGFR mAb, pointing to an important role of MCP-1/CCL2 in anti-EGFR mAb-induced leukocyte migration. Our findings demonstrate that anti-EGFR mAb induces leukocyte infiltration to tumor spheroids by upregulating chemokine expression. This novel mechanism for anti-EGFR mAb action may contribute to the antitumor effects of anti-EGFR mAb in vivo.
7.
Li, Dongqing, et al.
(författare)
MicroRNA-132 enhances transition from inflammation to proliferation during wound healing.
2015
Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 125:8, s. 3008-26
Tidskriftsartikel (refereegranskat) abstract
Wound healing is a complex process that is characterized by an initial inflammatory phase followed by a proliferative phase. This transition is a critical regulatory point; however, the factors that mediate this process are not fully understood. Here, we evaluated microRNAs (miRs) in skin wound healing and characterized the dynamic change of the miRNome in human skin wounds. miR-132 was highly upregulated during the inflammatory phase of wound repair, predominantly expressed in epidermal keratinocytes, and peaked in the subsequent proliferative phase. TGF-β1 and TGF-β2 induced miR-132 expression in keratinocytes, and transcriptome analysis of these cells revealed that miR-132 regulates a large number of immune response- and cell cycle-related genes. In keratinocytes, miR-132 decreased the production of chemokines and the capability to attract leukocytes by suppressing the NF-κB pathway. Conversely, miR-132 increased activity of the STAT3 and ERK pathways, thereby promoting keratinocyte growth. Silencing of the miR-132 target heparin-binding EGF-like growth factor (HB-EGF) phenocopied miR-132 overexpression in keratinocytes. Using mouse and human ex vivo wound models, we found that miR-132 blockade delayed healing, which was accompanied by severe inflammation and deficient keratinocyte proliferation. Together, our results indicate that miR-132 is a critical regulator of skin wound healing that facilitates the transition from the inflammatory to the proliferative phase.
8.
Li, Dongqing, et al.
(författare)
MicroRNA-31 Promotes Skin Wound Healing by Enhancing Keratinocyte Proliferation and Migration.
2015
Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 135:6, s. 1676-1685
Tidskriftsartikel (refereegranskat) abstract
Wound healing is a basic biological process restoring the integrity of the skin. The role of microRNAs during this process remains largely unexplored. By using an in vivo human skin wound healing model, we show here that the expression of miR-31 is gradually upregulated in wound edge keratinocytes in the inflammatory (1 day after injury) through the proliferative phase (7 days after injury) in comparison with intact skin. In human primary keratinocytes, overexpression of miR-31 promoted cell proliferation and migration, whereas inhibition of miR-31 had the opposite effects. Moreover, we identified epithelial membrane protein 1 (EMP-1) as a direct target of miR-31 in keratinocytes. The expression of EMP-1 in the skin was negatively correlated with the level of miR-31 during wound healing. Silencing of EMP-1 mimicked the effects of overexpression of miR-31 on keratinocyte proliferation and migration, indicating that EMP-1 is a critical target mediating the functions of miR-31 in keratinocytes. Finally, we demonstrated that transforming growth factor-β2, which is highly expressed in skin wounds, upregulated miR-31 expression in keratinocytes. Collectively, we identify miR-31 as a key regulator for promoting keratinocyte proliferation and migration during wound healing.
9.
Li, Dongqing, et al.
(författare)
miR-19a/b and miR-20a promote wound healing by regulating the inflammatory response of keratinocytes
2021
Ingår i: Journal of Investigative Dermatology. - : Elsevier. - 0022-202X .- 1523-1747. ; 141:3, s. 659-671
Tidskriftsartikel (refereegranskat) abstract
Persistent and impaired inflammation impedes tissue healing and is characteristic of chronic wounds. A better understanding of the mechanisms controlling wound inflammation is needed. Here we show that in human wound-edge keratinocytes, the expression of miR-17, miR-18a, miR-19a, miR-19b, and miR-20a, which all belong to the miR-17∼92 cluster, is upregulated during wound repair. However, their levels are lower in chronic ulcers than acute wounds at the proliferative phase. Conditional knockout of miR-17∼92 in keratinocytes as well as injection of miR-19a/b and miR-20a antisense inhibitors into wound-edges enhanced inflammation and delayed wound closure in mice. In contrast, conditional overexpression of the miR-17∼92 cluster or miR-19b alone in mice keratinocytes accelerated wound closure in vivo. Mechanistically, miR-19a/b and miR-20a decreased TLR3-mediated NF-κB activation by targeting SHCBP1 and SEMA7A, respectively, reducing the production of inflammatory chemokines/cytokines by keratinocytes. Thus, as crucial regulators of wound inflammation, lack of miR-19a/b and miR-20a may contribute to sustained inflammation and impaired healing in chronic wounds. In line with this, we show that a combinatory treatment with miR-19b and miR-20a improved wound healing in a mouse model of type 2 diabetes.
10.
Meisgen, Florian, et al.
(författare)
Activation of toll-like receptors alters the microRNA expression profile of keratinocytes.
2014
Ingår i: Experimental dermatology. - : Wiley. - 0906-6705 .- 1600-0625. ; 23:4, s. 281-3
Tidskriftsartikel (refereegranskat) abstract
Keratinocytes recognize invading pathogens by various receptors, among them Toll-like receptors (TLRs), and provide the first line of defense in skin immunity. The role of microRNAs in this important defense mechanism has not been explored yet. Our aim was to identify microRNAs involved in the innate immune response of keratinocytes. MicroRNA expression profiling revealed that the TLR2 ligand zymosan, the TLR3 ligand poly(I:C) or the TLR5 ligand flagellin significantly altered the microRNA expression in keratinocytes. The regulation of microRNAs was concentration-dependent and it could be neutralized by siRNAs specific for TLR2, TLR3 and TLR5, respectively, confirming the specificity of the TLR response. Interestingly, one microRNA, miR-146a, was strongly induced by all studied TLR ligands, while other microRNAs were regulated in a TLR- or time point-specific manner. These findings suggest an important role for microRNAs in the innate immune response of keratinocytes and provide a basis for further investigations.
