| 1. |
- Li, Dongqing, et al.
(författare)
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MicroRNA-132 enhances transition from inflammation to proliferation during wound healing.
- 2015
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Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 125:8, s. 3008-26
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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.
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| 2. |
- Li, Dongqing, et al.
(författare)
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MicroRNA-31 Promotes Skin Wound Healing by Enhancing Keratinocyte Proliferation and Migration.
- 2015
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 135:6, s. 1676-1685
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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.
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| 3. |
- Lohcharoenkal, Warangkana, et al.
(författare)
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MicroRNA-203 Inversely Correlates with Differentiation Grade, Targets c-MYC, and Functions as a Tumor Suppressor in cSCC.
- 2016
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 136:12, s. 2485-2494
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Tidskriftsartikel (refereegranskat)abstract
- Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer and a leading cause of cancer mortality among solid organ transplant recipients. MicroRNAs (miR) are short RNAs that regulate gene expression and cellular functions. Here, we show a negative correlation between miR-203 expression and the differentiation grade of cSCC. Functionally, miR-203 suppressed cell proliferation, cell motility, and the angiogenesis-inducing capacity of cSCC cells in vitro and reduced xenograft tumor volume and angiogenesis in vivo. Transcriptomic analysis of cSCC cells with ectopic overexpression of miR-203 showed dramatic changes in gene networks related to cell cycle and proliferation. Transcription factor enrichment analysis identified c-MYC as a hub of miR-203-induced transcriptomic changes in squamous cell carcinoma. We identified c-MYC as a direct target of miR-203. Overexpression of c-MYC in rescue experiments reversed miR-203-induced growth arrest in cSCC, which highlights the importance of c-MYC within the miR-203-regulated gene network. Together, miR-203 acts as a tumor suppressor in cSCC, and its low expression can be a marker for poorly differentiated tumors. Restoration of miR-203 expression may provide a therapeutic benefit, particularly in poorly differentiated cSCC.
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| 4. |
- Meisgen, Florian, et al.
(författare)
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Activation of toll-like receptors alters the microRNA expression profile of keratinocytes.
- 2014
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Ingår i: Experimental dermatology. - : Wiley. - 0906-6705 .- 1600-0625. ; 23:4, s. 281-3
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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.
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| 5. |
- Meisgen, Florian
(författare)
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MicroRNAs in skin immunity and psoriasis
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The skin protects the organism from the environment and shields it from the constant danger of infections by microorganisms. Keratinocytes are epithelial cells in the skin that constitute a physical barrier towards the environment. More than that, they are essential players in innate immunity: Keratinocytes can recognize invading pathogens by a variety of receptors, among them Toll-like receptors (TLRs). Activation of keratinocytes by pathogenic triggers leads to the induction of an inflammatory reaction in the skin, finally leading to the destruction and elimination of the pathogens. After clearance of the infection, homeostasis needs to be restored in order to avoid pathophysiological chronic inflammation. Psoriasis is a common chronic inflammatory skin disease characterized by local and systemic activation of both the innate and the adaptive immune system. In psoriasis skin lesions, hyperproliferation and activation of keratinocytes is combined with a massive infiltration of immune cells into the skin. MicroRNAs are endogenous short RNA molecules that regulate gene expression at the posttranscriptional level. They have been shown to be involved in the regulation of all basic biological processes. The aim of this thesis was to study the role of microRNAs in skin immunity, with a focus on their regulation and function in keratinocytes under homeostatic and inflammatory conditions. We have characterized systematically the microRNA expression profile of keratinocytes treated with ligands for TLR2, TLR5 and TLR3, showing that a distinct subset of microRNAs is regulated by different TLR ligands (Paper I). MiR-146a was strongly induced by all studied TLR ligands, while other microRNAs were regulated in a TLR- or time pointspecific manner. A detailed analysis of the regulation of miR-146a in keratinocytes revealed its long-lasting induction upon TLR2 stimulation, leading to a global repression of the inflammatory response (Paper II). Functionally, miR-146a acts as a negative feedback to counteract TLR2-induced inflammation and to restore tissue homeostasis by suppressing the production of inflammatory mediators and the chemotactic attraction of immune cells. Moreover, endogenous miR-146a was essential to prevent unstimulated keratinocytes from producing inflammatory mediators, thus protecting from unwanted inflammation in the absence of a trigger. In the chronically inflamed skin of psoriasis patients, miR-146a was overexpressed and keratinocytes were partially responsible for this phenotype (Paper III). Pro-inflammatory cytokines of the IL-1 family were shown to be strong inducers of miR-146a, plausibly responsible for the miR-146a overexpression in psoriasis keratinocytes. Taken together, these results propose that miR-146a regulates skin immune responses after infection or skin injury and may set the threshold of activation in keratinocytes. We have identified miR-31 as another microRNA overexpressed in psoriasis keratinocytes and regulating the keratinocyte immune responses (Paper IV). MiR-31 could be induced by TGF-β1 in vitro and in vivo. Inhibition of endogenous miR-31 decreased the inflammatory activity of keratinocytes, suggesting that miR-31 acts as a pro-inflammatory microRNA and contributes to the chronic inflammation in psoriasis lesions. In conclusion, the data presented in this thesis underline the crucial importance of microRNAs in the innate immune response of keratinocytes. The modulation of the local inflammatory environment by microRNAs may explain more of the unknown underlying factors regulating susceptibility to autoimmune diseases such as psoriasis.
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| 6. |
- Meisgen, Florian, et al.
(författare)
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MiR-146a negatively regulates TLR2-induced inflammatory responses in keratinocytes.
- 2014
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Ingår i: Journal of Investigative Dermatology. - : Elsevier BV. - 0022-202X .- 1523-1747. ; 134:7, s. 1931-1940
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Tidskriftsartikel (refereegranskat)abstract
- Keratinocytes represent the first line of defense against pathogens in the skin and have important roles in initiating and regulating inflammation during infection and autoimmunity. Here we investigated the role of miR-146a in the regulation of the innate immune response of keratinocytes. Toll-like receptor 2 (TLR2) stimulation of primary human keratinocytes resulted in an NF-κB- and mitogen-activated protein kinase-dependent upregulation of miR-146a expression, which was surprisingly long lasting, contrasting with the rapid and transient induction of inflammatory mediators. Overexpression of miR-146a significantly suppressed the production of IL-8, CCL20, and tumor necrosis factor-α, which functionally suppressed the chemotactic attraction of neutrophils by keratinocytes. Inhibition of endogenous miR-146a induced the production of inflammatory mediators even in nonstimulated keratinocytes, and potentiated the effect of TLR2 stimulation. Transcriptomic profiling revealed that miR-146a suppresses the expression of a large number of immune-related genes in keratinocytes. MiR-146a downregulated interleukin-1 receptor-associated kinase 1 and TNF receptor-associated factor 6, two key adapter molecules downstream of TLR signaling, and suppressed NF-κB promoter-binding activity as shown by promoter luciferase experiments. Together, these data identify miR-146a as a regulatory element in keratinocyte innate immunity, which prevents the production of inflammatory mediators under homeostatic conditions and serves as a potent negative feedback regulator after TLR2 stimulation.
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| 7. |
- Meisgen, Florian, et al.
(författare)
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MiR-21 is up-regulated in psoriasis and suppresses T cell apoptosis.
- 2012
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Ingår i: Experimental dermatology. - : Wiley. - 0906-6705 .- 1600-0625. ; 21:4, s. 312-4
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Tidskriftsartikel (refereegranskat)abstract
- MicroRNAs are short non-coding RNAs that regulate gene expression. Previously, in a genome-wide screen, we found deregulation of microRNA expression in psoriasis skin. MicroRNA-21 (miR-21) is one of the microRNAs significantly up-regulated in psoriasis skin lesions. To identify the cell type responsible for the increased miR-21 level, we compared expression of miR-21 in epidermal cells and dermal T cells between psoriasis and healthy skin and found elevated levels of miR-21 in psoriasis in both cell types. In cultured T cells, expression of miR-21 increased markedly upon activation. To explore the function of miR-21 in primary human T helper cells, we inhibited miR-21 using a tiny seed-targeting LNA-anti-miR. Specific inhibition of miR-21 increased the apoptosis rate of activated T cells. Our results suggest that miR-21 suppresses apoptosis in activated T cells, and thus, overexpression of miR-21 may contribute to T cell-derived psoriatic skin inflammation.
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| 8. |
- Pasquali, Lorenzo, et al.
(författare)
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The Keratinocyte Transcriptome in Psoriasis : Pathways Related to Immune Responses, Cell Cycle and Keratinization.
- 2019
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 99:2, s. 196-205
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Tidskriftsartikel (refereegranskat)abstract
- Psoriasis is a common immune-mediated disease resulting from altered cross-talk between keratinocytes and immune cells. Previous transcriptomic studies have identified thousands of deregulated genes in psoriasis skin; however, the transcriptomic changes confined to the epidermal compartment remained poorly characterized. The aim of this study was to characterize the transcriptomic landscape of psoriatic keratinocytes, using sorted CD45neg epidermal cells. Genes with functions in innate immunity, type I interferon response, cell cycle and keratinization were enriched among deregulated genes in psoriatic keratinocytes. Gene set enrichment analysis indicated the dominance of interleukin (IL)-22/IL-17A signatures in the epidermal psoriasis-signature. A set of deregulated genes overlapped with psoriasis-associated genetic regions, suggesting that genetic variations affecting gene expression in keratinocytes contribute to susceptibility to psoriasis. Several psoriasis-susceptibility genes, which were previously believed to be expressed preferentially or exclusively in immune cells, were identified as having altered expression in psoriatic keratinocytes. These results highlight the role of keratinocytes in the pathogenesis of psoriasis, and indicate that both genetic factors and an inflammatory microenvironment contribute to epidermal alterations in psoriasis.
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| 9. |
- Sonkoly, Enikö, et al.
(författare)
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MiR-155 is overexpressed in patients with atopic dermatitis and modulates T-cell proliferative responses by targeting cytotoxic T lymphocyte-associated antigen 4.
- 2010
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier BV. - 0091-6749 .- 1097-6825. ; 126:3, s. 581-9.e1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: MicroRNAs (miRNAs) are short noncoding RNAs that suppress gene expression at the posttranscriptional level. Atopic dermatitis is a common chronic inflammatory skin disease characterized by the presence of activated T cells within the skin.OBJECTIVE: We sought to explore the role of miRNAs in the pathogenesis of atopic dermatitis.METHODS: Global miRNA expression in healthy and lesional skin of patients with atopic dermatitis was compared by using TaqMan MicroRNA Low Density Arrays. miR-155 expression in tissues and cells was quantified by means of quantitative real-time PCR. The cellular localization of miR-155 was analyzed by means of in situ hybridization. The regulation of cytotoxic T lymphocyte-associated antigen (CTLA-4) by miR-155 was investigated by using luciferase reporter assays and flow cytometry. CTLA-4 expression and functional assays were performed on T(H) cells overexpressing miR-155.RESULTS: miR-155 was one of the highest-ranked upregulated miRNAs in patients with atopic dermatitis. In the skin miR-155 was predominantly expressed in infiltrating immune cells. miR-155 was upregulated during T-cell differentiation/activation and was markedly induced by T-cell activators in PBMCs in vitro and by superantigens and allergens in the skin in vivo. CTLA-4, an important negative regulator of T-cell activation, was identified as a direct target of miR-155. Overexpression of miR-155 in T(H) cells resulted in decreased CTLA-4 levels accompanied by an increased proliferative response.CONCLUSION: miR-155 is significantly overexpressed in patients with atopic dermatitis and might contribute to chronic skin inflammation by increasing the proliferative response of T(H) cells through the downregulation of CTLA-4.
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| 10. |
- Srivastava, Ankit, et al.
(författare)
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Cross-talk between IFN-γ and TWEAK through miR-149 amplifies skin inflammation in psoriasis
- 2021
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Ingår i: Journal of Allergy and Clinical Immunology. - : Elsevier. - 0091-6749 .- 1097-6825. ; 147:6, s. 2225-2235
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Psoriasis is a chronic inflammatory skin disease with disturbed interplay between immune cells and keratinocytes. A strong IFN-γ signature is characteristic for psoriasis skin, but the role of IFN-γ has been elusive. MicroRNAs are short RNAs regulating gene expression.OBJECTIVE: Our aim was to investigate the role of miR-149 in psoriasis and in the inflammatory responses of keratinocytes.METHODS: miR-149 expression was measured by quantitative RT-PCR in keratinocytes isolated from healthy skin and lesional and nonlesional psoriasis skin. Synthetic miR-149 was injected intradermally into the back skin of mice, and imiquimod was applied to induce psoriasis-like skin inflammation, which was then evaluated at the morphologic, histologic, and molecular levels. miR-149 was transiently overexpressed or inhibited in keratinocytes in combination with IFN-γ- and/or TNF-related weak inducer of apoptosis (TWEAK)-treatment.RESULTS: Here we report a microRNA-mediated mechanism by which IFN-γ primes keratinocytes to inflammatory stimuli. Treatment with IFN-γ results in a rapid and long-lasting suppression of miR-149 in keratinocytes. Depletion of miR-149 in keratinocytes leads to widespread transcriptomic changes and induction of inflammatory mediators with enrichment of the TWEAK pathway. We show that IFN-γ-mediated suppression of miR-149 leads to amplified inflammatory responses to TWEAK. TWEAK receptor (TWEAKR/Fn14) is identified as a novel direct target of miR-149. The in vivo relevance of this pathway is supported by decreased miR-149 expression in psoriasis keratinocytes, as well as by the protective effect of synthetic miR-149 in the imiquimod-induced mouse model of psoriasis.CONCLUSION: Our data define a new mechanism, in which IFN-γ primes keratinocytes for TWEAK-induced inflammatory responses through suppression of miR-149, promoting skin inflammation.
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