scholarly journals RNA-antimicrobial peptide LL-37 complexes fuel a TLR- and NET-mediated inflammatory cycle of neutrophil activation in psoriasis

2018 ◽  
Author(s):  
Franziska Herster ◽  
Zsofia Bittner ◽  
Sabine Dickhöfer ◽  
David Eise ◽  
Tatjana Eigenbrod ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Intervention Strategy ◽  
Skin Lesions ◽  
Neutrophil Extracellular Trap ◽  
Psoriatic Skin ◽  
Bacterial Rna ◽  
Human Pmns ◽  
Inflammatory Autoimmune Disease

AbstractPsoriasis is an inflammatory autoimmune disease characterized by skin lesions showing strong neutrophil (PMN) infiltration and high levels of the antimicrobial peptide, LL37, but the role of PMNs in this context remains unclear. We here show that primary human PMNs, especially PMNs from psoriasis patients, not only respond via TLR8 to human and bacterial RNA in complexed with LL37 by cytokine-, chemokine- and neutrophil extracellular trap (NET)-release; they also actively release additional RNA and LL37 in response to stimulation by the same complex and both RNA and LL37 were found to be highly abundant in psoriatic skin. Moreover, RNA-LL37-induced NETs propagated PMN activation and could thus fuel a PMN-mediated and self-sustaining inflammatory loop that may represent an unexpected early initiator or amplifying event in psoriasis. Given that TLR inhibitory oligodeoxynucleotides prevented the cytokine production and NETosis of PMNs by RNA-LL37 complexes in vitro, our study also highlights TLR blockade as a potential therapeutic intervention strategy in psoriasis.SummaryHuman and bacterial RNA in complex with LL37 activates neutrophils via TLR8 to release cytokines, chemokines and neutrophil extracellular traps (NETs). NETs and neutrophil-rich areas in psoriatic skin contain RNA and LL37, suggesting RNA-LL37 may fuel a PMN-mediated and self-sustaining inflammatory cycle in psoriasis.

scholarly journals miR-155 Contributes to Normal Keratinocyte Differentiation and Is Upregulated in the Epidermis of Psoriatic Skin Lesions

2020 ◽  
Vol 21 (23) ◽  
pp. 9288
Author(s):  
Lucian Beer ◽  
Polina Kalinina ◽  
Martin Köcher ◽  
Maria Laggner ◽  
Markus Jeitler ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Normal Skin ◽  
Skin Lesions ◽  
Keratinocyte Differentiation ◽  
Psoriatic Skin ◽  
Bioinformatics Analyses ◽  
Epidermal Barrier ◽  
Barrier Formation

The role of microRNAs (miRNAs) during keratinocyte (KC) differentiation and in skin diseases with epidermal phenotypes has attracted strong interest over the past few years. However, combined mRNA and miRNA expression analyses to elucidate the intricate mRNA–miRNA networks of KCs at different stages of differentiation have not been performed yet. In the present study, we investigated the dynamics of miRNA and mRNA expression during KC differentiation in vitro and in normal and psoriatic epidermis. While we identified comparable numbers of up- and downregulated mRNAs (49% and 51%, respectively), miRNAs were predominantly upregulated (76% vs 24%) during KC differentiation. Further bioinformatics analyses suggested an important inhibitory role for miR-155 in KC differentiation, as it was repressed during KC differentiation in normal skin but strongly upregulated in the epidermis of psoriatic skin lesions. Mimicking the inflammatory milieu of psoriatic skin in vitro, we could show that the pro-inflammatory cytokines IL17, IL1β and INFγ synergistically upregulated miR-155 expression in KCs. Forced over-expression of miR-155 in human in vitro skin models specifically reduced the expression of loricrin (LOR) in KCs, indicating that miR-155 interferes with the establishment of a normal epidermal barrier. Together, our data indicate that downregulation of miR-155 during KC differentiation is a crucial step for epidermal barrier formation. Furthermore, its strong upregulation in psoriatic lesions suggests a contributing role of miR-155 in the altered keratinocyte differentiation observed in psoriasis. Therefore, miR-155 represents as a potential target for treating psoriatic skin lesions.

scholarly journals LncRNA MEG3 influences the proliferation and apoptosis of psoriasis epidermal cells by targeting miR-21/caspase-8

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Hai-Yan Jia ◽  
Kai Zhang ◽  
Wen-Jing Lu ◽  
Gui-Wen Xu ◽  
Jian-Fen Zhang ◽  
...  
Keyword(s):  
Binding Site ◽  
Cell Model ◽  
Mrna Level ◽  
Epidermal Cells ◽  
Luciferase Reporter ◽  
Psoriatic Skin ◽  
Caspase 8 ◽  
Proliferation And Apoptosis

Abstract Background It was reported that microRNA-21(miR-21) was differentially expressed in the keratinocytes of psoriasis patients, and it may influence the apoptosis and proliferation of cells. The role of lncRNA maternally expressed gene3 (MEG3), a competing endogenous RNAs of miR-21, in the progression of psoriasis remains unclear. We aimed to unfold the influence of MEG3 and miR-21 on the proliferation and apoptosis of psoriasis epidermal cells. Methods 50μg/L TNF-α was used to treat HaCaTs and NHEKs cells for 24 h, and then different experiments were conducted. qRT-PCR were applied for measuring the mRNA level of MEG3, miR-2, and caspase-8, and the protein expression of caspase-8 was measured with western blotting. Flow cytometry was used for assessing apoptosis. Cell proliferation was detected using MTT and colony formation assays. Dual luciferase reporter assay was applied for confirming the binding site between MEG3 and miR-21, miR-21 and Caspase-8. Results A cell model for in vitro studying the role of MEG3 in psoriasis pathophysiology was established using HaCaT and HHEKs. MEG3 was significantly down-regulated in HaCaT, HHEKs, and psoriatic skin samples. MEG3 inhibits proliferation and promotes apoptosis of Activated-HaCaT (Act-HaCaT) and Activated-HHEKs (Act- HHEK) by regulating miR-21, and the binding site between MEG3 and miR-21 was identified. We also found that miR-21 could inhibit the level of caspase-8 and identified the binding site between caspase-8 and miR-21. Some down-stream proteins of caspase-8, Cleaved caspase-8, cytc, and apaf-1 were regulated by miR-21 and MEG3. Conclusion MEG3/miR-21 axis may regulate the expression of caspase-8, and further influence the proliferation and apoptosis of psoriasis keratinocyte, Act-HaCaT and Act- HHEK. Therefore, our findings may provide a new thought for the study of pathogenesis and treatment of psoriasis.

The role of telomerase activity in psoriatic skin lesions

2007 ◽  
Vol 68 (5) ◽  
pp. 1093-1095 ◽  
Author(s):  
Davor Jurisic ◽  
Ivan Kirin ◽  
Domagoj Rabic ◽  
Bojan Dojcinovic ◽  
Miran Coklo ◽  
...  
Keyword(s):  
Skin Lesions ◽  
Telomerase Activity ◽  
Psoriatic Skin

scholarly journals High Purity Isolation of Low Density Neutrophils Casts Doubt on Their Exceptionality in Health and Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Gareth R. Hardisty ◽  
Frances Llanwarne ◽  
Danielle Minns ◽  
Jonathan L. Gillan ◽  
Donald J. Davidson ◽  
...  
Keyword(s):  
High Purity ◽  
Neutrophil Extracellular Trap ◽  
Normal Density ◽  
Low Density ◽  
Inflammatory Conditions ◽  
Functional Differences ◽  
Healthy Donors ◽  
Health And Disease

Low density neutrophils (LDNs) are described in a number of inflammatory conditions, cancers and infections and associated with immunopathology, and a mechanistic role in disease. The role of LDNs at homeostasis in healthy individuals has not been investigated. We have developed an isolation protocol that generates high purity LDNs from healthy donors. Healthy LDNs were identical to healthy normal density neutrophils (NDNs), aside from reduced neutrophil extracellular trap formation. CD66b, CD16, CD15, CD10, CD54, CD62L, CXCR2, CD47 and CD11b were expressed at equivalent levels in healthy LDNs and NDNs and underwent apoptosis and ROS production interchangeably. Healthy LDNs had no differential effect on CD4+ or CD8+ T cell proliferation or IFNγ production compared with NDNs. LDNs were generated from healthy NDNs in vitro by activation with TNF, LPS or fMLF, suggesting a mechanism of LDN generation in disease however, we show neutrophilia in people with Cystic Fibrosis (CF) was not due to increased LDNs. LDNs are present in the neutrophil pool at homeostasis and have limited functional differences to NDNs. We conclude that increased LDN numbers in disease reflect the specific pathology or inflammatory environment and that neutrophil density alone is inadequate to classify discrete functional populations of neutrophils.

scholarly journals Downregulation of Microparticle Release and Pro-Inflammatory Properties of Activated Human Polymorphonuclear Neutrophils by LMW Fucoidan

2018 ◽  
Vol 11 (4) ◽  
pp. 330-346 ◽  
Author(s):  
João Alfredo Moraes ◽  
Ana Clara Frony ◽  
Pedro Barcellos-de-Souza ◽  
Marcel Menezes da Cunha ◽  
Thayanne Brasil Barbosa Calcia ◽  
...  
Keyword(s):  
Polymorphonuclear Neutrophils ◽  
In Vivo Experiments ◽  
Formyl Peptide ◽  
Human Pmns ◽  
Oxidative Effects ◽  
Species Production ◽  
Bacterial Products

Exposition of neutrophils (polymorphonuclear neutrophils, PMNs) to bacterial products triggers exacerbated activation of these cells, increasing their harmful effects on host tissues. We evaluated the possibility of interfering with the classic immune innate responses of human PMNs exposed to bacterial endotoxin (lipopolysaccharide, LPS), and further stimulated with bacterial formyl peptide (N-formyl-methionine-leucine-phenylalanine, fMLP). We showed that the low- molecular-weight fucoidan (LMW-Fuc), a polysaccharide extracted from brown algae, attenuated the exacerbated activation induced by fMLP on LPS-primed PMNs, in vitro, impairing chemotaxis, NET formation, and the pro-survival and pro-oxidative effects. LMW-Fuc also inhibited the activation of canonical signaling pathways, AKT, bad, p47phox and MLC, activated by the exposition of PMN to bacterial products. The activation of PMN by sequential exposure to LPS and fMLP induced the release of L-selectin+ microparticles, which were able to trigger extracellular reactive oxygen species production by fresh PMNs and macrophages. Furthermore, we observed that LMW-Fuc inhibited microparticle release from activated PMN. In vivo experiments showed that circulating PMN-derived microparticles could be detected in mice exposed to bacterial products (LPS/fMLP), being downregulated in animals treated with LMW-Fuc. The data highlight the autocrine and paracrine role of pro-inflammatory microparticles derived from activated PMN and demonstrate the anti-inflammatory effects of LMW-Fuc on these cells.

scholarly journals The iron–siderophore transporter FhuA is the receptor for the antimicrobial peptide microcin J25: role of the microcin Val11–Pro16 β-hairpin region in the recognition mechanism

2005 ◽  
Vol 389 (3) ◽  
pp. 869-876 ◽  
Author(s):  
Delphine Destoumieux-Garzón ◽  
Sophie Duquesne ◽  
Jean Peduzzi ◽  
Christophe Goulard ◽  
Michel Desmadril ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Size Exclusion ◽  
Receptor Interaction ◽  
Titration Calorimetry ◽  
Scanning Calorimetry ◽  
Recognition Mechanism ◽  
Microcin J25

The role of the outer-membrane iron transporter FhuA as a potential receptor for the antimicrobial peptide MccJ25 (microcin J25) was studied through a series of in vivo and in vitro experiments. The requirement for both FhuA and the inner-membrane TonB–ExbB–ExbD complex was demonstrated by antibacterial assays using complementation of an fhuA− strain and by using isogenic strains mutated in genes encoding the protein complex respectively. In addition, MccJ25 was shown to block phage T5 infection of Escherichia coli, in vivo, by inhibiting phage adhesion, which suggested that MccJ25 prevents the interaction between the phage and its receptor FhuA. This in vivo activity was confirmed in vitro, as MccJ25 inhibited phage T5 DNA ejection triggered by purified FhuA. Direct interaction of MccJ25 with FhuA was demonstrated for the first time by size-exclusion chromatography and isothermal titration calorimetry. MccJ25 bound to FhuA with a 2:1 stoichiometry and a Kd of 1.2 μM. Taken together, our results demonstrate that FhuA is the receptor for MccJ25 and that the ligand–receptor interaction may occur in the absence of other components of the bacterial membrane. Finally, both differential scanning calorimetry and antimicrobial assays showed that MccJ25 binding involves external loops of FhuA. Unlike native MccJ25, a thermolysin-cleaved MccJ25 variant was unable to bind to FhuA and failed to prevent phage T5 infection of E. coli. Therefore the Val11–Pro16 β-hairpin region of MccJ25, which is disrupted upon cleavage by thermolysin, is required for microcin recognition.

scholarly journals Characterization of Stress and Innate Immunity Resistance of Wild-Type and Δp66 Borrelia burgdorferi

2017 ◽  
Vol 86 (2) ◽  
Author(s):  
Michael W. Curtis ◽  
Beth L. Hahn ◽  
Kai Zhang ◽  
Chunhao Li ◽  
Richard T. Robinson ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Antimicrobial Peptide ◽  
Membrane Integrity ◽  
The United States ◽  
Laboratory Model ◽  
Wild Type ◽  
Content Type ◽  
Inoculation Site

ABSTRACTBorrelia burgdorferiis a causative agent of Lyme disease, the most common arthropod-borne disease in the United States.B. burgdorferievades host immune defenses to establish a persistent, disseminated infection. Previous work showed that P66-deficientB. burgdorferi(Δp66) is cleared quickly after inoculation in mice. We demonstrate that the Δp66strain is rapidly cleared from the skin inoculation site prior to dissemination. The rapid clearance of Δp66bacteria is not due to inherent defects in multiple properties that might affect infectivity: bacterial outer membrane integrity, motility, chemotactic response, or nutrient acquisition. This led us to the hypothesis that P66 has a role in mouse cathelicidin-related antimicrobial peptide (mCRAMP; a major skin antimicrobial peptide) and/or neutrophil evasion. Neither wild-type (WT) nor Δp66 B. burgdorferiwas susceptible to mCRAMP. To examine the role of neutrophil evasion, we administered neutrophil-depleting antibody anti-Ly6G (1A8) to C3H/HeN mice and subsequently monitored the course ofB. burgdorferiinfection. Δp66mutants were unable to establish infection in neutrophil-depleted mice, suggesting that the important role of P66 during early infection is through another mechanism. Neutrophil depletion did not affect WTB. burgdorferibacterial burdens in the skin (inoculation site), ear, heart, or tibiotarsal joint at early time points postinoculation. This was unexpected given that priorin vitrostudies demonstrated neutrophils phagocytose and killB. burgdorferi. These data, together with our previous work, suggest that despite thein vitroability of host innate defenses to killB. burgdorferi, individual innate immune mechanisms have limited contributions to controlling earlyB. burgdorferiinfection in the laboratory model used.

scholarly journals Self-RNA–antimicrobial peptide complexes activate human dendritic cells through TLR7 and TLR8

2009 ◽  
Vol 206 (9) ◽  
pp. 1983-1994 ◽  
Author(s):  
Dipyaman Ganguly ◽  
Georgios Chamilos ◽  
Roberto Lande ◽  
Josh Gregorio ◽  
Stephan Meller ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Inflammatory Responses ◽  
Skin Lesions ◽  
Psoriatic Skin ◽  
Cationic Antimicrobial Peptide ◽  
Tnf Α ◽  
Peptide Complexes ◽  
Human Dendritic Cells ◽  
Dying Cells

Dendritic cell (DC) responses to extracellular self-DNA and self-RNA are prevented by the endosomal seclusion of nucleic acid–recognizing Toll-like receptors (TLRs). In psoriasis, however, plasmacytoid DCs (pDCs) sense self-DNA that is transported to endosomal TLR9 upon forming a complex with the antimicrobial peptide LL37. Whether LL37 also interacts with extracellular self-RNA and how this may contribute to DC activation in psoriasis is not known. Here, we report that LL37 can bind self-RNA released by dying cells, protect it from extracellular degradation, and transport it into endosomal compartments of DCs. In pDC, self-RNA–LL37 complexes activate TLR7 and, like self-DNA–LL37 complexes, trigger the secretion of IFN-α without inducing maturation or the production of IL-6 and TNF-α. In contrast to self-DNA–LL37 complexes, self-RNA–LL37 complexes also trigger the activation of classical myeloid DCs (mDCs). This occurs through TLR8 and leads to the production of TNF-α and IL-6, and the differentiation of mDCs into mature DCs. We also found that self-RNA–LL37 complexes are present in psoriatic skin lesions and are associated with mature mDCs in vivo. Our results demonstrate that the cationic antimicrobial peptide LL37 converts self-RNA into a trigger of TLR7 and TLR8 in human DCs, and provide new insights into the mechanism that drives the auto-inflammatory responses in psoriasis.

scholarly journals A proinflammatory activity of interleukin 8 in human skin: expression of the inducible nitric oxide synthase in psoriatic lesions and cultured keratinocytes.

1996 ◽  
Vol 184 (5) ◽  
pp. 2007-2012 ◽  
Author(s):  
D Bruch-Gerharz ◽  
K Fehsel ◽  
C Suschek ◽  
G Michel ◽  
T Ruzicka ◽  
...  
Keyword(s):  
Human Keratinocytes ◽  
Skin Lesions ◽  
Psoriatic Skin ◽  
Epidermal Keratinocytes ◽  
Inos Mrna ◽  
Skin Biopsies ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Psoriasis is a common chronic skin disease mediated by cellular immune mechanisms and characterized by an intense neutrophil cell infiltrate and proliferative activation of epidermal keratinocytes. We have previously described the expression of the inducible nitric oxide synthase (iNOS) in epidermal keratinocytes of psoriatic skin lesions. In this study, the role of iNOS in psoriatic inflammation was explored ex vivo in psoriatic skin biopsies and in vitro in primary cultures of human keratinocytes. Messenger RNA for the iNOS enzyme (iNOS mRNA) was detected by reverse transcriptase polymerase chain reaction in skin biopsies from patients with psoriasis, but not in skin specimens from patients with atopic eczema or from healthy volunteers. As demonstrated by in situ hybridization and immunohistochemistry, expression of iNOS mRNA and its gene product was localized to the epidermal keratinocytes of psoriatic skin lesions. In situ hybridization further revealed a complete colocalization of mRNA expression for iNOS with interleukin (IL) 8 receptor-specific mRNA either in the basal germinative cell layer or at focal sites of ongoing neutrophil inflammation in suprabasal cell layers. Because psoriatic keratinocytes have previously been shown to express mRNA transcripts for IL-8, it seemed reasonable to hypothesize that iNOS expression could be induced in an autocrine loop by IL-8. This hypothesis was substantiated by our in vitro experiments showing that a combination of IL-8 and interferon gamma induces the expression of iNOS-specific mRNA and of the functional enzyme in cultured human keratinocytes. These results suggest an important role for iNOS in concert with IL-8 and its receptor early during the formation of psoriatic lesions.

scholarly journals Potentiation of NETs release is novel characteristic of TREM-1 activation and the pharmacological inhibition of TREM-1 could prevent from the deleterious consequences of NETs release in sepsis

2021 ◽  
Author(s):  
Amir Boufenzer ◽  
Kevin Carrasco ◽  
Lucie Jolly ◽  
Benjamin Brustolin ◽  
Elisa Di-Pillo ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Myeloid Cell ◽  
Neutrophil Extracellular Trap ◽  
Toll Like Receptor 4 ◽  
Genetic Ablation ◽  
Experimental Septic Shock ◽  
Net Release

AbstractDuring sepsis, neutrophil activation induces endothelial cell (EC) dysfunction partly through neutrophil extracellular trap (NET) release. The triggering receptor expressed on myeloid cell-1 (TREM-1) is an orphan immune receptor that amplifies the inflammatory response mediated by Toll-like receptor-4 (TLR4) engagement. Although the key role of TLR4 signaling in NETosis is known, the role of TREM-1 in this process has not yet been investigated. Here, we report that TREM-1 potentiates NET release by human and murine neutrophils and is a component of the NET structure. In contrast, pharmacologic inhibition or genetic ablation of TREM-1 decreased NETosis in vitro and during experimental septic shock in vivo. Moreover, isolated NETs were able to activate ECs and impair vascular reactivity, and these deleterious effects were dampened by TREM-1 inhibition. TREM-1 may, therefore, constitute a new therapeutic target to prevent NETosis and associated endothelial dysfunction.

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