Joanna Skrzeczynska-Moncznik

Potential role of chemerin in recruitment of plasmacytoid dendritic cells to diseased skin

Interferon alpha-producing plasmacytoid dendritic cells (pDC) are crucial contributors to pro-inflammatory or tolerogenic immune responses and are important in autoimmune diseases such as psoriasis. pDC accumulate in the lesional skin of psoriasis patients, but are rarely found in the affected skin of patients with atopic dermatitis (AD). While homeostatic chemokine CXCL12 and inducible pro-inflammatory CXCR3 chemokine ligands may regulate pDC influx to psoriatic skin, the mechanism responsible for selective pDC recruitment in psoriasis vs. AD remains unknown. Circulating pDC from normal donors express a limited number of chemoattractant receptors, including CXCR3 and CMKLR1 (chemokine-like receptor 1). In this work, we demonstrate that circulating pDC from normal donors as well as psoriasis and AD patients express similar levels of CXCR3 and responded similarly in functional migration assays to CXCL10. We next found that blood pDC from normal, AD, and psoriasis patients express functional CMKLR1. In contrast to normal skin, however, lesional skin from psoriasis patients contains the active form of the CMKLR1 ligand chemerin. Furthermore, in affected skin from psoriatic patients the level of active chemerin was generally higher than in AD skin. Taken together, these results indicate that local generation of active chemerin may contribute to pDC recruitment to psoriatic skin.

Interaction of human peripheral blood monocytes with apoptotic polymorphonuclear cells

Macrophages have the potential to recognize apoptotic neutrophils and phagocytose them while the same function for monocytes is uncertain. In fact, early findings indicated that monocytes started to phagocytose neutrophils on the third day of differentiation to macrophages. Here we show, using flow cytometry and confocal microscopy, that peripheral blood monocytes phagocytose apoptotic but not freshly isolated granulocytes. Recognition of apoptotic cells is predominantly connected with CD16+ monocytes (CD14high CD16+ and CD14dim CD16+) and requires CD36. Clearance of apoptotic polymorphonuclear leucocytes appears to be independent of the CD14 mechanism. Uptake of apoptotic Jurkat T cells by monocytes is CD14 and CD36 dependent. Liposomes containing phosphatidyl‐l‐serine reduce binding of apoptotic polymorphonuclear leucocytes. Lipopolysaccharide‐activated subpopulations of monocytes while in contact with apoptotic cells produce more anti‐inflammatory cytokine interleukin‐10 whereas the production of pro‐inflammatory cytokines, tumour necrosis factor‐α and interleukin‐1β is reduced.

Secretory Leukocyte Proteinase Inhibitor-Competent DNA Deposits Are Potent Stimulators of Plasmacytoid Dendritic Cells: Implication for Psoriasis

Secretory leukocyte proteinase inhibitor (SLPI) is a well-established inhibitor of serine proteases such as human neutrophil elastase (HNE) and a NF-κB regulatory agent in immune cells. In this paper, we report that SLPI plays a previously uncharacterized role in regulating activation of plasmacytoid dendritic cells (pDCs). As the main source of IFN type I (IFNI), pDCs are crucial contributors to inflammatory and likely wound-healing responses associated with psoriasis. The mechanisms responsible for activation of pDCs in psoriatic skin are therefore of substantial interest. We demonstrate that in lesional skin of psoriasis patients, SLPI together with its enzymatic target HNE and DNA, is a component of neutrophil extracellular traps (NETs). Whereas SLPI+ neutrophils and NETs were found to colocalize with pDCs in psoriatic skin, a mixture of SLPI with neutrophil DNA and HNE induced a marked production of IFNI by pDCs. IFNI synthesis by stimulated pDCs was dependent on intracellular DNA receptor TLR9. Thus, SLPI may contribute to psoriasis by enabling pDCs to sense extracellular DNA and produce IFNI.

Oxidized LDLs Inhibit TLR-induced IL-10 Production by Monocytes: A New Aspect of Pathogen-Accelerated Atherosclerosis

It is widely accepted that oxidized low-density lipoproteins and local infections or endotoxins in circulation contribute to chronic inflammatory process at all stages of atherosclerosis. The hallmark cells of atherosclerotic lesions—monocytes and macrophages—are able to detect and integrate complex signals derived from lipoproteins and pathogens, and respond with a spectrum of immunoregulatory cytokines. In this study, we show strong inhibitory effect of oxLDLs on anti-inflammatory interleukin-10 production by monocytes responding to TLR2 and TLR4 ligands. In contrast, pro-inflammatory tumor necrosis factor secretion was even slightly increased, when stimulated with lipopolysaccharide from Porphyromonas gingivalis—an oral pathogen associated with atherosclerosis. The oxLDLs modulatory activity may be explained by altered recognition of pathogen-associated molecular patterns, which involves serum proteins, particularly vitronectin. We also suggest an interaction between vitronectin receptor, CD11b, and TLR2. The presented data support a novel pathway for pathogen-accelerated atherosclerosis, which relies on oxidized low-density lipoprotein-mediated modulation of anti-inflammatory response to TLR ligands.

Inhibitors of Serine Proteases in Regulating the Production and Function of Neutrophil Extracellular Traps

Neutrophil extracellular traps (NETs), DNA webs released into the extracellular environment by activated neutrophils, are thought to play a key role in the entrapment and eradication of microbes. However, NETs are highly cytotoxic and a likely source of autoantigens, suggesting that NET release is tightly regulated. NET formation involves the activity of neutrophil elastase (NE), which cleaves histones, leading to chromatin decondensation. We and others have recently demonstrated that inhibitors of NE, such as secretory leukocyte protease inhibitor (SLPI) and SerpinB1, restrict NET production in vitro and in vivo. SLPI was also identified as a NET component in the lesional skin of patients suffering from the autoinflammatory skin disease psoriasis. SLPI-competent NET-like structures (a mixture of SLPI with neutrophil DNA and NE) stimulated the synthesis of interferon type I (IFNI) in plasmacytoid dendritic cells (pDCs) in vitro. pDCs uniquely respond to viral or microbial DNA/RNA but also to nucleic acids of “self” origin with the production of IFNI. Although IFNIs are critical in activating the antiviral/antimicrobial functions of many cells, IFNIs also play a role in inducing autoimmunity. Thus, NETs decorated by SLPI may regulate skin immunity through enhancing IFNI production in pDCs. Here, we review key aspects of how SLPI and SerpinB1 can control NET production and immunogenic function.

Triterpene saponosides from Lysimachia ciliata differentially attenuate invasive potential of prostate cancer cells.

Neither androgen ablation nor chemotherapeutic agents are effective in reducing the risk of prostate cancer progression. On the other hand, multifaceted effects of phytochemicals, such as triterpene saponins, on cancer cells have been suggested. A promising safety and tolerability profile indicate their possible application in the treatment of advanced prostate cancers. We analyzed the specificity, selectivity and versatility of desglucoanagalloside B effects on human prostate cancer cells derived from prostate cancer metastases to brain (DU-145 cells) and bone (PC-3 cells). Prominent growth arrest and apoptotic response of both cell types was observed in the presence of sub-micromolar desglucoanagalloside B concentrations. This was accompanied by cytochrome c release and caspase 3/7 activation. A relatively low cytostatic and pro-apoptotic response of cancer cells to a desglucoanagalloside B analog, anagallosaponin IV, illustrated the specificity of the effects of desglucoanagalloside B, whereas the low sensitivity of normal prostate PNT2 cells to desglucoanagalloside B showed the selectivity of its action. Inhibition of cancer cell motility was observed in the presence of both saponins, however only desglucoanagalloside B attenuated cancer cell invasive potential, predominantly through an effect on cell elastic properties. These data demonstrate the versatility of its effects on prostate cancer cells. In contrast to PNT2 cells, cancer cells tested in this study were relatively resistant to mitoxantrone. The multifaceted action of desglucoanagalloside B on basic cellular traits, crucial for prostate cancer progression, opens perspectives for elaboration of combined palliative therapies and new prostate cancer prophylaxis regimens.

Bradykinin and des-Arg10-kallidin enhance the adhesion of polymorphonuclear leukocytes to extracellular matrix proteins and endothelial cells

Abstract Bradykinin-related peptides (kinins) are well known to contribute to leukocyte recruitment to inflammatory foci; however, a role of these universal pro-inflammatory mediators in the first step of this process, i.e. the leukocyte adhesion to endothelial cells, is not well understood. In this work we found that bradykinin and des-Arg10-kallidin enhance the adhesion of polymorphonuclear bloods cells (PMN) to fibrinogen and fibronectin. Also, the PMN adherence to endothelial cells of HMEC-1 line strongly increased after stimulation by kinins, particularly des-Arg10-kallidin, or when PMN were co-stimulated with bradykinin and interleukin-1β. These effects were attenuated after PMN treatment with a specific inhibitor of carboxypeptidases, which convert kinins to their des-Arg metabolites. The kinin peptides were also able to change the Mac-1 integrin expression on the PMN surface. These results suggest a regulatory effect of kinins on leukocyte adhesion to endothelial wall, providing new aspects of the leukocyte infiltration into inflamed tissues.

Rapid externalization of 27‐kDa heat shock protein (HSP27) and atypical cell death in neutrophils treated with the sphingolipid analog drug FTY720

The sphingolipid analog fingolimod is known to induce apoptosis of tumor cells and lymphocytes. Its effect on neutrophils has not been investigated so far. Here, we describe a fingolimod‐induced atypical cell death mechanism in human neutrophils, characterized by rapid translocation of heat shock protein 27 to the cell surface, extensive cell swelling and vacuolization, atypical chromatin staining and nuclear morphology, and phosphorylation of mixed lineage kinase domain‐like protein. Fingolimod also induces typical apoptotic features, including rapid externalization of phosphatidylserine and activation of caspase‐8. Fingolimod‐induced neutrophil death is independent of sphingosine‐1‐phosphate receptors and positively regulated by protein phosphatase A. Externalization of phosphatidylserine and heat shock protein 27 can be partially inhibited by inhibitors of caspase‐8 [Z‐Ile‐Glu(O‐Me)‐Thr‐Asp(O‐Me)‐fluoromethyl ketone], receptor‐interacting protein kinase 1 (necrostatin‐1), receptor‐interacting protein kinase 3 (necrosulfonamide), and heat shock protein 90 [geldanamycin and 17‐(dimethylaminoethylamino)‐17‐demethoxygeldanamycin]. Furthermore, NADPH oxidase 1 inhibition with diphenyleneiodonium chloride protects neutrophils against fingolimod‐mediated cell death. Overall, these observations suggest that fingolimod acts through a mechanism involving the necrosome signaling complex and the oxidative stress machinery.