Krzysztof Książek

Interleukin-17: a mediator of inflammatory responses

Interleukin-17 (IL-17) is a prototype member of a new cytokine family with six species identified to date. IL-17 is secreted mainly by activated CD4+ and CD8+ T lymphocytes, while its receptor is distributed ubiquitously. IL-17 has been classified as a proinflammatory cytokine because of its ability to induce the expression of many mediators of inflammation, most strikingly those that are involved in the proliferation, maturation and chemotaxis of neutrophils. Increased levels of IL-17 have been associated with several conditions, including airway inflammation, rheumatoid arthritis, intraperitoneal abscesses and adhesions, inflammatory bowel disease, allograft rejection, psoriasis, cancer and multiple sclerosis. This review provides an overview of IL-17 activities, concentrating on those that lead to neutrophil recruitment.

Oxidative stress-mediated early senescence contributes to the short replicative life span of human peritoneal mesothelial cells

The replicative life span of cells in culture is thought to be determined by the gradually rising pool of senescent cells rather than by the simultaneous loss of proliferative capacity by all cells in the population. We found that early-passage cultures of human peritoneal mesothelial cells (HPMCs) contained a significant fraction of senescent-like cells. Furthermore, early-passage populations with a high percentage of senescent cells had a reduced subsequent life span in culture compared with populations consisting of the same number of apparently young cells but containing no senescent cells. The exposure of early-passage HPMCs to the conditioned medium from cultures containing senescent cells resulted in the retardation of growth and the induction of senescence-associated beta-galactosidase (SA-beta-Gal). This effect could be partly reduced by neutralizing TGF-beta1 activity. The timely treatment with N-tert-butyl-alpha-phenylnitrone (PBN) reduced oxidative stress, the number of early senescent cells, TGF-beta1 secretion, and ultimately extended the population life span. The effect was evident only when PBN was introduced at a very early, but not at a late, phase of tissue culture history. These results indicate that a sudden onset of senescence in early-passage HPMCs is related to oxidative stress and may influence the replicative life span of the population as a whole.

Resveratrol inhibits ovarian cancer cell adhesion to peritoneal mesothelium in vitro by modulating the production of α5β1 integrins and hyaluronic acid

OBJECTIVE Resveratrol (Res) is known to inhibit adhesion of numerous malignancies though its effect on an adherence of ovarian cancer cells to peritoneal mesothelium remains undefined. METHODS To address this issue, ovarian cancer cells (A2780, OVCAR-3, SKOV-3) were subjected to Res (10, 50, 100 μM), and then their adhesion to omentum-derived human peritoneal mesothelial cells (HPMCs) was assayed. RESULTS The study showed that Res inhibits adhesion of all ovarian cancer cell lines investigated. More importantly, this effect was evident either when cancer cells were directly treated with Res (cell-dependent activity) or when intact cancer cells were pretreated with conditioned medium (CM) generated by their counterparts subjected to Res (medium-dependent activity). Cell-dependent activity of Res has been recognized to be linked with decreased level of cellular α5β1 integrins which decreased functionality corresponds with reduced efficiency of cancer cell adhesion. Medium-related effects have been, in turn, associated with up-regulated secretion of soluble HA to environment (CM). The experiments with exogenous HA revealed the inverse relation between HA concentration in CM and cancer cell adhesion. When the CM from cells subjected with Res (with elevated HA) was supplemented with hyaluronidase, the restoration of cell adhesive capabilities occurred. CONCLUSIONS Our studies evidenced that Res affects ovarian cancer cell adhesion to HPMCs by decreasing cellular α5β1 integrin level and by increasing the secretion of HA to environment.

Resveratrol and its synthetic derivatives exert opposite effects on mesothelial cell-dependent angiogenesis via modulating secretion of VEGF and IL-8/CXCL8

We examined the effect of resveratrol (RVT) and its two derivatives (3,3′,4,4′-tetrahydroxy-trans-stilbene and 3,3′,4,4′,5,5′-hexahydroxy-trans-stilbene) on human peritoneal mesothelial cell (HPMC)-dependent angiogenesis in vitro. To this end, angiogenic activity of endothelial cells (HUVEC, HMVEC, and HMEC-1) was monitored upon their exposure to conditioned medium (CM) from young and senescent HPMCs treated with stilbenes or to stilbenes themselves. Results showed that proliferation and migration of endothelial cells were inhibited in response to indirect (HPMC-dependent) or direct RVT activity. This effect was associated with decreased secretion of VEGF and IL-8/CXCL8 by HPMCs treated with RVT, which confirmed the experiments with recombinant forms of these angiogenic agents. Angiogenic activity of endothelial cells treated with CM from HPMCs exposed to RVT analogues was more effective. Improved migration was particularly evident in cells exposed to CM from senescent HPMCs. Upon direct treatment, RVT derivatives stimulated proliferation (but not migration) of HUVECs, and failed to affect the behaviour of HMVEC and HMEC-1 cells. These compounds stimulated production of VEGF and IL-8/CXCL8 by HPMCs. Studies with neutralizing antibodies against angiogenic factors revealed that augmented angiogenic reactions of endothelial cells exposed to CM from HPMC treated with RVT analogues were related to enhanced production of VEGF and IL-8/CXCL8. Collectively, these findings indicate that RVT and its synthetic analogues divergently alter the secretion of the angiogenic factors by HPMCs, and thus modulate HPMC-dependent angiogenic responses in the opposite directions. This may have implications for the attempts of practical employment of the stilbenes for treatment of pathologies proceeding with abnormal vascularisation of the peritoneal tissue.

Mesothelial cell: a multifaceted model of aging.

Human peritoneal mesothelial cells (HPMCs) dominate within the peritoneal cavity and thus play a central role in a variety of intraperitoneal processes, including the transport of water and solutes, inflammation, host response, angiogenesis, and extracellular matrix remodeling. In addition, they contribute to the development of abdominal adhesions, peritonitis, endometriosis, cancer cell metastases, and peritoneal dialysis complications. For less than a decade the primary cultures of omental HPMCs have also been used as an experimental tool in studies on cellular aging. This paper provides the first comprehensive overview of the current state of art on molecular mechanisms underlying HPMC senescence in vitro. Special attention is paid to the causes of the very fast dynamics of HPMC senescence, and in particular to the role of non-telomeric DNA damage, the autocrine activity of TGF-β1, and the causative effects of oxidative stress. In addition, some clinical manifestations of HPMC senescence will be discussed, including its interplay with organismal aging, peritoneal dialysis, and cancer progression.

Human peritoneal fibroblasts are a potent source of neutrophil-targeting cytokines : a key role of IL-1β stimulation

Polymorphonuclear leukocyte (PMN) infiltration is a cardinal feature of peritonitis. CXC chemokine ligands 1 and 8 (CXCL1 and CXCL8), and the cytokine granulocyte colony-stimulating factor (G-CSF) are the key mediators of PMN accumulation. Increasing evidence points to an important role of human peritoneal fibroblasts (HPFB) in the response of the peritoneum to infection. We have examined the synthesis of PMN-targeting cytokines by HPFB exposed to intraperitoneal milieu as represented by peritoneal dialysate effluent (PDE) from patients undergoing peritoneal dialysis. PDE obtained during peritonitis, but not during infection-free periods, significantly increased production of CXCL1, CXCL8, and G-CSF by HPFB. The effect was largely blocked by antibodies to interleukin-1β (IL-1β), whereas neutralization of tumor necrosis factor-α (TNFα) had no major effect. Similar pattern of inhibition was observed when HPFB were exposed to conditioned media from endotoxin-stimulated peritoneal macrophages. Significance of IL-1β stimulation was further shown in experiments with recombinant cytokines. Compared with TNFα, exposure of HPFB to recombinant IL-1β resulted in a much higher release of PMN-targeting cytokines. The assessment of mRNA degradation revealed that the IL-1β-induced transcripts of CXCL1, CXCL8, and G-CSF were more stable compared with those induced by TNFα. These data indicate that HPFB can be a significant source of PMN-targeting cytokines when stimulated with IL-1β in the inflamed peritoneum.

The double-edged sword of long non-coding RNA: The role of human brain-specific BC200 RNA in translational control, neurodegenerative diseases, and cancer.

The complexity of eukaryotic organisms involves the regulation of gene expression through DNA-protein, RNA-DNA, RNA-RNA, and RNA-protein interactions. The role of RNA molecules in the regulation of genes in higher species has become even more evident with the discovery that about 97% of transcription products are represented by non-protein coding RNAs (ncRNAs) including short ncRNAs and long ncRNAs (lncRNAs). In addition to the well-characterized role of ncRNAs in different physiological cellular processes, numerous studies have also indicated the crucial roles of ncRNAs in neurological diseases and cancer. Although involvement of short ncRNA in those pathologies has already been well documented, there is only scarce evidence to show the participation of lncRNAs. One of the examples of lncRNAs is BC200 RNA, which plays an important role in the regulation of dendritic protein expression. Mislocalization and overexpression of BC200 RNA leads to inadequate RNA delivery to the synapses and results in neurodegenerative processes of Alzheimers disease and neoplastic changes in various groups of tissues. In this review, we summarize the current state of art in the field of the biological significance of lncRNAs, with particular attention paid to the physiological and pathophysiological role of BC200 RNA.

Peritoneal mesothelium promotes the progression of ovarian cancer cells in vitro and in a mice xenograft model in vivo

The role of mesothelial cells in the intraperitoneal spread of ovarian cancer is still elusive. In particular, it is unclear whether these cells constitute a passive barrier preventing cancer cell progression or perhaps act as an active promoter of this process. In this report we show that omental human peritoneal mesothelial cells (HPMCs) stimulate adhesion and proliferation of ovarian cancer cells (A2780, OVCAR-3, SKOV-3). The latter was associated with the paracrine activity of GRO-1, IL-6, and IL-8 released to the environment by HPMCs. Furthermore, the growth dynamics of ovarian cancer xenografts produced in response to i.p. injection of ovarian cancer cells together with HPMCs was remarkably greater than for implantation of cancer cells alone. A layer of peritoneal mesothelium was consistently present in close proximity to the tumor mass in every xenograft model. In conclusion, our results indicate that HPMCs play a supporting role in the intraperitoneal invasiveness of ovarian malignancy, whose effect may be attributed to their ability to stimulate adhesion and proliferation of cancer cells.

Colorectal cancer-promoting activity of the senescent peritoneal mesothelium

Gastrointestinal cancers metastasize into the peritoneal cavity in a process controlled by peritoneal mesothelial cells (HPMCs). In this paper we examined if senescent HPMCs can intensify the progression of colorectal (SW480) and pancreatic (PSN-1) cancers in vitro and in vivo. Experiments showed that senescent HPMCs stimulate proliferation, migration and invasion of SW480 cells, and migration of PSN-1 cells. When SW480 cells were injected i.p. with senescent HPMCs, the dynamics of tumor formation and vascularization were increased. When xenografts were generated using PSN-1 cells, senescent HPMCs failed to favor their growth. SW480 cells subjected to senescent HPMCs displayed up-regulated expression of transcripts for various pro-cancerogenic agents as well as increased secretion of their products. Moreover, they underwent an epithelial-mesenchymal transition in the Smad 2/3-Snail1-related pathway. The search for mediators of senescent HPMC activity showed that increased SW480 cell proliferation was stimulated by IL-6, migration by CXCL8 and CCL2, invasion by IL-6, MMP-3 and uPA, and epithelial-mesenchymal transition by TGF-β1. Secretion of these agents by senescent HPMCs was increased in an NF-κB- and p38 MAPK-dependent mechanism. Collectively, our findings indicate that in the peritoneum senescent HPMCs may create a metastatic niche in which critical aspects of cancer progression become intensified.

Bystander senescence in human peritoneal mesothelium and fibroblasts is related to thrombospondin-1-dependent activation of transforming growth factor-β1.

Senescence bystander effect refers to a phenomenon in which senescent cells elicit the development of senescence phenotype in their nearby young counterparts. In this paper we examined the mechanism of senescence bystander effect triggered by senescent human peritoneal mesothelial cells (HPMCs) in proliferating HPMCs and peritoneal fibroblasts (HPFBs). The results showed that conditioned medium (CM) derived from senescent HPMCs elicited a senescence response (growth inhibition coupled with increased expression of senescence-associated β-galactosidase and accumulation of histone γ-H2A.X) in either early-passage HPMCs or HPFBs. Samples of CM from senescent HPMCs contained increased amounts of numerous soluble mediators of which only transforming growth factor-β1 (TGF-β1) was able to induce senescence phenotype in the both types of peritoneal cells, likely through an induction of reactive oxygen species (ROS) and p38 mitogen-activated protein kinase (MAPK). At the same time, senescent HPMCs released increased amounts of thrombospondin-1 (TSP-1), a major activator of TGF-β1. Significantly, TSP-1 itself was unable to induce senescence phenotype in HPMCs or in HPFBs. The experiments employing anti-TSP-1 antibodies and specific TSP-1 blocking peptide revealed that neutralization of TSP-1 in CM prevented TGF-β1-dependent development of senescence phenotype. Collectively, our findings indicate that senescent HPMCs exhibit senescence-promoting activity toward neighboring young cells (HPMCs and HPFBs), and this effect is, at least partly, related to TSP-1-dependent activation and further ROS- and p38 MAPK-related activity of TGF-β1.