Tumor necrosis factor alpha induces invasiveness of human skin fibroblasts in vitro

Mechanisms of Fish Macrophage Antimicrobial Immunity

Overcrowding conditions and temperatures shifts regularly manifest in large-scale infections of farmed fish, resulting in economic losses for the global aquaculture industries. Increased understanding of the functional mechanisms of fish antimicrobial host defenses is an important step forward in prevention of pathogen-induced morbidity and mortality in aquaculture setting. Like other vertebrates, macrophage-lineage cells are integral to fish immune responses and for this reason, much of the recent fish immunology research has focused on fish macrophage biology. These studies have revealed notable similarities as well as striking differences in the molecular strategies by which fish and higher vertebrates control their respective macrophage polarization and functionality. In this review, we address the current understanding of the biological mechanisms of teleost macrophage functional heterogeneity and immunity, focusing on the key cytokine regulators that control fish macrophage development and their antimicrobial armamentarium.

Thrombomodulin promotes diabetic wound healing by regulating toll-like receptor 4 expression

Keratinocyte-expressed thrombomodulin (TM) and the released soluble TM (sTM) have been demonstrated to promote wound healing. However, the effects of high glucose on TM expression in keratinocytes and the role of TM in diabetic ulcer remain unclear. In this study, we demonstrated that expressions of TM and Toll-like receptor 4 (TLR4) were both downregulated in high-glucose cultured human keratinocytes and in skin keratinocytes of diabetic patients. In addition, the wound-triggered upregulation of TM and sTM production was abolished in both high-glucose cultured human keratinocytes and streptozotocin-induced diabetic mouse skin. Furthermore, supplementation of recombinant sTM could increase TLR4 expression and promote cutaneous wound healing in both high-glucose cultured human keratinocytes and diabetic mice. However, in Tlr4-deleted mice, which exhibited delayed wound healing, the therapeutic benefit of recombinant sTM was abrogated. Moreover, our results showed that tumor necrosis factor-α (TNF-α) expression in keratinocytes was dose-dependently upregulated by glucose, and TNF-α treatment downregulated the expression of TM and TLR4. Taken together, high-glucose environment reduces the expression of TM and TLR4 in keratinocytes possibly through the action of TNF-α, and recombinant sTM can increase the TLR4 expression and promote wound healing under diabetic condition.

Pre-conditioning cryosurgery: cellular and molecular mechanisms and dynamics of TNF-α enhanced cryotherapy in an in vivo prostate cancer model system

Cryosurgery is increasingly being used to treat prostate cancer; however, a major limitation is local recurrence of disease within the previously frozen tissue. We have recently demonstrated that tumor necrosis factor alpha (TNF-α), given 4h prior to cryosurgery can yield complete destruction of prostate cancer within a cryosurgical iceball. The present work continues the investigation of the cellular and molecular mechanisms and dynamics of TNF-α enhancement on cryosurgery. In vivo prostate tumor (LNCaP Pro 5) was grown in a dorsal skin fold chamber (DSFC) on a male nude mouse. Intravital imaging, thermography, and post-sacrifice histology and immunohistochemistry were used to assess iceball location and the ensuing biological effects after cryosurgery with and without TNF-α pre-treatment. Destruction was specifically measured by vascular stasis and by the size of histologic zones of injury (i.e., inflammatory infiltrate and necrosis). TNF-α induced vascular pre-conditioning events that peaked at 4h and diminished over several days. Early events (4-24 h) include upregulation of inflammatory markers (nuclear factor-κB (NFκB) and vascular cell adhesion molecule-1 (VCAM)) and caspase activity in the tumor prior to cryosurgery. TNF-α pre-conditioning resulted in recruitment of an augmented inflammatory infiltrate at day 3 post treatment vs. cryosurgery alone. Finally, pre-conditioning yielded enhanced cryosurgical destruction up to the iceball edge at days 1 and 3 vs. cryosurgery alone. Thus, TNF-α pre-conditioning enhances cryosurgical lesions by vascular mechanisms that lead to tumor cell injury via promotion of inflammation and leukocyte (esp. neutrophil) recruitment.

Cyclophilin C-associated protein is up-regulated during wound healing

Cyclophilin C-associated protein (CyCAP) is identified from macrophages. It locates in intracellular, membrane bound and extracellular, suggesting it has an important role, however both of its regulation and function have not been elucidated. The expression of CyCAP in skin and during wound healing is also unknown. We demonstrate that CyCAP is expressed in both dermal fibroblasts and keratinocytes. In the dermis, the majority of CyCAP protein is located intracellular in a filamentous protein form while a lesser amount is in the extracellular matrix (ECM). CyCAP gene and protein expression is increased 1 day after skin wound healing in both fetal and adult rats and remains elevated level up to 1 week in adult rats. Immunohistochemistry studies demonstrate that the increased CyCAP expression locates mainly to inflammatory cells, including macrophages, monocytes and lymphocytes during wound healing. Interferon-gamma increases CyCAP gene and protein expression in cultured rat fibroblasts. We also found that wound healing is slower and less collagen is expressed in skin of CyCAP null mice. These data are the first observations of CyCAP expression in skin and during wound repair. Our data indicates that CyCAP is regulated by IFNgamma and may function on immune defense in macrophages, lymphocytes, dermal fibroblasts and keratinocytes during wound healing.

Cellular, biochemical, and clinical aspects of wound healing

BACKGROUND

The response to tissue injury requires the symphonious interaction of immune cells, keratinocytes, fibroblasts, and endothelial cells, which unite to regenerate the damaged epithelium. Recent insights have elucidated the cellular and molecular mechanisms required for wound healing and have raised the prospect of novel therapeutic targets.

METHODS

Review of the pertinent literature.

RESULTS

The initial inflammatory response leads to the influx of macrophages and neutrophils, which release cytokines, growth factors, and nitric oxide, and induce nearby keratinocytes to migrate across the wounded epithelium. This process, known as re-epithelialization, requires integrin-mediated activation of Rho-GTPases. The subsequent influx of fibroblasts and endothelial cells results in the production of tissue stroma and formation of new blood vessels, which lead to the generation of functional tissue. Importantly, disease states associated with impaired or excessive wound healing can be attributed to defects in these responses, providing a rationale for the use of evidence-based biological therapies.

CONCLUSION

The elucidation of the cellular and biochemical response to wound healing is essential for an understanding to the treatment of clinical conditions during which impaired healing is encountered.

Cytokines, growth factors, and plastic surgery

Numerous inflammatory cytokines and growth factors have been identified and are known to be essential for normal wound healing and host defense, and many have been implicated in disease states treated by plastic surgeons. Cytokines and growth factors are members of a large functional group of polypeptide regulatory molecules secreted by different cell lines. These peptides exert their influence through autocrine and paracrine fashions within sites of injury and repair. Although cytokines and growth factors are crucial in initiating, sustaining, and regulating the postinjury response, these same molecules have been implicated in impaired wound healing, abnormal scarring, and chronic cutaneous diseases. Therapeutic manipulation of inflammatory mediators in normal and impaired wounds has been performed, with mixed clinical results, but evolving strategies such as gene therapy, as well as further characterization of the cellular-mechanism cytokines and growth-factor triggers, will further add to our therapeutic options. This article discusses the current understanding of important cytokines and growth factors involved in the normal injury response and then addresses pathological states associated with an inappropriate expression of these mediators. Finally, a summary of various cytokine and growth factor-directed strategies being used in impaired wound healing states is presented.

Effectors of inflammation in actinic prurigo

BACKGROUND

Actinic prurigo is a specific familial photodermatosis of uncertain pathogenesis.

OBJECTIVE

Our purpose was to investigate the immunohistologic presentation of actinic prurigo to explore the involved pathomechanisms.

METHODS

The present immunohistochemical study was performed on biopsy specimens from 20 Mexican patients presenting with a severe and perennial form of the disease.

RESULTS

The dense inflammatory infiltrate was composed predominantly of helper T type 1 lymphocytes admixed with scattered B-cell lymphoid follicles and numerous dermal dendrocytes. Keratinocytes contained abundant tumor necrosis factor-alpha and calprotectin.

CONCLUSION

In subjects genetically predisposed to actinic prurigo, ultraviolet light may trigger excessive tumor necrosis factor-alpha production by keratinocytes whose sustained release in turn exerts its proinflammatory activity and deleterious epidermal effects. Such a cascade of events is in line with the therapeutic benefit already reported when thalidomide is used to treat actinic prurigo.

Mast cells as modulators of hair follicle cycling

While the central role of mast cells (MC) in allergy and inflammation is well-appreciated, much less is known about their physiological functions. The impressive battery of potent growth modulatory MC products, and increasing evidence of MC involvement in hyperproliferative and fibrotic disorders suggest that tissue remodelling may be one of those, namely in the skin. Here, we delineate why this may best be studied by analysing the potential role of MC in hair growth regulation. On the background of numerous, yet widely under-appreciated hints from the older literature, we summarize and discuss our recent observations from the C57BL/6 mouse model for hair research which support the concept that MC are functionally important modulators of hair follicle cycling, specifically during anagen development. This invites to exploit the murine hair cycle as a model for dissecting the physiological growth modulatory functions of MC and encourages the exploration of MC-targeting pharmaceutical strategies for the treatment of hair growth disorders.

Neutrophils express tumor necrosis factor-alpha during mouse skin wound healing

The expression pattern of tumor necrosis factor-alpha (TNF-alpha) mRNA and protein was examined in vivo in experimental mouse skin wounds by in situ hybridization and immunohistochemistry. TNF-alpha mRNA and protein is detected in a distinct layer of mainly neutrophils subadjacent to the would clot. The layer of TNF-alpha-positive cells extends from the margin of the advancing epithelial outgrowth to the opposing one. By in situ hybridization the TNF-alpha mRNA is detectable 12 h after wounding; the signal peaks after 72 h and remains visible up to at least 120 h after wounding. TNF-alpha mRNA could not be detected in the normal skin or in 5-hour-old wounds. Immunohistochemical staining for TNF-alpha and macrophages on adjacent sections confirms that the main part of TNF-alpha-positive cells are polymorphonuclear neutrophils and shows that most of the cells located just beneath the layer of TNF-alpha-positive neutrophils are macrophages with weak TNF-alpha immunoreactivity. The data reported here show that neutrophils serve as an important source of TNF-alpha during healing of mouse skin wounds. We suggest that this specific expression of TNF-alpha is related to the process of re-epithelialization.

Extracorporeal photochemotherapy induces the production of tumor necrosis factor-alpha by monocytes: implications for the treatment of cutaneous T-cell lymphoma and systemic sclerosis

Extracorporeal photopheresis (ExP) has been shown to be an efficacious and well-tolerated therapy in the treatment of cutaneous T-cell lymphoma (CTCL) and systemic sclerosis. However, the precise mechanisms of its action have not been defined. Because of a correlation between the development of fever in the early phase of treatment of CTCL and subsequent anti-tumor responses, we examined the production of the proinflammatory, pyrogenic cytokines tumor necrosis factor-alpha (TNF), IL-6, IL-1 alpha, and IL-1 beta before and after ExP. Monocytes were purified from peripheral blood specimens of normal volunteers (n = 4) or from peripheral blood specimens of CTCL (n = 6) or systemic sclerosis (n = 3) patients that were obtained immediately prior to ExP and also directly from the photopheresis unit after ExP, just prior to reinfusion into the patient. Monocytes were then cultured under various conditions for 16 h, after which the culture supernatants were collected and assayed for specific cytokine production. ExP induced a significant increase in the production of TNF (p less than 0.008) and IL-6 (p less than 0.05) as compared to non-ExP-treated cells, whereas no significant differences were observed in IL-1 alpha (p less than 0.5) and IL-1 beta (p less than 0.2) production following ExP. Exposure of monocyte cultures to IFN-gamma (100 U/mL) either before or after ExP further enhanced TNF production by 4 to 28 times. In contrast, incubation with IFN-alpha (100 U/mL) had no significant effect on TNF production. Addition of TNF (500 U/ml) to monocyte cultures obtained prior to ExP resulted in a slight but insignificant increase in TNF production in 2 of 10 cases. However, when monocytes obtained prior to ExP were incubated with 8-methoxypsoralen (8-MOP, 100 ng/ml), exposed to ultraviolet light A (UVA, 2J/cm2), washed, and then incubated with TNF, a significant increase (p less than 0.01) in TNF production was observed in 8 of 10 cases, suggesting that the combination of 8-MOP and UVA may sensitize cells to TNF. Based on studies of endotoxin (LPS)-stimulated production of TNF by monocytes, levels of endotoxin in culture reagents or photopheresis equipment could not account for the increased production of TNF following treatment by ExP. Increased TNF production as a result of ExP may have important implications for treating both CTCL and systemic sclerosis because, in the case of CTCL, it could mediate numerous anti-tumor effects, whereas, in the case of systemic sclerosis, it could suppress collagen synthesis and induce collagenase production.

The effect of interferon-gamma on the invasiveness of HT-180 cells

It has been shown that tumour necrosis factor-alpha (TNF-alpha) induces the gene expression of collagenase and enhances the invasiveness of many cell types. However, we have previously demonstrated that interferon-gamma (IFN-gamma) induces the chemotactic response of cells and we have studied the in vitro effects of both cytokines on invasive migration using a human fibrosarcoma cell line (HT-1080). Invasive migration occurred with HT-1800 cells through a basement membrane equivalent (matrigel) and collagen type I gel. Pre-incubation of cells with increasing concentrations of IFN-gamma resulted in a dose-dependent reduction of this invasive migration. TNF-alpha considerably enhanced the invasiveness of HT-1080 cells and of fibroblasts. This effect could be significantly diminished by the pre-incubation of cells with IFN-gamma. Inhibition of invasiveness did not appear to be due to an altered binding to the barriers or altered collagenolytic activity of these cells, as shown by attachment and collagenase assays. These data support the concept that IFN-gamma can reduce the invasiveness of transformed cells which contributes to its in vivo anti-neoplastic effect.

Cytokines, fibrosis and the failure of glaucoma filtration surgery

Current therapies for the prevention of fibrosis after glaucoma filtering surgery can be effective but often produce unwanted side effects. An understanding of the cellular basis of the fibrotic reaction may lead to better treatments. Wound repair revolves around angiogenesis and the activation of fibroblasts by cytokines. These peptides, a number of which have been described, act together in intricately complicated networks to encourage fibroblast chemotaxis, proliferation and contractility, as well as to stimulate the production of glycosaminoglycans and collagen. Since interferons seem to inhibit many of these responses, they deserve further evaluation in the treatment of ocular fibrosis.

Detection of undegraded fibrin and tumor necrosis factor-alpha in venous leg ulcers

The pathogenesis of venous leg ulcers is based on the leakage of fibrinogen leading to pericapillary fibrin cuff and plugging of capillaries by white blood cells. Eight patients with venous leg ulcers have been studied with a panel of antibodies reactive for fibrinogen, fibrin, fibrin degradation products, and various cell-associated markers for polymorphonuclear cells, monocytes, and B and T lymphocytes. Our results showed that pericapillary fibrin cuff was mainly composed of undegraded fibrin and that, in the granulation tissue, tumor necrosis factor-alpha and elastase activities were detectable in monocytes and polymorphonuclear cells, respectively. Only few activated lymphocytes were present. On the basis of these results, it is assumed that inflammation generated by activated white blood cells that accumulate under unrelieved pressure is the key event. Tumor necrosis factor-alpha synthesized by activated monocytes may therefore induce the formation of pericapillary fibrin cuffs. Pericapillary fibrin cuffs and toxic metabolites released by polymorphonuclear cells may explain the absence of wound repair.

Tumor necrosis factor

Tumor necrosis factor is important in systemic and cutaneous defense, homeostasis, and many disease states. The numerous and diverse effects of tumor necrosis factor are best understood when considered as concentration-dependent, with normal homeostasis progressing to defense followed by toxic effects. Understanding tumor necrosis factor is important for the dermatologist as more studies appear in our literature and potential clinical uses of tumor necrosis factor (and possible anti-tumor necrosis factor agents) are realized.

Invasive migration of epidemic Kaposi's sarcoma cells in vitro

Kaposi's sarcoma (KS) is a low grade malignant neoplasm which shows invasive growth and often occurs in immunosuppressed patients with the Acquired Immune Deficiency Syndrome (AIDS; epidemic KS). It is also found in elderly men where it is usually limited to the skin (classic KS). The present study investigated the chemotaxis and invasive migration of epidemic KS cells in vitro and compared them to cells grown from classic KS lesions and to fibroblasts. Epidemic KS cells demonstrated invasive migration through reconstituted basement membrane (Matrigel) as well as through interstitial connective tissue (collagen I) in early passages, whereas fibroblasts did not invade either barrier. Epidemic KS cells in late passages did not show any invasive migration. Following pretreatment with tumour necrosis factor alpha (TNF-alpha) there was no enhanced migration through the Matrigel and collagen I for epidemic KS cells, whereas classic KS cells showed an increased migration through the type I collagen barrier.