Effects of rIFN alpha, beta, and gamma on the morphology, proliferation, and cell surface antigen expression of human dermal microvascular endothelial cells in vitro

Small-molecule antagonist of VLA-4 (GW559090) attenuated neuro-inflammation by targeting Th17 cell trafficking across the blood-retinal barrier in experimental autoimmune uveitis

Background

The integrin VLA-4 (α4β1) plays an important role in leukocyte trafficking. This study investigated the efficacy of a novel topical α4β1 integrin inhibitor (GW559090, GW) in a mouse model for non-infectious posterior uveitis (experimental autoimmune uveitis; EAU) and its effect on intraocular leukocyte subsets.

Methods

Mice (female; B10.RIII or C57Bl/6; aged 6–8 weeks) were immunized with specific interphotoreceptor retinoid-binding protein (IRBP) peptides to induce EAU. Topically administered GW (3, 10, and 30 mg/ml) were given twice daily either therapeutically once disease was evident, or prophylactically, and compared with vehicle-treated (Veh) and 0.1% dexamethasone-treated (Dex) controls. Mice were sacrificed at peak disease. The retinal T cell subsets were investigated by immunohistochemistry and immunofluorescence staining. The immune cells within the retina, blood, and draining lymph nodes (dLNs) were phenotyped by flow cytometry. The effect of GW559090 on non-adherent, adherent, and migrated CD4⁺ T cell subsets across a central nervous system (CNS) endothelium was further assayed in vitro and quantitated by flow cytometry.

Results

There was a significant reduction in clinical and histological scores in GW₁₀- and Dex-treated groups as compared to controls either administered therapeutically or prophylactically. There were fewer CD45⁺ leukocytes infiltrating the retinae and vitreous fluids in the treated GW₁₀ group (P < 0.05). Immunofluorescence staining and flow cytometry data identified decreased levels of retinal Th17 cells (P ≤ 0.001) in the GW₁₀-treated eyes, leaving systemic T cell subsets unaffected. In addition, fewer Ly6C⁺ inflammatory monocyte/macrophages (P = 0.002) and dendritic cells (P = 0.017) crossed the BRB following GW₁₀ treatment. In vitro migration assays confirmed that Th17 cells were selectively suppressed by GW559090 in adhering to endothelial monolayers.

Conclusions

This α4β1 integrin inhibitor may exert a modulatory effect in EAU progression by selectively blocking Th17 cell migration across the blood-retinal barrier without affecting systemic CD4⁺ T cell subsets. Local α4β1 integrin-directed inhibition could be clinically relevant in treating a Th17-dominant form of uveitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02080-8.

Functionally distinct IFN-γ+ IL-17A+ Th cells in experimental autoimmune uveitis: T-cell heterogeneity, migration, and steroid response

Immunopathogenic roles for both Th1 (CD4⁺ IFN-γ⁺ ) and Th17 (CD4⁺ IL-17A⁺ ) cells have been demonstrated in experimental autoimmune uveitis (EAU). However, the role for Th17/Th1 (CD4⁺ T cells co-expressing IFN-γ and IL-17A) cells in EAU is not yet understood. Using interphotoreceptor retinoid-binding protein peptide-induced EAU in mice, we found increased levels of Th17/Th1 cells in EAU retinae (mean 9.6 ± 4.2%) and draining LNs (mean 8.4 ± 3.9%; p = 0.01) relative to controls. Topical dexamethasone treatment effectively reduced EAU severity and decreased retinal Th1 cells (p = 0.01), but had no impact on retinal Th17/Th1 or Th17 cells compared to saline controls. Using in vitro migration assays with mouse CNS endothelium, we demonstrated that Th17/Th1 cells were significantly increased within the migrated population relative to controls (mean 15.6 ± 9.5% vs. 1.9 ± 1.5%; p = 0.01). Chemokine receptor profiles of Th17/Th1 cells (CXCR3 and CCR6) did not change throughout the transendothelial migration process and were unaffected by dexamethasone treatment. These findings support a role for Th17/Th1 cells in EAU and their resistance to steroid inhibition suggests the importance of targeting both Th17 and Th17/Th1 cells for improving therapy.

Endothelial cell functions impaired by interferon in vitro: Insights into the molecular mechanism of thrombotic microangiopathy associated with interferon therapy

INTRODUCTION

Interferon (IFN)-α and IFN-β approved for treatment of chronic hepatitis C viral infection and multiple sclerosis respectively have been linked to thrombotic microangiopathy (TMA) affecting renal function. Since the molecular mechanisms underlying this severe complication remain largely unclear, we aimed to investigate whether IFN affects directly in vitro endothelial cell functions associated with angiogenesis and blood haemostasis, as well as endothelial cell-derived vasodilators of nitric oxide (NO) and prostacyclin.

METHODS

Proliferation and survival of human umbilical vein endothelial cells (HUVECs) were measured by BrdU incorporation and alamarBlue assays. Angiogenesis was evaluated in co-cultures of HUVECs and human dermal fibroblasts. Fibrinolysis molecules were measured with ELISA. NO and prostacyclin were measured using a fluorescent NO-specific probe and a competitive enzyme immunoassay, respectively.

RESULTS

HUVEC proliferation was dose-dependently inhibited by IFN-β1a and IFN-β1b, but not by IFN-α2a and IFN-α2b. Consistently, IFN-β1a and IFN-β1b also reduced survival of HUVECs, but this again was not observed with IFN-α. However, both IFN subtypes inhibited VEGF-induced development of capillary-like structures, but the effect of IFN-α was less potent than IFN-β. In addition, both IFN subtypes upregulated interferon inducible protein 10 production from treated co-cultures while suppressing angiogenesis. Furthermore, intracellular NO generation was reduced by IFN-α2a and IFN-β1a, whereas prostacyclin release from HUVECs was not affected by IFN. Importantly, both IFN-β1a- and IFN-β1b-treated HUVECs showed a marked reduction in urokinase-type plasminogen activator release and a much greater secretion of plasminogen activator inhibitor-1 than tissue-type plasminogen activator compared with untreated cells, suggesting decreased fibrinolytic activity. IFN-α, however was less effective in modulating the fibrinolysis system.

CONCLUSIONS

We demonstrate the detrimental effects of IFN on endothelial cell functions mediated with angiogenesis and fibrinolysis, which could potentially cause the loss of physiological endothelium thromboresistance and facilitate the development of vascular complications in a clinical setting. Mechanistically, our findings have implications for understanding how IFN therapy can foster the development of TMA.

The effect of type 1 IFN on human aortic endothelial cell function in vitro: relevance to systemic lupus erythematosus

Cardiovascular disease (CVD) is an important cause of morbidity and mortality in patients with systemic lupus erythematosus. The etiopathogenesis of premature CVD is not fully understood, but recently interferon-alpha (IFNα) has been implicated as a contributing factor. Since IFNα has been associated with both disease activity and endothelial dysfunction in lupus patients, we aimed to determine whether IFNα has direct effects on human aortic endothelial cell (HAoEC) function in vitro. We studied the function of IFNα2b-treated HAoECs in terms of cell proliferation, capillary-like network formation, and nitric oxide (NO) generation. Changes in gene expression were also analyzed using an exon gene array. IFNα2b regulated the expression of 198 genes, including recognized interferon-stimulated genes (ISGs). Gene ontology analysis showed over-representation of genes involved in antigen presentation and host response to virus but no significant changes in clusters of genes recognized as important in endothelial cell activation or dysfunction. HAoEC proliferation, tubule formation, and NO bioavailability were unchanged, suggesting that IFNα in isolation does not have a direct impact on aortic endothelial cell function.

Expression of interferon-γ, interferon-α and related genes in individuals with Down syndrome and periodontitis

BACKGROUND

Recently, attenuation of anti-inflammatory and increase of pro-inflammatory mediators was demonstrated in individuals with Down syndrome (DS) in comparison with euploid patients during periodontal disease (PD), suggesting a shift to a more aggressive inflammation in DS.

AIM

To determine the influence of DS in the modulation of interferons (IFNs) signaling pathway in PD.

MATERIALS AND METHODS

Clinical periodontal assessment was performed and gingival tissue samples obtained from a total of 51 subjects, including 19 DS individuals with PD, 20 euploid individuals with PD and 12 euploid individuals without PD. Expression levels of interferon-gamma (IFNG) and interferon-alpha (IFNA), and their receptors IFNGR1, IFNGR2, IFNAR1 and IFNAR2, the signaling intermediates Janus kinase 1 (JAK1), signal transducer and activator of transcription 1 (STAT1) and interferon regulatory factor 1 (IRF1) were determined using real time quantitative polymerase chain reaction (qPCR).

RESULTS

Clinical signs of periodontal disease were markedly more severe in DS and euploid patients with PD in comparison to euploid and periodontally healthy patients. There was no difference on mRNA levels of IFNA, IFNG, INFGR2, IFNAR1 and IFNAR2 between DS and euploid individuals, even though some of these genes are located on chromosome 21. STAT1 and IRF1 mRNA levels were significantly lower in DS patients in comparison with euploid individuals with PD. In euploid individuals, PD was associated with an increased expression of IFNGR1, IFNGR2, IFNAR1, STAT1 and IRF1.

CONCLUSIONS

Reduced expression of STAT1 and IRF1 genes indicate an impaired activation of IFNs signaling in individuals with DS and PD. Expression of IFNA, IFNG and IFN receptors was not altered in DS patients, indicating that indirect mechanisms are involved in the reduced activation of IFN signaling.

Influences of interferon-gamma on cell proliferation and interleukin-6 production in Down syndrome derived fibroblasts

OBJECTIVE

Down syndrome, a frequently encountered genetic disorder, is usually associated with medical problems related to infectious disease, such as periodontal diseases and prolonged wound healing. Although affected individuals are considered to have clinical problems related to high interferon (IFN) sensitivity, the molecular mechanisms of IFN activities are not completely understood.

DESIGN

Down syndrome derived fibroblasts, Detroit 539 (D1) and Hs 52.Sk (D2) cells, were used. To analyse the expressions of interferon (IFN) receptors and downstream of IFN-gamma, western blotting was performed. Cell proliferation was determined by counting cells following trypan blue staining. Media levels of IL-1beta, TNF-alpha, and IL-6 were quantified using ELISA.

RESULTS

IFN-gamma receptor 2 and IFN-alpha receptor 1, but not IFN-gamma receptor 1, were highly expressed in D1 and D2 cells, as compared to the control fibroblast cells. Cell proliferation by D1 and D2 cells was lower than that by the control fibroblasts, further, IFN-gamma had a greater effect to inhibit cell proliferation by D1 and D2 cells. In addition, IFN-gamma treatment increased the phosphorylation of STAT1 and MAPK in D1 cells as compared to normal fibroblasts. Also, the presence of exogenous IFN-gamma in the growth medium significantly induced IL-6, but not IL-1beta or TNF-alpha, in D1 and D2 cells.

CONCLUSION

Taken together, our results are consistent with hypersensitive reactions to IFN-gamma seen in patients with Down syndrome and may provide useful information to elucidate the mechanisms of IFN-gamma activities in those individuals.

An assay for macrophage-mediated regulation of endothelial cell proliferation

We have developed an assay that quantifies the potential of macrophages to regulate proliferation of endothelial cells. We show that young mice macrophages can be distinguished from old mice macrophages by their ability to inhibit vascular endothelial cell proliferation. While young mice macrophages robustly inhibit proliferation, old mice macrophages fail to do so and actually promote the proliferation of endothelial cells. In this report, we outline a technique that directly assesses the effect of macrophages on modulation of endothelial cell proliferation. This assay will help us in understanding the mechanisms of macrophage function in several disease states characterized by abnormal angiogenesis including cancers, angiogenic eye disease and atherosclerotic heart disease.

IFN-alpha induces transcription of hypoxia-inducible factor-1alpha to inhibit proliferation of human endothelial cells

Expression of hypoxia-inducible factor (HIF)-1alpha, a transcription factor subunit increased by protein stabilization in response to hypoxia, is increased in human endothelial cells (ECs) by IFN-alpha under normoxic conditions. IFN-alpha increases HIF-1alpha transcript levels within 2 h by up to 50% and doubles HIF-1alpha protein expression. Based on pharmacological inhibition studies, the increase in HIF-1alpha mRNA involves new transcription, is independent of new protein synthesis, and requires JAK signaling. Protein knockdown by small interfering RNA confirms the involvement of JAK1 and TYK2, as well of IFN-stimulated gene factor 3 (ISGF3). IFN-gamma does not significantly induce HIF-1alpha mRNA, but increases the magnitude and duration of the IFN-alpha effect. IFN-alpha-induced HIF-1alpha protein translocates to the nucleus and can bind to hypoxia response elements in DNA. However, IFN-alpha treatment fails to induce transcription of several prototypic HIF-responsive genes (VEGF-A, PPARgamma, and prostacyclin synthase) due to an insufficient increase in HIF-1alpha protein levels. Although certain other HIF-responsive genes (PHD3 and VEGF-C) are induced following IFN-alpha and/or IFN-gamma treatment, these responses are not inhibited by siRNA knockdown of HIF-1alpha. Additionally, IFN-alpha induction of ISGF3-dependent genes involved in innate immunity (viperin, OAS2, and CXCL10) are also unaffected by knockdown of HIF-1alpha. Interestingly, knockdown of HIF-1alpha significantly reduces the capacity of IFN-alpha to inhibit endothelial cell proliferation. We conclude that IFN-alpha induces the transcription of HIF-1alpha in human endothelial cells though a JAK-ISGF3 pathway under normoxic conditions, and that this response contributes to the antiproliferative activity of this cytokine.

Heat stroke and cytokines

Heat stroke is a life-threatening illness that affects all segments of society, including the young, aged, sick, and healthy. The recent high death toll in France (Dorozynski, 2003) and the death of high-profile athletes has increased public awareness of the adverse effects of heat injury. However, the etiology of the long-term consequences of this syndrome remains poorly understood such that preventive/treatment strategies are needed to mitigate its debilitating effects. Cytokines are important modulators of the acute phase response (APR) to stress, infection, and inflammation. Current data implicating cytokines in heat stroke responses are mainly from correlation studies showing elevated plasma levels in heat stroke patients and experimental animal models. Correlation data fall far short of revealing the mechanisms of cytokine actions such that additional research to determine the role of these endogenous substances in the heat stroke syndrome is required. Furthermore, cytokine determinations have occurred mainly at end-stage heat stroke, such that the role of these substances in progression and long-term recovery is poorly understood. Despite several studies implicating cytokines in heat stroke pathophysiology, few studies have examined the protective effect(s) of cytokine antagonism on the morbidity and mortality of heat stroke. This is particularly surprising since heat stroke responses resemble those observed in the endotoxemic syndrome, for which a role for endogenous cytokines has been strongly implicated. The implication of cytokines as mediators of endotoxemia and the presence of circulating endotoxin in heat stroke patients suggests that much knowledge can be gained from applying our current understanding of endotoxemic pathophysiology to the study of heat stroke. Heat shock proteins (HSPs) are highly conserved proteins that function as molecular chaperones for denatured proteins and reciprocally modulate cytokine production in response to stressful stimuli. HSPs have been shown repeatedly to confer protection in heat stroke and injury models. Interactions between HSPs and cytokines have received considerable attention in the literature within the last decade such that a complex pathway of interactions between cytokines, HSPs, and endotoxin is thought to be occurring in vivo in the orchestration of the APR to heat injury. These data suggest that much of the pathophysiologic changes observed with heat stroke are not a consequence of heat exposure, per se, but are representative of interactions among these three (and presumably additional) components of the innate immune response. This chapter will provide an overview of current knowledge regarding cytokine, HSP, and endotoxin interactions in heat stroke pathophysiology. Insight is provided into the potential therapeutic benefit of cytokine neutralization for mitigation of heat stroke morbidity and mortality based on our current understanding of their role in this syndrome.

Immunopathogenesis of psoriasis

Psoriasis is a chronic skin disease that affects about 1.5% of the Caucasian population and is characterized by typical macroscopic and microscopic skin alterations. Psoriatic lesions are sharply demarcated, red and slightly raised lesions with silver-whitish scales. The microscopic alterations of psoriatic plaques include an infiltration of immune cells in the dermis and epidermis, a dilatation and an increase in the number of blood vessels in the upper dermis, and a massively thickened epidermis with atypical keratinocyte differentiation. It is considered a fact that the immune system plays an important role in the pathogenesis of psoriasis. Since the early 1990s, it has been assumed that T1 cells play the dominant role in the initiation and maintenance of psoriasis. However, the profound success of anti-tumor necrosis factor-alpha therapy, when compared with T-cell depletion therapies, should provoke us to critically re-evaluate the current hypothesis for psoriasis pathogenesis. Recently made discoveries regarding other T-cell populations such as Th17 and regulatory T cells, dendritic cells, macrophages, the keratinocyte signal transduction and novel cytokines including interleukin (IL)-22, IL-23 and IL-20, let us postulate that the pathogenesis of psoriasis consists of distinct subsequent stages, in each of them different cell types playing a dominant role. Our model helps to explain the varied effectiveness of the currently tested immune modulating therapies and may enable the prediction of the success of future therapies.

The evaluation of psoriasis therapy with biologics leads to a revision of the current view of the pathogenesis of this disorder

Psoriasis is a common chronic, recurring skin disease that is characterised by typical macroscopic and microscopic skin alterations. It is widely accepted that the immune system plays an important role in the pathogenesis of this disorder. Since the early 1990s, the dominant role of a subpopulation of T cells, so-called T1 cells, and their prominent cytokine IFN-gamma has been assumed in the pathogenesis of psoriasis. Surprisingly, the comparison of the therapeutic success of treatments with recombinant proteins directed against defined immunological structures shows that those that directly affect T cells (alefacept, efalizumab, Hu-max-CD4, OKTcdr4a) were clearly less effective than those targeting TNF-alpha (etanercept, adalimumab, infliximab). For this reason, the authors critically re-evaluated the view of psoriasis pathogenesis and postulate that in the majority of patients the T1 cells do not play a dominant role in the clinical, visible stage of this disease.

Interferon-alpha prevents apoptosis of endothelial cells after short-term exposure but induces replicative senescence after continuous stimulation

Although the antiangiogenic activity of type I interferons (IFN) is well known, the mechanism by which it occurs is unclear. In the present study, we have investigated effects of short-term and long-term IFN-alpha exposure on different types of endothelial cells (EC). Short-term IFN-alpha treatment resulted in a distinct reduction of apoptosis of serum and growth factor starved HUVEC and HDMEC. This was accompanied by a strong upregulation of the IFN inducible guanylate binding protein-1 (GBP-1) whereas no consistent regulation of several known antiapoptotic proteins was evident. Stable transfection of HUVEC with an expression vector for GBP-1 mimicked the protective effect of IFN-alpha, suggesting that GBP-1 may contribute to the inhibition of apoptosis. When IFN-alpha, together with serum and EC growth factors, was present continuously a decrease of population doublings by more than 40% was observed in both HDMEC and HCAEC. In addition, the cells displayed a senescent phenotype significantly earlier than control cells and showed an increased adherence for monocytes. Our findings suggest that the antiangiogenic effect of IFN-alpha is mediated by inducing EC senescence rather than EC apoptosis. Furthermore IFN-alpha released in chronic inflammatory conditions might contribute via its prosenescent activity to the pathogenesis of atherosclerosis.

Regulation of neoplastic angiogenesis

The progressive growth of neoplasms and the production of metastasis depend on the development of adequate vasculature, i.e., angiogenesis. The extent of angiogenesis is determined by the balance between positive- and negative-regulating molecules that are released by tumor and host cells in the microenvironment. The growth of many neoplasms is associated with the absence of the endogenous inhibitor of angiogenesis, interferon beta (IFN beta). A survey of multiple mouse and human tumors shows a lack of IFN beta associated with extensive angiogenesis. Therapy with IFN alpha or beta either by subcutaneous injection of the protein or by introduction of viral vectors that contain the IFN beta gene inhibit angiogenesis and, hence, progressive tumor growth.

Antiproliferative effects of IFN-alpha correlate with the downregulation of nuclear factor-kappa B in human Burkitt lymphoma Daudi cells

Interferon-alpha (IFN-alpha) is known to exhibit antiviral, antiproliferative, and immunomodulatory properties through mechanisms still not fully understood. Nuclear transcription factor-kappaB (NF-kappaB) plays a major role in viral replication, cell proliferation, and immune response. Whether antiproliferative effects of IFN are mediated through suppression of NF-kappaB is not known. We, therefore, examined the relationship between the antiproliferative effects of IFN-alpha and NF-kappaB activity in a human Burkitt lymphoma Daudi cell line. These cells were found to constitutively express high levels of active NF-kappaB that cannot be further activated by tumor necrosis factor (TNF). Treatment of cells with IFN-alpha suppressed the activated NF-kappaB in a dose-dependent manner, with an optimum effect at 10 U/ml in 72 h. Suppression of NF-kappaB correlated with a concomitant decrease in the cytoplasmic levels of IkappaBalpha, the inhibitory protein of NF-kappaB, known to be regulated by NF-kappaB. Downregulation of constitutive NF-kappaB activity correlated with a decrease in cell proliferation by IFN-alpha. Overall, our results suggest that IFN-alpha is a potent suppressor of constitutive NF-kappaB, which may contribute to the inhibition of cell proliferation.

Interferon-gamma and interleukin-10 reciprocally regulate endothelial junction integrity and barrier function

Inflammatory bowel disease (IBD) is associated with Th1/Th2 cytokine dysregulation, leukocyte extravasation, and tissue edema, but the mechanisms for cytokine-mediated vascular dysfunction are not understood. To investigate how cytokines might control edema in IBD, we determined vascular permeability and IFN-gamma expression in two models of murine colitis: SCID mice reconstituted with CD45RB(high T-lymphocytes (CD45RB(high)/SCID mice), and interleukin-10 gene deficient (IL-10(-/-)) mice. We also investigated the in vitro effects of IFN-gamma and IL-10 on human endothelial solute barrier and junction protein expression. Vascular permeability in CD45RB(high)/SCID and IL-10(-/-) mice was quantified using tissue (131)I-IgG accumulation. The IFN-gamma message was quantified using the ribonuclease protection assay. Endothelial barrier integrity in vitro was measured by transmonolayer electrical resistance, and junctional proteins were examined by immunoblotting and fluorescence microscopy. Both CD45RB(high)/SCID and IL-10(-/-) mice exhibit enhanced colonic microvascular leakage and IFN-gamma message levels compared to their respective controls. In vitro, IFN-gamma also reduced endothelial barrier (monolayer electrical resistance, increased albumin permeability) and reduced tight junction (occludin) expression and staining. These effects were reversed by pretreatment of monolayers with IL-10. Therefore, in vivo IFN-gamma and IL-10 may modulate microvascular leakage in IBD partly by controlling the expression of intestinal endothelial tight junctional proteins.

New therapeutic strategies for the treatment and prevention of head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy that is now the sixth most common neoplasm in the world today. Approximately 50,000 cases in the United States and more than 500,000 cases worldwide will be diagnosed in 2000 [1]. Despite numerous advances in treatment utilising the most recent protocols for surgery, radiation and chemotherapy, the long-term survival has remained at less than 50% over the past 40 years [2]. This poor long-term survival is due to a number of variables including delayed diagnosis as well as the frequent development of multiple primary tumours. Therefore, in addition to early detection, continued emphasis must be placed on preventing the development of new primaries as well as establishing more effective treatments for individuals who present with advanced disease. This review will summarise some of the recent advances in the realms of chemotherapy and radiation therapy. In addition, it will discuss the present status of chemoprevention in HNSCC. Finally, we will discuss the rationale for the use of anti-angiogenic agents as one possible means of developing new chemopreventive protocols that result in reduced toxicity while maintaining similar clinical efficacies.

High-dose and long-term therapy with interferon-alfa inhibits tumor growth and recurrence in nude mice bearing human hepatocellular carcinoma xenografts with high metastatic potential

Postoperative recurrence of human hepatocellular carcinoma (HCC) is the major issue that must be addressed to further improve prognosis. This study was undertaken to investigate the effects of interferon-alfa-1b (IFN-alpha-1b) on recurrent tumor and metastasis after curative resection in nude mice bearing an HCC xenograft with high metastatic potential. Tumor tissues from LCI-D20, a metastatic model of HCC in nude mice, were orthotopically implanted in 105 nude mice. Eleven days later, 64 mice underwent curative resection of liver tumors. IFN-alpha at different doses was administered subcutaneously to mice with or without resection. In mice without resection, when comparison was made among control, IFN 7.5 x 10(6) U/kg/day, 1.5 x 10(7) U/kg/day for treated groups, and 3 x 10(7) U/kg/day; tumor volume was 8,475 mm(3) +/- 2,636 mm(3), 7,963 mm(3) +/- 3,214 mm(3), 769 mm(3) +/- 287 mm(3), and 13 mm(3) +/- 9 mm(3); incidence of lung metastasis being 100%, 80%, 40%, and 0%; life span was 45 +/- 4 days, 53 +/- 8 days, 81 +/- 6 days, and 105 +/- 24 days, respectively. In mice with curative resection, when comparison was made among control, IFN 5 x 10(5) U/kg/day, 1 x 10(6) U/kg/day, 4 x 10(6) U/kg/day, 7.5 x 10(6) U/kg/day, 1.5 x 10(7) U/kg/day, and 3 x 10(7) U/kg/day for treated groups; incidence of recurrent tumor was 100%, 100%, 87.5%, 100%, 87.5%, 62.5%, and 12.5%; lung metastasis being 100%, 75%, 87.5%, 50%, 62.5%, 0%, and 0%, respectively. IFN-alpha inhibited neovascularization induced by LCI-D20 tumor specimens implanted into the micropocket of nude mice corneas. In conclusion, high-dose and long-term therapy with IFN-alpha dose-dependently inhibits tumor growth and recurrence after resection of HCC. The effect of IFN-alpha may be attributed to antiangiogenesis in this experiment. These results provide potential clinical implication, particularly for the prevention of recurrence after curative resection of HCC.

Angiogenesis in the development of head and neck cancer and its inhibition by chemopreventive agents

Squamous cell carcinoma is an aggressive malignancy that often develops as multiple independent lesions throughout the mucosa of the upper aerodigestive tract. Therefore, the comprehensive treatment of this disease must not only address the initial primary neoplasm, but also prevent the progression of the premalignant lesions lurking throughout the rest of the mucosal surfaces. The need to treat these lesions has resulted in a search for chemopreventive agents that can halt or even reverse their malignant progression. The biologic and molecular mechanisms by which most chemopreventive agents act have remained unclear and controversial. Recent work from several laboratories has demonstrated that some drugs may act in part by inhibiting the ability of tumors to induce blood vessel growth. Angiogenesis, the growth of new blood vessels from pre-existing ones, is absolutely required for solid neoplasms to grow beyond 2-3 mm in diameter. Therefore, chemopreventive agents that act to inhibit angiogenesis may provide a very powerful modality by which one may limit the growth of both pre-malignant lesions and small nests of tumor cells. This review will outline the basic changes that occur in tumor cells that result in the switch from an anti-angiogenic to an angiogenic phenotype. In addition, it will discuss the mechanisms by which some chemopreventive agents, presently under clinical investigation, inhibit tumor angiogenesis. Finally, this paper will present a rationale for the use of multiple anti-angiogenic agents as a means of developing new chemopreventive protocols that result in reduced patient toxicity while maintaining similar clinical efficacies.

Interferon-gamma up-regulates intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 and recruits lymphocytes into the vagina of immune mice challenged with herpes simplex virus-2

Lymphocyte recruitment into tissues involves interactions between adhesion molecules on vascular endothelial cells and corresponding ligands on the lymphocyte surface. In the present study we investigated the expression of four endothelial addressins in the vagina and their possible up-regulation by interferon-gamma (IFN-gamma) in immune mice after vaginal challenge with herpes simplex virus type 2. The adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were minimally expressed in the vagina of non-immune mice with or without vaginal challenge and in immune mice before challenge, but both were up-regulated by IFN-gamma, directly or indirectly, in immune mice after challenge. Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) was detected in most vaginas but was not up-regulated by IFN-gamma in immune mice after virus challenge. E-selectin was not detected in any vaginas. The results suggest that ICAM-1 and VCAM-1 may be involved in rapid, IFN-gamma-mediated recruitment of lymphocytes to the vaginal mucosal of immune mice after local virus challenge.

The role of gamma interferon in immune resistance to vaginal infection by herpes simplex virus type 2 in mice

We investigated the role of interferon gamma (IFN-gamma) in a mouse model of immunity to vaginal infection by herpes simplex virus type 2 (HSV-2). Within 8 h after immune mice were challenged intravaginally with HSV-2, IFN-gamma concentrations in vaginal secretions reached levels that can be antiviral in vitro. This rapid synthesis of IFN-gamma occurred in immune-challenged mice but not in nonimmune-challenged mice, indicating that it required memory T cells. Immunostaining and in situ hybridization revealed that the IFN-gamma was synthesized by cells whose morphological appearance suggested that they were lymphocytes and macrophage-like cells in the mucosa. The presence of IFN-gamma in vaginal secretions was correlated with upregulation of MHC class II antigens in the epithelium and with vigorous (30-fold) recruitment of T and B lymphocytes into the vagina. In vivo administration of anti-IFN-gamma to immune mice 17 h before virus challenge blocked the subsequent appearance of IFN-gamma in vaginal secretions, blocked upregulation of class II antigens, blocked adherence of T cells to endothelium and their recruitment into the vagina, and markedly reduced immunity against reinfection of the vaginal epithelium.

Differential effects of IFN-beta1b on the proliferation of human vascular smooth muscle and endothelial cells

The effect of human interferon (IFN)-beta1b (Betaseron) on the proliferation of cultured human vascular smooth muscle and endothelial cells was tested in vitro. IFN-beta1b inhibited thymidine incorporation and growth of primary cultures of human aortic and coronary artery smooth muscle in a concentration-dependent manner. The same concentrations of IFN-beta1b did not inhibit thymidine incorporation or growth of primary cultures of human aortic or coronary artery endothelial cells. IFN-beta1b induced the expression of MxA (an antiviral protein induced by type I IFNs) in both smooth muscle and endothelial cells, suggesting that both cell types express receptors for type I IFNs. The growth-inhibitory effect of IFN-beta1b could be mimicked by commercially available human IFN-beta, but not by IFN-alpha2 or IFN-alpha8. The effect of IFN-beta1b was species specific, as it did not inhibit thymidine incorporation in aortic smooth muscle cells derived from pig, rabbit, rat, or mouse. The action of IFN-beta1b on smooth muscle cells persisted for at least 4 days following a 24 h preincubation with IFN-beta1b. Human vascular smooth muscle cells treated with IFN-beta1b did not release lactate dehydrogenase, nor did they show any morphologic change, suggesting that IFN-beta1b was not toxic to the human vascular smooth muscle cells. IFN-beta1b inhibited vascular smooth muscle growth while having no growth-inhibitory effect on endothelial cells obtained from the same blood vessel, making it a potential candidate for treating pathologic conditions where abnormal vascular smooth muscle proliferation is implicated, such as restenosis following balloon angioplasty or smooth muscle proliferation following vascular stenting.

Pulse treatment of human vascular endothelial cells with high doses of tumor necrosis factor and interferon-gamma results in simultaneous synergistic and reversible effects on proliferation and morphology

Regional administration of high doses of tumor necrosis factor (TNF), interferon gamma (IFNgamma) and melphalan to patients with advanced cancers of the limbs, results in rapid and specific tumor necrosis, while the normal adjacent tissues remain unaffected. The tumor vasculature is selectively destroyed by this treatment, and neovascular endothelial cells appear to be an early and specific target of TNF and IFNgamma. To further understand some of the cellular events underlying these in vivo effects, we have investigated the response of human macro- and microvascular endothelial cells in vitro, after exposure to high doses of TNF and IFNgamma (up to 40 x 10(3) U/ml each). TNF and IFNgamma synergistically inhibited endothelial-cell proliferation by up to 80% after 72 hr of treatment. Achievement of synergy required the simultaneous presence of both cytokines. A cytokine pulse as short as 30 min was sufficient to induce maximal growth inhibition measured after 48 hr. Both cytokines also induced progressive and dose-dependent elongation of the endothelial-cell morphology. The effects on endothelial-cell proliferation and morphology were reversible upon removal of the cytokines. Moreover, replating of treated cells onto a fresh substrate immediately resulted in re-acquisition of their normal shape. In contrast to the effect on cell proliferation, there was little or no effect on the rate of endothelial-cell apoptosis. The presented data extend reports on the effects of TNF and IFNgamma on human endothelial cells in vitro, and suggest that the in vivo disruption of the tumor vasculature caused by high doses of TNF and IFNgamma is not due to a direct cytotoxic effect on endothelial cells but occurs through an indirect mechanism.

Differences in angiogenic potential of classically vs alternatively activated macrophages

Macrophages (M phi) are important for angiogenesis during inflammation, wound repair, and tumor growth. However, well-characterized M phi subsets such as IFN-gamma-induced, classically activated (ca) M phi or IL-4/glucocorticoid-induced, alternatively activated (aa) M phi have not been thoroughly examined for a positive or negative association with angiogenesis. While caM phi populate early inflammatory reactions and high-turnover granulomas, aaM phi occur in healing wounds and chronic inflammation. In contrast to caM phi-dominated lesions, aaM phi-rich lesions are highly vascularized. In order to determine their angiogenic potential in vitro, these M phi subsets as well as unstimulated control macrophages (coM phi) were analyzed by RT-PCR for mRNA expression of 10 angiogenic factors after 3 and 6 days of culture. Early during activation, caM phi and coM phi expressed equal levels of 8 of 10 angiogenic factors (PDGF-A, MK, TNF-alpha, TGF-beta 1, PDGF-B, HGF, TGF-alpha, IGF-1), while aaM phi showed expression of only 4 of these factors (TGF-beta 1, PDGF-B, HGF, GF-1). After maturation, TGF-alpha and IGF-1 showed a shift in mRNA expression from caM phi to aaM phi resulting in a considerably enhanced expression of these factors in day-6 aaM phi as compared to day-6 caM phi and coM phi while PDGF-A, MK, and TNF-alpha remained suppressed in day 6 aaM phi. In all M phi subsets including controls, mRNA expression of aFGF and bFGF was minimal or absent while TGFG-beta 1, HGF, and ODGF-B were constitutively expressed. In order to functionally integrate angiogenic factor mRNA expression profiles, mitogenic activity of M phi subsets towards microvascular endothelium was assessed by cocultivation. Coculture experiments revealed that endothelial proliferation induced by aaM phi was 3.0-3.5x higher than induced by caM phi. In conclusion, mature aaM phi are well equipped to play an important role in protracted M phi-associated angiogenic processes. Presumably due to expression of predominantly angio-inhibitory cytokines such as TNF-alpha by caM phi but much less by aaM phi, caM phi exhibit only a low angiogenic potential in vitro and in vivo despite considerable expression of angiogenic factor mRNA.

The chemokine repertoire of human dermal microvascular endothelial cells and its regulation by inflammatory cytokines

Activation of endothelium is a critical event during the initiation of inflammatory processes and is associated with the induction of cell adhesion molecules and cytokines. The latter include chemotactically active cytokines (chemokines) that promote leukocyte diapedesis from the circulation to sites of evolving inflammation. In this study we evaluated the chemokine repertoire of human endothelial cells derived from the skin (HDMECs) and regulation of these chemokines by cytokines. HDMECs and an immortalized human dermal microvascular endothelial cell line, HMEC-1, were investigated for the expression of C-X-C and C-C chemokines at mRNA and protein levels. Upon stimulation with interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), both HDMECs and HMEC-1 expressed high levels of IL-8, GRO, and monocyte chemoattractant protein-1 (MCP-1). RANTES was only weakly induced; however, concomitant treatment with TNF-alpha and interferon-gamma (IFN-gamma) led to upregulation of RANTES, indicating a synergy between these two cytokines. The C-X-C chemokine IFN-inducible protein-10 was upregulated by IFN-gamma but not by other cytokines studied. Macrophage inflammatory protein-1alpha and beta, 1-309, and ENA-78 could not be induced. The chemokine repertoires of HDMECs and HMEC-1 were compared to those of human umbilical vein endothelium and found to be rather similar with the important exception that IFN-gamma and IL-4 up-regulated MCP-1 only in macrovascular endothelium. Our data indicate that HDMECs contribute to the dermal cytokine network by selective production of MCP-1, IL-8, GRO, RANTES, and IP-10, which may critically influence the site-specific recruitment of leukocyte subsets.

Cutaneous metastatic angiosarcoma with a lethal outcome, following radiotherapy for a cervical carcinoma

A cutaneous metastatic angiosarcoma was diagnosed in a 79-year-old woman 19 years after radiotherapy for a carcinoma of the uterine cervix. The diagnosis was confirmed by immunohistochemical staining (factor VIII-related antigen and BMA 120) and electron microscopic examination. Surgical treatment of the large tumour, which was situated in the gluteal region, was not feasible, but electron beam therapy resulted in complete remission. However, a further metastasis occurred in the inguinal region, and management by total excision, radiotherapy, and interferon-alpha treatment was unsuccessful. The patient died 28 months after the initial diagnosis of the neoplasm.

Interferon-beta downregulates interferon-gamma-induced class II MHC molecule expression and morphological changes in primary cultures of human brain microvessel endothelial cells

Regulation of class II MHC (Ia) antigen expression by interferons beta and gamma was studied in an in vitro model of the blood-brain barrier. Primary cultures of human brain microvessel endothelial cells were incubated with IFN-beta, gamma or a combination of the two cytokines and surface expression of class II MHC molecules was investigated with the immunogold silver staining technique and enzyme-linked immunosorbent assay. Treatment of monolayers with IFN-beta (100-6000 U/ml) failed to induce Class II MHC molecules. Co-incubation with IFN-gamma (100 U/ml), with or without pretreatment with IFN-beta, significantly inhibited the IFN-gamma-induced de novo expression in a concentration-dependent manner. Downregulation was less significant when incubation with both cytokines was preceded by 2-day treatment with IFN-gamma and was not observed in cultures incubated for an additional 4 days with IFN-gamma. Endothelial cells treated with IFN-gamma exhibited prominent morphological changes and frequent overlapping. These changes were not observed in the presence of either IFN-beta or both cytokines in the media. IFN-beta alone, or in combination with IFN-gamma, significantly inhibited the growth of endothelial cells, while only slight inhibition was observed with IFN-gamma. The results of these studies suggest that IFN-beta may function in modulating IFN-gamma-mediated immune responses in the human central nervous system at the level of the blood-brain barrier and this negative regulatory mechanism may be, at least in part, responsible for the recently reported beneficial effect of IFN-beta in relapsing-remitting multiple sclerosis.

Ultraviolet-A radiation induces adhesion molecule expression on human dermal microvascular endothelial cells

Ultraviolet radiation is capable of inducing numerous skin reactions. Considerable amounts of UVA radiation penetrate the epidermis and reach the microvascular endothelium of the papillary dermis. In order to investigate putative direct effects of UV radiation on endothelial cells, we studied adhesion molecule expression by immunostaining procedures and FACS analysis, following irradiation of normal human skin and cultured human dermal endothelial cells. Enhanced immunostaining for ICAM-1 and E-selectin was detected in biopsies taken after in vivo UVA and UVB irradiation, compared with non-irradiated control skin. On cultured human dermal endothelial cells, however, ICAM-1 and E-selectin were inducible by UVA but not UVB. The induction was dose-dependent, peaking at 20 J/cm2 for both adhesion molecules, and time-dependent, peaking after 6 and 24 h for E-selectin and ICAM-1, respectively. Expression of VCAM-1 and PECAM/EndoCAM/CD31 was unaffected by any UV-radiation modality. The functional integrity of irradiated cells was monitored by an exclusion assay of the fluorescent dye 7-AAD, and by staining for the cytoskeletal proteins actin and vimentin. Our results demonstrate that dermal microvascular endothelial cells are a critical and direct target of UVA, and suggest they may play a pivotal role in UV-induced inflammatory skin conditions.

Modulation of bovine microvascular endothelial cell proteolytic properties by inhibitors of angiogenesis

A tightly controlled increase in extracellular proteolysis, restricted both in time and space, is an important component of the angiogenic process, while anti-proteolysis is effective in inhibiting angiogenesis. By focussing on the plasminogen activator (PA)-plasmin system, the objective of the present studies was to assess whether previously described inhibitors of angiogenesis modify bovine microvascular endothelial cell proteolytic properties. We demonstrate that although synthetic angiostatic steroids (U-24067 and U-42129), heparin, suramin, interferon alpha-2a, and retinoic acid are all inhibitors of in vitro angiogenesis, each of these agents has distinct effects on the plasminogen-dependent proteolytic system. Specifically, angiostatic steroids and interferon alpha-2a reduce urokinase-type PA (u-PA) and PA inhibitor-1 activity, while heparin and retinoic acid increase u-PA activity. Suramin reduces cell-associated u-PA activity and greatly increases PAI-1 production at doses which induce monolayer disruption. These findings demonstrate that a spectrum of alterations in extracellular proteolysis is associated with anti-angiogenesis, and that anti-angiogenesis and anti-proteolysis are not necessarily correlated. A reduction in extracellular proteolysis would be expected to reduce invasion, whereas an increase in proteolysis might modulate the activity of inhibitory cytokines, which in turn could reduce endothelial cell proliferation and migration and inhibit angiogenesis. The spectrum of effects on different elements of the PA system observed in response to the agents assessed suggests that the role of modulations in extracellular proteolytic activity in anti-angiogenesis is likely to be varied and complex.

Alterations in human endothelial cell morphology, proliferation and function by a macrophage-derived factor

Changes in endothelial cell (EC) morphology occur at sites of physiological lymphocyte traffic and in areas of chronic inflammation. Previous studies have shown that EC shape changes also occur in vitro following exposure of EC monolayers to peripheral blood mononuclear cell (PBMC)-derived conditioned media (CM). In the present study, quantitative image analysis is used to define the cell of origin of the elongating factor(s), to examine changes in EC proliferation and function accompanying PBMC-induced human EC elongation and to identify the active PBMC-derived products responsible for this elongation. By separating mononuclear cells into subpopulations (macrophages, B cells and T cells) and adding conditioned media derived from these subpopulations to cultured ECs, the macrophage (M phi) is shown to be the primary cell of origin of the elongating factor(s). Furthermore, EC elongation is accompanied by both a dose-dependent decrease in cellular proliferation and an increase in prostacyclin production. These findings suggest that PBMC-induced changes in EC morphology may be associated with a shift from a proliferative state to a more secretory phase of the EC cycle. Finally, using recombinant factors it is shown that TNF alpha acting in combination with IL-1 may be the active PBMC-derived products which contribute to EC elongation.

VCAM-1 and ICAM-1 are expressed by Langerhans cells, macrophages and endothelial cells in oral lichen planus

Expression of intercellular adhesion molecule-1 (ICAM-1, CD54) and vascular cell adhesion molecule-1 (VCAM-1, CD106) was examined in oral lichen planus (OLP) and normal oral mucosa (NOM). Immunoperoxidase staining showed ICAM-1 expression by vascular endothelium in all biopsies of OLP and NOM whereas endothelial VCAM-1 staining was found in 2/7 NOM and 8/9 OLP. In the lamina propria of NOM occasional cells were ICAM-1 or VCAM-1 positive, and virtually no staining of intraepithelial dendritic cells was seen for either marker. Intraepithelial dendritic cells stained for ICAM-1 in 7/9 and VCAM-1 in 4/9 OLP biopsies. Double immunofluorescence showed dual labelling of Langerhans cells (LC) with CD1a and VCAM-1 in a further 5/12 cases of OLP, but there was no such staining in four NOM. This is the first report of LC staining with VCAM-1. Induction of ICAM-1 and VCAM-1 on LC and macrophages in OLP suggests these cells are activated and may contribute to the pathogenesis of OLP by presenting antigen to infiltrating lymphocytes.

Corticosteroids induce proliferation but do not influence TNF- or IL-1 beta-induced ICAM-1 expression of human dermal microvascular endothelial cells in vitro

The effects of hydrocortisone, dexamethasone, betamethasone 17-valerate and clobetasol propionate at concentrations of 10(-5)-10(-12) M on the proliferation of human dermal microvascular endothelial cells (HDMEC) were studied in vitro. In addition, confluent HDMEC were treated with TNF (1000 U/ml) or IL-1 beta (1000 U/ml) alone or in combination with the corticosteroids (10(-5) M, 10(-6) M) for 24 h, and cytokine-induced expression of intercellular adhesion molecule-1 (ICAM-1) was assessed by immunocytochemistry. Controls were treated either with growth medium or with the corticosteroids alone. All tested corticosteroids stimulated HDMEC growth after 4 and 6 days of treatment in a dose-dependent manner, as assessed by 3H-thymidine incorporation and the 4-methyl-umbelliferyl heptanoate (MUH) assay. The minimal effective concentration was 10(-9) M for hydrocortisone, 10(-10) M for dexamethasone and betamethasone, and 10(-12) M for clobetasol. In untreated and in corticosteroid-treated cultures, less than 5% of the cells expressed ICAM-1. TNF and IL-1 beta were strong inducers of ICAM-1 expression on 74% and 82% of the cells, respectively. None of the tested corticosteroids significantly influenced cytokine-induced ICAM-1 expression, suggesting that the anti-inflammatory effects of corticosteroids are not related to ICAM-1 modulation on HDMEC.

Cytokine-stimulated human dermal microvascular endothelial cells produce interleukin 6--inhibition by hydrocortisone, dexamethasone, and calcitriol

The effects of lipopolysaccharide (LPS), recombinant human tumor necrosis factor-alpha (TNF), recombinant human interleukin 1-beta (IL-1 beta), and interferon-gamma (IFN-gamma) on IL-6 production were determined by enzyme-linked immunosorbent assay (ELISA) and by Northern blot analysis in cultured human dermal microvascular endothelial cells (HDMEC). Unstimulated HDMEC did not produce significant amounts of IL-6, whereas lipopolysaccharide (LPS), TNF, and IL-1 beta were potent inducers of HDMEC-derived IL-6 production. Treatment with IFN-gamma had no effect. IL-1 beta stimulation resulted in pronounced IL-6 production after 4 h, followed by complete downregulation at the transcriptional level after 24 h. In contrast, LPS and TNF induced prolonged stimulation of IL-6 production by HDMEC as IL-6 mRNA transcripts were still detected after 24 h treatment and IL-6 protein was markedly increased at this timepoint. The effects of hydrocortisone, dexamethasone, calcitriol, acitretin, and cyclosporin A on TNF- or IL-1 beta-induced IL-6 production by HDMEC were determined by ELISA. Both hydrocortisone and dexamethasone dose-dependently inhibited the cytokine-induced IL-6 production, whereas the inhibition by calcitriol was less pronounced. In contrast, acitretin and cyclosporine A had no influence on cytokine-induced HDMEC IL-6 production. These results disclose dermal endothelial cells as a major source for the pro-inflammatory cytokine IL-6, involved in the regulation of inflammatory skin processes. As IL-6 seems to play a key role in the pathogenesis of psoriasis, the beneficial effects of corticosteroids and calcitriol in this disease may partly be explained by their ability to inhibit HDMEC-derived IL-6 production.

Inhibition of lymphocyte proliferation by bovine trophoblast protein-1 (type I trophoblast interferon) and bovine interferon-alpha I1

Bovine trophoblast protein-1 (bTP-1) is a Type I interferon secreted by the bovine trophoblast from about Day 15 of pregnancy. It is not known whether bTP-1 has functional properties in common with other interferons. The aim of the present study was to determine whether bTP-1 inhibits proliferation of lymphocytes induced by mitogens, mixed lymphocyte cultures (MLC) and interleukin-2 (IL-2) and, if so, whether this activity is similar to that of a related interferon, bovine interferon-alpha I1 (bIFN-alpha I1). Stimulation of lymphocyte proliferation caused by phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) was inhibited by bTP-1 and bIFN-alpha I1 without any reduction in cell viability. Maximum or near-maximum inhibition (less than 50%) was achieved at concentrations of 0.5-5.0 nM of bTP-1 and bIFN-alpha I1. Cells stimulated with PWM were less inhibited than cells stimulated with PHA and Con A. Both bTP-1 and bIFN-alpha I1 inhibited MLC to a greater degree than lectin-stimulated cells (maximum inhibition was 78% or greater). Also, bTP-1 and bIFN-alpha I1 slightly inhibited incorporation of [3H]thymidine ([3H]TdR) induced by the combination of phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA), and calcium ionophore A23187. Finally, bTP-1 and bIFN-alpha I1 had bimodal effects on incorporation of [3H]TdR by IL-2-induced lymphocytes. Incorporation of [3H]TdR was increased at 0.005 nM and 0.05 nM concentrations while higher concentrations caused a slight decrease in [3H]TdR incorporation. Results confirm that bTP-1 inhibits lymphocyte proliferation in a manner similar to that caused by the leukocyte-derived interferon, bIFN-alpha I1. Incomplete inhibition of mitogen-induced proliferation and differences in degree of inhibition between various stimulators suggest that bTP-1 and bIFN-alpha I1 preferentially inhibit certain lymphocyte subpopulations. Local inhibition of lymphocyte proliferation caused by bTP-1 may help protect the allogeneic conceptus from immune responses to fetal antigens or regulate the release of cytokines from endometrial lymphocytes.

Upregulation of intercellular adhesion molecule-1 (ICAM-1) expression in primary cultures of human brain microvessel endothelial cells by cytokines and lipopolysaccharide

The expression of intercellular adhesion molecule-1 (ICAM-1) by human cerebral endothelium was studied in primary cultures of human brain microvessel endothelial cells following treatment with bacterial lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interferon-gamma (IFN-gamma). Surface expression of ICAM-1 was examined with the immunogold silver staining technique. Intact cerebral endothelial cells constitutively express low levels of ICAM-1. Stimulation with LPS and cytokines induces upregulation of ICAM-1 which is minimal with IFN-gamma and maximal with LPS or a combination of IFN-gamma and TNF-alpha. Upregulation of ICAM-1 expression is concentration- and time-dependent, is observed as early as 4 h following incubation and persists for up to 72 h in the continuous presence of LPS or cytokines. The ICAM-1 expression is not reversed by 3 days after removal of the LPS or cytokines. These findings may be relevant to the interactions between leukocytes and brain microvessel endothelial cells in inflammatory and demyelinating diseases of the CNS.

Cytokine regulation of proliferation and ICAM-1 expression of human dermal microvascular endothelial cells in vitro

The effects of recombinant human interleukin 1 alpha (IL-1 alpha), interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), granulocyte/macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor-alpha (TNF) on the cell proliferation and the expression of intercellular adhesion molecule-1 (ICAM-1) were assessed in cultured human dermal microvascular endothelial cells (HDMEC). IL-1 alpha and IL-1 beta stimulated the proliferation of HDMEC in a dose-dependent manner, whereas in control experiments using human umbilical vein endothelial cells (HUVEC), IL-1 alpha and IL-1 beta did not stimulate HUVEC growth. Also GM-CSF stimulated the proliferation of HDMEC, whereas IL-6 did not affect endothelial cell growth in vitro. Treatment with IL-1 alpha, IL-1 beta, and TNF markedly increased the expression of ICAM-1 on HDMEC in a time- and dose-dependent manner, in contrast to IL-6 and GM-CSF. By pre-embedding immunoelectron microscopy, membrane-bound expression of ICAM-1 was visualized with pronounced labeling in areas of microvillous cell protrusions. The TNF-induced expression of ICAM-1 on HDMEC was blocked by co-incubation with a neutralizing antibody against TNF, but not with neutralizing antibodies against IL-1 alpha, IL-1 beta, or IL-6. In addition, co-incubation of HDMEC with TNF and the retinoid compound acitretin, dexamethasone, or indomethacin did not abrogate the TNF-induced ICAM-1 expression. These results disclose IL-1 as a major, multifunctional endothelial cell-targeted cytokine and further confirm the concept that pro-inflammatory cytokines exert differential regulatory effects on dermal microvascular endothelial cell proliferation and expression of cell-adhesion molecules.

Effect of interferon gamma on the sensitivity of bovine-papilloma-virus(BPV1)-transformed cell lines to cell-mediated cytotoxicity

The effect of interferon gamma (IFN gamma) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (BPV1) DNA was examined in a syngeneic mouse model. The overnight incubation of BPV1-transformed cell lines with 100 IU/ml IFN gamma did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (LAK) cells and by non-specific LAK-type effector cells induced by BPV-1-transformed cell lines. The treatment of two allogeneic lymphoid tumour cell lines, P815X2 and YAC-1, with IFN gamma either decreased or had no effect on their sensitivity to LAK-cell-mediated lysis.

A comprehensive two-dimensional gel protein database of noncultured unfractionated normal human epidermal keratinocytes: towards an integrated approach to the study of cell proliferation, differentiation and skin diseases

A two-dimensional (2-D) gel database of cellular proteins from noncultured, unfractionated normal human epidermal keratinocytes has been established. A total of 2651 [35S]methionine-labeled cellular proteins (1868 isoelectric focusing, 783 nonequilibrium pH gradient electrophoresis) were resolved and recorded using computer-aided 2-D gel electrophoresis. The protein numbers in this database differ from those reported in an earlier version due to changes in the scanning hardware (Celis et al., Electrophoresis 1990, 11, 242-254). Annotation categories reported include: "protein name" (listing 207 known proteins in alphabetical order), "basal cell markers", "differentiation markers", "proteins highly up-regulated in psoriatic skin", "microsequenced proteins" and "human autoantigens". For reference, we have also included 2-D gel (isoelectric focusing) patterns of cultured normal and psoriatic keratinocytes, melanocytes, fibroblasts, dermal microvascular endothelial cells, peripheral blood mononuclear cells and sweat duct cells. The keratinocyte 2-D gel protein database will be updated yearly in the November issue of Electrophoresis.

Effects of interferons on cultured human melanocytes in vitro: interferon-beta but not-alpha or -gamma inhibit proliferation and all interferons significantly modulate the cell phenotype

The effects of human recombinant interferon-alpha-2a (rIFN-alpha), natural interferon-beta (nIFN-beta) and recombinant interferon-gamma (rIFN-gamma) on the proliferation, morphology and antigen expression of cultured human melanocytes were studied in vitro. The investigations were performed in 12-O-tetradecanoylphorbol-13-acetate (TPA)- and serum-containing melanocyte growth medium (MGM), in TPA- and serum-free complete melanocyte medium (CMM) and its mitogen reduced variant (RMM). In MGM, none of these interferons inhibited the growth of normal melanocytes at concentrations 1-10,000 international units (IU)/ml over a period of 5 d. Only nIFN-beta, dose dependently, inhibited melanocyte proliferation in CMM and RMM in a 6- and 12-d assay (growth inhibition at 10,000 IU/ml; 77-80% of the controls, p less than 0.001). In contrast, rIFN-alpha and rIFN-gamma exerted no (RMM), or minor effects (CMM) on melanocyte proliferation (only in 12-d assays at 10,000 IU/ml: 24% and 21% of the controls respectively, p less than 0.01). In parallel experiments performed on melanoma cells, all three interferons were potent inhibitors of proliferation in a 5-d serum-free assay (growth inhibition at 10,000 IU/ml; rIFN-alpha 59%, nIFN-beta 78%, rIFN-gamma 56%, all p less than 0.001). In addition, nIFN-beta and also rIFN-gamma caused striking morphologic changes of normal melanocytes in vitro. Especially under greater than or equal to 10 IU/ml rIFN-gamma cytoplasmic spreading and flattening of the cultured melanocytes and their nuclei were seen, thus resembling melanoma cells in vitro. Untreated human melanocytes grown in MGM showed high expression of the melanoma-associated antigens HMB-45 (95-100%) and K.1.2 (40-100%), whereas the progression marker A.1.43 was present only on less than 5% of the cells. Cultured melanocytes were 95-100% positive for histocompatibility antigen class I (HLA-I), 30-75% were positive for ICAM-1, whereas they were negative for HLA-DR. After treatment with rIFN-alpha, increased expression of HLA-I antigens was found; nIFN-beta and rIFN-gamma decreased the labeling with HMB-45 (75-100%) and with K.1.2 (25-80%), whereby the expression of A.1.43 was found slightly increased (5-15%). The HLA class I antigens were upregulated by both nIFN-beta and rIFN-gamma, nIFN-beta being the most potent agent. Also, both nIFN-beta and rIFN-gamma increased the expression of ICAM-1 (nIFN-beta, 75-90%; rIFN-gamma, 90-95%) and induced de novo expression of HLA-DR antigen (nIFN-beta, 15-20%; rIFN-gamma, 65-95%).(ABSTRACT TRUNCATED AT 400 WORDS)

Cultivation of human dermal microvascular endothelial cells in vitro: immunocytochemical and ultrastructural characterization and effect of treatment with three synthetic retinoids

A new reliable and reproducible technique to culture endothelial cells from the small vessels and capillaries of human skin is introduced, and proliferation and differentiation of the growing cells are characterized. The endothelial origin of the culture cells was confirmed by light- and electron microscopy and by labelling with Ulex europaeus Agglutinin I and an antibody against Factor VIII-related antigen. Further immunocytochemical characterization showed that 92-100% of the cells were positive for beta 2-microglobulin and the entire cell population expressed vimentin, whereas cytokeratins, desmin, HLA-DR antigen, Leu 6 and S 100 protein, could not be detected. As vascular endothelium is a common site of inflammation and retinoids have been shown to be of good clinical efficacy in some chronic inflammatory skin diseases, we investigated the influence of etretinate, etretin and isotretinoin on proliferation and antigen expression of our culture cells. All retinoids applied inhibited proliferation of endothelial cells in a dose- and time-dependent manner whereas they induced neither HLA-DR nor intercellular adhesion molecule-1 (ICAM-1). Furthermore, none of the retinoids applied influenced the gamma-interferon-induced expression of these surface antigens on endothelial cells. Our results suggest that the action of retinoids in skin inflammation is not mediated by modulation of HLA-DR or ICAM-1. The cell culture technique described here is an interesting and reliable model for studying the influence of drugs on endothelial cell growth and differentiation in vitro.

Macrophage-derived angiogenesis factors

A majority of angiogenic factors has been shown to be produced by macrophages. This review will give a concise description of their biochemical nature, their isolation from macrophages and their angiogenic activity. Among the factors with mitogenic effects on endothelial cells are basic fibroblast growth factor (bFGF), transforming growth factor-alpha (TGF-alpha) and very probably insulin-like growth factor-1 (IGF-1). Other secretory products such as angiotropin and human angiogenic factor (HAF) are nonmitogenic but promote angiogenesis by inducing migration of endothelial cells. Prostaglandins, platelet-derived growth factor (PDGF), granulocyte-macrophage- and granulocyte-colony stimulating factor (GM-CSF, G-CSF), interleukin 6 (IL-6) and angiotensin converting enzyme (ACE) have also been shown to be angiogenic, but their mode of action is still to be clearly defined. As the extracellular matrix appears to be involved in the control of angiogenesis, macrophage-derived factors that can alter this structure via degradation or via the clotting system will also be discussed. Tumor necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1) and transforming growth factor-beta (TGF-beta) have complex actions on endothelial cells, and can partially inhibit angiogenesis. Among the factors which solely inhibit neovascularization are the interferons. As it is not known whether all of these factors play a role in angiogenesis in vivo attempts to detect them in situ during the course of neovascularization will be described. Finally macrophages will be discussed as cells that may not be mandatory for each phase of the angiogenic process but whose angiogenic capabilities are comprehensive and unsurpassed by any other cell.