Establishment of human mucosal microvascular endothelial cells from inferior turbinate in culture

Latent Collagenase Production by Cells Derived from Nasal Polyps in Culture

We investigated the interactions between nasal polyp-derived fibroblast-like cells (NPFCs) and nasal secretions to clarify the role of connective tissue metabolism in nasal and paranasal pathology, especially in chronic sinusitis. In response to stimulation by human interleukin 1 (IL-1), NPFCs produced latent collagenase. Collagenase production was also stimulated by nasal secretions from patients with chronic sinusitis in vitro, but not by nasal secretions from nasal allergic patients. A soluble factor was isolated from the nasal secretions of patients with chronic sinusitis by ammonium sulfate precipitation and Sephadex G-75 gel chromatography. High performance liquid chromatography indicated that the molecular weight of the active fraction was approximately 20,000 daltons. This factor affected NPFCs, but did not affect the endothelial cells derived from nasal mucosa in culture. Collagenase production by NPFCs was considerably inhibited by anti-IL-1 antibody. These results indicate that IL-1 is one major factor to prolong the nasal and paranasal inflammatory lesions.

Diesel exhaust particulates upregulate histamine receptor mRNA and increase histamine-induced IL-8 and GM-CSF production in nasal epithelial cells and endothelial cells

BACKGROUND

Histamine is the most important chemical mediator in the pathogenesis of nasal allergy. Diesel exhaust particulates (DEPs) are common air pollutants from diesel engine-powered car exhaust and cause chronic airway diseases. Recently we observed that the nasal reactivity to histamine was enhanced in diesel exhaust-exposed guinea-pigs. It was also revealed that epithelial cells and endothelial cells in the airway produce certain cytokines in response to histamine.

OBJECTIVE

We examined the effects of DEP extract on the expression of histamine H1 receptor (H1R) mRNA in human nasal epithelial cells (HNECs) and human mucosal microvascular endothelial cells (HMMECs), and on the production of IL-8 and GM-CSF induced by histamine.

METHODS

HNECs and HMMECs were isolated from human nasal mucosa specimens. HNEC and HMMEC monolayers were cultured in the presence or absence of DEP extract. The change in the expression of H1R mRNA was then evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and the Southern blot analysis. To investigate the effects of DEP extract on the histamine-induced cytokine production, HNEC and HMMEC monolayers were cultured in the presence or absence of DEP extract for 3-24 h. After three washes with PBS, they were then incubated with 10(-6) mol/L histamine for 24 h. The amounts of IL-8 and GM-CSF in the culture media were measured by enzyme-linked immunoabsorbent assay.

RESULTS

DEP extract increased the expression of H1R mRNA in both HNECs and HMMECs. The amount of IL-8 and GM-CSF, induced by histamine, was significantly higher in DEP extract pretreated HNECs and HMMECs than nontreated HNECs and HMMECs.

CONCLUSION

These results strongly suggest that DEP accelerates the inflammatory change by not only directly upregulating H1R expression but also increasing histamine-induced IL-8 and GM-CSF production.

The potential role of interleukin-13 in eosinophilic inflammation in nasal mucosa

BACKGROUND

Recent studies have revealed that interleukin (IL)-13, as well as IL-4, causes de novo surface expression of vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells of the umbilical vein and accelerates selective eosinophil migration. However, its role in allergic rhinitis remains to be clarified. Of particular interest is whether IL-13 upregulates VCAM-1 expression in human mucosal microvascular endothelial cells (HMMECs), to which eosinophils adhere in nasal mucosa.

METHODS

To understand the potential role of IL-13 in eosinophilic inflammation in nasal mucosa, we examined the effects of IL-13 on the adhesiveness between HMMECs and eosinophils.

RESULTS

IL-13 increased VCAM-1 expression in HMMECs, the adhesiveness of endothelial cells to eosinophils, and the transendothelial migration. On the other hand, IL-13 decreased the adhesiveness of eosinophils to HMMECs, and, as a result, accelerated eosinophil infiltration. Those effects are more potent than was those of IL-4. In addition, we also report that the amount of IL-13 in nasal mucosa was higher than that of IL-4.

CONCLUSIONS

These results strongly indicate that IL-13, as well as IL-4, may be important in eosinophilic inflammation in the nasal mucosa.

The effects of eotaxin on the surface adhesion molecules of endothelial cells and on eosinophil adhesion to microvascular endothelial cells

Eosinophil recruitment occurs in tissues as the result of allergic diseases. Human eotaxin is thought to be specific to eosinophils. In this study, we examined the effects of human eotaxin on the expression of adhesion molecules on nasal microvascular endothelial cells and on eosinophil adhesion to endothelial cells. Eotaxin upregulated the expression of ICAM-1 and VCAM-1 on human nasal mucosal microvascular endothelial cells (HMMEC), but not human umbilical vein endothelial cells (HUVEC). The eotaxin-induced eosinophil adhesion to HMMEC was increased at 10 ng/ml and significantly increased at the concentration of 100 ng/ml. On HUVEC, however, eotaxin did not induce increases of eosinophil adhesion. Anti-ICAM-1 and anti-VCAM-1 mAbs significantly decreased eotaxin-induced eosinophil adhesion. These results suggest that eotaxin regulates eosinophil accumulation to the nasal mucosa through its effect on the adhesion molecules on microvascular endothelial cells.

Histamine-induced calcium released from cultured human mucosal microvascular endothelial cells from nasal inferior turbinate

Changes in cytosolic Ca2+ concentration ([Ca2+]i) in cultured human mucosal microvascular endothelial cells (HMMECs) from nasal inferior turbinate were measured using a fluorescent Ca(2+)-sensitive dye, fura-2, and photometric fluorescence microscopy. Histamine caused a transient increase in intracellular free Ca2+ in cell populations and in individual cells, followed by a decrease to a sustained elevation. Histamine (100 microM) elevated [Ca2+]i in HMMECs up to 563 +/- 20 nM from a resting level of 60 +/- 45 nM (means +/- SD, n = 31). Promethazine (a histamine H1 receptor antagonist) inhibited [Ca2+]i increase during histamine stimulation, whereas cimetidine (a H2 receptor antagonist) and thioperamide (a H3 receptor antagonist) showed no inhibition. These results suggest that the histamine increase [Ca2+]i in HMMECs induces both a Ca2+ release from stores and a Ca2+ influx through activation of the H1 receptor.

Two-stage isolation procedure for obtaining homogenous populations of microvascular endothelial and mesothelial cells from human omentum

The human omentum is a highly vascularized tissue often advocated as a source of human microvascular endothelial (HOME) cells. The omentum also contains mesothelial (MESO) cells and isolation protocols published to date do not describe a separation of the two cell populations. Using a two-stage collagenase digestion procedure, homogenous populations of HOME and MESO cells are obtained from the same omental tissue sample. HOME and MESO cells are both simple squamous epithelial cells and consequently are often difficult to discriminate between based on morphology and reactivity with many of the conventional endothelial and mesothelial cell markers. Both HOME and MESO cells form typical cobblestone, contact-inhibited monolayers, metabolize DiI-Ac-LDL, and are immunoreactive to von Willebrand Factor and Ulex europeaus I lectin. However, MESO cells are distinguishable from HOME cells based upon their expression of cytokeratins. Moreover, HOME cells and not MESO cells form capillary-like structures when cultured on Matrigel. It appears that HOME and MESO cells share many phenotypic properties, but are distinguishable from one another based upon a comprehensive panel of endothelial and mesothelial markers. Both cell types should be useful for studying the biology and pathology of the human microvasculature in vitro.

RANTES production in nasal epithelial cells and endothelial cells

BACKGROUND

It is well documented that the chemokine that is regulated upon activation, normal T expressed and presumably secreted, RANTES, is produced by macrophages, platelets, fibroblasts, and renal tubular epithelial cells. Recently, however, production of RANTES by vascular endothelium and airway epithelial cells was demonstrated in human umbilical vein endothelial cells (HUVECs) and epithelial cell lines.

OBJECTIVE

This investigation was aimed at determining whether human nasal epithelial cells (HNECs) and human mucosal microvascular endothelial cells (HMMECs) produce RANTES when they are stimulated by several cytokines.

METHODS

HNECs and HMMECs were isolated from nasal mucosa and subsequent continuous subcultures and were stimulated either by IL-1 beta or by the combination of tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma).

RESULTS

After the combined stimulation by TNF-alpha and IFN-gamma, HNECs and HMMECs dramatically produced RANTES, as previously observed in HUVECs and bronchial epithelial cell line BEAS-2B. IL-1 beta also increased RANTES production to a lesser extent. We also demonstrated that the amount of RANTES induced by TNF-alpha and IFN-gamma was higher in HNECs and HMMECs obtained from patients with nasal allergy than in those from patients without allergy.

CONCLUSION

RANTES from HNECs and HMMECs likely plays a critical role in eosinophil infiltration of the nasal mucosa in subjects with nasal allergy.

Human microvessel endothelial cells: isolation, culture and characterization

Over recent years, interest in endothelial cell biology has increased dramatically with our ability to grow and study endothelial cells in vitro. While large veins and arteries remain a quick and convenient source of endothelial cells, the great morphological, biochemical and functional heterogeneity that endothelial cells express has necessitated the development of techniques to isolate microvessel endothelial cells from different tissues to create more realistic in vitro models. The majority of isolation procedures employ selective methods to enrich microvessel endothelial cells from tissue homogenates directly, or after a period in culture. These include sieving/filtration, manual weeding, isopycnic centrifugation, selective growth media, and the use of flow cytometry or magnetic beads coupled with specific endothelial cell markers. The establishment of pure endothelial cell populations is important for studying their biochemistry and physiology and there are many morphological, immunological and biochemical criteria which can be used to characterize human endothelial cells. These range from classical markers such as von Willebrand Factor and angiotensin-converting enzyme to novel markers like platelet endothelial cell adhesion molecule-1 (CD31) and the expression of E-selectin on cytokine-activated endothelial cells.

Type IV collagenase(s) and TIMPs modulate endothelial cell morphogenesis in vitro

It has been proposed that proteases are important in endothelial cell behavior. We examined the contribution of the gelatinase/type IV collagenase system in an in vitro model of endothelial differentiation. Human umbilical vein endothelial cells rapidly align and form networks of tubes when cultured on a basement membrane preparation, Matrigel. Zymograms of culture supernates demonstrate a 72-kD and a 92-kD gelatinase activity; the cells produce most of the 72-kD gelatinase, whereas the 92-kD activity is derived entirely from the Matrigel. Addition of antibodies against type IV gelatinase/collagenase decreases the area of the tube network. Both tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-2, similarly decrease tube formation when added to cultures. Conversely, exogenous recombinant 72-kD gelatinase increases tube-forming activity. The effects of the anti-gelatinase antibodies and the TIMPs are not additive. Inhibition by either antibodies or TIMPs is greatest when they are added at culture initiation, suggesting that the protease activity is important in the early steps of morphogenesis. However, culture of the cells on Matrigel does not increase early expression of mRNA for the 72-kD gelatinase. Expression of message for the enzyme actually decreases during the course of the assay, while transcription of mRNAs for TIMPs increases, further supporting the concept that collagenases facilitate an early event in tube formation. These data demonstrate that gelatinase/type IV collagenase activity is important in endothelial cell morphogenesis on Matrigel, and suggest a role for collagenases in formation of new capillaries in vivo.

Isolation and characterization of microvessel endothelial cells from human mammary adipose tissue

A method for the isolation and long-term culture of human microvessel endothelial cells from mammary adipose tissue (HuMMEC) obtained at breast reduction surgery has been developed. Pure cultures of HuMMEC were isolated by sequential digestion of the fat with collagenase and trypsin followed by specific selection of microvessel fragments with Ulex europaeus agglutinin-1 coated magnetic beads (Dynabeads). The resulting cells formed contact-inhibited monolayers on gelatin and fibronectin substrates and capillary-like "tubes" on Matrigel; they also expressed von Willebrand factor, angiotensin-converting enzyme, and accumulated acetylated low density lipoprotein. Further immunofluorescence characterization revealed the presence of antigens for the endothelial cell specific monoclonal antibodies EN4 and H4-7/33. In addition, the origin of these cells was confirmed by the demonstration of the cell adhesion molecules, platelet endothelial cell adhesion molecule-1 (CD31), and endothelial leukocyte adhesion molecule-1 (ELAM-1/E-selectin) upon stimulation with tumor necrosis factor (TNF) alpha. HuMMEC were found to express-1 ELAM-1 at lower levels of TNF alpha (< 10 ng/ml) than required by human umbilical vein endothelial cells. These cells should provide a useful in vitro model for studying various aspects of microvascular biology and pathology.

Retention fluids of chronic sinusitis induce neutrophil adherence to microvascular endothelial cells

The adherence of circulating leukocytes to the vascular endothelium is a critical step in the emigration of leukocytes through blood vessel walls to inflammatory lesions. The influence of nasal secretions on the adherence of neutrophils to the vascular endothelium was investigated using monolayers of human mucosal microvascular endothelial cells derived from the inferior turbinate. Preincubation of vascular endothelial cells with retention fluids from the maxillary sinus of the patients with chronic sinusitis showed increased neutrophil adherence. Recombinant IL-1 beta was also tested and found to induce adherence of neutrophils to human mucosal microvascular endothelial cells. However, no adhesive effect was observed with the nasal secretions of nasal allergy. An enzyme-linked immunosorbent assay detected considerable amounts of IL-1 beta in the chronic sinusitis retention fluids, while the amounts of IL-1 alpha and TNF-alpha were very low. The increased adhesion of the neutrophils by the retention fluids of chronic sinusitis was also neutralized by the incubation with anti-IL-1 beta antibody in a dose dependent manner. These findings suggest that IL-1 beta in the paranasal secretion of chronic sinusitis induces the adherence of neutrophils to vascular endothelium and subsequent infiltration of neutrophils in the paranasal sinuses, thus contributing to the persistence of chronic sinusitis.

Intracellular mechanisms involved in basement membrane induced blood vessel differentiation in vitro

The extracellular matrix, particularly basement membranes, plays an important role in angiogenesis (blood vessel formation). Previous work has demonstrated that a basement membranelike substrate (Matrigel) induces human umbilical vein endothelial cells to rapidly form vessel-like tubes (Kubota, et al., 1988; Grant et al., 1989b); however, the precise mechanism of tube formation is unclear. Using this in vitro model, we have investigated morphologic changes occurring during tube formation and the cytoskeletal and protein synthesis requirements of this process. Electron microscopy showed that endothelial cells attach to the Matrigel surface, align, and form cylindrical structures that contain a lumen and polarized cytoplasmic organelles. The cytoskeleton is reorganized into bundles of actin filaments oriented along the axis of the tubes and is located at the periphery of the cells. The addition of colchicine or cytochalasin D blocked tube formation, indicating that both microfilaments and microtubules are involved in this process. Cycloheximide blocked tube formation by 100%, indicating that the process also required protein synthesis. In particular, collagen synthesis seems to be required for tube formation because cis-hydroxyproline inhibited tube formation, whereas either the presence of ascorbic acid or the addition of exogenous collagen IV to the Matrigel increased tube formation. Our results indicate that endothelial cell attachment to Matrigel induces the reorganization of the cytoskeleton and elicits the synthesis of specific proteins required for the differentiated phenotype of the cells.