ABSTRACT: IL-32 is a proinflammatory cytokine involved in various chronic inflammatory diseases. Chronic airway inflammation in asthmatic patients results in structural airway changes, including angiogenesis. Vascular endothelial growth factor (VEGF) is a key inducer of angiogenesis in the airways of asthmatic patients.
The aim of the study was to investigate the expression and function of IL-32 in patients with angiogenesis and asthma.
The expression and regulation of IL-32 in normal human bronchial epithelial (NHBE) cells was analyzed by using RT-PCR, ELISA, Western blotting, immunofluorescent staining, and flow cytometry. After knockdown of IL-32 in NHBE cells by small interfering RNA (siRNA) transfections, VEGF secretion was quantified by means of ELISA. New blood vessel formation was determined with human umbilical vein endothelial cells by culturing with supernatants from IL-32 siRNA-transfected NHBE cells. IL-32 was determined in serum and induced sputum samples of asthmatic patients and healthy control subjects by means of ELISA.
IL-32 is expressed in NHBE cells on stimulation with IFN-γ, TNF-α, T(H)1 cells, and rhinovirus. Inhibition of IL-32 expression resulted in significantly increased secretion of the proangiogenic factors VEGF and platelet-derived growth factor by NHBE cells. Human umbilical vein endothelial cells cultured in supernatants from IL-32 siRNA-transfected NHBE cells showed enhanced in vitro angiogenesis. IL-32 is detectable in induced sputum from asthmatic patients. IL-32 serum levels were significantly higher in asthmatic patients compared with those seen in healthy control subjects and correlated with response to asthma treatment.
IL-32 is induced by IFN-γ, TNF-α, T(H)1 cells, and rhinovirus in bronchial epithelial cells. It inhibits angiogenesis, and its serum levels are associated with a good treatment response in asthmatic patients.
The Journal of allergy and clinical immunology 02/2012; 129(4):964-73.e7. · 9.17 Impact Factor
ABSTRACT: Keratinocyte (KC) apoptosis is an important mechanism of eczema and spongiosis in patients with atopic dermatitis (AD) and is mediated by IFN-gamma, which is secreted by T(H)1 cells. IL-32 is a proinflammatory cytokine that is involved in the inflammatory processes of rheumatoid arthritis, chronic obstructive pulmonary disease, and Crohn disease. Recently, it was shown that upregulation of IL-32 induces apoptosis.
The aim of the study was to investigate the expression and function of IL-32 in patients with AD.
The expression of IL-32 in KCs was analyzed by means of RT-PCR, ELISA, and flow cytometry. Transfections of small interfering RNA were performed in primary KCs, and apoptosis was analyzed by means of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling, annexin-V, and 7-amino actinomycin D stainings. Immunofluorescence stainings were used to detect IL-32 in skin biopsy specimens, and serum levels of IL-32 were analyzed by means of ELISA.
We report that IL-32 is expressed in human primary KCs on stimulation with IFN-gamma, TNF-alpha, and T(H)1 cells in contrast to T(H)2, regulatory T (Treg), or T(H)17 cells, which showed no effect. Transfection of primary KCs and artificial skin equivalents with small interfering RNA to IL-32, which resulted in a clear decrease in IL-32 expression, significantly reduced KC apoptosis. Immunofluorescence staining demonstrated that IL-32 was expressed in AD lesional skin, whereas it was present in neither skin biopsy specimens from healthy donors nor in lesional skin from patients with psoriasis. Serum levels of IL-32 from patients with AD correlated with disease severity, but increased serum levels of IL-32 were also detected in asthmatic patients.
The present study demonstrates KCs as a source of IL-32, which modulates KC apoptosis and contributes to the pathophysiology of AD.
The Journal of allergy and clinical immunology 03/2010; 125(4):858-865.e10. · 9.17 Impact Factor
ABSTRACT: Forkhead box p3 (FOXP3) is known to program the acquisition of suppressive capacities in CD4(+) regulatory T cells (Treg), whereas its role in CD8(+) T cells is unknown. The current study investigates whether FOXP3 also acts as a Treg master switch in peripheral blood and tonsillar CD8(+) T cells. Single-cell analyses reveal the existence of a FOXP3(+)CD8(+) population in human tonsils, whereas FOXP3(+)CD8(+) T cells are rarely detected in peripheral blood. Tonsillar FOXP3(+)CD8(+) T cells exhibit a Treg phenotype with high CTLA-4 and CD45RO and low CD127 and CD69 expression. Interestingly, the tonsillar FOXP3(+)CD8(+) T cells are mostly CD25(negative) and some cells also express the proinflammatory cytokines TNF-alpha, IFN-gamma, or IL-17A. Particularly, IL-17A-expressing cells are present among FOXP3(+)CD8(+) T cells. Even though FOXP3 expression is at the detection limit in peripheral blood CD8(+) T cells ex vivo, it can be induced in vitro in naive CD8(+) T cells by polyclonal stimulation. The induced FOXP3(+)CD8(+) T cells are predominantly CD25(high) and CD28(high) and similar to tonsillar cells, they produce high levels of TNF-alpha, IFN-gamma, and granzyme B. However, IL-4 expression is mutually exclusive and IL-17A expression is not detectable. These FOXP3(+)CD8(+) T cells suppress the proliferation of CD4(+) T cells in cocultures, while showing no direct cytotoxic activity. In conclusion, the current study characterizes FOXP3-expressing CD8(+) T cells from human tonsils and shows that in vitro activation leads to FOXP3 expression in CD8(+) T cells and gain of suppressive activity.
The Journal of Immunology 03/2009; 182(4):2124-30. · 5.79 Impact Factor