IL-32 promotes angiogenesis

Claudia Annelie Nold, Ina Rudloff, Yvonne Baumer, Menotti Ruvo, Daniela Marasco, Paolo Botti, Laszlo Farkas, Steven Cho, Jarod A Zepp, Tania Azam, Hannah Dinkel, Brent E Palmer, William A Boisvert, Carlyne D Cool, Laima Taraseviciene-Stewart, Bas Heinhuis, Leo A B Joosten, Charles A Dinarello, Norbert F Voelkel, Marcel Friedrich Nold

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74 Citations (Scopus)


IL-32 is a multifaceted cytokine with a role in infections, autoimmune diseases, and cancer, and it exerts diverse functions, including aggravation of inflammation and inhibition of virus propagation. We previously identified IL-32 as a critical regulator of endothelial cell (EC) functions, and we now reveal that IL-32 also possesses angiogenic properties. The hyperproliferative ECs of human pulmonary arterial hypertension and glioblastoma multiforme exhibited a markedly increased abundance of IL-32, and, significantly, the cytokine colocalized with integrin alphaVbeta3. Vascular endothelial growth factor (VEGF) receptor blockade, which resulted in EC hyperproliferation, increased IL-32 three-fold. Small interfering RNA-mediated silencing of IL-32 negated the 58 proliferation of ECs that occurred within 24 h in scrambled-transfected controls. Reduction of IL-32 neither affected apoptosis (insignificant changes in Bak-1, Bcl-2, Bcl-xL, lactate dehydrogenase, annexin V, and propidium iodide) nor VEGF or TGF-beta levels, but siIL-32-transfected adult and neonatal ECs produced up to 61 less NO, IL-8, and matrix metalloproteinase-9, and up to 3-fold more activin A and endostatin. In coculture-based angiogenesis assays, IL-32gamma dose-dependently increased tube formation up to 3-fold; an alphaVbeta3 inhibitor prevented this activity and reduced IL-32gamma-induced IL-8 by 85 . In matrigel plugs loaded with IL-32gamma, VEGF, or vehicle and injected into live mice, we observed the anticipated VEGF-induced increase in neocapillarization (8-fold versus vehicle), but unexpectedly, IL-32gamma was equally angiogenic. A second signal such as IFN-gamma was required to render cells responsive to exogenous IL-32gamma; importantly, this was confirmed using a completely synthetic preparation of IL-32gamma. In summary, we add angiogenic properties that are mediated by integrin alphaVbeta3 but VEGF-independent to the portfolio of IL-32, implicating a role for this versatile cytokine in pulmonary arterial hypertension and neoplastic diseases.
Original languageEnglish
Pages (from-to)589 - 602
Number of pages14
JournalJournal of Immunology
Issue number2
Publication statusPublished - 2014

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