IL-9 Induces VEGF Secretion from Human Mast Cells and IL-9/IL-9 Receptor Genes Are Overexpressed in Atopic Dermatitis

Interleukin 9 (IL-9) has been implicated in mast cell-related inflammatory diseases, such as asthma, where vascular endothelial growth factor (VEGF) is involved. Here we report that IL-9 (10–20 ng/ml) induces gene expression and secretion of VEGF from human LAD2. IL-9 does not induce mast cell degranulation or the release of other mediators (IL-1, IL-8, or TNF). VEGF production in response to IL-9 involves STAT-3 activation. The effect is inhibited (about 80%) by the STAT-3 inhibitor, Stattic. Gene-expression of IL-9 and IL-9 receptor is significantly increased in lesional skin areas of atopic dermatitis (AD) patients as compared to normal control skin, while serum IL-9 is not different from controls. These results imply that functional interactions between IL-9 and mast cells leading to VEGF release contribute to the initiation/propagation of the pathogenesis of AD, a skin inflammatory disease

IL-9 Induces VEGF Secretion from Human Mast Cells and IL-9/IL-9 Receptor Genes Are Overexpressed in Atopic Dermatitis

Interleukin 9 (IL-9) has been implicated in mast cell-related inflammatory diseases, such as asthma, where vascular endothelial growth factor (VEGF) is involved. Here we report that IL-9 (10-20 ng/ml) induces gene expression and secretion of VEGF from human LAD2. IL-9 does not induce mast cell degranulation or the release of other mediators (IL-1, IL-8, or TNF). VEGF production in response to IL-9 involves STAT-3 activation. The effect is inhibited (about 80%) by the STAT-3 inhibitor, Stattic. Gene-expression of IL-9 and IL-9 receptor is significantly increased in lesional skin areas of atopic dermatitis (AD) patients as compared to normal control skin, while serum IL-9 is not different from controls. These results imply that functional interactions between IL-9 and mast cells leading to VEGF release contribute to the initiation/propagation of the pathogenesis of AD, a skin inflammatory disease

(A) IL-9 gene expression in the skin of AD affected (n = 16) and normal healthy controls (n = 12).

<p>(B) IL-9 receptor (IL-9r) gene expression in skin of AD affected (n = 19) skin and normal healthy controls (n = 20). Relative quantities of mRNA expression were measured by quantitative RT-PCR and normalized to GAPDH. TaqMan was performed with cDNA reverse transcribed from 100 ng RNA from each sample. *p<0.05.</p

IL-9 stimulates VEGF production in human mast cells.

<p>(A) Gene expression. LAD2 cells were stimulated with IL-9 for 6 hrs, RNA was extracted and relative VEGF mRNA levels were determined by real-time PCR. (B) Protein release. LAD2 cells were stimulated with the indicated concentration of IL-9 (10–20 ng/ml) for 48 hrs. VEGF was measured in the supernatant fluid by ELISA. Data are the mean ± SD of 3 separate experiments performed in triplicate (*<i>P</i><0.05 versus unstimulated cells).</p

IL-9 serum level in AD patients (n = 18) and controls (n = 39).

<p>IL-9 level was determined using Millipex microbead assay and the measurements were performed blind by Millipore (St. Charles, MI).</p

(A) IL-9 induces STAT3 phosphorylation in LAD2 cells.

<p>Cells were stimulated with IL-9 for up to 20 min. Phospho-STAT3 levels in the cell lysates were determined by ELISA. (B) STAT3 inhibitor Stattic inhibits IL-9-induced VEGF release from LAD2 cells. LAD2 cells were pre-incubated for 30 min with the indicated concentrations of Stattic. Cells were stimulated with IL-9 (10–20 ng/ml) for 24 h and supernatant VEGF was measured by ELISA. Data are representative of similar experiments.</p

Actionable Cytopathogenic Host Responses of Human Alveolar Type 2 Cells to SARS-CoV-2

Human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causative pathogen of the COVID-19 pandemic, exerts a massive health and socioeconomic crisis. The virus infects alveolar epithelial type 2 cells (AT2s), leading to lung injury and impaired gas exchange, but the mechanisms driving infection and pathology are unclear. We performed a quantitative phosphoproteomic survey of induced pluripotent stem cell-derived AT2s (iAT2s) infected with SARS-CoV-2 at air-liquid interface (ALI). Time course analysis revealed rapid remodeling of diverse host systems, including signaling, RNA processing, translation, metabolism, nuclear integrity, protein trafficking, and cytoskeletal-microtubule organization, leading to cell cycle arrest, genotoxic stress, and innate immunity. Comparison to analogous data from transformed cell lines revealed respiratory-specific processes hijacked by SARS-CoV-2, highlighting potential novel therapeutic avenues that were validated by a high hit rate in a targeted small molecule screen in our iAT2 ALI system. [Display omitted] •SARS-CoV-2 infection in induced lung cells is characterized by phosphoproteomics•Analysis of response reveals host cell signaling and protein expression profile•Comparison to studies in undifferentiated cell lines shows unique pathology in iAT2s•Systems-level predictions find druggable pathways that can impede viral life cycle Hekman et al. describe how a layer of primary stem cells (iAT2s) recapitulating lung biology responds to infection with SARS-CoV-2. They compare their work to previous studies with immortalized cell lines. Their data predict what effect the virus has on a lung cell and which drugs may slow infection