Integrin α2β1 regulates collagen I tethering to modulate hyperresponsiveness in reactive airway disease models

IL-13 and IL-17A Activate β1 Integrin through an NF-kB/Rho kinase/PIP5K1γ pathway to Enhance Force Transmission in Airway Smooth Muscle

Integrin activation resulting in enhanced adhesion to the extracellular matrix plays a key role in fundamental cellular processes. Although G-protein coupled receptor-mediated integrin activation has been extensively studied in non-adherent migratory cells such as leukocytes and platelets, much less is known about the regulation and functional impact of integrin activation in adherent stationary cells such as airway smooth muscle. Here we show that two different asthmagenic cytokines, IL-13 and IL-17A, activate type I and IL-17 cytokine receptor families respectively, to enhance adhesion of muscle to the matrix. These cytokines also induce activation of β1 integrins as detected by the conformation-specific antibody HUTS-4. Moreover, HUTS-4 binding is significantly increased in the smooth muscle of patients with asthma compared to healthy controls, suggesting a disease-relevant role for aberrant integrin activation. Indeed, we find integrin activation induced by a β1 activating antibody, the divalent cation manganese, or the synthetic peptide β1-CHAMP, dramatically enhances force transmission in collagen gels, mouse tracheal rings, and human bronchial rings even in the absence of cytokines. We further demonstrate that cytokine-induced activation of β1 integrins is regulated by a common pathway of NF-κB-mediated induction of RhoA and its effector Rho kinase, which in turn stimulates PIP5K1γ-mediated synthesis of PIP2 resulting in β1 integrin activation. Taken together, these data identify a previously unknown pathway by which type I and IL-17 cytokine receptor family stimulation induces functionally relevant β1 integrin activation in adherent smooth muscle and help explain the exaggerated force transmission that characterizes chronic airways diseases such as asthma.

Two-Dimensional Peptide Assembly via Arene-Perfluoroarene Interactions for Proliferation and Differentiation of Myoblasts

Supramolecular assembly based on aromatic interactions can provide well-defined nanostructures with an understanding of intermolecular interactions at the molecular level. The peptide assembly via a supramolecular approach can overcome the inherent limitations of bioactive peptides, such as proteolytic degradations and rapid internalizations into the cytosol. Although extensive research has been carried out on supramolecular peptide materials with a two-dimensional (2D) structure, more needs to be reported on biological activity studies using well-defined 2D peptide materials. Physical and chemical properties of the 2D peptide assembly attributed to their large surface area and flexibility can show low cytotoxicity, enhanced molecular loading, and higher bioconjugation efficiency in biological applications. Here, we report supramolecular 2D materials based on the pyrene-grafted amphiphilic peptide, which contains a peptide sequence (Asp-Gly-Glu-Ala; DGEA) that is reported to bind to the integrin α2β1 receptor in 2D cell membranes. The addition of octafluoronaphthalene (OFN) to the pyrene-grafted peptide could induce a well-ordered 2D assembly by face-centered arene-perfluoroarene stacking. The DGEA-peptide 2D assembly with a flat structure, structural stability against enzymatic degradations, and a larger size can enhance the proliferation and differentiation of muscle cells via continuous interactions with cell membrane receptors integrin α2β1 showing a low intracellular uptake (15%) compared to that (62%) of the vesicular peptide assembly. These supramolecular approaches via the arene-perfluoroarene interaction provide a strategy to fabricate well-defined 2D peptide materials with an understanding of assembly at the molecular level for the next-generation peptide materials.

Pathobiology of Airway Remodeling in Asthma: The Emerging Role of Integrins

Airway remodeling is a complex clinical feature of asthma that involves long-term disruption and modification of airway architecture, which contributes significantly to airway hyperresponsiveness (AHR) and lung function decline. It is characterized by thickening of the airway smooth muscle layer, deposition of a matrix below the airway epithelium, resulting in subepithelial fibrosis, changes within the airway epithelium, leading to disruption of the barrier, and excessive mucous production and angiogenesis within the airway wall. Airway remodeling contributes to stiffer and less compliant airways in asthma and leads to persistent, irreversible airflow obstruction. Current asthma treatments aim to reduce airway inflammation and exacerbations but none are targeted towards airway remodeling. Inhibiting the development of airway remodeling or reversing established remodeling has the potential to dramatically improve symptoms and disease burden in asthmatic patients. Integrins are a family of transmembrane heterodimeric proteins that serve as the primary receptors for extracellular matrix (ECM) components, mediating cell-cell and cell-ECM interactions to initiate intracellular signaling cascades. Cells present within the lungs, including structural and inflammatory cells, express a wide and varying range of integrin heterodimer combinations and permutations. Integrins are emerging as an important regulator of inflammation, repair, remodeling, and fibrosis in the lung, particularly in chronic lung diseases such as asthma. Here, we provide a comprehensive summary of the current state of knowledge on integrins in the asthmatic airway and how these integrins promote the remodeling process, and emphasize their potential involvement in airway disease.