Goswami, R.

Abstract Rationale : Airway remodeling in asthma involves increased airway smooth muscle (ASM) mass, changes to bronchial epithelial cell (BEC) layer, and increased fibrosis. ASM and BECs actively contribute by secreting growth factors and cytokines, regulating extracellular matrix (ECM) composition and enhancing cell proliferation/migration. Altering mechanisms which modulate remodeling presents a key to novel therapeutic strategies. BDNF increases ASM [Ca2+]i and contractility, and potentiates the effects of inflammation. Importantly, studies show that ASM is not only a target, but also a source of BDNF, raising the possibility of local autocrine/paracrine effects. Arginase 1 and 2 are expressed by BECs, but their roles in asthma are still under investigation with studies showing arginase 1 inhibition blunting epithelial remodeling and ASM hyperplasia. Knockdown of appealing targets such as ASM BDNF and epithelial arginases using small interfering RNA (siRNA) is a promising approach to combating inflammatory lung remodeling. Polymer based nanoparticles have been constructed which demonstrate cell-type specificity and high efficiency in delivering siRNA. Thus, we hypothesize that BDNF and arginases are central to airway remodeling and can be targeted via nanopartiacles.Methods: Primary human ASM and BEC cells from non-asthmatic vs. asthmatic individuals were obtained post-surgery from lung tissues after approval Mayo Clinic IRB. PONI-Guan NP were generated using block copolymer engineering. PCR, immunoblotting and ELISA were performed using standard techniques. Contractility studies were conducted in adult mouse precision cut lung slices. In vivo lung function studies were conducted in 6-8 week old mice, with or without mixed allergen (MA) treatment and Scireq Flexivent system. Results: PONI-Guan NP uptake demonstrates cell-type specificity in BEC/ASM co-culture and mouse lung. Arginase I/II and ECM expression is upregulated in BECs when exposed to BDNF and cytokines. In ASM, BDNF is increased in asthmatics compared to non-asthmatic controls; ECM expression is increased in response to BDNF and TNF-α. In BEC, PONI-Guan NP/siRNA inhibits Arg I/II expression, even in the presence of TNF-α. In ASM, TNF-α increases in BDNF secretion and ECM deposition are blunted by NP-delivered siRNA. PCLS and mouse lung function studies show contractility to MCh: effects suppressed by NP-delivered BDNF and Arg I siRNA. Conclusions: Our studies show the importance of BDNF/Arginase pathways in airway remodeling and efficacy of PONI-based siRNA delivery vectors in blunting remodeling processes.