Polymeric nanoparticle-mediated siRNA delivery into primary human bronchial airway cells

Area of Science:

• Biomaterials Science
• Nanotechnology
• Respiratory Medicine

Background:

• Small interfering RNAs (siRNA) offer therapeutic potential for airway diseases by targeting protein expression.
• Effective and safe delivery of siRNA into bronchial epithelial (BEC) and airway smooth muscle (ASM) cells remains a challenge.
• Need for non-toxic delivery systems that protect siRNA and facilitate cellular uptake.

Purpose of the Study:

• To investigate the mechanisms of siRNA delivery by guanidinium-functionalized poly(oxanorbornene)imide polymer (PONI-Guan) nanoparticles in BEC and ASM cells.
• To assess the safety and efficacy of PONI-Guan nanoparticles for siRNA delivery in the context of airway diseases.
• To elucidate the cellular uptake pathways involved in PONI-Guan nanoparticle-mediated siRNA delivery.

Main Methods:

• PONI-Guan polymers were engineered to self-assemble with siRNA via electrostatic interactions.
• Cellular uptake studies were conducted using various endocytosis inhibitors (methyl-β-cyclodextrin, dynasore, latrunculin B, etc.) at different guanidinium/phosphate (G/P) ratios.
• Cell viability, barrier integrity (transepithelial electrical resistance), and gene silencing efficacy (mRNA and protein expression) were evaluated.

Main Results:

• Nanoparticle uptake was significantly reduced by methyl-β-cyclodextrin and dynasore, suggesting caveolar or macropinocytosis pathways.
• Minimal toxicity was observed for PONI-Guan nanoparticles at G/P ratios of 20 and 30, with stable barrier integrity.
• Effective gene silencing was achieved for BDNF siRNA in ASM cells and Arginase 1 and 2 siRNA in BEC cells.

Conclusions:

• PONI-Guan nanoparticles provide a safe and effective platform for siRNA delivery in human bronchial cells.
• The primary uptake mechanisms involve caveolar and macropinocytosis pathways.
• This technology holds significant promise for developing novel siRNA-based therapeutics for airway diseases such as asthma and COPD.