Small interfering RNA expression inhibits avian infectious bronchitis virus replication and inflammatory response

Area of Science:

• Veterinary Virology
• Molecular Biology
• Immunology

Background:

• Avian infectious bronchitis virus (IBV) causes significant economic losses in poultry farming due to reduced weight gain and increased mortality.
• Effective control strategies against IBV are crucial for the health and productivity of commercial chicken flocks.

Purpose of the Study:

• To develop a novel strategy for controlling IBV infection in chickens using genetic modification.
• To evaluate the efficacy of transgenic chickens expressing small interfering RNA (siRNA) against IBV.

Main Methods:

• Generation of transgenic chickens (G1) using a lentivirus vector to express siRNA targeting the IBV M protein.
• In vitro stimulation of monocytes from transgenic chickens with IBV.
• In vivo assessment of siRNA efficacy in terms of viral replication, mortality, weight gain, and inflammatory/oxidative responses.

Main Results:

• siRNA expression in monocytes significantly inhibited IBV replication in vitro.
• Transgenic chickens exhibited reduced levels of inflammatory cytokines, Mx protein, and nitric oxide during early IBV infection.
• In vivo, siRNA expression led to decreased IBV replication, significantly lower mortality rates, and improved weight gain.
• Reduced inflammatory responses and oxidative damage resulted in minimal tissue injury in transgenic birds.

Conclusions:

• Expression of siRNA targeting the IBV M protein is a viable strategy to inhibit viral replication and associated inflammatory responses in chickens.
• This genetic approach offers a promising method for enhancing disease resistance and improving poultry health against IBV.
• The study highlights the effectiveness of siRNA in controlling viral infections and reducing disease impact in avian populations.