Distribution of importin-α isoforms in poultry species and their tissue- and age-related differences.

While importin-α is well studied in mammals, the knowledge in avian species is still limited. In this study, we compared the mRNA expression patterns of five importin-α isoforms in the respiratory tract, liver, and spleen of chickens, turkeys, and pekin ducks in two different age-groups. In addition, we determined the distribution of importin-α in selected tissue of conchae, trachea, and lung of post-hatch chickens at all cellular levels by immunohistochemical staining. Our results indicate that importin-α3 is the most abundant isoform in the respiratory tract of chickens, turkeys, and pekin ducks. Moreover, importin-α is expressed as a gradient with lowest mRNA levels in the conchae and highest levels in the lung. The mRNA expression levels of most isoforms were higher in tissues from post-hatch chickens and turkeys in comparison to the corresponding embryos. In contrast to that, duck embryos mostly show higher mRNA expression levels of importin-α than post-hatch ducks.

In Vitro Investigation of the Interaction of Avian Metapneumovirus and Newcastle Disease Virus with Turkey Respiratory and Reproductive Tissue.

In poultry, several respiratory viral infections lead to a drop in egg production associated with high economic losses. While the virus-host interactions at the respiratory epithelium are well studied, less is known about these interactions in the oviduct. To investigate possible differences between virus infections at these epithelial structures, we compared the interactions of two important poultry viruses on turkey organ cultures. Two members of the order Mononegavirales, the Avian Metapneumovirus (AMPV) and the Newcastle disease virus (NDV), were selected to conduct the in vitro experiments since these viruses can infect both the trachea and oviduct. In addition, we used different strains of these viruses, a subtype A and a subtype B strain for AMPV and the NDV strains Komarow and Herts'33, to detect possible differences not only between the tissues but also between different viral strains. Turkey tracheal and oviduct organ cultures (TOC and OOC) were prepared to investigate viral replication, antigen localisation, lesion development, and the expression pattern of interferon-λ and importin-α isoforms. All viruses replicated more efficiently in the oviduct than in the tracheal epithelium (p < 0.05). In addition, we observed higher expression levels of both, IFN-λ and importin-α in OOCs compared to TOCs. Our results indicated strain-dependent differences, with the AMPV-B- and Herts'33 strains being more virulent in organ cultures than the AMPV-A- and Komarow strains, based on the higher viral genome loads, more severe histological lesions, and higher upregulation of IFN-λ. Overall, our findings reveal tissue- and virus strain-dependent differences, which may have consequences for disease development in the host tissue and, subsequently, possible treatment strategies.