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TIR8/SIGIRR is expressed in tissues of adult and embryo chicken
No full textThe orphan receptor TIR8/SIGIRR, belongs to the TIR superfamily. TIR8 does not activate NF-kB and IRF3 and negatively modulates the inflammatory responses. It acts as antagonist for the TIR family members and triggers a negative pathway of the TIR receptor system, crucial for dampening inflammation. TIR8 was well characterized in mouse, humans and in other mammals, but it is poorly known in birds.
We investigated TIR8 distribution in adult and embryo chicken samples. The pattern of expression of chicken TIR8 in adult was ubiquitary and similar to mammals, but it resulted unique in pancreas, female reproductive tract, heterophils. Different TIR8 isoforms were detected, suggesting the occurrence of post-translational modifications or alternative splicing. Immunohistochemistry revealed TIR8 immunolabeling in the intestine, thymus and oesophageal ganglia. These results demonstrate that TIR8, although evolutionarily conserved, show species-specific peculiarities. We analyzed TIR8 expression in embryos of layer- and broiler-chicken at different incubation time-points. TIR8 was detected since the first stages of development, but it reached a remarkable expression level at day 10. TIR8 was ubiquitously expressed, but the highest expression were found in liver and kidney. This pattern was comparable to those observed in adult chickens and in mammals examined to date. No differences were observed between the two different chicken breeds despite their immunological discrepancies. These are the first findings concerning TIR8 expression in developmental stages and they contribute to better understand the reproductive physiology and transovarian pathogen transmission, together with the recent findings of TLR expression in ovary and embryos of different species
Expression of TIR8 receptor in chicken tissues
No full textThe orphan receptor TIR8, also known as SIGIRR, belongs to the TLR/IL-1R (TIR) superfamily and plays an important role in the immune response. The signalling pathways of the receptors belonging to the TIR family are tightly regulated at multiple levels and through different mechanisms. TIR8 negatively modulates innate immunity and inflammatory responses in the areas where it is primarily expressed (gastrointestinal tract, kidney and lung). TIR8 has been well characterized in mouse, humans and in other Mammalian species, but it is still poorly known in chicken. Given the importance of gastrointestinal diseases in chicken, the aim of our study was to investigate the distribution of TIR8 in a wide panel of non-pathologic tissues and organs. TIR8 expression was analyzed in chicken samples at both levels of transcript mRNA and translated protein. The pattern of expression of TIR8 (ubiquitous) was similar to Mammals for some tissues (high levels in kidney and gastrointestinal tract), but it resulted unique for other tissues. High expression was detected in liver, pancreas and female reproductive tract. Interestingly, the receptor was highly expressed also in heterophils, the most common granulocytes of birds. Few isoforms of chicken TIR8 were detected by Western blot, suggesting the occurrence of different post-translational processing in different organs. Immunohistochemistry revealed TIR8 immunolabelling in chicken intestine and thymus. These results demonstrate that the receptor, although evolutionarily conserved, show species-specific peculiarities
TIR8 expression in tissues of adult and embryo chicken
No full textThe orphan receptor TIR8/SIGIRR, belongs to the TIR superfamily and plays an important role in the inflammatory responses. TIR8 does not activate NF-kB and IRF3 and negatively modulates the inflammatory responses. It acts as antagonist for the TIR family members and triggers a negative pathway of the TIR receptor system, crucial for dampening inflammation in the gastrointestinal tract (GI) and in other districts. TIR8 was well characterized in mouse, humans and in other mammals, but it is poorly known in birds. We investigated TIR8 distribution in adult and embryo chicken samples at both mRNA and protein levels. The pattern
of expression of chicken TIR8 in adult was ubiquitary and similar to mammals (high levels in kidney and GI), but it
resulted unique in other tissues (pancreas, female reproductive tract, heterophils). Different protein isoforms of TIR8 were detected, suggesting the occurrence of different post-translational modifications or alternative splicing.
Immunohistochemistry revealed TIR8 immunolabeling in the intestine, thymus and oesophageal ganglia. These results
demonstrate that TIR8, although evolutionarily conserved, show species-specific peculiarities. We also analyzed TIR8 expression in embryos of two chicken breeds (layer- and broiler-type) at different time-points of incubation. TIR8 was detected since the first stages of chicken development (day 1), but it reached a remarkable expression level at day 10.
This receptor was ubiquitously expressed, but the highest expression levels were found in liver and kidney. This pattern was comparable to those observed in adult chickens and in mammals examined to date. No expression
differences were observed between the two different chicken breeds despite their marked immunological
discrepancies. These are the first findings concerning TIR8 expression in developmental stages and they contribute to better understand the reproductive physiology and transovarian pathogen transmission, together with the recent findings of TLR expression in ovary and embryos of different species
SET-UP AND APPLICATION OF BIOTECHNOLOGICAL METHODS IN AVIAN FIELD
Full text linkThe use of biotechnology in avian field has been increased in the last decade especially on the track of the complete sequencing of chicken genome and on the global threat of avian flu pandemic which alerted the scientific community worldwide. Nevertheless, it is still on the whole a minor and spotty approach in avian field. Matter-of-factly, birds can be roughly divided into two groups on a research point of view: poultry and non-poultry (companion and wild birds). The economic impact of the latter is usually scarce if compared to the former and to other veterinary and human contexts. Thus, routine use of laboratory diagnostic tools including biotechnological methods is usually limited to the more expensive psittacines species (i.e. DNA-based determination of sex, diagnosis of chlamydiosis etc.) or to endangered species. As for poultry, extensive use of biotechnology is performed in vaccine research and genetic selection with a secondary role in avian and comparative pathology. Besides, chicken has historically assumed the role of avian model. Consequently, birds are often considered an uniform class but they are not, and a deep knowledge of the huge diversity which can exist among the several avian species is fundamental to correctly approach and interpret avian research no matter using biotechnology or not. For all these reasons it seemed an unique occasion to match the documented experience and activity in avian field (acquired during a previous doctorate) to biotechnological methods as the subject of this doctoral thesis.
After a brief introduction revising fundamental principles of the molecular methods used, this thesis is divided into two parts. The first is focused on avian immunity and in particular on the TIR8-SIGIRR receptor which has been thoroughly investigate in chickens as a model for avian species and with an importance in itself as an ubiquitously diffused food production animal. The second part is made up of some diagnostic challenges arisen during the routine diagnostic activity of the Section of Avian Pathology of the Department of Veterinary Science and Public Health
Histological and histochemical investigations on hepatic lipidosis in turkeys
No full textThis study describes peculiar cases of hepatic lipidosis in turkeys and the results of histochemical and immunohistochemical approaches aimed at better detailing this condition. Hepatic lipidosis of the turkey is a syndrome described in turkey and characterized by enlarged livers mottled by pale yellow areas. Histologically, the main feature is fatty degeneration associated with necrosis and haemorrhage. The cause of hepatic lipidosis is uncertain although nutritional and metabolic factors are suspected. Over a period of 6 years, we observed 8 cases of a hepatopathy with gross and microscopic changes consistent with hepatic lipidosis. Two of these cases affected turkey breeder hens of 12th and 21st week of age. Interestingly, another case was observed at slaughterhouse in 20-week old commercial male turkeys, whereas 5 cases involved commercial poults of 5 to 26 days. Histochemistry revealed the maintenance of the reticulin framework in hepatic lipidosis and excluded a disorder in copper metabolism. Positive adipophilin immunohistochemistry confirmed hepatic lipidosis is characterized by nonphosphorylated lipid accumulations within hepatocytes. Current and alternative pathogenetic hypotheses for hepatic lipidosis are discussed on the basis of these results
Hepatic lipidosis in turkeys : beyond the current pathogenetic hypothesis
No full textHepatic lipidosis (HL) is a condition described in young turkey hens and characterized by enlarged livers mottled by pale yellow areas. Histologically, the main feature is fatty degeneration associated with necrosis and haemorrhage. The cause of HL is uncertain although nutritional and metabolic factors are suspected. Over a period of 2 years, we observed 5 cases of a hepatopathy with gross and microscopic changes consistent with HL. Two of these cases affected turkey breeder hens of 12 and 21 weeks. Interestingly, another case was observed at sloughterhouse in 20 weeks commercial male turkeys, whereas 2 cases involved commercial poults of 8 and 26 days. An histochemical approach could better detail this condition and help speculating about its pathogenesis
Lesioni podali e benessere del broiler: osservazioni preliminari
No full textFoot pad dermatitis and welfare in broiler chickens. An attempt to classify broiler foot health status using the method developed in Sweden by Ekstrand et al. for the control of foot pad dermatitis was carried out. The Italian market demanded heavy broilers (3.5 kg and more) at 56 days of age. In this condition, the foot pad dermatitis was frequent as a consequence of feed composition, litter material, stocking density and climatic conditions. Foot pad dermatitis evaluation and classification of lesions at slaughterhouses were very difficult. Gross and histological lesions were not always comparabl
Morphological and immunohistochemical observations on Leiomyoma of the ventral ligament of the oviduct of the Hen
No full textLeiomyomas of the ventral ligament (LVLs) of the oviduct from 2-year-old spent layers were examined. These tumours can be present either as single large masses or as multiple smaller nodules. The most common site of origin of the tumours was the centre of the free margin of the ventral ligament, but some small tumours were observed at the insertion of this ligament into the magnum of the oviduct. Most samples were highly vascular and some blood vessels within the tumours had vacuolation of the smooth muscle cells. These findings suggest that the proliferative processes leading to LVLs may include transformation of the blood vessels of the ventral ligament. Immunohistochemically, the tumour cells expressed vimentin, α-smooth muscle actin, desmin and heavy-caldesmon. These avian leiomyomas have been proposed as a model for similar tumours in other species
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