Interaction between envelope protein of Jaagsiekte Sheep Retrovirus and Hippo signaling pathway is inferred from transcriptome analysis of naturally infected Ovine Pulmonary Adenomatosis

Background Ovine pulmonary adenomatosis (OPA) is a contagious lung epithelial tumor of sheep caused by jaagsiekte sheep retrovirus (JSRV), which causes severe economic losses for the sheep industry in the world. The specific oncogenic mechanism of JSRV is not yet clarified. Methods In this study, RNA was extracted from lung tissues of 3 naturally infected OPA cases and 3 healthy individuals for transcriptome sequencing (RNA-Seq). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to confirm the sequencing data. Immunohistochemistry (IHC) and western blot (WB) were performed to confirm the signaling pathway enriched by DEGs that was activated in naturally infected OPA cases. Cell viability, wound-healing, transwell and colony formation assays were performed to assess the cell malignant transformation of sheep trophoblast cells (STCs) transformed with JSRV- env lentivirus in vitro, and then WB was performed to confirm the signaling pathway that had been validated in the lung tissues. Results A total of 366 DEGs (154 up-regulated and 212 down-regulated) were identified by RNA-Seq of lung tissues of naturally infected OPA cases and healthy individuals. GO analysis showed that 366 DEGs were significantly enriched in 178 GO terms, including 114 biological processes, 19 cellular components and 45 molecular functions. KEGG analysis showed that the DEGs mainly enriched in cell proliferation, differentiation, apoptosis and migration, such as PI3K/Akt/mTOR, MAPK and Hippo signaling pathway, and Hippo signaling pathway has never been reported in naturally infected OPA cases. qRT-PCR results of 10 DEGs which were selected randomly were consistent with RNA-Seq results. The protein expression of Hippo signaling pathway were up-regulated in naturally infected OPA lung tissues. Cell viability, wound-healing, transwell and colony formation assays confirmed that JSRV- env lentivirus caused malignant transformation of STCs and JSRV Env increased the protein expression of Hippo signaling pathway. Conclusions This research first identified the changes in the transcriptome level of naturally infected OPA lung tissues. These data confirm that the Hippo signaling pathway is involved in the mechanism of OPA, clarify the interaction between Hippo signaling pathway and JSRV Env, provide further evidence for the tumorigenic mechanism of JSRV.

The Diagnostic Challenges of Ovine Pulmonary Adenocarcinoma

Ovine pulmonary adenocarcinoma (OPA), also known as sheep pulmonary adenomatosis and jaagsiekte, is a contagious pulmonary tumor of sheep, characterized by neoplastic proliferation of type II pneumocyte and club cells. OPA is induced by the oncogenic activity of the envelope glycoprotein (Env) of exogenous jaagsiekte sheep retrovirus (JSRV). This disease is associated with significant economic losses in numerous sheep raising countries. The onset of suggestive clinical signs is often late, making difficult the early diagnosis of the disease and timely implementation of control measures on the affected farms. Further, the lack of diagnostic tests that can be performed routinely by veterinary clinicians to accurately assess infected animals (e.g., serological or others) means that the true prevalence at flock level is not known. Imaging diagnostic methods (e.g., ultrasound, X-ray and computed tomography) can be used to support the clinical diagnosis, even in pre-clinical stages in affected flocks. The diagnosis must be confirmed by PCR of nasal excretions or immunohistochemistry and PCR of tumor lesions. No vaccine for OPA has yet been developed. Thus, in this work, we review the main methods of diagnosis of OPA in order to support the clinician in the identification of the disease, avoid underdiagnosis and allow the implementation of suitable measures to prevent and control its spread.

Selected tumour biomarker levels in sheep with pulmonary adenomatosis

IntroductionSheep pulmonary adenomatosis (ovine pulmonary adenomatosis, OPA, Jaagsiekte) is a chronic contagious bronchoalveolar carcinoma caused by the Jaagsiekte sheep retrovirus. Since effective treatment and a vaccination procedure are not currently possible, control and eradication of the disease is difficult. It leads to serious economic losses around the world, therefore studies are currently underway in order to design control and eradication programmes. In this study, levels and changes in selected tumour markers (carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 125, CA 19-9, CA 15-3, and alphafetoprotein (AFP)-3) and their diagnostic significance were investigated.Material and MethodsA total of 30 sheep were used. Clinical examinations were performed and blood samples were obtained before slaughter from all animals with presumed OPA. Blood samples with positive OPA results by macroscopic and histopathological examination were included in the study as the experimental group and numbered 20. Sheep totalling 10 had negative OPA results and provided control samples.ResultsCEA levels were similar in both groups, and the differences were statistically insignificant (P > 0.05). CA 125, CA 19-9, CA 15-3, and AFP-3 levels were higher in the OPA group than the control group and with statistical significance (P < 0.05). In all OPA animals, CA 125 levels were higher than 1 U/mL.Conclusionserum CAs and AFP levels increase significantly in adenomatous sheep. These tumour markers are thought to facilitate the diagnosis of OPA.

Prevalence of Pneumonia in Sheep and Goats Slaughtered at Elfora Bishoftu Export Abattoir, Ethiopia: A Pathological Investigation

Accurate clinical diagnosis of pneumonia, the leading cause of mortality in small ruminants, is difficult and usually requires postmortem examination of the lungs. An active abattoir survey was conducted between November 2017 and April 2018 to estimate the prevalence and characterize the gross and histopathological lesions of pneumonic lungs in 864 clinically healthy young small ruminants (490 sheep and 374 goats aged 1.5 to 3 years) raised for meat in different parts of the country and slaughtered at Elfora Bishoftu export abattoir, Ethiopia. Out of the total lungs examined grossly, pneumonic lesions were found in 158 (18.29%) lungs. On histopathological examination of the lungs with gross pneumonic lesion, however, typical pneumonic lesions were diagnosed in 148 (17.13%) lungs only. No significant (p>0.05) difference was noted in the prevalence of pneumonia between sheep (17.14%) and goats (17.11%) in histopathological examination. Based on the predominant histopathological findings, the pneumonic lesions were characterized as interstitial pneumonia (41.9%), acute suppurative bronchopneumonia (25.7%), acute fibrinous bronchopneumonia (24.3%), chronic bronchopneumonia (6.1%), aspiration pneumonia (4.7%), bronchointerstitial pneumonia (3.4%), and ovine pulmonary adenomatosis (3.4%). The study further showed the spread of ovine pulmonary adenomatosis and ovine progressive pneumonia (Maedi) from the central highlands to areas that were previously free from these diseases. Due to its better diagnostic capacity, histopathology should be employed routinely as an ancillary test in the major abattoirs and regional veterinary laboratories to generate additional epidemiological data for a better disease control and prevention measures. Further studies are also recommended to identify the etiological agents of pneumonia in sheep and goats and thereby to formulate feasible and cost-effective interventions.

SLOW VIRAL INFECTIONS OF SMALL RUMINANTS IN GREECE

The slow viral infections are from the most important problems of sheep and goatproduction in Greece. Diseases as enzootic nasal tumor, Maedi-Visna, caprinearthritis-encephalitis, pulmonary adenomatosis and Scrapie can cause significantlosses in sheep and goat flocks. They can be transmitted during grazing or with animalsales. Here are described the clinicopathological findings of the aforementioneddiseases, as well as their diagnosis and control.

Análisis de la prevalencia de adenomatosis pulmonar en ovinos de la Sierra Central del Perú, Mayo 2017 (Analysis of the prevalence of pulmonary adenomatosis in sheep of the central highlands of Perú, May 2017)

El presente trabajo se realizó en la SAIS Túpac Amaru, localizada en -11.76° latitud sur y longitud -75.73°, sierra central del Perú. La altitud fluctúa entre 3600 a 4800 msnm, con temperaturas que oscilan entre -5°C a 18°C. El objetivo del estudio, fue analizar la prevalencia de la adenomatosis pulmonar ovina, para lo cual se consideró como población a 74,179 ovinos de la raza Junín. El método utilizado fue el análisis de los registros de mortalidad de ovinos en los últimos cuatro años, considerando, clases de ganado, edad y sexo. Se concluye que la enfermedad ha ocasionado una mortalidad de 4,670 ovinos durante el período de cuatro años, es decir el 1.45% de la población en promedio.Los animales adultos, son la mayoría de los casos muertos, existiendo también mortalidad en animales jóvenes, en machos con mayor frecuencia que en hembras. En cuanto a la media de la tasa de prevalencia puntual, se determinó un 1.5 % anual a nivel de la SAIS Túpac Amaru. Habiéndose encontrado la mayor tasa en capones 9.6%, seguido por carneros 4.5 % y borregas 2.2 %; aunque se observó también en animales jóvenes como: corderos 0.1%, borreguillas 0.4 %, carnerillos 1.3 % y caponcillos 1.6 %; lo cual indica que la enfermedad es prevalente en todas las edades y clases.La tasa de prevalencia acumulada va en incremento: 5.8 % (IC 0.05 a 0.06) a nivel de SAIS en cuatro años considerados en el presente estudio. Siendo más preocupante el caso de corderos que también va en incremento 0.6 %. Este hecho constituye un gran problema sanitario muy grave en la explotación ganadera por cuanto merma la producción y afecta directamente la rentabilidad de la empresa, y requiere ser abordada muy seriamente a nivel de política ganadera por parte del estado y todas las universidades.