This research aimed to identify bioactive compounds from Caesalpinia sappan extract that function as novel porcine reproductive and respiratory syndrome virus (PRRSV) infection inhibitors by computational molecular screening. We obtained a set of small-molecule compounds predicted to target the scavenger receptor cysteine-rich domain 5 (SRCR5) of CD163. In addition, the functions of positive hits were assessed and verified utilizing an in vitro antiviral activity assay with PRRSV-infected MARC-145 cells. Combining molecular docking with the results of binding affinity and ligand conformation, it was found that brazilin had the highest binding energy with the SRCR5 receptor compared to catechin and epicatechin (− 5.8, − 5.5, and − 5.1 kcal/mol, respectively). In terms of molecular mechanics, the binding free energy between the SRCR5 receptor was − 15.71 kcal/mol based on the Poisson-Boltzmann surface area of brazilin. In addition, PRRSV infection in MARC-145 cells was significantly inhibited by brazilin compared to the control (virus titer, 4.10 vs. 9.25 TCID₅₀/mL, respectively). Moreover, brazilin successfully limited the number of PRRSV RNA copies in MARC-145 cells as determined by RT-qPCR. By inhibiting the PRRSV-CD163 interaction with brazilin from Caesalpinia sappan, it may be possible to prevent PRRSV infection in pigs, as suggested by this research.

Background: At present, porcine reproductive and respiratory syndrome (PRRS) caused by the PRRS virus (PRRSV) is one of the most severe epidemics impacting pig farming globally. Despite the fact that a number of studies have been conducted on potential solutions to this problem, none have proven effective. The focus of problem solving is the use of natural ingredients such as plant extracts. Popular throughout Asia, Caesalpinia sappan (CS) is a therapeutic plant that inhibits PRRSV in vitro. Therefore, this study was performed to determine the efficacy of CS extract dietary supplementation on the productive performance, antibody levels, immunological indicators, and lung pathology of PRRSV-challenged weaned pigs. A total of 32 weaned piglets (28 days old) were randomized into 4 groups and kept separately for 14 days. The treatments were organized in a 2 × 2 factorial design involving two factors: PRRSV challenge and supplementation with 1 mg/kg CS extract. The pigs in the PRRSV-challenged groups were intranasally inoculated with 2 mL of PRRSV (VR2332) containing 10⁴ TCID₅₀/mL, while those in the groups not challenged with PRRSV were inoculated with 2 mL of normal saline. Results: In the PRRSV-challenged group (CS + PRRSV), supplementation with CS extract led to an increase in white blood cells (WBCs) on Day 7 post infection (p < 0.05) and particularly in lymphocytes on Days 7 and 14. The antibody titer was significantly greater in the CS + PRRSV group than in the PRRSV-challenged group not administered CS (PRRSV group) on Day 14 postinfection (S/P = 1.19 vs. 0.78). In addition, CS extract administration decreased the prevalence of pulmonary lesions, which were more prevalent in the PRRSV-challenged pigs that did not receive the CS extract. Conclusion: The findings of this study suggest that supplementation with CS extract is beneficial for increasing WBC counts, especially lymphocytes, increasing the levels of antibodies and reducing the prevalence of lung lesions in PRRSV-infected pigs.

The current level of knowledge on transcriptome responses triggered by Caesalpinia sappan (CS) extract in porcine peripheral blood mononuclear cells (PBMCs) after porcine reproductive and respiratory syndrome virus (PRRSV) infection is limited. Therefore, in the present study, we aimed to detect significant genes and pathways involved in CS extract supplementation responsiveness of PBMCs after PRRSV infection. RNA sequencing was conducted on PBMCs, which were isolated from six weaned piglets. The resultant transcriptional responses were examined by mRNA sequencing. Differential expression analysis identified 263 and 274 differentially expressed genes (DEGs) between the PRRSV and CTRL groups, and the PRRSV+CS and CTRL groups, respectively. Among these, ZNF646 and KAT5 emerged as the most promising candidate genes, potentially influencing the interaction between PRRSV-infected PBMCs and CS extract supplementation through the regulation of gene networks and cellular homeostasis during stress. Two pathways were detected to be associated with CS extract supplementation responsiveness: the cellular response to stress pathway and the NF-kB signaling pathway. Consequently, our study reveals a novel mechanism underlying cellular stress response and the NF-κB signaling pathway in PRRSV-infected PBMCs, and identifies a potential application of CS extract for activating the NF-κB signaling pathway. In conclusion, by supplementing CS extract in PBMC cells infected with PRRSV, we found that CS extract modulates PRRSV infection by inducing cellular stress, which is regulated by the NF-κB signaling pathway. This induced stress creates an adverse environment for PRRSV survival. This study contributes to a deeper understanding of the therapeutic targets and pathogenesis of PRRSV infection. Importantly, our results demonstrate that CS extract has the potential to be a candidate for modulating PRRSV infection.

Canine hepatoid gland neoplasms (HGNs) are significant clinical concerns due to their high prevalence and diverse biological behaviour. Human epidermal growth factor receptor 2 (HER2), a tyrosine kinase receptor implicated in various aspects of tumorigenesis, has been extensively studied in human and animal neoplasms but remains unexplored in HGNs. This study aimed to assess HER2 immunoexpression in canine HGNs and its association with clinicopathological and morphological features. A total of 61 formalin-fixed paraffin-embedded samples, including normal hepatoid glands (n = 10), hepatoid gland adenomas (HGAs, n = 20), hepatoid gland epitheliomas (HGEs, n = 16), and hepatoid gland carcinomas (HGCs, n = 15), were analysed using immunohistochemistry. HER2 expression was scored based on percentage positivity and staining intensity. HER2-positive expression was detected in 50% of HGEs (score 2 + ) and 73.3% of HGCs, with 36.4% of cases scoring 3 + . In contrast, all HGAs and normal hepatoid tissues were HER2-immunonegative. Statistical analysis revealed significant differences in HER2 expression among normal and neoplastic hepatoid glands (p < 0.001). Only in HGCs, HER2 expression was significantly associated with tissue invasion (p = 0.007), mitotic count (p = 0.033), and nuclear pleomorphism (p = 0.007). These findings suggest that HER2 may play a role in the progression of malignant HGNs, particularly HGCs. This preliminary study highlights the potential of HER2 as a diagnostic marker and emphasizes the need for further investigation into its prognostic value and role in HER2-targeted therapy for canine HGCs.

Background and Aim: Liver injury results in the production of free radicals that can lead to hepatocytic degeneration, cirrhosis, and hepatocellular carcinoma (HCC). Liver-fatty acid-binding protein (L-FABP) is highly expressed in hepatocytes and is a key regulator of hepatic lipid metabolism and antioxidant characteristics. Interestingly, the increase in L-FABP expression could be used as a novel marker of liver injury. Therefore, this study aimed to use immunohistochemical techniques to investigate the expression of L-FABP in dogs with liver injury compared with dogs with non-pathological liver. Materials and Methods: Liver tissue samples were collected from dog biopsy specimens at the Veterinary Diagnostic Laboratory at the Faculty of Veterinary Medicine, Chiang Mai University. The tissues were prepared for immunohistochemistry and the expression and localization of L-FABP were investigated using one-way analysis of variance. Results: Immunohistochemical analysis showed that L-FABP was strongly expressed in the hepatocytes of dogs with lipidosis and HCC when compared with that in normal liver. Semi-quantitative immunohistochemistry evaluation showed the percentage of protein expression of L-FABP 0.023 ± 0.027 in the non-pathological liver. The percentage of L-FABP protein expression in lipidosis and HCC was found to be 8.517 ± 1.059 and 17.371 ± 4.026, respectively. Conclusion: L-FABP expression in dogs with liver injuries was significantly higher than that in dogs with non-pathological liver injury (p = 0.05). These results suggest that L-FABP has the potential as a novel marker for specific diagnosis and prognosis of dogs with liver injury. Keywords: canine, hepatocyte, immunohistochemistry, lipidosis, liver injury, liver-fatty acid-binding protein, pathology.