Mutations in the Neuroligin-3 (Nlgn3) gene are implicated in autism spectrum disorder (ASD) and gastrointestinal (GI) dysfunction but cellular Nlgn3 expression in the enteric nervous system remains to be characterised. We combined RNAScope in situ hybridization for Nlgn3 mRNA and immunofluorescence for cholinergic and VIP-expressing submucosal neurons, nitrergic and calretinin-containing myenteric neurons and glial cells. We measured Nlgn3 mRNA neuronal and glial expression via quantitative 3-dimensional image analysis. To validate dual RNAScope/immunofluorescence data, we interrogated available single cell RNA sequencing (scRNASeq) data to assess for Nlgn3, Nlgn1, Nlgn2 and their binding partners, Nrxn1-3, MGDA1 and MGDA2, in enteric neural subsets. Most submucosal and myenteric neurons expressed Nlgn3 mRNA. In contrast to other Nlgns and binding partners, Nlgn3 was strongly expressed in enteric glia, suggesting a role for Neuroligin-3 in mediating enteric neuron-glia interactions. The autism-associated R451C mutation reduces Nlgn3 mRNA expression in cholinergic but not VIPergic submucosal neurons. In the myenteric plexus, Nlgn3 mRNA levels are reduced in calretinin and NOS labelled neurons and S100ß labelled glia. We provide a comprehensive cellular profile for neuroligin-3 expression in ileal neuronal subpopulations of mice expressing the R451C autism-associated mutation in Nlgn3, which may contribute to the understanding of the pathophysiology of GI dysfunction in ASD.

Immune checkpoints are a set of molecules dysregulated in several human and canine cancers and aberrations of the PD-1/PD-L1 axis are often correlated with a worse prognosis. To gain insight into the role of immune checkpoints in canine diffuse large B-cell lymphoma (cDLBCL), we investigated PD-L1, PD-1 and CD8A expression by RNAscope. Results were correlated with several clinico-pathological features, including treatment, Ki67 index and outcome. A total of 33 dogs treated with CHOP (n=12) or CHOP plus APAVAC (n= 21) were included. PD-L1 signal was diffusely distributed among neoplastic cells, whereas PD-1 and CD8A were localized in tumor infiltrating lymphocytes. However, PD-1 mRNA was also retrieved in tumor cells. An association between PD-L1 and PD-1 scores was identified and a higher risk of relapse and lymphoma-related death was found in dogs treated with chemotherapy alone and dogs with higher PD-L1 and PD-1 scores. The correlation between PD-L1 and PD-1 is in line with the mechanism of immune checkpoints in cancers, where neoplastic cells overexpress PD-L1 that, in turn, binds PD-1 receptors in activated TIL. We also found that Ki67 index was significantly increased in dogs with the highest PD-L1 and PD-1 scores, indirectly suggesting a role in promoting tumor proliferation. Finally, even if the biological consequence of PD-1+ tumor cells is unknown, our findings suggest that PD-1 intrinsic expression in cDLBCL might contribute to tumor growth escaping adaptive immunity.

Salmonid alphavirus strain 3 is responsible for outbreaks of pancreas disease in salmon and rainbow trout in Norway. Although the extensive amount of research on SAV3 focused mainly on the heart and pancreas (of clinical importance), tropism and pathogenesis studies of the virus in other salmon tissues are limited. Here, we used a combination of RT-qPCR (Q_nsp1 gene) and in situ hybridization (RNAscope®) to demonstrate the tropism of SAV3 in situ in tissues of Atlantic salmon, employing a challenge model (by cohabitation). In addition, as previous results suggested that pseudobranch may harbor the virus, the change in the expression of different immune genes upon SAV3 infection (RT-qPCR) was focused on the pseudobranch in the current study. In situ hybridization detected SAV3 in the heart, pseudobranch, gills, pyloric caeca, and pancreas after virus infection, with the heart ventricle showing the most extensive infection. Furthermore, the detection of the virus at different adipose tissues associated with the internal organs of the salmon, suggests a specific affinity of SAV3 to adipocyte’s components. The innate immune response to SAV3 in the pseudobranch after infection dominated over the adaptive responses, yet it did not mitigate the infection in that tissue. The early detection of SAV3 in the pseudobranch after infection, along with the persistent low infection over the experimental course, suggests a pivotal role of the pseudobranch in SAV3 pathogenesis in Atlantic salmon.