The innate immune response in Salmo salar, mediated by pattern recognition receptors (PRRs), is crucial for defending against pathogens. This study examined DDX41 protein functions as a cytosolic/nuclear sensor for cyclic dinucleotides, RNA, and DNA from invasive intracellular bacteria. The investigation determined the existence, conservation, and functional expression of the ddx41 gene in S. salar. In silico predictions and experimental validations identified a single ddx41 gene on chromosome 5 in S. salar, showing 83.92% homology with its human counterpart. Transcriptomic analysis in salmon head kidney confirmed gene transcriptional integrity. Proteomic identification through mass spectrometry characterized three unique peptides with 99.99% statistical confidence. Phylogenetic analysis demonstrated significant evolutionary conservation across species. Functional gene expression analysis in SHK-1 cells infected by Piscirickettsia salmonis and Renibacterium salmoninarum indicated significant upregulation of DDX41, correlated with increased proinflammatory cytokine levels and activation of irf3 and interferon signaling pathways. In vivo studies corroborated DDX41 activation in immune responses, particularly when S. salar was challenged with P. salmonis, underscoring its potential in enhancing disease resistance. This is the first study to identify the DDX41 pathway as a key component in S. salar innate immune response to invading pathogens, establishing a basis for future research in salmonid disease resistance.

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. During the last few years, remarkable advances have been made in the treatment of DN. Sodium–glucose cotransporter type 2 inhibitors (SGLT2i) consistently prevent or delay albuminuria and renal failure in patients with DN. Prior research from our group highlights the Janus kinase/signal transducers and activators of transcription axis as a critical target in DN. Specifically, the administration of suppression of cytokine signaling 1 (SOCS1) mimetic peptides (MiS1) modulates aberrant signaling, resulting in profound beneficial effects on renal function and structural integrity in experimental DN. The aim of this study was to evaluate the effect of empagliflozin and MiS1 on kidney damage and its associated inflammatory, oxidative stress and lipotoxic mechanisms in an advanced type 2 DN mouse model BTBR ob/ob. Mice were treated for 7 weeks with empagliflozin and MiS1, alone or in combination, and monitored for glycemia, body weight, albuminuria, histopathological damage, podocyte loss, and gene expression related to inflammation, redox balance, and lipid metabolism. Empagliflozin or MiS1 monotherapies significantly reduced albuminuria and structural renal injury, preserved podocyte number, and downregulated genes involved in inflammatory, oxidative, and mitochondrial–lipid metabolic dysregulation, with empagliflozin additionally improving metabolic parameters. Notably, the combined therapy achieved the greatest reduction in albuminuria and histological damage with enhanced suppression of pathogenic inflammatory and metabolic pathways, resulting in superior renoprotection compared with monotherapy. These findings suggested that add-on therapy with SOCS1 peptidomimetics and SGLT2i may help mitigate residual albuminuria and renal damage in type 2 DN.

Renibacterium salmoninarum, the etiological agent of bacterial kidney disease, is a facultative intracellular pathogen whose interaction with salmonid phagocytic cells remains poorly resolved at the protein level. Here, we aimed to define the temporal protein-abundance architecture of SHK-1 macrophage-like cells after R. salmoninarum inoculation and to test whether this response supports broad canonical cell-death pathway engagement. We used label-free quantitative LC-MS/MS proteomics to profile SHK-1 cells over a 48 h post-inoculation time course. Because the design included a single non-infected T0 baseline, analyses were framed as baseline-referenced post-inoculation comparisons rather than a fully controlled mock time course. Of 6842 proteins retained for statistical modeling, 2254 were strictly differentially abundant in at least one contrast relative to T0 (adjusted p < 0.05 and |log₂FC| ≥ 0.585). Perturbation was strongest at 1–2 h and progressively contracted at later time points. Among 1278 recurrent proteins, k-means clustering resolved four temporal modules capturing coordinated remodeling of lysosomal, immunometabolic, cytoskeletal, stress-response, and antioxidant programs. A curated cell-death panel spanning apoptosis, pyroptosis, necroptosis, ferroptosis, and PANoptosis yielded only three detected markers; CASP3 and MLKL met the strict threshold, whereas ACSL4 remained sub-threshold. Overall, early host-cell remodeling, rather than broad canonical death-program execution, was the predominant proteomic signature of SHK-1 cells during the first 48 h after R. salmoninarum inoculation.