HIV-1 infection in microglia induces HIV-associated neurocognitive disorder (HAND). Recent evidence suggests that microglia can be infected with HIV-1 in the active, persistent, or latent replication stages. The molecular mechanisms governing these stages of infection are still the subject of continuous study. In this study, we analyzed the relationship between HIV-1 infection and two lncRNAs, NEAT1 and ZBTB11-AS1, on different days post-infection. We found that on days 1 and 4 post-infection, HIV-1 was actively replicating; meanwhile, by day 21, HIV-1 had entered a persistent stage. We also noted that the expression levels of NEAT1 and ZBTB11-AS1 varied during these different stages of HIV-1 infection in microglia, as did their subcellular localization. We performed an interaction network analysis and identified DDX3X and ZC3HAV1 as hypothetically related to NEAT1 and ZBTB11-AS1 in the C20 human microglial cell line. Additionally, we determined that IL-6, a cytokine regulated by DDX3X and ZC3HAV1, exhibits changes in protein expression levels during both active and persistent HIV-1 infection.

Salmonid rickettsial septicemia (SRS), caused by Piscirickettsia salmonis, has been the most severe health concern for the Chilean salmon industry. The efforts to control P. salmonis infections have focused on using antibiotics and vaccines. However, infected salmonids exhibit limited responses to the treatments. Here, we developed a poly (D, L-lactide-glycolic acid) (PLGA)-nanosystem functionalized with Atlantic salmon IgM (PLGA-IgM) to specifically deliver florfenicol into infected cells. Polymeric nanoparticles (NPs) were prepared via the double emulsion solvent-evaporation method in the presence of florfenicol. Later, the PLGA-NPs were functionalized with Atlantic salmon IgM through carbodiimide chemistry. The nanosystem showed an average size of ~380–410 nm and a negative surface charge. Further, florfenicol encapsulation efficiency was close to 10%. We evaluated the internalization of the nanosystem and its impact on bacterial load in SHK-1 cells by using confocal microscopy and qPCR. The results suggest that stimulation with the nanosystem elicits a decrease in the bacterial load of P. salmonis when it infects Atlantic salmon macrophages. Overall, the IgM-functionalized PLGA-based nanosystem represents an alternative to the administration of antibiotics in salmon farming, complementing the delivery of antibiotics with the stimulation of the immune response of infected macrophages.

Andrographolide, fucoidan, or a combination of both compounds were evaluated to determine their effects on the antiviral response in the Atlantic salmon macrophage-like cell line (SHK-1) infected with infectious pancreatic necrosis virus (IPNV). We assessed the transcript expression levels of key molecules involved in the interferon (IFN)-dependent antiviral response, as well as the viral load in cells treated with these compounds. In non-infected cells, incubation with either fucoidan, andrographolide, or a mixture of both resulted in an increase in the transcript expression of IFNα1 and various interferon-stimulated genes (ISGs). In IPNV-infected cells, treatment with either fucoidan or andrographolide separately did not significantly enhance the antiviral response compared to that of infected cells that had not previously been treated with these compounds. In contrast, the combination of andrographolide and fucoidan led to a marked increase in the transcript expression of viperin and a significant reduction in viral load. Overall, combining andrographolide and fucoidan resulted in a greater reduction in IPNV viral load in infected cells than that noted when the compounds were administered individually. Our findings suggest that pre-incubation with this mixture promotes the establishment of a protective antiviral state against IPNV, likely mediated by an IFN-dependent response.

Microglia, the resident macrophages of the central nervous system (CNS), serve as the primary reservoir of HIV-1 in the brain and play a crucial role in the development of HIV-1-associated neurocognitive disorders (HAND). While long non-coding RNAs (lncRNAs) have emerged as essential regulators of HIV-1 replication in T cells and macrophages, their role in microglia remains poorly understood. Here, we performed RNA sequencing of polyadenylated transcripts from a human microglial cell line exposed to HIV-1 infection or TNF-α stimulation to investigate transcriptional responses and identify lncRNAs with potential regulatory functions. Gene set enrichment analysis revealed broad overlap between viral and inflammatory responses, reflecting convergence on common molecular pathways. Among differentially expressed lncRNAs, we focused on TALAM1, which was specifically induced by HIV-1, and LINC00702, which responded to both HIV-1 and TNF-α. Validation by RT-qPCR confirmed the upregulation of TALAM1 and LINC00702 at 24 h post-infection. Furthermore, knockdown of either lncRNA affected viral genomic RNA levels, while only LINC00702 knockdown affected p55 production. Given that subcellular localization informs lncRNA function, we assessed the distribution of TALAM1 and LINC00702. TALAM1 was predominantly cytoplasmic under basal conditions but shifted toward nuclear enrichment upon HIV-1 infection, whereas LINC00702 remained primarily nuclear regardless of infection status. Consistent with their genomic context, protein interaction predictions, and pathway enrichment analyses suggested that TALAM1 may influence RNA processing and splicing, whereas LINC00702 may contribute to translational regulation and is associated with proteins involved in immune responses. Together, these findings provide an initial characterization of lncRNA responses to HIV-1 infection in a human microglial cell line and identify TALAM1 and LINC00702 as candidates for future functional studies in the context of viral infection and neuroinflammation.