Targeting Nuclear Lipid Droplets: Expanding Host-Directed Antiviral Therapies for Emerging Viral Threats

The increasing emergence of viral threats underscores the urgent need for broad-spectrum antiviral therapies that are resilient to viral mutation. Traditional direct-acting antivirals (DAAs) targeting virus-specific proteins face limitations in adaptability and durability. Host-directed strategic targets (HDSTs), which modulate host pathways essential for viral replication and immune response, represent a promising alternative. Lipid droplets (LDs) have been shown to play pivotal roles in viral replication, assembly, and immune modulation. Pharmacological or genetic disruption of LD biogenesis has demonstrated antiviral effects against multiple RNA viruses, including HCV, flaviviruses, and SARS-CoV-2. This paper explores the largely uncharacterized role of nuclear lipid droplets (nLDs) in host-virus interactions. Unlike cytoplasmic lipid droplets (cLDs), nLDs reside in the nucleus and are associated with nuclear membrane remodeling, stress responses, and intrinsic immunity. Although their exact contribution to viral replication or defense is unknown, their presence in contexts of ER stress, aging, and steatosis and association with promyelocytic leukemia (PML) nuclear bodies suggests they may play a role in regulating nuclear lipid availability and antiviral signaling. nLDs may either restrict nuclear-replicating viruses by concentrating antiviral proteins or support them by supplying lipids for nuclear envelope modification. The distinct molecular composition of nLDs, including enrichment of perilipin-3 and promyelocytic leukemia protein, allows for the potential development of nLD-specific interventions. Targeted manipulation of these components may destabilize nLDs and alter the course of infection. Furthermore, host genetic variation in lipid-handling genes such as PCSK9 may significantly influence lipid droplet dynamics and, consequently, antiviral treatment efficacy. Genetic polymorphisms that confer resistance or susceptibility could serve as biomarkers to guide personalized HDST approaches. Highlighting the differential roles of cLDs and nLDs in infection and integrating host genetic variability may inform a more refined and adaptable antiviral strategy. Targeting nLDs may enhance the effectiveness of HDSTs while minimizing host metabolic disruption. This approach holds promise for advancing antiviral therapy design, improving pandemic preparedness, and informing global strategies for equitable and scalable therapeutic deployment. This paper explores the largely uncharacterized role of nuclear lipid droplets (nLDs) in host-virus interactions. Unlike cytoplasmic lipid droplets (cLDs), nLDs reside in the nucleus and are associated with nuclear membrane remodeling, stress responses, and intrinsic immunity. Although their exact contribution to viral replication or defense is unknown, their presence in contexts of ER stress, aging, and steatosis and association with promyelocytic leukemia (PML) nuclear bodies suggests they may play a role in regulating nuclear lipid availability and antiviral signaling. nLDs may either restrict nuclear-replicating viruses by concentrating antiviral proteins or support them by supplying lipids for nuclear envelope modification. The distinct molecular composition of nLDs, including enrichment of perilipin-3 and promyelocytic leukemia protein, allows for the potential development of nLD-specific interventions. Targeted manipulation of these components may destabilize nLDs and alter the course of infection. Furthermore, host genetic variation in lipid-handling genes such as PCSK9 may significantly influence lipid droplet dynamics and, consequently, antiviral treatment efficacy. Genetic polymorphisms that confer resistance or susceptibility could serve as biomarkers to guide personalized HDST approaches. Highlighting the differential roles of cLDs and nLDs in infection and integrating host genetic variability may inform a more refined and adaptable antiviral strategy. Targeting nLDs may enhance the effectiveness of HDSTs while minimizing host metabolic disruption. This approach holds promise for advancing antiviral therapy design, improving pandemic preparedness, and informing global strategies for equitable and scalable therapeutic deployment.