HIV-1 Nef generates lasting innate immune memory in haematopoietic stem and progenitor cells in vivo.

HIV infection is accompanied by chronic inflammation-related co-morbidities, even when viral replication is suppressed by therapy. This persistent inflammatory state suggests that long-lived immune cell lineages may acquire stable pro-inflammatory programming. Here, we investigate whether inflammatory programming can be imprinted within hematopoietic lineages, following the exposure of mice and bone marrow-derived macrophages (BMDMs) to extracellular vesicles (EVs) carrying Nef, a key inflammatory factor of HIV. Multi-omics profiling shows that hematopoietic cells exposed to Nef-EVs undergo epigenetic remodeling and reprogramming of energy and lipid metabolism characteristic of trained innate immunity. The inflammatory phenotype in BMDMs is partially reversed by inhibition of glycolysis, a key metabolic driver of trained immunity. We demonstrate that following competitive bone marrow transplantation, hematopoiesis in mice receiving bone marrow from Nef-EV-treated donors displays a sustained bias toward myelopoiesis, and BMDMs retain enhanced inflammatory potential. These findings demonstrate that Nef-EVs can imprint a lasting inflammatory memory, mechanistically similar to trained immunity, in hematopoietic cells. This memory persists beyond the initial exposure and may contribute to chronic inflammation in people with HIV.