{"doi":"10.1128/mbio.00425-25","title":"SAMHD1 enhances HIV-1-induced apoptosis in monocytic cells via the mitochondrial pathway","abstract":"Sterile alpha motif (SAM) and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1) inhibits HIV-1 replication in non-dividing cells by reducing the intracellular dNTP pool. While SAMHD1 is known to promote spontaneous apoptosis, its role in HIV-1-induced apoptosis and the underlying mechanisms remain unclear. In this study, we identify a novel mechanism by which SAMHD1 enhances HIV-1-induced apoptosis in monocytic cells via the mitochondrial pathway. We demonstrate that SAMHD1 enhances apoptosis induced by HIV-1 infection in dividing monocytic THP-1 and U937 cell lines, but not in differentiated macrophage-like cells. Mechanistically, SAMHD1 expression reduces mitochondrial membrane potential and promotes cytochrome c release in HIV-1-infected THP-1 cells, thereby augmenting the mitochondrial apoptotic pathway. Furthermore, SAMHD1-enhanced apoptosis is linked to elevated levels of the pro-apoptotic protein BCL-2-interacting killer (BIK) in cells, which contributes to enhanced apoptosis during HIV-1 infection. These findings reveal a previously unrecognized regulatory role of SAMHD1 in amplifying HIV-1-induced apoptosis in monocytic cells, highlighting its involvement in the mitochondrial apoptotic pathway.IMPORTANCESterile alpha motif (SAM) and histidine-aspartate (HD) domain-containing protein 1 (SAMHD1), a dNTP triphosphohydrolase, lowers intracellular dNTP levels and restricts HIV-1 replication in non-dividing cells. HIV-1 infection induces cell death mainly through apoptosis. While we have shown that endogenous SAMHD1 enhances spontaneous apoptosis in monocytic cells, its role in HIV-1-induced apoptosis and the underlying mechanisms remain unknown. In this study, we aim to bridge this knowledge gap by investigating the functional significance of SAMHD1 in regulating apoptosis during HIV-1 infection of immune cells. Our findings reveal a novel mechanism whereby SAMHD1 enhances HIV-1-induced apoptosis in monocytic cells through the mitochondrial pathway. This suggests a previously unrecognized role of SAMHD1 in modulating cellular responses to HIV-1 infection.","journal":"mBio","year":2025,"id":519623,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":6,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.961,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1388011,"name":"Pak‐Hin Hinson Cheung","orcid":"0000-0003-3682-7571","position":1,"is_corresponding":false},{"id":576943,"name":"Li Wu","orcid":"0000-0002-5468-2487","position":2,"is_corresponding":false},{"id":1079552,"name":"Hua Yang","orcid":"0000-0002-7248-9410","position":0,"is_corresponding":true}],"reference_count":71,"raw_metadata":null,"created_at":"2026-07-19T02:49:18.751199Z","pmid":"40434097","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}