B109-22 Smoke-induced Epithelial Reprogramming Creates a Permissive Niche for HIV-1 Infection Using an Immunomodulatory Competing Endogenous RNA Network

Rationale

Despite effective suppression of systemic HIV replication by combined antiretroviral therapy (cART), persistent viral reservoirs within tissues remain a major obstacle to cure. The airway epithelium has recently emerged as an underrecognized reservoir capable of harboring integrated HIV provirus and sustaining low-level viral transcription. People living with HIV (PLWH) who smoke suffer disproportionate pulmonary morbidity, yet the mechanisms by which tobacco smoke (TS) potentiates viral persistence in airway epithelium are poorly understood. Long noncoding RNAs (lncRNAs) can function as competing endogenous RNAs (ceRNAs), modulating gene expression by sequestering regulatory miRNAs. We recently identified LIMASI (LncRNA Inflammatory and Mucous associated, Antisense to ICAM1) as a rapid stress-inducible lncRNA in airway epithelial cells. We hypothesized that TS establishes a ceRNA-driven regulatory network in which LIMASI promotes ICAM-1-dependent airway epithelial reprogramming, thereby creating a permissive, inducible HIV reservoir.

Methods

Primary human airway epithelial cells (HAECs) differentiated at air-liquid interface were exposed to tobacco smoke extract (TSE) and infected with R5-tropic HIV-1BaL. HIV proviral transcription (LTR qPCR) and productive replication (p24 ELISA) were measured in apical washes, basolateral media, and cell lysates ± antiretroviral therapy. ICAM-1, IL-6, CXCL-8, and MUC5AC were assessed by qRT-PCR and immunostaining. LIMASI expression and subcellular localization were evaluated by qRT-PCR and RNA-FISH. Lung tissues from nonhuman primates (NHPs) exposed to tobacco smoke (TS) and/or simian-adapted HIV (SHIV) were analyzed for in-vivo validation and compared with control NHPs exposed to filtered-air (FA). LIMASI-miRNA interactions were predicted using the IntaRNA 2.0 webserver.

Results

TSE exposure induced epithelial reprogramming characterized by elevated LIMASI, ICAM-1, and MUC5AC expression. HAECs supported productive HIV-1 infection and retained proviral transcription despite antiretroviral treatment, consistent with reservoir-like behavior. TSE significantly enhanced viral replication (∼62 pg/ml vs ∼37 pg/ml p24 at 24h) and induced ICAM-1 expression. HIV infection alone upregulated LIMASI, while combined TSE+HIV exposure resulted in a 3-fold induction over non-treated controls. In NHPs, TS+SHIV exposure recapitulated increased LIMASI expression (>7-fold higher), mucous remodeling, and airway inflammation. Computational modeling supported a ceRNA mechanism whereby LIMASI competitively binds miRNAs (miR-122-5p, miR-150-5p, and miR-155-5p) associated with ICAM-1-mediated inflammation and HIV infection, consistent with coordinated upregulation of ICAM-1 and mucous expression following TS and HIV exposure.

Conclusions

Collectively, these findings identify a LIMASI-centered ceRNA network that links tobacco smoke exposure to ICAM-1-dependent airway epithelial reprogramming and HIV persistence in the smokers’ lungs. Targeting this ceRNA axis may offer a novel strategy for lung reservoir-directed therapies in PLWH who smoke.

This abstract is funded by: None