University of Toronto researchers show reengineered long noncoding RNAs reduce inflammation in macrophages and mice

# University of Toronto Researchers Report Reengineered Long Noncoding RNAs Reduce Inflammation in Macrophages and Mice in Science Signaling Researchers at the University of Toronto and The Hospital for Sick Children (SickKids) in Toronto, Canada, report that naturally occurring long noncoding RNAs can be reengineered and delivered exogenously to suppress acute inflammation in human macrophages and mouse models, according to a study published March 10, 2026, in Science Signaling. The work positions lncRNA therapeutics inflammation as a previously uncharacterized nucleic acid drug modality distinct from siRNA, antisense oligonucleotides, and mRNA. The study, led by Pang et al. and funded through multiple Canadian research programs including the Canada First Research Excellence Fund and the Canadian Institutes of Health Research, synthesized three anti-inflammatory lncRNAs — GAPLINC, MIST, and DRAIR — via in vitro transcription, purified them by reverse-phase HPLC, and delivered them in lipid nanoparticles to LPS-challenged cells and animals. Each lncRNA modulated a distinct arm of the NF-κB inflammatory signaling cascade, and the lead candidate, GAPLINC, achieved broad multi-cytokine suppression in vivo at doses as low as 0.10 mg/kg with no observed organ toxicity. The concept of a long noncoding RNA drug — a full-length, non-protein-coding transcript delivered from outside the cell to recapitulate its native regulatory function — has no direct precedent in clinical or late-stage preclinical development. Existing RNA therapeutic platforms from Alnylam, Ionis, and Moderna focus on short interfering RNAs, antisense oligonucleotides, or protein-encoding mRNAs. The Toronto group's approach instead co-opts the endogenous gene-regulatory machinery that lncRNAs engage, aiming to rebalance inflammatory signaling rather than block a single downstream effector. The study screened three lncRNAs across four chemical modification states — unmodified, pseudouridine (Ψ), N1-methylpseudouridine (m1Ψ), and 5-methylcytosine (m5C) — in RAW-Dual mouse macrophage reporter cells carrying NF-κB and IRF pathway readouts. GAPLINC emerged as the lead. Its Ψ-modified form reduced LPS-induced NF-κB activation by approximately 40–50% relative to LPS-only controls (p < 0.05), while scrambled and irrelevant lncRNA controls had no effect. IRF pathway activity was largely unchanged, indicating selectivity for NF-κB. Neither a 5′ cap nor a 3′ poly(A) tail — structural features central to mRNA therapeutic design — enhanced GAPLINC's activity, and in some configurations they diminished it, underscoring that anti-inflammatory lncRNA macrophages engage cellular targets through mechanisms fundamentally different from translated mRNAs. MIST showed modest NF-κB suppression in certain modification states but lacked the consistency of GAPLINC. DRAIR produced limited effects in the reporter system. GAPLINC was therefore advanced to in vivo testing. In C57BL/6 mice challenged intraperitoneally with 100 μg LPS, intravenous administration of Ψ-modified GAPLINC encapsulated in lipid nanoparticles reduced serum TNF-α by approximately 50–70% and IL-6 by 40–60% compared to LPS-only controls, with statistical significance ranging from p < 0.05 to p < 0.0001 across experiments. IL-1β, MCP-1, IFN-γ, and GM-CSF were also suppressed. The anti-inflammatory cytokine IL-10 showed variable changes, consistent with selective dampening of pro-inflammatory pathways rather than blanket immunosuppression. RT-qPCR from splenic and hepatic tissue confirmed reduced Tnf, Il1b, and Il6 transcript levels. The lipid nanoparticle RNA delivery system used custom ionizable lipids — C3-K2-E14 for in vitro work and OC2-K3-E10 for in vivo studies — formulated via microfluidics at optimized nanomaterial-to-RNA mass ratios. At a 20:1 ratio, encapsulation efficiency exceeded 85%, particle size fell within 80–120 nm, and polydispersity remained below 0.2. Biodistribution studies using luciferase mRNA as a reporter confirmed accumulation in liver and spleen, organs rich in the macrophage populations relevant to LPS-induced inflammation treatment. A dose-response study at 0.10, 1.0, 3.0, and 5.0 mg/kg identified 3.0 mg/kg as the threshold for robust cytokine suppression, with 5.0 mg/kg offering marginal additional benefit. A time-course study showed maximal separation between treated and control groups at 6 hours post-LPS, with continued suppression at 10 hours and convergence by 24 hours as inflammation naturally resolved. An 8-day tolerability study involving two LNP administrations produced no body weight loss and no histopathological abnormalities in liver, spleen, or kidneys. Administration of GAPLINC-LNP without LPS challenge did not elevate pro-inflammatory cytokines above baseline, indicating the construct itself was not immunostimulatory. Each of the three lncRNAs operated through a distinct mechanism. GAPLINC transcriptionally suppressed Il1b expression, with kinetics comparable to siRNA-mediated knockdown but with broader multi-cytokine effects from a single molecule. MIST reduced TNF-α protein without altering Tnf transcript levels at any timepoint, pointing to a posttranscriptional mechanism. DRAIR reduced Il6 transcription at 6 hours, consistent with its known epigenetic activity, and uniquely increased IL-10, suggesting it promotes a shift toward an anti-inflammatory macrophage phenotype. Chemical modifications altered which cytokines each lncRNA affected, establishing base modification as a tunable parameter for noncoding RNA therapeutics — a finding with no direct parallel in the mRNA field, where pseudouridine primarily reduces immunogenicity and enhances translation rather than changing the encoded protein's function. Human translational data provided an additional dimension. GAPLINC, originally a human lncRNA with high sequence homology to its mouse ortholog, suppressed TNF-α and IL-6 transcript levels in PBMC-derived monocytes and macrophages from both female and male donors (p < 0.05), confirming cross-species activity. The competitive landscape for this technology is sparse at the therapeutic level but flanked on multiple sides. CAMP4 Therapeutics and Omega Therapeutics target lncRNA-regulated loci but do not deliver exogenous lncRNAs. Ionis Pharmaceuticals uses antisense oligonucleotides to degrade pathogenic lncRNAs — the opposite strategy. Approved anti-cytokine biologics including adalimumab, tocilizumab, and anakinra block individual downstream mediators of NF-κB signaling but do not modulate upstream regulatory circuits. Corticosteroids suppress NF-κB broadly but carry well-documented systemic toxicities. Prior clinical attempts to target the TLR4/NF-κB axis directly — including eritoran and resatorvid in sepsis trials — failed to demonstrate sufficient efficacy as monotherapies. No clinical trials investigating reengineered lncRNA therapeutics for any indication are registered on ClinicalTrials.gov. No regulatory designations or industry partnerships have been disclosed. The work remains at the preclinical proof-of-concept stage. As the authors stated in the paper: "Unlike small-molecule drug discovery campaigns, the function, compatibility, safety, and utility of lncRNA have already been generally established through evolution. Despite their potential, lncRNAs are exclusively used as diagnostic markers or drug targets. In contrast, we report the production, optimization, deployment, and mechanisms of action of lncRNAs that have been reengineered as therapeutics." The editor's summary in Science Signaling noted that the findings "demonstrate the potential utility of lncRNAs for treating acute inflammation and open the door for the development of lncRNA-based therapies to treat other conditions." Translation to clinical development will require formal toxicology studies, manufacturing scale-up for large structured RNAs, and resolution of delivery challenges that remain more complex for lncRNAs than for the short RNA payloads that dominate the current RNA therapeutics pipeline. Meta description: Science Signaling study shows reengineered lncRNAs delivered via lipid nanoparticles suppress LPS-induced multi-cytokine inflammation in macrophages and mice. --- Spot something wrong? [Report an issue with this article](https://newsgen-prod.reframedata.com/feedback/long-noncoding-rnas-university-of-toronto)