Delta-9-tetrahydrocannabinol alleviates inflammation by modulating immune responses in LPS-induced murine inflammation model

Delta-9-THC reduced inflammatory immune signaling across human immune cells and a mouse model of systemic inflammation. In LPS-stimulated cells, THC markedly suppressed type I interferon-related genes and pro-inflammatory cytokines including IL-1β and TNF-α, while also reducing immune-cell activation markers.

The effects extended beyond isolated cells. In mice exposed to systemic inflammation, THC reduced activation of splenic myeloid cells and T cells. Brain analysis also showed reduced neuroinflammatory signaling, including lower expression of inflammatory mediators, while pathways associated with neurogenesis, synaptic plasticity and neuronal function were enriched.

Importantly, the researchers describe THC’s effects as modulation rather than indiscriminate immune suppression, concluding that THC appears to dampen excessive inflammatory signaling while influencing cellular stress-adaptation pathways. They say these findings support further investigation of cannabinoid signaling in chronic inflammatory, neuroimmune and neurodegenerative disorders.

“Introduction: Δ9-Tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, has been reported to modulate immune responses; however, its effects on complex innate immune signaling pathways and inflammation remain incompletely understood. Here, we investigated the immunomodulatory effects of THC on lipopolysaccharide (LPS)-induced inflammation across cellular and in vivo models.

Methods: We integrated transcriptomic, cellular, and in vivo approaches to characterize the effects of THC on innate immune activation. Human THP-1 monocytic cells were treated with THC in the presence or absence of LPS, followed by transcriptomic and gene expression analyses to evaluate inflammatory, type I interferon, unfolded protein response (UPR), and autophagy pathways. Findings were validated in primary human monocytes by assessing immune activation markers. The effects of chronic THC exposure were further evaluated in a murine model of systemic inflammation by examining splenic myeloid and T-cell activation. RNA sequencing of brain tissue was performed to assess the effects of THC on neuroinflammatory and neuronal pathways.

Results: THC induced a stress-adaptive transcriptional program in THP-1 cells, characterized by upregulation of genes associated with the UPR and autophagy pathways. In contrast, THC markedly suppressed LPS-induced type I interferon-stimulated genes (ISGs) and pro-inflammatory cytokines, including IL-1β and TNF-α. In primary human monocytes, THC significantly reduced the expression of activation markers CD80, CD83, and CD209. Consistent with these findings, chronic THC exposure attenuated the activation of splenic myeloid and T cells in mice subjected to systemic inflammation. Brain transcriptomic analysis further demonstrated reduced expression of neuroinflammatory pathways following THC exposure, accompanied by enrichment of pathways associated with neurogenesis and synaptic plasticity.

Discussion: Our findings demonstrate that THC exerts broad immunomodulatory effects characterized by suppression of inflammatory and type I interferon responses while promoting cellular stress-adaptation pathways. These effects were observed across human monocytic cells, primary monocytes, and peripheral immune populations in vivo, and were accompanied by reduced neuroinflammatory signaling and increased neuronal plasticity-associated pathways in the brain. Together, these findings provide mechanistic insight into the immunomodulatory actions of THC and support further investigation of cannabinoid signaling as a potential regulator of chronic inflammatory and neuroimmune disorders.”

https://pubmed.ncbi.nlm.nih.gov/42818626

“Chronic THC exposure reduces LPS-induced immune activation in vivo.”

https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2026.1856131/full

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Δ9-Tetrahydrocannabinol treatment impairs CD8+ T cell differentiation into interferon gamma-competent CD45RO+ cells

New research published in The Journal of Pharmacology and Experimental Therapeutics shows that Δ9-tetrahydrocannabinol (THC) can alter the development of CD8+ T cells involved in inflammatory immune responses. Researchers found that THC reduced secretion of interferon gamma (IFNγ), interleukin-2 (IL-2), and tumor necrosis factor alpha (TNFα), three signaling molecules involved in immune activation and inflammation.

Rather than simply preventing cells from producing IFNγ, THC appeared to change how the T cells developed. THC reduced the differentiation of CD8+ T cells into mature CD45RO+ cells capable of secreting IFNγ. A selective CB2 receptor agonist produced similar effects, suggesting that activation of the cannabinoid CB2 receptor may play an important role in THC’s immune-modulating activity.

The researchers examined these effects partly because IFNγ-producing CD8+ T cells contribute to persistent neuroinflammation associated with HIV-associated neurocognitive disorders. They concluded that reducing CD8+ T-cell-derived IFNγ in the central nervous system may potentially improve cognitive outcomes during HIV infection, while noting that the findings may also have relevance to other inflammatory diseases involving IFNγ-producing CD8+ T cells.

“Chronic human immunodeficiency virus (HIV) infection results in a persistent state of neuroinflammation, even with combined antiretroviral therapy. Neuroinflammation contributes to pathology termed HIV-associated neurocognitive disorder, which is exacerbated by interferon gamma (IFNγ)-producing CD8+ T cells in the central nervous system.

Many people living with HIV self-report using Cannabis sativa to mitigate symptoms of chronic infection and side effects of treatment. C. sativa is composed of various phytocannabinoids, including Δ9-tetrahydrocannbinol (THC), which possesses immune-modulating properties.

This study aims to determine whether C. sativa use by people living with HIV, and specifically THC, affects IFNγ secretion by CD8+ T cells.

We found that HIV status does not influence T cell IFNγ responses, and C sativa use modestly reduces the average secretion of IFNγ by CD8+ T cells from HIV+ donors. Treatment of CD8+ T cells with THC and the selective cannabinoid receptor 2 agonist, JWH-015, reduced T-cell cytokine secretion, with THC eliciting greater suppression than cannabidiol.

These results suggest that THC treatment does not directly impair IFNγ gene expression or protein production, as determined by polymerase chain reaction and flow cytometry. However, THC treatment impaired CD8+ T cell differentiation into IFNγ-competent CD45RO+ cells.

These studies are of clinical relevance because reduction of CD8+ T-cell-derived IFNγ in the central nervous system may improve cognitive outcomes during HIV infection. Furthermore, these findings may be generalizable to other inflammatory diseases in which IFNγ-producing CD8+ T cells have been implicated.

SIGNIFICANCE STATEMENT: Δ9-Tetrahydrocannbinol (THC) treatment reduces CD8+ T cell interferon gamma (IFNγ) secretion isolated from HIV- and HIV+ individuals. THC and the selective cannabinoid receptor 2 agonist, JWH-015, both reduced CD8+ T cell secretion of IFNγ, interleukin 2, and tumor necrosis factor α, suggesting the involvement of cannabinoid receptor 2. Although THC treatment does not suppress IFNγ mRNA or protein levels, it reduces the number of IFNγ-secreting cells by impairing CD8+ T-cell differentiation into IFNγ-competent CD45RO+ cells.”

https://pubmed.ncbi.nlm.nih.gov/42748512

https://jpet.aspetjournals.org/article/S0022-3565(26)01210-3/abstract

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Delta-8-tetrahydrocannabinol ameliorates murine autoimmune hepatitis and is associated with epigenetic modulation of immune responses

A new 2026 study published in International Immunopharmacology found that delta-8-tetrahydrocannabinol (Δ8-THC) significantly reduced autoimmune hepatitis in mice while altering the immune responses responsible for liver inflammation. Researchers found that Δ8-THC reduced inflammatory immune cells and helped preserve immune cells involved in protecting the liver.

The researchers also uncovered a possible mechanism. Δ8-THC increased two microRNAs, miR-100-5p and miR-199a-3p, which suppressed mTOR signaling and shifted CD4+ T-cell development away from inflammatory Th1 and Th17 cells and toward regulatory T cells that help control excessive immune activity.

The authors concluded that Δ8-THC showed both hepatoprotective and anti-inflammatory activity and highlighted its potential therapeutic value for autoimmune and inflammatory disorders. The study adds new evidence that cannabinoids may influence disease not only by reducing inflammation, but by changing the molecular and epigenetic pathways that regulate immune responses.

“Aim of the study: Cannabinoids have gained attention for their ability to modulate immune responses and suppress inflammation. However, the effect of Δ8-THC, a minor cannabinoid found in Cannabis, has not been explored in autoimmune hepatitis. To address knowledge gap, the present study aimed to investigate the hepatoprotective and immunoregulatory properties of Δ8-THC in experimental autoimmune hepatitis and to identify molecular and epigenetic mechanisms underlying its immunoregulatory effects.

Methods: miRNA sequencing and flow cytometric analysis were performed using hepatic immune cells from female C57BL/6 mice treated with ConA (12.5 mg/kg, i.v.) and Δ8-THC (20 mg/kg, i.p.). Differential miRNA expressions were analyzed using the edgeR, and miRNA targets were predicted using Ingenuity Pathway Analysis. Target gene expression was validated by qRT-PCR and Western blot. Functional assays including miRNA mimic/inhibitor transfection and CD4+ T-cell differentiation were performed to validate target gene regulation by miRNAs and its role in CD4+ T-cell differentiation.

Results: Δ8-THC markedly suppressed ConA-induced autoimmune hepatitis by restoring immune homeostasis within the liver through suppression of inflammatory monocytes, neutrophils, and natural killer cells, and preservation of tolerogenic Kupffer cells. In addition, Δ8-THC reshaped the hepatic lymphoid compartment, diminishing inflammatory CD4+ T-cell responses while favoring regulatory T-cell expansion. These effects were associated with the preservation of miR-100-5p and miR-199a-3p expression in the liver, whereas both miRNAs were markedly downregulated following ConA treatment. mTOR, a central regulator of T-cell differentiation, was identified as a target of these miRNAs. Consistent with these findings, Δ8-THC reduced mTOR expression and upregulated hepatoprotective miRNAs in both in vivo and in vitro models. Functional analyses with miRNA overexpression and inhibition approaches verified the direct regulation of mTOR by these miRNAs in T cells and RAW 264.7 cells. In naïve CD4+ T cells, miRNA gain- and loss-of-function experiments demonstrated that miR-100-5p/miR-199a-3p-mediated suppression of mTOR promotes regulatory T-cell differentiation while limiting Th1 and Th17 polarization.

Conclusion: Our results identify Δ8-THC as a promising hepatoprotective and anti-inflammatory compound that ameliorates ConA-induced autoimmune hepatitis by influencing CD4+ T-cell differentiation potentially through the miR-100-5p/miR-199a-3p-mTOR axis, highlighting its potential therapeutic value in autoimmune and inflammatory disorders.”

https://pubmed.ncbi.nlm.nih.gov/42753324

“In conclusion, our findings suggest that Δ8-THC can mitigate ConA-induced hepatitis, potentially through epigenetic regulation involving microRNAs. Specifically, Δ8-THC improved liver function and reduced systemic and intrahepatic inflammation in ConA-exposed mice. These effects were associated with increased expression of miR-100-5p and miR-199a-3p in the liver, suggesting that these miRNAs may regulate mTOR signaling and contribute to the suppression of proinflammatory responses and promotion of anti-inflammatory pathways. Functional studies supported the involvement of these miRNAs in the regulation of mTOR signaling, CD4+ T-cell differentiation, and inflammatory responses.”

https://www.sciencedirect.com/science/article/pii/S1567576926012518?via%3Dihub