Nortriptyline Alters Cytokines and Phagocytic Readout in Murine Macrophages

Nortriptyline changed selected cytokine outputs and reduced a phagocytosis-associated assay response in activated J774.2 murine macrophages, according to an in vitro laboratory study. The effects depended on cytokine and concentration: 5 micrograms per milliliter of nortriptyline reduced the proportion of active pHrodo assay effectors from 77% to 45% in the stimulated comparison condition. The experiment involved a mouse macrophage cell line under controlled culture conditions, and its results do not establish comparable effects in people or animals in vivo.

Researchers exposed J774.2 cells to nortriptyline at 1, 3, or 5 micrograms per milliliter under basal or LPS-stimulated conditions. LPS was used at 1 microgram per milliliter. Cell viability remained above 85% across all three nortriptyline concentrations, indicating that the treatments were non-cytotoxic within the evaluated range. The investigators quantified extracellular secretion of tumor necrosis factor alpha, IL-12p40, IL-6, and GM-CSF with enzyme-linked immunosorbent assays. They separately assessed the functional phagocytic response using fluorogenic pHrodo Green E. coli BioParticles and flow cytometry, allowing changes in cytokine secretion to be compared with a distinct cellular activity readout.

The cytokine results did not form a uniform pattern of suppression. Under LPS challenge, nortriptyline produced a numerical concentration-dependent decrease in tumor necrosis factor alpha, reaching approximately 6,342 picograms per milliliter, although the reported comparison for this trend was not statistically significant. IL-12p40 was significantly and concentration-dependently suppressed, declining to approximately 5,767 picograms per milliliter, with P less than 0.01. IL-6 showed a contrasting dose-dependent response. Co-treatment with 1 microgram per milliliter of nortriptyline yielded about 5,700 picograms per milliliter, higher than the LPS-only comparison, whereas 5 micrograms per milliliter significantly reduced IL-6 to approximately 3,100 picograms per milliliter relative to LPS alone. The findings therefore indicate that nortriptyline’s measured effects varied among cytokines rather than uniformly lowering every inflammatory output.

At the highest concentration tested, nortriptyline also significantly reduced the phagocytosis-associated signal generated by the pHrodo assay. The proportion of active effector cells fell from 77% in the stimulated comparison condition to 45% after treatment with 5 micrograms per milliliter of nortriptyline. Because this result was obtained from fluorogenic pHrodo E. coli bioparticles analyzed by flow cytometry, it is specifically a pHrodo-associated readout rather than a comprehensive measure of macrophage behavior. The study supports the conclusion that nortriptyline can alter selected inflammatory outputs and reduce this functional response in J774.2 cells under the tested conditions. Its scope is limited to one murine macrophage cell line, an in vitro design, LPS-stimulated and basal cultures, and a finite concentration range. Although major depressive disorder is frequently associated with immune-inflammatory activation, the experiments do not show that these cellular changes explain nortriptyline’s clinical effects or predict treatment responses in patients.

Subject of Research: In vitro immunomodulatory effects of nortriptyline in activated J774.2 murine macrophages

Article Title: Nortriptyline exerts context-dependent cytokine modulation and reduces pHrodo-associated phagocytic response in activated J774.2 macrophages

Article References: Öktem, M., Yurtseven, B., Aydemir, E., & Ayaz, F. (2026). Nortriptyline exerts context-dependent cytokine modulation and reduces pHrodo-associated phagocytic response in activated J774.2 macrophages. Molecular Biology Reports, 53(1), Article 1485. https://doi.org/10.1007/s11033-026-12656-3

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DOI: 10.1007/s11033-026-12656-3

Keywords: nortriptyline, murine macrophages, J774.2 cells, cytokine secretion, phagocytic response, immune modulation, LPS stimulation, in vitro research, exerts, context-dependent, cytokine, modulation