With the emergence of the covid-19 pandemic, research into inhibiting the cytokine release syndrome or cytokine storm, has become extremely relevant. In the master's thesis, we focused on the establishment and evaluation of cellular models of excessive cytokine release. These enable the evaluation of new drugs and therapeutic approaches that could inhibit or reduce the release of proinflammatory cytokines.
We aimed to establish suitable in vitro models of excessive cytokine release that would mimic in vivo conditions as closely as possible. For this purpose, we used cell lines representing immune cells, such as Jurkat for lymphocytes T, THP-1 for monocytes and lymphoblastoid cell lines (LCL), which are obtained from lymphocytes B of healthy donors. The cell lines were treated with selected compounds that could potentially increase the release of cytokines. We measured the concentrations of secreted clinically relevant cytokines IL-8, IL-1β, IL-6, IL-10, TNFα and IL-12p70 after 24 hours by flow cytometry.
We found that activation of Jurkat cells with a combination of ionomycin/PMA increased the release of cytokines IL-8 and TNFα. Treatment of THP-1 cells with the combination of ionomycin/PMA/LPS activated the highest release of cytokines IL-8, IL-6, IL-1β, TNFα and IL-10. Treatment of LCL cells with the combination of ionomycin/PMA increased the release of IL-8, IL-6, TNFα and IL-12p70. Pre-treatment of activated LCL 1823 cells with dexamethasone and cyclosporin A statistically significantly reduced the concentrations of proinflammatory cytokines TNFα, IL-6, IL-8, thus confirming the suitability of the in vitro cell model for evaluation of the immunomodulatory effects of novel compounds.
Next, LCL cells were used to evaluate the immunomodulatory properties of constitutive proteasome (cP) and immunoproteasome (iP) inhibitors. The proteasome has an important role in the regulation of the transcription factor NF-κB, which controls the expression of proinflammatory cytokines. We idetified cP inhibitors as more cytotoxic compared to iP inhibitors in tested immune cells. Moreover, six out of eleven cP and iP inhibitors statistically significantly decreasedthe release of cytokines. We confirmed that cP and iP inhibitors inhibit the TNFα-activated NF-κB signaling pathway on Ramos-Blue reporter cells.
Based on the results, we can conclude that LCL cells are an suitable in vitro model of excessive cytokine release. We found that iP inhibitors are less cytotoxic than cP inhibitors. Further research would be worthwhile to evaluate the immunomodulatory properties of cP and iP inhibitors.
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