OXYGEN MITIGATES THE INFLAMMATORY RESPONSE IN A MODEL OF HEMORRHAGE AND ZYMOSAN-INDUCED INFLAMMATION

Evaluation of Anti-Inflammatory Activity of the New Cardiotonic Steroid γ-Benzylidene Digoxin 8 (BD-8) in Mice

Cardiotonic steroids are known to bind to Na+/K+-ATPase and regulate several biological processes, including the immune response. The synthetic cardiotonic steroid γ-Benzylidene Digoxin 8 (BD-8) is emerging as a promising immunomodulatory molecule, although it has remained largely unexplored. Therefore, we tested the immunomodulatory potential of BD-8 both in vitro and in vivo. Hence, primary mouse macrophages were incubated with combinations of BD-8 and the pro-inflammatory fungal protein zymosan (ZYM). Nitric oxide (NO) production was determined by Griess reagent and cytokines production was assessed by enzyme-linked immunosorbent assay. Inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS), p-nuclear factor kappa B p65 (NF-κB p65), p-extracellular signal-regulated kinase (p-ERK), and p-p38 were evaluated by flow cytometry. Macrophages exposed to BD-8 displayed reduced phagocytic activity, NO levels, and production of the proinflammatory cytokine IL-1β induced by ZYM. Furthermore, BD-8 diminished the expression of iNOS and phosphorylation of NF-κB p65, ERK, and p38. Additionally, BD-8 exhibited anti-inflammatory capacity in vivo in a carrageenan-induced mouse paw edema model. Taken together, these findings demonstrate the anti-inflammatory activity of BD-8 and further reinforce the potential of cardiotonic steroids and their derivatives as immunomodulatory molecules.

Zymosan Particle-Induced Hemodynamic, Cytokine and Blood Cell Changes in Pigs: An Innate Immune Stimulation Model with Relevance to Cytokine Storm Syndrome and Severe COVID-19

Hemodynamic disturbance, a rise in neutrophil-to-lymphocyte ratio (NLR) and release of inflammatory cytokines into blood, is a bad prognostic indicator in severe COVID-19 and other diseases involving cytokine storm syndrome (CSS). The purpose of this study was to explore if zymosan, a known stimulator of the innate immune system, could reproduce these changes in pigs. Pigs were instrumented for hemodynamic analysis and, after i.v. administration of zymosan, serial blood samples were taken to measure blood cell changes, cytokine gene transcription in PBMC and blood levels of inflammatory cytokines, using qPCR and ELISA. Zymosan bolus (0.1 mg/kg) elicited transient hemodynamic disturbance within minutes without detectable cytokine or blood cell changes. In contrast, infusion of 1 mg/kg zymosan triggered maximal pulmonary hypertension with tachycardia, lasting for 30 min. This was followed by a transient granulopenia and then, up to 6 h, major granulocytosis, resulting in a 3-4-fold increase in NLR. These changes were paralleled by massive transcription and/or rise in IL-6, TNF-alpha, CCL-2, CXCL-10, and IL-1RA in blood. There was significant correlation between lymphopenia and IL-6 gene expression. We conclude that the presented model may enable mechanistic studies on late-stage COVID-19 and CSS, as well as streamlined drug testing against these conditions.

Interleukin-1β and cathepsin D modulate formation of the terminal complement complex in cultured human disc tissue

PURPOSE

Formation of terminal complement complex (TCC), a downstream complement system activation product inducing inflammatory processes and cell lysis, has been identified in degenerated discs. However, it remains unclear which molecular factors regulate complement activation during disc degeneration (DD). This study investigated a possible involvement of the pro-inflammatory cytokine interleukin-1β (IL-1β) and the lysosomal protease cathepsin D (CTSD).

METHODS

Disc biopsies were collected from patients suffering from DD (n = 43) and adolescent idiopathic scoliosis (AIS, n = 13). Standardized tissue punches and isolated cells from nucleus pulposus (NP), annulus fibrosus (AF) and endplate (EP) were stimulated with 5% human serum (HS) alone or in combination with IL-1β, CTSD or zymosan. TCC formation and modulation by the complement regulatory proteins CD46, CD55 and CD59 were analysed.

RESULTS

In DD tissue cultures, IL-1β stimulation decreased the percentage of TCC + cells in AF and EP (P < 0.05), whereas CTSD stimulation significantly increased TCC deposition in NP (P < 0.01) and zymosan in EP (P < 0.05). Overall, the expression of CD46, CD55 and CD59 significantly increased in all isolated cells during culture (P < 0.05). Moreover, cellular TCC deposition was HS concentration dependent but unaffected by IL-1β, CTSD or zymosan.

CONCLUSION

These results suggest a functional relevance of IL-1β and CTSD in modulating TCC formation in DD, with differences between tissue regions. Although strong TCC deposition may represent a degeneration-associated event, IL-1β may inhibit it. In contrast, TCC formation was shown to be triggered by CTSD, indicating a multifunctional involvement in disc pathophysiology.

The pterocarpanquinone LQB 118 inhibits inflammation triggered by zymosan in vivo and in vitro

LQB 118, a hydride molecule, has been described as an antineoplastic and antiparasitic drug. Recently, LQB118 was also shown to display anti-inflammatory properties using an LPS-induced lung inflammation model. However, LQB 118 effects on the inflammatory response induced by zymosan has not been demonstrated. In this study, swiss mice were LQB 118 intraperitoneally (i.p.) treated and zymosan was used to induce peritoneal inflammation. Peritoneal fluid was collected and used for cell counting and proinflammatory cytokines quantification (IL-1β, IL-6, and TNF-α) by immunoenzymatic assay (ELISA). For in vitro studies, peritoneal macrophages zymosan-stimulated were used. Results demonstrated that LQB 118 treatment reduced polymorphonuclear cell migration and TNF-α, IL-1β, and IL-6 levels in the peritoneal cavity. In macrophages, LQB 118 treatment display no cytotoxic effect and is also able to reduce cytokines levels. To investigate LQB 118 putative mechanism of action, TLR2, CD69, and P-p38 MAPK expression were evaluated. LQB 118 treatment reduced CD69 expression and p38 phosphorylation induced by zymosan. Furthermore, LQB 118 was able to negatively modulate TLR2 expression in the presence of inflammatory stimulus. Thus, our study provide new evidences for the mechanisms related to the anti-inflammatory effect of LQB 118 in vivo and in vitro.