Hemiscorpius lepturus venom induces expression and production of interluckin-12 in human monocytes

F1 fraction isolated from Mesobuthus eupeus scorpion venom induces macrophage polarization toward M1 phenotype and exerts anti-tumoral effects on the CT26 tumor cell line

Scorpion venoms identified as agents with anti-tumor and anti-angiogenic features. Tumor microenvironment (TME) plays a pivotal role in the process of tumorigenesis, tumor development, and polarization of M2 phenotype tumor associated macrophages (TAMs). M2 polarized cells are associated with tumor growth, invasion, and metastasis. The fractionation process was performed by gel filtration chromatography on a Sephadex G50 column. To elucidate whether scorpion venom can alter macrophage polarization, we treated interleukin (IL)-4-polarized M2 cells with isolated fractions from Mesobuthus eupeus. Next, we evaluated the cytokine production and specific markers expression for M2 and M1 phenotype using enzyme linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (PCR), respectively. The phagocytic capacity of macrophages was also assessed. In addition, the migration assay and MTT analysis were performed to investigate the effects of reprogrammed macrophages on the CT-26 colon cancer cells. The results indicated that F1 fraction of venom significantly upregulated the levels and expression of M1-associated cytokines and markers, including tumor necrosis factor-alpha (TNF-α) (p < 0.001), IL-1 (p < 0.01), interferon regulatory factor 5 (IRF5) (p < 0.0001), induced nitric oxide synthase (iNOS) (p < 0.0001), and CD86 (p < 0.0001), and downregulated M2-related markers, including transforming growth factor-beta (TGF-β) (p < 0.05), IL-10 (p < 0.05), Fizz1 (p < 0.0001), arginase-1 (Arg-1) (p < 0.0001), and CD206 (p < 0.001). The macrophage phagocytic capacity was enhanced after treatment with F1 fraction (p < 0.01). Moreover, incubation of CT-26 cell line with conditioned media of F1-treated macrophages suppressed migration (p < 0.0001) and proliferation (p < 0.01) of tumor cells. In conclusion, our findings demonstrated the potential of Mesobuthus eupeus venom in M2-to-M1 macrophage polarization as a promising therapeutic approach against proliferation and metastasis of colon cancer cells.

Effect of water-soluble PM10 on the production of TNF-α by human monocytes and induction of apoptosis in A549 human lung epithelial cells

Long-term exposure to airborne particles of 10 µm and less in size (PM₁₀) in dust can lead to increased risk of diseases such as respiratory, cardiovascular, lung cancer and atherosclerosis. The aim of the study was to evaluate the effects of water-soluble PM₁₀ particles in the Middle East Dust (MED) storm in Ahvaz, Iran, on the production of TNF-α by human monocytes. In addition, we assessed the level of induction of apoptosis in isolated A549 human pulmonary epithelial cells. For this purpose, isolated human blood monocytes (250,000 to 300,000 cell/ ml) as well as isolated human pulmonary A549 epithelial cells (100,0000 cell/ ml) were exposed to various concentrations (62.5, 125, 250, 500 µg/ml) of water-soluble PM₁₀ particles for different incubation periods (12, 24, 48 h). The results showed that exposure to PM₁₀ particles increased the production of TNF-α in human monocytes and promoted apoptosis induction in A549 cells, in both concentration and incubation of period-dependent manner. In conclusion, airborne dust particles in Ahvaz city contain active compounds capable of increasing production of the pro-inflammatory cytokine, TNF-α, and inducing apoptosis of lung epithelial cells.

Effect of 5-aminolevulinic acid on gene expression and presence of NKG2D receptor on NK cells

Natural killer (NK) cells are involved in innate and acquired immunity, stimulating and enhancing immune responses via secretion of IFN-γ and TNF-α. NKG2D is among the most important NK's stimulant receptors, the ligands of which are elevated on cancerous and virus-infected cells. We analyzed effect of 5-ALA on gene expression and receptor presentation of NKG2D, which is present on peripheral blood NK cells. Mononuclear cells were isolated from the venous blood samples of healthy individuals. RNA extraction and cDNA synthesis were performed after exposure of samples to 5-ALA, and gene expression was evaluated using Real-Time PCR, and the receptor presence rate on the cell surface was evaluated by flow-cytometry analysis. The results showed the gene expression of NKG2D and the presence of its receptor on NK cells were increased.5-ALA can be used to activate NK cells in their killing activity, preventing the growth and metastasis of cancerous cells.

Venom components of the scorpion Centruroides limpidus modulate cytokine expression by T helper lymphocytes: Identification of ion channel-related toxins by mass spectrometry

The study of the effector mechanisms of T helper cells has revealed different phenotypic characteristics that can be manipulated for designing new therapeutic schemes in different pathological scenarios. Ion channels are significant targets in T lymphocyte modulation since they are closely related to their effector activity. Remarkably, some toxins produced by scorpions specifically affect the function of these membrane proteins. For that reason, these toxins are important candidates in the search for new immunomodulators. Here, the effect of two venom fractions of the scorpion Centruroides limpidus was assessed on T lymphocyte proliferation and cytokine production. The venom fractions ClF8 and ClF9 were separated by reversed-phase high-performance liquid chromatography (RP-HPLC) and cultured at 25 and 35 µg/ml with murine T lymphocytes. The results indicate that the fraction ClF8 increased both production and secretion levels of IFN-γ, IL-4, IL-17A and IL-10 by CD4⁺ T cells at 24 h. In contrast, fraction ClF9 only promoted the secretion of IL-17A and IL-10 at its highest concentration (35 µg/ml). Both fractions did not show any effect on T cell proliferation. Subsequent analyses by liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed seventeen toxins in the fraction ClF8 and five toxins in the fraction ClF9, most of them with voltage-gated sodium (NaScTx) and potassium (KScTx) channels as molecular targets. These toxins might probably interact with ion channels involved in T lymphocyte activity. Our findings suggest that the difference in composition between the two fractions could be related to the observed effects, and the components identified could be isolated to search for possible immunomodulatory molecules.

A. crassicauda, M. eupeus and H. lepturus scorpion venoms initiate a strong in vivo anticancer immune response in CT26-tumor mice model

In the present in vivo study the anticancer efficacy of the venoms from Androctonus crassicauda, Messobuthus eupeus and Hemiscorpius lepturus scorpions was investigated. In addition, we attempted to clarify whether the immune system is involved in this activity. Initially, the LD₅₀ of the venoms from these scorpions were determined and their 0.1 and 0.2 LD₅₀ were calculated. The toxicity of 0.1 and 0.2 LD₅₀ was tested on healthy mice by daily SC administration of these venoms for 12 consecutive days. CT26 cells were inoculated by SC route in BALB/c mice to establish a sold tumor, and ten days later, the mice were treated with 0.1 and 0.2 LD₅₀ doses of the venoms on daily basis for 12 consecutive days. The tumor volume was measured every 4 days. At day 13, the tumors from untreated-control and venom-treated groups were removed, weighed, and assessed by histopathological and immunohistochemical techniques. In addition, the levels of mRNA expression of IL-12, IFN-γ and IL-1β were measured by real-time PCR. All the venoms induced anticancer effects as evidenced by significant inhibition in tumor growth; significant increases in inflammatory and CD⁺-T cells and expression of mRNA IL-12 and IFN-γ in tumor microenvironment of venom-treated as compared to untreated-control. These findings demonstrated, for the first time, that sub-lethal doses of the venoms from these scorpions induce their in vivo anticancer effects by stimulating the immune system. Further studies, specifically designed to identify these active constituents are recommended.

Differential effect of Androctonus australis hector venom components on macrophage KV channels: electrophysiological characterization

Neurotoxins of scorpion venoms modulate ion channels. Voltage-gated potassium (K_V) channels regulate the membrane potential and are involved in the activation and proliferation of immune cells. Macrophages are key components of the inflammatory response induced by scorpion venom. The present study was undertaken to investigate the effect of Androctonus australis hector (Aah) venom on K_V channels in murine resident peritoneal macrophages. The cytotoxicity of the venom was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) -based assay and electrophysiological recordings were performed using the whole-cell patch clamp technique. High doses of Aah venom (50, 125, 250 and 500 µg/ml) significantly decreased cell viability, while concentrations of 0.1-25 µg/ml were not cytotoxic towards peritoneal macrophages. Electrophysiological data revealed a differential block of K_V current between resting and LPS-activated macrophages. Aah venom significantly reduced K_V current amplitude by 62.5 ± 4.78% (n = 8, p < 0.05), reduced the use-dependent decay of the current, decreased the degree of inactivation and decelerated the inactivation process of K_V current in LPS-activated macrophages. Unlike cloned K_V1.5 channels, Aah venom exerted a similar blocking effect on K_V1.3 compared to K_V current in LPS-activated macrophages, along with a hyperpolarizing shift in the voltage dependence of K_V1.3 inactivation, indicating a direct mechanism of current inhibition by targeting K_V1.3 subunits. The obtained results, demonstrating that Aah venom differentially targets K_V channels in macrophages, suggest differential outcomes for their inhibitions, and that further investigations of scorpion venom immunomodulatory potential are required.

Immune drug discovery from venoms

This review catalogues recent advances in knowledge on venoms as standalone therapeutic agents or as blueprints for drug design, with an emphasis on venom-derived compounds that affects the immune system. We discuss venoms and venom-derived compounds that affect total immune cell numbers, immune cell proliferation, immune cell migration, immune cell phenotype and cytokine secretion. Identifying novel compounds that 'tune' the system, up-regulating the immune response during infectious disease and cancer and down-regulating the immune response during autoimmunity, will greatly expand the tool kit of human immunotherapeutics. Targeting these pathways may also open therapeutic options that alleviate symptoms of envenomation. Finally, combining recent advances in venomics with progress in low cost, high-throughput screening platforms will no doubt yield hundreds of prototype immune modulating compounds in the coming years.

Selected scorpion toxin exposures induce cytokine release in human peripheral blood mononuclear cells

A cytokine screening on human peripheral blood mononuclear cells (PBMCs) stimulated with selected scorpion toxins (ScTx's) was performed in order to evaluate their effect on human immune cells. The ScTx's chosen for this report were three typical buthid scorpion venom peptides, one with lethal effects on mammals Centruroides suffussus suffusus toxin II (CssII), another, with lethal effects on insects and crustaceans Centruroides noxius toxin 5 (Cn5), and one more without lethal effects Tityus discrepans toxin (Discrepin). A Luminex multiplex analysis was performed in order to determine the amounts chemokines and cytokines IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12-p40, IL-13, interferon alpha (IFN-α), interferon gamma (IFN-γ), tumor necrosis factor alpha TNF-α, and interferon-inducible protein-10 (IP-10) secreted from human PBMCs exposed to these toxins. Although, the ScTx Cn5 is not lethal for mammals, it was able to induce the secretion of cytokines IL-1β, IL-6, and TNF-α, IL-10 and IP-10 in comparison to the lethal CssII, which was able to induce only IP-10 secretion. Discrepin also was able to induce only IP-10. Interestingly, only low amounts of interferons α and β were induced in the presence of the ScTx's assayed. In a synergic experiment, the combination of Discrepin and Cn5 displayed considerable reverse effects on induction of IL-1β, IL-6, IL-10 and TNF-α, but they had a slight synergic effect on IP-10 cytokine production in comparison with the single effect obtained with the Cn5 alone. Thus, the results obtained suggest that the profile of secreted cytokines promoted by ScTx Cn5 is highly related with a cytokine storm event, and also it suggests that the mammalian lethal neurotoxins are not solely responsible of the scorpion envenomation symptomatology.

TNF-alpha modulates adipose macrophage polarization to M1 phenotype in response to scorpion venom

OBJECTIVE

We previously reported that Androctonus australis hector (Aah) venom and its toxic fraction affect adipose tissue metabolism. However, the contribution of immune system and the role of adipose tissue macrophages (ATMs) in the progression of inflammation induced by scorpion venom remain largely unknown.

METHODS

Here we evaluate the capacity of the toxic fraction of Aah venom (FTox-G50) to induce the expression of M1 and M2 markers genes on adipose tissue and isolated stromal vascular cells (SVC). Quantitative real-time PCR was performed on the SVC 24 h after FTox-G50 venom injection to assess the gene expressions of IL12p40, IL23, and other macrophages-associated markers.

RESULTS

We found that ATM from FTox-G50-venom-injected mice markedly increased the expressions of IL-12p40 and IL-23. Furthermore, the expression of nitric oxide synthase 2 (an M1 marker) was up-regulated, but the expression of Arginase1 (an M2 marker) was not. Systemic injection of a chemical inhibitor directed against TNF-α binding reduced the expression of inflammatory M1 macrophage markers and the MAPKpk2 gene, a key mediator of inflammatory signaling.

CONCLUSION

These results indicate that TNF-α is a physiological regulator of inflammation and macrophage activation induced by scorpion venom.