Neuropathophysiological effect and immuno-inflammatory response induced by kaliotoxin of androctonus scorpion venom

Comparative Proteomic Analysis of the Venoms from the Most Dangerous Scorpions in Morocco: Androctonus mauritanicus and Buthus occitanus

Morocco is known to harbor two of the world's most dangerous scorpion species: the black Androctonus mauritanicus (Am) and the yellow Buthus occitanus (Bo), responsible for 83% and 14% of severe envenomation cases, respectively. Scorpion venom is a mixture of biological molecules of variable structures and activities, most of which are proteins of low molecular weights referred to as toxins. In addition to toxins, scorpion venoms also contain biogenic amines, polyamines, and enzymes. With the aim of investigating the composition of the Am and Bo venoms, we conducted an analysis of the venoms by mass spectrometry (ESI-MS) after separation by reversed-phase HPLC chromatography. Results from a total of 19 fractions obtained for the Am venom versus 22 fractions for the Bo venom allowed the identification of approximately 410 and 252 molecular masses, respectively. In both venoms, the most abundant toxins were found to range between 2-5 kDa and 6-8 kDa. This proteomic analysis not only allowed the drawing of an extensive mass fingerprint of the Androctonus mauritanicus and Buthus occitanus venoms but also provided a better insight into the nature of their toxins.

Induced pathophysiological alterations by the venoms of the most dangerous Moroccan scorpions Androctonus mauretanicus and Buthus occitanus: A comparative pathophysiological and toxic-symptoms study

Scorpion envenomation is a serious public health issue. Androctonus mauretanicus (Am) and Buthus occitanus (Bo) are the most dangerous scorpions in Morocco. Despite their medical relevance, no study has yet related their kinetics of symptom apparition and the consequent tissue disorders at the same interval post-injection. This work achieved the first comparative pathophysiological and toxic-symptoms study between the Am and Bo venoms from a biochemical, toxicological and physiopathological standpoint. The activity of venoms and their subletal dose were determined by administration of increasing concentrations of the venoms. 30, 60 and 120 min following the experimental envenomation in mice, the profile of clinical symptoms was underlined and the main organs: brain, heart, lungs, liver and kidneys were removed for histological examination. The Am venom is a rich source of proteins and three-times more toxic than the Bo. The most observed clinical symptoms are neurological and cardiopulmonary. The Am venom caused histopathological alterations at 30, 60, and 120 min which were more important than the Bo. This study highlighted that both venoms exhibited a strong toxicity with variable intensities. Moreover, we showed the presence of correlation between the level of histopathological disorders observed and the intensity of signs appeared at the same time following venom inoculation.

Immunomodulatory and protective effects of interleukin-4 on the neuropathological alterations induced by a potassium channel blocker

The pathophysiology of neurological diseases related to potassium-channel dysfunction such as epilepsy is increasingly linked to immune system modulation. However, there are limited reports of which interleukin-4 (IL-4) can act on the neuroinflammatory response after seizure. Hence, we evaluated the effect of IL-4 in murine model of neuroexcitotoxcity using kaliotoxin (KTx), a potassium-channel blocker. Results showed that IL-4 treatment can significantly reduce the neuronal death induced by KTx. Probably by decreasing mitochondria swelling, reversing oxidative damage and enhancing Bcl-2 expression. Furthermore, IL-4 treatment significantly reduced TNF-α expression and enhanced GFAP and IL-10 expressions in the brain. IL-4 can be neuroprotective in epileptogenesis.

Neuro-Modulation of Immuno-Endocrine Response Induced by Kaliotoxin of Androctonus Scorpion Venom

Kaliotoxin (KTX), a specific blocker of potassium channels, exerts various toxic effects due to its action on the central nervous system. Its use in experimental model could help the understanding of the cellular and molecular mechanisms involved in the neuropathological processes related to potassium channel dysfunctions. In this study, the ability of KTX to stimulate neuro-immuno-endocrine axis was investigated. As results, the intracerebroventricular injection of KTX leads to severe structural-functional alterations of both hypothalamus and thyroid. These alterations were characterized by a massive release of hormones' markers of thyroid function associated with damaged tissue which was infiltrated by inflammatory cell and an imbalanced redox status. Taken together, these data highlight that KTX is able to modulate the neuro-endocrine response after binding to its targets leading to the hypothalamus and the thyroid stimulation, probably by inflammatory response activation and the installation of oxidative stress in these organs.

K(+) channel blocker-induced neuroinflammatory response and neurological disorders: immunomodulatory effects of astaxanthin

OBJECTIVE

Channelopathies due to the brain ion channel dysfunction is considered to be an important mechanism involved in various neurodegenerative diseases. In this study, we evaluated the ability of kaliotoxin (KTX) as K(+) channel blocker to induce neuro-inflammatory response and neurodegenerative alteration. We also investigate the effects of astaxanthin (ATX) against KTX disorders.

MATERIAL AND TREATMENT

NMRI mice were injected with KTX (1 pg/kg, by i.c.v route) with or without pretreatment using ATX (80 mg/kg, o.p route).

RESULTS

Results showed that KTX was detected in cerebral cortex area due to its binding to the specific receptors (immunofluorescence analysis). It induced an activation of inflammatory cascade characterized by an increase of IL-6, TNFα, NO, MDA levels and NF-κB expression associated to a decrease of GSH level. The neuroinflammatory response is accompanied with cerebral alterations and blood-brain barrier (BBB) disruption. The use of ATX prior to the KTX exerts a preventive effect not only on the neuroinflammation but also on altered tissues and the BBB disruption.

CONCLUSIONS

Kaliotoxin is able to induce neurological disorders by blocking the K(+) ion channel, and ATX suppresses this alterations with down regulation of IL-6, TNF-α and NF-κB expression in the brain.

Systemic responses following brain injuries and inflammatory process activation induced by a neurotoxin of Androctonus scorpion venom

OBJECTIVE

Kaliotoxin 2 (KTX2), a neurotoxin isolated from Androctonus australis hector scorpion venom, presents a high affinity with the voltage-gated potassium channels. The targets of KTX2 in the brain and its toxic effects on the cerebral cortex have been extensively studied; however, its deleterious systemic effects on other organ systems have not yet been investigated. Inflammatory response induced by KTX2 is supported by cytokine release which could provoke multiple organ dysfunction and diverse biological disorders in mammals. The possibility that inflammatory response and brain injuries induced by KTX2 may lead to functional disturbances, e.g. in the pancreas and the liver, were investigated. The contribution of IL-6 and TNF-α to the modulation of pathophysiological effects induced by KTX2 was also tested.

METHODS

NMRI mice were injected by the intracerebroventricular route with a sublethal dose of KTX2 or saline solution. Inflammatory response and oxidative stress were assessed in sera and tissue homogenates. Biomarkers of pancreatic and hepatic functions and the correlation with tissue damage in the brain, liver and pancreas were also analyzed.

RESULTS

The obtained results revealed that KTX2 injection induced an inflammatory process activation and imbalanced redox status. It also induced severe alterations in cerebral cortex, hepatic and pancreatic tissues associated with a significant increase in pancreatic and hepatic pathological biomarkers. Cytokine antagonists injected 30 min prior to KTX2 led to a significant reduction of all disturbances induced by KTX2.

CONCLUSION

In addition to its significant toxicity on the central nervous system, KTX2 can also affect pancreatic and hepatic functions, probably by an indirect mechanism involving activation of the inflammatory response with release of IL-6 and TNF-α.