Sea Anemone Kunitz-Type Peptides Demonstrate Neuroprotective Activity in the 6-Hydroxydopamine Induced Neurotoxicity Model

Abstract

Kunitz-type peptides from venomous animals have been known to inhibit different proteinases and also to modulate ion channels and receptors, demonstrating analgesic, anti-inflammatory, anti-histamine and many other biological activities. At present, there is evidence of their neuroprotective effects. We have studied eight Kunitz-type peptides of the sea anemone Heteractis crispa to find molecules with cytoprotective activity in the 6-OHDA-induced neurotoxicity model on neuroblastoma Neuro-2a cells. It has been shown that only five peptides significantly increase the viability of neuronal cells treated with 6-OHDA. The TRPV1 channel blocker, HCRG21, has revealed the neuroprotective effect that could be indirect evidence of TRPV1 involvement in the disorders associated with neurodegeneration. The pre-incubation of Neuro-2a cells with HCRG21 followed by 6-OHDA treatment has resulted in a prominent reduction in ROS production compared the untreated cells. It is possible that the observed effect is due to the ability of the peptide act as an efficient free-radical scavenger. One more leader peptide, InhVJ, has shown a neuroprotective activity and has been studied at concentrations of 0.01-10.0 µM. The target of InhVJ is still unknown, but it was the best of all eight homologous peptides in an absolute cell viability increment on 38% of the control in the 6-OHDA-induced neurotoxicity model. The targets of the other three active peptides remain unknown.

TRPV1 Blocker HCRG21 Suppresses TNF-α Production and Prevents the Development of Edema and Hypersensitivity in Carrageenan-Induced Acute Local Inflammation

“…The yield of the recombinant HCRG21 was 8.2 mg/L cell culture (OD A600 = 0.8). The measured molecular weight of peptide was 6228.5 Da, which corresponded to the calculated data and earlier published results [13,17]. According to the 1 H NMR spectrum the peptide had a well-defined fold.…”

“…It is the first peptide blocker of this channel (inhibits up to 95% of the currents, IC 50 6.9 µM) [13] and has a prolonged analgesic effect (up to 13 h) in the model of thermal pain stimulation [14]. We previously demonstrated that HCRG21 was able to suppress the synthesis of reactive oxygen species in nerve cells and increased their survival in a model of 6-hydroxydopamine-induced neurotoxicity that imitates in vitro Parkinson's disease tightly associated with neuroinflammation [17]. In this study, the potential of HCRG21 was revealed as an effective anti-inflammatory compound.…”

Kunitz-Type Peptides from Sea Anemones Protect Neuronal Cells against Parkinson’s Disease Inductors via Inhibition of ROS Production and ATP-Induced P2X7 Receptor Activation

“…The peptides have an approximately equal content of secondary structural elements, while a slight increase in α-helixes and decrease in β-structure were found in HCIQ1c9 (Table 1), which might be reflected in the spatial structure and biological activity of the peptide. A comparison of peptide structures with the Kunitz-type peptides InhVJ from H. crispa [44] and SHPI-1 from S. helianthus [53], revealed similar values of secondary structural elements.…”

“…The presence of mutations in Kunitz-type peptides does not affect the spatial molecule structure but leads to the appearance of diverse biological activities toward various targets [39][40][41][42]. Recently, we demonstrated that Kunitz-type peptides of the sea anemone Heteractis crispa inhibit neuroblastoma cell death induced by 6-OHDA via ROS production reductions or antiradical activity [43,44]. Furthermore, some of them demonstrated anti-inflammatory, antihistamine, and analgesic activities [45][46][47][48][49][50], which might also facilitate decreases in both inflammatory and oxidative stress processes inside neuronal cells.…”

AsKC11, a Kunitz Peptide from Anemonia sulcata, Is a Novel Activator of G Protein-Coupled Inward-Rectifier Potassium Channels

“…In the sequence of these peptide toxins, the Kunitz motif is a cysteine-rich peptide chain of ~60 amino acid residues with an alpha and beta fold, stabilized by three conserved disulfide bridges [26]. Kunitztype peptides are not only found in sea anemones, but also snakes, spiders, scorpions, and cone snails [27]. They show diverse biological activities, such as inhibition of proteases and/or blocking or modulating ion channels [26].…”