Biochemical Characterization of HL-7 and HL-10 Peptides Identified from Scorpion Venom of Hemiscorpius lepturus

Biomedical applications of synthetic peptides derived from venom of animal origin: A systematic review

Development of therapeutic agents that have fewer adverse effects and have higher efficacy for diseases, such as cancer, metabolic disorders, neurological diseases, infections, cardiovascular diseases, and respiratory diseases, are required. Recent studies have focused on identifying novel sources for pharmaceutical molecules to develop therapies against these diseases. Among the sources for potentially new therapies, animal venom-derived molecules have generated much interest. Various animal venom-derived proteins and peptides have been isolated, identified, synthesized, and tested to develop drugs. Venom-derived peptides have several biomedical properties, such as proapoptotic, cell migration, and autophagy regulation activities in cancer cell models; induction of vasodilation by nitric oxide and regulation of angiotensin II; modification of insulin response by controlling calcium and potassium channels; regulation of pain receptor activity; modulation of immune cell activity; alteration of motor neuron activity; degradation or inhibition of β-amyloid plaque formation; antibacterial, antifungal, antiviral, and antiprotozoal activities; increase in sperm motility and potentiation of erectile function; reduction of intraocular pressure; anticoagulation, fibrinolytic, and antithrombotic activities; etc. This systematic review compiles these biomedical properties and potential biomedical applications of synthesized animal venom-derived peptides reported in the latest research. In addition, the limitations and areas of opportunity in this research field are discussed so that new studies can be developed based on the data presented.

Evaluation of the in vivo antihypertensive effect and antioxidant activity of HL-7 and HL-10 peptide in mice

BACKGROUND

The tendency to use bioactive peptides has increased in recent decades, and research would be essential for recognizing the therapeutic effects of peptides present in animals or food resource. In this study, the in vivo antioxidant and antihypertensive properties of peptides HL-7 with the sequence of YLYELR and HL-10 with the sequence of AFPYYGHHLG were identified from scorpion venom of H. lepturus were evaluated.

METHODS AND RESULTS

To study the in vivo effects of peptides, D-galactose-induced and DOCA salt-induced mice models were used. The results of the antioxidant assay for both peptides showed that the activity of serum and liver catalase (CAT), as well as superoxide dismutase (SOD) enzymes, was significantly decreased in the D-galactose-induced group (NC), while MDA levels were increased in serum and the liver tissue samples (p < 0.01). Compared with the D-galactose-induced mice, the peptide treated mice group had a higher activity of antioxidant enzymes namely CAT and SOD, as well as a lower lipid peroxidation level. Also, the results of antihypertensive activity for both peptides showed that systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the mice treated with the HL-7 and HL-10 peptides were significantly reduced in a dose-dependent manner (p < 0.01). The administration of the HL-7 peptide at doses of 2 mg/kg BW (LP1), 5 mg/kg BW (-IP1) and 15 mg/kg BW (HP1) significantly diminished the mean arterial blood pressure (MAP) by 11 mmHg, 31 mmHg and 40.47 mmHg, respectively. Accordingly, treatment of mice with the HL-10 peptide at doses of 2 mg/kg BW (LP2), 5 mg/kg BW (IP2) and 15 mg/kg BW (HP2) considerably lowered the MAP by 8 mmHg, 18.3 mmHg and 21.93 mmHg, respectively.

CONCLUSION

Our findings suggest that both the HL-7 and HL-10 peptides could be potentially utilized as antihypertensive and antioxidant components.

NMR three-dimensional structure of the cationic peptide Stigmurin from Tityus stigmurus scorpion venom: In vitro antioxidant and in vivo antibacterial and healing activity

Infectious diseases and the rapid development of pathogens resistant to conventional drugs are a serious global public health problem, which motivates the search for new pharmacological agents. In this context, cationic peptides without disulfide bridges from different species of scorpion venom have been the target of scientific studies due to their multifunctional activities. Stigmurin is a linear peptide composed of 17 amino acid residues (Phe-Phe-Ser-Leu-Ile-Pro-Ser-Leu-Val-Gly-Gly-Leu-Ile-Ser-Ala-Phe-Lys-NH₂), which is present in the venom gland of the scorpion Tityus stigmurus. Here we present investigations of the in vitro antioxidant action of Stigmurin together with the in vivo antibacterial and healing activity of this peptide in a wound infection model induced by Staphylococcus aureus. In addition, we have reports for the first time of the three-dimensional structure determined by NMR spectroscopy of a peptide without disulfide bridges present in scorpion venom from the Tityus genus. Stigmurin showed hydroxyl radical scavenging above 70 % at 10 μM and antibiotic action in the skin wound, reducing the number of viable microorganisms by 67.2 % on the 7 day after infection. Stigmurin (1 μg / μL) increased the retraction rate of the lesion, with wound area reduction of 43 % on the second day after skin injury, which indicates its ability to induce tissue repair. Stigmurin in trifluoroethanol:water exhibited a random conformation at the N-terminus region (Phe1 to Pro6), with a helical structure from Ser7 to Phe16. This structural information, allied with the multifunctional activity of Stigmurin, makes it an attractive candidate for the design of novel therapeutic agents.