Whole transcriptome sequencing reveals the activity of the PLA2 family members in Androctonus crassicauda (Scorpionida: Buthidae) venom gland

Phospholipase A2 is the most abundant venom gland enzyme, whose activity leads to the activation of the inflammatory response by accumulating lipid mediators. This study aimed to identify, classify, and investigate the properties of venom PLA2 isoforms. Then, the present findings were confirmed by chemically measuring the activity of PLA2. The sequences representing PLA2 annotation were extracted from the Androctonus crassicauda transcriptome dataset using BLAS searches against the local PLA2 database. We found several cDNA sequences of PLA2 classified and named by conducting multiple searches as platelet-activating factor acetylhydrolases, calcium-dependent PLA2s, calcium-independent PLA2s, and secreted PLA2s. The largest and smallest isoforms of these proteins range between approximately 70.34 kDa (iPLA2) and 17.75 kDa (cPLA2). Among sPLA2 isoforms, sPLA2GXIIA and sPLA2G3 with ORF encoding 169 and 299 amino acids are the smallest and largest secreted PLA2, respectively. These results collectively suggested that A. crassicauda venom has PLA2 activity, and the members of this protein family may have important biological roles in lipid metabolism. This study also revealed the interaction between members of PLA2s in the PPI network. The results of this study would greatly help with the classification, evolutionary relationships, and interactions between PLA2 family proteins in the gene network.

Effective Soybean Oil Degumming by Immobilized Phospholipases A2 from Walterinnesia aegyptia Venom

Enzymatic degumming utilizing phospholipase enzymes could be used in ecologically friendly procedures with enhanced oil recovery yields. In this study, two phospholipases A2 of group I and II, WaPLA2-I and WaPLA2-II, from the snake venom of Saudi Walterinnesia aegyptia were evaluated for soybean oil degumming after being immobilized on three different support materials (calcium alginate (CA), CA-gelatin (CAG), and CA-chitosan (CAC), and cross-linked with glutaraldehyde). Higher yields of CAC-immobilized PLA2-I (85 ± 3%) and PLA2-II (87 ± 3.6%) compared to CAG (77.3 ± 2.1 and 79 ± 2.6%, respectively) and CA beads (55.7 ± 2.5% and 57.3 ± 3.1%, respectively) were observed. In addition, the optimal temperature of immobilized WaPLA2-I and WaPLA2-II increased from 45 to 55 °C and from 55 to 65 °C, respectively. Their stability at high temperatures was also significantly enhanced covering a larger range (70-80 °C). Likewise, the pH/activity profile of WaPLA2 was greatly expanded upon immobilization with the pH-optima being shifted by 0.5 to 1 pH unit to the basic side. Similarly, the stability of WaPLA2s in the presence of organic solvents was also significantly improved, while the affinity for calcium and bile salt was the same for both free and immobilized enzymes. Interestingly, the remaining activity of immobilized WaPLA2 onto different supports was more than 50 or 60% after eight recycles or 120 days of storage at 4 °C, respectively. CAC-WaPLA2-II was the best immobilized enzyme complex for the oil degumming process by reducing its final residual phosphorus content from 168 mg/kg to less than 10 mg/kg in only 4 h. Overall, CAC-WaPLA2-II showed the most attractive profiles of temperature, pH, and reaction duration as well as significant storage stability and reusability.

Functional Characterization and Anti-Tumor Effect of a Novel Group II Secreted Phospholipase A2 from Snake Venom of Saudi Cerastes cerates gasperetti

Secreted phospholipases A2 are snake-venom proteins with many biological activities, notably anti-tumor activity. Phospholipases from the same snake type but different geographical locations have shown similar biochemical and biological activities with minor differences in protein sequences. Thus, the discovery of a new phospholipase A2 with unique characteristics identified in a previously studied venom could suggest the origins of these differences. Here, a new Group II secreted phospholipase A2 (Cc-PLA2-II) from the snake venom of Saudi Cerastes cerastes gasperetti was isolated and characterized. The purified enzyme had a molecular weight of 13.945 kDa and showed high specific activity on emulsified phosphatidylcholine of 1560 U/mg at pH 9.5 and 50 °C with strict calcium dependence. Interestingly, stability in extreme pH and high temperatures was observed after enzyme incubation at several pH levels and temperatures. Moreover, a significant dose-dependent cytotoxic anti-tumor effect against six human cancer cell lines was observed with concentrations of Cc-PLA2 ranging from 2.5 to 8 µM. No cytotoxic effect on normal human umbilical-vein endothelial cells was noted. These results suggest that Cc-PLA2-II potentially has angiogenic activity of besides cytotoxicity as part of its anti-tumor mechanism. This study justifies the inclusion of this enzyme in many applications for anticancer drug development.

Egyptian cobra (Naja haje haje) venom phospholipase A2: a promising antiviral agent with potent virucidal activity against simian rotavirus and bovine coronavirus

Viral infections are linked to a variety of human diseases. Despite the achievements made in drug and vaccine development, several viruses still lack preventive vaccines and efficient antiviral compounds. Thus, developing novel antiviral agents is of great concern, particularly the natural products that are promising candidates for such discoveries. In this study, we have purified an approximately 15 kDa basic phospholipase A2 (PLA2) enzyme from the Egyptian cobra Naja haje haje venom. The purified N. haje PLA2 showed a specific activity of 22 units/mg protein against 6 units/mg protein for the whole crude venom with 3.67-fold purification. The antiviral activity of purified N. haje PLA2 has been investigated in vitro against bovine coronavirus (BCoV) and simian rotavirus (RV SA-11). Our results showed that the CC50 of PLA2 were 33.6 and 29 µg/ml against MDBK and MA104 cell lines, respectively. Antiviral analysis of N. haje PLA2 showed an inhibition of BCoV and RV SA-11 infections with a therapeutic index equal to 33.6 and 16, respectively. Moreover, N. haje PLA2 decreased the BCoV and RV SA-11 titers by 4.25 log10 TCID50 and 2.5 log10 TCID50, respectively. Thus, this research suggests the potential antiviral activity of purified N. haje PLA2 against BCoV and RV SA-11 infections in vitro.

Venom of the desert black snake Walterinnesia aegyptia enhances anti-tumor immunity via its beneficial modulatory effects on pro- and anti-tumorigenic inflammatory mediators in cultured colon cancer cells

The role of inflammation in colon cancer is understood as a well-accepted factor that has the tendency to release multiple pro- and anti-tumorigenic inflammatory mediators. Inflammation-induced increased expression of anti-tumorigenic inflammatory mediators and decreased expression of pro-tumorigenic inflammatory mediators encourage beneficial inflammatory effects in terms of powerful anti-tumor immunity. The present study aims to screen the beneficial inflammatory effects of Walterinnesia aegyptia venom via determining its modulatory tendency on the expression of 40 pro- and anti-tumorigenic inflammatory mediators (cytokines/growth factors/chemokines) in LoVo human colon cancer cell line. LoVo-cells were treated with varying doses of crude venom of W. aegyptia. Cell viability was checked utilizing flow cytometry, and IC50 of venom was determined. Venom-induced inflammatory effects were evaluated on the expression of 40 different inflammatory mediators (12 anti-tumorigenic cytokines, 11 pro-tumorigenic cytokines, 7 pro-tumorigenic growth factors, 9 pro-tumorigenic chemokines and 1 anti-tumorigenic chemokine) in treated LoVo-cells [utilizing enzyme-linked immunosorbent assay (ELISA)] and compared with controls. Treatment of venom induced significant cytotoxic effects on inflamed LoVo-cells. IC50 treatment of venom caused significant modulations on the expression of 22 inflammatory mediators in treated LoVo-cells. The beneficial modulatory effects of venom were screened via its capability to significantly increase the expression of five powerful anti-tumorigenic mediators (IL-9, IL-12p40, IL-15, IL-1RA and Fractalkine) and decrease the expression of four major pro-tumorigenic mediators (IL-1β, VEGF, MCP-1 and MCP-3). Walterinnesia aegyptia venom-induced beneficial modulations on the expression of nine crucial pro/anti-tumorigenic inflammatory mediators can be effectively used to enhance powerful anti-tumor immunity against colon cancer.