Venoms of Iranian Scorpions (Arachnida, Scorpiones) and Their Potential for Drug Discovery

Scorpions, a characteristic group of arthropods, are among the earliest diverging arachnids, dating back almost 440 million years. One of the many interesting aspects of scorpions is that they have venom arsenals for capturing prey and defending against predators, which may play a critical role in their evolutionary success. Unfortunately, however, scorpion envenomation represents a serious health problem in several countries, including Iran. Iran is acknowledged as an area with a high richness of scorpion species and families. The diversity of the scorpion fauna in Iran is the subject of this review, in which we report a total of 78 species and subspecies in 19 genera and four families. We also list some of the toxins or genes studied from five species, including Androctonus crassicauda, Hottentotta zagrosensis, Mesobuthus phillipsi, Odontobuthus doriae, and Hemiscorpius lepturus, in the Buthidae and Hemiscorpiidae families. Lastly, we review the diverse functions of typical toxins from the Iranian scorpion species, including their medical applications.

TsNTxP, a non-toxic protein from Tityus serrulatus scorpion venom, induces antinociceptive effects by suppressing glutamate release in mice

Neuropathic pain is a common type of chronic pain caused by trauma or chemotherapy. However, this type of pain is undertreated. TsNTxP is a non-toxic protein isolated from the venom of the scorpion Tityus serrulatus, and it is structurally similar to neurotoxins that interact with voltage-gated sodium channels. However, the antinociceptive properties of this protein have not been characterized. The purpose of this study was to investigate the antinociceptive effects of TsNTxP in acute and neuropathic pain models. Male and female Swiss mice (25-30 g) were exposed to different models of acute pain (tail-flick test and nociception caused by capsaicin intraplantar injection) or neuropathic pain (chronic pain syndrome induced by paclitaxel or chronic constriction injury of the sciatic nerve). Hypersensitivity to mechanical or cold stimuli were evaluated in the models of neuropathic pain. The ability of TsNTxP to alter the release of glutamate in mouse spinal cord synaptosomes was also evaluated. The results showed that TsNTxP exerted antinociceptive effects in the tail-flick test to a thermal stimulus and in the intraplantar capsaicin administration model. Furthermore, TsNTxP was non-toxic and exerted antiallodynic effects in neuropathic pain models induced by chronic constriction injury of the sciatic nerve and administration of paclitaxel. TsNTxP reduced glutamate release from mouse spinal cord synaptosomes following stimulation with potassium chloride (KCl) or capsaicin. Thus, this T. serrulatus protein may be a promising non-toxic drug for the treatment of neuropathic pain.

Allergens of Blomia tropicalis: An Overview of Recombinant Molecules

Allergic diseases are considered a major problem for healthcare systems in both developed and developing countries. House dust mites are well-known triggers of allergic manifestations. While the Dermatophagoides genus is widely distributed globally, Blomia tropicalis is the most prominent mite species in the tropical and subtropical regions of the world. Over the last decades, an increase in sensitization rates to B. tropicalis has been reported, leading to increased research efforts on Blomia allergens. In fact, 8 new allergens have been identified and characterized to different degrees. Here, we provide an overview of recent developments concerning the identification and production of recombinant Blomia allergens, as well as their structural and immunological characterization. Although considerable progress has been achieved, detailed molecule-based studies are still needed to better define the clinical relevance of Blomia allergens. Thus, the establishment of a well-standardized and fully characterized panel of allergens remains a challenge for the development of better diagnosis and therapy of allergic diseases induced by B. tropicalis.

[Experimental study on the Der f 1 mRNA molecules derived from dermatophagoides farinae for specific immunotherapy on murine model of asthma]

OBJECTIVE

To investigate the effect of Der f 1 mRNA molecules for specific immunotherapy on murine model of asthma.

METHODS

Fifty BALB/c mice were randomly divided into 5 groups: PBS group, Der f 1 sensitization group, Der f 1 specific immunotherapy (SIT) group, beta-actin mRNA SIT group, and Derf 1 mRNA SIT group. On days 0, 7 and 14, mice in PBS group received PBS injection; mice in the other groups were intraperitoneally injected with 10 microg Derf 1. At day 21, the mice in the 4 experimental groups were challenged with a 30-min inhaled dose of Der f 1 (100 microg/ml) for 7 successive days. Two weeks after the final sensitization, the mice in the above five groups were im- munized by intradermal injection with PBS, 1 microg Der f 1, 10 microg Der f 1, 2 microg beta-actin mRNA, and 2 microg Der f 1 mRNA, respectively for 3 times at one-week intervals. Two weeks after the last intradermal injection, all mice were sacrificed and bronchoalveolar lavage fluid (BALF) was collected. ELISA was performed to detect the levels of IFN-gamma and IL-13 in BALF, the number of eosinophils in the BALF was recorded. Splenocytes were prepared, and cultured with Der f 1 al- lergen (10 Jg/ml) for 72 h. Splenocytes of PBS group was cultured without Derf 1 allergen. The levels of IFN-gamma and IL-13 in splenocyte culture supernatant were measured by ELISA, as well as serum antibody levels of total IgE, allergen- specific IgE (sIgE), sIgG1, and sIgG2a. Lung sections were stained in hematoxylin and eosin, and observed under the microsope.

RESULTS

Except for PBS group, mice in the other 4 group showed symptoms of acute asthma attack. Com- pared with Derf 1 sensitization group [(897.56 +/- 105.73) pg/ml] and beta-actin mRNA SIT group [(219.47 +/- 64.72) pg/ml], the level of IFN-gamma in BALF from Der f 1 mRNA SIT group [(897.56 +/- 105.73) pg/ml] and Derfl SIT group [(864.48 +/- 70.62)pg/ml] significantly increased (P<0.01). However, the level of IL-13 in BALF from Derf 1 mRNA SIT group [(241.64 +/- 31.41) pg/ml] and Derf 1 SIT group [(321.94 +/- 41.07)pg/ml] was significantly lower than that of Der f 1 sensitization group [(520.62 +/- 43.77) pg/ml] and beta-actin mRNA SIT group [(507.22 +/- 42.26) pg/ml](P<0.01). The number of eosinophils in Der f 1 mRNA SIT group [(1.33 +/- 0.44) x 10(5)/ml] and Der f 1 SIT group [(1.48 +/- 0.39) x 10(5)/ml] was also lower than that of Der f 1 sensitization group [(3.54 +/- 0.52)x10(5)/ml] and beta-actin mRNA SIT group [(2.98-0.53) x 10(5)/ml] (P<0.01). The levels of IFN-GAMMA and IL-13 in splenocyte culture supernatant showed that IFN-gamma level in Der f 1 mRNA SIT group [(420.91+69.92) pg/ml] and Der f 1 SIT group [(334.92 +/- 43.72) pg/ml] was significantly higher than that of Der f 1 sensitization group[(123.75 +/- 5.48) pg/ml] and beta-actin mRNA SIT group[(128.84 +/- 59.00) pg/ml] (P<0.01). However, IL-13 level of Der f 1 mRNA SIT group [(268.51 +/- 40.42) pg/ml] and Der f 1 SIT group [(285.26 +/- 62.21) pg/ml] was significantly lower than that of Derf 1 sensitization group [(613.89 +/- 51.54) pg/ml] and beta-actin mRNA SIT group [(524.05 +/- 39.12) pg/ml] (P<0.01). Compared with Der f 1 sensitization group [total IgE: (94.34 +/- 11.66) ng/ml, sIgE: (65.67 +/- 9.47) ng/ml, sIgG1: (75.18 +/- 9.52) ng/ml, sIgG2a: (2.81 +/- 1.17) ng/ml] and beta-actin mRNA SIT group[total IgE: (86.48 +/- 10.26) ng/ml, sIgE: (62.36 +/- 8.35) ng/ml, sIgG1: (69.51 +/- 8.98) ng/ml, IgG2a: (1.06 +/- 0.11) ng/ml], the serum antibody levels of total IgE [(33.72 +/- 9.78) ng/ml], sIgE [(22.76 +/- 8.09) ng/ml], sIgG1 [(17.87 +/- 7.59) ng/ml] of Der f 1 mRNA SIT group decreased significantly (P<0.01), whereas the level of IgG% [(7.74 +/- 0.88) ng/ml] increased (P<0.01). Compared with Der f 1 sensitization group, the asthmatic symptoms were relieved after immunization with Der f 1 mRNA for specific immunotherapy, including intact structure of respiratory and alveolar epithelial cells, decreased inflammatory cell infiltration, and similar to those in Der f 1 SIT group. However, the breakage and detachment of bronchial epithelial cells occurred in beta-actin mRNA SIT group.

CONCLUSION

Derf 1 mRNA vaccine can correct Th1 and Th2 imbalance.

Design of a ProDer f 1 vaccine delivered by the MHC class II pathway of antigen presentation and analysis of the effectiveness for specific immunotherapy

Dermatophagoides farinae (Der f 1) is one of leading cause for allergic asthma, and allergen-specific immunotherapy (SIT) is currently recognized as the only etiological therapy to ameliorate asthmatic symptom. The current study was designed on the major histocompatibility complex (MHC) class II pathway, invariant chain (Ii)-segment hybrids as vaccine basis to explore the efficacy of Der f 1 hybrid vaccine by virtue of Ii as carrier in enhancing the protective immune response to asthma. Initially, we engineered a fused molecule, DCP-IhC-ProDer f 1, to deliver ProDer f 1 antigen via specific dendritic cell-targeting peptides to dendritic cells (DCs). Then the DCP-IhC-ProDer f 1 was immunized to the asthmatic models of murine induced by ProDer f 1 allergen. The findings showed that the cytokine repertoire in the murine model was shifted after SIT, including stronger secretion of IFN-γ and IL-10, and a decreased production of IL-4 and IL-17. ELISA determination revealed that the hybrid displayed weak IgE and IgG1 reactivities, and IgG2a levels were elevated. Furthermore, DCP-IhC-ProDer f 1 treatment inhibited inflammatory cell infiltration in the lung tissues. Our results suggest that the DCP-Ihc-ProDer f 1 may be used as a candidate SIT against asthma.

[[Expression of house dust mite allergens Der f1 and Der f2 in Nicotiana benthamiana leaves]

The class E immunoglobulins (IgE) is known to recognize conformational epitopes and therefore the native conformation of recombinant allergens is essential for their using in test-systems. Recombinant Dermatophagoides farinae house dust mite (HDM) allergens Der f1 and Der f2 were expressed in bacteria Escherichia coli and Nicotiana benthamiana plants. It has been shown that IgE in sera from children allergic to HDM recognizes Der f2 expressed both in E. coli and N. benthamiana. Mature form of Der f1 expressed in E. coli does not interact with IgE while the protein purified from N. benthamiana is able to recognize IgE as a native allergen.