BjussuMP-II, a venom metalloproteinase, induces the release and cleavage of pro-inflammatory cytokines and disrupts human umbilical vein endothelial cells.

Snake venom metalloproteases (SVMPs) are hydrolytic enzymes dependent on metal binding, primarily zinc (Zn2+), at their catalytic site. They are classified into three classes (P-I to P-III). BjussuMP-II, a P-I SVMP isolated from Bothrops jararacussu snake venom, has a molecular mass of 24 kDa. It exhibits inhibitory activity on platelet aggregation and hydrolyzes fibrinogen. TNF-α upregulates the expression of adhesion molecules on endothelial cell surfaces, promoting leukocyte adhesion and migration during inflammation. Literature indicates that SVMPs may cleave the TNF-α precursor, possibly due to significant homology between metalloproteases from mammalian extracellular matrix and SVMPs. This study aimed to investigate BjussuMP-II's effects on human umbilical vein endothelial cells (HUVEC), focusing on viability, detachment, adhesion, release, and cleavage of TNF-α, IL-1ß, IL-6, IL-8, and IL-10. HUVEC were incubated with BjussuMP-II (1.5-50 µg/mL) for 3-24 h. Viability was determined using LDH release, MTT metabolization, and 7AAD for membrane integrity. Adhesion and detachment were assessed by incubating cells with BjussuMP-II and staining with Giemsa. Cytokines were quantified in HUVEC supernatants using EIA. TNF-α cleavage was evaluated using supernatants from PMA-stimulated cells or recombinant TNF-α. Results demonstrated BjussuMP-II's proteolytic activity on casein. It was not toxic to HUVEC at any concentration or duration studied but interfered with adhesion and promoted detachment. PMA induced TNF-α release by HUVEC, but this effect was not observed with BjussuMP-II, which cleaved TNF-α. Additionally, BjussuMP-II cleaved IL-1ß, IL-6, and IL-10. These findings suggest that the zinc metalloprotease BjussuMP-II could be a valuable biotechnological tool for treating inflammatory disorders involving cytokine deregulation.

Prostaglandin E2 induces ovulation in prepubertal mice / Prostaglandina E2 induz ovulação em camundongos pré-púberes

The objective of this study was to determine the ability of prostaglandin E2 (PGE2) to induce ovulation and expression of PGE2 receptor (EP2 and EP4) and COX genes (COX-1 and COX-2) in the ovary and pituitary of prepubertal mice. The positive control consisted of the application of 5 µg of gonadotropin-releasing hormone (GnRH, n = 29); the negative control applied 0.5 mL of phosphate buffered saline (PBS, n=31); the treatment tested the application of 250 µg of PGE2 (n = 29), making a total of 89 prepubertal mice (BALB/c). Mice were euthanized 14 to 15 h after treatments to detect ovulation and tissue collection. A Chi-square test was used to compare the proportion of animals ovulating. Gene expressions and number of ovulation were analyzed by one-way ANOVA and Tukey's test was used to compare means among groups. A greater proportion of mice (P < 0.001) ovulated after receiving GnRH (89.7%, 26/29) compared to PGE2 group (58.6%, 17/29). However, the proportion was higher compared to those treated with PBS (0%, 0/31). Ep2gene expression in the pituitary was > two-fold higher (P < 0.05) in the PGE2 group compared to the PBS and GnRH groups. Further, PGE2 stimulated Cox1 (2.7 fold, P < 0.05) while GnRH stimulated Cox2 expression (6.5 fold, P < 0.05) in the pituitary when compared to the PBS group. In conclusion, our results support the hypothesis that PGE2 can induce ovulation in prepubertal mice with a concomitant increase in Ep2 and Cox1 gene expression in the pituitary gland.(AU)

O objetivo deste estudo foi determinar a capacidade da prostaglandina E2 (PGE2) em induzir a ovulação e expressão do receptor PGE2 (EP2 e EP4) e genes COX (COX-1 e COX-2) no ovário e na hipófise de camundongos pré-púberes. O controle positivo consistiu na aplicação de 5 µg de hormônio liberador de gonadotrofina (GnRH, n = 29); o controle negativo aplicação 0,5 mL de tampão fosfato-salino (PBS, n=31); o tratamento testado aplicação de 250 µg de PGE2 (n = 29), perfazendo um total de 89 camundongos (BALB/c) pré-púberes. Os camundongos foram sacrificados 14 a 15 h após os tratamentos para detectar ovulações e coleta de tecido. O teste do qui-quadrado foi usado para comparar a proporção de animais ovulando. As expressões gênicas e o número de ovulação foram analisados por ANOVA e o teste de tukey foi usado para comparar as médias entre os grupos. Uma maior proporção de camundongos (P <0,001) ovulou após receber GnRH (89,7%, 26/29) em comparação com o grupo PGE2 (58,6%, 17/29). No entanto, a proporção foi maior em comparação com aqueles tratados com PBS (0%, 0/31). A expressão do gene Ep2 na hipófise foi duas vezes maior (P <0,05) no grupo PGE2 em comparação com os grupos PBS e GnRH. Além disso, a PGE2 estimulou a Cox1(2,7 vezes, P <0,05) enquanto o GnRH estimulou a expressão de Cox2 (6,5 vezes, P <0,05) na pituitária em comparação com o grupo PBS. Em conclusão, nossos resultados suportam a hipótese de que PGE2 é capaz de induzir ovulação em camundongos pré-púberes com aumento concomitante na expressão dos genes Ep2 e Cox1 na glândula pituitária.(AU)

Inflammasome Activation Induced by a Snake Venom Lys49-Phospholipase A2 Homologue.

BACKGROUND: Snake venom phospholipases A2 (PLA2s) have hemolytic, anticoagulant, myotoxic, oedematogenic, bactericidal, and inflammatory actions. BthTX-I, a Lys49-PLA2 isolated from Bothrops jararacussu venom, is an example of Lys49-PLA2 that presents such actions. NLRP3 is a cytosolic receptor from the NLR family responsible for inflammasome activation via caspase-1 activation and IL-1ß liberation. The study of NLRs that recognize tissue damage and activate the inflammasome is relevant in envenomation. METHODS: Male mice (18-20 g) received an intramuscular injection of BthTX-I or sterile saline. The serum was collected for creatine-kinase (CK), lactate dehydrogenase (LDH), and interleukin-1ß (IL-1ß) assays, and muscle was removed for inflammasome activation immunoblotting and qRT-PCR expression for nucleotide and oligomerization domain, leucine-rich repeat-containing protein family, pyrin-containing domain 3 receptor (NLRP3) inflammasome components. RESULTS: BthTX-I-induced inflammation and myonecrosis, shown by intravital microscope, and LDH and CK release, respectively. Mouse treatment with A438079, a P2X7 receptor antagonist, did not modify these effects. BthTX-I induced inflammasome activation in muscle, but P2X7R participation in this effect was not observed. CONCLUSION: Together, the results showed for the first time that BthTX-I in gastrocnemius muscle induces inflammation and consequently, inflammasome activation via NLRP3 with caspase-1 activation and IL-1ß liberation.

Effect of Bothrops bilineata snake venom on neutrophil function.

The aim of the study was to evaluate the in vitro effects of Bothrops bilineata crude venom (BbV) on isolated human neutrophil function. We proved that BbV isn't toxic towards human neutrophils. During an incubation of human neutrophils with BbV hydrogen peroxide was produced. Moreover, BbV was able to stimulate neutrophil release of proinflammatory mediators such as IL-8 and IL-6 as well as PGE2 and NETs liberation. There is no data in the literature showing the effect of BbV on the production of IL-6 and IL-8 or NETs liberation by isolated human neutrophils. Taken together our results testify that BbV triggers relevant proinflammatory events in human neutrophils.