PKC-α is involved in the signaling of phagocytosis induced by two snake venom secretory PLA2S in macrophages

Phagocytosis, an essential process for host defense, requires the coordination of a variety of signaling reactions. MT-II, an enzymatically inactive Lys49 phospholipase A2 (PLA2) homolog, and MT-III, a catalytically-active Asp49 PLA2, are known to activate phagocytosis in macrophages. In this study, the signaling pathways mediating phagocytosis, focusing on protein kinases, were investigated. Macrophages from male Swiss mice peritoneum were obtained 96 h after intraperitoneal thioglycolate injection. Phagocytosis was evaluated using nonopsonized zymosan particles in the presence or absence of specific inhibitors, as well as PKC and PKC-α localization by confocal microscopy. Moreover, protein kinase C (PKC) activity was assessed by γP32 ATP in macrophages stimulated by both PLA2s. Data showed that both sPLA2s increased phagocytosis. Cytochalasin D, staurosporine/H7, wortmannin, and herbimycin, inhibitors of actin polymerization, PKC, phosphoinositide 3-kinase (PI3K), and protein tyrosine kinase (PTK), respectively, significantly reduced phagocytosis induced by both PLA2s. PKC activity was increased in macrophages stimulated by both PLA2s. Actin polymerization and talin were evidenced by immunofluorescence and talin was recruited 5 min after both PLA2s stimulation. PKC and PKC-α localization within the cell were increased after 60 min of MT-II and MT-III stimulation. These data suggest that the effect of both PLA2s depends on actin cytoskeleton rearrangements and the activation of PKC, PI3K, and PTK signaling events required for phagocytosis.

Role of nitric oxide and signaling pathways modulating the stimulatory effect of snake venom secretory PLA2S on non-opsonized zymosan phagocytosis by macrophages

The phagocytic activity of macrophages activated with MT-II, a Lys-49 PLA2 homolog, and MT-III, an Asp-49 PLA2, from Bothrops asper snake venom, was investigated in this study using a pharmacological approach. Stimulating thioglycollate-elicited macrophages with both venom components enhanced their ability to phagocytose non-opsonized zymosan particles. MT-II and MT–III–induced phagocytosis was drastically inhibited by pretreating cells with L-NAME, aminoguanidine or L-NIL, cNOS or iNOS inhibitors, or with ODQ (sGC inhibitor) or Rp-cGMPS (PKG inhibitor). These results indicate that the NO/sGC/GMP/PKG pathway plays an essential role in the β-glucan-mediated phagocytosis induced in macrophages by these venom-secretory PLA2s.

Toxicological, enzymatic, and immunochemical characterization of Bothrops asper (Serpentes: Viperidae) reference venom from Panama / Caracterización toxicológica, enzimática e inmunoquímica del veneno de referencia de Bothrops asper (Serpentes: Viperidae) de Panamá

Introduction: It is estimated that 2 000 snakebites occur in Panama every year, 70 % of which are inflicted by Bothrops asper. Objective: To determine the biochemical and toxicologic effects and to assess the immunochemical characteristics of a reference pool of B. asper venom representative of Panama. Methods: The reference venom was prepared as a homogeneous mixture of the venoms obtained from 78 adult snakes collected in four geographic areas of Panama. Enzymatic and toxicological activities were assessed. The electrophoretic pattern was studied by SDS-PAGE. Immunoreactivity of various antivenoms was analyzed by Western blot. Results: B. asper reference venom has lethal, hemorrhagic, myotoxic, edema-forming, coagulant, defibrinating, proteinase and phospholipase A2 activities. SDS-PAGE showed the presence of protein bands with molecular weights ranging from 8 to 70 kDa, with the presence of predominant bands at ≈ 15 kDa and ≈ 30 to 66 kDa, which likely correspond to phospholipases A2 and metalloproteinases, respectively. Immunoblotting showed a high degree of recognition by various antivenoms, especially by antivenoms from Colombia and Costa Rica. Conclusions: Following recommendations by the World Health Organization, this reference venom of B. asper of Panama will become a useful tool for the preclinical evaluation of antivenoms distributed in this country.

Introducción: Se estima que 2 000 mordeduras de serpiente ocurren en Panamá cada año, el 70 % de las cuales son infligidas por Bothrops asper. Objetivo: Determinar los efectos bioquímicos y toxicológicos y evaluar las características inmunoquímicas del veneno de referencia de B. asper representativo de Panamá. Métodos: El veneno de referencia se preparó como una mezcla homogénea de los venenos obtenidos de 78 serpientes adultas recolectadas en cuatro áreas geográficas de Panamá. Se evaluaron las actividades enzimáticas y toxicológicas. El patrón electroforético se estudió mediante SDS-PAGE. La inmunoreactividad de varios antivenenos se analizó mediante transferencia de Western. Resultados: El veneno de referencia de B. asper tiene actividades letales, hemorrágicas, miotóxicas, formadoras de edema, coagulantes, desfibrinante, proteolítica y de fosfolipasa A2. El análisis de SDS-PAGE mostró la presencia de bandas de proteínas con pesos moleculares que varían de 8 a 70 kDa, con la presencia de bandas predominantes a ≈ 15 kDa y ≈ 30 a 66 kDa, que probablemente corresponden a fosfolipasas A2 y metaloproteinasas, respectivamente. La inmunotransferencia mostró un alto grado de reconocimiento por varios antivenenos, especialmente por antivenenos de Colombia y de Costa Rica. Conclusiones: Siguiendo las recomendaciones de la Organización Mundial de la Salud, este veneno de referencia de B. asper de Panamá se convertirá en una herramienta útil para la evaluación preclínica de antivenenos distribuidos en este país.

Instituto Butantan and Instituto Clodomiro Picado: a long-standing partnership in science, technology, and public health

Instituto Butantan (São Paulo, Brazil) and Instituto Clodomiro Picado (San José, Costa Rica) are public institutions devoted to scientific and technological research, production of antivenoms and other immunobiologicals, and a variety of public health interventions aimed at confronting the problem of snakebite envenoming in their countries and elsewhere. In the context of the 120th anniversary of Instituto Butantan, this work describes the historical developments in the relationship between these institutions, which has evolved into a solid cooperation platform in science, technology, and public health. The relationship between Instituto Butantan and Costa Rica started early in the 20th century, with the provision of Brazilian antivenoms to Costa Rica through the coordination of Instituto Butantan and the health system of Costa Rica, with the leadership of Clodomiro Picado Twight. After the decade of 1980, a prolific collaborative network has been established between Instituto Butantan and Instituto Clodomiro Picado (founded in 1970) in the areas of scientific and technological research in pharmacology, biochemistry, experimental pathology, immunology, and public health, as well as in antivenom development, production, preclinical evaluation, and quality control. In addition, both institutions have played a key role in the integration of regional efforts in Latin America to create a network of public institutions devoted to antivenom production and quality control, in close coordination with the Pan American Health Organization (PAHO). This long-standing partnership is an example of a highly productive south-south cooperation under a frame of solidarity and public well-being.

Appraisal of antivenom production in public laboratories in Latin America during the first semester of 2020: the impact of COVID-19

One of the 4 pillars of the World Health Organization (WHO) strategy for the prevention and control of snake bite envenomings is to ensure safe and effective pharmacotherapeutic treatments [1]. The mainstay in the pharmacotherapy of these envenomings, as well as of envenomings by scorpions and spiders, is the timely administration of safe and effective antivenoms [2,3]. Antivenoms are composed of immunoglobulins, or immunoglobulin fragments, purified from the plasma of animals, usually horses, immunized with venoms. Currently, there is an urgent need to improve antivenom availability, accessibility, and affordability on a global basis, particularly for use in sub-Saharan Africa, Asia, and Latin America [1]. There is a long tradition in snake, scorpion, spider, and, more recently, caterpillar antivenoms production in Latin America, especially centered in public manufacturing laboratories in Argentina, Brazil, Peru, Bolivia, Ecuador, Colombia, Venezuela, Costa Rica, and Mexico [4–6]. A network of public laboratories devoted to the production and quality control of antivenoms was established in this region in the last decade [4,5], which has recently led to the creation of the Latin American Network of Public Antivenom Manufacturing Laboratories (RELAPA, Red Latinoamericana de Laboratorios Públicos Productores de Antivenenos) [6]. RELAPA aims at consolidating governance mechanisms within a regional platform for technical cooperation, technology transfer, research, and training for the regional improvement of antivenom availability, under the coordination of the Pan American Health Organization (PAHO) and its office Centro Panamericano de Fiebre Aftosa (Panaftosa). As part of the ongoing activities of RELAPA, a survey was sent by PAHO/Panaftosa to the institutions integrating this network to assess the situation of antivenom manufacture in these laboratories during the period January 2020 to July 2020, with the goal of analyzing in which ways has antivenom production been affected in this extraordinary year, especially regarding the impact of the Coronavirus Disease 2019 (COVID-19) pandemic, which has profoundly stricken Latin America [7]. The survey was sent to the directors of the institutions of RELAPA (the list of institutions is detailed in Fan and colleagues [6]). The survey included the following aspects: (a) What was the demand and the production of antivenoms (including snake, scorpion, spider, and caterpillar antivenoms) during the period January 2020 to July 2020? (b) What was the effect of the COVID-19 pandemic in (i) the number of professional and technical staff working to manufacture antivenom, (ii) acquisitions of consumables and laboratory equipment, (iii) overall budget devoted to antivenom manufacture, and (iv) attention to the COVID-19 crisis in terms of development of therapeutic equine preparations against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), preparation of diagnostic reagents, quality control activities, or assignment of staff to attend other pandemic issues? (c) Which are the priorities of the laboratories in the near future regarding regional cooperation in the field of antivenom manufacture and quality control? The survey was carried out between October 1 and October 19, 2020, using the platform Qualtrics (Qualtrics XM Platform, Seattle, Washington, United States of America).

Envenenamiento ofídico en Costa Rica: logros y tareas pendientes / Snakebite envenoming in Costa Rica: achievements and pending tasks

Resumen Objetivo: Efectuar un análisis de los logros en Costa Rica en cuanto al problema de los envenenamientos por mordeduras de serpientes, y señalar tareas pendientes para reducir aún más el impacto de esta patología. Metodología: Se efectuó una revisión de bibliografía relacionada con el estudio del envenenamiento ofídico en Costa Rica y con los avances efectuados en el tema, en el país. Paralelamente, se identificaron aspectos que requieren atención en el manejo de esta enfermedad tropical desatendida. Conclusiones: Desde las primeras décadas del siglo XX, se han realizado avances significativos en la comprensión y manejo del problema de los envenenamientos por mordedura de serpiente en Costa Rica. Se ha trabajado desde una visión integral que incluye: investigación científico-tecnológica, producción y distribución de antivenenos, esfuerzos en prevención, capacitación de las personas profesionales de la salud en el diagnóstico y tratamiento, y docencia de grado y posgrado en el tema. El país ha asumido un papel de liderazgo a nivel internacional, tanto en el plano académico como en la provisión de antivenenos a muchos países. No obstante, aún quedan aspectos del problema que requieren nuevos esfuerzos en nuestro medio, sobre todo en lo referente a la atención de las consecuencias biomédicas, psicológicas, sociales y económicas que sufren las personas afectadas.

Abstract Aim: To analyze the achievements made in Costa Rica in confronting the problem of snakebite envenomings, and to identify pending tasks to further reduce the impact of this pathology. Methods: A review of the literature on snakebite envenomings in Costa Rica was carried out, identifying the main achievements reached in the country. In parallel, issues that require renewed attention in the management of this neglected tropical disease were identified. Conclusions: Since the first decades of the 20th century, significant advances have been made in Costa Rica for understanding and confronting the problem of snakebite envenomings. An integrative perspective has been implemented, which includes scientific and technological research, production and distribution of antivenoms, prevention campaigns, training of health professionals in the diagnosis and treatment of envenomings, and teaching at graduate and undergraduate levels. Costa Rica has had a leading international role in this topic at the academic level, and by providing antivenoms to many countries. Nevertheless, there are issues that require further efforts, especially regarding the attention to the biomedical, psychological, social and economic consequences suffered by people affected by snakebites.

Antibiotic therapy for snakebite envenoming

There are numerous conflicting recommendations available on the use of antibiotics following snakebite. The present letter to the editor presents some recommendations based on recent studies, and aims to stimulate debate on this topic.(AU)

12-HETE is a regulator of PGE2 production via COX-2 expression induced by a snake venom group IIA phospholipase A2 in isolated peritoneal macrophages

The snake venom miotoxin (MT)-III is a group IIA secreted phospholipase A2 (sPLA2) with pro-inflammatory activities. Previous studies have demonstrated that MT-III has the ability to stimulate macrophages to release inflammatory lipid mediators derived from arachidonic acid metabolism. Among them, we highlight prostaglandin (PG)E2 produced by the cyclooxygenase (COX)-2 pathway, through activation of nuclear factor (NF)-capaB. However, the mechanisms coordinating this process are not fully understood. This study investigates the regulatory mechanisms exerted by other groups of bioactive eicosanoids derived from 12-lipoxygenase (12-LO), in particular 12-hydroxyeicosatetraenoic (12-HETE), on group IIA sPLA2-induced (i) PGE2 release, (ii) COX-2 expression, and (iii) activation of signaling pathways p38 mitogen-activated protein kinases(p38MAPK), protein C kinase (PKC), extracellular signal-regulated kinase 1/2 (ERK1/2), and NF-?B. Stimulation of macrophages with group IIA sPLA2 resulted in release of 12-HETE without modification of 12-LO protein levels. Pre-treatment of these cells with baicalein, a 12-LO inhibitor, decreased the sPLA2-induced PGE2 production, significantly reduced COX-2 expression, and inhibited sPLA2-induced ERK; however, it did not affect p38MAPK or PKC phosphorylation. In turn, sPLA2-induced PGE2 release and COX-2 expression, but not NF-capaB activation, was attenuated by pre-treating macrophages with PD98059 an inhibitor of ERK1/2. These results suggest that, in macrophages, group IIA sPLA2-induced PGE2 release and COX-2 protein expression are distinctly mediated through 12-HETE followed by ERK1/2 pathway activation, independently of NF-?B activation. These findings highlight an as yet undescribed mechanism by which 12-HETE regulates one of the distinct signaling pathways for snake venom group IIA sPLA2-induced PGE2 release and COX-2 expression in macrophages.

"Bad things come in small packages": predicting venom-induced coagulopathy in Bothrops atrox bites using snake ontogenetic parameters

Introduction: Snake venom composition shows significant inter- and intra-species variation. In the case of the viperid species Bothrops atrox, responsible for the majority of snakebites in the Amazon region, geographical and ontogenetic variables affect venom composition, with ecological and medical implications. Previous studies had shown that venom from neonate and juvenile Bothrops specimens have a higher in vitro coagulant activity. The aim of this investigation was to assess the association of clinical outcomes, such as venom-induced coagulopathy and local complications, with B. atrox ontogenetic variables. Methods: This study explored the relationship between some clinical parameters in patients suffering envenomations by B. atrox in the Amazon and several morphometric parameters of the snake specimens causing the bites.Results: There were 248 specimens confirmed as agents of envenomation, mostly female snakes (70.5%) and classified as juveniles (62.7%). Patients bitten by neonates compared to adult snakes [OR=2.70 (95%CI 1.15-6.37); p=.021] and by snakes with white tail tip [OR=1.98 (95%CI 1.15–3.41); p=.013] were more likely to develop coagulopathy. Time from patient admission to the unclottable blood reversion was not affected by the snake gender (p=.214) or age (p=.254). Patients bitten by neonate (p=.024) or juvenile snakes (p<.0001) presented a lower frequency of moderate to severe edema, as compared to those bitten by adult snakes. In agreement with experimental observations, patients bitten by neonates and by snakes with a white tail tip were more likely to develop coagulopathy than those bitten by adult snakes. In contrast, envenomations by adult snakes were associated with a higher incidence of severe local edema. Conclusion: Despite these variations, no difference was observed in the time needed to recover blood clotting in these patients after Bothrops antivenom administration.

12-HETE is a regulator of PGE2 production via COX-2 expression induced by a snake venom group IIA phospholipase A2 in isolated peritoneal macrophages

The snake venom miotoxin (MT)-III is a group IIA secreted phospholipase A2 (sPLA2) with pro-inflammatory activities. Previous studies have demonstrated that MT-III has the ability to stimulate macrophages to release inflammatory lipid mediators derived from arachidonic acid metabolism. Among them, we highlight prostaglandin (PG)E2 produced by the cyclooxygenase (COX)-2 pathway, through activation of nuclear factor (NF)-capaB. However, the mechanisms coordinating this process are not fully understood. This study investigates the regulatory mechanisms exerted by other groups of bioactive eicosanoids derived from 12-lipoxygenase (12-LO), in particular 12-hydroxyeicosatetraenoic (12-HETE), on group IIA sPLA2-induced (i) PGE2 release, (ii) COX-2 expression, and (iii) activation of signaling pathways p38 mitogen-activated protein kinases(p38MAPK), protein C kinase (PKC), extracellular signal-regulated kinase 1/2 (ERK1/2), and NF-?B. Stimulation of macrophages with group IIA sPLA2 resulted in release of 12-HETE without modification of 12-LO protein levels. Pre-treatment of these cells with baicalein, a 12-LO inhibitor, decreased the sPLA2-induced PGE2 production, significantly reduced COX-2 expression, and inhibited sPLA2-induced ERK; however, it did not affect p38MAPK or PKC phosphorylation. In turn, sPLA2-induced PGE2 release and COX-2 expression, but not NF-capaB activation, was attenuated by pre-treating macrophages with PD98059 an inhibitor of ERK1/2. These results suggest that, in macrophages, group IIA sPLA2-induced PGE2 release and COX-2 protein expression are distinctly mediated through 12-HETE followed by ERK1/2 pathway activation, independently of NF-?B activation. These findings highlight an as yet undescribed mechanism by which 12-HETE regulates one of the distinct signaling pathways for snake venom group IIA sPLA2-induced PGE2 release and COX-2 expression in macrophages.

Bad things come in small packages: predicting venom-induced coagulopathy in Bothrops atrox bites using snake ontogenetic parameters

Introduction: Snake venom composition shows significant inter- and intra-species variation. In the case of the viperid species Bothrops atrox, responsible for the majority of snakebites in the Amazon region, geographical and ontogenetic variables affect venom composition, with ecological and medical implications. Previous studies had shown that venom from neonate and juvenile Bothrops specimens have a higher in vitro coagulant activity. The aim of this investigation was to assess the association of clinical outcomes, such as venom-induced coagulopathy and local complications, with B. atrox ontogenetic variables. Methods: This study explored the relationship between some clinical parameters in patients suffering envenomations by B. atrox in the Amazon and several morphometric parameters of the snake specimens causing the bites.Results: There were 248 specimens confirmed as agents of envenomation, mostly female snakes (70.5%) and classified as juveniles (62.7%). Patients bitten by neonates compared to adult snakes [OR=2.70 (95%CI 1.15-6.37); p=.021] and by snakes with white tail tip [OR=1.98 (95%CI 1.15–3.41); p=.013] were more likely to develop coagulopathy. Time from patient admission to the unclottable blood reversion was not affected by the snake gender (p=.214) or age (p=.254). Patients bitten by neonate (p=.024) or juvenile snakes (p<.0001) presented a lower frequency of moderate to severe edema, as compared to those bitten by adult snakes. In agreement with experimental observations, patients bitten by neonates and by snakes with a white tail tip were more likely to develop coagulopathy than those bitten by adult snakes. In contrast, envenomations by adult snakes were associated with a higher incidence of severe local edema. Conclusion: Despite these variations, no difference was observed in the time needed to recover blood clotting in these patients after Bothrops antivenom administration.

Situación de los laboratorios públicos productores de antivenenos en América Latina / Situation of public laboratories manufacturing antivenoms in Latin America

The situation of public laboratories manufacturing antivenoms in Latin America was analyzed, based on the results of a workshop coordinated by the Pan American Foot-and-Mouth Disease Center (PANAFTOSA) of the Pan American Health Organization (PAHO). Nine countries in the region have 12 public laboratories that produce and distribute antivenoms for use against different venomous animals. The situation of each laboratory was discussed, and an analysis was conducted of the current scenario, which is characterized by increasing regulatory requirements that vary in terms of infrastructure and production capacity. The authors identified a need to organize regional cooperation processes to improve the availability of antivenoms, including: research and development projects to improve processes and technologies; studies of the capacity of antivenoms to neutralize different poisons; and technical training programs for professionals and technical personnel. In the current context, in which the World Health Organization has prepared a global strategy for the prevention and control of snakebite envenoming, PANAFTOSA has taken on coordination of this initiative in the Americas. Improving the availability of antivenoms is the priority. As a result of the workshop, the RELAPA network was created, bringing together public laboratories that manufacture antivenoms in Latin America, in order to strengthen these laboratories and increase the availability of, and access to effective and safe antivenoms throughout Latin America.

Perspectives and recommendations towards evidence-based health care for scorpion sting envenoming in the Brazilian Amazon: a comprehensive review

Although underreported across the Amazon region, scorpion stings are very prevalent in some areas and can be potentially life-threatening, especially in children. The most vulnerable populations are those living in locations far from the capitals, hence having limited access to the health system where the appropriate structure for the treatment of severe cases is found. An abundant and diverse fauna of scorpions is found in the region, but few studies have been conducted to decipher the clinical characteristics and therapeutic response of the available antivenoms in envenomings caused by the various species. Antivenom underdosage as well as delayed medical assistance are common among indigenous populations, resulting in poor outcome rates. An in depth understanding of the epidemiological, clinical and therapeutic aspects of scorpion sting envenomings in the Amazon is necessary to improve the outcome of these cases.

Situación de los laboratorios públicos productores de antivenenos en América Latina / Situation of public laboratories manufacturing antivenoms in Latin America

The situation of public laboratories manufacturing antivenoms in Latin America was analyzed, based on the results of a workshop coordinated by the Pan American Foot-and-Mouth Disease Center (PANAFTOSA) of the Pan American Health Organization (PAHO). Nine countries in the region have 12 public laboratories that produce and distribute antivenoms for use against different venomous animals. The situation of each laboratory was discussed, and an analysis was conducted of the current scenario, which is characterized by increasing regulatory requirements that vary in terms of infrastructure and production capacity. The authors identified a need to organize regional cooperation processes to improve the availability of antivenoms, including: research and development projects to improve processes and technologies; studies of the capacity of antivenoms to neutralize different poisons; and technical training programs for professionals and technical personnel. In the current context, in which the World Health Organization has prepared a global strategy for the prevention and control of snakebite envenoming, PANAFTOSA has taken on coordination of this initiative in the Americas. Improving the availability of antivenoms is the priority. As a result of the workshop, the RELAPA network was created, bringing together public laboratories that manufacture antivenoms in Latin America, in order to strengthen these laboratories and increase the availability of, and access to effective and safe antivenoms throughout Latin America.

Perspectives and recommendations towards evidence-based health care for scorpion sting envenoming in the Brazilian Amazon: a comprehensive review

Although underreported across the Amazon region, scorpion stings are very prevalent in some areas and can be potentially life-threatening, especially in children. The most vulnerable populations are those living in locations far from the capitals, hence having limited access to the health system where the appropriate structure for the treatment of severe cases is found. An abundant and diverse fauna of scorpions is found in the region, but few studies have been conducted to decipher the clinical characteristics and therapeutic response of the available antivenoms in envenomings caused by the various species. Antivenom underdosage as well as delayed medical assistance are common among indigenous populations, resulting in poor outcome rates. An in depth understanding of the epidemiological, clinical and therapeutic aspects of scorpion sting envenomings in the Amazon is necessary to improve the outcome of these cases.

Improving the control of snakebite envenomation in Latin America and the Caribbean: a discussion on pending issues

Snakebite envenomations represent a public health problem of great impact, especially in sub-Saharan Africa, Asia, Latin America and some regions of Oceania.1 They predominantly affect people living in impoverished rural agricultural settings. Historically snakebite has received little attention from health authorities, research agendas, pharmaceutical companies and health advocacy groups. However, a growing awareness of the seriousness of these envenomations has developed in recent years. The World Health Organization (WHO) incorporated snakebite envenomation as a category A disease in its list of neglected tropical diseases and is developing an integrated global road map to confront it. Moreover, a resolution was adopted in May 2018 by the 71st World Health Assembly that gives WHO a strong mandate to develop comprehensive actions for improving the prevention and management of these envenomations on a global scale.2 In Latin America and the Caribbean, the Pan American Health Organization (PAHO) is building a regional plan to confront this neglected disease. The main pending issues to deal with snakebite envenomation in this region are discussed in this editorial, with the aim of highlighting areas where urgent actions are required.

A snake venom-secreted phospholipase A2 induces foam cell formation depending on the activation of factors involved in lipid homeostasis

MT-III, a snake venom GIIA sPLA(2), which shares structural and functional features with mammalian GIIA sPLA(2)s, activates macrophage defense functions including lipid droplet (LDs) formation, organelle involved in both lipid metabolism and inflammatory processes. Macrophages (M Phi s) loaded with LDs, termed foam cells, characterize early blood vessel fatty-streak lesions during atherosclerosis. However, the factors involved in foam cell formation induced by a GIIA sPLA(2) are still unknown. Here, we investigated the participation of lipid homeostasis-related factors in LD formation induced by MT-III in macrophages. We found that MT-III activated PPAR-gamma and PPAR-beta/delta and increased the protein levels of both transcription factors and CD36 in macrophages. Pharmacological interventions evidenced that PPAR-gamma, PPAR-beta/delta, and CD36 as well as the endoplasmic reticulum enzymes ACAT and DGAT are essential for LD formation. Moreover, PPAR-beta/delta, but not PPAR-gamma, is involved in MT-III-induced PLIN2 protein expression, and both PPAR-beta/delta and PPAR-gamma upregulated CD36 protein expression, which contributes to MT-III-induced COX-2 expression. Furthermore, production of 15-d-PGJ2, an activator of PPARs, induced by MT-III, was dependent on COX-1 being LDs an important platform for generation of this mediator.