Effect of Lonomia obliqua Venom on Human Neutrophils.

The significant incidence of deforestation in South America culminates in the contact of humans with typical forests species. Among these species, one may highlight Lonomia obliqua caterpillar, which, when touched by humans, can poison them through their bristles. Therefore, better acknowledging the mechanisms involved in envenomation caused by Lonomia obliqua caterpillar bristle extract (LOCBE) may contribute to further treatments. Recently, we demonstrated that LOCBE induces a pro-inflammatory profile in endothelial cells; thus, we decided to investigate the effects of LOCBE on human polymorphonuclear neutrophils (PMN), which are the first leukocytes that migrate to the inflammatory focus. Our results showed that treatment with LOCBE induced PMN chemotaxis together with alterations in actin cytoskeleton and focal adhesion kinase (FAK) activation, favoring migration. Concurrently, LOCBE induced PMN adhesion to matrix proteins, such as collagen IV, fibronectin, and fibrinogen. Moreover, we observed that LOCBE attenuated PMN apoptosis and increased reactive oxygen species (ROS) production together with nuclear factor kB (NF-κB) activation-a redox-sensitive transcription factor-as well as interleukin (IL)-1ß and IL-8 release. We call attention to the ROS-dependent effect of LOCBE on increased cell migration once an antioxidant treatment reverted it. In summary, we report that LOCBE activates PMN, inducing pro-inflammatory responses modulated by ROS.

Analysis of Post-Sample Collection EDTA Effects on Mean Platelet Volume Values in Relation to Overweight and Obese Patient Status.

BACKGROUND: Mean platelet volume (MPV) may be a useful biomarker for platelet activation in obese patients. However, storage duration and use of anticoagulant K3-ethylenediaminetetraacetic acid (EDTA) may interfere with these measurements. OBJECTIVES: The aim of this study was to measure the variability of MPV in obese patients following exposure to EDTA. METHOD: A total of 160 patients were divided into 3 groups according to body mass index (BMI; normal: <25 kg/m2; overweight: 25-30 kg/m2; obese: >30 kg/m2). Blood was collected in sterile tubes containing K3-EDTA. Blood cell counts were obtained using the CELL-DYN Ruby system immediately and 1, 2, and 3 h after collection. RESULTS: MPV was found to be directly proportional to BMI. With the addition of EDTA, MPV was increased in the first hour after collection; MPV then decreased to levels that were lower than initial baseline measurements. CONCLUSIONS: K3-EDTA use alters platelet volume. The time from collection to measurement should be standardized to reduce MPV value variance. MPV should be determined within 1 h of collection to avoid anticoagulant use-related interference.

Effects of Lonomia obliqua Venom on Vascular Smooth Muscle Cells: Contribution of NADPH Oxidase-Derived Reactive Oxygen Species.

Envenomation caused by human contact with the caterpillar Lonomia is characterized by deleterious effects on coagulation and patency of blood vessels. The cellular effects induced by Lonomia obliqua venom highlights its capacity to activate endothelial cells, leading to a proinflammatory phenotype. Having more knowledge about the mechanisms involved in envenomation may contribute to better treatment. We aimed to evaluate the effects of Lonomia obliqua caterpillar bristle extract (LOCBE) on vascular smooth muscle cells (VSMC). We observed that LOCBE induced VSMC migration, which was preceded by alterations in actin cytoskeleton dynamics and Focal Adhesion Kinase activation. LOCBE also induced Extracellular Signal-Regulated Kinase (ERK) phosphorylation in VSMC, and the inhibition of this pathway impaired cell proliferation. Stimulation of VSMC with LOCBE triggered reactive oxygen species (ROS) production through the activation of NADPH oxidase. The rapid increase in these ROS further induced mitochondrial ROS production, however only NADPH oxidase-derived ROS were involved in ERK activation in VSMC. We that demonstrated the chemotactic and proliferative effects of LOCBE on VSMC were dependent on ROS production, mainly through NADPH oxidase. Together, the data show that Lonomia obliqua venom can interact with and activate VSMC. These effects rely on ROS production, suggesting new potential targets for treatment against vascular damage during envenomation.

Data in support of alpha1beta1 and integrin-linked kinase interact and modulate angiotensin II effects in vascular smooth muscle cells.

The data provides information in support of the research article Moraes et al., Atherosclerosis 243(2) (2015) 477-485 [1]. Here we provide data behind the mechanisms involved in Angiotensin II (Ang II) effects on vascular smooth muscle cells (VSMC). Ang II-induced VSMC ROS production is modulated by alpha1beta1 integrin. Ang II also stimulates ROS production in VSMC via p47 (phox) , a NOX2 subunit. Furthermore, Ang II effect on VSMC migration was also inhibited by NOX2 inhibitor. We showed that obtustatin, alpha1beta1 integrin blocker, inhibited Ang II effect on p47 (phox) activation. Ang II effect on ROS production is also PI3K dependent. Finally we showed that NOX1 and Integrin-Linked-Kinase (ILK) are crucial to NOX2 activation. The research provides information about the sequential events of NOX1/alpha1beta1 integrin/ILK/NOX2 in Ang II effects on VSMC.

Alpha1beta1 and integrin-linked kinase interact and modulate angiotensin II effects in vascular smooth muscle cells.

The effects of angiotensin II (Ang II) on vascular smooth muscle cells (VSMC) are modulated by reactive oxygen species (ROS) and also involve integrin engagement. However, the potential link between alpha1beta1 integrin signaling with NOX system and their combined contribution to Ang II effects on VSMC have not been investigated. We aimed to elucidate the moslecular mechanisms underlying the activation of these two pathways in Ang II effects on VSMC. Ang II-induced VSMC migration (2-fold increase) and proliferation (2.5-fold increase) is modulated by alpha1beta1 integrin, being inhibited by obtustatin, a specific alpha1beta1 integrin blocker. Ang II also stimulates ROS production in VSMC (140%) that is NOX1 dependent, being completely inhibited in NOX1 silenced cells. The ROS production develops in two peaks, and the second peak is maintained by NOX2 activation. Apocynin and obtustatin inhibit the NOX2-associated second peak, but not the first peak of ROS production, which is related to NOX1 activation. Corroborating the involvement of alpha1beta1 integrin, the pretreatment of VSMC with obtustatin impaired Ang II-induced FAK phosphorylation, AKT activation, p21 degradation and the increase of ILK expression. Silencing of ILK blocked cell migration, AKT phosphorylation and the second peak of ROS, but partially inhibits (70%) VSMC proliferation induced by Ang II. The data demonstrate a novel role for NOX2 in Ang II effects on VSMC, and suggest alpha1beta1 integrin and ILK as target molecules to the development of more effective therapeutic interventions in cardiovascular diseases.