Platelets Fuel the Inflammasome Activation of Innate Immune Cells

The inflammasomes control the bioactivity of pro-inflammatory cytokines of the interleukin (IL)-1 family. The inflammasome assembled by NLRP3 has been predominantly studied in homogeneous cell populations in vitro, neglecting the influence of cellular interactions that occur in vivo. Here, we show that platelets boost the inflammasome capacity of human macrophages and neutrophils and are critical for IL-1 production by monocytes. Platelets license NLRP3 transcription, thereby enhancing ASC oligomerization, caspase-1 activity, and IL-1β secretion. Platelets influence IL-1β production in vivo, and blood platelet counts correlate with plasmatic IL-1β levels in malaria. Furthermore, we reveal an enriched platelet gene signature among the highest-expressed transcripts in IL-1β-driven autoinflammatory diseases. The platelet effect is independent of cell-to-cell contact, platelet-derived lipid mediators, purines, nucleic acids, and a host of platelet cytokines, and it involves the triggering of calcium-sensing receptors on macrophages. Hence, platelets provide an additional layer of regulation of inflammasomes and IL-1-driven inflammation.

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Platelets license NLRP3 for inflammasome activattion in innate immune cells

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Platelets are required for optimal monocyte inflammasome activation

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Platelets shape IL-1β in vivo, and platelet counts correlate with IL-1β in plasma

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A constitutive, heat-sensitive soluble platelet-factor boost IL-1β in macrophages

Antinociceptive and anti-inflammatory activities of Copaifera pubiflora Benth oleoresin and its major metabolite ent-hardwickiic acid

ETHNOPHARMACOLOGICAL RELEVANCE

Copaifera species folkloric names are "copaíbas, copaibeiras, copaívas or oil stick", which are widely used in Brazilian folk medicine. Among all ethnopharmacological applications described for Copaifera spp oleoresins, their anti-inflammatory effect stands out. However, the knowledge of anti-inflammatory and antinociceptive properties of Copaifera pubiflora Benth is scarce.

AIM OF THE STUDY

To investigate the cytotoxic, anti-inflammatory, and antinociceptive activities of C. pubiflora oleoresin (CPO), and its major compound ent-hardwickiic acid (HA).

MATERIAL AND METHODS

The phosphatase assay was used to evaluate the cytotoxicity of CPO and HA in three different cell lines. CPO and HA doses of 1, 3, and 10 mg/kg were employed in the biological assays. The assessment of motor activity was performed using open-field and rotarod tests. Anti-inflammatory activity of CPO and HA was assessed through luciferase assay, measurement of INF-γ, IL-1β, IL-6, IL-10, and TNF-α in a multi-spot system with the immortalized cell line THP-1, zymosan-induced arthritis, and carrageenan-induced paw edema. Acetic acid-induced abdominal writhing and formalin tests were undertaken to evaluate the antinociceptive potential of CPO and HA. In addition, the evaluation using carrageenan was performed to investigate the effect of CPO in pain intensity to a mechanical stimulus (mechanical hyperalgesia), using the von Frey filaments. A tail-flick test was used to evaluate possible central CPO and HA actions.

RESULTS

In the cytotoxicity evaluation, CPO and HA were not cytotoxic to the cell lines tested. CPO and HA (10 mg/kg) did not affect animals' locomotor capacity in both open-field and rotarod tests. In the luciferase assay, CPO and HA significantly reduced luciferase activity (p < 0.05). This reduction indicates a decrease in NF-κB activity. HA and CPO decreased INF-γ, IL-1β, IL-6, IL-10, and TNF-α at 24 and 72 h in the multi-spot system. In zymosan-induced arthritis, CPO and HA decreased the number of neutrophils in the joint of arthritic mice and the number of total leukocytes (p < 0.05). In experimental arthritis HA significantly decreased joint swelling (p < 0.05). CPO and HA also increased the mechanical threshold during experimental arthritis. HA and CPO significantly inhibited the carrageenan-induced paw edema, being the doses of 10 mg/kg the most effective, registering maximum inhibitions of 58 ± 8% and 76 ± 6% respectively, p < 0.05. CPO and HA reduced the nociceptive behavior in both phases of formalin at all tested doses. The highest doses tested displayed inhibitions of 87 ± 1% and 72 ± 4%, respectively, p < 0.001, in the first phase, and 87 ± 1% and 81 ± 2%, respectively, p < 0.001, in the second phase. Oral treatment of CPO and HA (1, 3, 10 mg/kg) significantly reduced the nociceptive response in acetic acid-induced abdominal writhings, and the 10 mg/kg dose was the most effective with maximum inhibitions of 86 ± 2% and 82 ± 1%, respectively, p < 0.001. Both HA and CPO significantly decreased the intensity of mechanical inflammatory hyper-nociception on carrageenan-induced hyperalgesia at all tested doses, and 10 mg/kg was the most effective dose with maximum inhibitions of 73 ± 5% and 74 ± 7%, respectively, p < 0.05.CPO increased the tail-flick latencies in mice, and concomitant administration of naloxone partially reduced its effect.

CONCLUSIONS

CPO and HA may inhibit the production of inflammatory cytokines by suppressing the NF-κB signaling pathway, resulting in anti-inflammatory and antinociceptive activities.

Role of the route of leukotrienes in an experimental model of oral mucositis induced by 5-fluorouracil 1

PURPOSE

To investigate the participation of cysteinyl leukotrienes in the pathophysiology of oral mucositis.

METHODS

Oral mucositis was induced in hamsters using 5-fluorouracil (5-FU; 60 and 40 mg/kg; i.p., on days 1 and 2, respectively, and with excoriations in jugal mucosa on day 4). Montelukast (10, 20, or 40 mg/kg/d; gavage), MK886 (3 mg/kg/d, i.p.), or saline or celecoxib (7.5 mg/kg/d; i.p.) was administered 1 h prior to 5-FU and daily, until the fourth (MK886) or tenth day, when the animals were euthanized and their jugal mucosa was collected for macroscopic, histopathological, and immunohistochemical evaluation.

RESULTS

Neither montelukast nor MK-886 prevented the oral mucositis induced by 5-FU, as observed by histopathological evaluation. In addition, we did not find significant differences in the expression of inducible nitric oxide synthase-2, cyclooxygenase-2, or interleukin (IL)-1β between the experimental and control groups. However, we did observe a significant decrease in tumor necrosis factor (TNF)-α expression for all doses of montelukast; we also observed a significant decrease in IL-10 with 40 mg/kg/d and MK 886.

CONCLUSIONS

Cysteinyl leukotrienes do not play an important role in experimental oral mucositis induced by 5-FU. There is a modulating action specifically on TNF-α.

Stable experimental model of carotid artery saccular aneurysm in swine using the internal jugular vein

OBJECTIVE

To develop an experimental model of stable saccular aneurysm in carotid of pigs using the internal jugular vein.

METHODS

In 12 healthy pigs, weighing between 25 and 5 0kg, five males and seven females, we made a right common carotid artery aneurysm. After elliptical arteriotomy, we carried out a terminolateral anastomosis with the distal stump of the internal jugular vein. Aneurysm volume was calculated so that the value did not exceed 27 times the area of the arteriotomy. After six days angiography and microscopic examination were performed to assess patency of the aneurysm and the presence of total or partial thrombosis.

RESULTS

There was a significant weight gain of pigs in the time interval between the manufacture of the aneurysm and angiography (p = 0.04). Aneurysmal patency was observed in ten pigs (83%). Operative wound infections occurred in two animals (16.6%), both with early onset, three days after the making of the aneurysm. Histological analysis showed aneurysm thrombus partially occluding the light in nine pigs (75%). In these animals, it was observed that on average 9% of the aneurysmal diameter was filled with thrombi.

CONCLUSION

It was possible to develop a stable experimental model of saccular aneurysms in pig carotid artery by use of the internal jugular vein.

Mango tree pruning hay in substitution of elephant grass in cattle diet

This experiment was conducted to evaluate the effect of different levels of substitution (0, 33.3, 66.7, and 100 %) of elephant grass by hay of mango tree pruning (HMTP) on intake and digestibility in cattle and on the in vitro gas production. Moreover, the effect of tannin in HMTP on the gas production and in vitro degradability of the dry matter was evaluated, using polyethylene glycol (PEG). The intake and digestibility were evaluated in a double 4 × 4 square Latin design, using eight Holstein intact bulls. To evaluate the gas production and degradability, in vitro semi-automated gas production technique was used. The substitution of elephant grass by HMTP decreased the intake (P<0.05) and the digestibility (P<0.05) of the nutrients and also the gas production (P<0.05). Furthermore, the utilization of PEG as a tannin-complexing agent increased the gas production and degradability of the HMTP (P<0.05). It was concluded that the high cell wall lignification and the presence of tannin limit the use of HMTP as the only source of roughage in cattle diets.

Biometria da cabeça e da cavidade craniana de ovinos deslanados sem raça definida (Ovis aries LINNAEUS, 1758) em Petrolina/Pernambuco, Brasil

A espécie ovina é largamente utilizada na região Nordeste do Brasil por apresentar alta rusticidade. No entanto, sua anatomia ainda é pouco estudada. Assim, crescem os estudos para gerar subsídios técnico-científicos àqueles profissionais que trabalham com as áreas aplicadas da Medicina Veterinária e afins. O objetivo do presente estudo foi estabelecer correlações entre as dimensões da cabeça e da cavidade craniana, utilizando 80 ovinos, 40 machos e 40 fêmeas, com média de peso entre 27,0 e 33,0 kg. Em fêmeas, foi observada correlação entre a massa corpórea e o comprimento da cabeça; entre a massa corpórea e largura da cabeça; entre o comprimento da cabeça e sua respectiva largura; entre comprimento da cabeça e o comprimento da cavidade craniana e entre a altura da cabeça e o comprimento da cavidade craniana. As demais dimensões, nas fêmeas, não tiveram correlação estatisticamente significativa. Já em animais do sexo masculino, foi possível evidenciar correlação apenas entre a altura da cabeça e altura da cavidade craniana. Desta forma, é possível concluir que, quanto maiores forem as proporções da cabeça, maiores serão as dimensões e volume intracranianos.