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1.
BMC Genomics ; 22(1): 639, 2021 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-34479486

RESUMO

BACKGROUND: Resistance of pest insect species to insecticides, including B. thuringiensis (Bt) pesticidal proteins expressed by transgenic plants, is a threat to global food security. Despite the western corn rootworm, Diabrotica virgifera virgifera, being a major pest of maize and having populations showing increasing levels of resistance to hybrids expressing Bt pesticidal proteins, the cell mechanisms leading to mortality are not fully understood. RESULTS: Twenty unique RNA-seq libraries from the Bt susceptible D. v. virgifera inbred line Ped12, representing all growth stages and a range of different adult and larval exposures, were assembled into a reference transcriptome. Ten-day exposures of Ped12 larvae to transgenic Bt Cry3Bb1 and Gpp34/Tpp35Ab1 maize roots showed significant differential expression of 1055 and 1374 transcripts, respectively, compared to cohorts on non-Bt maize. Among these, 696 were differentially expressed in both Cry3Bb1 and Gpp34/Tpp35Ab1 maize exposures. Differentially-expressed transcripts encoded protein domains putatively involved in detoxification, metabolism, binding, and transport, were, in part, shared among transcripts that changed significantly following exposures to the entomopathogens Heterorhabditis bacteriophora and Metarhizium anisopliae. Differentially expressed transcripts in common between Bt and entomopathogen treatments encode proteins in general stress response pathways, including putative Bt binding receptors from the ATP binding cassette transporter superfamily. Putative caspases, pro- and anti-apoptotic factors, as well as endoplasmic reticulum (ER) stress-response factors were identified among transcripts uniquely up-regulated following exposure to either Bt protein. CONCLUSIONS: Our study suggests that the up-regulation of genes involved in ER stress management and apoptotic progression may be important in determining cell fate following exposure of susceptible D. v. virgifera larvae to Bt maize roots. This study provides novel insights into insect response to Bt intoxication, and a possible framework for future investigations of resistance mechanisms.


Assuntos
Bacillus thuringiensis , Besouros , Praguicidas , Animais , Bacillus thuringiensis/genética , Sobrevivência Celular , Besouros/genética , Endotoxinas/toxicidade , Resistência a Inseticidas , Larva/genética , Controle Biológico de Vetores , Plantas Geneticamente Modificadas/genética , Regulação para Cima , Zea mays/genética
2.
Ecotoxicol Environ Saf ; 225: 112721, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34478987

RESUMO

Previous studies reported adverse effects of genetically engineered maize that produces insecticidal Cry proteins from Bacillus thuringiensis (Bt) on the water flea Daphnia magna. In the current study, effects of flour, leaves, or pollen from stacked Bt maize that contains six Bt proteins (SmartStax) in two plant backgrounds on life table parameters of D. magna were investigated. Adverse effects were observed for Bt maize flour, originating from different production fields and years, but not for leaves or pollen, produced from plants grown concurrently in a glasshouse. Because leaves contained eight to ten times more Cry protein than flour, the effects of the flour were probably not caused by the Cry proteins, but by compositional differences between the plant backgrounds. Furthermore, considering the natural range of variation in the response of D. magna to conventional maize lines, the observed effects of Bt maize flour were unlikely to be of biological relevance. Our study demonstrates how Cry protein effects can be separated from plant background effects in non-target studies using Bt plant material as the test substance and how detected effects can be judged for their biological relevance.


Assuntos
Bacillus thuringiensis , Animais , Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Daphnia/genética , Endotoxinas/genética , Endotoxinas/toxicidade , Farinha , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/toxicidade , Plantas Geneticamente Modificadas , Zea mays/genética
3.
Int J Mol Sci ; 22(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34360923

RESUMO

The liver directly accepts blood from the gut and is, therefore, exposed to intestinal bacteria. Recent studies have demonstrated a relationship between gut bacteria and nonalcoholic fatty liver disease (NAFLD). Approximately 10-20% of NAFLD patients develop nonalcoholic steatohepatitis (NASH), and endotoxins produced by Gram-negative bacilli may be involved in NAFLD pathogenesis. NAFLD hyperendotoxicemia has intestinal and hepatic factors. The intestinal factors include impaired intestinal barrier function (leaky gut syndrome) and dysbiosis due to increased abundance of ethanol-producing bacteria, which can change endogenous alcohol concentrations. The hepatic factors include hyperleptinemia, which is associated with an excessive response to endotoxins, leading to intrahepatic inflammation and fibrosis. Clinically, the relationship between gut bacteria and NAFLD has been targeted in some randomized controlled trials of probiotics and other agents, but the results have been inconsistent. A recent randomized, placebo-controlled study explored the utility of lubiprostone, a treatment for constipation, in restoring intestinal barrier function and improving the outcomes of NAFLD patients, marking a new phase in the development of novel therapies targeting the intestinal barrier. This review summarizes recent data from studies in animal models and randomized clinical trials on the role of the gut-liver axis in NAFLD pathogenesis and progression.


Assuntos
Disbiose/microbiologia , Endotoxinas/toxicidade , Microbioma Gastrointestinal , Trato Gastrointestinal , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica , Animais , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/patologia , Humanos , Hepatopatia Gordurosa não Alcoólica/microbiologia , Hepatopatia Gordurosa não Alcoólica/patologia , Ensaios Clínicos Controlados Aleatórios como Assunto
4.
Ecotoxicol Environ Saf ; 223: 112557, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34343899

RESUMO

The impact of transgenic crops on non-target organisms is a key aspect of environmental safety assessment to transgenic crops. In the present study, we fed two snail species, Bradybaena (Acusta) ravida (B. ravida) and Bradybaena similaris (Ferussac)(B. similaris), with the leaves of transgenic Bt cotton Zhong 30 (Z30) and control cotton, its parent line zhong 16 (Z16), to assess the environmental safety of Bt cotton to common non-target organisms in the field. Survival, body weight, shell diameter, helix number, reproduction rate, superoxide dismutase (SOD) activity and Bt protein concentration in snails were monitored in 15 days and 180 days experiments. We also monitored the population dynamics of B. ravida and B. similaris in Z30 and Z16 cotton fields for two successive years. Compared to the snails fed on the control cotton Z16, there was no significant difference in survival, growth, reproduction, and SOD activity on Bt cotton Z30. Bt protein concentrations were significantly between different treatments, and Bt protein residues were only detected in the feces of the Z30 treatment. According to the field data, the number of B. ravida and B. similaris fluctuated considerably across seasons over the entire cotton-growing season; however, there were no significant differences between the Bt and control cotton fields at similar time. As the results showed, in our experiments, Bt cotton Z30 had no adverse effects on the two snail species, both in the laboratory and in the fields.


Assuntos
Produtos Agrícolas , Caramujos , Animais , Animais Geneticamente Modificados , Proteínas de Bactérias/genética , Endotoxinas/genética , Endotoxinas/toxicidade , Gossypium/genética , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas , Reprodução , Caramujos/genética
5.
Neotrop Entomol ; 50(5): 804-811, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34398398

RESUMO

Bacillus thuringiensis (Bt)-based bioinsecticides and transgenic plants expressing proteins with insecticidal activity (Cry and Vip) have been successfully used in several integrated pest management programs worldwide. Lepidoptera comprise some of the most economically important insect pests of the major agricultural crops. In this study, the toxicity of 150 Bt strains was evaluated against Helicoverpa armigera (Hübner) larvae. Eight strains (426, 520B, 1636, 1641, 1644, 1648, 1657 and 1658) showed high insecticide activity against H. armigera and were therefore tested against Anticarsia gemmatalis (Hübner), Spodoptera cosmioides (Walker), Chrysodeixis includens (Walker), and Diatraea saccharalis (Fabricius) larvae. Our results showed that most of the Bt strains were also toxic to these lepidopteran species. The biochemical and molecular analyses of these strains revealed that they had a similar protein profile; however, their cry and vip gene contents were variable. In addition, the median lethal concentration (LC50) of the selected strains indicated that the strains 1636, 1641, and 1658 were the most effective against H. armigera, showing LC50 values of 185.02, 159.44, and 192.98 ng/cm2, respectively. Our results suggest that the selected Bt strains have great potential to control the lepidopteran pests H. armigera, A. gemmatalis, D. saccharalis, S. cosmioides, and C. includes.


Assuntos
Bacillus thuringiensis , Agentes de Controle Biológico , Mariposas , Controle Biológico de Vetores , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias , Endotoxinas/toxicidade , Proteínas Hemolisinas , Larva/microbiologia , Mariposas/microbiologia
6.
Chin Med J (Engl) ; 134(15): 1855-1865, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34133355

RESUMO

BACKGROUND: Endotoxin tolerance (ET) is a protective phenomenon in which pre-treatment with a tolerance dose of lipopolysaccharide (LPS) leads to dramatically elevated survival. Accumulating evidence has shown that peripheral T cells contribute to the induction of ET. However, what happens to T cell development in the thymus under ET conditions remains unclear. The purpose of this study was to analyze the alterations in thymocyte populations (double-positive [DP] and single-positive [SP] cells) under ET conditions. METHODS: Mice were intraperitoneally injected with LPS at a concentration of 5 mg/kg to establish an LPS tolerance model and were divided into two groups: a group examined 72 h after LPS injection (72-h group) and a group examined 8 days after LPS injection (8-day group). Injection of phosphate-buffered saline was used as a control (control group). Changes in thymus weight, cell counts, and morphology were detected in the three groups. Moreover, surface molecules such as CD4, CD8, CD44, CD69, and CD62L were analyzed using flow cytometry. Furthermore, proliferation, apoptosis, cytokine production, and extracellular signal-regulated kinase (ERK) pathway signaling were analyzed in thymocyte populations. The polymorphism and length of the T-cell receptor (TCR) ß chain complementarity-determining region 3 (CDR3) were analyzed using capillary electrophoresis DNA laser scanning analysis (ABI 3730). RESULTS: Thymus weight and cell counts were decreased in the early stage but recovered by the late stage in a murine model of LPS-induced ET. Moreover, the proportions of DP cells (control: 72.130 ±â€Š4.074, 72-h: 10.600 ±â€Š3.517, 8-day: 84.770 ±â€Š2.228), CD4+ SP cells (control: 15.770 ±â€Š4.419, 72-h: 44.670 ±â€Š3.089, 8-day: 6.367 ±â€Š0.513), and CD8+ SP cells (control: 7.000 ±â€Š1.916, 72-h: 34.030 ±â€Š3.850, 8-day: 5.133 ±â€Š0.647) were obviously different at different stages of ET. The polymorphism and length of TCR ß chain CDR3 also changed obviously, indicating the occurrence of TCR rearrangement and thymocyte diversification. Further analysis showed that the expression of surface molecules, including CD44, CD69, and CD62L, on thymocyte populations (DP and SP cells) were changed to different degrees. Finally, the proliferation, apoptosis, cytokine production, and ERK pathway signaling of thymocyte populations were changed significantly. CONCLUSION: These data reveal that alterations in thymocyte populations might contribute to the establishment of ET.


Assuntos
Endotoxinas , Timócitos , Animais , Linfócitos T CD4-Positivos , Diferenciação Celular , Endotoxinas/toxicidade , Citometria de Fluxo , Camundongos , Transdução de Sinais , Timo
7.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072918

RESUMO

We previously showed that Lactiplantibacillus plantarum K8 and its cell wall components have immunoregulatory effects. In this study, we demonstrate that pre-treatment of L. plantarum K8 lysates reduced LPS-induced TNF-α production in THP-1 cells by down-regulating the early signals of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB). The down-regulation of signals may be caused by the induction of negative regulators involved in toll-like receptor (TLR)-mediated signaling. However, co-treatment with high concentrations of L. plantarum K8 lysates and lipopolysaccharide (LPS) activated the late signaling of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and NF-κB pathways and resulted in the induction of absent in melanoma 2 (AIM2) inflammasome-mediated interleukin (IL)-1ß secretion. Intraperitoneal injection of L. plantarum K8 lysates in LPS-induced endotoxin shock mice alleviated mortality and reduced serum tumor-necrosis factor (TNF)-α, IL-1ß, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. In addition, the mRNA levels of TNF-α, IL-1ß, and IL-6 decreased in livers from mice injected with L. plantarum K8 followed by LPS. Hematoxylin and eosin (H&E) staining of the liver showed that the cell size was enlarged by LPS injection and slightly reduced by L. plantarum K8 lysate pre-injection followed by LPS injection. Macrophage infiltration of the liver also decreased in response to the combination injection compared with mice injected with only LPS. Taken together, our results show that although L. plantarum K8 lysates differentially regulated the production of LPS-induced inflammatory cytokines in THP-1 cells, the lysates inhibited overall inflammation in mice. Thus, this study suggests that L. plantarum K8 lysates could be developed as a substance that modulates immune homeostasis by regulating inflammation.


Assuntos
Inflamação/genética , Lactobacillaceae/química , Fígado/efeitos dos fármacos , Choque Séptico/genética , Animais , Proteínas de Ligação a DNA/genética , Endotoxinas/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Inflamação/induzido quimicamente , Inflamação/patologia , Interleucina-1beta/genética , Interleucina-6/genética , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Lipopolissacarídeos/farmacologia , Lipopolissacarídeos/toxicidade , Fígado/metabolismo , Fígado/patologia , Camundongos , NF-kappa B/genética , Choque Séptico/induzido quimicamente , Choque Séptico/patologia , Fator de Necrose Tumoral alfa/genética
8.
Int J Mol Sci ; 22(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34074039

RESUMO

The conditioned medium of induced pluripotent stem cells (iPSC-CM) can attenuate neutrophil recruitment and endothelial leakage of lipopolysaccharide (LPS)-induced acute lung injury (ALI). Therefore, we investigated the mechanisms by which iPSC-CM regulate the interaction between neutrophils and the endothelium in ALI. Murine iPSCs (miPSCs) were delivered intravenously to male C57BL/6 mice (8-12 weeks old) 4 h after intratracheal LPS injection. A miPSC-derived conditioned medium (miPSC-CM) was delivered intravenously to mice after intratracheal LPS injection. DMSO-induced HL-60 cells (D-HL-60, neutrophil-like cells) and human umbilical vein endothelial cells (HUVECs) were used as in vitro models to assess the interaction of neutrophils and endothelial cells. miPSC-CM diminished the histopathological changes in the lungs and the neutrophil count in bronchoalveolar lavage fluids of ALI mice. miPSC-CM attenuated the expression of adhesion molecules in the lungs of ALI mice. Human iPSC conditioned medium (hiPSC-CM) reduced the expression of adhesion molecules in a HUVEC and D-HL-60 co-culture after LPS stimulation, which decreased the transendothelial migration (TEM) of D-HL-60. A human angiogenesis factors protein array revealed that leukemia inhibitory factor (LIF) was not detected in the absence of D-HL-60 and hiPSC-CM groups. hiPSC-CM significantly promoted the production of endogenous LIF in in vitro models. Administration of an anti-LIF antibody not only reversed the effect of iPSC-CM in ALI mice, but also blocked the effect of iPSC-CM on neutrophils TEM in in vitro models. However, a controlled IgG had no such effect. Our study demonstrated that iPSC-CM promoted endogenous LIF to inhibit neutrophils TEM and attenuate the severity of sepsis-induced ALI.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Meios de Cultivo Condicionados/farmacologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Fator Inibidor de Leucemia/metabolismo , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/patologia , Animais , Movimento Celular/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Endotoxinas/toxicidade , Células Endoteliais da Veia Umbilical Humana , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo
9.
Chemosphere ; 279: 130862, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34134434

RESUMO

Lead (Pb) entering the body through different channels can damage the function of intestinal mucosal barrier and cause the body stressful inflammatory response to enhance. This study conducted a cross-sectional study to investigate the effects of Pb exposure on intestinal permeability in children by measuring the level of bacterial endotoxin and index of inflammatory cell types in peripheral blood. From November to December 2018, we recruited 187 participants aged 3-6 years by stratified randomization, from an electronic-waste-exposed group (n = 82) and a referent group (n = 105). General demographic information, past history of the digestive system in child, and family situation were informed by children's guardians with questionnaires. Children in the exposed group showed lower weight, height, and body mass index while more diarrhea in a month. Blood Pb and plasma endotoxin were elevated in exposed children than referent children and the positive relationship between them was shown in all children [B (95% CI): 0.072 (0.008, 0.137), P = 0.033]. Peripheral monocyte counts and leukotriene B4 (LTB4) levels were significantly increased in the exposed group. Endotoxin levels were positively correlated with neutrophils, monocytes, and LTB4 [B (95% CI): 0.054 (0.015, 0.093), 0.018 (0.005, 0.031), and 0.049 (0.011, 0.087), respectively, P < 0.05]. To sum up, the exposed children showed lower physical growth levels, poorer gut health, and increased intestinal permeability, which was related to high blood Pb and peripheral inflammatory indices. These results suggest the possible adverse impact of environmental Pb exposure on the intestinal health of children.


Assuntos
Resíduo Eletrônico , Criança , Estudos Transversais , Resíduo Eletrônico/análise , Endotoxinas/toxicidade , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Humanos , Chumbo/toxicidade , Permeabilidade , Reciclagem
10.
Environ Pollut ; 285: 117479, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34090073

RESUMO

Pulmonary injury and inflammation have been detected in cases of subchronic inhalation exposure to reclaimed water, but the mechanism remains unclear. Endotoxin has been verified as the key risk factor in acute inhalation exposure through the TLR4 (Toll-like receptor 4) signalling pathway. In long-term exposure, endotoxin may also be a risk factor in reclaimed water, but the contribution of other health risk factors should not be underestimated. Wild-type C57BL/6J and TLR4-signalling-pathway-defective mice were used in this study to assess the risk of subchronic inhalation exposure to reclaimed water. Two types of reclaimed water, i.e., secondary effluent and MBR (membrane bioreactor) effluent, were found to induce pulmonary injury and inflammation in the wild-type mice and Tlr4-/- mutants. However, when both mice were exposed to the same concentrations of pure endotoxin in reclaimed water, only the wild-type mice that were treated with high-dose endotoxin showed pulmonary injury. In summary, non-TLR4 signalling pathways are related to lung inflammation caused by long-term exposure to reclaimed water. It is highly possible that pollutants in addition to endotoxin in the reclaimed water can induce chronic inflammation in the lung.


Assuntos
Exposição por Inalação , Pneumonia , Animais , Endotoxinas/toxicidade , Exposição por Inalação/efeitos adversos , Camundongos , Camundongos Endogâmicos C57BL , Água
11.
Pestic Biochem Physiol ; 175: 104837, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33993962

RESUMO

Bt protoxins are required to convert to a smaller activated form by insect midgut proteases to exert toxicity against insect pests. Serine protease inhibitors (serpins) play a valuable part in gut protease of insect that hamper digestive proteases activity of insects. Whether the insect serpins induced by Bt protoxin affect the insecticidal activity were rare studied. Here, we identified a serpin-e gene from Helicoverpa armigera, which had potential RCL (Reactive Center Loop) region near the C-terminus like other serpin proteins. It widely expressed in different development stages and in various tissues, but highest expressed in fourth-instar larvae and in larval hemolymph. This Haserpin-e could be induced by Cry1Ac protoxin in vivo and inhibit the midgut proteases to activate Cry1Ac in vitro. Importantly, the functional study indicated it could inhibit the process from Cry1Ac protoxin to activated toxin, and led to the reduction of Cry1Ac insecticide activity to cotton bollworm. Based on our results, we proposed that Haserpin-e involved in the toxicity of Cry1Ac to cotton bollworm by blocking the serine protease to activate the protoxin.


Assuntos
Bacillus thuringiensis , Mariposas , Serpinas , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Endotoxinas/toxicidade , Proteínas Hemolisinas/toxicidade , Resistência a Inseticidas , Larva , Serpinas/genética
12.
Toxins (Basel) ; 13(3)2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33809242

RESUMO

Lipopolysaccharide (LPS) is an endotoxin, which may cause immune response and inflammation of bovine mammary glands. Mastitis impairs animal health and results in economic loss. Curcumin (CUR) is a naturally occurring diketone compound, which has attracted widespread attention as a potential anti-inflammatory antioxidant. The purpose of this study is to investigate whether CUR can reduce the damage of bovine mammary epithelial cells (MAC-T) induced by LPS and its underlying molecular mechanism. The MAC-T cell line was treated with different concentrations of LPS and CUR for 24 h. The results showed that CUR rescued the decrease of MAC-T cell viability and cell damage induced by LPS. At the same time, 10 µM CUR and 100 µg/mL LPS were used to treat the cells in the follow-up study. The results showed CUR treatment reduced the accumulation of reactive oxygen species (ROS), the expression of inflammatory cytokines (tumor necrosis factor-a (TNF-α), interleukin-8 (IL-8), IL-6 and IL-1ß) and the rate of apoptosis induced by LPS. These effects were associated with the activation of the nuclear factor E2-related factor 2 (NFE2L2)-antioxidant response element (ARE) pathway coupled with inactivation of the nuclear factor-κB (NF-κB) inflammatory and caspase/Bcl2 apoptotic pathways.


Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Curcumina/farmacologia , Endotoxinas/toxicidade , Células Epiteliais/efeitos dos fármacos , Mediadores da Inflamação/metabolismo , Glândulas Mamárias Animais/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Bovinos , Linhagem Celular , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
13.
J Physiol ; 599(11): 2969-2986, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33823064

RESUMO

KEY POINTS: The costs associated with immune and thermal responses may exceed the benefits to the host during severe inflammation. In this case, regulated hypothermia instead of fever can occur in rodents as a beneficial strategy to conserve energy for vital functions with consequent tissue protection and hypoxia prevention. We tested the hypothesis that this phenomenon is not exclusive to mammals, but extends to the other endothermic group, birds. A decrease in metabolic rate without any failure in mitochondrial respiration, nor oxygen delivery, is the main evidence supporting the regulated nature of endotoxin-induced hypothermia in chicks. Thermolytic mechanisms such as tachypnea and cutaneous vasodilatation can also be recruited to facilitate body temperature decrease under lipopolysaccharide treatment, especially in the cold. Our findings bring a new perspective for evolutionary medicine studies on energy trade-off in host defence because regulated hypothermia may be a phenomenon spread among vertebrates facing a severe immune challenge. ABSTRACT: A switch from fever to regulated hypothermia can occur in mammals under circumstances of reduced physiological fitness (e.g. sepsis) to direct energy to defend vital systems. Birds in which the cost to resist a pathogen is additive to the highest metabolic rate and body temperature (Tb ) among vertebrates may also benefit from regulated hypothermia during systemic inflammation. Here, we show that the decrease in Tb observed during an immune challenge in birds is a regulated hypothermia, and not a result of metabolic failure. We investigated O2 consumption (thermogenesis index), ventilation (respiratory heat loss), skin temperature (sensible heat loss) and muscle mitochondrial respiration (thermogenic tissue) during Tb fall in chicken chicks challenged with endotoxin [lipopolysaccharide (LPS)]. Chicks injected with LPS were also tested regarding the capacity to raise O2 consumption to meet an increased demand driven by 2,4-dinitrophenol. LPS decreased Tb and the metabolic rate of chicks without affecting muscle uncoupled, coupled and non-coupled mitochondrial respiration. LPS-challenged chicks were indeed capable of increasing metabolic rate in response to 2,4-dinitrophenol, indicating no O2 delivery limitation. Additionally, chicks did not attempt to prevent Tb from falling during hypothermia but, instead, activated cutaneous and respiratory thermolytic mechanisms, providing an additional cooling force. These data provide the first evidence of the regulated nature of the hypothermic response to endotoxin in birds. Therefore, it changes the current understanding of bird's thermoregulation during severe inflammation, indicating that regulated hypothermia is either a convergent trait for endotherms or a conserved response among vertebrates, which adds a new perspective for evolutionary medicine research.


Assuntos
Hipotermia , Animais , Temperatura Corporal , Regulação da Temperatura Corporal , Galinhas , Endotoxinas/toxicidade
14.
Int J Pediatr Otorhinolaryngol ; 144: 110669, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33761375

RESUMO

OBJECTIVE: To investigate the expression and correlation of vascular endothelial growth factor (VEGF) and its receptor with hypoxia-inducible factor-1 α (HIF-1 α) in otitis media with effusion (OME). METHODS: A rat model of OME was induced by injection of lipopolysaccharide (LPS) into the middle ear. Hematoxylin and eosin (HE) staining was used to observe the pathomorphological changes of the tympanic cavity in the middle ear of rats. Immunohistochemistry (IHC), western blotting and RT-qPCR were used to determine the mRNA and protein expression of VEGF, VEGFR-1, VEGFR-2 and HIF-1α in mucosa of tympanic cavity mucosa, respectively. RESULTS: In the OME group, the epithelial space of the middle ear mucosa was significantly thickened and infiltration of a large number of inflammatory cells was found on postoperative day (POD), and the otitis media basically subsided 2 weeks after operation. VEGF mRNA expression was significantly increased on POD 1, and its protein expression peaked on POD 3. HIF-1α mRNA expression was significantly increased and peaked on POD 1, while its protein expression began to increase on POD 3 and was significantly expressed in the middle ear mucosal epithelium. HIF-1α mRNA showed a positive correlation with VEGF mRNA and VEGFR-1 mRNA expression. CONCLUSION: VEGF mainly plays a role in the acute phase of OME, and it is abundantly expressed mediated by HIF-1α. And then it play a role in vasodilatation and increase of vascular permeability, thus promoting the generation of middle ear effusion.


Assuntos
Otite Média com Derrame , Animais , Endotoxinas/toxicidade , Ratos , Fator A de Crescimento do Endotélio Vascular , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Fatores de Crescimento do Endotélio Vascular
15.
Front Immunol ; 12: 641999, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33777038

RESUMO

αB-Crystallin, a member of the small heat shock protein (sHSP) family, plays an immunomodulatory and neuroprotective role by inhibiting microglial activation in several diseases. However, its effect on endotoxin-induced uveitis (EIU) is unclear. Autophagy may be associated with microglial activation, and αB-crystallin is involved in the regulation of autophagy in some cells. The role of αB-crystallin in microglial autophagy is unknown. This study aimed to explore the role of αB-crystallin on retinal microglial autophagy, microglial activation, and neuroinflammation in both cultured BV2 cells and the EIU mouse model. Our results show that αB-crystallin reduced the release of typical proinflammatory cytokines at both the mRNA and protein level, inhibited microglial activation in morphology, and suppressed the expression of autophagy-related molecules and the number of autophagolysosomes in vitro. In the EIU mouse model, αB-crystallin treatment alleviated the release of ocular inflammatory cytokines and the representative signs of inflammation, reduced the apoptosis of ganglion cells, and rescued retinal inflammatory structural and functional damage, as evaluated by optical coherence tomographic and electroretinography. Taken together, these results indicate that αB-crystallin inhibits the activation of microglia and supresses microglial autophagy, ultimately reducing endotoxin-induced neuroinflammation. In conclusion, αB-crystallin provides a novel and promising option for affecting microglial autophagy and alleviating symptoms of ocular inflammatory diseases.


Assuntos
Microglia/metabolismo , Uveíte/metabolismo , Uveíte/patologia , Cadeia B de alfa-Cristalina/metabolismo , Animais , Autofagia/fisiologia , Endotoxinas/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Retina/metabolismo , Retina/patologia , Uveíte/induzido quimicamente
16.
Nanotoxicology ; 15(4): 558-576, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33784953

RESUMO

The interaction between engineered nanoparticles and the bacterial lipopolysaccharide, or endotoxin, is an event that warrants attention. Endotoxin is one of the most potent stimulators of inflammation and immune reactions in human beings, and is a very common contaminant in research labs. In nanotoxicology and nanomedicine, the presence of endotoxin on the nanoparticle surface affects their biological properties leading to misinterpretation of results. This review discusses the importance of detecting the endotoxin contamination on nanoparticles, focusing on the current method of endotoxin detection and their suitability for nanoparticulate materials. Conversely, the capacity of nanoparticles to bind endotoxin can be enhanced by functionalization with endotoxin-capturing molecules, opening the way to the development of novel endotoxin detection assays.


Assuntos
Nanopartículas , Bioensaio , Endotoxinas/toxicidade , Humanos , Inflamação , Lipopolissacarídeos/toxicidade , Nanopartículas/toxicidade
17.
J Vis Exp ; (168)2021 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-33682855

RESUMO

Sepsis and septic shock remain the leading cause of death in intensive care units. Despite significant improvements in sepsis management, mortality still ranges between 20 and 30%. Novel treatment approaches in order to reduce sepsis-related multiorgan failure and death are urgently needed. Robust animal models allow for one or multiple treatment approaches as well as for testing their effect on physiological and molecular parameters. In this article, a simple animal model is presented. First, general anesthesia is induced in animals either with the use of volatile or by intraperitoneal anesthesia. After placement of an intravenous catheter (tail vein), tracheostomy, and insertion of an intraarterial catheter (tail artery), mechanical ventilation is started. Baseline values of mean arterial blood pressure, arterial blood oxygen saturation, and heart rate are recorded. The injection of lipopolysaccharides (1 milligram/kilogram body weight) dissolved in phosphate-buffered saline induces a strong and reproducible inflammatory response via the toll-like receptor 4. Fluid corrections as well as the application of norepinephrine are performed based on well-established protocols. The animal model presented in this article is easy to learn and strongly oriented towards clinical sepsis treatment in an intensive care unit with sedation, mechanical ventilation, continuous blood pressure monitoring, and repetitive blood sampling. Also, the model is reliable, allowing for reproducible data with a limited number of animals in accordance with the 3R (reduce, replace, refine) principles of animal research. While animal experiments in sepsis research cannot easily replaced, repetitive measurements allow for a reduction of animals and keeping septic animals anesthetized diminishes suffering.


Assuntos
Endotoxinas/toxicidade , Unidades de Terapia Intensiva , Anestesia , Animais , Artérias/fisiologia , Modelos Animais de Doenças , Masculino , Monitorização Fisiológica , Ratos Wistar , Reprodutibilidade dos Testes , Sepse/patologia , Traqueostomia , Veias/fisiologia
18.
FASEB J ; 35(4): e21334, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33715200

RESUMO

Sepsis and sepsis-associated lung inflammation significantly contribute to the morbidity and mortality of critical illness. Here, we examined the hypothesis that neuronal guidance proteins could orchestrate inflammatory events during endotoxin-induced lung injury. Through a targeted array, we identified netrin-1 as the top upregulated neuronal guidance protein in macrophages treated with lipopolysaccharide (LPS). Furthermore, we found that netrin-1 is highly enriched in infiltrating myeloid cells, particularly in macrophages during LPS-induced lung injury. Transcriptional studies implicate hypoxia-inducible factor HIF-1α in the transcriptional induction of netrin-1 during LPS treatment. Subsequently, the deletion of netrin-1 in the myeloid compartment (Ntn1loxp/loxp LysM Cre) resulted in exaggerated mortality and lung inflammation. Surprisingly, further studies revealed enhanced natural killer cells (NK cells) infiltration in Ntn1loxp/loxp LysM Cre mice, and neutralization of NK cell chemoattractant chemokine (C-C motif) ligand 2 (CCL2) reversed the exaggerated lung inflammation. Together, these studies provide functional insight into myeloid cell-derived netrin-1 in controlling lung inflammation through the modulation of CCL2-dependent infiltration of NK cells.


Assuntos
Endotoxinas/toxicidade , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Células Matadoras Naturais/fisiologia , Lesão Pulmonar/induzido quimicamente , Netrina-1/metabolismo , Animais , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Citocinas/genética , Citocinas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos , Células Mieloides/efeitos dos fármacos , Netrina-1/genética , Neutrófilos/fisiologia , Regulação para Cima
19.
Biochim Biophys Acta Proteins Proteom ; 1869(6): 140634, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33636413

RESUMO

One proposed toxic mechanism of Bacillus thuringiensis Cry δ-endotoxins involves pore formation in target membranes by the α4-α5 transmembrane hairpin constituting their pore-forming domain. Here, nine selected charged and uncharged polar residues in the pore-lining α4 of the Cry4Aa mosquito-active toxin were substituted with Ala. All mutant toxins, i.e., D169A, R171A, Q173A, H178A, Y179A, H180A, Q182A, N183A and E187A, were over-expressed in Escherichia coli as 130-kDa protoxin inclusions at levels comparable to the wild-type toxin. Bioassays against Aedes aegypti larvae revealed that only H178A and H180A mutants displayed a drastic reduction in biotoxicity, albeit almost complete insolubility observed for H178A, but not for H180A inclusions. Further mutagenic analysis showed that replacements of His180 with charged (Arg, Lys, Asp, Glu), small uncharged polar (Ser, Cys) or small non-polar (Gly, Val) residues severely impaired the biotoxicity, unlike substitutions with relatively large uncharged (Asn, Gln, Leu) or aromatic (Phe, Tyr, Trp) residues. Similar to the trypsin-activated wild-type toxin, both bio-active and -inactive H180 mutants were still capable of releasing entrapped calcein from lipid vesicles and producing cation-selective channels with ~130-pS maximum conductance. Analysis of the Cry4Aa structure revealed the existence of a hydrophobic cavity near the critical His180 side-chain. Analysis of simulated structures revealed that His180-to-smaller residue conversions create a gap disrupting such cavity's hydrophobicity and hence structural arrangements of the α4-α5 hairpin. Altogether, our data disclose a critical involvement in Cry4Aa-biotoxicity of His180 exclusively present in the lumen-facing α4 for providing proper environment for the α4-α5 hairpin prior to membrane-inserted pore formation.


Assuntos
Aedes/crescimento & desenvolvimento , Toxinas de Bacillus thuringiensis/química , Toxinas de Bacillus thuringiensis/toxicidade , Bacillus thuringiensis/metabolismo , Endotoxinas/química , Endotoxinas/toxicidade , Proteínas Hemolisinas/química , Proteínas Hemolisinas/toxicidade , Histidina/genética , Aedes/efeitos dos fármacos , Substituição de Aminoácidos , Animais , Bacillus thuringiensis/química , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis/genética , Endotoxinas/genética , Fluoresceínas/metabolismo , Proteínas Hemolisinas/genética , Interações Hidrofóbicas e Hidrofílicas , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Modelos Moleculares , Simulação de Dinâmica Molecular , Domínios Proteicos , Estrutura Secundária de Proteína
20.
Exp Eye Res ; 206: 108520, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33617852

RESUMO

Short chain fatty acids (SCFAs) are produced by gut microbiota as fermentation products of digestion-resistant oligosaccharides and fibers. Their primary roles are functioning as major energy sources for colon cells and assisting in gut homeostasis by immunomodulation. Recent evidence suggests that they affect various organs both at cellular and molecular levels, and regulate functions in distance sites including gene expression, cell proliferation, cell differentiation, apoptosis and inflammation. In this study, we examined whether SCFAs are present in the mouse eye and whether SCFAs affect inflammatory responses of the eye and retinal astrocytes (RACs). We observed that intra-peritoneal injected SCFAs were detected in the eye and reduced intraocular inflammation induced by lipopolysaccharide (LPS). Moreover, SCFAs displayed two disparate effects on LPS-stimulated RACs - namely, cytokine and chemokine production was reduced, but the ability to activate T cells was enhanced. Our results support the existence of gut-eye cross talk and suggest that SCFAs can cross the blood-eye-barrier via the systemic circulation. If applied at high concentrations, SCFAs may reduce inflammation and impact cellular functions in the intraocular milieu.


Assuntos
Astrócitos/patologia , Ácidos Graxos Voláteis/farmacologia , Inflamação/terapia , Células Ganglionares da Retina/patologia , Uveíte/terapia , Animais , Proliferação de Células , Modelos Animais de Doenças , Endotoxinas/toxicidade , Feminino , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Camundongos Endogâmicos C57BL , Uveíte/metabolismo , Uveíte/patologia
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