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1.
BMC Public Health ; 24(1): 624, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38413881

RESUMO

BACKGROUND: The Lafiyan Yara Project aimed to increase demand for HIV counselling, testing, treatment, and prevention services among pregnant women and children in Taraba State, Nigeria. Implemented from 2019 to 2021, the project utilized existing community structures, including traditional birth attendants, village health workers, and patent and proprietary medicine vendors, for mobilization. This study assessed the project's activities, contributors, relevance, effectiveness, and efficiency. METHODS: The process evaluation was conducted using focus group discussions and key informant interviews with beneficiaries, community leaders, project staff, health facility personnel, and government officials. Data analysis employed framework analysis. RESULTS: The Lafiyan Yara project was reported to have achieved notable successes, including increased HIV testing rates among children and pregnant women, improved linkage to care services, reduced mother-to-child transmission of HIV, increased HIV/AIDS awareness and knowledge, and enhanced community engagement and support. Challenges identified included insufficient funding for community mobilizers, training needs for health workers, and inadequate availability of test kits at health facilities. Confidentiality and stigma issues arose during community mobilizations. A key lesson learned was the importance of a comprehensive HIV care approach, emphasizing testing and ensuring support for individuals testing positive. CONCLUSIONS: The project's approach of leveraging community structures to create demand for HIV services among women and children proved effective, provided proper linkage to care for those testing positive. Addressing stigma and involving husbands/fathers in the community approach are crucial for improving outcomes. TRIAL REGISTRATION: IPHOAU/12/1384.


Assuntos
Infecções por HIV , Humanos , Feminino , Gravidez , Nigéria , Infecções por HIV/diagnóstico , Infecções por HIV/prevenção & controle , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Gestantes , Teste de HIV
2.
Glob Public Health ; 18(1): 2284880, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38015746

RESUMO

Nigeria carries a high burden of HIV infections, with Taraba State having a prevalence of 2.49%. This quasi-experimental study evaluated the impact of the Lafiyan Yara project, which utilised various community-based mobilisation models, on the enhancement of HTS uptake among women during pregnancy, and children. The intervention involved the implementation of mobilisation by Traditional Birth Attendants (TBA), Village Health Workers (VHW), Patent and Proprietary Medicine Vendors (PPMVs), and a combination of the three in four study local government areas (LGA) in Taraba State. Baseline and end-line surveys were conducted focused on women aged 15-49 years who delivered a child in the past 1 year, and children in their households, in the study and a control LGA. A difference-in-difference (DID) approach was applied by using a probit regression model with interaction terms for treatment status (intervention vs. control) and survey timing to compute the DID estimates of uptake of HTS. The TBA model showed the highest impact in the referral of women to HTS, while the combined model demonstrated the greatest impact in referrals for children. Scaling up and strengthening these community mobilisation efforts can improve access to HIV testing and contribute to HIV/AIDS prevention and control in the region.


Assuntos
Infecções por HIV , Tocologia , Gravidez , Humanos , Criança , Feminino , Nigéria/epidemiologia , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Serviços de Saúde , Teste de HIV
3.
Drug Deliv Transl Res ; 13(7): 1882-1895, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36182992

RESUMO

Neutrophils are the most abundant white blood cells in circulation and constitute up to 60% of circulating leukocytes. Neutrophils play a significant role in host defense against pathogens through various mechanisms, including phagocytosis, production of antimicrobial proteins, and formation of neutrophil extracellular traps (NETs). Recently, the role of neutrophils and NETs in cancer has generated significant interest, as accumulating evidence suggests that neutrophils and NETs contribute to cancer progression and are associated with adverse patient outcomes. In this review, we will first highlight the roles of neutrophils and NETs in cancer progression and metastasis and discuss new drug delivery approaches to target and modulate neutrophils and NETs for cancer therapeutics.


Assuntos
Armadilhas Extracelulares , Neoplasias , Humanos , Neutrófilos/metabolismo , Neutrófilos/patologia , Armadilhas Extracelulares/metabolismo , Neoplasias/patologia
4.
Molecules ; 27(12)2022 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35744990

RESUMO

Potato protein-derived decapeptide DIKTNKPVIF exerted anti-inflammatory activity in animal models when delivered via intragastric gavage and intraperitoneal injection. However, DIKTNKPVIF is susceptible to hydrolysis in the digestive tract, which will decrease its bioaccessibility and possibly bioactivity. In this study, the anti-inflammatory activity of fragments generated from in silico gastrointestinal enzymatic hydrolysis of DIKTNKPVIF was investigated using the human monocytic (THP-1) cell line. The simulated digestion by pepsin and trypsin released four fragments, DIKTNKPVI, TNKPVIF, DIK and TNKPVI. The peptides lacked the cleavage sites of chymotrypsin. All five peptides were predicted to be non-toxic, which was validated using cytotoxicity assay at 0.25-1 mM peptide concentration. However, the peptides were predicted to possess poor pharmacokinetic profiles, including low passive gastrointestinal absorption and blood-brain barrier permeability. TNKPVIF, DIK and TNKPVI significantly reduced the amount of pro-inflammatory interleukin (IL)-6, IL-8 and tumor necrosis factor in lipopolysaccharide-activated THP-1 cells. Notably, the anti-inflammatory activity of fragment TNKPVI was comparable to that of the parent decapeptide while peptide fragment DIKTNKPVI had no apparent effect on the pro-inflammatory cytokines. This highlights the important role of the C-terminal phenylalanine residue of the parent peptide in the bioactivity. Furthermore, given its activity and the absence of cleavage sites of major digestive proteases, TNKPVI could be the biostable and bioaccessible pharmacophore of potato patatin-derived anti-inflammatory decapeptide DIKTNKPVIF.


Assuntos
Solanum tuberosum , Animais , Anti-Inflamatórios/farmacologia , Citocinas , Peptídeos/química , Solanum tuberosum/química , Fator de Necrose Tumoral alfa/metabolismo
5.
Front Immunol ; 13: 902206, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35757734

RESUMO

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic. Majority of COVID-19 patients have mild disease but about 20% of COVID-19 patients progress to severe disease. These patients end up in the intensive care unit (ICU) with clinical manifestations of acute respiratory distress syndrome (ARDS) and sepsis. The formation of neutrophil extracellular traps (NETs) has also been associated with severe COVID-19. Understanding of the immunopathology of COVID-19 is critical for the development of effective therapeutics. In this article, we discuss evidence indicating that severe COVID-19 has clinical presentations consistent with the definitions of viral sepsis. We highlight the role of neutrophils and NETs formation in the pathogenesis of severe COVID-19. Finally, we highlight the potential of therapies inhibiting NETs formation for the treatment of COVID-19.


Assuntos
COVID-19 , Armadilhas Extracelulares , Sepse , Humanos , Pandemias , SARS-CoV-2
6.
J Control Release ; 337: 168-178, 2021 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-34280415

RESUMO

Conventional cancer vaccines based on soluble vaccines and traditional adjuvants have produced suboptimal therapeutic efficacy in clinical trials. Thus, there is an urgent need for vaccine technologies that can generate potent T cell responses with strong anti-tumor efficacy. We have previously reported the development of synthetic high-density protein (sHDL) nanodiscs for efficient lymph node (LN)-targeted co-delivery of antigen peptides and CpG oligonucleotides (a Toll-like receptor-9 agonist). Here, we performed a comparative study in mice and non-human primates (NHPs) to identify an ideal vaccine platform for induction of CD8+ T cell responses. In particular, we compared the efficacy of CpG class B, CpG class C, and polyICLC (a synthetic double-stranded RNA analog, a TLR-3 agonist), each formulated with antigen-carrying sHDL nanodiscs. Here, we report that sHDL-Ag admixed with polyICLC elicited robust Ag-specific CD8+ T cell responses in mice, and when used in combination with α-PD-1 immune checkpoint inhibitor, sHDL-Ag + polyICLC eliminated large established (~100 mm3) MC-38 tumors in mice. Moreover, sHDL-Gag + polyICLC induced robust Simian immunodeficiency virus Gag-specific, polyfunctional CD8+ T cell responses in rhesus macaques and could further amplify the efficacy of recombinant adenovirus-based vaccine. Notably, while both sHDL-Ag-CpG-B and sHDL-Ag-CpG-C generated strong Ag-specific CD8+ T cell responses in mice, their results were mixed in NHPs. Overall, sHDL combined with polyICLC offers a strong platform to induce CD8+ T cells for vaccine applications.


Assuntos
Linfócitos T CD8-Positivos , Vacinas Anticâncer , Adjuvantes Imunológicos , Animais , Macaca mulatta , Camundongos , Vacinas Sintéticas
7.
Seizure ; 84: 1-5, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33248424

RESUMO

BACKGROUND: Epilepsy, a chronic seizure disorder, can cause elevated fatigue and reduced quality of life (QOL) of the sufferers. Hence, improving QOL, seizure severity (SS) and fatigue are important areas of therapeutic interventions for people living with epilepsy (PLWE). Therefore, there is need to ascertain the levels and interrelationships among these constructs in PLWE. OBJECTIVE: This study compared fatigue and QOL of PLWE with those of apparently healthy individuals (AHIs) and also determined the interrelationships between fatigue, QOL and SS in PLWE. METHOD: This cross-sectional survey involved 91 PLWE and 101 AHIs consecutively recruited from purposively selected hospitals and hosting communities. The Short-form Health Survey (SF-36) questionnaire, the Fatigue Severity Scale, the Modified Fatigue Impact Scale and the Seizure Severity Questionnaire were used to evaluate QOL, fatigue severity (FS), fatigue impact (FI) and SS respectively. Data was analyzed using frequency count, proportions, mean and standard deviation, range, Chi-square test, Mann-Whitney U test and Spearman-rank order correlation. Alpha level was set at 0.05. RESULTS: PLWE had significantly lower QOL compared to AHIs (U = 3057.00;p < 0.01). The two groups however experienced similar fatigue severity, but PWE suffered greater fatigue impact (U = 2798.00;p < 0.01). Significant relationships existed among FI, FS, SS and QOL in PLWE (p < 0.01). CONCLUSION: Compared with AHIs, PLWE had poorer QOL, similar FS, and higher FI. QOL of PLWE was negatively associated with SS, FI and FS. Clinical interventions geared towards minimizing seizure, severity and impact of fatigue may improve the QOL of PLWE.


Assuntos
Epilepsia , Qualidade de Vida , Estudos Transversais , Epilepsia/epidemiologia , Fadiga/epidemiologia , Fadiga/etiologia , Humanos , Nigéria , Convulsões/epidemiologia
8.
Ann Glob Health ; 86(1): 118, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32983914

RESUMO

Background: Cervical cancer deaths are disproportionately higher in developing countries depicting one of the most profound health disparities existing today and is ranked as the second most frequent cancer among women in Nigeria. The Human Papillomavirus (HPV) vaccine as a primary prevention strategy is not widely used in Nigeria. This study investigated perceived barriers to HPV vaccination in a Nigerian community, targeting health workers' perceptions. Methods: This descriptive study captured responses from a cross-sectional, convenience sample of adult health workers within Anambra State, Nigeria. An anonymous 42-item survey with multiple validated scales was developed based on the Theory of Planned Behavior model and previous studies. The self-administered survey was distributed by research assistants at study sites within Anambra State which were identified through local constituents by the regional zones Adazi-Ani, Onitsha, and Awka. Data analyses were performed using Microsoft Excel for descriptive statistics and R software for the logistic regression, with a statistical significance level of 5%. Subgroup analysis was performed for the baseline knowledge questionnaire to determine if there were any differences in correct responses based on demographics such as: Institution type, profession, age, sex, religion and parental status. Results: Responses were collected from 137 Nigerian health workers; 44% nurses, 14% physicians, 6% pharmacists and 31% other health workers. The majority of respondents were female (69%), between 18 and 39 years of age (78%), from urban settings (82%), and identified as having Christian religious beliefs (97%). The most significant barriers identified were lack of awareness (39%), vaccine availability (39%), and cost (13%). When asked baseline knowledge questions regarding HPV, females were more likely to answer incorrectly as compared to males. Significant differences were found for statements: (1) HPV is sexually transmitted (p = 0.008) and (2) HPV is an infection that only affects women (p = 0.004). Conclusions: Perceived barriers to HPV vaccination identified by Nigerian health workers include lack of awareness, vaccine availability/accessibility, cost, and concerns about acceptability. Ongoing efforts to subsidize vaccine costs, campaigns to increase awareness of HPV vaccine, and interventions to improve attainability could advance administration rates in Nigeria, and ultimately improve death rates due to cervical cancer in this population.


Assuntos
Alphapapillomavirus , Infecções por Papillomavirus , Vacinas contra Papillomavirus , Neoplasias do Colo do Útero , Adulto , Estudos Transversais , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Nigéria , Infecções por Papillomavirus/epidemiologia , Infecções por Papillomavirus/prevenção & controle , Aceitação pelo Paciente de Cuidados de Saúde , Inquéritos e Questionários , Neoplasias do Colo do Útero/prevenção & controle , Vacinação
9.
Nano Lett ; 20(10): 7783-7792, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-32926633

RESUMO

Cancer stem cells (CSCs) proliferate extensively and drive tumor metastasis and recurrence. CSCs have been identified in over 20 cancer types to date, but it remains unknown how to target and eliminate CSCs in vivo. Aldehyde dehydrogenase (ALDH) is a marker that has been used extensively for isolating CSCs. Here we present a novel approach to target and reduce the frequency of ALDHhigh CSCs by vaccination against ALDH. We have identified ALDH1-A1 and ALDH1-A3 epitopes from CSCs and developed synthetic high-density lipoprotein nanodiscs for vaccination against ALDHhigh CSCs. Nanodiscs increased antigen trafficking to lymph nodes and generated robust ALDH-specific T cell responses. Nanodisc vaccination against ALDHhigh CSCs combined with anti-PD-L1 therapy exerted potent antitumor efficacy and prolonged animal survival in multiple murine models. Overall, this is the first demonstration of a simple nanovaccine strategy against CSCs and may lead to new avenues for cancer immunotherapy against CSCs.


Assuntos
Neoplasias , Vacinas , Aldeído Desidrogenase , Família Aldeído Desidrogenase 1 , Animais , Linhagem Celular Tumoral , Imunoterapia , Camundongos , Neoplasias/terapia , Células-Tronco Neoplásicas
10.
Biomaterials ; 238: 119836, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32045782

RESUMO

Neutrophil elastase (NE) is a serine protease stored in the azurophilic granules of neutrophils and released into the extracellular milieu during inflammatory response or formation of neutrophil extracellular traps (NETs). Neutrophils release NETs to entrap pathogens by externalizing their cellular contents in a DNA framework decorated with anti-microbials and proteases, including NE. Importantly, excess NETs in tissues are implicated in numerous pathologies, including sepsis, rheumatoid arthritis, vasculitis, and cancer. However, it remains unknown how to effectively prevent NET formation. Here, we show that NE plays a major role during NET formation and that inhibition of NE is a promising approach for decreasing NET-mediated tissue injury. NE promoted NET formation by human neutrophils. Whereas sivelestat, a small molecule inhibitor of NE, inhibited the formation of NETs in vitro , administration of free sivelestat did not have any efficacy in a murine model of lipopolysaccharide-induced endotoxic shock. To improve the efficacy of sivelestat in vivo, we have developed a nanoparticle system for delivering sivelestat. We demonstrate that nanoparticle-mediated delivery of sivelestat effectively inhibited NET formation, decreased the clinical signs of lung injury, reduced NE and other proinflammatory cytokines in serum, and rescued animals against endotoxic shock. Collectively, our data demonstrates that NE signaling can initiate NET formation and that nanoparticle-mediated inhibition of NE improves drug efficacy for preventing NET formation.


Assuntos
Armadilhas Extracelulares , Preparações Farmacêuticas , Animais , Elastase de Leucócito , Lipopolissacarídeos , Camundongos , Neutrófilos
11.
Front Immunol ; 10: 680, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31024539

RESUMO

The distinction between innate and adaptive immunity is one of the basic tenets of immunology. The co-operation between these two arms of the immune system is a major determinant of the resistance or susceptibility of the host following pathogen invasion. Hence, this interactive co-operation between cells of the innate and adaptive immunity is of significant interest to immunologists. The sub-population of CD4+ T cells with regulatory phenotype (regulatory T cells; Tregs), which constitute a part of the adaptive immune system, have been widely implicated in the regulation of the immune system and maintenance of immune homeostasis. In the last two decades, there has been an explosion in research describing the role of Tregs and their relevance in several immunopathologies ranging from inflammation to cancer. The majority of these studies focus on the role of Tregs on the cells of the adaptive immune system. Recently, there is significant interest in the role of Tregs on cells of the innate immune system. In this review, we examine the literature on the role of Tregs in immunology. Specifically, we focus on the emerging knowledge of Treg interaction with dendritic cells, macrophages, neutrophils, and γδ T cells. We highlight this interaction as an important link between innate and adaptive immune systems which also indicate the far-reaching role of Tregs in the regulation of immune responses and maintenance of self-tolerance and immune homeostasis.


Assuntos
Imunidade Inata/imunologia , Linfócitos T Reguladores/imunologia , Imunidade Adaptativa/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Células Dendríticas/imunologia , Homeostase/imunologia , Humanos , Tolerância Imunológica/imunologia , Tolerância a Antígenos Próprios/imunologia
12.
J Immunol ; 199(3): 1086-1095, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28659355

RESUMO

Despite decades of clinical and biomedical research, the pathogenesis of sepsis and its spectrum of diseases (severe sepsis and septic shock), which are leading causes of death in intensive care units, are still poorly understood. In this article, we show that signaling via the p110δ isoform of PI3K is critical for survival in experimental sepsis. Mice with an inactive knock-in mutation in the p110δ gene (p110δD910A) succumbed acutely to nonlethal dose LPS challenge. The susceptibility of p110δD910A mice to LPS was associated with increased neutrophil numbers and activities in the tissues, due in part to delayed apoptosis resulting mostly from inherent reduced regulatory T cell (Treg) numbers. Adoptive transfer of wild-type or p110δD910A Tregs abrogated exaggerated neutrophil activity, increased neutrophil apoptosis, and rescued p110δD910A mice from mortality after LPS challenge. We confirmed the clinical relevance of these findings by showing that human Tregs also regulate neutrophil function and survival. Collectively, our results show that PI3K δ is essential for survival during sepsis. In addition, our data highlight the importance of Tregs in regulating the pathogenesis of sepsis and septic shock via their effects on neutrophil survival and function, and provide evidence of regulation of innate immunity by cells of the adaptive immune system.


Assuntos
Neutrófilos/imunologia , Fosfatidilinositol 3-Quinases/metabolismo , Sepse/imunologia , Choque Séptico/mortalidade , Linfócitos T Reguladores/imunologia , Animais , Apoptose , Diferenciação Celular , Proliferação de Células/genética , Proliferação de Células/fisiologia , Classe I de Fosfatidilinositol 3-Quinases , Técnicas de Introdução de Genes , Imunidade Inata , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/imunologia , Ativação Linfocitária , Camundongos , Neutrófilos/patologia , Neutrófilos/fisiologia , Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/genética , Isoformas de Proteínas , Sepse/fisiopatologia , Choque Séptico/imunologia , Choque Séptico/fisiopatologia , Transdução de Sinais
13.
J Innate Immun ; 8(2): 156-70, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26771196

RESUMO

In spite of over half a century of research, sepsis still constitutes a major problem in health care delivery. Although advances in research have significantly increased our knowledge of the pathogenesis of sepsis and resulted in better prognosis and improved survival outcome, sepsis still remains a major challenge in modern medicine with an increase in occurrence predicted and a huge socioeconomic burden. It is generally accepted that sepsis is due to an initial hyperinflammatory response. However, numerous efforts aimed at targeting the proinflammatory cytokine network have been largely unsuccessful and the search for novel potential therapeutic targets continues. Recent studies provide compelling evidence that dysregulated anti-inflammatory responses may also contribute to sepsis mortality. Our previous studies on the role of regulatory T cells and phosphoinositide 3-kinases in sepsis highlight immunological approaches that could be explored for sepsis therapy. In this article, we review the current and emerging concepts in sepsis, highlight novel potential therapeutic targets and immunological approaches for sepsis treatment and propose a biphasic treatment approach for management of the condition.


Assuntos
Cuidados Críticos/métodos , Fosfatidilinositol 3-Quinases/imunologia , Sepse , Linfócitos T Reguladores , Animais , Cuidados Críticos/tendências , Humanos , Sepse/imunologia , Sepse/patologia , Sepse/terapia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/patologia
14.
J Immunol ; 193(2): 655-62, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24943218

RESUMO

Regulatory T cells (Tregs) are essential for maintenance of peripheral tolerance, and defects in Treg function have been linked to several autoimmune diseases. We previously reported that depletion of Tregs resulted in mortality to an otherwise nonlethal dose of LPS or Escherichia coli challenge. In this study, we investigated the mechanism by which Treg depletion leads to enhanced susceptibility to LPS. Using different murine lymphocyte gene knockout models, we show that the enhanced sensitivity to LPS following Treg depletion is mediated by T cells. SCID or RAG1-deficient mice, which lack T and B cells, do not show enhanced susceptibility to LPS. However, reconstitution of SCID mice with wild-type CD4(+) T cells restored Treg depletion-induced sensitivity to LPS. This CD4(+) T cell-mediated hypersensitivity to LPS challenge in the absence of Tregs was also observed upon reconstitution of SCID mice with CD4(+) T cells from CD25 knockout mice (which lack functional Tregs). Additionally, depletion of Tregs leads to increased CD4(+) T cell proliferation and proinflammatory cytokine production in response to LPS challenge. Some CD4(+) T cells express TLR4, and pretreatment of CD4(+) T cells with LPS dramatically enhanced their ability to induce inflammatory cytokine production by macrophages. Collectively, our results indicate that in the absence of functional Tregs, CD4(+) T cells are pathologic and contribute to exaggerated immune activation that is detrimental for survival in LPS-induced acute inflammation. Our data also provide evidence for direct activation of CD4(+) T cells by LPS through TLR4.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Inflamação/imunologia , Lipopolissacarídeos/imunologia , Ativação Linfocitária/imunologia , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/transplante , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Técnicas de Cocultura , Feminino , Citometria de Fluxo , Inflamação/induzido quimicamente , Mediadores da Inflamação/imunologia , Mediadores da Inflamação/metabolismo , Subunidade alfa de Receptor de Interleucina-2/deficiência , Subunidade alfa de Receptor de Interleucina-2/genética , Subunidade alfa de Receptor de Interleucina-2/imunologia , Lipopolissacarídeos/toxicidade , Depleção Linfocítica , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos SCID , Linfócitos T Reguladores/metabolismo , Receptor 4 Toll-Like/deficiência , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologia
15.
Innate Immun ; 20(7): 760-73, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24179040

RESUMO

Although diminazene aceturate (Berenil) is widely used as a trypanolytic agent in livestock, its mechanisms of action remain poorly understood. We previously showed that Berenil treatment suppresses pro-inflammatory cytokine production by splenic and liver macrophages leading to a concomitant reduction in serum cytokine levels in mice infected with Trypanosoma congolense or challenged with LPS. Here, we investigated the molecular mechanisms through which Berenil alters pro-inflammatory cytokine production by macrophages. We show that pre-treatment of macrophages with Berenil dramatically suppressed IL-6, IL-12 and TNF-α production following LPS, CpG and Poly I:C stimulation without altering the expression of TLRs. Instead, it significantly down-regulated phosphorylation of mitogen-activated protein kinases (p38, extracellular signal-regulated kinase and c-Jun N-terminal kinases), signal transducer and activator of transcription (STAT) proteins (STAT1 and STAT3) and NF-кB p65 activity both in vitro and in vivo. Interestingly, Berenil treatment up-regulated the phosphorylation of STAT5 and the expression of suppressor of cytokine signaling 1 (SOCS1) and SOCS3, which are negative regulators of innate immune responses, including MAPKs and STATs. Collectively, these results show that Berenil down-regulates macrophage pro-inflammatory cytokine production by inhibiting key signaling pathways associated with cytokine production and suggest that this drug may be used to treat conditions caused by excessive production of inflammatory cytokines.


Assuntos
Citocinas/biossíntese , Diminazena/análogos & derivados , Inflamação/induzido quimicamente , Inflamação/metabolismo , Lipopolissacarídeos/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Fatores de Transcrição STAT/antagonistas & inibidores , Tripanossomicidas/toxicidade , Animais , Diminazena/toxicidade , Regulação para Baixo/efeitos dos fármacos , Feminino , Interleucina-6/biossíntese , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Quinases Ativadas por Mitógeno/metabolismo , NF-kappa B/metabolismo , Fosforilação/efeitos dos fármacos , Fatores de Transcrição STAT/metabolismo , Proteínas Supressoras da Sinalização de Citocina/antagonistas & inibidores , Receptores Toll-Like/biossíntese
16.
Shock ; 40(1): 65-73, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23635849

RESUMO

It is well established that CD4CD25 regulatory T cells (Tregs) downregulate inflammatory immune responses and help to maintain immune homeostasis. Recent reports have shown that ligation of germline encoded pattern recognition receptors such as Toll-like receptors can stimulate Tregs and therefore implicate Tregs in the pathophysiology of sepsis and other inflammatory diseases. In this report, we show that injection of lipopolysaccharide (LPS) leads to expansion of CD4CD25FoxP3 Tregs, suggesting that these cells may play an important role in immune regulation in LPS-induced acute inflammation. Indeed, genetic or immunological inhibition of Treg function using mice lacking functional Tregs (CD25 KO mice) or anti-CD25 monoclonal antibody (anti-CD25 mAb), respectively, led to acute death in an otherwise nonlethal LPS challenge. This was accompanied by exaggerated production of proinflammatory cytokines. Strikingly, adoptive transfer of CD4CD25 Tregs to CD25 KO mice before LPS challenge rescues mice from death. Unlike LPS, depletion of Tregs followed by concanavalin A (Con A) challenge does not result in mortality, suggesting that Treg depletion does not globally influence all models of acute inflammation. We authenticate our findings by showing that depletion of Tregs leads to mortality in a nonlethal Escherichia coli challenge accompanied by elevated serum levels of proinflammatory cytokines. Collectively, our results indicate that in addition to regulation of LPS-induced acute inflammation, Tregs help to improve bacterial clearance and promote survival in an acute model of bacterial infection.


Assuntos
Antígenos CD4/metabolismo , Infecções por Escherichia coli/imunologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Lipopolissacarídeos/toxicidade , Linfócitos T Reguladores/metabolismo , Linfócitos T Reguladores/fisiologia , Animais , Concanavalina A/farmacologia , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Síndrome de Resposta Inflamatória Sistêmica
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