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Antigenic inefficacy to induce robust immune responses and durable memory are major causes of constantly failing prophylactic approaches in leishmaniasis. Here, we determine the potential of a standardized whole-killed Leishmania vaccine (Leishvacc) adjuvanted with anti-CD200 and anti-CD300a antibodies, either alone or with monophosphoryl lipid A (MPL-SE) emulsified in squalene oil, in restoring the compromised antigen presenting abilities of dendritic cells (DCs), effector properties of CD4+T cells and providing protection against Leishmania donovani parasites. In animals vaccinated with antibodies adjuvanted vaccines, either alone or with MPL-SE, the antigen presenting abilities of CD11c+ DCs against Leishmania antigens, measured in terms of CD80, CD86, MHC-I, and MHC-II surface receptors and intracellular IL-12 were found enhanced than non-adjuvanted vaccine. We observed more proliferative and pro-inflammatory cytokines i.e. IL-2, IFN-γ, IL-23, and IL-12 producing CD4+T cells in antibodies/MPL-SE adjuvanted vaccinated animals further suggesting that this approach helps antigen activated CD4+T cells to acquire pro-inflammatory cytokines producing abilities. In antibodies, either alone or with MPL-SE, vaccinated animals, the number of CD4+ central memory T cells and their longevity were found significantly enhanced that further evidenced the impact of this vaccination approach in inducing long term protective immunity. The animals, receiving antibodies adjuvanted vaccines, either alone or with MPL-SE, exhibited excellent protection against virulent parasites by restricting their growth, which correlated with the significantly reduced parasitemia, splenomegaly, and hepatomegaly, along with fewer numbers of liver granulomas. Our findings provide an insight to a new immunoprophylactic approach against visceral leishmaniasis, which not only satisfies the safety criteria, but also provides a robust immunogenic response with remarkable potential for parasites control. However, further in-depth investigations are needed to ascertain its ability in inducing long-lasting immunity.
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BACKGROUND AND OBJECTIVES: Sensory neuronopathies (SNNs) are a rare group of pure sensory disorders causing asymmetrical, multifocal pattern of sensory loss with distinct clinical and electrophysiological features. We aimed to study the clinical features and etiology and share the experience of treating SNN from our center. METHODS: A prospective observational study was conducted over 3 years. Patients with predominant sensory complaints and electrophysiological evidence of neuropathy were evaluated. Possible/probable SNN was diagnosed using Camdessanch´e criteria. Detailed workup was done to determine the etiology and treatment given accordingly. Follow-up was done and response to treatment was assessed using modified Rankin Scale grading at 12 months. RESULTS: Fourteen patients with SNN were studied. Two (14.3%) patients were diagnosed with Sjogren's syndrome (SS-SNN), two (14.3%) with paraneoplastic syndrome, one (7.1%) with leprous ganglionitis, and nine (64.3%) were idiopathic sensory neuronopathy (I-SNN) cases. Improvement occurred in nine (64.3%), stability in three (21.4%), and worsening in two (14.3%) patients. Out of 11 SS-SNN and I-SNN patients, eight showed improvement on follow-up, seven with injection rituximab (RTX) and one with azathioprine. We found positive correlation between RTX treatment and improvement on follow-up ( P = 0.0256). Six (66.66%) out of nine I-SNN patients had early initiation of immunotherapy, of which all improved. There was positive correlation between early treatment initiation time in I-SNN patients and improvement ( P = 0.0119). CONCLUSIONS: Promising results were noted in SS-SNN and I-SNN patients with intensive treatment approach using RTX. Hit hard and early treatment approach is crucial for achieving improvement in sensory neuronopathies.
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Patients with hypoplastic left heart syndrome (HLHS) and its variants rely on the right ventricle (RV) to provide cardiac output. Diminished RV systolic function has been associated with poor clinical outcomes in this population. Echocardiographic strain has emerged as a useful method to quantify RV deformation. We aimed to describe fetal strain in the systemic RV and further investigate if there was any correlation with clinical outcomes. We conducted a retrospective, single center study evaluating strain in fetuses with systemic RV. We measured fetal RV global longitudinal strain (GLS) and segmental strain using Tomtec 2D speckle tracking software and compared these findings to controls. Fifty patients with systemic RV were included in the study group with controls matched one to one for each echocardiogram. Ten patients died after first-stage palliation. GLS was reproducible, with interobserver ICC 0.82. There was no statistically significant difference in GLS among different HLHS subtypes. Abnormal GLS did not correlate with worse clinical outcomes. GLS in systemic RVs in the 2nd and 3rd trimester did not vary significantly throughout gestation and did not correlate with clinical outcomes. Risk factors associated with poor outcome were mainly postnatal. Multi-centered studies are needed to determine if these findings hold true in a larger sample size.
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Populations can adapt to stressful environments through changes in gene expression. However, the role of gene regulation in mediating stress response and adaptation remains largely unexplored. Here, we use an integrative field dataset obtained from 780 plants of Oryza sativa ssp. indica (rice) grown in a field experiment under normal or moderate salt stress conditions to examine selection and evolution of gene expression variation under salinity stress conditions. We find that salinity stress induces increased selective pressure on gene expression. Further, we show that trans-eQTLs rather than cis-eQTLs are primarily associated with rice's gene expression under salinity stress, potentially via a few master-regulators. Importantly, and contrary to the expectations, we find that cis-trans reinforcement is more common than cis-trans compensation which may be reflective of rice diversification subsequent to domestication. We further identify genetic fixation as the likely mechanism underlying this compensation/reinforcement. Additionally, we show that cis- and trans-eQTLs are under different selection regimes, giving us insights into the evolutionary dynamics of gene expression variation. By examining genomic, transcriptomic, and phenotypic variation across a rice population, we gain insights into the molecular and genetic landscape underlying adaptive salinity stress responses, which is relevant for other crops and other stresses.
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Acute myeloid leukemia (AML) is fatal in the majority of adults. Identification of new therapeutic targets and their pharmacologic modulators are needed to improve outcomes. Previous studies had shown that immunization of rabbits with normal peripheral WBCs that had been incubated with fluorodinitrobenzene elicited high titer antibodies that bound to a spectrum of human leukemias. We report that proteomic analyses of immunoaffinity-purified lysates of primary AML cells showed enrichment of scaffolding protein IQGAP1. Immunohistochemistry and gene-expression analyses confirmed IQGAP1 mRNA overexpression in various cytogenetic subtypes of primary human AML compared to normal hematopoietic cells. shRNA knockdown of IQGAP1 blocked proliferation and clonogenicity of human leukemia cell-lines. To develop small molecules targeting IQGAP1 we performed in-silico screening of 212,966 compounds, selected 4 hits targeting the IQGAP1-GRD domain, and conducted SAR of the 'fittest hit' to identify UR778Br, a prototypical agent targeting IQGAP1. UR778Br inhibited proliferation, induced apoptosis, resulted in G2/M arrest, and inhibited colony formation by leukemia cell-lines and primary-AML while sparing normal marrow cells. UR778Br exhibited favorable ADME/T profiles and drug-likeness to treat AML. In summary, AML shows response to IQGAP1 inhibition, and UR778Br, identified through in-silico studies, selectively targeted AML cells while sparing normal marrow.
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Proliferação de Células , Leucemia Mieloide Aguda , Proteínas Ativadoras de ras GTPase , Humanos , Proteínas Ativadoras de ras GTPase/metabolismo , Proteínas Ativadoras de ras GTPase/genética , Proteínas Ativadoras de ras GTPase/antagonistas & inibidores , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Leucemia Mieloide Aguda/genética , Proliferação de Células/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Simulação por Computador , Antineoplásicos/farmacologia , Domínios Proteicos , Animais , Proteômica/métodosRESUMO
Forchlorfenuron (FCF) is a widely used plant cytokinin that enhances fruit quality and size in agriculture. It also serves as a crucial pharmacological tool for the inhibition of septins. However, the precise target of FCF has not yet been fully determined. This study reveals a novel target of FCF and elucidates its downstream signaling events. FCF significantly impairs mitochondrial respiration and mediates metabolic shift toward glycolysis, thus making cells more vulnerable to glycolysis inhibition. Interestingly, FCF's impact on mitochondrial function persists, even in cells lacking septins. Furthermore, the impaired mitochondrial function leads to the degradation of HIF-1α, facilitated by increased cellular oxygen. FCF also induces AMPK activation, suppresses Erk1/2 phosphorylation, and reduces the expression of HER2, ß-catenin, and PD-L1. Endometrial cancer is characterized by metabolic disorders such as diabetes and aberrant HER2/Ras-Erk1/2/ß-catenin signaling. Thus, FCF may hold promise as a potential therapeutic in endometrial cancer.
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Leishmania donovani are intracellular, human blood parasites that cause visceral leishmaniasis or kala-azar. Cell-penetrating peptides (CPPs) have been shown to modulate intracellular processes and cargo delivery, whereas host defense peptides (HDPs) promote proliferation of both naïve and antigen activated CD4+ T-cells. We report newly designed tripeptides that were able to trigger proinflammatory cytokine (IL-12 and IFN-γ) secretion by CD4+CD44+ T-cells in response to Leishmania donovani infection. These peptides can be used to induce antigen specific TH1 responses to combat obstacles of cytotoxicity and drug resistance associated with current anti-leishmanial drugs. Furthermore, these peptides can also be used as adjuvants to develop an effective immunoprophylactic approach for immunity restoration against visceral leishmaniasis.
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Leishmania donovani , Leishmaniose Visceral , Humanos , Interleucina-12 , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/parasitologia , Linfócitos T , Imunidade , Linfócitos T CD4-PositivosRESUMO
The all-terrain motility of lymphocytes in tissues and tissue-like gels is best described as amoeboid motility. For amoeboid motility, lymphocytes do not require specific biochemical or structural modifications to the surrounding extracellular matrix. Instead, they rely on changing shape and steric interactions with the microenvironment. However, the exact mechanism of amoeboid motility remains elusive. Here, we report that septins participate in amoeboid motility of T cells, enabling the formation of F-actin and α-actinin-rich cortical rings at the sites of cell cortex-indenting collisions with the extracellular matrix. Cortical rings compartmentalize cells into chains of spherical segments that are spatially conformed to the available lumens, forming transient "hourglass"-shaped steric locks onto the surrounding collagen fibers. The steric lock facilitates pressure-driven peristaltic propulsion of cytosolic content by individually contracting cell segments. Our results suggest that septins provide microenvironment-guided partitioning of actomyosin contractility and steric pivots required for amoeboid motility of T cells in tissue-like microenvironments.
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Actomiosina , Amoeba , Actomiosina/metabolismo , Septinas/metabolismo , Movimento Celular , Amoeba/metabolismo , Linfócitos T/metabolismoRESUMO
BACKGROUND: The Pediatric Heart Transplant Society (PHTS) Registry was founded 30 years ago as a collaborative effort among like-minded providers of this novel life-saving technique for children with end-stage heart failure. In the intervening decades, the data from the Registry have provided invaluable knowledge to the field of pediatric heart transplantation. This report of the PHTS Registry provides a comprehensive look at the data, highlighting both the longevity of the registry and one unique aspect of the PHTS registry, allowing for exploration into children with single ventricle anatomy. METHODS: The PHTS database was queried from January 1, 1993 to December 31, 2019 to include pediatric (age < 18 years) patients listed for HT. For our analysis, we primarily analyzed patients by era. The early era was defined as children listed for HT from January 1, 1993 to December 31, 2004; middle era January 1, 2005 to December 31, 2009; and recent era January 1, 2010 to December 31, 2019. Outcomes after listing and transplant, including mortality and morbidities, are presented as unadjusted for risk, but compared across eras. RESULTS: Since 1993, 11 995 children were listed for heart transplant and entered into the PHTS Registry with 9755 listed during the study period. The majority of listings occurred within the most recent era. Waitlist survival improved over the decades as did posttransplant survival. Other notable changes over time include fewer patients experiencing allograft rejection or infection after transplant. Waitlist and posttransplant survival have changed dramatically in patients with single ventricle physiology and significantly differ by stage of single ventricle palliation. SUMMARY: Key points from this PHTS Registry summary and focus on patients with single ventricle congenital heart disease in particular, include the changing landscape of candidates and recipients awaiting heart transplant. There is clear improvement in waitlist and transplant outcomes for children with both cardiomyopathy and congenital heart disease alike.
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Cardiomiopatias , Cardiopatias Congênitas , Transplante de Coração , Coração Univentricular , Criança , Humanos , Adolescente , Dados de Saúde Coletados Rotineiramente , Cardiopatias Congênitas/cirurgia , Sistema de Registros , Listas de Espera , Estudos RetrospectivosRESUMO
In leishmaniasis, the protective immunity is largely mediated by proinflammatory cytokine producing abilities of T cells and an efficient parasite killing by phagocytic cells. Notwithstanding a substantial progress that has been made during last decades, the mechanisms or factors involved in establishing protective immunity against Leishmania are not identified. In ancient Indian literature, metallic "bhasma," particularly that of "swarna" or gold (fine gold particles), is indicated as one of the most prominent metal-based therapeutic medicine, which is known to impart protective and curative properties in various health issues. In this work, we elucidated the potential of swarna bhasma (SB) on the effector properties of phagocytes and antigen-activated CD4+ T cells in augmenting the immunogenicity of L. donovani antigens. The characterization of SB revealing its shape, size, composition, and measurement of cytotoxicity established the physiochemical potential for its utilization as an immunomodulator. The activation of macrophages with SB enhanced their capacity to produce nitric oxide and proinflammatory cytokines, which eventually resulted in reduced uptake of parasites and their proliferation in infected cells. Further, in Leishmania-infected animals, SB administration reduced the generation of IL-10, an anti-inflammatory cytokine, and enhanced pro-inflammatory cytokine generation by antigen activated CD4+ T cells with increased frequency of double (IFNγ+/TNFα+) and triple (IFNγ+TNFα+IL-2+) positive cells and abrogated disease pathogeneses at the early days of infection. Our results also suggested that cow-ghee (A2) emulsified preparation of SB, either alone or with yashtimadhu, a known natural immune modulator which enhances the SB's potential in enhancing the immunogenicity of parasitic antigens. These findings suggested a definite potential of SB in enhancing the effector functions of phagocytes and CD4+ T cells against L. donovani antigens. Therefore, more studies are needed to elucidate the mechanistic details of SB and its potential in enhancing vaccine-induced immunity.
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Apresentação de Antígeno , Antígenos de Protozoários , Linfócitos T CD4-Positivos , Calotropis , Ouro , Látex , Leishmania donovani , Macrófagos , Ayurveda , Células Th1 , Arsênio , Combinação de Medicamentos , Ouro/administração & dosagem , Ouro/farmacologia , Látex/administração & dosagem , Látex/farmacologia , Chumbo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Linfócitos T CD4-Positivos/imunologia , Fagócitos/efeitos dos fármacos , Fagócitos/imunologia , Leishmaniose/imunologia , Leishmaniose/parasitologia , Leishmania donovani/efeitos dos fármacos , Leishmania donovani/crescimento & desenvolvimento , Leishmania donovani/imunologia , Antígenos de Protozoários/imunologia , Células Th1/imunologia , Animais , Camundongos , Células RAW 264.7 , Feminino , Camundongos Endogâmicos BALB CRESUMO
The excessive production of IL-10, an anti-inflammatory cytokine, by Leishmania antigen-activated T cells is supposed to be a key player in the onset and progression of visceral leishmaniasis (VL). The IL-10-producing sources in VL remain unidentified and uncharacterized. In this study, we reveal that antigen-activated CD4+ T cells, i.e., CD44+CD4+ T cells expressing CD200R receptors, are the prime IL-10-producing phenotypes in Leishmania donovani infection-induced pathogenesis. These phenotypes are separate from CD25+Foxp3+CD4+ T regulatory cells, which are classical IL-10-producing phenotypes. In order to ascertain the role of CD200R and CD25 receptors in IL-10 overexpression-associated VL pathogenesis, we abrogated CD200R and CD25 receptor-mediated signaling in the infected mice. The splenic load of parasites and the size of the liver and spleen were significantly reduced in CD200-blocked mice as compared to CD25-blocked mice. Further, the CD200 blocking polarized CD4+ T cells to pro-inflammatory cytokines-producing phenotypes, as we observed a higher frequency of IFN-γ, TNF-α, and IL-12 positive cells as compared to controls including the CD25 blocking. Our findings suggest that in L. donovani infection-induced pathogenesis the expression of CD200R on antigen-activated T cells helps them to acquire IL-10-producing abilities as part of its one of the survival strategies. However, more studies would be warranted to better understand CD200R receptors role in VL pathogenesis and to develop the next generation of therapeutic and prophylactic control measures.
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Leishmania donovani , Leishmaniose Visceral , Animais , Camundongos , Interleucina-10/metabolismo , Citocinas/metabolismo , Linfócitos T Reguladores , FenótipoRESUMO
Objective This study aims to evaluate the effect of inferior turbinate reduction on middle ear compliance and pressure. Methods A prospective observational study was conducted on 100 patients between 20 and 60 years of age with bilateral nasal obstruction due to inferior turbinate hypertrophy and a normal-looking external and middle ear. The Wilcoxon signed-rank test with a 95% confidence interval was used to compare the middle ear peak compliance and pressure on tympanometry before and one month after the inferior turbinate reduction surgery. Results The mean age was 28.44 ± 8.23 years, with a male/female ratio of 7:3. After surgery, patients with normal compliance increased by 8%, high compliance decreased by 12%, and low compliance increased by 4% in the right ear. High compliance decreased by 2%, normal compliance decreased by 10%, and low compliance increased by 12% in the left ear. Positive tympanometric peak pressure (TPP) increased by 37% and 43% in the right and left ears, respectively. Conclusion After turbinate reduction surgery, the overall tympanometric peak pressure and compliance improved. However, we did not see an obvious improvement in low middle ear compliance. Thus, turbinate reduction surgery might benefit patients with inferior turbinate hypertrophy and associated poor middle ear ventilation.
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Carrageenan, a polysaccharide derived from red algae, has a long history of use as a food additive in food. Carrageenan comes in three classes, κ-, ι-, and λ-carrageenan, with different properties attributed to their organosulfate substitution levels, and their interactions with other food components give rise to properties such as water holding, thickening, gelling, and stabilizing. Over the years, carrageenan has been used in wide variety of food products such as meat, dairy, and flour-based products, and their mechanisms and functions in these matrices have also been studied. With the emergence of novel food technologies, carrageenan's potential applications have been extensively explored alongside, including encapsulation, edible films/coatings, plant-based analogs, and 3D/4D printing. As the food technology evolves, the required functions of food ingredients have changed, and carrageenan is being investigated for its role in these new areas. However, there are many similarities in the use of carrageenan in both classic and emerging applications, and understanding the underlying principles of carrageenan will lead to a proper use of carrageenan in emerging food products. This review focuses on the potential of carrageenan as a food ingredient in these emerging technologies mainly based on papers published within the past five years, highlighting its functions and applications to better understand its role in food products.
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Aditivos Alimentares , Polissacarídeos , Carragenina , Alimentos , Tecnologia de AlimentosRESUMO
One of the major reasons behind the limited success of vaccine candidates against all forms of leishmaniasis is the inability of parasitic antigens to induce robust cell-mediated immunity and immunological memory. Here we find, for the first time, that the adjuvantation of whole-killed Leishmania vaccine (Leishvacc) with anti-CD200 and anti-CD300a antibodies enhances CD4+ T cells mediated immunity in vaccinated mice and provides protection against wild-type parasites. The antibody adjuvantation, either alone or with a TLR4 agonist monophosphoryl A (MPL-A), induced the production of pro-inflammatory cytokines viz., IFN-γ, TNF-α, and IL-2 by antigen experienced CD4+ T cells, and also enhanced their rate of conversion into their memory phenotypes against Leishvacc antigens. The antibody adjuvanted vaccine also promoted the generation of IgG2a-mediated protective humoral immunity in vaccinated mice. Further, the mice vaccinated with antibodies adjuvanted vaccine showed strong resilience against metacyclic forms of L. donovani parasites as we observed reduced clinical features such as splenomegaly, hepatomegaly, granulomatous tissues in the liver, and parasitic load in their spleen. The findings of this study demonstrate that the anti-CD200 and anti-CD300a antibodies have potential to increase the protective efficacy of the whole-killed Leishmania vaccine, and opens up a new gateway to diversify the roles of immune checkpoints in vaccine development against leishmaniasis.
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Leishmania donovani , Leishmania , Vacinas contra Leishmaniose , Leishmaniose Visceral , Leishmaniose , Parasitos , Animais , Camundongos , Vacinas de Produtos Inativados , Adjuvantes Imunológicos/farmacologia , Leishmaniose/prevenção & controle , Camundongos Endogâmicos BALB C , Antígenos de ProtozoáriosRESUMO
Lymphocytes exit circulation and enter in-tissue guided migration toward sites of tissue pathologies, damage, infection, or inflammation. By continuously sensing and adapting to the guiding chemo-mechano-structural properties of the tissues, lymphocytes dynamically alternate and combine their amoeboid (non-adhesive) and mesenchymal (adhesive) migration modes. However, which mechanisms guide and balance different migration modes are largely unclear. Here we report that suppression of septins GTPase activity induces an abrupt amoeboid-to-mesenchymal transition of T cell migration mode, characterized by a distinct, highly deformable integrin-dependent immune cell contact guidance. Surprisingly, the T cell actomyosin cortex contractility becomes diminished, dispensable and antagonistic to mesenchymal-like migration mode. Instead, mesenchymal-like T cells rely on microtubule stabilization and their non-canonical dynein motor activity for high fidelity contact guidance. Our results establish septin's GTPase activity as an important on/off switch for integrin-dependent migration of T lymphocytes, enabling their dynein-driven fluid-like mesenchymal propulsion along the complex adhesion cues.
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Cold plasma processing is a non-thermal food processing technique that has been shown to improve the gelling properties of plant proteins by altering their structure through oxidation and crosslinking. This study aimed to investigate the effects of cold plasma treatment on the rheological properties of skim milk under different conditions, focusing on the impact of feed gas and treatment time on skim milk's sulfhydryl content, flow properties, and acid gelling behavior. Results showed that free sulfhydryl content decreased with treatment time, with a notable reduction observed after 2 min of N2-O2 plasma treatment. Skim milk treated with N2 plasma experienced a more gradual decrease in free SH content. Cold plasma increased skim milk viscosity over time. N2-O2 plasma treatment significantly affected G'40 and G'4 storage moduli, with an increase observed after 2 min of exposure but no change beyond that time. Acid gels' greenness (a* value) decreased with increasing treatment time compared to the control. Acid gel firmness of milk treated with N2-O2 plasma for 1 min significantly increased from 1.804 N to 1.912 N, and further to 2.072 N after 2 min of treatment. However, longer exposure times led to lower firmness in gels. N2 plasma treatment also significantly impacted acid gel firmness. Syneresis in acid gels decreased from 63.4 % to 57.7 % and 58.7 % after 1 and 2 min of N2-O2 plasma treatment, respectively, but increased to about 70 % after 4 min. Acid gels made from milk treated with N2 plasma experienced considerably less syneresis. The cold plasma treatment under different conditions significantly affected the properties of skim milk, with various impacts on sulfhydryl content, flow properties, and acid gelling behavior. These findings demonstrate the potential applications of cold plasma processing in the food industry to improve product properties.
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Leite , Gases em Plasma , Animais , Manipulação de Alimentos , Reologia , Compostos de SulfidrilaRESUMO
The principal cause of death in cancer patients is metastasis, which remains an unresolved problem. Conventionally, metastatic dissemination is linked to actomyosin-driven cell locomotion. However, the locomotion of cancer cells often does not strictly line up with the measured actomyosin forces. Here, a complementary mechanism of metastatic locomotion powered by dynein-generated forces is identified. These forces arise within a non-stretchable microtubule network and drive persistent contact guidance of migrating cancer cells along the biomimetic collagen fibers. It is also shown that the dynein-powered locomotion becomes indispensable during invasive 3D migration within a tissue-like luminal network formed by spatially confining granular hydrogel scaffolds (GHS) made up of microscale hydrogel particles (microgels). These results indicate that the complementary motricity mediated by dynein is always necessary and, in certain instances, sufficient for disseminating metastatic breast cancer cells. These findings advance the fundamental understanding of cell locomotion mechanisms and expand the spectrum of clinical targets against metastasis.
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Neoplasias da Mama , Dineínas , Humanos , Feminino , Dineínas/metabolismo , Actomiosina/metabolismo , Movimento Celular , HidrogéisRESUMO
Small-molecule inhibitors of PD-L1 are postulated to control immune evasion in tumors similar to antibodies that target the PD-L1/PD-1 immune checkpoint axis. However, the identity of targetable PD-L1 inducers is required to develop small-molecule PD-L1 inhibitors. In this study, using chromatin immunoprecipitation (ChIP) assay and siRNA, we demonstrate that vitamin D/VDR regulates PD-L1 expression in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) cells. We have examined whether a VDR antagonist, MeTC7, can inhibit PD-L1. To ensure that MeTC7 inhibits VDR/PD-L1 without off-target effects, we examined competitive inhibition of VDR by MeTC7, utilizing ligand-dependent dimerization of VDR-RXR, RXR-RXR, and VDR-coactivators in a mammalian 2-hybrid (M2H) assay. MeTC7 inhibits VDR selectively, suppresses PD-L1 expression sparing PD-L2, and inhibits the cell viability, clonogenicity, and xenograft growth of AML cells. MeTC7 blocks AML/mesenchymal stem cells (MSCs) adhesion and increases the efferocytotic efficiency of THP-1 AML cells. Additionally, utilizing a syngeneic colorectal cancer model in which VDR/PD-L1 co-upregulation occurs in vivo under radiation therapy (RT), MeTC7 inhibits PD-L1 and enhances intra-tumoral CD8+T cells expressing lymphoid activation antigen-CD69. Taken together, MeTC7 is a promising small-molecule inhibitor of PD-L1 with clinical potential.
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Bacille Calmette-Guérin (BCG) vaccination supposedly imparts and augments "trained immunity" that cross-protects against multiple unrelated pathogens and enhances general immune surveillance. Gradual reductions in tuberculosis burden over the last 3-5 decades have resulted in the withdrawal of BCG vaccination mandates from developed industrialized countries while reducing to a single neonatal shot in the rest. Concurrently, a steady increase in early childhood Brain and CNS (BCNS) tumors has occurred. Though immunological causes of pediatric BCNS cancer are suspected, the identification of a causal protective variable with intervention potential has remained elusive. An examination of the countries with contrasting vaccination policies indicates significantly lower BCNS cancer incidence in 0-4-year-olds (per hundredthousand) of countries following neonatal BCG inoculations (n=146) vs. non-BCG countries (n=33) [Mean: 1.26 vs. 2.64; Median: 0.985 vs. 2.8; IQR: 0.31-2.0 vs. 2.4-3.2; P=<0.0001 (two-tailed)]. Remarkably, natural Mycobacterium spp. reexposure likelihood is negatively correlated with BCNS cancer incidence in 0-4-year-olds of all affected countries [r(154): -0.6085, P=<0.0001]. Seemingly, neonatal BCG vaccination and natural "boosting" are associated with a 15-20-fold lower BCNS cancer incidence. In this opinion article, we attempt to synthesize existing evidence implying the immunological basis of early childhood BCNS cancer incidence and briefly indicate possible causes that could have precluded objective analysis of the existing data in the past. We draw the attention of the stakeholders to consider the comprehensive evaluation of immune training as a potential protective variable through well-designed controlled clinical trials or registry-based studies as feasible for its potential applications in reducing childhood BCNS cancer incidence.
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Encéfalo , Neoplasias do Sistema Nervoso Central , Pré-Escolar , Recém-Nascido , Humanos , Criança , Incidência , Políticas , VacinaçãoRESUMO
Preventive variables for childhood leukemia incidence (LI) remain unknown. Past assertions that childhood vaccinations, especially BCG, may be potentially protective have remained disputed for over five decades because of the lack of a unifying framework to explain variable outcomes in different studies. An examination of the early childhood LI for 2020 in European Region countries with supposedly similar underlying confounders but differential childhood vaccination coverage displays negative covariation with prevailing Mycobacterium spp. exposure in BCG-vaccinated children. The childhood LI in 0-4-year-old populations with >90% childhood BCG vaccination coverage is found to be strongly but negatively correlated with prevailing tuberculin immunoreactivity [r(24): -0.7868, p-value: < 0.0001]. No such correlation existed for the LI in 0-4-year-old populations without BCG vaccinations, though weak associations are hinted at by the available data for MCV2, PCV3, and DTP3 vaccinations. We hypothesize that early childhood BCG vaccination "priming" and subsequent "trained immunity" augmentation by "natural" boosting from Mycobacterium spp. exposure play a preventive and protective role in childhood LI. The non-consideration of prevailing "trained immunity" could have been a cause behind the conflicting outcomes in past studies. Exploratory studies, preferably performed in high-burden countries and controlling for the trained-immunity correlate and other potential confounders, would be warranted in order to establish a role for BCG vaccination and early-life immune training (or lack thereof) in childhood LI and help put the current controversy to rest.