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1.
Mol Divers ; 2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38460065

RESUMO

Contemporary research has convincingly demonstrated that upregulation of G protein-coupled receptor 183 (GPR183), orchestrated by its endogenous agonist, 7α,25-dihydroxyxcholesterol (7α,25-OHC), leads to the development of cancer, diabetes, multiple sclerosis, infectious, and inflammatory diseases. A recent study unveiled the cryo-EM structure of 7α,25-OHC bound GPR183 complex, presenting an untapped opportunity for computational exploration of potential GPR183 inhibitors, which served as our inspiration for the current work. A predictive and validated two-dimensional QSAR model using genetic algorithm (GA) and multiple linear regression (MLR) on experimental GPR183 inhibition data was developed. QSAR study highlighted that structural features like dissimilar electronegative atoms, quaternary carbon atoms, and CH2RX fragment (X: heteroatoms) influence positively, while the existence of oxygen atoms with a topological separation of 3, negatively affects GPR183 inhibitory activity. Post assessment of true external set prediction capability, the MLR model was deployed to screen 12,449 DrugBank compounds, followed by a screening pipeline involving molecular docking, druglikeness, ADMET, protein-ligand stability assessment using deep learning algorithm, molecular dynamics, and molecular mechanics. The current findings strongly evidenced DB05790 as a potential lead for prospective interference of oxysterol-mediated GPR183 overexpression, warranting further in vitro and in vivo validation.

2.
Nucleic Acids Res ; 50(7): 3985-3997, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35357498

RESUMO

Yersinia phage YerA41 is morphologically similar to jumbo bacteriophages. The isolated genomic material of YerA41 could not be digested by restriction enzymes, and used as a template by conventional DNA polymerases. Nucleoside analysis of the YerA41 genomic material, carried out to find out whether this was due to modified nucleotides, revealed the presence of a ca 1 kDa substitution of thymidine with apparent oligosaccharide character. We identified and purified the phage DNA polymerase (DNAP) that could replicate the YerA41 genomic DNA even without added primers. Cryo-electron microscopy (EM) was used to characterize structural details of the phage particle. The storage capacity of the 131 nm diameter head was calculated to accommodate a significantly longer genome than that of the 145 577 bp genomic DNA of YerA41 determined here. Indeed, cryo-EM revealed, in contrast to the 25 Å in other phages, spacings of 33-36 Å between shells of the genomic material inside YerA41 heads suggesting that the heavily substituted thymidine increases significantly the spacing of the DNA packaged inside the capsid. In conclusion, YerA41 appears to be an unconventional phage that packages thymidine-modified genomic DNA into its capsids along with its own DNAP that has the ability to replicate the genome.


Assuntos
Bacteriófagos , Bacteriófagos/química , Bacteriófagos/genética , Capsídeo , Microscopia Crioeletrônica , DNA Viral/genética , DNA Polimerase Dirigida por DNA/genética , Genoma Viral/genética , Timidina
3.
BMC Public Health ; 22(1): 1363, 2022 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-35842623

RESUMO

BACKGROUND: The number of food banks (charitable outlets of emergency food parcels) and the volume of food distributed by them increased multi-fold in the United Kingdom (UK) since 2010. The overwhelming majority of users of food banks are severely food insecure. Since food insecurity implies a nutritionally inadequate diet, and poor dietary intake has been linked to a number of diseases and chronic conditions, the rise in the number of people using food banks is a phenomenon of significant importance for public health. However, there is a shortage of robust, causal statistical analyses of drivers of food bank use, hindering social and political action on alleviating severe food insecurity. METHODS: A panel dataset of 325 local authorities in England was constructed, spanning 9 years (2011/12-2019/20). The dataset included information about the volume of parcels and the number of food banks in the Trussell Trust network, as well as economy-related, welfare system-related and housing-related variables. A quasi-experimental approach was employed in the form of a 'first differencing' ecological model, predicting the number of food parcels distributed by food banks in the Trussell Trust network. This neutralised bias from omitting time-constant unobserved confounders. RESULTS: Seven predictors in the model were statistically significant, including four related to the welfare system: the value of the main out-of-work benefit; the roll-out of Universal Credit; benefit sanctions; and the 'bedroom tax' in social housing. Of the remaining three significant predictors, one regarded the 'supply' side (the number of food banks in the area) and two regarded the 'demand' side (the proportion of working age population on out-of-work benefits; the proportion of working age population who were unemployed). CONCLUSION: The structure of the welfare system has been partly responsible for driving food bank use in the UK since 2011. Severe food insecurity could be alleviated by reforming aspects of the benefit system that have been evidenced to be implicated in the rise in food bank use. More broadly, the findings provide support for 'Health and Health Equity in All Policies' approach to policymaking.


Assuntos
Assistência Alimentar , Abastecimento de Alimentos , Inglaterra , Alimentos , Humanos , Políticas , Seguridade Social
4.
J Biol Chem ; 290(15): 9500-10, 2015 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-25659429

RESUMO

Atypical hemolytic uremic syndrome (aHUS) is characterized by complement attack against host cells due to mutations in complement proteins or autoantibodies against complement factor H (CFH). It is unknown why nearly all patients with autoimmune aHUS lack CFHR1 (CFH-related protein-1). These patients have autoantibodies against CFH domains 19 and 20 (CFH19-20), which are nearly identical to CFHR1 domains 4 and 5 (CFHR14-5). Here, binding site mapping of autoantibodies from 17 patients using mutant CFH19-20 constructs revealed an autoantibody epitope cluster within a loop on domain 20, next to the two buried residues that are different in CFH19-20 and CFHR14-5. The crystal structure of CFHR14-5 revealed a difference in conformation of the autoantigenic loop in the C-terminal domains of CFH and CFHR1, explaining the variation in binding of autoantibodies from some aHUS patients to CFH19-20 and CFHR14-5. The autoantigenic loop on CFH seems to be generally flexible, as its conformation in previously published structures of CFH19-20 bound to the microbial protein OspE and a sialic acid glycan is somewhat altered. Cumulatively, our data suggest that association of CFHR1 deficiency with autoimmune aHUS could be due to the structural difference between CFHR1 and the autoantigenic CFH epitope, suggesting a novel explanation for CFHR1 deficiency in the pathogenesis of autoimmune aHUS.


Assuntos
Autoanticorpos/química , Proteínas Inativadoras do Complemento C3b/química , Fator H do Complemento/química , Epitopos/química , Síndrome Hemolítico-Urêmica Atípica/genética , Síndrome Hemolítico-Urêmica Atípica/imunologia , Síndrome Hemolítico-Urêmica Atípica/metabolismo , Autoanticorpos/imunologia , Autoimunidade/genética , Autoimunidade/imunologia , Sítios de Ligação/genética , Sítios de Ligação/imunologia , Proteínas Inativadoras do Complemento C3b/genética , Proteínas Inativadoras do Complemento C3b/imunologia , Fator H do Complemento/genética , Fator H do Complemento/imunologia , Cristalografia por Raios X , Mapeamento de Epitopos , Epitopos/imunologia , Humanos , Modelos Moleculares , Mutação , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , Ligação Proteica/imunologia , Estrutura Terciária de Proteína
5.
J Biol Chem ; 288(26): 18685-95, 2013 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-23658013

RESUMO

Borrelia burgdorferi spirochetes that cause Lyme borreliosis survive for a long time in human serum because they successfully evade the complement system, an important arm of innate immunity. The outer surface protein E (OspE) of B. burgdorferi is needed for this because it recruits complement regulator factor H (FH) onto the bacterial surface to evade complement-mediated cell lysis. To understand this process at the molecular level, we used a structural approach. First, we solved the solution structure of OspE by NMR, revealing a fold that has not been seen before in proteins involved in complement regulation. Next, we solved the x-ray structure of the complex between OspE and the FH C-terminal domains 19 and 20 (FH19-20) at 2.83 Å resolution. The structure shows that OspE binds FH19-20 in a way similar to, but not identical with, that used by endothelial cells to bind FH via glycosaminoglycans. The observed interaction of OspE with FH19-20 allows the full function of FH in down-regulation of complement activation on the bacteria. This reveals the molecular basis for how B. burgdorferi evades innate immunity and suggests how OspE could be used as a potential vaccine antigen.


Assuntos
Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Borrelia burgdorferi/imunologia , Fator H do Complemento/imunologia , Lipoproteínas/imunologia , Doença de Lyme/microbiologia , Sequência de Aminoácidos , Sítios de Ligação , Cristalografia por Raios X , Células Endoteliais/metabolismo , Glicosaminoglicanos/metabolismo , Humanos , Ligação de Hidrogênio , Imunidade Inata , Doença de Lyme/imunologia , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Homologia de Sequência de Aminoácidos
6.
Proc Natl Acad Sci U S A ; 108(7): 2897-902, 2011 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21285368

RESUMO

The alternative pathway of complement is important in innate immunity, attacking not only microbes but all unprotected biological surfaces through powerful amplification. It is unresolved how host and nonhost surfaces are distinguished at the molecular level, but key components are domains 19-20 of the complement regulator factor H (FH), which interact with host (i.e., nonactivator surface glycosaminoglycans or sialic acids) and the C3d part of C3b. Our structure of the FH19-20:C3d complex at 2.3-Å resolution shows that FH19-20 has two distinct binding sites, FH19 and FH20, for C3b. We show simultaneous binding of FH19 to C3b and FH20 to nonactivator surface glycosaminoglycans, and we show that both of these interactions are necessary for full binding of FH to C3b on nonactivator surfaces (i.e., for target discrimination). We also show that C3d could replace glycosaminoglycan binding to FH20, thus providing a feedback control for preventing excess C3b deposition and complement amplification. This explains the molecular basis of atypical hemolytic uremic syndrome, where mutations on the binding interfaces between FH19-20 and C3d or between FH20 and glycosaminoglycans lead to complement attack against host surfaces.


Assuntos
Complemento C3d/metabolismo , Fator H do Complemento/metabolismo , Via Alternativa do Complemento/imunologia , Glicosaminoglicanos/metabolismo , Imunidade Inata/imunologia , Análise de Variância , Síndrome Hemolítico-Urêmica Atípica , Sítios de Ligação , Cromatografia de Afinidade , Complemento C3d/genética , Complemento C3d/imunologia , Fator H do Complemento/genética , Fator H do Complemento/imunologia , Cristalização , Cristalografia por Raios X , Primers do DNA/genética , Escherichia coli , Glicosaminoglicanos/genética , Glicosaminoglicanos/imunologia , Síndrome Hemolítico-Urêmica/imunologia , Humanos , Mutagênese Sítio-Dirigida , Pichia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ressonância de Plasmônio de Superfície
7.
Int J Biol Macromol ; 269(Pt 1): 131784, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38697440

RESUMO

GRK5 holds a pivotal role in cellular signaling pathways, with its overexpression in cardiomyocytes, neuronal cells, and tumor cells strongly associated with various chronic degenerative diseases, which highlights the urgent need for potential inhibitors. In this study, multiclass classification-based QSAR models were developed using diverse machine learning algorithms. These models were built from curated compounds with experimentally derived GRK5 inhibitory activity. Additionally, a pharmacophore model was constructed using active compounds from the dataset. Among the models, the SVM-based approach proved most effective and was initially used to screen DrugBank compounds within the applicability domain. Compounds showing significant GRK5 inhibitory potential underwent evaluation for key pharmacophoric features. Prospective compounds were subjected to molecular docking to assess binding affinity towards GRK5's key active site amino acid residues. Stability at the binding site was analyzed through 200 ns molecular dynamics simulations. MM-GBSA analysis quantified individual free energy components contributing to the total binding energy with respect to binding site residues. Metadynamics analysis, including PCA, FEL, and PDF, provided crucial insights into conformational changes of both apo and holo forms of GRK5 at defined energy states. The study identifies DB02844 (S-Adenosyl-1,8-Diamino-3-Thiooctane) and DB13155 (Esculin) as promising GRK5 inhibitors, warranting further in vitro and in vivo validation studies.


Assuntos
Quinase 5 de Receptor Acoplado a Proteína G , Aprendizado de Máquina , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Inibidores de Proteínas Quinases , Relação Quantitativa Estrutura-Atividade , Quinase 5 de Receptor Acoplado a Proteína G/antagonistas & inibidores , Quinase 5 de Receptor Acoplado a Proteína G/metabolismo , Quinase 5 de Receptor Acoplado a Proteína G/química , Ligantes , Humanos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Termodinâmica , Ligação Proteica , Sítios de Ligação , Doença Crônica , Farmacóforo
8.
Cell Chem Biol ; 31(3): 593-606.e9, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38039968

RESUMO

Cerebral dopamine neurotrophic factor (CDNF) is an unconventional neurotropic factor that modulates unfolded protein response (UPR) pathway signaling and alleviates endoplasmic reticulum (ER) stress providing cytoprotective effects in different models of neurodegenerative disorders. Here, we developed a brain-penetrating peptidomimetic compound based on human CDNF. This compound called HER-096 shows similar potency and mechanism of action as CDNF, and promotes dopamine neuron survival, reduces α-synuclein aggregation and modulates UPR signaling in in vitro models. HER-096 is metabolically stable and able to penetrate to cerebrospinal (CSF) and brain interstitial fluids (ISF) after subcutaneous administration, with an extended CSF and brain ISF half-life compared to plasma. Subcutaneously administered HER-096 modulated UPR pathway activity, protected dopamine neurons, and reduced α-synuclein aggregates and neuroinflammation in substantia nigra of aged mice with synucleinopathy. Peptidomimetic HER-096 is a candidate for development of a disease-modifying therapy for Parkinson's disease with a patient-friendly route of administration.


Assuntos
Doença de Parkinson , Peptidomiméticos , Sinucleinopatias , Humanos , Camundongos , Animais , Doença de Parkinson/tratamento farmacológico , Neurônios Dopaminérgicos , alfa-Sinucleína , Peptidomiméticos/farmacologia , Peptidomiméticos/uso terapêutico , Encéfalo , Fatores de Crescimento Neural
9.
J Hazard Mater ; 480: 136110, 2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39405699

RESUMO

The increasing presence of active pharmaceutical ingredients (APIs) in aquatic ecosystems, driven by widespread human use, poses significant risks, including acute and chronic toxicity to aquatic species. However, the scarcity of experimental toxicity data on APIs and related compounds due to the high costs, time requirements, and ethical concerns associated with animal testing hinders comprehensive risk assessment. In response, we developed quantitative structure-toxicity relationship (QSTR) and interspecies quantitative structure toxicity-toxicity relationship (i-QSTTR) models for three key aquatic species: zebrafish, water fleas, and green algae, using NOEC as an endpoint, following OECD guidelines. Algae, daphnia, and fish, recognized as standard organisms in toxicity testing, are crucial bio-indicators due to their size, transparency, adaptability, and regulatory acceptance. We used partial least squares (PLS) and multiple linear regression (MLR) methods for model development alongside machine learning techniques such as Random Forest (RF), Support Vector Machines (SVM), K-nearest Neighbor (kNN), and Neural Networks (NN) to enhance the predictivity. Lipophilicity, electronegativity, unsaturation, a molecular cyclized degree in molecular structure, large fragments, aliphatic secondary C(sp2), and R-CR-R groups were identified as critical biomarkers for API toxicity. Screening of the PPDB (pesticide properties databases) and DrugBank validated the practical application of these models, offering valuable tools for regulatory decisions, safer API design, and the preservation of aquatic biodiversity.

10.
Nat Commun ; 15(1): 8175, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39289391

RESUMO

Cerebral dopamine neurotrophic factor (CDNF) is an unconventional neurotrophic factor that is a disease-modifying drug candidate for Parkinson's disease. CDNF has pleiotropic protective effects on stressed cells, but its mechanism of action remains incompletely understood. Here, we use state-of-the-art advanced structural techniques to resolve the structural basis of CDNF interaction with GRP78, the master regulator of the unfolded protein response (UPR) pathway. Subsequent binding studies confirm the obtained structural model of the complex, eventually revealing the interaction site of CDNF and GRP78. Finally, mutating the key residues of CDNF mediating its interaction with GRP78 not only results in impaired binding of CDNF but also abolishes the neuroprotective activity of CDNF-derived peptides in mesencephalic neuron cultures. These results suggest that the molecular interaction with GRP78 mediates the neuroprotective actions of CDNF and provide a structural basis for development of next generation CDNF-based therapeutic compounds against neurodegenerative diseases.


Assuntos
Chaperona BiP do Retículo Endoplasmático , Proteínas de Choque Térmico , Resposta a Proteínas não Dobradas , Chaperona BiP do Retículo Endoplasmático/metabolismo , Humanos , Proteínas de Choque Térmico/metabolismo , Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/genética , Animais , Ligação Proteica , Fatores de Crescimento Neural/metabolismo , Fatores de Crescimento Neural/química , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/metabolismo , Neurônios/metabolismo , Modelos Moleculares , Sítios de Ligação
11.
Cureus ; 16(6): e61978, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38855498

RESUMO

Background Treatment of metastatic renal cell cancer (mRCC) has revolutionized with the introduction of anti-VEGF tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs). There is limited data in the literature on the outcomes of Indian patients treated with TKI. Here, we report the outcome of mRCC treated with first-line TKI in a resource-poor setting. Material and methods This is a single-center retrospective study of clear cell mRCC treated with first-line TKI from June 2012 to December 2022. Demographic characteristics and treatment details, including outcome data, were captured from electronic medical records. Patients who received at least one week of therapy were eligible for survival analysis. Results A total of 345 patients with metastatic clear cell histology were analyzed, with a median age of 61 years (range: 20-84 years). One hundred and eighty patients (52%) underwent nephrectomy before systemic therapy. The majority received pazopanib (257 patients, 75%), followed by sunitinib (36 patients, 10%) and cabozantinib (21 patients, 6%); 145 (45%) patients required dose interruption, and 143 (43%) required dose modification of TKI for adverse events. After a median follow-up of 44 months, the median progression-free survival (PFS) was 20.3 months (95% CI: 17.8-24.8), and the median overall survival (OS) was 22.7 months (95% CI: 18.8-28.3). In the poor-risk International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) group, no prior nephrectomy emerged as an independent poor-risk factor for both PFS and OS in multivariate analysis. Conclusion This is the largest single-center cohort of clear cell mRCC from Asia. Median PFS was 20.3 months with predominantly TKI monotherapy. In the poor-risk IMDC group, no prior nephrectomy emerged as an independent poor-risk factor for both PFS and OS.

12.
Front Public Health ; 11: 960500, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37033074

RESUMO

Introduction: Intercity mobility restriction, physical distancing, and mask-wearing are preventive behaviors to reduce the transmission of COVID-19. However, strong cultural and religious traditions become particular challenges in Indonesia. This study uses the Behavior Change Wheel to explore barriers and facilitators for intercity mobility restriction, physical distancing, and mask-wearing during Ramadan. Methods: Semi-structured in-depth interviews with 50 Indonesian adults were conducted between 10 April and 4 June 2020. Having mapped codes into the Capacity, Opportunity, Motivation - Behavior (COM-B), and Theoretical Domain Framework (TDF) model, we conducted summative content analysis to analyze the most identified factors to preventive behaviors and proposed interventions to address those factors. Results: Belief about the consequence of preventive behaviors was the most mentioned facilitator to all preventive behaviors among compliers. However, optimism as a TDF factor was commonly mentioned as a barrier to preventive behaviors among non-compliers, while environmental context and resources were the most commonly mentioned factors for intercity mobility restriction. Conclusions: Public health intervention should be implemented considering the persuasion and involvement of religious and local leaders. Concerning job and economic context, policy related to the intercity mobility restriction should be reconsidered to prevent a counterproductive effect.


Assuntos
COVID-19 , Humanos , COVID-19/prevenção & controle , Indonésia , Saúde Pública , Motivação
13.
Ecancermedicalscience ; 17: 1647, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38414934

RESUMO

Despite the high cancer burden in low-middle-income-countries, medical students often have inadequate exposure to oncology. This may contribute to reduced interest in pursuing training in the field. The second ecancer TMC Oncology Congress at Kolkata on 30th September and 1st October 2023 was planned primarily to introduce undergraduate medical and allied health science students to oncology. There were separate sessions on breast cancer, thyroid cancer, myeloma and research methods so that students get exposure to a wide range of topics. Multi-disciplinary case-based discussions on common clinical presentations helped the students grasp the way a modern cancer hospital functions. Eighty-two percent (131/159, 82%) of the pre-registered delegates attended the congress alongside 44 national and international faculty from surgical oncology, radiation oncology, medical oncology, nuclear medicine, radiology, histopathology, psychiatry and palliative medicine. Of those who offered written anonymous feedback, 76% (70/91, 76%) rated the congress to be excellent. Broadly the following themes emerged from the qualitative feedback a) Delegates positively viewed the opportunity to 'interact and learn from some of the best of minds in the field of medicine' b) Suggestions included 'more interactive sessions through case histories, demonstrations of techniques, videos, quizzes, etc.' to make the learning experience more engaging. c) Considerable appreciation was expressed for learning about 'scientific writing' d) A few delegates were also inspired by the 'style' of some of the presentations and felt that this would help to design their presentations in the future. Introducing oncology early during their career may inspire undergraduate students to explore the option of pursuing a career in oncology and allied specialties. A video summarising the event is available at https://ecancer.org/en/video/11672-introducing-oncology-to-undergraduate-medical-and-allied-health-sciences-students. All the talks presented during the conference are available at https://ecancer.org/en/conference/1505-2nd-ecancer-tmc-kolkata-oncology-congress.

14.
Adv Mater Technol ; 8(6)2023 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-37600966

RESUMO

Adoptive T-cell therapies (ATCTs) are increasingly important for the treatment of cancer, where patient immune cells are engineered to target and eradicate diseased cells. The biomanufacturing of ATCTs involves a series of time-intensive, lab-scale steps, including isolation, activation, genetic modification, and expansion of a patient's T-cells prior to achieving a final product. Innovative modular technologies are needed to produce cell therapies at improved scale and enhanced efficacy. In this work, well-defined, bioinspired soft materials were integrated within flow-based membrane devices for improving the activation and transduction of T cells. Hydrogel coated membranes (HCM) functionalized with cell-activating antibodies were produced as a tunable biomaterial for the activation of primary human T-cells. T-cell activation utilizing HCMs led to highly proliferative T-cells that expressed a memory phenotype. Further, transduction efficiency was improved by several fold over static conditions by using a tangential flow filtration (TFF) flow-cell, commonly used in the production of protein therapeutics, to transduce T-cells under flow. The combination of HCMs and TFF technology led to increased cell activation, proliferation, and transduction compared to current industrial biomanufacturing processes. The combined power of biomaterials with scalable flow-through transduction techniques provides future opportunities for improving the biomanufacturing of ATCTs.

15.
J Biol Chem ; 286(25): 22235-42, 2011 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-21531728

RESUMO

Human factor H (HufH), a key inhibitor of the alternative pathway of complement, binds to Neisseria gonorrhoeae and constitutes an important mechanism of human-specific complement evasion. The C-terminal domain 20 of HufH contains the binding site for sialylated gonococci. We exploited differences in amino acid sequences between human and non-binding chimpanzee fH domain 20 to create cross-species mutations to define amino acids important for binding to sialylated gonococci. We used fH/Fc fusion constructs that contained contiguous fH domains 18-20 fused to Fc fragments of murine IgG2a. The Fc region was used both as a tag for detection of each fusion molecule on the bacterial surface and as an indicator for complement-dependent killing. Arg-1203 was critical for binding to both porin (Por) B.1A and PorB.1B strains. Modeling of the R1203N human-to-chimpanzee mutation using the crystal structure of HufH19-20 as a template showed a loss of positive charge that protrudes at the C terminus of domain 20. We tested the functional importance of Arg-1203 by incubating sialylated gonococci with normal human serum, in the presence of wild-type HufH18-20/Fc or its R1203A mutant. Gonococci bound and were killed by wild-type HufH18-20/Fc but not by the R1203A mutant. A recombinant fH/Fc molecule that contained chimpanzee domain 20, humanized only at amino acid 1203 (N1203R) also bound to sialylated gonococci and restored killing. These findings provide further insights into the species specificity of gonococcal infections and proof-of-concept of a novel therapeutic approach against gonorrhea, a disease rapidly becoming resistant to conventional antibiotics.


Assuntos
Fator H do Complemento/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Neisseria gonorrhoeae/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Arginina , Sítios de Ligação , Fator H do Complemento/química , Fator H do Complemento/genética , Fator H do Complemento/farmacologia , Heparina/farmacologia , Humanos , Fragmentos Fc das Imunoglobulinas/genética , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Mutação , Neisseria gonorrhoeae/efeitos dos fármacos , Pan troglodytes , Ligação Proteica/efeitos dos fármacos , Estrutura Terciária de Proteína , Especificidade da Espécie
16.
IEEE J Transl Eng Health Med ; 10: 1100110, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34956741

RESUMO

Objective: Since its outbreak, the rapid spread of COrona VIrus Disease 2019 (COVID-19) across the globe has pushed the health care system in many countries to the verge of collapse. Therefore, it is imperative to correctly identify COVID-19 positive patients and isolate them as soon as possible to contain the spread of the disease and reduce the ongoing burden on the healthcare system. The primary COVID-19 screening test, RT-PCR although accurate and reliable, has a long turn-around time. In the recent past, several researchers have demonstrated the use of Deep Learning (DL) methods on chest radiography (such as X-ray and CT) for COVID-19 detection. However, existing CNN based DL methods fail to capture the global context due to their inherent image-specific inductive bias. Methods: Motivated by this, in this work, we propose the use of vision transformers (instead of convolutional networks) for COVID-19 screening using the X-ray and CT images. We employ a multi-stage transfer learning technique to address the issue of data scarcity. Furthermore, we show that the features learned by our transformer networks are explainable. Results: We demonstrate that our method not only quantitatively outperforms the recent benchmarks but also focuses on meaningful regions in the images for detection (as confirmed by Radiologists), aiding not only in accurate diagnosis of COVID-19 but also in localization of the infected area. The code for our implementation can be found here - https://github.com/arnabkmondal/xViTCOS. Conclusion: The proposed method will help in timely identification of COVID-19 and efficient utilization of limited resources.


Assuntos
COVID-19 , Aprendizado Profundo , COVID-19/diagnóstico por imagem , Humanos , Radiografia Torácica , SARS-CoV-2 , Raios X
17.
Indian J Hematol Blood Transfus ; 38(1): 31-41, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35125710

RESUMO

BACKGROUND: Cytarabine based therapy has been the standard consolidation regimen for AML (acute myeloid leukemia) for decades. However, the optimal dose, regimen and schedule is not known. HIDAC (high dose cytarabine at 18 g/m2) has been the conventional standard, however, recent studies have shown that intermediate doses of cytarabine (IDAC) have equal efficacy and lesser toxicities. METHODS: We retrospectively analysed 75 AML patients who entered consolidation out of 167 patients who underwent induction therapy between 2014 and 2018. HIDAC (at 18 g/m2) was given to 39 patients and 36 patients received IDAC at 9 g/m2. RESULTS: Median age was 28 years (range 2-60). Male: female ratio was 1.02. More courses were administered in out-patient setting in IDAC group 61% (n = 58/95 courses) than in HIDAC 29% (n = 29/101 courses); p < 0.001. Incidence of clinically documented infection (CDI) was higher in HIDAC group (23.7%) compared to IDAC (8.4%), p = 0.004, and diarrhea showed a higher trend in the HIDAC group (9.9% vs. 3.1%; p = 0.052). Other toxicities were similar in both groups. There were 4 consolidation deaths in HIDAC whereas 3 deaths in IDAC group (p = 0.775). Median OS was 19.7 vs. 16.2 months and 3 years OS was 49.1% vs. 34.7% in HIDAC and IDAC groups respectively (p = 0.570). Median LFS was 12.6 versus 11.8 months; 3 years LFS was 46.4% versus 31% in HIDAC and IDAC groups respectively (p = 0.278). CONCLUSION: For AML consolidation IDAC had lesser toxicity when compared with HIDAC though comparable efficacy needs to be confirmed with longer follow up and with prospective studies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12288-021-01430-z.

18.
Biomater Sci ; 10(19): 5689-5706, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36018297

RESUMO

The pulmonary fibrotic microenvironment is characterized by increased stiffness of lung tissue and enhanced secretion of profibrotic soluble cues contributing to a feedback loop that leads to dysregulated wound healing and lung failure. Pinpointing the individual and tandem effects of profibrotic stimuli in impairing immune cell response remains difficult and is needed for improved therapeutic strategies. We utilized a statistical design of experiment (DOE) to investigate how microenvironment stiffness and interleukin 13 (IL13), a profibrotic soluble factor linked with disease severity, contribute to the impaired macrophage response commonly observed in pulmonary fibrosis. We used engineered bioinspired hydrogels of different stiffness, ranging from healthy to fibrotic lung tissue, and cultured murine alveolar macrophages (MH-S cells) with or without IL13 to quantify cell response and analyze independent and synergistic effects. We found that, while both stiffness and IL13 independently influence macrophage morphology, phenotype, phagocytosis and efferocytosis, these factors work synergistically to exacerbate impaired macrophage phenotype and efferocytosis. These unique findings provide insights into how macrophages in fibrotic conditions are not as effective in clearing debris, contributing to fibrosis initiation/progression, and more broadly inform how underlying drivers of fibrosis modulate immune cell response to facilitate therapeutic strategies.


Assuntos
Macrófagos Alveolares , Fibrose Pulmonar , Animais , Fibrose , Hidrogéis/uso terapêutico , Interleucina-13/uso terapêutico , Macrófagos Alveolares/patologia , Camundongos , Fenótipo , Fibrose Pulmonar/induzido quimicamente
19.
Med Res Arch ; 10(10)2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36382204

RESUMO

Neurological manifestations of scrub typhus, a re-emerging infectious disease of tropic/subtropics caused by Orientia tsutsugamushi infection, have been ever-evolving. Several central nervous system infections have been acknowledged for the development of cerebral venous sinus thrombosis (CVT). Nevertheless, CVT has been a rarely described addendum to the ever-evolving "neuro-scrub" spectrum. Proposed pathogenesis for the development of CVT is disseminated endotheliitis resulting in the triad of venous stasis (due to raised intracranial pressure), cerebral vasculopathy (endothelial damage), and capillary perivasculitis (endothelial damage and resultant hypercoagulable state generated by inflammatory mediators). We herein report a case of a previously healthy young female from the Indian subcontinent who was diagnosed with CVT, following scrub typhus. She responded well to conventional therapy with antibiotics and anticoagulants. CVT is amid the few completely reversible neurological catastrophes if diagnosed and treated early. Again, scrub typhus infection is treated with commonly available and extremely "affordable" antibiotics therapy. Hence, the authors propose that all cases of acute febrile illness with neurological manifestations from scrub-typhus endemic zones (like several parts of India) should be tested for the presence of Orientia tsutsugamushi infection and treated accordingly.

20.
Biosci Rep ; 41(8)2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34308969

RESUMO

Misfolded, pathological tau protein propagates from cell to cell causing neuronal degeneration in Alzheimer's disease and other tauopathies. The molecular mechanisms of this process have remained elusive. Unconventional secretion of tau takes place via several different routes, including direct penetration through the plasma membrane. Here, we show that tau secretion requires membrane interaction via disulphide bridge formation. Mutating residues that reduce tau interaction with membranes or formation of disulphide bridges decrease both tau secretion from cells, and penetration through artificial lipid membranes. Our results demonstrate that tau is indeed able to penetrate protein-free membranes in a process independent of active cellular processes and that both membrane interaction and disulphide bridge formation are needed for this process. QUARK-based de novo modelling of the second and third microtubule-binding repeat domains (MTBDs), in which the two cysteine residues of 4R isoforms of tau are located, supports the concept that this region of tau could form transient amphipathic helices for membrane interaction.


Assuntos
Membrana Celular/metabolismo , Dissulfetos/metabolismo , Neurônios/metabolismo , Proteínas tau/metabolismo , Animais , Linhagem Celular Tumoral , Cisteína , Dissulfetos/química , Humanos , Camundongos , Modelos Moleculares , Mutação , Conformação Proteica em alfa-Hélice , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Via Secretória , Relação Estrutura-Atividade , Proteínas tau/química , Proteínas tau/genética
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