Publications by authors named "Helder V Ribeiro Filho"

Article Synopsis
  • - T cell receptors (TCRs) that target cancer neoantigens play a crucial role in triggering immune responses and improving cancer immunotherapy, and understanding their structure can lead to better TCR designs.
  • - Researchers determined the crystal structures of a specific TCR with two NRAS neoantigen peptides and MHC, uncovering how TCRs can specifically recognize different versions of the same peptide.
  • - The study also utilized AlphaFold to model these TCR-peptide-MHC complexes, demonstrating the effectiveness of this tool in predicting immunological interactions despite some challenges with accuracy in certain cases.
View Article and Find Full Text PDF

Deep learning methods, trained on the increasing set of available protein 3D structures and sequences, have substantially impacted the protein modeling and design field. These advancements have facilitated the creation of novel proteins, or the optimization of existing ones designed for specific functions, such as binding a target protein. Despite the demonstrated potential of such approaches in designing general protein binders, their application in designing immunotherapeutics remains relatively underexplored.

View Article and Find Full Text PDF

T cell receptors (TCRs) that recognize cancer neoantigens are important for anti-cancer immune responses and immunotherapy. Understanding the structural basis of TCR recognition of neoantigens provides insights into their exquisite specificity and can enable design of optimized TCRs. We determined crystal structures of a human TCR in complex with NRAS Q61K and Q61R neoantigen peptides and HLA-A1 MHC, revealing the molecular underpinnings for dual recognition and specificity versus wild-type NRAS peptide.

View Article and Find Full Text PDF

The ability to control protein conformations and dynamics through structure-based design has been useful in various scenarios, including engineering of viral antigens for vaccines. One effective design strategy is the substitution of residues to proline amino acids, which due to its unique cyclic side chain can favor and rigidify key backbone conformations. To provide the community with a means to readily identify and explore proline designs for target proteins of interest, we developed the Proscan web server.

View Article and Find Full Text PDF

Deep learning methods, trained on the increasing set of available protein 3D structures and sequences, have substantially impacted the protein modeling and design field. These advancements have facilitated the creation of novel proteins, or the optimization of existing ones designed for specific functions, such as binding a target protein. Despite the demonstrated potential of such approaches in designing general protein binders, their application in designing immunotherapeutics remains relatively unexplored.

View Article and Find Full Text PDF

Molecular interactions that modulate catalytic processes occur mainly in cavities throughout the molecular surface. Such interactions occur with specific small molecules due to geometric and physicochemical complementarity with the receptor. In this scenario, we present KVFinder-web, an open-source web-based application of parKVFinder software for cavity detection and characterization of biomolecular structures.

View Article and Find Full Text PDF

The cellular immune system, which is a critical component of human immunity, uses T cell receptors (TCRs) to recognize antigenic proteins in the form of peptides presented by major histocompatibility complex (MHC) proteins. Accurate definition of the structural basis of TCRs and their engagement of peptide-MHCs can provide major insights into normal and aberrant immunity, and can help guide the design of vaccines and immunotherapeutics. Given the limited amount of experimentally determined TCR-peptide-MHC structures and the vast amount of TCRs within each individual as well as antigenic targets, accurate computational modeling approaches are needed.

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on how the Mayaro virus (MAYV) adapts to urban mosquito vectors like Ae. aegypti, which could influence its transmission and emergence as a health threat.
  • Researchers discovered a specific mutation (E2-T179N) that enhances MAYV replication in mosquitoes, improving its transmission after passing through the mosquito's gut, but it reduces its ability to replicate in human cells.
  • The findings suggest that while this mutation may increase the virus's ability to spread through mosquitoes, it compromises its efficiency in human hosts, indicating a complex trade-off in virus adaptation that might lead to future emergence of outbreaks.
View Article and Find Full Text PDF

The Hippo pathway plays central roles in relaying mechanical signals during development and tumorigenesis, but how the proteostasis of the Hippo kinase MST2 is regulated remains unknown. Here, we found that chemical inhibition of proteasomal proteolysis resulted in increased levels of MST2 in human breast epithelial cells. MST2 binds SCF E3 ubiquitin ligase and silencing βTrCP resulted in MST2 accumulation.

View Article and Find Full Text PDF

The nucleocapsid (N) protein of the SARS-CoV-2 virus, the causal agent of COVID-19, is a multifunction phosphoprotein that plays critical roles in the virus life cycle, including transcription and packaging of the viral RNA. To play such diverse roles, the N protein has two globular RNA-binding modules, the N- (NTD) and C-terminal (CTD) domains, which are connected by an intrinsically disordered region. Despite the wealth of structural data available for the isolated NTD and CTD, how these domains are arranged in the full-length protein and how the oligomerization of N influences its RNA-binding activity remains largely unclear.

View Article and Find Full Text PDF

Chronic pain is a major health issue, and the search for new analgesics has become increasingly important because of the addictive properties and unwanted side effects of opioids. To explore potentially new drug targets, we investigated mutations in the gene found in individuals with congenital insensitivity to pain with anhidrosis (CIPA). encodes tropomyosin receptor kinase A (TrkA), the receptor for nerve growth factor (NGF) and that contributes to nociception.

View Article and Find Full Text PDF

Background: Biomolecular interactions that modulate biological processes occur mainly in cavities throughout the surface of biomolecular structures. In the data science era, structural biology has benefited from the increasing availability of biostructural data due to advances in structural determination and computational methods. In this scenario, data-intensive cavity analysis demands efficient scripting routines built on easily manipulated data structures.

View Article and Find Full Text PDF

Mayaro virus (MAYV) is an emerging arbovirus of the Americas that may cause a debilitating arthritogenic disease. The biology of MAYV is not fully understood and largely inferred from related arthritogenic alphaviruses. Here, we present the structure of MAYV at 4.

View Article and Find Full Text PDF

The present investigation aimed to characterize the effect of a short-time treatment with a new thiazolidinedione (TZD) derivative, GQ-130, on metabolic alterations in rats fed a high-fat diet (HFD). We investigated whether metabolic alterations induced by GQ-130 were mediated though a mechanism that involves PPARβ/δ transactivation. Potential binding and transactivation of PPARα, PPARβ/δ or PPARγ by GQ-130 were examined through cell transactivation, 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence quenching assays and thermal shift assay.

View Article and Find Full Text PDF

A group of nitro compounds contains a benzene ring in a short aliphatic chain with the NO group, property that supposedly favors its vasodilator profile. In this study, we evaluated in isolated rat aorta the effects of 1-nitro-2-propylbenzene (NPB), a nitro compound containing the NO in the aromatic ring. In aorta precontracted with KCl, NPB (1-3000 μm) induced full endothelium-independent relaxation.

View Article and Find Full Text PDF

Purpose: Anticancer-drug efficacy seems to involve the direct interaction with host immune cells. Although topoisomerase I (Top I) inhibitors have been suggested to block LPS-evoked inflammation, the interaction between these drugs and toll-like receptor 4 (TLR4) is unaddressed.

Methods: SN-38, the active metabolite of the Top I inhibitor irinotecan, and TLR4 interaction was assessed using the in vitro luciferase nuclear factor-κB reporter assay, neutrophil migration to murine air-pouch, in silico simulation, and the thermal shift assay (TSA).

View Article and Find Full Text PDF

Thyroid hormone receptors (TRs) are responsible for mediating thyroid hormone (T3 and T4) actions at a cellular level. They belong to the nuclear receptor (NR) superfamily and execute their main functions inside the cell nuclei as hormone-regulated transcription factors. These receptors also exhibit so-called "non-classic" actions, for which other cellular proteins, apart from coregulators inside nuclei, regulate their activity.

View Article and Find Full Text PDF

Undergraduate biomedical students often have difficulties in understanding basic concepts of respiratory physiology, particularly respiratory mechanics. In this study, we report the use of electrical impedance tomography (EIT) to improve and consolidate the knowledge about physiological aspects of normal regional distribution of ventilation in humans. Initially, we assessed the previous knowledge of a group of medical students ( n = 39) about regional differences in lung ventilation.

View Article and Find Full Text PDF

Compounds containing a nitro group may reveal vasodilator properties. Several nitro compounds have a NO group in a short aliphatic chain connected to an aromatic group. In this study, we evaluated in rat aorta the effects of two nitro compounds, with emphasis on a putative recruitment of the soluble guanylate cyclase (sGC) pathway to induce vasodilation.

View Article and Find Full Text PDF

Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of a nuclear receptor superfamily and acts as a ligand-dependent transcription factor, playing key roles in maintenance of adipose tissue and in regulation of glucose and lipid homeostasis. This receptor is the target of thiazolidinediones, a class of antidiabetic drugs, which improve insulin sensitization and regulate glycemia in type 2 diabetes. Despite the beneficial effects of drugs, such as rosiglitazone and pioglitazone, their use is associated with several side effects, including weight gain, heart failure, and liver disease, since these drugs induce full activation of the receptor.

View Article and Find Full Text PDF

β-Citronellol is a monoterpene found in the essential oil of various plants with antihypertensive properties. In fact, β-citronellol possesses hypotensive actions due to its vasodilator abilities. Here we aimed to show that β-citronellol recruits airway sensory neural circuitry to evoke cardiorespiratory effects.

View Article and Find Full Text PDF

Methyl cinnamate (MC) is a safe flavoring agent useful to food industry. Although chemically analog to tyrosine kinase inhibitors, there is little information regarding its biological actions. Here, we aimed at assessing the MC effects on gastrointestinal contractility and the putative involvement of tyrosine kinase in the mediation of these effects.

View Article and Find Full Text PDF