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Purpose Abnormal liver blood tests (ALBTs), neutropenia (NEU) and thymic hyperplasia (TH) are new features of Graves' disease (GD). Our objectives were: (a) to calculate the accuracy of TH in discriminating between Graves’ and non-Graves’ thyrotoxicosis, compared to ALBTs, NEU and Graves’ orbitopathy (GO); (b) to explore the outcome of GD-associated TH and non-GD-associated TH. Methods We prospectively analyzed consecutive adult patients with newly diagnosed thyrotoxicosis from January 2018 to June 2023. TH was detected via neck ultrasound (nUS) then confirmed and followed by magnetic resonance imaging (MRI). For GD vs non-GD clinical sensitivity (SE) and specificity (SPEC), accuracy, positive predictive value (PPV) and negative predictive value (NPV) of GO, TH, ALBTs and NEU were calculated. Results 264 thyrotoxic patients were included. TH was found in 16.4% (20/122) of GD vs 1.4% (2/142) in non-GD ( p  < 0.001). SE, SPEC, accuracy, PPV and NPV of the four extrathyroidal manifestations of GD were as follows, respectively: GO 26%, 100%, 66%, 100%, 61%; ALBTs 41%, 89%, 69%, 76%, 66%; NEU 5%, 100%, 56%, 100%, 55%; TH 16%, 98%, 61%, 91%, 98%. In 18 of them, TH regressed within 12 months after achieving euthyroidism under anti-thyroid drug therapy, while in the remaining 2, TH regressed 6 months after thyroid surgery. In the two non-GD patients with TH, thymus disappeared along with euthyroidism. Conclusions TH in the hyperthyroidism scenario provides a high PPV for GD. A conservative approach for the diagnostic work‐up and initial management of thyrotoxicosis-associated TH should be adopted.

The growth factor receptor-bound protein 2 (Grb2) is a key factor in the regulation of cell survival, proliferation, differentiation, and metabolism. In its structure, the central Src homology 2 (SH2) domain is flanked by two Src homology 3 (SH3). SH2 is the most important domain in the recognition of phosphotyrosines. Here, we present the first dynamical characterization of Grb2-SH2 domain in the free state and in the presence of phosphopeptide EpYINSQV at multiple timescales, which revealed valuable information to the understanding of phophotyrosine sensing mechanism. Grb2-SH2 presented two dynamically independent subdomains, subdomain I involved in pY recognition and subdomain II is the pY + 2 specificity pocket. Under semi-saturated concentrations of pY-pep we observed fuzzy interactions, which led to chemical exchange observed by NMR. This information was used to describe the encounter complex. The association with pY-pep is dynamic, involving fuzzy interactions and multiple conformations of pY-pep with negative and hydrophobic residues, creating an electrostatic-potential that drives the binding of pY-pep. The recognition face is wider than the binding site, with many residues beyond the central SH2 binding site participating in the association complex, which contribute to explain previously reported capability of Grb2 to recognize remote pY.

Background Glioblastoma (GBM), the most common primary malignant brain tumor in adults, remains uniformly fatal due to the lack of effective targeted therapies. The epidermal growth factor receptor (EGFR) is the most frequently altered receptor tyrosine kinase oncogene in GBM with most alterations impacting the receptor ectodomain function, including gene amplification, mutation, rearrangement, and splicing site changes, which occur in approximately 50% of GBM tumors. Depatuxizumab mafodotin (Depatux-M; ABT-414), an antibody-drug conjugate composed of an EGFR-specific antibody (ABT-806) that recognizes the EGFR ectodomain linked to the cytotoxic agent monomethyl auristatin F, initially showed clinical promise. However, it failed to improve survival in phase III trials, highlighting an urgent need to understand mechanisms of resistance. Methods We generated in vivo ABT-414 resistant GBM models using patient-derived xenografts (PDXs) and performed genomics and transcriptomic profiling, including whole exome sequencing, bulk RNA sequencing, and single-cell RNA sequencing. Results ABT-414-resistant tumors exhibited transcriptional reprogramming characterized by upregulation of synaptic and developmental gene networks and downregulation of biosynthetic processes, indicative of a plastic, therapy-adaptive state. Whole-exome sequencing revealed novel mutations exclusive to resistant tumors, including a recurrent TEK (TIE2) S466I point mutation present in all ABT-414 resistant GBM12 PDX tumors. Functional validation demonstrated that ectopic expression of TEK S466I and TEK WT in PDX models reduced EGFR levels, suggesting a novel feedback mechanism linking TEK signaling to EGFR downregulation and contributes to resistance. Conclusion Our findings demonstrate that resistance to ABT-414 arises through both adaptive transcriptional remodeling and newly acquired genetic alterations. TEK-mediated suppression of EGFR represents a previously unrecognized mechanism of resistance, with potential implications for overcoming antibody-drug conjugate failure in GBM.

HSP70 chaperones play pivotal roles in facilitating protein folding, refolding, and disaggregation through their binding and releasing activities. This intricate process is further supported by J-domain proteins (JDPs), also known as DNAJs or HSP40s, which can be categorized into classes A and B. In yeast, these classes are represented by Ydj1 and Sis1, respectively. While both classes stimulate the ATPase activity of Ssa1 (yeast HSP70) through the J-domain, only class B JDPs possess the unique ability to efficiently stimulate Ssa1 in disaggregation processes. The C-terminal EEVD motif of HSP70 plays a crucial role in mediating these interactions by connecting with both client proteins and JDPs. However, the removal of the EEVD motif disrupts the capacity of HSP70 to associate with class B JDPs, and the intricacies of the interaction between these two proteins remain incompletely understood. We employed NMR spectroscopy to investigate the structure and dynamics of the class B J domain protein (JDP) of S. cerevisiae (Sis1) complexed with an EEVD peptide of Ssa1. Our study is based on the extraordinary 70.5% residue assignment of the full-length (352 residues long) Sis1. Our findings revealed that EEVD binds to two distinct sites within the C-terminal domain I (CTDI) of Sis1, to the J domain and to the GF-rich loop located between the J domain and α-helix 6 (a structure identified by this work). We propose that the interaction between EEVD and Sis1 facilitates the dissociation of α-helix 6, promoting a conformational state that is more favorable for interaction with Ssa1. We also employed α-synuclein as a substrate to investigate the competitive nature between EEVD and the client protein. Our experimental findings provide evidence supporting the interaction of EEVD with the client protein at multiple sites and essential insights into the mechanistic cycle of class B JDPs.

We synthesised and screened 18 aromatic derivatives of guanylhydrazones and oximes aromatic for their capacity to bind to dengue virus capsid protein (DENVC). The intended therapeutic target was the hydrophobic cleft of DENVC, which is a region responsible for its anchoring in lipid droplets in the infected cells. The inhibition of this process completely suppresses virus infectivity. Using NMR, we describe five compounds able to bind to the α1-α2 interface in the hydrophobic cleft. Saturation transfer difference experiments showed that the aromatic protons of the ligands are important for the interaction with DENVC. Fluorescence binding isotherms indicated that the selected compounds bind at micromolar affinities, possibly leading to binding-induced conformational changes. NMR-derived docking calculations of ligands showed that they position similarly in the hydrophobic cleft. Cytotoxicity experiments and calculations of in silico drug properties suggest that these compounds may be promising candidates in the search for antivirals targeting DENVC.

A polyelectrolyte (PE) chain in the vicinity of an oppositely charged surface can exhibit a discontinuous transition from the adsorbed to the desorbed state once the electrostatic attractive interactions are not strong enough to overcome the entropic losses caused by the PE-surface adsorption. In the context of PE–protein interactions, the heterogeneity of the charge distribution and the effects of a low dielectric permittivity underneath the surface are crucial. Studies of the combined effects of these two properties are very sparse, especially in the spherical geometry; we thus fill this gap here. We study the adsorption of PE chains onto spherical particles with heterogeneously charged surfaces, with the main focus on the critical-adsorption conditions and the effects of a low-dielectric core. Metropolis Monte Carlo simulations are employed, with the PE exploring the phase-space around the binding particle in the canonical ensemble. Two adsorption–desorption transitions are observed when the particle possesses a net charge of the same sign as that of the PE, resulting in nonmonotonic behavior of the critical charge density required for the PE–particle electrostatically driven adsorption. An increased affinity between the PEs and low-dielectric particles with variable heterogeneous charge distributions is observed, in contrast to the behavior detected for homogeneous low-dielectric particles. This higher affinity occurs when the Debye screening length in the solution becomes comparable to the dimensions of a patch of the opposite sign to the PE. A number of real-life applications of the considered PE–particle system is presented in the discussion, in particular regarding the properties of the complex formation between various PEs and globular proteins featuring a dipolar-type distribution of electric charges on their surfaces, such as insulin and bovine serum albumin.

The human Respiratory Syncytial Virus (hRSV) is the most frequent agent of respiratory infections in infants and children with no currently approved vaccine. The M2-1 protein is an important transcriptional antitermination factor and a potential target for viral replication inhibitor development. Hesperetin (HST) and hesperidin (HSD) are flavonoids from the flavanone group, naturally found in citrus and have, as one of their properties, antiviral activity. The present study reports on the interactions between hRSV M2-1 and these flavanones using experimental techniques in association with computational tools. STD-NMR results showed that HST and HSD bind to M2-1 by positioning their aromatic rings into the target protein binding site. Fluorescence quenching measurements revealed that HST had an interaction affinity greater than HSD towards M2-1. The thermodynamic analysis suggested that hydrogen bonds and van der Waals interactions are important for the molecular stabilization of the complexes. Computational simulations corroborated with the experimental results and indicated that the possible interaction region for the flavonoids is the AMP-binding site in M2-1. Therefore, these results point that HST and HSD bind stably to a critical region in M2-1, which is vital for its biological function, and thus might play a possible role antiviral against hRSV.

Background We developed an integrated multi-omics analysis in metastatic melanoma (MM) cohorts to associate DNA methylation profiles with tumor progression, survival, response to adjuvant immunotherapy, structure of the tumor immune microenvironment and transcriptional programs of immunity and melanoma differentiation. Methods Lesions ( n  = 191) from a fully annotated, retrospective cohort of 165 AJCC 8th Stage III and IV melanoma patients (EPICA cohort) were characterized by reduced representation bisulfite sequencing, RNA sequencing, whole exome sequencing, quantitative immunohistochemistry and multiplex immunofluorescence analysis. The TCGA melanoma datasets were used for validation. Pre-therapy lesions ( n  = 28) from a cohort of MM patients treated with adjuvant immune checkpoint blockade were characterized for the DNA methylation profile. Impact of a DNMT inhibitor on DNA methylation and transcriptomic profiles of melanoma cell lines was investigated by EPIC arrays and Clariom S arrays. Results Four tumor subsets (i.e. DEMethylated, LOW, INTermediate and CIMP) with progressively increasing levels of DNA methylation were identified in EPICA, TCGA MM and TCGA primary melanoma cohorts. EPICA patients with LOW methylation tumors exhibited a significantly longer survival and a lower progression rate to more advanced AJCC stages, compared to patients with CIMP tumors. In an adjuvant immune checkpoint blockade cohort, patients with DEM/LOW pre-therapy lesions showed significantly longer relapse-free survival compared to those with INT/CIMP lesions. RNA-seq data analysis revealed that LOW and CIMP EPICA tumors showed opposite activation of master molecules influencing prognostic target genes, and differential expression of immunotherapy response and melanoma differentiation signatures. Compared to CIMP tumors, LOW lesions showed enrichment for CD8 + TCF-1 + PD-1 + TIM-3 − pre-exhausted and CD8 + TCF-1 − PD-1 + TIM-3 + exhausted T cells, more frequent retention of HLA Class I antigens and a de-differentiated melanoma phenotype. The differentiation and immune-related transcriptional features associated with LOW vs CIMP lesions were tumor-intrinsic programs retained in-vitro by melanoma cell lines. Consistently, treatment of differentiated melanoma cell lines with a DNMT inhibitor induced global DNA de-methylation, promoted de-differentiation and upregulated viral mimicry and IFNG predictive signatures of immunotherapy response. Conclusions These results reveal the biological, prognostic and therapeutic relevance of DNA methylation classes in MM and support methylome targeting strategies for precision immunotherapy.