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Arctic (E22G) mutation in amyloid-β (Aβ enhances Aβ40 fibril accumulation in Alzheimer's disease (AD). Unlike sporadic AD, familial AD (FAD) patients with the mutation exhibit more Aβ40 in the plaque core. However, structural details of E22G Aβ40 fibrils remain elusive, hindering therapeutic progress. Here, we determine a distinctive W-shaped parallel β-sheet structure through co-analysis by cryo-electron microscopy (cryoEM) and solid-state nuclear magnetic resonance (SSNMR) of in-vitro-prepared E22G Aβ40 fibrils. The E22G Aβ40 fibrils displays typical amyloid features in cotton-wool plaques in the FAD, such as low thioflavin-T fluorescence and a less compact unbundled morphology. Furthermore, kinetic and MD studies reveal previously unidentified in-vitro evidence that E22G Aβ40, rather than Aβ42, may trigger Aβ misfolding in the FAD, and prompt subsequent misfolding of wild-type (WT) Aβ40/Aβ42 via cross-seeding. The results provide insight into how the Arctic mutation promotes AD via Aβ40 accumulation and cross-propagation. Here, the authors use cryo-electron microscopy and solid-state NMR in concert to determine a distinctive W-shaped parallel β-sheet structure of in-vitro-prepared E22G Aβ40 fibrils. [ABSTRACT FROM AUTHOR]

The intraflagellar transport (IFT) machinery plays a crucial role in the bidirectional trafficking of components necessary for ciliary signaling, such as the Hedgehog, Wnt/PCR, and cAMP/PKA systems. Defects in some components of the IFT machinery cause dysfunction, leading to a wide range of human diseases and developmental disorders termed ciliopathies, such as nephronophthisis. The IFT machinery comprises three sub-complexes: BBsome, IFT-A, and IFT-B. The IFT protein 54 (IFT54) is an important component of the IFT-B sub-complex. In anterograde movement, IFT54 binds to active kinesin-II, walking along the cilia microtubule axoneme and carrying the dynein-2 complex in an inactive state, which works for retrograde movement. Several mutations in IFT54 are known to cause Senior-Loken syndrome, a ciliopathy. IFT54 possesses a divergent Calponin Homology (CH) domain termed as NN-CH domain at its N-terminus. However, several aspects of the function of the NN-CH domain of IFT54 are still obscure. Here, we report the 1H, 15N, and 13C resonance assignments of the NN-CH domain of human IFT54 and its solution structure. The NN-CH domain of human IFT54 adopts essentially the α1–α2–α3–α4–α5 topology as that of mouse IFT54, whose structure was determined by X-ray crystallographic study. The structural information and assignments obtained in this study shed light on the molecular function of the NN-CH domain in IFT54. [ABSTRACT FROM AUTHOR]

More than one percent of people have epilepsy worldwide. Levetiracetam (LEV) is a successful new-generation antiepileptic drug (AED), and its derivative, brivaracetam (BRV), shows improved efficacy. Synaptic vesicle glycoprotein 2a (SV2A), a putative membrane transporter in the synaptic vesicles (SVs), has been identified as a target of LEV and BRV. SV2A also serves as a receptor for botulinum neurotoxin (BoNT), which is the most toxic protein and has paradoxically emerged as a potent reagent for therapeutic and cosmetic applications. Nevertheless, no structural analysis on AEDs and BoNT recognition by full-length SV2A has been available. Here we describe the cryo-electron microscopy structures of the full-length SV2A in complex with the BoNT receptor-binding domain, BoNT/A2 HC, and either LEV or BRV. The large fourth luminal domain of SV2A binds to BoNT/A2 HC through protein-protein and protein-glycan interactions. LEV and BRV occupy the putative substrate-binding site in an outward-open conformation. A propyl group in BRV creates additional contacts with SV2A, explaining its higher binding affinity than that of LEV, which was further supported by label-free spectral shift assay. Numerous LEV derivatives have been developed as AEDs and positron emission tomography (PET) tracers for neuroimaging. Our work provides a structural framework for AEDs and BoNT recognition of SV2A and a blueprint for the rational design of additional AEDs and PET tracers. SV2A is a receptor for botulinum neurotoxin (BoNT) and new generation antiepileptic drugs (AEDs). Here the authors report cryo-EM structures of SV2A in complex with BoNT receptor binding domain and AEDs highlighting the difference in the binding affinity between AEDs. [ABSTRACT FROM AUTHOR]

The tumor microenvironment (TME) consists of cancer cells surrounded by stromal components including tumor vessels. Transforming growth factor‐β (TGF‐β) promotes tumor progression by inducing epithelial–mesenchymal transition (EMT) in cancer cells and stimulating tumor angiogenesis in the tumor stroma. We previously developed an Fc chimeric TGF‐β receptor containing both TGF‐β type I (TβRI) and type II (TβRII) receptors (TβRI‐TβRII‐Fc), which trapped all TGF‐β isoforms and suppressed tumor growth. However, the precise mechanisms underlying this action have not yet been elucidated. In the present study, we showed that the recombinant TβRI‐TβRII‐Fc protein effectively suppressed in vitro EMT of oral cancer cells and in vivo tumor growth in a human oral cancer cell xenograft mouse model. Tumor cell proliferation and angiogenesis were suppressed in tumors treated with TβRI‐TβRII‐Fc. Molecular profiling of human cancer cells and mouse stroma revealed that K‐Ras signaling and angiogenesis were suppressed. Administration of TβRI‐TβRII‐Fc protein decreased the expression of heparin‐binding epidermal growth factor‐like growth factor (HB‐EGF), interleukin‐1β (IL‐1β) and epiregulin (EREG) in the TME of oral cancer tumor xenografts. HB‐EGF increased proliferation of human oral cancer cells and mouse endothelial cells by activating ERK1/2 phosphorylation. HB‐EGF also promoted oral cancer cell‐derived tumor formation by enhancing cancer cell proliferation and tumor angiogenesis. In addition, increased expressions of IL‐1β and EREG in oral cancer cells significantly enhanced tumor formation. These results suggest that TGF‐β signaling in the TME controls cancer cell proliferation and angiogenesis by activating HB‐EGF/IL‐1β/EREG pathways and that TβRI‐TβRII‐Fc protein is a promising tool for targeting the TME networks. [ABSTRACT FROM AUTHOR]

Background: The discovery of glioblastoma (GBM)-initiating cells (GICs) has impacted GBM research. These cells are not only tumorigenic, but also exhibit resistance to radiotherapy and chemotherapy. Therefore, it is crucial to characterize GICs thoroughly and identify new therapeutic targets. In a previous study, we successfully identified Epithelial V-like antigen 1 (EVA1) as a novel functional factor specific to GICs., Methods: Hybridoma cells were generated by immunizing BALB/c mice with EVA1-Fc fusion protein. The reactivity of the supernatant from these hybridoma cells was examined using EVA1-overexpressing cells and GICs. Candidate antibodies were further selected using Biacore surface plasmon resonance analysis and two cytotoxicity assays, antibody-dependent cell cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Among the antibodies, the cytotoxicity of the B2E5-antibody drug conjugate (B2E5-ADC) was evaluated by both adding it to cultured GICs and injecting it into GIC tumor-bearing brains., Results: B2E5 demonstrated a high affinity for human EVA1 and effectively killed both EVA1-expressing cell lines and GICs in culture through ADCC and CDC. B2E5-ADC also exhibited strong cytotoxicity to GICs in culture and prevented their tumorigenesis in the brain when administered intracranially to the tumor-bearing brain., Conclusion: Our data indicate that B2E5-ADC is a new and promising therapeutic strategy for GBM., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Numerous antibody biomarkers have been reported for cancer and atherosclerosis-related diseases. The major complications of atherosclerosis and diabetes mellitus (DM) are acute ischemic stroke (AIS), cardiovascular disease (CVD) and chronic kidney disease (CKD). Cancer development is accompanied by arterial disorders, such as angiogenesis and atherosclerosis, and DM is a risk factor for the development of certain types of cancer. Atherosclerosis-related diseases and cancers are therefore interrelated and could be detected using a common biomarker. In the present study, the initial screening using the protein array method identified KIAA0513 as an antigen recognized by serum IgG antibodies in patients with atherosclerosis. The amplified luminescent proximity homogeneous assay-linked immunosorbent assay revealed significantly higher serum antibody levels against recombinant KIAA0513 protein in patients with AIS, transient ischemic attack (TIA), DM, CVD, obstructive sleep apnea syndrome (OSAS), CKD and solid cancers, such as esophageal, gastric, colon, lung and breast cancers, compared with healthy donors. A receiver operating characteristic (ROC) analysis revealed that the highest areas under the ROC curves of anti-KIAA0513 antibodies were obtained for esophageal cancer, nephrosclerosis-type CKD and DM. Spearman's correlation analysis revealed that serum anti-KIAA0513 antibody levels were associated with maximum intima-media thickness and plaque score, which are indices of atherosclerosis and stenosis. Serum anti-KIAA0513 antibody markers appear to be useful for diagnosing AIS, TIA, DM, CVD, OSAS, CKD and solid cancers, and may reflect common arterial alterations leading to atherosclerotic and cancerous diseases., Competing Interests: The present study was performed in collaboration with Fujikura Kasei Co., Ltd. GT is an employee of Fujikura Kasei Co., Ltd. The other authors have no competing interests., (Copyright: © 2024 Hiwasa et al.)

Brigatinib-based therapy was effective against osimertinib-resistant EGFR C797S mutants and is undergoing clinical studies. However, tumor relapse suggests additional resistance mutations might emerge. Here, we first demonstrated the binding mode of brigatinib to the EGFR-T790M/C797S mutant by crystal structure analysis and predicted brigatinib-resistant mutations through a cell-based assay including N-ethyl-N-nitrosourea (ENU) mutagenesis. We found that clinically reported L718 and G796 compound mutations appeared, consistent with their proximity to the binding site of brigatinib, and brigatinib-resistant quadruple mutants such as EGFR-activating mutation/T790M/C797S/L718M were resistant to all the clinically available EGFR-TKIs. BI-4020, a fourth-generation EGFR inhibitor with a macrocyclic structure, overcomes the quadruple and major EGFR-activating mutants but not the minor mutants, such as L747P or S768I. Molecular dynamics simulation revealed the binding mode and affinity between BI-4020 and EGFR mutants. This study identified potential therapeutic strategies using the new-generation macrocyclic EGFR inhibitor to overcome the emerging ultimate resistance mutants., (© 2024. The Author(s).)