The nuclear lamina (NL) lines the nuclear envelope (NE) to maintain nuclear structure in metazoan cells. The major NL components, the nuclear lamins contribute to the protection against NE rupture induced by mechanical stress. Lamin A (LA) and a short form of the splicing variant lamin C (LC) are diffused from the nucleoplasm to sites of NE rupture in immortalized mouse embryonic fibroblasts (MEFs).
View Article and Find Full Text PDFThe hard disk medium (HDM) with a carbon overcoat (COC) is a fundamental component of a hard disk drive. The conventional test for its corrosion durability, known as the "HOT/WET test," requires considerable time and effort and does not provide any local information about the corrosion. Here, we address this issue by employing open-loop electric potential microscopy (OL-EPM), a potential measurement technique based on atomic force microscopy (AFM), for corrosion inspection.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
November 2024
Microbial surfaces play a critical role in various biological processes including cell adhesion and biofilm formation. Understanding these surfaces at the nanoscale is essential for both fundamental and applied microbiology. This review explores recent advancements in nanoscale structural and chemical analyses of microbial surfaces, with a focus on vibrational spectroscopy, such as Raman spectroscopy, infrared spectroscopy, and atomic force microscopy.
View Article and Find Full Text PDFis a prevalent bacterial taxon in the human gut that comprises over 10 (sub)species. Previous studies suggest that these species use evolutionarily distinct strategies for symbiosis with their hosts. However, the underlying species-specific mechanisms remain unclear due to the lack of efficient gene knockout systems applicable across different species.
View Article and Find Full Text PDFHydration at solid-liquid interfaces plays an essential role in a wide range of phenomena in biology and in materials and Earth sciences. However, the atomic-scale dynamics of hydration have remained elusive because of difficulties associated with their direct visualization. In this work, a high-speed three-dimensional (3D) scanning force microscopy technique that produces 3D images of solid-liquid interfaces with subnanoscale resolution at a rate of 1.
View Article and Find Full Text PDFPromising outcomes have been reported in elder patients with acute myeloid leukemia (AML) using combined therapy of venetoclax (VEN) and azacytidine (AZA) in recent years. However, approximately one-third of patients appear to be refractory to this therapy. Vitamin K2 (VK2) shows apoptosis-inducing activity in AML cells, and daily oral VK2 (menaquinone-4, GlakayR) has been approved for patients with osteoporosis in Japan.
View Article and Find Full Text PDFThe invention of 3D atomic force microscopy (3D-AFM) has enabled visualizing subnanoscale 3D hydration structures. Meanwhile, its applications to imaging flexible molecular chains have started to be experimentally explored. However, the validity and principle of such imaging have yet to be clarified by comparing experiments and simulations or cross-observations with an alternative technique.
View Article and Find Full Text PDFSelf-organizing solid-binding peptides on atomically flat solid surfaces offer a unique bio/nano hybrid platform, useful for understanding the basic nature of biology/solid coupling and their practical applications. The surface behavior of peptides is determined by their molecular folding, which is influenced by various factors and is challenging to study. Here, the effect of charged amino acids is studied on the self-assembly behavior of a directed evolution selected graphite-binding dodecapeptide on graphite surface.
View Article and Find Full Text PDFWe previously reported that macrolide antibiotics, such as clarithromycin (CAM), blocked autophagy flux, and simultaneous proteasome and autophagy inhibition by bortezomib (BTZ) plus CAM resulted in enhanced apoptosis induction in multiple myeloma (MM) cells via increased endoplasmic reticulum (ER) stress loading. However, in actual therapeutic settings, cell adhesion-mediated drug resistance between bone marrow stromal cells (BMSC) and MM cells has been known to be a barrier to treatment. To investigate whether CAM could enhance BTZ-induced cytotoxicity in MM cells under direct cell adhesion with BMSC, we established a co-culture system of EGFP-labeled MM cells with BMSC.
View Article and Find Full Text PDFWater molecules on oxide surfaces influence the chemical reactivity and molecular adsorption behavior of oxides. Herein, three-dimensional atomic force microscopy (3D-AFM) and molecular dynamics simulations are used to visualize the surface hydroxyl (OH) groups and their hydration structures on sapphire (001) and α-quartz (100) surfaces at the atomic-scale. The obtained results revealed that the spatial density distributions and hydrogen-bonding strengths of surface OH groups affect their local hydration structures.
View Article and Find Full Text PDFAtomic force microscopy (AFM) is capable of nanoscale imaging but has so far only been used on cell surfaces when applied to a living cell. Here, we describe a step-by-step protocol for nanoendoscopy-AFM, which enables the imaging of nanoscale structures inside living cells. The protocol consists of cell staining, fabrication of the nanoneedle probes, observation inside living cells using 2D and 3D nanoendoscopy-AFM, and visualization of the 3D data.
View Article and Find Full Text PDFNumerous studies have investigated the various cellular responses against genotoxic stress, including those mediated by focal adhesions. We here identified a novel type of focal adhesion remodelling that occurs under genotoxic stress conditions, which involves the replacement of active focal adhesion kinase (FAK) with FAK-related non-kinase (FRNK). FRNK stabilized focal adhesions, leading to strong cell-matrix adhesion, and FRNK-depleted cells were easily detached from extracellular matrix upon genotoxic stress.
View Article and Find Full Text PDFBackground: Autophagy plays an important role in tumour cell growth and survival and also promotes resistance to chemotherapy. Hence, autophagy has been targeted for cancer therapy. We previously reported that macrolide antibiotics including azithromycin (AZM) inhibit autophagy in various types of cancer cells in vitro.
View Article and Find Full Text PDFLysosomes are single-membraned organelles that mediate the intracellular degradation of macromolecules. Various stress can induce lysosomal membrane permeabilization (LMP), translocating intralysosomal components, such as cathepsins, to the cytoplasm, which induces lysosomal-dependent cell death (LDCD). This study reports that p53 regulates LMP in response to DNA-damaging drugs.
View Article and Find Full Text PDFCellulose, a renewable structural biopolymer, is ubiquitous in nature and is the basic reinforcement component of the natural hierarchical structures of living plants, bacteria, and tunicates. However, a detailed picture of the crystalline cellulose surface at the molecular level is still unavailable. Here, using atomic force microscopy (AFM) and molecular dynamics (MD) simulations, we revealed the molecular details of the cellulose chain arrangements on the surfaces of individual cellulose nanocrystals (CNCs) in water.
View Article and Find Full Text PDFThree-dimensional atomic force microscopy (3D-AFM) has resolved three-dimensional distributions of solvent molecules at solid-liquid interfaces at the subnanometer scale. This method is now being extended to the imaging of biopolymer assemblies such as chromosomes or proteins in cells, with the expectation of being able to resolve their three-dimensional structures. Here, we have developed a computational method to simulate 3D-AFM images of biopolymers by using the Jarzynski equality.
View Article and Find Full Text PDFChemical fixations have been thought to preserve the structures of the cells or tissues. However, given that the fixatives create crosslinks or aggregate proteins, there is a possibility that these fixatives create nanoscale artefacts by aggregation of membrane proteins which move around freely to some extent on the cell surface. Despite this, little research has been conducted about this problem, probably because there has been no method for observing cell surface structures at the nanoscale.
View Article and Find Full Text PDFmutation is one of the most frequent gene mutations in head and neck squamous cell carcinoma (HNSCC) and could be a potential therapeutic target. Recently, the WEE1 G2 checkpoint kinase (WEE1) inhibitor adavosertib (Adv) has attracted attention because of its selective cytotoxicity against ‑mutated cells and has shown promising activity in early phase clinical trials. In the present study, it was demonstrated that combined treatment with Adv and a selective histone deacetylase 6 (HDAC6) inhibitor, ricolinostat (RCS), synergistically enhanced cell death induction in four out of five HNSCC cell lines with mutation (CAL27, SAS, HSC‑3, and OSC‑19), one HNSCC cell line with impaired TP53 function by HPV‑infection (UPCI‑SCC154), and ‑knockout human lung cancer cell line (A549 TP53‑KO), but not in wild‑type A549 cells.
View Article and Find Full Text PDFPancreatic cancer is one of the leading causes of cancer‑related mortality and has the lowest 5‑year survival rate. Therefore, novel strategies are urgently required to treat pancreatic cancer. Pancreatic ductal adenocarcinoma (PDAC) cells rely on enhanced lysosomal function for survival and proliferation to facilitate the degradation of contents accumulated via autophagy and macropinocytosis.
View Article and Find Full Text PDFAtomic force microscopy (AFM) is the only technique that allows label-free imaging of nanoscale biomolecular dynamics, playing a crucial role in solving biological questions that cannot be addressed by other major bioimaging tools (fluorescence or electron microscopy). However, such imaging is possible only for systems either extracted from cells or reconstructed on solid substrates. Thus, nanodynamics inside living cells largely remain inaccessible with the current nanoimaging techniques.
View Article and Find Full Text PDFThe autophagy‑lysosome system allows cells to adapt to environmental changes by regulating the degradation and recycling of cellular components, and to maintain homeostasis by removing aggregated proteins and defective organelles. Cyclin G‑associated kinase (GAK) is involved in the regulation of clathrin‑dependent endocytosis and cell cycle progression. In addition, a single nucleotide polymorphism at the GAK locus has been reported as a risk factor for Parkinson's disease.
View Article and Find Full Text PDFFollowing surgery and chemoradiation, ~50% of patients with locally advanced head and neck tumors experience relapse within the first two years, with a poor prognosis. Therefore, a novel therapeutic approach is required. The aim of the present study was to investigate the effect of combination treatment with the proteasome inhibitor bortezomib (BTZ), and ricolinostat (RCS), a specific inhibitor of histone deacetylase 6 (HDAC6), on CAL27 and Detroit562 head and neck cancer cells.
View Article and Find Full Text PDFCancer cells use autophagy for growth, survival, and cytoprotection from chemotherapy. Therefore, autophagy inhibitors appear to be good candidates for cancer treatment. Our group previously reported that macrolide antibiotics, especially azithromycin (AZM), have potent autophagy inhibitory effects, and combination treatment with tyrosine kinase inhibitors or proteasome inhibitors enhances their anti-cancer activity.
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