Yeast-derived particulate beta-glucan induced angiogenesis via regulating PI3K/Src and ERK1/2 signaling pathway

The importance of β-glucan from S. cerevisiae in angiogenesis has not been well studied. We investigated whether β-glucan induces angiogenesis through PI3K/Src and ERK1/2 signaling pathway in HUVECs. We identified that β-glucan induced phosphorylation of PI3K, Src, Akt, eNOS, and ERK1/2. Subsequently, we found that this phosphorylation increased the viability of HUVECs. We also observed that stimulation of β-glucan promoted the activity of MEF2 and MEF2-dependent pro-angiogenic genes, including EGR2, EGR3, KLF2, and KLF4. Additionally, the role of β-glucan in angiogenesis was confirmed using in vitro and ex vivo experiments including cell migration, capillary-like tube formation and mouse aorta ring assays. To determine the effect of β-glucan on the PI3K/Akt/eNOS and ERK1/2 signaling pathway, PI3K inhibitor wortmannin and ERK1/2 inhibitor SCH772984 were used. Through the Matrigel plug assay, we confirmed that β-glucan significantly increased angiogenesis in vivo. Taken together, our study demonstrates that β-glucan promotes angiogenesis via through PI3K and ERK1/2 signaling pathway.

PIBF1 regulates trophoblast syncytialization and promotes cardiovascular development

Proper placental development in early pregnancy ensures a positive outcome later on. The developmental relationship between the placenta and embryonic organs, such as the heart, is crucial for a normal pregnancy. However, the mechanism through which the placenta influences the development of embryonic organs remains unclear. Trophoblasts fuse to form multinucleated syncytiotrophoblasts (SynT), which primarily make up the placental materno-fetal interface. We discovered that endogenous progesterone immunomodulatory binding factor 1 (PIBF1) is vital for trophoblast differentiation and fusion into SynT in humans and mice. PIBF1 facilitates communication between SynT and adjacent vascular cells, promoting vascular network development in the primary placenta. This process affected the early development of the embryonic cardiovascular system in mice. Moreover, in vitro experiments showed that PIBF1 promotes the development of cardiovascular characteristics in heart organoids. Our findings show how SynTs organize the barrier and imply their possible roles in supporting embryogenesis, including cardiovascular development. SynT-derived factors and SynT within the placenta may play critical roles in ensuring proper organogenesis of other organs in the embryo.

Understanding the molecular mechanism of pathogenic variants of BIR2 domain in XIAP-deficient inflammatory bowel disease

X-linked inhibitor of apoptosis protein (XIAP) deficiency causes refractory inflammatory bowel disease. The XIAP protein plays a pivotal role in the pro-inflammatory response through the nucleotide-binding oligomerization domain-containing signaling pathway that is important in mucosal homeostasis. We analyzed the molecular mechanism of non-synonymous pathogenic variants (PVs) of XIAP BIR2 domain. We generated N-terminally green fluorescent protein-tagged XIAP constructs of representative non-synonymous PVs. Co-immunoprecipitation and fluorescence cross-correlation spectroscopy showed that wild-type XIAP and RIP2 preferentially interacted in live cells, whereas all non-synonymous PV XIAPs failed to interact properly with RIP2. Structural analysis showed that various structural changes by mutations, such as hydrophobic core collapse, Zn-finger loss, and spatial rearrangement, destabilized the two loop structures (174-182 and 205-215) that critically interact with RIP2. Subsequently, it caused a failure of RIP2 ubiquitination and loss of protein deficiency by the auto-ubiquitination of all XIAP mutants. These findings could enhance our understanding of the role of XIAP mutations in XIAP-deficient inflammatory bowel disease and may benefit future therapeutic strategies.

HDAC5-mediated exosomal Maspin and miR-151a-3p as biomarkers for enhancing radiation treatment sensitivity in hepatocellular carcinoma

BACKGROUND

Tumor-derived exosomes are critical elements of the cell-cell communication response to various stimuli. This study aims to reveal that the histone deacetylase 5 (HDAC5) and p53 interaction upon radiation in hepatocellular carcinoma intricately regulates the secretion and composition of exosomes.

METHODS

We observed that HDAC5 and p53 expression were significantly increased by 2 Gy and 4 Gy radiation exposure in HCC. Normal- and radiation-derived exosomes released by HepG2 were purified to investigate the exosomal components.

RESULTS

We found that in the radiation-derived exosome, exosomal Maspin was notably increased. Maspin is known as an anti-angiogenic gene. The expression of Maspin was regulated at the cellular level by HDAC5, and it was elaborately regulated and released in the exosome. Radiation-derived exosome treatment caused significant inhibition of angiogenesis in HUVECs and mouse aortic tissues. Meanwhile, we confirmed that miR-151a-3p was significantly reduced in the radiation-derived exosome through exosomal miRNA sequencing, and three HCC-specific exosomal miRNAs were also decreased. In particular, miR-151a-3p induced an anti-apoptotic response by inhibiting p53, and it was shown to induce EMT and promote tumor growth by regulating p53-related tumor progression genes. In the HCC xenograft model, radiation-induced exosome injection significantly reduced angiogenesis and tumor size.

CONCLUSIONS

Our present findings demonstrated HDAC5 is a vital gene of the p53-mediated release of exosomes resulting in tumor suppression through anti-cancer exosomal components in response to radiation. Finally, we highlight the important role of exosomal Maspin and mi-151a-3p as a biomarker in enhancing radiation treatment sensitivity. Therapeutic potential of HDAC5 through p53-mediated exosome modulation in radiation treatment of hepatocellular carcinoma.

Identification of exosomal microRNA panel as diagnostic and prognostic biomarker for small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) has an exceptionally poor prognosis; as most of the cases are initially diagnosed as extensive disease with hematogenous metastasis. Therefore, the early diagnosis of SCLC is very important and may improve its prognosis.

METHODS

To investigate the feasibility of early diagnosis of SCLC, we examined exosomal microRNAs (miRNAs) present in serum obtained from patients with SCLC. First, exosomes were isolated in serum from patients with SCLC and healthy individuals and were characterized using particle size and protein markers. Additionally, miRNA array was performed to define SCLC-specific exosomal miRNAs. Second, the obtained miRNAs were further validated employing a large cohort. Finally, the ability to diagnose SCLC was estimated by area under the curve (AUC), and intracellular mRNA change patterns were verified through validated miRNAs.

RESULTS

From the miRNA array results, we selected 51-miRNAs based on p-values and top 10 differentially expressed genes, and 25-miRNAs were validated using quantitative reverse transcription-polymerase chain reaction. The 25-miRNAs were further validated employing a large cohort. Among them, 7-miRNAs showed significant differences. Furthermore, 6-miRNAs (miR-3565, miR-3124-5p, miR-200b-3p, miR-6515, miR-3126-3p and miR-9-5p) were up-regulated and 1-miRNA (miR-92b-5p) was down-regulated. The AUC value of each miRNA sets between 0.64 and 0.76, however the combined application of 3-miRNAs (miR-200b-3p, miR-3124-5p and miR-92b-5p) remarkably improved the diagnostic value (AUC = 0.93). Gene ontology analysis revealed that the 3-miRNA panel is linked to various oncogene pathways and nervous system development. When the 3-miRNAs were introduced to cells, the resulting changes in total mRNA expression strongly indicated the presence of lung diseases, including lung cancer. In addition, the 3-miRNA panel was significantly associated with a poorer prognosis, although individual miRNAs have not been validated as prognostic markers.

CONCLUSION

Our study identified SCLC-specific exosomal miRNAs, and the 3-miRNAs panel (miR-200b-3p, miR-3124-5p and miR-92b-5p) may serve as a diagnostic and prognostic marker for SCLC.

Influence of Chemical and Genetic Manipulations on Cellular Organelles Quantified by Label-Free Optical Diffraction Tomography

Label-free optical diffraction tomography provides three-dimensional imaging of cells and organelles, along with their refractive index (RI) and volume. These physical parameters are valuable for quantitative and accurate analysis of the subcellular microenvironment and its connections to intracellular biological properties. In biological and biochemical cell analysis, various invasive cell manipulations are used, such as temperature change, chemical fixation, live cell staining with fluorescent dye, and gene overexpression of exogenous proteins. However, it is not fully understood how these various manipulations affect the physicochemical properties of different organelles. In this study, we investigated the impact of these manipulations on the cellular properties of single HeLa cells. We found that after cell fixation and an increase in temperature, the RI value of organelles, such as the nucleus and cytoplasm, significantly decreased overall. Interestingly, unlike the cell nuclei, cytoplasmic RI values were hardly detected after membrane permeation, indicating that only intracytoplasmic components were largely lost. Additionally, our findings revealed that the expression of GFP and GFP-tagged proteins significantly increased the RI values of organelles in living cells compared to the less effective RI changes observed with chemical fluorescence staining for cell organelles. The result demonstrates that distinct types of invasive manipulations can alter the microenvironment of organelles in different ways. Our study sheds new light on how chemical and genetic manipulations affect organelles.

Monoclonal antibody Y01 prevents tauopathy progression induced by lysine280-acetylated tau in cell and mouse models

The spatiotemporal pattern of the spread of pathologically modified tau through brain regions in Alzheimer's disease (AD) can be explained by prion-like cell-to-cell seeding and propagation of misfolded tau aggregates. Hence, to develop targeted therapeutic antibodies, it is important to identify the seeding- and propagation-competent tau species. The hexapeptide 275VQIINK280 of tau is a critical region for tau aggregation, and K280 is acetylated in various tauopathies including AD. However, the mechanism that links tau acetylated on lysine 280 (tau-acK280) to subsequent progression to neurodegenerative disease remains unclear. Here, we demonstrate that tau-acK280 is critical for tau propagation processes including secretion, aggregation, and seeding. We developed an antibody, Y01, that specifically targets tau-acK280 and solved the crystal structure of Y01 in complex with an acK280 peptide. The structure confirmed that Y01 directly recognizes acK280 and the surrounding residues. Strikingly, upon interaction with acetylated tau aggregates, Y01 prevented tauopathy progression and increased neuronal viability in neuron cultures and in tau transgenic mice through antibody-mediated neutralization and phagocytosis, respectively. Based on our observations that tau-acK280 is a core species involved in seeding and propagation activities, the Y01 antibody that specifically recognizes acK280 represents a promising therapeutic candidate for AD and other neurodegenerative diseases associated with tauopathy.

Frequent Intraluminal Growth of Large Muscular Veins in Surgically Resected Colorectal Cancer Tissues: A 3-Dimensional Pathologic Reconstruction Study

Although venous invasion (VI) is common in colorectal cancers (CRCs) and is associated with distant metastasis, the 3-dimensional (3D) microscopic features and associated mechanisms of VI are not well elucidated. To characterize the patterns of VI, 103 tissue slabs were harvested from surgically resected CRCs with ≥pT2. They were cleared using the modified immunolabeling-enabled 3D imaging of solvent-cleared organs method, labeled with multicolor fluorescent antibodies, including antibodies against cytokeratin 19, desmin, CD31, and E-cadherin, and visualized by confocal laser scanning microscopy. VI was classified as intravasation, intraluminal growth, and/or extravasation, and 2-dimensional and 3D microscopic features were compared. VI was detected more frequently in 3D (56/103 [54.4%]) than in conventional 2-dimensional hematoxylin and eosin-stained slides (33/103 [32%]; P < .001). When VI was present, it was most commonly in the form of intraluminal growth (51/56), followed by extravasation (13/56) and intravasation (5/56). The mean length of intraluminal growth was 334.0 ± 212.4 μm. Neoplastic cell projections extended from cancer cell clusters in the connective tissue surrounding veins, penetrated the smooth muscle layer, and then grew into and filled the venous lumen. E-cadherin expression changed at each invasion phase; intact E-cadherin expression was observed in the cancer cells in the venous walls, but its expression was lost in small clusters of intraluminal neoplastic cells. In addition, reexpression of E-cadherin was observed when cancer cells formed well-oriented tubular structures and accumulated and grew along the luminal side of the venous wall. In contrast, singly scattered cancer cells and cancer cells with poorly defined tubular structures showed loss of E-cadherin expression. E-cadherin expression was intact in the large cohesive clusters of extravasated cancer cells. However, singly scattered cells and smaller projections of neoplastic cells in the stroma outward of venous wall showed a loss of E-cadherin expression. In conclusion, VI was observed in more than half of the CRCs analyzed by 3D histopathologic image reconstruction. Once inside a vein, neoplastic cells can grow intraluminally. The epithelial-mesenchymal transition is not maintained during VI of CRCs.

Angiogenic adipokine C1q-TNF-related protein 9 ameliorates myocardial infarction via histone deacetylase 7-mediated MEF2 activation

C1q/tumor necrosis factor-related protein 9 (CTRP9) is an adipokine and has high potential as a therapeutic target. However, the role of CTRP9 in cardiovascular disease pathogenesis remains unclear. We found CTRP9 to induce HDAC7 and p38 MAPK phosphorylation via tight regulation of AMPK in vascular endothelial cells, leading to angiogenesis through increased MEF2 activity. The expression of CTRP9 and atheroprotective MEF2 was decreased in plaque tissue of atherosclerotic patients and the ventricle of post-infarction mice. CTRP9 treatment inhibited the formation of atherosclerotic plaques in ApoE KO and CTRP9 KO mice. In addition, CTRP9 induced significant ischemic injury prevention in the post-MI mice. Clinically, serum CTRP9 levels were reduced in patients with MI compared with healthy controls. In summary, CTRP9 induces a vasoprotective response via the AMPK/HDAC7/p38 MAPK pathway in vascular endothelial cells, whereas its absence can contribute to atherosclerosis and MI. Hence, CTRP9 may represent a valuable therapeutic target and biomarker in cardiovascular diseases.

Urinary Exosomal Cystatin C and Lipopolysaccharide Binding Protein as Biomarkers for Antibody−Mediated Rejection after Kidney Transplantation

We aimed to discover and validate urinary exosomal proteins as biomarkers for antibody−mediated rejection (ABMR) after kidney transplantation. Urine and for-cause biopsy samples from kidney transplant recipients were collected and categorized into the discovery cohort (n = 36) and a validation cohort (n = 65). Exosomes were isolated by stepwise ultra-centrifugation for proteomic analysis to discover biomarker candidates for ABMR (n = 12). Of 1820 exosomal proteins in the discovery cohort, four proteins were specifically associated with ABMR: cystatin C (CST3), serum paraoxonase/arylesterase 1, retinol-binding protein 4, and lipopolysaccharide−binding protein (LBP). In the validation cohort, the level of urinary exosomal LBP was significantly higher in the ABMR group (n = 25) compared with the T-cell-mediated rejection (TCMR) group and the no major abnormality (NOMOA) group. Urinary exosomal CST3 level was significantly higher in the ABMR group compared with the control and NOMOA groups. Immunohistochemical staining showed that LBP and CST3 in the glomerulus were more abundant in the ABMR group compared with other groups. The combined prediction probability of urinary exosomal LBP and CST3 was significantly correlated with summed LBP and CST3 intensity scores in the glomerulus and peritubular capillary as well as Banff g + ptc scores. Urinary exosomal CST3 and LBP could be potent biomarkers for ABMR after kidney transplantation.

Clusterin Binding Modulates the Aggregation and Neurotoxicity of Amyloid-β(1-42)

Alzheimer's disease (AD) is the most common neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) aggregates in the brain. Clusterin (CLU), also known as apolipoprotein J, is a potent risk factor associated with AD pathogenesis, in which Aβ aggregation is essentially involved. We observed close colocalization of CLU and Aβ(1-42) (Aβ42) in parenchymal amyloid plaques or vascular amyloid deposits in the brains of human amyloid precursor protein (hAPP)-transgenic Tg2576 mice. Therefore, to elucidate the binding interaction between CLU and Aβ42 and its impact on amyloid aggregation and toxicity, the two synthetic proteins were incubated together under physiological conditions, and their structural and morphological variations were investigated using biochemical, biophysical, and microscopic analyses. Synthetic CLU spontaneously bound to different possible variants of Aβ42 aggregates with very high affinity (Kd = 2.647 nM) in vitro to form solid CLU-Aβ42 complexes. This CLU binding prevented further aggregation of Aβ42 into larger oligomers or fibrils, enriching the population of smaller Aβ42 oligomers and protofibrils and monomers. CLU either alleviated or augmented Aβ42-induced cytotoxicity and apoptosis in the neuroblastoma-derived SH-SY5Y and N2a cells, depending on the incubation period and the molar ratio of CLU:Aβ42 involved in the reaction before addition to the cells. Thus, the effects of CLU on Aβ42-induced cytotoxicity were likely determined by the extent to which it bound and sequestered toxic Aβ42 oligomers or protofibrils. These findings suggest that CLU could influence amyloid neurotoxicity and pathogenesis by modulating Aβ aggregation.

Yeast beta-glucan mediates histone deacetylase 5-induced angiogenesis in vascular endothelial cells

The role of yeast-derived β-glucan in angiogenesis has not been elucidated because there have been few specific studies on its clinical and physiological significance. Therefore, this study investigated the correlation between β-glucan and histone deacetylase 5 (HDAC5) in human umbilical vein endothelial cells (HUVECs), revealing the role of β-glucan in angiogenesis. We confirmed that HDAC5 was phosphorylated by β-glucan stimulation and released from the nucleus to the cytoplasm. Furthermore, we found that β-glucan-stimulated HDAC5 translocation mediates the transcriptional activation of MEF2. As a result, the expression of KLF2, EGR2, and NR4A2, whose expression is MEF2-dependent and involved in angiogenesis, increased. Thus, we showed the activity of β-glucan in angiogenesis through in vitro and ex vivo assays including cell migration, tube formation, and aortic ring analyses. Specifically, application of an HDAC5 inhibitor repressed MEF2 transcriptional activation in both in vitro and ex vivo angiogenesis. HDAC5 inhibitor LMK235 inhibited the proangiogenic activity of beta-glucan, suggesting that β-glucan induces angiogenesis through HDAC5. These findings suggest that HDAC5 is essential for angiogenesis, and that β-glucan induces angiogenesis. In conclusion, this study demonstrates that β-glucan induces angiogenesis through HDAC5. It also suggests that β-glucan has potential value as a novel therapeutic agent for modulating angiogenesis.

FTIR study of the surface-ligand exchange reaction with glutathione on biocompatible rod-shaped CdSe/CdS semiconductor nanocrystals

Semiconductor nanocrystals (SNCs) are an essential optical tool in the life sciences. Application of SNCs to living systems requires that their surfaces be covered with biocompatible molecules. The surface capping...

Characterizing Organelles in Live Stem Cells Using Label-Free Optical Diffraction Tomography

Label-free optical diffraction tomography (ODT), an imaging technology that does not require fluorescent labeling or other pre-processing, can overcome the limitations of conventional cell imaging technologies, such as fluorescence and electron microscopy. In this study, we used ODT to characterize the cellular organelles of three different stem cells-namely, human liver derived stem cell, human umbilical cord matrix derived mesenchymal stem cell, and human induced pluripotent stem cell-based on their refractive index and volume of organelles. The physical property of each stem cell was compared with that of fibroblast. Based on our findings, the characteristic physical properties of specific stem cells can be quantitatively distinguished based on their refractive index and volume of cellular organelles. Altogether, the method employed herein could aid in the distinction of living stem cells from normal cells without the use of fluorescence or specific biomarkers.

Application of quantitative cell imaging using label-free optical diffraction tomography

The cell is three-dimensionally and dynamically organized into cellular compartments, including the endoplasmic reticulum, mitochondria, vesicles, and nucleus, which have high relative molecular density. The structure and functions of these compartments and organelles may be deduced from the diffusion and interaction of related biomolecules. Among these cellular components, various protein molecules can freely access the nucleolus or mitotic chromosome through Brownian diffusion, even though they have a densely packed structure. However, physicochemical properties of the nucleolus and chromosomes, such as molecular density and volume, are not yet fully understood under changing cellular conditions. Many studies have been conducted based on high-resolution imaging and analysis techniques using fluorescence. However, there are limitations in imaging only fluorescently labeled molecules, and cytotoxicity occurs during three-dimensional imaging. Alternatively, the recently developed label-free three-dimensional optical diffraction tomography (ODT) imaging technique can divide various organelles in cells into volumes and analyze them by refractive index, although specific molecules cannot be observed. A previous study established an analytical method that provides comprehensive insights into the physical properties of the nucleolus and mitotic chromosome by utilizing the advantages of ODT and fluorescence techniques, such as fluorescence correlation spectroscopy and confocal laser scanning microscopy. This review article summarizes a recent study and discusses the future aspects of the ODT for cellular compartments.

Smart Vitamin Micelles as Cancer Nanomedicines for Enhanced Intracellular Delivery of Doxorubicin

Chemotherapy is one of the most effective treatments for cancer. However, intracellular delivery of many anticancer drugs is hindered by their hydrophobicity and low molecular weight. Here, we describe highly biocompatible and biodegradable amphiphilic vitamin conjugates comprising hydrophobic vitamin E and hydrophilic vitamin B labeled with dual pH and glutathione-responsive degradable linkages. Vitamin-based micelles (vitamicelles), formed by self-assembly in aqueous solutions, were optimized based on their stability after encapsulation of doxorubicin (DOX). The resulting vitamicelles have great potential as vehicles for anticancer drugs because they show excellent biocompatibility (>94% after 48 h of incubation) and rapid biodegradability (>90% after 2.5 h). Compared with free DOX, DOX-loaded vitamicelles showed a markedly enhanced anticancer effect as they released the drug rapidly and inhibited drug efflux out of cells efficiently. By exploiting these advantages, this study not only provides a promising strategy for circumventing existing challenges regarding the delivery of anticancer drugs but also extends the utility of current DOX-induced chemotherapy.

Interpretation of XIAP Variants of Uncertain Significance in Paediatric Patients with Refractory Crohn's Disease

BACKGROUND AND AIMS

Mutations in XIAP can lead to the development of treatment-refractory severe paediatric Crohn's disease [CD], for which haematopoietic stem cell transplantation is the primary therapeutic option. The interpretation of variants of uncertain significance [VUSs] in XIAP needs to be scrutinized.

METHODS

Targeted next-generation sequencing was performed for 33 male paediatric patients with refractory CD admitted at a tertiary referral hospital. To obtain functional data, biomolecular cell assays and supercomputing molecular dynamics simulations were performed.

RESULTS

Nine unrelated male patients harboured hemizygous XIAP variants. Four known pathogenic variants and one novel pathogenic variant [p.Lys168Serfs*12] were identified in five patients, and two novel VUSs [p.Gly205del and p.Pro260Ser] and one known VUS [p.Glu350del] were identified in the remaining four. Among children with VUSs, only the subject with p.Gly205del exhibited defective NOD2 signalling. Using molecular dynamics simulation, we determined that the altered backbone torsional energy of C203 in XIAP of p.G205del was ~2 kcal/mol, suggesting loss of zinc binding in the mutant XIAP protein and poor coordination between the mutant XIAP and RIP2 proteins. Elevated auto-ubiquitination of zinc-depleted p.G205del XIAP protein resulted in XIAP protein deficiency.

CONCLUSION

A high prevalence of XIAP deficiency was noted among children with refractory CD. Advanced functional studies decreased the subjectivity in the case-level interpretation of XIAP VUSs and directed consideration of haematopoietic stem cell transplantation.

Quantitative analyses reveal extracellular dynamics of Wnt ligands in Xenopus embryos

The mechanism of intercellular transport of Wnt ligands is still a matter of debate. To better understand this issue, we examined the distribution and dynamics of Wnt8 in Xenopus embryos. While Venus-tagged Wnt8 was found on the surfaces of cells close to Wnt-producing cells, we also detected its dispersal over distances of 15 cell diameters. A combination of fluorescence correlation spectroscopy and quantitative imaging suggested that only a small proportion of Wnt8 ligands diffuses freely, whereas most Wnt8 molecules are bound to cell surfaces. Fluorescence decay after photoconversion showed that Wnt8 ligands bound on cell surfaces decrease exponentially, suggesting a dynamic exchange of bound forms of Wnt ligands. Mathematical modeling based on this exchange recapitulates a graded distribution of bound, but not free, Wnt ligands. Based on these results, we propose that Wnt distribution in tissues is controlled by a dynamic exchange of its abundant bound and rare free populations.

SLAC2B-dependent microtubule acetylation regulates extracellular matrix-mediated intracellular TM4SF5 traffic to the plasma membranes

Transmembrane 4 L six family member 5 (TM4SF5) translocates intracellularly and promotes cell migration, but how subcellular TM4SF5 traffic is regulated to guide cellular migration is unknown. We investigated the influences of the extracellular environment and intracellular signaling on the TM4SF5 traffic with regard to migration directionality. Cell adhesion to fibronectin (FN) but not poly-l-lysine enhanced the traffic velocity and straightness of the TM4SF5_WT (but not palmitoylation-deficient mutant TM4SF5 Pal - ) toward the leading edges, depending on tubulin acetylation. Acetylated-microtubules in SLAC2B-positive cells reached mostly the juxtanuclear regions, but reached-out toward the leading edges upon SLAC2B suppression. TM4SF5 expression caused SLAC2B not to be localized at the leading edges. TM4SF5 colocalization with HDAC6 depended on paxillin expression. The trimeric complex consisting of TM4SF5, HDAC6, and SLAC2B might, thus, be enriched at the perinuclear cytosols toward the leading edges. More TM4SF5_WT translocation to the leading edges was possible when acetylated-microtubules reached the frontal edges following HDAC6 inhibition by paxillin presumably at new cell-FN adhesions, leading to persistent cell migration. Collectively, this study revealed that cell-FN adhesion and microtubule acetylation could control intracellular traffic of TM4SF5 vesicles to the leading edges via coordinated actions of paxillin, SLAC2B, and HDAC6, leading to TM4SF5-dependent cell migration.

Variably Sized and Multi-Colored Silica-Nanoparticles Characterized by Fluorescence Correlation Methods for Cellular Dynamics

Controlling the uptake of nanoparticles into cells so as to balance therapeutic effects with toxicity is an essential unsolved problem in the development of nanomedicine technologies. From this point of view, it is useful to use standard nanoparticles to quantitatively evaluate the physical properties of the nanoparticles in solution and in cells, and to analyze the intracellular dynamic motion and distribution of these nanoparticles at a single-particle level. In this study, standard nanoparticles are developed based on a variant silica-based nanoparticle incorporating fluorescein isothiocyanate (FITC) or/and rhodamine B isothiocyanate (RITC) with a variety of accessible diameters and a matching fluorescent cobalt ferrite core-shell structure (Fe₂O₄/SiO₂). The physical and optical properties of the nanoparticles in vitro are fully evaluated with the complementary methods of dynamic light scattering, electron microscopy, and two fluorescence correlation methods. In addition, cell uptake of dual-colored and core/shell nanoparticles via endocytosis in live HeLa cells is detected by fluorescence correlation spectroscopy and electron microscopy, indicating the suitability of the nanoparticles as standards for further studies of intracellular dynamics with multi-modal methods.

SERS Effect on Spin-Coated Seeding of Tilted Au-ZnO Nanorods for Low-Cost Diagnosis

Uniformly parallel Au-coated ZnO nanorods have previously been shown to amplify local Raman signals, providing increased sensitivity to disease markers in the detection of inflammation and cancer. However, practical and cost-effective fabrication methods of substrates for surface-enhanced Raman spectroscopy (SERS) fail to produce highly uniform surfaces. Here, the feasibility of Raman enhancement on less-uniform substrates is assessed. ZnO nanorod structures were fabricated by hydrothermal synthesis, starting from spin-coated seed substrates. Following analysis, the nanostructures were coated with Au to create stochastically variant substrates. The non-uniformity of the fabricated Au-coated ZnO nanorod structures is confirmed morphologically by FE-SEM and structurally by X-ray diffraction, and characterized by the angular distributions of the nanorods. Monte Carlo finite element method simulations matching the measured angular distributions and separations predicted only moderate increases in the overall Raman enhancement with increasing uniformity. Highly variant substrates exhibited approximately 76% of the Raman enhancement of more uniform substrates in simulations and experiments. The findings suggest that, although highly inhomogeneous Au-coated ZnO nanorod substrates may not attain the same Raman enhancement as more uniform substrates, the relaxation of fabrication tolerances may be economically viable.

RNA-binding protein NONO contributes to cancer cell growth and confers drug resistance as a theranostic target in TNBC

Breast cancer (BC) is one of the most common cancers in women. TNBC (Triple-negative breast cancer) has limited treatment options and still lacks viable molecular targets, leading to poor outcomes. Recently, RNA-binding proteins (RBPs) have been shown to play crucial roles in human cancers, including BC, by modulating a number of oncogenic phenotypes. This suggests that RBPs represent potential molecular targets for BC therapy.

Methods: We employed genomic data to identify RBPs specifically expressed in TNBC. NONO was silenced in TNBC cell lines to examine cell growth, colony formation, invasion, and migration. Gene expression profiles in NONO-silenced cells were generated and analyzed. A high-throughput screening for NONO-targeted drugs was performed using an FDA-approved library.

Results: We found that the NONO RBP is highly expressed in TNBC and is associated with poor patient outcomes. NONO binds to STAT3 mRNA, increasing STAT3 mRNA levels in TNBC. Surprisingly, NONO directly interacts with STAT3 protein increasing its stability and transcriptional activity, thus contributing to its oncogenic function. Importantly, high-throughput drug screening revealed that auranofin is a potential NONO inhibitor and inhibits cell growth in TNBC.

Conclusions: NONO is an RBP upstream regulator of both STAT3 RNA and protein levels and function. It represents an important and clinically relevant promoter of growth and resistance of TNBCs. NONO is also therefore a potential therapeutic target in TNBC.

Advances in Analysis of Biodistribution of Exosomes by Molecular Imaging

Exosomes are nano-sized membranous vesicles produced by nearly all types of cells. Since exosome-like vesicles are produced in an evolutionarily conserved manner for information and function transfer from the originating cells to recipient cells, an increasing number of studies have focused on their application as therapeutic agents, drug delivery vehicles, and diagnostic targets. Analysis of the in vivo distribution of exosomes is a prerequisite for the development of exosome-based therapeutics and drug delivery vehicles with accurate prediction of therapeutic dose and potential side effects. Various attempts to evaluate the biodistribution of exosomes obtained from different sources have been reported. In this review, we examined the current trends and the advantages and disadvantages of the methods used to determine the biodistribution of exosomes by molecular imaging. We also reviewed 29 publications to compare the methods employed to isolate, analyze, and label exosomes as well as to determine the biodistribution of labeled exosomes.

Large-scale analysis of diffusional dynamics of proteins in living yeast cells using fluorescence correlation spectroscopy

In the living cells, the majority of proteins does not work alone, but interact with other proteins or other biomolecules to maintain the cellular function, constituting a "protein community". Previous efforts on mass spectroscopy-based protein interaction networks, interactomes, have provided a picture on the protein community. However, these were static information after cells were disrupted. For a better understanding of the protein community in cells, it is important to know the properties of intracellular dynamics and interactions. Since hydrodynamic size and mobility of proteins are related into such properties, direct measurement of diffusional motion of proteins in single living cells will be helpful for uncovering the properties. Here we completed measurement of the diffusion and homo-oligomeric properties of 369 cytoplasmic GFP-fusion proteins in living yeast Saccharomyces cerevisiae cells using fluorescence correlation spectroscopy (FCS). The large-scale analysis showed that the motions of majority of proteins obeyed a two-component (i.e. slow and fast components) diffusion model. Remarkably, both of the two components diffused more slowly than expected monomeric states. In addition, further analysis suggested that more proteins existed as homo-oligomeric states in living cells than previously expected. Our study, which characterizes the dynamics of proteins in living cells on a large-scale, provided a global view on intracellular protein dynamics to understand the protein community.

Mitotic Chromosomes in Live Cells Characterized Using High-Speed and Label-Free Optical Diffraction Tomography

The cell nucleus is a three-dimensional, dynamic organelle organized into subnuclear compartments such as chromatin and nucleoli. The structure and function of these compartments are maintained by diffusion and interactions between related factors as well as by dynamic and structural changes. Recent studies using fluorescent microscopic techniques suggest that protein factors can access and are freely mobile in heterochromatin and in mitotic chromosomes, despite their densely packed structure. However, the physicochemical properties of the chromosome during cell division are not fully understood. In the present study, characteristic properties such as the refractive index (RI), volume of the mitotic chromosomes, and diffusion coefficient (D) of fluorescent probes inside the chromosome were quantified using an approach combining label-free optical diffraction tomography with complementary confocal laser-scanning microscopy and fluorescence correlation spectroscopy. Variations in these parameters correlated with osmotic conditions, suggesting that changes in RI are consistent with those of the diffusion coefficient for mitotic chromosomes and cytosol. Serial RI tomography images of chromosomes in live cells during mitosis were compared with three-dimensional confocal micrographs to demonstrate that compaction and decompaction of chromosomes induced by osmotic change were characterized by linked changes in chromosome RI, volume, and the mobilities of fluorescent proteins.

Physicochemical Properties of Nucleoli in Live Cells Analyzed by Label-Free Optical Diffraction Tomography

The cell nucleus is three-dimensionally and dynamically organized by nuclear components with high molecular density, such as chromatin and nuclear bodies. The structure and functions of these components are represented by the diffusion and interaction of related factors. Recent studies suggest that the nucleolus can be assessed using various protein probes, as the probes are highly mobile in this organelle, although it is known that they have a densely packed structure. However, physicochemical properties of the nucleolus itself, such as molecular density and volume when cellular conditions are changed, are not yet fully understood. In this study, physical parameters such as the refractive index (RI) and volume of the nucleoli in addition to the diffusion coefficient (D) of fluorescent probe protein inside the nucleolus are quantified and compared by combining label-free optical diffraction tomography (ODT) with confocal laser scanning microscopy (CLSM)-based fluorescence correlation spectroscopy (FCS). 3D evaluation of RI values and corresponding RI images of nucleoli in live HeLa cells successfully demonstrated varying various physiological conditions. Our complimentary method suggests that physical property of the nucleolus in live cell is sensitive to ATP depletion and transcriptional inhibition, while it is insensitive to hyper osmotic pressure when compared with the cytoplasm and nucleoplasm. The result demonstrates that the nucleolus has unique physicochemical properties when compared with other cellular components.

Novel Compound Heterozygote Mutation in IL10RA in a Patient With Very Early-Onset Inflammatory Bowel Disease

BACKGROUND

Very early-onset inflammatory bowel disease (VEO-IBD) is often associated with monogenetic disorders. IL-10RA deficiency is one of the major causal mutations in VEO-IBD. Here, we aimed to identify the causal mutation associated with severe IBD in a 1-year-old patient, validate the pathogenicity of the mutation, and characterize the mutant protein.

METHODS

To identify the causal mutation, targeted exome sequencing (ES) was performed using the genomic DNA from the patient. To validate the pathogenicity, IL-10RA functional tests were performed using the patient's peripheral blood mononuclear cells (PBMCs). Additionally, flow cytometry analysis, confocal microscopy on overexpressed green fluorescent protein-fused mutants, and computational analysis on the structures of IL-10RA proteins were performed.

RESULTS

We identified a novel compound heterozygote mutation p.[Tyr91Cys];[Pro146Alafs*40] in the IL10RA gene of the patient. The missense variant p.Tyr91Cys was previously identified but not functionally tested, and a frameshift variant, p.Pro146Alafs*40, is novel and nonfunctional. PBMCs from the patient showed defective signal transducer and activator of transcription 3 activation. The p.Tyr91Cys mutant protein failed to properly localize on the plasma membrane. The p.Tyr91Cys mutation seems to disrupt the hydrophobic core structure surrounding the tyrosine 91 residue, causing structural instability.

CONCLUSIONS

Targeted ES and linkage analysis identified novel compound heterozygous mutations p.[Tyr91Cys];[Pro146Alafs*40] in the IL10RA gene of a child with severe VEO-IBD. p.Tyr91Cys proteins were functionally defective in IL-10RA signaling and failed to properly localize on the plasma membrane, probably due to its structural instability.

Diagnosis in a Preclinical Model of Bladder Pain Syndrome Using a Au/ZnO Nanorod-based SERS Substrate

To evaluate the feasibility of ZnO nanorod-based surface enhanced Raman scattering (SERS) diagnostics for disease models, particularly for interstitial cystitis/bladder pain syndrome (IC/BPS), ZnO-based SERS sensing chips were developed and applied to an animal disease model. ZnO nanorods were grown to form nano-sized porous structures and coated with gold to facilitate size-selective biomarker detection. Raman spectra were acquired on a surface enhanced Raman substrate from the urine in a rat model of IC/BPS and analyzed using a statistical analysis method called principal component analysis (PCA). The nanorods grown after the ZnO seed deposition were 30 to 50 nm in diameter and 500 to 600 nm in length. A volume of gold corresponding to a thin film thickness of 100 nm was deposited on the grown nanorod structure. Raman spectroscopic signals were measured in the scattered region for nanometer biomarker detection to indicate IC/BPS. The Raman peaks for the control group and IC/BPS group are observed at 641, 683, 723, 873, 1002, 1030, and 1355 cm⁻¹, which corresponded to various bonding types and compounds. The PCA results are plotted in 2D and 3D. The Raman signals and statistical analyses obtained from the nano-sized biomarkers of intractable inflammatory diseases demonstrate the possibility of an early diagnosis.

Global analysis of protein homomerization in Saccharomyces cerevisiae

In vivo analyses of the occurrence, subcellular localization, and dynamics of protein–protein interactions (PPIs) are important issues in functional proteomic studies. The bimolecular fluorescence complementation (BiFC) assay has many advantages in that it provides a reliable way to detect PPIs in living cells with minimal perturbation of the structure and function of the target proteins. Previously, to facilitate the application of the BiFC assay to genome-wide analysis of PPIs, we generated a collection of yeast strains expressing full-length proteins tagged with the N-terminal fragment of Venus (VN), a yellow fluorescent protein variant, from their own native promoters. In the present study, we constructed a VC (the C-terminal fragment of Venus) fusion library consisting of 5671 MATα strains expressing C-terminally VC-tagged proteins (representing ∼91% of the yeast proteome). For genome-wide analysis of protein homomer formation, we mated each strain in the VC fusion library with its cognate strain in the VN fusion library and performed the BiFC assay. From this analysis, we identified 186 homomer candidates. We further investigated the functional relevance of the homomerization of Pln1, a yeast perilipin. Our data set provides a useful resource for understanding the physiological roles of protein homomerization. Furthermore, the VC fusion library together with the VN fusion library will provide a valuable platform to systematically analyze PPIs in the natural cellular context.

Integrative microendoscopic system combined with conventional microscope for live animal tissue imaging

Intravital optical imaging technology is essential for minimally invasive optical diagnosis and treatment in small animal disease models. High-resolution imaging requires high-resolution optical probes, and high-resolution optical imaging systems based on highly precise and advanced technologies and therefore, associated with high-system costs. Besides, in order to acquire small animal live images, special types of animal imaging setups are indispensable. In this paper, a microendoscopic system is designed as an add-on to existing conventional imaging microscopes, reducing the price of complete confocal endomicroscopic systems. The proposed attachable system can be configured for confocal microscopes from common manufacturers and this enables users to acquire live animal cellular images from a conventional system. It features a 4f optical plane relay system, a rotary stage for side-view endoscopic probes, and an endoscopic probe mount which swings between the horizontal and the vertical. The system could be widely useful for biological studies of animal physiology and disease models.

IL-32γ attenuates airway fibrosis by modulating the integrin-FAK signaling pathway in fibroblasts

Background

Fibrosis in severe asthma often leads to irreversible organ dysfunction. However, the mechanism that regulates fibrosis remains poorly understood. Interleukin (IL)-32 plays a role in several chronic inflammatory diseases, including severe asthma. In this study, we investigated whether IL-32 is involved in fibrosis progression in the lungs.

Methods

Murine models of chronic airway inflammation induced by ovalbumin and Aspergillus melleus protease and bleomycin-induced pulmonary fibrosis were employed. We evaluated the degree of tissue fibrosis after treatment with recombinant IL-32γ (rIL-32γ). Expression of fibronectin and α-smooth muscle actin (α-SMA) was examined and the transforming growth factor (TGF)-β-related signaling pathways was evaluated in activated human lung fibroblasts (MRC-5 cells) treated with rIL-32γ.

Results

rIL-32γ significantly attenuated collagen deposition and α-SMA production in both mouse models. rIL-32γ inhibited the production of fibronectin and α-SMA in MRC-5 cells stimulated with TGF-β. Additionally, rIL-32γ suppressed activation of the integrin-FAK-paxillin signaling axis but had no effect on the Smad and non-Smad signaling pathways. rIL-32γ localized outside of MRC-5 cells and inhibited the interaction between integrins and the extracellular matrix without directly binding to intracellular FAK and paxillin.

Conclusions

These results demonstrate that IL-32γ has anti-fibrotic effects and is a novel target for preventing fibrosis.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0863-3) contains supplementary material, which is available to authorized users.

Tracking the Fate of Porous Silicon Nanoparticles Delivering a Peptide Payload by Intrinsic Photoluminescence Lifetime

A nanoparticle system for systemic delivery of therapeutics is described, which incorporates a means of tracking the fate of the nanocarrier and its residual drug payload in vivo by photoluminescence (PL). Porous silicon nanoparticles (PSiNPs) containing the proapoptotic antimicrobial peptide payload, D [KLAKLAK]2 , are monitored by measurement of the intrinsic PL intensity and the PL lifetime of the nanoparticles. The PL lifetime of the PSiNPs is on the order of microseconds, substantially longer than the nanosecond lifetimes typically exhibited by conventional fluorescent tags or by autofluorescence from cells and tissues; thus, emission from the nanoparticles is readily discerned in the time-resolved PL spectrum. It is found that the luminescence lifetime of the PSiNP host decreases as the nanoparticle dissolves in phosphate-buffered saline solution (37 °C), and this correlates with the extent of release of the peptide payload. The time-resolved PL measurement allows tracking of the in vivo fate of PSiNPs injected (via tail vein) into mice. Clearance of the nanoparticles through the liver, kidneys, and lungs of the animals is observed. The luminescence lifetime of the PSiNPs decreases with increasing residence time in the mice, providing a measure of half-life for degradation of the drug nanocarriers.

Heterogeneous interaction network of yeast prions and remodeling factors detected in live cells

Budding yeast has dozens of prions, which are mutually dependent on each other for the de novo prion formation. In addition to the interactions among prions, transmissions of prions are strictly dependent on two chaperone systems: the Hsp104 and the Hsp70/Hsp40 (J-protein) systems, both of which cooperatively remodel the prion aggregates to ensure the multiplication of prion entities. Since it has been postulated that prions and the remodeling factors constitute complex networks in cells, a quantitative approach to describe the interactions in live cells would be required. Here, the researchers applied dual-color fluorescence cross-correlation spectroscopy to investigate the molecular network of interaction in single live cells. The findings demonstrate that yeast prions and remodeling factors constitute a network through heterogeneous protein-protein interactions.

Estrogen-related receptor gamma functions as a tumor suppressor in gastric cancer

The principle factors underlying gastric cancer (GC) development and outcomes are not well characterized resulting in a paucity of validated therapeutic targets. To identify potential molecular targets, we analyze gene expression data from GC patients and identify the nuclear receptor ESRRG as a candidate tumor suppressor. ESRRG expression is decreased in GC and is a predictor of a poor clinical outcome. Importantly, ESRRG suppresses GC cell growth and tumorigenesis. Gene expression profiling suggests that ESRRG antagonizes Wnt signaling via the suppression of TCF4/LEF1 binding to the CCND1 promoter. Indeed, ESRRG levels are found to be inversely correlated with Wnt signaling-associated genes in GC patients. Strikingly, the ESRRG agonist DY131 suppresses cancer growth and represses the expression of Wnt signaling genes. Our present findings thus demonstrate that ESRRG functions as a negative regulator of the Wnt signaling pathway in GC and is a potential therapeutic target for this cancer.

Protective role of endogenous plasmalogens against hepatic steatosis and steatohepatitis in mice

Free cholesterol (FC) accumulation in the liver is an important pathogenic mechanism of nonalcoholic steatohepatitis (NASH). Plasmalogens, key structural components of the cell membrane, act as endogenous antioxidants and are primarily synthesized in the liver. However, the role of hepatic plasmalogens in metabolic liver disease is unclear. In this study, we found that hepatic levels of docosahexaenoic acid (DHA)-containing plasmalogens, expression of glyceronephosphate O-acyltransferase (Gnpat; the rate-limiting enzyme in plasmalogen biosynthesis), and expression of Pparα were lower in mice with NASH caused by accumulation of FC in the liver. Cyclodextrin-induced depletion of FC transactivated Δ-6 desaturase by increasing sterol regulatory element-binding protein 2 expression in cultured hepatocytes. DHA, the major product of Δ-6 desaturase activation, activated GNPAT, thereby explaining the association between high hepatic FC and decreased Gnpat expression. Gnpat small interfering RNA treatment significantly decreased peroxisome proliferator-activated receptor α (Pparα) expression in cultured hepatocytes. In addition to GNPAT, DHA activated PPARα and increased expression of Pparα and its target genes, suggesting that DHA in the DHA-containing plasmalogens contributed to activation of PPARα. Accordingly, administration of the plasmalogen precursor, alkyl glycerol (AG), prevented hepatic steatosis and NASH through a PPARα-dependent increase in fatty acid oxidation. Gnpat^+/- mice were more susceptible to hepatic lipid accumulation and less responsive to the preventive effect of fluvastatin on NASH development, suggesting that endogenous plasmalogens prevent hepatic steatosis and NASH.

CONCLUSION

Increased hepatic FC in animals with NASH decreased plasmalogens, thereby sensitizing animals to hepatocyte injury and NASH. Our findings uncover a novel link between hepatic FC and plasmalogen homeostasis through GNPAT regulation. Further study of AG or other agents that increase hepatic plasmalogen levels may identify novel therapeutic strategies against NASH. (Hepatology 2017;66:416-431).

Light-Induced Fluorescence Modulation of Quantum Dot-Crystal Violet Conjugates: Stochastic Off-On-Off Cycles for Multicolor Patterning and Super-Resolution

Photoswitching or modulation of quantum dots (QDs) can be promising for many fields that include display, memory, and super-resolution imaging. However, such modulations have mostly relied on photomodulations of conjugated molecules in QD vicinity, which typically require high power of high energy photons at UV. We report a visible light-induced facile modulation route for QD-dye conjugates. QD crystal violets conjugates (QD-CVs) were prepared and the crystal violet (CV) molecules on QD quenched the fluorescence efficiently. The fluorescence of QD-CVs showed a single cycle of emission burst as they go through three stages of (i) initially quenched "off" to (ii) photoactivated "on" as the result of chemical change of CVs induced by photoelectrons from QD and (iii) back to photodarkened "off" by radical-associated reactions. Multicolor on-demand photopatterning was demonstrated using QD-CV solid films. QD-CVs were introduced into cells, and excitation with visible light yielded photomodulation from "off" to "on" and "off" by nearly ten fold. Individual photoluminescence dynamics of QD-CVs was investigated using fluorescence correlation spectroscopy and single QD emission analysis, which revealed temporally stochastic photoactivations and photodarkenings. Exploiting the stochastic fluorescence burst of QD-CVs, simultaneous multicolor super-resolution localizations were demonstrated.

Dynamic and coordinated single-molecular interactions at TM4SF5-enriched microdomains guide invasive behaviors in 2- and 3-dimensional environments

Membrane proteins sense extracellular cues and transduce intracellular signaling to coordinate directionality and speed during cellular migration. They are often localized to specific regions, as with lipid rafts or tetraspanin-enriched microdomains; however, the dynamic interactions of tetraspanins with diverse receptors within tetraspanin-enriched microdomains on cellular surfaces remain largely unexplored. Here, we investigated effects of tetraspan(in) TM4SF5 (transmembrane 4 L6 family member 5)-enriched microdomains (T₅ERMs) on the directionality of cell migration. Physical association of TM4SF5 with epidermal growth factor receptor (EGFR) and integrin α5 was visualized by live fluorescence cross-correlation spectroscopy and higher-resolution microscopy at the leading edge of migratory cells, presumably forming TM4SF5-enriched microdomains. Whereas TM4SF5 and EGFR colocalized at the migrating leading region more than at the rear, TM4SF5 and integrin α5 colocalized evenly throughout cells. Cholesterol depletion and disruption in TM4SF5 post-translational modifications, including N-glycosylation and palmitoylation, altered TM4SF5 interactions and cellular localization, which led to less cellular migration speed and directionality in 2- or 3-dimensional conditions. TM4SF5 controlled directional cell migration and invasion, and importantly, these TM4SF5 functions were dependent on cholesterol, TM4SF5 post-translational modifications, and EGFR and integrin α5 activity. Altogether, we showed that TM4SF5 dynamically interacted with EGFR and integrin α5 in migratory cells to control directionality and invasion.-Kim, H.-J., Kwon, S., Nam, S. H., Jung, J. W., Kang, M., Ryu, J., Kim, J. E., Cheong, J.-G., Cho, C. Y., Kim, S., Song, D.-G., Kim, Y.-N., Kim, T. Y., Jung, M.-K., Lee, K.-M., Pack, C.-G., Lee, J. W. Dynamic and coordinated single-molecular interactions at TM4SF5-enriched microdomains guide invasive behaviors in 2- and 3-dimensional environments.

In vivo stepwise immunomodulation using chitosan nanoparticles as a platform nanotechnology for cancer immunotherapy

Dentritic cell (DC)-based cancer immunotherapy faces challenges in both efficacy and practicality. However, DC-based vaccination requires multiple injections and elaborates ex vivo manipulation, which substantially limits their use. Therefore, we sought to develop a chitosan nanoparticle (CH-NP)-based platform for the next generation of vaccines to bypass the ex vivo manipulation and induce immune responses via active delivery of polyinosinic-polycytidylic acid sodium salt (poly I:C) to target Toll-like receptor 3 (TLR3) in endosomes. We developed CH-NPs encapsulating ovalbumin (OVA) as a model antigen and poly I:C as the adjuvant in an ionic complex. These CH-NPs showed increased in vivo intracellular delivery to the DCs in comparison with controls after injection into tumor-bearing mice, and promoted DC maturation, leading to emergence of antigen-specific cytotoxic CD8+ T cells. Finally, the CH-NPs showed significantly greater antitumor efficacy in EG.7 and TC-1 tumor-bearing mice compared to the control (p < 0.01). Taken together, these data show that the CH-NP platform can be used as an immune response modulatory vaccine for active cancer immunotherapy without ex vivo manipulation, thus resulting in increased anticancer efficacy.

A novel sphingomyelin/cholesterol domain-specific probe reveals the dynamics of the membrane domains during virus release and in Niemann-Pick type C

We identified a novel, nontoxic mushroom protein that specifically binds to a complex of sphingomyelin (SM), a major sphingolipid in mammalian cells, and cholesterol (Chol). The purified protein, termed nakanori, labeled cell surface domains in an SM- and Chol-dependent manner and decorated specific lipid domains that colocalized with inner leaflet small GTPase H-Ras, but not K-Ras. The use of nakanori as a lipid-domain-specific probe revealed altered distribution and dynamics of SM/Chol on the cell surface of Niemann-Pick type C fibroblasts, possibly explaining some of the disease phenotype. In addition, that nakanori treatment of epithelial cells after influenza virus infection potently inhibited virus release demonstrates the therapeutic value of targeting specific lipid domains for anti-viral treatment.-Makino, A., Abe, M., Ishitsuka, R., Murate, M., Kishimoto, T., Sakai, S., Hullin-Matsuda, F., Shimada, Y., Inaba, T., Miyatake, H., Tanaka, H., Kurahashi, A., Pack, C.-G., Kasai, R. S., Kubo, S., Schieber, N. L., Dohmae, N., Tochio, N., Hagiwara, K., Sasaki, Y., Aida, Y., Fujimori, F., Kigawa, T., Nishibori, K., Parton, R. G., Kusumi, A., Sako, Y., Anderluh, G., Yamashita, M., Kobayashi, T., Greimel, P., Kobayashi, T. A novel sphingomyelin/cholesterol domain-specific probe reveals the dynamics of the membrane domains during virus release and in Niemann-Pick type C.

Analyses of the Dynamic Properties of Nuclear Lamins by Fluorescence Recovery After Photobleaching (FRAP) and Fluorescence Correlation Spectroscopy (FCS)

The major structural components of the nuclear lamina are the A- and B-type nuclear lamin proteins which are also present in the nucleoplasm. Studies of molecular movements of the lamins in both the lamina and nucleoplasm of living cell nuclei have provided insights into their roles in maintaining nuclear architecture. In this chapter, we present protocols for quantitatively measuring the mobilities of lamin proteins by fluorescence recovery after photobleaching (FRAP) and fluorescence correlation spectroscopy (FCS) in mammalian cell nuclei.

Peptide sequences converting polyglutamine into a prion in yeast

Amyloids are ordered protein aggregates composed of cross-β sheet structures. Amyloids include prions, defined as infectious proteins, which are responsible for mammalian transmissible spongiform encephalopathies, and fungal prions. Although the conventional view is that typical amyloids are associated with nontransmissible mammalian neurodegenerative diseases such as Alzheimer's disease, increasing evidence suggests that the boundary between transmissible and nontransmissible amyloids is ambiguous. To clarify the mechanism underlying the difference in transmissibility, we investigated the dynamics and the properties of polyglutamine (polyQ) amyloids in yeast cells, in which the polyQ aggregates are not transmissible but can be converted into transmissible amyloids. We found that polyQ had an increased tendency to form aggregates compared to the yeast prion Sup35. In addition, we screened dozens of peptides that converted the nontransmissible polyQ to transmissible aggregates when they flanked the polyQ stretch, and also investigated their cellular dynamics aiming to understand the mechanism of transmission.

Dynamic and unique nucleolar microenvironment revealed by fluorescence correlation spectroscopy

Organization and functions of the nucleolus is maintained by mobilities and interactions of nucleolar factors. Because the nucleolus is a densely packed structure, molecular crowding effects determined by the molecular concentrations and mobilities in the nucleolus should also be important for regulating nucleolar organization and functions. However, such molecular property of nucleolar organization is not fully understood. To understand the biophysical property of nucleolar organization, the diffusional behaviors of inert green fluorescent protein (GFP) oligomers with or without nuclear localization signals (NLSs) were analyzed under various conditions by fluorescence correlation spectroscopy. Our result demonstrates that the mobility of GFPs inside the nucleolus and the nucleoplasm can be represented by single free diffusion under normal conditions, even though the mobility in the nucleolus is considerably slower than that in the chromatin region. Moreover, the free diffusion of GFPs is found to be significantly size- and NLS-dependent only in the nucleolus. Interestingly, the mobility in the nucleolus is highly sensitive to ATP depletion, as well as actinomycin D (ActD) treatment. In contrast, the ultra-structure of the nucleolus was not significantly changed by ATP depletion but was changed by ActD treatment. These results suggest that the nucleolus behaves similarly to an open aqueous-phase medium with an increased molecular crowding effect that depends on both energy and transcription.

Interphase phosphorylation of lamin A

Nuclear lamins form the major structural elements that comprise the nuclear lamina. Loss of nuclear structural integrity has been implicated as a key factor in the lamin A/C gene mutations that cause laminopathies, whereas the normal regulation of lamin A assembly and organization in interphase cells is still undefined. We assumed phosphorylation to be a major determinant, identifying 20 prime interphase phosphorylation sites, of which eight were high-turnover sites. We examined the roles of these latter sites by site-directed mutagenesis, followed by detailed microscopic analysis - including fluorescence recovery after photobleaching, fluorescence correlation spectroscopy and nuclear extraction techniques. The results reveal three phosphorylation regions, each with dominant sites, together controlling lamin A structure and dynamics. Interestingly, two of these interphase sites are hyper-phosphorylated in mitotic cells and one of these sites is within the sequence that is missing in progerin of the Hutchinson-Gilford progeria syndrome. We present a model where different phosphorylation combinations yield markedly different effects on the assembly, subunit turnover and the mobility of lamin A between, and within, the lamina, the nucleoplasm and the cytoplasm of interphase cells.

Quantitative live-cell imaging reveals spatio-temporal dynamics and cytoplasmic assembly of the 26S proteasome

The 26S proteasome is a 2.5-MDa multisubunit protease complex that degrades polyubiquitylated proteins. Although its functions and structure have been extensively characterized, little is known about its dynamics in living cells. Here, we investigate the absolute concentration, spatio-temporal dynamics and complex formation of the proteasome in living cells using fluorescence correlation spectroscopy. We find that the 26S proteasome complex is highly mobile, and that almost all proteasome subunits throughout the cell are stably incorporated into 26S proteasomes. The interaction between 19S and 20S particles is stable even in an importin-α mutant, suggesting that the 26S proteasome is assembled in the cytoplasm. Furthermore, a genetically stabilized 26S proteasome mutant is able to enter the nucleus. These results suggest that the 26S proteasome completes its assembly process in the cytoplasm and translocates into the nucleus through the nuclear pore complex as a holoenzyme.

Viscosity and drag force involved in organelle transport: investigation of the fluctuation dissipation theorem

We observed the motion of an organelle transported by motor proteins in cells using fluorescence microscopy. Particularly, among organelles, the mitochondria in PC12 cells were studied. A mitochondrion was dragged at a constant speed for several seconds without pausing. We investigated the fluctuation dissipation theorem for this constant drag motion by comparing it with the motion of Brownian beads that were incorporated into the cells by an electroporation method. We estimated the viscosity value inside cells from the diffusion coefficients of the beads. Then the viscosity value obtained by using the beads was found to be slightly lower than that obtained from the diffusion coefficient for the organelle motion via the Einstein relation. This discrepancy indicates the violation of the Einstein relation for the organelle motion.

Photosystem II antenna phosphorylation-dependent protein diffusion determined by fluorescence correlation spectroscopy

Flexibility of chloroplast thylakoid membrane proteins is essential for plant fitness and survival under fluctuating light environments. Phosphorylation of light-harvesting antenna complex II (LHCII) is known to induce dynamic protein reorganization that fine-tunes the rate of energy conversion in each photosystem. However, molecular details of how LHCII phosphorylation causes light energy redistribution throughout thylakoid membranes still remain unclear. By using fluorescence correlation spectroscopy, we here determined the LHCII phosphorylation-dependent protein diffusion in thylakoid membranes isolated from the green alga Chlamydomonas reinhardtii. As compared to the LHCII dephosphorylation-induced condition, the diffusion coefficient of LHCII increased nearly twofold under the LHCII phosphorylation-induced condition. We also verified the results by using the LHCII phosphorylation-deficient mutant. Our observation suggests that LHCII phosphorylation-dependent protein reorganization occurs along with the changes in the rate of protein diffusion, which would have an important role in mediating light energy redistribution throughout thylakoid membranes.

Heat shock instructs hESCs to exit from the self-renewal program through negative regulation of OCT4 by SAPK/JNK and HSF1 pathway

Environmental factors affect self-renewal of stem cells by modulating the components of self-renewal networks. Heat shock, an environmental factor, induces heat shock factors (HSFs), which up-regulate stress response-related genes. However, the link of heat shock to self-renewal of stem cells has not been elucidated yet. Here, we present the direct link of heat shock to a core stem cell regulator, OCT4, in the self-renewal network through SAPK/JNK and HSF1 pathway. We first showed that heat shock initiated differentiation of human embryonic stem cells (hESCs). Gene expression analysis revealed that heat shock increased the expression of many genes involved in cellular processes related to differentiation of stem cells. We then examined the effects of HSFs induced by heat shock on core self-renewal factors. Among HSFs, heat shock induced mainly HSF1 in hESCs. The HSF1 repressed the expression of OCT4, leading to the differentiation of hESCs and the above differentiation-related gene expression change. We further examined the effects of the upstream MAP (mitogen-activated protein) kinases of HSF1 on the repression of OCT4 expression by HSF1. Among the MAP kinases, SAPK/JNK controlled predominantly the repression of the OCT4 expression by HSF1. The direct link of heat shock to the core self-renewal regulator through SAPK/JNK and HSF1 provides a fundamental basis for understanding the effect of heat and other stresses involving activation of HSF1 on the self-renewal program and further controlling differentiation of hESCs in a broad spectrum of stem cell applications using these stresses.