Polarity Complex Research Articles

Color image watermarking using vector SNCM-HMT

An image watermarking scheme is typically evaluated using three main conflicting characteristics: imperceptibility, robustness, and capacity. Developing a good image watermarking method is challenging because it requires a trade-off between these three basic characteristics. In this paper, we proposed a statistical color image watermarking based on robust discrete nonseparable Shearlet transform (DNST)-fast quaternion generic polar complex exponential transform (FQGPCET) magnitude and vector skew-normal-Cauchy mixtures (SNCM)-hidden Markov tree (HMT). The proposed watermarking system consists of two main parts: watermark inserting and watermark extraction. In watermark inserting, we first perform DNST on R, G, and B components of color host image, respectively. We then compute block FQGPCET of DNST domain color components, and embed watermark signal in DNST-FQGPCET magnitudes using multiplicative approach. In watermark extraction, we first analyze the robustness and statistical characteristics of local DNST-FQGPCET magnitudes of color image. We then observe that, vector SNCM-HMT model can capture accurately the marginal distribution and multiple strong dependencies of local DNST-FQGPCET magnitudes. Meanwhile, vector SNCM-HMT parameters can be computed effectively using variational expectation–maximization (VEM) parameter estimation. Motivated by our modeling results, we finally develop a new statistical color image watermark decoder based on vector SNCM-HMT and maximum likelihood (ML) decision rule. Experimental results on extensive test images demonstrate that the proposed statistical color image watermarking provides a performance better than that of most of the state-of-the-art statistical methods and some deep learning approaches recently proposed in the literature.

The Scribble-SGEF-Dlg1 complex regulates E-cadherin and ZO-1 stability, turnover and transcription in epithelial cells.

SGEF (also known as ARHGEF26), a RhoG specific GEF, can form a ternary complex with the Scribble polarity complex proteins Scribble and Dlg1, which regulates the formation and maintenance of adherens junctions and barrier function of epithelial cells. Notably, silencing SGEF results in a dramatic downregulation of both E-cadherin and ZO-1 (also known as TJP1) protein levels. However, the molecular mechanisms involved in the regulation of this pathway are not known. Here, we describe a novel signaling pathway governed by the Scribble-SGEF-Dlg1 complex. Our results show that the three members of the ternary complex are required to maintain the stability of the apical junctions, ZO-1 protein levels and tight junction (TJ) permeability. In contrast, only SGEF is necessary to regulate E-cadherin levels. The absence of SGEF destabilizes the E-cadherin-catenin complex at the membrane, triggering a positive feedback loop that exacerbates the phenotype through the repression of E-cadherin transcription in a process that involves the internalization of E-cadherin by endocytosis, β-catenin signaling and the transcriptional repressor Slug (also known as SNAI2).

Collagen prolyl 4-hydroxylase subunit α member-induced head and neck squamous cell carcinoma aggressiveness is antagonized by LLGL2 via reduced expression of occludin.

There are three isoforms of human collagen prolyl 4-hydroxylases (C-P4Hs), each of which has been reported to play an important role in regulating the progression of a variety of human cancers. By analyzing TGCA datasets on human head and neck squamous cell carcinoma (HNSC), we find that a higher expression of all three C-P4HAs (the α subunit of C-P4Hs) is a superior prognostic indicator than a higher expression of two or a single C-P4HA. Unexpectedly, some patients with higher levels of three C-P4HAs survive longer than patients whose tumors have lower expression of C-P4HAs. Therefore, there may be molecule(s) that can negate the deleterious effects of overexpressing C-P4HAs during cancer progression. By constructing a functional protein interaction network of C-P4HAs and analyzing molecules whose expressions are correlated significantly with that of C-P4HAs, we identify scribble cell polarity complex component 2 (LLGL2) as a factor that antagonizes the effects of overexpressed C-P4HAs on HNSC. Silencing of LLGL2 in the human oral squamous cell line Cal-27 upregulates the expression of occludin and increases cancer cell invasion and migration. In contrast, knocking down C-P4HA alone inhibits cell migration and invasion. Furthermore, simultaneously downregulating three C-P4HAs has more pronounced effects on inhibiting cell migration and invasion. Accordingly, high LLGL2 expression is also a marker indicating improved prognosis in patients with HNSC. These results suggest that the interplay between LLGL2 and C-P4HAs may be targeted to mitigate HNSC tumorigenesis and progression.

Par polarity complex member Par-3 promotes cytotrophoblast fusion via Hippo signaling

Par polarity complex member Par-3 promotes cytotrophoblast fusion via Hippo signaling

Loss of symmetric cell division of apical neural progenitors drives DENND5A-related developmental and epileptic encephalopathy

Developmental and epileptic encephalopathies (DEEs) feature altered brain development, developmental delay and seizures, with seizures exacerbating developmental delay. Here we identify a cohort with biallelic variants in DENND5A, encoding a membrane trafficking protein, and develop animal models with phenotypes like the human syndrome. We demonstrate that DENND5A interacts with Pals1/MUPP1, components of the Crumbs apical polarity complex required for symmetrical division of neural progenitor cells. Human induced pluripotent stem cells lacking DENND5A fail to undergo symmetric cell division with an inherent propensity to differentiate into neurons. These phenotypes result from misalignment of the mitotic spindle in apical neural progenitors. Cells lacking DENND5A orient away from the proliferative apical domain surrounding the ventricles, biasing daughter cells towards a more fate-committed state, ultimately shortening the period of neurogenesis. This study provides a mechanism for DENND5A-related DEE that may be generalizable to other developmental conditions and provides variant-specific clinical information for physicians and families.

Mesenchymal Vangl1 and Vangl2 facilitate airway elongation and widening independently of the planar cell polarity complex.

Adult mammalian lungs exhibit a fractal pattern, as each successive generation of airways is a fraction of the size of the parental branch. Achieving this structure likely requires precise control of airway length and diameter, as the embryonic airways initially lack the fractal scaling observed in the adult. In monolayers and tubes, directional growth can be regulated by the planar cell polarity (PCP) complex. Here, we characterized the roles of PCP complex components in airway initiation, elongation and widening during branching morphogenesis of the lung. Using tissue-specific knockout mice, we surprisingly found that branching morphogenesis proceeds independently of PCP complex function in the lung epithelium. Instead, we found a previously unreported Celsr1-independent role for the PCP complex components Vangl1 and Vangl2 in the pulmonary mesenchyme, where they are required for branch initiation, elongation and widening. Our data thus reveal an explicit function for Vangl1 and Vangl2 that is independent of the core PCP complex, suggesting a functional diversification of PCP complex components in vertebrate development. These data also reveal an essential role for the embryonic mesenchyme in generating the fractal structure of airways in the mature lung.

Topological Analysis of Image Reconstruction Based on Polar Complex Exponential Transform

Image moments are an important tool used for image reconstruction. An image can be represented in terms of image moments, which is known as image reconstruction from its moments. To construct an image from the moments, a question often arises that how many moments are required for the reconstruction of image. Theoretically, many image moments may be required for accurately reconstructing an image. However, since image moment construction can be computationally challenging, often in practice only a finite number of moments are used for the image reconstruction. The difference in reconstructed and original image for many numbers of images can lead to a satisfying answer. However, accurate reconstruction may not often be possible, and we are often relying on other approaches to find similarity between the original image and reconstructed image. We used a similarity based on a topological data analysis tool known as the persistence diagram, determining the bottleneck distance between the original and the reconstructed image as the measure of similarity. Our investigation was conducted on the common images utilized in image processing tasks. The findings indicate that there is no direct correlation between the number of moments and the quality of image reconstruction. It is necessary to choose an appropriate number of moments, which may be very small, instead of calculating a high number of image moments.

DLG1 functions upstream of SDCCAG3 and IFT20 to control ciliary targeting of polycystin-2

Polarized vesicular trafficking directs specific receptors and ion channels to cilia, but the underlying mechanisms are poorly understood. Here we describe a role for DLG1, a core component of the Scribble polarity complex, in regulating ciliary protein trafficking in kidney epithelial cells. Conditional knockout of Dlg1 in mouse kidney causes ciliary elongation and cystogenesis, and cell-based proximity labeling proteomics and fluorescence microscopy show alterations in the ciliary proteome upon loss of DLG1. Specifically, the retromer-associated protein SDCCAG3, IFT20, and polycystin-2 (PC2) are reduced in the cilia of DLG1-deficient cells compared to control cells. This phenotype is recapitulated in vivo and rescuable by re-expression of wild-type DLG1, but not a Congenital Anomalies of the Kidney and Urinary Tract (CAKUT)-associated DLG1 variant, p.T489R. Finally, biochemical approaches and Alpha Fold modelling suggest that SDCCAG3 and IFT20 form a complex that associates, at least indirectly, with DLG1. Our work identifies a key role for DLG1 in regulating ciliary protein composition and suggests that ciliary dysfunction of the p.T489R DLG1 variant may contribute to CAKUT.

A computational analysis of the role of integrins and Rho-GTPases in the emergence and disruption of apical-basal polarization in renal epithelial cells.

Apical-basal polarization in renal epithelial cells is crucial to renal function and an important trigger for tubule formation in kidney development. Loss of polarity can induce epithelial-to-mesenchymal transition (EMT), which can lead to kidney pathologies. Understanding the relative and combined roles of the involved proteins and their interactions that govern epithelial polarity may provide insights for controlling the process of polarization via chemical or mechanical manipulations in an in vitro or in vivo setting. Here, we developed a computational framework that integrates several known interactions between integrins, Rho-GTPases Rho, Rac and Cdc42, and polarity complexes Par and Scribble, to study their mutual roles in the emergence of polarization. The modeled protein interactions were shown to induce the emergence of polarized distributions of Rho-GTPases, which in turn led to the accumulation of apical and basal polarity complexes Par and Scribble at their respective poles, effectively recapitulating polarization. Our multiparametric sensitivity analysis suggested that polarization depends foremost on the mutual inhibition between Rac and Rho. Next, we used the computational framework to investigate the role of integrins and GTPases in the generation and disruption of polarization. We found that a minimum concentration of integrins is required to catalyze the process of polarization. Furthermore, loss of polarization was found to be only inducible via complete degradation of the Rho-GTPases Rho and Cdc42, suggesting that polarization is fairly stable once it is established. Comparison of our computational predictions against data from in vitro experiments in which we induced EMT in renal epithelial cells while quantifying the relative Rho-GTPase levels, displayed that EMT coincides with a large reduction in the Rho-GTPase Rho. Collectively, these results demonstrate the essential roles of integrins and Rho-GTPases in the establishment and disruption of apical-basal polarity and thereby provide handles for the in vitro or in vivo regulation of polarity.

Abstract 372: Cell polarity proteins as novel regulators of macropinocytosis in pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is considered one of the deadliest cancers. This is likely because it is detected at a very late stage and the therapeutic approaches that have been used for its treatment have proven to be quite ineffective. Therefore, new therapeutic strategies are needed for a better prognosis in patients suffering of pancreatic cancer. PDAC cells often rewire their metabolism to survive and progress. This metabolic rewiring permits the acquisition of nutrients by the cells when these are exposed to a poor nutrient microenvironment. One of the most used processes in nutrient stress conditions is the “cell-drinking” pathway macropinocytosis, an endocytic pathway that cancer cells exploit to support cancer metabolism in such unfavorable conditions. Macropinocytosis inhibition has shown to suppress PDAC growth in mice and thus, it has become a promising therapeutic target for PDAC treatment. Here, we describe that atypical Protein Kinase C (aPKC) isoforms Protein Kinase C zeta (PKCζ) and Protein Kinase C iota (PKCι) regulate PDAC macropinocytosis in the context of glutamine stress. Genetic depletion and pharmacological inhibition of aPKC impair macropinocytosis promotion in PDAC cells exposed to a glutamine-deprived environment and in cells treated with DON, a glutamine analog that blocks glutamine metabolism. In epithelial cells, aPKCs are known to regulate the establishment of cell polarity in association with the scaffold proteins Par3 and Par6, constituting the cell polarity complex, which controls the function of different targets such as Par1 kinases. Loss of Par3, Par6 and Par-1a affects glutamine stress associated macropinocytosis in a similar extent than aPKC depletion, presenting a novel role of the cell polarity protein network in the modulation of macropinocytic uptake. Citation Format: Guillem Lambies Barjau, Szu-Wei Lee, Cosimo Commisso. Cell polarity proteins as novel regulators of macropinocytosis in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 372.

Spatially resolved proteomics of the Arabidopsis stomatal lineage identifies polarity complexes for cell divisions and stomatal pores

Cell polarity is used to guide asymmetric divisions and create morphologically diverse cells. We find that two oppositely oriented cortical polarity domains present during the asymmetric divisions in the Arabidopsis stomatal lineage are reconfigured into polar domains marking ventral (pore-forming) and outward-facing domains of maturing stomatal guard cells. Proteins that define these opposing polarity domains were used as baits in miniTurboID-based proximity labeling. Among differentially enriched proteins, we find kinases, putative microtubule-interacting proteins, and polar SOSEKIs with their effector ANGUSTIFOLIA. Using AI-facilitated protein structure prediction models, we identify potential protein-protein interaction interfaces among them. Functional and localization analyses of the polarity protein OPL2 and its putative interaction partners suggest a positive interaction with mitotic microtubules and a role in cytokinesis. This combination of proteomics and structural modeling with live-cell imaging provides insights into how polarity is rewired in different cell types and cell-cycle stages.

Measurement of Kerr rotation and ellipticity in magnetic thin films by MOKE magnetometry

When polarized light is incident on a magnetic material, the magneto-optical Kerr effect (MOKE) rotates the polarization and induces ellipticity in the reflected light, which allows the magnetization direction to be probed optically. The Kerr rotation and ellipticity determine the magnitude of the effect and are usually measured using dedicated ellipsometers. Here, we demonstrate a simple method for extracting Kerr rotation and ellipticity in magnetic thin films using a conventional MOKE magnetometer consisting of two polarizers and a quarter waveplate. Using this technique, we report the longitudinal Kerr angle of BiYIG, GdCo, and TbCo. We additionally observe a linear decrease in polar complex Kerr angle magnitude in 3 nm GdCo films as the atomic fraction of Gd is increased.

Cell polarization in ischemic stroke: molecular mechanisms and advances.

Ischemic stroke is a cerebrovascular disease associated with high mortality and disability rates. Since the inflammation and immune response play a central role in driving ischemic damage, it becomes essential to modulate excessive inflammatory reactions to promote cell survival and facilitate tissue repair around the injury site. Various cell types are involved in the inflammatory response, including microglia, astrocytes, and neutrophils, each exhibiting distinct phenotypic profiles upon stimulation. They display either proinflammatory or anti-inflammatory states, a phenomenon known as 'cell polarization.' There are two cell polarization therapy strategies. The first involves inducing cells into a neuroprotective phenotype in vitro, then reintroducing them autologously. The second approach utilizes small molecular substances to directly affect cells in vivo. In this review, we elucidate the polarization dynamics of the three reactive cell populations (microglia, astrocytes, and neutrophils) in the context of ischemic stroke, and provide a comprehensive summary of the molecular mechanisms involved in their phenotypic switching. By unraveling the complexity of cell polarization, we hope to offer insights for future research on neuroinflammation and novel therapeutic strategies for ischemic stroke.

Polar Organic Charge-Transfer Complex of the Asymmetrical Component for Flexible Piezoelectric Energy Harvesting and Self-Powered Wearable Sensors.

Organic piezomaterials have attracted much attention because of their easy processing, lightweight, and mechanic flexibility properties. Developing new smart organic piezomaterials is highly required for new-generation electronic applications. Here, we found a novel organic piezomaterial of organic charge-transfer complex (CTC) consisting of dibenzcarbazole analogue (DBCz) and tetracyanoquinodimethane (TCNQ) in the molecular-level heterojunction stacking mode. The DBCz-TCNQ complex exhibited ferroelectric properties (the saturated polarization of ∼1.23 μC/cm2) at room temperature with a low coercive field. The noncentrosymmetric alignment (Pc space group) led to a spontaneous polarization of this architecture and thus was the origin of the piezoelectric behavior. Lateral piezoelectric nanogenerators (PENGs) based on the thermal evaporated CTC thin-film exhibited significant energy conversion behavior under mechanical agitation with a calculated piezoelectric coefficient (d31) of ∼33 pC/N. Furthermore, such a binary CTC thin-film constructed single-electrode PENG could show steady-state sensing performance to external stimuli as this flexible wearable device precisely detected physiological signals (e.g., finger bending, blink movement, carotid artery, etc.) with a self-powered supply. This work provides that the polar CTCs can act as efficient piezomaterials for flexible energy harvesting, conversion, and wearable sensing devices with a self-powered supply, enabling great potential in healthcare, motion detection, human-machine interfaces, etc.

Functional oligo- and polypeptide assemblies for photochemical, optical and electronic applications.

The primary and secondary structures of peptides are useful as scaffolds to sequentially arrange functional groups of molecules. In this review, we review self-assembled functional peptides, whereby peptides with appropriate amino acid sequences can assemble using functional groups on their side chains. First, we apply our design strategies for the synthesis of peptide-based materials with sequenced side chains with polar moieties, organic dyes and metal complexes. The synthetic oligopeptides thus obtained exhibit inherent photoinduced charge separation and electrochemical redox activities, as well as responses to bio-sequences. Next, catalytic and photocatalytic oxidation reduction reactions and hydrogen evolution reactions are shown by utilizing the peptides with separated functionalities on both sides of β-sheets by hybridizing with electro- and photoactive graphene oxide and metal nanoparticles. Finally, the self-assembled natural proteins that form micrometre-scale spherical geometry and fibres are utilized for optical and electronic applications. The silk fibroin forms well-defined microspheres with smooth surface morphology, leading to properties suitable for use in optical resonators, which can sense external humidity because of the hygroscopic nature of silk fibroin. Dragline silk fibres can act as optical waveguides that can perform intermediate natural polymer-based optical logic operations. These functional peptides are utilizable for various applications in catalysis, optics and electronics.

Locally optimum watermark decoder based on fast quaternion generic polar complex exponential transform

Locally optimum watermark decoder based on fast quaternion generic polar complex exponential transform

Blind image watermark decoder in NSST-FPCET domain using Weibull Mixtures-HMT

Balancing imperceptibility, robustness, and data payload is a key topic in digital watermarking technology. Many contributions point to statistical modeling as an effective solution to this problem. On the basis of this, in this paper, we devise a hybrid domain image watermark decoder based on Weibull mixtures based hidden Markov tree (Weibull Mixtures-HMT) model. In the embedding phase, Otsu-Canny edge detection method is used to map the positions of high entropy blocks to the target subband obtained by non-subsampled shearlet transform (NSST), and fast polar complex exponential transform (FPCET) is computed in the target blocks to obtain the NSST-FPCET domain. The watermark signals are embedded into NSST-FPCET magnitudes by a linear method. In the extraction phase, NSST-FPCET magnitude coefficients are modeled by Weibull Mixtures-HMT model, which describes the distribution characteristics as well as the dependencies of NSST-FPCET magnitudes. The efficient variance reduced stochastic expectation maximization method is employed for estimating the parameters of Weibull Mixtures-HMT model. A statistical image watermark decoder in NSST-FPCET domain is finally achieved by the maximum likelihood decision. Massive experiments are performed so as to confirm the superiority of the designed scheme in trade-off among the data payload, imperceptibility, and robustness.

Supramolecular gelators enabling chiral organogels for naked-eye enantiodifferentiation with wide accessibility and applicability

Techniques to acquire chiral information from molecules are essential for deciphering important biological processes and improving the performance of industrial chiral materials. Herein, we report novel supramolecular gelators that enable widely accessible chiral supramolecular organogels for simple naked-eye enantiodifferentiation of specific enantiomers (left- or right-handedness) for wide-range substances. The supramolecular gelators featuring multiple hydrogen-bonding sites and large π-π conjugated groups are produced by complexing commercially available chiral tartaric acids and achiral 1-naphthylmethylamine. The highly polar and insoluble acid-amine complexes drive the aggregation of the supramolecular gelators, which further form chiral nanofibers due to chirality transfer from tartaric acid to the supramolecular nanofibers through multiple hydrogen-bonding between the hydroxyl groups of chiral tartaric acids and π-π stacking between 1-naphthylmethylamine molecules. At high concentrations, physical crosslinking of the chiral nanofibers creates a chiral gel structure that facilitates interactions between its chirally and non-covalently associated components and enantiomers, making the gel system particularly sensitive to specific types of enantiomers. Consequently, sensitive naked-eye detection of specific enantiomers of diverse substances is achieved via observing “gel-to-micelle” transitions, which occurs when the enantiomers generate complexes that disrupt chirality transfer in the co-assembly and destroy the hierarchical structures.

MPDZ is associated with immune infiltration and regulates migration and invasion by switching YAP1 phosphorylation in colorectal cancer

BackgroundMultiple PDZ Domain Crumbs Cell Polarity Complex Component (MPDZ) is involved in a few human cancers. However, the features and potential mechanisms of MPDZ in progression of colorectal cancer (CRC) remains unknown. MethodsThe prognostic role of MPDZ in CRC was determined by Kaplan-Meier and univariate regression analysis. Enrichment analysis was performed to characterize crucial pathways of MPDZ. Immune infiltration and immunotherapeutic outcome were further evaluated. CCK8, EDU, transwell, and wound healing assay were used to assess the influence of MPDZ on pernicious performance of CRC cells. CD8+ T cells and CRC cells were co-cultured to explore the effect of MPDZ on the tumor microenvironment. qRT–PCR, western blot, immunoprecipitation (IP), and methylated RNA immunoprecipitation (me-RIP) were implemented in seeking for the potential mechanisms of MPDZ in CRC. ResultsCRC patients with elevated MPDZ expression suffered from significantly worse prognosis. Enrichment analysis revealed that MPDZ involved in pathways related to metastasis and cell cycle in CRC. In addition, MPDZ expression were related to several immunoinhibitors and had the ability to predict immunotherapy response. Finally, in vitro assays demonstrated that MPDZ knockdown inhibited migration, invasion and immune evasion of CRC cells. Mechanistically, MPDZ knockdown enhanced YAP1 phosphorylation by increased LATS1 expression. Moreover, m6A-MPDZ mRNA may be recognized and degraded by m6A recognition protein YTHDF2. ConclusionsMPDZ was critical for CRC development and could be a promising candidate for the treatment of CRC patients.

PATJ inhibits histone deacetylase 7 to control tight junction formation and cell polarity

The conserved multiple PDZ-domain containing protein PATJ stabilizes the Crumbs-Pals1 complex to regulate apical-basal polarity and tight junction formation in epithelial cells. However, the molecular mechanism of PATJ’s function in these processes is still unclear. In this study, we demonstrate that knockout of PATJ in epithelial cells results in tight junction defects as well as in a disturbed apical-basal polarity and impaired lumen formation in three-dimensional cyst assays. Mechanistically, we found PATJ to associate with and inhibit histone deacetylase 7 (HDAC7). Inhibition or downregulation of HDAC7 restores polarity and lumen formation. Gene expression analysis of PATJ-deficient cells revealed an impaired expression of genes involved in cell junction assembly and membrane organization, which is rescued by the downregulation of HDAC7. Notably, the function of PATJ regulating HDAC7-dependent cilia formation does not depend on its canonical interaction partner, Pals1, indicating a new role of PATJ, which is distinct from its function in the Crumbs complex. By contrast, polarity and lumen phenotypes observed in Pals1- and PATJ-deficient epithelial cells can be rescued by inhibition of HDAC7, suggesting that the main function of this polarity complex in this process is to modulate the transcriptional profile of epithelial cells by inhibiting HDAC7.