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Physical Review Letters Mar 2023The combination of conventional polarization optical elements, such as linear polarizers and waveplates, is widely adopted to tailor light's state of polarization (SOP)....
The combination of conventional polarization optical elements, such as linear polarizers and waveplates, is widely adopted to tailor light's state of polarization (SOP). Meanwhile, less attention has been given to the manipulation of light's degree of polarization (DOP). Here, we propose metasurface-based polarizers that can filter unpolarized incident light to light with any prescribed SOP and DOP, corresponding to arbitrary points located both at the surface and within the solid Poincaré sphere. The Jones matrix elements of the metasurface are inverse-designed via the adjoint method. As prototypes, we experimentally demonstrated metasurface-based polarizers in near-infrared frequencies that can convert unpolarized light into linear, elliptical, or circular polarizations with varying DOPs of 1, 0.7, and 0.4, respectively. Our Letter unlocks a new degree of freedom for metasurface polarization optics and may break new ground for a variety of DOP-related applications, such as polarization calibration and quantum state tomography.
PubMed: 37027878
DOI: 10.1103/PhysRevLett.130.123801 -
Current Biology : CB Jun 2019How do cells polarize at the correct time and in response to the correct cues? In the C. elegans zygote, the timing and geometry of polarization rely on a single...
How do cells polarize at the correct time and in response to the correct cues? In the C. elegans zygote, the timing and geometry of polarization rely on a single dominant cue-the sperm centrosome-that matures at the end of meiosis and specifies the nascent posterior. Polarization requires that the conserved PAR proteins, which specify polarity in the zygote, be poised to respond to the centrosome. Yet, how and when PAR proteins achieve this unpolarized, but responsive, state is unknown. We show that oocyte maturation initiates a fertilization-independent PAR activation program. PAR proteins are initially not competent to polarize but gradually acquire this ability following oocyte maturation. Surprisingly, this program allows symmetry breaking even in unfertilized oocytes lacking centrosomes. Thus, if PAR proteins can respond to multiple polarizing cues, how is specificity for the centrosome achieved? Specificity is enforced by Polo-like and Aurora kinases (PLK-1 and AIR-1 in C. elegans), which impose a delay in the activation of the PAR network so that it coincides with maturation of the centrosome cue. This delay suppresses polarization by non-centrosomal cues, which can otherwise trigger premature polarization and multiple or reversed polarity domains. Taken together, these findings identify a regulatory program that enforces proper polarization by synchronizing PAR network activation with cell cycle progression, thereby ensuring that PAR proteins respond specifically to the correct cue. Temporal control of polarity network activity is likely to be a common strategy to ensure robust, dynamic, and specific polarization in response to developmentally deployed cues.
Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cues; Oocytes; Orientation, Spatial; Protein Serine-Threonine Kinases
PubMed: 31155349
DOI: 10.1016/j.cub.2019.04.058 -
Traffic (Copenhagen, Denmark) Apr 2015Exosomes are extracellular vesicles that transport different molecules between cells. They are formed and stored inside multivesicular bodies (MVB) until they are... (Review)
Review
Exosomes are extracellular vesicles that transport different molecules between cells. They are formed and stored inside multivesicular bodies (MVB) until they are released to the extracellular environment. MVB fuse along the plasma membrane, driving non-polarized secretion of exosomes. However, polarized signaling potentially directs MVBs to a specific point in the plasma membrane to mediate a focal delivery of exosomes. MVB polarization occurs across a broad set of cellular situations, e.g. in immune and neuronal synapses, cell migration and in epithelial sheets. In this review, we summarize the current state of the art of polarized MVB docking and the specification of secretory sites at the plasma membrane. The current view is that MVB positioning and subsequent exosome delivery requires a polarizing, cytoskeletal dependent-trafficking mechanism. In this context, we propose scenarios in which biochemical and mechanical signals could drive the polarized delivery of exosomes in highly polarized cells, such as lymphocytes, neurons and epithelia.
Topics: Animals; Biological Transport; Cell Membrane; Cell Polarity; Exosomes; Humans; Synapses
PubMed: 25614958
DOI: 10.1111/tra.12258 -
Molecular Biology of the Cell May 2023Cadherin dynamics drive morphogenesis, while defects in cadherin polarity contribute to diseases, including cancers. However, the forces polarizing cadherin membrane...
Cadherin dynamics drive morphogenesis, while defects in cadherin polarity contribute to diseases, including cancers. However, the forces polarizing cadherin membrane distribution are not well understood. We previously showed that WAVE-dependent branched actin polarizes cadherin distribution and suggested that one mechanism is protein transport. While previous studies suggested that WAVE is enriched at various endocytic organelles, the role of WAVE in protein traffic is understudied. Here we test the model that WAVE regulates cadherin by polarizing its transport. In support of this model we show that 1) endogenously tagged WAVE accumulates in vivo at several endocytic organelles, including recycling endosomes and at the Golgi; 2) likewise, cadherin protein accumulates at recycling endosomes and the Golgi; 3) loss of WAVE components reduces cadherin accumulation at apically directed RAB-11-positive recycling endosomes and increases accumulation at the Golgi. In addition, live imaging illustrates that dynamics and velocity of recycling endosomes enriched for RAB-11::GFP and RFP::RME-1 are reduced in animals depleted of WAVE components and RAB-11::GFP movements are misdirected, suggesting that WAVE powers and directs their movements. This in vivo study demonstrates the importance of WAVE in promoting polarized transport in epithelia and supports a model that WAVE promotes cell-cell adhesion and polarity by promoting cadherin transport.
Topics: Animals; Cadherins; rab GTP-Binding Proteins; Endosomes; Protein Transport; Golgi Apparatus
PubMed: 36947190
DOI: 10.1091/mbc.E22-08-0322 -
International Immunopharmacology Nov 2023Colorectal cancer (CRC) is a growing concern due to its high morbidity and mortality, and the search for effective and less toxic active substances against inflammatory...
Colorectal cancer (CRC) is a growing concern due to its high morbidity and mortality, and the search for effective and less toxic active substances against inflammatory bowel diseases has been a hot topic in the research and development of drugs against CRC. It is reported that monotropein isolated from the roots of Morinda officinalis, can improve Dextran Sodium Sulfate (DSS)-induced ulcerative colitis in mice, but its therapeutic effects and mechanisms for CRC treatment are still to be investigated. In the present study, we first used molecular docking, BLI, CESTA, and DARTS methods to detest whether monotropein targets VDR proteins. In addition, we used tumor cell conditioned co-culture and four models of macrophage polarisation to investigate the regulation of four macrophage polarisations by monotropein using RT-PCR, IF and western blot. Furthermore, we further validated the target of action of monotropein for the treatment of Azoxymethane (AOM)/DSS induced colitis associated cancer (CAC) using knockout animals. Meanwhile, we further explored the mechanism of action of monotropein in regulating polarisation by detecting JAK/STAT1-related genes and proteins. Molecular docking and biofilm interference techniques showed that monotropein bound to the VDR, and additional results from CESTA and DARTS suggested that VDR proteins are targets of monotropein. Furthermore, in tumor cell conditioned co-cultures or LPS + IFN-γ induced RAW264.7 cells, VDR translocation to the nucleus was reduced, JAK1/STAT1 signaling pathway proteins were up-regulated, and macrophages were polarised towards the M1-type after monotropein intervention. Animal models in which normal VDR or myeloid VDR was knocked out confirmed that JAK1 levels in intestinal tissues were increased after monotropein intervention, macrophages were polarised towards the M1 type, and CAC paracarcinomas were ameliorated. Taken together, the present study concluded that monotropein inhibited colitis-associated cancers through macrophage polarisation regulated by VDR/JAK1/STAT1.
PubMed: 37633235
DOI: 10.1016/j.intimp.2023.110838 -
Current Opinion in Genetics &... Feb 2022The making of an embryo and its internal organs entails the spatial coordination of cellular activities. This manifests during tissue morphogenesis as cells change... (Review)
Review
The making of an embryo and its internal organs entails the spatial coordination of cellular activities. This manifests during tissue morphogenesis as cells change shape, rearrange and divide along preferential axis and during cell differentiation. Cells live in a polarized field and respond to it by polarizing their cellular activities in the plane of the tissue by a phenomenon called planar cell polarization. This phenomenon is ubiquitous in animals and depends on a few conserved planar cell polarity (PCP) pathways. All PCP pathways share two essential characteristics: the existence of local interactions between protein complexes present at the cell surface leading to their asymmetric distribution within cells; a supracellular graded cue that aligns these cellular asymmetries at the tissue level. Here, we discuss the potential common principles of planar cell polarization by comparing the local and global mechanisms employed by the different PCP pathways identified so far. The focus of the review is on the logic of the system rather than the molecules per se.
Topics: Animals; Cell Polarity; Embryo, Mammalian; Morphogenesis; Wnt Signaling Pathway
PubMed: 34871922
DOI: 10.1016/j.gde.2021.11.001 -
Biology Open Apr 2016The epidermal patterns of all three larval instars (L1-L3) ofDrosophilaare made by one unchanging set of cells. The seven rows of cuticular denticles of all larval...
The epidermal patterns of all three larval instars (L1-L3) ofDrosophilaare made by one unchanging set of cells. The seven rows of cuticular denticles of all larval stages are consistently planar polarised, some pointing forwards, others backwards. In L1 all the predenticles originate at the back of the cells but, in L2 and L3, they form at the front or the back of the cell depending on the polarity of the forthcoming denticles. We find that, to polarise all rows, the Dachsous/Fat system is differentially utilised; in L1 it is active in the placement of the actin-based predenticles but is not crucial for the final orientation of the cuticular denticles, in L2 and L3 it is needed for placement and polarity. We find Four-jointed to be strongly expressed in the tendon cells and show how this might explain the orientation of all seven rows. Unexpectedly, we find that L3 that lack Dachsous differ from larvae lacking Fat and we present evidence that this is due to differently mislocalised Dachs. We make some progress in understanding how Dachs contributes to phenotypes of wildtype and mutant larvae and adults.
PubMed: 26935392
DOI: 10.1242/bio.017152 -
Journal of Cell Science Jan 2008The differentiation, activation and expansion of T cells are dictated by their integrated response to a complex array of extracellular signals. Recent studies provide...
The differentiation, activation and expansion of T cells are dictated by their integrated response to a complex array of extracellular signals. Recent studies provide insight into how these signals are integrated and demonstrate a key role for cell shape in many aspects of T-cell signalling. T cells polarise during migration, antigen presentation and cell division to give rise to daughter cells that can have different cell fates. In each case, the polarity of the T cell facilitates this activity. This raises the possibility that adoption of a polarised state acts as a positive feedback mechanism to enhance responses to specific signals. Similarly, in asymmetric division of other cell types, the distribution of different molecules into each daughter can have profound consequences for proliferation, death and differentiation. The mechanisms of polarity regulation are far better understood in cells such as epithelial cells, neurons and neuronal precursors, and the fertilised zygote. With the emerging parallels between polarity in these cells and T cells, we should now be able to elucidate how polarity affects signalling and cell fate determination in T cells.
Topics: Animals; Antigen Presentation; Cell Communication; Cell Differentiation; Cell Division; Cell Lineage; Cell Polarity; Cell Proliferation; Humans; Models, Biological; Models, Immunological; Receptors, Antigen, T-Cell; Signal Transduction; T-Lymphocytes
PubMed: 18187446
DOI: 10.1242/jcs.021253 -
Molecular Biology of the Cell Feb 2005Epithelial cells polarize and orient polarity in response to cell-cell and cell-matrix adhesion. Although there has been much recent progress in understanding the...
Epithelial cells polarize and orient polarity in response to cell-cell and cell-matrix adhesion. Although there has been much recent progress in understanding the general polarizing machinery of epithelia, it is largely unclear how this machinery is controlled by the extracellular environment. To explore the signals from cell-matrix interactions that control orientation of cell polarity, we have used three-dimensional culture systems in which Madin-Darby canine kidney (MDCK) cells form polarized, lumen-containing structures. We show that interaction of collagen I with apical beta1-integrins after collagen overlay of a polarized MDCK monolayer induces activation of Rac1, which is required for collagen overlay-induced tubulocyst formation. Cysts, comprised of a monolayer enclosing a central lumen, form after embedding single cells in collagen. In those cultures, addition of a beta1-integrin function-blocking antibody to the collagen matrix gives rise to cysts that have defects in the organization of laminin into the basement membrane and have inverted polarity. Normal polarity is restored by either expression of activated Rac1, or the inclusion of excess laminin-1 (LN-1). Together, our results suggest a signaling pathway in which the activation of beta1-integrins orients the apical pole of polarized cysts via a mechanism that requires Rac1 activation and laminin organization into the basement membrane.
Topics: Animals; Cell Adhesion; Cell Culture Techniques; Cell Line; Cell Polarity; Collagen Type I; Dogs; Enzyme Activation; Epithelial Cells; Integrins; Laminin; rac1 GTP-Binding Protein
PubMed: 15574881
DOI: 10.1091/mbc.e04-05-0435 -
Current Biology : CB Apr 2005The noncanonical wnt/planar cell polarity (PCP) pathway [1] regulates the mediolaterally (planarly) polarized cell protrusive activity and intercalation that drives the... (Comparative Study)
Comparative Study
The noncanonical wnt/planar cell polarity (PCP) pathway [1] regulates the mediolaterally (planarly) polarized cell protrusive activity and intercalation that drives the convergent extension movements of vertebrate gastrulation [2], yet the underlying mechanism is unknown. We report that perturbing expression of Xenopus PCP genes, Strabismus (Xstbm), Frizzled (Xfz7), and Prickle (Xpk), disrupts radially polarized fibronectin fibril assembly on mesodermal tissue surfaces, mediolaterally polarized motility, and intercalation. Polarized motility is restored in Xpk-perturbed explants but not in Xstbm- or Xfz7-perturbed explants cultured on fibronectin surfaces. The PCP complex, including Xpk, first regulates polarized surface assembly of the fibronectin matrix, which is necessary for mediolaterally polarized motility, and then, without Xpk, has an additional and necessary function in polarizing motility. These results show that the PCP complex regulates several cell polarities (radial, planar) and several processes (matrix deposition, motility), by indirect and direct mechanisms, and acts in several modes, either with all or a subset of its components, during vertebrate morphogenesis.
Topics: Animals; Cell Polarity; Cell Surface Extensions; Extracellular Matrix; Fibronectins; Fluorescent Dyes; Gastrula; Gene Expression Regulation, Developmental; Membrane Proteins; Microscopy, Confocal; Organic Chemicals; Receptors, G-Protein-Coupled; Signal Transduction; Xenopus; Xenopus Proteins
PubMed: 15854914
DOI: 10.1016/j.cub.2005.03.040