-
Frontiers in Immunology 2021Periodontitis (PD) is a common chronic infectious disease. The local inflammatory response in the host may cause the destruction of supporting periodontal tissue.... (Review)
Review
Periodontitis (PD) is a common chronic infectious disease. The local inflammatory response in the host may cause the destruction of supporting periodontal tissue. Macrophages play a variety of roles in PD, including regulatory and phagocytosis. Moreover, under the induction of different factors, macrophages polarize and form different functional phenotypes. Among them, M1-type macrophages with proinflammatory functions and M2-type macrophages with anti-inflammatory functions are the most representative, and both of them can regulate the tendency of the immune system to exert proinflammatory or anti-inflammatory functions. M1 and M2 macrophages are involved in the destructive and reparative stages of PD. Due to the complex microenvironment of PD, the dynamic development of PD, and various local mediators, increasing attention has been given to the study of macrophage polarization in PD. This review summarizes the role of macrophage polarization in the development of PD and its research progress.
Topics: Animals; Cell Polarity; Cytokines; Humans; Janus Kinases; Macrophages; NF-kappa B; Periodontitis; Periodontium; STAT Transcription Factors; Signal Transduction
PubMed: 34950140
DOI: 10.3389/fimmu.2021.763334 -
Frontiers in Immunology 2020Cartilage lesions and osteoarthritis (OA) presents an ever-increasing clinical and socioeconomic burden. Synovial inflammation and articular inflammatory environment are... (Review)
Review
Cartilage lesions and osteoarthritis (OA) presents an ever-increasing clinical and socioeconomic burden. Synovial inflammation and articular inflammatory environment are the key factor for chondrocytes apoptosis and hypertrophy, ectopic bone formation and OA progression. To effectively treat OA, it is critical to develop a drug that skews inflammation toward a pro-chondrogenic microenvironment. In this narrative and critical review, we aim to see the potential use of immune cells modulation or cell therapy as therapeutic alternatives to OA patients. Macrophages are immune cells that are present in synovial lining, with different roles depending on their subtypes. These cells can polarize to pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes, being the latter associated with wound-healing by the production of ARG-1 and pro-chondrogenic cytokines, such as IL-10, IL-1RA, and TGF-b. Emerging evidence reveals that macrophage shift can be determined by several stimuli, apart from the conventional IL-4, IL-13, and IL-10. Evidences show the potential of physical exercise to induce type 2 response, favoring M2 polarization. Moreover, macrophages in contact with oxLDL have effect on the production of anabolic mediators as TGF-b. In the same direction, type II collagen, that plays a critical role in development and maturation process of chondrocytes, can also induce M2 macrophages, increasing TGF-b. The mTOR pathway activation in macrophages was shown to be able to polarize macrophages , though further studies are required. The possibility to use mesenchymal stem cells (MSCs) in cartilage restoration have a more concrete literature, besides, MSCs also have the capability to induce M2 macrophages. In the other direction, M1 polarized macrophages inhibit the proliferation and viability of MSCs and impair their ability to immunosuppress the environment, preventing cartilage repair. Therefore, even though MSCs therapeutic researches advances, other sources of M2 polarization are attractive issues, and further studies will contribute to the possibility to manipulate this polarization and to use it as a therapeutic approach in OA patients.
Topics: Animals; Cartilage, Articular; Cell Polarity; Cell- and Tissue-Based Therapy; Humans; Immunomodulation; Macrophage Activation; Macrophages; Mesenchymal Stem Cells; Osteoarthritis; Regeneration; Synovitis
PubMed: 32117263
DOI: 10.3389/fimmu.2020.00111 -
Journal of Cell Science Apr 2017Cells exhibit morphological and molecular asymmetries that are broadly categorized as cell polarity. The cell polarity established in early embryos prefigures the... (Review)
Review
Cells exhibit morphological and molecular asymmetries that are broadly categorized as cell polarity. The cell polarity established in early embryos prefigures the macroscopic anatomical asymmetries characteristic of adult animals. For example, eggs and early embryos have polarized distributions of RNAs and proteins that generate global anterior/posterior and dorsal/ventral axes. The molecular programs that polarize embryos are subsequently reused in multiple contexts. Epithelial cells require apical/basal polarity to establish their barrier function. Migrating cells polarize in the direction of movement, creating distinct leading and trailing structures. Asymmetrically dividing stem cells partition different molecules between themselves and their daughter cells. Cell polarity can develop , be maintained through rounds of cell division and be dynamically remodeled. In this Cell Science at a Glance review and poster, we describe molecular asymmetries that underlie cell polarity in several cellular contexts. We highlight multiple developmental systems that first establish cell/developmental polarity, and then maintain it. Our poster showcases repeated use of the Par, Scribble and Crumbs polarity complexes, which drive the development of cell polarity in many cell types and organisms. We then briefly discuss the diverse and dynamic changes in cell polarity that occur during cell migration, asymmetric cell division and in planar polarized tissues.
Topics: Animals; Asymmetric Cell Division; Caenorhabditis elegans; Cell Movement; Cell Polarity; Humans; Multiprotein Complexes; Signal Transduction
PubMed: 28365593
DOI: 10.1242/jcs.188599 -
The Journal of Histochemistry and... Oct 2021Collagen has a major role in the structural organization of tendons. Picrosirius red (PSR) staining viewed under polarized light microscopy is the standard method to...
Collagen has a major role in the structural organization of tendons. Picrosirius red (PSR) staining viewed under polarized light microscopy is the standard method to evaluate the organization of collagen fibers in tissues. It is also used to distinguish between type I and type III collagen in tissue sections. However, accurate analysis and interpretation of PSR images are challenging because of technical factors and historical misconceptions. The aim of this study was to clarify whether collagen types I and III can be distinguished by PSR staining in rat Achilles tendons, using double immunohistochemistry as the positive control. Our findings showed that PSR staining viewed with polarized light microscopy was suitable for qualitative and quantitative assessment of total collagen but was not able to distinguish collagen types. We found it critical to use a polarizing microscope equipped with a rotating stage; tendon section orientation at 45° with respect to crossed polarizers was optimal for the qualitative and quantitative assessment of collagen organization. Immunohistochemistry was superior to PSR staining for detection of collagen type III. We also compared formalin and Bouin solution as fixatives. Both produced similar birefringence, but formalin-fixed tendons provided higher quality histological detail with both hematoxylin-eosin and immunostaining.
Topics: Animals; Azo Compounds; Collagen Type I; Collagen Type III; Rats; Rats, Sprague-Dawley; Staining and Labeling; Tendons
PubMed: 34549650
DOI: 10.1369/00221554211046777 -
Journal of Cell Science Aug 2014Cell polarity is characterised by differences in structure, composition and function between at least two poles of a cell. In epithelial cells, these spatial differences... (Review)
Review
Cell polarity is characterised by differences in structure, composition and function between at least two poles of a cell. In epithelial cells, these spatial differences allow for the formation of defined apical and basal membranes. It has been increasingly recognised that cell-matrix interactions and integrins play an essential role in creating epithelial cell polarity, although key gaps in our knowledge remain. This Commentary will discuss the mounting evidence for the role of integrins in polarising epithelial cells. We build a model in which both inside-out signals to polarise basement membrane assembly at the basal surface, and outside-in signals to control microtubule apical-basal orientation and vesicular trafficking are required for establishing and maintaining the orientation of epithelial cell polarity. Finally, we discuss the relevance of the basal integrin polarity axis to cancer. This article is part of a Minifocus on Establishing polarity.
Topics: Animals; Basement Membrane; Cell Polarity; Epithelial Cells; Humans; Integrins; Microtubules; Neoplasms
PubMed: 24994933
DOI: 10.1242/jcs.146142 -
Journal of Integrative Plant Biology Jan 2020Cell polarity plays an important role in a wide range of biological processes in plant growth and development. Cell polarity is manifested as the asymmetric distribution... (Review)
Review
Cell polarity plays an important role in a wide range of biological processes in plant growth and development. Cell polarity is manifested as the asymmetric distribution of molecules, for example, proteins and lipids, at the plasma membrane and/or inside of a cell. Here, we summarize a few polarized proteins that have been characterized in plants and we review recent advances towards understanding the molecular mechanism for them to polarize at the plasma membrane. Multiple mechanisms, including membrane trafficking, cytoskeletal activities, and protein phosphorylation, and so forth define the polarized plasma membrane domains. Recent discoveries suggest that the polar positioning of the proteo-lipid membrane domain may instruct the formation of polarity complexes in plants. In this review, we highlight the factors and regulators for their functions in establishing the membrane asymmetries in plant development. Furthermore, we discuss a few outstanding questions to be addressed to better understand the mechanisms by which cell polarity is regulated in plants.
Topics: Cell Membrane; Cell Polarity; Homeostasis; Plant Cells; Plant Proteins; Plants
PubMed: 31889400
DOI: 10.1111/jipb.12904 -
The Plant Cell Jan 2022Having a sense of direction is a fundamental cellular trait that can determine cell shape, division orientation, or function, and ultimately the formation of a... (Review)
Review
Having a sense of direction is a fundamental cellular trait that can determine cell shape, division orientation, or function, and ultimately the formation of a functional, multicellular body. Cells acquire and integrate directional information by establishing discrete subcellular domains along an axis with distinct molecular profiles, a process known as cell polarization. Insight into the principles and mechanisms underlying cell polarity has been propelled by decades of extensive research mostly in yeast and animal models. Our understanding of cell polarity establishment in plants, which lack most of the regulatory molecules identified in other eukaryotes, is more limited, but significant progress has been made in recent years. In this review, we explore how plant cells coordinately establish stable polarity axes aligned with the organ axes, highlighting similarities in the molecular logic used to polarize both plant and animal cells. We propose a classification system for plant cell polarity events and nomenclature guidelines. Finally, we provide a deep phylogenetic analysis of polar proteins and discuss the evolution of polarity machineries in plants.
Topics: Biological Evolution; Cell Polarity; Phylogeny; Plant Cells; Plant Physiological Phenomena; Plant Proteins
PubMed: 34338785
DOI: 10.1093/plcell/koab203 -
Seminars in Cell & Developmental Biology May 2013The mechanosensory hair cells of the inner ear have emerged as one of the primary models for studying the development of planar polarity in vertebrates. Planar polarity... (Review)
Review
The mechanosensory hair cells of the inner ear have emerged as one of the primary models for studying the development of planar polarity in vertebrates. Planar polarity is the polarized organization of cells or cellular structures in the plane of an epithelium. For hair cells, planar polarity is manifest at the subcellular level in the polarized organization of the stereociliary bundle and at the cellular level in the coordinated orientation of stereociliary bundles between adjacent cells. This latter organization is commonly called Planar Cell Polarity and has been described in the greatest detail for auditory hair cells of the cochlea. A third level of planar polarity, referred to as tissue polarity, occurs in the utricular and saccular maculae; two inner ear sensory organs that use hair cells to detect linear acceleration and gravity. In the utricle and saccule hair cells are divided between two groups that have opposite stereociliary bundle polarities and, as a result, are able to detect movements in opposite directions. Thus vestibular hair cells are a unique model system for studying planar polarity because polarization develops at three different anatomical scales in the same sensory organ. Moreover the system has the potential to be used to dissect functional interactions between molecules regulating planar polarity at each of the three levels. Here the significance of planar polarity on vestibular system function will be discussed, and the molecular mechanisms associated with development of planar polarity at each anatomical level will be reviewed. Additional aspects of planar polarity that are unique to the vestibular maculae will also be introduced.
Topics: Animals; Cell Polarity; Frizzled Receptors; Gene Expression Regulation, Developmental; Hair Cells, Auditory; Humans; LIM Domain Proteins; Mechanotransduction, Cellular; Morphogenesis; Saccule and Utricle; Sensory Receptor Cells; Stereocilia
PubMed: 23507521
DOI: 10.1016/j.semcdb.2013.03.001 -
Genome Biology and Evolution Apr 2020Introgressive hybridization results in the transfer of genetic material between species, often with fitness implications for the recipient species. The development of...
Introgressive hybridization results in the transfer of genetic material between species, often with fitness implications for the recipient species. The development of statistical methods for detecting the signatures of historical introgression in whole-genome data has been a major area of focus. Although existing techniques are able to identify the taxa that exchanged genes during introgression using a four-taxon system, most methods do not explicitly distinguish which taxon served as donor and which as recipient during introgression (i.e., polarization of introgression directionality). Existing methods that do polarize introgression are often only able to do so when there is a fifth taxon available and that taxon is sister to one of the taxa involved in introgression. Here, we present divergence-based introgression polarization (DIP), a method for polarizing introgression using patterns of sequence divergence across whole genomes, which operates in a four-taxon context. Thus, DIP can be applied to infer the directionality of introgression when additional taxa are not available. We use simulations to show that DIP can polarize introgression and identify potential sources of bias in the assignment of directionality, and we apply DIP to a well-described hominin introgression event.
Topics: Animals; Biological Evolution; Cell Nucleus; DNA, Mitochondrial; Gene Flow; Genetic Introgression; Genome; Hominidae; Humans
PubMed: 32219392
DOI: 10.1093/gbe/evaa053 -
EMBO Reports Dec 2023Planar cell polarity (PCP) signaling polarizes epithelial cells within the plane of an epithelium. Core PCP signaling components adopt asymmetric subcellular...
Planar cell polarity (PCP) signaling polarizes epithelial cells within the plane of an epithelium. Core PCP signaling components adopt asymmetric subcellular localizations within cells to both polarize and coordinate polarity between cells. Achieving subcellular asymmetry requires additional effectors, including some mediating post-translational modifications of core components. Identification of such proteins is challenging due to pleiotropy. We used mass spectrometry-based proximity labeling proteomics to identify such regulators in the Drosophila wing. We identified the catalytic subunit of protein phosphatase1, Pp1-87B, and show that it regulates core protein polarization. Pp1-87B interacts with the core protein Van Gogh and at least one serine/threonine kinase, Dco/CKIε, that is known to regulate PCP. Pp1-87B modulates Van Gogh subcellular localization and directs its dephosphorylation in vivo. PNUTS, a Pp1 regulatory subunit, also modulates PCP. While the direct substrate(s) of Pp1-87B in control of PCP is not known, our data support the model that cycling between phosphorylated and unphosphorylated forms of one or more core PCP components may regulate acquisition of asymmetry. Finally, our screen serves as a resource for identifying additional regulators of PCP signaling.
Topics: Animals; Cell Polarity; Drosophila Proteins; Membrane Proteins; Protein Phosphatase 1; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Signal Transduction
PubMed: 37975164
DOI: 10.15252/embr.202356997