Publications by authors named "Kathleen J Green"

105 Publications

Regulation of intestinal epithelial intercellular adhesion and barrier function by desmosomal cadherin desmocollin-2.

Mol Biol Cell 2021 Apr 17;32(8):753-768. Epub 2021 Feb 17.

Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109.

The role of desmosomal cadherin desmocollin-2 (Dsc2) in regulating barrier function in intestinal epithelial cells (IECs) is not well understood. Here, we report the consequences of silencing Dsc2 on IEC barrier function in vivo using mice with inducible intestinal-epithelial-specific knockdown (KD) (). While the small intestinal gross architecture was maintained, loss of epithelial Dsc2 influenced desmosomal plaque structure, which was smaller in size and had increased intermembrane space between adjacent epithelial cells. Functional analysis revealed that loss of Dsc2 increased intestinal permeability in vivo, supporting a role for Dsc2 in the regulation of intestinal epithelial barrier function. These results were corroborated in model human IECs in which Dsc2 KD resulted in decreased cell-cell adhesion and impaired barrier function. It is noteworthy that Dsc2 KD cells exhibited delayed recruitment of desmoglein-2 (Dsg2) to the plasma membrane after calcium switch-induced intercellular junction reassembly, while E-cadherin accumulation was unaffected. Mechanistically, loss of Dsc2 increased desmoplakin (DP I/II) protein expression and promoted intermediate filament interaction with DP I/II and was associated with enhanced tension on desmosomes as measured by a Dsg2-tension sensor. In conclusion, we provide new insights on Dsc2 regulation of mechanical tension, adhesion, and barrier function in IECs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1091/mbc.E20-12-0775DOI Listing
April 2021

Proximity Ligation Assay for Detecting Protein-Protein Interactions and Protein Modifications in Cells and Tissues in Situ.

Curr Protoc Cell Biol 2020 12;89(1):e115

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.

Biochemical methods can reveal stable protein-protein interactions occurring within cells, but the ability to observe transient events and to visualize the subcellular localization of protein-protein interactions in cells and tissues in situ provides important additional information. The Proximity Ligation Assay (PLA) offers the opportunity to visualize the subcellular location of such interactions at endogenous protein levels, provided that the probes that recognize the target proteins are within 40 nm. This sensitive technique not only elucidates protein-protein interactions, but also can reveal post-translational protein modifications. The technique is useful even in cases where material is limited, such as when paraffin-embedded clinical specimens are the only available material, as well as after experimental intervention in 2D and 3D model systems. Here we describe the basic protocol for using the commercially available Proximity Ligation Assay™ materials (Sigma-Aldrich, St. Louis, MO), and incorporate details to aid the researcher in successfully performing the experiments. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Proximity ligation assay Support Protocol 1: Antigen retrieval method for formalin-fixed, paraffin-embedded tissues Support Protocol 2: Creation of custom PLA probes using the Duolink™ In Situ Probemaker Kit when commercially available probes are not suitable Basic Protocol 2: Imaging, quantification, and analysis of PLA signals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cpcb.115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8041061PMC
December 2020

Tracing the Evolutionary Origin of Desmosomes.

Curr Biol 2020 May;30(10):R535-R543

Department of Biological Sciences, 2101 E. Wesley Ave. SGM 203, University of Denver, CO 80210, USA. Electronic address:

Cadherin-based cell-cell junctions help metazoans form polarized sheets of cells, which are necessary for the development of organs and the compartmentalization of functions. The components of the protein complexes that generate cadherin-based junctions have ancient origins, with conserved elements shared between animals as diverse as sponges and vertebrates. In invertebrates, the formation and function of epithelial sheets depends on classical cadherin-containing adherens junctions, which link actin to the plasma membrane through α-, β- and p120 catenins. Vertebrates also have a new type of cadherin-based intercellular junction called the desmosome, which allowed for the creation of more complex and effective tissue barriers against environmental stress. While desmosomes have a molecular blueprint that is similar to that of adherens junctions, desmosomal cadherins - called desmogleins and desmocollins - link intermediate filaments (IFs) rather than actin to the plasma membrane through protein complexes comprising relatives of β-catenin (plakoglobin) and p120 catenin (plakophilins). In turn, desmosomal catenins interact with members of the IF-binding plakin family to create the desmosome-IF linking complex. In this Minireview, we discuss when and how desmosomal components evolved, and how their ability to anchor the highly elastic and tough IF cytoskeleton endowed vertebrates with robust tissues capable of not only resisting but also properly responding to environmental stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cub.2020.03.047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7310670PMC
May 2020

Scaling up single-cell mechanics to multicellular tissues - the role of the intermediate filament-desmosome network.

J Cell Sci 2020 03 16;133(6). Epub 2020 Mar 16.

Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA

Cells and tissues sense, respond to and translate mechanical forces into biochemical signals through mechanotransduction, which governs individual cell responses that drive gene expression, metabolic pathways and cell motility, and determines how cells work together in tissues. Mechanotransduction often depends on cytoskeletal networks and their attachment sites that physically couple cells to each other and to the extracellular matrix. One way that cells associate with each other is through Ca-dependent adhesion molecules called cadherins, which mediate cell-cell interactions through adherens junctions, thereby anchoring and organizing the cortical actin cytoskeleton. This actin-based network confers dynamic properties to cell sheets and developing organisms. However, these contractile networks do not work alone but in concert with other cytoarchitectural elements, including a diverse network of intermediate filaments. This Review takes a close look at the intermediate filament network and its associated intercellular junctions, desmosomes. We provide evidence that this system not only ensures tissue integrity, but also cooperates with other networks to create more complex tissues with emerging properties in sensing and responding to increasingly stressful environments. We will also draw attention to how defects in intermediate filament and desmosome networks result in both chronic and acquired diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1242/jcs.228031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7097224PMC
March 2020

Desmosomes:  Essential contributors to an integrated intercellular junction network.

F1000Res 2019 30;8. Epub 2019 Dec 30.

Departments of Pathology and Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.

The development of adhesive connections between cells was critical for the evolution of multicellularity and for organizing cells into complex organs with discrete compartments. Four types of intercellular junction are present in vertebrates: desmosomes, adherens junctions, tight junctions, and gap junctions. All are essential for the development of the embryonic layers and organs as well as adult tissue homeostasis. While each junction type is defined as a distinct entity, it is now clear that they cooperate physically and functionally to create a robust and functionally diverse system. During evolution, desmosomes first appeared in vertebrates as highly specialized regions at the plasma membrane that couple the intermediate filament cytoskeleton at points of strong cell-cell adhesion. Here, we review how desmosomes conferred new mechanical and signaling properties to vertebrate cells and tissues through their interactions with the existing junctional and cytoskeletal network.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12688/f1000research.20942.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6944264PMC
June 2020

Keratinocyte cadherin desmoglein 1 controls melanocyte behavior through paracrine signaling.

Pigment Cell Melanoma Res 2020 03 10;33(2):305-317. Epub 2019 Oct 10.

Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois.

The epidermis is the first line of defense against ultraviolet (UV) light from the sun. Keratinocytes and melanocytes respond to UV exposure by eliciting a tanning response dependent in part on paracrine signaling, but how keratinocyte:melanocyte communication is regulated during this response remains understudied. Here, we uncover a surprising new function for the keratinocyte-specific cell-cell adhesion molecule desmoglein 1 (Dsg1) in regulating keratinocyte:melanocyte paracrine signaling to promote the tanning response in the absence of UV exposure. Melanocytes within Dsg1-silenced human skin equivalents exhibited increased pigmentation and altered dendrite morphology, phenotypes which were confirmed in 2D culture using conditioned media from Dsg1-silenced keratinocytes. Dsg1-silenced keratinocytes increased melanocyte-stimulating hormone precursor (Pomc) and cytokine mRNA. Melanocytes cultured in media conditioned by Dsg1-silenced keratinocytes increased Mitf and Tyrp1 mRNA, TYRP1 protein, and melanin production and secretion. Melanocytes in Dsg1-silenced skin equivalents mislocalized suprabasally, reminiscent of early melanoma pagetoid behavior. Together with our previous report that UV reduces Dsg1 expression, these data support a role for Dsg1 in controlling keratinocyte:melanocyte paracrine communication and raise the possibility that a Dsg1-deficient niche contributes to pagetoid behavior, such as occurs in early melanoma development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pcmr.12826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7028503PMC
March 2020

The Role of Desmoglein 1 in Gap Junction Turnover Revealed through the Study of SAM Syndrome.

J Invest Dermatol 2020 03 26;140(3):556-567.e9. Epub 2019 Aug 26.

Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA. Electronic address:

An effective epidermal barrier requires structural and functional integration of adherens junctions, tight junctions, gap junctions (GJ), and desmosomes. Desmosomes govern epidermal integrity while GJs facilitate small molecule transfer across cell membranes. Some patients with severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome, caused by biallelic desmoglein 1 (DSG1) mutations, exhibit skin lesions reminiscent of erythrokeratodermia variabilis, caused by mutations in connexin (Cx) genes. We, therefore, examined whether SAM syndrome-causing DSG1 mutations interfere with Cx expression and GJ function. Lesional skin biopsies from SAM syndrome patients (n = 7) revealed decreased Dsg1 and Cx43 plasma membrane localization compared with control and nonlesional skin. Cultured keratinocytes and organotypic skin equivalents depleted of Dsg1 exhibited reduced Cx43 expression, rescued upon re-introduction of wild-type Dsg1, but not Dsg1 constructs modeling SAM syndrome-causing mutations. Ectopic Dsg1 expression increased cell-cell dye transfer, which Cx43 silencing inhibited, suggesting that Dsg1 promotes GJ function through Cx43. As GJA1 gene expression was not decreased upon Dsg1 loss, we hypothesized that Cx43 reduction was due to enhanced protein degradation. Supporting this, PKC-dependent Cx43 S368 phosphorylation, which signals Cx43 turnover, increased after Dsg1 depletion, while lysosomal inhibition restored Cx43 levels. These data reveal a role for Dsg1 in regulating epidermal Cx43 turnover.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jid.2019.08.433DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7039747PMC
March 2020

Definition and treatment of arrhythmogenic cardiomyopathy: an updated expert panel report.

Eur J Heart Fail 2019 08 18;21(8):955-964. Epub 2019 Jun 18.

Department of Clinical Genetics, Amsterdam Cardiovascular Sciences, University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.

It is 35 years since the first description of arrhythmogenic right ventricular cardiomyopathy (ARVC) and more than 20 years since the first reports establishing desmosomal gene mutations as a major cause of the disease. Early advances in the understanding of the clinical, pathological and genetic architecture of ARVC resulted in consensus diagnostic criteria, which proved to be sensitive but not entirely specific for the disease. In more recent years, clinical and genetic data from families and the recognition of a much broader spectrum of structural disorders affecting both ventricles and associated with a propensity to ventricular arrhythmia have raised many questions about pathogenesis, disease terminology and clinical management. In this paper, we present the conclusions of an expert round table that aimed to summarise the current state of the art in arrhythmogenic cardiomyopathies and to define future research priorities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ejhf.1534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6685753PMC
August 2019

Desmoglein 1 Regulates Invadopodia by Suppressing EGFR/Erk Signaling in an Erbin-Dependent Manner.

Mol Cancer Res 2019 05 17;17(5):1195-1206. Epub 2019 Jan 17.

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.

Loss of the desmosomal cell-cell adhesion molecule, Desmoglein 1 (Dsg1), has been reported as an indicator of poor prognosis in head and neck squamous cell carcinomas (HNSCC) overexpressing epidermal growth factor receptor (EGFR). It has been well established that EGFR signaling promotes the formation of invadopodia, actin-based protrusions formed by cancer cells to facilitate invasion and metastasis, by activating pathways leading to actin polymerization and ultimately matrix degradation. We previously showed that Dsg1 downregulates EGFR/Erk signaling by interacting with the ErbB2-binding protein Erbin (B2 teracting Protein) to promote keratinocyte differentiation. Here, we provide evidence that restoring Dsg1 expression in cells derived from HNSCC suppresses invasion by decreasing the number of invadopodia and matrix degradation. Moreover, Dsg1 requires Erbin to downregulate EGFR/Erk signaling and to fully suppress invadopodia formation. Our findings indicate a novel role for Dsg1 in the regulation of invadopodia signaling and provide potential new targets for development of therapies to prevent invadopodia formation and therefore cancer invasion and metastasis. IMPLICATIONS: Our work exposes a new pathway by which a desmosomal cadherin called Dsg1, which is lost early in head and neck cancer progression, suppresses cancer cell invadopodia formation by scaffolding ErbB2 Interacting Protein and consequent attenuation of EGF/Erk signaling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1541-7786.MCR-18-0048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6581214PMC
May 2019

Techniques to stimulate and interrogate cell-cell adhesion mechanics.

Extreme Mech Lett 2018 Apr 7;20:125-139. Epub 2017 Dec 7.

Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, United States.

Cell-cell adhesions maintain the mechanical integrity of multicellular tissues and have recently been found to act as mechanotransducers, translating mechanical cues into biochemical signals. Mechanotransduction studies have primarily focused on focal adhesions, sites of cell-substrate attachment. These studies leverage technical advances in devices and systems interfacing with living cells through cell-extracellular matrix adhesions. As reports of aberrant signal transduction originating from mutations in cell-cell adhesion molecules are being increasingly associated with disease states, growing attention is being paid to this intercellular signaling hub. Along with this renewed focus, new requirements arise for the interrogation and stimulation of cell-cell adhesive junctions. This review covers established experimental techniques for stimulation and interrogation of cell-cell adhesion from cell pairs to monolayers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.eml.2017.12.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181239PMC
April 2018

Desmoplakin maintains gap junctions by inhibiting Ras/MAPK and lysosomal degradation of connexin-43.

J Cell Biol 2018 09 29;217(9):3219-3235. Epub 2018 Jun 29.

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL

Desmoplakin (DP) is an obligate component of desmosomes, intercellular adhesive junctions that maintain the integrity of the epidermis and myocardium. Mutations in DP can cause cardiac and cutaneous disease, including arrhythmogenic cardiomyopathy (ACM), an inherited disorder that frequently results in deadly arrhythmias. Conduction defects in ACM are linked to the remodeling and functional interference with Cx43-based gap junctions that electrically and chemically couple cells. How DP loss impairs gap junctions is poorly understood. We show that DP prevents lysosomal-mediated degradation of Cx43. DP loss triggered robust activation of ERK1/2-MAPK and increased phosphorylation of S279/282 of Cx43, which signals clathrin-mediated internalization and subsequent lysosomal degradation of Cx43. RNA sequencing revealed Ras-GTPases as candidates for the aberrant activation of ERK1/2 upon loss of DP. Using a novel Ras inhibitor, Ras/Rap1-specific peptidase (RRSP), or K-Ras knockdown, we demonstrate restoration of Cx43 in DP-deficient cardiomyocytes. Collectively, our results reveal a novel mechanism for the regulation of the Cx43 life cycle by DP in cardiocutaneous models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1083/jcb.201710161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6123000PMC
September 2018

Filaggrin 2 Deficiency Results in Abnormal Cell-Cell Adhesion in the Cornified Cell Layers and Causes Peeling Skin Syndrome Type A.

J Invest Dermatol 2018 08 27;138(8):1736-1743. Epub 2018 Jun 27.

Department of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; Department of Human Molecular Genetics & Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. Electronic address:

Peeling skin syndromes form a large and heterogeneous group of inherited disorders characterized by superficial detachment of the epidermal cornified cell layers, often associated with inflammatory features. Here we report on a consanguineous family featuring noninflammatory peeling of the skin exacerbated by exposure to heat and mechanical stress. Whole exome sequencing revealed a homozygous nonsense mutation in FLG2, encoding filaggrin 2, which cosegregated with the disease phenotype in the family. The mutation was found to result in decreased FLG2 RNA levels as well as almost total absence of filaggrin 2 in the patient epidermis. Filaggrin 2 was found to be expressed throughout the cornified cell layers and to colocalize with corneodesmosin that plays a crucial role in maintaining cell-cell adhesion in this region of the epidermis. The absence of filaggrin 2 in the patient skin was associated with markedly decreased corneodesmosin expression, which may contribute to the peeling phenotype displayed by the patients. Accordingly, using the dispase dissociation assay, we showed that FLG2 downregulation interferes with keratinocyte cell-cell adhesion. Of particular interest, this effect was aggravated by temperature elevation, consistent with the clinical phenotype. Restoration of corneodesmosin levels by ectopic expression rescued cell-cell adhesion. Taken together, the present data suggest that filaggrin 2 is essential for normal cell-cell adhesion in the cornified cell layers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jid.2018.04.032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6056331PMC
August 2018

Epithelial barrier dysfunction in desmoglein-1 deficiency.

J Allergy Clin Immunol 2018 08 27;142(2):702-706.e7. Epub 2018 Apr 27.

Laboratory of Genetics of Monogenic Auto-inflammatory Diseases, Necker Branch, U1163, Necker-Enfants Malades Hospital (AP-HP), Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaci.2018.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6078820PMC
August 2018

Desmosomal cadherin association with Tctex-1 and cortactin-Arp2/3 drives perijunctional actin polymerization to promote keratinocyte delamination.

Nat Commun 2018 03 13;9(1):1053. Epub 2018 Mar 13.

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, 60611, IL, USA.

The epidermis is a multi-layered epithelium that serves as a barrier against water loss and environmental insults. Its morphogenesis occurs through a tightly regulated program of biochemical and architectural changes during which basal cells commit to differentiate and move towards the skin's surface. Here, we reveal an unexpected role for the vertebrate cadherin desmoglein 1 (Dsg1) in remodeling the actin cytoskeleton to promote the transit of basal cells into the suprabasal layer through a process of delamination, one mechanism of epidermal stratification. Actin remodeling requires the interaction of Dsg1 with the dynein light chain, Tctex-1 and the actin scaffolding protein, cortactin. We demonstrate that Tctex-1 ensures the correct membrane compartmentalization of Dsg1-containing desmosomes, allowing cortactin/Arp2/3-dependent perijunctional actin polymerization and decreasing tension at E-cadherin junctions to promote keratinocyte delamination. Moreover, Dsg1 is sufficient to enable simple epithelial cells to exit a monolayer to form a second layer, highlighting its morphogenetic potential.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-018-03414-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5849617PMC
March 2018

Research Techniques Made Simple: Methodology and Applications of Förster Resonance Energy Transfer (FRET) Microscopy.

J Invest Dermatol 2017 11;137(11):e185-e191

Department of Pathology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA; Department of Dermatology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA. Electronic address:

Classical biochemical techniques have contributed a great deal to our understanding of the mechanisms regulating fundamental biological processes. However, these approaches are typically end-point, population-based assays and are often insufficient in examining transient molecular events. Förster resonance energy transfer (FRET) microscopy is a powerful technique capable of investigating dynamic interactions between proteins and a plethora of biochemical signaling events based on the development of specific biosensors. This technique exploits the principle that when FRET occurs, energy from a donor fluorophore is transferred to an acceptor fluorophore only when certain conditions are met. These include dependence on both distance and fluorophore orientation. In this article, applications of FRET microscopy to protein interactions and modifications are discussed, and examples are given of the types of biosensors that can be developed. There are a number of methods to measure FRET. The most common modalities and specific advantages and shortcomings for each are reviewed. Finally, general considerations and guidelines for choosing a method are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jid.2017.09.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5800528PMC
November 2017

A rim-and-spoke hypothesis to explain the biomechanical roles for cytoplasmic intermediate filament networks.

J Cell Sci 2017 Oct;130(20):3437-3445

RWTH Aachen University, Institute of Molecular and Cellular Anatomy, Wendlingweg 2, 52074 Aachen, Germany

Textbook images of keratin intermediate filament (IF) networks in epithelial cells and the functional compromization of the epidermis by keratin mutations promulgate a mechanical role for this important cytoskeletal component. In stratified epithelia, keratin filaments form prominent radial spokes that are focused onto cell-cell contact sites, i.e. the desmosomes. In this Hypothesis, we draw attention to a subset of keratin filaments that are apposed to the plasma membrane. They form a rim of filaments interconnecting the desmosomes in a circumferential network. We hypothesize that they are part of a rim-and-spoke arrangement of IFs in epithelia. From our review of the literature, we extend this functional role for the subplasmalemmal rim of IFs to any cell, in which plasma membrane support is required, provided these filaments connect directly or indirectly to the plasma membrane. Furthermore, cytoplasmic IF networks physically link the outer nuclear and plasma membranes, but their participation in mechanotransduction processes remain largely unconsidered. Therefore, we also discuss the potential biomechanical and mechanosensory role(s) of the cytoplasmic IF network in terms of such a rim (i.e. subplasmalemmal)-and-spoke arrangement for cytoplasmic IF networks.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1242/jcs.202168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6518161PMC
October 2017

Adherens Junctions and Desmosomes Coordinate Mechanics and Signaling to Orchestrate Tissue Morphogenesis and Function: An Evolutionary Perspective.

Cold Spring Harb Perspect Biol 2018 11 1;10(11). Epub 2018 Nov 1.

University of Cologne, Department of Dermatology, Cologne Excellence Cluster on Stress Responses in Aging Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC) at the CECAD Research Center, 50931 Cologne, Germany.

Cadherin-based adherens junctions (AJs) and desmosomes are crucial to couple intercellular adhesion to the actin or intermediate filament cytoskeletons, respectively. As such, these intercellular junctions are essential to provide not only integrity to epithelia and other tissues but also the mechanical machinery necessary to execute complex morphogenetic and homeostatic intercellular rearrangements. Moreover, these spatially defined junctions serve as signaling hubs that integrate mechanical and chemical pathways to coordinate tissue architecture with behavior. This review takes an evolutionary perspective on how the emergence of these two essential intercellular junctions at key points during the evolution of multicellular animals afforded metazoans with new opportunities to integrate adhesion, cytoskeletal dynamics, and signaling. We discuss known literature on cross-talk between the two junctions and, using the skin epidermis as an example, provide a model for how these two junctions function in concert to orchestrate tissue organization and function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/cshperspect.a029207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6211388PMC
November 2018

The desmoplakin-intermediate filament linkage regulates cell mechanics.

Mol Biol Cell 2017 Nov 11;28(23):3156-3164. Epub 2017 May 11.

Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208

The translation of mechanical forces into biochemical signals plays a central role in guiding normal physiological processes during tissue development and homeostasis. Interfering with this process contributes to cardiovascular disease, cancer progression, and inherited disorders. The actin-based cytoskeleton and its associated adherens junctions are well-established contributors to mechanosensing and transduction machinery; however, the role of the desmosome-intermediate filament (DSM-IF) network is poorly understood in this context. Because a force balance among different cytoskeletal systems is important to maintain normal tissue function, knowing the relative contributions of these structurally integrated systems to cell mechanics is critical. Here we modulated the interaction between DSMs and IFs using mutant forms of desmoplakin, the protein bridging these structures. Using micropillar arrays and atomic force microscopy, we demonstrate that strengthening the DSM-IF interaction increases cell-substrate and cell-cell forces and cell stiffness both in cell pairs and sheets of cells. In contrast, disrupting the interaction leads to a decrease in these forces. These alterations in cell mechanics are abrogated when the actin cytoskeleton is dismantled. These data suggest that the tissue-specific variability in DSM-IF network composition provides an opportunity to differentially regulate tissue mechanics by balancing and tuning forces among cytoskeletal systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1091/mbc.E16-07-0520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687018PMC
November 2017

Epidermolytic Ichthyosis Sine Epidermolysis.

Am J Dermatopathol 2017 Jun;39(6):440-444

*Department of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; †Department of Human Molecular Genetics & Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; ‡Department of Dermatology, Kirov State Medical Academy, Kirov, Russia; §Department of Pathology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; ¶Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; ‖INSERM UMR 1163, Imagine Institute, University Paris Descartes Sorbonne Cité, Paris, France; **Department of Genetics, Necker hospital for sick children, APHP, Paris, France; ††Department of Dermatology and Allergology, Ludwig-Maximilian-University, Munich, Germany; and Departments of ‡‡Pathology, §§Dermatology, and ¶¶Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL.

Epidermolytic ichthyosis (EI) is a rare disorder of cornification caused by mutations in KRT1 and KRT10, encoding two suprabasal epidermal keratins. Because of the variable clinical features and severity of the disease, histopathology is often required to correctly direct the molecular analysis. EI is characterized by hyperkeratosis and vacuolar degeneration of the upper epidermis, also known as epidermolytic hyperkeratosis, hence the name of the disease. In the current report, the authors describe members of 2 families presenting with clinical features consistent with EI. The patients were shown to carry classical mutations in KRT1 or KRT10, but did not display epidermolytic changes on histology. These observations underscore the need to remain aware of the limitations of pathological features when considering a diagnosis of EI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/DAD.0000000000000674DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5489912PMC
June 2017

Intermediate Filaments and the Plasma Membrane.

Cold Spring Harb Perspect Biol 2017 Jan 3;9(1). Epub 2017 Jan 3.

Departments of Dermatology and Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611.

A variety of intermediate filament (IF) types show intricate association with plasma membrane proteins, including receptors and adhesion molecules. The molecular basis of linkage of IFs to desmosomes at sites of cell-cell interaction and hemidesmosomes at sites of cell-matrix adhesion has been elucidated and involves IF-associated proteins. However, IFs also interact with focal adhesions and cell-surface molecules, including dystroglycan. Through such membrane interactions, it is well accepted that IFs play important roles in the establishment and maintenance of tissue integrity. However, by organizing cell-surface complexes, IFs likely regulate, albeit indirectly, signaling pathways that are key to tissue homeostasis and repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1101/cshperspect.a025866DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5204322PMC
January 2017

SVEP1 plays a crucial role in epidermal differentiation.

Exp Dermatol 2017 05 20;26(5):423-430. Epub 2017 Feb 20.

Department of Dermatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.

SVEP1 is a recently identified multidomain cell adhesion protein, homologous to the mouse polydom protein, which has been shown to mediate cell-cell adhesion in an integrin-dependent manner in osteogenic cells. In this study, we characterized SVEP1 function in the epidermis. SVEP1 was found by qRT-PCR to be ubiquitously expressed in human tissues, including the skin. Confocal microscopy revealed that SVEP1 is normally mostly expressed in the cytoplasm of basal and suprabasal epidermal cells. Downregulation of SVEP1 expression in primary keratinocytes resulted in decreased expression of major epidermal differentiation markers. Similarly, SVEP1 downregulation was associated with disturbed differentiation and marked epidermal acanthosis in three-dimensional skin equivalents. In contrast, the dispase assay failed to demonstrate significant differences in adhesion between keratinocytes expressing normal vs low levels of SVEP1. Homozygous Svep1 knockout mice were embryonic lethal. Thus, to assess the importance of SVEP1 for normal skin homoeostasis in vivo, we downregulated SVEP1 in zebrafish embryos with a Svep1-specific splice morpholino. Scanning electron microscopy revealed a rugged epidermis with perturbed microridge formation in the centre of the keratinocytes of morphant larvae. Transmission electron microscopy analysis demonstrated abnormal epidermal cell-cell adhesion with disadhesion between cells in Svep1-deficient morphant larvae compared to controls. In summary, our results indicate that SVEP1 plays a critical role during epidermal differentiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/exd.13256DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543306PMC
May 2017

Degrees of Freedom: Your Future in Biomedical Research.

J Invest Dermatol 2016 06;136(6):1073-1076

University of Cologne, Department of Dermatology, Cologne Excellence Cluster on Stress Responses in Aging Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC) at the CECAD Research Center, Joseph Stelzmannstrasse 26, 50931, Cologne, Germany.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jid.2016.03.025DOI Listing
June 2016

Plakophilin-2 loss promotes TGF-β1/p38 MAPK-dependent fibrotic gene expression in cardiomyocytes.

J Cell Biol 2016 Feb 8;212(4):425-38. Epub 2016 Feb 8.

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611

Members of the desmosome protein family are integral components of the cardiac area composita, a mixed junctional complex responsible for electromechanical coupling between cardiomyocytes. In this study, we provide evidence that loss of the desmosomal armadillo protein Plakophilin-2 (PKP2) in cardiomyocytes elevates transforming growth factor β1 (TGF-β1) and p38 mitogen-activated protein kinase (MAPK) signaling, which together coordinate a transcriptional program that results in increased expression of profibrotic genes. Importantly, we demonstrate that expression of Desmoplakin (DP) is lost upon PKP2 knockdown and that restoration of DP expression rescues the activation of this TGF-β1/p38 MAPK transcriptional cascade. Tissues from PKP2 heterozygous and DP conditional knockout mouse models also exhibit elevated TGF-β1/p38 MAPK signaling and induction of fibrotic gene expression in vivo. These data therefore identify PKP2 and DP as central players in coordination of desmosome-dependent TGF-β1/p38 MAPK signaling in cardiomyocytes, pathways known to play a role in different types of cardiac disease, such as arrhythmogenic or hypertrophic cardiomyopathy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1083/jcb.201507018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4754716PMC
February 2016

In Vitro Model of the Epidermis: Connecting Protein Function to 3D Structure.

Methods Enzymol 2016 20;569:287-308. Epub 2015 Aug 20.

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA; Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois, USA. Electronic address:

Much of our understanding of the biological processes that underlie cellular functions in humans, such as cell-cell communication, intracellular signaling, and transcriptional and posttranscriptional control of gene expression, has been acquired from studying cells in a two-dimensional (2D) tissue culture environment. However, it has become increasingly evident that the 2D environment does not support certain cell functions. The need for more physiologically relevant models prompted the development of three-dimensional (3D) cultures of epithelial, endothelial, and neuronal tissues (Shamir & Ewald, 2014). These models afford investigators with powerful tools to study the contribution of spatial organization, often in the context of relevant extracellular matrix and stromal components, to cellular and tissue homeostasis in normal and disease states.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/bs.mie.2015.07.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4870045PMC
October 2016

Dominant de novo DSP mutations cause erythrokeratodermia-cardiomyopathy syndrome.

Hum Mol Genet 2016 Jan 24;25(2):348-57. Epub 2015 Nov 24.

Department of Genetics, Department of Dermatology and Department of Pathology, Yale University School of Medicine, New Haven, CT, USA,

Disorders of keratinization (DOK) show marked genotypic and phenotypic heterogeneity. In most cases, disease is primarily cutaneous, and further clinical evaluation is therefore rarely pursued. We have identified subjects with a novel DOK featuring erythrokeratodermia and initially-asymptomatic, progressive, potentially fatal cardiomyopathy, a finding not previously associated with erythrokeratodermia. We show that de novo missense mutations clustered tightly within a single spectrin repeat of DSP cause this novel cardio-cutaneous disorder, which we term erythrokeratodermia-cardiomyopathy (EKC) syndrome. We demonstrate that DSP mutations in our EKC syndrome subjects affect localization of desmosomal proteins and connexin 43 in the skin, and result in desmosome aggregation, widening of intercellular spaces, and lipid secretory defects. DSP encodes desmoplakin, a primary component of desmosomes, intercellular adhesion junctions most abundant in the epidermis and heart. Though mutations in DSP are known to cause other disorders, our cohort features the unique clinical finding of severe whole-body erythrokeratodermia, with distinct effects on localization of desmosomal proteins and connexin 43. These findings add a severe, previously undescribed syndrome featuring erythrokeratodermia and cardiomyopathy to the spectrum of disease caused by mutation in DSP, and identify a specific region of the protein critical to the pathobiology of EKC syndrome and to DSP function in the heart and skin.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddv481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4706118PMC
January 2016

Severe dermatitis, multiple allergies, and metabolic wasting syndrome caused by a novel mutation in the N-terminal plakin domain of desmoplakin.

J Allergy Clin Immunol 2015 Nov 12;136(5):1268-76. Epub 2015 Jun 12.

Clinical Medicine, Trinity College Dublin, Dublin, Ireland; Pediatric Dermatology, Our Lady's Children's Hospital Crumlin, Dublin, Ireland; National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland. Electronic address:

Background: Severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome is a recently recognized syndrome caused by mutations in the desmoglein 1 gene (DSG1). To date, only 3 families have been reported.

Objective: We studied a new case of SAM syndrome known to have no mutations in DSG1 to detail the clinical, histopathologic, immunofluorescent, and ultrastructural phenotype and to identify the underlying molecular mechanisms in this rare genodermatosis.

Methods: Histopathologic, electron microscopy, and immunofluorescent studies were performed. Whole-exome sequencing data were interrogated for mutations in desmosomal and other skin structural genes, followed by Sanger sequencing of candidate genes in the patient and his parents.

Results: No mutations were identified in DSG1; however, a novel de novo heterozygous missense c.1757A>C mutation in the desmoplakin gene (DSP) was identified in the patient, predicting the amino acid substitution p.His586Pro in the desmoplakin polypeptide.

Conclusions: SAM syndrome can be caused by mutations in both DSG1 and DSP. Knowledge of this genetic heterogeneity is important for both analysis of patients and genetic counseling of families. This condition and these observations reinforce the importance of heritable skin barrier defects, in this case desmosomal proteins, in the pathogenesis of atopic disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaci.2015.05.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4649901PMC
November 2015

Human Schlafen 5 (SLFN5) Is a Regulator of Motility and Invasiveness of Renal Cell Carcinoma Cells.

Mol Cell Biol 2015 Aug 26;35(15):2684-98. Epub 2015 May 26.

Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Division of Hematology-Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Division of Hematology-Oncology, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA

We provide evidence that human SLFN5, an interferon (IFN)-inducible member of the Schlafen (SLFN) family of proteins, exhibits key roles in controlling motility and invasiveness of renal cell carcinoma (RCC) cells. Our studies define the mechanism by which this occurs, demonstrating that SLFN5 negatively controls expression of the matrix metalloproteinase 1 gene (MMP-1), MMP-13, and several other genes involved in the control of malignant cell motility. Importantly, our data establish that SLFN5 expression correlates with a better overall survival in a large cohort of patients with RCC. The inverse relationship between SLFN5 expression and RCC aggressiveness raises the possibility of developing unique therapeutic approaches in the treatment of RCC, by modulating SLFN5 expression.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/MCB.00019-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524119PMC
August 2015

GSK3- and PRMT-1-dependent modifications of desmoplakin control desmoplakin-cytoskeleton dynamics.

J Cell Biol 2015 Mar;208(5):597-612

Department of Pathology and Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 Department of Pathology and Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611

Intermediate filament (IF) attachment to intercellular junctions is required for skin and heart integrity, but how the strength and dynamics of this attachment are modulated during normal and pathological remodeling is poorly understood. We show that glycogen synthase kinase 3 (GSK3) and protein arginine methyltransferase 1 (PRMT-1) cooperate to orchestrate a series of posttranslational modifications on the IF-anchoring protein desmoplakin (DP) that play an essential role in coordinating cytoskeletal dynamics and cellular adhesion. Front-end electron transfer dissociation mass spectrometry analyses of DP revealed six novel serine phosphorylation sites dependent on GSK3 signaling and four novel arginine methylation sites including R2834, the mutation of which has been associated with arrhythmogenic cardiomyopathy (AC). Inhibition of GSK3 or PRMT-1 or overexpression of the AC-associated mutant R2834H enhanced DP-IF associations and delayed junction assembly. R2834H blocked the GSK3 phosphorylation cascade and reduced DP-GSK3 interactions in cultured keratinocytes and in the hearts of transgenic R2834H DP mice. Interference with this regulatory machinery may contribute to skin and heart diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1083/jcb.201406020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4347645PMC
March 2015

Desmosome regulation and signaling in disease.

Cell Tissue Res 2015 Jun 19;360(3):501-12. Epub 2015 Feb 19.

Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.

Desmosomes are cell-cell adhesive organelles with a well-known role in forming strong intercellular adhesion during embryogenesis and in adult tissues subject to mechanical stress, such as the heart and skin. More recently, desmosome components have also emerged as cell signaling regulators. Loss of expression or interference with the function of desmosome molecules results in diseases of the heart and skin and contributes to cancer progression. However, the underlying molecular mechanisms that result in inherited and acquired disorders remain poorly understood. To address this question, researchers are directing their studies towards determining the functions that occur inside and outside of the junctions and the extent to which functions are adhesion-dependent or independent. This review focuses on recent discoveries that provide insights into the role of desmosomes and desmosome components in cell signaling and disease; wherever possible, we address molecular functions within and outside of the adhesive structure.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00441-015-2136-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4489137PMC
June 2015