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Journal of Personalized Medicine Jan 2024Desmoplakin (DSP) is a large (~260 kDa) protein found in the desmosome, the subcellular structure that links the intermediate filament network of one cell to its...
Desmoplakin (DSP) is a large (~260 kDa) protein found in the desmosome, the subcellular structure that links the intermediate filament network of one cell to its neighbor. A mutation "hot-spot" within the NH-terminal of the DSP protein (residues 299-515) is associated with arrhythmogenic cardiomyopathy. In a subset of variants, disease is linked to calpain hypersensitivity. Previous studies show that calpain hypersensitivity can be corrected in vitro through the addition of a bulky residue neighboring the cleavage site, suggesting that physically blocking calpain accessibility is a viable strategy to restore DSP levels. Here, we aim to find drug-like molecules that also block calpain-dependent degradation of DSP. To do this, we screened ~2500 small molecules to identify compounds that specifically rescue DSP protein levels in the presence of proteases. We find that several molecules, including sodium dodecyl sulfate, palmitoylethanolamide, GW0742, salirasib, eprosarten mesylate, and GSK1838705A prevent wildtype and disease-variant-carrying DSP protein degradation in the presence of both trypsin and calpain without altering protease function. Computational screenings did not predict which molecules would protect DSP, likely due to a lack of specific DSP-drug interactions. Molecular dynamic simulations of DSP-drug complexes suggest that some long hydrophobic molecules can bind in a shallow hydrophobic groove that runs alongside the protease cleavage site. Identification of these compounds lays the groundwork for pharmacological treatment for individuals harboring these hypersensitive DSP variants.
PubMed: 38392596
DOI: 10.3390/jpm14020163 -
SAGE Open Medical Case Reports 2024COVID-19 has been implicated in various cutaneous autoimmune diseases. Pemphigus is a group of autoimmune blistering diseases that target the desmosomal complexes....
COVID-19 has been implicated in various cutaneous autoimmune diseases. Pemphigus is a group of autoimmune blistering diseases that target the desmosomal complexes. Pemphigus triggered by COVID-19 has been seldom reported in the literature and remains both a diagnostic and therapeutic challenge. We report a case of COVID-19-induced pemphigus that responded well to prednisone and mycophenolate mofetil after 9 months from initial presentation. On histologic examination, both intercellular and basement membrane staining were noted. Indirect immunofluorescence staining was positive against the intercellular cement of the stratified epithelium from monkey esophagus. We hypothesize that COVID-19 stimulated the release of multiple pemphigus antigens, which resulted in the unusual histologic pattern reported in the present case. Although malignancy should be suspected when features of paraneoplastic pemphigus, such as basement membrane staining on direct immunofluorescence, are noted, it may also be a histologic pattern of pemphigus secondary to COVID-19 that clinicians may consider.
PubMed: 38371950
DOI: 10.1177/2050313X241231423 -
Cell & Bioscience Feb 2024Patients with cirrhosis have intestinal barrier dysfunction but the role of the individual cell types in human small intestine is unclear. We performed single-nuclear...
Patients with cirrhosis have intestinal barrier dysfunction but the role of the individual cell types in human small intestine is unclear. We performed single-nuclear RNA sequencing (snRNAseq) in the pinch biopsies of terminal ileum of four age-matched men [56 years, healthy control, compensated, early (ascites and lactulose use) and advanced decompensated cirrhosis (ascites and rifaximin use)]. Cell type proportions, differential gene expressions, cell-type specific pathway analysis using IPA, and cellular crosstalk dynamics were compared. Stem cells, enterocytes and Paneth cells were lowest in advanced decompensation. Immune cells like naive CD4 + T cells were lowest while ITGAE + cells were highest in advanced decompensation patients. MECOM had lowest expression in stem cells in advanced decompensation. Defensin and mucin sulfation gene (PAPSS2) which can stabilize the mucus barrier expression were lowest while IL1, IL6 and TNF-related genes were significantly upregulated in the enterocytes, goblet, and Paneth cells in decompensated subjects. IPA analysis showed higher inflammatory pathways in enterocytes, stem, goblet, and Paneth cells in decompensated patients. Cellular crosstalk analysis showed that desmosome, protease-activated receptors, and cadherin-catenin complex interactions were most perturbed in decompensated patients. In summary, the snRNAseq of the human terminal ileum in 4 subjects (1 control and three cirrhosis) identified multidimensional alteration in the intestinal barrier with lower stem cells and altered gene expression focused on inflammation, mucin sulfation and cell-cell interactions with cirrhosis decompensation.
PubMed: 38369527
DOI: 10.1186/s13578-024-01209-5 -
Molecular & Cellular Proteomics : MCP Mar 2024Desmosomes are multiprotein adhesion complexes that link intermediate filaments to the plasma membrane, ensuring the mechanical integrity of cells across tissues, but...
Desmosomes are multiprotein adhesion complexes that link intermediate filaments to the plasma membrane, ensuring the mechanical integrity of cells across tissues, but how they participate in the wider signaling network to exert their full function is unclear. To investigate this, we carried out protein proximity mapping using biotinylation (BioID). The combined interactomes of the essential desmosomal proteins desmocollin 2a, plakoglobin, and plakophilin 2a (Pkp2a) in Madin-Darby canine kidney epithelial cells were mapped and their differences and commonalities characterized as desmosome matured from Ca dependence to the mature, Ca-independent, hyper-adhesive state, which predominates in tissues. Results suggest that individual desmosomal proteins have distinct roles in connecting to cellular signaling pathways and that these roles alter substantially when cells change their adhesion state. The data provide further support for a dualistic concept of desmosomes in which the properties of Pkp2a differ from those of the other, more stable proteins. This body of data provides an invaluable resource for the analysis of desmosome function.
Topics: Animals; Dogs; Desmosomes; Cell Membrane; Plakophilins; Madin Darby Canine Kidney Cells; Signal Transduction; Cell Adhesion; Desmoplakins
PubMed: 38342409
DOI: 10.1016/j.mcpro.2024.100735 -
Diagnostics (Basel, Switzerland) Jan 2024Arrhythmogenic cardiomyopathy is a primary genetic disease caused by mutations in the desmosome genes. Ever since the introduction of new imaging techniques, like...
Arrhythmogenic cardiomyopathy is a primary genetic disease caused by mutations in the desmosome genes. Ever since the introduction of new imaging techniques, like cardiovascular magnetic resonance, the diagnosis of arrhythmogenic cardiomyopathy has become more challenging as left ventricular or biventricular variants may have resemblance to other cardiomyopathies or myocarditis. Not only this but they may also share an acute phase, which might cause even more confusion and misdiagnoses and influence the prognosis and outcome. In this case report, we present a 31-year-old patient with multiple clinical pictures: his symptoms were acute chest pain, new onset of heart failure and arrhythmia symptoms, which determined a dynamic change in clinical diagnosis and management, ultimately taking into consideration arrhythmogenic cardiomyopathy. Through the article, we try to uncover and explain common pathophysiological pathways shared by arrhythmogenic cardiomyopathy and other clinical entities with a special focus on inflammation. The final question remains:
PubMed: 38337764
DOI: 10.3390/diagnostics14030248 -
Scientific Reports Jan 2024The cardiac muscle consists of individual cardiomyocytes that are mechanically linked by desmosomes. Desmosomal adhesion is mediated by densely packed and organized...
The cardiac muscle consists of individual cardiomyocytes that are mechanically linked by desmosomes. Desmosomal adhesion is mediated by densely packed and organized cadherins which, in presence of Ca, stretch out their extracellular domains (EC) and dimerize with opposing binding partners by exchanging an N-terminal tryptophan. The strand-swap binding motif of cardiac cadherins like desmocollin 2 (Dsc2) (and desmoglein2 alike) is highly specific but of low affinity with average bond lifetimes in the range of approximately 0.3 s. Notably, despite this comparatively weak interaction, desmosomes mediate a stable, tensile-resistant bond. In addition, force mediated dissociation of strand-swap dimers exhibit a reduced bond lifetime as external forces increase (slip bond). Using atomic force microscopy based single molecule force spectroscopy (AFM-SMFS), we demonstrate that Dsc2 has two further binding modes that, in addition to strand-swap dimers, most likely play a significant role in the integrity of the cardiac muscle. At short interaction times, the Dsc2 monomers associate only loosely, as can be seen from short-lived force-independent bonds. These ideal bonds are a precursor state and probably stabilize the formation of the self-inhibiting strand-swap dimer. The addition of tryptophan in the measurement buffer acts as a competitive inhibitor, preventing the N-terminal strand exchange. Here, Dsc2 dimerizes as X-dimer which clearly shows a tri-phasic slip-catch-slip type of dissociation. Within the force-mediated transition (catch) regime, Dsc2 dimers switch between a rather brittle low force and a strengthened high force adhesion state. As a result, we can assume that desmosomal adhesion is mediated not only by strand-swap dimers (slip) but also by their precursor states (ideal bond) and force-activated X-dimers (catch bond).
Topics: Protein Binding; Tryptophan; Cadherins; Dimerization; Physical Phenomena; Cell Adhesion
PubMed: 38297017
DOI: 10.1038/s41598-024-52725-w -
Journal of Experimental & Clinical... Jan 2024Cadherin-17 (CDH17), a marker of differentiation in intestinal cells, binds and activates α2β1 integrin to promote cell adhesion and proliferation in colorectal cancer...
BACKGROUND
Cadherin-17 (CDH17), a marker of differentiation in intestinal cells, binds and activates α2β1 integrin to promote cell adhesion and proliferation in colorectal cancer (CRC) metastasis. Furthermore, CDH17 associates with p120- and β-catenin in a manner yet to be fully elucidated. In this report, we explored the molecular mediators involved in this association, their contribution to CRC dissemination and potential therapeutic implications.
METHODS
Proteomic and confocal analyses were employed to identify and validate CDH17 interactors. Functional characterization involved the study of proliferation, migration, and invasion in cell lines representative of various phenotypes. Immunohistochemistry was conducted on CRC tissue microarrays (TMA). In vivo animal experiments were carried out for metastatic studies.
RESULTS
We found that desmocollin-1 (DSC1), a desmosomal cadherin, interacts with CDH17 via its extracellular domain. DSC1 depletion led to increased or decreased invasion in CRC cells displaying epithelial or mesenchymal phenotype, respectively, in a process mediated by the association with p120-catenin. Down-regulation of DSC1 resulted in an increased expression of p120-catenin isoform 1 in epithelial cells or a shift in cellular location in mesenchymal cells. Opposite results were observed after forced expression of CDH17. DSC1 is highly expressed in budding cells at the leading edge of the tumor and associates with poor prognosis in the stem-like, mesenchymal CRC subtypes, while correlates with a more favorable prognosis in the less-aggressive subtypes. In vivo experiments demonstrated that DSC1 silencing reduced tumor growth, liver homing, and metastasis in CRC mesenchymal cells. Furthermore, a synthetic peptide derived from CDH17, containing the NLV motif, effectively inhibited invasion and liver homing in vivo, opening up new possibilities for the development of novel therapies focused on desmosomal cadherins.
CONCLUSIONS
These findings shed light on the multifaceted roles of CDH17, DSC1, and p120-catenin in CRC metastasis, offering insights into potential therapeutic interventions for targeting desmosomal cadherins in poorly-differentiated carcinomas.
Topics: Animals; Desmocollins; Delta Catenin; Proteomics; Cadherins; Colorectal Neoplasms
PubMed: 38263178
DOI: 10.1186/s13046-024-02956-6 -
Frontiers in Medicine 2023Pemphigus is a life-threatening autoimmune blistering disease affecting skin and mucous membranes. Despite its etiopathogenesis remains largely unknown, several trigger... (Review)
Review
Pemphigus is a life-threatening autoimmune blistering disease affecting skin and mucous membranes. Despite its etiopathogenesis remains largely unknown, several trigger and predisposing factors have been reported. Pemphigus is caused by autoantibodies that target desmoglein 1 and desmoglein 3, impacting desmosome function. However, circulating autoantibodies are often the consequence of a precipitating factor that occurs in predisposed individuals. This review aims to describe and discuss almost all trigger and predisposing factors reported as possible or probable cause of the disease. Among the reported trigger factors that may induce or exacerbate pemphigus, we have found of particular interest: drug intake (especially thiol- and phenol-containing compounds), vaccines, infections, as well as some reports about pregnancy, radiations, emotional stress, pesticides and physical trauma. Moreover, we discuss the possible role of food intake in pemphigus onset and particular attention is given to dietary factors containing thiol, phenol and tannin compounds. A trigger factor is "the straw that breaks the camel's back," and often acts together with predisposing factors. Here we discuss how pemphigus onset may be influenced by genetic susceptibility and comorbidities like thyroid diseases, malignancies and other autoimmune disorders. To identify other hitherto unknown trigger and predisposing factors, well designed prospective studies are needed. In this context, future research should explore their connection with the aim to advance our understanding of pemphigus pathogenesis.
PubMed: 38213911
DOI: 10.3389/fmed.2023.1326359 -
International Journal of Molecular... Dec 2023Desmosomes are essential structures for ensuring tissue functions, and their deregulation is involved in the development of colorectal cancer (CRC). JUP (γ-catenin) is...
Desmosomes are essential structures for ensuring tissue functions, and their deregulation is involved in the development of colorectal cancer (CRC). JUP (γ-catenin) is a desmosome adhesion component that also acts as a signaling hub, suggesting its potential involvement in CRC progression. In this context, we recently demonstrated that miR-195-5p regulated JUP and desmosome cadherins expression. In addition, miR-195-5p gain of function indirectly modulated the expression of key effectors of the Wnt pathway involved in JUP-dependent signaling. Here, our purpose was to demonstrate the aberrant expression of miR-195-5p and JUP in CRC patients and to functionally characterize the role of miR-195-5p in the regulation of desmosome function. First, we showed that miR-195-5p was downregulated in CRC tumors compared to adjacent normal tissue. Then, we demonstrated that JUP expression was significantly increased in CRC tissues compared to adjacent normal tissues. The effects of miR-195-5p on CRC progression were assessed using in vitro transient transfection experiments and in vivo miRNA administration. Increased miR-195-5p in colonic epithelial cells strongly inhibits cell proliferation, viability, and invasion via JUP. In vivo gain of function of miR-195-5p reduced the numbers and sizes of tumors and significantly ameliorated the histopathological changes typical of CRC. In conclusion, our findings indicate a potential pharmacological target based on miR-195-5p replacement as a new therapeutic approach in CRC.
Topics: Humans; Desmosomes; gamma Catenin; Down-Regulation; Colonic Neoplasms; MicroRNAs
PubMed: 38203664
DOI: 10.3390/ijms25010494 -
International Journal of Molecular... Dec 2023The epidermis serves many vital roles, including protecting the body from external influences and healing eventual injuries. It is maintained by an incredibly complex... (Review)
Review
The epidermis serves many vital roles, including protecting the body from external influences and healing eventual injuries. It is maintained by an incredibly complex and perfectly coordinated keratinization process. In this process, desquamation is essential for the differentiation of epidermal basal progenitor cells into enucleated corneocytes, which subsequently desquamate through programmed death. Numerous factors control keratinocyte differentiation: epidermal growth factor, transforming growth factor-α, keratinocyte growth factor, interleukins IL-1-β and IL-6, elevated vitamin A levels, and changes in Ca concentration. The backbone of the keratinocyte transformation process from mitotically active basal cells into fully differentiated, enucleated corneocytes is the expression of specific proteins and the creation of a Ca and pH gradient at precise locations within the epidermis. Skin keratinization disorders (histologically characterized predominantly by dyskeratosis, parakeratosis, and hyperkeratosis) may be categorized into three groups: defects in the α-helical rod pattern, defects outside the α-helical rod domain, and disorders of keratin-associated proteins. Understanding the process of keratinization is essential for the pathogenesis of many dermatological diseases because improper desquamation and epidermopoiesis/keratinization (due to genetic mutations of factors or due to immune pathological processes) can lead to various conditions (ichthyoses, palmoplantar keratodermas, psoriasis, pityriasis rubra pilaris, epidermolytic hyperkeratosis, and others).
Topics: Humans; Skin; Epidermis; Cell Differentiation; Keratinocytes; Psoriasis
PubMed: 38203406
DOI: 10.3390/ijms25010236