scholarly journals Deciphering the mechanoresponsive role of β-catenin in keratoconus epithelium

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chatterjee Amit ◽  
Prema Padmanabhan ◽  
Janakiraman Narayanan
Keyword(s):  
Corneal Epithelium ◽  
Refractive Surgery ◽  
Structural Changes ◽  
Corneal Transplantation ◽  
Corneal Stroma ◽  
Corneal Dystrophy ◽  
Collagen Crosslinking ◽  
Immunofluorescence Studies ◽  
Ultrastructural Characteristics

AbstractKeratoconus (KC) is a corneal dystrophy characterized by progressive ectasia that leads to severe visual impairment and remains one of the leading indications for corneal transplantation. The etiology is believed to be multifactorial and alterations have been documented in the biomechanical, biochemical and ultrastructural characteristics of the cornea. While the exact site of disease origin is still debated, changes in the corneal epithelium are believed to occur even before the disease is clinically manifested. In this study we investigate the possible role of β-catenin as mechanotransducer in KC corneal epithelium. The sheets of corneal epithelium removed from keratoconic eyes when they underwent collagen crosslinking as a therapeutic procedure were used for this study. The healthy corneal epithelium of patients undergoing Laser Refractive Surgery for the correction of their refractive error, served as controls. Immunoblotting and tissue immunofluorescence studies were performed on KC epithelium to analyse the expression and localization of β-catenin, E-cadherin, ZO1, α-catenin, Cyclin D1, α-actinin, RhoA, and Rac123. Co-immunoprecipitation of β-catenin followed by mass spectrometry of KC epithelium was performed to identify its interacting partners. This was further validated by using epithelial tissues grown on scaffolds of different stiffness. Histology data reported breaks in the Bowman’s layer in KC patients. We hypothesize that these breaks expose the epithelium to the keratoconic corneal stroma, which, is known to have a decreased elastic modulus and that β-catenin acts as a mechanotransducer that induces structural changes such as loss of polarity (Syntaxin3) and barrier function (ZO1) through membrane delocalization. The results of our study strongly suggest that β-catenin could be a putative mechanotransducer in KC epithelium, thus supporting our hypothesis.

scholarly journals Deciphering the mechanoresponsive role of β-catenin in Keratoconus epithelium

2019 ◽  
Author(s):  
Chatterjee Amit ◽  
Prema Padmanabhan ◽  
Janakiraman Narayanan
Keyword(s):  
Cyclin D1 ◽  
Corneal Epithelium ◽  
Cell Adhesion Molecule ◽  
Corneal Stroma ◽  
Substrate Stiffness ◽  
Lipid Transfer ◽  
Immunofluorescence Studies ◽  
E Cadherin

AbstractKeratoconus (KC) a disease with established biomechanical instability of the corneal stroma, is an ideal platform to identify key proteins involved in mechanosensing. This study aims to investigate the possible role of β-catenin as mechanotransducer in KC epithelium. KC patients were graded as mild, moderate or severe using Amsler Krumeich classification. Immunoblotting and tissue immunofluorescence studies were performed on KC epithelium to analyze the expression and localization of β-catenin, E-cadherin, ZO1, α-catenin, Cyclin D1, α-actinin, RhoA, Rac123. Co-immunoprecipitation (Co-IP) of β-catenin followed by mass spectrometry of mild KC epithelium was performed to identify its interacting partners. This was further validated by using epithelial tissues grown on scaffolds of different stiffness. We observed down regulation of E-cadherin, α-catenin, ZO1 and upregulation of Cyclin D1, α-actinin and RhoA in KC corneal epithelium. β-catenin Co-IP from mild KC epithelium identified new interacting partners such as StAR-related lipid transfer protein3, Dynamin-1-like protein, Cardiotrophin-1,Musculin, Basal cell adhesion molecule and Protocadherin Fat 1.β-catenin localization was altered in KC which was validatedin vitro, using control corneal epithelium grown on different substrate stiffness. β-catenin localization is dependent upon the elastic modulus of the substrate and acts as mechanotransducer by altering its interaction and regulating the barrier function in corneal epithelium.

scholarly journals Impairment of the autophagy-lysosomal pathway and activation of pyroptosis in macular corneal dystrophy

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Tao Zheng ◽  
Chuchu Zhao ◽  
Baowen Zhao ◽  
Hanruo Liu ◽  
Shijian Wang ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Periodic Acid ◽  
Corneal Transplantation ◽  
Corneal Stroma ◽  
Keratan Sulfate ◽  
Corneal Dystrophy ◽  
Autophagic Flux ◽  
Periodic Acid Schiff ◽  
Caspase 1 ◽  
Macular Corneal Dystrophy

Abstract Macular corneal dystrophy (MCD) is ascribed to mutations in the carbohydrate sulfotransferase (CHST6) gene affecting keratan sulfate (KS) hydrophilicity and causing non-sulfated KS to precipitate in keratocytes and the corneal stroma. We investigated roles for inflammatory responses in MCD pathogenesis by examining the lysosomal-autophagy pathway and activation of pyroptosis in MCD keratocytes. Normal and lesioned keratocytes were obtained from MCD patients undergoing corneal transplantation. The keratocytes were subjected to gene sequencing, RT-PCR, western blotting, transmission electron microscopy, histological staining, induction and inhibition assays of autophagy and pyroptosis, CCK-8 and LysoTracker Green DND-26 labeling, and flow cytometry. A novel homozygous MCD mutation was identified in a family from Northeast China; the mutation was distinguished by cytoplasmic vacuolation, cell membrane disruption, electron dense deposits, and deposition of a band of Periodic acid-Schiff and Alcian blue-positive material in the keratocytes and stroma layer. KS protein levels were decreased, expression of p62 and LC3-II proteins was enhanced, cathepsin D expression was declined and the LysoTracker Green DND-26 signal was dramatically reduced in MCD keratocytes. Bafilomycin-A1 treatment significantly increased caspase-1 and Pro-IL-1β expression in normal and MCD keratocytes. Nod-like receptors pyrins-3 (NLRP3), caspase-1, Pro-IL-1β, and IL-1β levels were pronouncedly elevated in cells exposed to H2O2. Ac-YVAD-CMK treatment reversed this expression in normal and MCD keratocytes. Suppression of the autophagic degradation of non-sulfated KS by impaired autophagic flux in MCD keratocytes triggers pyroptosis. Amelioration of impaired autophagy and restraint of pyroptosis may, therefore, have therapeutic efficacy in the treatment of MCD.

Economic Growth: New Problems and New Risks

2006 ◽  
pp. 20-37 ◽  
Author(s):  
M. Ershov
Keyword(s):  
Economic Growth ◽  
Foreign Exchange ◽  
Driving Force ◽  
Structural Changes ◽  
Rate Of Growth

The economic growth, which is underway in Russia, raises new questions to be addressed. How to improve the quality of growth, increasing the role of new competitive sectors and transforming them into the driving force of growth? How can progressive structural changes be implemented without hampering the rate of growth in general? What are the main external and internal risks, which may undermine positive trends of development? The author looks upon financial, monetary and foreign exchange aspects of the problem and comes up with some suggestions on how to make growth more competitive and sustainable.

Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

2019 ◽  
Vol 12 (4) ◽  
pp. 311-323 ◽  
Author(s):  
Salvatore Benvenga ◽  
Antonio Micali ◽  
Giovanni Pallio ◽  
Roberto Vita ◽  
Consuelo Malta ◽  
...  
Keyword(s):  
Structural Changes ◽  
Natural Antioxidants ◽  
Minor Role ◽  
Positive Role ◽  
Testosterone Levels ◽  
Tnf Α ◽  
Testicular Lesions ◽  
A Minor ◽  
Immunohistochemical Analyses

Background: Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier. Objective: As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes. Methods: Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses. Results: CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number. Conclusion: We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

Autosomal recessive congenital hereditary corneal dystrophy associated with a novel SLC4A11 mutation in two consanguineous Tunisian families

2021 ◽  
pp. bjophthalmol-2020-318204
Author(s):  
Zohra Chibani ◽  
Imen Zone Abid ◽  
Peter Söderkvist ◽  
Jamel Feki ◽  
Mounira Hmani Aifa
Keyword(s):  
Autosomal Recessive ◽  
Corneal Transplantation ◽  
Gene Mutations ◽  
In Silico Analysis ◽  
Corneal Dystrophy ◽  
Solute Carrier Family ◽  
Transporter Protein ◽  
Bicarbonate Transporter ◽  
Corneal Clouding ◽  
Solute Carrier

BackgroundAutosomal recessive congenital hereditary corneal dystrophy (CHED) is a rare isolated developmental anomaly of the eye characterised by diffuse bilateral corneal clouding that may lead to visual impairment requiring corneal transplantation. CHED is known to be caused by mutations in the solute carrier family 4 member 11 (SLC4A11) gene which encodes a membrane transporter protein (sodium bicarbonate transporter-like solute carrier family 4 member 11).MethodsTo identify SLC4A11 gene mutations associated with CHED (OMIM: #217700), genomic DNA was extracted from whole blood and sequenced for all exons and intron-exon boundaries in two large Tunisian families.ResultsA novel deletion SLC4A11 mutation (p. Leu479del; c.1434_1436del) is responsible for CHED in both analysed families. This non-frameshift mutation was found in a homozygous state in affected members and heterozygous in non-affected members. In silico analysis largely support the pathogenicity of this alteration that may leads to stromal oedema by disrupting the osmolarity balance. Being localised to a region of alpha-helical secondary structure, Leu479 deletion may induce protein-compromising structural rearrangements.ConclusionTo the best of our knowledge, this is the first clinical and genetic study exploring CHED in Tunisia. The present work also expands the list of pathogenic genotypes in SLC4A11 gene and its associated clinical diagnosis giving more insights into genotype–phenotype correlations.

scholarly journals Exploring Mucin as Adjunct to Phage Therapy

2021 ◽  
Vol 9 (3) ◽  
pp. 509
Author(s):  
Amanda Carroll-Portillo ◽  
Henry C. Lin
Keyword(s):  
Pathogenic Bacteria ◽  
Structural Changes ◽  
Phage Therapy ◽  
Bacterial Species ◽  
Gi Tract ◽  
Beneficial Bacteria ◽  
Phage Cocktail ◽  
Small Intestinal ◽  
Gastrointestinal Dysbiosis

Conventional phage therapy using bacteriophages (phages) for specific targeting of pathogenic bacteria is not always useful as a therapeutic for gastrointestinal (GI) dysfunction. Complex dysbiotic GI disorders such as small intestinal bowel overgrowth (SIBO), ulcerative colitis (UC), or Crohn’s disease (CD) are even more difficult to treat as these conditions have shifts in multiple populations of bacteria within the microbiome. Such community-level structural changes in the gut microbiota may require an alternative to conventional phage therapy such as fecal virome transfer or a phage cocktail capable of targeting multiple bacterial species. Additionally, manipulation of the GI microenvironment may enhance beneficial bacteria–phage interactions during treatment. Mucin, produced along the entire length of the GI tract to protect the underlying mucosa, is a prominent contributor to the GI microenvironment and may facilitate bacteria–phage interactions in multiple ways, potentially serving as an adjunct during phage therapy. In this review, we will describe what is known about the role of mucin within the GI tract and how its facilitation of bacteria–phage interactions should be considered in any effort directed at optimizing effectiveness of a phage therapy for gastrointestinal dysbiosis.

scholarly journals Structural and Technological Approach to Reveal the Role of the Lipid Phase in the Formation of Soy Emulsion Gels with Chia Oil

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 48
Author(s):  
Ana M. Herrero ◽  
Claudia Ruiz-Capillas
Keyword(s):  
Raman Spectroscopy ◽  
Structural Properties ◽  
Structural Changes ◽  
Protein Secondary Structure ◽  
Lipid Phase ◽  
Α Helix ◽  
Β Sheet ◽  
Shed Light ◽  
Chia Oil

Considerable attention has been paid to emulsion gels (EGs) in recent years due to their interesting applications in food. The aim of this work is to shed light on the role played by chia oil in the technological and structural properties of EGs made from soy protein isolates (SPI) and alginate. Two systems were studied: oil-free SPI gels (SPI/G) and the corresponding SPI EGs (SPI/EG) that contain chia oil. The proximate composition, technological properties (syneresis, pH, color and texture) and structural properties using Raman spectroscopy were determined for SPI/G and SPI/EG. No noticeable (p > 0.05) syneresis was observed in either sample. The pH values were similar (p > 0.05) for SPI/G and SPI/EG, but their texture and color differed significantly depending on the presence of chia oil. SPI/EG featured significantly lower redness and more lightness and yellowness and exhibited greater puncture and gel strengths than SPI/G. Raman spectroscopy revealed significant changes in the protein secondary structure, i.e., higher (p < 0.05) α-helix and lower (p < 0.05) β-sheet, turn and unordered structures, after the incorporation of chia oil to form the corresponding SPI/EG. Apparently, there is a correlation between these structural changes and the textural modifications observed.

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