ABSTRACT
The roles of the gap junction protein connexin31.1 (Cx31.1) are poorly understood, especially as the protein appears to form non-functional channels. Cx31.1 specific antisense oligodeoxynucleotides (ODNs) were designed to evaluate its roles in a corneal epithelium model. Expression of Cx31.1 in corneal epithelium extends from the suprabasal layers of polyhedral wing cells through to the flat squamous cells of superficial layers which are shed into the tear film. Deoxyribozymes (Dzs) were tested for cleavage efficacy using in vitro transcribed Cx31.1 mRNA. Cleavage results showed a putative tertiary structure for Cx31.1 mRNA with one region appearing to have a higher potential for antisense targeting. Application of antisense ODNs designed to this region caused Cx31.1 knockdown in rat and human corneal organotypic culture models, leading to a reduction in apoptosis and a thickening of the corneal epithelium (p=0.0045). Cx31.1 appears to play a role in triggering cell death; knocking it down may provide a novel approach for tissue repair and engineering.
Subject(s)
Apoptosis , Connexins/antagonists & inhibitors , Epithelium, Corneal/metabolism , Oligonucleotides, Antisense , Animals , Base Sequence , Connexins/genetics , Connexins/metabolism , DNA, Catalytic/metabolism , Down-Regulation , Epithelium, Corneal/anatomy & histology , Gene Knockdown Techniques , Humans , Mice , Rats , Time FactorsABSTRACT
A bi-enzyme-based Clark electrode was developed for the determination of 3-hydroxybutyrate. This sensor is based on the specific dehydrogenation by 3-hydroxybutyrate dehydrogenase (HBDH, E.C. 1.1.1.30) in combination with salicylate hydroxylase (SHL E.C. 1.14.13.1). The enzymes were entrapped by a poly(carbamoyl) sulfonate (PCS) hydrogel on a Teflon membrane. The principle of the determination scheme is as follows: the specific detecting enzyme, HBDH, catalyses the specific dehydrogenation of 3-hydroxybutyrate consuming NAD(+). The products, NADH, initiate the irreversible decarboxylation and the hydroxylation of salicylate by SHL in the presence of oxygen. SHL forces the equilibrium of dehydrogenation of 3-hydroxybutyrate by HBDH to the product side by consuming NADH. Dissolved oxygen acts as an essential material for SHL during its enzymatic reactions. This results in a detectable signal due to the SHL-enzymatic consumptions of dissolved oxygen in the measurement of 3-hydroxybutyrate. Interferences from different amino acids and electroactive substances were found to be minimal due to the specificity of HBDH and the application of a Teflon membrane. The sensor has a fast response (2s) and short recovery time (2 min) with a linear range between 8 and 800 microM 3-hydroxybutyrate and a detection limit of 3.9 microM. A good agreement (R(2)=0.9925) with theoretical calculation was obtained in spiked serum sample measurements.
Subject(s)
3-Hydroxybutyric Acid/blood , 3-Hydroxybutyric Acid/chemistry , Biosensing Techniques/instrumentation , Electrochemistry/instrumentation , Hydroxybutyrate Dehydrogenase/chemistry , Mixed Function Oxygenases/chemistry , Transducers , Biosensing Techniques/methods , Blood Chemical Analysis/instrumentation , Blood Chemical Analysis/methods , Electrochemistry/methods , Equipment Design , Equipment Failure Analysis , Humans , Reproducibility of Results , Sensitivity and SpecificitySubject(s)
Connexins/deficiency , Connexins/genetics , Oligonucleotides, Antisense/genetics , Animals , Brain/metabolism , Chick Embryo , Connexins/antagonists & inhibitors , Gels , Gene Expression Regulation, Developmental , Gene Targeting , In Vitro Techniques , Oligonucleotides, Antisense/pharmacology , Poloxamer , Rats , Surface-Active AgentsABSTRACT
The purpose of this study was to demonstrate the presence of vinculin and alpha 2 integrin in chondrocytes in situ and epithelial cells. We also determined that the appropriate fixation and extraction protocols for immunohistochemistry and laser scanning confocal microscopy for an integral membrane protein and an actin-associated protein in cultured cells and whole tissue was different. Cultured epithelial cells, whole mount human cornea and avian cartilage were fixed and prepared using a number of standard procedures used for indirect fluorescence immunohistochemistry. The distribution of vinculin was cell-type and fixation-specific. Chondrocytes and cultured epithelial cells demonstrated vinculin in areas that appear to be associated with filamentous actin. Vinculin was associated with cell membranes in human cornea. The expression of alpha 2 integrin observed in chondrocytes fixed with methanol, paraformaldehyde, or formaldehyde is consistent with its role in cell-substrate interaction, but may also suggest a role in dividing and differentiating cells. The localization of alpha 2 integrin in human corneal epithelia supports its role as a cell-cell adhesion molecule. The cytoplasmic distribution of vinculin and alpha 2 integrin in tissues fixed without detergent extraction suggests that the fixation step may be sufficient for antibody penetration and antigen extraction. These studies are the first report of vinculin and alpha 2 integrin in embryonic chondrocytes. In addition we have shown that confocal laser scanning microscopy combined with proper fixation and extraction protocols may optimize the localization of antigens in cultured and whole mount cells.
