Air Particulate Matter Induces Skin Barrier Dysfunction and Water Transport Alteration on a Reconstructed Human Epidermis Model.

Knowing the damage that particulate matter (PM) can cause in skin is important for tightly controlling the release of air pollutants and preventing more serious diseases. This study investigates if such alterations are present in reconstructed human epidermis exposed to coarse air PM. Exposure of reconstructed human epidermis to increasing concentrations (2.2, 8.9, and 17.9 µg/cm2) of standard urban PM over time led to decreased cell viability at 48 hours. The barrier function was shown to be compromised by 24 hours of exposure to high doses (17.9 µg/cm2). Morphological alterations included cytoplasm vacuolization and partial loss of epidermal stratification. Cytokeratin 10, involucrin, loricrin, and filaggrin protein levels were significantly decreased. We confirmed an inflammatory process by IL-1α release and found a significant increase in AQP3 expression. We also demonstrated changes in NOTCH1 and AhR expression of epidermis treated with coarse air PM. The use of hydrogen peroxide altered AQP3 and NOTCH1 expression, and the use of N-acetyl-L-cysteine altered NOTCH1 expression, suggesting that this is a redox-dependent process. These results demonstrate that coarse air PM induces dose-dependent inflammatory response and alterations in protein markers of differentiation and water transport in the epidermis that could ultimately compromise the structural integrity of the skin, promoting or exacerbating various skin diseases.

Constructing and Validating 3D-pharmacophore Models to a Set of MMP-9 Inhibitors for Designing Novel Anti-melanoma Agents.

A receptor-independent (RI) four-dimensional structure-activity relationship (4D-QSAR) formalism was applied to a set of sixty-four ß-N-biaryl ether sulfonamide hydroxamate derivatives, previously reported as potent inhibitors against matrix metalloproteinase subtype 9 (MMP-9). MMP-9 belongs to a group of enzymes related to the cleavage of several extracellular matrix components and has been associated to cancer invasiveness/metastasis. The best RI 4D-QSAR model was statistically significant (N=47; r(2) =0.91; q(2) =0.83; LSE=0.09; LOF=0.35; outliers=0). Leave-N-out (LNO) and y-randomization approaches indicated the QSAR model was robust and presented no chance correlation, respectively. Furthermore, it also had good external predictability (82 %) regarding the test set (N=17). In addition, the grid cell occupancy descriptors (GCOD) of the predicted bioactive conformation for the most potent inhibitor were successfully interpreted when docked into the MMP-9 active site. The 3D-pharmacophore findings were used to predict novel ligands and exploit the MMP-9 calculated binding affinity through molecular docking procedure.

Predicting Novel Antitumor Agents: 3D-Pharmacophore Mapping of ß-N-biaryl Ether Sulfonamide-Based Hydroxamates as Potentially MMP-2 Inhibitors.

Matrix metalloproteinases (MMP) are a group of enzymes related to extracelular matrix remodeling. Some types of MMP are overexpressed by malignant tumors, mainly the MMP-2 subtype, and have been associated to cancer invasiveness and metastasis. A receptor-independent (RI) 4D-QSAR formalism was applied, herein, to a set of forty ß-N-biaryl ether sulfonamide hydroxamates, previously reported as potent MMP-2 inhibitors, in order to map 3D-pharmacophore models and predict novel antitumor agents. The best RI 4D-QSAR model was statistically significant (N=30, r(2) =0.93, q(2) =0.88, five occupancy descriptors (GCOD), LSE=0.04, LOF=0.11, outliers=0), robust and not obtained by chance. The external predictability was 75 % (test set; N=8). A different orientation (binding mode) in the MMP-2 catalytic site was suggested regarding the most hydrophobic portion (R1 ) of the compounds' structure. Compounds were predicted and their inhibitory activity against MMP-2 was calculated by using the optimum RI 4D-QSAR model. The findings have provided interesting information to drive the designing and synthesis of novel potentially MMP-2 inhibitors against melanoma invasion.