Effects of UVR and UVR-induced Cytokines on Production of Extracellular Matrix Proteins and Proteases by Dermal Fibroblasts Cultured in Collagen Gels¶

Ultraviolet-B radiation induces transcriptional modulation of components associated with the extracellular matrix in embryos of decapod Macrobrachium olfersii

The extracellular matrix (ECM) is a non-cellular and three-dimensional structure, constituted by a macromolecular dynamic network that involves the cells in all animal tissues, including embryonic ones. Several studies with vertebrates and cell cultures have reported deleterious effects of ultraviolet-B (UVB) radiation on the components associated with the ECM. However, studies focusing on the UVB radiation effects on ECM components of crustaceans during embryonic development are very scarce. Thus, the aim of this study was to identify the coding sequences of components associated with the ECM and to evaluate the effect of UVB radiation on embryos of the ecologically-important decapod Macrobrachium olfersii. To evaluate the modulation of these ECM components during embryonic development, the transcript levels of Col4α1, Itgβ, Lamα, Mmp1 and Timp in M. olfersii embryos were analyzed at early developmental stages (E1, E3 and E4), intermediate developmental stage (E7) and late developmental stages (E10 and E14). In addition, embryos at E7, which correspond to a landmark of crustacean development, were analyzed after 12 h of UVB exposure to verify UVB effects on the ECM components. The ECM component sequences were similar to other decapods, suggesting conservation of these genes among crustaceans. The results showed modulations of the ECM components of M. olfersii embryos that reflect the need for each component in the cellular mechanisms, necessary for normal embryonic development. After UVB exposure, embryos showed opacity of embryonic tissues and it was found the overexpression of Col4α1, Itgβ, Mmp1 and Timp transcript levels (1.82-, 1.52-, 2.34- and 6.27-fold, respectively). These impairments can compromise important events for normal embryonic development, such as growth of optic lobes, caudal papilla, ramification of appendages and differentiation of organic systems. The results presented here, together with the effects on morphology, cell proliferation, differentiation, and apoptosis demonstrated previously, strengthen the knowledge of the complex impacts of UVB radiation on freshwater embryos. Nevertheless, our results encourage further investigations focusing on the assessment of UVB effects on different organisms in order to better understand the myriad of UVB effects on ECM components.

Zymographic and ultrastructural evaluations after low-level laser irradiation on masseter muscle of HRS/J strain mice

Low-level laser therapy (LLLT) has been widely used in the treatment of the stomatognathic system dysfunction; however, its biological effect remains poorly understood. This study evaluated the effect of LLLT (GaAlAs, 780 nm, 20 J/cm(2), 40 mW) on masseter muscle of HRS/J mice after different numbers of laser irradiations (three, six, and ten) for 20 s in alternate days. Three experimental groups were defined according to the number of laser irradiations and three control groups (n=5) were used. On the third day after the last irradiation, all animals were killed and the masseter muscle was removed and processed for the following analysis: (a) transmission electron microscopy, (b) zymography, (c) immunohistochemistry for vascular endothelial growth factor (VEGF) and VEGFR-2. The results showed: (a) with six laser applications, a dilation of T tubules, and sarcoplasmic reticulum cistern, increased pinocytosed vesicles in the endothelium; with ten laser applications, few pinocytic vesicles in the endothelium and condensed mitochondria. (b) Under the conditions of this study, the synthesis of other matrix metalloproteinases was not observed, only the MMP-2 and -9. (c) After ten laser irradiations, immunostaining was observed only for VEGFR-2. We conclude that after six laser applications, ultrastructural changes may facilitate the Ca(+2) transfer to cytosol and increase the fluid transport from one surface to another. The ultrastructural changes and no immunostaining for VEGF with ten applications may decrease the metabolic activity as well as damage the angiogenic process, suggesting that an effective number of laser applications may be less than ten, associating to this therapy a better cost-benefit.

Manipulation of living cells by using PC-controlled micro-pattern projection system

In order to meet the diversifying demand for the cell manipulation in the rapid progress of cell engineering, we developed a novel technique to capture the living cells on a culture substrate by irradiating light in a multiple manner. In clear contrast to the conventional cell patterning using the previously patterned substrate, the cell-retaining area can be defined even after cell seeding, and the captured cells can continue to grow freely beyond the defined area afterwards. After the light irradiation in arbitrary micropattern by using a newly developed apparatus and the process to remove non-captured cells including EDTA treatment, the highly contrasted cell patterns were formed with the precision of single cell size. Moreover, it was determined that the cell capturing arose just after light irradiation and diminished gradually in a time scale of 10h. It was confirmed that the cells maintained their viability well after the manipulation process including photo-induced cell capturing.

Involvement of UVB-induced reactive oxygen species in TGF-beta biosynthesis and activation in keratinocytes

TGF-beta produced by keratinocytes in response to UVB (290-320 nm) is a potential mediator for effects of acute and chronic solar radiation on skin. This study was designed to determine whether reactive oxygen species (ROS) mediate UVB-induced TGF-beta biosynthesis in keratinocytes and the subsequent activation of the latent TGF-beta complex. UVB irradiation elevated both total (latent plus active) and active TGF-beta in the keratinocyte supernatants, with a greater increase in the active form. UVB irradiation induced up to a 30% increase in ROS, and the ROS were detected up to 90 min after irradiation. NAC and Trolox, cytoplasmic ROS scavengers, abolished the UVB-induced TGF-beta and intracellular ROS, suggesting that UVB-induced ROS are involved in TGF-beta regulation. Inhibitors of NADPH oxidase activity, DPI and apocynin, decreased UVB-induced ROS. The increase in NADPH oxidase activity was mediated by EGFR activation. UVB-induced ROS also activated latent TGF-beta complex by stimulating MMP-2 and -9 activities. In summary, physiological doses of UVB increase intracellular ROS, which upregulate TGF-beta biosynthesis and activation of TGF-beta through increased activity of MMPs.