evaluation-keratinocyte-proliferation-on-two-three-dimensional-type-i

Evaluation of Keratinocyte Proliferation on Two- and Three-dimensional Type I Collagen Substrates

Type I collagen, useful as a substrate for cell culture, exists in two forms: the two-dimensional, non-fibrous form and three-dimensional, fibril form. ...

Nippi Research Institute of Biomatrix

Leather produced from crocodile, alligator, and caiman skin is widely used in the fashion industry. Crocodilian leather is generally more expensive than mammalian leather, and the value greatly differs even between the crocodilian species. However, inappropriate labeling of the animal source on leather products sometimes arises from accidental or fraudulent substitution, which is difficult to unambiguously detect by existing methods. In the present study, animal source identification of crocodilian leather was carried out using type I collagen-derived marker peptides generated after dechroming, heat denaturation, and trypsin digestion. Definitive discrimination between the three crocodilian species and also a related species, lizard, was achieved based on the detection patterns of selected six marker peptides, determined by LC-MS. Furthermore, powdering of the leather samples enabled a reduction in the sample amount required and allowed the elimination of the dechroming step. Approximately 100 μg of powder was taken from commercial leather watch straps by filing, resulting in only slight damage to the undersides of the straps. The animal sources of the crocodilian products and also a crocodile-embossed calf product were successfully identified using a combination of the crocodilian marker peptides and previously established mammalian marker peptides. This semi-nondestructive species identification method is not only useful for certification of leather products but also for monitoring of international trade of leather and skin.

Semi-Nondestructive Certification of Crocodilian Leather by LC-MS Detection of Collagen Marker Peptides.

Amylin and amyloid-β (Aβ) were found to induce reactive oxygen species (ROS) and reactive nitrogen species (RNS) in rat pancreatic β-cell line, INS-1 cells, leading to cell death. In this study, we report on reciprocal relationship between the expression of estrogen receptors (ERs) α and β (ERα and ERβ) and generation of ROS/RNS in amylin/Aβ -treated INS-1 cells. That is, pharmacological activation of ERs in INS-1 cells significantly decreases ROS/RNS generation, but blockage of ERs increases ROS/RNS generation. Silibinin is a natural polyphenolic flavonoid isolated from milk thistle with phytoestrogen activities, also known as silybin. Treatment with silibinin down-regulated ROS/RNS production induced by treatment with amylin/Aβ in the cells. Silencing ERs expression with siRNAs targeting ERs showed that the protective effect of silibinin was markedly weakened, indicating that silibinin protection is largely attributed to activation of ERs' signaling. The binding of silibinin to ERs implies that the protective effect of silibinin on amylin/Aβ -treated INS-1 cells owes to down-regulation of ROS/RNS through the activation of ERs phosphorylation. Amylin and Aβ cotreatment enhanced furthermore ROS/RNS generation and cytotoxicity through further down-regulation of ERs phosphorylation, and this was reversed by silibinin. Silibinin also protects INS-1 cells from amylin and Aβ cotreatment. These results indicate that protective effect of silibinin is mediated by enhancement of ERs phosphorylation that depresses ROS/RNS generation in amylin/Aβ -treated INS-1 cells.

Silibinin protects rat pancreatic β-cell through up-regulation of estrogen receptors' signaling against amylin- or Aβ -induced reactive oxygen species/reactive nitrogen species generation.

One of the morphological hallmarks of terminally differentiated secretory cells is highly proliferated membrane of the rough endoplasmic reticulum (ER), but the molecular basis for the high rate of protein biosynthesis in these cells remains poorly documented. An important aspect of ER translational control is the molecular mechanism that supports efficient use of targeted mRNAs in polyribosomes. Here, we identify an enhancement system for ER translation promoted by p180, an integral ER membrane protein we previously reported as an essential factor for the assembly of ER polyribosomes. We provide evidence that association of target mRNAs with p180 is critical for efficient translation, and that SF3b4, an RNA-binding protein in the splicing factor SF3b, functions as a cofactor for p180 at the ER and plays a key role in enhanced translation of secretory proteins. A -element in the 5' untranslated region of collagen and fibronectin genes is important to increase translational efficiency in the presence of p180 and SF3b4. These data demonstrate that a unique system comprising a p180-SF3b4-mRNA complex facilitates the selective assembly of polyribosomes on the ER.

Shunji Hattori

Nippi Research Institute of Biomatrix

Evaluation of Keratinocyte Proliferation on Two- and Three-dimensional Type I Collagen Substrates