Molecular-and-ultrastructural-studies-of-a-fibrillar-collagen-from-octocoral-of-Technology-3440-S-t

Dearborn Ave, Chicago, IL 60616, USA.University, Ramat Aviv, Tel Aviv 69978, Israel.Aviv University, Tel Aviv 69978, Israel.We report here the biochemical, molecular and ultrastructural features of a unique organization of fibrillar collagen extracted from the octocoral Sarcophyton ehrenbergi Collagen, the most abundant protein in the animal kingdom, is often defined as a structural component of extracellular matrices in metazoans. In the present study, collagen fibers were extracted from the mesenteries of S. ehrenbergi polyps.

These fibers are organized as filaments and further compacted as coiled fibers. The fibers are uniquely long, reaching an unprecedented length of tens of centimeters. The diameter of these fibers is 9±07 μm. The amino acid content of these fibers was identified using chromatography and revealed close similarity in content to mammalian type I and II collagens. The ultrastructural organization of the fibers was characterized by means of high-resolution microscopy and X-ray diffraction. The fibers are composed of fibrils and fibril bundles in the range of 15 to 35 nm. These data indicate a fibrillar collagen possessing structural aspects of both types I and II collagen, a highly interesting and newly described form of fibrillar collagen Conflict of interest statement: Competing interestsThe authors declare no 10016/j.

bbagen02029629. Epub 2020 Apr 29.Matrix vesicle biomimetics harboring Annexin A5 and alkaline phosphatase bind to the native collagen matrix produced by mineralizing vascular smooth muscle Surgery, Roma, Italy; Sanford Burnham Prebys Medical Discovery Institute, La Sciences, University of Leuven, Leuven, Belgium.BACKGOUND: Vascular smooth muscle cells (VSMCs) transdifferentiated ectopically trigger vascular calcifications, contributing to clinical cardiovascular disease in the aging population. AnxA5 and TNAP play a crucial role in METHODS: We performed affinity studies between DPPC and 9:1 DPPC:DPPS-proteoliposomes carrying AnxA5 and/or TNAP and different types of collagen matrix: type I, II, I + III and native collagenous extracellular matrix (ECM) produced from VSMCs with or without differentiation, to simulate ectopic RESULTS: AnxA5-proteoliposomes had the highest affinity for collagens, specially for type II. collagen benefits -proteoliposomes bound poorly and the simultaneous presence of TNAP in the AnxA5-proteoliposomes disturbed interactions between AnxA5 and collagen. DPPC AnxA5-proteoliposomes affinities for ECM from transdifferentiating cells went up 2-fold compared to that from native VSMCs.

The affinities of DPPC:DPPS-proteoliposomes were high for ECM from VSMCs with or without differentiation, underscoring a synergistic effect between AnxA5 and DPPS. Co-localization studies uncovered binding of proteoliposomes harboring AnxA5 or TNAP+AnxA5 to various regions of the ECM, not limited to type II CONCLUSION: AnxA5-proteoliposomes showed the highest affinities for type II collagen, deposited during chondrocyte mineralization in joint cartilage. TNAP in the lipid/protein microenvironment disturbs interactions between AnxA5 and collagen. These findings support the hypothesis that TNAP is cleaved from the MVs membrane just before ECM binding, such facilitating MV anchoring to ECM via GENERAL SIGNIFICANCE: Proteoliposomes as MV biomimetics are useful in the understanding of mechanisms that regulate the mineralization process and may be essential for the development of novel therapeutic strategies to prevent or Conflict of interest statement: Declaration of Competing Interest All authors Increase in dermal collagen fibril diameter and elastogenesis with UVB exposure: an optical and ultrastructural study in albino Balb/c mice.Cutaneous aging is a complex biological phenomenon, dependent not only on the innate or intrinsic process ("biological clock"), but also on extrinsic elements, primarily chronic sun exposure (photoaging). In order to verify dermal morphological changes in the elastic fiber system and collagen associated with aged skin, we performed a light and electron microscopic study on exposed-shaved albino mice, which were exposed to UVB radiation. The experimental group consisted of 48 exposed animals, randomly distributed in three groups and submitted to different radiation doses (A, 28800 J/m2; B, 57600 J/m2; and C, 86400 J/m2) and studied 0, 30, 60 and 90 days of exposure discontinuation.

Nonexposed-shaved and nonexposed-nonshaved animals were included as controls. From collagen powder of exposure discontinuation and subsequently, the elastic system and collagen network were progressively modified. The increase in collagen fibril diameter was prominent in the 60 and 90 day groups (p<05), as noticed on electron microscopy. Elastic fiber density also increased after irradiation (p<05). On electron microscopy, elastogenesis was seen in the deep dermis. The comparative study among the groups disclosed clear relationship between doses and "elastotic changes". It also showed that chronological aging of mice skin was apparently intensified after UVB exposure.