Cartilage Acidic Protein 2 a hyperthermostable, high affinity calcium-binding protein

Cartilage Acidic Protein a Novel Therapeutic Factor to Improve Skin Damage Repair?

Fish skin has been gaining attention due to its efficacy as a human-wound-treatment product and to identify factors promoting its enhanced action. Skin fibroblasts have a central role in maintaining skin integrity and secrete extra cellular matrix (ECM) proteins, growth factors and cytokines to rapidly repair lesions and prevent further damage or infection. The effects on scratch repair of the ubiquitous but poorly characterized ECM protein, cartilage acidic protein 1 (CRTAC1), from piscine and human sources were compared using a zebrafish SJD.1 primary fibroblast cell line. A classic in vitro cell scratch assay, immunofluorescence, biosensor and gene expression analysis were used. Our results demonstrated that the duplicate sea bass Crtac1a and Crtac1b proteins and human CRTAC-1A all promoted SJD.1 primary fibroblast migration in a classic scratch assay and in an electric cell impedance sensing assay. The immunofluorescence analysis revealed that CRTAC1 enhanced cell migration was most likely caused by actin-driven cytoskeletal changes and the cellular transcriptional response was most affected in the early stage (6 h) of scratch repair. In summary, our results suggest that CRTAC1 may be an important factor in fish skin promoting damage repair.

Deciphering the role of cartilage protein 1 in human dermal fibroblasts: a transcriptomic approach

Cartilage acidic protein 1A (hCRTAC1-A) is an extracellular matrix protein (ECM) of human hard and soft tissue that is associated with matrix disorders. The central role of fibroblasts in tissue integrity and ECM health made primary human dermal fibroblasts (NHDF) the model for the present study, which aimed to provide new insight into the molecular function of hCRTAC1-A. Specifically, we explored the differential expression patterns of specific genes associated with the presence of hCRTAC1-A by RNA-seq and RT-qPCR analysis. Functional enrichment analysis demonstrated, for the very first time, that hCRTAC1-A is involved in extracellular matrix organization and development, through its regulatory effect on asporin, decorin, and complement activity, in cell proliferation, regeneration, wound healing, and collagen degradation. This work provides a better understanding of putative hCRTAC1-A actions in human fibroblasts and a fundamental insight into its function in tissue biology.

Exosomes from adipose-derived stem cells attenuate UVB-induced apoptosis, ROS, and the Ca2+ level in HLEC cells

Cartilage acid protein 1 (CRTAC1) encodes a protein containing the Ca²⁺binding domain, which can promote apoptosis of human lens epithelial cells (HLECs) induced by ultraviolet B radiation. Exosomes secreted from adipose-derived stem cells (ASC-exo) have been used to treat many diseases, but the effect of ASC-exo on cataracts has not been established. We hypothesized that ASC-exo has a therapeutic effect on cataracts by regulating CRTAC1. We established the UVB-induced injured HLECs model to test the interactions between CRTAC1 and miR-10a-5p, and the effect on the Ca²⁺ level and reactive oxygen species (ROS) generation in apoptotic HLECs. We found that UVB significantly increased the level of CRTAC1 expression and induced HLEC apoptosis, while ASC-exo inhibited the induction of UVB and exosome inhibitor reduced the inhibition of ASC-exo. The qRT-PCR results showed that miR-10a-5p had a low level of expression in cataract lesions, whereas CRTAC1 was highly expressed. There was a negative correlation between the expression of CRTAC1 and miR-10a-5p. ASC-exo reversed UVB-inhibited miR-10a-5p expression and miR-10a-5p negatively regulated CRTAC1. In vitro data showed that miR-10a-5p reversed UVB-induced ROS, apoptosis, and the Ca²⁺ level in HLECs. Overexpression of CRTAC1 reversed the induction of ASC-exo in UVB-injured HLECs, and low expression of CRTAC1 reversed the induction of miR-10a-5p inhibitor. By upregulating the level of miR-10a-5p expression and downregulating the level of CRTAC1 expression, exosomes from ASCs attenuated UVB-induced apoptosis, ROS generation, and the Ca²⁺ level in HLECs. Our research provides novel insight into the treatment methods and associated mechanisms underlying cataracts.

Cartilage acidic protein 1 promotes increased cell viability, cell proliferation and energy metabolism in primary human dermal fibroblasts

Cartilage acidic protein 1 (CRTAC1) is an extracellular matrix protein of human chondrogenic tissue that is also present in other vertebrates, non-vertebrate eukaryotes and in some prokaryotes. The function of CRTAC1 remains unknown but the protein's structure indicates a role in cell-cell or cell-matrix interactions and calcium-binding. The aim of the present study was to evaluate the in vitro effects of hCRTAC1-A on normal human dermal fibroblasts (NHDF). A battery of in vitro assays (biochemical and PCR), immunofluorescence and a biosensor approach were used to characterize the protein's biological activities on NHDF cells in a scratch assay. Gene expression analysis revealed that hCRTAC1-A protein is associated with altered levels of expression for genes involved in the processes of cell proliferation (CXCL12 and NOS2), cell migration (AQP3 and TNC), and extracellular matrix-ECM regeneration and remodeling (FMOD, TIMP1, FN1) indicating a role for hCRTAC1-A in promoting these activities in a scratch assay. In parallel, the candidate processes identified by differential gene transcription were substantiated and extended using Electric cell-substrate impedance sensing (ECIS) technology, immunofluorescence and cell viability assays. Our findings indicate that hCRTAC1-A stimulated cell proliferation, migration and ECM production in primary human fibroblasts in vitro.

A thyroid hormone regulated asymmetric responsive centre is correlated with eye migration during flatfish metamorphosis

Flatfish metamorphosis is a unique post-embryonic developmental event in which thyroid hormones (THs) drive the development of symmetric pelagic larva into asymmetric benthic juveniles. One of the eyes migrates to join the other eye on the opposite side of the head. Developmental mechanisms at the basis of the acquisition of flatfish anatomical asymmetry remain an open question. Here we demonstrate that an TH responsive asymmetric centre, determined by deiodinase 2 expression, ventrally juxtaposed to the migrating eye in sole (Solea senegalensis) correlates with asymmetric cranial ossification that in turn drives eye migration. Besides skin pigmentation that is asymmetric between dorsal and ventral sides, only the most anterior head region delimited by the eyes becomes asymmetric whereas the remainder of the head and organs therein stay symmetric. Sub-ocular ossification is common to all flatfish analysed to date, so we propose that this newly discovered mechanism is universal and is associated with eye migration in all flatfish.

Structural and functional maturation of skin during metamorphosis in the Atlantic halibut (Hippoglossus hippoglossus)

To establish if the developmental changes in the primary barrier and osmoregulatory capacity of Atlantic halibut skin are modified during metamorphosis, histological, histochemical, gene expression and electrophysiological measurements were made. The morphology of the ocular and abocular skin started to diverge during the metamorphic climax and ocular skin appeared thicker and more stratified. Neutral mucins were the main glycoproteins produced by the goblet cells in skin during metamorphosis. Moreover, the number of goblet cells producing neutral mucins increased during metamorphosis and asymmetry in their abundance was observed between ocular and abocular skin. The increase in goblet cell number and their asymmetric abundance in skin was concomitant with the period that thyroid hormones (THs) increase and suggests that they may be under the control of these hormones. Several mucin transcripts were identified in metamorphosing halibut transcriptomes and Muc18 and Muc5AC were characteristic of the body skin. Na⁺, K⁺-ATPase positive (NKA) cells were observed in skin of all metamorphic stages but their number significantly decreased with the onset of metamorphosis. No asymmetry was observed between ocular and abocular skin in NKA cells. The morphological changes observed were linked to modified skin barrier function as revealed by modifications in its electrophysiological properties. However, the maturation of the skin functional characteristics preceded structural maturation and occurred at stage 8 prior to the metamorphic climax. Treatment of Atlantic halibut with the THs disrupter methimazole (MMI) affected the number of goblet cells producing neutral mucins and the NKA cells. The present study reveals that the asymmetric development of the skin in Atlantic halibut is TH sensitive and is associated with metamorphosis and that this barrier's functional properties mature earlier and are independent of metamorphosis.

Molecular cloning and functional characterization of a monoterpene synthase isolated from the aromatic wild shrub Thymus albicans

The essential oil of Thymus albicans Hoffmanns. & Link, a native shrub from the Iberian Peninsula, is mainly composed of monoterpenes. In this study, a 1,8-cineole synthase was isolated from the 1,8-cineole chemotype. A partial sequence that lacked the complete plastid transit peptide but contained an extended C-terminal when compared to other related terpene synthases was generated by PCR and Rapid Amplification of cDNA Ends (RACE). The predicted mature polypeptide was 593 amino acids in length and shared 78% and 77% sequence similarity with the homologue 1,8-cineole synthase from Rosmarinus officinalis and Salvia officinalis, respectively. The putative protein possessed the characteristic conserved motifs of plant monoterpene synthases including the RRx₈W and DDxxD motifs and phylogenetic analysis indicated that the amplified 1,8-cineole synthase bears greater sequence similarity with other 1,8-cineole synthases from Lamiaceae family relative to the terpene synthases from the genus Thymus. Functional expression of the recombinant protein in Escherichia coli revealed that in the presence of geranyl diphosphate (GPP) 1,8-cineole was the major product but that its production was too low for robust quantification. Other minor conversion products included α-pinene, β-pinene, sabinene and β-myrcene suggesting the isolated 1,8-cineole synthase may be a multi-product enzyme. To our knowledge, this is the first report of a functionally characterized monoterpene synthase from Thymus albicans.

Chronic stress impairs the local immune response during cutaneous repair in gilthead sea bream (Sparus aurata, L.)

Scale removal in fish triggers a damage-repair program to re-establish the lost epidermis and scale and an associated local immune response. In mammals, chronic stress is known to delay wound healing and to modulate the cutaneous stress axis, but this is unstudied in teleost fish the most successful extant vertebrates. The present study was designed to test the hypothesis that chronic stress impairs cutaneous repair in teleost fish as a consequence of suppression of the immune response. The hypothesis was tested by removing the scales and damaging the skin on one side of the body of fish previously exposed for 4 weeks to a chronic crowding stress and then evaluating cutaneous repair for 1 week. Scale removal caused the loss of the epidermis although at 3days it was re-established. At this stage the basement membrane was significantly thicker (p=0.038) and the hypodermis was significantly thinner (p=0.016) in the regenerating skin of stressed fish relative to the control fish. At 3days, stressed fish also had a significantly lower plasma osmolality (p=0.015) than control fish indicative of reduced barrier function. Chronic stress caused a significant down-regulation of the glucocorticoid receptor (gr) in skin before damage (time 0, p=0.005) and of star at 3 and 7days (p<0.05) after regeneration relative to control fish. In regenerating skin key transcripts of cutaneous repair, pcna, colivα1 and mmp9, and the inflammatory response, tgfβ1, csf-1r, mpo and crtac2, were down-regulated (p<0.05) by chronic stress. Irrespective of chronic stress and in contrast to intact skin many hyper pigmented masses, putative melanomacrophages, infiltrated the epidermis of regenerating skin. This study reveals that chronic stress suppresses the local immune response to scale removal and impairs the expression of key transcripts of wound healing. Elements of the stress axis were identified and modulated by chronic stress during cutaneous repair in gilthead seabream skin.