Abstract 15916: Role of Small-cajal Body Associated RNAs (scaRNAs) in Regulation of Cardiomyogenesis

Introduction: The requirement of non-coding RNAs particularly scaRNAs are playing a critical role in alternative splicing and maturation of mRNAs. Dysregulated splicing of mRNAs has been shown to cause heart defects. In this study, we are comparing the role of scaRNAs during differentiation of induced pluripotent stem cells (iPSCs) into cardiomyocytes (iCMCs) from normal individual and Noonan syndrome (NS) patient. We have selected NS patient cells because it is an autosomal dominant genetic disorder which leads to cardiomyopathy and congenital heart defects in humans. Hypothesis: We hypothesize that scaRNA1 and scaRNA20 have a significant role in the development of cardiomyocytes, and these scaRNAs are dysfunctional in iCMCs derived from NS. Methods and Results: We have compared the normal skin fibroblast-derived iPSCs (N-iPSCs) and N-iCMCs with NS patient-derived NS-iPSCs and NS-iCMCs using quantitative RT-PCR, Western blot and immunofluorescence analyses. We also used the knockdown and overexpression of scaRNA1 and scaRNA20 approaches to delineate the importance of these scaRNAs during cardiomyogenesis. Our qRT-PCR data showed a significantly lower expression of scaRNA1 and scaRNA20 (Fig. A) as well as the cardiac-specific genes CTT and GATA4 (Fig. B) in NS-iCMCs when compared to the normal iCMCs. Furthermore, the qRT-PCR data from the scaRNA20 overexpressed N-iCMC showed an increased expression of cardiac-specific genes (Fig. C) when compared to the N-iCMCs. These studies clearly indicate that scaRNA1 and scaRNA20 plays an important role in cardiomyogenesis. Further studies are underway to explore the mechanisms of these scaRNAs in regulation of cardiac genes. Conclusions: Our findings indicate that scaRNA1 and scaRNA20 are involved in mRNA splicing and maturation of cardiac genes. Moreover, these scaRNAs are dysfunctional in NS patient’s iCMCs and targeting these molecules will have a therapeutic potential for a patient with NS.

Overexpression of miR-340-5p Inhibits Skin Fibroblast Proliferation by Targeting Kruppel-like Factor 2

<P>Objective: MicroRNA (miR)-340-5p has been identified to play a key role in several cancers. However, the function of miR-340-5p in skin fibroblasts remains largely unknown. </P><P> Methods: Gain of function experiments were performed by infecting normal skin fibroblast cells with a lentivirus carrying 22-bp miR-340-5p. Cell proliferation was detected by Cell Counting Kit-8 (CCK-8) assay. To uncover the mechanisms, mRNA-seq was used. Differentially expressed mRNAs were further determined by Gene Ontology and KEGG pathway analyses. The protein levels were analysed by Western blotting. A dual-luciferase reporter assay was used to detect the direct binding of miR-340-5p with the 3&#039;UTR of Kruppel-like factor 2 (KLF2). </P><P> Results: MiR-340-5p lentivirus infection suppressed normal skin fibroblast proliferation. The mRNAseq data revealed that 41 mRNAs were differentially expressed, including 22 upregulated and 19 downregulated transcripts in the miR-340-5p overexpression group compared with those in the control group. Gene Ontology and KEGG pathway analyses revealed that miR-340-5p overexpression correlated with the macromolecule biosynthetic process, cellular macromolecule biosynthetic process, membrane, and MAPK signalling pathway. Bioinformatics analysis and luciferase reporter assays showed that miR-340-5p binds to the 3&#039;UTR of KLF2. Forced expression of miR-340-5p decreased the expression of KLF2 in normal skin fibroblasts. Overexpression of KLF2 restored skin fibroblast proliferation in the miR-340-5p overexpression group. </P><P> Conclusion: This study demonstrates that miR-340-5p may suppress skin fibroblast proliferation, possibly through targeting KLF2. These findings could help us understand the function of miR-340-5p in skin fibroblasts. miR-340-5p could be a therapeutic target for preventing scarring.</P>

Is leukotriene B4 one of the keloid marker? a fibroblast keloid study

Keloid pathogenesis occurs due to the duration of prolonged inflammatory phase and increased production of various growth factors such as TGF-β1 which may cause increasing fibroblast proliferation and collagen synthesis. Existence of one of the chemical mediators released during inflammation, leukotriene B4 (LTB4), in keloid pathogenesis specifically in the phases of inflammation and proliferation, is still unclear. The purpose of the study is to analyze the levels of LTB4 in keloid. Methods: Fibroblast culture that was done by explanting keloid and normal skin of a keloid patient. Measurement of LTB4 on keloid and normal fibroblast was done by Elisa method. This experiment was run in triplicate. Statistical test was conducted by t test for the unpaired data and Anova test. The experiment was done at cell culture laboratory of Medical Faculty of Padjadjaran University Bandung. Levels of LTB4 in keloid fibroblast was higher than that of normal skin fibroblast (mean 23143.27 vs 18191.85 pg/ml; p<0.05). Conclusion, increased LTB4 levels in keloid fibroblast showed the existence of LTB4 role in the prolonged inflammatory process in keloid pathogenesis.

Synthesis and Antiproliferative Activity of Marine Bromotyrosine Purpurealidin I and Its Derivatives

The first total synthesis of the marine bromotyrosine purpurealidin I (1) using trifluoroacetoxy protection group and its dimethylated analog (29) is reported along with 16 simplified bromotyrosine derivatives lacking the tyramine moiety. Their cytotoxicity was evaluated against the human malignant melanoma cell line (A-375) and normal skin fibroblast cells (Hs27) together with 33 purpurealidin-inspired simplified amides, and the structure–activity relationships were investigated. The synthesized simplified analogs without the tyramine part retained the cytotoxic activity. Purpurealidin I (1) showed no selectivity but its simplified pyridin-2-yl derivative (36) had the best improvement in selectivity (Selectivity index 4.1). This shows that the marine bromotyrosines are promising scaffolds for developing cytotoxic agents and the full understanding of the elements of their SAR and improving the selectivity requires further optimization of simplified bromotyrosine derivatives.

Anti-Trypanosomal Activity of Diarylheptanoids Isolated from the Bark ofAlnus japonica

The crude extract of Alnus japonica bark exhibited a strong effect on the growth of Trypanosoma brucei. Subsequent chromatographic separation resulted in the isolation of two novel diarylheptanoids, known as alnuside C (2) and alnuside D (3), and three known compounds, 1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptan-3(R)-O-β-D-glucopyranoside (1), oregonin (4) and hirsutanone (5). The structures of the isolates were elucidated based on the use of extensive spectroscopic and chemical methods. Among the isolated diarylheptanoids, oregonin (4) (a major component of plant bark) and hirsutanone (5) exhibited potent in vitro inhibitory activity against T. brucei growth in the bloodstream with IC50values of 1.14 and 1.78 μM, respectively. We confirmed that oregonin (4) and hirsutanone (5) were not toxic to human normal skin fibroblast cells (NB1RGB) and colon cancer cells (HCT-15) at a concentration of 50 μM; however, lower levels of toxicity were observed for leukemia cells. To determine the structure activity relationships of the isolated components, we performed Conformation Search and found that the 3-oxo function of the heptane chain in the diarylheptanoid molecule is required for their trypanocidal activity.