Biosynthesis of spathulenol and camphor stand as a competitive route to artemisinin production as revealed by a new chemometric convergence approach based on nine locations’ field-grown Artemesia annua L.

Since isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) are the universal precursors of both essential oil components, and the antimalarial agent artemisinin and its derivatives in Artemesia annua L., this paper aims to correlate the spotted differences in their concentrations by screening Artemesia annua L. field-grown in nine locations around the world that may reveal the role of any these compounds as precursors or competitors in the biosynthetic pathway of the sesquiterpene lactone : artemisinin. Principal component analysis (PCA) revealed that artemisinin is positively correlated to β-pinene, 1.8-cineole, sabinene hydrate, borneol and 1-octen-3-ol; but negatively to artemisinic acid and β-caryophyllene oxide. Hierarchical cluster analysis (HCA) classified locations into two distinct groups in which artemisinin concentration stood as the main driving factor to build similarities between the locations. In parallel, an improved convergence approach based on idiosyncratic similarities able to capture heterogeneity across individuals is proposed, which was able to classify compounds into four distinct clusters. Artemisinin appeared to be cross-linked to p-cymene, cis-carvyle acetate, 4-terpinene-1-ol, β-caryophyllene, β-farnesene, β-selinene, α-selinene, β-caryophyllene oxide and α-costol. It is interesting to see how camphor and spathulenol behaved as a distinct cluster group, which suggests that biosynthesis of these two compounds follows a different but a competitive pathway ; thus limiting their production could be a key to control and enhance the production of artemisinin

Novel palladium(II) and platinum(II) complexes with a fluoropiperazinyl based ligand exhibiting high cytotoxicity and anticancer activity in vitro

cis-Dichloro-palladium(II) and cis-dichloro-platinum(II) complexes (2, 4) of the general formula [M(N-N)Cl2] (M=Pd(II) and Pt(II), N-N= 1,2-diamino-4-fluoro-5-(4-methyl-1-piperazinyl) benzene, (DFMPB)) and the dicationic palladium(II) complex [Pd(N-N)(CH3CN)2](BF4)2 (3) have been prepared and characterized by elemental analysis, 1H-NMR-, mass spectroscopy, and IR spectroscopy. The cytotoxic effect of these complexes against MDA-231 and MCF-7 human breast cancer cell lines and K562 human leukemia cell line has been studied. The influence was dose dependent and varies with cell type. The palladium(II) complex (2) showed superior cytotoxic effect compared with the corresponding platinum(II) complex and the standard, cisplatin, when tested against all the above cell lines. 2016 Kayed A. Abu-Safieh et al.Scopu

Stimulatory effects of Lycium shawii on human melanocyte proliferation, migration, and melanogenesis: In vitro and in silico studies

There is no first-line treatment for vitiligo, a skin disease characterized by a lack of melanin produced by the melanocytes, resulting in an urgent demand for new therapeutic drugs capable of stimulating melanocyte functions, including melanogenesis. In this study, traditional medicinal plant extracts were tested for cultured human melanocyte proliferation, migration, and melanogenesis using MTT, scratch wound-healing assays, transmission electron microscopy, immunofluorescence staining, and Western blot technology. Of the methanolic extracts, Lycium shawii L. (L. shawii) extract increased melanocyte proliferation at low concentrations and modulated melanocyte migration. At the lowest tested concentration (i.e., 7.8 μg/mL), the L. shawii methanolic extract promoted melanosome formation, maturation, and enhanced melanin production, which was associated with the upregulation of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein (TRP)-1 and TRP-2 melanogenesis-related proteins, and melanogenesis-related proteins. After the chemical analysis and L. shawii extract-derived metabolite identification, the in silico studies revealed the molecular interactions between Metabolite 5, identified as apigenin (4,5,6-trihydroxyflavone), and the copper active site of tyrosinase, predicting enhanced tyrosinase activity and subsequent melanin formation. In conclusion, L. shawii methanolic extract stimulates melanocyte functions, including melanin production, and its derivative Metabolite 5 enhances tyrosinase activity, suggesting further investigation of the L. shawii extract-derived Metabolite 5 as a potential natural drug for vitiligo treatment

siRNA Silencing of Proteasome Maturation Protein (POMP) Activates the Unfolded Protein Response and Constitutes a Model for KLICK Genodermatosis

Keratosis linearis with ichthyosis congenita and keratoderma (KLICK) is an autosomal recessive skin disorder associated with a single-nucleotide deletion in the 5′untranslated region of the proteasome maturation protein (POMP) gene. The deletion causes a relative switch in transcription start sites for POMP, predicted to decrease levels of POMP protein in terminally differentiated keratinocytes. To investigate the pathophysiology behind KLICK we created an in vitro model of the disease using siRNA silencing of POMP in epidermal air-liquid cultures. Immunohistochemical analysis of the tissue constructs revealed aberrant staining of POMP, proteasome subunits and the skin differentiation marker filaggrin when compared to control tissue constructs. The staining patterns of POMP siRNA tissue constructs showed strong resemblance to those observed in skin biopsies from KLICK patients. Western blot analysis of lysates from the organotypic tissue constructs revealed an aberrant processing of profilaggrin to filaggrin in samples transfected with siRNA against POMP. Knock-down of POMP expression in regular cell cultures resulted in decreased amounts of proteasome subunits. Prolonged silencing of POMP in cultured cells induced C/EBP homologous protein (CHOP) expression consistent with an activation of the unfolded protein response and increased endoplasmic reticulum (ER) stress. The combined results indicate that KLICK is caused by reduced levels of POMP, leading to proteasome insufficiency in differentiating keratinocytes. Proteasome insufficiency disturbs terminal epidermal differentiation, presumably by increased ER stress, and leads to perturbed processing of profilaggrin. Our findings underline a critical role for the proteasome in human epidermal differentiation

The rexinoid, bexarotene, prevents the development of premalignant lesions in MMTV-erbB2 mice

Retinoids, vitamin A analogues that bind to retinoic acid receptor (RAR) or retinoid X receptor (RXR), play important roles in regulating cell proliferation, apoptosis, and differentiation. Recently, RXR-selective ligands, also referred to as rexinoids, have been investigated as potential chemopreventive agents for breast cancer. Our previous studies demonstrated that the rexinoid bexarotene significantly prevented ER-negative mammary tumourigenesis with less toxicity than naturally occurring retinoids in animal models. To determine whether bexarotene prevents cancer at the early stages during the multistage process of mammary carcinogenesis, we treated MMTV-erbB2 mice with bexarotene for 2 or 4 months. The development of preinvasive mammary lesions such as hyperplasias and carcinoma-in-situ was significantly inhibited. This inhibition was associated with reduced proliferation, but no induction of apoptosis. We also examined the regulation of a number of rexinoid-modulated genes including critical growth and cell cycle regulating genes using breast cell lines and mammary gland samples from mice treated with rexinoids. We showed that two of these genes (DHRS3 and DEC2) were modulated by bexarotene both in vitro and in vivo. Identification of these rexinoid-modulated genes will help us understand the mechanism by which rexinoid prevents cancer. Such rexinoid-regulated genes also represent potential biomarkers to assess the response of rexinoid treatment in clinical trials

SUMOylation of DEC1 Protein Regulates Its Transcriptional Activity and Enhances Its Stability

Differentiated embryo-chondrocyte expressed gene 1 (DEC1, also known as sharp2, stra13, or BHLHB2) is a mammalian basic helix-loop-helix protein that is involved in many aspects of gene regulation through acting as a transcription factor. Changes in DEC1 expression levels have been implicated in the development of cancers. Using COS-7 cell, we showed that DEC1 can be modified by the small ubiquitin-like modifiers, SUMO1, 2 and 3. Two major SUMOylation sites (K159 and K279) were identified in the C-terminal domain of DEC1. Substitution of either K159 or K279 with arginine reduced DEC1 SUMOylation, but substitution of both K159 and K279 abolished SUMOylation, and more protein appeared to be retained in the cytoplasm compared to wild-type DEC1. The expression of DEC1 was up-regulated after serum starvation as previously reported, but at the same time, serum starvation also led to more SUMOylation of DEC1. In MCF-7 cells SUMOylation also stabilized DEC1 through inhibiting its ubiquitination. Moreover, SUMOylation of DEC1 promoted its repression of CLOCK/BMAL1-mediated transcriptional activity through recruitment of histone deacetylase1. These findings suggested that posttranslational modification of DEC1 in the form of SUMOylation may serve as a key factor that regulates the function of DEC1 in vivo

Accelerating functional gene discovery in osteoarthritis

Osteoarthritis causes debilitating pain and disability, resulting in a considerable socioeconomic burden, yet no drugs are available that prevent disease onset or progression. Here, we develop, validate and use rapid-throughput imaging techniques to identify abnormal joint phenotypes in randomly selected mutant mice generated by the International Knockout Mouse Consortium. We identify 14 genes with functional involvement in osteoarthritis pathogenesis, including the homeobox gene Pitx1, and functionally characterize 6 candidate human osteoarthritis genes in mouse models. We demonstrate sensitivity of the methods by identifying age-related degenerative joint damage in wild-type mice. Finally, we phenotype previously generated mutant mice with an osteoarthritis-associated polymorphism in the Dio2 gene by CRISPR/Cas9 genome editing and demonstrate a protective role in disease onset with public health implications. We hope this expanding resource of mutant mice will accelerate functional gene discovery in osteoarthritis and offer drug discovery opportunities for this common, incapacitating chronic disease