Bio-Synthesis Newsletter - May 2017

LncRNA, broccoli, sulforaphane, and cancer!

Recently researchers have shown that sulforaphane, a dietary molecule present in broccoli, helps to prevent prostate cancer. These findings suggest that sulforaphane may work through its influence on long non-coding RNAs (lncRNAs). The results were published in the Journal of Nutritional Biochemistry. Sulforaphane is also known to inhibit breast cancer stem cells. It does this by down-regulating the Wnt/β-catenin self-renewal pathway in the cells. Therefore sulforaphane is now considered as a chemopreventive phytochemical for breast cancer. The phytochemical sulforaphane is a biologically active chemical present in many plants including broccoli, kale, Brussels sprouts, cabbage, and other green eatable plants. Synthetic lncRNAs are useful tools for the study of their function in mammalian metabolism.

What is PIF?

PreImplantation Factor (PIF) is a 15-amino acid peptide secreted in embryonic tissue cells of embryos that are capable of living. PIF is a very early marker of fertilization and embryo viability. PIF regulates and enables maternal (host) acceptance and tolerance to the "invading" embryo (allograft) while preserving maternal immunity to fight infections. These attributes are also thought to make PIF a potential therapeutic agent for chronic inflammatory diseases including atherosclerosis. Timely and efficient regulation of blastocyst implantation and fetal growth are essential for the successful reproduction of mammals that give birth to living offsprings. Disruptions in this regulation can result in a wide variety of complications in females that carry embryos in their womb, including infertility, spontaneous abortion, fetal growth restriction, and premature delivery. Synthetic PIF can be used to study its effect in vitro and in vivo such as by investigating its effect in tissue-specific cell cultures.

Scuralose suppresses food intake

Recently researchers from California and Florida have discovered that sucralose, the artificial non-nutritive sweetener used in Splenda, suppresses food intake in flies. The authors reported that animals exposed to sucralose start overeating after exposed to a sucralose-free diet. The researchers reasoned that sucralose ingestion triggers a neuronal response stimulating a fasting state. Since artificial non-nutritive sweetener are widely used the authors suggest that the genetic and neuronal mechanisms influenced by the intake of sucralose will need to be more carefully studied. Sucralose is quite stable and has been detected in waste and surface water. However, it appears that it is not toxic to animals. In 2000 the metabolic and pharmacokinetic profile of sucralose was studied in humans. Radiolabeled sucralose essentially passed unchanged through the human body. Metabolites that appear to be glucuronide conjugates of sucralose were also detected. An allosteric transcription factor (aTF) has been engineered to respond to new ligands including sucralose. The creation of designer aTFs is thought to enable new applications in the control of cell metabolism, cell biology and synthetic gene circuits. In addition, similar constructs could be used for the design of diagnostic tools useful for the detection of small molecules such as artificial sweeteners. 

Dendrimers and Dextramers are useful Research Tools.

Dendrimers are highly branched monodispersed polymers. A functional central core and branching units define their unique characteristics. The interior cavities together with multiple peripheral functional groups facilitate several different applications in biomedicine and bio-organic chemistry. Poly(amidoamine) (PAMAM) based dendrimers using ammonium or ethylenediamine as the core are now the most important type of dendrimers. These can interact and compact DNA plasmids or large DNA molecules via electrostatic interactions to form nanocomposites useful for cell uptake. DNA delivered this way is released via a “sponge effect” favored by buffering effects of tertiary amino groups in the branching units. In 2013 Wu et al. reported the use of dendrimers as carriers for siRNA delivery and gene silencing.     

Dextramers are a form of major histocompatibility complex (MHC) multimers that contain fluorophores, such as fluorescein or others, and MHC molecules or peptides attached to a dextran backbone. These types of dextramers can be used as tools for the detection of antigen-specific T-cells in fluids and tissue samples, for example, using flow cytometry. In general, the detection sensitivity of MHC class II dextramers is higher than that of tetramers. Dextramers can be prepared using three approaches: (1) Derivatization of peptide-tethered soluble MHC molecules; (2) Derivatization of soluble, empty MHC molecules; Or, (3), Derivatization of soluble MHC molecules containing class II-associated chain peptide (CLIP). To avoid separation of the α and β chains, a leucine-zipper dimerization motif from the transcription factors Fos and Jun are usually inserted to the two chains. MHC monomers are biotinylated using biotin ligase while peptide-tethered biotinylated proteins are directly multimerized using streptavidin conjugated fluorophores, such as phycoerythrin or allophycocyanin. However, other approaches are also possible.