Inhalable dry powder formulations of siRNA and pH-responsive peptides with antiviral activity against H1N1 influenza virus.

Pulmonary delivery of siRNA has considerable therapeutic potential for treating viral respiratory infectious diseases including influenza. By introducing siRNA that targets the conserved region of viral genes encoding nucleocapsid protein (NP), viral mRNAs can be degraded and viral replication can be inhibited in mammalian cells. To enable siRNA to be used as an antiviral agent, the nucleic acid delivery barrier must be overcome.

Dynamic localisation of mature microRNAs in Human nucleoli is influenced by exogenous genetic materials.

Although microRNAs are commonly known to function as a component of RNA-induced silencing complexes in the cytoplasm, they have been detected in other organelles, notably the nucleus and the nucleolus, of mammalian cells. We have conducted a systematic search for miRNAs in HeLa cell nucleoli, and identified 11 abundant miRNAs with a high level of nucleolar accumulation. Through in situ hybridisation, we have localised these miRNAs, including miR-191 and miR-484, in the nucleolus of a diversity of human and rodent cell lines.

Genogroup I and II picobirnaviruses in respiratory tracts of pigs.

Sequence-independent amplification and specific reverse transcription PCRs identified genogroup I and II picobirnaviruses in respiratory tracts of pigs. These data expand knowledge of picobirnavirus diversity and tropism. Genetic relationships between porcine respiratory and human enteric picobirnaviruses suggest cross-species transmission of picobirnaviruses between pigs and humans.

The constitutive activity of the ghrelin receptor attenuates apoptosis via a protein kinase C-dependent pathway.

The ghrelin receptor (GHS-R1a) displays a high level of constitutive signaling through a phospholipase C/protein kinase C-dependent pathway. Therefore, we have investigated the role of agonist-dependent and agonist-independent signaling of GHS-R1a in apoptosis using the seabream GHS-R1a stably expressed in human embryonic kidney 293 cells (HEK-sbGHS-R1a cells). Cadmium-induced activation of caspase-3 was significantly attenuated in HEK-sbGHS-R1a cells compared to wild-type HEK293 cells, while the apoptotic responses to the protein kinase C inhibitor staurosporine were similar.

The truncated ghrelin receptor polypeptide (GHS-R1b) acts as a dominant-negative mutant of the ghrelin receptor.

The dimerization properties of the ghrelin receptor (GRLN-R) and its non-signalling, naturally occurring, truncated splice variant (GHS-R1b) have been investigated in human embryonic kidney 293 cells heterologously expressing these proteins. Using the techniques of bioluminescence resonance energy transfer and co-immunoprecipitation, we detected the formation of GRLN-R homodimers and GRLN-R/GHS-R1b heterodimers, but ghrelin-induced conformational changes were only detected in the GRLN-R homodimers. When the expression of GHS-R1b exceeded that of GRLN-R, there was a decrease in the cell surface expression of GRLN-R with a consequent decrease in constitutive activation of phosphatidylinositol-specific phospholipase C (PI-PLC).

Over-expression of the truncated ghrelin receptor polypeptide attenuates the constitutive activation of phosphatidylinositol-specific phospholipase C by ghrelin receptors but has no effect on ghrelin-stimulated extracellular signal-regulated kinase 1/2 activity.

In addition to regulating growth hormone release from the pituitary, ghrelin receptors also influence cell proliferation and apoptosis. By studying mitogen-activated protein kinase activity in human embryonic kidney 293 cells over-expressing ghrelin receptors, we aimed to identify the specific cell signalling pathways used by ghrelin receptors, and to determine if the truncated ghrelin receptor polypeptide had any influence on the functional activity of ghrelin receptors. We found that ghrelin activated extracellular signal-regulated kinases 1/2 with an EC50 value of 10 nM, and that this response was inhibited by the ghrelin receptor antagonists D-Lys3-GHRP-6 and [D-Arg1,D-Phe5,D-Trp(7,9),Leu11]-substance P.