RNA delivery by extracellular vesicles in mammalian cells and its applications.

The term 'extracellular vesicles' refers to a heterogeneous population of vesicular bodies of cellular origin that derive either from the endosomal compartment (exosomes) or as a result of shedding from the plasma membrane (microvesicles, oncosomes and apoptotic bodies). Extracellular vesicles carry a variety of cargo, including RNAs, proteins, lipids and DNA, which can be taken up by other cells, both in the direct vicinity of the source cell and at distant sites in the body via biofluids, and elicit a variety of phenotypic responses. Owing to their unique biology and roles in cell-cell communication, extracellular vesicles have attracted strong interest, which is further enhanced by their potential clinical utility. Because extracellular vesicles derive their cargo from the contents of the cells that produce them, they are attractive sources of biomarkers for a variety of diseases. Furthermore, studies demonstrating phenotypic effects of specific extracellular vesicle-associated cargo on target cells have stoked interest in extracellular vesicles as therapeutic vehicles. There is particularly strong evidence that the RNA cargo of extracellular vesicles can alter recipient cell gene expression and function. During the past decade, extracellular vesicles and their RNA cargo have become better defined, but many aspects of extracellular vesicle biology remain to be elucidated. These include selective cargo loading resulting in substantial differences between the composition of extracellular vesicles and source cells; heterogeneity in extracellular vesicle size and composition; and undefined mechanisms for the uptake of extracellular vesicles into recipient cells and the fates of their cargo. Further progress in unravelling the basic mechanisms of extracellular vesicle biogenesis, transport, and cargo delivery and function is needed for successful clinical implementation. This Review focuses on the current state of knowledge pertaining to packaging, transport and function of RNAs in extracellular vesicles and outlines the progress made thus far towards their clinical applications

Comparison of two shrub rose genotypes using architectural analysis

 The aesthetic value of an ornamental plant is highly dependant on its shape. This is primarily determined by the characteristics of its axes at the following levels: (1) morphological (size of the different constituent elements) (2) topological (branching relationships) and (3) spatial (position of the axes in space). Architectural analysis therefore appears to be an interesting method for characterising plant shape and for assessing its aesthetic value. This method seems to be particularly well adapted to an ornamental shrub such as the rose bush that has a visibly complex architecture. The analysis took place on two cultivars of the shrub rose Rosa hybrida, Knock Out® cv Radrazz and Lovely Meilland® cv Meiratcan. Quantitative experimental data (morphological and topological) were obtained on plants grown from metamers cuttings in a greenhouse for five months. Fifteen plants per cultivar were fully described. Data was analysed using the Multi Tree Scale method (MTG) (Godin C. and Caraglio Y. 1998). This method made it possible to obtain a database for each cultivar that included the different related architectural scale levels, morphological entities and variables (attributes). By analysing this database, we were able to clearly identify the dominant architectural elements common to the two cultivars, such as the existence of two types of axes (long and short) and the position of these axes according to branching order. Moreover, it also allowed us to identify the architectural characteristics that differentiate the two genotypes, such as the number of branching orders, the number of flower-bearing branches and their length. This precise and quantitative analysis of shrub architecture is a powerful method for describing shrub shape. It may therefore be an invaluable tool for breeders, for example, who want to accurately characterise the architecture of different genotypes in order to impose selection pressure on objective criteria. The same is true for the researcher who would like to assess the effect of various treatments on plant shape, such as in the case of pruning or the application of a growth regulator