Endogenous polymer

Burlde A (2005) Poly(ADP-ribose). The most elaborate metabolite of NAD. Febs J 272 4576-4589 Burlde A, Brabeck C, Diefenbach J, Beneke S (2005) The emerging role of poly(ADP-ribose) polymerase-1 in longevity. Int J Biochem Cell Biol 37 1043—1053 Cardenas-Corona M, Jacobson E, Jacobson M (1987) Endogenous polymers of ADP-ribose are associated with the nuclear matrix. J Biol Chem 262 14863—14866 Chang P, Jacobson MK, Mitchison TJ (2004) Poly(ADP-ribose) is required for spindle assembly and structure. Nature 432 645-649... 

Cardenas-CoTona, M. E., jacobson, E. L., and Jacobson, M. K. (1987). Endogenous polymers of ADP-ribose ate associated vcith tlie nuclear matrix. /. Biol. Cbem. 262, 14865-14866. 

These results suggest caution in attributing the effects of benzamides to the inhibition of nuclear ADP-ribosyl transferase unless that inhibition can be demonstrated by a decrease in the level of endogenous polymer synthesis. Intracellular concentrations of nuclear ADP-ribosyl transferase inhibitors have seldom been measured. In one case an extracellular benzamide concentration of 1 mM gave an intranuclear concentration of 4-8 pM (5). Nanomolar concentrations may well be achieved under other experimental conditions. The conflicting reports of the effects on whole cells with benzamides may be due to activation and inhibition of nuclear ADP-ribosyl transferase taking place under different experimental conditions. 

Endogenous Polymers as Biomaterials for Nanoparticulate Gene Therapy... 

Keywords Gene therapy, non-viral vectors, drug delivery, nanoparticles, endogenous polymers, proteins, carbohydrates... 

Characteristics of Currently Proposed Nanosystems Based on Endogenous Polymers... 

An additional key aspect is to determine if we can use a selected endogenous polymer in its natural state or if we need to modify it in order to improve its characteristics. 

Figure 8.1 Use of endogenous polymers in nanoparticle formation as endogenous polymers in puris naturabilis, as modified endogenous polymers or using combinations of both as well as with other synthetic/semi-synthetic polymers (hybrid nanoparticles).

Table 8.1 Main endogenous polymers used in the preparation of nanoparticles for gene...

Another important consideration when using endogenous polymers is the source of such polymers. Some of them, such as hyaluronic acid and albumin, can already be foimd as recombinant biotechnology products. However, some other polymers, such... 

Figure 8.2 Examples of ligands used to provide new features to endogenous polymers.

To obtain a benefit from the properties of the aforementioned moieties while preserving the delicate nature and properties of the endogenous polymers, modification reactions should be mild and preferably take place in aqueous environment. Harsh conditions may result in hydrolysis, irreversible lost of endogenous polymer conformation... 

Some other endogenous polymers have not yet consolidated their use as biomaterials for nanoparticulate-based gene delivery, but they offer interesting possibilities that may be exploited in upcoming years. 

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