Abstract
Phospholipase A2 enzymes are key inflammatory mediators that
are present in many venoms, particularly those of hymenoptera (Bees, Wasps and Ants). In order to discover new inhibitors we embarked on a hit finding
strategy using the Targeted-Venom Discovery Array™ hit finding strategy. Venom
libraries contain a diversity of pharmacological actives, including
microproteins and peptides, which deliver hits on nearly all targets,
especially those difficult to hit with small molecule libraries.
The spider
venoms were selected based on internal data as there are no described bee venom
PLA2 inhibitors known from spiders, although they are well described from snake
venoms. It is thought that the snake venom PLA2 inhibitors have co evolved with
the venom PLA2 enzymes thus protecting the snake’s venom glands from the
actions of its own venom.
Venom from the giant white knee spider (Acanthoscurria
geniculate) was identified in hit finding and confirmed by dose response to
inhibit bee venom PLA2 using the EnzCheck® Phospholipase A2 assay kit (Molecular
Probes®) in 384 mode. Modifications to the assay protocol such as a reduction
in the substrate concentration allowed for greater sensitivity and twice as
many data points from each assay kit. In conclusion the Targeted- Venom
Discovery Array™ worked successfully as a hit finding strategy for novel PLA2
inhibitors.
