Glandular matrices and secretions: Blood-feeding arthropods

Abstract

Blood-feeding evolved independently in various arthropod lineages and this is evident in the compositions of the secretory component of their salivary gland transcriptomes (sialomes). Salivary gland-derived secretory proteins modulate the vertebrate host's defenses (hemostatic and immune responses) and assist the hematophagous arthropod to successfully obtain a blood meal. Salivary proteins not only modulate host defenses, but also assist in the creation of a feeding site, or hematoma, by secretion of enzymes that can remodel the host's dermis extracellular matrix. The host's extracellular matrix also plays an important role in the initiation of hemostatic and inflammatory responses and blood-feeding arthropods have evolved molecules that specifically interfere with these responses. As such, vector-host interaction may be seen as interplay between the vertebrate host's extracellular matrix and the salivary-derived "extra-cellular matrix" of the arthropod. Our understanding of this interplay is still rudimentary given the fact that we do not know the functions of the majority of secretory proteins in all sialomes. The rapid expansion of sialome diversity as discovered with next-generation technologies contributes towards this, but also holds the promise that we will be able to grasp the structure of the sialoverse in the future.