The clotting system in decapod crustaceans: History, current knowledge and what we need to know beyond the models

Abstract

Hemolymph coagulation is among the major arms of the humoral immune response in crustaceans. According to the current model, hemolymph clotting in decapod crustacean relies mostly on the polymerization of the plasmatic clotting protein (CP) which is directly promoted by calcium-depended transglutaminase (TGase) released from hemocytes upon microbial stimulus or injury. However, the type of hemocytes containing TGase, and hence how the TGase is released, might vary among species. Thus, we discourse here about possible mechanisms for clotting initiation. On the other hand, the initiation of coagulation reaction in the absence of microbial elicitors is poorly understood and seems to involve hemocytes lability, yet the mechanism remains unknown. A cellular clottable protein called coagulogen, different to the plasma CP, occurs in several species and could be related with the immune response, but the biological relevance of this protein is unknown. It is also demonstrated that the clotting response is actively involved in defense against pathogens. In addition, both TGase and the CP show pleiotropic functions, and although both proteins are relatively conserved, some of their physic-chemical properties vary significantly. The occurrence of differences in the clotting system in crustaceans is conceivable given the high number of species and their diverse ecology. Results from still non-studied decapods may provide explanation for some of the issues presented here from an evolutionary perspective.

Drosophila melanogaster Responses against Entomopathogenic Nematodes: Focus on Hemolymph Clots

“…All clot components in horseshoe crabs, including TG, are present in their hemocytes and are released upon stimulation by LPS [24,27]. This is in contrast to crustaceans, such as crayfish and lobster, in which TG that is derived from hemocytes or other tissues directly polymerizes plasma clottable proteins into clot fibers without the need for a proteolytic cascade [28,29]. Crayfish clottable protein shows no similarity to horseshoe crab coagulogen or mammalian fibrinogen but is instead related at the sequence level to insect vitellogenin with which it shares the presence of a von Willebrand factor D domain (vWF), which is common in mammalian coagulation factors [29,30].…”

Evolution of immune defence responses as incremental layers among Metazoa

“…Hemolymph clotting by protease cascades is also present in crustaceans and insects. In most of the crustacean species, hemolymph coagulation is mediated by the phenoloxidase (PO) cascade and transglutaminase released from hemocytes and catalyzes the polymerization of a clotting protein (Perdomo-Morales et al 2019). In insects, serine proteases containing the arthropod exclusive Clip domain promote pathogen-induced hemolymph clotting.…”

“…bacteria, bacterial cell wall components and parasites) (e.g. Lu et al 2014;Nonaka 2014;Perdomo-Morales et al 2019). Lipopolysaccharide (LPS) from Gram-negative bacteria is a prime stimulant for PRCRs in animal eukaryotes, which sense the substance through tolllike receptors (TLRs) and trigger serum clotting, encapsulation, and coagulation.…”

Evaluation of anticoagulants and hemocyte-maintaining solutions for the study of hemolymph components in the spiny lobster Panulirus argus (Latreille, 1804) (Decapoda: Achelata: Palinuridae)

“…The hemocytes from the hemolymph of arthropods are the main players in both cellular and humoral immune response (Jiravanichpaisal et al, 2006). While the current model of coagulation in crustaceans is useful, significant departures from the model occur in different groups, mainly at the initiation stage of the process that involves the hemocytes (Perdomo-Morales et al, 2019). The ability to control the coagulation of plasma and hemocytes in crustacean species has fundamental and applied relevance.…”

“…Hemolymph clotting in crustaceans is mainly due to the polymerization of plasmatic clotting protein promoted by the hemocyte-derived transglutaminase enzyme (TGase) (Perdomo-Morales et al, 2019). Anticoagulant solutions are mostly based either in direct inhibition of TGase, or in the chelation of calcium ions required for TGase activity.…”