Cathepsins B1 and B2 in the neuropathogenic schistosome Trichobilharzia regenti: distinct gene expression profiles and presumptive roles throughout the life cycle

Abstract

The neurotropic bird schistosome Trichobilharzia regenti possesses papain-like cysteine peptidases which have also been shown to be crucial enzymes in various developmental stages of the related human parasites Schistosoma spp. In this paper, we present data obtained by real-time polymerase chain reaction on the temporal distribution of transcripts of two cathepsins in different developmental stages of T. regenti: cathepsin B1 originally described from the gut lumen of schistosomula with presumptive role in nutrient digestion and cathepsin B2 originally found in penetration glands of cercariae with probable involvement in invasion of the final host. In spite of their mutual resemblance at the sequence level, the mRNA expression profiles clearly show distinct expression of cathepsins B1 and B2 during the development from eggs to cercariae. In the case of both cathepsins, the highest level of transcription was detected in intravertebrate stages. Putative functions of cathepsins B1 and B2 in schistosome developmental stages are discussed.

Avian Schistosomes and Outbreaks of Cercarial Dermatitis

“…This enzyme was shown to cleave proteins of the host skin, similar to the case with S. japonicum (187,188). Its expression was even higher in intravertebrate stages (schistosomula and adults), suggesting that there are multiple roles of this enzyme during the life cycle (189). It seems that the use of particular peptidase families for skin penetration and tissue invasion is diverse among schistosomes (190) and may confer host specificity.…”

Nitric oxide and cytokine production by glial cells exposed in vitro to neuropathogenic schistosome Trichobilharzia regenti

“…These proteases are highly expressed in migrating schistosomula [50, 51] and can get in contact with the adjacent nervous tissue either when the parasite regurgitates (TrCB1.1 as a digestive enzyme, [18]) or when it struggles through the tissue (TrCB2 as a neurohistolytic enzyme, [13]). In our recent work [17] it remained questionable if secretions of schistosomula may be involved in the CNS pathogenesis, particularly in activation of glial cells.…”

Analysis of expressed sequence tags (ESTs) and gene expression changes under different growth conditions for the ciliate Anophryoides haemophila, the causative agent of bumper car disease in the American lobster (Homarus americanus)

“…This suggested that both cathepsin L and the two B homologs of A. haemophila may play roles in the mechanisms of host invasion and tissue degradation during infection. Alternatively, these proteases may be regulated by cell morphology or life cycle and therefore expression may be independent of host invasion (Doleckova et al, 2010). We evaluated these possibilities using real time RT-qPCR to observe changes in gene expression when A. haemophila was grown under different in vitro conditions and during a modified-in vivo infection of its natural host, the American lobster.…”