Planarians to schistosomes: an overview of flatworm cell-types and regulators

Abstract

Schistosomiasis remains a major neglected tropical disease that afflicts over 200 million people globally. Schistosomes, the aetiological agent of schistosomiasis, are parasitic flatworms that propagate between molluscan and mammalian hosts. Inside the mammalian host, schistosomes rapidly grow over 100-fold in size and develop into a sexually mature male or female that thrives in the bloodstream for several decades. Recent work has identified schistosome stem cells as the source that drives parasite transmission, reproduction and longevity. Moreover, studies have begun to uncover molecular programmes deployed by stem cells that are essential for tissue development and maintenance, parasite survival and immune evasion. Such programmes are reminiscent of neoblast-driven development and regeneration of planarians, the free-living flatworm relative of schistosomes. Over the last few decades, research in planarians has employed modern functional genomic tools that significantly enhanced our understanding of stem cell-driven animal development and regeneration. In this review, we take a broad stroke overview of major flatworm organ systems at the cellular and molecular levels. We summarize recent advances on genetic regulators that play critical roles in differentiation and maintenance of flatworm cell types. Finally, we provide perspectives on how investigation of basic parasite biology is critical to discovering new approaches to battle schistosomiasis.

Conserved Genes in Highly Regenerative Metazoans Are Associated with Planarian Regeneration

“…Fork head/winged helix TFs have previously been identified to be crucial in anterior pole regeneration ( Scimone et al 2014 ). It has been shown that C2H2 zinc finger factors play a role in neoblast maintenance and homeostasis ( Lee 2023 ). These reports on TFs related to development and regeneration suggest that HRA genes could be involved in the molecular mechanisms of the regenerative process.…”