Microglia of medicinal leech (Hirudo medicinalis) express a specific activation marker homologous to vertebrate ionized calcium-binding adapter molecule 1 (Iba1/alias aif-1)
Research article published in Developmental neurobiology (2014)
Abstract
The Ionized calcium-Binding Adapter molecule 1 (Iba1), also known as Allograft Inflammatory Factor 1 (AIF-1), is a 17 kDa cytokine-inducible protein, produced by activated macrophages during chronic transplant rejection and inflammatory reactions in Vertebrates. In mammalian central nervous system (CNS), Iba1 is a sensitive marker associated with activated macrophages/microglia and is upregulated following neuronal death or brain lesions. The medicinal leech Hirudo medicinalis is able to regenerate its CNS after injury, leading to a complete functional repair. Similar to Vertebrates, leech neuroinflammatory processes are linked to microglia activation and recruitment at the lesion site. We identified a gene, named Hmiba1, coding a 17.8 kDa protein showing high similarity with Vertebrate AIF-1. The present work constitutes the first report on an Iba1 protein in the nervous system of an invertebrate. Immunochemistry and gene expression analyses showed that HmIba1, like its mammalian counterpart, is modulated in leech CNS by mechanical injury or chemical stimuli (ATP). We presently demonstrate that most of leech microglial cells migrating and accumulating at the lesion site specifically expressed the activation marker HmIba1. While the functional role of Iba1, whatever species, is still unclear in reactive microglia, this molecule appeared as a good selective marker of activated cells in leech and presents an interesting tool to investigate the functions of these cells during nerve repair events.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Summary
The Ionized calcium-Binding Adapter molecule 1 (Iba1), also known as Allograft Inflammatory Factor 1 (AIF-1), is a 17 kDa cytokine-inducible protein, produced by activated macrophages during chronic transplant rejection and inflammatory reactions in Vertebrates.
Why This Matters for Hirudotherapy
This study identified and characterized HmIba1, a leech homolog of the vertebrate ionized calcium-binding adapter molecule 1 (Iba1/AIF-1), demonstrating that it serves as a specific marker for microglial cells that migrate and accumulate at lesion sites in the CNS of Hirudo medicinalis after mechanical or chemical injury. This work is relevant to ASH's domain because it advances fundamental understanding of the medicinal leech's innate neuroimmune and regenerative biology—processes linked to the remarkable CNS repair capacity of this species. However, the study examines the leech's own nervous system and does not investigate leech salivary secretions, therapeutic bioactive compounds, or clinical outcomes of hirudotherapy. The authors note that the functional role of Iba1 remains unclear across species, and the findings primarily establish a research tool for future investigation rather than demonstrating direct therapeutic or mechanistic significance for leech therapy.
Citation
Microglia of medicinal leech (Hirudo medicinalis) express a specific activation marker homologous to vertebrate ionized calcium-binding adapter molecule 1 (Iba1/alias aif-1).
Drago F et al. · Developmental neurobiology, 2014
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