Peptidylarginine Deiminase inhibition abolishes the production of large extracellular vesicles fromGiardia intestinalis, affecting host-pathogen interactions by hindering adhesion to host cells

Abstract

Giardia intestinalis is an anaerobic protozoan that is an important etiologic agent of inflammation-driven diarrhea worldwide. Although self-limiting, a deep understanding of the factors involved in the pathogenicity that produces the disruption of the intestinal barrier remains unknown. There is evidence that under diverse conditions, the parasite is capable of shedding extracellular vesicles (EVs) which could modulate the physiopathology of giardiasis. Here we describe new insights of G. intestinalis EV production, revealing its capacity to shed two different enriched EV populations (large and small extracellular vesicles) and identified a relevant adhesion function associated only with the larger population. Our work also aimed at assessing the influences of two recently identified inhibitors of EV release in mammalian cells, namely peptidylarginine deiminase (PAD) inhibitor and cannabidiol (CBD), on EV release from Giardia and their putative effects on host-pathogen interactions. PAD-inhibitor Cl-amidine and CBD were both able to effectively reduce EV shedding, the PAD-inhibitor specifically affecting the release of large extracellular vesicles and interfering with in vitro host-pathogen interactions. The strong efficacy of the PAD-inhibitor on Giardia EV release indicates a phylogenetically conserved pathway of PAD-mediated EV release, most likely affecting the Giardia arginine deiminase (GiADI) homolog of mammalian PADs. While there is still much to learn about G. intestinalis interaction with its host, our results suggest that large and small EVs may be differently involved in protozoa communication, and that EV-inhibitor treatment may be a novel strategy for recurrent giardiasis treatment.

Protein Deimination and Extracellular Vesicle Profiles in Antarctic Seabirds

“…Protein deimination can affect gene regulation and cause generation of neo-epitopes [5,12] but may also allow for protein moonlighting, facilitating several physiologically relevant functions from within one polypeptide chain [13,14]. PADs have been identified in diverse taxa from bacteria to mammals, with five tissue-specific PAD isozymes in mammals, three in the chicken Gallus gallus domesticus, one in bony fish [1,6,7,15,16] and PAD homologues in bacteria, protozoa and fungi [17][18][19][20]. Although PADs are well known to have pathophysiological roles in cancer, autoimmune and central nervous system (CNS) diseases [4,5,12,16,21,22], much less is known about their involvement in physiological processes.…”

“…PADs play crucial roles in the cellular release of extracellular vesicles (EVs) in diverse taxa [18,19,[25][26][27]. EVs are found in most body fluids and participate in cellular communication via transfer of cargo proteins and genetic material [5,[28][29][30][31].…”

Deiminated proteins in extracellular vesicles and serum of llama (Lama glama)—Novel insights into camelid immunity

“…As PADs have been identified to be a key regulator of extracellular (EV)-release, a mechanism that has been found to be phylogenetically conserved from bacteria to mammals (Kholia et al, 2015;Kosgodage et al, 2017Kosgodage et al, , 2018Gavinho et al, 2019;Kosgodage et al, 2019), the characterisation of EVs in camelids is of further interest. Extracellular vesicles (EVs) are found in most body fluids and participate in cellular communication via transfer of cargo proteins and genetic material (Inal et al, 2013;Colombo et al, 2014;Lange et al, 2017;Turchinovich et al, 2019;Vagner et al, 2019).…”

“…EVs in body fluids, including serum, can also be useful biomarkers to reflect health status (Hessvik and Llorente, 2018;Ramirez et al, 2018). Previous work on EVs has hitherto mainly been in the context of human pathologies, while recently comparative studies are growing (Iliev et al, 2018;Yang et al, 2015;Magnadóttir et al, 2019b;Criscitiello et al, 2019;Gavinho et al, 2019;Kosgodage et al, 2019). Few studies have been performed on EVs in camelids but therapeutic effects of EVs isolated from camel milk have been identified in halting cancer progression (Badawy et al, 2018).…”

“…Previous studies on EVs in camelids focussed on EVs in camel milk, which were shown to have anti-cancerous properties (Badawy et al, 2018). As PADs have been identified to play major roles in the regulation of EV release (Kholia et al, 2015;Kosgodage et al, 2017 and, including in host-pathogen interactions (Gavinho et al, 2019), such EV-mediated communication may be of great relevance also for addressing diverse zoonotic diseases identified in camels (El-Alfy et al, 2019;Zhu et al, 2019).…”