Is Strongyloides stercoralis hyperinfection induced by glucocorticoids a result of both suppressed host immunity and altered parasite genetics?

Herbert, De’Broski R.; Stoltzfus, Jonathan D. C.; Rossi, Heather L.; Abraham, David

doi:10.1016/j.molbiopara.2022.111511

Cited by 7 publications

(3 citation statements)

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“…Similarly, GCs and parasite burden are generally positively linked on the short term in mammals (Defolie et al 2020). The underlying mechanisms of these associations could involve the impairing effects of GCs on host immunity and their supporting role in parasite development (Herbert et al 2022), but are not fully elucidated. While the immunosuppressive effects of GCs in chronically stressed individuals (Lee 2006, Martin 2009, Dhabhar 2014) and the consequences of acute stress-induced GC concentrations on individual performance (leading to the concept of ‘ emergency life-history stage ’, Wingfield et al 1998) have been investigated quite intensively using laboratory animal models, the consequences of elevated baseline GC levels (resulting from repeated or chronic stress exposure) on life-history traits are more equivocal ( e.g.…”

Section: Introductionmentioning

confidence: 99%

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Early-life glucocorticoids accelerate lymphocyte count senescence in roe deer

Lalande,

Bourgoin,

Carbillet

et al. 2024

Preprint

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Immunosenescence corresponds to the progressive decline of immune functions with increasing age. Although it is critical to understand what modulates such a decline, the ecological and physiological drivers of immunosenescence remain poorly understood in the wild. Among them, the level of glucocorticoids (GCs) during early life are good candidates to modulate immunosenescence patterns because these hormones can have long-term consequences on individual physiology. Indeed, GCs act as regulators of energy allocation to ensure allostasis, are part of the stress response triggered by unpredictable events and have immunosuppressive effects when chronically elevated. We used longitudinal data collected over two decades in two populations of roe deer (Capreolus capreolus) to test whether higher baseline GC levels measured within the first year of life were associated with a more pronounced immunosenescence and parasite susceptibility. We first assessed immunosenescence trajectories in these populations facing contrasting environmental conditions. We found no evidence that juvenile GC levels can modulate these trajectories except for lymphocytes for which depletion was accelerated late in life when FGMs were elevated early in life. Although the exact mechanism remains unknown, this result suggests a role of GCs in promoting T cells apoptosis and thymic involution. Adrenal GCs can also promote the production of thymic GCs, specifically amplifying the effects of GCs on lymphocyte compared to other immune traits. In addition, elevated GC levels in juveniles were associated with a higher abundance of lung parasites during adulthood for individuals born during bad years, suggesting short-term negative effects of GCs on juvenile immunity, having in turn long-lasting consequences on adult parasite load, depending on juvenile environmental conditions. These findings offer promising research directions in assessing the carry-over consequences of GCs on life-history traits in the wild.

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Section: Introductionmentioning

confidence: 99%

“…We thus expected individuals exhibiting higher levels of GCs during the juvenile stage to display earlier and/or accelerated immunosenescence due to the role of GCs in resource allocation. High GCs in juveniles were also expected to result in impaired immunity and enhanced parasite development during late life (Herbert et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Early-life glucocorticoids accelerate lymphocyte count senescence in roe deer

Lalande,

Bourgoin,

Carbillet

et al. 2024

Preprint

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“…In contrast, infections are often fatal in immunosuppressed individuals or individuals infected with certain viruses such as human T-lymphotropic virus 1 (HTLV-1) ( Nutman, 2017 ; Czeresnia and Weiss, 2022 ). In these cases, the population of parasites engaging in the autoinfective cycle can increase rapidly, leading to hyperinfection and disseminated strongyloidiasis ( Nutman, 2017 ; Czeresnia and Weiss, 2022 ; Herbert et al, 2022 ).…”

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confidence: 99%

Introduction to Strongyloides stercoralis Anatomy

Castelletto,

Akimori,

Patel

et al. 2024

Journal of Nematology

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Strongyloides stercoralis, commonly known as the human threadworm, is a skin-penetrating gastrointestinal parasitic nematode that infects hundreds of millions of people worldwide. Like other Strongyloides species, S. stercoralis is capable of cycling through a single free-living generation. Although S. stercoralis and the free-living nematode Caenorhabditis elegans are evolutionarily distant, the free-living adults of S. stercoralis are similar enough in size and morphology to C. elegans adults that techniques for generating transgenics and knockouts in C. elegans have been successfully adapted for use in S. stercoralis. High-quality genomic and transcriptomic data are also available for S. stercoralis. Thus, one can use a burgeoning array of functional genomic tools in S. stercoralis to probe questions about parasitic nematode development, physiology, and behavior. Knowledge gained from S. stercoralis will inform studies of other parasitic nematodes such as hookworms that are not yet amenable to genetic manipulation. This review describes the basic anatomy of S. stercoralis.

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