Identification and characterization of epicuticular proteins of nematodes sharing motifs with cuticular proteins of arthropods

C. elegans epicuticlins define specific compartments in the apical extracellular matrix and function in wound repair

The apical extracellular matrix (aECM) of external epithelia often contains lipid-rich outer layers that contribute to permeability barrier function. The external aECM of nematodes is known as the cuticle and contains an external lipid-rich layer - the epicuticle. Epicuticlins are a family of tandem repeat cuticle proteins of unknown function. Here, we analyze the localization and function of the three C. elegans epicuticlins (EPIC proteins). EPIC-1 and EPIC-2 localize to the surface of the cuticle near the outer lipid layer, as well as to interfacial cuticles and adult-specific struts. EPIC-3 is expressed in dauer larvae and localizes to interfacial aECM in the buccal cavity. Skin wounding in the adult induces epic-3 expression, and EPIC proteins localize to wound sites. Null mutants lacking EPIC proteins are viable with reduced permeability barrier function and normal epicuticle lipid mobility. Loss of function in EPIC genes modifies the skin blistering phenotypes of Bli mutants and reduces survival after skin wounding. Our results suggest EPIC proteins define specific cortical compartments of the aECM and promote wound repair.

In vitro anthelmintic activity of Phyllanthus niruri Linn., Andrographis paniculata, Curcuma xanthorrhiza Roxb., and Curcuma aeruginosa Roxb. ethanol extracts on the motility and cuticle damage of Ascaridia galli

Background and Aim

Ascaridia galli, a nematode that frequently infects the digestive tract of chickens, is a significant concern for poultry health. In response, the use of medicinal plant-derived anthelmintics was proposed as a potential solution. This study observed the in vitro effectiveness of a single, graded dose of the ethanol extract of Andrographis paniculata, Phyllanthus niruri L., Curcuma xanthorrhiza Roxb., and Curcuma aeruginosa Roxb. on the movement activity of adult A. galli every hour for 6 h, followed by an analysis of worm cuticle damage in A. galli.

Materials and Methods

A randomized block design was used. Adult A. galli were collected from the intestinal lumen of fresh free-range chickens. Each petri dish contained two A. galli for each treatment with three replications. Each plant extract (A. paniculata, P. niruri L., C. xanthorrhiza Roxb., and C. aeruginosa Roxb.) was evaluated with three distinct doses, which were 250 μg/mL, 500 μg/mL, and 1000 μg/mL; 0.9% sodium chloride solution was used as a negative control, and 500 μg/mL Albendazole solution was used as a positive control. The active compound content of A. paniculata, P. niruri L., C. xanthorrhiza Roxb., and C. aeruginosa Roxb. extracts were analyzed using ultra-performance liquid chromatography-mass spectrometry. The movement activity of A. galli was determined by the percentage score value from the 1st to the 6th h in each treatment group, followed by analysis of damage to the A. galli cuticle layer using a nano-microscope and histopathological images.

Results

Analysis of variance demonstrated that at doses of 250 μg/mL and 500 μg/mL, the ethanol extracts of A. paniculata, P. niruri L., C. xanthorrhiza Roxb., and C. aeruginosa Roxb. did not have a significant effect on the effectiveness of A. galli's motility (>0.005). However, at a dose of 1000 μg/mL, the ethanol extract of A. paniculata, P. niruri L., C. xanthorrhiza Roxb., and C. aeruginosa Roxb. reduced the motility of A. galli. Importantly, the motility of A. galli in the dose of 1000 μg/mL A. paniculata and P. niruri L. extract groups was very weak and significantly different (p < 0.001) compared to the negative control group. The content of the active compound Andrographolide in the ethanol extract of A. paniculata and the active compound 5-Methoxybenzimidazole in the extract of P. niruri L. are strongly suspected to play an important role in damaging and shedding the cuticle layer of A. galli.

Conclusion

All herbal extracts have anthelmintic activity at a concentration of 1000 μg/mL. Extracts of A. paniculata, P. niruri L., C. xanthorrhiza Roxb., and C. aeruginosa Roxb. have activities that can damage and dissolve the cuticle layer of A. galli, resulting in the weakening of the motility of A. galli.

The Caenorhabditis elegans cuticle and precuticle: a model for studying dynamic apical extracellular matrices in vivo

Apical extracellular matrices (aECMs) coat the exposed surfaces of animal bodies to shape tissues, influence social interactions, and protect against pathogens and other environmental challenges. In the nematode Caenorhabditis elegans, collagenous cuticle and zona pellucida protein-rich precuticle aECMs alternately coat external epithelia across the molt cycle and play many important roles in the worm's development, behavior, and physiology. Both these types of aECMs contain many matrix proteins related to those in vertebrates, as well as some that are nematode-specific. Extensive differences observed among tissues and life stages demonstrate that aECMs are a major feature of epithelial cell identity. In addition to forming discrete layers, some cuticle components assemble into complex substructures such as ridges, furrows, and nanoscale pillars. The epidermis and cuticle are mechanically linked, allowing the epidermis to sense cuticle damage and induce protective innate immune and stress responses. The C. elegans model, with its optical transparency, facilitates the study of aECM cell biology and structure/function relationships and all the myriad ways by which aECM can influence an organism.

C. elegans epicuticlins define specific compartments in the apical extracellular matrix and function in wound repair

The apical extracellular matrix (aECM) of external epithelia often contains lipid-rich outer layers that contribute to permeability barrier function. The external aECM of nematode is known as the cuticle and contains an external lipid-rich layer, the epicuticle. Epicuticlins are a family of tandem repeat proteins originally identified as components of the insoluble fraction of the cuticular aECM and thought to localize in or near epicuticle. However, there has been little in vivo analysis of epicuticlins. Here, we report the localization analysis of the three C. elegans epicuticlins (EPIC proteins) using fluorescent protein knock-ins to visualize endogenously expressed proteins, and further examine their in vivo function using genetic null mutants. By TIRF microscopy, we find that EPIC-1 and EPIC-2 localize to the surface of the cuticle in larval and adult stages in close proximity to the outer lipid layer. EPIC-1 and EPIC-2 also localize to interfacial cuticles and adult-specific cuticle struts. EPIC-3 expression is restricted to the stress-induced dauer stage, where it localizes to interfacial aECM in the buccal cavity. Strikingly, skin wounding in the adult induces epic-3 expression, and EPIC-3::mNG localizes to wound scars. Null mutants lacking one, two, or all three EPIC proteins display reduced survival after skin wounding yet are viable with low penetrance defects in epidermal morphogenesis. Our results suggest EPIC proteins define specific aECM compartments and have roles in wound repair.