Molecular and expression analysis of the Allograft inflammatory factor 1 (AIF-1) in the coelomocytes of the common sea urchin Paracentrotus lividus

Characterization of microbiota and histology of cultured sea cucumber Isostichopus badionotus juveniles during an outbreak of skin ulceration syndrome

Due to the dramatic reduction of sea cucumber Isostichopus badionotus populations in the Yucatan Peninsula by overfishing and poaching, aquaculture has been encouraged as an alternative to commercial catching and restoring wild populations. However, the scarcity of broodstock, the emergence of a new disease in the auricularia larvae stage, and the development of skin ulceration syndrome (SUS) in the culture have limited aquaculture development. This study presents the changes in the intestine and skin microbiota observed in early and advanced stages of SUS disease in cultured juvenile I. badionotus obtained during an outbreak in experimental culture through 16S rRNA gene sequencing and histological evidence. Our results showed inflammation in the intestines of juveniles at both stages of SUS. However, more severe tissue damage and the presence of bacterial clusters were detected only in the advanced stages of SUS. Differences in the composition and structure of the intestinal and skin bacterial community from early and advanced stages of SUS were detected, with more evident changes in the intestinal microbial communities. These findings suggest that SUS was not induced by a single pathogenic bacterium. Nevertheless, a decrease in the abundance of Vibrio and an increase in Halarcobacter (syn. Arcobacter) was observed, suggesting that these two bacterial groups could be keystone genera involved in SUS disease.

Allograft inflammatory factor-1 stimulates inflammatory properties of peripheral blood leukocytes and increases cell viability via enhancing mitochondrial function in Ctenopharyngodon idellus

Allograft inflammatory factor-1 (AIF-1) is a 17 kDa calcium-binding protein associated with numerous inflammatory diseases. The full-length cDNA of AIF-1 has been identified in grass carp, Ctenopharyngodon idellus in our previous study, and it was assumed to be a novel molecule involved in immune responses. To clarify this aspect, the level of AIF-1 expression was amplified and reduced in grass carp peripheral blood leukocytes via transfection of vector pcDNA3.1-AIF1-EGFP and pLKO.1-shRNA-EGFP-puro, respectively. Thereafter, AIF-1 stimulated cell proliferation, inhibited cell apoptosis, which might benefit from improved mitochondrial function as evidenced by increased mitochondrial membrane potential, subsequently promoted ATP production. In addition, AIF-1 induced leukocyte migration via up-regulated monocyte chemotactic protein-1(MCP-1) secretion, enhanced neutral red uptake into leukocyte, provoked pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α), interleukin 1β (IL1β), interleukin 6 (IL6), interleukin 8 (IL8) and suppressed anti-inflammatory cytokine interleukin 10 (IL10) production. These results indicated AIF-1 played a critical role in grass carp innate immune system.

Allograft Inflammatory Factor-1 in Metazoans: Focus on Invertebrates

Simple Summary

During their life, all living organisms defend themselves from pathogens using complex strategies. Vertebrates and invertebrates share mechanisms and molecules that guarantee their overall bodily integrity. Allograft inflammatory factor-1 (AIF-1) is a protein extensively studied in vertebrates, and especially in mammals. This factor, generally involved in inflammation events occurring upon pathogenic infection or tissue injury, is linked to several important human diseases. This review collects data on the presence and role of AIF-1 in invertebrates, which are still poorly investigated organisms. Multiple alignment and phylogenetic analysis reveal that AIF-1 is conserved in vertebrates and invertebrates, suggesting similarity of functions. In some invertebrate species, the expression of AIF-1 increases considerably after a bacterial challenge, indicating that it plays a key role during the immune responses. This review highlights the importance of studying this protein in invertebrates as a way to improve our knowledge of innate immunity mechanisms and to better understand inflammatory regulation events in mammals.

Abstract

Allograft inflammatory factor-1 (AIF-1) is a calcium-binding scaffold/adaptor protein often associated with inflammatory diseases. Originally cloned from active macrophages in humans and rats, this gene has also been identified in other vertebrates and in several invertebrate species. Among metazoans, AIF-1 protein sequences remain relatively highly conserved. Generally, the highest expression levels of AIF-1 are observed in immunocytes, suggesting that it plays a key role in immunity. In mammals, the expression of AIF-1 has been reported in different cell types such as activated macrophages, microglial cells, and dendritic cells. Its main immunomodulatory role during the inflammatory response has been highlighted. Among invertebrates, AIF-1 is involved in innate immunity, being in many cases upregulated in response to biotic and physical challenges. AIF-1 transcripts result ubiquitously expressed in all examined tissues from invertebrates, suggesting its participation in a variety of biological processes, but its role remains largely unknown. This review aims to present current knowledge on the role and modulation of AIF-1 and to highlight its function along the evolutionary scale.

Studying the effects of sea cucumber ovum powder on nonalcoholic fatty liver disease by proteomics techniques in a rat model

Sea cucumber is a valuable marine food that has antioxidant, anti-diabetic, and anti-obesity functionalities. Sea cucumber ovum (SCO) may contain functional components, however, it is considered to be a waste product during industrial processing. In order to make good use of SCO, this work investigated the effects of freeze-dried SCO powder on NAFLD, using a rat model, through iBT labeling proteomics techniques, tracking changes in the hepatic protein profiles of rats whose diets were supplemented with SCO powder. Male rats were fed with standard food, a high fat diet (HFD), or a HFD supplemented with 150 mg per kg BW or 450 mg per kg BW SCO powder for 6 weeks. Compared with the HFD, low-dose SCO supplementation in the diet could significantly reduce body weight gain and liver weight. Furthermore, in total, 5922 proteins were identified, and 767 proteins were found to be significantly different proteins (p < 0.05) among all four groups. Most of the significantly different proteins were related to apoptosis and lipid metabolism. Fadd, Dci, and Aif1 have been identified as key proteins in the pathways related to apoptosis, lipid metabolism, and inflammation. The results in this study provide an overview of the SCO-induced changes in the liver proteome of NAFLD, which may help us to understand the molecular mechanism behind the effects of SCO on the alleviation of NAFLD.

Methods for collection, handling, and analysis of sea urchin coelomocytes

Sea urchin coelomocytes can be collected in large numbers from adult sea urchins of the species, Strongylocentrotus purpuratus, which typically has 12-40mL of coelomic fluid. Coelomocytes are used for analysis of immune reactions and immune gene expression in addition to basic functions of cells, in particular for understanding structure and modifications of the cytoskeleton in phagocytes. The methods described here include coelomocyte isolation, blocking the clotting reaction, establishing and maintaining primary cultures, separation of different types of coelomocytes into fractions, processing live coelomocytes for light microscopy, fixation and staining for light and electron microscopy, analysis of coelomocyte populations by flow cytometry, and sorting single cells for more detailed follow-up analyses including transcriptomics or genomic characteristics. These methods are provided to make working with coelomocytes accessible to researchers who are unfamiliar with these cells and perhaps to aid others who have worked extensively with invertebrate cells.