Molecular cloning and transcriptional regulation of an allograft inflammatory factor-1 (AIF-1) in Zhikong scallop Chlamys farreri

LC-MS/MS based characterisation and differential expression of proteins in Himalayan snow trout, Schizothorax labiatus using LFQ technique

Molecular characterization of fish muscle proteins are nowadays considered as a key component to understand the role of specific proteins involved in various physiological and metabolic processes including their up and down regulation in the organisms. Coldwater fish specimens including snow trouts hold different types of proteins which help them to survive in highly diversified temperatures fluctuating from 0 to 20 °C. So, in current study, the liquid chromatography mass spectrometry using label free quantification technique has been used to investigate the muscle proteome profile of Schizothorax labiatus. For proteomic study, two weight groups of S. labiatus were taken from river Sindh. The proteomic analysis of group 1 revealed that a total of 235 proteins in male and 238 in female fish were recorded. However, when male and female S. labiatus were compared with each other on the basis of spectral count and abundance of peptides by ProteinLynx Global Server software, a total of 14 down-regulated and 22 up-regulated proteins were noted in this group. The highly down-regulated ones included homeodomain protein HoxA2b, retinol-binding protein 4, MHC class II beta chain and proopiomelanocortin while as the highly expressed up-regulated proteins comprised of gonadotropin I beta subunit, NADH dehydrogenase subunit 4, manganese superoxide dismutase, recombinase-activating protein 2, glycosyltransferase, chymotrypsin and cytochrome b. On the other hand, the proteomic characterisation of group 2 of S. labiatus revealed that a total of 227 proteins in male and 194 in female fish were recorded. When male and female S. labiatus were compared with each other by label free quantification, a total of 20 down-regulated and 18 up-regulated proteins were recorded. The down-regulated protein expression of group 2 comprised hepatic lipase, allograft inflammatory factor-1, NADH dehydrogenase subunit 4 and myostatin 1 while the highly expressed up-regulated proteins included glycogen synthase kinase-3 beta variant 2, glycogen synthase kinase-3 beta variant 5, cholecystokinin, glycogen synthase kinase-3 beta variant 3 and cytochrome b. Significant (P < 0.05) difference in the expression of down-regulated and up-regulated proteins was also noted between the two sexes of S. labiatus in each group. According to MS analysis, the proteins primarily concerned with the growth, skeletal muscle development and metabolism were down-regulated in river Sindh, which indicates that growth of fish during the season of collection i.e., winter was slow owing to less food availability, gonad development and low metabolic activity. While, the proteins related to immune response of fish were also noted to be down-regulated thereby signifying that the ecosystem has less pollution loads, microbial, pathogenic and anthropogenic activities. It was also found that the proteins involved in glycogen metabolism, reproductive and metabolic processes, particularly lipid metabolism were up-regulated in S. labiatus. The significant expression of these proteins may be connected to pre-spawning, gonad development and use of stored food as source of energy. The information generated in this study can be applied to future research aimed at enhancing food traceability, food safety, risk management and authenticity analysis.

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.

Scallop IKK1 Responds to Bacterial and Virus-Related Pathogen Stimulation and Interacts With MyD88 Adaptor of Toll-Like Receptor Pathway Signaling

IKK proteins are key signaling molecules in the innate immune system of animals, and act downstream of pattern recognition receptors. However, research on IKKs in invertebrates, especially marine mollusks, remains scarce. In this study, we cloned CfIKK1 gene from the Zhikong scallop (Chlamys farreri) and studied its function and the signaling it mediates. The open reading frame of CfIKK1 was 2190 bp and encoded 729 amino acids. Phylogenetic analysis showed that CfIKK1 belonged to the invertebrate IKKα/IKKβ family. Quantitative real-time PCR analysis revealed the ubiquitous expression of CfIKK1 mRNA in all scallop tissues and challenge with lipopolysaccharide, peptidoglycan, or poly(I:C) significantly upregulated the expression of CfIKK1. Co-immunoprecipitation assays confirmed the interaction of CfIKK1 with scallop MyD88 (Myeloid differentiation actor 88, the key adaptor of the TLR signaling pathway) via its N-terminal kinase domain. Additionally, CfIKK1 protein could form homodimers and even oligomers, with N-terminal kinase domain and C-terminal scaffold dimerization domain playing key roles in this process. Finally, the results of RNAi experiments showed that when the scallop IKK1 gene was suppressed, the expression of IRF genes also decreased significantly. In conclusion, CfIKK1 could respond to PAMPs challenge and interact with MyD88 protein of scallop TLR signaling, with the formation of CfIKK1 dimers or oligomers. At the same time, the results of RNAi experiments revealed the close regulatory relationship between IKK1 and IRF genes of scallop. Therefore, as a key signal transduction molecule and immune activity regulator, CfIKK1 plays important roles in the innate immune system of scallops.

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.

iTRAQ-based quantitative proteomic profiling of the immune response of the South African abalone, Haliotis midae

The South African abalone Haliotis midae is a commercially important species farmed at high densities in land-based aquaculture systems. Disease outbreaks have had a severe financial impact on the abalone industry yet the molecular mechanisms underlying the immune response of H. midae remain obscure. In this study, a comparative shotgun proteomics approach using iTRAQ coupled with LC-MS/MS was employed to investigate H. midae proteome changes in response to Vibrio anguillarum challenge. A total of 118 non-redundant, unique haemocyte proteins were identified and quantified, with 16 proteins significantly regulated. Hierarchical clustering and pathway analysis uncovered a coordinated response dominated by calcium and cAMP signalling via activation of MAPK cascades. Early up-regulated biological processes involve phagocytosis, nitric oxide production and ATP-synthesis, whilst down-regulated responses were predominantly involved in the regulation of apoptosis. The late up-regulated response involved protein kinase activity and detoxification processes. Expression of selected proteins was validated by Western blot. A putative allograft inflammatory factor-1 protein was further selected to establish its functional molecular role in haemocytes. Confocal imaging revealed that allograft inflammatory factor-1 regulates phagocytosis via a functional interaction with filamentous actin. This is the first time a high-throughput proteomics approach has been used to investigate the immune response of H. midae.

Some Galeomorph Sharks Express a Mammalian Microglia-Specific Protein in Radial Ependymoglia of the Telencephalon

Ionized calcium-binding adapter molecule 1 (Iba1), also known as allograft inflammatory factor 1 (AIF-1), is a highly conserved cytoplasmic scaffold protein. Studies strongly suggest that Iba1 is associated with immune-like reactions in all Metazoa. In the mammalian brain, it is abundantly expressed in microglial cells and is used as a reliable marker for this cell type. The present study used multiple-label microscopy and Western blotting to examine Iba1 expression in the telencephalon of 2 galeomorph shark species, the swellshark (Cephaloscyllium ventriosum) and the horn shark (Heterodontus francisci), a member of an ancient extant order. In the swellshark, high Iba1 expression was found in radial ependymoglial cells, many of which also expressed glial fibrillary acidic protein. Iba1 expression was absent from most cells in the horn shark (with the possible exception of perivascular cells). The difference in Iba1 expression between the species was supported by protein analysis. These results suggest that radial ependymoglia of the elasmobranchs may be functionally related to mammalian microglia and that Iba1 expression has undergone evolutionary changes in this cartilaginous group.

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

Allograft inflammatory factor 1 (AIF-1) is a highly conserved gene involved in inflammation, cloned and characterized in several evolutionary distant animal species. Here, we report the molecular identification, characterization and expression of AIF-1 from the common sea urchin Paracentrotus lividus. In this species, AIF-1 encodes a predicted 151 amino acid protein with high similarity to vertebrate AIF-1 proteins. Immunocytochemical analyses on coelomocytes reveal localization of the AIF-1 protein in amoebocytes (perinuclear cytoplasmic zone) and red sphaerulocytes (inside granules), but not in vibratile cells and colorless sphaerula cells. The significant increase of AIF-1 expression (mRNA and protein) found in the coelomocytes of the sea urchin after Gram + bacterial challenge suggests the involvement of AIF-1 in the inflammatory response. Our analysis on P. lividus AIF-1 contributes to elucidate AIF-1 function along the evolutionary scale and consolidate the key evolutionary position of echinoderms throughout metazoans with respect to the common immune paths.

Characterization of allograft inflammatory factor-1 in Hyriopsis cumingii and its expression in response to immune challenge and pearl sac formation

The allograft inflammatory factor-1 (AIF-1) is one of the key factors associated with inflammatory response and immune defense. In the present study, we report the identification and characterization of AIF-1 from triangle sail mussel Hyriopsis cumingii (HcAIF-1). The full-length cDNA of HcAIF-1 consisted of a 5'-terminal untranslated region (UTR) of 80 bp, a 3'-UTR of 420 bp with a poly (A) tail, and an open reading frame of 444 bp encoding a polypeptide of 147 amino acids with two conserved EF-hand Ca²⁺-binding motifs. HcAIF-1 mRNA and protein were expressed in all examined tissues and showed higher mRNA expression levels were observed in immune tissues, especially hemocytes and mantle, and the highest protein expression level was in mantle. The expression level of HcAIF-1 mRNA was significantly upregulated in hemocytes 12-48 h after lipopolysaccharide challenge. After mantle tissue implantation, the expression level of this gene in pearl sac decreased significantly at 3-48 h (P < 0.01), and then was significantly upregulated at 96 h (P < 0.05) and recovered to the control level at 21-28 d. There was significant increase HcAIF-1 transcript abundance in hemocytes 96 h (P < 0.05) after mantle tissue implantation. The phagocytosis rate was significantly enhanced in hemocytes 3-24 h (P < 0.01) after the injection of recombinant HcAIF-1 protein. These findings suggest that HcAIF-1 is important in the underlying mechanism of the innate immune responses and pearl sac formation of H. cumingii.

Allograft inflammatory factor-1 in grass carp (Ctenopharynogodon idella): Expression and response to cadmium exposure

Allograft Inflammatory Factor-1 (AIF-1) is an inflammation responsive protein that is mainly produced by immunocytes. As a pro-inflammatory cytokine, AIF-1 is a key moderator in host immune defense reaction. However, the inflammatory properties of AIF-1 in freshwater fish still hasn't been clearly elucidated. In the present study, AIF-1 was identified from grass carp (Ctenopharynogodon idella). It's transcript was found in all examined tissues including brain, spleen, kidney, liver, heart, while a relative low level in red muscle, gill, thymus, white muscle, intestine and fin. Furthermore, AIF-1 transcription and expression level decreased in spleen and didn't change a lot in kidney with cadmium induction, respectively. The result indicated that grass carp AIF-1 might be involved in cadmium-induced stress.

The immune system and its modulation mechanism in scallop

Scallops are a cosmopolitan family of bivalves, and some of them are highly prized as dominant aquaculture species. In the past decades, there have been increasing studies on the basic biology and immunology of scallops, and this review summarizes the research progresses of immune system and its modulation mechanism in scallop. As invertebrate, scallops lack adaptive immunity and they have evolved an array of sophisticated strategies to recognize and eliminate various invaders by employing a set of molecules and cells. It is evident that basic immune reactions such as immune recognition, signal transduction, and effector synthesis involved in immune response are accomplished in a variety of ways. They rely upon an extensive repertoire of phagocytosis, apoptosis and encapsulation of the circulating hemocytes for eliminating invasive pathogens, as well as the production of immune effectors that are active against a large range of pathogens or sensitive for the environmental stress. Furthermore, the molecular constitutions, metabolic pathways and immunomodulation mechanisms of the primitive catecholaminergic, cholinergic, enkephalinergic system and NO system in scallop are also discussed, which can be taken as an entrance to better understand the origin and evolution of the neuroendocrine-immune regulatory network in lower invertebrates.

Molecular characterization and immune response expression of the QM gene from the scallop Chlamys farreri

The scallop Chlamys farreri is an important aquaculture species in northern China. However, the sustainable development of the scallop industry is currently threatened by several pathogens that cause mass mortality of this mollusk. Therefore, a complete understanding of the immune response mechanisms involved in host-virus interactions is necessary. This study reports a novel QM gene from C. farreri. This gene was first identified as a putative tumor suppressor gene from human and then confirmed to participate in several functions, including immune response. The QM gene from C. farreri (CfQM) was identified by suppression subtractive hybridization, and its full-length (763 bp) cDNA was obtained through rapid amplification of cDNA ends. The cDNA of CfQM contained a short 5'-UTR of 22 bp and a 3'-UTR of 84 bp. Its ORF comprised 657 nucleotides that encode 218 amino acids with a molecular weight of approximately 28.3 kDa and an isoelectric point of 10.06. The deduced amino acid sequence of CfQM contained a series of conserved functional motifs that belong to the QM family. Phylogenetic analysis revealed that CfQM was closely related to other mollusk QM proteins, and altogether they form a mollusk QM protein subfamily that displays evolutionary conservation from yeast to human. The tissue-specific expression and transcriptional regulation of CfQM were investigated by quantitative real-time PCR in response to bacterial (Vibrio anguillarum) and viral (acute viral necrobiotic virus) challenges. The transcript level of CfQM was high in all of the examined tissues in a constitutive manner. The highest and lowest expression levels of CfQM were measured in the hepatopancreas and hemocyte, respectively. Upon bacterial and viral challenges, the relative mRNA expression of CfQM sharply increased at 6 h post-infection (hpi) and then normalized at 48 hpi. These findings suggest that CfQM can respond to and protect against pathogen challenge. To the best of our knowledge, this study is the first report of the QM gene from scallop. The results presented herein provided new insights into the molecular basis of host-pathogen interactions in C. farreri.