Cell adhesion and the immune system: a case study using earthworms

In vitro cytotoxic and apoptotic induction effect of earthworm coelomic fluid of Eudrilus eugeniae, Eisenia foetida, and Perionyx excavatus on human oral squamous cell carcinoma-9 cell line

The current protocol of cancer management includes surgery, radiotherapy and chemotherapy. However, these modalities have significant adverse effects and affect the quality of life. Further intensification of treatment is hindered as maximal toxicity levels are reached impeding improvement. Hence researchers are in the quest for adjunctive naturally available therapies that can alter tumor proliferation without causing significant adverse reactions. The present study aims to explore the cytotoxic potential of earthworm coelomic fluid (ECF) of Eudrilus eugeniae (EE), Eisenia foetida (EF), and Perionyx excavatus (PE) on oral cancer cell line SCC-9. The effect of ECF on cell cycle analysis and mechanism of cell death have also been investigated. All experiments reported in this paper were performed as 3 replicates per experiment. The results indicated that ECF of EE, EF and PE have potent variable cytotoxic effect on SCC-9 cells demonstrated through LDH, clonogenic and comet assay. An effective cell cycle arrest was observed at the G2M phase of cell cycle with apoptotic induction that was observed through an Annexin V - FITC/PI assay. ECF of EE was found to be superior in its cytotoxic action closely followed by ECF of PE. The present findings provide evidence for the first time that ECF of EE, EF and PE have potent cytotoxic effect on oral cancer cells in vitro. They significantly induce G2M cell cycle arrest and promote apoptosis in SCC-9 cell line. Gene expression studies have been planned to ascertain the pathways of cell death.

Environmental pollutants, pathogens and immune system in earthworms

Earthworms also known as farmer's friends are natural tillers of soil. They belong to Phylum Annelida and class Oligochaeta. Acid soils with organic matter and surface humus maintain the largest fauna of worms and earthworms. Due to their habitat in soil, they are constantly exposed to microbes and pollution generated by anthropogenic sources. Studies have revealed that damage of the immune system of earthworms can lead to alterations of both morphological and cellular characteristics of worms, activation of signalling pathways and can strongly influence their survival. Therefore, the understanding of the robust immune system in earthworms has become very important from the point of view of understanding its role in combating pathogens and pollutants and its role in indicating the soil pollution. In this article, we have outlined the (i) components of the immune system and (ii) their function of immunological responses on exposure to pollutants and pathogens. This study finds importance from the point of view of ecotoxicology and monitoring of earthworm health and exploring the scope of earthworm immune system components as biomarkers of pollutants and environmental toxicity. The future scope of this review remains in understanding the earthworm immunobiology and indicating strong biomarkers for pollution.

In vitro Antiproliferative Effect of Earthworm Coelomic Fluid of Eudrilus Eugeniae, Eisenia Foetida, and Perionyx Excavatus on Squamous Cell Carcinoma-9 Cell Line: A Pilot Study

Introduction

The earthworm coelomic fluid (ECF) has shown proven antiproliferative effect against breast, liver, gastrointestinal, and brain cancer, but it is least explored in oral cancer. The present in vitro study is an attempt to investigate the antiproliferative activity of ECF on oral cancer cell line squamous cell carcinoma (SCC)-9.

Materials and Methods

ECF was collected from the species Eudrilus eugeniae (EE), Eisenia foetida (EF), and Perionyx excavatus (PE) stored at -80°C. Percentage inhibition of ECF on squamous cell carcinoma-9 cells in vitro was recorded at 24 h. Protein estimation was done using Bradford protein assay validated by the biuret method. Cytotoxicity was tested at 2.5, 5, 10, 20, 40, and 80 μg/ml concentrations by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay in SCC-9 cells in vitro. GraphPad Prism 7.0 software was used to calculate the inhibitory concentration (IC₅₀). Chi-square test was used to analyze the difference between samples.

Results

The test samples EE, EF, and PE inhibited the growth of SCC-9 cells significantly in a dose-dependent manner, and the IC₅₀ values were found to be 4.6, 44.69, and 5.27 μg/ml, respectively. The antiproliferative effect was found to be variable among the three earthworm species with EE showing the most promising effect followed by PE and EF.

Conclusion

Establishing the antiproliferative effect of ECF on oral cancer cells could be an initial step toward drug development and future anticancer research. The preliminary investigation has shown that ECF has a promising antiproliferative effect on oral cancer cells in vitro.

SUMMARY

The present pilot study evaluated the in vitro antiproliferative effect of earthworm coelomic fluid (ECF) of Eudrilus eugeniae (EE), Eisenia foetida (EF), and Perionyx excavatus (PE) on squamous cell carcinoma-9 cell line. The ECF inhibitory activity was promising at inhibitory concentration values of 4.6, 44.69, and 5.27 μg/ml, respectively. Further studies pertaining to antiproliferative mechanism of EE, EF, and PE have been planned.Abbreviations Used: ECF: Earthworm coelomic fluid, EE: Eudrilus eugeniae, EF: Eisenia foetida, PE: Perionyx excavatus, MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, SCC: Squamous cell carcinoma, BSA: Bovine serum albumin, PBS: Phosphored buffered saline, ATCC: American Type Culture Collection.

Evolution of vertebrate adaptive immunity: immune cells and tissues, and AID/APOBEC cytidine deaminases

All surviving jawed vertebrate representatives achieve diversity in immunoglobulin-based B and T cell receptors for antigen recognition through recombinatorial rearrangement of V(D)J segments. However, the extant jawless vertebrates, lampreys and hagfish, instead generate three types of variable lymphocyte receptors (VLRs) through a template-mediated combinatorial assembly of different leucine-rich repeat (LRR) sequences. The clonally diverse VLRB receptors are expressed by B-like lymphocytes, while the VLRA and VLRC receptors are expressed by lymphocyte lineages that resemble αβ and γδ T lymphocytes, respectively. These findings suggest that three basic types of lymphocytes, one B-like and two T-like, are an essential feature of vertebrate adaptive immunity. Around 500 million years ago, a common ancestor of jawed and jawless vertebrates evolved a genetic program for the development of prototypic lymphoid cells as a foundation for an adaptive immune system. This acquisition preceded the convergent evolution of alternative types of clonally diverse receptors for antigens in all vertebrates, as reviewed in this article.

Cytotoxicity and fibroblast properties during in vitro test of biphasic calcium phosphate/poly-dl-lactide-co-glycolide biocomposites and different phosphate materials

Reconstruction of bone defects is one of the major therapeutic goals in various clinical fields. Bone replacement materials must satisfy a number of criteria. Biological criteria are biocompatibility, controlled biodegradability, and osteoconductive or even osteogenic potential. The material should have a three-dimensional structure with an interconnected pore system so as to permit cell growth and transport of substances. The surface must permit cell adhesion and proliferation. Composite biomaterials have enormous potential for natural bone tissue reparation, filling and augmentation. Calcium hydroxyapatite/polymer composite biomaterials belong to this group of composites and, because of their osteoconductive and biocompatible properties, can be successfully implemented within bone tissue reparations. In this study, possible differences between BCP/DLPLG, pure BCP, and Bio-Oss materials were examined in vitro. During overnight incubations, fibroblast and fibroblast-like cells (L929, MRC5) were able to adhere, spread, and remain viable on BCP, BCP/PLGA, and Bio-Oss discs, as was evidenced by using light- and LVSEM-microscopy. Inhibiting influence over the cell growth is more pronounced in the cases of BCP usage on both cell lines--41.29% for L929 and 43.08% for MRC-5 cells. MRC-5 cells are, within the given experimental conditions, less sensitive on inhibiting effects for the materials BCP/PLGA and Bio-Oss (10.13% and 10.76%, respectively) than for the L929 cell lines (23.02% and 15.44%, respectively).

Anticipating innate immunity without a Toll

Earthworm innate immunity depends upon small and large leukocytes (coelomocytes) that synthesize and secrete humoral antimicrobial molecules (e.g. lysenin, fetidin, eiseniapore, coelomic cytolytic factor [CCF]; Lumbricin I). Small coelomocytes (cytotoxic) are positive (CD11a, CD45RA, CD45RO, CDw49b, CD54, beta(2)-m and Thy-1 [CD90]; CD24; TNF-alpha) but negative using other mammalian markers. Large coelomocytes (phagocytic) are uniformly negative. Specific earthworm anti-EFCC 1, 2, 3, 4 mAbs are negative for Drosophila melanogaster hemocytes and mammalian cells but positive those of earthworms. Coelomocytes contain several lysosomal enzymes involved in phagocytosis and a pattern recognition molecule (CCF) that may trigger the prophenoloxidase cascade a crucial innate immune response. Earthworms and other invertebrates possess natural, non-specific, non-clonal, and non-anticipatory immune response governed by germ line genes. Toll and Toll-like receptor signaling is essential for phagocytosis and antimicrobial peptide synthesis and secretion in insects and vertebrates but has not yet been shown to be essential in earthworm innate responses.

Monoclonal antibodies identify four distinct annelid leukocyte markers

This paper describes for the first time the production and characterization of a library of monoclonal antibodies (anti-EFCC clones) raised against coelomocyte (leukocyte) markers of Eisenia fetida earthworm. Leukocyte subgroups are components of earthworm innate immunity that require a more precise characterization using immunological markers. Flow cytometry, immunocytochemistry, and immunoprecipitation analyzed and confirmed the specificity of anti-EFCC clones. Anti-EFCC mAbs revealed different leukocyte subpopulations and various staining patterns on tissues. Two functional assays (e.g. phagocytosis and encapsulation) further characterized EFCC clusters revealing a common coelomocyte marker and three subpopulation-specific markers. No crossreactivity was found on human, mouse, rat or cells from Drosophila melanogaster but immunoreactivity was detected on snail (Planorbarius corneus) tissues. Immunohistochemical results suggest mesodermal origin of all coelomocyte subgroups that agree with classical morphological analyses.

DIFFERENTIAL PROPAGATION OF THE METAZOAN PARASITE MYXOBOLUS CEREBRALIS BY LIMNODRILUS HOFFMEISTERI, ILYODRILUS TEMPLETONI, AND GENETICALLY DISTINCT STRAINS OF TUBIFEX TUBIFEX

Whirling disease, caused by the parasite Myxobolus cerebralis, has infected rainbow trout (Oncorhynchus mykiss) and other salmonid fish in the western United States, often with devastating results to native populations but without a discernible spatial pattern. The parasite develops in a complex 2-host system in which the aquatic oligochaete Tubifex tubifex is an obligate host. Because substantial differences in whirling disease severity in different areas of North America did not seem explainable by environmental factors or features of the parasite or its fish host, we sought to determine whether ecological or genetic variation within oligochaete host populations may be responsible. We found large differences in compatibility between the parasite and various laboratory strains of T. tubifex that were established from geographic regions with different whirling disease histories. Moreover, 2 closely related species of tubificids, Limnodrilus hoffmeisteri and Ilyodrilus templetoni, which occur naturally in mixed species assemblages with T. tubifex, were incompatible with M. cerebralis. Virulence of the parasite was directly correlated with the numbers of triactinomyxon spores that developed within each strain of T. tubifex. Thus, the level of virulence was directly related to the compatibility between the host strain and the parasite. Genetic analyses revealed relationships that were in agreement with the level of parasite production. Differences in compatibilities between oligochaetes and M. cerebralis may contribute to the spatial variance in the severity of the disease among salmonid populations.

Digging for innate immunity since Darwin and Metchnikoff

Immune systems are, increasingly, being studied from comparative perspectives. The analysis of the immune-defense systems of invertebrates, such as fruit flies and earthworms, is an important part of this effort. These systems are innate, natural non-specific, non-anticipatory and non-clonal. This is in contrast to the macrophage T and B systems that characterize vertebrate adaptive immunity whose properties can be categorized as adaptive, induced, specific, anticipatory, and clonal. In this review, we will focus on the earthworm system. Earthworms, like other complex invertebrates, possess several leukocyte types and synthesize and secrete a variety of immunoprotective molecules. The system as a whole effects phagocytosis, encapsulation, agglutination, opsonization, clotting and lysis of foreign components. At least two major leukocytes, small coelomocytes, and large coelomocytes mediate lytic reactions against several targets. Destruction of tumor cells in vitro shows that phagocytosis and natural killer cell responses are distinct properties of coelomocytes. A third type, the chlorogogen cell, synthesizes and sheds effector lytic molecules. Among the lytic molecules, three have been identified and sequenced (fetidins, CCF-1, lysenin) and another has been discovered (eiseniapore), while three other molecules, H(1) H(2) H(3), share agglutinating and lysing functions. In contrast to these, Lumbricin I is the only known molecule of the earthworm system that is antimicrobial but non-lytic. Altogether the cellular and humoral components of the earthworm system function to distinguish between self and not self, dispose of internal (cancer?), damaged components and external antigens (microbes). The evolutionary context of the earthworm innate immune system is discussed at the end of this article.

Earthworm leukocytes react with different mammalian antigen-specific monoclonal antibodies

We identified conserved molecules (enzymes, peptides, cytokines) that might play a role in invertebrate innate immunity. We found these molecules by immunoserological and immunohistochemical methods in association with coelomocytes, leukocytes located in the coelomic cavity of the earthworm Eisenia foetida. We detected the enzyme Cu-Zn-superoxide-dismutase (SOD), cytokines (tumor necrosis factor-alpha, TNFalpha; transforming growth factor-alpha, TGFalpha; and alpha peptide hormone, thyreotrope stimulating hormone, TSH) in earthworm coelomocytes with monoclonal antibodies developed originally against human and/or mouse antigens. Three coelomocyte subpopulations were identified according to their form, size and granularity by microscopic and flow cytometric analysis. These cell populations showed different reactivity with antibodies against mammalian cell surface (CD) markers and different intracellular antigens. Two coelomocyte types showed cell surface positivity with anti-Thy-1 (CD90), CD24 and TNF-alpha antibodies. Strong cytoplasmic reaction was shown with anti-TNF-alpha and anti-SOD mAbs and a weaker but unambiguous reaction with thyroid stimulating hormone (TSH) in two cell populations. The third population was negative for all of the monoclonal antibodies. Our flow cytometric results were confirmed by confocal microscopy both on the cell surfaces and intracellularly.

Immunoglobulin and cytokine expression in mixed lymphocyte cultures is reduced by disruption of gap junction intercellular communication

Connexins (Cx), the protein subunits assembled into gap junction intercellular communication channels, are expressed in primary lymphoid organs and by circulating leukocytes. Human tonsil-derived T and B lymphocytes express Cx40 and 43; circulating human T, B, and NK lymphocytes express Cx43 and directly transfer between each other a low molecular dye indicative that functional gap junctions exist. We now identify specific properties in the immune system underwritten by gap junctions. Mixed lymphocytes cultured in the presence of two reagents with independent inhibitory action on gap junction communication, a connexin mimetic peptide and 18-alpha-glycyrrhetinic acid, markedly reduced the secretion of IgM, IgG, and IgA. The secretion of these immunoglobulins by purified B cells was also reduced by the two classes of gap junction inhibitors. Complex temporal inhibitory effects on the expression of mRNA encoding interleukins, especially IL-10, were also observed. The results indicate that intercellular signaling across gap junctions is an important component of the mechanisms underlying metabolic cooperation in the immune system.

Evidence for perforin-like activity associated with earthworm leukocytes

Earthworm (Eisenia fetida) coelomic fluid contains several leukocytes (coelomocytes): basophils, acidophils and neutrophils as well as chloragocytes. Small coelomocytes and coelomocyte lysate are cytotoxic for the tumor cell target K562. The expression of a lytic factor was investigated by immunocytochemistry using light and transmission electron microscopy. A rat-anti-mouse-perforin-mAb labeled mainly small coelomocytes (nearly 20%) as visualized by light microscopy. TEM analysis using immunogold showed a homogenous labeling in the cytoplasm of small coelomocytes. The highest number of immunogold particles was estimated in coelomocytes with many small cytoplasmic granules. Coelomocytes with large lysosomal granules were also labeled but less intensely. No antibody binding was observed for chloragocytes either in light or electron microscopy. This suggests that the perforin-like activity is associated with only one cell type and that chloragocytes are responsible for other lytic activities. MALDI-MS revealed calreticulin usually associated with perforin in mammalian cells that mediate lysis (e.g. NK, CTL). Together, results strongly suggest the presence of putative perforin in earthworms. This in turn supports the hypothesis that perforin is a conserved component important in immune defense during evolution.