Project description:Microcystins (MCs) are cyclic hepatotoxins produced worldwide by various species of cyanobacteria. Their structure includes two variable amino acids (AAs) and most of the studies focused on the most toxic variant: the microcystin LR (MC-LR). However, more than 80 MC variants have been described to date. Despite ingestion being the major pathway of human exposure, few in vivo studies have demonstrated macroscopic effects on the gastro-intestinal tract, but no data are available on the affected pathways by several variants on intestinal cells. Here, using a non-selective method, we investigated for the first time the effect of MC-RR and MC-LR on the human intestinal cell line Caco-2 and compared their response at the pangenomic scale. The cells were incubated for 4 hrs or 24 hrs with the same range of sub-lethal concentrations of MC-RR or MC-LR. Low effects were observed for both variants after a short-term exposure. On the contrary, dose-dependent modulations of the genes transcription levels were noticed with MC-RR and MC-LR after 24 hrs. Furthermore, the genomic profiles induced by both variants were similar suggesting a common toxicity mechanism but with higher modulation following MC-LR than MC-RR exposure. However, the functional annotation revealed major differences between the variants effects. Indeed, the well-known MC-LR affected mainly two pathways, the oxidative stress response and the cell cycle regulation, which did not elicit significant alteration following MC-RR exposure. This work is the first comparative description of the MC-LR and MC-RR effects on a human intestinal cell model. It allowed us to suggest differences in the mechanism of toxicity for MC-RR and MC-LR. These results illustrate that the toxicity of MC variants remains a key point for risk assessment.
Project description:Microcystins (MCs) are cyclic hepatotoxins produced worldwide by various species of cyanobacteria. Their structure includes two variable amino acids (AAs) and most of the studies focused on the most toxic variant: the microcystin LR (MC-LR). However, more than 80 MC variants have been described to date. Despite ingestion being the major pathway of human exposure, few in vivo studies have demonstrated macroscopic effects on the gastro-intestinal tract, but no data are available on the affected pathways by several variants on intestinal cells. Here, using a non-selective method, we investigated for the first time the effect of MC-RR and MC-LR on the human intestinal cell line Caco-2 and compared their response at the pangenomic scale. The cells were incubated for 4 hrs or 24 hrs with the same range of sub-lethal concentrations of MC-RR or MC-LR. Low effects were observed for both variants after a short-term exposure. On the contrary, dose-dependent modulations of the genes transcription levels were noticed with MC-RR and MC-LR after 24 hrs. Furthermore, the genomic profiles induced by both variants were similar suggesting a common toxicity mechanism but with higher modulation following MC-LR than MC-RR exposure. However, the functional annotation revealed major differences between the variants effects. Indeed, the well-known MC-LR affected mainly two pathways, the oxidative stress response and the cell cycle regulation, which did not elicit significant alteration following MC-RR exposure. This work is the first comparative description of the MC-LR and MC-RR effects on a human intestinal cell model. It allowed us to suggest differences in the mechanism of toxicity for MC-RR and MC-LR. These results illustrate that the toxicity of MC variants remains a key point for risk assessment. Differentiated Caco-2 cells were exposed to microcystins in free FCS culture medium for either 4 or 24 hours. Sub-lethal concentrations of 10, 50 and 100 M-BM-5M of MC-LR or MC-RR were chosen for 4 hours, while 1, 5 and 10 M-BM-5M were selected for 24 hours. For each condition (including the controls), the solvent concentration was fixed to 2% EtOH for MC-LR and 1.5% of 80% MeOH for MC-RR. Four to five culture replicates per condition were done.
Project description:In this study, we used zebrafish embryos as a model system to investigate the toxic effects of MC-RR on early development and try to elucidate the underlying developmental toxicological mechanisms in a global view at posttranscriptional level. Altered expression pattern of miRNAs in embryos treated with MC-RR was detected by miRNA microarray. We examined microRNA expression profiling in paired MC-RR treated and control embroys of zebrafish. There are 4 biological replicates in MC-RR treated group and control group, respectively.
Project description:Microcystin-Leucine Arginine causes cytotoxic effects in Sertoli Cells We used microarrays to analyze up-regulated and down-regulated genes to investigate the molecular mechanism associated with cytotoxic effects in Sertoli cells treated with MC-LR
Project description:Cyanobacteria produce various cyanotoxins, which can cause severe effects to other organisms. Microcystins, one group of such toxins, primarily produced by species of Microcystis, are strong hepatotoxins and inhibit potently protein phosphatases 1 and 2A. Microcystin is the most studied cyanotoxin, however, others are not investigated. Eutrophication of water bodies promotes the occurrence of toxic algal blooms and since a anthropogenic caused increase in eutrophication events can be observed, it is becoming increasingly important to study the consequences and to increase the knowledge on toxins associated with algal blooms. Recently a new cyanobacteria toxin from a Microcystis strain, CP1020, was described. CP1020 belongs to the class of cyanopeptolins and its toxicity was shown to be comparable to that of microcystin (Gademann et al., 2009). It is a strong protease inhibitor inhibiting trypsin in the picomolar range (IC50 = 670 pM) and effects survival of the freshwater crustacean Thamnocephalus platyurus (LC50) 8.8 μM (Gademann et al., 2009). Nothing is known, however, about the toxicity of CP1020 to fish. Furthermore, no information is available on the toxic modes of action, in addition to the proteinase activity. Consequently our study has the aim to elucidate the modes of action of CP1020 on zebrafish eleuthero-embryos. By using a microarray technique, we will analyse alterations of global gene expression by CP1020 at two different concentrations. Thereby, we hope to elucidate the whole array of affected biological pathways to elucidate the mechanisms by which CP1020 affect fish.
Project description:Intrahepatic cholangiocarcinoma (iCCA) has over the last 10 years become the focus of increasing concern largely due to its rising incidence and high mortality rates worldwide. Microcystin-leucine-arginine (MC-LR) have been reported to be carcinogenic but there are no data on the linkage between MC-LR and iCCA. We used microarrays to detail the change of gene expression in iCCA cells(huh28) treated with MC-LR.
Project description:Cyanobacteria produce various cyanotoxins, which can cause severe effects to other organisms. Microcystins, one group of such toxins, primarily produced by species of Microcystis, are strong hepatotoxins and inhibit potently protein phosphatases 1 and 2A. Microcystin is the most studied cyanotoxin, however, others are not investigated. Eutrophication of water bodies promotes the occurrence of toxic algal blooms and since a anthropogenic caused increase in eutrophication events can be observed, it is becoming increasingly important to study the consequences and to increase the knowledge on toxins associated with algal blooms. Recently a new cyanobacteria toxin from a Microcystis strain, CP1020, was described. CP1020 belongs to the class of cyanopeptolins and its toxicity was shown to be comparable to that of microcystin (Gademann et al., 2009). It is a strong protease inhibitor inhibiting trypsin in the picomolar range (IC50 = 670 pM) and effects survival of the freshwater crustacean Thamnocephalus platyurus (LC50) 8.8 M-NM-<M (Gademann et al., 2009). Nothing is known, however, about the toxicity of CP1020 to fish. Furthermore, no information is available on the toxic modes of action, in addition to the proteinase activity. Consequently our study has the aim to elucidate the modes of action of CP1020 on zebrafish eleuthero-embryos. By using a microarray technique, we will analyse alterations of global gene expression by CP1020 at two different concentrations. Thereby, we hope to elucidate the whole array of affected biological pathways to elucidate the mechanisms by which CP1020 affect fish. Gene expression in zebrafish eleuthero-embryos was measured after exposure for 96h to 100 ug/L and 1000 ug/L CP1020 or to the respective controls. A total of 12 arrays (Agilent 4 M-CM-^W 44 K Zebrafish microarray) were used, including four for the solvent control group, four for the 100 M-NM-<g/L and four for the 1000 M-NM-<g/L CP1020 dose group.