Microcystin‐LR modulates selected immune parameters and induces necrosis/apoptosis of carp leucocytes

Abstract

Microcystins (MCs) are potent hepatotoxins acting by the inhibition of protein phosphatase 1 and 2A, and may promote liver tumors. Moreover, studies also suggest they are nephrotoxic. The aim of the present study was to assess possible in vitro effects of microcystin-LR (which contains the amino acids leucine and arginine, the most widely studied and distributed variant of all microcystins) on the selected immune functions of the cells isolated from the head kidney of carp. In the experiments, pure microcystin-LR (MC-LR), was used at concentrations of 0.01, 0.1, 0.5, and 1 microg/ml RPMI-1640 medium. Leucocytes (lymphocytes and phagocytes) were isolated by centrifugation on a density gradient. Lymphocyte proliferation, intracellular production of reactive oxygen species by phagocytes, and the presence of apoptotic and/or necrotic cells were assessed. The respiratory burst activity of phagocytic cells was increased at the lowest toxin concentration used in the study, but it was decreased at higher concentrations. Using a sensitive luminescent immunoassay, MC-LR was observed to have no influence on the T-cell proliferation but decreased the proliferation of B lymphocytes. Moreover, it was noted that MC-LR induced necrosis to a higher degree than apoptosis in fish leucocytes. The results of the present study suggest the modulatory potency of microcystin-LR on fish leucocytes.

Experimental immunology Cytotoxic and immunotoxic effects of the mixture containing cyanotoxins on carp cells following in vitro exposure

“…4). Comparing the results of the present study with the results of previous studies, we can conclude that the lymphocyte proliferation and phagocytosis in cells incubated with the toxin mixture were more significantly decreased than those in MC-LR or ATX-a treatment alone [10,11,13,15]. The results suggest the synergistic effect of these various types of cyanotoxins.…”

“…Rogers et al [16] concluded that the synergistic effect of MC-LR and ATX-a was due to the different routes toxin uptake. The results of our previous in vitro and in vivo investigations also showed that the extract containing MCs or ATX-a Anna Rymuszka et al induced greater suppressive effects on essential functions of immune cells (ROS production, lymphocyte proliferation and cytokine production) than the pure toxins alone [10][11][12][13]15]. Probably, the extract contained other unknown toxic metabolites produced by cyanobacteria which were responsible for the observed toxicity [17].…”

Involvement of oxidative stress and cytoskeletal disruption in microcystin-induced apoptosis in CIK cells

“…Furthermore, we regarded this dualistic response to different doses of MCs as hormesis, which is a biphasic dose-response phenomenon and characterized by low-dose stimulation and highdose inhibition (Calabrese, 2008). Hormesis of MCs has also been reported in common carp pronephros phagocytes (Rymuszka et al, 2010), crucian carp , human amniotic epithelial (FL) cells (Liang et al, 2011), HeLa cells (Chen et al, 2014), and even plants, rape and cabbage (Liu et al, 2008).…”

Pro- and anti-inflammatory cytokine expression in carp blood and head kidney leukocytes exposed to cyanotoxin stress – An in vitro study

“…Examination of the levels of expression of selected proinflammatory (IL-1 b, TNF-a) and anti-inflammatory (IL-10, TGFb) cytokines released from carp leukocytes, can largely help to explain changes in the functioning of phagocytes and lymphocytes observed in our previous studies [14,21], in response to in vitro exposure to selected cyanotoxins: MC-LR and Antx-a.…”