Exposure to Mercury Alters Early Activation Events in Fish Leukocytes

MacDougal, Kent C.; Johnson, Matthew D.; Burnett, Karen G.

doi:10.2307/3433124

Cited by 4 publications

(6 citation statements)

References 11 publications

(13 reference statements)

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“…There have been numerous reports describing the effects of mercuric chloride on immune response mechanisms in several cell types [8–12]. Much of this work has been descriptive, lacking a mechanistic interpretation of the molecular events involved.…”

Section: Discussionmentioning

confidence: 99%

“…These studies have variously reported that, with respect to neutrophils, mercuric chloride may inhibit events such as adherence, polarization, chemotaxis, superoxide production, and phagocytosis [8, 9, 12]. Studies using fish leukocytes have also shown that HgCl 2 alters their activation, thus showing that this is not a phenomenon unique to humans [11]. Many of these neutrophil activities have been linked to membrane proteins as a key mediator.…”

Section: Discussionmentioning

confidence: 99%

“…MacDougal et al . [11] and Rossi et al . [4] have described changes in Ca +2 signalling after mercury exposure in various cell types.…”

Section: Discussionmentioning

confidence: 99%

“…showed that when WEHI‐231 B‐cell lymphoma cells were exposed to environmentally relevant levels of HgCl 2 , tyrosine phosphorylation of various intracellular proteins was increased in parallel with disruption of growth control, suggesting a connection between low‐level mercury exposure and disruption of protein tyrosine kinase‐mediated signal transduction in B cells [6,7]. Other experiments have also shown nontoxic levels of mercury to have detrimental effects on leukocytes, inhibiting functions such as chemotaxis, phagocytosis, and superoxide production [8–13]. These leukocyte functions all have in common the fact that they take place downstream from receptor ligation and signalling.…”

Section: Introductionmentioning

confidence: 99%

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Mercury Inhibition of Neutrophil Activity: Evidence of Aberrant Cellular Signalling and Incoherent Cellular Metabolism

et al. 2001

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Exposure to environmental heavy metals has been reported to affect the immune system. Here, we tested the hypothesis that Hg+2, acting through membrane proteins, disrupts metabolic dynamics and downstream cell functions in human neutrophils. We found that HgCl2 inhibited: (1) polarization and (2) immunoglobulin (Ig)G‐mediated phagocytosis of sheep erythrocytes in a dose‐dependent manner from 2.5 to 10 µm. Because these activities have been linked with pro‐inflammatory signalling, we also studied the effects of HgCl2 on intracellular signalling by measuring protein tyrosine phosphorylation. HgCl2 at doses = 1 µm increased tyrosine phosphorylation. We also studied the effect of HgCl2 on neutrophil metabolism by measuring NAD(P)H autofluorescence as an indicator of intracellular NAD(P)H concentration. After HgCl2 treatment, we found that normal sinusoidal NAD(P)H oscillations became incoherent. We recently reported that the NAD(P)H oscillation frequency is affected by cell migration and activation, which can in turn be regulated by integrin‐mediated signalling. Therefore, we examined the effects of HgCl2 on cell surface distribution of membrane proteins. After exposure to environmentally relevant concentrations of HgCl2 we found that CR3, but not other membrane proteins (e.g. uPAR, FcγRIIA and the formyl peptide receptor), became clustered on cell surfaces. We suggest that HgCl2 disrupts integrin signalling/functional pathways in neutrophils.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…MacDougal et al . [11] and Rossi et al . [4] have described changes in Ca +2 signalling after mercury exposure in various cell types.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mercury Inhibition of Neutrophil Activity: Evidence of Aberrant Cellular Signalling and Incoherent Cellular Metabolism

et al. 2001

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“…Blue gourami lymphocytes incubated with mercury showed increased proliferation at low dosages, which was reversed by higher levels (>0.045 mg/L) (Low & Sin, 1998). In the marine fish Sciaenops ocellatus, mercury treatment (≤10 µM) produced a high-dose inhibition and a low-dose activation of leukocytes as determined by Ca-mobilization and tyrosyne phosphorilation of proteins (MacDougal et al, 1996). More recently, in the European sea bass (Dicentracrchus labrax), in vitro treatment with HgCl 2 induced apoptosis in head-kidney macrophages as well as reduced the ROS production and the benefits of macrophage-activating factors (MAF) (Sarmento et al, 2004).…”

Section: Heavy Metalsmentioning

confidence: 98%

Immunotoxicological Effects of Environmental Contaminants in Teleost Fish Reared for Aquaculture

Cuesta¹,

Meseguer²,

Esteban³

2011

Pesticides in the Modern World - Risks and Benefits

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Hg²⁺ affects the intracellular free Ca²⁺ oscillatory pattern and the correlated membrane conductance changes in Mg²⁺‐stimulated oocytes of the prawn Palaemon serratus

Goudeau¹,

Goudeau²

2002

J. Exp. Zool.

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The impact of mercuric ions (Hg(2+)) on prawn oocytes was examined. Prawn oocytes constitute an unusual system in that they are activated at spawning by seawater Mg(2+), which mediates correlated dynamic changes in intracellular free calcium concentration [(Ca(2+))(i)] and membrane conductance associated with the meiosis resumption. Using a voltage clamp technique and intracellular calcium measurements, we observed that treatment with Hg(2+) (5, 10, and 20 microM) resulted in simultaneous impairments of both (Ca(2+))(i) and membrane current responses to external Mg(2+). Treatment with Hg(2+) also resulted in a gradual dose-dependent slow increase in the baseline level of both (Ca(2+))(i) and membrane conductance, independent of stimulation with external Mg(2+). The effect of Hg(2+) on (Ca(2+))(i) and membrane conductance changes resulted from a block of the signal transduction pathway at some point before the InsP(3) receptor channel involved in Ca(2+) release from the endoplasmic reticulum (ER) stocks. The Hg(2+)-dependent gradual increase in both (Ca(2+))(i) and membrane conductance baseline levels may potentially result from a slow permeabilization of the ER membrane, resulting in Ca(2+) leaking into the cytosol. Indeed, this effect could be blocked with the cell permeable Hg(2+) competitor dithiothreitol, which was able to displace Hg(2+) from its intracellular target regardless of whether external Ca(2+) was present or not.

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Exposure to Mercury Alters Early Activation Events in Fish Leukocytes

Cited by 4 publications

References 11 publications

Mercury Inhibition of Neutrophil Activity: Evidence of Aberrant Cellular Signalling and Incoherent Cellular Metabolism

Mercury Inhibition of Neutrophil Activity: Evidence of Aberrant Cellular Signalling and Incoherent Cellular Metabolism

Immunotoxicological Effects of Environmental Contaminants in Teleost Fish Reared for Aquaculture

Hg²⁺ affects the intracellular free Ca²⁺ oscillatory pattern and the correlated membrane conductance changes in Mg²⁺‐stimulated oocytes of the prawn Palaemon serratus

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Exposure to Mercury Alters Early Activation Events in Fish Leukocytes

Cited by 4 publications

References 11 publications

Mercury Inhibition of Neutrophil Activity: Evidence of Aberrant Cellular Signalling and Incoherent Cellular Metabolism

Mercury Inhibition of Neutrophil Activity: Evidence of Aberrant Cellular Signalling and Incoherent Cellular Metabolism

Immunotoxicological Effects of Environmental Contaminants in Teleost Fish Reared for Aquaculture

Hg2+ affects the intracellular free Ca2+ oscillatory pattern and the correlated membrane conductance changes in Mg2+‐stimulated oocytes of the prawn Palaemon serratus

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Hg²⁺ affects the intracellular free Ca²⁺ oscillatory pattern and the correlated membrane conductance changes in Mg²⁺‐stimulated oocytes of the prawn Palaemon serratus