Biomarkers of Lead-Induced Toxicity in Channel Catfish and Human Liver Carcinoma (HepG2) Cells - PowerPoint PPT Presentation

Biomarkers of lead induced toxicity in channel catfish and human liver carcinoma hepg2 cells
Download
1 / 15

Biomarkers of Lead-Induced Toxicity in Channel Catfish and Human Liver Carcinoma (HepG2) Cells. Paul B. Tchounwou Environmental Toxicology Research Laboratory, Jackson State University, Jackson, MS, USA Environmental Technology Consortium Washington, D.C. , March 10-11, 2003.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

Biomarkers of Lead-Induced Toxicity in Channel Catfish and Human Liver Carcinoma (HepG2) Cells

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Biomarkers of lead induced toxicity in channel catfish and human liver carcinoma hepg2 cells

Biomarkers of Lead-Induced Toxicity in Channel Catfish and Human Liver Carcinoma (HepG2) Cells

Paul B. Tchounwou

Environmental Toxicology Research Laboratory,

Jackson State University,

Jackson, MS, USA

Environmental Technology Consortium

Washington, D.C. , March 10-11, 2003


Background and rationale

Background and Rationale

  • Lead is a non-essential element that exhibits a high degree of toxicity to humans

  • It is highly toxic to children, and affects virtually every system of the body

  • It can damage a child kidneys, and central nervous system, and cause anemia

  • At very high levels, lead can cause coma, convulsions and death

  • Even low levels of lead are harmful


Background and rationale1

Background and Rationale

  • Levels as low as 10 ug/dL of blood have been associated with:

    • decreased intelligence

    • behavior problems

    • reduced physical stature and growth, and

    • impaired hearing

  • A child is estimated to lose 2 IQ points for each 10 ug/dL increase in blood lead level

    • Most evidence of harmful effects is found in children whose blood lead levels exceed 10 ug/dL


  • Toxicological profile of lead poisoning in children

    Toxicological Profile of Lead Poisoning in Children

    -----------------------------------------------------------------------------------------------------

    Blood Lead Level Adverse Toxicological

    (ug/dL) Effects

    -----------------------------------------------------------------------------------------------------

    10Reduced IQ, hearing, growth, behavior problems

    20Impaired nerve function

    30Reduced Vitamin D metabolism

    42Damage to blood forming system

    55Severe stomach cramps

    70Severe anemia

    80Kidney damage

    90Severe brain damage

    130Death

    -----------------------------------------------------------------------------------------------------


    Background and rationale2

    Background and Rationale

    • Most studies with lead have focused on its effects on organ systems such as the nervous system, the red blood cells, and the kidneys which are considered the primary targets of toxicity.

    • However, little is known about its adverse effects on the liver and other tissues. The literature is also scarce regarding the molecular mechanisms of lead-induced toxicity in mammalian systems.


    Why channel catfish

    Why Channel Catfish ?

    • Aquatic organisms (fish/crawfish) are important sources of food, and income for several residents

    • Mississippi is No. 1 producer of catfish in the nation

    • Contaminated fish may constitute a significant route of human exposure to lead thru the food chain


    Research objectives and approach

    Research Objectives and Approach

    • To assess the acute and chronic toxicities of lead to channel catfish (ictalurus punctatus)

      • Static renewal bioassays with fish exposed to lead nitrate (acute)

      • Flow-through system bioassays with fish exposed to lead nitrate (chronic)

  • To determine the cytotoxicity of lead

    • MTT assay for cell viability with transformed human hepatocytes exposed to lead nitrate


  • Research objectives and approach1

    Research Objectives and Approach

    • To predict the molecular mechanisms of lead-induced toxicity

      • Gene Profile (CAT-Tox) to assess the transcriptional activation of stress genes

      • Microarray analysis for large scale gene expression

  • To identify the potential biomarkers of exposure, sensitivity and effect associated with lead exposure

    • Western Blot and densitometric analyses

    • Histopathological examinations


  • Preliminary studies

    Constants:

    Volume of Water (1.2L)

    Renewal of Medium (every 24hrs)

    Time of exposure (96hrs)

    Number fish (4)

    No Feeding or Aeration

    Water Quality:

    pH

    Dissolved oxygen

    Temperature

    Conductivity

    Total dissolved solids

    Preliminary Studies


    Water quality

    Water Quality


    Acute toxicity of lead to channel catfish 48 hrs exposure

    Acute Toxicity of Lead to Channel Catfish – 48 hrs Exposure


    Preliminary findings

    Preliminary Findings

    • The concentration of lead has a direct effect on the mortality rate of channel catfish.

    • The toxicity of lead is dose- and time-dependent.

    • Lead is acutely toxic to channel catfish


    Cytotoxicity of lead nitrate to hepg 2 cells 48 hrs exposure

    Cytotoxicity of Lead Nitrate to HepG2 Cells – 48 hrs Exposure


    Stress gene promoter response element cat fusion constructs

    Stress Gene Promoter/Response Element-CAT Fusion Constructs

    -----------------------------------------------------------------------------------------------------------------

    PromoterBiologic Function

    -----------------------------------------------------------------------------------------------------------------

    CYP1A1Cytochrome-P450 1A1Phase I biotransformation enzyme

    GST YaGlutathion-s-transferase Phase II biotransformation enzyme

    XREXenobiotic Resp. Elt.Binding site for Ah-receptor

    CREcAMP Response Elt.Binding site for the CREB protein

    RARERetinoic Acid REBinding site for RA

    HMTIIAMetallothioneinSequestration of heavy metals

    HSP70Heat Shock Protein Cytoplasmic protein chaperone

    GRP78Glucose-Regulated PER protein chaperone

    GADD45/153 GA & DNA Damage PCell cycle regulation

    FOSc-fosMember of AP-1 TF complex

    NFkBRENuclear FactorBinding site to the NFkB TF

    p53RETumor Suppressor PBinding site for the p53 TF

    -----------------------------------------------------------------------------------------------------------------


    Deliverables

    Deliverables

    • Education and workforce development

      • Strengthen curriculum in the areas of environmental toxicology and risk assessment

      • Educate and train under-represented students in the areas of environmental toxicology and risk assessment

  • Contribution to science / Research

    • Review and update the toxicological profile of lead

    • Identify and elucidate the mechanisms of lead-induced toxicity

  • Scientific publications ( 3 in 3 years)

  • Scientific presentations ( 6 in 3 years)

  • Faculty development in the area of environmental toxicology and risk assessment

    • Seminars / workshops / conferences


  • Login