Marine Toxins: From Harm to CharmDaniel G. Baden, Ph.D.

Director, Center for Marine ScienceUniversity of North Carolina Wilmington

Cone Shell ToxinsIn Pain Management

Diarrheic Shellfish Poisonsfor Intestinal Water Balance

Inhaled Red Tide BrevetoxinsIn the Treatment of Cystic Fibrosis

Marine toxins disturb:•Nerve conduction•Memory and learning•Pulmonary function•Immune function•Metabolism

Marine PoisonsAs Molecular Tools

Shellfish, Toxins, And Resistance

How can such

Can such exquisite toxicitybe controlled for useful purposes?

Renewable (Cultured) ResourcesFor Ample Starting Materials:

Brevetoxin Example

•Identify environmental episode

•Isolate clonal cultures

•Purify bioactive material(s) from culture

•Establish criteria for purity

•Characterize mechanism of action

•Determine standard and probe sizes

•Package bioactive material

•Continually revise standards and probes

•Develop distribution system

•Bioactive becomes tool for research

•Availability promotes research and development

•Bioactive becomes precursor to drugsBaden et al:

Renewable (Synthetic) ResourcesFor Pain Management:

Cone Shell Toxin Example

Venomous cone shellsToxin purification Peptide sequencing

Synthetic PeptideToxin Production

For Drug DevelopmentBeginning Clinical

Studies in TreatmentOf Chronic PainResearch Showed

Nerve Signal DisruptionOlivera et al:

A Formal Mechanism to Couple Ocean Studies to Human Health:A Paralytic Shellfish Toxin Story

Alexandrium Alexandrium tamarensetamarense

Toxic Shellfish

X

•Humans possess binding domains•Shellfish have modified channels•Changes involve one AA change

Trainer et al:

synthetic PbTx-3--naphthoate

Natural Brevetoxin

Baseline Brevenaltreated

Baseline Brevenaltreated

Effect of B-Naphthoyl-PbTx-3 on Toxin-Induced Constriction

B-Naphthoyl-PbTx-3 (pg/ml)

0.1 1 10 100 1000

% In

hibi

tion

0

20

40

60

80

100

PbTx-2PbTx-3

+

*

*

*

*

*

* ^

Effect of Brevenal on Toxin-Induced Constriction

Brevenal (pg/ml)

1 10 100 1000

% In

hib

itio

n

0

20

40

60

80

100

PbTx-2PbTx-3 +

+

*

*

Time (min)

0 5 10 15 20 25 30 35 40 45

% R

ete

ntio

n o

f N

eb

uliz

ed

T

c 9

9m

-Su

lfur

Co

lloid

40

50

60

70

80

90

100

110

Beta-Naphthoyl-PbTx-3 (n=4)Sterile Water (n=5)Albuterol (n=2)Brevenal (n=2)

Site-Directed Chemical Modification and Activity Measurement: (Turn Harm Into Charm)

•Brevetoxins cause severe respiratory distress•Effects caused at picogram concentrations•Airway restriction increases over 250%

Natural Brevenal

•Both chemicals •counteract all toxin actions•treat symptoms of Cystic Fibrosis•treat mucociliary disorders•administered by nebulizer

•Three patents are pending•for seafood poisoning therapies•for treatment of mucociliary disease•general chemical structures of drugs

Bourdelais et al:

•Renewable sources of material (environmental exploitation is in the past)•Need a formal mechanism to couple ocean studies to human studies (synergy)•Targeted technology to discover new drugs and antidotes (assays)•Mechanisms for standards and “leads” to be distributed (supply is not free)•Site-directed chemical modification and testing (turn harm into charm)

Recommendations

http://www.niehs.nih.gov/oc/news/ocean.htmhttp://www.nsf.gov/news/news_summ.jsp?cntn_id=100371&org=OCE&from=newshttp://www.ogp.noaa.gov/mpe/ohi/centers.htm