Estrogens
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Estrogens. You can’t live without ‘em: Reproductive failure Bone loss Vasomotor disturbances (hot flashes) Some cardiovascular system vulnerabilities Some cognitive declines, mood disorders Skin changes You can’t live with ‘em: Cancer (breast, uterus, colon, pituitary) Blood clots

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Estrogens

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Estrogens

Estrogens

You can’t live without ‘em:

Reproductive failure

Bone loss

Vasomotor disturbances (hot flashes)

Some cardiovascular system vulnerabilities

Some cognitive declines, mood disorders

Skin changes

You can’t live with ‘em:

Cancer (breast, uterus, colon, pituitary)

Blood clots

Nausea or eating disorders

If you have the wrong ones (xenoestrogens) you’re in big trouble: endocrine disruption of many types


Xenoestrogens xes are threats to both sexes physiologic e levels vs sex age cycles pregnancy

Xenoestrogens (XEs) are threats to both sexesPhysiologic E levels vs. sex, age, cycles, & pregnancy


Watson stke dec 1999

Watson, STKE Dec 1999

How do estrogens and xenoestrogens signal in the cell?

ER

ER

GPR30/

(ERα36)

Both:

From the nucleus (classical genomic mechanism)

From the membrane

(novel, nonclassical nongenomic mechanism)


Confocal views of e 2 peroxidase binding in gh3 b6 f10 pituitary tumor cells

Confocal views of E2-peroxidase binding in GH3/B6/F10 pituitary tumor cells

Visualizing Membrane Estrogen Receptors (Binding)

Nataliya

Bulayeva


Estrogens

Detection of PROTEIN•PROTEIN epitope interactions – the proximity ligation assay (PLA)

Either two ERα Abs or Abs for two differenent proteins

mAb (AB-N09)

R Ab -

mAb +

mAb

R Ab


Estrogens

Slice 3D

epitope proximity for ER

Two epitopes from within ERα

Guangzhen Hu


Er partnering with either g i or caveolin

Slice

3D

ERα partnering with either Gαi or Caveolin

Guangzhen Hu


Estrogens

Estrogens (either physiologic or environmental) cause rapid disappearance of mERα Ab recognition (H151 hinge region epitope) while other epitope signals are not affected – rapid conformational change.

GH3/B6/F10 pituitary tumor cells

3 min

DES

(Similar for:

E2, dieldrin, endosulfan, nonylphenol)

15 min

veh

Such responses are both rapid and potent

Celeste Campbell


Estrogens

Ever since then we have been examining mechanisms of rapid E and XE actions, related to - functional outcomes – looking at ways XEs can disrupt normal function.


Estrogens

So many estrogens… so little time!

We picked these 16 originally to compare because of interests our interests in:

■ life-stage prevalence of physiological estrogens

■ xenoestrogen toxicities and disease associations

■ structural features/groupings

■ therapeutic uses

All small molecules ~270-400 MW

… and we are adding more compounds all the time to enhance our stucture-activity analyses


Estrogens

Some typical results using these assays: have taught us important concepts about how these compounds act via nongenomic mechanisms


Estrogens

We see non-monotonicdose-responsesfor E2-induced PRL release from GH3/B6/F10 pituitary cells at 6 min (also true for other estrogens)

Prolactin (PRL) secretion

PRL secretion

Andrea Norfleet/Jennifer Jeng


Xenoestrogens also cause prl release in a nonmonotonic pattern

Xenoestrogens also cause PRL release in a nonmonotonic pattern

Bisphenol A

*

*

PRL/CV (% of control)

*

10-12 10-11 10-10 10-9 10-8

Big news for the toxicology world -- Nonmonotonic responses make it impossible to extrapolate back from a high dose to see what the lowest effective dose would be.

Ann Wozniak


Estrogens

ERα is necessary for many of these responses

Cells selected for very low mERα levels (D9 subclone) ….can’t elicit the PRL response to estrogens.

D9 Cell Dose Dependent PRL Release

at 3 Minutes

D9 Cell Time Dependent PRL Release

at 10-8M E2

PRL/CV (% of Control)

10-12M

10-11M

10-10M

10-9M

10-8M

E2 Concentration (M)

Time (minutes)

Ann Wozniak


Estrogens

To efficiently identify specific receptors involved, we have also used

--siRNA knockdowns of NRs

ER primarily responsible, , and GPR30 sometimes modulatory

--receptor-selective agonists

--receptor-selective antagonists

To prove action from the membrane we have used:

--various impeded ligands (E2-BSA, E2-peroxidase, E2-dendrimers)

--ERα Ab triggering of responses


What signaling mechanisms may be provoked by xenoes acting on mers

What signaling mechanisms may be provoked by xenoEs acting on mERs

Ca++

mitogen-activated protein kinases (MAPKs)

cAMP and PKA

G protein activations

other kinases/phosphatases

caspases

downstream transcription factor post-translational modifications

and how they relate to functional endpoints


Estrogens

Cell signaling is complicated - not just a linear signaling cascade. Many things must be coordinated. It is a web.


Signaling is like a rube goldberg machine http blueballfixed ytmnd com

Signaling is like a Rube Goldberg Machine http://blueballfixed.ytmnd.com/

created by the Web site Something Awful


Estrogens

 - non-nuclear feeder signaling streams we have tested & found to be involved in E-induced downstream ERK signaling

Mitogen-activated protein kinases (MAPKs) like ERK:

Are signal integrators. …..many signaling pathways funnel into the ERK “integrator”.

Are associated with major cellular destinies, like cell proliferation


Estrogens

Signaling starting at the membrane funnels into the downstream kinases ……and then fans out again to coordinate major complex downstream functions.The MAP kinases are the integrators that separate these two phases


Estrogens

Proliferation

cell cycle

receptors

DNA and protein

synthesis for replication

MAPKs

ERKs

JNKs

p38

2nd messengers and signaling enzymes (kinases, and phosphatases, lipases, NT-cyclases) and scaffolds

new proteins

caspase cascades

Differentiation

Death

Migration

Secretion


Estrogens

One of our most useful techniques is a fixed-cell 96-well plate immunoassay which: --is optimized for each cell type, epitope-Ab, and cell compartments (based on permiabilization); makes use of the many Abs now available to the activated (usu. p’ated) form of proteins-- is relatively high throughput allowing us to compare multiple xenoestrogens at a wide range of concentrations acting on multiple antigens-- allows us to do physiologic Es + XEs in incremental mixtures, the real-life scenarios of XE toxic exposures


Estrogens

Responses oscillate with time; XEs cause different phasing than E2

Nonylphenol

DDE

E2

Coumestrol

ERK activation - % of control)

DES

Dieldrin

Endosulfan

E2-Peroxidase

time, min

96-well plate immunoassays for phospho-ERK ligands all at 1nM

Nataliya Bulayeva


Estrogens

Responses are often non-monotonic: U-, V-, or M-shaped dose-responses

ERK activation

Concentration

Nataliya Bulayeva


Why do mapk responses oscillate oscillate with time and concentration

Why do MAPK responses oscillate oscillate with time and concentration.


The sum of pathways a b is an oscillating curve over time or concentration

The sum of pathways A & B is an oscillating curve over time or concentration


Estrogens

Some responses are very rapid – seconds

Here is a new example of one of the most rapid -- Gi activation(charged with GTP and assayable with an Ab to the charged form).

Because it is so proximal to receptor-binding it is much more rapid (peaks at 15 seconds) than downstream signal integrator responses like for MAPKs (several minutes). Again see differences between E2 and XEs

Guangzhen Hu


Estrogens

Proliferation function downstream of MAPKs are affected by XEs

Both physiologic estrogens and xenoestrogens cause pituitary cells to proliferate (just as pituitaries and their tumors grow in response to estrogens)…

Jennifer Jeng


Estrogens

Mechanisms that affect cell number – apoptosis – are elicited by XEs

Rene Vinas


Examples elk and atf2 with some differences in response pattern

…Es and XEs (in this case phytoEs) can also rapidly activate (phosphorylate) transcription factors downstream of ERKs

Examples: Elk and ATF2, with some differences in response pattern

Jennifer Jeng


Estrogens

To summarize the 1st part…endocrine disruption by xenoestrogens includes:

 altered timing (phasing)

 altered dose-response patterns and levels

 imperfect mimicry or inhibition of multiple estrogenic actions activated via the nongenomic pathways

Can a structure/chemical characteristic of an estrogen predict its activity in a nongenomic response?


Estrogens

Here again are the ones we have studied

They can all be described by their physical characteristic of lipophilicity – the partition coefficient between octanol and water

Short chain alkylphenols are less lipohillic than long chain ones


Estrogens

13 estrogens – their activities in various functional and signaling responses compared to their hydrophobicity

Best correlations are for structures that vary in simple ways (side-chain length)

 E2 1 nM

 E1 1 nM

 E3 1nM

Cou 10 nM

 Dai 100 nM

 Gen 100 nM

 Res 100 nM

 EP 1 nM

 PP 1 nM

OP 1 nM

 NP 1 nM

 BPA

DES

The most complicated - both genomic and

nongenomic pathway

control

(Chlorinated compounds were left out as they significantly reduced the correlations)

Chemists can use such information to design less estrogenic versions of these compounds

Jennifer Jeng

Mikhail Kochukov


But in real life these estrogens are rarely present by themselves

But in real life these estrogens are rarely present by themselves

You have physiologic estrogens on board already – and then you get exposed to xenoestrogens on top of that.

Do xenoestrogens interfere with physiologic estrogens? Do they disturb the normal signaling patterns? How?

In different ways - examples for ERK signaling follow that demonstrate some principles of estrogenic endocrine disruption.


Estrogens

Temporal phasing of response….XenoEs can delay the response after causing an initial dephosphorylation

pERK

Time in Minutes

Jennifer Jeng


Estrogens

XEs can enhance an estrogenic response at concentrations where it is less effective by itself; inhibit at higher concentrations – this is the most typical effect of combinations

(physiologic estrogens all at 1 nM for these studies; 5 min responses)

Have assessed for 3 physiologic estrogens challenged by 5 different XEs

Jennifer Jeng


Estrogens

Extreme Disruption by Multiple XEs - can completely wipe out a physicologic E response – we have seen this now with multiple combinations of XEs.

Rene´ Viñas


Any of these alterations disrupts the normal pattern or extent of physiologic estrogen signaling

Any of these alterations “disrupts” the normal pattern or extent of physiologic estrogen signaling.


Estrogens

In summary we have learned that Es/XEs acting via nongenomic pathways:

► signal more potently via the membrane versions of estrogen receptors

►activate multiple signaling pathways

► responses often oscillate with time and are non-monotonic (U- V- or even M-shaped dose-responses and XEs alter this to disrupt signaling – a difficult target for regulation

► mediated primarily via ER (depending on tissue); modulated by other ER subtypes

► XEselicit tissue-specific disfunctions (secretion, differentiation, cell proliferation, enzymatic cascades, components of inflammatory responses, behavior, ROS)in different nontransfected cell types: pituitary, breast, prostate, neuronal, cells of the immune system……

► have particular developmental window / stage-specific vulnerabilities to XEs

► chemical structures of Es/XEs can predict strength/potency of nongenomic responses

► XE mixtures (which is what we are exposed to) dramatically disrupt physiologic E responses


Estrogens

How we would like to use our newly determined principles learned via high throughput signaling assays: Green Chemistry Design

nongenomic cell signaling - later assigned to a NR

remediation of existing contamin-ants

animal develop-ment - later assigned to a NR

NR binding and NR-based genomic response

in silico chemical- receptor docking

REDESIGN

We are currently collaborating with labs who view endocrine disruption at different (increasingly more complicated) levels.

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A cknowledgements

Acknowledgements

Acknowledgements

Watson lab – over the years working on nongenomic E signaling projects

Todd Pappas

Celeste Campbell (Finnerty)

Andrea Norfleet

Adrian Jakubas

Bridget Hawkins

Gaga Zivadinovic

Nataliya Bulayeva

Teresa Reed

Leanne Lash

Ann Wozniak

Rebecca Alyea

Yow-Jiun Jennifer Jeng

Mikhail Kochukov

Stephanie Laurence

Anannya Banga

Luke Koong

June Guptarak

Guangzhen Hu

Rene Vinas

Manish Saraf

Collaborators: Bahiru Gametchu, Mary Thomas, Kathryn Cunningham, Randy Goldblum & Terumi Midoro-Horiuti

Green Chemistry Collaborators: Ruben Abyuan & Fiona McRobb, Bruce Blumberg, Susan Jobling, Terry Collins, John Warner, Pete Myers & Karen O’Brien

Funding

NIEHS (R01s and training grant)

NIDA (P20 Center and training grant)

Am. Inst. for Cancer Research

UTMB Center for Addiction Research

Sealy Center for Environ. Health & Medicine

Passport Fndn. Innovator Award


Estrogens

Immuno-assay for quantitation of membrane vs. intracellular proteins, their trafficking, and their activation state

outside

inside

Fix cells: various methods to match epitope and cell type

-- unpermeabilized measures membrane proteins

-- permeabilized (usu. with detergent) measures intracellular proteins

(We have used it for various ERs, DAT, pMAPKs, and p-transcription factors, and GTP-G proteins in many different cell types)

Incubate with 1°Ab; biotinylated 2° Ab; avidin-conjugated alk. phos.

Incubate with pNpp →pNpat 37° in dark, & read at 405 nm Ag quantitation

Wash off reagents

Stain with 0.1% crystal violet, wash, extract, read at 562 nM cell number (normalization for each well)


Estrogens

molecules- receptors -- cell signaling - organisms- remediation

genomics nongenomics

In silico – Ruben Abyuan and Fiona …..

Receptor binding and genomic activation – Bruce Blumberg

Nongenomic cell-type specific signaling – Cheryl Watson

Developing organisms – Susan Jobling

Remediation – Terry Collins, John Warner

Cementing it all together – Pete Myers and Karen O’Brien


Estrogens

In silico cell-free cell dependent development chemical capture

of amphib & fishes and degradation


Do taml activators activate erk no

Do TAML activators activate ERK – NO!!!!!


Estrogens

www.secondlife.com

CW searching for receptors, wherever they are in the cell

Genome Island, Genome (139,145, 37)


Estrogens

Crucial difference between our studies and past studies on xenoestrogens:

●we look at rapidnongenomic effects

●we use very low (fMnM) concentrations (very relevant to those found commonly in the environment) within very wide concentration ranges ….and sensitive, quantitative cellular response assay systems

●we use non-transfected cell systems to avoid overexpression and heteroexpression artifacts


The assays we plan to do in gh3 b6 f10 pituitary cells for the green chem center project

The assays we plan to do in GH3/B6/F10 pituitary cells for the Green Chem Center Project

  • Signaling assays

    --G protein activation (proximal signaling)

    --ERK (+JNK & p38) kinase activations (downstream integrated signaling)

  • Function assays

    --PRL release (nongenomic functional endpoint)

    --Cell proliferation (complex functional endpoint)


If the money got bigger i could add

If the money got bigger I could add:

  • Other cell types in which we have already monitored nongenomic signaling effects (breast cancer, prostate cancer, neuronal, immune system)

  • Other myriad signaling pathways (IPs, ions, other kinases, activation of transcription factors)

  • Other functional endpoints


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