Anti-secretory Action of Estrogen in the Intestine

Brian Harvey

Department of Molecular Medicine

Royal College of Surgeons in Ireland

The Physiological Society Membrane and Epithelial Transport Symposium

Newcastle-upon-Tyne 2009

RCSI Molecular Medicine

Estrogen rapid responses

Rodrigo Alzamora

Fiona O’Mahony

Warren Thomas

Estrogen and Fluid Retention

O’Mahony & Harvey J Physiol 2009

X

Anti-secretory action of Estrogen

O’Mahony & Harvey Mol Endo 2008Condliffe, Doolan & Harvey J Physiol 2001

O’Mahony & Harvey JBC 2007 O’Mahony et al. Mol Endo 2009

PKC

Estrogen Inhibits Secretion in Colonic Epithelia

Condliffe, Doolan, Harvey J Physiol, 2001.

E2

control

E21nM

Estrogen Inhibits Secretion via PKC

E2

E2 -PKC

Rottlerin

Condliffe, Doolan, Harvey J Physiol 2001.

Estrogen Rapidly Inhibits KCNQ1

Currents in Single Isolated Crypts

1nM

O’Mahony & Harvey J Biol Chem, 2007.

Estrogen Phosphorylation of the KCNQ1 Channel

is PKC and PKA dependent

-PKC -PKA

E2E2

E2

O’Mahony & Harvey J Biol Chem, 2007.

Summary

Estrogen causes a rapid and sustained inhibition of

both Ca2+ and cAMP driven chloride ion secretion

via PKC - PKA phosphorylation of KCNQ1 channels

causing closure and retrieval of the channel

Estrogen inhibits basal secretion and secretion activated

by cholera toxin and heat-stable enterotoxin

Is the estrogen receptor involved?

Is the response female-specific?

Questions

A plasmamembrane-associated 66kDa mER

transduces E2 activation of PKC

O’Mahony et al. Mol Endo 2009.

Anti-secretory E2 response is female

sex-specific and estrus cycle dependent

Cl- secretion

rate

O’Mahony et al. Mol Endo 2009.

% Isc

Sex differences in ion transporter expression

O’Mahony and Harvey. Steroids, 2008.

Na/K pumpCFTR

NKCC1 KCNE3

Male Female Male Female

Female sex-specific activation of PKC by E2

Female

Male

O’Mahony et al. Mol Endo 2009.

PKC E2PKCAI

Endocytosis

Intracellular

pool

Exocytosis

Cl-

K+

Apical

P

MAPK

PKCAI

CREB

Short term anti-

secretory effect

Transcriptional

priming

Long term anti-

secretory effect

Basolateral

Rapid and Genomic Ion transporter Responses to E2

PKC

NKCC1

KCNQ1

Na/K

ATPase

CFTR

2Cl-

Na+

K+

Na+

K+

mER

O’Mahony & Harvey. J Physiol 2009.

Estrogen regulates Cl- secretion

via PKC inhibition of KCNQ1 channels

The anti-secretory response is female sex-specific

and estrus cycle dependent

Estrogen regulates the expression of protein kinases

and ion transporters to effect sustained inhibition of secretion

A membrane-bound 66KDa mER mediates

the rapid kinase responses to estrogen and genomic priming

of the anti-secretory response

Summary

mER

mERrole in ion transport and cell proliferation

KCNQ1

K+Ion transport

response

Cell proliferation

response

mER

O’Mahony & Harvey. Steroids 2008.

MAPK Expression is Gender Regulated

Male Female Male Female

O’Mahony et al. Mol Endo 2009.

CREB is Phosphorylated in the nucleus in Response to E2

And is MAPK and PKA Dependent

O’Mahony et al. Mol Endo 2009.

Rapid mER-estrogen regulated transcriptional responses

O’Mahony et al. Mol Endo 2009.

Conclusions

• Estrogen inhibits epithelial ion and fluid secretion in females only

• The anti-secretory response to estrogen has both beneficial and pathological effects in intestine and lung, respectively

• The KCNQ1:KCNE3 channel is differentially regulated by estrogen in females

• The mER receptor transduces rapid anti-secretory responses to estrogen and primes the genomic phase of expression of protein kinases, ion channels and receptors,

and cell proliferation

MAPKMAPK

CREBCREB

PKC mRNA mRNA

PK

A

PKC

mER

The molecular mechanisms for estrogen anti-secretory responses

are similar in colon and bronchus

Dehydration of mucus layer

Estrogen in CF, asthma ??

Estrogen and KCNQ1 channels

in CF and Asthma?

Respiratory function in Asthma and Cystic Fibrosis

is exacerbated in females at puberty - role for E2?

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Hours

AS

L H

igh

mm

CuFi_1

NHBE

1H 4H 12H 24H

CuFi_1

ASL stabilized

A

CuFi control

CuFi + E2

Estrogen reduces ASL in CF bronchus

Summary

The estrous cycle differences in the anti-secretory

response to estrogen may be important for fluid retention

and volume expansion required for implantation of the

embryo

The anti-secretory effects of estrogen are observed in

other epithelia such as endometrium, sweat gland, renal

CCD and bronchus.

Estrogen modulation of KCNQ1 channel activity has

important physiological implications for female-specific

responses in secretory diarrhoea, Cystic Fibrosis,

Asthma ….