ALCOHOL PERTURBS PLACENTAL/HEPATIC FOLATE TRANSPORT

Project: Research project

Description

The long term objective of this grant is improved understanding of
how alcohol perturbs fetal folate nutrition. Data generated in
the course of the Principle Investigators research has included
biochemical characterization of folate binding proteins (FBPs)
isolated from human placenta and milk. Subsequent studies have
identified that membrane-associated FBPs are specific transport
proteins responsible for folate uptake in intact malignant and
normal human cells. It is therefore appropriate to extend such
studies to models (with partial or complete organs) that simulate
the in vivo situation. Such a model is offered in the in vitro
human single placental cotyledon perfusion system with which the
Co-investigator has extensive practical experience. Preliminary
collaborative efforts have successfully demonstrated that this
model can be used to analyze transplacental folate transport, which
alcohol acutely perturbs. The hypothesis that placental folate
receptors (PFRs) are functionally active in transplacental folate
transport will be tested after definition of the kinetics of
transport (placental uptake and fetal folate delivery) with respect
to extracellular folate concentration dependence, as well as
studies that evaluate the influence of folate receptor occupancy
by ligand. Biochemical methods to specifically perturb PFRs at
their folate binding sites both competitively (using various folate
analogues and specific anti-PFR antibodies) and non competitively
(using an N-hydroxysucimimide ester of folate which specifically
and covalently interacts with PFRs) will be carried out. An
additional mechanism, that of passive diffusion of folates across
the placenta at high extracellular folate concentrations (which has
precedence in isolated human cells) will also be investigated after
PFRs are inactivated. Such alcohol acutely increases fetal folate
delivery, studies will be directed at determining if this is due
to an effect on PFR-mediated or passive diffusion mechanisms.
Additional biochemical studies on cultured placental
cytotrophoblasts using biosynthetic methods will determine whether
the origin of soluble FBPs is from membrane associated PFRs.
Finally, the membrane-associated PFRs (hydrophobic FBPs) as well
as the placental protease that cleaves hydrophobic FBPs to soluble
(hydrophilic) FBPs will be isolated and characterized. Such
studies will lay the foundation for further investigation on the
chronic effects of alcohol on ultimate fetal folate delivery on
primates and placentas of pregnant alcoholics.
StatusFinished
Effective start/end date4/1/893/31/94

Funding

  • National Institutes of Health: $282,254.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health

Fingerprint

Folic Acid
Alcohols
Liver
Carrier Proteins
Placenta
Membranes
Research Personnel
Cotyledon
Organized Financing
Human Milk
Alcoholics

ASJC

  • Medicine(all)