Gottlieb Lab Research Summary
Mechanisms
of Cardioprotection
Our research is focused on developing
ways to protect the heart after ischemia and reperfusion.
We use a range of approaches including
cell biology, organ physiology, biochemistry and
molecular biology to understand the intracellular
processes that determine whether the cardiac cells
will survive and repair, or undergo programmed
cell death through apoptosis or necrosis. We use the heart as our primary model organ
but conduct many studies in cell lines or primary
cell culture, using fluorescence microscopy to
monitor intracellular processes in real-time in
living cells.
We have a number of NIH-funded projects
underway.
Rescue and Role of Complex
I in Myocardial Ischemic Injury:
Members of the Bcl-2 family function at
the mitochondrial outer membrane to regulate programmed
cell death, or apoptosis.
Bax and Bak are multi-domain pro-apoptotic
members of the family, but their activity is directly
or indirectly regulated by proteins of the BH3-only
subfamily (Bcl-2 relatives that only share homology
in domain 3). We are interested in Bid, a BH3-only protein
that is proteolytically activated during ischemia/reperfusion
and targets the mitochondria to initiate apoptosis.
Mitochondria can promote necrotic cell
death through a second pathway involving a mysterious
entity known as the Mitochondrial Permeability
Transition Pore, which includes cyclophilin D
and other components that are the subject of intense
investigation.
We hypothesize that the electron
transfer Complex I may be a part of the
pore and may be regulated by Complex I. We have developed a cell-permeable therapeutic
protein that can protect the heart against ischemia/reperfusion
injury, and we plan to test its usefulness in
additional model systems.
Subcellular Regulation of
Autophagy: Autophagy is a cellular housekeeping process
in which damaged organelles or insoluble protein
aggregates are sequestered in a double membrane
and routed to the lysosome for degradation. We hypothesize that Bcl-2 family members regulate
this process as well as apoptosis, and are interested
in understanding how mitochondria may be selectively
targeted for removal by autophagy. We are also interested in understanding mitochondrial
fission and fusion as a means to maintain high-quality
mitochondria in the heart.
The role of autophagy in cardioprotection
is an exciting new area of interest that is expanding
rapidly. In
collaboration with Drs. Tom Cole (Chemistry) and
Kim Finley (BioScience Center),
we are developing novel tools to study and modulate
the process of autophagy.
Mitochondria and Stem Cells
in Anthracycline-Induced Heart Failure:
Anthracyclines are anti-cancer drugs that
are used widely to treat childhood malignancies. However, a number of cancer survivors develop
heart failure 10-20 years later.
Because cardiomyocytes persist in the heart
for decades, it has been assumed that cells sustain
direct injury that results in eventual cytotoxicity. However, in collaboration with Dr. Asa Gustafsson
(BioScience
Center),
we now have evidence that anthracyclines cause
early senescence of cardiac stem cells that are
needed for life-long growth and repair, resulting
in a limited ability of the heart to respond to
physiologic stress.
We are exploring the possibility of stem
cell therapy to prevent this tragic complication
of chemotherapy.
Development of Small-Molecular
Cardioprotective Agents for Treatment of Reperfusion
Injury: We
are investigating novel compounds that protect
the heart from ischemia/reperfusion injury, even
when given after ischemia, at the time of reperfusion.
The mechanism of protection, optimization
of lead compounds, and preclinical studies are
underway in collaboration with Dr. Paul Wentworth
(Chemistry, The Scripps Research Institute), Dr.
Mark Yeager (Cell Biology, The Scripps Research
Institute), and Dr. Robert Mentzer, Jr. (Cardiothoracic
Surgery, Wayne State University School of Medicine).
Microbial
Basis of Cardiovascular Disease
The focus of the BioScience
Center
is understanding role of infection and inflammation
in the development of heart disease. A number of early-stage collaborative projects
are underway.
Role of Autophagy in Innate
Immunity: We are interested in understanding how inflammatory
mediators and innate immunity regulate autophagy. For instance, the bacterial cell wall lipid,
lipolysaccharide (LPS) triggers production of Tumor Necrosis
Factor alpha (TNF-a)
which in turn triggers autophagy.
Is autophagy part of the injury process
or a repair response? How do bacteria (Porphyromonas gingivalis), viruses (Coxsackievirus), and protozoans
(Trypanosoma cruzi) modify
the cellular autophagy machinery to escape destruction
once they have entered the cell?
Can we modify the infection or disease
process by modulating autophagy?
Role of Periodontal Pathogens
in the Development of Atherosclerosis:
In collaboration with investigators in
Biology, Computational Science, and the Graduate
School of Public Health, we are conducting a community-based
investigation to determine if treating gum disease
(periodontal disease) can prevent atherosclerosis.
We are using a metagenomics approach to
define the oral microbiome
in health and disease.
This collaboration involves Drs. Scott
Kelley, John Mokili, Forest Rohwer (Biology),
Suzanne Lindsey (Graduate School of Public Health),
and Anthony Demaria (Chief of Cardiology, UCSD).
Coxsackieviral
Infection of Cardiac Stem Cells:
An extension of the study of anthracycline
cardiotoxicity is underway to test the possibility
that viral infections in childhood might cause
early senescence of cardiac stem cells that are
needed for life-long growth and repair, resulting
in a limited ability of the heart to respond to
physiologic stress and eventual heart failure.
This work is being conducted in collaboration
with Drs. Ralph Feuer (Biology) and Dr. Asa Gustafsson
(BioScience
Center).
Recent
Publications
1.
Iwai-Kanai E, Yuan
H, Huang C, Sayen MR, Perry-Garza CN, Kim L, Gottlieb
RA. A Method to Measure Cardiac Autophagic Flux
in vivo. Autophagy
4:322-9, 2008.
2.
Jin JK, Whittaker
R, Glassy MS, Barlow SM, Gottlieb RA, Glembotski
CG. Localization of phosphorylated {alpha}B-crystallin to heart mitochondria during ischemia-reperfusion.
Am J Physiol Heart
Circ Physiol. 294:H337-344,
2008.
3.
Klionsky DJ, Abeliovich H, Agostinis P, et al.
Guidelines for the use and interpretation of assays
for monitoring autophagy in higher eukaryotes.
Autophagy.
4:151-175, 2008.
4.
Tsukada YT, Sanna MG, Rosen H, Gottlieb RA. S1P1-Selective Agonist SEW2871 Exacerbates Reperfusion
Arrhythmias. J Cardiovasc Pharmacol. 50:660-669,
2007.
5.
Benjamin IJ, Guo Y, Srinivasan S, Boudina S, Taylor R, Rajasekaran
NS, Gottlieb RA, Wawrousek
E, Abel ED, Bolli R. CRYAB and HSPB2 deficiency alters cardiac metabolism
and paradoxically confers protection against myocardial
ischemia in aging mice.
Am J Physiol Heart Circ Physiol. 293:H3201-9, 2007.
6.
Brady NR, Hamacher-Brady
A, Yuan H, Gottlieb RA.
The autophagic response to nutrient deprivation
in the HL-1 cardiac myocyte is modulated by Bcl-2
and sarco/endoplasmic
reticulum calcium stores.
FEBS J. 274:3184-97, 2007.
7.
Hamacher-Brady A, Brady NR, Logue SE, Sayen MR, Jinno
M, Kirshenbaum LA, Gottlieb RA, and Gustafsson
AB. Response to Myocardial Ischemia/Reperfusion
Injury Involves Bnip3 and Autophagy.
Cell Death Differ. 14:146-57, 2007.
8.
Hamacher-Brady
A, Brady NR, Gottlieb RA. Enhancing macroautophagy
protects against ischemia/reperfusion injury in
cardiac myocytes. J Biol Chem 281:29776-87,
2006.
9.
Hamacher-Brady
A, Brady NR, Gottlieb RA, and Gustafsson AB.
Autophagy as a protective response to Bnip3-mediated
apoptotic signaling in the heart (Addendum). Autophagy
2:307-9,
2006.
10.
Wall JA, Wei J, Ly M, Belmont P, Mardinale
JJ, Tran D, Sun J, Chen WJ, Yu W, Oeller
P, Briggs S, Gustafsson AB, Sayen MR, Gottlieb
RA, and Glembotski CC. Alterations in oxidative phosphorylation complex
proteins in the hearts of transgenic mice that
overexpress the p38
MAP kinase activator, MAP kinase kinase
6. Am
J Physiol Heart Circ
Physiol 291:H2462-72, 2006.
11.
Brady NR, Hamacher-Brady A, and Gottlieb RA. Proapoptotic Bcl-2
family members and mitochondrial dysfunction during
ischemia/reperfusion injury, a study employing
cardiac HL-1 cells and GFP biosensors. Biochim Biophys Acta – Bioenergetics. 1757:667-78, 2006.
12.
Baines CP, Kaiser RA, Purcell NH, Blair NS, Osinska H, Hambleton MA, Brunskill EW, Sayen MR, Gottlieb RA, Dorn GW, Robbins J, and
Molkentin JD. Loss of
cyclophilin D reveals a critical role for mitochondrial
permeability transition in cell death. Nature,
434:658-62,
2005.
13.
Gustafsson AB, Tsai JG, Logue SE, Crow MT, Gottlieb RA.
Apoptosis repressor with caspase recruitment
domain projects against cell death by interferfing
with Bax activation.
J Biol Chem. 279:21233-21238,
2004.
14.
Granville DJ, Tashakkor B,
Takeuchi C, Gustafsson AB, Huang C, Sayen MR,
Wentworth P Jr, Yeager M, and Gottlieb RA. Reduction
of ischemia and reperfusion-induced myocardial
damage by cytochrome P450 inhibitors. Proc
Natl Acad Sci
U S A 101:1321-6,
2004.
Ph.D. students:
Cyndi Perry (UCSD Molecular Pathology program)
Masters Students:
Wayne Liu, Sergey Gazarov, Joshua Millstone