Tricyclic Antidepressants Promote Ceramide Accumulation to Regulate Collagen Production in Human Hepatic Stellate Cells.
Activation of hepatic stellate cells (HSCs) in response to injury is a key step in hepatic fibrosis, and is characterized by trans-differentiation of quiescent HSCs to HSC myofibroblasts, which secrete extracellular matrix proteins responsible for the fibrotic scar. There are currently no therapies to directly inhibit hepatic fibrosis. We developed a small molecule screen to identify compounds that inactivate human HSC myofibroblasts through the quantification of lipid droplets. We screened 1600 compounds and identified 21 small molecules that induce HSC inactivation. Four hits were tricyclic antidepressants (TCAs), and they repressed expression of pro-fibrotic factors Alpha-Actin-2 (ACTA2) and Alpha-1 Type I Collagen (COL1A1) in HSCs. RNA sequencing implicated the sphingolipid pathway as a target of the TCAs. Indeed, TCA treatment of HSCs promoted accumulation of ceramide through inhibition of acid ceramidase (aCDase). Depletion of aCDase also promoted accumulation of ceramide and was associated with reduced COL1A1 expression. Treatment with B13, an inhibitor of aCDase, reproduced the antifibrotic phenotype as did the addition of exogenous ceramide. Our results show that detection of lipid droplets provides a robust readout to screen for regulators of hepatic fibrosis and have identified a novel antifibrotic role for ceramide.
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.
Jennifer Y
JY
Chen
Health Science Center, Stony Brook University, Stony Brook, NY USA.
Benjamin
B
Newcomb
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.
Chan
C
Zhou
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.
Joshua V
JV
Pondick
Division of Surgical Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA USA.
Sarani
S
Ghoshal
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.
Samuel R
SR
York
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.
Daniel L
DL
Motola
Health Science Center, Stony Brook University, Stony Brook, NY USA.
Nicolas
N
Coant
Health Science Center, Stony Brook University, Stony Brook, NY USA.
Jae Kyo
JK
Yi
Health Science Center, Stony Brook University, Stony Brook, NY USA.
Cungui
C
Mao
Division of Surgical Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA USA.
Kenneth K
KK
Tanabe
National Jewish Health, Denver, CO USA.
Irina
I
Bronova
National Jewish Health, Denver, CO USA.
Evgeny V
EV
Berdyshev
Division of Surgical Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA USA.
Bryan C
BC
Fuchs
Health Science Center, Stony Brook University, Stony Brook, NY USA.
Yusuf
Y
Hannun
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.
Raymond T
RT
Chung
Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA.|Harvard Stem Cell Institute, Cambridge, MA 02138 USA.
Alan C
AC
Mullen
D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D002518:Ceramides / Q000378:metabolism*; D003094:Collagen / Q000096:biosynthesis*; D055808:Drug Discovery / Q000379:methods; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D055166:Hepatic Stellate Cells / Q000187:drug effects* / Q000378:metabolism*; D057166:High-Throughput Screening Assays; D006801:Humans; D008103:Liver Cirrhosis / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D058628:Myofibroblasts / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D000929:Antidepressive Agents, Tricyclic; D002518:Ceramides; D003094:Collagen