Science - USA (2020-02-07)

active caspase-6 staining, the degree of active
caspase-6 was increased in cirrhosis (Fig. 3D).
Moreover, whole-section scanning showed
that both active caspase-6 and TUNEL stain-

ing were located within the cirrhotic nod-

ule, indicating that caspase-6 might activate

apoptosis of hepatocytes in human cirrho-

sis (Fig. 3E).

An AMPK agonist and a caspase-6 inhibitor

therapeutically improve liver damage

To test the potential of AMPK as a therapeutic

target, we fed C57BL/6J mice with CD-HFD

Zhaoet al.,Science 367 , 652–660 (2020) 7 February 2020 5of9

Fig. 4. Both an AMPK agonist
and a caspase-6 inhibitor
therapeutically improve liver
damage.(AtoI) C57BL/6J mice
were fed CD-HFD for 6 weeks,
followed by intraperitoneal
injection of 25 mg/kg
A-769662 or vehicle daily for
2 weeks while fed continuous
CD-HFD. (A) Liver sections
stained TUNEL (red) and DAPI
(blue). Scale bar, 50mm. (B)
Quantification of TUNEL-positive
nuclei per field in (A);n=
7 mice. [(C) to (E)] Serum
ALT (C), AST (D), and ALP (E);
n= 7 mice. (F) H&E and
Sirius red staining of liver
sections. Scale bar, 100mm. (G)
Quantification of liver fibrosis
area (percent of total area) in
(F);n= 7 mice. (H) Liver
hydroxyproline;n=8mice.(I)
Expression ofTgfb,Timp1,
Col1a1,Col3a1,Pdgfa,Pdgfb,
Pdgfra,andDdr2in livers;
n=8mice.P< 0.05, Student’s
unpairedttest. (JtoL)Flox
and LAKO mice were fed
CD-HFD for 6 weeks, followed by
intraperitoneal injection of
5 mg/kg VEID or vehicle every
other day for 2 weeks while
continuously feeding. (J)
Liver sections stained TUNEL
(red) and DAPI (blue). Scale bar,
50 mm. (K) Quantification of
TUNEL-positive nuclei per
field in (J);n= 5 to 6 mice.
(L) Serum ALT;n=5to
6 mice. Mean ± SEM; P<0.05,
two-way ANOVA.

Vehicle

A-769662

200

300

400

500

ALT (U/L)

• 
  

Vehicle

A-769662

100

120

140

160

180

200

AST (U/L)

• 
  

Vehicle

A-769662

100

200

300

400

ALP (U/L)

• 
  

Vehicle

A-769662

H&E Sirius Red

Vehicle

A-769662

0

1

2

3

4

5

Fibrosis (% area)

• 
  

Vehicle

A-769662

0

200

400

600

Hydroxyproline

(ug/g liver)

• 
  

A-769662

Vehicle

TUNEL DAPI Merge Zoom

BC E

L

D

F

G

HI

K

A

J TUNEL DAPI Merge Zoom

VEID

Vehicle

VEID

Vehicle

Flox

LAKO

Vehicle

VEID

Flox LAKO

0

200

400

600

800

1000

ALT (U/L)

• 
  

• 
  

n.s.

• 
  

Vehicle

A-769662

0

20

40

60

80

TUNEL

+ cell/field

• 
  

Flox LAKO

0

50

100

150

TUNEL

+ cell/field

• 
  

• 
  
  
  
  • 
    
  
  
  
  

n.s.

Tgfb Col1a1 Col3a1 Pdgfa Pdgfb Pdgfra Ddr2

0.0

0.5

1.0

1.5

2.0

mRNA (A.U.)

• 
  

• 
  

* *

*

Vehicle

A-769662

Vehicle

VEID

RESEARCH | RESEARCH ARTICLE