1. Assessment of Hepatic Insulin
Signaling in a Murine Model for
Alström Syndrome
Ayla Kanber, Boston University
The Jackson Laboratory
Summer Student Program Symposium
August 10, 2015

2. What is Alström Syndrome?
-Recessive, progressive, fatal ciliopathy
-1018 patients worldwide
Clinical features:
-Obesity
-Type 2 Diabetes
-Fatty Liver Disease
-Hyperinsulinemia
-Sensory vision and hearing loss
-Dilated cardiomyopathy
-Nephronophthisis
-Liver steatosis
-Excessive fibrosis in all tissues
-Death from cardiac, renal, or liver failure by the third
decade of life
No treatment available for patients

4. Alms-Ntr
Acetylated α-tubulin
4pi image: Localization of ALMS1 to basal bodies of ciliated cells
~Ciliated cells function throughout the body; normal cilia assembly in
AS
~Exact function of protein is unknown
~Previous studies show that ALMS1 may be involved in docking proteins
hTERT-RPE1 ciliated cells
ALMS1 proteins are localized to the basal bodies
of ciliated cells
cell
Cilia
Adapted from:

5. The Alms1 mouse model recapitulates many of the clinical
features observed in human patients
~Alms1Gt/GT mouse model created by a *gene trap in intron 13 of
Alms1
~A gene trap is used to purposefully insert mutations
randomly into the mammalian genome
Alms1Gt/GT mouse model and littermate control at 10 months old

6. Graphs of body weight (g) and plasma insulin values (time course)
Weeks Weeks
BodyWeight(g)
Insulin(ng/ml)
Favaretto et al, 2014
Alms1-/-
Control
Preliminary Findings: Obesity and
hyperinsulinemia phenotypes present at ~8 weeks
old in mutant mice

7. Graph of ALT values (time course)
0
100
200
300
400
500
600
6W 12W 18W 24W 36W
Alms1-/- control
Weeks
IU/L
Preliminary Findings: ALT values are high in mutant
mice at ~12 weeks, indicative of liver dysfunction

8. Extensive Portal Fibrosis in Postmortem ALMS
liver specimen
J. Marshall
Normal liver
Trichrome stain
Alström Syndrome liver
Farrington et al., 2010 Clin Exp Gastroenterol
Trichrome stain

9. Main Goals
— Study livers of 6 week old mice, before the onset of
obesity, hyperinsulinemia, and other phenotypes
— Why? Liver failure is one of the common causes of
death for Alström Syndrome patients.
— Determine whether or not liver insulin resistance
occurs because of a defect in the insulin-signaling
pathway
— Determine if liver insulin resistance is a primary
defect of Alström Syndrome

10. Mutant, A/AControl, WT
6M
Hepatosteatosis, an abnormal retention of lipid deposits, is
expressed in 6 month old mutants

11. Progression of Liver Disease in Alström Syndrome
from Hepatosteatosis to Hepatosteatitis
9M 12M 21M 24M
Blue fibers indicate lymphocyte
infiltrations
Red collagen fibers indicate
fibrosis

12. Comparison of Liver Weights at 6 weeks
and 6 months old
0
1
2
3
4
5
6
6 weeks old 6 months old
AverageLiverweight(g)
Age
*Male only
WT
Alms1Gt/GT
~Retention of lipids in mutant mice at 6 months old
causes fatty liver, and high liver weight compared to
control mice

13. Mutant, IBA1, 8 monthsControl, IBA1, 8 months
Kupffer cells
Kupffer cells are activated in 8 month old mutants to
repair liver damage

14. Control, GFAP, 8 months Mutant, GFAP, 8 months
Activated
stellate cells
PV
Stellate cells are activated in 8 month old mutants to
repair liver damage

15. Emamian, 2012
Confusing and Complicated AKT Pathway

16. The Insulin Signaling Pathway leads to the
phosphorylation of AKT
Studying pAKT will show if there is a defect in this pathway in 6 week
old mutant mice before obesity and hyperinsulinemia phenotypes
Jung et al., 2014

17. 6 week old insulin-injected control and mutant
mice express more phosphorylated AKT than
saline-injected mice
Western Blot Analysis

18. Hepatic insulin resistance is not a
primary defect of Alström Syndrome!
Conclusion: The successful phosphorylation of AKT in
6 week old insulin-injected Alms1 mice shows that the
mutant mice are not insulin resistant in the liver.
RelativepAKT/β-actin
insulin *p-value <0.05 is significant
WT
Alms1Gt/
GT

19. Future Research?
— Study the insulin signaling pathway downstream of
AKT where there could be defects that cause
hepatic insulin resistance
— Potential Therapeutic
Intervention

20. Acknowledgements
— Special thanks to
Jürgen K. Naggert, Ph.D.
Gayle Bouchard-Collin, M.S.
— I would like to thank all of the Naggert/Nishina lab for welcoming me and
supporting me during this program.
— Thank you to the benefactors of the Summer Student Program. This Summer
Student Fellowship was supported by the Beverly Coleman Endowment.
— Thank you to the Jackson Laboratory.
— Thank you Korstanje family and Summer Students for making this the best
summer ever!