HD InsightsInsights of the

YearMichael Geschwind, MD, PhD UCSF Memory and Aging Center

Most Influential Insights

HSG 2016: DISCOVERING OUR FUTURE

In imaging and biomarkers…Altered PDE10A expression detectable early before symptomatic onset in HDPresented by: Flavia Niccolini, PhDIn the clinic…Identification of genetic factors that modify clinical onset of Huntington’s diseasePresented by: Jong-Min Lee, PhD

Institute of Psychiatry, Psychology and Neuroscience (IoPPN)Department of Basic and Clinical Neuroscience

ALTERED PDE10A EXPRESSION DETECTABLE EARLY BEFORE

SYMPTOMATIC ONSET IN HUNTINGTON’S DISEASENiccolini F, Haider S, Reis Marques T, Muhlert N,

Tziortzi AC, Searle GE, Natesan S, Piccini P, Kapur S, Rabiner EA,

Gunn RN, Tabrizi SJ and Politis MNeurodegeneration Imaging Group

www.nig-politis.com

PDE10Awww.nig-politis.com

extracellular

intracellular

DA

DA

STRIATUM

ACD1RD2R

β γ

PKA

ATP cAMP

DA DACA

DA DA

DADADA

PDE10A

DARP32-CREB

Gsα

DADA

CA

DADA DA

DA DA

DA

DA

DA

DA

DA

PDE10A & HDwww.nig-politis.com

o Preclinical research in transgenic HD animal models suggests a direct effect of mutant huntingtin on PDE-10A expression via the alteration of transcription, synthesis and trafficking

Hu et al., 2004; Leuti et al., 2013

Leuti et al., 2013 Hebb et al., 2004

PDE10A inhibition & HD

www.nig-politis.com

Giampà et al., 2009, 2010

AIMwww.nig-politis.com

To study a unique cohort of Early Premanifest HD gene

expansion carriers (HDGECs) and investigate the expression

of PDE10A enzyme using [11C]IMA107 PET molecular

imaging

Participantso 12 early premanifest HDGECs who were the furthest from

the predicted disease onset

o 12 aged and sex-matched healthy controls

Study procedures - 1

Motor: UHDRS TMS

Cognitive:

CANTAB® : o Psychomotor speed: RTI o Episodic memory: PAL &

PRMo Working memory &

executive function: OTSo Language processing: GNT

Neuropsychiatric :• PBA-S• BDI-II• HDRS

Clinical assessments:

Functional capacity:• UHDRS-TFC• UHDRS-IS• UHDRS-FAS• SF-36

www.nig-politis.com

Study procedures - 2Imaging assessments:• One [11C]IMA107 PET scan (no arterial metabolites, 90 min) • One 3-T MRI scan (T1-weighted; FGATIR; FLAWS; DTI 32 Dir BLIPUP &

BLIPDOWN)

PET analysis• Frame-by-frame realignment for movement correction• SRTM – cerebellum reference, coreg, BPND

MRI analysis• FreeSurfer’s image analysis suite (version 5.3.0 )• VBM morphometry SPM8 software package

www.nig-politis.com

Mansur et al., 2016

www.nig-politis.com

Clinical characteristicsHealthy controls Premanifest HDGECs

No (Sex) 12 (8M/4F) 12 (7M/5F)

Age (years ± SD) 40.0 (±6.2) 41.1 (±7.5)

CAGr (± SD) [range] - 41.8 (±1.3) [40-44]

DBS1 (± SD) [range] - 254.4 (± 46.8) [153-323]

90% p to onset2 (years ±SD) [range] - 25 (±6.9) [17-43]

UHDRS TMS (±SD) 0 (±0) 0 (±0)

UHDRS DCL (±SD) - 0 (±0)

1Disease burden score: age x (CAG length–35.5); 290% p to onset: Paulsen et al., 2008

Clinical assessmentswww.nig-politis.com

Healthy controls Premanifest HDGECs

P values

UHDRS-TMS (±SD) 0 (±0) 0 (±0) -

UHDRS-TFC (±SD) 13 (±0) 13 (±0) -

UHDRS-IS (±SD) 100 (±0) 100 (±0) -

UHDRS-FAS (±SD) 25 (±0) 25 (±0) -

SF-36 (±SD) 94.71 (±2.2) 92.28 (±4.4) 0.12

Motor and functional measures

Clinical assessmentswww.nig-politis.com

Healthy controls Premanifest HDGECs

P values

Episodic MemoryPAL Memory score (±SD)

21.00 (±2.5) 20.08 (±2.9) 0.97

PAL Stages completed on 1st trial (±SD)

6.00 (±0) 6.08 (±0.7) 0.79

PRM No correct (±SD) 21.40 (±2.2) 21.67 (±2.3) 0.99

PRM Mean latency to correct (±SD) [msec] 1686.92 (±533.9) 2159.50 (±610.1) 0.10

Working memory & Executive FunctionsOTS Mean latency to correct (±SD)

13668.93 (±9688) 13176.69 (±8334) 0.75

OTS Problems solved on 1st choice (±SD) 15.60 (±2.7) 17.10 (±2.5) 0.29

Cognitive measures - 1

Clinical assessmentswww.nig-politis.com

Healthy controls Premanifest HDGECs

P values

Psychomotor SpeedSimple movement time (±SD) [msec]

431. 24 (±99.5) 371.41 (±90.4) 0.32

Simple reaction time (±SD) [msec]

299.80 (±60.5) 319.34 (±44.5) 0.43

5-choice movement time (±SD) [msec]

408.78 (±82.7) 368.10 (±71.8) 0.25

5 choice reaction time (±SD) [msec]

331.00 (±61.8) 324.78 (±111.1) 0.47

Language processing

GNT Total errors (±SD) 8.00 (±6.8) 5.67 (±2.3) 0.29

Cognitive measures - 2

Clinical assessmentswww.nig-politis.com

Healthy controls Premanifest HDGECs

P values

PBA apathy (±SD) 0 (±0) 0.08 (±0.3) 0.54

PBA affect (±SD) 0 (±0) 1 (±1.8) 0.20

PBA irritability (±SD) 0 (±0) 1.6 (±2.2) 0.13

BDI-II (±SD) 2.4 (±2.9) 4.7 (±5.3) 0.40

HDRS (±SD) 1.4 (±2.1) 4.2 (±5.5) 0.30

Neuropsychiatric measures

Freesurfer MRI volumetric analysiswww.nig-politis.com

Healthy controls Premanifest HDGECs

P values

Caudate (±SD) [mm3] 3803.08 (±428.9) 3538.58 (±571.9) >1.0

Putamen (±SD) [mm3] 5587.29 (±529.5) 4996.00 (±771.0) 0.31

Pallidum (±SD) [mm3] 1454.29 (±147.2) 1287.50 (±135.06) 0.07

Thalamus (±SD) [mm3] 8085.13 (±540.3) 7336.29 (±948.03) 0.22

Hippocampus (±SD) [mm3]

4284.38 (±324.35) 4124.38 (±441.5) >1.0

Amygdala (±SD) [mm3] 1670.08 (±130.4) 1664.92 (±226.7) >1.0

Accumbens (±SD) [mm3]

583.25 (±122.34) 488.92 (±111.47) 0.43

Ventricle (±SD) [mm3] 7774.25 (±2621.1) 10199.83 (±2898.0) 0.34

All means are corrected for total intracranial volume

PDE10A PET analysiswww.nig-politis.com

LAYER 1: [11C]IMA-107 BPND based on anatomically defined ROIs

LAYER 2: [11C]IMA-107 BPND based on connectivity-based parcellations of ROIs (limbic, cognitive and sensorimotor striatum) according to cortical-striatal connectivity profiles

LAYER 3: [11C]IMA-107 BPND based on connectivity-based parcellations of ROIs (striatonigral/striatopallidal internal and striatopallidal external projecting segments of striatum) based on striatal connections with GPe and SN/GPi

[11C]IMA107 BPND based on anatomy

www.nig-politis.com

% changes

Caudate −33.0%

Putamen −30.5%

Ventral striatum −16.9%

Pallidum −25.6%

Motor Thal Nuclei +34.5%

Sub Nigra +9.0%

www.nig-politis.com

[11C]IMA107 BPND based on anatomy

`

www.nig-politis.com

[11C]IMA107 BPND based on cortical connectivity

HCs pHDGECs P values % change

Limbic (mean±SD) 0.83 (±0.3) 0.65 (±0.2) >0.10 -11.3%

Cognitive (mean±SD) 1.30 (±0.3) 1.06 (±0.3) >0.10 -18.5%

Sensorimotor (mean±SD) 1.95 (±0.3) 1.29 (±0.4) <0.001 -34.0%

www.nig-politis.com

[11C]IMA107 BPND based on D1 and D2 pathways

HCs pHDGECs P values % change

D1 direct pathway (mean±SD) 1.61 (±0.3) 1.09 (±0.3) 0.008 -32.6%

D2 indirect pathway (mean±SD) 1.73 (±0.4) 1.15 (±0.3) <0.001 -33.9%

Correlations between PDE10A and clinical characteristicswww.nig-politis.com

Probability of symptomatic conversionwww.nig-politis.com

Microglia

Politis et al., 2011

r=0.809P=0.022

D2 receptor

van Oostrom et al., 2009

r=0.25P=0.034

PDE10Ar=0.82P=0.001

PDE10A in manifest HDGECs

www.nig-politis.com

5 Manifest HDGECs (HD1-4)UHDRS-TMS = 37

DBS = 426 [18F]JNJ42259152

Ahmad et al., 2014 -63%

-71%

PDE10A in HDGECswww.nig-politis.com

8 Early Manifest HDGECs (HD1-2)

3 Premanifest HDGECs (mean of 12 years from

predicted onset) [18F]MNI-659 Russell et al., 2014

PDE10A changes in HDGECswww.nig-politis.com

Russell et al., 2016

6 manifest and 2 premanifest HDGECs

[18F]MNI-659 PDE10A mean annualized

rates of decline

−5.8% −6.9%

−16.6

Conclusions

o Bidirectional changes in PDE10A expression in premanifest HDGECs, which are associated with the risk of symptomatic conversion, and are detectable up to a mean of 25 years before the predicted onset of clinical symptoms

o PDE-10A expression could be a biomarker of striatal MSNs integrity and [11C]IMA107 PET may be a useful tool for future trials of disease-modifying therapeutics aiming to delay the onset and slow the progression of HD

www.nig-politis.com

THANK YOUNeurodegeneration Imaging Group

Marios PolitisHeather Wilson

Tayyabah YousafGennaro Pagano

George DervenoulasKonstantinos Diamantopoulos

Sotirios PolychronisJuan Bonfante

www.nig-politis.com

KCL NIHR BRC

Inclusion/Exclusion Criteriawww.nig-politis.com

Inclusion:12 Early Premanifest HDGECs:• Age 21–75 years • Capable of giving informed consent• HD gene carriers with ≥ 40 CAG repeats • UHDRS TMS of 0 indicating lack of motor signs with UHDRS DCL = 0

12 Healthy Controls:• Ability to give informed consent• No history of any psychiatric or neurological diseasesExclusion:• No medications with known action on PDE10A• Presence of psychiatric and/or other neurological disorders • Standard for PET and MRI scanning (e.g. pregnancy, cancer, etc)• Standard for the ligand (e.g. coffee, tea, papaverine etc)

The Huntington Study Group, 1996

CANTAB testsPsychomotor SpeedRTI – simple & 5-choice

Language ProcessingGNT

Working memory & Executive FunctionOTS

www.nig-politis.com

Episodic MemoryPAL PRM

PDE10A in HDGECswww.nig-politis.com

33-34% PDE-10A signal loss in D1 and D2 projecting striatal segments

35% increases of PDE-10A signal in the motor thalamic nuclei

Genetic modifiers of HD

Jong-Min Lee, Ph.D. Assistant Professor

on behalf of the GeM-HD Consortium

Center for Human Genetic Research, Massachusetts General Hospital

Department of Neurology, Harvard Medical School

Genetically supported targets can double the success rates of clinical trials

Nature Genetics, 2015, 47, 856

Cell, 1993, 72, 971

Cell, 2015, 162, 516

Cell, 1993, 72, 971

Discovery of the cause of HD

Autosomal dominant

HD

Normal

The cause of HD was described in 1993 paper

Duff beer is HTT CAG expansion mutationBeer belly caused by drinking beer is HD

Partial list

Outcomes of 1993 cloning paper: Therapeutic developments

CRISPR strategy for perfect allele specificityPAM-altering SNPs

PromotorNCG NGT

gRNA 1 gRNA 2Nor

mal

chro

mos

ome

Nor

mal

C

AG

Transcriptionstart

Promotor NGGNGGgRNA 1 gRNA 2E

xpan

ded

CA

G

Mut

ant

chro

mos

ome

PAM-altering SNP PAM-altering SNP

Large deletion

Permanent inactivation of mutant allele by CRISPR

B. CAG region in DNA

Mutant

Normal

GM01169 TSCC 1

Normal

MutantGM01169 TSCC 1

C. CAG region in RNA

D. Total HTT protein

Mutant

GM01169 TSCC 1

Total

GM01169 TSCC 1

E. Mutant HTT protein

A. Targeted DNA

~700 bp

GM01169 TSCC 1

F. ACTB protein

GM01169 TSCC 1

~44kb deletion

Normal

Mutant

Normal HTT RNA

Mutant HTT RNAx

Nature Reviews Genetics Nature Reviews Neurology

Human Molecular Genetics

Outcomes of 1993 cloning paper: CRISPR treatment strategy

2015 HD genetic modifier paper

Genetic modifiers of HD

Comparing two groups of beer loversDuff beer is HTT CAG expansion mutationBeer belly caused by drinking beer is HDTV time is a genetic modifier

Age at onset is determined by HTT CAG repeat length and modifiers

40 45 50 55

20

40

60

80

CAG

Age

at o

nset

28 y

ears

10 CAGs

~ 30

yea

rs

Therapeutic potential of modifiers

Steps to identify HD genetic modifiers by GWA2.

Gen

otyp

ing

3. A

ssoc

iatio

n an

alys

is(e

xam

ples

)

Genome-wide SNP genotyping and genotype imputation

CAG

Age

at o

nset

(AO

)

Dis

tanc

e to

exp

ecte

d A

O(R

esid

ual)

1. P

heno

typi

ng

CAG

Dis

tanc

e to

exp

ecte

d A

O(r

esid

ual)

Exp

ecte

d A

O

Res

idua

l

0 1 2SNP minor allele count

Continuous analysis

Genotype A Genotype C

Phenotype:Early 200 80

Phenotype:Late 200 120

Dichotomous analysis

Sig

nific

ance

Identification of genetic modifiers of HD through GWA: CAG 40-55

Suggestive significance (p-value < 0.00001)

3 genome-wide significant signals and numerous suggestive loci

Genome-wide significance (p-value < 0.00000005)

2 independent genome-wide significant modifier signals at Chr15C

ondi

tiona

l ana

lysi

sS

ingl

e S

NP

ana

lysi

s

Effect of green SNP was removed

Effect of red SNP was removed

Genome-wide significant modifier signals at Chr8C

ondi

tiona

l ana

lysi

sS

ingl

e S

NP

ana

lysi

s

Effect of red SNP was removedEffect of red SNP was removed

0 2 4 6 8

R-squared (%)

0 0.1 0.2 0.3

Frequency of significance(density)

Freq

uenc

y of

R-s

quar

ed(d

ensi

ty)

Sig

nific

ance

(-lo

g10(

p-va

lue)

)

Grey, top SNPOrange, SNPs p < 0.00001Blue, SNPs p < 0.0001Green, SNPs p < 0.001Red, SNPs p < 0.01Purple, SNPs p < 0.05

0

1

0

2

0

3

0

4

0

5

0

6

0

0 0

.5

1

1.5

2

0 2 4 6 8

More to find in the genome

HD modifier GWA results (GeM MOA) are available at HDinHD.org

Journal of Huntington’s Disease

Identified mother nature’s experiments that resulted in modification of age at onset

Genome-wide significant loci: chromosome 15 and 8

Numerous suggestive loci were also discovered

The causal modifier variation / gene is not yet unequivocally known

Pathway analysis implicated DNA maintenance and mitochondria-related pathways

Follow-up genetic analysis and molecular experiments are on going

Genetics increases success rate of clinical trials

Identification of the cause of HD made gene targeting approaches possible

Discovery of genetic modifiers may contribute to the development of disease-delaying treatments

Summary

Michael ChaoKawther Abu ElneelTammy GillisDiane LucenteJayalakshmi MysoreMarisa Ramos

Denise Harold, CardiffPeter Holmans, CardiffLesley Jones, CardiffSeung Kwak, CHDIRichard Myers, BUMichael Orth, UlmVanessa Wheeler, CHGR, MGHMarcy MacDonald, CHGR, MGHJames Gusella, CHGR, MGH

Samples and dataHuntington Study GroupHD-MAPS CollaborationPREDICT-HD Study of the HSGREGISTRY Study of the EHDNMIGEN Consortium for control data

Acknowledgements

Funding

GeM-HD Consortium

Authors from HSG

HSG’s contribution to genetic study will lead to:

more samples, more phenotypes

more discoveries

being more successful in HD clinical trials