ac#vin a & fop of interest statement & disclaimer • aris n. economides is an employee of...
TRANSCRIPT
Ac#vinA&FOP
ArisN.Economides([email protected])RegeneronPharmaceu#cals&RegeneronGene#csCenter
FOP-Friends,Manchester,UK
May2016
Conflict of interest statement & Disclaimer
• ArisN.EconomidesisanemployeeofRegeneronPharmaceu9cals,andholdscommonstockinthecompany.
• Allthedatainthispresenta9onhasbeenprocuredusingmice.Wedonotyetknowhowthisdatatranslatestohumans.
• ThemajorityofthedatathatyouwillbeseeinghasbeenpublishedbyHatsell,Idone,etal,inScienceTransla9onalMedicineonSeptember2,2015.
A mouse model of FOP presents with heterotopic bone at sites reminiscent of those observed in FOP patients
Baseline 2 wks 4 wks 10 wks
Noteconnec9on
ofheterotopicbonetoexis9ngbone
4 wks
Newconnec9ontoexis9ngbone,establishedas
HObonegrows
6 wks 10 wks
HOhasundergoneremodeling
m#1
m
#2
New centers of heterotopic bone appear over time and these continue to make connections with the skeleton
and other heterotopic bone lesions
Red arrows indicate direction of HO growth HO connects to original bone between 4-6 weeks after initiation of the model HO combines with original bone at the femur & tibia …but maintains boundary, unlike at ilium (site-specific?)
sacrum
tail
ilium
tibia
femur
HO
Nanditha Das & LiQin Xie
Thisgene#callyaccuratemousemodelofFOPhasallowedusto
explorehowthemutantreceptor(ACVR1R206H)drives
heterotopicossifica#on
Ac#vinAnormallyactsasacompe##veinhibitorofBMP-inducedsignalingfromACVR1“Neofunc#on”ofACVR1FOPvariants:perceivingAc#vinsasagonists
Hatsell,Idone,etal.ScienceTrans.Med.(2015)PMID26333933
confirmedbyHinoetal,PNAS(2015)PMCID:PMC4687587
ACVR1 (ALK2) is part of the “lock” in a lock & key mechanism that controls many biological processes
Type IR:ACVR1(ALK2)
Type IIR:ACVR2A, 2B, BMPR2 Smad1/5/8
phosphorylation
FKBP12 FKBP12
BMP
• Thinkofthislikealock&keymechanism:• The“ligands”arethekeys,the“receptors”arethelock.• Whenligandsbindtothereceptortheyini9ateacascadeofevents(thatisreferredtoas
signaltransduc9on)–consideritequivalenttounlockingthelock.• InthoseofuswhoarenotFOPpa9entsthislock&keymechanismpar9cipatesinnormal
9ssuerepairprocesses.• InFOPpa9ents,someofthe9methisalock&keymechanismalsopar9cipatesinnormal
9ssuerepairprocesses,butsomeofthe9meitdrivestheforma9onofheterotopicbone.• Asthepar9cular“lock”thatACVR1ispartofcanbeopenedbymany“keys”–i.e.ligands
–wesetouttofindoutwhichistherelevantkeyinFOP,againusingthemousemodel.
6
6 14
13
Treatment with ACVR2A- plus ACVR2B-Fc (that bind many BMP family ligands) block formation of heterotopic bone
untr
eate
d
AC
VR2A
/B-F
c tr
eate
d Think of ACVR2A-Fc and ACVR2B-Fc as molecular vacuum cleaners for BMP family ligands!
ACVR2A-Fc and ACVR2B-Fc bind the Activins, a subset of the TGFß/BMP family of ligands
Ligand
ACVR2B-Fc (193) ACVR2B-Fc (221) ACVR2A-Fc (232) Orbi-Velos Orbi-Velos Bruker MALDI
GDF8 ✓ ✓ ✓ GDF11 ✓ ✓ ✓ BMP10 ✓ ✓ ✗
Activin A ✓ ✓ ✓ Activin B ✓ ✓ ✓ Activin C ✓ ✓ ✓ Activin E ✓ ✓ ✓
GDF2 ✓ ✓ ✗ TGF-β-1 ✓ ✗
• Exp 193; Multiple injections of Protein, bleed on Day 14 • Exp 221: Single injection of Protein, bleed on Day 4 • Exp 232: HDD of ACVR2A-Fc DNA, bleed on Day 14
Activins are expressed by innate immune system cells during the initial stages of an inflammatory process
c/o Protein Expression Sciences
FOP-causing ACVR1 variants have gained the ability to respond to Activin A
ACVR1[R206H] is a gain-of-function variant with unprecedented properties: • ACVR1[R206H] retains the ligand-binding properties of wild type ACVR1, but gains the ability to
respond to a class of ‘non-canonical’ ligands – the Activins. • Activins normally act as inhibitors of BMP signaling from this receptor (a property newly recognized). • This is the first example wherein an intracellular domain amino acid change in a type I Receptor
qualitatively alters the way it perceives ligands.
p-Smad2/3
Activin
Type I: ACVR1B ACVR1C
Type II: ACVR2A ACVR2B BMPR2
Activin
R206H variant
Type I: ACVR1[R206H] ± ACVR1
p-Smad1/5/8
Activin BMP
Type I: ACVR1
p-Smad1/5/8
BMP
Activin A induces heterotopic ossification only in Acvr1[R206H] mice
4
Acvr1[R206H]/+mice WTmice71 2
943 10
5 6 11 12
Salin
e
collagenspon
ge
implan
t
Act
ivin
A
colla
gen
spon
ge
impl
ant
rhB
MP2
co
llage
n sp
onge
im
plan
t
Joanna Jimenez, Kalyan Nannuru
8
• 2weeksa`erimplanta9onofrhAc9vinA-impregnatedcollagensponges,HOwasobservedatthesiteofimplanta9oninAcvr1[R206H]mice(butnotinWTmice).
• HOisobservedinbothAcvr1R206HandWTmicewhenimplantedwithrhBMP2-impregnatedcollagensponges.• InsalinecollagenspongesimplantedgrouponeAcvr1[R206H]mousedevelopedHOat7thrib;therewasnoHOin
WTmice.
CONFIDENTIAL 11
#1-7–Isotypecontrol#9-17–Ac9vinAAb#18-25–ACVR2A-Fc
Mice #s 1-7 (isotype control-treated cohort), 20 and 23 (ACVR2A-Fc cohort) have heterotopic bone forming at 3 weeks (arrows) Mice treated with an anti-Activin Ab do not develop heterotopic bone (out to 6 weeks). The scan shown here was taken at 3 weeks.
Lily Huang, Xialing Wen
Preclinical data: Heterotopic bone forms in several locations in isotype control treated mice, but is absent in
mice treated with an antibody that blocks Activin A
CONFIDENTIAL 12
#1-7–Isotypecontrol#9-17–Ac9vinAAb#18-25–ACVR2A-Fc
Mice #s 1-7 (isotype control-treated cohort), 20 and 23 (ACVR2A-Fc cohort) have heterotopic bone forming at 3 weeks (arrows) Mice treated with an anti-Activin Ab do not develop heterotopic bone (out to 6 weeks). The scan shown here was taken at 3 weeks.
Lily Huang, Xialing Wen
CONFIDENTIAL 13
#1-7–Isotypecontrol#9-17–Ac9vinAAb#18-25–ACVR2A-Fc
Mice #s 1-7 (isotype control-treated cohort), 20 and 23 (ACVR2A-Fc cohort) have heterotopic bone forming at 3 weeks (arrows) Mice treated with an anti-Activin Ab do not develop heterotopic bone (out to 6 weeks). The scan shown here was taken at 3 weeks.
Lily Huang, Xialing Wen
Preclinical data: Heterotopic bone forms in several locations in isotype control treated mice, but is absent in
mice treated with an antibody that blocks Activin A
A working model for the formation & propagation of HO in FOP
Inflamma#on-inducingevent
(trauma,infec9on,orevennormal9ssuerepair)
Recruitment&‘ac#va#on’ofinnateimmuneresponse
cells(Macrophages,MastCells)
ExpressionofAc#vinA(trauma,infec9on,orevennormal
9ssuerepair)
Ac9va9onofosteogenicprogramin
9ssue-residentprogenitorcells
HeterotopicOssifica#on
HeterotopicBone
‘Initiating Phase’
A working model for the formation & propagation of HO in FOP
SecondaryInflamma#on-inducingevent:theheterotopic
boneitself!
Recruitment&‘ac#va#on’ofinnateimmuneresponse
cells(Macrophages,MastCells)
ExpressionofAc#vinA(trauma,infec9on,orevennormal
9ssuerepair)
Ac9va9onofosteogenicprogramin
9ssue-residentprogenitorcells
HeterotopicOssifica#on
HeterotopicBone
‘Propagation & Expansion
Phase’
Heterotopicboneconnectedtotheskeleton:andsubjecttoskeletal
homeostasis
A working model for the formation & propagation of HO in FOP
SecondaryInflamma#on-inducingevent:theheterotopic
boneitself!
Recruitment&‘ac#va#on’ofinnateimmuneresponse
cells(Macrophages,MastCells)
ExpressionofAc#vinA(trauma,infec9on,orevennormal
9ssuerepair)
Ac9va9onofosteogenicprogramin
9ssue-residentprogenitorcells
Nuclea#onofnewHO&
expansionofexis#ngHO
“CreepingOssifica#on”
‘Propagation & Expansion
Phase’
…a vicious circle?
Heterotopicboneconnectedtotheskeleton:andsubjecttoskeletal
homeostasis
