Tg APP23 mouse! Microglial Migration!

Transcription

1 Serge Rivest Neuroscience Laboratory CHU de Québec Research Center, Department of Molecular Medicine, Laval University, 2705 Laurier Blvd., Québec, Canada

2 The Amyloid Code!

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4 Tg APP23 mouse! Microglial Migration!

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8 In 2013, Neuron was celebra4ng 25 years of publishing exci4ng neuroscience and this paper has been selected as the most influen4al paper for year 2006 ( hcp:// five- years).

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10 Microglia of bone marrow origin migrate towards endogenous β-amyloid of APP Swe /PS1 mice. 5 mo 6 mo 9 mo

11 Alzheimer Mouse Mutation in the APP and PS1 genes

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13 Defect in M1, not M2!!

14 CCR2 KO!

15 Lentivirus-expressing CCR2 in BMSCs rescues! the cognitive deficit in APP/CCR2 KO mice!

16 CCR2-gene! Delivery in! Cells of the bone marrow in CCR2 KO! APP mice!!

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19 The deposition of Aβ in APP/PS1/Cx3cr1 mice is ageand vessel-dependent

20 Different patterns of Aβ deposition in cortical arteries and veins

21 Monocytes are selectively attracted to small Aβ aggregates in veins APP/PS1/Cx3cr1 gfp/+ (5 mo) APP/PS1/Cx3cr1 gfp/+ (9 mo) Cx3cr1 gfp/+

22 Monocytes are selectively attracted to small Aβ aggregates in veins

23 Crawling monocytes can internalize Aβ and circulate back to the bloodstream

24 Crawling monocytes can internalize Aβ and circulate back to the bloodstream

25 Deposition of vascular Aβ is dynamic in young mice and correlates with monocyte crawling

26 Crawling cells inside Aβ + veins are mainly Ly6C low monocytes

27 Reduction of Ly6C low monocytes increases Aβ deposition

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29 Conclusions Ly6C lo monocytes are a?racted to and crawl selecbvely onto Aβ- posibve veins Monocytes take up Aβ and circulate back to the bloodstream Aβ deposibon and eliminabon by monocytes is dynamic in veins of young APP/PS1 mice AblaBon of Ly6C lo monocytes in APP/PS1 mice increases Aβ load

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31 Neuron! Yong-Rivest!

32 Toll-like receptor 4 stimulation with the detoxified ligand monophosphoryl lipid A improves Alzheimer s disease-related pathology Jean-Philippe Michaud a, Maxime Hallé b, Antoine Lampron a, Peter Thériault a, Paul Préfontaine a, Mohammed Filali a, Pascale Tribout-Jover b, Anne-Marie Lanteigne b, Rachel Jodoin b, Christopher Cluff c, Vincent Brichard d, Rémi Palmantier d, Anthony Pilorget b, Daniel Larocque b,1, and Serge Rivest a,1 a Neuroscience Laboratory, Department of Molecular Medicine, Centre Hospitalier Universitaire de Québec Research Center, Laval University, QuébecCity,QC, Canada G1V 4G2; b GlaxoSmithKline Vaccines, Laval, QC, Canada H7V 3S8; c GlaxoSmithKline Vaccines, Hamilton, MT 59840; and d GlaxoSmithKline Vaccines, B-1330 Rixensart, Belgium Edited by Shizuo Akira, Osaka University, Osaka, Japan, and approved December 19, 2012 (received for review September 1, 2012) Alzheimer s disease (AD) is the most common cause of dementia worldwide. The pathogenesis of this neurodegenerative disease, currently without curative treatment, is associated with the accumulation of amyloid β (Aβ) in brain parenchyma and cerebral vasculature. AD patients are unable to clear this toxic peptide, leading to Aβ accumulation in their brains and, presumably, the pathology associated with this devastating disease. Compounds that stimulate the immune system to clear Aβ may therefore have great therapeutic potential in AD patients. Monophosphoryl lipid A (MPL) is an LPS-derived Toll-like receptor 4 agonist that exhibits unique immunomodulatory properties at doses that are nonpyrogenic. We show here that repeated systemic injections of MPL, but not LPS, significantly improved AD-related pathology in APP swe /PS1 mice. MPL treatment led to a significant reduction in Aβ load in the brain of these mice, as well as enhanced cognitive function. MPL induced a potent phagocytic response by microglia while triggering a moderate inflammatory reaction. Our data suggest that the Toll-like receptor 4 agonist MPL may be a treatment for AD. innate immunity microglial cells monocytes phagocytosis inflammation has not been tested in humans. We propose that the age-related defects in immune cell function (11) commonly found in aging diseases such as AD (12) can be reconciled with a prophagocytic phenotype, yet mildly proinflammatory, which may lead to an improved clearance of Aβ. Our data demonstrate that chronic, systemic administration of MPL ameliorates AD-like pathology by decreasing the cerebral Aβ load through the stimulation of the phagocytic capacity of innate immune cells. Results MPL Drives a Distinct TLR4 Stimulation from LPS. MPL is derived from the LPS of the Gram-negative bacteria Salmonella minnesota R595 by three main chemical modifications: (i) elimination of the core oligosaccharide, (ii) hydrolysis of the 1-phosphate from the reducing end glucosamine, and (iii) removal of the acyl chain from the 3-position of the disaccharide (Fig. 1 A and B). The absence of the 1-phosphate on the MPL molecule was suggested to weaken the dimerization of TLR4/MD2 (myeloid differentiation factor-2) (13). This presumably induces a structural change in the TLR4 receptor complex that alters the recruitment of the adaptor proteins to the intracellular domain (13). Such a structural change may account for the distinct signaling properties of MPL, which NEUROSCIENCE

33 Comparison of LPS and MPL extracted from Salmonella minnesota R595. (i) eliminabon of the core oligosaccharide (ii) hydrolysis of the 1- phosphate from the reducing end glucosamine (iii) removal of the acyl chain from the 3- posibon of the disaccharide

34 TLR4- specific ac=va=on of NF- κb and AP- 1 in HEK 293 cells TLR4- MD2- CD14 TLR2

35 Phosphoryla=on kine=cs of key TLR pathway of MPL vs LPS in microglia

36 MPL induces a low inflammatory response in microglia

37 MPL s=mulates ac=n reorganiza=on

38 Phagocytosis of fluorescent E.coli beads and Aβ oligomers

39 MPL upregulates Scavenger receptors- A in microglia

40 In vivo uptake of Aβ oligomers in monocytes

41 Low immune ac=va=on following MPL injec=on

42 MPL triggers only a weak TLR2 mrna induc=on in the brain

43 MPL triggers the expansion of blood monocytes in mice

44 APP swe /PS1 mice treatment - 3 month- old APP swe /PS1 mice - 12 consecu=ve i.p. injec=ons once a week - MPL (50 μg, 130 μl) LPS (3,5 μg, 130 μl) PBS (130 μl) - Pathology analysis at 6 month- old

45 MPL treatment reduces Aβ plaques

46 MPL treatment reduces soluble Aβ

47 MPL treatment reduces cogni=ve deficits in APP swe /PS1 mice

48 Conclusions - MPL induces a potent phagocy=c response in microglia and monocytes (p38 pathway and SR- A) - MPL triggers a low inflammatory response - MPL reduces Aβ loads and restricts cogni=ve deficits of APP swe /PS1 mice.

49 Neuron! Yong-Rivest!

50 Activation of systemic innate immune cells is a very efficient approach to clear vascular and brain amyloid load and prevent cognitive decline in Alzheimer's disease. This may also be the case for other brain diseases associated with the accumulation of toxic extracellular proteins (SOD1, alpha-syn, ).

51 Who did the work? Marc-André Bellavance, M.Sc. Dr. Alain Simard Dr. Antoine Lampron Dr. Gaëlle Naert Jean-Philippe Michaud, M.Sc. Paul Préfontaine. M.Sc. Dr. Maxime Hallé (GSK) Dr. Daniel Larocque (GSK)

52 $$$ CIHR, CRC, Neuroscience Canada, Brain Repair Program (Dr. Wee Yong, PI), MS Canada Team Grant (Dr. Peter Stys, PI), Canadian Stroke Network, GSK-Vaccines.

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