Effect of Liraglutide Treatment on Inflammation and Oxidative Stress in Young and Old APP/PS1 and WT Mice

Supervisors: Dr. Christian Holscher Dr. Kerry Hunter

Geisa Nogueira SallesB00627190

Introduction

Liraglutide

Analogue of GLP-1 (glucagon-like peptide-1), hormone released in response to nutrients which potentiates insulin secretion and reduce blood glucose levels Approved for the treatment

of diabetes as an agent that promote insulin secretion (Lovshin and Drucker, 2009)

Treatment with insulin has been shown to improve brain function in humans (Okereke, O. I. et al., 2008)

Range of neuroprotective properties

Substantial anti-oxidant and anti- inflammatory effects in endothelial cells

Oxidative Stress in AD

Oxidative damage to DNA may play a role in normal aging and neurodegenerative diseases (Mecocci, P. et al, 2004)

Mechanisms associated to oxidative stress and free-radical reactions have a crucial role in the pathogenesis of AD, specifically, in the formation of plaques and tangles (Lyras L, et al. 1997)

8-Oxoguanine Common DNA lesion caused by reactive oxygen species, associated with neurodegeneration

Brain Inflammation in AD

Causes degeneration, disease progression and declines cognition

The number of microglia within neuritic plaques is increased

IBA-1 (ionized calcium-binding associated protein)

Macrophage/microglia marker

β-amyloid Microglia Inflammatory Response

ACTIVATES INITIALIZES

Methods

Sections of hipoccampus of these groups were cut in Cryostat

•Wild type Saline•Wild type Liraglutide•APP/PS1 Saline•APP/PS1 Liraglutide

9 and 15 month old female (n=6 for

each group) treated for 3 weeks

8 OxoGuanine Staining IBA-1 Staining

• Immunohistological experiment done with 1º and 2º ab• Chromogen was used to colour the sections• Pictures were taken in Zeiss® Axio Scope A1 (cortex for IBA-1 and dentate for 8OxoG)• Pictures were analysed with ImageJ®• Statistical analysis was done with Prism®, using One-way ANOVA

Aims

Compare the effects of Liraglutide in 9 and 15 month old APP/PS1 and WT mice

Determine if Liraglutide is able to

interfere and reduce brain inflammation and oxidative stress in APP/PS1 AD mouse model compared to WT mice

Results

% IBA-1 expression in mouse cortex of WT and APP/PS1 female mice (n=6 for each group) treated with Liraglutide (25nMol/Kg bw) or Saline (0.9% w,v NaCl) as control for 3 weeks. Values are the mean ± S.E.M *** p<0.001 compared to APP/PS1 Saline; ΔΔΔ p<0.001 compared to APP/PS1 Liraglutide

APP/SI1 Saline APP/SI1 Liraglutide

WT Saline WT Liraglutide

Results

% IBA-1 expression in mouse cortex of WT and APP/PS1 female mice (n=6 for each group) treated with Liraglutide (25nMol/Kg bw) or Saline (0.9% w,v NaCl) as control for 3 weeks. Values are the mean ± S.E.M *** p<0.001 compared to APP/PS1 Saline; ΔΔΔ p<0.001 compared to APP/PS1 Liraglutide

APP/SI1 Saline APP/SI1 Liraglutide

WT Saline WT Liraglutide

ResultsAPP/SI1 Saline APP/SI1 Liraglutide

% 8OxoGunine expression in mouse cortex of WT and APP/PS1 female mice (n=6 for each group) treated with Liraglutide (25nMol/Kg bw) or Saline (0.9% w,v NaCl) as control for 3 weeks. Values are the mean ± S.E.M *** p<0.001 compared to APP/PS1 Saline.

WT Saline WT Liraglutide

Results

% 8 OxoGuanine expression in mouse cortex of WT and APP/PS1 female mice (n=6 for each group) treated with Liraglutide (25nMol/Kg bw) or Saline (0.9% w,v NaCl) as control for 3 weeks. Values are the mean ± S.E.M * p<0.05 and ** p<0.01 compared to APP/PS1 Saline.

WT Saline

APP/SI1 LiraglutideAPP/SI1 Saline

WT Liraglutide

•No significant difference for IBA-1 between WT and APP/PS1 at 9 and 15 month old.•The microglia activation was not reduced with the treatment, since the inflammatory marker IBA-1 was not reduced.

DiscussionIBA-1

9 month old

IBA-1

15 month old

Activated microglia not only exert neuroprotective effects

but might also be detrimental for the survival of neuronal tissue

(Luo XG et al, 2010)

M1 macrophage: Produce pro inflammatory cytokines, TNFgama, IL-6, ILI2

M2 macrophage: Reduce inflammatory + adaptative TH1 response, producing anti inflammatory factors

•The oxidative stress presented significant reduction with the Liraglutide treatment in APP/S1 for both groups•Liraglutide has considerable anti-oxidant effect in the brain

Discussion8OxoGuanine

9 month old

8OxoGuanine

15 month old

Liraglutide treatment can reduce free radicals associated with typical lesions found in the brains of AD patients, therefore preventing:

damage to DNAprotein oxidation lipid peroxidation

(Christen, Y, 2000)

Conclusion Liraglutide may be effective in preventing

neurodegenerative processes in AD patients, since it prevent oxidative stress in the brain in young and old mice

For the microglia activation, the high expression of IBA-1 may be related to an overexpression of M2 macrophages, which produce anti-inflammatory factors

REFERENCESChristen, Y. (2000). Oxidative stress and Alzheimer disease. Am J Clin Nutr 2000 71: 621sKarran, E., Mercken, C., De Strooper, B. (2011). The amyloid cascade hypothesis for Alzheimer’s disease: an appraisal for the development of therapeutics. Nature Rev. Drug Discov., 10, 698-712.Lovell MA, Gabbita SP, Markesbery WR (1999) Increased DNA oxidation and decreased levels of repair products in Alzheimer ’s disease ventricular CSF. J Neurochem 72:771–776Lovshin, J. A., & Drucker, D. J. (2009). Incretin-based therapies for type 2 diabetes mellitus. Nature Reviews Endocrinology, 5(5), 262–269.Luo X.G., Ding Q, Chen D. (2010). Microglia in the aging brain: relevance to neurodegeneration. Molecular Neurodegeneration, 5.Lyras L, Cairns NJ, Jenner A, Jenner P, Halliwell B (1997) An assessment of oxidative damage to proteins, lipids, and DNA in brain from patients with Alzheimer ’s disease. J Neurochem 68:2061–2069Mecocci P, MacGarvey U, Beal MF (1994) Oxidative damage to mitochondrial DNA is increased in Alzheimer’s disease. Ann Neurol 36:747–751Okereke, O. I. et al. (2008). A profile of impaired insulin degradation in relation to late-life cognitive decline: a preliminary investigation. Int. J. Geriatr. Psychiatry 24, 177–182.Small, D. H., Cappai, R. (2006). Alois Alzheimer and Alzheimer’s disease: a centennial perspective, Journal of Neurochemistry, 99, 708-710.Wimo, A., Prince, M. (2010). World Alzheimer Report 2009: the global economic impact of dementia. Alzheimer’s Disease International.

References Christen, Y. (2000). Oxidative stress and Alzheimer disease. Am J Clin Nutr 2000 71: 621s Karran, E., Mercken, C., De Strooper, B. 2011. The amyloid cascade hypothesis for Alzheimer’s

disease: an appraisal for the development of therapeutics. Nature Rev. Drug Discov., 10, 698-712. Lovell MA, Gabbita SP, Markesbery WR (1999) Increased DNA oxidation and decreased levels of

repair products in Alzheimer’s disease ventricular CSF. J Neurochem 72:771–776 Lovshin, J. A., & Drucker, D. J. (2009). Incretin-based therapies for type 2 diabetes mellitus. Nature

Reviews Endocrinology, 5(5), 262–269. Luo XG, Ding JQ, Chen SD. Microglia in the aging brain: relevance to neurodegeneration.

Molecular Neurodegeneration. 2010;5 Lyras L, Cairns NJ, Jenner A, Jenner P, Halliwell B (1997) An assessment of oxidative damage to

proteins, lipids, and DNA in brain from patients with Alzheimer’s disease. J Neurochem 68:2061–2069

Mecocci P, MacGarvey U, Beal MF (1994) Oxidative damage to mitochondrial DNA is increased in Alzheimer’s disease. Ann Neurol 36:747–751

Okereke, O. I. et al. A profile of impaired insulin degradation in relation to late-life cognitive decline: a preliminary investigation. Int. J. Geriatr. Psychiatry 24, 177–182 (2008).

Small, D. H., Cappai, R. 2006. Alois Alzheimer and Alzheimer’s disease: a centennial perspective, Journal of Neurochemistry, 99, 708-710.

Wimo, A., Prince, M. 2010. World Alzheimer Report 2009: the global economic impact of dementia. Alzheimer’s Disease International.

http://link.springer.com/content/pdf/10.1007%2Fs004010100418 http://ajcn.nutrition.org/content/71/2/621s.full

Acessed in 14/04/2013