Alzheimer's study...

(I had this in my List, but it "disappeared". I could only find it again in the middle of a 200+ page PDF- so I am re-posting it here for my List)

ENDOCANNABINOIDS PREVENT LYSOSOMAL MEMBRANE DESTABILISATION EVOKED BY TREATMENT WITH β-AMYLOID IN CULTURED RAT CORTICAL NEURONES


J.J. Noonan, R. Tanveer, S. Cunningham, V.A. Campbell
Department of Physiology and Trinity College, Institute of Neuroscience, Trinity College, Dublin, Ireland

Alzheimer’s disease (AD) is a neurodegenerative disease characterised by the progressive deterioration of cognition and memory in association with the presence of senile plaques, neurofibrillary tangles and a massive loss of neurones. A major reason for the cognitive decline in AD is due to neuronal cell loss in the cerebral cortex and hippocampus (1). It is now understood that part of the neuronal death in AD is due to apoptosis. Lysosomal dysfunction has been implicated in a variety of pathogenic events that produce neurodegeneration.

It has recently emerged that destabilisation of the lysosomal membrane plays a vital role in the apoptotic pathway evoked by amyloid beta (Aβ) (2). Amongst the areas of research, the endocannabinoid system is emerging as a promising new target for treatment. It provides neuroprotection against excitotoxicity, ischemia, inflammation, and more significantly against the harmful affects of Aβ (3). The aim of this research was to explore the neuroprotective capacity of endocannabinoids in maintaining lysosomal membrane integrity, and in doing so, preventing the deleterious effects of apoptosis.

Cultured cortical neurones were prepared from one day old Wistar rats. To monitor lysosomal stability, cultured cortical neurones were incubated with acridine orange (5μg/ml) for 10 minutes followed by treatment with Aβ1-40 (2μM) ± the endocannabinoid, anandamide (AEA; 10nM) for 6 hours. Lysosomal permeability was measured by loss of fluorescence intensity at 633nm. Release of the lysosomal enzyme, cathepsin-L was measured using a commercially available kit, while cathepsin-D release was measured using BODIPY conjugated to pepstatin A. Lysosomal associated membrane proteins (LAMP1/2) expression was assessed by fluorescence immunocytochemistry and western immunoblotting.

Fluorescence intensity at 633nm, reflective of intact lysosomes, was reduced from 130±18.21in control cells to 51.7±10.02 (mean±SEM, p<0.01, ANOVA, n=5 observations) in cells treated with Aβ1-40. Co-treatment with AEA significantly increased this to 124.8±11.01, thereby preventing destabilisation of the lysosomal membrane. Cathepsin-L activity was increased from 3.7±0.54 (relative fluorescent units, mean±SEM, p<0.05, ANOVA, n=5) to 7.6±1.24 in cells treated with Aβ1-40 compared with those of control, and this was significantly reduced to 3.5±0.99 in cells co-treated with AEA. LAMP1 expression was significantly decreased to 1.74±0.080 (arbitrary units, mean±SEM, p<0.05, ANOVA, n=5) from 2.7±0.29 in cells treated with Aβ1-40 compared with control. This was prevented by co-treatment with AEA. LAMP2 expression was significantly increased from 3.7±0.15 (arbitrary units, mean±SEM, p<0.001, ANOVA, n=5) to 5.9±0.23 in cells treated with control compared to Aβ1-40, and this was reduced to 3.9±0.058 in cells co-treated with AEA.

We report that AEA prevents Aβ1-40 –induced lysosomal membrane permeability, and the subsequent release of the lysosomal enzymes, cathepsin-L and cathepsin-D. Similarly AEA prevents the Aβ1-40-evoked changes in LAMP1 and LAMP2 expression, suggesting it may act to stabilise the lysosomal membrane, and thus avert the apoptotic pathway. Modification of the apoptotic cascade by treatment with endocannabinoids could be a therapeutic strategy of prime importance for AD.



1. Terry RD et al., (1991) Physical basis of cognitive alterations in Alzheimer’s disease: synaptic loss is the major correlate of cognitive impairment. Ann Neurol 30: 572-580
2. Fogarty MP et al., (2008) A role for p53 in the beta-amyloid-mediated regulation of the lysosomal system. Neurobiol Aging
3. Campbell VA and Gowran A



Granny's translation -

Alzheimer’s is characterized by losing your memory and ability to think, plaque build-up in the brain, microscopic fiber tangles, and the death of brain cells mostly in the cerebral cortex and hippocampus parts of the brain. The brain cells die because a process called apoptosis. Parts of the cell, lysomes, become dysfunctional when amyloid beta poisons them. This has been shown to cause degeneration in brain cells.

Amyloid beta (which becomes amyloid plaque that gums up your brain) damages the skin of the lysome and that sets the whole mess off! The endocannabinoid system (ECS) has been shown to protect neurons, protect cells where there is a lack of blood (as in strokes or heart attacks), reduce inflammation, and more significantly, it protects against the harmful affects of amyloid beta /amyloid plaque. We wanted to see how endocannabinoids (that your body naturally makes) protect the lysomes and prevent the brain cells from dying.

We took rat brain cells and kept them alive in test tubes. We poisoned the cells with amlyloid beta and then treated some of them with anandamide (AEA), one of the endocannabinoids.

We measured how the lysomes reacted in several different ways.

The test results show that anandamide protected the lysomes. (You can dig through the numbers yourself if you are that interested!)

Anandamide (AEA) prevents the amyloid beta from messing up the lysomes, and that may prevent cell death by apoptosis. We think that fiddling with endocannabinoid levels may provide a new and important way to treat Alzheimer’s!




Granny