The Effect of AMPK Activation on Cognitive FunctionJUAN C. RAMIREZ – AUGUST 4, 2016

Introduction to Aging and its Implications

1.1 Increase in Elderly Population and Complex Diseases

In the past century, we have seen a tremendous rise in human lifespan

A Graphic showing recorded and predicted numbers of elderly people in the US (U.S. Bureau of the Census)

1.2 Aging and Complex Diseases Overview

Aging constitutes the biggest risk factor in the onset of complex diseases and physiological decay

A Graphic showing proportion of elderly population with Alzheimer’s and other dementias (AA)

B Graphic showing proportion of elderly population with single and multiple diseases (CMS)

Mechanisms of Aging

2.1 Mechanisms of aging• Single gene mutations and simple interventions have been demonstrated to increase lifespan

•Notable interventions include:• Dietary Restriction (DR)• Mediation of mitochondrial dynamics• Activation of AMPK

2.2 Dietary Restriction and AMPK in Aging

• DR has been demonstrated to increase lifespan across species, including primates

• Molecular mechanisms mediating DR are a focus area in aging science

• AMP-Activated Kinase Protein (AMPK) has been shown to be upregulated in DR• AMPK has since been well-documented to extend

lifespan

A Graphic showing lifespan data for both well-fed nematodes and those subjected to DR (Win et al. 2013)

2.2 AMPK and Healthspan Extension

Highly conserved low energy sensor composed of three subunits

Activated AMPK

Assessing Nematode Cognitive Function

3.1 Memory Assay Quantify C. elegans learning ability to determine neuronal health in both treated and non-treated animals

Conditioning of worms in both a neutral stimulus (salt) and unconditioned stimulus (starvation) results in conditioned response (repulsion to salt)

3.2 Conditions

No preference No preference Aversive behavior

-NaCl-Food

+NaCl+Food

+NaCl-Food

3.3 Quantifying Memory in Nematodes

Chemotaxis Index (CI) measures attraction to salt

Memory Index (MI)

quantifies nematode

learning ability

3.4 Effect of CA AMPK on Learning

• Hypothesis: CA AMPK will promote higher learning ability in treated worm

• Result: CA AMPK worms demonstrate a nearly two-fold increase in learning ability

3.5 Effect of DR on Learning• eat-2 worms possess a mutation that prevents normal pharyngeal pumping of food• Mimics DR

•Hypothesis: eat-2 worms will also have greater learning ability than non-DR worms

•Results contradicted hypothesis, with eat-2 worms possessing roughly 50% of wild-type learning ability

•Bias of assay involves sensing of food, that which may not be available to eat-2 mutants

3.6 Forgetting Assays can provide further insights

•Among the chief hallmarks of aging is progressive memory loss

•A Forgetting Assay can quantify memory loss much like memory formation is assessed in a memory assay

•Progression of memory loss across worm strains, growth conditions, or pharmacological treatments grants insight into time-dependent phenotypes

Conclusions & Future Directions

4.1 AMPK supports extended cognitive ability; DR effect on memory remains unclear• Genetic activation of AMPK promotes increased learning in addition to extended lifespan • Suggests an AMPK-promoted maintenance/improvement of cognitive ability

•Dietary restriction provides mixed results, with more repeats necessary to verify conclusion• Development of alternative assay may be necessary

4.2 Future Directions• In order to further study these effects, we aim to:• Express CA AMPK in specific tissues, singling out

those responsible for lifespan extension and improved neurological function

• Activate AMPK via pharmacological intervention and compare the treated worms’ cognitive functions against recruitment method

• Measure nematode memory retention against time to further assess cognitive function

Phenformin

Activated AMPK

Mair LabFunding

Lab MembersWilliam Mair Emina TabakovicSydney Brumfield Heather WeirKristopher Burkewitz Yue ZhangSneha Dutta Carlos Silva GarciaCaroline Escoubas Caroline HeintzAnne Lanjuin

Thank You