Sample & Assay Technologies

Molecular Mechanisms of Neurodegeneration

Jesse Liang, Ph.D.

Sample & Assay Technologies Neurodegeneration

Neurodegeneration is featured by progressive dysfunction and death of cells in selected areas in the nervous system.

1. Alzheimer’s Disease (AD)2. Parkinson’s Disease (PD)3. Huntington’s Disease (HD)4. Multiple Sclerosis (MS)

• abnormal protein assemblies (protein misfolding)• oxidative stress• Late-onset cell death in adulthood• inflammation

Sample & Assay Technologies Selected Area of Changes

Overview of the anatomical locations and macroscopic and microscopic changes characteristic of the neurodegenerative disorders (The genetic epidemiology of neurodegenerative disease, J Clin Invest. 2005 June 1; 115(6): 1449–1457)

Sample & Assay TechnologiesOverview of Mutant Genes Causing Neurodegeneration

Sample & Assay Technologies Two Pathways to Clear Up Proteins

1. Ubiquitin – Proteasome

• This is the primary route cells use to degrade proteins.• Decreased proteasome activity is observed in

neurodegeneration. • Mutation of a deubiquitinating enzyme (ubiquitin carboxyl-

terminal hydrolase, UCHL1) in PD

2. Autophagy – Lysosome

• When proteins are poor proteasome substrates.

Sample & Assay Technologies Aging – The Greatest Risk Factor

The greatest risk factor for neurodegeneration is aging.

Genes that mediate oxidative stress responses and DNA damage repair constitute the largest class of genes up-regulated in aging.

Sample & Assay Technologies Aging – Oxidative Stress

• The highly abundant mitochondria in brain cells are a major site of generation and action of ROS (reactive oxygen species) / RNS (reactive nitrogen species) since the brain uses 20% of the inspired oxygen and 90% of the consumed oxygen to produce energy. The neuronal cells are thus particularly sensitive to oxidative stress.

• Mitochondria are both generators of and targets for reactive species. Mitochondria generate ROS from a number of different redox centers in the respiratory chain and other metabolic pathways. Therefore oxidative stress is inseparably linked to mitochondrial dysfunction.

• Mitochondrial turnover is dependent on autophagy (meaning “self-eating”), which declines with age and is frequently dysfunctional in neurodegeneration. mTOR functions as an inhibitor of the initiation step of autophagy. Defining the stages of autophagy and its progress in a tissue or cell is important for understanding its function and regulation.

Sample & Assay Technologies Aging – DNA Repair

Mutations in DNA surveillance and DNA repair enzymes are associated with neurodegeneration.

Sample & Assay Technologies The Major Apoptotic Pathways in Neurodegeneration

Mark F. Mehler and Solen Gokhan. Trends Neurosci. (2000) 23, 599–605

Sample & Assay Technologies Other Signaling Pathways

• Wnt• Notch• Akt• NFκB• CREB

The Wnt signaling network interacts with and regulatesa number of neurogenic (e.g. Notch), cell adhesion (e.g. cadherins, integrins), cell cycle (Myc, cyclin D1) and viability (e.g. Akt, JNK) pathways that mediate numerousneurodevelopmental processes.

Sample & Assay Technologies Neurodegeneration is a Novel Class of Development Disorders

Neurodegenerative diseases may represent fundamental disorders of neurogenesis and neural development.

Sample & Assay Technologies Inflammation in Alzheimer’s Disease

There is a remarkable convergence in the mechanisms responsible for the sensing, transduction, and amplification of inflammatory responses that result in the production of neurotoxic mediators.

Mechanisms Underlying Inflammation in Neurodegeneration. Cell (2010) 140, 918–934.

Sample & Assay Technologies Inflammation in Parkinson’s Disease

Sample & Assay Technologies Inflammation in Multiple Sclerosis

* A Role of the Estrogen Receptor in Suppression of Inflammationhttp://www.sabiosciences.com/pathwaymagazine/minireview/neuroinflam.php

Sample & Assay Technologies Focused Neuronal Genomics – 5 Technologies

1. mRNA gene expression

2. microRNA expression

3. Methylation screening

4. Mutation detection

5. Gene copy number alteration

Sample & Assay Technologies Gene Expression at mRNA Level – PCR Arrays

• Oxidative stress• Unfolded protein response (ER stress)• DNA damage• Synaptic plasticity• Alzheimer’s disease• Parkinson’s disease• Huntington’s disease• Multiple sclerosis• Amino acid metabolism• Autophagy• Neuronal ion channels• Neurotransmitters & receptors• Neurotrophins• Dopamine & serotonin pathway• GABA & glutamate• Neurogenesis• Pain

http://www.sabiosciences.com/neuroscience.php

Sample & Assay Technologies PCR Array Introduction

84 pathway-specific genes of interest

5 housekeeping genes

Genomic DNA contamination control

Reverse transcription controls (RTC) n=3

Positive PCR controls (PPC) n=3

Sample & Assay Technologies microRNA Expression – microRNA PCR Arrays

• Neurological development and disease

• Apoptosis

• Cell development & differentiation

• Brain cancers

• Serum and plasma miRNAs

http://www.sabiosciences.com/mirna_pcr_array.php

Sample & Assay Technologies Gene Methylation Screening – Methylation PCR Arrays

• Apoptosis

• Wnt signaling

• Notch signaling

• Mental disorders

http://www.sabiosciences.com/dna_methylation_array.php

Sample & Assay Technologies Gene Copy Number Alterations – CNV PCR Arrays

• Alzheimer’s disease

• Intellectual disability

• Glioma

• Birth defects

• Autism spectrum disorders

• Schizophrenia

http://www.sabiosciences.com/copynumberarray.php

Sample & Assay Technologies Mutation Detection – Mutation PCR Arrays

• PI3K-Akt pathway

• Receptor tyrosine kinases (RTKs)

• Brain cancer

http://www.sabiosciences.com/mutationproductlist.php?tab=arraysbypathway

Sample & Assay Technologies We Also Provide Services – Simply Send Your Samples

• RNA extraction

• DNA extraction

• Illumina chips

• All sorts of PCR Arrays

http://www.sabiosciences.com/servicecore.php

Sample & Assay Technologies Contact Information

Jesse LiangEmail: jesse.liang@qiagen.com

Technical Support: 1-888-503-3187Email: support@sabiosciences.com

Check Webinar Calendar:http://www.sabiosciences.com/seminarlist.php

Regular PCR Arrays: April 4(Thursday)microRNA PCR Arrays: March 15/22/29 (Fridays) Methylation PCR Arrays: March 28 (Thursday)Mutation PCR Arrays: April 9 (Tuesday)Copy Number Variation PCR Arrays: April 18 (Thursday)