Investigating Drivers of Antireward in Addiction Behavior with Anatomically Specific Single-Cell Gene Expression Methods

Summary

The combination of laser capture microdissection and microfluidic RT-qPCR provides anatomic and biotechnical specificity in measuring the transcriptome in single neurons and glia. Applying creative methods with a system's biology approach to psychiatric disease may lead to breakthroughs in understanding and treatment such as the neuroinflammation antireward hypothesis in addiction.

Abstract

Increasing rates of addiction behavior have motivated mental health researchers and clinicians alike to understand antireward and recovery. This shift away from reward and commencement necessitates novel perspectives, paradigms, and hypotheses along with an expansion of the methods applied to investigate addiction. Here, we provide an example: A systems biology approach to investigate antireward that combines laser capture microdissection (LCM) and high-throughput microfluidic reverse transcription quantitative polymerase chain reactions (RT-qPCR). Gene expression network dynamics were measured and a key driver of neurovisceral dysregulation in alcohol and opioid withdrawal, neuroinflammation, was identified. This combination of technologies provides anatomic and phenotypic specificity at single-cell resolution with high-throughput sensitivity and specific gene expression measures yielding both hypothesis-generating datasets and mechanistic possibilities that generate opportunities for novel insights and treatments.

Introduction

Addiction remains a growing challenge in the developed world^1,2. Despite major scientific and clinical advances, rates of addiction continue to increase while the efficacy of established treatments remains stable at best^3,4,5. However, advances in biotechnology and scientific approaches have led to novel methods and hypotheses to further investigate the pathophysiology of substance dependence^6,7,8. Indeed, recent developments....

Protocol

This study was carried out in accordance with the recommendations of Animal Care and Use Committee (IACUC) of Thomas Jefferson University. The protocol was approved by Thomas Jefferson University IACUC.

1. Animal model

1. House male Sprague Dawley (>120 g, Harlan, Indianapolis, IN, USA) rat triplets individually with free access to ethanol-chow (2 rats) or control-chow mixture (1 rat).
   NOTE: This representative experiment employed the Lieber-DeCarli protocol to study the neurobiology of alcohol withdrawal^25,26. Rat triplets consist of a three-rat....

Results

Validation of single-cell collection is performed visually during LCM procedures. Cell nuclei are assessed at the QC station. The cell type can be determined by emission of tagged fluorophore for that cell type and its general morphology. If non-desired cells have been selected on the cap, their genetic material can be destroyed with a UV laser at the QC station. Further validation by molecular analysis is also necessary. In this representative example¹⁶, two types of neurons were selected-tyrosin.......

Discussion

Alcohol use disorder remains a challenging disease to treat. Our group has approached this disorder by investigating antireward processes with a systems neuroscience perspective. We measured gene expression changes in single NTS neurons and microglia in an alcohol withdrawal time series¹⁶. The NTS was chosen for its prominent role in the autonomic dysregulation that occurs in alcohol withdrawal syndrome. We combine LCM with single-cell microfluidic RT-qPCR allowing for robust numbers of samples an.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
20X DNA Binding Dye	Fluidigm	100-7609	NA
2x GE Assay Loading Reagent	Fluidigm	85000802-R	NA
96.96 Dynamic Array IFC for Gene Expression (referred to as qPCR chip in text)	Fluidigm	BMK-M-96.96	NA
Anti-Cd11β Antibody	Genway Biotech	CCEC48	Microglia Stain
Anti-NeuN Antibody, clone A60	EMD Millipore	MAB377	Neuronal Stain
Anti-tyrosine hydroxylase antibody	abcam	ab112	Stain for TH+ neurons
ArcturusXT Laser Capture Microdissection System	Arcturus	NA	NA
Biomark HD	Fluidigm	NA	RT-qPCR platform
Bovine Serum Antigen	Sigma-Aldrich	B4287
CapSure Macro LCM Caps	ThermoFisher Scientific	LCM0211	NA
CellDirect One-Step qRT-PCR Kit	ThermoFisher Scientific	11753500	Lysis buffer solution components
CellsDirect Resuspension & Lysis Buffer Kit	ThermoFisher Scientific	11739010	Invitrogen
DAPI	ThermoFisher Scientific	62248	Nucleus Stain
DNA Suspension Buffer	TEKnova	T0221
Donkey anti-Rabbit IgG (H+L) ReadyProbe Secondary Antibody, Donkey anti-Rabbit IgG (H+L) ReadyProbe Secondary Antibody, Alexa Fluor 488	ThermoFisher Scientific	R37118	Seconadry Antibody
Exonuclease I	New Englnad BioLabs, Inc.	M0293S	NA
ExtracSure Sample Extraction Device	ThermoFisher Scientific	LCM0208	NA
FisherbrandTM Superfrost Plus Microscope Slides	ThermoFisher Scientific	22-037-246	Plain glass slides
GeneAmp Thin-Walled Reaction Tube	ThermoFisher Scientific	N8010611
Goat anti-Mouse IgG (H+L), Superclona Recombinant Secondary Antibody, Alexa Fluor 555	ThermoFisher Scientific	A28180	Seconadry Antibody
IFC Controller	Fluidigm	NA	NA
RNaseOut	ThermoFisher Scientific	10777019
SsoFast EvaGreen Supermix with Low Rox	Bio-Rad	PN 172-5211	NA
SuperScript VILO cDNA Synthesis Kit	ThermoFisher Scientific	11754250	Contains VILO and SuperScript
T4 Gene 32 Protein	New Englnad BioLabs, Inc.	M0300S	NA
TaqMan PreAmp Master Mix	ThermoFisher Scientific	4391128	NA
TE Buffer	TEKnova	T0225	NA
TempPlate Semi-Skirted 96-Well PCR Plate, 0.2 mL	USA Scientific	1402-9700	NA