Part I – Learning from O’Hara by AMUZA’s users abroad

Part I – Learning from O’Hara by AMUZA’s users abroad

Amuza team member and product manager for O’Hara Behavioral Testing Solutions, Taylor Clark, travels to Japan to learn more about the applications of O’Hara products from their users.

For over 40 years, O’Hara has been developing and manufacturing equipment for behavioral experiments in Japan. Their products are currently used by over 150 researchers at universities, research institutes, and industrial labs across Japan.

Taylor Clark, Product Manager for O’Hara in the US, traveled to Japan to visit and learn from the researcher’s who have been working with O’Hara products. Her first stop – Tokyo University!

Here’s what she had to say:

First, I had the pleasure of visiting Dr. Masanori Matsuzaki’s laboratory in the Department of Physiology at Tokyo University School of Medicine.

Dr. Matsuzaki’s lab is interested in information processing in the Motor Cortex during motor skills learning. They apply several different techniques including two-photon imaging, optogenetics, and electrophysiology in behaving mice and marmosets to monitor and manipulate neural circuits in Motor Cortex that are involved in the initiation and execution of motor actions.

Currently, Dr. Matsuzaki’s lab is using the TaskForcer in combination with two-photon imaging of mice implanted with cranial windows, in order to monitor calcium dynamics of GCaMP (a genetically encoded calcium indicator) infected neurons in the Motor Cortex during skilled learning.

In speaking with Dr. Telada, assistant professor in Dr. Matsuzaki’s lab about the TaskForcer, here’s what he had to say:
“We needed a behavioral apparatus that would allow us to perform longitudinal imaging of the same neuronal populations over time during learning, which is why we chose to use the TaskForcer.”

“With the TaskForcer, we are able to consistently get precise neural recordings during imaging sessions while the mice perform a manual lever pull task.”

“We have now been using the TaskForcer in combination with a custom made two-photon microscope we built that enables super wide-field imaging. This has allowed us to simultaneously image neurons in both primary and secondary motor cortices during motor skills learning.”

Pictured is their TaskForcer setup underneath a two-photon microscope

To learn more about Dr. Matsuzaki’s research, check out his lab’s website.

To see selected publications using the TaskForcer please visit our TaskForcer product page.

Stay tuned for an update from my next destination!

Teaching Mice to Train Themselves : The Scoop on O’Hara’s New Behavioral Testing System

Teaching Mice to Train Themselves : The Scoop on O’Hara’s New Behavioral Testing System

Understanding how neural circuits give rise to behavior is one of the most sought after questions in Neuroscience. With O’Hara’s new behavioral testing system, finding an answer just got easier

O’Hara teamed up with researcher Dr. Andrea Benucci at the RIKEN Brain Science Institute in Japan to develop a high-throughput and fully automated system, The Self Head-Restraining Platform, to simultaneously assess mouse behavior and neurophysiology.

Mice learn to voluntarily self-fix their heads for a reward, enabling neural recording simultaneously during behavior.

Training head-fixed mice to perform complex tasks is extremely labor and time-intensive, leaving little time for actual research.

“Previously, training just one mouse took about 15 hours of a researcher’s time. Now, with twelve setups we are down to less than one-and-a-half hours.” – Andrea Benucci.

Using the Self Head-Restraining Platform, mice can engage in operant tasks at-will, without any intervention from the experimenter. The system has already been used to effectively train 100 mice.

In addition to the platform being high-throughput, mice learn to self-stabilize their heads,enabling an easy transition to in vivo examination of neural dynamics during behavior.

“Normally we see a decline in mouse performance or other incompatibilities when moving from highly-trained behaviors to different types of experiments for brain recordings, but that doesn’t happen with our system,” says Benucci.

Learn more about the Self Head-Restraining Platform by visiting https://amuzainc.com/operant-learning-self-restraining-platform/

Eicom AtmosLM Microdialysis Used in Developing Pharmacokinetic Models of Therapeutic Antibody Distribution in the Brain

Eicom AtmosLM Microdialysis Used in Developing Pharmacokinetic Models of Therapeutic Antibody Distribution in the Brain

The brain is a challenging target for therapeutic monoclonal antibodies (mAbs), nanobodies, antibody drug conjugates (ADCs), and other drugs. The blood brain barrier prevents many drugs with otherwise good absorption profiles from crossing into the brain, and also complicates attempts to model how drugs are distributed within the brain.

Prof. Dhaval Shah and PhD student Hsueh-Yuan Chang of the University at Buffalo study the pharmacokinetics/pharmacodynamics (PK/PD) of therapeutic antibodies and ADCs. Their lab recently used the Eicom AtmosLM (large molecule) microdialysis system as a way to quantitate a mAb in multiple brain regions simultaneously, generating data to underpin pharmacokinetic models for the disposition of mAbs in rats (1,2). They found that tissue homogenate and lumbar cerebrospinal fluid samples do not make good proxies for predicting mAb concentrations at their sites of action within the parenchyma of the brain. They also found that the lateral ventricles and the blood-CSF barrier may be an important route for mAb entry.

How Large Molecule microdialysis works

AtmosLM is a push-pull microdialysis system for measuring the levels of large proteins and peptides, as opposed to the catecholamines and other small molecules typically measured by microdialysis. AtmosLM features unique probes that incorporate vents to equalize the pressure inside the membrane of the probe with the outside atmosphere. This prevents ultrafiltration and yields more consistent analyte recovery rates than other push-pull systems. It has been widely used to study levels of Abeta, Tau, synuclein, lipidated ApoE particles, cytokines, and other molecules.

Microdialysis based PK modeling

Amuza spoke with Hsueh-Yuan (Luke) Chang about how he used AtmosLM in this project, and he also shared several tips for other users of AtmosLM.

Amuza: Could you explain how your PBPK (physiologically-based pharmacokinetic) model can be used by those studying the use of mAb based drugs in the brain?

Hsueh-Yuan: Our current version of the PBKP model is developed to capture nonspecific mAb distribution in the brain and different regions of the brain. It can help to quantify the correlation between mAb in CSF and mAb in brain ISF. It may help to quantify the amount of mAb entering brain parenchyma versus brain CSF compartments.

While the nonspecific mAb PBPK model has not incorporated target binding or receptor-mediated transcytosis yet, both novel delivery mechanisms and target binding kinetics can be mechanistically added into current basic version of PBPK model.

The final version of PBPK model for mAb may provide an a priori prediction of mAb distribution in the human brain by inputting kon/koff of values of mAb, receptor/target concentration in the brain. The validation of this prediction could be tested in rodents and primates.

Amuza: Central nervous system (CNS) concentrations of mAbs are often determined by taking whole brain homogenate samples or cerebrospinal fluid (CSF) samples from the lumbar region. What are these methods missing?

Hsueh-Yuan: They do not provide direct information of the mAb concentration at the site-of-action as we mentioned in the introduction of the paper. There are many studies suggesting mAb concentrations are different between CSF and ISF.

More important, mAb accumulation within brain capillary cells has been reported in some studies that work with endogenous receptor binding to enhance brain uptake of mAb.

Shah lab insights for using AtmosLM

Amuza: I’d also like to ask you a few questions about using our AtmosLM system.

You used siliconized sample tubes to prevent adsorption of antibodies in your samples to the plastic. Would blocking the tubes by rinsing with BSA work as well?

Hsueh-Yuan: Positive. However, the storage of low concentration IgG microdialysates requires 0.1-0.15% BSA. BSA is compatible with ELISA. For LC/MS, the BSA method should be replaced.

Amuza: Do you think endogenous IgG could be used similarly to an internal standard to suggest whether or not a microdialysis experiment is working correctly?

Hsueh-Yuan:  Yes, ELISA methods can quantify rat, mouse, or human IgG specifically. They can serve as an endogenous IgG reference for calculating in vivo recovery. Hemoglobin can be used, too.

Amuza: During in vitro tests, you were very careful when balancing the flow between the syringe pump (push) and the peristaltic pump (pull), adjusting the peristaltic pump until the ratio of fluid pumped in/out of the probe stayed in the range of 97 – 103%.

What happens if fluid recovery is outside of this range?

Hsueh-Yuan: Then convection [bulk flow of solutes and solvent across a membrane due to a pressure imbalance] will happen.

Amuza: This is indeed a problem. Your paper (1) found that recovery rates were strongly changed when the flow was not properly balanced. This data is available in the supplementary material.

How did you measure the amount of fluid recovered in each sample?

Hsueh-Yuan: By measuring their net weight.

Amuza: With AtmosLM probes, this can also be accomplished by visually monitoring the flow exiting the probe during in vivo experiments. If the peristaltic pump is pulling fluid out of the probe faster than the syringe pump is pushing fluid in, air will enter the system through the vent in the probe and be visible as bubbles in the tubing. If instead the syringe pump is pushing more fluid than the peristaltic pump is removing, the excess fluid will exit the probe through the vent hole. The vent hole is downstream from the membrane, and does not interfere with microdialysis.

Amuza: What suggestions do you have for others using AtmosLM to study antibody concentrations?

Hsueh-Yuan: 

  • Endogenous IgG or another internal reference should be measured to validate that the BBB is intact.
  • Fresh CSF perfusion buffer should be used. BSA may precipitate when sitting at room temperature.
  • Samples should be analyzed ASAP due to low concentration (or prepare a standard curve on the same day and store them with samples together).
  • Always check the inlet and outlet of the probe before connecting the probe to the push-pull system.

Amuza: Do you have future projects in mind for large molecule microdialysis?

Hsueh-Yuan: Yes. We have been working on several projects using AtmosLM microdialysis.

 

  1. Chang, H. Y., Morrow, K., Bonacquisti, E., Zhang, W., & Shah, D. K. (2018, August). Antibody pharmacokinetics in rat brain determined using microdialysis. In MAbs (Vol. 10, No. 6, pp. 843-853). Taylor & Francis.https://doi.org/10.1080/19420862.2018.1473910
  1. Chang, H. Y., Wu, S., Meno-Tetang, G., & Shah, D. K. (2019). A translational platform PBPK model for antibody disposition in the brain. Journal of pharmacokinetics and pharmacodynamics, 1-20.https://doi.org/10.1007/s10928-019-09641-8
Acetylcholine Neurochemical Involvement in Gulf War Illness

Acetylcholine Neurochemical Involvement in Gulf War Illness

For approximately 200,000 US veterans, the 1991 Persian Gulf War marked the beginning of their experience with Gulf War Illness (GWI). GWI encompasses a cluster of chronic symptoms including memory and cognitive problems, fatigue, and fibromyalgia.

GWI has long been associated with a combination of several possible contributory factors: the stress of deployment, altered immune function, and exposure to acetylcholinesterase inhibitors (AChEI), but the exact cause or causes have remained elusive. The AChEI pyridostigmine bromide (PB) was administered to soldiers as a prophylactic against the risk of nerve agent weapons, but many veterans were also exposed to AChEI based pesticides, further complicating the etiology of this illness.

To elucidate the relationship between these factors, Dr. Victoria Macht, her advisor Prof. Lawrence Reagan, and colleagues at the University of South Carolina School of Medicine studied rats exposed to pyridostigmine bromide and repeated restraint stress. The rats were then given either an immune challenge or an acute immobilization stress challenge during in vivo microdialysis. It is the first study to use an in vivo method (microdialysis) to show that PB changes the response of the central cholinergic system to both stress and immune challenges, and does so in a brain region specific manner.

By measuring acetylcholine levels via microdialysis and subsequent HPLC-ECD, they found that cholinergic responses were attenuated in the PFC and hippocampus after immobilization stress. Lipopolysaccharide (LPS) was administered as an immune challenge, after which cholinergic responses were attenuated in the hippocampus but not the PFC. These results indicate that PB and stress interact to shift the cholinergic response to future psychological and immunological stressors, providing a potential mechanism for the persistent and exacerbated cognitive symptoms evidenced in soldiers with GWI.

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Mike Churchill: What story do the different responses to the immune challenge and the immobilization challenge tell?

Victoria Macht: By using two different types of challenges, we were able to test both the diversity and consistency of effects of PB and stress on the cholinergic system. LPS is a novel challenge which specifically elicits a response from the innate immune system. The immobilization challenge is more of a psychological stressor, and as it shares some similar qualities with the prior restraint stress, this allowed us to test if rats with PB and restraint stress had impaired neurochemical adaptations to recurrent stressors.

MC: How might these results relate to changes in fear memory and cognitive function?

VM: ACh is an important regulator for a variety of factors in fear memory including coordination of local circuits to help with sensory and cortical processing of stimuli as well as the consolidation process. Interestingly, regional differences in the cholinergic response of the PFC and hippocampus to immobilization stress suggested that PB impairs cortical processing of novel stressful stimuli and impairs the neurochemical adaptation to recurrent stressful stimuli. In our fear conditioning studies, we similarly found impairments in the way PB and stress interacted to impair context and cue related retrieval. This suggested to us that impairments in the function of the cholinergic systems impacts a variety of psychological stressful stimuli, indicating that this is a global deficit in cognitive function rather than a specific deficit to only one type of stressor.

MC: How do the microdialysis results relate to the tests for inflammation you ran?

VM: ACh is really fascinating because while it is not only central in learning and memory, it is also an important negative regulator for the inflammatory response via α7 nicotinic ACh receptors. We found that PB blunted the central cholinergic response to an innate immune challenge, which could suggest an exacerbated chronic inflammatory response in the brain. Interestingly, these microdialysis results for acetylcholine parallel some of our findings with peripheral inflammatory markers. Peripheral levels of c-reactive protein were elevated after the LPS challenge in rats which had received PB, suggesting a dysregulated inflammatory response. While we need to confirm these results with cytokine levels in the brain, our results suggest that impaired cholinergic feedback to inflammatory stimuli could underlie some of the changes in the sensitivity of the immune system which are evident in clinical populations with GWI.

MC: Does PB have to cross the BBB to cause these effects?

VM: It does not. There has been a big debate on this topic. One suggestion was that stress caused a leaky barrier, allowing PB to get through. However, tests on this have been inconsistent on this. What our studies demonstrate is that PB changes the function of the central cholinergic system regardless of whether it is able to get through the BBB.

MC: What will be the next steps for this project?

VM: Prof. Reagan will continue the project: measuring cytokine responses in the brain to see if they match peripheral cytokine responses. There is also an opportunity to see if aging exacerbates the decline of the cholinergic responses and cognitive deficits in our model of GWI. The goal would be to see if animal models of GWI can predict further changes in veterans as they age, and plan treatment accordingly. We have a unique opportunity with this population for the preclinical research on treatments to get ahead of the patient population as they age.

MC: How did you like using the Eicom HTEC HPLC-ECDs in Prof. Jim Fadel’s lab?

VM: It is amazing! I can’t imagine having done these projects without it, and I miss using it.  We used the system daily for two years to measure acetylcholine without any real problems. It made my dissertation a much more pleasant experience!

MC: Had you used HPLCs before using the HTEC?

VM: We used a different system before but it was not reliable, so when it was working people felt they had to immediately run all of their samples before it went down again, and watch it all of the time when it was running.

MC: How many samples do you think you ran over the course of this project?

VM: That makes my head spin! We looked at both ACh and glutamate, in two brain regions, each rat underwent microdialysis 2 separate days, there were approximately 8 animals per group, and 4 groups. So at least 3500 samples – plus the pilot study! Plus there were other studies going on during this time which were also using the HTEC.

MC: Where is your career taking you next?

VM: I am now doing a postdoc at UNC Chapel Hill, working with Prof. Fulton Crews, studying the long term effects of binge drinking in adolescents. Interestingly, while this is a different clinical population, changes in the cholinergic system and innate immune system are also common features here.

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The article appears in the April issue of Brain, Behavior, and Immunity:

Pyridostigmine bromide and stress interact to impact immune function, cholinergic neurochemistry and behavior in a rat model of Gulf War Illness
V.A. Macht, J.L. Woodruff, E.S. Maissy, C.A. Grillo, M.A. Wilson, J.R. Fadel, L.P. Reagan
doi: 10.1016/j.bbi.2019.04.015

Optogenetics Resources, Guides, and Protocols

Optogenetics Resources, Guides, and Protocols

 

We would like to share some of the many resources our customers have found useful for planning their optogenetics projects. Please post comments if you know of more resources we should include – we will update this list regularly.

Starting From Scratch

For neuroscientists, Karl Deisseroth’s Optogenetics Resource Center is perhaps the best first stop when planning your experiment. The Deisseroth lab provides optogenetics related  DNA cassettes and vectors to the optogenetic research community, as well as training and workshops for in in-vivo optogenetics on campus at Stanford University.

The Deisseroth lab (d-lab) website also hosts

  • A light power vs distance attenuation calculator for brain tissue,
  • Chromophore, DNA sequence, and vector databases,
  • Information on requesting the many viruses and DNA provided by D-lab to other researchers.
  • Links to protocols for many optogenetics based methods.

Mapping Neural Circuits

Karl Deisseroth’s 2016 Cell paper serves as both a primer on mapping neural circuits via optogenetics and a review of the many optogenetic switches available for the task.

Finding the Best Switch

If you are hunting for the right optogenetic switch for your project, the OptoBase website provides curated databases of optogenetic techniques, but the true value is in the indexing, tagging, and online tools the BIOSS team created to accelerate your search. For example, In the publication search, filters such as “multichromatic” return only papers which combine multiple optogenetic switches within a single optogenetic system and “Exclude Background” let you exclude basic research on photoreceptors.

The OptoBase’s “Find the Application” tool is a publication selector allowing you to tick off  optogenetic uses (e.g. “Control of vesicular transport” AND “control of second messengers”) and returns only those publications which actually used those methods – as opposed to just mentioning them in the discussion section. Publications are tagged and updated weekly. The Optobase is a collaborative project of the BIOSS Centre for Biological Signalling Studies.

Preventing Phototoxicity during in-vitro Experiments

Phototoxicity presents the risk of introducing artifacts or cell death in both in-vitro and in-vivo experiments, particularly when the illumination wavelength is lower than 500 nm. For in-vitro experiments,  Káradóttir et. al. found that careful choice of the culture media components can prevent many of the issues from occurring in neuronal cell cultures. In particular, removing riboflavin, thyroxine, and triiodo-1-thyronine and including additional antioxidants increases cell survival considerably.

These media and supplements are now available from Cell Guidance.

Non-neuronal Optogenetics

For non-neuronal optogenetics, EMBL has placed a short introductory course online.

Transgenic Models – Ready to Go

While many companies supply strains of mice and rats ready for transgenic manipulation to introduce optogenetic switches, the Jackson Laboratory provide many strains of transgenic mice already expressing channelrhodopsin (CHR2), archaerhodopsin (Arch), and halorhodopsin (NpHR).

Turnkey In-Vitro and wireless In-Vivo Optogenetics Systems

Amuza provides Teleopto wireless systems for in-vivo optogenetics in mice and rats as well as LED arrays for in-vitro optogenetics in culture plates.

Teleopto wireless comprises a detachable, rechargeable headstage (receiver) and LED fiber optic implants which together weigh as little as 1.3 grams. Our starter kits are turnkey solutions for your first experiment, including receivers, LED implants, remote control, charger, and stereotaxic adapters.

Teleopto LED arrays are normally made for illuminating 96 well plates inside incubators, but can be customized to many different sizes and well configurations.

Both systems are available in colors across the spectrum including UV, violet, blue, yellow, green, red, far red, and IR. Multicolor options are also available. Please visit the Amuza site for more information:

Eicom USA is called Amuza Inc.

Eicom USA is called Amuza Inc.

Eicom USA has operated under Amuza Inc. since 2012,  it isn’t until recent that we decided to go by Amuza. The only change is in the name.

This allows us to provide you with more products that could have a great impact on your research. We are still providing and supporting Eicom products. As well as Amuza’s own brand of neuroscience products to complement those of Eicom. Including innovative microdialysis fraction collectors and rotating cage stages.

We are working hard to improve your experience and provide you with excellent support.

Please feel free to contact us at any time for your technical questions, price quotes, suggestions or complaints to our business. We love to hear from you.

The Amuza Team