Author Archives: Irene Jonathan

Does reduced microglial MyD88 signaling increase voluntary ethanol consumption and anxiety-like responses in a mouse model of binge drinking?

Irene Jonathan

Mentors: Julia Dziabis, Staci Bilbo, Ph.D.

Department of Psychology and Neuroscience

Microglia are immune cells of the brain and can be activated through toll-like receptors. When alcohol is consumed in excess, microglia produce inflammatory mediators. Zeroing in on the toll-like receptor adaptor molecule MyD88, our lab’s preliminary studies suggest that reduced microglial MyD88 signaling (dampening of inflammation) increases voluntary ethanol consumption. We hypothesized that the mice with altered microglial MyD88, Cre+, would drink more than the controls (Cre-) over a 6 week period. The Cre+ mice would be more anxious as well as having less cognitive flexibility compared to all other groups. To simulate chronic alcohol consumption, we utilized a drinking in the dark paradigm, where Cre+ and Cre- mice were exposed to alcohol 4 days a week for 6 weeks, and the amount consumed was tracked daily. Afterward, behavioral tests, such as Elevated Plus Maze, Light-Dark Box, and Barnes Maze were conducted when the animals were going through withdrawal. Our findings suggest that inhibiting the microglial MyD88-dependent pathway does not increase drinking in the Cre+ group compared to the controls, but overall females consumed more ethanol than males. Further exploration of the mechanisms underlying microglial inflammatory signaling and their relationship to excess alcohol consumption is an area of interest for future projects.

Lola’s Morning Glories

Although I missed one day of chalk talks, the ones I did see were super interesting and impressive. I particularly enjoyed Lola’s chalk talk about morning glories. It’s a field that’s incredibly different from my own and I think that’s why it caught my attention so much. 

Lola talked about a few points from her project and I learned a lot of new information during an 8 minute period. First of all, I had no idea what introgression was, so it was highly appreciated when she gave a quick definition. What I picked up is that in the wild introgression is rare, but it is a process that can occur in morning glories. Lola talked specifically about when there are pink and white flowers that are growing at the same place and time there are more white flowers. It was suggested that pink flowers aren’t good dads because their genes aren’t favorable to be fathers. Keeping all this in mind, she posed the question of if these offspring are recombinant, and that’s what she and her lab are testing right now. 

I thought it was cool to listen to Lola’s talk about her morning glories and it will be nice to hear what the answer to her research question is.

Mazes for Days

A day in the life of the Bilbo lab usually has some routine tasks that I do every day and then usually I learn a new lab procedure. For instance, in the morning I fill syringes full of ethanol for the drinking in the dark experiment (DID) we’ll do by 3 later in the day. Then I check on the mice’s water bottles, and every week I get to weigh them. After these things get done, I usually find Julia, my mentor, and I get to learn how to do a different protocol that she’s using for one of the projects she’s working on. For instance, over the past week, we’ve been running behavioral tests on the mice we’ve been working with for our DID experiment. The first test we did was an elevated plus-maze. This is a way to quantify the anxiety response in mice. The maze is in the shape of a cross, two arms have walls that enclose them and the other two are open. We put a mouse in the center then record what they do. The more time spent in the enclosed arms, the more anxious the mice are.

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Next, we did another test called the Barnes maze. This maze is a circular structure that has holes around the edges. One of the holes is an escape hole that the mouse goes into. We designate which hole we want that to be, then we place the mouse in the center of the circle and record how much time it takes them to find the hole. They then get to do this again 3 times. Now, this maze tests the mice’s memory because you conduct the test again the next day. Using the same escape hole, we use the same procedure, and hopefully, the mice remember where the hole was from yesterday. On the third day you switch it up, now the only thing you change is where the escape hole is. Typically, the mice go to the previous escape hole first because that’s what they remember and then it takes them some time to figure out where the new escape hole is. Since we have been running behavioral tests, the mice haven’t been drinking during their dark cycle, but usually, we give some of the mice ethanol and record how much they drink over 2 hours 3 days a week and 4 hours on Thursday. I’ve even gotten to run DID by myself. After recording the data in Julia’s lab notebook, I plug in the previous week’s data into excel and then plug the values into some statistical software that creates different graphs. 

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I like that on a day-to-day basis, I’ve settled into a routine with some of my tasks and I feel pretty confident about doing them by myself. But I also enjoy how almost every day, I’m learning how to do something new, and I feel like at the end of the program I will have gained a lot of new skills.

A Journey through Research

I was able to interview my PI, Dr. Staci Bilbo this week, and while I had met her once before. It was a great experience to learn about her career journey and why she chose to be a scientist in the first place. Dr. Bilbo studied psychology and biology at the University of Texas. The research she partook in focused on the spatial navigation of frogs and lizards and this is where she fell in love with research. It was a clear path for Dr. Bilbo to continue on to grad school because for her it was the best way to pursue a career in science. During her time at school, she became interested in the concept of neuroimmune interactions. It was a novel idea at the time to study the responses we have when we are sick and the idea that the immune system was playing a role in this. After taking a class on neuroimmunology, she learned about macrophages in the brain (microglia are one of them) and how behavioral changes must involve microglia in some way. This was an incredibly new concept because it was believed up until then that microglia only caused problems in the nervous system. Moving forward to the present, Dr. Bilbo runs her lab which focuses on microglia as well as having an appointment at Massachusetts General Hospital and running a lab and retaining employees there as well. 

Besides doing research, I asked Dr. Bilbo, what are other parts of her career she enjoys and she mentioned how much she loves teaching. It is an incredibly fulfilling part of her job at Duke and she gets to teach a neuroimmunology course that no one else does.  

Lastly, I wanted to touch on what she liked about science the least. She said how sometimes there is too much emphasis on how many papers you have published and how high an impact the journal it was published in is. This mindset discourages people from taking risks in their scientific endeavors because there is a chance that your experiment will not work and if that happens you can’t publish a paper. She wishes that there was more of an opportunity to simply conduct science for the joy of it because you do not know what will happen. You are at the forefront of emerging ideas and that is incredibly exciting even if they don’t work out. In summary, Dr. Bilbo wants scientists to have a better capacity for failing and I found this to be really encouraging advice. It’s really nice to hear your PI say that it is ok to fail and that it’s part of the process.

I had such a great time talking to Dr. Bilbo, and it was really cool to learn more about her. I’m super excited to keep working with her and my other mentors in the lab. 


Drinking in the Dark

The experiment I will be primarily working on uses a relatively common animal model called drinking in the dark or DID. We’re trying to see if there will be a genotypic difference between the amount drunk by the mice which could provide insight into the relationship between microglia and excessive alcohol consumption. 

This is a chronic experiment so this means we’re giving ethanol to mice during the dark cycle of the day for 6 weeks. The mice we’re working with are a transgenic line of myD88 mice. Myd88 is a 2 pronged pathway that downstream produces inflammatory cytokines. In our mice, we also use the cre-lox system. This allows us to selectively knock out one arm of the myD88 pathway only in microglia in some of the mice (cre positive) and the other mice are fine (cre negative). In some of our mice (the knockout ones), the amount of inflammatory cytokines is severely depressed but not completely eliminated since one arm of the pathway is still functioning. Preliminary data shows that female mice, in general, drink more. This isn’t necessarily surprising because from what I’ve learned sex differences are not uncommon when conducting microglial experiments. It will be interesting to see if this trend continues for the whole six weeks or if a significant genotypic difference will emerge as well when analyzing the rest of the data. 

Tipsy Tails In Lab

As a recently declared neuroscience major, my experience with the neuro department is pretty limited. While I’ve known for some time that all things concerning the brain are my primary interest, it’s always been over a pretty broad scope. Throughout this week, it’s been completely the opposite. I’m working in the Bilbo lab and it focuses on all things microglia. For those that don’t know microglia are the resident immune cells of the brain, but they do so much more. A lot of the research in the lab, in very simplistic terms, involves messing with microglia in some way and seeing the outcomes. That brings me to the experiment I’ve been helping with this week.

I’m working with mice and as someone who did not even grow up with pets, it was a bit of a shock the first day. But over two days, I’ve learned quite a few interesting things about them. Fun fact: mice can’t see red light, so whenever we work with them in the dark, we wear headlamps that shine red light. Speaking of the dark, a big part of the experiment is giving mice alcohol when the lights are off. I don’t exactly understand all of the scientific reasoning, but there is a really interesting relationship between alcohol (causes an inflammatory response) and microglia, so I’m excited to keep working on this project throughout the summer and to hopefully analyze some data.

Lastly, I wanted to talk about how working in research feels for the first time. As someone who was usually stressed during chemistry lab, I thought I would have a similar feeling when engaging in research. But I am happy to say that this has been an incredibly positive experience so far. Everyone I have interacted with in the lab has been super encouraging and responsive to the questions I have. I already feel like I’ve learned a lot, not only about microglia but how to be a better scientist so I’m looking forward to how much I know by the end of this program.