Tag Archives: UGSRF

Investigating the role of the androgen receptor in polycystic ovarian syndrome

Research Project

For the past summer, I have been working in laboratory of Dr. Sheng UW at the Johns Hopkins School of Medicine. In the Wu lab, we are investigating the etiology of polycystic ovarian syndrome or disease (PCOS/PCOD). One of the major clinical presentations of PCOS is high levels of androgens, a condition known as hyperandrogenism, and the Wu lab focuses on the androgen receptor (AR) which binds to androgen outside of cells and acts inside the cell to express certain genes. The mouse model that we use mimics hyperandrogenism by exposure to dihydrotestosterone (DHT), which is present in low amounts in women without PCOS. To investigate mechanisms of hyperandrogenism and the AR, knockout mice without the receptor are compared to control mice, enabling us to investigate the effects of differential levels of DHT and the role of the AR on fertility, gene expression, protein and RNA levels, adipose tissue, and ovarian morphology (Wu et al., 2014). Despite the prevalence of PCOS in women of reproductive age, and its association with metabolic dysfunction, infertility and hirsutism, the exact cause is not known and effective treatment options are not available. By elucidating the pathophysiology of PCOS, treatment can be designed to target the cause as opposed to only clinically managing the symptoms temporarily.

Realities of Research

Although the prospect of doing research in a lab might sound like it involves the use of expensive equipment and the newest technology (and in many cases this is very true), a large portion of research involves spending hours maintaining and genotyping new litters, waiting for assays and reactions to finish, and pipetting hundreds of samples. Experiments sometimes work, and at other times they fail and must be repeated. Small errors in pipetting or mindlessly forgetting to include a certain solution can cause time-consuming experiments to fail. But, the most critical learning experiences I have had thus far were assessing what went wrong and fixing it by. Results are also not immediate; it takes several weeks before the effects of DHT can be assessed. Confirming the genotypes of our mice is critical to make sure that we are investigating what we claim to be, and ensuring DHT surgeries are done at the correct time requires attention and organization. Preliminarily, the effects of DHT we have observed have been physiologically plausible, although much of the data collection of the study is still ongoing.

Life of a Scientist

Simultaneously, the best and worst parts about doing research in a lab are that the hours are flexible and I can plan my week. But, this also means spending evenings working due to long wait times for experiments that extend past the usual 9 to 5 working day, or because a protocol calls for a certain experiment to be done at a certain time. The independence is exciting, but can also be intimidating as I must be aware of what needs to be done and when. However, research is collaborative. As the youngest and most inexperienced person in my lab, I am always learning how to do new experiments and how to interpret and analyze data. Others are always offering me tips and tricks, supporting me when I fail, and helping me deal with my constant fear of getting bitten by mice. The most rewarding moments of the summer so far have been presenting data to my PI and co-PI, and teaching members of the lab how to complete a computerized tissue analysis that had not been done in our lab before. The most disappointing? Waking up early to complete a western blot protein analysis only for it to fail – not once, but multiple times!

References:

  1. Wu, S., Chen, Y., Fajobi, T., DiVall, S., Chang, C., Yeh, S. and Wolfe, A. (2014). Conditional Knockout of the Androgen Receptor in Gonadotropes Reveals Crucial Roles for Androgen in Gonadotropin Synthesis and Surge in Female Mice. Molecular Endocrinology, 28(10), pp.1670-1681.
Gopika Punchhi is a rising senior at Johns Hopkins University in Baltimore, MD, pursuing degrees in Molecular and Cellular Biology and Public Health Studies. Through the Undergraduate Summer Research Fellowship (UGSRF) program, she is spending the summer working under Sheng Wu, PhD, an associate professor in the department of Physiology at the Johns Hopkins School of Medicine. UGSRF is funded by the APS. Gopika plans on attending medical school to become and gynecologist or endocrinologist, while also continuing involvement in molecular and population-level research in these fields.
Stem Cell Summer Research

Research Project

Throughout our lives we accumulate damage naturally in our day-to-day activities. Thankfully, our bodies have an incredible potential for repair. Damaged tissues might follow a sunny day at the beach without sunscreen or the micro-tears in muscles resulting from a hard workout, are repaired by our bodies via the orchestration of numerous cellular processes. In response to tissue damage, various proteins will signal to specific cells in the damaged tissue that have the potential to differentiate and repopulate damaged tissue, inducing a regenerative response. These specific cells are known as stem cells .

My research this summer focused on a protein complex that has reported roles during aging and in mediating repair in particular tissues: mTORC1. In muscle, mTORC1 has been shown to be crucial to the activation of muscle stem cells, which are normally dormant, so that they may repopulate the damaged muscle by replacing injured cells with new, healthy cells. Although the role of mTORC1 in tissue regeneration is well understood in muscle, its role during repair is unclear within many other organs, particularly the intestine. The inner lining of the intestine, known as the intestinal epithelium, experiences tremendous damage on a daily basis, in part, as a result of the mechanical stress to the intestinal cells from the passage of food. As such, the intestinal epithelium is one of the most proliferative tissues in the human body, having the capacity to turnover every 5-7 days. My research this summer aimed to understand the role mTORC1 in repairing the intestinal epithelium after injury, and also to understand how this role may differ from its activity in an uninjured context, during homeostasis. We hope that the results from this work will help us better understand the intestinal regenerative process in order to someday have the capability to pharmacologically enhance regeneration in injured individuals, or prevent it, in conditions such as cancer where tissue grows excessively quickly.

Realities of Research

One of the aims of my research project was to focus on the role of mTORC1 during homeostasis. I hypothesized that if the activity of mTORC1 was inhibited, stem cell activity in the intestinal epithelium would be impaired. After genetically manipulating mice so that mTORC1 activity was only depleted in the intestine, we saw that mice lost a dramatic amount of weight and became sickly. We also expected a change on the cellular level. For instance, we anticipated changes in the number of cells actively dividing in the intestinal epithelium as well as changes in the architecture of intestinal epithelial cells. In order to better visualize the number of cells actively proliferating within the intestinal epithelium, I used a cell staining technique called Edu staining which allowed me to visualize each cell undergoing division. Once imaged, I could then quantify the exact number of cells undergoing division within a set amount of time and compare the number of proliferating cells in mice in which mTORC1 was depleted, compared to control mice with normal mTORC1 activity . The Edu staining showed a decrease in the number of cells proliferating in mice depleted of mTORC1 activity, further supporting my hypothesis. In order to further characterize the changes that occur after obstruction of mTORC1 activity, I plan to determine whether intestinal stem cell number is affected following genetic mTORC1 depletion. I also plan to analyze the general structure of the epithelial tissue using a staining technique called H&E staining and quantify the number of cells undergoing programed cell death using cleaved caspase 3 staining.

Life of a Scientist

This past summer, I’ve learned a lot about what it means to do research. Primarily, I’ve discovered the necessity of having keen attention to detail. Prior to working in Dr. Samuelson’s lab, I hadn’t realized how many steps need to go correctly in order to obtain data from an experiment. For instance, to complete a Western Blot, which is an experimental technique used to separate and identify a specific protein from a sample containing hundreds or even thousands of proteins, each step in the process must be executed with acute accuracy and precision. First, the mice had to be treated with the proper experimental treatment. Following the harvesting of the tissue, the protein within had to be extracted and quantified extremely accurately. Finally, the Western Blot could be run, which also has potential for error. If even a single step within the entire time intensive process was completed inaccurately or improperly, the Western Blot likely wouldn’t work and the entire process would need to be redone.

As I near the end of my summer in Dr. Samuelson’s lab, one of my biggest takeaways from working in the lab is that a scientist is never done learning. Sitting in on lab meetings with a team of experienced scientists and PhD students has shown me that even experts in certain fields don’t have the answers to every question. During my ten weeks in the lab, each week was entirely different. While there were several core skills that I learned and expanded upon through practice throughout the whole summer, each week also came with new scientific techniques and new ways of thinking and approaching problems. This constant exposure to new information and lifelong learning is what excites me as a scientist.

Yasmine Abushukur is a senior at the University of Michigan studying both French and Bimolecular Science. This summer, she worked in Dr. Linda Samuelson’s lab thanks to funding from the APS Undergraduate Summer Research Fellowship. This upcoming school year, she plans to continue working under Dr. Samuelson’s guidance, studying gastrointestinal physiology. After graduation, she plans pursue a career as a physician-researcher.
Multisensory Control of Blood Pressure

When we go from a lying down position to standing up, our blood tends to pool in our legs and has to fight against the force of gravity to travel our brain. Overcoming the force of gravity is the greatest challenge the cardiovascular system faces. Luckily for us, our body is able to detect when such changes are to occur and can effectively change blood pressure to compensate for the change in posture. The body has many different sensory inputs that contribute to homeostatic regulation of blood pressure during these postural changes. The vestibular system, baroreceptors, chemoreceptors, and higher order brain centers (hypothalamus and cerebral cortex) are all examples of the body’s many sensory inputs (Yates et al. 2014). If these homeostatic responses perform inadequately, then conditions such as orthostatic hypotension can be the result (Yates et al. 2017). Orthostatic hypotension results from a drop in blood pressure due to a change in posture, where insufficient perfusion of blood with the brain occurs. My research project this summer focused on the cardiovascular responses that are necessary to maintain normal biological homeostasis during anticipated imposed postural changes. Homeostasis is defined as the tendency of biological systems to maintain relatively constant conditions in the internal environment while continuously interacting with and adjusting to change originating within or outside of the system (The Free Dictionary, n.d.).

In this study, my lab investigated the activity of neurons in the RVLM (rostral ventrolateral medulla), located in the brainstem, in awake adult female cats. There has been significant research to support the claim that neurons in the RVLM play in important role in blood pressure regulation in both animals and humans (Yates et al. 2017). RVLM neurons are necessary for cardiovascular responses to maintain homeostasis during postural movements. The neurons in the RVLM were identified by their changes in firing rate correlated with the cardiac cycle and their location. The experiments in the lab involved recording the activity of neurons in the RVLM during imposed 40º head-up tilts that were preceded by a light cue. The light cue occurred 10 seconds before the 40º tilt, and the heart rate and firing rate of neurons were determined for 5 second time periods before and during the tilts.

Our hypothesis is that in neurons that exemplify cardiac related activity there is an increase in neuronal activity prior to the onset of the 40º imposed tilt, in the time interval after the light stimulus as compared to before the light. This would indicate that when the animal is able to anticipate when the change in posture is about to occur, the animal’s cardiovascular response system will increase heart rate and blood pressure to prepare for the postural change. This would be an example of a feedforward mechanism rather than a feedback. In a feedback mechanism, the animal would have already undergone the change in posture and body positon in space before the cardiovascular response system could compensate heart rate and blood pressure.  This research project will ultimately further our knowledge of cardiovascular homeostasis and may lead to new treatment options for orthostatic hypotension and also a treatment for cognitive mechanisms that can cause changes in blood pressure such as stress and anxiety.

Figure 1: An example of the data that was collected and analyzed during one of the tilt table experiments. The x-axis shows the change in time as the table went from a nose down position, to a 40º head-up tilt. The neuronal firing was isolated along with the heart rate through the use of an EKG. The sun cartoon indicates when the light stimulus was shown with the five second time intervals appropriately labeled before and during the head-up tilt. Credit: Dr. Bill Yates’ Lab, UPMC Department of Otolaryngology.

 

Realities of Research

I was extremely grateful to take part in this research opportunity this summer as it really allowed me to grow as an undergraduate researcher. The reality of research is that you get out of it what you put in. If you’re motivated and passionate about what you are doing, then I believe that anyone will be satisfied with the outcome of their experience. I became enamored with learning about physiology after completing Dr. Yates Honors Human Physiology class. After completing his course, I was eager to investigate what research was like on the physiological spectrum. Over a course of 10 weeks, I completed dozens of experiments and analyzed large amounts of data. We performed single-unit in vivo recordings using electrophysiological techniques and procedures. When experiments ran to completion and a respectable amount of usable data was collected, the day was considered successful. Another reality of research is that not every experiment is going to go as planned. There were experiments where either the animal wasn’t cooperating on the table, an electrode bent, or we just simply couldn’t isolate any good neurons to record from. When problems like these would occur, we would simply end the experiment and try again the next day. Because there are a great deal of experiments left to perform and more data analysis to complete, there are no final results or conclusions yet to be made. However, we do predict that the firing rate of the cardiac-related neurons will increase after the light stimulus is given, prior to the onset of the tilt.

Figure 2: The tilt table that is used in all of the single-unit in vivo recordings. During an actual experiment, the curtains would be drawn and the lights would be dimmed to allow for the light stimulus to appropriately work. The machines in the back are used to find and isolate a neuron in the RVLM and to change the position of the table. Credit: Dr. Bill Yates’ Lab, UPMC Department of Otolaryngology.

 

Life of a Scientist

I sincerely enjoyed my daily routine as a scientist in the Yates lab. I was able to set my own schedule and I developed meaningful friendships with everyone I worked with. It was a very-low stress working environment and most days I would follow the same routine. A huge part of my project this year was analyzing the data collected from the experiments. When I wasn’t running any experiments I would be on the computer analyzing large amounts of data. Analyzing data is something that a lot of undergraduate students have trouble with, mostly because it takes a lot of time to learn and pick up. I was very surprised by how quickly I was able to pick up the skill and it allowed the lab to make huge amounts of progress throughout the summer. My fondest memory of my time in the lab didn’t actually happen in the lab. On a Friday afternoon after work, everyone in the lab went out to a Pirates game at PNC Park in Pittsburgh. It was my first one and it was really fun to see everyone outside of the lab doing something together. Overall, I had a great summer and I’m very thankful that APS gave me the opportunity to see what full-time research was actually like. This summer experience was very rewarding and has motivated me to pursue my continued interest in biomedical research.

 

References

  1. Yates, B. J., P. S. Bolton, and V. G. Macefield. 2014. Vestibulo‐sympathetic responses. Compr. Physiol. 4:851–887.
  2. Patel, N.M., Baker, E.A.G., Wittman, S.R., Engstrom, I.C., Bourdages, G.H., McCall, A.A., Miller, D.M. and Yates, B.J. Cardiovascular adjustments during anticipated postural changes. Physiol. Rep. 6(1), e13554, 2018
  3. TheFreeDictionary.com. (2018). Homeostasis (Biology). [online] Available at: https://medical-dictionary.thefreedictionary.com/Homeostasis+(Biology)
John Bielanin is a rising senior majoring in Neuroscience and minoring in Chemistry, with a certificate in Conceptual Foundations of Medicine at the University of Pittsburgh in Pittsburgh, PA. He is a 2018 Undergraduate Summer Research Fellow working in Dr. Bill Yates’ lab in UPMC’s Department of Otolaryngology at the University of Pittsburgh. John’s Undergraduate Summer Research Fellowship (UGSRF) is funded by the American Physiological Society. Outside of school and work, John enjoys reading, writing music, and spending time outdoors. After graduation, John plans on applying to medical school while continuing to pursue research opportunities in his gap year.
My Summer of Scientific Research

Over the summer I have been working at Emory University with Dr. Tansey and other lab members looking for potential causes of Parkinson’s disease (PD). Parkinson’s disease is an illness that damages important parts of the brain and nervous system. This can cause a loss in efficient body movement. We believe that a specific protein, something that the body naturally makes, called LRRK2 may play a role in this disease because there is an increased amount found in PD patients compared to healthy controls. Therefore, we have studied this protein by trying to pin point its location in the body and learning how it causes other PD symptoms such as inflammation. This research will not only provide answers for PD, but can be used to learn more about other neurodegenerative diseases. The goal is to one day cure such debilitating illnesses for everyone who is unfortunate to develop them.

Realities of Research

One of the biggest things I have learned about working in a lab is that your plan of action can suddenly change, while the goal stays the same. However, there are many times where you must go back to the “drawing board” and erase or insert something new. To me, going back and finding out that you have to try something new is a good thing. You are improving on your research and hopefully it will bring you closer to significant results. I also had other learning opportunities such as improving on specific lab techniques. During my BCA assay (Bicinchoninic Acid assay), which is a protocol used to standardize amounts of proteins in a sample, I had to perfect my pipetting skills for the assay to work. I practiced for hours to get the exact amount of solution every time I withdrew from a tube before I actually ran the real assay. This summer, my project started off bumpy because of an experiment not going as planned. I was taking tissue sections of kidney to stain and investigate for the colocalization of LRRK2 with the primary regulator NFAT (Nuclear Factor of Activated T-cells) and pNFAT (NFAT promoter) status in the nucleus. We were looking at these specific cells because they are involved with the immune system which LRRK2 seems to help regulate. However, after my staining protocol, the kidney cells would essentially combust. After many days of trial and error, we decided that there was not enough knowledge of kidney staining in our lab, and instead of spending time and resources to figure it out we moved on and started looking at a new location. There were plenty of times where we had to re-evaluate our plan, and as I said before I only see them as learning opportunities. Sometimes research is not always going to be straight forward where you make a hypothesis, go through an experiment, and at the end collect an answer. It can take a lot of time and creative thinking to get where you need to go.

Damaged kidney cells.

Life of a Scientist

Being a part of a lab is great for many reasons. One reason is that I prefer the type of work style that it offers. Those aspects include being able to have flexibility within your schedule and not having to be constantly micromanaged. Yet, I am still offered enough guidance to steer me on the right track. I love that every day is another day pushing towards a goal that you most likely had a hand in setting. I am also surrounded by people who all want to see each other succeed. Although everyone in the lab may be working on their own personal agendas, people are constantly helping others with their projects whether it’s by lending their skills for a certain assay or giving an extra hand to make timely experiments go by faster. I would go on to say that the entire science community within your field begins to feel more familiar as your work progresses, as well. I value this idea of a connected community within my workspace. Overall, my experiences in my lab this summer were positive and resourceful. Of course, I have witnessed complications occurring in the lab such as assays not going as planned or having to re-due them because of minor mistakes. Human error constantly occurs and I have learned that you can only work with it and make sure to try as hard as possible to get accurate, significant results. Knowing that I could make a career into doing what I love, conducting science and answering important questions that benefit humanity, gives me the motivation of becoming a neurologist in the future.

Chayla Vazquez is a rising junior at Emory University in Atlanta, GA where she is majoring in Neuroscience and Behavioral Biology, with a minor in Ethics. She is working at Emory over the summer with Dr. Malu Tansey as an Undergraduate Summer Research Fellow (UGSRF) funded by the American Physiological Society. Chayla strives to become a biomedical scientist and utilize her skills in research to help people who struggle with cognitive defects.
Regulation of Salinity Stress Tolerance in the European Green Crab, Carcinus maenas

Throughout the summer of 2017, I worked in the invertebrate physiology lab under Markus Frederich, investigating how the enzyme AMPK affects the salinity stress tolerance of European green crabs. Using crabs collected from the Maine intertidal areas, which often experience variances in salinity and temperature, I focused on injecting and activating this enzyme. By doing so in settings of different salinities or temperatures I was able to see how the enzyme plays a role in ion regulation and stress tolerance, giving insight into what makes this species such  successful invaders.

Participating in this research experience has been extremely valuable. I have been able to acquire lab skills which are imperative to my future as a scientist, while also receiving a unique opportunity to develop a very strong understanding of a very specific topic that is very exciting. Coming into my summer research experience, I felt nervous and overwhelmed thinking that I had so much to learn in so little time, but very quickly I got into a comfortable position of diligent work, where I learn something new every day. Scientific research involves patience, and while everything might go right the first time, I have learned that it may not be because of a mistake, but that a different approach needs to be taken.

Being a scientist is a surreal experience because it is such a meticulous practice. The smallest things can cause large alterations in data, and knowing that makes me appreciate the practices of scientific research that much more. Every day involves thinking outside the box, and a true dedication of time. The best part is learning something new every day, and while it may be exhausting to sometimes go multiple days with nothing making sense or things not working, there comes a moment where something new is discovered, which is extremely rewarding. I am truly appreciative of the lab that I work in because everyone is willing to help each other, working together to answer questions, and learn from one another. My advisor specifically has been very influential in making this summer experience one of the best things I have ever done, and has been a strong influence for my love for research.

 

Pierce Lancor attends the University of New England in Biddeford, ME. She is a 2017 Undergraduate Summer Research Fellow (UGSRF) and worked in Dr. Markus Frederich’s lab over the summer at the University of New England. After graduating, she plans to continue her education and research toward a masters and PhD in zoology.
Kidney Gene Per1 Regulation of Blood Pressure

This summer I had the great opportunity to work as a fellow within the American Physiology Societies Summer Undergraduate Research Fellowship program. I was able to study under Dr. Michelle Gumz who focuses on circadian rhythms in the kidney at the University of Florida. Circadian rhythms help us wake up and brush our teeth in the morning and fall asleep the same time every evening. Four distinct classes of genes called Per, Cry, Bmal, and Clock, regulate these rhythms. Our lab studies the regulation of Per1 and its effects on blood pressure as a circadian rhythm. Mean arterial blood pressure decreases at night when humans sleep, called “dipping” and peeks when we first wake in the morning (Solocinski, et al., 2016). My research project is designed to study the effects of removing the Per1 gene globally from the 129/sv/s1s4 mice background. After the mice are developed we inserted a radio-telemetry device to monitor their hourly blood pressure. With that data we run specific statically analysis, including cosinor analysis. Cosinor analysis is a program to studies the mesor, amplitude, period, and acrophase of the mean arterial pressure (MAP) of each animal. The mesor, midline-estimating statistic of rhythm, is the midpoint on the y-axis and based on the distribution of MAP across the circadian rhythm. The amplitude is the distance between the mesor and the maximum/minimum point of oscillation. The period is the measure of a full circadian wave. The acrophase is the distance along the cycles peaks or crests that fits the measurement of the circadian rhythm. Each variable allows us to observe the MAP in a circadian pattern to determine the variation between WT and KO 129/sv/s1s4 mice. After I complete the analysis of the blood pressure data from the 129/sv/s1s4 mice we will then run western blot and immunohistochemistry analysis to observe the different proteins within the kidney.

Working in a biochemistry research lab everything is measured in micro values and we work with small portions of protein and DNA to test for specific genes. The process of discovering new proteins expressed in wild type or knockout kidneys is an exciting experience. We develop new conditions for western blots, which is a detection process for select proteins within a sample by using antibodies. Each antibody needs individual concentrations and washing methods to discover the correct ratio to produce a viable band of protein. In addition to study the changes within different proteins levels it is also important to observe the physiological response within the animal models. Measuring hourly blood pressure points allows us as researchers to recognize how the animal is adjusting towards the global removal of the Per1 gene. Once we understand the physiological response and how the body adapts to gene changes we can then apply this result to human studies. Blood pressure regulation is a major contributor to heart disease. If we are able to better comprehend the circadian clock gene regulation within the kidney we could improve cardiovascular outcome.

Our procedures for western blots and immunohistochemistry can take two to three days to see results. It can be concerning when we do not produce correct results, but as a lab we make adjustments and start the protocol over again. Through the optimizing process it can take weeks to produce a blot with results from our Per1 knockout mice population. However, once we optimize the antibodies we can test multiple samples to gain data for publication. Working alongside Dr. Gumz and her PhD students, it creates a reliable environment for undergraduate students learning basic scientific procedures. Working with a team allows me to make mistakes and learn how to correct different procedures to perfect western blot, immunohistochemistry, and telemetry protocols. The life of a scientist can be very rewarding when you are able to optimize protocols and receive results that can determine different gene regulations. Within the Nephrology Department at the University of Florida we attend weekly meetings to discuss other research from a variety of department labs. This allows me to learn about different lab protocols and apply their procedures to our current studies to produce ideal results. This summer research fellowship was a wonderful opportunity for me to improve as an undergraduate researcher and make connections with students across the country that are also interested in pursuing science.

References

  1. Solocinski, K., Holzworth, M., Wen, X., Cheng, K., Lynch, I. J., Cain, B. D., . . .Gumz, M. L. (2016). Desoxycorticosterone pivalate-salt treatment leads to non-dipping hypertension in Per1 knockout mice. Acta Physiologica,220(1), 72-82. doi:10.1111/apha.12804
Amber Miller is a rising senior majoring in Health Science at the University of Florida in Gainesville, Fl. She is a 2017 student in the Undergraduate Summer Research Fellowship that is funded by the APS. Amber works in Dr. Michelle Gumz’s lab at the University of Florida that focuses on circadian genes and its effects on blood pressure. She is currently applying to medical school this summer with plans to become an academic physician in the field of physiology.
Getting Salty About Hypertension

About 30% of the world’s population has hypertension due to a recent surge of salt in our diets (1). According to the American Heart Association, the average American eats more than 3,400 milligrams of sodium daily, while the ideal limit is 1,500 mg per day for most adults (2). So, how does your body know when you have ingested salt? Your brain has specialized cells that monitor the amount of sodium (and other ions or substances). Some of these cells are located in the Organum Ventral Lamina Terminus (OVLT). OVLT is one of a few special section of the brain that lacks a complete blood brain barrier that allows substances in the blood to pass more freely from the bloodstream to the brain. So, this section of the brain essentially has the equivalent of “x-ray vision”; it can “see” the particles in the blood, such as salt, and send messages throughout the body to initiate responses. One of these responses may be to increase blood pressure, which is known as salt-sensitive hypertension. Salt-sensitive hypertension refers to an increase in arterial blood pressure to an increase of salt intake.

 

Figure 1. Rat diagram with optogenetic set-up.

My project utilized a new innovative tool known as optogenetics to inhibit or “turn off” OVLT neurons during dehydration and acute NaCl loads. Optogenetics works by shining a light at different wavelengths at a region of the brain where a light activated or inhibited ion channel was injected via a virally-mediated delivery system. In my experiments, water intake, urine output, and blood pressure (via telemetry) were measured in rats dehydrated overnight or infused with a concentrated NaCl solution with or without the laser on to inhibit OVLT neurons. I found that when these neurons were inhibited, they would decrease the volume of water intake of the rats. Upon further investigation, if OVLT continues to prove to be a major contributor to salt-sensitive hypertension, we hope more methods will be developed and implemented in humans suffering from this disease.

 

Figure 2. Leica Vibratome used to take serial sections of brain to determine injection location. Credit: Dr. Sean D. Stocker’s Lab, University of Pittsburgh Medical Center

Research is a very rewarding occupation. Although experiments can be long and time sensitive, the outcome is worthwhile. As long as you are careful and perform experiments honestly, any result can be used to learn. Further, I was amazed by the techniques I used to complete my experiments. The science and technology behind them is very interesting and innovative. The use of optogenitics is relatively new and entails complex surgeries and sciences. Unfortunately, with complexity comes consequences, and I have hit some bumps in the road. The technology used on the rats was very fragile and could not be fixed if broken. In addition, since it is not possible to alter salt concentrations without altering other aspects of the rat, we had to test the secondary stimuli to see what affect they had on the rats’ behavior. I am not finished collected data yet for this summer, but the results appear promising. In addition, I still need to test more animals and determine if the injected virus hit OVLT in order to define my conclusions.

 

Upon arriving, I was most surprised by the dynamic of the lab. All lab members are working on separate projects, but with related goals. Work is mostly independent, yet the goal is interdependent.  Working with a lab team was a fulfilling experience and helped me gain a better understanding of my project. I was able to learn new things and make better sense of my project through communicating with my team members. The best part of my research is the technology and innovation associated with it. One of my favorites is the way we analyzed water intake by applying basic principles of circuits. During experiments, the rats are in cages with metal floor, plastic walls, and water bottles with metal spouts. A wire connected the floor to the spout of the water bottle, creating an incomplete circuit. When the rat takes a drink, it completes the circuit because it is touching both the metal spout and floor. This causes a voltage to occur, which is recorded on a computer application. This data is used to determine when the rats were drinking, and it can approximate water intake because duration of time at the water bottle spout correlates with the amount of water the rats ingested. In contrary, the worst part of my research was the delicacy of the animals. It is very disheartening when the head caps fall off the rats and no longer can be used for experiments. Another incommodious aspect was the time sensitivity of experiments. I have to give the rats time between experiments, so some days were much slower than others. All in all, the positive aspects of research have outweighed the negative, thus far. It has further peaked my interest in a future of biomedical research, and I would recommend anyone interested in the sciences with a love of problem solving to engage in research!

References

  1. Choi HY, Park HC, Ha SK. Salt Sensitivity and Hypertension: A Paradigm Shift from Kidney Malfunction to Vascular Endothelial Dysfunction. Electrolytes & Blood Pressure 13:7-16, 2015 [14 July 2017].
  2. How Much Sodium Should I Eat Per Day? [Online]. American Heart Association. https://sodiumbreakup.heart.org/how_much_sodium_should_i_eat?utm_source=SRI&utm_medium=HeartOrg&utm_term=Website&utm_content=SodiumAndSalt&utm_campaign=SodiumBreakup [14 July 2017].
Rachel Maile is a junior majoring in Biological Systems Engineering and minoring in Biomedical Engineering at Virginia Polytechnic Institute and State University (Virginia Tech) in Blacksburg, VA. She is a 2017 Undergraduate Summer Research Fellow (UGSRF) working in Dr. Sean D. Stocker’s lab at the University of Pittsburgh Medical Center in Pittsburgh, PA. Rachel’s fellowship is funded by the APS and has enabled her to further her appreciation for research. After graduate, Rachel plans to perform biomedical research, using her engineering background and physiological expertise.
A Summer of Fibrosis

This summer I have had the unique opportunity to work on a project that involves human heart tissue, an opportunity provided to me by the American Physiological Society and the Campbell Muscle Lab at The University of Kentucky.  My project focused on heart failure, a topic that is vital to many Americans, in fact, the American Heart Association showed that approximately 5.7 million adults in the United States suffer from heart failure. My study looked specifically at the varying amounts of collagen based on sex and heart failure status. It has been researched and shown that there is an increase in fibrosis when a patient has heart failure. Fibrosis is a term that describes tough fibers that replace damaged cardiac tissue in a process known as cardiac remodeling; an example of fibrosis is collagen, the protein that we stained for. The unique part to this study is the comparison of men and women, regarding the amount of collagen present in the heart tissue. This idea stems from a previous experiment conducted in the lab that used a process called Nanostring to determine the expression of genes related to heart disease and failure in both failing and non-failing human hearts. This study showed that there were genes related to collagen that had sex specific differences. Although the experiment might not be revolutionary, it will aid in bridging the gap that currently exists in research regarding the physiological difference between men and women. Although, we do not have enough data to draw conclusions yet, we are already thinking about future directions for our project!

The Realities of Research

Research is an imperfect process to say the least, and in my opinion that is what makes it wonderful. Things do not always go as anticipated when conducting research. It might not always yield the expected results, but it was at the very least a learning experience. One of the largest realities I had to face was that just because a protocol is well established does not mean that it is easy to learn, or unalterable. The protocol for my experiment is one that is well established and has been for many years. That would ideally make the project simple, right? Wrong. At the beginning, there were numerous problems, most associated with a steep learning curve. Part of my job is to cut tissue, and there were many rat heart samples that had to be cut before I could begin working with human tissue. Once the cutting was mastered, there was still a problem with the staining aspect of the protocol.  The protocol written seemed clear, but the results of the stains were not up to par. So, we worked to adjust the protocol in order to obtain samples that were suitable enough to analyze. This steep learning curve was rough, but it made for a great application of problem solving skills.

The Daily Life of a Scientist

The daily life of a scientist is quite interesting, especially in my lab. Sometimes the day to day life of a scientist can be a little monotonous. I would come in and cut the tissue, stain the tissue, and image the samples, but just when things were getting a little boring, we would get a call on what we call the bat phone. The bat phone rings whenever there is a heart transplant or an organ donor, who is unable to donate his or her heart. We are then able to take the heart and store it for future research for our lab or any other that wants to use human samples. We are on call 24/7 and there are times where I must leave an experiment to collect a heart. Although this seemed inconvenient at times, such as 2 AM, it was great to have such a unique opportunity. The daily life of a scientist in the Campbell Muscle Lab is exciting, challenging, and unique to say the least.

References

  1. Mozaffarian, Benjamin, Go, Arnett, Blaha, Cushman, . . . Turner. (2016). Heart Disease and Stroke Statistics—2016 Update: A Report From the American Heart Association. Circulation, 133(4), E38-E360.
Autumn Conger attends the University of Kentucky in Lexington, KY. She is a 2017 Undergraduate Summer Research Fellow (UGSRF) and worked in Dr. Kenneth Campbell’s lab at the University of Kentucky. Autumn plans to go to medical school and become a physician scientist. She hopes to help in bridging the gap between the fields of medicine and research.
Stemming Beyond the Brain

This summer, I am very thankful to be a recipient of the Undergraduate Summer Research Fellowship (UGSRF). This fellowship has given me the opportunity to conduct research under the guidance of Dr. Justin Grobe at the University of Iowa. My research project studies the role of AT1a receptors on the vasopressin-producing cells found in the hypothalamus region of the brain.

Vasopressin (AVP) is a hormone, produced in the magnocellular neurons within the hypothalamus, playing a key role in maintaining homeostasis. This hormone maintains homeostasis by increasing blood pressure through upregulation of water reabsorption and vasoconstriction. The AT1a receptor responds to high levels of angiotensin II, ANGII, by constricting the cells with AT1a as part of the renin-angiotensin-aldosterone system, RAAS. A previous study conducted in our lab has shown AT1a receptor localization on vasopressin-producing cells in the supraoptic nucleus of the hypothalamus1. In order to observe the role of AT1a receptors, the experiment compared the response of AT1aAVP-KO mice with control mice under the ICV infusion of ANGII or aCSF at 50ng/hr. Specifically, I am looking for responses in water-intake, urine output, blood pressure, and vasopressin secretion. This experiment will provide further insights to understand AVP secretion in response to brain RAAS and could potentially help prevent hypertension, exhibited patients with obesity, diabetes, and/or preeclampsia.

Figure 1: qPCR machine for gene expression analysis

I have learned many valuable skills from conducting research over the course of this summer thanks to my awesome mentors and principal investigator. They have devoted their time to teach me how to use Excel in analyzing the results of specific qPCR gene expressions and creating protocols for many experiments utilized in the lab. Nevertheless, there are many other essential skills that I have yet to learn such as interpreting results, reading scientific journals, and other lab protocols. They are important in all aspects of research but honing in these skills will require time and practice. For instance, several experiments that I performed yielded poor results and required additional extra time devoted towards troubleshooting the problem. Although frustrating at times, I have learned troubleshooting is one of the most important skills in research because not all the experiments will yield the desired results. While learning and refining my skills, the research project has progressed into the final stages towards completion and I am very excited to find out what results from the samples reveal regarding the role of AT1A receptors.

Figure 2: Tail-cuff system setup for blood pressure measurement

As a member of the lab during this summer, I have gained an insight into becoming a scientist. Every morning is devoted towards measuring the blood pressure in the mice cohorts, which need the measurements to be taken daily for three weeks prior to the surgery and two weeks after. The afternoon is spent performing qPCRs on specific genes from tissues collected earlier, analyzing data, learning new protocols, and/or reading publications pertaining to my research area. There are many basic aspects that scientists value greatly such as labeling tubes, checking the timer, and pipetting the exact amount of solutions. The focus on minute details is a trait developed over the years dedicated towards conducting research, and I have definitely noticed improvements in my attention to detail since I first began conducting research. In the next couple of weeks, I will have the opportunity to collect, organize, and analyze the results during the finals days of this experiment. I would like to again thank APS for the opportunity to conduct research at the University of Iowa this summer.

References

  1. Linggonegoro D, Sandgren J, Claflin K, Perschbacher K, Ni J, Pearson N, Pierce G, Santillan M, Grobe J. Physiological Significance of Angiotensin AT1A Receptors in Vasopressin-Producing Cells of the Supraoptic Nucleus. Experimental Biology.
  2. Guyton AC, Hall JETextbook of Medical Physiology. 10th ed. Philadelphia, PA: W.B. Saunders Company, 2010.
I am rising junior at the University of Iowa, majoring in biomedical engineering. I will be pursuing a biomechanics and biomaterials track with an interest in implant design and drug delivery. This summer, I had the opportunity to conduct research under my principal investigator, Dr. Justin Grobe, with the assistance of UGSRF fellowship funding by the American Physiological Society. My project investigated the role of AT1a receptors on the vasopressin-producing cell in cardiometabolic control.
Investigating the Role of Piezo2 in Serotonin Release

At the mention of serotonin, people commonly think of its role as regulating anxiety, mood, and happiness in the brain. However, 95% of the body’s serotonin is produced by enterochromaffin (EC) cells present in the tissue lining of the gut (1) before being taken up by platelets that circulate it throughout the body (2). The EC cell releases serotonin in response to mechanical and chemical stimulation, and this release differs depending on whether the body has been fed or is fasted (3). Gut-derived serotonin is important for regulating:

  • Stretch and contraction of the gut
  • Gut sensation
  • The ability for platelets to clot blood
  • Bone development
  • Blood pressure
  • Metabolism (1)

There are still many questions regarding how the EC cell releases serotonin. Recent studies from Dr. Beyder’s laboratory of Mayo Clinic discovered that a mechanosensitive ion channel called Piezo2 is present in human and mouse EC cells, and that Piezo2 is important for serotonin release in EC cell models after a mechanical force like pressure is applied (4, 5). In the broad scheme of things, understanding the role of Piezo2 in EC cell serotonin release and in regulation of blood serotonin levels could lead to future drug developments for gastrointestinal diseases.

A visual representation of serotonin release from EC cells and platelet uptake. Reference: Modified from Mawe & Hoffman. Nature Rev Gastro & Hep. 2013. (1)

Dr. Beyder’s laboratory created a mouse model with the Piezo2 gene knocked out of the gastrointestinal tissue lining the gut. These knockout mice can be compared to the control mice that do not have the Piezo2 gene removed to see how Piezo2 affects the physiology of the gut. My aims for my ten week research fellowship were:

  • To determine the role of Piezo2 in mechanosensitive EC cell serotonin release from primary EC cells from fed and fasted epithelial Piezo2 knockout and control mice
  • To determine the role of Piezo2 in systemic serotonin levels in fed and fasted epithelial Piezo2 knockout and control mice

As is the case with most research, everything did not turn out as planned!

In the first few weeks of my research project, I had already faced unexpected complications. I was planning to collect cells from mouse colon and place them on a special plate with the proper nutrients and environment to help them grow into what is called a primary culture. However, we were not able to take pictures to show that the primary cultures were present since we did not have a microscope lens that could fit the wells in the plate. With the limited time I had for the project, my team decided to focus on measuring whole gut serotonin instead. This highlights how quickly a research project can change and the many approaches a scientist can take to solve a problem. There were also times I would try a new technique to yield better results, but would ultimately go back to the original technique. Overall, the general research process was to look back to see how an experiment was done in the past, and then complete a series of trial and error cycles from there to optimize the protocol for my specific project.

After collecting and preparing samples, I ran a test called an enzyme-linked immunosorbent assay (ELISA) that quantifies the amount of serotonin in a sample.

Amid the journal clubs and experiments, this summer I learned about the collaborative efforts required to be successful as a scientist. I shared equipment and bench space with other researchers in the lab, so we had to coordinate a schedule so that everyone could complete their experiments. I enjoyed getting to know the other members of the lab, many with diverse backgrounds and specialties. Every week the department had a lab meeting where someone from each lab would take turns presenting research updates. It was a great opportunity to learn about other projects that related to the enteric nervous system and new adjustments made to fix problems. That being said, life as a researcher has its challenges. There were days I would spend hours preparing an experiment, only to made a mistake that could have been prevented if I would have asked the right person. If I had to give any advice from my summer experience, I would say don’t be afraid to ask for help – especially if you are feeling discouraged! Everyone in a lab develops his or her own expertise in something, which makes it impossible to know everything. But one of the beauties of science is that there is still a lot for us to learn, and sometimes the most frustrating failures can bring unexpected discoveries.

References

  1. Mawe GM, Hoffman JM. Serotonin signalling in the gut–functions, dysfunctions and therapeutic targets. Nature Reviews: Gastroenterology and Hepatology 10: 473-86, 2013; 10.1038/nrgastro.2013.105.
  2. Berger M, Gray JA, Roth BL. The expanded biology of serotonin. Annu Rev Med. 60: 355-66, 2009; 10.1146/annurev.med.60.042307.110802.
  3. Sumara G, Sumara O, Kim JK, Karsenty G. Gut-derived serotonin is a multifunctional determinant to fasting adaptation. Cell Metab. 16: 588-600, 2012; 10.1016/j.cmet.2012.09.014.
  4. Wang F, Knutson K, Alcaino C, Linden DR, Gibbons SJ, Kashyap PK, Grover M, Oeckler R, Gottlieb PA, Li HJ, Leiter AB, Farrugia G, Beyder A. Mechanosensitive ion channel Piezo2 is important for enterochromaffin cell response to mechanical forces. J Physiol. 595: 79-91, 2016; 10.1113/JP272718 PMCID: PMC27392819.
  5. Alcaino C, Knutson K, Gottlieb PA, Farrugia G, Beyder A. Mechanosensitive ion channel Piezo2 is inhibited by D-GsMTx4. Channels. 11: 245-253, 2017; 10.1080/19336950.2017.1279370.
Alecia Alto attends the University of Minnesota Rochester in Rochester, MN. She is a 2017 Undergraduate Summer Research Fellow (UGSRF) doing research in Dr. Arthur Beyder’s lab at Mayo Clinic in Rochester, MN.  After graduating with a bachelor or science in health sciences, she is considering a career as a physician scientist.