Tag Archives: hypertension

Novel Mechanisms of Preeclampsia Prevention via SGK1 and Corticosteroids

Preeclampsia, a hypertensive disorder in pregnancy, affects more than 6 million pregnancies per year worldwide. It is a dangerous condition during pregnancy which involves high blood pressure, proteinuria, and swelling. The Santillan lab has shown that single dose early of BMTZ early in pregnancy will reverse late pregnancy hypertension and proteinuria (1). The molecular mechanism by which this reversal occurs is unclear. One potential pathway involves serum/glucocorticoid regulated kinase 1 (SGK1), a serine/threonine kinase stimulated by corticosteroids. SGK1 dysregulation and human genetic variants in SGK1 have been associated with hypertension. The overall goal of this study is to determine whether SGK1 and its regulation play a role in preeclampsia.  If so, BMTZ has the potential to prevent preeclampsia in humans. Because mir-365 has been shown to decrease SGK-1 expression in human placentas from pregnancies with poor placentation, I will examine the effect of vasopressin and SGK1 in placental cells on mir-365 expression. In addition, it will be determined if placental mir-365a-3p is differentially expressed in human preeclampsia. This project is significant because it may help to determine how BMTZ protects from preeclampsia and whether BMTZ could be useful in humans.

 

Research in the lab can be very stressful. Things may not go as well as expected and troubleshooting is a process. Regardless, I had the opportunity to learn many new techniques that would help me in the future. I was surprised how research is comprised of so many different aspects. A little difference in one experiment may change the whole outcome. I learned a great set of skills like how to maintain a cell culture, perform an ELISA, BCA, and extract RNA. It took a while for me to start up on my experiments because I had to research some more background information to ensure I knew what I was doing. My experiments went smoothly, but it was later found that the drug I was using to treat the cells was not working in our mouse model; therefore, it may not be working with my cells as well. My project was put to a halt to first determine if the drug was correctly performing. The drug was aliquoted about a year ago and may have degraded. I would have to wait in order to determine whether I was able to continue or to start over. In the meantime, I worked with my mentor with small projects and learned useful techniques. Additionally, I worked on the second portion of my project involving whole placental tissues. The tissues were RNA prepped and analyzed via qPCR. The results showed that there was a significant difference with p-value of 0.016. This makes sense because Xu found that miR-365 negatively regulates IL-6 and it, in turn, is transcriptionally regulated by Sp1 and NF-κB. (2) So, transcriptional down-regulation of miR-365 should result in increased IL-6. This was interesting to hear, but we cell culture was needed to determine this and it was on standstill.

 

There were some busy days and other days there was a lot of down time. For example, one day there may be multiple tests to complete in a day, other days an experiment would consist of wait time. The most surprising part of participating in the lab is that I realized that a lot of the down time is used to write papers or grants. Research involves a great deal of writing to express the study to the public eye and document previous studies to help ongoing studies. I am appreciative of researchers because without those papers I would not have been able to understand my study without background information. Most days were very stressful trying to balance all of the work and trying to understand why a certain mechanism happened. My least favorite part during my time in the lab was working so hard on an experiment and in the end, not having it work out. The best part was working along with my mentor to learn new techniques and tests. I’m also glad that people around the lab worked well with one another and that they would take the time to reach out and teach me.

 

References:

  1. Santillan, M., Santillan, D., Scroggins, S., Min, J., Sandgren, J., Pearson, N., Leslie, K., Hunter, S., Zamba, G., Gibson-Corley, K. and Grobe, J. (2014). Vasopressin in Preeclampsia: A Novel Very Early Human Pregnancy Biomarker and Clinically Relevant Mouse Model. Hypertension, 64(4), pp.852-859.
  2. Xu et al. miR-365, a Novel Negative Regulator of Interleukin-6 Gene Expression, Is Cooperateively Regulated by Sp1 and NF-κB. Journal of Biochemistry 286: 21401-21412, 2011
Carolyn Lo is a junior majoring in Human Physiology and Biochemistry at the University of Iowa in Iowa City, Iowa. She is a 2018 Short-Term Research Education Program to Increase Diversity in Health-Related Research (STRIDE) Fellow working with Dr. Mark Santillan at the Carver College of Medicine in Iowa City, IA. Carolyn’s fellowship is funded by the APS and a grant from the National Heart, Lung and Blood Institute (NHLBI) (Grant #1 R25 HL115473-01). After graduation, Carolyn plans to pursue a doctorate degree in medicine.
Learning to Become a Researcher

When people or animals feel threatened, their sympathetic nervous system, a.k.a. ‘fight-or-flight’ system, releases chemicals that increase their blood pressure and heart rate to prepare for fighting or fleeing danger.  Unfortunately, when someone is obese or eats a chronically high-fat diet, their fight-or-flight system can be in an almost permanent state of overdrive.  This can place too much strain on the heart and blood vessels, potentially leading to hypertension (high blood pressure) and subsequent cardiovascular disease such as a heart attack or stroke.  My research project for the summer was to identify specific pathways in the mouse brain that influence the fight-or-flight response.  More specifically, I aimed to determine how inhibition of the dorsomedial hypothalamus (an area of the brain) by neuropeptide-Y (a brain-specific chemical messenger) leads to decreased activity in the fight-or-flight system.  By determining how various chemicals and pathways in the body and brain influence the fight-or-flight system, we may be able to find new treatments for people who have hypertension, hopefully increasing their longevity by decreasing their risk for serious conditions like heart attack or stroke.

 

Working in a research lab is simply amazing.  There is an almost endless amount of techniques, equipment, and software available to learn how to use.  This summer I have learned how to perform immunohistochemistry, how to use a confocal microscope, and how to utilize different analysis software programs to interpret results from fluorescent images.  If time permits, I may even learn how to perform microinjection surgery on a mouse and how to use RNAscope to complement my immunohistochemistry experiments.

 

Two things that surprised me about working in a research lab were how time-consuming experiments can be, and how expensive research supplies are.  For instance, it takes a minimum of sixteen days post-injection before the mouse brains are ready for me to begin processing them.  The brains must then be frozen, sectioned, immunohistochemically treated, mounted onto slides, then imaged, all of which adds up to around thirty hours of processing for a set of three or four brains.  Additionally, much of the processing utilizes expensive solutions and equipment, such as the $400 primary antibody used in the immunohistochemistry, or the fluorescent microscope which costs around $55/day to use for imaging.  This experience helped me to realize the importance of organization, precision, and time-management when conducting an experiment, since any mistake could result in hundreds of dollars wasted and countless hours lost.  Thankfully the experiments I’ve conducted so far this summer have turned out great, and I look forward to starting my next large batch of experiments next week.

 

The day-to-day life of a scientist is highly variable based on my experience this summer.  During any one week I might complete a variety of different tasks based on the needs of my research project as well as the needs of my lab colleagues. While there are general deadlines to be met for certain things and some experiments that require assistance from others, for the most part I am free to schedule which tasks I will be working on for any given day.  One downside to working in research is that since certain equipment is too expensive for each lab to have one of their own, it must be purchased and shared by the whole department.  For instance, the fluorescent microscope that I use is a very popular tool for the type of research done in our department, so you must make a reservation in order to use it.  Unfortunately, if your imaging is taking longer than expected and you didn’t reserve enough time on the microscope to finish, you could end up waiting an entire week before another reservation is available.  Thankfully, with careful planning, this problem can usually be avoided.

 

Overall, working in research as part of a team with the members of my lab has been wonderful.  Each person has their own unique background in research, and since I’m the most junior member of the lab there is a wealth of knowledge I can learn from each of them.  I truly appreciate how much each of my lab colleagues is willing to teach me what they know, provide answers to my questions, and give me guidance for not only my research project, but for my education and career goals as well.

 

Alyssa Bonillas is a senior at Portland State University in Portland, OR, majoring in both Biology and Psychology.  She is a Hearst Fellow working in Dr. Virginia Brooks’ lab at the Oregon Health & Science University in Portland, OR.  Alyssa’s fellowship is funded by APS through a grant from the Hearst Foundation.  After graduation, Alyssa plans to further her education by completing an MD/PhD program, and continuing on to become a physician-scientist at an academic research institution.
Summer with GPER

GPER KO Kidney with damage

This summer I worked in Dr. Sarah Lindsey’s lab at Tulane University School of Medicine. Dr. Lindsey’s lab explores the role of the G protein-coupled estrogen receptor (GPER) in vascular protection, specifically in relation to postmenopausal cardiovascular disease. At the start of the summer, I was trained in the field of histological pathology. This involves the examination of disease in tissue through techniques like staining and microscopic analysis. I applied different stains to tissues from mice kidneys, hearts, and aortas, to assess the protective effects of GPER in cardiovascular and renal damage in hypertensive mice. We predicted that mice without GPER would show more damage in their tissues than the control mice due to the protective qualities of GPER, specifically its role in the maintenance of extracellular matrices. This project is one of many the lab is conducting investigating the protective characteristics of GPER to judge its potential as a drug target in postmenopausal cardiovascular disease. This research could help alleviate the high levels of arterial stiffening seen in postmenopausal women.

 

Working with all the great researchers, technicians, and students in the lab this summer has taught me a lot about lab techniques and scientific concepts, but has also opened my eyes to what it is really like to work in a research lab. One of the most important skills I learned to value is patience. Science is vast and ever-growing, but it isn’t fast. I realized that a summer worth of research wouldn’t equate to fulfilling a project in its entirety- it takes time to acquire tissue sections from animals, conduct trials, and troubleshoot errors during experiments. This also means that working together with other members of the lab is crucial. Everyone has different areas of expertise, and they are all willing to contribute their knowledge to other’s projects to make the process run smoothly. I also learned that even though you start a project with a probable hypothesis, it is possible for your findings to reflect something totally different. Regardless, all findings are valuable, even if unexpected.

 

“Having ownership over a project gives agency to make decisions and learn techniques on your own.”

Working in a research lab is the optimal learning environment due to the flexibility and creativity it allows. In my lab, there are undergraduate students, graduate students, post-doctoral fellows, technicians, and a PI. This allows for a hierarchy of knowledge and expertise that provides a very comfortable environment for asking questions and learning from others. There will always be someone around to help if needed, and other projects to follow and learn from. However, there is also the opportunity to work on a unique project of particular interest to you. Having ownership over a project gives agency to make decisions and learn techniques on your own. Additionally, weekly lab meetings allow everyone in the lab to understand what others are working on, ask questions, and offer suggestions. This structure is ideal for those who like to work autonomously when desired, yet still receive aid and feedback when needed. It is a pleasure to be surrounded by such smart, driven people every day.

 

Ines Aguerre is an undergraduate senior majoring in Neuroscience and Sociology at Tulane University in New Orleans, LA. Ines is conducting cardiovascular and renal research under the guidance of Dr. Sarah Lindsey, an Assistant Professor at Tulane School of Medicine, also in New Orleans, LA. Ines is a recipient of the STRIDE Fellowship, which is funded by the APS and a grant from the National Heart, Lung and Blood Institute (Grant #1 R25 HL115473-01). After graduating from Tulane University, Ines plans on attending medical school in the hopes of becoming an MD and conducting more research.
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.
Science That Gets Your Blood Racing

Our lab studies cardiovascular diseases such as high blood pressure (hypertension), which affects roughly one third of American adults and puts them at a higher risk for heart disease and stroke, both of which are leading causes of death in the United States [1]. One of our overarching questions addresses the role that the tissue surrounding our blood vessels, or “perivascular adipose tissue” (PVAT), plays in obesity-related hypertension. PVAT contains various types of cells, including adipocytes (fat cells), endothelial cells, macrophages, lymphocytes, fibroblasts, and more [2]. We have previously shown that PVAT contains functional norepinephrine, a signaling molecule that constricts blood vessels and thus increases blood pressure [3]. My project addresses where and how PVAT actually stores this norepinephrine using the PVAT surrounding normal rat mesenteric resistance vessels- the small arteries and veins that branch into the small intestine and are important for blood pressure regulation. We hypothesize that it is specifically the adipocytes in PVAT that store NE, and that they use the vesicular monoamine transporter (VMAT) to do so. A better understanding of this mechanism is important for the future development of treatments for obesity-related hypertension.

[4] Sprague Dawley Rat. Photo Credit: Charles River

Realities of Research

When I first joined the Watts Lab a little over three years ago, I was a wide-eyed freshman who had never even used a micropipette before. Since then, my wonderful mentors have trained me in methods such as immunohistochemistry, brightfield and fluorescent microscopy, cell culture, handling and euthanizing rats, performing dissections, and isolating adipocytes from rat PVAT. More importantly, through these lab experiences, I have learned a scientific way of thinking and hypothesizing. This has been essential for my research project because it was incredibly challenging to develop a new protocol for the functional experiments using live adipocytes. It took over a year and endless troubleshooting for me to get to a point where I had a working procedure, and even longer to replicate the experiments to obtain a large enough sample size. One major obstacle was that freshly isolated adipocytes do not attach well to surfaces such as a microscope chamber slide. Additionally, one of the drugs I tested is only soluble in ethanol, which was toxic to the cells at most concentrations, so we had to find an alternative compound to use. Through trial and error, we have designed methods to effectively isolate, treat, and image PVAT adipocytes for this application. I am also very proud of the protocol we developed to quantify the fluorescent intensities of the cells I imaged, as it is crucial to analyze and present data in as objective and consistent a way possible. I was able to present our work in San Francisco at Council on Hypertension this past September, which was truly an incredible experience.

Conducting research in a lab has been one of the most rewarding adventures of my life. There is a certain thrill in knowing I am working to answer a question that no one else in the world is investigating in the same way. There are definitely setbacks that can be difficult to deal with, such as antibodies that do not work, cells that die for seemingly no reason, or not knowing how to begin designing an experiment you have in mind. However, this is why I love being a part of the scientific community- I have the opportunity to collaborate with the other scientists in our lab and department, or even at other institutions, to gain insight into how to better approach a research question. In addition to the hard work any researcher has to put into his or her own project, I believe it is this enthusiasm to help one another that ultimately allows all of us to be successful. Oh, and a little bit of luck never hurt anyone!

References

  1. High Blood Pressure Fact Sheet [Online]. Centers for Disease Control and Prevention. Centers for Disease Control and Prevention: 2016. https://www.cdc.gov/dhdsp/data_statistics/fact_sheets/fs_bloodpressure.htm [14 Jul. 2017]. 
  2. Miao CY and Li ZY. The role of perivascular adipose tissue in vascular smooth muscle cell growth. British Journal of Pharmacology 165(3): 643-658, 2012. 
  3. Ayala‐Lopez N, Martini M, Jackson WF, Darios E, Burnett R, Seitz B, Fink GD, Watts SW. Perivascular adipose tissue contains functional catecholamines [Online]. Pharmacology Research & Perspectives: 2014. http://onlinelibrary.wiley.com/doi/10.1002/prp2.41/full [14 Jul. 2017]. 
  4. CD® IGS Rat Crl:CD(SD) [Online]. CD® IGS Rat | Charles River. http://www.criver.com/products-services/basic-research/find-a-model/cd-igs-rat?loc=US [14 Jul. 2017].
Maleeha Ahmad is a senior majoring in Genomics and Molecular Genetics at Michigan State University in East Lansing, MI. Her Summer 2017 Undergraduate Research Excellence Fellowship (UGREF) gave her the opportunity to continue working in Dr. Stephanie Watts’s lab at Michigan State University, where she has been conducting research for the past three years. Maleeha’s fellowship is funded by the APS. After graduation, she plans to attend medical school and be involved in clinical research.
Neural Networks of Hypertension

Chronic high blood pressure, also known as hypertension, affects one in every three adults in the United States and nearly 1 billion people worldwide. It has been shown that the hormone, Angiotensin II (ANG-II), acts within the brain to stimulate the sympathetic nervous system, leading to hypertension. A region in the brain that is particularly sensitive to ANG-II and is involved in hypertension is the subfornical organ (SFO). The SFO is connected by neural projections to the paraventricular nucleus of the hypothalamus (PVN), and this pathway has been suggested to be important in cardiovascular regulation. The hypothesis of my study is that endoplasmic reticulum (ER) stress in the SFO-PVN projecting neurons is a cause of ANG-II hypertension. To test my hypothesis, the study will be split into two portions. In the first set of experiments, we will use staining of brain tissue (immunohistochemistry) to evaluate whether infusion of ANG-II causes ER stress in SFO neurons that send projections to the PVN.  If we find ER stress in these neurons, we will use genetic approaches (CAV2-Cre-GFP and AAV2-Flex-GRP78) to inhibit ER stress and determine whether this also prevented ANG-II hypertension from developing.

What did you learn working in the lab?

Working in Dr. Young’s lab has been enlightening, exciting, and frustrating at times. There are many skills that take a great deal of practice to master that are required for studies like this one. For example, in order to perform Immunohistochemistry to identify markers of ER stress in the brains—a technique I learned this summer—I first had to learn to use a cryostat to precisely slice and collect the brains onto glass slides. I sliced dozens of practice brains before I mastered the skill and even now after weeks of practice, I still face challenges and make mistakes while performing this task. I also learned skills like suturing, small procedures, injections, bench work, and many others.

I very much enjoy the lab environment. It is great to have such a close-knit team that genuinely wants to help each other succeed. I wasn’t anticipating the level of team work involved in running a research lab, but that is truly the foundation. I would say that the friendships are the best part of working in a lab. The worst part of working in the lab is the waiting. For example, I surgically placed ANG-II osmotic pumps in the mice and then had to wait two weeks before taking the next step in my study. During that time, I practiced on the cryostat a lot, but there was still significant down time that I filled with tasks unrelated to my project such as helping other lab members with their work, cleaning, etc.

Melanie Judice is a senior majoring in Biology at the George Washington University in Washington, D.C.. She is an Undergraduate Summer Research Fellow (UGSRF) working in Dr. Colin Young’s lab at the George Washington University. Mary’s fellowship is funded by the American Physiological Society. After graduation, Melanie plans to continue research in the Young lab while pursuing entry into the medical field.