Tag Archives: mitochondria

Detrusor, Urothelium and Mitochodria – Oh My!

The summer of 2018, I worked under Dr. Johanna Hannan at Brody School of Medicine in order to study sex differences in bladder dysfunction and study the impact of obesity-induced bladder dysfunction. With one-third of Americans, aged 40 years or older, reporting to have some level of urinary incontinence, we know that bladder dysfunction is a common condition.1 Both males and females experience bladder dysfunction, but they can experience varying degrees of stress or urge incontinence, overactive bladder, and obstructed bladder. Overall, females experience greater urinary incontinence compared to males.1 Our other interest, obesity induced bladder dysfunction, is pertinent because an increased BMI correlates with a higher risk of urinary incontinence. The mechanism that obesity-induced bladder dysfunction occurs is poorly understood. Specifically, we looked at the urothelium, the inner lining of the bladder responsible for signaling, and the detrusor smooth muscle, which contracts the bladder to dispel urine. Our interest within these tissues were mitochondria, the powerhouse of the cell, responsible for creating ATP; mitochondria is a model indicator of cell health. To study the health of mitochondria, we measured mitochondrial respiration within mice urothelium and detrusor smooth muscle layers of the bladder. Different substrates were added to promote or inhibit certain pathways within oxidative phosphorylation so that differences in mitochondrial metabolism could be studied. We believe that impaired mitochondrial function is contributing to the decreased contraction and inflammation that leads to bladder dysfunction in obese men and women.

Realities of Research

Working within a research lab is an experience you never forget. Life as a research scientist is different than what I had previously thought. It was not every day that I was running experiments; there were days where I read papers in order to understand and apply the results from the experiments. While we had originally believed that females would have decreased mitochondrial respiration because they had a higher prevalence of bladder dysfunction, the data obtained from an oxygraphy-2K (it measures oxygen within a chamber) showed that males actually had lower respiration. These results were found in the presence of a fatty acid which seems to impact male bladder metabolism. Though our hypothesis was proved wrong, our results are significant because they uncover novel information related to males having an impaired fatty acid metabolism.

The best part of working in a research lab was contributing to the field of science. Though our hypothesis was proved wrong, the data still had relevance to bladder dysfunction and how it impacts the population. Before our research, there was little to no information on bladder mitochondria in males and females. On the other hand, the worst part of research was when a machine would malfunction during the experiment. It not only compromised the results, but the tissue that was in it was also rendered compromised. Whenever this happened, there was always someone in the lab that I could ask for help. Also, this experience demonstrated that is it okay to ask for help – especially from people within the lab! They probably experienced the same problem and had their own tips and tricks to prevent it from happening again. Collaboration and discussion were encouraged in the lab; it is something I hope to continue to practice as I continue a career in science.




  1. org. (2018). American Urological Association – Bladder Health. [online] Available at: https://www.auanet.org/advocacy/bladder-health.


Hanna Kosnik is a junior at East Carolina University in Greenville, NC working towards majors in Biochemistry and Chemistry. She conducted research under Dr. Johanna Hannan in the Department of Physiology at Brody School of Medicine in Greenville, NC. Hanna is recipient of the 2018 Undergraduate Summer Research Fellowship (UGSRF) funded by the American Physiology Society (APS). After graduating, Hanna plans to pursue a career in medicine.
More Than a Powerhouse

Over the summer, I have been conducting research in Dr. Sathish Venkatachalem’s lab at North Dakota State University. Our lab investigates the effects of sex steroid hormones such as estradiol on asthma. Asthma currently affects 1 in 13 people in the United States and results in 14.2 million doctor’s office visits each year.1 In recent years it has been discovered that pre-menopausal women have a higher rate of asthma than men, suggesting a role of hormones (a chemical secreted from glands) in asthma.2 While men have a small amount of estradiol secreted into their bloodstream, pre-menopausal women have much more estradiol which helps to regulate the menstrual cycle among other functions. My project focuses on how different hormones in men and women could have an impact on asthma. My focus is specifically on a specialized structure in cells called mitochondria. Mitochondria are largely known for converting energy into a usable form of adenosine trisphosphate (ATP), but they also play many other roles. For example, mitochondria act as a reservoir for calcium within the cell which is important because calcium is an essential component of contraction, cell signaling, and nerve cell function, among other roles. My hypothesis is that if mitochondria are not functioning properly to buffer calcium, they cannot help with calcium regulation which may cause more contraction in the muscle cells surrounding the lung airway. As a result, the airway could narrow, and breathing could become difficult if not impossible. My project investigates how mitochondria change shape in asthmatic conditions and whether they are working together as a team to regulate calcium in cells. It is crucial for mitochondria to buffer calcium so that proper contraction and relaxation of the lung airways can occur. Proteins called Drp1 and Mfn2 regulate the fusion and fission process between mitochondria and are key in my investigations into mitochondrial morphology. Fusion proteins cause mitochondria to bind together, while fission proteins cause mitochondria to break apart. If too many fission proteins are present in mitochondria it can result in increased breakage and the failure to properly buffer calcium. In the future, mitochondria could be a target for treatment of asthma to reduce contraction and allow a patient to breathe more easily.


Image of mitochondria.

Research is quite different from other punch-in punch-out jobs I have had. Often, experiments demand that you come early or stay late to get results. I have been fortunate to work under a graduate student who has helped me prioritize which experiments need to be done and at what time. Through the summer, I have come across quite a few challenges and I have found that my critical thinking skills have been sharpened because of it. For example, at the beginning of the summer I was trying to identify a certain protein within my mitochondria, but it proved to be elusive at first. Through trial and error, I modified the protocol of the experiment until proper results were obtained. During those weeks, I felt discouraged because it was not exciting to repeat the same experiment multiple times over. However, I learned to problem solve through scientific protocols and I grew as a researcher because of it. The part of my project that I have found the most rewarding is taking images of my mitochondria. Results come quickly because the mitochondria absorb a dye quickly, then they light up under my microscope. I have learned to view the pictures of those mitochondria as art; the bright green squiggles that show up on the imaging screen never fail to amaze me and remind me of what I can do in this field.


Christy pictured in Dr. Sathish Venkatachalem’s lab at North Dakota State University.

Being a scientist in a lab for ten weeks has revealed to me the need for creativity in science. When I did not know how to proceed with an experiment or a result, I had to think outside the box, ask other scientists, or modify the protocol. Some days were exciting because the data turned out very well after many days of work. Other days were packed with processing mitochondrial data in front of a computer. I really enjoyed that my day-to-day experience in the lab was constantly changing due to the different experiments that I had the opportunity to run. I was also surrounded by brilliant scientists and colleagues that were willing to explain a finding to me or sharpen my skill at a certain technique in the lab. I have learned that science needs to be collaborative because many minds combined are better than one. I am grateful to the American Physiological Society for the opportunity to learn these lessons during ten weeks of research this summer.



  1. (2018, April 24). Retrieved from https://www.cdc.gov/asthma/default.htm
  2. Sathish V, Martin YN, Prakash YS. Sex steroid signaling: implications for lung diseases. Pharmacology & therapeutics. 2015; 150:94-108.
  3. (2015, April 26). [Image of mitochondria]. Retrieved from https://www.bbc.com/news/health-32434347
Christy Jesme is a senior at North Dakota State University in Fargo, ND. She is majoring in biology and minoring in chemistry and psychology while working in Dr. Sathish Venkatachalem’s lab. The lab investigates the role of sex steroid signaling on asthma. During the summer of 2018, Christy was awarded the Undergraduate Summer Research Fellowship funded by the American Physiological Society. She is currently in the process of applying to medical school in hopes of attending classes in the fall of 2019.
In the Lab for the First Time

Throughout the summer, I have been participating in what is my very first research experience. Apart from learning and doing techniques for the first time,  the biggest challenge this summer has been trying to explain what I have been doing for the past month and a half to people that have asked me. My host’s research laboratory works on trying to understand the molecular mechanisms behind heart diseases, specifically working with the mitochondria. This organelle, also known as the “powerhouse of the cell”, is the one responsible for producing energy inside the cell. My project is focused more on mitochondrial dynamics, the fusion and fission processes the mitochondria go through to maintain their relative stability, and the proteins that facilitate them. I have been working to measure and quantify the presence of these proteins in different populations of mitochondria; and recently, I have been checking to see if these proteins become acetylated in samples that have gone through ischemia/reperfusion. Ischemia/reperfusion injury, also known as IR, occurs when the heart tissue is deprived of oxygen and nutrients; then goes through a period of reperfusion, when blood rushes back into the system. This sudden re-oxygenation period causes damage to the heart tissue. If fusion and fission proteins have become acetylated, inactivated due to the addition of an acetyl group, they could be affecting the stability of the mitochondrial population and possibly furthering damage during IR injury.

Life as a Scientist

Being that this is the first time I’ve worked in a research laboratory, it’s been great to finally have the chance to apply some of the knowledge I’ve acquired in my classes to something tangible; or understanding how various subjects I’ve learned from are applied in real life. I’ve spent the last six or seven weeks learning and improving my techniques in order to measure protein expression.  In practices and even in actual runs, we’ve gone over procedures that take pretty much a whole day in order to eliminate possible errors with results. Currently, we’re working with the data we’ve gotten to see if we have to run more experiments in the next few weeks.

I guess the most surprising thing about this summer has been that the life as a scientist runs as a normal nine-to-five workday. Sure, there have been some instances that we stay later than usual or come in earlier to get things done; however, I had imagined something very different I suppose.  Working as part of a lab team has been a great experience, mostly because you learn to have responsibility as a scientist and a coworker. Many of the areas and materials are used by everyone in the lab, so it becomes your responsibility to keep everything organized and stocked. You tend to think about leaving things in the order that you would like someone else to leave them. Apart from that, helping anyone out in the team goes a long way, because at the end of the day, we are all working towards the same goal.

Roberto Guzmán is a sophomore majoring in Cellular Molecular Biology at the University of Puerto Rico, Río Piedras Campus. This summer, he is working in Dr. Sabzali Javadov’s lab at the University of Puerto Rico, Medical Sciences Campus. He is a Short-Term Research Education Program to Increase Diversity in Health-Related Research (STRIDE) Fellow funded by the APS and a grant from the National Heart, Lund and Blood Institute (Grant #1 R25 HL115473-01). After receiving his bachelor’s degree, he plans to obtain a MD and continue into health related research.