Monthly Archives: January 2019

The Effect of Acidic or Neutral Environment on the Mitochondrial Morphology of Human Kidney Cells

This summer, I had the opportunity to investigate the effect of environmental acidity on the mitochondrial shape of human kidney cells.

African Americans have a much higher chance of getting kidney disease than European Americans because they frequently carry risk mutations in a gene called APOL1. Two mutations, termed as G1 and G2, have been discovered only in African American populations. Those who carry two copies of G1 or G2 variants are more likely to develop chronic kidney disease (CKD). Thirteen percent of African Americans carry two copies of APOL1 variants, and these two variants contribute to at least 70% of CKD in this population (Science, 2010). However, only 20% of African Americans with two copies of APOL1 gene variants eventually develop CKD. Therefore, we believe there must be a “second stressor” working together with the APOL1 variants to cause CKD. Prior studies at Wake Forest School of Medicine have concluded that APOL1 G1 and G2 variants induced malfunction of the mitochondrion, a critical organelle providing energy for normal cell activity (Ma, JASN 2017). An acidic environment may have additional negative effects on cells carrying defective APOL1 G1 or G2 variants, for two reasons. The first reason is that the protein encoded by the APOL1 gene variants is sensitive to acid and an acidic environment affects its function (Thomson and Finkelstein, PNAS 2015). The second reason is that kidney tissue accumulates more acid than other tissues in the body and presents an acidic environment that may affect the function of APOL1 protein or potentially be that “second stressor”.

This mitochondrial network image was taken with confocal microscopy during the 2018 APS undergraduate summer research program

Therefore, we investigated how the difference in environmental acidity level, defined by pH value, affects the mitochondrial shape of cultured human kidney cells — that is whether the mitochondrial pattern is normal or fragmented in the cells exposed to environments of different acidity (=different pH). We performed confocal microscopy to scan serial images of mitochondria from human kidney cells expressing normal APOL1 G0 and G1/G2 variants, and used Fiji software to measure the relative mitochondrial length. These experiments were done when APOL1 expression levels were comparable among cells of different APOL1 genotypes, and the cell viability was intact when APOL1 was moderately expressed. We found that an acidic environment enhanced the negative effect of APOL1 risk variants on the mitochondrial pattern of kidney cells. According to these preliminary experiments, an acidic environment appears to elicit more mitochondrial fragmentation, which typically suggests that mitochondria may not be working properly.

Our preliminary studies suggest that the effect of environmental acidity in the kidney may be important for understanding how APOL1 variants pose a high risk for CKD in the African American community. Understanding why products of APOL1 gene variants, which are expressed around body, damage only the kidney and how and why kidney disease develops in those individuals who carry G1 and G2 variants of this gene will have a huge impact on the African American community and help in the fight against kidney disease. This study is also a part of the larger project to identify other possible “second stressors” to APOL1 gene associated kidney disease, and relatively high environmental acidity of the kidney may be one of those.

 

Realities of Research

When I first came into the lab, my mind was filled with awe and admiration because I saw how dedicated the lab members were every day. I have found that scientific research is such a complex process. In order for a research project to be successful, every step of the experiment should be planned ahead of time and in minute detail. My mentor and lab instructor have been so considerate. They discussed every aspect of the experiment, such as when to seed cells, when to add doxycycline, when to purify and extract RNA from cells, etc. This allowed me to perform the experiments efficiently and saved me a lot of time so that I would not make too many mistakes and have to start all over again. Without their instruction and guidance, I cannot imagine how I could have done the cell culture (including doxycycline controlled gene overexpression), taken images on the confocal microscope, isolated RNA from cultured cells, and run RT-PCR all in a short period of ten weeks. The procedures were overwhelming to someone like me who had no previous experience with cell experiments. After the first two weeks of “playing” with cells, I realized it is delicate work requiring patience and fine motor skills. For example, I struggled opening and closing the cap of the falcon tube only with one hand or pipetting minute amounts of fluid for PCR experiments. After several rounds of practice, I felt comfortable performing the task. Now, I have a true understanding of “practice makes perfect”. To analyze the mitochondrial patterns, we used a new technique called Fiji/MiNA software to measure the length of the mitochondria of kidney cells. Based on literature, Fiji/MiNA software was used to measure the length of mitochondria in neuron cells. We adopted this software and successfully adjusted the settings to apply to mitochondrial lengths in kidney cells and accurately captured the small fragments of mitochondria, which made the measurement more precise. Thanks to my mentor and lab instructor, their dedication and precision greatly influenced me. From time to time, my mentor praised me for my contributions to the study. As a team, we have been able to complete the study and obtain our results as we expected.

 

Life of a Scientist

Doing scientific research has always been my passion. Since my high school years, I longed that someday I could make new discoveries, which would eventually change people’s lives. Working in the lab, I have been so excited to learn new techniques needed to complete my project. I never get tired of tedious repeats of 200 scans of images. The best part of the fellowship is that I have a tremendous amount of guidance from my mentor to successfully complete the project in the time limit and obtain the results we are expecting. I have realized that scientific research not only requires patience and proper time management, but also requires thorough knowledge from a variety of disciplines such as physiology, anatomy, molecular/cell biology, etc. This is quite challenging for me as an undergraduate. I shared the frustrations of other fellows, whose experiments did not go as planned. They had to rely on trial and error, and were even unfortunate to find out that there was not enough knowledge to do the study in their lab and started moving in another direction. The worst part of my research project was that I had to spend days measuring and recording the mitochondrial lengths of human kidney cells after treatment with different pH solutions using software and manually enter the data first in Word, then into an Excel spread sheet. But overall, being a scientist especially working as a team member of this lab filled me with joy and pride as we were rewarded with a successful project.

 

DengFeng Li is a junior majoring in Biology at the University of North Carolina at Greensboro. He is a 2018 APS Undergraduate Summer Research Fellow working in Dr. Snezana Petrovic’s Lab at Wake Forest University School of Medicine. Li’s fellowship is funded by the APS and a grant from the National Institutes of Health.
STRIDE, Statins, and Scientific Research: The Perfect Way to Spend Summer Vacation

After googling the definition of the word science, one will find that it means “the intellectual activity encompassing the study of the structure and behavior of the physical world through observations and experiments.” In simpler terms, science is about being curious and learning all that one can about something in order to better understand it. That is exactly what I have had the opportunity to do this past summer under the APS STRIDE fellowship program.

 

Research Project

 In scientific research, to start designing a project, one must first come up with or ask a question that nobody really knows the answer to. With that, something many people don’t know is that high cholesterol has no symptoms; therefore, many people do not even know they have high cholesterol levels. And those who are being diagnosed are being prescribed medication to lower their risk for developing heart disease and decreasing their chances for having a stroke (2). These medications being prescribed, called statins, are one of the most effective cholesterol-lowering drugs available. However, approximately 10-12% of patients taking statins develop muscle pain and dysfunction, which can be intensified with exercise (1). It is unclear as to how exercise and statins work in combination to yield these side effects. Yet, it is important to gain a better understanding as to how they work together to affect one’s health. Therefore, I have been currently researching the effects of the mixture of these two treatments in ApoE-/- mice, whom genetically have high cholesterol, in hopes of generating new insight as to how statins and exercise impact the health of individuals with hypercholesterolemia to contribute to the development of the most successful treatment options that decrease the severity of complications (3).

 

Realities of Research

This fellowship has allowed me to develop not only a greater understanding for the science behind the subject of the project itself, but also for the process and effort to perform and accomplish the project as a whole. What is fascinating about conducting research is that each day presents something different to be accomplished or overcome. I was most surprised by how much planning, preparation, and practice must be done prior to the actual start of a project. Whether it is acquiring supplies, matching up schedules, or deciding what types of experiments to conduct, it all takes time and dedication to ensure that the project runs smoothly. With that, I also had to learn and practice new techniques, such as injecting the mice with statin medication, training the mice, performing muscle dissections, and developing tissue samples to analyze protein levels. With what we’ve accomplished so far, there is no specific data that indicates a major difference between the effects of exercise alone and exercise in combination with statin in mice with high cholesterol. However, we hope to see some difference in muscle force between the two groups after we finish our experiments, in which we then plan to determine if there is a cellular basis that is being affected by the statin medication that is causing a difference. And if there’s no variance, then we know that this specific model doesn’t support our original theory. We would next look at a different element of force, such as endurance instead of strength. But the reality and beauty of research is that you never know what you’re going to find.

Life of a Scientist

Not knowing what to expect is one of the best and worst parts of the life of being a scientist. It is not a typical Monday through Friday 9:00am – 5:00pm job where you do the same thing every single day. You’re constantly learning new things and applying what you have learned to something new; you make connections from the past to the present to try and understand how concepts are related yet different. But even with these enlightening moments, there can be downsides, too. Challenges are thrown at you every day, whether it’s scheduling conflicts, flooding issues, or the results don’t turn out like you expected. Again, that’s where the art of science comes along, in that one must learn how to overcome these obstacles by becoming adaptable to every situation, thinking creatively to find a new route or how one can stay on their original path, and collaborating with others to share ideas as how to approach each step.

This summer has been about STRIDE, statins, and scientific research all of which have inspired me to never stop learning, to never stop questioning, and to never stop searching for an answer. It doesn’t matter if one is titled as a scientist or not, these are actions everyone should implicate into their lives to learn about themselves and their passions and to learn more about the world around them.

 

McKenzie Temperly is a junior majoring in Health Sciences – Clinical & Applied and minoring in Chemistry at Drake University in Des Moines, IA. She is a 2018 Short-Term Research Education Program to Increase Diversity in Health-Related Research (STRIDE) Fellow working in Dr. Kimberly Huey’s lab at Drake University.  McKenzie’s fellowship is funded by the American Physiological Society and a grant from the National Heart, Lung, and Blood Institute (Grant #1 R25 HL115473-01). After graduation, McKenzie plans to attend medical school and pursue an M.D./Ph.D. degree. She is currently interested in specializing in general/orthopedic surgery or emergency medicine intermixed with biomedical research within her chosen field.
Ozone: Protector or Pollutant?

We usually hear that we want more ozone in our atmosphere to protect us from the sun’s ultraviolet rays, but ozone isn’t always a good thing. That protective ozone is found in the stratosphere, while ozone on ground level is a harmful air pollutant caused by emissions from cars and factories. Ozone can do a lot of damage to human lungs, causing shortness of breath, coughing, inflammation and damage to airways, aggravation of lung diseases like asthma, and permanent lung damage. In response to ozone-induced injury, macrophages (immune cells which eat and break down viruses, bacteria, and dead cells) accumulate in the lung and contribute to inflammation and toxicity. Inflammation is important to get rid of any dangerous invaders or cell debris, but macrophages can also have damaging effects in the lungs.

We want to find out what can be done to reduce that inflammation and toxicity, so we are investigating valproic acid. Valproic acid is a fatty acid which has been shown to be anti-inflammatory and an antioxidant. My research project involves testing our hypothesis that valproic acid will reduce lung inflammation and toxicity caused by ozone-induced injury. To evaluate the effects of valproic acid on inflammation and toxicity, I stain thin slices of lung tissue by immunohistochemistry. In immunohistochemistry, the goal is to determine if alveolar macrophages are expressing markers of inflammation or toxicity – the more expression of a certain marker, the darker the macrophage should be stained. We expect that the lungs of mice treated with valproic acid will be less stained than the untreated if inflammation and toxicity are mitigated.

https://www.edf.org/health/why-smog-standards-are-important-our-health

Caption: Smog over LA. Ozone is the main component in smog.(1)

 

Realities of Research

Like the bad and good faces of ozone, doing a research in the lab is slow-going, but also rewarding. The pace is slow because I dedicate a lot of time to troubleshooting the immunohistochemistry process. For each marker of interest, the protocol needs to be optimized. This is time-consuming because it means going through the immunostaining process repeatedly, changing small details each time. It was especially frustrating when the results were not what we expected. When our controls were repeatedly turning out different from how they had looked in previous experiments, we had to figure out if it was the fault of the sample, a detail in the protocol, or the antibody. I’m currently still working on figuring out the discrepancy by testing samples from other labs and different antibodies. If it’s the samples that are faulty, we will put a hold on the immunohistochemistry until we can use the samples from an animal exposure we have planned in a couple of weeks. If the antibodies are the problem, we will order new ones. If I’m doing something in the protocol incorrectly, my research mentor will watch me go through the steps and find out. This complication has been slowing down our progress, but it’ll be rewarding to finally figure it out and get data.

Life of a Scientist

Even excluding the satisfaction of getting data, I feel like I’ve grown a huge amount working as a scientist this summer since it was completely new for me. It’s my first experience working full-time, in addition to taking place in the unique environment of a research lab. I was happily surprised by the amount of flexibility in schedule – each person comes in and leaves when they need to, depending on the work they need to get done that day. Some days are a typical 9 to 5, some might be much shorter, and some might go late into the night. It can become overwhelming meeting new people, catching up on literature, and learning new lab techniques. However, it’s also satisfying to soak up so much new information so quickly and see myself developing as a scientist and a student every week. In my experience so far, the best part of working full-time is the people I have been able to get to know. Seeing the lab tech, the faculty, the grad students, the undergrads, and the high school students every day gives me the chance to really learn about what they do inside and outside the lab. Because of them, coming into the lab every day is welcoming and exciting, which makes all the difference when I’m frustrated with my experiments. Working with them is easy and most of all, fun, and I’m grateful I was able to do research with such encouraging and friendly people.

 

References:

  1. Why smog standards are important for our health. (2018). Retrieved July 27,2018, from https://www.edf.org/health/why-smog-standards-are-important-our-health
Jordan Lee is a junior studying molecular biology and biochemistry at Rutgers University in New Brunswick, NJ. She is a 2018 Undergraduate Summer Research Fellow, funded by the APS. Jordan is working in Dr. Debra L. Laskin’s lab at the Ernest Mario School of Pharmacy at Rutgers. After graduation, she plans to continue doing research and exploring her interests in healthcare and science.