Mammals can regenerate tissues too!

Have you ever considered how cool it is that lizards can re-grow their tails? Wouldn't it be awesome if you could re-grow your arm if you needed to (say after an unfortunate quidditch match)? Well, although the recent report by Ashley Seifert and colleagues in Nature doesn't claim to be able to re-grow human limbs, it does suggest promise in the area of regeneration of mammalian tissues.

                In the September 27^th issue of Nature, Seifert and colleagues report that African Spiny Mice (genus Acomys) are capable of skin and cartilage regeneration. You may be thinking “so what? When I cut my arm, my skin regrows. No big deal” and in a way you are right. The difference is subtle but essential. When you get a cut, your skin undergoes a process called wound healing, which involves development of scar tissue. Seifert found that laboratory mice (genus Mus) undergo a wound healing and scaring process as well. The African Spiny Mice, however, do not develop scar tissue, but rather a distinct regeneration of new skin tissue, including hair follicles, and adipose (fat) tissue. In fact, when the injury occurs on the ear, the African Spiny Mouse can even regenerate the cartilage of the ear.

                This paper provides evidence that some mammals have the ability to regenerate tissues. Additional evidence also suggests that lab mice can begin the regeneration process but are not able to maintain it. This raises the possibility that lab mice (and perhaps even humans) have an intrinsic ability to regenerate, but may require additional direction (perhaps by factors not expressed in adult tissues) to do so. The most important implication of this research is stated clearly by the authors “[African Spiny Mice]…provides an idea model system in which to examine epimorphic regeneration in mammals.”

Paper referenced: http://www.nature.com/nature/journal/v489/n7417/full/nature11499.html

Post Authored by Sally

Melissa's Musings: Where do you keep the water?

Yesterday I started working in a new lab. The hardest thing about it is I have no idea where anything is. It’s sort of like cooking in someone else’s kitchen; you know what everything is and how it all works, but you can’t get anything done because you can’t find what you need. So you can either search through every drawer and cabinet yourself, or ask every thirty seconds “where’s this?” Either way, you feel dumb. Or at least I do. I guess I can take comfort in knowing it’s just part of the transition. I’ll eventually figure it out.

Post Authored by Melissa

Melissa's Musings

I wish I could take a picture every time I tell someone that I’ll be in grad school for at least 6 years. I would make a collage of their faces and tape it to my lab bench so I could have something to laugh at when my experiments fail. Because when you’ve been doing the same thing for two weeks without any success, all you can do is laugh…and hope it works before your advisor comes back into lab again.

Post authored by Melissa

Editor’s note: Melissa’s Musings is a weekly-ish column in which Melissa reflects on various aspects of pursuing a PhD in biomedical sciences.

Leukemia Invasion: Is Your Brain Safe?

This is not an invasion of parasitic aliens wishing to control your brain, or of zombies desiring to make a snack of it, but rather of your own cells gone rogue. It turns out that most of us are probably safe from invasion by rogue cells (I make no claim about zombies or aliens). But for a small part of the population, primarily children, the brain is not safe from leukemic invasion.

This small part of the population has a type of leukemia that effects T-cells (a type of white blood cell that monitors the body for pathogens) called T-cell acute lymphoblastic leukemia (T-ALL). ALL (encompassing both T-cell type and B-cell type) is the most common form of cancer in children age 1-7. For patients with this type of leukemia prognosis is usually good, however about 30% of patients will relapse within two years. Silvia Buonamici and her colleagues¹ investigate one cause of relapse in which leukemic cells enter the brain. It has long been known that in some patients with T-ALL the brain is invaded by leukemic cells, leading to the current broad therapy. In addition to chemotherapy which a patient receives against leukemia cells, they also receive radiation therapy to the head as a preventative measure. For the patients who are cured of the leukemia, this head radiation therapy often reduces the quality of life by causing new cancers, growth defects, developmental and learning difficulties, and other negative side effects. This is especially devastating to children for whom growth and development is essential.

Buonamici and her colleagues at New York University Cancer Institute investigate the molecular basis for leukemia invading the brain in order to develop better therapies. By using mice that develop T-ALL, Buonamici and her colleagues investigated how the leukemic cells invade into the brain. They looked at thin slices of the brain to identify T-cells (which look different from normal brain tissue) under the microscope. T-cells do not normally accumulate in the brain, so the ability to visualize them in normal brain structures allowed Buonamici and her colleagues to assess if the leukemic cells had invaded. With this ability to assess the invasion, they investigated the difference between leukemic cells that invade the brain, leukemic cells that do not invade the brain, and normal T-cells. They found a specific molecule on the surface of the leukemic cells, called CCR7, which allows the leukemic cells to enter the brain. Buonamici and her colleagues also identified a molecule expressed on the surface of brain cells, called CCL19, which is required for invasion of leukemia cells into the brain. These two molecules are like a lock and key to the door of a house. CCR7 is the key on the surface of the leukemic cells, CCL19 is the lock on the surface of brain cells, and entering the brain is like entering the door of the house. If you do not have the correct lock and key pair, you cannot get into the house. By identifying this lock and key pair, Buonamici and her colleagues have opened the door for future scientists to design a therapeutic drug that prevents the key from turning in the lock, therefore blocking leukemic cells from entering the doorway to the brain.

Buonamici and her colleagues focus in this paper on a specific type of T-ALL that is induced by an activated form of Notch1, a molecule that normally participates in growth and differentiation decisions (such as whether to become a T-cell or a B-cell). The amount of CCR7 (our key) on the surface of a leukemic cell is increased by Notch1 (like a locksmith making many copies of your key). Notch1 is activated in 80% of T-ALL patients, leading to the question: What causes leukemic invasion in the other 20% of patients? This question could be especially important to therapeutics because it is unclear what proportion of the 30% of relapse patients overlap with the 20% of patients without activated Notch1.

Paper Referenced

Buonamici, S. et al. (2009). Ccr7 signalling as an essential regulator of CNS infiltration in t-cell leukaemia.Nature, 459. Retrieved from http://www.nature.com/nature/journal/v459/n7249/full/nature08020.html doi: doi:10.1038

Post authored by Sally Trabucco

Science is Hard

This blog will make you smarter (statement not evaluated by statistically significant research). It will hopefully provide you with a way to read about biomedical research in an easy and fun way. It will contain occasional updates from the world of biomedical science. These will be entries based mostly on primary literature (AKA journal articles) of interesting biological and medical significance. The idea is based on an assignment from my first year of graduate school writing class. We were required to read a scientific article and then write a blog style paper about it for someone who only has a basic understanding of biology (like a freshman college biology course). This probably does not sound very difficult, but for someone who is so immersed in the world of science, learning to use lay terms can be challenging. Explaining something like performing an RNAi screen can be very difficult when the lay person probably doesn’t know what RNAi is. During our class the Vice Chancellor of Communications at UMass Medical School, Edward J. Keohane, gave a lecture on communicating with the lay person. He emphasized this as an important task for us, as student pursuing a PhD in the biomedical sciences, in order to communicate our research and findings to different groups of people. Most important of these groups (in my opinion), is the taxpayer. Paying taxes sucks. But we all agree to do it in exchange for something; protection from criminals on a local (city police), regional (state police), national and international level (armed forces, CIA, FBI, etc), education for our children at least through high school, and the advancement of science, among many other things. In my mind, the American (and Massachusetts) taxpayer pays me to research cancer and find new treatment options. This means that the most important people I need to communicate with are the taxpayers. The people trust me to do the research that will make a difference, and who will ultimately benefit from my contributions.
Although I think effective communication to a lay audience is important, I also think the exercise of writing a blog style paper is especially good for our growth as scientific leaders and teachers. I have heard a quote (some online attribute it to Albert Einstein, but I honestly don’t know for sure) that says

“If you can’t explain it to a six year old, you don’t understand it yourself”.

Writing a blog about a heavily scientific paper for someone with only a basic understanding of biological concepts forces us to boil down all of our complex ideas and techniques into simple explanations and concise thoughts. Most importantly it forces us to examine the work to try and answer the question “who cares?”. If the answer is “no one” then it signals to us that it is time to rethink our research goals.
I will start the first few entries of this blog by posting entries that resulted from the writing class assignment to give a broad range of topics. I focus my research on cancer, but there are a lot of other interesting areas of research going on every day and I hope to cover those as well. Any suggestions for articles to blog about or general ideas are encouraged!

Post authored by Sally Trabucco