cell biology

 

Builders and Blocks – Engineering Blood Vessels with Stem Cells

Posted 17 September 2014 by Jalees Rehman

Back in 2001, when we first began studying how regenerative cells (stem cells or more mature progenitor cells) enhance blood vessel growth, our group as well as many of our colleagues focused on one specific type of blood vessel: arteries. Arteries are responsible for supplying oxygen to all organs and tissues of the body and arteries are more likely to develop gradual plaque build-up (atherosclerosis) than veins or networks of smaller blood vessels (capillaries). Once the amount of plaque in... Read more

Synthetic Biology: Engineering Life To Examine It

Posted 6 January 2014 by Jalees Rehman

Two scientific papers that were published in the journal Nature in the year 2000 marked the beginning of engineering biological circuits in cells. The paper "Construction of a genetic toggle switch in Escherichia coli" by Timothy Gardner, Charles Cantor and James Collins created a genetic toggle switch by simultaneously introducing an artificial DNA plasmid into a bacterial cell. This DNA plasmid contained two promoters (DNA sequences which regulate the expression of genes) and two repressors (genes that encode for proteins which suppress... Read more

Stem Cells and Their Fat Neighbors

Posted 19 November 2013 by Jalees Rehman

We recently published a PLOS ONE paper (Mitochondrial respiration regulates adipogenic differentiation of human mesenchymal stem cells) in which we studied how the metabolism of an adult stem cell can influence its ability to differentiate. Human bone marrow mesenchymal stem cells (also known as marrow stromal cells, marrow progenitor cells or MSCs) can be converted into fat (adipocytes), cartilage (chondrocytes) or bone (osteoblasts). The work performed by Yanmin Zhang and Glenn Marsboom in my lab showed that MSCs undergo a... Read more

Replicability of High-Impact Papers in Stem Cell Research

Posted 23 July 2013 by Jalees Rehman

I recently used the Web of Science database to generate a list of the most highly cited papers in stem cell research. As of July 2013, the search for original research articles which use the key word "stem cells" resulted in the following list of the ten most widely cited papers to date:   1. Pittenger M et al. (1999) Multilineage potential of adult human mesenchymal stem cells. Science 284(5411):143-147 Citations: 8,157   2.  Thomson JA et al. (1998) Embryonic... Read more

Flipping the Switch: Using Optogenetics to Treat Seizures

Posted 24 January 2013 by Jalees Rehman

Optogenetics is emerging as one of the most exciting new tools in biomedical research. This method is based on introducing genes that encode for light-sensitive proteins into cells. A laser beam can then be used to activate the light-sensitive proteins. Many of the currently used optogenetic proteins respond to the laser activation by changing the membrane voltage potential inside the cells. This is the reason why neurons and other cells that can be excited by electrical impulses, are ideally suited... Read more

Beautiful Animations of Cellular Processes

Posted 17 January 2013 by Jalees Rehman

The professional animator and molecular biologist Janet Iwasa at Harvard Medical School is generating beautiful animations of cellular processes such as proteasome structure and function or endocytosis. Importantly, she has published these on her website with a Creative Commons license so that everyone has access to them. She has been interviewed by EarthSky, where she explains why she became a molecular animator. Movie about the proteasome structure: Movie about chromosome segregation: Movie about protein translocation (movement of proteins across membranes):... Read more

Immune Cells Can Remember Past Lives

Posted 9 January 2013 by Jalees Rehman

The generation of induced pluripotent stem cells (iPSCs) is one of the most fascinating discoveries in the history of stem cell biology. John Gurdon and Shinya Yamanaka received the 2012 Nobel Prize for showing that adult cells could be induced to become embryonic-like stem cells (iPSCs). Many stem cell laboratories now routinely convert skin cells or blood cells from an adult patient into iPSCs. The stem cell properties of the generated iPSCs then allow researchers to convert them into a... Read more

Inspired By Snake Venom

Posted 1 January 2013 by Jalees Rehman

When I remember the 80s, I think of Nena’s 99 Luftballons, Duran Duran’s Wild Boys and ….snake venom. Back in those days, I used to be a typical high school science nerd. My science nerdiness interfered with my ability to socialize with non-nerds and it was characterized by an unnecessary desire to read science books and articles that I did not really understand, just so that I could show off with some fancy science terminology. I did not have much... Read more

Can The Heart Regenerate Itself After A Heart Attack?

Posted 5 December 2012 by Jalees Rehman

Some cardiovascular researchers believe that the heart contains cardiac stem cells or progenitor cells which can become mature cardiomyocytes (beating heart cells) following an injury and regenerate the damaged heart. The paper "Mammalian heart renewal by pre-existing cardiomyocytes" published in the journal Nature by Senyo and colleagues (online publication on December 5, 2012), on the other hand, suggests that the endogenous regenerative potential of the adult heart is very limited. The researchers studied the regeneration of cardiomyocytes in mice using... Read more

Is the Analysis of Gene Expression Based on an Erroneous Assumption?

Posted 26 October 2012 by Jalees Rehman

The MIT-based researcher Rick Young is one of the world’s top molecular biologists. His laboratory at the Whitehead Institute for Biomedical Research has helped define many of the key principles of how gene expression is regulated, especially in stem cells and cancer cells. At a symposium organized by the International Society for Stem Cell Research (ISSCR), Rick presented some very provocative data today, which is bound to result in controversial discussions about how researchers should assess gene expression. It has... Read more