‘Genetic doppelgangers:’ Emory research provides insight into two neurological puzzles

An international team led by Emory scientists has gained insight into the pathological mechanisms behind two devastating neurodegenerative diseases. The scientists compared the most common inherited form of amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD) with a rarer disease called spinocerebellar ataxia type 36 (SCA 36). Both of the diseases are caused by abnormally expanded and strikingly similar DNA repeats. However, ALS progresses quickly, typically killing patients within a year or two, while the disease Read more

Emory launches study on COVID-19 immune responses

Emory University researchers are taking part in a multi-site study across the United States to track the immune responses of people hospitalized with COVID-19 that will help inform how the disease progresses and potentially identify new ways to treat it.  The study is funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health. The study – called Immunophenotyping Assessment in a COVID-19 Cohort (IMPACC) – launched Friday. Read more

Marcus Lab researchers make key cancer discovery

A new discovery by Emory researchers in certain lung cancer patients could help improve patient outcomes before the cancer metastasizes. The researchers in the renowned Marcus Laboratory identified that highly invasive leader cells have a specific cluster of mutations that are also found in non-small cell lung cancer patients. Leader cells play a dominant role in tumor progression, and the researchers discovered that patients with the mutations experienced poorer survival rates. The findings mark the first Read more

Ravi Bellamkonda

CV cell therapy: bridge between nurse and building block

In the field of cell therapy for cardiovascular diseases, researchers see two main ways that the cells can provide benefits:

*As building blocks – actually replacing dead cells in damaged tissues

*As nurses — supplying growth factors and other supportive signals, but not becoming part of damaged tissues

Tension between these two roles arises partly from the source of the cells.

Many clinical trials have used bone marrow-derived cells, and the benefits here appear to come mostly from the “paracrine” nurse function. A more ambitious approach is to use progenitor-type cells, which may have to come from iPS cells or cardiac stem cells isolated via biopsy-like procedures. These cells may have a better chance of actually becoming part of the damaged tissue’s muscles or blood vessels, but they are more difficult to obtain and engineer.

A related concern: available evidence suggests introduced cells – no matter if they are primarily serving as nurses or building blocks — don’t survive or even stay in their target tissue for long.

Transplanted cells were labeled with a red dye, while a perfused green dye shows the extent of functional blood vessels. Blue is DAPI, staining nuclear DNA. Yellow arrows indicate where red cells appear to contribute to blood vessels.

Transplanted cells were labeled with a red dye, while a perfused green dye shows the extent of functional blood vessels. Blue is DAPI, staining nuclear DNA. Yellow arrows indicate where red cells appear to contribute to green blood vessels. Courtesy of Sangho Lee.

Stem cell biologist Young-sup Yoon and colleagues recently published a paper in Biomaterials in which the authors use chitosan, a gel-like carbohydrate material obtained by processing crustacean shells, to aid in cell retention and survival. Ravi Bellamkonda’s lab at Georgia Tech contributed to the paper.

More refinement of these approaches are necessary before clinical use,  but it illustrates how engineered mixtures of progenitor cells and supportive materials are becoming increasingly sophisticated and complicated.

The chitosan gel resembles the alginate material used to encapsulate cells by the Taylor lab. Yoon’s team was testing efficacy in a hindlimb ischemia model, in which a mouse’s leg is deprived of blood. This situation is analogous to peripheral artery disease, and the readout of success is the ability of experimental treatments to regrow capillaries in the damaged leg.

The current paper builds a bridge between the nurse and building block approaches, because the researchers mix two complementary types of cells: an angiogenic one derived from bone marrow cells that expands existing blood vessels, and a vasculogenic one derived from embryonic stem cells that drives formation of new blood vessels. Note: embryonic stem cells were of mouse origin, not human. Read more

Posted on by Quinn Eastman in Heart Leave a comment

Herding terrorist cats

Wikipedia says that “herding cats” refers to an attempt to control or organize a class of entities that are uncontrollable or chaotic.

Cancer cells certainly qualify as uncontrollable or chaotic, so the metaphor could apply to a recent Nature Materials paper from Georgia Tech and Emory’s Ravi Bellamkonda – a member of Winship Cancer Institute.

Glioblastoma is the worst of the worst: the most common and the most aggressive form of brain tumor in adults. The tumors are known to invade healthy tissue and migrate along white matter tracts and blood vessels. Bellamkonda and his colleagues devised a strategy for luring glioblastoma cells out of the brain by offering the cells attractive nanofibers that the cells will Ray Ban outlet attempt to invade. When the cells arrive, they undergo apoptosis — cellular suicide. He has called this “an engineer’s approach to brain cancer” (in a lecture a couple months ago) and “the Pied Piper approach” (in the video below).

(It’s not the first time Bellamkonda has unfurled dazzling technology against glioblastoma, developed with an Emory collaborator.)

Bellamkonda’s collaborator this time, Tobey Macdonald, director of pediatric neuro-oncology at Children’s Healthcare of Atlanta, is credited in the paper with coming up with the aspect of the strategy that was based on the molecule cyclopamine. This earlier story from CHOA provides more background on how the collaboration came together.

Cyclopamine

Cyclopamine is key to the “lure ’em out and kill ’em” strategy. Most high-grade brain tumors overproduce a protein called Sonic Hedgehog, spurring their growth. Cyclopamine is selectively toxic only to cells that are dependent on Sonic Hedgehog. Cyclopamine’s name comes from how it was discovered: through its teratogenic effects on sheep in Idaho that ate corn lily flowers.

Posted on by Quinn Eastman in Cancer Leave a comment