New research uncovers distinct roles for corneal stem cells

How does the cornea maintain its rapid pace of cell turnover—and how does the body regenerate it after injury? A research team led by Pantelis Rompolas, Assistant Professor of Dermatology and Olivia Farrelly, a Ph.D. candidate in the Cell and Molecular Biology Graduate Group, uncovered exciting new clues by identifying separate stem cell pools for maintenance and injury repair.

The investigators used two-photon live imaging in mice to explore the cell dynamics of the corneal limbus, an important adult stem cell niche that maintains the cornea. They find that stem cells display different roles and fates depending on location: cells in the inner limbus primarily maintain the cornea during normal conditions while cells of the outer limbus step in to help regenerate the cornea after injury.

These findings reconcile prior observations in the field regarding how the limbus contributes to eye health and inform ongoing attempts to develop cell therapies for ocular diseases. You can read more about this research in Cell Stem Cell.

Pathway behind muscle breakdowns in Duchenne muscular dystrophy discovered

An overactive genetic pathway in muscle stem cells was found to shorten the ends of chromosomes, called telomeres, resulting in DNA damage that impedes the normal healing response, according to a new study by researchers in the Perelman School of Medicine at the University of Pennsylvania. The researchers believe this finding unveils the body’s origin point for the chronic muscle injuries associated with diseases like Duchenne muscular dystrophy. This work was published today in Cell Reports.

The specific pathway the researchers studied, NF-kB, is tied both to DNA transcription and inflammation response, among other things. It is the first genetic pathway found to directly affect telomere shortening. Shortened telomeres were previously identified as a key feature of patients with Duchenne muscular dystrophy, a severe muscle disease characterized by extensive muscle injury and repair.

Read more about this work from the Mourkioti lab in Penn Medicine News.

The origin of reproductive organs

Early in human development, during the first trimester of gestation, a fetus may have XX or XY chromosomes that indicate its sex. Yet at this stage a mass of cells known as the bipotential gonad that ultimately develops into either ovaries or testes has yet to commit to its final destiny.

While researchers had studied the steps that go into the later stages of this process, little has been known about the precursors of the bipotential gonad. In a new study published in Cell Reports and co-led by Kotaro Sasaki of Penn’s School of Veterinary Medicine, an international team lays out the detailed development of this key facet of sexual determination in two mammalian models.

Read more in Penn Today

Photo credit: Kotaro Sasaki

Bartolomei, Zaret among IRM researchers receiving major honors

The IRM is incredibly proud of our scientists and excited when they receive outside recognition. Recently, several IRM researchers received major award and honors. Congratulations to these remarkable scientists!

Marisa S. Bartolomei, Ph.D Marisa Bartolomei was inducted into the National Academy of Sciences (NAS) as part of its 2021 class. NAS recognized Dr. Bartolomei, who serves as co-Director of the IRM’s Reproductive Medicine program, for her contributions to our understanding of genomic imprinting. She joins 119 other scientists in this year’s class of inductees, a class that includes a record-breaking number of women.
Kenneth S. Zaret IRM Director Ken Zaret has been elected to the American Academy of Arts and Sciences. The country’s founders established the Academy in 1780 to “provide guidance to a young nation that would face challenges and need expertise and excellence to emerge stronger.” Dr. Zaret joins a number of leaders in the sciences, arts, humanities, and other fields as part of this year’s class.
Rajan Jain
The American Society for Clinical Investigation (ASCI) named Rajan Jain as the recipient of the 2021 Donald Seldin~Holly Smith Award for Pioneering Research. Dr. Jain will receive an unrestricted award of $30,000 to advance his academic efforts and will deliver a scientific talk at the 2022 AAP/ASCI/APSA Joint Meeting.
Dennis E. Discher The Biomedical Engineering Society awarded Dennis Discher the 2021 Shu Chien Achievement Award. This Award is bestowed upon an individual who has demonstrated meritorious contributions to the field of cellular and molecular bioengineering.




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