Stories about: microRNA

Protecting damaged hearts with microRNAs

microRNAs facilitate cardiac regeneration after a heart attack
New work advances the possibility of regenerating cardiac tissue after a heart attack. (PHOTO: ADOBE STOCK)

Once the heart is fully formed, the cells that make up heart muscle, known as cardiomyocytes, have very limited ability to reproduce themselves. After a heart attack, cardiomyocytes die off; unable to make new ones, the heart instead forms scar tissue. Over time, this can set people up for heart failure.

New work published last week in Nature Communications advances the possibility of reviving the heart’s regenerative capacities using microRNAs — small molecules that regulate gene function and are abundant in developing hearts.

In 2013, Da-Zhi Wang, PhD, a cardiology researcher at Boston Children’s Hospital and a professor of pediatrics of Harvard Medical School, identified a family of microRNAs called miR-17-92 that regulates proliferation of cardiomyocytes. In new work, his team shows two family members, miR-19a and miR-19b, to be particularly potent and potentially good candidates for treating heart attack.

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Can breast cancer cells tell each other to metastasize?

Extracellular vesicles exosomes microRNA breast cancer metastasis
Breast cancer cells might be able to give each other the ability to metastasize using microRNAs packaged into extracellular vesicles similar to these exosomes. (Photo: Kourembanas Laboratory, Boston Children's Hospital)

Not all cancer cells are created equal. In fact, to call a cancer a cancer, in the singular, is something of a misnomer. Really, a patient could be said to have cancers, as every tumor is actually a mixture of cells with different mutations and capabilities.

One of those capabilities is the ability to escape the main tumor and spread, or metastasize, to other sites in the body. Not every cancer cell has this ability. But just like bacteria can share the ability to resist antibiotics, at least some cancer cells may be able to share the ability to spread.

According to a study by Judy Lieberman, MD, PhD, of Boston Children’s Hospital’s Program in Cellular and Molecular Medicine, breast cancer cells that can metastasize can tell those that can’t to turn that ability on. That conversation takes place via small pieces of RNA called microRNAs, delivered in microscopic packages called extracellular vesicles.

According to Lieberman, not only do her team’s data give insight into the metastatic process, they might also reveal the first example of cancer cells teaching each other.

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It’s not the stem cells but what’s inside them that matters for babies with lung disease

The molecular equivalent of a message in a bottle could open up the possibility of stem cell-based therapies for newborn lung disease — but without the cells. (aturkus/Flickr)

Three years ago, Stella Kourembanas, MD, and S. Alex Mitsialis, PhD, thought they had a major breakthrough in treating pulmonary hypertension (PH) — dangerously high blood pressure in the pulmonary artery (the vessel that carries blood from the heart to the lungs) — and bronchopulmonary dysplasia (BPD) — a chronic lung disease that can affect babies born prematurely or who were put on a ventilator.

The two diseases are complex and serious, often occur together and are currently incurable.

The solution for PH and BPD, the two researchers from Boston Children’s Division of Newborn Medicine thought, was to protect the babies’ fragile lungs with a kind of stem cell called mesenchymal stem cells (MCSs), which can develop into lung tissue.

Their preclinical studies were pretty conclusive. If they transplanted MSCs in mouse models of BPD and PH, the mice didn’t develop the lung inflammation that triggers the disease.

But the results were a little confusing.

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