Hope for regrowing nerves

Regrowing nerves is the Holy Grail of scientists concerned with tragedies like paraplegia. Researchers at MIT and elsewhere may have taken a key step toward making a reality of that dream. Critical to the advance is a so-called biomaterial – a substance synthesized in the lab from biological components. Using the short snippets of protein called peptides, which have the ability to assemble themselves into structures, the researchers first created a new biomaterial and then sought to see whether nerve cells would grow on it. The cells grew readily, raising the prospect of using such materials to grow new nerves – and maybe other types of tissues, too. “This material is interesting because we can tailor it to grow virtually every type of cell in the body,” says Shuguang Zhang, associate director of the MIT Center for Biomedical Engineering. In addition to Zhang, Todd Holmes, an NYU faculty member and 1994 Institute graduate, worked on the project, as did Guosong Liu, MIT assistant professor of brain and cognitive sciences.

Fossil findings

The famed “Cambrian Explosion” starting 530 million years ago is usually viewed as marking the stage in evolution when the first precursors to today’s sophisticated animal types appeared. For example, it saw the appearance of organisms with characteristics resembling those of today’s snails, clams and other hard-shelled creatures. But while the ancestors of such marine invertebrates make their appearance in the fossil record during the Cambrian era, those found in the preceding era – called the Ediacaran – generally seem less advanced anatomically, and lacking in links to today’s animal kingdom. New studies by geologists from MIT and elsewhere, though, suggest that some comparatively advanced Ediacaran organisms existed 25 million years before the Cambrian Explosion. Using sophisticated methods to date samples from Russia’s White Sea, the researchers showed that the fossils of some Ediacaran multi-celled organisms, along with tracks of worm-like creatures, are at least 555 million years old. “This extends the appearance of diverse, multicellular life and organisms capable of producing tracks on the sea floor deeper in time,” says MIT’s Mark Martin, a postdoctoral associate in earth, atmospheric and planetary sciences (EAPS). EAPS faculty member Samuel Bowring also worked on the project, as did groups from CalTech and the Paleontological Institute of Moscow.

Insight on metastasis

Cancer rarely kills unless it spreads beyond the original tumor. Now, MIT researchers have found what may be the key trigger for this process, called metastasis. In a probe of cells affected by melanoma, a form of skin cancer, the researchers showed that certain genes which are quiet in normal cells become active in malignant ones. The group then showed that a specific gene, rhoC, may have an especially crucial role in metastasis. “If we overexpress rhoC in poorly metastatic cells, they become highly metastatic,” says Richard Hynes, professor of biology and director of the Center for Cancer Research (CCR). “If we express an inhibitor of rhoC in highly metastatic cells, they show reduced metastasis.” The finding may well open the way for new strategies for slowing cancer’s spread. The discovery was made possible because of advances by the federal Human Genome Project, which has a large center at the MIT-affiliated Whitehead Institute for Biomedical Research. Edwin Clark, formerly in Hynes’ lab and currently with Millennium Predictive Medicine in Cambridge, worked on the studies with the CCR’s director and others.

Monthly relief

Drawing on MIT studies, the federal government has okayed the use of the drug Prozac to treat a severe form of pre-menstrual syndrome. The condition, premenstrual dysphoric disorder (PMDD), is marked by lethargy, appetite changes, insomnia and difficulty concentrating as well as the usual PMS symptoms. In studies dating to the 1970s, Richard Wurtman, professor of brain and cognitive sciences, showed that the mood-altering brain chemical serotonin goes up when we eat carbohydrates. His wife, Institute research scientist Judith Wurtman, later uncovered a serotonin-PMS link. “Women with PMS can gain weight because they overeat carbohydrates, often in conjunction with foods that are high in fat,” says Judith Wurtman. But the Wurtmans also found that agents which block serotonin uptake, like Prozac, can improve premenstrual symptoms. MIT patented Prozac’s use in treating PMDD, and it’s being marketed for that use by Eli Lilly and Co. under the trade name Sarafem.