A new therapy changes the balance of osteoblasts (pictured here) and fat cells in the bone marrow, leading to stronger bones.

Science Picture Co/Science Source

By Emma YasinskiSep. 5, 2017 , 2:59 PM

A drug that can reverse diabetes and obesity in mice may have an unexpected benefit: strengthening bones. Experiments with a compound called TNP (2,4,6-trinitrophenol, which is also known as picric acid), which researchers often use to study obesity and diabetes, show that in mice the therapy can promote the formation of new bone. Thats in contrast to many diabetes drugs currently in wide use that leave patients bones weaker. If TNP has similar effects in humans, it may even be able to stimulate bone growth after fractures or prevent bone loss due to aging or disuse.

As more and more patients successfully manage diabetes with drugs that increase their insulin sensitivity, doctors and researchers have observed a serious problem: Thedrugs seem to decrease the activity of cells that produce bone, leaving patients prone to fractures and osteoporosis.

There are millions and millions of people that have osteoporosis [with or without diabetes], and it's not something we can cure, says Sean Morrison, a stem cell researcher at University of Texas Southwestern in Dallas. We need new agents that promote bone formation.

Morrison and his colleagues have shown that a high-fat diet causes mice to develop bones that contain more fat and less bone. The diet increased the levels of leptina hormone produced by fat cells that usually signals satiety in the brainin the bone marrow, which promoted the development of fat cells instead of bone cells. That suggests that nutrition has a direct effect on the balance of bone and fat in the bone marrow.

After reading Morrisons work, Siddaraju Boregowda, a stem cell researcher at the Scripps Research Institute in Jupiter, Florida, was reminded of genetically altered mice that dont gain body fat or develop diabetes, even when fed high-fat diets. He and his boss, stem cell researcher Donald Phinney, wondered whetherthose mice were also protected from the fattening of the bone marrow that accompanies a high-fat diet.

They contacted Anutosh Chakraborty, a molecular biologist who was studying such mice down the hall at Scripps at the time. The animals lack the gene for an enzyme called inositol hexakisphosphate kinase 1 (IP6K1), which is known to play a role in fat accumulation and insulin sensitivity. The scientists suspected that the lost enzyme might affect the animals' mesenchymal stem cells (MSCs)stem cells found in the bone marrow that are capable of developing into both thebone cells and fat cells that make up our skeletons. If too many fat cells develop, they take the place of bone cells, weakening the bone.

The researchers fed genetically altered and normal mice a high-fat diet for 8weeks. Not only did the genetically altered mice develop fewer fat cells than their normal counterparts, but their production of bone cells was higher than that of the normal mice, the team reported last month in Stem Cells.

The scientists then set out to see whetherthey could use a drug to achieve the same effect in normal mice. For 8weeks, they fed normal mice a high-fat diet and gave them daily injections of either TNP, a well-known IP6K1 inhibitor, or a placebo. When they analyzed the animals bones and marrow, they found that mice that had received TNP had significantly more bone cells, fewer fat cells, and greater overall bone area. The IP6K1 inhibitor apparently protected the mice from the detrimental effects of the high-fat diet.

The study provided thesurprising result that one new therapy currently being explored to lower insulin resistance promotes, rather than decreases, the formation of bone in mice, says DarwinProckop,a stem cell researcher at Texas A&M College of Medicine in Temple, who was not involved in the work.

The researchers still need to figure out how to deliver TNPs effects only to MSCs, instead of the entire body, given that it sometimes blocks other enzymes along with IP6K1. Inhibition of IP6K1 is a promising target for patients with both diabetes and obesity, Boregowda says. He says he and his colleagues are now enthusiastic about testing their findings in a wide range of bone-related diseases and disorders. It might even help heal broken bones, he speculates.

Phinney, on the other hand, is aiming even higher. He wonders whetherthe therapy could also be useful for space travel, because bones are especially vulnerable to deterioration in zero gravity. Its a whole new field of science and drug discovery.

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New therapy could protect diabetic bones - Science Magazine

In developing fetuses, infection by the Zika virus can result in devastating neurological damage, most notably microcephaly and other brain malformations. In a new study, published today in The Journal of Experimental Medicine, researchers at the University of California San Diego School of Medicine and Washington University School of Medicine in St. Louis report the virus specifically targets and kills brain cancer stem cells.

The findings suggest the lethal power of the virus notorious for causing infected babies to be born with under-sized, misshapen heads could be directed at malignant cells in adult brains. Doing so might potentially improve survival rates for patients diagnosed with glioblastomas, the most common and aggressive form of brain cancer, with a median survival rate of just over 14 months after diagnosis.

The Zika virus specifically targets neuroprogenitor cells in fetal and adult brains. Our research shows it also selectively targets and kills cancer stem cells, which tend to be resistant to standard treatments and a big reason why glioblastomas recur after surgery and result in shorter patient survival rates, said Jeremy Rich, MD, professor of medicine at UC San Diego School of Medicine. Rich is co-senior author of the study with Michael S. Diamond, MD, PhD, professor, and Milan G. Chheda, MD, assistant professor, both at Washington University School of Medicine in St. Louis.

Transmission electron microscope image of negative-stained, Fortaleza-strain Zika virus (red), isolated from a microcephaly case in Brazil. Image courtesy of NIAID.

This year, more than 12,000 Americans will be diagnosed with glioblastomas, according to the American Brain Tumor Association. Among them: U.S. Senator John McCain, who announced his diagnosis in July. They are highly malignant. The two-year survival rate is 30 percent.

Standard treatment is aggressive: surgery, followed by chemotherapy and radiation. Yet most tumors recur within six months, fueled by a small population of glioblastoma stem cells that resist and survive treatment, continuing to divide and produce new tumor cells to replace those killed by cancer drugs.

For Zhe Zhu, MD, PhD, a postdoctoral scholar in Richs lab and first author of the study, the hyper-reproductive capabilities of glioblastoma stem cells reminded him of neuroprogenitor cells, which fuel the explosive growth of developing brains. Zika virus specifically targets and kills neuroprogenitor cells.

So Zhu, with Rich, Diamond, Chheda and other collaborators, investigated whether the Zika virus might also target and kill cultured glioblastoma stem cells derived from patients being treated for the disease. They infected cultured tumors with one of two strains of the virus. Both strains spread through the tumors, infecting and killing stem cells while largely avoiding other tumor cells.

The findings, the authors said, suggest that chemotherapy-radiation treatment and a Zika infection appear to produce complementary results. Standard treatment kills most tumor cells but typically leaves stem cells intact. The Zika virus attacks stem cells but bypasses ordinary tumor cells.

We see Zika one day being used in combination with current therapies to eradicate the whole tumor, said Chheda, an assistant professor of medicine and of neurology at Washington University School of Medicine.

To find out whether the virus could boost treatment efficacy in a live animal, researchers injected either the Zika virus or a saltwater placebo directly into glioblastoma tumors in 18 and 15 mice, respectively. Two weeks after injection, tumors were significantly smaller in the Zika-treated mice, who survived significantly longer than those given the placebo.

The scientists note that the idea of injecting a virus notorious for causing brain damage into patients brains seems alarming, but they say Zika may prove a safe therapy with further testing because its primary target neuroprogenitor cells are rare in adult brains. The opposite is true of fetal brains, which is part of the reason why a Zika infection before birth produces widespread and severe brain damage while a normal Zika infection in adults typically causes mild symptoms or none at all.

The researchers also conducted studies of the virus using brain tissue from epilepsy patients that showed the virus does not infect non-cancerous brain cells.

As an additional safety feature, the research team introduced two mutations that weakened the viruss ability to combat natural cellular defenses against infection, reasoning that while the mutated virus would still be able to grow in tumor cells, which have a poor anti-viral defense system, it would be quickly eliminated in healthy cells with a robust anti-viral response.

When they tested the mutated viral strain and the original parental strain in glioblastoma stem cells, they found that the original strain was more potent, but that the mutant strain also succeeded in killing the cancerous cells.

Were going to introduce additional mutations to sensitize the virus even more to the innate immune response and prevent the infection from spreading, said Diamond, a professor of molecular microbiology, pathology and immunology. Once we add a couple more, I think its going to be impossible for the virus to overcome them and cause disease.

Co-authors of the study include: Matthew Gorman, Estefania Fernandez, Lisa McKenzie, Jiani Chai, Justin M. Richner, and Rong Zhang, Washington University, St. Louis; Christopher Hubert, and Briana Prager, Cleveland Clinic; Chao Shan, and Pei-Yong Shi, University of Texas Medical Branch; and Xiuxing Wang, UC San Diego.

Funding for this research came, in part, from the National Institutes of Health (R01 AI073755, R01 AI104972, CA197718, CA154130, CA169117, CA171652, NS087913, NS089272), the Pardee Foundation, the Concern Foundation, the Cancer Research Foundation and the McDonnell Center for Cellular and Molecular Neurobiology of Washington University.

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Zika Virus Targets and Kills Brain Cancer Stem Cells - UC San Diego Health