May 25, 2022 - Podcast

Episode 272 — Zinc deficiency, and pollution

Zinc plays a critical role in our bodies, with one-tenth of the proteins in our cells requiring it for normal functions. But up to 30 percent of people in some parts of the world are at risk of zinc deficiency, which can cause slowed growth, impaired immune function, neurological disorders and cancers. It isn’t clear how zinc gets into the proteins that use it or how our cells respond to zinc deficiency, but a team led by researchers from Indiana University and Vanderbilt University Medical Center has described and characterized the first zinc metallochaperone: a protein that puts zinc into other proteins. Metallochaperones guide metal nutrients to high-priority targets and are put to work by the cell when there is not enough zinc to go around, says David Giedroc, a distinguished professor of chemistry at IU. The zinc metallochaperone has been named ZNG1, and the researchers think it may be one of the most important regulatory strategies for helping humans cope with severe zinc starvation. The researchers believe when the body is starved of zinc, ZNG1 steps in to ensure that zinc is delivered to the most important zinc-containing proteins. One of these proteins plays an essential role in making other proteins in the cell. This discovery opens up an entirely new area of biology for exploration, in which regulatory factors like ZNG1 control a number of different processes through metal insertion, they say.

In other news, pollution was found to be responsible for nine million deaths in 2019, according to a recent study published in the Lancet Planetary Health Report, and more than 90 percent of pollution’s impact is felt in low- and middle-income countries. Although researchers have seen decreases in the number of deaths from pollution sources associated with extreme poverty, such as indoor air pollution and water pollution, these reductions are offset by increased deaths attributable to industrial pollution, such as ambient air pollution and chemical pollution. Joseph Shaw, an associate professor at IU and expert in chemical pollution, contributed to the report and is helping develop precision toxicology approaches as part of a consortium of U.S. and European organizations called Precision Tox. Such approaches can help reduce deaths from modern pollution by improving methods for identifying and mapping toxic chemicals in the environment. The world needs solutions that take into account the way the various sources of pollution make an impact on the health of humans around the world, or else gains in one area will continue to be offset by tragedies in others, Shaw says. Besides the death toll attributed to pollution in 2019, the report found that deaths caused by modern forms of pollution, such as ambient air pollution and toxic chemical pollution, have increased 66 percent since 2015 and have been driven by industrialization, uncontrolled urbanization, population growth, fossil fuel combustion and an absence of adequate national or international chemical pollution policies. Most countries worldwide have done little to deal with the issue of modern pollution, but efforts to improve conditions can make a positive impact, they say. The Precision Tox tools Shaw and other IU researchers are developing provide an emerging approach to tackle the injustices of modern chemical pollution and provide health protection, especially in low- and middle-income countries, Shaw says. Precision Tox will help establish causation between chemicals and their adverse health effects, and between polluters and the victims of pollution, which will reduce the burden of pollution by vastly improving opportunities for effective recourse.