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Exposure to lead can cause epigenetic changes even at relatively low levels

Publicado em 17 maio 2021

A group of Brazilian and Portuguese researchers regulate the presence of lead in an organism and DNA methylation, a physiological process required to control gene expression and ensure that genes function properly. We observed a correlation with microRNAs (miRNAs) that may be involved in the mechanism.

Changes were seen in the blood cells of workers in lead-based automotive battery factories. Curiously, the lead levels of blood samples from 85 volunteers (average 20 micrograms (20 µg / dl) per deciliter of blood) are above the permissible upper limit (60 µg / dl) defined by Brazilian law. It was low.

This study is supported by FAPESP Frontier of genetics.. The author is affiliated with the Federal University of Sao Paulo (UNIFESP), the Federal University of ABC (UFABC), the University of Morumbi, Anhenbi, the University of Sao Paulo (USP) in Brazil, and the New University of Lisbon (UNL). In Portugal. This study was part of a project funded by FAPESP.

“All studies conducted so far suggest that, although early, low levels of lead exposure are not necessarily associated with a lack of adverse effects and are well established in the literature. It is possible that it correlates with molecular events that precede the event being done, as it stems from chronic lead poisoning, such as neurological and hematological problems, “said the end of this article. The author, Gustavo Rafael Mazzaron Barcelos, said. Barcelos is a professor at the UNIFESP Institute for Health and Social Studies (ISS) in Santos, Sao Paulo.

Low doses did not directly correlate with health problems, but DNA changes should serve as a warning, he added. “These levels are not safe. It would be great if we could minimize lead exposure levels, but the entire industrial system depends on lead production. Systematically observed in Brazil We need good public policy to minimize our exposure. Decades. “

In Brazil, lead exposure above 60 µg / dl should be reported to SUS, the National Health Service, and social security authorities. In China, studies show that local workers have high blood lead levels, averaging about 40 µg / dl.

“We analyzed DNA methylation, one of the epigenetic changes that occur primarily in the promoter regions that control gene function. When methylation causes these changes in these regions, protein synthesis is dysregulated. There is evidence that lead exposure can inhibit DMNT1. Promoters involved in the regulation of DNA methylation. In the samples analyzed, the DMNT1 gene is targeted. The miRNA, miR-148a, was abundantly found, “said Marilia Ladeirade Araújo, the first author of the article. This study was part of her PhD. Research on the ISS-UNIFESP. She received a scholarship from FAPESP and performed part of her analysis while working as a research intern at UNL School of Medicine.


Previous studies have detected an overall reduction in DNA methylation in the same worker cohort using samples taken at a factory in Paraná.Reported in Journal of Toxicology and Environmental Health, Part A, This study was part of Paula Pícoli Devóz’s master’s study at the Ribeirao Preto Pharmaceutical School (FCFRP-USP) at the University of Sao Paulo. Devóz is also a co-author of the latest published research.

The researchers then decided to identify some miRNAs that might be associated with this event and look for biomarkers of decreased DNA methylation. They observed a significant increase in miR-148a. It has been described in the literature as being associated with DNA damage, inflammatory processes, and oxidative stress. All of these may correlate with the development of multifactorial lesions, such as neurodegenerative diseases and cancer.

“The advantage of using miR-148a as a biomarker for epigenetic disorders induced by lead exposure is that these changes in its expression may precede various cellular disorders such as oxidative stress and cell death. That’s what Barcelos said. “We still don’t know if the reduction in DNA methylation will have a negative effect. We analyzed the overall state of this parameter across the DNA and found it to be a potential biomarker for this state. “

As soon as the pandemic was over, he continued his research by collecting more samples from the same cohort for a relatively long period of time, whether the effects of low levels of exposure persisted, and how the organism would do it. I will check if it can be applied.

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For more information:

Marília Ladeirade Araújo et al, Association of miR-148a with DNA methylation profile in individuals exposed to lead (Pb), Frontier of genetics (2021). DOI: 10.3389 / fgene.2021.620744

Quote: Lead exposure is also at relatively low levels (May 17, 2021) obtained from on May 17, 2021. Can cause epigenetic changes

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Exposure to lead can cause epigenetic changes even at relatively low levels

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