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Researchers at the ICMR-National Institute of Nutrition, Hyderabad, have reported that exposure to lead disrupts the waste-clearing and recycling machinery of nerve cells, with the damage centred on lysosomes.
The work, published in the Journal of Applied Toxicology, studied human neuronal cells in the laboratory and exposed them to lead and to two forms of amyloid-beta peptide.
Lead alone and amyloid-beta alone each caused some disruption, but the combination had a far stronger effect - lowering cell survival, upsetting the acidic environment lysosomes need to work, and damaging lysosomal structure so the membranes became unstable and leaky.
The team was led by Dr Suresh Challa, Scientist-G and Head of Cell Biology at ICMR-NIN; the institute's director Dr Bharati Kulkarni said the findings underline the need to study how environmental pollutants interact with biological factors affecting brain health.
The researchers stressed that these are laboratory findings in cells and do not establish that environmental lead exposure causes neurodegenerative disease in humans.
A cell continuously generates damaged proteins and worn-out components, and it survives by digesting and recycling them. Lysosomes are the organelles that do this digestion, and they need a strongly acidic interior for their enzymes to work. Nerve cells are unusually dependent on this housekeeping because, unlike skin or gut cells, they are not replaced - a neuron must keep the same interior working for a lifetime. If lysosomes lose their acidity or their membranes turn leaky, two things follow: waste accumulates, and the digestive enzymes escape into the rest of the cell where they do damage of their own. That is the mechanism the ICMR-NIN team reports lead aggravating, and the reason the finding is framed against amyloid-beta, the peptide associated with the protein deposits seen in neurodegenerative disease.
Simple Analogy: Lysosomes are the cell's recycling plant. Lead does not add more garbage - it damages the plant, so waste piles up and the plant's own chemicals start leaking out.
India's premier nutrition research institute, founded in 1918 by Sir Robert McCarrison as the Beri-Beri Enquiry Unit at the Pasteur Institute, Coonoor; it became the Nutrition Research Laboratories in 1929, shifted to Hyderabad in 1958 and was redesignated the National Institute of Nutrition in 1969
The apex body for the formulation, coordination and promotion of biomedical research in India, under the Department of Health Research, Ministry of Health and Family Welfare; NIN is one of its permanent institutes
GS Paper III > Science and Technology > Health and Biotechnology; GS Paper III > Environment > Pollution
General Awareness > General Science, Chemistry and Biology
Consider the following pairs: Commonly used / consumed materials - Unwanted or controversial chemicals likely to be found in them 1. Lipstick - Lead 2. Soft drinks - Brominated vegetable oils 3. Chinese fast food - Monosodium glutamate Which of the pairs given above is/are correctly matched?
Answer: 1, 2 and 3
The membrane-bound organelle that digests damaged proteins and unwanted cellular material, using enzymes that require an acidic interior.
The process by which a cell delivers its own damaged components to lysosomes for degradation and recycling.
A peptide whose aggregation into plaques is associated with the pathological changes seen in neurodegenerative disease.
Lead sulphide (PbS), the principal ore mineral of lead.
Harm caused by metals such as lead, mercury, cadmium and arsenic, which accumulate in the body and disrupt multiple organ systems.