Glaucoma is a neurodegenerative disease that causes vision loss and blindness due to a damaged optic nerve. Unfortunately, there is currently no treatment. In a newly published paper, researchers found neurons use mitochondria for a steady source of energy, and restoring mitochondrial homeostasis in the diseased neurons can protect the optic nerve cells from being damaged.
“The fundamental mechanisms that we discovered can be used to protect neurons in glaucoma and be tested for other diseases. We have identified a critical step of complex mitochondrial homeostasis process, which rejuvenates the dying neuron, similar to giving a lifeline to a dying person” said Arupratan Das, PhD, principal investigator of the study.
The research team, led by Michelle Surma and Kavitha Anbarasu, used induced pluripotent stem cells from patients with and without glaucoma as well as clustered regularly interspaced short palindromic repeats engineered human embryonic stem cells with glaucoma mutation. Researchers identified glaucomatous retinal ganglion cells suffer mitochondrial deficiency with more metabolic burden on each mitochondrion. This leads to mitochondrial damage and degeneration. Mitochondria are the tube-like structures in cells which produce adenosine triphosphate, the cell’s energy source.
However, the process could be reversed by enhancing mitochondrial biogenesis by a pharmacological agent.
“Finding that retinal ganglion cells with glaucoma produce more adenosine triphosphate even with less mitochondria was astonishing,” Das said. “However, when triggered to produce more mitochondria, the adenosine triphosphate production load was distributed among more mitochondria which restored the organelle physiology. It is similar to a situation where a heavy stone is carried by fewer people versus a greater number of people — each person will have less pain and injury, just like each mitochondrion will have less difficulty and damage.”
In the future, Das would like to test if these mechanisms protect the optic nerve in animal models under injury before testing in humans to hopefully lead to new clinical interventions.
Michelle Surma, Kavitha Anbarasu, Sayanta Dutta, Leonardo J. Olivera Perez, Kang-Chieh Huang, Jason S. Meyer, Arupratan Das. Enhanced mitochondrial biogenesis promotes neuroprotection in human pluripotent stem cell derived retinal ganglion cells. Communications Biology, 2023; 6 (1) DOI: 10.1038/s42003-023-04576-w
Indiana University School of Medicine. “Researchers discover therapeutic target to aid in glaucoma treatment.” ScienceDaily. ScienceDaily, 10 March 2023. <www.sciencedaily.com/releases/2023/03/230310103513.htm>.
Photo by Arteum.ro