BENGALURU: Using fruit flies as models, researchers have unravelled specific signalling pathways in blood cells that help understand wound healing better.
In a new study, they show hydrogen peroxide produced from a wound activates specific signalling pathways in fruit flies’ blood cells, also called hemocytes. The study was carried out by Sveta Chakrabarti, an India Alliance DBT/Wellcome Trust fellow and Sandhya Visweswariah, professor, department of molecular reproduction, development and genetics at IISc.
“Our cells sense invading microbes using specific signatures found in them called microbe-associated molecular patterns. Recognising these signatures activates signalling cascades that trigger specific immune responses. Our body can also detect signatures associated with tissue damage and wounds from its own cells. These signals are called damage-associated molecular patterns,” the researchers said.
Hydrogen peroxide, they say, acts as a DAMP signal to help hemocytes home in on the site of damage and activate wound-healing pathways. Hemocytes help produce more hydrogen peroxide near the wound using an enzyme called DUOX. The researchers found that a water channel called aquaporin helps increase intracellular hydrogen peroxide in blood cells following an injury, which is critical for their activation.
“Another immune pathway called toll pathway was found to be activated upon injury, which protects the flies from subsequent infection by bacteria. This points to a role that the injury has in training the immune response to fight a future potential pathogen,” they added.
The study shows a change in the transcriptome of hemocytes at site of tissue injury, with pronounced activation of the toll signalling pathway. “We find induction of cytokine upd-3 and toll receptor activation occur in response to injury alone, in absence of a pathogen,” the paper reads.