Next-gen therapy. AMP up the fight against hardy pathogens

Subject : Science and Technology

Context:

Scientists are using a little-known line of defence — antimicrobial peptides — to beat antimicrobial drug resistance.

The problem of drug-resistant microbes:

Our bodies have their own defence mechanism against invading microbes (pathogens such as bacteria and viruses).
This defence mechanism is in the form of antibodies, which are proteins (long chains of amino acids)- the antibodies destroy the pathogens, or, at least, most of the time.
This defence mechanism is strengthened by man-made drugs- antibiotics– which kill bacteria (not viruses).
Over time, these microbes develop resistance to drugs.
This antimicrobial drug resistance (ADR) is now so serious that it has come to be recognised as a major killer.

Solution: Antimicrobial peptides or AMPs:

Scientists are now turning to a less-recognised line of defence known as ‘antimicrobial peptides’, or AMPs.
Peptides are small chains of amino acids.
AMPs are produced by human bodies, as also other living beings.
Today, about 5,000 AMPs are known, catalogued.
AMPs are proving to be smarter than invading pathogens.
These peptides are effective, broad-spectrum antimicrobials that establish themselves as new therapeutic agents, and hold the potential to kill gram-negative and gram-positive bacteria, fungi, enclosed viruses, and even mutated or malignant cells.
Unlike antibiotics, AMPs are effective against viruses too.

How do AMPs work?

The pathogens enter healthy cells and use the chemicals to multiply, destroying the cells in the process.
AMPs attach themselves to cell membranes of bacteria or virus and prevent them from entering healthy cells.
This happens because the cell walls of pathogens are negatively charged, whereas AMPs are positively charged — the attraction between unlike charges enables AMPs to cling to the membranes.

The issue with AMPs:

The problem is, how to produce AMPs.
It is possible to chemically synthesise AMPs. Another option is to take the DNA in organisms and coax it to produce the peptides.
But both are time-consuming, costly and with no guaranteed output.

Designers’ AMPs:

Scientists have evolved a novel method called the ‘cell-free protein synthesis’ (CFPS), which involves in-vitro transcription (making RNA from DNA) and translation (making peptides from RNA). In other words, the peptides are made outside living cells.
This method can help overcome potential cellular toxicity effects and open up the way for rapid, small-scale production of several hundreds of peptides from linear DNA in parallel.

Scope of AMPs:

There is no AMP drug in the market yet.
In 2019, the Indian Institute of Science, Bengaluru, and MS Ramaiah Medical College came up with a peptide, named Omega76, against the ESKAPE family of bacteria, but there has not been much progress since.