Category: Uncategorized

In summary

Peptide therapeutics are small chains of amino acids (basically mini proteins) that can be used to treat diseases. They’re made of the same monomer (amino acid) as proteins, but proteins are much larger polymers than peptide drugs. The body naturally creates peptides for a bunch of different functions, so its a versatile way to create drugs whose presence creates signals for cell processes.

In depth

Hello and welcome back! After a very busy month and a half, let’s talk about peptide therapeutics.

In Boston, I see a ton of peptide therapeutic start ups popping up, but the actual peptide modality has been around for quite a while. Insulin is probably one of the most recognizable therapeutic peptides available on the market, but other commercially available, therapeutic peptides are used to treat bowel diseases, hereditary angioedema, and even HIV treatment. In terms of therapeutic modality sizing, peptides are the intermediate between small molecules (oligonucleotides) and large molecules (proteins). They’re made of the same monomer (amino acid) as proteins, but they’re a different class of medicine, because proteins are much larger polymers (thousands of amino acids) than peptide drugs (usually less than 100 amino acids). Check out the diagram below from a peptide manufacturer:

To understand how therapeutic peptides work, we need to go into a little bit about cell signaling. I like to think about cells like little radio towers, constantly transmitting and accepting signals to others towers. In one of the best understood cases, cells send chemical messages called ligands to other cells, and the cell that receives this message uses one of its hundreds of specialized receptors. Each cell type (such as pancreatic cells, neurons, and liver cells) has different kinds of receptors, because each message is designed to insight a different cellular response! So, in many cases, therapeutic peptides can act as these ligands that cue a certain cell type to perform a specific function.

Now, therapeutic peptides don’t exactly classify as gene therapy, and let me explain why. When we talked about ASOs and siRNA, we had modalities that were directly involved in gene regulation by say repressing translation. However, these therapeutic peptides aren’t exactly working within the central dogma–they don’t directly interfere with the DNA or RNA processes we think of with traditional gene therapy. I like to think of therapeutic peptides working more in parallel to gene therapy, because it’s helping the cell to insight a favorable response by exposing the cell to these artificial signals. For example, a study in the Journal of Medical Endocrinology found that the adrenocorticotropic hormone therapeutic peptide has been shown to regulate gene expression in adrenal cells. It’s not quite working on the DNA and RNA aspect of gene regulation, but it’s working in parallel on the cell side.

In literature