Features | Partner Sites | Information | LinkXpress
Sign In
PZ HTL SA
GLOBETECH PUBLISHING LLC
GLOBETECH PUBLISHING LLC

Coating of "Self” Peptides Protects Nanoparticles from Macrophage Destruction

By BiotechDaily International staff writers
Posted on 05 Mar 2013
Image: Diagram of Macrophage Interaction: Macrophages are immune cell “border guards” that have evolved to eat all sorts of foreign microbes, but they also eat many particles that are intended for therapeutics and imaging. A “Minimal peptide ‘Passport’” attached to the particles provides recognition signals so that the particles are not eaten, thus improving delivery to diseased cells in the body (Photo courtesy of Mary Leonard, Biomedical Art & Design, University of Pennsylvania).
Image: Diagram of Macrophage Interaction: Macrophages are immune cell “border guards” that have evolved to eat all sorts of foreign microbes, but they also eat many particles that are intended for therapeutics and imaging. A “Minimal peptide ‘Passport’” attached to the particles provides recognition signals so that the particles are not eaten, thus improving delivery to diseased cells in the body (Photo courtesy of Mary Leonard, Biomedical Art & Design, University of Pennsylvania).
Nanoparticles coated with peptides derived from the human protein CD47 were protected from uptake and destruction by macrophages in a genetically engineered mouse model system.

The membrane protein CD47 is reportedly a "marker of self" in mice that impedes phagocytosis of “self” molecules by signaling through the phagocyte receptor CD172a. CD47, which is found on almost all mammalian cell membranes, binds to the SIRPa macrophage receptor in humans.

Investigators at the University of Pennsylvania (Philadelphia, USA) used computers to design the smallest peptides from human CD47 (hCD47) that could perform the same function. They then synthesized these peptides and attached them to virus-size particles for intravenous injection into mice that had been genetically engineered to express a CD172a variant compatible with hCD47.

Results published in the February 22, 2013, issue of the journal Science revealed that the coating of “self” peptides delayed macrophage-mediated clearance of the nanoparticles, which promoted persistent circulation that enhanced dye and drug delivery to tumors.

"There may be other molecules that help quell the macrophage response," said senior author Dr. Dennis Discher, professor of chemical and biomolecular engineering at the University of Pennsylvania, "but human CD47 is clearly one that says, "Do not eat me. It can be made cleanly in a machine and easily modified during synthesis in order to attach to all sorts of implanted and injected things, with the goal of fooling the body into accepting these things as self."

Related Links:

University of Pennsylvania



comments powered by Disqus

Channels

Drug Discovery

view channel
Image: The nano-cocoon drug delivery system is biocompatible, specifically targets cancer cells, can carry a large drug load, and releases the drugs very quickly once inside the cancer cell. Ligands on the surface of the \"cocoon\" trick cancer cells into consuming it. Enzymes (the “worms\" in this image) inside the cocoon are unleashed once inside the cell, destroying the cocoon and releasing anticancer drugs into the cell (Photo courtesy of Dr. Zhen Gu, North Carolina State University).

Novel Anticancer Drug Delivery System Utilizes DNA-Based Nanocapsules

A novel DNA-based drug delivery system minimizes damage to normal tissues by utilizing the acidic microenvironment inside cancer cells to trigger the directed release of the anticancer drug doxorubicin (DOX).... Read more

Lab Technologies

view channel

Experimental Physicists Find Clues into How Radiotherapy Kills Cancer Cells

A new discovery in experimental physics has implications for a better determination of the process in which radiotherapy destroys cancer cells. Dr. Jason Greenwood from Queen’s University Belfast (Ireland) Center for Plasma Physics collaborated with scientists from Italy and Spain on the work on electrons, and published... Read more

Business

view channel

Interest in Commercial Applications for Proteomics Continues to Grow

Increasing interest in the field of proteomics has led to a series of agreements between private proteomic companies and academic institutions as well as deals between pharmaceutical companies and novel proteomics innovator biotech companies. Proteomics is the study of the structure and function of proteins.... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.