A new study reveals that two enzymes help immune cells deploy pathogen-killing traps by unraveling and using the chromatin (DNA and its associated proteins) contained in the cells' nuclei to form defensive webs. The study appears online on Oct. 25 in the Journal of Cell Biology.
Neutrophils, the most common type of white blood cells, are difficult to study because they live for only about six hours. So Arturo Zychlinsky and colleagues, from the Max Planck Institute for Infection Biology in Berlin, created a cell-free system that includes neutrophil nuclei and dollops of cytoplasm from the cells. They found that two enzymes stashed in cytoplasmic granules enter the nucleus and join forces to unwind the chromatin and form neutrophil extracellular traps (NETs), webs of chromatin that catch and kill pathogens. The first to make the move is neutrophil elastase (NE), which promotes chromosome decondensation by breaking down two "histone" proteins that help keep chromatin tightly packaged in the nucleus. Later in the process, myeloperoxidase (MPO) arrives at the nucleus to help NE unravel the chromatin. Exactly how MPO performs its task remains unclear, as its catalytic activity isn't required to decondense chromatin.
The researchers confirmed NE's importance for NET formation by exposing mice to Klebsiella pneumoniae bacteria. Neutrophils hustled to the lungs in control mice and in animals lacking NE. But neutrophils from the mice missing NE couldn't produce NETs to snare the bugs.
An important question to answer now, the researchers say, is how NE and MPO travel to the nucleus. The granules could merge with the nuclear membrane directly or burst and free the enzymes into the cytoplasm, from where they subsequently move to the nucleus.
Reference: Papayannopoulos, V., et al. 2010. J. Cell Biol. doi:10.1083/jcb.201006052.
Dear Helpdesk: Working in a Toxic Health Care Environment
March 28th 2024Dear Helpdesk is your steadfast companion, offering life coaching and workplace advice from 2 seasoned IPs for some of your most challenging real-life situations. Let us help you navigate the intersection between work and life, guiding you to navigate the dynamic world of infection prevention with confidence and grace. This article is on handling a toxic health care environment.
Product Locator: Spring and Early Mother's Day Gift Guide for Infection Prevention Personnel
March 27th 2024Whether it's a spring holiday, birthdays, or no reason at all, infection prevention personnel love to give and receive gifts that help at the end of a stressful day. Infection Control Today® offers some gift ideas for infection prevention personnel and their families.
Catching Up With Vangie Dennis, AORN 2022-2023 President at AORN 2024
March 26th 2024Infection Control Today (ICT) had the privilege of catching up with Vangie Dennis, MSN, RN, CNOR, CMLSO, at the Association of periOperative Registered Nurses' (AORN’s) International Surgical Conference & Expo 2024. As the former president of AORN and an esteemed figure in perioperative services, Vangie Dennis shared insights into her recent endeavors and the exciting new chapter she's embarked upon.
How To Optimize Your Time Management Strategies for the Busy Infection Preventionist
March 25th 2024Is your calendar resembling a chaotic masterpiece of overlapping tasks? Join the club of infection preventionists striving to balance responsibilities. Dive into proven strategies from a fellow infection preventionist to reclaim control of your time, streamline tasks, and boost productivity effectively. This is an IP Lifeline article.