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Printable Handouts
Navigable Slide Index
- Introduction
- Antimicrobial peptides (AMPs)
- History of the discovery of antimicrobial peptides
- The Nobel prize for physiology or medicine 2011
- Host defense against infection
- Drosophila innate immune pathways
- AMPs come in different forms and shapes
- AMPs and proteins in human airway secretions
- The human defensin family
- Synthesis of alpha-defensins & intracellular action
- Cathelicidins
- Processing of the cathelicidin hCAP-18/LL-37
- Cellular sources of AMPs
- Neutrophil granules
- Neutrophil Extracellular Traps (NET)
- Airway epithelial cell functions in host defense
- Regulation of epithelial production of AMPs
- Results of aberrant expression/activity of AMPs
- Allergic inflammation
- Allergic sensitization impairs host defense
- Air-liquid interface (ALI): epithelial cell cultures
- Increased killing of PAO1 induced by IL4 or IL13
- IL4 & IL13 raise hCAP18/LL-37 & hBD2 expression
- Vitamin D affects AMPs & cytokine expression
- 25(OH)D3 affects cytokine & chemokine release
- IL-13 and 25(OH)D3 affect hCAP18/LL-37 levels
- IL13 affects hBD3 but not hBD2 or 25(OH)D3
- IL-13 increases vit.D activating enzyme CYP27B1
- Exposure of ALI cultures to cigarette smoke
- Cigarette smoke affects expression of AMPs
- AMPs in the airway epithelium
- Local environment regulates AMP activity in lung
- Low pH impairs the activity of AMPs
- Mucus and bacteria: a balancing act
- Mucus & AMPs don’t go well together
- Conclusions
- Thank you
Topics Covered
- Antimicrobial peptides (AMPs) are evolutionary conserved elements of the innate immune system
- AMPs are active against a broad spectrum of pathogens, including multidrug resistant bacteria
- Epithelial expression of AMPs is tightly regulated
- Regulation of epithelial vitamin D metabolism affects expression of AMPs
- AMPs act in a complex working environment, which is markedly altered by disease activity
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Talk Citation
Hiemstra, P.S. (2014, January 5). Antimicrobial peptides in the innate immune system of the lung [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved December 8, 2024, from https://doi.org/10.69645/MCLP9656.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Dr. Pieter S. Hiemstra has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
Antimicrobial peptides in the innate immune system of the lung
Published on January 5, 2014
37 min
A selection of talks on Immunology & Inflammation
Transcript
Please wait while the transcript is being prepared...
0:00
Hello, first I would like to introduce myself.
My name is Pieter Hiemstra, and I'm from the Department of Pulmonology
at the Leiden University Medical Center in Leiden, The Netherlands.
In this talk, which is part of the Henry Stewart Talks Series
Cells of the Innate Immune System,
Henry Stewart talks series cells
and their role in the innate immune system.
In my talk, I will focus on the role of these peptides in the lung.
0:35
but, as you will see
Antimicrobial peptides are an essential element
of the innate immune system and essential for host defense
against infection.
And the dramatic consequences of the interaction of an antimicrobial peptide
with a bacterium is shown in this EM image.
It shows what happens to Pseudomonas bacterium
after it has been exposed for 1½ or 3 hours
to an antimicrobial peptide of the family of the cathelicidins.
And what you can see most prominently after 3 hours
is the appearance of blasts on the outer surface of the bacterium,
indicating membrane injury.
And indeed, when considering the antimicrobial mechanisms
involved in the killing capacity of antimicrobial peptides
towards microorganisms it is known that disruption of membrane integrity
is a very, very essential mechanism.
In addition, for some peptides it has been shown
that there is intracellular activity of peptides after death.
after death. They have been translocated
Various cell types are able to produce antimicrobial peptides,
but it appears that on a quantitative basis
the main cellular sources of antimicrobial peptides
are the neutrophils and the epithelial cells.