outsmarting the superbug: developing alternatives to antibiotics susan a. mcdowell, ph.d. department...
TRANSCRIPT
![Page 1: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/1.jpg)
Outsmarting the Superbug: developing alternatives to antibiotics
Susan A. McDowell, Ph.D.Department of BiologyBiotechnology ProgramBall State UniversityMuncie, [email protected]
![Page 2: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/2.jpg)
Staphylococcus aureus (staph, MRSA)
Morbidityendocarditis
osteomyelitis
Mortality
most common infectious agent leading to sepsis
1 million sepsis-associated deaths (1999-2005)
![Page 3: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/3.jpg)
Risk factors for virulent S. aureus infections
Hospitalization most common cause of nosocomial cases of pneumonia and surgical wound infection
Invasive procedures hip or knee replacement, catheterization
Immunosuppressionage, HIV
Community exposurecontact sports
![Page 4: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/4.jpg)
Treatment of infectionAntibiotic Mode of Action
Tetracycline Binds to bacterial ribosomes
Quinolones Stop bacterial DNA replication
Penicillin Blocks bacterial cell wall formation
Cephalosporins Block bacterial cell wall formation
Methicillin Blocks bacterial cell wall formation
Vancomycin Blocks bacterial cell wall formation
![Page 5: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/5.jpg)
Mechanisms of antibiotic resistance
Antibiotic
Enzymes that alter antibiotics (chloramphenicol aceyltransferase)
Pumps that transport antibiotics out of the cell
Antibiotic
Enzymes that degrade antibiotics (penicillinase)
Antibiotic
Plasmid with resistance genes
(ampicillin)
Figure adapted from Lisa Melton: http://www.wellcome.ac.uk/doc_WTX026110.html
Chromosomal changes – alter amino acid
sequence/binding site of antibiotic(MRSA – new transpeptidase)
![Page 6: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/6.jpg)
Challenge: Increase in antibiotic resistance
Adapted from Clinical Infectious Diseases, 2006, 42: 389-91
Hea
lthca
re-a
ssoc
iate
d M
RS
A in
fect
ions
(%
)
0
10
20
30
40
50
60
70
1974 1995 2004
![Page 7: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/7.jpg)
Hypothesis
Blocking infection at the level of the host is protective.
![Page 8: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/8.jpg)
How we study host cell invasion
Human umbilical vein endothelial cell (HUVEC)
![Page 9: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/9.jpg)
Host cell
Cell Membrane
![Page 10: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/10.jpg)
Host cell
Cell Membrane
Nucleus
![Page 11: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/11.jpg)
Host cell
Cell MembraneCytoplasm
Nucleus
![Page 12: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/12.jpg)
Host cell
Cell MembraneCytoplasm
Nucleus
Vimentin
![Page 13: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/13.jpg)
Host cell
S. aureus
Cell MembraneCytoplasm
Nucleus Fluorescent secondary antibody binds to protein A of S. aureus
Protein AFc region of IgG
S. aureusATCC#29213
![Page 14: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/14.jpg)
S. aureus
Fibronectin binding protein
Fibronectin
Integrina5b1
Primary mechanism of host invasion
![Page 15: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/15.jpg)
S. aureus
Fibronectin binding protein
Fibronectin
Integrina5b1
![Page 16: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/16.jpg)
S. aureus
Fibronectin binding protein
Fibronectin
Integrina5b1
![Page 17: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/17.jpg)
Our focus – investigate host cell responses that facilitate invasion and could be blocked pharmacologically
![Page 18: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/18.jpg)
Uninfected Infected (1 hr)
The first host cell response we noticed: Actin stress fibers
disassemble during invasion by S. aureus – WHY?
![Page 19: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/19.jpg)
The second host cell response we noticed: Filopodia
formation (a different actin structure) is stimulated during
S. aureus invasion
Stankiewicz, et al., BBRC 391: 2010
Is this assembly of filopodia related to the disassembly of actin?
![Page 20: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/20.jpg)
What we found: When CDC42, a known regulator of actin,
is mutated, host cell invasion is inhibited
HEK CDC42 C507V/V5
Inte
rnal
ized
bac
teria
(%
Con
trol
+/-
SE
M)
*20
40
60
80
100
120
Horn, et al., JPET 326: 2008 *less than control; p < 0.05 Student’s t-test
![Page 21: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/21.jpg)
ML 141 (recently identified inhibitor of CDC41)
**
Derivatives of ML 141
Could a compound that blocks CDC42 activity inhibit invasion?
Could we improve upon that compound?
![Page 22: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/22.jpg)
ML 141
More derivatives of ML 141
![Page 23: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/23.jpg)
Is the inhibition of CDC42 limiting stress fiber disassembly?
![Page 24: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/24.jpg)
Do the derivative compounds work?
RSM 06
![Page 25: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/25.jpg)
Potential Outcomes
We will identify a compound with greater efficacy in inhibition of invasion.
Alternatively, several compounds of similar efficacy as that of ML 141 will be identified in vitro that may demonstrate greater bioavailability in vivo.
![Page 26: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/26.jpg)
Significance
Addressing questions of basic science
how S. aureus is internalized
how infection spreads
Evaluation of the therapeutic benefit of inhibitors
during systemic infection
as a prophylactic for invasive procedures
![Page 27: Outsmarting the Superbug: developing alternatives to antibiotics Susan A. McDowell, Ph.D. Department of Biology Biotechnology Program Ball State University](https://reader030.vdocument.in/reader030/viewer/2022032707/56649e155503460f94afe9e1/html5/thumbnails/27.jpg)
AcknowledgementsThe N
ational
Institutes
of Health
Der
ron
Bis
hop
Fran Rushing
John
McK
illip
Sharm Knecht
Kelly Gammon
Chr
is V
laho
sJulie Clark (Birdsong)Charron Johnson
Mary Horn
Terri AbrahamCatherine Volk
Laur
a M
icha
el
Parker Siddall
Kelsey HaaningAmy Pierce (Brown)
Jacy WillisRay Kenney
Indiana
Academy o
f
Science
Lilly V
Sarita Tony
Xiaoling Liu
Tiera Liby
Kristin Abel
Amanda Reese
Dan Horan
Sponsore
d Pro
grams
OfficeHonors
College
Tom
Kirc
hhau
sen
Hea
ther
Bru
ns
Janelle Owens
Daniel PetrovichTraci Stankiewicz
Alys Jordan
Nickie MayRobin DeWalt
Ashley Zahrt
Jacob Henry
Shana Ellis
Amber Hampton
Julie Pratt
Jim
Mitc
hell
Larr
y S
klar
Geo
rge
Tego
sM
ark
Hay
nes
College of S
cience
s and H
umanities
Katie Reed
Diana Santana
Lindy Caffo
Rob
Sam
mel
son