SHAPE Society

1. Editorial Slides
VP Watch - May 15, 2002 - Volume 2, Issue 19
PTX3 or CRP?
PTX3; A New Kid on the Atherosclerosis Block!

2.  Osmand et al. in 1977 found that CRP is composed of
five subunits arranged in cyclic symmetry. This
structure was similar to that reported for both C1t
(complement component C1) and amyloid P. They
proposed the term Pentraxin to describe these
homologous proteins as a a subclass of acute phase
proteins. 1
 Pentraxin-3 (PTX3) is a newly discovered marker of
the acute phase response from Pentraxin family.
Pentraxin; Cyclic Pentametric Structure

3.  In 1993, Mantovani, Breviario, and others cloned PTX-3 gene
form IL-1β treated human umbilical vein endothelial cells
(HUVEC). PTX3 gene has been localized on human
chromosome 3. 2,3
 The PTX3 mRNA is induced in endothelial, hepatic, and
fibroblastic cells by IL-1β and TNF-α but not by IL-6 and
interferon-γ.3
 Alles, Mantovani, and colleagues found that PTX3, unlike the
classical Pentraxins CRP and serum amyloid P, is expressed
and released by cells of monocyte-macrophage lineage
exposed to inflammatory signals (extrahepatic expression). 4
PTX3 Unlike CRP Is Extrahepatic

4.  In vivo, the PTX3 gene is most prominently induced in
mouse heart and skeletal muscle. 8
In other study Luchetti et al. by using immunoenzymatic
assay, detected increased levels of PTX3 in synovial fluids
from patients with rheumatoid arthritis.5
 Other long pentraxins, such as murine or rat neuronal
pentraxin-1 and human neuronal pentraxin 2, are
expressed in the central nervous system.
 Intracerebroventricular, but not intravenous, injection of
LPS induces high levels of PTX3 mRNA in the mouse
brain. 6
Pentraxin In Other Diseases

5.  Expression of PTX3 binding sites occurs
late in apoptotic process. PTX3 binding
inhibits recognition of apoptotic cells by
dendritic cells. Human dendritic cells fail
to internalize dying cells in the presence
of PTX3, while they take up normally
soluble or inert particulate substrates. 8
Pentraxin and Apoptosis

6. • Peri, Latini, and colleagues showed that PTX3 (long
Pentraxin) peaked rapidly in patients with MI symptoms
after admission to the hospital and preceded the
increase of CRP (short Pentraxin).
• PTX3 which is present in normal and hypertrophied
human cardiomyocytes, is increased in the blood of
patients with acute MI, and disappears from necrotic
myocytes. PTX3 increases in the blood of patients with
acute MI because it is released from dying or necrotic
cells. 7
PTX3 in MI

7.  As reported in VP Watch of this week,
Hansson et al. recently showed that
immunohistochemical staining of advanced
atherosclerotic plaques revealed strong
expression of PTX3. In contrast, no PTX3
expression was observed in nonatherosclerotic
internal mammary arteries.
 They found that staining serial sections with
cell type– and PTX3-specific antibodies, we
observed that PTX3 was produced principally
by macrophages and endothelial cells.
Infrequent expression by smooth muscle cells
was also observed. 9

8. Also Napoleone, Lorenzet, and colleagues
found that PTX3 increases tissue factor (TF)
expression in HUVECs exposed to other
inflammatory mediators like LPS, IL-1ß, and
TNF-α. 10
 Increasing TF mRNA determined by PTX3
originated from an enhanced nuclear binding
activity of transacting factor.

9. TF Activity in HUVECs Exposed to Different
Concentrations of PTX3
0
50
100
150
200
250
0 1 5 10
LPS
IL-1beta
TNF-alpha
TF activity in HUVECs exposed to different concentrations of PTX3. HUVECs were incubated with
LPS (1 µg/mL), IL-1ß (10 ng/mL), or TNF- (10 ng/mL) in the presence of different amounts of
PTX3. Treatment conditions were as outlined in the legend of Figure 1. The data represent the
mean±SEM of 3 duplicate experiments. For each agonist, *P<0.05 vs sample without PTX3.
Emanuela Napoleone, Angelomaria Di Santo, Antonio Bastone, Giuseppe Peri, Alberto Mantovani, Giovanni de Gaetano, Maria Benedetta
Donati, and Roberto Lorenzet Long Pentraxin PTX3 Upregulates Tissue Factor Expression in Human Endothelial Cells: A Novel Link
Between Vascular Inflammation and Clotting Activation ;Arterioscler Thromb Vasc Biol 2002 22: 782 - 787
TF activity,
U/well
PTX3,μg/ml

10. Effect of PTX3 on IκBα Degradation in
Stimulated HUVECs
P
TX
3LP
S
LP
S
+PTX
3IL-1beta
IL-1beta+P
TX
3
TN
F-alpha
TN
F-alpha+P
TX
3
0
10
20
30
40
50
60
70
80
90
100
PTX3 IL-1beta TNF-
alpha+PTX3
PTX3 LPS LPS+PTX3 IL-1beta IL-1beta+PTX3 TNF-alpha TNF-alpha+PTX3
Effect of PTX3 on I B degradation in stimulated HUVECs. HUVECs were incubated with LPS (1 µg/mL), IL-1ß (10
ng/mL), or TNF- (10 ng/mL) with or without PTX3 (5 µg/mL) for 5 minutes at 37°C. Proteins were extracted, and I
B was determined by Western blotting. The blots were scanned and quantified in AUs with NIH Image software,
version 1.62. Data are the mean±SEM of 3 separate experiments. The unit calculated for the band obtained from
the control cells was assigned a 100% value. In the inset, a representative Western blot is shown.
Emanuela Napoleone, Angelomaria Di Santo, Antonio Bastone, Giuseppe Peri, Alberto Mantovani, Giovanni de Gaetano, Maria Benedetta Donati, and
Roberto Lorenzet Long Pentraxin PTX3 Upregulates Tissue Factor Expression in Human Endothelial Cells: A Novel Link Between Vascular
Inflammation and Clotting Activation ;Arterioscler Thromb Vasc Biol 2002 22: 782 - 787

11. Conclusion
 These observations and the presence
of PTX3 during the early phases of
inflammation offer the biological
plausibility for a role of PTX3 in
atherosclerosis (plaque inflammation,
apoptosis, and thrombosis).
 Because of its extrahepatic source,
PTX3 may be superior to CRP.

12. Questions:
• What are the major sources of PTX3 in
the body?
• Knowing hepatic production of CRP
makes it a nonspecific marker, can
PTX3 (solely extrahepatic) offer a major
advantage over CRP for detection of
plaque inflammation?

13. Questions:
• Is high PTX3 blood level in patients with
MI released by myocardial injury or
atherosclerotic plaques (cause or
effect)?
• Increased tissue factor activity and
reduced uptake of apoptotic bodies
caused by PTX3 makes it a culprit for
plaque vulnerability, does this mean that
PTX3 can be a target for therapy and
plaque stabilization?

14. 1) Osmand AP, Friedenson B, Gewurz H, Painter RH, Hofmann T, Shelton E.; Characterization of C-reactive protein and the
complement subcomponent C1t as homologous proteins displaying cyclic pentameric symmetry (pentraxins). Proc Natl Acad Sci U S
A. 1977 Feb;74(2):739-43.
2) Introna M, Breviario F, d'Aniello EM, Golay J, Dejana E, Mantovani A. ; IL-1 inducible genes in human umbilical vein endothelial cells.;
Eur Heart J. 1993 Dec;14 Suppl K:78-81.
3) Breviario F, d'Aniello EM, Golay J, Peri G, Bottazzi B, Bairoch A, Saccone S, Marzella R, Predazzi V, Rocchi M, et al. ; Interleukin-1-
inducible genes in endothelial cells. Cloning of a new gene related to C-reactive protein and serum amyloid P component. ; J Biol
Chem. 1992 Nov 5;267(31):22190-7.
4) VV Alles, B Bottazzi, G Peri, J Golay, M Introna, and A Mantovani; Inducible expression of PTX3, a new member of the pentraxin
family, in human mononuclear phagocytes Blood 84: 3483-3493
5) Luchetti MM, Piccinini G, Mantovani A, Peri G, Matteucci C, Pomponio G, Fratini M, Fraticelli P, Sambo P, Di Loreto C, Doni A, Introna
M, Gabrielli A.; Expression and production of the long pentraxin PTX3 in rheumatoid arthritis (RA).
Clin Exp Immunol. 2000 Jan;119(1):196-202.
6) Polentarutti N, Bottazzi B, Di Santo E, Blasi E, Agnello D, Ghezzi P, Introna M, Bartfai T, Richards G, Mantovani A.; Inducible
expression of the long pentraxin PTX3 in the central nervous system. J Neuroimmunol. 2000 Jul 1;106(1-2):87-94.
7) Peri G, Introna M, Corradi D, Iacuitti G, Signorini S, Avanzini F, Pizzetti F, Maggioni AP, Moccetti T, Metra M, Cas LD, Ghezzi P, Sipe
JD, Re G, Olivetti G, Mantovani A, Latini R.; PTX3, A prototypical long pentraxin, is an early indicator of acute myocardial infarction in
humans.; Circulation. 2000 Aug 8;102(6):636-41.
8) Vidal Alles V, Bottazzi B, Peri G, et al. Inducible expression of PTX3, a new member of the pentraxin family, in human mononuclear
phagocytes. Blood. 1994;84:3483–3493.
9) Michael S. Rolph, Sabine Zimmer, Barbara Bottazzi, Cecilia Garlanda, Alberto Mantovani, and Göran K. Hansson ; Production of the
Long Pentraxin PTX3 in Advanced Atherosclerotic Plaques ; Arterioscler Thromb Vasc Biol 2002 22: e10 - e14
10) Emanuela Napoleone, Angelomaria Di Santo, Antonio Bastone, Giuseppe Peri, Alberto Mantovani, Giovanni de Gaetano,
Maria Benedetta Donati, and Roberto Lorenzet Long Pentraxin PTX3 Upregulates Tissue Factor Expression in Human
Endothelial Cells: A Novel Link Between Vascular Inflammation and Clotting Activation
Arterioscler Thromb Vasc Biol 2002 22: 782 - 787
References