First published online 3 March 2004
doi: 10.1242/dev.01056
Development 131, 1577-1586 (2004)
Published by The Company of Biologists 2004
PTX3 plays a key role in the organization of the cumulus oophorus extracellular matrix and in in vivo fertilization
Antonietta Salustri1,*,
Cecilia Garlanda2,*,
Emilio Hirsch3,*,
Marika De Acetis3,
Alessia Maccagno1,
Barbara Bottazzi2,
Andrea Doni2,
Antonio Bastone2,
Giovanna Mantovani4,
Paolo Beck Peccoz4,
Giovanni Salvatori5,
David J. Mahoney6,
Anthony J. Day6,
Gregorio Siracusa1,
Luigina Romani7 and
Alberto Mantovani2,8,
1 Department of Public Health and Cell Biology, University of Rome Tor Vergata,
Rome 00133, Italy
2 Department of Immunology and Cell Biology, Mario Negri Institute for
Pharmacological Research, Milan 20157, Italy
3 Department of Genetics, Biology and Biochemistry, University of Turin, Turin
10126, Italy
4 Institute of Endocrinology, Università degli Studi di Milano, Milan
20100, Italy
5 SigmaTau SpA, Pomezia, Rome 00040, Italy
6 MRC Immunochemistry Unit, Department of Biochemistry, University of Oxford,
Oxford OX1 3QU, UK
7 Microbiology Section, Department of Experimental Medicine and Biochemical
Sciences, University of Perugia, Perugia 05122, Italy
8 Centro IDET, Institute of General Pathology, Università degli Studi di
Milano, Milan 20100, Italy

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Fig. 1. Defective cumulus expansion in Ptx3/
mice. (A-D) Morphology of cumuli oophori during matrix deposition. Micrographs
show individual preovulatory follicles 10 hours after hCG (A,B) and an
enlargement of the enclosed cumuli (C,D). (E-H) Morphology of
Ptx3+/ and Ptx3/
ovulated cumuli immediately after isolation (E,F), or after 1 hour of in vitro
culture (G,H). Scale Bars: 100 µm in A,B,E-H; 50 µm in C,D.
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Fig. 2. PTX3 is expressed by cumulus cells in the preovulatory follicle and
localizes in the matrix. (A) In situ hybridization of an ovary isolated from a
naturally cycling mouse. (B) Kinetics of Ptx3 mRNA expression in
ovaries during hormonally induced ovulation. Each lane was loaded with 10
µg of total RNA. Ethidium bromide staining of the gel is shown in the lower
panel. (C) Detection of PTX3 protein in ovulated intact cumuli oophori (COC),
isolated cumulus cells (CC), denuded oocytes (O) and cumulus matrix (matrix)
assessed by western blotting. (D) Immunofluorescence analysis (left panel) and
phase contrast (right panel) of a cumulus oophorus. Scale bars: 100 µm in
A; 50 µm in D.
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Fig. 3. PTX3 synthesis by in vitro cultured cumulus cells. (A) COCs (30/20 µl)
were cultured for 16 hours in the absence (BM, basal medium) or presence of
the indicated stimuli. (B) Cumulus cells isolated from 30 COCs were cultured
for 16 hours in the presence of 60 oocytes or FSH, or both. PTX3 was assessed
in the matrix and medium by western blotting.
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Fig. 4. Effects of PTX3 on matrix organization and cumulus expansion. (A) PTX3 is
necessary for matrix assembly and cumulus expansion. COCs (20/20 µl) were
cultured for 16 hours in the presence of FSH and FBS, and with 1 µg/ml
recombinant PTX3 where indicated. HA evaluation was performed as indicated in
Materials and methods. Cumulus expansion and HA distribution between matrix
and medium were assessed for (a) Ptx3+/ cumuli, (b)
Ptx3/ cumuli and (c)
Ptx3/ cumuli cultured with recombinant PTX3.
Reported data refer to one representative experiment of three performed. Scale
bar: 100 µm. (B) Degradation of expanded cumulus matrix is not affected by
recombinant PTX3. Degradation of the HA-rich matrix was assessed at 24 and 28
hours of culture by calculating the proportion of the total HA released in the
culture medium, as described previously
(D'Alessandris et al., 2001 ).
In the upper panel the total amount of HA (pmol hexosamine)/COC at each time
culture is reported. Error lines indicate the standard deviation of duplicate
cultures.
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Fig. 6. Co-localization of PTX3 and HA in ovulated cumuli.
Ptx3+/ cumuli were stained for HA (red), PTX3
(green) and chromatin (blue), as reported in Materials and methods, and the
innermost (A-D) and outermost (E-H) layers of a cumulus were photographed
using a fluorescence microscope. HA histochemical staining (A,E); PTX3
immunostaining (B,F); merging of the two signals (C,G); and staining of
cumulus cell nuclei (D,H). Cumuli incubated with secondary probes only showed
no specific staining (data not shown).
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Fig. 7. Binding of PTX3 to TNFAIP6. (A) Binding of bHA (12.5 ng/well) or bPTX3
(22.2 pmol/well), or PBS as a control, to immobilized TNFAIP6 (25 pmol/well;
n=3). (B) Dose-dependent binding of different amounts of soluble
bPTX3 to immobilized Link_TNFAIP6 (25 pmol/well; n=4). (C) Effect of
different amounts of competitors (PTX3, HA, Link_TNFAIP6) on the interaction
of bPTX3 (200 ng/well) with Link_TNFAIP6-coated plates (n=4).
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Fig. 8. Binding of soluble PTX3 (2.2x106 M) to spermatozoa
as assessed by FACS (A) and imunofluorescence (B). (C) Differential
localization and binding of spermatozoa cultured on PTX3- or BSA-coated
plastic (P=0.013; Student's t-test).
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Fig. 9. Expression of PTX3 in human ovarian tissues. (A) PTX3 mRNA
expression by human cumulus cells in four different patients undergoing IVF.
Each lane was loaded with 10 µg of total RNA. Ethidium bromide staining of
the gel is shown in the lower panel. (B) Detection of PTX3 in human cumulus
matrix by western blot analysis. Lane 1, human cumuli; lane 2, recombinant
PTX3. (C) PTX3 protein levels in the follicular fluid of five different
patients undergoing IVF. The dotted line indicates PTX3 plasma levels in
healthy donors.
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Fig. 10. Schematic model of complex formed between PTX3 and TNFAIP6 in the cumulus
matrix that could act as a node to cross-link multiple HA chains.
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© The Company of Biologists Ltd 2004