From the Department of Molecular Genetics, Weizmann
Institute of Science, Rehovot 76100, Israel and the ¶ Department
of Pathology, Sheba Medical Center, Ramat Gan 52621, Israel
Received for publication, September 12, 2000, and in revised form, December 13, 2000
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Adipose tissues consisting of adipocytes,
microvasculature, and stroma are completely ablated upon
over-expression of leptin in rats. This tissue regression is mediated
by enhanced lipid beta-oxidation, adipocyte dedifferentiation,
and apoptosis. To further characterize this phenomenon, we studied the
possible effect of leptin on the adipose microvasculature. Tissue
microvasculature is maintained by the interplay between positive and
negative signals mediated by factors including vascular endothelial
growth factor (VEGF), basic fibroblast growth factor,
angiopoietin-1 (Ang-1), and Ang-2. Expression of the negative signal
Ang-2 was reported in fetal tissues and in the adult ovary, which
undergoes vascular remodeling or regression. We demonstrate that leptin
induces the expression of Ang-2 in adipose tissue without a concomitant
increase in VEGF. Induction of Ang-2 occurred in an autocrine manner,
as demonstrated in cultured adipocytes but not in several other cell types. This tissue-specific induction of Ang-2 coincided with initiation of apoptosis in adipose endothelial cells. We propose that
induction of Ang-2 by leptin in adipose cells is one of the events
leading to adipose tissue regression.
Leptin, a product of the obese
(ob)1 gene, is a
cytokine secreted by adipocytes, which regulates adipose tissue mass by
restricting food intake and elevating the expenditure of metabolic
energy (1, 2). These activities of leptin are mediated through the
hypothalamic leptin receptor (OB-Rb) (3, 4). Over-expression of leptin
in adult rats leads to complete disappearance of adipose tissues, a
phenomenon not seen in pair-fed animals. Furthermore, unlike pair-fed
rats, no other tissue is affected, suggesting distinct leptin-induced
mechanisms of adipose tissue ablation (5-7). Several mechanisms of
adipose tissue regression were demonstrated, including lipid depletion
adipose cell apoptosis, and adipocyte dedifferentiation (8-12).
Changes in adipose or other tissue mass require a concerted adaptation
of blood supply, adjusted by the growth or regression of blood vessels
(13). The hypoxia-induced vascular endothelial growth factor (VEGF)
induces endothelial cell proliferation and angiogenesis (14). Two other
angiogenic factors, angiopoietin-1 and -2 (Ang-1 and Ang-2), which bind
to a common endothelial cell receptor (Tie2), have been identified (15,
16). Ang-1 is a receptor agonist (17), constitutively expressed in many
tissues, whereas Ang-2 is a receptor antagonist whose expression is
limited to sites of vascular remodeling. (16, 18-21).
Recently, leptin was reported to act as an angiogenic factor in several
model systems (22, 23). However, its possible angiogenic function has
not been studied in adipose tissue. In fact, the leptin-induced
ablation of adipose tissues (5) suggests a process involving
concomitant loss of adipose vasculature rather than enhanced
angiogenesis. In the present study, we show that leptin induces Ang-2
in adipose tissue without a concomitant increase in VEGF or Ang-1.
These findings suggest a specific and direct mechanism of
leptin-induced loss of the adipose vasculature.
Cell Cultures and Reagents--
Swiss 3T3-F442A murine
pre-adipocytes (24) were grown in DMEM with 10% calf serum. To induce
differentiation into mature adipocytes, confluent cell cultures were
maintained in DMEM supplemented with 10% fetal bovine serum for
6 days. Recombinant mouse leptin was purchased from R & D Systems
(Minneapolis). Polyclonal antibodies to human Ang-2 were obtained from
Santa Cruz Biotechnology (Santa Cruz, CA). An in situ cell
death detection kit, AP, was purchased from Roche Molecular Biochemicals.
Immunohistochemistry--
Subcutaneous fat was removed from
various strains of mice at the indicated times and fixed with 4%
paraformaldehyde, and paraffin sections were prepared. Apoptosis was
determined in situ by a TUNEL assay on the paraffin sections
using alkaline phosphatase and nuclei counted in five fields at ×200
(25).
RNA Blot Analysis--
Cells were maintained at low (0.5%)
serum for 16 h and then treated with murine leptin (1 µg/ml) for
different time periods. Total RNA was isolated either from adipose
tissue or from cultured cells with the TRI reagent kit
(Molecular Research Center Inc.). Aliquots (1.5 µg) were subjected to
RNA blot analysis as described (26). Probes for RNA blot analysis were
prepared by RT-PCR with total RNA and the following primers
(GenBankTM accession numbers are in parentheses):
muAng-2 mRNA (AF4326), nucleotides 637-657 and 1147-1167; muVEGF
(M95200), nucleotides 385-406 and 962-980; muActin mRNA (J00691),
nucleotides 1670-1691 and 2452-2431.
Quantitative RT-PCT--
Total RNA was isolated and reverse
transcribed in 20-µl volumes using RNase H Leptin Induces Angiopoietin-2 and Apoptosis in Adipose
Tissues--
To determine the effects of leptin on the expression of
angiogenic and angiostatic factors in adult adipose tissue, we injected murine leptin (0.1-5 µg/g, intraperitoneal) at times 0 and 9 h into 8-10-week-old obese (C57Bl-ob/ob) female mice, lacking
endogenous leptin production. A noticeable weight loss was observed
after 48 h in mice receiving
It was previously reported that intracerebroventricular injection of
leptin for 5 days induces significant apoptosis in rat adipose tissues
(11). We found by TUNEL staining an extensive increase in the number of
apoptotic nuclei as soon as 24 h after intraperitoneal
injection of leptin with further increases at 48 h (Fig.
2). Apoptotic nuclei were seen in
particularly in endothelial cells, identified by their elongated
shape and location around erythrocyte-containing microvessels (Fig.
3).
Leptin-deficient Mice Have a Reduced Adipose Ang-2--
We then
compared basal Ang-2 mRNA levels in wild-type mice,
ob/ob mice, and C57Bl-db/db mice lacking the
long-form leptin receptor (OB-Rb). Quantitative RT-PCR revealed that
Ang-2 mRNA was expressed in the adipose tissue of all three mouse
strains, indicating that leptin was not essential for Ang-2 expression (Fig. 4). However, basal Ang-2 mRNA
was significantly lower in adipose tissues of ob/ob mice,
suggesting that endogenous leptin plays an important role in inducing
Ang-2 mRNA expression in adipose tissues. C57Bl-db/db
mice have a constitutively elevated level of endogenous leptin, and yet
their adipose Ang-2 was significantly lower compared with that of
wild-type mice. This result indicates that leptin induces Ang-2 by
acting through OB-Rb (Fig. 4). Although OB-Rb is expressed abundantly
in the hypothalamus, it is also expressed in some other cell types
including adipocytes (4). Therefore, induction of Ang-2 by leptin may
be regulated either centrally or locally.
Leptin-induces Ang-2 and No VEGF in Cultured Adipocytes--
To
test whether leptin can induce Ang-2 expression by acting directly on
adipocytes, in vitro experiments were performed using 3T3-F442A cells. Upon transfer to medium containing fetal bovine serum,
these cells differentiate into adipocytes (24, 27, 28). Leptin
(1 µg/ml) induced Ang-2 mRNA expression in differentiated 3T3-F442A adipocytes but not in pre-adipocytes, as determined by RNA
blot analysis (Fig. 5). This observation
indicated that Ang-2 was induced by leptin in the adipose tissue in an
autocrine manner. Several other cell lines were tested for Ang-2
induction by leptin. Although many of them expressed a low basal level
of Ang-2, induction by leptin occurred only in adipocytes (data not shown).
We then studied the effect of leptin on VEGF mRNA induction in
cultured adipocytes. Basal levels of VEGF mRNA were detected in
cultured pre-adipocytes, but expression was reduced following their
differentiation into adipocytes. No induction of VEGF was observed in
leptin-treated adipocytes in culture. In contrast, leptin induced VEGF
mRNA expression in pre-adipocytes (Fig. 5).
The kinetics and the precise levels of Ang-2 and VEGF mRNA
induction in cultured adipocytes and pre-adipocytes were further measured by quantitative RT-PCR. Significant induction of Ang-2 mRNA was observed in adipocytes at 10 h, and expression was
even higher at 24 h (Fig. 6). In
contrast, no induction of VEGF mRNA was seen in leptin-treated
adipocytes. The induction pattern was reversed in pre-adipocytes.
Leptin-induced VEGF mRNA expression was significantly increased at
48 h, whereas no induction of Ang-2 was observed. The somewhat
delayed kinetics of VEGF mRNA induction suggests an indirect effect
of leptin on VEGF gene expression (Fig.
7).
Serving as an energy depot, the adipose tissue is endowed with the
unique ability to expand and contract throughout adult life. This role
requires the concomitant adaptation of the adipose microvasculature. In
this study, we investigated the possible role of leptin on adipose
microvasculature. Adipose tissues consist of several cell types,
including adipocytes and fibroblasts. Our studies with these isolated
cell types showed that leptin is capable of inducing both Ang-2 and
VEGF in vitro in a cell-specific manner (Figs. 5-7).
Indeed, induction of VEGF by leptin may account for its reported
angiogenic activity in several model systems (22, 23). However, in
adipose tissues of ob/ob mice, leptin profoundly induced
Ang-2 without a concomitant induction of VEGF, thereby providing a
strong angiostatic rather than angiogenic signal in vivo
(Fig. 1). Such a process may contribute to the ablation of all adipose
tissues reported upon over-expression of leptin in rats (5).
Ablation of adipose tissue is mediated at least in part by
leptin-induced apoptosis, as reported by Qian et al. (11).
Our data support this mechanism and further show that DNA nicking occurred mainly in the nuclei of endothelial cells (Fig. 3). Induction of Ang-2 by leptin in adipocytes and lack of VEGF may have triggered apoptosis in the endothelial cells. A similar role has been assigned to
Ang-2 in the regression of ovarian follicles as well as tumor blood
vessels (14, 20, 29).
The strong induction of Ang-2 by leptin in adipose tissues and in
cultured adipocytes adds these cells to the rather limited number of
normal adult cell types that express Ang-2. Leptin appears to be a
very potent inducer of Ang-2 as compared with the previously reported
agents, VEGF, bFGF, hypoxia, and tumor necrosis factor- Although this is the first report of Ang-2 expression in adipocytes,
high level expression of VEGF was found in omental adipocytes (33),
providing a rationale for its well established use in surgery to
accelerate wound healing (34). We measured rather low basal VEGF
mRNA levels in subcutaneous adipose tissues, suggesting that
adipose tissues may differ in their VEGF content. It is also possible,
however, that reduced oxygenation induces the grafted omental fat to
secrete elevated levels of VEGF.
In addition to its central effects, several peripheral effects of
leptin were reported, but their mechanisms have not all been elucidated
(10, 22, 23, 35, 36). Induction of Ang-2 by leptin in cultured
adipocytes provides convincing evidence that leptin also acts directly
on peripheral targets. Such autocrine induction provides a novel
regulatory pathway, linking leptin to vascular homeostasis in adipose tissue.
INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES
EXPERIMENTAL PROCEDURES
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES
reverse
transcriptase (SuperScript II, Life Technologies, Inc.) with 1 µg
(N)6 random primer (New England Biolabs). Aliquots (2 µl)
of the reverse transcription products were used for quantitative PCR in
the LightCyclerTM PCR and Detection System using the
FastStart DNA Master SYBER Green I kit (both from Roche Molecular
Biochemicals) as described by the manufacturer. The following sense and
antisense primers were used (GenBankTM accession
numbers are in parentheses): muAng-2 (AF4326), nucleotides 484-502 and
1640-1620; huVEGF (M32977), nucleotides 358-379 and 962-980; mouse
actin (M12866), nucleotides 244-263 and 973-954.
RESULTS
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES
2 × 1 µg/g leptin (average
weight 62.7 ± 1.0 g versus 65.4 ± 0.5 g, n = 6). Total RNA was isolated from subcutaneous
adipose tissues at 0, 24, and 48 h after the first leptin dose,
and the levels of Ang-1, Ang-2, and VEGF mRNA were evaluated by RNA
blotting. Ang-1 mRNA was below the limit of detection of this
analysis both before and after leptin treatment (data not shown). A
significant induction of Ang-2 was observed in the leptin-treated (5 µg/g) animals. In contrast, the level of VEGF mRNA was not
increased after 24 h and was only slightly elevated at 48 h
(Fig. 1A). Tissue Ang-2 was
analyzed by immunoblotting at 48 h post-leptin injection. No Ang-2
was detected by this method at time 0 or in tissues of mice injected
with low dose (0.1 µg/g) leptin, whereas Ang-2 was induced in mice
treated with 2-5 µg/g of leptin (Fig. 1B). These results
demonstrated that leptin treatment induced Ang-2 in adipose tissues of
C57Bl-ob/ob mice in vivo. The lack of parallel
induction of VEGF by leptin indicated that the overall effect of leptin
treatment on the adipose vasculature was angiostatic and not
angiogenic.
View larger version (36K):
[in a new window]
Fig. 1.
Leptin induces angiopoietin-2 in adipose
tissues of C57Bl ob/ob mice. A, time
course of Ang-2 induction by leptin in adipose tissue of
ob/ob mice. C57Bl-ob/ob mice were injected with
leptin (2 × 5 µg/g), and total RNA was extracted from adipose
tissue at the indicated times and subjected to RNA blot analysis with
probes corresponding to murine Ang-2, VEGF, and actin mRNA. Ang-2
was induced 2.9 ± 0.4-fold, p < 0.05, n = 3 at 24 h and 16.0 ± 0.31-fold,
p < 0.01, n = 3, at 48 h; VEGF
was not significantly induced (1.4 ± 0.1-fold, n = 3, p > 0.1 at 48 h). B, dose
response of Ang-2 induction in adipose tissue of ob/ob mice.
C57Bl-ob/ob mice were injected with leptin, and proteins
were extracted from adipose tissue after 48 h. Ang-2 was
determined by immunoblot analysis. The nonspecific band
(N.S) was used for normalization of protein loading on the
immunoblot. Lane 1, control ob/ob mouse;
lanes 2-4, leptin-injected mice (2 × 0.1, 2 × 1, and 2 × 5 µg/g, respectively).
View larger version (50K):
[in a new window]
Fig. 2.
Leptin induces apoptosis in adipose
tissues of C57Bl-ob/ob mice. Mice were injected
with murine leptin (2 × 1 µg/g weight), and adipose tissues
were removed after 24 or 48 h and fixed with formaldehyde.
Apoptotic nuclei were visualized by TUNEL staining (red) and
counter-stained with hematoxylin. A-C, control mice
(A) and leptin-treated mice at 24 (B) and 48 h (C). D, apoptotic index at 24 and 48 h.
View larger version (180K):
[in a new window]
Fig. 3.
Leptin induces apoptosis of
endothelial cells. Higher magnification of adipose tissue from
leptin-treated mice at 48 h (see Fig. 2 for details) revealed
apoptotic nuclei of endothelial cells around blood microvessels
(indicated by open arrowheads).
View larger version (70K):
[in a new window]
Fig. 4.
Comparison of basal Ang-2 in adipose tissues
of various mouse strains. Total RNA was extracted from the
subcutaneous adipose tissue of C57Bl, C57Bl-ob/ob, and
C57Bl-db/db mice. RNA was subjected to quantitative RT-PCR
(n = 6). Ang-2 mRNA levels in the ob/ob
and db/db mutants were significantly lower than in the
parental strain. Inset, agarose gel electrophoresis of
the PCR products at cycle 30.
View larger version (57K):
[in a new window]
Fig. 5.
Leptin induces VEGF in fibroblasts and Ang-2
in cultured adipocytes. Cultures of undifferentiated mouse
3T3-F442A pre-adipocytes (lanes 1 and 2) and
differentiated adipocytes (lanes 3 and 4) were
treated with leptin (1 µ g/ml, lanes 2 and 4)
or untreated (lanes 1 and 3). Total RNA was
extracted at 24 (Ang-2) and 48 h (VEGF) and
subjected to RNA blotting with probes to mouse Ang-2, VEGF, and actin.
Note the selective induction of Ang-2 mRNA and the reduction in the
VEGF mRNA in differentiated cells.
View larger version (43K):
[in a new window]
Fig. 6.
Quantitative RT-PCR of leptin-induced Ang-2
in cultured adipocytes. Cultures of differentiated mouse 3T3-F442A
adipocytes were induced with leptin (1 µg/ml). Total RNA was
extracted at different time points and subjected to quantitative RT-PCR
with probes to mouse Ang-2 and actin (n = 6).
Significant induction of Ang-2 mRNA (5.2 ± 0.8-fold,
p > 0.02, n = 5) was observed in
adipocytes at 10 h and was even higher (43 ± 4.4-fold,
n = 2) at 24 h. Inset, agarose gel
electrophoresis of the PCR products at cycle 30.
View larger version (42K):
[in a new window]
Fig. 7.
Quantitative RT-PCR of leptin-induced VEGF in
cultured pre-adipocytes. Cultures of undifferentiated mouse
3T3-F442A cells were induced with leptin (1 µg/ml). Total RNA was
extracted at different time points and subjected to quantitative RT-PCR
with probes to mouse VEGF and actin. Significant induction was noticed
only at 48 h (n = 6). Inset, agarose
gel electrophoresis of the PCR products at cycles 23 and 30.
DISCUSSION
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES
(19,
30, 31). Recently, the induction of genes following leptin
administration to ob/ob mice was studied using
oligonucleotide microarrays. Surprisingly, Ang-2 induction was not
observed by this method (32). Our results, obtained both in
vivo and in vitro, were reproduced by three independent
methods. It is therefore possible that induction of certain genes may
escape detection by the current DNA array techniques.
![]() |
ACKNOWLEDGEMENTS |
---|
We thank S. Barak for excellent technical help.
![]() |
FOOTNOTES |
---|
* This work was supported by the Ares Serono Group of Companies.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
§ These authors contributed equally to the study.
Incumbent of the Edna and Maurice Weiss Chair of cytokine
research. To whom correspondence should be addressed. E-mail:
menachem.rubinstein@weizmann.ac.il.
Published, JBC Papers in Press, January 4, 2001, DOI 10.1074/jbc.C000634200
![]() |
ABBREVIATIONS |
---|
The abbreviations used are: ob, obese gene; OB-Rb, leptin receptor; VEGF, vascular endothelial growth factor; Ang, angiopoietin; RT-PCR, reverse transcription-polymerase chain reaction; DMEM, Dulbecco's modified Eagle's medium; TUNEL, terminal deoxynucleotidyltransferase nick end labeling.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1. | Zhang, Y., Proenca, R., Maffei, M., Barone, M., Leopold, L., and Friedman, J. M. (1994) Nature 372, 425-432[CrossRef][Medline] [Order article via Infotrieve] |
2. | Considine, R. V., and Caro, J. F. (1997) Int. J. Biochem. Cell Biol. 29, 1255-1272[CrossRef][Medline] [Order article via Infotrieve] |
3. | Tartaglia, L. A., Dembski, M., Weng, X., Deng, N. H., Culpepper, J., Devos, R., Richards, G. J., Campfield, L. A., Clark, F. T., Deeds, J., Muir, C., Sanker, S., Moriarty, A., Moore, K. J., Smutko, J. S., Mays, G. G., Woolf, E. A., Monroe, C. A., and Tepper, R. I. (1995) Cell 83, 1263-1271[Medline] [Order article via Infotrieve] |
4. | Lee, G. H., Proenca, R., Montez, J. M., Carroll, K. M., Darvishzadeh, J. G., Lee, J. I., and Friedman, J. M. (1996) Nature 379, 632-635[CrossRef][Medline] [Order article via Infotrieve] |
5. |
Chen, G.,
Koyama, K.,
Yuan, X.,
Lee, Y.,
Zhou, Y. T.,
O'Doherty, R.,
Newgard, C. B.,
and Unger, R. H.
(1996)
Proc. Natl. Acad. Sci. U. S. A.
93,
14795-14799 |
6. |
Flier, J. S.
(1997)
Proc. Natl. Acad. Sci. U. S. A.
94,
4242-4245 |
7. |
Wang, Z. W.,
Zhou, Y. T.,
Kakuma, T.,
Lee, Y.,
Higa, M.,
Kalra, S. P.,
Dube, M. G.,
Kalra, P. S.,
and Unger, R. H.
(1999)
Proc. Natl. Acad. Sci. U. S. A.
96,
10373-10378 |
8. | Fruhbeck, G., Aguado, M., and Martinez, J. A. (1997) Biochem. Biophys. Res. Commun. 240, 590-594[CrossRef][Medline] [Order article via Infotrieve] |
9. |
Zhou, Y. T.,
Shimabukuro, M.,
Koyama, K.,
Lee, Y.,
Wang, M. Y.,
Trieu, F.,
Newgard, C. B.,
and Unger, R. H.
(1997)
Proc. Natl. Acad. Sci. U. S. A.
94,
6386-6390 |
10. |
Wang, M. Y.,
Lee, Y.,
and Unger, R. H.
(1999)
J. Biol. Chem.
274,
17541-17544 |
11. |
Qian, H.,
Azain, M. J.,
Compton, M. M.,
Hartzell, D. L.,
Hausman, G. J.,
and Baile, C. A.
(1998)
Endocrinology
139,
791-794 |
12. |
Zhou, Y. T.,
Wang, Z. W.,
Higa, M.,
Newgard, C. B.,
and Unger, R. H.
(1999)
Proc. Natl. Acad. Sci. U. S. A.
96,
2391-2395 |
13. | Crandall, D. L., Hausman, G. J., and Kral, J. G. (1997) Microcirculation 4, 211-232[Medline] [Order article via Infotrieve] |
14. |
Hanahan, D.
(1997)
Science
277,
48-50 |
15. | Davis, S., Aldrich, T. H., Jones, P. F., Acheson, A., Compton, D. L., Jain, V., Ryan, T. E., Bruno, J., Radziejewski, C., Maisonpierre, P. C., and Yancopoulos, G. D. (1996) Cell 87, 1161-1169[Medline] [Order article via Infotrieve] |
16. |
Maisonpierre, P. C.,
Suri, C.,
Jones, P. F.,
Bartunkova, S.,
Wiegand, S. J.,
Radziejewski, C.,
Compton, D.,
McClain, J.,
Aldrich, T. H.,
Papadopoulos, N.,
Daly, T. J.,
Davis, S.,
Sato, T. N.,
and Yancopoulos, G. D.
(1997)
Science
277,
55-60 |
17. |
Suri, C.,
McClain, J.,
Thurston, G.,
McDonald, D. M.,
Zhou, H.,
Oldmixon, E. H.,
Sato, T. N.,
and Yancopoulos, G. D.
(1998)
Science
282,
468-471 |
18. |
Witzenbichler, B.,
Maisonpierre, P. C.,
Jones, P.,
Yancopoulos, G. D.,
and Isner, J. M.
(1998)
J. Biol. Chem.
273,
18514-18521 |
19. |
Mandriota, S. J.,
and Pepper, M. S.
(1998)
Circ. Res.
83,
852-859 |
20. | Goede, V., Schmidt, T., Kimmina, S., Kozian, D., and Augustin, H. G. (1998) Lab. Investig. 78, 1385-1394[Medline] [Order article via Infotrieve] |
21. |
Otani, A.,
Takagi, H.,
Oh, H.,
Koyama, S.,
Matsumura, M.,
and Honda, Y.
(1999)
Invest. Ophthalmol. Vis. Sci.
40,
1912-1920 |
22. |
Sierra-Honigmann, M. R.,
Nath, A. K.,
Murakami, C.,
Garcia-Cardena, G.,
Papapetropoulos, A.,
Sessa, W. C.,
Madge, L. A.,
Schechner, J. S.,
Schwabb, M. B.,
Polverini, P. J.,
and Flores-Riveros, J. R.
(1998)
Science
281,
1683-1686 |
23. |
Bouloumie, A.,
Drexler, H. C.,
Lafontan, M.,
and Busse, R.
(1998)
Circ. Res.
83,
1059-1066 |
24. | Green, H., and Kehinde, O. (1975) Cell 5, 19-27[Medline] [Order article via Infotrieve] |
25. | Gavrieli, Y., Sherman, Y., and Ben-Sasson, S. A. (1992) J. Cell Biol. 119, 493-501[Abstract] |
26. | Novick, D., Kim, S. H., Fantuzzi, G., Reznikov, L. L., Dinarello, C. A., and Rubinstein, M. (1999) Immunity 10, 127-136[Medline] [Order article via Infotrieve] |
27. | Green, H., and Kehinde, O. (1979) J. Cell. Physiol. 101, 169-171[Medline] [Order article via Infotrieve] |
28. |
Mandrup, S.,
Loftus, T. M.,
MacDougald, O. A.,
Kuhajda, F. P.,
and Lane, M. D.
(1997)
Proc. Natl. Acad. Sci. U. S. A.
94,
4300-4305 |
29. |
Holash, J.,
Maisonpierre, P. C.,
Compton, D.,
Boland, P.,
Alexander, C. R.,
Zagzag, D.,
Yancopoulos, G. D.,
and Wiegand, S. J.
(1999)
Science
284,
1994-1998 |
30. |
Oh, H.,
Takagi, H.,
Suzuma, K.,
Otani, A.,
Matsumura, M.,
and Honda, Y.
(1999)
J. Biol. Chem.
274,
15732-15739 |
31. | Kim, I., Kim, J. H., Ryu, Y. S., Liu, M., and Koh, G. Y. (2000) Biochem. Biophys. Res. Commun. 269, 361-365[CrossRef][Medline] [Order article via Infotrieve] |
32. |
Soukas, A.,
Cohen, P.,
Socci, N. D.,
and Friedman, J. M.
(2000)
Genes Dev.
14,
963-980 |
33. | Zhang, Q. X., Magovern, C. J., Mack, C. A., Budenbender, K. T., Ko, W., and Rosengart, T. K. (1997) J. Surg. Res. 67, 147-154[CrossRef][Medline] [Order article via Infotrieve] |
34. | Silverman, K. J., Lund, D. P., Zetter, B. R., Lainey, L. L., Shahood, J. A., Freiman, D. G., Folkman, J., and Barger, A. C. (1988) Biochem. Biophys. Res. Commun. 153, 347-352[Medline] [Order article via Infotrieve] |
35. |
Cohen, B.,
Novick, D.,
and Rubinstein, M.
(1996)
Science
274,
1185-1188 |
36. |
Barkan, D.,
Jia, H.,
Dantes, A.,
Vardimon, L.,
Amsterdam, A.,
and Rubinstein, M.
(1999)
Endocrinology
140,
1731-1738 |