Blood online
Home About Blood Authors Subscriptions Permission Advertising Public Access contact us
 

 
Advanced
Current Issue
First Edition
Future Articles
Archives
Submit to Blood
Search
American Society of Hematology
Meeting Abstracts
Email Alerts
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Right arrow Rights and Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Youssefian, T.
Right arrow Articles by Cramer, E. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Youssefian, T.
Right arrow Articles by Cramer, E. M.
Related Collections
Right arrow Hemostasis, Thrombosis, and Vascular Biology
Social Bookmarking
 Add to CiteULike   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

arrow to previous article Previous Article  |  Table of Contents  |  Next Article next article arrow

Blood, Vol. 89 No. 11 (June 1), 1997: pp. 4047-4057

Platelet and Megakaryocyte Dense Granules Contain Glycoproteins Ib and IIb-IIIa

By Tayebeh Youssefian, Jean-Marc Massé, Francine Rendu, Josette Guichard, and Elisabeth M. Cramer

From INSERM U.91, Hôpital Henri Mondor, Créteil, France.


    ABSTRACT
Abstract
Introduction
Methods
Results
Discussion
References

Platelets contain two main types of secretory organelles, the dense granules and the alpha -granules. P-selectin, a specific receptor for leukocytes that is present in the alpha -granule membrane, has also been demonstrated to be associated with the dense granule limiting membrane, showing that a relationship exists between these two types of secretory granules. We have previously shown that the plasma membrane receptors glycoproteins (Gp) IIb-IIIa and Ib are also present in the alpha -granule membrane. To document further the composition of the dense granule membrane, we have used immunoelectron microscopy in the present work to determine if the dense granule membrane also contains these glycoproteins. First, the cytochemical method of Richards and Da Prada (J Histochem Cytochem 25:1322, 1977), which specifically enhances dense body electron density, was combined with immunogold-labeled anti-Gp IIb-IIIa or anti-Gp Ib antibody. A consistent and reproducible labeling for Gp IIb-IIIa, but less for Gp Ib, was found in the membrane of platelet dense granules. Subsequently, double immunogold labeling was performed on frozen thin sections of resting platelets using antibodies directed against the dense body components granulophysin or P-selectin, followed by anti-Gp IIb-IIIa or anti-Gp Ib. Consistent labeling for Gp IIb-IIIa and weaker labeling for Gp Ib were detected in dense bodies. The possibility that the granulophysin-positive structures could be lysosomes was excluded by the presence of P-selectin. Immunogold labeling of isolated dense granule fractions confirmed these results. Identical findings were made on human cultured megakaryocytes using double immunolabeling. In conclusion, this study demonstrates the presence of Gp IIb-IIIa and Gp Ib on the dense granule membrane. This observation provides additionnal evidence of similarities between the alpha -granule and dense granule membranes and raises the possibility of a dual mechanism responsible for the formation of dense granules similar to that of alpha -granules, ie, endogenous synthesis as well as endocytosis from the plasma membrane.

    INTRODUCTION
Abstract
Introduction
Methods
Results
Discussion
References

BLOOD PLATELETS contain a variety of storage organelles that contribute to their hemostatic function by releasing their contents to the extracellular surroundings. There are two main types of secretory granules: the alpha -granules, which are the most prominent population in size and number, and the dense granules. The dense granules contain the vasoconstrictive agent 5-hydroxytryptamine (5-HT), the nonmetabolic pool of adenosine triphosphate and adenosine diphosphate, Ca2+ and Mg2+ have a fundamental role in hemostasis. Dense granules and alpha -granules are morphologically distinct,1 but recent studies showing the presence of P-selectin, a component of the alpha -granule membrane, in the dense granule membrane2 suggest a relationship between these organelles. It has been shown that alpha -granule biogenesis is a complex phenomenon involving both endogenous synthesis and endocytosis. The soluble proteins stored in the alpha -granule matrix are derived via exclusive synthesis in the megakaryocytes (MK), such as von Willebrand factor and thrombospondin,3,4 or through endocytosis of plasma proteins such as fibrinogen and albumin.3,5,6 Moreover, the proteins of the alpha -granule membrane can also be categorized in two groups. Some receptors are restricted to the alpha -granule limiting membrane and are absent from the plasma membrane such as P-selectin.7 Alternatively, several components of the platelet plasma membrane are also present in the alpha -granule membrane, including glycoprotein (Gp) IIb-IIIa8 and the Gp Ib-IX-V complex.9 In the present study, we have used cytochemistry and immunoelectron microscopy to investigate the different components of the dense granule membrane, focusing on two plasma membrane markers, Gp IIb-IIIa and Gp Ib.

    MATERIALS AND METHODS
Abstract
Introduction
Methods
Results
Discussion
References

Cells

Blood samples were drawn from normal healthy volunteers by venipuncture into plastic tubes containing ACD-C buffer (13 mmol/L citric acid, 6.8 mmol/L sodium citrate, 11.2 mmol/L glucose, pH 4.2). The platelet-rich plasma was obtained by centrifugation of the anticoagulated blood for 10 minutes at 100g at 22°C. The isolated platelets were obtained by centrifugation of the platelet-rich plasma for 10 minutes at 1,100g at 22°C and washed three times with Tyrode's buffer (360 mmol/L citric acid, 5 mmol/L KCl, 2 mmol/L CaCl2 , 1 mmol/L MgCl2 , 103 mmol/L glucose, pH 7.4) containing 3.5 mg/mL bovine serum albumin (BSA; Sigma Chemical Co, St Louis, MO) and 100 nmol/L prostaglandin E1 (Sigma). When platelets were treated for the cytochemical method of Richards and Da Prada,10 blood samples were directly harvested into the adequate fixative.

MKs were grown in liquid culture from bone marrow precursors obtained from normal adult marrow donors as previously described.3,8

Antibodies

Three antihuman polyclonal rabbit antibodies (anti-Gp IIb-IIIa,8 antiglycocalicin, and anti-P-selectin9 ) were kindly provided by Dr Michael Berndt (Victoria, Australia) and were used at 10 µg/mL. Antihuman granulophysin, a monoclonal mouse antibody kindly provided by Dr J.M. Gerrard (Winnipeg, Manitoba, Canada) was also used at 10 µg/mL.11 Gold-conjugated (10 and 15 nm) protein A purchased from the Department of Cell Biology (University of Utrecht, Utrecht, The Netherlands) was used at an 1/80 and 1/35 dilution, respectively. Goat antimouse and goat antirabbit IgG fractions coupled to 10 or 15 nm gold particles were purchased from British Biocell International (Cardiff, UK).

Electron Microscopy

Normal platelets and MK were prepared for immunoelectron microscopy by fixation in 1% glutaraldehyde in 0.1 mol/L phosphate buffer, pH 7.4, for 1 hour at 22°C; washed three times with the same buffer; embedded in sucrose; and frozen in liquid N2 . Alternatively, the cytochemical reaction of Richards and Da Prada10 was performed after fixation of blood in 3% glutaraldehyde in 0.1 mol/L sodium cacodylate buffer (pH 7.2) for 90 minutes, and the isolated platelets were obtained as described above and washed three times with 0.9% NaCl for 15 minutes. The cytochemical reaction was performed in 4% aqueous uranyl acetate (pH 3.9) overnight (18 hours) and the platelets were then washed once more in 0.9% NaCl. Platelets were embedded in glycolmethacrylate (GMA) followed by the performance of the immunochemical reactions on thin sections collected on grids according to the method of Bendayan.12 Sections were labeled by first incubating with the polyclonal rabbit antibodies diluted in Tris-buffered saline (TBS) containing 1% BSA and 4% normal goat serum for 2 hours at 22°C, washed three times with TBS containing 0.1% BSA, and then incubated with goat antirabbit gold (10 nm) for 1 hour at room temperature. The sections were counterstained with uranyl acetate and lead citrate. To identify the nature of labeled granules, double immunolabeling was performed on frozen thin sections using different-sized gold protein A conjugates or alternatively goat antirabbit antibody (GAR) coupled to 10-nm gold particles and goat antimouse antibody (GAM) coupled to 10-nm gold particles. To avoid cross-reactions between antibodies of the same species, a short fixation with 1% glutaraldehyde and saturation with 0.1% BSA was performed before the second round of labeling, according to the method of Slot et al.13 Samples were examined with a Philips CM10 electron microscope (Philips, Eindhoven, The Netherlands).


View larger version (167K):
[in this window]
[in a new window]
 
Fig 1. (a) Platelets treated for the cytochemical detection of dense granules by the uranaffin technique of Richards and Da Prada10 and then immunolabeled for Gp Ib (polyclonal anti-Gp Ib/GAR 10 nm). The gold label lines the plasma membrane (pm) and is occasionally found on alpha -granules (A). Moreover, a granule with a dense content (D) is also labeled for Gp Ib. (Original magnification × 40,000.) (Inset) High magnification of a dense granule displaying immunolabeling for Gp Ib. (Original magnification × 59,000.) (b) Platelets pretreated by the uranaffin technique of Richards and Da Prada,10 embedded in GMA, and then immunolabeled for Gp IIb-IIIa (polyclonal anti-Gp IIb-IIIa/GAR 10 nm). Gold label is evident along the plasma membrane (pm) as well as along the alpha -granules (A). Note that the limiting membrane of the two dense granules (D) is also strongly labeled. (Original magnification × 32,000.) (Insets) High magnification of dense granules labeled for Gp IIb-IIIa. (Original magnification × 59,000 and × 92,000.)


View larger version (113K):
[in this window]
[in a new window]
 
Fig 2. (a and b) Frozen sections of resting platelets labeled with the dense granule markers granulophysin and P-selectin to identify the morphology of these organelles on cryosections. (a) Labeling of P-selectin (polyclonal anti-P-selectin/protein A 10 nm). P-selectin is present along the alpha -granules (A) and labels the dense granules (D) that have been partially extracted. The absence of P-selectin permits distinction of the vacuolar structures of the OCS from the dense bodies. (Original magnification × 48,000.) (b) Labeling of granulophysin (monoclonal anti-granulophysin/GAM 10 nm). The gold marker labels vacuolar structures, such as the dense granule limiting membrane (D). Using this technique, the dense granule core appears to have been partially lost, which gives the dense granule a vacuolar appearance. alpha -Granules (A) and plasma membrane (pm) are negative. (Original magnification × 48,000.)

Immunogold Analysis of Isolated Dense Granules

Dense granules were isolated as described by Rendu et al.14 Dense granules were pelleted at the bottom of the metrizamide gradient in an almost pure fraction. The enhancement of the intrinsic opacity of dense granules was obtained either according to the method of White1 and further embedded in Epon for morphologic examination or according to the method of Richards and Da Prada10 and embedded in GMA for immunolabeling.

Controls

To avoid the detection of IgG contained in the platelets, the following controls were performed: replacement of the primary antibody by a nonimmune serum or omission of the primary antibody from the reaction.

    RESULTS
Abstract
Introduction
Methods
Results
Discussion
References

Immunoelectron Microscopic Detection of Gp Ib and Gp IIb-IIIa in the Dense Granule Membrane

Immunolabeling of Platelets Using a Dense Body Cytochemical Reaction

When platelets were treated with the cytochemical method of Richards and Da Prada,10 dense granules were identified because of their density due to the cytochemical reaction of 5'- phosphonucleotides of dense granules and the uranyl ions. Incubation of thin sections in the various sequential immunolabeling media tended to fade the electron density of dense granules, presumably because of the water solubility of the reaction products. Immunolabeling for Gp Ib was evident along the plasma membrane. The membrane of some of the alpha -granules stained weakly for Gp Ib, as described previously.9 Some labeling for Gp Ib was also found occasionally in the dense granule limiting membrane (Fig 1a). Immunogold staining for Gp IIb-IIIa gave the following pattern: conspicuous labeling of the plasma membrane as well as the alpha -granule membrane. In addition, the dense granule membrane was also consistently labeled (Fig 1b). Thus, Gp Ib and Gp IIb-IIIa appear to be present in the dense granule membrane.


View larger version (147K):
[in this window]
[in a new window]
 
Fig 3. Detection of Gp Ib in dense granules by double immunolabeling on frozen thin sections of platelets. (a) P-selectin (polyclonal anti-P-selectin/protein A 10 nm; arrowheads)/Gp Ib (polyclonal anti-Gp Ib/protein A 15 nm; arrows). P-selectin is present in the alpha -granules (A) and dense granules (D). Gp Ib is evident along the plasma membrane (pm), occasional OCS, and alpha -granules. The dense granule membrane (D) that is marked with P-selectin also contains gold marker for Gp Ib. (Original magnification × 46,500; inset, × 101,000.) (b) Granulophysin (monoclonal anti-granulophysin/GAM 10 nm; arrowheads)/Gp Ib (polyclonal anti-Gp Ib/protein A 15 nm; arrows). Granulophysin labels the dense granule membrane (D) but not the alpha -granules (A). Gp Ib is found essentially along the plasma membrane (pm). The OCS and some alpha -granules (A) are occasionaly labeled. It also double-labels the dense granule membrane (D) identified by the presence of granulophysin. (Original magnification × 46,500; inset, × 84,000.)


View larger version (157K):
[in this window]
[in a new window]
 
Fig 4. Detection of Gp IIb-IIIa on dense granules by double immunolabeling performed on frozen thin sections of platelets. (a) P-selectin (polyclonal anti-P-selectin/protein A 10 nm; arrowheads)/Gp IIb-IIIa (polyclonal anti-Gp IIb-IIIa/protein A 15 nm; arrows). The presence of P-selectin identifies alpha -granules (A) and the dense granule membrane (D). Gp IIb-IIIa lines the plasma membrane (pm) and the alpha -granule membrane (A). Note that it is present in the dense granule membrane (D), where it colocalizes with P-selectin. (Original magnification × 36, 000; inset, × 84,000.) (b) Granulophysin (monoclonal anti-granulophysin/GAM 10 nm; arrowheads)/Gp IIb-IIIa (polyclonal anti-Gp IIb-IIIa/protein A 15 nm; arrows). The anti-granulophysin labels the dense granule membrane, thus allowing identification of these structures (D). Gp IIb-IIIa is also found at their level. Gp IIb-IIIa labels the alpha -granule membrane (A) and the plasma membrane (pm) as well. (Original magnification × 44,000; inset, × 84,000.)

Ultrastructural Identification of Dense Granules on Frozen Thin Sections

During this type of cell preparation, the dense content of the dense granules is extracted and dense granules appear as vacuolar organelles.2 To distinguish these organelles from other vacuolar structures such as the open canalicular system (OCS), immunolabeling was performed using antibodies against the known dense granule marker granulophysin and against P-selectin, because it had been shown that the dense granule membrane contains this receptor.2 Immunolabeling for P-selectin was observed in the alpha -granules and strongly labeled some vacuolar structures that are dense granules that have been partially extracted (Fig 2a). Moreover, the OCS cisternae that appear as vacuoles on thin sections did not display immunolabeling for P-selectin and could thus be distinguished from the dense granules. Immunolabeling for granulophysin was also present on the electron luscent granules and vacuole-like structures that had been positively labeled for P-selectin and mostly restricted to these structures (Fig 2b). Because of this labeling pattern, we could thus identify dense granules on frozen thin sections. Occasional small granules with a dense matrix were labeled and were identified as platelet primary lysosomes.


View larger version (150K):
[in this window]
[in a new window]
 
Fig 5. Human MK double-labeled for the alpha -granule and dense granule marker P-selectin, combined with Gp Ib or Gp Iib-IIIa. (Inset) Human cultured MK are large in size and have an indented nucleus, numerous secretory granules, and a prominent demarcation membrane system. (Original magnification × 16,000.) (a) P-selectin (polyclonal anti-P-selectin/protein A 10 nm; arrowheads)/Gp Ib (polyclonal anti-Gp Ib/protein A 15 nm; arrows). P-selectin lines the alpha -granules (A) and the dense granule membrane (D) and is absent from the plasma membrane (pm) and demarcation membranes (dm). In contrast, Gp Ib lines the plasma membrane and demarcation membranes (dm). Gp Ib is also found within the dense granule membrane (D) colocalized with P-selectin. Mitochondria (m), as control structures, do not label. (Original magnification × 72,000.) (b) P-selectin (polyclonal anti-P-selectin/protein A 10 nm; arrowheads)/Gp IIb-IIIa (polyclonal anti-Gp IIb-IIIa/protein A 15 nm; arrows). Gp IIb-IIIa is classically located on the plasma membrane (pm) and alpha -granules (A). It also colocalizes with P-selectin in the alpha -granules and, noteworthily, within the dense granules (D). (Original magnification × 33,500.)

Double Immunolabeling

To confirm that both Gp Ib and Gp IIb-IIIa were associated with the dense granule membrane, double immunolabeling experiments were performed using antibodies against the dense granule markers granulophysin and P-selectin on frozen thin sections of resting platelets and MKs.

Platelets. When platelets had undergone double immunolabeling for the granule protein, P-selectin, together with Gp Ib, P-selectin was located in the alpha -granule membrane and the dense granules as described above. The same organelles also displayed labeling for Gp Ib. Plasma membrane was regularly and conspicuously labeled with Gp Ib, whereas the OCS was only occasionaly labeled, confirming that Gp Ib is essentially a plasma membrane component on nonstimulated platelets (Fig 3a). A similar result was obtained using double immunolabeling for granulophysin and Gp Ib, ie, the presence of Gp Ib in dense bodies that were also lined by granulophysin, with the exception that granulophysin only labeled the dense granule limiting membrane and not the alpha -granules (Fig 3b).

Using a similar approach, labeling for Gp IIb-IIIa was present in the membrane of the same vacuolar structures in which P-selectin and granulophysin were detected, permitting identification of these structures as dense granules. Gp IIb-IIIa was also present on the alpha -granule and plasma membranes (Fig 4a and b).

The mitochondria were negative for the four markers.

MK. Double immunolabeling of the frozen thin sections of the mature MK with P-selectin and Gp Ib showed colocalization of the two glycoproteins in the dense granule membrane (Fig 5a). Similarly, Gp IIb-IIIa was colocalized with P-selectin in the dense granule membrane (Fig 5b). Gp Ib and Gp IIb-IIIa were also observed on the plasma membrane and the demarcation membrane system of the MK. Prominent labeling of Gp IIb-IIIa and occasional labeling of Gp Ib was also present on the alpha -granule membrane as previously described. alpha -Granules displayed P-selectin labeling but were easily distinguished from the dense granules because of their characteristic morphology, size, dense nucleoid, and general electron density. It is noteworthy that, in mature MK, dense granule morphology was more identifiable than in platelets, with better preservation of their dense contents for unclear reasons.

Controls

The various control experiments led to the disappearance of immunogold labeling (not shown).

Dense Granule Fraction Analysis

Ultrastructural Aspects of the Dense Granule Fraction

An isolated dense granule subcellular fraction appeared to be highly pure when examined by electron microscopy (Fig 6a). Indeed, the most abundant recognizable organelles were well-preserved, intact granules of high electron density that were identified as dense bodies. Only scant broken granules and membranes were present.


View larger version (136K):
[in this window]
[in a new window]
 
Fig 6. (a) Electron microscopic examination of the dense granule fraction whose electron density has been enhanced by White's cytochemical technique. This shows the high purity of the fraction that is almost exclusively composed of dense bodies. Only few membranes and platelet granules of other types can be identified. (Original magnification × 18,500.) (b, c, and d) Immunolabeling of the dense granule fraction pretreated by the uranaffin technique of Richards and Da Prada10 and embedded in GMA. (b) Labeling of P-selectin (polyclonal anti-P-selectin/GAR 10 nm). P-selectin is present in the membrane of alpha -granules (A) and in some of the dense granules (D) that are still identifiable, but only discrete labeling is obtained. This might be caused by the interaction of the chemical solutions with the antigenic sites, which could have decreased their reactivity. (Original magnification × 38,500.) (c) Immunolabeling for Gp IIb-IIIa (polyclonal anti-Gp IIb-IIIa/GAR 10 nm) is similar to immunolabeling for P-selectin and is present in the membrane of some dense granules (D) as well as alpha -granules (A). (Original magnification × 38,500; inset, × 100,500.) (d) Immunolabeling for Gp Ib (polyclonal anti-Gp Ib/GAR 10 nm) is occasionaly found in the membrane of dense granules (D). alpha -Granules (A) present in this field are not labeled. (Original magnification × 38,500; inset, × 74,500.)

Immunolabeling of the Dense Granule Fraction

Immunolabeling for P-selectin, as a marker of dense granules, was observed in the membrane of some dense granules but not in all of them (Fig 6b). This might be caused by the interaction of the different chemical treatments (pH 3.9, presence of uranyl acetate complexes in the dense granules and GMA embedding), which decreased reactivity of the antigenic sites. Immunolabeling for Gp IIb-IIIa resembled immunolabeling for P-selectin (Fig 6c). Fewer dense granules were labeled for GPIb, with the granules displaying less gold particles than for Gp IIb-IIIa and P-selectin; small amounts of Gp Ib was detected in the alpha -granules, as previously described.9

    DISCUSSION
Abstract
Introduction
Methods
Results
Discussion
References

Platelet dense granules have engendred considerable interest because, like nervous tissue, they actively take up 5-HT and histamine and release 5-HT after reserpine treatment of platelets. They also greatly contribute to the hemostatic function of platelets. In this study, we have used cytochemical and immunogold labeling techniques at the ultrastructural level to specifically detect the dense granules of platelets and MK. Using combined immunolabeling, we investigated whether certain receptors found in the platelet plasma membrane as well as in the alpha -granule membrane would also be found in the dense granule limiting membrane. Dense granules are bound by a typical unit membrane. The proteins anchored in their membrane include granulophysin,11,15 a protein originally described as present in platelet lysosomes,16 as well as P-selectin, a leukocyte receptor that was first described in the alpha -granule membrane and that can redistribute to the plasma membrane after secretion.2 The occurence of P-selectin both in the alpha -granule and dense granule membrane is an argument in favor of searching for other markers of similarity. Moreover, the existence of a congenital platelet disease, alpha -delta storage pool disease, involving the association of alpha -granule abnormalities with dense granule deficiencies, is additional evidence for a close relationship.17,18 Finally, disorders of secretion of one kind of granule is often linked to abnormal secretion of the other. This was described in the Grey platelet syndrome, a congenital alpha -granule deficiency19 in which dense granule release is impaired, and in storage pool disease, defined as a decrease in the number and content of dense granules that is also classically characterized by abnormal alpha -granule release.20

alpha -Granules are formed by a dual mechanism: endogenous MK synthesis of proteins such as von Willebrand factor and thrombospondin3,4 and a mechanism of endocytosis of circulating proteins, eg, fibrinogen and Igs.3,5,6 The composition of the alpha -granule limiting membrane also reflects these two pathways. Some components are specifically restricted to their membrane, such as P-selectin,7 osteonectin,21 and GMP 33,22 whereas other receptors are located both in the plasma membrane and within the alpha -granules. It has been hypothesized that they enter the alpha -granule membrane by means of endocytosis and recycling from the plasma membrane. This appears to be the case for Gp IIb-IIIa, the Gp Ib-IX-V complex, Gp IV, PECAM1, and CD9, which are all found in the alpha -granule membrane, but at different levels.8,9,23,24 To investigate the components and biogenesis of dense granules, we used the same technical approach as has been used for alpha -granule studies. We show that the two main platelet membrane receptors, Gp IIb-IIIa and Gp Ib, are also components of the dense granule limiting membrane. Indeed, when platelets were pretreated by the uranaffin reaction to enhance the electron density of dense granules, a consistent immunolabeling for Gp IIb-IIIa and weaker labeling for Gp Ib was observed in about 50% of identifiable dense bodies.

However, because the solubility of the cytochemical reaction product in the immunolabeling incubation medium sometimes rendered the identification of dense granules questionable, we confirmed these results by double immunolabeling performed on frozen sections. Because sucrose embedding does not preserve the electron density of the dense bodies (presumably because their content is lost during the procedure), we had to use specific markers to recognize their membrane from other vacuolar structures. This problem was formerly encountered by Israels et al,2 who described the ultrastuctural appearance of dense bodies as visualized on platelet cryosections and whose data are similar to our observations. To distinguish these empty granules from the vacuole-like channels of the OCS, we used P-selectin, which is absent from the former and present in the latter. The other dense granule marker used was granulophysin. Because it is similar, if not identical, with the lysosomal membrane protein CD63,25 it was also found in platelet small granules that have been identified as primary lysosomes. However, their small size and electron dense matrix made them easily distinguishable from the dense granules, which are often located close to the plasma membrane.26 The observation that Gp Ib and IIb-IIIa are present in the dense granule membrane, just as they are present in the alpha -granule membrane (Gp IIb-IIIa immunolabeling being prominent in the dense granules like in alpha -granules and Gp Ib immunolabeling being scanter in both structures),9 shows a close relationship between the limiting membrane of the two types of granules. Although the dense granule-associated pool of glycoproteins only represents a small amount of the total platelet receptor pool (which is mainly expressed by the platelet membrane), the specific localization described here may illuminate the mechanism of formation of these organelles. Indeed, little is known about the constituents of the 5-HT organelle membrane and their synthesis in MK. Our findings might signify that dense granules and alpha -granules share a similar mechanism of formation through an endocytic process originating from the plasma membrane. Indeed, platelet 5-HT originates in the enterochromaffin cells of the intestinal mucosa; it is taken up by circulating platelets and subsequently stored within the dense granules. When platelets are activated, they release 5-HT from storage granules. The precursor cells of platelets, the MK, also have the ability to take up serotonin, although these cells do not synthesize 5-HT.27,28 We show here that Gp Ib and IIb-IIIa expression in dense granules is also an early occuring phenomenon and already well established at the MK stage.

It would be of interest to investigate the content of the dense granule membrane in pathologic states such as storage pool deficiency in which the dense granule membrane is present but its contents are abnormal.29,30 These studies might indicate if there exists a relationship between the presence of receptors in the membrane and the uptake (or retention) of the granule contents. Indeed, as far as alpha -granule abnormalities are concerned, the relationship between the absence of a receptor (Gp IIb-IIIa) in their membrane and the lack of alpha -granule content (fibrinogen) has been well documented in Glanzmann's thrombasthenia.31 Finally, the functional relevance of the receptors Gp IIb-IIIa and Gp Ib in the dense granule membrane might be that, after slight platelet stimulation leading to dense granule secretion only, the exposure of these receptors may help to anchor platelets close to their target to deliver their active transmitters.

In conclusion, we provide ultrastructural and biochemical evidence for the presence of two plasma membrane receptors, Gp IIb-IIIa and Gp Ib, in the dense granules of normal platelets and MKs. We also confirm that P-selectin is a component of the dense granule membrane using a combination of cytochemical and immunogold techniques. These findings suggest that the dense granule membrane, like alpha -granules, may originate from a dual mechanism: direct targeting from the Golgi complex as well as endocytosis from the plasma membrane. The functional relevance of this dense granule-associated pool of glycoproteins remains to be understood.

    FOOTNOTES

   Submitted May 13, 1996; accepted January 3, 1997.
   Supported in part by the Association pour la Recherche contre le Cancer (ARC) and the Fondation pour la Recherche Médicale (FRM).
   Address reprint requests to Elisabeth M. Cramer, MD, PhD, INSERM U.91, Hôpital Henri Mondor, 94010 Créteil, France.

   The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hearly marked ``advertisment'' in accordance with 18 U.S.C. section 1734 solely to indicate this fact.

    ACKNOWLEDGMENT

The authors acknowledge Drs Gaëtan Berger and Anne-Marie Cieutat for helpful comments, Dr Samuel Burstein for carefully editing the English of the manuscript, and Dr Paul-Henri Roméo for his constant support.

    REFERENCES
Abstract
Introduction
Methods
Results
Discussion
References

1. White JG: The dense bodies of human platelets: Inherent electron opacity of the serotonin storage particules. Blood 33:598, 1969[Abstract/Free Full Text]

2. Israels J, Gerrard J, Jacques Y, McNicol A, Cham B, Nishibori M, Bainton DF: Platelet dense granule membrane contain both granulophysin and P-selectin (GMP-140). Blood 80:143, 1992[Abstract/Free Full Text]

3. Cramer EM, Debili N, Martin JF, Gladwin AM, Breton-Gorius J, Harrison P, Savidge GF, Vainchenker W: Uncoordinated expression of fibrinogen compared with thrombospondin and von Willebrand factor in maturing human megakaryocytes. Blood 73:1123, 1989[Abstract/Free Full Text]

4. Roussi J, Drouet L, Sigman J, Vaiman M, Pignaud G, Bonneau M, Massé J-M, Cramer E: Absence of incorporation of plasma von Willebrand factor into porcine platelet alpha -granules. Br J Haematol 90:661, 1995[Medline] [Order article via Infotrieve]

5. Handagama PJ, Shuman MA, Bainton DF: Incorporation of intravenously injected albumin, IgG and fibrinogen in guinea pig megakaryocyte granules. J Clin Invest 84:73, 1989

6. Harrison P, Wilbourn B, Debili N, Vainchenker W, Breton-Gorius J, Lawrie AS, Massé JM, Savidge GF, Cramer EM: Uptake of plasma fibrinogen into the alpha granules of human megakaryocytes and platelets. J Clin Invest 84:1320, 1989

7. Stenberg PE, Mc Ever RP, Shuman MA, Jacques YV, Bainton DF: A platelet alpha -granule membrane protein (GMP-140) is expressed on the plasma membrane after activation. J Cell Biol 101:880, 1985[Abstract/Free Full Text]

8. Cramer EM, Savidge GF, Vainchenker W, Brendt MC, Pidard D, Caen JP, Massé JM, Breton-Gorius J: Alpha-granule pool of glycoprotein IIb-IIIa in normal and pathological platelets and megakaryocytes. Blood 75:1220, 1990[Abstract/Free Full Text]

9. Berger G, Massé J-M, Cramer E: Alpha-granule membrane mirrors the platelet plasma membrane and contains GPIb, IX and V. Blood 87:1385, 1996[Abstract/Free Full Text]

10. Richards JG, Da Prada M: Uraffin reaction: A new cytochemical technique for the localization of adenine nucleotides in organelles storing biogenic amines. J Histochem Cytochem 25:1322, 1977[Abstract]

11. Hatskelzon L, Dalal BL, Shalev A, Robertson C, Gerrard JM: Wide distribution of granulophysin epitopes in granules of human tissues. Lab Invest 68:509, 1993[Medline] [Order article via Infotrieve]

12. Bendayan M: Ultrastructural localization of cytoskeletal proteins in pancreatic secretory cells. Can J Biochem Cell Biol 54:227, 1985

13. Slot JW, Geuze HJ, Gigengack S, Lienhard GE, James DE: Immunolocalization of the insuline regulatable glucose transporter in brown adipose tissue of the rat. J Cell Biol 113:123, 1991[Abstract/Free Full Text]

14. Rendu F, Lebret M, Danielian S, Fagard R, Levy-Toledano S, Fisher S: High PP60c-src level in human platelet dense bodies. Blood 73:1545, 1989[Abstract/Free Full Text]

15. Gerrard J, Lint D, Sims P, Wiedmer T, Fugate R, McMillan E, Robertson C, Israels S: Identification of a platelet dense granule membrane protein that is deficient in a patient with the Hermansky-Pudlak syndrome. Blood 77:101, 1991[Abstract/Free Full Text]

16. Nieuwenhuis HK, Van Oosterhout JJG, Rozemuller E, Van Iwaarden F, Sixma JJ: Studies with a monoclonal antibody against activated platelets: Evidence that a secreted 53,000-molecular weight lysosome like granule protein is exposed on surface of activated platelets in the circulation. Blood 70:838, 1987[Abstract/Free Full Text]

17. Weiss H, Witte L, Kaplan K, Lages B, Chernoff A, Nossel H, Goodman D, Baumgartner H: Heterogeneity in storage pool deficiency: Studies on granule-bound substances in 18 patients including variants deficient in alpha -granules, platelet factor 4, beta -thromboglobulin and platelet-derived growth factor. Blood 54:1296, 1979[Free Full Text]

18. Holmsen H, Weiss HJ: Further evidence for a deficient storage pool of adenine nucleotides in platelets from some patients with thrombocytopathia: `Storage pool disease.' Blood 39:197, 1972

19. Cramer EM, Vainchenker W, Vinci G, Guichard J, Breton-Gorius J: Gray platelet syndrome: Immunoelectron microscopic localization of fibrinogen and von Willebrand factor in platelets and megakaryocytes. Blood 66:1309, 1985[Abstract/Free Full Text]

20. Rendu F, Maclouf J, Boinot C, Levy-Toledano S: Evidence that dense bodies are involved in the alpha-granule liberation from normal and Hermansky-Pudlak syndrome platelets. Thromb Haemost 50:231, 1983

21. Breton-Gorius J, Clezardin P, Guichard J, Debili N, Mamaval L, Vainchenker W, Cramer EM, Delmas P: Localization of platelet osteonectin at the internal face of the alpha-granule membrane in platelets and megakaryocytes. Blood 79:936, 1992[Abstract/Free Full Text]

22. Metzelaar MJ, Heijnen HFG, Sixma JJ, Nieuwenhuis HK: Identification of a 33-kd protein associated with the alpha-granule membrane (GMP-33) that is expressed on the surface of activated platelets. Blood 79:372, 1992[Abstract/Free Full Text]

23. Berger G, Caen JP, Berndt MC, Cramer EM: Ultrastructural demonstration of CD36 in the alpha-granule membrane of human platelets and megakaryocytes. Blood 82:3034, 1993[Abstract/Free Full Text]

24. Cramer EM, Berger G, Berndt MC: Platelet alpha -granule and plasma membrane share two new components: CD9 and PECAM-1. Blood 84:1722, 1994[Abstract/Free Full Text]

25. Nishibori M, Cham B, McNicol A, Shalev A, Jain N, Gerrard J-M: The protein CD63 in platelet dense granules is deficient in patient with Hermansky-Pudlak syndrome and appear identical to granulophysin. J Clin Invest 91:1775, 1993

26. Morimoto T, Ogihara S, Takisawa H: Anchorage of secretion-competent dense granules on the plasma membrane of bovine platelets in the absence of secretory stimulation. J Cell Biol 111:79, 1990[Abstract/Free Full Text]

27. Daimon T, David H: Uptake of 3H-dopamine in megakaryocytes and blood platelets measured by quantitative electron-microscope autoradiography. Histochemistry 85:453, 1986[Medline] [Order article via Infotrieve]

28. Yang M, Srikiatkhachorn A, Anthony M, Chesterman CN, Chong BH: Serotonin uptake, storage and metabolism in megakaryoblasts. Int J Haematol 63:137, 1996

29. Nieuwenhuis HK, Akkerman JWN, Sixma JJ: Patients with a prolonged bleeding time and normal aggregation tests may have storage pool deficiency: Studies on one hundred and six patients. Blood 70:620, 1987[Abstract/Free Full Text]

30. Shalev A, Michaud G, Israels SJ, McNicol A, Singhroy S, McMillan E, White J, Witkop C, Nichols W, Greenberg A, Gerrard J-M: Quantification of a novel dense granule protein (granulophysin) in platelets of patient with dense granule storage pool deficiency. Blood 80:1231, 1992[Abstract/Free Full Text]

31. Handagama P, Scarborough RM, Shuman MA, Bainton DF: Endocytosis of fibrinogen into megakaryocyte and platelet alpha -granules is mediated by alpha IIbbeta 3 (glycoprotein IIb-IIIa). Blood 82:135, 1993[Abstract/Free Full Text]


© 1997 by The American Society of Hematology.

Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
BloodHome page
B. Lo, L. Li, P. Gissen, H. Christensen, P. J. McKiernan, C. Ye, M. Abdelhaleem, J. A. Hayes, M. D. Williams, D. Chitayat, et al.
Requirement of VPS33B, a member of the Sec1/Munc18 protein family, in megakaryocyte and platelet {alpha}-granule biogenesis
Blood, December 15, 2005; 106(13): 4159 - 4166.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
G. Jedlitschky, K. Tirschmann, L. E. Lubenow, H. K. Nieuwenhuis, J. W. N. Akkerman, A. Greinacher, and H. K. Kroemer
The nucleotide transporter MRP4 (ABCC4) is highly expressed in human platelets and present in dense granules, indicating a role in mediator storage
Blood, December 1, 2004; 104(12): 3603 - 3610.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
M. Holtje, S. Winter, D. Walther, I. Pahner, H. Hortnagl, O. P. Ottersen, M. Bader, and G. Ahnert-Hilger
The Vesicular Monoamine Content Regulates VMAT2 Activity through Galpha q in Mouse Platelets. EVIDENCE FOR AUTOREGULATION OF VESICULAR TRANSMITTER UPTAKE
J. Biol. Chem., April 25, 2003; 278(18): 15850 - 15858.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
T. Youssefian, A. Drouin, J.-M. Masse, J. Guichard, and E. M. Cramer
Host defense role of platelets: engulfment of HIV and Staphylococcus aureus occurs in a specific subcellular compartment and is enhanced by platelet activation
Blood, May 13, 2002; 99(11): 4021 - 4029.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
G. L. Reed, M. L. Fitzgerald, and J. Polgar
Molecular mechanisms of platelet exocytosis: insights into the "secrete" life of thrombocytes
Blood, November 15, 2000; 96(10): 3334 - 3342.
[Full Text] [PDF]


Home page
BloodHome page
A. Schmitt, H. Jouault, J. Guichard, F. Wendling, A. Drouin, and E. M. Cramer
Pathologic interaction between megakaryocytes and polymorphonuclear leukocytes in myelofibrosis
Blood, August 15, 2000; 96(4): 1342 - 1347.
[Abstract] [Full Text] [PDF]


Home page
FASEB J.Home page
E. C. DELL’ANGELICA, C. MULLINS, S. CAPLAN, and J. S. BONIFACINO
Lysosome-related organelles
FASEB J, July 1, 2000; 14(10): 1265 - 1278.
[Abstract] [Full Text]


Home page
BloodHome page
T. Youssefian and E. M. Cramer
Megakaryocyte dense granule components are sorted in multivesicular bodies
Blood, June 15, 2000; 95(12): 4004 - 4007.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Pathol.Home page
J. G. White, M. D. Krumwiede, and G. Escolar
Glycoprotein Ib Is Homogeneously Distributed on External and Internal Membranes of Resting Platelets
Am. J. Pathol., December 1, 1999; 155(6): 2127 - 2134.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
O. Peyruchaud, A.T. Nurden, S. Milet, L. Macchi, A. Pannochia, P.F. Bray, N. Kieffer, and F. Bourre
R to Q Amino Acid Substitution in the GFFKR Sequence of the Cytoplasmic Domain of the Integrin alpha IIb Subunit in a Patient With a Glanzmann's Thrombasthenia-Like Syndrome
Blood, December 1, 1998; 92(11): 4178 - 4187.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
C. Poujol, D. T.-L. Roux, P. Tropel, V. Roullot, A. Nurden, G. Marguerie, and P. Nurden
Ultrastructural Analysis of Bone Marrow Hematopoiesis in Mice Transgenic for the Thymidine Kinase Gene Driven by the alpha IIb Promoter
Blood, September 15, 1998; 92(6): 2012 - 2023.
[Abstract] [Full Text] [PDF]


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Right arrow Rights and Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Youssefian, T.
Right arrow Articles by Cramer, E. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Youssefian, T.
Right arrow Articles by Cramer, E. M.
Related Collections
Right arrow Hemostasis, Thrombosis, and Vascular Biology
Social Bookmarking
 Add to CiteULike   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

 click for free articles
home about blood authors subscriptions permissions advertising public access contact us
  Copyright © 1997 by American Society of Hematology         Online ISSN: 1528-0020