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Platelet Lysate (platelet + lysate)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Platelet lysate promotes in vitro wound scratch closure of human dermal fibroblasts: different roles of cell calcium, P38, ERK and PI3K/AKT

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009
Elia Ranzato
Abstract There is a growing interest for the clinical use of platelet derivates in wound dressing. Platelet beneficial effect is attributed to the release of growth factors and other bioactive substances, though mechanisms are mostly unknown. We studied wound-healing processes of human primary fibroblasts, by exposing cells to a platelet lysate (PL) obtained from blood samples. Crystal violet and tetrazolium salt (MTS) assays showed dose,response increase of cell proliferation and metabolism. In scratch wound and transwell assays, a dose of 20% PL induced a significant increase of wound closure rate at 6 and 24 hrs, and had a strong chemotactic effect. BAPTA-AM, SB203580 and PD98059 caused 100% inhibition of PL effects, whereas wortmannin reduced to about one third the effect of PL on wound healing and abolished the chemotactic response. Confocal imaging showed the induction by PL of serial Ca2+ oscillations in fibroblasts. Data indicate that cell Ca2+ plays a fundamental role in wound healing even without PL, p38 and ERK1/2 are essential for PL effects but are also activated by wounding per se, PI3K is essential for PL effects and its downstream effector Akt is activated only in the presence of PL. In conclusion, PL stimulates fibroblast wound healing through the activation of cell proliferation and motility with different patterns of involvement of different signalling pathways. [source]

Vinculin is proteolyzed by calpain during platelet aggregation: 95 kDa cleavage fragment associates with the platelet cytoskeleton

CYTOSKELETON, Issue 4 2004
Katherine Serrano
Abstract The focal adhesion protein vinculin contributes to cell attachment and spreading through strengthening of mechanical interactions between cell cytoskeletal proteins and surface membrane glycoproteins. To investigate whether vinculin proteolysis plays a role in the influence vinculin exerts on the cytoskeleton, we studied the fate of vinculin in activated and aggregating platelets by Western blot analysis of the platelet lysate and the cytoskeletal fractions of differentially activated platelets. Vinculin was proteolyzed into at least three fragments (the major one being ,95 kDa) within 5 min of platelet activation with thrombin or calcium ionophore. The 95 kDa vinculin fragment shifted cellular compartments from the membrane skeletal fraction to the cortical cytoskeletal fraction of lysed platelets in a platelet aggregation-dependent manner. Vinculin cleavage was inhibited by calpeptin and E64d, indicating that the enzyme responsible for vinculin proteolysis is calpain. These calpain inhibitors also inhibited the translocation of full-length vinculin to the cytoskeleton. We conclude that cleavage of vinculin and association of vinculin cleavage fragment(s) with the platelet cytoskeleton is an activation response that may be important in the cytoskeletal remodeling of aggregating platelets. Cell Motil. Cytoskeleton 58:242,252, 2004. © 2004 Wiley-Liss, Inc. [source]

Platelet lysate promotes in vitro wound scratch closure of human dermal fibroblasts: different roles of cell calcium, P38, ERK and PI3K/AKT

Diversity of Glanzmann thrombasthenia in southern India: 10 novel mutations identified among 15 unrelated patients

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2006
E. J. R. NELSON
Summary.,Background: Glanzmann thrombasthenia (GT) is a congenital bleeding disorder caused by either a lack or dysfunction of the platelet integrin ,IIb,3. Objectives: To determine the molecular basis of GT in patients from southern India. Patients: Fifteen unrelated patients whose diagnosis was consistent with GT were evaluated. Results: Platelet surface expression of ,IIb,3 was < 10%, 10%,50%, and > 50% of controls in five, nine, and one patient(s), respectively. Immunoblotting of the platelet lysates showed no ,IIb in 14 patients, and no ,3 in 10 patients, although severely reduced in four patients. Platelet fibrinogen was undetectable in 13 patients, and severely reduced in one patient. One patient showed normal surface ,IIb,3 expression, and normal ,IIb, ,3 and fibrinogen levels in the lysate. Ten novel candidate disease-causing mutations were identified in 11 patients. The missense mutations included Gly128Ser, Ser287Leu, Gly357Ser, Arg520Trp, Leu799Arg in ,IIb, and Cys575Gly in ,3. We have already shown that Gly128Ser, Ser287Leu, and Gly357Ser mutations variably affect ,IIb,3 surface expression. The Cys575Gly mutation may disrupt the disulphide link with Cys586 to cause the GT phenotype. The molecular pathology of the other missense mutations is not clear. Two nonsense mutations, Trp-16Stop and Glu715Stop in ,IIb, and a 7-bp deletion (330-336TCCCCAG) in ,3 are predicted to result in truncated proteins. An IVS15(,1)G , A mutation in ,IIb induced a cryptic splice site as confirmed by reverse transcription-polymerase chain reaction (RT-PCR) analysis. Thirteen polymorphisms were also identified (five in ,IIb and eight in ,3), among which five were novel. Conclusions: While identifying a significant number of novel mutations causing GT, this study confirms the genetic heterogeneity of the disorder in southern India. [source]