1. C1qTNF–related protein-1 (CTRP-1): a vascular wall protein that inhibits collagen-induced platelet aggregation by blocking VWF binding to collagen
by Gerald Lasser, Prasenjit Guchhait, Jeff L. Ellsworth, Paul Sheppard, Ken Lewis, Paul Bishop, Miguel A. Cruz, Jose A. Lopez, and Joachim Fruebis
Blood
Volume 107(2):
January 15, 2006
©2006 by American Society of Hematology

2. CTRP-1 prevents collagen-induced platelet activation and aggregation.
CTRP-1 prevents collagen-induced platelet activation and aggregation. Collagen-induced platelet activation (5 μg/mL collagen I) measured by ATP release (A) and platelet aggregation (B) are inhibited by CTRP-1 (5 μg/mL). The inhibition of platelet aggregation by CTRP-1 is dose dependent (C). For this experiment, PRP was incubated with 1.25 μg/mL collagen I. RU indicates relative units.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology

3. Binding of 125I-CTRP-1 to fibrillar collagen type I
Binding of 125I-CTRP-1 to fibrillar collagen type I. Plates were coated with fibrillar collagen type I and incubated with the indicated concentration of 125I-CTRP-1 in the absence (total binding, •) and presence (nonspecific binding, ○) of 250 μg/mL unlabel...
Binding of 125I-CTRP-1 to fibrillar collagen type I. Plates were coated with fibrillar collagen type I and incubated with the indicated concentration of 125I-CTRP-1 in the absence (total binding, •) and presence (nonspecific binding, ○) of 250 μg/mL unlabeled CTRP-1. Specific binding (▴) was calculated as the difference between the total and nonspecific values. Each point represents the mean of duplicate wells and is representative of 4 separate experiments. Inset shows the Scatchard plot of the specific binding data. B indicates bound 125I-CTRP-1; F, free 125I-CTRP-1.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology

4. CTRP-1 blocks adhesion of platelets on a collagen type I–coated surface at high shear.
CTRP-1 blocks adhesion of platelets on a collagen type I–coated surface at high shear. CTRP-1 does not affect rolling of platelets on a VWF-coated surface. In A and B, citrated whole human blood was incubated with either vehicle alone (A) or with 20 μg/mL CTRP-1 (B) and was perfused over collagen type I–coated coverslips through a flow chamber at 50 dyne/cm2. In C and D, citrated whole human blood was incubated with either vehicle alone (C) or with 20 μg/mL CTRP-1 (D) and was perfused over VWF-coated coverslips through the flow chamber at 50 dyne/cm2. The pictures shown are the initial frames of brief movies (Videos S1-S4; see the Supplemental Videos link at the top of the online article, at the Blood website) and are representative of repeated experiments.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology

5. CTRP-1 blocks intact VWF, VWF A1 domain, and VWF A3 domain binding to fibrillar collagen types I and III under static conditions.
CTRP-1 blocks intact VWF, VWF A1 domain, and VWF A3 domain binding to fibrillar collagen types I and III under static conditions. Plates were coated with collagen type I (▦) or III (▪) and were incubated with vehicle control or CTRP-1 alone, or the indicated mixtures of CTRP-1 with intact VWF (A), VWF A1 domain (B), or VWF A3 domain (C). Each bar represents the mean ± SD of 6 separate measurements. Differences were significant comparing vehicle and VWF alone (*P < .001), A1 domain alone (*P < .001), or A3 domain alone (*P < .02) by an unpaired, 2-tailed Student t test. Differences were significant (**P < .001) relative to incubation with vehicle alone by analysis of variance (ANOVA). OD indicates optical density.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology

6. Cross competition for GPVI-Fc4 and CTRP-1 binding to fibrillar collagen.
Cross competition for GPVI-Fc4 and CTRP-1 binding to fibrillar collagen. Plates were coated with collagen type I as described in “Materials and methods.” (Left) Each well was incubated with 0.3 μg 125I-GPVI-Fc4/mL in the presence or absence of the indicated fold excess of unlabeled GPVI-Fc4 (♦) or CTRP-1 (•). (Right) Each well was incubated with 0.3 μg 125I-CTRP-1/mL in the presence or absence of the indicated fold excess of unlabeled CTRP-1 (•) or GPVI-Fc4 (♦). The 100% values for 125I-GPVI-Fc4 and 125I-CTRP-1 binding in the absence of competitors were 2.87 ± 0.15 and ± 2.11 ng bound/well (mean ± SD, n = 8 separate measurements), respectively. Each point represents the mean ± SD of 4 separate measurements from 2 separate experiments.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology

7. Competition for 125I-GPVI-Fc4 binding to cross-linked CRP by unlabeled GPVI-Fc4 or by CTRP-1.
Competition for 125I-GPVI-Fc4 binding to cross-linked CRP by unlabeled GPVI-Fc4 or by CTRP-1. Plates were coated with CRP and each well was incubated with 0.05 μg/mL 125I-GPVI-Fc4 in the absence or presence of the indicated fold excess of unlabeled GPVI-Fc4 (•) or unlabeled CTRP-1 (○). The 100% values for 125I-GPVI-Fc4 binding in the absence of competitors were 0.94 ± 0.01 ng bound/well. Each point represents the mean of triplicate measurements and is representative of 2 separate experiments.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology

8. CTRP-1 prevents platelet thrombosis in the nonhuman primate Folts vascular injury model and re-establishes and maintains blood flow.
CTRP-1 prevents platelet thrombosis in the nonhuman primate Folts vascular injury model and re-establishes and maintains blood flow. Panels A and B show typical individual flow traces recorded. Treatment with CTRP-1 (0.5 mg/kg) prevents platelet thrombosis and re-establishes blood flow through the injured carotid artery (A). No treatment effect was seen in a BSA-treated control (B). Arrows indicate the time of treatment. (L) The result of the complete study (n = 3, each group; shown is the mean ± SEM). Pretreatment stenotic blood flow was similar in all 3 groups. BSA-treated control animals showed permanent occlusion with no residual blood flow (▪); treatment with 0.5 mg/kg (□) and 1.0 mg/kg CTRP-1 (▦) reestablished blood flow, which was maintained throughout the study. Average blood flow is shown over 2 time intervals: a 30-minute period immediately following cessation of intervention and a subsequent 2-hour time window indicating longer-term effects.
Gerald Lasser et al. Blood 2006;107:
©2006 by American Society of Hematology