Notch signaling functions in noncanonical juxtacrine manner in platelets to amplify thrombogenicity

  1. Susheel N Chaurasia
  2. Mohammad Ekhlak
  3. Geeta Kushwaha
  4. Vipin Singh
  5. Ram L Mallick
  6. Debabrata Dash  Is a corresponding author
  1. Center for Advanced Research on Platelet Signaling and Thrombosis Biology, Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, India
7 figures, 2 videos, 2 tables and 2 additional files

Figures

Figure 1 with 2 supplements
Human platelets express Notch1 and DLL-4.

(A) Immunoblot demonstrating expression of Notch1 in platelets pre-treated with or without puromycin (Puro, 10 mM), followed by stimulation with thrombin (Thr, 1 U/ml, for 5 min at 37 °C). (B) Corresponding densitometric analysis of Notch1 normalised with β-actin (n=5). (C) Flow cytometric analysis of platelets treated with (unshaded) or without (shaded) thrombin (1 U/ml) for 5 min at 37 °C, followed by staining with anti-Notch1 antibody and Alexa Fluor 488-labelled secondary antibody. (D) Corresponding mean fluorescence intensity (MFI) of Notch1 expression on platelets as indicated (n=3). (E) Immunoblot showing synthesis of DLL-4 in thrombin-stimulated platelets. (F) Corresponding densitometric analysis of DLL-4 normalised with β-actin (n=9). (G) Histogram showing expression of DLL-4 on surface of human platelets pre-treated with (unshaded) or without (shaded) thrombin (1 U/ml) for 5 min at 37 °C, followed by incubation with anti-DLL-4 antibody and Alexa Fluor 488-labelled secondary antibody. (H) Corresponding mean fluorescence intensity of DLL-4 expression on platelets as indicated (n=4). Data are presented as mean ± SEM of at least three different experiments. Analyzed by either Student’s paired t-test (D and H) or RM one-way ANOVA with Dunnett’s multiple comparisons test (B and F).

Figure 1—figure supplement 1
Human platelets abundantly express NOTCH1 mRNA.

Amplification chart (A) and dot plot (B) representing Cq of mRNAs in platelets as indicated. (C) Melt peak analysis to rule out formation of by-products during amplification reactions. Figures are representative of seven individual experiments (n=7). Data are presented as mean ± SEM.

Figure 1—figure supplement 2
Human platelets abundantly express DLL4 mRNA.

(A and B) Amplification chart and dot plot, respectively, representing Cq of mRNAs in platelets as indicated. (C) Melt peak analysis indicative of lack of formation of by-products during amplification reactions. Figures are representative of seven individual experiments (n=7). Data are presented as mean ± SEM.

Expression of NICD in human platelets.

(A) Immunoblot showing expression of NICD in DLL-4 (15 µg/ml for 10 min)-treated platelets in absence or presence of either DAPT (10 µM) or DBZ (10 µM) or vehicle. (B) Corresponding densitometric analysis of NICD normalised with β-actin (n=6). (C, D and E) Immunoblot of NICD expression in either stored or A23187 (1 µM)-treated platelets under conditions as indicated. Data are represented as mean ± SEM of at least three individual experiments and analyzed by RM one-way ANOVA with Dunnett’s multiple comparisons test.

Figure 3 with 3 supplements
DLL-4 induces integrin activation, P-selectin externalization, ATP release, extracellular vesicle shedding, rise in intracellular Ca2+ and increase in tyrosine phosphoproteome in human platelets.

(A and C) Histograms showing binding of PAC-1 (A) and anti-P-selectin antibody (C) to platelets pre-incubated with either DAPT (10 µM) or vehicle for 10 min at RT followed by treatment with either DLL-4 (15 µg/ml) or DLL-1 (15 µg/ml) for 10 min, or with thrombin (Thr, 1 U/ml) for 5 min at 37 °C as indicated. (B and D) Ccorresponding mean fluorescence intensities of PAC-1 (n=12) and anti-P-selectin antibody (n=9) binding to platelets, respectively. (E) Bar diagram representing ATP secretion from platelet dense granules pre-incubated with either DAPT (10 µM) or vehicle for 10 min at RT followed by treatment with DLL-4 for 10 min (n=4). (F) Fura-2-loaded platelets were pre-treated for 5 min either with calcium (1 mM) or EGTA (1 mM) followed by incubation with DLL-4 (15 µg/ml) for 15 min and intracellular Ca2+ was measured. (G) Corresponding bar diagram representing mean concentration of intracellular Ca2+ over 300 sec of measurement (n=5). (H) Platelets were pre-treated with either DAPT (10 µM) or DBZ (10 µM) or vehicle for 10 min at RT followed by treatment with DLL-4 (15 µg/ml) for 10 min at RT. PEVs were isolated and analyzed with Nanoparticle Tracking Analyzer (n=8). (I) Immunoblot showing profile of tyrosine phosphorylated proteins in platelets pre-treated with either DAPT (10 µM) or DBZ (10 µM) or vehicle for 10 min at RT followed by treatment with either DLL-4 (15 µg/ml) for 10 min at RT or DLL-1 (15 µg/ml) for 10 min at RT or with thrombin (1 U/ml) for 5 min at 37 °C as indicated (n=4). Arrows indicate position of peptides whose intensity increased in presence of DLL-4. (J and L) Immunoblots showing expression of p-PI3K and pAKT in DLL-4 (15 µg/ml for 10 min)-treated platelets in absence or presence of either DAPT (10 µM) or vehicle. (K and M) Corresponding densitometric analyses normalised with PI3K (n=3) and AKT (n=7), respectively. Data are presented as mean ± SEM of at least three different experiments. Results were analyzed by RM one-way ANOVA with either Dunnett’s multiple comparisons test (E, H, K and M) or Sidak’s multiple comparisons test (B, D and G).

Figure 3—figure supplement 1
DLL-4 induces fibrinogen binding to human platelets.

(A) Histogram showing binding of Alexa Fluor 488-labelled fibrinogen (10 µg/ml) to platelets pre-incubated with either DAPT (10 µM) or vehicle for 10 min at RT followed by treatment with either DLL-4 (15 µg/ml) or DLL-1 (15 µg/ml) for 10 min, or with thrombin (1 U/ml) for 5 min at 37 °C as indicated. (B) Corresponding mean fluorescence intensity of fibrinogen binding to platelets presented as mean ± SEM. Data are representative of nine (n=9) different experiments-and analysed by RM one-way ANOVA with Sidak’s multiple comparisons test.

Figure 3—figure supplement 2
DLL-4 induces platelet-leukocyte aggregate formation.

(A and B) Flow cytometric analysis of platelet-neutrophil aggregates (A) and platelet-monocyte aggregates (B) in whole blood stained with anti-CD41a-APC (specific for platelets) and anti-CD14-FITC (specific for neutrophils/monocytes) followed by treatment with DLL-4 (15 µg/ml) in presence or absence of DAPT (40 µM), as indicated. C (n=8) and D (n=8), corresponding bar diagrams quantifying mean percent platelet-neutrophil and platelet-monocyte aggregates, respectively. Data are representative of eight different experiments and presented as mean ± SEM. Analysed by RM one-way ANOVA with Dunnett’s multiple comparisons test.

Figure 3—figure supplement 3
Inhibitors of PI3K and PKC prevent PAC-1 binding to DLL-4-induced human platelets.

(A) Histogram shows PAC-1-FITC binding to platelets pre-incubated with either LY-294002 (80 µM) or Ro-31–8425 (20 µM) or vehicle for 10 min at RT followed by exposure to DLL-4 (15 µg/ml) for 10 min at RT. (B) Corresponding mean fluorescence intensity of four (n=4) different experiments representing PAC-1 binding. Data are presented as as mean ± SEM and analysed by RM one-way ANOVA with Sidak’s multiple comparisons test.

Figure 4 with 1 supplement
DLL-4 operates in a juxtacrine manner to potentiate thrombin-mediated platelet activation.

(A) Aggregation of washed human platelets induced by thrombin (Thr, 0.1 U/ml) either in presence of vehicle (tracing 1) or DLL-4 (15 µg/ml, tracing 2). Tracing 3 represents cells pre-incubated with DAPT (20 µM) for 10 min at RT followed by addition of DLL-4 and thrombin. (B) Corresponding bar chart representing mean platelet aggregation (n=5). (C and E) Histograms representing PAC-1 binding (C) and surface expression of P-selectin (E) in platelets pre-treated with DLL-4 (7.5 µg/ml) for 10 min followed by stimulation with thrombin (0.1 U/ml) as indicated. Tracings 4 of C and E represent cells pre-incubated with DAPT (10 µM) for 10 min at RT followed by addition of DLL-4 and thrombin. (D and F) corresponding mean fluorescence intensity of PAC-1 binding (n=9) and surface expression of P-selectin (n=10), respectively. (G) Aggregation of washed human platelets induced by thrombin (0.1 U/ml) following pre-treatment with either rabbit-IgG (20 µg/ml) for 5 min (tracing 2), or anti-DLL-4 antibody (20 µg/ml) for 5 min (tracing 3) or vehicle (tracing 1). (H) Corresponding bar chart representing mean platelet aggregation (n=4). (I) Platelets were pre-treated with either anti-DLL-4 antibody (20 µg/ml) or rabbit IgG (20 µg/ml) or vehicle for 5 min at RT followed by aggregation induced by thrombin (0.1 U/ml) for 5 min at 37°C. EVs were isolated from aggregated platelets and analyzed with Nanoparticle Tracking Analyzer (n=3). Data are representative of at least three different experiments and presented as mean ± SEM. Analyzed by RM one-way ANOVA with either Dunnett’s multiple comparisons test (B, H, and I) or Sidak’s multiple comparisons test (D and F).

Figure 4—figure supplement 1
Anit-DLL-4 antibody inhibits thrombin-mediated platelet aggregation in a dose-dependent manner.

(A) Thrombin (0.1 U/ml)-induced aggregation of washed human platelets pre-incubated for 5 min with either rabbit-IgG (10 µg/ml) (tracing 1), or anti-DLL-4 antibody (2, 5, and 10 µg/ml) (tracings 2, 3, and 4, respectively). (B) Corresponding bar chart representing mean platelet aggregation (n=3). Data are presented as mean ± SEM.

Figure 5 with 4 supplements
Inhibition of γ-secretase attenuates agonist-induced platelet responses.

(A, C and E) Aggregation of washed human platelets induced by thrombin (Thr, 0.25 U/ml), TRAP (2.5 µM), or collagen (Coll, 2.5 µg/ml) in absence (tracing 1) or presence (tracing 2) of DAPT (20 µM) recorded as percent light transmitted. Tracings 3 and 4 in panel A represent secretion of ATP from thrombin-stimulated platelets either in absence or presence of DAPT, respectively. (G and I) Platelet aggregation in whole blood induced by either TRAP (2 µM) or collagen (2 µg/ml) in absence (tracing 1) or presence (tracing 2) of DAPT (40 µM) recorded as change in electrical resistance (impedance). B (n=7), D (n=5), F (n=3), H (n=3), and J (n=3), corresponding bar chart representing mean platelet aggregation. K, bar diagram representing mean ATP secretion from platelet dense granules (n=4). (L and N) Flow cytometric analysis of platelet-neutrophil aggregates (L) and platelet-monocyte aggregates (N) in whole blood stained with anti-CD41a-APC (specific for platelets) and anti-CD14-FITC (specific for neutrophils/monocytes) followed by treatment with TRAP (2 µM) in presence or absence of DAPT (40 µM), as indicated. Amorphous gates were drawn for monocyte (high fluorescence and low SSC) and neutrophil (low fluorescence and high SSC) populations. M (n=8) and O (n=9), bar diagrams showing percentage of platelet-neutrophil and platelet-monocyte aggregate formation, respectively. Data are representative of at least three different experiments and presented as mean ± SEM. Analyzed by either Student’s paired t-test (B, D, F, H, J, and K) or RM one-way ANOVA with Dunnett’s multiple comparisons test (M and O).

Figure 5—figure supplement 1
Inhibition of γ-secretase attenuates thrombin-induced platelet aggregation.

(A) Aggregation of washed human platelets induced by thrombin (Thr, 0.25 U/ml), in absence (tracing 1) or presence (tracing 2) of DBZ (30 µM) recorded as percent light transmitted. (B) Corresponding bar chart representing mean platelet aggregation (n=8). Data are presented as mean ± SEM and analysed by Student’s paired t-test.

Figure 5—figure supplement 2
Inhibition of γ-secretase attenuates thrombin-induced integrin activation.

(A, C, E and G) Histograms representing binding of PAC-1 (A and C) and fibrinogen (E and G) to platelets pre-treated with DAPT (10 µM) for 10 min, followed by treatment with thrombin (0.1, 0.5, or 1 U/ml) for 5 min as indicated. B (n=7), D (n=8), F (n=9), and H (n=5), bar diagrams representing corresponding mean fluorescence intensities for binding of PAC-1 (B and D) and fibrinogen (F and H), respectively. Data are representative of at least five different experiments and presented as mean ± SEM. Analysed by RM one-way ANOVA with Dunnett’s multiple comparisons test.

Figure 5—figure supplement 3
Inhibition of γ-secretase attenuates thrombin-induced P-selectin externalization.

(A and C) Histograms representing surface expression of P-selectin in platelets pre-treated with DAPT (10 µM) for 10 min followed by treatment with thrombin (0.1 or 1 U/ml) for 5 min at 37 °C ͦ as indicated. B (n=9) and D (n=6), bar diagram representing corresponding mean fluorescence intensity of surface expression of P-selectin. Data are representative of at least six different experiments and presented as mean ± SEM. Analysed by RM one-way ANOVA with Dunnett’s multiple comparisons test.

Figure 5—figure supplement 4
Inhibition of γ-secretase attenuates thrombin-induced extracellular vesicle release form human platelets.

Platelets were pre-treated with either DAPT (10 µM) or vehicle for 10 min at RT followed by treatment with thrombin (Thr, 1 U/ml) for 5 min at 37 °C. ͦ PEVs were isolated and analysed with Nanoparticle Tracking Analyzer (n=3). Data are presented as mean ± SEM and analysed by RM one-way ANOVA with Dunnett’s multiple comparisons test.

Figure 6 with 1 supplement
Inhibition of γ-secretase precludes arterial thrombosis in mice and platelet thrombus generation in ex vivo.

(A) Representative time-lapse images showing mesenteric arteriolar thrombosis in mice, pre-administered with either vehicle (control) or DAPT (50 mg/kg) captured 5, 10, 15 or 20 min after ferric chloride-induced injury of the mesenteric arterioles. (B-D) Bar diagrams showing time to first thrombus formation (B), thrombus growth rate (C) and time to occlusion (D) (n=8). (E) Representative image of platelet accumulation after 5 min of perfusion of human platelets pre-treated with either DAPT (20 µM) or vehicle. (F) Corresponding bar diagram representing average surface area covered by platelet thrombi after 5 min of perfusion on collagen matrix (n=4). (G) Thromboelastogram of kaolin-stimulated citrated whole blood pre-incubated with (green tracing) or without DAPT (black tracing). (H and I) Bar diagram representing reaction time (R) and maximum amplitude (MA) of the clot, respectively (n=5). Data are representative of at least four individual experiments and presented as mean ± SEM. Analyzed by either unpaired (B and C) or paired (F, H, and I) Student’s t-test (unpaired for in vivo and paired for in vitro and ex vivo).

Figure 6—figure supplement 1
Kaplan-Meier curve representing percent of occluded mesenteric arteries at varying time points in mice pre-administered with either vehicle (control) or DAPT (50 mg/kg), as indicated (n=8).
Scheme depicting the role of Notch signaling in potentiating agonist-induced platelet stimulation.

Juxtacrine interaction between DLL-4 and Notch1 expressed on surfaces of agonist-stimulated platelets that remain in close proximity within platelet aggregates, leading to potentiation of thrombin signaling and consolidation of thrombus. The juxtacrine responses are blocked by employing either anti-DLL-4 antibody (blocking antibody) or inhibitors of γ-secretase.

Videos

Video 1
Ferric chloride-induced mesenteric arteriolar thrombosis in mice pre-administered with DAPT (50 mg/kg).

Platelets were fluorescently labelled with DyLight 488 anti-GPIbβ antibody (0.1 µg/g body weight).

Video 2
Ferric chloride-induced mesenteric arteriolar thrombosis in mice pre-administered with vehicle (control).

Platelets were fluorescently labelled with DyLight 488 anti-GPIbβ antibody (0.1 µg/g body weight).

Tables

Key resources table
Reagent type (species) or resourceDesignationSource or referenceIdentifiersAdditional information
AntibodyRabbit monoclonal anti-Notch1Cell Signaling Technology4380WB 1:1000
FC 1:100
AntibodyRabbit polyclonal anti-DLL4Novus BiologicalsNB600 892WB 1:1000
FC 1:500
Aggregation 2–20 µg/ml
AntibodyRabbit monoclonal anti- cleaved Notch1Cell Signaling Technology4147WB 1:1000
AntibodyMouse monoclonal anti-phospho(Ser473)-AKTCell Signaling Technology4051WB 1:1000
AntibodyRabbit polyclonal anti-AKTCell Signaling Technology9272WB 1:1000
AntibodyRabbit polyclonal anti-phospho( Tyr467)-PI3KElabscienceE-AB-20966WB 1:1000
AntibodyMouse monoclonal anti-PI3KSanta Cruz Biotechnologysc-1637WB 1:500
AntibodyMouse monoclonal anti-p-TyrSanta Cruz Biotechnologysc-7020WB 1:5000
AntibodyRabbit polyclonal anti-actinSigma-AldrichA2066WB 1:5000
AntibodyPE-Mouse anti-human CD62PBD Biosciences5505615 µl
AntibodyFITC-Mouse anti-human PAC-1BD Biosciences3405075 µl
AntibodyFITC-Mouse anti-human CD14BD Biosciences55539710 µl
AntibodyAPC-Mouse anti-human CD41aBD Biosciences55977710 µl
AntibodyDyLight 488-Rat anti-mouse GPIbβEmfret AnalyticsX4880.1 µg/g body weight
AntibodyIgG from rabbit serumSigma-AldrichI500610–20 µg/ml
AntibodyAlexa Fluor 488-Goat anti-rabbit IgGInvitrogenA110081:100 (Notch1)
1:200 (DLL-4)
AntibodyHRP-Goat anti-rabbit IgGBangalore Genei114038001 ASee Methods- Western analysis
AntibodyHRP-Goat anti-mouse IgGBangalore Genei114068001 ASee Methods- Western analysis
Peptide, recombinant proteinDLL-1Sino Biological11635-H08H15 µg/ml
Peptide, recombinant proteinDLL-4Sino Biological10171-H02H7.5–15 µg/ml
Peptide, recombinant proteinThrombin receptor-activating peptide (TRAP)Sigma-AldrichS18202–2.5 µM
Peptide, recombinant proteinBovine serum albumin (BSA)VWR Life Science0332–500 G
Peptide, recombinant proteinThrombinSigma-AldrichT68840.1–1 U/ml
Peptide, recombinant proteinCollagenChrono-log3852–2.5 µg/ml
Chemical compound/InhibitorN-(N-(3, 5-difluorophenacetyl)-L-alanyl)-S-phenyl-glycine t-butyl ester (DAPT)Sigma-AldrichD594210–40 µM
Chemical compound/InhibitorDibenzazepine (DBZ)SelleckchemYO-0102710–30 µM
Chemical compound/InhibitorLY-294002Sigma-AldrichL990880 µM
Chemical compound/InhibitorRo-31–8425Calbiochem55751420 µM
Chemical compound/InhibitorPuromycinCalbiochem54022210 mM
Chemical compound/InhibitorProstaglandin E1Sigma-AldrichP5515
Chemical compound/reagentDimethyl sulfoxide (DMSO)Sigma-AldrichD5879
Chemical compound/reagentDiethylpyrocarbonate (DEPC)AmrescoE174
Chemical compound/reagentEthylene glycol tetraacetic acid (EGTA)Sigma-AldrichE-4378
Chemical compound/reagentEthylenediaminetetraacetic acid (EDTA)Sigma-AldrichE9884
Chemical compound/reagentMnCl2Sigma-AldrichM3634
Chemical compound/reagentXylazineSigma-AldrichX1251
Chemical compound/reagentKaolinHaemonetics6300
Commercial assay or KitCell Titer-Glo Luminescent Cell Viability Assay KitPromegaG7570
Commercial assay or KitChrono-lume luciferin luciferase reagentChrono-log395
Commercial assay or KitHigh-capacity reverse transcription kitApplied Biosystems4368814
OtherCalcein AMInvitrogenC3100MPCell-permeable dye (2 µg/ml)
OtherFura-2 AMCalbiochem344905Cell-permeable dye (2 µM)
OtherSYBR Green SuperMixBio-Rad170–8882Dye; see Methods- Quantitative Real-Time PCR
OtherTRIzolInvitrogen15596026See Methods- RNA extraction
OtherFibrinogen (Alexa Fluor 488-conjugated)InvitrogenF1319110 µg/ml
OtherPolyvinylidene fluoride (PVDF) membraneMilliporeIPVH00010See Methods- Western analysis
OtherImmobilon western chemiluminescent HRP substrateMilliporeWBKLS0100See Methods- Western analysis
OtherBD FACS Lysing SolutionBD Biosciences349202See Methods- Study of platelet-leukocyte interaction
OtherRestore Western blot stripping bufferThermo Fisher Scientific21059See Methods- Western analysis
OtherSkimmed milk powderMillipore70166See Methods- Western analysis
Table 1
Details of primers employed in amplification reactions.
GenesForward Primers (5’ to 3’)Reverse Primers (5’ to 3’)Amplicon Size (bp)Annealing Temp (°C)
GAPDHGAAGGTGAAGGTCGGAGTCGAAGATGGTGATGGGATTTC22657
ACTBAAATCTGGCACCACACCTTCAGCACAGCCTGGATAGCAAC16059
NOTCH1TCAGCGGGATCCACTGTGAGACACAGGCAGGTGAACGAGTTG10462
NOTCH2TGCCAAGCTCAGTGGTGTTGTATGCTAGGCTTTGTGGGATTCAG13260
NOTCH3GGTTCCCAGTGAGCACCCTTACGTGGATTCGGACCAGTCTGAGAG10060
NOTCH4CGGCCTCGGACTCAGTCACAACTCCATCCTCATCAACTTCTG11260
DLL1TGTGTGACGAACACTACTACGGAGGTGAAGTGGCCGAAGGCA7665
DLL3GAGACACCCAGGTCCTTTGACAGTGGCAGATGTAGGCAGA6165
DLL4CCAGGAAAGTTTCCCCACAGTCCGACACTCTGGCTTTTCACT8265
JAG1GCTGGCAAGGCCTGTACTGACTGCCAGGGCTCATTACAGA7865
JAG2CACCGAGGTCAAGGTGGAGAACGCTGAAGGCACCACACA8465

Additional files

Supplementary file 1

Thromboelastogram of kaolin-stimulated citrated whole blood pre-treated with or without DAPT.

Data are representative of five individual experiments and presented as mean ± SEM, analyzed by Student’s paired t-test.

https://cdn.elifesciences.org/articles/79590/elife-79590-supp1-v2.docx
MDAR checklist
https://cdn.elifesciences.org/articles/79590/elife-79590-mdarchecklist1-v2.docx

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  1. Susheel N Chaurasia
  2. Mohammad Ekhlak
  3. Geeta Kushwaha
  4. Vipin Singh
  5. Ram L Mallick
  6. Debabrata Dash
(2022)
Notch signaling functions in noncanonical juxtacrine manner in platelets to amplify thrombogenicity
eLife 11:e79590.
https://doi.org/10.7554/eLife.79590