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Studies have discovered that different extracts of Evodia rutaecarpa and its phytochemicals show a variety of biological activities associated with inflammation. Although rutaecarpine, an alkaloid isolated from the unripe fruit of E. rutaecarpa, has been exposed to have anti-inflammatory properties, the mechanism of action has not been well studied. Thus, this study investigated the molecular mechanisms of rutaecarpine (RUT) in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. RUT reserved the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukin (IL)-1β in the LPS-induced macrophages. RUT showed an inhibitory effect on the mitogen-activated protein kinases (MAPKs), and it also inhibited nuclear transcription factor kappa-B (NF-κB) by hindering IκBα and NF-κB p65 phosphorylation and p65 nuclear translocation. The phospho-PI3K and Akt was concentration-dependently suppressed by RUT. However, RUT not only suggestively reduced the migratory ability of macrophages and their numbers induced by LPS but also inhibited the phospho-Src, and FAK. Taken together, these results indicate that RUT participates a vital role in the inhibition of LPS-induced inflammatory processes in RAW 264.7 macrophages and that the mechanisms involve PI3K/Akt and MAPK-mediated downregulation of NF-κB signaling pathways. Notably, reducing the migration and number of cells induced by LPS via inhibiting of Src/FAK pathway was also included to the anti-inflammatory mechanism of RUT. Therefore, RUT may have potential benefits as a therapeutic agent against chronic inflammatory diseases.

Platelets are crucial for hemostasis and arterial thrombosis, which may lead to severe cardiovascular diseases (CVDs). Thus, therapeutic agents must be developed to prevent pathological platelet activation. Glabridin, a major bioalkaloid extracted from licorice root, improves metabolic abnormalities (i.e., obesity and diabetes) and protects against CVDs and neuronal disorders. To the best of our knowledge, no studies have focused on glabridin’s effects on platelet activation. Therefore, we investigated these effects in humans and mice. Glabridin exhibited the highest inhibitory effects on collagen-stimulated platelet aggregation and moderate effects on arachidonic-acid-stimulated activation; however, no effects were observed for any other agonists (e.g., thrombin or U46619). Glabridin evidently reduced P-selectin expression, ATP release, and intracellular Ca2+ ([Ca2+]i) mobilization and thromboxane A2 formation; it further reduced the activation of phospholipase C (PLC)γ2/protein kinase C (PKC), phosphoinositide 3-kinase (PI3K)/Akt/glycogen synthase kinase-3β (GSK3β), mitogen-activated protein kinase (MAPK), and NF-κB. In mice, glabridin reduced the mortality rate caused by acute pulmonary thromboembolism without altering bleeding time. Thus, glabridin effectively inhibits the PLCγ2/PKC cascade and prevents the activation of the PI3K/Akt/GSK3β and MAPK pathways; this leads to a reduction in [Ca2+]i mobilization, which eventually inhibits platelet aggregation. Therefore, glabridin may be a promising therapeutic agent for thromboembolic disorders.

Metformin is widely used as first-line medication for type 2 diabetes (T2D), the main disease comorbid with kidney disease, cardiovascular diseases (CVDs), and retinopathy. Platelets are crucial in platelet-dependent arterial thrombosis, which causes CVDs and cerebrovascular diseases. Research indicates that metformin may improve these diseases; metformin reportedly reduced platelet activation in rats. However, no reports have included human platelets. We investigated the mechanisms underlying metformin’s effects on platelet activation by using human platelets and evaluated its in vivo effectiveness in experimental mice. Metformin inhibited platelet aggregation stimulated by collagen but not by arachidonic acid, U46619, or thrombin. Metformin suppressed ATP release, [Ca2+]i mobilization, and P-selectin expression, as well as phospholipase C (PLC)γ2/protein kinase C (PKC), p38 mitogen-activated protein kinase (MAPK), and phosphoinositide 3-kinase (PI3K)/Akt/glycogen synthase kinase-3β (GSK3β) phosphorylation. Metformin did not affect vasodilator-stimulated phosphoprotein (VASP) phosphorylation. In the animal studies, metformin reduced acute pulmonary thromboembolism mortality without increasing bleeding times. These results provide insights into the role and mechanisms of metformin in human platelet activation. Metformin decreased platelet activation by interfering with the PLCγ2/PKC, PI3K/Akt/GSK3β, and p38 MAPK pathways through a VASP-independent mechanism. Metformin demonstrates promise as a new class of antiplatelet agent that can inhibit platelet activation.

The role of activated platelets in acute and chronic cardiovascular diseases (CVDs) is well established. Therefore, antiplatelet drugs significantly reduce the risk of severe CVDs. Evodia rutaecarpa (Wu-Chu-Yu) is a well-known Chinese medicine, and rutaecarpine (Rut) is a main bioactive component with substantial beneficial properties including vasodilation. To address a research gap, we investigated the inhibitory mechanisms of Rut in washed human platelets and experimental mice. At low concentrations (1–5 μM), Rut strongly inhibited collagen-induced platelet aggregation, whereas it exerted only a slight or no effect on platelets stimulated with other agonists (e.g., thrombin). Rut markedly inhibited P-selectin expression, adenosine triphosphate release, [Ca2+]i mobilization, hydroxyl radical formation, and phospholipase C (PLC)γ2/protein kinase C (PKC), mitogen-activated protein kinase, and phosphoinositide 3-kinase (PI3K)/Akt/glycogen synthase kinase-3β (GSK3β) phosphorylation stimulated by collagen. SQ22536 (an adenylate cyclase inhibitor) or ODQ (a guanylate cyclase inhibitor) did not reverse Rut-mediated antiplatelet aggregation. Rut was not directly responding to vasodilator-stimulated phosphoprotein phosphorylation. Rut significantly increased the occlusion time of fluorescence irradiated thrombotic platelet plug formation. The findings demonstrated that Rut exerts a strong effect against platelet activation through the PLCγ2/PKC and PI3K/Akt/GSK3β pathways. Thus, Rut can be a potential therapeutic agent for thromboembolic disorders.

Inflammation is the primary biological reaction to induce severe infection or injury in the immune system. Control of different inflammatory cytokines, such as nitric oxide (NO), interleukins (IL), tumor necrosis factor alpha-(TNF-α), noncytokine mediator, prostaglandin E2 (PGE2), mitogen activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB), facilitates anti-inflammatory effect of different substances. Coordination metal complexes have been applied as metallo-drugs. Several metal complexes have found to possess potent biological activities, especially anticancer, cardioprotective, chondroprotective and anti-parasitosis activities. Among the metallo drugs, ruthenium-based (Ru) complexes have paid much attention in clinical applications. Despite the kinetic nature of Ru complexes is similar to platinum in terms of cell division events, their toxic effect is lower than that of cisplatin. This paper reviews the anti-inflammatory effect of novel synthetic Ru complexes with potential molecular mechanisms that are actively involved.

Pterostilbene (PTE), a natural stilbenoid occurring in grapes and berries, is recognized as a dimethylated analogue of resveratrol. This compound shows numerous notable pharmacological activities, including antiaging, anticancer, antidiabetes, antioxidant, and neuroprotection. This study investigates the anti-inflammatory properties of PTE in macrophage cells (RAW 264.7) against the lipoteichoic acid (LTA) stimulation. The expression of inflammatory tumor necrosis factor (TNF-α), interleukin-1β (IL-1 β), and inducible nitric oxide synthase (iNOS) and the content of nitric oxide (NO) were detected in LTA-induced cells. In addition, a Western blot assay was used to detect mitogen-activated protein kinases: extracellular signal-regulated kinase (ERK)1/2, p38 MAPK, and c-Jun N-terminal kinase (JNK). The phosphorylation of IκB and p65 and translocation of nuclear factor kappa B (NF-κB) were assessed by Western blot and immuno-fluorescence staining. The results showed that PTE significantly attenuated NO production and TNF-α, IL-1 β, and iNOS expression in LTA stimulated cells. Among the activation of ERK, JNK, and p38 in cells treated with LTA, PTE at higher concentration had only inhibited ERK activation. However, PTE blocked IκB phosphorylation, phosphorylation and nuclear translocation of p65NF-κB. Fascinatingly, PTE enhanced antioxidant defense molecules as verified by the enhanced heme oxygenase-1 (HO-1) expression, catalase (CAT) antioxidant enzyme, and non-enzymatic antioxidant, and reduced glutathione (GSH) in LTA-induced RAW 264.7 cells. These results suggest that PTE exerts an anti-inflammatory property via attenuating NF-κB/ERK signaling pathways as well as enriching antioxidant defense mechanisms.

Platelets play a crucial role in the physiology of primary hemostasis and pathological processes such as arterial thrombosis, thus, developing a therapeutic target that prevents platelet activation can reduce arterial thrombosis. Pterostilbene (PTE) has remarkable pharmacological activities, including anticancer and neuroprotection. Few studies have reported the effects of pterostilbene on platelet activation. Thus, we examined the inhibitory mechanisms of pterostilbene in human platelets and its role in vascular thrombosis prevention in mice. At low concentrations (2–8 μM), pterostilbene strongly inhibited collagen-induced platelet aggregation. Furthermore, pterostilbene markedly diminished Lyn, Fyn, and Syk phosphorylation and hydroxyl radical formation stimulated by collagen. Moreover, PTE directly hindered integrin αIIbβ3 activation through interfering with PAC-1 binding stimulated by collagen. In addition, pterostilbene affected integrin αIIbβ3-mediated outside-in signaling, such as integrin β3, Src, and FAK phosphorylation, and reduced the number of adherent platelets and the single platelet spreading area on immobilized fibrinogen as well as thrombin-stimulated fibrin clot retraction. Furthermore, pterostilbene substantially prolonged the occlusion time of thrombotic platelet plug formation in mice. This study demonstrated that pterostilbene exhibits a strong activity against platelet activation through the inhibition of integrin αIIbβ3-mediated inside-out and outside-in signaling, suggesting that pterostilbene can serve as a therapeutic agent for thromboembolic disorders.

Myocardial infarction and cerebral ischemic stroke during the process of arterial thrombosis are prominently causes of death worldwide. Platelets are anucleated cells and play a critical factor in these diseases. Columbianadin (CBN), a coumarin derivative from plants, inhibits effective platelet activation. In this study, platelet function analysis revealed that the closure time of the platelet plug in human whole blood significantly prolonged by CBN, whereas CBN did not pointedly prolong the bleeding time in mice. BAY11-7082 (an inhibitor of I&kappa, B kinase) and MG-132 (an inhibitor of proteasome) inhibited collagen-stimulated platelet aggregation and ATP-release in human platelets, BAY11-7082 exhibited a higher potency than MG-132. Moreover, CBN markedly reduced NF-&kappa, B activation (e.g., I&kappa, B&alpha, and p65 phosphorylation) and reversed I&kappa, degradation in activated platelets. We investigated intercellular signaling events between mitogen-activated protein kinases and NF-&kappa, B, and found that BAY11-7082 abolished JNK1/2 and ERK1/2 phosphorylation. Interestingly, SP600125 (an inhibitor of JNK) but not PD98059 (an inhibitor of ERK) had no effect in NF-&kappa, B activation in activated platelets. Moreover, CBN but not BAY11-7082 significantly reduced hydroxyl radical (HO●) formation in platelets. Therefore, we propose that CBN inhibits NF-&kappa, B activation in human platelets and could present a potent clinical treatment for thromboembolic diseases.

Platelets are major players in the occurrence of cardiovascular diseases. Auraptene is the most abundant coumarin derivative from plants, and it has been demonstrated to possess a potent capacity to inhibit platelet activation. Although platelets are anucleated cells, they also express the transcription factor, nuclear factor-&kappa, B (NF-&kappa, B), that may exert non-genomic functions in platelet activation. In the current study, we further investigated the inhibitory roles of auraptene in NF-&kappa, B-mediated signal events in platelets. MG-132 (an inhibitor of proteasome) and BAY11-7082 (an inhibitor of I&kappa, B kinase, IKK), obviously inhibited platelet aggregation, however, BAY11-7082 exhibited more potent activity than MG-132 in this reaction. The existence of NF-&kappa, B (p65) in platelets was observed by confocal microscopy, and auraptene attenuated NF-&kappa, B activation such as I&kappa, B&alpha, and p65 phosphorylation and reversed I&kappa, degradation in collagen-activated platelets. To investigate cellular signaling events between PLC&gamma, 2-PKC and NF-&kappa, B, we found that BAY11-7082 abolished PLC&gamma, 2-PKC activation, nevertheless, neither U73122 nor Ro31-8220 had effect on NF-&kappa, B activation. Furthermore, both auraptene and BAY11-7082 significantly diminished HO&bull, formation in activated platelets. For in vivo study, auraptene prolonged the occlusion time of platelet plug in mice. In conclusion, we propose a novel inhibitory pathway of NF-&kappa, B-mediated PLC&gamma, 2-PKC activation by auraptene in human platelets, and further supported that auraptene possesses potent activity for thromboembolic diseases.

Lipoteichoic acid (LTA) is a key cell wall component and virulence factor of Gram-positive bacteria. LTA contributes a major role in infection and it mediates inflammatory responses in the host. Rutaecarpine, an indolopyridoquinazolinone alkaloid isolated from Evodia rutaecarpa, has shown a variety of fascinating biological properties such as anti-thrombotic, anticancer, anti-obesity and thermoregulatory, vasorelaxing activity. It has also potent effects on the cardiovascular and endocrine systems. Herein, we investigated rutaecarpine’s (Rut) anti-inflammatory effects in LTA-stimulated RAW macrophage cells. The Western blot and spectrophotometric results revealed that Rut inhibited the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and interleukin (IL)-1β in the LTA-induced macrophage cells. Successively, our mechanistic studies publicized that Rut inhibited LTA-induced phosphorylation of mitogen-activated protein kinase (MAPK) including the extracellular signal-regulated kinase (ERK), and p38, but not c-Jun NH2-terminal kinase (JNK). In addition, the respective Western blot and confocal image analyses exhibited that Rut reserved nuclear transcription factor kappa-B (NF-κB) by hindering inhibitor of nuclear factor κB-α (IκBα) and NF-κB p65 phosphorylation and p65 nuclear translocation. These results indicate that Rut exhibits its anti-inflammatory effects mainly through attenuating NF-κB and ERK/p38 signaling pathways. Overall, this result suggests that Rut could be a potential therapeutic agent for the treatment of Gram-positive bacteria induced inflammatory diseases.

Auraptene is the most abundant coumarin derivative from plants. The pharmacological value of this compound has been well demonstrated, especially in the prevention of cancer and neurodegenerative diseases. Platelet activation is a major factor contributing to arterial thrombosis. Thus, this study evaluated the influence of auraptene in platelet aggregation and thrombotic formation. Auraptene inhibited platelet aggregation in human platelets stimulated with collagen only. However, auraptene was not effective in inhibiting platelet aggregation stimulated with thrombin, arachidonic acid, and U46619. Auraptene also repressed ATP release, [Ca2+]i mobilization, and P-selectin expression. Moreover, it markedly blocked PAC-1 binding to integrin &alpha, IIb&beta, 3. However, it had no influence on properties related to integrin &alpha, 3-mediated outside-in signaling, such as the adhesion number, spreading area of platelets, and fibrin clot retraction. Auraptene inhibited the phosphorylation of Lyn-Fyn-Syk, phospholipase C&gamma, 2 (PLC&gamma, 2), protein kinase C (PKC), Akt, and mitogen-activated protein kinases (MAPKs, extracellular-signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK1/2), but not p38 MAPK). Neither SQ22536, an adenylate cyclase inhibitor, nor ODQ, a guanylate cyclase inhibitor, reversed the auraptene-mediated inhibition of platelet aggregation. Auraptene reduced mortality caused by adenosine diphosphate (ADP)-induced pulmonary thromboembolism. In conclusion, this study provides definite evidence that auraptene signifies a potential therapeutic agent for preventing thromboembolic disorders.

Esculetin, a bioactive 6,7-dihydroxy derivative of coumarin, possesses pharmacological activities against obesity, diabetes, renal failure, and cardiovascular disorders (CVDs). Platelet activation plays a major role in CVDs. Thus, disrupting platelet activation represents an attractive therapeutic target. We examined the effect of esculetin in human platelet activation and experimental mouse models. At 10&ndash, 80 &mu, M, esculetin inhibited collagen- and arachidonic acid-induced platelet aggregation in washed human platelets. However, it had no effects on other agonists such as thrombin and U46619. Esculetin inhibited adenosine triphosphate release, P-selectin expression, hydroxyl radical (OH&middot, ) formation, Akt activation, and phospholipase C (PLC)&gamma, 2/protein kinase C (PKC) phosphorylation, but did not diminish mitogen-activated protein kinase phosphorylation in collagen-activated human platelets. Platelet function analysis indicated that esculetin substantially prolonged the closure time of whole blood. In experimental mice, esculetin significantly increased the occlusion time in thrombotic platelet plug formation and reduced mortality associated with acute pulmonary thromboembolism. However, it did not prolong the bleeding time. This study demonstrates that esculetin inhibits human platelet activation via hindering the PLC&gamma, 2&ndash, PKC cascade, hydroxyl radical formation, Akt activation, and ultimately suppressing platelet activation. Therefore, esculetin may act as an essential therapeutic agent for preventing thromboembolic diseases.

Myocardial infarction and cerebral ischemic stroke are prominent causes of death worldwide. Platelets play major roles in these diseases, although they are anucleated cells, but also express the NF-κB. Pterostilbene (PTE) possesses some intriguing pharmacological properties, including the capacity to inhibit platelet activation. We investigated the inhibitory role of PTE in NF-κB-mediated signal events and compared the relative potency with that of classical NF-κB inhibitors. PTE and IκB kinase (IKK) inhibitor, BAY11-7082, and proteasome inhibitor, Ro106-9920, inhibited platelet aggregation, the activity of BAY11-7082 and PTE were similar, but Ro106-9920 was weak in this reaction. PTE and BAY11-7082 diminished NF-κB signaling molecules, including IKK, IκBα, and p65 phosphorylation, and reversed IκBα degradation. However, Ro106-9920 was only effective in diminishing p65 phosphorylation and reversing IκBα degradation. In investigating the role of Akt and NF-κB in cell signaling events, MK-2206 (an inhibitor of Akt) markedly abolished IKK and p65 phosphorylation, BAY11-7082 also reduced Akt phosphorylation. PTE exhibited more potent activity in vivo than did BAY11-7082 in acute pulmonary thromboembolism. In conclusion, we identified a distinctive activation pathway of NF-κB and Akt involved in PTE-mediated antiplatelet aggregation, and PTE demonstrated powerful activity as a prophylactic and as clinical therapy for cardiovascular diseases.

Platelets play a major role in hemostatic events and are associated with various pathological events, such as arterial thrombosis and atherosclerosis. Iridium (Ir) compounds are potential alternatives to platinum compounds, since they exert promising anticancer effects without cellular toxicity. Our recent studies found that Ir compounds show potent antiplatelet properties. In this study, we evaluated the in vitro antiplatelet, in vivo antithrombotic and structure&ndash, activity relationship (SAR) of newly synthesized Ir complexes, Ir-1, Ir-2 and Ir-4, in agonists-induced human platelets. Among the tested compounds, Ir-1 was active in inhibiting platelet aggregation induced by collagen, however, Ir-2 and Ir-4 had no effects even at their maximum concentrations of 50 &mu, M against collagen and 500 &mu, M against U46619-induced aggregation. Similarly, Ir-1 was potently inhibiting of adenosine triphosphate (ATP) release, calcium mobilization ([Ca2+]i) and P-selectin expression induced by collagen-induced without cytotoxicity. Likewise, Ir-1 expressively suppressed collagen-induced Akt, PKC, p38MAPKs and JNK phosphorylation. Interestingly, Ir-2 and Ir-4 had no effect on platelet function analyzer (PFA-100) collagen-adenosine diphosphate (C-ADP) and collagen-epinephrine (C-EPI) induced closure times in mice, but Ir-1 caused a significant increase when using C-ADP stimulation. Other in vivo studies revealed that Ir-1 significantly prolonged the platelet plug formation, increased tail bleeding times and reduced the mortality of adenosine diphosphate (ADP)-induced acute pulmonary thromboembolism in mice. Ir-1 has no substitution on its phenyl group, a water molecule (like cisplatin) can replace its chloride ion and, hence, the rate of hydrolysis might be tuned by the substituent on the ligand system. These features might have played a role for the observed effects of Ir-1. These results indicate that Ir-1 may be a lead compound to design new antiplatelet drugs for the treatment of thromboembolic diseases.

Morin hydrate, a bioactive flavonoid, has been proven to prevent inflammation and apoptosis of cells. Flavonoids can reduce the risk of cardiovascular diseases, in which platelet activation plays a major role. This study investigated the effect of morin hydrate on platelet activation in vitro and in vivo. Morin hydrate markedly inhibited platelet aggregation stimulated by collagen in human platelets but not that stimulated by other agonists. In collagen-activated platelets, morin hydrate inhibited adenosine triphosphate (ATP) release, intracellular Ca2+ mobilization, P-selectin expression, and phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), and Akt. In mitogen-activated protein kinase (MAPK) activation, morin hydrate evidently diminished ERK2 or JNK1 activation, except for p38 MAPK. Additionally, morin hydrate markedly reduced the OH· signals in platelet suspensions but not in the cell-free system (Fenton reaction solution). Moreover, morin hydrate substantially increased the occlusion time of thrombotic platelet plug formation but had no effect on bleeding time in mice. In conclusion, morin hydrate crucially inhibits platelet activation through inhibition of the PLCγ2–PKC cascade and subsequent suppression of Akt and MAPK activation, thereby ultimately inhibiting platelet aggregation. Therefore, this paper suggests that morin hydrate constitutes a novel and potential natural therapeutic product for preventing or treating thromboembolic disorders.

In oncotherapy, ruthenium (Ru) complexes are reflected as potential alternatives for platinum compounds and have been proved as encouraging anticancer drugs with high efficacy and low side effects. Cardiovascular diseases (CVDs) are mutually considered as the number one killer globally, and thrombosis is liable for the majority of CVD-related deaths. Platelets, an anuclear and small circulating blood cell, play key roles in hemostasis by inhibiting unnecessary blood loss of vascular damage by making blood clot. Platelet activation also plays a role in cancer metastasis and progression. Nevertheless, abnormal activation of platelets results in thrombosis under pathological settings such as the rupture of atherosclerotic plaques. Thrombosis diminishes the blood supply to the heart and brain resulting in heart attacks and strokes, respectively. While currently used anti-platelet drugs such as aspirin and clopidogrel demonstrate efficacy in many patients, they exert undesirable side effects. Therefore, the development of effective therapeutic strategies for the prevention and treatment of thrombotic diseases is a demanding priority. Recently, precious metal drugs have conquered the subject of metal-based drugs, and several investigators have motivated their attention on the synthesis of various ruthenium (Ru) complexes due to their prospective therapeutic values. Similarly, our recent studies established that novel ruthenium-based compounds suppressed platelet aggregation via inhibiting several signaling cascades. Our study also described the structure antiplatelet-activity relationship (SAR) of three newly synthesized ruthenium-based compounds. This review summarizes the antiplatelet activity of newly synthesized ruthenium-based compounds with their potential molecular mechanisms.

Platelet activation plays a major role in cardio and cerebrovascular diseases, and cancer progression. Disruption of platelet activation represents an attractive therapeutic target for reducing the bidirectional cross talk between platelets and tumor cells. Platinum (Pt) compounds have been used for treating cancer. Hence, replacing Pt with iridium (Ir) is considered a potential alternative. We recently developed an Ir(III)-derived complex, [Ir(Cp*)1-(2-pyridyl)-3-(2-hydroxyphenyl)imidazo[1,5-a]pyridine Cl]BF4 (Ir-11), which exhibited strong antiplatelet activity; hence, we assessed the therapeutic potential of Ir-11 against arterial thrombosis. In collagen-activated platelets, Ir-11 inhibited platelet aggregation, adenosine triphosphate (ATP) release, intracellular Ca2+ mobilization, P-selectin expression, and OH· formation, as well as the phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), and Akt. Neither the adenylate cyclase inhibitor nor the guanylate cyclase inhibitor reversed the Ir-11-mediated antiplatelet effects. In experimental mice, Ir-11 prolonged the bleeding time and reduced mortality associated with acute pulmonary thromboembolism. Ir-11 plays a crucial role by inhibiting platelet activation through the inhibition of the PLCγ2–PKC cascade, and the subsequent suppression of Akt and MAPK activation, ultimately inhibiting platelet aggregation. Therefore, Ir-11 can be considered a new therapeutic agent against either arterial thrombosis or the bidirectional cross talk between platelets and tumor cells.