Role of heterotrimeric G proteins in platelet activation and clot formation in platelets treated with integrin αIIbβ3 inhibitor

Curdione inhibits thrombin-induced platelet aggregation via regulating the AMP-activated protein kinase-vinculin/talin-integrin αIIbβ3 sign pathway

BACKGROUND

Curdione, a sesquiterpene compound isolated from the essential oil of Curcuma aromatica Salisb. inhibits platelet aggregation, suggesting its significant anticoagulant and antithrombotic effects. However, the mechanisms have not been fully elucidated.

HYPOTHESIS

We hypothesized that curdione inhibits thrombin-induced platelet aggregation via regulating the AMP-activated protein kinase-vinculin/talin-integrin αIIbβ3 signaling pathway.

STUDY DESIGN

We performed in vitro assays to evaluate the effect of curdione on thrombin-induced expression levels of the AMPK signaling molecule and integrin αIIbβ3 signaling pathway components.

METHODS

Platelet proteins were extracted from washed human platelets, and the effects of curdione on thrombin-induced platelet aggregation were evaluated. The expression levels of the AMPK signaling molecule and integrin αIIbβ3 signaling pathway-related proteins were examined using western blot and RT-PCR. The binding of vinculin and talin were studied using immunoprecipitation, double immunofluorescence staining and microscale thermophoresis.

RESULTS

Platelet aggregation analysis showed that 0.02 U/ml thrombin significantly induces platelet aggregation. Western blot and RT-PCR analysis revealed that AMPK inhibits the vinculin/talin-mediated integrin αIIbβ3 signaling pathway, and curdione downregulates the thrombin-induced expression of phosphorylated AMPK (P-AMPK) and P-integrin at both the protein and mRNA levels and downregulates vinculin and talin at the protein level. Furthermore, microscale thermophoresis experiments showed that curdione inhibits the binding of vinculin and talin. The results from the immunoprecipitation and double immunofluorescence staining were consistent with the results of the microscale thermophoresis experiments.

CONCLUSION

Curdione inhibits thrombin-induced platelet aggregation via regulating the AMP-activated protein kinase-vinculin/talin-integrin αIIbβ3 signaling pathway, which suggests its therapeutic potential in ethnomedicinal applications as an anti-platelet and anti-thrombotic compound to prevent thrombotic diseases.

The association between hematological parameters and metabolic syndrome in Iranian men: A single center large-scale study

AIMS

Some studies have demonstrated that metabolic syndrome is associated with hematological parameters. The present study explores the relationship between hematological parameters and numbers of metabolic syndrome conditions in Iranian men.

METHODS

This cross-sectional study included 11,114 participants who were professional drivers of commercial motor vehicles, and were enrolled in the Iranian Health Surveys between 2014 and 2016. Diagnosis of metabolic syndrome was made according to International Diabetes Federation criteria. Clinical data, including anthropometric measurements and serum parameters, were collected. Odds ratios for hematological parameters and metabolic syndrome were calculated using binary logistic regression models.

RESULTS

We found that hemoglobin; platelet, and white blood cell counts increased with increasing numbers of metabolic syndrome components (p<0.05 for all). The odds ratio of metabolic syndrome significantly increased across successive quartiles of platelet (1.00, 1.25, 1.29, and 1.51) and white blood cell counts (1.00, 1.51, 1.79, and 2.11) with the lowest quartile as the referent group. Similar associations for hemoglobin and hematocrit in the top quartile were also observed. We did not observe any significant difference in the mean of neutrophil count, mean platelet volume (MPV), red cell distribution width, or platelet distribution width among participants with or without metabolic syndrome.

CONCLUSIONS

Our findings indicate that high levels of major hematological parameters such as hemoglobin, hematocrit, as well as platelet and white blood cell counts could be novel indicators for the development of metabolic syndrome.

Ketoacidosis alone does not predispose to mucormycosis by Lichtheimia in a murine pulmonary infection model

Mucormycosis is a rare fungal infection; however, the number of cases increased during the last decades. The main risk factors are immunosuppression and uncontrolled diabetes mellitus. Although Lichtheimia species represent a common cause of mucormycosis in Europe, virulence and pathogenesis of this genus has not been investigated in detail yet. Using murine pulmonary infection models, we found that immunosuppression is essential for establishment of infection. The disease was characterized by necrosis, angioinvasion, thrombosis, and the lethal course of infection was associated with systemic activation of platelets. Furthermore, dissemination to internal organs was frequently observed. While the virulence potential of individual L. corymbifera and L. ramosa isolates differed, pathogenicity of both species was comparable. Although ketoacidosis promoted Rhizopus infection in mice, it did not predispose mice to infection with Lichtheimia in the absence of additional immunosuppression. This might partially explain the dominance of Rhizopus as cause of mucormycosis in countries with high prevalence of ketoacidotic patients.