Critical role of peroxisome proliferator-activated receptor α in promoting platelet hyperreactivity and thrombosis under hyperlipidemia.

Platelet hyperreactivity and increased atherothrombotic risk are specifically associated with dyslipidemia. Peroxisome proliferator-activated receptor alpha (PPARα) is an important regulator of lipid metabolism. It has been suggested to affect both thrombosis and hemostasis, yet the underlying mechanisms are not well understood. In this study, the role and mechanism of PPARα in platelet activation and thrombosis related to dyslipidemia were examined. Employing mice with deletion of PPARα (Pparα-/-), we demonstrated that PPARa is required for platelet activation and thrombus formation. The effect of PPARα is critically dependent on platelet dense granule secretion, and is contributed by p38MAPK/Akt, fatty acid b-oxidation, and NAD(P)H oxidase pathways. Importantly, PPARα and the associated pathways mediated a prothrombotic state induced by a high-fat diet and platelet hyperactivity provoked by oxidized low density lipoproteins. Platelet reactivity was positively correlated with the levels of expression of PPARα, as revealed by data from wild-type, chimeric (Pparα+/-), and Pparα-/- mice. This positive correlation was recapitulated in platelets from hyperlipidemic patients. In a lipid-treated megakaryocytic cell line, the lipid-induced reactive oxygen species-NF-kB pathway was revealed to upregulate platelet PPARα in hyperlipidemia. These data suggest that platelet PPARα critically mediates platelet activation and contributes to the prothrombotic status under hyperlipidemia.

Migfilin supports hemostasis and thrombosis through regulating platelet αIIbß3 outside-in signaling.

Elucidating the regulation mechanism of integrin αIIbß3 is key to understand platelet biology and thrombotic diseases. Previous in vitro studies have implicated a role of migfilin in the support of platelet αIIbß3 activation, however, contribution of migfilin to thrombosis and hemostasis in vivo and a detailed mechanism of migfilin in platelets are not known. In this study, with migfilin deletion (migfilin-/-) mice, we report that migfilin is a pivotal positive regulator of hemostasis and thrombosis. Migfilin-/- mice showed a nearly doubled tail-bleeding time and a prolonged occlusion time in Fecl3-induced mesenteric arteriolar thrombosis. Migfilin deficiency impedes platelet thrombi formation on collagen surface and impairs platelet aggregation and dense-granule secretion. Supported by characteristic functional readings and phosphorylation status of distinctive signaling molecules in the bidirectional signaling processes of αIIbß3, the functional defects of migfilin-/- platelets appear to be mechanistically associated with a compromised outside-in signaling, rather than inside-out signaling. A synthesized cell-permeable migfilin peptide harboring filamin A binding sequence rescued the defective function and phosphorylation of signaling molecules of migfilin-/- platelets. Finally, migfilin does not influence the binding of filamin A and ß3 subunit of αIIbß3 in resting platelets, but hampers the re-association of filamin A and ß3 during the conduct of outside-in signaling, suggesting that migfilin functions through regulating the interaction dynamics of αIIbß3 and filamin A in platelets. Our study enhances the current understanding of platelet integrin αIIbß3-mediated outside-in signaling and proves that migfilin is an important regulator for platelet activation, hemostasis and thrombosis.

Self-Assessed Educational Needs of Chinese Pediatric Clinicians Regarding Pediatric Palliative Care: A Cross-Sectional Investigation.

BACKGROUND: An important first step in enhancing professional palliative care training is to investigate the educational needs of pediatric clinicians in this field. The aims of this research were to analyze the extent of end-of-life care experience of Chinese pediatric clinicians and identify the differing educational needs of physicians and nurses as well as associated impact factors. METHODS: A cross-sectional descriptive survey via a structural questionnaire was used in this research. RESULTS: In total, 187 clinicians, comprising 52 physicians and 135 nurses, participated in this study. The topics "pain management", "symptom management", and "discussing the prognosis with family members" were the most expressed educational needs among both physicians and nurses. Compared to nurses, physicians placed greater emphasis on the importance of "communication" and "pain and symptom management" (p < 0.05). Clinicians with more extensive end-of-life care experience more strongly felt the importance of learning about pain management and communication regarding end-of-life care (p < 0.05). CONCLUSIONS: Research showed that the education currently provided to pediatric clinicians does not meet their distinctive needs. Future palliative care education must be a continuing multi-level, interdisciplinary program and different education should be provided to physicians and nurses based on their respective needs.

Inflammasome-Independent Mechanism of NLRP3 Is Critical for Platelet GPIb-IX Function and Thrombosis.

INTRODUCTION: Platelets link thrombosis and inflammation, but how platelets handle the endogenous intraplatelet inflammatory machinery is less well understood. NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) is the central component of the interleukin (IL)-1-producing inflammasome. Elucidating the cell type-specific mechanism of NLRP3 in platelets may improve our understanding of thrombotic diseases. METHODS: Ferric chloride-induced mesenteric arteriole thrombosis models, tail bleeding models, and microfluidic whole-blood perfusion were used to study thrombosis and hemostasis. Additionally, we utilized aggregometry, flow cytometry, immunoprecipitation, and western blotting to investigate glycoprotein (GP)Ib-IX-mediated platelet function and signaling. RESULTS: NLRP3-/- mice exhibited severely impaired thrombosis and hemostasis, whereas apoptosis-associated speck-like protein containing a CARD (ASC)-/-, caspase-1-/-, and Nlrp3 A350V/+ CrePF4 mice did not exhibit such changes. NLRP3-/- platelets exhibited reduced adhesion to injured vessel walls and collagen and impaired von Willebrand factor (vWF)-dependent translocation and rolling behavior. NLRP3 deficiency decreased botrocetin-induced platelet aggregation and the phosphorylation of key signaling molecules in the GPIb-IX pathway. Mechanistically, decreased cAMP/PKA activity led to reduced phosphorylation of NLRP3, thereby enabling the interaction between NLRP3 and filamin A. This interaction accelerated the dissociation of filamin A from GPIbα, which allowed a 14-3-3ζ-dependent increase in GPIb-IX affinity to vWF. Finally, platelet NLRP3 was found to largely regulate thrombotic disease models, such as models of stroke and deep vein thrombosis. CONCLUSION: NLRP3 promoted the function of the major platelet adhesion receptor GPIb-IX without involving NLRP3 inflammasome assembly or IL-1ß production.

Phylogeographic analysis elucidates the influence of the ice ages on the disjunct distribution of relict dragonflies in Asia.

Unusual biogeographic patterns of closely related groups reflect events in the past, and molecular analyses can help to elucidate these events. While ample research on the origin of disjunct distributions of different organism groups in the Western Paleartic has been conducted, such studies are rare for Eastern Palearctic organisms. In this paper we present a phylogeographic analysis of the disjunct distribution pattern of the extant species of the strongly cool-adapted Epiophlebia dragonflies from Asia. We investigated sequences of the usually more conserved 18 S rDNA and 28 S rDNA genes and the more variable sequences of ITS1, ITS2 and CO2 of all three currently recognised Epiophlebia species and of a sample of other odonatan species. In all genes investigated the degrees of similarity between species of Epiophlebia are very high and resemble those otherwise found between different populations of the same species in Odonata. This indicates that substantial gene transfer between these populations occurred in the comparatively recent past. Our analyses imply a wide distribution of the ancestor of extant Epiophlebia in Southeast Asia during the last ice age, when suitable habitats were more common. During the following warming phase, its range contracted, resulting in the current disjunct distribution. Given the strong sensitivity of these species to climatic parameters, the current trend to increasing global temperatures will further reduce acceptable habitats and seriously threaten the existences of these last representatives of an ancient group of Odonata.