Platelet SHARPIN regulates platelet adhesion and inflammatory responses through associations with αIIbβ3 and LUBAC

The role of platelets in central hubs of inflammation: A literature review

Platelets are increasingly recognized for their multifaceted roles in inflammation beyond their traditional involvement in haemostasis. This review consolidates knowledge on platelets as critical players in inflammatory responses. This study did an extensive search of electronic databases and identified studies on platelets in inflammation, focusing on molecular mechanisms, cell interactions, and clinical implications, emphasizing recent publications. Platelets contribute to inflammation via surface receptors, release of mediators, and participation in neutrophil extracellular trap formation. They are implicated in diseases like atherosclerosis, rheumatoid arthritis, and sepsis, highlighting their interaction with immune cells as pivotal in the onset and resolution of inflammation. Platelets are central to regulating inflammation, offering new therapeutic targets for inflammatory diseases. Future research should explore specific molecular pathways of platelets in inflammation for therapeutic intervention.

Elevated serum fibrinogen levels in Chinese patients with minor recurrent aphthous stomatitis: An observational study

Fibrinogen is a protein that reflects systemic inflammation and regulates the immune response to disease. However, there is a scarcity of data on fibrinogen in recurrent aphthous stomatitis (RAS). We aimed to test the hypothesis that fibrinogen is involved in the aetiology of RAS. Between November 2016 and November 2018, we included 109 minor RAS patients and 29 age- and sex-matched controls in a single-center, observational study. Their clinical history and ulcer manifestations led to the diagnosis of minor RAS. The ulcer severity score (USS) was used to assess disease severity, and fibrinogen was also collected. We conducted three analyses: Analysis 1 (comparison of fibrinogen levels between patients and controls), Analysis 2 (comparison of fibrinogen levels between high and low USS patients) and Analysis 3 (comparison of fibrinogen levels between before and after anti-inflammatory treatment in patients). The fibrinogen levels in the 109 minor RAS patients were statistically higher than in the 29 controls (mean [SD], 2.6 [0.5] vs. 2.3 [0.3]; Student's t-test, p < 0.001). However, there were no significant differences in fibrinogen levels among the 43 patients with high USS and the 39 patients with low USS (mean [SD], 2.7 [0.5] vs. 2.6 [0.4]; Student's t-test, p = 0.278). Furthermore, fibrinogen levels were significantly higher before anti-inflammatory treatment in comparison to those after anti-inflammatory treatment in the 35 paired patients (mean [SD], 2.6 [0.4] vs. 2.5 [0.4]; Student's t-test, p = 0.026). Interestingly, fibrinogen levels were significantly higher in the 35 paired patients after anti-inflammatory treatment compared to the 29 control subjects (mean [SD], 2.5 [0.4] vs. 2.3 [0.3]; Student's t-test, p = 0.026]. Fibrinogen may play a role in the aetiology of RAS and may be a drug target for RAS treatment. Clinicians should be alert that high serum fibrinogen levels might be associated with the risk of RAS.

Structure, signal transduction, activation, and inhibition of integrin αIIbβ3

Integrins are heterodimeric receptors comprising α and β subunits. They are expressed on the cell surface and play key roles in cell adhesion, migration, and growth. Several types of integrins are expressed on the platelets, including αvβ3, αIIbβ3, α2β1, α5β1, and α6β1. Among these, physically αIIbβ3 is exclusively expressed on the platelet surface and their precursor cells, megakaryocytes. αIIbβ3 adopts at least three conformations: i) bent-closed, ii) extended-closed, and iii) extended-open. The transition from conformation i) to iii) occurs when αIIbβ3 is activated by stimulants. Conformation iii) possesses a high ligand affinity, which triggers integrin clustering and platelet aggregation. Platelets are indispensable for maintaining vascular system integrity and preventing bleeding. However, excessive platelet activation can result in myocardial infarction (MI) and stroke. Therefore, finding a novel strategy to stop bleeding without accelerating the risk of thrombosis is important. Regulation of αIIbβ3 activation is vital for this strategy. There are a large number of molecules that facilitate or inhibit αIIbβ3 activation. The interference of these molecules can accurately control the balance between hemostasis and thrombosis. This review describes the structure and signal transduction of αIIbβ3, summarizes the molecules that directly or indirectly affect integrin αIIbβ3 activation, and discusses some novel antiαIIbβ3 drugs. This will advance our understanding of the activation of αIIbβ3 and its essential role in platelet function and tumor development.

RNA-Binding Proteins: Emerging Therapeutics for Vascular Dysfunction

Vascular diseases account for a significant number of deaths worldwide, with cardiovascular diseases remaining the leading cause of mortality. This ongoing, ever-increasing burden has made the need for an effective treatment strategy a global priority. Recent advances in regenerative medicine, largely the derivation and use of induced pluripotent stem cell (iPSC) technologies as disease models, have provided powerful tools to study the different cell types that comprise the vascular system, allowing for a greater understanding of the molecular mechanisms behind vascular health. iPSC disease models consequently offer an exciting strategy to deepen our understanding of disease as well as develop new therapeutic avenues with clinical translation. Both transcriptional and post-transcriptional mechanisms are widely accepted to have fundamental roles in orchestrating responses to vascular damage. Recently, iPSC technologies have increased our understanding of RNA-binding proteins (RBPs) in controlling gene expression and cellular functions, providing an insight into the onset and progression of vascular dysfunction. Revelations of such roles within vascular disease states have therefore allowed for a greater clarification of disease mechanisms, aiding the development of novel therapeutic interventions. Here, we discuss newly discovered roles of RBPs within the cardio-vasculature aided by iPSC technologies, as well as examine their therapeutic potential, with a particular focus on the Quaking family of isoforms.