The neutrophil serine protease PR3 induces shape change of platelets via the Rho/Rho kinase and Ca(2+) signaling pathways

Inflammatory Proteins HMGA2 and PRTN3 as Drivers of Vulvar Squamous Cell Carcinoma Progression

Current knowledge on the biology of squamous cell vulvar carcinoma (VSCC) is limited. We aimed to identify protein markers of VSCC tumors that would permit to stratify patients by progression risk. Early-stage tumors from patients who progressed (progVSCC) and from those who were disease-free (d-fVSCC) during follow-up, along with normal vulvar tissues were examined by mass spectrometry-based proteomics. Differentially expressed proteins (DEPs) were then verified in solid tissues and blood samples of patients with VSCC tumors and vulvar premalignant lesions. In progVSCC vs. d-fVSCC tumors, the immune response was the most over-represented Gene Ontology category for the identified DEPs. Pathway profiling suggested bacterial infections to be linked to aggressive VSCC phenotypes. High Mobility Group AT-Hook 2 (HMGA2) and Proteinase 3 (PRTN3) were revealed as proteins predicting VSCC progression. HMGA2 and PRTN3 abundances are associated with an aggressive phenotype, and hold promise as markers for VSCC patient stratification. It appears that vulvovaginal microflora disturbances trigger an inflammatory response contributing to cancer progression, suggesting that bacterial rather than viral infection status should be considered in the development of targeted therapies in VSCC.

Proteinase 3 expression on the neutrophils of patients with paroxysmal nocturnal hemoglobinuria

Proteinase 3 (PR3) is released from neutrophils and regulates platelet activity, which is associated with cluster of differentiation (CD)177 antigen (NB1), a glycosylphosphatidylinositol-linked protein. In the present study, the effect of PR3 on thrombosis in paroxysmal nocturnal hemoglobinuria (PNH) and PNH-aplastic anemia (AA) syndrome was explored. The expression of PR3 and NB1 on CD59^- neutrophils was detected by flow cytometry, immunofluorescence (IF), reverse transcription-quantitative polymerase chain reaction analysis and western blotting. Serum levels of PR3, proteinase-activated receptor 1 (PAR1) and D-Dimer were measured using ELISAs. The expression of PR3 and NB1 on the plasma membrane of CD59^- neutrophils in patients with PNH/PNH-AA was significantly lower compared with their expression on CD59⁺ neutrophils in patients and controls (P=0.001). However, no correlation between PR3 and NB1 expression was identified. IF staining further demonstrated partially positive PR3 expression on CD59^- neutrophils. The serum level of PR3 in patients was identified to be significantly decreased compared with healthy controls (P<0.0001), and significantly negatively correlated with PAR1 (r=-0.456; P=0.043) and D-Dimer (r=-0.503; P=0.028) levels. The mRNA and protein levels of PR3 on PNH clones did not change significantly compared with the control group. In conclusion, PR3 expression on the plasma membrane of neutrophils and in the serum of patients with PNH/PNH-AA decreased, which may result in increased PAR1 expression and increased clotting. The present study provides the basis for further study on platelets in PNH.

The use of flow cytometry to examine calcium signalling by TRPV1 in mixed cell populations

Flow cytometric analysis of calcium mobilisation has been in use for many years in the study of specific receptor engagement or isolated cell:cell communication. However, calcium mobilisation/signaling is key to many cell functions including apoptosis, mobility and immune responses. Here we combine multiplex surface staining of whole spleen with Indo-1 AM to visualise calcium mobilisation and examine calcium signaling in a mixed immune cell culture over time. We demonstrate responses to a TRPV1 agonist in distinct cell subtypes without the need for cell separation. Multi parameter staining alongside Indo-1 AM to demonstrate calcium mobilization allows the study of real time calcium signaling in a complex environment.

Proteolytic receptor cleavage in the pathogenesis of blood rheology and co-morbidities in metabolic syndrome. Early forms of autodigestion

Abnormal blood rheological properties seldom occur in isolation and instead are accompanied by other complications, often designated as co-morbidities. In the metabolic syndrome with complications like hypertension, diabetes and lack of normal microvascular blood flow, the underlying molecular mechanisms that simultaneously lead to elevated blood pressure and diabetes as well as abnormal microvascular rheology and other cell dysfunctions have remained largely unknown. In this review, we propose a new hypothesis for the origin of abnormal cell functions as well as multiple co-morbidities. Utilizing experimental models for the metabolic disease with diverse co-morbidities we summarize evidence for the presence of an uncontrolled extracellular proteolytic activity that causes ectodomain receptor cleavage and loss of their associated cell function. We summarize evidence for unchecked degrading proteinase activity, e.g. due to matrix metalloproteases, in patients with hypertension, Type II diabetes and obesity, in addition to evidence for receptor cleavage in the form of receptor fragments and decreased extracellular membrane expression levels. The evidence suggest that a shift in blood rheological properties and other co-morbidities may in fact be derived from a common mechanism that is due to uncontrolled proteolytic activity, i.e. an early form of autodigestion. Identification of the particular proteases involved and the mechanisms of their activation may open the door to treatment that simultaneously targets multiple co-morbidities in the metabolic syndrome.

Proteinase 3 Induces Neuronal Cell Death Through Microglial Activation

Proteinase 3 (PR3) is released from neutrophil granules and is involved in the inflammatory process. PR3 is implicated in antimicrobial defense and cell death, but the exact role of PR3 in the brain is less defined. Microglia is the major immune effector cells in the CNS and is activated by brain injury. In the present study, the effect of PR3 on glial activation was investigated. Microglial activation was assessed by the intracellular level of reactive oxygen species and expression of inflammatory cytokines. The conditioned media from activated microglia by PR3 was used for measuring the neurotoxic effects of PR3-stimulated microglia. The effects of PR3 in vivo were measured by microinjecting PR3 into the rat brain. Herein we show that PR3 increased the inflammatory responses including the intracellular ROS and pro-inflammatory cytokine production in rat primary microglia. Conditioned media from PR3-treated microglia induced neuronal cell death in a concentration dependent manner. Furthermore, microinjected PR3 into the striatum of the rat brain induced microglial activation and neuronal cell death. Interestingly treatment with anti-PR3 monoclonal antibody and protease inhibitors ameliorated microglial activation induced by PR3 in primary microglia and striatum, which also prevented neuronal cell death in both conditions. The data presented here suggest that PR3 is a direct modulator of microglial activation and causes neuronal death through the augmentation of inflammatory responses. We suggest that PR3 could be a new modulator of neuroinflammation, and blocking PR3 would be a promising novel therapeutic target for neuroinflammatory disease such as stroke and Alzheimer's disease.