Biology subjects

Chandrabalan, A.

Publications and source records attributed to Chandrabalan, A..

3 recordsLinked to original sources

bioRxiv2022

Autocrine Proteinase Activated Receptor (PAR) mediated signaling in prostate cancer cells.

Proteinase activated receptors (PARs) are G protein-coupled receptors (GPCRs) activated by limited N-terminal proteolysis. A variety of proteolytic enzymes derived from the coagulation cascade and inflammatory milieu activate PARs, however specific activators in different physiological and pathophysiological contexts remain poorly defined. PARs are highly expressed in many cancer cells and regulate various aspects of tumor growth and metastasis. Endogenous proteinases that regulate PARs in the setting of various tumors however remains unresolved. Prostate cancer (PCa) remains a major cause of mortality in men despite advances in early detection and clinical intervention. PAR expression has been reported in PCa, however, their role here remains poorly defined. In androgen independent PC3 cells, we find functional expression of PAR1 and PAR2 but not PAR4. Using genetically encoded PAR cleavage biosensors, we find that PCa cells secrete proteolytic enzymes that cleave PARs and trigger autocrine signaling. Deletion of PAR1 and PAR2 using CRISPR/Cas9 combined with microarray analysis revealed genes that are differentially regulated by this autocrine signalling mechanism. Interestingly, several genes that are known PCa prognostic factors or biomarker were differentially expressed in PAR1-KO and PAR2-KO PC3 cells. We also examined PAR1 and PAR2 regulation of PCa cell proliferation and migration using PAR1 and PAR2-KO PC3 cells, as well as PAR1 and PAR2 specific agonists and antagonists. We find that PAR1 and PAR2 have opposite effects on PC3 cell proliferation and migration. In summary, we have identified an autocrine signaling mechanism through PARs as a regulator of PCa cell function.

cancer biology↗

bioRxiv2021

S. aureus-serine protease-like protein B (SplB) activates PAR2 and induces endothelial barrier dysfunction

Withdrawal StatementThe authors have withdrawn their manuscript owing to the following reason: Unfortunately, the preparation of the recombinant serine protease-like protein B (SplB) used in this study was found to contain impurities, so that the effects presented cannot be unambiguously attributed to the protease SplB. We therefore retract the manuscript from bioRxiv. We apologize for any inconvenience this may have caused. Therefore, the authors do not wish this work to be cited as reference for the project. We want to clarify that the issue was identified in the preparation of the SplB protein and does not reflect on the contributions of individual authors. If you have any questions, please contact the corresponding author.

immunology↗

bioRxiv2020

Identification of Proteinase Activated Receptor (PAR) cleaving enzymes in human osteoarthritis knee joint synovial fluids.

ObjectiveOsteoarthritis (OA) is the most prevalent joint disorder with incidence increasing worldwide. Mechanistic insights into OA pathophysiology are still evolving and there are currently no disease-modifying OA drugs available. It is well established that an increase in proteolytic enzyme activity is linked to progressive degradation of the cartilage in OA. Proteolytic enzymes can also trigger inflammation through activation of a family of G-protein coupled receptors (GPCRs) called the Proteinase Activated Receptors (PARs). Here we sought to characterize the PAR activating enzyme repertoire in human OA knee joint fluids. MethodsHuman knee joint synovial fluids derived from twenty-five OA patients and four healthy donors were screened for PAR cleavage activity using novel genetically encoded human PAR biosensor expressing cells. The class or type of enzymes cleaving the PARs was further characterized using enzyme-selective inhibitors and enzyme-specific fluorogenic substrates. ResultsActivity of PAR1, PAR2 and PAR4 activating enzymes were identified at substantially different levels in OA patients relative to healthy knee joint synovial fluids. Using enzyme class or type selective inhibitors and fluorogenic substrates we found that serine proteinases, including thrombin-like enzymes, trypsin-like enzymes, and matrix metalloproteinases are the major PAR activating enzymes present in the OA knee synovial fluids. ConclusionsMultiple enzymes activating PAR1, PAR2 and PAR4 are present in OA joint fluids. PAR signalling can trigger pro-inflammatory responses and targeting PARs has been proposed as a therapeutic approach in OA. Knowledge of the PAR activators present in the human knee joint will guide study of relevant signaling events and enable future development of novel PAR targeted therapies for OA and other inflammatory joint diseases.

pharmacology and toxicology↗