Biology subjects

Fiset, B.

Publications and source records attributed to Fiset, B..

3 recordsLinked to original sources

bioRxiv2023

Synovial macrophage activation mediates pain experiences in experimental knee osteoarthritis

It has been suggested that synovial macrophages mediate nociceptive signals in knee osteoarthritis (OA) but the underlying mechanisms are unknown. Our objectives were to investigate the role of synovial macrophages and their activation via signal transducer and activator of transcription (STAT) signaling in mediating OA pain experiences. We induced experimental OA in rats via knee destabilization surgery and then performed RNA sequencing analysis in sorted synovial macrophages to identify signaling pathways associated with macrophage activation. Next, we repeated intra-articular injections of liposomal clodronate to deplete macrophages, or liposomal inhibitors of STAT1 or STAT6 to block macrophage activation, and tested the effects on local and distal mechanical pain sensitivity. We also assessed synovitis, cartilage damage, and synovial macrophage infiltration with histopathology and immunofluorescence, and crosstalk between liposomal drug-treated synovium and articular chondrocytes in co-culture. Most enriched signaling pathways in activated OA macrophages involved STAT signalling. Macrophage depletion and STAT6 inhibition led to marked, sustained improvements in mechanical pain sensitivity and synovial inflammation compared to controls, but macrophage depletion caused increased synovial fibrosis and vascularization. In contrast, STAT1 and STAT6 inhibition in macrophages did not worsen synovial or cartilage pathology. In crosstalk assays, macrophage STAT1-inhibited synovium caused the greatest increases in the expression of anabolic and catabolic chondrocyte genes and sulphated glycosaminoglycan secretion in chondrocytes. Our results suggest that synovial macrophages play a key role in mediating pain experiences in experimental knee OA, and that selectively blocking STAT6 in synovial macrophages may reduce OA-related pain without accelerating joint tissue damage. (248/250) One Sentence SummarySelective drug targeting to synovial macrophages improves pain experiences in surgical joint destabilization-induced experimental rodent knee OA. (145/150)

physiology↗

bioRxiv2022

Machine learning meets classical computer vision for accurate cell identification

High-parameter multiplex immunostaining techniques have revolutionized our ability to image healthy and diseased tissues with unprecedented depth; however, accurate cell identification and segmentation remain significant downstream challenges. Identifying individual cells with high precision is a requisite to reliably and reproducibly interpret acquired data. Here we introduce CIRCLE, a cell identification pipeline that combines classical and modern machine learning-based computer vision algorithms to address the shortcomings of current cell segmentation tools for 2D images. CIRCLE is a fully automated hybrid cell detection model, eliminating subjective investigator bias and enabling high-throughput image analysis. CIRCLE accurately distinguishes cells across diverse tissues microenvironments, resolves low-resolution structures, and can be applied to any 2D image that contains nuclei. Importantly, we quantitatively demonstrate that CIRCLE outperforms current state-of-the-art image segmentation tools using multiple accuracy measures. As high-throughput multiplex imaging grows closer toward standard practice for histology, integration of CIRCLE into analysis protocols will deliver unparalleled segmentation quality.

cell biology↗

bioRxiv2021

Met-HER3 crosstalk supports proliferation via MPZL3 in MET-amplified cancer cells

Receptor tyrosine kinases (RTKs) are recognized as targets of precision medicine in human cancer upon their gene amplification or constitutive activation, resulting in increased downstream signal complexity including heterotypic crosstalk with other RTKs. The Met RTK exhibits such reciprocal crosstalk with several members of the human EGFR (HER) family of RTKs when amplified in cancer cells. We show that Met signaling converges on HER3 tyrosine phosphorylation across a panel of seven MET-amplified cancer cell lines and that HER3 is required for cancer cell expansion and oncogenic capacity in-vitro and in-vivo. Gene expression analysis of HER3-depleted cells identified MPZL3, encoding a single-pass transmembrane protein, as a HER3-dependent effector in multiple MET-amplified cancer cell lines. MPZL3 interacts with HER3 and MPZL3 loss phenocopies HER3 loss in MET-amplified cells, while MPZL3 overexpression rescues proliferation upon HER3 depletion. Together, these data support an oncogenic role for a HER3-MPZL3 axis in MET-amplified cancers.

cancer biology↗