Biology subjects

Tasegian, A.

Publications and source records attributed to Tasegian, A..

3 recordsLinked to original sources

bioRxiv2024

Regulation of Leucine-Rich Repeat Kinase 2 by inflammation and IL-4

Mutations in Leucine-Rich Repeat protein Kinase 2 (LRRK2) are associated with Parkinsons Disease (PD) and Crohns Disease (CD), but the regulation of LRRK2 during inflammation remains relatively unexplored. Here we developed a flow cytometry-based assay to assess LRRK2 activity in individual cells and created an EGFP-Lrrk2-knock-in reporter mouse to analyse cell-specific LRRK2 expression. Using these tools, we catalogued LRRK2 levels and activity in splenic and intestinal immune cells. Inflammation increased LRRK2 expression and activity in B-cells, immature neutrophils and immature monocytes, but decreased these in dendritic cells and eosinophils. In mature neutrophils, inflammation stimulated activity but reduced LRRK2 expression. A kinase-activating PD-associated LRRK2-R1441C mutation exacerbated inflammation-induced activation of LRRK2 specifically in monocytes and macrophages without affecting LRRK2 levels. Finally, we identified IL-4 as a novel factor that upregulated LRRK2 expression and activity in B-cells, replicating inflammatory effects observed in vivo. Our findings provide valuable new insights into the regulation of the LRRK2 pathway in immune cells, crucial for understanding LRRK2 and its therapeutic potential in inflammatory diseases such as CD.

immunology↗

bioRxiv2024

Leucine Rich Repeat Kinase 2 is not required for lysozyme expression in intestinal Paneth cells

Genetic variants in Leucine-rich Repeat Kinase 2 (LRRK2) gene have been linked to Parkinsons disease (PD) and are also associated with inflammatory bowel diseases (IBD), specifically Crohns disease (CD), a transmural inflammation that can affect the entire length of the gastrointestinal tract and is commonly seen in the ileum1. In ileal CD, defects in specialized intestinal epithelial cells known as Paneth cells are believed to drive disease pathogenesis2,3. Paneth cells contribute to mucosal defense by secreting antimicrobial peptides including lysozyme and to the maintenance of intestinal stem cells by secreting growth factors. A previous article published by Zhang et al4 in Nature Immunology identified a key role for LRRK2 in selective sorting and secretion of lysozyme in Paneth cells. However, after extended analyses, we find that LRRK2 is not required for lysozyme expression in the murine gut and is not expressed in either murine or human Paneth cells.

physiology↗

bioRxiv2021

Impact of Type II LRRK2 inhibitors on signalling and mitophagy

Much effort has been devoted to the development of selective inhibitors of the LRRK2 as a potential treatment for LRRK2 driven Parkinsons disease. In this study we first compare the properties of Type I (GSK3357679A and MLi-2) and Type II (GZD-824, Rebastinib and Ponatinib) kinase inhibitors that bind to the closed or open conformations of the LRRK2 kinase domain, respectively. We show that Type I and Type II inhibitors suppress phosphorylation of Rab10 and Rab12, key physiological substrates of LRRK2 and also promote mitophagy, a process suppressed by LRRK2. Type II inhibitors also display higher potency towards wild type LRRK2 compared to pathogenic mutants. Unexpectedly, we find that Type II inhibitors, in contrast to Type I compounds, fail to induce dephosphorylation of a set of well-studied LRRK2 biomarker phosphorylation sites at the N-terminal region of LRRK2, including Ser935. These findings emphasize that the biomarker phosphorylation sites on LRRK2 are likely reporting on the open vs closed conformation of LRRK2 kinase and that only inhibitors which stabilize the closed conformation induce dephosphorylation of these biomarker sites. Finally, we demonstrate that the LRRK2[A2016T] mutant which is resistant to MLi-2 Type 1 inhibitor, also induces resistance to GZD-824 and Rebastinib suggesting this mutation could be exploited to distinguish off target effects of Type II inhibitors. Our observations provide a framework of knowledge to aide with the development of more selective Type II LRRK2 inhibitors.

neuroscience↗