Biology subjects

Gitomer, B. Y.

Publications and source records attributed to Gitomer, B. Y..

2 recordsLinked to original sources

bioRxiv2022

The Tryptophan Metabolizing Enzyme Indoleamine 2,3-Dioxygenase 1 Regulates Polycystic Kidney Disease Progression

Autosomal dominant polycystic kidney disease (ADPKD), the most common monogenic nephropathy, is characterized by phenotypic variability exceeding genic effects. Dysregulated metabolism and immune cell function are key disease modulators. The tryptophan metabolites, kynurenines, produced through IDO1, are known immunomodulators. Here, we study the role of tryptophan metabolism in PKD using an orthologous disease model (C57Bl/6J Pkd1RC/RC). We found elevated kynurenine and IDO1 levels in Pkd1RC/RC kidneys versus wildtype. Further, IDO1 levels were increased in ADPKD cell lines and patient cyst cells. Genetic Ido1 loss in Pkd1RC/RC animals resulted in reduced PKD severity as measured by %kidney weight/body weight and cystic index. Consistent with a immunomodulatory role of kynurenines, Pkd1RC/RC;Ido1-/- mice presented with significant changes in the cystic immune microenvironment (CME) versus controls. Of note, kidney macrophage numbers decreased and CD8+ T cell numbers increased, both known PKD modulators. Also, pharmacological IDO1 inhibition using a tryptophan analog in Pkd1RC/RC animals resulted in less severe PKD versus controls with similar changes in the CME as in the genetic model. Together, our data suggest that tryptophan metabolism is dysregulated in ADPKD and that its inhibition results in changes to the CME and slows disease progression, making IDO1 a novel therapeutic target for ADPKD.

molecular biology↗

bioRxiv2022

Immune Checkpoint Activity Regulates Polycystic Kidney Disease Progression

Innate and adaptive immune cells modulate Autosomal Dominant Polycystic Kidney Disease (ADPKD) severity, a common kidney disease with inadequate treatment options. ADPKD shares parallels with cancer where immune checkpoint inhibitors have been shown to reactivate CD8+ T cells and slow tumor growth. We have shown that, in PKD, CD8+ T cell loss worsens disease. This study used orthologous early-onset and adult-onset ADPKD models (Pkd1 p.R3277C) to evaluate the role of immune checkpoints in PKD. Flow cytometry of kidney cells showed increased levels of PD-1 on CD8+ T cells and PD-L1 on macrophages and epithelial cells in Pkd1RC/RC mice versus wildtypes, paralleling disease severity. PD-L1 was also upregulated in ADPKD human cells and patient kidney tissue versus controls. Genetic PD-L1 loss or treatment with an anti-PD-1 antibody did not impact PKD severity in early-onset or adult-onset ADPKD models. However, treatment with anti-PD-1 plus anti-CTLA-4, blocking two immune checkpoints, improved PKD outcomes in adult-onset ADPKD mice; neither monotherapy altered PKD. Combination therapy resulted in increased kidney CD8+ T cell numbers/activation and decreased kidney regulatory T cell numbers. Together, our data suggests that immune checkpoint activation is an important feature of and potential novel therapeutic target in ADPKD.

immunology↗