Congratulations to Manpreet Semwal, PhD on her first author publication in PNAS!

Dr. Semwal is an Postdoctoral Research Fellow in the lab of Dr. Nicolas Musi with the Sam and Ann Barshop Institute for Longevity and Aging Studies.

Redox status regulates autophagy in thymic stromal cells and promotes T cell tolerance
Manpreet K Semwal, Allison K Hester, Yangming Xiao, Chioma Udeaja, Sergio Cepeda, John S Verschelde 2nd, Nicholas Jones, Sarah A Wedemeyer, Simon Emtage, Kymberly Wimberly, Ann V Griffith.
Proc Natl Acad Sci U S A. 2022 Oct 4;119(40):e2204296119. doi: 10.1073/pnas.2204296119. Epub 2022 Sep 26.


Thymic stromal cells (TSCs) are critical regulators of T cell tolerance, but their basic biology has remained under-characterized because they are relatively rare and difficult to isolate. Recent work has revealed that constitutive autophagy in TSCs is required for self-antigen presentation and central T cell tolerance induction; however, the mechanisms regulating constitutive autophagy in TSCs are not well understood. Hydrogen peroxide has been shown to increase autophagy flux in other tissues, and we previously identified conspicuously low expression of the hydrogen peroxide-quenching enzyme catalase in TSCs. We investigated whether the redox status of TSCs established by low catalase expression regulates their basal autophagy levels and their capacity to impose central T cell tolerance. Transgenic overexpression of catalase diminished autophagy in TSCs and impaired thymocyte clonal deletion, concomitant with increased frequencies of spontaneous lymphocytic infiltrates in lung and liver and of serum antinuclear antigen reactivity. Effects on clonal deletion and autoimmune indicators were diminished in catalase transgenic mice when autophagy was rescued by expression of the Becn1F121A/F121A knock-in allele. These results suggest a metabolic mechanism by which the redox status of TSCs may regulate central T cell tolerance.

Keywords: thymus; tolerance.


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