Prolidase Deficiency Causes Spontaneous T Cell Activation and Lupus-like Autoimmunity.
Rose HodgsonTanya L CrockfordAneesha BhandariJessica D KeppleJennifer BackEleanor CawthorneLucie Abeler-DörnerAdam G LaingSimon ClareAnneliese SpeakDavid J AdamsGordon DouganAdrian C HaydayMukta Deobagkar-LeleRichard J CornallKatherine R BullPublished in: Journal of immunology (Baltimore, Md. : 1950) (2023)
Prolidase deficiency (PD) is a multisystem disorder caused by mutations in the PEPD gene, which encodes a ubiquitously expressed metallopeptidase essential for the hydrolysis of dipeptides containing C-terminal proline or hydroxyproline. PD typically presents in childhood with developmental delay, skin ulcers, recurrent infections, and, in some patients, autoimmune features that can mimic systemic lupus erythematosus. The basis for the autoimmune association is uncertain, but might be due to self-antigen exposure with tissue damage, or indirectly driven by chronic infection and microbial burden. In this study, we address the question of causation and show that Pepd-null mice have increased antinuclear autoantibodies and raised serum IgA, accompanied by kidney immune complex deposition, consistent with a systemic lupus erythematosus-like disease. These features are associated with an accumulation of CD4 and CD8 effector T cells in the spleen and liver. Pepd deficiency leads to spontaneous T cell activation and proliferation into the effector subset, which is cell intrinsic and independent of Ag receptor specificity or antigenic stimulation. However, an increase in KLRG1+ effector CD8 cells is not observed in mixed chimeras, in which the autoimmune phenotype is also absent. Our findings link autoimmune susceptibility in PD to spontaneous T cell dysfunction, likely to be acting in combination with immune activators that lie outside the hemopoietic system but result from the abnormal metabolism or loss of nonenzymatic prolidase function. This knowledge provides insight into the role of prolidase in the maintenance of self-tolerance and highlights the importance of treatment to control T cell activation.
Keyphrases
- systemic lupus erythematosus
- disease activity
- multiple sclerosis
- regulatory t cells
- drug induced
- dendritic cells
- oxidative stress
- replacement therapy
- induced apoptosis
- ejection fraction
- newly diagnosed
- healthcare
- type iii
- nk cells
- signaling pathway
- prognostic factors
- microbial community
- genome wide
- rheumatoid arthritis
- type diabetes
- stem cells
- endoplasmic reticulum stress
- cell cycle arrest
- patient reported
- mesenchymal stem cells
- skeletal muscle
- high fat diet induced
- dna methylation
- transcription factor
- smoking cessation