CD4+ T-Cell Legumain Deficiency Attenuates Hypertensive Damage via Preservation of TRAF6

Circ Res. 2024 Jan 5;134(1):9-29. doi: 10.1161/CIRCRESAHA.123.322835. Epub 2023 Dec 4.

Abstract

Background: T cells are central to the immune responses contributing to hypertension. LGMN (legumain) is highly expressed in T cells; however, its role in the pathogenesis of hypertension remains unclear.

Methods: Peripheral blood samples were collected from patients with hypertension, and cluster of differentiation (CD)4+ T cells were sorted for gene expression and Western blotting analysis. TLGMNKO (T cell-specific LGMN-knockout) mice (Lgmnf/f/CD4Cre), regulatory T cell (Treg)-specific LGMN-knockout mice (Lgmnf/f/Foxp3YFP Cre), and RR-11a (LGMN inhibitor)-treated C57BL/6 mice were infused with Ang II (angiotensin II) or deoxycorticosterone acetate/salt to establish hypertensive animal models. Flow cytometry, 4-dimensional label-free proteomics, coimmunoprecipitation, Treg suppression, and in vivo Treg depletion or adoptive transfer were used to delineate the functional importance of T-cell LGMN in hypertension development.

Results: LGMN mRNA expression was increased in CD4+ T cells isolated from hypertensive patients and mice, was positively correlated with both systolic and diastolic blood pressure, and was negatively correlated with serum IL (interleukin)-10 levels. TLGMNKO mice exhibited reduced Ang II-induced or deoxycorticosterone acetate/salt-induced hypertension and target organ damage relative to wild-type (WT) mice. Genetic and pharmacological inhibition of LGMN blocked Ang II-induced or deoxycorticosterone acetate/salt-induced immunoinhibitory Treg reduction in the kidneys and blood. Anti-CD25 antibody depletion of Tregs abolished the protective effects against Ang II-induced hypertension in TLGMNKO mice, and LGMN deletion in Tregs prevented Ang II-induced hypertension in mice. Mechanistically, endogenous LGMN impaired Treg differentiation and function by directly interacting with and facilitating the degradation of TRAF6 (tumor necrosis factor receptor-associated factor 6) via chaperone-mediated autophagy, thereby inhibiting NF-κB (nuclear factor kappa B) activation. Adoptive transfer of LGMN-deficient Tregs reversed Ang II-induced hypertension, whereas depletion of TRAF6 in LGMN-deficient Tregs blocked the protective effects.

Conclusions: LGMN deficiency in T cells prevents hypertension and its complications by promoting Treg differentiation and function. Specifically targeting LGMN in Tregs may be an innovative approach for hypertension treatment.

Keywords: TNF receptor-associated factor 6; angiotensin II; hypertension; interleukins; kidney.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / adverse effects
  • Acetates / metabolism
  • Angiotensin II / metabolism
  • Angiotensin II / toxicity
  • Animals
  • CD4-Positive T-Lymphocytes / metabolism
  • Desoxycorticosterone / adverse effects
  • Desoxycorticosterone / metabolism
  • Humans
  • Hypertension* / chemically induced
  • Hypertension* / genetics
  • Hypertension* / prevention & control
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • T-Lymphocytes, Regulatory
  • TNF Receptor-Associated Factor 6* / metabolism

Substances

  • Acetates
  • Angiotensin II
  • asparaginylendopeptidase
  • Desoxycorticosterone
  • TNF Receptor-Associated Factor 6
  • TRAF6 protein, mouse

Supplementary concepts

  • Thymic aplasia