Anti-human-TIGIT agonistic antibody ameliorates autoimmune diseases by inhibiting Tfh and Tph cells and enhancing Treg cells.

T cells play important roles in autoimmune diseases, but it remains unclear how to optimally manipulate them. We focused on the T cell immunoreceptor with Ig and ITIM domains (TIGIT), a coinhibitory molecule that regulates and is expressed in T cells. In autoimmune diseases, the association between TIGIT-expressing cells and pathogenesis and the function of human-TIGIT (hu-TIGIT) signalling modification have not been fully elucidated. Here we generated anti-hu-TIGIT agonistic monoclonal antibodies (mAbs) and generated hu-TIGIT knock-in mice to accurately evaluate the efficacy of mAb function. Our mAb suppressed the activation of CD4+ T cells, especially follicular helper T and peripheral helper T cells that highly expressed TIGIT, and enhanced the suppressive function of naïve regulatory T cells. These results indicate that our mAb has advantages in restoring the imbalance of T cells that are activated in autoimmune diseases and suggest potential clinical applications for anti-hu-TIGIT agonistic mAbs as therapeutic agents.

Establishment of X-linked Alport syndrome model mice with a Col4a5 R471X mutation.

Alport syndrome (AS) is an inherited disorder characterized by glomerular basement membrane (GBM) abnormality and development of chronic kidney disease at an early age. The cause of AS is a genetic mutation in type IV collagen, and more than 80% of patients have X-linked AS (XLAS) with mutation in COL4A5. Although the causal gene has been identified, mechanisms of progression have not been elucidated, and no effective treatment has been developed. In this study, we generated a Col4a5 mutant mouse harboring a nonsense mutation (R471X) obtained from a patient with XLAS using clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated system. Col4a5 mRNA and protein expressions were not observed in the kidneys of hemizygous R471X male mice. R471X mice showed proteinuria and hematuria. Pathology revealed progression of glomerulosclerosis and interstitial fibrosis by age. Electron microscopy identified irregular thickening in GBM accompanied by irregular lamination. These observations were consistent with the clinical and pathological features of patients with AS and other established models. In addition, our mice models develop end-stage renal disease at the median age of 28 weeks, much later compared to previous models much more consistent with clinical course of human XLAS. Our models have advantages for future experiments in regard with treatment for human XLAS.

Phospholamban Ablation Using CRISPR/Cas9 System Improves Mortality in a Murine Heart Failure Model.

Sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) and its inhibitory protein called phospholamban (PLN) are pivotal for Ca2+ handling in cardiomyocyte and are known that their expression level and activity were changed in the heart failure patients. To examine whether PLN inhibition can improve survival rate as well as cardiac function in heart failure, we performed PLN ablation in calsequestrin overexpressing (CSQ-Tg) mice, a severe heart failure model, using clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system. According this method, generation rate of PLN wild type mice (PLN copy >0.95) and PLN homozygous knockout (KO) mice (PLN copy <0.05) were 39.1% and 10.5%, respectively. While CSQ overexpression causes severe heart failure symptoms and premature death, a significant ameliorating effect on survival rate was observed in PLN homozygous KO/CSQ-Tg mice compared to PLN wild type/CSQ-Tg mice (median survival days are 55 and 50 days, respectively). Measurement of cardiac function with cardiac catheterization at the age of 5 weeks revealed that PLN ablation improved cardiac function in CSQ-Tg mice without affecting heart rate and blood pressure. Furthermore, increases in atrial and lung weight, an index of congestion, were significantly inhibited by PLN ablation. These results suggest that PLN deletion would be a promising approach to improve both mortality and cardiac function in the heart failure.