Improvement of Lipoplexes With a Sialic Acid Mimetic to Target the C1858T PTPN22 Variant for Immunotherapy in Endocrine Autoimmunity.

Andrea Arena,Riccardo Schiaffini,Olivia Pagliarosi,Peng Wang,Ezio Giorda,Simona Sennato,Francesca Ceccacci,James C Paulson,Giovanna Mancini,Stefania Petrini,Alessandra Fierabracci,Eugenia Belcastro,Libenzio Adrian Conti

doi:10.3389/fimmu.2022.838331

Abstract

The C1858T variant of the protein tyrosine phosphatase N22 (PTPN22) gene is associated with pathophysiological phenotypes in several autoimmune conditions, namely, Type 1 diabetes and autoimmune thyroiditis. The R620W variant protein, encoded by C1858T, leads to a gain of function mutation with paradoxical reduced T cell activation. We previously exploited a novel personalized immunotherapeutic approach based on siRNA delivered by liposomes (lipoplexes, LiposiRNA) that selectively inhibit variant allele expression. In this manuscript, we functionalize lipoplexes carrying siRNA for variant C1858T with a high affinity ligand of Siglec-10 (Sig10L) coupled to lipids resulting in lipoplexes (LiposiRNA-Sig10L) that enhance delivery to Siglec-10 expressing immunocytes. LiposiRNA-Sig10L lipoplexes more efficiently downregulated variant C1858T PTPN22 mRNA in PBMC of heterozygous patients than LiposiRNA without Sig10L. Following TCR engagement, LiposiRNA-Sig10L more significantly restored IL-2 secretion, known to be paradoxically reduced than in wild type patients, than unfunctionalized LiposiRNA in PBMC of heterozygous T1D patients.

Highlights

The incidence of autoimmune diseases is increasing worldwide [1]
As envisaged by several reports, that C1858T protein tyrosine phosphatase N22 (PTPN22) gene polymorphism which changes amino acid Arg (R) 620 to Trp (W) (R620W) in the encoded lymphoid tyrosine phosphatase protein (Lyp) [7, 13] could be a relevant target for immunomodulation in the treatment of patients affected by an autoimmune disease harboring the variant [7, 14]
dynamic light scattering (DLS) analysis showed that both liposomes and lipoplexes, in the presence or in the absence of F9-PEG-Lipid, have a small hydrodynamic diameter (∼ 60 nm, details are reported in Supplementary Materials, Table S1) and are stable up to 48 h

Summary

Introduction

The incidence of autoimmune diseases is increasing worldwide [1]. With reference to endocrine autoimmunity, insulin-dependent diabetes mellitus (Type 1 diabetes, T1D) and autoimmune thyroid diseases (ATD) are the most common endocrinopathies. T1D is caused by the targeted destruction of Targeting C1858T PTPN22 With LiposiRNA-Sig10L insulin-producing beta cells by autoreactive T lymphocytes [3] and especially occurs in children below 5 years of age [4]. This represents the third most common metabolic disorder after obesity and thyroid dysfunction [5, 6]. The only available treatment of the endocrine organ-specific autoimmune disorder is the standard substitutive administration of the deficient hormones, i.e., insulin and levo-thyroxine (L-T4). It would be desirable to have an immunotherapeutic strategy that preserves the hormonal cells from the autoimmune attack halting the pathogenetic mechanism of disease [7]. Several approaches targeting the immune system have already been experimented but without success since insulinindependence was not achieved in diabetic patients [8, 9]

Methods

Results

Conclusion