Mucopolysaccharidosis type II (OMIM 309900) is a lysosomal storage disorder caused by iduronate 2-sulfatase (IDS) deficiency and accumulation of glycosaminoglycans, leading to progressive neurodegeneration. As intravenously infused enzyme replacement therapy cannot cross the blood-brain barrier (BBB), it fails to treat brain pathology, highlighting the unmet medical need to develop alternative therapies. Here, we test modified versions of hematopoietic stem and progenitor cell (HSPC)-mediated lentiviral gene therapy (LVGT) using IDS tagging in combination with the ubiquitous MND promoter to optimize efficacy in brain and to investigate its mechanism of action. We find that IDS tagging with IGF2 or ApoE2, but not RAP12x2, improves correction of brain heparan sulfate and neuroinflammation at clinically relevant vector copy numbers. HSPC-derived cells engrafted in brain show efficiencies highest in perivascular areas, lower in choroid plexus and meninges, and lowest in parenchyma. Importantly, the efficacy of correction was independent of the number of brain-engrafted cells. These results indicate that tagged versions of IDS can outperform untagged IDS in HSPC-LVGT for the correction of brain pathology in MPS II, and they imply both cell-mediated and tag-mediated correction mechanisms, including passage across the BBB and increased uptake, highlighting their potential for clinical translation.
© 2023 The Authors.

Regulatory T cells (Tregs) are protective in atherosclerosis but reduced during disease progression due to cell death and loss of stability. However, the mechanisms of Treg dysfunction remain unknown. Oxidized phospholipids are abundant in atherosclerosis and can activate innate immune cells, but little is known regarding their impact on T cells. Given Treg loss during atherosclerosis progression and oxidized phospholipid levels in the plaque microenvironment, we investigated whether oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (oxPAPC), an oxidized phospholipid associated with atherosclerotic plaques, alters Treg differentiation and function.
CD4+ T cells were polarized to Treg, T helper (Th) 1, and Th17 cells with or without oxPAPC and assessed by flow cytometry. Gene expression in oxPAPC-treated Tregs was analyzed by bulk RNA sequencing. Functional studies of oxPAPC-induced Tregs were performed by coculturing Tregs with CellTrace Violet-labeled cells in vitro, and by adoptively transferring Tregs to hyperlipidemic Ldlr-/- mice to measure atherosclerosis progression.
Compared with controls, oxPAPC-treated Tregs were less viable, but surviving cells expressed higher levels of the Th1-associated markers T-bet, CXCR3, and IFN (interferon)-γ. Th1 and Th17 skewing cultures were unaltered by oxPAPC. IFN-γ is linked to Treg instability, thus Treg polarization experiments were repeated using Ifngr1-/- CD4+ T cells. IFNγR1 (INF gamma receptor 1) deficiency did not improve cell viability in oxPAPC-treated Tregs; however, T-bet and IFN-γ expression was not increased in surviving cells suggesting a role for IFN-γsignaling. OxPAPC-treated Tregs were less suppressive in vitro, and adoptive transfer studies in hyperlipidemic Ldlr-/- mice showed that oxPAPC-induced Tregs possessed altered tissue homing and were insufficient to inhibit atherosclerosis progression.
OxPAPC elicits Treg-specific changes altering Treg differentiation and inducing a Th1-like phenotype in surviving cells partially through IFN-γ signaling. This is biologically relevant as oxPAPC-treated Tregs do not reduce atherosclerosis progression in Ldlr-/- mice. This study supports the role of oxidized phospholipids in negatively impacting Treg differentiation and atheroprotective function.

Amongst other systemic changes, aging leads to an immune dysfunction. On the molecular level, a hallmark of aging is telomere shortening. The functional relevance of telomerase, an enzyme capable of elongating telomeres in T cells upon antigen stimulation, is not fully understood. Studying the impact of telomere shortening on CD4+ T cells and especially Th1 effector function can provide a better understanding on immune dysfunctions in elderly.
We investigated T cell numbers and differentiation in telomerase-deficient (mTerc-/-) mice under steady-state conditions and the functional role of telomerase in CD4+ T cells using in vitro stimulation and Th1 polarization protocols by comparing T cells from mTerc-/- and control mice. We report reduced relative CD4+ T cell numbers in blood and secondary lymphoid organs and a relative decline in the naïve T cell population in thymus, blood and spleen of mTerc-/- mice compared to control mice. Importantly, after in vitro polarization, mTerc-/- G3 CD4+ T cells showed higher numbers of IFNγ-producing cells and reduced expression of CD28. Notably, telomerase-deficient T cells were more susceptible to inhibition of Th1 polarization by IL-6 in vitro. These results demonstrate that telomerase deficiency recapitulates several changes of CD4+ T cells seen in aged humans regarding the naïve T cell population, expression of CD28 and cytokine production.
Our data suggest that telomere shortening could play a key role in the aging of T cell immunity, with clinical implications for immune diseases and tumor development and that mTerc-/- mice are a suitable model to study aging-related defects of adaptive immunity.
© 2022. The Author(s).

Interleukin (IL)-22 is central to immune defense at barrier sites. We examined the contributions of innate lymphoid cell (ILC) and T cell-derived IL-22 during Citrobacter rodentium (C.r) infection using mice that both report Il22 expression and allow lineage-specific deletion. ILC-derived IL-22 activated STAT3 in C.r-colonized surface intestinal epithelial cells (IECs) but only temporally restrained bacterial growth. T cell-derived IL-22 induced a more robust and extensive activation of STAT3 in IECs, including IECs lining colonic crypts, and T cell-specific deficiency of IL-22 led to pathogen invasion of the crypts and increased mortality. This reflected a requirement for T cell-derived IL-22 for the expression of a host-protective transcriptomic program that included AMPs, neutrophil-recruiting chemokines, and mucin-related molecules, and it restricted IFNγ-induced proinflammatory genes. Our findings demonstrate spatiotemporal differences in the production and action of IL-22 by ILCs and T cells during infection and reveal an indispensable role for IL-22-producing T cells in the protection of the intestinal crypts.
Copyright © 2022 Elsevier Inc. All rights reserved.

In the pathogenesis of autoimmune disorders, the modulation of leukocytes' trafficking plays a central role, still poorly understood. Here, we focused on the effect of TLR2 ligands in trafficking of T helper cells through reshuffling of CD44 isoforms repertoire. Concurrently, strain background and TLR2 haplotype affected Wnt/β-catenin signaling pathway and expression of splicing factors. During EAE, mCD44 v9- v 10 was specifically enriched in the forebrain and showed an increased ability to bind stably to osteopontin. Similarly, we observed that hCD44 v7 was highly enriched in cells of cerebrospinal fluid from MS patients with active lesions. Moreover, TLRs engagement modulated the composition of CD44 variants also in human T helper cells, supporting the hypothesis that pathogens or commensals, through TLRs, in turn modulate the repertoire of CD44 isoforms, thereby controlling the distribution of lesions in the CNS. The interference with this mechanism(s) represents a potential tool for prevention and treatment of autoimmune relapses and exacerbations.
© 2022 The Authors.