Remyelination, the process by which axons are re-encased in myelin after injury, is a critical step in restoring brain function, yet the dynamics from initial injury to repair remain poorly characterized. Here, we combined optimized single-nucleus RNA-seq with Slide-seqv2, a high-resolution spatial transcriptomics technology, to densely reconstruct the cellular processes that coordinate remyelination after a focal demyelinating injury. This revealed several findings: First, we found extensive transcriptional diversity of glia and monocyte-derived macrophages from demyelination to repair. Second, we identified a population of infiltrating peripheral lymphocytes—predominantly CD8 T-cells and natural killer cells—that are enriched specifically during remyelination. Third, we identified a concerted interferon-response gene signature that is shared across several cell types—microglia, astrocytes, and the oligodendrocyte lineage—just prior to reestablishment of myelin. These interferon-responsive glia (IRG) form clusters around remyelinating white matter and their formation is solely dependent on the type I interferon receptor. Functionally, we found that IRG secrete the cytokine CXCL10 which mediates infiltration of peripheral lymphocytes into the repairing white matter. Depletion of the most abundant infiltrating lymphocyte, CD8 T-cells, attenuated the differentiation of mature oligodendrocytes during remyelination. Together, our data reveals the diversity of glial-immune interactions that orchestrate white matter repair and a type I-dependent glial state that drives lymphocyte influx into damaged white matter to modulate oligodendrocyte differentiation. Abstract Figure

Sjögren's Disease (SjD) is an autoimmune disease characterized by lymphocytic infiltration of salivary and lacrimal glands (LG). The LG produces the protein-rich aqueous component of tears, and SjD-associated autoimmune dacryoadenitis (AD) may thus alter tear autoantibody composition.
The presence of tertiary lymphoid structures (TLS) in LG from two murine models of SjD-associated AD, male non-obese diabetic (NOD) and male non-obese insulitis resistant (NOR) mice, were evaluated using immunofluorescence. IgG and IgA reactivity in serum and tears from these models were probed in three studies against a panel of 80-120 autoantigens using autoantibody microarrays relative to serum and tears from healthy male BALB/c mice. Sources of Ig in tears were investigated using scRNA-Seq of the LG (GSE132420). Data were analyzed by R package Limma and Seurat.
Analysis of immunofluorescence in LG sections from both SjD models showed TLS. Only one autoantibody was significantly elevated in tears and serum in both SjD models across all studies. Three autoantibodies were significantly elevated in serum but not in tears in both SjD models across all studies. Conversely, six IgG and thirteen IgA autoantibodies (6 sharing the same autoantigen) were significantly elevated in tears but not serum in both SjD models. Igha and Ighg2b expressing cells were identified in the plasma cell cluster of NOD.H2b LG.
NOD and NOR mice with SjD-associated AD have distinct autoantibody profiles in tears and serum. Tear IgA isotype autoantibodies showed a greater diversity than tear IgG autoantibodies. TLS observed in LG are a likely source of the tear autoantibodies.
Copyright © 2025 Singh Kakan, Abdelhamid, Ju, MacKay, Edman, Raman, Zhu, Raj and Hamm-Alvarez.

Peripheral CD8+ T cell tolerance is a checkpoint in both autoimmune disease and anti-cancer immunity. Despite its importance, the relationship between tolerance-induced states and other CD8+ T cell differentiation states remains unclear. Using flow cytometric phenotyping, single-cell RNA sequencing (scRNA-seq), and chromatin accessibility profiling, we demonstrated that in vivo peripheral tolerance to a self-antigen triggered a fundamentally distinct differentiation state separate from exhaustion, memory, and functional effector cells but analogous to cells defectively primed against tumors. Tolerant cells diverged early and progressively from effector cells, adopting a transcriptionally and epigenetically distinct state within 60 h of antigen encounter. Breaching tolerance required the synergistic actions of strong T cell receptor (TCR) signaling and inflammation, which cooperatively induced gene modules that enhanced protein translation. Weak TCR signaling during bystander infection failed to breach tolerance due to the uncoupling of effector gene expression from protein translation. Thus, tolerance engages a distinct differentiation trajectory enforced by protein translation defects.
Copyright © 2024 Elsevier Inc. All rights reserved.

Microglia-mediated synaptic plasticity after CNS injury varies depending on injury severity, but the mechanisms that adjust synaptic plasticity according to injury differences are largely unknown. This study investigates differential actions of microglia on essential spinal motor synaptic circuits following different kinds of nerve injuries. Following nerve transection, microglia and C-C chemokine receptor type 2 signaling permanently remove Ia axons and synapses from the ventral horn, degrading proprioceptive feedback during motor actions and abolishing stretch reflexes. However, Ia synapses and reflexes recover after milder injuries (nerve crush). These different outcomes are related to the length of microglia activation, being longer after nerve cuts, with slower motor-axon regeneration and extended expression of colony-stimulating factor type 1 in injured motoneurons. Prolonged microglia activation induces CCL2 expression, and Ia synapses recover after ccl2 is deleted from microglia. Thus, microglia Ia synapse removal requires the induction of specific microglia phenotypes modulated by nerve regeneration efficiencies. However, synapse preservation was not sufficient to restore the stretch-reflex function.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been demonstrated to play a critical role in regulating cholesterol homeostasis and T cell antitumor immunity. However, the expression, function, and therapeutic value of PCSK9 in head and neck squamous cell carcinoma (HNSCC) remain largely unexplored. Here, we found that the expression of PCSK9 was upregulated in HNSCC tissues, and higher PCSK9 expression indicated poorer prognosis in HNSCC patients. We further found that pharmacological inhibition or siRNA downregulating PCSK9 expression suppressed the stemness-like phenotype of cancer cells in an LDLR-dependent manner. Moreover, PCSK9 inhibition enhanced the infiltration of CD8+ T cells and reduced the myeloid-derived suppressor cells (MDSCs) in a 4MOSC1 syngeneic tumor-bearing mouse model, and it also enhanced the antitumor effect of anti-PD-1 immune checkpoint blockade (ICB) therapy. Together, these results indicated that PCSK9, a traditional hypercholesterolemia target, may be a novel biomarker and therapeutic target to enhance ICB therapy in HNSCC.
© 2023 The Authors.