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Biomedical subjects

Laszlo Halasz

Publications and source records attributed to Laszlo Halasz.

3 recordsLinked to original sources

Dendritic cells control tertiary lymphoid structure development and maintenance in cancer.

Tertiary lymphoid structures (TLSs) are associated with immunotherapy response, yet the mechanisms controlling their formation and maintenance remain unclear. Using spatial transcriptomics and multiplex imaging across human tumors, we found that CCR7+ mature dendritic cells (DCs) accumulate in TLSs. In a mouse non-small cell lung cancer model that forms mature TLSs, we show that early TLS development requires interferon-γ (IFN-γ)-driven type 1 conventional dendritic cell (cDC1) maturation, migration to tumor-draining lymph nodes (tdLNs), and T cell recruitment. As tumors progress, TLSs persist independently of tdLN T cell egress, coinciding with cDC1 accumulation within intratumoral CCL19 stromal hubs. There, cDC1-major histocompatibility complex class 1 (MHC-I) and -MHC-II concomitant antigen presentation, along with CD40 signaling, sustain TLS, T follicular helper (TFH) cell pool, germinal centers, and tumor-specific immunoglobulin G (IgG). These findings highlight local mature cDC1s as key TLS orchestrators and potential targets to enhance antitumor TLS function.

Animals

BACH1 orchestrates macrophage state transitions to coordinate regenerative inflammation.

Efficient tissue regeneration requires the precise coordination of inflammatory and regenerative programs, principally mediated by monocyte-derived macrophages. However, the transcriptional wiring and epigenomic processes behind complex macrophage subtype specification and transition between the different states are not known. Here we have identified the transcriptional repressor BACH1 as a critical, cell-intrinsic regulator of monocyte-derived macrophage specification during skeletal muscle regeneration. Using a myeloid-specific BACH1 knockout mouse model, we demonstrate that BACH1 deficiency disrupts the temporal coordination of monocyte-to-macrophage differentiation, leading to aberrant macrophage subsets with concurrent opposing pro- and anti-inflammatory features. Single-cell RNA-sequencing profiling reveals that BACH1 controls a core transcriptional network, including Nfkb1, Cebpb, and interferon signaling, governing inflammatory resolution and functional macrophage specialization. Mechanistically, BACH1 loss accelerates macrophage differentiation but also affects its core cellular identity, resulting in sustained, rather than declining inflammatory programs including upregulation of Il1b and thus, defective tissue remodeling. These immune alterations compromise the paracrine landscape during regenerative inflammation and impair muscle stem cell differentiation. Our findings establish BACH1 as a molecular tuner or controller that integrates early innate immune signaling with regenerative output, positioning it as a central node linking transcriptional control, immune fate decisions, and tissue repair.

Animals

Setdb2 Regulates Inflammatory Trigger-Induced Trained Immunity of Macrophages Through Two Different Epigenetic Mechanisms.

"Trained immunity" of innate immune cells occurs through a sequential two-step process where an initial pathogenic or sterile inflammatory trigger is followed by an amplified response to a later un-related secondary pathogen challenge. The memory effect is mediated at least in part through epigenetic modifications of the chromatin landscape. Here, we investigated the role of the epigenetic modifier Setdb2 in microbial (β-glucan) or sterile trigger (Western-diet-WD/oxidized-LDL-oxLDL)-induced trained immunity of macrophages. Using genetic mouse models and genomic analysis, we uncovered a critical role of Setdb2 in regulating proinflammatory and metabolic pathway reprogramming. We further show that Setdb2 regulates trained immunity through two different complementary mechanisms: one where it positively regulates glycolytic and inflammatory pathway genes via enhancer-promoter looping, and is independent of its enzymatic activity; while the second mechanism is associated with both increased promoter associated H3K9 methylation and repression of interferon response pathway genes. Interestingly, while both mechanisms occur in response to pathogenic training, only the chromatin-looping mechanism operates in response to the sterile inflammatory stimulus. These results reveal a previously unknown bifurcation in the downstream pathways that distinguishes between pathogenic and sterile inflammatory signaling responses associated with the innate immune memory response and may provide potential therapeutic opportunities to target cytokine vs. interferon pathways to limit complications of chronic inflammation.

Setdb2