Tools that enable functional inhibition of the long-term effects of immunological signalling cascades remain challenging to develop, in part because biological outcomes often arise long after the initiating receptor-ligand interaction and lack accessible experimental readouts. Interleukin-7 (IL-7) cytokine signalling through the IL-7 receptor (IL-7R) exemplifies this problem, as IL-7-mediated survival signals in activated CD4+ T cells emerge over extended timescales, yet play a critical role in human disease. Here, we describe the development of engineered Adhiron binders as molecular tools to inhibit IL-7/IL-7R signalling. Using phage display against glycosylated human IL-7Rα ectodomains, we isolated 23 unique Adhiron binders. From this panel, we identified a lead binder, Adh-42, that binds both soluble and membrane-associated IL-7Rα. Adh-42 inhibited proximal IL-7R signalling events in human cells and abrogated IL-7-mediated rescue from activation-induced cell death in human primary CD4+ T-cell blasts (using a recently developed in vitro assay). Together, these findings demonstrate that Adhiron binders can be used to target a cell-surface cytokine receptor (IL-7R) and selectively inhibit downstream biological outcomes in human primary cells. This work establishes Adhirons as versatile molecular tools for probing IL-7 cytokine signalling and provides a framework to support the design and evaluation of future therapeutic strategies.

Neurological manifestations of systemic sclerosis (SSc), including autonomic dysfunction and peripheral neuropathy, are clinically recognized, but their relationship to SSc tissue injury remains poorly defined. We integrated public SSc blood, PBMC, skin and single-cell transcriptomes with an external human peripheral nerve lesion reference to test whether neuroimmune programs are embedded in immune-vascular-fibrotic remodeling. Across four SSc cohorts, pathway analyses identified recurrent interferon activation and skin-enriched fibrosis/TGF-beta, vascular endothelial, chemokine, complement/phagocytosis, neuroimmune-core and peripheral nerve injury signatures. Rank-AUC, ssGSEA and same-size random gene-set analyses supported these findings, and 22 of 70 curated cohort-signature tests remained significant after global Benjamini-Hochberg correction. A 17-gene exploratory score retained moderate discrimination in independent whole blood (AUC = 0.759), but nested cross-validation and stability analyses supported its use as a molecular summary, not a clinical classifier. In GSE250152, 3972 genes were differentially expressed in human peripheral nerve lesions, and lesion-signature projection showed FDR-significant shifts in SSc skin. Single-cell analysis of 146,426 cells localized vascular, fibrotic, interferon, chemokine and selected neuroimmune signals mainly to fibroblast, endothelial, pericyte, T-cell and myeloid-associated skin compartments. Cell-type-frequency adjustment preserved the direction of all 15 highlighted compartment-signature effects, with seven remaining significant after global correction. Ligand-receptor analyses prioritized IL1B-IL1R1, TNF-TNFRSF1A, VEGFA-KDR and TGFB1-TGFBR1 as speculative expression-potential routes rather than demonstrated communication events. These data support a bounded model linking SSc-related neural vulnerability to an immune-vascular-fibrotic neuroimmune niche. Prospective neurologically phenotyped cohorts are required for clinical validation.

Despite triggering IgE-dependent hypersensitivity and being related to the clinically important group 1 allergens of house dust mites (HDMs), the archetypal CA clan cysteine protease, papain, is not an officially denominated allergen. Though lacking formal classification, its ancestral relationship and commercial availability have nevertheless made papain an inviting investigational tool with which to study the role of protease activity in allergy development. However, papain differs sufficiently in substrate specificity from the HDM group 1 allergens for the legitimacy of this premise to be examined. Here, we studied papain as an initiator of a sentinel innate response in a relevant model system whose reactions to the HDM allergome are known. Cultured keratinocytes were loaded with dihydrorhodamine to measure intracellular reactive oxidant species (ROS) production due to papain. Well-characterised pharmacological tools were then used to explore the network activated by this process. Papain evoked an increase in ROS production which required the activation of thrombin and the stimulation of protease-activated receptors 1 and 4 - a finding that was surprising because papain-induced fibrin gelation is not generally attributed to thrombin. Other signalling network components invoked by papain involved epidermal growth factor receptor stimulation, purinoceptor activation, and ligation of both Toll-like receptor (TLR) 1/2 heterodimers and TLR4. The close qualitative parallels between the responses evoked by papain and HDM group 1 allergens indicate that papain engages a shared biosensory and effector network. These findings predict that papain itself may promote allergic sensitisation in humans via the same innate mechanisms.

Our previous study demonstrated that HDAC1 knockdown alleviates traumatic brain injury (TBI), although underlying mechanisms remain unclear. Given the importance of microglial polarization in brain repair and its association with protein lactylation, this study investigated whether neuroprotective effects of HDAC1 inhibition in TBI are mediated through regulation of microglial polarization. In vivo TBI models, in vitro microglial cultures, immunofluorescence, CUT&Tag-seq and RNA-seq were employed to investigate the role of HDAC1 in TBI and its effects on microglial polarization and histone lactylation. Following TBI, microglia exhibited a predominant M1 phenotype with elevated HDAC1 expression, reduced histone lactylation, and altered expression of CD86 and CD206. Pharmacological inhibition of HDAC1, particularly with suberoylanilide hydroxamic acid (SAHA), or lactate supplementation restored histone lactylation and promoted M2 polarization. CUT&Tag-seq and qRT-PCR revealed that HDAC1 inhibition increased histone lactylation at the Gria1 promoter, leading to Gria1 upregulation in microglia. Hyperlactylated genes were enriched in neuroactive ligand-receptor interaction pathway. Overexpression of Gria1 in BV2 cells promoted M2 polarization, characterized by increased CD206 and decreased CD86 expression, which was further enhanced by HDAC1 inhibition or lactate treatment. RNA-seq identified SPP1 as a key downstream effector of Gria1 involved in immune and inflammatory responses. Knockdown of SPP1 suppressed CD206 and abolished the M2 polarization induced by Gria1 overexpression and HDAC1 inhibition. In a mouse TBI model, SAHA improved neurological recovery, reduced cortical lesions, upregulated Gria1 and SPP1, increased CD206, decreased CD86, and attenuated microglial activation. Collectively, pharmacological inhibition of HDAC1-mediated histone delactylation at the Gria1 promoter enhances Gria1-dependent SPP1 expression, thereby promoting microglial M2 polarization and attenuating neuroinflammation after TBI.

Unexpected phosgene exposure poses a significant risk for acute lung injury (ALI), a life-threatening condition associated with high mortality. The key pathological hallmarks of ALI include pulmonary inflammation, alveolar edema, and epithelial cell apoptosis. Spondin 2 (SPON2) is involved in multiple essential biological processes. However, its role in phosgene-induced ALI and the underlying mechanism are still unclear. In the present study, we observed the significant upregulation of SPON2 expression in pulmonary epithelial cells 24 h after phosgene exposure with a murine model of phosgene-induced ALI. Moreover, adeno-associated virus-mediated SPON2 knockdown attenuated inflammatory cell infiltration and alveolar collapse, reduced IL-6, enhanced IL-10 levels, and decreased apoptosis in the lungs of phosgene-exposed mice. SPON2 suppression also mitigated the inflammatory response and apoptosis in MLE-12 cells exposed to lipopolysaccharide. Furthermore, JAK1 and STAT3 phosphorylation levels were significantly increased following lipopolysaccharide stimulation and markedly reduced upon SPON2 inhibition, indicating that SPON2 is associated with the JAK1/STAT3 signaling pathway. These findings suggest that SPON2 suppression attenuates phosgene-induced ALI by regulating both the inflammatory response and apoptosis potentially involving the JAK1/STAT3 pathway. Therefore, this study suggests potential therapeutic strategies for patients with phosgene-induced ALI.

Eosinophils play an essential role in intestinal homeostasis, yet the mechanisms governing their functions in intestine remain poorly defined. β-Glucan, an immunomodulator, has been shown to alleviate colitis, but whether it acts through eosinophils and the underlying mechanisms remains unclear. Here we show that β-Glucan pretreatment significantly attenuated dextran sulfate sodium (DSS)‑induced colitis in wild-type mice but not in eosinophil-deficient mice, indicating an eosinophil-dependent protective effect. β‑Glucan increased the frequency and absolute number of colonic active eosinophils (A-Eos), which correlated with reduced disease severity. Mechanistically, β‑glucan upregulated interleukin-33 (IL‑33) expression in colon tissues. Colon conditioned medium (CM) from β‑glucan‑treated mice directly promoted the differentiation of bone marrow‑derived eosinophils (BM-Eos) into CD80[+]PD‑L1[+] A‑Eos ex vivo, and this effect was completely reversed by IL-33 neutralization. Our findings identify a novel β-glucan-IL-33-A-Eos axis and provide a mechanistic basis for using β-glucan as an immunomodulatory strategy to prevent inflammatory bowel disease (IBD).

Antibody polyreactivity, defined as the ability of a single antibody molecule to recognize multiple unrelated antigens, is a common feature of the human antibody repertoire and contributes to immune defense and homeostasis. In addition to naturally occurring polyreactivity, antibodies can acquire inducible polyreactivity following exposure to environmental factors such as heme, ferrous ions, reactive oxygen species, or protein-destabilizing conditions. Although this "cryptic" polyreactivity is thought to arise in inflammatory and hemolytic settings, its relationship with natural polyreactivity remains poorly understood. In this commentary, we examine whether cryptic polyreactivity represents an amplification of pre-existing antigen-binding promiscuity or instead emerges de novo in otherwise monospecific antibodies. Analyses of clinical-stage therapeutic antibody repertoires indicate that heme- or ferrous ion-induced polyreactivity does not correlate with baseline natural polyreactivity, suggesting that these phenomena are largely mechanistically distinct. However, heme can enhance the promiscuous antigen recognition of certain naturally polyreactive broadly neutralizing anti-HIV-1 antibodies, underscoring the complexity of this phenomenon. A better understanding of the relationship between natural and cryptic antibody polyreactivity may help identify hidden liabilities in therapeutic antibodies and provide new insight into the adaptive flexibility of humoral immunity.

Chronic prostatitis (CP) is common in young males. The etiology is unclear and treatment options are limited. Pyroptosis, a newly identified type of cell death, has been linked to CP pathogenesis, warranting further investigation. Here, the therapeutic effects of artemisinin (ART) on chronic non-specific inflammation were assessed. Comprehensive analyses, including evaluation of chronic pain progression, histopathology, and cytokine levels, revealed that ART significantly and dose-dependently suppressed NOD-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis and alleviated pathological damage in experimental autoimmune prostatitis. Mechanistic studies indicated that ART markedly reduced oxidative stress in autoimmune mouse models by stimulating the Nrf2/HO-1 axis. The effects of ART were blocked by a specific Nrf2/HO-1 inhibitor, preventing inflammasome-mediated induction of pyroptosis. Cellular experiments showed that ART elevated Nrf2 levels and suppressed NLRP3 inflammasome-mediated pyroptosis in RAW264.7 macrophages following lipopolysaccharide (LPS) stimulation. In summary, ART mitigates CP by modulating the Nrf2/HO-1 pathway, thereby reducing oxidative stress and suppressing NLRP3-inflammasome-induced pyroptosis.