The cholinergic antiinflammatory pathway attenuates lung inflammation via the α7 nicotinic acetylcholine receptor (α7 nAChR) on immune cells. However, the role of α7 nAChR on lung megakaryocytes (Mks) in allergic airway inflammation remains unknown. In this study, allergen-challenged mouse models were used with conditional Mk-specific Chrna7 knockout, pharmacological activation (GTS-21), and Mk reconstitution. IL-33 expression and p38 MAPK signaling were assessed. We found that allergen challenge upregulated α7 nAChR specifically in lung Mks. Mk-specific Chrna7 deletion significantly alleviated allergic airway inflammation, whereas GTS-21 exacerbated inflammation via an Mk-dependent mechanism. Reconstitution with α7 nAChR + Mks restored airway inflammatory responses. Mechanistically, α7 nAChR activation promoted Mk IL-33 synthesis and secretion through p38 MAPK signaling. Taken together, our results show that α7 nAChR on lung Mks plays a proinflammatory role in allergic airway inflammation, challenging its classical antiinflammatory paradigm and revealing pathogenic mechanisms.

Renal metabolomics and molecular biology techniques were employed to investigate the interventional effect and underlying mechanism of Qingxin Lianzi Decoction(QXLZ) in rats with diabetic kidney disease(DKD). Sprague-Dawley rats were randomly assigned to the following groups: a blank group, a model group, a metformin(0.2 g·kg~(-1)) group, and QXLZ low-, medium-, and high-dose groups(10, 20, and 40 g·kg~(-1), respectively). The DKD model was established in all groups except the blank group by feeding with a high-fat diet combined with intraperitoneal injection of streptozotocin(STZ, 30 mg·kg~(-1)). After successful modeling, the rats received the corresponding treatments by oral gavage for six consecutive weeks. Upon completion of the intervention, random blood glucose levels were measured to assess the glucose-regulating capacity of QXLZ in DKD rats. Renal histopathological changes and fibrosis degree were evaluated by hematoxylin-eosin, Masson's trichrome, and periodic acid-Schiff staining. Renal function indicators(24-hour urinary total protein [24h-UTP], blood urea nitrogen [BUN], creatinine [Cr]) were measured by biochemical assays. The levels of blood glucose(glycated hemoglobin [GHb]), inflammatory markers(tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β]), and fibrosis markers(collagen type Ⅳ [Col Ⅳ], α-smooth muscle actin [α-SMA]) were detected by enzyme-linked immunosorbent assay. Immunofluorescence was used to determine the expression of TNF-α, IL-1β, α-SMA, and Col Ⅳ in renal tissues. Metabolomics was applied to identify differentially expressed metabolites in renal tissues. The results showed that compared with the blank group, the model group showed significant increases in several key indicators, including random blood glucose and GHb reflecting glucose metabolism, 24h-UTP, BUN, and Cr assessing renal function, as well as the inflammatory cytokines TNF-α and IL-1β and the fibrosis markers Col Ⅳ and α-SMA(P<0.05). The renal histology also exhibited typical features of DKD. Compared with the model group, all intervention groups showed significant reductions in these indicators, along with decreased collagen deposition and inflammatory resolution. Metabolomic analysis revealed that the intervention of QXLZ in DKD was closely associated with the arachidonic acid metabolism pathway. In conclusion, QXLZ effectively regulates blood glucose, improves renal function, and ameliorates renal inflammation and fibrotic injury in DKD rats, and its mechanism may be related to the arachidonic acid metabolic pathway.

Allergic airway inflammation involves complex neuro‑immune interactions, yet the role of α2A‑adrenergic receptors (α2AR, encoded by Adra2a) in Tfh development and type 2 immunity remains poorly defined. HDM‑induced asthma model was established in C57BL/6 mice. RNA‑sequencing, correlation analysis, flowcytometry, immunofluorescence, and pharmacological interventions were used. Il33 knockout mice and T‑cell‑specific Adra2a or Akt1 knockout mice were generated. GEO datasets were analyzed for Tfh cell signatures. We found that HDM challenge significantly upregulated Adra2a in lung and lymph nodes. Adra2a expression was strongly correlated with type 2 chemokines Ccl11, Il33, and Ccl17. In Il33KO mice, Adra2a was among the top downregulated genes, and Il33 deletion broadly suppressed type 2 inflammation genes. Catecholamine‑metabolizing enzymes showed differential correlations: Maoa positively correlated with Adra2a and asthma genes, whereas Maob and Ddc were negatively correlated. α2AR was highly expressed on Tfh cells, especially on GC‑Tfh cells. α2AR activation aggravated airway inflammation, increased Tfh and germinal center B cells, promoted type 2 cytokines and IgE, and AKT phosphorylation. Conversely, T‑cell‑specific Adra2a knockout or Akt1 knockout attenuated these effects. α2AR is a key regulator linking neuro‑immune crosstalk to type 2 airway inflammation. It promotes Tfh cell differentiation and allergic responses via AKT signaling. Targeting α2AR may represent a novel therapeutic strategy for asthma.

The lungs interface directly with the external environment, exposing them to airborne pathogens like endotoxins. We investigated whether the vagus nerve, which innervates the lungs-detects such pathogens. Using transcriptomics, tissue clearance imaging, electrophysiology, and cell-specific knockout models, we discovered that vagal sensory endings synapse with pulmonary neuroendocrine cells (PNECs). These nerve endings detect bacterial endotoxins primarily through the pain receptor TRPA1, not via Toll-like receptor 4 (TLR4). This detection triggers electrical excitation in vagal neurons and upregulates neuropeptide (e.g., αCGRP) production in the nodose ganglia. Released αCGRP then acts back on PNECs, stimulating their neuropeptide synthesis and proliferation. This creates a feed-forward loop that amplifies endotoxin-induced lung inflammation. Our findings reveal a critical neural circuit between the nodose ganglion and PNECs that regulates pulmonary inflammatory responses.

Abstract Mammalian tooth development progresses through two principal stages-crown formation and root development-orchestrated by intricate interactions between the oral epithelium and neural crest-derived mesenchyme. After crown formation, Hertwig’s epithelial root sheath (HERS) directs root development. In this phase, Gli1⁺ mesenchymal stem cells (MSCs) give rise to dental pulp, dentin, cementum, and the periodontal ligament (PDL). The root anchors the tooth to the alveolar bone via PDL fibers, forming a dynamic occlusal buffer that mediates mechanosensation and nutrient supply. Although previous work has shown that macrophages are abundant in the dental pulp and follicle, the functional importance of macrophages in tooth development has not been well characterized. Here, we investigated the spatiotemporal dynamics of macrophage populations (identified by CD68, F4/80, CD206, and other markers) in molars and surrounding tissues during postnatal root development in mice. Importantly, Macrophage depletion via clodronate liposomes resulted in shortened root, impaired PDL elongation and retarded alveolar bone shooting surrounding the root. Gli1⁺ MSCs exhibited increased proliferation but impaired osteo/odontogenic differentiation upon macrophage depletion. Single-cell RNA sequencing and in vitro co-culture experiments support a model in which macrophage-derived TGF-β acts on mesenchymal TGF-β receptors to direct MSC fate and thereby regulate root morphogenesis. Collectively, these findings establish macrophages as critical niche components that orchestrate tooth root development through immune–mesenchymal crosstalk.

Severe respiratory viral infections lead to extensive damage to the alveolar epithelium and also induce a robust immune response. How the immune microenvironment interacts with lung stem/progenitor cells and impacts alveolar regeneration is poorly understood. Here, we found that dysplastic KRT5+ basal-like cells, which emerge after severe viral infections, contribute to the recruitment and sequestration of CD4+ effector and CD8+ T cells in the lung after viral clearance in a CXCR3- and integrin α4β7-dependent manner. Persistent CD4+ effector and CD8+ T cells impair alveolar regeneration mediated via airway secretory cells by secreting IFNγ, thereby inhibiting lung functional repair. Importantly, anti-IFNγ treatment improves alveolar regeneration and lung function in vivo. Overall, our study reveals the pathogenetic role of dysplastic KRT5+ cells in alveolar regeneration, serving as a niche for tissue-resident lymphocytes that specifically inhibit alveolar regeneration. Additionally, our findings provide a potential therapeutic strategy to improve alveolar regeneration after viral pneumonia.

Resistance to chemotherapeutic agents is a critical challenge for the clinical management of ovarian cancer. While curcumin has been reported to possess anti-cancer properties, how it exerts its anti-neoplastic effect on ovarian cancer cells remains to be explored. We here characterized the fate of human ovarian cancer cell lines HO8910 and OVCAR3 treated with curcumin. Cell proliferation, cell death, mitochondrial function, oxidative damage and tumor formation in nude mice were examined. Significant inhibition of proliferation and induction of apoptosis were observed in ovarian cells treated with curcumin. The cancer cells exhibit cell cycle arrest at G2/M phase, mitochondrial accumulation, mitochondrial oxidative stress and high level of DNA damage after curcumin treatment. This effect of curcumin is independent of the BRCA mutation status. Curcumin-induced proliferation inhibition and apoptosis were effectively attenuated by the application of antioxidant N-acetylcysteine (NAC), suggesting that curcumin exerts its anti-cancer effect by inflicting oxidative stress. Curcumin applied at 200 mg/kg intraperitoneal infusion daily also inhibited the growth, oxidative damage, and mitochondrial accumulation of tumor xenografts in vivo. Together, the results indicate that curcumin can exert its anti-tumor effect via inducing mitochondrial dysfunction-associated oxidative DNA damage and can be potentially used in combination with other DNA repair-interfering therapeutics, such as PARP inhibitor, in the treatment of ovarian cancer.

The lungs are organs exposed to the external environment, and the air we inhale contains various pathogens, such as endotoxins. The vagus nerve, which innervates the lungs, may play a role in detecting pathogens that invade the lungs. Through transcriptome analysis, tissue clearance imaging, electrical excitability recording, and gene- and cell-specific knockout experiments, we found that vagus nerve endings innervate pulmonary neuroendocrine cells (PNECs). These nerve endings sense bacterial endotoxins via pain receptors (TRPA1) rather than toll-like receptors (TLR4), eliciting electrical excitation and enhancing the production of neuropeptides (αCGRP) in the nodose ganglia. In turn, αCGRP released by sensory neurons from the nodose ganglia promotes both neuropeptide production and the proliferation of PNECs, thereby amplifying endotoxin-induced lung inflammatory responses. This reveals that the neural circuits between the nodose ganglion and PNECs play a critical role in regulating lung inflammatory responses. ### Competing Interest Statement The authors have declared no competing interest.

BACKGROUND:Pulmonary neuroendocrine cells (PNECs) are adjacent to the vagus nerve, which innervates the lungs, and have been implicated in asthma pathogenesis. However, the neuroimmunomodulatory role of vagal-PNEC signaling in asthma remains poorly understood. METHODS:We developed an asthma model of C-fiber photoactivation and vagotomy to investigate the changes in PNECs. RNA sequencing (RNA-seq) was performed on flow cytometry-sorted PNECs to explore how vagus nerve C fibers affect the function of PNECs, with further validation in an in vitro cell model. Single-nucleus RNA sequencing (snRNA-seq) was conducted on airway samples of patients before and after bronchial thermoplasty (BT) treatment, and the changes of neural signals in different airway cell types and their crosstalk with PNEC after BT were analyzed in depth. RESULTS:Vagotomy reduced photoactivated TRPA1-mediated PNEC activation and allergic inflammation, inhibited the number and function of PNEC, and attenuated PNEC-mediated asthma response. PNEC RNA-seq results showed that photoactivation of TRPA1 in lung could promote the migration, aggregation, and synaptic transmission of PNECs and increase the synthesis and secretion of neuropeptides, which could also be activated by α7 nAChR of PNECs. BT therapy significantly reduced or interrupted NRG1-ERBB signaling between PNECs and other cells by interfering with PNEC secretion, synapse formation, and signaling, thereby alleviating the condition of asthma patients. CONCLUSIONS:We found that the vagal TRPA1-PNEC axis contributes to asthma severity. BT can disrupt this pathway through NRG1-ERBB signaling between PNECs and other cells to attenuate the inflammatory response in asthma.

Mesenchymal stem/stromal cells (MSCs) are integral components of the tumor microenvironment and critical for the colonization of disseminated cancer cells; specifically, stem cell antigen (Sca-1) is recognized as a surface marker of MSCs. In this study, we found that MSCs highly expressing Sca-1 are positively associated with lung metastasis. MSCs derived from the lungs of mice bearing metastasized breast tumors (LMSCs) exhibited higher level of Sca-1 compared to those with adenoma. When co-injected with 4T1 cells intravenously, Sca-1high LMSCs resulted in more tumor nodules in lung tissue than Sca-1low LMSCs. Furthermore, Sca-1high LMSCs expressed higher levels of CCL2, CCL7, and CXCL1 than Sca-1low LMSCs. Sca-1high LMSCs can directly recruit 4T1 cells through producing CXCL1. Additionally, Sca-1high LMSCs are highly potent in recruiting immune cells of the myeloid lineage (neutrophils and macrophages) to the lungs. Inhibition of macrophage chemotaxis by Bindarit, an inhibitor of CCL2/7/8 transcription, decreased the lung tumor burden induced by Sca-1high MSCs. Using Ccr5-/- mice, it was further confirmed that Sca-1high LMSCs promote tumorigenesis by recruiting macrophages, further supporting that the increased recruitment of macrophages mediates the pro-metastasis effect of Sca-1high LMSCs. Collectively, this study demonstrated that Sca-1high LMSCs and their effectors could be targeted to inhibit breast cancer metastasis to the lung.

Chronic stress adversely affects intestinal health, but the specific neural pathways linking the brain to intestinal tissue are not fully understood. Here, we show that chronic stress-induced activation of the central amygdala-dorsal motor nucleus of the vagus (CeA-DMV) pathway accelerates premature aging and impairs the stemness of intestinal stem cells (ISCs). This pathway influences ISC function independently of the microbiota, the hypothalamic-pituitary-adrenal (HPA) axis, the immune response, and the sympathetic nervous system (SNS). Under chronic stress, DMV-mediated vagal activation prompts cholinergic enteric neurons to release acetylcholine (ACh), which engages ISCs via the M3 muscarinic acetylcholine receptor (CHRM3). This interaction activates the p38 mitogen-activated protein kinase (MAPK) pathway, triggering growth arrest and mitochondrial fragmentation, thereby accelerating an aging-like decline in ISCs. Together, our findings provide insights into an alternative neural mechanism that links stress to intestinal dysfunction. Strategies targeting the DMV-associated vagal pathway represent potential therapeutic approaches for stress-induced intestinal diseases.

BACKGROUND:The chromatin status fluctuates with effector and memory group 2 innate lymphoid cell (ILC2) responses. How this intricate coordination affects allergic lung inflammation remains unclear. OBJECTIVE:We examined how the chromatin remodeler brahma-related gene 1 (Brg1) regulates ILC2s in allergic lung inflammation. METHODS:Acute lung allergic inflammation was induced with papain in wild-type, Il5Cre/+Smarca4flox/flox (Smarca4f/f), Il5Cre/+Hif1af/f, and Il5Cre/+Ldhaf/f mice. Secondary lung inflammation was induced with low-dose IL-33 in papain-primed Il5Cre/+Smarca4f/f mice. ATAC-Seq, RNA sequencing, and Brg1 CUT&Tag analyses were performed on naive ILC2s, effector ILC2s (ILC2eff), memory ILC2s (ILC2mem), IL-33-challenged Brg1-deficient ILC2s, Brg1-deficient ILC2mem, and human ILC2s treated with or without the Brg1 inhibitor Compound 14. ILC2 metabolism was analyzed by 13C glucose isotype tracing and metabolic flux, Seahorse, and SCENITH assays. Compound 14 was used to treat mouse and humanized mouse models of allergic lung inflammation. RESULTS:Brg1 expression was upregulated in asthma patients' ILC2s and was induced by IL-33. Brg1 promoted IL-5+ and IL-13+ ILC2 expansion and exacerbated both acute and secondary lung inflammation. Brg1 imprinted the chromatin landscape favoring aerobic glycolysis, the metabolic process reinforced in ILC2eff and ILC2mem. Brg1-augmented Hif1a enhancer accessibility was a sustained epigenetic signature in ILC2mem inherited from ILC2eff, and Hif1α enhanced ILC2eff and ILC2mem responses. Pharmacologic inhibition of Brg1, rather than dexamethasone treatment, in acute phase alleviated secondary lung inflammation. CONCLUSION:Brg1 promotes the expansion of pathogenic ILC2eff and ILC2mem and exacerbates allergic lung inflammation. Mechanistically, Brg1 increases the chromatin accessibility and transcription of Hif1a and Ldha, key factors reinforcing ILC2 glycolysis metabolism.

Mesenchymal stem/stromal cells (MSCs) have shown significant therapeutic effects in a range of autoimmune and hyperinflammatory diseases through their strong immunomodulatory properties, both in animal models and clinical settings. Exposure to inflammatory cytokines is crucial for MSCs to acquire immunoregulatory functions; however, the detailed mechanisms underlying this process remain largely unexplored. MSCs with pharmacological inhibition or genetic knockout of poly ADP-ribose polymerase1 (PARP1) were treated with the inflammatory factors IFNγ and TNFα for 24 h. The mRNA and protein expression of chemokines and immunosuppressive molecules were detected by qRT-PCR and Western blotting, respectively. The therapeutic efficacy of MSCs was evaluated using a mouse concanavalin A-induced acute liver injury model and a dextran sulfate sodium-induced inflammatory bowel disease model. The phosphorylation of signal transducer and activator of transcription 1 (STAT1) was analyzed in activated MSCs, and STAT1 inhibition through either a STAT1 inhibitor or STAT1 knockout was employed to confirm the role of STAT1 in enhancing the immunoregulatory function of MSCs during PARP inhibition. PARP inhibition or genetic knockout of PARP1 further enhanced the immunoregulatory function of MSCs elicited by inflammatory cytokines IFNγ and TNFα, as evidenced by the upregulation of genes associated with immunoregulation in MSCs, augmentation of immunosuppressive functions of MSCs on T cells, and increased therapeutic effects of MSCs in mouse models of autoimmune and hyperinflammatory diseases. PARP inhibition was further shown to enhance the expression of immunosuppressive factors in primed MSCs through increased phosphorylation at the tyrosine 701 site on STAT1. Our study indicates that like its pro-inflammatory role in macrophages, PARP also functions to undermine the immunosuppressive effects of MSCs, and PARP inhibition represents a strategy to further unleash the immunoregulatory power of MSCs.

The vagus nerve circuit, operating through the alpha-7 nicotinic acetylcholine receptor (alpha 7 nAChR), regulates the inflammatory response by influencing immune cells. However, the role of vagal-alpha 7 nAChR signaling in influenza virus infection is unclear. In particular, does vagal-alpha 7 nAChR signaling impact the infection of alveolar epithelial cells (AECs), the primary target cells of influenza virus? Here, we demonstrated a distinct role of alpha 7 nAChR in type II AECs compared to its role in immune cells during influenza infection. We found that deletion of Chrna7 (encoding gene of alpha 7 nAChR) in type II AECs or disruption of vagal circuits reduced lung influenza infection and protected mice from influenza-induced lung injury. We further unveiled that activation of alpha 7 nAChR enhanced influenza infection through PTP1B-NEDD4L-ASK1-p38MAPK pathway. Mechanistically, activation of alpha 7 nAChR signaling decreased p38MAPK phosphorylation during infection, facilitating the nuclear export of influenza viral ribonucleoproteins and thereby promoting infection. Taken together, our findings reveal a mechanism mediated by vagal-alpha 7 nAChR signaling that promotes influenza viral infection and exacerbates disease severity. Targeting vagal-alpha 7 nAChR signaling may offer novel strategies for combating influenza virus infections.

Neuroimmune recognition and regulation in the respiratory system is a complex and highly coordinated process involving interactions between the nervous and immune systems to detect and respond to pathogens, pollutants and other potential hazards in the respiratory tract. This interaction helps maintain the health and integrity of the respiratory system. Therefore, understanding the complex interactions between the respiratory nervous system and immune system is critical to maintaining lung health and developing treatments for respiratory diseases. In this review, we summarise the projection distribution of different types of neurons (trigeminal nerve, glossopharyngeal nerve, vagus nerve, spinal dorsal root nerve, sympathetic nerve) in the respiratory tract. We also introduce several types of cells in the respiratory epithelium that closely interact with nerves (pulmonary neuroendocrine cells, brush cells, solitary chemosensory cells and tastebuds). These cells are primarily located at key positions in the respiratory tract, where nerves project to them, forming neuroepithelial recognition units, thus enhancing the ability of neural recognition. Furthermore, we summarise the roles played by these different neurons in sensing or responding to specific pathogens (influenza, severe acute respiratory syndrome coronavirus 2, respiratory syncytial virus, human metapneumovirus, herpes viruses, Sendai parainfluenza virus, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus, amoebae), allergens, atmospheric pollutants (smoking, exhaust pollution), and their potential roles in regulating interactions among different pathogens. We also summarise the prospects of bioelectronic medicine as a third therapeutic approach following drugs and surgery, as well as the potential mechanisms of meditation breathing as an adjunct therapy.

Asthma exacerbations caused by respiratory viral infections are a serious global health problem. Impaired antiviral immunity is thought to contribute to the pathogenesis, but the underlying mechanisms remain understudied. Here using mouse models we find that Cullin5 (CUL5), a key component of Cullin-RING E3 ubiquitin ligase 5, is upregulated and associated with increased neutrophil count and influenza-induced exacerbations of house dust mite-induced asthma. By contrast, CUL5 deficiency mitigates neutrophilic lung inflammation and asthma exacerbations by augmenting IFN-β production. Mechanistically, following thymic stromal lymphopoietin stimulation, CUL5 interacts with O-GlcNAc transferase (OGT) and induces Lys48-linked polyubiquitination of OGT, blocking the effect of OGT on mitochondrial antiviral-signaling protein O-GlcNAcylation and RIG-I signaling activation. Our results thus suggest that, in mouse models, pre-existing allergic injury induces CUL5 expression, impairing antiviral immunity and promoting neutrophilic inflammation for asthma exacerbations. Targeting of the CUL5/IFN-β signaling axis may thereby serve as a possible therapy for treating asthma exacerbations.

Systemic sclerosis (SSc) is a challenging autoimmune disease characterized by progressive fibrosis affecting the skin and internal organs. Despite the known infiltration of macrophages and neutrophils, their precise contributions to SSc pathogenesis remain elusive. In this study, we elucidated that CD206hiMHCIIlo M2-like macrophages constitute the predominant pathogenic immune cell population in the fibrotic skin of a bleomycin (BLM)-induced SSc mouse model. These cells emerged as pivotal contributors to the profibrotic response by orchestrating the production of TGF-β1 through a MerTK signaling-dependent manner. Notably, we observed that neutrophil infiltration was a prerequisite for the accumulation of M2-like macrophages. Strategies such as neutrophil depletion or inhibition of CXCR1/2 were proven effective in reducing M2-like macrophages, subsequently mitigating SSc progression. Detailed investigations revealed that in fibrotic skin, neutrophil-released neutrophil extracellular traps (NETs) were responsible for the differentiation of M2-like macrophages. Our findings illuminate the significant involvement of the neutrophil-macrophage-fibrosis axis in SSc pathogenesis, offering critical information for the development of potential therapeutic strategies.

Dear Editor , Coronavirus disease 2019 ( COVID-19) , caused by severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2) infection, has led to > 6 million deaths and posed a huge threat to the global economy and public health. SARS-CoV-2 enters lung epithelial cells depending on the binding between SARS-CoV-2 S pro-tein and the host receptor angiotensin-converting enzyme 2 ( ACE2) .