Acta Pharmacologica Sinica最新文献

The cGAS-STING cytosolic DNA-sensing pathway is a key mediator of the innate immune response and plays a crucial role in antitumor immunity. The expression of cGAS and STING is often suppressed in tumor cells, and reduced expression is associated with poor prognosis and inferior response to immunotherapy. In this study we systematically investigated the expression pattern of cGAS-STING pathway in tumors and its correlation with immunotherapy response. We showed that the expression of cGAS and STING was significantly decreased or undetectable in most breast cancer and murine tumor cell lines, while high cGAS and STING expression was associated with increased T cell infiltration, elevated PD-L1 and PD-1 levels, improved immunotherapy response and prolonged survival. In cGAS-STING-deficient MDA-MB-453 cells, DNMT inhibitor decitabine (DAC, 0.05-1 μM) dose-dependently restored the impaired pathway by reversing DNA methylation-mediated silencing. Furthermore, DAC combined with a chemotherapeutic agent cisplatin significantly enhanced the antitumor effect in MDA-MB-453 and MDA-MB-231 cells by activating the cGAS-STING pathway through cytoplasmic DNA accumulation. In addition, DNMT inhibition elevated intracellular dsRNA levels and activated the RIG-I/MDA5-MAVS pathway. These results suggest that DNMT inhibitors can epigenetically reprogram the cGAS-STING pathway, activate the RIG-I/MDA5-MAVS pathway, and in combination with chemotherapeutic agents, synergistically promote antitumor immunity. Together, this study identifies cGAS-STING as a potential predictor of immunotherapy response and highlights a novel therapeutic strategy for restoring innate immune function in cancer. Loss of cGAS-STING signaling in tumors impairs antitumor immunity and correlates with poor immunotherapy response. DNMT inhibition restores cGAS-STING pathway and concurrently activates the RIG-I/MDA5-MAVS signaling, synergistically enhancing immune infiltration and antitumor efficacy.

Acetaminophen (APAP)-induced liver injury (AILI) is a leading cause of acute liver failure, with limited preventive or therapeutic options. The role of betaine-homocysteine methyltransferase (BHMT), a key enzyme in the methionine cycle, remains unclear. We found that BHMT, primarily expressed in hepatocytes, showed reduced expression in the liver but elevated serum levels in the APAP-induced liver injury (AILI) mouse model. GalNAc-mediated targeted knockdown of Bhmt in hepatocytes aggravated AILI in mice. Through RNA-seq screening, we found that Bhmt deficiency dramatically suppressed stearoyl-coenzyme A desaturase 1 (SCD1) expression. Knockdown of Scd1 also exacerbated AILI. Mechanistically, Bhmt knockdown decreased the DNA methylation of BACH1 (BTB and CNC homology 1), a transcriptional factor, leading to upregulated BACH1 expression in primary mouse hepatocytes (PMHs) treated with APAP. BACH1 then bound to the enhancer region of Scd1, transcriptionally repressing SCD1. Lipidomic analysis revealed that Bhmt or Scd1 deficiency reduced levels of intracellular unsaturated fatty acids, particularly oleic acid (OA), whereas SCD1 overexpression increased OA levels and decreased lipid peroxides. OA administration alleviated AILI and mitigated the hepatotoxicity associated with Bhmt or Scd1 knockdown. Our findings indicate that BHMT mitigates AILI via the BACH1-SCD1-OA axis, suggesting that BHMT could serve as a preventive target for AILI, while increasing OA intake may offer dietary benefits for patients.

Mitochondrial DNA (mtDNA) damage and accumulation activate the cGAS-STING DNA-sensing pathway, which promotes immune clearance of tumor cells. Maintenance of the cytosolic level of mtDNA is key to sustain immune activation. T cell malignancies (T-CMs) are a general name of diseases with abnormal clonal proliferation of T lymphocytes at various stages. Immunotherapy of T-CMs is challenged by the lack of specific antigens to discriminate T-CMs from normal T cells. As intrinsic STING activation can promote the clearance of T-CMs by immune cells, we herein explored whether isoliensinine (IsoL), a natural compound from Nelumbinis Plumula could enhance NK clearance by mtDNA-mediated immune responses in tumor cells. To investigate whether IsoL modulated immune recognition and clearance of T-CMs, we pre-treated three T-CM cell lines (Jurkat, Molt4 and Hut102) with IsoL then co-cultured with NK-92MI cells. We showed that IsoL pre-treatment promoted cytosolic mtDNA accumulation by inducing ROS-dependent mitochondrial damage and inhibiting mitophagy via peroxiredoxin 1 (PRDX1), an antioxidant enzyme. Loss of PRDX1 in T-CMs also induced ROS-dependent mitochondrial DNA damage, and blocked mitophagy by preventing accumulation of mature PINK1, which was required to initiate mitophagy via recruiting Parkin to the damaged mitochondria. Remarkably, IsoL could induce expression of activating ligands in vitro, enhance NK cell infiltrations, and increase apoptosis of T-CMs. Moreover, we demonstrated that IsoL could sensitize T-CMs for NK clearance in vitro and in vivo. These results suggest that IsoL could be a potential therapeutic agent to enhance immune therapy of T-CMs.

N-methyl-D-aspartate receptors (NMDARs) are calcium-permeable ionotropic glutamate receptors broadly expressed throughout the central nervous system, where they play crucial roles in neuronal development and synaptic plasticity. Among the various subtypes, the GluN1/GluN3A receptor represents a unique glycine-gated NMDAR with notably low calcium permeability. Despite its distinctive properties, GluN1/GluN3A remains understudied, particularly with respect to pharmacological tools development. This scarcity poses challenges for deeper investigation into its physiological functions and therapeutic relevance. In this study, we employed a hybrid virtual screening (VS) pipeline that integrates ligand-based and structure-based approaches for the efficient and precise identification of small-molecule candidates targeting GluN1/GluN3A. A large compound library comprising 18 million molecules was screened using an AI-enhanced multi-stage method. The initial phase utilized shape similarity ranking via ROCS-BART, followed by refinement with a graph neural network (GNN)-based drug-target interaction model to enhance docking accuracy. Functional validation using calcium flux (FDSS/μCell) identified two compounds with IC₅₀ values below 10 μM. Of these, one candidate exhibited potent inhibitory activity with an IC₅₀ of 5.31 ± 1.65 μM, which was further confirmed through manual patch-clamp recordings. These findings highlight an AI-enhanced VS workflow that achieves both efficiency and precision, providing a promising framework for exploring elusive targets such as GluN1/GluN3A.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of nigral dopaminergic neurons and abnormal accumulation of α-synuclein. Our recent study has shown that α-synuclein induces cellular senescence prior to the loss of dopaminergic neurons and the onset of motor dysfunction. Microglia are known to contribute to dopaminergic neurodegeneration, primarily through NLRP3-mediated neuroinflammatory mechanism or by facilitating the propagation of α-synuclein. In this study, we identified the cell type susceptible to α-synuclein-induced cellular senescence in the substantia nigra and investigated the specific role of microglia with a particular focus on the NLRP3 inflammasome. PD mouse model was established by bilateral microinjection of viaAAV2/9 vectors encoding human α-syn-A53T into the SNpc to overexpress human mutant α-synuclein-A53T. We showed that overexpression of α-synuclein-A53T (α-syn-A53T) for 1 week not only induced a pro-inflammatory phenotype in nigral microglia but also led to the acquisition of a senescent state in a subset of microglial cells. Depletion of microglia by administration of the CSF1R inhibitor PLX5622 (1200 ppm) in diet for 1 week significantly attenuated α-synuclein aggregation, iron dysregulation and cellular senescence in the substantia nigra of PD mouse model. Transcriptomic and immunostaining analyses revealed that α-syn-A53T promoted senescence in nigral dopaminergic neurons via the SATB1/DNA damage/p21 signaling pathway, evidenced by reduced SATB1 expression along with increased levels of γ-H2A.X and p21 in TH-positive dopaminergic neurons within the substantia nigra. Moreover, genetic knockout of NLRP3 effectively mitigated α-syn-A53T-induced cellular senescence in these neurons by suppressing the SATB1/DNA damage/p21 signaling pathway. These results highlight the critical role of microglia in promoting dopaminergic neuronal senescence and suggest that NLRP3 may serve as a promising therapeutic target for early intervention in PD to mitigate neuronal senescence and subsequent neurodegeneration.

Cancer stem cells (CSCs) play a key role in the progression of colorectal cancer (CRC). The high heterogeneity of CSCs has hindered the clinical application of CSC-targeting therapies. Tetracyclines are drugs with therapeutic potentials beyond their antibiotic activity. We previously demonstrated the efficacy of tigecycline, a third-generation tetracycline, against a model of colitis-associated colorectal cancer, primarily focusing on its immunomodulatory role with a preliminary assessment of its impact on stemness. In this study we characterize the effects of tigecycline on colon CSCs in vitro and in a CRC xenograft model, with special attention on the signaling pathways involved and the modulation of the gut microbiota. We generated secondary colonospheres from two colon tumor cell lines HCT116 and CMT93, and evaluated the effect of tigecycline on CSCs properties. We showed that tigecycline (25, 50 μM) effectively reduced colon CD133⁺CD44⁺LGR5⁺ALDH⁺ subpopulations and their viability, self-renewal and migratory capacity. Moreover, tigecycline treatment hindered epithelial-mesenchymal transition (EMT) process through targeting SNAI1 and β-catenin, resulting in an upregulation of epithelial markers (E-cadherin) and a downregulation of pluripotency and mesenchymal ones (Vimentin, N-cadherin, SOX2, NANOG, MIR155, MIR146). This effect was confirmed in two independent CRC-xenograft murine models in which tigecycline administration led to a reduction in tumor volume. Finally, CRC samples were taken from HCT116 xenograft model mice for analysis of CSCs-related signaling pathways and stools were collected for gut microbiome metagenomic analysis. We found that the antibiotic modulated gut dysbiosis by increasing the abundance of beneficial bacterial species such as Parabacteroides sp., which were involved in metabolic pathways that hindered SNAI1-Wnt-β-catenin signaling. These results reinforce the new role of tigecycline in the therapy of CRC and demonstrate for the first time the effect of tigecycline on colon CSCs and their malignancies.

The management of rheumatoid arthritis (RA) has advanced into the realm of targeted therapies; however, these therapies often lack tissue specificity and cause systemic adverse effects. Fibroblast-activating protein α (FAPα⁺) expressing fibroblast-like synoviocytes (FLSs) are critical pathogenic cell components in RA and are particularly abundant in inflamed joints, whereas they are minimal in other tissues. Consequently, FAPα⁺ FLSs are emerging as promising therapeutic targets for treating RA. However, strategies to specifically target FAPα⁺ FLSs in RA remain underdeveloped. To bridge this gap, we developed a novel compound, FAPI-Gly-Pro-MTX (FM), which integrates a FAPα⁺ tracer, FAPα inhibitor (FAPI), with the traditional drug methotrexate (MTX) via a glycine-proline dipeptide that can be cleaved by the dipeptidyl peptidase activity of FAPα. In an arthritis mouse model, FM selectively targeted FAPα⁺ FLSs in inflamed joints, facilitating the localized release of MTX and resulting in the significant alleviation of arthritis symptoms while minimizing systemic toxicity. Importantly, the presence of FAPI ensured that FM induced cell death specifically when FAPα⁺ FLSs were presented, thereby enhancing safety. Consequently, FM demonstrated considerable clinical potential as a safe and effective off-the-shelf therapeutic option for targeting FAPα⁺ FLSs in patients with RA. a FAPα⁺ FLSs are induced by various inflammatory cytokines in inflamed joints and aggravate inflammation and bone destruction; b FM selectively delivers MTX to FAPα⁺ FLSs in RA-inflamed joints and minimizes off-target effects; c Conventional MTX administration lacks cell specificity, leading to systemic adverse effects.

Chemoresistance is a major factor contributing to the poor prognosis of osteosarcoma. Increasing evidence underscores the pivotal role of enhanced tumor stemness in driving drug resistance. In this study we investigated the molecular mechanisms underlying the chemoresistance and stemness in osteosarcoma. Two cisplatin-resistant osteosarcoma cell line models (U2OS-DDPr and 143B-DDPr) were established by culturing parental U2OS and 143B cells with escalating cisplatin concentrations (250 ng/mL to 2.5 µg/mL) over a 6-month period. We found that the expression levels of suppressor of cytokine signaling 1 (SOCS1), an E3 ubiquitin ligase, were markedly downregulated in both chemo-resistant osteosarcoma cells and osteosarcoma tumor specimens, and the reduced expression in tumor specimens was correlated to poor prognosis in osteosarcoma patients. Silencing SOCS1 significantly reduced cisplatin sensitivity, enhanced spheroid formation capacity, and upregulated the expression of stem cell markers including SOX2, OCT4, and CD44. Conversely, restoring SOCS1 expression reversed these effects both in vitro and in vivo. Immunoprecipitation-mass spectrometry analysis revealed that SOCS1 bound to ACTN4 and suppressed its protein expression by promoting K63-linked ubiquitination, ultimately leading to proteasomal degradation. Specifically, the SH2 domain of SOCS1 interacted with the N-terminal region of ACTN4, with Lys66 of ACTN4 playing a critical role in facilitating this interaction and subsequent ubiquitination. In addition, the expression of ACTN4 was highly enriched in chemo-resistant tissues, and its overexpression was positively associated with advanced tumor staging. Importantly, ACTN4 functioned as an oncogene to promote cisplatin resistance and stemness in osteosarcoma. Furthermore, we found that wortmannin, an inhibitor of ACTN4, could markedly block the effect of SOCS1 silencing on osteosarcoma aggressiveness. In conclusion, SOCS1 deletion promotes stemness and chemoresistance in osteosarcoma by inhibiting ACTN4 ubiquitination and degradation, which offers promising therapeutic targets for potentiating chemosensitivity in osteosarcoma.

Reduced nicotinamide adenine dinucleotide phosphate (NADPH) is an important coenzyme involved in cellular biosynthetic and redox metabolism. It has been recognized for its role in regulating neuroinflammation through coordinating redox reactions. Whether there are new actions other than redox regulation remain unclear. In this study we investigated a novel mechanism by which NADPH regulated microglia-mediated neuroinflammation. We showed that NADPH application significantly alleviated NLRP3 inflammasome activation in microglia and exerted neuroprotective effects both in vitro and in vivo neuroinflammation models. With P2X7R knockdown microglial cells and P2X7R^cKO mice, we demonstrated that P2X7R was a crucial mediator of the anti-inflammatory effects for the supplemented NADPH. We conducted whole-cell recording from murine microglial cell line BV2 cells, and found that application of ATP (1 mM) elicited an inward current, which was reduced by co-application of P2X7R antagonist A-438079 (20 μM) or NADPH (1 mM). By performing a drug affinity responsive targets stability (DARTS) assay, we revealed that NADPH (not NADP⁺ or NADH), like the P2X7R agonist ATP, bound to the extracellular domain of P2X7R, leading to the suppression of ATP-induced P2X7R activation. Our research provides the first evidence of NADPH as an endogenous inhibitor of P2X7R in modulation of microglia-mediated neuroinflammation. This study expands the biological functions of NADPH and offers a novel target for NADPH-based therapies in neuroimmune-related diseases.