Acta Pharmacologica Sinica最新文献

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is characterized by limited treatment options and a therapeutic ceiling. Failure to resolve inflammation is the key driver of disease progression. Formyl peptide receptor 2 (FPR2/ALX), a pivotal mediator of inflammation resolution, has emerged as a promising therapeutic target. In this study, we investigated the expression patterns of FPR2 and clinical relevance in myeloid and lymphoid cells of active IBD patients. By analyzing transcriptomic and single-cell RNA-sequencing data from the GEO database, we revealed aberrant expression of FPR2 and its associated genes in colonic mucosa of IBD patients. We found that FPR2/ALX was highly expressed in the colonic mucosa of UC and CD patients compared to non-IBD controls, strongly correlating with alterations in the MAPK pathway and myeloid cell composition. Notably, high mucosal FPR2/ALX levels were associated with poor response to anti-tumor necrosis factor-α (TNF-α) agent infliximab, and were predictive of disease status (AUC = 0.9143). To assess therapeutic potential, we established a dextran sulfate sodium (DSS)-induced colitis model in wild-type and Fpr2-silenced mice. The mice were orally treated with FPR2/ALX modulators Quin-C1 (QC1) and Quin-C7 (QC7) for 7 days. We showed that oral administration of QC1 or QC7 significantly reduced disease active index (DAI) in wild-type mice, whereas the therapeutic effects were markedly impaired in Fpr2-silenced mice. We conclude that FPR2/ALX may serve as a potential biomarker and therapeutic target for IBD.

Synthetic cannabinoids (SC) target the human cannabinoid receptor 1 (hCB₁) and are extensively metabolized, but the metabolite activity on the hCB₁ receptor after a SC intake is largely unknown. In this study we compared the in vitro hCB₁ receptor activity of 26 metabolites of the synthetic cannabinoid receptor agonists (SCRA) JWH-018, AM-2201, THJ-018 and THJ-2201 as a model system for SC metabolite activity to elucidate their structure-activity relationships. The efficacy and potency of metabolites were assessed using an AequoScreen hCB₁ receptor assay in triplicates and 7-8 concentration points (20 µg/mL-9.5 ng/mL) were used to construct dose-response curves and to determine EC₅₀ and E_max. In silico docking and molecular dynamics were performed using a model of the active form of the hCB₁ receptor with all the metabolites. Final poses were simulated to assess stability under physiological conditions. We showed that carboxylic acid metabolites and 2-hydroxyindole biotransformational products were inactive, while 5-hydroxypentyl SCRA metabolites decreased efficacy to <70%, qualifying them as partial agonists. Eighteen metabolites retained >70% efficacy of their parent compound. Metabolite potencies ranged from 13-3500 nM where the most potent were the 4-hydroxypentyl derivatives of THJ-2201 and THJ-018 and the 4-hydroxyindole derivatives of AM-2201 and JWH-018, also known to be prevalent in vivo metabolites. The efficacy data from in silico experiments were correlated with the in vitro results demonstrating a linear trend (R² = 0.9457), significant (P < 0.0001) at the 95% confident interval between the binding energies and efficacies of the compounds investigated. In silico analysis with docking and molecular dynamics simulations showed that active metabolites maintained a minimum of six amino acid interactions involving all substructures. The in silico molecular dynamics simulations revealed that the efficacy and potency seemed to be driven by a complex network of hydrophobic weak amino acid-ligand interactions. Most prevalent were CH-π interactions and π-π stackings. This study demonstrates the clear structure-activity relationships well correlated to the molecular dynamics simulations, suggesting that metabolites, especially the 4-hydroxy pentyl metabolites, may contribute to the overall effect of SCs in vivo.

Amyloid-beta (Aβ) aggregation is the key component of neuritic plaques that drives Alzheimer's disease (AD) progression and cognitive decline. Although synaptic dysfunction strongly correlates with cognitive impairment, its underlying mechanisms remain unclear. Recently, the kynurenine pathway (KP) of tryptophan metabolism has emerged as a key contributor to AD pathology, and xanthurenic acid (XA), a naturally occurring end-product of the KP, has been implicated in neuroprotection. In this study, we investigated the neuroprotective effects of intranasally administered XA in an Aβ-induced AD mouse model. AD-like pathology was induced in mice by intracerebroventricular injection of Aβ_1-42. The mice received daily intranasal instillation of XA (0.5 μg/5 μL per nostril) for 6 weeks. After XA treatment was completed, the cognitive performance was assessed in behavioral tests, then the mice were euthanized, and the brain were collected for molecular and biochemical analyses. We showed that XA treatment significantly improved the cognitive function of AD mice, and reduced AD-related pathological markers such as APP, Aβ and BACE-1 in the cortex, hippocampus and olfactory bulb. XA treatment also attenuated Aβ-induced oxidative stress through upregulation of the Nrf2/HO-1/SOD1 and key enzymatic antioxidants (GSH, GST, CAT, SOD), while concurrently reducing lipid peroxidation. Furthermore, XA treatment preserved synaptic integrity, evidenced by restoring both pre- and postsynaptic markers (SNAP-25, SYP, SNAP-23, PSD-95) and enhancing signaling via the cAMP-PKA-CREB pathway. Notably, XA differentially modulated metabotropic glutamate receptors, decreasing mGluR2 and increasing mGluR3 expression. In vitro experiments were conducted in APPswe/ind-transfected SH-SY5Y neuroblastoma cells. XA (3-100 µM) dose-dependently improved the cell viability while reducing cytotoxicity and apoptosis. Overall, these results demonstrate that XA confers multifaceted neuroprotection by modulating Aβ pathology, oxidative stress, synaptic function, and glutamatergic signaling, suggesting its potential as a novel therapeutic strategy to mitigate cognitive decline and pathological progression in AD.

Selective serotonin reuptake inhibitors (SSRIs) are characterized by delayed therapeutic onset largely due to their reliance on the desensitization of 5-HT_1A autoreceptors (5-HT_1AR_autos) within the dorsal raphe nucleus (DRN). It has been shown that dissociation of serotonin transporter (SERT) and neuronal nitric oxide synthase (nNOS) interaction selectively modulates 5-HT_1AR_autos, thereby facilitating fast-onset antidepressant responses. Targeting the atypical disk large/ZO-1 (PDZ) domain has been implicated in the SERT-nNOS interaction. In this study, we established a drug screening system based on mBRET combined with biological tests to find SERT-nNOS interaction blockers (SNIBs). During screening the compound libraries, 9 top candidates were found to be capable of binding to the PDZ domain of nNOS. We then identified esflurbiprofen as a promising fast-onset antidepressant candidate. Pharmacodynamic studies revealed that esflurbiprofen effectively penetrated the DRN following systemic administration. Esflurbiprofen (10, 20, 40 mg/kg, i.p., once every 4 days) dose-dependently ameliorated depressive-like behaviors in mice subjected to chronic social defeat stress (CSDS) and chronic restraint stress (CRS). In rs-fMRI analysis, we found that esflurbiprofen enhanced the functional connectivity of emotion-related neural networks in CSDS mice. We further demonstrated that esflurbiprofen disrupted the SERT-nNOS complex in the DRN, augmented membrane-associated SERT, and reduced the concentration of 5-HT in the extracellular space of the DRN. This cascade subsequently enhanced serotonergic neuronal firing through the inhibition of negative feedback mediated by 5-HT_1AR_autos, culminating in an augmented release of 5-HT from serotonergic neurons projecting to the prefrontal cortex and hippocampus. These results highlight the potential of esflurbiprofen to induce rapid antidepressant effects by targeting the SERT-nNOS interaction within the DRN.

Recent evidence shows that fatty acid synthase (FASN), a key regulator of de novo lipogenesis (DNL), is a promising therapeutic target for metabolic dysfunction-associated steatotic liver disease (MASLD). FASN inhibitors are under advanced clinical trials. In this study, we evaluated the therapeutic efficacy of a novel FASN inhibitor 84-B10 for the treatment of MASLD. RNA-seq analysis showed that FASN was significantly upregulated in PA/OA-treated mouse primary hepatocytes. In silico molecular docking screening combined with biochemical assay, 84-B10 exhibited the strongest FASN-inhibiting effect. We demonstrated that 84-B10 directly bound to the MAT domain of FASN, inhibiting its enzymatic activity and promoting its ubiquitination and proteasomal degradation. In mouse primary hepatocytes, 84-B10 induced Lys48-linked ubiquitination of FASN by recruiting the E3 ligase tripartite motif-containing 28 (TRIM28), leading to FASN protein degradation. In PA/OA-treated mouse primary hepatocytes, 84-B10 (5, 10 μM) dose-dependently ameliorated lipid accumulation and mitochondrial dysfunction. In HFD-fed mice, administration of 84-B10 (5 mg/kg, i.g. every other day for 6 weeks) significantly alleviated metabolic alterations and hepatic lipid accumulation. Our results establish 84-B10 as a novel FASN inhibitor that activating the FASN-TRIM28 axis by binding to the MAT domain, facilitating the proteasomal degradation of FASN. With favorable safety, tolerability, and pharmacokinetic properties, 84-B10 holds promise as a therapeutic candidate for the prevention and treatment of MASLD.

Deletion of IG20 (also known as MADD), which can encode multiple isoforms, causes diabetes in mice by impairing glucose-stimulated insulin secretion. To evaluate the role of IG20 in mediating the therapeutic potential of glinide-class insulin secretagogues, we tested their effects in Ig20/Madd-knockout (KMA1ko) mice. Glucose tolerance tests revealed that repaglinide, mitiglinide, and nateglinide failed to lower blood glucose levels or enhance insulin secretion in KMA1ko mice, suggesting that IG20 deficiency significantly diminishes the therapeutic efficacy of glinides. The functional relevance of at least 6 IG20 isoforms remains to be defined. Interestingly, among the six IG20 splicing isoforms re-expressed in IG20-deficient Min6 cells, only KIAA0358 was capable of restoring glucose-stimulated insulin secretion. Notably, KIAA0358 re-expression also rescued repaglinide-induced insulin secretion in vivo. Further transmission electron microscopy and total internal reflection fluorescence microscopy analyses showed that KIAA0358 significantly promoted insulin granule transport and docking impaired by IG20 knockout. Furthermore, guanine nucleotide exchange assay and GST pull-down demonstrated that KIAA0358 functions as a Rab GEF to convert Rab3A and Rab27A from the GDP-bound to the active GTP-bound state, thereby restoring their interactions with the downstream effector proteins Rim2α and Slac-2a that were impaired by IG20 deficiency. Therefore, by regulating the activation states of Rab3A and Rab27A, KIAA0358 mediated the transport and docking of insulin granules to the plasma membrane. This study also highlights that the genes encoding non-drug target proteins can influence drug efficacy and provides a novel conceptual foundation for precision medicine strategies aimed at reducing drug resistance and enhancing the clinical efficacy of glinides.

Macrophage migration inhibitory factor (MIF) is a cytokine that possesses multiple enzymatic activities, such as keto-enol tautomerase and thiol-oxidoreductase. We previously found that lack of MIF tautomerase activity significantly alleviated high fat diet (HFD)-induced obesity in mice. In this study, we investigated the regulatory mechanisms of MIF tautomerase in obesity. HFD-induced obese mouse model was established. Adipogenic differentiation was induced in mouse preadipocyte cell line 3T3-L1 and mouse adipose-derived mesenchymal stem cells (ADSCs) in vitro. We showed that MIF tautomerase inhibitors ISO-1 or 4-IPP dose-dependently promoted lipid degradation and mitochondrial thermogenesis by enhancing basal oxygen consumption rate and proton leak, accompanied by increased expression of browning markers (UCP1, PGC-1α, DIO2, CD137) in 3T3-L1 cells under adipogenic induction conditions. In HFD-induced obese mice, administration of 4-IPP (5, 10 mg/kg, i.p.) every 2 days for 12 weeks significantly ameliorated HFD-induced obesity, improved insulin sensitivity, and enhanced energy expenditure. In white adipocytes, 4-IPP (1, 5, 10 μM) dose-dependently promoted CD137 expression, and restored CD137-mediated activation of the PI3K/AKT signaling to improve lipid metabolism. CD137 deficiency abrogated the browning effect of 4-IPP in white adipocytes in vitro. CD137^-/- mice exhibited increased susceptibility to HFD-induced obesity and almost abolished the anti-obesity effects of 4-IPP. Simulation of the protein interaction revealed a direct interaction between MIF and CD137: MIF competitively bound to CD137 on white adipocytes with the endogenous ligand of CD137, which was further confirmed by co-immunoprecipitation. Furthermore, 4-IPP and recombinant CD137 protein inhibited the tautomerase activity of MIF in vitro. In conclusion, MIF promotes obesity by binding CD137 through its tautomerase domain, suppressing CD137-mediated the activation of the PI3K/AKT signaling. MIF tautomerase inhibitors disrupt this interaction, restore CD137 function, and enhance adipocyte browning, offering a promising therapeutic strategy for obesity management.

Lysosomal dysfunction exacerbates cardiomyocyte damage in myocardial infarction (MI) by impairing cellular degradation. However, the precise molecular mechanisms driving this pathologic process remain unclear. Lysosomal transmembrane protein 175 (TMEM175) is critical for regulating lysosomal homeostasis. But its pathophysiological implications in post-infarction cardiac dysfunction are not fully understood. By using both gain and loss of function approaches in vivo and in vitro, we discovered that TMEM175 overexpression conferred cardioprotection in MI models. This was evidenced by reduced infarct size, collagen deposition, and myocardial injury, accompanied by restored lysosomal function characterized by increased biogenesis, normalized pH, enzyme activities, and autophagic flux. Conversely, TMEM175 knockdown exacerbated these pathologies. Under hypoxic stress, TMEM175 overexpression in neonatal mouse cardiomyocytes (NMCMs) improved cell viability and corrected lysosomal dysfunction, whereas its knockdown worsened the aforementioned effects. Mechanistically, the reduction of TMEM175 induced by MI increases mammalian target of rapamycin complex 1 (mTORC1) phosphorylation on lysosomal membranes and suppresses the nuclear translocation of transcription factor EB (TFEB), thereby impairing TFEB's transcriptional regulation of lysosome-associated genes. Meanwhile, TMEM175 restoration reversing this cascade, and restoring lysosomal function and autophagic flux.

Sepsis is a life-threatening condition driven by dysregulated immune responses to infection with excessive M1 macrophage polarization-driven cytokine storm which plays a key role in the early progression of sepsis. Targeting macrophage polarization represents a promising therapeutic strategy to improve sepsis outcomes. Conventional drug discovery is hampered by high costs, long timelines and low success rates, posing significant challenges to the identification of novel M1 polarization inhibitors. In this study we constructed a novel transformer-variational autoencoder (TVAE) that integrated complementary molecular fingerprints (extended-connectivity fingerprints, ECFP; molecular ACCess system keys, MACCS keys; 4-point pharmacophore fingerprints, 4-PP) into probabilistic latent distributions to screen for M1-polarization inhibitors. From 5516 natural products, TVAE combined with experimental validation identified ombuin as the top candidate. In vitro, ombuin (10 μM) potently suppressed LPS-induced M1 polarization and pro-inflammatory cytokine (IL-6, TNF-α) release. In cecal ligation and puncture (CLP)-induced mouse sepsis model, administration of ombuin (15, 45 mg/kg, i.p.) significantly improved survival and ameliorated systemic inflammation by modulating the balance of M1/M2 macrophage polarization. By performing LiP-MS assay, we demonstrated that ombuin bound to and activated aldehyde dehydrogenase 2 (ALDH2), thereby suppressing NF-κB p65 nuclear translocation, a key event underlying NF-κB-driven M1 macrophage polarization. Collectively, our AI-driven pipeline efficiently discovers immunomodulatory agents and positions ombuin as a promising lead for sepsis therapy.

Stroke survivors usually suffer from mood and emotional disturbances, especially depression. However, research on poststroke depression (PSD) is limited by the measurement of behavioral despair in animals. The tail suspension test (TST) is a classic method for assessing behavioral despair in mice based on an increased immobility time. Ischemic mice assessed using the classic TST instinctively struggled because of incoordination, which influenced the immobility time and caused misleading results. In this study, we modified the classic TST equipment by introducing a smooth and transparent plate inclined at 60^° to help the suspended mouse maintain its balance during testing, without an obvious reduction in the aversive stress occurring during suspension. Finally, we validated the modified TST using mouse models of chronic mild stress, middle cerebral artery occlusion and PSD. Thus, the modified TST is an efficient method for assessing behavioral despair in mice with impaired motor coordination, especially after stroke.