British Journal of Pharmacology最新文献

Background and purpose: Genetic ablation or inhibition of the cation channel TRPC6 is protective against renal, cardiac and intestinal fibrosis. However, TRPC6 expression is decreased in patients with liver diseases. Here, we explored the role of TRPC6 in liver fibrosis and the underlying mechanism.

Experimental approach: Bile duct ligation and thioacetamide gavage were used to model liver fibrosis in C57BL/6J mice. Western blotting, immunolabelling and qPCR were employed for protein and mRNA expression. Liver injury/fibrosis were assessed using serum alanine transaminase and aspartate transaminase assays, haematoxylin-eosin, Masson and Sirius red staining. Adenoviruses were used to overexpress TRPC6 and CREB1^Y134F. ChIP and dual-luciferase reporter assays were performed to test the direct inhibition of Acta2 transcription by CREB.

Key results: TRPC6 protein levels were decreased in fibrotic liver tissues from both patients and mice, with the decrease being more robust in fibrotic areas. In hepatic stellate cells (HSCs), TRPC6 ablation aggravated liver injury and fibrosis, which was alleviated by overexpressing TRPC6. In primary cultured HSCs, deletion of TRPC6 exacerbated self-activation of HSCs, which was reversed by restoration of TRPC6 expression. Mechanistically, TRPC6 suppressed HSC activation through CaMK4-mediated CREB phosphorylation. CREB directly interacted with the promoter region of Acta2 to inhibit its transcription. Expression of a constitutively active form of CREB1 (CREB1^Y134F) in HSCs attenuated BDL-induced liver injury/fibrosis in TRPC6 knockout mice.

Conclusion and implications: Deficiency of TRPC6 aggravates liver injury/fibrosis through augmentation of HSC activation. Increasing TRPC6 expression/function would be therapeutically beneficial for fibrotic liver diseases.

Background and purpose: Breast cancer is a leading threat to women's health, with approximately 70% of cases being estrogen receptor-positive. SGK3 is regulated by estrogen and is positively associated with estrogen receptor expression, although its molecular role remains unclear.

Experimental approach: Proteomics was used to identify SGK3's downstream targets. Tissue microarray immunofluorescence evaluated SGK3 and ZMIZ2 expression in ER+ breast cancer. Lentiviral-mediated knockdown and overexpression of SGK3 and/or ZMIZ2 assessed their effects on cell proliferation in vitro and in vivo. Chromatin immunoprecipitation (ChIP) analyzed p-STAT3 binding to the ZMIZ2 promoter, and Co-immunoprecipitation (Co-IP) examined ZMIZ2-β-catenin interaction.

Key results: SGK3 expression was elevated in breast tumour tissues correlating with reduced patient survival. Proteomic analysis identified ZMIZ2 as a downstream target of SGK3. Overexpression of SGK3 promoted the proliferation of estrogen receptor-positive breast cancer in MCF-7 and T47D cells. Inhibition had the opposite effects. ZMIZ2 overexpression rescued the proliferation deficit in SGK3 knockdown cells. ZMIZ2 was found to bind and stabilises β-catenin. Knockdown of SGK3 led to β-catenin degradation via polyubiquitination, a process reversed by ZMIZ2 overexpression. STAT3 was identified as a downstream effector of SGK3 and its knockdown reduced cytoplasmic and nuclear p-STAT3 and STAT3, and inhibited ZMIZ2 and β-catenin expression. Celastrol suppressed estrogen receptor-positive breast cancer cell proliferation by inhibiting the SGK3/STAT3/ZMIZ2/β-catenin pathway.

Conclusions and implications: SGK3 expression is associated with poorer survival rates, thus SGK3 is a potential therapeutic target. As celastrol can inhibit SGK3 expression it could be an effective therapeutic agent.

Background and purpose: Inflammatory bowel disease (IBD) patients display genetic polymorphisms in toll-like receptor 4 (TLR4) genes, contributing to dysregulate enteric nervous system (ENS) circuits with increased levels of 5-HT and alteration of the neuroimmune crosstalk. In this study, we investigated the impact of TLR4 signalling on mouse ENS dysfunction caused by dextran sulphate sodium (DSS)-induced ileitis.

Experimental approach: Male C57BL/6J (wild-type [WT]) and TLR4^-/- mice (10 ± 2 weeks old) received 2% DSS in drinking water for 5 days and then were switched to 3-day regular drinking water. Histological analysis and proinflammatory cytokine mRNA levels were assessed in ileal samples. Gut motility was evaluated by changes in transit of a fluorescent-labelled marker and isometric neuromuscular responses of ileal full-thickness segments to receptor and non-receptor-mediated stimuli. Alterations in ENS architecture were assessed by confocal immunohistochemistry in longitudinal muscle-myenteric plexus whole-mount preparations.

Key results: In WT mice, DSS treatment caused delayed gastrointestinal transit, ileal myenteric neurodegeneration, reactive gliosis and release of proinflammatory cytokines. Enhanced cholinergic and tachykinergic excitatory tone, increased inducible nitric oxide synthase (iNOS)-mediated relaxation, and changes in 5-HT_2A and 5-HT₃ receptor-mediated responses were observed during ileitis in WT mice. TLR4 deficiency reversed most of the functional and morphological abnormalities.

Conclusion and implications: Our results demonstrate that TLR4 activity influences the severity of ileitis, neuroglial plasticity, gut motility, and nitrergic and 5-HTergic neurotransmissions. The neuroimmune interaction between TLR4 and 5-HT observed in our study appears to be a potential pharmacological target to treat ENS dysfunction implicated in IBD onset/progression.

Background and purpose: Perivascular adipose tissues (PVATs) play a critical role in modulating vascular homeostasis and protecting against cardiovascular dysfunction-mediated blood pressure dysregulation. We demonstrated that the activating transcription factor-3 (Atf3) gene in the PVAT is crucial for improving vascular wall tension abnormalities; however, its protective mechanism remains unclear. Herein, we aim to determine whether ATF3 regulates PVAT-derived relaxing factor (PVDRF) biosynthesis and if its secretion contributes to vasorelaxation.

Experimental approach: This study employed an in vivo animal model using global Atf3-deficient mice, in vitro blood vessel myography, and biochemical analyses to evaluate ATF3-mediated PVDRF release and reactivity in the vasculature.

Key results: Wild-type (WT) mouse thoracic aortic PVAT extracts significantly induced resting tone dilation and attenuated vasoconstrictor-induced contractile responses compared to Atf3^-/- mice. Heat-stable PVAT extracts from WT mice caused sustained and reproducible vasodilation without tachyphylaxis in control aortic rings. Biochemical evaluation of PVDRF release revealed that Atf3^-/- mice had lower sphingosine-1-phosphate (S1P) and HDL cholesterol (HDL-C) levels than WT mice. Furthermore, PVAT extracts from WT mice induced long-lasting vasorelaxation, which was significantly inhibited by the S1P₃ receptor antagonist TY52156 and scavenger receptor class B type 1 receptor antagonist glyburide.

Conclusion and implications: ATF3 within the PVAT can modulate vascular function by strengthening sphingosine kinase 1 (sphk1)-S1P-S1P₃ receptor lipid signalling and stimulating S1P binding to HDL to form the vasodilator HDL-S1P. ATF3 is an essential modulator for maintaining the physiological function of PVAT, providing a novel target for treatment of obesity-related cardiovascular diseases.

Background and purpose: The use of 'bath salts' drug preparations has been associated with high rates of toxicity and death. Preparations often contain mixtures of drugs, including multiple synthetic cathinones or synthetic cathinones and caffeine. Little is known about the interactions of 'bath salts' constituents and adverse effects often reported by users.

Experimental approach: This study used adult male Sprague-Dawley rats to characterise the cardiovascular effects, locomotor effects and pharmacokinetics of methylone, methylenedioxypyrovalerone (MDPV) and caffeine, administered alone and as binary mixtures. Dose-addition analyses were used to determine the effect levels of a strictly additive interaction for dose pairs.

Key results: Methylone, MDPV and caffeine increased heart rate (HR) and locomotion, with methylone producing the largest increase in HR, MDPV producing the largest increase in locomotor activity and caffeine being the least effective in stimulating HR and locomotor activity. MDPV and caffeine increased mean arterial pressure (MAP), with caffeine being more effective than MDPV. The nature of the interactions between methylone and MDPV tended towards sub-additivity for all endpoints, whereas interactions between MDPV or methylone and caffeine tended to be additive or sub-additive for cardiovascular endpoints, and additive or supra-additive for increases in locomotion. No pharmacokinetic interactions were observed between individual constituents, but methylone appeared to display nonlinear pharmacokinetics at the largest dose evaluated.

Conclusion and implications: These findings demonstrate that 'bath salts' preparations can impact both cardiovascular and locomotor effects and suggest that interactions among constituent drugs could contribute to the 'bath salts' toxidrome reported by human users.

Drug discovery is a complicated process through which new therapeutics are identified to prevent and treat specific diseases. Identification of drug-target interactions (DTIs) stands as a pivotal aspect within the realm of drug discovery and development. The traditional process of drug discovery, especially identification of DTIs, is marked by its high costs of experimental assays and low success rates. Computational methods have emerged as indispensable tools, especially those employing artificial intelligence (AI) methods, which could streamline the process, thereby reducing costs and time consumption and potentially increasing success rates. In this review, we focus on the application of AI techniques in DTI prediction. Specifically, we commence with a comprehensive overview of drug discovery and development, along with systematic prediction and validation of DTIs. We proceed to highlight the prominent databases and toolkits used in developing AI methods for DTI prediction, as well as with methodologies for evaluating their efficacy. We further extend the exploration into three primary types of state-of-the-art AI methods used in DTI prediction, including classical machine learning, deep learning and network-based methods. Finally, we summarize the key findings and outline the current challenges and future directions that AI methods face in scientific drug discovery and development.

Background and purpose: Spinal cord injury (SCI) is a neurological condition that affects motor and sensory functions below the injury site. The consequences of SCI are devastating for the patients, and although significant efforts have been done in the last years, there is no effective therapy. Baclofen has emerged in the last few years as an interesting drug in the SCI field. Already used in the SCI clinical setting to control spasticity, baclofen has shown important impact on SCI recovery in animal models, such as lampreys and mice.

Experimental approach and key results: Herein, we proposed to go deeper into baclofen's mechanism of action and to study its role on the modulation of the immune response after SCI, a major process associated with the severeness of the lesion. Using a SCI compression mice model, we confirmed that baclofen leads to higher locomotor performance, but only at 1 mg·kg^-1 and not in higher concentrations, as 5 mg·kg^-1. Moreover, we found that baclofen at 1 mg·kg^-1 can strongly modulate the immune response after SCI at local, systemic and peripheric levels. This is interesting and intriguingly at the same time, since now, additional studies should be performed to understand if the modulation of the immune response is the responsible for the locomotor outcomes observed on Baclofen treated animals.

Conclusion and implications: Our findings showed, for the first time, that baclofen can modulate the immune response after SCI, becoming a relevant drug in the field of the immunomodulators.