British Journal of Pharmacology最新文献

Background and purpose: The leukocyte-mediated innate inflammatory response is crucial for clearing ischaemic debris during myocardial infarction (MI). If unresolved, it leads to chronic inflammation and heart failure. While macrophages produce specialised pro-resolving mediators (SPMs) like maresin 1, the therapeutic potential of exogenous maresin 1 in cardiac repair remains unclear.

Experimental approach: Male C57BL/6J mice (8-12 weeks) subjected coronary artery ligation to induce MI. Mice received either low-dose (LD; 0.4 μg kg^-1) or high-dose (HD; 4 μg kg^-1) maresin 1 subcutaneously 3 h post-MI, continued through day 1 or day 5. Saline-injected mice served as MI controls, while non-infarcted mice were used as naïve controls.

Key results: LD-maresin 1 enhanced neutrophil clearance but did not improve cardiac function. However, HD-maresin 1 significantly improved cardiac performance, evidenced by higher fractional shortening and global longitudinal strain, and reducing LV and lung mass-to-body weight ratios. In infarcted myocardium, HD-maresin 1 up-regulated FPR2 receptor expression and increased levels of SPMs (RvD5, PD-1, maresin 1). Flow cytometry showed accelerated neutrophil clearance from the LV and spleen. Moreover, HD-maresin 1 also promoted a reparative macrophage phenotype, with expansion of Ly6C^lo cells and up-regulation of Mrc1 and Arg1. Furthermore, kidney immunohistochemistry showed reduced NGAL and increased nephrin expression, indicating attenuation of cardiorenal inflammation.

Conclusions and implications: High-dose maresin 1 activates FPR2 signalling and enhances the resolution of inflammation by modulating leukocyte dynamics and macrophage phenotype. Improving cardiac function and attenuating cardiorenal inflammation, highlighting the therapeutic potential of maresin 1 in cardiac healing and acute heart failure.

Background and purpose: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease, mainly affecting adult males. Although it exhibits a primarily fibrosing imprint, it serves as a model for understanding inflammation-driven interstitial lung diseases that can evolve into PF. We analysed the interplay between inflammation and fibrosis, in relation to sex in a mouse model of PF.

Experimental approach: Adult C57BL/6 mice of both sexes were treated with subcutaneous bleomycin injection (3 times a week for 1-4 weeks). We used RT-PCR, western blotting and immunohistochemistry, along with ELISA, flow cytometry and mass spectrometry (UPLC-MS/MS) to analyse our results.

Key results: Male mice developed more severe fibrosis, with higher levels of collagen, and enhanced pulmonary epithelial-mesenchymal transition, compared with females. Males also showed early cell infiltration (neutrophils and macrophages) during the initial stages, followed by loss of lung architecture and an exacerbated development of fibrosis. In contrast, females exhibited physiological resolution of lung inflammation after 2 weeks of bleomycin treatment. In males, PF was associated with increased pro-inflammatory/fibrotic mediators (TGF-β and IL-1β) and decreased anti-inflammatory/anti-fibrotic factors (IFN-γ, miRNA-214-3p, miRNA-96-5p and PGE₂), particularly in the early phase of fibrosis. Pre-treatment with pirfenidone reversed fibrosis features more effectively in males, impacting anti-fibrotic miRNA-214-3p and miRNA-96-5p.

Conclusions and implications: Our data suggest that while inflammation occurs in both males and females during the early stages of PF induction, exacerbated fibrosis is observed only in males. Additionally, pirfenidone demonstrated greater activity in male mice, highlighting the need to consider potential sex-specific pharmacotherapy.

Background and purpose: LCZ696 (sacubitril/valsartan) can attenuate early cardiac remodelling of heart failure (HF), although it is less effective in severe remodelling. Surgical ventricular reconstruction (SVR) is used to treat refractory HF with large ventricular aneurysms (LVA), but residual remodelling limits the long-term survival. It is unknown whether LCZ696 can mitigate residual remodelling.

Experimental approach: Male C57BL/6 mice were subjected to myocardial infarction (MI) or sham surgery. Four weeks later, MI mice with LVA underwent SVR or a second open-chest operation, followed by randomisation to LCZ696 or vehicle. Echocardiography, histological analysis, and immunofluorescence staining were used to evaluate heart function, cardiac remodelling, and myocardial proliferation. Molecular docking, RNA pull-down, and RNA protein immunoprecipitation were used to explore downstream mechanisms. Non-targeted metabolomics and bioinformatics analysis were used to characterise metabolic changes.

Key results: LCZ696 significantly attenuated residual remodelling and further enhanced cardiomyocyte proliferation in SVR mice, but not MI mice, as evidenced by positive staining of Ki-67, phospho-histone H3, and Aurora B in the plication zone. LCZ696 increased circMap4k2 expression in SVR hearts. Silencing of circMap4k2 inhibited the efficacy of LCZ696 on improving SVR residual remodelling and cardiac proliferation, whereas overexpression of circMap4k2 promoted it. Mechanistically, circMap4k2 bound to LIN28 homologue A (LIN28A), elevating pyruvate dehydrogenase kinase 1 (PDK1) expression, thereby promoting glycolysis and reducing residual remodelling. LCZ696 reprogrammes cardiac metabolism after SVR, with 195 metabolites up-regulated and 99 down-regulated.

Conclusion and implications: LCZ696 induces glycolysis, promotes myocardial repair, and alleviates residual remodelling of SVR by targeting the circMap4k2/LIN28A/PDK1 pathway.

Chronic visceral pain imposes a major clinical challenge in gastroenterology and beyond, profoundly impacting patients' quality of life. However, limited understanding of its complex, multifaceted pathophysiology, encompassing both peripheral and central mechanisms, continues to impede the development of effective management strategies. This underscores the need for novel, targeted therapeutic approaches. Current treatment in gastroenterology often relies on conventional analgesics, including opioids, which are associated with adverse effects and limited long-term efficacy. As a result, alternative pharmacological options need to be explored. Neuromodulators, such as tricyclic antidepressants and gabapentinoids, have demonstrated therapeutic benefit, particularly in the context of central sensitization. Advances in the understanding of molecular mediators, including neurokinins, have prompted the development of receptor-targeted therapies. Nonetheless, clinical evidence remains limited and warrants further investigation. In parallel, non-pharmacological strategies, including neurostimulation and psychotherapy, are being explored. Collectively, these emerging approaches underscore the need for a mechanism-based, multimodal treatment paradigm.

Background and purpose: To investigate the basal release of 6-nitrodopamine (6-ND) from human isolated ureter and the role of this novel catecholamine in the ureter contractility.

Experimental approach: Ureters from 67 brain-dead organ donors (40 males and 27 females) were used during kidney transplantation procedures. After retrieval, a 2-cm distal ureter segment was isolated and incubated in Krebs-Henseleit solution at 37°C with continuous oxygenation. Basal 6-ND release was measured using liquid chromatography-tandem mass spectrometry. Studies were performed on 5-mm ureter rings mounted in tissue baths with isometric tension recorded via PowerLab system. Tyrosine hydroxylase (TH), S100, Pgp9.5 and eNOS expression were analysed using immunohistochemistry and fluorescence in situ hybridization (FISH).

Key results: The basal release of 6-ND was significantly reduced in epithelium-denuded compared with intact-epithelium samples. 6-ND induced concentration-dependent contractions of human ureter rings (pEC₅₀ 5.3 ± 0.2). In addition, 6-ND at 10 and 100 nM significantly potentiated contractions induced by noradrenaline and at 1 and 10 nM by adrenaline. TH was detected in epithelial cells of all human ureter samples (n = 5), with moderate to strong positivity. TH expression was confirmed by FISH. S100 and Pgp9.5 immunostaining revealed distinct patterns of nerve fibres in the tunica media and adventitia, while eNOS and TH were both expressed in the mucosal epithelium, with eNOS mainly at the surface and TH towards the basal layer.

Conclusions and implications: The finding that 6-ND is released by human ureter and modulates ureter smooth muscle contractility offers a novel insight on ureteral peristalsis mechanisms.

Background and purpose: Opioids targeting the μ opioid receptor remain largely ineffective in neuropathic pain conditions, emphasizing the need for novel therapeutic strategies. MP135 was reported to reduce thermal nociception in naive animals by activating μ-δ opioid receptor heteromers. In this study, we compared its pharmacological profile and antinociceptive properties in naive and neuropathic conditions to those of the μ-δ biased agonist CYM51010 and the μ opioid agonist morphine.

Experimental approach: Ligand affinity and activation of the G protein and β-arrestin pathways were determined using opioid receptors in their native environment. The impact of acute administration on thermal and mechanical nociceptive thresholds was evaluated in naive male and female mice. The impact on mechanical threshold and respiratory depression was also evaluated in mice with sciatic nerve injury. Pharmacological selectivity was established using μ or δ opioid receptor knock-out mice.

Key results: The three drugs showed similar binding profile and activation of G protein-dependent pathways. However, only MP135 and CYM51010 activated the β-arrestin pathway. In naive female mice, the drugs induced shorter thermal antinociception together with reduced maximal efficacy for morphine and MP135. In neuropathic conditions, morphine and MP135 were respectively poorly effective or ineffective whereas CYM51010 increased the mechanical threshold. The three drugs induced respiratory depression.

Conclusion and implications: The antinociceptive effect was receptor selective and affected by sex and neuropathic condition. This was unexpected based on the drug ex vivo pharmacological profiles and emphasizes the shortcomings of cell-based approaches to reliably predict behavioural responses.

Background and purpose: Severe dengue is characterised by systemic inflammation, cytokine storm, vascular leakage and haemorrhagic manifestations, largely driven by the host immune response to dengue virus (DENV) infection. Despite its burden, no licensed antivirals or host-directed therapies are currently available. Our group has previously identified Annexin A1 (AnxA1) as an endogenous regulator of inflammation in dengue. Treatment with the AnxA1 peptidomimetic, Ac_2-26, improved clinical outcomes in murine models of severe dengue by promoting resolution of inflammation without affecting viral control.

Experimental approach: To explore new delivery strategies, we developed a novel formulation of Ac_2-26 complexed with hydroxypropyl-β-cyclodextrin (CDX-Ac_2-26).

Key results: In DENV-2-infected A129 mice, both intraperitoneal and oral CDX-Ac_2-26 improved clinical scores and reversed thrombocytopenia. Notably, CDX-Ac_2-26 reduced mast cell degranulation, MCPT-1 plasma levels and CCL2 expression in spleen, with no effect on viral titres, indicating a host-targeted mechanism and overcoming the anti-inflammatory effects of the free peptide. Intraperitoneal administration achieved the same efficacy as oral dosing with only one-third of the dose. Importantly, the combination of CDX-Ac_2-26 with the antiviral nucleotide analogue sofosbuvir fully prevented disease and mortality in infected mice, highlighting a combinatorial effect between host-directed and antiviral therapies.

Conclusion and implications: These findings underscore the therapeutic potential of anti-inflammatory/pro-resolving strategies in severe dengue and support the development of CDX-Ac_2-26 as a novel adjunctive treatment. Combining anti-inflammatory and antiviral approaches may enhance efficacy and reduce treatment-associated toxicity, offering a promising path for clinical translation.

Background and purpose: GABA_A receptors (GABA_ARs) are heteropentameric ion channels that control almost all CNS functions, including spinal nociception. Most GABA_ARs contain a γ2 subunit but differ in their α and β subunit composition. TPA023B is an α2/α3 subtype selective, non-sedative, positive allosteric modulator (PAM) with antihyperalgesic activity in rodents. The pharmacokinetic/pharmacodynamic (PK/PD) characteristics of its antihyperalgesic action are unknown.

Experimental approach: To establish the PK/PD relationship for the antihyperalgesic effects of TPA023B, blood and brain concentrations, and brain and spinal cord receptor occupancies (RO) were determined at various time points following the administration of single oral doses of TPA023B in mice, and correlated with the antihyperalgesic effects (increases in paw withdrawal thresholds to punctate mechanical stimuli). In addition, the potentiating effects of TPA023B on recombinant γ1- and γ2-containing GABA_ARs (γ1-GABA_ARs and γ2-GABA_ARs, respectively) were determined in electrophysiological (patch-clamp) and fluorometric (membrane potential-sensitive dye) assays.

Key results: Antihyperalgesic effects of TPA023B correlated well with blood and brain concentrations, and no signs of tolerance (clockwise hysteresis) were observed. However, antihyperalgesia did not correlate with receptor occupancy at γ2-GABA_ARs, suggesting that a relevant part of the antihyperalgesic action occurred through non-γ2-GABA_ARs. In this regard, experiments in heterologous expression systems revealed that TPA023B not only potentiates γ2 but also γ1 containing GABA_ARs.

Conclusions and implications: Antihyperalgesic effects of TPA023B do not undergo tolerance development. Besides γ2-GABA_ARs, γ1-GABA_ARs appear to contribute to the antihyperalgesic effects of TPA023B. γ1-GABA_AR selective PAMs may hence have a therapeutic potential in chronic pain conditions.

Background and purpose: Musculoskeletal pain is a significant burden with limited pain relief options. The mechanically activated ion channel Piezo2 plays a role in mechanical sensitization; however, there has been little progress in examining therapeutics that target Piezo2. The goal of this study was to assess the effectiveness of FM-dye in reducing acute inflammatory and osteoarthritic (OA) knee pain in mice through Piezo2.

Experimental approach: Wild-type or nociceptor-specific Piezo2 conditional knockout (Piezo2cko) mice were used. The complete Freund's adjuvant (CFA) model of acute inflammatory knee pain, the partial medial meniscectomy (PMX) OA model, and ageing-associated OA mouse models were used. Pain-related behaviours (knee hyperalgesia, weight bearing asymmetry) were established prior to intra-articular injection of FM-dye (5 nmol in 2.5 μl) or vehicle. In vivo calcium imaging of the L4 dorsal root ganglion (DRG) was performed using Na_V1.8-GCaMP6 mice in the CFA model.

Key results: In the CFA model, female and male mice intra-articularly injected with FM1-43 exhibited reduced knee hyperalgesia 90 min post-injection. In vivo calcium imaging of the DRG demonstrated a reduction in nociceptor responses to mechanical force applied to the knee of CFA mice following FM-dye. Following PMX, intra-articular injection of FM1-43 reduced knee hyperalgesia in wild-type mice but not in Piezo2cko mice; weight bearing asymmetry was also reduced. In mice with age-associated OA, intra-articular injection of FM-dyes reduced knee hyperalgesia.

Conclusion and implications: Inhibiting Piezo2 pharmacologically reduced pain-related behaviours in mouse models of inflammatory and OA knee pain, providing evidence of the therapeutic potential of targeting Piezo2.

Background and purpose: Breast cancer, one of the most common cancers in women, primarily manifests as estrogen receptor-positive tumours in post-menopausal women. Aromatase inhibitors (AIs) such as letrozole are the most effective standard adjuvant endocrine therapy. However, the majority of AI-treated patients experience musculoskeletal symptoms (AIMSS), which can lead to premature discontinuation of treatment. Well-characterized animal models are essential to better understand the various mechanisms of AIMSS.

Experimental approach: We studied the development of musculoskeletal symptoms in ovariectomized (OVX) female C57BL/6J mice treated chronically with letrozole. We performed evoked and non-evoked behavioural measurements and assessed the extent of estrogen dependence of these changes. Electrophysiological studies and histological analyses of sciatic nerves were performed. Finally, we investigated whether letrozole was associated with the development of hyperexcitability of nociceptive neurons and an increase in pro-inflammatory cytokines in dorsal root ganglia.

Key results: Increasing doses of letrozole led to the development of musculoskeletal symptoms in evoked and non-evoked pain-like behavioural tests. These symptoms appear to be largely mediated by the decrease in estrogen levels. In addition, duloxetine reversed many of these behavioural changes. These symptoms were associated with a reduction in compound muscle action potentials and a decrease in sensory nerve conduction with loss of small amyelinated fibres. Furthermore, an increase in the excitability of nociceptor neurons associated with inflammation in the DRGs was induced by letrozole.

Conclusion and implications: We characterized a relevant and translational mouse model of AIMSS to help exploring the cellular and molecular mechanisms of the pathophysiology of AIs toxicity.