British Journal of Pharmacology最新文献

Background and purpose: The contribution of obesity to pulmonary arterial hypertension (PAH) pathophysiology remains poorly understood. Adipose tissue synthesises estrogens via cytochrome P450 (CYP) 19A1 (aromatase), whereas circulating estrogens are metabolised in the lung by CYP1A1. This study investigated whether obesity predisposes to PAH through enhanced estrogen synthesis and metabolism.

Experimental approach: A normoxic, two-hit, rat model of obesity-associated pulmonary hypertension (PH) was developed, combining Sugen 5416 (Sugen, Su) with a high-fat diet (HFD). Estrogen levels in SuHFD rat plasma and epicardial adipose tissue (EAT) from PAH patients were quantified using LC-MS/MS. CYP1A1 expression was assessed in lung and cardiac adipose tissue from SuHFD rats and PAH patients. The therapeutic potential of the CYP1A1 inhibitor hesperetin was evaluated in vivo. Complementary studies used pulmonary artery smooth muscle cells (PASMCs) from PAH patients and Simpson-Golabi-Behmel syndrome (SGBS) adipocytes.

Key results: HFD-fed rats of both sexes developed mild PH, which Sugen moderately exacerbated. EAT from PAH patients exhibited up-regulated aromatase and CYP1A1 expression, along with elevated estrogen levels. Circulating estrone was increased in male SuHFD rats. Pulmonary CYP1A1 expression was elevated in SuHFD rats and PAH patients. Hesperetin attenuated obesity-associated PH, reducing CYP1A1 expression in SuHFD rat lungs and PAH PASMCs. CYP1A1 induction in female SuHFD rat pericardial adipose tissue and Sugen-treated SGBS adipocytes was also tempered.

Conclusion and implications: These findings implicate augmented estrogen production by adipose tissue and elevated pulmonary CYP1A1 expression in the pathogenesis of obesity-associated PH. CYP1A1 may represent a novel therapeutic target in obese PAH patients.

Background and purpose: Although the impact of nicotine on the dopaminergic system is well established, its effects on neural activity in the brain regions implicated in addiction remain unclear. The major objective of the study was to assess the impact of acute nicotine on neuronal and astrocytic metabolic activity in the prefrontal cortex, cerebral cortex and hippocampus of awake mice.

Experimental approach: Nicotine (0.0125-2.00 mg kg^-1) was administered subcutaneously to 2- to 2.5-month-old C57BL/6NCrl male mice. The neuronal and astrocytic metabolic activity was measured by infusing [1,6-¹³C₂]glucose and [2-¹³C]acetate, respectively, 15 min after injection, and monitoring amino acids labelling in the ¹H-[¹³C]-NMR spectrum of brain tissue extracts.

Key results: Nicotine perturbed glucose metabolism in a dose- and brain- region-dependent manner. At lower doses, it enhanced the rate of glucose oxidation in glutamatergic neurons in the hippocampus (0.0125 mg kg^-1) and prefrontal cortex (0.025 mg kg^-1), with no change in the cerebral cortex. In contrast, a higher nicotine dose (1.0 mg kg^-1) suppressed glutamatergic and GABAergic neurometabolic activity in all three brain regions. Nicotine did not affect the astrocytic metabolic activity at the lower dose (0.025 mg kg^-1) but suppressed it at the high dose (2.0 mg kg^-1).

Conclusions and implications: Nicotine has biphasic impacts on glutamatergic activity, enhancing excitatory activity at low doses but reducing both excitatory and inhibitory activity at higher doses. Most interestingly, acute nicotine increases neuronal excitability by shifting the excitation-to-inhibition balance in the prefrontal cortex, a critical component of the mesocortical circuitry.

Background and purpose: Hexokinase 2 (HK2) is a key enzyme linked to high tumour cell proliferation. Its inhibitors such as 3-bromopyruvic acid (3-BP) induce cancer cell death, highlighting HK2 modulation as potential anti-cancer treatment. However, standard chemotherapies often cause the emergence of senescent cancer cells, which goes along with cell metabolic reprogramming and treatment failure. This study explores whether targeting HK2 can induce cancer cell senescence and whether metabolic changes in senescent cancer cells are tied to the cellular HK2 status.

Experimental approach: The expression of hexokinase 1 (HK1) and HK2 was assessed using immunoblot and immunofluorescence analysis in cell lines and in primary murine breast cancer (BC) cells. The senescence-inducing potential of HK2 inhibition and the effect of chemotherapy-induced senescence on HK1 and HK2 expression were assessed. Cell-based approaches were complemented by analysing single-cell RNA sequencing data from BC patients.

Key results: BC cell sensitivity to HK2 inhibition did not correlate with HK2 expression levels. Consistently, senescence was linked to a decrease in HK2 and an increase in HK1 expression. Moreover, genetic knockdown of HK2 induced senescence, indicating that a change in the HK2/HK1 ratio drives, rather than results, from cellular senescence. This shift in HK2/HK1 ratio was confirmed in single-cell RNA sequencing data of BC biopsies.

Conclusions and implications: Expressional shifts in the HK2/HK1 ratio may serve as a novel marker for BC cell senescence. Whereas targeting HK2 shows promise in untreated cancers, senescence-inducing anti-cancer therapies may limit the effectiveness of HK2-targeted treatments in pre-treated cancer patients.

Background and purpose: Tentonin 3 (TTN3/TMEM150C) is a mechanosensitive ion channel that plays critical roles in mechanotransduction processes. TTN3 forms a tetramer with a predicted rectangular shape and a central pore. A conotoxin ρ-TIA and its synthetic analog, noxious mechanosensation blocker 1 (NMB-1), were initially developed to inhibit slowly adapting (SA)-type mechanically activated (MA) currents in dorsal root ganglion (DRG) neurons. Since TTN3 confers slowly-adapting MA currents in DRG neurons, both NMB-1 and ρ-TIA were hypothesized to inhibit TTN3.

Experimental approach: To record MA currents, a few micrometre step indentations were applied to HEK cells expressing TTN3. NMB-1 and ρ-TIA were applied to these cells to test their specific antagonism. Mutations of the conopeptides and TTN3 were made to identify underlying mechanisms of inhibition.

Key results: NMB-1 strongly inhibited TTN3, whereas ρ-TIA had only a weak effect, and neither peptide affected Piezo channels. Alanine-scanning mutagenesis coupled with electrophysiological assays pinpointed that a positively charged residue in NMB-1 and ρ-TIA is essential for their inhibitory action. Additionally, a glutamate residue (Glu126) near the pore entrance of TTN3 was identified as critical for the NMB-1 inhibitory action, suggesting a key electrostatic interaction between NMB-1 and TTN3. Molecular dynamics simulations further supported this electrostatic interaction between the peptide ligand and the channel protein.

Conclusions and implications: NMB-1 specifically blocks a mechanosensitive channel, TTN3, via electrostatic interaction. These findings offer mechanistic insights into the selective inhibition of TTN3 by NMB-1 and provide a foundation for developing therapeutic agents targeting TTN3-related channelopathies.

Background and purpose: d-cycloserine, N-methyl-d-aspartate/glutamate (NMDA) receptor co-agonist (GluN2A/GluN2B partial and GluN2C super-agonist), improves negative symptom of schizophrenia with narrow therapeutic window, but the mechanisms remains unclear.

Experimental approach: Effects of chronic d-cycloserine administration (2-5 mg·kg^-1) on sucrose preference of adult male rats were determined. Dose/concentration-dependent effects of acute/chronic administrations of d-cycloserine (25-300 μM and 2-25 mg·kg^-1) on expression of GluN2 subunits and associated transmission of l-glutamate/d-serine/GABA were determined using microdialysis in adult male rats, primary cultured astrocytes (male/female neonatal rats) and capillary immunoblotting.

Key results: d-cycloserine dose-dependently increased release of astroglial l-glutamate/d-serine and neuronal GABA in the thalamus and medial prefrontal cortex (mPFC) (d-serine > GABA > l-glutamate), according to intrinsic activities (GluN2C > GluN2A [but unaffected GluN2B]). Chronic d-cycloserine dose-dependently down-regulated GluN2C > GluN2B > GluN2A (according to affinity) and attenuated d-cycloserine-induced astroglial release of l-glutamate/d-serine, dose dependently (GluN2C > GluN2A). Chronic exposure (25 μM) d-cycloserine down-regulated GluN2C but increased GluN2C-related astroglial l-glutamate/d-serine release. Chronic exposure to >60μM d-cycloserine diminished GluN2C-related astroglial release but activated GluN2A-related release. Chronic administration of 2 but not 5-mg·kg^-1 d-cycloserine restored MK-801-induced decrease sucrose preference.

Conclusion and implications: Chronic d-cycloserine (25 μM and 2 mg·kg^-1) down-regulated GluN2C without affecting GluN2A/GluN2B but increased GluN2-related astroglial l-glutamate/d-serine release. Higher d-cycloserine dose (>60 μM; >5 mg·kg^-1) inactivated GluN2C, but increased GluN2A related astroglial release. These results indicate that dose-dependent activation and inactivation of GluN2C by d-cycloserine is possibly involved in its efficacy on negative symptom of schizophrenia, but with a narrow therapeutic window.

Background and purpose: Human adenovirus (HAdV) causes respiratory or gastrointestinal tract infections depending on the virus subtype. While HAdV infections are generally self-limiting in immunocompetent people, they can result in significant morbidity and mortality in immunocompromised adults and children. Due to the limited availability of effective therapeutic options, there is an urgent need for novel therapeutics to combat HAdV infection and mitigate its severity.

Experimental approach: Here, we have repurposed the clinically well-used antifungal, itraconazole, to control HAdV infection. We tested the antiviral potential of the itraconazole and the mTOR inhibitor Ku-63794 on the production of infectious HAdV in A549 and Caco-2 cells as well as human intestinal organoids (HIOs). Additionally, we evaluated the benefit of a combination of these host-directed drugs with the direct-acting antiviral brincidofovir.

Key results: Pharmacological treatment with itraconazole significantly reduced virus titres in different in vitro models, including HIOs. Treatment with itraconazole impairs HAdV entry by entrapping incoming virus particles in endolysosomes and by promoting autophagy in HAdV-infected cells. Moreover, combining itraconazole with brincidofovir, a cidofovir derivative currently under clinical evaluation for anti-HAdV applications, demonstrated a synergistic effect in reducing HAdV titres.

Conclusion and implications: Given the gastrointestinal toxicity associated with brincidofovir, its combination with the host-directed drug itraconazole allowed lower brincidofovir doses to be used to decrease HAdV titres, thereby minimizing adverse drug effects while maintaining antiviral efficacy.

Zhou, F., Xia, J., Liu, Y., He, W., Zhang, H., Keavney, B. D., Zi, M., Nguyen, B. Y., A. Mohamed, T. M., Miller, J. M., Abouleisa, R. R.E., Hille, S. S., Cartwright, E. J., Müller, O. J., Xu, H., Butterworth, S., & Wang, X. (2025). Stabilisation of PRCP by deubiquitinase-targeting chimera (DUBTAC) to replenish autophagy for ameliorating pathological cardiac hypertrophy. British Journal of Pharmacology, 182(21), 5317–5339. https://doi.org/10.1111/bph.70094

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Background and purpose: Guanylate cyclase-C (GC-C) is the receptor for endogenous (uro)guanylin peptides, bacterial toxins and pharmacological analogues. Receptor activation leads to intestinal fluid loss, but also activates an antiproliferative pathway and is a promising target in colorectal cancer therapy. The present study delineates the molecular mechanisms that regulate the intensity of the anion secretory response (ASR) to GC-C activation in the different segments of the murine ileocolon.

Experimental approach: To assess the ASR to the guanylin analogue linaclotide, isolated mucosa from the different segments of the ileocolon of cGMP-dependent kinase II (cGKII)-deficient and WT mice were studied electrophysiologically in Ussing-chambers. The mucosal expression pattern of different phosphodiesterases (PDEs) was measured by RT-PCR.

Key results: The ASR to linaclotide and 8-pCPT-cGMP was strongly dependent on the presence of cGKII in the ileum and proximal colon, but not in the mid and distal colon, where cGKII expression is low. The inhibition of cGMP-sensitive PDE3 completely prevented the linaclotide-induced ASR only in the mid and distal colon, demonstrating that GC-C dependent ASR occurs via an increase in cAMP in these segments, mediated by the cGMP-induced inhibition of PDE3. In addition, the cGMP-specific PDE9 was highly expressed in the distal colon, and its inhibition strongly enhanced the ASR to linaclotide.

Conclusions and implications: GC-C activation leads to CFTR-mediated ASR in all segments of the intestine. In the mid and distal colon ASR is strongly reduced by the low cGKII and high PDE9 expression, with the CFTR channel being activated via cAMP-mediated phosphorylation.