Goals and practicalities of immunoblotting and immunohistochemistry: A guide for submission to the British Journal of Pharmacology

Blockade of P2X7 receptors preserves blood retinal barrier integrity by modulating the plasmalemma vesicle-associated protein: Implications for diabetic retinopathy

BACKGROUND AND PURPOSE

Plasmalemma vesicle-associated protein (PLVAP) regulates transcytosis in vascular endothelial cells. PLVAP expression is increased in pathological conditions, such as diabetic retinopathy. P2X7 receptor antagonists have been shown to preserve blood-retinal barrier (BRB) integrity. Here, we have tested the hypothesis that PLVAP expression is tightly linked to P2X7 receptor activity, leading to breakdown of the BRB in an in vitro model of diabetic retinopathy.

EXPERIMENTAL APPROACH

We integrated network approaches with an in vitro model of diabetic retinopathy using primary human retinal microvascular endothelial cells (HRMECs). Cells were treated with a P2X7 receptor antagonist, JNJ47965567, and expression of several genes predicted to belong to the P2X7 receptor signalling network were assessed. Levels and localisation of PLVAP, VE-cadherin and zonula occludens-1 (ZO-1) in HRMECs were evaluated. In vivo, the effects of JNJ47965567 on PLVAP expression in the retinas of diabetic mice were assessed.

KEY RESULTS

High levels of glucose increased PLVAP expression in HRMECs, which was blocked by JNJ47965567. Furthermore, JNJ47965567 preserved VE-cadherin and ZO-1. In the choroidal vasculature of diabetic mice, PLVAP immunostaining was increased, compared to levels in non-diabetic mice. This increase was significantly attenuated by treatment with JNJ47965567 CONCLUSIONS AND IMPLICATIONS: This study showed that P2X7 receptor signalling is an important component of a complex gene regulatory network, including PLVAP, mediating the pathophysiology of diabetic retinopathy. The P2X7 receptor antagonist JNJ47965567 showed a good pharmacodynamic profile, suggesting that this approach could be of value in the treatment of diabetic retinopathy.

An optimised Bcl-3 inhibitor for melanoma treatment

BACKGROUND AND PURPOSE

Malignant melanoma is the most lethal form of skin cancer, characterised by a poor survival rate. One of the key factors driving the aggressive growth of melanoma cells is the elevated expression of the proto-oncogene Bcl-3. This study aims to optimise, evaluate and characterise a second-generation Bcl-3 inhibitor, using melanoma as a model to demonstrate its potential therapeutic efficacy.

EXPERIMENTAL APPROACH

We synthesised and screened a series of structural analogues and selected A27, the most promising candidate for further investigation. We assessed whether A27 disrupted the interaction between Bcl-3 and its binding partner, p50, and examined the subsequent effects on cyclin D1 expression. Additionally, we evaluated the impact of A27 on melanoma cell proliferation and migration in vitro, as well as its therapeutic efficacy in various in vivo melanoma models.

KEY RESULTS

Nuclear magnetic resonance (NMR) confirmed that A27 directly binds to Bcl-3, effectively inhibiting its function. By disrupting the Bcl-3/p50 interaction, A27 led to a significant down-regulation of cyclin D1 expression. In cellular assays, A27 markedly reduced proliferation and migration of melanoma cells. In vivo, treatment with A27 resulted in a substantial reduction in melanoma tumour growth, with no observed toxicity in treated animals.

CONCLUSIONS AND IMPLICATIONS

At present, no other Bcl-3 inhibitors exist for clinical application in the field of oncology, and as a result, our novel findings provide a unique opportunity to develop a highly specific drug against malignant melanoma to meet an urgent clinical need.

Vincamine ameliorates hepatic fibrosis via inhibiting S100A4-mediated farnesoid X receptor activation: based on liver microenvironment and enterohepatic circulation dependence

BACKGROUND AND PURPOSE

Vincamine has extensive biological and pharmaceutical activity. We examined the hepatoprotective effects and mechanisms by which vincamine suppresses hepatic fibrosis.

EXPERIMENTAL APPROACH

Hepatic stellate cells (HSCs), TGF-β stimulated, were cultured with either vincamine, farnesoid X receptor (NR1H4; FXR) agonist or antagonist. Further, C57BL/6 mice were given thioacetamide (TAA) to induce hepatic fibrosis and subsequently treated with vincamine or curcumin.

KEY RESULTS

Vincamine regulated the deposition of extracellular matrix (ECM), inflammatory factors and S100A4, and up-regulated FXR and TGR5 (GPBA receptor) in activated HSCs, by activating FXR. FXR deficiency blocked vincamine effect on FXR, TGR5, α-smooth muscle actin (α-SMA) and IL1R1 in activated LX-2 cells. Vincamine corrected ECM imbalance, inflammatory secretion and FXR/TGR5 down-regulation in activated LX-2 cells with stimulating medium from LPS-primed THP-1 cells. S100A4 deficiency increased FXR and TGR5, and decreased IL-1β expression in activated THP-1. Further, S100A4 deficiency in activated macrophages could elevate FXR and TGR5 expression in activated LX-2, strengthening the impact of vincamine on α-SMA and IL-1β expression. Further, vincamine reduced serum ALT/AST levels, liver and intestinal histopathological changes, and caused ECM accumulation and protected the intestinal barrier in thioacetamide-induced hepatic fibrosis mice. Vincamine decreased inflammatory factors e.g. caspase 1 and IL-1β, and inhibited the S100A4-mediated FXR-TGR5 pathway.

CONCLUSION AND IMPLICATIONS

Vincamine significantly reverses hepatic fibrosis via inhibiting S100A4 involved in the crosstalk between macrophages and HSCs, and by activating the FXR-TGR5 pathway. Targeting the S100A4-mediated FXR dependence on modulating the liver environment may be the key target of vincamine in inhibiting hepatic fibrosis.

SEW2871 attenuates myocyte necroptosis in heart failure through inhibition of oxidative stress and inflammatory cytokines

BACKGROUND AND PURPOSE

Sphingosine-1-phosphate (S1P)/S1P receptor signalling exerts cardioprotective effects. However, the effect of the selective S1P1 receptor agonist SEW2871 on myocyte necroptosis in heart failure and the underlying mechanisms are unknown. In the present study, we tested the hypothesis that SEW2871 attenuates myocyte necroptosis in heart failure through inhibition of oxidative stress and inflammatory cytokines.

EXPERIMENTAL APPROACH

Eight-week-old male C57BL/6J mice underwent myocardial infarction (MI) or sham operation. The animals were randomized to receive SEW2871 (5 mg·kg-1·day-1, i.p) or placebo for 4 weeks.

KEY RESULTS

MI mice exhibited the increases in left ventricular (LV) end-diastolic dimension, LV end-systolic dimension, LV mass and lung weight and a decrease in LV ejection fraction, indicating LV dilation, LV systolic dysfunction and lung congestion, and these alterations were attenuated by the SEW2871 treatment. Myocardial expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, inflammatory cytokines tumour necrosis factor-α (TNF-α), interleukin-1β and interleukin-6, and phosphorylated RIPK1 (p-RIPK1), p-RIPK3 and p-MLKL, reflective of their respective kinase activities, markers of necroptosis, was markedly increased in the MI placebo group, and the increase was abolished by the SEW2871 treatment. Similarly, intracellular levels of reactive oxygen species, inflammatory cytokines, p-RIPK1, p-RIPK3 and p-MLKL protein expression were increased in H9C2 cardiomyocytes under mimic ischaemia and the increases were prevented by the SEW2871 treatment.

CONCLUSION AND IMPLICATIONS

The selective S1P1 receptor agonist SEW2871 attenuates myocyte necroptosis through inhibition of oxidative stress and inflammatory cytokines, leading to improvement of LV remodelling and function in heart failure.

Hydroethanolic extract of Spondias mombin L. leaves attenuates alveolar bone loss and inflammation in a model of periodontitis induced in male Wistar rats

OBJECTIVE

This study investigated the anti-inflammatory and antiresorptive effects of hydroethanolic extract of Spondias mombin L. in an experimental model of periodontitis.

DESIGN

Sixty-three male Wistar rats were divided into five groups: 1) Control, 2) Periodontitis, 3) Periodontitis + Spondias mombin L. 50 mg/kg, 4) Periodontitis + Spondias mombin L. 100 mg/kg, 5) Periodontitis + Spondias mombin L. 200 mg/kg. Periodontitis was induced through the placement of a ligature in the cervical region of the left maxillary second molar. The rats received the extract by oral gavage for 10 days and euthanasia was performed on the 11th day of the experiment. Blood samples were used for biochemical analysis, hemi-maxillae for micro-computed tomography and histological evaluation, and gingival tissue for cytokine and RT-qPCR analyses.

RESULTS

Administration of the extract reduced linear alveolar bone loss at a dose of 100 mg/kg (p = 0.0160) and improved bone volumetric parameters, such as integrity (BV/TV%) and trabecular porosity, at doses of 100 mg/kg (p = 0.0180) and 200 mg/kg (p = 0.0117). Trabecular separation was also improved at a dose of 200 mg/kg (p = 0.0405). Rats treated with 200 mg/kg showed better histological parameters (p = 0.0274). There was a reduction in the dosage of the pro-inflammatory cytokine interleukin 1β at doses of 50 mg/kg (p = 0.0496) and 100 mg/kg (p = 0.0374).

CONCLUSIONS

Our findings suggest an anti-inflammatory and antiresorptive effect of the hydroethanolic extract of Spondias mombin L. administered to rats with periodontitis, without altering blood biochemical markers.

Systemic EP4 receptor agonist and Arginase-1 therapy in a murine model of chronic asthma and influenza virus-induced asthma exacerbation

BACKGROUND AND PURPOSE

Myeloid-derived suppressor cells (MDSCs) play important roles in the pathogenesis of asthma. Recent studies demonstrate that their function can be modulated by different pharmacological approaches. In this study, we focussed on the effects of systemically administered prostaglandin EP4 receptor agonist L-902,688 and pegylated human Arginase-1 on MDSCs in a murine model of chronic asthma and asthma exacerbation.

EXPERIMENTAL APPROACH

BALB/c mice were challenged with house dust mite (HDM) over a period of 5 weeks, establishing a chronic asthma phenotype. To induce asthma exacerbation, mice were infected with Influenza Virus H1N1 A/Puerto Rico/8/1934. In vivo lung function, lung inflammatory features, number and suppressive activity of MDSCs, number of different T cell subsets in lung and spleen and viral titer in the bronchoalveolar lavage fluid (BALF) were assessed.

KEY RESULTS

In asthmatic mice, treatment with the EP4 receptor agonist or Arginase-1 significantly reduced the number of eosinophils in the BALF. Both treatments improved lung function and ameliorated airway hyperresponsiveness (AHR) in asthma exacerbation. The number and suppressive activity of MDSCs in the lung were increased by virus-induced asthma exacerbation.

CONCLUSION AND IMPLICATIONS

We found beneficial effects of systemic EP4 receptor agonist and Arginase-1 therapy in a murine model of chronic asthma and influenza virus-induced asthma exacerbation. Our findings highlight the potential efficacy of EP4 receptor agonists, Arginase-1, and MDSCs, as novel therapeutic approaches in asthma and asthma exacerbation.

Clemastine attenuates subarachnoid haemorrhage pathology in a mouse model via Nrf2/SQSTM1-mediated autophagy

BACKGROUND AND PURPOSE

Subarachnoid haemorrhage (SAH) is an uncommon and severe subtype of stroke, but the availability of drugs for its treatment is limited. Enhanced autophagy is believed to attenuate SAH pathology; however, autophagy level is tentatively up-regulated and then down-regulated after SAH onset in mice. Clemastine, a first-generation histamine H1R antagonist, is believed to persistently enhance autophagy. However, the precise mechanism of clemastine in the treatment of SAH remains largely elusive.

EXPERIMENTAL APPROACH

Haemoglobin-induced neuron injury model and autologous-blood-injected SAH-model mice were used to investigate the effects of clemastine in vitro and in vivo, respectively. The expressions of Nrf2/Keap1 and autophagy-related proteins were detected using western blotting and immunofluorescence. Neuronal injury and hyperoxide level were measured via Fluoro-Jade C and dihydroethidium staining. Neurological behaviours were evaluated using modified Garcia Scale, beam balance test, Morris water maze, Y-maze and novel object recognition test. The structures of autophagosomes and mitochondria were visualised using transmission electron microscope. The binding sites of clemastine was predicted and verified using database and drug affinity-responsive target stability.

KEY RESULTS

Clemastine ameliorated SAH pathogenesis in vivo and in vitro. Moreover, the intraperitoneal injection of clemastine and its oral administration reduced neuronal death and improved cognitive deficits in SAH-model mice. Mechanistically, clemastine directly bound to muscarinic acetylcholine receptor M4, prevented Nrf2 degradation via Nrf2/Keap1/SQSTM1 pathway and promoted Nrf2 nuclear translocation, thus enhancing autophagy-related gene transcription and autophagy activation.

CONCLUSIONS AND IMPLICATIONS

Clemastine can attenuate SAH pathology via the activation of Nrf2/SQSTM1 autophagy and could be a useful therapeutic in the context of SAH.

Targeting FDX1 by trilobatin to inhibit cuproptosis in doxorubicin-induced cardiotoxicity

BACKGROUND AND PURPOSE

Doxorubicin (DOX), an anthracycline chemotherapeutic agent, whose use is limited owing to its dose-dependent cardiotoxicity. Mitochondrial oxidative stress plays a crucial role in the pathogenesis of DOX-induced cardiotoxicity (DIC). Trilobatin (TLB), a naturally occurring food additive, exhibits strong antioxidant properties, but its cardioprotective effects in DIC is unclear. This study investigates the cardioprotective effect of TLB on DIC.

EXPERIMENTAL APPROACH

DOX was used to generate an in vivo and in vitro model of cardiotoxicity. Echocardiography, enzyme-linked immunosorbent assay (ELISA) and haematoxylin and eosin (H&E) staining were used to evaluate the cardiac function in these models. To identify the targets of TLB, RNA-sequence analysis, molecular dynamics simulations, surface plasmon resonance binding assays and protein immunoblotting techniques were used. Transmission electron microscopy, along with dihydroethidium and Mito-SOX staining, was conducted to examine the impact of trilobatin on mitochondrial oxidative stress. SiRNA transfection was performed to confirm the role of ferredoxin 1 (FDX1) in DIC development.

KEY RESULTS

In DIC mice, TLB improved cardiac function in a dose-dependent manner and inhibited myocardial fibrosis in DIC mice. TLB also attenuated DOX-induced mitochondrial dysfunction and reduced cardiac mitochondrial oxidative stress. TLB was found to directly bind to FDX1 and suppresses cuproptosis after DOX treatment, causing significant inhibition of cuproptosis-related proteins.

CONCLUSIONS AND IMPLICATIONS

This is the first study to show that TLB strongly inhibits DIC by reducing mitochondrial oxidative stress and controlling DOX-mediated cuproptosis by targeting FDX1. Therefore, TLB is as a potential phytochemical cardioprotective candidate for ameliorating DIC.

Engineered pulmonary artery tissues for measuring contractility, drug testing and disease modelling

BACKGROUND AND PURPOSE

Vasoreactivity of pulmonary arteries regulates blood flow through the lungs. Excessive constriction of these vessels contributes to pulmonary arterial hypertension (PAH), a progressive and incurable condition, resulting in right heart failure. The search for new and improved drug treatments is hampered by laboratory models that do not reproduce the vasoactive behaviour of healthy and diseased human arteries.

EXPERIMENTAL APPROACH

We have developed an innovative technique for producing miniature, three-dimensional arterial structures that allow proxy evaluation of human pulmonary artery contractility. These "engineered pulmonary artery tissues" or "EPATs" are fabricated by suspending human pulmonary artery vascular smooth muscle cells (VSMCs) in fibrin hydrogels between pairs of silicone posts, located on custom-made racks, in 24-well culture plates.

KEY RESULTS

EPATs exhibit rapid, robust and reproducible contraction responses to vasoconstrictors (KCl, ET-1, U46619) as well as relaxation responses to clinically approved PAH vasodilatory drugs that target several signalling pathways, such as bosentan, epoprostenol, selexipag and imatinib. EPATs composed of pulmonary artery VSMCs from PAH patients exhibit enhanced contraction to vasoconstrictors and relaxation in response to vasodilators. We also demonstrate the incorporation of endothelial cells into EPATs for the measurement of endothelium-dependent dilatory responses.

CONCLUSION AND IMPLICATIONS

We demonstrate the capacity and suitability of EPATs for studying the contractile behaviour of human arterial cells and preclinical drug testing. This novel biomimetic platform has the potential to dramatically improve our understanding and treatment of cardiovascular disease.

Imatinib aggravates pressure-overload-induced right ventricle failure via JNK/Runx2 pathway

BACKGROUND AND PURPOSE

Right ventricular (RV) function is the key prognostic determinant of pulmonary hypertension (PH). In PH patients, imatinib treatment decreases pulmonary vascular resistance and improves exercise capacity, but does not change mortality or duration to clinical worsening. Imatinib has been reported to be cardiotoxic in the left heart. We hypothesise that imatinib damages the pressure overloaded RV via its direct effects within the heart, which may counteract its therapeutic effects in haemodynamic improvement of PH.

EXPERIMENTAL APPROACH

A pulmonary arterial banding (PAB) rat model with fixed pulmonary artery narrowing was performed to avoid changes in RV afterload.

KEY RESULTS

In PAB rats, imatinib treatment decreased the survival rate and exacerbated RV dysfunction, myocardial hypertrophy, apoptosis and fibrosis. In vitro, imatinib increased cardiomyocyte hypertrophy and did not change cardiac fibroblasts activation; however, imatinib-treated conditioned medium from cardiomyocytes promoted fibroblast activation. Mechanistically, imatinib increased the phosphorylation of c-jun N-terminal kinase (JNK) and the expression of RUNX family transcription factor 2 (Runx2), and subsequently promoted the transcription of thrombospondin 4 (THBS4) and connective tissue growth factor (CTGF) in RV cardiomyocytes. Finally, SP600125, a JNK inhibitor, significantly alleviated imatinib-induced RV failure in PAB rats and enhanced the effects of imatinib on RV function improvement in SU5416 + hypoxia-induced PH rats without affecting pulmonary artery narrowing.

CONCLUSION AND IMPLICATIONS

We demonstrate for the first time that imatinib aggravates RV failure under pressure overload through JNK/Runx2 pathway, and JNK inhibition improves the therapeutic effects of imatinib on RV function in PH.

Novel FKBP prolyl isomerase 1A (FKBP12) ligand promotes functional improvement in SOD1G93A amyotrophic lateral sclerosis (ALS) mice

BACKGROUND AND PURPOSE

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease with limited treatment options. ALS pathogenesis involves intricate processes within motor neurons, characterized by dysregulated Ca2+ influx and buffering in early ALS-affected motor neurones. This study proposes the modulation of ryanodine receptors (RyRs), key mediators of intracellular Ca2+, as a therapeutic target.

EXPERIMENTAL APPROACH

A novel class of novel FKBP12 ligands that show activity as cytosolic calcium modulators through stabilizing RyR channel activity, were tested in the superoxide dismutase 1 (SOD1)G93A mouse model of ALS. Different outcomes were used to assess treatment efficacy, including electrophysiology, histopathology, neuromuscular function and survival.

KEY RESULTS

Among the novel FKBP12 ligands, MP-010 was chosen for its central nervous system availability and favourable in vitro pharmaco-toxicological profile. Chronic administration of MP-010 to SOD1G93A mice produced preservation of motor nerve conduction, with the 61-mg·kg-1 dose significantly delaying the onset of motor impairment. This was accompanied by improved motor coordination, increased innervated endplates and significant preservation of motor neurones in the spinal cord of treated mice. Notably, MP-010 treatment significantly extended lifespan by an average of 10 days compared to vehicle.

CONCLUSIONS AND IMPLICATIONS

FKBP12 ligands, particularly MP-010, exhibit promising neuroprotective effects in ALS, highlighting their potential as novel therapeutic agents. Further investigations into the molecular mechanisms and clinical translatability of these compounds are needed for their application in ALS treatment.

Sex differences in the vasoactive effect of transient receptor potential channels: TRPM3 as a new therapeutic target for (neuro)vascular disorders

BACKGROUND AND PURPOSE

Sex-dependent vascular effects of transient receptor potential (TRP) channels and sex dimorphism in migraine are not yet fully characterized. We investigated the differential vasoactive effects of TRP ankyrin 1 (TRPA1), TRP melastatin 3 (TRPM3) and TRP vanilloid 1 (TRPV1) channels, their pharmacological mechanism(s), and localization and expression in human isolated blood vessels.

EXPERIMENTAL APPROACH

Agonist responses to cinnamaldehyde (TRPA1), pregnenolone sulfate (PregS, TRPM3) or capsaicin (TRPV1) were analysed using wire myography in segments of human coronary (HCAs) and middle meningeal (HMMAs) arteries from men and women. The mechanisms involved in these responses were investigated using the antagonists/blockers/inhibitors: HC-030031 (TRPA1), isosakuranetin (TRPM3), capsazepine (TRPV1), olcegepant (calcitonin gene-related peptide [CGRP] receptor), L-NAME (nitric oxide synthase [NOS]), indomethacin (cyclooxygenase [COX]), TRAM-34 + apamin (K+ channels) or MK-801 (N-methyl-d-aspartate [NMDA] receptor). Fluorescence microscopy, quantitative polymerase chain reaction (qPCR), and western blotting were performed to investigate their location and expression, respectively.

KEY RESULTS

In HCAs and HMMAs, (i) capsaicin-induced relaxation remained unchanged after the above-mentioned antagonists/blockers/inhibitors and (ii) cinnamaldehyde-induced relaxation was blocked by olcegepant. PregS-induced maximal relaxation was significantly enhanced in isolated arteries from females compared with males and was inhibited after isosakuranetin, MK-801 or L-NAME. TRPM3 mRNA and protein expression, along with NMDA protein levels, were higher in arteries from females than males.

CONCLUSION AND IMPLICATIONS

Modulation of vascular tone in HCAs and HMMAs by activation of TRPM3 is sex-dependent, likely involving NMDA receptors. This represents a new therapeutic direction, targeting sex dimorphism in migraine and its related cardiovascular events.

TREM2 activation reduces white matter injury via PI3K/Akt/GSK-3β signalling after intracerebral haemorrhage

BACKGROUND

White matter injury (WMI) considerably exacerbates the prognosis following intracerebral haemorrhage (ICH). While the triggering receptor on myeloid cells 2 (TREM2) is recognized for its neuroprotective roles in a range of neurological disorders through the modulation of neuroinflammation, phagocytosis, promoting cell survival, its specific function in WMI after ICH has yet to be fully elucidated.

METHODS

This study involved inducing ICH in mice through autologous blood injection. Neurological functions were tested via behavioural assessments and electrophysiological recordings. WMI was examined using immunofluorescence, Luxol fast blue staining, MRI and transmission electron microscopy. Microglia were isolated and analysed using real-time polymerase chain reaction (PCR). Microglia depletion was achieved with PLX3397, primary cultures of microglia and oligodendrocytes were investigated.

RESULTS

The activation of TREM2 resulted in improved neurological outcomes after ICH, correlated with reduced WMI, demonstrated by decreased white matter loss in the corpus striatum, reduced damage to the nodes of Ranvier, and better preservation of myelin and white matter tract integrity. These neuroprotective effects were attributed to changes in microglial states mediated via the PI3K/Akt/GSK-3β signalling pathway. However, the neuroprotective advantages conferred by TREM2 activation were negated in TREM2 KO mice, either through microglia depletion or inhibition of PI3K.

CONCLUSIONS

This research is the first to illustrate that TREM2 activation mitigates WMI following ICH through a microglia-dependent mechanism involving the PI3K/Akt/GSK-3β pathway. TREM2 represents a potential therapeutic target for ICH.

Casdatifan (AB521) is a novel and potent allosteric small molecule inhibitor of protumourigenic HIF-2α dependent transcription

BACKGROUND AND PURPOSE

Hypoxia-inducible factor 2α (HIF-2α) is a transcription factor that mediates the expression of genes critical for cell adaptation and survival in low oxygen (hypoxic) conditions. In cancer, hypoxic conditions or molecular alterations within cancer cells can lead to HIF-2α accumulation and promote tumour growth and progression. Inactivating mutations in the von Hippel-Lindau (VHL) gene disable the oxygen-dependent HIF-2α degradation pathway and cause constitutive HIF-2α activity. VHL mutations are prevalent in clear cell renal cell carcinoma (ccRCC) where HIF-2α is a known tumourigenic driver. HIF-2α inhibition was shown to improve ccRCC patient outcomes clinically, warranting development of next-generation inhibitors.

EXPERIMENTAL APPROACH

Pharmacological effects of a novel small molecule allosteric inhibitor of HIF-2α, AB521 (casdatifan), were evaluated using in vitro cell-based assays and in vivo mouse models.

KEY RESULTS

AB521 inhibited HIF-2α-mediated transcription in cancer cells, endothelial cells, and M2-polarised macrophages. AB521 was selective for HIF-2α, displaying no activity against HIF-1α, and did not exhibit off-target cytotoxicity. When delivered orally to mice, AB521 caused dose-dependent decreases in HIF-2α-associated pharmacodynamic markers and significant regression of human ccRCC xenograft tumours. AB521 combined favourably with cabozantinib, a standard of care tyrosine kinase inhibitor, or zimberelimab, a clinical-stage anti-PD-1 antibody, in ccRCC xenograft studies.

CONCLUSIONS AND IMPLICATIONS

AB521 is a potent, selective and orally bioavailable HIF-2α inhibitor, with favourable pharmacological properties, that is being explored clinically for the treatment of ccRCC.

Dopamine D3 receptor blockade accelerates the extinction of opioid withdrawal-induced drug-seeking behaviours and alters microglia in dopaminoceptive nuclei

BACKGROUND AND PURPOSE

Among all drugs of abuse, opioids cause most of the deaths and treatment seeking. Despite abundant research in multifaceted therapeutic strategies, a high rate of relapse still characterises this condition. Dopamine D3 receptor antagonists combined with cue-exposure therapies have been proposed to ameliorate the abused drugs-induced cognitive deficits, which consequently would aid to prevent the maladaptive behaviours responsible for drug use.

EXPERIMENTAL APPROACH

We used the morphine withdrawal-induced conditioned place aversion (CPA) paradigm to assess, in male rats, the efficacy of D3 receptor blockade to improve the extinction of drug-seeking behaviours associated with the aversive contextual stimuli of its withdrawal. Then, using immunohistochemical methods, we evaluated the participation of neuroimmune mechanisms in the striatum and infralimbic cortex in D3 receptor modulation of CPA extinction.

KEY RESULTS

Whereas the selective D3 antagonist PG01037 accelerated the extinction of the morphine withdrawal-induced CPA, our findings indicate that decreased motivation might be involved in this action. Increased D3 receptor expression in glial cells and the modulation of microglia activation state in specific dopaminoceptive areas could intervene in the behavioural outcomes of D3 receptor blockade.

CONCLUSIONS AND IMPLICATIONS

Our findings reveal a facilitatory role of D3 antagonists in the inhibition of morphine-seeking behaviours triggered by contextual stimuli associated with its withdrawal. Nonetheless, their potential ability to reduce motivation might influence their therapeutic use. Future investigations elucidating the precise function of D3 receptors will facilitate the identification of this receptor as a valuable therapeutic target for mitigating the recurrence of opioid withdrawal-induced drug-seeking behaviour.

Matrix metalloproteinase inhibition protects against junctophilin-2 proteolysis during doxorubicin-induced cardiotoxicity

BACKGROUND AND PURPOSE

Treatment of cancer patients with anthracyclines is known to cause dose-dependent cardiotoxicity through several mechanisms including enhanced oxidative stress, ultimately resulting in defective excitation-contraction coupling. Loss of junctophilin-2 (JPH-2), which tethers transverse tubules (T-tubules) to the sarcoplasmic reticulum, is a feature of doxorubicin-induced cardiotoxicity, yet the protease involved in unclear. As activation of matrix metalloproteinase-2 (MMP-2) is known to contribute to doxorubicin-induced cardiotoxicity, we investigated here the role of MMP-2 in JPH-2 proteolysis and defective calcium transients in it.

EXPERIMENTAL APPROACH

C57BL/6J mice were treated with doxorubicin for 4 weeks with or without the MMP inhibitor (doxycycline), MMP-2 preferring inhibitor (ONO-4817) or vehicle, and cardiac function was assessed using echocardiography. JPH-2 levels in ventricular extracts were measured. Calcium transients and JPH-2 levels were measured in neonatal rat ventricular cardiomyocytes treated with doxorubicin and ONO-4817.

KEY RESULTS

Both MMP inhibitors attenuated doxorubicin-induced cardiac systolic and diastolic dysfunction. Doxorubicin treatment resulted in JPH-2 cleavage in mouse hearts as evidenced by the appearance of lower molecular weight products of 63 and 25 kDa, which was prevented by MMP inhibitors. Loss of JPH-2 and impaired calcium transients were observed in neonatal rat ventricular cardiomyocytes treated with doxorubicin, while ONO-4817 attenuated these changes. In silico analysis predicted cleavage sites between JPH-2 MORN repeats and within its unstructured region.

CONCLUSIONS AND IMPLICATIONS

These results reveal that JPH-2 proteolysis is a consequence of MMP-2 activation and highlight the beneficial prophylactic action of two orally available MMP inhibitors in preventing doxorubicin-induced cardiotoxicity.

Contributions of synaptic energetic dysfunction by microtubule dynamics and microtubule-based mitochondrial transport disorder to morphine tolerance

BACKGROUND AND PURPOSE

Morphine is among the most powerful analgesic, but its long-term use can cause tolerance. Synaptic ATP supply is critical for maintaining synaptic transmission. Microtubule-based mitochondrial transport ensures synaptic energy supply. How synaptic energy changes with morphine and the role of microtubule tracks in synaptic mitochondrial energy supply remain elusive. Chronic morphine treatment can destroy microtubule cytoskeletons. We investigated the effect of the microtubule cytoskeleton on synaptic mitochondrial energy supply and the mechanism of microtubule dynamics after morphine exposure.

EXPERIMENTAL APPROACH

Rats were treated with long-term morphine and the effect on thermal pain thresholds was evaluated by the tail-flick latency test. Various antagonists and agonists were used elucidated the role and mechanism of synaptic mitochondrial energy supply and microtubules in morphine tolerance in vivo and in SH-SY5Y cells.

KEY RESULTS

Chronic morphine treatment reduced synaptic mitochondrial ATP production. Improving mitochondrial oxidative phosphorylation (OXPHOS) alleviated the downregulation of synaptic ATP levels. Microtubule-stabilizing agents prevented microtubule disruption and ameliorated synaptic energy deficit via microtubule-based microtubule transport. In SH-SY5Y cells, morphine exposure reduced microtubule expression. And re-opening the synaptic Ca2+ channel by agonist alleviated microtubule decrease by calcium/calmodulin-dependent protein kinase 2 (CAMKK2)/AMP-activated protein kinase (AMPK) pathway.

CONCLUSION AND IMPLICATIONS

This study demonstrates that the microtubule cytoskeleton regulated by the Ca2+-CAMKK2-AMPK axis is critical for synaptic mitochondrial transport and ATP production, explaining an interplay between chronic morphine-induced abnormal neuroadaptation and synaptic energetic dysfunction. These findings implicated a potential clinical strategy for prolonging the opioid antinociceptive effect during long-term pain control.

A novel synthesised STAT3 inhibitor exerts potent anti-tumour activity by inducing lysosome-dependent cell death

BACKGROUND AND PURPOSE

Signal transducer and activator of transcription 3 (STAT3) has emerged as a promising therapeutic target for triple-negative breast cancer (TNBC) and multiple myeloma (MM), yet no STAT3-selective drugs have been approved for clinical use.

EXPERIMENTAL APPROACH

Newly synthesized compounds were screened by docking, surface plasmon resonance (SPR) and cellular thermal shift assay (CETSA) to measure the binding activity with STAT3. RNA-Seq, luciferase assays, western blot and immunofluorescence assays were conducted to detect the impact of RDp002 on STAT3 signalling. CCK-8, cell cycle, apoptosis assays and transwell were utilised to evaluate the anti-tumour activity of RDp002 in vitro. Xenograft models were used to assess the effectiveness of RDp002 in vivo. Various inhibitors were utilised to investigate how RDp002 causes tumour cell death. The human ether-à-go-go-related gene (hERG/Kv11.1) assays, blood biochemistry and acute toxicity experiments were conducted to explore the toxicity of RDp002.

KEY RESULTS

RDp002 exhibited had strong affinity for STAT3 and impaired the phosphorylation of STAT3 at tyrosine 705 and serine 727 residues. RDp002 suppressed the proliferation, survival, migration, growth and metastasis of TNBC and MM cells. RDp002 inhibited tumour cell viability primarily via lysosome-dependent cell death, which can be weakened by overexpression of STAT3. The toxicity of RDp002 in vivo was minimal based on results from hERG assays, blood biochemistry analysis and acute toxicity tests.

CONCLUSION AND IMPLICATIONS

RDp002 is a novel STAT3 inhibitor that exerts potent anti-tumour effects mainly by inducing lysosome-dependent cell death. RDp002 represents a promising therapeutic lead for TNBC and MM.

Metformin aggravates pancreatitis by regulating the release of oxidised mitochondrial DNA via the frataxin (FXN)/ninjurin 1 (NINJ1) signalling pathway

BACKGROUND AND PURPOSE

Patients with diabetes are at a higher risk of developing acute pancreatitis compared to those without diabetes. Therefore, it is essential to investigate the effects of metformin, a primary treatment for type 2 diabetes, on the progression of pancreatitis.

EXPERIMENTAL APPROACH

Network pharmacology was employed to investigate the potential effects of metformin on pancreatitis and to predict its underlying molecular mechanisms. Pharmacological and mechanistic studies of metformin were conducted utilising mtDNA depletion (ρ0) of 266-6 acinar cells, knockout mouse models and experimental models of both acute and chronic pancreatitis. The mitochondrial homeostasis and plasma membrane integrity were examined through phase-contrast microscopy and time-lapse video imaging.

KEY RESULTS

Network pharmacology analysis revealed that metformin possesses significant potential to modulate the pathogenesis of pancreatitis, likely through its regulation of mitochondrial function and cell membrane morphology. Further, the results revealed that metformin augmented the release of oxidised mitochondrial DNA (Ox-mtDNA) by enhancing NINJ1-mediated plasma membrane rupture, which subsequently ignited a cascade of acinar cell necrosis. Metformin exacerbated mitochondrial iron imbalance by suppressing Frataxin, thereby worsening mitochondrial homeostasis disruption and Ox-mtDNA generation. NINJ1 knockout eliminated the metformin-induced acinar cell necrosis and elevation of Ox-mtDNA levels, and mtDNA depletion reversed the effect of metformin on acinar cell death.

CONCLUSION AND IMPLICATIONS

Metformin exacerbates both acute and chronic pancreatitis, possibly because of increased release of Ox-mtDNA via modulation of mitochondrial iron homeostasis and NINJ1-mediated plasma membrane rupture, suggesting that extreme caution should be exercised when using metformin in diabetic patients with pancreatitis.

Unlocking the power of immune checkpoint inhibitors: Targeting YAP1 reduces anti-PD1 resistance in skin cutaneous melanoma

BACKGROUND AND PURPOSE

Immune checkpoint inhibitors, such as anti-PD1, revolutionized melanoma treatment. However, resistance and low response rates remain problems. Our goal was to pinpoint actionable biomarkers of resistance to anti-PD1 treatment and verify therapeutic effectiveness in vivo.

EXPERIMENTAL APPROACH

Using receiver operating characteristic (ROC) and survival analysis in a database of 1434 samples, we identified the strongest resistance-associated genes. Inhibitors were evaluated in C57BL/6J mice using wild-type B16-F10, and BRAF, -PTEN, -CDKN2A-mutant YUMM1.7 melanoma cell lines. We investigated the synergistic impact of anti-PD1 therapy and yes-associated protein 1 (YAP1) inhibition by non-photoactivated Verteporfin. Tumour volume was determined at fixed cutoff points, normalized to body weights.

KEY RESULTS

In the anti-PD1-treated melanoma cohort, YAP1 was the strongest druggable candidate overexpressed in non-responder patients (ROC AUC = 0.699, FC = 1.8, P=1.1E-8). The baseline YAP1 expression correlated with worse progression-free survival (HR = 2.51, P=1.2E-6, FDR = 1%), and overall survival (HR = 2.15, P = 1.2E-5, FDR = 1%). In YUMM1.7, combination of Verteporfin plus anti-PD1 reduced tumour size more than anti-PD1 monotherapy (P=0.008), or control (P=0.021). There was no difference between the cohorts in B16-F10 inoculated mice. We found increased expression of YAP1 in YUMM1.7 mice compared to B16-F10. The combination therapy induced a more-immune-inflamed phenotype characterized by increased expression of T cell and M1 macrophage markers.

CONCLUSIONS AND IMPLICATIONS

Verteporfin with anti-PD1 exhibited antitumor potential by promoting a pro-inflammatory tumour microenvironment in melanoma. We believe that YAP1 acts as a master regulator of anti-PD1 resistance.

Involvement of Piezo 1 in inhibition of shear-induced platelet activation and arterial thrombosis by ginsenoside Rb1

BACKGROUND AND PURPOSE

Shear-induced platelet activation and aggregation (SIPA) play crucial roles in arterial thrombosis. Piezo1 is a mechanosensitive calcium channel that promotes platelet hyperactivation under pathological high-shear conditions. This study explores the function of platelet Piezo1 in SIPA and arterial thrombosis, and the inhibitory effects and mechanisms of ginsenoside Rb1 on these processes.

EXPERIMENTAL APPROACH

Transgenic mice with platelet-specific Piezo1 deficiency (Piezo1ΔPlt) were used to elucidate the role of platelet Piezo1 in SIPA and arterial thrombosis. A microfluidic channel system was employed to assess platelet aggregation, calcium influx, calpain activity, talin cleavage, integrin αIIbβ3 activation and P-selectin expression under shear flow. Cellular thermal shift assay was used to determine binding between Rb1 and Piezo1. Folts-like model in mice was used to evaluate antithrombotic effects of Rb1.

KEY RESULTS

Piezo1 deficiency in platelets reduced platelet activation and aggregation induced by a high shear rate of 4000 s-1 and attenuated arterial thrombosis induced by Folts-like mouse model. Rb1 inhibited SIPA with an IC50 of 10.8 μM. Rb1 inhibited shear-induced Ca2+-dependent platelet activation and aggregation, as well as thrombus formation in Folts-like model in Piezo1fl/fl mice. Rb1 significantly improved thermal stability of Piezo1 in platelets by binding to Piezo1. Treatment of Piezo1ΔPlt mice with Rb1 did not exhibit further inhibitory effects on SIPA and thrombosis.

CONCLUSION AND IMPLICATIONS

Platelet Piezo1 is essential for SIPA and arterial thrombosis induced by high shear. Rb1 exerted anti-platelet and anti-thrombotic effects at high shear rates via Piezo1 channels, providing a potential candidate as antiplatelet therapeutic agent.

Silencing drug transporters in human primary muscle cells modulates atorvastatin pharmacokinetics: A pilot study

BACKGROUND AND PURPOSE

Non-adherence to atorvastatin treatment is relatively common and partly due to statin-related myotoxicities (SRMs). The risk of developing SRM is dose- and concentration-dependent, highlighting the importance of atorvastatin pharmacokinetics. This study explored the inter-individual variabilities in expression of the atorvastatin transporter gene contributing to modulation of atorvastatin within the muscle cell.

EXPERIMENTAL APPROACH

mRNA levels of efflux and influx transporters were measured and modulated with siRNAs to evaluate effects on intracellular accumulation of atorvastatin in primary cultures of differentiated myotubes from 12 human volunteers.

KEY RESULTS

All genes assessed were expressed with a high inter-individual variability. In differentiated myotubes, efflux transporters were expressed at higher levels than the influx carriers. When considering efflux and influx transporters separately, ABCC1 and SLCO2B1 are the most highly expressed efflux and influx transporters. Suppression of ABCC1, ABCC4 and/or ABCG2 mRNA levels with siRNA significantly increased intracellular accumulation of atorvastatin in differentiated myotubes. Interestingly, the siRNA targeting ABCG2 had a moderate effect on intracellular accumulation of atorvastatin in a volunteer expressing the ABCG2 variant rs2231142 (c.421C>A, p.Gln141Lys). This hypothesis was further validated in a HEK recombinant model overexpressing ABCG2 either wild-type (421C) or variant (421A). Reduction of SLCO1B1 and SLCO2B1 mRNA levels significantly modified intracellular accumulation of atorvastatin in only some volunteers, depending on the expression levels of transporters.

CONCLUSION AND IMPLICATIONS

Silencing ABCC1, ABCC4 or ABCG2 expression alters accumulation of atorvastatin in myotubes, whereas the effect of silencing influx transporters depends on the expression of these transporters.

Advancing Alzheimer's disease pharmacotherapy: efficacy of glucocorticoid modulation with dazucorilant (CORT113176) in preclinical mouse models

BACKGROUND AND PURPOSE

Exposure to chronic stress and high levels of glucocorticoid hormones in adulthood has been associated with cognitive deficits and increased risk of Alzheimer's disease (AD). Dazucorilant has recently emerged as a selective glucocorticoid receptor (NR3C1) modulator, exhibiting efficacy in counteracting amyloid-β toxicity in an acute model of AD. We aim to assess the therapeutic potential of dazucorilant in reversing amyloid and tau pathologies through the inhibition of glucocorticoid receptor pathological activity, and providing additional evidence for its consideration in AD treatment.

EXPERIMENTAL APPROACH

The efficacy of dazucorilant was evaluated in two transgenic mouse models of amyloid pathology. The slowly progressing J20 and the aggressively pathological 5xFAD mice. Behavioural analysis was conducted to evaluate welfare, cognitive performances and anxiety levels. The activity of the glucocorticoid receptor system, neuroinflammation, amyloid burden and tau phosphorylation were examined in hippocampi.

KEY RESULTS

In both AD models, chronic treatment with dazucorilant improved working and long-term spatial memories along with the inhibition of glucocorticoid receptor-dependent pathogenic processes and the normalization of plasma glucocorticoid levels. Dazucorilant treatment also resulted in a reduction in tau hyperphosphorylation and amyloid production and aggregation. Additionally, dazucorilant seemed to mediate a specific re-localization of activated glial cells onto amyloid plaques in J20 mice, suggesting a restoration of physiological neuroinflammatory processes.

CONCLUSION AND IMPLICATIONS

Dazucorilant exhibited sustained disease-modifying effects in two AD models. Given that this compound has demonstrated safety and tolerability in human subjects, our results provide pre-clinical support for conducting clinical trials to evaluate its potential in AD.

MC16 promotes mitochondrial biogenesis and ameliorates acute and diabetic nephropathy

BACKGROUND AND PURPOSE

Kidney disease (KD) is a leading cause of mortality worldwide, affecting 〉10% of the global population. Two of the most common causes of KD are diabetes and acute kidney injury (AKI), both of which induce mitochondrial dysfunction resulting in renal proximal tubular damage/necrosis. Thus, pharmacological induction of mitochondrial biogenesis (MB) may provide a therapeutic strategy to block the onset/progression of KD. Here, we evaluated the pharmacological and potential therapeutic effects of a novel MB-inducing oxindole agent, MC16.

EXPERIMENTAL APPROACH

Primary cultures of rabbit renal proximal tubule cells (RPTCs) were used to evaluate the cellular signalling and MB-inducing effects of MC16. Mice were used to determine the MB-inducing effects of MC16 in vivo, and the metabolic effects of MC16 on the renal cortical metabolome. Mouse models of AKI and diabetic kidney disease (DKD) were used to demonstrate the therapeutic potential of MC16 to ameliorate acute and diabetic nephropathy.

KEY RESULTS

MC16 activated the PI3K-AKT-eNOS-FOXO1 axis and induced MB in RPTCs. MC16 induced MB and altered the renal cortical metabolome of mice. MC16 accelerated renal recovery, reduced vascular permeability, and diminished mitochondrial dysfunction following AKI. MC16 decreased diabetes-induced renal swelling, improved renal and mitochondrial function, and diminished interstitial fibrosis in DKD mouse models.

CONCLUSION AND IMPLICATIONS

MC16 is a novel compound that induces MB and ameliorates acute and diabetic nephropathy in mice. This study underscores that targeting MB following the onset of renal/metabolic insults may provide a therapeutic strategy to mitigate the onset and/or progression of KD.

Fatty acid binding protein 3 activates endothelial adhesion of circulating monocytes and impairs endothelial angiogenesis

BACKGROUND AND PURPOSE

Vascular inflammation and endothelial dysfunction cause the development of atherosclerotic cardiovascular diseases including coronary artery disease (CAD). While elevated fatty acid binding protein 3 (FABP3) may be associated with the presence of cardiovascular diseases, its mechanistic effects remain unclear. This study aimed to investigate the role of FABP3 in impaired angiogenesis and the development of atherosclerosis in CAD.

EXPERIMENTAL APPROACH

In total, 1104 patients were enrolled in a clinical observational study and the correlation between serum FABP3 and cardiovascular events were analysed. Another group of CAD patients and non-CAD subjects were enrolled, and their plasma FABP3 concentrations were measured. Primary cultured mononuclear cells endothelial progenitor cells and human coronary artery endothelial cells were used in vitro. Matrigel plug neovascularisation assay and the aortic ring assay were used in wild-type and apolipoprotein E-knockout mice in vivo.

KEY RESULTS

Circulating FABP3 was up-regulated in the cardiovascular event-positive group and in the CAD patients. Mononuclear cells from the CAD patients presented increased expression of FABP3. FABP3 enhanced the expression of adhesion molecules, including integrin β2, integrin α4 and PSGL1 in mononuclear cells. FABP3 caused endothelial cell dysfunction through the ERK/p38/STAT1/VEGF signalling pathway. Moreover, oxLDL or TNF-α stimulations impaired endothelial cell function through FABP3-dependent signalling pathways. FABP3 also impaired in vivo angiogenesis.

CONCLUSION AND IMPLICATIONS

This study elucidates the clinical and pathological impact of FABP3 on atherosclerotic CAD. Future research may be necessary to evaluate whether FABP3 could be a therapeutic target, especially with regard to stable CAD.

Discovery of a potent inhibitor of chaperone-mediated autophagy that targets the HSC70-LAMP2A interaction in non-small cell lung cancer cells

BACKGROUND AND PURPOSE

Chaperone-mediated autophagy (CMA) is a selective type of autophagy targeting protein degradation and maintains high activity in many malignancies. Inhibition of the combination of HSC70 and LAMP2A can potently block CMA. At present, knockdown of LAMP2A remains the most specific method for inhibiting CMA and chemical inhibitors against CMA have not yet been discovered.

EXPERIMENTAL APPROACH

Levels of CMA in non-small cell lung cancer (NSCLC) tissue samples were confirmed by tyramide signal amplification dual immunofluorescence assay. High-content screening was performed based on CMA activity, to identify potential inhibitors of CMA. Inhibitor targets were determined by drug affinity responsive target stability-mass spectrum and confirmed by protein mass spectrometry. CMA was inhibited and activated to elucidate the molecular mechanism of the CMA inhibitor.

KEY RESULTS

Suppression of interactions between HSC70 and LAMP2A blocked CMA in NSCLC, restraining tumour growth. Polyphyllin D (PPD) was identified as a targeted CMA small-molecule inhibitor through disrupting HSC70-LAMP2A interactions. The binding sites for PPD were E129 and T278 at the nucleotide-binding domain of HSC70 and C-terminal of LAMP2A, respectively. PPD accelerated unfolded protein generation to induce reactive oxygen species (ROS) accumulation by inhibiting HSC70-LAMP2A-eIF2α signalling axis. Also, PPD prevented regulatory compensation of macroautophagy induced by CMA inhibition via blocking the STX17-SNAP29-VAMP8 signalling axis.

CONCLUSIONS AND IMPLICATIONS

PPD is a targeted CMA inhibitor that blocked both HSC70-LAMP2A interactions and LAMP2A homo-multimerization. CMA suppression without increasing the regulatory compensation from macroautophagy is a good strategy for NSCLC therapy.

LINKED ARTICLES

This article is part of a themed issue Natural Products and Cancer: From Drug Discovery to Prevention and Therapy. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.10/issuetoc.

7 I, a structurally modified sinomenine, exerts dual anti-GBM effects by inhibiting glioblastoma proliferation and inducing necroptosis which further mediates lysosomal cell death

BACKGROUND AND PURPOSE

Glioblastoma multiforme (GBM) is an aggressive brain tumour which drug treatment has no overall significant effect on survival rate. Sinomenine is a natural product extracted from the traditional Chinese medicine Qingteng and was found to have a certain anti-tumour effect. Although, its short biological half-life, unstable physicochemical properties, large dosage and causes histamine release have hindered its use but it may form the basis for novel drug therapy of GBM.

EXPERIMENTAL APPROACH

We designed, synthesised and screened sinomenine derivative-7 I with high anti-GBM activity and investigated its mechanism of action. Its actions on GBM cells were detected by cell viability assay, RNA-Seq, Western blot, transmission electron microscopy, immunofluorescence along with other methods described.

KEY RESULTS

7 I exerted anti-GBM effects through a dual mechanism. 7 I arrested the cell cycle of GBM cells at the G2/M phase by the activation of the P53/P21/CDK1/cyclin B pathway, inhibiting GBM cells proliferation. Secondly, 7 I induced necroptosis of GBM cells through the classical RIPK1/RIPK3/MLKL-dependent pathway causing lysosomal damage and membrane permeabilization leading to lysosomal-mediated cell death. Finally, in vivo xenograft experiments, 7 I significantly inhibited the growth of glioblastoma, effectively reducing inflammation in mice and showing good safety profile.

CONCLUSIONS AND IMPLICATIONS

7 I, a structurally modified sinomenine, has excellent in vitro and in vivo anti-GBM activity and exerts dual anti-GBM effects by inhibiting glioblastoma proliferation and inducing necroptosis, which further mediates lysosomal cell death. In summary, 7 I is a promising candidate agent for GBM treatment.

LINKED ARTICLES

This article is part of a themed issue Natural Products and Cancer: From Drug Discovery to Prevention and Therapy. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.10/issuetoc.

Colon-targeted complement C5a1 receptor inhibition using pH-sensitive nanoparticles ameliorates experimental colitis

BACKGROUND AND PURPOSE

The complement system is associated with inflammatory bowel disease (IBD) pathology. Complement activation induces C5a production, which signals through the C5a1 receptor (C5aR1) to drive inflammatory responses that may underlie IBD.

EXPERIMENTAL APPROACH

We examined mucosal biopsies from ulcerative colitis patients and identified C5a1 receptor up-regulated in active lesions, supporting the C5a1 receptor as a target for therapeutic intervention. Cyclic peptide C5a1 receptor antagonists such as PMX205 are orally efficacious in preclinical colitis models; however, their clinical application may be limited by rapid metabolism. We therefore encapsulated PMX205 within pH-sensitive polymers to target drug for colon delivery following oral administration.

KEY RESULTS

PMX205 nanoparticles were non-toxic and released bioactive PMX205 in simulated colon fluid. In vivo imaging of Cy5-labelled nanoparticles demonstrated rapid entry and persistence in the mouse colon for up to 48 h. Next, we utilised the dextran sodium sulphate-induced colitis model to examine efficacy of the C5a1 receptor-antagonist formulation. We show that oral administration of PMX205 nanoparticles every 2 days from symptom onset significantly mitigated weight loss, clinical illness, colon length reduction and epithelial damage to a similar degree as C5a1 receptor-/- mice. Notably, unformulated PMX205 was markedly less effective in this dosing regimen.

CONCLUSION AND IMPLICATIONS

This novel colon-targeted formulation therefore offers a potent therapeutic strategy for translating C5a1 receptor antagonists for IBD conditions such as ulcerative colitis.

FGF1ΔHBS ameliorates DSS-induced ulcerative colitis by reducing neutrophil recruitment through the MAPK pathway

BACKGROUND AND PURPOSE

Inflammatory bowel diseases (IBDs) constitute chronic inflammatory disease of the gastrointestinal tract, with escalating global prevalence. There is a pressing demand for safe and effective treatments for IBDs. Fibroblast growth factor 1 (FGF1) variant FGF1ΔHBS, characterised by reduced mitogenic capacity, has shown promising therapeutic potential in various inflammatory conditions, including obesity and diabetic nephropathy. Hence, exploring the therapeutic impact of FGF1ΔHBS on colitis is warranted.

EXPERIMENTAL APPROACH

The protective role of FGF1ΔHBS was evaluated using a dextran sulphate sodium (DSS)-induced colitis model in mice. RNA-seq analysis was performed on colonic tissues. Inflammatory factor expression was examined by quantitative real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay. Flow cytometry and immunofluorescence staining were employed to confirm the inhibitory effect of FGF1ΔHBS on neutrophil recruitment. Western blotting was performed to explore the mitogen-activated protein kinase (MAPK) signalling pathway.

KEY RESULTS

FGF1ΔHBS significantly alleviated DSS-induced colitis, as indicated by reduced Disease Activity Index scores and less histological injury to the colon. Additionally, FGF1ΔHBS decreased the expression of pro-inflammatory factors. Mechanistically, FGF1ΔHBS inhibited neutrophil-associated chemokine expression in intestinal epithelial cells by suppressing the MAPK signalling pathway, thereby reducing neutrophil recruitment and attenuating neutrophil-mediated intestinal inflammation.

CONCLUSION AND IMPLICATIONS

FGF1ΔHBS protects against DSS-induced colitis in mice by inhibiting neutrophil recruitment through MAPK activity suppression, suggesting a potential therapeutic strategy for preventing IBDs.

GL-V9 inhibits Caspase-11 activation-induced pyroptosis by suppressing ALOX12-mediated lipid peroxidation to alleviate sepsis

BACKGROUND AND PURPOSE

Sepsis, caused by pathogen infection, poses a serious threat to human life. While the link between sepsis and pyroptosis via Caspase-11 non-canonical inflammasome activation is known, effective treatments remain lacking. Previous studies have confirmed that GL-V9 has antifibrotic and antitumor activities, but whether it has a therapeutic effect on sepsis is unclear. The aim of this study was to investigate the anti-inflammatory activity of GL-V9 and its possible mechanism.

EXPERIMENTAL APPROACH

The caecal ligation and puncture (CLP) model was used to assess the antiseptic effects of GL-V9 in vivo. Mouse bone marrow derived macrophages (BMDMs) and murine macrophages line J774A.1 also served as an in vitro Caspase-11 activation induced pyroptosis model. Cellular functions and molecular mechanism were analysed using cell viability assay, PI uptake assay, western blotting, immunofluorescence and co-immunoprecipitation.

KEY RESULTS

GL-V9 reduced tissue damage and mortality in mice with sepsis, and decreased the secretion of inflammatory factors in vivo. In vitro, GL-V9 suppressed Caspase-11-induced pyroptosis and prevented the release of LPS from early endosomes. Mechanistic studies revealed that GL-V9 limits Caspase-11 activation by inhibiting ALOX12-mediated lipid peroxidation. Further studies confirmed that GL-V9 did not further alleviate the symptoms and inflammatory response of septic mice in Alox12 deficient mice.

CONCLUSION AND IMPLICATIONS

GL-V9 exerts a powerful anti-sepsis effect in vivo, which is associated with the inhibition of Caspase-11 activation. Mechanistically, GL-V9 may block LPS release from early endosomes by inhibiting ALOX12-mediated lipid peroxidation. This suggests that GL-V9 is a potential candidate for the treatment of sepsis.

Role for the liver X receptor agonist 22-ketositosterol in preventing disease progression in an Alzheimer's disease mouse model

BACKGROUND AND PURPOSE

Liver X receptors (LXRs) are promising therapeutic targets for alleviating Alzheimer's disease (AD) symptoms. We assessed the impact of the semi-synthetic LXR agonist 22-ketositosterol on disease progression in an AD mouse model.

EXPERIMENTAL APPROACH

From 5.5 months of age, APPswePS1ΔE9 (AD) mice and wild-type (WT) littermates received a regular or 22-ketositosterol-supplemented diet (0.017% w/w). Cognition was assessed with object location and recognition tasks and a spontaneous alternation Y-maze test. Amyloid β was quantified using immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA), microglia (Iba1, CD68) and astrocyte (GFAP) markers using IHC. Sterols were determined in food, serum, liver and cerebellum.

KEY RESULTS

22-Ketositosterol activated both liver X receptors-α and -β and promoted cholesterol efflux in cell cultures. Diet supplementation with 22-ketositosterol prevented a decline in the performance of APPswePS1ΔE9 mice in the object location task but not in the other two tasks. Without affecting amyloid β deposition, 22-ketositosterol decreased microglia (Iba1, CD68) and astrocyte (GFAP) markers in the cortex and hippocampus of APPswePS1ΔE9, suggesting potential anti-inflammatory effects. No lipid accumulation was detected in the liver or serum upon 22-ketositosterol supplementation.

CONCLUSIONS AND IMPLICATIONS

Diet supplementation with 22-ketositosterol prevented the decline in spatial memory of APPswePS1ΔE9 mice. Our data suggest therapeutic benefits of 22-ketositosterol possibly by enhancing cholesterol efflux and mitigating inflammatory responses, without inducing hepatosteatosis or hypertriglyceridemia.

Hydroxychloroquine cures autoimmune myocarditis by inhibiting the innate immune system via the C-X-C motif chemokine ligand 16 and C-X-C motif receptor 6 axis between macrophages and T cells

BACKGROUND AND PURPOSE

Myocarditis is a life-threatening inflammatory disease, but lacks effective treatment options. Hydroxychloroquine (HCQ), an established antimalarial agent, is used widely to manage rheumatic disorders. This research aimed to evaluate the efficacy of HCQ in treating myocarditis.

EXPERIMENTAL APPROACH

A mouse model of experimental autoimmune myocarditis (EAM) was used to evaluate the therapeutic effects of HCQ on cardiac function, inflammation and fibrosis. Echocardiography, histology and cytokine assays were performed to assess cardiac function and inflammatory responses. Single-cell RNA sequencing was employed to analyse immune cell populations and chemotactic activity. C-X-C motif chemokine ligand 16 (CXCL16) levels were measured in cardiac tissue and serum, while YY1 expression was measured by western blotting in macrophages and cardiac tissue. Flow cytometry was used to evaluate immune cell infiltration and migration.

KEY RESULTS

HCQ improved cardiac function in acute and chronic myocarditis. HCQ treatment reduced inflammation, fibrosis and immune cell infiltration in myocarditis models. Single-cell RNA sequencing revealed that HCQ lowered inflammatory cell proportions and suppressed macrophage chemotaxis. HCQ reduced YY1 levels, leading to the down-regulation of CXCL16 expression in macrophages and inhibition of CXCL16-mediated chemotaxis to Th17 and natural killer T (NKT) cells. CXCL16 neutralizing antibodies improved cardiac function and reduced inflammation in myocarditis.

CONCLUSION AND IMPLICATIONS

HCQ improves cardiac function and reduces inflammation in myocarditis by inhibiting CXCL16 expression in macrophages, by suppressing its transcription factor YY1, which in turn reduced the chemotaxis of Th17 and NKT cells. HCQ is a promising therapeutic agent for myocarditis.

Inhibition of sphingosine-1-phosphate receptor-2 attenuates idiopathic pulmonary fibrosis by preventing its binding to dapper1 in bronchial epithelial cells

BACKGROUND AND PURPOSE

Activation of the sphingosine-1-phosphate receptor-2 (S1P2 receptor) promotes idiopathic pulmonary fibrosis (IPF). However, the mechanisms associated with IPF development via S1P2 receptor signalling are poorly understood and no S1P2 receptor antagonists have been approved for clinical use.

EXPERIMENTAL APPROACH

Western blotting and immunohistochemical assays analysed inflammatory factors and epithelial-mesenchymal transition (EMT) markers. Co-immunoprecipitation and immunofluorescence analysed the binding of S1P2 receptor to dapper1 (Dpr1) and cyclic AMP response-binding protein 1 (CREB1). X-ray-based computed tomography diagnosed IPF in bleomycin (BLM)-treated mice. Barometric whole-body plethysmography tested pulmonary function of mice. Masson's trichrome and Sirius red staining analysed extracellular matrix deposition. Enzyme-linked immunosorbent assays analysed inflammatory factors and hydroxyproline.

KEY RESULTS

Activation of S1P2 receptors promoted IPF through the binding of S1P2 receptor to Dpr1, decreasing dishevelled (Dvl) degradation to accumulate β-catenin. The β-catenin accumulated in the nucleus, upregulating its target genes by binding to T-cell factor/lymphoid enhancer factor. The binding of S1P2 receptor to Dpr1 also led to S1P2 receptor translocation to the nucleus, where it promoted EMT by activating CREB1. BLM-induced IPF in mice was characterised by activated-S1P2 receptor signalling. Inhibition of S1P2 receptor prevented the binding of S1P2 receptor to Dpr1, resulting in decreased β-catenin accumulation and blocking nuclear translocation of S1P2 receptor. The S1P2 receptor antagonist S118 was more effective than pirfenidone in attenuating IPF through anti-inflammatory, anti-fibrosis, and anti-EMT effects.

CONCLUSIONS AND IMPLICATIONS

Activation of S1P2 receptors promotes IPF through the binding of S1P2 receptor to Dpr1 and the nuclear translocation of S1P2 receptor to activate CREB1. Thus, the S1P2 receptor antagonist S118 has potential clinical application in attenuating IPF.

Vitamin D deficiency induces erectile dysfunction: Role of superoxide and Slpi

BACKGROUND AND PURPOSE

Epidemiological studies suggest a relationship between vitamin D deficiency and erectile dysfunction (ED). We hypothesized that vitamin D deficiency or vitamin D receptor (VDR) knockout causes ED and analysed the underlying molecular mechanisms.

EXPERIMENTAL APPROACH

Erectile function was assessed in vivo in anaesthetized male mice or rats by evaluating intracavernosal pressure (ICP) and in vitro in male Vdr-/- mice, and rat or human isolated corpora cavernosa (CCs) mounted in a myograph. Bulk RNA-sequencing (RNA-seq) transcriptomic analysis was performed in rat CCs. Vitamin D deficiency was induced in rats fed a vitamin D-free diet for 5 months.

KEY RESULTS

CCs from human donors with low plasma vitamin D exhibited reduced nitric oxide (NO)-dependent erectile function. This ED was also reproduced in vitamin D-deficient rats and VDR knockout mice, in vivo and ex vivo, and is associated with penile fibrosis and reduced response to the phosphodiesterase 5 inhibitor (PDE5i) sildenafil. CCs from deficient rats show increased superoxide levels, and their impaired erectile function was restored by superoxide scavengers. Transcriptomic analysis, real-time polymerase chain reaction (RT-PCR) and Western blot showed down-regulated secretory leukocyte protease inhibitor (Slpi). Moreover, recombinant SLPI prevented superoxide-induced ED, while Slpi gene silencing led to reduced erectile function in a superoxide-dependent manner.

CONCLUSION AND IMPLICATIONS

Vitamin D deficiency or VDR knockout reduces erectile function. We suggest that this effect is mediated by increased superoxide levels and down-regulation of SLPI. Vitamin D deficiency might be an aetiological factor for vascular ED and for the therapeutic failure of PDE5i.

Berberine partially ameliorates cardiolipotoxicity in diabetic cardiomyopathy by modulating SIRT3-mediated lipophagy to remodel lipid droplets homeostasis

BACKGROUND AND PURPOSE

Emerging evidence indicated that the excessive lipid droplets (LDs) accumulation and lipotoxicity play a significant role in the development of diabetic cardiomyopathy (DCM), yet the regulatory mechanisms governing the function of cardiac LDs are still unknown. Lipophagy has been shown to be involved in the maintenance of LDs homeostasis. The objective of this study was to explore the mechanism of lipophagy in cardiomyocytes and investigate whether berberine could mitigate DCM by modulating this pathway.

EXPERIMENTAL APPROACH

Bioinformatics analysis identified disorders of lipid metabolism and autophagy in DCM. To carry out further research, db/db mice were utilized. Furthermore, H9C2 cells treated with palmitic acid were employed as a model to explore the molecular mechanisms involved in myocardial lipotoxicity.

KEY RESULTS

The results showed that lipophagy was impaired in DCM. Mechanistically, sirtuin 3 (SIRT3) was demonstrated to regulate lipophagy in cardiomyocytes. SIRT3 was down-regulated in DCM. Conversely, activation of SIRT3 by the activator nicotinamide riboside (NR) could promote lipophagy to alleviate PA-induced lipotoxicity in H9C2 cells. Moreover, berberine administration markedly mitigated diabetes-induced cardiac dysfunction and hypertrophy in db/db mice, which dependent on SIRT3-mediated lipophagy.

CONCLUSION AND IMPLICATIONS

Collectively, SIRT3 could moderate cardiac lipotoxicity in DCM by promoting lipophagy, suggesting that the regulation of SIRT3-mediated lipophagy may be a promising strategy for treating DCM. The findings indicate that the therapeutic potential of berberine for DCM is associated with lipophagy.

Ventral pallidum GABAergic and glutamatergic neurons modulate arousal during sevoflurane general anaesthesia in male mice

BACKGROUND AND PURPOSE

The induction and emergence of general anaesthesia involve an altered process of states of consciousness, yet the central nervous system mechanisms remain inadequately understood. The ventral pallidum (VP) within the basal ganglia is crucial in sleep-wake modulation. However, its involvement in general anaesthesia and the underlying neuronal mechanisms are not well elucidated.

EXPERIMENTAL APPROACH

In vivo electrophysiological recordings were conducted to examine changes in the activity of different types of VP neurons before and after sevoflurane exposure. Fibre photometry, combined with electroencephalogram and electromyography recordings, was employed to analyse neuronal activity during both the induction and recovery phases of sevoflurane anaesthesia. Chemogenetics was implemented to investigate the impact of modulated neuronal activity on anaesthesia induction and emergence, whereas optogenetics was used for real time activation of neurons at different depths of anaesthesia.

KEY RESULTS

Sevoflurane exposure reduced the firing activity of both VP GABAergic (VPGABA) and VP glutamatergic (VPglu) neurons, without affecting cholinergic neurons. VPGABA and VPglu neuronal activity decreased during sevoflurane anaesthesia induction and increased during emergence. Manipulation of VPGABA neurons bidirectionally influenced the duration of induction and emergence. Inhibiting VPglu neurons accelerated induction. Real time activation of VPGABA neurons triggered cortical activation and behavioural emergence during steady-state sevoflurane anaesthesia and reduced the burst suppression ratio during deep anaesthesia.

CONCLUSION AND IMPLICATIONS

These findings highlight the role of VPGABA and VPglu neurons in modulating transitions between anaesthesia stages, providing valuable insights into the neuronal mechanisms underlying sevoflurane-induced anaesthesia.

Inhibition of DNA polymerase eta-mediated translesion DNA synthesis with small molecule sensitises ovarian cancer stem-like cells to chemotherapy

BACKGROUND AND PURPOSE

Chemoresistance and tumour relapse pose significant challenges in achieving successful chemotherapy outcomes. Targeting DNA polymerase eta (Pol ƞ)-mediated mutagenic translesion DNA synthesis (TLS) has emerged as a promising strategy for improving chemotherapy. However, the identification of small molecule inhibitors targeting Pol ƞ -mediated TLS with high in vivo efficacy remains a challenge.

EXPERIMENTAL APPROACH

The small molecule was identified through in silico screening. Pol η inhibitory potential of the identified small molecule was validated by a fluorescent-based reporter strand displacement assay. Flow cytometry was conducted to analyse the CD44 + CD117 + cancer stem-like cell (CSC) population and live-dead cell population. Xenograft mouse models were used to test the CSC sensitising potential.

KEY RESULTS

We screened and identified chrysin as a small-molecule inhibitor that sensitises ovarian cancer stem-like cells to cisplatin treatment by inhibiting Pol ƞ -mediated TLS. Chrysin effectively inhibits Pol ƞ expression, mitigates cancer stem-like cell enrichment and enhances cisplatin-induced cell death both in vitro and in vivo. Furthermore, chrysin treatment reduces spontaneous and cisplatin-induced mutagenesis. Pre-treatment with chrysin attenuates cisplatin-induced haematological toxicity and suppresses tumour growth in human ovarian cancer xenografts.

CONCLUSIONS AND IMPLICATIONS

These results establish chrysin as a novel class of TLS inhibitors and highlight its potential as a chemotherapy adjuvant for overcoming chemoresistance and improving treatment outcomes in ovarian cancer.

Genetic deficiency or pharmacological inhibition of cGAS-STING signalling suppresses kidney inflammation and fibrosis

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) is characterised by inflammation, which can lead to tubular atrophy and fibrosis. The molecular mechanisms are not well understood. In this study, we investigated the functional role of the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signalling in renal inflammation and fibrosis.

EXPERIMENTAL APPROACH

Mice with global cGAS deficiency or global or myeloid cell-specific STING deficiency or wild-type mice treated with RU.521, a selective cGAS inhibitor, were used to examine the role of cGAS-STING signalling in renal inflammation and fibrosis in a preclinical model of obstructive nephropathy in vivo. Bone marrow-derived macrophages were used to determine whether tubular epithelial cell-derived DNA can activate cGAS-STING signalling in vitro.

KEY RESULTS

Following obstructive injury, cGAS-STING signalling was activated in the kidneys during the development of renal fibrosis. Mice with deficiency of cGAS or STING exhibited significantly less macrophage proinflammatory activation, myofibroblast formation, total collagen deposition, and extracellular matrix (ECM) protein production in the kidneys following obstructive injury. Pharmacological inhibition of cGAS with RU.521 reduced macrophage proinflammatory activation, suppressed myofibroblast formation, and attenuated kidney fibrosis following obstructive injury. Mechanistically, cGAS-STING signalling in macrophages is activated by double-stranded DNA released from damaged tubular epithelial cells, which induces inflammatory responses.

CONCLUSIONS AND IMPLICATIONS

Our study identifies the cGAS-STING signalling pathway as a critical regulator of macrophage proinflammatory activation during the development of renal fibrosis. Therefore, inhibition of cGAS-STING signalling may represent a novel therapeutic strategy for CKD.

Cordycepin ameliorates autoimmunity by promoting STING degradation via autophagy pathway

BACKGROUND AND PURPOSE

Stimulator of interferon response cGAMP interactor 1 (STING), a central hub protein of cyclic GMP-AMP synthase (cGAS)-STING signalling pathway, has a crucial role in regulating type I interferons (IFNs) production and response. Recent studies indicate that excessive activation of STING is strongly associated with autoimmune diseases, including systemic lupus erythematosus (SLE). Searching immunomodulators that negatively regulate STING might greatly contribute to the suppression of autoimmunity.

EXPERIMENTAL APPROACH

The peripheral blood mononuclear cells (PBMCs) of SLE patients, Hela cells, L929 cells and bone marrow-derived macrophages (BMDMs) from mice were used as in vitro models. While, Trex1 KO mouse autoimmune disease model was used as in vivo model. After treatment with cordycepin, a nucleoside from Cordyceps mushrooms, type I IFNs production and response were determined by western blotting, real-time polymerase chain reaction (PCR), dual-luciferase assay, enzyme-linked immunosorbent assay (ELISA), haematoxylin-eosin staining and RNA-seq.

KEY RESULTS

Cordycepin inhibited type I IFNs production and response in human and murine systems following cGAS-STING signalling activation. Importantly, cordycepin markedly attenuates the autoinflammatory and autoimmune responses in Trex1 KO BMDMs and Trex1 KO mice. Furthermore, cordycepin effectively suppressed the production of type I IFNs and interferon-stimulated genes (ISGs) in the PBMCs of SLE patients. Mechanistically, cordycepin promoted STING degradation via autophagy pathway upon DNA stimulation.

CONCLUSION AND IMPLICATIONS

This study shows that cordycepin promotes STING autophagic degradation to alleviate autoimmunity upon DNA stimulation. Cordycepin might be a potential therapeutic candidate for alleviating aberrant type I IFNs in autoimmune and autoinflammatory diseases.

SGK3 promotes estrogen receptor-positive breast cancer proliferation by activating STAT3/ZMIZ2 pathway to stabilise β-catenin

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.

Baclofen modulates the immune response after spinal cord injury with locomotor benefits

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.

Pharmacological profiling of small molecule modulators of the TMEM16A channel and their implications for the control of artery and capillary function

BACKGROUND AND PURPOSE

TMEM16A chloride channels constitute a depolarising mechanism in arterial smooth muscle cells (SMCs) and contractile cerebral pericytes. TMEM16A pharmacology is incompletely defined. We elucidated the mode of action and selectivity of a recently identified positive allosteric modulator of TMEM16A (PAM_16A) and of a range of TMEM16A inhibitors. We also explore the consequences of selective modulation of TMEM16A activity on arterial and capillary function.

EXPERIMENTAL APPROACH

Patch-clamp electrophysiology, isometric tension recordings, live imaging of cerebral cortical capillaries and assessment of cell death were employed to explore the effect of selective pharmacological control of TMEM16A on vascular function.

KEY RESULTS

In low intracellular free Ca2+ concentrations ([Ca2+]i), nanomolar concentrations of PAM_16A activated heterologous TMEM16A channels, while being almost ineffective on the closely related TMEM16B channel. In either the absence of Ca2+ or in saturating [Ca2+]i, PAM_16A had no effect on TMEM16A currents at physiological potentials. PAM_16A selectively activated TMEM16A currents in SMCs and enhanced aortic contraction caused by phenylephrine or angiotensin-II and capillary (pericyte) constriction evoked by endothelin-1 or oxygen-glucose deprivation (OGD) to simulate cerebral ischaemia. Conversely, selective TMEM16A inhibition with Ani9 facilitated aortic, mesenteric and pericyte relaxation, and protected against OGD-mediated pericyte cell death. Unlike PAM_16A and Ani9, a range of other available modulators were found to interfere with endogenous cationic currents in SMCs.

CONCLUSIONS AND IMPLICATIONS

Arterial tone and capillary diameter can be controlled with TMEM16A modulators, highlighting TMEM16A as a target for disorders with a vascular component, including hypertension, stroke, Alzheimer's disease and vascular dementia.

Chronic stress induces behavioural changes through increased kynurenic acid by downregulation of kynurenine-3-monooxygenase with microglial decline

BACKGROUND AND PURPOSE

Alterations in tryptophan-kynurenine (TRP-KYN) pathway are implicated in major depressive disorder (MDD). α7 nicotinic acetylcholine (α7nACh) receptor regulates the hypothalamic-pituitary-adrenal (HPA) axis. We have shown that deficiency of kynurenine 3-monooxygenase (KMO) induces depression-like behaviour via kynurenic acid (KYNA; α7nACh antagonist). In this study, we investigated the involvement of the TRP-KYN pathway in stress-induced behavioural changes and the regulation of the HPA axis.

EXPERIMENTAL APPROACH

Mice were exposed to chronic unpredictable mild stress (CUMS) and subjected to behavioural tests. We measured TRP-KYN metabolites and the expression of their enzymes in the hippocampus. KMO heterozygous mice were used to investigate stress vulnerability. We also evaluated the effect of nicotine (s.c.) on CUMS-induced behavioural changes and an increase in serum corticosterone (CORT) concentration.

KEY RESULTS

CUMS decreased social interaction time but increased immobility time under tail suspension associated with increased serum corticosterone concentration. CUMS increased KYNA levels via KMO suppression with microglial decline in the hippocampus. Kmo+/- mice were vulnerable to stress: they exhibited social impairment and increased serum corticosterone concentration even after short-term CUMS. Nicotine attenuated CUMS-induced behavioural changes and increased serum corticosterone concentration by inhibiting the increase in corticotropin-releasing hormone. Methyllycaconitine (α7nACh antagonist) inhibited the attenuating effect of nicotine.

CONCLUSIONS AND IMPLICATIONS

CUMS-induced behavioural changes and the HPA axis dysregulation could be induced by the increased levels of KYNA via KMO suppression. KYNA plays an important role in the pathophysiology of MDD as an α7nACh antagonist. Therefore, α7nACh receptor is an attractive therapeutic target for MDD.

Activating transcription factor-3 orchestrates the modulation of vascular anti-contractile activity and relaxation by governing the secretion of HDL-bound sphingosine-1-phosphate in perivascular adipose tissue

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.

Inhibition of the upregulated phosphodiesterase 4D isoforms improves SERCA2a function in diabetic cardiomyopathy

BACKGROUND AND PURPOSE

Sarcoplasmic reticulum Ca2+-ATPase (SERCA2a) is impaired in heart failure. Phosphodiesterases (PDEs) are implicated in the modulation of local cAMP signals and protein kinase A (PKA) activity essential for cardiac function. We characterise PDE isoforms that underlie decreased activities of SERCA2a and reduced cardiac contractile function in diabetic cardiomyopathy.

EXPERIMENTAL APPROACH

Wild type mice were fed with either normal chow or a high-fat diet (HFD). Cardiomyocytes were isolated for excitation-contraction coupling (ECC), fluorescence resonant energy transfer PKA biosensor and proximity ligation assays.

KEY RESULTS

The upregulated PDE4D3 and PDE4D9 isoforms in HFD cardiomyocytes specifically bound to SERCA2a but not ryanodine receptor 2 (RyR2) on the sarcoplasmic reticulum (SR). The increased association of PDE4D isoforms with SERCA2a in HFD cardiomyocytes led to reduced local PKA activities and phosphorylation of phospholamban (PLB) but minimally effected the PKA activities and phosphorylation of RyR2. These changes correlate with slower calcium decay tau in the SR and attenuation of ECC in HFD cardiomyocytes. Selective inhibition of PDE4D3 or PDE4D9 restored PKA activities and phosphorylation of PLB at the SERCA2a complex, recovered calcium decay tau, and increased ECC in HFD cardiomyocytes. Therapies with PDE4 inhibitor roflumilast, PDE4D inhibitor BPN14770 or genetical deletion of PDE4D restored PKA phosphorylation of PLB and cardiac contractile function.

CONCLUSION AND IMPLICATIONS

The current study identifies upregulation of specific PDE4D isoforms that selectively inhibit SERCA2a function in HFD-induced cardiomyopathy, indicating that this remodelling can be targeted to restore cardiac contractility in diabetic cardiomyopathy.

Carbonic anhydrase IX inhibition as a path to treat neuroblastoma

BACKGROUND AND PURPOSE

Tumour hypoxia frequently presents a major challenge in the treatment of neuroblastoma (NBL). The neuroblastoma cells produce carbonic anhydrase IX (CA IX), an enzyme crucial for the survival of cancer cells in low-oxygen environments.

EXPERIMENTAL APPROACH

We designed and synthesised a novel high-affinity inhibitor of CA IX. The highest to-date. The affinities were determined for all human catalytically active CA isozymes showing significant selectivity for CA IX over other isozymes. The inhibitor effect on neuroblastoma cancer cell growth was determined in vitro and in vivo via a mice xenograft model.

KEY RESULTS

The novel designed inhibitor effectively mitigated the acidification induced by CA IX and reduced spheroid growth under hypoxic conditions in the SK-N-AS cell line. It also diminished the secretion of pro-tumour chemokines IL-8 (CXCL2) and CCL2. When we combined this novel CA IX inhibitor with a compound that inhibits the chemokine receptor CCR2 protein activity, we observed a reduction in mouse tumour growth. The combined treatment also prompted tumours to exhibit adaptive resistance by producing higher levels of vascular endothelial growth factor receptors (VEGFR) and other compensatory signals.

CONCLUSIONS AND IMPLICATIONS

This research underscores the pivotal role of CA IX in cancer and the potential of a novel CA IX inhibitor-based combination intervention therapy for neuroblastoma treatment.

Actions of dexmedetomidine in regulating NLRP3 in postoperative cognitive dysfunction in aged mice via the autophagy-lysosome pathway

BACKGROUND AND PURPOSE

Autophagy-lysosomal pathway dysfunction leads to postoperative cognitive dysfunction (POCD). Dexmedetomidine (Dex) improves POCD, and we probed the effects of Dex on autophagy-lysosomal pathway dysfunction in a POCD model.

EXPERIMENTAL APPROACH

A POCD mouse model was established and intraperitoneally injected with Dex. Cognitive function was evaluated by Morris water maze/open field test/novel object recognition assay. Levels of neurotransmitters/inflammatory cytokines in hippocampus, and NLRP3/ASC/Cleaved Caspase-1 proteins were determined by ELISA/Western blot. NLRP3 inflammasome-mediated microglial activation/astrocyte A1 differentiation in the hippocampal CA1 region were assessed by immunofluorescence assay. BV-2 cells were treated with lipopolysaccharide (LPS) and Dex and/or the NLRP3 inflammasome activator Nigericin, and transfected with si-TFEB for co-culture with primary reactive astrocytes (RAs) to verify the function of Dex in vitro.

KEY RESULTS

Dex alleviated cognitive dysfunction in POCD mice and repressed NLRP3 inflammasome-mediated microglial activation and astrocyte A1 differentiation. NLRP3 inflammasome activation partially reversed the protective effect of Dex on the POCD condition. In vitro experiments verified the inhibitory properties of Dex on microglial activation and astrocyte A1 differentiation. Dex induces TFEB nuclear translocation, microglial autophagy and lysosomal biogenesis. By activating the autophagy-lysosome pathway, Dex regulated NLRP3 inflammasome-mediated microglial activation, inhibited astrocyte A1 differentiation and alleviated POCD in vivo.

CONCLUSION AND IMPLICATIONS

Dex regulates NLRP3 inflammasome-mediated hippocampal microglial activation by promoting TFEB nuclear translocation and activating the autophagy-lysosome pathway and inhibits astrocyte A1 differentiation, thereby alleviating POCD.

Toll-like receptor 4 deficiency ameliorates experimental ileitis and enteric neuropathy: Involvement of nitrergic and 5-hydroxytryptaminergic neurotransmission

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-HT2A 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.

Atractylodes macrocephala Koidz polysaccharide ameliorates DSS-induced colitis in mice by regulating the gut microbiota and tryptophan metabolism

BACKGROUND AND PURPOSE

Ulcerative colitis (UC) is an idiopathic inflammatory bowel disease, and the range of current clinical treatments is not ideal. We previously found that polysaccharide of Atractylodes macrocephala Koidz (PAMK) is beneficial in DSS-induced colitis, and we aimed to investigate the underlying mechanisms in this study.

EXPERIMENTAL APPROACH

PAMK was used to treat DSS-induced colitis in mice, 16S rRNA sequencing analysis was used to detect changes in the intestinal microbiota, targeted metabolomics analysis was used to determine the content of tryptophan-metabolizing bacteria, and western blotting was used to determine aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) levels. Furthermore, antibiotic-mediated depletion of gut microbiota and faecal microbiota transplantation were performed to assess the role of the gut microbiota in PAMK alleviation of colitis.

KEY RESULTS

PAMK treatment relieved intestinal microbiota dysbiosis in mice with colitis, contributed to the proliferation of tryptophan-metabolizing bacteria, and increased the levels of tryptophan metabolites, resulting in a significant increase in the nuclear translocation of PXR and expression of PXR and its target genes, but not AhR. The gut microbiota is important in PAMK treatment of colitis, including in the alleviation of symptoms, inhibition of inflammation, maintenance of the integrity of the intestinal barrier, and the regulation of the Th17/Treg cell balance.

CONCLUSION AND IMPLICATIONS

Based on our findings, we elucidate a novel mechanism by which PAMK alleviates DSS-induced colitis and thus provides evidence to support the potential development of PAMK as a new clinical drug against UC.

GI-Y2, a novel gasdermin D inhibitor, attenuates sepsis-induced myocardial dysfunction by inhibiting gasdermin D-mediated pyroptosis in macrophages

BACKGROUND AND PURPOSE

Myocardial dysfunction is a significant complication associated with sepsis. However, there are currently no specific and effective treatments available. Inhibiting gasdermin D (GSDMD)-mediated pyroptosis has shown promise in mitigating sepsis-induced myocardial dysfunction. The GSDMD inhibitor Y2 (GI-Y2) has been demonstrated to directly bind to GSDMD. Nonetheless, it remains uncertain whether GI-Y2 offers a cardioprotective effect in the context of sepsis-induced myocardial dysfunction.

EXPERIMENTAL APPROACH

A mouse model of sepsis was created using lipopolysaccharide (LPS), caecal ligation and puncture. Following treatment with GI-Y2 or macrophage membrane-encapsulated GI-Y2 nanoparticles (GI-Y2@MM-NPs), myocardial dysfunction and pyroptosis levels in heart tissues were assessed. Transcriptome sequencing revealed the molecular mechanism of GI-Y2 in treating septic cardiomyopathy.

KEY RESULTS

We observed that GI-Y2 alleviated myocardial dysfunction and attenuated cardiac inflammation in mice induced by LPS, caecal ligation and puncture. GI-Y2 reduced macrophage pyroptosis and attenuated macrophage-mediated cardiomyocyte injury induced by LPS/nigericin. Concurrently, we confirmed the protective effect of GI-Y2 against LPS-induced cardiac dysfunction was abolished in the absence of GSDMD. Additionally, GI-Y2 attenuated the mitochondrial damage induced by LPS by inhibiting GSDMD in the mitochondria. Furthermore, we developed GI-Y2@MM-NPs to enhance the targeting capability of GI-Y2 towards macrophages in heart tissues and demonstrated its protective effect in vivo.

CONCLUSION AND IMPLICATIONS

These findings indicate that GI-Y2 alleviates septic myocardial injury and dysfunction by specifically targeting GSDMD, thereby inhibiting GSDMD-mediated pyroptosis and mitochondrial damage. Both GI-Y2 and GI-Y2@MM-NPs may serve as promising therapeutic options for addressing septic myocardial dysfunction.