ARRIVE 2.0 and the British Journal of Pharmacology: Updated guidance for 2020

Methodological limitations and confounders in dermal toxicity evaluation of aqueous test substance by OECD technical guidelines 402, 410: our experience of testing ethanol based hand sanitizer

BACKGROUND

In view of overzealous use of Alcohol based hand sanitizer (ABHS) during COVID-19 pandemic and associated alarming rise in the cases of hand eczema and dermatitis around the world. We conducted an in vivo dermal toxicity with objective of exploring the acute and subacute effects of ethanol based hand sanitizer (EBHS) on Sprague Dawley rats.

AIMS

To evaluate acute and subacute dermal toxicity due to ethanol based hand sanitizer (EBHS) on Sprague Dawley rats.

METHODS

In first phase, following Organisation for Economic Co-operation and Development (OECD) Technical Guidelines (TG) 402, we conducted acute dermal toxicity study with two rats and EBHS containing 72.34% ethanol. In second phase, sub-acute dermal toxicity study was conducted, following OECD TG 410 with five groups of rats (10 animals of either sexes in each group) at various doses.

RESULTS

In both the studies, no erythema, oedema, and eschar was observed. Although no clinical signs of toxicity were observed in both the studies, one death was encountered in subacute study. Macroscopically skin was normal; however, microscopic changes such as hyperkeratosis, parakeratosis, erosion, and extracellular oedema in epidermis and diffuse inflammatory cell infiltration in dermis was observed, suggestive of spongiotic dermatitis and 'clinic-pathological discordance'. However, attributing this changes to ethanol is difficult due to methodological limitations and confounders.

CONCLUSION

In both the studies, ethanol based hand sanitizer (EBHS) was found to be non-irritant with LD50 of > 2000 mg/kg and classified as Class 5/Unclassified according to GHS classification. Although, spongiotic changes were observed, methodological limitation of absence of control group in TG 402 and confounding effect of water and occlusion in all the animals/groups in both studies prevented us to attribute it to ethanol.

Salidroside attenuates the acquisition of morphine-induced conditioned place preference in mice via improving neurosynaptic plasticity in the ventral tegmental area

BACKGROUND AND PURPOSE

Rhodiola rosea has therapeutic effects in several neurological disease models and its ethanolic extract prevents the acquisition of morphine-induced conditioned place preference (CPP). We investigate the potential mechanism by which the active component of R. rosea attenuates the acquisition of morphine-induced CPP and explore its association with synaptic plasticity.

EXPERIMENTAL APPROACH

Using systematic network pharmacology, morphine-treated SH-SY5Y cells and cortical primary neurons, we identified the active component of R. rosea against morphine addiction in vitro. Morphine-induced CPP and additional behavioural tests were conducted after salidroside treatment. Synaptic function and structural plasticity changes in the ventral tegmental area (VTA) were characterised via immunofluorescence staining, fibre photometry and western blot. RNA sequencing, qPCR and western blotting were used to elucidate the mechanism of salidroside in attenuating the acquisition of morphine-induced CPP.

KEY RESULTS

We identified salidroside as the key active component, which reduced intracellular Ca2+ levels in morphine-treated SH-SY5Y cells and reversed morphine-induced growth impairment in primary cortical neurons. Salidroside significantly inhibited the acquisition of morphine-induced CPP. Furthermore, salidroside reversed chronic morphine-induced alterations in synaptic function and structural plasticity in the VTA, as evidenced by both in vitro and in vivo data. Critically, salidroside enhanced neurosynaptic plasticity of dopaminergic neurons by upregulating PI3K-AKT signalling.

CONCLUSION AND IMPLICATIONS

Our findings demonstrate that salidroside improves the synaptic structural and functional plasticity of VTA dopaminergic neurons through upregulating PI3K-AKT signalling, thereby attenuating the acquisition of morphine-induced CPP. Overall, salidroside exhibits promising preclinical potential as a therapeutic candidate for attenuating the acquisition of morphine-induced CPP.

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.

Identification of new small molecules for selective inhibition of SERCA 1 in patient-derived metastatic papillary thyroid cancer

BACKGROUND AND PURPOSE

Papillary thyroid cancer (PTC) is a general thyroid cancer subtype; however, PTC is associated with metastasis or recurrence via anti-cancer drug resistance, rendering it practically incurable. Therefore, effective and reliable clinical approaches are urgently required.

EXPERIMENTAL APPROACH

We demonstrated the coordinated up-regulation of sarco/endoplasmic reticulum (ER) calcium ATPase 1 (SERCA1) in metastatic PTC under treatment with sorafenib or lenvatinib. We screened novel drug candidates in a patient-derived lymph node metastatic PTC and compared outcomes with those in non-metastatic and main mass PTC in an in vitro and in vivo model to propose a new clinical strategy.

KEY RESULTS

In the current study using patient-derived metastatic PTC cells, SERCA1 was considerably increased under sorafenib- or lenvatinib-treated conditions. SERCA is a critical component in cytosolic free calcium regulation and is regulated by calcium/calmodulin-dependent protein kinase 2 alpha (CaMK2α) via NFκB. However, cardiac dysfunction was inevitable in vivo because of non-specific inhibition of SERCA isoforms by conventional SERCA inhibitors. This study designed a therapeutic approach with decreased cardiac dysfunction via SERCA1 isoform-specific inhibition by novel small molecules, CKP1 and CKP2, under severe ER stress conditions in patient-derived metastatic PTC. These novel SERCA1-specific inhibitors remarkably increased tumour shrinkage in the patient-derived metastatic PTC xenograft tumour model without cardiac dysfunction when used in combination with sorafenib or lenvatinib.

CONCLUSION AND IMPLICATIONS

These outcomes suggest the potential efficacy of the novel combination strategy that uses targeted therapy to treat malignant cancer cells, such as sorafenib- or lenvatinib-resistant cancer cells.

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.

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.

Antibiotic-induced decrease of bacterial load in guinea pig intestine reduces α2-adrenoceptor expression and activity in peristaltic motor inhibition

BACKGROUND AND PURPOSE

The use of analgosedatives in critically ill patients carries the risk of impairing gastrointestinal (GI) propulsion and could thereby lead to sepsis. The gut microbiota can influence GI motility, but whether GI microbial dysbiosis modifies GI peristalsis impairment by analgosedative drugs has not yet been analysed. This question was addressed in the guinea pig small intestine following a decrease of bacterial load by antibiotic pretreatment.

EXPERIMENTAL APPROACH

Guinea pigs were enorally (within the mouth) pretreated with meropenem, neomycin and vancomycin, and antibiotic-induced decrease of bacterial load was confirmed by 16S rDNA sequencing. Peristalsis in the isolated guinea pig small intestine was evaluated by determining the pressure threshold at which a peristaltic wave is triggered. The expression of factors that may be relevant to communication between GI microbiota and the motor system was examined at the mRNA (quantitative (q)PCR]) and/or protein (enzyme-linked immunosorbent assay [ELISA]) level.

KEY RESULTS

Antibiotic treatment disturbed the small intestinal microbiome as shown by decrease of bacterial load and reduced alpha diversity. Microbial dysbiosis did not affect peristalsis at baseline but blunted the ability of α2 agonists to inhibit peristalsis, while the anti-peristaltic effects of sufentanil, midazolam, neostigmine and propofol were inconsistently affected. These functional alterations were complemented by a decreased expression of α2-adrenoceptors, toll-like receptors (TRL) 3, 4 & 7, IFN-γ and iNOS.

CONCLUSION AND IMPLICATIONS

Antibiotic-induced decrease of bacterial load in the small intestine selectively blunts the ability of α2 agonists to impair peristalsis. This effect is explained by decreased α2-adrenoceptor expression, which may arise from TLR down-regulation in the dysbiotic gut.

Involvement of the somatosensory-autonomic reflex and muscarinic receptors in exacerbation of allergic pulmonary inflammation by electroacupuncture

BACKGROUND AND PURPOSE

Emerging evidence suggests that electroacupuncture (EA) could cause autonomic reflexes to modulate visceral functions. However, the efficacy and underlying mechanisms for somatic stimulation on allergic pulmonary inflammation (API) remain elusive.

EXPERIMENTAL APPROACH

Mice were administered intranasal Papain to induce API. Distinct current (0,0.1, 0.2 and 0.5 mA) of EA at the back BL13, hindlimb ST36 and forelimb LU5 acupoint were then carried out. The control group underwent the same procedure but without current stimulation. Changes in API was assessed using immunohistochemistry, flow cytometry and haematoxylin and eosin (H&E) staining. Pharmacological approaches were used to investigate the underlying mechanisms of EA effects on API.

KEY RESULTS

EA at the back region but not limb regions, in a current intensity-dependent manner, exacerbated API, primarily causing a decrease in the survival rate and intensified inflammation in the lung, including the infiltration of lung type 2 innate lymphoid cells and eosinophils, and lung pathology scores. Blocking local thoracic sensory nerves with lidocaine or lung-innervated autonomic nerves with hexamethonium eliminates the EA-produced detrimental effects. Chemical pulmonary sympathectomy with 6-OHDA further enhanced lung pathology scores, but inhibiting the activity of pulmonary muscarinic receptors was sufficient to prevent the exacerbation of API induced by EA.

CONCLUSION AND IMPLICATIONS

Our findings suggest that BL13 EA induces a somatic-autonomic reflex involving the pulmonary muscarinic receptors, thereby exacerbating API. The selective and intensity-dependency activation of body thoracic regions in driving pulmonary autonomic pathways could help optimise stimulation parameters, enhancing both efficacy and safety in modulating API.

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.

Identification of active ingredients from Lamiophlomis rotata that increase wound repair in mouse skin

BACKGROUND AND PURPOSE

We previously showed that the iridoid glycoside extract of Lamiophlomis rotata (IGLR) induces M2 macrophage polarisation to accelerate wound healing. The potentially active compounds (quality markers) in IGLR that accelerate wound healing have not been elucidated; we here identified quality markers that accelerate wound healing.

EXPERIMENTAL APPROACH

After IGLR gavage of dorsal excisional wound mice and normal mice for 7 days, the tissues were analysed using the matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry imaging (MSI) method and were further validated by liquid chromatography/mass spectrometry (LC/MS) coupled with multivariate analyses to identify quality markers.

KEY RESULTS

Using the MSI assay, Shanzhiside methyl ester (SM), 8-O-acetylshanzhiside methyl ester (ASM) and Phlorigidoside C (PhC) were identified as the quality markers in IGLR and overlapped with endogenous metabolites (lactate, citrate and itaconate) in the same class by UMAP manifold analysis. Additionally, the results were also confirmed by UPLC-Q/TOF-MS coupled with multivariate analyses of the skin tissues in normal and wound groups. MSI data from the livers and kidneys revealed that the accumulation of SM, ASM and PhC in the livers significantly increased in the model group, and the ion intensity of their glucuronide conjugates in the kidneys was decreased compared to the normal group. These results suggested that bioavailability of these compounds was improved in the wound group.

CONCLUSIONS AND IMPLICATIONS

The overall data demonstrated that SM, ASM and PhC were selectively increased in new granulation tissues, and are most likely the quality markers that accelerate wound healing.

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.

Best practices for blood collection and anaesthesia in mice: Selection, application and reporting

Blood collection in mice is a common procedure in biomedical research. The choice of blood collection method and the need for analgesia and/or anaesthesia depend on multiple factors, including the experimental setup, animal welfare considerations and the intended downstream analyses. This minireview describes key non-surgical and surgical blood collection techniques, the appropriate use of analgesia and anaesthesia, and the best practice for documentation and adherence to reporting standards in animal studies. We here provide a table summarising collection procedures; a table listing animal welfare guidelines from multiple countries; a table describing the most common analgesics and anaesthetics, with doses and route of administration; and a table outlining key points for reporting blood collection, anaesthesia and analgesia protocols. A decision chart is also included to assist in selecting the most suitable method. Ultimately, with this minireview, we aim to promote standardised practices, improve data reproducibility, and support ethical animal research.

Sculponeatin A induces mitochondrial dysfunction in non-small cell lung cancer through WWP2-mediated degradation of mitochondrial STAT3

BACKGROUND AND PURPOSE

The phosphorylation of signal transducer and activator of transcription 3 (STAT3) monomer at S727 promotes its mitochondrial localisation and regulates mitochondrial function, thus exerting a protective effect on tumour cells. However, no inhibitor drugs targeting mitochondrial STAT3 (mitoSTAT3) or S727-STAT3 phosphorylation have been identified. Here, we report a novel diterpenoid extracted from Isodon sculponeatus, sculponeatin A (sptA), induces mitochondrial dysfunction in non-small cell lung cancer (NSCLC) by targeting mitoSTAT3 degradation.

EXPERIMENTAL APPROACH

xCELLigence real-time cell analysis assay and high-content analysis were performed to measure cytotoxicity. Mitochondrial function was assessed by transmission electron microscopy, mitochondrial permeability transition pore opening and Seahorse cellular flux assays. The effects of sptA on the upstream signalling pathway of mitochondrial dysfunction were measured by Western blot, gene alterations and other approaches. Immunofluorescence and live cell imaging were performed to visualise the expression and position of mitoSTAT3. Nude mice and zebrafish were modelled with subcutaneous xenografts. Pharmacokinetics of sptA were examined in rats. Drug toxicity was evaluated in zebrafish.

KEY RESULTS

sptA inhibited mitochondrial respiration in NSCLC cells. sptA induced mitochondrial dysfunction by promoting the degradation of mitoSTAT3. sptA promoted WW domain containing E3 ubiquitin protein ligase 2 (WWP2)-mediated ubiquitination and degradation of mitoSTAT3 through direct binding. sptA inhibited tumour growth in vivo. Evaluation of drug toxicity in zebrafish showed that overdose of sptA may cause heart damage.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that pharmacological targeting the degradation of mitoSTAT3 by sptA may provide therapeutic benefits against NSCLC.

An antisense oligonucleotide targeting the heat-shock protein HSPB5 as an innovative therapeutic approach in pulmonary fibrosis

BACKGROUND AND PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by fibroblast activation and abnormal accumulation of extracellular matrix in the lungs. We previously demonstrated the importance of the heat shock protein αB-crystallin (HSPB5) in TGF-β1 profibrotic signalling, which suggests that HSPB5 could be a new therapeutic target for the treatment of IPF. The purpose of this study was thus to develop antisense oligonucleotides targeting HSPB5 and to study their effects on the development of experimental pulmonary fibrosis.

EXPERIMENTAL APPROACH

Specific antisense oligonucleotides (ASO) were designed and screened in vitro, based on their ability to inhibit human and murine HSPB5 expression. The selected ASO22 was characterized in vitro in human fibroblast CCD-19Lu cells and A549 epithelial pulmonary cells, as well as in vivo using a mouse model of bleomycin-induced pulmonary fibrosis.

KEY RESULTS

ASO22 was selected for its capacity to inhibit TGF-β1-induced expression of HSPB5 and additional key markers of fibrosis such as plasminogen activator inhibitor-1, collagen, fibronectin and α-smooth muscle actin in fibroblastic human CCD-19Lu cells as well as plasminogen activator inhibitor-1 and α-smooth muscle actin in pulmonary epithelial A549 cells. Intra-tracheal or intravenous administration of ASO22 in bleomycin-induced pulmonary fibrotic mice decreased HSPB5 expression and reduced fibrosis, as demonstrated by decreased pulmonary remodelling, collagen accumulation and Acta2 and Col1a1 expression.

CONCLUSION AND IMPLICATIONS

Our results suggest that an antisense oligonucleotide strategy targeting HSPB5 could be of interest for the treatment of IPF.

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.

Mitofusin 2 Mediates the Protective Effect of NR6A1 Silencing Against Neuronal Injury in Experimental Stroke Models

An abnormal increase in the expression of nuclear receptor subfamily 6 group A member 1 (NR6A1) in the hippocampus has been reported to result in depressive-like behavior in mice. However, the role of NR6A1 in the progression of neuronal death induced by ischemic stroke remains unknown. In this study, we observed an increase in NR6A1 in neurons in both in vivo and in vitro cerebral ischemic models. We found that knocking down NR6A1 in HT-22 neuronal cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) attenuated mitochondrial dysfunction and endoplasmic reticulum (ER) stress. Conversely, NR6A1 overexpression exacerbated neuronal damage following OGD/R. NR6A1 hindered the transcription of mitonfusin 2 (MFN2), leading to a decrease in its expression. In contrast, MFN2 conferred the protective effect of NR6A1 silencing against both mitochondrial dysfunction and ER stress. In addition, NR6A1 silencing also attenuated brain infarction, ER stress, neuronal apoptosis, and loss of MFN2 in mice subjected to middle cerebral artery occlusion/reperfusion. These findings indicate that NR6A1 is a promising target for the treatment of neuronal death following cerebral ischemia. Furthermore, these results confirm the involvement of MFN2 in the effects of NR6A1 silencing. Therefore, targeting NR6A1 has potential as a viable strategy for the treatment of ischemic stroke.

Interactions between ADGRF1 (GPR110) and extracellular matrix proteins govern its effects on tumorigenesis in HER2-positive breast cancer

BACKGROUND AND PURPOSE

We and others have previously shown that ADGRF1, an adhesion G protein-coupled receptor, is overexpressed and associated with poor survival in many cancers, including human epidermal growth factor receptor-2 (HER2) breast cancer (BC). Also, we have reported the tumour-promoting function of ADGRF1 using preclinical models of HER2+ BC. In this study, we investigated the effect of ADGRF1 overexpression in an orthotopic in vivo model as well as downstream signalling of ADGRF1 in HER2+ BC.

EXPERIMENTAL APPROACH

We utilized a doxycycline (Dox)-induced ADGRF1 overexpression system in HER2+ BC cell lines and performed various in vitro and in vivo studies. Following ADGRF1 overexpression in the presence/absence of Matrigel, laminin-111 or collagen-IV, we performed the mammosphere assay to assess the tumorigenicity of breast epithelial cells, as well as cAMP/IP1 assays and RNA-sequencing, to understand the receptor function and pharmacology. We conducted cross-linking-aided immunoprecipitation and mass spectrometry to confirm the physical interaction between ADGRF1 and the extracellular matrix proteins present in Matrigel.

KEY RESULTS

We found that ADGRF1 switched from a tumour-promoting to tumour-suppressive function upon interaction with laminin-111. Interaction of ADGRF1 with laminin-111 resulted in inhibition of Gαs coupling and STAT3 phosphorylation, induction of senescence, increase in HER2 expression, and improvement of sensitivity to anti-HER2 drugs in HER2+ BC.

CONCLUSIONS

ADGRF1 switches from a tumour-promoting to tumour-suppressive function upon interaction with laminin-111, leading to improvements in sensitivity to anti-HER2 drugs. Leveraging ADGRF1 interactions with laminin-111 may allow the design of novel therapies against ADGRF1 in HER2+ BC.

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.

Sex differences in the effects of maternal voluntary oral Cannabis consumption on the metabolic outcomes of high-fat diet in adult offspring

BACKGROUND AND PURPOSE

Given the recent rise in Cannabis legalisation, accessibility to Cannabis and consumption have increased during pregnancy. Therefore, there could be unintended developmental consequences. The endocannabinoid system plays a key role in fetal development and later-life energy homeostasis. We explored the long-term effects of maternal voluntary Cannabis consumption on the metabolic outcomes of a high-fat diet (HFD) in adult offspring.

EXPERIMENTAL APPROACH

Pregnant mice voluntarily consumed Cannabis extract equivalent to 5 mg kg-1 day-1 Δ9-tetrahydrocannabinol (THC) from gestational day 1.5 until postnatal day (PD) 10. Pregnancy and pup outcomes and active maternal behaviour were recorded. Male and female offspring (PD49) were placed on a 12-week HFD or control diet; their weight gain, adiposity, glucose tolerance, insulin sensitivity, circulating hormones and pancreatic structure were measured.

KEY RESULTS

Perinatal Cannabis exposure (PCE) pup weight was initially reduced but restored by PD16. PCE did not influence weight gain or metabolic characteristics of male mice on a HFD. PCE female but not male offspring on a HFD had reduced accumulation of adipose tissue and lower insulin, leptin and resistin independent of body weight. PCE females on control diet also showed altered basal insulin sensitivity likely because of increased glucagon levels in parallel with reduced islets of Langerhans size and enhanced gene expression of cannabinoid 2 receptors in white adipose tissue.

CONCLUSION AND IMPLICATIONS

PCE adversely affected glycaemic control in female offspring on control diet while it mitigated HFD-induced metabolic dysfunction. This raises concerns about the long-term effects of PCE on the metabolic health of offspring.

Oral hyoscine butylbromide exerts spasmolytic effects in both gastrointestinal and urogenital tissues in rats

BACKGROUND AND PURPOSE

Hyoscine butylbromide (HBB) has a low oral (PO) bioavailability. Further, limited data on its activity on non-gastrointestinal (GI) smooth muscle spasms after oral dosing are available, causing its effects beyond the GI tract to be questioned. This pharmacokinetic/pharmacodynamic (PK/PD) study, conducted using female rats, aimed to cover this gap.

EXPERIMENTAL APPROACH

PK study: HBB and atropine (as a comparator agent) were administered PO and IV to rats, and concentrations in plasma and tissues (colon, uterus and urinary bladder; CUB) were measured. PD study 1: concentration-response curves of HBB and atropine (10-9-10-4 M) were obtained for carbachol-induced (10-5 M) pre-contracted tissues; PD study 2: CUB were pre-incubated with HBB and atropine at maximum concentrations (Cmax) from PK studies and carbachol concentration-response curves (10-9-10-4 M) were obtained; PD study 3: HBB and atropine were administered PO and IV to rats as for PK study, CUB tissues were collected at 0.5 h (IV) and 4 h (PO), and carbachol concentration-response curves (10-9-10-4 M) obtained.

KEY RESULTS

PO HBB showed higher Cmax in CUB tissues than in plasma. HBB and atropine reduced, concentration-dependently, carbachol-induced contractions in CUB tissues. PO HBB showed highest spasmolytic activity in colon (40%), followed by uterus (30%) and urinary bladder (10%).

CONCLUSION AND IMPLICATIONS

This is the first comparison of PO and IV HBB and atropine in GI and non-GI tissues. Despite low bioavailability, PO HBB accumulated and exerted spasmolytic effects in tissues beyond the GI tract.

Cannabidiol dose dependently reduces alcohol intake in mice via a non-5-HT1A receptor mechanism: Exploration of other potential receptor targets

BACKGROUND AND PURPOSE

Binge drinking is a risky pattern of alcohol intake and a major predictor of alcohol use disorder (AUD). Current AUD medications have limited efficacy and poor patient compliance, calling for more effective therapeutics. Cannabidiol (CBD), a non-intoxicating component of cannabis, has emerged as a potential novel therapeutic. However, receptor mechanisms in CBD's alcohol-related effects have not been investigated comprehensively.

EXPERIMENTAL APPROACH

Using the murine drinking-in-the-dark model of binge drinking, our research aimed to confirm a reduction of alcohol consumption with CBD (7.5, 15, 30, 60, 120 mg kg-1) in male and female mice. Behavioural pharmacological approaches were used to explore CBD interactions with identified target mechanisms: serotonin-1A receptor (5-HT1AR) and peroxisome proliferator-activated receptor-gamma (PPARɣ), and the novel targets, chemokine receptor type-4 (CXCR4) and neuropeptide S receptor (NPSR).

KEY RESULTS

Acute CBD dose dependently suppressed binge-like drinking and blood ethanol concentration. The effect was not driven by locomotor impairments and was maintained across sub-chronic treatment. Blockade of 5-HT1AR and PPARɣ had no impact on CBD's reduction of alcohol consumption. Co-administration of subthreshold CBD doses and a NPSR antagonist implicated NPSR blockade as a potential mechanism contributing to CBD's effect, whereas co-administration of CBD and a CXCR4 antagonist suggested CXCR4 was not involved. However, the potent and selective CXCR4 antagonist AMD3100 reduced ethanol consumption.

CONCLUSIONS AND IMPLICATIONS

CBD represents a promising candidate to reduce voluntary alcohol consumption. Mechanisms driving CBD's alcohol-related effects remain unclear and may involve polypharmacology, including actions at the NPSR identified in the present study.

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.

Pharmacological characterisation of JNJ-78911118, a novel, centrally-penetrant, selective GluN2A antagonist

BACKGROUND AND PURPOSE

Non-selective NMDA receptor antagonism produces rapid symptom improvement in treatment-resistant depression; however, associated side effects necessitate medical oversight during administration. We hypothesised that selective GluN2A antagonism could provide similar efficacy with an improved side effect profile. Here, we report the pharmacology of JNJ-78911118, a brain-penetrant, GluN2A selective antagonist.

EXPERIMENTAL APPROACH

JNJ-78911118 pharmacology and mechanism of action was characterised in vitro using fluorescence, voltage clamp and radioligand binding assays. Target engagement was measured using ex vivo receptor autoradiography, and effects on rat prefrontal cortex monoamine levels were measured using microdialysis. Synaptogenesis assays and patch clamp studies were used to demonstrate effects on synaptic plasticity. Cardiovascular safety and neurotoxicity were assessed in rats.

KEY RESULTS

JNJ-78911118 blocked GluN1/2A receptors with an IC50 of 44 nM and showed selectivity against GluN1/2B, 2C and 2D receptors. Systemic administration produced concentration-dependent receptor occupancy, increased prefrontal cortex monoamine levels in wild type, but not in GluN2A knockout mice, and blocked theta burst induced LTP in the hippocampus. In addition, it produced increases in dendritic complexity and synapse number in vitro, and increased mEPSC frequency in rat cortical neurons in vivo. In rat toxicological studies, no Olney's lesions were observed, but acute increases in heart rate and blood pressure were detected.

CONCLUSIONS AND IMPLICATIONS

JNJ-78911118 is a potent and selective GluN2A antagonist that reproduces the effect of known rapidly acting antidepressants (RAADs) on neurotransmitter levels and synaptic plasticity. This molecule is a powerful in vivo tool that will enhance understanding of GluN2A biology.

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.

PPARγ is a potential therapeutic target for radiation enteritis via suppressing ferroptosis, mediated by the GAPDH/glycosylation axis

BACKGROUND AND PURPOSE

Radiation enteritis (RE) is a severe complication after radiotherapy with no specific therapeutic agents. Here, we have attempted to identify the key therapeutic targets for RE, to advance drug development.

EXPERIMENTAL APPROACH

Therapeutic targets were screened and identified using RE patients' intestinal samples, bioinformatics, and mouse models. RNA sequencing, electron microscopy, metabolomics, glycolytic flux, co-immunoprecipitation, molecular docking, point mutation were used to identify mechanisms.

KEY RESULTS

Analysis of gene changes in response to ionising radiation showed extensive regulation of several differentially expressed genes by PPARγ, as well as its deficiency in activation and expression in RE. Both activation and overexpression of PPARγ significantly antagonised RE in vivo. Mechanistically, PPARγ specifically limited ferroptosis in intestinal epithelial cells exposed to ionising radiation, and its selective activation was more effective than full activation because of the reduced effect on the ferroptosis-driving genes PTEN and SAT1. Furthermore, ionising radiation caused the greatest changes in glucose metabolism. PPARγ targeted GAPDH at Lys107 to shift glycolysis to the hexosamine biosynthesis pathway, thereby enhancing glycosylation. In ionising radiation-induced ferroptosis, O/N-GlcNAcylation initially played antagonistic roles and later mediated the process, and they assisted PPARγ in restraining lysosomal degradation of heavy-chain ferritin (FTH1) and the transferrin receptor TFRC, thus controlling storage and transport of iron, and consequently alleviated ferroptosis.

CONCLUSION AND IMPLICATIONS

PPARγ is a potential therapeutic target for RE, as it elicits GAPDH-mediated glucose metabolic reprogramming and alleviates ionising radiation-induced ferroptosis, in a glycosylation-dependent manner.

Computational modelling for improved translation of cardiac inotropic and lusitropic drug effects from rats to humans

Telemetered rats are widely used for early drug screenings but pronounced physiological differences between rat and human hearts limit translational relevance. To address this, the study investigates the potential of computer modelling to improve the translation of inotropic and lusitropic drug effects from rats to humans, beginning at the cellular scale. To this end, computer models of rat and human left ventricular cardiomyocytes were constructed to reproduce experimental data. First, global sensitivity analyses identified distinctive differences in inotropic and lusitropic responses to the inhibition of ion channels and transporters in rats and humans. Then, the computer models were used to address the translation challenge by predicting human responses based on sarcomere length and intracellular [Ca2+] data obtained from rats. This process, referred to as computational drug effect translation, involved identifying the drug's blocking potencies on potential targets. Focussing on the identifiable targets RyR2, SERCA2, and NCX1, evaluations on synthetic data showed high translation accuracy across all biomarkers and drug concentrations. For example, coefficients of determination were ≥ 0.997 for predicted human effects compared to ≤0.771 for rat effects for percentage sarcomere shortening, and ≥ 0.905 compared to ≤0.418 for the time from peak to 90 % relaxation. Evaluations on experimental data collected for thapsigargin largely corroborated these findings. The results demonstrate that computer modelling can improve the translation of inotropic and lusitropic drug effects from rats to humans, offering potential benefits for augmenting the current drug development pipeline.

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.

A mitochondria-targeting and G-quadruplex structure-binding ligand inducing calcium overload and ferroptosis in human cancer cells

BACKGROUND AND PURPOSE

Regulation of mitochondrial calcium overload and ferroptosis with mitochondria-targeting ligands is an attractive anticancer strategy but it remains a challenge. The aim of the present study was to demonstrate that a mitochondria-targeting and mtDNA G-quadruplex-binding ligand, BYB, induced mitochondrial calcium overload and ferroptosis in HeLa cells and showed potent in vitro and in vivo anticancer activity.

EXPERIMENTAL APPROACH

Cellular functions and molecular mechanism were studied using cell viability assay, live-cell imaging, western blotting, immunofluorescence, cell uptake, cell cycle arrest and apoptosis analysis, mitochondrial metabolism analysis, Comet assay, and wound-healing analysis. Pharmacokinetic studies were conducted in rat. In vivo antitumor activity was studied in a cervical cancer HeLa cell xenograft mouse model.

KEY RESULTS

Cellular results showed that BYB induced mitochondrial calcium overload, attributed to ligand-induced mitochondrial dysfunction via the mechanism of inhibiting mitochondrial DNA replication and transcription. The expression of respiratory chain complexes was markedly downregulated in BYB-treated HeLa cells. The respiratory chain function was also dysregulated. Mitophagy and mitochondrial calcium overload were induced in BYB-treated HeLa cells. Mitochondrial calcium overload markedly induced mtROS production. The induced mtDNA stress activated cGAS-STING pathway, leading to autophagy-dependent ferroptosis. The antitumour efficacy of BYB, evaluated in a HeLa tumour xenograft mouse model, achieved over 60% tumour weight reduction.

CONCLUSION AND IMPLICATIONS

BYB, via targeting mitochondria and mtDNA G-quadruplexes, induced mitochondrial calcium overload and ferroptosis, exhibited high in vivo antitumour efficacy and low toxicity. It shows high potential to be a mitochondria-targeting lead compound for chemical biology and drug discovery.

JAK-STAT inhibitory effect of IN-115314, a novel small molecule inhibitor, and pharmacokinetic/pharmacodynamic study in canine

BACKGROUND AND PURPOSE

The JAK-STAT signalling pathway has been extensively spotlighted as a therapeutic target for various diseases. This study assessed the inhibitory effects of a novel small molecule, IN-115314, on JAK-STAT pathway.

EXPERIMENTAL APPROACH

The IC50 values of IN-115314 for JAK1-pSTAT3 and JAK2-pSTAT5 were determined in canine whole blood cells and TF-1 cells. IN-115314 administered intragastrically (0.2 to 0.9 mg·kg-1), while oclacitinib was given orally as a positive control. Both drugs were administered twice daily for 7 days. Pharmacokinetics and pharmacodynamics were analysed on Days 1 and 7, respectively.

KEY RESULTS

IC50 values for IN-115314 and oclacitinib against JAK1-pSTAT3 were 9.4 and 61.3 nM, while IC50 values against JAK2-pSTAT5 were 749 and 1214 nM, respectively. Plasma concentrations of IN-115314 increased in a dose-dependent manner without accumulation, whereas oclacitinib displayed a 1.65-fold increase in exposure (AUC relative to Day 1) across 7 days of repeated dosing. The ex vivo IL-6-induced pSTAT3 activation in circulating CD4+ T lymphocytes was maximally suppressed between 1 and 3 h after administration of IN-115314, and the inhibitory efficacy of IN-115314 at a dose of 0.45 mg·kg-1 was -31.2% ± 30.7%, comparable with that of oclacitinib at doses of 0.4-0.6 mg·kg-1 (-31.4% ± 15.8%).

CONCLUSION AND IMPLICATIONS

In summary, this study confirmed IN-115314 JAK-STAT inhibitory effect, along with data on its pharmacokinetics, pharmacodynamics, safety, efficacy and optimal dosage. We anticipate that IN-115314 will be developed as a new therapeutic agent for various diseases involving the JAK-STAT pathway.

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.

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.

Characterisation of neurogenic lipolytic responses in white adipose tissue ex vivo

BACKGROUND AND PURPOSE

Dysfunction of the autonomic nervous system is associated with cardiovascular dysfunction, including metabolic syndrome and obesity. Understanding mechanisms of neurogenic control of white adipose tissue is key to understanding adipose physiology and pathophysiology, though there is limited research exploring this in adipose tissue using pharmacological tools, as opposed to genetic knockout models.

EXPERIMENTAL APPROACH

Inguinal white adipose tissue from C57BL/6J mice was used in this study. We used immunocytochemistry to determine tissue innervation and glycerol release assays to quantify lipolysis in adipose tissue and isolated adipocytes. The voltage-gated Na+ channel opener veratridine was used to stimulate nervous activity in tissue ex vivo. The role of neurotransmitters and receptors mediating veratridine-evoked lipolysis in adipose tissue was pharmacologically characterised.

KEY RESULTS

Veratridine evoked glycerol release in white adipose tissue but not from isolated adipocytes. This release was abolished by tetrodotoxin and propranolol. Veratridine also induced noradrenaline release from white adipose tissue. Veratridine- and noradrenaline-evoked glycerol release was blocked by the β2-adrenoceptor antagonist ICI-118551 but not by the β1-adrenoceptor antagonist CGP 20712A. Purported β3-adrenoceptor antagonists L-748337 and SR59230A stimulated glycerol release from tissue and from isolated adipocytes. Neither L-748337 or SR59230A antagonised veratridine-evoked glycerol release but SR59230A antagonised noradrenaline-evoked glycerol release. We exclude contributions of sensory neuropeptides and the autonomic neurotransmitters neuropeptide Y and ATP.

CONCLUSION AND IMPLICATIONS

Neurogenic lipolytic responses can be measured in white adipose tissue ex vivo using veratridine to stimulate nerve activity. The lipolytic responses are mediated by β2-adrenoceptor activation. This study provides the first evidence of neurogenic lipolysis in tissue ex vivo.

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.

Thiamine deficiency aggravates experimental colitis in mice by promoting glycolytic reprogramming in macrophages

BACKGROUND AND PURPOSE

Inflammatory bowel disease (IBD) is closely associated with immune dysfunction, where nutrient-mediated metabolic flux dictates immune cell fate and function. Thiamine is a central water-soluble vitamin involved in cellular energy metabolism, and its deficiency has been reported in IBD patients. However, whether thiamine deficiency is a cause or consequence of IBD pathogenesis remains unclear. The current study aimed to reveal the immunometabolic regulation of macrophages and underlying mechanism of thiamine deficiency in colitis development.

EXPERIMENTAL APPROACH

Thiamine deficiency was induced in C57BL/6 mice and bone marrow-derived macrophages (BMDMs), by administering a thiamine-deficient diet/medium together with pyrithiamine hydrobromide. The frequency of macrophage phenotypes and their intracellular metabolism were detected using flow cytometry and non-targeted metabolomics, respectively.

KEY RESULTS

Thiamine deficiency aggravated ulcerative colitis in mice and promoted the infiltration of proinflammatory M1 macrophages in colonic lamina propria. Our mechanistic study revealed that thiamine deficiency impaired pyruvate dehydrogenase (PDH) activity, thereby reprogramming cellular glucose metabolism to enhance glycolysis and lactic acid accumulation in M1 macrophages. Using a well-established PDH inhibitor (CPI-613) and lactic acid dehydrogenase inhibitor (galloflavin), we further demonstrated that PDH inhibition mimics, while lactate dehydrogenase inhibition partially rescues, thiamine deficiency-induced proinflammatory macrophage infiltration and experimental colitis in mice.

CONCLUSION AND IMPLICATIONS

Our study provides evidence linking thiamine deficiency with proinflammatory macrophage activation and colitis aggravation, suggesting that monitoring thiamine status and adjusting thiamine intake is necessary to protect against colitis.

Assessment of Spinster homologue 2 (Spns2)-dependent transport of sphingosine-1-phosphate as a therapeutic target

BACKGROUND AND PURPOSE

Sphingosine-1-phosphate (S1P) receptor modulator (SRM) drugs suppress immune system function by disrupting lymphocyte trafficking, but SRMs are broadly immunosuppressive with on-target liabilities. Another strategy to modulate the immune system is to block S1P transport. This study tests the hypothesis that blockers of S1P transport (STBs) mediated by Spinster homologue 2 (Spns2) approximate the efficacy of SRMs without their adverse events.

EXPERIMENTAL APPROACH

We have discovered and optimized STBs to enable investigations of S1P biology and to determine whether S1P transport is a valid drug target. The STB SLF80821178 was administered to rodents to assess its efficacy in a multiple sclerosis model and to test for toxicities associated with SRMs or Spns2-deficient mice. Further, potential biomarkers of STBs, absolute lymphocyte counts (ALCs) in blood and S1P concentrations in plasma and lymph, were measured.

KEY RESULTS

SLF80821178 resembles SRMs in that it is efficacious in a standard multiple sclerosis model but does not evoke bradycardia or lung leakage, common to the SRM drug class. Also, chronic SLF80821178 administration does not affect auditory responses in adult mice despite the neurosensorial hearing defect observed in Spns2-null mice. While both SRM and STB administration decrease ALCs, the maximal effect is less with an STB (45% vs. 90%). STBs have minimal effects on S1P concentration in plasma or thoracic duct lymph.

CONCLUSION AND IMPLICATIONS

We found nothing to invalidate Spns2-dependent S1P transport as a drug target. Indeed, STBs could be superior to SRMs as a therapy to modulate immune system function.

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.

A subtype-selective photoswitchable agonist for precise manipulation of GABAA receptors

BACKGROUND AND PURPOSE

Neuronal inhibition is largely mediated by type-A GABA receptors (GABAARs), a family of ligand-gated chloride-permeable channels, which can be sub-classified by their subunit composition. Unravelling the function and distribution of each GABAAR subtype is essential for a holistic understanding of GABAergic inhibition in health and diseases. Photopharmacology, a technique that utilises light-sensitive compounds to precisely manipulate endogenous proteins, is powerful for this purpose. To resolve the molecular complexity of neuronal inhibition, we aimed to develop subtype-selective photoswitchable agonists for GABAARs.

EXPERIMENTAL APPROACH

Inspired by THIP (gaboxadol), an agonist selective for δ subunit-containing GABAARs (δ-GABAARs), we merged a photoswitch moiety (azobenzene) with an analogue of THIP (isoguvacine) to construct Az-IGU. Using whole-cell voltage-clamp recording, Az-IGU was tested on 13 GABAAR subtypes expressed in human embryonic kidney (HEK) cells. Optical activation of endogenous GABAARs was examined via electrophysiology in cultured cortical neurons.

KEY RESULTS

In HEK cells, Az-IGU exerted reversible photo-agonism selectively for α4β3δ and α6β3δ GABAARs, two major mediators of tonic inhibition. Pharmacological and mutagenesis studies suggested that activation of the α4β3δ GABAAR involves interaction between Az-IGU and the GABA-binding pocket and is strongly correlated with the spontaneous activity of the receptor. In cultured cortical neurons, photoisomerisation of Az-IGU triggered responses that enabled reversible control of action potential firing.

CONCLUSIONS AND IMPLICATIONS

GABAARs are potential therapeutic targets for many disorders. However, their physiological and pathophysiological roles remain largely unexplored. Az-IGU may enable photopharmacological studies of α4/6β3δ GABAARs, providing new opportunities for biomedical and neurobiological applications.

Dehydroabietic acid protects against cerebral ischaemia-reperfusion injury by modulating microglia-mediated neuroinflammation via targeting PKCδ

BACKGROUND AND PURPOSE

Cerebral ischaemia-reperfusion injury (CIRI) is a major contributor to global morbidity and mortality, although its underlying mechanisms remain only partly understood. Emerging evidence indicates that inhibiting microglia-mediated neuroinflammation would be an effective therapeutic approach for CIRI, and pharmacological interventions targeting this pathway hold significant therapeutic promise. This study aimed to identify a potent anti-inflammatory drug from a natural compound library as a potential treatment for CIRI.

EXPERIMENTAL APPROACH

We used oxygen-glucose deprivation/reperfusion (OGD/R) and middle cerebral artery occlusion in male C57BL/6 mice to evaluate the efficacy of DHA in neurological deficits and the anti-inflammatory effects. Using BV2 cells and murine brain tissue, liquid chromatography-tandem mass spectrometry was used to identify potential molecular targets of DHA, followed by bio-layer interferometry, molecular docking, molecular dynamics simulations and cellular thermal shift assays to validate DHA's binding interactions with protein kinase C delta (PKCδ).

KEY RESULTS

DHA decreased production of pro-inflammatory cytokines following OGD/R, thereby inhibiting microglia-mediated neuroinflammation to protect neurons and reducing brain infarct size and improving neurological outcomes. Mechanistically, DHA directly bound to PKCδ, inhibiting its phosphorylation and downstream NF-κB signalling. This binding interaction involved TRP55 and LEU106 on PKCδ, as confirmed by molecular docking and other biophysical techniques.

CONCLUSION AND IMPLICATIONS

DHA specifically interacts with PKCδ, preventing its phosphorylation induced by ischaemia-reperfusion injury. These results suggest that DHA is a novel inhibitor of PKCδ and provide solid experimental foundations for using DHA in treating neuroinflammation-related conditions, such as CIRI.

GNS561 (ezurpimtrostat), a small basic lipophilic molecule, prevents lupus phenotype in a pristane-induced lupus mouse model

BACKGROUND AND PURPOSE

Systemic lupus erythematosus is an autoimmune, multisystemic disease affecting all organs in the body. Accrued evidence has elucidated a role for autophagy in the onset and severity of systemic lupus erythematosus. The antimalarial drug hydroxychloroquine constitutes the cornerstone of standard of care for systemic lupus erythematosus, together with glucocorticoids and immunosuppressants or biologics, and all accompanied by various side effects.

EXPERIMENTAL APPROACH AND OBJECTIVE

Our study aimed to investigate the potential of GNS561 (ezurpimtrostat) treatment, a small basic lipophilic molecule that induces lysosomal dysregulation, using the pristane-induced lupus mouse model.

KEY RESULTS

Compared with hydroxychloroquine, GNS561 treatment presents a more pronounced impact on the development of pathogenic anti-antibodies in pristane-induced lupus mice. Next, focussing on clinical impact, we showed that GNS561 significantly reduced clinical signs of lupus in pristane-induced lupus by preventing the incidence and severity of arthritis, occurrence of nephritis and lung damage. Finally, GNS561 modulated the inflammatory profile in pristane-induced lupus mice through a reduction of the lipogranuloma score. Interestingly, focussing on interferon-α, only pristane-induced lupus mice treated by GNS561 presented a significant decrease of the cytokine, suggesting a higher efficacy for GNS561 in the modulation of lupus-induced inflammation compared with hydroxychloroquine.

CONCLUSION

All results show that GNS561, but not hydroxychloroquine, represents as an effective treatment to prevent clinical and inflammatory signs of lupus in this mouse model.

IMPLICATIONS

Altogether, this study highlights GNS561 as a promising investigational drug for systemic lupus erythematosus.

Nimodipine reduces microglial activation in vitro as evidenced by morphological phenotype, phagocytic activity and high-throughput RNA sequencing

BACKGROUND AND PURPOSE

Nimodipine, an L-type voltage-gated calcium channel blocker, is an approved cerebral vasorelaxant. We hypothesized that nimodipine attenuates the pro-inflammatory shift in microglial phenotypes. Here, we analysed the effects of nimodipine on morphological and functional microglial phenotypes as well as their transcriptomic profile.

EXPERIMENTAL APPROACH

Live brain slice preparations from C57BL/6 mice and primary microglia cultures from neonatal Sprague Dawley rats were used. Microglia were activated either by ischemia or lipopolysaccharide (LPS), and preparations were treated with nimodipine (5-10-20 μM). Microglial morphological phenotypes, phagocytic activity, Iba1 expression and TNF-α levels were evaluated. Total RNA was isolated from monocultures and processed for next generation RNA sequencing.

KEY RESULTS

LPS resulted in a pro-inflammatory microglial phenotype, affecting the expression of cytokines, the complement system and phagocytosis-related genes. LPS increased the transcription of ionotropic purinergic and TRP channels but decreased the expression of voltage- and ligand-gated calcium channels, down-regulated the expression of Ryr and IP3 receptors and increased transcription of the SERCA calcium pump. Nimodipine suppressed the amoeboid morphological transformation and phagocytosis and altered the expression of 110 genes in the opposite direction to LPS activation, of which at least 20 were associated with the microglial immune response, seven with cell adhesion and two with autophagy regulation.

CONCLUSION AND IMPLICATIONS

The effect of nimodipine goes beyond cerebral vasorelaxation. Nimodipine attenuates microglial activation by modulating Ca2+-dependent gene expression involved in intracellular signalling cascades to drive microglial immune responses. Consideration should be given to expanding the use of nimodipine beyond vasorelaxation.

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.