Effects Of Inhibitors Research Articles

The effect of CD38 inhibition in age-associated vascular dysfunction

Abstract Introduction Aging is characterized by age-related vascular dysfunction, mainly caused by endothelial dysfunction and arterial stiffness. Levels of nicotinamide adenine dinucleotide (NAD) decrease with aging and accordingly, NAD is thought to be involved in the progression of age-related vascular dysfunction. Recent studies reported the involvement of CD38 in NAD regulation; indeed, its inhibition significantly prolongs the lifespan of progeroid and aged mice. However, whether CD38 is involved in the progression of age-related vascular dysfunction remains to be investigated. Methods CD38 expression was investigated in aortic homogenates of young (12-16 weeks) and aged (18-24 months) C57BL/6 wild-type mice, as well as in vitro in young (passage 5-7) and senescent (passage 14-15) primary human aortic endothelial cells (HAECs). Ex vivo tension myograph experiments were performed on thoracic aortas isolated from aged C57BL/6 mice (22-24 months old) pre-incubated for 1 hour with CD38-specific inhibitor, 78c, or DMSO as control. The effect of CD38 inhibition was also observed in vitro in senescent HAECs. Results A significant upregulation of CD38 expression was detected in the aortas of aged mice compared to the young ones as well as in senescent HAECs compared to young cells. Ex vivo tension myograph experiments showed a significant increase in endothelium-dependent relaxation responses to acetylcholine upon CD38 inhibition. The improvement of endothelial function was prevented by the addition of endothelial nitric oxide synthase (eNOS) inhibitor (L-NAME), but not by the COXs inhibitor, indomethacin, indicating that the observed effect achieved by CD38 inhibition is eNOS dependent. The involvement of the eNOS pathway was further supported by the in vitro finding in HAECs of increased eNOS activation upon CD38 inhibition. Conclusion The herein-reported data suggests an involvement of CD38 in the development of age-related endothelial dysfunction. Further studies are ongoing to investigate the underlying molecular mechanisms as well as the effect of long-term CD38 inhibitor supplementation on the progression of age-related vascular dysfunction.

Interleukin-6 signalling, lipoprotein (a) lowering and cardiovascular disease: a mendelian randomisation study

Abstract Background Elevated lipoprotein(a) (Lp[a]) levels and chronic low-grade inflammation play causal roles in cardiovascular disease (CVD) development, representing promising targets for managing residual risk. CVD prevention trials are currently assessing the efficacy of IL-6 pathway inhibition in ameliorating chronic pro-atherogenic inflammation. Lp(a) increases in response to interleukin 6 (IL-6) and acute inflammatory states, and Lp(a) itself induces an inflammatory response that accelerates atherosclerosis. Recent studies indicate that IL-6-receptor inhibitors may lower Lp(a) levels and reduce inflammation, potentially decreasing CVD risk in an additive manner. Purpose This drug-target Mendelian Randomisation (MR) study aims to elucidate the on-target effects of pharmacological IL-6R and LPA inhibition on CVD and explore the relationship between downregulated IL6R signalling and Lp(a) levels. Methods Independent genetic variants associated with C-reactive protein levels from around the IL6R gene locus, and Lp(a) lowering variants from around the LPA gene locus were utilised to assess the effect of genetically proxied IL6R and LPA inhibition on CVD risk in large genomic consortia. Two-step cis-MR was then employed to estimate the effect of lower genetically predicted IL6R signalling on CVD, after adjusting for its influence on Lp(a) levels. Results Genetically proxied LPA inhibition was associated with reduced odds of coronary artery disease (CAD) (OR 0.88, 95% CI 0.86-0.89), ischaemic stroke (IS) (OR 0.98, 95% CI 0.96-1.00), cardioembolic stroke (OR 0.95, 95% CI 0.92-0.97), heart failure (HF) (OR 0.96, 95% CI 0.92-1.00), and aortic stenosis (OR 0.88, 95% CI 0.85-0.91). IL6R inhibition was associated with reduced odds of CAD (OR 0.76, 95% CI 0.68-0.86), IS (OR 0.89, 95% CI 0.80-0.98), small vessel stroke (SVS) (OR 0.72, 95% CI 0.59-0.89), large artery stroke (LAS) (0.61, 95% CI 0.48-0.78) and atrial fibrillation (OR 0.73, 95% CI 0.65-0.83). Furthermore, downregulated IL6R signalling was associated with lower Lp(a) levels (SD change -0.04, 95% CI -0.08,-0.01). In two-step cis-MR, Lp(a) levels partially mediated the total effect of IL6R inhibition on CAD (proportion-mediated = -11.33%, 95% CI -11.35, -11.31%) and LAS (proportion mediated = -4.19%, 95% CI -4.21, -4.17%), but had little effect on IS (proportion-mediated = -1.78%, 95% CI -1.80, -1.76%), SVS (proportion-mediated = -2.50%, 95% CI -2.52, -2.48%), or atrial fibrillation (proportion-mediated = -0.20%, 95% CI -0.22, -0.18%). Conclusion IL6R and Lp(a) inhibition are independently associated with reduced risk of CVD. Furthermore, IL6R inhibition is associated with lower Lp(a) and its effect on CVD is independent of its Lp(a)-lowering effects. Targeting the IL6 signalling pathway offers a promising approach to mitigate residual CVD risk in individuals with elevated Lp(a) levels. Future trials should investigate the additive effects of combined IL-6 inhibition and Lp(a) lowering therapies.

Effect of interleukin 1b inhibition with canakinumab on inflammation and viral persistence in people with human immunodeficiency virus

Abstract Introduction Effectively treated people with HIV (PWH) have elevated risk of cardiovascular disease (CVD). Inflammatory markers are predictive of CVD and mortality among PWH. The role of the myeloid system in driving inflammation and atherosclerosis has been recently recognized. Canakinumab (a monoclonal antibody to IL-1β) reduces inflammation and CVD events among people with elevated hsCRP after myocardial infarction without HIV. We evaluated the impact of IL-1β inhibition using canakinumab on HIV parameters, inflammation, HIV persistence markers, arterial inflammation, and hematopoietic activity in PWH. Methods PWH on effective ART who had CVD or were at risk for CVD were randomized 2:1 to receive 150 mg of canakinumab subcutaneously or matched placebo at weeks 0 and 12. Arterial inflammation and bone marrow metabolic activity were assessed using F18 FDG PET/CT at baseline and week 18. T cell and monocyte activation were evaluated using multiparameter spectral cytometry. The viral reservoir was quantified using Tat/rev Induced Limiting Dilution Assay (TILDA), HIV DNA and cell-associated RNA. The primary endpoints were change in CD4 and CD8 count. We assessed group effects over time using linear mixed effects models. Results 33 individuals were randomized (median age of 60 years old (IQR 57.5, 64.5) and 94% male); 25 received canakinumab and 8 received placebo. There were no significant differences at baseline. As expected, IL-1β increased among those treated with canakinumab at weeks 4- 24 (p<0.01 for each) and returned to baseline at week 36. There was one death from sepsis in an individual aged 84 with CVD and poorly controlled diabetes who received canakinumab. There were no significant changes in CD4 count, CD8 count, platelet count, creatinine, AST, or ALT by group. Treatment was not associated with a greater reduction in arterial inflammation in the most diseased segment compared to placebo (-6.9%; 95% CI -30.4 to 24.5%; p=0.62). However, bone marrow metabolic activity decreased in the canakinumab group versus placebo (-14.4%, 95% CI -26.5% to -0.2%; p=0.047). Treatment was associated with increased CD163 expression on monocytes at weeks 24 (p=0.03) and 36 (p<0.001), and lower caspase activity at week 36 (p=0.02). There was expansion of anti-inflammatory CD16+ patrolling monocytes that co-express CD163+CX3CR1+ and a decrease in pro-inflammatory CD16+ patrolling monocytes that are Caspase1+CCR2+. Treatment was not associated with differences in hsCRP, IL-6, IL-16, IL-18, MCP-1, sCD14, sCD163, T cell subsets, NK cell subsets, or viral persistence markers. Conclusion Among treated PWH, targeted inhibition of IL-1β using canakinumab results in decreased bone marrow metabolic activity and a shift toward anti-inflammatory monocyte populations. These findings shed light on mechanisms underlying how targeted IL-1β inhibition using canakinumab prevents CVD events by altering monocyte populations and reducing systemic inflammation.

Treatment of Post-COVID-19 POTS by inhibiting FcRn: a phase 2 randomized, placebo controlled, double-blind, proof of concept study with efgartigimod

Abstract Background While the underlying pathophysiology is unknown, post–COVID-19 postural orthostatic tachycardia syndrome (POTS) may be related to immune dysfunction and autoimmunity precipitated by SARS-CoV-2 infection. Various autoantibodies, including those targeting G-protein coupled receptors (GPCRs), have been observed in patients with POTS. Binding of these autoantibodies to adrenergic receptors, which are prototypical GPCRs, has been hypothesized to modulate receptor activity, increase sympathetic tone, and cause tachycardia. Moreover, IgG anti-GPCR autoantibodies, acting as partial agonists, are thought to decrease the effect of peripheral vasomotor control, leading to an increased sympathetic response to upright posture that can result in postural tachycardia in the absence of hypotension. Purpose We hypothesize that a reduction in autoantibody levels by efgartigimod, a FcRn-antagonist, will ameliorate the underlying immune-mediated pathogenesis and lead to clinical improvements in patients who developed POTS following COVID-19 infection. We propose a phase II multicenter, randomized, placebo-controlled, double-blind, proof-of-mechanism study initiated to evaluate the safety and efficacy of efgartigimod in adults with post–COVID-19 POTS. Methods Adult patients diagnosed with new-onset of POTS following SARS-CoV-2 infection are eligible for participation in the study. Prior COVID-19 must be confirmed by documentation of historical PCR test, and POTS diagnosis must meet consensus criteria. Study subjects must have moderate to severe autonomic symptoms (COMPASS-31 score ≥ 35 points at screening). Approximately 42 patients will be randomly allocated (2:1) to receive weekly intravenous efgartigimod or placebo for 24 weeks. At the end of the treatment period, participants who complete the study may roll over into an open-label extension (OLE). The co-primary endpoints are change from baseline to week 24 in the COMPASS-31 and Malmo POTS Symptom Score as well as safety and tolerability outcomes. Key secondary endpoints include assessments of disease activity, fatigue, cognitive function, walking capacity and quantitative autonomic testing. Additional exploratory endpoints include intraepidermal small fiber densities (optional), sudomotor innervation (optional) and peripheral blood biomarkers to define histopathological and immune determinants associated with treatment response. Conclusions This phase II study of efgartigimod will evaluate the effect of FcRn inhibition on disease pathology and the potential for therapeutic benefit in patients with post–COVID-19 POTS.

Direct IL-6 inhibition prevents arterial thrombosis by reducing collagen-mediated platelets activation

Abstract Introduction Interleukin 6 (IL-6) has a pivotal role in atherothrombosis. Yet, targeting IL-6 to prevent atherothrombotic events still requires validation of efficacy and safety. The recent phase 2 RESCUE trial reported that direct inhibition of IL-6 ligand by the monoclonal antibody (mAb) Ziltivekimab is safe in patients with elevated cardiovascular risk. Purpose This project investigated the effects of direct IL-6 inhibition on arterial thrombosis, and assessed the underlying cellular mechanisms. Methods Three month old C56Bl/6 male mice received very-low dose LPS i.p. for 4 weeks. During the last week they were randomized to receive in addition either anti-mouse IL-6 mAb 200 μg i.p. every other day or IgG1 isotype control. Then thrombosis of left common carotid artery (LCCA) was induced by laser injury under anesthesia. Platelets of treated mice were isolated and stimulated with either adenosine di-phosphate (ADP), collagen-related peptide (CRP) or thrombin receptor activating peptide (TRAP). Platelets activation was measured by flow-cytometry, as expression of P-selectin and JON/A.The effect of direct IL-6 inhibition was confirmed in patients with stable coronary artery disease (sCAD) by ex-vivo incubation of isolated platelets with either anti-human IL-6 mAb 1.5 μg/mL or IgG1 isotype control. Platelet activation was measured by flow-cytometry, as expression of P-selectin. Results Mice treated with anti-IL6 antibody displayed a significantly longer time-to-occlusion after the LCCA (Figure 1), without any significant difference in coagulation parameters. After stimulation with CRP, platelets were significantly activated in control mice, but not in mice treated with anti-IL6 mAb. Similarly, activation of isolated platelets from patients with sCAD was significantly reduced (Figure 2) by the ex-vivo treatment with anti-IL6 mAb. Conclusion The direct inhibition of IL-6 reduces platelets reactivity to collagen, thereby blunting arterial thrombosis upon endothelial damage. These results provide a potential mechanism to explain the reduction of cardiovascular risk associated to direct IL-6 inhibition. Conclusion The direct inhibition of IL-6 reduces platelets reactivity to collagen, thereby blunting arterial thrombosis upon endothelial damage. These results provide a potential mechanism to explain the reduction of cardiovascular risk associated to direct IL-6 inhibition.Figure 1Figure 2

Effects of BET Inhibition on lung micro-environmental changes in obesity-related pulmonary Arterial Hypertension (PAH)

Abstract Background Obesity is emerging as a pivotal risk factor for pulmonary arterial hypertension (PAH) but the underlying molecular mechanisms are poorly explored. The lung microenvironment, namely the cell-cell communication among fibroblasts, immune and endothelial cells, may significantly impact on vascular structure and function thus promoting microvascular disease in this setting. Obesity-induced chromatin modifications lead to maladaptive transcriptional programs altering cell function in different organs. Apabetalone (APA), a selective inhibitor of bromodomain and extra-terminal containing protein family (BET) proteins, prevents bromodomain-containing protein 4 (BRD4) interactions with chromatin thus modulating gene expression. Purpose To determine whether a new epi-drug, namely APA, affects the lung microenvironment in obesity-related PAH. Methods Mice were fed a normal diet (ND, control) or high-fat-diet (HFD) and L-NAME for 15 weeks to induce obesity-related PAH (obPAH). Echocardiography was performed. Pathways regulating obPAH were identified by single-cell nuclei RNA sequencing in lung specimens. Primary endothelial cells (ECs) and Fibroblasts (mFs) were freshly isolated from obPAH lungs and treated with APA for 48 hours. Cells and lung samples were used for molecular biology and histology. Cellular migration was investigated by in vitro gap closure. Results Obese mice displayed PAH as shown by increased pulmonary artery (PA) pressure, PA resistance, right ventricular wall thickness and reduced PA acceleration time. Of note, chronic APA treatment prevented PAH-related features in obese mice. To determine the cell types affected by APA, we performed scRNAseq. We found that fibroblast and endothelial cells had the highest enrichment of genes whose expression significantly correlated with echo-determined PAH features. ECs and mFs from obese mice displayed an altered phenotype whereas treatment with APA rescued obesity-driven ECs and mFs dysfunction. In obPAH ECs, we found increased expression of NF-kB p65-related inflammatory genes (IL-1β, IL-6, TNF-alpha) as well as enhanced p53 signaling. Moreover, obPAH-ECs expressed high levels of hypoxia-inducible factor (HIF1-α) and NADPH-oxidase-NOX4 with subsequent increase in ROS generation. Furthermore, APA treatment protected against cellular inflammation, senescence and oxidative stress. To evaluate the effect of APA and the paracrine response of fibroblasts, we performed a scratch assay on control mFs exposed to TGF-β or conditioned media collected from obPAH-ECs with and without APA. In both experimental settings, APA affected gap closure, suggesting that the treatment influences fibroblast migration through both a direct effect and paracrine mechanisms. Conclusions APA is able to reset the lung micro-envirnment in obesity thus reducing inflammation and senescence. BET inhibitors could represent potential therapeutic approaches in this setting.

Targeting BRD4-HK2 reverses the meta-inflammatory shift in perivascular adipose tissue and rescues cardiometabolic vascular dysfunction

Abstract Background/Introduction Reducing vascular inflammation is crucial to halt and reverse cardiometabolic damage. BRD4, an epigenetic pan-inflammatory activator whose inhibition has shown promising results in cancer, may play an important role in this context. However, its role in cardiometabolic disease remains unclear. Purpose To investigate BRD4-related transcriptional programmes and therapeutic modulation in translational models of cardiometabolic disease. Methods We dissected small arteries (100-300 μM) from visceral fat biopsies in healthy volunteers (n=16) and patients with obesity and hypertension (n=16), a highly prevalent cardiometabolic phenotype. We assessed the ex vivo effects of BRD4 inhibition on vascular function by pressure myography in the presence or absence of perivascular adipose tissue (PVAT), at baseline and after incubation with the BRD4 inhibitor RVX-208 or with anti-inflammatory/anti-metabolic drugs. We used a cardiometabolic mouse model (high-fat diet+L-NAME supplementation) that mirrored our human phenotype and orally administered RVX-208 (150 mg/kg) or vehicle for 5 days (n=6 per group) to confirm the in vivo effect of chronic BRD4 inhibition. Finally, we investigated the molecular pathways involved in the perivascular cross-talk in an in vitro model of human adipocytes (hADSCs) and endothelial cells (HAECs) using gene overexpression/silencing strategies. We assessed ROS and nitric oxide levels (confocal microscopy), protein and gene expressions (Western blot; qPCR), transcriptional (custom qPCR array; chromatin immunoprecipitation (ChIP)) and metabolic changes (metabolomics, lipidomics, mitochondrial swelling). Results Vascular inflammation, remodeling and function were altered in cardiometabolic patients/mice. RVX-208 attenuated ex vivo vascular dysfunction to a greater extent than anti-IL-1β, anti-IL-6 receptor and anti-TNF-α. In vessels with intact PVAT we observed a stronger effect, due to the restoration of healthy PVAT phenotype (Figure 1). In PVAT, Hexokinase-2 (Hk2) - a glycolytic enzyme implicated in mitochondrial dysfunction and inflammation - was the top downregulated gene by RVX-208 treatment; ChIP confirmed increased binding of BRD4 to the Hk2 promoter. In line, metabolomics and lipidomics assays revealed a PVAT glycolytic shift with increased fatty acid storage in disease states, which was reversed by BRD4 inhibition. The in vitro study showed that: i) healthy adipocytes overexpressing HK2 shift to an inflammatory phenotype; ii) their secretome induces an inflammatory phenotype in HAECs; iii) ex vivo PVAT-selective inhibition of HK2 ameliorates vascular dysfunction (Figure 2). Conclusions We identified BRD4-HK2 interaction at the PVAT level as a novel mediator of cardiometabolic damage. Its targeting rescues vascular dysfunction by reversing the PVAT meta-inflammatory shift. Epigenetic modulators of meta-inflammation may represent a promising strategy in patients with obesity and hypertension.

Reduced Na current in dystrophin-deficient ventricular cardiomyocytes is rescued by tenascin-C inhibition

Abstract Background Duchenne muscular dystrophy (DMD) is an X-linked hereditary disease triggered by the deficiency of the structural protein dystrophin, which leads to muscular degeneration mainly affecting young males. Major contributors to early death in DMD patients are cardiac arrhythmias and dystrophic cardiomyopathy. One cause for arrhythmias is impaired ventricular impulse conduction, which leads to ventricular asynchrony and reentrant mechanisms. We recently showed that the disruption of dystrophin results in a significant reduction of Na current in ventricular cardiomyocytes (vCMs) of the dystrophin-deficient mdx mouse model for human DMD. Na current reduction provides a mechanistic explanation for the impaired ventricular conduction and accompanying arrhythmias in the dystrophic heart. The extracellular matrix protein tenascin-C (TN-C) is a significant remodeling factor in the injured and diseased heart and is strongly upregulated in dystrophic cardiomyopathy. To this date, it is unknown how the upregulation of TN-C in DMD patients affects dystrophic cardiomyopathy. Purpose In this study, we examined the effect of TN-C inhibition on diminished Na currents in dystrophin-deficient vCMs. Methods We compared four different mouse genotypes with each other, namely wild-type, dystrophin-deficient mdx, TN-C-deficient and dystrophin- plus TN-C-deficient mice. Furthermore, a cohort of mdx mice was injected with TN-C siRNA twice a week for 9 weeks to investigate the effect of TN-C knockdown. Hearts from adult male mice were enzymatically digested using a Langendorff system to isolate single vCMs. Na currents were then measured with the whole cell patch clamp technique. Results Na current densities were increased in TN-C deficient vCMs compared to wild-type vCMs. Accordingly, 24-hour incubation of wild-type vCMs with human recombinant TN-C resulted in a significant decrease in Na current. Na currents of vCMs from mdx mice were reduced, but restored to the wild-type level in vCMs from TN-C-deficient mdx mice. Moreover, vCMs of TN-C siRNA-treated mdx mice had significantly increased Na currents compared to control mdx vCMs. Conclusion Upregulation of TN-C in dystrophin-deficient vCMs reduces Na currents, whereas inhibition of TN-C prevents this reduction. Therefore, inhibition of TN-C in DMD patients may be considered as a potential new therapeutic strategy to improve ventricular conduction and reduce arrhythmia vulnerability.

Beneficial effects of the SGLT2 inhibition on oxidative skeletal muscle in infarcted rats

Abstract Introduction Metabolic, morphological, and biochemical changes in skeletal muscle are common in chronic heart failure patients. Despite the cardioprotective effects of sodium-glucose co-transporter 2 (SGLT2) inhibition in heart failure, the impact of this drug on skeletal muscle remains poorly understood. This study investigated the effects of SGLT2 inhibitor empagliflozin (EMPA) on the soleus muscle of rats with myocardial infarction (MI)-induced heart failure. Methods One week after MI induction, male Wistar rats were divided into Sham (n=10), Sham+EMPA (n=12), MI (n=10) and MI+EMPA (n=09) groups. EMPA was added to rat chow (5 mg/kg/day) for 12 weeks. Cardiac remodeling was evaluated by echocardiogram. Enzymatic activity and oxidative stress marker concentrations were assessed by spectrophotometry; protein expression was evaluated by Western blotting. After histological analysis of the left ventricle (LV), only rats with MI greater than 35% of total LV area were included in the study. Statistical analysis: ANOVA and Tukey or Kruskal–Wallis and Dunn and t test; p<0.05. Results Infarction size did not differ between groups. Infarcted groups had larger LV systolic and diastolic diameters, LV diastolic area (Sham 47±7.1; Sham+EMPA 48±4.5; MI 100±16.1*; MI+EMPA 85±10.1#† mm2; p<0.05: * vs Sham; # vs Sham+EMPA; † vs MI), and left atrial diameter (Sham 5.62±0.2; Sham+EMPA 5.65±0.3; MI 7.69±1.3*; MI+EMPA 6.85±0.9#† mm; p<0.05: * vs Sham; # vs Sham+EMPA; † vs MI); and lower LV posterior wall shortening velocity and ejection fraction than control groups. Echocardiographic changes were attenuated in MI+EMPA compared to MI. Other results are shown in Picture 1. Conclusion SGLT2 inhibitor empagliflozin attenuates infarction-induced cardiac remodeling in rats. Empagliflozin prevents increase in oxidative stress, modulates protein turnover by IGF-1 pathway, and attenuates morphological and biochemical changes in the soleus muscle of infarcted rats.

Assessing the effects of HMGCR, LPL, and PCSK9 inhibition on sleep apnea: Mendelian randomization analysis of drug targets.

To investigate the use of lipid-lowering drugs and abnormal serum lipid levels in patients at risk of sleep apnea syndrome. Three types of Mendelian randomization (MR) analyses were used. First, a 2-sample Mendelian randomization (TSMR) analysis was used to investigate the association between sleep apnea syndrome risk and serum lipid levels. Multivariate Mendelian randomization (MVMR) analysis was subsequently used to investigate the effects of confounding variables on SAS incidence of sleep apnea syndrome. Finally, drug-target Mendelian randomization (DMR) analysis was used to analyze the association between lipid-lowering drug use and sleep apnea syndrome risk. According to the TSMR analysis, the serum HDL-C concentration was negatively correlated with sleep apnea syndrome (OR = 0.904; 95% CI = 0.845-0.967; P = .003). Serum TG levels were positively correlated with sleep apnea syndrome (OR = 1.081; 95% CI = 1.003-1.163; P = .039). The association between serum HDL-C levels and sleep apnea syndrome in patients with MVMR was consistent with the results in patients with TSMR (OR = 0.731; 95% CI = 0.500-1.071; P = 3.94E-05). According to our DMR analysis, HMGCR and PCSK9, which act by lowering serum LDL-C levels, were inversely associated with the risk of sleep apnea syndrome (OR = 0.627; 95% CI = 0.511-0.767; P = 6.30E-06) (OR = 0.775; 95% CI = 0.677-0.888; P = .0002). LPL, that lowered serum TG levels, was positively associated with the risk of sleep apnea syndrome (OR = 1.193; 95% CI = 1.101-1.294; P = 1.77E-05). Our analysis suggested that high serum HDL-C levels may reduce the risk of sleep apnea syndrome. Low serum TG levels have a protective effect against sleep apnea syndrome. The DMR results suggested that the use of HMGCR lipid-lowering drugs (such as statins) and PCSK9 inhibitors has a protective effect against sleep apnea syndrome. However, LPL-based lipid-lowering drugs may increase the risk of sleep apnea syndrome.

Pharmacological inhibition of histamine N-methyltransferase extends wakefulness and suppresses cataplexy in a mouse model of narcolepsy.

Histamine, a neurotransmitter, plays a predominant role in maintaining wakefulness. Further, our previous studies showed that histamine N-methyltransferase (HNMT), a histamine-metabolising enzyme, is important for regulating brain histamine concentration. However, the effects of pharmacological HNMT inhibition on mouse behaviour, including the sleep-wake cycle and cataplexy, in a mouse model of narcolepsy have not yet been investigated. In the present study, we investigated the effects of metoprine, an HNMT inhibitor with high blood-brain barrier permeability, in wild-type (WT) and orexin-deficient (OxKO) narcoleptic mice. Metoprine increased brain histamine concentration in a time- and dose-dependent manner without affecting peripheral histamine concentrations. Behavioural tests showed that metoprine increased locomotor activity in both novel and familiar environments, but did not alter anxiety-like behaviour. Sleep analysis showed that metoprine increased wakefulness and decreased non-rapid eye movement (NREM) sleep through the activation of the histamine H1 receptor (H1R) in WT mice. In contrast, the reduction of rapid eye movement (REM) sleep by metoprine occurred independent of H1R. In OxKO mice, metoprine was found to prolong wakefulness and robustly suppress cataplexy. In addition, metoprine has a greater therapeutic effect on cataplexy than pitolisant, which induces histamine release in the brain, and has been approved for patients with narcolepsy. These data demonstrate that HNMT inhibition has a strong effect on wakefulness, demonstrating therapeutic potential against cataplexy in narcolepsy.

Combining ERAP1 silencing and entinostat therapy to overcome resistance to cancer immunotherapy in neuroblastoma

BackgroundCheckpoint immunotherapy unleashes tumor control by T cells, but it is undermined in non-immunogenic tumors, e.g. with low MHC class I expression and low neoantigen burden, such as neuroblastoma (NB). Endoplasmic reticulum aminopeptidase 1 (ERAP1) is an enzyme that trims peptides before loading on MHC class I molecules. Inhibition of ERAP1 results in the generation of new antigens able of inducing potent anti-tumor immune responses. Here, we identify a novel non-toxic combinatorial strategy based on genetic inhibition of ERAP1 and administration of the HDAC inhibitor (HDACi) entinostat that increase the immunogenicity of NB, making it responsive to PD-1 therapy.MethodsCRISPR/Cas9-mediated gene editing was used to knockout (KO) the ERAP1 gene in 9464D NB cells derived from spontaneous tumors of TH-MYCN transgenic mice. The expression of MHC class I and PD-L1 was evaluated by flow cytometry (FC). The immunopeptidome of these cells was studied by mass spectrometry. Cocultures of splenocytes derived from 9464D bearing mice and tumor cells allowed the assessment of the effect of ERAP1 inhibition on the secretion of inflammatory cytokines and activation and migration of immune cells towards ERAP1 KO cells by FC. Tumor cell killing was evaluated by Caspase 3/7 assay and flow cytometry analysis. The effect of ERAP1 inhibition on the immune content of tumors was analyzed by FC, immunohistochemistry and multiple immunofluorescence.ResultsWe found that inhibition of ERAP1 makes 9464D cells more susceptible to immune cell-mediated killing by increasing both the recall and activation of CD4+ and CD8+ T cells and NK cells. Treatment with entinostat induces the expression of MHC class I and PD-L1 molecules in 9464D both in vitro and in vivo. This results in pronounced changes in the immunopeptidome induced by ERAP1 inhibition, but also restrains the growth of ERAP1 KO tumors in vivo by remodelling the tumor-infiltrating T-cell compartment. Interestingly, the absence of ERAP1 in combination with entinostat and PD-1 blockade overcomes resistance to PD-1 immunotherapy and increases host survival.ConclusionsThese findings demonstrate that ERAP1 inhibition combined with HDACi entinostat treatment and PD-1 blockade remodels the immune landscape of a non-immunogenic tumor such as NB, making it responsive to checkpoint immunotherapy.

Blockade of brain alkaline phosphatase efficiently reduces amyloid-β plaque burden and associated cognitive impairment

BackgroundAlzheimer’s disease (AD) is the most prevalent neurodegenerative disease. Three new drugs for AD based on monoclonal antibodies against the amyloid-β peptide (Aβ) have recently been approved because they favor the reduction of the burden of senile plaque in the AD patient’s brain. Nonetheless, both drugs have very limited applicability and benefits and show several side effects. These limitations invite us to find alternative strategies for treating patients with AD. Here, we explored whether tissue-nonspecific alkaline phosphatase (TNAP), an ectoenzyme upregulated in the brain of AD patients and whose inhibition has beneficial effects on tau-induced pathology, is also efficient in reducing senile plaque burden.MethodsTo evaluate whether TNAP may reduce cerebral senile plaque loading and Aβ-related toxicity, we use both pharmacological and genetic approaches. We analyze postmortem samples from human AD patients, APP/PS1 mice (a mouse model that mimics amyloid pathology observed in AD patients) treated or not with TNAP inhibitors, and the newly generated transgenic mouse line, TNAP-deficient APP/PS1 mice.ResultsFor the first time, we describe that genetic or pharmacological blockade of TNAP effectively reduces senile plaque burden by promoting its clearance, which leads to amelioration of cognitive impairment caused by Aβ-induced toxicity. These beneficial effects of TNAP inhibition occur concomitantly with higher microglial recruitment toward the senile plaque and increased microglial phagocytic capacity of Aβ by a mechanism involving metalloprotease-depending osteopontin processing. In addition, we also found that TNAP blockade favors LRP1-mediated transport of Aβ through the BBB.ConclusionsHere, we have shown that TNAP inhibition effectively reduces brain senile plaque burden and associated behavioral defects. Furthermore, given that we had previously reported that TNAP blockade also ameliorates Tau-induced neurotoxicity and increases lifespan of P301S tauopathy mouse model, we can state that TNAP blockade may be a novel and efficient therapy for treating patients with AD.

MEK inhibition prevents CAR-T cell exhaustion and differentiation via downregulation of c-Fos and JunB

Clinical evidence supports the notion that T cell exhaustion and terminal differentiation pose challenges to the persistence and effectiveness of chimeric antigen receptor-T (CAR-T) cells. MEK1/2 inhibitors (MEKIs), widely used in cancer treatment due to their ability to inhibit aberrant MAPK signaling, have shown potential synergistic effects when combined with immunotherapy. However, the impact and mechanisms of MEKIs on CAR-T cells remain uncertain and controversial. To address this, we conducted a comprehensive investigation to determine whether MEKIs enhance or impair the efficacy of CAR-T cells. Our findings revealed that MEKIs attenuated CAR-T cell exhaustion and terminal differentiation induced by tonic signaling and antigen stimulation, thereby improving CAR-T cell efficacy against hematological and solid tumors. Remarkably, these effects were independent of the specific scFvs and costimulatory domains utilized in CARs. Mechanistically, analysis of bulk and single-cell transcriptional profiles demonstrates that the effect of MEK inhibition was related to diminish anabolic metabolism and downregulation of c-Fos and JunB. Additionally, the overexpression of c-Fos or JunB in CAR-T cells counteracted the effects of MEK inhibition. Furthermore, our Cut-and-Tag assay revealed that MEK inhibition downregulated the JunB-driven gene profiles associated with exhaustion, differentiation, anergy, glycolysis, and apoptosis. In summary, our research unveil the critical role of the MAPK-c-Fos-JunB axis in driving CAR-T cell exhaustion and terminal differentiation. These mechanistic insights significantly broaden the potential application of MEKIs to enhance the effectiveness of CAR-T therapy.

Genetic iron overload aggravates and pharmacological iron restriction improves MDS pathophysiology in preclinical study

Although iron overload is a common feature in myelodysplastic syndromes (MDS), it remains unclear how iron excess is detrimental for disease pathophysiology. Taking advantage of complementary approaches, we analyzed the impact of iron overload and restriction achieved through genetic activation (FPNC326S) and pharmacologic inhibition (vamifeport) of the iron exporter ferroportin in a MDS mouse model, respectively. While FPNC326S-induced iron overload did not significantly improve the late stages of erythroid maturation, vamifeport-mediated iron restriction ameliorated anemia and red blood cell maturation in MDS mice, through the reduction of oxidative stress and apoptosis in erythroid progenitors. Iron overload aggravated and restriction alleviated ROS formation, DNA damage and cell death in hematopoietic stem and progenitor cells, resulting in altered cell survival and quality. Finally, myeloid bias, indicated by expanded bone marrow myeloid progenitors and circulating immature myeloid blasts, was exacerbated by iron excess and attenuated by iron restriction. Overall, vamifeport treatment resulted in improved anemia and significant survival increment in MDS mice. Interestingly, the combined therapy with vamifeport and the erythroid maturation agent luspatercept has superior effect in improving anemia and myeloid bias as compared to single treatments, and offers additive beneficial effects in MDS. Our results prove for the first time in a preclinical model that iron plays a pathologic role in transfusion-independent MDS. This is likely aggravated by transfusional iron overload, as suggested by observations in the FPNC326SMDS model. Ultimately, the beneficial effects of pharmacologic FPN inhibition uncovers the therapeutic potential of early prevention of iron toxicity in transfusion-independent MDS.

Optimizing pectin lyase production using the one-factor-at-a-time method and response surface methodology.

Pectinases are commonly industrially synthesized by molds. This study aimed to optimize pectin lyase synthesis by a bacterium, Pseudomonas fluorescens, using both the one-factor-at-a-time (OFAT) method and response surface methodology. First, on optimization of pectin lyase fermentation by the OFAT method, the effects of pectin, peptone, yeast extract, (NH4)2SO4, pH, and salts were investigated. The highest pectin lyase activity was determined to be 28.63U/mL at pH 8, 30°C, with 1% (w/v) pectin and 0.14% (w/v) (NH4)2SO4 concentration at the 90th hour. The effect of substrate inhibition on the microbial growth was also investigated, and the results showed that the process can be described by noncompetitive inhibition model. The values of kinetic constants were determined as µm=0.175h-1, KS=6.931g/L, and, KI=6.932g/L by nonlinear regression analysis. It was reported that pectin lyase enzymes exhibited peak activity at 50°C and pH 8. Finally, response surface methodology (RSM) was utilized to optimize pH, concentrations of ammonium sulfate, and pectin, which were chosen as independent variables. The interactions between these variables were also examined. According to RSM, the optimum values of the parameters to achieve a maximum pectin lyase activity of 35.62U/mL were determined to be pH 7.97, 1.25% (w/v) pectin concentration, and 0.25% (w/v) (NH4)2SO4 concentration.

TBK1 is involved in M-CSF-induced macrophage polarization through mediating the IRF5/IRF4 axis.

TANK binding kinase 1 (TBK1) is an important kinase that is involved in innate immunity and tumor development. Macrophage colony-stimulating factor (M-CSF) regulates the differentiation and function of macrophages towards the immunosuppressive M2 phenotype in the glioblastoma multiforme microenvironment. The role of TBK1 in macrophages, especially in regulating macrophage polarization in response to M-CSF stimulation, remains unclear. Here, we found high TBK1 expression in human glioma-infiltrating myeloid cells and that phosphorylated TBK1 was highly expressed in M-CSF-stimulated macrophages but not in granulocyte-macrophage CSF-induced macrophages (granulocyte-macrophage-CSF is involved in the polarization of M1 macrophages). Conditional deletion of TBK1 in myeloid cells induced M-CSF-stimulated bone marrow-derived macrophages to exhibit a proinflammatory M1-like phenotype with increased protein expression of CD86, interleukin-1β and tumor necrosis factor-α, as well as decreased expression of arginase 1. Mechanistically, TBK1 deletion or inhibition by amlexanox or GSK8612 reduced the expression of the transcription factor interferon-regulatory factor (IRF)4 and increased the level of IRF5 activation in macrophages stimulated with M-CSF, leading to an M1-like profile with highly proinflammatory factors. IRF5 deletion reversed the effect of TBK1 inhibition on M-CSF-mediated macrophage polarization. Our findings suggest that TBK1 contributes to the regulation of macrophage polarization in response to M-CSF stimulation partly through the IRF5/IRF4 axis.

Ferroptosis Mediated Inflammation Promotes Pulmonary Hypertension.

Mitochondrial dysfunction, characterized by impaired lipid metabolism and heightened reactive oxygen species generation, results in lipid peroxidation and ferroptosis. Ferroptosis is an inflammatory mode of cell death that promotes complement activation and macrophage recruitment. In pulmonary arterial hypertension (PAH), pulmonary arterial endothelial cells exhibit cellular phenotypes that promote ferroptosis. Moreover, there is ectopic complement deposition and inflammatory macrophage accumulation in the pulmonary vasculature. However, the effects of ferroptosis inhibition on these pathogenic mechanisms and the cellular landscape of the pulmonary vasculature are incompletely defined. Multiomics and physiological analyses evaluated how ferroptosis inhibition-modulated preclinical PAH. The impact of adeno-associated virus 1-mediated expression of the proferroptotic protein ACSL (acyl-CoA synthetase long-chain family member) 4 on PAH was determined, and a genetic association study in humans further probed the relationship between ferroptosis and pulmonary hypertension. Ferrostatin-1, a small-molecule ferroptosis inhibitor, mitigated PAH severity in monocrotaline rats. RNA-sequencing and proteomics analyses demonstrated that ferroptosis was associated with PAH severity. RNA-sequencing, proteomics, and confocal microscopy revealed that complement activation and proinflammatory cytokines/chemokines were suppressed by ferrostatin-1. In addition, ferrostatin-1 combatted changes in endothelial, smooth muscle, and interstitial macrophage abundance and gene activation patterns as revealed by deconvolution RNA-sequencing. Ferroptotic pulmonary arterial endothelial cell damage-associated molecular patterns restructured the transcriptomic signature and mitochondrial morphology, promoted the proliferation of pulmonary artery smooth muscle cells, and created a proinflammatory phenotype in monocytes in vitro. Adeno-associated virus 1-Acsl4 induced an inflammatory PAH phenotype in rats. Finally, single-nucleotide polymorphisms in 6 ferroptosis genes identified a potential link between ferroptosis and pulmonary hypertension severity in the Vanderbilt BioVU repository. Ferroptosis promotes PAH through metabolic and inflammatory mechanisms in the pulmonary vasculature.

Ultrasound-triggered and glycosylation inhibition-enhanced tumor piezocatalytic immunotherapy.

Nanocatalytic immunotherapy holds excellent potential for future cancer therapy due to its rapid activation of the immune system to attack tumor cells. However, a high level of N-glycosylation can protect tumor cells, compromising the anticancer immunity of nanocatalytic immunotherapy. Here, we show a 2-deoxyglucose (2-DG) and bismuth ferrite co-loaded gel (DBG) scaffold for enhanced cancer piezocatalytic immunotherapy. After the implantation in the tumor, DBG generates both reactive oxygen species (ROS) and piezoelectric signals when excited with ultrasound irradiation, significantly promoting the activation of anticancer immunity. Meanwhile, 2-DG released from ROS-sensitive DBG disrupts the N-glycans synthesis, further overcoming the immunosuppressive microenvironment of tumors. The synergy effects of ultrasound-triggered and glycosylation inhibition enhanced tumor piezocatalytic immunotherapy are demonstrated on four mouse cancer models. A "hot" tumor-immunity niche is produced to inhibit tumor progress and lung metastasis and elicit strong immune memory effects. This work provides a promising piezocatalytic immunotherapy for malignant solid tumors featuring both low immunogenicity and high levels of N-glycosylation.

Autophagy is required for mammary tumor recurrence by promoting dormant tumor cell survival following therapy

BackgroundMortality from breast cancer is principally due to tumor recurrence. Recurrent breast cancers arise from the pool of residual tumor cells, termed minimal residual disease, that survive treatment and may exist in a dormant state for 20 years or more following treatment of the primary tumor. As recurrent breast cancer is typically incurable, understanding the mechanisms underlying dormant tumor cell survival is a critical priority in breast cancer research. The importance of this goal is further underscored by emerging evidence suggesting that targeting dormant residual tumor cells in early-stage breast cancer patients may be a means to prevent tumor recurrence and its associated mortality. In this regard, the role of autophagy in dormant tumor cell survival and recurrence remains unresolved, with conflicting reports of both pro-survival/recurrence-promoting and pro-death/recurrence-suppressing effects of autophagy inhibition in dormant tumor cells. Resolving this question has important clinical implications.MethodsWe used genetically engineered mouse models that faithfully recapitulate key features of human breast cancer progression, including minimal residual disease, tumor dormancy, and recurrence. We used genetic and pharmacological approaches to inhibit autophagy, including treatment with chloroquine, genetic knockdown of ATG5 or ATG7, or deletion of BECN and determined their effects on dormant tumor cell survival and recurrence.ResultsWe demonstrate that the survival and recurrence of dormant mammary tumor cells following therapy is dependent upon autophagy. We find that autophagy is induced in vivo following HER2 downregulation and remains activated in dormant residual tumor cells. Using genetic and pharmacological approaches we show that inhibiting autophagy by chloroquine administration, ATG5 or ATG7 knockdown, or deletion of a single allele of the tumor suppressor Beclin 1 is sufficient to inhibit mammary tumor recurrence, and that autophagy inhibition results in the death of dormant mammary tumor cells in vivo.ConclusionsOur findings demonstrate a pro-tumorigenic role for autophagy in tumor dormancy and recurrence following therapy, reveal that dormant tumor cells are uniquely reliant upon autophagy for their survival, and indicate that targeting dormant residual tumor cells by inhibiting autophagy impairs tumor recurrence. These studies identify a pharmacological target for a cellular state that is resistant to commonly used anti-neoplastic agents and suggest autophagy inhibition as an approach to reduce dormant minimal residual disease in order to prevent lethal tumor recurrence.