A critical role for palmitoylation in pyroptosis.

Three recent publications by Du et al.,1 Balasubramanian et al.,2 and Zhang et al.3 identified palmitoylation on cysteine 191/192 in gasdermin D as a key determinant of gasdermin D membrane translocation and oligomerization, ensuring efficient plasma membrane permeabilization during pyroptosis.

Comparison of intravascular ultrasound-guided with angiography-guided double kissing crush stenting for patients with complex coronary bifurcation lesions: Rationale and design of a prospective, randomized, and multicenter DKCRUSH VIII trial.

BACKGROUND: Double kissing (DK) crush approach for patients with coronary bifurcation lesions, particularly localized at distal left main or lesions with increased complexity, is associated with significant reduction in clinical events when compared with provisional stenting. Recently, randomized clinical trial has demonstrated the net clinical benefits by intravascular ultrasound (IVUS)-guided implantation of drug-eluting stent in all-comers. However, the improvement in clinical outcome after DK crush treatment guided by IVUS over angiography guidance for patients with complex bifurcation lesions have never been studied in a randomized fashion. TRIAL DESIGN: DKCRUSH VIII study is a prospective, multicenter, randomized controlled trial designed to assess superiority of IVUS-guided vs angiography-guided DK crush stenting in patients with complex bifurcation lesions according to DEFINITION criteria. A total of 556 patients with complex bifurcation lesions will be randomly (1:1 of ratio) assigned to IVUS-guided or angiography-guided DK crush stenting group. The primary end point is the rate of 12-month target vessel failure, including cardiac death, target vessel myocardial infarction, or clinically driven target vessel revascularization. The secondary end points consist of the individual component of primary end point, all-cause death, myocardial infarction, and in-stent restenosis. The safety end point is the incidence of definite or probable stent thrombosis. An angiographic follow-up will be performed for all patients at 13 months and clinical follow-up will be continued annually until 3 years after the index procedure. CONCLUSIONS: DKCRUSH VIII trial is the first study designed to evaluate the differences in efficacy and safety between IVUS-guided and angiography-guided DK crush stenting in patients with complex true bifurcation lesions. This study will also provide IVUS-derived criteria to define optimal DK crush stenting for bifurcation lesions at higher complexity.

Protease-activated receptor signalling initiates α5ß1-integrin-mediated adhesion in non-haematopoietic cells.

Haematopoietic cells and platelets employ G-protein-coupled receptors (GPCRs) to sense extracellular information and respond by initiating integrin-mediated adhesion. So far, such processes have not been demonstrated in non-haematopoietic cells. Here, we report that the activation of protease-activated receptors PAR1 and PAR2 induce multiple signalling pathways to establish α5ß1-integrin-mediated adhesion. First, PARs signal via Gßγ and PI3K to α5ß1-integrins to adopt a talin- and kindlin-dependent high-affinity conformation, which triggers fibronectin binding and initiates cell adhesion. Then, within 60 s, PARs signal via Gα13, Gαi, ROCK and Src to strengthen the α5ß1-integrin-mediated adhesion. Furthermore, PAR signalling changes the abundance of numerous proteins in the adhesome assembled by α5ß1-integrins, including Gα13, vacuolar protein-sorting-associated protein 36, and band 4.1-like protein 4B or 5, and accelerates cell adhesion maturation, spreading and migration. The mechanistic insights describe how agonist binding to PAR employs GPCR and integrin-signalling pathways to initiate and regulate adhesion and to guide physiological responses of non-haematopoietic cells.

A firm grip does not always pay off: a new Phact(r) 4 integrin signaling.

ß1 integrin signaling plays crucial roles in enteric nervous system development. Zhang and colleagues (pp. 69-81) discovered that phosphatase and actin regulator 4 (Phactr4) antagonizes ß1 integrin signaling through protein phosphatase 1 (PP1) in focal adhesions of enteric neural crest cells (ENCCs). Loss of Phactr4-PP1 interaction leads to increased ß1 integrin signaling, loss of collective and directional migration, and hindgut hypogangaliosis, indicating that the right adjustment of ß1 integrin signaling is required for the normal migration and organization of ENCCs.

Effective dosing of L-carnitine in the secondary prevention of cardiovascular disease: a systematic review and meta-analysis.

BACKGROUND: L-carnitine supplementation has been associated with a significant reduction in all-cause mortality, ventricular arrhythmia, and angina in the setting of acute myocardial infarction (MI). However, on account of strict homeostatic regulation of plasma L-carnitine concentrations, higher doses of L-carnitine supplementation may not provide additional therapeutic benefits. This study aims to evaluate the effects of various oral maintenance dosages of L-carnitine on all-cause mortality and cardiovascular morbidities in the setting of acute MI. METHODS: After a systematic review of several major electronic databases (PubMed, EMBASE, and the Cochrane Library) up to November 2013, a meta-analysis of five controlled trials (n = 3108) was conducted to determine the effects of L-carnitine on all-cause mortality and cardiovascular morbidities in the setting of acute MI. RESULTS: The interaction test yielded no significant differences between the effects of the four daily oral maintenance dosages of L-carnitine (i.e., 2 g, 3 g, 4 g, and 6 g) on all-cause mortality (risk ratio [RR] = 0.77, 95% CI [0.57-1.03], P = 0.08) with a statistically insignificant trend favoring the 3 g dose (RR = 0.48) over the lower 2 g dose (RR = 0.62), which was favored over the higher 4 g and 6 g doses (RR = 0.78, 0.78). There was no significant differences between the effects of the daily oral maintenance dosages of 2 g and 6 g on heart failure (RR = 0.53, 95% CI [0.25-1.13], P = 0.10), unstable angina (RR = 0.90, 95% CI [0.51-1.58], P = 0.71), or myocardial reinfarction (RR = 0.74, 95% CI [0.30-1.80], P = 0.50). CONCLUSIONS: There appears to be no significant marginal benefit in terms of all-cause mortality, heart failure, unstable angina, or myocardial reinfarction in the setting of acute MI for oral L-carnitine maintenance doses of greater or less than 3 g per day.

Ligand and structure based hierarchical virtual screening cascade for finding novel epidermal growth factor receptor inhibitors.

The epidermal growth factor receptor (EGFR) tyrosine kinase plays an important role in tumor formation and growth by mediating cell growth and other physiological processes. Therefore, EGFR is a promising target for the treatment of cancer. In this work, we combined ligand-based and structure-based virtual screening methods to identify novel EGFR inhibitors from a library of more than 103 thousand compounds. We first obtained hundreds of compounds with similar physiochemical properties through 3D molecular shape and electrostatic similarity screening with potent inhibitors AEE788 and Afatinib as queries. Next, we identified compounds with strong binding affinities to the EGFR pocket through molecular docking, which makes good use of the structure information of the receptor. After molecular scaffold analysis, our bioassay confirmed 13 compounds with EGFR inhibitory activity and three compounds had IC50 values below 1000 nM. In addition, we collected 5371 EGFR inhibitors from online databases, and clustered them into 7 groups by K-means method using their ECFP4 fingerprints as input. Each cluster had typical molecular fragments and corresponding activity characteristics, which could guide the design of EGFR inhibitors, and we concluded that the fragments from some of the hits are indicated in the highly active scaffolds.

Discovery of benzo[c]phenanthridine derivatives with potent activity against multidrug-resistant Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb), the pathogen responsible for tuberculosis (TB), is the leading cause of bacterial disease-related death worldwide. Current antibiotic regimens for the treatment of TB remain dated and suffer from long treatment times as well as the development of drug resistance. As such, the search for novel chemical modalities that have selective or potent anti-Mtb properties remains an urgent priority, particularly against multidrug-resistant (MDR) Mtb strains. Herein, we design and synthesize 35 novel benzo[c]phenanthridine derivatives (BPDs). The two most potent compounds, BPD-6 and BPD-9, accumulated within the bacterial cell and exhibited strong inhibitory activity (MIC90 ~2 to 10 µM) against multiple Mycobacterium strains while remaining inactive against a range of other Gram-negative and Gram-positive bacteria. BPD-6 and BPD-9 were also effective in reducing Mtb survival within infected macrophages, and BPD-9 reduced the burden of Mycobacterium bovis BCG in the lungs of infected mice. The two BPD compounds displayed comparable efficacy to rifampicin (RIF) against non-replicating Mtb (NR-Mtb). Importantly, BPD-6 and BPD-9 inhibited the growth of multiple MDR Mtb clinical isolates. Generation of BPD-9-resistant mutants identified the involvement of the Mmr efflux pump as an indirect resistance mechanism. The unique specificity of BPDs to Mycobacterium spp. and their efficacy against MDR Mtb isolates suggest a potential novel mechanism of action. The discovery of BPDs provides novel chemical scaffolds for anti-TB drug discovery.IMPORTANCEThe emergence of drug-resistant tuberculosis (TB) is a serious global health threat. There remains an urgent need to discover new antibiotics with unique mechanisms of action that are effective against drug-resistant Mycobacterium tuberculosis (Mtb). This study shows that novel semi-synthetic compounds can be derived from natural compounds to produce potent activity against Mtb. Importantly, the identified compounds have narrow spectrum activity against Mycobacterium species, including clinical multidrug-resistant (MDR) strains, are effective in infected macrophages and against non-replicating Mtb (NR-Mtb), and show anti-mycobacterial activity in mice. These new compounds provide promising chemical scaffolds to develop potent anti-Mtb drugs of the future.

Triglyceride-glucose index as a potential predictor of major adverse cardiovascular and cerebrovascular events in patients with coronary heart disease complicated with depression.

Background: Triglyceride-glucose (TyG) index is a surrogate marker of insulin resistance and metabolic abnormalities, which is closely related to the prognosis of a variety of diseases. Patients with both CHD and depression have a higher risk of major adverse cardiovascular and cerebrovascular events (MACCE) and worse outcome. TyG index may be able to predict the adverse prognosis of this special population. Methods: The retrospective cohort study involved 596 patients with both CHD and depression between June 2013 and December 2023. The primary outcome endpoint was the occurrence of MACCE, including all-cause death, stroke, MI and emergent coronary revascularization. The receiver operating characteristic (ROC) curve, Cox regression analysis, Kaplan-Meier survival analysis, and restricted cubic spline (RCS) analysis were used to assess the correlation between TyG index and MACCE risk of in patients with CHD complicated with depression. Results: With a median follow-up of 31 (15-62) months, MACCE occurred in 281(47.15%) patients. The area under the ROC curve of TyG index predicting the risk of MACCE was 0.765(0.726-0.804) (P<0.01). Patients in the high TyG index group(69.73%) had a significantly higher risk of developing MACCE than those in the low TyG index group(23.63%) (P<0.01). The multifactorial RCS model showed a nonlinear correlation (nonlinear P<0.01, overall P<0.01), with a critical value of 8.80 for the TyG index to predict the occurrence of MACCE. The TyG index was able to further improve the predictive accuracy of MACCE. Conclusions: TyG index is a potential predictor of the risk of MACCE in patients with CHD complicated with depression.

[Feasibility and outcome of rotational atherectomy for treating resistant chronic total occlusions].

OBJECTIVE: To assess the application of rotational atherectomy to improving the success rate and outcome of percutaneous recanalization of resistant chronic total occlusion (CTO), i.e. the guidewire could cross the lesion but it is impossible to advance any device over the wire through the occluded segment. METHODS: From August 2008 to December 2012, 26 consecutive patients with 27 resistant CTO lesions were additionally treated by high-speed rotational atherectomy (rotational atherectomy group). The control group included 751 non-resistant CTO lesions. Drug-eluting stents were implanted in two groups after the balloon catheter crossed the CTO lesions. The successful rate of rotational atherectomy and in hospital major adverse cardiovascular events (including cardiac death, interventional treatment related myocardial infarction and target vessel revascularization) were observed. RESULTS: The rate of heavily calcified coronary lesions was significantly higher in rotational atherectomy group than in the control group[63.0% (17/27) vs. 21.2% (159/751), P < 0.05] according to pre-procedural coronary angiography. Rotational atherectomy was successful in 25 out of 27 resistant CTO lesions (92.6 %). The rate of cardiac death [0 vs. 0.5% (4/751), P > 0.05], interventional treatment related myocardial infarction [38.5% (10/26) vs. 22.2% (167/751), P > 0.05] and target vessel revascularization [0 vs. 1.2% (9/751), P > 0.05] were similar between the rotational atherectomy group and the control group. CONCLUSION: Rotational atherectomy is a safe and helpful technique to overcome the inability of balloon catheter to cross a resistant CTO.

ß1 integrin signaling governs necroptosis via the chromatin-remodeling factor CHD4.

Fibrosis, characterized by sustained activation of myofibroblasts and excessive extracellular matrix (ECM) deposition, is known to be associated with chronic inflammation. Receptor-interacting protein kinase 3 (RIPK3), the central kinase of necroptosis signaling, is upregulated in fibrosis and contributes to tumor necrosis factor (TNF)-mediated inflammation. In bile-duct-ligation-induced liver fibrosis, we found that myofibroblasts are the major cell type expressing RIPK3. Genetic ablation of ß1 integrin, the major profibrotic ECM receptor in fibroblasts, not only abolished ECM fibrillogenesis but also blunted RIPK3 expression via a mechanism mediated by the chromatin-remodeling factor chromodomain helicase DNA-binding protein 4 (CHD4). While the function of CHD4 has been conventionally linked to the nucleosome-remodeling deacetylase (NuRD) and CHD4-ADNP-HP1(ChAHP) complexes, we found that CHD4 potently repressed a set of genes, including Ripk3, with high locus specificity but independent of either the NuRD or the ChAHP complex. Thus, our data uncover that ß1 integrin intrinsically links fibrotic signaling to RIPK3-driven inflammation via a novel mode of action of CHD4.

cGAS-STING signaling.

Cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING, also known as TMEM173) constitute the major signaling pathway in vertebrates that senses non-self DNA and elicits potent immune responses. At the core of this pathway, cGAS senses double-stranded DNA (dsDNA) and synthesizes cyclic GMP-AMP (cGAMP). cGAMP serves as a second messenger that relays its signal to downstream innate immune responses through STING. One of the major consequences triggered by the cGAS-STING pathway is the production of antiviral cytokines of the type I interferon family, which in turn induce expression of hundreds of interferon-stimulated genes (ISGs) with diverse antiviral functions. Recent studies have also revealed functional homologs across phylogenetic kingdoms with innate defense functions, suggesting an ancient evolutionary origin of cGAS-STING signaling. Aberrant activation of the cGAS-STING pathway by host DNA can lead to sterile inflammation associated with tissue damage, degeneration as well as premature aging. In this primer, we will introduce the basic principles of cGAS-STING signaling in the vertebrate system and highlight recent discoveries regarding its connection to other fundamental cellular processes in the context of human diseases.

Design and Rationale of Targeted Therapy With a Sirolimus-Eluting, Biodegradable Polymer Coronary Stent in Chronic Total Occlusions (TARGET CTO): A Multicenter, Open-Label, Randomized Noninferiority Trial.

Background: Treatment of chronic total occlusions (CTOs) is referred to as the last frontier of percutaneous coronary interventions and is currently performed in 10% to 20% of procedures. Improved outcomes with newer generation drug-eluting stents require further research. Methods: The TARGET CTO trial (NCT03040934) is a prospective, multicenter, randomized, noninferiority trial that plans to randomize 196 subjects (1:1) to either a newer-generation sirolimus target-eluting stent or an everolimus-eluting stent. Patients are candidates if they present with at least 1 CTO lesion in a native coronary artery with a diameter of ≥2.50 mm to ≤4.00 mm and a length of <100 mm. In addition, 44 subjects will participate in an optical coherence tomography (OCT) substudy. Clinical follow-up is planned up to 5 years after stent implantation. Angiographic follow-up is planned at 12 months, whereas OCT will be obtained after the procedure, at 3 and 12 months. The primary end point is in-stent late lumen loss by quantitative coronary angiography at 12 months. The key secondary end point is neointimal thickness by OCT at 3 months. Imaging end points are assessed by an independent core lab. Clinical end points are adjudicated by an independent clinical events committee. Conclusion: The TARGET CTO trial compares a sirolimus target-eluting stent with an everolimus-eluting stent for management of CTOs according to contemporary interventional practices. The primary angiographic end points will be reported at 12 months and clinical follow-up will continue for up to 5 years.

EROSION III: A Multicenter RCT of OCT-Guided Reperfusion in STEMI With Early Infarct Artery Patency.

OBJECTIVES: The aim of this study was to test whether optical coherence tomographic (OCT) guidance would provide additional useful information beyond that obtained by angiography and lead to a shift in reperfusion strategy and improved clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) with early infarct artery patency. BACKGROUND: Angiography is limited in assessing the underlying pathophysiological mechanisms of the culprit lesion. METHODS: EROSION III (Optical Coherence Tomography-Guided Reperfusion in ST-Segment Elevation Myocardial Infarction With Early Infarct Artery Patency) is an open-label, prospective, multicenter, randomized, controlled study approved by the ethics committees of participating centers. Patients with STEMI who had angiographic diameter stenosis ≤ 70% and TIMI (Thrombolysis In Myocardial Infarction) flow grade 3 at presentation or after antegrade blood flow restoration were recruited and randomized to either OCT guidance or angiographic guidance. The primary efficacy endpoint was the rate of stent implantation. RESULTS: Among 246 randomized patients, 226 (91.9%) constituted the per protocol set (112 with OCT guidance and 114 with angiographic guidance). The median diameter stenosis was 54.0% (IQR: 48.0%-61.0%) in the OCT guidance group and 53.5% (IQR: 43.8%-64.0%) in the angiographic guidance group (P = 0.57) before randomization. Stent implantation was performed in 49 of 112 patients (43.8%) in the OCT group and 67 of 114 patients (58.8%) in the angiographic group (P = 0.024), demonstrating a 15% reduction in stent implantation with OCT guidance. In patients treated with stent implantation, OCT guidance was associated with a favorable result with lower residual angiographic diameter stenosis (8.7% ± 3.7% vs 11.8% ± 4.6% in the angiographic guidance group; P < 0.001). Two patients (1 cardiac death, 1 stable angina) met the primary safety endpoint in the OCT guidance group, as did 3 patients (3 cardiac deaths) in the angiographic guidance group (1.8% vs 2.6%; P = 0.67). Reinfarction was not observed in either group. At 1 year, the rates of predefined cardiocerebrovascular events were comparable between the groups (11.6% after OCT guidance vs 9.6% after angiographic guidance; P = 0.66). CONCLUSIONS: In patients with STEMI with early infarct artery patency, OCT guidance compared with angiographic guidance of reperfusion was associated with less stent implantation during primary percutaneous coronary intervention. These favorable results indicate the value of OCT imaging in optimizing the reperfusion strategy of patients with STEMI. (EROSION III: OCT- vs Angio-Based Reperfusion Strategy for STEMI; NCT03571269).

Fat-specific protein 27 undergoes ubiquitin-dependent degradation regulated by triacylglycerol synthesis and lipid droplet formation.

The fat-specific protein 27 (Fsp27), a protein localized to lipid droplets (LDs), plays an important role in controlling lipid storage and mitochondrial activity in adipocytes. Fsp27-null mice display increased energy expenditure and are resistant to high fat diet-induced obesity and diabetes. However, little is known about how the Fsp27 protein is regulated. Here, we show that Fsp27 stability is controlled by the ubiquitin-dependent proteasomal degradation pathway in adipocytes. The ubiquitination of Fsp27 is regulated by three lysine residues located in the C-terminal region. Substitution of these lysine residues with alanines greatly increased Fsp27 stability and enhanced lipid storage in adipocytes. Furthermore, Fsp27 was stabilized and rapidly accumulated following treatment with beta-agonists that induce lipolysis and fatty acid re-esterification in adipocytes. More importantly, Fsp27 stabilization was dependent on triacylglycerol synthesis and LD formation, because knockdown of diacylglycerol acyltransferase in adipocytes significantly reduced Fsp27 accumulation in adipocytes. Finally, we observed that increased Fsp27 during beta-agonist treatment preferentially associated with LDs. Taken together, our data revealed that Fsp27 can be stabilized by free fatty acid availability, triacylglycerol synthesis, and LD formation. The stabilization of Fsp27 when free fatty acids are abundant further enhances lipid storage, providing positive feedback to regulate lipid storage in adipocytes.

1-MNA Ameliorates High Fat Diet-Induced Heart Injury by Upregulating Nrf2 Expression and Inhibiting NF-κB in vivo and in vitro.

High levels of free fatty acids (FFA) are closely associated with obesity and the development of cardiovascular diseases. Recently, nicotinamide adenine dinucleotide (NAD) metabolism has emerged as a potential target for several modern diseases including diabetes. Herein, we explored the underlying mechanisms of NAD metabolism associated with the risk of cardiovascular disease. Our study found that nicotinamide N-methyltransferase (NNMT) mRNA levels were significantly increased in the hearts of FFA-bound-albumin-overloaded mice and in H9C2 cells treated with palmitic acid (PA). We studied the mechanisms underlining the anti-inflammatory and anti-oxidant activities of 1-methylnicotinamide (1-MNA), a metabolite of NNMT. We found a significantly higher level of reactive oxygen species, inflammation, apoptosis, and cell hypertrophy in PA-treated H9C2 cells and this effect was inhibited by 1-MNA treatment. in vivo, 1-MNA improved inflammation, apoptosis, and fibrosis damage in mice and this inhibition was associated with inhibited NF-κB activity. In conclusion, our study revealed that 1-MNA may prevent high fatty diet and PA-induced heart injury by regulating Nrf2 and NF-κB pathways.

CIDE proteins and metabolic disorders.

PURPOSE OF REVIEW: The cell death-inducing DFF45-like effector (CIDE) family proteins, comprising three members, Cidea, Cideb, and Fsp27 (Cidec), have emerged as important regulators for various aspects of metabolism. This review summarizes our current understanding about the physiological roles of CIDE proteins, their transcriptional regulations, and their underlying mechanism in controlling the development of metabolic disorders. RECENT FINDINGS: Animals with deficiency in Cidea, Cideb, and Fsp27 all display lean phenotypes with higher energy expenditure and are resistant to diet-induced obesity and insulin resistance. CIDE proteins, localized to lipid droplets and endoplasmic reticulum, control lipid metabolism in adipocytes and hepatocytes through regulating AMP-activated protein kinase stability and influencing lipogenesis or lipid droplet formation. The expression of CIDE proteins is controlled at both transcriptional and posttranslational levels and positively correlates with the development of obesity, liver steatosis, and insulin sensitivity in both rodents and humans. SUMMARY: CIDE proteins are important regulators of energy homeostasis and are closely linked to the development of metabolic disorders including obesity, diabetes, and liver steatosis. They may serve as potential molecular targets for the screening of therapeutic drugs for these diseases.

Integrin activation by talin, kindlin and mechanical forces.

Integrins are the major family of adhesion molecules that mediate cell adhesion to the extracellular matrix. They are essential for embryonic development and influence numerous diseases, including inflammation, cancer cell invasion and metastasis. In this Perspective, we discuss the current understanding of how talin, kindlin and mechanical forces regulate integrin affinity and avidity, and how integrin inactivators function in this framework.

The Kank family proteins in adhesion dynamics.

Integrin-mediated cell adhesion plays key roles for cell movement during development and tissue homeostasis. The dynamic life cycle of various integrin adhesions structures is required for the cell movements and regulated by the coordinated actions of both actomyosin and the microtubule (MT) cytoskeleton. The evolutionarily conserved Kank family proteins have emerged as regulators of adhesion dynamics by coordinating integrin-mediated force transmission with the recruitment of microtubules to integrins. These novel functions may play important roles in vivo and in human diseases.