IL-1ß mediates Candida tropicalis-induced immunosuppressive function of MDSCs to foster colorectal cancer.

BACKGROUND: There is increasing evidence that gut fungi dysbiosis plays a crucial role in the development and progression of colorectal cancer (CRC). It has been reported that gut fungi exacerbate the severity of CRC by regulating tumor immunity. Our previous studies have shown that the opportunistic pathogenic fungal pathogen, Candida tropicalis (C. tropicalis) promotes CRC progression by enhancing the immunosuppressive function of MDSCs and activating the NLRP3 inflammasome of MDSCs. However, the relationship between IL-1ß produced by NLRP3 inflammasome activation and the immunosuppressive function of MDSCs enhanced by C. tropicalis in CRC remains unclear. METHODS: The TCGA database was used to analyze the relationship between IL-1ß and genes related to immunosuppressive function of MDSCs in human CRC. The expression of IL-1ß in human CRC tissues was detected by immunofluorescence staining. The proteomic analysis was performed on the culture supernatant of C. tropicalis-stimulated MDSCs. The experiments of supplementing and blocking IL-1ß as well as inhibiting the NLRP3 inflammasome activation were conducted. A mouse colon cancer xenograft model was established by using MC38 colon cancer cell line. RESULTS: Analysis of CRC clinical samples showed that the high expression of IL-1ß was closely related to the immunosuppressive function of tumor-infiltrated MDSCs. The results of in vitro experiments revealed that IL-1ß was the most secreted cytokine of MDSCs stimulated by C. tropicalis. In vitro supplementation of IL-1ß further enhanced the immunosuppressive function of C. tropicalis-stimulated MDSCs and NLRP3-IL-1ß axis mediated the immunosuppressive function of MDSCs enhanced by C. tropicalis. Finally, blockade of IL-1ß secreted by MDSCs augmented antitumor immunity and mitigated C. tropicalis-associated colon cancer. CONCLUSIONS: C. tropicalis promotes excessive secretion of IL-1ß from MDSCs via the NLRP3 inflammasome. IL-1ß further enhances the immunosuppressive function of MDSCs to inhibit antitumor immunity, thus promoting the progression of CRC. Therefore, targeting IL-1ß secreted by MDSCs may be a potential immunotherapeutic strategy for the treatment of CRC.

A real-world disproportionality analysis of semaglutide: Post-marketing pharmacovigilance data.

AIM/INTRODUCTION: The recent adverse reactions associated with semaglutide have led the Food and Drug Administration (FDA) to issue a "black box warning", and it is necessary to analyze all reports of adverse reactions to improve the safety of its clinical use. MATERIALS AND METHODS: Statistical analyses and signal mining were performed by obtaining the adverse event reports related to semaglutide in the FAERS database from the first quarter of 2018 to the fourth quarter of 2023. We used disproportionality and Bayesian analysis to examine clinical and demographic attributes, trends reported quarterly, and contrasts between two distinct indications (obesity and type 2 diabetes). RESULTS: We found 10 unexpected adverse signals related to "pancreatic cancer", "intestinal obstruction", "cholecystitis", and "polycystic ovary" and both the two different indications had the same serious adverse reaction events occurring. CONCLUSIONS: This study identified many unexpected signals of serious adverse reactions, suggesting the importance of continuous post-marketing surveillance of semaglutide to understand its potential risks.

MSCs promote the efferocytosis of large peritoneal macrophages to eliminate ferroptotic monocytes/macrophages in the injured endometria.

BACKGROUND: Endometria are one of the important components of the uterus, which is located in the peritoneal cavity. Endometrial injury usually leads to intrauterine adhesions (IUA), accompanied by inflammation and cell death. We previously reported that both the endometrial ferroptosis was increased and monocytes/macrophages were involved in endometrial injury of IUA. Large peritoneal macrophages (LPMs) are recently reported to migrate into the injured tissues and phagocytose dead cells to repair the tissues. We previously demonstrated that mesenchymal stromal cells (MSCs) had made excellent progress in the repair of endometrial injury. However, it is unclear whether MSCs regulate the LPM efferocytosis against ferroptotic monocytes/macrophages in the injured endometria. METHODS: Here, endometrial injury in IUA mouse model was conducted by uterine curettage and LPS injection surgery and the samples were collected at different times to detect the changes of LPMs and ferroptotic monocytes/macrophages. We conducted LPMs depletion assay in vivo and LPMs and Erastin-induced ferroptotic THP-1 cells coculture systems in vitro to detect the LPM efferocytosis against ferroptotic monocytes/macrophages. The IUA model was treated with MSCs, and their effects on LPMs and endometrial repair were analyzed. Flow cytometry, western blotting, quantitative real-time PCR, immunohistochemical analysis, ELISA, and RNA-sequencing were performed. RESULTS: We found that LPMs migrated to the injured uteri in response to the damage in early phase (3 h), and sustained to a later stage (7 days). Astonishingly, we found that ferroptotic monocytes/macrophages were significantly increased in the injured uteri since 12 h after injury. Moreover, LPMs cocultured with Erastin-induced ferroptotic THP-1 cells in vitro, efferocytosis of LPMs against ferroptotic monocytes/macrophages was emerged. The mRNA expression profiles revealed that LPM efferocytosis against ferroptotic monocytes/macrophages was an induction of glycolysis program and depended on the PPARγ-HK2 pathway. Importantly, we validated that MSCs promoted the efferocytic capability and migration of LPMs to the injured uteri via secreting stanniocalcin-1 (STC-1). CONCLUSION: The data collectively demonstrated first the roles of LPMs via removal of ferroptotic monocytes/macrophages and provided a novel mechanism of MSCs in repairing the endometrial injury.

Mitochondria-mediated ferroptosis induced by CARD9 ablation prevents MDSCs-dependent antifungal immunity.

BACKGROUND: Caspase Recruitment Domain-containing protein 9 (CARD9) expressed in myeloid cells has been demonstrated to play an antifungal immunity role in protecting against disseminated candidiasis. Hereditary CARD9 ablation leads to fatal disseminated candidiasis. However, the myeloid cell types and molecular mechanisms implicated in CARD9 protecting against disseminated candidiasis remain wholly elusive. METHODS: The role of CARD9 ablation in exacerbating disseminated candidiasis was determined in vivo and in vitro. The molecular mechanism by which CARD9 ablation promotes acute kidney injury in disseminated candidiasis was identified by RNA-sequencing analysis. The expression of mitochondrial proteins and ferroptosis-associated proteins were measured by Quantitative real-time PCR and western blot. RESULTS: CARD9 ablation resulted in a reduced proportion of myeloid-derived suppressor cells (MDSCs) and a substantially lower expression of solute carrier family 7 member 11 (SLC7A11) in the kidneys, which increased susceptibility to acute kidney injury and renal ferroptosis during disseminated Candida tropicalis (C. tropicalis) infection. Moreover, CARD9-deficient MDSCs were susceptible to ferroptosis upon stimulation with C. tropicalis, which was attributed to augmented mitochondrial oxidative phosphorylation (OXPHOS) caused by reduced SLC7A11 expression. Mechanistically, C-type lectin receptors (CLRs)-mediated recognition of C. tropicalis promoted the expression of SLC7A11 which was transcriptionally manipulated by the Syk-PKCδ-CARD9-FosB signaling axis in MDSCs. FosB enhanced SLC7A11 transcription by binding to the promoter of SLC7A11 in MDSCs stimulated with C. tropicalis. Mitochondrial OXPHOS, which was negatively regulated by SLC7A11, was responsible for inducing ferroptosis of MDSCs upon C. tropicalis stimulation. Finally, pharmacological inhibition of mitochondrial OXPHOS or ferroptosis significantly increased the number of MDSCs in the kidneys to augment host antifungal immunity, thereby attenuating ferroptosis and acute kidney injury exacerbated by CARD9 ablation during disseminated candidiasis. CONCLUSIONS: Collectively, our findings show that CARD9 ablation enhances mitochondria-mediated ferroptosis in MDSCs, which negatively regulates antifungal immunity. We also identify mitochondria-mediated ferroptosis in MDSCs as a new molecular mechanism of CARD9 ablation-exacerbated acute kidney injury during disseminated candidiasis, thus targeting mitochondria-mediated ferroptosis is a novel therapeutic strategy for acute kidney injury in disseminated candidiasis.

Localization and Risk Stratification of Thyroid Nodules in Ultrasound Images Through Deep Learning.

OBJECTIVE: Deep learning algorithms have commonly been used for the differential diagnosis between benign and malignant thyroid nodules. The aim of the study described here was to develop an integrated system that combines a deep learning model and a clinical standard Thyroid Imaging Reporting and Data System (TI-RADS) for the simultaneous segmentation and risk stratification of thyroid nodules. METHODS: Three hundred four ultrasound images from two independent sites with TI-RADS 4 thyroid nodules were collected. The edge connection and Criminisi algorithm were used to remove manually induced markers in ultrasound images. An integrated system based on TI-RADS and a mask region-based convolution neural network (Mask R-CNN) was proposed to stratify subclasses of TI-RADS 4 thyroid nodules and to segment thyroid nodules in the ultrasound images. Accuracy and the precision-recall curve were used to evaluate stratification performance, and the Dice similarity coefficient (DSC) between the segmentation of Mask R-CNN and the radiologist's contour was used to evaluate the segmentation performance of the model. RESULTS: The combined approach could significantly enhance the performance of the proposed integrated system. Overall stratification accuracy of TI-RADS 4 thyroid nodules, mean average precision and mean DSC of the proposed model in the independent test set was 90.79%, 0.8579 and 0.83, respectively. Specifically, stratification accuracy values for TI-RADS 4a, 4b and 4c thyroid nodules were 95.83%, 84.21% and 77.78%, respectively. CONCLUSION: An integrated system combining TI-RADS and a deep learning model was developed. The system can provide clinicians with not only diagnostic assistance from TI-RADS but also accurate segmentation of thyroid nodules, which improves the applicability of the system in clinical practice.

Effect of Menopause Status on Brain Perfusion Hemodynamics.

BACKGROUND: The menopause transition is associated with an increasing risk of cerebrovascular disorders. However, the direct effect of menopause status on brain perfusion hemodynamics remains unclear. This study aimed to explore the influence of menopause status on cerebral blood flow (CBF) using arterial spin labeling magnetic resonance imaging. METHODS: In this cross-sectional study, 185 subjects underwent arterial spin labeling magnetic resonance imaging at a hospital in China between September 2020 and December 2022, including 38 premenopausal women (mean age, 47.74±2.02 years), 42 perimenopausal women (mean age, 50.62±3.15 years), 42 postmenopausal women (mean age, 54.02±4.09 years), and 63 men (mean age, 52.70±4.33 years) of a similar age range. Mean CBF values in the whole brain, gray matter, white matter, cortical gray matter, subcortical gray matter, juxtacortical white matter, deep white matter, and periventricular white matter were extracted. ANCOVA was used to compare mean CBF among the 4 groups, controlling for confounding factors. Student t test was applied to compare mean CBF between the 3 female groups and age-matched males, respectively. Multivariable regression analysis was used to analysis the effect of age, sex, and menopause status on the CBF of the whole brain, gray matter, white matter, and subregions. RESULTS: Perimenopausal and postmenopausal women showed a higher proportion of white matter hyperintensities compared with the other 2 groups (P<0.001). Premenopausal women exhibited higher CBF in the whole brain, gray matter, white matter, and subregions, compared with perimenopausal, postmenopausal women and men (P≤0.001). Multivariable regression analysis demonstrated significant effect of age and insignificant effect of sex on CBF for all participants. In addition, menopause status and the interaction between age and menopause status on CBF of whole brain, gray matter, white matter, and the subregions were observed in female participants, except for the deep and periventricular white matter regions, with premenopausal women exhibited a slight increase in CBF with age, while perimenopausal and postmenopausal women exhibited declines in CBF with age. CONCLUSIONS: The current findings suggest that alterations of brain perfusion hemodynamics begin during the perimenopause period, which may be due to the increased burden of white matter hyperintensities.

Efficacy of the long-acting gonadotropin-releasing hormone agonist long protocol on IVF/ICSI outcomes of patients with repeated implantation failure.

OBJECTIVE: The present study aimed to investigate the effect of long-acting gonadotropin-releasing hormone agonist (GnRHa) long protocol on in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes of patients with repeated implantation failure (RIF). METHODS: The present study was carried out from June 1, 2016 to June 30, 2021. A total of 665 patients with RIF were enrolled into the study and classified by the ovarian stimulation protocols. The outcome parameters were compared in each group. In addition, we evaluated the expression of homeobox A10 (HOXA10), integrin ß3 and leukemia inhibitory factor (LIF) in endometrial tissues between groups by quantitative RT-PCR. RESULTS: Patients who received the long-acting GnRHa long protocol had significantly higher clinical pregnancy rates (58.0%, 41.7% and 39.9%, respectively; P = 0.008 and 0.003), implantation rates (38.1%, 30.3%, and 30.1%, respectively; P = 0.001 and <0.001) and live birth rates (50.3%, 36.3%, and 31.3%, respectively; P = 0.020 and 0.002) compared with the short-acting GnRHa long protocol and GnRH antagonist protocol. In addition, we found that long-acting GnRHa could improve the expression of HOXA10 (P < 0.05). CONCLUSION: The long-acting GnRHa long protocol could improve endometrial receptivity and IVF/ICSI clinical outcomes of RIF patients compared with the short-acting GnRHa long protocol and GnRH antagonist protocol.

Mettl13 protects against cardiac contractile dysfunction by negatively regulating C-Cbl-mediated ubiquitination of SERCA2a in ischemic heart failure.

Ischemic heart failure (HF) remains a leading cause of morbidity and mortality. Maintaining homeostasis of cardiac function and preventing cardiac remodeling deterioration are critical to halting HF progression. Methyltransferase-like protein 13 (Mettl13) has been shown to regulate protein translation efficiency by acting as a protein lysine methyltransferase, but its role in cardiac pathology remains unexplored. This study aims to characterize the roles and mechanisms of Mettl13 in cardiac contractile function and HF. We found that Mettl13 was downregulated in the failing hearts of mice post-myocardial infarction (MI) and in a cellular model of oxidative stress. Cardiomyocyte-specific overexpression of Mettl13 mediated by AAV9-Mettl13 attenuated cardiac contractile dysfunction and fibrosis in response to MI, while silencing of Mettl13 impaired cardiac function in normal mice. Moreover, Mettl13 overexpression abrogated the reduction in cell shortening, Ca2+ transient amplitude and SERCA2a protein levels in the cardiomyocytes of adult mice with MI. Conversely, knockdown of Mettl13 impaired the contractility of cardiomyocytes, and decreased Ca2+ transient amplitude and SERCA2a protein expression in vivo and in vitro. Mechanistically, Mettl13 impaired the stability of c-Cbl by inducing lysine methylation of c-Cbl, which in turn inhibited ubiquitination-dependent degradation of SERCA2a. Furthermore, the inhibitory effects of knocking down Mettl13 on SERCA2a protein expression and Ca2+ transients were partially rescued by silencing c-Cbl in H2O2-treated cardiomyocytes. In conclusion, our study uncovers a novel mechanism that involves the Mettl13/c-Cbl/SERCA2a axis in regulating cardiac contractile function and remodeling, and identifies Mettl13 as a novel therapeutic target for ischemic HF.

Is the long-acting gonadotropin-releasing hormone agonist long protocol better for patients with endometriosis undergoing IVF?

OBJECTIVE: To investigate the effect of the long-acting gonadotropin-releasing hormone agonist (GnRHa) long protocol on in vitro fertilization (IVF) outcomes of patients with endometriosis (EMs). METHODS: This retrospective cohort study was carried out from July 1, 2016 to June 30, 2021. In all, 798 patients with EMs who underwent first IVF were enrolled. The patients were classified by the ovarian stimulation protocols. The clinical outcomes of IVF were compared in each group. RESULTS: Those EMs patients who received the long-acting GnRHa long protocol had significantly higher clinical pregnancy rate (72.00%, 60.70% and 50.90%, respectively; P = 0.047 and 0.010) and implantation rate (51.0%, 44.6%, and 38.7%, respectively; P = 0.006 and <0.001) compared with the short-acting GnRHa long protocol and the GnRH antagonist protocol. Live birth rate was also significantly higher than the GnRH antagonist protocol (60.10% vs. 40.0%, P = 0.032), but not statistically different from the short-acting GnRHa (60.10% vs. 53.80%, P = 0.443). In addition, they also had significantly higher duration of stimulation, total dose of gonadotropin, and number of high-quality embryos transferred compared with other groups (P < 0.001). CONCLUSIONS: The long-acting GnRHa long protocol could improve IVF outcomes of patients with EMs compared with the short-acting GnRHa long protocol and the GnRH antagonist protocol.

miR-101-3p contributes to the progression of preeclampsia by suppressing WDR5-mediated proliferation and invasion of trophoblast.

BACKGROUND: Decreased proliferation and invasion of trophoblast were proven to be involved in the pathogenesis of preeclampsia (PE). However, the regulatory network has not been clarified yet. This study aimed to explore the role of miR-101-3p in the progression of PE. METHODS: miR-101-3p expression in placentas of pregnant women with or without PE was analyzed by real-time quantitative PCR (RT-qPCR). Trophoblastic HTR-8/SVneo and HPT-8 cell lines were cultured and underwent hypoxia/reoxygenation (H/R) treatment to mimic PE in vitro. Cell proliferation and invasion were analyzed in gain-of and loss-of-function assays. Finally, we undertook in vivo studies to explore effects of miR-101-3p in the PE model. RESULTS: Compared to placentas from patients without PE, miR-101-3p expressed significantly higher in placentas from PE patients, and its level was positively correlated with the severity of patients. In vitro studies found that overexpression of miR-101-3p significantly suppressed cell proliferation and invasion, while knockdown of miR-101-3p reversed the impacts of H/R treatment. Further research showed that the expression of WD repeat domain 5 (WDR5) was significantly lower in placentas from patients with PE, and its level was negatively associated with the severity of patients. In vitro and in vivo studies confirmed that miR-101-3p promoted PE progression through the regulation of WD WDR5 expression. CONCLUSION: Increased expression of miR-101-3p in placenta contributes to the development of PE by suppressing WDR5-mediated proliferation and invasion of trophoblast.

CircHelz activates NLRP3 inflammasome to promote myocardial injury by sponging miR-133a-3p in mouse ischemic heart.

Myocardial infarction (MI)-induced the activation of NLRP3 inflammasome has been well known to aggravate myocardial injury and cardiac dysfunction by causing inflammation and pyroptosis in the heart. Circular RNAs (circRNAs) have been demonstrated to play critical roles in cardiovascular diseases. However, the functions and mechanisms of circRNAs in modulating cardiac inflammatory response and cardiomyocyte pyroptosis remain largely unknown. We revealed that circHelz, a novel circRNA transcribed from the helicase with zinc finger (Helz) gene, was significantly upregulated in both the ischemic myocardium of MI mouse and neonatal mouse ventricular cardiomyocytes (NMVCs) exposed to hypoxia. Overexpression of circHelz caused cardiomyocyte injury in NMVCs by activating the NLRP3 inflammasome and inducing pyroptosis, while circHelz silencing reduced these effects induced by hypoxia. Furthermore, knockdown of circHelz remarkably attenuated NLRP3 expression, decreased myocardial infarct size, pyroptosis, inflammation, and increased cardiac function in vivo after MI. Overexpression of miR-133a-3p in cardiomyocytes greatly prevented pyroptosis in the presence of hypoxia or circHelz by targeting NLRP3 in NMVCs. Mechanistically, circHelz functioned as an endogenous sponge for miR-133a-3p via suppressing its activity. Overall, our results demonstrate that circHelz causes myocardial injury by triggering the NLRP3 inflammasome-mediated pro-inflammatory response and subsequent pyroptosis in cardiomyocytes by inhibiting miR-133a-3p function. Therefore, interfering with circHelz/miR-133a-3p/NLRP3 axis might be a promising therapeutic approach for ischemic cardiac diseases.

Mettl14 Attenuates Cardiac Ischemia/Reperfusion Injury by Regulating Wnt1/ß-Catenin Signaling Pathway.

N6-methyladenosine (m6A) methylation in RNA is a dynamic and reversible modification regulated by methyltransferases and demethylases, which has been reported to participate in many pathological processes of various diseases, including cardiac disorders. This study was designed to investigate an m6A writer Mettl14 on cardiac ischemia-reperfusion (I/R) injury and uncover the underlying mechanism. The m6A and Mettl14 protein levels were increased in I/R hearts and neonatal mouse cardiomyocytes upon oxidative stress. Mettl14 knockout (Mettl14+/-) mice showed pronounced increases in cardiac infarct size and LDH release and aggravation in cardiac dysfunction post-I/R. Conversely, adenovirus-mediated overexpression of Mettl14 markedly reduced infarct size and apoptosis and improved cardiac function during I/R injury. Silencing of Mettl14 alone significantly caused a decrease in cell viability and an increase in LDH release and further exacerbated these effects in the presence of H2O2, while overexpression of Mettl14 ameliorated cardiomyocyte injury in vitro. Mettl14 resulted in enhanced levels of Wnt1 m6A modification and Wnt1 protein but not its transcript level. Furthermore, Mettl14 overexpression blocked I/R-induced downregulation of Wnt1 and ß-catenin proteins, whereas Mettl14+/- hearts exhibited the opposite results. Knockdown of Wnt1 abrogated Mettl14-mediated upregulation of ß-catenin and protection against injury upon H2O2. Our study demonstrates that Mettl14 attenuates cardiac I/R injury by activating Wnt/ß-catenin in an m6A-dependent manner, providing a novel therapeutic target for ischemic heart disease.

Kanglexin, a new anthraquinone compound, attenuates lipid accumulation by activating the AMPK/SREBP-2/PCSK9/LDLR signalling pathway.

Hyperlipidaemia is one of the major risk factors for atherosclerosis, coronary heart disease, stroke and diabetes. In the present study, we synthesized a new anthraquinone compound, 1,8-dihydroxy-3-succinic acid monoethyl ester-6-methylanthraquinone, and named it Kanglexin (KLX). The aim of this study was to evaluate whether KLX has a lipid-lowering effect and to explore the potential molecular mechanism. In this study, Sprague-Dawley rats were fed a high fat diet (HFD) for 5 weeks to establish a hyperlipidaemia model; then, the rats were orally administered KLX (20, 40, and 80 mg kg-1·d-1) or atorvastatin calcium (AT, 10 mg kg-1·d-1) once a day for 2 weeks. KLX had prominent effects on reducing blood lipids, hepatic lipid accumulation, body weight and the ratio of liver weight/body weight. Furthermore, KLXdramatically reduced the total cholesterol (TC) and triglyceride (TG) levels and lipid accumulation in a HepG2 cell model of dyslipidaemia induced by 1 mmol/L oleic acid (OA). KLX may decrease lipid levels by phosphorylating adenosine monophosphate-activated protein kinase (AMPK) and the downstream sterol regulatory element binding protein 2 (SREBP-2)/proprotein convertase subtilisin/kexin type 9 (PCSK9)/low-density lipoprotein receptor (LDLR) signalling pathway in the HFD rats and OA-treated HepG2 cells. The effects of KLX on the AMPK/SREBP-2/PCSK9/LDLR signalling pathway were abolished when AMPK was inhibited by compound C (a specific AMPK inhibitor) in HepG2 cells. In summary, KLX has an efficient lipid-lowering effect mediated by activation of the AMPK/SREBP-2/PCSK9/LDLR signalling pathway. Our findings may provide new insight into and evidence for the discovery of a new lipid-lowering drug for the prevention and treatment of hyperlipidaemia, fatty liver, and cardiovascular disease in the clinic.

A Latent Profile Analysis of Anxiety among Junior High School Students in Less Developed Rural Regions of China.

The purpose of this study is to understand the potential types of anxiety among middle school students by analyzing the current situation of middle school students' anxiety and its influencing factor. This study used a multistage stratified cluster random sampling to investigate students in grades 9 to 12. Mplus 7.4 was used for latent profile analysis. A total of 900 junior high school students were investigated. The junior high school students were divided into three subgroups by latent profile analysis. A total of 223 junior high school students experienced severe anxiety, accounting for 24.78%. Multivariate logistic regression analysis revealed that males are more likely to develop moderate and severe anxiety. The development of severe anxiety (OR = 0.562, p < 0.05) is less likely for students in schools with adequate mental health support. Students who were confident with their academic performances were less likely to develop moderate anxiety (OR = 0.377, p < 0.05). Students with extreme academic pressure are more likely to develop moderate anxiety (OR = 6.523, p < 0.05) and severe anxiety (OR = 11.579, p < 0.05). It is recommended that mental health counseling be set up in schools and to provide professional counselors to prevent serious anxiety for students. This paper also demonstrates a need to reduce students' academic pressure.

Inhibition of Dectin-1 in mice ameliorates cardiac remodeling by suppressing NF-κB/NLRP3 signaling after myocardial infarction.

The myocardial inflammatory response is a consequence of myocardial infarction (MI), which may deteriorate cardiac remodeling and lead to dysfunction in the heart post-MI. Dectin-1 is a c-type lectin, which has been shown to regulate innate immune responses to pathogens. However, the role of Dectin-1 in the heart diseases remains largely unknown. In this study, we aimed to investigate the effects of Dectin-1 on cardiac remodeling post-MI. We found that cardiac Dectin-1 mRNA and protein expressions were significantly elevated in C57BL/6 mice after MI. In vitro, hypoxia induced cardiomyocyte injury in parallel with increased Dectin-1 protein expression. Knockdown of Dectin-1 remarkably attenuated cardiomyocyte death under hypoxia and lipopolysaccharide (LPS) stimulation. In vivo administration of adeno-associated virus serotype 9 mediated silencing of Dectin-1, which significantly decreased cardiac fibrosis, dilatation, and improved cardiac function in the mice post-MI. At the molecular level, downregulation of Dectin-1 dramatically suppressed up-regulation of nuclear factor-κB (NF-κB), nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3), and the inflammatory genes involved in fibrogenesis and cardiac remodeling after MI. Furthermore, treatment with BAY11-7082, an inhibitor of NF-κB, repressed the activation of NF-κB, and attenuated LPS induced elevation of NLRP3 and cell death in cardiomyocytes. Collectively, upregulation of Dectin-1 in cardiomyocytes post-MI contributes to cardiac remodeling and cardiac dysfunction at least partially by activating NF-κB and NLRP3. This study identified Dectin-1 as a promising therapeutic target for ischemic heart disease.

Electrostatic orientation of enzymes on surfaces for ligand screening probed by force spectroscopy.

In this letter, we show that electrostatic immobilization provides a simple but effective approach for the immobilization and orientation of carbonic anhydrase onto charged surfaces. The enzyme is oriented differently on oppositely charged surfaces, with the majority of active sites facing upward on a positively charged surface and downward on a negatively charged surface. An array of negatively charged microscale surface patterns within a positively charged background was prepared by microcontact printing and used as the substrate to immobilize the enzymes. This enabled the probing of the enzyme orientations on the two differently charged surface regions by force spectroscopy with the same atomic force microscopy (AFM) probe modified with a thiolated sulfonamide inhibitor. The unbinding forces between the inhibitor tip and the enzyme immobilized on the two differently charged surfaces were measured. Two control experiments, blocking of the enzyme active site with a competitive inhibitor and removal of the zinc ion from the enzyme catalytic center, were employed to distinguish between specific and nonspecific interactions and to further verify the differences in enzyme orientation. Autocorrelation analysis of the force histograms was carried out to evaluate the specific single enzyme-inhibitor interaction force.

Atomic force microscopy study of the structural effects induced by echinomycin binding to DNA.

Atomic force microscopy (AFM) has been used to examine the conformational effects of echinomycin, a DNA bis-intercalating antibiotic, on linear and circular DNA. Four different 398 bp DNA fragments were synthesized, comprising a combination of normal and/or modified bases including 2,6-diaminopurine and inosine (which are the corresponding analogues of adenine and guanosine in which the 2-amino group that is crucial for echinomycin binding has been added or removed, respectively). Analysis of AFM images provided contour lengths, which were used as a direct measure of bis-intercalation. About 66 echinomycin molecules are able to bind to each fragment, corresponding to a site size of six base-pairs. The presence of base-modified nucleotides affects DNA conformation, as determined by the helical rise per base-pair. At the same time, the values obtained for the dissociation constant correlate with the types of preferred binding site available among the different DNA fragments; echinomycin binds to TpD sites much more tightly than to CpG sites. The structural perturbations induced when echinomycin binds to closed circular duplex pBR322 DNA were also investigated and a method for quantification of the structural changes is presented. In the presence of increasing echinomycin concentration, the plasmid can be seen to proceed through a series of transitions in which its supercoiling decreases, relaxes, and then increases.

Systematic manipulation of surface chemical reaction on the nanoscale: a novel approach for constructing three-dimensional nanostructures.

Nanoscale patches, created by nanografting a maleimide-terminated thiol into a self-assembled monolayer, were elaborated by sequential chemical reactions. Each stage in the nanofabrication was followed by atomic force microscopy (AFM), providing a controlled approach to the fabrication of novel three-dimensional (3D) surface nanostructures.