Peptide Expression Research Articles

Melanocortin 1 receptor deficiency protects against pathological cardiac hypertrophy

Abstract Background The melanocortin system, including adrenocorticotropic hormone, melanocyte-stimulating hormones and five melanocortin receptors (MC-R), regulates important physiological functions such as pigmentation and energy homeostasis. It has been also recently implicated in the regulation of pathological cardiac remodeling but the role of different MC-R subtypes in the heart remain unknown. Purpose Based on the abundant cardiac expression of MC1-R, we hypothesized that it is functionally active in the heart and regulates pathological cardiac remodeling. Methods Rat H9c2 cells were used to study the effects of the selective MC1-R agonist LD211 on intracellular signaling cascades, gene expression and cellular growth response by using Western blotting, quantitative RT-PCR and 3H-leucine incorporation assay, respectively. Recessive yellow mice (Mc1re/e) were used as a model of global MC1-R deficiency. Inducible cardiomyocyte-specific MC1-R knockout mouse model (Mc1r-cKO) was engineered by intercrossing MC1-R floxed mice (Mc1rfl/fl) with tamoxifen-inducible Myh6-MerCreMer transgenic mice (Myh6-MCM). Mc1re/e and Mc1r-cKO mice were subjected to transverse aortic constriction (TAC, 8 wks) or subcutaneous infusion of angiotensin II (Ang II, 4 wks) to induce pathological cardiac hypertrophy. Cardiac structure and function were measured by echocardiography and by histological examination of H&E-stained heart sections. Results Treatment of H9c2 cells with LD211 increased MAP-kinase p-38 phosphorylation (+53 %, P=0.005 vs control), upregulated the expression of B-type natriuretic peptide (Nppb, +40 %, P=0.03 vs control) and increased 3H-leucine incorporation (+27 %, P=0.006 vs control). Mc1re/e mice showed reduction in ventricular weight (-29 mg, P=0.03) compared to WT mice after TAC operation, and reduced left ventricular (LV) expression of atrial natriuretic peptide (Nppa) and fibrosis-related genes (Ctgf and Mmp2). In terms of LV systolic performance, TAC-operated Mc1re/e mice showed tendency towards improved LV ejection fraction (EF, +6 %, P=0.06) compared to WT mice. To further investigate whether the phenotype of Mc1re/e mice is driven by deficient MC1-R signaling in cardiomyocytes, we characterized Mc1r-cKO mice, which recapitulated the phenotypic features of Mc1re/e mice. Specifically, TAC-operated Mc1r-cKO mice displayed reduced ventricular weight (-38 mg, P=0.007) and downregulation of LV expression of Nppa and fibrosis-related genes compared to Myh6-MCM mice. Likewise, in a model of Ang II-induced cardiac hypertrophy, Mc1r-cKO mice showed reduced ventricular weight (-10 mg, P=0.015) compared to Myh6-MCM mice, indicating that the protection against pathological cardiac hypertrophy was model-independent. Conclusion Our studies demonstrate that MC1-R activation promotes cardiomyocyte growth in vitro, while global and cardiomyocyte-specific MC1-R deficiency protects against pathological cardiac hypertrophy induced by TAC or Ang II infusion.

Inhibition of ADAM10-mediated CX3CL1 shedding promotes survival and cardiac function early after myocardial infarction

Abstract Background and Purpose The metalloprotease ADAM10 has been implicated in immune regulatory processes, is upregulated in response to specific heart pathologies e.g. ischemic heart failure, and elevated serum levels of the ADAM10 substrates CX3CL1 and CXCL16 have been reported following infarction. The causal role of ADAM10 in cardiovascular diseases, however, is not known yet. By using human tissue biopsies, a cardiomyocyte-specific ADAM10 knockout mouse model (ADAM10 KO), and pharmacological ADAM10 inhibition we here comprehensively characterize the role of ADAM10 in the heart and in cardiac disease. Methods and Results We show that ADAM10 protein levels are upregulated in patients with ischemic cardiomyopathy (2.5-fold) and ADAM10 mRNA expression correlates with expression of atrial (NPPA) and brain natriuretic peptide (NPPB) mRNA. Upon infarction, ADAM10 expression is specifically induced in cardiomyocytes, and cardiomyocyte-specific ADAM10 KO as well as pharmacological inhibition (GI254023X) for only three days significantly improves overall survival, reduces scar size, and preserves cardiac function. Mechanistically, flow cytometry and bulk RNA sequencing identify a ADAM10/CX3CL1 axis to control neutrophil bone marrow egress and heart tissue infiltration after infarction. Diminished neutrophil migration results in long-term reduction of IL-1β-driven inflammation. Using cell culture experiments with ADAM10/CX3CL1 knockdown cardiomyocytes, we show that ADAM10-mediated ectodomain shedding of CX3CL1 specifically regulates neutrophil but not macrophage chemotaxis revealing a novel conceptual insight into how acute infarction triggers chemotactic signaling via ectodomain shedding. Conclusion Pharmacological and genetic targeting of the membrane sheddase ADAM10 is highly efficient for improving post-infarction cardiac function and survival via abolished post-translational CX3CL1 processing, neutrophil infiltration and IL-1β-dependent inflammation. Thus, our data reveal a novel therapeutic concept, which may close a clinically relevant therapeutic gap early after myocardial infarction.

Spatial transcriptomic analysis identifies a border zone with localized expression of brain natriuretic peptide in the inferobasal region of the left ventricle in patients with mitral valve prolapse

Abstract Background/Introduction Mitral valve prolapse (MVP) is a common cause of mitral regurgitation (MR), adverse left ventricular (LV) remodeling and arrhythmias. MVP induces mechanical stretch to the inferobasal (IB) myocardium and papillary muscles. The underlying regional and molecular pathology of MVP-induced LV remodeling remains incompletely understood. Purpose The aim was to characterize the molecular effects of mechanical stretch by comparing the regional gene expression of the IB region of LV with the interventricular septum in patients with MVP. Methods Myocardial biopsies were obtained from the IB LV (i.e. between papillary muscles) and the interventricular septum during mitral valve repair surgery for MVP-induced primary MR. The degree of cardiac fibrosis was detected and quantified by histology. We used spatial transcriptomics (ST) that - in contrast to traditional analyses of tissue homogenates - allows regional expressional analysis. Results Automated clustering of ST results correlated with histological staining of fibrosis in the IB and septal regions (R=0.97, P<0.0001), demonstrating good automated identification of fibrotic regions. The extent of fibrosis was similar between the inferobasal region and the septal control in the respective patients with MVP as determined by histological analysis and ST. The localized fibrotic areas of the inferobasal region showed decreased expression of cardiac myocytegenes such as RYR2, TNNI3, TNNC1 or TPM1, and increased expression of fibrous and EndMT markers such as COL3A1, BGN, SM22 or FN1. In the IB region, we identified a transition zone between healthy myocardium and fibrous tissue. This transition zone showed increased expression of the NPPB gene encoding brain natriuretic peptide (BNP), whereas NPPB was not increased in the septal region of the same patients. The upregulation of NPPB (6.4-fold, P=0.004) in the inferobasal region compared to the septal control was confirmed by qPCR in biopsies from patients with MVP. The identified transition zones were characterized by increased expression of genes such as IGFBP2 and LTBP2, which have been described to be associated with adverse LV remodeling in heart failure. Interestingly, the serum NT-proBNP levels (mean 276.8 ± 121.6 pg/ml) of the patients correlated with NPPB levels from the inferobasal region (R=0.76, P=0.01, N=9), whereas no correlation was found with NPPB levels from the septal control regions (R=0.17, P=0.65) of the same patients. Conclusions ST analysis in MVP identifies a transition zone of the inferobasal region of LV which is exposed to high mechanical stretch. This transition zone - but not the inferobasal fibrotic area nor the LV septum - is characterized by a specific increase in NBBP expression that correlates with increased NT-ProBNP serum concentrations. These special sequencing results indicate that mechanical stretch induces highly localized myocardial pathologies with systemic consequences.

Peptidomic analysis of follicular fluid in patients with polycystic ovarian syndrome.

Objective: The aim of this study was to analyze and compare the differential expression of peptides within the follicular fluid of polycystic ovary syndrome (PCOS) patients versus normal women by using peptidomics techniques. The underlying mechanisms involved in PCOS pathogenesis will be explored, together with screening and identification of potential functional peptides via bioinformatics analysis. Materials and methods: A total of 12 patients who underwent in vitro fertilization and embryo transfer (IVF-ET) at the Reproductive Medicine Center of Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from 1 September 2022 to 1 November 2022 were included in this study. The follicular fluid of PCOS patients (n = 6) and normal women (n = 6) were collected. The presence and concentration differences of various peptides were detected by the LC-MS/MS method. GO and KEGG analysis were performed on the precursor proteins of the differentially-expressed peptides, and protein network interaction analysis was carried out to identify functionally-relevant peptides among the various peptides. Results: A variety of peptides within the follicular fluid of PCOS versus normal patients were detected by peptidomics techniques. Altogether, 843 upregulated peptides and 236 downregulated peptides were detected (absolute fold change ≥2 and p < 0.05). Of these, 718 (718 = 488 + 230) peptides were only detected in the PCOS group, while 205 (205 = 174 + 31) were only detected in the control group. Gene Ontology enrichment and pathway analysis were performed to characterize peptides through their precursor proteins. We identified 18 peptides from 7 precursor proteins associated with PCOS, and 4 peptide sequences were located in the functional domains of their corresponding precursor proteins. Conclusion: In this study, differences in the follicular development of PCOS versus normal patients were revealed from the polypeptidomics of follicular development, which thus provided new insights for future studies on the pathological mechanisms of PCOS development.

Abstract 13962: Exploring the Therapeutic Potential of SGLT2 Inhibitors and Oral Ketone Ester in HFpEF: A Comprehensive Exploration of Cardiac Function, Structure, and Metabolism in a Rat Model

Introduction: This study aimed to assess the potential efficacy of the SGLT2 inhibitor empagliflozin and oral ketone ester supplementation as treatments for heart failure with preserved ejection fraction (HFpEF), which is commonly associated with obesity and type 2 diabetes mellitus. Methods: Twenty-week-old obese ZSF-1 rats were initially fed a high-fat diet (HFD) to establish and maintain the phenotype. Subsequently, the rats were randomly assigned to different treatment groups. These groups consisted of a control group receiving only the high-fat diet (HFD), as well as groups receiving empagliflozin, ketone ester (DeltaG®, KE), or a combination of both in addition to the HFD. Cardiac magnetic resonance imaging (CMR) and hyperpolarized carbon-13 (13C) labeled pyruvate magnetic resonance spectroscopy imaging were used to evaluate cardiac function and metabolism. Histological and molecular markers of cardiac remodeling were assessed in the left ventricle. Results: Untreated HFpEF rats exhibited obesity, diabetes, cardiac hypertrophy, atrial enlargement, lung congestion, increased cardiomyocyte size and fibrosis, as well as elevated expression of atrial natriuretic peptide (ANP), col1a1 (fibrosis marker), and TIMP1. The treatment groups displayed decreased body weight, increased circulating ketone levels, and reduced blood glucose levels. All treatment regimens significantly mitigated ventricular hypertrophy, atrial enlargement, and lung congestion. Furthermore, they reduced cardiomyocyte size, ANP expression, fibrosis marker expression, and increased cardiac ATP levels. CMR revealed that the combination of empagliflozin and KE resulted in improvement in diastolic function. Hyperpolarized [1-13C] pyruvate imaging revealed a decrease in lactate/pyruvate ratio in empagliflozin-treated hearts, indicating improved oxidative metabolism. Conclusions: The findings of this study suggest that targeting cardiometabolic dysregulation holds promise as an effective approach for the treatment of HFpEF. While both empagliflozin or KE alone demonstrated improvements in cardiac energetics and remodeling, the combination of empagliflozin and KE yielded the most notable benefits in enhancing cardiac diastolic function.

Increasing expression of STING by ERα antagonizes LCN2 downregulation during chronic endometritis

Chronic endometritis has a high incidence in infertile women, which is caused by endometrial microbiome infection. In response to microbial infection, the role of defensins during chronic endometritis need explored. Besides, the expression of estrogen and its receptors vary in different menstrual cycles, but their roles in chronic endometritis are still unclear. In this study, we used the human endometrial tissues to examine the expression of antimicrobial peptides (AMPs) α-defensin hNP-1 and β-defensins hBD-1, hBD-2, hBD-3, hBD-4 and LCN2. We found the expression of hBD-1 and LCN2 were downregulated in endometritis tissues, while the expressions of hBD-2, hBD-3, hBD-4, hNP-1, and estrogen and ERα were upregulated in chronic endometritis tissues compared to normal tissues. The expression and phosphorylation of STING, which is a crucial mediator of mammalian innate immunity in response to pathogens, was regulated with the treatment of ERα inhibitor raloxifene (Rx). Furthermore, using with the estrogen receptor inhibitor Rx and STING inhibitor H-151 significantly decreases the LCN2 expression. Taken together, these results suggested ERα was upregulated to modulate STING expression inducing LCN2 antimicrobial peptide expression to modulate the mucosal immunity during chronic endometritis.

Abstract 15078: Atrial and Brain Natriuretic Peptides Expression and Release in Pulmonary Hypertension

Introduction: Precapillary pulmonary hypertension (PH) is characterized by progressive overload for the right ventricle and right heart failure (RHF). N-terminal Brain Natriuretic Peptides (NTproBNP) and Atrial Natriuretic Peptides (ANP) are secreted from cardiomyocytes upon stretch. NTproBNP is used as biomarker for RHF. Aim: To study the association between ANP and NTproBNP and pressure overload in blood, right heart tissue and induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) from PH-patients. Methods: We analyzed NTproBNP in 344 PH-patients, 9 controls, and in 9 PH-patients before and 6-months after pulmonary endarterectomy (PEA). We measured NPPA and NPPB gene expression on end-stage human right ventricular (RV) and right atrial (RA) samples from 8 PH-patients and 5 controls. In addition, we performed immunofluoresence staining for ANP and BNP on RA tissue (N=4) and RV tissue (N=10) in PH and controls (N=5). iPSC-CMs from 1 male and 1 female PH-patients were stretched for 24h at 1Hz and 10% on the Flexcell FX-6000 system, and NTproBNP release was measured on static and stretched iPSC-CMs. NTproBNP levels were measured through ECLIA. Results: NTproBNP serum levels were elevated in PH-patients versus controls (918 vs 25 pg/mL, Fig1A). Pressure unloading in CTEPH patients did not result in a decrease in NTproBNP (Fig1B). In RV tissue of PH-patients NPPA expression was upregulated, but NPPB was not (Fig1C). ANP and BNP content was higher in RA and RV tissue of PH-patients (Fig1D-E). Finally, ~5x higher NTproBNP was released from male vs female iPSC-CMs under static conditions and after mechanical stretch (Fig1F). Conclusions: ANP and BNP showed important differences at gene and protein levels in relation to pressure overload. To confirm current results, further analyses on atrial and ventricular iPSC-CMs will be performed, in addition to mid-range proANP measurements in patients’ blood and iPSC-CMs conditioned medium.

Effect of pregnancy on the expression of nutrient-sensors and satiety hormones in mice

Small intestinal satiation pathways involve nutrient-induced stimulation of chemoreceptors leading to release of satiety hormones from intestinal enteroendocrine cells (ECCs). Whether adaptations in these pathways contribute to increased maternal food intake during pregnancy is unknown.To determine the expression of intestinal nutrient-sensors and satiety hormone transcripts and proteins across pregnancy in mice.Female C57BL/6J mice (10–12 weeks old) were randomized to mating and then tissue collection at early- (6.5 d), mid- (12.5 d) or late-pregnancy (17.5 d), or to an unmated age matched control group. Relative transcript expression of intestinal fatty acid, peptide and amino acid and carbohydrate chemoreceptors, as well as gut hormones was determined across pregnancy. The density of G-protein coupled receptor 93 (GPR93), free fatty acid receptor (FFAR) 4, cholecystokinin (CCK) and glucagon-like peptide1 (GLP-1) immunopositive cells was then compared between non-pregnant and late-pregnant mice.Duodenal GPR93 expression was lower in late pregnant than non-pregnant mice (P < 0.05). Ileal FFAR1 expression was higher at mid- than at early- or late-pregnancy. Ileal FFAR2 expression was higher at mid-pregnancy than in early pregnancy. Although FFAR4 expression was consistently lower in late-pregnant than non-pregnant mice (P < 0.001), the density of FFAR4 immunopositive cells was higher in the jejunum of late-pregnant than non-pregnant mice.A subset of protein and fatty acid chemoreceptor transcripts undergo region-specific change during murine pregnancy, which could augment hormone release and contribute to increased food intake. Further investigations are needed to determine the functional relevance of these changes.

Underlying mechanism of atrial fibrillation–associated Nppa-I137T mutation and cardiac effect of potential drug therapy

BackgroundMore than a hundred genetic loci have been associated with atrial fibrillation (AF). But the exact mechanism remains unclear and the treatment needs to be improved. ObjectiveThis study aimed to investigate the mechanism and potential treatment of NPPA mutation–associated AF. MethodsNppa knock-in (KI, p.I137T) rats were generated, and cardiac function was evaluated. Blood pressure was recorded using a tail-cuff system. The expression levels were measured using real-time polymerase chain reaction, enzyme-linked immunosorbent assay or Western blot analysis, and RNA-sequence analysis. Programmed electrical stimulation, patch clamp, and multielectrode array were used to record the electrophysical characteristics. ResultsMutant rats displayed downregulated expression of atrial natriuretic peptide but elevated blood pressure and enlarged left atrial end-diastolic diameter. Further, gene topology analysis suggested that the majority of differently expressed genes in Nppa KI rats were related to inflammation, electrical remodeling, and structural remodeling. The expression levels of C-C chemokine ligand 5 and galectin-3 involved in remodeling were higher, while there were declined levels of Nav1.5, Cav1.2, and connexin 40. AF was more easily induced in KI rats. Electrical remodeling included abbreviated action potentials, effective refractory period, increased late sodium current, and reduced calcium current, giving rise to conduction abnormalities. These electrophysiological changes could be reversed by the late sodium current blocker ranolazine and the Nav1.8 blocker A-803467. ConclusionOur findings suggest that structural remodeling related to inflammation and fibrosis and electrical remodeling involved in late sodium current underly the major effects of the Nppa (p.I137T) variant to induce AF, which can be attenuated by the late sodium current blocker and Nav1.8 blocker.

Pathogenicity of microsclerotia from Metarhizium robertsii against Aedes aegypti larvae and antimicrobial peptides expression by mosquitoes during fungal-host interaction

Aedes aegypti is a vector of various disease-causing arboviruses. Chemical insecticide-based methods for mosquito control have increased resistance in different parts of the world. Thus, alternative control agents such as the entomopathogenic fungi are excellent candidates to control mosquitoes as part of an ecofriendly strategy. There is evidence of the potential of entomopathogenic fungal conidia and blastospores for biological control of eggs, larval and adult stages, as well as the pathogenicity of fungal microsclerotia against adults and eggs. However, there are no studies on the pathogenicity of microsclerotia against either aquatic insects or insects that develop part of their life cycle in the water, such as the A. aegypti larvae. In this study, we assayed the production of microsclerotia and their pathogenicity against A. aegypti larvae of two isolates of Metarhizium robertsii, i.e., CEP 423 isolated in La Plata, Argentina, and the model ARSEF 2575. Both isolates significantly reduced the survival of A. aegypti exposed to their microsclerotia. The fungus-larva interaction resulted in a delayed response in the host. This was evidenced by the expression of some humoral immune system genes such as defensins and cecropin on the 9th day post-infection, when the fungal infection was consolidated as a successful process that culminates in larvae mortality. In conclusion, M. robertsii microsclerotia are promising propagules to be applied as biological control agents against mosquitoes since they produce pathogenic conidia against A. aegypti larvae.

Carbohydrate nutrition associated with health of overwintering honey bees.

In temperate climates, honey bees rely on stored carbohydrates to sustain them throughout the winter. In nature, honey serves as the bees' source of carbohydrates, but when managed, beekeepers often harvest honey and replace it with cheaper, artificial feed. The effects of alternative carbohydrate sources on colony survival, strength, and individual bee metabolic health are poorly understood. We assessed the impacts of carbohydrate diets (honey, sucrose syrup, high-fructose corn syrup, and invert syrup) on colony winter survival, population size, and worker bee nutritional state (i.e., fat content and gene expression of overwintered bees and emerging callow bees). We observed a nonsignificant trend for greater survival and larger adult population size among colonies overwintered on honey compared to the artificial feeds, with colonies fed high-fructose corn syrup performing particularly poorly. These trends were mirrored in individual bee physiology, with bees from colonies fed honey having significantly larger fat bodies than those from colonies fed high-fructose corn syrup. For bees fed honey or sucrose, we also observed gene expression profiles consistent with a higher nutritional state, associated with physiologically younger individuals. That is, there was significantly higher expression of vitellogenin and insulin-like peptide 2 and lower expression of insulin-like peptide 1 and juvenile hormone acid methyltransferase in the brains of bees that consumed honey or sucrose syrup relative to those that consumed invert syrup or high-fructose corn syrup. These findings further our understanding of the physiological implications of carbohydrate nutrition in honey bees and have applied implications for colony management.

236 Disrupted keratinocyte differentiation and increased chemokine and antimicrobial peptide expression in palmoplantar keratoderma due to keratin 9 mutation

236 Disrupted keratinocyte differentiation and increased chemokine and antimicrobial peptide expression in palmoplantar keratoderma due to keratin 9 mutation

Small extracellular vesicles derived from umbilical cord mesenchymal stem cells repair blood-spinal cord barrier disruption after spinal cord injury through down-regulation of Endothelin-1 in rats

Spinal cord injury could cause irreversible neurological dysfunction by destroying the blood-spinal cord barrier (BSCB) and allowing blood cells like neutrophils and macrophages to infiltrate the spinal cord. Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) found in the human umbilical cord have emerged as a potential therapeutic alternative to cell-based treatments. This study aimed to investigate the mechanism underlying the alterations in the BSCB permeability by human umbilical cord MSC-derived sEVs (hUC-MSCs-sEVs) after SCI. First, we used hUC-MSCs-sEVs to treat SCI rat models, demonstrating their ability to inhibit BSCB permeability damage, improve neurological repair, and reduce SCI-induced upregulation of prepro-endothelin-1 (prepro-ET-1) mRNA and endothelin-1 (ET-1) peptide expression. Subsequently, we confirmed that hUC-MSCs-sEVs could alleviate cell junction destruction and downregulate MMP-2 and MMP-9 expression after SCI, contributing to BSCB repair through ET-1 inhibition. Finally, we established an in vitro model of BSCB using human brain microvascular endothelial cells and verified that hUC-MSCs-sEVs could increase the expression of junction proteins in endothelial cells after oxygen-glucose deprivation by ET-1 downregulation. This study indicates that hUC-MSCs-sEVs could help maintain BSCB’s structural integrity and promote functional recovery by suppressing ET-1 expression.

Transcription factor STAT enhanced antimicrobial activities in Bombyx mori

STAT, a transcription factor in the JAK/STAT signaling pathway, regulates immune response to pathogens. In the silkworm (Bombyx mori), STAT exists as two split-forms, STAT-S and STAT-L. However, the role of STAT in silkworm immunity remains unclear. Our purpose was to investigate the effect of STAT on the expression of antimicrobial peptide (AMP) genes and resistance against pathogens. The expression levels of STAT-S and STAT-L were significantly up-regulated after induction by pathogenic microorganisms. In BmE cells, lipopolysaccharide (LPS), peptidoglycan (PGN) and β-glucan stimulated STAT-S and STAT-L to transfer from the cytoplasm to the nucleus. We found that overexpression of STAT-S and STAT-L in cells could promote the expression of AMPs. We generated transgenic silkworm lines overexpressing STAT-L or STAT-S (OE-STAT-S; OE-STAT-L) or interfering with STAT (A4-dsSTAT). Overexpression of STAT-S and STAT-L upregulated the expression of AMP genes in the OE-STAT-S and OE-STAT-L, increased the survival rates of the OE-STAT-S silkworms and lowered the mortality of OE-STAT-L silkworms infected with S. aureus or Beauveria bassiana. By contrast, the death rate of A4-dsSTAT silkworms was higher after infection with these pathogenic microorganisms. These findings may provide insights into the role of STAT in the antimicrobial immune response of silkworms.

Multi-engineered Graphene Extended-Gate Field-Effect Transistor for Peroxynitrite Sensing in Alzheimer's Disease.

The expression of β-amyloid peptides (Aβ), a pathological indicator of Alzheimer's disease (AD), was reported to be inapparent in the early stage of AD. While peroxynitrite (ONOO-) is produced excessively and emerges earlier than Aβ plaques in the progression of AD, it is thus significant to sensitively detect ONOO- for early diagnosis of AD and its pathological research. Herein, we unveiled an integrated sensor for monitoring ONOO-, which consisted of a commercially available field-effect transistor (FET) and a high-performance multi-engineered graphene extended-gate (EG) electrode. In the configuration of the presented EG electrode, laser-induced graphene (LIG) intercalated with MnO2 nanoparticles (MnO2/LIG) can improve the electrical properties of LIG and the sensitivity of the sensor, and graphene oxide (GO)-MnO2/Hemin nanozyme with ONOO- isomerase activity can selectively trigger the isomerization of ONOO- to NO3-. With this synergistic effect, our EG-FET sensor can respond to the ONOO- with high sensitivity and selectivity. Moreover, taking advantage of our EG-FET sensor, we modularly assembled a portable sensing platform for wireless tracking ONOO- levels in the brain tissue of AD transgenic mice at earlier stages before massive Aβ plaques appeared, and we systematically explored the complex role of ONOO- in the occurrence and development of AD.

N-terminal pro atrial natriuretic peptide as a prognostic marker of cardiac resynchronization therapy recipients

BackgroundAlthough the dynamic changes of atrial natriuretic peptide (ANP) expressions in a failing heart are well-documented, the clinical implications of detailed measurements of each ANP molecular form processed from proANP remain unclear. MethodsPatients screening was conducted on patients who were eligible for cardiac resynchronization therapy (CRT) between 2014 and 2019 in our institution. Blood samples and echocardiographic parameters were collected on the day before and six months after implantation. Total ANP, proANP, and N-terminal fragment of proANP (NT-proANP) were examined as predictive biomarkers for cardiac death, left ventricular assist device implantation, and heart failure hospitalization following CRT implantation. ResultsA total of 86 subjects (mean age 70 years, 64 males) who underwent successful CRT implantation were enrolled. Plasma levels of total ANP, proANP, and NT-proANP were not normally distributed [25.8 pM (interquartile range: 11.1–53.1), 2.2 pM (1.0–5.4), and 4.1 nM (2.4–7.1), respectively]. Over a median follow-up of 2.7 years, 31 patients (2 deaths and 29 heart failure hospitalizations) reached the endpoints. Among the different ANP forms, only NT-proANP emerged as an independent predictor of the composite outcome (adjusted odds ratio of 2.542 in those with levels above vs. below the median, 95 % confidence interval 1.151–5.615, p = 0.021). NT-proANP levels were associated with left atrial volume and left diastolic functional parameters and decreased in response to echocardiographic improvements at six months post-implantation (16 ± 44 % decrease in responders vs 18 ± 60 % increase in non-responders, p = 0.005). ConclusionPre-implantation NT-proANP levels could serve as a predictive factor for clinical outcomes in recipients of CRT.

Enhanced glucose homeostasis via Clostridium symbiosum-mediated glucagon-like peptide 1 inhibition of hepatic gluconeogenesis in mid-intestinal bypass surgery.

The small intestine is known to play a crucial role in the development and remission of diabetes mellitus (DM). However, the exact mechanism by which mid-small intestinal bypass improves glucose metabolism in diabetic rats is not fully understood. To elucidate the mechanisms by which mid-small intestinal bypass improves glucose metabolism. Streptozotocin (STZ) was used to induce DM in Sprague-Dawley (SD) rats at a dose of 60 mg/kg. The rats were then randomly divided into two groups: The mid-small intestine bypass (MSIB) group and the sham group (underwent switch laparotomy). Following a 6-wk recovery period post-surgery, the rats underwent various assessments, including metabolic parameter testing, analysis of liver glycogen levels, measurement of key gluconeogenic enzyme activity, characterization of the gut microbiota composition, evaluation of hormone levels, determination of bile acid concentrations, and assessment of the expression of the intestinal receptors Takeda G protein-coupled receptor 5 and farnesoid X receptor. The MSIB group of rats demonstrated improved glucose metabolism and lipid metabolism, along with increased hepatic glycogen content. Furthermore, there was a decrease in the expression of the key gluconeogenic enzymes phosphoenolpyruvate carboxykinase 1 and glucose-6-phosphatase. Importantly, the MSIB group exhibited a substantial increase in the abundances of intestinal Lactobacillus, Clostridium symbiosum, Ruminococcus gnavus, and Bilophila. Moreover, higher levels of secondary bile acids, such as intestinal lithocholic acid, were observed in this group. Remarkably, the changes in the gut microbiota showed a significant correlation with the expression of key gluconeogenic enzymes and glucagon-like peptide 1 (GLP-1) at 6 wk postoperatively, highlighting their potential role in glucose regulation. These findings highlight the beneficial effects of mid-small intestine bypass on glucose metabolism and the associated modulation of the gut microbiota. The findings of this study demonstrate that the introduction of postoperative intestinal Clostridium symbiosum in the mid-small intestine contributes to the enhancement of glucose metabolism in nonobese diabetic rats. This improvement is attributed to the increased inhibition of hepatic gluconeogenesis mediated by GLP-1, resulting in a favorable modulation of glucose homeostasis.

Peptides designed from a bacteriophage capsid protein function as synthetic transcription repressors

The bacteriophage capsid protein, Psu (polarity suppression), inhibits the bacterial transcription terminator, Rho. In an effort to find nontraditional antibacterial agents, we previously designed peptides from the Psu C terminus that function as inhibitors of Rho. Here, we demonstrated that these peptides have positive surface-charge densities, and they downregulate many genes in Escherichia coli. We hypothesized that these peptides could bind to nucleic acids and repress gene expression. One of these peptides, peptide 33, represses invitro transcription from the T7A1 and Plac promoters efficiently by blocking the access of RNA polymerase to the promoter, a mode of transcription repression akin to many bacterial repressors. Invivo, expressions of the peptides reduce the total RNA level as well as transcription from Plac and Posm promoters significantly. However, they are less efficient in repressing transcription from the rRNA promoters with a very high turnover of RNA polymerase. The peptide 33 binds to both single and dsDNA as well as to RNA with dissociation constants ranging from 1 to 5μM exhibiting preferences for the single-stranded DNA and RNAs. These interactions are salt-resistant and not sequence-specific. Interactions with dsDNA are entropy-driven, while it is enthalpy-driven for the ssDNA. This mode of interaction with nucleic acids is similar to many nonspecific ssDNA-binding proteins. Expression of peptide 33 induces cell elongation and impaired cell division, possibly due to the dislodging of the DNA-binding proteins. Overall, we surmised that these synthetic transcription repressors would function like bacterial nucleoid-associated proteins.

Differential expression of antimicrobial peptides in human fungal keratitis.

To analyze a series of antimicrobial peptides (AMPs) in corneal tissue from individuals with fungal keratitis (FK) during the active phase of the fungus infection and after healing. Patients undergone lamellar keratoplasty for the treatment of severe FK or corneal scar had their corneal buttons sampled. Quantitative real-time polymerase chain reaction (PCR) was used to ascertain the gene expression of human beta-defensin (HBD)-1, -2, -3, -9, S100A7, 8, 9, and LL-37. All AMPs' messenger ribonucleic acid (mRNA) expression was considerably elevated in all samples (n=12). In contrast to controls, where HBD-2, -3, and S100A7 mRNAs were expressed at very low levels, it was discovered that HBD-1, -9, S100A8, S100A9, and LL-37 were constitutively expressed in all healed samples (n=4). HBD-1, -2 -3, S100A7, and LL-37 mRNAs were significantly increased in all active FK samples (n=8). The levels of HBD-9, S100A8, and S100A9 mRNAs were moderately upregulated in all active FK samples. Subgroup comparison showed that HBD-2 was significantly increased in Fusarium keratitis samples (n=5), and LL-37 mRNAs were significantly enhanced in Aspergillus keratitis samples (n=3). Whereas there was not significantly increased of HBD-1, -3, -9, S100A7, 8, 9 mRNA in Aspergillus keratitis samples compared with Fusarium keratitis samples. AMPs expression is increased in active FK, but not all AMPs are equally expressed. HBD-2 and LL-37 expression levels are the highest, showing some specificity of AMP expression related to FK. Human AMPs, particularly HBD-2 may play a significant role in Fusarium keratitis and LL-37 might be the key player in Aspergillus keratitis.

Adeno-Associated Viral Vector-Delivered Pannexin-1 Mimetic Peptide Alleviates Airway Inflammation in an Allergen-Sensitized Mouse Model.

Asthma is a chronic inflammatory disease around the world. Extracellular adenosine triphosphate works as a dangerous signal in responding to cellular stress, irritation, or inflammation. It has also been reported its association with the pathogenicity in asthma, with increased level in lungs of asthmatics. Pannexin-1 is one of the routes that contributes to the release of adenosine triphosphate form intracellular to extracellular. The aim of this study was to apply pannexin-1 peptide antagonist 10Panx1 into adeno-associated viral (AAV) vectors on ovalbumin (OVA)-induced asthmatic mouse model. The results demonstrated that this treatment was able to reduce the adenosine triphosphate level in bronchoalveolar lavage fluid and downregulate the major relevant to the symptom of asthma attack, airway hyperresponsiveness to methacholine. The histological data also gave a positive support with decreased tissue remodeling and mucus deposition. Other asthmatic related features, including eosinophilic inflammation and OVA-specific T helper type 2 responses, were also decreased by the treatment. Beyond the index of inflammation, the proportion of effector and regulatory T cells was examined to survey the potential mechanism behind. The data provided a slightly downregulated pattern in lung GATA3+ CD4 T cells. However, an upregulated population of CD25+FoxP3+ CD4 T cells was seen in spleens. These data suggested that exogeneous expression of 10Panx1 peptide was potential to alleviated asthmatic airway inflammation, and this therapeutic effect might be from 10Panx1-mediated disruption of T cell activation or differentiation. Collectively, AAV vector-mediated 10Panx1 expression could be a naval therapy option to develop.