Angiotensin II increases periostin expression via Ras/p38 MAPK/CREB and ERK1/2/TGF-β1 pathways in cardiac fibroblasts

Fetal programming and lactation: modulating gene expression in response to undernutrition during intrauterine life

BACKGROUND

Adverse environmental conditions during intrauterine life, known as fetal programming, significantly contribute to the development of diseases in adulthood. Fetal programming induced by factors like maternal undernutrition leads to low birth weight and increases the risk of cardiometabolic diseases.

METHODS

We studied a rat model of maternal undernutrition during gestation (MUN) to investigate gene expression changes in cardiac tissue using RNA-sequencing of day 0-1 litters. Moreover, we analyzed the impact of lactation at day 21, in MUN model and cross-fostering experiments, on cardiac structure and function assessed by transthoracic echocardiography, and gene expression changes though qPCR.

RESULTS

Our analysis identified specific genes with altered expression in MUN rats at birth. Two of them, Agt and Pparg, stand out for being associated with cardiac hypertrophy and fibrosis. At the end of the lactation period, MUN males showed increased expression of Agt and decreased expression of Pparg, correlating with cardiac hypertrophy. Cross-fostering experiments revealed that lactation with control breastmilk mitigated these expression changes reducing cardiac hypertrophy in MUN males.

CONCLUSIONS

Our findings highlight the interplay between fetal programming, gene expression, and cardiac hypertrophy suggesting that lactation period is a potential intervention window to mitigate the effects of fetal programming.

IMPACT

Heart remodeling involves the alteration of several groups of genes and lactation period plays a key role in establishing gene expression modification caused by fetal programming. We could identify expression changes of relevant genes in cardiac tissue induced by undernutrition during fetal life. We expose the contribution of the lactation period in modulating the expression of Agt and Pparg, relevant genes associated with cardiac hypertrophy. This evidence reveal lactation as a crucial intervention window for preventing or countering fetal programming.

Targeted Antisense Oligonucleotide-Mediated Skipping of Murine Postn Exon 17 Partially Addresses Fibrosis in D2.mdx Mice

Periostin, a multifunctional 90 kDa protein, plays a pivotal role in the pathogenesis of fibrosis across various tissues, including skeletal muscle. It operates within the transforming growth factor beta 1 (Tgf-β1) signalling pathway and is upregulated in fibrotic tissue. Alternative splicing of Periostin's C-terminal region leads to six protein-coding isoforms. This study aimed to elucidate the contribution of the isoforms containing the amino acids encoded by exon 17 (e17+ Periostin) to skeletal muscle fibrosis and investigate the therapeutic potential of manipulating exon 17 splicing. We identified distinct structural differences between e17+ Periostin isoforms, affecting their interaction with key fibrotic proteins, including Tgf-β1 and integrin alpha V. In vitro mouse fibroblast experimentation confirmed the TGF-β1-induced upregulation of e17+ Periostin mRNA, mitigated by an antisense approach that induces the skipping of exon 17 of the Postn gene. Subsequent in vivo studies in the D2.mdx mouse model of Duchenne muscular dystrophy (DMD) demonstrated that our antisense treatment effectively reduced e17+ Periostin mRNA expression, which coincided with reduced full-length Periostin protein expression and collagen accumulation. The grip strength of the treated mice was rescued to the wild-type level. These results suggest a pivotal role of e17+ Periostin isoforms in the fibrotic pathology of skeletal muscle and highlight the potential of targeted exon skipping strategies as a promising therapeutic approach for mitigating fibrosis-associated complications.

Association of RASGRP1 polymorphism with vascular complications in Chinese diabetic patients with glycemic control and antihypertensive treatment

BACKGROUND

Studies have shown that RASGRP1 was potently associated with the onset of type 2 diabetes mellitus (T2DM), and RASGRP1 rs7403531 was significantly correlated with islet function in T2DM patients. However, the effect of RASGRP1 polymorphism on blood glucose and blood pressure in T2DM patients after continuous treatment has yet to be fully elucidated.

OBJECTIVE

This study aimed to explore the association between RASGRP1 genetic polymorphism and cardiovascular complications in T2DM patients, so as to provide more evidence for the individualized treatment of T2DM patients.

METHODS

We retrospectively analyzed a large-scale multicenter drug clinical study cohort that based on a 2 × 2 factorial (glucose control axis and blood pressure lowering axis) randomized controlled design, with follow-up for 5 years. The major vascular endpoint events included cardiovascular death, non-fatal stroke, coronary heart disease, new-onset or worsening renal disease, and diabetic retinopathy. RASGRP1 rs12593201, rs56254815 and rs7403531 were finally selected as candidate single nucleotide polymorphisms. Mixed linear model and Cox hazard ratio (HR) model were used for data analysis with IBM SPSS (version 20.0 for windows; Chicago, IL).

RESULTS

Our study enrolled 1357 patients with high-risk diabetes, with a mean follow-up duration of 4.8 years. RASGRP1 rs7403531 was associated with vascular events in hypoglycemic and antihypertensive therapy. Specifically, compared with CC carriers, patients with CT/TT genotype had fewer major microvascular events (HR = 0.41, 95% confidence interval (CI) 0.21-0.80, P = 0.009), and reduced the risk of major eye disease events (HR = 0.44, 95% CI 0.20-0.94, P = 0.03). For glucose lowering axis, CT/TT carriers had a lower risk of secondary nephropathy (HR = 0.48, 95% CI 0.25-0.92, P = 0.03) in patients with standard glycemic control. For blood pressure lowering axis, all cerebrovascular events (HR = 2.24, 95% CI 1.11-4.51, P = 0.025) and stroke events (HR = 2.07, 95% CI 1.03-4.15, P = 0.04) were increased in patients with CC genotype compared to those with CT/TT genotype in the placebo group, respectively. Furthermore, patients with CC genotype showed a reduced risk of major cerebrovascular events in antihypertensive group (HR = 0.36, 95% CI 0.15-0.86, P = 0.021). For RASGRP1 rs56254815, compared with the AA genotype carriers, the systolic blood pressure of AG/GG carriers in the antihypertensive group decreased by 1.5mmhg on average (P = 0.04). In the placebo group, the blood pressure of AG/GG carriers was 1.7mmHg higher than that of AA carriers (P = 0.02).

CONCLUSION

We found that patients with G allele of RASGRP1 (rs56254815) showed a better antihypertensive therapy efficacy in T2DM patients. The rs7403531 T allele could reduce the risk of major microvascular events and major eye diseases in T2DM patients receiving either hypoglycemic or antihypertensive therapy. Our findings suggest that RASGRP1 genetic polymorphism might predict the cardiovascular complications in T2DM patients.

Current evidence regarding the cellular mechanisms associated with cancer progression due to cardiovascular diseases

Several large cohort studies in cardiovascular disease (CVD) patients have shown an increased incidence of cancer. Previous studies in a myocardial infarction (MI) mouse model reported increased colon, breast, and lung cancer growth. The potential mechanisms could be due to secreted cardiokines and micro-RNAs from pathological hearts and immune cell reprogramming. A study in a MI-induced heart failure (HF) mouse demonstrated an increase in cardiac expression of SerpinA3, resulting in an enhanced proliferation of colon cancer cells. In MI-induced HF mice with lung cancer, the attenuation of tumor sensitivity to ferroptosis via the secretion of miR-22-3p from cardiomyocytes was demonstrated. In MI mice with breast cancer, immune cell reprogramming toward the immunosuppressive state was shown. However, a study in mice with renal cancer reported no impact of MI on tumor growth. In addition to MI, cardiac hypertrophy was shown to promote the growth of breast and lung cancer. The cardiokine potentially involved, periostin, was increased in the cardiac tissue and serum of a cardiac hypertrophy model, and was reported to increase breast cancer cell proliferation. Since the concept that CVD could influence the initiation and progression of several types of cancer is quite new and challenging regarding future therapeutic and preventive strategies, further studies are needed to elucidate the potential underlying mechanisms which will enable more effective risk stratification and development of potential therapeutic interventions to prevent cancer in CVD patients.

Expression of the Pro-Fibrotic Marker Periostin in a Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is characterised by fibrotic tissue deposition in skeletal muscle. We assessed the role of periostin in fibrosis using mdx mice, an established DMD murine model, for which we conducted a thorough examination of periostin expression over a year. RNA and protein levels in diaphragm (DIA) muscles were assessed and complemented by a detailed histological analysis at 5 months of age. In dystrophic DIAs, periostin (Postn) mRNA expression significantly exceeded that seen in wildtype controls at all timepoints analysed, with the highest expression at 5 months of age (p < 0.05). We found Postn to be more consistently highly expressed at the earlier timepoints compared to established markers of fibrosis like transforming growth factor-beta 1 (Tgf-β1) and connective tissue growth factor (Ctgf). Immunohistochemistry confirmed a significantly higher periostin protein expression in 5-month-old mdx mice compared to age-matched healthy controls (p < 0.01), coinciding with a significant fibrotic area percentage (p < 0.0001). RT-qPCR also indicated an elevated expression of Tgf-β1, Col1α1 (collagen type 1 alpha 1) and Ctgf in mdx DIAs compared to wild type controls (p < 0.05) at 8- and 12-month timepoints. Accordingly, immunoblot quantification demonstrated elevated periostin (3, 5 and 8 months, p < 0.01) and Tgf-β1 (8 and 12 months, p < 0.001) proteins in the mdx muscle. These findings collectively suggest that periostin expression is a valuable marker of fibrosis in this relevant model of DMD. They also suggest periostin as a potential contributor to fibrosis development, with an early onset of expression, thereby offering the potential for timely therapeutic intervention and its use as a biomarker in muscular dystrophies.

Epigenetic signatures in cardiac fibrosis: Focusing on noncoding RNA regulators as the gatekeepers of cardiac fibroblast identity

Cardiac fibroblasts play a pivotal role in cardiac fibrosis by transformation of fibroblasts into myofibroblasts, which synthesis and secrete a large number of extracellular matrix proteins. Ultimately, this will lead to cardiac wall stiffness and impaired cardiac performance. The epigenetic regulation and fate reprogramming of cardiac fibroblasts has been advanced considerably in recent decades. Non coding RNAs (microRNAs, lncRNAs, circRNAs) regulate the functions and behaviors of cardiac fibroblasts, including proliferation, migration, phenotypic transformation, inflammation, pyroptosis, apoptosis, autophagy, which can provide the basis for novel targeted therapeutic treatments that abrogate activation and inflammation of cardiac fibroblasts, induce different death pathways in cardiac fibroblasts, or make it sensitive to established pathogenic cells targeted cytotoxic agents and biotherapy. This review summarizes our current knowledge in this field of ncRNAs function in epigenetic regulation and fate determination of cardiac fibroblasts as well as the details of signaling pathways contribute to cardiac fibrosis. Moreover, we will comment on the emerging landscape of lncRNAs and circRNAs function in regulating signal transduction pathways, gene translation processes and post-translational regulation of gene expression in cardiac fibroblast. In the end, the prospect of cardiac fibroblasts targeted therapy for cardiac fibrosis based on ncRNAs is discussed.

Liensinine improves AngII-induced vascular remodeling via MAPK/TGF-β1/Smad2/3 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Liensinine(Lien, C37H42N2O6) is an alkaloid compound from plumula nelumbinis that demonstrates an antihypertensive effect. The protective effects of Lien on target organs during hypertension are still unclear.

AIM OF THE STUDY

This study aimed to understand the mechanism of Lien during the treatment of hypertension, with emphasis on vascular protection.

MATERIALS AND METHODS

Lien was extracted and isolated from plumula nelumbinis for further study. In vivo model of Ang II-induced hypertension, non-invasive sphygmomanometer was used to detect the blood pressure in and out of the context of Lien intervention. Ultrasound was used to detect the abdominal aorta pulse wave and media thickness of hypertensive mice, and RNA sequencing was used to detect the differential genes and pathways of blood vessels. The intersection of Lien and MAPK protein molecules was detected by molecular interconnecting technique. The pathological conditions of abdominal aorta vessels of mice were observed by HE staining. The expression of PCNA, α-SMA, Collagen Type Ⅰ and Collagen Type Ⅲ proteins were detected by IHC. The collagen expression in the abdominal aorta was detected by Sirius red staining. The MAPK/TGF-β1/Smad2/3 signaling and the protein expression of PCNA and α-SMA was detected by Western blot. In vitro, MAPK/TGF-β1/Smad2/3 signaling and the protein expression of PCNA and α-SMA were detected by Western blot, and the expression of α-SMA was detected by immunofluorescence; ELISA was used to detect the effect of ERK/MAPK inhibitor PD98059 on Ang Ⅱ-induced TGF-β1secrete; and the detection TGF-β1and α-SMA protein expression by Western blot; Western blot was used to detect the effect of ERK/MAPK stimulant12-O-tetradecanoyl phorbol-13-acetate (TPA) on the protein expression of TGF-β1 and α-SMA.

RESULTS

Lien displayed an antihypertensive effect on Ang Ⅱ-induced hypertension, reducing the pulse wave conduction velocity of the abdominal aorta and the thickness of the abdominal aorta vessel wall, ultimately improving the pathological state of blood vessels. RNA sequencing further indicated that the differential pathways expressed in the abdominal aorta of hypertensive mice were enriched in proliferation-related markers compared with the Control group. The profile of differentially expressed pathways was ultimately reversed by Lien. Particularly, MAPK protein demonstrated good binding with the Lien molecule. In vivo, Lien inhibited Ang Ⅱ-induced abdominal aorta wall thickening, reduced collagen deposition in the ventral aortic vessel, and prevented the occurrence of vascular remodeling by inhibiting MAPK/TGF-β1/Smad2/3 signaling activation. In addition, Lien inhibited the activation of Ang II-induced MAPK and TGF-β1/Smad2/3 signaling, attenuating the expression of PCNA and inhibiting the reduction of α-SMA, collectively playing a role in the inhibition of Ang Ⅱ-induced hypertensive vascular remodeling. PD98059 alone could inhibit Ang Ⅱ-induced elevation of TGF-β1 and the decrease of α-SMA expression. Further, PD98059 combined with Lien had no discrepancy with the inhibitors alone. Simultaneously TPA alone could significantly increase the expression of TGF-β1 and decrease the expression of α-SMA. Further, Lien could inhibit the effect of TPA.

CONCLUSION

This study helped clarify the protective mechanism of Lien during hypertension, elucidating its role as an inhibitor of vascular remodeling and providing an experimental basis for the research and development of novel antihypertensive therapies.

Salvianolic acid A alleviates heart failure with preserved ejection fraction via regulating TLR/Myd88/TRAF/NF-κB and p38MAPK/CREB signaling pathways

Heart failure with preserved ejection fraction (HFpEF) is a morbid, fatal, and common syndrome for which lack of evidence-based therapies. Salvianolic acid A (SAA), a major active ingredient of Salvia miltiorrhiza Burge, has shown potential to protect against cardiovascular diseases. This study aims to elucidate whether SAA possessed therapeutic activity against HFpEF and explore the potential mechanism. HFpEF mouse model was established infusing a combination of high-fat diet (HFD) and Nω-nitro-L-arginine methyl ester (L-NAME) for 14 weeks. After 10 weeks of feeding, HFpEF mice were given SAA (2.5, 5, 10 mg/kg) via oral gavage for four weeks. Body weight, blood pressure, blood lipids, glucose tolerance, exercise performance, cardiac systolic/diastolic function, cardiac pathophysiological changes, and inflammatory factors were assessed. Experimental results showed that SAA reduced HFpEF risk factors, such as body weight gain, glucose intolerance, lipid disorders, and increased exercise tolerance in HFpEF mice. Moreover, SAA not only relieved myocardial hypertrophy and fibrosis by reducing interventricular septal wall thickness, left ventricular posterior wall thickness, left ventricular mass, heart index, cardiomyocyte cross-sectional area and cardiac collagen content, but also improved cardiac diastolic function via reducing E/E' ratio. Finally, SAA inhibited TLR2/TLR4-mediated Myd88 activation and its downstream molecules TRAF6 and IRAK4, which decreases the release of proinflammatory cytokines and mediators through NF-κB and p38 MAPK pathways. In conclusion, SAA could attenuate cardiac inflammation and cardiac disfunction by TLR/Myd88/TRAF/NF-κB and p38MAPK/CREB signaling pathways in HFpEF mice, which provides evidence for SAA as a potential drug for treatment of HFpEF in clinic.

IL-6 induces periostin production in human ACL remnants: a possible mechanism causing post-traumatic osteoarthritis

OBJECTIVE

Perostin (POSTN) and IL-6 consistently elevated after ACL injury, and ACL has been proposed as the major source of POSTN. However, there is a lack of evidence whether IL-6 induces ACL remnants to produce POSTN. This study aimed to investigate the effect of IL-6 on POSTN production in ACL fibroblasts, which may help us understand more about the mechanism of PTOA after ACL injury and ACL reconstruction.

METHODS

ACL remnants were harvested from 27 patients undergoing ACL reconstruction. Quantitative real-time polymerase chain reaction (PCR) was performed to examine the POSTN gene expression of ACL fibroblasts after treatment of different concentrations of IL-6. The POSTN protein production of ACL fibroblasts was determined using western blot analysis. The blockers of possible signaling pathways, including PI3K/Akt, Ras/MAPK, and JAK/STAT pathways, were added to test whether the effect of IL-6 on ACL fibroblast could be attenuated. ACL fibroblast and chondrocyte co-culture was carried out to determine the influence of ACL and IL-6 on chondrocytes.

RESULTS

Quantitative real-time PCR showed that IL-6 time-dependently and dose-dependently increased POSTN gene expression of ACL fibroblast. Western blot analysis also revealed that IL-6 dose-dependently induced POSTN protein production. Regarding the chronicity of ACL injury, the POSTN protein production was comparable between ACL remnants which were derived within 3 months of injury and at least 6 months after injury. PI3K/Akt blockers could attenuate the effect of IL-6 on ACL remnants, whereas Ras/MAPK and JAK/STAT did not decrease POSTN production. The coexistence of ACL and IL-6 induced more MMP-13 and ADAMTS-4 by chondrocytes.

CONCLUSIONS

IL-6 induced ACL remnants to produce POSTN. This effect could be attenuated by the PI3K/Akt blocker. Coexistence of IL-6 and ACL remnants may accelerate post-traumatic arthritis.

Primary cardiac fibroblast cell culture: methodological considerations for physiologically relevant conditions

Primary cardiac fibroblast (CF) tissue culture is a necessary tool for interrogating specific signaling mechanisms that dictate the phenotypic heterogeneity observed in vivo in different disease states. Traditional approaches that use tissue culture plastic and nutrient-rich medium have been shown to induce CF activation and, therefore, alter CF subpopulation composition. This shift away from in vivo phenotypes complicate the interpretation of results through the lens of the animal model. As the field works to identify CF diversity, these methodological flaws have begun to be addressed and more studies are focused on the dynamic interaction of CFs with their environment. This review focuses on the aspects of tissue culture that impact CF activation and, therefore, require consideration when designing in vitro experiments. The complexity of CF biology overlaid onto diverse model systems highlight the need for study-specific optimization and validation.

Quercetin Alleviates Asthma-Induced Airway Inflammation and Remodeling through Downregulating Periostin via Blocking TGF-β1/Smad Pathway

INTRODUCTION

The aim of the study was to discuss whether the anti-asthmatic effect of quercetin is related to periostin and the downstream molecular pathway of quercetin's anti-asthmatic effect.

METHODS

We constructed asthmatic mice, sensitized by ovalbumin, and administrated different treatments into mice according to the experimental design. In this study, we mainly observed the inflammatory response, airway fibrosis, and airway hyperresponsiveness in asthmatic mice. Pathological stains (H&E, PAS, and Masson) were performed. We also detected the inflammation factors and fibrosis-related cytokines by enzyme-linked immunosorbent serologic assay. In addition, we also explored the level of periostin by enzyme-linked immunosorbent serologic assay and Western blot. At the same time, TGF-β1/Smad pathway was also determined by Western blot.

RESULTS

A high expression of periostin was found in asthmatic mice, and quercetin decreases periostin content in bronchoalveolar lavage fluid. Quercetin and OC-20 inhibit airway inflammation response, airway fibrosis, and airway hyperreactivity. Quercetin downregulated TGF-β1/Smad pathway in the lung tissues of asthmatic mice. Anti-asthma role of quercetin is related to periostin. Then deeper mechanical study revealed that inhibiting TGF-β1 could improve asthmatic symptoms, and quercetin exerted the protective effect on asthmatic mice through inhibition of TGF-β1/Smad pathway.

CONCLUSION

Quercetin provided a protective role against asthma via periostin, manifested by mild inflammatory infiltration, reduced goblet cell proliferation, and reduced airway fibrosis. TGF-β1/Smad pathway is an important transduction system, participating in the protective effect of quercetin on asthma.

CTRP family in diseases associated with inflammation and metabolism: molecular mechanisms and clinical implication

C1q/tumor necrosis factor (TNF) related proteins (CTRPs) is a newly discovered adipokine family with conservative structure and ubiquitous distribution and is secreted by adipose tissues. Recently, CTRPs have attracted increasing attention due to the its wide-ranging effects upon inflammation and metabolism. To-date, 15 members of CTRPs (CTRP1-15) with the characteristic C1q domain have been characterized. Earlier in-depth phenotypic analyses of mouse models of CTRPs deficiency have also unveiled ample function of CTRPs in inflammation and metabolism. This review focuses on the rise of CTRPs, with a special emphasis on the latest discoveries with regards to the effects of the CTRP family on inflammation and metabolism as well as related diseases. We first introduced the structure of characteristic domain and polymerization of CTRPs to reveal its pleiotropic biological functions. Next, intimate association of CTRP family with inflammation and metabolism, as well as the involvement of CTRPs as nodes in complex molecular networks, were elaborated. With expanding membership of CTRP family, the information presented here provides new perspectives for therapeutic strategies to improve inflammatory and metabolic abnormalities.

Inhibition of transglutaminase 2 (TG2) ameliorates ventricular fibrosis in isoproterenol-induced heart failure in rats

AIMS

Transglutaminase (TG) inhibitors represent promising therapeutic interventions in cardiac fibrosis and related dysfunctions. However, it remains unknown how TG inhibition, TG2 in particular, affects the signaling systems that drive pathological fibrosis. This study aimed to examine the effect TG inhibition by cystamine on the progression of isoproterenol (ISO)-induced cardiac fibrosis and dysfunction in rats.

MATERIALS AND METHODS

Cardiac fibrosis was established by intraperitoneal injection of ISO to rats (ISO group), followed by 6 weeks of cystamine injection (ISO + Cys group). The control groups were administered normal saline alone or with cystamine. Hemodynamics, lipid profile, liver enzymes, urea, and creatinine were assessed in conjunction with heart failure markers (serum NT-proANP and cTnI). Left ventricular (LV) and atrial (LA) fibrosis, total collagen content, and mRNA expression of profibrotic markers including TG2 were quantified by Masson's trichrome staining, LC-MS/MS and quantitative PCR, respectively.

KEY FINDINGS

Cystamine administration to ISO rats significantly decreased diastolic and mean arterial pressures, total cholesterol, triglycerides, LDL, liver enzymes, urea, and creatinine levels, while increasing HDL. NT-proANP and cTnI serum levels remained unchanged. In LV tissues, significant reductions in ISO-induced fibrosis and elevated total collagen content were achieved after cystamine treatment, together with a reduction in TG2 concentration. Reduced mRNA expression of several profibrotic genes (COL1A1, FN1, MMP-2, CTGF, periostin, CX43) was also evidenced in LV tissues of ISO rats upon cystamine administration, whereas TGF-β1 expression was depressed in LA tissues. Cystamine decreased TG2 mRNA expression in the LV of control rats, while LV expression of TG2 was relatively low in ISO rats irrespective of cystamine treatment.

SIGNIFICANCE

TG2 inhibition by cystamine in vivo exerted cardioprotective effects against ISO-induced cardiac fibrosis in rats decreasing the LV abundance of several profibrotic markers and the content of TG2 and collagen, suggesting that TG2 pharmacological inhibition could be beneficial to alleviate cardiac fibrosis.

LINC01013 Is a Determinant of Fibroblast Activation and Encodes a Novel Fibroblast-Activating Micropeptide

Myocardial fibrosis confers an almost threefold mortality risk in heart disease. There are no prognostic therapies and novel therapeutic targets are needed. Many thousands of unannotated small open reading frames (smORFs) have been identified across the genome with potential to produce micropeptides (< 100 amino acids). We sought to investigate the role of smORFs in myocardial fibroblast activation.Analysis of human cardiac atrial fibroblasts (HCFs) stimulated with profibrotic TGFβ1 using RNA sequencing (RNA-Seq) and ribosome profiling (Ribo-Seq) identified long intergenic non-coding RNA LINC01013 as TGFβ1 responsive and containing an actively translated smORF. Knockdown of LINC01013 using siRNA reduced expression of profibrotic markers at baseline and blunted their response to TGFβ1. In contrast, overexpression of a codon-optimised smORF invoked a profibrotic response comparable to that seen with TGFβ1 treatment, whilst FLAG-tagged peptide associated with the mitochondria.Together, these data support a novel LINC01013 smORF micropeptide-mediated mechanism of fibroblast activation. TGFβ1 stimulation of atrial fibroblasts induces expression of LINC01013, whose knockdown reduces fibroblast activation. Overexpression of a smORF contained within LINC01013 localises to mitochondria and activates fibroblasts.

Signaling Pathways and Potential Therapeutic Strategies in Cardiac Fibrosis

Cardiac fibrosis constitutes irreversible necrosis of the heart muscle as a consequence of different acute (myocardial infarction) or chronic (diabetes, hypertension, …) diseases but also due to genetic alterations or aging. Currently, there is no curative treatment that is able to prevent or attenuate this phenomenon that leads to progressive cardiac dysfunction and life-threatening outcomes. This review summarizes the different targets identified and the new strategies proposed to fight cardiac fibrosis. Future directions, including the use of exosomes or nanoparticles, will also be discussed.

Identification of novel biomarkers involved in doxorubicin-induced acute and chronic cardiotoxicity, respectively, by integrated bioinformatics

Background

The mechanisms of doxorubicin (DOX) cardiotoxicity were complex and controversial, with various contradictions between experimental and clinical data. Understanding the differences in the molecular mechanism between DOX-induced acute and chronic cardiotoxicity may be an ideal entry point to solve this dilemma.

Methods

Mice were injected intraperitoneally with DOX [(20 mg/kg, once) or (5 mg/kg/week, three times)] to construct acute and chronic cardiotoxicity models, respectively. Survival record and ultrasound monitored the cardiac function. The corresponding left ventricular (LV) myocardium tissues were analyzed by RNA-seq to identify differentially expressed genes (DEGs). Gene Ontology (GO), Kyoto Encyclopedia of Gene and Genome (KEGG), and Gene Set Enrichment Analysis (GSEA) found the key biological processes and signaling pathways. DOX cardiotoxicity datasets from the Gene expression omnibus (GEO) database were combined with RNA-seq to identify the common genes. Cytoscape analyzed the hub genes, which were validated by quantitative real-time PCR. ImmuCo and ImmGen databases analyzed the correlations between hub genes and immunity-relative markers in immune cells. Cibersort analyzed the immune infiltration and correlations between the hub genes and the immune cells. Logistic regression, receiver operator characteristic curve, and artificial neural network analysis evaluated the diagnosis ability of hub genes for clinical data in the GEO dataset.

Results

The survival curves and ultrasound monitoring demonstrated that cardiotoxicity models were constructed successfully. In the acute model, 788 DEGs were enriched in the activated metabolism and the suppressed immunity-associated signaling pathways. Three hub genes (Alas1, Atp5g1, and Ptgds) were upregulated and were negatively correlated with a colony of immune-activating cells. However, in the chronic model, 281 DEGs showed that G protein-coupled receptor (GPCR)-related signaling pathways were the critical events. Three hub genes (Hsph1, Abcb1a, and Vegfa) were increased in the chronic model. Furthermore, Hsph1 combined with Vegfa was positively correlated with dilated cardiomyopathy (DCM)-induced heart failure (HF) and had high accuracy in the diagnosis of DCM-induced HF (AUC = 0.898, P = 0.000).

Conclusion

Alas1, Atp5g1, and Ptgds were ideal biomarkers in DOX acute cardiotoxicity. However, Hsph1 and Vegfa were potential biomarkers in the myocardium in the chronic model. Our research, first, provided bioinformatics and clinical evidence for the discovery of the differences in mechanism and potential biomarkers of DOX-induced acute and chronic cardiotoxicity to find a therapeutic strategy precisely.

The Multiple Roles of Periostin in Non-Neoplastic Disease

Periostin, identified as a matricellular protein and an ECM protein, plays a central role in non-neoplastic diseases. Periostin and its variants have been considered to be normally involved in the progression of most non-neoplastic diseases, including brain injury, ocular diseases, chronic rhinosinusitis, allergic rhinitis, dental diseases, atopic dermatitis, scleroderma, eosinophilic esophagitis, asthma, cardiovascular diseases, lung diseases, liver diseases, chronic kidney diseases, inflammatory bowel disease, and osteoarthrosis. Periostin interacts with protein receptors and transduces signals primarily through the PI3K/Akt and FAK two channels as well as other pathways to elicit tissue remodeling, fibrosis, inflammation, wound healing, repair, angiogenesis, tissue regeneration, bone formation, barrier, and vascular calcification. This review comprehensively integrates the multiple roles of periostin and its variants in non-neoplastic diseases, proposes the utility of periostin as a biological biomarker, and provides potential drug-developing strategies for targeting periostin.

Periostin as a Biomarker in the Setting of Glomerular Diseases-A Review of the Current Literature

Chronic kidney disease (CKD) is a highly prevalent and potential progressive condition with life-threatening consequences. Glomerular diseases (glomerulopathies) are causes of CKD that are potentially amenable by specific therapies. Significant resources have been invested in the identification of novel biomarkers of CKD progression and new targets for treatment. By using experimental models of kidney diseases, periostin has been identified amongst the most represented matricellular proteins that are commonly involved in the inflammation and fibrosis that characterize progressive kidney diseases. Periostin is highly expressed during organogenesis, with scarce expression in mature healthy tissues, but it is upregulated in multiple disease settings characterized by tissue injury and remodeling. Periostin was the most highly expressed matriceal protein in both animal models and in patients with glomerulopathies. Given that periostin is readily secreted from injury sites, and the variations in its humoral levels compared to the normal state were easily detectable, its potential role as a biomarker is suggested. Moreover, periostin expression was correlated with the degree of histological damage and with kidney function decline in patients with CKD secondary to both inflammatory (IgA nephropathy) and non-inflammatory (membranous nephropathy) glomerulopathies, while also displaying variability secondary to treatment response. The scope of this review is to summarize the existing evidence that supports the role of periostin as a novel biomarker in glomerulopathies.

Experimental study on co-culture of DiI-labeled rat bone marrow mesenchymal stem cells and neonatal rat cardiomyocytes to induce differentiation into cardiomyocyte-like cells

BACKGROUND: Myocardial infarction is a serious clinical disease with high mortality and poor prognosis. Cardiomyocytes (CMs) have limited regeneration abilities after ischemic injury. Their growth and differentiation can be enhanced by contact co-culture with stem cells. OBJECTIVE: The aim was to study the contact co-culture of Dil-labeled bone marrow mesenchymal stem cells (BMSCs) and CMs for inducing differentiation of CMs from stem cells for treating myocardial infarction. METHODS: After contact co-culture, the differentiation of BMSCs into CMs was analyzed qualitatively by detecting myocardial markers (cardiac troponin T and α-smooth muscle actin) using immunofluorescence and quantitatively using flow cytometry. To examine the mechanism, possible gap junctions between BMSCs and CMs were analyzed by detecting gap junction protein connexin 43 (C×43) expression in BMSCs using immunofluorescence. The functionality of gap junctions was analyzed using dye transfer experiments. RESULTS: The results revealed that BMSCs in contact with CMs exhibited myocardial markers and a significant increase in differentiation rate (P < 0.05); they also proved the existence and function of gap junctions between BMSCs and CMs. CONCLUSIONS: It was shown that contact co-culture can induce Dil-labeled BMSCs to differentiate into CM-like cells and examined the principle of gap junction-mediated signaling pathways involved in inducing stem cells to differentiate into cardiomyocytes.

Periostin: an emerging activator of multiple signaling pathways

Matricellular proteins are responsible for regulating the microenvironment, the behaviors of surrounding cells, and the homeostasis of tissues. Periostin (POSTN), a non-structural matricellular protein, can bind to many extracellular matrix proteins through its different domains. POSTN usually presents at low levels in most adult tissues but is highly expressed in pathological sites such as in tumors and inflamed organs. POSTN can bind to diverse integrins to interact with multiple signaling pathways within cells, which is one of its core biological functions. Increasing evidence shows that POSTN can activate the TGF-β, the PI3K/Akt, the Wnt, the RhoA/ROCK, the NF-κB, the MAPK and the JAK pathways to promote the occurrence and development of many diseases, especially cancer and inflammatory diseases. Furthermore, POSTN can interact with some pathways in an upstream and downstream relationship, forming complicated crosstalk. This article focuses on the interactions between POSTN and different signaling pathways in diverse diseases, attempting to explain the mechanisms of interaction and provide novel guidelines for the development of targeted therapies.

Candidate genes and their alternative splicing may be potential biomarkers of acute myocardial infarction: a study of mouse model

Background

Acute myocardial infarction (AMI) is one of the leading causes of death in human being, and an effective diagnostic biomarker is still lacking. Whilst some gene association with AMI has been identified by RNA sequencing (RNA-seq), the relationship between alternative splicing and AMI is not clear.

Methods

We retrieved myocardial tissues within 24 h from mice with induced AMI and sham, and analysed the differentially expressed genes (DEGs) and differential alternative splicing genes (DASGs) by RNA-seq. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and protein interaction network analysis were performed on DEGs-DASGs-overlap genes. PCR was used to verify the expression levels of representative genes and alternative splicing in myocardial tissues of AMI and sham mice.

Results

1367 DEGs were identified, including 242 up-regulated and 1125 down-regulated genes, among which there were 42 DASGs. GO analysis showed that the cellular component was primarily enriched in plasma membrane, cell membrane integrity and extracellular region. The molecular function was enriched in protein binding and metal ion binding. The biological process was primarily enriched in cell adhesion, immune system process and cell differentiation. KEGG analysis showed the enrichment was mainly in JAK-STAT and PI3K-AKT signalling pathway. Postn, Fhl1, and Fn1 were low-expressed while Postn alternative splicing was high-expressed in myocardial tissue of AMI mice, which was consistent with sequencing results.

Conclusions

The pathogenesis of AMI involves differentially expressed genes and differential alternative splicing. These differentially expressed genes and their alternative splicing, especially, Fhl1, Fn1 and Postn may become new biomarkers of AMI.

Flavanol Consumption in Healthy Men Preserves Integrity of Immunological-Endothelial Barrier Cell Functions: Nutri(epi)genomic Analysis

SCOPE

While cocoa flavanol (CF) consumption improves cardiovascular risk biomarkers, molecular mechanisms underlying their protective effects are not understood.

OBJECTIVE

To investigate nutri(epi)genomic effects of CF and identify regulatory networks potential mediating vascular health benefits.

METHODS AND RESULTS

Twenty healthy middle-aged men consume CF (bi-daily 450 mg) or control drinks for 1 month. Microarray analysis identifies 2235 differentially expressed genes (DEG) involved in processes regulating immune response, cell adhesion, or cytoskeleton organization. Distinct patterns of DEG correlate with CF-related changes in endothelial function, arterial stiffness, and blood pressure. DEG profile negatively correlates with expression profiles of cardiovascular disease patients. CF modulated DNA methylation profile of genes implicates in cell adhesion, actin cytoskeleton organization, or cell signaling. In silico docking analyses indicate that CF metabolites have the potential of binding to cell signaling proteins and transcription factors. Incubation of plasma obtained after CF consumption decrease monocyte to endothelial adhesion and dose-dependently increase nitric oxide-dependent chemotaxis of circulating angiogenic cells further validating the biological functions of CF metabolites.

CONCLUSION

In healthy humans, CF consumption may mediate vascular protective effects by modulating gene expression and DNA methylation towards a cardiovascular protective effect, in agreement with clinical results, by preserving integrity of immunological-endothelial barrier functions.

PGE2 protects against heart failure through inhibiting TGF-β1 synthesis in cardiomyocytes and crosstalk between TGF-β1 and GRK2

Inflammation plays a central role in the development of heart failure. Prostaglandin E2 (PGE2) is a key mediator of the inflammatory process in the cardiovascular system. However, the role of PGE2 in heart failure is complex and controversial. A recent report suggested that PGE2 inhibits acute β adrenergic receptor (β-AR) stimulation-enhanced cardiac contractility. The aim of this study was to characterize the influence of PGE2 on chronic β-AR stimulation-induced heart failure. Male C57BL/6 J mice received isoproterenol (ISO) or vehicle for 4 weeks. PGE2 significantly reversed ISO-induced cardiac contractile dysfunction and remodeling. Mechanically, ventricular myocytes were found to be an important source of TGF-β1 in ISO-model and PGE2 ablated TGF-β1 synthesis in cardiomyocytes through inhibition of β-AR activated PKA-CREB signaling. Furthermore, PGE2 significantly suppressed TGF-β1-GRK2 crosstalk-induced pro-hypertrophy and pro-fibrotic signaling in cardiomyocytes and cardiac fibroblasts, respectively. Pharmacological inhibition of GRK2 also attenuated contractile dysfunction and cardiac hypertrophy and fibrosis in ISO-model. These studies elucidate a novel mechanism by which PGE2 reduces TGF-β1 synthesis and its downstream signaling in heart failure and identify PGE2 or TGF-β1-GRK2 crosstalk as plausible therapeutic targets for preventing or treating heart failure induced by chronic β-AR stimulation.

Periostin: biology and function in cancer

Periostin (POSTN), a member of the matricellular protein family, is a secreted adhesion-related protein produced in the periosteum and periodontal ligaments. Matricellular proteins are a nonstructural family of extracellular matrix (ECM) proteins that regulate a wide range of biological processes in both normal and pathological conditions. Recent studies have demonstrated the key roles of these ECM proteins in the tumor microenvironment. Furthermore, periostin is an essential regulator of bone and tooth formation and maintenance, as well as cardiac development. Also, periostin interacts with multiple cell-surface receptors, especially integrins, and triggers signals that promote tumor growth. According to recent studies, these signals are implicated in cancer cell survival, epithelial-mesenchymal transition (EMT), invasion, and metastasis. In this review, we will summarize the most current data regarding periostin, its structure and isoforms, expressions, functions, and regulation in normal and cancerous tissues. Emphasis is placed on its association with cancer progression, and also future potential for periostin-targeted therapeutic approaches will be explored.

Targeting Myocardial Fibrosis—A Magic Pill in Cardiovascular Medicine?

Fibrosis, characterized by an excessive accumulation of extracellular matrix, has long been seen as an adaptive process that contributes to tissue healing and regeneration. More recently, however, cardiac fibrosis has been shown to be a central element in many cardiovascular diseases (CVDs), contributing to the alteration of cardiac electrical and mechanical functions in a wide range of clinical settings. This paper aims to provide a comprehensive review of cardiac fibrosis, with a focus on the main pathophysiological pathways involved in its onset and progression, its role in various cardiovascular conditions, and on the potential of currently available and emerging therapeutic strategies to counteract the development and/or progression of fibrosis in CVDs. We also emphasize a number of questions that remain to be answered, and we identify hotspots for future research.

Serum periostin as a predictor of early recurrence of atrial fibrillation after catheter ablation

Catheter ablation is an effective method of rhythm therapy for atrial fibrillation (AF). AF recurrence is a common problem after catheter ablation. The aim of this study was to investigate influence factors of early recurrence after catheter ablation for AF. One hundred and three consecutive patients with AF were enrolled and underwent catheter ablation. Venous blood (Marked as A) was collected before ablation and left atrial blood (Marked as B) was collected after successful atrial septal puncture to detect serum periostin. After 3 months of follow-up, statistical analysis was made based on the recurrence of AF. 27 (26.2%) patients had a recurrence of atrial arrhythmia after catheter ablation. Patients with recurrent atrial arrhythmia had a larger left atrial volume (162.31 ± 47.76 vs. 141.98 ± 41.64,p = 0.039), and higher serum periostin levels (periostin A. 99.71 ± 16.475 vs. 90.36 ± 13.63, p = 0.005; periostin B. 103.95 ± 13.09 vs. 94.46 ± 15.85, p = 0.006) compared with the non-recurrent group. The numbers of patients with left atrial low-voltage areas (LVAs) were more in the recurrence group (p < 0.001). Left atrial volume, serum periostin and left atrial LVAs were included in univariate and multivariate COX regression analysis. It showed that left atrial LVAs (HR3.81; 95% CI 1.54 to 9.44; p = 0.004) and serum periostin A (HR1.07; 95% CI 1.02 to1.13; p = 0.008) were the independent predictors of AF recurrence. The cut-off value of serum periostin A was 87.95 ng/ ml (AUC, 0.681; sensitivity 88.9% and specificity 53.9%). Kaplan-Meier survival curve showed that the recurrence rate of AF was higher in patients with left atrial LVAs and higher serum periostin. The venous serum periostin level and left atrial LVAs were independent predictors of early recurrence of AF after catheter ablation.

Signaling cascades in the failing heart and emerging therapeutic strategies

Chronic heart failure is the end stage of cardiac diseases. With a high prevalence and a high mortality rate worldwide, chronic heart failure is one of the heaviest health-related burdens. In addition to the standard neurohormonal blockade therapy, several medications have been developed for chronic heart failure treatment, but the population-wide improvement in chronic heart failure prognosis over time has been modest, and novel therapies are still needed. Mechanistic discovery and technical innovation are powerful driving forces for therapeutic development. On the one hand, the past decades have witnessed great progress in understanding the mechanism of chronic heart failure. It is now known that chronic heart failure is not only a matter involving cardiomyocytes. Instead, chronic heart failure involves numerous signaling pathways in noncardiomyocytes, including fibroblasts, immune cells, vascular cells, and lymphatic endothelial cells, and crosstalk among these cells. The complex regulatory network includes protein-protein, protein-RNA, and RNA-RNA interactions. These achievements in mechanistic studies provide novel insights for future therapeutic targets. On the other hand, with the development of modern biological techniques, targeting a protein pharmacologically is no longer the sole option for treating chronic heart failure. Gene therapy can directly manipulate the expression level of genes; gene editing techniques provide hope for curing hereditary cardiomyopathy; cell therapy aims to replace dysfunctional cardiomyocytes; and xenotransplantation may solve the problem of donor heart shortages. In this paper, we reviewed these two aspects in the field of failing heart signaling cascades and emerging therapeutic strategies based on modern biological techniques.

Fibrillin-1 regulates periostin expression during maintenance of periodontal homeostasis

Background/purpose

Human periodontal ligament consists of elastic system fibers, mainly fibrillin-1 (FBN1). Periostin (POSTN) maintains periodontal homeostasis. A previous study showed that the expression of Postn in periodontal ligament cells was decreased in mice underexpressing Fbn1. However, the relationship between FBN1 and POSTN is not fully understood in the context of mechanical stress. FBN1 contributes to transforming growth factor β1 (TGF-β1) activation; TGF-β1 upregulates the expression of POSTN in human periodontal ligament cells. This study examined whether FBN1 contributed to the maintenance of periodontal homeostasis in cultured human periodontal ligament cells.

Materials and methods

Human periodontal ligament fibroblasts (HPDLFs) were exposed to mechanical force via centrifugation. The expression of POSTN was examined by quantitative reverse transcription polymerase chain reaction. The phosphorylation of Smad2 in the TGF-β/Smad signaling pathway was monitored by western blotting.

Results

The expression levels of FBN1 and POSTN were not significantly decreased by centrifugation. However, the expression of POSTN after centrifugation significantly decreased upon knockdown of FBN1. The phosphorylation of Smad2 after centrifugation was decreased, regardless of FBN1 knockdown. Supplementation with 0.1 ng/ml recombinant human TGF-β1 rescued POSTN expression after centrifugation in HPDLFs upon knockdown of FBN1.

Conclusion

FBN1 regulates the expression of POSTN to maintain periodontal homeostasis via TGF-β/Smad signaling during centrifugation.

Protease activated receptor 2 signaling promotes self-renewal and metastasis in colorectal cancer through β-catenin and periostin

The maintenance and expansion of cancer stem-like cells (CSCs) is necessary for metastasis. Although protease-activated receptor 2 (PAR2) is strongly associated with colorectal cancer (CRC) progression, it is unclear how it regulates distal metastasis, and no studies have shown the involvement of CSCs. In this study, we demonstrated that high PAR2 protein expression was correlated with metastatic CRC and poor prognosis in patients with stage III-IV CRC. CSCs from cell lines and patients showed higher levels of PAR2 than that of corresponding non-CSCs, and PAR2 inhibition reduced the CSC properties of the cell lines. Mechanistically, PAR2 inhibition switched the division mode of CSCs from symmetrical to asymmetrical via the ERK/GSK-3β/β-catenin pathway. We also identified periostin as a direct transcriptional target of β-catenin that mediates CSC self-renewal via PAR2 signaling. In a mouse xenograft model, PAR2 knockdown significantly attenuated liver metastasis. Finally, PAR2 expression was positively correlated with β-catenin and periostin in the primary sites of CRC with distant metastasis. Overall, our results indicate that PAR2 activation enhances CSC self-renewal and promotes metastasis through β-catenin and its target gene, periostin, in CRC.

Inhibition of CREB-CBP Signaling Improves Fibroblast Plasticity for Direct Cardiac Reprogramming

Direct cardiac reprogramming of fibroblasts into induced cardiomyocytes (iCMs) is a promising approach but remains a challenge in heart regeneration. Efforts have focused on improving the efficiency by understanding fundamental mechanisms. One major challenge is that the plasticity of cultured fibroblast varies batch to batch with unknown mechanisms. Here, we noticed a portion of in vitro cultured fibroblasts have been activated to differentiate into myofibroblasts, marked by the expression of αSMA, even in primary cell cultures. Both forskolin, which increases cAMP levels, and TGFβ inhibitor SB431542 can efficiently suppress myofibroblast differentiation of cultured fibroblasts. However, SB431542 improved but forskolin blocked iCM reprogramming of fibroblasts that were infected with retroviruses of Gata4, Mef2c, and Tbx5 (GMT). Moreover, inhibitors of cAMP downstream signaling pathways, PKA or CREB-CBP, significantly improved the efficiency of reprogramming. Consistently, inhibition of p38/MAPK, another upstream regulator of CREB-CBP, also improved reprogramming efficiency. We then investigated if inhibition of these signaling pathways in primary cultured fibroblasts could improve their plasticity for reprogramming and found that preconditioning of cultured fibroblasts with CREB-CBP inhibitor significantly improved the cellular plasticity of fibroblasts to be reprogrammed, yielding ~2-fold more iCMs than untreated control cells. In conclusion, suppression of CREB-CBP signaling improves fibroblast plasticity for direct cardiac reprogramming.

Serum Periostin as a Potential Biomarker in Pediatric Patients with Primary Hypertension

Experimental studies suggest that periostin is involved in tissue repair and remodeling. The study aimed to evaluate serum periostin concentration as potential biomarker in pediatric patients with primary hypertension (PH). We measured serum periostin, blood pressure, arterial damage, biochemical, and clinical data in 50 children with PH and 20 age-matched healthy controls. In univariate analysis, children with PH had significantly lower serum periostin compared to healthy peers (35.42 ± 10.43 vs. 42.16 ± 12.82 [ng/mL], p = 0.038). In the entire group of 70 children serum periostin concentration correlated negatively with peripheral, central, and ambulatory blood pressure, as well as with aortic pulse wave velocity (aPWV). In multivariate analysis, periostin level significantly correlated with age (β = -0.614, [95% confidence interval (CI), -0.831--0.398]), uric acid (β = 0.328, [95%CI, 0.124-0.533]), body mass index (BMI) Z-score (β = -0.293, [95%CI, -0.492--0.095]), high-density lipoprotein (HDL)-cholesterol (β = 0.235, [95%CI, 0.054-0.416]), and triglycerides (β = -0.198, [95%CI, -0.394--0.002]). Neither the presence of hypertension nor blood pressure and aPWV influenced periostin level. To conclude, the role of serum periostin as a biomarker of elevated blood pressure and arterial damage in pediatric patients with primary hypertension is yet to be unmasked. Age, body mass index, uric acid, and lipid concentrations are key factors influencing periostin level in pediatric patients.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.

Exosomes Protect Against Acute Myocardial Infarction in Rats by Regulating the Renin-Angiotensin System

The renin-angiotensin system (RAS) has been suggested to play an important role in cardiac remodeling after acute myocardial infarction (AMI). We have confirmed that bone marrow mesenchymal stem cell-derived exosomes (BMSC-EX) had similar types of repair like effects upon tissues as BMSC, but the mechanisms remain unknown. BMSC were cultured to the third generation and were induced to release exosomes. Rats were injected with exosomes (100 μg/mL) or stem cells (1 × 10⁶/mL) through the tail vein immediately after AMI was built, compared to those treated with physiological saline. Thereafter, all groups were analyzed for cardiac function, infarction sizes, and the levels of expression of BNP, ACE, ACE2, AngII, Ang1-7, and other factors in the plasma. After H₂O₂ makes contact with H9C2 cardiomyocytes, cell proliferation activity and apoptotic rates were measured by using CCK8 kits, to facilitate investigation of the effect of exosomes on H9C2 cells. In vivo, the index of cardiac remodeling and cardiac function was improved in both groups of exosomes and stem cells after AMI. Furthermore, exosomes may have helped to regulate the balance of the RAS system, upregulate ACE2-Ang1-7-Mas, and downregulate the ACE-AngII-ATIR pathway. Therefore, its effects were such as to accelerate the conversion of Ang II to Ang 1-7, thereby improving cardiac remodeling and forming sustained myocardial protection. In vitro, exosomal intervention was found to have increased the levels of activity of H9C2 cardiomyocytes under H₂O₂ injury and improved adverse effects of AngII upon H9C2 cells. All procedures for this study were reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) at Guangdong Medical University. BMSC-EX improved cardiac remodeling and cardiac function, and had effects upon RAS system-related factors in plasma. Similarly, BMSC-EX also helped to protect H9C2 cells under attack from H₂O₂ or AngII, and may thus play beneficial roles by facilitating regulation of the balance of the RAS system.

Regenerative cross talk between cardiac cells and macrophages

Aside from the first week postnatal, murine heart regeneration is restricted and responses to damage follow classic fibrotic remodeling. Recent transcriptomic analyses have suggested that significant cross talk with the sterile immune response could maintain a more embryonic-like signaling network that promotes acute, transient responses. However, with age, this response-likely mediated by neonatal yolk sac macrophages-then transitions to classical macrophage-mediated, cardiac fibroblast (CF)-based remodeling of the extracellular matrix (ECM) after myocardial infarction (MI). The molecular mechanisms that govern the change with age and drive fibrosis via inflammation are poorly understood. Using multiple ribonucleic acid sequencing (RNA-Seq) datasets, we attempt to resolve the relative contributions of CFs and macrophages in the bulk-healing response of regenerative (postnatal day 1) and nonregenerative hearts (postnatal day 8+). We performed an analysis of bulk RNA-Seq datasets from myocardium and cardiac fibroblasts as well as a single-cell RNA-Seq dataset from cardiac macrophages. MI-specific pathway differences revealed that nonregenerative hearts generated more ECM and had larger matricellular responses correlating with inflammation, produced greater chemotactic gradients to recruit macrophages, and expressed receptors for danger-associated molecular patterns at higher levels than neonates. These changes could result in elevated stress-response pathways compared with neonates, converging at NF-κB and activator protein-1 (AP-1) signaling. Profibrotic gene programs, which greatly diverge on day 3 post MI, lay the foundation for chronic fibrosis, and thus postnatal hearts older than 7 days typically exhibit significantly less regeneration. Our analyses suggest that the macrophage ontogenetic shift in the heart postnatally could result in detrimental stress signaling that suppresses regeneration.NEW & NOTEWORTHY Immediately postnatal mammalian hearts are able to regenerate after infarction, but the cells, pathways, and molecules that regulate this behavior are unclear. By comparing RNA-Seq datasets from regenerative mouse hearts and older, nonregenerative hearts, we are able to identify biological processes that are hallmarks of regeneration. We find that sterile inflammatory processes are upregulated in nonregenerative hearts, initiating profibrotic gene programs 3 days after myocardial infarction that can cause myocardial disease.

Asenapine maleate inhibits angiotensin II-induced proliferation and activation of cardiac fibroblasts via the ROS/TGFβ1/MAPK signaling pathway

BACKGROUND

Cardiac fibrosis will increase wall stiffness and diastolic dysfunction, which will eventually lead to heart failure. Asenapine maleate (AM) is widely used in the treatment of schizophrenia. In the current study, we explored the potential mechanism underlying the role of AM in angiotensin II (Ang II)-induced cardiac fibrosis.

METHODS

Cardiac fibroblasts (CFs) were stimulated using Ang II with or without AM. Cell proliferation was measured using the cell counting kit-8 assay and the Cell-Light EdU Apollo567 In Vitro Kit. The expression levels of proliferating cell nuclear antigen (PCNA) and α-smooth muscle actin (α-SMA) were detected using immunofluorescence or western blotting. At the protein level, the expression levels of the components of the transforming growth factor beta 1 (TGFβ1)/mitogen-activated protein kinase (MAPK) signaling pathway were also detected.

RESULTS

After Ang II stimulation, TGFβ1, TGFβ1 receptor, α-SMA, fibronectin (Fn), collagen type I (Col1), and collagen type III (Col3) mRNA levels increased; the TGFβ1/MAPK signaling pathway was activated in CFs. After AM pretreatment, cell proliferation was inhibited, the numbers of PCNA -positive cells and the levels of cardiac fibrosis markers decreased. The activity of the TGFβ1/MAPK signaling pathway was also inhibited. Therefore, AM can inhibit cardiac fibrosis by blocking the Ang II-induced activation through TGFβ1/MAPK signaling pathway.

CONCLUSIONS

This is the first report to demonstrate that AM can inhibit Ang II-induced cardiac fibrosis by down-regulating the TGFβ1/MAPK signaling pathway. In this process, AM inhibited the proliferation and activation of CFs and reduced the levels of cardiac fibrosis markers. Thus, AM represents a potential treatment strategy for cardiac fibrosis.

Antibody-mediated neutralization of IL11 signalling reduces ERK activation and cardiac fibrosis in a mouse model of severe pressure overload

Interleukin-11 (IL11) is important for fibroblast-to-myofibroblast transformations. Here, we examined the signalling and phenotypic effects of inhibiting IL11 signalling using neutralizing antibodies against IL11 or its cognate receptor (IL11RA) in a mouse model of acute and severe pressure overload. C57BL/6J mice underwent ascending aortic constriction (AAC) surgery and were randomized to anti-IL11, anti-IL11RA, or isotype control antibodies (20 mg/kg, bi-weekly for 2 weeks). AAC surgery induced the expression of IL11, IL11RA and extracellular matrix (ECM) genes that was associated with cardiac hypertrophy and aortic remodelling. Inhibition of IL11 signalling reduced AAC-induced cardiac fibrosis and ECM gene expression as well as ERK1/2 phosphorylation but had no effect on cardiac hypertrophy. STAT3 was phosphorylated in the hearts of AAC-treated mice but this was unrelated to IL11 activity, which we confirmed in mouse cardiac fibroblasts in vitro. These data highlight that blocking IL11 signalling reduces cardiac fibrosis due to severe pressure overload and suggests ERK, but not STAT3, activity as the relevant underlying signalling pathway.

Role of the Renin-Angiotensin-Aldosterone System in Dystrophin-Deficient Cardiomyopathy

Dystrophin-deficient cardiomyopathy (DDC) is currently the leading cause of death in patients with dystrophinopathies. Targeting myocardial fibrosis (MF) has become a major therapeutic goal in order to prevent the occurrence of DDC. We aimed to review and summarize the current evidence about the role of the renin-angiotensin-aldosterone system (RAAS) in the development and perpetuation of MF in DCC. We conducted a comprehensive search of peer-reviewed English literature on PubMed about this subject. We found increasing preclinical evidence from studies in animal models during the last 20 years pointing out a central role of RAAS in the development of MF in DDC. Local tissue RAAS acts directly mainly through its main fibrotic component angiotensin II (ANG2) and its transducer receptor (AT1R) and downstream TGF-b pathway. Additionally, it modulates the actions of most of the remaining pro-fibrotic factors involved in DDC. Despite limited clinical evidence, RAAS blockade constitutes the most studied, available and promising therapeutic strategy against MF and DDC. Conclusion: Based on the evidence reviewed, it would be recommendable to start RAAS blockade therapy through angiotensin converter enzyme inhibitors (ACEI) or AT1R blockers (ARBs) alone or in combination with mineralocorticoid receptor antagonists (MRa) at the youngest age after the diagnosis of dystrophinopathies, in order to delay the occurrence or slow the progression of MF, even before the detection of any cardiovascular alteration.

RAS inhibition in resident fibroblast biology

Angiotensin II (Ang II) is a primary mediator of profibrotic signaling in the heart and more specifically, the cardiac fibroblast. Ang II-mediated cardiomyocyte hypertrophy in combination with cardiac fibroblast proliferation, activation, and extracellular matrix production compromise cardiac function and increase mortality in humans. Profibrotic actions of Ang II are mediated by increasing production of fibrogenic mediators (e.g. transforming growth factor beta, scleraxis, osteopontin, and periostin), recruitment of immune cells, and via increased reactive oxygen species generation. Drugs that inhibit Ang II production or action, collectively referred to as renin angiotensin system (RAS) inhibitors, are first line therapeutics for heart failure. Moreover, transient RAS inhibition has been found to persistently alter hypertensive cardiac fibroblast responses to injury providing a useful tool to identify novel therapeutic targets. This review summarizes the profibrotic actions of Ang II and the known impact of RAS inhibition on cardiac fibroblast phenotype and cardiac remodeling.

MicroRNA-21 Mediates a Positive Feedback on Angiotensin II-Induced Myofibroblast Transformation

Objective

Post myocardial infarction (MI) fibrosis has been identified as an important factor in the progression of heart failure. Previous studies have revealed that microRNA-21 (miR-21) plays an important role in the pathogenesis of fibrosis. The purpose of this study was to explore the role of miR-21 in post-MI cardiac fibrosis.

Material and Methods

MI was established in wild-type (WT) and miR-21 knockout (KO) mice. Primary mice cardiac fibroblasts (CFs) were isolated from WT and miR-21 KO mice and were treated with angiotensin II (Ang II) or Sprouty1 (Spry1) siRNA. Histological analysis and echocardiography were used to determine the extent of fibrosis and cardiac function.

Results

Compared with WT mice, miR-21 KO mice displayed smaller fibrotic areas and decreased expression of fibrotic markers and inflammatory cytokines. In parallel, Ang II-induced myofibroblasts transformation was partially inhibited upon miR-21 KO in primary CFs. Mechanistically, we found that the expression of Spry1, a previously reported target of miR-21, was markedly increased in miR-21 KO mice post MI, further inhibiting ERK1/2 activation. In vitro studies showed that Ang II activated ERK1/2/TGF-β/Smad2/3 pathway. Phosphorylated Smad2/3 further enhanced the expression of α-SMA and FAP and may promote the maturation of miR-21, thereby downregulating Spry1. Additionally, these effects of miR-21 KO on fibrosis were reversed by siRNA-mediated knockdown of Spry1.

Conclusion

Our findings suggest that miR-21 promotes post-MI fibrosis by targeting Spry1. Furthermore, it mediates a positive feedback on Ang II, thereby inducing the ERK/TGF-β/Smad pathway. Therefore, targeting the miR-21–Spry1 axis may be a promising therapeutic option for ameliorating post-MI cardiac fibrosis.

The role of Smad signaling cascades in cardiac fibrosis

Most myocardial pathologic conditions are associated with cardiac fibrosis, the expansion of the cardiac interstitium through deposition of extracellular matrix (ECM) proteins. Although replacement fibrosis plays a reparative role after myocardial infarction, excessive, unrestrained or dysregulated myocardial ECM deposition is associated with ventricular dysfunction, dysrhythmias and adverse prognosis in patients with heart failure. The members of the Transforming Growth Factor (TGF)-β superfamily are critical regulators of cardiac repair, remodeling and fibrosis. TGF-βs are released and activated in injured tissues, bind to their receptors and transduce signals in part through activation of cascades involving a family of intracellular effectors the receptor-activated Smads (R-Smads). This review manuscript summarizes our knowledge on the role of Smad signaling cascades in cardiac fibrosis. Smad3, the best-characterized member of the family plays a critical role in activation of a myofibroblast phenotype, stimulation of ECM synthesis, integrin expression and secretion of proteases and anti-proteases. In vivo, fibroblast Smad3 signaling is critically involved in scar organization and exerts matrix-preserving actions. Although Smad2 also regulates fibroblast function in vitro, its in vivo role in rodent models of cardiac fibrosis seems more limited. Very limited information is available on the potential involvement of the Smad1/5/8 cascade in cardiac fibrosis. Dissection of the cellular actions of Smads in cardiac fibrosis, and identification of patient subsets with overactive or dysregulated myocardial Smad-dependent fibrogenic responses are critical for design of successful therapeutic strategies in patients with fibrosis-associated heart failure.

Role of periostin in ECRS

Periostin, an extracelluar matrix protein belonging to the fasciclin family, has been reported to play a key role in the process of Th2-inflammation disease. As eoshinophilic chronic rhinosinusitis has a higher incident rate, studies show that periostin has participated in the process of inflammation and remodeling. This review mainly to summarize researches of periostin in ECRS and to investigate the clinical significance and expression of periostin.

Transcatheter aortic valve replacements alter circulating serum factors to mediate myofibroblast deactivation

The transcatheter aortic valve replacement (TAVR) procedure has emerged as a minimally invasive treatment for patients with aortic valve stenosis (AVS). However, alterations in serum factor composition and biological activity after TAVR remain unknown. Here, we quantified the systemic inflammatory effects of the TAVR procedure and hypothesized that alterations in serum factor composition would modulate valve and cardiac fibrosis. Serum samples were obtained from patients with AVS immediately before their TAVR procedure (pre-TAVR) and about 1 month afterward (post-TAVR). Aptamer-based proteomic profiling revealed alterations in post-TAVR serum composition, and ontological analysis identified inflammatory macrophage factors implicated in myofibroblast activation and deactivation. Hydrogel biomaterials used as valve matrix mimics demonstrated that post-TAVR serum reduced myofibroblast activation of valvular interstitial cells relative to pre-TAVR serum from the same patient. Transcriptomics and curated network analysis revealed a shift in myofibroblast phenotype from pre-TAVR to post-TAVR and identified p38 MAPK signaling as one pathway involved in pre-TAVR–mediated myofibroblast activation. Post-TAVR serum deactivated valve and cardiac myofibroblasts initially exposed to pre-TAVR serum to a quiescent fibroblast phenotype. Our in vitro deactivation data correlated with patient disease severity measured via echocardiography and multimorbidity scores, and correlations were dependent on hydrogel stiffness. Sex differences in cellular responses to male and female sera were also observed and may corroborate clinical observations regarding sex-specific TAVR outcomes. Together, alterations in serum composition after TAVR may lead to an antifibrotic fibroblast phenotype, which suggests earlier interventions may be beneficial for patients with advanced AVS to prevent further disease progression.

Transcatheter aortic valve replacement alters a patient’s serum proteome, reversing valvular interstitial cell and cardiac myofibroblast activation.

Aortic valve stenosis (narrowing of the aortic valve) contributes to inadequate blood flow, fibrosis, hypertrophy, and, ultimately, heart failure. Transcatheter aortic valve replacement (TAVR) improves blood flow, but little is known about cardiac remodeling after the procedure. Aguado and colleagues performed proteomics on serum samples collected from patients before and after TAVR and studied the effects of serum on valve and cardiac cells using hydrogel culture platforms. A role for p38 MAPK signaling in activating cells was identified using pre-TAVR serum, whereas post-TAVR serum returned cells to a quiescent state. Along with preliminary insights into sex-specific differences, the authors’ research supports a role for TAVR-induced alteration of circulating inflammatory cytokines in regulating valve cell phenotype.

Quantification of uncertainty in a new network model of pulmonary arterial adventitial fibroblast pro-fibrotic signalling

Here, we present a novel network model of the pulmonary arterial adventitial fibroblast (PAAF) that represents seven signalling pathways, confirmed to be important in pulmonary arterial fibrosis, as 92 reactions and 64 state variables. Without optimizing parameters, the model correctly predicted 80% of 39 results of input-output and inhibition experiments reported in 20 independent papers not used to formulate the original network. Parameter uncertainty quantification (UQ) showed that this measure of model accuracy is robust to changes in input weights and half-maximal activation levels (EC50), but is more affected by uncertainty in the Hill coefficient (n), which governs the biochemical cooperativity or steepness of the sigmoidal activation function of each state variable. Epistemic uncertainty in model structure, due to the reliance of some network components and interactions on experiments using non-PAAF cell types, suggested that this source of uncertainty had a smaller impact on model accuracy than the alternative of reducing the network to only those interactions reported in PAAFs. UQ highlighted model parameters that can be optimized to improve prediction accuracy and network modules where there is the greatest need for new experiments. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.

Exogenous NAD+ Stimulates MUC2 Expression in LS 174T Goblet Cells via the PLC-Delta/PTGES/PKC-Delta/ERK/CREB Signaling Pathway

BACKGROUND

MUC2, a major component of the mucus layer in the intestine, is associated with antimicrobial activity and gut immune system function. Currently, mucin is mainly known for its critical function in defense against toxic molecules and pathogens. In this study, we investigated the stimulatory effects of exogenous nicotinamide adenine dinucleotide (NAD+) on the expression of MUC2 in LS 174T goblet cells.

METHODS

Genes related to MUC2 synthesis were measured by quantitative real-time PCR (qPCR). To analyze the gene expression profiles of NAD+-treated LS 174T goblet cells, RNA sequencing was performed. MUC2 expression in the cells and secreted MUC2 were measured by immunocytochemistry (ICC) and ELISA, respectively.

RESULTS

NAD+ significantly stimulated MUC2 expression at mRNA and protein levels and increased the secretion of MUC2. Through RNA sequencing, we found that the expression of genes involved in arachidonic acid metabolism increased in NAD+-treated cells compared with the negative control cells. NAD+ treatment increased phospholipase C (PLC)-δ and prostaglandin E synthase (PTGES) expression, which was inhibited by the appropriate inhibitors. Among the protein kinase C (PKC) isozymes, PKC-δ was involved in the increase in MUC2 expression. In addition, extracellular signal-regulated kinase (ERK)1/2 and cyclic AMP (cAMP) response element-binding protein (CREB) transcript levels were higher in NAD+-treated cells than in the negative control cells, and the enhanced levels of phosphorylated CREB augmented MUC2 expression.

CONCLUSIONS

Exogenous NAD+ increases MUC2 expression by stimulating the PLC-δ/PTGES/PKC-δ/ERK/CREB signaling pathway.

Angiotensin II represses Npr1 expression and receptor function by recruitment of transcription factors CREB and HSF-4a and activation of HDACs

The two vasoactive hormones, angiotensin II (ANG II; vasoconstrictive) and atrial natriuretic peptide (ANP; vasodilatory) antagonize the biological actions of each other. ANP acting through natriuretic peptide receptor-A (NPRA) lowers blood pressure and blood volume. We tested hypothesis that ANG II plays critical roles in the transcriptional repression of Npr1 (encoding NPRA) and receptor function. ANG II significantly decreased NPRA mRNA and protein levels and cGMP accumulation in cultured mesangial cells and attenuated ANP-mediated relaxation of aortic rings ex vivo. The transcription factors, cAMP-response element-binding protein (CREB) and heat-shock factor-4a (HSF-4a) facilitated the ANG II-mediated repressive effects on Npr1 transcription. Tyrosine kinase (TK) inhibitor, genistein and phosphatidylinositol 3-kinase (PI-3K) inhibitor, wortmannin reversed the ANG II-dependent repression of Npr1 transcription and receptor function. ANG II enhanced the activities of Class I histone deacetylases (HDACs 1/2), thereby decreased histone acetylation of H3K9/14ac and H4K8ac. The repressive effect of ANG II on Npr1 transcription and receptor signaling seems to be transduced by TK and PI-3K pathways and modulated by CREB, HSF-4a, HDACs, and modified histones. The current findings suggest that ANG II-mediated repressive mechanisms of Npr1 transcription and receptor function may provide new molecular targets for treatment and prevention of hypertension and cardiovascular diseases.

Dissection of mechanisms of Chinese medicinal formula Si-Miao-Yong-an decoction protects against cardiac hypertrophy and fibrosis in isoprenaline-induced heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Si-Miao-Yong-An decoction (SMYAD) is a traditional Chinese herbal formulation. SMYAD first appeared in the Eastern Han Dynasty according to the "Shen Yi Mi Zhuan". Then the formula was recorded in the "Yan Fang Xin Bian" edited by medical scientist Bao Xiangao in the Qing Dynasty. This well-known prescription has been traditionally used for gangrene and vascular vasculitis. It is mainly used for cardiovascular and endocrine diseases in current clinical applications and research.

AIM OF STUDY

In this study, the potential mechanisms of SMYAD against cardiac fibrosis and hypertrophy in the β-adrenoceptor agonist isoprenaline induced heart failure model were investigated.

MATERIALS AND METHODS

The heart failure animal model was established via injected isoprenaline in rats. Echocardiography was used to detect the structure and function of the heart. HE staining and Masson's trichrome staining was performed to assess myocardial tissue morphology. The serum biochemical indexes were detected by dedicated biochemical kit. BNP was tested by ELISA kit. The levels of mRNA were detected by RT-qPCR. Cardiomyocyte morphology was assessed by immunofluorescence. Phosphorylated and total p38, Akt were analyzed by Western blot. The production of reactive oxygen species (ROS) was tested by CM-H2DCFDA probe. Formula identification of chemical constituents of SMYAD in plasma was disclosed through ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS).

RESULTS

SMYAD was able to improve the heart function in ISO induced heart failure rat model via protecting rat from developing cardiac hypertrophy and fibrosis. SMYAD also decreased plasma expression of these biochemical indexes. It was found that SMYAD could regulate cardiac hypertrophy and fibrosis makers' mRNA levels in vitro and vivo. In addition, SMYAD inhibited the phosphorylation of p38 and Akt, which are key mediators in the pathological process of ISO-induced cardiac hypertrophy and myocardial fibrosis. It also showed that the components of SMYAD in rat plasma exerted myocardial cell protective activity.

CONCLUSION

In summary, SMYAD may comprise more than one active ingredient to the pursuit of combination therapies instead of specifically target a single disease-causing molecule. These experimental results suggest that SMYAD may be a potential drug candidate in diseases of cardiac hypertrophy and myocardial fibrosis caused by β-adrenoceptor abnormalities.

Genetic deletion of Sphk2 confers protection against Pseudomonas aeruginosa mediated differential expression of genes related to virulent infection and inflammation in mouse lung

BACKGROUND

Pseudomonas aeruginosa (PA) is an opportunistic Gram-negative bacterium that causes serious life threatening and nosocomial infections including pneumonia. PA has the ability to alter host genome to facilitate its invasion, thus increasing the virulence of the organism. Sphingosine-1- phosphate (S1P), a bioactive lipid, is known to play a key role in facilitating infection. Sphingosine kinases (SPHK) 1&2 phosphorylate sphingosine to generate S1P in mammalian cells. We reported earlier that Sphk2-/- mice offered significant protection against lung inflammation, compared to wild type (WT) animals. Therefore, we profiled the differential expression of genes between the protected group of Sphk2-/- and the wild type controls to better understand the underlying protective mechanisms related to the Sphk2 deletion in lung inflammatory injury. Whole transcriptome shotgun sequencing (RNA-Seq) was performed on mouse lung tissue using NextSeq 500 sequencing system.

RESULTS

Two-way analysis of variance (ANOVA) analysis was performed and differentially expressed genes following PA infection were identified using whole transcriptome of Sphk2-/- mice and their WT counterparts. Pathway (PW) enrichment analyses of the RNA seq data identified several signaling pathways that are likely to play a crucial role in pneumonia caused by PA such as those involved in: 1. Immune response to PA infection and NF-κB signal transduction; 2. PKC signal transduction; 3. Impact on epigenetic regulation; 4. Epithelial sodium channel pathway; 5. Mucin expression; and 6. Bacterial infection related pathways. Our genomic data suggests a potential role for SPHK2 in PA-induced pneumonia through elevated expression of inflammatory genes in lung tissue. Further, validation by RT-PCR on 10 differentially expressed genes showed 100% concordance in terms of vectoral changes as well as significant fold change.

CONCLUSION

Using Sphk2-/- mice and differential gene expression analysis, we have shown here that S1P/SPHK2 signaling could play a key role in promoting PA pneumonia. The identified genes promote inflammation and suppress others that naturally inhibit inflammation and host defense. Thus, targeting SPHK2/S1P signaling in PA-induced lung inflammation could serve as a potential therapy to combat PA-induced pneumonia.

Oral flavonoid fisetin treatment protects against prolonged high-fat-diet-induced cardiac dysfunction by regulation of multicombined signaling

Excess high-fat diet (HFD) intake predisposes the occurrence of obesity-associated heart injury, but the mechanism is elusive. Fisetin (FIS), as a natural flavonoid, has potential activities to alleviate obesity-induced metabolic syndrome. However, the underlying molecular mechanisms of FIS against HFD-induced cardiac injury remain unclear. The present study was to explore the protective effects of FIS on cardiac dysfunction in HFD-fed mice. We found that FIS alleviated HFD-triggered metabolic disorder by reducing body weight, fasting blood glucose and insulin levels, and insulin resistance. Moreover, FIS supplements significantly alleviated dyslipidemia in both mouse hearts and cardiomyocytes stimulated by metabolic stress. FIS treatment abolished HFD-induced inflammatory response in heart tissues through suppressing TNF receptor-1/TNF receptor-associated factor-2 (Tnfr-1/Traf-2) signaling. Furthermore, FIS induced a strong reduction in the expression of fibrosis-related genes, contributing to the inhibition of fibrosis by inactivating transforming growth factor (Tgf)-β1/Smads/Erk1/2 signaling. Collectively, these results demonstrated that FIS could be a promising therapeutic strategy for the treatment of obesity-associated cardiac injury.

Periostin Promotes Cell Proliferation and Macrophage Polarization to Drive Repair after AKI

BACKGROUND

The matricellular protein periostin has been associated with CKD progression in animal models and human biopsy specimens. Periostin functions by interacting with extracellular matrix components to drive collagen fibrillogenesis and remodeling or by signaling through cell-surface integrin receptors to promote cell adhesion, migration, and proliferation. However, its role in AKI is unknown.

METHODS

We used mice with conditional tubule-specific overexpression of periostin or knockout mice lacking periostin expression in the renal ischemia-reperfusion injury model, and primary cultures of isolated tubular cells in a hypoxia-reoxygenation model.

RESULTS

Tubular epithelial cells showed strong production of periostin during the repair phase of ischemia reperfusion. Periostin overexpression protected mice from renal injury compared with controls, whereas knockout mice showed increased tubular injury and deteriorated renal function. Periostin interacted with its receptor, integrin-β1, to inhibit tubular cell cycle arrest and apoptosis in in vivo and in vitro models. After ischemia-reperfusion injury, periostin-overexpressing mice exhibited diminished expression of proinflammatory molecules and had more F4/80⁺ macrophages compared with knockout mice. Macrophages from periostin-overexpressing mice showed increased proliferation and expression of proregenerative factors after ischemia-reperfusion injury, whereas knockout mice exhibited the opposite. Coculturing a macrophage cell line with hypoxia-treated primary tubules overexpressing periostin, or treating such macrophages with recombinant periostin, directly induced macrophage proliferation and expression of proregenerative molecules.

CONCLUSIONS

In contrast to the detrimental role of periostin in CKD, we discovered a protective role of periostin in AKI. Our findings suggest periostin may be a novel and important mediator of mechanisms controlling renal repair after AKI.

Inhibition of Kirsten-Ras reduces fibrosis and protects against renal dysfunction in a mouse model of chronic folic acid nephropathy

Chronic Kidney Disease is a growing problem across the world and can lead to end-stage kidney disease and cardiovascular disease. Fibrosis is the underlying mechanism that leads to organ dysfunction, but as yet we have no therapeutics that can influence this process. Ras monomeric GTPases are master regulators that direct many of the cytokines known to drive fibrosis to downstream effector cascades. We have previously shown that K-Ras is a key isoform that drives fibrosis in the kidney. Here we demonstrate that K-Ras expression and activation are increased in rodent models of CKD. By knocking down expression of K-Ras using antisense oligonucleotides in a mouse model of chronic folic acid nephropathy we can reduce fibrosis by 50% and prevent the loss of renal function over 3 months. In addition, we have demonstrated in vitro and in vivo that reduction of K-Ras expression is associated with a reduction in Jag1 expression; we hypothesise this is the mechanism by which targeting K-Ras has therapeutic benefit. In conclusion, targeting K-Ras expression with antisense oligonucleotides in a mouse model of CKD prevents fibrosis and protects against renal dysfunction.