Activation of Sonic hedgehog signaling in ventricular cardiomyocytes exerts cardioprotection against ischemia reperfusion injuries

Management of Myocardial Infarction: Emerging Paradigms for the Future

Despite significant advancements in managing acute ST-segment elevation myocardial infarctions, the prevalence of heart failure has not decreased. Emerging paradigms with a focus on reducing infarct size show promising evidence in the improvement of the incidence of heart failure after experiencing acute coronary syndromes. Limiting infarct size has been the focus of multiple clinical trials over the past decades and has led to left ventricular (LV) unloading as a potential mechanism. Contemporary use of microaxial flow devices for LV unloading has suggested improvement in mortality in acute myocardial infarction complicated by cardiogenic shock. This review focuses on clinical data demonstrating evidence of infarct size reduction and highlights ongoing clinical trials that provide a new therapeutic approach to the management of acute myocardial infarction.

Downregulation of HHATL promotes cardiac hypertrophy via activation of SHH/DRP1

HHATL, previously implicated in cardiac hypertrophy in the zebrafish model, has emerged as a prioritized HCM risk gene. We identified six rare mutations in HHATL, present in 6.94 % of nonsarcomeric HCM patients (5/72). Moreover, a decrease of HHATL in the heart tissue from HCM patients and cardiac hypertrophy mouse model using transverse aortic constriction was observed. Despite this, the precise pathogenic mechanisms underlying HHATL-associated cardiac hypertrophy remain elusive. In this study, we observed that HHATL downregulation in H9C2 cells resulted in elevated expression of hypertrophic markers and reactive oxygen species (ROS), culminating in cardiac hypertrophy and mitochondrial dysfunction. Notably, the bioactive form of SHH, SHHN, exhibited a significant increase, while the mitochondrial fission protein dynamin-like GTPase (DRP1) decreased upon HHATL depletion. Intervention with the SHH inhibitor RU-SKI 43 or DRP1 overexpression effectively prevented Hhatl-depletion-induced cardiac hypertrophy, mitigating disruptions in mitochondrial morphology and membrane potential through the SHH/DRP1 axis. In summary, our findings suggest that HHATL depletion activates SHH signaling, reducing DRP1 levels and thereby promoting the expression of hypertrophic markers, ROS generation, and mitochondrial dysfunction, ultimately leading to cardiac hypertrophy. This study provides additional compelling evidence supporting the association of HHATL with cardiac hypertrophy.

Biotherapeutic approaches against cardio-metabolic dysfunctions based on extracellular vesicles

Among the different pathways involved in the cell-to-cell communication, extracellular vesicles (EVs) are defined as key players in the transport of different signalling molecules, such as lipids, proteins, and RNA, from the originating cells to specific target cells. The biogenesis and composition of EVs are complex and confer them a unique ability to more effectively reach tissues and cells as compared to other types of synthetic carriers. Owing to these properties, EVs have been suggested as new therapeutic tools for personalized medicine. Since cardiometabolic diseases have reached pandemic proportions, new therapies are needed to be developed. In this context, EVs appear as promising therapeutic tools against cardiometabolic disorders associated with obesity and diabetes. This review focuses on the latest research on preclinical applications of EVs for cardiometabolic diseases, and draw primarily on our experience in this area.

Hedgehog costimulation during ischemia-reperfusion injury potentiates cytokine and homing responses of CD4+ T cells

Introduction

Ischemia reperfusion injury (IRI) confers worsened outcomes and is an increasing clinical problem in solid organ transplantation. Previously, we identified a "PtchHi" T-cell subset that selectively received costimulatory signals from endothelial cell-derived Hedgehog (Hh) morphogens to mediate IRI-induced vascular inflammation.

Methods

Here, we used multi-omics approaches and developed a humanized mouse model to resolve functional and migratory heterogeneity within the PtchHi population.

Results

Hh-mediated costimulation induced oligoclonal and polyclonal expansion of clones within the PtchHi population, and we visualized three distinct subsets within inflamed, IRI-treated human skin xenografts exhibiting polyfunctional cytokine responses. One of these PtchHi subsets displayed features resembling recently described T peripheral helper cells, including elaboration of IFN-y and IL-21, expression of ICOS and PD-1, and upregulation of positioning molecules conferring recruitment and retention within peripheral but not lymphoid tissues. PtchHi T cells selectively homed to IRI-treated human skin xenografts to cause accelerated allograft loss, and Hh signaling was sufficient for this process to occur.

Discussion

Our studies define functional heterogeneity among a PtchHi T-cell population implicated in IRI.

Pioneering therapies for post-infarction angiogenesis: Insight into molecular mechanisms and preclinical studies

Acute myocardial infarction (MI), despite significant progress in its treatment, remains a leading cause of chronic heart failure and cardiovascular events such as cardiac arrest. Promoting angiogenesis in the myocardial tissue after MI to restore blood flow in the ischemic and hypoxic tissue is considered an effective treatment strategy. The repair of the myocardial tissue post-MI involves a robust angiogenic response, with mechanisms involved including endothelial cell proliferation and migration, capillary growth, changes in the extracellular matrix, and stabilization of pericytes for neovascularization. In this review, we provide a detailed overview of six key pathways in angiogenesis post-MI: the PI3K/Akt/mTOR signaling pathway, the Notch signaling pathway, the Wnt/β-catenin signaling pathway, the Hippo signaling pathway, the Sonic Hedgehog signaling pathway, and the JAK/STAT signaling pathway. We also discuss novel therapeutic approaches targeting these pathways, including drug therapy, gene therapy, protein therapy, cell therapy, and extracellular vesicle therapy. A comprehensive understanding of these key pathways and their targeted therapies will aid in our understanding of the pathological and physiological mechanisms of angiogenesis after MI and the development and application of new treatment strategies.

Therapeutic implication of Sonic Hedgehog as a potential modulator in ischemic injury

Sonic Hedgehog (SHh) is a homology protein that is involved in the modeling and development of embryonic tissues. As SHh plays both protective and harmful roles in ischemia, any disruption in the transduction and regulation of the SHh signaling pathway causes ischemia to worsen. The SHh signal activation occurs when SHh binds to the receptor complex of Ptc-mediated Smoothened (Smo) (Ptc-smo), which initiates the downstream signaling cascade. This article will shed light on how pharmacological modifications to the SHh signaling pathway transduction mechanism alter ischemic conditions via canonical and non-canonical pathways by activating certain downstream signaling cascades with respect to protein kinase pathways, angiogenic cytokines, inflammatory mediators, oxidative parameters, and apoptotic pathways. The canonical pathway includes direct activation of interleukins (ILs), angiogenic cytokines like hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and hypoxia-inducible factor alpha (HIF-), which modulate ischemia. The non-canonical pathway includes indirect activation of certain pathways like mTOR, PI3K/Akt, MAPK, RhoA/ROCK, Wnt/-catenin, NOTCH, Forkhead box protein (FOXF), Toll-like receptors (TLR), oxidative parameters such as GSH, SOD, and CAT, and some apoptotic parameters such as Bcl2. This review provides comprehensive insights that contribute to our knowledge of how SHh impacts the progression and outcomes of ischemic injuries.

The Pathophysiological Role of Platelet-Derived Extracellular Vesicles

Platelets are very abundant in the blood, where they play a role in hemostasis, inflammation, and immunity. When activated, platelets undergo a conformational change that allows the release of numerous effector molecules as well as the production of extracellular vesicles, which are circulating submicron vesicles (10 to 1,000 nm in diameter) released into the extracellular space. Extracellular vesicles are formed by the budding of platelet and they carry some of its contents, including nucleic acids, surface proteins, and organelles. While platelets cannot cross tissue barriers, platelet-derived extracellular vesicles can enter the lymph, bone marrow, and synovial fluid. This allows the transfer of diverse contents carried by these platelet-derived vesicles to cell recipients and organs inaccessible to platelets where they can perform many functions. This review highlights the importance of these platelet-derived extracellular vesicles under different physiological and pathophysiological conditions.

Hedgehog-induced ZFYVE21 promotes chronic vascular inflammation by activating NLRP3 inflammasomes in T cells

The zinc finger protein ZFYVE21 is involved in immune signaling. Using humanized mouse models, primary human cells, and patient samples, we identified a T cell-autonomous role for ZFYVE21 in promoting chronic vascular inflammation associated with allograft vasculopathy. Ischemia-reperfusion injury (IRI) stimulated endothelial cells to produce Hedgehog (Hh) ligands, which in turn induced the production of ZFYVE21 in a population of T memory cells with high amounts of the Hh receptor PTCH1 (PTCHhi cells, CD3+CD4+CD45RO+PTCH1hiPD-1hi), vigorous recruitment to injured endothelia, and increased effector responses in vivo. After priming by interferon-γ (IFN-γ), Hh-induced ZFYVE21 activated NLRP3 inflammasome activity in T cells, which potentiated IFN-γ responses. Hh-induced NLRP3 inflammasomes and T cell-specific ZFYVE21 augmented the vascular sequelae of chronic inflammation in mice engrafted with human endothelial cells or coronary arteries that had been subjected to IRI before engraftment. Moreover, the population of PTCHhi T cells producing high amounts of ZFYVE21 was expanded in patients with renal transplant-associated IRI, and sera from these patients expanded this population in control T cells in a manner that depended on Hh signaling. We conclude that Hh-induced ZFYVE21 activates NLRP3 inflammasomes in T cells, thereby promoting chronic inflammation.

Characterizing the origin of blood plasma proteins from organ tissues in rainbow trout (Oncorhynchus mykiss) using a comparative non-targeted proteomics approach

Protein expression patterns adapt to various cues to meet the needs of an organism. The dynamicity of an organism's proteome can therefore reveal information about an organism's health. Proteome databases contain limited information regarding organisms outside of medicinal biology. The UniProt human and mouse proteomes are extensively reviewed and ∼50 % of both proteomes include tissue specificity, while >99 % of the rainbow trout proteome lacks tissue specificity. This study aimed to expand knowledge on the rainbow trout proteome with a focus on understanding the origin of blood plasma proteins. Blood, brain, heart, liver, kidney, and gills were collected from adult rainbow trout, plasma and tissue proteins were analyzed using liquid chromatography tandem mass spectrometry. Over 10,000 proteins were identified across all groups. Our data indicated that the majority of the plasma proteome is shared amongst multiple tissue types, though 4-7 % of the plasma proteome is uniquely originated from each tissue (gill > heart > liver > kidney > brain).

Hedgehog Morphogens Act as Growth Factors Critical to Pre- and Postnatal Cardiac Development and Maturation: How Primary Cilia Mediate Their Signal Transduction

Primary cilia are crucial for normal cardiac organogenesis via the formation of cyto-architectural, anatomical, and physiological boundaries in the developing heart and outflow tract. These tiny, plasma membrane-bound organelles function in a sensory-integrative capacity, interpreting both the intra- and extra-cellular environments and directing changes in gene expression responses to promote, prevent, and modify cellular proliferation and differentiation. One distinct feature of this organelle is its involvement in the propagation of a variety of signaling cascades, most notably, the Hedgehog cascade. Three ligands, Sonic, Indian, and Desert hedgehog, function as growth factors that are most commonly dependent on the presence of intact primary cilia, where the Hedgehog receptors Patched-1 and Smoothened localize directly within or at the base of the ciliary axoneme. Hedgehog signaling functions to mediate many cell behaviors that are critical for normal embryonic tissue/organ development. However, inappropriate activation and/or upregulation of Hedgehog signaling in postnatal and adult tissue is known to initiate oncogenesis, as well as the pathogenesis of other diseases. The focus of this review is to provide an overview describing the role of Hedgehog signaling and its dependence upon the primary cilium in the cell types that are most essential for mammalian heart development. We outline the breadth of developmental defects and the consequential pathologies resulting from inappropriate changes to Hedgehog signaling, as it pertains to congenital heart disease and general cardiac pathophysiology.

DL-3-n-butylphthalide suppressed autophagy and promoted angiogenesis in rats with vascular dementia by activating the Shh/Ptch1 signaling pathway

DL-3-n-butylphthalide (NBP) has neuroprotective effect on chronic cerebral hypoperfusion animals. Here, we explored the role and underlying mechanism of NBP on autophagy and angiogenesis in rats with vascular dementia (VD). Adult male Sprague-Dawley (SD) rats were subjected to permanent bilateral occlusion of the common carotid arteries (2VO) to establish VD model. These rats were randomly divided into five groups: sham, model, NBP₁₂₀ (120 mg/kg), Shh siRNA (50 nM), and NBP₁₂₀ + Shh siRNA groups. Our results showed that NBP treatment attenuated memory damage in rats with VD, as demonstrated by Morris water maze tests. Immunofluorescence (IF) assay revealed that NBP induced neuronal process length and neuronal activity in hippocampus, which were reversed by Shh silencing. Furthermore, NBP treatment also reduced the expression of autophagy marker proteins B-cell lymphoma-2 interacting protein 1 (Beclin 1) and microtubule-associated protein 1 light chain 3 (LC3), which were further enhanced by Shh silencing. Meanwhile, NBP promoted the angiogenesis, which was accompanied by upregulated vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF)-1, and Angiopoietin (Ang) expression in the hippocampus. And Shh siRNA co-treatment blocked the angiogenesis induced by NBP. Altogether, our results established that NBP treatment suppressed autophagy and improved angiogenesis and neurobehavioral recovery in VD rats partly by activating the Shh/Ptch1 signaling pathway.

The roles of signaling pathways in cardiac regeneration

In recent years, knowledge of cardiac regeneration mechanisms has dramatically expanded. Regeneration can replace lost parts of organs, common among animal species. The heart is commonly considered an organ with terminal development, which has no reparability potential during post-natal life; however, some intrinsic regeneration capacity has been reported for cardiac muscle, which opens novel avenues in cardiovascular disease treatment. Different endogenous mechanisms were studied for cardiac repairing and regeneration in recent decades. Survival, proliferation, inflammation, angiogenesis, cell-cell communication, cardiomyogenesis, and anti-aging pathways are the most important mechanisms that have been studied in this regard. Several in vitro and animal model studies focused on proliferation induction for cardiac regeneration reported promising results. These studies have mainly focused on promoting proliferation signaling pathways and demonstrated various signaling pathways such as Wnt, PI3K/Akt, IGF-1, TGF-β, Hippo, and VEGF signaling cardiac regeneration. Therefore, in this review, we intended to discuss the connection between different critical signaling pathways in cardiac repair and regeneration.

Induced Cardiomyocyte Proliferation: A Promising Approach to Cure Heart Failure

Unlike some lower vertebrates which can completely regenerate their heart, the human heart is a terminally differentiated organ. Cardiomyocytes lost during cardiac injury and heart failure cannot be replaced due to their limited proliferative capacity. Therefore, cardiac injury generally leads to progressive failure. Here, we summarize the latest progress in research on methods to induce cardiomyocyte cell cycle entry and heart repair through the alteration of cardiomyocyte plasticity, which is emerging as an effective strategy to compensate for the loss of functional cardiomyocytes and improve the impaired heart functions.

Graviola mitigates acetic acid-induced ulcerative colitis in rats: insight on apoptosis and Wnt/Hh signaling crosstalk

In this study, we elucidated the potential protective effects of graviola leaves, compared with sulfasalazine, against acetic acid (AA)-induced ulcerative colitis (UC) in rats. Twenty-eight mature male rats were divided into four groups, Sham, Colitis, Colitis/Sulfa, and Colitis/Graviola, and were treated orally with either saline, saline, sulfasalazine (100 mg/kg/day), or graviola (100 mg/kg/day), respectively, for 7 days. On the 4th day, UC was induced by transrectal administration of 4% AA. Colon tissues were excised for macroscopic and histopathological evaluation and immunohistochemical analysis of caspase-3, B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax). Also, levels of oxidative mediators, Wnt family member1 (Wnt1), smoothened (Smo), and glioblastoma-1 (Gli1) were evaluated. Macroscopic and histopathological examination revealed that both graviola and sulfasalazine significantly mitigated colonic damage. Besides, both treatments significantly alleviated AA-induced oxidative stress, as evidenced by reduced nitric oxide (No) and malondialdehyde (MDA) levels and myeloperoxidase (MPO) activity and raised reduced glutathione (GSH) content. Both treatments significantly attenuated AA-induced apoptosis via downregulating the expression of Bax and caspase-3 and upregulating the expression of the anti-apoptotic protein, Bcl-2. Furthermore, downregulation of mRNA expression of Wnt1 with concomitant upregulation of Smo and Gli1 was observed in rats treated with either sulfasalazine or graviola. Based on these observations, graviola may attenuate AA-induced UC, at least partially, by modulating apoptosis and Wingless/Int1 (Wnt) and hedgehog (Hh) signaling crosstalk.

Zebrafish hhatla is involved in cardiac hypertrophy

Cardiac hypertrophy is a compensatory response to pathological stimuli, ultimately progresses to cardiomyopathy, heart failure, or sudden death. Although many signaling pathways have been reported to be involved in the hypertrophic process, it is still not fully clear about the underlying molecular mechanisms for cardiac hypertrophy. Hedgehog acyltransferase-like (Hhatl), a sarcoplasmic reticulum-resident protein, exhibits high expression in the heart and muscle. However, the biological role of Hhatl in the heart remains unknown. In this study, we first found that the expression level of Hhatl is markedly decreased in cardiac hypertrophy. We further studied the role of hhatla, homolog of Hhatl with the zebrafish model. The depletion of hhatla in zebrafish leads to cardiac defects, as well as an enhanced level of hypertrophic markers. Besides, we found that calcineurin signaling participates in hhatla depletion-induced cardiac hypertrophy. Together, these results demonstrate a critical role for hhatla in cardiac hypertrophy.

Linking metabolic dysfunction with cardiovascular diseases: Brn-3b/POU4F2 transcription factor in cardiometabolic tissues in health and disease

Metabolic and cardiovascular diseases are highly prevalent and chronic conditions that are closely linked by complex molecular and pathological changes. Such adverse effects often arise from changes in the expression of genes that control essential cellular functions, but the factors that drive such effects are not fully understood. Since tissue-specific transcription factors control the expression of multiple genes, which affect cell fate under different conditions, then identifying such regulators can provide valuable insight into the molecular basis of such diseases. This review explores emerging evidence that supports novel and important roles for the POU4F2/Brn-3b transcription factor (TF) in controlling cellular genes that regulate cardiometabolic function. Brn-3b is expressed in insulin-responsive metabolic tissues (e.g. skeletal muscle and adipose tissue) and is important for normal function because constitutive Brn-3b-knockout (KO) mice develop profound metabolic dysfunction (hyperglycaemia; insulin resistance). Brn-3b is highly expressed in the developing hearts, with lower levels in adult hearts. However, Brn-3b is re-expressed in adult cardiomyocytes following haemodynamic stress or injury and is necessary for adaptive cardiac responses, particularly in male hearts, because male Brn-3b KO mice develop adverse remodelling and reduced cardiac function. As a TF, Brn-3b regulates the expression of multiple target genes, including GLUT4, GSK3β, sonic hedgehog (SHH), cyclin D1 and CDK4, which have known functions in controlling metabolic processes but also participate in cardiac responses to stress or injury. Therefore, loss of Brn-3b and the resultant alterations in the expression of such genes could potentially provide the link between metabolic dysfunctions with adverse cardiovascular responses, which is seen in Brn-3b KO mutants. Since the loss of Brn-3b is associated with obesity, type II diabetes (T2DM) and altered cardiac responses to stress, this regulator may provide a new and important link for understanding how pathological changes arise in such endemic diseases.

Screening and functional analysis of differentially expressed lncRNAs in rapid atrial pacing dog atrial tissue

PURPOSE

Atrial fibrillation (AF) is one of the most commonly sustained arrhythmias in clinical practice. Long non-coding RNAs (lncRNAs) are gene regulatory elements involved in the development of several diseases. We aimed to explore the expression characteristics of lncRNAs associated with AF.

METHODS

We randomly assigned 12 adult healthy mongrel dogs into a control group and an atrial pacing group. Atrial pacing stimulation was performed at a high frequency of 500 beats per min for 14 consecutive days in the atrial pacing group. HE and Masson staining were used to detect rapid atrial pacing induced atrial fibrosis. Total RNA extraction was performed on dog atrial tissues and was used for high-throughput sequencing of lncRNAs.

RESULTS

A total of 10,310 lncRNAs were detected, and 33 differentially expressed lncRNAs were screened. Among them, 19 lncRNAs were upregulated in the atrial pacing group, and 14 lncRNAs were downregulated. Gene Ontology (GO) classification, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and interaction networks showed that AF-related lncRNAs participate in the regulation of AF in diverse biological processes, cellular components, molecular functions, signaling pathways, and complex interactions with miRNAs and mRNAs. Five differentially expressed lncRNAs were selected for RT-PCR validation, and the verification results were consistent with the results of lncRNA sequencing.

CONCLUSIONS

In summary, our study enhances our understanding of the biological functions of AF-related lncRNAs by screening and analyzing differentially expressed lncRNAs, and the results help to enrich the theoretical basis for the treatment of atrial fibrillation.

Cardioprotective effect of sonic hedgehog ligand in pig models of ischemia reperfusion

Sonic hedgehog (SHH) signaling pathway is involved in embryonic tissue patterning and development. Our previous work identified, in small rodent model of ischemia reperfusion, SHH as a specific efficient tool to reduce infarct size and subsequent arrhythmias by preventing ventricular repolarization abnormalities. The goal of the present study was to provide a proof of concept of the cardioprotective effect of SHH ligand in a porcine model of acute ischemia.

Methods: The antiarrhythmic effect of SHH, either by a recombinant peptide (N-SHH) or shed membrane microparticles harboring SHH ligand (MPs^SHH+), was evaluated in a first set of pigs following a short (25 min) coronary artery occlusion (CAO) followed by 24 hours-reperfusion (CAR) (Protocol A). The infarct-limiting effect was evaluated on a second set of pigs with 40 min of coronary artery occlusion followed by 24 hours reperfusion (Protocol B). Electrocardiogram (ECG) was recorded and arrhythmia's scores were evaluated. Area at risk and myocardial infarct size were quantified.

Results: In protocol A, administration of N-SHH 15 min. after the onset of coronary occlusion significantly reduced the occurrence of ventricular fibrillation compared to control group. Evaluation of arrhythmic score showed that N-SHH treatment significantly reduced the overall occurrence of arrhythmias. In protocol B, massive infarction was observed in control animals. Either N-SHH or MPs^SHH+ treatment reduced significantly the infarct size with a concomitant increase of salvaged area. The reduction in infarct size was both accompanied by a significant decrease in systemic biomarkers of myocardial injury, i.e., cardiac troponin I and fatty acid-binding protein and an increase of eNOS activation.

Conclusions: We show for the first time in a large mammalian model that the activation of the SHH pathway by N-SHH or MPs^SHH+ offers a potent protection of the heart to ischemia-reperfusion by preventing the reperfusion arrhythmias, reducing the infarct area and the circulating levels of biomarkers for myocardial injury. These data open up potentially theranostic prospects for patients suffering from myocardial infarction to prevent the occurrence of arrhythmias and reduce myocardial tissue damage.

Sonic Hedgehog upregulation does not enhance the survival and engraftment of stem cell-derived cardiomyocytes in infarcted hearts

The engraftment of human stem cell-derived cardiomyocytes (hSC-CMs) is a promising treatment for remuscularizing the heart wall post-infarction, but it is plagued by low survival of transplanted cells. We hypothesize that this low survival rate is due to continued ischemia within the infarct, and that increasing the vascularization of the scar will ameliorate the ischemia and improve hSC-CM survival and engraftment. An adenovirus expressing the vascular growth factor Sonic Hedgehog (Shh) was injected into the infarcted myocardium of rats immediately after ischemia/reperfusion, four days prior to hSC-CM injection. By two weeks post-cell injection, Shh treatment had successfully increased capillary density outside the scar, but not within the scar. In addition, there was no change in vessel size or percent vascular volume when compared to cell injection alone. Micro-computed tomography revealed that Shh failed to increase the number and size of larger vessels. It also had no effect on graft size or heart function when compared to cell engraftment alone. Our data suggests that, when combined with the engraftment of hSC-CMs, expression of Shh within the infarct scar and surrounding myocardium is unable to increase vascularization of the infarct scar, and it does not improve survival or function of hSC-CM grafts.

Overexpression of anti-fibrotic factors ameliorates anti-fibrotic properties of Wharton's jelly derived mesenchymal stem cells under oxidative damage

Transplantation with Wharton's jelly derived mesenchymal stem cells (WJ-MSCs) showed great benefits for restoring myocardial function. However, the outcome of WJ-MSCs transplantation was unsuccessful due to multiple factors including oxidative damage. The presence of oxidative stress due to myocardium injury influences fibrous tissue formation, which causes disability of cardiac muscle. Hepatocyte growth factor (HGF), insulin-like growth factor (IGF1), and sonic hedgehog (SHH) are well-known master regulators in anti-fibrosis when secreted by WJ-MSCs. They showed a beneficial role in the recovery of cardiac fibrosis after WJ-MSCs transplantation. This study hypothesizes whether the reduction of the anti-fibrosis property in WJ-MSCs from oxidative damage can be recovered by overexpression of the HGF, IGF1, or SHH gene. Overexpression was attained by transfection of WJ-MSCs with pCMV3-HGF, pCMV3-IGF1, or pCMV3-SHH followed by H2O2 exposure and co-culturing with cardiac fibroblasts. Myofibroblast specific markers comprised of alpha-smooth muscle actin (α-SMA) and collagen type 1 (COL1) were evaluated. The WJ-MSCs treated with H2O2 influenced the expression of myofibroblastic markers, whereas the overexpression of HGF, IGF1 or SHH reduced myofibroblastic formation. These results indicate that the oxidative stress impaired anti-fibrotic property of WJ-MSCs, leads to an increase of myofibroblasts. Overexpression of anti-fibrotic genes restored the endogenous HGF, IGF1, and SHH alleviating improvement of cardiac function.

The Hedgehog Signaling Pathway in Ischemic Tissues

Hedgehog (Hh) proteins are prototypical morphogens known to regulate epithelial/mesenchymal interactions during embryonic development. In addition to its pivotal role in embryogenesis, the Hh signaling pathway may be recapitulated in post-natal life in a number of physiological and pathological conditions, including ischemia. This review highlights the involvement of Hh signaling in ischemic tissue regeneration and angiogenesis, with particular attention to the heart, the brain, and the skeletal muscle. Updated information on the potential role of the Hh pathway as a therapeutic target in the ischemic condition is also presented.

Emerging Therapeutic Targets for Metabolic Syndrome: Lessons from Animal Models

Background:

Metabolic syndrome is a cluster of medical conditions that synergistically increase the risk of heart diseases and diabetes. The current treatment strategy for metabolic syndrome focuses on treating its individual components. A highly effective agent for metabolic syndrome has yet to be developed. To develop a target for metabolic syndrome, the mechanism encompassing different organs - nervous system, pancreas, skeletal muscle, liver and adipose tissue - needs to be understood. Many animal models have been developed to understand the pathophysiology of metabolic syndrome. Promising molecular targets have emerged while characterizing these animals. Modulating these targets is expected to treat some components of metabolic syndrome.

Objective:

o discuss the emerging molecular targets in an animal model of metabolic syndrome.

Methods:

A literature search was performed for the retrieval of relevant articles.

Conclusion:

Multiple genes/pathways that play important role in the development of Metabolic Syndrome are discussed.

Isoflurane Post-conditioning Ameliorates Cerebral Ischemia/Reperfusion Injury by Enhancing Angiogenesis Through Activating the Shh/Gli Signaling Pathway in Rats

Background: Stroke is the second leading cause of death worldwide. Angiogenesis facilitates the formation of microvascular networks and promotes recovery after stroke. The Shh/Gli signaling pathway is implicated in angiogenesis and cerebral ischemia-reperfusion (I/R) injury. This study aimed at investigating the influence of isoflurane (ISO) post-conditioning on brain lesions and angiogenesis after I/R injury.

Methods: Adult male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO), 1.5 h occlusion and 24 h reperfusion (MCAO/R). The ISO post-conditioning group (ISO group) received 1 h ISO post-conditioning when reperfusion was initiated. Neurobehavioral tests, TTC staining, HE staining, Nissl staining, TUNEL staining, immunofluorescence (IF), immunohistochemistry (IH) and Western blot were performed to assess the effect of ISO after I/R injury.

Results: ISO post-conditioning resulted in lower infarct volumes and neurologic deficit scores, higher rate of neurons survival, and less damaged and apoptotic cells after cerebral I/R injury in rats. Meanwhile, ISO post-conditioning significantly increased the expression levels of vascular endothelial growth factor (VEGF) and CD34 in the ischemic penumbra, relative to that in the Sham and I/R groups. However, cyclopamine, the specific inhibitor of the Sonic hedgehog (Shh) signaling pathway, decreased the expression levels of VEGF and CD34, and counteracted the protective effects of ISO post-conditioning against I/R injury in rats.

Conclusions: ISO post-conditioning enhances angiogenesis in vivo partly via the Shh/Gli signaling pathway. Thus, Shh/Gli may represent new therapeutic targets for aiding recovery from stroke.

Microparticles Carrying Sonic Hedgehog Are Increased in Humans with Peripheral Artery Disease

Sonic hedgehog (Shh) is a prototypical angiogenic agent with a crucial role in the regulation of angiogenesis. Experimental studies have shown that Shh is upregulated in response to ischemia. Also, Shh may be found on the surface of circulating microparticles (MPs) and MPs bearing Shh (Shh + MPs) have shown the ability to contribute to reparative neovascularization after ischemic injury in mice. The goal of this study was to test the hypothesis that, in humans with peripheral artery disease (PAD), there is increased number of circulating Shh + MPs. This was done by assessing the number of Shh + MPs in plasma of patients with PAD and control subjects without PAD. We found significantly higher number of Shh + MPs in plasma of subjects with PAD, compared to controls, while the global number of MPs—produced either by endothelial cells, platelets, leukocytes, and erythrocytes—was not different between PAD patients and controls. We also found a significant association between the number of Shh + MPs and the number of collateral vessels in the ischemic limbs of PAD patients. Interestingly, the concentration of Shh protein unbound to MPs—which was measured in MP-depleted plasma—was not different between subjects with PAD and the controls, indicating that, in the setting of PAD, the call for Shh recapitulation does not lead to secretion of protein into the blood but to binding of the protein to the membrane of MPs. These findings provide novel information on Shh signaling during ischemia in humans, with potentially important biological and clinical implications.

Species generalization and differences in Hedgehog pathway regulation of fungiform and circumvallate papilla taste function and somatosensation demonstrated with sonidegib

Species generalization in the profound, modality-specific effects of Hedgehog pathway inhibition (HPI) in taste organ homeostasis and sensation is shown. With the HPI, cancer drug sonidegib, we demonstrate that the rat taste system, in addition to mouse, is regulated by Hedgehog signaling. After sonidegib treatment for 16–36 days in rat, there is loss of taste buds (TB) in soft palate, in fungiform (FP) and circumvallate papillae (CV), and elimination of taste responses from chorda tympani and glossopharyngeal nerves. The retained innervation in FP and CV during HPI cannot sustain TB. Responses to tactile stimuli are not altered, and temperature responses are reduced only after 28 days treatment, demonstrating modality-specific effects. Rat FP and neural effects are similar to those in mouse whereas TB and neural response effects from the rat CV are much more severe. When recovery is introduced in mouse after prolonged, 48 days HPI, the TB in CV are restored whereas those in FP are not. Overall, Hedgehog signaling regulation is shown to generalize to the rat taste system, and the modality-specific controls in taste organ sensation are affirmed. The reported, debilitating taste disturbances in patients who use HPI drugs can be better understood based on these data.

Sonic hedgehog signaling regulates the mammalian cardiac regenerative response

Certain organisms, including zebrafish, are capable of complete cardiac regeneration in response to injury. This response has also been observed in newborn mice, although in this case, the regenerative capacity is lost at approximately one week of age. The mechanisms regulating this short temporal window of cardiac regeneration in mice are not well understood. Here, we show that sonic hedgehog (Shh) signaling modulates the neonatal mouse regenerative response. In particular, we demonstrate that following apical resection of the heart on postnatal day 1, mice activate Shh ligand expression and downstream signaling. This response is largely absent when surgery is performed on non-regenerative, postnatal day 7 pups. Furthermore, an enhanced cardiac regeneration response was detected in ptch heterozygous mice which have a genetically-based constitutive increase in Shh signaling. We further show that Shh ligand is produced in the myocardium by non-myocytes and appears to regulate cardiomyocyte proliferation, as well as the recruitment of monocytes/macrophages to the regenerating area. Finally, we demonstrate that a small molecule activator of Shh signaling promotes heart regeneration, whereas an inhibitor of Shh signaling impairs the regenerative response. Together, these results implicate Shh signaling as a regulator of mammalian heart regeneration and suggest that modulating this pathway may lead to new potential therapies for cardiovascular diseases.

Polydatin ameliorates dextran sulfate sodium-induced colitis by decreasing oxidative stress and apoptosis partially via Sonic hedgehog signaling pathway

BACKGROUND

Inflammation, oxidative stress and epithelial barrier dysfunction have been implicated in inflammatory bowel disease (IBD) pathology. The targeted inhibition of these features may represent a promising therapeutic strategy for IBD. Polydatin is an effective natural antioxidant that possesses strong antioxidant and anti-apoptotic properties. Thus, we studied the protective effects of polydatin treatments on a mouse model of experimental colitis.

METHODS

Acute colitis was experimentally induced by adding 3% dextran sulfate sodium (DSS) to the drinking water provided to mice for 7 days and by administering different doses of polydatin (15, 30, or 45 mg/kg) during the same period. Mice were also treated with the Sonic hedgehog (Shh) pathway inhibitor cyclopamine to estimate the efficacy of polydatin and Shh inhibitors on colitis. The disease activity index (DAI), colon length, histology, levels of oxidative and apoptotic mediators and levels of Shh pathway components were evaluated.

RESULTS

The polydatin treatment significantly attenuated the DAI, colon shortening and histological damage. In addition, polydatin administration effectively decreased malondialdehyde (MDA) levels and increased the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Polydatin also inhibited apoptosis in mice with colitis by downregulating the expression of the pro-apoptotic proteins Bax, caspase 3 and cleaved caspase 3 and increasing the expression of the anti-apoptotic protein Bcl-2. Furthermore, polydatin modulated Shh signaling pathway activation. After polydatin treatment, the main components of the Shh pathway, including Shh, Patched (Ptc), Smoothened (Smo), and glioblastoma-1 (Gli1), were upregulated at the mRNA and protein levels. Blockade of the Shh pathway using cyclopamine abolished the effects of polydatin on mice with colitis.

CONCLUSION

Based on these observations, polydatin may suppress experimental colitis at least partially by regulating the Shh signaling pathway.

Sonic hedgehog signaling regulates hypoxia/reoxygenation-induced H9C2 myocardial cell apoptosis

The sonic hedgehog (Shh) signaling pathway has been reported to protect cells against hypoxia/reoxygenation (H/R) injury; however, the role of Shh and relevant molecular mechanisms remain unclear. In the present study, the rat cardiomyoblast cell line H9C2 was subjected to hypoxia and serum-starvation for 4 h. Cells were subsequently reoxygenated using 95% O₂ and 5% CO₂. Reverse transcription-quantitative polymerase chain reaction was performed to quantify the expression of Shh mRNA, while cell apoptosis was assessed using flow cytometry. Caspase-3 activity and p53 expression were measured by western blotting and an MTT assay was subsequently used to assess cell viability. In addition, reactive oxygen species levels were measured using dichlorofluorescein and H/R-induced changes in the activation of superoxide dismutase, catalase, phosphorylated-endothelial nitric oxide synthase, phosphorylated-protein kinase B (Akt) and mammalian target of rapamycin activation were assessed using western blotting. H/R treatment decreased the cell viability of H9C2 cells, but activated endogenous Shh signaling. The activation of Shh signaling protected H9C2 myocardial cells from H/R-induced apoptosis and restored cell viability. In the present study, Shh signaling was demonstrated to serve a protective role against H/R by activating the phosphoinositol 3-kinase (PI3K)/Akt pathway and promoting the expression of anti-oxidant enzymes to ameliorate oxidative stress. In summary, Shh signaling attenuated H/R-induced apoptosis through via the PI3K/Akt pathway.

Emerging Roles of Sonic Hedgehog in Adult Neurological Diseases: Neurogenesis and Beyond

Sonic hedgehog (Shh), a member of the hedgehog (Hh) family, was originally recognized as a morphogen possessing critical characters for neural development during embryogenesis. Recently, however, Shh has emerged as an important modulator in adult neural tissues through different mechanisms such as neurogenesis, anti-oxidation, anti-inflammation, and autophagy. Therefore, Shh may potentially have clinical application in neurodegenerative diseases and brain injuries. In this article, we present some examples, including ours, to show different aspects of Shh signaling and how Shh agonists or mimetics are used to alter the neuronal fates in various disease models, both in vitro and in vivo. Other potential mechanisms that are discussed include alteration of mitochondrial function and anti-aging effect; both are critical for age-related neurodegenerative diseases. A thorough understanding of the protective mechanisms elicited by Shh may provide a rationale to design innovative therapeutic regimens for various neurodegenerative diseases.

Coupling of Smoothened to inhibitory G proteins reduces voltage-gated K+ currents in cardiomyocytes and prolongs cardiac action potential duration

SMO (Smoothened), the central transducer of Hedgehog signaling, is coupled to heterotrimeric G_i proteins in many cell types, including cardiomyocytes. In this study, we report that activation of SMO with SHH (Sonic Hedgehog) or a small agonist, purmorphamine, rapidly causes a prolongation of the action potential duration that is sensitive to a SMO inhibitor. In contrast, neither of the SMO agonists prolonged the action potential in cardiomyocytes from transgenic G_iCT/TTA mice, in which G_i signaling is impaired, suggesting that the effect of SMO is mediated by G_i proteins. Investigation of the mechanism underlying the change in action potential kinetics revealed that activation of SMO selectively reduces outward voltage-gated K⁺ repolarizing (Kv) currents in isolated cardiomyocytes and that it induces a down-regulation of membrane levels of Kv4.3 in cardiomyocytes and intact hearts from WT but not from GiCT/TTA mice. Moreover, perfusion of intact hearts with Shh or purmorphamine increased the ventricular repolarization time (QT interval) and induced ventricular arrhythmias. Our data constitute the first report that acute, noncanonical Hh signaling mediated by G_i proteins regulates K⁺ currents density in cardiomyocytes and sensitizes the heart to the development of ventricular arrhythmias.

Plasma proteomic analysis reveals altered protein abundances in cardiovascular disease

BACKGROUND

Cardiovascular disease (CVD) describes the pathological conditions of the heart and blood vessels. Despite the large number of studies on CVD and its etiology, its key modulators remain largely unknown. To this end, we performed a comprehensive proteomic analysis of blood plasma, with the scope to identify disease-associated changes after placing them in the context of existing knowledge, and generate a well characterized dataset for further use in CVD multi-omics integrative analysis.

METHODS

LC-MS/MS was employed to analyze plasma from 32 subjects (19 cases of various CVD phenotypes and 13 controls) in two steps: discovery (13 cases and 8 controls) and test (6 cases and 5 controls) set analysis. Following label-free quantification, the detected proteins were correlated to existing plasma proteomics datasets (plasma proteome database; PPD) and functionally annotated (Cytoscape, Ingenuity Pathway Analysis). Differential expression was defined based on identification confidence (≥ 2 peptides per protein), statistical significance (Mann-Whitney p value ≤ 0.05) and a minimum of twofold change.

RESULTS

Peptides detected in at least 50% of samples per group were considered, resulting in a total of 3796 identified proteins (838 proteins based on ≥ 2 peptides). Pathway annotation confirmed the functional relevance of the findings (representation of complement cascade, fibrin clot formation, platelet degranulation, etc.). Correlation of the relative abundance of the proteins identified in the discovery set with their reported concentrations in the PPD was significant, confirming the validity of the quantification method. The discovery set analysis revealed 100 differentially expressed proteins between cases and controls, 39 of which were verified (≥ twofold change) in the test set. These included proteins already studied in the context of CVD (such as apolipoprotein B, alpha-2-macroglobulin), as well as novel findings (such as low density lipoprotein receptor related protein 2 [LRP2], protein SZT2) for which a mechanism of action is suggested.

CONCLUSIONS

This proteomic study provides a comprehensive dataset to be used for integrative and functional studies in the field. The observed protein changes reflect known CVD-related processes (e.g. lipid uptake, inflammation) but also novel hypotheses for further investigation including a potential pleiotropic role of LPR2 but also links of SZT2 to CVD.

Extracellular vesicles and cardiovascular disease therapy

Cardiovascular disease (CVD) constitutes one of the leading causes of mortality worldwide, therefore representing a major public health concern. Despite recent advances in the treatment of patients with acute myocardial infarction (AMI), such as bypass surgery or percutaneous coronary intervention, pathological cardiac remodeling often predisposes survivors to fatal heart failure. In this context, the proven efficacy of stem cell-regenerative therapies constitutes a promising therapeutic perspective with is nevertheless slow down by safety and ethical concerns. Recent studies have underscored the capacity of stem cell-derived extracellular vesicles (EV) to recapitulate the regenerative properties of their parental cells therefore offering a therapeutic alternative to cell therapy in cardiovascular regenerative medicine. In this article, we review the functional relevance of using stem cell-derived EV as therapeutically agents and detail the identified molecular pathways that they used to exert their effects. We also discuss the advantages of using such an acellular regenerative therapy, in regard with parental stem cells, and address the limitations, which would need to be resolved, before their clinical translation.

Genetic variation associated with cardiovascular risk in autoimmune diseases

Autoimmune diseases have a higher prevalence of cardiovascular events compared to the general population. The objective of this study was to investigate the genetic basis of cardiovascular disease (CVD) risk in autoimmunity. We analyzed genome-wide genotyping data from 6,485 patients from six autoimmune diseases that are associated with a high socio-economic impact. First, for each disease, we tested the association of established CVD risk loci. Second, we analyzed the association of autoimmune disease susceptibility loci with CVD. Finally, to identify genetic patterns associated with CVD risk, we applied the cross-phenotype meta-analysis approach (CPMA) on the genome-wide data. A total of 17 established CVD risk loci were significantly associated with CVD in the autoimmune patient cohorts. From these, four loci were found to have significantly different genetic effects across autoimmune diseases. Six autoimmune susceptibility loci were also found to be associated with CVD risk. Genome-wide CPMA analysis identified 10 genetic clusters strongly associated with CVD risk across all autoimmune diseases. Two of these clusters are highly enriched in pathways previously associated with autoimmune disease etiology (TNFα and IFNγ cytokine pathways). The results of this study support the presence of specific genetic variation associated with the increase of CVD risk observed in autoimmunity.

Extracellular Vesicles in Cardiovascular Theranostics

Extracellular vesicles (EVs) are small bilayer lipid membrane vesicles that can be released by most cell types and detected in most body fluids. EVs exert key functions for intercellular communication via transferring their bioactive cargos to recipient cells or activating signaling pathways in target cells. Increasing evidence has shown the important regulatory effects of EVs in cardiovascular diseases (CVDs). EVs secreted by cardiomyocytes, endothelial cells, fibroblasts, and stem cells play essential roles in pathophysiological processes such as cardiac hypertrophy, cardiomyocyte survival and apoptosis, cardiac fibrosis, and angiogenesis in relation to CVDs. In this review, we will first outline the current knowledge about the physical characteristics, biological contents, and isolation methods of EVs. We will then focus on the functional roles of cardiovascular EVs and their pathophysiological effects in CVDs, as well as summarize the potential of EVs as therapeutic agents and biomarkers for CVDs. Finally, we will discuss the specific application of EVs as a novel drug delivery system and the utility of EVs in the field of regenerative medicine.

Gene delivery nanoparticles to modulate angiogenesis

Angiogenesis is naturally balanced by many pro- and anti-angiogenic factors while an imbalance of these factors leads to aberrant angiogenesis, which is closely associated with many diseases. Gene therapy has become a promising strategy for the treatment of such a disordered state through the introduction of exogenous nucleic acids that express or silence the target agents, thereby engineering neovascularization in both directions. Numerous non-viral gene delivery nanoparticles have been investigated towards this goal, but their clinical translation has been hampered by issues associated with safety, delivery efficiency, and therapeutic effect. This review summarizes key factors targeted for therapeutic angiogenesis and anti-angiogenesis gene therapy, non-viral nanoparticle-mediated approaches to gene delivery, and recent gene therapy applications in pre-clinical and clinical trials for ischemia, tissue regeneration, cancer, and wet age-related macular degeneration. Enhanced nanoparticle design strategies are also proposed to further improve the efficacy of gene delivery nanoparticles to modulate angiogenesis.

In smokers, Sonic hedgehog modulates pulmonary endothelial function through vascular endothelial growth factor

Background

Tobacco-induced pulmonary vascular disease is partly driven by endothelial dysfunction. The Sonic hedgehog (SHH) pathway is involved in vascular physiology. We sought to establish whether the SHH pathway has a role in pulmonary endothelial dysfunction in smokers.

Methods

The ex vivo endothelium-dependent relaxation of pulmonary artery rings in response to acetylcholine (Ach) was compared in 34 current or ex-smokers and 8 never-smokers. The results were expressed as a percentage of the contraction with phenylephrine. We tested the effects of SHH inhibitors (GANT61 and cyclopamine), an SHH activator (SAG) and recombinant VEGF on the Ach-induced relaxation. The level of VEGF protein in the pulmonary artery ring was measured in an ELISA. SHH pathway gene expression was quantified in reverse transcriptase–quantitative polymerase chain reactions.

Results

Ach-induced relaxation was much less intense in smokers than in never-smokers (respectively 24 ± 6% and 50 ± 7% with 10⁻⁴M Ach; p = 0.028). All SHH pathway genes were expressed in pulmonary artery rings from smokers. SHH inhibition by GANT61 reduced Ach-induced relaxation and VEGF gene expression in the pulmonary artery ring. Recombinant VEGF restored the ring’s endothelial function. VEGF gene and protein expression levels in the pulmonary artery rings were positively correlated with the degree of Ach-induced relaxation and negatively correlated with the number of pack-years.

Conclusion

SHH pathway genes and proteins are expressed in pulmonary artery rings from smokers, where they modulate endothelial function through VEGF.

Hh signaling in regeneration of the ischemic heart

Myocardial infarction (MI) is caused by the occlusion of a coronary artery due to underlying atherosclerosis complicated by localized thrombosis. The blockage of blood flow leads to cardiomyocyte (CM) death in the infarcted area. Adult mammalian cardiomyocytes have little capacity to proliferate in response to injury; however, some pathways active during embryogenesis and silent during adult life are recruited in response to tissue injury. One such example is hedgehog (Hh) signaling. Hh is involved in the embryonic development of the heart and coronary vascular system. Pathological conditions including ischemia activate Hh signaling in adult tissues. This review highlights the involvement of Hh signaling in ischemic tissue regeneration with a particular emphasis on heart regeneration and discusses its potential role as a therapeutic agent.

Targeting the hedgehog signaling pathway for cardiac repair and regeneration

The hedgehog (Hh) signaling pathway is involved in the angiogenesis and development of the coronary vasculature in the embryonic heart. Recently, the Hh signal pathway has emerged as an important regulator that can increase cardiomyocyte proliferation, inhibit cardiomyocyte death and apoptosis, recruit endothelial progenitor cell (EPCs) into sites of myocardial ischemia, and direct stem cells to differentiate into cardiac muscle lineage. Experimental studies have tried to target the Hh signaling pathway for cardiac repair and regeneration. The purpose of this review is to discuss the role of the Hh signal pathway in cardiac repair and regeneration as well as the current strategies targeting the Hh signaling pathway and its potential in heart diseases.

Transcription factor ETV1 is essential for rapid conduction in the heart

Rapid impulse propagation in the heart is a defining property of pectinated atrial myocardium (PAM) and the ventricular conduction system (VCS) and is essential for maintaining normal cardiac rhythm and optimal cardiac output. Conduction defects in these tissues produce a disproportionate burden of arrhythmic disease and are major predictors of mortality in heart failure patients. Despite the clinical importance, little is known about the gene regulatory network that dictates the fast conduction phenotype. Here, we have used signal transduction and transcriptional profiling screens to identify a genetic pathway that converges on the NRG1-responsive transcription factor ETV1 as a critical regulator of fast conduction physiology for PAM and VCS cardiomyocytes. Etv1 was highly expressed in murine PAM and VCS cardiomyocytes, where it regulates expression of Nkx2-5, Gja5, and Scn5a, key cardiac genes required for rapid conduction. Mice deficient in Etv1 exhibited marked cardiac conduction defects coupled with developmental abnormalities of the VCS. Loss of Etv1 resulted in a complete disruption of the normal sodium current heterogeneity that exists between atrial, VCS, and ventricular myocytes. Lastly, a phenome-wide association study identified a link between ETV1 and bundle branch block and heart block in humans. Together, these results identify ETV1 as a critical factor in determining fast conduction physiology in the heart.

Hedgehog associated to microparticles inhibits adipocyte differentiation via a non-canonical pathway

Hedgehog (Hh) is a critical regulator of adipogenesis. Extracellular vesicles are natural Hh carriers, as illustrated by activated/apoptotic lymphocytes specifically shedding microparticles (MP) bearing the morphogen (MP(Hh+)). We show that MP(Hh+) inhibit adipocyte differentiation and orientate mesenchymal stem cells towards a pro-osteogenic program. Despite a Smoothened (Smo)-dependency, MP(Hh+) anti-adipogenic effects do not activate a canonical Hh signalling pathway in contrast to those elicited either by the Smo agonist SAG or recombinant Sonic Hedgehog. The Smo agonist GSA-10 recapitulates many of the hallmarks of MP(Hh+) anti-adipogenic effects. The adipogenesis blockade induced by MP(Hh+) and GSA-10 was abolished by the Smo antagonist LDE225. We further elucidate a Smo/Lkb1/Ampk axis as the non-canonical Hh pathway used by MP(Hh+) and GSA-10 to inhibit adipocyte differentiation. Our results highlight for the first time the ability of Hh-enriched MP to signal via a non-canonical pathway opening new perspectives to modulate fat development.

Extracellular vesicles: Pharmacological modulators of the peripheral and central signals governing obesity

Obesity and its metabolic resultant dysfunctions such as insulin resistance, hyperglycemia, dyslipidemia and hypertension, grouped as the "metabolic syndrome", are chronic inflammatory disorders that represent one of the most severe epidemic health problems. The imbalance between energy intake and expenditure, leading to an excess of body fat and an increase of cardiovascular and diabetes risks, is regulated by the interaction between central nervous system (CNS) and peripheral signals in order to regulate behavior and finally, the metabolism of peripheral organs. At present, pharmacological treatment of obesity comprises actions in both CNS and peripheral organs. In the last decades, the extracellular vesicles have emerged as participants in many pathophysiological regulation processes. Whether used as biomarkers, targets or even tools, extracellular vesicles provided some promising effects in the treatment of a large variety of diseases. Extracellular vesicles are released by cells from the plasma membrane (microvesicles) or from multivesicular bodies (exosomes) and contain lipids, proteins and nucleic acids, such as DNA, protein coding, and non-coding RNAs. Owing to their composition, extracellular vesicles can (i) activate receptors at the target cell and then, the subsequent intracellular pathway associated to the specific receptor; (ii) transfer molecules to the target cells and thereby change their phenotype and (iii) be used as shuttle of drugs and, thus, to carry specific molecules towards specific cells. Herein, we review the impact of extracellular vesicles in modulating the central and peripheral signals governing obesity.

Sonic Hedgehog Signaling: Evidence for Its Protective Role in Endotoxin Induced Acute Lung Injury in Mouse Model

Objective

To investigate the protective role of the sonic hedgehog (SHH) signaling associated with a lipopolysaccharide (LPS)-induced acute lung injury (ALI) in a mouse model.

Methods

Male BALB/c mice were randomly divided into four groups: control, LPS, LPS-cyclopamine group and cyclopamine group. ALI was induced by LPS ip injection (5 mg/kg). The sonic hedgehog inhibitor cyclopamine (50 mg/kg) was given to the LPS-cyclopamine group at 30 min after LPS injection as well as normal mice as control. Lung injury was observed histologically in hematoxylin and eosin (HE) stained tissue sections, semi-quantified by lung tissue injury score, and the lung tissue mass alteration was measured by wet to dry weight ratio (W/D). mRNA expression levels of TNF-α, SHH, Patched (PTC) and GLI1 in lung tissue were studied with real time quantitative PCR (RT-PCR), while the protein expression of SHH and GLI1 was determined by western blot analysis.

Results

Lung tissue injury score, thickness of alveolar septa, W/D, and TNF-α mRNA expression levels were significantly higher in the ALI mice than the normal mice (P<0.05). The mRNA expression levels of SHH, PTC, and GLI1 in the ALI mice were significantly higher at 12h and 24h after LPS injection, but not at the 6h time point. Protein production of SHH and GLI1 at 6h, 12h, and 24h in the lungs of ALI mice significantly increased, in a time-dependent manner, compared with that in normal mice. Cyclopamine alone has no effect on pathological changes in normal mice. Intervention with cyclopamine in ALI mice led to a reduction in mRNA levels of SHH, PTC, and GLI1 as well as SHH and GLI1 protein levels; meanwhile, the pathological injury scores of lung tissues, thickness of alveolar septa, W/D, and mRNA expression levels of TNF-α increased compared with mice receiving LPS only.

Conclusion

The SHH signaling pathway was activated in response to LPS-induced ALI, and up-regulation of SHH expression could alleviate lung injury and be involved in the repair of injured lung tissue.

Microparticles from apoptotic RAW 264.7 macrophage cells carry tumour necrosis factor-α functionally active on cardiomyocytes from adult mice

After ischaemic injury and in patients with atherosclerosis, the pool of inflammatory macrophages is enlarged in the heart and in atherosclerotic plaques. Monocyte/macrophage-derived microparticles (MPs) are part of the pathological process of unstable atherosclerotic plaques. The present study focused on effects of MPs, produced by apoptotic murine RAW 264.7 macrophage cell line, in adult murine cardiomyocytes. Flow cytometry and western blot analysis showed that these MPs contained the soluble form of tumour necrosis factor alpha (TNF-α). Cardiomyocyte sarcomere shortening amplitudes and kinetics were reduced within 5 min of exposure to these MPs. Conversely, Ca²⁺ transient amplitude and kinetics were not modified. The contractile effects of MPs were completely prevented after pretreatment with nitric oxide synthase, guanylate cyclase or TNF-α inhibitors as well as blocking TNF-α receptor 1 with neutralizing antibody. Microscopy showed that, after 1 h, MPs were clearly surrounding rod-shaped cardiomyocytes, and after 2 h they were internalized into cardiomyocytes undergoing apoptosis. After 4 h of treatment with MPs, cardiomyocytes expressed increased caspase-3, caspase-8, Bax and cytochrome C. Thus, MPs from apoptotic macrophages induced a negative inotropic effect and slowing of both contraction and relaxation, similar to that observed in the presence of TNF-α. The use of specific inhibitors strongly suggests that TNF-α receptors and the guanylate cyclase/cGMP/PKG pathway were involved in the functional responses to these MPs and that the mitochondrial intrinsic pathway was implicated in their proapoptotic effects. These data suggest that MPs issued from activated macrophages carrying TNF-α could contribute to propagation of inflammatory signals leading to myocardial infarction.

Role of Trimetazidine in Ischemic Preconditioning in Patients With Symptomatic Coronary Artery Disease

Ischemic preconditioning (IP) is a powerful cardioprotective cellular mechanism that has been related to the "warm-up phenomenon" or "walk-through" angina, and has been documented through the use of sequential exercise tests (ETs). It is known that several drugs, for example, cromokalim, pinacidil, adenosine, and nicorandil, can interfere with the cellular pathways of IP. The purpose of this article is to report the effect of the anti-ischemic agent trimetazidine (TMZ) on IP in symptomatic coronary artery disease (CAD) patients.We conducted a prospective study evaluating IP by the analysis of ischemic parameters in 2 sequential ETs. In phase I, without TMZ, patients underwent ET1 and ET2 with a 30-minute interval between them. In phase II, after 1 week of TMZ 35 mg twice daily, all patients underwent 2 consecutive ETs (ET3 and ET4). IP was considered present when the time to 1.0-mm segment ST on electrocardiogram deviation (T-1.0 mm) and rate pressure product (RPP) were greater in the second of 2 tests. The improvement in T-1.0 mm and RPP were compared in the 2 phases: without TMZ and after 1-week TMZ to assess the action of such drug in myocardial protective mechanisms. ETs were analyzed by 2 independent cardiologists.From 135 CAD patients screened, 96 met inclusion criteria and 62 completed the study protocol. Forty patients manifested IP by demonstrating an improvement in T-1.0 mm in ET2 compared with ET1, without the use of any drugs (phase I). In phase II, after 1-week TMZ, 26 patients (65%) did not show any incremental result in ischemic parameters in ET4 compared with ET3. Furthermore, of these patients, 8 (20%) had IP blockage.In this study, TMZ did not add any benefit to IP in patients with stable symptomatic CAD.