Cardiomyocytes derived small extracellular vesicles plays an important role in heart development

Introduction

Neonatal rats have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. Cardiac maturation lays the foundation for postnatal heart development and disease, yet little is known about the contributions of the microenvironment to cardiomyocyte maturation.

Extracellular vesicles (EV) are bilayer-membrane nanoparticles released by all cell types, carrying proteins, lipids, and nucleic acids, which reflect the activation state of parental cells. Secreted small extracellular vesicles (sEV), prominently figure among extracellular signals that regulate cell function.

Purpose

We aim to determine whether cardiomyocyte (CM) derived sEV carried miRNA that has a role in heart development with specific regards to cardiomyocyte maturation.

Methods

sEV were isolated from rat cardiomyocyte at day 0 and 7 after birth by serial ultracentrifugation. sEV were characterized by NTA and analyzed by Western blot for the presence of classical EV markers (TSG101, Syntenin-1). The role of sEV in cardiomyocyte proliferation was assessed by analysis of EdU incorporation on neoantal rat CM treated with sEV_p0 or sEV_p7. miRNA content on sEV was assessed using a rat-miRNome MicroRNA Profiling Kit and the identified miRNA's targets confirmed by RealTime-PCR and Western Blot.

Results

NTA and Western Blot analysis confirmed the presence of sEV in both the extracellular vesicles preparation. sEV_p0 showed to be able to sligtly increase EdU incorporation in treated cardiomyocyte (1.15-Fold) while sEV_p7 significantly inihibit CM proliferation (0.78-Fold) toghether with a change in cardiomyocyte citoscheletal architecture. Data from miRNome analysis showed in sEV_p7 a significan increase in miRNA with cyclines as tagets. Downregulation of Cdk1; Cdk4; Cdk2; CcnB1 and CcnD1 was confirmed on CM trated with sEV_p7 compared to Ctrl. Downregulation of CCND1 was aslo confrmed at the protein level by Western Blot analysis.

Conclusions

These preliminary resultes showed an important role in heart develompent of cardiomyocyte derived-sEV. A deeper investigation of the pathaway activated by sEV may have a potential interest for the identification of possible regulators for stimulating heart regeneration.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Fondazione Leonardo, Lugano, Switzerland

Human amniotic fluid stem cell-extracellular vesicles as paracrine candidates to rejuvenate cardiomyocyte renewal

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): University of Genova

Background

Reactivation of cardiomyocyte renewal represents a milestone for cardiac regeneration. While broadly active in the early neonatal mammalian myocardium, such mechanism is lost soon after birth, with transition to defective repair. We previously showed that human amniotic fluid stem cells (hAFS) possess cardioprotective and cardioactive paracrine potential in a preclinical adult mouse model of myocardial infarction (MI)1, by sustaining cardiomyocyte cell cycle re-entry up to DNA duplication.

Purpose

Here we analyse whether hAFS secretome formulations, namely hAFS-conditioned medium (hAFS-CM) over extracellular vesicles (hAFS-EVs) separated from that, can enhance cardiomyocyte renewal in vitro and in vivo.

Methods

hAFS were obtained by leftover samples of prenatal screening amniocentesis and primed under 1% O2 preconditioning to enrich hAFS-CM and hAFS-EVs with cardioactive factors. hAFS-EVs were concentrated from hAFS-CM by serial ultracentrifugation. hAFS-EVs were profiled by electron microscopy, nanoparticle tracking analysis, proteomics and RNA sequencing (RNAseq). Neonatal mouse ventricular cardiomyocytes (mNVCM) were enzymatically isolated from R26pFUCCI2 mice with fluorescent tagging of cell-cycle by nuclear signal (G1-phase by Cdt1-mCherry; S-G2-M-phases by Geminin-mVenus1)2. mNVCM were stimulated by hAFS-CM or hAFS-EVs to identify the most promising formulation for further analysis in a R26pFUCCI2 4-day-old MI mouse model via intra-peritoneal delivery, according to principles of laboratory animal care and in compliance with authorization from the Italian Ministry of Health.

Results

hAFS-EVs sustained R26pFUCCI2 mNVCM transition from S- to M-phase by 2.1-fold (*p<0.05) in vitro, while triggering cytokinesis by 4.5-fold (*p<0.05) increase by Aurora B kinase expression at midbodies. Treated mNVCM showed disorganized expression of cardiac α-actinin, suggesting cytoskeletal re-arrangements prior to cell renewal, with significant down-regulation (0.6-fold, ****p<0.0001) of Cofilin-2 (CFL-2) an actin cytoskeleton regulator antagonizing cardiomyocyte proliferation3. RNAseq on hAFS-EVs revealed some of the mostly enriched microRNAs (miRNAs) targeting CFL-2 (miR-93-5p; miR-152-3p; miR-200b-3p; miR-429; miR-199a-3p; miR-20a-5p; miR-425-5p), while proteomics reported enrichment of a secreted form of Agrin, an important mediator for neonatal heart regeneration4. hAFS-EVs increased cardiomyocyte S- to M phase transition by 1.8-fold (*p<0.05) in the mouse neonatal left ventricle 3 days post-MI.

Conclusions

Our current findings suggest that EVs secreted by developmentally juvenile hAFS may be endowed with relevant potential to support cardiomyocyte renewal for future paracrine therapy in regenerative medicine with putative molecular candidate(s) of action in their cargo content including Agrin and non-coding miRNAs.

Cardiomyocytes (CM) derived small Extracellular Vesicles (sEV) plays an important role in heart development

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Schweizerische Herzstiftung - FF21017

Fondazione Leonardo

Introduction

Neonatal rats have the capacity to regenerate their hearts in response to injury, but this potential is lost after the first week of life. Cardiac maturation lays the foundation for postnatal heart development and disease, yet little is known about the contributions of the microenvironment to cardiomyocyte maturation.

Extracellular vesicles (EV) are bilayer-membrane nanoparticles released by all cell types, carrying proteins, lipids, and nucleic acids, which reflect the activation state of parental cells. Secreted small extracellular vesicles (sEV), prominently figure among extracellular signals that regulate cell function.

Purpose

We aim to determine whether cardiomyocyte (CM) derived sEV carried miRNA that has a role in heart development with specific regards to cardiomyocyte maturation.

Methods

sEV were isolated from rat cardiomyocyte at day 0 and 7 after birth by serial ultracentrifugation. sEV were characterized by NTA and analyzed by Western blot for the presence of classical EV markers (TSG101, Syntenin-1). The role of sEV in cardiomyocyte proliferation was assesed by analysis of EdU incorporation on neoantal rat CM treated with sEV_p0 or sEV_p7. miRNA content on sEV was assesed using a rat-miRNome MicroRNA Profiling Kit and the identified miRNA's targets confirmed by RealTime-PCR and Western Blot.

Results

NTA and Western Blot analysis confirmed the presence of sEV in both the extracellular vesicles preparation. sEV_p0 showed to be able to sligtly increase EdU incorporation in treated cardiomyocyte (1.15-Fold) while sEV_p7 significantly inihibit CM proliferation (0.78-Fold) toghether with a change in cardiomyocyte citoscheletal architecture. Data from miRNome analysis showed in sEV_p7 a significan increase in miRNA with cyclines as tagets. Downregulation of Cdk1 ; Cdk4 ; Cdk2 ; CcnB1 and CcnD1 was confirmed on CM trated with sEV_p7 compared to Ctrl. Downregulation of CCND1 was aslo confrmed at the protein level by Western Blot analysis.

Conclusions

These preliminary resultes showed an important role in heart develompent of cardiomyocyte derived-sEV. A deeper investigation of the pathaway activated by sEV may have a potential interest for the identification of possible regulators for stimulating heart regeneration.

Sgk1 enhances RANBP1 transcript levels and decreases taxol sensitivity in RKO colon carcinoma cells

The serum- and glucocorticoid-regulated kinase (Sgk1) is essential for hormonal regulation of epithelial sodium channel-mediated sodium transport and is involved in the transduction of growth factor-dependent cell survival and proliferation signals. Growing evidence now points to Sgk1 as a key element in the development and/or progression of human cancer. To gain insight into the mechanisms through which Sgk1 regulates cell proliferation, we adopted a proteomic approach to identify up- or downregulated proteins after Sgk1-specific RNA silencing. Among several proteins, the abundance of which was found to be up- or downregulated upon Sgk1 silencing, we focused our attention of RAN-binding protein 1 (RANBP1), a major effector of the GTPase RAN. We report that Sgk1-dependent regulation of RANBP1 has functional consequences on both mitotic microtubule activity and taxol sensitivity of cancer cells.

Functional analysis of R75Q mutation in the gene coding for Connexin 26 identified in a family with nonsyndromic hearing loss

Mutations in the gene (GJB2) coding for Connexin 26 (Cx26) are responsible for genetic forms of sensorineural hearing loss. This article describes a family characterized by congenital profound hearing loss, inherited in an autosomal dominant fashion and associated to a R75Q substitution in Cx26. Cell transfection and fluorescence imaging, dye transfer experiments and dual patch clamp recording showed that the mutant completely prevents the formation of functional channels despite assembling into junctional plaques, in communication incompetent HeLa cells. The disease is not associated with palmar and plantar keratosis in any of the family members, suggesting that R75Q substitution is not sufficient for the development of the complete syndromic phenotype. The association of palmar and plantar keratosis with profound hearing loss may be dependent on genetic background, requiring a functional interaction between the mutated Cx26 and other epidermally expressed connexins.

Emx2 promotes symmetric cell divisions and a multipotential fate in precursors from the cerebral cortex

Distinct sets of precursor cells generate the mammalian cerebral cortex. During neurogenesis most precursors are specified to generate a single cell type and only few are multipotent. The cell-intrinsic molecular determinants of these distinct lineages are not known. Here we describe that retroviral transduction of the transcription factor Emx2 in precursors from the cerebral cortex results in a significant increase of large clones that are generated mostly by symmetric cell divisions and contain multiple cell types, comprising neurons and glial cells. Thus, Emx2 is the first cell-intrinsic determinant able to instruct CNS precursors towards a multipotential fate. To evaluate the role of endogenous Emx2 in cortical precursors, we examined cell division in Emx2-/- mice. These analyses further supported the role of endogenous Emx2 in the regulation of symmetric cell divisions in the developing cortex.

In vivo PC3 overexpression by retroviral vector affects cell differentiation of rat cortical precursors

The PC3 gene is a marker of dividing neuroepithelial (NE) cells. We transduced single cortical precursors of the ventricular zone (VZ) with a PC3-carrying retroviral vector at E16 stage, and analysed the effects of transgene expression on their progeny in 3-week-old animals. Unlike control-transduced cells, all viable PC3-transduced cells remained close to the ventricle and displayed a round-shaped, undifferentiated morphology.

Prevention of pericardial adhesions with N-O carboxymethylchitosan in the rabbit model

The presence of mediastinal adhesions significantly increases the morbidity and mortality of reoperative cardiac surgical procedures. Previous investigations have reported on the therapeutic utility of topical hydrogels in reducing the formation of postsurgical adhesions. The goal of the present study is to evaluate the ability of N-O carboxymethylchitosan (a glycosaminoglycan hydrogel derivative) to reduce the formation ofpostsurgical pericardial adhesions in a large-animal model. Sixteen adult New Zealand white rabbits were randomly assigned to one of two treatment groups. Group 1 subjects (n = 8) had N-O carboxymethylchitosan directly applied to the heart and retrosternal surfaces after sternotomy was performed, while subjects in group 2 (n = 8) had saline applied to these areas. After a period of 14 days the animals were sacrificed under anesthesia, and independent observers, blinded to treatment, graded the formation of pericardial adhesions. The severity of adhesion formation was significantly less in the group treated with N-O carboxymethylchitosan (p < .01). This study demonstrates that N-O carboxymethylchitosan markedly decreases the formation of poststernotomy adhesions in a large-animal model without untoward cardiac side effects. This hydrogel derivative may prove to be of great therapeutic value when used prophylactically in the setting of cardiac surgery.

Isolation of radial glial cells by fluorescent-activated cell sorting reveals a neuronal lineage

The developing central nervous system of vertebrates contains an abundant cell type designated radial glial cells. These cells are known as guiding cables for migrating neurons, while their role as precursor cells is less clear. Since radial glial cells express a variety of astroglial characteristics and differentiate as astrocytes after completing their guidance function, they have been considered as part of the glial lineage. Using fluorescence-activated cell sorting, we show here that radial glial cells also are neuronal precursors and only later, after neurogenesis, do they shift towards an exclusive generation of astrocytes. These results thus demonstrate a novel function for radial glial cells, namely their ability to generate two major cell types found in the nervous system, neurons and astrocytes.

PC3 overexpression affects the pattern of cell division of rat cortical precursors

The PC3 gene is transiently expressed during neurogenesis in precursor cells of the telencephalic ventricular/subventricular zone, and is rapidly downregulated before cell migration and differentiation. It is thought to have a role in controlling cell proliferation, but its precise function is not known. Here we present evidence that PC3, when overexpressed in vitro by retroviral-mediated gene transfer, acts by interfering with the normal pattern of cell division. Firstly, we report evidence that PC3 overexpression reduces the rate of cell proliferation in both NIH 3T3 cells and embryonic precursor cells from the rat cerebral cortex. Secondly, when studying the pattern of BrdU dilution in clones of cortical precursors, we observe that clones transduced with PC3 show an asymmetric pattern of BrdU dilution more frequently than clones transduced with a control vector. We discuss the hypothesis that the higher number of PC3 transduced clones showing an asymmetric pattern of BrdU dilution may be due to an increase in asymmetric cell divisions.

Characterization of a cloned xenopus laevis serotonin 5-HT1A receptor expressed in the NIH-3T3 cell line

In a previous work we isolated a Xenopus 5-HT1A receptor gene and now report the characterization of this receptor. The HindIII-XbaI fragment of this gene was cloned into the pcDNA I NEO vector and stably transfected into eukaryotic cells (NIH-3T3). To determine the specific 5-HT1A receptor binding, [3H]8-OH-DPAT was used as radioligand. The selective 5-HT1A receptor agonist bound only a single class of saturable high-affinity binding sites with pharmacological characteristics similar to those of the mammalian 5-HT1A receptor. The effects of X5-HT1A receptor activation on cell growth were also investigated in stably transfected NIH-3T3 cells. The 5-HT1A agonist 8-OH-DPAT was found to increase DNA synthesis and accelerated cell growth.

Deletion polymorphism of angiotensin-converting enzyme gene and left ventricular hypertrophy in southern Italian patients

OBJECTIVES

This study sought to evaluate the possible association of polymorphism of the angiotensin-converting enzyme (ACE) gene with blood pressure and left ventricular mass index (LVMI).

BACKGROUND

The renin-angiotensin system seems to be involved in the pathogenesis of essential hypertension. Moreover, recent epidemiologic observations demonstrate that many subjects with left ventricular hypertrophy have normal blood pressure levels, suggesting that factors other than hemodynamic overload may contribute to the hypertrophy.

METHODS

The study included 140 untreated hypertensive outpatients who underwent ambulatory blood pressure monitoring, echocardiographic evaluation and analysis for insertion (I)/ deletion (D) polymorphism in intron 16 of the ACE gene by polymerase chain reaction. Blood pressure was measured at 24 h, and LVMI was calculated by the Devereux formula, in each patient.

RESULTS

Left ventricular mass index values (mean +/- SD) were 137 +/- 28 g/m2 in patients with the DD genotype, 125 +/- 27 g/m2 in those with the ID genotype and 115 +/- 27 g/m2 in those with II genotype. The frequencies of the DD, ID and II genotypes were 45.71% (n = 64), 46.42% (n = 65) and 7.85% (n = 11), respectively, and were in Hardy-Weinberg equilibrium. The strongest association between left ventricular mass and DD genotype in our cohort appeared to be an independent cardiovascular risk factor (DD vs. ID: odds ratio [OR] 2.497, 95% confidence interval [CI] interval 1.158 to 5.412, p < 0.05; DD vs. II: OR 6.577, 95% CI 1.169 to 28.580, p < 0.02).

CONCLUSIONS

Our data show that the LVMI was significantly enhanced in patients with the DD genotype.

The effects of hemodilution with polyethylene glycol bovine hemoglobin (PEG-Hb) in a conscious porcine model

BACKGROUND

Severe hemodilution in large mammals has been used rigorously for the safety and efficacy testing of hemoglobin-based red blood cell substitutes. The effects of hemodilution with polyethylene glycol-modified bovine hemoglobin (PEG-Hb) were investigated in an unanesthetized porcine model.

METHODS

Immature Yorkshire cross barrow pigs were subjected to exchange transfusion with PEG-Hb (n = 6) or dextran 70 (n = 4) until an 80% reduction in hematocrit was achieved.

RESULTS

All six (100%) PEG-Hb-infused pigs and only one (25%) dextran 70 control pig survived the resultant reduction in erythrocytes. Heart rates and mean arterial pressure were not significantly affected by PEG-Hb infusion. Pigs infused with PEG-Hb maintained normal levels of blood pH, PO2, and PCO2 while dextran 70 controls showed low PvO2, PaCO2, and the development of acidosis. Histological evaluation revealed that the surviving dextran 70 control animal exhibited possible anoxia-induced hepatic centrilobular necrosis. PEG-Hb-treated pigs demonstrated the presence of renal tubular cell cytoplasmic vacuoles and vacuolated macrophages in spleens.

CONCLUSIONS

The results indicate that PEG-Hb effectively supports life close to lethal levels of anemia.

[Effort hernia of the diaphragm: apropos of a case]

The so-called stress diaphragmatic hernias are very unusual in the group of post-traumatic hernias. The Authors report a case and consider clinical, anatomical as well as pathophysiological aspects of the disease. Diagnostic procedures and therapeutic approach are also stressed.