Recent Research Trends in Neuroinflammatory and Neurodegenerative Disorders

Neuroinflammatory and neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD), traumatic brain injury (TBI) and Amyotrophic lateral sclerosis (ALS) are chronic major health disorders. The exact mechanism of the neuroimmune dysfunctions of these disease pathogeneses is currently not clearly understood. These disorders show dysregulated neuroimmune and inflammatory responses, including activation of neurons, glial cells, and neurovascular unit damage associated with excessive release of proinflammatory cytokines, chemokines, neurotoxic mediators, and infiltration of peripheral immune cells into the brain, as well as entry of inflammatory mediators through damaged neurovascular endothelial cells, blood-brain barrier and tight junction proteins. Activation of glial cells and immune cells leads to the release of many inflammatory and neurotoxic molecules that cause neuroinflammation and neurodegeneration. Gulf War Illness (GWI) and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are chronic disorders that are also associated with neuroimmune dysfunctions. Currently, there are no effective disease-modifying therapeutic options available for these diseases. Human induced pluripotent stem cell (iPSC)-derived neurons, astrocytes, microglia, endothelial cells and pericytes are currently used for many disease models for drug discovery. This review highlights certain recent trends in neuroinflammatory responses and iPSC-derived brain cell applications in neuroinflammatory disorders.

scaRNA20 promotes pseudouridylatory modification of small nuclear snRNA U12 and improves cardiomyogenesis

Non-coding RNAs, particularly small Cajal-body associated RNAs (scaRNAs), play a significant role in spliceosomal RNA modifications. While their involvement in ischemic myocardium regeneration is known, their role in cardiac development is unexplored. We investigated scaRNA20's role in iPSC differentiation into cardiomyocytes (iCMCs) via overexpression and knockdown assays. We measured scaRNA20-OE-iCMCs and scaRNA20-KD-iCMCs contractility using Particle Image Velocimetry (PIV), comparing them to control iCMCs. We explored scaRNA20's impact on alternative splicing via pseudouridylation (Ψ) of snRNA U12, analyzing its functional consequences in cardiac differentiation. scaRNA20-OE-iPSC differentiation increased beating colonies, upregulated cardiac-specific genes, activated TP53 and STAT3, and preserved contractility under hypoxia. Conversely, scaRNA20-KD-iCMCs exhibited poor differentiation and contractility. STAT3 inhibition in scaRNA20-OE-iPSCs hindered cardiac differentiation. RNA immunoprecipitation revealed increased Ψ at the 28th uridine of U12 RNA in scaRNA20-OE iCMCs. U12-KD iCMCs had reduced cardiac differentiation, which improved upon U12 RNA introduction. In summary, scaRNA20-OE in iPSCs enhances cardiomyogenesis, preserves iCMC function under hypoxia, and may have implications for ischemic myocardium regeneration.

Mesenchymal Stem Cell-Derived Long Noncoding RNAs in Cardiac Injury and Repair

Cardiac injury, such as myocardial infarction and heart failure, remains a significant global health burden. The limited regenerative capacity of the adult heart poses a challenge for restoring its function after injury. Mesenchymal stem cells (MSCs) have emerged as promising candidates for cardiac regeneration due to their ability to differentiate into various cell types and secrete bioactive molecules. In recent years, attention has been given to noncoding RNAs derived from MSCs, particularly long noncoding RNAs (lncRNAs), and their potential role in cardiac injury and repair. LncRNAs are RNA molecules that do not encode proteins but play critical roles in gene regulation and cellular responses including cardiac repair and regeneration. This review focused on MSC-derived lncRNAs and their implications in cardiac regeneration, including their effects on cardiac function, myocardial remodeling, cardiomyocyte injury, and angiogenesis. Understanding the molecular mechanisms of MSC-derived lncRNAs in cardiac injury and repair may contribute to the development of novel therapeutic strategies for treating cardiovascular diseases. However, further research is needed to fully elucidate the potential of MSC-derived lncRNAs and address the challenges in this field.

Differential Expression of Non-Coding RNAs in Stem Cell Development and Therapeutics of Bone Disorders

Stem cells' self-renewal and multi-lineage differentiation are regulated by a complex network consisting of signaling factors, chromatin regulators, transcription factors, and non-coding RNAs (ncRNAs). Diverse role of ncRNAs in stem cell development and maintenance of bone homeostasis have been discovered recently. The ncRNAs, such as long non-coding RNAs, micro RNAs, circular RNAs, small interfering RNA, Piwi-interacting RNAs, etc., are not translated into proteins but act as essential epigenetic regulators in stem cells' self-renewal and differentiation. Different signaling pathways are monitored efficiently by the differential expression of ncRNAs, which function as regulatory elements in determining the fate of stem cells. In addition, several species of ncRNAs could serve as potential molecular biomarkers in early diagnosis of bone diseases, including osteoporosis, osteoarthritis, and bone cancers, ultimately leading to the development of new therapeutic strategies. This review aims to explore the specific roles of ncRNAs and their effective molecular mechanisms in the growth and development of stem cells, and in the regulation of osteoblast and osteoclast activities. Furthermore, we focus on and explore the association of altered ncRNA expression with stem cells and bone turnover.

Therapeutic potentials of stem cell-derived exosomes in cardiovascular diseases

Exosomes are extracellular vesicles released by many cell types with varying compositions. Major bioactive factors present in exosomes are protein, lipid, mRNA, and miRNA. Exosomes are fundamental regulators of cellular trafficking and signaling in both physiological and pathological conditions. Various conditions such as oxidative stress, endoplasmic reticulum stress, ribosomal stress, and thermal stress alter the concentration of exosomal mRNA, and miRNA, lipids, and proteins. Stem cell-derived exosomes have been shown to regulate a variety of stresses, either inhibiting or promoting cell balance. Stem cell-derived exosomes direct the crosstalk between various cell types which helps recovery by transferring information in proteins, lipids, and so on. This is one of the reasons why exosomes are used as biomarkers for a multitude of disease conditions. This review highlights the bioengineering of fabricated exosomal cargoes. It includes the manipulation and delivery of specific exosomal cargoes such as noncoding RNAs, recombinant proteins, immune modulators, therapeutic drugs, and small molecules. Such therapeutic approaches may precisely deliver the therapeutic drugs at the target site in the management of various disease conditions. Importantly, we have focused on the therapeutic applications of stem cell-derived exosomes in cardiovascular disease conditions such as myocardial infarction, ischemic heart disease, cardiomyopathy, heart failure, sepsis, and cardiac fibrosis. Generally, two approaches are being followed by researchers for exosomal bioengineering. This literature review will shed light on the role of stem cell-derived exosomes in stress balance and provides a new avenue for the treatment of cardiovascular diseases.

Abstract P2111: Hutchinson Gilford Progeria Patient-specific Induced Cardiomyocyte Model Carrying Lamin A Gene Variant C.1824 C > T

Background: Hutchinson-Gilford progeria (HGP) is a rare genetic disorder in which children age rapidly. They suffer from atherosclerosis, cardiovascular diseases, and strokes. The LMNA variant c.1824C>T accounts for ~90% of HGP cases. This variant causes an abnormal Lamin A protein called progerin. The detailed molecular mechanisms of Lamin A in the heart remain elusive due to the lack of appropriate in vitro models.

Hypothesis: We hypothesize that HGP patient’s induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMCs) will provide a model platform to study the cardio-pathologic mechanisms associated with progeria.

Methods and Results: We performed in silico analysis of LMNA variant c.1824C>T to determine its effects on Lamin A structure and stability. For validation , skin fibroblasts (SFs) from a de-identified HGP patient (hPGP1, proband) and parents were obtained from the Progeria Foundation. Through Sanger sequencing (Fig 1A) and restriction fragment length polymorphism, with enzyme EciI , targeting Lamin A, we characterized hPGP1-SFs as heterozygous mutants for variant c.1824 C>T. Then, we reprogrammed the three SFs into iPSCs (Fig 1B) using a safe mRNA-based reprogramming method , and differentiated them into iCMCs, which gained beating on day 7. We found that hPGP1-iCMCs (Fig 1C) had an irregular contractile function by Particle Image Velocimetry Analysis and decreased cardiac-specific gene and protein expressions by qRT-PCR and Western Blot.

Conclusions: We successfully generated iCMCs from a progeria patient carrying LMNA variant c.1824C>T. These iCMCs were found to be functionally and structurally defective when compared to normal iCMCs. Our in vitro model will help elucidate the role of Lamin A and the cardio-pathologic mechanisms associated with progeria.

Abstract P1038: Exosomal RNAs And Proteins From Non-invasively Derived Human Induced Mesenchymal Stem Cells Protect Cardiomyocytes From Death

Background: Current stem cells therapy for ischemic cardiomyopathy is effective only about 2-4% in improving cardiac function. In search of novel therapy, we have developed a safe mRNA-based reprogramming of non-invasively derived human urinary epithelial cells into induced pluripotent stem cells (iPSC), and subsequently differentiated them into mesenchymal stem cells (iMSC). We examined therapeutic potential of iMSC in comparison with adult umbilical cord mesenchymal stem cells (MSC).

Hypothesis: Autologous iMSC and their exosomes possess an enhanced cardioprotective characteristics compared to MSC.

Methods and Results: The generated iMSC and their exosomes (ExoQuick reagent) offered an enhanced protection of human iPSC-derived cardiomyocytes (iCMC) from injuries of (i) angiotensin-II (Ang, 10 μM for 24 h) and (ii) 6 hrs of 1% hypoxia and 24 hrs of reoxygenation, in comparison with their MSC controls. The cardiomyocyte protection was studied through measurement of mitochondrial membrane potential (JC1 dye), intracellular reactive oxygen species (CM-H2DCFDA), in situ cell death by apoptosis, and qRT-PCR expression of survival and proinflammatory genes (BCL2, BAD, TNFA and IL6). Treatment with iMSC-derived exosomes alone enhanced the expression of NRF2, a major regulator of cytoprotective genes in protecting Ang-challenged iCMC. The specific role of iMSC exosomal RNAs and proteins in mediating cardioprotection against Ang-induced injury was identified through in situ cell death assay using the exosomes treated with either RNase A (0.5 μg/μl for 20 min at 37 0 C) or proteinase K (0.05 μg/μl for 10 min at 37 0 C) (Fig.1) . Exosomal noncoding RNA analysis by qRT-PCR revealed the presence of inflammation-associated small nucleolar RNAs such as SNORD32A, SNORD33, SNORD34 and SNORD35A. The transfer of exosomal RNAs into the host cardiac cells was augmented in presence of Ang, identified using 0.5 mM ethynyl uridine-labelled exosomes and detected using Click-iT RNA imaging reagents. All experiments were carried out in triplicates. In vivo studies are in progress.

Conclusion: In comparison with adult MSC, non-invasively derived autologous iMSC and their exosomes elicit enhanced cardioprotection and may provide an alternative source of cells or cell-free therapy for treating ischemic cardiomyopathy.

Efficient and Safe Method of Generating Induced Pluripotent Stem Cells from Human Skin Fibroblasts and Subsequent Differentiation into Functional Cardiomyocytes

Studies have shown that human-induced pluripotent stem cells (iPSCs) derived cardiomyocytes (iCMCs) would provide a limitless source of cells for regenerative therapy and drug discoveries. Similar to embryonic stem cells, iPSCs have the capability to differentiate into mature functional iCMCs. The objective of our study is to develop an animal-free and viral-free approach by using a highly efficient transfection method that utilizes a critical combination of DNAs and mRNAs of pluripotent genes to generate iPSCs from adult human skin fibroblasts (SF). Subsequently differentiated them into functional cardiomyocytes. We obtained 4% of SFs into iPSCs at Passage 0, which shows significantly higher efficiency of reprogramming when compared to the use of either DNA alone or mRNAs alone. These iPSCs cultured under cardiac culture conditions are capable of differentiating into iCMCs. Furthermore, >88% of iCMCs are positive for either cardiac troponin T (TNNT2) or GATA binding protein 4 (GATA4). The iCMCs produced from SFs have been used in our laboratory to demonstrate their in vitro and in vivo functional potentials. In this study, we present step-by-step procedures for the generation of iPSCs from SFs and further differentiate them toward functional iCMCs.

In-Silico and In-Vitro Analysis of Human SOS1 Protein Causing Noonan Syndrome - A Novel Approach to Explore the Molecular Pathways

Aims

Perform in-silico analysis of human SOS1 mutations to elucidate their pathogenic role in Noonan syndrome (NS).

Background

NS is an autosomal dominant genetic disorder caused by single nucleotide mutation in PTPN11, SOS1, RAF1, and KRAS genes. NS is thought to affect approximately 1 in 1000. NS patients suffer different pathogenic effects depending on the mutations they carry. Analysis of the mutations would be a promising predictor in identifying the pathogenic effect of NS.

Methods

We performed computational analysis of the SOS1 gene to identify the pathogenic nonsynonymous single nucleotide polymorphisms (nsSNPs) th a t cause NS. SOS1 variants were retrieved from the SNP database (dbSNP) and analyzed by in-silico tools I-Mutant, iPTREESTAB, and MutPred to elucidate their structural and functional characteristics.

Results

We found that 11 nsSNPs of SOS1 that were linked to NS. 3D modeling of the wild-type and the 11 nsSNPs of SOS1 showed that SOS1 interacts with cardiac proteins GATA4, TNNT2, and ACTN2. We also found that GRB2 and HRAS act as intermediate molecules between SOS1 and cardiac proteins. Our in-silico analysis findings were further validated using induced cardiomyocytes (iCMCs) derived from NS patients carrying SOS1 gene variant c.1654A>G (NSiCMCs) and compared to control human skin fibroblast-derived iCMCs (C-iCMCs). Our in vitro data confirmed that the SOS1, GRB2 and HRAS gene expressions as well as the activated ERK protein, were significantly decreased in NS-iCMCs when compared to C-iCMCs.

Conclusion

This is the first in-silico and in vitro study demonstrating that 11 nsSNPs of SOS1 play deleterious pathogenic roles in causing NS.

Understanding diabetes-induced cardiomyopathy from the perspective of renin angiotensin aldosterone system

Experimental and clinical evidence suggests that diabetic subjects are predisposed to a distinct cardiovascular dysfunction, known as diabetic cardiomyopathy (DCM), which could be an autonomous disease independent of concomitant micro and macrovascular disorders. DCM is one of the prominent causes of global morbidity and mortality and is on a rising trend with the increase in the prevalence of diabetes mellitus (DM). DCM is characterized by an early left ventricle diastolic dysfunction associated with the slow progression of cardiomyocyte hypertrophy leading to heart failure, which still has no effective therapy. Although the well-known "Renin Angiotensin Aldosterone System (RAAS)" inhibition is considered a gold-standard treatment in heart failure, its role in DCM is still unclear. At the cellular level of DCM, RAAS induces various secondary mechanisms, adding complications to poor prognosis and treatment of DCM. This review highlights the importance of RAAS signaling and its major secondary mechanisms involving inflammation, oxidative stress, mitochondrial dysfunction, and autophagy, their role in establishing DCM. In addition, studies lacking in the specific area of DCM are also highlighted. Therefore, understanding the complex role of RAAS in DCM may lead to the identification of better prognosis and therapeutic strategies in treating DCM.

Modern approaches on stem cells and scaffolding technology for osteogenic differentiation and regeneration

The process of bone repair has always been a natural mystery. Although bones do repair themselves, supplemental treatment is required for the initiation of the self-regeneration process. Predominantly, surgical procedures are employed for bone regeneration. Recently, cell-based therapy for bone regeneration has proven to be more effective than traditional methods, as it eliminates the immune risk and painful surgeries. In clinical trials, various stem cells, especially mesenchymal stem cells, have shown to be more efficient for the treatment of several bone-related diseases, such as non-union fracture, osteogenesis imperfecta, osteosarcoma, and osteoporosis. Furthermore, the stem cells grown in a suitable three-dimensional scaffold support were found to be more efficient for osteogenesis. It has been shown that the three-dimensional bioscaffolds support and simulate an in vivo environment, which helps in differentiation of stem cells into bone cells. Bone regeneration in patients with bone disorders can be improved through modification of stem cells with several osteogenic factors or using stem cells as carriers for osteogenic factors. In this review, we focused on the various types of stem cells and scaffolds that are being used for bone regeneration. In addition, the molecular mechanisms of various transcription factors, signaling pathways that support bone regeneration and the senescence of the stem cells, which limits bone regeneration, have been discussed.

Abstract P470: Disrupted HRAS/GRB2 Signaling In Induced-cardiomyocytes Derived From Patients With Noonan Syndrome Carrying SOS1 Gene Mutation

Background: Noonan syndrome (NS), a dominant autosomal genetic disorder that prevents normal development, and exhibits cardiac defects, which is estimated to appear in 50% to 90% of patients. Son of sevenless homolog 1 (SOS1) gene mutation has been identified as a major gene causing NS and attributes to the development of cardiomyopathy and congenital heart defects. SOS1 is a guanine nucleotide exchange factor for RAS and is known to interact with growth factor receptor-bound protein 2 (GRB2). Recently, we have generated induced pluripotent stem cells (iPSCs)-derived cardiomyocytes (iCMCs) from cardiac fibroblasts obtained from a NS patient carrying SOS1 gene variant 1654A>G.

Hypothesis: Since NS is known to have aberrant RAS-MAPK signaling, we hypothesize that iCMCs derived from NS patient (NS-iCMCs) may have atypical RAS signaling leading to the development of cardiomyopathy.

Methods and Results: We have compared the normal skin fibroblast-derived iPSCs (N-iPSCs) and N-iCMCs with NS patient-derived induced NS-iPSCs and NS-iCMCs. Our qRT-PCR results showed that the mRNA expressions of signaling molecules HRAS, GRB2 and SOS1 were significantly decreased in NS-iCMCs compared with N-iCMCs (Figure A), and further confirmed through the protein expression by Western immunoblotting (Figure B). These results were in association with a significantly decreased mRNA and protein expressions of cardiac transcription factor GATA4, and structural proteins alpha sarcomeric actinin-2 (ACTN2), cardiac troponin T (TNNT2) and tropomyosin alpha-1 (TPM1) in NS-iCMCs compared with N-iCMCs. Further studies are underway to explore the difference in the guanine nucleotide exchange factor (GEF) activity and ERK activation between NS-iCMCs and N-iCMCs.

Conclusion: Our current findings clearly indicate that the SOS1-associated signaling molecules HRAS and GRB2 were disrupted in NS-iCMCs, which may result in the development of cardiomyopathy in NS patients.

Comparative analysis of human induced pluripotent stem cell-derived mesenchymal stem cells and umbilical cord mesenchymal stem cells

Generation of induced pluripotent stem cells (iPSCs) and their differentiation into mesenchymal stem/stromal cells (iMSCs) have created exciting source of cells for autologous therapy. In this study, we have compared the therapeutic potential of iMSCs generated from urinary epithelial (UE) cells with the available umbilical cord MSCs (UC‐MSCs). For this, adult UE cells were treated with the mRNA of pluripotent genes (OCT4, NANOG, SOX2, KLF4, MYC and LIN28) and a cocktail of miRNAs under specific culture conditions for generating iPSCs. Our non‐viral and mRNA‐based treatment regimen demonstrated a high reprogramming efficiency to about 30% at passage 0. These UE‐iPSCs were successfully differentiated further into ectoderm, endoderm and mesoderm lineage of cells. Moreover, these UE‐iPSCs were subsequently differentiated into iMSCs and were compared with the UC‐MSCs. These iMSCs were capable of differentiating into osteocytes, chondrocytes and adipocytes. Our qRT‐PCR and Western blot data showed that the CD73, CD90 and CD105 gene transcripts and proteins were highly expressed in iMSCs and UC‐MSCs but not in other cells. The comparative qRT‐PCR data showed that the iMSCs maintained their MSC characteristics without any chromosomal abnormalities even at later passages (P15), during which the UC‐MSCs started losing their MSC characteristics. Importantly, the wound‐healing property demonstrated through migration assay was superior in iMSCs when compared to the UC‐MSCs. In this study, we have demonstrated an excellent non‐invasive and pain‐free method of obtaining iMSCs for regenerative therapy. These homogeneous autologous highly proliferative iMSCs may provide an alternative source of cells to UC‐MSCs for treating various diseases.

Noonan syndrome patient-specific induced cardiomyocyte model carrying SOS1 gene variant c.1654A>G

Noonan syndrome (NS) is a dominant autosomal genetic disorder, associated with mutations in several genes that exhibit multisystem abnormal development including cardiac defects. NS associated with the Son of Sevenless homolog 1 (SOS1) gene mutation attributes to the development of cardiomyopathy and congenital heart defects. Since the treatment option for NS is very limited, an in vitro disease model with SOS1 gene mutation would be beneficial for exploring therapeutic possibilities for NS. We reprogrammed cardiac fibroblasts obtained from a NS patient and normal control skin fibroblasts (C-SF) into induced pluripotent stem cells (iPSCs). We identified NS-iPSCs carry a heterozygous single nucleotide variation in the SOS1 gene at the c.1654A > G. Furthermore, the control and NS-iPSCs were differentiated into induced cardiomyocytes (iCMCs), and the electron microscopic analysis showed that the sarcomeres of the NS-iCMCs were highly disorganized. FACS analysis showed that 47.5% of the NS-iCMCs co-expressed GATA4 and cardiac troponin T proteins, and the mRNA expression levels of many cardiac related genes, studied by qRT-PCR array, were significantly reduced when compared to the control C-iCMCs. We report for the first time that NS-iPSCs carry a single nucleotide variation in the SOS1 gene at the c.1654A>G were showing significantly reduced cardiac genes and proteins expression as well as structurally and functionally compromised when compared to C-iCMCs. These iPSCs and iCMCs can be used as a modeling platform to unravel the pathologic mechanisms and also the development of novel drug for the cardiomyopathy in patients with NS.

Role of Human Mesenchymal Stem Cells in Regenerative Therapy

Mesenchymal stem cells (MSCs) are multipotent cells which can proliferate and replace dead cells in the body. MSCs also secrete immunomodulatory molecules, creating a regenerative microenvironment that has an excellent potential for tissue regeneration. MSCs can be easily isolated and grown in vitro for various applications. For the past two decades, MSCs have been used in research, and many assays and tests have been developed proving that MSCs are an excellent cell source for therapy. This review focusses on quality control parameters required for applications of MSCs including colony formation, surface markers, differentiation potentials, and telomere length. Further, the specific mechanisms of action of MSCs under various conditions such as trans-differentiation, cell fusion, mitochondrial transfer, and secretion of extracellular vesicles are discussed. This review aims to underline the applications and benefits of MSCs in regenerative medicine and tissue engineering.

Abstract 515: Non-invasive Method of Generating Human Induced-mesenchymal Stem Cells Derived From Urinary Epithelial Cells for Regenerative Therapy

Introduction: Mesenchymal stem cells (MSCs) are multipotent adult stem cells having an extensive proliferation capacity in vitro and in vivo. These MSCs can differentiate into various mesoderm-type cells such as osteoblasts, cardiomyocytes, etc. A subpopulation of urinary epithelial cells (UECs) have been identified in urine samples, is considered a promising cell resource for generating autologous induced-pluripotent stem cells (iPSCs).

Hypothesis: We hypothesize that the production of high quality, autologous, induced-MSCs (iMSCs) with high replicative potential suitable for the regenerative therapy, using an easy, and the most non-invasive method of isolation, from human UECs.

Methods and Results: Human urine was collected and centrifuged to obtain the UECs, which were characterized by the expression of CK19 and ZO1. These UECs were reprogrammed to iPSCs using a cocktail of mRNAs (OCT4, KLF4, SOX2, c-MYC, Nanog and Lin28) along with Lipofectamine for 11 days in culture. These iPSCs were characterized by the expression of the pluripotent markers such as OCT4, SOX2 and SSEA4. The iPSCs were subsequently differentiated into iMSCs using the mesenchymal specific medium for 21 days. iMSCs were harvested at the end of 21 days, and they were characterized by the high levels of mRNA and protein expressions of mesenchymal specific markers such as CD73, CD90 and CD105 (Fig. 1A). FACS analysis showed that more than 93% of the cells were positive for the markers of MSCs (Fig. 1B) . Moreover, the obtained iMSCs have high proliferation capacity compared with the adult stem cells.

Conclusions: We have developed an easy, non-invasive method for obtaining autologous, non-immunogenic and highly-proliferating iMSCs suitable for various regenerative therapies including cardiac diseases, from urinary epithelial cells.

Abstract 502: Inhibition of Histone Deacetylase 6 Protects Human Induced Pluripotent Stem Cells-derived Cardiomyocytes Through Inhibition of Autophagy

Introduction: Autophagy is known to play an important role in mediating cardiac hypertrophy. However, the mechanism is poorly understood. Since the protein histone deacetylase 6 (HDAC6) contributes to cardiac dysfunction in response to angiotensin II (AngII) signaling, we have examined the role of HDAC6 inhibitor tubastatin A (TBA) in AngII-induced remodeling in human induced pluripotent stem cells-derived cardiomyocytes (iCMCs).

Hypothesis: We hypothesize that the inhibition of HDAC6 protects iCMCs from AngII-induced cardiac hypertrophy through inhibition of autophagy.

Methods and Results: We have generated and characterized induced pluripotent stem cells from human adult skin fibroblasts and subsequently differentiated them into iCMCs. Treatment with 10 μM angiotensin II for 24 hrs increased the HDAC6 activity and lead to hypertrophy in iCMCs. The AngII-induced hypertrophy, and the excessive contractility in iCMCs were reversed by the inhibition of HDAC6 with TBA (1 μM for 24 hours). The number of LC3-positive iCMCs, and the mRNA and the protein expression of autophagic genes Beclin-1, LC3, and p62 were increased by the presence of AngII, and the anti-autophagic gene Bcl2 was decreased by AngII. The inhibition of HDAC6 with TBA reversed the AngII-mediated changes in the autophagic genes expressions in iCMCs. Autophagic vacuoles were identified with monodansylcadaverine (MDC, green) and lysosomes with LysoTracker (red) (Fig. 1A) . The number of autophagolysosomes were increased by AngII, and this was decreased with TBA in iCMCs (Fig. 1B) .

Conclusions: Our report indicates for the first time that the AngII-induced cardiac hypertrophy-mediated autophagy is effectively inhibited by the suppression of HDAC6 in human iCMCs.

Abstract 489: Identification And In-silico Analysis Of Pathogenic Non-synonymous Snps Of Human Sos1 Protein In Noonan Syndrome

Introduction: Noonan syndrome is a genetic disorder (autosomal dominant) characterized by short stature, congenital heart disease, bleeding problems, developmental delays, and skeletal malformation. It is mainly caused by a single nucleotide alteration in four genes PTPN11, SOS1, RAF1, and KRAS . In this study, we computationally analyzed the SOS1 gene to identify the pathogenic non-synonymous single nucleotide polymorphisms (nsSNPs), which is known to cause Noonan syndrome.

Hypothesis: We hypothesize that in-silico analysis of human SOS1 mutations in Noonan syndrome would be a promising predictor to study the post-translational modifications.

Methods and Results: The variant information of SOS1 was collected from the dbSNP database and the literature review on Noonan syndrome. They were further analyzed by in-silico tools such as I-Mutant, iPTREE-STAB, and MutPred for their structural and functional properties. We found that 11 nsSNPs are more pathogenic for Noonan syndrome. The 3D comparative protein of 11 nsSNPs with its wild-type SOS1 was modeled by using I-Tasser and validated via ERRAT and RAMPAGE. The protein-protein interactions of SOS1, GATA4, TNNT2, and ACTN2 were analyzed using STRING, which showed that HRAS was intermediate between SOS1 and ACTN2 (Fig. 1) .

Conclusion: This is the first in-silico study of the SOS1 variant with Noonan syndrome. We proposed that this 11 nsSNPs are the most pathogenic variant of SOS1 , which helps to screen the Noonan patient. Furthermore, our results are promising to study the gain/loss of post-translational modification (PTM) by mutation in cardiac genes and helps to explore the novel molecular pathways.$graphic_{DB5B0E7D-4DA6-4569-A16F-E05B2C9C4D2F}$$

Analgesic, Anti-Inflammatory, Cytotoxic Activity Screening and UPLC-PDA-ESI-MS Metabolites Determination of Bioactive Fractions of Kleinia pendula

Kleinia pendula (Forssk.) DC. is a prostrate or pendent dark green succulent herb found in the southwestern mountain regions of Saudi Arabia. The literature survey of the plant reveals a lack of phytochemical and pharmacological studies, although traditional uses have been noted. The objective of the present work was to assess the in vivo analgesic and anti-inflammatory activities, as well as, the in vitro cytotoxic potential of the fractions of Kleinia pendula, and correlate these activities to the plant metabolites. The methanolic extract of Kleinia pendula was subjected to fractionation with n-hexane, ethyl acetate, chloroform, n-butanol, and water. The fractions were screened for their analgesic and anti-inflammatory activities, as well as cytotoxic activity against breast, liver, and colon cancer cell lines. The n-hexane and chloroform fractions of Kleinia pendula showed significant cytotoxic activity against all three cancer cell lines tested. The ethyl acetate and chloroform fractions showed significant analgesic and anti-inflammatory activities. The metabolites in these three active fractions were determined using UPLC-PDA-ESI-MS. Thus, the analgesic and anti-inflammatory activities of the plant were attributed to its phenolic acids (caffeoylquinic acid derivatives, protocatechuic, and chlorogenic acids). While fatty acids and triterpenoids such as (tormentic acid) in the hexane fraction are responsible for the cytotoxic activity; thus, these fractions of Kleinia pendula may be a novel source for the development of new plant-based analgesic, anti-inflammatory, and anticancer drugs.

Non-viral reprogramming and induced pluripotent stem cells for cardiovascular therapy

Despite significant effort devoted to developing new treatments and procedures, cardiac disease is still one of the leading causes of death in the world. The loss of myocytes due to ischemic injury remains a major therapeutic challenge. However, cell-based therapy to repair the injured heart has shown significant promise in basic and translation research and in clinical trials. Embryonic stem cells have been successfully used to improve cardiac outcomes. Unfortunately, treatment with these cells is complicated by ethical and legal issues. Recent progress in developing induced pluripotent stem cells (iPSCs) using non-viral vectors has made it possible to derive cardiomyocytes for therapy. This review will focus on these non-integration-based approaches for reprogramming and their therapeutic advantages for cardiovascular medicine.

Adult Stem Cells for Regenerative Therapy

Cell therapy has been identified as an effective method to regenerate damaged tissue. Adult stem cells, also known as somatic stem cells or resident stem cells, are a rare population of undifferentiated cells, located within a differentiated organ, in a specialized structure, called a niche, which maintains the microenvironments that regulate the growth and development of adult stem cells. The adult stem cells are self-renewing, clonogenic, and multipotent in nature, and their main role is to maintain the tissue homeostasis. They can be activated to proliferate and differentiate into the required type of cells, upon the loss of cells or injury to the tissue. Adult stem cells have been identified in many tissues including blood, intestine, skin, muscle, brain, and heart. Extensive preclinical and clinical studies have demonstrated the structural and functional regeneration capabilities of these adult stem cells, such as bone marrow-derived mononuclear cells, hematopoietic stem cells, mesenchymal stromal/stem cells, resident adult stem cells, induced pluripotent stem cells, and umbilical cord stem cells. In this review, we focus on the human therapies, utilizing adult stem cells for their regenerative capabilities in the treatment of cardiac, brain, pancreatic, and eye disorders.

Steroidal Saponin Diosgenin from Dioscorea bulbifera Protects Cardiac Cells from Hypoxia-reoxygenation Injury Through Modulation of Pro-survival and Pro-death Molecules

Background:

Diosgenin, a steroidal saponin from plants, exhibits many biological potentials. Herein, the cardioprotective role of diosgenin is studied.

Materials and Methods:

The effect of diosgenin, isolated from Dioscorea bulbifera, was studied on hypoxia-reoxygenation (HR) in H9c2 cardiomyoblast cells. The amount of diosgenin in the plant extract was analyzed by high-performance thin layer chromatography using a solvent system comprising of chloroform:methanol:acetic acid:formic acid (13:4.5:1.5:1). Cardioprotection was checked by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Further, the release of lactate dehydrogenase, an enzyme released during cell death was checked. The proteins responsible for cell death (Bax) and cell survival (Bcl-2, hemeoxygenase-1 and Akt) were analyzed using Western blot to check the cardioprotective role of diosgenin.

Conclusion:

Supplementation of diosgenin mitigates HR injury, thereby exhibiting cardioprotective potential.

SUMMARY

The cardioprotective effect of Diosgenin was evidenced from the improved cell survival after hypoxia-reoxygenation injury demonstrated through MTT cell survival assay.

The release of lactate dehydrogenase, an enzyme released during cell death was decreased by Diosgenin.

Diosgenin upregulated the pro-survival molecules like B-cell lymphoma 2 (Bcl-2), heme oxygenase-1 and the phosphorylation of ATK (at serine 473); and at the same time pro-.death molecules like Bax was downregulated.

Thus, Diosgenin as a plant based steroidal saponin is confirmed to mitigate ischemic reperfusion injury.

Abstract 126: Functional Properties of Cardiac Stem Cell Niches in the Young and Old Heart

Cardiac stem cells (CSCs) are clustered in interstitial structures, in which cardiomyocytes and fibroblasts act as supporting cells. However, the effects of the niche microenvironment on the functional properties of CSCs are largely unknown and whether young and senescent myocytes affect differently CSC fate remains to be determined. To address this issue, cardiac niches were examined in young and old Fischer 344 rats. Clusters composed of two or more lineage negative CSCs were included in the analysis. Unexpectedly, from 4 to 28 months of age, the number of CSCs per niche increased nearly 2-fold. This expansion of the CSC pool took place despite the increase in the fraction of dying CSCs with age. Apoptosis of CSCs was restricted to cells expressing the senescence-associated protein p16 INK4a . However, the fraction of CSCs positive for p16 INK4a increased significantly, documenting that the process of clearance of senescent CSCs was inefficient in the old myocardium. The fraction of p16 INK4a -positive CSCs undergoing apoptosis decreased 3.5-fold with age, resulting in accumulation of senescent cells within the niche. These observations indicate that the pool of functionally competent CSCs able to contribute to myocyte turnover decreased with age. In an attempt to compensate for the higher myocyte loss occurring in aged hearts, p16 INK4a -negative CSCs proliferated 4-fold more in old than in young rats, experiencing progressive telomeric shortening. To define whether the fate of CSCs was dictated by the properties of the neighboring myocytes in the senescent heart, myocytes and CSCs were co-cultured for 3 days. With respect to CSCs plated alone, old myocytes enhanced 2.2-fold BrdU incorporation in co-cultured CSCs. This effect was less apparent with young myocytes. No significant differences in CSC apoptosis were seen. Comparable results were obtained when CSCs and myocytes were plated in Transwell systems. Importantly, old myocytes released more IGF-1 than young myocytes; blockade of IGF-1 receptor in CSCs attenuated significantly the positive impact of myocytes on CSC replication. Collectively, our findings indicate that the rate of accumulation of old CSCs is greater than the rate of their death leading to the formation of senescent niches and organ aging.

Abstract 256: Dysfunctional Cardiac Stem Cell Niches Condition the Aging of the Heart

The objective of this study was to determine whether aging of the heart is characterized by alterations in the cellular composition of cardiac niches and defective cardiomyogenesis. By employing a morphometric approach in which the three-dimensional structure of each niche was evaluated, we examined 40 and 20 cardiac niches in young and old Fischer 344 rats, respectively. Although a niche can include a single stem cell, clusters composed of three or more cardiac stem cells (CSCs) and early lineage committed cells (LCCs) were included in the analysis. LCCs expressed the stem cell antigen c-kit in combination with the marker of cardiac commitment GATA4. The average volume of the niches did not vary with age. Surprisingly, the number of lineage-negative CSCs increased from 4 to 28 months. Young niches contained 6 CSCs while old niches showed 10 CSCs. However, the fraction of CSCs positive for the senescence-associated marker p16 INK4a increased 14-fold with age, from 6% to 85%. Corresponding values for LCCs were 8% and 82%. Apoptosis of CSCs-LCCs increased with age and was restricted to p16 INK4a -positive-cells. However, the fraction of senescent CSCs-LCCs undergoing apoptosis decreased 3.5-fold with age: apoptosis was detected in 7% and 2% of p16 INK4a positive CSCs-LCCs of young and old animals, respectively resulting in the accumulation of senescent cells.Freshly isolated CSCs proliferated in response to growth stimuli but this effect was attenuated in old cells. This finding was consistent with the decreased expression of the insulin-like growth factor receptor 1 (IGF-1R) in senescent CSCs. Collectively, the accumulation of senescent CSCs and the poor response of p16 INK4a- negative CSCs to growth stimuli determined the formation of dysfunctional niches. Abnormal niche turnover led to the generation of rapidly aging cardiomyocytes. In conclusion, the cellular composition of the niches varies with age. The decrease in the number of functionally-competent CSCs-LCCs together with the accumulation of senescent CSCs-LCCs limits the ability of CSC niches to repopulate the senescent ventricular myocardium.

Abstract 19: Myocyte Turnover in the Aging Human Heart

The controversy on the growth reserve of the adult human heart has not been resolved and the extent of myocyte renewal reported by different groups varies significantly. Additionally, myocyte regeneration has been claimed to decrease with aging, although cell death is markedly enhanced in the old myocardium. Thus, the effects of age and gender on the magnitude of myocyte turnover were determined. Myocyte replication, senescence and apoptosis were measured in normal female and male human hearts collected from patients 19 to 104 years of age who died from causes other than cardiovascular diseases. Myocardial aging was characterized by a time-dependent increase in the generation of amplifying cardiomyocytes in women and men. Levels of Ki67 and phospho-H3 were comparable in the young female and male heart but differed later in life. As a function of age, the pool of amplifying myocytes was 2-fold higher in women than men, pointing to enhanced myocyte renewal in the female heart. The frequency of p16 INK4a -positive myocytes was higher in men than in women. From 19 to 104 years of age, the time-dependent increase in senescent myocytes was 0.68% per year in women and 0.89% per year in men; the 31% higher rate of accumulation of old myocytes in the aging male heart was significant. Myocyte apoptosis occurred only in p16 INK4a -positive cells and was consistently higher in men than in women at all age intervals. However, the increase in myocyte apoptosis with age did not differ with gender. Based on these parameters, we measured the average age of cardiomyocytes, their age distribution, turnover rate and time to acquire the senescent phenotype to define the biology of myocardial aging as a function of lifespan. In the female heart, myocyte turnover occurs at a rate of 10%, 15% and 40% per year at 20, 60 and 100 years of age, respectively. Corresponding values in the male heart are 7%, 12% and 32% per year, documenting that cardiomyogenesis involves a large and progressively increasing number of parenchymal cells with aging. In conclusion, the human heart is a highly dynamic organ in which progressive myocyte loss is at least in part counteracted by enhanced myocyte renewal. Myocyte regeneration in the physiologically aging heart takes place at previously unexpected levels in both women and men.

Regeneration of infarcted myocardium with resveratrol-modified cardiac stem cells

The major problem in stem cell therapy includes viability and engraftment efficacy of stem cells after transplantation. Indeed, the vast majority of host-transfused cells do not survive beyond 24–72 hrs. To increase the survival and engraftment of implanted cardiac stem cells in the host, we developed a technique of treating these cells with resveratrol, and tested it in a rat model of left anterior descending (LAD) occlusion. Multi-potent clonogenic cardiac stem cells isolated from rat heart and stably transfected with EGFP were pre-treated with 2.5 μM resveratrol for 60 min. Rats were anaesthetized, hearts opened and the LAD occluded to induce heart attack. One week later, the cardiac reduced environment was confirmed in resveratrol treated rat hearts by the enhanced expression of nuclear factor-E2-related factor-2 (Nrf2) and redox effector factor-1 (Ref-1). M-mode echocardiography after stem cell therapy, showed improvement in cardiac function (left ventricular ejection fraction, fractional shortening and cardiac output) in both, the treated and control group after 7 days, but only resveratrol-modified stem cell group revealed improvement in cardiac function at the end of 1, 2 and 4 months time. The improvement of cardiac function was accompanied by enhanced stem cell survival and engraftment as demonstrated by the expression of cell proliferation marker Ki67 and differentiation of stem cells towards the regeneration of the myocardium as demonstrated by the expression of EGFP up to 4 months after LAD occlusion in the resveratrol-treated stem cell group. Expression of stromal cell-derived factor and myosin conclusively demonstrated homing of stem cells in the infarcted myocardium, its regeneration leading to improvement of cardiac function.

Olmesartan medoxomil treatment potently improves cardiac myosin-induced dilated cardiomyopathy via the modulation of ACE-2 and ANG 1-7 mas receptor

Angiotensin converting enzyme-2 (ACE-2) is a monocarboxypeptidase that metabolises angiotensin (ANG)-II into angiotensin 1-7 (ANG 1-7), thereby functioning as a negative regulator of the renin-angiotensin system. We investigated whether treatment with ANG-II type 1 receptor blocker, olmesartan medoxomil is associated with the attenuation of cardiac myosin-induced dilated cardiomyopathy (DCM) through recently established new axis of ACE-2/ANG 1-7 mas receptor. DCM was elicited in Lewis rats by immunisation with cardiac myosin, and 28 days after immunisation, the surviving Lewis rats were divided into two groups and treated with either olmesartan medoxomil (10 mg/kg/day) or vehicle. Myocardial protein and mRNA levels of ACE-2, ANG 1-7 mas receptor were upregulated in the olmesartan-treated group compared with those of vehicle-treated DCM rats. In contrast, Olmesartan treatment effectively suppressed the myocardial protein and mRNA expressions of inflammatory markers in comparison to the vehicle-treated DCM rats. Olmesartan treatment significantly reduced fibrosis, hypertrophy and their marker molecules (OPN, CTGF, ANP and GATA-4, respectively), as well as matrix metalloproteinases compared with those of vehicle-treated DCM rats. Enhanced myocardial protein levels of phospho-p38 MAPK, phospho-JNK and phospho MAPKAPK-2 in the vehicle-treated DCM rats were prevented by olmesartan treatment. In addition, olmesartan treatment significantly lowered the protein expressions (Nitrotyrosine, p47phox and p67phox) and superoxide radical production compared with those of vehicle-treated DCM rats. Our present study might serve as a new therapeutic target of DCM in cardiovascular diseases and cardiac myosin-induced DCM via the modulation of ACE-2/ANG 1-7 mas receptor axis in rats with DCM after myosin-immunisation.

Olmesartan attenuates the development of heart failure after experimental autoimmune myocarditis in rats through the modulation of ANG 1-7 mas receptor

Angiotensin-converting enzyme 2 (ACE-2) is a membrane-associated carboxy-peptidase catalyzes the conversion of the vasoconstrictor angiotensin (ANG)-II to the vasodilatory peptide ANG 1-7. In view of the expanding axis of the renin angiotensin system, we have investigated the cardioprotective effects of olmesartan (10mg/kg/day) in experimental autoimmune myocarditis. Olmesartan treatment effectively suppressed the myocardial protein expressions of inflammatory markers in comparison to the vehicle-treated rats. However, the protein and mRNA levels of ACE-2 and ANG 1-7, and its receptor Mas were upregulated in olmesartan treated group compared to vehicle-treated rats. Olmesartan medoxomil treatment significantly decreased the expression levels of phospho-p38 mitogen-activated protein kinase (MAPK), phospho-JNK, phospho-ERK and phospho-(MAPK) activated protein kinase-2 than with those of vehicle-treated rats. Moreover, vehicle-treated rats were shown to be up-regulated protein expressions of NADPH oxidase subunits (p47phox, p67phox and Nox-4), myocardial apoptotic markers and endoplasmic reticulum stress markers in comparison to those of normal and all these effects are expectedly down-regulated by an olmesartan. In addition, attenuated protein levels of phosphatidylinositol-3-kinase (PI3K) and phospho-Akt in the vehicle-treated EAM rats were prevented by olmesartan treatment. Our results suggest that beneficial effects of olmesartan treatment was more effective therapy in combating the inflammation, oxidative stress, apoptosis and signaling pathways associated with heart failure at least in part via the modulation of ANG 1-7 mas receptor.

Role of differential signaling pathways and oxidative stress in diabetic cardiomyopathy

Diabetes mellitus increases the risk of heart failure independently of underlying coronary artery disease, and many believe that diabetes leads to cardiomyopathy. The underlying pathogenesis is partially understood. Several factors may contribute to the development of cardiac dysfunction in the absence of coronary artery disease in diabetes mellitus. There is growing evidence that excess generation of highly reactive free radicals, largely due to hyperglycemia, causes oxidative stress, which further exacerbates the development and progression of diabetes and its complications. Hyperglycemia-induced oxidative stress is a major risk factor for the development of micro-vascular pathogenesis in the diabetic myocardium, which results in myocardial cell death, hypertrophy, fibrosis, abnormalities of calcium homeostasis and endothelial dysfunction. Diabetes-mediated biochemical changes show cross-interaction and complex interplay culminating in the activation of several intracellular signaling molecules. Diabetic cardiomyopathy is characterized by morphologic and structural changes in the myocardium and coronary vasculature mediated by the activation of various signaling pathways. This review focuses on the oxidative stress and signaling pathways in the pathogenesis of the cardiovascular complications of diabetes, which underlie the development and progression of diabetic cardiomyopathy.

Cardioprotective effects of telmisartan against heart failure in rats induced by experimental autoimmune myocarditis through the modulation of angiotensin-converting enzyme-2/angiotensin 1-7/mas receptor axis

Angiotensin-converting enzyme-2 (ACE-2) is a homolog of ACE that preferentially forms angiotensin-(ANG)-1-7 from angiotensin II (ANG II). We investigated the cardioprotective effects of telmisartan, a well-known angiotensin receptor blockers (ARBs) against experimental autoimmune myocarditis (EAM). EAM was induced in Lewis rats by immunization with porcine cardiac myosin. The rats were divided into two groups and treated with telmisartan (10 mg/kg/day) or vehicle for 21 days. Myocardial functional parameters were significantly improved by treatment with telmisartan compared with vehicle-treated rats. Telmisartan lowered myocardial protein expressions of NADPH oxidase subunits 3-nitrotyrosine, p47phox, p67 phox, Nox-4 and superoxide production significantly than vehicle-treated rats. In contrast myocardial protein levels of ACE-2, ANG 1-7 mas receptor were upregulated in the telmisartan treated group compared with those of vehicle-treated rats. The myocardial protein expression levels of tumor necrosis factor receptor (TNFR)-associated factor (TRAF)-2, C/EBP homologous protein (CHOP) and glucose-regulated protein (GRP) 78 were decreased in the telmisartan treated rats compared with those of vehicle-treated rats. In addition, telmisartan treatment significantly decreased the protein expression levels of phospho-p38 mitogen-activated protein kinase (MAPK), phospho-JNK, phospho-ERK and phospho (MAPK) activated protein kinase-2 than with those of vehicle-treated rats. Moreover, telmisartan significantly decreased the production of proinflammatory cytokines, myocardial apoptotic markers and caspase-3 positive cells compared with those of vehicle-treated rats. Therefore, we suggest that telmisartan was beneficial protection against heart failure in rats, at least in part by suppressing inflammation, oxidative stress, ER stress as well as signaling pathways through the modulation of ACE2/ANG1-7/Mas receptor axis.

Resveratrol in cardiovascular health and disease

Resveratrol, initially used for cancer therapy, has shown beneficial effects against most degenerative and cardiovascular diseases from atherosclerosis, hypertension, ischemia/reperfusion, and heart failure to diabetes, obesity, and aging. The cardioprotective effects of resveratrol are associated with its preconditioning-like action potentiated by its adaptive response. During preconditioning, small doses of resveratrol can exert an adaptive stress response, forcing the expression of cardioprotective genes and proteins such as heat shock and antioxidant proteins. Similarly, resveratrol can induce autophagy, another form of stress adaptation for degrading damaged or long-lived proteins, as a first line of protection against oxidative stress. Resveratrol's interaction with multiple molecular targets of diverse intracellular pathways (e.g., action on sirtuins and FoxOs through multiple transcription factors and protein targets) intertwines with those of the autophagic pathway to give support in the modified redox environment after stem cell therapy, which leads to prolonged survival of cells. The successful application of resveratrol in therapy is based upon its hormetic action similar to any toxin: exerting beneficial effects at lower doses and cytotoxic effects at higher doses.

Red wine antioxidant resveratrol-modified cardiac stem cells regenerate infarcted myocardium

To study the efficiency of maintaining the reduced tissue environment via pre-treatment with natural antioxidant resveratrol in stem cell therapy, we pre-treated male Sprague-Dawley rats with resveratrol (2.5 mg/kg/day gavaged for 2 weeks). After occlusion of the left anterior descending coronary artery (LAD), adult cardiac stem cells stably expressing EGFP were injected into the border zone of the myocardium. One week after the LAD occlusion, the cardiac reduced environment was confirmed in resveratrol-treated rat hearts by the enhanced expression of nuclear factor-E2-related factor-2 (Nrf2) and redox effector factor-1 (Ref-1). In concert, cardiac functional parameters (left ventricular ejection fraction and fractional shortening) were significantly improved. The improvement of cardiac function was accompanied by the enhanced stem cell survival and proliferation as demonstrated by the expression of cell proliferation marker Ki67 and differentiation of stem cells towards the regeneration of the myocardium as demonstrated by the enhanced expression of EGFP 28 days after LAD occlusion in the resveratrol-treated hearts. Our results demonstrate that resveratrol maintained a reduced tissue environment by overexpressing Nrf2 and Ref-1 in rats resulting in an enhancement of the cardiac regeneration of the adult cardiac stem cells as demonstrated by increased cell survival and differentiation leading to cardiac function.

Olmesartan, an AT1 antagonist, attenuates oxidative stress, endoplasmic reticulum stress and cardiac inflammatory mediators in rats with heart failure induced by experimental autoimmune myocarditis

Studies have demonstrated that angiotensin II has been involved in immune and inflammatory responses which might contribute to the pathogenesis of immune-mediated diseases. Recent evidence suggests that oxidative stress may play a role in myocarditis. Here, we investigated whether olmesartan, an AT(1)R antagonist protects against experimental autoimmune myocarditis (EAM) by suppression of oxidative stress, endoplasmic reticulum (ER) stress and inflammatory cytokines. EAM was induced in Lewis rats by immunization with porcine cardiac myosin, were divided into two groups and treated with either olmesartan (10 mg/kg/day) or vehicle for a period of 21 days. Myocardial functional parameters measured by hemodynamic and echocardiographic analyses were significantly improved by the treatment with olmesartan compared with those of vehicle-treated rats. Treatment with olmesartan attenuated the myocardial mRNA expressions of proinflammatory cytokines, [Interleukin (IL)-1β, monocyte chemoattractant protein-1, tumor necrosis factor-α and interferon-γ)] and the protein expression of tumor necrosis factor-α compared with that of vehicle-treated rats. Myocardial protein expressions of AT(1)R, NADPH oxidase subunits (p47phox, p67phox, gp91phox) and the expression of markers of oxidative stress (3-nitrotyrosine and 4-hydroxy-2-nonenal), and the cardiac apoptosis were also significantly decreased by the treatment with olmesartan compared with those of vehicle-treated rats. Furthermore, olmesartan treatment down-regulated the myocardial expressions of glucose regulated protein-78, growth arrest and DNA damage-inducible gene, caspase-12, phospho-p38 mitogen-activated protein kinase (MAPK) and phospho-JNK. These findings suggest that olmesartan protects against EAM in rats, at least in part via suppression of oxidative stress, ER stress and inflammatory cytokines.

Co-ordinated autophagy with resveratrol and γ-tocotrienol confers synergetic cardioprotection

This study compared two dietary phytochemicals, grape-derived resveratrol and palm oil-derived γ-tocotrienol, either alone or in combination, on the contribution of autophagy in cardioprotection during ischaemia and reperfusion. Sprague-Dawley rats weighing between 250 and 300 g were randomly assigned to one of the following groups: vehicle, ischaemia/reperfusion (I/R), resveratrol + I/R, γ-tocotrienol + I/R, resveratrol +γ-tocotrienol + I/R. For resveratrol treatments, the rats were gavaged with resveratrol (2.5 mg/kg) for 15 days while for γ-tocotrienol experiments the rats were gavaged with γ-tocotrienol (0.3 mg/kg) for 30 days. For the combined resveratrol +γ-tocotrienol experiments, the rats were gavaged with γ-tocotrienol for 15 days, and then gavaging continued with resveratrol along with γ-tocotrienol for a further period of 15 days. After 30 days, isolated perfused hearts were subjected to 30 min. of global ischaemia followed by 2 hrs of reperfusion. Our results showed for the first time that at least in part, the cardioprotection (evidenced from the ventricular performance, myocardial infarct size and cardiomyocyte apoptosis) with resveratrol and γ-toctrienol was achieved by their abilities to induce autophagy. Most importantly, resveratrol and γ-tocotrienol acted synergistically providing greater degree of cardioprotection simultaneously generating greater amount of survival signal through the activation of Akt-Bcl-2 survival pathway. Autophagy was accompanied by the activation of Beclin and LC3-II as well as mTOR signalling, which were inhibited by either 3-methyl adenine (3-MA) or Wortmannin. The autophagy was confirmed from the results of transmission electron microscopy and light microscopy as well as with confocal microscopy. It is tempting to speculate that during ischaemia and reperfusion autophagy along with enhanced survival signals helps to recover the cells from injury.

Telmisartan ameliorates experimental autoimmune myocarditis associated with inhibition of inflammation and oxidative stress

Excess cytokine produced by inflammatory stimuli contributes to the progression of myocardial damage in myocarditis. Angiotensin-II has been shown to play a pivotal role in the pathophysiology of various organs, especially the cardiovascular system. Some angiotensin II type 1 receptor antagonists are reported to inhibit proinflammatory cytokine production in vitro and in vivo. We investigated whether telmisartan, an angiotensin II type 1 receptor antagonist protects against experimental autoimmune myocarditis by suppression of inflammatory cytokines and oxidative stress. Experimental autoimmune myocarditis was induced in Lewis rats by immunization with porcine cardiac myosin. The rats were divided into two groups and treated with either telmisartan (10mg/kg/day) or vehicle for 21days. Age-matched normal rats without immunization were also included in this study. Myocardial functional parameters were significantly improved by treatment with telmisartan compared with vehicle-treated rats. Increased myocardial mRNA expressions of inflammatory cytokines [interleukin (IL-6), IL-1β, tumor necrosis factor-α and interferon-γ] were also suppressed by telmisartan treatment compared with vehicle-treated rats. Myocardial protein expressions of NADPH oxidase subunits p47phox, Nox-4, and gp91phox, myocardial levels of 8-hydroxydeoxyguanosine and 4-hydroxy-2-nonenal, and myocardial apoptosis were also significantly decreased by telmisartan treatment compared with vehicle-treated rats. Further, telmisartan significantly decreased endoplasmic reticulum stress markers in experimental autoimmune myocarditis rats. These findings suggest that telmisartan protects against experimental autoimmune myocarditis in rats, at least in part by suppressing inflammatory cytokines and oxidative stress; however, further investigations are needed before clinical use.

Myocyte turnover in the aging human heart

RATIONALE

The turnover of cardiomyocytes in the aging female and male heart is currently unknown, emphasizing the need to define human myocardial biology.

OBJECTIVE

The effects of age and gender on the magnitude of myocyte regeneration and the origin of newly formed cardiomyocytes were determined.

METHODS AND RESULTS

The interaction of myocyte replacement, cellular senescence, growth inhibition, and apoptosis was measured in normal female (n=32) and male (n=42) human hearts collected from patients 19 to 104 years of age who died from causes other than cardiovascular diseases. A progressive loss of telomeric DNA in human cardiac stem cells (hCSCs) occurs with aging and the newly formed cardiomyocytes inherit short telomeres and rapidly reach the senescent phenotype. Our data provide novel information on the superior ability of the female heart to sustain the multiple variables associated with the development of the senescent myopathy. At all ages, the female heart is equipped with a larger pool of functionally competent hCSCs and younger myocytes than the male myocardium. The replicative potential is higher and telomeres are longer in female hCSCs than in male hCSCs. In the female heart, myocyte turnover occurs at a rate of 10%, 14%, and 40% per year at 20, 60, and 100 years of age, respectively. Corresponding values in the male heart are 7%, 12%, and 32% per year, documenting that cardiomyogenesis involves a large and progressively increasing number of parenchymal cells with aging. From 20 to 100 years of age, the myocyte compartment is replaced 15 times in women and 11 times in men.

CONCLUSIONS

The human heart is a highly dynamic organ regulated by a pool of resident hCSCs that modulate cardiac homeostasis and condition organ aging.

Modulation of doxorubicin-induced cardiac dysfunction in dominant-negative p38α mitogen-activated protein kinase mice

Doxorubicin (Dox) is a widely used antitumor drug, but its application is limited because of its cardiotoxic side effects. Increased expression of p38α mitogen-activated protein kinase (MAPK) promotes cardiomyocyte apoptosis and is associated with cardiac dysfunction induced by prolonged agonist stimulation. However, the role of p38α MAPK is not clear in Dox-induced cardiac injury. Cardiac dysfunction was induced by a single injection of Dox into wild-type (WT) mice and transgenic mice with cardiac-specific expression of a dominant-negative mutant form of p38α MAPK (TG). Left ventricular (LV) fractional shortening and ejection fraction were higher and the expression levels of phospho-p38 MAPK and phospho-MAPK-activated mitogen kinase 2 were significantly suppressed in TG mouse heart compared to WT mice after Dox injection. Production of LV proinflammatory cytokines, cardiomyocyte DNA damage, myocardial apoptosis, caspase-3-positive cells, and phospho-p53 expression were decreased in TG mice after Dox injection. Moreover, LV expression of NADPH oxidase subunits and reactive oxygen species was significantly less in TG mice compared to WT mice after Dox injection. These findings suggest that p38α MAPK may play a role in the regulation of cardiac function, oxidative stress, and inflammatory and apoptotic mediators in the heart after Dox administration.

Beneficial effects of olmesartan, an angiotensin II receptor type 1 antagonist, in rats with dilated cardiomyopathy

Favorable effects of angiotensin II type 1 receptor blockers on patients with ischemic or idiopathic dilated cardiomyopathy (DCM) have already been suggested by several human trials, but their effects on DCM remain unknown. Hence, we investigated the effect of olmesartan on myocardial remodeling in a rat model in which myosin-induced experimental autoimmune myocarditis (EAM) might develop into DCM. EAM was elicited in Lewis rats by immunization with cardiac myosin, and 28 d after immunization, the surviving Lewis rats were divided into two groups and treated with either olmesartan (10 mg/kg/d) or vehicle. Age-matched normal rats without immunizations were also used. After four weeks of treatment, we investigated the effects of olmesartan on cardiac function, inflammatory cytokines and cardiac remodeling in EAM rats. Myocardial functional parameters measured by hemodynamic and echocardiographic analyses were significantly improved by the treatment with olmesartan compared with those of vehicle-treated rats. Olmesartan significantly reduced cardiac fibrosis as well as hypertrophy and its molecular markers (left ventricular [LV] mRNA expressions of transforming growth factor beta1, collagen-I and -III, and atrial natriuretic peptide) compared with those of vehicle-treated rats. Increased myocardial mRNA expressions of proinflammatory cytokines (interleukin [IL]-6, IL-1β), monocyte chemoattractant protein-1 and matrix metalloproteinases (MMP-2 and -9) were also suppressed by the treatment with olmesartan in rats with DCM. Further, the plasma level of angiotensin II was significantly increased in olmesartan-treated rats. These findings demonstrate that olmesartan treatment significantly improved LV function and ameliorated the progression of cardiac remodeling in rats with DCM after EAM.

Downregulation of cardiac lineage protein-1 confers cardioprotection through the upregulation of redox effectors

CLP-1, the mouse homologue of human Hexim1 protein, exerts inhibitory control on transcriptional elongation factor-b of RNA transcript elongation. Previously, we have demonstrated that downregulation of cardiac lineage protein-1 (CLP-1) in CLP-1(+/-) heterozygous mice affords cardioprotection against ischemia-reperfusion injury. Our current study results show that the improvement in cardiac function in CLP-1(+/-) mice after ischemia-reperfusion injury is achieved through the potentiation of redox signaling and their molecular targets including redox effector factor-1, nuclear factor erythroid 2-related factor, and NADPH oxidase 4 and the active usage of thioredoxin-1, thioredoxin-2, glutaredoxin-1 and glutaredoxin-2. Our results suggest that drugs designed to down regulate CLP-1 could confer cardioprotection through the potentiation of redox cycling.

Cardioprotection by resveratrol: a novel mechanism via autophagy involving the mTORC2 pathway

AIMS

On the basis of our previous reports that cardioprotection induced by ischaemic preconditioning induces autophagy and that resveratrol, a polyphenolic antioxidant present in grapes and red wine induces preconditioning-like effects, we sought to determine if resveratrol could induce autophagy.

METHODS AND RESULTS

Resveratrol at lower doses (0.1 and 1 microM in H9c2 cardiac myoblast cells and 2.5 mg/kg/day in rats) induced cardiac autophagy shown by enhanced formation of autophagosomes and its component LC3-II after hypoxia-reoxygenation or ischaemia-reperfusion. The autophagy was attenuated with the higher dose of resveratrol. The induction of autophagy was correlated with enhanced cell survival and decreased apoptosis. Treatment with rapamycin (100 nM), a known inducer of autophagy, did not further increase autophagy compared with resveratrol alone. Autophagic inhibitors, wortmannin (2 microM) and 3-methyladenine (10 mM), significantly attenuated the resveratrol-induced autophagy and induced cell death. The activation of mammalian target of rapamycin (mTOR) was differentially regulated by low-dose resveratrol, i.e. the phosphorylation of mTOR at serine 2448 was inhibited, whereas the phosphorylation of mTOR at serine 2481 was increased, which was attenuated with a higher dose of resveratrol. Although resveratrol attenuated the activation of mTOR complex 1, low-dose resveratrol significantly induced the expression of Rictor, a component of mTOR complex 2, and activated its downstream survival kinase Akt (Ser 473). Resveratrol-induced Rictor was found to bind with mTOR. Furthermore, treatment with Rictor siRNA attenuated the resveratrol-induced autophagy.

CONCLUSION

Our results indicate that at lower dose, resveratrol-mediated cell survival is, in part, mediated through the induction of autophagy involving the mTOR-Rictor survival pathway.