Abstract P337: CD36 Is Required To Prime Cardiomyocytes For Proliferation

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Aboubakr M Salama ◽  
Riham Abouleisa ◽  
Qinghui Ou ◽  
Ahmed Gibreil ◽  
Tamer Mohamed

Many approaches have been explored to regenerate the heart muscle followingischemic injury, out of which is the induction of cardiomyocytes proliferation. Ourprevious work demonstrated that cell-cycle was successfully induced incardiomyocytes by viral expression of combination of four cell-cycle factors: cyclinB1, CDK1, cyclin D1 and CDK4; termed as 4 factors (4F). However, only 15-20 % ofthe cells expressing the four factors progress into cell-cycle, while the remainderare quiescent. A pertinent question in the field of cardiac regeneration is why allviral or in vivo transgenic approaches to induce adult cardiomyocyte proliferation,e.g., 4F, YAP, and CyclinA2, promote proliferation in only a subset ofcardiomyocytes. This general finding suggests that factors or conditions beyondcell-cycle induction influence the probability and perpetuation of cardiomyocytedivision.Here we aim to investigate why only a subpopulation of cardiomyocytes is able toprogress through cell-cycle.Temporal single cell RNA sequencing of 60 days mature hiPS-CMs 24, 48 and 72hours post infection with 4F or control virus revealed that a unique population ofcardiomyocytes in the LacZ control group [1026 cells out of 6761 cells (~15%)] thatdisappears after treatment with 4F; another unique cluster with similar cellnumbers appears 24 h after 4F transduction (Cluster 3), which suggests that theinitial population was primed to proliferate. One of the major characteristics of thisprimed subpopulation is the expression of CD36, a major fatty acids transporter incardiomyocytes, and that 4F induction of cell-cycle completely abolishes CD36expression. knocking down CD36 in hiPS-CMs for 48 hours followed by induction ofproliferation using 4F led to 50-70% reduction in proliferation capacity of thecardiomyocytes compared to the control cells. Furthermore, cardiomyocytesisolated at P7 from CD36 knockout mice showed 30-40 % reduction incardiomyocytes proliferation capacity at baseline and after 4F induction ofproliferation compared to cardiomyocytes isolated from WT controls.These findings suggest that CD36 is needed to prime the CMs to proliferate, andthis can be, at least partially, through provision of energy requirements throughβ-oxidation of fatty acids.

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Riham Abouleisa ◽  
Qinghui Ou ◽  
Xian-liang Tang ◽  
Mitesh Solanki ◽  
Yiru Guo ◽  
...  

Rationale: The regenerative capacity of the heart to repair itself after myocardial infarction (MI)is limited. Our previous study showed that ectopic introduction of Cdk1/CyclinB1 andCdk4/CyclinD1 complexes (4F) promotes cardiomyocyte proliferation in vitro and in vivo andimproves cardiac function after MI. However, its clinical application is limited due to the concernsfor tumorigenic potential in other organs. Objectives: To first, identify on a single cell transcriptomic basis the necessary reprogrammingsteps that cardiomyocytes need to undertake to progress through the proliferation processfollowing 4F overexpression, and then, to determine the pre-clinical efficacy of transient andcardiomyocyte specific expression of 4F in improving cardiac function after MI in small and largeanimals. Methods and Results: Temporal bulk and single cell RNAseq of mature hiPS-CMs treated with4F or LacZ control for 24, 48, or 72 h revealed full cell cycle reprogramming in 15% of thecardiomyocyte population which was associated with sarcomere disassembly and metabolicreprogramming. Transient overexpression of 4F specifically in cardiomyocytes was achievedusing non-integrating lentivirus (NIL) driven by TNNT2 (TNNT2-4F-NIL). One week after inductionof ischemia-reperfusion injury in rats or pigs, TNNT2-4F-NIL or control virus was injectedintramyocardially. Compared with controls, rats or pigs treated with TNNT2-4F-NIL showed a 20-30% significant improvement in ejection fraction and scar size four weeks after treatment, asassessed by echocardiography and histological analysis. Quantification of cardiomyocyteproliferation in pigs using a novel cytokinesis reporter showed that ~10% of the cardiomyocyteswithin the injection site were labelled as daughter cells following injection with TNNT2-4F-NILcompared with ~0.5% background labelling in control groups. Conclusions: We provide the first understanding of the process of forced cardiomyocyteproliferation and advanced the clinical applicability of this approach through minimization ofoncogenic potential of the cell cycle factors using a novel transient and cardiomyocyte-specificviral construct.


2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Wen-Feng Cai ◽  
Guan-Sheng Liu ◽  
Lei Wang ◽  
Christian Paul ◽  
Zhi-Li Wen ◽  
...  

Cardiac regeneration is a homeostatic cardiogenic process by which the sections of malfunctioning adult cardiovascular tissues are repaired and renewed employing a combination of both cardiomyogenesis and angiogenesis. Unfortunately, while high-quality regeneration can be performed in amphibians and zebrafish hearts, mammalian hearts do not respond in kind. Indeed, a long-term loss of proliferative capacity in mammalian adult cardiomyocytes in combination with dysregulated induction of tissue fibrosis impairs mammalian endogenous heart regenerative capacity, leading to deleterious cardiac remodeling at the end stage of heart failure. Interestingly, several studies have demonstrated that cardiomyocyte proliferation capacity is retained in mammals very soon after birth, and cardiac regeneration potential is correspondingly preserved in some preadolescent vertebrates after myocardial infarction. There is therefore great interest in uncovering the molecular mechanisms that may allow heart regeneration during adult stages. This review will summarize recent findings on cardiac regenerative regulatory mechanisms, especially with respect to extracellular signals and intracellular pathways that may provide novel therapeutics for heart diseases. Particularly, bothin vitroandin vivoexperimental evidences will be presented to highlight the functional role of these signaling cascades in regulating cardiomyocyte proliferation, cardiomyocyte growth, and maturation, with special emphasis on their responses to heart tissue injury.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
Y S Tseng ◽  
M Y You ◽  
Y C Hsu ◽  
K C Yang

Abstract Background Although the adult mammalian heart fails to regenerate after injury, it is known that newborn mice within a week have full cardiac regenerative capacity. The molecular determinants underlying the disparate regenerative capacity between neonatal and adult mice, however, remain incompletely understood. Exploiting RNA sequencing in isolated cardiomyocytes from neonatal and adult mouse heart, we identified Cdh2, which encodes the adherence junction protein N-cadherin, as a potential novel mediator of cardiac regeneration. Cdh2 expression levels were much higher in neonatal, compared with adult, cardiomyocytes and showed a strong positive correlation with that of multiple cell cycle genes. N-cadherin has been reported to be essential for embryonic cardiac development; its role in cardiac regeneration, however, remains unknown. Purpose To determine the role of Cdh2 (N-cadherin) in cardiac regeneration and to investigate the underlying molecular mechanisms. Methods Apical resection in postnatal day 1 mice was used as a cardiac regenerative model. The in vitro gain/loss-of function studies of Cdh2/N-cadherin was performed in postnatal day 1 neonatal mouse cardiomyocytes (P1CM) and human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM). N-cadherin inhibitor exherin was used to study the effects of N-cadherin in vivo. Results Comparing to sham-operated control, Cdh2 was significantly upregulated in mouse cardiac apex and border zone following apical resection, which was accompanied with increased cardiomyocyte proliferation activity. In vitro, knocking down Cdh2 or inhibition of N-cadherin activity with exherin in P1CM significantly reduced the proliferative activity of cardiomyocytes, whereas overexpression of Cdh2 markedly increased the proliferation of P1CM. In addition, forced expression of Cdh2 resulted in significant upregulation of multiple cell cycle genes, including Ccnd1 (Cyclin D1) and Pcna (proliferating cell nuclear antigen), in P1CM. In vivo inhibition of N-cadherin in P1 neonatal mice with exherin following apical resection impaired cardiac regeneration and increased scar formation (Figure). Knocking down CDH2 in human iPSC-CMs significantly reduced the proliferative activity and the expression levels of cell cycle gene CCND1 in iPSC-CMs. Mechanistically, we demonstrated that the pro-mitotic effects of N-cadherin in cardiomyocytes were mediated, at least partially, by stabilizing β-catenin, a pro-mitotic transcription factor, through direct interaction with its cytoplasmic domain and/or inactivation of GSK3β, a critical component of β-catenin destruction complex. N-Cad blocker impairs heart regeneration Conclusion Our study uncovered a previously unrecognized role of Cdh2 (N-cadherin) in cardiomyocyte proliferation and cardiac regeneration. Enhancing cardiac expression or activity of N-cadherin, therefore, could be a potential novel therapeutic approach to promote cardiac regeneration and restore cardiac function in adult heart following injury.


2021 ◽  
Author(s):  
Akane Sakaguchi ◽  
Miwa Kawasaki ◽  
Kozue Murata ◽  
Hidetoshi Masumoto ◽  
Wataru Kimura

AbstractMammalian cardiomyocytes have the ability to proliferate from the embryonic stage until early neonatal stage, with most of them being arrested from the cell cycle shortly after birth. Therefore, adult mammalian heart cannot regenerate myocardial injury. Despite much attention, pharmacological approaches for the induction of cardiomyocyte proliferation and heart regeneration have yet to be successful. To induce cardiomyocyte proliferation by drug administration, we focused on benzyl isothiocyanate (BITC). Firstly, we showed that BITC induces cardiomyocyte proliferation both in vitro and in vivo through the activation of the cyclin-dependent kinase (CDK) pathway. In addition, we demonstrated that BITC treatment induces heart regeneration in the infarcted neonatal heart even after the regeneration period. Furthermore, we administered BITC to adult mice in parallel with mild hypoxia (10% O2) treatment and showed that a combination of BITC administration and mild hypoxia exposure induces cell cycle reentry in the adult heart. The present study suggests that pharmacological activation of the CDK pathway with BITC concurrently with the activation of hypoxia-related signaling pathways may enable researchers to establish a novel strategy to induce cardiac regeneration in patients with heart disease.


2017 ◽  
Vol 123 (6) ◽  
pp. 1676-1681 ◽  
Author(s):  
Wataru Kimura ◽  
Yuji Nakada ◽  
Hesham A. Sadek

The underlying cause of systolic heart failure is the inability of the adult mammalian heart to regenerate damaged myocardium. In contrast, some vertebrate species and immature mammals are capable of full cardiac regeneration following multiple types of injury through cardiomyocyte proliferation. Little is known about what distinguishes proliferative cardiomyocytes from terminally differentiated, nonproliferative cardiomyocytes. Recently, several reports have suggested that oxygen metabolism and oxidative stress play a pivotal role in regulating the proliferative capacity of mammalian cardiomyocytes. Moreover, reducing oxygen metabolism in the adult mammalian heart can induce cardiomyocyte cell cycle reentry through blunting oxidative damage, which is sufficient for functional improvement following myocardial infarction. Here we concisely summarize recent findings that highlight the role of oxygen metabolism and oxidative stress in cardiomyocyte cell cycle regulation, and discuss future therapeutic approaches targeting oxidative metabolism to induce cardiac regeneration.


2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Daniela Liccardo ◽  
Ryan LaCanna ◽  
Ying Tian

In contrast to adult, neonatal cardiomyocytes are able to proliferate and lose this capacity soon after birth when they withdraw from the cell cycle, become binucleated and differentiate. The arrest of cardiomyocytes cell cycle can be reversible for a short period, conferring the neonatal heart a regenerative potential within the first week of postnatal life. In the timeframe surrounding birth, heart maturation is also characterized by a change in energy metabolism, switching from glycolysis to beta-oxidation. However little is known about how metabolic programming in postnatal cardiomyocytes regulates their ability to proliferate, become binucleated and differentiate. In this study, we show that blocking beta-oxidation in mouse neonatal cardiomyocytes with etomoxir treatment promotes glycolysis and cell cycle re-entry, while increasing fatty acid beta-oxidation but reducing glycolysis leads to a decrease of the number of proliferating cardiomyocytes. In neonatal mice our data demonstrate that cardiomyocytes undergo binucleation and differentiation during the first week after birth and this process is correlated with the upregulation of the natriuretic peptides, ANP and BNP expression. Notably, in the postnatal mouse heart, beta-oxidation blockade through in vivo etomoxir injections, increases ventricular cardiomyocytes number, decreases natriuretic peptides expression and reduces the conversion of cardiomyocytes from a mononucleated to a binucleated phenotype. These findings highlight the importance of metabolic programming in regulating cardiomyocyte proliferation and suggest a potential therapeutic target for heart regeneration by modulating energy metabolic programming.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Caitlin O’Meara ◽  
Joseph Wamstad ◽  
Laurie Boyer ◽  
Richard T Lee

Some higher organisms, such as zebrafish and neonatal mice, are capable of complete and sufficient regeneration of the myocardium following injury, which is thought to occur primarily by proliferation of pre-existing cardiomyocytes. Although adult humans and adult mice lack this cardiac regeneration potential, there is great interest in understanding how regeneration can occur in the heart so that we can activate this process in humans suffering from heart failure. The aim of our study was to identify mechanisms by which mature, post-mitotic adult cardiomyocytes can re-enter the cell cycle to ultimately facilitate heart regeneration following injury. We derived a core transcriptional signature of injury-induced cardiomyocyte regeneration in mouse by comparing global transcriptional programs in a dynamic model of in vitro and in vivo cardiomyocyte differentiation and in an in vitro cardiomyocyte explant model, as well as a neonatal heart resection model. We identified a panel of transcription factors, growth factors, and cytokines, whose expression significantly correlated with the differentiated state of the cell in all datasets examined, suggesting that these factors play a role in regulating cardiomyocyte cell state. Furthermore, potential upstream regulators of core differentially expressed networks were identified using Ingenuity Pathway Analysis and we found that one predicted regulator, interleukin-13 (IL13), significantly induced cardiomyocyte cell cycle activity and STAT6/STAT3 signaling in vitro. siRNA knockdown experiments demonstrated that STAT3/periostin and STAT6 signaling are critical for cardiomyocyte cell cycle activity in response to IL13. These data reveal novel insights into the transcriptional regulation of mammalian heart regeneration and provide the founding circuitry for identifying potential regulators for stimulating cardiomyocyte cell cycle activity.


2020 ◽  
Vol 21 (6) ◽  
pp. 2186
Author(s):  
Wei-Yu Chen

Heart disease is the leading cause of death worldwide. The major cause of heart failure is the death of the myocardium caused by myocardial infarction, detrimental cardiac remodeling, and cardiac fibrosis occurring after the injury. This study aimed at discovering the role of the anti-aging protein α-klotho (KL), which is the co-receptor of fibroblast growth factor-23 (FGF23), in cardiac regeneration, fibrosis, and repair. We found that the anti-apoptotic function of soluble KL in isoproterenol-treated H9c2 cardiomyocytes was independent of FGF23 in vitro. In vivo, isoproterenol-induced cardiac fibrosis and cardiomyocyte and endothelial cell apoptosis were reduced by KL treatment. Moreover, the number of Ki67-positive endothelial cells and microvessel density within the isoproterenol-injured myocardium were increased upon KL treatment. However, by using genetic fate-mapping models, no evident cardiomyocyte proliferation within the injured myocardium was detected with or without KL treatment. Collectively, the cardioprotective functions of KL could be predominantly attributed to its anti-apoptotic and pro-survival activities on endothelial cells and cardiomyocytes. KL could be a potential cardioprotective therapeutic agent with anti-apoptotic and pro-survival activities on cardiomyocytes and endothelial cells.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1549 ◽  
Author(s):  
Marta Grodzik ◽  
Jaroslaw Szczepaniak ◽  
Barbara Strojny-Cieslak ◽  
Anna Hotowy ◽  
Mateusz Wierzbicki ◽  
...  

Our previous studies have shown that diamond nanoparticles (NDs) exhibited antiangiogenic and proapoptotic properties in vitro in glioblastoma multiforme (GBM) cells and in tumors in vivo. Moreover, NDs inhibited adhesion, leading to the suppression of migration and invasion of GBM. In the present study, we hypothesized that the NDs might also inhibit proliferation and cell cycle in glioma cells. Experiments were performed in vitro with the U87 and U118 lines of GBM cells, and for comparison, the Hs5 line of stromal cells (normal cells) after 24 h and 72 h of treatment. The analyses included cell morphology, cell death, viability, and cell cycle analysis, double timing assay, and gene expression (Rb, E2F1, CycA, CycB, CycD, CycE, PTEN, Ki-67). After 72 h of ND treatment, the expression level of Rb, CycD, and CycE in the U118 cells, and E2F1, CycD, and CycE in the U87 cells were significantly lower in comparison to those in the control group. We observed that decreased expression of cyclins inhibited the G1/S phase transition, arresting the cell cycle in the G0/G1 phase in glioma cells. The NDs did not affect the cell cycle as well as PTEN and Ki-67 expression in normal cells (Hs5), although it can be assumed that the NDs reduced proliferation and altered the cell cycle in fast dividing cells.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 318-318 ◽  
Author(s):  
Lequn Li ◽  
Hui Wang ◽  
Vassiliki A. Boussiotis

Abstract Cell cycle re-entry of quiescent T lymphocytes is required for generation of productive T cell responses. Cyclin-dependent kinases (cdk), particularly cdk2, have an essential role in cell cycle re-entry. Cdk2 promotes phosphorylation of Rb and related pocket proteins thereby reversing their ability to sequester E2F transcription factors. Besides Rb, cdk2 phosphorylates Smad2 and Smad3. Smad3 inhibits cell cycle progression from G1 to S phase, and impaired phosphorylation on the cdk-mediated sites renders it more effective in executing this function. In contrast, cdk-mediated phosphorylation of Smad3 reduces Smad3 transcriptional activity and antiproliferative function. Recently, we determined that induction of T cell tolerance resulted in impaired cdk2 activity, leading to reduced levels of Smad3 phosphorylation on cdk-specific sites and increased Smad3 antiproliferative function due to upregulation of p15. We hypothesized that pharmacologic inhibition of cdk2 during antigen-mediated T cell stimulation might provide an effective strategy to control T cell expansion and induce tolerance. (R)-roscovitine (CYC202) is a potent inhibitor of cdk2-cyclin E, which in higher concentrations also inhibits other cdk-cyclin complexes including cdk7, cdk9 and cdk5. It is currently in clinical trials as anticancer drug and recently was shown to induce long-lasting arrest of murine polycystic kidney disease. We examined the effect of roscovitine on T cell responses in vitro and in vivo. We stimulated C57BL/6 T cells with anti-CD3-plus-anti-CD28 mAbs, DO11.10 TCR-transgenic T cells with OVA peptide or C57BL/6 T cells with MHC disparate Balb/c splenocytes. Addition of roscovitine in these cultures resulted in blockade of cell proliferation without induction of apoptosis. Biochemical analysis revealed that roscovitine prevented phosphorylation of cdk2, downregulation of p27, phosphorylation of Rb and synthesis of cyclin A, suggesting an effective G1/S cell cycle block. To determine whether roscovitine could also inhibit clonal expansion of activated T cells in vivo, we employed a mouse model of GvHD. Recipient (C57BL/6 x DBA/2) F1 mice were lethally irradiated and were subsequently infused with bone marrow cells and splenocytes, as source of allogeneic T cells, from parental C57BL/6 donors. Roscovitine or vehicle-control was given at the time of allogeneic BMT and on a trice-weekly basis thereafter for a total of three weeks. Administration of roscovitine protected against acute GvHD resulting in a median survival of 49 days in the roscovitine-treated group compared to 24 days in the control group (p=0.005), and significantly less weight loss. Importantly, roscovitine treatment had no adverse effects on engraftment, resulting in full donor chimerism in the treated mice. To examine whether tolerance had been induced by in vivo treatment with roscovitine, we examined in vitro rechallenge responses. While control C57BL/6 T cells exhibited robust responses when stimulated with (C57BL/6 x DBA/2) F1 splenocytes, responses of T cells isolated from roscovitine-treated recipients against (C57BL/6 x DBA/2) F1 splenocytes were abrogated. These results indicate that roscovitine has direct effects on preventing TCR-mediated clonal expansion in vitro and in vivo and may provide a novel therapeutic approach for control of GvHD.


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