CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Durante a realizaÃÃo de transplantes renais e outras operaÃÃes sobre os rins ocorrem os fenÃmenos de isquemia/reperfusÃo cujos efeitos nocivos colocam em risco o sucesso dessas intervenÃÃes. Pesquisas tÃm sido feitas no sentido de controlar, ou ao menos diminuir, os efeitos indesejÃveis da isquemia/reperfusÃo. O objetivo desse estudo à avaliar o possÃvel efeito da l-alanil-glutamina sobre a isquemia/reperfusÃo renal mediante a determinaÃÃo, in vivo, das concentraÃÃes de glicose, piruvato, lactato e corpos cetÃnicos no sangue e no tecido renal submetido a isquemia/reperfusÃo. Isquemia de 30 min. foi induzida em dois grupos de animais de experimentaÃÃo (ratos Wistar). Em seguida, foram determinadas as alteraÃÃes ocorridas no tempo pÃs-reperfusÃo (0 min., 5mi., 15 min., 30 min.) nas concentraÃÃes sangÃÃneas e renais de glicose, piruvato, lactato e corpos cetÃnicos. Um grupo de 24 animais (6 para cada tempo) foi previamente tratado com l-alanil-glutamina administrada por via venosa e na dose de 0,75g /kg de peso. Em grupo controle com igual nÃmero de animais administrou-se, tambÃm por via venosa, o mesmo volume de soluÃÃo salina. Os resultados apontam para aumento significante na concentraÃÃo sangÃÃnea de lactato nos animais que receberam l-alanil-glutamina, logo apÃs a isquemia (tempo 0 min.) e em todos os tempos apÃs a reperfusÃo. NÃo foram constatadas alteraÃÃes significantes nas concentraÃÃes de piruvato e de glicose. No entanto, foi observada reduÃÃo significante na concentraÃÃo de corpos cetÃnicos. Os resultados obtidos sugerem aumento da atividade glicolÃtica durante o perÃodo de reperfusÃo decorrente da oferta exÃgena de l-alanil-glutamina. Tal fato deve-se, provavelmente, à ativaÃÃo do sistema carreador malato-aspartato, em razÃo da oferta de glutamato, atravÃs de seu precursor l-glutamina. / Renal tranplantation and other operations give rise to kidney ischemia/ reperfusion injuries that may interfere with the final outcome. The purpose of this study is to examine the effects of l-alanil-glutamine pre-treatment in rats subjected to renal ischemia/reperfusion. Twenty -four rats were distributed in 4 subgroups of 6 animals. Half an hour following administation of l-alanil-glutamine (0,75 g/Kg) animals were subjected to kidney ischemia during 30 minutes. Kidney arterial blood samples were collected at the end of the ischemia and 5,15 and 30 minutes later. Glucose pyruvate lactate and cetonic bodies in vivo concentrations were determined in all samples. A second group of 24 animals received i.v.saline solution pre-treatment half an hour prior to the experiment. Laboratory analysis revealed a significant increase in blood concentration of lactate in l-alanil âglutamine group and during reperfusion. The offer of l-alanil-glutamine cause no significant change on concentration of glucose and pyruvate. On the other hand it did induce to significant reduction of cetonemia in the animal group treated with l-alanil-glutamine as compared to that observed in animals from control group. It is concluded that l-alanil âglutamine pre â treatment may enhance glycolysis during ischemia-reperfusion. Activation of malate-aspartate shuttle in glucose oxidative pathway due to increase availabitity of glutamate can explain these changes.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2018-01-30T16:51:18Z No. of bitstreams: 2 Dissertação - Patricia de Almeida Machado Gonçalves - 2017.pdf: 2160802 bytes, checksum: 939d23474b7308d62b12f4b66224829d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-01-31T14:31:11Z (GMT) No. of bitstreams: 2 Dissertação - Patricia de Almeida Machado Gonçalves - 2017.pdf: 2160802 bytes, checksum: 939d23474b7308d62b12f4b66224829d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-01-31T14:31:11Z (GMT). No. of bitstreams: 2 Dissertação - Patricia de Almeida Machado Gonçalves - 2017.pdf: 2160802 bytes, checksum: 939d23474b7308d62b12f4b66224829d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-12-18 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Oxidative stress is the overproduction of reactive oxygen species that cause cell damage and even the death. It is a mechanism related to ischemia and reperfusion, a process that affects several organs and is involved in neurodegenerative diseases, cardiac and/or renal insufficiencies, hepatic dysfunction, among others. The discovery of new antioxidant substances derived from natural sources, is important for the prevention and treatment of these diseases. Beta lapachone is a substance with antioxidant action obtained from sawdust of Ipe wood, a symbolic tree from the Brazilian cerrado. This study aimed to analyze the cytotoxic and antioxidant action of beta lapachone in endothelial cells, in vitro. EA.hy 926 lineage cells were subcultured, treated with different concentrations of beta lapachone and subjected to ischemia and reperfusion. Cytotoxicity and antioxidant action were assessed through the cellular viability analysis by the tetrazolium reduction method. The averages were verified by the Tukey test (5% of significance) and by variance analysis. There was a dose-dependent progression of cytotoxicity in the non-ischemia/reperfusion (control) group and cell viability increase in the ischemia/reperfusion group. However, there was no statistical difference between the concentrations and between groups. Considering the settings of this experiment, Beta lapachone did not present cytotoxic or antioxidant action on endothelial cells. / O estresse oxidativo é o excesso de produção de espécies reativas de oxigênio que causam danos e até a morte das células. É um mecanismo que pode se originar da isquemia e reperfusão, um processo que acomete diversos órgãos e que está envolvido em doenças neurodegenerativas, cardíacas, insuficiências renais, disfunção hepática, entre outras. A necessidade da descoberta de novas substâncias antioxidantes, derivadas de fontes naturais, é importante para a prevenção e tratamento dessas doenças. A beta lapachona é uma substância com ação antioxidante, obtida da serragem da madeira do ipê, vegetação símbolo do cerrado brasileiro. Neste estudo objetivou-se analisar a ação citotóxica e antioxidante da beta lapachona em células endoteliais, in vitro. Células da linhagem EA.hy 926 foram subcultivadas, tratadas com a β lapachona em diferentes concentrações e submetidas à isquemia e reperfusão. A citotoxidade e a ação antioxidante foram obtidas por meio da análise da viabilidade celular pelo método de redução do tetrazólio. As médias foram averiguadas pelo teste de Tukey (5% de significância) e pela análise de variância. Houve progressão dose dependente da citotoxidade no grupo sem isquemia/reperfusão e da viabilidade celular no grupo com isquemia/reperfusão. No entanto, não houve diferença estatística entre as concentrações e entre os grupos. A beta lapachona, nas condições desse experimento, não apresentou ação citotóxica ou antioxidante nas células endoteliais.

Introdução: O transplante renal é amplamente reconhecido como a melhor forma de tratamento para os pacientes que necessitam de terapia de substituição renal. Frequentemente a equipe transplantadora se depara com a difícil questão de determinar se órgãos, provenientes de doadores falecidos e limítrofes ou em parada cardíaca, estão aptos para serem transplantados. É difícil quantificar a intensidade do dano provocado pela isquemia no enxerto a ser utilizado, especialmente se o doador apresentou quadro de instabilidade hemodinâmica com queda significativa da perfusão tecidual e aumento do risco de diminuir a função do enxerto e afetar adversamente sua sobrevida. Desta forma torna-se justificável a utilização da técnica de espectroscopia de fluorescência induzida pelo laser, na tentativa de se avaliar a correlação entre os seus achados e o grau de lesão histológica renal experimental, uma vez que se trata de um método objetivo, não invasivo, rápido e em tempo real que, futuramente, pode ser aplicada nos transplantes renais em humanos. Objetivos: Avaliar a correlação entre os dados da espectroscopia de fluorescência induzida pelo laser e alterações histológicas na isquemia e reperfusão renal em ratos, e se existe diferença significativa na leitura da espectroscopia entre os polos superior, inferior e o terço médio. Materiais e Métodos: Foram utilizados 33 ratos (Rattus norvegicus) machos adultos da linhagem Wistar que, depois de anestesiados, tiveram seus rins esquerdos abordados. Inicialmente os rins foram submetidos à detecção da espectroscopia de fluorescência dos pólos superiores, inferiores e terços médios. As excitações foram geradas por lasers com comprimentos de onda de 408, 442 e 532 nm. Em seguida os pedículos renais esquerdos foram dissecados, isolados e clampeados com auxílio de mini-pinça vascular. Então, os animais foram divididos aleatoriamente em três grupos isquêmicos de 30, 60 e 120 minutos de isquemia quente. Em cada um dos grupos, os rins foram novamente analisados pela espectroscopia de fluorescência, bem como após 5 minutos de reperfusão, utilizando novamente feixes excitatórios com os mesmos comprimentos de onda, nas mesmas regiões renais. Posteriormente os rins esquerdos foram coletados e enviados para estudo histológico. Resultados: O tempo de isquemia mostrou forte influência com a graduação histológica. Com 30 minutos de isquemia, nenhum comprimento de onda (408, 442 e 532 nm) apresentou correlação com a graduação histológica (p = 0,81; p = 0,11; p = 0,21, respectivamente). Com 60 minutos de isquemia, o laser de excitação de 532 nm (na fase de reperfusão) apresentou coeficiente de correlação negativa significativa (r = - 0,61) com a graduação histológica. Na isquemia de 120 minutos, o laser com 442 nm de comprimento de onda (na fase de reperfusão) mostrou o coeficiente de correlação negativa significativa (r = - 0,73) com a graduação histológica. O terço médio renal apresentou média estatística superior à dos polos (p < 0,001) na leitura da espectroscopia de fluorescência. Conclusões: Há correlação entre os dados da espectroscopia de fluorescência induzida pelo laser e as alterações histológicas na isquemia renal em ratos, sendo necessário, durante a investigação, analisar apenas o terço médio renal. / Introduction: Renal transplantation is widely recognized as the best form of treatment for patients who require renal replacement therapy. Often, the transplant team is faced with a difficult question, if organs from deceased marginal donors or non-heart beating donors are able to be transplanted. It is difficult to quantify the intensity of damage caused by ischemia in the graft to be used, especially if the donor had hemodynamic instability with a significant decrease of the tissue perfusion and an increased of the risk of diminishing the graft function which could affect adversely its survival. Thus it is justified to use the technique of laser-induced fluorescence spectroscopy, to assess the correlations between its results and the histological grade in experimental renal injury, since it is an objective, non-invasive, fast and in real-time analysis, which can be applied, in the future, in human kidney transplants. Objectives: To evaluate the correlation between the data of laser-induced fluorescence spectroscopy and histological changes in kidney ischemia and reperfusion in rats, and if there are significant differences of reading between the upper and lower poles and the middle area of such kidneys. Materials and Methods: We used 33 adults male rats (Rattus norvegicus) of Wistar strain, which after anesthetized, had their left kidney addressed. Initially such kidneys were submitted to detection of the fluorescence spectroscopy of the upper pole, lower pole and the middle area. Excitations were generated by lasers having wavelengths of 408, 442 and 532 nm. Then the left renal pedicles were dissected, isolated and clamped. Then the animals were randomized into three ischemic groups of 30, 60 and 120 minutes. In each group, the kidneys were analyzed by fluorescence spectroscopy for the second time, and again after 5 minutes of reperfusion, using excitatory beam with same wavelength, at the poles (upper and lower) and the middle area of the kidneys. Later, the left kidney were collected and sent for histological examination. Results: The ischemia time showed a strong influence on the histological grade. With 30 minutes of ischemia, no wavelength (408, 442 and 532 nm) was correlated with the histological lesions (p = 0.81, p = 0.11, p = 0.21, respectively). With 60 minutes of ischemia, the laser excitation of 532 nm (in the reperfusion phase) showed a significant negative correlation coefficient (r = - 0.61) with the histological grading. In 120 minutes of ischemia, laser with 442 nm wavelength (in the reperfusion phase) showed a significant negative correlation coefficient (r = - 0.73) with the histological grade. The middle area of the kidneys showed a higher average statistically (p< 0,001) than the poles in the reading of fluorescence spectroscopy. Conclusions: There is a strong correlation between the data of laser-induced fluorescence spectroscopy and the histological changes in rats renal ischemia, being necessary, during the investigation, to analyze only the middle area of the kidneys.

A transferência de retalhos livres e o reimplante de tecidos têm em comum a exposição dos tecidos à isquemia e tempos de reperfusão variáveis, que são importantes na determinação dos danos celulares estruturais e ultraestruturais, às vezes irreversíveis. O tempo de isquemia dificilmente pode ser controlado no período pré ou transoperatório, mas pode-se tentar prevenir ou diminuir as alterações celulares com soluções preservadoras, como, por exemplo, a da Universidade de Wisconsin, amplamente utilizada na prática clínica dos transplantes de tecidos. Porém a disponibilidade e o custo alto destas soluções dificultam seu uso rotineiro nos centros cirúrgicos. O presente trabalho propõe a utilização de solução de preservação (Solução Plástica-USP) que pode ser facilmente preparada com medicamentos accessíveis e baixo custo; a eficiência desta solução foi comparada com a da solução de Wisconsin. Os resultados demonstraram que não existe diferencia significativa entre a solução Plástica-USP, comparável à solução de Wisconsin; conferindo, ambas, um maior nível de proteção celular sobre os controles; beneficiando significativamente os resultados, e diminuindo assim os riscos de perdas do transplante a baixo custo / The free flaps transfer and reimplantation of tissue has in common the exposure of the tissue to ischemia and different time of reperfusion which are important for the determination of the extent of the cellular injury, being sometimes irreversible. In the pre and trans-surgical procedure the control of the ischemic period is difficult. Although efforts are made to prevent and decrease cellular changes using preservative solution, such as University of Wisconsin (UW) used in routine transplant of organs. The availability and high cost of this solution some time is one problem. The present study was made in a rat model that we have been reported in others works, we proposed the utilization of a preservation solution that we called Plastic Surgery-USP solution (PS-USP); witch can be easily prepared with accessible and low cost drugs. The efficiency of this PS-USP solution was compared to UW; our result showed that there is not significative difference in the protective effects of the PS-USP and UW solutions; both solutions were efficient considering cellular protection to ischemia/reperfusion injury, decreasing the risks of flap lost, with low cost and easy disposition

L’insuffisance rénale aiguë (IRA) est une dysfonction d’organe fréquente. Alors que la fonction rénale récupère le plus souvent, on sait depuis 2009 que le pronostic rénal est malgré tout engagé à long terme. L’objectif de ce travail est d’étudier les mécanismes de réparation pathologique de l’épithélium tubulaire afin de mieux comprendre les conséquences à long terme d’un épisode d’IRA.Le parcours des patients après IRA a été transposé dans un modèle à deux agressions (souris C57Bl6/J) : ischémie-reperfusion rénale, suivie à distance par l’administration continue d’angiotensine 2. L’agression aiguë a été calibrée pour obtenir une récupération fonctionnelle et une histologique (microarchitecture normale à la fin du processus de réparation). La fibrose rénale sous angiotensine 2 était plus importante après un antécédent de nécrose tubulaire ischémique résolutive. En isolant les cellules du tube proximal différenciées, une reprogrammation durable du métabolisme et une probable compartimentalisation de la fibrogénèse ont été mises en évidence.L’hypothèse d’un mécanisme épigénétique, faisant le lien entre ischémie-reperfusion et fibrose à distance, a été explorée. Des modifications d’acétylation des histones dans les cellules tubulaires ont été constatées sur des biopsies des greffons humains en post-IRA. Ces modifications ont été reproduites chez la souris et modélisées in vitro après hypoxie-réoxygénation sur une culture primaire de cellules tubulaires. L’acétylation du locus du gène du micro-ARN miR21, dont les cibles sont impliquées dans la progression de la fibrose, est augmentée après ischémie-reperfusion et associée à son induction. / Acute kidney injury (AKI) is a frequent organ dysfunction. While renal function generally recovers, it has been shown since 2009 that AKI carries a poor long-term renal prognosis. The objective of this study was to investigate the maladaptive repair of the tubular epithelium in order to better understand the long-term consequences of AKI. The course of patients after AKI was transposed into a two-hit animal model (C57Bl6/J mice): renal ischemia-reperfusion, followed by continuous administration of angiotensin 2. AKI was calibrated so as to obtain full functional recovery and normal microarchitecture after ischemic tubular necrosis. There was greater renal fibrosis under angiotensin 2 after a history of resolving ischemic tubular necrosis. By isolating differentiated proximal tubular cells, sustained metabolism reprogramming and compartmentalization of fibrogenesis were highlighted. The hypothesis of an underlying epigenetic mechanism, linking ischemia-reperfusion to fibrosis, was explored. Histone post-translational modifications (H3K18 acetylation) in tubular cells were found in human graft biopsies. These changes were reproduced in mice and modeled in vitro after hypoxia-reoxygenation on a primary culture of tubular cells. Histone acetylation peaked at the locus of the miR21 microRNA gene, whose targets are involved in the progression of fibrosis, and was implicated in miR21 expression following our model of AKI.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Stroke is the third leading cause of death in South Africa, killing about 240 people a day and leaving survivors with residual disabilities. There is no clinically approved neuroprotective agent for stroke at the moment but the consumption of plant polyphenols has been suggested to offer neuroprotection against stroke and other neurodegenerative diseases. In this study, we investigated the effects of long term consumption of fermented rooibos herbal tea (FRHT) on ischemia reperfusion brain injury (I-RBI) in rats. Male adult Wistar rats were fed FRHT ad libitum for 7 weeks prior to the induction of ischemic injury by the transient bilateral occlusion of the common carotid arteries (BCCAO) for 20 minutes followed by 24 hours, 4 and 7 days of reperfusion respectively. Rats were then evaluated for neurologic deficits before sacrifice and brains harvested for assessment of brain oedema, blood-brain-barrier (BBB) integrity through Evans blue extravasation (EBE), immunohistochemical studies of apoptosis and lipid peroxidation. Oxygen radical antioxidant capacity and ferric reducing antioxidant power assays were also conducted to assess total antioxidant capacity after ischemia-reperfusion injury. Notably, the long term consumption of fermented rooibos herbal tea prevented brain oedema by reducing cerebral swelling induced by I-RBI. We also observed that fermented rooibos herbal tea offered neuroprotection against damage to the BBB and delayed neuronal death associated with BCCAO as fewer apoptotic cells were identified 7 days post BCCAO reperfusion. Significantly reduced levels of lipid peroxidation and increased levels of total antioxidant capacity were also observed in brain specimens of rats treated with FRHT. Rats treated with FRHT also showed improved neurologic outcomes when compared with the untreated animals. Our results show that FRHT has potent antioxidant and anti-inflammatory properties which can provide neuroprotective effects against neuronal cell loss, cerebral swelling, BBB disruption, lipid peroxidation and neurologic deficits following I-RBI. The use of FRHT is therefore highly recommended for patients with conditions that predispose them to stroke.

Coronary artery disease remains the leading cause of death in the United States with over 1 million acute coronary events predicted to take place in 2019 alone. Heart failure, a common and deadly sequela of myocardial infarction (MI), is attributed to adverse ventricular remodeling driven by cardiomyocyte death, inflammation, and mechanical factors. Despite strong evidence suggesting the importance of myocardial mechanics in driving cardiac remodeling, many <i>in vivo</i> MI studies still rely on 2D analyses to estimate global left ventricular (LV) function and approximate strain using a linear definition. These metrics, while valuable in evaluating the overall impact of ischemic injury on cardiac health, do not capture regional differences in myocardial contractility. The objective of this work is therefore to expand upon existing ultrasound studies by enabling regional analysis of 3D myocardial strain. By integrating our recently developed four-dimensional ultrasound (4DUS) imaging technique with a direct deformation estimation algorithm for 3D strain, we identified unique remodeling patterns and regional strain differences between two murine models of MI with different infarct severities. By constructing 3D strain maps of the remodeling LVs, we were able to capture strain heterogeneity and characterize a sigmoidal strain profile at infarct border zones. Finally, we demonstrated that the maximum principal component of the 3D Green-Lagrange strain tensor correlates with LV remodeling severity and is predictive of final infarct size. Taken together, the presented work provides a novel and thorough approach to quantify regional 3D strain, an important component when assessing post-MI remodeling.

Au sein du laboratoire, par une stratégie de conception de médicaments par la méthode des fragments, nous avons généré une nouvelle famille d'inhibiteurs de cyclophilines, les SMCypI (« Small-Molecule Cyclophilin Inhibitors »), non liée aux autres inhibiteurs de cyclophilines existants. Les cyclophilines sont des protéines cellulaires impliquées dans un grand nombre de processus biologiques. Toutefois, les inhibiteurs de cyclophilines disponibles possèdent de nombreux inconvénients qui rendent leur utilisation clinique difficile. Au cours de ma thèse nous nous sommes intéressés au développement des SMCypI dans deux domaines en particulier, la Virologie et l’Hépatologie.Dans le domaine de la Virologie, les cyclophilines sont impliquées dans la réplication de plusieurs virus et constituent donc une cible de choix dans le développement d'antiviraux à large spectre. Dans un premier temps, nous nous sommes intéressés à la caractérisation de l’activité antivirale de ces molécules sur le virus de l’Hépatite C, avec comme objectif de démontrer leur activité pangénotypique, leur haute barrière à la résistance, leur mécanisme d’action et leur activité antivirale à large spectre pour d’autres virus de la famille des Flaviviridae.Dans le domaine de l’Hépatologie, les lésions d’ischémie-reperfusion hépatique sont rencontrés pendant la chirurgie hépatique et la transplantation hépatique. La mitochondrie est un acteur majeur via l’ouverture du pore de transition de perméabilité mitochondrial. L’ouverture du pore est modulée par la cyclophiline D. Dans un deuxième temps, nous avons étudié les effets des SMCypI sur cette deuxième cible. Cela nous a permis de démontrer leur effet hépatoprotecteur dans un modèle murin d’ischémie-reperfusion hépatique.L’ensemble de ces résultats ouvre la porte pour le concept des antiviraux à large spectre, et l’utilité dans le domaine de l’hépatologie comme molécules hépatoprotectrices.... / In our laboratory we previously reported a rational design of a new family of smallmolecule cyclophilins inhibitors, SMCypI, unrelated to other cyclophilins inhibitors by means of a complex fragment-based drug discovery approach. Cyclophilins are cellular proteins involved in multiple biological processes. Unfortunately, different disadvantages have limited their clinical development. The aim my thesis was to study the SMCypI in two particulars fields, Virology and Hepatology.In the field of Virology, cyclophilins inhibitors are involved in viral replication of multiple viruses, which make them a convenient target for the development of “broad-spectrum antivirals”. Here, we first characterized the pangenotypic anti-HCV activity of this new family of SMCypI, with high resistance barrier. We studied its mechanism of action andits broad antiviral activity on other members of the Flaviviridae family.In the field of Hepatology, ischemia-reperfusion injuries occur during liver surgery and liver transplantation. Mitochondria play a central role in the opening of mitochondrial permeability transition pore. The opening of this pore is mainly regulated by cyclophilin D. The aim of the second part of our work was to demonstrated a hepatoprotective effect of the SMCypl in a murine model of hepatic ischemia reperfusion injury.Overall, these results are leading the way to the development of broad-spectrumantiviral drugs and their use in hepatology as hepatoprotective drugs....

Cardiovascular disease is a leading cause of death in the United States. Toll-like receptor (TLR)-mediated pathways have been demonstrated to play a role in myocardial ischemia/reperfusion (I/R) injury. We and others have shown that PI3K/Akt signaling is involved in regulating cellular survival and protecting the myocardium from I/R induced injury. In this dissertation, we provide compelling evidence that miR-125b serves to “fine tune” TLR mediated NF-kB responses by repressing TNF-a and TRAF6 expression. We constructed lentiviral expressing miR-125b, delivered it into the myocardium. The data showed that delivery of lentivirus expressing miR-125b significantly reduces myocardial infarct size and improves cardiac function in I/R hearts. Mechanistic studies demonstrated that miR-125b negatively regulates TLR mediated NF-kB activation pathway by repressing TNF-a and TRAF6 expression in the myocardium. We also observed that transfection of the myocardium with lentivirus expressing miR-214 markedly attenuates I/R induced myocardial infarct size and cardiac dysfunction. We demonstrated that miR-214 activates PI3K/Akt signaling by targeting PTEN expression in the myocardium. We also investigated the role of TLR3 in neonatal heart repair and regeneration following myocardial infarction (MI). Wild type (WT) neonatal mice showed fully cardiac functional recovery and small infarct size, while TLR3 deficient mice exhibited impaired cardiac functional recovery and large infarct area after MI. Poly (I:C), a TLR3 ligand, administration significantly enhances glycolysis, YAP1 activation and the proliferation of WT neonatal cardiomyocytes. 2-deoxyglucose (2-DG), a glycolysis inhibitor treatment abolished cardiac functional recovery and YAP1 activation in neonatal mice after MI. In vitro either inhibition of glycolysis by 2-DG or inhibition of YAP1 activation prevents Poly (I:C) induced YAP1 activation and neonatal cardiomyocyte proliferation. Importantly, YAP1 activation increases miR-152 expression, leading to cardiomyocyte proliferation through suppression P27kip1 and DNMT1 expression. We conclude that microRNAs play an important role in TLR modulation induced protection against myocardial I/R injury by increasing the activation of PI3K/Akt signaling pathway, decreasing TLR/NF-kB mediated inflammatory response, and suppressing activation of apoptotic signaling following myocardial I/R injury. In addition, TLR3 is an essential for neonatal heart repair and regeneration after myocardial infarction. TLR3 modulation could be a novel strategy for heart regeneration and repair.

No description available.