scholarly journals Unlocking the Secrets of the Regenerating Fish Heart: Comparing Regenerative Models to Shed Light on Successful Regeneration

2021 ◽  
Vol 8 (1) ◽  
pp. 4
Author(s):  
Helen G. Potts ◽  
William T. Stockdale ◽  
Mathilda T. M. Mommersteeg
Keyword(s):  
Reverse Genetics ◽  
Cardiac Regeneration ◽  
Comparative Approach ◽  
Great Promise ◽  
Candidate Gene Approach ◽  
Fish Heart ◽  
Astyanax Mexicanus ◽  
Fish Model ◽  
Fibrotic Scar ◽  
Shed Light

The adult human heart cannot repair itself after injury and, instead, forms a permanent fibrotic scar that impairs cardiac function and can lead to incurable heart failure. The zebrafish, amongst other organisms, has been extensively studied for its innate capacity to repair its heart after injury. Understanding the signals that govern successful regeneration in models such as the zebrafish will lead to the development of effective therapies that can stimulate endogenous repair in humans. To date, many studies have investigated cardiac regeneration using a reverse genetics candidate gene approach. However, this approach is limited in its ability to unbiasedly identify novel genes and signalling pathways that are essential to successful regeneration. In contrast, drawing comparisons between different models of regeneration enables unbiased screens to be performed, identifying signals that have not previously been linked to regeneration. Here, we will review in detail what has been learnt from the comparative approach, highlighting the techniques used and how these studies have influenced the field. We will also discuss what further comparisons would enhance our knowledge of successful regeneration and scarring. Finally, we focus on the Astyanax mexicanus, an intraspecies comparative fish model that holds great promise for revealing the secrets of the regenerating heart.

Abstract 129: Embryonic Stem Cell Derived Exosomes Revive Endogenous Repair Mechanisms In Failing Heart

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Mohsin Khan ◽  
Suresh K Verma ◽  
Alexander R Mackie ◽  
Erin Vaughan ◽  
Srikanth Garikipati ◽  
...  
Keyword(s):  
Stem Cells ◽  
Therapeutic Potential ◽  
Embryonic Stem ◽  
Cardiac Regeneration ◽  
Great Promise ◽  
Target Cells ◽  
Free System ◽  
Teratoma Formation

Rationale: Embryonic stem cells (ESCs) hold great promise for cardiac regeneration but are susceptible to ethical concerns, lack of autologous donors and teratoma formation. Recently, it has been observed that beneficial effects of stem cells are mediated by exosomes secreted out under various physiological conditions. ESCs have the ability to produce exosomes however their effect in the context of the heart is unknown. Objective: Determine the effect of ESC derived exosomes for cardiac repair and modulation of CPCs functions in the heart following myocardial infarction. Methods and Results: Exosomes were isolated from murine ESCs (mES Ex) or embryonic fibroblasts (MEFs) by ultracentrifugation and verified by Flotillin-1 immunoblot analysis. Induction of pluripotent markers, survival and in vitro tube formation was enhanced in target cells receiving ESC exosomes indicating therapeutic potential of mES Ex. mES Ex administration resulted in enhanced neovascularization, cardiomyocyte survival and reduced fibrosis post infarction consistent with resurgence of cardiac proliferative response. Importantly, mES Ex mediated considerable enhancement of cardiac progenitor cell (CPC) survival, proliferation and cardiac commitment concurrent with increased c-kit+ CPCs in vivo 4 weeks after mES Ex transfer. miRNA Array analysis of ESC and MEF exosomes revealed significantly high expression of miR290-295 cluster in the ESC exosomes compared to MEF exosomes. The underlying beneficial effect of mES Ex was tied to delivery of ESC miR-294 to the heart and in particular CPCs thereby promoting CPC survival and proliferation as analyzed by FACS based cell death analysis and CyQuant assay respectively. Interestingly, enhanced G1/S transition was observed in CPCs treated with miR-294 in conjunction with significant reduction of G1 phase. Conclusion: In conclusion, mES Ex provide a novel cell free system for cardiac regeneration with the ability to modulate both cardiomyocyte and CPC based repair programs in the heart thereby avoiding the risk of teratoma formation associated with ESCs.

scholarly journals The Winding Road of Cardiac Regeneration—Stem Cell Omics in the Spotlight

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 255 ◽  
Author(s):  
Miruna Mihaela Micheu ◽  
Alina Ioana Scarlatescu ◽  
Alexandru Scafa-Udriste ◽  
Maria Dorobantu
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Fate ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Unmet Need ◽  
Cardiac Regeneration ◽  
Cell Types ◽  
Great Promise ◽  
Omics Data

Despite significant progress in treating ischemic cardiac disease and succeeding heart failure, there is still an unmet need to develop effective therapeutic strategies given the persistent high-mortality rate. Advances in stem cell biology hold great promise for regenerative medicine, particularly for cardiac regeneration. Various cell types have been used both in preclinical and clinical studies to repair the injured heart, either directly or indirectly. Transplanted cells may act in an autocrine and/or paracrine manner to improve the myocyte survival and migration of remote and/or resident stem cells to the site of injury. Still, the molecular mechanisms regulating cardiac protection and repair are poorly understood. Stem cell fate is directed by multifaceted interactions between genetic, epigenetic, transcriptional, and post-transcriptional mechanisms. Decoding stem cells’ “panomic” data would provide a comprehensive picture of the underlying mechanisms, resulting in patient-tailored therapy. This review offers a critical analysis of omics data in relation to stem cell survival and differentiation. Additionally, the emerging role of stem cell-derived exosomes as “cell-free” therapy is debated. Last but not least, we discuss the challenges to retrieve and analyze the huge amount of publicly available omics data.

Abstract 35: Enhanced Reprogramming of Human Fibroblasts into Cardiomyocytes Using Minimal Transcription Factors

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Yang Zhou ◽  
Sahar Alimohamadi ◽  
Jiandong Liu ◽  
Li Qian
Keyword(s):  
Transcription Factors ◽  
Disease Modeling ◽  
Human Fibroblasts ◽  
Cardiac Injury ◽  
Cardiac Regeneration ◽  
Clinical Applications ◽  
Significant Advance ◽  
Great Promise ◽  
Primary Fibroblasts ◽  
Core Components

The adult human heart has limited regenerative capacity and is thus an important target for novel regenerative approaches to replenish lost cardiomyocytes after cardiac injury. Cardiac reprogramming that converts fibroblasts to contractile induced cardiomyocytes (iCMs) by overexpressing cardiac lineage specific transcription factors holds great promise as an alternative approach for cardiac regeneration and disease modeling. Significant advance has been made to generate mouse iCMs; however, human iCM (hiCM) generation remains challenging and the yield is low for clinical applications. Here, we leveraged the knowledge that we learned from studying mouse iCM reprogramming to define the optimal condition for hiCM induction. We titrated the dosage of the human reprogramming factors systematically and surprisingly found the minimal core components GATA4, MEF2C and TBX5 were sufficient to induce cardiac fate in human primary fibroblasts. This is in sharp contrast to what has been reported in the literature. Subsequently, we cloned these three factors into a polycistronic vector separated by 2A peptides for defined ratio of protein expression. By optimizing the growth condition, we further improved the efficiency of hiCM reprogramming. Mechanistically, we found the balanced expression of this minimal combination of transcription factors with tailored microenvironment enhanced the establishment of cardiac program in non-myocytes. In sum, our study demonstrates that the use of a single vector with only three transcription factors simplifies generation and improves the yield of hiCMs for potential future clinical applications.

scholarly journals Efficient Reverse Genetics Generation of Infectious Junin Viruses Differing in Glycoprotein Processing

2009 ◽  
Vol 83 (11) ◽  
pp. 5606-5614 ◽  
Author(s):  
César G. Albariño ◽  
Éric Bergeron ◽  
Bobbie Rae Erickson ◽  
Marina L. Khristova ◽  
Pierre E. Rollin ◽  
...  
Keyword(s):  
Cleavage Site ◽  
Reverse Genetics ◽  
Case Fatality ◽  
Hemorrhagic Fever ◽  
Wild Type Virus ◽  
Great Promise ◽  
Wild Type ◽  
Efficient System ◽  
Junin Virus ◽  
Junín Virus

ABSTRACT The New World arenaviruses, Junin, Machupo, Guanarito, Sabia, and Chapare, are associated with rapidly progressing severe hemorrhagic fever with a high rate of case fatality in various regions of South America. The threat of natural or deliberate outbreaks associated with these viruses makes the development of preventive or therapeutic measures important. Here we describe a Junin virus functional minigenome system and a reverse genetics system for production of infectious Junin virus. This robust, highly efficient system involves transfection of cells with only two plasmids which transcribe the virus S and L antigenomic RNAs. The utility of the system is demonstrated by generating Junin viruses which encode a glycoprotein precursor (GPC) containing the following: (i) the wild-type (SKI-1/S1P peptidase) cleavage site, (ii) no cleavage site, or (iii) a cleavage site where the SKI-1/S1P motif (RSLK) is replaced by a furin cleavage site (RRKR). In contrast to the wild-type virus, Junin virus lacking a GPC cleavage site replicated within successfully transfected cells but failed to yield infectious virus particles. This confirms observations with other arenaviruses suggesting that GPC cleavage is essential for arenavirus infectivity. In contrast, infectious Junin virus which encoded GPC cleaved by furin-like proteases was easily generated. The two-plasmid, high efficiency aspects of this Junin virus reverse genetics system show great promise for addressing important questions regarding arenavirus hemorrhagic fever disease and for development of precisely attenuated live arenavirus vaccines.

scholarly journals The subterranean catfish Phreatobius cisternarum provides insights into visual adaptations to the phreatic environment

2020 ◽  
Vol 52 ◽  
Author(s):  
Louise N. Perez ◽  
Bertha R. Mariluz ◽  
Jamily Lorena ◽  
Amy Liu ◽  
Marcos P. Sousa ◽  
...  
Keyword(s):  
Hair Cells ◽  
Histological Analysis ◽  
Astyanax Mexicanus ◽  
Sensory Hair Cells ◽  
Light Stimuli ◽  
Sensory Adaptations ◽  
General Organization ◽  
Subterranean Environment ◽  
Shed Light ◽  
Sensory Mechanisms

Vertebrate eyes share the same general organization, though species have evolved morphological and functional adaptations to diverse environments. Cave-adapted animals are characterized by a variety of features including eye reduction, loss of body pigmentation, and enhanced non-visual sensory systems. Species that live in perpetual darkness have also evolved sensory mechanisms that are independent of light stimuli. The subterranean catfish Phreatobius cisternarum lives in the Amazonian phreatic zone and displays a diversity of morphological features that are similar to those observed in cavefish and appear to be adaptations to life in the dark. Here we combine histological and transcriptome analyses to characterize sensory adaptations of P. cisternarum to the subterranean environment. Histological analysis showed that the vestigial eyes of P. cisternarum contain a rudimentary lens. Transcriptome analysis revealed a repertoire of eleven visual and non-visual opsins and the expression of 36 genes involved in lens development and maintenance. In contrast to other cavefish species, such as Astyanax mexicanus, Phreatichthys andruzzii, Sinocyclocheilus anophthalmus and Sinocyclocheilus microphthalmus, DASPEI neuromast staining patterns did not show an increase in the number of sensory hair cells. Our work reveals unique adaptations in the visual system of P. cisternarum to underground habitats and helps to shed light into troglomorphic attributes of subterranean animals.

scholarly journals Arrival or Transient Spaces? Differentiated Politics of Mobilities, Socio-Technological Orderings and Migrants’ Socio-Spatial Embeddedness

2020 ◽  
Vol 5 (3) ◽  
pp. 33-43
Author(s):  
Tabea Bork-Hüffer ◽  
Simon Alexander Peth
Keyword(s):  
Differential Inclusion ◽  
Migrant Workers ◽  
Comparative Approach ◽  
Combined Effects ◽  
Migration Process ◽  
Four Dimensions ◽  
Migration Management ◽  
Highly Skilled Migrants ◽  
Lively Debate ◽  
Shed Light

<p>For the last decade there has been a lively debate on urban arrival spaces. Saunders’ (2011) widely received book <em>Arrival Cities</em> can be seen as catalyst of this debate. Taking a hitherto largely unexplored comparative approach, based on two empirical research studies on migrant workers and highly-skilled migrants in Singapore, this study debates the notion of arrival cities and spaces and argues for a differentiated perspective on the complex and interdependent processes of spatially and socially arriving. By comparing how the politics of mobilities, migration management and differential inclusion influence the migration trajectories of workers and professionals we argue that the concept of transient spaces might be a more fruitful approach for understanding the differentiated processes of arriving and (not) becoming socio-spatially embedded. In order to educe the relevance of a processual perspective, and for a systematic comparison, we apply four analytical dimensions that shed light on the process of migrating, arriving, and passing through. These four dimensions comprise (1) arriving, (2) settling, (3) mingling locally and translocally, and (4) planning ahead for future mobilities. We argue that the scholarship on politics of mobilities needs to take note of the combined effects of states’ and companies’ neoliberal politics of mobility throughout the migration process, and of the increasing relevance of socio-technological orderings, which imprint migrants’ socio-spatial embedding.</p>

scholarly journals Follistatin-like 1 in Cardiovascular Disease and Inflammation

2019 ◽  
Vol 19 (16) ◽  
pp. 1379-1389 ◽  
Author(s):  
Marijn M.C. Peters ◽  
Timion A. Meijs ◽  
Wouter Gathier ◽  
Pieter A.M. Doevendans ◽  
Joost P.G. Sluijter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiovascular Disease ◽  
Posttranslational Modifications ◽  
Cardiac Regeneration ◽  
Regenerative Therapy ◽  
Coronary Syndrome ◽  
Disease Mechanisms ◽  
Spatiotemporal Regulation ◽  
Shed Light

: Follistatin-like 1 (FSTL1), a secreted glycoprotein, has been shown to participate in regulating developmental processes and to be involved in states of disease and injury. Spatiotemporal regulation and posttranslational modifications contribute to its specific functions and make it an intriguing candidate to study disease mechanisms and potentially develop new therapies. With cardiovascular diseases as the primary cause of death worldwide, clarification of mechanisms underlying cardiac regeneration and revascularization remains essential. Recent findings on FSTL1 in both acute coronary syndrome and heart failure emphasize its potential as a target for cardiac regenerative therapy. With this review, we aim to shed light on the role of FSTL1 specifically in cardiovascular disease and inflammation.

scholarly journals Behaviour, biology, and evolution of vocal learning in bats

2019 ◽  
Author(s):  
Sonja C. Vernes ◽  
Gerald S. Wilkinson
Keyword(s):  
Vocal Tract ◽  
Current Knowledge ◽  
Vocal Learning ◽  
Comparative Approach ◽  
Current State ◽  
Evolution Of Speech ◽  
Multiple Levels ◽  
Insight Into ◽  
Shed Light ◽  
Key Questions

SummaryThe comparative approach can provide insight into the evolution of human speech, language, and social communication by studying relevant traits in animal systems. Bats are emerging as a model system with great potential to shed light on these processes given their learned vocalisations, close social interactions, and mammalian brains and physiology. A recent framework outlined the multiple levels of investigation needed to understand vocal learning across a broad range of non-human species including cetaceans, pinnipeds, elephants, birds and bats. Herein we apply this framework to the current state of the art in bat research. This encompasses our understanding of the abilities bats have displayed for vocal learning, what is known about the timing and social structure needed for such learning, and current knowledge about the prevalence of the trait across the order. It also addresses the biology (vocal tract morphology, neurobiology, and genetics) and phylogenetics of this trait. We conclude by highlighting some key questions that should be answered to advance our understanding of the biological encoding and evolution of speech and spoken communication.

scholarly journals At least seven distinct rotavirus genotype constellations in bats with evidence of reassortment and zoonotic transmissions

2020 ◽  
Author(s):  
Ceren Simsek ◽  
Victor Max Corman ◽  
Hermann Ulrich Everling ◽  
Alexander N. Lukashev ◽  
Andrea Rasche ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Reverse Genetics ◽  
Diarrheal Disease ◽  
Rapid Identification ◽  
Viral Metagenomics ◽  
Current Effort ◽  
Viral Pathogens ◽  
Rotavirus A ◽  
Reference Strains ◽  
Shed Light

ABSTRACTBats host many viruses pathogenic to humans, and increasing evidence suggests that Rotavirus A (RVA) also belongs to this list. Rotaviruses cause diarrheal disease in many mammals and birds, and their segmented genomes allow them to reassort and increase their genetic diversity. Eighteen out of 2,142 bat fecal samples (0.8%) collected from Europe, Central America and Africa were PCR-positive for RVA and 11 of those were fully characterized using viral metagenomics. Upon contrasting their genomes with publicly available data, at least 7 distinct bat RVA genotype constellations (GCs) were identified, including evidence of reassortments and 6 novel genotypes. Some of these constellations are spread across the world, whereas others appear to be geographically restricted. Our analyses also suggest that several unusual human and equine RVA strains might be of bat RVA origin, based on their phylogenetic clustering, despite varying levels of nucleotide sequence identities between them. Although SA11 is one of the most widely used reference strains for RVA research and forms the backbone of a reverse genetics system, its origin remained enigmatic. Remarkably, the majority of the genotypes of SA11-like strains were shared with Gabonese bat RVAs, suggesting a potential common origin. Overall, our findings suggest an underexplored genetic diversity of RVAs in bats, which is likely only the tip of the iceberg. Increasing contact between humans and bat wildlife will further increase the zoonosis risk, which warrants closer attention to these viruses.ImportanceThe increased research on bat coronaviruses after SARS-CoV and MERS-CoVallowed the very rapid identification of SARS-CoV-2. This is an excellent example of the importance of knowing viruses harbored by wildlife in general and bats in particular, for global preparedness against emerging viral pathogens. The current effort to characterize bat rotavirus strains from 3 continents shed light on the vast genetic diversity of rotaviruses and also hinted at a bat origin for several atypical rotaviruses in humans and animals, implying that zoonoses of bat rotaviruses might occur more frequently than currently realized.

scholarly journals Recombinant Rotaviruses Rescued by Reverse Genetics Reveal the Role of NSP5 Hyperphosphorylation in the Assembly of Viral Factories

2019 ◽  
Vol 94 (1) ◽  
Author(s):  
Guido Papa ◽  
Luca Venditti ◽  
Francesca Arnoldi ◽  
Elisabeth M. Schraner ◽  
Christiaan Potgieter ◽  
...  
Keyword(s):  
Cell Line ◽  
Posttranslational Modification ◽  
Reverse Genetics ◽  
Nonstructural Protein ◽  
Pivotal Role ◽  
System A ◽  
Phosphorylation Cascade ◽  
Cytoplasmic Structures ◽  
Shed Light

ABSTRACT Rotavirus (RV) replicates in round-shaped cytoplasmic viral factories, although how they assemble remains unknown. During RV infection, NSP5 undergoes hyperphosphorylation, which is primed by the phosphorylation of a single serine residue. The role of this posttranslational modification in the formation of viroplasms and its impact on virus replication remain obscure. Here, we investigated the role of NSP5 during RV infection by taking advantage of a modified fully tractable reverse-genetics system. A trans-complementing cell line stably producing NSP5 was used to generate and characterize several recombinant rotaviruses (rRVs) with mutations in NSP5. We demonstrate that an rRV lacking NSP5 was completely unable to assemble viroplasms and to replicate, confirming its pivotal role in rotavirus replication. A number of mutants with impaired NSP5 phosphorylation were generated to further interrogate the function of this posttranslational modification in the assembly of replication-competent viroplasms. We showed that the rRV mutant strains exhibited impaired viral replication and the ability to assemble round-shaped viroplasms in MA104 cells. Furthermore, we investigated the mechanism of NSP5 hyperphosphorylation during RV infection using NSP5 phosphorylation-negative rRV strains, as well as MA104-derived stable transfectant cell lines expressing either wild-type NSP5 or selected NSP5 deletion mutants. Our results indicate that NSP5 hyperphosphorylation is a crucial step for the assembly of round-shaped viroplasms, highlighting the key role of the C-terminal tail of NSP5 in the formation of replication-competent viral factories. Such a complex NSP5 phosphorylation cascade may serve as a paradigm for the assembly of functional viral factories in other RNA viruses. IMPORTANCE The rotavirus (RV) double-stranded RNA genome is replicated and packaged into virus progeny in cytoplasmic structures termed viroplasms. The nonstructural protein NSP5, which undergoes a complex hyperphosphorylation process during RV infection, is required for the formation of these virus-induced organelles. However, its roles in viroplasm formation and RV replication have never been directly assessed due to the lack of a fully tractable reverse-genetics (RG) system for rotaviruses. Here, we show a novel application of a recently developed RG system by establishing a stable trans-complementing NSP5-producing cell line required to rescue rotaviruses with mutations in NSP5. This approach allowed us to provide the first direct evidence of the pivotal role of this protein during RV replication. Furthermore, using recombinant RV mutants, we shed light on the molecular mechanism of NSP5 hyperphosphorylation during infection and its involvement in the assembly and maturation of replication-competent viroplasms.

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