Giant Retinal Astrocytoma: A Case Report of an Uncommon Presentation of Tuberous Sclerosis in a Young Female.

Tuberous sclerosis (TS) is a rare multisystem autosomal dominant genetic disorder with characteristic pathognomonic genetic mutations involving the TSC (tuberous sclerosis complex) group of genes. Ocular signs are fairly common and include an achromic patch and retinal astrocytic hamartomas, which usually have a maximum size of between 0.5 and 5 mm. The incidence of tuberous sclerosis is estimated to be 1 in 5000-10,000 individuals, with both familial and sporadic cases reported. The diagnostic criteria for tuberous sclerosis include the presence of major and/or minor clinical features as well as genetic mutations. We present the case of a 15-year-old girl, presented with a history of seizures and blurred vision. Physical examination revealed angiofibroma on the face. Further evaluation, including contrast-enhanced MRI of the brain and ophthalmological consultation, led to the diagnosis of tuberous sclerosis. Additional imaging studies confirmed the presence of subependymal giant cell astrocytoma, retinal astrocytoma, lymphangioleiomyomatosis in the lungs, and renal angiomyolipoma. This case highlights the importance of considering tuberous sclerosis in patients presenting with seizures and ocular symptoms. This case sheds light on early diagnosis and appropriate management which are crucial in preventing complications and improving patient outcomes.

Metabolic Syndrome Frequency in Type 2 Diabetics Using International Diabetes Federation (IDF) Criteria Analysis.

Background The cluster of metabolic abnormalities known as metabolic syndrome has a significant association with the onset of type 2 diabetes mellitus (T2DM) and cardiovascular disease. The objective of this study was to evaluate the occurrence rate of metabolic syndrome among a group of patients diagnosed with T2DM, according to the standards set by the International Diabetes Federation (IDF). Methodology A descriptive cross-sectional study was conducted at Chandka Medical College, Larkana, Pakistan, from June 2019 to 2020. Using the IDF criteria for metabolic syndrome, 131 type 2 diabetics over age 30 were purposively sampled, excluding specific medical conditions and medications. Trained nurses recorded patient demographics, waist circumference, and blood pressure. Relevant laboratory tests were conducted, and metabolic syndrome prevalence was determined. Data were analyzed using IBM SPSS Statistics for Windows, Version 19, (Released 2010; IBM Corp., Armonk, New York, United States), considering both quantitative and qualitative variables. Results The research found that the occurrence of metabolic syndrome was 87.2%. It is worth mentioning that age did not have a considerable connection with metabolic syndrome incidence (p=0.873), as the overwhelming majority of participants in both groups were aged over 40 years. However, there was a clear link (p=0.001) between gender and the 'no metabolic syndrome' group, with more males in this category. Additionally, blood pressure was significantly linked to metabolic syndrome (p=0.001), with most individuals having normal blood pressure in the 'no metabolic syndrome' group. Although serum triglyceride levels were not significantly associated with metabolic syndrome (p=0.222), serum HDL cholesterol levels had a significant relationship (p<0.0001), where most people possessed HDL levels ≥40mg/dl in the 'no metabolic syndrome' category. Conclusion The findings of this investigation demonstrated a substantial occurrence of metabolic syndrome in patients with T2DM, wherein notable links were detected with gender, blood pressure, and HDL cholesterol levels. However, no significant correlation was observed with age or serum triglycerides. These results emphasize the necessity for an all-inclusive metabolic care approach for individuals with T2DM.

A qualitative evaluation of the impact of a medical student school outreach project on both medical students and school pupils.

OBJECTIVE: To explore medical student and school pupil experiences of an outreach school teaching project. SETTING: Community engagement is increasingly commonplace within medical school. Secondary schools offer ample opportunities for community engagement as medical students teach and engage in service learning. There is a lack of research regarding the impact of school community engagement projects and the impact on pupils, as critical stakeholders in the service medical students provide. In this qualitative study, we explore the perspectives of medical students and school pupils involved in a school teaching project. PARTICIPANTS: Ten medical students participated in individual interviews, and 17 school pupils across three schools participated in group interviews. Data were analysed using thematic analysis and the concept of service learning. RESULTS: For medical students, the project fostered communication and teaching skills, but a lack of reflection hampered further benefit. For school pupils, experiences varied - learning about careers in medicine could be inspiring, but content pitched at the incorrect level disengaged some pupils. The conflict between session timing and medical students' exams negatively influenced engagement. CONCLUSIONS: To shift the focus of community engagement projects that promote service-learning towards mutual benefit, designing in partnership with relevant community stakeholders and integrating opportunities to reflect on these experiences are critical.

Cardiovascular Complications of Diabetes: From Microvascular to Macrovascular Pathways.

Diabetes mellitus, with a growing risk of developing complications, has a significant negative impact on cardiovascular health, including microvascular and macrovascular issues. This thorough narrative study methodically examines the complex connection between cardiovascular problems and diabetes. We start by thoroughly introducing diabetes mellitus, classifying its various forms, and discussing its growing global impact. Then, we examine retinopathy, nephropathy, and neuropathy in detail, illuminating their biology, clinical presentations, and treatment options. Moving on to macrovascular consequences, we investigate the complex relationships between diabetes and coronary artery disease, stroke, and peripheral arterial disease, emphasizing risk factors, diagnostic standards, and treatment plans designed for people with diabetes. The review analyzes the pathophysiological pathways that link diabetes to cardiovascular problems, including endothelial dysfunction, chronic inflammation, immune system dysregulation, and oxidative stress brought on by hyperglycemia. Additionally, we review the critical function of risk monitoring, assessment, and predictive tools in early detection. While highlighting current research paths and the need for tailored medical approaches to address this complex health issue, the story also includes prevention and management strategies, ranging from lifestyle changes to developing medications. This narrative review concludes by providing a thorough summary of current information, highlighting research gaps, and advocating for interdisciplinary efforts to reduce the cardiovascular effects of diabetes.

Learning machines or the key to care: a qualitative study exploring the impact of the hidden curriculum on medical students' longitudinal experiences in primary care.

OBJECTIVE: Longitudinal learning often faces implementation challenges within UK medical schools. Some have suggested that the hidden curriculum may be implicated, but there is little evidence regarding how the hidden curriculum influences student experiences of, and engagement with longitudinal learning. Given this, our objective was to explore the impact of the hidden curriculum on student experiences of a longitudinal curriculum based in primary care at a research-intensive medical school. DESIGN: We conducted a longitudinal qualitative study. Students participated in three serial, in-depth semistructured interviews. We conducted a longitudinal thematic analysis. SETTING: One research-intensive medical school based in the UK. Data collection occurred in 2021-2022. PARTICIPANTS: 12 penultimate year medical students taking part in a longitudinal primary care placement for 1 day a week over the course of one academic year. RESULTS: We constructed four themes capturing insights on how hidden curricula influenced students' experiences: (1) A culture which stresses assessment influences student engagement with longitudinal learning; (2) Longitudinal relationships can challenge the hidden curriculum; (3) Support and continuity within primary care improves skills and can influence belonging and (4) Logistical issues influence engagement with longitudinal learning. CONCLUSIONS: The hidden curriculum, particularly related to assessment, plays a large role in student perceptions of educational value and subsequent engagement with curricula. In a research-intensive institution, longitudinal learning, particularly within primary care, was perceived as at odds with what was important for assessments. Where longitudinal relationships were successfully established, students became more aware of the benefits of person-centred practice. For primary care longitudinal education to succeed in more research-intensive institutions, there must first be advocacy for greater representation of primary care and person-centred values within organisational structures to ensure meaningful curricular alignment.

Building partnerships with local schools.

BACKGROUND: Medical schools have a responsibility to support their students in developing an understanding of the complex concepts of a 'VUCA' (volatile, uncertain, complex and ambiguous) world. To achieve this, service learning approaches have been increasingly successfully employed for students to learn through participating in activities addressing local community priorities. Sharing outcomes and lessons from such programmes is essential for advancing service learning. We present the evaluation of a new service learning module co-designed at Imperial College London with local schools and wider stakeholders. APPROACH: Students partnered with local schoolteachers to design and implement inclusive science-based after-school sessions for secondary school pupils. The module aimed to foster critical reflection on social accountability, power and privilege whilst encouraging aspirations for higher education in school pupils. EVALUATION: Our evaluation draws on the perspectives of stakeholders in the first iteration of the module in 2021. Qualitative data were collected through university student reflections, presentations and debriefs (n = 20); semi-structured interviews with schoolteachers (n = 6); and questionnaires with wider stakeholders (n = 6). The evaluation revealed mutual benefits, as students reflected on their own societal roles, whilst considering the complexities of concepts such as inclusivity, power and privilege. Schoolteachers highlighted students' impact as inspiring role models for pupils, fostering aspirations for higher education. IMPLICATIONS: This module provides a replicable framework for supporting students in developing their reflections on their role in our VUCA world whilst addressing the priorities identified by local schools. The evaluation highlighted the importance of working collaboratively with community stakeholders when embarking on service learning projects.

Rab11 is essential to pancreas morphogenesis, lumen formation and endocrine mass.

The molecular links between tissue-level morphogenesis and the differentiation of cell lineages in the pancreas remain elusive despite a decade of studies. We previously showed that in pancreas both processes depend on proper lumenogenesis. The Rab GTPase Rab11 is essential for epithelial lumen formation in vitro, however few studies have addressed its functions in vivo and none have tested its requirement in pancreas. Here, we show that Rab11 is critical for proper pancreas development. Co-deletion of the Rab11 isoforms Rab11A and Rab11B in the developing pancreatic epithelium (Rab11pancDKO) results in ∼50% neonatal lethality and surviving adult Rab11pancDKO mice exhibit defective endocrine function. Loss of both Rab11A and Rab11B in the embryonic pancreas results in morphogenetic defects of the epithelium, including defective lumen formation and lumen interconnection. In contrast to wildtype cells, Rab11pancDKO cells initiate the formation of multiple ectopic lumens, resulting in a failure to coordinate a single apical membrane initiation site (AMIS) between groups of cells. This results in an inability to form ducts with continuous lumens. Here, we show that these defects are due to failures in vesicle trafficking, as apical and junctional components remain trapped within Rab11pancDKO cells. Together, these observations suggest that Rab11 directly regulates epithelial lumen formation and morphogenesis. Our report links intracellular trafficking to organ morphogenesis in vivo and presents a novel framework for decoding pancreatic development.

Endothelial Cyp26b1 restrains murine heart valve growth during development.

Endothelial cells (ECs) are critical to proper heart valve development, directly contributing to the mesenchyme of the cardiac cushions, which progressively transform into mature valves. To date, investigators have lacked sufficient markers of valve ECs to evaluate their contributions during valve morphogenesis fully. As a result, it has been unclear whether the well-characterized regional differentiation of valves correlates with any endothelial domains in the heart. Furthermore, it has been difficult to ascertain whether endothelial heterogeneity in the heart influences underlying mesenchymal zones in an angiocrine manner. To identify regionally expressed EC genes in the heart valves, we screened publicly available databases and assembled a toolkit of endothelial-enriched genes. We identified Cyp26b1 as one of many endothelial enriched genes found to be expressed in the endocardium of the developing cushions and valves. Here, we show that Cyp26b1 is required for normal heart valve development. Genetic ablation of Cyp26b1 in mouse embryos leads to abnormally thickened aortic valve leaflets, which is due in part to increased endothelial and mesenchymal cell proliferation in the remodeling valves. In addition, Cyp26b1 mutant hearts display ventricular septal defects (VSDs) in a portion of null embryos. We show that loss of Cyp26b1 results in upregulation of retinoic acid (RA) target genes, supporting the observation that Cyp26b1 has RA-dependent roles. Together, this work identifies a novel role for Cyp26b1 in heart valve morphogenesis and points to a role of RA in this process. Understanding the spatiotemporal expression dynamics of cardiac EC genes will pave the way for investigation of both normal and dysfunctional heart valve development.

Improved loss-of-function CRISPR-Cas9 genome editing in human cells concomitant with inhibition of TGF-ß signaling.

Strategies to modulate cellular DNA repair pathways hold immense potential to enhance the efficiency of CRISPR-Cas9 genome editing platform. In the absence of a repair template, CRISPR-Cas9-induced DNA double-strand breaks are repaired by the endogenous cellular DNA repair pathways to generate loss-of-function edits. Here, we describe a reporter-based assay for expeditious measurement of loss-of-function editing by CRISPR-Cas9. An unbiased chemical screen performed using this assay enabled the identification of small molecules that promote loss-of-function editing. Iterative rounds of screens reveal Repsox, a TGF-ß signaling inhibitor, as a CRISPR-Cas9 editing efficiency enhancer. Repsox invariably increased CRISPR-Cas9 editing in a panel of commonly used cell lines in biomedical research and primary cells. Furthermore, Repsox-mediated editing enhancement in primary human CD4+ T cells enabled the generation of HIV-1-resistant cells with high efficiency. This study demonstrates the potential of transiently targeting cellular pathways by small molecules to improve genome editing for research applications and is expected to benefit gene therapy efforts.

Myocardial Afterload Is a Key Biomechanical Regulator of Atrioventricular Myocyte Differentiation in Zebrafish.

Heart valve development is governed by both genetic and biomechanical inputs. Prior work has demonstrated that oscillating shear stress associated with blood flow is required for normal atrioventricular (AV) valve development. Cardiac afterload is defined as the pressure the ventricle must overcome in order to pump blood throughout the circulatory system. In human patients, conditions of high afterload can cause valve pathology. Whether high afterload adversely affects embryonic valve development remains poorly understood. Here we describe a zebrafish model exhibiting increased myocardial afterload, caused by vasopressin, a vasoconstrictive drug. We show that the application of vasopressin reliably produces an increase in afterload without directly acting on cardiac tissue in zebrafish embryos. We have found that increased afterload alters the rate of growth of the cardiac chambers and causes remodeling of cardiomyocytes. Consistent with pathology seen in patients with clinically high afterload, we see defects in both the form and the function of the valve leaflets. Our results suggest that valve defects are due to changes in atrioventricular myocyte signaling, rather than pressure directly acting on the endothelial valve leaflet cells. Cardiac afterload should therefore be considered a biomechanical factor that particularly impacts embryonic valve development.

The cell cortex as mediator of pancreatic epithelial development and endocrine differentiation.

Organogenesis is the complex process of cells coordinating their own proliferation with changes to their shape, cell migration and cell-cell signaling, so that they transform into a three dimensional functional tissue, with its own custom range of differentiated cell types. Understanding when and where critical signals emanate from, and how those signals are transduced and interpreted, is the fundamental challenge of developmental biology. Here, we review recent findings regarding how progenitor cells interpret cues during pancreatic morphogenesis and how they coordinate cell fate determination. Recent evidence suggests that molecules located in the cell cortex play a crticial role in determining cellular behavior during pancreatic morphogenesis. Specifically, we find that control of cell adhesion, polarity, and constriction are all integral to both initiation of epithelial development and to later cell differentiation. Here, we review key molecules that coordinate these processes and suggest that the cell cortex acts as a signaling center that relays cues during pancreas development.

E2F1 and epigenetic modifiers orchestrate breast cancer progression by regulating oxygen-dependent ESRP1 expression.

Epithelial splicing regulatory protein 1 (ESRP1) is an RNA binding protein that governs the alternative splicing events related to epithelial phenotypes. ESRP1 contributes significantly at different stages of cancer progression. ESRP1 expression is substantially elevated in carcinoma in situ compared to the normal epithelium, whereas it is drastically ablated in cancer cells within hypoxic niches, which promotes epithelial to mesenchymal transition (EMT). Although a considerable body of research sought to understand the EMT-associated ESRP1 downregulation, the regulatory mechanisms underlying ESRP1 upregulation in primary tumors remained largely uncharted. This study seeks to unveil the regulatory mechanisms that spatiotemporally fine-tune the ESRP1 expression during breast carcinogenesis. Our results reveal that an elevated expression of transcription factor E2F1 and increased CpG hydroxymethylation of the E2F1 binding motif conjointly induce ESRP1 expression in breast carcinoma. However, E2F1 fails to upregulate ESRP1 despite its abundance in oxygen-deprived breast cancer cells. Mechanistically, impelled by the hypoxia-driven reduction of tet methylcytosine dioxygenase 3 (TET3) activity, CpG sites across the E2F1 binding motif lose the hydroxymethylation marks while gaining the de novo methyltransferase-elicited methylation marks. These two oxygen-sensitive epigenetic events work in concert to repel E2F1 from the ESRP1 promoter, thereby diminishing ESRP1 expression under hypoxia. Furthermore, E2F1 skews the cancer spliceome by upregulating splicing factor SRSF7 in hypoxic breast cancer cells. Our findings provide previously unreported mechanistic insights into the plastic nature of ESRP1 expression and insinuate important implications in therapeutics targeting breast cancer progression.

In Vivo Pressurization of the Zebrafish Embryonic Heart as a Tool to Characterize Tissue Properties During Development.

Cardiac morphogenesis requires an intricate orchestration of mechanical stress to sculpt the heart as it transitions from a straight tube to a multichambered adult heart. Mechanical properties are fundamental to this process, involved in a complex interplay with function, morphology, and mechanotransduction. In the current work, we propose a pressurization technique applied to the zebrafish atrium to quantify mechanical properties of the myocardium under passive tension. By further measuring deformation, we obtain a pressure-stretch relationship that is used to identify constitutive models of the zebrafish embryonic cardiac tissue. Two-dimensional results are compared with a three-dimensional finite element analysis based on reconstructed embryonic heart geometry. Through these steps, we found that the myocardium of zebrafish results in a stiffness on the order of 10 kPa immediately after the looping stage of development. This work enables the ability to determine how these properties change under normal and pathological heart development.

Hypoxia-induced TGF-ß-RBFOX2-ESRP1 axis regulates human MENA alternative splicing and promotes EMT in breast cancer.

Hypoxic microenvironment heralds epithelial-mesenchymal transition (EMT), invasion and metastasis in solid tumors. Deregulation of alternative splicing (AS) of several cancer-associated genes has been instrumental in hypoxia-induced EMT. Our study in breast cancer unveils a previously unreported mechanism underlying hypoxia-mediated AS of hMENA, a crucial cytoskeleton remodeler during EMT. We report that the hypoxia-driven depletion of splicing regulator ESRP1 leads to skipping of hMENA exon 11a producing a pro-metastatic isoform, hMENAΔ11a. The transcriptional repression of ESRP1 is mediated by SLUG, which gets stimulated via hypoxia-driven TGF-ß signaling. Interestingly, RBFOX2, an otherwise RNA-binding protein, is also found to transcriptionally repress ESRP1 while interacting with SLUG. Similar to SLUG, RBFOX2 gets upregulated under hypoxia via TGF-ß signaling. Notably, we found that the exosomal delivery of TGF-ß contributes to the elevation of TGF-ß signaling under hypoxia. Moreover, our results show that in addition to hMENA, hypoxia-induced TGF-ß signaling contributes to global changes in AS of genes associated with EMT. Overall, our findings reveal a new paradigm of hypoxia-driven AS regulation of hMENA and insinuate important implications in therapeutics targeting EMT.

Applying the Eosinophilic Esophagitis Endoscopic Reference Scores (EREFS) to Different Aged Children.

OBJECTIVES: The eosinophilic esophagitis (EoE) endoscopic reference score (EREFS) was developed to analyze adults with EoE and has been successfully applied to a pediatric cohort. The present study compares EREFS in younger and older children with EoE. METHODS: The 99 patients were divided among 3 cohorts: 44 active EoE (EoE-A); 16 EoE remission (EoE-R); and 39 controls (esophageal dysfunction but <15 eos/hpf). The cohorts were then subdivided into 2 groups: younger (≤10 years) and older (>10 years) that were compared based on the composite and the individual components of their EREFS. RESULTS: EREFS identified EoE-A in all children with an area under the receiving operating characteristics curve (AUC) of 0.85, in older children with an AUC of 0.90 and in younger children with an AUC of 0.77. Mean EREFS for ≤10 years was 1.26 ±â€Š1.19 and 2.71 ±â€Š1.33 for >10 years (P < 0.01). The 3 most common findings in our entire EoE-A cohort and in both ages were furrows, edema, and exudates. EREFS in patients with EoE-A had similar specificities (0.88 vs 0.89) and positive predictive values (0.89 vs 0.91) in both ages. CONCLUSIONS: The present investigation confirms the utilization of EREFS in Pediatric EoE. Furthermore, EREFS can detect EoE and document response to treatment in both younger and older children. EREFS, however, predicted EoE in the older children with a higher sensitivity (0.89 vs 0.63) and a higher negative predictive value (0.87 vs 0.59) than was seen in the younger cohort.

Biomechanical Cues Direct Valvulogenesis.

The vertebrate embryonic heart initially forms with two chambers, a ventricle and an atrium, separated by the atrioventricular junction. Localized genetic and biomechanical information guides the development of valves, which function to ensure unidirectional blood flow. If the valve development process goes awry, pathology associated with congenital valve defects can ensue. Congenital valve defects (CVD) are estimated to affect 1-2% of the population and can often require a lifetime of treatment. Despite significant clinical interest, molecular genetic mechanisms that direct valve development remain incompletely elucidated. Cells in the developing valve must contend with a dynamic hemodynamic environment. A growing body of research supports the idea that cells in the valve are highly sensitive to biomechanical forces, which cue changes in gene expression required for normal development or for maintenance of the adult valve. This review will focus on mechanotransductive pathways involved in valve development across model species. We highlight current knowledge regarding how cells sense physical forces associated with blood flow and pressure in the forming heart, and summarize how these changes are transduced into genetic and developmental responses. Lastly, we provide perspectives on how altered biomechanical cues may lead to CVD pathogenesis.

miR-182-5p is an evolutionarily conserved Tbx5 effector that impacts cardiac development and electrical activity in zebrafish.

To dissect the TBX5 regulatory circuit, we focused on microRNAs (miRNAs) that collectively contribute to make TBX5 a pivotal cardiac regulator. We profiled miRNAs in hearts isolated from wild-type, CRE, Tbx5lox/+and Tbx5del/+ mice using a Next Generation Sequencing (NGS) approach. TBX5 deficiency in cardiomyocytes increased the expression of the miR-183 cluster family that is controlled by Kruppel-like factor 4, a transcription factor repressed by TBX5. MiR-182-5p, the most highly expressed miRNA of this family, was functionally analyzed in zebrafish. Transient overexpression of miR-182-5p affected heart morphology, calcium handling and the onset of arrhythmias as detected by ECG tracings. Accordingly, several calcium channel proteins identified as putative miR-182-5p targets were downregulated in miR-182-5p overexpressing hearts. In stable zebrafish transgenic lines, we demonstrated that selective miRNA-182-5p upregulation contributes to arrhythmias. Moreover, cardiac-specific down-regulation of miR-182-5p rescued cardiac defects in a zebrafish model of Holt-Oram syndrome. In conclusion, miR-182-5p exerts an evolutionarily conserved role as a TBX5 effector in the onset of cardiac propensity for arrhythmia, and constitutes a relevant target for mediating the relationship between TBX5, arrhythmia and heart development.

UK longitudinal integrated clerkships: where are we now?

In this article, we discuss whether it is possible for UK institutions to influence the international longitudinal integrated clerkship (LIC) narrative, in the context of supplying future clinicians to a fragmented health service that is battling a General Practice recruitment crisis. Perhaps more importantly, we will discuss whether the 'LIC model' fits the UK undergraduate framework. We intend to present some emerging evidence of LICs in the UK, informed by a UK-wide survey and observations from a 2019 UK LIC think tank and then discuss whether the global CLIC definition applies to the UK context with possible ways forward.

Post-transcriptional Modulation of Sphingosine-1-Phosphate Receptor 1 by miR-19a Affects Cardiovascular Development in Zebrafish.

Sphingosine-1-phosphate is a bioactive lipid and a signaling molecule integrated into many physiological systems such as differentiation, proliferation and migration. In mammals S1P acts through binding to a family of five trans-membrane, G-protein coupled receptors (S1PRs) whose complex role has not been completely elucidated. In this study we use zebrafish, in which seven s1prs have been identified, to investigate the role of s1pr1. In mammals S1PR1 is the most highly expressed S1P receptor in the developing heart and regulates vascular development, but in zebrafish the data concerning its role are contradictory. Here we show that overexpression of zebrafish s1pr1 affects both vascular and cardiac development. Moreover we demonstrate that s1pr1 expression is strongly repressed by miR-19a during the early phases of zebrafish development. In line with this observation and with a recent study showing that miR-19a is downregulated in a zebrafish Holt-Oram model, we now demonstrate that s1pr1 is upregulated in heartstring hearts. Next we investigated whether defects induced by s1pr1 upregulation might contribute to the morphological alterations caused by Tbx5 depletion. We show that downregulation of s1pr1 is able to partially rescue cardiac and fin defects induced by Tbx5 depletion. Taken together, these data support a role for s1pr1 in zebrafish cardiovascular development, suggest the involvement of this receptor in the Tbx5 regulatory circuitry, and further support the crucial role of microRNAs in early phase of zebrafish development.