Neuron Navigator 3 (NAV3) is Required for Heart Development in Zebrafish

Author(s):  
Feng Lv ◽  
Xiaojuan Ge ◽  
Peipei Qian ◽  
Xiaofeng Lu ◽  
Dong Liu ◽  
...  

Abstract As a tightly controlled biological process, cardiogenesis requires the specification and migration of a suite of cell types to form a particular three-dimensional configuration of the heart. Many genetic factors are involved in the formation and maturation of the heart, and any genetic mutations may result in severe cardiac failures. The neuron navigator (NAV) family consists of three vertebrate homologs (NAV1, NAV2, and NAV3) of the neural guidance molecule Uncoordinated-53 (UNC-53) in Caenorhabditis elegans. Although they are recognized as neural regulators, their expressions are also detected in many organs, including the heart, kidney, and liver. However, the functions of NAVs, regardless of neural guidance, remain largely unexplored. In our study, we found that nav3 gene was expressed in the cardiac region of zebrafish embryos from 24 to 48 hours post-fertilization (hpf) by means of in situ hybridization (ISH) assay. A CRISPR/Cas9-based genome editing method was utilized to delete the nav3 gene in zebrafish and loss-of-function of Nav3 resulted in a severe deficiency in its cardiac morphology and structure. The similar phenotypic defects of the knockout mutants could recur by nav3 morpholino injection and be rescued by nav3 mRNA injection. Dual-color fluorescence imaging of ventricle and atrium markers further confirmed the disruption of the heart development in nav3-deleted mutants. Although the heart rate was not affected by the deletion of nav3, the heartbeat intensity was decreased in the mutants. All these findings indicate that Nav3 was required for cardiogenesis in developing zebrafish embryos.

2021 ◽  
Author(s):  
Feng Lv ◽  
Fang Yuan ◽  
Xiaofeng Lu ◽  
Xiaojuan Ge ◽  
Linsheng Shi ◽  
...  

Abstract Background: As a tightly controlled biological process, cardiogenesis requires the specification and migration of a suite of cell types to form a particular three-dimensional configuration of the heart. Many genetic factors are involved in the formation and maturation of the heart, and any genetic mutations may result in severe cardiac failures. The neuron navigator (NAV) family consists of three vertebrate homologs (NAV1, NAV2, and NAV3) of the neural guidance molecule Uncoordinated-53 (UNC-53) in Caenorhabditis elegans. Although they are recognized as neural regulators, their expressions are also detected in many organs, including the heart, kidney, and liver. However, the functions of NAVs, regardless of neural guidance, remain largely unexplored. In this study, we aim to investigate the role of NAV3 in heart development.Results: The nav3 gene was found to be expressed in the cardiac region of zebrafish embryos from 24 to 48 hours post-fertilization (hpf) by means of in situ hybridization (ISH) assay. A CRISPR/Cas9-based genome editing method was utilized to delete the nav3 gene in zebrafish and loss-of-function of Nav3 resulted in a severe deficiency in its cardiac morphology and structure. The similar phenotypic defects of the knockout mutants could recur by nav3 morpholino injection and be rescued by nav3 mRNA injection. Dual-color fluorescence imaging of ventricle and atrium markers further confirmed the disruption of the heart development in nav3-deleted mutants. Although the heart rate was not affected by the deletion of nav3, the heartbeat intensity was decreased in the mutants. Conclusions: The nav3 gene can be expressed in a variety of tissues or organs although it is initially identified as a neural guiding factor. Gene knockout of nav3 in zebrafish leads to severe development malformation of the heart. Moreover, the defective heart development can be rescued by nav3 mRNA injection. All these findings indicate that Nav3 was required for cardiogenesis in the development of zebrafish embryos.


Development ◽  
2021 ◽  
Vol 148 (16) ◽  
Author(s):  
Pablo Hofbauer ◽  
Stefan M. Jahnel ◽  
Sasha Mendjan

ABSTRACT Cardiac congenital disabilities are the most common organ malformations, but we still do not understand how they arise in the human embryo. Moreover, although cardiovascular disease is the most common cause of death globally, the development of new therapies is lagging compared with other fields. One major bottleneck hindering progress is the lack of self-organizing human cardiac models that recapitulate key aspects of human heart development, physiology and disease. Current in vitro cardiac three-dimensional systems are either engineered constructs or spherical aggregates of cardiomyocytes and other cell types. Although tissue engineering enables the modeling of some electro-mechanical properties, it falls short of mimicking heart development, morphogenetic defects and many clinically relevant aspects of cardiomyopathies. Here, we review different approaches and recent efforts to overcome these challenges in the field using a new generation of self-organizing embryonic and cardiac organoids.


2015 ◽  
Vol 396 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Yvonne Schmidt ◽  
Filip Simunovic ◽  
Sandra Strassburg ◽  
Dietmar Pfeifer ◽  
G. Björn Stark ◽  
...  

Abstract Adequate vascularization is an essential requirement for bone development, fracture healing and bone tissue engineering. We have previously described the coculture of primary human osteoblasts (hOBs) and human endothelial cells (HUVECs), designed to investigate the interactions between these cells. In this system, we showed that cocultivation of these two cell types leads to a downregulation of platelet-derived growth factor receptor-α (PDGFR-α) in hOBs, which was a consequence of reduced mRNA stability. In the current study we investigated the possible involvement of microRNAs in this process. Firstly, we performed a microarray analysis of osteoblastic miRNAs following cocultivation with HUVECs, revealing an upregulation of miR-126. This result was confirmed by RT-qPCR, and we observed that the increase is dependent on direct cell-to-cell contacts. Gain-of-function and loss-of-function experiments showed that miR-126 is a negative regulator of PDGFR-α mRNA. Additionally, migration of hOBs was inhibited by miR-126 overexpression and stimulated by miR-126 inhibition. Addition of PDGFR-α blocking antibody to hOB culture also inhibited hOB migration. There was no effect of miR-126 modulation on osteoblast proliferation, apoptosis rate or differentiation. In conclusion, we report that the miR-126/PDGFR-α system regulates the migratory behavior of human osteoblasts, without exerting effects on cell survival and differentiation.


Author(s):  
Waykin Nopanitaya ◽  
Joe W. Grisham ◽  
Johnny L. Carson

An interesting feature of the goldfish liver is the morphology of the hepatic plate, which is always formed by a two-cell layer of hepatocytes. Hepatic plates of the goldfish liver contain an infrequently seen second type of cell, in the centers of plates between two hepatocytes. A TEH study by Yamamoto (1) demonstrated ultrastructural differences between hepatocytes and centrally located cells in hepatic plates; the latter were classified as ductule cells of the biliary system. None of the previous studies clearly showed a three-dimensional organization of the two cell types described. In the present investigation we utilize SEM to elucidate the arrangement of hepatocytes and bile ductular cells in intralobular plates of goldfish liver.Livers from young goldfish (Carassius auratus), about 6-10 cm, fed commercial fish food were used for this study. Hepatic samples were fixed in 4% buffered paraformaldehyde, cut into pieces, fractured, osmicated, CPD, mounted Au-Pd coated, and viewed by SEM at 17-20 kV. Our observations were confined to the ultrastructure of biliary passages within intralobular plates, ductule cells, and hepatocytes.


2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Na Wu ◽  
Chengying Li ◽  
Bin Xu ◽  
Ying Xiang ◽  
Xiaoyue Jia ◽  
...  

Abstract Background Circular RNA (circRNA) have been reported to play important roles in cardiovascular diseases including myocardial infarction and heart failure. However, the role of circRNA in atrial fibrillation (AF) has rarely been investigated. We recently found a circRNA hsa_circ_0099734 was significantly differentially expressed in the AF patients atrial tissues compared to paired control. We aim to investigate the functional role and molecular mechanisms of mmu_circ_0005019 which is the homologous circRNA in mice of hsa_circ_0099734 in AF. Methods In order to investigate the effect of mmu_circ_0005019 on the proliferation, migration, differentiation into myofibroblasts and expression of collagen of cardiac fibroblasts, and the effect of mmu_circ_0005019 on the apoptosis and expression of Ito, INA and SK3 of cardiomyocytes, gain- and loss-of-function of cell models were established in mice cardiac fibroblasts and HL-1 atrial myocytes. Dual-luciferase reporter assays and RIP were performed to verify the binding effects between mmu_circ_0005019 and its target microRNA (miRNA). Results In cardiac fibroblasts, mmu_circ_0005019 showed inhibitory effects on cell proliferation and migration. In cardiomyocytes, overexpression of mmu_circ_0005019 promoted Kcnd1, Scn5a and Kcnn3 expression. Knockdown of mmu_circ_0005019 inhibited the expression of Kcnd1, Kcnd3, Scn5a and Kcnn3. Mechanistically, mmu_circ_0005019 exerted biological functions by acting as a miR-499-5p sponge to regulate the expression of its target gene Kcnn3. Conclusions Our findings highlight mmu_circ_0005019 played a protective role in AF development and might serve as an attractive candidate target for AF treatment.


Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.


Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 771-790 ◽  
Author(s):  
D G Morton ◽  
J M Roos ◽  
K J Kemphues

Abstract Specification of some cell fates in the early Caenorhabditis elegans embryo is mediated by cytoplasmic localization under control of the maternal genome. Using nine newly isolated mutations, and two existing mutations, we have analyzed the role of the maternally expressed gene par-4 in cytoplasmic localization. We recovered seven new par-4 alleles in screens for maternal effect lethal mutations that result in failure to differentiate intestinal cells. Two additional par-4 mutations were identified in noncomplementation screens using strains with a high frequency of transposon mobility. All 11 mutations cause defects early in development of embryos produced by homozygous mutant mothers. Analysis with a deficiency in the region indicates that it33 is a strong loss-of-function mutation. par-4(it33) terminal stage embryos contain many cells, but show no morphogenesis, and are lacking intestinal cells. Temperature shifts with the it57ts allele suggest that the critical period for both intestinal differentiation and embryo viability begins during oogenesis, about 1.5 hr before fertilization, and ends before the four-cell stage. We propose that the primary function of the par-4 gene is to act as part of a maternally encoded system for cytoplasmic localization in the first cell cycle, with par-4 playing a particularly important role in the determination of intestine. Analysis of a par-4; par-2 double mutant suggests that par-4 and par-2 gene products interact in this system.


2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Donghong Zhang ◽  
Jinfeng Ning ◽  
Imoh Okon ◽  
Xiaoxu Zheng ◽  
Ganesh Satyanarayana ◽  
...  

AbstractOncogenic KRAS mutations combined with the loss of the LKB1 tumor-suppressor gene (KL) are strongly associated with aggressive forms of lung cancer. N6-methyladenosine (m6A) in mRNA is a crucial epigenetic modification that controls cancer self-renewal and progression. However, the regulation and role of m6A modification in this cancer are unclear. We found that decreased m6A levels correlated with the disease progression and poor survival for KL patients. The correlation was mediated by a special increase in ALKBH5 (AlkB family member 5) levels, an m6A demethylase. ALKBH5 gain- or loss-of function could effectively reverse LKB1 regulated cell proliferation, colony formation, and migration of KRAS-mutated lung cancer cells. Mechanistically, LKB1 loss upregulated ALKBH5 expression by DNA hypermethylation of the CTCF-binding motif on the ALKBH5 promoter, which inhibited CTCF binding but enhanced histone modifications, including H3K4me3, H3K9ac, and H3K27ac. This effect could successfully be rescued by LKB1 expression. ALKBH5 demethylation of m6A stabilized oncogenic drivers, such as SOX2, SMAD7, and MYC, through a pathway dependent on YTHDF2, an m6A reader protein. The above findings were confirmed in clinical KRAS-mutated lung cancer patients. We conclude that loss of LKB1 promotes ALKBH5 transcription by a DNA methylation mechanism, reduces m6A modification, and increases the stability of m6A target oncogenes, thus contributing to aggressive phenotypes of KRAS-mutated lung cancer.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1445
Author(s):  
Taisa Nogueira Pansani ◽  
Thanh Huyen Phan ◽  
Qingyu Lei ◽  
Alexey Kondyurin ◽  
Bill Kalionis ◽  
...  

Extracellular vesicles (EVs) are nanoparticles released by cells that contain a multitude of biomolecules, which act synergistically to signal multiple cell types. EVs are ideal candidates for promoting tissue growth and regeneration. The tissue regenerative potential of EVs raises the tantalizing possibility that immobilizing EVs on implant surfaces could potentially generate highly bioactive and cell-instructive surfaces that would enhance implant integration into the body. Such surfaces could address a critical limitation of current implants, which do not promote bone tissue formation or bond bone. Here, we developed bioactive titanium surface coatings (SurfEV) using two types of EVs: secreted by decidual mesenchymal stem cells (DEVs) and isolated from fermented papaya fluid (PEVs). For each EV type, we determined the size, morphology, and molecular composition. High concentrations of DEVs enhanced cell proliferation, wound closure, and migration distance of osteoblasts. In contrast, the cell proliferation and wound closure decreased with increasing concentration of PEVs. DEVs enhanced Ca/P deposition on the titanium surface, which suggests improvement in bone bonding ability of the implant (i.e., osteointegration). EVs also increased production of Ca and P by osteoblasts and promoted the deposition of mineral phase, which suggests EVs play key roles in cell mineralization. We also found that DEVs stimulated the secretion of secondary EVs observed by the presence of protruding structures on the cell membrane. We concluded that, by functionalizing implant surfaces with specialized EVs, we will be able to enhance implant osteointegration by improving hydroxyapatite formation directly at the surface and potentially circumvent aseptic loosening of implants.


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