hace1 Influences zebrafish cardiac development via ROS-dependent mechanisms

Zebrafish as a Model for Investigating Antiviral Innate Immunity

Zebrafish is a widely used model organism in genetics, developmental biology, pathology, and immunology research. Due to their fast reproduction, large numbers, transparent early embryos, and high genetic conservation with the human genome, zebrafish have been used as a model for studying human and fish viral diseases. In particular, the ability to easily perform forward and reverse genetics and lacking a functional adaptive immune response during the early period of development establish the zebrafish as a favored option to assess the functional implication of specific genes in the antiviral innate immune response and the pathogenesis of viral diseases. In this chapter, we detail protocols for the antiviral innate immunity analysis using the zebrafish model, including the generation of gene-overexpression zebrafish, generation of gene-knockout zebrafish by clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technology, methods of viral infection in zebrafish larvae, analyzing the expression of antiviral genes in zebrafish larvae using qRT-PCR, Western blotting and transcriptome sequencing, and in vivo antiviral assays. These experimental protocols provide effective references for studying the antiviral immune response in the zebrafish model.

Flusilazole induced developmental toxicity, neurotoxicity, and cardiovascular toxicity via apoptosis and oxidative stress in zebrafish

Flusilazole is a well-known triazole fungicide applied to various crops and fruits worldwide. Flusilazole residues are frequently detected in the environment, and many researchers have reported the hazardous effects of flusilazole on non-target organisms; however, the developmental toxicity of flusilazole has not been fully elucidated. In this study, we investigated flusilazole-induced developmental defects in zebrafish, which are used in toxicology studies to assess the toxic effects of chemicals on aquatic species or vertebrates. We confirmed that flusilazole exposure affected the viability and hatching rate of zebrafish larvae, and resulted in morphological defects, reduced body length, diminished eye and head sizes, and inflated pericardial edema. Apoptosis, oxidative stress, and inflammation were also observed. These factors interrupted the normal organ formation during early developmental stages, and transgenic models were used to identify organ defects. We confirmed the effects of flusilazole on the nervous system using olig2:dsRed transgenic zebrafish, and on the cardiovascular system using cmlc2:dsRed and fli1:eGFP transgenic zebrafish. Our results demonstrate the developmental toxicity of flusilazole and its mechanisms in zebrafish as well as the detrimental effects of flusilazole.

A nox2/cybb zebrafish mutant with defective myeloid cell reactive oxygen species production displays normal initial neutrophil recruitment to sterile tail injuries

Reactive oxygen species are important effectors and modifiers of the acute inflammatory response, recruiting phagocytes including neutrophils to sites of tissue injury. In turn, phagocytes such as neutrophils are both consumers and producers of reactive oxygen species. Phagocytes including neutrophils generate reactive oxygen species in an oxidative burst through the activity of a multimeric phagocytic nicotinamide adenine dinucleotide phosphate oxidase complex. Mutations in the NOX2/CYBB (previously gp91phox) nicotinamide adenine dinucleotide phosphate oxidase subunit are the commonest cause of chronic granulomatous disease, a disease characterized by infection susceptibility and an inflammatory phenotype. To model chronic granulomatous disease, we made a nox2/cybb zebrafish (Danio rerio) mutant and demonstrated it to have severely impaired myeloid cell reactive oxygen species production. Reduced early survival of nox2 mutant embryos indicated an essential requirement for nox2 during early development. In nox2/cybb zebrafish mutants, the dynamics of initial neutrophil recruitment to both mild and severe surgical tailfin wounds was normal, suggesting that excessive neutrophil recruitment at the initiation of inflammation is not the primary cause of the "sterile" inflammatory phenotype of chronic granulomatous disease patients. This nox2 zebrafish mutant adds to existing in vivo models for studying reactive oxygen species function in myeloid cells including neutrophils in development and disease.

HACE1 expression in heart failure patients might promote mitochondrial oxidative stress and ferroptosis by targeting NRF2

BACKGROUND

Heart failure is a prevalent and life-threatening medical condition characterized by abnormal atrial electrical activity, contributing to a higher risk of ischemic stroke. Atrial remodelling, driven by oxidative stress and structural changes, plays a central role in heart failure progression. Recent studies suggest that HACE1, a regulatory gene, may be involved in cardiac protection against heart failure.

METHODS

Clinical data analysis involved heart failure patients, while an animal model utilized C57BL/6J mice. RT-PCR, microarray analysis, histological examination, ELISA, and Western blot assays were employed to assess gene and protein expression, oxidative stress, and cardiac function. Cell transfection and culture of mouse atrial fibroblasts were performed for in-vitro experiments.

RESULTS

HACE1 expression was reduced in heart failure patients and correlated negatively with collagen levels. In mouse models, HACE1 up-regulation reduced oxidative stress, mitigated fibrosis, and improved cardiac function. Conversely, HACE1 knockdown exacerbated oxidative stress, fibrosis, and cardiac dysfunction. HACE1 also protected against ferroptosis and mitochondrial damage. NRF2, a transcription factor implicated in oxidative stress, was identified as a target of HACE1, with HACE1 promoting NRF2 activity through ubiquitination.

CONCLUSIONS

HACE1 emerges as a potential therapeutic target and diagnostic marker for heart failure. It regulates oxidative stress, mitigates cardiac fibrosis, and protects against ferroptosis and mitochondrial damage. The study reveals that HACE1 achieves these effects, at least in part, through NRF2 activation via ubiquitination, offering insights into novel mechanisms for heart failure pathogenesis and potential interventions.

Hace1 overexpression mitigates myocardial hypoxia/reoxygenation injury via the effects on Keap1/Nrf2 pathway

HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1 (Hace1) is a crucial mediator of multiple pathological disorders. However, there are few studies regarding the role of Hace1 in myocardial ischemia/reperfusion injury. Here, we studied the functional role of Hace1 on myocardial ischemia/reperfusion injury using hypoxia/reoxygenation (H/R)-injured cardiac cells in vitro. Reduced levels of Hace1 were observed in H/R-exposed cardiac cells. Hace1-overexpressed cardiac cells were resistant to H/R injuries with reduced apoptosis, lowered oxidative stress, and a suppressed inflammatory response. Subsequent analysis revealed that Hace1 overexpression enhanced the activation of nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and increased the transcriptional activity of Nrf2 in H/R-exposed cardiac cells. The knockout of kelch-like ECH-associated protein 1 (Keap1) diminished the regulatory role of Hace1 on Nrf2 activation. Additionally, inhibiting Nrf2 reversed Hace1-elicited cardioprotective effects in H/R-injured cardiac cells. In short, these data demonstrated that Hace1 overexpression mitigated myocardial H/R injury by enhancing the Nrf2 pathway via Keap1. This work underlines a possible role of Hace1 in myocardial ischemia/reperfusion injury and suggests Hace1 as a candidate target for exploiting cardioprotective therapy.

High-throughput transcriptome sequencing reveals the key stages of cardiovascular development in zebrafish embryos

BACKGROUND

The cardiovascular developmental process is a tightly regulated network involving multiple genes. The current understanding of the molecular mechanism behind cardiovascular development is insufficient and requires further research.

RESULTS

Transcriptome sequencing of three developmental stages in zebrafish embryos was performed and revealed three key cardiovascular developmental stages. Then, the differentially expressed genes (DEGs) involved in cardiovascular development were screened out. The three developmental stages were 18 (T1), 24 (T2), and 42 h post fertilization (hpf) (T3), and the three stages were confirmed by detecting differences in expression between cardiomyocyte and endothelial marker genes (cmlc2, fli1) using in situ hybridization, which represents the characteristics of cardiovascular development. Thousands of DEGs were identified using transcriptome analysis. Of them, 2605 DEGs were in T1-vs-T2, including 2003 up-regulated and 602 down-regulated genes, 6446 DEGs were in T1-vs-T3, consisting of 4608 up-regulated and 1838 down-regulated genes, and 3275 DEGs were in T2-vs-T3, including 2420 up-regulated and 855 down-regulated genes. There were 644 common DEGs and 167 common five-fold higher differentially expressed genes (HDEGs) identified, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID). Significant differences was observed in the levels of gene expression among different developmental stages in multiple GO terms and KEGG pathways, such as cell migration to the midline involved in heart development, cardiovascular system development, circulatory system process for biological processes of GO terms; and cardiac muscle contraction, adrenergic signaling in cardiomyocytes for KEGG pathways. These results demonstrated that these three stages were important period for the development of the cardiovascular system. Lastly, we used quantitative real-time PCR (qPCR) to validate the reliability of RNA-sequencing by selecting 21 DEGs.

CONCLUSIONS

These results demonstrated that these three stages represented the important periods for cardiovascular system development of zebrafish and some candidate genes was obtained and provided a solid foundation for additional functional studies of the DEGs.

Impacts of Cetylpyridinium Chloride on the Survival, Development, Behavior, and Oxidative Stress of Early-Life-Stage Zebrafish (Danio rerio)

Cetylpyridinium chloride (CPC) is a widely used surfactant that has been detected in various water ecosystems. However, knowledge on the toxicity of CPC to fish remains scarce. Here, we examined the survival, development, behavior, and oxidative stress in the early life stages of zebrafish exposed to CPC (0, 4, 40, 400, and 1200 μg/L) until 120 h post-fertilization (hpf). Results showed that CPC induced significant mortality at 400 and 1200 μg/L, with a 120 h-EC₅₀ value of 175.9 μg/L. CPC significantly decreased the heart rate of embryos (48 hpf; 4–400 μg/L) and larvae (72 hpf; 40 and 400 μg/L). At 120 hpf, CPC exhibited a dual effect on the locomotion activity (decreased at 400 μg/L and increased at 4 and 40 μg/L) and elevated the reactive oxygen species, superoxide dismutase, and glutathione levels in zebrafish larvae at 400 µg/L. In addition, a correlation analysis revealed that CPC-induced oxidative stress might play a critical role in mediating the cardiac and behavioral toxicity of CPC to zebrafish larvae. Our findings suggest that CPC may disturb the fish’s development, behavior, and oxidative status at environmentally relevant concentrations, which should not be ignored when assessing its potential risks to aquatic ecosystems.

HACE1 negatively regulates neuroinflammation through ubiquitylating and degrading Rac1 in Parkinson's disease models

Neuroinflammation plays an important role in neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease. HACE1 (HECT domain and Ankyrin repeat Containing E3 ubiquitin-protein ligase 1) is a tumor suppressor. Recent evidence suggests that HACE1 may be involved in oxidative stress responses. Due to the critical role of ROS in neuroinflammation, we speculated that HACE1 might participate in neuroinflammation and related neurodegenerative diseases, such as PD. In this study, we investigated the role of HACE1 in neuroinflammation of PD models. We showed that HACE1 knockdown exacerbated LPS-induced neuroinflammation in BV2 microglial cells in vitro through suppressing ubiquitination and degradation of activated Rac1, an NADPH oxidase subunit. Furthermore, we showed that HACE1 exerted vital neuronal protection through increasing Rac1 activity and stability in LPS-treated SH-SY5Y cells, as HACE1 knockdown leading to lower tolerance to LPS challenge. In MPTP-induced acute PD mouse model, HACE1 knockdown exacerbated motor deficits by activating Rac1. Finally, mutant α-synuclein (A53T)-overexpressing mice, a chronic PD mouse model, exhibited age-dependent reduction of HACE1 levels in the midbrain and striatum, implicating that HACE1 participated in PD pathological progression. This study for the first time demonstrates that HACE1 is a negative regulator of neuroinflammation and involved in the PD pathogenesis by regulating Rac1 activity. The data support HACE1 as a potential target for PD and other neurodegenerative diseases.

Intersection of Redox Chemistry and Ubiquitylation: Post-Translational Modifications Required for Maintaining Cellular Homeostasis and Neuroprotection

Neurodegeneration has been predominantly recognized as neuronal breakdown induced by the accumulation of aggregated and/or misfolded proteins and remains a preliminary factor in age-dependent disease. Recently, critical regulating molecular mechanisms and cellular pathways have been shown to induce neurodegeneration long before aggregate accumulation could occur. Although this opens the possibility of identifying biomarkers for early onset diagnosis, many of these pathways vary in their modes of dysfunction while presenting similar clinical phenotypes. With selectivity remaining difficult, it is promising that these neuroprotective pathways are regulated through the ubiquitin-proteasome system (UPS). This essential post-translational modification (PTM) involves the specific attachment of ubiquitin onto a substrate, specifically marking the ubiquitin-tagged protein for its intracellular fate based upon the site of attachment, the ubiquitin chain type built, and isopeptide linkages between different ubiquitin moieties. This review highlights both the direct and indirect impact ubiquitylation has in oxidative stress response and neuroprotection, and how irregularities in these intricate processes lead towards the onset of neurodegenerative disease (NDD).

Loss of vacuolar-type H+-ATPase induces caspase-independent necrosis-like death of hair cells in zebrafish neuromasts

The vacuolar-type H+-ATPase (V-ATPase) is a multi-subunit proton pump that regulates cellular pH. V-ATPase activity modulates several cellular processes, but cell-type-specific functions remain poorly understood. Patients with mutations in specific V-ATPase subunits can develop sensorineural deafness, but the underlying mechanisms are unclear. Here, we show that V-ATPase mutations disrupt the formation of zebrafish neuromasts, which serve as a model to investigate hearing loss. V-ATPase mutant neuromasts are small and contain pyknotic nuclei that denote dying cells. Molecular markers and live imaging show that loss of V-ATPase induces mechanosensory hair cells in neuromasts, but not neighboring support cells, to undergo caspase-independent necrosis-like cell death. This is the first demonstration that loss of V-ATPase can lead to necrosis-like cell death in a specific cell type in vivo. Mechanistically, loss of V-ATPase reduces mitochondrial membrane potential in hair cells. Modulating the mitochondrial permeability transition pore, which regulates mitochondrial membrane potential, improves hair cell survival. These results have implications for understanding the causes of sensorineural deafness, and more broadly, reveal functions for V-ATPase in promoting survival of a specific cell type in vivo.

Structure and Function of HECT E3 Ubiquitin Ligases and their Role in Oxidative Stress

Ubiquitination is a modification after protein transcription that plays a vital role in maintaining the homeostasis of the cellular environment. The Homologous to E6AP C-terminus (HECT) family E3 ubiquitin ligases are a kind of E3 ubiquitin ligases with a C-terminal HECT domain that mediates the binding of ubiquitin to substrate proteins and a variable-length N-terminal extension. HECT-ubiquitinated ligases can be divided into three categories: NEDD4 superfamily, HERC superfamily, and other HECT superfamilies. HECT ubiquitin ligase plays an essential role in the development of many human diseases. In this review, we focus on the physiological and pathological processes involved in oxidative stress and the role of E3 ubiquitin ligase of the HECT family.

Isoniazid causes heart looping disorder in zebrafish embryos by the induction of oxidative stress

BACKGROUND

The cardiotoxicity of isoniazid on zebrafish embryos and its underlying mechanism is unclear.

METHODS

Here, we exposed zebrafish embryos at 4 h post-fertilization to different levels of isoniazid and recorded the morphology and number of malformed and dead embryos under the microscope.

RESULTS

The high concentration of isoniazid group showed more malformed and dead embryos than the low concentration of isoniazid group and control group. The morphology of the heart and its alteration were visualized using transgenic zebrafish (cmlc2: GFP) and confirmed by in situ hybridization. The negative effects of isoniazid on the developing heart were characterized by lower heart rate and more heart looping disorders. Mechanistically, PCR showed decreased expression of heart-specific transcription factors when exposed to isoniazid. Oxidative stress was induced by isoniazid in cardiomyocytes, mediated by decreased activities of catalase and superoxide dismutase, which were rescued by scavengers of reactive oxygen species.

CONCLUSION

In conclusion, this study demonstrated that isoniazid led to heart looping disturbance by the downregulation of cardiac-specific transcription factors and induction of cardiomyocyte apoptosis.

Role of WW domain E3 ubiquitin protein ligase 2 in modulating ubiquitination and Degradation of Septin4 in oxidative stress endothelial injury

Oxidative stress-associated endothelial injury is the initial event and major cause of multiple cardiovascular diseases such as atherosclerosis and hypertensive angiopathy. A protein homeostasis imbalance is a critical cause of endothelial injury, and homologous to E6AP C-terminus (HECT)-type E3 ubiquitin ligases are the core factors controlling protein homeostasis. Although HECT-type E3 ubiquitin ligases are involved in the regulation of cardiac development and diseases, their roles in endothelial injury remain largely unknown. This study aimed to identify which HECT-type E3 ubiquitin ligase is involved in endothelial injury and clarify the mechanisms at molecular, cellular, and organism levels. We revealed a novel role of the HECT-type E3 ubiquitin ligase WWP2 in regulating endothelial injury and vascular remodeling after endothelial injury. Endothelial/myeloid-specific WWP2 knockout in mice significantly aggravated angiotensin II/oxidative stress-induced endothelial injury and vascular remodeling after endothelial injury. The same results were obtained from in vitro experiments. Mechanistically, the endothelial injury factor Septin4 was identified as a novel physiological substrate of WWP2. In addition, WWP2 interacted with the GTPase domain of Septin4, ubiquitinating Septin4-K174 to degrade Septin4 through the ubiquitin-proteasome system, which inhibited the Septin4-PARP1 endothelial damage complex. These results identified the first endothelial injury-associated physiological pathway regulated by HECT-type E3 ubiquitin ligases in vivo as well as a unique proteolytic mechanism through which WWP2 controls endothelial injury and vascular remodeling after endothelial injury. These findings might provide a novel treatment strategy for oxidative stress-associated atherosclerosis and hypertensive vascular diseases.

Domestication may affect the maternal mRNA profile in unfertilized eggs, potentially impacting the embryonic development of Eurasian perch (Perca fluviatilis)

Domestication is an evolutionary process during which we expect populations to progressively adapt to an environment controlled by humans. It is accompanied by genetic and presumably epigenetic changes potentially leading to modifications in the transcriptomic profile in various tissues. Reproduction is a key function often affected by this process in numerous species, regardless of the mechanism. The maternal mRNA in fish eggs is crucial for the proper embryogenesis. Our working hypothesis is that modifications of maternal mRNAs may reflect potential genetic and/or epigenetic modifications occurring during domestication and could have consequences during embryogenesis. Consequently, we investigated the trancriptomic profile of unfertilized eggs from two populations of Eurasian perch. These two populations differed by their domestication histories (F1 vs. F7+-at least seven generations of reproduction in captivity) and were genetically differentiated (FST = 0.1055, p<0.05). A broad follow up of the oogenesis progression failed to show significant differences during oogenesis between populations. However, the F1 population spawned earlier with embryos presenting an overall higher survivorship than those from the F7+ population. The transcriptomic profile of unfertilized eggs showed 358 differentially expressed genes between populations. In conclusion, our data suggests that the domestication process may influence the regulation of the maternal transcripts in fish eggs, which could in turn explain differences of developmental success.