IU Indianapolis ScholarWorks :: Browsing by Subject "Zebrafish"

Browsing by Subject "Zebrafish"

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12-lipoxygenase Promotes Macrophage Infiltration and Pancreatic Islet Dysfunction in the Vertebrate Models of Diabetes Pathogenesis
(2020-05) Kulkarni, Abhishek Anant; Harrington, Maureen; Mirmira, Raghavendra; Anderson, Ryan; Goebl, Mark; Mosley, Amber; Marrs, James
Diabetes is a morbid metabolic disorder that affects almost 500 million people worldwide. Although multiple factors contribute to diabetes pathogenesis, pancreatic islet inflammation and dysfunction are shared characteristics of its major forms. 12- lipoxygenase (12-LOX), an enzyme involved in lipid metabolism, has been implicated in islet inflammation. 12-LOX generates reactive oxygen species (ROS) that activate inflammation and serve as major contributors to islet dysfunction. Importantly, since ROS are transient moieties, they are challenging to study in vivo. Hence, establishing better animal models of ROS-mediated stress is critical to facilitate the discovery and preclinical testing of novel diabetes therapeutics. Here, I have adapted a zebrafish model of conditional β-cell injury, which is regulated by the administration of the prodrug metronidazole (MTZ), to study responses to ROS in vivo. I demonstrate that with MTZ treatment, ROS are generated within β-cells and subsequently exhibit recruitment of macrophages into the islet and induction of β-cell death. I utilized this model to uncover roles for macrophages and 12-LOX during islet injury. Excessive macrophage infiltration exacerbates islet inflammation and dysfunction. Interestingly, on the depletion of macrophages in zebrafish, I observed that β-cells recovered normal function upon cessation of prodrug treatment. This suggests that infiltrating macrophages promote maladaptive inflammation and premature removal of damaged β-cells. Thus, limiting the macrophage infiltration may be a therapeutic approach to restoring β-cell function. Based on the established roles of 12-LOX in other contexts, I hypothesized that its inhibition would prevent the localized infiltration of proinflammatory macrophages. To test this, I used both zebrafish and mouse models and observed a significant reduction in macrophage migration upon loss of 12- LOX activity. Furthermore, I found that expression of CXCR3, a crucial receptor regulating migration, was significantly reduced in 12-LOX loss-of-function macrophages. These data suggest a role for 12-LOX in macrophages, which is conserved across species. Collectively, my study reveals novel roles for 12-LOX in macrophage function and provides testable therapeutic targets for the resolution of inflammation-induced damage in the pancreatic islets.
A 12-lipoxygenase-Gpr31 signaling axis is required for pancreatic organogenesis in the zebrafish
(Wiley, 2020-11) Hernandez-Perez, Marimar; Kulkarni, Abhishek; Samala, Niharika; Sorrell, Cody; El, Kimberly; Haider, Isra; Aleem, Ansari Mukhtar; Holman, Theodore R.; Rai, Ganesha; Tersey, Sarah A.; Mirmira, Raghavendra G.; Anderson, Ryan M.; Pediatrics, School of Medicine
12-Lipoxygenase (12-LOX) is a key enzyme in arachidonic acid metabolism, and alongside its major product, 12-HETE, plays a key role in promoting inflammatory signaling during diabetes pathogenesis. Although 12-LOX is a proposed therapeutic target to protect pancreatic islets in the setting of diabetes, little is known about the consequences of blocking its enzymatic activity during embryonic development. Here, we have leveraged the strengths of the zebrafish-genetic manipulation and pharmacologic inhibition-to interrogate the role of 12-LOX in pancreatic development. Lipidomics analysis during zebrafish development demonstrated that 12-LOX-generated metabolites of arachidonic acid increase sharply during organogenesis stages, and that this increase is blocked by morpholino-directed depletion of 12-LOX. Furthermore, we found that either depletion or inhibition of 12-LOX impairs both exocrine pancreas growth and unexpectedly, the generation of insulin-producing β cells. We demonstrate that morpholino-mediated knockdown of GPR31, a purported G-protein-coupled receptor for 12-HETE, largely phenocopies both the depletion and the inhibition of 12-LOX. Moreover, we show that loss of GPR31 impairs pancreatic bud fusion and pancreatic duct morphogenesis. Together, these data provide new insight into the requirement of 12-LOX in pancreatic organogenesis and islet formation, and additionally provide evidence that its effects are mediated via a signaling axis that includes the 12-HETE receptor GPR31.
The analysis of heterotaxy patients reveals new loss-of-function variants of GRK5
(SpringerNature, 2016-09-13) Lessel, Davor; Muhammad, Tariq; Tena, Teresa Casar; Moepps, Barbara; Burkhalter, Martin D.; Hitz, Marc-Phillip; Toka, Okan; Rentzsch, Axel; Schubert, Stephan; Schalinski, Adelheid; Bauer, Ulrike M. M.; Kubisch, Christian; Ware, Stephanie M.; Philipp, Melanie; Department of Pediatrics, IU School of Medicine
G protein-coupled receptor kinase 5 (GRK5) is a regulator of cardiac performance and a potential therapeutic target in heart failure in the adult. Additionally, we have previously classified GRK5 as a determinant of left-right asymmetry and proper heart development using zebrafish. We thus aimed to identify GRK5 variants of functional significance by analysing 187 individuals with laterality defects (heterotaxy) that were associated with a congenital heart defect (CHD). Using Sanger sequencing we identified two moderately frequent variants in GRK5 with minor allele frequencies <10%, and seven very rare polymorphisms with minor allele frequencies <1%, two of which are novel variants. Given their evolutionarily conserved position in zebrafish, in-depth functional characterisation of four variants (p.Q41L, p.G298S, p.R304C and p.T425M) was performed. We tested the effects of these variants on normal subcellular localisation and the ability to desensitise receptor signalling as well as their ability to correct the left-right asymmetry defect upon Grk5l knockdown in zebrafish. While p.Q41L, p.R304C and p.T425M responded normally in the first two aspects, neither p.Q41L nor p.R304C were capable of rescuing the lateralisation phenotype. The fourth variant, p.G298S was identified as a complete loss-of-function variant in all assays and provides insight into the functions of GRK5.
Another Swim in the Extensive Pool of Zebrafish Research
(MDPI, 2024-02-29) Marrs, James A.; Sarmah, Swapnalee; Biology, School of Science
BICRA, a SWI/SNF Complex Member, Is Associated with BAF-Disorder Related Phenotypes in Humans and Model Organisms
(Elsevier, 2020-12-03) Barish, Scott; Barakat, Tahsin Stefan; Michel, Brittany C.; Mashtalir, Nazar; Phillips, Jennifer B.; Valencia, Alfredo M.; Ugur, Berrak; Wegner, Jeremy; Scott, Tiana M.; Bostwick, Brett; Murdock, David R.; Dai, Hongzheng; Perenthaler, Elena; Nikoncuk, Anita; van Slegtenhorst, Marjon; Brooks, Alice S.; Keren, Boris; Nava, Caroline; Mignot, Cyril; Douglas, Jessica; Rodan, Lance; Nowak, Catherine; Ellard, Sian; Stals, Karen; Lynch, Sally Ann; Faoucher, Marie; Lesca, Gaetan; Edery, Patrick; Engleman, Kendra L.; Zhou, Dihong; Thiffault, Isabelle; Herriges, John; Gass, Jennifer; Louie, Raymond J.; Stolerman, Elliot; Washington, Camerun; Vetrini, Francesco; Otsubo, Aiko; Pratt, Victoria M.; Conboy, Erin; Treat, Kayla; Shannon, Nora; Camacho, Jose; Wakeling, Emma; Yuan, Bo; Chen, Chun-An; Rosenfeld, Jill A.; Westerfield, Monte; Wangler, Michael; Yamamoto, Shinya; Kadoch, Cigall; Scott, Daryl A.; Bellen, Hugo J.; Medical and Molecular Genetics, School of Medicine
SWI/SNF-related intellectual disability disorders (SSRIDDs) are rare neurodevelopmental disorders characterized by developmental disability, coarse facial features, and fifth digit/nail hypoplasia that are caused by pathogenic variants in genes that encode for members of the SWI/SNF (or BAF) family of chromatin remodeling complexes. We have identified 12 individuals with rare variants (10 loss-of-function, 2 missense) in the BICRA (BRD4 interacting chromatin remodeling complex-associated protein) gene, also known as GLTSCR1, which encodes a subunit of the non-canonical BAF (ncBAF) complex. These individuals exhibited neurodevelopmental phenotypes that include developmental delay, intellectual disability, autism spectrum disorder, and behavioral abnormalities as well as dysmorphic features. Notably, the majority of individuals lack the fifth digit/nail hypoplasia phenotype, a hallmark of most SSRIDDs. To confirm the role of BICRA in the development of these phenotypes, we performed functional characterization of the zebrafish and Drosophila orthologs of BICRA. In zebrafish, a mutation of bicra that mimics one of the loss-of-function variants leads to craniofacial defects possibly akin to the dysmorphic facial features seen in individuals harboring putatively pathogenic BICRA variants. We further show that Bicra physically binds to other non-canonical ncBAF complex members, including the BRD9/7 ortholog, CG7154, and is the defining member of the ncBAF complex in flies. Like other SWI/SNF complex members, loss of Bicra function in flies acts as a dominant enhancer of position effect variegation but in a more context-specific manner. We conclude that haploinsufficiency of BICRA leads to a unique SSRIDD in humans whose phenotypes overlap with those previously reported.
Collagen COL22A1 maintains vascular stability and mutations in COL22A1 are potentially associated with intracranial aneurysms
(The Company of Biologists, 2018-12-12) Ton, Quynh V.; Leino, Daniel; Mowery, Sarah A.; Bredemeier, Nina O.; Lafontant, Pascal J.; Lubert, Allison; Gurung, Suman; Farlow, Janice L.; Foroud, Tatiana M.; Broderick, Joseph; Sumanas, Saulius; Medical and Molecular Genetics, School of Medicine
Collagen XXII (COL22A1) is a quantitatively minor collagen, which belongs to the family of fibril-associated collagens with interrupted triple helices. Its biological function has been poorly understood. Here, we used a genome-editing approach to generate a loss-of-function mutant in zebrafish col22a1 Homozygous mutant adults exhibit increased incidence of intracranial hemorrhages, which become more prominent with age and after cardiovascular stress. Homozygous col22a1 mutant embryos show higher sensitivity to cardiovascular stress and increased vascular permeability, resulting in a greater percentage of embryos with intracranial hemorrhages. Mutant embryos also exhibit dilations and irregular structure of cranial vessels. To test whether COL22A1 is associated with vascular disease in humans, we analyzed data from a previous study that performed whole-exome sequencing of 45 individuals from seven families with intracranial aneurysms. The rs142175725 single-nucleotide polymorphism was identified, which segregated with the phenotype in all four affected individuals in one of the families, and affects a highly conserved E736 residue in COL22A1 protein, resulting in E736D substitution. Overexpression of human wild-type COL22A1, but not the E736D variant, partially rescued the col22a1 loss-of-function mutant phenotype in zebrafish embryos. Our data further suggest that the E736D mutation interferes with COL22A1 protein secretion, potentially leading to endoplasmic reticulum stress. Altogether, these results argue that COL22A1 is required to maintain vascular integrity. These data further suggest that mutations in COL22A1 could be one of the risk factors for intracranial aneurysms in humans.
Complex cardiac defects after ethanol exposure during discrete cardiogenic events in zebrafish: prevention with folic acid
(Wiley, 2013-10) Swapnalee, Sarmah; Marrs, James A.; Biology, School of Science
Fetal alcohol spectrum disorder (FASD) describes a range of birth defects including various congenital heart defects (CHDs). Mechanisms of FASD-associated CHDs are not understood. Whether alcohol interferes with a single critical event or with multiple events in heart formation is not known. RESULTS: Our zebrafish embryo experiments showed that ethanol interrupts different cardiac regulatory networks and perturbs multiple steps of cardiogenesis (specification, myocardial migration, looping, chamber morphogenesis, and endocardial cushion formation). Ethanol exposure during gastrulation until cardiac specification or during myocardial midline migration did not produce severe or persistent heart development defects. However, exposure comprising gastrulation until myocardial precursor midline fusion or during heart patterning stages produced aberrant heart looping and defective endocardial cushions. Continuous exposure during entire cardiogenesis produced complex cardiac defects leading to severely defective myocardium, endocardium, and endocardial cushions. Supplementation of retinoic acid with ethanol partially rescued early heart developmental defects, but the endocardial cushions did not form correctly. In contrast, supplementation of folic acid rescued normal heart development, including the endocardial cushions. CONCLUSIONS: Our results indicate that ethanol exposure interrupted divergent cardiac morphogenetic events causing heart defects. Folic acid supplementation was effective in preventing a wide spectrum of ethanol-induced heart developmental defects.
Coordinating cardiomyocyte interactions to direct ventricular chamber morphogenesis
(SpringerNature, 2016-06-30) Han, Peidong; Bloomekatz, Joshua; Ren, Jie; Zhang, Ruilin; Grinstein, Jonathan D.; Zhao, Long; Burns, C. Geoffrey; Burns, Caroline E.; Anderson, Ryan M.; Chi, Neil C.; Department of Pediatrics, IU School of Medicine
Many organs are composed of complex tissue walls that are structurally organized to optimize organ function. In particular, the ventricular myocardial wall of the heart comprises an outer compact layer that concentrically encircles the ridge-like inner trabecular layer. Although disruption in the morphogenesis of this myocardial wall can lead to various forms of congenital heart disease and non-compaction cardiomyopathies, it remains unclear how embryonic cardiomyocytes assemble to form ventricular wall layers of appropriate spatial dimensions and myocardial mass. Here we use advanced genetic and imaging tools in zebrafish to reveal an interplay between myocardial Notch and Erbb2 signalling that directs the spatial allocation of myocardial cells to their proper morphological positions in the ventricular wall. Although previous studies have shown that endocardial Notch signalling non-cell-autonomously promotes myocardial trabeculation through Erbb2 and bone morphogenetic protein (BMP) signalling, we discover that distinct ventricular cardiomyocyte clusters exhibit myocardial Notch activity that cell-autonomously inhibits Erbb2 signalling and prevents cardiomyocyte sprouting and trabeculation. Myocardial-specific Notch inactivation leads to ventricles of reduced size and increased wall thickness because of excessive trabeculae, whereas widespread myocardial Notch activity results in ventricles of increased size with a single-cell-thick wall but no trabeculae. Notably, this myocardial Notch signalling is activated non-cell-autonomously by neighbouring Erbb2-activated cardiomyocytes that sprout and form nascent trabeculae. Thus, these findings support an interactive cellular feedback process that guides the assembly of cardiomyocytes to morphologically create the ventricular myocardial wall and more broadly provide insight into the cellular dynamics of how diverse cell lineages organize to create form.
Effects of GSK3-β Inhibitors on Wnt Signaling in Zebrafish Fin Regeneration: Chemical Biology
(2014-04-11) Brannick, Angelica; Mahin, Jennifer L.; Farrel, Mark; Curtis, Courtney; Sarmah, Swapnalee; Collins, Kayla; Chu, Shaoyou; Sato, Mas; Sanchez-Felix, Manuel
In order to develop beneficial drugs for osteoporosis it is important to understand the molecular mechanisms of bone regeneration and define specific regulatory factors. Zebrafish can regenerate damaged tissues, and they prove to be a good model to study bone growth and repair. Previous research showed that GSK3β inhibitor compound at various concentrations and for different treatment periods effectively stimulated fin regeneration. Conducted experiments identified temporal and spatial fluctuations on individual gene markers after GSK3β inhibitor treatment at various concentrations. Recent analyzed data uses the Lilly Research Labs experimental compound LSN 2105786 at 3 nM and 5 nM to stimulate tissue regeneration to determine whether activating Wnt signaling produces cell proliferation and β-catenin translocation to the nucleus for zebrafish bone regeneration. This research has potential to identify mechanism of bone growth and repair, leading to more suitable drugs for patients suffering with osteoporosis.
Elf3 deficiency during zebrafish development alters extracellular matrix organization and disrupts tissue morphogenesis
(PLOS, 2022-11-16) Sarmah, Swapnalee; Hawkins, Matthew R.; Manikandan, Priyadharshini; Farrell, Mark; Marrs , James A.; Biology, School of Science
E26 transformation specific (ETS) family transcription factors are expressed during embryogenesis and are involved in various cellular processes such as proliferation, migration, differentiation, angiogenesis, apoptosis, and survival of cellular lineages to ensure appropriate development. Dysregulated expression of many of the ETS family members is detected in different cancers. The human ELF3, a member of the ETS family of transcription factors, plays a role in the induction and progression of human cancers is well studied. However, little is known about the role of ELF3 in early development. Here, the zebrafish elf3 was cloned, and its expression was analyzed during zebrafish development. Zebrafish elf3 is maternally deposited. At different developmental stages, elf3 expression was detected in different tissue, mainly neural tissues, endoderm-derived tissues, cartilage, heart, pronephric duct, blood vessels, and notochord. The expression levels were high at the tissue boundaries. Elf3 loss-of-function consequences were examined by using translation blocking antisense morpholino oligonucleotides, and effects were validated using CRISPR/Cas9 knockdown. Elf3-knockdown produced short and bent larvae with notochord, craniofacial cartilage, and fin defects. The extracellular matrix (ECM) in the fin and notochord was disorganized. Neural defects were also observed. Optic nerve fasciculation (bundling) and arborization in the optic tectum were defective in Elf3-morphants, and fragmentation of spinal motor neurons were evident. Dysregulation of genes encoding ECM proteins and matrix metalloprotease (MMP) and disorganization of ECM may play a role in the observed defects in Elf3 morphants. We conclude that zebrafish Elf3 is required for epidermal, mesenchymal, and neural tissue development.

Browsing by Subject "Zebrafish"

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