Abstract
Flies have an open circulatory system and their Blood Brain Barrier (BBB) surrounds the brain like a tight cap. The fly BBB consists of two layers of glial cells. The outer layer is formed by the Perineurial Glia (PG). The inner BBB layer consists of the Subperineurial Glia (SPG) that form the tight barrier that, like its mammalian counterpart, acts both as a diffusion and a xenobiotic transport barrier. Underneath the SPG lie the neuronal cell bodies. The Drosophila BBB shows the same barrier properties as the mammalian barrier and profiling of Drosophila BBB cells has shown a high degree of molecular conservation.
We have previously shown that the Drosophila BBB plays a sex-specific role in regulating behavior. Conditional adult feminization of SPG cells in otherwise normal males leads to significantly reduced courtship. In agreement with this, in a microarray screen of isolated SPG cells, we identified a number of male-enriched transcripts. One of them encodes the dopamine-2 like receptor (D2R). We have found that conditional knockdown of D2R in adult male Drosophila SPG decreases courtship. Likewise, D2R mutant males have courtship defects. They can be rescued by expression of wildtype D2R in the SPG cells of mature adult males, demonstrating a physiological requirement for the receptor in these cells for courtship control4. The D2R receptor is highly conserved. It has been found that it can act via biased signaling (through G protein or b-arrestin) in mammals. We have previously found that signaling through Gao and arrestin in the BBB is required for proper male courtship. Although D2R is best known for signaling through cAMP, we have not found a requirement for cAMP/PKA signaling for courtship. To investigate the signaling pathways downstream of D2R that are responsible for courtship control we have mutagenized D2R proteins and examined their ability to rescue D2R mutants. Based on Peterson et al. we designed proteins capable of G-protein or arrestin biased signaling, respectively, and tested their ability to rescue the courtship defects of D2R mutants. Our data suggest that D2R signaling through b-arrestin is a major mediator of BBB courtship control.
more »
« less
Characterizing the Role of SMYD2 in Mammalian Embryogenesis—Future Directions
The SET and MYND domain-containing (SMYD) family of lysine methyltransferases are essential in several mammalian developmental pathways. Although predominantly expressed in the heart, the role of SMYD2 in heart development has yet to be fully elucidated and has even been shown to be dispensable in a murine Nkx2-5-associated conditional knockout. Additionally, SMYD2 was recently shown to be necessary not only for lymphocyte development but also for the viability of hematopoietic leukemias. Based on the broad expression pattern of SMYD2 in mammalian tissues, it is likely that it plays pivotal roles in a host of additional normal and pathological processes. In this brief review, we consider what is currently known about the normal and pathogenic functions of SMYD2 and propose specific future directions for characterizing its role in embryogenesis.
more »
« less
- Award ID(s):
- 1930417
- NSF-PAR ID:
- 10208634
- Date Published:
- Journal Name:
- Veterinary Sciences
- Volume:
- 7
- Issue:
- 2
- ISSN:
- 2306-7381
- Page Range / eLocation ID:
- 63
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
more » « less
Emerging evidence has highlighted that the gut microbiota plays a critical role in the regulation of various aspects of mammalian physiology and behavior, including circadian rhythms. Circadian rhythms are fundamental behavioral and physiological processes that are governed by circadian pacemakers in the brain. Since mice are nocturnal, voluntary wheel running activity mostly occurs at night. This nocturnal wheel-running activity is driven by the primary circadian pacemaker located in the suprachiasmatic nucleus (SCN). Food anticipatory activity (FAA) is the increased bout of locomotor activity that precedes the scheduled short duration of a daily meal. FAA is controlled by the food-entrainable oscillator (FEO) located outside of the SCN. Several studies have shown that germ-free mice and mice with gut microbiota depletion altered those circadian behavioral rhythms. Therefore, this study was designed to test if the gut microbiota is involved in voluntary wheel running activity and FAA expression. To deplete gut microbiota, C57BL/6J wildtype mice were administered an antibiotic cocktail via their drinking water throughout the experiment. The effect of antibiotic cocktail treatment on wheel running activity rhythm in both female and male mice was not detectable with the sample size in our current study. Then mice were exposed to timed restricted feeding during the day. Both female and male mice treated with antibiotics exhibited normal FAA which was comparable with the FAA observed in the control group. Those results suggest that gut microbiota depletion has minimum effect on both circadian behavioral rhythms controlled by the SCN and FEO respectively. Our result contradicts recently published studies that reported significantly higher FAA levels in germ-free mice compared to their control counterparts and gut microbiota depletion significantly reduced voluntary activity by 50%.
-
more » « less
Abstract Age‐associated mitochondrial dysfunction and oxidative damage are primary causes for multiple health problems including sarcopenia and cardiovascular disease (CVD). Though the role of Nrf2, a transcription factor that regulates cytoprotective gene expression, in myopathy remains poorly defined, it has shown beneficial properties in both sarcopenia and CVD. Sulforaphane (SFN), a natural compound Nrf2‐related activator of cytoprotective genes, provides protection in several disease states including CVD and is in various stages of clinical trials, from cancer prevention to reducing insulin resistance. This study aimed to determine whether SFN may prevent age‐related loss of function in the heart and skeletal muscle. Cohorts of 2‐month‐old and 21‐ to 22‐month‐old mice were administered regular rodent diet or diet supplemented with SFN for 12 weeks. At the completion of the study, skeletal muscle and heart function, mitochondrial function, and Nrf2 activity were measured. Our studies revealed a significant drop in Nrf2 activity and mitochondrial functions, together with a loss of skeletal muscle and cardiac function in the old control mice compared to the younger age group. In the old mice, SFN restored Nrf2 activity, mitochondrial function, cardiac function, exercise capacity, glucose tolerance, and activation/differentiation of skeletal muscle satellite cells. Our results suggest that the age‐associated decline in Nrf2 signaling activity and the associated mitochondrial dysfunction might be implicated in the development of age‐related disease processes. Therefore, the restoration of Nrf2 activity and endogenous cytoprotective mechanisms by SFN may be a safe and effective strategy to protect against muscle and heart dysfunction due to aging.
-
Rationale: NAA15 (N-alpha-acetyltransferase 15) is a component of the NatA (N-terminal acetyltransferase complex). The mechanism by which NAA15 haploinsufficiency causes congenital heart disease remains unknown. To better understand molecular processes by which NAA15 haploinsufficiency perturbs cardiac development, we introduced NAA15 variants into human induced pluripotent stem cells (iPSCs) and assessed the consequences of these mutations on RNA and protein expression. Objective: We aim to understand the role of NAA15 haploinsufficiency in cardiac development by investigating proteomic effects on NatA complex activity and identifying proteins dependent upon a full amount of NAA15. Methods and Results: We introduced heterozygous loss of function, compound heterozygous, and missense residues (R276W) in iPSCs using CRISPR/Cas9. Haploinsufficient NAA15 iPSCs differentiate into cardiomyocytes, unlike NAA15 -null iPSCs, presumably due to altered composition of NatA. Mass spectrometry analyses reveal ≈80% of identified iPSC NatA targeted proteins displayed partial or complete N-terminal acetylation. Between null and haploinsufficient NAA15 cells, N-terminal acetylation levels of 32 and 9 NatA-specific targeted proteins were reduced, respectively. Similar acetylation loss in few proteins occurred in NAA15 R276W induced pluripotent stem cells. In addition, steady-state protein levels of 562 proteins were altered in both null and haploinsufficient NAA15 cells; 18 were ribosomal-associated proteins. At least 4 proteins were encoded by genes known to cause autosomal dominant congenital heart disease. Conclusions: These studies define a set of human proteins that requires a full NAA15 complement for normal synthesis and development. A 50% reduction in the amount of NAA15 alters levels of at least 562 proteins and N-terminal acetylation of only 9 proteins. One or more modulated proteins are likely responsible for NAA15-haploinsufficiency mediated congenital heart disease. Additionally, genetically engineered induced pluripotent stem cells provide a platform for evaluating the consequences of amino acid sequence variants of unknown significance on NAA15 function.more » « less
-
Physio-logging has the potential to explore the processes that underlie the dive behavior and ecology of marine mammals and seabirds, as well as evaluate their adaptability to environmental change and other stressors. Regulation of heart rate lies at the core of the physiological processes that determine dive capacity and performance. The bio-logging of heart rate in unrestrained animals diving at sea was infeasible, even unimaginable in the mid-1970s. To provide a historical perspective, I review my 40-year experience in the development of heart rate physio-loggers and the evolution of a digital electrocardiogram (ECG) recorder that is still in use today. I highlight documentation of the ECG and the interpretation of heart rate profiles in the largest of avian and mammalian divers, the emperor penguin and blue whale.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/vetsci7020063
