1
|
Axelrod S, Li X, Sun Y, Lincoln S, Terceros A, O’Neil J, Wang Z, Nguyen A, Vora A, Spicer C, Shapiro B, Young MW. The Drosophila blood-brain barrier regulates sleep via Moody G protein-coupled receptor signaling. Proc Natl Acad Sci U S A 2023; 120:e2309331120. [PMID: 37831742 PMCID: PMC10589661 DOI: 10.1073/pnas.2309331120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/28/2023] [Indexed: 10/15/2023] Open
Abstract
Sleep is vital for most animals, yet its mechanism and function remain unclear. We found that permeability of the BBB (blood-brain barrier)-the organ required for the maintenance of homeostatic levels of nutrients, ions, and other molecules in the brain-is modulated by sleep deprivation (SD) and can cell-autonomously effect sleep changes. We observed increased BBB permeability in known sleep mutants as well as in acutely sleep-deprived animals. In addition to molecular tracers, SD-induced BBB changes also increased the penetration of drugs used in the treatment of brain pathologies. After chronic/genetic or acute SD, rebound sleep or administration of the sleeping aid gaboxadol normalized BBB permeability, showing that SD effects on the BBB are reversible. Along with BBB permeability, RNA levels of the BBB master regulator moody are modulated by sleep. Conversely, altering BBB permeability alone through glia-specific modulation of moody, gαo, loco, lachesin, or neuroglian-each a well-studied regulator of BBB function-was sufficient to induce robust sleep phenotypes. These studies demonstrate a tight link between BBB permeability and sleep and indicate a unique role for the BBB in the regulation of sleep.
Collapse
Affiliation(s)
- Sofia Axelrod
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Xiaoling Li
- International Personalized Cancer Center, Tianjin Cancer Hospital Airport Hospital, Tianjin300308, China
| | - Yingwo Sun
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Samantha Lincoln
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Andrea Terceros
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Jenna O’Neil
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Zikun Wang
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Andrew Nguyen
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Aabha Vora
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Carmen Spicer
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Benjamin Shapiro
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| | - Michael W. Young
- Laboratory of Genetics, The Rockefeller University, New York, NY10065
| |
Collapse
|
2
|
Love CR, Gautam S, Lama C, Le NH, Dauwalder B. The Drosophila dopamine 2-like receptor D2R (Dop2R) is required in the blood brain barrier for male courtship. GENES, BRAIN, AND BEHAVIOR 2023; 22:e12836. [PMID: 36636829 PMCID: PMC9994173 DOI: 10.1111/gbb.12836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/11/2022] [Accepted: 12/22/2022] [Indexed: 01/14/2023]
Abstract
The blood brain barrier (BBB) has the essential function to protect the brain from potentially hazardous molecules while also enabling controlled selective uptake. How these processes and signaling inside BBB cells control neuronal function is an intense area of interest. Signaling in the adult Drosophila BBB is required for normal male courtship behavior and relies on male-specific molecules in the BBB. Here we show that the dopamine receptor D2R is expressed in the BBB and is required in mature males for normal mating behavior. Conditional adult male knockdown of D2R in BBB cells causes courtship defects. The courtship defects observed in genetic D2R mutants can be rescued by expression of normal D2R specifically in the BBB of adult males. Drosophila BBB cells are glial cells. Our findings thus identify a specific glial function for the DR2 receptor and dopamine signaling in the regulation of a complex behavior.
Collapse
Affiliation(s)
- Cameron R Love
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA.,Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey, USA
| | - Sumit Gautam
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Chamala Lama
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Nhu Hoa Le
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Brigitte Dauwalder
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| |
Collapse
|
3
|
Arkov AL. Looking at the Pretty "Phase" of Membraneless Organelles: A View From Drosophila Glia. Front Cell Dev Biol 2022; 10:801953. [PMID: 35198559 PMCID: PMC8859445 DOI: 10.3389/fcell.2022.801953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Membraneless granules assemble in different cell types and cellular loci and are the focus of intense research due to their fundamental importance for cellular organization. These dynamic organelles are commonly assembled from RNA and protein components and exhibit soft matter characteristics of molecular condensates currently characterized with biophysical approaches and super-resolution microscopy imaging. In addition, research on the molecular mechanisms of the RNA-protein granules assembly provided insights into the formation of abnormal granules and molecular aggregates, which takes place during many neurodegenerative disorders including Parkinson's diseases (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD). While these disorders are associated with formation of abnormal granules, membraneless organelles are normally assembled in neurons and contribute to translational control and affect stability of neuronal RNAs. More recently, a new subtype of membraneless granules was identified in Drosophila glia (glial granules). Interestingly, glial granules were found to contain proteins which are the principal components of the membraneless granules in germ cells (germ granules), indicating some similarity in the functional assembly of these structures in glia and germline. This mini review highlights recent research on glial granules in the context of other membraneless organelles, including their assembly mechanisms and potential functions in the nervous system.
Collapse
Affiliation(s)
- Alexey L Arkov
- Department of Biological Sciences, Murray State University, Murray, KY, United States
| |
Collapse
|
4
|
The nuclear receptor Hr46/Hr3 is required in the blood brain barrier of mature males for courtship. PLoS Genet 2022; 18:e1009519. [PMID: 35077443 PMCID: PMC8815886 DOI: 10.1371/journal.pgen.1009519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 02/04/2022] [Accepted: 12/24/2021] [Indexed: 11/19/2022] Open
Abstract
The blood brain barrier (BBB) forms a stringent barrier that protects the brain from components in the circulation that could interfere with neuronal function. At the same time, the BBB enables selective transport of critical nutrients and other chemicals to the brain. Beyond these functions, another recently recognized function is even less characterized, specifically the role of the BBB in modulating behavior by affecting neuronal function in a sex-dependent manner. Notably, signaling in the adult Drosophila BBB is required for normal male courtship behavior. Courtship regulation also relies on male-specific molecules in the BBB. Our previous studies have demonstrated that adult feminization of these cells in males significantly lowered courtship. Here, we conducted microarray analysis of BBB cells isolated from males and females. Findings revealed that these cells contain male- and female-enriched transcripts, respectively. Among these transcripts, nuclear receptor Hr46/Hr3 was identified as a male-enriched BBB transcript. Hr46/Hr3 is best known for its essential roles in the ecdysone response during development and metamorphosis. In this study, we demonstrate that Hr46/Hr3 is specifically required in the BBB cells for courtship behavior in mature males. The protein is localized in the nuclei of sub-perineurial glial cells (SPG), indicating that it might act as a transcriptional regulator. These data provide a catalogue of sexually dimorphic BBB transcripts and demonstrate a physiological adult role for the nuclear receptor Hr46/Hr3 in the regulation of male courtship, a novel function that is independent of its developmental role.
Collapse
|
5
|
RNAi-based screens uncover a potential new role for the orphan neuropeptide receptor Moody in Drosophila female germline stem cell maintenance. PLoS One 2020; 15:e0243756. [PMID: 33307547 PMCID: PMC7732368 DOI: 10.1371/journal.pone.0243756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 11/25/2020] [Indexed: 01/18/2023] Open
Abstract
Reproduction is highly sensitive to changes in physiology and the external environment. Neuropeptides are evolutionarily conserved signaling molecules that regulate multiple physiological processes. However, the potential reproductive roles of many neuropeptide signaling pathways remain underexplored. Here, we describe the results of RNAi-based screens in Drosophila melanogaster to identify neuropeptides/neuropeptide receptors with potential roles in oogenesis. The screen read-outs were either the number of eggs laid per female per day over time or fluorescence microscopy analysis of dissected ovaries. We found that the orphan neuropeptide receptor encoded by moody (homologous to mammalian melatonin receptors) is likely required in somatic cells for normal egg production and proper germline stem cell maintenance. However, the egg laying screens had low signal-to-noise ratio and did not lead to the identification of additional candidates. Thus, although egg count assays might be useful for large-scale screens to identify oogenesis regulators that result in dramatic changes in oogenesis, more labor-intensive microscopy-based screen are better applicable for identifying new physiological regulators of oogenesis with more subtle phenotypes.
Collapse
|
6
|
Wat LW, Chao C, Bartlett R, Buchanan JL, Millington JW, Chih HJ, Chowdhury ZS, Biswas P, Huang V, Shin LJ, Wang LC, Gauthier MPL, Barone MC, Montooth KL, Welte MA, Rideout EJ. A role for triglyceride lipase brummer in the regulation of sex differences in Drosophila fat storage and breakdown. PLoS Biol 2020; 18:e3000595. [PMID: 31961851 PMCID: PMC6994176 DOI: 10.1371/journal.pbio.3000595] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 01/31/2020] [Accepted: 01/03/2020] [Indexed: 01/26/2023] Open
Abstract
Triglycerides are the major form of stored fat in all animals. One important determinant of whole-body fat storage is whether an animal is male or female. Here, we use Drosophila, an established model for studies on triglyceride metabolism, to gain insight into the genes and physiological mechanisms that contribute to sex differences in fat storage. Our analysis of triglyceride storage and breakdown in both sexes identified a role for triglyceride lipase brummer (bmm) in the regulation of sex differences in triglyceride homeostasis. Normally, male flies have higher levels of bmm mRNA both under normal culture conditions and in response to starvation, a lipolytic stimulus. We find that loss of bmm largely eliminates the sex difference in triglyceride storage and abolishes the sex difference in triglyceride breakdown via strongly male-biased effects. Although we show that bmm function in the fat body affects whole-body triglyceride levels in both sexes, in males, we identify an additional role for bmm function in the somatic cells of the gonad and in neurons in the regulation of whole-body triglyceride homeostasis. Furthermore, we demonstrate that lipid droplets are normally present in both the somatic cells of the male gonad and in neurons, revealing a previously unrecognized role for bmm function, and possibly lipid droplets, in these cell types in the regulation of whole-body triglyceride homeostasis. Taken together, our data reveal a role for bmm function in the somatic cells of the gonad and in neurons in the regulation of male–female differences in fat storage and breakdown and identify bmm as a link between the regulation of triglyceride homeostasis and biological sex. An investigation of the genetic and physiological mechanisms underlying sex differences in fat storage and breakdown in the fruit fly Drosophila identifies previously unrecognized sex- and cell type-specific roles for the conserved triglyceride lipase brummer.
Collapse
Affiliation(s)
- Lianna W. Wat
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Charlotte Chao
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Rachael Bartlett
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Justin L. Buchanan
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Jason W. Millington
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Hui Ju Chih
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Zahid S. Chowdhury
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Puja Biswas
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Vivian Huang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Leah J. Shin
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Lin Chuan Wang
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Marie-Pierre L. Gauthier
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Maria C. Barone
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Kristi L. Montooth
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Michael A. Welte
- Department of Biology, University of Rochester, Rochester, New York, United States of America
| | - Elizabeth J. Rideout
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
| |
Collapse
|
7
|
Wu VM, Huynh E, Tang S, Uskoković V. Brain and bone cancer targeting by a ferrofluid composed of superparamagnetic iron-oxide/silica/carbon nanoparticles (earthicles). Acta Biomater 2019; 88:422-447. [PMID: 30711662 DOI: 10.1016/j.actbio.2019.01.064] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 01/11/2019] [Accepted: 01/30/2019] [Indexed: 01/02/2023]
Abstract
Despite the advances in molecularly targeted therapies, delivery across the blood-brain barrier (BBB) and the targeting of brain tumors remains a challenge. Like brain, bone is a common site of metastasis and requires therapies capable of discerning the tumor from its healthy cellular milieu. To tackle these challenges, we made a variation on the previously proposed concept of the earthicle and fabricated an aqueous, surfactant-free ferrofluid containing superparamagnetic iron oxide nanoparticles (SPIONs) coated with silicate mesolayers and carbon shells, having 13 nm in size on average. Nanoparticles were synthesized hydrothermally and characterized using a range of spectroscopic, diffractometric, hydrodynamic and electron microscopy techniques. The double coating on SPIONs affected a number of physicochemical and biological properties, including colloidal stability and cancer targeting efficacy. Nanoparticles decreased the viability of glioblastoma and osteosarcoma cells and tumors more than that of their primary and non-transformed analogues. They showed a greater preference for cancer cells because of a higher rate of uptake by these cells and a pronounced adherence to cancer cell membrane. Even in an ultralow alternate magnetic field, nanoparticles generated sufficient heat to cause tumor death. Nanoparticles in MDCK-MDR1 BBB model caused mislocalization of claudin-1 at the tight junctions, underexpression of ZO-1 and no effect on occludin-1 and transepithelial resistance. Nanoparticles were detected in the basolateral compartments and examination of LAMP1 demonstrated that nanoparticles escaped the lysosome, traversed the BBB transcellularly and localized to the optic lobes of the third instar larval brains of Drosophila melanogaster. The passage was noninvasive and caused no adverse systemic effects to the animals. In conclusion, these nanoparticulate ferrofluids preferentially bind to cancer cells and, hence, exhibit a greater toxicity in these cells compared to the primary cells. They are also effective against solid tumors in vitro, can cross the BBB in Drosophila, and are nontoxic based on the developmental studies of flies raised in ferrofluid-infused media. STATEMENT OF SIGNIFICANCE: We demonstrate that a novel, hydrothermally synthesized composite nanoparticle-based ferrofluid is effective in reducing the viability of osteosarcoma and glioblastoma cells in vitro, while having minimal effects on primary cell lines. In 3D tumor spheroids, nanoparticles greatly reduced the metastatic migration of cancer cells, while the tumor viability was reduced compared to the control group by applying magnetic hyperthermia to nanoparticle-treated spheroids. Both in vitro and in vivo models of the blood-brain barrier evidence the ability of nanoparticles to cross the barrier and localize to the brain tissue. These composite nanoparticles show great promise as an anticancer biomaterial for the treatment of different types of cancer and may serve as an alternative or addendum to traditional chemotherapies.
Collapse
Affiliation(s)
- Victoria M Wu
- Advanced Materials and Nanobiotechnology Laboratory, Center for Targeted Drug Delivery, Department of Biomedical and Pharmaceutical Sciences, Chapman University, Irvine, CA 92618-1908, USA
| | - Eric Huynh
- Advanced Materials and Nanobiotechnology Laboratory, Center for Targeted Drug Delivery, Department of Biomedical and Pharmaceutical Sciences, Chapman University, Irvine, CA 92618-1908, USA
| | - Sean Tang
- Advanced Materials and Nanobiotechnology Laboratory, Center for Targeted Drug Delivery, Department of Biomedical and Pharmaceutical Sciences, Chapman University, Irvine, CA 92618-1908, USA
| | - Vuk Uskoković
- Advanced Materials and Nanobiotechnology Laboratory, Center for Targeted Drug Delivery, Department of Biomedical and Pharmaceutical Sciences, Chapman University, Irvine, CA 92618-1908, USA; Advanced Materials and Nanobiotechnology Laboratory, Department of Bioengineering, University of Illinois, Chicago, IL 60607-7052, USA.
| |
Collapse
|
8
|
Artiushin G, Zhang SL, Tricoire H, Sehgal A. Endocytosis at the Drosophila blood-brain barrier as a function for sleep. eLife 2018; 7:e43326. [PMID: 30475209 PMCID: PMC6255390 DOI: 10.7554/elife.43326] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/09/2018] [Indexed: 12/18/2022] Open
Abstract
Glia are important modulators of neural activity, yet few studies link glia to sleep regulation. We find that blocking activity of the endocytosis protein, dynamin, in adult Drosophila glia increases sleep and enhances sleep need, manifest as resistance to sleep deprivation. Surface glia comprising the fly equivalent of the blood-brain barrier (BBB) mediate the effect of dynamin on sleep. Blocking dynamin in the surface glia causes ultrastructural changes, albeit without compromising the integrity of the barrier. Supporting a role for endocytic trafficking in sleep, a screen of Rab GTPases identifies sleep-modulating effects of the recycling endosome Rab11 in surface glia. We also find that endocytosis is increased in BBB glia during sleep and reflects sleep need. We propose that endocytic trafficking through the BBB represents a function of sleep.
Collapse
Affiliation(s)
- Gregory Artiushin
- Neuroscience Graduate GroupPerelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Shirley L Zhang
- Howard Hughes Medical InstitutePerelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Hervé Tricoire
- Laboratory of Degenerative Processes, Stress and AgingUMR8251, Université Paris DiderotParisFrance
| | - Amita Sehgal
- Neuroscience Graduate GroupPerelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
- Howard Hughes Medical InstitutePerelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| |
Collapse
|
9
|
Sex Differences in Drosophila melanogaster Heterochromatin Are Regulated by Non-Sex Specific Factors. PLoS One 2015; 10:e0128114. [PMID: 26053165 PMCID: PMC4459879 DOI: 10.1371/journal.pone.0128114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/22/2015] [Indexed: 12/26/2022] Open
Abstract
The eukaryotic genome is assembled into distinct types of chromatin. Gene-rich euchromatin has active chromatin marks, while heterochromatin is gene-poor and enriched for silencing marks. In spite of this, genes native to heterochromatic regions are dependent on their normal environment for full expression. Expression of genes in autosomal heterochromatin is reduced in male flies mutated for the noncoding roX RNAs, but not in females. roX mutations also disrupt silencing of reporter genes in male, but not female, heterochromatin, revealing a sex difference in heterochromatin. We adopted a genetic approach to determine how this difference is regulated, and found no evidence that known X chromosome counting elements, or the sex determination pathway that these control, are involved. This suggested that the sex chromosome karyotype regulates autosomal heterochromatin by a different mechanism. To address this, candidate genes that regulate chromosome organization were examined. In XX flies mutation of Topoisomerase II (Top2), a gene involved in chromatin organization and homolog pairing, made heterochromatic silencing dependent on roX, and thus male-like. Interestingly, Top2 also binds to a large block of pericentromeric satellite repeats (359 bp repeats) that are unique to the X chromosome. Deletion of X heterochromatin also makes autosomal heterochromatin in XX flies dependent on roX and enhances the effect of Top2 mutations, suggesting a combinatorial action. We postulate that Top2 and X heterochromatin in Drosophila comprise a novel karyotype-sensing pathway that determines the sensitivity of autosomal heterochromatin to loss of roX RNA.
Collapse
|
10
|
Hindle SJ, Bainton RJ. Barrier mechanisms in the Drosophila blood-brain barrier. Front Neurosci 2014; 8:414. [PMID: 25565944 PMCID: PMC4267209 DOI: 10.3389/fnins.2014.00414] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 11/24/2014] [Indexed: 12/12/2022] Open
Abstract
The invertebrate blood-brain barrier (BBB) field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through G-protein coupled receptor signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate BBB has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many BBB mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the BBB can govern whole animal physiologies. This includes novel functions of BBB gap junctions in orchestrating synchronized neuroblast proliferation, and of BBB secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate BBB anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.
Collapse
Affiliation(s)
- Samantha J Hindle
- Department of Anesthesia and Perioperative Care, University of California, San Francisco San Francisco, CA, USA
| | - Roland J Bainton
- Department of Anesthesia and Perioperative Care, University of California, San Francisco San Francisco, CA, USA
| |
Collapse
|
11
|
Limmer S, Weiler A, Volkenhoff A, Babatz F, Klämbt C. The Drosophila blood-brain barrier: development and function of a glial endothelium. Front Neurosci 2014; 8:365. [PMID: 25452710 PMCID: PMC4231875 DOI: 10.3389/fnins.2014.00365] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/23/2014] [Indexed: 01/01/2023] Open
Abstract
The efficacy of neuronal function requires a well-balanced extracellular ion homeostasis and a steady supply with nutrients and metabolites. Therefore, all organisms equipped with a complex nervous system developed a so-called blood-brain barrier, protecting it from an uncontrolled entry of solutes, metabolites or pathogens. In higher vertebrates, this diffusion barrier is established by polarized endothelial cells that form extensive tight junctions, whereas in lower vertebrates and invertebrates the blood-brain barrier is exclusively formed by glial cells. Here, we review the development and function of the glial blood-brain barrier of Drosophila melanogaster. In the Drosophila nervous system, at least seven morphologically distinct glial cell classes can be distinguished. Two of these glial classes form the blood-brain barrier. Perineurial glial cells participate in nutrient uptake and establish a first diffusion barrier. The subperineurial glial (SPG) cells form septate junctions, which block paracellular diffusion and thus seal the nervous system from the hemolymph. We summarize the molecular basis of septate junction formation and address the different transport systems expressed by the blood-brain barrier forming glial cells.
Collapse
Affiliation(s)
- Stefanie Limmer
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Astrid Weiler
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Anne Volkenhoff
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Felix Babatz
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| | - Christian Klämbt
- Institut für Neuro- und Verhaltensbiologie, Universität Münster Münster, Germany
| |
Collapse
|
12
|
Lee DA, Yoo S, Pak T, Salvatierra J, Velarde E, Aja S, Blackshaw S. Dietary and sex-specific factors regulate hypothalamic neurogenesis in young adult mice. Front Neurosci 2014; 8:157. [PMID: 24982613 PMCID: PMC4056383 DOI: 10.3389/fnins.2014.00157] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/26/2014] [Indexed: 11/26/2022] Open
Abstract
The hypothalamus is the central regulator of a broad range of homeostatic and instinctive physiological processes, such as the sleep-wake cycle, food intake, and sexually dimorphic behaviors. These behaviors can be modified by various environmental and physiological cues, although the molecular and cellular mechanisms that mediate these effects remain poorly understood. Recently, it has become clear that both the juvenile and adult hypothalamus exhibit ongoing neurogenesis, which serve to modify homeostatic neural circuitry. In this report, we share new findings on the contributions of sex-specific and dietary factors to regulating neurogenesis in the hypothalamic mediobasal hypothalamus, a recently identified neurogenic niche. We report that high fat diet (HFD) selectively activates neurogenesis in the median eminence (ME) of young adult female but not male mice, and that focal irradiation of the ME in HFD-fed mice reduces weight gain in females but not males. These results suggest that some physiological effects of high fat diet are mediated by the stimulation of ME neurogenesis in a sexually dimorphic manner. We discuss these results in the context of recent advances in understanding the cellular and molecular mechanisms that regulate neurogenesis in postnatal and adult hypothalamus.
Collapse
Affiliation(s)
- Daniel A Lee
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Division of Biology and Biomedical Engineering, California Institute of Technology Pasadena, CA, USA
| | - Sooyeon Yoo
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Thomas Pak
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Juan Salvatierra
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Esteban Velarde
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Susan Aja
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Institute for Cell Engineering, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Ophthalmology, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Center for High-Throughput Biology, Johns Hopkins University School of Medicine Baltimore, MD, USA
| |
Collapse
|
13
|
Lu B, Zelle KM, Seltzer R, Hefetz A, Ben-Shahar Y. Feminization of pheromone-sensing neurons affects mating decisions in Drosophila males. Biol Open 2014; 3:152-60. [PMID: 24463366 PMCID: PMC3925318 DOI: 10.1242/bio.20147369] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The response of individual animals to mating signals depends on the sexual identity of the individual and the genetics of the mating targets, which represent the mating social context (social environment). However, how social signals are sensed and integrated during mating decisions remains a mystery. One of the models for understanding mating behaviors in molecular and cellular terms is the male courtship ritual in the fruit fly (Drosophila melanogaster). We have recently shown that a subset of gustatory receptor neurons (GRNs) that are enriched in the male appendages and express the ion channel ppk23 play a major role in the initiation and maintenance of male courtship via the perception of cuticular contact pheromones, and are likely to represent the main chemosensory pathway that influences mating decisions by males. Here we show that genetic feminization of ppk23-expressing GRNs in male flies resulted in a significant increase in male-male sexual attraction without an apparent impact on sexual attraction to females. Furthermore, we show that this increase in male-male sexual attraction is sensory specific, which can be modulated by variable social contexts. Finally, we show that feminization of ppk23-expressing sensory neurons lead to major transcriptional shifts, which may explain the altered interpretation of the social environment by feminized males. Together, these data indicate that the sexual cellular identity of pheromone sensing GRNs plays a major role in how individual flies interpret their social environment in the context of mating decisions.
Collapse
Affiliation(s)
- Beika Lu
- Department of Biology, Washington University in St Louis, MO 63130, USA
| | | | | | | | | |
Collapse
|