Publications by authors named "Aki Ejima"

Article Synopsis
  • The IL-7Rα gene is crucial for T cell functions, and a specific noncoding region called CNS9 was identified as a key enhancer regulating its expression in γδ T cells, particularly Vγ4+ cells.
  • Mutations in CNS9 that affect its enhancer activity lead to reduced IL-7Rα levels in Vγ4+ γδ T cells, which in turn decreases their numbers and production of IL-17A in adipose tissue.
  • This decrease in IL-17A correlates with lower IL-33 levels and fewer regulatory T cells, linking CNS9's function to adipose tissue homeostasis and potentially impacting the development of type 2 diabetes.
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Article Synopsis
  • Group 2 innate lymphoid cells (ILC2s) play a key role in combating parasites and maintaining tissue health, but factors limiting their function are not well understood.
  • Research indicates that CD45, a protein important for T cell development, negatively regulates the proliferation and activity of ILC2s in a way that impacts their function.
  • The study also shows that CD45 helps control type 2 inflammation in the lungs by interacting with ILC2s, suggesting it may be a potential target for treating lung inflammation and fibrosis.
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Article Synopsis
  • Asthma prevalence is higher in females than males after adolescence, and the reasons for this difference are not fully understood.
  • Research on mice lacking androgen (AR) and estrogen receptors (ER) showed that AR-deficient males had more severe allergic airway inflammation, while ER-deficient females had inflammation similar to control females.
  • Findings suggest that androgen signaling reduces cytokine production in T cells and influences genes related to asthma, particularly by regulating DUSP-2, which may help explain the observed sex bias in asthma rates.
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Article Synopsis
  • Steroid hormones like glucocorticoids, androgens, and estrogens significantly impact the immune system, with distinct roles for each type of hormone.
  • Glucocorticoids are known for their anti-inflammatory effects, suppressing innate immunity while enhancing adaptive immunity by promoting T cell functions.
  • Androgens help regulate immune responses by inhibiting certain immune cell activities and supporting regulatory T cells, which can reduce allergic reactions, while research on the role of estrogens in immunity is still ongoing.
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Glucocorticoids (GCs) are a class of steroid hormones secreted from the adrenal cortex. Their production is controlled by circadian rhythm and stress, the latter of which includes physical restraint, hunger, and inflammation. Importantly, GCs have various effects on immunity, metabolism, and cognition, including pleiotropic effects on the immune system.

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Animals perform a series of actions in a fixed order during ritualistic innate behaviors. Although command neurons and sensory pathways responding to external stimuli that trigger these behaviors have been identified, how each action is induced in a fixed order in response to multimodal sensory stimuli remains unclear. Here, the sexually dimorphic lateral antennal lobe tract projection neuron 4 (lPN4) in male mediates the expression of a fixed behavioral action pattern at the beginning of the courtship ritual, in which a male taps a female body and then extends a wing unilaterally to produce a courtship song.

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A male-specific component, 11-cis-vaccenyl acetate (cVA) works as an anti-aphrodisiac pheromone in Drosophila melanogaster. The presence of cVA on a male suppresses the courtship motivation of other males and contributes to suppression of male-male homosexual courtship, while the absence of cVA on a female stimulates the sexual motivation of nearby males and enhances the male-female interaction. However, little is known how a male distinguishes the presence or absence of cVA on a target fly from either self-produced cVA or secondhand cVA from other males in the vicinity.

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Pleiotropic actions of the male pheromone cis-vaccenyl acetate in Drosophila melanogaster.

J Comp Physiol A Neuroethol Sens Neural Behav Physiol

September 2015

The male-specific lipid, cis-vaccenyl acetate (cVA) has multiple functions in intra-species communication in Drosophila melanogaster. The presence of cVA in a male suppresses courtship motivation of other males and averts male-male courtship. Meanwhile, aggression behaviors between males are promoted by a high amount of cVA caused by increased densities of male flies.

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Mate selection is critical to ensuring the survival of a species. In the fruit fly, Drosophila melanogaster, genetic and anatomical studies have focused on mate recognition and courtship initiation for decades. This model system has proven to be highly amenable for the study of neural systems controlling the decision making process.

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The antennal lobe (AL) is the primary olfactory center in insect brains. It receives sensory input from the olfactory sensory neurons (OSNs) and sends, through its projection neurons (PNs), reformatted output to secondary olfactory centers, including the mushroom body (MB) calyx and the lateral horn (LH) in the protocerebrum. By injecting dye into the AL of wild-type Drosophila, we identified previously unknown direct pathways between the AL and the ventrolateral, superior medial, and posterior lateral protocerebra.

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Genetic causes for disturbances of locomotor behavior can be due to muscle, peripheral neuron, or central nervous system pathologies. The Drosophila melanogaster homolog of human CASK (also known as caki or camguk) is a molecular scaffold that has been postulated to have roles in both locomotion and plasticity. These conclusions are based on studies using overlapping deficiencies that largely eliminate the entire CASK locus, but contain additional chromosomal aberrations as well.

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Mechanisms for identifying appropriate mating partners are critical for species propagation. In many species, the male uses multiple sensory modalities to search for females and to subsequently determine if they are fit and receptive. Males can also use the information they acquire in this process to change their courtship behavior and reduce courtship of classes of targets that are inappropriate or unreceptive.

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Mechanisms for identifying appropriate mating partners are required for any species to survive. In many types of animals, males employ multiple sensory modalities to initially search for females and to subsequently determine if they are fit and/or receptive. In this paper we will detail the multiple types of sensory information that are used to initiate and drive courtship in Drosophila melanogaster and discuss the importance of context in the interpretation of chemosensory cues.

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Finding a mating partner is a critical task for many organisms. It is in the interest of males to employ multiple sensory modalities to search for females. In Drosophila melanogaster, vision is thought to be the most important courtship stimulating cue at long distance, while chemosensory cues are used at relatively short distance.

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Reproductive behavior in Drosophila has both stereotyped and plastic components that are driven by age- and sex-specific chemical cues. Males who unsuccessfully court virgin females subsequently avoid females that are of the same age as the trainer. In contrast, males trained with mature mated females associate volatile appetitive and aversive pheromonal cues and learn to suppress courtship of all females.

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INTRODUCTIONIn Drosophila melanogaster, as in many other animals, courtship is a series of stereotypical behaviors carried out by a male responding to multimodal signals. Because different experimental conditions can engage distinct sensory modalities that affect male behavior, courtship experiments need to be carefully designed. There are several ways to manipulate sensory inputs to the test male.

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Background: Associative memory formation requires that animals choose predictors for experiences they need to remember. When an artificial odor is paired with an aversive experience, that odor becomes the predictor. In more natural settings, however, animals can have multiple salient experiences that need to be remembered and prioritized.

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To better understand the genetic bases of postmating responses in Drosophila melanogaster females, we screened a collection of P{GS} insertion lines and identified two insertions in sarah (sra), whose misexpression in the nervous system induced high levels of ovulation in virgins. The gene sra encodes a protein similar to human Down syndrome critical region 1 (DSCR1). The ovulation phenotype was reproduced in transgenic virgins expressing UAS-sra in the nervous system.

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Understanding the complex array of genes, proteins and cells involved in learning and memory is a major challenge for neuroscientists. Using the genetically powerful model system, Drosophila melanogaster, and its well-studied courtship behavior, investigators have begun to delineate essential elements of associative and nonassociative behavioral plasticity. Advances in transgenic tools and developments in behavioral assays have increased the power of studying courtship learning in the fruit fly.

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