Biology subjects

Armstrong, A. R.

Publications and source records attributed to Armstrong, A. R..

4 recordsLinked to original sources

bioRxiv2026

Fat body driver expression report across Drosophila melanogaster tissues and sex

Drosophila melanogaster serves as a valuable model system for advancing our understanding of adipose tissue given its analogous organ systems, conserved metabolic, endocrine, and nutrient-sensing functions, and well-established genetic tools. Among the most widely used genetic tools is the Gal4/UAS system. Several Gal4 driver lines are reported to control expression in the D. melanogaster fat body, but secondary expression sites and responses to physiological changes have not been fully characterized. In this report, we describe fluorescent reporter expression for 31 fat body Gal4 transgenic lines in larvae and adults, males and females, and in multiple tissues, brain, indirect flight muscle, gut, ovary, testis, and fat body. This screen highlights expression differences with respect to level, sex, and stage. Moreover, we find that several lines drive expression in tissues that had not been previously described. Together, we present a comprehensive expression atlas of fat body driver lines, serving as a resource to advance adipose tissue research.

cell biology↗

bioRxiv2024

Translation components in adult Drosophila melanogaster adipocytes regulate the ovarian germline stem cell lineage

Adult stem cells, which support tissue homeostasis and damage repair, are influenced by whole organism physiology. Dietary input has a major impact on the stem cell supported ovary in Drosophila melanogaster females, appropriately matching reproductive output to nutrient availability. Previous work has shown that inter-organ communication plays a role in modulating the ovarian response to diet. Specifically, amino acid sensing by the adipose tissue remotely controls germline stem cells and their progeny. While we have shown that activation of the amino acid response pathway, a part of the integrated stress response, and mTOR signaling in adipocytes impacts germline stem cell maintenance and ovulation, it is unclear how downstream signaling mediates these responses. Here, using a combination of genetic and cell biological tools, we show that regulation of translation in adult adipocytes impacts the ovarian germline stem cell lineage, from stem cell maintenance to ovulation of mature oocytes. This work strongly suggests that the adipose tissue produces specific factors to control stem cell activity in the ovary and highlights how inter-organ communication underlies organismal physiological responses to diet.

physiology↗

bioRxiv2024

Improved whole-mount immunofluorescence protocol for consistent and robust labeling of adult Drosophila melanogaster adipose tissue

Energy storage and endocrine functions of the Drosophila fat body make it an excellent model for elucidating mechanisms that underlie physiological and pathophysiological organismal metabolism. Combined with Drosophilas robust genetic and immunofluorescence microscopy toolkits, studies of Drosophila fat body function are ripe for cell biological analysis. Unlike the larval fat body, which is easily removed as a single, cohesive sheet of tissue, isolating intact adult fat body proves to be more challenging, thus hindering consistent immunofluorescence labeling even within a single piece of adipose tissue. Here, we describe an improved approach to handling Drosophila abdomens that ensures full access of the adult fat body to solutions generally used in immunofluorescence labeling protocols. In addition, we assess the quality of fluorescence reporter expression and antibody immunoreactivity in response to variations in fixative type, fixation incubation time, and detergent used for cellular permeabilization. Overall, we provide several recommendations for steps in a whole mount staining protocol that results in consistent and robust immunofluorescence labeling of the adult Drosophila fat body. SUMMARY STATEMENTOptimization of adult Drosophila fat body fluorescence microscopy via modifications of tissue handling, fixation, and permeabilization steps in a whole mount immunolabeling protocol.

cell biology↗

bioRxiv2020

Gut Microbe-Targeted Choline Trimethylamine Lyase Inhibition Improves Obesity Via Rewiring of Host Circadian Rhythms

Obesity has repeatedly been linked to reorganization of the gut microbiome, yet to this point obesity therapeutics have been targeted exclusively toward the human host. Here we show that gut microbe-targeted inhibition of the trimethylamine N-oxide (TMAO) pathway protects mice against the metabolic disturbances associated with diet-induced obesity (DIO) or leptin deficiency (ob/ob). Small molecule inhibition of the gut microbial enzyme choline TMA-lyase (CutC) does not reduce food intake, but is instead associated with beneficial remodeling of the gut microbiome, improvement in glucose tolerance, and enhanced energy expenditure. We also show that CutC inhibition is associated with reorganization of host circadian control of both phosphatidylcholine and energy metabolism. This study underscores the relationship between microbe and host metabolism, and provides evidence that gut microbe-derived trimethylamine (TMA) is a key regulator of the host circadian clock. This work also demonstrates that gut microbe-targeted enzyme inhibitors have untapped potential as anti-obesity therapeutics.

physiology↗