Smoking flies: testing the effect of tobacco cigarettes on heart function of Drosophila melanogaster

Effects of cocaine, nicotine, and marijuana exposure in Drosophila Melanogaster development: A systematic review and meta-analysis

Abuse-related drug usage is a public health issue. Drosophila melanogaster has been used as an animal model to study the biological effects of these psychoactive substances in preclinical studies. Our objective in this review is to evaluate the adverse effects produced by cocaine, nicotine, and marijuana during the development of D. melanogaster. We searched experimental studies in which D. melanogaster was exposed to these three psychoactive drugs in seven online databases up to January 2023. Two reviewers independently extracted the data. Fifty-one studies met eligibility criteria and were included in the data extraction: nicotine (n = 26), cocaine (n = 20), and marijuana (n = 5). Fifteen studies were eligible for meta-analysis. Low doses (∼0.6 mM) of nicotine increased locomotor activity in fruit flies, while high doses (≥3 mM) led to a decrease. Similarly, exposure to cocaine increased locomotor activity, resulting in decreased climbing response in D. melanogaster. Studies with exposure to marijuana did not present a profile for our meta-analysis. However, this drug has been less associated with locomotor changes, but alterations in body weight and fat content and changes in cardiac function. Our analyses have shown that fruit flies exposed to drugs of abuse during different developmental stages, such as larvae and adults, exhibit molecular, morphological, behavioral, and survival changes that are dependent on the dosage. These phenotypes resemble the adverse effects of psychoactive substances in clinical medicine.

The effect of cigarette smoke extract exposure on the size and sexual behaviour of Drosophila melanogaster

Drosophila melanogaster is a widely used animal model in human diseases and to date it has not been applied to the study of the impact of tobacco use on human sexual function. Hence, this report examines the effects of different concentrations of cigarette smoke extract (CSE) exposure on the size and sexual behavior of D. melanogaster. Wild-type flies were held in vials containing CSE-infused culture media at concentrations of 10%, 25%, and 50% for three days, and their offspring were reared under the same conditions before measuring their body size and mating behavior. CSE exposure during development reduced the tibia length and body mass of emerging adult flies and prolonged the time required for successful courtship copulation success, while courtship behaviors (wing extension, tapping, abdomen bending, attempted copulation) remained largely unchanged. Our findings indicate that CSE exposure negatively affects the development of flies and their subsequent reproductive success. Future experiments should investigate the CSE effect on male female fertility.

Systematic Mapping and Review of Landscape Fire Smoke (LFS) Exposure Impacts on Insects

Landscape fire activity is changing in many regions because of climate change. Smoke emissions from landscape fires contain many harmful air pollutants, and beyond the potential hazard posed to human health, these also have ecological impacts. Insects play essential roles in most ecosystems worldwide, and some work suggests they may also be sensitive to smoke exposure. There is therefore a need for a comprehensive review of smoke impacts on insects. We systematically reviewed the scientific literature from 1930 to 2022 to synthesize the current state of knowledge of the impacts of smoke exposure from landscape fires on the development, behavior, and mortality of insects. We found: (1) 42 relevant studies that met our criteria, with 29% focused on the United States of America and 19% on Canada; (2) of these, 40 insect species were discussed, all of which were sensitive to smoke pollution; (3) most of the existing research focuses on how insect behavior responds to landscape fire smoke (LFS); (4) species react differently to smoke exposure, with for example some species being attracted to the smoke (e.g., some beetles) while others are repelled (e.g., some bees). This review consolidates the current state of knowledge on how smoke impacts insects and highlights areas that may need further investigation. This is particularly relevant since smoke impacts on insect communities will likely worsen in some areas due to increasing levels of biomass burning resulting from the joint pressures of climate change, land use change, and more intense land management involving fire.

Prediction and enrichment analyses of the Homo sapiens-Drosophila melanogaster COPD-related orthologs

The significant similarities in airway epithelial cells between mammals and the fruit fly Drosophila melanogaster have rendered the latter an important model organism for studies of chronic inflammatory lung diseases. Focusing on the chronic obstructive pulmonary disease (COPD), we here mapped human gene orthologs associated with this disease in D. melanogaster to identify functionally equivalent genes for immediate, further screening with the fruit fly model. The DIOPT-DIST tool was accessed for the prediction of the COPD-associated orthologs between humans and Drosophila. Enrichment analyses with respect to pathways of the retrieved functional homologs were performed using the ToppFun and FlyMine tools, identifying 73 unique human genes as well as 438 fruit fly genes. The ToppFun analysis verified that the human gene list is associated with COPD phenotypes. Further, the FlyMine investigation highlighted that the Drosophila genes are functionally connected mainly with the 'ABC-family proteins mediated transport' and the 'beta-catenin independent WNT signaling pathway'. These results suggest an evolutionarily conserved role towards responses to inhaled toxicants and CO₂ in both species. We reason that the predicted orthologous genes should be further studied in the Drosophila models of cigarette smoke-induced COPD.

A low-cost Portable Device to Deliver Smoke, Volatile or Vaporized Substances to Drosophila melanogaster, Useful for Research and/or Educational Assays

Drosophila melanogaster has been used to test drugs of abuse, substances with potential benefits for medical purposes, as well as contaminants and hazardous volatile compounds. This model has also been used for the characterization of behavioral changes, physiopathological consequences, and subcellular mechanisms of the use of cocaine, methamphetamines, ethanol, nicotine, cannabinoids, toluene, and other airborne volatile organic compounds. When testing these substances, routes of administration are important to define. Admixing the test compounds with water or food is one suitable option in many cases, but the inhalation route is especially suitable when the administration of one or more volatile compounds is desired. One advantage of the administration of substances via the inhalation route is its rapid exchange and distribution throughout the cuticle and the tracheal system. In addition, this route allows treating a large group of individuals simultaneously. Moreover, the inhalation route is frequently used to administer different drugs to humans. A good model system shares physiology and molecular pathways with humans, and D. melanogaster possesses almost 75% homologous genes associated with human diseases. Methodologies to deliver the abovementioned substances usually include customized devices. Herein, we focus on the development of a low-cost customized device useful to deliver smoke or vaporizable compounds to D. melanogaster. This approach might be applied for acute or chronic exposure to vaporized substances. In particular, our device was utilized for testing cigarette smoke and vaporized cannabis extract on cardiac performance of adult individuals during chronic treatment. We are describing how to set up this low-cost portable device, useful for research and/or educational assays, taking advantage of the amenability of D. melanogaster to test different compounds in relatively short periods, and especially including a large number of individuals at the same time. Graphic abstract: Custom-made device useful for inhalation pathway assays in Drosophila melanogaster.

Drosophila Trachea as a Novel Model of COPD

COPD, a chronic obstructive pulmonary disease, is one of the leading causes of death worldwide. Clinical studies and research in rodent models demonstrated that failure of repair mechanisms to cope with increased ROS and inflammation in the lung leads to COPD. Despite this progress, the molecular mechanisms underlying the development of COPD remain poorly understood, resulting in a lack of effective treatments. Thus, an informative, simple model is highly valued and desired. Recently, the cigarette smoke-induced Drosophila COPD model showed a complex set of pathological phenotypes that resemble those seen in human COPD patients. The Drosophila trachea has been used as a premier model to reveal the mechanisms of tube morphogenesis. The association of these mechanisms to structural changes in COPD can be analyzed by using Drosophila trachea. Additionally, the timeline of structural damage, ROS, and inflammation can be studied in live organisms using fluorescently-tagged proteins. The related function of human COPD genes identified by GWAS can be screened using respective fly homologs. Finally, the Drosophila trachea can be used as a high-throughput drug screening platform to identify novel treatments for COPD. Therefore, Drosophila trachea is an excellent model that is complementary to rodent COPD models.

First person – Manuela Santalla

First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping early-career researchers promote themselves alongside their papers. Manuela Santalla is first author on ‘Testing the effect of tobacco cigarettes on heart function of Drosophila melanogaster’, published in BiO. Manuela is a postdoc in the lab of Dr. Paola Ferrero, interested in understanding how the heart works. She studies the physiology of the heart of the fruit fly and how different conditions affect it.