Wengen's hidden powers: ROS triggers a TNFR-dependent tissue regenerative pathway in Drosophila.

While the role of the Tumor necrosis factor-α (referred to as TNF here) as a key mediator of pro-inflammatory and immune responses is well-established, non-pathological functions of the TNF-TNF receptor (TNFR) signaling are less explored. In this issue of The EMBO Journal, Esteban-Collado et al, (2024) describe a TNF independent, pro-survival role of the TNFR Wengen during damage-induced tissue regeneration.

Drosophila activins adapt gut size to food intake and promote regenerative growth.

Rapidly renewable tissues adapt different strategies to cope with environmental insults. While tissue repair is associated with increased intestinal stem cell (ISC) proliferation and accelerated tissue turnover rates, reduced calorie intake triggers a homeostasis-breaking process causing adaptive resizing of the gut. Here we show that activins are key drivers of both adaptive and regenerative growth.

Drosophila TNF/TNFRs: At the crossroad between metabolism, immunity, and tissue homeostasis.

Tumor necrosis factor (TNF)-α is a highly conserved proinflammatory cytokine with important functions in immunity, tissue repair, and cellular homeostasis. Due to the simplicity of the Drosophila TNF-TNF receptor (TNFR) system and a broad genetic toolbox, the fly has played a pivotal role in deciphering the mechanisms underlying TNF-mediated physiological and pathological functions. In this review, we summarize the recent advances in our understanding of how local and systemic sources of Egr/TNF contribute to its antitumor and tumor-promoting properties, and its emerging functions in adaptive growth responses, sleep regulation, and adult tissue homeostasis.

The Drosophila tumor necrosis factor receptor, Wengen, couples energy expenditure with gut immunity.

It is well established that tumor necrosis factor (TNF) plays an instrumental role in orchestrating the metabolic disorders associated with late stages of cancers. However, it is not clear whether TNF/TNF receptor (TNFR) signaling controls energy homeostasis in healthy individuals. Here, we show that the highly conserved Drosophila TNFR, Wengen (Wgn), is required in the enterocytes (ECs) of the adult gut to restrict lipid catabolism, suppress immune activity, and maintain tissue homeostasis.

A Dilp8-dependent time window ensures tissue size adjustment in Drosophila.

The control of organ size mainly relies on precise autonomous growth programs. However, organ development is subject to random variations, called developmental noise, best revealed by the fluctuating asymmetry observed between bilateral organs. The developmental mechanisms ensuring bilateral symmetry in organ size are mostly unknown.

Drosophila TNFRs Grindelwald and Wengen bind Eiger with different affinities and promote distinct cellular functions.

The Drosophila tumour necrosis factor (TNF) ligand-receptor system consists of a unique ligand, Eiger (Egr), and two receptors, Grindelwald (Grnd) and Wengen (Wgn), and therefore provides a simple system for exploring the interplay between ligand and receptors, and the requirement for Grnd and Wgn in TNF/Egr-mediated processes. Here, we report the crystallographic structure of the extracellular domain (ECD) of Grnd in complex with Egr, a high-affinity hetero-hexameric assembly reminiscent of human TNF:TNFR complexes. We show that ectopic expression of Egr results in internalisation of Egr:Grnd complexes in vesicles, a step preceding and strictly required for Egr-induced apoptosis.

The Drosophila gut: A gatekeeper and coordinator of organism fitness and physiology.

Multicellular organisms have evolved organs and tissues with highly specialized tasks. For instance, nutrients are assimilated by the gut, sensed, processed, stored, and released by adipose tissues and liver to provide energy consumed by peripheral organ activities. The function of each organ is modified by local clues and systemic signals derived from other organs to ensure a coordinated response accommodating the physiological needs of the organism.

Simple ions control the elasticity of calcite gels via interparticle forces.

Suspensions of calcite in water are employed in many industrial fields such as paper filling, pharmaceutics or heritage conservation. Whereas organics are generally used to tune the rheological properties of the paste, we also expect simple ions to be able to control the suspension rheology via the interparticle forces. We have thus investigated the impact of calcium, sodium and hydroxide ions on the elasticity of a colloidal gel of nanocalcite.

Inter-Organ Growth Coordination Is Mediated by the Xrp1-Dilp8 Axis in Drosophila.

How organs scale with other body parts is not mechanistically understood. We have addressed this question using the Drosophila imaginal disc model. When the growth of one disc domain is perturbed, other parts of the disc and other discs slow down their growth, maintaining proper inter-disc and intra-disc proportions.

Hollow Rims from Water Drop Evaporation on Salt Substrates.

We report on the observation of thin salt shells that form at the periphery of evaporating pure water drops on salt. Shell shapes range from rings of inclined walls to hollow toroidal rims. We interpret this phenomenon as a consequence of a molecular coffee-stain effect by which the dissolved salt is advected toward the pinned contact line where an increased evaporation takes place.

A Drosophila Tumor Suppressor Gene Prevents Tonic TNF Signaling through Receptor N-Glycosylation.

Drosophila tumor suppressor genes have revealed molecular pathways that control tissue growth, but mechanisms that regulate mitogenic signaling are far from understood. Here we report that the Drosophila TSG tumorous imaginal discs (tid), whose phenotypes were previously attributed to mutations in a DnaJ-like chaperone, are in fact driven by the loss of the N-linked glycosylation pathway component ALG3. tid/alg3 imaginal discs display tissue growth and architecture defects that share characteristics of both neoplastic and hyperplastic mutants.

[Some insulins to orchestrate growth].

Body size is an intrinsic property of living organisms that is intimately linked to the developmental program to produce fit individuals with proper proportions. Final size is the result of both genetic determinants and sophisticated mechanisms adapting size to available resources. Even though organs grow according to autonomous programs, some coordination mechanisms ensure that the different body parts adjust their growth with the rest of the body.

Studying radiolytic ageing of nuclear power plant electric cables with FTIR spectroscopy.

Due to the willingness to extend the nuclear power plants length of life, it is of prime importance to understand long term ageing effect on all constitutive materials. For this purpose gamma-irradiation effects on insulation of instrumentation and control cables are studied. Mid-infrared spectroscopy and principal components analysis (PCA) were used to highlight molecular modifications induced by gamma-irradiation under oxidizing conditions.

Elasticity and yielding of a calcite paste: scaling laws in a dense colloidal suspension.

We address the mechanical characterization of a calcite paste as a model system to investigate the relation between the microstructure and macroscopic behavior of colloidal suspensions. The ultimate goal is to achieve control of the elastic and yielding properties of calcite which will prove valuable in several domains, from paper coating to paint manufacture and eventually in the comprehension and control of the mechanical properties of carbonate rocks. Rheological measurements have been performed on calcite suspensions over a wide range of particle concentrations.

A FTIR/chemometrics approach to characterize the gamma radiation effects on iodine/epoxy-paint interactions in Nuclear Power Plants.

The effects of radiation on polymeric materials are a topic of concern in a wide range of industries including the sterilization, and the nuclear power industry. While much work has concentrated on systems like polyolefins that are radiation sterilized, some work has been done on epoxy systems. The epoxy system studied is an epoxy/amine paint which is representative of the paint that covers the inner surfaces of the French nuclear reactor containment buildings.

The Hippo signalling pathway coordinates organ growth and limits developmental variability by controlling dilp8 expression.

Coordination of organ growth during development is required to generate fit individuals with fixed proportions. We recently identified Drosophila Dilp8 as a key hormone in coupling organ growth with animal maturation. In addition, dilp8 mutant flies exhibit elevated fluctuating asymmetry (FA) demonstrating a function for Dilp8 in ensuring developmental stability.

The Alkaline Dissolution Rate of Calcite.

Due to the widespread presence of calcium carbonate on Earth, several geochemical systems, among which is the global CO2 cycle, are controlled to a large extent by the dissolution and precipitation of this mineral. For this reason, the dissolution of calcite has been thoroughly investigated for decades. Despite this intense activity, a consensual value of the dissolution rate of calcite has not been found yet.

Gene expression profiling in necrotizing enterocolitis reveals pathways common to those reported in Crohn's disease.

Background: Necrotizing enterocolitis (NEC) is the most frequent life-threatening gastrointestinal disease experienced by premature infants in neonatal intensive care units. The challenge for neonatologists is to detect early clinical manifestations of NEC. One strategy would be to identify specific markers that could be used as early diagnostic tools to identify preterm infants most at risk of developing NEC or in the event of a diagnostic dilemma of suspected disease.

Drosophila Lgr3 Couples Organ Growth with Maturation and Ensures Developmental Stability.

Early transplantation and grafting experiments suggest that body organs follow autonomous growth programs [1-3], therefore pointing to a need for coordination mechanisms to produce fit individuals with proper proportions. We recently identified Drosophila insulin-like peptide 8 (Dilp8) as a relaxin and insulin-like molecule secreted from growing tissues that plays a central role in coordinating growth between organs and coupling organ growth with animal maturation [4, 5]. Deciphering the function of Dilp8 in growth coordination relies on the identification of the receptor and tissues relaying Dilp8 signaling.

The Drosophila TNF receptor Grindelwald couples loss of cell polarity and neoplastic growth.

Disruption of epithelial polarity is a key event in the acquisition of neoplastic growth. JNK signalling is known to play an important part in driving the malignant progression of many epithelial tumours, although the link between loss of polarity and JNK signalling remains elusive. In a Drosophila genome-wide genetic screen designed to identify molecules implicated in neoplastic growth, we identified grindelwald (grnd), a gene encoding a transmembrane protein with homology to members of the tumour necrosis factor receptor (TNFR) superfamily.

Influence of fine particles on the stability of a humid granular pile.

We have investigated by rotating drum experiments the influence of a small amount of fine particles on the stability of a granular heap. The fine particles are shown to have a strong and ambivalent influence. For low fine particle content, the heap destabilizes by avalanches, and the fine particles tend to fluidize the heap.

Coordination of organ growth: principles and outstanding questions from the world of insects.

In animal species undergoing determinate growth, the making of a full-size adult body requires a series of coordinated growth events culminating in the cessation of growth that precedes sexual maturation. The merger between physiology and genetics now coming to pass in the Drosophila model allows us to decipher these growth events with an unsurpassed level of sophistication. Here, we review several coordination mechanisms that represent fundamental aspects of growth control: adaptation of growth to environmental cues, interorgan coordination, and the coordination of growth with developmental transitions.