Biology subjects

Donini, A.

Publications and source records attributed to Donini, A..

9 recordsLinked to original sources

bioRxiv2025

Impairment of the blood brain barrier accelerates a negative ultraslow potential in the locust CNS

Insects provide useful models for investigating evolutionarily conserved mechanisms underlying electrical events associated with brain injury and death. Spreading depolarizations (SD) are transient events that propagate through neuropil whereas the negative ultraslow potential (NUP) is sustained and reflects accumulating damage in the tissue. We used the locust, Locusta migratoria, to investigate ion homeostasis at the blood brain barrier (BBB) during SD and NUP induced by treatment with the Na+/K+-ATPase inhibitor, ouabain. We found that sustained SD caused by the metabolic inhibitor, sodium azide, was associated with a large reduction of K+ efflux through the BBB at ganglia (= grey matter) but not at connectives (= white matter). This was accompanied by a large increase in tissue resistivity but no conductance changes of identified motoneuron dendrites in the neuropil. Males recovered more slowly from ouabain-induced SD, as previously described for anoxic SD. Impairment of barrier functions of the BBB pharmacologically with cyclosporin A or DIDS, or by cutting nerve roots, accelerated the NUP, thus promoting earlier and more frequent SD, but had no effect on the temporal parameters of SD. We conclude that the mechanisms underlying onset and recovery of SD are minimally affected by the damage associated with the NUP. We suggest that future research using tissue-specific genetic approaches in Drosophila to target identified molecular structures of the BBB are likely to be fruitful. New and NoteworthyInhibition of the sodium pump in the locust CNS causes repetitive spreading depolarization (SD) and a negative ultraslow potential (NUP) providing a model for investigation of phenomena relevant to human health. We show that impairment of the blood brain barrier accelerates the NUP but has no impact on the trajectory of SD events. Hence, rapid mechanisms of onset and recovery of ion homeostasis occur against a background of slowly increasing neural damage. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=169 SRC="FIGDIR/small/648410v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1d8174corg.highwire.dtl.DTLVardef@1e1a57aorg.highwire.dtl.DTLVardef@13719a9org.highwire.dtl.DTLVardef@75b641_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

Bile Acids Serve As Endogenous Antagonists Of The Leukemia Inhibitory Factor (LIF) Receptor in Oncogenesis

The leukemia inhibitory factor (LIF) is member of IL-6 family of cytokines involved immune regulation, morphogenesis and oncogenesis. In cancer tissues, LIF binds a heterodimeric receptor (LIFR), formed by a LIFR{beta} subunit and glycoprotein(gp)130, promoting epithelial mesenchymal transition and cell growth. Bile acids are cholesterol metabolites generated at the interface of host metabolism and the intestinal microbiota. Here we demonstrated that bile acids serve as endogenous antagonist to LIFR in oncogenesis. The tissue characterization of bile acids content in non-cancer and cancer biopsy pairs from gastric adenocarcinomas (GC) demonstrated that bile acids accumulate within cancer tissues, with glyco-deoxycholic acid (GDCA) functioning as negative regulator of LIFR expression. In patient-derived organoids (hPDOs) from GC patients, GDCA reverses LIF-induced stemness and proliferation. In summary, we have identified the secondary bile acids as the first endogenous antagonist to LIFR supporting a development of bile acid-based therapies in LIF-mediated oncogenesis.

cancer biology↗

bioRxiv2022

Next generation sequencing analysis of gastric cancer identifies the leukemia inhibitory factor receptor (LIFR) as a driving factor in gastric cancer progression and as a predictor of poor prognosis

Gastric cancer (GC) is the third cause of cancer-related-death worldwide. Nevertheless, because GC screening programs are not cost-effective, most patients receive diagnosis in the advanced stages, when surgical options are limited because the presence of diffuse disease. Peritoneal dissemination occurs in approximately one third of patients with GC and is a strong predictor of poor outcome. Despite the clinical relevance, biological and molecular mechanisms underlying the formation of peritoneal metastasis in GC remain poorly defined. To investigate this point, we conducted a high-throughput sequencing of transcriptome expression in paired samples of normal and neoplastic gastric mucosa in 31 GC patients with or without peritoneal carcinomatosis. The RNAseq analysis led to the discovery of a group of highly upregulated or downregulated genes that were differentially modulated in patients with peritoneal disease in comparison to GC patients without peritoneal involvement. Among these genes the leukemia inhibitory factor receptor (LIFR) and the one cut domain family member (ONECUT)2 were the only two genes that predicted survival at univariate statistical analysis. Because LIFR was the highest regulated gene we have further assessed whether this receptor plays a mechanistic role in GC dissemination. For this purpose, we have first assessed the expression of LIF, a member of IL-6 cytokine family, and LIFR in GC cell lines. Our results demonstrate that exposure of MKN45 cells to LIF, promoted a concentration-dependent proliferation and epithelial-mesenchymal transition (EMT) as shown by modulation of E-cadherin/vimentin gene expression along with JAK and STAT 3 phosphorylation and acquisition of a migratory phenotype. These features were reversed by in vitro treatment with a LIFR antagonist. Together, these data provide support to the notion that development of LIF/LIFR inhibitors might have a role in the treatment of GC.

cancer biology↗

bioRxiv2021

Analysis of gastric cancer transcriptome allows the identification of histotype specific molecular signatures with prognostic potential

Gastric cancer is the fifth most common malignancy but the third leading cause of cancer-associated mortality worldwide. Therapy for gastric cancer remain largely suboptimal making the identification of novel therapeutic targets an urgent medical need. In the present study we have carried out a high-throughput sequencing of transcriptome expression in patients with gastric cancers. Twenty-four patients, among a series of 53, who underwent an attempt of curative surgery for gastric cancers in a single center, were enrolled. Patients were sub-grouped according to their histopathology into diffuse and intestinal types, and the transcriptome of the two subgroups assessed by RNAseq analysis and compared to the normal gastric mucosa. The results of this investigation demonstrated that the two histopathology phenotypes express two different patterns of gene expression. A total of 2064 transcripts were differentially expressed between neoplastic and non neoplastic tissues: 772 were specific for the intestinal type and 407 for the diffuse type. Only 885 transcripts were simultaneously differentially expressed by both tumors. The per pathway analysis demonstrated an enrichment of extracellular matrix and immune dysfunction in the intestinal type including CXCR2, CXCR1, FPR2, CARD14, EFNA2, AQ9, TRIP13, KLK11 and GHRL. At the univariate analysis reduced levels AQP9 was found to be a negative predictor of 4 years survival. In the diffuse type low levels CXCR2 and high levels of CARD14 mRNA were negative predictors of 4 years survival. In summary, we have identified a group of genes differentially regulated in the intestinal and diffuse histo-types of gastric cancers with AQP9, CARD14 and CXCR2 impacting on patients prognosis, although CXCR2 is the only factor independently impacting overall survival. Simple summaryGastric cancer is the fifth most common malignancy and the third leading cause of cancer-associated mortality worldwide. Although several new pharmacological approaches are currently developed, surgery remains the unique valid option of treatment but survival remains very poor over the last decades. Therefore, understanding the underlying molecular mechanisms of the gastric carcinogenesis and identifying sensitive biomarkers could be helpful for the prevention and treatment of the disease. Currently, the high-throughput sequencing techniques, in particular the transcriptomic analysis (RNA-seq) represents a validated technique to obtain a molecular characterization of human cancers. Moreover, it has been established that genetic susceptibility and environmental factors, such as microbial infections may contribute to carcinogenesis. We have characterized the different patterns of gene expression, using RNA-seq analysis and correlated these findings with gastric cancer histological subtypes.

cancer biology↗

bioRxiv2019

Active transport of brilliant blue FCF across the Drosophila midgut and Malpighian tubule epithelia

Under conditions of stress, many animals suffer from epithelial barrier disruption that can cause molecules to leak down their concentration gradients, potentially causing a loss of organismal homeostasis, further injury or death. Drosophila is a common insect model, used to study barrier disruption related to aging, traumatic injury, or environmental stress. Net leak of a non-toxic dye (Brilliant blue FCF) from the gut lumen to the hemolymph is often used to identify barrier failure under these conditions, but Drosophila are capable of actively transporting structurally-similar compounds. Here, we examined whether cold stress (like other stresses) causes Brilliant blue FCF (BB-FCF) to appear in the hemolymph of flies fed the dye, and if so whether Drosophila are capable of clearing this dye from their body following chilling. Using in situ midgut leak and transport assays as well as Ramsay assays of Malpighian tubule transport, we tested whether these ionoregulatory epithelia can actively transport BB-FCF. In doing so, we found that the Drosophila midgut and Malpighian tubules can mobilize BB-FCF via an active transcellular pathway, suggesting that elevated concentrations of the dye in the hemolymph may occur from increased paracellular permeability, reduced transcellular clearance, or both.\n\nSummary StatementDrosophila are able to actively secrete Brilliant blue FCF, a commonly used marker of barrier dysfunction

physiology↗

bioRxiv2019

An impressive capacity for cold tolerance plasticity protects against ionoregulatory collapse in the disease vector, Aedes aegypti

O_LIThe mosquito Aedes aegypti is largely confined to tropical and subtropical regions but its range has recently been spreading to colder climates. As insect biogeography is closely tied to environmental temperature, understanding the limits of Ae. aegypti thermal tolerance and their capacity for phenotypic plasticity is important in predicting the spread of this species.\nC_LIO_LIIn this study we report on the chill coma onset and recovery, as well as low temperature survival phenotypes of larvae and adults of Aedes aegypti that developed or were acclimated to 15{degrees}C (cold) or 25{degrees}C (warm).\nC_LIO_LIDevelopmental cold acclimation did not affect chill coma onset of larvae but substantially reduced chill coma onset temperatures in adults. Chill coma recovery time was affected by both temperature and the duration of exposure, and developmental and adult acclimation both strongly mitigated these effects and increased rates of survival following prolonged chilling.\nC_LIO_LIFemale adults were far less likely to take a blood meal when cold acclimated and simply exposing females to blood (without feeding) attenuated some of the beneficial effects of cold acclimation on chill coma recovery time.\nC_LIO_LILastly, larvae suffered from hemolymph hyperkalemia when chilled, but development in the cold attenuated the imbalance, which suggests that acclimation can prevent cold-induced ionoregulatory collapse in this species.\nC_LIO_LIOur results demonstrate that Aedes aegypti larvae and adults have the capacity to acclimate to cold temperatures and do so at least in part by better maintaining ion balance in the cold. This ability for cold acclimation may facilitate the spread of this species to higher latitudes, particularly in an era of climate change.\nC_LI

physiology↗

bioRxiv2018

Anti-diuretic activity of a CAPA neuropeptide can compromise Drosophila chill tolerance

For insects, chilling injuries that occur in the absence of freezing are often related to a systemic loss of ion and water balance that leads to extracellular hyperkalemia, cell depolarization, and the triggering of apoptotic signalling cascades. The ability of insect ionoregulatory organs (e.g. the Malpighian tubules) to maintain ion balance in the cold has been linked to improved chill tolerance, and many neuroendocrine factors are known to influence ion transport rates of these organs. Injection of micromolar doses of CAPA (an insect neuropeptide) have been previously demonstrated to improve Drosophila cold tolerance, but the mechanisms through which it impacts chill tolerance are unclear, and low doses of CAPA have been demonstrated to cause anti-diuresis in other insects, including dipterans. Here, we provide evidence that low (fM) and high ({micro}M) doses of CAPA impair and improve chill tolerance, respectively, via two different effects on Malpighian tubule ion and water transport. While low doses of CAPA are anti-diuretic, reduce tubule K+ clearance rates and reduce chill tolerance, high doses facilitate K+ clearance from the haemolymph and increase chill tolerance. By quantifying CAPA peptide levels in the central nervous system, we estimated the maximum achievable hormonal titres of CAPA, and found evidence to suggest that CAPA may function as an anti-diuretic peptide in Drosophila. We provide the first evidence of a neuropeptide that can negatively affect cold tolerance in an insect, and the first evidence of CAPA as an anti-diuretic peptide in this ubiquitous insect model.\n\nSummary StatementMany insects ion balance in the cold. We show how one neuropeptide can slow ion transport and reduce the cold tolerance of a fly.

physiology↗

bioRxiv2017

Functional Plasticity of the gut and the Malpighian tubules underlies cold acclimation and mitigates cold-induced hyperkalemia in Drosophila melanogaster

At low temperatures, Drosophila, like most insects, lose the ability to regulate ion and water balance across the gut epithelia, which can lead to a lethal increase of [K+] in the hemolymph (hyperkalemia). Cold-acclimation, the physiological response to low temperature exposure, can mitigate or entirely prevent these ion imbalances, but the physiological mechanisms that facilitate this process are not well understood. Here, we test whether plasticity in the ionoregulatory physiology of the gut and Malpighian tubules of Drosophila may aid in preserving ion homeostasis in the cold. Upon adult emergence, D. melanogaster females were subjected to seven days at warm (25{degrees}C) or cold (10{degrees}C) acclimation conditions. The cold acclimated flies had a lower critical thermal minimum (CTmin), recovered from chill coma more quickly, and better maintained hemolymph K+ balance in the cold. The improvements in chill tolerance coincided with increased Malpighian tubule fluid secretion and better maintenance of K+ secretion rates in the cold, as well as reduced rectal K+ reabsorption in cold-acclimated flies. To test whether modulation of ion-motive ATPases, the main drivers of epithelial transport in the alimentary canal, mediate these changes, we measured the activities of Na+-K+-ATPase and V-type H+-ATPase at the Malpighian tubules, midgut, and hindgut. Na+/K+-ATPase and V-type H+-ATPase activities were lower in the midgut and the Malpighian tubules of cold-acclimated flies, but unchanged in the hindgut of cold acclimated flies, and were not predictive of the observed alterations in K+ transport. Our results suggest that modification of Malpighian tubule and gut ion and water transport likely prevents cold-induced hyperkalemia in cold-acclimated flies and that this process is not directly related to the activities of the main drivers of ion transport in these organs, Na+/K+- and V-type H+-ATPases.\n\nSummary StatementAt low temperatures, insects lose the ability to regulate ion and water balance and can experience a lethal increase in hemolymph [K+]. Previous exposure to low temperatures can mitigate this effect and improve chill tolerance. Here, we show that plasticity of ion and fluid transport across the Malpighian tubule and rectal epithelia likely drive this response.

zoology↗

bioRxiv2017

Thermal Acclimation Mitigates Cold-Induced Paracellular Leak From The Drosophila Gut

When chilled to temperatures below their critical thermal minimum, chill susceptible insects can suffer tissue damage and die. The mechanisms that cause this chilling injury are not well understood but a growing body of evidence suggests that a loss of ion and water homeostasis in the cold leads to hemolymph hyperkalemia that depolarizes cells, leading to cell death. The apparent root of this cascade of issues is the net leak of osmolytes down their concentration gradients in the cold. Many insects, however, are capable of adjusting their thermal physiology, and cold-acclimated Drosophila can maintain homeostasis and avoid chilling injury better than warm-acclimated flies. Here, we test whether the cold-induced loss of osmotic homeostasis is associated with a loss of epithelial barrier function in Drosophila, and provide the first evidence of cold-induced epithelial barrier failure in an invertebrate. Flies exposed to 0{degrees} C had increased rates of paracellular leak through the gut epithelia, but cold acclimation reduced paracellular permeability, both before and during cold stress, and improved cold tolerance. This adjustment in barrier function was associated with changes in the abundance of select septate junction proteins and the appearance of a tortuous ultrastructure in subapical intercellular regions of contact between adjacent midgut epithelial cells. Thus, cold causes paracellular leak in a chill susceptible insect and cold acclimation can mitigate this effect, at least partly through changes in the composition and structure of transepithelial barriers.\n\nSummary StatementChilling disrupts barrier function of the gut of flies and cold acclimation can mitigate this problem through changes in paracellular occluding junctions.

physiology↗