Evaluation of human skin response to solar-simulated radiation in an ex vivo model: Effects and photoprotection of L-Carnosine.

Sunlight, and more specifically the UV component, induces several skin damages, including sunburns, erythema and photoaging. The purpose of this work is to set up an ex vivo human skin model to assess the capacity of active principles in protecting skin from the deleterious effects of solar radiation. Ex vivo human skin biopsies were cultured in an air-liquid interface and exposed to solar-simulated radiation (SSR, 300-750 nm). L-Carnosine (0.2% and 2%) was applied topically to be tested as photoprotective compound. The effect on oxidative stress induction, photoaging and skin transcriptional profile was assessed by evaluating reactive oxygen species, advanced glycosylation end products formation and gene expression changes. In our model, SSR increases ROS production and AGE accumulation and affects the expression of genes related to oxidative stress, pigmentation, immunity, inflammation and photoaging. Among these pathways, 11 genes were selected as biomarkers to evaluate the skin solar radiation response. Results showed that L-Carnosine provides effective prevention against solar radiation damages reducing ROS, AGEs and mitigating the modulation of the selected biomarker genes. In conclusion, we report that our ex vivo skin model is a valuable system to assess the consequences of solar light exposure and the capacity of topically applied L-Carnosine to counteract them.

Early prolonged prone position in noninvasively ventilated patients with SARS-CoV-2-related moderate-to-severe hypoxemic respiratory failure: clinical outcomes and mechanisms for treatment response in the PRO-NIV study.

BACKGROUND: Whether prone position (PP) improves clinical outcomes in COVID-19 pneumonia treated with noninvasive ventilation (NIV) is unknown. We evaluated the effect of early PP on 28-day NIV failure, intubation and death in noninvasively ventilated patients with moderate-to-severe acute hypoxemic respiratory failure due to COVID-19 pneumonia and explored physiological mechanisms underlying treatment response. METHODS: In this controlled non-randomized trial, 81 consecutive prospectively enrolled patients with COVID-19 pneumonia and moderate-to-severe (paO2/FiO2 ratio < 200) acute hypoxemic respiratory failure treated with early PP + NIV during Dec 2020-May 2021were compared with 162 consecutive patients with COVID-19 pneumonia matched for age, mortality risk, severity of illness and paO2/FiO2 ratio at admission, treated with conventional (supine) NIV during Apr 2020-Dec 2020 at HUMANITAS Gradenigo Subintensive Care Unit, after propensity score adjustment for multiple baseline and treatment-related variables to limit confounding. Lung ultrasonography (LUS) was performed at baseline and at day 5. Ventilatory parameters, physiological dead space indices (DSIs) and circulating inflammatory and procoagulative biomarkers were monitored during the initial 7 days. RESULTS: In the intention-to-treat analysis. NIV failure occurred in 14 (17%) of PP patients versus 70 (43%) of controls [HR = 0.32, 95% CI 0.21-0.50; p < 0.0001]; intubation in 8 (11%) of PP patients versus 44 (30%) of controls [HR = 0.31, 95% CI 0.18-0.55; p = 0.0012], death in 10 (12%) of PP patients versus 59 (36%) of controls [HR = 0.27, 95% CI 0.17-0.44; p < 0.0001]. The effect remained significant within different categories of severity of hypoxemia (paO2/FiO2 < 100 or paO2/FiO2 100-199 at admission). Adverse events were rare and evenly distributed. Compared with controls, PP therapy was associated with improved oxygenation and DSIs, reduced global LUS severity indices largely through enhanced reaeration of dorso-lateral lung regions, and an earlier decline in inflammatory markers and D-dimer. In multivariate analysis, day 1 CO2 response outperformed O2 response as a predictor of LUS changes, NIV failure, intubation and death. CONCLUSION: Early prolonged PP is safe and is associated with lower NIV failure, intubation and death rates in noninvasively ventilated patients with COVID-19-related moderate-to-severe hypoxemic respiratory failure. Early dead space reduction and reaeration of dorso-lateral lung regions predicted clinical outcomes in our study population. CLINICAL TRIAL REGISTRATION: ISRCTN23016116 . Retrospectively registered on May 1, 2021.

Characterization of Ambra1 in asexual cycle of a non-vertebrate chordate, the colonial tunicate Botryllus schlosseri, and phylogenetic analysis of the protein group in Bilateria.

Ambra1 is a positive regulator of autophagy, a lysosome-mediated degradative process involved both in physiological and pathological conditions. Nowadays, Ambra1 has been characterized only in mammals and zebrafish. Through bioinformatics searches and targeted cloning, we report the identification of the complete Ambra1 transcript in a non-vertebrate chordate, the tunicate Botryllus schlosseri. Tunicata is the sister group of Vertebrata and the only chordate group possessing species that reproduce also by blastogenesis (asexual reproduction). B. schlosseri Ambra1 deduced amino acid sequence is shorter than vertebrate homologues but still contains the typical WD40 domain. qPCR analyses revealed that the level of B. schlosseri Ambra1 transcription is temporally regulated along the colonial blastogenetic cycle. By means of similarity searches we identified Wdr5 and Katnb1 as proteins evolutionarily associated to Ambra1. Phylogenetic analyses on Bilateria indicate that: (i) Wdr5 is the most related to Ambra1, so that they may derive from an ancestral gene, (ii) Ambra1 forms a group of ancient genes evolved before the radiation of the taxon, (iii) these orthologous Ambra1 share the two conserved WD40/YVTN repeat-like-containing domains, and (iv) they are characterized by ancient duplications of WD40 repeats within the N-terminal domain.

Beneficial bacteria affect Danio rerio development by the modulation of maternal factors involved in autophagic, apoptotic and dorsalizing processes.

BACKGROUND/AIMS: Probiotic strains have been recognized to exert important roles in many biological systems, including immune response, growth, development and reproduction. However, to date, no studies have focused either on the relation among probiotics and maternal factors or on probiotics' ability to qualitatively and/or quantitatively modulate maternal transcripts. METHODS: In this study, the effects of Lactobacillus rhamnosus administered to parental fish on the control of maternal factors involved in autophagic, apoptotic and dorsalizing processes during zebrafish embryo development were assessed through q-PCRs, WMISH and TUNEL assay. RESULTS: The results we obtained show that probiotic induced significant changes in both maternal and zygotic mRNA levels involved in embryo development. The maternal autophagy-regulating genes herein investigated--ambra1a, ambra1b, beclin, lc3-, as well as those involved in the apoptotic process--caspase3, bcl2, bax--were modulated in disfavor and favor of the treated group, respectively. Also, the key transcripts ruling the dorsalizing process--goosecoid and chordin--were subject to a significant regulation of their gene expression. CONCLUSION: The results we acquired demonstrated that parentally administered Lactobacillus rhamnosus is able to modulate important physiological processes involved in zebrafish embryo development.

A developmental hepatotoxicity study of dietary bisphenol A in Sparus aurata juveniles.

Previous studies in rats have indicated that a diet enriched with Bisphenol A adversely effects metabolism and reproductive success. In rats exposed to BPA by maternal gavage, alteration in the developmental programming, higher obesity rates and reproductive anomalies were induced. Starting with this evidence, the aim of this study was to provide important insights on the effects induced by a BPA enriched diet, on the reproductive physiology and metabolism of juvenile fish, simulating the scenario occurring when wild fish fed on prey contaminated with environmental BPA. Seabream was chosen as model, as it is one of the primary commercial species valued by consumers and these results could provide important findings on adverse effects that could be passed on to humans by eating contaminated fish. A novel method for measuring BPA in the food and water by affinity chromatography was developed. Analysis of signals involved in reproduction uncovered altered levels of vtg and Zp, clearly indicating the estrogenic effect of BPA. Similarly, BPA up-regulated catd and era gene expression. A noteworthy outcome from this study was the full length cloning of two vtg encoding proteins, namely vtgA and vtgB, which are differently modulated by BPA. Cyp1a1 and EROD activity were significantly downregulated, confirming the ability of estrogenic compounds to inhibit the detoxification process. GST activity was unaffected by BPA contamination, while CAT activity was down regulated. These results collectively confirm the estrogenic effect of BPA and provide additional characterization of novel vtg genes in Sparus aurata.

Zebrafish ambra1a and ambra1b knockdown impairs skeletal muscle development.

The essential role of autophagy in muscle homeostasis has been clearly demonstrated by phenotype analysis of mice with muscle-specific inactivation of genes encoding autophagy-related proteins. Ambra1 is a key component of the Beclin 1 complex and, in zebrafish, it is encoded by two paralogous genes, ambra1a and ambra1b, both required for normal embryogenesis and larval development. In this study we focused on the function of Ambra1, a positive regulator of the autophagic process, during skeletal muscle development by means of morpholino (MO)-mediated knockdown and compared the phenotype of zebrafish Ambra1-depleted embryos with that of Ambra1gt/gt mouse embryos. Morphological analysis of zebrafish morphant embryos revealed that silencing of ambra1 impairs locomotor activity and muscle development, as well as myoD1 expression. Skeletal muscles in ATG-morphant embryos displayed severe histopathological changes and contained only small areas of organized myofibrils that were widely dispersed throughout the cell. Double knockdown of ambra1a and ambra1b resulted in a more severe phenotype whereas defects were much less evident in splice-morphants. The morphants phenotypes were effectively rescued by co-injection with human AMBRA1 mRNA. Together, these results indicate that ambra1a and ambra1b are required for the correct development and morphogenesis of skeletal muscle.

A living biosensor model to dynamically trace glucocorticoid transcriptional activity during development and adult life in zebrafish.

Glucocorticoids (GCs) modulate many cellular processes through the binding of the glucocorticoid receptor (GR) to specific responsive elements located upstream of the transcription starting site or within an intron of GC target genes. Here we describe a transgenic fish line harboring a construct with nine GC-responsive elements (GREs) upstream of a reporter (EGFP) coding sequence. Transgenic fish exhibit strong fluorescence in many known GC-responsive organs. Moreover, its enhanced sensitivity allowed the discovery of novel GC-responsive tissue compartments, such as fin, eyes, and otic vesicles. Long-term persistence of transgene expression is seen during adult stages in several organs. Pharmacological and genetic analysis demonstrates that the transgenic line is highly responsive to drug administration and molecular manipulation. Moreover, reporter expression is sensitively and dynamically modulated by the photoperiod, thus proving that these fish are an in vivo valuable platform to explore GC responsiveness to both endogenous and exogenous stimuli.

Development and specification of cerebellar stem and progenitor cells in zebrafish: from embryo to adult.

BACKGROUND: Teleost fish display widespread post-embryonic neurogenesis originating from many different proliferative niches that are distributed along the brain axis. During the development of the central nervous system (CNS) different cell types are produced in a strict temporal order from increasingly committed progenitors. However, it is not known whether diverse neural stem and progenitor cell types with restricted potential or stem cells with broad potential are maintained in the teleost fish brain. RESULTS: To study the diversity and output of neural stem and progenitor cell populations in the zebrafish brain the cerebellum was used as a model brain region, because of its well-known architecture and development. Transgenic zebrafish lines, in vivo imaging and molecular markers were used to follow and quantify how the proliferative activity and output of cerebellar progenitor populations progress. This analysis revealed that the proliferative activity and progenitor marker expression declines in juvenile zebrafish before they reach sexual maturity. Furthermore, this correlated with the diminished repertoire of cell types produced in the adult. The stem and progenitor cells derived from the upper rhombic lip were maintained into adulthood and they actively produced granule cells. Ventricular zone derived progenitor cells were largely quiescent in the adult cerebellum and produced a very limited number of glia and inhibitory inter-neurons. No Purkinje or Eurydendroid cells were produced in fish older than 3 months. This suggests that cerebellar cell types are produced in a strict temporal order from distinct pools of increasingly committed stem and progenitor cells. CONCLUSIONS: Our results in the zebrafish cerebellum show that neural stem and progenitor cell types are specified and they produce distinct cell lineages and sub-types of brain cells. We propose that only specific subtypes of brain cells are continuously produced throughout life in the teleost fish brain. This implies that the post-embryonic neurogenesis in fish is linked to the production of particular neurons involved in specific brain functions, rather than to general, indeterminate growth of the CNS and all of its cell types.

Ambra1 knockdown in zebrafish leads to incomplete development due to severe defects in organogenesis.

AMBRA1 is a positive regulator of the BECN1-dependent program of autophagy recently identified in mouse. In this study, we cloned the full-length cDNAs of ambra1a and ambra1b zebrafish paralogous genes. As in mouse, both Ambra1 proteins contain the characteristic WD40 repeat region. The transcripts of both genes are present as maternal RNAs in the eggs and display a gradual decline until 8 hpf, being replaced by zygotic mRNAs from 12 hpf onwards. After 24 hpf, the transcripts are mainly localized in the head, suggesting a possible role in brain development. To check their developmental roles, we adopted morpholino knockdown to block either translation (ATGMOs) or splicing (SPLICMOs). Treatment with ATGMOs causes severe embryonic malformations, as prelarvae could survive for only 3 and 4 days in ambra1a and b morphants, respectively. Treatment with SPLICMOs led to developmental defects only at a late stage, indicating the importance of maternally supplied ambra1 transcripts. Analysis of the levels of Lc3-II, an autophagosome-specific marker, in the presence of lysosome inhibitors evidenced a reduction in the rate of autophagosome formation in both MOs-injected embryos at 48 hpf, more pronounced in the case of ambra1a gene. Although some defects, such as body growth delay, curved shape and hemorrhagic pericardial cavity were present in both morphants, the occurrence of specific phenotypes, such as major abnormalities of brain development in ambra1a morphants, suggests the possible acquisition of specific functions by the two paralogous genes that are both required during development and do not compensate each other following knockdown.

Interplay between autophagy and apoptosis in the development of Danio rerio follicles and the effects of a probiotic.

The present study investigated autophagic processes in Danio rerio preovulatory follicles (Stage III and IV). There were more autophagosomes, as revealed by electron microscopy, in follicles from females fed the probiotic Lactobacillus rhamnosus IMC 501. This was confirmed by increased expression of genes involved in the autophagic process, namely ambra1, becn1, lc3 and uvrag. In addition, preovulatory follicles from females fed the probiotic contained more microtubule-associated protein 1 light chain 3 isoform II (LC3-II) and less p62 protein. The increased autophagy in preovulatory follicles from females fed the probiotic was concomitant with a decrease in the apoptotic process in the ovary, as evidenced by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling analysis and confirmed by lower expression of genes involved in apoptosis (i.e., p53, bax, apaf and cas3) and higher expression as igfII and igf1r. The results of the present study provide preliminary evidence of the involvement of autophagy during follicle development in the zebrafish ovary. In addition, we have demonstrated for the first time that a functional food, such as L. rhamnosus IMC 501, can modulate the balance between apoptosis and autophagy that regulates ovary physiology in zebrafish by inhibiting follicular apoptosis and improving follicular survival.

Disruptions of global and JAGGED1-mediated notch signaling affect thyroid morphogenesis in the zebrafish.

The mechanisms underlying the early steps of thyroid development are largely unknown. In search for novel candidate genes implicated in thyroid function, we performed a gene expression analysis on thyroid cells revealing that TSH regulates the expression of several elements of the Notch pathway, including the ligand Jagged1. Because the Notch pathway is involved in cell-fate determination of several foregut-derived endocrine tissues, we tested its contribution in thyroid development using the zebrafish, a teleost model recapitulating the mammalian molecular events during thyroid development. Perturbing the Notch signaling (e.g. mib mutants, γ-secretase inhibition, or Notch intracellular domain overexpression), we obtained evidence that this pathway has a biological role during the earlier phases of thyroid primordium induction, limiting the number of cells that proceed to a specialized fate and probably involving actions from surrounding tissues. Moreover, we were able to confirm the expression of Jagged1 during different phases of zebrafish thyroid development, as well as in mouse and human thyroid tissues. The two orthologues to the single jagged1 gene (JAG1) in humans, jag1a and jag1b, are expressed with different spatiotemporal patterns in the developing zebrafish thyroid. Both jag1a and jag1b morphants, as well as jag1b mutant fish line, display thyroid hypoplasia and impaired T(4) production; this thyroid phenotype was rescued by coinjection of human JAG1 mRNA. In conclusion, Notch pathway is involved in the early steps of thyroid morphogenesis, and Jagged1-Notch signal is required for zebrafish thyroid development and function. Thus, genetic alterations affecting the Notch pathway may confer susceptibility for thyroid dysgenesis.

Bioinformatic and molecular characterization of beta-defensins-like peptides isolated from the green lizard Anolis carolinensis.

The high resistance of lizards to infections indicates that anti-microbial peptides may be involved. Through the analysis of the green lizard (Anolis carolinensis) genome and the expressed sequence tag (EST) libraries 32 beta-defensin-like-peptides have been identified. The level of expression of some of these genes in different tissues has been determined by semi-quantitative RT-PCR. Gene expression and structure analysis suggest the presence of alternative splicing mechanisms, with a number of exons ranging from two to four, similar to that for beta-defensins genes in mammals. Lizard beta-defensin-like peptides present the characteristic cysteine-motif identified in mammalian and avian beta-defensins. Phylogenetic analysis indicates that some lizard beta-defensins-like peptides are related to crotamine and crotamin-like peptides of snakes and lizards suggesting that beta-defensins and venomous peptides have a common ancestor gene.

The knockdown of the maternal estrogen receptor 2a (esr2a) mRNA affects embryo transcript contents and larval development in zebrafish.

In zebrafish, ovulated oocytes are loaded with maternal estrogen receptor 2a (esr2a) mRNA which is spread as granular and filamentous structures throughout the central ooplasm and is promptly relocated inside the blastodisc area at the 1-cell stage (0.2h post-fertilization, hpf), as shown by in situ hybridization. This transcript is available for translation until its sharp decline from 4 to 8 hpf, being replaced by low levels of zygotic esr2a mRNA mainly localized in the head region and around the yolk sac from 24 hpf until hatching at 48 hpf. To test the functional role of the maternal esr2a mRNA, 1- or 2-cell embryos were injected with 10.3 ng each of morpholino (MO) to knockdown translation (MO2-esr2a) of both maternal and zygotic esr2a transcripts, with a missplicing MO (MO3-esr2a) to effectively block post-transcriptionally the zygotic transcript alone, and with a non-specific MO-control. Treatment with MO2-esr2a increased apoptosis in embryos, especially in the brain, and caused severe malformations in 63% of 1-5 dpf larvae, as compared to 10-11% in those treated with MO3-esr2a and MO-control. Defects included body growth delay with curved shape, persistent yolk sac with reduced sub-intestinal veins and swollen yolk extension, abnormal brain and splanchnocranium development, smaller eyes and otic vesicles, pericardial oedema, uninflated swim bladder and rudimentary caudal fin with aberrant circular swimming. Affected larvae could survive for only 12-14 days. The MO2-esr2a phenotype was rescued with co-injection of 30 pg/embryo of mutated zebrafish esr2a mRNA encoding the full length of Esr2a, but containing eight silent mutations in the region recognised by MO2-esr2a. A lower dosage (15 pg) failed to recover mortality and abnormality. Raising the dosage to 60 and 90 pg increased abnormality, but not mortality, whereas with 120 pg both mortality and abnormality worsened, indicating a strict quantitative requirement of Esr2a. Co-injection of an anti-p53 MO failed to rescue the MO2-esr2a phenotype, eliminating the possibility of off-target effects. Pangenomic microarray analysis revealed that 240 and 219 significantly expressed transcripts were up- and down-regulated, respectively, by maternal Esr2a protein deficiency in 8-hpf MO2-esr2a embryos. Also at 48 hpf, 162 and 120 presumably zygotic transcripts were up- and down-regulated, respectively, but only 18 were in common with each of the 8-hpf sets. In total, the transcripts from 705 genes were affected by Esr2a knockdown. These findings suggest the involvement of maternal esr2a mRNA, presumably transactivated by maternal 17ß-estradiol stored in the oocyte from enveloping granulosa cells, in the epigenetic programming of zebrafish development.

Deleterious mutations of a claw keratin in multiple taxa of reptiles.

We have recently shown that homologs of mammalian hair keratins are expressed in the claws of the green anole lizard, Anolis carolinensis. To test whether reptilian hair keratin homologs are functionally associated with claws, we investigated the conservation of the prototypical reptilian hair keratin homolog, hard acidic keratin 1 (HA1), in representative species from all main clades of reptiles. A complete cDNA of HA1 was cloned from the claw-forming epidermis of the lacertid lizard Podarcis sicula, and partial HA1 gene sequences could be amplified from genomic DNA of tuatara, lizards, gekkos, turtles, and crocodiles. In contrast, the HA1 gene of the limbless slow worm, Anguis fragilis, and of two species of turtles contained at least one deleterious mutation. Moreover, an HA1 gene was undetectable in the softshell turtle, snakes, and birds. Mapping the presence and absence of HA1 onto the phylogenetic tree of sauropsids suggested that the HA1 gene has been lost independently in several lineages of reptiles. The species distribution of HA1 is compatible with the hypothesis of a primary function of HA1 in claws but also shows that the formation of reptilian claws does not strictly depend on this keratin.

Differential expression and regulation of olig genes in zebrafish.

The members of the Olig gene family encode for basic helix-loop-helix (bHLH) transcription factors involved in neural cell type specification. Three Olig genes (Olig1, Olig2 and Olig3) have been identified in all known vertebrate models and a fourth one in anamniotes (olig4). Here we have performed a global analysis of olig genes during zebrafish embryonic development and determined which signaling pathways control their induction and regionalization in the CNS. Interestingly, zebrafish olig3 and olig4 together establish most of the expression domains corresponding to mouse Olig3. According to our data, olig1 is specifically confined to the oligodendrocyte lineage, whereas the other members display stratified expression in diencephalon, hindbrain, and spinal cord. We observed differential expression of olig genes within specific motoneuron and interneuron domains of the spinal cord. olig2, olig3, and olig4 expression appears to be regulated by nodal and FGF signaling during gastrulation and early somitogenesis, by RA signaling in the hindbrain, and by BMP and Hh signals along the dorsoventral axis of the embryonic CNS. Our findings suggest a role for olig genes in CNS patterning as well as in multiple cell fate decisions during neural differentiation.