Biology subjects

Bernardini, C.

Publications and source records attributed to Bernardini, C..

6 recordsLinked to original sources

bioRxiv2026

Microencapsulated Vaccinium floribundum Kunth extract promotes angiogenesis and attenuates inflammation in in vitro and in vivo models.

Natural products, especially polyphenol-rich medicinal plants, are increasingly investigated as multitarget therapeutics in both human and veterinary medicine for angiogenic regenerative properties and for inflammation based-diseases. Recent developments in natural product formulation, notably microencapsulation, have been shown to improve the stability, bioavailability, and controlled release of bioactive compounds. The integration of complementary in vitro and in vivo models is critical for evaluating both efficacy and translational potential. In this context, the present study assessed the phytochemical composition and biological activity of a microencapsulated Ecuadorian Vaccinium floribundum extract (VFM), using a combination of in vitro and in vivo approaches. VFM biochemical characterization identified 15 compounds, including flavonoids, procyanidins, dihydrochalcones, and phenolic acids, with chlorogenic acid and quercetin as the most abundant metabolites. Anthocyanins ideain and petunidin were also detected, confirming a rich bioactive profile. Primary porcine thoracic aortic endothelial cells (pAECs) were treated with VFM to assess cell viability and angiogenic potential and challenged with bacterial lipopolysaccharide (LPS) in the presence or absence of the extract. Anti-inflammatory effects were further evaluated in vivo using a carrageenan-induced mouse paw edema model. VFM enhanced endothelial cell viability, promoted capillary-like network and modulated early angiogenic signaling pathways. It mitigated LPS-induced endothelial dysfunction by reducing pro-inflammatory cytokines and oxidative stress markers. In vivo, paw edema assays confirmed its anti-inflammatory efficacy, with microencapsulation likely sustaining bioactive release. These findings support the traditional use of Vaccinium floribundum and highlight its potential for developing nutraceutical formulations targeting vascular and inflammatory disorders.

pharmacology and toxicology↗

bioRxiv2026

Arabidopsis Membrane Contact Site protein SYNAPTOTAGMIN A maintains sieve element endomembrane morphology and function

Very little is known about the sieve element (SE) endomembrane system. In terms of surface area, the most important membrane is the SE endoplasmic reticulum, characterized by a unique cisternal structure of anchored flat and smooth stacks. Plasma membrane contact sites (MCSs) play a crucial role in anchoring the endoplasmic reticulum (ER) to the plasma membrane (PM) and in maintaining membrane intergrity. Here, we tested their role of MCSs in the endomembrane system of the sieve elements. Synaptotagmin A (SYTA) is one of the best-studied proteins known to form ER-PM MCSs in plants. We show that SYTA:RFP co-localizes with SUC2::GFP and CALS7::GFP, confirming its presence in Arabidopsis SEs. In syta-1 mutants, SER lost its discrete shape and separated from the SE wall. The export of 14C-compounds from leaves of wild type plants was about 10% higher than in syta-1 mutants. Finally, we explored SYTAs role in phytoplasma infection response. After infection, syta-1 plants displayed 50% less callose deposition and an uneven distribution pattern of the pathogen. In conclusion, our work shows that SYTA is required for maintaining the unique shape of the SE endomembrane system, and for diverse SE functions including callose deposition, carbon translocation and response to pathogens.

plant biology↗

bioRxiv2025

Crosstalk between the Methyl-Cytosine Dioxygenase TET3 and the Methyl-CpG-binding protein MECP2 Controls Neuronal Maturation

Active DNA demethylation depends on Ten-Eleven-Translocation (TET) enzymes, which oxidize 5-methylcytosine (mC) to 5-hydroxymethylcytosine (hmC) and further derivatives. Mutations in TET3, encoding the predominant neuronal isoform, lead to Beck-Fahrner syndrome, a neurodevelopmental disorder. Using human iPSC-derived neurons, we show that TET3 is dispensable for neuronal specification but critical for subsequent maturation. Differentiating TET3-deficient neurons exhibit delayed transcriptional and proteomic transitions, altered synaptic signatures, and impaired network activity, indicating delayed functional maturation. Mechanistically, we identified an interaction between TET3 and the mC/hmC-binding protein MECP2, pathogenic variants of which cause Rett syndrome. MECP2 negatively regulates TET3 activity, as demonstrated in functional assays and by inverse hmC patterns in MECP2- and TET3-deficient neurons. Despite this, MECP2- and TET3-deficient neurons exhibit highly similar phenotypes later in differentiation. Our findings uncover a functional interplay between TET3 and MECP2 that coordinates DNA methylation and chromatin dynamics during neuronal maturation, suggesting a shared pathogenic mechanism in Beck-Fahrner and Rett syndromes.

neuroscience↗

bioRxiv2024

CRISPR gene and transcriptome engineering (CRISPRgate) improves loss-of-function genetic screening approaches

The CRISPR/Cas9 technology has revolutionized genotype-to-phenotype assignments through large-scale loss-of-function (LOF) screens. However, limitations like editing inefficiencies and unperturbed genes cause significant noise in data collection. To address this, we introduce CRISPR Gene and Transcriptome Engineering (CRISPRgate), which uses two specific sgRNAs to simultaneously repress and cleave the target gene within the same cell, increasing LOF efficiencies and reproducibility. CRISPRgate outperforms conventional CRISPRko, CRISPRi, or CRISPRoff systems in suppressing challenging targets and regulators of cell proliferation. Additionally, it efficiently suppresses modulators of EMT and impairs neuronal differentiation in a human iPSC model. In a multiplexed chromatin-focused phenotypic LOF screen, CRISPRgate exhibits improved depletion efficiency, reduced sgRNA performance variance, and accelerated gene depletion compared to individual CRISPRi or CRISPRko, ensuring consistency in phenotypic effects and identifying more significant gene hits. By combining CRISPRko and CRISPRi, CRISPRgate increases LOF rates without increasing genotoxic stress, facilitating library size reduction for advanced LOF screens. MotivationThe CRISPR technology (CRISPRko/CRISPRi) enables the specific depletion of target genes with fewer off-target effects, facilitating precise investigations of gene function. Despite its benefits, CRISPR applications have limitations. Residual active protein expression mediated by in-frame DNA repair or alternative splicing1-8 as well as strong epigenetic regulation and difficulties in sgRNA design to the transcription start site (TSS)9-12 hinder the full potential of loss-of-function studies using CRISPRko or CRISPRi. We aimed to achieve robust target gene reduction in order to improve the reproducibility of the CRISPR technology by integrating the widely used CRISPRko and CRISPRi approaches into a single application.

biochemistry↗

bioRxiv2022

Candidatus Liberibacter asiaticus reduces callose and reactive oxygen species production in the phloem

Huanglongbing (HLB) causes significant economic loss in citrus production worldwide. HLB is caused by Candidatus Liberibacter asiaticus (CLas), a gram-negative bacterium which inhabits the phloem exclusively. CLas infection results in accumulation of callose and reactive oxygen species in the phloem of infected plants, but little is known about the specific processes that take place during infection because of the sparse distribution of bacteria and the inaccessibility of the phloem inside the tree. In this study, we used the seed vasculatures, which accumulate a high number of CLas, as a model tissue to study CLas-host cellular interactions. In vasculature where CLas is abundant, sieve pore callose and H2O2 concentration were reduced compared to healthy seed vasculature. The expression of callose synthases (CalS) and respiratory burst oxidase homolog (RBOH) genes were downregulated in infected seeds compared to healthy ones. In leaves of HLB-infected plants, H2O2 concentration and CalS expression increased compared to uninfected leaves, but cells with CLas had lower levels of sieve plate callose compared to cells without CLas. Our results provide evidence that the bacteria manipulate cell metabolism to disable plant defenses and suggests that HLB disease is the result of a constant arms-race between the pathogen and a defense response, which is ultimately harmful to the host plant.

plant biology↗

bioRxiv2021

Knocking out AtCALS7 disturbs photoassimilate distribution and weakens defence against phytoplasma infection

Callose deposition around sieve pores, under control of callose synthase 7 (AtCALS7), has been interpreted as a mechanical response to limit pathogen spread in phytoplasma-infected plants. Wild-type and Atcals7ko mutants were therefore employed to unveil the mode of involvement of CALS7 in the plants response to phytoplasma infection. The fresh weights of healthy and CY-(Chrysanthemum Yellows) phytoplasma-infected Arabidopsis wild-type and mutant plants indicated two superimposed effects of the absence of CALS7: a partial impairment of photo-assimilate transport and a stimulated phytoplasma proliferation as illustrated by a significantly increased phytoplasma titre in Atcal7ko mutants. Further studies solely dealt with the effects of CALS7 absence on phytoplasma growth. Phytoplasma infection affected sieve-element substructure to a larger extent in mutants than in wild-type plants, which was also true for the levels of some free carbohydrates. Moreover, infection induced a similar upregulation of gene expression of enzymes involved in sucrose cleavage (AtSUS5, AtSUS6) and transmembrane transport (AtSWEET11) in mutants and wild-type plants, but an increased gene expression of carbohydrate transmembrane transporters (AtSWEET12, AtSTP13, AtSUC3) in infected mutants only. It remains still unclear how the absence of AtCALS7 leads to gene upregulation and how an increased intercellular mobility of carbohydrates and possibly effectors contributes to a higher susceptibility. It is also unclear if modified sieve-pore structures in mutants allow a better spread of phytoplasmas giving rise to higher titre. Author SummaryPhytoplasma infections are one of the most limiting factors for production of important crops all over the world. Phytoplasma disease epidemics can be handled mainly by insect-vector control using insecticides. Basic information about plant-phytoplasma interactions are still limited, nevertheless it is necessary to design new management and breeding strategies aimed to obtain more tolerant or resistant cultivars. Phytoplasmas are obligate intracellular parasites restricted to the phloem sieve tubes. Callose deposition at the sieve plates has been described since the 70s as a mechanical defence process to limit pathogen spread by occluding sieve pores. Studies reported 40 years later demonstrated that callose at the sieve pores is also involved in sieve-pore development and function and, hence, in mass-flow regulation, carbohydrate metabolism and distribution, and plant growth. Here, we reported on the role(s) of sieve-element callose in phytoplasma-infected Arabidopsis, using a mutant lacking AtCALS7, the enzyme responsible for callose synthesis in the sieve elements. The results indicate that loss of AtCAL7 appears to confer increased susceptibility to phytoplasma infection, due to alterations in expression of genes involved in sugar metabolism and membrane transport. In the long run, the identification of plant resistance or susceptibility traits against phytoplasmas will allow a complete re-organization of chemical control strategies, with obvious opportunities of reducing insecticide burden.

plant biology↗