Biology subjects

Dalle Carbonare, L.

Publications and source records attributed to Dalle Carbonare, L..

7 recordsLinked to original sources

bioRxiv2025

Progressive oxygenation of developing leaves directs morphogenesis

Oxygen availability underpins energy production in multicellular organisms, yet internal oxygen gradients arise in both plants and animals. Plants sense these variations via the PLANT CYSTEINE OXIDASE branch of the N-degron pathway, which regulates the stability of key transcription factors. Originally linked to metabolic control, this pathway recently emerged as a development regulator. While the shoot apical meristem was shown to be hypoxic, the oxygen dynamics of organs originating from this low-oxygen niche remain unknown. Here we show that developing leaves form a spatiotemporal oxygen gradient that is sensed through the oxygen sensing machinery. This pathway integrates local oxygen availability to regulate leaf morphogenesis: early hypoxia restricts cell expansion, while subsequent distal-to-proximal oxygenation enables specialized cell fates acquisition. Our findings reveal that oxygen acts as a positional cue in normal growth, guiding developmental trajectories. Our work highlights opportunities to harness oxygen gradients or sensing to direct plant form and function.

plant biology↗

bioRxiv2024

Engineering prolyl hydroxylase-dependent proteolysis enables the orthogonal control of hypoxia responses in plants

Vascular plants and metazoans use selective proteolysis of transcription factors to control the adaptive responses to hypoxia, although through distinct biochemical mechanisms. The reason for this divergence is puzzling, especially when considering that the molecular components necessary to establish both strategies are conserved across the two kingdoms. To explore an alternative evolutionary scenario where plants sense hypoxia as animals do, we engineered a three-components system aimed to target proteins for degradation in an oxygen dependent manner in Arabidopsis thaliana. Applying the synthetic biology framework, we produced a hypoxia-responsive switch independent of endogenous pathways. When applied to control transcription, the synthetic system partially restored hypoxia responsiveness in oxygen-insensitive mutants. Additionally, we demonstrated its potential to regulate growth under flood-induced hypoxia. Our work highlights the use of synthetic biology to reprogram signalling pathways in plants, providing insights into the evolution of oxygen sensing and ofering tools for crop improvement under stress conditions.

synthetic biology↗

bioRxiv2024

H2O2 repurposes the plant oxygen-sensing machinery to control the transcriptional response to oxidative stress

Plants sense reduced oxygen availability (hypoxia) through Plant Cysteine Oxidases (PCOs). Reduced PCO activity in hypoxia, as seen during submergence, stabilises Group VII Ethylene Response Factors (ERFVIIs), master regulators of adaptive metabolic and anatomic responses. Equally important is timely arrest of these responses upon reoxygenation, assumed to occur through ERFVII degradation. Reoxygenation involves reactive oxygen species (ROS) production. Here, we report that instead of degradation, reoxygenation results in ERFVII nuclear stabilisation, an effect mimicked by direct H2O2 treatment. Interestingly, typical hypoxia marker genes are repressed while genes involved in ROS homeostasis and oxidative stress protection are upregulated. Using in planta, heterologous and biochemical assays, we reveal that ROS-related ERFVII stabilisation is caused by PCO inactivation. Stabilised ERFVIIs are retained at hypoxia-responsive promoters but become repressors. Our findings suggest that by responding to both oxygen and ROS, PCOs coordinate ERFVII stability to regulate timely responses to damaging fluctuations in oxygen availability.

plant biology↗

bioRxiv2024

The role of ERFVIIs as oxygen-sensing transducers in the evolution of land plant response to hypoxia

The transcriptional response to low oxygen (hypoxia) in the flowering plant Arabidopsis thaliana is transduced through group VII Ethylene Response Factor (ERFVII) transcription factors, whose proteolysis is oxygen-dependent via the PLANT CYSTEINE OXIDASE (PCO) N-degron pathway. When and how this response to hypoxia evolved in land plants remains unknown. Here we investigated the conservation and divergence of transcriptional responses to hypoxia in major land plant clades. We identified induction of gene functions associated with glycolysis and fermentation as part of a conserved response across all land plant divisions. Our results indicate that ERFVIIs appeared in the last common ancestor of vascular plants with true roots, concurrently with oxygen-dependent destabilisation, to regulate hypoxia-adaptive genes. Proteins from other ERF groups have been recruited multiple times in different clades as substrates of the PCO N-degron pathway. Our results demonstrate that the response of land plants to hypoxia has been refined in derived clades through the evolution of ERFVIIs as transcriptional transducers, that occurred concomitantly with the appearance of vascular systems and roots as foraging systems through hypoxic soil.

plant biology↗

bioRxiv2021

Immunogenicity and pre-clinical efficacy of an OMV-based SARS-CoV-2 vaccine

The vaccination campaign against SARS-CoV-2 relies on the world-wide availability of effective vaccines, with a potential need of 20 billion vaccine doses to fully vaccinate the world population. To reach this goal, the manufacturing and logistic processes should be affordable to all countries, irrespectively of economical and climatic conditions. Outer membrane vesicles (OMVs) are bacterial-derived vesicles that can be engineered to incorporate heterologous antigens. Given the inherent adjuvanticity, such modified OMVs can be used as vaccine to induce potent immune responses against the associated protein. Here we show that OMVs engineered to incorporate peptides derived from the receptor binding motif (RBM) of the spike protein from SARS-CoV-2 elicit an effective immune response in immunized mice, resulting in the production of neutralizing antibodies. The immunity induced by the vaccine is sufficient to protect K18-hACE2 transgenic mice from intranasal challenge with SARS-CoV-2, preventing both virus replication in the lungs and the pathology associated with virus infection. Furthermore, we show that OMVs can be effectively decorated with RBM peptides derived from a different genetic variant of SARS-CoV-2, inducing a similarly potent neutralization activity in vaccinated mice. Altogether, given the convenience associated with ease of engineering, production and distribution, our results demonstrate that OMV-based SARS-CoV-2 vaccines can be a crucial addition to the vaccines currently available.

immunology↗

bioRxiv2020

Acquisition of hypoxia inducibility by oxygen sensing N-terminal cysteine oxidase in spermatophytes

N-terminal cysteine oxidases (NCOs) are enzymes that use molecular oxygen to oxidize the amino-terminal cysteine of specific proteins, thereby initiating the proteolytic N-degron pathway and thus conferring them oxygen-dependent instability. To expand the characterization of the plant family of NCOs (PCOs), we performed a phylogenetic analysis across different plant taxa in terms of sequence similarity and transcriptional regulation. Based on this survey, we propose a distinction of PCOs into two main groups: A-type and B-type sequences. A-type PCOs are conserved across all plant species and are generally unaffected at the mRNA level by oxygen availability. Instead, B-type PCOs differentiated in spermatophytes to acquire specific amino acid features and transcriptional regulation in response to hypoxia. Both groups of PCO proteins possess the ability to destabilize Cys-initiating proteins. Indeed, the inactivation of two A-type PCOs in Arabidopsis thaliana, PCO4 and PCO5, is sufficient to activate, at least partially, the anaerobic response in young seedlings, whereas the additional removal of B-type PCOs leads to a stronger induction of anaerobic genes and impairs plant growth and development. Our results show that both PCO types are required to regulate the anaerobic response in angiosperm. Therefore, while it is possible to distinguish two clades within the PCO family, separated by both amino acid features and transcriptional regulation, we conclude that they both contribute to restrain the anaerobic transcriptional program in normoxic conditions and together generate a molecular switch to toggle the hypoxic response in Arabidopsis.One sentence summary Hypoxic induction of Plant Cysteine Oxidases has been acquired and fixed in seed plants by ancestor proteins able to initiate the proteolysis of Cys-initiating protein substrates by the Arg/N-degron pathway.View Full Text

plant biology↗

bioRxiv2020

Effects of C-peptide replacement therapy on bone microarchitecture parameters in streptozotocin-diabetic rats.

Pathological pathways involved in the development of diabetic complications are still unclear. Several studies suggested a pathogenic role of C-peptide deficiency in vascular and neuropathic complications. However, to date, the role of C-peptide on diabetes-related bone loss has not been investigated. The objective of this study was to test the effects of a 6-week regimen of rat C-peptide infusion on bone by combining micro-CT imaging with histological testing. Twenty-three, four-month-old male Wistar rats were randomly divided into three groups: Normal control group; Sham diabetic control group; Diabetic plus C-peptide group. Diabetes was induced by injection of streptozotocin. Rat C-peptide was delivered via subcutaneously osmopumps. We assessed several trabecular microarchitectural parameters and cellular and matrix proteins in bone tissue sections. At the end of the study, both the normal control and diabetic plus C-peptide groups had a higher tibia weight than the diabetic control group (p = 0.05 and p = 0.02, respectively). C-peptide levels significantly and positively correlated with the trabecular thickness (r= 0.45, p=0.08) and negatively with structure model index (r= -0.40, p=0.09). Furthermore, it positively correlated with one of the histological assessments (i.e. PLIN1 score; p=0.02). Micro-CT evaluation showed significant inter-group differences in trabecular thickness (p=0.02), trabecular space (p = 0.05) and cross-sectional thickness (p=0.05). Diabetic plus C-peptide group showed a higher trabecular thickness (p<0.001), cross-sectional thickness (p=0.03) and a lower trabecular space (p=0.05) than the normal control group. Both the normal control and diabetic plus C-peptide groups had more Runx-2 and PLIN1 positive cells in comparison to the diabetic control group (p = 0.045 and p = 0.034). For the first time we demonstrated that the diabetic rats receiving rat C-peptide had higher quality of trabecular bone, than diabetic rats not receiving it. C-peptide could have a role in the prevention of diabetes-related bone loss.

systems biology↗