Heterologous expression and biochemical characterization of innovative bacterial carbonic anhydrases involved in the carbon cycle and microbial virulence.

The conversion of carbon dioxide (CO2) to bicarbonate (HCO3-) and protons (H+) is a physiologically relevant reaction in all life kingdoms. The uncatalyzed hydration-dehydration reaction CO2 + H2O ⇋ HCO3- + H+ is slow at physiological pH and thus, in biological systems, the reaction is accelerated by enzymatic catalysts, called carbonic anhydrases (CAs, EC 4.2.1.1). CA isozymes have been found in virtually all mammalian tissues and cell types, where they function in CO2 transport and other physiological processes. Here, are described the biochemical characterization of thermostable and thermoactive CAs from extremophiles belonging to the genus Sulfurihydrogenibium. Moreover, it has been carried out a wide study concerning the inhibition profiles of CAs identified in the genome of pathogens causing disease in humans, such as Vibrio cholerae and Plasmodium falciparum. CAs identified in the genome of S. yellowstonense and S. azorense were found to be active at high temperatures and preserved its activity after immobilization on paramagnetic or polymeric supports. It has been demonstrated that these CAs are good candidates in the CO2 capture process. CAs from the pathogens aforementioned were biochemically characterized and an extensive inhibition profile was carried out using the classical CAs inhibitors such as sulfonamides and anions. These studies have contributed to the search of antibiotics with a novel mechanism of action. Additionally, the present thesis has contributed to the discovery of the η-CA, a new genetic families of CAs; to the introduction of a new technique, named protonography, useful for the identification of CA activity on a polyacrylamide gel; and to the phylogenetic analysis of the α-, β- and γ-CAs identified in the genome of the Gram-positive and Gram-negative bacteria

Clinical applications of TSPO PET for glioma imaging: current evidence and future perspective a systematic review

Our aim was to provide a comprehensive overview of the existing literature concerning the clinical applications of positron emission computed tomography (PET) with radiopharmaceuticals targeting the translocator protein (TSPO) in gliomas. A literature search for studies about TSPO PET in the last 10 years (from 2013 to February 2023) was carried out on PubMed, Scopus, and Web of Science using the following keywords: "PET" AND "Gliomas" AND "TSPO". The Critical Appraisal Skills Program checklist for diagnostic test studies was used for testing the quality of selected papers. Ten articles were selected, encompassing 314 glioma patients submitted to PET/CT (9/10) or PET/MRI (1/10) with TSPO ligands. Among the various available TSPO tracers, the most frequently used was the third-generation ligand, [F-18]-GE-180. TSPO PET results were useful to identify anaplastic transformation in gliomas and for the prognostic stratification of patients bearing homogeneous genetic alterations. When compared to amino-acid PET, TSPO PET with [F-18]-GE-180 presented superior image quality and provided larger and only partially overlapping PET-based volumes. Although biased by some issues (i.e., small sample size, most of the studies coming from the same country), preliminary applications of TSPO PET were encouraging. Further studies are needed to define implications in clinical practice and shape the role of TSPO PET for patients' selection for potential TSPO-targeted molecular therapies

Protonography, a new technique for the analysis of carbonic anhydrase activity.

All proteolytic enzymes, which are able to renature and reacquire the proteolytic activity on a copolymerized substrate, can be analyzed by zymography upon removal of sodium dodecyl sulfate (SDS). Protonography, the new technique described in this study, unlike zymography, allows the detection of a different protein, not a protease, i.e. of the carbonic anhydrase (CA, EC 4.2.1.1) activity on a SDS polyacrylamide gel electrophoresis gel. CAs are zinc-containing enzymes that catalyze the reversible conversion of carbon dioxide to bicarbonate and protons. Hydrogen ions produced during the catalyzed reaction are responsible for the change of color that appears on the gel around the CA band. For this reason, we named the new technique "protonography". The following four salient features characterize this new technique: (a) on the basis of molecular weight markers, recombinant or native CAs with different molecular weights can be detected and quantified rapidly on a single gel; (b) the hydratase activity can be reversibly inhibited by SDS during electrophoresis and recovered by incubating the gel in aqueous Triton X-100; (c) it is possible to separate active oligomeric forms of CAs on the gel enabling their activities to be determined independently of one another. This feature is not possible when using solution assays; and (d) it can be a useful tool to establish if a putative or a newly identified CA in a genome is expressed and enzymatically active. This article outlines the general principles employed in protonography, providing an easy procedure to implement it in laboratories working with CAs. It also presents an overview of its development and current research applications through specific examples

MiR-33a Controls hMSCS Osteoblast Commitment Modulating the Yap/Taz Expression Through EGFR Signaling Regulation

Mesenchymal stromal cells (hMSCs) display a pleiotropic function in bone regeneration. The signaling involved in osteoblast commitment is still not completely understood, and that determines the failure of current therapies being used. In our recent studies, we identified two miRNAs as regulators of hMSCs osteoblast differentiation driving hypoxia signaling and cytoskeletal reorganization. Other signalings involved in this process are epithelial to mesenchymal transition (EMT) and epidermal growth factor receptor (EGFR) signalings through the regulation of Yes-associated protein (YAP)/PDZ-binding motif (TAZ) expression. In the current study, we investigated the role of miR-33a family as a (i) modulator of YAP/TAZ expression and (ii) a regulator of EGFR signaling during osteoblast commitments. Starting from the observation on hMSCs and primary osteoblast cell lines (Nh-Ost) in which EMT genes and miR-33a displayed a specific expression, we performed a gain and loss of function study with miR-33a-5p and 3p on hMSCs cells and Nh-Ost. After 24 h of transfections, we evaluated the modulation of EMT and osteoblast genes expression by qRT-PCR, Western blot, and Osteoimage assays. Through bioinformatic analysis, we identified YAP as the putative target of miR-33a-3p. Its role was investigated by gain and loss of function studies with miR-33a-3p on hMSCs; qRT-PCR and Western blot analyses were also carried out. Finally, the possible role of EGFR signaling in YAP/TAZ modulation by miR-33a-3p expression was evaluated. Human MSCs were treated with EGF-2 and EGFR inhibitor for different time points, and qRT-PCR and Western blot analyses were performed. The above-mentioned methods revealed a balance between miR-33a-5p and miR-33a-3p expression during hMSCs osteoblast differentiation. The human MSCs phenotype was maintained by miR-33a-5p, while the maintenance of the osteoblast phenotype in the Nh-Ost cell model was permitted by miR-33a-3p expression, which regulated YAP/TAZ through the modulation of EGFR signaling. The inhibition of EGFR blocked the effects of miR-33a-3p on YAP/TAZ modulation, favoring the maintenance of hMSCs in a committed phenotype. A new possible personalized therapeutic approach to bone regeneration was discussed, which might be mediated by customizing delivery of miR-33a in simultaneously targeting EGFR and YAP signaling with combined use of drugs

Cloning, expression and purification of the complete domain of the η-carbonic anhydrase from Plasmodium falciparum.

The antimalarial drugs are of fundamental importance in the control of malaria, especially for the lack of efficient treatments and acquired resistance to the existing drugs. For this reason, there is a continuous work in identifying novel, less toxic and effective chemotherapies as well as new therapeutic targets against the causative agents of malaria. In this context, a superfamily of metalloenzymes named carbonic anhydrases (CAs, EC 4.2.1.1) has aroused a great interest as druggable enzymes to limit the development of Plasmodium falciparum gametocytes. CAs catalyze a common reaction in all life domains, the carbon dioxide hydration to bicarbonate and protons (CO2 + H2O HCO3- + H+). P. falciparum synthesizes pyrimidines de novo starting from HCO3-, which is generated from CO2 through the action of the ?-CA identified in the genome of the protozoan. Here, we propose a procedure for the preparation of a wider portion of the protozoan ?-CA, named PfCAdom (358 amino acid residues), with respect to the truncated form prepared by Krungkrai et al. (PfCA1, 235 amino acid residues). The results evidenced that the recombinant PfCAdom, produced as a His-tag fusion protein, was 2.7 times more active with respect the truncated form PfCA1

The extremo-?±-carbonic anhydrase from the thermophilic bacterium Sulfurihydrogenibium azorense is highly inhibited by sulfonamides

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The first activation study of a bacterial carbonic anhydrase (CA). The thermostable ?±-CA from Sulfurihydrogenibium yellowstonense YO3AOP1 is highly activated by amino acids and amines

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The alpha-carbonic anhydrase from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1 is highly susceptible to inhibition by sulfonamides

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Anion inhibition studies of an α-carbonic anhydrase from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1

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Anion inhibition studies of the fastest carbonic anhydrase (CA) known the extremo-CA from the bacterium Sulfurihydrogenibium azorense

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