Claudia Ricci

Antimicrobial Activity of Novel Dendrimeric Peptides Obtained by Phage Display Selection and Rational Modification

ABSTRACT A large 10-mer phage peptide library was panned against whole Escherichia coli cells, and an antimicrobial peptide (QEKIRVRLSA) was selected. The peptide was synthesized in monomeric and dendrimeric tetrabranched form (multiple antigen peptide [MAP]), which generally allows a dramatic increase of peptide stability to peptidases and proteases. The antibacterial activity of the dendrimeric peptide against E. coli was much higher than that of the monomeric form. Modification of the original sequence, by residue substitution or sequence shortening, produced three different MAPs, M4 (QAKIRVRLSA), M5 (KIRVRLSA), and M6 (QKKIRVRLSA) with enhanced stability to natural degradation and antimicrobial activity against a large panel of gram-negative bacteria. The MICs of the most potent peptide, M6, were as low as 4 to 8 μg/ml against recent clinical isolates of multidrug-resistant Pseudomonas aeruginosa and members of the Enterobacteriaceae. The same dendrimeric peptides showed high stability to blood proteases, low hemolytic activity, and low cytotoxic effects on eukaryotic cells, making them promising candidates for the development of new antibacterial drugs.

Macrophage migration inhibitory factor in the human endometrium : Expression and localization during the menstrual cycle and early pregnancy

Abstract Macrophage migration inhibitory factor (MIF) was discovered as an activated T-lymphocyte-derived protein that inhibits the random migration of macrophages in vitro. Subsequently, knowledge of the physiological actions of MIF was extended to include its role as a proinflammatory cytokine that affects several functions of macrophages and lymphocytes. Previous reports have suggested an involvement of MIF in reproduction. However, no data are currently available on the presence of this cytokine in the human endometrium. In this study, the expression and tissue localization of MIF was evaluated in specimens of cycling endometrium, first trimester placenta bed biopsy, and isolated endometrial glands by Western blot analysis, immunohistochemistry, ELISA, and reverse transcription-polymerase chain reaction. The results demonstrated that MIF is expressed in human endometrium across the menstrual cycle and in early pregnancy. Immunohistochemical localization identified the protein in glandular epithelium, in stromal and predecidualized stromal cells of cycling endometrium, as well as in the decidua of first-trimester placenta. The proinflammatory features and specific actions of MIF on lymphoid cells suggest its potential involvement in several aspects of endometrial physiology.

Stable peptide inhibitors prevent binding of lethal and oedema factors to protective antigen and neutralize anthrax toxin in vivo

The lethal and oedema toxins produced by Bacillus anthracis, the aetiological agent of anthrax, are made by association of protective antigen with lethal and oedema factors and play a major role in the pathogenesis of anthrax. In the present paper, we describe the production of peptide-based specific inhibitors in branched form which inhibit the interaction of protective antigen with lethal and oedema factors and neutralize anthrax toxins in vitro and in vivo. Anti-protective antigen peptides were selected from a phage library by competitive panning with lethal factor. Selected 12-mer peptides were synthesized in tetra-branched form and were systematically modified to obtain peptides with higher affinity and inhibitory efficiency.

Lack of association of PON polymorphisms with sporadic ALS in an Italian population.

Paraoxonase (PON) gene polymorphisms have been associated with susceptibility to sporadic amyotrophic lateral sclerosis (ALS). We have investigated the role of the previously associated single nucleotide polymorphisms rs854560, rs662, and rs6954345 in 350 ALS patients and 376 matched controls from Italy. No significant association was observed at genotype and haplotype level. Our data suggest that PON polymorphisms are not involved in ALS pathogenesis in an Italian population.

D90A-SOD1 mutation in ALS: The first report of heterozygous Italian patients and unusual findings

Among the 140 Cu/Zn superoxide dismutase-1 (SOD1) gene mutations associated with ALS, only D90A, the most prevalent mutation in Europe, has been clearly shown to cause recessive and dominant ALS. Here we first describe two, apparently sporadic, Italian ALS patients heterozygous for the D90A mutation. One patient experienced early sensory involvement, confirmed by nerve biopsy. We review sensory symptoms in SOD1 ALS and discuss its possible origin in D90A heterozygous patients.

Protecting cognition from aging and Alzheimer's disease: a computerized cognitive training combined with reminiscence therapy

The aim of this paper was to assess the efficacy of process‐based cognitive training (pb‐CT) combined with reminiscence therapy (RT) in patients with mild Alzheimers disease (mAD) and mild cognitive impairment (MCI) and in healthy elderly (HE) subjects.

Progestin regulation of 11β-hydroxysteroid dehydrogenase expression in T-47D human breast cancer cells

Abstract This study examined the enzymatic characteristics and steroid regulation of the glucocorticoid-metabolizing enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD) in the human breast cancer cell line T-47D. In cell homogenates, exogenous NAD significantly increased the conversion of corticosterone to 11-dehydrocorticosterone, while NADP was ineffective. There was no conversion of 11-dehydrocorticosterone to corticosterone either with NADH or NADPH demonstrating the lack of reductase activity. In keeping with these results, RT-PCR analysis indicated a mRNA for 11β-HSD2 in T-47D cells, while 11β-HSD1 mRNA levels were undetectable. In T-47D cells treated for 24 h with medroxyprogesterone acetate (MPA), 11β-HSD catalytic activity was elevated 11-fold, while estrone (E 1 ), estradiol (E 2 ) and the synthetic glucocorticoid dexamethasone (DEX) were ineffective. The antiprogestin mifepristone (RU486) acted as a pure antagonist of the progestin-enhanced 11β-HSD activity, but did not exert any agonistic effects of its own. In addition, RT-PCR analysis demonstrated that MPA was a potent inducer of 11β-HSD2 gene expression, increasing the steady-state levels of 11β-HSD2 mRNA. Taken together, these results demonstrate that 11β-HSD2 is the 11β-HSD isoform expressed by T-47D cells under steady-state conditions and suggest the existence of a previously undocumented mechanism of action of progestins in breast cancer cells.

Severe familial ALS with a novel exon 4 mutation (L106F) in the SOD1 gene

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease associated with a positive familial history in 5-10% of ALS cases. Mutations in the superoxide dismutase-1 (SOD1) gene have been found in 12%-23% of patients diagnosed with familial ALS. Here we report a novel mutation in exon 4 of SOD1 gene in a 55-year-old ALS patient belonging to a large Italian family with ALS first clinically described in 1968. In the family the clinical presentation was characterized by relatively early age of onset, spinal onset with proximal distribution weakness, bulbar involvement and a rapid disease course. Molecular analysis showed a heterozygous mutation at codon 106 resulting in a substitution of phenylalanine for leucine in the SOD1 protein (L106F). In analogy with the previously reported L106V mutation, we propose that the L106F causes a relevant destabilization of the protein chain around the mutation site, able to affect the SOD1 monomer and dimer structures suggesting a pathogenic role for this novel mutation.

Impaired intracortical transmission in G2019S leucine rich-repeat kinase Parkinson patients

Objectives: A mutation in leucine‐rich repeat kinase 2 is the most common cause of hereditary Parkinsons disease (PD), yet the neural mechanisms and the circuitry potentially involved are poorly understood.

Biochemical filtering of a protein-protein docking simulation identifies the structure of a complex between a recombinant antibody fragment and alpha-bungarotoxin.

The structural characterization of a complex of alpha-bungarotoxin with a recombinant antibody fragment that mimics the acetylcholine receptor was achieved using docking simulation procedures. To drive the computer simulation towards a limited set of solutions with biological significance, a filter, incorporating general considerations of antigen-antibody interactions, specificity of the selected antibody fragment and results from alpha-bungarotoxin epitope mapping, was adopted. Two similar structures were obtained for the complex, both of them stabilized by cation-pi and hydrophobic interactions due to tyrosilyl residues of the antibody fragment. Site-directed mutagenesis studies, removing each of the latter aromatic residues and causing full inactivation of the interaction process between the antibody fragment and the neurotoxin, support the validity of the calculated structure of the complex.