Comprehensive structural investigation of a potent and selective CXCR4 antagonist via crosslink modification.

Macrocyclization presents a valuable strategy for enhancing the pharmacokinetic and pharmacodynamic profiles of short bioactive peptides. The exploration of various macrocyclic characteristics, such as crosslinking tethers, ring size, and orientation, is generally conducted during the early stages of development. Herein, starting from a potent and selective C-X-C chemokine receptor 4 (CXCR4) cyclic heptapeptide antagonist mimicking the N-terminal region of CXCL12, we demonstrated that the disulfide bridge could be successfully replaced with a side-chain to side-chain lactam bond, which is commonly not enlisted among the conventional disulfide mimetics.

Disulfide bond replacement with non-reducible side chain to tail macrolactamization for the development of potent and selective CXCR4 peptide antagonists endowed with flanking binding sites.

The present study describes a small library of peptides derived from a potent and selective CXCR4 antagonist (3), wherein the native disulfide bond is replaced using a side-chain to tail macrolactamization technique to vary ring size and amino acid composition. The peptides were preliminary assessed for their ability to interfere with the interaction between the receptor and anti-CXCR4 PE-conjugated antibody clone 12G5. Two promising candidates (13 and 17) were identified and further evaluated in aI-CXCL12 competition binding assay, exhibiting IC in the low-nanomolar range.

Ultrasound-assisted Peptide Nucleic Acids synthesis (US-PNAS).

Herein, we developed an innovative and easily accessible solid-phase synthetic protocol for Peptide Nucleic Acid (PNA) oligomers by systematically investigating the ultrasonication effects in all steps of the PNA synthesis (US-PNAS). When compared with standard protocols, the application of the so-obtained US-PNAS approach succeeded in improving the crude product purities and the isolated yields of different PNA, including small or medium-sized oligomers (5-mer and 9-mer), complex purine-rich sequences (like a 5-mer Guanine homoligomer and the telomeric sequence TEL-13) and longer oligomers (such as the 18-mer anti-IVS2-654 PNA and the 23-mer anti-mRNA 155 PNA). Noteworthy, our ultrasound-assisted strategy is compatible with the commercially available PNA monomers and well-established coupling reagents and only requires the use of an ultrasonic bath, which is a simple equipment generally available in most synthetic laboratories.

Tailoring the Structure of Cell Penetrating DNA and RNA Binding Nucleopeptides.

Synthetic nucleic acid interactors represent an exciting research field due to their biotechnological and potential therapeutic applications. The translation of these molecules into drugs is a long and difficult process that justifies the continuous research of new chemotypes endowed with favorable binding, pharmacokinetic and pharmacodynamic properties. In this scenario, we describe the synthesis of two sets of homo-thymine nucleopeptides, in which nucleobases are inserted in a peptide structure, to investigate the role of the underivatized amino acid residue and the distance of the nucleobase from the peptide backbone on the nucleic acid recognition process.

CLIPSing Melanotan-II to Discover Multiple Functionally Selective hMCR Agonists.

The pleiotropic role played by melanocortin receptors (MCRs) in both physiological and pathological processes has stimulated medicinal chemists to develop synthetic agonists/antagonists with improved potency and selectivity. Here, by deploying the Chemical Linkage of Peptide onto Scaffolds strategy, we replaced the lactam cyclization of melanotan II (MT-II), a potent and unselective agonist of human MCRs (hMCRs), with different xylene-derived thioethers. The newly designed peptides displayed binding affinities toward MCRs ranging from the low nanomolar to the sub-micromolar range, highlighting a correlation between the explored linkers and the affinity toward hMCRs.

Impulsivity traits and awareness of motor intention in Parkinson's disease: a proof-of-concept study.

Introduction: In patients with Parkinson's disease (PD), impulsivity is still a matter of investigation. It has been hypothesized that impulsive personality traits may favour impulse control disorder (ICD) onset during dopaminergic therapy. In healthy subjects, a relationship between the awareness of motor intention and impulsive personality traits assessed by the Barratt impulsivity scale (BIS-11) has been reported.

Longitudinal changes in MoCA performances in patients with mild cognitive impairment and small vessel disease. Results from the VMCI-Tuscany Study.

Objectives: The Montreal Cognitive Assessment (MoCA) is a cognitive screening test largely employed in vascular cognitive impairment, but there are no data about MoCA longitudinal changes in patients with cerebral small vessel disease (SVD). We aimed to describe changes in MoCA performance in patients with mild cognitive impairment (MCI) and SVD during a 2-year follow-up, and to evaluate their association with transition to major neurocognitive disorder (NCD).

Materials And Methods: Within the prospective observational VMCI-Tuscany Study, patients with MCI and SVD underwent a comprehensive clinical, neuropsychological, and functional evaluation at baseline, and after 1 and 2 years.

Application of the DSM-5 Criteria for Major Neurocognitive Disorder to Vascular MCI Patients.

Aims: The DSM-5 introduced the term "major neurocognitive disorders" (NCDs) to replace the previous term "dementia." However, psychometric and functional definitions of NCDs are missing. We aimed to apply the DSM-5 criteria for diagnosing the transition to NCD to patients with mild cognitive impairment (MCI) and small vessel disease (SVD), and to define clinically significant thresholds for this transition.

Cerebral microbleeds in patients with mild cognitive impairment and small vessel disease: The Vascular Mild Cognitive Impairment (VMCI)-Tuscany study.

Background And Objectives: Cerebral microbleeds (CMBs) are a neuroimaging expression of small vessel disease (SVD). We investigated in a cohort of SVD patients with mild cognitive impairment (MCI): 1) the reliability of the Microbleed Anatomical Rating Scale (MARS); 2) the burden and location of CMBs and their association with cognitive performances, independent of other clinical and neuroimaging features.

Methods: Patients underwent clinical, neuropsychological (4 cognitive domains), and MRI assessments.

Branch Atheromatous Disease: A Clinically Meaningful, Yet Unproven Concept.

Background: In 1989, Louis Caplan first used the term branch atheromatous disease (BAD) to describe an occlusion or stenosis at the origin of a deep penetrating artery of the brain, associated with a microatheroma or a junctional plaque, and leading to an internal capsule or pontine small infarct. BAD remained an understudied concept for decades. In recent years, the increasing diffusion of high-resolution magnetic resonance imaging (HRMRI) techniques brought new attention to the BAD debate.

White matter microstructural damage and depressive symptoms in patients with mild cognitive impairment and cerebral small vessel disease: the VMCI-Tuscany Study.

Background And Purpose: Disruption of cortical-subcortical circuits related to small vessel disease (SVD) may predispose to depression in the elderly. We aimed to determine the independent association between white matter (WM) microstructural damage, evaluated with diffusion tensor imaging (DTI), and depressive symptoms in a cohort of elderly subjects with mild cognitive impairment (MCI) and SVD.

Methods: The vascular mild cognitive impairment (VMCI)-Tuscany Study is an observational multicentric longitudinal study that enrolled patients with MCI and moderate to severe degrees of WM hyperintensities on MRI.

Operationalizing mild cognitive impairment criteria in small vessel disease: the VMCI-Tuscany Study.

Introduction: Mild cognitive impairment (MCI) prodromic of vascular dementia is expected to have a multidomain profile.

Methods: In a sample of cerebral small vessel disease (SVD) patients, we assessed MCI subtypes distributions according to different operationalization of Winblad criteria and compared the neuroimaging features of single versus multidomain MCI. We applied three MCI diagnostic scenarios in which the cutoffs for objective impairment and the number of considered neuropsychological tests varied.

White matter microstructural damage in small vessel disease is associated with Montreal cognitive assessment but not with mini mental state examination performances: vascular mild cognitive impairment Tuscany study.

Background And Purpose: Montreal Cognitive Assessment (MoCA) has been proposed as a screening tool in vascular cognitive impairment. Diffusion tensor imaging is sensitive to white matter microstructural damage. We investigated if diffusion tensor imaging-derived indices are more strongly associated with performances on MoCA or on the widely used mini mental state examination in patients with mild cognitive impairment and small vessel disease.

Variation in risk factors for recent small subcortical infarcts with infarct size, shape, and location.

Background And Purpose: Lacunar infarction is attributable to a perforating arteriolar abnormality. Possible causes include embolism, atheromatosis, or intrinsic disease. We examined whether the size, shape, or location of the lacunar infarct varied with embolic sources, systemic atheroma, or vascular risk factors.

Delay in presentation after acute ischemic stroke: the Careggi Hospital Stroke Registry.

Intravenous thrombolysis with recombinant tissue-type plasminogen activator is the approved treatment for acute ischemic stroke within 4.5 h from symptoms onset. Evidence suggests the earlier treatment was given, the greater the chance of a favorable outcome.

Risk and Determinants of Dementia in Patients with Mild Cognitive Impairment and Brain Subcortical Vascular Changes: A Study of Clinical, Neuroimaging, and Biological Markers-The VMCI-Tuscany Study: Rationale, Design, and Methodology.

Dementia is one of the most disabling conditions. Alzheimer's disease and vascular dementia (VaD) are the most frequent causes. Subcortical VaD is consequent to deep-brain small vessel disease (SVD) and is the most frequent form of VaD.

Progressive lacunar stroke: review of mechanisms, prognostic features, and putative treatments.

Lacunar stroke is generally considered to have a fair outcome. However 20-30% of patients with lacunar stroke worsen neurologically in hours or days after onset, reaching eventually an unexpectedly severe disability status. In the field of acute stroke, progressive lacunar stroke remains an important unresolved practice problem, because as yet no treatment does exist proven to prevent or halt progression.