A nature‐inspired nrf2 activator protects retinal explants from oxidative stress and neurodegeneration

Oxidative stress (OS) plays a key role in retinal dysfunctions and acts as a major trigger of inflammatory and neurodegenerative processes in several retinal diseases. To prevent OS‐induced retinal damage, approaches based on the use of natural compounds are actively investigated. Recently, structural features from curcumin and diallyl sulfide have been combined in a nature‐inspired hybrid (NIH1), which has been described to activate transcription nuclear factor erythroid‐ 2‐related factor‐2 (Nrf2), the master regulator of the antioxidant response, in different cell lines. We tested the antioxidant properties of NIH1 in mouse retinal explants. NIH1 increased Nrf2 nuclear translocation, Nrf2 expression, and both antioxidant enzyme expression and protein levels after 24 h or six days of incubation. Possible toxic effects of NIH1 were excluded since it did not alter the expression of apoptotic or gliotic markers. In OS‐treated retinal explants, NIH1 strengthened the antioxidant response inducing a massive and persistent expression of antioxidant enzymes up to six days of incubation. These effects resulted in prevention of the accumulation of reactive oxygen species, of apoptotic cell death, and of gliotic reactivity. Together, these data indicate that a strategy based on NIH1 to counteract OS could be effective for the treatment of retinal diseases

Toward the renal vesicle: Ultrastructural investigation of the cap mesenchyme splitting process in the developing kidney

Background: A complex sequence of morphogenetic events leads to the development of the adult mouse kidney. In the present study, we investigated the morphological events that characterize the early stages of the mesenchymal-to-epithelial transition of cap mesenchymal cells, analyzing in depth the relationship between cap mesenchymal induction and ureteric bud (UB) branching. Design and methods: Normal kidneys of newborn non-obese diabetic (NOD) mice were excised and prepared for light and electron microscopic examination. Results: Nephrogenesis was evident in the outer portion of the renal cortex of all examined samples. This process was mainly due to the interaction of two primordial derivatives, the ureteric bud and the metanephric mesenchyme. Early renal developmental stages were initially characterized by the formation of a continuous layer of condensed mesenchymal cells around the tips of the ureteric buds. These caps of mesenchymal cells affected the epithelial cells of the underlying ureteric bud, possibly inducing their growth and branching. Conclusions: The present study provides morphological evidence of the reciprocal induction between the ureteric bud and the metanephric mesenchyme showing that the ureteric buds convert mesenchyme to epithelium that in turn stimulates the growth and the branching of the ureteric bud

Nutraceuticals for the treatment of diabetic retinopathy

Diabetic retinopathy (DR) is one of the most common complications of diabetes mellitus and is characterized by degeneration of retinal neurons and neoangiogenesis, causing a severe threat to vision. Nowadays, the principal treatment options for DR are laser photocoagulation, vitreoretinal surgery, or intravitreal injection of drugs targeting vascular endothelial growth factor. However, these treatments only act at advanced stages of DR, have short term efficacy, and cause side effects. Treatment with nutraceuticals (foods providing medical or health benefits) at early stages of DR may represent a reasonable alternative to act upstream of the disease, preventing its progression. In particular, in vitro and in vivo studies have revealed that a variety of nutraceuticals have significant antioxidant and anti-inflammatory properties that may inhibit the early diabetes-driven molecular mechanisms that induce DR, reducing both the neural and vascular damage typical of DR. Although most studies are limited to animal models and there is the problem of low bioavailability for many nutraceuticals, the use of these compounds may represent a natural alternative method to standard DR treatments

CHAPTER 12: Sigma Receptors as New Target for Multiple Sclerosis

In the pharmaceutical panorama aimed at discovering novel therapeutic agents against multiple sclerosis (MS), sigma 1 receptor (S1R) agonists are fit-for-purpose. Indeed, their neuroprotective and neuroplastic activities within neuronal cells, where they modulate several molecular cascades involved in the onset of some central nervous system (CNS) related diseases, such as calcium homeostasis regulation, glutamate excitotoxicity inhibition and oxidative stress control, have been widely elucidated. Additionally, accumulating evidence suggests the involvement of S1R in preventing oligodendrocyte degeneration and neuroinflammation, conditions associated with MS. Relying on the strict correlation between S1R and neurodegeneration, several S1R agonists have been discovered, offering a wide spectrum of pharmaceutical agents endowed with neuroprotective properties. Despite the increasing knowledge of this molecular target, some aspects remain to be clarified, i.e. the identification of endogenous ligands, as well as its mechanism of activation. Nevertheless, the scientific community is spending its efforts to completely characterize S1R and in this context the recent publication of the three-dimensional structure, as well as the putative S1R dimerization or oligomerization, are opening the door towards a major comprehension of the S1R pathophysiological role. Throughout this chapter, we will disclose the old and new insights of this molecular target, demonstrating the high applicability of S1R in MS

Synthesis and characterization of a “clickable” PBR28 TSPO-selective ligand derivative suitable for the functionalization of biodegradable polymer nanoparticles

Reactive microgliosis is a pathological hallmark that accompanies neuronal demise in many neurodegenerative diseases, ranging from acute brain/spinal cord injuries to chronic diseases, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD) and age-related dementia. One strategy to assess and monitor microgliosis is to use positron emission tomography (PET) by exploiting radioligands selective for the 18 kDa translocator protein (TSPO) which is highly upregulated in the brain in pathological conditions. Several TSPO ligands have been developed and validated, so far. Among these, PBR28 has been widely adopted for PET imaging at both preclinical and clinical levels, thanks to its high brain penetration and high selectivity. For this reason, PBR28 represents a good candidate for functionalization strategies, where this ligand could be exploited to drive selective targeting of TSPO-expressing cells. Since the PBR28 structure lacks functional moieties that could be exploited for derivatization, in this work we explored a synthetic pathway for the synthesis of a PBR28 derivative carrying an alkyne group (PBR-alkyne), enabling the fast conjugation of the ligand through azide-alkyne cycloaddition, also known as click-chemistry. As a proof of concept, we demonstrated in silico that the derivatized PBR28 ligand maintains the capability to fit into the TSPO binding pocked, and we successfully exploited PBR-alkyne to decorate zwitterionic biodegradable polymer nanoparticles (NPs) resulting in efficient internalization in cultured microglia-like cell lines

Approaches for multi-gram scale isolation of enantiomers for drug discovery

Introduction: Over the last 30 years, the scientific community has directed its efforts towards the identification of enantioselective approaches to obtain the desired active enantiomer. Accordingly, efficient production of single enantiomers from small to large scale, throughout Drug Discovery (DD) programs, has become of great interest and a fundamental challenge. Areas covered: This review focuses on two fundamental strategies for preparing enantiomers in high yields and with an excellent enantiomeric excess (ee). Separation of racemates, enantioselective synthesis procedures, and integrated approaches have been extensively reviewed, to offer a guide that enables the selection of the suitable methodology for producing pure enantiomers in scales from small to large. Expert opinion: Over the past two decades, drug regulatory agencies have set strict rules on the use of racemates and pure enantiomers, leading to the transformation of the drug market. Indeed, the number of drugs approved as a single enantiomer has exponentially increased, outclassing the racemic compounds. As a consequence, the academia and pharmaceutical companies are eager to develop efficient procedures for obtaining enantiopure compounds on the desired scale

Activation of the protein-tyrosine kinase associated with the bombesin receptor complex in small cell lung carcinomas.

It has been hypothesized that bombesin-like peptides produced by small cell lung carcinomas may sustain deregulated proliferation through an autocrine mechanism. We have shown that the neuropeptide bombesin leads to the activation of a protein-tyrosine kinase that phosphorylates a 115-kDa protein (p115) associated with the bombesin receptor complex in mouse Swiss 3T3 fibroblasts. We now report that phosphotyrosine antibodies recognize a 115-kDa protein, phosphorylated on tyrosine, in four human small cell lung carcinoma cell lines producing bombesin but not in a nonproducer "variant" line. p115 from detergent-treated small cell lung carcinoma cells binds to bombesin-Sepharose and can be phosphorylated on tyrosine in the presence of radiolabeled ATP and Mn2+. As for the p115 immunoprecipitated from mouse fibroblast, the small cell lung carcinoma p115 can be phosphorylated in an immunocomplex kinase assay. However, the latter does not require the presence of exogenous bombesin for activity. Binding data, obtained by using radiolabeled ligand, suggest receptor occupancy in the cell lines producing bombesin. These observations are consistent with the hypothesis that proliferation in some human small cell lung carcinoma lines is under autocrine control, regulated through activation of bombesin receptors

The efficiency of in-situ hybridization on human chromosomes with alphoid DNAs is enhanced by previous digestion with AluI and TaqI

Centromeric alphoid DNAs of human chromosomes 6, 9, 16 and Y were employed to obtain information on the molecular mechanism(s) determining cytological effects produced by digestion in situ with AluI and TaqI restriction enzymes, possibly related to the structure of the above-cited areas. The following cytological and biochemical experiments were carried out using the above-mentioned alphoid sequences as probes: (1) standard in-situ hybridization and in-situ hybridization after chromosome cleavage with AluI/TaqI, and (2) filter hybridization on the DNA fractions obtained from the material solubilized and that retained on the slides after digestion in situ with AluI/TaqI. Biochemical data show that cleavage of alphoid DNAs is not prevented by the peculiar organization of centromeric heterochromatin, but such cleavage is not necessarily followed by complete DNA solubilization. The analysis of alphoid sequence cleavage in naked genomic DNA as well as during digestion of fixed chromosomes shows that (1) AluI cuts more efficiently than TaqI, (2) DNA fragments as large as 3-5 kb can be solubilized, and (3) DNA fragments of the same size are found in both fractions of DNA, i.e. that retained on the chromosomes as well as that solubilized from chromosomes. Cytological data show that previous chromosome digestion, mostly with TaqI, increases the hybridization signal area, suggesting that this fact might be due to (1) chromatin reorganization produced by enzyme attack and/or (2) the presence of alphoid DNAs which might be restricted not only to the kinetochore area but also to para/peri-centromeric heterochromatin. Lastly, centromere DNA solubilization as a consequence of restriction enzyme cleavage seems to vary from chromosome to chromosome, thus suggesting that centromeric regions do not represent a homogeneous class of constitutive heterochromatin