Treatment of kidney clear cell carcinoma, lung adenocarcinoma and glioblastoma cell lines with hydrogels made of DNA nanostars.

Overcoming the systemic administration of chemotherapy to reduce drug toxicity and the application of personalised medicine are two of the major challenges in the treatment of cancer. To this aim, efforts are focused on finding novel nanomaterials for the targeted administration of drugs and bioactive molecules in the tumor sites. DNA-based hydrogels are promising candidates for these applications. However, while such materials are fairly known from a structural and physical standpoint, their effects on cell cultures are far less investigated. Here, we studied the biological response of three different cell lines (clear cell renal cell carcinoma 786-O, lung adenocarcinoma H1975 and glioblastoma U87MG) to the treatment with DNA-GEL - a DNA-based hydrogel composed of interacting DNA nanostars. Additionally, we investigated the structural modification of DNA-GELs under cell culture conditions. The results we collected show a cell type specificity of the response, with interesting implications for future applications.

Spatially uniform dynamics in equilibrium colloidal gels.

Gels of DNA nanostars, besides providing a compatible scaffold for biomedical applications, are ideal model systems for testing the physics of equilibrium colloidal gels. Here, using dynamic light scattering and photon correlation imaging (a recent technique that, by blending light scattering and imaging, provides space-resolved quantification of the dynamics), we follow the process of gel formation over 10 orders of magnitude in time in a model system of tetravalent DNA nanostars in solution, a realization of limited-valence colloids. Such a system, depending on the nanostar concentration, can form either equilibrium or phase separation gels. In stark contrast to the heterogeneity of concentration and dynamics displayed by the phase separation gel, the equilibrium gel shows absence of aging and a remarkable spatially uniform dynamics.

Hyperbranched DNA clusters.

Taking advantage of the base-pairing specificity and tunability of DNA interactions, we investigate the spontaneous formation of hyperbranched clusters starting from purposely designed DNA tetravalent nanostar monomers, encoding in their four sticky ends the desired binding rules. Specifically, we combine molecular dynamics simulations and Dynamic Light Scattering experiments to follow the aggregation process of DNA nanostars at different concentrations and temperatures. At odds with the Flory-Stockmayer predictions, we find that, even when all possible bonds are formed, the system does not reach percolation due to the presence of intracluster bonds. We present an extension of the Flory-Stockmayer theory that properly describes the numerical and experimental results.

DNA-GEL, Novel Nanomaterial for Biomedical Applications and Delivery of Bioactive Molecules.

Novel DNA materials promise unpredictable perspectives for applications in cell biology. The realization of DNA-hydrogels built by a controlled association of DNA nanostars, whose binding can be tuned with minor changes in the nucleotide sequences, has been recently described. DNA hydrogels, with specific gelation properties that can be reassambled in desired culture media supplemented with drugs, RNA, DNA molecules and other bioactive compounds offer the opportunity to develop a novel nanomaterial for the delivery of single or multiple drugs in tumor tissues as an innovative and promising strategy. We provide here a comprehensive description of different, recently realized DNA-gels with the perspective of stimulating their biomedical application. Finally, we discuss the possibility to design sophisticated 3D tissue-like DNA-gels incorporating cell spheroids or single cells for the assembly of a novel kind of cellular matrix as a preclinical investigation for the implementation of tools for in vivo delivery of bioactive molecules.

Thermophoresis in self-associating systems: probing poloxamer micellization by opto-thermal excitation.

Due to its exquisite sensitivity to interfacial properties, thermophoresis, i.e., particle motion driven by thermal gradients, can provide novel, exclusive, and often surprising information on the structural properties of colloidal or macromolecular fluids and on particle/solvent interactions at the nanoscale. Here, by using an all-optical thermal excitation technique, thermal lensing, we show that thermophoresis can be profitably exploited to investigate the self-association of an amphiphilic block copolymer, poloxamer P407, which takes place above a concentration-dependent critical micellization temperature (cmt). In particular we show that, around and above the cmt, the direction of the poloxamer thermophoretic motion displays a remarkable double sign inversion, which is fully correlated with a peak in the thermal expansivity of the solution marking the progressive dehydration of the propylene oxide groups of P407 and their incorporation into the micellar core. This rather puzzling behaviour of the thermophoretic mobility and of the Soret coefficient in the P407 micellization region can tentatively be explained by properly taking into account the temperature-dependent balance between micellized and nonassociated poloxamer chains.

Compressive yield stress of depletion gels from stationary centrifugation profiles.

We have investigated the stationary sedimentation profiles of colloidal gels obtained by an arrested phase-separation process driven by depletion forces, which have been compressed either by natural gravity or by a centrifugal acceleration ranging between 6g and 2300g. Our measurements show that the gel rheological properties display a drastic change when the gel particle volume fraction exceeds a value [Formula: see text], which barely depends on the strength of the interparticle attractive forces that consolidate the network. In particular, the gel compressive yield stress [Formula: see text], which increases as [Formula: see text] for [Formula: see text], displays a diverging behaviour for [Formula: see text], with an asymptotic value that is close to the random close packing value for hard spheres. The evidence we obtained suggests that [Formula: see text] basically coincides with the liquid (colloid-rich) branch of the metastable coexistence curve, rather than with the lower (and ϕ-dependent) values expected for an attractive glass line penetrating inside the coexistence region.

Use of RAFT macro-surfmers for the synthesis of transparent aqueous colloids with tunable interactions.

We propose a new method to produce fluorinated nanoparticles (NPs) based on ab initio reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization without the use of toxic surfactants. NP size, surface charge, and chemistry can be controlled via the adoption of different macromolecular transfer agents produced via RAFT polymerization of amphiphilic monomers. Thanks to this versatility, interparticle interactions can be easily tuned by changing solvent composition and temperature. In addition, the refractive index and density of the solvent can simultaneously match those of the NPs by adding sodium polytungstate, an organic salt widely used for density gradient centrifugation. These colloids may be used as model systems for the study of self-assembly and aggregation in aqueous media when optical methods are required.

Colloidal Swarms Can Settle Faster than Isolated Particles: Enhanced Sedimentation near Phase Separation.

By experimenting on model colloids where depletion forces can be carefully tuned and quantified, we show that attractive interactions consistently "promote" particle settling, so much that the sedimentation velocity of a moderately concentrated dispersion can even exceed its single-particle value. At larger particle volume fraction ϕ, however, hydrodynamic hindrance eventually takes over. Hence, v(ϕ) actually displays a nonmonotonic trend that may threaten the stability of the settling front to thermal perturbations. Finally, by discussing a representative case, we show that these results are relevant to the investigation of protein association effects by ultracentrifugation.

Tardive dyskinesia and DRD2, DRD3, DRD4, 5-HT2A variants in schizophrenia: an association study with repeated assessment.

We performed an association study between four candidate genes, DRD2, DRD3, DRD4 and 5-HT2A for the presence of tardive dyskinesia (TD) on 84 patients with residual schizophrenia. The sample was evaluated again for the presence of TD after an interval of 3 years. The first group did not exhibit TD in either observation (n=34) while in the second group of patients exhibited TD in at least one of the observations (n=20+18). The clinical and socio-demographic characteristics were not significantly different between the two groups; the genetic analysis revealed a significant correlation between the C/C genotype of 5-HT2A and TD (p=0.017). An association trend was observed between the 'short' variant of DRD4 and TD (p=0.022). We did not observe any significant association for the DRD2 and DRD3 polymorphisms.

Genetic dissection of drug effects in clinical practice: CLOCK gene and clozapine-induced diurnal sleepiness.

Psychotic patients treated with clozapine often experience persistent daytime sleepiness. This is a frequent side effect of clozapine that may reduce patient compliance. We hypothesized that clozapine might interfere with the circadian rhythms regulated by the biological clock. In 171 patients with major psychosis, we investigated the association between hypersomnolence during clozapine therapy and a CLOCK gene polymorphism (3111 T/C substitution). Forty-six patients showed persistent daytime sleepiness and were classified as "sleepy". "Sleepy" patients were significantly more likely to have a mutated allele compared to both "non sleepy" patients and healthy subjects (chi2 = 20.36, d.f. = 1, P = 0.000007, and chi2 = 13.91, d.f. = 1, P = 0.0002, respectively). We conclude that an interaction between clozapine and the CLOCK gene polymorphism 3111 T/C substitution could explain persistent daytime sleepiness in a significant proportion of patients treated with clozapine.

Depressive syndrome in major psychoses: a study on 1351 subjects.

The aim of this study was to investigate depressive symptomatology across distinct major psychiatric disorders. A total of 1351 subjects affected by major depressive disorder (MDD = 389), bipolar disorder (BP = 511), delusional disorder (DD = 93) and schizophrenia (SKZ = 358) were included in our study. Subjects were assessed using the Operational Criteria for Psychotic Illness checklist (OPCRIT). The most frequently represented depressive symptoms in MDD were Loss of energy/tiredness, Loss of pleasure, Poor concentration, and Sleep disorders. Compared with MDD, BP had higher occurrences of Agitated activity, Excessive sleep, and Increased appetite and/or Weight gain, as well as lower Loss of pleasure. In our sample, 32.3% and 26.8% of DD and SKZ, respectively, had quite consistent depressive symptomatology, with at least four or more depressive symptoms. The most common depressive symptoms were Sleep disorders, Poor concentration and Loss of energy/Tiredness, followed by Psychomotor symptoms in SKZ only. Excessive self-reproach, Suicidal ideation, and Appetite and/or Weight changes were more specific to mood disorders. Finally, compared with SKZ, DD suffered from more depressive symptoms and had more severe depressive symptomatology. A quite consistent level of depressive symptomatology is therefore present in subpopulations of delusional and schizophrenic subjects other than in affective subjects. We identified some symptoms that are common across all major psychoses and symptoms that are more specific to each group.

Cabergoline treatment of risperidone-induced hyperprolactinemia: a pilot study.

BACKGROUND: D(2) blockers, including the atypical antipsychotic risperidone, induce hyper-prolactinemia in a significant number of patients treated. The endocrine and sexual side effects related to hyperprolactinemia significantly impair tolerability and compliance in patients, including those with a good response to risperidone. This pilot study aimed to evaluate the efficacy and tolerability of a low dose of cabergoline, a D(2) agonist, in the treatment of risperidone-induced hyperprolactinemia. METHOD: Nineteen male and female DSM-IV-defined schizophrenic patients who were clinical responders to risperidone but were suffering from symptomatic hyperprolactinemia were treated with cabergoline, 0.125 to 0.250 mg/week for 8 weeks. Plasma prolactin level was assessed at baseline and at the end of the study. Data were collected from January 2002 to April 2003. RESULTS: After cabergoline treatment, the mean decrease in plasma prolactin levels was statistically significant (p <.05) for the total sample, and 11 patients showed remission of clinical signs with prolactin values within the normal range. No side effect was observed or reported, and the patients' psychopathology was unchanged. CONCLUSIONS: Results suggest that low-dose cabergoline treatment of risperidone-induced hyperprolactinemia may be safe and clinically effective in a relevant number of patients.

Gene-environment interaction in psychiatric disorders as indicated by season of birth variations in tryptophan hydroxylase (TPH), serotonin transporter (5-HTTLPR) and dopamine receptor (DRD4) gene polymorphisms.

Genetic and environmental factors, as well as their interactions, are likely to be involved in psychiatric disorders. Considerable progress has been made in association and linkage studies with various candidate genes, at times with conflicting or ambiguous results. An environmental factor that has persistently shown associations with several psychiatric and neurological disorders is the season of birth. If it is the interaction of a specific gene allele with a specific season of birth that constitutes an increased (or decreased) risk for a disorder, then the individuals with this disorder are likely to have a season of birth variation in this gene allele. We investigated the variations in TPH, 5-HTTLPR and DRD4 gene polymorphisms according to seasonality of birth in 954 patients with unipolar affective disorder, bipolar affective disorder, and schizophrenia, respectively, and in 395 controls. We first analyzed season of birth variations in the gene alleles with one cycle or two cycles per year, and then compared specified birth seasons with each other. We found season of birth variations in these gene alleles that were different for different psychiatric disorders. Significant differences between cases and controls could be obtained when restricting the analysis within certain birth seasons but not within others. Our results thus suggest an interaction between the seasons of birth and the expression of the candidate genes, and that season of birth is a confounding variable when investigating the role of the candidate genes in susceptibility to psychiatric disorders.

Multicentre Italian family-based association study on tyrosine hydroxylase, catechol-O-methyl transferase and Wolfram syndrome 1 polymorphisms in mood disorders.

OBJECTIVE: The aim of the present study was to investigate tyrosine hydroxylase, catechol-O-methyl transferase and Wolfram syndrome 1 genes in mood disorders using a family-based association approach. METHODS: The sample included 134 nuclear mood disorder families, with subjects affected by bipolar disorder (n=103) or major depressive disorder (n=58). All subjects were genotyped using polymerase chain reaction techniques. RESULTS: No significant transmission disequilibrium was found in the overall sample for any polymorphism. Analysis considering bipolar subjects only, or psychopathology traits as affection status did not influence the observed results. CONCLUSIONS: The study could not support the involvement of tyrosine hydroxylase, catechol-O-methyl transferase and Wolfram syndrome 1 polymorphisms in mood disorders.

SSRIs antidepressant activity is influenced by G beta 3 variants.

The aim of the present study was to test a possible effect of the G-protein beta3-subunit (Gbeta3) C825T gene variant on the antidepressant activity of selective serotonin reuptake inhibitors (SSRIs) in a sample of major and bipolar depressives, with or without psychotic features. Four hundred and ninety inpatients were treated with fluvoxamine 300 mg/day (n=362) or paroxetine 40 mg/day (n=128) and either placebo or pindolol in a double-blind design for 6 weeks. The severity of depressive symptoms was weekly assessed with the Hamilton Rating Scale for Depression. Gbeta3 allelic variants were determined in each subject using a PCR-based technique. Subjects with Gbeta3 T/T variants showed better response to treatment (P=0.009) and this effect was independent from analyzed demographic and clinical variables. These results confirm preliminary reports and shed further light on the genetics of the response to antidepressant treatments.

Clinical and demographic features of mood disorder subtypes.

The aim of this study was to investigate demographic, clinical and symptomatologic features of the following mood disorder subtypes: bipolar disorder I (BP-I); bipolar disorder II (BP-II); major depressive disorder, recurrent (MDR); and major depressive episode, single episode (MDSE). A total of 1832 patients with mood disorders (BP-I=863, BP-II=141, MDR=708, and MDSE=120) were included in our study. The patients were assessed using structured diagnostic interviews and the operational criteria for psychotic illness checklist (n=885), the Hamilton depression rating scale (n=167), and the social adjustment scale (n=305). The BP-I patients were younger; had more hospital admissions; presented a more severe form of symptomatology in terms of psychotic symptoms, disorganization, and atypical features; and showed less insight into their disorder than patients in the other groups. Compared with the major depressive subgroups, BP-I patients were more likely to have an earlier age at onset, an earlier first lifetime psychiatric treatment, and a greater number of illness episodes. BP-II patients had a higher suicide risk than both BP-I and MDSE patients. MDSE patients presented less severe symptomatology, lower age at observation, and a higher number of males. The retrospective approach and the selection constraints due to the inclusion criteria are the main limitations of the study. Our data support the view that BP-I disorder is quite different from the remaining mood disorders from a demographic and clinical perspective, with BP-II disorder having an intermediate position to MDR and MDSE, that is, as a less severe disorder. This finding may help in the search for the biological basis of mood disorders.

Rapid cycling mood disorder: clinical and demographic features.

Rapid cycling bipolar disorder is defined as four or more illness episodes per year. We compared demographic, clinical, and symptomatological features of subjects with rapid cycling bipolar disorder (RC) and those with non-rapid-cycling bipolar disorder (NR). Five hundred ninety-five subjects (RC = 275, NR = 320), were included in the study. Subjects were assessed using the Operational Criteria for Psychotic Illness checklist (OPCRIT, n = 496), the Hamilton Rating Scale for Depression (HAMD, n = 47), the Social Adjustment Scale (SAS, n = 160), and the Self-Esteem Scale (SES, n = 160). RC were older at the time of assessment and with more medical illnesses. RC showed a lower risk for psychotic and disorganised features, particularly within bipolar I disorder. Finally, bipolar I RC showed a lower risk for violent suicide attempt. Our findings suggest that rapid cycling bipolar disorder is a condition characterized by less severe psychotic and suicidal features, particularly within bipolar I disorder.

Influence of monoamine oxidase A and serotonin receptor 2A polymorphisms in SSRI antidepressant activity.

The aim of the present study was to test a possible effect of the monoamine oxidase A (MAOA) and serotonin receptor 2A (5-HT-2A) gene variants on the antidepressant activity of fluvoxamine and paroxetine in a sample of major (n = 248) and bipolar (n = 195) depressives, with or without psychotic features. A total of 443 in-patients were treated with 300 mg fluvoxamine (n = 307) or 20-40 mg paroxetine (n = 136) for 6 wk. The severity of depressive symptoms was assessed weekly with the Hamilton Rating Scale for Depression (HAMD). Allele variants were determined in each subject using a PCR-based technique. We observed a marginal association between 5-HT-2A variants and antidepressant response while MAOA genotypes were not associated. Possible stratification factors, such as sex, diagnosis, presence of psychotic features, HAMD scores at baseline, pindolol augmentation and SSRIs plasma levels did not significantly influence the observed results. The investigated MAOA and 5-HT-2A gene variants, therefore, do not seem to play a major role in SSRI antidepressant activity.

Family-based association study of 5-HTTLPR, TPH, MAO-A, and DRD4 polymorphisms in mood disorders.

Variants of the functional polymorphism in the serotonin transporter (upstream regulatory region: 5-HTTLPR), the tryptophan hydroxylase (TPH), the monoamine oxidase A (MAO-A), and the dopamine receptor D4 (DRD4) genes have all been associated with mood disorders. The aim of this study was to test those hypotheses by using a family-based association approach. Both diagnoses and psychopathology were used for phenotype definitions. A total of 134 nuclear families with mood disorders, with probands affected by bipolar (n = 103) or major depressive (n = 58) disorders, were included in the study. All subjects were typed for the above-mentioned gene variants using polymerase chain reaction (PCR) technique. No significant transmission disequilibrium was found in the overall sample for any polymorphism. A separate analysis of bipolar subjects only, or the use of continuous psychopathologic traits as affectation status did not influence the observed results. Our study did not support the involvement of 5-HTTLPR, TPH, MAO-A, or DRD4 polymorphisms in mood disorders.

Association study of MAO-A, COMT, 5-HT2A, DRD2, and DRD4 polymorphisms with illness time course in mood disorders.

The aim of our study was to investigate a possible influence of monoamine oxydase A (MAO-A), catechol-O-methyltransferase (COMT), serotonin receptor 2A (5-HT2A), dopamine receptor D2 (DRD2), and dopamine receptor D4 (DRD4) gene variants on timing of recurrence in mood disorders. Gene variants were determined using PCR-based techniques in 550 inpatients affected by recurrent mood disorders (major depressives: n = 212; bipolars: n = 338), rapid cycling mood disorder (n = 81), and 663 controls. We investigated possible genetic influences by comparing illness time course of subjects subdivided according to genotype using multivariate analysis of variance (MANOVA). We could not observe a significantly different time course. No demographic and clinical variables such as sex, age or polarity of onset, presence of psychotic features, genetic loading, or education level influenced the observed results. Our results suggest that MAO-A, COMT, 5-HT2A, DRD2, and DRD4 gene variants are not involved in susceptibility toward different time courses in mood disorders.