Sandra Sigala

Induction of the unfolded protein response by α-synuclein in experimental models of Parkinson's disease.

J. Neurochem. (2011) 116, 588–605.

Opposite effects of dopamine D2 and D3 receptors on learning and memory in the rat.

Mesolimbocortical dopamine plays a role in learning and memory. The specific receptor subtypes mediating the effects of dopamine, however, are still unknown. Dopamine D2, D3 and D4 receptors are expressed in the hippocampus and dopamine D3 receptors are present in the septal area, suggesting that these receptor subtypes can contribute to the behavioral effects of dopamine D2-like receptor agonists. We now investigated the role of dopamine D2 and D3 receptors in learning and memory by using the transient amnesia induced by scopolamine in the passive avoidance test as experimental model. The data strongly suggest that both dopamine D2 and D3 receptors mediate the effects of dopamine on the integrative function of learning and memory. In particular, we show that the non-selective dopamine agonist apomorphine prevents the scopolamine-induced disruption of consolidation of the previously acquired passive avoidance behavior. This effect is mediated by receptors belonging to the dopamine D2 family since it was antagonized by (-)-sulpiride and mimicked by quinpirole. Nafadotride, a relatively selective antagonist for dopamine D3 receptors, antagonized scopolamine-induced memory disruption and potentiated the facilitatory effect of quinpirole. Taken together, these results suggest that the effects of dopamine on memory consolidation are the result of a balance between dopamine D2 receptor-mediated facilitation and dopamine D3 receptor-mediated inhibition, and that dopamine D2 and D3 receptors play opposite roles in the control of the mechanisms leading to memory consolidation.

Differential gene expression of cholinergic muscarinic receptor subtypes in male and female normal human urinary bladder

OBJECTIVES To study the mRNA expression of each muscarinic receptor subtype in bladder areas involved in micturition, such as the bladder dome, neck, and trigone. Our study focused on the analysis of the gene expression of muscarinic receptors in the human male and female urinary bladder. Other than the well-known role of bladder parasympathetic innervation, an extensive study of the muscarinic receptor mRNA distribution in male and female urinary bladder is still lacking. METHODS The study was carried out on 5 female (age 56 +/- 10 years) and 5 male (age 70 +/- 9 years) patients. The patients selected for this study did not have any lower urinary tract symptoms, as determined by International Prostate Symptom Score questionnaire. The mRNAs encoding muscarinic receptor subtypes were assessed by reverse transcription-polymerase chain reaction, followed by Southern blot analysis. RESULTS Using a molecular approach, we demonstrated the presence of all muscarinic receptor subtypes in the different urinary bladder areas involved in micturition; in particular, our data indicated that mRNAs encoding muscarinic receptors are largely expressed in all examined bladder areas, both in men and women, although with some remarkable differences and a peculiar distribution. CONCLUSIONS Our results indicate that the pharmacology of the human bladder may be more complex than previously recognized. Furthermore, the choice to study each biopsy as a single sample and not use a pool of tissues allowed us to point out the individual variability between subjects and sex-related differences in the expression profile of muscarinic receptor subtype mRNAs.

L-α-glycerylphorylcholine antagonizes scopolamine-induced amnesia and enhances hippocampal cholinergic transmission in the rat

The effects of L-alpha-glycerylphosphorylcholine (alpha-GPC) on scopolamine-induced memory impairment and on brain acetylcholine (ACh) synthesis and release were investigated in rats. Oral administration of alpha-GPC 3 h before the behavioural test prevented the learning impairment induced by scopolamine given 30 min before the acquisition of a passive avoidance response. Similarly, retrograde amnesia induced by scopolamine, given immediately after acquisition training, was also completely reversed by the drug. These effects were dose-dependent with a maximum at 300 mg/kg. The mechanism of action of this compound was investigated by measuring hippocampal ACh synthesis and release both in vivo by means of the microdialysis technique and in vitro in tissue slices. alpha-GPC dose dependently increased ACh release with a maximum at 300 mg/kg. In addition, i.v. injection of [14C]alpha-GPC resulted in [14C]ACh formation. The data suggest that the behavioural effects of alpha-GPC may be related to its property to increase hippocampal ACh synthesis and release.

GPNMB/OA protein increases the invasiveness of human metastatic prostate cancer cell lines DU145 and PC3 through MMP-2 and MMP-9 activity

Non-metastatic glycoprotein melanoma protein B (GPNMB), also known as osteoactivin (OA) is expressed in a wide array of tumors and represents an emerging target for drug development. In this study, we investigated the role of GPNMB/OA in the progression of human metastatic DU145 and PC3 prostate cancer cells. GPNMB/OA contribution in PCa malignant phenotype has been analyzed by small interfering RNA-induced GPNMB/OA silencing. We found that following GPNMB/OA silencing the migration capability of both DU145 and PC3 cells, evaluated by using in vitro invasivity assay, as well as the metalloproteinases MMP-2 and MMP-9 activity were equally strongly inhibited. By contrast knocking down GPNMB/OA weakly attenuated cell proliferation rate of DU145, an effect that paralleled with an increase number of apoptotic cells. However, PC3 cell growth seems to be not affected by GPNMB/OA. Together, these data reveal that GPNMB/OA acts as a critical molecular mediator promoting the acquisition of the more aggressive, pro-metastatic phenotype distinctive of human DU145 and PC3 cell lines.

Late-onset Parkinsonism in NFκB/c-Rel-deficient mice

Activation of the nuclear factor κB/c-Rel can increase neuronal resilience to pathological noxae by regulating the expression of pro-survival manganese superoxide dismutase (MnSOD, now known as SOD2) and Bcl-xL genes. We show here that c-Rel-deficient (c-rel−/−) mice developed a Parkinson’s disease-like neuropathology with ageing. At 18 months of age, c-rel−/− mice exhibited a significant loss of dopaminergic neurons in the substantia nigra pars compacta, as assessed by tyrosine hydroxylase-immunoreactivity and Nissl staining. Nigral degeneration was accompanied by a significant loss of dopaminergic terminals and a significant reduction of dopamine and homovanillic acid levels in the striatum. Mice deficient of the c-Rel factor exhibited a marked immunoreactivity for fibrillary α-synuclein in the substantia nigra pars compacta as well as increased expression of divalent metal transporter 1 (DMT1) and iron staining in both the substantia nigra pars compacta and striatum. Aged c-rel−/− mouse brain were characterized by increased microglial reactivity in the basal ganglia, but no astrocytic reaction. In addition, c-rel−/− mice showed age-dependent deficits in locomotor and total activity and various gait-related deficits during a catwalk analysis that were reminiscent of bradykinesia and muscle rigidity. Both locomotor and gait-related deficits recovered in c-rel−/− mice treated with l-3,4-dihydroxyphenylalanine. These data suggest that c-Rel may act as a regulator of the substantia nigra pars compacta resilience to ageing and that aged c-rel−/− mice may be a suitable model of Parkinson’s disease.

Should we be cautious on the use of commercially available antibodies to dopamine receptors

Evidence indicate that it is difficult to obtain specific antibodies to G protein-coupled receptors and different technical difficulties may allow the generation of antibodies that lack specificity. We conducted experiments to validate the specificity of commercially available antibodies raised against dopamine (DA) receptors hD1, hD4, and hD5 using a transfection approach: we studied whether, in HEK 293 cells selectively transfected with the various cloned subtypes, each antibody generates bands only in cells expressing its cognate receptor but not in those expressing the other DA receptors. Our results demonstrated that hD1 and hD4 receptor antibodies recognize not only their respective epitope, but also other DA receptor subtypes, while for the hD5 receptor detection, we observed a signal only in the lane loaded with hD5-transfected HEK 293 cells, although with a lack of purity. Therefore, we recommend caution on the use of commercially available DA receptor antibodies.

Clinical Outcome After Extended Endovascular Recanalization in Buerger’s Disease in 20 Consecutive Cases

BACKGROUND To present our experience of extended endovascular management for thromboangiitis obliterans (Buergers disease) patients with critical limb ischemia (CLI). METHODS Between January 2005 and July 2010, a consecutive series of 17 Buergers disease patients with CLI in 20 limbs were admitted and the diagnosis confirmed. The mean age of the patients was 41.5 years (standard error: ±1.7). All patients presented with history of smoking, one patient presented with hypertension, and eight patients presented with dyslipidemia. According to Rutherford classification, all patients were found to be between grades 3 and 5. Ultrasonography first, and angiography examination later, confirmed a severe arterial disease involving almost exclusively below-the-knee and foot arteries in all cases. A new approach for revascularization, defined as extended angioplasty of each tibial and foot artery obstruction, was performed to achieve direct perfusion of at least one foot artery. RESULTS An extensive endovascular treatment was intended in all patients with success in 19 of 20 limbs, achieving a technical success in 95%. No mortality or complication related to the procedure was observed. During a mean follow-up of 23 months (standard error: ±4.05), amputation-free survival with no need of major amputation in any case and sustained clinical improvement was achieved in 16 of the 19 limbs (84.2%) successfully treated, resulting in a 100% limb salvage rate (19/19). CONCLUSION In this first experience, in patients with thromboangiitis obliterans, extended endovascular intervention was a feasible and effective revascularization procedure in case of CLI. High technical success, amputation-free survival, and sustained clinical improvement rates were achieved at midterm follow-up was achieved.

Correlation between the Overactive Bladder questionnaire (OAB-q) and urodynamic data of Parkinson disease patients affected by neurogenic detrusor overactivity during antimuscarinic treatment.

Introduction: Parkinson disease (PD) patients present urinary symptoms during the course of the disease, very often suggestive of overactive bladder and sustained by neurogenic detrusor overactivity. These symptoms cause a severe lowering of quality of life determining social withdrawal and they need to be early diagnosed to restore social interaction and prevent urinary tract complications. Today overactive bladder diagnosis is easier, thanks to the availability of new investigative tools, particularly voiding questionnaires. The aim of the present study was to evaluate the reliability of the Overactive Bladder screener (OAB screener/OAB-questionnaire), a new voiding questionnaire specifically developed for the overactive bladder diagnosis in PD subjects suffering from overactive bladder symptoms. Clinical data obtained by the questionnaire were compared with urodynamic outcomes, at basal conditions and after antimuscarinic treatment, to better explorate the questionnaire reliability. Materials and Methods: Forty PD patients have been enrolled in the protocol, and submitted to the OAB screener, voiding diary and urodynamic investigation before and after antimuscarinic treatment. OAB-score and urodynamic parameters were statistically analyzed and compared. Results: The OAB-q well correlated with voiding diary and urodynamic data of Parkinson subjects either at baseline or after the antimuscarinic treatment. The study suggests that this clinical tool might be used for neurogenic overactive bladder diagnosis and that it seems to be a useful outcome measure for treatments of neurogenic OAB.

Nerve growth factor signaling in prostate health and disease

The prostate is one of the most abundant sources of nerve growth factor (NGF) in different species, including humans. NGF and its receptors are implicated in the control of prostate cell proliferation and apoptosis and it can either support or suppress cell growth. The co-expression of both NGF receptors, p75NGFR and tropomyosin-related kinase A (trkA), represents a crucial condition for the antiproliferative effect of NGF; indeed, p75NGFR is progressively lost during prostate tumorigenesis and its disappearance represents a malignancy marker of prostate adenocarcinoma (PCa). Interestingly, a dysregulation of NGF signal transduction was found in a number of human tumors. This review summarizes the current knowledge on the role of NGF and its receptors in prostate and in PCa. Conclusions bring to the hypothesis that the NGF network could be a candidate for future pharmacological manipulation in the PCa therapy: in particular the re-expression of p75NTR and/or the negative modulation of trkA could represent a target to induce apoptosis and to reduce proliferation and invasiveness of PCa.