Rac1 and Rac3 have opposite functions in Schwann cells during developmental myelination
Pellegatta, Marta; Berti, Caterina; Hurley, Edward; Palmisano, Marilena; de Curtis, Ivan; Feltri, M Laura; Frick, Luciana R
Small Rho GTPases such as Cdc42 and Rac1 regulate peripheral myelination during development. Deletion of Rac1 in Schwann cell conditional knockout mice causes a delay in the process of radial sorting, followed by hypomyelination as well as defective PAK1 activation and high number of immature Oct6+ Schwann cells. Rac3 has been shown to have redundant, specific and even opposite functions to Rac1 depending on the cell type, age and other factors. In neuronal cells, evidence suggests that Rac3 may oppose Rac1 by disrupting PAK1-GIT1-Paxillin signaling thus preventing cell differentiation and extension of lamellipodia. Therefore, we tested if these Rho GTPases have similar or opposite functions in Schwann cells, by deleting the genes for both proteins in mice during peripheral myelination. At P30, global deletion of Rac3 alleviates the developmental defects on axonal sorting and hypomyelination that are caused by Schwann cell conditional ablation of Rac1. Moreover, Rac3 deletion also reverses the arrest of Schwann cells at the Oct6+ stage and ameliorates the defects in PAK1 phosphorylation observed in Rac1 deficient mice. This partial rescue of the phenotype declines later on with aging. Since double transgenic animals showed dysmyelination without axonal degeneration at P60, we postulate that this deterioration is not likely due to loss of Rac3 in neurons, but it seems to be a Schwann cell-specific defect in the maintenance of myelin.
YAP and TAZ control peripheral myelination and the expression of laminin receptors in Schwann cells
Poitelon, Yannick; Lopez-Anido, Camila; Catignas, Kathleen; Berti, Caterina; Palmisano, Marilena; Williamson, Courtney; Ameroso, Dominique; Abiko, Kansho; Hwang, Yoonchan; Gregorieff, Alex; Wrana, Jeffrey L; Asmani, Mohammadnabi; Zhao, Ruogang; Sim, Fraser James; Wrabetz, Lawrence; Svaren, John; Feltri, Maria Laura
Myelination is essential for nervous system function. Schwann cells interact with neurons and the basal lamina to myelinate axons using known receptors, signals and transcription factors. In contrast, the transcriptional control of axonal sorting and the role of mechanotransduction in myelination are largely unknown. Yap and Taz are effectors of the Hippo pathway that integrate chemical and mechanical signals in cells. We describe a previously unknown role for the Hippo pathway in myelination. Using conditional mutagenesis in mice, we show that Taz is required in Schwann cells for radial sorting and myelination and that Yap is redundant with Taz. Yap and Taz are activated in Schwann cells by mechanical stimuli and regulate Schwann cell proliferation and transcription of basal lamina receptor genes, both necessary for radial sorting of axons and subsequent myelination. These data link transcriptional effectors of the Hippo pathway and of mechanotransduction to myelin formation in Schwann cells.
Diagnosis, assessment and management of delusional jealousy in Parkinson's disease with and without dementia
Perugi, Giulio; Poletti, Michele; Logi, Chiara; Berti, Caterina; Romano, Anna; Del Dotto, Paolo; Lucetti, Claudio; Ceravolo, Roberto; Dell'Osso, Liliana; Bonuccelli, Ubaldo
Patients with Parkinson's disease (PD) may present delusional jealousy (DJ). In a previous cross-sectional prevalence study we identified 15 cognitively preserved and five demented PD patients with DJ. The current study aimed at evaluating their clinical (motor and non-motor) characteristics and the pharmacological treatments associated with DJ, and its subsequent pharmacological management. Patients were assessed by neurologists and psychiatrists using the Hoehn and Yahr scale, the Unified Parkinson's Disease Rating Scale, the Brief Psychiatric Rating Scale, the Beck Depression Inventory, the Hamilton Anxiety Scale and the Neuropsychiatric Inventory. Efficacy of DJ management was evaluated in follow-up visits. All patients were in therapy with dopamine agonists. A subgroup of five cognitively preserved patients developed DJ after a short period of treatment of therapy with dopamine agonists, while other patients developed DJ after a longer period of dopaminergic treatment. Psychiatric comorbidities were common in cognitively preserved and in demented patients. The pharmacological management included the interruption of dopamine agonists in two patients and the reduction of dopamine agonist dose plus the use of antipsychotics in other patients. These clinical data suggest that the management of medicated PD patients should include investigation for the presence of DJ and the evaluation of clinical characteristics potentially relevant to the prevention or the early recognition of delusions.
Relationship between neuropsychiatric symptoms and cognitive performance in de novo Parkinson's disease [Letter]
Poletti, Michele; Lucetti, Claudio; Del Dotto, Paolo; Berti, Caterina; Logi, Chiara; Bonuccelli, Ubaldo
Non-redundant function of dystroglycan and Î²1 integrins in radial sorting of axons
Berti, Caterina; Bartesaghi, Luca; Ghidinelli, Monica; Zambroni, Desirée; Figlia, Gianluca; Chen, Zu-Lin; Quattrini, Angelo; Wrabetz, Lawrence; Feltri, M Laura
Radial sorting allows the segregation of axons by a single Schwann cell (SC) and is a prerequisite for myelination during peripheral nerve development. Radial sorting is impaired in models of human diseases, congenital muscular dystrophy (MDC) 1A, MDC1D and Fukuyama, owing to loss-of-function mutations in the genes coding for laminin Î±2, Large or fukutin glycosyltransferases, respectively. It is not clear which receptor(s) are activated by laminin 211, or glycosylated by Large and fukutin during sorting. Candidates are Î±Î²1 integrins, because their absence phenocopies laminin and glycosyltransferase deficiency, but the topography of the phenotypes is different and Î²1 integrins are not substrates for Large and fukutin. By contrast, deletion of the Large and fukutin substrate dystroglycan does not result in radial sorting defects. Here, we show that absence of dystroglycan in a specific genetic background causes sorting defects with topography identical to that of laminin 211 mutants, and recapitulating the MDC1A, MDC1D and Fukuyama phenotypes. By epistasis studies in mice lacking one or both receptors in SCs, we show that only absence of Î²1 integrins impairs proliferation and survival, and arrests radial sorting at early stages, that Î²1 integrins and dystroglycan activate different pathways, and that the absence of both molecules is synergistic. Thus, the function of dystroglycan and Î²1 integrins is not redundant, but is sequential. These data identify dystroglycan as a functional laminin 211 receptor during axonal sorting and the key substrate relevant to the pathogenesis of glycosyltransferase congenital muscular dystrophies.
A novel role for MuSK and non-canonical Wnt signaling during segmental neural crest cell migration
Banerjee, Santanu; Gordon, Laura; Donn, Thomas M; Berti, Caterina; Moens, Cecilia B; Burden, Steven J; Granato, Michael
Trunk neural crest cells delaminate from the dorsal neural tube as an uninterrupted sheet; however, they convert into segmentally organized streams before migrating through the somitic territory. These neural crest cell streams join the segmental trajectories of pathfinding spinal motor axons, suggesting that interactions between these two cell types might be important for neural crest cell migration. Here, we show that in the zebrafish embryo migration of both neural crest cells and motor axons is temporally synchronized and spatially restricted to the center of the somite, but that motor axons are dispensable for segmental neural crest cell migration. Instead, we find that muscle-specific receptor kinase (MuSK) and its putative ligand Wnt11r are crucial for restricting neural crest cell migration to the center of each somite. Moreover, we find that blocking planar cell polarity (PCP) signaling in somitic muscle cells also results in non-segmental neural crest cell migration. Using an F-actin biosensor we show that in the absence of MuSK neural crest cells fail to retract non-productive leading edges, resulting in non-segmental migration. Finally, we show that MuSK knockout mice display similar neural crest cell migration defects, suggesting a novel, evolutionarily conserved role for MuSK in neural crest migration. We propose that a Wnt11r-MuSK dependent, PCP-like pathway restricts neural crest cells to their segmental path
Postpartum headache due to spontaneous cervical artery dissection [Case Report]
Borelli, Paolo; Baldacci, Filippo; Nuti, Angelo; Lucetti, Claudio; Berti, Caterina; Logi, Chiara; Orlandi, Giovanni; Bonuccelli, Ubaldo
Postpartum headache is quite common and often related to potentially ominous cerebrovascular accidents. As illustrated in previously published reports, spontaneous cervical artery dissection is a rare but possible cause of headache in the postpartum. We provide 2 additional cases to the 19 described so far, including the first ever report of migraine with aura-like symptoms. Additionally, we summarize the literature and we speculate about the possible etiopathological mechanism underlying this condition.
Levodopa response in dementia with lewy bodies: a 1-year follow-up study
Lucetti, Claudio; Logi, Chiara; Del Dotto, Paolo; Berti, Caterina; Ceravolo, Roberto; Baldacci, Filippo; Dolciotti, Cristina; Gambaccini, Gianna; Rossi, Giuseppe; Bonuccelli, Ubaldo
PURPOSE/OBJECTIVE:To evaluate levodopa responsiveness in patients with probable dementia with Lewy bodies (DLB) compared to early Parkinson's disease (PD) patients. METHODS:Twenty four cases with DLB and 21 with PD underwent a baseline assessment with UPDRS (sub-item II and III) and an acute levodopa challenge test. Positive response to acute levodopa test was defined as an improvement of at least 15% in the tapping test, and at least 25% in the walking test and rigidity or tremor score. Subsequently, all patients were treated continuously with levodopa and evaluated after 6 and 12 months by means of UPDRS II/III. RESULTS:Positive response to the acute levodopa test was observed in 55% of DLB patients (acute DLB responders), and in 90% of PD patients (acute PD responders). Acute DLB responders showed increased latency, and reduction of both duration and amplitude of response to acute levodopa in comparison with acute PD responders. At the 6-month follow-up visit, acute DLB responders showed a greater motor benefit compared with acute DLB non-responders. This improvement was similar to that observed in PD patients. However, at 1-year follow-up acute DLB responders showed a faster worsening of UPDRS III scores compared with acute PD responders, implying a reduction of levodopa efficacy. CONCLUSIONS:Positive response to acute levodopa test can occur in DLB patients and may be predictive of long-term benefit of chronic levodopa therapy, although the motor improvement is less impressive than in PD patients.
Decision-making impairment in a patient with new concomitant diagnoses of Parkinson's disease and HIV [Letter]
Poletti, Michele; Baldacci, Filippo; Nuti, Angelo; Lucetti, Claudio; Berti, Caterina; Bonuccelli, Ubaldo
Influences of dopaminergic treatment on motor cortex in Parkinson disease: a MRI/MRS study
Lucetti, Claudio; Del Dotto, Paulo; Gambaccini, Gianna; Ceravolo, Roberto; Logi, Chiara; Berti, Caterina; Rossi, Giuseppe; Bianchi, Maria Cristina; Tosetti, Michela; Murri, Luigi; Bonuccelli, Ubaldo
The objective of this study was to investigate neurochemical and metabolic changes in the motor cortex in a group of de novo Parkinson's disease (PD) patients before and after 6 mo treatment with the dopamine agonist pergolide. Proton magnetic resonance spectroscopy (1H-MRS) has been used to study striatal and cortical metabolism in PD and other parkinsonisms. So far, no studies evaluating possible brain metabolic changes in PD patients before and after dopaminergic therapy have been reported. De novo PD patients (11) and controls (11) underwent clinical evaluation (UPDRS-III motor evaluation) and a first single-voxel 1H-MRS of the motor cortex. 1H-MRS studies were performed using the PROBE-SV System implemented on a 1.5 Tesla Scanner (GE Medical System, Milwaukee, WI). Pergolide was administered up to a dose of 1 mg t.i.d. After 6 mo follow-up, all patients were clinically evaluated and a second single-voxel 1H-MRS was performed. Lower values of Cho/Cr and NAA/Cr ratios were observed in the motor cortex of PD patients compared with controls (P < 0.02 and P < 0.01, respectively). After 6 mo therapy with pergolide (1 mg t.i.d), PD patients showed an improvement in motor performances (P < 0.05) and an increase in Cho/Cr ratios in the motor cortex at the second 1H-MRS evaluation (P < 0.05) was reported. In conclusion, cortical NAA/Cr and Cho/Cr ratios may be impaired in de novo PD. Dopaminergic therapy capable of improving motor function may restore the Cho/Cr ratio in the motor cortex.