Unveiling the SOD1-mediated ALS phenotype: insights from a comprehensive meta-analysis

BACKGROUND AND OBJECTIVES

Amyotrophic lateral sclerosis associated with mutations in SOD1 (SOD1-ALS) might be susceptible to specific treatment. The aim of the study is to outline the clinical features of SOD1-ALS patients by comparing them to patients without ALS major gene variants and patients with variants in other major ALS genes. Defining SOD1-ALS phenotype may assist clinicians in identifying patients who should be prioritized for genetic testing.

METHODS

We performed an extensive literature research including original studies which reported the clinical features of SOD1-ALS and at least one of the following patient groups: C9ORF72 hexanucleotide repeat expansion (C9-ALS), TARDBP (TARDBP-ALS), FUS (FUS-ALS) or patients without a positive test for a major-ALS gene (N-ALS). A random effects meta-analytic model was applied to clinical data extracted encompassing sex, site and age of onset. To reconstruct individual patient survival data, the published Kaplan-Meier curves were digitized. Data were measured as odds ratio (OR) or standardized mean difference (SMD) as appropriate. Median survival was compared between groups.

RESULTS

Twenty studies met the inclusion criteria. We identified 721 SOD1-ALS, 470 C9-ALS, 183 TARDBP-ALS, 113 FUS-ALS and 2824 N-ALS. SOD1-ALS showed a higher rate of spinal onset compared with N-ALS and C9-ALS (OR = 4.85, 95% CI = 3.04-7.76; OR = 10.47, 95% CI = 4.32-27.87) and an earlier onset compared with N-ALS (SMD = - 0.45, 95% CI = - 0.72 to - 0.18). SOD1-ALS had a similar survival compared with N-ALS (p = 0.14), a longer survival compared with C9-ALS (p < 0.01) and FUS-ALS (p = 0.019) and a shorter survival compared with TARDBP-ALS (p < 0.01).

DISCUSSION

This study indicates the presence of a specific SOD1-ALS phenotype. Insights in SOD1-ALS clinical features are important in genetic counseling, disease prognosis and support patients' stratification in clinical trials.

HyperPUT: generating synthetic faulty programs to challenge bug-finding tools

As research in automatically detecting bugs grows and produces new techniques, having suitable collections of programs with known bugs becomes crucial to reliably and meaningfully compare the effectiveness of these techniques. Most of the existing approaches rely on benchmarks collecting manually curated real-world bugs, or synthetic bugs seeded into real-world programs. Using real-world programs entails that extending the existing benchmarks or creating new ones remains a complex time-consuming task. In this paper, we propose a complementary approach that automatically generates programs with seeded bugs. Our technique, called HyperPUT, builds C programs from a "seed" bug by incrementally applying program transformations (introducing programming constructs such as conditionals, loops, etc.) until a program of the desired size is generated. In our experimental evaluation, we demonstrate how HyperPUT can generate buggy programs that can challenge in different ways the capabilities of modern bug-finding tools, and some of whose characteristics are comparable to those of bugs in existing benchmarks. These results suggest that HyperPUT can be a useful tool to support further research in bug-finding techniques-in particular their empirical evaluation.

Clinical Features and Biomarkers to Differentiate Primary and Amyotrophic Lateral Sclerosis in Patients With an Upper Motor Neuron Syndrome

OBJECTIVES

Differentiation between primary (PLS) and amyotrophic lateral sclerosis (ALS) entails relevant consequences for prognosis and management but is mostly unreliable at early stages. The objectives of the study are (1) to determine the features at onset that could help to differentiate between PLS and ALS, (2) to evaluate the diagnostic performance of an integrated serum biomarker panel, and (3) to identify the prognostic factors for patients presenting with upper motor neuron (UMN) syndrome.

METHODS

We selected and retrospectively analyzed the clinical data of patients presenting with UMN syndrome. At the first evaluation, when available, serum biomarkers were measured using ultrasensitive single molecule array.

RESULTS

The study population included 55 patients with PLS and 50 patients with ALS. Patients with PLS presented a longer time to first neurologic evaluation (PLS: 35.0 months, interquartile range [IQR] 17.0-38.0 months; ALS: 12.5 months, IQR 7.0-21.3 months; p < 0.01) and lower levels of neurofilament light chain (NfL) (PLS: 81.8 pg/mL, IQR 38.4-111.1 pg/mL; ALS: 155.9 pg/mL, IQR 85.1-366.4 pg/mL; p = 0.01). Two patients with PLS and 3 patients with ALS carried the C9orf72 expansion. NfL resulted an independent predictor of final diagnosis (odds ratio 1.01, 95% CI 1.00-1.02; p = 0.04) and an independent prognostic factor (hazard ratio 1.01, 95% CI 1.00-1.01; p < 0.01).

DISCUSSION

NfL might help to differentiate patients with PLS from patients with ALS and to predict prognosis in patients with UMN syndrome.

A novel GRN mutation in an Italian patient with non-fluent variant of primary progressive aphasia at onset: a longitudinal case report

Objectives

We report the clinical presentation and evolution of a case with a novel Progranulin gene (GRN) mutation and non-fluent language disturbances at onset.

Materials and methods

A 60 year-old, white patient was followed due to a history of language disturbances. Eighteen months after onset, the patient underwent FDG positron emission tomography (PET), and at month 24 was hospitalized to perform neuropsychological evaluation, brain 3 T MRI, lumbar puncture for cerebrospinal fluid (CSF) analysis, and genotyping. At month 31, the patient repeated the neuropsychological evaluation and brain MRI.

Results

At onset the patient complained prominent language production difficulties, such as effortful speech and anomia. At month 18, FDG-PET showed left fronto-temporal and striatal hypometabolism. At month 24, the neuropsychological evaluation reported prevalent speech and comprehension deficits. Brain MRI reported left fronto-opercular and striatal atrophy, and left frontal periventricular white matter hyperintensities (WMHs). Increased CSF total tau level was observed. Genotyping revealed a new GRN c.1018delC (p.H340TfsX21) mutation. The patient received a diagnosis of non-fluent variant of primary progressive aphasia (nfvPPA). At month 31, language deficits worsened, together with attention and executive functions. The patient presented also with behavioral disturbances, and a progressive atrophy in the left frontal-opercular and temporo-mesial region.

Discussion and conclusion

The new GRN p.H340TfsX21 mutation resulted in a case of nfvPPA characterized by fronto-temporal and striatal alterations, typical frontal asymmetric WMHs, and a fast progression toward a widespread cognitive and behavioral impairment, which reflects a frontotemporal lobar degeneration. Our findings extend the current knowledge of the phenotypic heterogeneity among GRN mutation carriers.

Clinical and pathological findings in neurolymphomatosis: Preliminary association with gene expression profiles in sural nerves

Although inflammation appears to play a role in neurolymphomatosis (NL), the mechanisms leading to degeneration in the peripheral nervous system are poorly understood. The purpose of this exploratory study was to identify molecular pathways underlying NL pathogenesis, combining clinical and neuropathological investigation with gene expression (GE) studies. We characterized the clinical and pathological features of eight patients with NL. We further analysed GE changes in sural nerve biopsies obtained from a subgroup of NL patients (n=3) and thirteen patients with inflammatory neuropathies as neuropathic controls. Based on the neuropathic symptoms and signs, NL patients were classified into three forms of neuropathy: chronic symmetrical sensorimotor polyneuropathy (SMPN, n=3), multiple mononeuropathy (MN, n=4) and acute motor-sensory axonal neuropathy (AMSAN, n=1). Predominantly diffuse malignant cells infiltration of epineurium was present in chronic SMPN, whereas endoneurial perivascular cells invasion was observed in MN. In contrast, diffuse endoneurium malignant cells localization occurred in AMSAN. We identified alterations in the expression of 1266 genes, with 115 up-regulated and 1151 down-regulated genes, which were mainly associated with ribosomal proteins (RP) and olfactory receptors (OR) signaling pathways, respectively. Among the top up-regulated genes were actin alpha 1 skeletal muscle (ACTA1) and desmin (DES). Similarly, in NL nerves ACTA1, DES and several RPs were highly expressed, associated with endothelial cells and pericytes abnormalities. Peripheral nerve involvement may be due to conversion towards a more aggressive phenotype, potentially explaining the poor prognosis. The candidate genes reported in this study may be a source of clinical biomarkers for NL.

Profiling morphologic MRI features of motor neuron disease caused by TARDBP mutations

Objective

Mutations in the TARDBP gene are a rare cause of genetic motor neuron disease (MND). Morphologic MRI characteristics of MND patients carrying this mutation have been poorly described. Our objective was to investigate distinctive clinical and MRI features of a relatively large sample of MND patients carrying TARDBP mutations.

Methods

Eleven MND patients carrying a TARDBP mutation were enrolled. Eleven patients with sporadic MND (sMND) and no genetic mutations were also selected and individually matched by age, sex, clinical presentation and disease severity, along with 22 healthy controls. Patients underwent clinical and cognitive evaluations, as well as 3D T1-weighted and diffusion tensor (DT) MRI on a 3 Tesla scanner. Gray matter (GM) atrophy was first investigated at a whole-brain level using voxel-based morphometry (VBM). GM volumes and DT MRI metrics of the main white matter (WM) tracts were also obtained. Clinical, cognitive and MRI features were compared between groups.

Results

MND with TARDBP mutations was associated with all possible clinical phenotypes, including isolated upper/lower motor neuron involvement, with no predilection for bulbar or limb involvement at presentation. Greater impairment at naming tasks was found in TARDBP mutation carriers compared with sMND. VBM analysis showed significant atrophy of the right lateral parietal cortex in TARDBP patients, compared with controls. A distinctive reduction of GM volumes was found in the left precuneus and right angular gyrus of TARDBP patients compared to controls. WM microstructural damage of the corticospinal tract (CST) and inferior longitudinal fasciculi (ILF) was found in both sMND and TARDBP patients, compared with controls, although decreased fractional anisotropy of the right CST and increased axial diffusivity of the left ILF (p = 0.017) was detected only in TARDBP mutation carriers.

Conclusions

TARDBP patients showed a distinctive parietal pattern of cortical atrophy and greater damage of motor and extra-motor WM tracts compared with controls, which sMND patients matched for disease severity and clinical presentation were lacking. Our findings suggest that TDP-43 pathology due to TARDBP mutations may cause deeper morphologic alterations in both GM and WM.

Hand grip support for rehabilitation and assistance: from patent to TRL5

In the last decades, the continuous increase in the number of the vast cohort of chronic patients that constantly need medical assistance and supervision, and the widespread lack of therapist has brought to an increased interest in the role of medical technologies in rehabilitative programs and assistive scenarios. Current clinical evidence in rehabilitation demonstrates that there is an important and increasing demand for innovative therapeutic solutions to recover the hand functions to prevent patients to need assistance in performing daily life activities. This works describes the pathway from patent to TRL5 of a device to support hand grip actions and interaction with daily life objects. E-KIRO is based on the use of electromagnets, which are able to attach/detach interactive objects equipped with a ferromagnetic plate. Five end-users used the device and scored it with excellent usability based on the System Usability Scale.

Integrated evaluation of a panel of neurochemical biomarkers to optimize diagnosis and prognosis in amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

This study was undertaken to determine the diagnostic and prognostic value of a panel of serum biomarkers and to correlate their concentrations with several clinical parameters in a large cohort of patients with amyotrophic lateral sclerosis (ALS).

METHODS

One hundred forty-three consecutive patients with ALS and a control cohort consisting of 70 patients with other neurodegenerative disorders (DEG), 70 patients with ALS mimic disorders (ALSmd), and 45 healthy controls (HC) were included. Serum neurofilament light chain (NfL), ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1), glial fibrillary acidic protein (GFAP), and total tau protein levels were measured using ultrasensitive single molecule array.

RESULTS

NfL correlated with disease progression rate (p < 0.001) and with the measures of upper motor neuron burden (p < 0.001). NfL was higher in the ALS patients with classic and pyramidal phenotype. GFAP was raised in ALS with cognitive-behavioral impairment compared with ALS with normal cognition. NfL displayed the best diagnostic performance in discriminating ALS from HC (area under the curve [AUC] = 0.990), DEG (AUC = 0.946), and ALSmd (AUC = 0.850). UCHL1 performed well in distinguishing ALS from HC (AUC = 0.761), whereas it was not helpful in differentiating ALS from DEG and ALSmd. In multivariate analysis, NfL (p < 0.001) and UCHL1 (p = 0.038) were independent prognostic factors. Survival analysis combining NfL and UCHL1 effectively stratified patients with lower NfL levels (p < 0.001).

CONCLUSIONS

NfL is a useful biomarker for the diagnosis of ALS and the strongest predictor of survival. UCHL1 is an independent prognostic factor helpful in stratifying survival in patients with low NfL levels, likely to have slowly progressive disease. GFAP reflects extramotor involvement, namely cognitive impairment or frontotemporal dementia.

NEK1 Variants in a Cohort of Italian Patients With Amyotrophic Lateral Sclerosis

Introduction

In the last few years, different studies highlighted a significant enrichment of NEK1 loss of function (LoF) variants in amyotrophic lateral sclerosis (ALS), and an additional role for the p.Arg261His missense variant in the disease susceptibility. Several other missense variants have been described so far, whose pathogenic relevance remains however unclear since many of them have been reported in both patients and controls. This study aimed to investigate the presence of NEK1 variants and their correlation with phenotype in a cohort of Italian patients with ALS.

Methods

We sequenced a cohort of 350 unrelated Italian patients with ALS by next-generation sequencing (NGS) and then we analyzed the clinical features of NEK1 carriers.

Results

We detected 20 different NEK1 rare variants (four LoF and 16 missense) in 33 unrelated patients with sporadic ALS (sALS). The four LoF variants (two frameshift and two splice-site variants) were all novel. The p.Arg261His missense variant was enriched in the patients’ cohort (p < 0.001). Excluding this variant from counting, the difference in the frequency of NEK1 rare missense variants between patients and controls was not statistically significant. NEK1 carriers had a higher frequency of flail arm (FA) phenotype compared with the other patients of the cohort (29.2% vs. 6.4%). Nine NEK1 carriers (37.5%) also harbored variants in other ALS-related genes.

Conclusion

This study confirms that NEK1 LoF and p.Arg261. His missense variants are associated with ALS in an Italian ALS cohort and suggests a correlation between the presence of NEK1 variants and FA phenotype.

Current application of neurofilaments in amyotrophic lateral sclerosis and future perspectives

Motor neuron disease includes a heterogeneous group of relentless progressive neurological disorders defined and characterized by the degeneration of motor neurons. Amyotrophic lateral sclerosis is the most common and aggressive form of motor neuron disease with no effective treatment so far. Unfortunately, diagnostic and prognostic biomarkers are lacking in clinical practice. Neurofilaments are fundamental structural components of the axons and neurofilament light chain and phosphorylated neurofilament heavy chain can be measured in both cerebrospinal fluid and serum. Neurofilament light chain and phosphorylated neurofilament heavy chain levels are elevated in amyotrophic lateral sclerosis, reflecting the extensive damage of motor neurons and axons. Hence, neurofilaments are now increasingly recognized as the most promising candidate biomarker in amyotrophic lateral sclerosis. The potential usefulness of neurofilaments regards various aspects, including diagnosis, prognosis, patient stratification in clinical trials and evaluation of treatment response. In this review paper, we review the body of literature about neurofilaments measurement in amyotrophic lateral sclerosis. We also discuss the open issues concerning the use of neurofilaments clinical practice, as no overall guideline exists to date; finally, we address the most recent evidence and future perspectives.

Serum phosphorylated neurofilament heavy-chain levels reflect phenotypic heterogeneity and are an independent predictor of survival in motor neuron disease

To investigate the prognostic role and the major determinants of serum phosphorylated neurofilament heavy -chain (pNfH) concentration across a large cohort of motor neuron disease (MND) phenotypes. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum pNfH concentration in 219 MND patients consecutively enrolled in our tertiary MND clinic. A multifactorial analysis was carried out to investigate the major clinical determinants of serum pNfH. Kaplan–Meier survival curves and Cox regression analysis were performed to explore the prognostic value of serum pNfH. Serum pNfH levels were not homogenous among MND phenotypes; higher concentrations in pyramidal, bulbar, and classic phenotypes were observed. C9orf72-MND exhibited higher pNfH concentrations compared to non-C9orf72 MND. Multiple linear regression analysis revealed mean MEP/cMAP and disease progression rate as the two major predictors of serum pNfH levels (R² = 0.188; p ≤ 0.001). Kaplan–Meier curves showed a significant difference of survival among MND subgroups when divided into quartiles based on pNfH concentrations, log-rank X² = 53.0, p ≤ 0.0001. Our study evidenced that higher serum pNfH concentration is a negative independent prognostic factor for survival. In Cox multivariate model, pNfH concentration showed the highest hazard ratio compared to the other factors influencing survival included in the analysis. pNfH differs among the MND phenotypes and is an independent prognostic factor for survival. This study provides supporting evidence of the role of pNfH as useful prognostic biomarker for MND patients. Neurofilament measurements should be considered in the future prognostic models and in clinical trials for biomarker-based stratification, and to evaluate treatment response.

Coexistence of variants in TBK1 and in other ALS-related genes elucidates an oligogenic model of pathogenesis in sporadic ALS

Variants in tank-binding kinase 1 (TBK1) are responsible for a significant proportion of amyotrophic lateral sclerosis (ALS) cases. In the present study, we analyzed variants in TBK1 extracted by targeted sequencing of 32 genes in a group of 406 Italian patients with ALS. We identified 7 different TBK1 variants in 7 sporadic cases, resulting in a frequency of 1.7%. Three patients had missense variants (p.R357Q, p.R358H, and p.R724C), one patient had a small deletion (p.E618del), and 3 had truncating variants (p.Y482*, p.R229*, and p.N681*). Notably, we found that 4 patients had an additional variant in ALS-related genes: 2 in OPTN and 2 in the 3'UTR region of FUS. By studying an independent group of 7 TBK1-mutated patients previously reported, we found another variant in the 3'UTR region of FUS in one patient. The presence of a second variant in TBK1 variant carriers is an interesting finding that needs to be investigated in larger cohorts of patients. These findings suggest that TBK1 belongs to the category of genes conferring a significantly increased risk but not sufficient to cause disease.

TBK1 mutations in Italian patients with amyotrophic lateral sclerosis: genetic and functional characterisation

BACKGROUND

TANK-binding kinase 1 (TBK1) gene has been recently identified as a causative gene of amyotrophic lateral sclerosis (ALS).

METHODS

We sequenced the TBK1 gene in a cohort of 154 Italian patients with ALS with unclear genetic aetiology. We subsequently assessed the pathogenic potential of novel identified TBK1 variants using functional in vitro studies: expression, targeting and activity were evaluated in patient-derived fibroblasts and in cells transfected with mutated-TBK1 plasmids.

RESULTS

We identified novel genomic TBK1 variants including two loss-of-function (LoF) (p.Leu59Phefs*16 and c.358+5G>A), two missense (p.Asp118Asn and p.Ile397Thr) and one intronic variant (c.1644-5_1644-2delAATA), in addition to two previously reported pathogenetic missense variants (p.Lys291Glu and p.Arg357Gln). Functional studies in patient-derived fibroblasts revealed that the c.358+5G>A causes aberrant pre-mRNA processing leading TBK1 haploinsufficiency. Biochemical studies in cellular models showed that the truncating variant p.Leu59Phefs*16 abolishes TBK1 protein expression, whereas the p.Asp118Asn variant severely impairs TBK1 phosphorylation activity. Conversely, the p.Ile397Thr variant displayed enhanced phosphorylation activity, whose biological relevance is not clear.

CONCLUSION

The observed frequency of TBK1 LoF variants was 1.3% (2/154), increasing up to 3.2% (5/154) by taking into account also the functional missense variants that we were able to classify as potentially pathogenic, supporting the relevance of TBK1 in the Italian population with ALS.

Nitric oxide controls fat deposition in dystrophic skeletal muscle by regulating fibro-adipogenic precursor differentiation

Duchenne muscular dystrophy (DMD) is an hereditary disease characterized by loss of muscle fibers and their progressive substitution by fat and fibrous tissue. Mesenchymal fibro-adipogenic progenitors (FAPs) expressing the platelet-derived growth factor receptor alpha (PDGFRα) are an important source of fibrosis and adipogenesis in dystrophic skeletal muscle. Among the therapies suggested for dystrophy are those based on nitric oxide (NO) donating drugs, the administration of which slows disease progression. NO has been shown to act by enhancing the regenerative potential of the diseased muscle. Whether it acts also by inhibiting fibrosis and adipogenesis was not known. Here, we show in vitro that NO regulates FAP fate through inhibition of their differentiation into adipocytes. In mdx mice, an animal model of DMD, treatment with the NO donating drug molsidomine reduced the number of PDGFRα(+) cells as well as the deposition of both skeletal muscle fat and connective tissues. Inhibition of adipogenesis was due to NO-induced increased expression of miR-27b leading to downregulation of peroxisome proliferator-activated receptors gamma (Pparγ1) expression in a pathway independent of cGMP generation. These findings reveal an additional effect of NO in dystrophic muscle that conceivably synergizes with its known effects on regeneration improvement and explain why NO-based therapies appear effective in the treatment of muscular dystrophy.

A whole-brain atlas of inputs to serotonergic neurons of the dorsal and median raphe nuclei

The serotonin system is proposed to regulate physiology and behavior and to underlie mood disorders; nevertheless, the circuitry controlling serotonergic neurons remains uncharacterized. We therefore generated a comprehensive whole-brain atlas defining the monosynaptic inputs onto forebrain-projecting serotonergic neurons of dorsal versus median raphe based on a genetically restricted transsynaptic retrograde tracing strategy. We identified discrete inputs onto serotonergic neurons from forebrain and brainstem neurons, with specific inputs from hypothalamus, cortex, basal ganglia, and midbrain, displaying a greater than anticipated complexity and diversity in cell-type-specific connectivity. We identified and functionally confirmed monosynaptic glutamatergic inputs from prefrontal cortex and lateral habenula onto serotonergic neurons as well as a direct GABAergic input from striatal projection neurons. In summary, our findings emphasize the role of hyperdirect inputs to serotonergic neurons. Cell-type-specific classification of connectivity patterns will allow for further functional analysis of the diverse but specific inputs that control serotonergic neurons during behavior.

Mice lacking NMDA receptors in parvalbumin neurons display normal depression-related behavior and response to antidepressant action of NMDAR antagonists

The underlying circuit imbalance in major depression remains unknown and current therapies remain inadequate for a large group of patients. Discovery of the rapid antidepressant effects of ketamine - an NMDA receptor (NMDAR) antagonist – has linked the glutamatergic system to depression. Interestingly, dysfunction in the inhibitory GABAergic system has also been proposed to underlie depression and deficits linked to GABAergic neurons have been found with human imaging and in post-mortem material from depressed patients. Parvalbumin-expressing (PV) GABAergic interneurons regulate local circuit function through perisomatic inhibition and their activity is NMDAR-dependent, providing a possible link between NMDAR and the inhibitory system in the antidepressant effect of ketamine. We have therefore investigated the role of the NMDAR-dependent activity of PV interneurons for the development of depression-like behavior as well as for the response to rapid antidepressant effects of NMDAR antagonists. We used mutant mice lacking NMDA neurotransmission specifically in PV neurons (PV-Cre+/NR1f/f) and analyzed depression-like behavior and anhedonia. To study the acute and sustained effects of a single NMDAR antagonist administration, we established a behavioral paradigm of repeated exposure to forced swimming test (FST). We did not observe altered behavioral responses in the repeated FST or in a sucrose preference test in mutant mice. In addition, the behavioral response to administration of NMDAR antagonists was not significantly altered in mutant PV-Cre+/NR1f/f mice. Our results show that NMDA-dependent neurotransmission in PV neurons is not necessary to regulate depression-like behaviors, and in addition that NMDARs on PV neurons are not a direct target for the NMDAR-induced antidepressant effects of ketamine and MK801.

Dosimetry in the therapy of metastatic differentiated thyroid cancer administering high 131I activity: the experience of Busto Arsizio Hospital (Italy)

AIM

The purpose of the present work was to evaluate the impact of 131I high activity therapy treatments of metastatic differentiated thyroid cancer (MDTC) in terms of feasibility, tolerance, efficacy, and the impact of dosimetry in order to optimize the process.

METHODS

Seventeen MDTC patients underwent 27 treatments with 131I, with activity ranging from 6.2 GBq to 24.1 GBq. Red marrow (RM) peritherapy dosimetry was based on the Standard Operating Procedure of European Association of Nuclear Medicine (EANM SOP), while metastases dosimetry on the guidelines of Italian Association of Physicists in Medicine and Italian Association of Nuclear Medicine. In 12 cases prospective dosimetry was performed too, with the purpose of evaluating the possibility of maximizing the therapeutic activity, complying the 2 Gy red marrow (RM) dose constraint. The absorbed dose to 45 lesions was evaluated. The severity of myelotoxic effects was monitored during the follow-up.

RESULTS

Treatments were generally well tolerated, also at the highest RM absorbed doses. RM absorbed doses ranged from 0.49 to 6.67 Gy, lesion doses from 1.1 Gy to 778 Gy. In case of repeated treatments on the same site, in 13 cases on a total of 15, an absorbed dose reduction was observed. RM prospective and peritherapeutic dosimetry differed somewhat: absorbed doses measured during therapy ranged from -7% to +40% with respect to provisional absorbed doses.

CONCLUSION

In our experience high activity treatments were well-tolerated. Prospective dosimetry needs further investigation to become sufficiently reliable in order to comply the 2 Gy constraint. Lesions became progressively less iodine-avid in case of repeated treatments, so the "first big-shoot" treatment with the highest safe activity seems to be desirable to obtain the maximum efficacy.

c-Jun N-terminal kinase regulates soluble Aβ oligomers and cognitive impairment in AD mouse model

Alzheimer disease (AD) is characterized by cognitive impairment that starts with memory loss to end in dementia. Loss of synapses and synaptic dysfunction are closely associated with cognitive impairment in AD patients. Biochemical and pathological evidence suggests that soluble Aβ oligomers correlate with cognitive impairment. Here, we used the TgCRND8 AD mouse model to investigate the role of JNK in long term memory deficits. TgCRND8 mice were chronically treated with the cell-penetrating c-Jun N-terminal kinase inhibitor peptide (D-JNKI1). D-JNKI1, preventing JNK action, completely rescued memory impairments (behavioral studies) as well as the long term potentiation deficits of TgCRND8 mice. Moreover, D-JNKI1 inhibited APP phosphorylation in Thr-668 and reduced the amyloidogenic cleavage of APP and Aβ oligomers in brain parenchyma of treated mice. In conclusion, by regulating key pathogenic mechanisms of AD, JNK might hold promise as innovative therapeutic target.

Distinct Changes in CREB Phosphorylation in Frontal Cortex and Striatum During Contingent and Non-Contingent Performance of a Visual Attention Task

The cyclic-adenosine monophosphate response element-binding protein (CREB) family of transcription factors has been implicated in numerous forms of behavioral plasticity. We investigated CREB phosphorylation along some nodes of corticostriatal circuitry such as frontal cortex (FC) and dorsal (caudate-putamen, CPu) and ventral (nucleus accumbens, NAC) striatum in response to the contingent or non-contingent performance of the five-choice serial reaction time task (5-CSRTT) used to assess visuospatial attention. Three experimental manipulations were used; an attentional performance group (contingent, "master"), a group trained previously on the task but for whom the instrumental contingency coupling responding with stimulus detection and reward was abolished (non-contingent, "yoked") and a control group matched for food deprivation and exposure to the test apparatus (untrained). Rats trained on the 5-CSRTT (both master and yoked) had higher levels of CREB protein in the FC, CPu, and NAC compared to untrained controls. Despite the divergent behavior of "master" and "yoked" rats CREB activity in the FC was not substantially different. In rats performing the 5-CSRTT ("master"), CREB activity was completely abolished in the CPu whereas in the NAC it remained unchanged. In contrast, CREB phosphorylation in CPu and NAC increased only when the contingency changed from goal-dependent to goal-independent reinforcement ("yoked"). The present results indicate that up-regulation of CREB protein expression across cortical and striatal regions possibly reflects the extensive instrumental learning and performance whereas increased CREB activity in striatal regions may signal the unexpected change in the relationship between instrumental action and reinforcement.

Attention deficit induced by blockade of N-methyl D-aspartate receptors in the prefrontal cortex is associated with enhanced glutamate release and cAMP response element binding protein phosphorylation: role of metabotropic glutamate receptors 2/3

The hypothesis that attention deficits induced by the hypofunction of N-methyl d-aspartate (NMDA) receptors in the prefrontal cortex (PFC) might be associated with increased glutamate release and changes in the phosphorylation of the cyclic adenosine monophosphate response element-binding protein on serine 133 (p-S(133)CREB) was investigated in this study. Infusion of 50 ng/side 3-(R)-2-carboxypiperazin-4-propyl-1-phosphonic acid ((R)-CPP), a competitive glutamate NMDA receptor antagonist, into the medial prefrontal cortex (mPFC) of rats performing the five-choice serial reaction time (5-CSRT) task, reduced accuracy of visual discrimination (measured by % correct responses) and enhanced impulsivity (measured by the number of premature responses) and compulsivity (measured by the number of perseverative responses). The mGluR2/3 receptor agonist, LY379268, injected s.c. at 0.1 mg/kg, reduced (R)-CPP-induced impairment in attentional functioning (accuracy) and impulsivity but not compulsive perseveration. In parallel studies using microdialysis technique and Western blot analysis we found that (R)-CPP (100 μM) infused in the medial prefrontal cortex increased glutamate efflux whereas injected in the medial prefrontal cortex at a dose causing impairments in attentional performance (50 ng/side) increased p-S(133)CREB in the frontal cortex (FC), decreased it in the caudate-putamen (CPu) and was without effect in the nucleus accumbens (NAC). LY379268 at the dose effective in reducing (R)-CPP-induced behavioral deficit reduced both the (R)-CPP-induced rise in glutamate efflux in the prefrontal cortex and the increase in p-S(133)CREB in the frontal cortex but was without effect on the decrease in p-S(133)CREB in the caudate-putamen. The data provide evidence that enhanced glutamate release and phosphorylation of cAMP response element binding protein (CREB) on serine 133 may be associated to attention deficit and loss of impulse control. Furthermore they suggest that mGluR2/3 agonists have a therapeutic potential for cognitive deficits.

Blockade of serotonin 2A receptors prevents PCP-induced attentional performance deficit and CREB phosphorylation in the dorsal striatum of DBA/2 mice

RATIONAL AND OBJECTIVE

Functional opposition between N-methyl-D-aspartate and 5-HT(2A) receptors may be a neural mechanism supporting cognitive functions. These systems converge on an intracellular signaling pathway that involves protein kinase A-dependent phosphorylation of different proteins including cyclic adenosine monophosphate response element binding (CREB). Thus, we tested whether selective 5-HT(2A) receptor antagonist, M100907, might abolish phencyclidine (PCP)-induced attentional performance deficit by preventing its effects on transduction mechanisms leading to CREB phosphorylation.

METHODS

Using the five-choice serial reaction time task, the ability of subcutaneous injections of 2.5 and 10 microg/kg of M100907 to abolish the effects of an intraperitoneal injection of 1.5 mg/kg PCP on attentional performance as measured by accuracy (percentage of correct responses) and anticipatory and perseverative responding was assessed in DBA/2 mice. The effects of PCP, M100907, and their combination on S(133)-CREB and T(34)-DARPP32 phosphorylation in the dorsal striatum and prefrontal cortex (PFC) of behaviorally naïve mice were examined using Western blotting technique.

RESULTS

PCP reduced accuracy and increased anticipatory and perseverative responses as well as it increased S(133)-CREB phosphorylation in the dorsal striatum but not in the PFC. Ten microg/kg M100907 abolished the PCP-induced attentional performance deficits and the increase in S(133)-CREB but not T(34)-DARPP32 phosphorylation. By itself, M100907 had no effect on attentional performance or phospho-S(133)-CREB and phospho-T(34)-DARPP32. Interestingly, the effect of PCP on phospho-S(133)-CREB but not on phospho-T(34)-DARPP32 was dependent on endogenous 5-HT.

CONCLUSIONS

The data indicate that blockade of 5-HT(2A) receptors may exert beneficial effects on cognitive deficits through a mechanism linked to striatal S(133)-CREB phosphorylation.

Cannabinoid action depends on phosphorylation of dopamine- and cAMP-regulated phosphoprotein of 32 kDa at the protein kinase A site in striatal projection neurons

Herbal cannabis, smoked in the form of marihuana or hashish, is the most common illicit drug consumed in the Western world. In the brain, cannabinoids interact with neuronal CB1 receptors, thereby producing a marked reduction of motor activity. Here, we report that the motor depressant effect produced by the cannabinoid receptor agonist (-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]trans-4-(3-hydroxypropyl)cyclohexanol (CP55,940) is attenuated by genetic inactivation of the dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32), which is abundantly expressed in the medium spiny neurons of the striatum. Point mutation of Thr34, the protein kinase A (PKA) phosphorylation site of DARPP-32, produces a similar reduction in the effect of the CB1 agonist. In contrast, point mutation of Thr75, a site on DARPP-32 specifically phosphorylated by cyclin-dependent kinase 5, does not affect the behavioral response to CP55,940. Activation of CB1 receptors, either by an agonist or by inhibition of reuptake of endogenous cannabinoids, stimulates phosphorylation at Thr34, thereby converting DARPP-32 into an inhibitor of protein phosphatase-1. Genetic inactivation either of dopamine D2 receptors or of adenosine A2A receptors reduces the phosphorylation of DARPP-32 at Thr34 and the motor depression produced by CP55,940. Our data indicate that a considerable proportion of the psychomotor effect of cannabinoids can be accounted for by a signaling cascade in striatal projection neurons involving PKA-dependent phosphorylation of DARPP-32, achieved via modulation of dopamine D2 and adenosine A2A transmission.

Modular usage of the HLA-DRA promoter in extra-hematopoietic and hematopoietic cell types of transgenic mice

Class II MHC genes (for example, the human HLA-DRA gene) are expressed at the cell surface in many professional and nonprofessional antigen-presenting cells in a variety of anatomical locations. Here, we report about 13 mouse transgenic lines (11 of which have not been previously described) generated with four distinct sets of DRA transgenes carrying progressive, informative 5' and 3' deletions. DRA expression was assessed in B lymphocytes, dendritic cells, macrophages, and extra-hematopoietic cells (particularly kidney epithelial cells). A compact transcriptional unit was identified that efficiently directs DRA expression [both constitutive and interferon (IFN)-gamma induced] in extra-hematopoietic tissues and dendritic cells. It extends from position -266 upstream of the transcription initiation site to position +119 downstream of the last DRA exon. The same fragment, however, did not efficiently direct IFN-gamma-induced DRA expression in macrophages, that required additional 5' sequences. Thus, IFN-gamma uses distinct promoter segments and mechanisms to up-regulate class II in different cell lineages. In contrast to previous results in transgenic mice expressing murine class II transgenes, we were unable to generate reproducible patterns of HLA-DRA expression in B cells.

DARPP-32 and modulation of cAMP signaling: involvement in motor control and levodopa-induced dyskinesia

The dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32) is abundantly expressed in the medium spiny neurons of the striatum. Phosphorylation catalysed by cAMP-dependent protein kinase (PKA) converts DARPP-32 into an inhibitor of protein phosphatase-1. In contrast, phosphorylation catalysed by cyclin dependent kinase-5 on Thr75 converts DARPP-32 into an inhibitor of PKA. Changes in the state of phosphorylation of DARPP-32 reinforce the behavioral effects produced by stimulation or inhibition of the cAMP pathway. Dopamine, via D(1) receptors, and adenosine, via A(2A) receptors, affect motor behavior by acting on medium spiny neurons, via G(olf) mediated stimulation of the cAMP signaling cascade. The involvement of DARPP-32 in dopamine and adenosine transmission and the possible role played by abnormal regulation of DARPP-32 phosphorylation in levodopa-induced dyskinesia are discussed.

Regulation of striatal tyrosine hydroxylase phosphorylation by acute and chronic haloperidol

The typical neuroleptic haloperidol increases the state of phosphorylation and activity of tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of catecholamines. Here we show that the increases in TH phosphorylation produced by haloperidol at Ser31 and Ser40, two sites critically involved in the regulation of enzymatic activity, are abolished in dopamine D2 receptor-null mice and mimicked by the selective dopamine D2 receptor antagonist, eticlopride. Moreover, the ability of haloperidol and eticlopride to stimulate phosphorylation at both seryl residues is prevented by treatment with SL327, a compound that blocks activation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2). We also show that chronic administration of haloperidol reduces the basal levels of phosphoSer31-TH and decreases the ability of the drug to stimulate Ser40 phosphorylation. These results provide a model accounting for the stimulation exerted by haloperidol on dopamine synthesis. According to this model, haloperidol increases TH activity via blockade of dopamine D2 receptors, disinhibition of dopaminergic projection neurons and ERK1/2-dependent phosphorylation of TH at Ser31 and Ser40. These studies also show that lower levels of phosphorylated TH are associated with chronic neuroleptic treatment and may be related to depressed dopaminergic transmission in nigrostriatal neurons.

Opposite regulation by typical and atypical anti-psychotics of ERK1/2, CREB and Elk-1 phosphorylation in mouse dorsal striatum

The two mitogen-activated protein kinases (MAPKs), extracellular signal-regulated protein kinase 1 and 2 (ERK1/2), are involved in the control of gene expression via phosphorylation and activation of the transcription factors cyclic AMP response element binding protein (CREB) and Elk-1. Here, we have examined the effect of haloperidol and clozapine, two anti-psychotic drugs, and eticlopride, a selective dopamine D2 receptor antagonist, on the state of phosphorylation of ERK1/2, CREB and Elk-1, in the mouse dorsal striatum. Administration of the typical anti-psychotic haloperidol stimulated the phosphorylation of ERK1/2, CREB and Elk-1. Virtually identical results were obtained using eticlopride. In contrast, the atypical anti-psychotic clozapine reduced ERK1/2, CREB and Elk-1 phosphorylation. This opposite regulation was specifically exerted by haloperidol and clozapine on ERK, CREB, and Elk-1 phosphorylation, as both anti-psychotic drugs increased the phosphorylation of the dopamine- and cyclic AMP-regulated phosphoprotein of 32 kDa (DARPP-32) at the cyclic AMP-dependent protein kinase (PKA) site. The activation of CREB and Elk-1 induced by haloperidol appeared to be achieved via different signalling pathways, as inhibition of ERK1/2 activation abolished the stimulation of Elk-1 phosphorylation without affecting CREB phosphorylation. This study shows that haloperidol and clozapine induce distinct patterns of phosphorylation in the dorsal striatum. The results provide a novel biochemical paradigm elucidating the molecular mechanisms underlying the distinct therapeutic actions of typical and atypical anti-psychotic agents.

Deletion of the mental retardation gene Gdi1 impairs associative memory and alters social behavior in mice

Non-specific mental retardation (NSMR) is a common human disorder characterized by mental handicap as the only clinical symptom. Among the recently identified MR genes is GDI1, which encodes alpha Gdi, one of the proteins controlling the activity of the small GTPases of the Rab family in vesicle fusion and intracellular trafficking. We report the cognitive and behavioral characterization of mice carrying a deletion of Gdi1. The Gdi1-deficient mice are fertile and anatomically normal. They appear normal also in many tasks to assess spatial and episodic memory and emotional behavior. Gdi1-deficient mice are impaired in tasks requiring formation of short-term temporal associations, suggesting a defect in short-term memory. In addition, they show lowered aggression and altered social behavior. In mice, as in humans, lack of Gdi1 spares most central nervous system functions and preferentially impairs only a few forebrain functions required to form temporal associations. The general similarity to human mental retardation is striking, and suggests that the Gdi1 mutants may provide insights into the human defect and into the molecular mechanisms important for development of cognitive functions.

Involvement of DARPP-32 phosphorylation in the stimulant action of caffeine

Caffeine has been imbibed since ancient times in tea and coffee, and more recently in colas. Caffeine owes its psychostimulant action to a blockade of adenosine A(2A) receptors, but little is known about its intracellular mechanism of action. Here we show that the stimulatory effect of caffeine on motor activity in mice was greatly reduced following genetic deletion of DARPP-32 (dopamine- and cyclic AMP-regulated phosphoprotein of relative molecular mass 32,000). Results virtually identical to those seen with caffeine were obtained with the selective A(2A) antagonist SCH 58261. The depressant effect of the A(2A) receptor agonist, CGS 21680, on motor activity was also greatly attenuated in DARPP-32 knockout mice. In support of a role for DARPP-32 in the action of caffeine, we found that, in striata of intact mice, caffeine increased the state of phosphorylation of DARPP-32 at Thr 75. Caffeine increased Thr 75 phosphorylation through inhibition of PP-2A-catalysed dephosphorylation, rather than through stimulation of cyclin-dependent kinase 5 (Cdk5)-catalysed phosphorylation, of this residue. Together, these studies demonstrate the involvement of DARPP-32 and its phosphorylation/dephosphorylation in the stimulant action of caffeine.

Transient post-traumatic hemidiaphragmatic paralysis in two cats

A diagnosis of post-traumatic hemidiaphragmatic paralysis was made in two cats. Both cats had a history of trauma and paradoxical inward movement of the abdominal wall at inspiration. Thoracic radiographs were taken at inspiration and expiration. Although the images were suggestive of hemidiaphragmatic paralysis, definitive diagnosis was reached by fluoroscopy in one cat and by ultrasonography in the second. Both cases resolved spontaneously and diaphragmatic function was normal at follow-up.

Stimulation of 5-hydroxytryptamine (5-HT(2C) ) receptors in the ventrotegmental area inhibits stress-induced but not basal dopamine release in the rat prefrontal cortex

The present study investigated whether 5-HT(2C) receptors in the ventrotegmental area and prefrontal cortex regulate basal and stimulus-evoked dopamine release in the prefrontal cortex. Using the in vivo microdialysis technique in conscious rats, we studied the effect of a selective 5-HT(2C) receptor agonist, Ro60-0175, on basal and immobilization stress-induced dopamine release in the prefrontal cortex. Ro60-0175 intraperitoneally (2.5 mg/kg) and into the ventrotegmental area (10 microg/0.5 microL) completely antagonized the effect of stress on extracellular dopamine without altering basal levels. Infusion of 10 microm Ro60-0175 through the cortical probe had no significant effect on basal and stress-induced dopamine release. SB242084 (10 mg/kg), a selective antagonist of 5-HT(2C) receptors, significantly increased basal extracellular dopamine and completely prevented the effect of intraperitoneal and intraventrotegmental Ro60-0175 on the stress-induced rise of extracellular dopamine, but had no effect itself in stressed rats. The results show that Ro60-0175 suppresses cortical dopamine release induced by immobilization stress through the stimulation of 5-HT(2C) receptors in the ventrotegmental area. While confirming that endogenous 5-HT acting on 5-HT(2C) receptors tonically inhibit basal dopamine release in the prefrontal cortex, the present findings suggest that the stimulation of 5-HT(2C) receptors with an exogenous agonist preferentially inhibit stimulated release.