Phenotypic spectrum of myelin protein zero-related neuropathies: a large cohort study from five mutation clusters across Italy.

BACKGROUND: We aimed to investigate the clinical features of a large cohort of patients with myelin protein zero (MPZ)-related neuropathy, focusing on the five main mutation clusters across Italy. METHODS: We retrospectively gathered a minimal data set of clinical information in a series of patients with these frequent mutations recruited among Italian Charcot-Marie-Tooth (CMT) registry centres, including disease onset/severity (CMTES-CMT Examination Score), motor/sensory symptoms and use of orthotics/aids. RESULTS: We collected data from 186 patients: 60 had the p.Ser78Leu variant ('classical' CMT1B; from Eastern Sicily), 42 the p.Pro70Ser (CMT2I; mainly from Lombardy), 38 the p.Thr124Met (CMT2J; from Veneto), 25 the p.Ser44Phe (CMT2I; from Sardinia) and 21 the p.Asp104ThrfsX13 (mild CMT1B; from Apulia) mutation. Disease severity (CMTES) was higher (p<0.001) in late-onset axonal forms (p.Thr124Met=9.2±6.6; p.Ser44Phe=7.8±5.7; p.Pro70Ser=7.6±4.8) compared with p.Ser78Leu (6.1±3.5) patients. Disease progression (ΔCMTES/year) was faster in the p.Pro70Ser cohort (0.8±1.0), followed by p.Ser44Phe (0.7±0.4), p.Thr124Met (0.4±0.5) and p.Ser78Leu (0.2±0.4) patients. Disease severity (CMTES=1.2±1.5), progression (ΔCMTES/year=0.1±0.4) and motor involvement were almost negligible in p.Asp104ThrfsX13 patients, who, however, frequently (78%, p<0.001) complained of neuropathic pain. In the other four clusters, walking difficulties were reported by 69-85% of patients, while orthotic and walking aids use ranged between 40-62% and 16-28%, respectively. CONCLUSIONS: This is the largest MPZ (and late-onset CMT2) cohort ever collected, reporting clinical features and disease progression of 186 patients from five different clusters across Italy. Our findings corroborate the importance of differentiating between 'classical' childhood-onset demyelinating, late-onset axonal and mild MPZ-related neuropathy, characterised by different pathomechanisms, in view of different therapeutic targets.

An empowered, clinically viable hematopoietic stem cell gene therapy for the treatment of multisystemic mucopolysaccharidosis type II.

Mucopolysaccharidosis type II (MPS II), or Hunter syndrome, is a rare X-linked recessive lysosomal storage disorder due to a mutation in the lysosomal enzyme iduronate-2-sulfatase (IDS) gene. IDS deficiency leads to a progressive, multisystem accumulation of glycosaminoglycans (GAGs) and results in central nervous system (CNS) manifestations in the severe form. We developed up to clinical readiness a new hematopoietic stem cell (HSC) gene therapy approach for MPS II that benefits from a novel highly effective transduction protocol. We first provided proof of concept of efficacy of our approach aimed at enhanced IDS enzyme delivery to the CNS in a murine study of immediate translational value, employing a lentiviral vector (LV) encoding a codon-optimized human IDS cDNA. Then the therapeutic LV was tested for its ability to efficiently and safely transduce bona fide human HSCs in clinically relevant conditions according to a standard vs. a novel protocol that demonstrated superior ability to transduce bona fide long-term repopulating HSCs. Overall, these results provide strong proof of concept for the clinical translation of this approach for the treatment of Hunter syndrome.

Use, tolerability, benefits and side effects of orthotic devices in Charcot-Marie-Tooth disease.

BACKGROUND: Shoe inserts, orthopaedic shoes, ankle-foot orthoses (AFOs) are important devices in Charcot-Marie-Tooth disease (CMT) management, but data about use, benefits and tolerance are scanty. METHODS: We administered to Italian CMT Registry patients an online ad hoc questionnaire investigating use, complications and perceived benefit/tolerability/emotional distress of shoe inserts, orthopaedic shoes, AFOs and other orthoses/aids. Patients were also asked to fill in the Quebec User Evaluation of Satisfaction with assistive Technology questionnaire, rating satisfaction with currently used AFO and related services. RESULTS: We analysed answers from 266 CMT patients. Seventy per cent of subjects were prescribed lower limb orthoses, but 19% did not used them. Overall, 39% of subjects wore shoe inserts, 18% orthopaedic shoes and 23% AFOs. Frequency of abandonment was high: 24% for shoe inserts, 28% for orthopaedic shoes and 31% for AFOs. Complications were reported by 59% of patients and were more frequently related to AFOs (69%). AFO users experienced greater emotional distress and reduced tolerability as compared with shoe inserts (p<0.001) and orthopaedic shoes (p=0.003 and p=0.045, respectively). Disease severity, degree of foot weakness, customisation and timing for customisation were determinant factors in AFOs' tolerability. Quality of professional and follow-up services were perceived issues. CONCLUSIONS: The majority of CMT patients is prescribed shoe inserts, orthopaedic shoes and/or AFOs. Although perceived benefits and tolerability are rather good, there is a high rate of complications, potentially inappropriate prescriptions and considerable emotional distress, which reduce the use of AFOs. A rational, patient-oriented and multidisciplinary approach to orthoses prescription must be encouraged.

Daytime sleepiness and sleep quality in Charcot-Marie-Tooth disease.

BACKGROUND: Sleep abnormalities have been reported in Charcot-Marie-Tooth disease (CMT), but data are scanty. We investigated their presence and correlation in a large CMT patients' series. METHODS: Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI) were administered to CMT patients of the Italian registry and controls. ESS score > 10 indicated abnormal daytime somnolence, PSQI score > 5 bad sleep quality. We analyzed correlation with disease severity and characteristics, Hospital Anxiety and Depression Scale (HADS), Modified Fatigue Impact Scale (MFIS), Body Mass Index, drug use. RESULTS: ESS and PSQI questionnaires were filled by 257 and 253 CMT patients, respectively, and 58 controls. Median PSQI score was higher in CMT patients than controls (6 vs 4, p = 0.006), with no difference for ESS score. Abnormal somnolence and poor sleep quality occurred in 23% and 56% of patients; such patients had more frequently anxiety/depression, abnormal fatigue, and positive sensory symptoms than those with normal ESS/PSQI. Moreover, patients with PSQI score > 5 had more severe disease (median CMT Examination Score, CMTES, 8 vs 6, p = 0.006) and more frequent use of anxiolytic/antidepressant drugs (29% vs 7%, p < 0.001). CONCLUSIONS: Bad sleep quality and daytime sleepiness are frequent in CMT and correlated with anxiety, depression and fatigue, confirming that different components affect sleep. Sleep disorders, such as sleep apnea and restless leg syndrome, not specifically investigated here, are other factors known to impact on sleep quality and somnolence. CMT patients' management must include sleep behavior assessment and evaluation of its correlated factors, including general distress and fatigue.

An innovative hematopoietic stem cell gene therapy approach benefits CLN1 disease in the mouse model.

Hematopoietic stem and progenitor cells (HSPCs) can establish a long-lasting microglia-like progeny in the central nervous system of properly myeloablated hosts. We exploited this approach to treat the severe CLN1 neurodegenerative disorder, which is the most aggressive form of neuronal ceroid lipofuscinoses due to palmitoyl-protein thioesterase-1 (PPT1) deficiency. We here provide the first evidence that (i) transplantation of wild-type HSPCs exerts partial but long-lasting mitigation of CLN1 symptoms; (ii) transplantation of HSPCs over-expressing hPPT1 by lentiviral gene transfer enhances the therapeutic benefit of HSPCs transplant, with first demonstration of such a dose-effect benefit for a purely neurodegenerative condition like CLN1 disease; (iii) transplantation of hPPT1 over-expressing HSPCs by a novel intracerebroventricular (ICV) approach is sufficient to transiently ameliorate CLN1-symptoms in the absence of hematopoietic tissue engraftment of the transduced cells; and (iv) combinatorial transplantation of transduced HSPCs intravenously and ICV results in a robust therapeutic benefit, particularly on symptomatic animals. Overall, these findings provide first evidence of efficacy and feasibility of this novel approach to treat CLN1 disease and possibly other neurodegenerative conditions, paving the way for its future clinical application.

Identification of a retinoic acid-dependent haemogenic endothelial progenitor from human pluripotent stem cells.

The generation of haematopoietic stem cells (HSCs) from human pluripotent stem cells (hPSCs) is a major goal for regenerative medicine. During embryonic development, HSCs derive from haemogenic endothelium (HE) in a NOTCH- and retinoic acid (RA)-dependent manner. Although a WNT-dependent (WNTd) patterning of nascent hPSC mesoderm specifies clonally multipotent intra-embryonic-like HOXA+ definitive HE, this HE is functionally unresponsive to RA. Here we show that WNTd mesoderm, before HE specification, is actually composed of two distinct KDR+ CD34neg populations. CXCR4negCYP26A1+ mesoderm gives rise to HOXA+ multilineage definitive HE in an RA-independent manner, whereas CXCR4+ ALDH1A2+ mesoderm gives rise to HOXA+ multilineage definitive HE in a stage-specific, RA-dependent manner. Furthermore, both RA-independent (RAi) and RA-dependent (RAd) HE harbour transcriptional similarity to distinct populations found in the early human embryo, including HSC-competent HE. This revised model of human haematopoietic development provides essential resolution to the regulation and origins of the multiple waves of haematopoiesis. These insights provide the basis for the generation of specific haematopoietic populations, including the de novo specification of HSCs.

Metallothioneins are neuroprotective agents in lysosomal storage disorders.

OBJECTIVE: Lysosomal storage disorders (LSDs) are a broad class of inherited metabolic diseases caused by the defective activity of lysosomal enzymes. Central nervous system (CNS) manifestations are present in roughly 50% of LSD patients and represent an unmet medical need for them. We explored the therapeutic potential of metallothioneins (MTs), a newly identified family of proteins with reported neuroprotective roles, in the murine models of two LSDs with CNS involvement. METHODS: MT-1 overexpressing transgenic mice (MTtg) were crossed with the murine models of Batten and Krabbe diseases. Changes in the survival and manifestations of the disease in the MTtg setting were assessed. In addition, we analyzed the therapeutic effects of MT-1 CNS gene delivery in one of these LSD models. RESULTS: Constitutive expression of MT-1 exerted favorable phenotypic effects in both LSD models. MT-LSD mice showed a 5% to 10% increase in survival and slower disease progression as compared to not-transgenic LSD mice. Rescue of Purkinje cells from degeneration and apoptosis was also observed in the MT-LSD models. This phenotypic amelioration was accompanied by a modulation of the disease-associated activated inflammatory microglia phenotype, and by a reduction of oxidative stress. Importantly, for the clinical translation of our findings, the very same effects were obtained when MTs were delivered to brains by systemic AAV gene transfer. INTERPRETATION: MTs can be considered novel therapeutic agents (and targets) in LSDs and potentiate the effects of approaches aiming at correction of the disease-causing enzyme deficiency in the CNS. Ann Neurol 2018;83:418-432 Ann Neurol 2018;83:418-432.

Intracerebroventricular delivery of hematopoietic progenitors results in rapid and robust engraftment of microglia-like cells.

Recent evidence indicates that hematopoietic stem and progenitor cells (HSPCs) can serve as vehicles for therapeutic molecular delivery to the brain by contributing to the turnover of resident myeloid cell populations. However, such engraftment needs to be fast and efficient to exert its therapeutic potential for diseases affecting the central nervous system. Moreover, the nature of the cells reconstituted after transplantation and whether they could comprise bona fide microglia remain to be assessed. We demonstrate that transplantation of HSPCs in the cerebral lateral ventricles provides rapid engraftment of morphologically, antigenically, and transcriptionally dependable microglia-like cells. We show that the cells comprised within the hematopoietic stem cell compartment and enriched early progenitor fractions generate this microglia-like population when injected in the brain ventricles in the absence of engraftment in the bone marrow. This delivery route has therapeutic relevance because it increases the delivery of therapeutic molecules to the brain, as shown in a humanized animal model of a prototypical lysosomal storage disease affecting the central nervous system.

Metallothioneins as dynamic markers for brain disease in lysosomal disorders.

OBJECTIVE: To facilitate development of novel disease-modifying therapies for lysosomal storage disorder (LSDs) characterized by nervous system involvement such as metachromatic leukodystrophy (MLD), molecular markers for monitoring disease progression and therapeutic response are needed. To this end, we sought to identify blood transcripts associated with the progression of MLD. METHODS: Genome-wide expression analysis was performed in primary T lymphocytes of 24 patients with MLD compared to 24 age- and sex-matched healthy controls. Genes associated with MLD were identified, confirmed on a quantitative polymerase chain reaction platform, and replicated in an independent patient cohort. mRNA and protein expression of the prioritized gene family of metallothioneins was evaluated in postmortem patient brains and in mouse models representing 6 other LSDs. Metallothionein expression during disease progression and in response to specific treatment was evaluated in 1 of the tested LSD mouse models. Finally, a set of in vitro studies was planned to dissect the biological functions exerted by this class of molecules. RESULTS: Metallothionein genes were significantly overexpressed in T lymphocytes and brain of patients with MLD and generally marked nervous tissue damage in the LSDs here evaluated. Overexpression of metallothioneins correlated with measures of disease progression in mice and patients, whereas their levels decreased in mice upon therapeutic treatment. In vitro studies indicated that metallothionein expression is regulated in response to oxidative stress and inflammation, which are biochemical hallmarks of lysosomal storage diseases. INTERPRETATION: Metallothioneins are potential markers of neurologic disease processes and treatment response in LSDs.

A preliminary experimental investigation of peer influence on risk-taking among adolescent smokers and non-smokers.

BACKGROUND: Epidemiological evidence suggests that peer influence plays a significant role in a variety of adolescent risk-taking behaviors, including tobacco use. We attempted to establish this relationship in a controlled laboratory setting. METHOD: We modified the Balloon Analog Risk Task (BART) task to include a peer component to investigate whether peer influences alter risk-taking behaviors. Thirty-nine adolescents (22 smokers, 17 non-smokers) completed one experimental session during which the standard and peer BART were presented in counterbalanced order, with the dependent measures being adjusted mean number of pumps and explosions. We also examined the relationship of changes in the BART (standard-peer) to personality measures of impulsivity (BIS-11) and resistance to peer influence (RPI). RESULTS: A significant interaction of BART type and smoking status was present (p=.05); specifically smokers had a greater increase in the number of explosions by 2.27 (SD=3.12) compared to an increase of .29 (SD=2.87) by non-smokers. BIS-11 scores were related to peer-influenced BART changes: those who were more impulsive experienced greater changes in risk-taking, but no similar relationships were observed for the RPI. CONCLUSIONS: These results suggest that peer influences enhance risk-taking among adolescents, and that smokers may be more susceptible to these influences.

A recent class of chemosensory neurons developed in mouse and rat.

In most animal species, the vomeronasal organ ensures the individual recognition of conspecifics, a prerequisite for a successful reproduction. The vomeronasal organ expresses several receptors for pheromone detection. Mouse vomeronasal type-2 receptors (V2Rs) are restricted to the basal neurons of this organ and organized in four families. Family-A, B and D (family ABD) V2Rs are expressed monogenically (one receptor per neuron) and coexpress with either Vmn2r1 or Vmn2r2, two members of family-C V2Rs. Thus, basal neurons are characterized by specific combinations of two V2Rs. To investigate this issue, we raised antibodies against all family-C V2Rs and analyzed their expression pattern. We found that six out of seven family-C V2Rs (Vmn2r2-7) largely coexpressed and that none of the anti-Vmn2r2-7 antibodies significantly stained Vmn2r1 positive neurons. Thus, basal neurons are divided into two complementary subsets. The first subset (Vmn2r1-positive) preferentially coexpresses a distinct group of family-ABD V2Rs, whereas the second subset (Vmn2r2-7-positive) coexpresses the remaining group of V2Rs. Phylogenetic reconstruction and the analysis of genetic loci in various species reveal that receptors expressed by this second neuronal subset are recent branches of the V2R tree exclusively present in mouse and rat. Conversely, V2Rs expressed in Vmn2r1 positive neurons, are phylogenetically ancient and found in most vertebrates including rodents. Noticeably, the more recent neuronal subset expresses a type of Major Histocompatibility Complex genes only found in murine species. These results indicate that the expansion of the V2R repertoire in a murine ancestor occurred with the establishment of a new population of vomeronasal neurons in which coexists the polygenic expression of a recent group of family-C V2Rs (Vmn2r2-7) and the monogenic expression of a recent group of family-ABD V2Rs. This evolutionary innovation could provide a molecular rationale for the exquisite ability in individual recognition and mate choice of murine species.