Faculty Bibliography

Spinal muscular atrophy with respiratory distress type 1 (SMARD1), also known as distal spinal-muscular atrophy 1 (DSMA10), is an autosomal recessive type of spinal muscular atrophy that is related to mutations in the IGHMBP2 gene, which encodes for the immunoglobulin μ-binding protein. SMARD1 patients usually present low birth weight, diaphragmatic palsy and distal muscular atrophy. Clinical features are still the most important factor that leads to the diagnosis of SMARD1, due to the fact that IGHMBP2 gene mutations are characterized by significant phenotypic heterogeneity. In the present review, we will systematically discuss the genetic, clinical and neuropathological features of SMARD1 in order to provide a complete overview of SMARD1 variable clinical presentations and of the most important diagnostic tools which can be used to identify and properly manage affected individuals. This background is crucial also in the perspective of the development of novel therapeutic strategies for this still orphan disorder.

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease characterized by degeneration of upper and lower motor neurons. There are currently no clinically impactful treatments for this disorder. Death occurs 3-5 years after diagnosis, usually due to respiratory failure. ALS pathogenesis seems to involve several pathological mechanisms (i.e., oxidative stress, inflammation, and loss of the glial neurotrophic support, glutamate toxicity) with different contributions from environmental and genetic factors. This multifaceted combination highlights the concept that an effective therapeutic approach should counteract simultaneously different aspects: stem cell therapies are able to maintain or rescue motor neuron function and modulate toxicity in the central nervous system (CNS) at the same time, eventually representing the most comprehensive therapeutic approach for ALS. To achieve an effective cell-mediated therapy suitable for clinical applications, several issues must be addressed, including the identification of the most performing cell source, a feasible administration protocol, and the definition of therapeutic mechanisms. The method of cell delivery represents a major issue in developing cell-mediated approaches since the cells, to be effective, need to be spread across the CNS, targeting both lower and upper motor neurons. On the other hand, there is the need to define a strategy that could provide a whole distribution without being too invasive or burdened by side effects. Here, we review the recent advances regarding the therapeutic potential of stem cells for ALS with a focus on the minimally invasive strategies that could facilitate an extensive translation to their clinical application.

Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a motor neuron disease caused by mutations in the IGHMBP2 gene, without a cure. Here, we demonstrate that neural stem cells (NSCs) from human-induced pluripotent stem cells (iPSCs) have therapeutic potential in the context of SMARD1. We show that upon transplantation NSCs can appropriately engraft and differentiate in the spinal cord of SMARD1 animals, ameliorating their phenotype, by protecting their endogenous motor neurons. To evaluate the effect of NSCs in the context of human disease, we generated human SMARD1-iPSCs motor neurons that had a significantly reduced survival and axon length. Notably, the coculture with NSCs ameliorate these disease features, an effect attributable to the production of neurotrophic factors and their dual inhibition of GSK-3 and HGK kinases. Our data support the role of iPSC as SMARD1 disease model and their translational potential for therapies in motor neuron disorders.

Neurodegenerative disorders are characterized by the selective vulnerability and progressive loss of discrete neuronal populations. Non-neuronal cells appear to significantly contribute to neuronal loss in diseases such as amyotrophic lateral sclerosis (ALS), Parkinson, and Alzheimer's disease. In ALS, there is deterioration of motor neurons in the cortex, brainstem, and spinal cord, which control voluntary muscle groups. This results in muscle wasting, paralysis, and death. Neuroinflammation, characterized by the appearance of reactive astrocytes and microglia as well as macrophage and T-lymphocyte infiltration, appears to be highly involved in the disease pathogenesis, highlighting the involvement of non-neuronal cells in neurodegeneration. There appears to be cross-talk between motor neurons, astrocytes, and immune cells, including microglia and T-lymphocytes, which are subsequently activated. Currently, effective therapies for ALS are lacking; however, the non-cell autonomous nature of ALS may indicate potential therapeutic targets. Here, we review the mechanisms of action of astrocytes, microglia, and T-lymphocytes in the nervous system in health and during the pathogenesis of ALS. We also evaluate the therapeutic potential of these cellular populations, after transplantation into ALS patients and animal models of the disease, in modulating the environment surrounding motor neurons from pro-inflammatory to neuroprotective. We also thoroughly discuss the recent advances made in the field and caveats that need to be overcome for clinical translation of cell therapies aimed at modulating non-cell autonomous events to preserve remaining motor neurons in patients.

Developmental studies and experimental data have enabled us to assert that the terminal cell differentiation state is reversible, and that altering the balance of specific transcription factors could be a powerful strategy for inducing pluripotency. Due to the risks related to using induced pluripotent cells in clinical applications, biologists are now striving to develop methods to induce a committed differentiated cell type by direct conversion of another cell line. Several reprogramming factors have been discovered, and some cellular phenotypes have been obtained by novel transdifferentiation processes. It has been recently demonstrated that induced neural stem cells (iNSCs) can be obtained from rodent and human somatic cells, like fibroblasts, through the forced expression of defined transcription factors. To date, two different approaches have been successfully used to obtain iNSCs: a direct method and an indirect method that involves an intermediate destabilized state. The possibility to induce characterized iNSCs from human cells, e.g. fibroblasts, has opened new horizons for research in human disease modelling and cellular therapeutic applications in the neurological field. This review focuses on reported reprogramming techniques and innovative techniques that can be further explored in this area, as well as on the criteria for the phenotypic characterization of iNSCs and their use in developing novel therapeutic strategies for neurological diseases.

Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease. It is the first genetic cause of infant mortality. It is caused by mutations in the survival motor neuron 1 (SMN1) gene, leading to the reduction of SMN protein. The most striking component is the loss of alpha motor neurons in the ventral horn of the spinal cord, resulting in progressive paralysis and eventually premature death. There is no current treatment other than supportive care, although the past decade has seen a striking advancement in understanding of both SMA genetics and molecular mechanisms. A variety of disease modifying interventions are rapidly bridging the translational gap from the laboratory to clinical trials. In this review, we would like to outline the most interesting therapeutic strategies that are currently developing, which are represented by molecular, gene and stem cell-mediated approaches for the treatment of SMA.

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease characterized by the degeneration of motor neurons. Currently, there is no effective therapy for ALS. Stem cell transplantation is a potential therapeutic strategy for ALS, and the reprogramming of adult somatic cells into induced pluripotent stem cells (iPSCs) represents a novel cell source. In this study, we isolated a specific neural stem cell (NSC) population from human iPSCs based on high aldehyde dehydrogenase activity, low side scatter and integrin VLA4 positivity. We assessed the therapeutic effects of these NSCs on the phenotype of ALS mice after intrathecal or intravenous injections. Transplanted NSCs migrated and engrafted into the central nervous system via both routes of injection. Compared with control ALS, treated ALS mice exhibited improved neuromuscular function and motor unit pathology and significantly increased life span, in particular with the systemic administration of NSCs (15%). These positive effects are linked to multiple mechanisms, including production of neurotrophic factors and reduction of micro- and macrogliosis. NSCs induced a decrease in astrocyte number through the activation of the vanilloid receptor TRPV1. We conclude that minimally invasive injections of iPSC-derived NSCs can exert a therapeutic effect in ALS. This study contributes to advancements in iPSC-mediated approaches for treating ALS and other neurodegenerative diseases.

OBJECTIVES/OBJECTIVE:Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease mainly involving cortical and spinal motor neurones. Molecular studies have recently identified different mutations in the  ubiquilin-2 (UBQLN2) gene as causative of a familial form of X-linked ALS, 90% penetrant in women. The aim of our study was to analyse the UBQLN2 gene in a large cohort of patients with familial (FALS) and sporadic (SALS) amyotrophic lateral sclerosis, with or without frontotemporal dementia (FTD), and in patients with FTD. METHODS:We analysed the UBQLN2 gene in 819 SALS cases, 226 FALS cases, 53 ALS-FTD patients, and 63 patients with a clinical record of FTD. Molecular analysis of the entire coding sequence was carried out in all FALS and ALS-FTD patients, while SALS and FTD patients were analysed specifically for the genomic region coding for the PXX repeat tract. Healthy controls were 845 anonymous blood donors and were screened for the PXX repeat region only. RESULTS:We found five different variants in the UBQLN2 gene in five unrelated ALS patients. Three variants, including two novel ones, involved a proline residue in the PXX repeat region and were found in three FALS cases. The other two were novel variants, identified in one FALS and one SALS patient. None of these variants was present in controls, while one control carried a new heterozygous variant. CONCLUSIONS:Our data support the role of the UBQLN2 gene in the pathogenesis of FALS, being conversely a rare genetic cause in SALS even when complicated by FTD.

Carotid and vertebral artery dissection are relatively frequent and risky conditions. In the last decade, different patients with extracranial (and in 1 case also intracranial) dissections associated with the practice of scuba diving were reported. The connection between the two conditions has not been fully explained so far. In the present article, we report the case of a patient presenting with Claude Bernard-Horner syndrome and homolateral XII cranial nerve palsy, manifesting a few days after diving in the cold water of a lake. The patient ended up having internal carotid artery dissection associated with the formation of a pseudoaneurysm. Here, we offer a summary of all cases reported in the literature about scuba diving and arterial dissection, and provide a critical discussion about which scuba diving-related factors can trigger the dissection of cervical vessels.

Mitochondria are highly dynamic, complex organelles that continuously alter their shape, ranging between two opposite processes, fission and fusion, in response to several stimuli and the metabolic demands of the cell. Alterations in mitochondrial dynamics due to mutations in proteins involved in the fusion-fission machinery represent an important pathogenic mechanism of human diseases. The most relevant proteins involved in the mitochondrial fusion process are three GTPase dynamin-like proteins: mitofusin 1 (MFN1) and 2 (MFN2), located in the outer mitochondrial membrane, and optic atrophy protein 1 (OPA1), in the inner membrane. An expanding number of degenerative disorders are associated with mutations in the genes encoding MFN2 and OPA1, including Charcot-Marie-Tooth disease type 2A and autosomal dominant optic atrophy. While these disorders can still be considered rare, defective mitochondrial dynamics seem to play a significant role in the molecular and cellular pathogenesis of more common neurodegenerative diseases, for example, Alzheimer's and Parkinson's diseases. This review provides an overview of the basic molecular mechanisms involved in mitochondrial fusion and focuses on the alteration in mitochondrial DNA amount resulting from impairment of mitochondrial dynamics. We also review the literature describing the main disorders associated with the disruption of mitochondrial fusion.