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Fornai F.,University of Pisa | Fornai F.,Neurobiology of Movement Disorder Unit INM IRCCS Neuromed | Meininger V.,Center Referent Maladies Rares | Silani V.,University of Milan
Archives Italiennes de Biologie | Year: 2011

Classic concepts on amyotrophic lateral sclerosis led to define the disease as a selective degeneration of upper and lower motor neurons. At present such selectivity is questioned by novel findings. For instance, the occurrence of frontotemporal dementia is now increasingly recognized in the course of ALS. Again, areas outside the central nervous system are targeted in ALS. In keeping with motor areas other cell types surrounding motor neurons such as glia and interneurons are key in the pathogenesis of ALS. This multiple cell involvement may be due to a prion-like diffusion of specific misfolded proteins which are altered in ALS. This is the case of FUS and TDP-43 which harbor a prion domain prone to pathological misfolding. These misfolded proteins are metabolized by the autophagy, but in ALS there is evidence for a specific deficit of autophagy which impedes the clearance of these proteins. These concepts lead to re-analyze the potential therapeutics of ALS. In fact, mere cell substitution (stem cell) therapy appears insufficient to contrast all the alterations in the various pathways affected by ALS. Although preclinical data speed the application of stem cells in human clinical trials, several hurdles limit their translation into new therapies. Future treatments are expected to consider the need to target both motor neurons and neighboring cells which may contribute to the diffusion and persistence of the disease. On this basis the present manuscript describes which future strategies need to be pursued in order to design optimal therapeutic trial in ALS.

Ferrucci M.,University of Pisa | Fulceri F.,University of Pisa | Toti L.,University of Pisa | Soldani P.,University of Pisa | And 4 more authors.
Archives Italiennes de Biologie | Year: 2011

In the present review a large amount of experimental and clinical studies on ALS are discussed in an effort to dissect common pathogenic mechanisms which may provide novel information and potential therapeutic strategies for motor neuron degeneration. Protein clearing systems play a critical role in motor neuron survival during excitotoxic stress, aging and neurodegenerative disorders. Among various mechanisms which clear proteins from the cell recent studies indicate autophagy as the most prominent pathway to promote survival of motor neurons. Autophagy regulates the clearance of damaged mitochondria, endoplasmic reticulum and misfolded proteins in eukaryotic cells. Upon recruitment of the autophagy pathway, an autophagosome is produced and directed towards lysosomal degradation. Here we provide evidence that in both genetic and sporadic amyotrophic lateral sclerosis (ALS, the most common motor neuron disorder) a defect in the autophagy machinery is common. In fact, swollen, disrupted mitochondria and intracellular protein aggregates accumulate within affected motor neurons. These structures localize within double membrane vacuoles, autophagosomes, which typically cluster in perinuclear position. In keeping with this, when using autophagy inhibitors or suppressing autophagy promoting genes, motor symptoms and motor neuron death are accelerated. Conversely stimulation of autophagy alleviates motor neuron degeneration. Therefore, autophagy represents an important target when developing novel treatments in ALS.

Fulceri F.,University of Pisa | Ferrucci M.,University of Pisa | Lazzeri G.,University of Pisa | Paparelli S.,University of Pisa | And 5 more authors.
Archives Italiennes de Biologie | Year: 2011

Recent literature demonstrated that exposure to excitatory amino acid in specific experimental conditions might produce a defect in the autophagy pathway. Such an effect was observed in motor neurons exposed chronically to glutamate agonists. On the other hand, it is well known that glutamate induces motor neuron death and this is supposed to play a key role in the physiopathology of motor neuron loss in amyotrophic lateral sclerosis (ALS). Similarly, a defective recruitment of autophagy was recently documented in ALS. In the present study we found that exposure of motor neurons to kainic acid produces intracellular changes associated with defective autophagy. In this experimental conditions, pharmacological activation of autophagy rescues the loss of motor neurons.

Carlesi C.,University of Pisa | Pasquali L.,University of Pisa | Piazza S.,University of Pisa | Lo Gerfo A.,University of Pisa | And 5 more authors.
Archives Italiennes de Biologie | Year: 2011

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and ultimately fatal neurodegenerative disorder of unknown aetiology that involves the loss of upper and lower motor neurons in the cerebral cortex, brainstem and spinal cord. Significant progress in understanding the cellular mechanisms of motor neuron degeneration in ALS has not been matched with the development of therapeutic strategies to prevent disease progression, and riluzole remains the only available therapy, with only marginal effects on disease survival. More recently alterations of mRNA processing in genetically defined forms of ALS, as those related to TDP-43 and FUS-TLS gene mutations have provided important insights into the molecular networks implicated in the disease pathogenesis. Here we review some of the recent progress in promoting therapeutic strategies for neurodegeneration.

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