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Fulceri F, Biagioni F, Limanaqi F, Busceti CL, Ryskalin L, Lenzi P, Fornai F. Ultrastructural characterization of peripheral denervation in a mouse model of Type III spinal muscular atrophy. J Neural Transm (Vienna) 2021; 128:771-791. [PMID: 33999256 PMCID: PMC8205903 DOI: 10.1007/s00702-021-02353-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/10/2021] [Indexed: 01/02/2023]
Abstract
Spinal muscular atrophy (SMA) is a heritable, autosomal recessive neuromuscular disorder characterized by a loss of the survival of motor neurons (SMN) protein, which leads to degeneration of lower motor neurons, and muscle atrophy. Despite SMA being nosographically classified as a motor neuron disease, recent advances indicate that peripheral alterations at the level of the neuromuscular junction (NMJ), involving the muscle, and axons of the sensory-motor system, occur early, and may even precede motor neuron loss. In the present study, we used a mouse model of slow progressive (type III) SMA, whereby the absence of the mouse SMN protein is compensated by the expression of two human genes (heterozygous SMN1A2G, and SMN2). This leads to late disease onset and prolonged survival, which allows for dissecting slow degenerative steps operating early in SMA pathogenesis. In this purely morphological study carried out at transmission electron microscopy, we extend the examination of motor neurons and proximal axons towards peripheral components, including distal axons, muscle fibers, and also muscle spindles. We document remarkable ultrastructural alterations being consistent with early peripheral denervation in SMA, which may shift the ultimate anatomical target in neuromuscular disease from the spinal cord towards the muscle. This concerns mostly mitochondrial alterations within distal axons and muscle, which are quantified here through ultrastructural morphometry. The present study is expected to provide a deeper knowledge of early pathogenic mechanisms in SMA.
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Affiliation(s)
- Federica Fulceri
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | | | - Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - Carla L Busceti
- I.R.C.C.S. Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy
| | - Larisa Ryskalin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - Paola Lenzi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - Francesco Fornai
- I.R.C.C.S. Neuromed, Via Atinense 18, 86077, Pozzilli, IS, Italy. .,Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126, Pisa, Italy.
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Bukharaeva E, Khuzakhmetova V, Dmitrieva S, Tsentsevitsky A. Adrenoceptors Modulate Cholinergic Synaptic Transmission at the Neuromuscular Junction. Int J Mol Sci 2021; 22:ijms22094611. [PMID: 33924758 PMCID: PMC8124642 DOI: 10.3390/ijms22094611] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023] Open
Abstract
Adrenoceptor activators and blockers are widely used clinically for the treatment of cardiovascular and pulmonary disorders. More recently, adrenergic agents have also been used to treat neurodegenerative diseases. Recent studies indicate a location of sympathetic varicosities in close proximity to neuromuscular junctions. The pressing question is whether there could be any effects of endo- or exogenous catecholamines on cholinergic neuromuscular transmission. It was shown that the pharmacological stimulation of adrenoceptors, as well as sympathectomy, can affect both acetylcholine release from motor nerve terminals and the functioning of postsynaptic acetylcholine receptors. In this review, we discuss the recent data regarding the effects of adrenergic drugs on neurotransmission at the neuromuscular junction. The elucidation of the molecular mechanisms by which the clinically relevant adrenomimetics and adrenoblockers regulate quantal acetylcholine release from the presynaptic nerve terminals and postsynaptic sensitivity may help in the design of highly effective and well-tolerated sympathomimetics for treating a number of neurodegenerative diseases accompanied by synaptic defects.
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Limanaqi F, Biagioni F, Mastroiacovo F, Polzella M, Lazzeri G, Fornai F. Merging the Multi-Target Effects of Phytochemicals in Neurodegeneration: From Oxidative Stress to Protein Aggregation and Inflammation. Antioxidants (Basel) 2020; 9:antiox9101022. [PMID: 33092300 PMCID: PMC7589770 DOI: 10.3390/antiox9101022] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 02/08/2023] Open
Abstract
Wide experimental evidence has been provided in the last decade concerning the neuroprotective effects of phytochemicals in a variety of neurodegenerative disorders. Generally, the neuroprotective effects of bioactive compounds belonging to different phytochemical classes are attributed to antioxidant, anti-aggregation, and anti-inflammatory activity along with the restoration of mitochondrial homeostasis and targeting alterations of cell-clearing systems. Far from being independent, these multi-target effects represent interconnected events that are commonly implicated in the pathogenesis of most neurodegenerative diseases, independently of etiology, nosography, and the specific misfolded proteins being involved. Nonetheless, the increasing amount of data applying to a variety of neurodegenerative disorders joined with the multiple effects exerted by the wide variety of plant-derived neuroprotective agents may rather confound the reader. The present review is an attempt to provide a general guideline about the most relevant mechanisms through which naturally occurring agents may counteract neurodegeneration. With such an aim, we focus on some popular phytochemical classes and bioactive compounds as representative examples to design a sort of main highway aimed at deciphering the most relevant protective mechanisms which make phytochemicals potentially useful in counteracting neurodegeneration. In this frame, we emphasize the potential role of the cell-clearing machinery as a kernel in the antioxidant, anti-aggregation, anti-inflammatory, and mitochondrial protecting effects of phytochemicals.
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Affiliation(s)
- Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy;
| | - Francesca Biagioni
- Istituto di Ricovero e Cura a Carattere Scientifico Neuromed, Via Atinense 18, 86077 Pozzilli, Italy; (F.B.); (F.M.)
| | - Federica Mastroiacovo
- Istituto di Ricovero e Cura a Carattere Scientifico Neuromed, Via Atinense 18, 86077 Pozzilli, Italy; (F.B.); (F.M.)
| | - Maico Polzella
- Aliveda Laboratories, Viale Karol Wojtyla 19, 56042 Crespina Lorenzana, Italy;
| | - Gloria Lazzeri
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy;
- Correspondence: (G.L.); (F.F.)
| | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy;
- Istituto di Ricovero e Cura a Carattere Scientifico Neuromed, Via Atinense 18, 86077 Pozzilli, Italy; (F.B.); (F.M.)
- Correspondence: (G.L.); (F.F.)
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Girardin SE, Cuziol C, Philpott DJ, Arnoult D. The eIF2α kinase HRI in innate immunity, proteostasis, and mitochondrial stress. FEBS J 2020; 288:3094-3107. [DOI: 10.1111/febs.15553] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/09/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Stephen E. Girardin
- Department of Laboratory Medicine and Pathobiology University of Toronto ON Canada
| | - Camille Cuziol
- INSERM UMR_S 1197 Hôpital Paul Brousse Villejuif France
- Université Paris‐Saclay France
| | | | - Damien Arnoult
- INSERM UMR_S 1197 Hôpital Paul Brousse Villejuif France
- Université Paris‐Saclay France
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The Ubiquitin Proteasome System in Neuromuscular Disorders: Moving Beyond Movement. Int J Mol Sci 2020; 21:ijms21176429. [PMID: 32899400 PMCID: PMC7503226 DOI: 10.3390/ijms21176429] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022] Open
Abstract
Neuromuscular disorders (NMDs) affect 1 in 3000 people worldwide. There are more than 150 different types of NMDs, where the common feature is the loss of muscle strength. These disorders are classified according to their neuroanatomical location, as motor neuron diseases, peripheral nerve diseases, neuromuscular junction diseases, and muscle diseases. Over the years, numerous studies have pointed to protein homeostasis as a crucial factor in the development of these fatal diseases. The ubiquitin-proteasome system (UPS) plays a fundamental role in maintaining protein homeostasis, being involved in protein degradation, among other cellular functions. Through a cascade of enzymatic reactions, proteins are ubiquitinated, tagged, and translocated to the proteasome to be degraded. Within the ubiquitin system, we can find three main groups of enzymes: E1 (ubiquitin-activating enzymes), E2 (ubiquitin-conjugating enzymes), and E3 (ubiquitin-protein ligases). Only the ubiquitinated proteins with specific chain linkages (such as K48) will be degraded by the UPS. In this review, we describe the relevance of this system in NMDs, summarizing the UPS proteins that have been involved in pathological conditions and neuromuscular disorders, such as Spinal Muscular Atrophy (SMA), Charcot-Marie-Tooth disease (CMT), or Duchenne Muscular Dystrophy (DMD), among others. A better knowledge of the processes involved in the maintenance of proteostasis may pave the way for future progress in neuromuscular disorder studies and treatments.
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