Activation of autophagy and suspended apoptosis in skeletal muscle of inclusion body myositis

Inclusion Body Myositis (IBM) is characterized by rimmed vacuole formation and misfolded protein accumulation, both depending on lysosome dysfunction. In skeletal muscle, selective protein degradation is allowed by macroautophagy. A proper balance in degradation and accumulation of proteins and organelles is critical for cell survival. Extracellular signal-regulated protein kinase (ERK1/2) is essential in cell survival, but recent evidence suggests that it is also necessary for autophagy. Alteration in subcellular localization of ERK promotes cell death either via autophagic death or via apoptosis upstream caspase-3. Moreover, in IBM myocytes there is no convincing evidence for apoptosis. Here, we correlated the expression level of autophagic and apoptotic molecules with that of ERK2 by analysing, with immunohistochemistry (IHC) and western blot (WB) methods, immunolocalization and expression of a panel of molecules directly involved and/or associated with the disease histopathogenesis: coated vesicles protein clathrin, mannose-6-phosphate receptor (M6PR), autophagy related proteins Beclin1 and ATG5, microtubule associated protein light chain LC3a and LC3b, Apoptotic Protease Activating Factor 1 (APAF1), Caspase-3, ERK2, and the specific IBM marker SMI31. Muscle biopsy specimens were obtained from 10 patients with sporadic IBM, 1 familial IBM patient, 1 amyotrophic lateral sclerosis patient, 1 patient with polymyositis with prominent mitochondrial pathology and 9 non myophatic patients as control specimens. IHC studies of expression and colocalization revealed an increase of clathrin, Beclin1, ATG5, and LC3 immunoreactivity, mainly observed in the sarcoplasm of small, atrophic fibres in all diseased specimens compared to controls. By WB analysis, expression level of both APAF1 and Caspase-3 did not significantly change between patients and controls, whereas the level of expression of ERK2 and autophagy markers seemed to inversely correlate. The results demonstrated that transport of newly synthesized lysosome enzymes and formation of autophagic vacuoles are both activated in IBM muscle. ERK2 phosphorylating activity is probably involved in rescue attempt to overcome the cell injury rather than directly stimulating the cell death. During IBM, the apoptotic cascade seems to be suspended, however,under the effect of cytotoxic stimuli, protective autophagy may switch to autophagic programmed cell death

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La plasmaferesi nelle malattie neuromuscolari. Casistica personale.

Sono riferiti i risultati del trattamento di 8 pazienti con miastenia grave e 26 pazienti con poliradicolonevrite. Nella miastenia grave il trattamento fu efficace nell'85% dei casi. Buoni risultati sono stati ottenuti nell'80 dei pazienti con poliradicolonevrite. In tutti i casi la plasmaferesi fu effettuata nelle fasi precoci di malattia. Nei casi di poliradicolonevrite cronica il trattamento fu meno efficace

Autophagy markers LC3 and p62 accumulate in immune‐mediated necrotizing myopathy

Introduction: The molecular mechanism of immune-mediated necrotizing myopathy (IMNM) remains unknown. Autophagy impairment, described in autoimmune diseases, is a key process in myofibre protein degradation flux and muscle integrity, and has not been studied in IMNM. Methods: Muscle biopsies from patients with IMNM (n=40), dermatomyositis (DM, 24), polymyositis (PM, 8), polymyositis with mitochondrial pathology (4), sporadic inclusion body myositis (sIBM, 8), and controls (6) were compared by immunohistochemistry. Results: The proportions of myofibres containing autophagy markers LC3b and p62 were higher in IMNM than in DM or PM, and correlated with creatine kinase levels. In IMNM, compartmentalized LC3b puncta were located in regenerating and degenerating myofibres surrounded by major histocompatibility complex type II+ inflammatory cells. Several IMNM myofibres accumulated ubiquitin and misfolded protein. Discussion: The detection of LC3b+ or p62+ myofibres could be used in differentiating IMNM from PM. The identification of autophagy-modifying molecules potentially could improve patients outcomes

An Integrated approach for structural behavior characterization of Gravina Bridge (Matera, Southern Italy)

An integrated geophysical approach using non-invasive, non-destructive, and cost-effective seismic and electromagnetic techniques has been implemented to recognize the static and dynamic properties (i.e. eigenfrequencies, equivalent viscous damping factors, and related modal shapes) of the Gravina Bridge and its interaction with foundation soils. The “Gravina” is a bow-string bridge located on outcropping calcarenites in the city of Matera (Southern Italy) and develops for 144 m along a steel-concrete deck. The foundation soil characteristics have been evaluated by means of three high-resolution geo-electrical tomographies, one Vs velocity profile, and two site amplification functions. The main structural characteristics of the bridge have been estimated through permanent and on-demand monitoring using seismic and electromagnetic sensing. The former consisted of accelerometers and velocimeters installed with different geometrical arrangements for permanent earthquake and on-demand ambient vibration test recordings. The electromagnetic sensing was realized by a microwave radar interferometer placed below the deck to measure the displacements of the whole scenario illuminated by the antenna beam providing a continuous mapping of the static and dynamic displacements of the entire target. Acquired data have been analyzed in both frequency and time-frequency domain with the aim to study the stationary and non-stationary response of the monitored bridge. These experimental campaigns allowed us to assess the robustness of the proposed approach and to set up the zero-time reference point of the bridge dynamic parameters