Skeletal Muscle Mitochondrial and Perilipin Content in a Cohort of Obese Subjects Undergoing Moderate and High Intensity Training

Obesity is a complex condition characterized by abnormal and excessive fat accumulation, resulting in an increased risk for severe health problems. Skeletal muscles play a major role in movement and fat catabolism, but the insulin resistance that comes with obesity makes it difficult to fulfill these tasks. In this study, we analyse two types of training protocols, moderate intensity continuous training (MICT) versus high intensity interval training (HIIT), in a cohort of obese subjects to establish which muscle adaptations favour fat consumption in response to exercise. Mitochondria play a role in fat oxidation. We found protein upregulation of mitochondrial biomarkers, TOMM20 and Cox-4, in HIIT but not in MICT, without detecting any shifts in fibre composition phenotype of the vastus lateralis in both training groups. Interestingly, both MICT and HIIT protocols showed increased protein levels of perilipin PLIN2, which is involved in the delivery and consumption of fats. HIIT also augmented perilipin PLIN5. Perilipins are involved in fat storage in skeletal muscles and their upregulation, along with the analysis of circulatory lipid profiles reported in the present study, suggest important adaptations induced by the two types of training protocols that favour fat consumption and weight loss in obese subjects

Effects of short-term unloading and active recovery on human motor unit properties, neuromuscular junction transmission and transcriptomic profile

Electrophysiological alterations of the neuromuscular junction (NMJ) and motor unit potential (MUP) with unloading are poorly studied. We aimed to investigate these aspects and the underlying molecular mechanisms with short-term unloading and active recovery (AR). Eleven healthy males underwent a 10-day unilateral lower limb suspension (ULLS) period, followed by 21-day AR based on resistance exercise. Quadriceps femoris (QF) cross-sectional area (CSA) and isometric maximum voluntary contraction (MVC) were evaluated. Intramuscular electromyographic recordings were obtained during 10% and 25% MVC isometric contractions from the vastus lateralis (VL). Biomarkers of NMJ molecular instability (serum c-terminal agrin fragment, CAF), axonal damage (neurofilament light chain) and denervation status were assessed from blood samples and VL biopsies. NMJ and ion channel transcriptomic profiles were investigated by RNA-sequencing. QF CSA and MVC decreased with ULLS. Increased CAF and altered NMJ transcriptome with unloading suggested the emergence of NMJ molecular instability, which was not associated with impaired NMJ transmission stability. Instead, increased MUP complexity and decreased motor unit firing rates were found after ULLS. Downregulation of ion channel gene expression was found together with increased neurofilament light chain concentration and partial denervation. The AR period restored most of these neuromuscular alterations. In conclusion, the human NMJ is destabilized at the molecular level but shows functional resilience to a 10-day unloading period at least at relatively low contraction intensities. However, MUP properties are altered by ULLS, possibly due to alterations in ion channel dynamics and initial axonal damage and denervation. These changes are fully reversed by 21 days of AR. (Figure presented.). Key points: We used integrative electrophysiological and molecular approaches to comprehensively investigate changes in neuromuscular integrity and function after a 10-day unilateral lower limb suspension (ULLS), followed by 21 days of active recovery in young healthy men, with a particular focus on neuromuscular junction (NMJ) and motor unit potential (MUP) properties alterations. After 10-day ULLS, we found significant NMJ molecular alterations in the absence of NMJ transmission stability impairment. These findings suggest that the human NMJ is functionally resilient against insults and stresses induced by short-term disuse at least at relatively low contraction intensities, at which low-threshold, slow-type motor units are recruited. Intramuscular electromyography analysis revealed that unloading caused increased MUP complexity and decreased motor unit firing rates, and these alterations could be related to the observed changes in skeletal muscle ion channel pool and initial and partial signs of fibre denervation and axonal damage. The active recovery period restored these neuromuscular changes

Ipotesi di ricostruzione dell’anfiteatro romano di Milano. Modellazione geometrica e tecniche generative per la simulazione esperienziale

Si descrive la ricostruzione virtuale dell’anfiteatro romano di Milano, di cui rimangono 8 setti di fondazione e alcune porzioni murarie, utilizzando un metodo grafico generativo. Dopo l’analisi comparata delle diverse ipotesi ricostruttive e l’esecuzione del rilievo, la ricerca ha verificato le rappresentazioni della geometria dell’anfiteatro impostando parametri e vincoli: ovale a 4 centri, rapporto tra larghezza e lunghezza 5:3 e triangolo generatore pitagorico. L’obbiettivo è testare le tecniche generative di simulazione esperienziale in ambito archeologico per una fruizione immersiva

Golgi Complex form and Function: A Potential Hub Role Also in Skeletal Muscle Pathologies?

A growing number of disorders has been associated with mutations in the components of the vesicular transport machinery. The early secretory pathway consists of Endoplasmic Reticulum, numerous vesicles, and the Golgi Complex (GC), which work together to modify and package proteins to deliver them to their destination. The GC is a hub organelle, crucial for organization of the other secretory pathway components. As a consequence, GC’s form and function are key players in the pathogenesis of several disorders. Skeletal muscle (SKM) damage can be caused by defective protein modifications and traffic, as observed in some Limb girdle muscular dystrophies. Interestingly, in turn, muscle damage in Duchenne dystrophic SKM cells also includes the alteration of GC morphology. Based on the correlation between GC’s form and function described in non-muscle diseases, we suggest a key role for this hub organelle also in the onset and progression of some SKM disorders. An altered GC could affect the secretory pathway via primary (e.g., mutation of a glycosylation enzyme), or secondary mechanisms (e.g., GC mis-localization in Duchenne muscles), which converge in SKM cell failure. This evidence induces considering the secretory pathway as a potential therapeutic target in the treatment of muscular dystrophies

FAMIN is a multifunctional purine enzyme enabling the purine nucleotide cycle

Mutations in FAMIN cause arthritis and inflammatory bowel disease in early childhood, and a common genetic variant increases the risk for Crohn's disease and leprosy. We developed an unbiased liquid chromatography-mass spectrometry screen for enzymatic activity of this orphan protein. We report that FAMIN phosphorolytically cleaves adenosine into adenine and ribose-1-phosphate. Such activity was considered absent from eukaryotic metabolism. FAMIN and its prokaryotic orthologs additionally have adenosine deaminase, purine nucleoside phosphorylase, and S-methyl-5′-thioadenosine phosphorylase activity, hence, combine activities of the namesake enzymes of central purine metabolism. FAMIN enables in macrophages a purine nucleotide cycle (PNC) between adenosine and inosine monophosphate and adenylosuccinate, which consumes aspartate and releases fumarate in a manner involving fatty acid oxidation and ATP-citrate lyase activity. This macrophage PNC synchronizes mitochondrial activity with glycolysis by balancing electron transfer to mitochondria, thereby supporting glycolytic activity and promoting oxidative phosphorylation and mitochondrial H+ and phosphate recycling

Statistical calibration of the Carlit index in the Pontine Island of Zannone

The WFD, adopted by the European Community requires that Member States achieve and maintain a good ecological status of all water bodies by 2015. In the marine context, the ecological status has to be quantied applying indexes based on appropriate key biological elements. The CARLIT index is a car- tographic monitoring tool enabling the EQR2 to be calculated using macroalgae in coastal hard bottoms as a key biological element. Here we investigate the role of Cystoseira amentacea var.stricta: a key macroalgae involved in the index denition. We analyze the relation between the algae presence and geomorphological character- istics of Pontine Islands coast through standard logistic regression and autologistc models to account for spatial correlation

The Contribution of Genetics to Muscle Disuse, Retraining, and Aging

Genetic background may partly explain differences in muscle responses to internal or external stimuli. Muscle disuse involves various degrees of skeletal muscle atrophy due to inactivity and mechanical unloading. Whether and to which extent genetic background impacts disuse atrophy and retraining in individuals of different ages are currently unclear. Here, we provide a brief overview of relevant literature on the contribution of genetics to muscle disuse, retraining, and aging, and offer a perspective on unanswered questions on the subject that may open new venues for research

Active older dancers have lower C-terminal Agrin fragment concentration, better balance and gait performance than sedentary peers

Motor neuron degeneration, denervation, neuromuscular junction (NMJ) fragmentation and loss of motor units (MUs), play a key-role in the development of sarcopenia. The aim of the present study was to investigate the beneficial effects of regular practice of dancing in physically active elders on concentration of C-terminal Agrin fragment (CAF), a marker of NMJ instability, muscle mass, strength, and physical performance in a group of 16 recreationally active older dancers (AOD; 70.1 \ub1 3.4 yr) compared to 15 age-matched sedentary peers (OS; 70.9 \ub1 6.2 yr). Circulating concentration of CAF was measured in serum, while morphology of the vastus lateralis and multifidus muscles was assessed by ultrasound imaging. In addition, the participants underwent two functional performance tests, the Timed Up and Go (TUG) and the 10-meter walk test (10-MWT), a lower and upper limb isometric strength test, a static and a dynamic balance test. Although no statistically significant differences were detected for both muscle morphology and isometric strength, higher CAF concentration (20%, p < 0.01) was found in OS. AOD showed a better performance in TUG (22%, p < 0.001), 10-MWT (17%, p < 0.001) and dynamic balance (25%, p < 0.01) than OS. Notably, CAF concentration correlated with dynamic balance performance (r = 0.3711, p < 0.05). Our results provide evidence that the regular practice of dancing in older age, together with non-structured light aerobic physical activities, is associated to lower CAF concentration and improved walking and balance performance. Our findings also suggest that NMJ instability, as indicated by elevated CAF serum concentration, seems to precede the loss of muscle size and alterations in muscle architecture normally associated with sarcopenia

Increased TFAM binding to mtDNA damage hot spots is associated with mtDNA loss in aged rat heart.

The well-known age-related mitochondrial dysfunction deeply affects heart because of the tissue’s large dependence on mitochondrial ATP provision. Our study revealed in aged rat heart a significant 25% decrease in mtDNA relative content, a significant 29% increase in the 4.8 Kb mtDNA deletion relative content, and a significant inverse correlation between such contents as well as a significant 38% decrease in TFAM protein amount. The TFAM-binding activity to specific mtDNA regions increased at those encompassing the mtDNA replication origins, D-loop and Ori-L. The same mtDNA regions were screened for different kinds of oxidative damage, namely Single Strand Breaks (SSBs), Double Strand Breaks (DSBs), abasic sites (AP sites) and oxidized bases as 7,8-dihydro-8-oxoguanine (8oxoG). A marked increase in the relative content of mtDNA strand damage (SSBs, DSBs and AP sites) was found in the D-loop and Ori-L regions in the aged animals, unveiling for the first time in vivo an age-related, non-stochastic accumulation of oxidative lesions in these two regions that appear as hot spots of mtDNA damage. The use of Formamidopyrimidine glycosylase (Fpg) demonstrated also a significant age-related accumulation of oxidized purines particularly in the D-loop and Ori-L regions. The detected increased binding of TFAM to the mtDNA damage hot spots in aged heart suggests a link between TFAM binding to mtDNA and loss of mitochondrial genome likely through hindrance of repair processes