Lonp1 is a mitochondrial protease that degrades oxidized and damaged proteins, assists protein folding, and contributes to the maintenance of mitochondrial DNA. A higher expression of LonP1 has been associated with higher tumour aggressiveness. Besides the full-length isoform (ISO1), we identified two other isoforms of Lonp1 in humans, resulting from alternative splicing: Isoform-2 (ISO2) lacking aa 42-105 and isoform-3 (ISO3) lacking aa 1-196. An inspection of the public database TSVdb showed that ISO1 was upregulated in lung, bladder, prostate, and breast cancer, ISO2 in all the cancers analysed (including rectum, colon, cervical, bladder, prostate, breast, head, and neck), ISO3 did not show significant changes between cancer and normal tissue. We overexpressed ISO1, ISO2, and ISO3 in SW620 cells and found that the ISO1 isoform was exclusively mitochondrial, ISO2 was present in the organelle and in the cytoplasm, and ISO3 was exclusively cytoplasmatic. The overexpression of ISO1 and, at a letter extent, of ISO2 enhanced basal, ATP-linked, and maximal respiration without altering the mitochondria number or network, mtDNA amount. or mitochondrial dynamics. A higher extracellular acidification rate was observed in ISO1 and ISO2, overexpressing cells, suggesting an increase in glycolysis. Cells overexpressing the different isoforms did not show a difference in the proliferation rate but showed a great increase in anchorage-independent growth. ISO1 and ISO2, but not ISO3, determined an upregulation of EMT-related proteins, which appeared unrelated to higher mitochondrial ROS production, nor due to the activation of the MEK ERK pathway, but rather to global metabolic reprogramming of cells.

Senescence of the immune system is characterized by a state of chronic, subclinical, low-grade inflammation termed ‘inflammaging', with increased levels of proinflammatory cytokines, both at the tissue and systemic levels. Age-related inflammation can be mainly driven by self-molecules with immunostimulant properties, named Damage/death Associated Molecular Patterns (DAMPs), released by dead, dying, injured cells or aged cells. Mitochondria are an important source of DAMPs, including mitochondrial DNA — the small, circular, double-stranded DNA molecule found in multiple copies in the organelle. mtDNA can be sensed by at least three molecules: the Toll-like receptor 9, the NLRP3 inflammasomes, and the cyclic GMP–AMP synthase (cGAS). All these sensors can lead to the release of proinflammatory cytokines when engaged. The release of mtDNA by damaged or necrotic cells has been observed in several pathological conditions, often aggravating the course of the disease. Several lines of evidence indicate that the impairment of mtDNA quality control and of the organelle homeostasis associated with aging determines an increase in the leakage of mtDNA from the organelle to the cytosol, from the cell to the extracellular space, and into plasma. This phenomenon, mirrored by an increase in mtDNA circulating levels in elderly people, can lead to the activation of different innate immune cell types, sustaining the chronic inflammatory status that is characteristic of aging.

The mitochondrial protease Lonp1 is a multifunctional enzyme that regulates crucial mitochondrial functions, including the degradation of oxidized proteins, folding of imported proteins and maintenance the correct number of copies of mitochondrial DNA. A series of recent studies has put Lonp1 at the center of the stage in the homeostasis of cardiomyocytes and muscle skeletal cells. During heart development, Lonp1 allows the metabolic shift from anaerobic glycolysis to mitochondrial oxidative phosphorylation. Knock out of Lonp1 arrests heart development and determines cardiomyocyte apoptosis. In adults, Lonp1 acts as a cardioprotective protein, as its upregulation mitigates cardiac injury by preventing the oxidative damage of proteins and lipids, and by preserving mitochondrial redox balance. In skeletal muscle, Lonp1 is crucial for cell development, as it mediates the activation of PINK1/Parkin pathway needed for proper myoblast differentiation. Skeletal muscle-specific ablation of Lonp1 in mice causes reduced muscle fiber size and strength due to the accumulation of mitochondrial-retained protein in muscle. Lonp1 expression and activity decline with age in different tissues, including skeletal muscle, and are associated with a functional decline and structural impairment of muscle fibers. Aerobic exercise increases unfolded protein response markers including Lonp1 in the skeletal muscle of aged animals and is associated with muscle functional recovery. Finally, mutations of Lonp1 cause a syndrome named CODAS (Cerebral, Ocular, Dental, Auricular, and Skeletal anomalies) characterized by the impaired development of multiple organs and tissues, including myocytes. CODAS patients show hypotonia and ptosis, indicative of skeletal muscle reduced performance. Overall, this body of observations points Lonp1 as a crucial regulator of mitochondrial functions in the heart and in skeletal muscle.

Aims Whole-body cryotherapy (WBC) is a recently widely strategy used for muscle recovery after injury that can to activate inflammatory response. WBC consists of short exposure, of about 2-3 minutes, to dry air at cryogenic temperatures up to -190 °C. The aim of our study is to analyze WBC effects on metabolic, hormonal, and immunological responses of non-professional football players (NPFPs). Methods and results Nine male NPFPs (age: 20 ± 2 years) on the same team are recruited and, in particular, they played and trained each day before, during, and after WBC treatment. We collected NPFPs blood samples immediately before WBC and after 5 once-day sessions, then we evaluated a set consisting of 50 analytes, including hormones profile, haematologic parameters, and serum chemistry. We proceeded with monocytes (Mo) phenotyping and then we investigated the concentration of some plasmatic markers with anti-inflammatory effects (IL2RA, IL1RN) or typically increased during inflammation [CCL2, IL-18, free mitochondrial DNA (mtDNA)]. WBC treatment (WBC-t) lead to a decrease not only in mean platelet volume, mean corpuscular haemoglobin, and ferritin levels, but also in testosterone and estradiol levels, even if they remain within the normal ranges. This treatment is also responsible for total Mo increased and, in particular, a reduction of classical Mo has been demonstrated in parallel with an increase of non-classical ones. Moreover, each Mo subset shows lower expression of CXCR4. Considering pro-inflammatory molecules, IL1RA showed a tendency to decrease, while IL1RN and IL18 decreased in plasma after WBC-t. Conversely, circulating mtDNA levels appeared unaltered by treatment. Conclusions The differences detected in monocyte subset after WBC-t suggest that, in this condition, Mo could be redistributed into the surrounding tissue. In addition, CXCR4 reduction in Mo subsets could be due to their differentiation process. Hence, WBC could promote Mo differentiation through a mechanism that is still unknown. Since WBC seems to regulate the innate immune system in the enrolled NPFPs, it could have a role in tissue repair beyond a beneficial anti-inflammatory effect.

In recent years, the consumption of energy drinks (EDs) has increased constantly among young people because of their capacity to enhance alertness and improve mental and physical performance, reducing fatigue. EDs are beverages containing a high and variable amount of caffeine, which exerts effects on many tissues of the cardiovascular system. In addition to caffeine, they contain several other psychoactive substances including the amino acid taurine, the glucose derivative glucuronolactone, as well as herbal extracts such as guaranà (another source of caffeine, with caffeine-like effects) and ginseng, often present in not well-known concentration. In our project we aim to evaluate whether the consumption of EDs causes alterations in the organs involved in their contact, absorption and metabolism in an animal model, i.e. the rat. We used 28 Sprague Dawley adult male rats, weighing 230–250 g and fed with a standard laboratory diet, randomly divided into four groups (N = 7). Every group received a different treatment (ED, soda-cola, sweetened coffee or water-controls-) for 5 days. All animals were anesthetized and underwent histological analysis and blood sampling at the end of the treatment. We observed eosinophilic infiltrates in gastrointestinal tract, but not in cardiovascular system. We quantified various indicators of tissue damage and cytokines in plasma, including ICAM-1, L-selectin, TIMP-1, VEGF, IL-10, IL-2, IL-4, IL-6, IL-1β, IL-13, IL-33, TNF-α, and IFN-γ. In contrast with the eosinophilic infiltration, we did not detect a systemic increase of Th2 cytokines (i.e. IL-4 and IL-13) after treatment: thus, even if the experiments evaluating the possible presence of an unbalanced Th2 response in the tissues featured by eosinophilic infiltration are still lacking, we exclude further deepening on Th2 immune responses. Interestingly, we observed a decrease of TIMP-1 in plasma from rats orally supplemented with ED, soda-cola or sweetened coffee compared to animals treated with water. TIMP-1 is a major player in preserving tissue integrity and controlling wound healing by balancing the enzymatic activity of matrix metalloproteinases (MMPs) and regulating extracellular matrix turnover. Moreover, elevated levels of the adhesion molecules ICAM-1 and L-selectin were found in plasma from rats receiving ED or soda-cola, together with a high concentration of IL-33 in animals assuming the ED. The circulating form of ICAM-1 is associated with inflammation, particularly due to endothelial damage, and L-selectin and IL-33 play an important role in inflammatory conditions as well. These observations suggest that the consumption of EDs could alter the architecture, and hence function, of the organs involved in their contact, absorption and metabolism. Indeed, the alterations we observed in the periphery could reflect the establishment of inflammation and deregulated mechanisms of damage repair locally in the target tissues.