Methamphetamine (METH) is abused worldwide, and it represents a threat for public health. METH exposure induces a variety of detrimental effects. In fact, METH produces a number of oxidative species, which lead to lipid peroxidation, protein misfolding, and nuclear damage. Cell clearing pathways such as ubiquitin‐proteasome (UP) and autophagy (ATG) are involved in METH‐induced oxidative damage. Although these pathways were traditionally considered to operate as separate metabolic systems, recent studies demonstrate their interconnection at the functional and biochemical level. Very recently, the convergence between UP and ATG was evidenced within a single organelle named autophagoproteasome (APP), which is suppressed by mTOR activation. In the present research study, the occurrence of APP during METH toxicity was analyzed. In fact, coimmunoprecipitation indicates a binding between LC3 and P20S particles, which also recruit p62 and alpha‐synuclein. The amount of METH‐induced toxicity correlates with APP levels. Specific markers for ATG and UP, such as LC3 and P20S in the cytosol, and within METH‐induced vacuoles, were measured at different doses and time intervals following METH administration either alone or combined with mTOR modulators. Western blotting, coimmunoprecipitation, light microscopy, confocal microscopy, plain transmission electron microscopy, and immunogold staining were used to document the effects of mTOR modulation on METH toxicity and the merging of UP with ATG markers within APPs. METH‐induced cell death is prevented by mTOR inhibition, while it is worsened by mTOR activation, which correlates with the amount of autophagoproteasomes. The present data, which apply to METH toxicity, are also relevant to provide a novel insight into cell clearing pathways to counteract several kinds of oxidative damage.

α-Synuclein (α-syn) is a protein involved in neuronal degeneration. However, the family of synucleins has recently been demonstrated to be involved in the mechanisms of oncogenesis by selectively accelerating cellular processes leading to cancer. Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human cancers, with a specifically high neurotropism. The molecular bases of this biological behavior are currently poorly understood. Here, α-synuclein was analyzed concerning the protein expression in PDAC and the potential association with PDAC neurotropism. Tumor (PDAC) and extra-tumor (extra-PDAC) samples from 20 patients affected by PDAC following pancreatic resections were collected at the General Surgery Unit, University of Pisa. All patients were affected by moderately or poorly differentiated PDAC. The amount of α-syn was compared between tumor and extra-tumor specimen (sampled from non-affected neighboring pancreatic areas) by using in situ immuno-staining with peroxidase anti-α-syn immunohistochemistry, α-syn detection by using Western blotting, and electron microscopy by using α-syn-conjugated immuno-gold particles. All the methods consistently indicate that each PDAC sample possesses a higher amount of α-syn compared with extra-PDAC tissue. Moreover, the expression of α-syn was much higher in those PDAC samples from tumors with perineural infiltration compared with tumors without perineural infiltration.

Hypophosphatasia (HPP) is an inherited metabolic disease caused by deficient tissue‐nonspecific alkaline phosphatase (ALP) activity and characterized by skeletal and nonskeletal symptoms, including muscle weakness and fatigue. We hypothesized that mitochondrial respiration is impaired in muscle in HPP, independent of skeletal manifestations, and that the second‐generation ALP enzyme replacement therapy (ERT) efzimfotase alfa improves respiration. Akp2GW ^−/− mice were used for this purpose. Body weight, bone mineralization, and survival were validated in Akp2GW ^−/− mice versus Akp2 ^−/− mice, an established model of HPP. No significant differences were found, validating the Akp2GW ^−/− model. Respiratory outcomes were measured in skeletal muscle fiber bundles in age‐ and sex‐matched Akp2GW ^−/− and Akp2GW ^+/+ (wild‐type) mice; bone mineralization was assessed. Mean maximal respiration and mitochondrial spare respiratory capacity (SRC) in vehicle‐treated Akp2GW ^−/− mice were 37% and 30% of values from wild‐type mice, respectively, independent of skeletal manifestations. Efzimfotase alfa treatment significantly improved maximal respiration in tissue from Akp2GW ^−/− mice by 147% versus vehicle ( p = 0.0059) and improved SRC by 262% versus vehicle ( p = 0.0008). Mean maximal respiration and SRC in tissue from efzimfotase alfa‐treated Akp2GW ^−/− mice were 92% and 107%, respectively, of tissue from wild‐type mice. Cellular ultrastructure of muscle biopsies from people with HPP showed atypical mitochondrial morphology, including branching cristae and dispersed matrix. In a mouse model of HPP, we show that the altered mitochondrial respiration in skeletal muscle is improved by ERT and that HPP is characterized by altered muscle mitochondrial morphology in humans. Together, these data suggest ERT could improve muscular symptoms in HPP.

Chronic hepatitis C virus (HCV) infection is an established risk factor for B-cell lymphoproliferative disorders and represents a paradigmatic model of infection-driven lymphomagenesis. Although direct-acting antivirals have markedly reduced the burden of HCV-related disease, HCV-associated lymphomas continue to occur. Moreover, HCV screening remains incomplete in some geographical areas and healthcare settings, leaving a substantial proportion of infected individuals unaware of their status. This narrative review integrates current evidence on the mechanisms linking chronic HCV infection to mixed cryoglobulinemia and overt B-cell non-Hodgkin lymphoma. HCV lymphotropism and persistent antigenic stimulation could initially promote the selection and expansion of autoreactive B-cell clones, while mixed cryoglobulinemia represents the most informative pre-lymphomatous risk condition. Cytokine-mediated survival signals, particularly those involving B-cell activating factor, reinforce clonal persistence and cooperate with host genetic susceptibility, impaired apoptotic control, and activation-induced cytidine deaminase-mediated genomic instability. The progressive acquisition of somatic driver mutations, copy-number alterations, and epigenetic and transcriptomic changes may enable selected clones to escape functional anergy and become increasingly independent of the original viral stimulus that, in turn, represents an initial trigger of the lymphoproliferative process. Recurrent abnormalities converge on NF-κB, NOTCH, chromatin-regulatory, apoptotic, and cell-cycle pathways, although HCV-associated lymphomas remain molecularly heterogeneous. Emerging microRNA profiles further contribute to the molecular characterization of the transition from chronic infection and cryoglobulinemia to lymphoma. Despite the availability of highly effective antiviral therapies, HCV-associated lymphomagenesis remains clinically relevant and continues to provide an especially informative model for understanding how chronic viral infection can drive human cancer development.