Acetylcarnitine and cellular stress response: roles in nutritional redox homeostasis and regulation of longevity genes

Aging is associated with a reduced ability to cope with physiological challenges. Although the mechanisms underlying age-related alterations in stress tolerance are not well defined, many studies support the validity of the oxidative stress hypothesis, which suggests that lowered functional capacity in aged organisms is the result of an increased generation of reactive oxygen and nitrogen species. Increased production of oxidants in vivo can cause damage to intracellular macromolecules, which can translate into oxidative injury, impaired function and cell death in vulnerable tissues such as the brain. To survive different types of injuries, brain cells have evolved networks of responses, which detect and control diverse forms of stress. This is accomplished by a complex network of the so-called longevity assurance processes, which are composed of several genes termed vitagenes. Among these, heat shock proteins form a highly conserved system responsible for the preservation and repair of the correct protein conformation. The heat shock response contributes to establishing a cytoprotective state in a wide variety of human diseases, including inflammation, cancer, aging and neurodegenerative disorders. Given the broad cytoprotective properties of the heat shock response, there is now a strong interest in discovering and developing pharmacological agents capable of inducing the heat shock response. Acetylcarnitine is proposed as a therapeutic agent for several neurodegenerative disorders, and there is now evidence that it may play a critical role as modulator of cellular stress response in health and disease states. In the present review, we first discuss the role of nutrition in carnitine metabolism, followed by a discussion of carnitine and acetyl-l-carnitine in mitochondrial dysfunction, in aging, and in age-related disorders. We then review the evidence for the role of acetylcarnitine in modulating redox-dependent mechanisms leading to up-regulation of vitagenes in brain, and we also discuss new approaches for investigating the mechanisms of lifetime survival and longevity.     

Submandibular rhabdomyoma: a case report

BACKGROUND: The cytologic diagnosis of extracardiac rhabdomyoma is frequently hampered by its rarity and resemblance to various tumors. In this regard, the infrequent occurrence has hindered its prompt and early recognition. It is also confused with other tumors because of similarities in clinical and cytologic presentations. CASE: A submandibular rhabdomyoma occurred in an otherwise-healthy, 62-year-old man. The neoplasm was firstly diagnosed by fine needle aspiration cytology (FNAC. Complete local excision without radical surgery was performed. Histologic findings confirmed the cytologic diagnosis of adult rhabdomyoma. Treatment-related complications were minimal, and there was no evidence of recurrent disease 6 years later. CONCLUSION: Helpful FNAC features and immunocytochemical results permitted an early diagnosis and spared the patient unnecessary radical surgery.     

Proteomics characterization of protein adsorption onto hemodialysis membranes

Protein-adsorptive properties are a key feature of membranes used for hemodialysis treatment. Protein adsorption is vital to the biocompatibility of a membrane material and influences membrane's performance. The object of the present study is to investigate membrane biocompatibility by correlating the adsorbed proteome repertoire with structural feature of the membrane surfaces. Minidialyzers of identical structural characteristics composed of either cellulose diacetate or ethylenevinyl alcohol materials were employed to develop an ex vivo apparatus to investigate protein adsorption. Adsorbed proteins were eluted by a strong chaotropic buffer condition and investigated by 2-DE coupled to both MALDI-TOF mass spectrometry (MS) mass fingerprinting and fragmentation analysis on a nanoLC-MS/MS hybrid instrument. Membrane surface characterization included evaluation of roughness (atomic force microscopy), elemental chemical composition (X-ray-photoelectron-spectroscopy), and hydrophilicity (pulsed nuclear magnetic resonance). The present study identifies a number of different proteins as common or characteristic of filter material interaction, showing that proteomic techniques are a promising approach for the investigation of proteins surface-adsorbed onto hemodialysis membrane. Proteomic analysis enables the characterization of protein layers of unknown composition.     

Encoding of Time-varying Stimuli in Populations of Cultured Neurons

We wondered whether random populations of dissociated cultured cortical neurons, despite of their lack of structure and/or regional specialization, are capable of modulating their neural activity as the effect of a time-varying stimulation – a simulated ‘sensory’ afference. More specifically, we used localized low-frequency, non-periodic trains of stimuli to simulate sensory afferences, and asked how much information about the original trains of stimuli could be extracted from the neural activity recorded at the different sites. Furthermore, motivated by the results of studies performed both in vivo and in vitro on different preparations, which suggested that isolated spikes and bursts may play different roles in coding time-varying signals, we explored the amount of such ‘sensory’ information that could be associated to these different firing modes. Finally, we asked whether and how such ‘sensory’ information is transferred from the sites of stimulation (i.e., the ‘sensory’ areas), to the other regions of the neural populations. To do this we applied stimulus reconstruction techniques and information theoretic concepts that are typically used to investigate neural coding in sensory systems. Our main results are that (1) slow variations of the rate of stimulation are coded into isolated spikes and in the time of occurrence of bursts (but not in the bursts’ temporal structure); (2) increasing the rate of stimulation has the effect of increasing the proportion of isolated spikes in the average evoked response and their importance in coding for the stimuli; and, (3) the ability to recover the time course of the pattern of stimulation is strongly related to the degree of functional connectivity between stimulation and recording sites. These observations parallel similar findings in intact nervous systems regarding the complementary roles of bursts and tonic spikes in encoding sensory information. Our results also have interesting implications in the field of neuro-robotic interfaces. In fact, the ability of populations of neurons to code information is a prerequisite for obtaining hybrid systems, in which neuronal populations are used to control external devices.     

Involvement of quorum sensing and RpoS in rice seedling blight caused by Burkholderia plantarii

Burkholderia plantarii is a plant pathogen responsible for causing rice seedling blight. The molecular mechanisms responsible for this pathogenicity are currently unknown. In this study, we report the identification and characterization of N-acyl homoserine lactone quorum sensing and the stationary phase RpoS sigma factor of B. plantarii. Both global regulatory systems are involved in causing rice seedling blight. This is the first report of gene regulators of B. plantarii implicated in the disease.     

Genotype-dependent priming to self- and xeno-cannibalism in heterozygous and homozygous lymphoblasts from patients with Huntington's disease

In the present work, we studied the mitochondrial function and cell death pathway(s) in heterozygous and homozygous immortalized cell lines from patients with Huntington's disease (HD). Heterozygosis was characterized by specific alterations in mitochondrial membrane potential, a constitutive hyperpolarization state of mitochondria, and was correlated with an increased susceptibility to apoptosis. Lymphoblasts from homozygous patients, on the other hand, were characterized by a significant percentage of cells displaying autophagic vacuoles. These cells also demonstrated a striking attitude towards significant cannibalistic activity. Considering the pathogenic role of cell death in HD, our study provides new and useful insights into the role of mitochondrial dysfunction, i.e. hyperpolarization, in hijacking HD heterozygous cells towards apoptosis and HD homozygous cells towards a peculiar phenotype characterized by both self- and xeno-cannibalism. These events can, however, be viewed as an ultimate attempt to survive rather than a way to die. The present work underlines the possibility that HD-associated mitochondrial defects could tentatively be by-passed by the cells by activating cellular 'phagic' activities, including so-called 'mitophagy' and 'cannibalism', that only finally lead to cell death.     

Local anti-inflammatory effect and behavioral studies on new PDE4 inhibitors

Phosphodiesterase 4 (PDE4) inhibitors are effective anti-inflammatory drugs, although some adverse effects are observed in animals and humans. These effects have forced researchers to find new PDE4 inhibitors with less adverse effects. We recently reported the synthesis of novel heterocyclic-fused pyridazinones that inhibit PDE4. As a first step in the study of the anti-inflammatory properties of these compounds, we studied the effects of local administration of these pyridazinone derivatives in a mouse model of acute inflammation. We found that 6-Benzyl-3-methyl-4-phenylpyrazolo[3,4-d]pyridazin-7(6H)-one (CC4), ethyl 6,7-dihydro-6-ethyl-3-methyl-7-oxo-4-phenyl-thieno[2,3-d]pyridazine-2-carboxylate (CC6) and ethyl 6,7-dihydro-6-ethyl-3-methyl-4-phenyl-1H-pyrrolo[2,3-d]pyridazine-2-carboxylate (CC12) reduced the paw edema induced by zymosan in mice as rolipram (the PDE4 inhibitor prototype with anti-inflammatory activity) and indomethacin did. It is well known that rolipram locally administered induces some adverse effects such as hyperalgesia. Thus, we studied this effect after local administration of CC4, CC6 and CC12 in the formalin test. We found that CC6 induced hyperalgesic effects, whereas CC4 and CC12 did not change the nociceptive threshold. Furthermore, we found that rolipram and CC6 reduced locomotor activity, whereas CC4 and CC12 did not change locomotor performance of the mice. Since CC4 and CC12 neither affected the nociceptive threshold nor changed the locomotor performance of mice, they appear more suitable than CC6 for future studies on animals and could be developed as an anti-inflammatory drug for humans.