AMPK in the central nervous system: physiological roles and pathological implications

5′ AMP-activated protein kinase (AMPK) is considered the master metabolic regulator in all eukaryotes, as it maintains cellular energy homeostasis in a variety of tissues, including the brain. In humans, alterations in AMPK activity can lead to a wide spectrum of metabolic disorders. The relevance of this protein kinase in the pathogenesis of diabetes and metabolic syndrome is now well established. On the contrary, correlations between AMPK and brain physiopathology are still poorly characterized. The aim of this review is to summarize and discuss the current knowledge about the prospective involvement of AMPK in the onset and the progression of different neurological diseases

An accidental diagnosis of optic nerve meningioma in a patient affected by thyroid eye disease

A 42-year-old woman presented to our hospital owing to a history of right-sided proptosis of 4 months duration, reporting no previous trauma, fever, or recent sinusitis. Her medical record included a diagnosis of Graves’ disease. The best corrected visual acuity (BCVA) was 20/20 and a 30.2 visual field test was normal. A 3-Tesla magnetic resonance imaging (MRI) revealed an orbital apex meningioma approaching the walls of the sulcus chiasmaticus. A subsequent 60.4 perimetry test showed bilateral nasal visual field defects, thus confirming the involvement of the optic nerve. The reported case focuses on the differential diagnosis with Thyroid Eye Disease (TED) and the subsequent follow-up

Fat Checking: Emerging Role of Lipids in Metabolism and Disease

Lipids are hydrophobic molecules involved in a plethora of biological functions; for example, they are employed for the storage of energy, serve as essential constituents of cell membranes and participate in the assembly of bilayer configuration [...]

Cholesterol metabolism is altered in Rett syndrome: A study on plasma and primary cultured fibroblasts derived from patients

Rett (RTT) syndrome is a severe neurological disorder that affects almost exclusively females. Several detectable mutations in the X-linked methyl-CpG-binding protein 2 gene (MECP2) are responsible for the onset of the disease. MeCP2 is a key transcription regulator involved in gene silencing via methylation-dependent remodeling of chromatin. Recent data highlight that lipid metabolism is perturbed in brains and livers of MECP2-null male mice. In addition, altered plasma lipid profile in RTT patients has been observed. Thus, the aim of the work is to investigate the protein network involved in cholesterol homeostasis maintenance on freshly isolated fibroblasts and plasma from both RTT and healthy donors. To this end, protein expression of 3-hydroxy-3methyl glutaryl Coenzyme A reductase (HMGR), sterol regulatory element binding proteins (SREBPs), low density lipoprotein receptor (LDLr) and scavenger receptor B-1 (SRB-1) was assessed in cultured skin fibroblasts from unaffected individuals and RTT patients. In addition, lipid profile and the abundance of proprotein convertase subtilisin/kexin type 9 (PCSK9) were analyzed on plasma samples. The obtained results demonstrate that the main proteins belonging to cholesterol regulatory network are altered in RTT female patients, providing the proof of principle that cholesterol metabolism may be taken into account as a new target for the treatment of specific features of RTT pathology

Epigenetic targeting of bromodomain protein BRD4 counteracts cancer cachexia and prolongs survival

Cancer cachexia is a devastating metabolic syndrome characterized by systemic inflammation and massive muscle and adipose tissue wasting. Although it is responsible for approximately one-third of cancer deaths, no effective therapies are available and the underlying mechanisms have not been fully elucidated. We previously identified the bromodomain and extra-terminal domain (BET) protein BRD4 as an epigenetic regulator of muscle mass. Here we show that the pan-BET inhibitor (+)-JQ1 protects tumor-bearing mice from body weight loss and muscle and adipose tissue wasting. Remarkably, in C26-tumor-bearing mice (+)-JQ1 administration dramatically prolongs survival, without directly affecting tumor growth. By ChIP-seq and ChIP analyses, we unveil that BET proteins directly promote the muscle atrophy program during cachexia. In addition, BET proteins are required to coordinate an IL6-dependent AMPK nuclear signaling pathway converging on FoxO3 transcription factor. Overall, these findings indicate that BET proteins may represent a promising therapeutic target in the management of cancer cachexia

Altered expression of antioxidant enzymes and autophagic proteins in transglutaminase 2 knockout mice

""Background. Transglutaminases (TGs) are ubiquitous calcium-dependent acyl-transferases, catalysing post-translational protein modifications. Among the family members, TG2 (or "tissue" transglutaminase) acts as a multifunctional protein regulating cell processes, including autophagy [1,2]. . TG2 is highly expressed in the nervous tissue and reportedly involved in neurodegenerative disorders [3]. Indeed, the pathophysiology of these diseases includes insoluble aggregate formation, and covalent cross-linking of pathogenic proteins by TG2 has been suggested. Another hallmark of neurodegeneration is dysregulated autophagy, thus making the role played by TG2 in this cellular process especially relevant. Interestingly, conditions promoting TG2 activity, such as low GTP and high calcium levels, associated with oxidative stress, occur in neurodegeneration. . The present study aims to clarify the role of TG2 in redox balance and autophagy. To this purpose, the expression levels of antioxidant enzymes and pro-autophagic proteins were investigated in various brain regions and liver of TG2-\\\/- mice. . . Materials and methods. Expression of antioxidant enzymes, namely superoxide dismutase 1 and 2 (SOD1, SOD2), catalase (CAT) and glutathione peroxidase 1 (GPX1), and autophagic proteins (Beclin1, LC3 and AMBRA1) were evaluated by Western blotting (WB) and immunohistochemistry in selected brain areas (neocortex, hippocampus, brainstem, and cerebellum) and liver of 12-month-old TG2-\\\/- and wild-type mice.. . Results. WB and immunohistochemical data reveal altered expression patterns of antioxidant enzymes in both liver and brain tissues. Of particular interest is the statistically significant decrease of CAT and SOD2 in the cerebellum and hippocampus of TG2-\\\/- mice, while unchanged levels of these proteins are detected in the neocortex and brainstem. In the knockout liver, even more dramatic reduction of CAT and SOD2 expression is found, while SOD1 is intriguingly upregulated. Concerning the effect of TG2 deletion on autophagy, Beclin1 is down-regulated in the neocortex and hippocampus of knockout mice.. . Conclusions. Overall, our data on TG2-\\\/- mice support the involvement of the transamidating enzyme in controlling redox balance of different organs, and in regulating autophagic flux [1-3]. The specific decrease in the peroxisomal enzyme CAT and in the mitochondrial protein SOD2 emphasizes the role of these organelles in oxidative stress management and their interplay in cell metabolism. Moreover, region-based differences in the effect of TG2 deletion may reflect multiple functions related to the organ, tissue and cell type.. "

Prenatal Exposure to BPA: The Effects on Hepatic Lipid Metabolism in Male and Female Rat Fetuses

Bisphenol A (BPA) is an organic chemical compound widely used for manufacturing plastics. BPA exposure originates principally from the diet, but it can also originate from dermal contact. In over 90% of individuals, including pregnant women, BPA is detectable in several body fluids. The effects of this exposure on the fetus are under active investigation in several research laboratories. The aim of our work was to study the impact of prenatal exposure to BPA in the liver of rat fetuses from a sex-dependent point of view. We particularly investigated the effects of prenatal BPA exposure on hepatic lipids because of their crucial role, not only for the liver, but also for the whole-body functions. Our results demonstrate that the liver of rat fetuses, in utero exposed to a very low dose of BPA (2.5 µg/kg/day), displays significant modulations with regard to proteins involved in cholesterol and fatty acid biosynthesis and trafficking. Moreover, an impact on inflammatory process has been observed. All these effects are dependent on sex, being observable only in female rat fetuses. In conclusion, this work demonstrates that maternal exposure to BPA compromises hepatic lipid metabolism in female offspring, and it also reveals the perspective impact of BPA on human health at doses currently considered safe

Alunos de idade avançada e o curso de licenciatura em química: dificuldades e motivações

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