Molecular Effects of Chronic Exposure to Palmitate in Intestinal Organoids: A New Model to Study Obesity and Diabetes

Intestinal cell dysfunctions involved in obesity and associated diabetes could be correlated with impaired intestinal cell development. To date, the molecular mechanisms underlying these dysfunctions have been poorly investigated because of the lack of a good model for studying obesity. The main aim of this study was to investigate the effects of lipotoxicity on intestinal cell differentiation in small intestinal organoid platforms, which are used to analyze the regulation of cell differentiation. Mouse intestinal organoids were grown in the presence/absence of high palmitate concentrations (0.5 mM) for 48 h to simulate lipotoxicity. Palmitate treatment altered the expression of markers involved in the differentiation of enterocytes and goblet cells in the early (Hes1) and late (Muc2) phases of their development, respectively, and it modified enterocytes and goblet cell numbers. Furthermore, the expression of enteroendocrine cell progenitors (Ngn3) and I cells (CCK) markers was also impaired, as well as CCK-positive cell numbers and CCK secretion. Our data indicate, for the first time, that lipotoxicity simultaneously influences the differentiation of specific intestinal cell types in the gut: enterocytes, goblet cells and CCK cells. Through this study, we identified novel targets associated with molecular mechanisms affected by lipotoxicity that could be important for obesity and diabetes therapy.     

Mystery(n) Phenotypic Presentation in Europeans: Report of Three Further Novel Missense RNF213 Variants Leading to Severe Syndromic Forms of Moyamoya Angiopathy and Literature Review

Moyamoya angiopathy (MMA) is a rare cerebral vasculopathy in some cases occurring in children. Incidence is higher in East Asia, where the heterozygous p.Arg4810Lys variant in RNF213 (Mysterin) represents the major susceptibility factor. Rare variants in RNF213 have also been found in European MMA patients with incomplete penetrance and are today a recognized susceptibility factor for other cardiovascular disorders, from extracerebral artery stenosis to hypertension. By whole exome sequencing, we identified three rare and previously unreported missense variants of RNF213 in three children with early onset of bilateral MMA, and subsequently extended clinical and radiological investigations to their carrier relatives. Substitutions all involved highly conserved residues clustered in the C-terminal region of RNF213, mainly in the E3 ligase domain. Probands showed a de novo occurring variant, p.Phe4120Leu (family A), a maternally inherited heterozygous variant, p.Ser4118Cys (family B), and a novel heterozygous variant, p.Glu4867Lys, inherited from the mother, in whom it occurred de novo (family C). Patients from families A and C experienced transient hypertransaminasemia and stenosis of extracerebral arteries. Bilateral MMA was present in the proband’s carrier grandfather from family B. The proband from family C and her carrier mother both exhibited annular figurate erythema. Our data confirm that rare heterozygous variants in RNF213 cause MMA in Europeans as well as in East Asian populations, suggesting that substitutions close to positions 4118–4122 and 4867 of RNF213 could lead to a syndromic form of MMA showing elevated aminotransferases and extracerebral vascular involvement, with the possible association of peculiar skin manifestations.     

ILB®, a Low Molecular Weight Dextran Sulphate,Restores Glutamate Homeostasis,Amino Acid Metabolism and Neurocognitive Functions in a Rat Model of Severe Traumatic Brain Injury

In a previous study, we found that administration of ILB^®, a new low molecular weight dextran sulphate, significantly improved mitochondrial functions and energy metabolism, as well as decreased oxidative/nitrosative stress, of brain tissue of rats exposed to severe traumatic brain injury (sTBI), induced by the closed-head weight-drop model of diffused TBI. Using aliquots of deproteinized brain tissue of the same animals of this former study, we here determined the concentrations of 24 amino acids of control rats, untreated sTBI rats (sacrificed at 2 and 7 days post-injury) and sTBI rats receiving a subcutaneous ILB^® administration (at the dose levels of 1, 5 and 15 mg/kg b.w.) 30 min post-impact (sacrificed at 2 and 7 days post-injury). Additionally, in a different set of experiments, new groups of control rats, untreated sTBI rats and ILB^®-treated rats (administered 30 min after sTBI at the dose levels of 1 or 5 mg/kg b.w.) were studied for their neurocognitive functions (anxiety, locomotor capacities, short- and long-term memory) at 7 days after the induction of sTBI. Compared to untreated sTBI animals, ILB^® significantly decreased whole brain glutamate (normalizing the glutamate/glutamine ratio), glycine, serine and γ-aminobutyric acid. Furthermore, ILB^® administration restored arginine metabolism (preventing nitrosative stress), levels of amino acids involved in methylation reactions (methionine, L-cystathionine, S-adenosylhomocysteine), and N-acetylaspartate homeostasis. The macroscopic evidences of the beneficial effects on brain metabolism induced by ILB^® were the relevant improvement in neurocognitive functions of the group of animals treated with ILB^® 5 mg/kg b.w., compared to the marked cognitive decline measured in untreated sTBI animals. These results demonstrate that ILB^® administration 30 min after sTBI prevents glutamate excitotoxicity and normalizes levels of amino acids involved in crucial brain metabolic functions. The ameliorations of amino acid metabolism, mitochondrial functions and energy metabolism in ILB^®-treated rats exposed to sTBI produced significant improvement in neurocognitive functions, reinforcing the concept that ILB^® is a new effective therapeutic tool for the treatment of sTBI, worth being tested in the clinical setting.     

Mediterranean Diet and Parkinson’s Disease

Parkinson’s disease (PD) is an age-related neurodegenerative disorder, diagnosed on the basis of typical motor disturbances, but also characterized by the presence of non-motor symptoms, such as rapid eye movement (REM)-sleep behavior disorders, olfactory impairment, and constipation, which are often prodromal to the onset of the disease. PD is often associated with the presence of oxidative brain injury and chronic neuroinflammation, with infiltration and accumulation of peripheral immune cells that have been found in affected brain regions of PD patients. Recently, the role of the gut-brain axis in the pathogenesis of PD is getting more and more attention, and several pieces of evidence indicate alterations in the gut microbiota of PD-affected patients. Diet exerts a central role in defining the microbiota composition and different dietetic patterns can result in a higher or lower abundance of specific bacteria that, in turn, can affect gut permeability and express anti- or pro-inflammatory metabolites. In the present review, the effects of the Mediterranean diet in modulating both PD onset and its progression will be considered with a special focus on the antioxidant and anti-inflammatory properties of this dietetic regimen as well as on its effects on the microbiota composition.     

Bacterial DNAemia in Alzheimer’s Disease and Mild Cognitive Impairment: Association with Cognitive Decline,Plasma BDNF Levels,and Inflammatory Response

Microbial dysbiosis (MD) provokes gut barrier alterations and bacterial translocation in the bloodstream. The increased blood bacterial DNA (BB-DNA) may promote peripheral- and neuro-inflammation, contributing to cognitive impairment. MD also influences brain-derived neurotrophic factor (BDNF) production, whose alterations contribute to the etiopathogenesis of Alzheimer’s disease (AD). The purpose of this study is to measure BB-DNA in healthy elderly controls (EC), and in patients with mild cognitive impairment (MCI) and AD to explore the effect on plasma BDNF levels (pBDNF), the inflammatory response, and the association with cognitive decline during a two-year follow-up. Baseline BB-DNA and pBDNF were significantly higher in MCI and AD than in EC. BB-DNA was positively correlated with pBDNF in AD, plasma Tumor necrosis factor-alpha (TNF-α), and Interleukin-10 (IL-10) levels in MCI. AD patients with BB-DNA values above the 50th percentile had lower baseline Mini-Mental State Examination (MMSE). After a two-year follow-up, AD patients with the highest BB-DNA tertile had a worse cognitive decline, while higher BB-DNA levels were associated with higher TNF-α and lower IL-10 in MCI. Our study demonstrates that, in early AD, the higher the BB-DNA levels, the higher the pBDNF levels, suggesting a defensive attempt; BB-DNA seems to play a role in the AD severity/progression; in MCI, higher BB-DNA may trigger an increased inflammatory response.     

Downexpression of miR-200c-3p Contributes to Achalasia Disease by Targeting the PRKG1 Gene

Achalasia is an esophageal smooth muscle motility disorder with unknown pathogenesis. Taking into account our previous results on the downexpression of miR-200c-3p in tissues of patients with achalasia correlated with an increased expression of PRKG1, SULF1, and SYDE1 genes, our aim was to explore the unknown biological interaction between these genes and human miR-200c-3p and if this relation could unravel their functional role in the etiology of achalasia. To search for putative miR-200c-3p binding sites in the 3′-UTR of PRKG1, SULF1 and SYDE1, a bioinformatics tool was used. To test whether PRKG1, SULF1, and SYDE1 are targeted by miR-200c-3p, a dual-luciferase reporter assay and quantitative PCR on HEK293 and fibroblast cell lines were performed. To explore the biological correlation between PRKG1 and miR-200c-3p, an immunoblot analysis was carried out. The overexpression of miR-200c-3p reduced the luciferase activity in cells transfected with a luciferase reporter containing a fragment of the 3′-UTR regions of PRKG1, SULF1, and SYDE1 which included the miR-200c-3p seed sequence. The deletion of the miR-200c-3p seed sequence from the 3′-UTR fragments abrogated this reduction. A negative correlation between miR-200c-3p and PRKG1, SULF1, and SYDE1 expression levels was observed. Finally, a reduction of the endogenous level of PRKG1 in cells overexpressing miR-200c-3p was detected. Our study provides, for the first time, functional evidence about the PRKG1 gene as a direct target and SULF1 and SYDE1 as potential indirect substrates of miR-200c-3p and suggests the involvement of NO/cGMP/PKG signaling in the pathogenesis of achalasia.     

Differential Plasma Metabolites between High- and Low-Grade Meningioma Cases

Meningiomas (MGMs) are currently classified into grades I, II, and III. High-grade tumors are correlated with decreased survival rates and increased recurrence rates. The current grading classification is based on histological criteria and determined only after surgical tumor sampling. This study aimed to identify plasma metabolic alterations in meningiomas of different grades, which would aid surgeons in predefining the ideal surgical strategy. Plasma samples were collected from 51 patients with meningioma and classified into low-grade (LG) (grade I; n = 43), and high-grade (HG) samples (grade II, n = 5; grade III, n = 3). An untargeted metabolomic approach was used to analyze plasma metabolites. Statistical analyses were performed to select differential biomarkers among HG and LG groups. Metabolites were identified using tandem mass spectrometry along with database verification. Five and four differential biomarkers were identified for HG and LG meningiomas, respectively. To evaluate the potential of HG MGM metabolites to differentiate between HG and LG tumors, a receiving operating characteristic curve was constructed, which revealed an area under the curve of 95.7%. This indicates that the five HG MGM metabolites represent metabolic alterations that can differentiate between LG and HG meningiomas. These metabolites may indicate tumor grade even before the appearance of histological features.