A Proteomic Approach Identified TFEB as a Key Player in the Protective Action of Novel CB2R Bitopic Ligand FD22a against the Deleterious Effects Induced by ß-Amyloid in Glial Cells.

Neurodegenerative diseases (NDDs) are progressive multifactorial disorders of the nervous system sharing common pathogenic features, including intracellular misfolded protein aggregation, mitochondrial deficit, and inflammation. Taking into consideration the multifaceted nature of NDDs, development of multitarget-directed ligands (MTDLs) has evolved as an attractive therapeutic strategy. Compounds that target the cannabinoid receptor type II (CB2R) are rapidly emerging as novel effective MTDLs against common NDDs, such as Alzheimer's disease (AD). We recently developed the first CB2R bitopic/dualsteric ligand, namely FD22a, which revealed the ability to induce neuroprotection with fewer side effects. To explore the potential of FD22a as a multitarget drug for the treatment of NDDs, we investigated here its ability to prevent the toxic effect of ß-amyloid (Aß25-35 peptide) on human cellular models of neurodegeneration, such as microglia (HMC3) and glioblastoma (U87-MG) cell lines. Our results displayed that FD22a efficiently prevented Aß25-35 cytotoxic and proinflammatory effects in both cell lines and counteracted ß-amyloid-induced depression of autophagy in U87-MG cells. Notably, a quantitative proteomic analysis of U87-MG cells revealed that FD22a was able to potently stimulate the autophagy-lysosomal pathway (ALP) by activating its master transcriptional regulator TFEB, ultimately increasing the potential of this novel CB2R bitopic/dualsteric ligand as a multitarget drug for the treatment of NDDs.

Performance in Behavioral Testing in an Animal Model of Post-Surgical Hypoparathyroidism.

BACKGROUND: Hypoparathyroidism (HypoPT) is characterized by hypocalcemia and undetectable/inappropriately low PTH. Post-surgical HypoPT (PS-HypoPT) is the most common cause. Patients with PS-HypoPT present neuropsychological symptoms, probably due to the PTH deprivation in the central nervous system (CNS). However, these mechanisms are still not elucidated. The aim of this study was to evaluate the effects of PTH deprivation on CNS in an animal model of PS-HypoPT via a cognitive/behavioral assessment approach. METHODS: A surgical rat model of PS-HypoPT was obtained and treated with calcium to maintain normocalcemia. Twenty PS-HypoPT rats and twenty sham-operated controls (Crl) underwent behavioral testing in a Morris Water Maze (MWM), Open Field (OF), and Elevated Plus Maze (EPM). RESULTS: In the MWM, PTx rats showed a higher Escape Latency Time compared to Crl rats (p < 0.05); we observed a statistically significant improvement in the performance (day 1 to 8 p < 0.001), which was less pronounced in PTx group. In the OF test, the time and distance spent in the zone of interest were significantly lower in the PTx group compared with the Crl (p < 0.01 and p < 0.01). In the EPM experiment, the time spent in the close arm was significantly higher in the PTx group compared with the Crl (p < 0.01). CONCLUSIONS: This animal model of PS-HypoPT shows an impairment in spatial memory, which improved after training, and a marked anxiety-like behavior, resembling the condition of patients with PS-HypoPT. Further studies are needed to elucidate mechanisms.

Effect of Combined Levothyroxine (L-T4) and 3-Iodothyronamine (T1AM) Supplementation on Memory and Adult Hippocampal Neurogenesis in a Mouse Model of Hypothyroidism.

Mood alterations, anxiety, and cognitive impairments associated with adult-onset hypothyroidism often persist despite replacement treatment. In rodent models of hypothyroidism, replacement does not bring 3-iodothyronamine (T1AM) brain levels back to normal. T1AM is a thyroid hormone derivative with cognitive effects. Using a pharmacological hypothyroid mouse model, we investigated whether augmenting levothyroxine (L-T4) with T1AM improves behavioural correlates of depression, anxiety, and memory and has an effect on hippocampal neurogenesis. Hypothyroid mice showed impaired performance in the novel object recognition test as compared to euthyroid mice (discrimination index (DI): 0.02 ± 0.09 vs. 0.29 ± 0.06; t = 2.515, p = 0.02). L-T4 and L-T4+T1AM rescued memory (DI: 0.27 ± 0.08 and 0.34 ± 0.08, respectively), while T1AM had no effect (DI: -0.01 ± 0.10). Hypothyroidism reduced the number of neuroprogenitors in hippocampal neurogenic niches by 20%. L-T4 rescued the number of neuroprogenitors (mean diff = 106.9 ± 21.40, t = 4.99, pcorr = 0.003), while L-T4+T1AM produced a 30.61% rebound relative to euthyroid state (mean diff = 141.6 ± 31.91, t = 4.44, pcorr = 0.004). We performed qPCR analysis of 88 genes involved in neurotrophic signalling pathways and found an effect of treatment on the expression of Ngf, Kdr, Kit, L1cam, Ntf3, Mapk3, and Neurog2. Our data confirm that L-T4 is necessary and sufficient for recovering memory and hippocampal neurogenesis deficits associated with hypothyroidism, while we found no evidence to support the role of non-canonical TH signalling.

T1AM/TAAR1 System Reduces Inflammatory Response and ß-Amyloid Toxicity in Human Microglial HMC3 Cell Line.

Microglial dysfunction is one of the hallmarks and leading causes of common neurodegenerative diseases (NDDs), including Alzheimer's disease (AD) and Parkinson's disease (PD). All these pathologies are characterized by aberrant aggregation of disease-causing proteins in the brain, which can directly activate microglia, trigger microglia-mediated neuroinflammation, and increase oxidative stress. Inhibition of glial activation may represent a therapeutic target to alleviate neurodegeneration. Recently, 3-iodothyronamine (T1AM), an endogenous derivative of thyroid hormone (TH) able to interact directly with a specific GPCR known as trace amine-associated receptor 1 (TAAR1), gained interest for its ability to promote neuroprotection in several models. Nevertheless, T1AM's effects on microglial disfunction remain still elusive. In the present work we investigated whether T1AM could inhibit the inflammatory response of human HMC3 microglial cells to LPS/TNFα or ß-amyloid peptide 25-35 (Aß25-35) stimuli. The results of ELISA and qPCR assays revealed that T1AM was able to reduce microglia-mediated inflammatory response by inhibiting the release of proinflammatory factors, including IL-6, TNFα, NF-kB, MCP1, and MIP1, while promoting the release of anti-inflammatory mediators, such as IL-10. Notably, T1AM anti-inflammatory action in HMC3 cells turned out to be a TAAR1-mediated response, further increasing the relevance of the T1AM/TAAR1 system in the management of NDDs.

Iodotyrosines Are Biomarkers for Preclinical Stages of Iodine-Deficient Hypothyroidism in Dehal1-Knockout Mice.

Background: Iodine is required for the synthesis of thyroid hormone (TH), but its natural availability is limited. Dehalogenase1 (Dehal1) recycles iodine from mono- and diiodotyrosines (MIT, DIT) to sustain TH synthesis when iodine supplies are scarce, but its role in the dynamics of storage and conservation of iodine is unknown. Methods: Dehal1-knockout (Dehal1KO) mice were generated by gene trapping. The timing of expression and distribution was investigated by X-Gal staining and immunofluorescence using recombinant Dehal1-beta-galactosidase protein produced in fetuses and adult mice. Adult Dehal1KO and wild-type (Wt) animals were fed normal and iodine-deficient diets for 1 month, and plasma, urine, and tissues were isolated for analyses. TH status was monitored, including thyroxine, triiodothyronine, MIT, DIT, and urinary iodine concentration (UIC) using a novel liquid chromatography with tandem mass spectrometry method and the Sandell-Kolthoff (S-K) technique throughout the experimental period. Results: Dehal1 is highly expressed in the thyroid and is also present in the kidneys, liver, and, unexpectedly, the choroid plexus. In vivo transcription of Dehal1 was induced by iodine deficiency only in the thyroid tissue. Under normal iodine intake, Dehal1KO mice were euthyroid, but they showed negative iodine balance due to a continuous loss of iodotyrosines in the urine. Counterintuitively, the UIC of Dehal1KO mice is twofold higher than that of Wt mice, indicating that S-K measures both inorganic and organic iodine. Under iodine restriction, Dehal1KO mice rapidly develop profound hypothyroidism, while Wt mice remain euthyroid, suggesting reduced retention of iodine in the thyroids of Dehal1KO mice. Urinary and plasma iodotyrosines were continually elevated throughout the life cycles of Dehal1KO mice, including the neonatal period, when pups were still euthyroid. Conclusions: Plasma and urine iodotyrosine elevation occurs in Dehal1-deficient mice throughout life. Therefore, measurement of iodotyrosines predicts an eventual iodine shortage and development of hypothyroidism in the preclinical phase. The prompt establishment of hypothyroidism upon the start of iodine restriction suggests that Dehal1KO mice have low iodine reserves in their thyroid glands, pointing to defective capacity for iodine storage.

HPLC-MS-MS quantification of short-chain fatty acids actively secreted by probiotic strains.

Introduction: Short-chain fatty acids (SCFAs) are the main by-products of microbial fermentations occurring in the human intestine and are directly involved in the host's physiological balance. As impaired gut concentrations of acetic, propionic, and butyric acids are often associated with systemic disorders, the administration of SCFA-producing microorganisms has been suggested as attractive approach to solve symptoms related to SCFA deficiency. Methods: In this research, nine probiotic strains (Bacillus clausii NR, OC, SIN, and T, Bacillus coagulans ATCC 7050, Bifidobacterium breve DSM 16604, Limosilactobacillus reuteri DSM 17938, Lacticaseibacillus rhamnosus ATCC 53103, and Saccharomyces boulardii CNCM I-745) commonly included in commercial formulations were tested for their ability to secrete SCFAs by using an improved protocol in high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS-MS). Results: The developed method was highly sensitive and specific, showing excellent limits of detection and quantification of secreted SCFAs. All tested microorganisms were shown to secrete acetic acid, with only B. clausii and S. boulardii additionally able to produce propionic and butyric acids. Quantitative differences in the secretion of SCFAs were also evidenced. Discussion: The experimental approach described in this study may contribute to the characterization of probiotics as SCFA-producing organisms, a crucial stage toward their application to improve SCFA deficiency.

Empagliflozin inhibits excessive autophagy through the AMPK/GSK3ß signalling pathway in diabetic cardiomyopathy.

AIMS: Sodium-glucose cotransporter 2 inhibitors have beneficial effects on heart failure and cardiovascular mortality in diabetic and non-diabetic patients, with unclear mechanisms. Autophagy is a cardioprotective mechanism under acute stress conditions, but excessive autophagy accelerates myocardial cell death leading to autosis. We evaluated the protective role of empagliflozin (EMPA) against cardiac injury in murine diabetic cardiomyopathy. METHODS AND RESULTS: Male mice, rendered diabetics by one single intraperitoneal injection of streptozotocin and treated with EMPA (30 mg/kg/day), had fewer apoptotic cells (4.9 ± 2.1 vs. 1 ± 0.5 TUNEL-positive cells %, P < 0.05), less senescence (10.1 ± 2 vs. 7.9 ± 1.2 ß-gal positivity/tissue area, P < 0.05), fibrosis (0.2 ± 0.05 vs. 0.15 ± 0.06, P < 0.05 fibrotic area/tissue area), autophagy (7.9 ± 0.05 vs. 2.3 ± 0.6 fluorescence intensity/total area, P < 0.01), and connexin (Cx)-43 lateralization compared with diabetic mice. Proteomic analysis showed a down-regulation of the 5' adenosine monophosphate-activated protein kinase (AMPK) pathway and upstream activation of sirtuins in the heart of diabetic mice treated with EMPA compared with diabetic mice. Because sirtuin activation leads to the modulation of cardiomyogenic transcription factors, we analysed the DNA binding activity to serum response elements (SRE) of serum response factor (SRF) by electromobility shift assay. Compared with diabetic mice [0.5 ± 0.01 densitometric units (DU)], non-diabetic mice treated with EMPA (2.2 ± 0.01 DU, P < 0.01) and diabetic mice treated with EMPA (2.0 ± 0.1 DU, P < 0.01) significantly increased SRF binding activity to SRE, paralleled by increased cardiac actin expression (4.1 ± 0.1 vs. 2.2 ± 0.01 target protein/ß-actin ratio, P < 0.01). EMPA significantly reversed cardiac dysfunction on echocardiography in diabetic mice and inhibited excessive autophagy in high-glucose-treated cardiomyocytes by inhibiting the autophagy inducer glycogen synthase kinase 3 beta (GSK3ß), leading to reactivation of cardiomyogenic transcription factors. CONCLUSION: Taken together, our results describe a novel paradigm in which EMPA inhibits hyperactivation of autophagy through the AMPK/GSK3ß signalling pathway in the context of diabetes.

Congenital Hypothyroidism in Two Sudanese Families Harboring a Novel Iodotyrosine Deiodinase Mutation (IYD R279C).

Background: Congenital hypothyroidism due to defects in iodotyrosine deiodinase has variable phenotypes and can present as hypothyroid or with normal thyroid testing. Methods: Whole exome sequencing was performed in individuals from two families originating from different regions of Sudan. Mass spectrometry of urine and serum iodotyrosines was performed on subjects from both families. Results: A novel iodotyrosine deiodinase (IYD) mutation (c.835C>T; R279C) was identified in individuals from two Sudanese families inherited as autosomal recessive. The mutation was identified by multiple in silica analyses to likely be detrimental. Serum and urine monoiodotyrosine (MIT) and diiodotyrosine (DIT) were markedly elevated in the homozygous subjects. Conclusion: Measurement of serum and urine DIT and MIT was more sensitive than that of urine iodine or serum thyroid function tests to determine the effect of the IYD mutation.

Exogenous 3-Iodothyronamine (T1AM) Can Affect Phosphorylation of Proteins Involved on Signal Transduction Pathways in In Vitro Models of Brain Cell Lines, but These Effects Are Not Strengthened by Its Catabolite, 3-Iodothyroacetic Acid (TA1).

T1AM, a derivative of thyroid hormones, and its major catabolite, TA1, produce effects on memory acquisition in rodents. In the present study, we compared the effects of exogenous T1AM and TA1 on protein belonging to signal transduction pathways, assuming that TA1 may strengthen T1AM's effects in brain tissue. A hybrid line of cancer cells of mouse neuroblastoma and rat glioma (NG 108-15), as well as a human glioblastoma cell line (U-87 MG) were used. We first characterized the in vitro model by analyzing gene expression of proteins involved in the glutamatergic cascade and cellular uptake of T1AM and TA1. Then, cell viability, glucose consumption, and protein expression were assessed. Both cell lines expressed receptors implicated in glutamatergic pathway, namely Nmdar1, Glur2, and EphB2, but only U-87 MG cells expressed TAAR1. At pharmacological concentrations, T1AM was taken up and catabolized to TA1 and resulted in more cytotoxicity compared to TA1. The major effect, highlighted in both cell lines, albeit on different proteins involved in the glutamatergic signaling, was an increase in phosphorylation, exerted by T1AM but not reproduced by TA1. These findings indicate that, in our in vitro models, T1AM can affect proteins involved in the glutamatergic and other signaling pathways, but these effects are not strengthened by TA1.

Sex-related differential susceptibility to ponatinib cardiotoxicity and differential modulation of the Notch1 signalling pathway in a murine model.

Ponatinib (PON), a tyrosine kinase inhibitor approved in chronic myeloid leukaemia, has proven cardiovascular toxicity. We assessed mechanisms of sex-related PON-induced cardiotoxicity and identified rescue strategies in a murine model. PON+scrambled siRNA-treated male mice had a higher number of TUNEL-positive cells (%TdT+6.12 ± 0.17), higher percentage of SA-ß-gal-positive senescent cardiac area (%SA-ß-gal 1.41 ± 0.59) and a lower reactivity degree (RD) for the survival marker Bmi1 [Abs (OD) 5000 ± 703] compared to female (%TdT+3.75 ± 0.35; %SA-ß-gal 0.77 ± 0.02; Bmi1 [Abs (OD) 8567 ± 2173]. Proteomics analysis of cardiac tissue showed downstream activation of cell death in PON+siRNA scrambled compared to vehicle or PON+siRNA-Notch1-treated male mice. Upstream analysis showed beta-oestradiol activation, and downstream analysis showed activation of cell survival and inhibition of cell death in PON+scrambled siRNA compared to vehicle or PON+siRNA-Notch1-treated female mice. PON+scrambled siRNA-treated mice also had a downregulation of cardiac actin-more marked in males-and vessel density-more marked in females. Female hearts showed greater cardiac fibrosis than their male counterparts at baseline, with no significant change after PON treatment. PON+siRNA-scrambled mice had less fibrosis than vehicle or PON+siRNA-Notch1-treated mice. The left ventricular systolic dysfunction showed by PON+scrambled siRNA-treated mice (male %EF 28 ± 9; female %EF 36 ± 7) was reversed in both PON+siRNA-Notch1-treated male (%EF 53 ± 9) and female mice (%EF 52 ± 8). We report sex-related differential susceptibility and Notch1 modulation in PON-induced cardiotoxicity. This can help to identify biomarkers and potential mechanisms underlying sex-related differences in PON-induced cardiotoxicity.

Sodium-glucose cotransporter type 2 inhibitors prevent ponatinib-induced endothelial senescence and disfunction: A potential rescue strategy.

BACKGROUND: Ponatinib (PON), a third-generation tyrosine kinase inhibitor (TKI), has proven cardiovascular toxicity, with no known preventing agents usable to limit such side effect. Sodium-glucose cotransporter type 2 (SGLT2) inhibitors are a new class of glucose-lowering agents, featuring favorable cardiac and vascular effects. AIMS: We assessed the effects of the SGLT2 inhibitors empagliflozin (EMPA) and dapagliflozin (DAPA) on human aortic endothelial cells (HAECs) and underlying vasculo-protective mechanisms in an in vitro model of PON-induced endothelial toxicity. METHODS AND RESULTS: We exposed HAECs to PON or vehicle (DMSO) in the presence or absence of EMPA (100 and 500 nmol/L) or dapagliflozin (DAPA) for 0-48 h exposure times. Compared with vehicle, incubations of HAECs with PON significantly reduced cell viability (0.56 ± 0.11 vs 0.23 ± 0.05 absorbance units, p < 0.01), increased the number of senescent cells at ß-gal-assay (PON 9 ± 4 vs basal DMSO 3 ± 1 ß-Gal+ cells/field, p < 0.01), decreased tubulization in Matrigel (PON PON: 6 ± 1 vs basal DMSO 12 ± 1 tubuli number/field, p < 0.05) with a non-statistically significant trend of PON to decrease the number of autophagic cells at immunofluorescence assay and flow cytometry. EMPA reverted the effects of PON on cell viability (E 500 + PON 0.24 ± 0.05 vs PON 0.56 ± 0.11 absorbance units, p < 0.01) and induced autophagy (E 500 7 ± 4.3 vs basal DMSO 2.6 ± 2.3 mean fluorescence vs PON 2.6 ± 2.4 mean fluorescence, p < 0.05). EMPA and DAPA also reversed the effects of PON on cell senescence (E 500 + PON 4 ± 1 and DAPA 100 4 ± 2 vs PON 9 ± 4 ß-Gal+ cells/field, p < 0.01) and improved cell tubulization (E 500 + PON 21 ± 3 vs PON 6 ± 1 tubuli number/field, p < 0.05; DAPA 100 + PON 16 ± 2 vs PON 6 ± 1 tubuli number/field, p < 0.05). CONCLUSION: EMPA and DAPA attenuate the vasculo-toxic effect exerted by PON by reverting endothelial cell senescence and dysfunction. These findings support the design of clinical studies exploring the vasculo-protective effects of EMPA or DAPA on PON-induced vascular toxicity.

Mass spectrometry in the diagnosis of thyroid disease and in the study of thyroid hormone metabolism.

The importance of thyroid hormones in the regulation of development, growth, and energy metabolism is well known. Over the last decades, mass spectrometry has been extensively used to investigate thyroid hormone metabolism and to discover and characterize new molecules involved in thyroid hormones production, such as thyrotropin-releasing hormone. In the earlier period, the quantification methods, usually based on gas chromatography-mass spectrometry, were complicated and time consuming. They were mainly focused on basic research, and were not suitable for clinical diagnostics on a routine basis. The development of the modern mass spectrometers, mainly coupled to liquid chromatography, enabled simpler sample preparation procedures, and the accurate quantification of thyroid hormones, of their precursors, and of their metabolites in biological fluids, tissues, and cells became feasible. Nowadays, molecules of physiological and pathological interest can be assayed also for diagnostic purposes on a routine basis, and mass spectrometry is slowly entering the clinical laboratory. This review takes stock of the advancements in the field of thyroid metabolism that were carried out with mass spectrometry, with special focus on the use of this technique for the quantification of molecules involved in thyroid diseases.

A spatial multi-scale fluorescence microscopy toolbox discloses entry checkpoints of SARS-CoV-2 variants in Vero E6 cells.

We exploited a multi-scale microscopy imaging toolbox to address some major issues related to SARS-CoV-2 interactions with host cells. Our approach harnesses both conventional and super-resolution fluorescence microscopy and easily matches the spatial scale of single-virus/cell checkpoints. After its validation through the characterization of infected cells and virus morphology, we leveraged this toolbox to reveal subtle issues related to the entry phase of SARS-CoV-2 variants in Vero E6 cells. Our results show that in Vero E6 cells the B.1.1.7 strain (aka Alpha Variant of Concern) is associated with much faster kinetics of endocytic uptake compared to its ancestor B.1.177. Given the cell-entry scenario dominated by the endosomal "late pathway", the faster internalization of B.1.1.7 could be directly related to the N501Y mutation in the S protein, which is known to strengthen the binding of Spike receptor binding domain with ACE2. Remarkably, we also directly observed the central role of clathrin as a mediator of endocytosis in the late pathway of entry. In keeping with the clathrin-mediated endocytosis, we highlighted the non-raft membrane localization of ACE2. Overall, we believe that our fluorescence microscopy-based approach represents a fertile strategy to investigate the molecular features of SARS-CoV-2 interactions with cells.

Airways glutathione S-transferase omega-1 and its A140D polymorphism are associated with severity of inflammation and respiratory dysfunction in cystic fibrosis.

BACKGROUND: Glutathione S-transferase omega-1 (GSTO1-1) is a cytosolic enzyme that modulates the S-thiolation status of intracellular factors involved in cancer cell survival or in the inflammatory response. Studies focusing on chronic obstructive pulmonary disease (COPD) have demonstrated that GSTO1-1 is detectable in alveolar macrophages, airway epithelium and in the extracellular compartment, where its functions have not been completely understood. Moreover GSTO1-1 polymorphisms have been associated with an increased risk to develop COPD. Against this background, the aim of this study was to evaluate GSTO1-1 levels and its polymorphisms in cystic fibrosis (CF) patients. METHODS: Clinical samples from a previous study published by our groups were analyzed for GSTO1-1 levels and polymorphisms. For comparison, a model of lung inflammation in CFTR-knock out mice was also used. RESULTS: Our data document that soluble GSTO1-1 can be found in the airways of CF patients and correlates with inflammatory parameters such as neutrophilic elastase and the chemokine IL-8. A negative correlation was found between GSTO1-1 levels and the spirometric parameter FEV1 and the FEV1/FVC ratio. Additionally, the A140D polymorphism of GSTO1-1 was associated with lower levels of the antiinflammatory mediators PGE2 and 15(S)-HETE, and with lower values of the FEV1/FVC ratio in CF subjects with the homozygous CFTR ΔF508 mutation. CONCLUSIONS: Our data suggest that extracellular GSTO1-1 and its polymorphysms could have a biological and clinical significance in CF. Pathophysiological functions of GSTOs are far from being completely understood, and more studies are required to understand the role(s) of extracellular GSTO1-1 in inflamed tissues.

T1AM-TAAR1 signalling protects against OGD-induced synaptic dysfunction in the entorhinal cortex.

Abnormalities in thyroid hormones (TH) availability and/or metabolism have been hypothesized to contribute to Alzheimer's disease (AD) and to be a risk factor for stroke. Recently, 3-iodothyronamine (T1AM), an endogenous amine putatively derived from TH metabolism, gained interest for its ability to promote learning and memory in the mouse. Moreover, T1AM has been demonstrated to rescue the ß-Amyloid dependent LTP impairment in the entorhinal cortex (EC), a brain area crucially involved in learning and memory and early affected during AD. In the present work, we have investigated the effect of T1AM on ischemia-induced EC synaptic dysfunction. In EC brain slices exposed to oxygen-glucose deprivation (OGD), we demonstrated that the acute perfusion of T1AM (5 µM) was capable of preventing ischemia-induced synaptic depression and that this protective effect was mediated by the trace amine-associated receptor 1 (TAAR1). Moreover, we demonstrated that activation of the BDNF-TrkB signalling is required for T1AM action during ischemia. The protective effect of T1AM was more evident when using EC slices from transgenic mutant human APP (mhAPP mice) that are more vulnerable to the effect of OGD. Our results confirm that the TH derivative T1AM can rescue synaptic function after transient ischemia, an effect that was also observed in a Aß-enriched environment.

Is There a Crucial Link Between Vitamin D Status and Inflammatory Response in Patients With COVID-19?

Background: Hypovitaminosis D has been suggested to play a possible role in coronavirus disease 2019 (COVID-19) infection. Methods: The aim of this study is to analyze the relationship between vitamin D status and a biochemical panel of inflammatory markers in a cohort of patients with COVID-19. A secondary endpoint was to evaluate the correlation between 25OHD levels and the severity of the disease. Ninety-three consecutive patients with COVID-19-related pneumonia were evaluated from March to May 2020 in two hospital units in Pisa, in whom biochemical inflammatory markers, 25OHD levels, P/F ratio at nadir during hospitalization, and complete clinical data were available. Results: Sixty-five percent of patients presented hypovitaminosis D (25OHD ≤ 20 ng/ml) and showed significantly higher IL-6 [20.8 (10.9-45.6) vs. 12.9 (8.7-21.1) pg/ml, p = 0.02], CRP [10.7 (4.2-19.2) vs. 5.9 (1.6-8.1) mg/dl, p = 0.003], TNF-α [8.9 (6.0-14.8) vs. 4.4 (1.5-10.6) pg/ml, p = 0.01], D-dimer [0.53 (0.25-0.72) vs. 0.22 (0.17-0.35) mg/l, p = 0.002], and IL-10 [3.7 (1.8-6.9) vs. 2.3 (0.5-5.8) pg/ml, p = 0.03]. A significant inverse correlation was found between 25OHD and all these markers, even adjusted for age and sex. Hypovitaminosis D was prevalent in patients with severe ARDS, compared with the other groups (75% vs. 68% vs. 55%, p < 0.001), and 25OHD levels were lower in non-survivor patients. Conclusions: The relationship between 25OHD levels and inflammatory markers suggests that vitamin D status needs to be taken into account in the management of these patients. If vitamin D is a marker of poor prognosis or a possible risk factor with beneficial effects from supplementation, this still needs to be elucidated.

ACE2 in the Era of SARS-CoV-2: Controversies and Novel Perspectives.

Angiotensin-converting enzyme 2 (ACE2) is related to ACE but turned out to counteract several pathophysiological actions of ACE. ACE2 exerts antihypertensive and cardioprotective effects and reduces lung inflammation. ACE2 is subjected to extensive transcriptional and post-transcriptional modulation by epigenetic mechanisms and microRNAs. Also, ACE2 expression is regulated post-translationally by glycosylation, phosphorylation, and shedding from the plasma membrane. ACE2 protein is ubiquitous across mammalian tissues, prominently in the cardiovascular system, kidney, and intestine. ACE2 expression in the respiratory tract is of particular interest, in light of the discovery that ACE2 serves as the initial cellular target of severe acute respiratory syndrome (SARS)-coronaviruses, including the recent SARS-CoV2, responsible of the COronaVIrus Disease 2019 (COVID-19). Since the onset of the COVID-19 pandemic, an intense effort has been made to elucidate the biochemical determinants of SARS-CoV2-ACE2 interaction. It has been determined that SARS-CoV2 engages with ACE2 through its spike (S) protein, which consists of two subunits: S1, that mediates binding to the host receptor; S2, that induces fusion of the viral envelope with the host cell membrane and delivery of the viral genome. Owing to the role of ACE2 in SARS-CoV2 pathogenicity, it has been speculated that medical conditions, i.e., hypertension, and/or drugs, i.e., ACE inhibitors and angiotensin receptor blockers, known to influence ACE2 density could alter the fate of SARS-CoV-2 infection. The debate is still open and will only be solved when results of properly designed experimental and clinical investigations will be made public. An interesting observation is, however that, upon infection, ACE2 activity is reduced either by downregulation or by shedding. These events might precipitate the so-called "cytokine storm" that characterizes the most severe COVID-19 forms. As evidence accumulates, ACE2 appears a druggable target in the attempt to limit virus entry and replication. Strategies aimed at blocking ACE2 with antibodies, small molecules or peptides, or at neutralizing the virus by competitive binding with exogenously administered ACE2, are currently under investigations. In this review, we will present an overview of the state-of-the-art knowledge on ACE2 biochemistry and pathophysiology, outlining open issues in the context of COVID-19 disease and potential experimental and clinical developments.

An Update on Vitamin D Metabolism.

Vitamin D is a steroid hormone classically involved in the calcium metabolism and bone homeostasis. Recently, new and interesting aspects of vitamin D metabolism has been elucidated, namely the special role of the skin, the metabolic control of liver hydroxylase CYP2R1, the specificity of 1α-hydroxylase in different tissues and cell types and the genomic, non-genomic and epigenomic effects of vitamin D receptor, which will be addressed in the present review. Moreover, in the last decades, several extraskeletal effects which can be attributed to vitamin D have been shown. These beneficial effects will be here summarized, focusing on the immune system and cardiovascular system.

Sweat chloride assay by inductively coupled plasma mass spectrometry: a confirmation test for cystic fibrosis diagnosis.

The current guidelines for sweat chloride analysis identify the procedures for sweat collection, but not for chloride assay, which is usually performed by methods originally not aiming at the low concentrations of chloride found in sweat. To overcome this limitation, we set up, characterized, and adopted an original inductively coupled plasma mass spectrometry (ICP-MS) method for sweat chloride determination, which was designed for its easy use in a clinical laboratory. The method was linear in the range 8.5E-3 to 272.0E-3 mM, precision exhibited a relative standard deviation < 6%, and accuracy was in the range 99.7-103.8%. Limit of blank, limit of detection, and limit of quantitation were 2.1 mM, 3.2 mM, and 7.0 mM, respectively, which correspond to real concentrations injected into the mass spectrometer of 3.9E-3 mM for LOD and 8.5E-3 mM for LOQ. At first, the method was tested on 50 healthy volunteers who exhibited a mean chloride concentration of 15.7 mM (25-75th percentile 10.1-19.3 mM, range 2.8-37.4 mM); then, it was used to investigate two patients with suspected cystic fibrosis, who exhibited sweat chloride values of 65.6 mM and 81.2 mM, respectively. Moreover, the method was cross-validated by assaying 50 samples with chloride concentration values in the range 10-131 mM, by both ICP-MS and coulometric titration, which is the technology officially used in Tuscany for cystic fibrosis newborn screening. The reference analytical performances and the relatively low cost of ICP-MS, accompanied by the advantageous cost of a single sweat chloride assay, make this technology the best candidate to provide a top reference method for the quantification of chloride in sweat. The method that we propose was optimized and validated for sweat samples ≥ 75 mg, which is the minimum amount requested by the international protocols. However, the method sensitivity and, in addition, the possibility to reduce the sample dilution factor, make possible the quantification of chloride even in samples weighting < 75 mg that are discarded according to the current guidelines. Graphical abstract.