Association between O-GlcNAc levels and platelet function in obese insulin-resistant subjects.

Obesity is an epidemic associated with platelet and vascular disorders. Platelet O-GlcNAcylation has been poorly studied in obese subjects. We aimed to evaluate O-linked N-acetyl-glucosamine (O-GlcNAc) levels and platelet activity in obese insulin-resistant (ObIR) subjects. Six healthy and six insulin-resistant obese subjects with a body mass index of 22.6 kg/m2 (SD ± 2.2) and 35.6 kg/m2 (SD ± 3.8), respectively, were included. Flow cytometry was used to measure markers of platelet activity, expression of P-selectin (CD62P antibody), glycoprotein IIb/IIIa (integrins αIIbß3 binding to PAC-1 antibody), and thrombin stimulation. O-GlcNAc was determined in the platelets of all test subjects by cytofluometry, intracellular calcium, percentage of platelet aggregation, and immunofluorescence microscopy and Western blot were used to assess O-GlcNAc and OGT (O-GlcNAc transferase) in platelets. Platelets from ObIR subjects had on average 221.4 nM intracellular calcium, 81.89% PAC-1, 22.85% CD62P, 57.48% OGT, and 66.62% O-GlcNAc, while platelets from healthy subjects had on average 719.2 nM intracellular calcium, 4.99% PAC-1, 3.17% CD62P, 18.38% OGT, and 23.41% O-GlcNAc. ObIR subjects showed lower platelet aggregation than healthy subjects, 13.83% and 54%, respectively. The results show that ObIR subjects have increased O-GlcNAc, and increased intraplatelet calcium associated with platelet hyperactivity and compared to healthy subjects, suggesting that changes in platelet protein O-GlcNAcylation and platelet activity might serve as a possible prognostic tool for insulin resistance, prediabetes and its progression to type 2 diabetes mellitus.

O-GlcNAcylation: Crosstalk between Hemostasis, Inflammation, and Cancer.

O-linked ß-N-acetylglucosamine (O-GlcNAc, O-GlcNAcylation) is a post-translational modification of serine/threonine residues of proteins. Alterations in O-GlcNAcylation have been implicated in several types of cancer, regulation of tumor progression, inflammation, and thrombosis through its interaction with signaling pathways. We aim to explore the relationship between O-GlcNAcylation and hemostasis, inflammation, and cancer, which could serve as potential prognostic tools or clinical predictions for cancer patients' healthcare and as an approach to combat cancer. We found that cancer is characterized by high glucose demand and consumption, a chronic inflammatory state, a state of hypercoagulability, and platelet hyperaggregability that favors thrombosis; the latter is a major cause of death in these patients. Furthermore, we review transcription factors and pathways associated with O-GlcNAcylation, thrombosis, inflammation, and cancer, such as the PI3K/Akt/c-Myc pathway, the nuclear factor kappa B pathway, and the PI3K/AKT/mTOR pathway. We also review infectious agents associated with cancer and chronic inflammation and potential inhibitors of cancer cell development. We conclude that it is necessary to approach both the diagnosis and treatment of cancer as a network in which multiple signaling pathways are integrated, and to search for a combination of potential drugs that regulate this signaling network.

Experimental Study of White Light Interferometry in Mach-Zehnder Interferometers Based on Standard Single Mode Fiber.

In this work, we experimentally analyzed and demonstrated the performance of an in-line Mach-Zehnder interferometer in the visible region, with an LED light source. The different waist diameter taper and asymmetric core-offset interferometers proposed used a single-mode fiber (SMF). The visibility achieved was V = 0.14 with an FSR of 23 nm for the taper MZI structure and visibilities of V = 0.3, V = 0.27, and V = 0.34 with FSRs of 23 nm, 17 nm, and 8 nm and separation lengths L of 2.5 cm, 4.0 cm, and 5.0 cm between the core-offset structure, respectively. The experimental investigation of the response to the temperature sensor yielded values from 50 °C to 300 °C; the sensitivity obtained was 3.53 a.u./°C, with R2 of 0.99769 and 1% every 1 °C in the transmission. For a range of 50 °C to 150 °C, 20.3 pm/°C with a R2 of 0.96604 was obtained.

Associations of Dynapenic Obesity and Sarcopenic Obesity with the Risk of Complications in COVID-19.

Ageing is associated with changes in body composition, such as low muscle mass (sarcopenia), decreased grip strength or physical function (dynapenia), and accumulation of fat mass. When the accumulation of fat mass synergistically accompanies low muscle mass or reduced grip strength, it results in sarcopenic obesity and dynapenic obesity, respectively. These types of obesity contribute to the increased risk of cardiovascular disease and mortality in the elderly, which could increase the damage caused by COVID-19. In this review, we associated factors that could generate a higher risk of COVID-19 complications in dynapenic obesity and sarcopenic obesity. For example, skeletal muscle regulates the expression of inflammatory cytokines and supports metabolic stress in pulmonary disease; hence, the presence of dynapenic obesity or sarcopenic obesity could be related to a poor prognosis in COVID-19 patients.

Analysis of SARS-CoV-2 mutations in Mexico, Belize, and isolated regions of Guatemala and its implication in the diagnosis.

The genomic sequences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide are publicly available and are derived from studies due to the increase in the number of cases. The importance of study of mutations is related to the possible virulence and diagnosis of SARS-CoV-2. To identify circulating mutations present in SARS-CoV-2 genomic sequences in Mexico, Belize, and Guatemala to find out if the same strain spread to the south, and analyze the specificity of the primers used for diagnosis in these samples. Twenty three complete SARS-CoV-2 genomic sequences, available in the GISAID database from May 8 to September 11, 2020 were analyzed and aligned versus the genomic sequence reported in Wuhan, China (NC_045512.2), using Clustal Omega. Open reading frames were translated using the ExPASy Translate Tool and UCSF Chimera (v.1.12) for amino acid substitutions analysis. Finally, the sequences were aligned versus primers used in the diagnosis of COVID-19. One hundred and eighty seven distinct variants were identified, of which 102 are missense, 66 synonymous and 19 noncoding. P4715L and P5828L substitutions in replicase polyprotein were found, as well as D614G in spike protein and L84S in ORF8 in Mexico, Belize, and Guatemala. The primers design by CDC of United States showed a positive E value. The genomic sequences of SARS-CoV-2 in Mexico, Belize, and Guatemala present similar mutations related to a virulent strain of greater infectivity, which could mean a greater capacity for inclusion in the host genome and be related to an increased spread of the virus in these countries, furthermore, its diagnosis would be affected.

Aggregation and Molecular Properties of ß-Glucosidase Isoform II in Chayote (Sechium edule).

The presence of isoforms of ß-glucosidase has been reported in some grasses such as sorghum, rice and maize. This work aims to extract and characterize isoform II in ß-glucosidase from S. edule. A crude extract was prepared without buffer solution and adjusted to pH 4.6. Contaminating proteins were precipitated at 4 °C for 24 h. The supernatant was purified by chromatography on carboxymethyl cellulose (CMC) column, molecular exclusion on Sephacryl S-200HR, and exchange anionic on QFF column. Electrophoretic analyzes revealed a purified enzyme with aggregating molecular complex on SDS-PAGE, Native-PAGE, and AU-PAGE. Twelve peptides fragments were identified by nano liquid chromatography-tandem mass spectrometry (nano LC-ESI-MS/MS), which presented as 61% identical to Cucurbita moschata ß-glucosidase and 55.74% identical to ß-glucosidase from Cucumis sativus, another Cucurbitaceous member. The relative masses which contained 39% hydrophobic amino acids ranged from 982.49 to 2,781.26. The enzyme showed a specificity to ß-d-glucose with a Km of 4.59 mM, a Vmax value of 104.3 µM∙min-1 and a kcat of 10,087 µM∙min-1 using p-nitrophenyl-ß-D-glucopyranoside. The presence of molecular aggregates can be attributed to non-polar amino acids. This property is not mediated by a ß-glucosidase aggregating factor (BGAF) as in grasses (maize and sorghum). The role of these aggregates is discussed.

Solvent-free synthesis of 6ß-phenylamino-cholestan-3ß,5α-diol and (25R)-6ß-phenylaminospirostan-3ß,5α-diol as potential antiproliferative agents.

In this paper is described a synthetic route to 6ß-phenylamino-cholestan-3ß,5α-diol and (25R)-6ß-phenylaminospirostan-3ß,5α-diol, starting from cholesterol and diosgenin, respectively. The products were obtained in two steps by epoxidation followed by aminolysis, through an environmentally friendly and solvent-free method mediated by SZ (sulfated zirconia) as catalyst. The use of SZ allows chemo- and regioselective ring opening of the 5,6α-epoxide during the aminolysis reaction eliminating the required separation of the epoxide mixture. The products obtained were spectroscopically characterized by 1H, PENDANT 13C NMR and HETCOR experiments, and complemented with FTIR-ATR and HRMS. The antiproliferative effect of the ß-aminoalcohols was evaluated on MCF-7 cells after 48h of incubation, by MTT and CVS assays. These methodologies showed that both compounds have antiproliferative activity, being more active the cholesterol analogue. Additionally, the cell images obtained by Harris' Hematoxylin and Eosin (H&E) staining protocol, evidenced formation of apoptotic bodies due to the presence of the obtained ß-aminoalcohols in a dose-dependent manner.

Protein C activation peptide inhibits the expression of ICAM-1, VCAM-1, and interleukin-8 induced by TNF-α in human dermal microvascular endothelial cells.

Activated protein C (APC) is generated from the cleavage of protein C by thrombin coupled to thrombomodulin and, subsequently, is released as protein C activation peptide (papC). The aim of this study was to evaluate the effect of papC on human dermal microvascular endothelial cells (HMEC-1), activated with 5 ng//mL TNF-α. Flow cytometry showed that papC inhibited the expression of VCAM-1 and ICAM-1, after activation with TNF-a. Similarly, RT-PCR analysis revealed that 2 and 4 pM papC inhibited the expression of VCAM-1 and IL-8 mRNA in TNF-α-treated HMEC-1. In addition, the expression of endothelial nitric oxide synthase(eNOS) increased in HMEC-1 treated with papC, compared to those without treatment. Furthermore, Jurkat cell adhesion to HMEC-1 induced by TNF-a was significantly inhibited after the addition of papC, compared to HMEC-1 without papC (p = 0.03). Finally, a control peptide analog to papC showed no effect on the expression of ICAM and VCAM on the surface of HMEC-1. In conclusion, our results suggest that papC exerts anti-inflammatory effects on endothelial cells.