Acceleration of protein glycation by oxidative stress and comparative role of antioxidant and protein glycation inhibitor.

Hyperglycemia in diabetes causes protein glycation that leads to oxidative stress, release of cytokines, and establishment of secondary complications such as neuropathy, retinopathy, and nephropathy. Several other metabolic disorders, stress, and inflammation generate free radicals and oxidative stress. It is essential to study whether oxidative stress independently enhances protein glycation leading to rapid establishment of secondary complications. Oxidative stress was experimentally induced using rotenone and Fenton reagent for in vivo and in vitro studies, respectively. Results showed significant increase in the rate of modification of BSA in the form of fructosamine and protein-bound carbonyls in the presence of fenton reagent. Circular dichroism studies revealed gross structural changes in the reduction of alpha helix structure and decreased protein surface charge was confirmed by zeta potential studies. Use of rotenone demonstrated enhanced AGE formation, ROS generation, and liver and kidney tissue glycation through fluorescence measurement. Similar findings were also observed in cell culture studies. Use of aminoguanidine, a protein glycation inhibitor, demonstrated reduction in these changes; however, a combination of aminoguanidine along with vitamin E demonstrated better amelioration. Thus, oxidative stress accelerates the process of protein glycation causing gross structural changes and tissue glycation in insulin-independent tissues. Use of antioxidants and protein glycation inhibitors in combination are more effective in preventing such changes and could be an effective therapeutic option for preventing establishment of secondary complications of diabetes.

Hierarchical Self-Assembly of Supramolecular Coordination Polymers Using Giant Metal-Organic Nanocapsules as Building Blocks.

Controlling the self-assembly of giant molecular building blocks into complex architectures with similar hierarchy to biological species remains a major challenge in supramolecular chemistry. Akin to protein structure, here we present the self-assembly of giant molecular nanocapsules into supramolecular coordination polymers with controlled hierarchy from primary to secondary and tertiary structures. First, we successfully prepared discrete nanocapsules (secondary structures) consisting of multicomponents, such as organic macrocycles and metal-based secondary building units (primary structures). Second, these nanocapsules can self-organize into various 2D and 3D supramolecular coordination polymers (tertiary structures) through coordination-driven assembly. The periphery 24 flexible alkyl chains and 24 metal ions available for potential coordination make these nanocapsules comparable to functionalized solid nanoparticles with non-specific binding sites at the surface and allow the nanocapsules to self-adjust their orientations and coordination modes to facilitate the self-assembly process. This study sheds light on the self-assembly of giant building units with complex molecular structures and opens up possibilities for the design of new hierarchical architectures with innovative properties and functions in many applications such as biomimics, biomedicine, and molecular devices.

Formation of Water Channels in the Crystalline Hydrates of Macrocyclic Compounds.

Crystalline hydrates of macrocyclic compounds such as pyroagllol[4]arenes (PgCs) and resorcin[4]arenes (RsCs) are rare owing to their lower water solubility. Functionalization of these macrocyclic compounds is an affordable way to enhance water solubility. However, functionalization also encounters the formation of multiple conformers and subsequent difficulty in purification of the product. Herein, four novel crystalline hydrates of functionalized PgCs and RsCs were synthesized. Formation of water channels and the effects of intermolecular interactions on the physical properties of these novel hydrates are discussed.

Synthesis of Protected Amino Hexitol Nucleosides as Building Blocks for Oligonucleotide Synthesis.

A new synthesis protocol for the preparation of hitherto unknown 1',5'-anhydro-4'-amino-trityl/MMTr hexitol nucleosides has been developed. Key steps in the synthesis of the pyrimidine analogues (U and C) include the regioselective d- allo-hexitol oxirane and 2',4'-anhydronucleoside ring opening by uracil and azide, respectively. A different strategy using a regioselective epoxide ring opening of d- gulo-oxirane, followed by a SN2 type of azidation reaction, has been adopted for the purine analogues (A and G). These compounds can be easily converted to 6'-phosphoramidites for the solid-phase synthesis of N4' → P6' phosphoramidates of amino hexitol nucleic acids (AHNA).

Controlled 2D Assembly of Nickel-Seamed Hexameric Pyrogallol[4]arene Nanocapsules.

The two-dimensional framework of nickel-seamed hexameric metal-organic nanocapsules has been synthesized by connecting the tailed hydroxyl groups of C-propan-3-ol pyrogallol[4]arene with adjacent hexameric capsules via nickel-hydroxyl coordination. In addition, functionalization of nanocapsules with multiple pyridine molecules at the capsule surface prevents them from assembling into hierarchical structures and leads to the formation of discrete nickel-seamed pyrogallol[4]arene nanocapsules. This work shows that surface functionalization of nanocapsules is an effective and innovative method of controlling the assembly of these nanometric building blocks.

Preparation of Magnesium-Seamed C-Alkylpyrogallol[4]arene Nanocapsules with Varying Chain Lengths.

Novel supramolecular nanocapsules based on metal-directed assembly have captured tremendous interest due to their applications in fields such as catalysis, selective gas adsorption, and biomedicine. Functionalization of metal-organic nanocapsules (MONCs) by using organic ligands with different pendant groups affords more complexity to the structure and may lead to novel properties. In this work, we report the solvothermal synthesis of a group of magnesium-based MONCs using C-alkylpyrogallol[4]arenes with varying alkyl chain lengths. The structures of these nanocapsules are characterized by single-crystal X-ray diffraction analysis. As expected, a progression in size of the nanocapsules is observed as the alkyl chain length increases. The effect of the chain length on the solubility of MONCs in water has been determined. This work shows the generality of the solvothermal approach for the synthesis of MONCs with different organic ligands and demonstrates that surface functionalization of MONCs may serve as an effective way to tailor their properties. The unique biocompatible nature and inherent large cavity of these magnesium-based MONCs make these nanocapsules promising for potential applications in biomedicine.

Cadiolides J-M, antibacterial polyphenyl butenolides from the Korean tunicate Pseudodistoma antinboja.

Activity-guided fractionations of the tunicate Pseudodistoma antinboja yielded four new compounds of the cadiolide class (cadiolides J-M, 1, 3-5) along with a known one (cadiolide H, 2). The structures were defined by spectroscopic methods including X-ray crystallographic analysis. These compounds were evaluated for their antibacterial activity and exhibited potent antibacterial activity against all of the drug resistant strains tested with MICs comparable to those of marketed drugs such as vancomycin and linezolid.

Process Development for Separation of Conformers from Derivatives of Resorcin[4]arenes and Pyrogallol[4]arenes.

Macrocyclic compounds, such as resorcin[4]arenes and pyrogallol[4]arenes, have proven to be useful building blocks in the construction of supramolecular organic frameworks (SOFs) because of their unique bowl-like shape and ability to interact through variety of intermolecular interactions. Herein, we report the synthesis and crystal structures of two functionalized resorcin[4]arenes and pyroagllol[4]arenes, 4-hydroxyphenylresorcin[4]arenes, and 4-hydroxyphenylpyrogallol[4]arenes. These phenyl-functionalized macrocycles usually have different conformers, such as cone, boat, chair, saddle, and diamond. The successful separation of predominant conformers from the crude product was carried out with solvent-extraction technique. The shape and molecular arrangement of these conformers in the individual crystal structure was verified with single-crystal X-ray diffraction studies.

Noria: A Highly Xe-Selective Nanoporous Organic Solid.

Separation of xenon and krypton is of industrial and environmental concern; the existing technologies use cryogenic distillation. Thus, a cost-effective, alternative technology for the separation of Xe and Kr and their capture from air is of significant importance. Herein, we report the selective Xe uptake in a crystalline porous organic oligomeric molecule, noria, and its structural analogue, PgC-noria, under ambient conditions. The selectivity of noria towards Xe arises from its tailored pore size and small cavities, which allows a directed non-bonding interaction of Xe atoms with a large number of carbon atoms of the noria molecular wheel in a confined space.

Selective CO2 Adsorption in a Supramolecular Organic Framework.

Considering the rapidly rising CO2 level, there is a constant need for versatile materials which can selectively adsorb CO2 at low cost. The quest for efficient sorptive materials is still on since the practical applications of conventional porous materials possess certain limitations. In that context, we designed, synthesized, and characterized two novel supramolecular organic frameworks based on C-pentylpyrogallol[4]arene (PgC5 ) with spacer molecules, such as 4,4'-bipyridine (bpy). Highly optimized and symmetric intermolecular hydrogen-bonding interactions between the main building blocks and comparatively weak van der Waals interactions between solvent molecules and PgC5 leads to the formation of robust extended frameworks, which withstand solvent evacuation from the crystal lattice. The evacuated framework shows excellent affinity for carbon dioxide over nitrogen and adsorbs ca. 3 wt % of CO2 at ambient temperature and pressure.

Anion- and Spacer-Directed Host-Guest Complexes of Bipyridine with Pyrogallol[4]arene.

New oval-shaped capsular and bilayer-type hydrogen-bonded arrangements of C-propyl-ol-pyrogallol[4]arene (PgC3-OH) with bipyridine-type spacer complexes are reported here. These complexes are engineered by virtue of derivatization of C-alkyl tails of pyrogallol[4]arene and the use of divergent spacer ligands. Complexes of PgC3-OH, PgC3-OH with bpy (4,4'-bipyridine) and PgC3-OH with bpa (1,2-bis(4-pyridyl)acetylene) have bilayer type arrangements; however, the use of hydrogen chloride causes protonation of bpy molecule, which is then entrapped flat within an offset oval-shaped dimeric hydrogen-bonded PgC3-OH nanocapsule. The presence of chloride anion in the crystal lattice controls the geometry of the resultant nanoassembly.

Monanchosterols A and B, bioactive bicyclo[4.3.1]steroids from a Korean sponge Monanchora sp.

Chemical investigation of a Korean marine sponge, Monanchora sp., led to the isolation of three new steroids (1-3). Compounds 1 and 2, designated as monanchosterols A and B, respectively, represent the first examples of steroids possessing the bicyclo[4.3.1] A/B ring system from a natural source. Compounds 1-3 were investigated for their anti-inflammatory activity by evaluating their inhibitory effects on the mRNA expression of IL-6, TNF-α, and COX-2 in the LPS-stimulated murine RAW264.7 macrophage cells. Compounds 2 and 3 exhibited significant inhibitory effects on the mRNA expression of IL-6 without notable cytotoxicity to the cells in a dose-dependent manner.

Anithiactins A-C, modified 2-phenylthiazoles from a mudflat-derived Streptomyces sp.

Intensive investigation of the chemical components of a Streptomyces sp. isolated from mudflat sediments collected on the southern coast of the Korean peninsula led to the isolation of three new compounds, anithiactins A-C (1-3). The chemical structures of anithiactins A and C were determined by interpretation of NMR data analyses, while the chemical structure of anithiactin B was established from a combination of NMR spectroscopic and crystallographic data analyses. The structure of anithiactin A was also confirmed by total synthesis. These three anithiactins displayed moderate acetylcholinesterase inhibitory activity with no significant cytotoxicity.

A Case Report of Simultaneous Intracranial Hemorrhage and Cerebral Venous Sinus Thrombosis in a Young Indian Male: Diagnostic and Therapeutic Challenges.

This case report discusses the intricate diagnostic and therapeutic challenges faced by a 23-year-old Indian male who presented with altered consciousness, a holo-cranial headache, right-sided hemiparesis, and subsequent neurological symptoms. The patient's dietary habits, leading to vitamin B12 and folic acid deficiencies resulting in hyperhomocysteinemia, along with binge alcohol drinking leading to dehydration, were identified as the main causes of cerebral venous sinus thrombosis (CVST) in this case. The case was complicated by an additional cerebral hemorrhage. The patient received a comprehensive treatment regimen involving antiepileptic medications, intravenous fluids, and anticoagulation therapy. A decline in the Glasgow Coma Scale score prompted further interventions. Collaborative decision-making, involving neurologists, neurosurgeons, and the patient's relatives, steered the treatment course, ultimately favoring continued medical management over decompression surgery. Notably, the patient exhibited remarkable progress in mobility, achieving the ability to walk with support by the end. This case report contributes valuable insights to the understanding of CVST, emphasizing the significance of nutritional considerations, especially in vegetarians, and underscoring the importance of thorough diagnostic evaluations in complex clinical scenarios.

Zinc-Dependent Histone Deacetylases in Lung Endothelial Pathobiology.

A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and, as such, provides a semi-selective barrier between the blood and the interstitial space. Compromise of the lung EC barrier due to inflammatory or toxic events may result in pulmonary edema, which is a cardinal feature of acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS). The EC functions are controlled, at least in part, via epigenetic mechanisms mediated by histone deacetylases (HDACs). Zinc-dependent HDACs represent the largest group of HDACs and are activated by Zn2+. Members of this HDAC group are involved in epigenetic regulation primarily by modifying the structure of chromatin upon removal of acetyl groups from histones. In addition, they can deacetylate many non-histone histone proteins, including those located in extranuclear compartments. Recently, the therapeutic potential of inhibiting zinc-dependent HDACs for EC barrier preservation has gained momentum. However, the role of specific HDAC subtypes in EC barrier regulation remains largely unknown. This review aims to provide an update on the role of zinc-dependent HDACs in endothelial dysfunction and its related diseases. We will broadly focus on biological contributions, signaling pathways and transcriptional roles of HDACs in endothelial pathobiology associated mainly with lung diseases, and we will discuss the potential of their inhibitors for lung injury prevention.

Serine/Threonine Protein Phosphatases 1 and 2A in Lung Endothelial Barrier Regulation.

Vascular barrier dysfunction is characterized by increased permeability and inflammation of endothelial cells (ECs), which are prominent features of acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and sepsis, and a major complication of the SARS-CoV-2 infection and COVID-19. Functional impairment of the EC barrier and accompanying inflammation arises due to microbial toxins and from white blood cells of the lung as part of a defensive action against pathogens, ischemia-reperfusion or blood product transfusions, and aspiration syndromes-based injury. A loss of barrier function results in the excessive movement of fluid and macromolecules from the vasculature into the interstitium and alveolae resulting in pulmonary edema and collapse of the architecture and function of the lungs, and eventually culminates in respiratory failure. Therefore, EC barrier integrity, which is heavily dependent on cytoskeletal elements (mainly actin filaments, microtubules (MTs), cell-matrix focal adhesions, and intercellular junctions) to maintain cellular contacts, is a critical requirement for the preservation of lung function. EC cytoskeletal remodeling is regulated, at least in part, by Ser/Thr phosphorylation/dephosphorylation of key cytoskeletal proteins. While a large body of literature describes the role of phosphorylation of cytoskeletal proteins on Ser/Thr residues in the context of EC barrier regulation, the role of Ser/Thr dephosphorylation catalyzed by Ser/Thr protein phosphatases (PPases) in EC barrier regulation is less documented. Ser/Thr PPases have been proposed to act as a counter-regulatory mechanism that preserves the EC barrier and opposes EC contraction. Despite the importance of PPases, our knowledge of the catalytic and regulatory subunits involved, as well as their cellular targets, is limited and under-appreciated. Therefore, the goal of this review is to discuss the role of Ser/Thr PPases in the regulation of lung EC cytoskeleton and permeability with special emphasis on the role of protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) as major mammalian Ser/Thr PPases. Importantly, we integrate the role of PPases with the structural dynamics of the cytoskeleton and signaling cascades that regulate endothelial cell permeability and inflammation.

Feasibility and Outcomes of Left Main to Branch Vessel PCI with Novel Tapered Coronary Stent in a Tertiary Care Centre: A Real World Experience.

OBJECTIVE: To assess the safety and efficacy of Novel tapered (BioMime™ Morph) sirolimus- eluting stent (SES) for left main PCI in a real-world scenario. BACKGROUND: Currently, no data is available on clinical usefulness of tapered ultrathin stents in left main PCI. METHODS: This was a prospective, non-randomised, single centre study carried out between February 2018 and May 2020 at a tertiary cardiac care centre in southern India. The study included patients treated with BioMime Morph tapered stent for distal de novo LMB lesion or ostial LAD/LCX lesions with significant size disparity between reference segments based on the eligibility criteria. Primary endpoint of the study was the cumulative incidence of major adverse cardiovascular events (MACE) composed of cardiac death, myocardial infarction, and clinically driven target-lesion revascularisation at follow-up. RESULTS: A total of 41 patients (average age of 54.83±9.81 years) were included in the study. Average SS-2 score was 23.17±5.42. Majority of the lesions (n=31; 75.61%) were of medina class (0.1.0). Provisional single stent strategy was adopted for treatment of LMB lesions. TIMI flow-3 was achieved in 40 patients (97.56%). Median clinical follow-up was 20 months (range 6-34 months). There was no periprocedural complication or MACE during follow-up. CONCLUSION: Tapered stents may be an acceptable alternative for LM intervention in an anatomical subset of patients with tapered vessels.

In vitro model using cytokine cocktail to evaluate apoptosis in Min6 pancreatic beta cells.

INTRODUCTION: Development of therapy options for treatment of type 1 diabetes mellitus is hampered by non-availability of appropriate experimental models that can exactly mimic the in vivo situation. Apoptosis of beta cells by T cells and cytokine action leads to loss of beta cells. We propose a simple and elegant model using cytokine cocktail of TNF-α, IFN-γ and IL-1ß, the major cytokines responsible for apoptosis in Min6 beta cell line. METHODS: A cocktail of TNF-α, IFN-γ and IL-1ß was used to induce apoptosis in Min6 beta cell line. Apoptosis was assessed by flow cytometry using CytoFLEX (Beckman Coulter). The destruction of beta cells is through production of nitric oxide (NO), oxidative stress and change in mitochondrial membrane permeability. NO was measured using Griess reagent. Oxidative stress was assessed using 2',7'-dichlorofluorescein diacetate, a cell-permeable fluorogenic dye and mitochondrial membrane potential was determined on the basis of retention of rhodamine 123 using flow cytometer. RESULTS AND DISCUSSION: Very low concentration of the cocktail viz. TNF-α 25 ng/ml, IFN-γ 25 ng/ml and IL-1ß 50 ng/ml has demonstrated effective early and late apoptosis in as short a time period as 6 h. The experimental model used demonstrated 1.5 fold higher production of NO, 1.2 fold increased oxidative stress and lower mitochondrial membrane potential as compared to the positive control used. Hence the above model can be easily used for assessment and screening of drugs that can prevent apoptosis of beta cells and stop progression of type 1 diabetes.

Profile of coronary artery disease in indian rural youth (< 35 yrs).

AIMS: To study the risk factors, clinical and angiographic profile of Indian rural youth (under 35yrs) presenting with Premature Coronary Artery Disease (PCAD). SUBJECTS: and Methods: The PCAD registry had 1628 patients who were aged below 35 years, of which 681 patients satisfied the entry criteria. The data was analysed by statistical software R version 3.5.0. RESULTS: The study enrolled 681 patients after satisfying the entry criteria. The mean age of patients was 30.85 years. There were 405 (59.5%) aged between 30 and 35 yrs, 205 (30.1%) between 25 and 30 yrs, 64 (9.4%) between 20 and 25 yrs and 7 (1.0%) were aged less than 20 yrs. Majority of them were males, 617 (90.6%). Nearly 411 (60.4%) were smokers, 56patients (8.2%) were diabetics and 97 (14.2%) were hypertensives. Around 441 (64.8%) patients had low HDL cholesterol levels and 218 (32.0%) had elevated triglyceride levels. Abdominal obesity was seen in 443 (65.1%) patients. Most common clinical presentation was ST elevation myocardial infarction (STEMI) seen in 536 (78.7%) patients. Around 40% patients had recanalized/non obstructive/thrombotic/normal coronaries on coronary angiogram. CONCLUSIONS: Conventional risk factors such as smoking, low HDL levels and abdominal obesity play a major role in the causation of premature coronary artery disease among the rural youth. Thrombotic milieu in the coronaries was commonly noted in coronary angiograms. Lack of awareness, combined with urbanisation of rural lifestyle could be responsible for increasing incidence of premature coronary artery disease in rural youth.

Early metabolic changes in the gut leads to higher expression of intestinal alpha glucosidase and thereby causes enhanced postprandial spikes.

AIMS: Prediabetes manifests several years earlier, before it progresses to diabetes. It is essential to track the earliest metabolic changes occurring in the prediabetic state and to understand the precise mechanism of how diabetes is initiated. MAIN METHODS: Alpha glucosidase was isolated from rat intestine and assayed using maltose as substrate. In vitro glycation of the enzyme was studied using varying fructose content through measurement of fructosamine, general and specific fluorescence. In vivo experiments were carried out through feed of 4 g fructose per day. Protein expression was studied using western blot and mRNA expression using RT-PCR method. KEY FINDINGS: Fructose inhibits alpha glucosidase to the extent of 48.97% in 4 h at 2.5 M concentration. In vivo studies demonstrated an inhibition of 56.96% in three days. Activity was found to rise by seven days and normalized by 10 days. Protein expression was found to increase by 10.56 fold and SI mRNA by 41.84 fold on 10 days of fructose feed. Long term fructose feed for 60 days demonstrated increase in alpha glucosidase activity by 2.12 fold and increase in postprandial glucose spike. SIGNIFICANCE: Glycation of alpha glucosidase causes inhibition of the enzyme activity leading to compensation through higher protein expression. Long term fructose feed leads to more than two fold increase in enzyme activity causing postprandial spikes and ultimately manifesting as diabetes mellitus.