The worldwide prevalence of latent autoimmune diabetes of adults among adult-onset diabetic individuals: a systematic review and meta-analysis

PURPOSE

The actual global burden of Latent Autoimmune Diabetes of Adults (LADA) remains unknown even though its prevalence is almost equal to the type 1 form of diabetes. Hence the present systematic review and meta-analysis were performed to estimate the prevalence of LADA among diabetic individuals using the studies published at global levels.

METHODS

A comprehensive literature revival was performed to identify articles on the prevalence of LADA published till 2023. The prevalence estimates were calculated using DerSimonian and Laird random-effects models with a heterogeneity measure by Cochrane Q and I2 statistics. Publication bias was assessed by the Doi plot and Luis Furuya-Kanamori asymmetry index (LFKindex). P < 0.05 was considered statistically significant.

RESULTS

The overall pooled prevalence of LADA obtained from a total of 51,725 diabetic individuals was found to be 8.9% (95%CI 7.5-10.4, P < 0.001) with a prevalence range of 2.3% in to 18.9% in United Arab Emirates and Bahrain respectively. Subgroup analysis of LADA in the context of the IDF geographic regions showed a higher prevalence in North America (13.5%), 9.5% in Middle East and North Africa, 9.4% in Africa, 9.2% in South East Asia, 8.3% in Western Pacific and the lowest prevalence of 7.0% in Europe.

CONCLUSION

The Meta-analysis revealed a worldwide prevalence of LADA as 8.9%, with the highest prevalence in Bahrain and the lowest in United Arab Emirates. Further, the higher prevalence in some IDF regions and the inconsistent association between socioeconomic status and LADA recommend more research in the future.

Synthesis and characterization of a Eu3+ -activated Ba2-x V2 O7 :xEu3+ phosphor using a hydrothermal method: a potential material for near-UV-WLED applications

Eu³⁺ -activated Ba₂ V₂ O₇ (Ba_2-x V₂ O₇ :xEu³⁺ ) phosphor materials were synthesized using a hydrothermal method and different concentrations of europium (x = 0.01, 0.02, 0.03, 0.04, and 0.05%). Phase purity, structural, morphological, optical, and luminescence characteristics of the as-synthesized phosphors were studied using powder X-ray diffraction (XRD), high resolution scanning electron microscopy, UV-visible spectroscopy, and fluorescence spectrometry. The recorded XRD patterns of the as-synthesized phosphors were indexed and predicted to be a triclinic structure. A cube-like morphology was obtained for the as-prepared samples. Broad absorption in the UV region from 200 nm to 380 nm was observed and the good transparency in the visible region at 400-800 nm originated from the [VO₄ ]^3- group charge transfer (CT) transition. The broad emission peak centred at 499 nm was due to the CT band of the [VO₄ ]^3- group. Also, a sharp peak observed at 613 nm was due to the electric dipole transition of ⁵ D₀ →⁷ F₂ of Eu³⁺ ions that occupied the lattice sites without inversion symmetry for all concentrations. The colour qualities of the as-prepared samples were calculated using Commission International de l'Eclairage coordinates. The colour-rending index (CRI) value was 86 for the Ba_1.97 V₂ O₇ :0.03Eu³⁺ phosphor. Furthermore, a WLED with a high CRI value of 95 was achieved by coupling the 3 W 356 nm near-UV light-emitting diode (LED) chip with the Ba_2-x V₂ O₇ :xEu³⁺ phosphor. These results suggested that the as-prepared phosphor materials are potential candidates for fabrication of near-UV chip excited WLEDs.

Quaternary variations in the structural assembly of N-acetylglucosamine-6-phosphate deacetylase from Pasteurella multocida

N-acetylglucosamine 6-phosphate deacetylase (NagA) catalyzes the conversion of N-acetylglucosamine-6-phosphate to glucosamine-6-phosphate in amino sugar catabolism. This conversion is an essential step in the catabolism of sialic acid in several pathogenic bacteria, including Pasteurella multocida, and thus NagA is identified as a potential drug target. Here, we report the unique structural features of NagA from P. multocida (PmNagA) resolved to 1.95 Å. PmNagA displays an altered quaternary architecture with unique interface interactions compared to its close homolog, the Escherichia coli NagA (EcNagA). We confirmed that the altered quaternary structure is not a crystallographic artifact using single particle electron cryo-microscopy. Analysis of the determined crystal structure reveals a set of hot-spot residues involved in novel interactions at the dimer-dimer interface. PmNagA binds to one Zn2+ ion in the active site and demonstrates kinetic parameters comparable to other bacterial homologs. Kinetic studies reveal that at high substrate concentrations (~10-fold the KM ), the tetrameric PmNagA displays hysteresis similar to its distant neighbor, the dimeric Staphylococcus aureus NagA (SaNagA). Our findings provide key information on structural and functional properties of NagA in P. multocida that could be utilized to design novel antibacterials.

Crystal structures of 6a,6b,7,11a-tetra-hydro-6H,9H-spiro-[chromeno[3',4':3,4]pyrrolo-[1,2-c]thia-zole-11,3'-indoline]-2',6-dione and 5'-methyl-6a,6b,7,11a-tetra-hydro-6H,9H-spiro-[chromeno[3',4':3,4]pyrrolo-[1,2-c]thia-zole-11,3'-indoline]-2',6-dione

The title compounds, (I) and (II), differ by the presence of a methyl group in position 5 on the 1H-indole-2-one ring of compound (II). There is also a significant difference in the conformation of the five-membered thia­zolidine ring in the two compounds.

The title compounds, C₂₀H₁₆N₂O₃S, (I), and C₂₁H₁₈N₂O₃S, (II), differ by the presence of a methyl group in position 5 on the 1H-indole-2-one ring of compound (II). The two compounds have a structural overlap r.m.s. deviation of 0.48 Å. There is a significant difference in the conformation of the thia­zolidine ring: it has a twisted conformation on the fused N—C bond in (I), but an envelope conformation in compound (II) with the S atom as the flap. The planar pyrrolidine ring of the indole ring system is normal to the mean plane of the five-membered pyrrolidine ring of the pyrrolo­thia­zole unit in both compounds, with dihedral angles of 88.71 (9) and 84.59 (8)°. The pyran rings in both structures have envelope conformations with the methyl­ene C atom adjacent to the C=O group as the flap. In both compounds, there is a short intra­molecular C—H⋯O contact present. In the crystal of (I), mol­ecules are linked by C—H⋯O hydrogen bonds forming chains propagating along the b-axis direction. The chains are linked by N—H⋯π inter­actions, forming layers parallel to (10). In the crystal of (II), mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers which are linked by C—H⋯O hydrogen bonds to form a three-dimensional structure.

Reflections on current Ayurveda research

The current development in modern biology partnered with technology, better understanding of genes, environment is beginning to allow predicting the state of the human body. Research in Modern science is in transitional state from reverse pharmacology to system approach. It's time for Ayurveda to undertake research deep in its own foundational theories and in its interface with modern science. The present environment, lifestyle and nutrition have drastically different from ancient times. There is a need to modernize Ayurveda and make it relevant and contextual in terms of personalized medicine where allopathic medicine is heading. Innovations based on advancements, new treatment regimen, therapeutic approaches are the current needs from Ayurveda to make an impact on global clinical practice. In India, the Ayurveda research needs commitment in leadership and good funding resources for its best run, and for true healthcare.

A strategy to identify a ketoreductase that preferentially synthesizes pharmaceutically relevant (S)-alcohols using whole-cell biotransformation

Introduction

Chemical industries are constantly in search of an expeditious and environmentally benign method for producing chiral synthons. Ketoreductases have been used as catalysts for enantioselective conversion of desired prochiral ketones to their corresponding alcohol. We chose reported promiscuous ketoreductases belonging to different protein families and expressed them in E. coli to evaluate their ability as whole-cell catalysts for obtaining chiral alcohol intermediates of pharmaceutical importance. Apart from establishing a method to produce high value (S)-specific alcohols that have not been evaluated before, we propose an in silico analysis procedure to predict product chirality.

Results

Six enzymes originating from Sulfolobus sulfotaricus, Zygosaccharomyces rouxii, Hansenula polymorpha, Corynebacterium sp. ST-10, Synechococcus sp. PCC 7942 and Bacillus sp. ECU0013 with reported efficient activity for dissimilar substrates are compared here to arrive at an optimal enzyme for the method. Whole–cell catalysis of ketone intermediates for drugs like Aprepitant, Sitagliptin and Dolastatin using E. coli over-expressing these enzymes yielded (S)-specific chiral alcohols. We explain this chiral specificity for the best-performing enzyme, i.e., Z. rouxii ketoreductase using in silico modelling and MD simulations. This rationale was applied to five additional ketones that are used in the synthesis of Crizotinib, MA-20565 (an antifungal agent), Sulopenem, Rivastigmine, Talampanel and Barnidipine and predicted the yield of (S) enantiomers. Experimental evaluation matched the in silico analysis wherein ~ 95% (S)-specific alcohol with a chemical yield of 23–79% was obtained through biotransformation. Further, the cofactor re-cycling was optimized by switching the carbon source from glucose to sorbitol that improved the chemical yield to 85–99%.

Conclusions

Here, we present a strategy to synthesize pharmaceutically relevant chiral alcohols by ketoreductases using a cofactor balanced whole-cell catalysis scheme that is useful for the industry. Based on the results obtained in these trials, Zygosaccharomyces rouxii ketoreductase was identified as a proficient enzyme to obtain (S)-specific alcohols from their respective ketones. The whole–cell catalyst when combined with nutrient modulation of using sorbitol as a carbon source helped obtain high enantiomeric and chemical yield.

Electronic supplementary material

The online version of this article (10.1186/s12934-018-1036-2) contains supplementary material, which is available to authorized users.

Crystal structures and kinetics of N-acetylneuraminate lyase from Fusobacterium nucleatum

N-Acetyl-D-neuraminic acid lyase (NanA) catalyzes the breakdown of sialic acid (Neu5Ac) to N-acetyl-D-mannosamine (ManNAc) and pyruvate. NanA plays a key role in Neu5Ac catabolism in many pathogenic and bacterial commensals where sialic acid is available as a carbon and nitrogen source. Several pathogens or commensals decorate their surfaces with sialic acids as a strategy to escape host innate immunity. Catabolism of sialic acid is key to a range of host-pathogen interactions. In this study, atomic resolution structures of NanA from Fusobacterium nucleatum (FnNanA) in ligand-free and ligand-bound forms are reported at 2.32 and 1.76 Å resolution, respectively. F. nucleatum is a Gram-negative pathogen that causes gingival and periodontal diseases in human hosts. Like other bacterial N-acetylneuraminate lyases, FnNanA also shares the triosephosphate isomerase (TIM)-barrel fold. As observed in other homologous enzymes, FnNanA forms a tetramer. In order to characterize the structure-function relationship, the steady-state kinetic parameters of the enzyme are also reported.

The Sodium Sialic Acid Symporter From Staphylococcus aureus Has Altered Substrate Specificity

Mammalian cell surfaces are decorated with complex glycoconjugates that terminate with negatively charged sialic acids. Commensal and pathogenic bacteria can use host-derived sialic acids for a competitive advantage, but require a functional sialic acid transporter to import the sugar into the cell. This work investigates the sodium sialic acid symporter (SiaT) from Staphylococcus aureus (SaSiaT). We demonstrate that SaSiaT rescues an Escherichia coli strain lacking its endogenous sialic acid transporter when grown on the sialic acids N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid (Neu5Gc). We then develop an expression, purification and detergent solubilization system for SaSiaT and demonstrate that the protein is largely monodisperse in solution with a stable monomeric oligomeric state. Binding studies reveal that SaSiaT has a higher affinity for Neu5Gc over Neu5Ac, which was unexpected and is not seen in another SiaT homolog. We develop a homology model and use comparative sequence analyses to identify substitutions in the substrate-binding site of SaSiaT that may explain the altered specificity. SaSiaT is shown to be electrogenic, and transport is dependent upon more than one Na⁺ ion for every sialic acid molecule. A functional sialic acid transporter is essential for the uptake and utilization of sialic acid in a range of pathogenic bacteria, and developing new inhibitors that target these transporters is a valid mechanism for inhibiting bacterial growth. By demonstrating a route to functional recombinant SaSiaT, and developing the in vivo and in vitro assay systems, our work underpins the design of inhibitors to this transporter.

Decreased expression of cell adhesion genes in cancer stem-like cells isolated from primary oral squamous cell carcinomas

The goal of this study was to isolate cancer stem-like cells marked by high expression of CD44, a putative cancer stem cell marker, from primary oral squamous cell carcinomas and identify distinctive gene expression patterns in these cells. From 1 October 2013 to 4 September 2015, 76 stage III-IV primary oral squamous cell carcinoma of the gingivobuccal sulcus were resected. In all, 13 tumours were analysed by immunohistochemistry to visualise CD44-expressing cells. Expression of CD44 within The Cancer Genome Atlas-Head and Neck Squamous Cell Carcinoma RNA-sequencing data was also assessed. Seventy resected tumours were dissociated into single cells and stained with antibodies to CD44 as well as CD45 and CD31 (together referred as Lineage/Lin). From 45 of these, CD44+Lin- and CD44-Lin- subpopulations were successfully isolated using fluorescence-activated cell sorting, and good-quality RNA was obtained from 14 such sorted pairs. Libraries from five pairs were sequenced and the results analysed using bioinformatics tools. Reverse transcription quantitative polymerase chain reaction was performed to experimentally validate the differential expression of selected candidate genes identified from the transcriptome sequencing in the same 5 and an additional 9 tumours. CD44 was expressed on the surface of poorly differentiated tumour cells, and within the The Cancer Genome Atlas-Head and Neck Squamous Cell Carcinoma samples, its messenger RNA levels were higher in tumours compared to normal. Transcriptomics revealed that 102 genes were upregulated and 85 genes were downregulated in CD44+Lin- compared to CD44-Lin- cells in at least 3 of the 5 tumours sequenced. The upregulated genes included those involved in immune regulation, while the downregulated genes were enriched for genes involved in cell adhesion. Decreased expression of PCDH18, MGP, SPARCL1 and KRTDAP was confirmed by reverse transcription quantitative polymerase chain reaction. Lower expression of the cell-cell adhesion molecule PCDH18 correlated with poorer overall survival in the The Cancer Genome Atlas-Head and Neck Squamous Cell Carcinoma data highlighting it as a potential negative prognostic factor in this cancer.

Automation aided optimization of cloning, expression and purification of enzymes of the bacterial sialic acid catabolic and sialylation pathways enzymes for structural studies

The process of obtaining a well-expressing, soluble and correctly folded constructs can be made easier and quicker by automating the optimization of cloning, expression and purification. While there are many semiautomated pipelines available for cloning, expression and purification, there is hardly any pipeline that involves complete automation. Here, we achieve complete automation of all the steps involved in cloning and in vivo expression screening. This is demonstrated using 18 genes involved in sialic acid catabolism and the surface sialylation pathway. Our main objective was to clone these genes into a His-tagged Gateway vector, followed by their small-scale expression optimization in vivo. The constructs that showed best soluble expression were then selected for purification studies and scaled up for crystallization studies. Our technique allowed us to quickly find conditions for producing significant quantities of soluble proteins in Escherichia coli, their large-scale purification and successful crystallization of a number of these proteins. The method can be implemented in other cases where one needs to screen a large number of constructs, clones and expression vectors for successful recombinant production of functional proteins.

"Just a spoonful of sugar...": import of sialic acid across bacterial cell membranes

Eukaryotic cell surfaces are decorated with a complex array of glycoconjugates that are usually capped with sialic acids, a large family of over 50 structurally distinct nine-carbon amino sugars, the most common member of which is N-acetylneuraminic acid. Once made available through the action of neuraminidases, bacterial pathogens and commensals utilise host-derived sialic acid by degrading it for energy or repurposing the sialic acid onto their own cell surface to camouflage the bacterium from the immune system. A functional sialic acid transporter has been shown to be essential for the uptake of sialic acid in a range of human bacterial pathogens and important for host colonisation and persistence. Here, we review the state-of-play in the field with respect to the molecular mechanisms by which these bio-nanomachines transport sialic acids across bacterial cell membranes.

One enzyme, many reactions: structural basis for the various reactions catalyzed by naphthalene 1,2-dioxygenase

Rieske nonheme iron oxygenases (ROs) are a well studied class of enzymes. Naphthalene 1,2-dioxygenase (NDO) is used as a model to study ROs. Previous work has shown how side-on binding of oxygen to the mononuclear iron provides this enzyme with the ability to catalyze stereospecific and regiospecific cis-dihydroxylation reactions. It has been well documented that ROs catalyze a variety of other reactions, including mono-oxygenation, desaturation, O- and N-dealkylation, sulfoxidation etc. NDO itself catalyzes a variety of these reactions. Structures of NDO in complex with a number of different substrates show that the orientation of the substrate in the active site controls not only the regiospecificity and stereospecificity, but also the type of reaction catalyzed. It is proposed that the mononuclear iron-activated dioxygen attacks the atoms of the substrate that are most proximal to it. The promiscuity of delivering two products (apparently by two different reactions) from the same substrate can be explained by the possible binding of the substrate in slightly different orientations aided by the observed flexibility of residues in the binding pocket.

Horse Liver Alcohol Dehydrogenase: Zinc Coordination and Catalysis

During catalysis by liver alcohol dehydrogenase (ADH), a water bound to the catalytic zinc is replaced by the oxygen of the substrates. The mechanism might involve a pentacoordinated zinc or a double-displacement reaction with participation by a nearby glutamate residue, as suggested by studies of human ADH3, yeast ADH1, and some other tetrameric ADHs. Zinc coordination and participation of water in the enzyme mechanism were investigated by X-ray crystallography. The apoenzyme and its complex with adenosine 5′-diphosphoribose have an open protein conformation with the catalytic zinc in one position, tetracoordinated by Cys-46, His-67, Cys-174, and a water molecule. The bidentate chelators 2,2′-bipyridine and 1,10-phenanthroline displace the water and form a pentacoordinated zinc. The enzyme–NADH complex has a closed conformation similar to that of ternary complexes with coenzyme and substrate analogues; the coordination of the catalytic zinc is similar to that found in the apoenzyme, except that a minor, alternative position for the catalytic zinc is ∼1.3 Å from the major position and closer to Glu-68, which could form the alternative coordination to the catalytic zinc. Complexes with NADH and N-1-methylhexylformamide or N-benzylformamide (or with NAD⁺ and fluoro alcohols) have the classical tetracoordinated zinc, and no water is bound to the zinc or the nicotinamide rings. The major forms of the enzyme in the mechanism have a tetracoordinated zinc, where the carboxylate group of Glu-68 could participate in the exchange of water and substrates on the zinc. Hydride transfer in the Michaelis complexes does not involve a nearby water.

Crystal structure of N-acetylmannosamine kinase from Fusobacterium nucleatum

Sialic acids comprise a varied group of nine-carbon amino sugars that are widely distributed among mammals and higher metazoans. Some human commensals and bacterial pathogens can scavenge sialic acids from their environment and degrade them for use as a carbon and nitrogen source. The enzyme N-acetylmannosamine kinase (NanK; EC 2.7.1.60) belongs to the transcriptional repressors, uncharacterized open reading frames and sugar kinases (ROK) superfamily. NanK catalyzes the second step of the sialic acid catabolic pathway, transferring a phosphate group from adenosine 5'-triphosphate to the C6 position of N-acetylmannosamine to generate N-acetylmannosamine 6-phosphate. The structure of NanK from Fusobacterium nucleatum was determined to 2.23 Å resolution by X-ray crystallography. Unlike other NanK enzymes and ROK family members, F. nucleatum NanK does not have a conserved zinc-binding site. In spite of the absence of the zinc-binding site, all of the major structural features of enzymatic activity are conserved.

Artificial sweeteners as a sugar substitute: Are they really safe?

Nonnutritive sweeteners (NNS) have become an important part of everyday life and are increasingly used nowadays in a variety of dietary and medicinal products. They provide fewer calories and far more intense sweetness than sugar-containing products and are used by a plethora of population subsets for varying objectives. Six of these agents (aspartame, saccharine, sucralose, neotame, acesulfame-K, and stevia) have previously received a generally recognized as safe status from the United States Food and Drug Administration, and two more (Swingle fruit extract and advantame) have been added in the recent years to this ever growing list. They are claimed to promote weight loss and deemed safe for consumption by diabetics; however, there is inconclusive evidence to support most of their uses and some recent studies even hint that these earlier established benefits regarding NNS use might not be true. There is a lack of properly designed randomized controlled studies to assess their efficacy in different populations, whereas observational studies often remain confounded due to reverse causality and often yield opposite findings. Pregnant and lactating women, children, diabetics, migraine, and epilepsy patients represent the susceptible population to the adverse effects of NNS-containing products and should use these products with utmost caution. The overall use of NNS remains controversial, and consumers should be amply informed about the potential risks of using them, based on current evidence-based dietary guidelines.

Structural and functional studies of ferredoxin and oxygenase components of 3-nitrotoluene dioxygenase from Diaphorobacter sp. strain DS2

3-nitrotoluene dioxygenase (3NTDO) from Diaphorobacter sp. strain DS2 catalyses the conversion of 3-nitrotoluene (3NT) into a mixture of 3- and 4-methylcatechols with release of nitrite. We report here, X-ray crystal structures of oxygenase and ferredoxin components of 3NTDO at 2.9 Å and 2.4 Å, respectively. The residues responsible for nitrite release in 3NTDO were further probed by four single and two double mutations in the catalytic site of α-subunit of the dioxygenase. Modification of Val 350 to Phe, Ile 204 to Ala, and Asn258 to Val by site directed mutagenesis resulted in inactive enzymes revealing the importance of these residues in catalysis. Docking studies of meta nitrotoluene to the active site of 3NTDO suggested possible orientations of binding that favor the formation of 3-methylcatechol (3MC) over 4-methylcatechol energetically. The electron transfer pathway from ferredoxin subunit to the active site of the oxygenase subunit is also proposed.

Developmental programming of polycystic ovary syndrome (PCOS): prenatal androgens establish pancreatic islet α/β cell ratio and subsequent insulin secretion

Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P = 0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P = 0.001), sustained into adolescence (P = 0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P = 0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P = 0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P = 0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells.

ID: 42: FACTORS ASSOCIATED WITH TREATMENT SEEKING IN VETERANS WITH LATE-ONSET PTSD

Background and Significance

Post-traumatic stress disorder (PTSD) is a chronic anxiety disorder with a lifetime prevalence of 6.8% in the general population and up to 30% among Vietnam War veterans. While presentation of PTSD is typically acute, delayed onset of PTSD (i.e., 6 months post trauma) is considered to be relatively rare. There is anecdotal evidence supporting reactivation of trauma memories and symptoms of PTSD among aging veterans who previously had no symptoms or treatment for PTSD. Clinically this type of presentation appears to be different from those presenting with symptoms earlier in life. It is unclear what might precipitate or reactivate these symptoms many years following trauma exposure. The Veterans Health Administration has a growing population of aging veterans exposed to combat during their military service. Current treatment guidelines provide limited guidance towards the management of late-onset PTSD. The prevalence of PTSD among OEF/OIF veterans is very high and as this cohort ages, we need to be better equipped to manage clinical changes seen across the lifespan. Understanding the clinical phenomenology, risk factors and potential biomarkers of this condition could pave the way for better screening methods and treatment interventions for clinicians.

Objective

To identify the characteristics and risk factors among late-life post-traumatic stress disorder (PTSD) treatment seekers.

Methods

The study is a retrospective chart review of patients diagnosed with PTSD after the age of 55 and a comparison group of veterans diagnosed with PTSD prior to the age of 55 in the VA Nebraska–Western Iowa Health Care System.

Results

Primary variables for analysis included demographic factors, military history, age at treatment seeking, PTSD Checklist (PCL) scores, PTSD treatment, recent stressors/reasons for seeking treatment (e.g., recent life changes, another trauma or reminder), and comorbid medical conditions.

Conclusions

A number of explanations have been proposed for the development of late-onset PTSD, including chronic inflammation and cumulative stress. We are conducting a separate study to determine whether plasma concentration of the inflammatory marker C-reactive protein (CRP) might help in predicting late-onset PTSD. Further studies are needed to evaluate the contributions of other factors (e.g., physical or cognitive decline, sleep disturbances, other traumas) to late-onset PTSD.

Abstract PD3-04: PAK-1 amplified breast cancer cell lines are preferentially sensitive to PAK inhibition with G-5555

The small GTP-binding proteins Rac1 and Cdc42 stimulate activity of the serine/threonine kinase p21-activated kinase-1 (PAK-1) to drive growth factor signaling networks and Ras-driven tumorigenesis. Genomic amplification and over-expression of PAK1 are prevalent in luminal breast cancer and correlate with poor clinical outcome. Here we use a novel and selective small molecule inhibitor, G-5555, of the group I PAKs (PAK1, 2, and 3) to evaluate the importance of PAK1 in promoting growth of PAK1 amplified breast cancer cells. Cell lines with amplification of PAK1 were found to be more sensitive to PAK1 inhibition than non-amplified cell lines. Additionally, reverse phase protein array (RPPA) was used to assess the effects of PAK1 inhibition on a wide range of signaling pathways in both amplified and non-amplified cell lines. Reduced levels of phosphorylation of MEK S298 was observed in all cell lines exposed to G-5555 irrespective of amplification status, consistent with PAK1 inhibition in these cell lines. However, modulation of this downstream PAK1 substrate did not correlate with inhibition of cell proliferation or induction of cell death. Cell lines that showed inhibition of proliferation in response to G-5555 also showed enhanced levels of cell death along with apoptosis. Moreover, G-5555 reduced tumor growth in the PAK1 amplified MDA-MB-175 xenograft tumor model. Finally, we compared the in vitro activity of G-5555 with palbociclib, a recently approved inhibitor of the cyclin-dependent kinases CDK4 and CDK6, in PAK1 amplified luminal breast cancer cell lines. Our data supports PAK1 as an attractive target in PAK1 amplified cells and tumors and suggests that inhibiting PAK1 rather than CDK4/6 in this context may be a more attractive therapeutic strategy.

Citation Format: Ong CC, Blackwood E, Jakubiak D, Daemen A, Ramaswamy S, Heise C, Schmidt M, Sanders L, Wilson TR, Huw L, Ndubaku C, Rudolph J, Hoeflich KP, Friedman L, O'Brien T. PAK-1 amplified breast cancer cell lines are preferentially sensitive to PAK inhibition with G-5555. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr PD3-04.

Mechanistic implications from structures of yeast alcohol dehydrogenase complexed with coenzyme and an alcohol

Yeast alcohol dehydrogenase I is a homotetramer of subunits with 347 amino acid residues, catalyzing the oxidation of alcohols using NAD(+) as coenzyme. A new X-ray structure was determined at 3.0 Å where both subunits of an asymmetric dimer bind coenzyme and trifluoroethanol. The tetramer is a pair of back-to-back dimers. Subunit A has a closed conformation and can represent a Michaelis complex with an appropriate geometry for hydride transfer between coenzyme and alcohol, with the oxygen of 2,2,2-trifluoroethanol ligated at 2.1 Å to the catalytic zinc in the classical tetrahedral coordination with Cys-43, Cys-153, and His-66. Subunit B has an open conformation, and the coenzyme interacts with amino acid residues from the coenzyme binding domain, but not with residues from the catalytic domain. Coenzyme appears to bind to and dissociate from the open conformation. The catalytic zinc in subunit B has an alternative, inverted coordination with Cys-43, Cys-153, His-66 and the carboxylate of Glu-67, while the oxygen of trifluoroethanol is 3.5 Å from the zinc. Subunit B may represent an intermediate in the mechanism after coenzyme and alcohol bind and before the conformation changes to the closed form and the alcohol oxygen binds to the zinc and displaces Glu-67.

First International Workshopson Provocative Questions (PQ) in Cancer Research, October-November 2014, New Delhi, Bengaluru, and Thiruvananthapuram, India

In 2011, the National Cancer Institute (NCI, USA) introduced the Provocative Questions (PQ) Initiative, a new approach allowing active researchers to define major unsolved or neglected problems in oncology unaddressed by existing funding. Last year, the U.S. NCI teamed up with the Indian Department of Biotechnology (DBT) to pilot the PQ approach in three cities in India. Workshop outcomes includedthe generation of fundable "PQs" (perplexing questions understudied by the international scientific community), as well as the identification of several non-PQ projects and research-related issues of importance to DBT and other Indian funding groups. The workshops clearly indicated the need to expand beyond crafting "PQs" when considering the best areas for research funding in international settings. Nonetheless, the first set of PQ workshops provided a forum to discuss key issues regarding cancer research in India, including the paucity of cancer research funding, and the lack of relevant human resource training and technology sharing platforms. Continued open debate between researchers, funders and policymakers will be essential to effectively strengthen the cancer research portfolio in India.

Genome sequencing of herb Tulsi (Ocimum tenuiflorum) unravels key genes behind its strong medicinal properties

BACKGROUND

Krishna Tulsi, a member of Lamiaceae family, is a herb well known for its spiritual, religious and medicinal importance in India. The common name of this plant is 'Tulsi' (or 'Tulasi' or 'Thulasi') and is considered sacred by Hindus. We present the draft genome of Ocimum tenuiflurum L (subtype Krishna Tulsi) in this report. The paired-end and mate-pair sequence libraries were generated for the whole genome sequenced with the Illumina Hiseq 1000, resulting in an assembled genome of 374 Mb, with a genome coverage of 61 % (612 Mb estimated genome size). We have also studied transcriptomes (RNA-Seq) of two subtypes of O. tenuiflorum, Krishna and Rama Tulsi and report the relative expression of genes in both the varieties.

RESULTS

The pathways leading to the production of medicinally-important specialized metabolites have been studied in detail, in relation to similar pathways in Arabidopsis thaliana and other plants. Expression levels of anthocyanin biosynthesis-related genes in leaf samples of Krishna Tulsi were observed to be relatively high, explaining the purple colouration of Krishna Tulsi leaves. The expression of six important genes identified from genome data were validated by performing q-RT-PCR in different tissues of five different species, which shows the high extent of urosolic acid-producing genes in young leaves of the Rama subtype. In addition, the presence of eugenol and ursolic acid, implied as potential drugs in the cure of many diseases including cancer was confirmed using mass spectrometry.

CONCLUSIONS

The availability of the whole genome of O.tenuiflorum and our sequence analysis suggests that small amino acid changes at the functional sites of genes involved in metabolite synthesis pathways confer special medicinal properties to this herb.

Active viscoelastic matter: from bacterial drag reduction to turbulent solids

A paradigm for internally driven matter is the active nematic liquid crystal, whereby the equations of a conventional nematic are supplemented by a minimal active stress that violates time-reversal symmetry. In practice, active fluids may have not only liquid-crystalline but also viscoelastic polymer degrees of freedom. Here we explore the resulting interplay by coupling an active nematic to a minimal model of polymer rheology. We find that adding a polymer can greatly increase the complexity of spontaneous flow, but can also have calming effects, thereby increasing the net throughput of spontaneous flow along a pipe (a "drag-reduction" effect). Remarkably, active turbulence can also arise after switching on activity in a sufficiently soft elastomeric solid.

In vivo crystallography at X-ray free-electron lasers: the next generation of structural biology?

The serendipitous discovery of the spontaneous growth of protein crystals inside cells has opened the field of crystallography to chemically unmodified samples directly available from their natural environment. On the one hand, through in vivo crystallography, protocols for protein crystal preparation can be highly simplified, although the technique suffers from difficulties in sampling, particularly in the extraction of the crystals from the cells partly due to their small sizes. On the other hand, the extremely intense X-ray pulses emerging from X-ray free-electron laser (XFEL) sources, along with the appearance of serial femtosecond crystallography (SFX) is a milestone for radiation damage-free protein structural studies but requires micrometre-size crystals. The combination of SFX with in vivo crystallography has the potential to boost the applicability of these techniques, eventually bringing the field to the point where in vitro sample manipulations will no longer be required, and direct imaging of the crystals from within the cells will be achievable. To fully appreciate the diverse aspects of sample characterization, handling and analysis, SFX experiments at the Japanese SPring-8 angstrom compact free-electron laser were scheduled on various types of in vivo grown crystals. The first experiments have demonstrated the feasibility of the approach and suggest that future in vivo crystallography applications at XFELs will be another alternative to nano-crystallography.

Time course and role of luteinizing hormone and follicle-stimulating hormone in the expansion of the Leydig cell population at the time of puberty in the rhesus monkey (Macaca mulatta)

In higher primates, development of the adult population of Leydig cells has received little attention. Here, the emergence of 3β-hydroxysteroid dehydrogenase (HSD3B) positive cells in the testis of the rhesus monkey was examined during spontaneous puberty, and correlated with S-phase labeling in the interstitium at this critical stage of development. In addition, the relative role of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in initiating the pubertal expansion of Leydig cells was studied by precociously stimulating the juvenile testis in vivo with pulsatile 11-day infusions of recombinant LH and FSH, either alone or in combination. At the time of castration, testes were immersion fixed in Bouin's, embedded in paraffin, and sectioned at 5 μm. Leydig cells/testis were enumerated using HSD3B as a Leydig cell marker. Leydig cell number per testis increased progressively during puberty to reach values in the adult approximately 10 fold greater than in early-pubertal animals. The rise in cell number was associated with an increase in nuclear diameter. That the pubertal expansion of Leydig cell number was driven primarily by the increase in LH secretion at this stage of development was suggested by the finding that precocious stimulation of mid-juvenile monkeys with LH, either alone or in combination with that of FSH, resulted in a 20-30 fold increase in the number of HSD3B-positive cells. Interestingly, precocious FSH stimulation, alone, also resulted in appearance of Leydig cells as indicated by the occasional HSD3B-positive cell in the interstitium. The nuclear diameter of these Leydig cells, however, was less than that of those generated in response to LH.

Yeast alcohol dehydrogenase structure and catalysis

Yeast (Saccharomyces cerevisiae) alcohol dehydrogenase I (ADH1) is the constitutive enzyme that reduces acetaldehyde to ethanol during the fermentation of glucose. ADH1 is a homotetramer of subunits with 347 amino acid residues. A structure for ADH1 was determined by X-ray crystallography at 2.4 Å resolution. The asymmetric unit contains four different subunits, arranged as similar dimers named AB and CD. The unit cell contains two different tetramers made up of "back-to-back" dimers, AB:AB and CD:CD. The A and C subunits in each dimer are structurally similar, with a closed conformation, bound coenzyme, and the oxygen of 2,2,2-trifluoroethanol ligated to the catalytic zinc in the classical tetrahedral coordination with Cys-43, Cys-153, and His-66. In contrast, the B and D subunits have an open conformation with no bound coenzyme, and the catalytic zinc has an alternative, inverted coordination with Cys-43, Cys-153, His-66, and the carboxylate of Glu-67. The asymmetry in the dimeric subunits of the tetramer provides two structures that appear to be relevant for the catalytic mechanism. The alternative coordination of the zinc may represent an intermediate in the mechanism of displacement of the zinc-bound water with alcohol or aldehyde substrates. Substitution of Glu-67 with Gln-67 decreases the catalytic efficiency by 100-fold. Previous studies of structural modeling, evolutionary relationships, substrate specificity, chemical modification, and site-directed mutagenesis are interpreted more fully with the three-dimensional structure.

Bacterial periplasmic sialic acid-binding proteins exhibit a conserved binding site

Sialic acids are a family of related nine-carbon sugar acids that play important roles in both eukaryotes and prokaryotes. These sialic acids are incorporated/decorated onto lipooligosaccharides as terminal sugars in multiple bacteria to evade the host immune system. Many pathogenic bacteria scavenge sialic acids from their host and use them for molecular mimicry. The first step of this process is the transport of sialic acid to the cytoplasm, which often takes place using a tripartite ATP-independent transport system consisting of a periplasmic binding protein and a membrane transporter. In this paper, the structural characterization of periplasmic binding proteins from the pathogenic bacteria Fusobacterium nucleatum, Pasteurella multocida and Vibrio cholerae and their thermodynamic characterization are reported. The binding affinities of several mutations in the Neu5Ac binding site of the Haemophilus influenzae protein are also reported. The structure and the thermodynamics of the binding of sugars suggest that all of these proteins have a very well conserved binding pocket and similar binding affinities. A significant conformational change occurs when these proteins bind the sugar. While the C1 carboxylate has been identified as the primary binding site, a second conserved hydrogen-bonding network is involved in the initiation and stabilization of the conformational states.

Expression, purification and substrate specificities of 3-nitrotoluene dioxygenase from Diaphorobacter sp. strain DS2

3-Nitotoluene dioxygenase (3-NTDO) is the first enzyme in the degradation pathway of 3-nitrotoluene (3-NT) by Diaphorobacter sp. strain DS2. The complete gene sequences of 3-NTDO were PCR amplified from genomic DNA of Diaphorobacter sp., cloned, sequenced and expressed. The 3-NTDO gene revealed a multi component structure having a reductase, a ferredoxin and two oxygenase subunits. Clones expressing the different subunits were constructed in pET21a expression vector system and overexpressed in E. coli BL21(DE3) host. Each subunit was individually purified separately to homogeneity. The active recombinant enzyme was reconstituted in vitro by mixing all three purified subunits. The reconstituted recombinant enzyme could catalyse biotransformations on a variety of organic aromatics.

Anti-inflammatory effect of certain dihydroxy flavones and the mechanisms involved

This study was designed to evaluate the anti-inflammatory action of four dihydroxy flavone derivatives; 3,3'- dihydroxy flavone, 5,6-dihydroxy flavone, 3,7-dihydroxy flavone and 6,3'-dihydroxy flavone and to further investigate the multiple cellular mechanisms underlying the anti-inflammatory effect of these compounds. The effect of dihydroxy flavones on acute inflammation was studied in rats employing carrageenan induced hind paw edema method. Further, the role of proinflammatory cytokines like TNF-α and IL-1β, cyclooxygenases (COX-1 and COX-2), and free radicals in the action of flavone derivatives was investigated using in vitro assays. All the four dihydroxy flavone derivatives exhibited time and dose dependent inhibition of carrageenan induced paw edema. In addition, the investigated compounds inhibited both the isoforms of cyclooxygenase and cytokines in a concentration dependent manner and also suppressed the release of reactive oxygen species. The anti-inflammatory effect of dihydroxy flavones may be through mechanisms that involve an interaction with cyclooxygenases, cytokines and reactive oxygen species.

Ovarian regulation of kisspeptin neurones in the arcuate nucleus of the rhesus monkey (macaca mulatta)

Tonic gonadotrophin secretion throughout the menstrual cycle is regulated by the negative-feedback actions of ovarian oestradiol (E₂) and progesterone. Although kisspeptin neurones in the arcuate nucleus (ARC) of the hypothalamus appear to play a major role in mediating these feedback actions of the steroids in nonprimate species, this issue has been less well studied in the monkey. In the present study, we used immunohistochemistry and in situ hybridisation to examine kisspeptin and KISS1 expression, respectively, in the mediobasal hypothalamus (MBH) of adult ovariectomised (OVX) rhesus monkeys. We also examined kisspeptin expression in the MBH of ovarian intact females, and the effect of E₂, progesterone and E₂ + progesterone replacement on KISS1 expression in OVX animals. Kisspeptin or KISS1 expressing neurones and pronounced kisspeptin fibres were readily identified throughout the ARC of ovariectomised monkeys but, on the other hand, in intact animals, kisspeptin cell bodies were small in size and number and only fine fibres were observed. Replacement of OVX monkeys with physiological levels of E₂, either alone or with luteal phase levels of progesterone, abolished KISS1 expression in the ARC. Interestingly, progesterone replacement alone for 14 days also resulted in a significant down-regulation of KISS1 expression. These findings support the view that, in primates, as in rodents and sheep, kisspeptin signalling in ARC neurones appears to play an important role in mediating the negative-feedback action of E₂ on gonadotrophin secretion, and also indicate the need to study further their regulation by progesterone.

The actin cortex as an active wetting layer

Using active gel theory we study theoretically the properties of the cortical actin layer of animal cells. The cortical layer is described as a non-equilibrium wetting film on the cell membrane. The actin density is approximately constant in the layer and jumps to zero at its edge. The layer thickness is determined by the ratio of the polymerization velocity and the depolymerization rate of actin.