Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

A full account of our efforts toward an asymmetric redox bicycloisomerization reaction is presented in this article. Cyclopentadienylruthenium (CpRu) complexes containing tethered chiral sulfoxides were synthesized via an oxidative [3 + 2] cycloaddition reaction between an alkyne and an allylruthenium complex. Sulfoxide complex 1 containing a p-anisole moiety on its sulfoxide proved to be the most efficient and selective catalyst for the asymmetric redox bicycloisomerization of 1,6- and 1,7-enynes. This complex was used to synthesize a broad array of [3.1.0] and [4.1.0] bicycles. Sulfonamide- and phosphoramidate-containing products could be deprotected under reducing conditions. Catalysis performed with enantiomerically enriched propargyl alcohols revealed a matched/mismatched effect that was strongly dependent on the nature of the solvent.

Capture and Recycling of Sortase A through Site-Specific Labeling with Lithocholic Acid

Enzyme-mediated protein modification often requires large amounts of biocatalyst, adding significant costs to the process and limiting industrial applications. Herein, we demonstrate a scalable and straightforward strategy for the efficient capture and recycling of enzymes using a small-molecule affinity tag. A proline variant of an evolved sortase A (SrtA 7M) was N-terminally labeled with lithocholic acid (LA)-an inexpensive bile acid that exhibits strong binding to β-cyclodextrin (βCD). Capture and recycling of the LA-Pro-SrtA 7M conjugate was achieved using βCD-modified sepharose resin. The LA-Pro-SrtA 7M conjugate retained full enzymatic activity, even after multiple rounds of recycling.

Mechanism of Assembly of a Substrate Transfer Complex during Tail-anchored Protein Targeting

Tail-anchored (TA) proteins, defined as having a single transmembrane helix at their C terminus, are post-translationally targeted to the endoplasmic reticulum membrane by the guided entry of TA proteins (GET) pathway. In yeast, the handover of TA substrates is mediated by the heterotetrameric Get4/Get5 complex (Get4/5), which tethers the co-chaperone Sgt2 to the targeting factor, the Get3 ATPase. Binding of Get4/5 to Get3 is critical for efficient TA targeting; however, questions remain about the formation of the Get3·Get4/5 complex. Here we report crystal structures of a Get3·Get4/5 complex from Saccharomyces cerevisiae at 2.8 and 6.0 Å that reveal a novel interface between Get3 and Get4 dominated by electrostatic interactions. Kinetic and mutational analyses strongly suggest that these structures represent an on-pathway intermediate that rapidly assembles and then rearranges to the final Get3·Get4/5 complex. Furthermore, we provide evidence that the Get3·Get4/5 complex is dominated by a single Get4/5 heterotetramer bound to one monomer of a Get3 dimer, uncovering an intriguing asymmetry in the Get4/5 heterotetramer upon Get3 binding. Ultrafast diffusion-limited electrostatically driven Get3·Get4/5 association enables Get4/5 to rapidly sample and capture Get3 at different stages of the GET pathway.

Correlation of plasma nitrite/nitrate levels and inducible nitric oxide gene expression among women with cervical abnormalities and cancer

Cervical cancer is caused by infection with high risk human papillomavirus (HR-HPV). Inducible nitric oxide synthase (iNOS), a soluble factor involved in chronic inflammation, may modulate cervical cancer risk among HPV infected women. The aim of the study was to measure and correlate plasma nitrite/nitrate levels with tissue specific expression of iNOS mRNA among women with different grades of cervical lesions and cervical cancer. Tissue biopsy and plasma specimens were collected from 120 women with cervical neoplasia or cancer (ASCUS, LSIL, HSIL and invasive cancer) and 35 women without cervical abnormalities. Inducible nitric oxide synthase (iNOS) mRNA from biopsy and plasma nitrite/nitrate levels of the same study subjects were measured. Single nucleotide polymorphism (SNP) analysis was performed on the promoter region and Ser608Leu (rs2297518) in exon 16 of the iNOS gene. Differences in iNOS gene expression and plasma nitrite/nitrate levels were compared across disease stage using linear and logistic regression analysis. Compared to normal controls, women diagnosed with HSIL or invasive cancer had a significantly higher concentration of plasma nitrite/nitrate and a higher median fold-change in iNOS mRNA gene expression. Genotyping of the promoter region showed three different variations: A pentanucleotide repeat (CCTTT) n, -1026T > G (rs2779249) and a novel variant -1153T > A. These variants were associated with increased levels of plasma nitrite/nitrate across all disease stages. The higher expression of iNOS mRNA and plasma nitrite/nitrate among women with pre-cancerous lesions suggests a role for nitric oxide in the natural history of cervical cancer.

Inflammation and tuberculosis: host-directed therapies

Tuberculosis (TB) is an airborne infectious disease that kills almost two million individuals every year. Multidrug-resistant (MDR) TB is caused by strains of Mycobacterium tuberculosis (M. tb) resistant to isoniazid and rifampin, the backbone of first-line antitubercular treatment. MDR TB affects an estimated 500,000 new patients annually. Genetic analysis of drug-resistant MDR-TB showed that airborne transmission of undetected and untreated strains played a major role in disease outbreaks. The need for new TB vaccines and faster diagnostics, as well as the development of new drugs, has recently been highlighted. The major problem in terms of current TB research and clinical demands is the increasing number of cases of extensively drug-resistant and 'treatment-refractory' TB. An emerging scenario of adjunct host-directed therapies is intended to target pulmonary TB where inflammatory processes can be deleterious and lead to immune exhaustion. 'Target-organ-saving' strategies may be warranted to prevent damage to infected tissues and achieve focused, clinically relevant and long-lasting anti-M. tb cellular immune responses. Candidates for such interventions may be biological agents or already approved drugs that can be 're-purposed' to interfere with biologically relevant cellular checkpoints. Here, we review current concepts of inflammation in TB disease and discuss candidate pathways for host-directed therapies to achieve better clinical outcomes.

The defect of both angiogenesis and lymphangiogenesis is involved in preeclampsia

INTRODUCTION

Pre-eclampsia (PE) is characterized by failed remodeling of maternal vessels perfusing the placenta. Blood vessels and lymphatic system are involved in vessel remodeling and flow homeostasis in the uterus during pregnancy. This study aims to investigate the involvement of angiogenesis and lymphangiogenesis in PE.

METHODS

Placental and decidual tissues were obtained from pregnancies with PE (n = 90), including PE cases with decidual vasculopathy (DV) (n = 52) and without DV (n = 38), and healthy pregnancies (control, n = 20). The clinical characteristics of these groups were analyzed. The expression levels of VEGF1, CD34, PROX-1, VEGFR3, and CD31 in the placenta and decidua were detected through immunohistochemistry, reverse-transcription polymerase chain reaction, and Western blot.

RESULTS

The lymphangiogenic markers PROX-1 and VEGFR3 were negatively expressed in the placenta but positively expressed in the decidua. The expression levels of the angiogenic markers VEGF1 and CD34 and the panendothelial marker CD31 were significantly lower in the placenta and decidua of the PE group than in those of the control group. The expression levels of VEGF1, CD34, and CD31 were significantly lower in the placenta and decidua with DV than in those without DV. Furthermore, the expression trends of PROX-1 and VEGFR3 was similar to those of VEGF1, CD34, and CD31 among the groups.

CONCLUSIONS

Lymphangiogenesis occurred in the decidua but not in the placenta. Impaired angiogenesis and lymphangiogenesis were associated with PE, particularly in the presence of DV.

The value of using schools as community assets for health

In planning, designing, procuring and ensuring delivery of improved services ('commissioning') for the school age population, the outcomes should be students who are healthy to learn and who learn to be healthy. Intuitively, linking education and health development together within the wider learning environment seems a good start to planning school health. However there has been a shortage of either theoretical models that can span different settings or experimental research that demonstrates improved community health. Is there evidence that the wider learning environment provided in a school is valuable in improving health? An initial scoping exercise identified domains of health where there was a promise of health gain. International literature on school health outcomes using the framework of Asset-Based Community Development (ABCD) has been reviewed. It was found that research on a variety of interventions was relevant to schools as an asset for public health. Effective areas for health gain were identified for local planning and evaluation using this community model. However, none of the studies reviewed was originally designed to test schools as assets and most of the research lacked methodological rigour, especially regarding children in low income countries. The ABCD model could help national governments develop resources for both education and health, but there is a global need to generate better quality evidence. Then people who commission for their local communities can make more effective use of these multifaceted assets to improve health and education outcomes for children.

The Best Laid Plans: Access to the Rajiv Aarogyasri community health insurance scheme of Andhra Pradesh

This paper is a qualitative assessment of a public health insurance scheme in the state of Andhra Pradesh, south India, called the Rajiv Aarogyasri Community Health Insurance Scheme (or Aarogyasri), using the case-study method. Focusing on inpatient hospital care and especially on surgical treatments leaves the scheme wanting in meeting the health care needs of and addressing the impoverishing health expenditure incurred by the poor, especially those living in rural areas. Though well-intentioned, people from vulnerable sections of society may find the scheme ultimately unhelpful for their needs. Through an in-depth qualitative approach, the paper highlights not just financial difficulties but also the non-financial barriers to accessing health care, despite the existence of a scheme such as Aarogyasri. Narrative evidence from poor households offers powerful insights into why even the most innovative state health insurance schemes may not achieve their goals and systemic corrections needed to address barriers to health care.