Progranulin AAV gene therapy for frontotemporal dementia: translational studies and phase 1/2 trial interim results

GRN mutations cause progranulin haploinsufficiency, which eventually leads to frontotemporal dementia (FTD-GRN). PR006 is an investigational gene therapy delivering the granulin gene (GRN) using an adeno-associated virus serotype 9 (AAV9) vector. In non-clinical studies, PR006 transduced neurons derived from induced pluripotent stem cells of patients with FTD-GRN, resulted in progranulin expression and improvement of lipofuscin, lysosomal and neuroinflammation pathologies in Grn-knockout mice, and was well tolerated except for minimal, asymptomatic dorsal root ganglionopathy in non-human primates. We initiated a first-in-human phase 1/2 open-label trial. Here we report results of a pre-specified interim analysis triggered with the last treated patient of the low-dose cohort (n = 6) reaching the 12-month follow-up timepoint. We also include preliminary data from the mid-dose cohort (n = 7). Primary endpoints were safety, immunogenicity and change in progranulin levels in cerebrospinal fluid (CSF) and blood. Secondary endpoints were Clinical Dementia Rating (CDR) plus National Alzheimer's Disease Coordinating Center (NACC) Frontotemporal Lobar Degeneration (FTLD) rating scale and levels of neurofilament light chain (NfL). One-time administration of PR006 into the cisterna magna was generally safe and well tolerated. All patients developed treatment-emergent anti-AAV9 antibodies in the CSF, but none developed anti-progranulin antibodies. CSF pleocytosis was the most common PR006-related adverse event. Twelve serious adverse events occurred, mostly unrelated to PR006. Deep vein thrombosis developed in three patients. There was one death (unrelated) occurring 18 months after treatment. CSF progranulin increased after PR006 treatment in all patients; blood progranulin increased in most patients but only transiently. NfL levels transiently increased after PR006 treatment, likely reflecting dorsal root ganglia toxicity. Progression rates, based on the CDR scale, were within the broad ranges reported for patients with FTD. These data provide preliminary insights into the safety and bioactivity of PR006. Longer follow-up and additional studies are needed to confirm the safety and potential efficacy of PR006. ClinicalTrials.gov identifier: NCT04408625 .

Transcriptional determinants of lipid mobilization in human adipocytes

Defects in adipocyte lipolysis drive multiple aspects of cardiometabolic disease, but the transcriptional framework controlling this process has not been established. To address this, we performed a targeted perturbation screen in primary human adipocytes. Our analyses identified 37 transcriptional regulators of lipid mobilization, which we classified as (i) transcription factors, (ii) histone chaperones, and (iii) mRNA processing proteins. On the basis of its strong relationship with multiple readouts of lipolysis in patient samples, we performed mechanistic studies on one hit, ZNF189, which encodes the zinc finger protein 189. Using mass spectrometry and chromatin profiling techniques, we show that ZNF189 interacts with the tripartite motif family member TRIM28 and represses the transcription of an adipocyte-specific isoform of phosphodiesterase 1B (PDE1B2). The regulation of lipid mobilization by ZNF189 requires PDE1B2, and the overexpression of PDE1B2 is sufficient to attenuate hormone-stimulated lipolysis. Thus, our work identifies the ZNF189-PDE1B2 axis as a determinant of human adipocyte lipolysis and highlights a link between chromatin architecture and lipid mobilization.

Bluetongue disease in sheep in New South Wales - April 2023

In 2016, bluetongue virus (BTV), serotype 16 (BTV-16), was detected in New South Wales (NSW) in sentinel cattle for the first time. Over the next 6 years, BTV-16 has been detected regularly and over an increasing area of the BTV zone in NSW. In April 2023, disease was reported in sheep on two farms on the Northern Tablelands of NSW. The consistent clinical signs included reduced exercise tolerance, facial swelling, serous nasal discharges with encrustation of the nasal plane, subcutaneous oedema of the neck and brisket and variable congestion of the coronary band. Affected sheep were mainly mature ewes and rams, with an estimated morbidity of 20% over a period of 6-8 weeks. Although there were several unexpected deaths, no veterinary examination was sought. Predominantly BTV-16 RNA was detected in sick sheep, with an incidence of infection of approximately 40% in a cross section of one flock. These events represent the first confirmation of disease due to bluetongue virus in NSW. As these cases occurred in a region with a high density of sheep, if there is ongoing transmission of BTV-16 during subsequent summers, further disease might be expected.

Lipids as Emerging Biomarkers in Neurodegenerative Diseases

Biomarkers are molecules that can be used to observe changes in an individual's biochemical or medical status and provide information to aid diagnosis or treatment decisions. Dysregulation in lipid metabolism in the brain is a major risk factor for many neurodegenerative disorders, including frontotemporal dementia, Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Thus, there is a growing interest in using lipids as biomarkers in neurodegenerative diseases, with the anionic phospholipid bis(monoacylglycerol)phosphate and (glyco-)sphingolipids being the most promising lipid classes thus far. In this review, we provide a general overview of lipid biology, provide examples of abnormal lysosomal lipid metabolism in neurodegenerative diseases, and discuss how these insights might offer novel and promising opportunities in biomarker development and therapeutic discovery. Finally, we discuss the challenges and opportunities of lipid biomarkers and biomarker panels in diagnosis, prognosis, and/or treatment response in the clinic.

Understanding medical civil-military relationships within the humanitarian-development-peace 'triple nexus': a typology to enable effective discourse

The interface between humanitarianism, development and peacebuilding is increasingly congested. Western foreign policies have shifted towards pro-active stabilisation agendae and so Civil-Military Relationships (CMRel) will inevitably be more frequent. Debate is hampered by lack of a common language or clear, mutually understood operational contexts to define such relationships. Often it may be easier to simply assume that military co-operation attempts are solely to 'win hearts and minds', rather than attempt to navigate the morass of different acronyms. In healthcare, such relationships are common and more complex - partly as health is seen as both an easy entry point for diplomacy and so is a priority for militaries, and because health is so critical to apolitical humanitarian responses. This paper identifies the characteristics of commonly described kinds of CMRel, and then derives a typology that describe them in functional groups as they apply to healthcare-related contexts (although it is likely to be far more widely applicable). Three broad classifications are described, and then mapped against 6 axes; the underlying military and civilian motivations, the level of the engagement (strategic to tactical), the relative stability of the geographical area, and finally the alignment between the civilian and military interests. A visual representation shows where different types may co-exist, and where they are likely to be more problematic. The model predicts two key areas where friction is likely; tactical interactions in highly unstable areas and in lower threat areas where independent military activity may undermine ongoing civilian programmes. The former is well described, supporting the typology. The latter is not and represents an ideal area for future study. In short, we describe an in-depth typology mapping the Civil-Military space in humanitarian and development contexts with a focus on healthcare, defining operational spaces and the identifying of areas of synergy and friction.

Deficiency of the frontotemporal dementia gene GRN results in gangliosidosis

Haploinsufficiency of GRN causes frontotemporal dementia (FTD). The GRN locus produces progranulin (PGRN), which is cleaved to lysosomal granulin polypeptides. The function of lysosomal granulins and why their absence causes neurodegeneration are unclear. Here we discover that PGRN-deficient human cells and murine brains, as well as human frontal lobes from GRN-mutation FTD patients have increased levels of gangliosides, glycosphingolipids that contain sialic acid. In these cells and tissues, levels of lysosomal enzymes that catabolize gangliosides were normal, but levels of bis(monoacylglycero)phosphates (BMP), lipids required for ganglioside catabolism, were reduced with PGRN deficiency. Our findings indicate that granulins are required to maintain BMP levels to support ganglioside catabolism, and that PGRN deficiency in lysosomes leads to gangliosidosis. Lysosomal ganglioside accumulation may contribute to neuroinflammation and neurodegeneration susceptibility observed in FTD due to PGRN deficiency and other neurodegenerative diseases.

The Lipid Droplet Knowledge Portal: A resource for systematic analyses of lipid droplet biology

Lipid droplets (LDs) are organelles of cellular lipid storage with fundamental roles in energy metabolism and cell membrane homeostasis. There has been an explosion of research into the biology of LDs, in part due to their relevance in diseases of lipid storage, such as atherosclerosis, obesity, type 2 diabetes, and hepatic steatosis. Consequently, there is an increasing need for a resource that combines datasets from systematic analyses of LD biology. Here, we integrate high-confidence, systematically generated human, mouse, and fly data from studies on LDs in the framework of an online platform named the "Lipid Droplet Knowledge Portal" (https://lipiddroplet.org/). This scalable and interactive portal includes comprehensive datasets, across a variety of cell types, for LD biology, including transcriptional profiles of induced lipid storage, organellar proteomics, genome-wide screen phenotypes, and ties to human genetics. This resource is a powerful platform that can be utilized to identify determinants of lipid storage.

FIT2 is an acyl-coenzyme A diphosphatase crucial for endoplasmic reticulum homeostasis

The endoplasmic reticulum is a cellular hub of lipid metabolism, coordinating lipid synthesis with continuous changes in metabolic flux. Maintaining ER lipid homeostasis despite these fluctuations is crucial to cell function and viability. Here, we identify a novel mechanism that is crucial for normal ER lipid metabolism and protects the ER from dysfunction. We identify the molecular function of the evolutionarily conserved ER protein FIT2 as a fatty acyl–coenzyme A (CoA) diphosphatase that hydrolyzes fatty acyl–CoA to yield acyl 4′-phosphopantetheine. This activity of FIT2, which is predicted to be active in the ER lumen, is required in yeast and mammalian cells for maintaining ER structure, protecting against ER stress, and enabling normal lipid storage in lipid droplets. Our findings thus solve the long-standing mystery of the molecular function of FIT2 and highlight the maintenance of optimal fatty acyl–CoA levels as key to ER homeostasis.

APOE4 disrupts intracellular lipid homeostasis in human iPSC-derived glia

The E4 allele of the apolipoprotein E gene (APOE) has been established as a genetic risk factor for many diseases including cardiovascular diseases and Alzheimer's disease (AD), yet its mechanism of action remains poorly understood. APOE is a lipid transport protein, and the dysregulation of lipids has recently emerged as a key feature of several neurodegenerative diseases including AD. However, it is unclear how APOE4 perturbs the intracellular lipid state. Here, we report that APOE4, but not APOE3, disrupted the cellular lipidomes of human induced pluripotent stem cell (iPSC)-derived astrocytes generated from fibroblasts of APOE4 or APOE3 carriers, and of yeast expressing human APOE isoforms. We combined lipidomics and unbiased genome-wide screens in yeast with functional and genetic characterization to demonstrate that human APOE4 induced altered lipid homeostasis. These changes resulted in increased unsaturation of fatty acids and accumulation of intracellular lipid droplets both in yeast and in APOE4-expressing human iPSC-derived astrocytes. We then identified genetic and chemical modulators of this lipid disruption. We showed that supplementation of the culture medium with choline (a soluble phospholipid precursor) restored the cellular lipidome to its basal state in APOE4-expressing human iPSC-derived astrocytes and in yeast expressing human APOE4 Our study illuminates key molecular disruptions in lipid metabolism that may contribute to the disease risk linked to the APOE4 genotype. Our study suggests that manipulating lipid metabolism could be a therapeutic approach to help alleviate the consequences of carrying the APOE4 allele.

Civilian perception of the role of the military in Nigeria's 2014 Ebola outbreak and health-related responses in the North East region

INTRODUCTION

Civilian-military relations play an important yet under-researched role in low-income and middle-income country epidemic response. One crucial component of civilian-military relations is defining the role of the military. This paper evaluates the role of Nigerian military during the 2014-2016 West African Ebola epidemic.

METHODS

Focus groups and key informant interviews were conducted throughout three states in North East region of Nigeria: Borno, Yobe and Adamawa. Participants were identified through mapping of stakeholder involvement in Nigerian epidemic response. English-translated transcripts of each key informant interview and focus group discussion were then coded and key themes were elucidated and analysed.

RESULTS

Major themes elucidated include developing inclusive coordination plans between civilian and military entities, facilitating human rights reporting mechanisms and distributing military resources more equitably across geographical catchment areas. The Nigerian Military served numerous functions: 37% (22/59) of respondents indicated 'security/peace' as the military's primary function, while 42% (25/59) cited health services. Variations across geographic settings were also noted: 35% (7/20) of participants in Borno stated the military primarily provided transportation, while 73% (11/15) in Adamawa and 29% (7/24) in Yobe listed health services.

CONCLUSIONS

Robust civilian-military relations require an appropriately defined role of the military and clear civilian-military communication. Important considerations to contextualise civilian-military relations include military cultural-linguistic understanding, human rights promotion, and community-based needs assessments; such foci can facilitate the military's understanding of community norms and civilian cooperation with military aims. In turn, more robust civilian-military relations can promote overall epidemic response and reduce the global burden of disease.

Cardiac Magnetic Resonance Stress Perfusion Imaging for Evaluation of Patients With Chest Pain

BACKGROUND

Stress cardiac magnetic resonance imaging (CMR) has demonstrated excellent diagnostic and prognostic value in single-center studies.

OBJECTIVES

This study sought to investigate the prognostic value of stress CMR and downstream costs from subsequent cardiac testing in a retrospective multicenter study in the United States.

METHODS

In this retrospective study, consecutive patients from 13 centers across 11 states who presented with a chest pain syndrome and were referred for stress CMR were followed for a target period of 4 years. The authors associated CMR findings with a primary outcome of cardiovascular death or nonfatal myocardial infarction using competing risk-adjusted regression models and downstream costs of ischemia testing using published Medicare national payment rates.

RESULTS

In this study, 2,349 patients (63 ± 11 years of age, 47% female) were followed for a median of 5.4 years. Patients with no ischemia or late gadolinium enhancement (LGE) by CMR, observed in 1,583 patients (67%), experienced low annualized rates of primary outcome (<1%) and coronary revascularization (1% to 3%), across all years of study follow-up. In contrast, patients with ischemia+/LGE+ experienced a >4-fold higher annual primary outcome rate and a >10-fold higher rate of coronary revascularization during the first year after CMR. Patients with ischemia and LGE both negative had low average annual cost spent on ischemia testing across all years of follow-up, and this pattern was similar across the 4 practice environments of the participating centers.

CONCLUSIONS

In a multicenter U.S. cohort with stable chest pain syndromes, stress CMR performed at experienced centers offers effective cardiac prognostication. Patients without CMR ischemia or LGE experienced a low incidence of cardiac events, little need for coronary revascularization, and low spending on subsequent ischemia testing. (Stress CMR Perfusion Imaging in the United States [SPINS]: A Society for Cardiovascular Resonance Registry Study; NCT03192891)

Hepatocyte Deletion of Triglyceride-Synthesis Enzyme Acyl CoA: Diacylglycerol Acyltransferase 2 Reduces Steatosis Without Increasing Inflammation or Fibrosis in Mice

Nonalcoholic fatty liver disease (NAFLD) is characterized by excess lipid accumulation in hepatocytes and represents a huge public health problem owing to its propensity to progress to nonalcoholic steatohepatitis, fibrosis, and liver failure. The lipids stored in hepatic steatosis (HS) are primarily triglycerides (TGs) synthesized by two acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. Either DGAT1 or DGAT2 catalyzes this reaction, and these enzymes have been suggested to differentially utilize exogenous or endogenously synthesized fatty acids, respectively. DGAT2 has been linked to storage of fatty acids from de novo lipogenesis, a process increased in NAFLD. However, whether DGAT2 is more responsible for lipid accumulation in NAFLD and progression to fibrosis is currently unknown. Also, it is unresolved whether DGAT2 can be safely inhibited as a therapy for NAFLD. Here, we induced NAFLD-like disease in mice by feeding a diet rich in fructose, saturated fat, and cholesterol and found that hepatocyte-specific Dgat2 deficiency reduced expression of de novo lipogenesis genes and lowered liver TGs by ~70%. Importantly, the reduction in steatosis was not accompanied by increased inflammation or fibrosis, and insulin and glucose metabolism were unchanged. Conclusion: This study suggests that hepatic DGAT2 deficiency successfully reduces diet-induced HS and supports development of DGAT2 inhibitors as a therapeutic strategy for treating NAFLD and preventing downstream consequences.

Probing the Global Cellular Responses to Lipotoxicity Caused by Saturated Fatty Acids

Excessive levels of saturated fatty acids are toxic to cells, although the basis for this lipotoxicity remains incompletely understood. Here, we analyzed the transcriptome, lipidome, and genetic interactions of human leukemia cells exposed to palmitate. Palmitate treatment increased saturated glycerolipids, accompanied by a transcriptional stress response, including upregulation of the endoplasmic reticulum (ER) stress response. A comprehensive genome-wide short hairpin RNA (shRNA) screen identified >350 genes modulating lipotoxicity. Among previously unknown genetic modifiers of lipotoxicity, depletion of RNF213, a putative ubiquitin ligase mutated in Moyamoya vascular disease, protected cells from lipotoxicity. On a broader level, integration of our comprehensive datasets revealed that changes in di-saturated glycerolipids, but not other lipid classes, are central to lipotoxicity in this model. Consistent with this, inhibition of ER-localized glycerol-3-phosphate acyltransferase activity protected from all aspects of lipotoxicity. Identification of genes modulating the response to saturated fatty acids may reveal novel therapeutic strategies for treating metabolic diseases linked to lipotoxicity.

Genome-wide CRISPR screens for Shiga toxins and ricin reveal Golgi proteins critical for glycosylation

Glycosylation is a fundamental modification of proteins and membrane lipids. Toxins that utilize glycans as their receptors have served as powerful tools to identify key players in glycosylation processes. Here, we carried out Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9-mediated genome-wide loss-of-function screens using two related bacterial toxins, Shiga-like toxins (Stxs) 1 and 2, which use a specific glycolipid, globotriaosylceramide (Gb3), as receptors, and the plant toxin ricin, which recognizes a broad range of glycans. The Stxs screens identified major glycosyltransferases (GTs) and transporters involved in Gb3 biosynthesis, while the ricin screen identified GTs and transporters involved in N-linked protein glycosylation and fucosylation. The screens also identified lysosomal-associated protein transmembrane 4 alpha (LAPTM4A), a poorly characterized four-pass membrane protein, as a factor specifically required for Stxs. Mass spectrometry analysis of glycolipids and their precursors demonstrates that LAPTM4A knockout (KO) cells lack Gb3 biosynthesis. This requirement of LAPTM4A for Gb3 synthesis is not shared by its homolog lysosomal-associated protein transmembrane 4 beta (LAPTM4B), and switching the domains between them determined that the second luminal domain of LAPTM4A is required, potentially acting as a specific "activator" for the GT that synthesizes Gb3. These screens also revealed two Golgi proteins, Transmembrane protein 165 (TMEM165) and Transmembrane 9 superfamily member 2 (TM9SF2), as shared factors required for both Stxs and ricin. TMEM165 KO and TM9SF2 KO cells both showed a reduction in not only Gb3 but also other glycosphingolipids, suggesting that they are required for maintaining proper levels of glycosylation in general in the Golgi. In addition, TM9SF2 KO cells also showed defective endosomal trafficking. These studies reveal key Golgi proteins critical for regulating glycosylation and glycolipid synthesis and provide novel therapeutic targets for blocking Stxs and ricin toxicity.

Endocannabinoids in Caenorhabditis elegans are essential for the mobilization of cholesterol from internal reserves

Proper cholesterol transport is crucial for the functionality of cells. In C. elegans, certain cholesterol derivatives called dafachronic acids (DAs) govern the entry into diapause. In their absence, worms form a developmentally arrested dauer larva. Thus, cholesterol transport to appropriate places for DA biosynthesis warrants the reproductive growth. Recently, we discovered a novel class of glycosphingolipids, PEGCs, required for cholesterol mobilization/transport from internal storage pools. Here, we identify other components involved in this process. We found that strains lacking polyunsaturated fatty acids (PUFAs) undergo increased dauer arrest when grown without cholesterol. This correlates with the depletion of the PUFA-derived endocannabinoids 2-arachidonoyl glycerol and anandamide. Feeding of these endocannabinoids inhibits dauer formation caused by PUFAs deficiency or impaired cholesterol trafficking (e.g. in Niemann-Pick C1 or DAF-7/TGF-β mutants). Moreover, in parallel to PEGCs, endocannabinoids abolish the arrest induced by cholesterol depletion. These findings reveal an unsuspected function of endocannabinoids in cholesterol trafficking regulation.

NAD+ Is a Food Component That Promotes Exit from Dauer Diapause in Caenorhabditis elegans

The free-living soil nematode Caenorhabditis elegans adapts its development to the availability of food. When food is scarce and population density is high, worms enter a developmentally arrested non-feeding diapause stage specialized for long-term survival called the dauer larva. When food becomes available, they exit from the dauer stage, resume growth and reproduction. It has been postulated that compound(s) present in food, referred to as the “food signal”, promote exit from the dauer stage. In this study, we have identified NAD⁺ as a component of bacterial extract that promotes dauer exit. NAD⁺, when dissolved in alkaline medium, causes opening of the mouth and ingestion of food. We also show that to initiate exit from the dauer stage in response to NAD⁺ worms require production of serotonin. Thus, C. elegans can use redox cofactors produced by dietary organisms to sense food.

Towards an alternative testing strategy for nanomaterials used in nanomedicine: lessons from NanoTEST

In spite of recent advances in describing the health outcomes of exposure to nanoparticles (NPs), it still remains unclear how exactly NPs interact with their cellular targets. Size, surface, mass, geometry, and composition may all play a beneficial role as well as causing toxicity. Concerns of scientists, politicians and the public about potential health hazards associated with NPs need to be answered. With the variety of exposure routes available, there is potential for NPs to reach every organ in the body but we know little about the impact this might have. The main objective of the FP7 NanoTEST project ( www.nanotest-fp7.eu ) was a better understanding of mechanisms of interactions of NPs employed in nanomedicine with cells, tissues and organs and to address critical issues relating to toxicity testing especially with respect to alternatives to tests on animals. Here we describe an approach towards alternative testing strategies for hazard and risk assessment of nanomaterials, highlighting the adaptation of standard methods demanded by the special physicochemical features of nanomaterials and bioavailability studies. The work has assessed a broad range of toxicity tests, cell models and NP types and concentrations taking into account the inherent impact of NP properties and the effects of changes in experimental conditions using well-characterized NPs. The results of the studies have been used to generate recommendations for a suitable and robust testing strategy which can be applied to new medical NPs as they are developed.

Tetrahydro-pyrimido-indoles as selective LIMK inhibitors: synthesis, selectivity profiling and structure–activity studies

Extensive structure–activity studies on three different modification sites resulted in a series of LIM kinase inhibitors, containing a novel tricyclic hinge-binding motif based on the pyrrolopyrimidine scaffold.

Hospital to home paediatric enteral nutrition--parents need support

This study assessed the provision of education and support to parents of children on home enteral nutrition (HEN), current dietetic support available and perceived challenges facing parents and carers. From the 39 responses (13%), 29 (83%, n = 35) parents suggested services for HEN need improvement. 29 (74%, n = 39) parents wanted more structured follow up and 22 (56%) would like one person to co-ordinate HEN, education and discharge. 7 parents (18%) reported a need for further education of health care professionals (HCP). Hospital dietitians were the most common HCPs reported to provide support to patients following discharge. Specialist paediatric HEN dietetic services working in a dedicated HEN team, who would provide accurate training and education and liaise with both parents and community care services post discharge should be in place. This would facilitate transfer to community care, reduce hospital re-admissions, outpatient department attendances and costs.

Products of the Parkinson's disease-related glyoxalase DJ-1, D-lactate and glycolate, support mitochondrial membrane potential and neuronal survival

Parkinson's disease is associated with mitochondrial decline in dopaminergic neurons of the substantia nigra. One of the genes linked with the onset of Parkinson's disease, DJ-1/PARK7, belongs to a novel glyoxalase family and influences mitochondrial activity. It has been assumed that glyoxalases fulfill this task by detoxifying aggressive aldehyde by-products of metabolism. Here we show that supplying either D-lactate or glycolate, products of DJ-1, rescues the requirement for the enzyme in maintenance of mitochondrial potential. We further show that glycolic acid and D-lactic acid can elevate lowered mitochondrial membrane potential caused by silencing PINK-1, another Parkinson's related gene, as well as by paraquat, an environmental toxin known to be linked with Parkinson's disease. We propose that DJ-1 and consequently its products are components of a novel pathway that stabilizes mitochondria during cellular stress. We go on to show that survival of cultured mesencephalic dopaminergic neurons, defective in Parkinson's disease, is enhanced by glycolate and D-lactate. Because glycolic and D-lactic acids occur naturally, they are therefore a potential therapeutic route for treatment or prevention of Parkinson's disease.

A wax ester promotes collective host finding in the nematode Pristionchus pacificus

Survival of nematode species depends on how successfully they disperse in the habitat and find a new host. As a new strategy for collective host finding in the nematode Pristionchus pacificus, dauer larvae synthesize an extremely long-chain polyunsaturated wax ester (nematoil) that covers the surface of the animal. The oily coat promotes congregation of up to one thousand individuals into stable 'dauer towers' that can reach a beetle host more easily.

Molecular strategies of the Caenorhabditis elegans dauer larva to survive extreme desiccation

Massive water loss is a serious challenge for terrestrial animals, which usually has fatal consequences. However, some organisms have developed means to survive this stress by entering an ametabolic state called anhydrobiosis. The molecular and cellular mechanisms underlying this phenomenon are poorly understood. We recently showed that Caenorhabditis elegans dauer larva, an arrested stage specialized for survival in adverse conditions, is resistant to severe desiccation. However, this requires a preconditioning step at a mild desiccative environment to prepare the organism for harsher desiccation conditions. A systems approach was used to identify factors that are activated during this preconditioning. Using microarray analysis, proteomics, and bioinformatics, genes, proteins, and biochemical pathways that are upregulated during this process were identified. These pathways were validated via reverse genetics by testing the desiccation tolerances of mutants. These data show that the desiccation response is activated by hygrosensation (sensing the desiccative environment) via head neurons. This leads to elimination of reactive oxygen species and xenobiotics, expression of heat shock and intrinsically disordered proteins, polyamine utilization, and induction of fatty acid desaturation pathway. Remarkably, this response is specific and involves a small number of functional pathways, which represent the generic toolkit for anhydrobiosis in plants and animals.

Stereoselective synthesis and hormonal activity of novel dafachronic acids and naturally occurring steroids isolated from corals

A stereoselective synthesis of (25S)-Δ(1)-, (25S)-Δ(1,4)-, (25S)-Δ(1,7)-, (25S)-Δ(8(14))-, (25S)-Δ(4,6,8(14))-dafachronic acid, methyl (25S)-Δ(1,4)-dafachronate and (25S)-5α-hydroxy-3,6-dioxocholest-7-en-26-oic acid is described. (25S)-Δ(1,4)-Dafachronic acid and its methyl ester are natural products isolated from corals and have been obtained by synthesis for the first time. (25S)-5α-Hydroxy-3,6-dioxocholest-7-en-26-oic acid represents a promising synthetic precursor for cytotoxic marine steroids.

Evolution of an endofungal lifestyle: Deductions from the Burkholderia rhizoxinica genome

BACKGROUND

Burkholderia rhizoxinica is an intracellular symbiont of the phytopathogenic zygomycete Rhizopus microsporus, the causative agent of rice seedling blight. The endosymbiont produces the antimitotic macrolide rhizoxin for its host. It is vertically transmitted within vegetative spores and is essential for spore formation of the fungus. To shed light on the evolution and genetic potential of this model organism, we analysed the whole genome of B. rhizoxinica HKI 0454 - a type strain of endofungal Burkholderia species.

RESULTS

The genome consists of a structurally conserved chromosome and two plasmids. Compared to free-living Burkholderia species, the genome is smaller in size and harbors less transcriptional regulator genes. Instead, we observed accumulation of transposons over the genome. Prediction of primary metabolic pathways and transporters suggests that endosymbionts consume host metabolites like citrate, but might deliver some amino acids and cofactors to the host. The rhizoxin biosynthesis gene cluster shows evolutionary traces of horizontal gene transfer. Furthermore, we analysed gene clusters coding for nonribosomal peptide synthetases (NRPS). Notably, B. rhizoxinica lacks common genes which are dedicated to quorum sensing systems, but is equipped with a large number of virulence-related factors and putative type III effectors.

CONCLUSIONS

B. rhizoxinica is the first endofungal bacterium, whose genome has been sequenced. Here, we present models of evolution, metabolism and tools for host-symbiont interaction of the endofungal bacterium deduced from whole genome analyses. Genome size and structure suggest that B. rhizoxinica is in an early phase of adaptation to the intracellular lifestyle (genome in transition). By analysis of tranporters and metabolic pathways we predict how metabolites might be exchanged between the symbiont and its host. Gene clusters for biosynthesis of secondary metabolites represent novel targets for genomic mining of cryptic natural products. In silico analyses of virulence-associated genes, secreted proteins and effectors might inspire future studies on molecular mechanisms underlying bacterial-fungal interaction.

Lung exposure to nanoparticles modulates an asthmatic response in a mouse model

The aim of this study was to investigate the modulation of an asthmatic response by titanium dioxide (TiO₂) or gold (Au) nanoparticles (NPs) in a murine model of diisocyanate-induced asthma. On days 1 and 8, BALB/c mice received 0.3% toluene diisocyanate (TDI) or the vehicle acetone-olive oil (AOO) on the dorsum of both ears (20 μL). On day 14, the mice were oropharyngeally dosed with 40 μL of a NP suspension (0.4 mg·mL⁻¹ (∼0.8 mg·kg⁻¹) TiO₂ or Au). 1 day later (day 15), the mice received an oropharyngeal challenge with 0.01% TDI (20 μL). On day 16, airway hyperreactivity (AHR), bronchoalveolar lavage (BAL) cell and cytokine analysis, lung histology, and total serum immunoglobulin E were assessed. NP exposure in sensitised mice led to a two- (TiO₂) or three-fold (Au) increase in AHR, and a three- (TiO₂) or five-fold (Au) increase in BAL total cell counts, mainly comprising neutrophils and macrophages. The NPs taken up by BAL macrophages were identified by energy dispersive X-ray spectroscopy. Histological analysis revealed increased oedema, epithelial damage and inflammation. In conclusion, these results show that a low, intrapulmonary doses of TiO₂ or Au NPs can aggravate pulmonary inflammation and AHR in a mouse model of diisocyanate-induced asthma.

Human airway epithelial cells in culture for studying the molecular mechanisms of the inflammatory response triggered by diesel exhaust particles

Epidemiological studies have shown that particulate air pollution is linked to the increase of morbidity and mortality due to respiratory diseases. Diesel exhaust particles (DEPs), which are the most important part of PM2.5 in Western European and Japanese urban areas, have been suspected. The mechanisms of proinflammatory response induced by DEPS were elucidated using a human epithelial cell line (16-HBE). It has been shown that DEPs can be phagocytosed by HBE cells, inducing the release of cytokines. MAP kinase pathways (i.e., ERK1/2 and P38) were triggered as well as the activation of the nuclear factor NF-kappaB. Reactive oxygen species (ROS) were strongly incriminated in this response because DEPs induce the increase of intracellular hydroperoxides and antioxidants inhibit the release of DEP-induced cytokines, the activation of MAP kinases and NF-kappaB. Organic compounds adsorbed on DEPs seemed to be involved in the response and the production of ROS. Moreover, we have demonstrated that DEPs can activate CYP1A1 in HBE cells. These experimental results give biological plausibility to the epidemiological findings.

Organic compounds from diesel exhaust particles elicit a proinflammatory response in human airway epithelial cells and induce cytochrome p450 1A1 expression

Diesel exhaust particles (DEP) are known to enhance inflammatory responses in human volunteers. In cultured human bronchial epithelial (16HBE) cells, they induce the release of proinflammatory cytokines after triggering transduction pathways, including nuclear factor (NF)-kappaB activation and mitogen-activated protein kinase (MAPK) phosphorylation. This study compares the effects of native DEP (nDEP), organic extracts of DEP (OE-DEP), and carbonaceous particles, represented by stripped DEP (sDEP) and carbon black particles (CB), in order to clarify their respective roles. OE-DEP and nDEP induce granulocyte macrophage colony-stimulating factor (GM-CSF) release, NF-kappaB activation, and MAPK phosphorylation. The carbonaceous core generally induces less intense effects. Reactive oxygen species are produced in 16HBE cells and are involved in GM-CSF release and in the stimulation of NF-kappaB DNA binding by nDEP and OE-DEP. We demonstrate, for the first time, in airway epithelial cells in vitro that nDEP induce the expression of the CYP1A1, a cytochrome P450 specifically involved in polycyclic aromatic hydrocarbons metabolism, thereby demonstrating the critical role of organic compounds in the DEP-induced proinflammatory response. Understanding the respective contributions of DEP components in these effects is important for vehicle manufacturers in order to improve their exhaust gas post-treatment technologies. In conclusion, the DEP-induced inflammatory response in airway epithelial cells mainly involves organic compounds such as PAH, which induce CYP1A1 gene expression.

Similar cellular effects induced by diesel exhaust particles from a representative diesel vehicle recovered from filters and Standard Reference Material 1650

Standard reference diesel exhaust particles (DEP) SRM 1650 are often used to evaluate the toxicity of DEP. However, these particles did not necessarily reflect the effects of DEP representative of present diesel automobiles. This study was designed to compare the effects of SRM 1650 to DEP from representative cars (RC-DEP) on airway epithelial cells. Therefore we established a method to recover RC-DEP impacted on filters after emission from diesel automobiles on test beds. Electron microscopy and flow cytometry showed that these two types of particles were phagocytosed to the same extent by epithelial cells. This phagocytosis is not dependent on the adsorbed organic compounds in contrast to the cytotoxic effect evaluated by measurements of LDH release. This is emphasized by the fact that RC-DEP equipped with an oxidation catalyst are less cytotoxic than particles from a non-equipped vehicle or SRM 1650. This type of catalyst also reduces significantly the release of GM-CSF by bronchial epithelial cells. We have shown in the present paper that SRM 1650 may be used as a surrogate of DEP. However, exhaust gas post-treatment devices of current diesel automobiles reduce the cytotoxicity as well as the inflammatory response of these particles.

Airborne particles evoke an inflammatory response in human airway epithelium. Activation of transcription factors

PM10, the commonly used indicator of respirable environmental suspended particulate matter with a mean aerodynamic diameter of less than 10 microm, is composed of organic or elemental carbon aggregates containing various metals, acid salts, organic pollutants (polyaromatic hydrocarbons, quinones, nitroaromatic hydrocarbons, etc.), and biological contaminants. In urban and industrial areas, fossil fuel combustion products (e.g., diesel exhaust particles and residual oil fly ash) are the main contributors to PM10. Epidemiological data show that air pollution particulates cause adverse pulmonary health effects, especially in individuals with preexisting lung diseases. A critical cell type that encounters particles after inhalation and that is affected in a number of respiratory diseases is the epithelial cell of the airway and alveoli. In vitro studies have shown that PM10 is responsible for the production and the release of inflammatory cytokines by the respiratory tract epithelium as well as for the activation of the transcription factor NFkappaB. As many of the adsorbed materials on the particle surface are direct oxidants (metals, quinones) and indirectly produce reactive oxygen species, it is hypothesized that oxidative stress may be a component of the mechanisms by which particles activate cytokine production and NFkappaB in epithelial cells.

Mechanisms of GM-CSF increase by diesel exhaust particles in human airway epithelial cells

We have previously shown that exposure to diesel exhaust particles (DEPs) stimulates human airway epithelial cells to secrete the inflammatory cytokines interleukin-8, interleukin-1beta, and granulocyte-macrophage colony-stimulating factor (GM-CSF) involved in allergic diseases. In the present paper, we studied the mechanisms underlying the increase in GM-CSF release elicited by DEPs using the human bronchial epithelial cell line 16HBE14o-. RT-PCR analysis has shown an increase in GM-CSF mRNA levels after DEP treatments. Comparison of the effects of DEPs, extracted DEPs, or extracts of DEPs has shown that the increase in GM-CSF release is mainly due to the adsorbed organic compounds and not to the metals present on the DEP surface because the metal chelator desferrioxamine had no inhibitory effect. Furthermore, radical scavengers inhibited the DEP-induced GM-CSF release, showing involvement of reactive oxygen species in this response. Moreover genistein, a tyrosine kinase inhibitor, abrogated the effects of DEPs on GM-CSF release, whereas protein kinase (PK) C, PKA, cyclooxygenase, or lipoxygenase inhibitors had no effect. PD-98059, an inhibitor of mitogen-activated protein kinase, diminished the effects of DEPs, whereas SB-203580, an inhibitor of p38 mitogen-activated protein kinase, had a lower effect, and DEPs did actually increase the active, phosphorylated form of the extracellular signal-regulated kinase as shown by Western blotting. In addition, cytochalasin D, which inhibits the phagocytosis of DEPs, reduced the increase in GM-CSF release after DEP treatment. Together, these data suggest that the increase in GM-CSF release is mainly due to the adsorbed organic compounds and that the effect of native DEPs requires endocytosis of the particles. Reactive oxygen species and tyrosine kinase(s) may be involved in the DEP-triggered signaling of the GM-CSF response.

Diesel exhaust particles are taken up by human airway epithelial cells in vitro and alter cytokine production

The involvement of diesel exhaust particles (DEPs) in respiratory diseases was evaluated by studying their effects on two in vitro models of human airway epithelial cells. The cytotoxicity of DEPs, their phagocytosis, and the resulting immune response were investigated in a human bronchial epithelial cell line (16HBE14o-) as well as in human nasal epithelial cells in primary culture. DEP exposure induced a time- and dose-dependent membrane damage. Transmission electron microscopy showed that DEPs underwent endocytosis by epithelial cells and translocated through the epithelial cell sheet. Flow cytometric measurements allowed establishment of the time and dose dependency of this phagocytosis and its nonspecificity with different particles (DEPs, carbon black, and latex particles). DEPs also induced a time-dependent increase in interleukin-8, granulocyte-macrophage colony-stimulating factor, and interleukin-1beta release. This inflammatory response occurred later than phagocytosis, and its extent seems to depend on the content of adsorbed organic compounds because carbon black had no effect on cytokine release. Furthermore, exhaust gas posttreatments, which diminished the adsorbed organic compounds, reduced the DEP-induced increase in granulocyte-macrophage colony-stimulating factor release. These results suggest that DEPs could 1) be phagocytosed by airway epithelial cells and 2) induce a specific inflammatory response.

The role of arbitrarily primed PCR in identifying the source of an outbreak of Legionnaires' disease

An outbreak of community-acquired Legionnaires' disease (LD) occurred in Providence, R.I., in fall 1993. To find the outbreak source, exposures of 17 case patients were compared to those of 33 matched controls. Case patients were more likely than controls to have visited a section of downtown (area A) during the 2 weeks before illness (11 [65%] versus 9 [27%]; matched odds ratio, 6.5; P = 0.01). Water samples were cultured from 27 aerosol-producing devices within area A. Legionella pneumophila serogroup 1 isolates underwent monoclonal antibody (MAb) subtyping and arbitrarily primed PCR (AP-PCR). All four L. pneumophila serogroup 1 isolates available from case patients who visited area A had identical MAb and AP-PCR patterns. Among 14 environmental isolates, 5 had MAb patterns that matched the case patient isolates, but only 1 had a matching AP-PCR pattern. This investigation implicates a cooling tower in area A as the outbreak source and illustrates the usefulness of AP-PCR for identifying sources of LD outbreaks.

"Gallstone hip" and other sequelae of retained gallstones

The fate of gallstones spilled during laparoscopic cholecystostomy has been thought to be relatively benign. Recent experience and a review of the recent literature shows that this is not always the case. We report three cases of complications of retained stones and analyse the literature with regard to types of complications, time to presentation, and recommendations for managing spilled gallstones. Retained gallstones have been shown to cause adhesions in the rat and inflammatory reactions in dogs with no evidence of absorption. The average time to presentation of complications arising from retained gallstones is 27.3 weeks. Complications include: Intraabdominal abscess formation with or without abdominal wall sinus tract formation, persisting abdominal wall sinus tracts from port site abscess, subhepatic inflammatory masses, cholelithoptysis, microabscesses and granuloma formation, liver abscess and "dumbell" shaped abscess with one side of the "dumbell" forming a subcutaneous abscess. We recommend the judicious use of retrieval devices during the extraction phase of the laparoscopic cholecystectomy, diligent removal of any spilled stones and awareness of delayed postoperative pain and tenderness as a harbinger of symptomatic retained gallstones. Documentation of intraoperative gallstone spillage, volume, type of gallstones, and effort to retrieve is recommended.

TGF beta 1 promotes actin cytoskeleton reorganization and migratory phenotype in epithelial tracheal cells in primary culture

In the present study we have investigated the effects of transforming growth factor beta (TGF beta 1) on rabbit tracheal epithelial cells in primary culture, with respect to cell proliferation and differentiation. Epithelial tracheal cells derived from an explant plated on an extracellular matrix, formed an outgrowth resulting from cell division and cell migration. TGF beta 1 treatment produced a negative effect on cell proliferation, but in contrast, promoted a marked enhancement of cell migration and increase in outgrowth surface. TGF beta 1 induced marked cell shape changes, including cell spreading and lack of stratification, associated with reduced cell-cell contacts and increased cell-substratum anchorage, as seen by electron microscopic observations. Immunocytological studies demonstrated major TGF beta 1-induced actin cytoskeleton reorganization, corresponding to the development of a basal stress fiber network and decrease of the annular cell border, without affecting the tight junctions. The migratory phenotype was approached by microcinematography which clearly showed that TGF beta 1 triggered a stimulatory effect on migration of epithelial cells, determined using an image analyzing system. Present findings suggest a beneficial role for TGF beta 1 during wound healing in providing the acquisition of a migratory phenotype, with a higher capacity to migrate either on collagen or on different extracellular matrix components including laminin and fibronectin. Conversely, present data are not consistent with a squamous response to TGF beta 1, since metaplastic differentiation did not occur, as characterized by cytokeratin expression and cross-linked envelopes formation.

A transformational model for the practice of professional nursing. Part 2, Implementation of the model

Our healthcare system is undergoing major transformation. Most nurse executives are convinced that change is necessary and inevitable, but they are less certain how to position their departments for future success. The Transformational Model for the Practice of Professional Nursing was developed as a "road map" for that purpose. Part 1 (JONA, April 1994) discussed the professional practice paradigm shifts that are needed for future success. The model components were presented and applications identified. Part 2 discusses the implementation of this model in a practice setting.

A transformational model for the practice of professional nursing. Part 1, The model

Our healthcare system is undergoing major transformation. Most nurse executives know that change is necessary and inevitable, but are less certain how to position their departments for these changes. The Transformational Model for the Practice of Professional Nursing was developed as a "road map" for that purpose. Part 1 of the model discusses the paradigm shifts that need to occur in professional practice for future success. The various components of the model are presented, and applications are identified. Part 2 will appear in the May 1994 issue of JONA, and will discuss the implementation of this model into a practice setting.

Senile dementia of the Alzheimer type. Subject attrition and testability in research

There are inherent methodologic problems in investigating senile dementia of the Alzheimer type (SDAT) but this study indicated that, with regard to behavioral test measurement, some of the obvious problems are partially mitigated. First, these data showed that the progressive decline seen in longitudinal SDAT studies is of the same type and magnitude seen in cross-sectional comparisons. Thus, comparing SDAT groups differing in severity provides for the same observations as following up subjects with mild SDAT over time. This study also demonstrates that with certain kinds of tests, selective subject attrition may not be any greater in longitudinal investigations than found in normal aging research. Subjects who dropped out of the longitudinal study were not that different from those who remained in, at least in terms of initial test performance on challenging tests. In this study less than 5% of the subjects with SDAT originally classified as being in the mild stage of the disease remained in this stage after 6 3/4 years of investigation. This inexorable downward path of the subject with SDAT is what appears paramount. Given the similarity of staging in longitudinal and cross-sectional studies, prior test performance levels in the latter studies can be ascertained even if with less accuracy than in longitudinal studies.