Dual action of ATP hydrolysis couples lid closure to substrate release into the group II chaperonin chamber.

Group II chaperonins are ATP-dependent ring-shaped complexes that bind nonnative polypeptides and facilitate protein folding in archaea and eukaryotes. A built-in lid encapsulates substrate proteins within the central chaperonin chamber. Here, we describe the fate of the substrate during the nucleotide cycle of group II chaperonins. The chaperonin substrate-binding sites are exposed, and the lid is open in both the ATP-free and ATP-bound prehydrolysis states. ATP hydrolysis has a dual function in the folding cycle, triggering both lid closure and substrate release into the central chamber. Notably, substrate release can occur in the absence of a lid, and lid closure can occur without substrate release. However, productive folding requires both events, so that the polypeptide is released into the confined space of the closed chamber where it folds. Our results show that ATP hydrolysis coordinates the structural and functional determinants that trigger productive folding.

A bacterial binary toxin system that kills both insects and aquatic crustaceans: Photorhabdus insect-related toxins A and B.

Photorhabdus insect-related toxins A and B (PirA and PirB) were first recognized as insecticidal toxins from Photorhabdus luminescens. However, subsequent studies showed that their homologs from Vibrio parahaemolyticus also play critical roles in the pathogenesis of acute hepatopancreatic necrosis disease (AHPND) in shrimps. Based on the structural features of the PirA/PirB toxins, it was suggested that they might function in the same way as a Bacillus thuringiensis Cry pore-forming toxin. However, unlike Cry toxins, studies on the PirA/PirB toxins are still scarce, and their cytotoxic mechanism remains to be clarified. In this review, based on our studies of V. parahaemolyticus PirAvp/PirBvp, we summarize the current understanding of the gene locations, expression control, activation, and cytotoxic mechanism of this type of toxin. Given the important role these toxins play in aquatic disease and their potential use in pest control applications, we also suggest further topics for research. We hope the information presented here will be helpful for future PirA/PirB studies.

Synergistic Polymer Blending Informs Efficient Terpolymer Design and Machine Learning Discerns Performance Trends for pDNA Delivery.

Cationic polymers offer an alternative to viral vectors in nucleic acid delivery. However, the development of polymer vehicles capable of high transfection efficiency and minimal toxicity has remained elusive, and continued exploration of the vast design space is required. Traditional single polymer syntheses with large monomer bases are very time-intensive, limiting the speed at which new formulations are identified. In this work, we present an experimental method for the quick probing of the design space, utilizing a combinatorial set of 90 polymer blends, derived from 6 statistical copolymers, to deliver pDNA. This workflow facilitated rapid screening of polyplex compositions, successfully tailoring polyplex hydrophobicity, particle size, and payload binding affinity. This workflow identified blended polyplexes with high levels of transfection efficiency and cell viability relative to single copolymer controls and commercial JetPEI, indicating synergistic benefits from copolymer blending. Polyplex composition was coupled with biological outputs to guide the synthesis of single terpolymer vehicles, with high-performing polymers P10 and M20, providing superior transfection of HEK293T cells in serum-free and serum-containing media, respectively. Machine learning coupled with SHapley Additive exPlanations (SHAP) was used to identify polymer/polyplex attributes that most impact transfection efficiency, viability, and overall effective efficiency. Subsequent transfections on ARPE-19 and HDFn cells found that P10 and M20 were surpassed in performance by M10, contrasting with results in HEK293T cells. This cell type dependency reinforced the need to evaluate transfection conditions with multiple cell models to potentially identify moieties more beneficial to delivery in certain tissues. Overall, the workflow employed can be used to expedite the exploration of the polymer design space, bypassing extensive synthesis, and to develop improved polymer delivery vehicles more readily for nucleic acid therapies.

Developing an agenda for the decolonization of global health.

Colonialism, which involves the systemic domination of lands, markets, peoples, assets, cultures or political institutions to exploit, misappropriate and extract wealth and resources, affects health in many ways. In recent years, interest has grown in the decolonization of global health with a focus on correcting power imbalances between high-income and low-income countries and on challenging ideas and values of some wealthy countries that shape the practice of global health. We argue that decolonization of global health must also address the relationship between global health actors and contemporary forms of colonialism, in particular the current forms of corporate and financialized colonialism that operate through globalized systems of wealth extraction and profiteering. We present a three-part agenda for action that can be taken to decolonize global health. The first part relates to the power asymmetries that exist between global health actors from high-income and historically privileged countries and their counterparts in low-income and marginalized settings. The second part concerns the colonization of the structures and systems of global health governance itself. The third part addresses how colonialism occurs through the global health system. Addressing all forms of colonialism calls for a political and economic anticolonialism as well as social decolonization aimed at ensuring greater national, racial, cultural and knowledge diversity within the structures of global health.

Le colonialisme, qui implique la domination systémique de terres, de marchés, de peuples, de ressources, de cultures ou d'institutions politiques dans le but d'exploiter, de détourner et d'extraire des richesses et des ressources, affecte la santé de nombreuses manières. Ces dernières années, la décolonisation de la santé mondiale a suscité un intérêt croissant, l'accent étant mis sur la correction des déséquilibres de pouvoir entre les pays à revenu élevé et les pays à faible revenu, ainsi que sur la remise en question des idées et des valeurs de certains pays riches qui façonnent la pratique de la santé mondiale. Nous soutenons que la décolonisation de la santé mondiale doit également aborder la relation entre les acteurs de la santé mondiale et les formes contemporaines de colonialisme, en particulier les formes actuelles de colonialisme d'entreprise et de colonialisme financiarisé qui opèrent par des systèmes mondialisés d'extraction de richesses et de profits. Nous présentons un programme d'action en trois parties destiné à décoloniser la santé mondiale. La première partie porte sur les asymétries de pouvoir existant entre les acteurs de la santé mondiale des pays à hauts revenus et historiquement privilégiés et leurs homologues des pays à faibles revenus et marginalisés. La deuxième partie concerne la colonisation des structures et des systèmes de la gouvernance mondiale de la santé elle-même. La troisième partie traite de la manière dont le colonialisme se manifeste à travers le système de santé mondial. La lutte contre toutes les formes de colonialisme nécessite un anticolonialisme politique et économique ainsi qu'une décolonisation sociale visant à garantir une plus grande diversité nationale, raciale, culturelle et des connaissances au sein des structures de la santé mondiale.

El colonialismo, que implica la dominación sistémica de tierras, mercados, pueblos, bienes, culturas o instituciones políticas para explotar, apropiarse indebidamente y extraer riqueza y recursos, afecta a la salud de muchas maneras. En los últimos años ha crecido el interés por descolonizar la salud mundial, en particular para corregir los desequilibrios de poder entre los países de ingresos altos y los de ingresos bajos, y para cuestionar las ideas y los valores de algunos países ricos que influyen en la práctica de la salud mundial. Sostenemos que la descolonización de la salud mundial también debe abordar la relación entre los actores de la salud mundial y las formas contemporáneas de colonialismo, en especial las formas actuales de colonialismo corporativo y financiarizado que operan a través de sistemas globalizados de extracción de riqueza y especulación. Presentamos un programa de acción dividido en tres partes para descolonizar la salud mundial. La primera parte se refiere a las asimetrías de poder que existen entre los actores de la salud mundial procedentes de países de ingresos altos e históricamente privilegiados y sus homólogos de entornos de ingresos bajos y marginados. La segunda parte se refiere a la colonización de las estructuras y sistemas de la propia gobernanza de la salud mundial. La tercera parte aborda cómo se produce el colonialismo a través del sistema sanitario mundial. Abordar todas las formas de colonialismo exige un anticolonialismo político y económico, así como una descolonización social destinada a garantizar una mayor diversidad nacional, racial, cultural y de conocimientos dentro de las estructuras de la salud mundial.

Shrimp SIRT4 promotes white spot syndrome virus replication.

In WSSV pathogenesis, the molecular mechanisms and the key host factors that regulate the viral replication and morphogenesis remain unclear. However, like most viruses, WSSV is known to induce metabolic reprogramming in several metabolic pathways including the host glutamine metabolism, and several recent reports have suggested that the sirtuins SIRT3, SIRT4, and SIRT5, which belong to a family of NAD+-dependent deacetylases, play an important role in this regulation. Here we focus on characterizing LvSIRT4 from Litopenaeus vannamei and investigate its role in regulating glutamine dehydrogenase (GDH), an important enzyme that promotes glutaminolysis and viral replication. We found that LvSIRT4 silencing led to significant decreases in both WSSV gene expression and the number of viral genome copies. Conversely, overexpression of LvSIRT4 led to significant increases in the expression of WSSV genes and the WSSV genome copy number. Immunostaining in Sf9 insect cells confirmed the presence of LvSIRT4 in the mitochondria and the co-localization of LvSIRT4 and LvGDH in the same cellular locations. In vivo gene silencing of LvSIRT4 significantly reduced the gene expression of LvGDH whereas LvSIRT4 overexpression had no effect. However, neither silencing nor overexpression had any effect on the protein expression levels of LvGDH. Lastly, although GDH activity in uninfected shrimp was unchanged, the GDH enzyme activity in WSSV-infected shrimp was significantly increased after both LvSIRT4 silencing and overexpression. This suggests that although there may be no direct regulation, LvSIRT4 might still be able to indirectly regulate LvGDH via the mediation of one or more WSSV proteins that have yet to be identified.

"Current", "heated rods", and "hot vapour": why patients refuse radiotherapy as a treatment modality for cancer in northern Sri Lanka.

PURPOSE: Significant proportions of patients either refuse or discontinue radiotherapy, even in the curative setting, leading to poor clinical outcomes. This study explores patient perceptions that underlie decisions to refuse/discontinue radiotherapy at a cancer care facility in northern Sri Lanka. METHODS: An exploratory descriptive qualitative study was carried out among 14 purposively selected patients with cancer who refused/discontinued radiotherapy. In-depth semi-structured interviews were transcribed in Tamil, translated into English, coded, and thematically analyzed. RESULTS: All participants referred to radiotherapy as "current" with several understanding the procedure to involve electricity, heat, or hot vapour. Many pointed to gaps in information provided by healthcare providers, who were perceived to focus on side effects without explaining the procedure. In the absence of these crucial details, patients relied on family members and acquaintances for information, often based on second or third-hand accounts of experiences with radiotherapy. Many felt pressured by family to refuse radiation, feared radiation, or felt ashamed to ask questions, while for others COVID-19 was an impediment. All but three participants regretted their decision, claiming they would recommend radiation to patients with cancer, especially when it is offered with curative intent. CONCLUSION: Patients with cancer who refused/discontinued radiation therapy have significant information needs. While human resource deficits need to be addressed in low-resource settings like northern Sri Lanka, providing better supportive cancer care could improve clinical outcomes and save healthcare resources that would otherwise be wasted on patient preparation for radiotherapy.

Cytotoxicity of Vibrio parahaemolyticus AHPND toxin on shrimp hemocytes, a newly identified target tissue, involves binding of toxin to aminopeptidase N1 receptor.

Acute hepatopancreatic necrosis disease (AHPND) caused by PirABVP-producing strain of Vibrio parahaemolyticus, VPAHPND, has seriously impacted the shrimp production. Although the VPAHPND toxin is known as the VPAHPND virulence factor, a receptor that mediates its action has not been identified. An in-house transcriptome of Litopenaeus vannamei hemocytes allows us to identify two proteins from the aminopeptidase N family, LvAPN1 and LvAPN2, the proteins of which in insect are known to be receptors for Cry toxin. The membrane-bound APN, LvAPN1, was characterized to determine if it was a VPAHPND toxin receptor. The increased expression of LvAPN1 was found in hemocytes, stomach, and hepatopancreas after the shrimp were challenged with either VPAHPND or the partially purified VPAHPND toxin. LvAPN1 knockdown reduced the mortality, histopathological signs of AHPND in the hepatopancreas, and the number of virulent VPAHPND bacteria in the stomach after VPAHPND toxin challenge. In addition, LvAPN1 silencing prevented the toxin from causing severe damage to the hemocytes and sustained both the total hemocyte count (THC) and the percentage of living hemocytes. We found that the rLvAPN1 directly bound to both rPirAVP and rPirBVP toxins, supporting the notion that silencing of LvAPN1 prevented the VPAHPND toxin from passing through the cell membrane of hemocytes. We concluded that the LvAPN1 was involved in AHPND pathogenesis and acted as a VPAHPND toxin receptor mediating the toxin penetration into hemocytes. Besides, this was the first report on the toxic effect of VPAHPND toxin on hemocytes other than the known target tissues, hepatopancreas and stomach.

Resilience and probiotic interventions to prevent and recover from shrimp gut dysbiosis.

To counter the recurrent outbreaks of bacterial (acute hepatopancreatic necrosis disease; AHPND) and viral (white spot disease; WSD) shrimp diseases, which still remain a threat to the global industry, shrimp gut microbiota research has been gaining more attention in recent years, and the use of probiotics in aquaculture has had promising results in improving shrimp gut health and immunity. In this review based on our studies on AHPND and WSD, we summarize our current understanding of the shrimp gastrointestinal tract and the role of the microbiota in disease, as well as effects of probiotics. We focus particularly on the concept of microbiota resilience, and consider strategies that can be used to restore shrimp gut health by probiotic intervention at a crucial time during gut microbiota dysbiosis. Based on the available scientific evidence, we argue that the use of probiotics potentially has an important role in controlling disease in shrimp aquaculture.

Polymeric Delivery of Therapeutic Nucleic Acids.

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Systematic review of global hepatitis E outbreaks to inform response and coordination initiatives.

INTRODUCTION: Hepatitis E virus (HEV) is the most common cause of acute hepatitis. While symptoms are generally mild and resolve within weeks, some populations (e.g., pregnant women, immunocompromised adults) are at high-risk of severe HEV-related morbidity and mortality. There has not been a recent comprehensive review of contemporary HEV outbreaks, which limits the validity of current disease burden estimates. Therefore, we aimed to characterize global HEV outbreaks and describe data gaps to inform HEV outbreak prevention and response initiatives. METHODS: We performed a systematic review of peer-reviewed (PubMed, Embase) and gray literature (ProMED) to identify reports of outbreaks published between 2011 and 2022. We included (1) reports with ≥ 5 cases of HEV, and/or (2) reports with 1.5 times the baseline incidence of HEV in a specific population, and (3) all reports with suspected (e.g., clinical case definition) or confirmed (e.g., ELISA or PCR test) cases if they met criterium 1 and/or 2. We describe key outbreak epidemiological, prevention and response characteristics and major data gaps. RESULTS: We identified 907 records from PubMed, 468 from Embase, and 247 from ProMED. We screened 1,362 potentially relevant records after deduplication. Seventy-one reports were synthesized, representing 44 HEV outbreaks in 19 countries. The populations at risk, case fatalities, and outbreak durations were not reported in 66% of outbreak reports. No reports described using HEV vaccines. Reported intervention efforts included improving sanitation and hygiene, contact tracing/case surveillance, chlorinating boreholes, and advising residents to boil water. Commonly missing data elements included specific case definitions used, testing strategy and methods, seroprevalence, impacts of interventions, and outbreak response costs. Approximately 20% of HEV outbreaks we found were not published in the peer-reviewed literature. CONCLUSION: HEV represents a significant public health problem. Unfortunately, extensive data shortages and a lack of standardized reporting make it difficult to estimate the HEV disease burden accurately and to implement effective prevention and response activities. Our study has identified major gaps to guide future studies and outbreak reporting systems. Our results support the development of standardized reporting procedures/platforms for HEV outbreaks to ensure accurate and timely data distribution, including active and passive coordinated surveillance systems, particularly among high-risk populations.

Multiple Nucleocapsid Structural Forms of Shrimp White Spot Syndrome Virus Suggests a Novel Viral Morphogenetic Pathway.

White spot syndrome virus (WSSV) is a very large dsDNA virus. The accepted shape of the WSSV virion has been as ellipsoidal, with a tail-like extension. However, due to the scarcity of reliable references, the pathogenesis and morphogenesis of WSSV are not well understood. Here, we used transmission electron microscopy (TEM) and cryogenic electron microscopy (Cryo-EM) to address some knowledge gaps. We concluded that mature WSSV virions with a stout oval-like shape do not have tail-like extensions. Furthermore, there were two distinct ends in WSSV nucleocapsids: a portal cap and a closed base. A C14 symmetric structure of the WSSV nucleocapsid was also proposed, according to our Cryo-EM map. Immunoelectron microscopy (IEM) revealed that VP664 proteins, the main components of the 14 assembly units, form a ring-like architecture. Moreover, WSSV nucleocapsids were also observed to undergo unique helical dissociation. Based on these new results, we propose a novel morphogenetic pathway of WSSV.

Litopenaeus vannamei peritrophin interacts with WSSV and AHPND-causing V. parahaemolyticus to regulate disease pathogenesis.

Peritrophins are peritrophic membrane (PM) proteins that can interact with chitin fibers via chitin-binding domains. Peritrophins have essential roles in providing porosity and strength to the PM that lines the shrimp midgut. Acute hepatopancreatic necrosis disease (AHPND), caused by strains of V. parahaemolyticus, is known to initially colonize the shrimp stomach and simultaneously disrupt its structural barriers (e.g., cuticle or epithelial tissues) to reach the hepatopancreas. Although stomach and hepatopancreas were identified as target tissues involved in AHPND pathogenesis, our results indicated that peritrophin in peritrophic membrane has a crucial role in determining not only colonization of AHPND-causing bacteria but also their tissue distribution. As the interaction between LvPeritrophin (LvPT) and WSSV (white spot syndrome virus) is not well understood, we noted that LvPT expression was upregulated in shrimp stomach challenged with either WSSV or AHPND. In an in vitro pathogen binding assay, there was strong binding of recombinant LvPT WSSV and AHPND-causing V. parahaemolyticus, and various bacteria. Furthermore, dsRNA-mediated LvPT silencing inhibited WSSV gene expression and viral genome replication. However, downregulation of LvPT gene expression increased copies of AHPND-causing bacteria in shrimp digestive tract, and facilitated bacterial colonization in stomach. In conclusion, we speculated that LvPT might regulate bacterial colonization during AHPND, whereas in WSSV infection, LvPT silencing favored the host. Although recombinant LvPT had strong binding with WSSV, the precise role of LvPT in WSSV infection needs further investigation. These findings increased our understanding of host-pathogen interactions in AHPND and WSSV infection that can be applied in shrimp aquaculture for developing effective antibacterial and antiviral strategies.

Bile acid and bile acid transporters are involved in the pathogenesis of acute hepatopancreatic necrosis disease in white shrimp Litopenaeus vannamei.

Acute hepatopancreas necrosis disease is a recently emerged shrimp disease that is caused by virulent strains of Vibrio parahaemolyticus. Although AHPND poses a serious threat to the shrimp industry, particularly in Asia, its underlying pathogenic mechanisms are not well characterized. Since a previous transcriptomic study showed upregulation of the apical sodium bile acid transporter (LvASBT), our objective here was to explore the role of bile acids and bile acid transporters in AHPND infection. We confirmed that mRNA expression of LvASBT was upregulated in the stomach of AHPND-infected shrimps. Bile acid concentrations were also higher in the stomach of AHPND-infected shrimp and correlated with high expression of pVA plasmid and Pir toxins. In vitro assays showed that bile acids enhanced biofilm formation and increased the release of PirABvp toxins in AHPND-causing V. parahaemolyticus, while in vivo inhibition of LvASBT by GSK2330672 reduced the copy numbers of pVA plasmid, Pir toxin and reduced the amounts of bile acids in AHPND-infected shrimp stomach. Transcriptomics data for AHPND-causing V. parahaemolyticus treated with bile acids showed upregulation of various genes involved in membrane transport, RND efflux pumps and a bacterial secretion system. Taken together, our results show that AHPND-causing V. parahaemolyticus virulence is positively regulated by bile acids and that LvASBT and bile acids in shrimp stomach have important roles in AHPND pathogenesis.

Exploring the psychosocial morbidity of women undergoing chemotherapy for breast cancer in a post-war setting: experiences of Northern Sri Lankan women.

PURPOSE: A breast cancer diagnosis leads to considerable internal conflict and social disruption. Coping with breast cancer may be especially challenging where psychosocial services are not integrated to cancer care. This exploratory descriptive qualitative study delves into breast cancer-associated psychosocial morbidity among women diagnosed with breast cancer at a cancer centre in post-war northern Sri Lanka. METHODS: Fifteen women with non-metastatic breast cancer and treated with curative intent, who were undergoing or had completed adjuvant chemotherapy, were included in the study. Data were gathered through semi-structured interviews and thematically analysed. RESULTS: Aside from the immediate effects of chemotherapy, participants grappled with concerns of body image, social stigma, and dependency while straddling anxieties about the fate of their families and expenses on cancer care. Demonstrating remarkable strength and resilience, however, they drew on their families and communities for support in the absence of a formal system of psychosocial care. These women's narratives shed light on certain universal aspects of the breast cancer experience as well as its specificity in a region devastated by war, where cancer care is delivered with minimal resources. CONCLUSION: The findings underscore the need to invest in integrating psychosocial services to chronic illness care in low- and middle-income settings.

Neonatal Therapy Staffing in the United States and Relationships to Neonatal Intensive Care Unit Type and Location, Level of Acuity, and Population Factors.

OBJECTIVES: This study aimed to (1) estimate the total pool of neonatal therapists (occupational therapists, physical therapists, and speech-language pathologists who work in the neonatal intensive care unit [NICU]) and the average number represented in each U.S. based NICU, and (2) investigate the relationships between the number and type of neonatal therapy team members to NICU/hospital, population, and therapy factors. STUDY DESIGN: This study used several methods of data collection (surveys, phone calls, and web site searches) that were combined to establish a comprehensive list of factors across each NICU in the United States. RESULTS: We estimate that there are 2,333 full-time equivalent (FTE) positions designated to neonatal therapy coverage, with 4,232 neonatal therapists covering those FTEs. Among 564 NICUs with available neonatal therapy staffing data, 432 (76%) had a dedicated therapy team, 103 (18%) had pro re nata (as the circumstances arise; PRN) therapy coverage only, and 35 (6%) had no neonatal therapy team. Having a dedicated therapy team was more likely in level-IV (n = 112; 97%) and -III (n = 269; 83%) NICUs compared with level-II NICUs (n = 51; 42%; p < 0.001). Having a dedicated therapy team was related to having more NICU beds (p < 0.001), being part of a free-standing children's hospital or children's hospital within a hospital (p < 0.001), and being part of an academic medical center or community hospital (p < 0.001). Having a dedicated therapy team was more common in the Southeast, Midwest, Southwest, and West (p = 0.001) but was not related to the proportion of the community living in poverty or belonging to racial/ethnic minorities (p > 0.05). There was an average of 17 beds per neonatal therapy FTE, a good marker of therapy coverage based on NICU size. Three-hundred U.S. based NICUs (22%) had at least one Certified Neonatal Therapist (CNT) in early 2020, with CNT presence being more likely in higher acuity NICUs (59% of level-IV NICUs had at least one CNT). CONCLUSION: Understanding the composition of neonatal therapy teams at different hospitals across the U.S. can drive change to expand neonatal therapy services aimed at optimizing outcomes of high-risk infants and families. KEY POINTS: · We estimated that there are 4,232 neonatal therapists working in NICUs in the United States.. · Dedicated therapy teams for the NICU are more common in large, high acuity NICUs.. · An average of 17 beds per neonatal therapy FTE was observed.. · In 2020, 22% of NICUs had CNTs, and CNTs were more common in large and high acuity NICUs.. · Benchmarking neonatal therapy staffing can aid in expanding NICU therapy services where needed..

Shrimp SIRT1 activates of the WSSV IE1 promoter independently of the NF-κB binding site.

Since the mechanisms by which cellular factors modulate replication of the shrimp viral pathogen white spot syndrome virus (WSSV) are still largely unknown, here we consider the sirtuins, a family of NAD+-dependent protein deacetylases that are known to function as regulatory factors that activate or suppress viral transcription and replication in mammals. In particular, we focus on SIRT1 by isolating and characterizing LvSIRT1 from white shrimp (Litopenaeus vannamei) and investigating its involvement in WSSV infection. DsRNA-mediated gene silencing led to the expression of WSSV genes and the replication of genomic DNAs being significantly decreased in LvSIRT1-silenced shrimp. The deacetylase activity of LvSIRT1 was significantly induced at the early stage (2 hpi) and the genome replication stage (12 hpi) of WSSV replication, but decreased at the late stage of WSSV replication (24 hpi). Treatment with the SIRT1 activator resveratrol further suggested that LvSIRT1 activation increased the expression of several WSSV genes (IE1, VP28 and ICP11). Lastly, we used transfection and dual luciferase assays in Sf9 insect cells to show that while the overexpression of LvSIRT1 facilitates the promoter activity of WSSV IE1, this enhancement of WSSV IE1 expression is achieved by a transactivation pathway that is NF-κB-independent.

The chemerin knockout rat reveals chemerin dependence in female, but not male, experimental hypertension.

Measures of the adipokine chemerin are elevated in multiple cardiovascular diseases, including hypertension, but little mechanistic work has been done to implicate chemerin as being causative in such diseases. The chemerin knockout (KO) rat was created to test the hypothesis that removal of chemerin would reduce pressure in the normal and hypertensive state. Western analyses confirmed loss of chemerin in the plasma and tissues of the KO vs. wild-type (WT) rats. Chemerin concentration in plasma and tissues was lower in WT females than in WT males, as determined by Western analysis. Conscious male and female KO rats had modest differences in baseline measures vs. the WT that included systolic, diastolic, mean arterial and pulse pressures, and heart rate, all measured telemetrically. The mineralocorticoid deoxycorticosterone acetate (DOCA) and salt water, combined with uninephrectomy as a hypertensive stimulus, elevated mean and systolic blood pressures of the male KO higher than the male WT. By contrast, all pressures in the female KO were lower than their WT throughout DOCA-salt treatment. These results revealed an unexpected sex difference in chemerin expression and the ability of chemerin to modify blood pressure in response to a hypertensive challenge.-Watts, S. W., Darios, E. S., Mullick, A. E., Garver, H., Saunders, T. L., Hughes, E. D., Filipiak, W. E., Zeidler, M. G., McMullen, N., Sinal, C. J., Kumar, R. K., Ferland, D. J., Fink, G. D. The chemerin knockout rat reveals chemerin dependence in female, but not male, experimental hypertension.

Fenfluramine-induced PVAT-dependent contraction depends on norepinephrine and not serotonin.

Perivascular adipose tissue (PVAT) modulates vascular tone and altered PVAT function is observed in vascular diseases such as hypertension and atherosclerosis. We discovered that the PVAT surrounding rat thoracic aorta (RA) and the superior mesenteric artery (SMA) contain significant amounts of 5-hydroxytryptamine (5-HT). We hypothesized that the 5-HT contained within the PVAT is functional and vasoactive. Isolated tissue baths were used for isometric contractility studies and high performance liquid chromatography was used to quantitatively measure amines in the PVAT and release studies. The 5-HT releaser fenfluramine (10 nM-100 µM) was tested for its ability to contract arteries with and without PVAT. Contraction was reported as a percentage of the initial contraction to 10 µM phenylephrine. The RA with PVAT contracted to fenfluramine to a greater maximum (98 ± 10%) than RA without PVAT (24 ± 4%), while no difference in contraction of SMA to maximum fenfluramine with (78 ± 2%) and without (75 ± 6%) PVAT was observed. Contradicting our hypothesis, the maximum contraction of RA with PVAT to fenfluramine was diminished by the alpha-1 adrenoreceptor antagonist prazosin (100 nM; vehicle: 71 ± 4%, prazosin: 24 ± 2%) and the norepinephrine transporter (NET) inhibitor nisoxetine (1 µM; vehicle: 71 ± 4%, nisoxetine: 25 ± 4%) but not the 5-HT2A/2C receptor antagonist ketanserin (10 nM) or serotonin specific reuptake inhibitor fluoxetine (10 µM). To test if fenfluramine caused release of 5-HT or NE from PVAT, PVAT from RA was incubated with vehicle or fenfluramine (10 µM-10 mM), and amines released into the incubating buffer were quantified. A pronounced concentration-dependent NE-release (more than 5-HT) was observed. Collectively, this research illustrates the pharmacology of fenfluramine to primarily stimulate NE release (better than 5-HT) in a NET-dependent manner, leading to vasoconstriction. This adds additional support to PVAT as being an important reservoir of amines.