Mediating a host cell signaling pathway linked to overwinter mortality offers a promising therapeutic approach for improving bee health.

INTRODUCTION: Honey bees provides valuable pollination services for world food crops and wild flowering plants which are habitats of many animal species and remove carbon dioxide from the atmosphere, a powerful tool in the fight against climate change. Nevertheless, the honey bee population has been declining and the majority of colony losses occur during the winter. OBJECTIVES: The goal of this study was to understand the mechanisms underlying overwinter colony losses and develop novel therapeutic strategies for improving bee health. METHODS: First, pathogen prevalence in overwintering bees were screened between 2015 and 2018. Second, RNA sequencing (RNA-Seq) for transcriptional profiling of overwintering honey bees was conducted and qRT-PCR was performed to confirm the results of the differential expression of selected genes. Lastly, laboratory bioassays were conducted to measure the effects of cold challenges on bee survivorship and stress responses and to assess the effect of a novel medication for alleviating cold stress in honey bees. RESULTS: We identified that sirtuin signaling pathway is the most significantly enriched pathway among the down-regulated differentially expressed genes (DEGs) in overwintering diseased bees. Moreover, we showed that the expression of SIRT1 gene, a major sirtuin that regulates energy and immune metabolism, was significantly downregulated in bees merely exposed to cold challenges, linking cold stress with altered gene expression of SIRT1. Furthermore, we demonstrated that activation of SIRT1 gene expression by SRT1720, an activator of SIRT1 expression, could improve the physiology and extend the lifespan of cold-stressed bees. CONCLUSION: Our study suggests that increased energy consumption of overwintering bees for maintaining hive temperature reduces the allocation of energy toward immune functions, thus making the overwintering bees more susceptible to disease infections and leading to high winter colony losses. The novel information gained from this study provides a promising avenue for the development of therapeutic strategies for mitigating colony losses, both overwinter and annually.

Transferrin-mediated iron sequestration suggests a novel therapeutic strategy for controlling Nosema disease in the honey bee, Apis mellifera.

Nosemosis C, a Nosema disease caused by microsporidia parasite Nosema ceranae, is a significant disease burden of the European honey bee Apis mellifera which is one of the most economically important insect pollinators. Nevertheless, there is no effective treatment currently available for Nosema disease and the disease mechanisms underlying the pathological effects of N. ceranae infection in honey bees are poorly understood. Iron is an essential nutrient for growth and survival of hosts and pathogens alike. The iron tug-of-war between host and pathogen is a central battlefield at the host-pathogen interface which determines the outcome of an infection, however, has not been explored in honey bees. To fill the gap, we conducted a study to investigate the impact of N. ceranae infection on iron homeostasis in honey bees. The expression of transferrin, an iron binding and transporting protein that is one of the key players of iron homeostasis, in response to N. ceranae infection was analysed. Furthermore, the functional roles of transferrin in iron homeostasis and honey bee host immunity were characterized using an RNA interference (RNAi)-based method. The results showed that N. ceranae infection causes iron deficiency and upregulation of the A. mellifera transferrin (AmTsf) mRNA in honey bees, implying that higher expression of AmTsf allows N. ceranae to scavenge more iron from the host for its proliferation and survival. The suppressed expression levels of AmTsf via RNAi could lead to reduced N. ceranae transcription activity, alleviated iron loss, enhanced immunity, and improved survival of the infected bees. The intriguing multifunctionality of transferrin illustrated in this study is a significant contribution to the existing body of literature concerning iron homeostasis in insects. The uncovered functional role of transferrin on iron homeostasis, pathogen growth and honey bee's ability to mount immune responses may hold the key for the development of novel strategies to treat or prevent diseases in honey bees.

Pollen reverses decreased lifespan, altered nutritional metabolism and suppressed immunity in honey bees (Apis mellifera) treated with antibiotics.

Nutrition is involved in regulating multiple aspects of honey bee biology such as caste, immunity, lifespan, growth and behavioral development. Deformed wing virus (DWV) is a major pathogenic factor which threatens honey bee populations, and its replication is regulated by the nutrition status and immune response of honey bees. The alimentary canal of the honey bee is home to a diverse microbial community that provides essential nutrients and serves to bolster immune responses. However, to what extent gut bacteria affect honey bee nutrition metabolism and immunity with respect to DWV has not been investigated fully. In this study, newly emerged worker bees were subjected to four diets that contained (1) pollen, (2) pollen and antibiotics, (3) neither pollen nor antibiotics or (4) antibiotics alone. The expression level of two nutrition genes target of rapamycin (tor) and insulin like peptide (ilp1), one nutritional marker gene vitellogenin (vg), five major royal jellyprotein genes (mrjp1-5), one antimicrobial peptide regulating gene relish (rel), and DWV virus titer and its replication intermediate, negative RNA strand, were determined by qRT-PCR from the honey bees at 7 days post-antibiotic treatment. Additionally, honey bee head mass and survival rate were measured. We observed that antibiotics decreased the expression of tor and rel, and increased DWV titer and its replication activity. Expression of ilp1, mrjp1-5 and vg, and honey bee head mass were also reduced compared with bees on a pollen diet. Antibiotics also caused a significant drop in survivorship, which could be rescued by addition of pollen to the diet. Of importance, pollen could partially rescue the loss of vg and mrjp2 while also increasing the head mass of antibiotic-treated bees. Our results illuminate the roles of bacteria in honey bee nutrition, metabolism and immunity, which confer the ability to inhibit virus replication, extend honey bee lifespan and improve overall health.

New evidence showing that the destruction of gut bacteria by antibiotic treatment could increase the honey bee's vulnerability to Nosema infection.

It has become increasingly clear that gut bacteria play vital roles in the development, nutrition, immunity, and overall fitness of their eukaryotic hosts. We conducted the present study to investigate the effects of gut microbiota disruption on the honey bee's immune responses to infection by the microsporidian parasite Nosema ceranae. Newly emerged adult workers were collected and divided into four groups: Group I-no treatment; Group II-inoculated with N. ceranae, Group III-antibiotic treatment, and Group IV-antibiotic treatment after inoculation with N. ceranae. Our study showed that Nosema infection did not cause obvious disruption of the gut bacterial community as there was no significant difference in the density and composition of gut bacteria between Group I and Group II. However, the elimination of gut bacteria by antibiotic (Groups III and IV) negatively impacted the functioning of the honey bees' immune system as evidenced by the expression of genes encoding antimicrobial peptides abaecin, defensin1, and hymenoptaecin that showed the following ranking: Group I > Group II > Group III > Group IV. In addition, significantly higher Nosema levels were observed in Group IV than in Group II, suggesting that eliminating gut bacteria weakened immune function and made honey bees more susceptible to Nosema infection. Based on Group IV having displayed the highest mortality rate among the four experimental groups indicates that antibiotic treatment in combination with stress, associated with Nosema infection, significantly and negatively impacts honey bee survival. The present study adds new evidence that antibiotic treatment not only leads to the complex problem of antibiotic resistance but can impact honey bee disease resistance. Further studies aimed at specific components of the gut bacterial community will provide new insights into the roles of specific bacteria and possibly new approaches to improving bee health.

Marijuana and Listing for Heart Transplant: A Survey of Transplant Providers.

BACKGROUND: There is no consensus within the heart transplant community about whether patients who use marijuana should be eligible for transplant listing, but several states have passed legislation prohibiting marijuana-using patients from being denied transplant listing based on their use of the substance. METHODS AND RESULTS: We conducted an independent, voluntary, web-based survey of heart and lung transplant providers to assess current practice patterns and attitudes toward marijuana use in patients with advanced heart failure being considered for transplant. A total of 360 heart transplant providers responded from 26 countries. Nearly two thirds of respondents (n=222, 64.4%) supported listing patients with advanced, end-stage heart failure for transplant who use legal medical marijuana. Significantly, fewer respondents (n=96, 27.5%) supported transplant listing for patients using legal recreational marijuana. The majority of providers currently make patients eligible for transplantation after a period of abstinence from marijuana (n=241, 68.3%). There were no differences between the proportion of respondents supporting transplant listing after stratification by profession or country/region. Most (78.4%) survey respondents from states with laws prohibiting marijuana-using patients from being denied transplant listing reported denying all marijuana-using patients or mandating abstinence before transplant listing. CONCLUSIONS: The majority of heart and lung transplant providers in our study sample supports the listing of patients who use medical marijuana for transplant after a period of abstinence. Communication and collaboration between the medical community and legislative groups about marijuana use in transplant candidates is needed to ensure the best patient outcomes with the use of scarce donor organs.

Systemic spread and propagation of a plant-pathogenic virus in European honeybees, Apis mellifera.

UNLABELLED: Emerging and reemerging diseases that result from pathogen host shifts are a threat to the health of humans and their domesticates. RNA viruses have extremely high mutation rates and thus represent a significant source of these infectious diseases. In the present study, we showed that a plant-pathogenic RNA virus, tobacco ringspot virus (TRSV), could replicate and produce virions in honeybees, Apis mellifera, resulting in infections that were found throughout the entire body. Additionally, we showed that TRSV-infected individuals were continually present in some monitored colonies. While intracellular life cycle, species-level genetic variation, and pathogenesis of the virus in honeybee hosts remain to be determined, the increasing prevalence of TRSV in conjunction with other bee viruses from spring toward winter in infected colonies was associated with gradual decline of host populations and winter colony collapse, suggesting the negative impact of the virus on colony survival. Furthermore, we showed that TRSV was also found in ectoparasitic Varroa mites that feed on bee hemolymph, but in those instances the virus was restricted to the gastric cecum of Varroa mites, suggesting that Varroa mites may facilitate the spread of TRSV in bees but do not experience systemic invasion. Finally, our phylogenetic analysis revealed that TRSV isolates from bees, bee pollen, and Varroa mites clustered together, forming a monophyletic clade. The tree topology indicated that the TRSVs from arthropod hosts shared a common ancestor with those from plant hosts and subsequently evolved as a distinct lineage after transkingdom host alteration. This study represents a unique example of viruses with host ranges spanning both the plant and animal kingdoms. IMPORTANCE: Pathogen host shifts represent a major source of new infectious diseases. Here we provide evidence that a pollen-borne plant virus, tobacco ringspot virus (TRSV), also replicates in honeybees and that the virus systemically invades and replicates in different body parts. In addition, the virus was detected inside the body of parasitic Varroa mites, which consume bee hemolymph, suggesting that Varroa mites may play a role in facilitating the spread of the virus in bee colonies. This study represents the first evidence that honeybees exposed to virus-contaminated pollen could also be infected and raises awareness of potential risks of new viral disease emergence due to host shift events. About 5% of known plant viruses are pollen transmitted, and these are potential sources of future host-jumping viruses. The findings from this study showcase the need for increased surveillance for potential host-jumping events as an integrated part of insect pollinator management programs.

Failing the failing heart: a review of palliative care in heart failure.

Heart failure (HF) is the most common reason for hospital admission for patients older than 65 years. With an aging population and improving survival in heart failure patients, the number of people living with HF continues to grow. As this population increases, the importance of treating symptoms of fatigue, dyspnea, pain, and depression that diminish the quality of life in HF patients becomes increasingly important. Palliative care has been shown to help alleviate these symptoms and improve patients' satisfaction with the care they receive. Despite this growing body of evidence, palliative care consultation remains underutilized and is not standard practice in the management of HF. With an emphasis on communication, symptom management, and coordinated care, palliative care provides an integrated approach to support patients and families with chronic illnesses. Early communication with patients and families regarding the unpredictable nature of HF and the increased risk of sudden cardiac death enables discussions around advanced care directives, health care proxies, and deactivation of permanent pacemakers or implantable cardioverter defibrillators. Cardiologists and primary care physicians who are comfortable initiating these discussions are encouraged to do so; however, many fear destroying hope and are uncertain how to discuss end-of-life issues. Thus, in order to facilitate these discussions and establish an appropriate relationship, we recommend that patients and families be introduced to a palliative care team at the earliest appropriate time after diagnosis.

Acupuncture inhibits sympathetic activation during mental stress in advanced heart failure patients.

BACKGROUND: In heart failure (HF) patients, muscle sympathetic nerve activity is increased, and HF patients with the greatest sympathetic activation have the poorest prognosis. In animals, acupuncture is sympathoinhibitory, and the most profound sympathoinhibition occurs in animals with the highest resting sympathetic nerve activity. The purpose of this study was to test the hypothesis that acupuncture is sympathoinhibitory in humans with HF. METHODS AND RESULTS: Fifteen advanced HF patients underwent acute mental stress testing before and during (1) "real" acupuncture (n = 10), (2) non-acupoint acupuncture (n = 10), and (3) no-needle acupuncture control (n = 10). Muscle sympathetic nerve activity (MSNA) was recorded using peroneal microneurography. Resting MSNA was not different before and after acupuncture (52 +/- 22 versus 50 +/- 21 bursts/min, P = NS). During mental stress, SNA increased significantly. This increase was eliminated following real acupuncture (mean delta MSNA pre-acupuncture versus post-acupuncture: 149 +/- 171 versus -169 +/- 130, P =.03), but not after non-acupoint or no-needle acupuncture controls. The changes in blood pressure and heart rate during mental stress were not attenuated by real or control acupuncture. CONCLUSION: Acute acupuncture attenuates sympathoexcitation during mental stress in advanced HF patients.