Liposome-Mediated Drug Delivery in Larval Zebrafish to Manipulate Macrophage Function.

Chemical interventions are regularly used to examine and manipulate macrophage function in larval zebrafish. Given chemicals are typically administered by simple immersion or injection, it is not possible to resolve whether their impact on macrophage function is direct or indirect. Liposomes provide an attractive strategy to target drugs to specific cellular compartments, including macrophages. As an example, injecting liposomal clodronate into animal models, including zebrafish, is routinely used to deliver toxic levels of clodronate specifically to macrophages for targeted cell ablation. Here we show that liposomes can also target the delivery of drugs to zebrafish macrophages to selectively manipulate their function. We utilized the drugs etomoxir (a fatty acid oxidation inhibitor) and MitoTEMPO (a scavenger of mitochondrial reactive oxygen species [mROS]), that we have previously shown, through free drug delivery, suppress monosodium urate (MSU) crystal-driven macrophage activation. We generated poloxamer 188 modified liposomes that were readily phagocytosed by macrophages, but not by neutrophils. Loading these liposomes with etomoxir or MitoTEMPO and injecting into larvae suppressed macrophage activation in response to MSU crystals, as evidenced by proinflammatory cytokine expression and macrophage-driven neutrophil recruitment. This work reveals the utility of packaging drugs into liposomes as a strategy to selectively manipulate macrophage function.

Compensatory growth renders Tcf7l1a dispensable for eye formation despite its requirement in eye field specification.

The vertebrate eye originates from the eye field, a domain of cells specified by a small number of transcription factors. In this study, we show that Tcf7l1a is one such transcription factor that acts cell-autonomously to specify the eye field in zebrafish. Despite the much-reduced eye field in tcf7l1a mutants, these fish develop normal eyes revealing a striking ability of the eye to recover from a severe early phenotype. This robustness is not mediated through genetic compensation at neural plate stage; instead, the smaller optic vesicle of tcf7l1a mutants shows delayed neurogenesis and continues to grow until it achieves approximately normal size. Although the developing eye is robust to the lack of Tcf7l1a function, it is sensitised to the effects of additional mutations. In support of this, a forward genetic screen identified mutations in hesx1, cct5 and gdf6a, which give synthetically enhanced eye specification or growth phenotypes when in combination with the tcf7l1a mutation.

Blocking fatty acid-fueled mROS production within macrophages alleviates acute gouty inflammation.

Gout is the most common inflammatory arthritis affecting men. Acute gouty inflammation is triggered by monosodium urate (MSU) crystal deposition in and around joints that activates macrophages into a proinflammatory state, resulting in neutrophil recruitment. A complete understanding of how MSU crystals activate macrophages in vivo has been difficult because of limitations of live imaging this process in traditional animal models. By live imaging the macrophage and neutrophil response to MSU crystals within an intact host (larval zebrafish), we reveal that macrophage activation requires mitochondrial ROS (mROS) generated through fatty acid oxidation. This mitochondrial source of ROS contributes to NF-κB-driven production of IL-1ß and TNF-α, which promote neutrophil recruitment. We demonstrate the therapeutic utility of this discovery by showing that this mechanism is conserved in human macrophages and, via pharmacologic blockade, that it contributes to neutrophil recruitment in a mouse model of acute gouty inflammation. To our knowledge, this study is the first to uncover an immunometabolic mechanism of macrophage activation that operates during acute gouty inflammation. Targeting this pathway holds promise in the management of gout and, potentially, other macrophage-driven diseases.

Antagonism between Gdf6a and retinoic acid pathways controls timing of retinal neurogenesis and growth of the eye in zebrafish.

Maintaining neurogenesis in growing tissues requires a tight balance between progenitor cell proliferation and differentiation. In the zebrafish retina, neuronal differentiation proceeds in two stages with embryonic retinal progenitor cells (RPCs) of the central retina accounting for the first rounds of differentiation, and stem cells from the ciliary marginal zone (CMZ) being responsible for late neurogenesis and growth of the eye. In this study, we analyse two mutants with small eyes that display defects during both early and late phases of retinal neurogenesis. These mutants carry lesions in gdf6a, a gene encoding a BMP family member previously implicated in dorsoventral patterning of the eye. We show that gdf6a mutant eyes exhibit expanded retinoic acid (RA) signalling and demonstrate that exogenous activation of this pathway in wild-type eyes inhibits retinal growth, generating small eyes with a reduced CMZ and fewer proliferating progenitors, similar to gdf6a mutants. We provide evidence that RA regulates the timing of RPC differentiation by promoting cell cycle exit. Furthermore, reducing RA signalling in gdf6a mutants re-establishes appropriate timing of embryonic retinal neurogenesis and restores putative stem and progenitor cell populations in the CMZ. Together, our results support a model in which dorsally expressed gdf6a limits RA pathway activity to control the transition from proliferation to differentiation in the growing eye.

Repositioning drugs for inflammatory disease - fishing for new anti-inflammatory agents.

Inflammation is an important and appropriate host response to infection or injury. However, dysregulation of this response, with resulting persistent or inappropriate inflammation, underlies a broad range of pathological processes, from inflammatory dermatoses to type 2 diabetes and cancer. As such, identifying new drugs to suppress inflammation is an area of intense interest. Despite notable successes, there still exists an unmet need for new effective therapeutic approaches to treat inflammation. Traditional drug discovery, including structure-based drug design, have largely fallen short of satisfying this unmet need. With faster development times and reduced safety and pharmacokinetic uncertainty, drug repositioning - the process of finding new uses for existing drugs - is emerging as an alternative strategy to traditional drug design that promises an improved risk-reward trade-off. Using a zebrafish in vivo neutrophil migration assay, we undertook a drug repositioning screen to identify unknown anti-inflammatory activities for known drugs. By interrogating a library of 1280 approved drugs for their ability to suppress the recruitment of neutrophils to tail fin injury, we identified a number of drugs with significant anti-inflammatory activity that have not previously been characterized as general anti-inflammatories. Importantly, we reveal that the ten most potent repositioned drugs from our zebrafish screen displayed conserved anti-inflammatory activity in a mouse model of skin inflammation (atopic dermatitis). This study provides compelling evidence that exploiting the zebrafish as an in vivo drug repositioning platform holds promise as a strategy to reveal new anti-inflammatory activities for existing drugs.

Adapting collaborative depression care for public community long-term care: using research-practice partnerships.

This manuscript details potential benefits for using a research-practice partnership to adapt collaborative depression care for public community long-term care agencies serving older adults. We used sequential, multi-phase, and mixed methods approaches for documenting the process of adaptation within a case study. Systematic adaptation strategies are described, such as leveraging long-term research-practice collaborations, consulting with multiple stakeholders across all levels and disciplines, and balancing demands to monitor treatment fidelity, clinical outcomes, and implementation results. These examples demonstrate that researchers interested in implementation science need skills to negotiate the competing demands that arise from both the research and practice settings.

Work engagement, moral distress, education level, and critical reflective practice in intensive care nurses.

AIM: The purpose of this study was to examine how nurses' moral distress, education level, and critical reflective practice (CRP) related to their work engagement. The study is relevant to nursing, given registered nurse (RN) documented experiences of job-related distress and work dissatisfaction, and the nursing shortage crisis. A better understanding of factors that may enhance RN work engagement is needed. METHODS: A non-experimental, descriptive, correlational design was used to examine the relationships among four variables: moral distress, education level, CRP, and work engagement. The sample included 28 intensive care unit RNs from three separate ICUs in a 355-bed Southwest magnet-designated hospital. RESULTS: There was a positive direct relationship between CRP and work engagement, a negative direct relationship between moral distress and work engagement, and CRP and moral distress, together, explained 47% of the variance in work engagement. Additionally, in the neonatal intensive care unit, a positive direct relationship between increased educational level and CRP was identified, with a suggested negative relationship between increased education level and moral distress. IMPLICATIONS: Strategies to promote CRP and reduce moral distress are recommended, to promote RN work engagement. Additionally, further study on the role of education in nurses' work engagement is recommended.

A paradigm for the production of practice-based knowledge.

AIM: The aim of this paper was to explore trends, arguments and issues surrounding knowledge production and nursing practice, and to propose a paradigm of practice-based knowledge along with strategies to promote theory-based knowledge development in practice. BACKGROUND: Practice-based knowledge has been marginalized in the current practice and research paradigms. Several reasons for this are presented, some of which may be addressed to facilitate a more inclusive approach to knowledge that can potentially advance patient care and the discipline. EVALUATION: Classic and contemporary scholarly sources in nursing, philosophy, education, social sciences and other areas were critically reviewed and applied to support the argument and propose a paradigm of practice-based knowledge production. KEY ISSUES: A key point identified in the paper is that theory, meaning conceptualizations at all levels of abstraction, is an important tool of knowledge development in nursing practice as it is in traditional research. Conclusions Various strategies exist that can be employed to promote development and use of practice-based knowledge in the clinical setting. The strategies are innovative yet practical, and require the support and encouragement of nursing management for their successful implementation. IMPLICATIONS FOR NURSING MANAGEMENT: Nursing managers can influence if not facilitate all of the strategies to promote practice-based knowledge development identified in the paper. These efforts could give voice to the caregiver's knowledge and, in turn, enhance patient care and the satisfaction and retention of nurses.

Depression in public community long-term care: implications for intervention development.

The objective of this paper is to increase understanding of geriatric depression in the public community long-term care system to guide intervention development. Protocols included screening 1,170 new clients of a public community long-term care agency and interviewing all clients with major, dysthymia, or subthreshold depression (n = 299) and a randomly selected subset of nondepressed older adults (n = 315) at baseline, 6-month, and 1 year. Six percent had major depression, one-half of a percent had dysthymia only, and another 19% had subthreshold depression. Over the year observation period, 40% were persistently depressed; 32% were assessed as depressed only at the first observation; and the remainder was intermittently depressed. There were high levels of comorbid medical, functional, and psychosocial conditions. Mental health service use was low, and clients reported attitudinal and other barriers to depression treatment. Findings suggest the need for universal screening for depression with some strategies for triaging the most severely and persistently depressed for treatment. Although there will be challenges to the development of depression interventions, the public community long-term care system has high potential to assist vulnerable older adults receive help with depression.

Notation of depression in case records of older adults in community long-term care.

Although significant numbers of social service clients experience mental health problems, virtually no research has examined the responsiveness of social service agencies to mental disorder. This article examines the extent to which client depression is reflected in records of a public social service agency, community long-term care (CLTC). Researchers assessed new, consenting CLTC clients for depression using standardized research criteria in a telephone interview. Agency case records were abstracted to determine the extent to which client depression was noted. Sensitivity and specificity of depression notation were 25.21 percent and 92.80 percent, respectively, indicating that agency records reflected depression for about one in four clients meeting depression criteria. Factors associated with accurate depression notation included cognitive impairments, low social support, psychotropic medications, and mental health treatment. The depression notation rates found are comparable to those in medical settings. Structured screening and assessment might enhance detection of mental disorder for social service clients.

Incorporating leadership knowledge and skills into the dental education community.

Leadership has been studied for the past four decades with an emphasis upon leadership and the transformation of various cultures, especially within the private sector. It is also becoming evident that leaders and leadership skills are often derived from core personal values and perceptions of what is and what could be. This summary describes an eleven-week selective course termed "Dean's Leadership Course" at the School of Dentistry at the University of Southern California. This selective course (a non-credit elective learning opportunity outside the formal curriculum) recruits a modest team of learners consisting of faculty, staff, and students and approaches leadership within the context of a "learning organization" coupled with case-based and problem-based learning. At the conclusion of this eleven-week course, participants are granted continuing education credit. This summary encourages others in dental education to consider the compelling opportunity to nurture and cultivate leadership within the university dental school environs.