Dermal Dive: An Overview of Cutaneous Wounding Techniques in Zebrafish.

Cutaneous wounds are common injuries that affect millions of people around the world. In vulnerable populations such as the elderly and those with diabetes, defects in wound healing can lead to the development of chronic open wounds. Although mammalian models are commonly used to study cutaneous wound healing, the challenges of in vivo imaging in mammals have hampered detailed observation of cell coordination and cell signaling during wound healing. The zebrafish is becoming increasingly popular for studying cutaneous wound healing owing to its genetic accessibility, suitability for experimental manipulation, and the ability to perform live, in vivo imaging with cellular or even subcellular resolution. In this paper, we review some of the techniques that have been developed for eliciting cutaneous wounds in the zebrafish, including an economical method we recently developed using a rotary tool that generates consistent and reproducible full-thickness wounds. Combined with the thousands of transgenic lines and experimental assays available in zebrafish, the ability to generate reproducible cutaneous wounds makes it possible to study key cellular and molecular events during wound healing using this powerful experimental model organism.

Live Imaging of Cutaneous Wound Healing after Rotary Tool Injury in Zebrafish.

Cutaneous wounds are common afflictions that follow a stereotypical healing process involving hemostasis, inflammation, proliferation, and remodeling phases. In the elderly and those suffering from vascular or metabolic diseases, poor healing after cutaneous injuries can lead to open chronic wounds susceptible to infection. The discovery of new therapeutic strategies to improve this defective wound healing requires a better understanding of the cellular behaviors and molecular mechanisms that drive the different phases of wound healing and how these are altered with age or disease. The zebrafish provides an ideal model for visualization and experimental manipulation of the cellular and molecular events during wound healing in the context of an intact, living vertebrate. To facilitate studies of cutaneous wound healing in zebrafish, we have developed an inexpensive, simple, and effective method for generating reproducible cutaneous injuries in adult zebrafish using a rotary tool. We demonstrate that our injury system can be used in combination with high-resolution live imaging to monitor skin re-epithelialization, immune cell recruitment and activation, and vessel regrowth in the same animal over time. This injury system provides a valuable experimental platform to study key cellular and molecular events during wound healing in vivo with unprecedented resolution.

Pathway to Independence: the future of developmental biology.

In 2022, Development launched its Pathway to Independence (PI) Programme, aimed at supporting postdocs as they transition to their first independent position. We selected eight talented researchers as the first cohort of PI Fellows. In this article, each of our Fellows provides their perspective on the future of their field. Together, they paint an exciting picture of the current state of and open questions in developmental biology.

Live Imaging of the Drosophila Testis Stem Cell Niche.

Live imaging of adult tissue stem cell niches provides key insights into the dynamic behavior of stem cells, their differentiating progeny, and their neighboring support cells, but few niches are amenable to this approach. Here, we discuss a technique for long-term live imaging of the Drosophila testis stem cell niche. Culturing whole testes ex vivo for up to 18 h allows for tracking of cell-type-specific behaviors under normal and various chemically or genetically modified conditions. Fixing and staining tissues after live imaging allows for the molecular confirmation of cell identity and behavior. By using live imaging in intact niches, we can better uncover the cellular and molecular mechanisms that regulate stem cell function in vivo.

COMMunity of Practice And Safety Support for Navigating Pain (COMPASS-NP): study protocol for a randomized controlled trial with home care workers.

BACKGROUND: Chronic pain is a prevalent and costly problem that often has occupational origins. Home care workers (HCWs) are at high risk for work-related injuries, pain, and disability. Current treatments for chronic pain emphasize medications, which are an inadequate stand-alone treatment and can produce significant adverse effects. METHODS: In this translational study, we will adapt an established work-based injury prevention and health promotion program (COMmunity of Practice And Safety Support: COMPASS) to address the needs of HCWs experiencing chronic pain. COMPASS employs peer-led, scripted group meetings that include educational content, activities, goal setting, and structured social support. The translated intervention, named COMPASS for Navigating Pain (COMPASS-NP), will be delivered in an online group format. Safety protections will be strengthened through an ergonomic self-assessment and vouchers for purchasing ergonomic tools. Educational content will integrate a self-management approach to chronic pain using proven cognitive-behavioral therapy (CBT) principles. We will use a mixed-methods hybrid type 2 evaluation approach to assess effectiveness and implementation. A cluster-randomized waitlist control design will involve 14 groups of 10 HCWs (n = 140) recruited from Washington, Oregon, and Idaho. Half of the groups will be randomly selected to complete the intervention during the first 10 weeks, while the waitlist groups serve as controls. During weeks 10-20, the waitlist groups will complete the intervention while the original intervention groups complete a follow-up period without further intervention. Our primary hypothesis is that COMPASS-NP will reduce pain interference with work and life. Secondary outcomes include injury and pain prevention behaviors, pain severity, changes in medication use, risk for opioid misuse, well-being, physical activity, and sleep. Qualitative data, including phone interviews with group facilitators and organizational partners, will evaluate the implementation and guide dissemination. DISCUSSION: The results will advance the use and knowledge of secondary prevention interventions such as ergonomic tools and cognitive behavior therapy, to reduce injury, pain, and disability and to encourage appropriate uses of analgesic medications among HCWs. TRIAL REGISTRATION: ClinicalTrials.gov NCT05492903. Registered on 08 August 2022.

Primary Prevention of Weight Gain Among New Bus Operators: Results of the "Success & Health Impacts For Transit operators during Onboarding" (SHIFT Onboard) Pilot Study.

OBJECTIVE: This study aimed to test the feasibility and efficacy of an enhanced onboarding intervention to prevent weight gain and support the early job success of new bus operators. METHODS: Control participants ( n = 9) completed usual practice new employee training and onboarding. Intervention participants ( n = 14) completed five supplemental trainings and four online challenges during their first year. Primary outcomes were body weight, dietary behaviors, physical activity, and sleep duration/quality. Early job success was evaluated with measures of newcomer adjustment. RESULTS: The difference between intervention and control participants in body weight change at 12-month was -6.71 lb (Cohen's d = -1.35). Differences in health behavior changes were mixed, but newcomer adjustment changes favored the intervention group. CONCLUSIONS: Results support the feasibility of enhanced onboarding for bus operators to prevent worsening health while simultaneously advancing their success as new employees.

Activation of the EGFR/MAPK pathway drives transdifferentiation of quiescent niche cells to stem cells in the Drosophila testis niche.

Adult stem cells are maintained in niches, specialized microenvironments that regulate their self-renewal and differentiation. In the adult Drosophila testis stem cell niche, somatic hub cells produce signals that regulate adjacent germline stem cells (GSCs) and somatic cyst stem cells (CySCs). Hub cells are normally quiescent, but after complete genetic ablation of CySCs, they can proliferate and transdifferentiate into new CySCs. Here we find that Epidermal growth factor receptor (EGFR) signaling is upregulated in hub cells after CySC ablation and that the ability of testes to recover from ablation is inhibited by reduced EGFR signaling. In addition, activation of the EGFR pathway in hub cells is sufficient to induce their proliferation and transdifferentiation into CySCs. We propose that EGFR signaling, which is normally required in adult cyst cells, is actively inhibited in adult hub cells to maintain their fate but is repurposed to drive stem cell regeneration after CySC ablation.

The Impact of COVID-19 on Transit Workers: Perceptions of Employer Responses and Associations with Health Factors.

COVID-19 has had a substantial impact on transit workers' lives, especially among public-facing vehicle operators. The current project examined relationships between workers' knowledge and perceptions of their employer's COVID-19 safety responses, job attitudes, and health. We surveyed transit workers (N = 174) between July and August 2020 and followed up 3 months later. Fifty-seven workers responded to the follow-up survey. Surveys addressed workers' knowledge and perceptions of their employer implementing Centers for Disease Control and Prevention (CDC)-recommended COVID-19 safety responses, COVID-19 risk perceptions, job attitudes, and health factors. Employees reported knowledge of their employer implementing ~8 of 12 CDC-recommended responses. The most reported response was informational poster placements; the least reported was designating a point-person for COVID-19 concerns. Significant associations were found between knowledge of employer safety responses and lower COVID-19 risk perceptions, better job attitudes, and greater mental and global health. Operators (i.e. public-facing workers) reported worse perceptions of employer responses, and higher COVID-19 risk perceptions, work stress, and turnover intentions, compared with non-operators. A time-lagged panel model found that COVID-19 risk perceptions significantly mediated the relationship between public-facing work status and follow-up depression, anxiety, stress, and global health. Results reveal opportunities for transit authorities to broaden and better communicate their responses to emergent occupational safety and health crises.

To be or not to be: endothelial cell plasticity in development, repair, and disease.

Endothelial cells display an extraordinary plasticity both during development and throughout adult life. During early development, endothelial cells assume arterial, venous, or lymphatic identity, while selected endothelial cells undergo additional fate changes to become hematopoietic progenitor, cardiac valve, and other cell types. Adult endothelial cells are some of the longest-lived cells in the body and their participation as stable components of the vascular wall is critical for the proper function of both the circulatory and lymphatic systems, yet these cells also display a remarkable capacity to undergo changes in their differentiated identity during injury, disease, and even normal physiological changes in the vasculature. Here, we discuss how endothelial cells become specified during development as arterial, venous, or lymphatic endothelial cells or convert into hematopoietic stem and progenitor cells or cardiac valve cells. We compare findings from in vitro and in vivo studies with a focus on the zebrafish as a valuable model for exploring the signaling pathways and environmental cues that drive these transitions. We also discuss how endothelial plasticity can aid in revascularization and repair of tissue after damage- but may have detrimental consequences under disease conditions. By better understanding endothelial plasticity and the mechanisms underlying endothelial fate transitions, we can begin to explore new therapeutic avenues.

Exploring biopsychosocial correlates of pain, pain management strategies, and risk for opioid misuse among home care workers in Washington State.

Home care workers (HCWs) are at high risk for musculoskeletal pain and injury, and they are an important population for pain management research and intervention. The purpose of this study was to gather novel data on HCWs' work characteristics, pain experiences, pain management strategies, and risk for opioid misuse. A survey invitation was e-mailed to a random sub-sample of HCWs in Washington State, and 421 responded. Over half (54.2%) reported chronic or currently elevated pain. Pharmacological pain management strategies were used by 67.3% of all respondents with 4.8% reporting prescription opioid use. Biopsychosocial factors like injuries, interpersonal conflict, financial strain, and anxiety were associated with increased opioid misuse risk. Multimodal primary and secondary interventions are recommended to improve HCWs' pain management.

Does Experiencing an Injury Claim Impact Small Construction Company Leaders' Participation in a Fall Protection Survey?

OBJECTIVES: Workers in small and medium residential construction companies (≤50 employees) have a high risk of fall-related fatality or disability. However, little is known about effective ways to engage with this subsector for research and training. We tested whether insurance-documented fall-related claims during the past 12 months and lower familiarity with equipment motivated companies' representatives to engage with a fall protection survey. METHODS: Oregon's largest workers compensation insurer drew a random anonymous sample of small and medium residential construction that did (n = 197) and did not (n = 195) have a recent fall-related claim. Samples were stratified by size, trade, and region. Company representatives were emailed a 34-item questionnaire about equipment familiarity to enter a raffle to win fall-prevention equipment. We coded survey engagement binarily, indicating whether a participant completed at least half of the survey. Familiarity with 10 pieces of equipment was measured with a scale from 0 (never seen it) to 3 (use it frequently) points. RESULTS: The survey was initiated by 88 out of 392 representatives (22.4% response rate). Of those, 63 representatives provided the company identifier which was needed to establish claim status. Survey engagement was higher among representatives from companies with claims compared with those without (57.6 versus 42.4%, P = 0.16). Equipment familiarity was lower among company representatives with lower survey engagement (1.15 versus 1.56, P < 0.05). CONCLUSIONS: The survey had a relatively encouraging response rate for a hard-to-reach sector. The large but not statistically significant difference in survey engagement rates suggests that adverse events motivate companies to engage with fall protection research. Low equipment familiarity in the sample substantiates the need to identify effective engagement methods for fall protection practices.

Retinoblastoma Intrinsically Regulates Niche Cell Quiescence, Identity, and Niche Number in the Adult Drosophila Testis.

Homeostasis in adult tissues depends on the precise regulation of stem cells and their surrounding microenvironments, or niches. Here, we show that the cell cycle inhibitor and tumor suppressor Retinoblastoma (RB) is a critical regulator of niche cells in the Drosophila testis. The testis contains a single niche, composed of somatic hub cells, that signals to adjacent germline and somatic stem cells. Hub cells are normally quiescent, but knockdown of the RB homolog Rbf in these cells causes them to proliferate and convert to somatic stem cells. Over time, mutant hub cell clusters enlarge and split apart, forming ectopic hubs surrounded by active stem cells. Furthermore, we show that Rbf's ability to restrict niche number depends on the transcription factors E2F and Escargot and the adhesion molecule E-cadherin. Together this work reveals how precise modulation of niche cells, not only the stem cells they support, can drive regeneration and disease.

Live Imaging of the Drosophila Testis Stem Cell Niche.

Live imaging of adult tissue stem cell niches provides key insights into the dynamic behavior of stem cells, their differentiating progeny, and their neighboring support cells, but few niches are amenable to this approach. Here we discuss a technique for long-term live imaging of the Drosophila testis stem cell niche. Culturing whole testes ex vivo for up to 12.5 h allows for tracking of cell-type specific behaviors under normal and various chemically or genetically modified conditions. Fixing and staining tissues after live imaging allows for the molecular confirmation of cell identity and behavior. Utilization of live imaging in intact niches will facilitate further understanding of the cellular and molecular mechanisms that regulate stem cell function in vivo.

Genetics of gonadal stem cell renewal.

Stem cells are necessary for the maintenance of many adult tissues. Signals within the stem cell microenvironment, or niche, regulate the self-renewal and differentiation capability of these cells. Misregulation of these signals through mutation or damage can lead to overgrowth or depletion of different stem cell pools. In this review, we focus on the Drosophila testis and ovary, both of which contain well-defined niches, as well as the mouse testis, which has become a more approachable stem cell system with recent technical advances. We discuss the signals that regulate gonadal stem cells in their niches, how these signals mediate self-renewal and differentiation under homeostatic conditions, and how stress, whether from mutations or damage, can cause changes in cell fate and drive stem cell competition.

Coordinate regulation of stem cell competition by Slit-Robo and JAK-STAT signaling in the Drosophila testis.

Stem cells in tissues reside in and receive signals from local microenvironments called niches. Understanding how multiple signals within niches integrate to control stem cell function is challenging. The Drosophila testis stem cell niche consists of somatic hub cells that maintain both germline stem cells and somatic cyst stem cells (CySCs). Here, we show a role for the axon guidance pathway Slit-Roundabout (Robo) in the testis niche. The ligand Slit is expressed specifically in hub cells while its receptor, Roundabout 2 (Robo2), is required in CySCs in order for them to compete for occupancy in the niche. CySCs also require the Slit-Robo effector Abelson tyrosine kinase (Abl) to prevent over-adhesion of CySCs to the niche, and CySCs mutant for Abl outcompete wild type CySCs for niche occupancy. Both Robo2 and Abl phenotypes can be rescued through modulation of adherens junction components, suggesting that the two work together to balance CySC adhesion levels. Interestingly, expression of Robo2 requires JAK-STAT signaling, an important maintenance pathway for both germline and cyst stem cells in the testis. Our work indicates that Slit-Robo signaling affects stem cell function downstream of the JAK-STAT pathway by controlling the ability of stem cells to compete for occupancy in their niche.

Associations between Variation in X Chromosome Male Reproductive Genes and Sperm Competitive Ability in Drosophila melanogaster.

Variation in reproductive success has long been thought to be mediated in part by genes encoding seminal proteins. Here we explore the effect on male reproductive phenotypes of X-linked polymorphisms, a chromosome that is depauperate in genes encoding seminal proteins. Using 57 X chromosome substitution lines, sperm competition was tested both when the males from the wild-extracted line were the first to mate ("defense" crosses), followed by a tester male, and when extracted-line males were the second to mate, after a tester male ("offfense" crosses). We scored the proportion of progeny sired by each male, the fecundity, the remating rate and refractoriness to remating, and tested the significance of variation among lines. Eleven candidate genes were chosen based on previous studies, and portions of these genes were sequenced in all 57 lines. A total of 131 polymorphisms were tested for associations with the reproductive phenotypes using linear models. Nine polymorphisms in 4 genes were found to show significant associations (at a 5% FDR). Overall, it appears that the X chromosomes harbor abundant variation in sperm competition, especially considering the paucity of seminal protein genes. This suggests that much of the male reproductive variation lies outside of genes that encode seminal proteins.