Interleukin-4 Receptor α Signaling in Myeloid Cells Controls Collagen Fibril Assembly in Skin Repair

Activation of the immune response during injury is a critical early event that determines whether the outcome of tissue restoration is regeneration or replacement of the damaged tissue with a scar. The mechanisms by which immune signals control these fundamentally different regenerative pathways are largely unknown. We have demonstrated that, during skin repair in mice, interleukin-4 receptor α (IL-4Rα)-dependent macrophage activation controlled collagen fibril assembly and that this process was important for effective repair while having adverse pro-fibrotic effects. We identified Relm-α as one important player in the pathway from IL-4Rα signaling in macrophages to the induction of lysyl hydroxylase 2 (LH2), an enzyme that directs persistent pro-fibrotic collagen cross-links, in fibroblasts. Notably, Relm-β induced LH2 in human fibroblasts, and expression of both factors was increased in lipodermatosclerosis, a condition of excessive human skin fibrosis. Collectively, our findings provide mechanistic insights into the link between type 2 immunity and initiation of pro-fibrotic pathways.

Integrating the thematic approach into information literacy courses

Purpose

– The purpose of this paper is to review selected publications in library-related literature and discuss the thematic approach to course design in colleges and universities and how it has been implemented into information literacy (IL) courses.

Design/methodology/approach

– A literature review of peer-reviewed journals, professional journals, magazines and blogs contextualizes the thematic approach to instruction at the college and university levels. Search terms included “thematic approach”, “thematic approach in education” and “theme-based instruction”; the search was restricted to articles published in the past 20 years.

Findings

– In addition to the IL courses, thematic-based instruction has been used in biology, chemistry, English, French literature, history, mathematics, philosophy and sociology courses in college and university campuses. While instructors report that the thematic approach enhances student learning, few studies have directly tested the impact. No studies have been published within the library science literature.

Originality/value

– Thematic approach is a newer concept in the world of IL instruction. While many professional journal articles and blog posts provide in-depth case studies of how thematic-based instruction has been implemented, this article draws from all disciplines and features a succinct summary of what works, what does not work and how to best implement a thematic approach in an IL course.

p53 and TAp63 promote keratinocyte proliferation and differentiation in breeding tubercles of the zebrafish

p63 is a multi-isoform member of the p53 family of transcription factors. There is compelling genetic evidence that ΔNp63 isoforms are needed for keratinocyte proliferation and stemness in the developing vertebrate epidermis. However, the role of TAp63 isoforms is not fully understood, and TAp63 knockout mice display normal epidermal development. Here, we show that zebrafish mutants specifically lacking TAp63 isoforms, or p53, display compromised development of breeding tubercles, epidermal appendages which according to our analyses display more advanced stratification and keratinization than regular epidermis, including continuous desquamation and renewal of superficial cells by derivatives of basal keratinocytes. Defects are further enhanced in TAp63/p53 double mutants, pointing to partially redundant roles of the two related factors. Molecular analyses, treatments with chemical inhibitors and epistasis studies further reveal the existence of a linear TAp63/p53->Notch->caspase 3 pathway required both for enhanced proliferation of keratinocytes at the base of the tubercles and their subsequent differentiation in upper layers. Together, these studies identify the zebrafish breeding tubercles as specific epidermal structures sharing crucial features with the cornified mammalian epidermis. In addition, they unravel essential roles of TAp63 and p53 to promote both keratinocyte proliferation and their terminal differentiation by promoting Notch signalling and caspase 3 activity, ensuring formation and proper homeostasis of this self-renewing stratified epithelium.

The mammalian epidermis is a stratified self-renewing epithelium, in which cell loss at the surface is properly balanced by cell proliferation in basal layers to ensure tissue homeostasis. But how is this balance genetically controlled? Here, we address this question in zebrafish breeding tubercles, epidermal appendages in which keratinocytes undergo more advanced differentiation processes than in regular fish epidermis, sharing crucial features with the cornified mammalian skin. We identify a linear pathway consisting of the transcription factor p53 and its close relative TAp63, which activate Notch signalling and thereby caspase 3 to promote terminal differentiation and eventual shedding of keratinocytes in upper tubercle layers, while at the same time employing non-cell autonomous mechanisms to promote keratinocyte proliferation at the tubercle base, thereby ensuring proper development and homeostasis of this self-renewing tissue. Such a two-fold function of the pathway is consistent with the formerly reported dual role of a caspase during wing regeneration in the fruitfly. Our findings will help to better understand the seemingly contrary effects described for TAp63 in different mammalian systems, while demonstrating partial functional redundancy between p53 and TAp63 during epidermal development in fish.

Mutations in the interleukin receptor IL11RA cause autosomal recessive Crouzon-like craniosynostosis

We have characterized a novel autosomal recessive Crouzon-like craniosynostosis syndrome in a 12-affected member family from Antakya, Turkey, the presenting features of which include: multiple suture synostosis, midface hypoplasia, variable degree of exophthalmos, relative prognathism, a beaked nose, and conductive hearing loss. Homozygosity mapping followed by targeted next-generation sequencing identified a c.479+6T>G mutation in the interleukin 11 receptor alpha gene (IL11RA) on chromosome 9p21. This donor splice-site mutation leads to a high percentage of aberrant IL11RA mRNA transcripts in an affected individual and altered mRNA splicing determined by in vitro exon trapping. An extended IL11RA mutation screen was performed in a cohort of 79 patients with an initial clinical diagnosis of Crouzon syndrome, pansynostosis, or unclassified syndromic craniosynostosis. We identified mutations segregating with the disease in five families: a German patient of Turkish origin and a Turkish family with three affected sibs all of whom were homozygous for the previously identified IL11RA c.479+6T>G mutation; a family with pansynostosis with compound heterozygous missense mutations, p.Pro200Thr and p.Arg237Pro; and two further Turkish families with Crouzon-like syndrome carrying the homozygous nonsense mutations p.Tyr232* and p.Arg292*. Using transient coexpression in HEK293T and COS7 cells, we demonstrated dramatically reduced IL11-mediated STAT3 phosphorylation for all mutations. Immunofluorescence analysis of mouse Il11ra demonstrated specific protein expression in cranial mesenchyme which was localized around the coronal suture tips and in the lambdoidal suture. In situ hybridization analysis of adult zebrafish also detected zfil11ra expression in the coronal suture between the overlapping frontal and parietal plates. This study demonstrates that mutations in the IL11RA gene cause an autosomal recessive Crouzon-like craniosynostosis.

Adult zebrafish as a model system for cutaneous wound-healing research

Upon injury, the skin must quickly regenerate to regain its barrier function. In mammals, wound healing is rapid and scar-free during embryogenesis, whereas in adults it involves multiple steps including blood clotting, inflammation, re-epithelialization, vascularization, and granulation tissue formation and maturation, resulting in a scar. We have established a rapid and robust method to introduce full-thickness wounds onto the flank of adult zebrafish, and show that apart from external fibrin clot formation, all steps of adult mammalian wound repair also exist in zebrafish. Wound re-epithelialization is extremely rapid and initiates with no apparent lag-phase, subsequently followed by the immigration of inflammatory cells and the formation of granulation tissue, consisting of macrophages, fibroblasts, blood vessels and collagen. The granulation tissue later regresses, resulting in minimal scar formation. Studies after chemical treatment or with transgenic fish further suggest that wound re-epithelialization occurs independently of inflammation and Fibroblast growth factor (FGF) signaling, whereas both are essential for fibroblast recruitment and granulation tissue formation. Together these results demonstrate that major steps and principles of cutaneous wound healing are conserved among adult mammals and adult zebrafish, making zebrafish a valuable model for studying vertebrate skin repair.

Basement membrane diseases in zebrafish

Basement membranes (BMs) are a complex, sheet-like network of specialized extracellular matrix that underlies epithelial cells and surrounds muscle cells. They provide adherence between neighboring tissues, permit some flexibility of these adherent structures, and can act as a store for growth factors and as a guide for cell migration. The BM is not just a static structure; its deposition and remodeling are important for many processes including embryonic development, immune response, and wound healing. To date, dysfunction in BM deposition or remodeling has been linked to many human congenital disorders and diseases, affecting many different tissues in the body, including malformations, dystrophies, and cancer. However, many questions remain to be answered on the role BM proteins, and their mutations, play in the pathogenesis of human disease. In recent years, the zebrafish (Danio rerio) has emerged as a powerful animal model for human development and disease. In the first part of this chapter, we provide an overview of described defects caused by BM dysfunction in zebrafish, including development and function of notochord, muscle, central nervous system, skin, cardiovascular system, and kidney. In the second part, we will describe details of methods used to visualize and assess the structure of the BM in zebrafish, and to functionally analyze its different components.

Probability of early pregnancy loss in women with vaginal bleeding and a singleton live fetus at ultrasound scan

Bleeding is a common feature of early pregnancy affecting about one-fifth of pregnant women in the first trimester. The chance of miscarriage after bleeding and a live fetus at scan has not previously been defined precisely. The purpose of this study was to evaluate the outcome of early pregnancies with a viable singleton fetus that had been complicated by bleeding. A prospective study was performed on 370 women with a singleton live fetus who had presented to the early pregnancy assessment clinic (EPAC) with vaginal bleeding. Women were grouped into light, moderate and heavy loss according to the self-assessed degree of vaginal bleeding. The women were also categorised according to the presence or absence of an intrauterine haematoma. The overall spontaneous miscarriage rate in the study was 11.1%; almost 90% of pregnancies continued to viability. Women with moderate or heavy bleeding had more than twice the rate of miscarriage compared with those with light bleeding. A total of 14% of the women had an intrauterine haematoma and those women were 2.6 times more likely to miscarry than those without (23% vs 9%). This relationship appeared to hold true even after controlling for blood loss. The data presented can be used to guide women with a live fetus about the chance of miscarriage after an episode of vaginal bleeding. We propose that a large multi-centre study should be undertaken to define precisely the risk miscarriage for each gestational week according to a range of clinical and ultrasound characteristics.

Improving emergency attendance and mortality--the case for unit separation

BACKGROUND

Emergency attendance and mortality which are reliable indicators of quality of care, have been of concern to many health institutions. Different models are being proposed to improve emergency outcomes in different parts of the world. A model to separate a single emergency unit into multiple emergency units has been tried in Ghana.

OBJECTIVE

The objective of the study was to find the effect of the Unit Separation Model (USM) on the quality of emergency care delivery in a developing country.

METHODS

The study compared the outcomes (attendance and mortality) in a Single Emergency Model (SEM) with a USM, over a two-year period. Two groups of patients were studied--the SEM phase comprising 809 patients, and the USM phase comprising 3,505 patients. Data on patients' attendance and mortality in the two groups were analysed.

RESULTS

Attendance increased four fold in the USM period compared to the SEM period. This also reflected in increases in individual unit attendance. There was almost a three fold increase in medical and surgical emergencies, over ten fold increase in gynaecological emergencies and over twenty fold increase in paediatric emergencies. There was a statistically significant reduction in emergency mortality in the USM period compared to the SEM period. Reductions in mortality were from 27.8% to 7.9% for Surgery, 46.3% to 23.2% for Medicine, 17.5% to 0.8% for Gynaecology, and 50.0% to 8.4% for Paediatrics (p-value < 0.001 for each unit); and overall from 36.7% to 10.9%.

CONCLUSION

It is concluded that Unit Separation Model with Specialty based emergency care has a positive impact of increasing emergency admissions and reducing mortality, without compromising quality. This also means that avoidable mortalities occur in the Single Emergency Model system.

Immunohistochemical localization of Toll-like receptors 1-10 in periodontitis

BACKGROUND/AIM

In periodontitis, bacteria and pathogen-associated molecular patterns are sensed by Toll-like receptors (TLRs), which initiate intracellular signaling cascades that may lead to host inflammation. In this study, the expression and distribution of TLRs (TLR-1 to TLR-10) were immunohistochemically detected in gingival epithelium and connective tissue.

METHODS

Immunohistochemistry was used for the localization of TLRs in gingival tissue samples from 10 patients with chronic periodontitis and 10 healthy controls; these samples were obtained during routine periodontal flap operations and during extraction operations performed for retained wisdom teeth, respectively. For the evaluation, epithelial layers were stratified to basal, spinous, and superficial layers, and the percentages of TLR-positive cells were determined.

RESULTS

Both healthy and periodontitis gingival tissues expressed all TLRs except TLR-10. In patients with periodontitis, epithelial cells showed increased TLR expression towards the basal layer. Healthy controls showed more variable cellular TLR expression and distribution between the layers of epithelium. In the connective tissue, consistently higher TLR expression was found within the periodontitis group compared to the healthy group.

CONCLUSIONS

For the first time, the cellular expression and distribution of TLR-1 to TLR-10 have been studied in periodontitis, indicating that TLR-1 to TLR-9 are differentially expressed both in connective tissue and epithelial layers. Except for TLR-7 and TLR-8, all the other TLRs showed statistically significant differences between patients with periodontitis and healthy controls, suggesting their involvement in the pathogenesis of periodontitis.

Taking the next step in 2005, the year of the diabetic foot

OBJECTIVES

To determine the age-standardized rate of lower limb amputations among Type 2 diabetics admitted to the Port of Spain General Hospital (POSGH), San Fernando General Hospital (SFGH) and Sangre Grande County Hospital (SGCH) for the period 2000-2004. To determine in-hospital mortality following amputation, for the same period. To determine the risk factors that contributed to diabetic foot complications.

DESIGN AND METHODS

All patients who had a lower limb amputation at the three major public health institutions in Trinidad during the study period were enrolled. In addition patients attending the surgical out-patient clinic and currently admitted to the ward with a diabetic septic foot was selected for the administration of a questionnaire to determine the major contributing factors. Data on the type of amputation, age, sex, ethnicity, from which an age-standardized mortality rate, was determined for the age group 30-60.

RESULTS

Of 822 patient files examined, 515 (80%) of these major amputations were performed on Type 2 diabetics, of which 352 (68%) were AKA and 163 (32%) were BKA. The AKA:BKA ratio for the period 2000-2004 was 2.2:1. There was a significant difference between the mean ages at which females had a major amputation to males (p=0.001). The overall ratio of Africans to South East Asians was 1.5:1 amongst the Type 2 diabetic amputees. For major amputations the average length of stay was found to be 22.5 (0-192) days. The age-standardized rate for the age group 30-60 was 13.85 per 100,000 for 2004. Of 66 deaths, 31 (47%) were septicemia cases and 14 (21%) cardio-respiratory failure cases. Finally, of 97 persons interviewed, the major causative agent for diabetic foot complications and amputations was foot trauma (51%).

CONCLUSION

Type 2 diabetic amputation status of Trinidad would seem to have improved as shown by this study. However, steps must be taken to improve patient awareness about prevention and care of the diabetic foot. Doctors must also seek to increase their vigilance when screening diabetic patient in the primary care setting in order to prevent the late detection and treatment of the septic lower limb.