Transcriptional analysis of natural killer T cell development

Type 1 NKT cells are an innate-like population of T cells that rapidly respond to both cytokine and TCR stimulation by the production of pro-inflammatory and immunoregulatory cytokines. Different from conventional αβT cells, which express a diverse repertoire of TCR sequences that are generated by random rearrangement and are positively selected by thymic epithelium expressing MHC Class I and Class II products, type 1 NKT cells express a highly restricted TCR (Vα14-Jα18 in mice, and the homologous Vα24-Jα18 chain in humans, paired with a restricted range of β chains) and are positively selected by ligating β2 Microglobulin (β2M)/CD1d and SLAM family members expressed on CD4⁺CD8⁺ (double positive – DP) cortical thymocytes. In the periphery of mice, type 1 NKT cells express a 'memory' or 'activated' like surface phenotype (CD62L⁻CD69⁺CD44hi) and the great majority is either CD4⁺CD8⁻ (single positive; SP) or CD4⁻CD8⁻ (double negative; DN). Studies on NKT cell development indicated that they are originated from the same progenitor as conventional T cells, and branched off from the mainstream lineage at DP stage. NKT cells' development is thymus dependent, they develop in fetal thymic organ culture; neonatal thymectomy on the third day of life selectively depletes them. NKT cells are not found in the peripheral tissues of mice until 1-2 weeks after birth. Many efforts have been made to understand the molecular mechanisms that govern their commitment and homeostasis. However, the very low numbers of developing NKT cells, especially DP NKT cells at Stage 0, makes it difficult to analyse transcriptional programs controlling NKT cell development. To further dissect the events surrounding NKT cell lineage commitment and to examine transcriptional factors controlling early NKT cell ontogeny, a mouse model with increased numbers of immature type 1 NKT cells was generated on the SLAM-deficient, NOD background. These mice were found to have greatly increased numbers of CD24⁺NK1.1⁻ DP NKT cells with the characteristics of pre-selection and Stage 0 NKT cells. This provides an opportunity to compare the transcriptional profiles of these very immature CD24⁺NK1.1⁻ DP NKT cells with those of conventional T cells (CD24⁺NK1.1⁻ DP T cells), and those of more mature NKT cell subsets, including CD24⁺NK1.1⁻ CD4⁺ NKT cells and CD24⁺NK1.1⁻ DN NKT cells. Expression levels of a total of 35,556 transcripts of each biological samples of above four different cell populations were obtained by microarray analysis. Principal component analysis indicated that the four populations clearly separated, in order, across principal component 1 from CD24⁺NK1.1⁻ DP T cells, to CD24⁺NK1.1⁻ DP NKT cells, to CD24⁺NK1.1⁻ CD4⁺ NKT cells, and finally to CD24⁺NK1.1⁻ DN NKT cells. Comparison of gene expression between these populations has provided an overall transcriptional profile during TCR validation, positive selection and lineage commitment of NKT cells. These findings have further confirmed phenotypic changes during NKT cell development observed by previous studies and suggest that immature DP NKT cells are pre-selection progenitors of NKT cells. Our transcriptional regulatory network approach mapped TCR validation to the transition from DP T to DP NKT cells, while positive selection and lineage commitment were associated with the transition from DP NKT to CD4 NKT cells. This is the first time that the effects of positive and negative selection have been examined on their actual population – the immature DP NKT cells. We confirm by in vivo experimentation that both positive and negative selection occur at the latter transition, separating for the first time in any T cell population the events associated with TCR validation from those associated with positive selection. NOD.Vα14Tg mice provide a model to study the earliest identifiable stages of NKT cell commitment and differentiation, and to help dissect factors controlling the numbers and function of this important immunoregulatory population

Modulation of TCR signalling components occurs prior to positive selection and lineage commitment in iNKT cells

iNKT cells play a critical role in controlling the strength and character of adaptive and innate immune responses. Their unique functional characteristics are induced by a transcriptional program initiated by positive selection mediated by CD1d expressed by CD4+CD8+ (double positive, DP) thymocytes. Here, using a novel Vα14 TCR transgenic strain bearing greatly expanded numbers of CD24hiCD44loNKT cells, we examined transcriptional events in four immature thymic iNKT cell subsets. A transcriptional regulatory network approach identified transcriptional changes in proximal components of the TCR signalling cascade in DP NKT cells. Subsequently, positive and negative selection, and lineage commitment, occurred at the transition from DP NKT to CD4 NKT. Thus, this study introduces previously unrecognised steps in early NKT cell development, and separates the events associated with modulation of the T cell signalling cascade prior to changes associated with positive selection and lineage commitment. © 2021, The Author(s). **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Stuart Berzins” is provided in this record*

Efficacy and Toxicity of Folfoxiri for Patients with Metastatic Colorectal Cancer

BACKGROUND: In recent times, scientists have found new treatments for colorectal cancer patients. AIM: The study is to evaluate the efficacy and toxicity of triplet combination chemotherapy of 5-fluorouracil/leucovorin, oxaliplatin, and irinotecan (FOLFOXIRI) for patients with metastatic colorectal cancer in stage IV. METHODS: Uncontrolled clinical trial carried on 39 stage IV colorectal cancer patients. RESULTS: The overall response rate of the treatment was 79.4%. The average progression-free survival was 13.4 ± 9 months. The overall survival rate at 12th month and 24th month were 90% and 76%, respectively. The proportion of granulocytopenia was 48.9%, no grade 3 or 4. Side effect beyond hematology was most seen in hepatic toxicity with 52.5%, mainly at grade 1. Vomiting was 18.3%, all at grade 1. Other adverse event was very low at percentage. CONCLUSIONS: The triplet combination FOLFOXIRI chemotherapy improves the outcome of patients with metastatic colorectal cancer regarding rate of response, overall survival rate and progression-free survival, and the level of toxicity was acceptable

Modulation of TCR signalling components occurs prior to positive selection and lineage commitment in iNKT cells

iNKT cells play a critical role in controlling the strength and character of adaptive and innate immune responses. Their unique functional characteristics are induced by a transcriptional program initiated by positive selection mediated by CD1d expressed by CD4+CD8+ (double positive, DP) thymocytes. Here, using a novel Vα14 TCR transgenic strain bearing greatly expanded numbers of CD24hiCD44loNKT cells, we examined transcriptional events in four immature thymic iNKT cell subsets. A transcriptional regulatory network approach identified transcriptional changes in proximal components of the TCR signalling cascade in DP NKT cells. Subsequently, positive and negative selection, and lineage commitment, occurred at the transition from DP NKT to CD4 NKT. Thus, this study introduces previously unrecognised steps in early NKT cell development and separates, the events associated with modulation of the T cell signalling cascade prior to changes associated with positive selection and lineage commitment

MicroRNA-146a regulates ICOS–ICOSL signalling to limit accumulation of T follicular helper cells and germinal centres

Tight control of T follicular helper (Tfh) cells is required for optimal maturation of the germinal centre (GC) response. The molecular mechanisms controlling Tfh-cell differentiation remain incompletely understood. Here we show that microRNA-146a (miR-146a) is highly expressed in Tfh cells and peak miR-146a expression marks the decline of the Tfh response after immunization. Loss of miR-146a causes cell-intrinsic accumulation of Tfh and GC B cells. MiR-146a represses several Tfh-cell-expressed messenger RNAs, and of these, ICOS is the most strongly cell autonomously upregulated target in miR-146a-deficient T cells. In addition, miR-146a deficiency leads to increased ICOSL expression on GC B cells and antigen-presenting cells. Partial blockade of ICOS signalling, either by injections of low dose of ICOSL blocking antibody or by halving the gene dose of Icos in miR-146a-deficient T cells, prevents the Tfh and GC B-cell accumulation. Collectively, miR-146a emerges as a post-transcriptional brake to limit Tfh cells and GC responses.This work was funded by the National Health and Medical Research Council (NHMRC) program and project grants and Elizabeth Blackburn Fellowship to C.G.V., International Postgraduate Research Scholarship to A.P., NHMRC/MSRA Betty Cuthbert Fellowship to M.A.J., National Research Service Award F30HL110691 and UCLA/Caltech Medical Scientist Training Program to J.L.Z

Expanding workplace HIV/AIDS prevention activities for a highly mobile population: Construction workers in Ho Chi Minh City

In Ho Chi Minh City, the locus of the HIV epidemic in Vietnam, efforts have been under way for several years to implement prevention efforts for migrant worker populations. The main activity has been volunteer health communicators (HCs) visiting workplaces and conducting HIV education activities. These efforts have reached only a small number of the intended audience, and the impact is unclear. Local authorities want to scale up their efforts but need information on the most effective and least costly activities, and their potential for scale up. The Horizons Program, the Population Council/Vietnam, and partners compared two programs for highly mobile construction workers: the existing HC workplace program, where social work students deliver HIV-prevention education, and a new peer-education program. Concerns exist about the turnover of health communicators in the HC program and whether social work students, about half of whom are female, are the most effective HIV-prevention educators for a largely male construction worker population. The new program uses construction worker peer educators to promote HIV risk reduction. Findings noted in this report indicate that the peer-educator program reached a higher proportion of workers than the health-communicator program

ELECTRODEPOSITION OF HYDROXYAPATITE/FUNCTIONALIZED CARBON NANOTUBES (HAp/fCNTs) COATINGS ON THE SURFACE OF 316L STAINLESS STEEL

The coatings of hydroxyapatite/functionalized carbon nanotubes (HAp/fCNTs) were successfully synthesized on the surface of 316L stainless steel (316L SS) by electrodeposition. To improve the dispersion of CNTs into the electrolyte, CNTs were functionalized in the mixture of 67 % HNO3 and 98 % H2SO4 before electrodeposition coatings to form fCNTs. Different amounts of fCNTs were  incorporated into the apatite coatings by adding fCNTs into the  electrolyte solution. In this study, Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA) and mechanical techniques were used to analyze characteristic of fCNTs and the HAp/fCNTs coatings. The FTIR spectra of CNTs before and after acid treated process show that CNTs are functionalized by chemically method with carboxylic acid groups (–COOH) on their surface. The SEM images confirm that the functionalized process by the acid mixture does not change the morphology of CNTs. The nanocomposite coatings contain single phase of HAp and CNTs with the coating thickness of 6.9 µm and the amount of fCNTs in the coatings is 7.25 %. With 0.5 g/L of fCNTs in the electrolyte solution, the solubility of the coating decreases in comparision with pure HAp coatings

PRESENT DAY DEFORMATION IN THE EAST VIETNAM SEA AND SURROUNDING REGIONS

This paper presents velocities of present-day tectonic movement and strain rate in the East Vietnam Sea (South China Sea) and surroundings determined from GPS campaigns between 2007 and 2010. We determine absolute velocities of GPS stations in the ITRF05 frame. The result indicates that GPS stations in the North of East Vietnam Sea move eastwards with the slip rate of 30 - 39 mm/yr, southwards at the velocities of 8 - 11 mm/yr. Song Tu Tay offshore moves eastwards at the rate of ~24 mm/yr and southwards at ~9 mm/yr. GPS stations in the South of East Vietnam Sea move to the east at the rate of ~22 mm/yr and to the south at the velocities of 7 - 11 mm/yr. The effect of relative movement shows that the Western Margin Fault Zone activates as left lateral fault zone at the slip rate less than 4 mm/year.In Western plateau, the first result from 2012 - 2013 GPS measurement shows that the velocities to the east vary from 21.5 mm/yr to 24.7 mm/year. The velocities to the south vary from 10.5 mm/yr to 14.6 mm/year. GPS solutions determined from our campaigns are combined with data from various authors and international projects to determine the strain rate in the East Vietnam Sea. Principal strain rate changes from 15 nanostrain/yr to 9 nanostrain/yr in the East Vietnam Sea. Principal strain rate and maximum shear strain rate along the Red River Fault Zone are in order of 10 nanostrain/year. East Vietnam Sea is considered to belong to the Sunda block

SIMULATION AS A TEACHING METHOD FOR NURSING EDUCATION IN HEALTHCARE-ASSOCIATED INFECTION PREVENTION AND CONTROL IN ASIAN COUNTRIES: A QUALITATIVE STUDY

BACKGROUND: Applying simulation for nursing education, especially in healthcare-associated infection prevention and control (HAI-PC) in developing countries has limited evidence. The study was conducted to explore educators’ perceptions of simulation as a teaching method for nursing education in HAI-PC in two Vietnamese and two Cambodian universities. METHODS: An exploratory qualitative design was applied. A focus group of 37 educators from four universities was conducted for data collection. Inductive and deductive qualitative content analysis was applied in analysing the data. RESULTS: The core category was constructed to reflect educators’ perception of scenario-based simulation (SBS) as a teaching method for nursing education in HAI prevention and control. This main category included three subcategories: (i) enhancing nursing competence; (ii) preparing students for simulation; and [1] promoting simulation pedagogy competence. CONCLUSIONS: The findings identified the importance and benefits of applying simulation as a teaching method in nursing education. Additionally, it emphasized the necessity of enhancing knowledge associated with HAIs and providing additional training on simulation for educators to improve the quality of conducting simulations

EXPERIENCES OF THE NURSING STUDENT IN LEARNING HAI PREVENTION AND CONTROL IN ASIAN COUNTRIES THROUGH THE USE OF SCENARIO-BASED SIMULATION: AN EXPLORATIVE QUALITATIVE STUDY

BACKGROUND: Healthcare-associated infections (HAIs) have posed a major threat to both patients and to the safety healthcare personnel worldwide. According to the World Health Organization, 10% of hospitalized patients are affected by HAIs worldwide. OBJECTIVE: The objective of this study was to explore the experiences of nursing students in learning HAIs prevention and control by the application of the scenario-based simulation pedagogy now in use in two Vietnamese and two Cambodian universities. METHODS: A qualitative study was conducted among 160 nursing students from 2 Cambodian universities and 2 Vietnamese universities, and by using the purposive-sampling method. The data were collected through a focus group discussion and analyzed by the Graneheim and Lundman method (Graneheim & Lundman, 2004). RESULTS: Two themes and six categories were generated. 1) First theme: factors for enhancing student learning on the prevention and control of HAIs by use of scenario-based simulation; and 2) Second theme: factors hindering students learning on HAI prevention and control by use of scenario-based simulation. CONCLUSION: The findings showed that SBS is an effective learning method for nursing students that can be applied to enhance the quality of nursing education in the Asian countries as SBS not only improves the clinical skills, but also the soft skills of nursing students. However, the effective outcomes and impacts can only be achieved in the context with the appropriate learning materials and equipment, simulation facilities and the instructors with pedagogical skills