A carbon-nitrogen negative feedback loop underlies the repeated evolution of cnidarian-Symbiodiniaceae symbioses.

Symbiotic associations with Symbiodiniaceae have evolved independently across a diverse range of cnidarian taxa including reef-building corals, sea anemones, and jellyfish, yet the molecular mechanisms underlying their regulation and repeated evolution are still elusive. Here, we show that despite their independent evolution, cnidarian hosts use the same carbon-nitrogen negative feedback loop to control symbiont proliferation. Symbiont-derived photosynthates are used to assimilate nitrogenous waste via glutamine synthetase-glutamate synthase-mediated amino acid biosynthesis in a carbon-dependent manner, which regulates the availability of nitrogen to the symbionts. Using nutrient supplementation experiments, we show that the provision of additional carbohydrates significantly reduces symbiont density while ammonium promotes symbiont proliferation. High-resolution metabolic analysis confirmed that all hosts co-incorporated glucose-derived 13C and ammonium-derived 15N via glutamine synthetase-glutamate synthase-mediated amino acid biosynthesis. Our results reveal a general carbon-nitrogen negative feedback loop underlying these symbioses and provide a parsimonious explanation for their repeated evolution.

Integrative oncology in cancer care - implementation factors: mixed-methods systematic review.

BACKGROUND: Integrative oncology (IO) appears to be beneficial to patients with cancer, but its implementation remains a challenge. Guided by the Theoretical Domains Framework (TDF) and the Capability-Opportunity-Motivation-Behaviour (COM-B) model, this systematic review identified the barriers to and facilitators of IO implementation in conventional cancer care settings. METHODS: We searched eight electronic databases from their inception until February 2022 for qualitative, quantitative or mixed-methods empirical studies reporting the implementation outcomes for IO services. Critical appraisal approach was tailored according to study types. The identified implementation barriers and facilitators were mapped onto TDF domains and the COM-B model, and subsequently onto the behavioural change wheel (BCW) for formulating behavioural change interventions. RESULTS: We included 28 studies (11 qualitative, 6 quantitative, 9 mixed-methods and 2 Delphi studies) of satisfied methodological quality. The main implementation barriers were the lack of IO knowledge, the absence of funding and healthcare professionals' low level of IO receptiveness. The key implementation facilitators were the dissemination of evidence on IO clinical benefits, the equipping of professionals with IO service delivery skills and the provision of a supportive organisational climate. CONCLUSION: Multifaceted implementation strategies are needed to address the determinants influencing IO service delivery. Based on our BCW-based analysis of the included studies, the key behavioural change techniques are: (1) educating healthcare professionals about the value and application of traditional and complementary medicine; (2) ensuring access to actionable clinical evidence on IO effectiveness and safety and (3) designing guidelines on communicating traditional and complementary medicine interventions with patients and caregivers for biomedically trained doctors and nurses.

Loss of biased signaling at a G protein-coupled receptor in overexpressed systems.

G protein-coupled receptors (GPCRs) regulate cellular signaling pathways by coupling to two classes of transducers: heterotrimeric G proteins and ß-arrestins. [Sarcosine1Ile4Ile8]-angiotensin II (SII), an analog of the endogenous ligand angiotensin II (AngII) for the angiotensin II type 1 receptor (AT1R), fails to activate G protein in physiologically relevant models. Despite this, SII and several derivatives induce cellular signaling outcomes through ß-arrestin-2-dependent mechanisms. However, studies reliant on exogenous AT1R overexpression indicate that SII is a partial agonist for G protein signaling and lacks ß-arrestin-exclusive functional specificity. We investigated this apparent discrepancy by profiling changes in functional specificity at increasing expression levels of AT1R using a stably integrated tetracycline-titratable expression system stimulated with AngII, SII, and four other AngII analogs displaying different signaling biases. Unbiased and G protein-biased ligands activated dose-dependent calcium responses at all tested receptor concentrations. In contrast, ß-arrestin-biased ligands induced dose-dependent calcium signaling only at higher AT1R overexpression levels. Using inhibitors of G proteins, we demonstrated that both Gi and Gq/11 mediated overexpression-dependent calcium signaling by ß-arrestin-biased ligands. Regarding ß-arrestin-mediated cellular events, the ß-arrestin-biased ligand TRV026 induced receptor internalization at low physiological receptor levels insufficient for it to initiate calcium signaling. In contrast, unbiased AngII exhibited no relative preference between these outcomes under such low receptor conditions. However, with high receptor overexpression, TRV026 lost its functional selectivity. These results suggest receptor overexpression misleadingly distorts the bias of AT1R ligands and highlight the risks of using overexpressed systems to infer the signaling bias of GPCR ligands in physiologically relevant contexts.

Biolayer interferometry is insufficiently sensitive for direct measurement of IgM quantity and avidity in Atlantic salmon (Salmo salar) serum.

Quantification of specific antibodies underpins the assessment of adaptive immunity in response to vaccination or infection and is performed by enzyme-linked immunosorbent assay (ELISA). A biolayer interferometry (BLI) assay was recently developed that simultaneously quantifies IgM antibodies and their avidity in giant grouper (Epinephelus lanceolatus) sera and proved to be a robust, repeatable and more high-throughput alternative to ELISA [1]. Here we attempted to optimise a similar single-step BLI assay using an Octet HTX instrument to quantify IgM specific to the hapten 2,4-dinitrophenol (DNP) in serum from Atlantic salmon (Salmo salar) primed and boosted with DNP conjugated to keyhole limpet hemocyanin.

Prevalence, Patterns, and Clinical Severity of Long COVID among Chinese Medicine Telemedicine Service Users: Preliminary Results from a Cross-Sectional Study.

INTRODUCTION: The emergence and persistence of symptoms after acute COVID-19 is expected to become a major burden on healthcare systems. We assessed the features of the post-COVID-19 Syndrome (Long COVID) burden in a cohort of COVID-19 patients during the fifth major wave in Hong Kong. METHODS: A cross-sectional study of 135 patients with confirmed COVID-19 from Feb to Apr 2022 who utilized traditional Chinese medicine telemedicine services was conducted. The COVID-19 Yorkshire Rehabilitation Scale was administered using an online survey 12 weeks after the COVID-19 infection. Prevalence of symptom severity and functional impairments were assessed to identify burdens and patterns. The correlation between symptom severity, functional impairments, patient characteristics, and overall health was evaluated. RESULTS: The mean age was 46.8 years, with 46 (34.1%) males. Symptoms, functional impairments, and overall health worsened significantly when compared to the status prior to the infection. More than 50% reported the following sequelae 12 weeks after the acute infection: breathlessness, laryngeal or airway complications, fatigue, weakness, sleep, cognition, and anxiety. The presence of a single symptom or functional impairment significantly correlated with at least seven other problems positively, except for pain. Severity tended to be higher among vulnerable groups, including those who were chronic disease patients, older, less well educated, female, or had incomplete COVID-19 vaccinations. CONCLUSIONS: Long COVID is a significant healthcare burden among telemedicine users in Hong Kong, with complex needs for symptom and functional impairment management. Designing relevant health and rehabilitation services tailored to the needs of these patients is warranted.

Motivations and deterrents of blood donation among blood donors during the COVID-19 pandemic in Hong Kong.

BACKGROUND: The COVID-19 pandemic has resulted in a reduction in blood donations and limited blood supply in many countries. The theory of planned behaviour has been widely used in past studies to understand the factors influencing blood donation. However, this theory limits analyses to the individual level. Furthermore, most research on the determinants of blood donation during the COVID-19 pandemic is quantitative in nature, with relevant qualitative research being rare. OBJECTIVES: To investigate the motivators and demotivators for donating blood among current blood donors during COVID-19 pandemic. DESIGN: Forty in-depth, individual semistructured interviews were conducted with current blood donors from December 2020 to March 2021 in Hong Kong. Thematic content analysis was adopted in the data analysis. RESULTS: The majority of the participants (n = 37) were demotivated from donating blood during the COVID-19 pandemic. Factors at the perceptual, social and institutional levels interacted to cause this reluctance. Only three participants felt more motivated to donate blood. The data revealed that sociocultural forces and government pandemic prevention policies strongly affected the participants' motivations to donate blood during the pandemic. CONCLUSION: This study presents a macro understanding of blood donation behaviour by investigating the institutional, social and perceptual factors influencing current blood donors during the COVID-19 pandemic. This adds a more comprehensive understanding of blood donation where the theory of planned behaviour is widely used in past studies. PUBLIC CONTRIBUTION: The participants shared their experiences in the interviews. Their experiences provide hints for explaining the decreasing blood donation during the pandemic times.

Reply to Comment on Shen H, et al. "Co-signaling receptors regulate T-cell plasticity and immune tolerance". Frontiers in Bioscience-Landmark. 2019; 24: 96-132.

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A single-step, high throughput, and highly reproducible method for measuring IgM quantity and avidity directly from fish serum via biolayer interferometry (BLI).

Quantification of specific antibody responses is critical in determining activation of MHCII-dependent immune memory and is generally performed by enzyme-linked immunosorbent assay (ELISA). Antibody avidity for a particular antigen is also informative of the quality of the adaptive immune response following vaccination. Avidity can be determined by chaotropic elution ELISA, pre-absorption ELISA, or surface plasmon resonance (SPR), although multimeric antibodies such as IgM are problematic for SPR. ELISA-based assays are very time consuming, require secondary antibody reagents, and are poorly repeatable. Here we demonstrate that biolayer interferometry (BLI) using an Octet HTX instrument can robustly and reproducibly quantify and determine avidity of specific IgM for an antigen directly from fish serum in a single step. We collected sera from giant grouper (Epinephelus lanceolatus) that had been vaccinated with the hapten 2,4-dinitrophenol conjugated to keyhole limpet hemocyanin (DNP-KLH) and from control fish injected with phosphate buffered saline. The specific IgM in the serum and its avidity for DNP were quantified via ELISA and BLI. BLI was precise and highly repeatable for determination of the quantity and avidity of antibody in the serum compared to ELISA. The wet-lab preparation and machine running time for BLI was 3-5 times faster than ELISA to generate the same amount of data. The ELISA inter-plate variation significantly affected reproducibility while BLI was consistent and repeatable between samples and plates. Indeed, the consistency of BLI data indicated that technical triplicates were redundant. Biological replication alone was sufficient to elucidate the effect of treatments. However, BLI required a lower serum dilution than ELISA for similar sensitivity, and thus more serum was required to produce high resolution data. BLI is an extremely high-throughput assay, providing teleost serum IgM quantification and avidity data as a single-step, agile alternative to ELISA.

Serum IgM heavy chain sub-isotypes and light chain variants revealed in giant grouper (Epinephelus lanceolatus) via protein A affinity purification, mass spectrometry and genome sequencing.

Two IgM heavy (H) chain sub-isotypes (80 and 40 kDa) and two light (L) chain variants (25 and 30 kDa) were detected in the serum of giant grouper (Epinephelus lanceolatus), purified by ammonium sulphate precipitation followed by protein A affinity chromatography. This method yielded 5.6 mg/mL high purity IgM from grouper serum, with efficiency estimated at 39.5% recovery from crude serum. The H and L chains were identified by SDS-PAGE and mass spectrometry (MS). Nanopore long-read sequencing was used to generate a genomic contig (MW768935), containing Cµ, Cδ loci, VH regions, and a H chain Joining segment. cDNA sequencing of Cµ transcripts (MW768933 and MW768934) were used to polish the genomic contig and determine the exons and introns of the corresponding locus. MS peptide mapping revealed that the 80 kDa H chain consisted of CH1-4 domains while peptides from the 40 kDa H chain only mapped to CH1-2 domains. Our genomic contig showed the Cµ locus has a Cµ1-Cµ2-Cµ3-Cµ4 arrangement on the same strand as the other Ig loci identified in this genomic sequence. Our study corrects the NCBI annotations of the opposing Cµ loci (LOC117268697 and LOC117268550) in chromosome 16 (NC_047006). Further, we identified both κ and λ L chain isotypes in serum IgM. The molecular weight differences observed may result from different combinations of CL and VL genes. Putative IgM sub-isotypes have also been reported in Epinephelus itajara and Epinephelus coioides. The presence of IgM sub-isotypes may be a conserved trait among Epinephelus species.

Increasing Upstream Chromatin Long-Range Interactions May Favor Induction of Circular RNAs in LysoPC-Activated Human Aortic Endothelial Cells.

Circular RNAs (circRNAs) are non-coding RNAs that form covalently closed continuous loops, and act as gene regulators in physiological and disease conditions. To test our hypothesis that proatherogenic lipid lysophosphatidylcholine (LPC) induce a set of circRNAs in human aortic endothelial cell (HAEC) activation, we performed circRNA analysis by searching our RNA-Seq data from LPC-activated HAECs, and found: (1) LPC induces significant modulation of 77 newly characterized cirRNAs, among which 47 circRNAs (61%) are upregulated; (2) 34 (72%) out of 47 upregulated circRNAs are upregulated when the corresponding mRNAs are downregulated, suggesting that the majority of circRNAs are upregulated presumably via LPC-induced "abnormal splicing" when the canonical splicing for generation of corresponding mRNAs is suppressed; (3) Upregulation of 47 circRNAs is temporally associated with mRNAs-mediated LPC-upregulated cholesterol synthesis-SREBP2 pathway and LPC-downregulated TGF-ß pathway; (4) Increase in upstream chromatin long-range interaction sites to circRNA related genes is associated with preferred circRNA generation over canonical splicing for mRNAs, suggesting that shifting chromatin long-range interaction sites from downstream to upstream may promote induction of a list of circRNAs in lysoPC-activated HAECs; (5) Six significantly changed circRNAs may have sponge functions for miRNAs; and (6) 74% significantly changed circRNAs contain open reading frames, suggesting that putative short proteins may interfere with the protein interaction-based signaling. Our findings have demonstrated for the first time that a new set of LPC-induced circRNAs may contribute to homeostasis in LPC-induced HAEC activation. These novel insights may lead to identifications of new therapeutic targets for treating metabolic cardiovascular diseases, inflammations, and cancers.

Co-signaling receptors regulate T-cell plasticity and immune tolerance.

We took an experimental database mining analysis to determine the expression of 28 co-signaling receptors in 32 human tissues in physiological/pathological conditions. We made the following significant findings: 1) co-signaling receptors are differentially expressed in tissues; 2) heart, trachea, kidney, mammary gland and muscle express co-signaling receptors that mediate CD4+T cell functions such as priming, differentiation, effector, and memory; 3) urinary tumor, germ cell tumor, leukemia and chondrosarcoma express high levels of co-signaling receptors for T cell activation; 4) expression of inflammasome components are correlated with the expression of co-signaling receptors; 5) CD40, SLAM, CD80 are differentially expressed in leukocytes from patients with trauma, bacterial infections, polarized macrophages and in activated endothelial cells; 6) forward and reverse signaling of 50% co-inhibition receptors are upregulated in endothelial cells during inflammation; and 7) STAT1 deficiency in T cells upregulates MHC class II and co-stimulation receptors. Our results have provided novel insights into co-signaling receptors as physiological regulators and potentiate identification of new therapeutic targets for the treatment of sterile inflammatory disorders.