Dioscin Activates Endoplasmic Reticulum Unfolded Protein Response for Defense Against Pathogenic Bacteria in Caenorhabditis elegans via IRE-1/XBP-1 Pathway.

The unfolded protein response (UPR) is an evolutionarily conserved pathway that senses and responds to the accumulation of misfolded proteins in the endoplasmic reticulum (ER) lumen during bacterial infection. The IRE-1/XBP-1 pathway is a major branch of the UPRER that has been conserved from yeast to human. Dioscin, a steroidal saponin exhibits a broad spectrum of properties. However, whether dioscin influences the immune response and the underlying molecular mechanisms remain obscure. We find that dioscin increases resistance to Gram-negative pathogen Pseudomonas aeruginosa. Furthermore, dioscin also inhibits the growth of pathogenic bacteria. Meanwhile, dioscin enhances the resistance to pathogens by reducing bacterial burden in the intestine. Through genetic screening, we find that dioscin activates the UPRER to promote innate immunity via IRE-1/XBP-1 pathway. Intriguingly, dioscin requires the neural XBP-1 for immune response. Our findings suggest that dioscin may be a viable candidate for the treatment of infectious diseases.

GWAS identifies two important genes involved in Chinese chestnut weight and leaf length regulation.

There are many factors that affect the yield of Chinese chestnut (Castanea mollissima), with single nut weight (SNW) being one of the most important. Leaf length is also related to Chinese chestnut yield. However, the genetic architecture and gene function associated with Chinese chestnut nut yield have not been fully explored. In this study, we performed genotyping by sequencing 151 Chinese chestnut cultivars, followed by a genome-wide association study (GWAS) on six horticultural traits. First, we analyzed the phylogeny of the Chinese chestnut and found that the Chinese chestnut cultivars divided into two ecotypes, a northern and southern cultivar group. Differences between the cultivated populations were found in the pathways of plant growth and adaptation to the environment. In the selected regions, we also found interesting tandemly arrayed genes that may influence Chinese chestnut traits and environmental adaptability. To further investigate which horticultural traits were selected, we performed a GWAS using six horticultural traits from 151 cultivars. Forty-five loci that strongly associated with horticultural traits were identified, and six genes highly associated with these traits were screened. In addition, a candidate gene associated with SNW, APETALA2 (CmAP2), and another candidate gene associated with leaf length (LL), CRYPTOCHROME INTERACTING BASIC HELIX-LOOP-HELIX 1 (CmCIB1), were verified in Chinese chestnut and Arabidopsis (Arabidopsis thaliana). Our results showed that CmAP2 affected SNW by negatively regulating cell size. CmCIB1 regulated the elongation of new shoots and leaves by inducing cell elongation, potentially affecting photosynthesis. This study provided valuable information and insights for Chinese chestnut breeding research.

Indole produced during dysbiosis mediates host-microorganism chemical communication.

An imbalance of the gut microbiota, termed dysbiosis, has a substantial impact on host physiology. However, the mechanism by which host deals with gut dysbiosis to maintain fitness remains largely unknown. In Caenorhabditis elegans, Escherichia coli, which is its bacterial diet, proliferates in its intestinal lumen during aging. Here, we demonstrate that progressive intestinal proliferation of E. coli activates the transcription factor DAF-16, which is required for maintenance of longevity and organismal fitness in worms with age. DAF-16 up-regulates two lysozymes lys-7 and lys-8, thus limiting the bacterial accumulation in the gut of worms during aging. During dysbiosis, the levels of indole produced by E. coli are increased in worms. Indole is involved in the activation of DAF-16 by TRPA-1 in neurons of worms. Our finding demonstrates that indole functions as a microbial signal of gut dysbiosis to promote fitness of the host.

Ceramide d18:1/24:1 as a potential biomarker to differentiate obesity subtypes with unfavorable health outcomes.

BACKGROUND: The criteria for metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) remain controversial. This research aimed to identify a potential biomarker to differentiate the subtypes of obesity. METHODS: The study conducted a lipidomic evaluation of ceramide in the serum of 77 Chinese adults who had undergone hyperinsulinemic-euglycemic clamps. These adults were divided into three groups according to the clinical data: normal weight control group (N = 21), MHO (N = 20), and MUO (N = 36). RESULTS: The serum Cer d18:1/24:1 level in the MHO group was lower than that in the MUO group. As the Cer d18:1/24:1 level increased, insulin sensitivity decreased, and the unfavorable parameters increased in parallel. Multivariate logistic regression analysis revealed that serum Cer d18:1/24:1 levels were independently correlated with MUO in obesity. Individuals with higher levels of Cer d18:1/24:1 also had an elevated risk of cardiovascular disease. Most ceramide subtype levels increased in obesity compared to normal-weight individuals, but the levels of serum Cer d18:0/18:0 and Cer d18:1/16:0 decreased in obesity. CONCLUSIONS: The relationships between ceramide subtypes and metabolic profiles might be heterogeneous in populations with different body weights. Cer d18:1/24:1 could be a biomarker that can be used to differentiate MUO from MHO, and to better predict who will develop unfavorable health outcomes among obese individuals. TRIAL REGISTRATION: The First Affiliated Hospital of Nanjing Medical University's Institutional Review Board authorized this study protocol, and all participants provided written informed consent (2014-SR-003) prior to study entry.

Genetic analysis and functional study of a novel ABCG5 mutation in sitosterolemia with hematologic disease.

Sitosterolemia is a rare autosomal recessive hereditary disease caused by loss-of-function genetic mutations in either ATP-binding cassette subfamily G member 5 or member 8 (ABCG5 or ABCG8). Here, we investigate novel variants in ABCG5 and ABCG8 that are associated with the sitosterolemia phenotype. We describe a 32-year-old woman with hypercholesterolemia, tendon and hip xanthomas, autoimmune hemolytic anemia and macrothrombocytopenia from early life, which make us highly suspicious of the possibility of sitosterolemia. A novel homozygous variant in ABCG5 (c.1769C>A, p.S590X) was identified by genomic sequencing. We also examined the lipid profile, especially plant sterols levels, using gas chromatography-mass spectrometry. Functional studies, including western blotting and immunofluorescence staining, showed that the nonsense mutation ABCG5 1769C>A hinders the formation of ABCG5 and ABCG8 heterodimers and the function of transporting sterols. Our study expands the knowledge of variants in sitosterolemia and provides diagnosis and treatment recommendations.

Functional Characterization of MC4R Variants in Chinese Morbid Obese Patients and Weight Loss after Bariatric Surgery.

Mutations in MC4R are the most common genetic cause of obesity. In the reported Chinese morbid obesity cohort, 10 out of 59 harbor six MC4R variants, including Y35C, T53I, V103I, R165W, G233S, and C277X, among which V103I has a relatively high frequency, while other five variants are rare in the population. The prevalence of MC4R carriers in Chinese morbid obese patients (body mass index ≥ 45 kg m-2 ) is detected as 16.9% in this study. R165W and C277X are loss-of-function variants. The patient with R165W achieves excess weight loss (%EWL) as high as 20.6% and 50.3% at 1 and 8 months after surgery, respectively. G233S is reported for the first time in Asia obese population. The patient harboring G233S has a %EWL as 23.3% one month postsurgery. It is concluded that morbid obese patients with rare MC4R variants can benefit from metabolic surgery. More importantly, the choice of surgery procedure and MC4R variant should be taken into consideration for personalized treatment. In the future, a larger size cohort, accompanied with regular and longer follow-up, would be helpful.

Effects of contact tracing and nucleic acid testing on the COVID-19 outbreak in Zunyi, China: data-driven study using a branching process model.

BACKGROUND: During October 2021, China experienced localized outbreaks of COVID-19 in many cities. We analyzed the small local outbreak in Zunyi (Guizhou Province), a major city in southwestern China, and modeled the effects of different interventions on this outbreak. METHODS: Data on infections and contacts, provided by the Health Commission of Guizhou Province, were used to analyze the epidemiological characteristics of the outbreak and calculate the effectiveness of vaccination. A branching process model was used to simulate the outbreak. This model considered the time interval from exposure of the initial case to confirmation, the number of potential infections caused by the initial case, and the effects of the different interventions. RESULTS: From 18 to 25 October 2021, there were 12 patients with COVID-19 in Zunyi. Overall, the average age was 67.17 years-old, 8 patients were females, and 1 patient had an asymptomatic infection. The effectiveness of two-dose inactivated vaccine against SARS-CoV-2 infection was 16.7% (95% CI: 2.8% to 99.7%). The initial case was infected on 11 or 12 October 2021, 6.40 (95% CI: 6.37, 6.42; IQR: 4.92, 7.63) days before confirmation while the travelling in Lanzhou (Gansu Province). There were 10.07 (95% CI: 10.04, 10.09; IQR: 7.86, 11.93) potential secondary cases. When the effective vaccine coverage reached 60%, the probability of cumulative cases exceeding 20 was less than 8.77%, even if contact tracing was relaxed or eliminated. However, if the probability of tracing contacts decreased, earlier initiation of nucleic acid testing was necessary to control the outbreak. CONCLUSIONS: The COVID-19 outbreak in Zunyi was controlled quickly due to moderately effective vaccine coverage and rapid contact tracing. For controlling localized outbreaks, vaccination and contact tracing seemed to be more effective than massive nucleic acid testing in the initial phase of transmission. However, if there is low effective vaccine coverage or insufficient contact tracing, nucleic acid testing should start earlier.

The EGL-30 pathway regulates experience-dependent aversive behavior of Caenorhabditis elegans to the pathogenic bacterium Pseudomonas aeruginosa.

Avoidance of harmful substances is survival strategy used cross invertebrates and vertebrates. For example, the nematode Caenorhabditis elegans evolves a sufficient avoidance response to pathogenic bacteria. Despite G protein has been found to exert neural plasticity for avoidance behaviours in C. elegans, the function of Gi/o and Gq subunit signalling in experience-dependent aversive behaviour remains unclear. In this study, we show that EGL-30/Gq coupled with EGL-8/UNC-13 regulates aversive behaviour of C. elegans to pathogenic bacterium Pseudomonas aeruginosa PA01 via acetylcholine and its receptor nAChR. Pyocyanin, a toxin secreted from P. aeruginosa, acts as a signal molecule to trigger aversive behaviour. ODR-3 and ODR-7 in AWA and AWC neurons function as upstream of EGL-30 to induce experience-dependent aversive behaviour to P. aeruginosa, respectively. These results suggested that a novel signalling pathway to regulate a behavioural response.

Brevilin A enhances innate immunity and the resistance of oxidative stress in Caenorhabditis elegans via p38 MAPK pathway.

The conserved p38/PMK-1 pathway that is an evolutionarily conserved module used by mammals and nematodes in immune response against bacterial infections. Brevilin A (BA), a sesquiterpene lactone compound of Centipeda minima has been shown to exhibit activities such as anti-tumor, anti-bacterial and anti-protozoal. However, whether the Brevilin A influences the immune response and the underlying molecular mechanisms remain obscure. We find that 10 µM Brevilin A increases resistance to not only the Gram-negative pathogens Pseudomonas aeruginosa and Salmonella enterica but also the Gram-positive pathogens Enterococcusfaecalis and Staphylococcus aureus. Meanwhile, Brevilin A enhances the resistance to pathogens by reducing the bacterial burden in the intestine. Through the genetic screening in C. elegans, we find that Brevilin A promotes innate immunity via p38 MAPK pathway. Furthermore, Brevilin A activates the p38/PMK-1 in the intestine for innate immune response. In addition, we also find that Brevilin A increases the resistance of oxidative stress and extends lifespan through p38 MAPK pathway. Our work suggests that Brevilin A may be a viable candidate for the treatment of infectious diseases.

The p38 MAPK/PMK-1 Pathway Is Required for Resistance to Nocardia farcinica Infection in Caenorhabditis elegance.

Nocardia farcinica is an opportunistic pathogen that causes nocardiosis primarily in patients with compromised immune systems. In this study, we used the genetically tractable organism Caenorhabditis elegans as a model to study the innate immune responses to N. farcinica infection. We found that unlike other pathogenic bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus, N. farcinica failed to kill adult worms. In another words, adult worms exposed to N. farcinica exhibited a normal lifespan, compared with those fed the standard laboratory food bacterium Escherichia coli OP50. Interestingly, deletion of three core genes (pmk-1, nsy-1 and sek-1) in the p38 MAPK/PMK-1 pathway reduced the survival of worm exposure to N. farcinica, highlighting a crucial role of this pathway for C. elegans in resistance to N. farcinica. Furthermore, our results revealed that N. farcinica exposure up-regulated the level of PMK-1 phosphorylation. The activation of PMK-1 promoted nuclear translocation of a transcription factor SKN-1/Nrf2, which in turn mediated N. farcinica infection resistance in C. elegans. Our results provide an excellent example that the integrity of immune system is key aspect for counteract with pathogenesis of N. farcinica.

Rare Diseases in Glycosphingolipid Metabolism.

Sphingolipidoses is a cluster of genetic rare disorders regarding glycosphingolipid metabolism, classified as lysosomal storage disorders (LSD). Here, we focus on eight inheritable diseases, including GM1 gangliosidosis, GM2 gangliosidosis, Fabry disease, Gaucher's disease, metachromatic leukodystrophy, Krabbe disease, Niemann-Pick disease A and B, and Farber disease. Mostly, pathogenic mutations in the key enzyme are loss-function, resulting in accumulation of substrates and deficiency of products. Thus, cellular overload of substrates causes lipotoxicity, which is deleterious to cellular and organ function. In the terms of clinical manifestations in sphingolipidoses, multiple systems and organs, especially central nervous system (CNS) are usually affected. As for diagnosis strategy, enzymatic activity assay and genetic sequencing are helpful. Up till now, limited treatment approaches have approved for treating sphingolipidoses, with some potential strategies for further evaluation. In general, enzyme replacement therapy (ERT), substrate reduction therapy (SRT), and molecular chaperones are feasible choices for enzyme deficiency disorders, but these therapies are limited to relieve CNS lesions and symptoms due to prevention from blood-brain barrier. Other possible treatments such as gene therapy, bone marrow transplantation (BMT), and hematopoietic stem cell transplantation (HSCT) need further evaluation.

Impaired Insulin Clearance as the Initial Regulator of Obesity-Associated Hyperinsulinemia: Novel Insight Into the Underlying Mechanism Based on Serum Bile Acid Profiles.

OBJECTIVE: To investigate the roles of insulin clearance and insulin secretion in the development of hyperinsulinemia in obese subjects and to reveal the association between insulin clearance and bile acids (BAs). RESEARCH DESIGN AND METHODS: In cohort 1, insulin secretion, sensitivity, and endogenous insulin clearance were evaluated with an oral glucose tolerance test in 460 recruited participants. In cohort 2, 81 participants underwent an intravenous glucose tolerance test and a hyperinsulinemic-euglycemic clamp to assess insulin secretion, endogenous and exogenous insulin clearance, and insulin sensitivity. Based on insulin resistance levels ranging from mild to severe, obese participants without diabetes were further divided into 10 quantiles in cohort 1 and into tertiles in cohort 2. Forty serum BAs were measured in cohort 2 to examine the association between BAs and insulin clearance. RESULTS: All obese participants had impaired insulin clearance, and it worsened with additional insulin resistance in obese subjects without diabetes. However, insulin secretion was unchanged from quantile 1 to 3 in cohort 1, and no difference was found in cohort 2. After adjustments for all confounding factors, serum-conjugated BAs, especially glycodeoxycholic acid (GDCA; ß = -0.335, P = 0.004) and taurodeoxycholic acid (TDCA; ß = -0.333, P = 0.003), were negatively correlated with insulin clearance. The ratio of unconjugated to conjugated BAs (ß = 0.335, P = 0.002) was positively correlated with insulin clearance. CONCLUSIONS: Hyperinsulinemia in obese subjects might be primarily induced by decreased insulin clearance rather than increased insulin secretion. Changes in circulating conjugated BAs, especially GDCA and TDCA, might play an important role in regulating insulin clearance.

Rare Diseases Related with Lipoprotein Metabolism.

Rare diseases are gathering increasing attention in last few years, not only for its effects on innovation scientific research, but also for its propounding influence on common diseases. One of the most famous milestones made by Michael Brown and Joseph Goldstein in metabolism field is the discovery of the defective gene in familial hypercholesterolemia, a rare human genetic disease manifested with extreme high level of serum cholesterol (Goldstein JL, Brown MS, Proc Natl Acad Sci USA 70:2804-2808, 1973; Brown MS, Dana SE, Goldstein JL, J Biol Chem 249:789-796, 1974). Follow-up work including decoding the gene function, mapping-related pathways, and screening therapeutic targets are all based on the primary finding (Goldstein JL, Brown MS Arterioscler Thromb Vasc Biol 29:431-438, 2009). A series of succession win the two brilliant scientists the 1985 Nobel Prize, and bring about statins widely used for lipid management and decreasing cardiovascular disease risks. Translating the clinical extreme phenotypes into laboratory bench work has turned out to be the first important step in the paradigm conducting translational and precise medical research. Here we review the main categories of rare disorders related with lipoprotein metabolism, aiming to strengthen the notion that human rare inheritable genetic diseases would be the window to know ourselves better, to treat someone more efficiently, and to lead a healthy life longer. Few rare diseases related with lipoprotein metabolism were clustered into six sections based on changes in lipid profile, namely, hyper- or hypocholesterolemia, hypo- or hyperalphalipoproteinemia, abetalipoproteinemia, hypobetalipoproteinemia, and sphingolipid metabolism diseases. Each section consists of a brief introduction, followed by a summary of well-known disease-causing genes in one table, and supplemented with one or two diseases as example for detailed description. Here we aimed to raise more attention on rare lipoprotein metabolism diseases, calling for more work from basic research and clinical trials.

Antioxidant response is a protective mechanism against nutrient deprivation in C. elegans.

Animals often experience periods of nutrient deprivation; however, the molecular mechanisms by which animals survive starvation remain largely unknown. In the nematode Caenorhabditis elegans, the nuclear receptor DAF-12 acts as a dietary and environmental sensor to orchestrate diverse aspects of development, metabolism, and reproduction. Recently, we have reported that DAF-12 together with co-repressor DIN-1S is required for starvation tolerance by promoting fat mobilization. In this report, we found that genetic inactivation of the DAF-12 signaling promoted the production of reactive oxygen species (ROS) during starvation. ROS mediated systemic necrosis, thereby inducing organismal death. The DAF-12/DIN-1S complex up-regulated the expression of antioxidant genes during starvation. The antioxidant enzyme GST-4 in turn suppressed ROS formation, thereby conferring worm survival. Our findings highlight the importance of antioxidant response in starvation tolerance and provide a novel insight into multiple organisms survive and adapt to periods of nutrient deprivation.

GPH1 is involved in glycerol accumulation in the three-dimensional networks of the nematode-trapping fungus Arthrobotrys oligospora.

Turgor is very important for the invasive growth of fungal pathogens. Glycerol, a highly osmotic solvent, is considered to play an important role in turgor generation. The nematophagous fungus Arthrobotrys oligospora mainly lives as a saprophyte. In the presence of nematodes, A. oligospora enters the parasitic stage by forming three-dimensional networks (traps) to capture nematodes. In A. oligospora, we found that glycerol accumulated during nematode-induced trap formation. We demonstrated that deleting gph1, which encodes glycogen phosphorylase, decreased the glycerol content, compared with that of a wild-type strain. Although the number of traps induced by nematodes was not affected in the Δgph1 mutant, the capture rate was lower. Meanwhile, deleting gph1 also affected the growth rate and conidiation capacity of the fungus. These results indicate that glycerol derived from GPH1 is essential for the full virulence of A. oligospora against nematodes.

Systematic analyses reveal uniqueness and origin of the CFEM domain in fungi.

CFEM domain commonly occurs in fungal extracellular membrane proteins. To provide insights for understanding putative functions of CFEM, we investigate the evolutionary dynamics of CFEM domains by systematic comparative genomic analyses among diverse animals, plants, and more than 100 fungal species, which are representative across the entire group of fungi. We here show that CFEM domain is unique to fungi. Experiments using tissue culture demonstrate that the CFEM-containing ESTs in some plants originate from endophytic fungi. We also find that CFEM domain does not occur in all fungi. Its single origin dates to the most recent common ancestors of Ascomycota and Basidiomycota, instead of multiple origins. Although the length and architecture of CFEM domains are relatively conserved, the domain-number varies significantly among different fungal species. In general, pathogenic fungi have a larger number of domains compared to other species. Domain-expansion across fungal genomes appears to be driven by domain duplication and gene duplication via recombination. These findings generate a clear evolutionary trajectory of CFEM domains and provide novel insights into the functional exchange of CFEM-containing proteins from cell-surface components to mediators in host-pathogen interactions.

Recombinant human lactoferrin enhances the efficacy of triple therapy in mice infected with Helicobacter pylori.

Helicobacter pylori (H. pylori) is a life-threatening pathogen which causes chronic gastritis, gastric ulcers and even stomach cancer. Treatment normally involves bacterial eradication; however, this type of treatment only has a rate of effectiveness of <80%. Thus, it is a matter of some urgency to develop new therapeutic strategies. Lactoferrin, a member of the transferrin family of iron-binding proteins, has been proven to be effective in removing a vast range of pathogens, including H. pylori. In the present study, we examined the effectiveness of recombinant human lactoferrin (rhLf) isolated from transgenic goats as a treatment for H. pylori in vitro and in vivo. For the in vivo experiments, BALB/c mice received an intragastric administration of 0.1 ml of a suspension of H. pylori. The mice were then divided into 4 groups: group A, treated with saline; group B, treated with 1.5 g of rhLF; group C, treated with the standard triple therapy regimen; and group D, treated with the standard triple therapy regimen plus.5 g of rhLF. Following sacrifice, the stomach tissues of the mice were histologically examined for the presence of bacteria. For the in vitro experiments, the bacteria were cultured in BHI broth and RT-qPCR and western blot analysis were carried out to determine the mRNA and protein levels of virulence factors (CagA and VacA) in the cultures. Our results revealed that rhLf not only inhibited the growth of H. pylori, but also suppressed the expression of two major virulence factors. Moreover, rhLf markedly increased bacterial eradication and effectively reduced the inflammatory response when combined with the standard triple therapy regimen. These results provide evidence supporting the use of rhLF as an adjuvant to traditional therapeutic strategies in the treatment of H. pylori.

Inhibition Effects of Some Bioactive Peroxovanadium Complexes on the Tyrosine Phosphatase.

In order to study the structure-activity relationship and molecular mechanism of insulin-mimetic peroxovanadium complexes, the low-molecular-weight BHPTPase from bovine heart has been purified mainly by chromatography of DEAE-cellulose and Sephadex G-75, which was showed homogenicity on SDS-PAGE. Four bioactive peroxovanadium(pV) complexes bpV(ox), bpV(bipy), bpV(phen) and bpV(pic), [VO(O(2))(2)L](n-), where L = oxalic acid dianion(ox), bipyridine(bipy), 1,10-phenanthroline(phen), pyridine-2-carboxylic acid(pic) have been synthesized the bonding properties of center metal and its ligand were characterized by (51)V NMR, (13)C NMR, IR and elemental analysis. The complexes displayed remarkable inhibitory effects on the bovine heart tyrosine phosphatase. Their IC(50) were 0.22, 0.36 and 0.90 and 0.28 &mgr;mol/L, respectively. The structure-activity relationship of the complexes were discussed by their oxidizing ability and through the steric space hindrance of the organic ligands.