High-fat diet promotes liver tumorigenesis via palmitoylation and activation of AKT.

OBJECTIVE: Whether and how the PI3K-AKT pathway, a central node of metabolic homeostasis, is responsible for high-fat-induced non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) remain a mystery. Characterisation of AKT regulation in this setting will provide new strategies to combat HCC. DESIGN: Metabolite library screening disclosed that palmitic acid (PA) could activate AKT. In vivo and in vitro palmitoylation assay were employed to detect AKT palmitoylation. Diverse cell and mouse models, including generation of AKT1C77S and AKT1C224S knock-in cells, Zdhhc17 and Zdhhc24 knockout mice and Akt1C224S knock-in mice were employed. Human liver tissues from patients with NASH and HCC, hydrodynamic transfection mouse model, high-fat/high-cholesterol diet (HFHCD)-induced NASH/HCC mouse model and high-fat and methionine/choline-deficient diet (HFMCD)-induced NASH mouse model were also further explored for our mechanism studies. RESULTS: By screening a metabolite library, PA has been defined to activate AKT by promoting its palmitoyl modification, an essential step for growth factor-induced AKT activation. Biologically, a high-fat diet could promote AKT kinase activity, thereby promoting NASH and liver cancer. Mechanistically, palmitoyl binding anchors AKT to the cell membrane in a PIP3-independent manner, in part by preventing AKT from assembling into an inactive polymer. The palmitoyltransferases ZDHHC17/24 were characterised to palmitoylate AKT to exert oncogenic effects. Interestingly, the anti-obesity drug orlistat or specific penetrating peptides can effectively attenuate AKT palmitoylation and activation by restricting PA synthesis or repressing AKT modification, respectively, thereby antagonising liver tumorigenesis. CONCLUSIONS: Our findings elucidate a novel fine-tuned regulation of AKT by PA-ZDHHC17/24-mediated palmitoylation, and highlight tumour therapeutic strategies by taking PA-restricted diets, limiting PA synthesis, or directly targeting AKT palmitoylation.

AMPK phosphorylates and stabilises copper transporter 1 to synergise metformin and copper chelator for breast cancer therapy.

BACKGROUND: Predominant roles of copper and its transporter, copper transporter 1 (CTR1), in tumorigenesis have been explored recently; however, the upstream regulation of CTR1 and combinational intervention of copper chelators in malignancies remain largely unclear. METHODS: CRISPR/Cas9-based kinome screening was used to identify the CTR1 upstream kinases. Immunofluorescence assays were utilised to detect CTR1 localisation. In vitro kinase assays and mass spectrometry were performed to detect CTR1 phosphorylation. Ubiquitination assays were performed to validate CTR1 stability. Colony formation, EdU labelling, Annexin V-FITC/PI-based apoptosis assays were carried out to detect the drug effect on cell growth and apoptosis. Xenografted mouse models were employed to investigate drug effects in vivo. RESULTS: We identify that CTR1 undergoes AMPK-mediated phosphorylation, which enhances CTR1 stabilisation and membrane translocation by affecting Nedd4l interaction, resulting in increased oncogenic roles in breast cancer. Importantly, activation of AMPK with its agonist metformin markedly enhances CTR1 levels, and leads to the combinational usage of AMPK agonists and copper chelators for breast cancer treatment. CONCLUSIONS: Our findings not only reveal the crosstalk between energy response and copper uptake via AMPK-mediated CTR1 phosphorylation and stability but also highlight the strategy to combat breast cancer by a combination of AMPK agonists and copper chelators. SIGNIFICANCE: The connection between energy response and copper homoeostasis is linked by AMPK phosphorylating and stabilising CTR1, which provides a promising strategy to combat breast cancer by combining AMPK agonists and copper chelators.

Expression of osteopontin and integrin αvß 3 receptor in retina of diabetic guinea pigs with high myopia.

INTRODUCTION: To investigate the effect of high myopia on the expression of retinal osteopontin (OPN) and integrin αVß 3 receptor in guinea pigs and determined the relationship between high myopia and diabetic retinopathy. METHODS: Ninety 3-week-old male guinea pigs were randomly divided into four groups that included normal control group (NOR，n=18), high myopia group (HM，n=24), diabetes group (DR，n=24), and diabetes with high myopia group (DR+HM，n=24). HM was induced by form deprivation (FDHM) in the right eye. The DR group was injected with 5% streptozotocin(STZ) 280 mg/kg intraperitoneally in the lower left abdomen of guinea pigs. The DRHM group was subjected to the same treatment as the HM and DR groups. Eighteen guinea pigs in each group were randomly selected to complete the experimental measurement. After enucleation of eyeballs, HE and immunohistochemical staining were performed to observe the retina morphology and count the positive rate of OPN and integrin αvß 3 receptor. RESULTS: Diabetic retinal changes were found in group DR and HM+DR. The degree of retinal change in group HM+DR was less than that in group DR. In the DR group, the morphology of retinal tissue was loose, the number of cells decreased, increased retinal microaneurysms, and a small amount of small artery embolism and venous thrombosis were observed. Although the retinal structure in the HM+DR group also became thinner, looser, and disordered, only a small number of microaneurysms were observed compared with the diabetic group. Immunohistochemical staining showed that the expression of OPN and integrin αvß 3 receptors in the diabetic groups (DR, HM+DR) was significantly higher than in the HM and NOR groups. The positive expression rates of OPN and integrin αvß 3 receptors in group HM+DR were significantly lower than those in group DR (P < 0.05). CONCLUSION: The expression of OPN and integrin αvß 3 receptor in the retina of diabetic guinea pigs with high myopia was lower than that of diabetic models, which may be due to the influence of high myopia on neovascularization in DR.

Dyadic appraisal and coping with illness among older Chinese adults with type 2 diabetes mellitus: a qualitative study.

INTRODUCTION: Diabetes management permeates patients' daily routines and interacts with their living context. Less is known about how older Chinese couples view their supportive roles and the allocation of the management responsibility between them. OBJECTIVES: To explore dyadic appraisal, coping and the barriers to diabetes management shared by older Chinese couples. METHODS: A qualitative study of older couples where at least one partner had type 2 diabetes mellitus was implemented in four communities of Guangzhou, China. Four focus groups containing 11 couples, and ten in-depth interviews with individual couples were conducted sequentially. All of the data were coded with Nvivo 11 using thematic analysis. RESULTS: The majority of the older couples interviewed appraised diabetes as a shared problem, taking part in monitoring and altering each other's health status and behaviour. Limited knowledge and a lack of accurate information about diabetes negatively impacted the patients' self-management and their spouse's ability to support them. A female dominated-care pattern was evident that female spouses, regardless of their health status, were actively involved in or fully responsible for managing their husband's health. Older couples' management practices were also shaped by family responsibilities and their living environment. CONCLUSIONS: Our study provides first-hand evidence of older Chinese couples' daily interactions and the main barriers to diabetes management. It is vital to provide health education directly to older couples to empower them to access adequate mutual support when managing chronic diseases.

Couple-based collaborative management model of type 2 diabetes mellitus for community-dwelling older adults in China: protocol for a hybrid type 1 randomized controlled trial.

BACKGROUND: China's limited health care resources cannot meet the needs of chronic disease treatment and management of its rapid growing ageing population. The improvement and maintenance of patient's self-management is essential to disease management. Given disease management mainly occurs in the context of family, this study proposes to validate a Couple-based Collaborative Management Model of chronic diseases that integrates health professionals and family supporters; such as to empower the couples with disease management knowledge and skills, and to improve the couples' health and quality of life. METHODS: The proposed study will validate a couple-based collaborative management model of Type 2 Diabetes Mellitus (T2DM) in a community-based multicenter, two-arm, randomized controlled trial of block design in Guangzhou, China. Specifically, 194 T2DM patients aged ≥55 and their partners recruited from community health care centers will be randomized at the patient level for each center at a 1:1 ratio into the couple-based intervention arm and the individual-based control arm. For the intervention arm, both the patients and their spouses will receive four-weekly structured group education & training sessions and 2 months of weekly tailored behavior change boosters; while these interventions will be only provided to the patients in the control group. Behavior change incentives will be targeted at the couples or only at the patient respectively. Treatment effects on patients' hemoglobin, spouses' quality of life, alongside couples' behavior outcomes will be compared between arms. Study implementation will be evaluated considering its Reach, Effectiveness, Adoption, Implementation and Maintenance following the RE-AIM framework. DISCUSSION: This study will generate a model of effective collaboration between community health professionals and patients' family, which will shield light on chronic disease management strategy for the increasing ageing population. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1900027137, Registered 1st Nov. 2019.

Examining income-related inequality in health literacy and health-information seeking among urban population in China.

BACKGROUND: Health literacy and health-information seeking behaviour (HISB) play vital roles in health outcome improvements. This study examines the extent of income-related inequality in health literacy and health-information seeking as well as the contributions of the main socioeconomic determinants in China. METHODS: We analysed representative data of participants aged over 18 years as well as older adults from the Guangzhou Community Health Survey. A concentration index (CI) was used to quantify the degree of income-related inequity in health literacy and health-information seeking. Probit regression models were employed to decompose the CI into the contributions to each factor. RESULTS: Results showed a significant pro-rich distribution of adequate health literacy (CI: 0.0602, P < 0.001; horizontal index [HI]: 0.0562, P < 0.001) and HISB from healthcare professionals (CI: 0.105, P < 0.001; HI: 0.0965, P < 0.001). The pro-rich distribution of health literacy was mainly attributable to education background (contribution: 54.76%), whereas income inequalities contributed most to the pro-rich distribution of health-information seeking among an urban population (contribution: 62.53%). CONCLUSION: Public interventions in China to reduce inequality in health literacy and HISBs among the urban population, coupled with easily accessible information sources on health, warrant further attention from policymakers.

Distinct effects of mutations on biophysical properties of human prion protein monomers and oligomers.

Prion diseases are a group of fatal neurodegenerative illnesses, resulting from the conformational conversion of the cellular prion protein (PrPC) into a misfolded form (PrPSc). The formation of neurotoxic soluble prion protein oligomer (PrPO) is regarded as a key step in the development of prion diseases. About 10%-15% of human prion diseases are caused by mutations in the prion protein gene; however, the underlying molecular mechanisms remain unclear. In the present work, we compared the biophysical properties of wild-type (WT) human prion protein 91-231 (WT HuPrP91-231) and its disease-associated variants (P105L, D178N, V203I, and Q212P) using several biophysical techniques. In comparison with WT HuPrPC, the Q212P and D178N variants possessed greatly increased conversion propensities of PrPC into PrPO, while the V203I variant had dramatically decreased conversion propensity. The P105L variant displayed a similar conversion propensity to WT HuPrPC Guanidine hydrochloride-induced unfolding experiments ranked the thermodynamic stabilities of these proteins as Q212P < D178N < WT ≈ P105L < V203I. It was thus suggested that the conversion propensities of the prion proteins are closely associated with their thermodynamic stabilities. Furthermore, structural comparison illustrated that Q212P, D178N, and V203I variants underwent larger structural changes compared with WT HuPrPC, while the P105L variant adopted a similar structure to the WT HuPrPC The mutation-induced structural perturbations might change the thermodynamic stabilities of the HuPrPC variants, and correspondingly alter the conversion propensities for these prion proteins. Our results extend the mechanistic understanding of prion pathogenesis, and lay the basis for the prevention and treatment of prion diseases.

Diverse specificity and effector function among human antibodies to HIV-1 envelope glycoprotein epitopes exposed by CD4 binding.

The HIV-1 envelope glycoprotein (Env) undergoes conformational transitions consequent to CD4 binding and coreceptor engagement during viral entry. The physical steps in this process are becoming defined, but less is known about their significance as targets of antibodies potentially protective against HIV-1 infection. Here we probe the functional significance of transitional epitope exposure by characterizing 41 human mAbs specific for epitopes exposed on trimeric Env after CD4 engagement. These mAbs recognize three epitope clusters: cluster A, the gp120 face occluded by gp41 in trimeric Env; cluster B, a region proximal to the coreceptor-binding site (CoRBS) and involving the V1/V2 domain; and cluster C, the coreceptor-binding site. The mAbs were evaluated functionally by antibody-dependent, cell-mediated cytotoxicity (ADCC) and for neutralization of Tiers 1 and 2 pseudoviruses. All three clusters included mAbs mediating ADCC. However, there was a strong potency bias for cluster A, which harbors at least three potent ADCC epitopes whose cognate mAbs have electropositive paratopes. Cluster A epitopes are functional ADCC targets during viral entry in an assay format using virion-sensitized target cells. In contrast, only cluster C contained epitopes that were recognized by neutralizing mAbs. There was significant diversity in breadth and potency that correlated with epitope fine specificity. In contrast, ADCC potency had no relationship with neutralization potency or breadth for any epitope cluster. Thus, Fc-mediated effector function and neutralization coselect with specificity in anti-Env antibody responses, but the nature of selection is distinct for these two antiviral activities.

Structural definition of an antibody-dependent cellular cytotoxicity response implicated in reduced risk for HIV-1 infection.

UNLABELLED: The RV144 vaccine trial implicated epitopes in the C1 region of gp120 (A32-like epitopes) as targets of potentially protective antibody-dependent cellular cytotoxicity (ADCC) responses. A32-like epitopes are highly immunogenic, as infected or vaccinated individuals frequently produce antibodies specific for these determinants. Antibody titers, as measured by enzyme-linked immunosorbent assay (ELISA) against these epitopes, however, do not consistently correlate with protection. Here, we report crystal structures of CD4-stabilized gp120 cores complexed with the Fab fragments of two nonneutralizing, A32-like monoclonal antibodies (MAbs), N5-i5 and 2.2c, that compete for antigen binding and have similar antigen-binding affinities yet exhibit a 75-fold difference in ADCC potency. We find that these MAbs recognize overlapping epitopes formed by mobile layers 1 and 2 of the gp120 inner domain, including the C1 and C2 regions, but bind gp120 at different angles via juxtaposed VH and VL contact surfaces. A comparison of structural and immunological data further showed that antibody orientation on bound antigen and the capacity to form multivalent antigen-antibody complexes on target cells were key determinants of ADCC potency, with the latter process having the greater impact. These studies provide atomic-level definition of A32-like epitopes implicated as targets of protective antibodies in RV144. Moreover, these studies establish that epitope structure and mode of antibody binding can dramatically affect the potency of Fc-mediated effector function against HIV-1. These results provide key insights for understanding, refining, and improving the outcome of HIV vaccine trials, in which relevant immune responses are facilitated by A32-like elicited responses. IMPORTANCE: HIV-1 Env is a primary target for antibodies elicited during infection. Although a small number of infected individuals elicit broadly neutralizing antibodies, the bulk of the humoral response consists of antibodies that do not neutralize or do so with limited breadth but may effect protection through Fc receptor-dependent processes, such as antibody-dependent cellular cytotoxicity (ADCC). Understanding these nonneutralizing responses is an important aspect of elucidating the complete spectrum of immune response against HIV-1 infection. With this report, we provide the first atomic-level definition of nonneutralizing CD4-induced epitopes in the N-terminal region of the HIV-1 gp120 (A32-like epitopes). Further, our studies point to the dominant role of precise epitope targeting and mode of antibody attachment in ADCC responses even when largely overlapping epitopes are involved. Such information provides key insights into the mechanisms of Fc-mediated function of antibodies to HIV-1 and will help us understand the outcome of vaccine trials based on humoral immunity.

Palladium-catalyzed air-based oxidative coupling of arylboronic acids with H-phosphine oxides leading to aryl phosphine oxides.

We present a novel and highly efficient methodology that allows for the construction of C-P bonds via the palladium-catalyzed air-based oxidative coupling of various commercially available arylboronic acids with easily oxidized H-phosphine oxides leading to valuable aryl phosphine oxides, particularly triarylphosphine oxides, with the use of air as the green oxidant, broad substrate applicability and good to excellent yields. The described catalytic system should be an efficient complement to the Chan-Lam type reaction and be useful in synthetic programs.

Gender difference in association of NEDD4L gene variants among southern Han Chinese with essential hypertension - a population-based case-control study.

Genetic variation of NEDD4L has been associated with hypertension and related phenotypes with conflicting results, probably attributable to gender-, age- and ethnicity-related variations in its phenotypic expression. We evaluated the association of three representative polymorphisms in NEDD4L (rs2288774, rs3865418 and rs4149601) with essential hypertension (EH) in a community-based sample of men (n = 1029) and women (n = 869) belonging to Han Chinese, Southern China, to probe whether gender interacts with NEDD4L in contributing to the risk of EH. In this population sample, rs4149601 was excluded from further analysis due to deviation from Hardy-Weinberg equilibrium. For two other variants tested, the allele frequencies and genotype distributions did not differ between cases and controls (p > 0.05) when both genders were combined. However, sex-stratified analysis revealed that the distribution of the dominant model of rs2288774 (TC + CC versus TT) and the additive and dominant (CT + TT versus CC) models of rs3865418 differed significantly between cases and controls in men (p = 0.044, 0.041 and 0.016, respectively) but not in women. After adjusting for confounding factors, logistic regression analysis showed that rs2288774 and rs3865418 (in the dominant model) were still significantly associated with EH (rs2288774: OR = 0.73, 95% CI = 0.57-0.95, p = 0.017 and rs3865418: OR = 0.71, 95% CI = 0.55-0.92, p = 0.009) in men. There was a significant interaction between the NEDD4L genotype and gender (p for interaction: 0.046 for rs2288774 and 0.033 for rs3865418). Genetic variation in NEDD4L may have sex-dependent effects in the development of EH in Han Chinese. Previous studies that ignore gender-specific effects in their design and interpretation could have failed to identify a uniform conclusion.

Useful information for hypertension management reform in community health care: prevalence, awareness, treatment and control among Guangzhou adults.

BACKGROUND: Objective data on hypertension prevalence and management in local areas are scarce. We assessed the prevalence of hypertension and its management in Guangzhou adult population. METHODS: A stratified multistage cluster sampling with probability proportional to size method was used in this survey. Information on a total of 23 939 respondents, aged 15 years old or above, having a gender ratio of 0.997 (male versus female) with completed questionnaire and blood pressure measurement, was obtained. Hypertension was defined as having a mean SBP of at least 140 mm Hg, a DBP of at least 90 mm Hg, and/or the prescription of antihypertensive drugs. Information related to the history of hypertension and treatment of hypertension was collected through a questionnaire. RESULTS: The prevalence of hypertension was 11.8%. Among patients with hypertension, 54.4% were aware of their elevated BP, 49.3% had treatment, and 23.3% achieved targeted BP control. Among those who were aware of their hypertension, 90.4% underwent treatment, and among those who were treated, 43.6% were well controlled. Although the prevalence, awareness and treatment of hypertension varied significantly among adults with several social economics status, the control of hypertension did not show significant differences. Among treated patients, the control of hypertension showed significant differences among adults with education, occupation, insurance and income. CONCLUSIONS: It is the first time for Guangzhou to describe epidemic and management of hypertension. A baseline was established, which could provide useful information not only to policymakers but also to developing countries with a close urbanization and aging rate similar to Guangzhou.

Prevalence of noncommunicable diseases and their risk factors in Guangzhou, China.

INTRODUCTION: This article reports on the prevalence of noncommunicable diseases (NCDs) and their risk factors in the city of Guangzhou, China, and shows a trend toward epidemic proportions when municipal data are compared with provincial data. METHODS: We conducted the Guangzhou Community Health Survey in the 12 administrative districts of Guangzhou to learn about NCDs and their risk factors. A community-based, face-to-face survey with a stratified multistage cluster sampling was used. Information was gathered on 27,743 respondents, aged 0 to 108 years, with a male to female ratio of 1 to 1. All participants completed a questionnaire, and those aged 15 years or older had a physical examination. Survey results were compared with the provincial results of the 2002 Guangdong Nutrition and Health Survey (GNHS). RESULTS: The data were weighted to the respondent's probability of selection and to the age- and sex-specific population. Prevalence estimate of self-reported NCDs was 16.0%. Hypertension and diabetes were reported as the most important NCDs. Of those who responded, 6.8% reported having more than 2 chronic conditions. The adjusted prevalence of hypertension decreased by 13.3% since 2002. Awareness, treatment, and control of hypertension and diabetes were improved. The estimated prevalence of current smoking decreased, and the prevalence of former smoking increased from 2002. However, the prevalence of overweight and obesity, especially central obesity, increased. CONCLUSION: Results were encouraging with regard to hypertension and diabetes. However, the unfavorable trends, especially for overweight, central obesity, and passive smoking, call for additional action.

Atypical inflammatory kinase IKBKE phosphorylates and inactivates FoxA1 to promote liver tumorigenesis.

Physiologically, FoxA1 plays a key role in liver differentiation and development, and pathologically exhibits an oncogenic role in prostate and breast cancers. However, its role and upstream regulation in liver tumorigenesis remain unclear. Here, we demonstrate that FoxA1 acts as a tumor suppressor in liver cancer. Using a CRISPR-based kinome screening approach, noncanonical inflammatory kinase IKBKE has been identified to inhibit FoxA1 transcriptional activity. Notably, IKBKE directly binds to and phosphorylates FoxA1 to reduce its complex formation and DNA interaction, leading to elevated hepatocellular malignancies. Nonphosphorylated mimic Foxa1 knock-in mice markedly delay liver tumorigenesis in hydrodynamic transfection murine models, while phospho-mimic Foxa1 knock-in phenocopy Foxa1 knockout mice to exhibit developmental defects and liver inflammation. Notably, Ikbke knockout delays diethylnitrosamine (DEN)-induced mouse liver tumor development. Together, our findings not only reveal FoxA1 as a bona fide substrate and negative nuclear effector of IKBKE in hepatocellular carcinioma (HCC) but also provide a promising strategy to target IKBEK for HCC therapy.

Functional determinants of human enteric α-defensin HD5: crucial role for hydrophobicity at dimer interface.

Human α-defensins are cationic peptides that self-associate into dimers and higher-order oligomers. They bind protein toxins, such as anthrax lethal factor (LF), and kill bacteria, including Escherichia coli and Staphylococcus aureus, among other functions. There are six members of the human α-defensin family: four human neutrophil peptides, including HNP1, and two enteric human defensins, including HD5. We subjected HD5 to comprehensive alanine scanning mutagenesis. We then assayed LF binding by surface plasmon resonance, LF activity by enzyme kinetic inhibition, and antibacterial activity by the virtual colony count assay. Most mutations could be tolerated, resulting in activity comparable with that of wild type HD5. However, the L29A mutation decimated LF binding and bactericidal activity against Escherichia coli and Staphylococcus aureus. A series of unnatural aliphatic and aromatic substitutions at position 29, including aminobutyric acid (Abu) and norleucine (Nle) correlated hydrophobicity with HD5 function. The crystal structure of L29Abu-HD5 depicted decreased hydrophobic contacts at the dimer interface, whereas the Nle-29-HD5 crystal structure depicted a novel mode of dimerization with parallel ß strands. The effect of mutating Leu(29) is similar to that of a C-terminal hydrophobic residue of HNP1, Trp(26). In addition, in order to further clarify the role of dimerization in HD5 function, an obligate monomer was generated by N-methylation of the Glu(21) residue, decreasing LF binding and antibacterial activity against S. aureus. These results further characterize the dimer interface of the α-defensins, revealing a crucial role of hydrophobicity-mediated dimerization.

Invariant gly residue is important for α-defensin folding, dimerization, and function: a case study of the human neutrophil α-defensin HNP1.

The human α-defensins (HNP) are synthesized in vivo as inactive prodefensins, and contain a conserved glycine, Gly(17), which is part of a ß-bulge structure. It had previously been shown that the glycine main chain torsion angles are in a D-configuration, and that d-amino acids but not L-alanine could be substituted at that position to yield correctly folded peptides without the help of a prodomain. In this study, the glycine to L-alanine mutant defensin was synthesized in the form of a prodefensin using native chemical ligation. The ligation product folded correctly and yielded an active peptide upon CNBr cleavage. The L-Ala(17)-HNP1 crystal structure depicted a ß-bulge identical to wild-type HNP1. However, dimerization was perturbed, causing one monomer to tilt with respect to the other in a dimerization model. Inhibitory activity against the anthrax lethal factor showed a 2-fold reduction relative to wild-type HNP1 as measured by the inhibitory concentration IC(50). Self-association was slightly reduced, as detected by surface plasmon resonance measurements. According to the results of the virtual colony count assay, the antibacterial activity against Escherichia coli, Staphylococcus aureus, and Bacillus cereus exhibited a less than 2-fold reduction in virtual lethal dose values. Prodefensins with two other L-amino acid substitutions, Arg and Phe, at the same position did not fold, indicating that only small side chains are tolerable. These results further elucidate the factors governing the region of the ß-bulge structure that includes Gly(17), illuminating why glycine is conserved in all mammalian α-defensins.

Biochemical characterization and ligand-binding properties of trehalose-6-phosphate phosphatase from Mycobacterium tuberculosis.

Trehalose-6-phosphate phosphatase (TPP) is an essential enzyme for growth of mycobacteria, which has been identified to be a potential anti-tuberculosis drug target. However, the biochemical and ligand-binding properties and the 3D structure of TPP remain unclear so far. In the present study, we expressed the recombinant TPP protein from Mycobacterium tuberculosis (otsB2/Rv3372). Results from the far-ultraviolet circular dichroism experiments indicated that the secondary structure of TPP was rich in α-helix with a lower structural stability (Cm = 2.099 ± 0.134 M). Ligand-binding assay by isothermal titration calorimetry demonstrated that the recombinant TPP protein could bind with trehalose-6-P in the presence of Mg(2+) (Kd = 39.52 ± 1.78 µM) with a molar ratio of 1 : 1. In addition, the 3D structure of TPP was modeled by I-TASSER, indicating that the TPP protein was composed of a hydrolase domain, a cap domain, and an N-terminal domain. Flexible docking was further conducted by using the Simulations/Dock module of the Molecular Operating Environment software. The binding pocket of TPP for both trehalose-6-P and Mg(2+) was determined, which was located on the interface between the hydrolase domain and the cap domain. Asp149, Gly186, Arg187, Arg291, and Glu295 were identified to be the key residues for TPP binding with trehalose-6-P. This work may lay the basis for further structural and functional studies of TPP and TPP-related novel drug development.

A functional variant of NEDD4L is associated with obesity and related phenotypes in a Han population of Southern China.

NEDD4L is a candidate gene for hypertension, both functionally and genetically. Recently, studies showed evidence for the association of NEDD4L with obesity, a key intermediate phenotype in hypertension. To further investigate the relationship between NEDD4L and body mass-related phenotypes, we genotyped three common variants (rs2288774, rs3865418 and rs4149601) in a population-based study of 892 unrelated Han Cantonese using the Sequenom MALDI-TOF-MS platform. Allele frequencies and genotype distribution were calculated in lean controls and overweight/obese cases and analyzed for association by the Chi-squared test and Logistic regression. Linear regression analysis was used to analyze the effect of individual genotypes on quantitative traits. Multivariate analyses demonstrated that the minor allele of rs4149601(A = 20.9%) was associated with a 2.60 kg, 2.78 cm and 0.97 kg/m2 decrease per allele copy in weight, waist and BMI, respectively. Carriers of this allele also had a significant lower risk of overweight/obesity (p < 0.0001, OR = 0.52, 95% CI: 0.37-0.74) as compared to non-carriers. However, no significant association between genotypes at rs2288774 and rs3865418 and covariate-adjusted overweight/obesity or any related phenotypes was observed. These results suggested that the functional variant of NEDD4L, rs4149601, may be associated with obesity and related phenotypes, and further genetic and functional studies are required to understand its role in the manifestation of obesity.

Beyond controlling cell size: functional analyses of S6K in tumorigenesis.

As a substrate and major effector of the mammalian target of rapamycin complex 1 (mTORC1), the biological functions of ribosomal protein S6 kinase (S6K) have been canonically assigned for cell size control by facilitating mRNA transcription, splicing, and protein synthesis. However, accumulating evidence implies that diverse stimuli and upstream regulators modulate S6K kinase activity, leading to the activation of a plethora of downstream substrates for distinct pathobiological functions. Beyond controlling cell size, S6K simultaneously plays crucial roles in directing cell apoptosis, metabolism, and feedback regulation of its upstream signals. Thus, we comprehensively summarize the emerging upstream regulators, downstream substrates, mouse models, clinical relevance, and candidate inhibitors for S6K and shed light on S6K as a potential therapeutic target for cancers.

Gender-Specific Effect of Couple-Based Intervention on Behavioral and Psychological Outcomes of Older Adults with Type 2 Diabetes during the COVID-19 Partial Lockdown in Guangzhou, China.

This study aimed to evaluate the gender-specific effect of a couple-based intervention on the management behaviors and mental well-being of community-dwelling older adults with type 2 diabetes mellitus during the COVID-19 partial lockdown in Guangzhou. Out of 207 participants involved in a prior randomized controlled trial (Trial no. ChiCTR1900027137), 156 (75%) completed the COVID-19 survey. Gendered differences in management behaviors and depressive symptoms between the couple-based intervention group and the patient-only control group were compared by distance to the high-risk areas cross-sectionally and longitudinally using random intercept models. Cross-sectionally, female patients of the intervention group had more positive behavior change scores (ß = 1.53, p = 0.002) and fewer depressive symptoms (ß = −1.34, p = 0.02) than the control group. Over time, female patients lived closer to the high-risk areas (<5 km) and showed decreasing depressive symptoms (ß = −4.48, p = 0.008) in the intervention group vs. the control group. No statistically significant between-group difference was found for males. Females tended to benefit more from the coupled-based intervention than males did, particularly among these closer to the high-risk areas. Chronic disease management can be better sustained with active spousal engagement.