GM1 ganglioside protects against LPS-induced neuroinflammatory and oxidative responses by inhibiting the activation of Akt, TAK1 and NADPH oxidase in MG6 microglial cells.

GM1 is a major brain ganglioside that exerts neurotrophic, neuroprotective and antineuroinflammatory effects. The aim of this study was to obtain insights into the antineuroinflammatory mechanisms of exogenous GM1 in lipopolysaccharide (LPS)-stimulated MG6 mouse transformed microglial cell line. First, we found that GM1 prevented the LPS-induced transformation of microglia into an amoeboid-like shape. GM1 treatment inhibited LPS-induced expression of inducible nitric oxide synthase, cyclooxygenase-2 (COX-2), and proinflammatory cytokines such as TNF-α, IL-1ß and IL-6 in MG6 cells. In LPS-treated mice, GM1 also reduced striatal microglia activation and attenuated COX-2 expression. Subsequent mechanistic studies showed that GM1 suppressed LPS-induced nuclear translocation of nuclear factor κB (NF-κB) and activator protein-1 (AP-1), two critical transcription factors responsible for the production of proinflammatory mediators. GM1 exhibited antineuroinflammatory properties by suppressing Akt/NF-κB signaling and the activation of mitogen-activated protein kinases (MAPKs), including p38 MAPK, extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Furthermore, GM1 suppressed LPS-induced activation of transforming growth factor-ß-activated kinase 1 (TAK1) and NADPH oxidase 2 (NOX2), upstream regulators of the IκBα/NF-κB and MAPK/AP-1 signaling pathways. GM1 also inhibited NOX-mediated reactive oxygen species (ROS) production and protected against LPS-induced MG6 cell death, suggesting an antioxidant role of GM1. In conclusion, GM1 exerts both antineuroinflammatory and antioxidative effects by inhibiting Akt, TAK1 and NOX2 activation.

The outcomes of aortic arch repair between open surgical repair and debranching endovascular hybrid surgical repair: A systematic review and meta-analysis.

BACKGROUND: At present, open surgical aortic arch repair (OAR) and debranching hybrid surgical aortic arch repair (HAR) serve as significant therapeutic approaches for aortic arch aneurysm or dissection. It remains unclear which technique is preferable. Our study aimed to compare the short-term and long-term outcomes of these two procedures. METHODS: To identify comparison studies of debranching HAR and OAR, a systematic search of the PubMed, Embase, Web of Science, and Cochrane Library databases was performed from January 2002 to April 2022. This study was registered on PROSPERO (CRD42020218080). RESULTS: Sixteen publications (1316 patients), including six propensity score-matching (PSM) analysis papers, were included in this study. Compared with the HAR group, the patients who underwent OAR were younger (OAR vs HAR: 67.53 ± 12.81 vs 71.29 ± 11.0; P < .00001), had less coronary artery disease (OAR vs HAR: 22.45% vs 32.6%; P = .007), less chronic obstructive pulmonary disease (OAR vs HAR: 16.16% vs 23.92%; P = .001), lower rates of previous stroke (OAR vs HAR: 12.46% vs 18.02%; P = .05), and a lower EuroSCORE (European System for Cardiac Operative Risk Evaluation) score (OAR vs HAR: 6.27 ± 1.04 vs 6.9 ± 3.76; P < .00001). HAR was associated with less postoperative blood transfusion (OAR vs HAR: 12.23% vs 7.91%; P = .04), shorter length of intensive care unit stays (OAR vs HAR: 5.92 ± 7.58 days vs 4.02 ± 6.60 days; P < .00001) and hospital stays (OAR vs HAR: 21.59 ± 17.54 days vs 16.49 ± 18.45 days; P < .0001), lower incidence of reoperation for bleeding complications (OAR vs HAR: 8.07% vs 3.96%; P = .01), fewer postoperative pulmonary complication (OAR vs HAR: 14.75% vs 5.02%; P < .0001), and acute renal failure (OAR vs HAR: 7.54% vs 5.17%; P = .03). In the PSM subgroup, the rates of spinal cord ischemic (OAR vs HAR: 5.75% vs 11.49%; P = .02), stroke (OAR vs HAR: 5.1% vs 17.35%; P = .01), and permanent paraplegia (OAR vs HAR: 2.79% vs 6.08%; P = .006) were lower in the OAR group than that in the HAR group. Although there was no statistically significant difference in 1-year survival rates (HAR vs OAR: hazard ratio [HR]: 1.54; P = .10), the 3-year and 5-year survivals were significantly higher in the OAR group than that in the HAR group (HAR vs OAR: HR: 1.69; P = .01; HAR vs OAR: HR: 1.68; P = .01). In the PSM subgroup, the OAR group was also significantly superior to the HAR group in terms of 3-year and 5-year survivals (HAR vs OAR: HR: 1.73; P = .04; HAR vs OAR: HR: 1.67; P = .04). The reintervention rate in the HAR group was significantly higher than that in the OAR group (OAR vs HAR: 8.24% vs 16.01%; P = .01). The most common reintervention was postoperative bleeding (8.07%) in the OAR group and endoleak (9.67%) in the HAR group. CONCLUSIONS: Our meta-analysis revealed that debranching HAR was associated with fewer perioperative complications than the OAR group, except for postoperative permanent paraplegia, reintervention, and stroke events. The OAR group demonstrated better 3-year and 5-year survivals than the debranching HAR group. However, patients in the OAR group had fewer comorbid factors and were younger than those in the HAR group. High-quality studies and well-powered randomized trials are needed to further evaluate this evolving field.

Three-metal ion mechanism of cross-linked and uncross-linked DNA polymerase ß: A theoretical study.

In our recent publication, we have proposed a revised base excision repair pathway in which DNA polymerase ß (Polß) catalyzes Schiff base formation prior to the gap-filling DNA synthesis followed by ß-elimination. In addition, the polymerase activity of Polß employs the "three-metal ion mechanism" instead of the long-standing "two-metal ion mechanism" to catalyze phosphodiester bond formation based on the fact derived from time-resolved x-ray crystallography that a third Mg2+ was captured in the polymerase active site after the chemical reaction was initiated. In this study, we develop the models of the uncross-linked and cross-linked Polß complexes and investigate the "three-metal ion mechanism" vs the "two-metal ion mechanism" by using the quantum mechanics/molecular mechanics molecular dynamics simulations. Our results suggest that the presence of the third Mg2+ ion stabilizes the reaction-state structures, strengthens correct nucleotide binding, and accelerates phosphodiester bond formation. The improved understanding of Polß's catalytic mechanism provides valuable insights into DNA replication and damage repair.

Nano-Si for On-Demand H2 Production: Optimization of Yield and Real-Time Visualization of Si─H2 O Reaction Using Liquid-Phase Transmission Electron Microscopy.

Hydrogen (H2 ), the most abundant element in the universe, has the potential to address the challenges of energy security and climate change. However, due to the lack of a safe and efficient method for storing and delivering hydrogen, its practical application is still in its infancy stages. To overcome this challenge, a promising solution is demonstrated in the form of on-demand production of H2 using nano-Silicon (Si) powders. The method offers instantaneous production of H2 , yielding a volume of 1.3 L per gram of Si at room temperature. Moreover, the H2 production yield and the rate can be effectively controlled by adjusting the reaction pH value and temperatures. Additionally, liquid-phase transmission electron microscopy (LPTEM) is utilized in situ to demonstrate the entire reaction in real-time, wherein H2 bubble formation is observed and illustrated the gradual conversion of crystalline Si particles into amorphous oxides. Moreover, it is confirmed that the purity of the generated gas is 99.5% using gas chromatography mass spectrometry (GC-MS). These findings suggest a viable option for instant H2 production in portable fuel cells using Si cartridges or pellets.

Impact of SGLT2 inhibitors on patient outcomes: a network meta-analysis.

BACKGROUND: A comprehensive network meta-analysis comparing the effects of individual sodium-glucose cotransporter 2 (SGLT2) inhibitors on patients with and without comorbidities including diabetes mellitus (DM), heart failure (HF), and chronic kidney disease (CKD) has not been previously conducted. METHODS: We searched PubMed, Embase, Cochrane, and ClinicalTrials.gov for randomized controlled trials up to March 28, 2023. Network meta-analysis using a random-effects model was conducted to calculate risk ratios (RRs). Risk of Bias tool 2.0 was used to assess bias, and CINeMA to assess the certainty of evidence. In the subgroup analysis, the SGLT2 inhibitors were classified into highly (dapagliflozin, empagliflozin, and ertugliflozin) and less selective SGLT2 inhibitors (canagliflozin and sotagliflozin). RESULTS: A total of fourteen trials with 75,334 patients were analyzed. Among these, 40,956 had taken SGLT2 inhibitors and 34,378 had not. One of the main results with particular findings was empagliflozin users had a significantly lower risk of all-cause death compared to dapagliflozin users in DM population (RR: 0.81, 95% CI 0.69-0.96). In HF population, sotagliflozin users had a borderline significantly lower risk of CV death or hospitalization for HF (HHF) than dapagliflozin users (RR: 0.90, 95% CI 0.80-1.01). In non-HF population, those who used canagliflozin had a significantly lower risk of CV death or HHF compared with those who used dapagliflozin (RR: 0.75, 95% CI 0.58-0.98). At last, for HF patients, those who used less selective SGLT2 inhibitors had a significantly lower risk of MACEs compared to those who used highly selective SGLT2 inhibitors (RR: 0.75, 95% CI 0.62-0.90). CONCLUSIONS: Our network meta-analysis revealed that empagliflozin users with diabetes experienced a lower risk of dying from any cause than those using dapagliflozin. Additionally, canagliflozin users demonstrated a reduced risk of cardiovascular death or HHF compared to dapagliflozin users in those without HF. In HF patients, less selective SGLT2 inhibitors showed superior CV composite outcomes, even surpassing the performance of highly selective SGLT2 inhibitors. TRIAL REGISTRATION: PROSPERO [CRD42022361906].

Guillain-Barre syndrome after myocardial infarction: a case report and literature review.

BACKGROUND: Guillain-Barre syndrome after myocardial infarction occurs infrequently, and its occurrence following percutaneous coronary intervention is extremely rare. Due to the high mortality rate of myocardial infarction and the disability of Guillain-Barre syndrome, early identification of Guillain-Barre syndrome after myocardial infarction and early intervention can decrease the mortality rate, lead to early recovery, and provide a better outcome. CASE PRESENTATION: Herein, we reported a rare case of Guillain-Barre syndrome after myocardial infarction treated with percutaneous coronary intervention. The patient was a 75-year-old woman from China who was admitted to hospital due to sudden loss of consciousness. Electrocardiography showed acute myocardial infarction in the right ventricle and inferior and posterior walls. The patient underwent emergency percutaneous intervention of the posterior collateral artery of the right coronary artery. Soon after, her condition worsened resulting in limb weakness and numbness. Unfortunately, she continued to develop respiratory failure, and treated with intravenous immunoglobulin and ventilator-assisted breathing. A physical examination showed hypotonia of all four limbs, complete quadriplegia, bulbar palsy, dysarthria, and tendon areflexia. Serum immunoglobulin (Ig) G anti-ganglioside antibody analysis was positive with anti-GT1a antibodies (+ +), anti-GM1 antibodies ( +), anti-GM2 antibodies ( +), and anti-GM4 antibodies ( +), and he was diagnosed with Guillain-Barre syndrome after myocardial infarction. She was discharged due to poor response to treatment. The patient died two days after being discharged. CONCLUSIONS: Myocardial infarction and/or percutaneous coronary intervention may activate immune-mediated response and cause severe complications. Clinician should be alert to Guillain-Barre syndrome after myocardial infarction and/or percutaneous coronary intervention.

Cohort Profile: Guangzhou Nutrition and Health Study (GNHS): A Population-Based Multi-Omics Study.

BACKGROUND: The Guangzhou Nutrition and Health Study (GNHS) aims to assess the determinants of metabolic disease in nutritional aspects, as well as other environmental and genetic factors, and explore possible biomarkers and mechanisms with multi-omics integration. METHODS: The population-based sample of adults in Guangzhou, China (baseline: 40-83 years old; n = 5118) was followed up about every 3 years. All will be tracked via on-site follow-up and health information systems. We assessed detailed information on lifestyle factors, physical activities, dietary assessments, psychological health, cognitive function, body measurements, and muscle function. Instrument tests included dual-energy X-ray absorptiometry scanning, carotid artery and liver ultrasonography evaluations, vascular endothelial function evaluation, upper-abdomen and brain magnetic resonance imaging, and 14-d real-time continuous glucose monitoring tests. We also measured multi-omics, including host genome-wide genotyping, serum metabolome and proteome, gut microbiome (16S rRNA sequencing, metagenome, and internal transcribed spacer 2 sequencing), and fecal metabolome and proteome. RESULTS: The baseline surveys were conducted from 2008 to 2015. Now, we have completed 3 waves. The 3rd and 4th follow-ups have started but have yet to end. A total of 5118 participants aged 40-83 took part in the study. The median age at baseline was approximately 59.0 years and the proportion of female participants was about 69.4%. Among all the participants, 3628 (71%) completed at least one on-site follow-up with a median duration of 9.48 years. CONCLUSION: The cohort will provide data that have been influential in establishing the role of nutrition in metabolic diseases with multi-omics.

Investigations of the underlying mechanisms of HIF-1α and CITED2 binding to TAZ1.

The TAZ1 domain of CREB binding protein is crucial for transcriptional regulation and recognizes multiple targets. The interactions between TAZ1 and its specific targets are related to the cellular hypoxic negative feedback regulation. Previous experiments reported that one of the TAZ1 targets, CITED2, is an efficient competitor of another target, HIF-1α. Here, by developing the structure-based models of TAZ1 complexes, we have uncovered the underlying mechanisms of the competitions between the two intrinsic disordered proteins (IDPs) HIF-1α and CITED2 binding to TAZ1. Our results support the experimental hypothesis on the competition mechanisms and the apparent affinity. Furthermore, the simulations locate the dominant position of forming TAZ1-CITED2 complex in both thermodynamics and kinetics. For thermodynamics, TAZ1-CITED2 is the lowest basin located on the free energy surface of binding in the ternary system. For kinetics, the results suggest that CITED2 binds to TAZ1 faster than HIF-1α. In addition, the analysis of contact map and Φ values is important for guiding further experimental studies to understand the biomolecular functions of IDPs.

Sintering Behaviors of Supported Nanoparticles Related to Spatial Location by a Quasi-Four-Dimensional TEM.

The performance degradation via sintering phenomenon is a critical issue for the application of supported nanoparticles in industrial catalysis. However, the challenges to combine in situ stimulation and three-dimensional (3D) characterization hinder a profound understanding of sintering behaviors, thus the effect of spatial location on nanoparticles sintering has long been neglected. Herein, based on a homemade holder integrated with in situ Joule heating and electron tomography, a quasi-four-dimensional (4D) transmission electron microscope characterization approach is developed to reveal the spatial location of supported nanoparticles and its pronounced impact on size distribution and sintering behaviors. The results of 3D visualization and statistical analysis demonstrate a strong location-dependent sintering behavior of supported nanoparticles, where external nanoparticles sinter via migration coalescence, and internal nanoparticles sinter via Ostwald ripening. The quasi-4D methods developed in this work can also be extended to the study on 3D configuration evolution of other nanomaterials under an external stimulus.

Kazinol B protects H9c2 cardiomyocytes from hypoxia/reoxygenation-induced cardiac injury by modulating the AKT/AMPK/Nrf2 signalling pathway.

CONTEXT: Kazinol B (KB), an isoprenylated flavan derived from Broussonetia kazinoki Sieb. (Moraceae) root, has long been used in folk medicine. OBJECTIVE: This study examines the protective effects of KB and its underlying mechanisms in hypoxia and reoxygenation (H/R)-induced cardiac injury in H9c2 rat cardiac myoblasts. MATERIALS AND METHODS: H9c2 cells were incubated with various concentrations of KB (0, 0.3, 1, 3, 10 and 30 µM) for 2 h and then subjected to H/R insults. The protective effects of KB and its underlying mechanisms were explored. RESULTS: KB significantly elevated cell viability (1 µM, 1.21-fold; 3 µM, 1.36-fold, and 10 µM, 1.47-fold) and suppressed LDH release (1 µM, 0.77-fold; 3 µM, 0.68-fold, and 10 µM, 0.59-fold) in H/R-induced H9c2 cells. Further, 10 µM KB blocked apoptotic cascades, as shown by the Annexin-V/PI (0.41-fold), DNA fragmentation (0.51-fold), caspase-3 (0.52-fold), PARP activation (0.27-fold) and Bax/Bcl-2 expression (0.28-fold) assays. KB (10 µM) downregulated reactive oxygen species production (0.51-fold) and lipid peroxidation (0.48-fold); it upregulated the activities of GSH-Px (2.08-fold) and SOD (1.72-fold). KB (10 µM) induced Nrf2 nuclear accumulation (1.94-fold) and increased ARE promoter activity (2.15-fold), HO-1 expression (3.07-fold), AKT (3.07-fold) and AMPK (3.07-fold) phosphorylation. Nrf2 knockdown via using Nrf2 siRNA abrogated KB-mediated protective effects against H/R insults. Moreover, pharmacological inhibitors of AKT and AMPK also abrogated KB-induced Nrf2 activation and its protective function. DISCUSSION AND CONCLUSIONS: KB prevented H/R-induced cardiomyocyte injury via modulating the AKT and AMPK-mediated Nrf2 induction. KB might be a promising drug candidate for managing ischemic cardiac disorders.

Tetrabutylammonium Halides as Selectively Bifunctional Catalysts Enabling the Syntheses of Recyclable High Molecular Weight Salicylic Acid-Based Copolyesters.

To synthesize high molecular weight poly(phenolic ester) via a living ring-opening polymerization (ROP) of cyclic phenolic ester monomers remains a critical challenge due to serious transesterification and back-biting reactions. Both phenolic ester bonds in monomer and polymer chains are highly active, and it is difficult so far to distinguish them. In this work, an unprecedented selectively bifunctional catalytic system of tetra-n-butylammonium chloride (TBACl) was discovered to mediate the syntheses of high molecular weight salicylic acid-based copolyesters via a living ROP of salicylate cyclic esters (for poly(salicylic methyl glycolide) (PSMG), Mn =361.8 kg/mol, Ð<1.30). Compared to previous catalysis systems, the side reactions were suppressed remarkably in this catalysis system because phenolic ester bond in monomer can be selectively cleaved over that in polymer chains during ROP progress. Mechanistic studies reveal that the halide anion and alkyl-quaternaryammonium cation work synergistically, where the alkyl-quaternaryammonium cation moiety interacts with the carbonyl group of substrates via non-classical hydrogen bonding. Moreover, these salicylic acid-based copolyesters can be recycled to dimeric monomer under solution condition, and can be recycled to original monomeric monomers without catalyst under sublimation condition.

Guanine Nucleotide-Binding Protein G(i) Subunit Alpha 2 Exacerbates NASH Progression by Regulating Peroxiredoxin 1-Related Inflammation and Lipophagy.

BACKGROUND AND AIMS: NASH is an advanced stage of liver disease accompanied by lipid accumulation, inflammation, and liver fibrosis. Guanine nucleotide-binding protein G(i) subunit alpha-2 (GNAI2) is a member of the "inhibitory" class of α-subunits, and recent studies showed that Gnai2 deficiency is known to cause reduced weight in mice. However, the role of GNAI2 in hepatocytes, particularly in the context of liver inflammation and lipid metabolism, remains to be elucidated. Herein, we aim to ascertain the function of GNAI2 in hepatocytes and its impact on the development of NASH. APPROACH AND RESULTS: Human liver tissues were obtained from NASH patients and healthy persons to evaluate the expression and clinical relevance of GNAI2. In addition, hepatocyte-specific Gnai2-deficient mice (Gnai2hep-/- ) were fed either a Western diet supplemented with fructose in drinking water (WDF) for 16 weeks or a methionine/choline-deficient diet (MCD) for 6 weeks to investigate the regulatory role and underlying mechanism of Gnai2 in NASH. GNAI2 was significantly up-regulated in liver tissues of patients with NASH. Following feeding with WDF or MCD diets, livers from Gnai2hep-/- mice had reduced steatohepatitis with suppression of markers of inflammation and an increase in lipophagy compared to Gnai2flox/flox mice. Toll-like receptor 4 signals through nuclear factor kappa B to trigger p65-dependent transcription of Gnai2. Intriguingly, immunoprecipitation, immunofluorescence, and mass spectrometry identified peroxiredoxin 1 (PRDX1) as a binding partner of GNAI2. Moreover, the function of PRDX1 in the suppression of TNF receptor-associated factor 6 ubiquitin-ligase activity and glycerophosphodiester phosphodiesterase domain-containing 5-related phosphatidylcholine metabolism was inhibited by GNAI2. Suppression of GNAI2 combined with overexpression of PRDX1 reversed the development of steatosis and fibrosis in vivo. CONCLUSIONS: GNAI2 is a major regulator that leads to the development of NASH. Thus, inhibition of GNAI2 could be an effective therapeutic target for the treatment of NASH.

Thermodynamic and sequential characteristics of phase separation and droplet formation for an intrinsically disordered region/protein ensemble.

Liquid-liquid phase separation (LLPS) of some IDPs/IDRs can lead to the formation of the membraneless organelles in vitro and in vivo, which are essential for many biological processes in the cell. Here we select three different IDR segments of chaperon Swc5 and develop a polymeric slab model at the residue-level. By performing the molecular dynamics simulations, LLPS can be observed at low temperatures even without charge interactions and disappear at high temperatures. Both the sequence length and the charge pattern of the Swc5 segments can influence the critical temperature of LLPS. The results suggest that the effects of the electrostatic interactions on the LLPS behaviors can change significantly with the ratios and distributions of the charged residues, especially the sequence charge decoration (SCD) values. In addition, three different forms of swc conformation can be distinguished on the phase diagram, which is different from the conventional behavior of the free IDP/IDR. Both the packed form (the condensed-phase) and the dispersed form (the dilute-phase) of swc chains are found to be coexisted when LLPS occurs. They change to the fully-spread form at high temperatures. These findings will be helpful for the investigation of the IDP/IDR ensemble behaviors as well as the fundamental mechanism of the LLPS process in bio-systems.

Epithelioid sarcoma: A clinicopathological study of 12 head and neck cases.

OBJECTIVES: To determine the clinicopathological features of epithelioid sarcoma presenting in head and neck region (HNES) and elucidate diagnostic key points and treatment options for HNES. MATERIALS AND METHODS: A total of 12 HNES cases were collected in our department from 2010 to 2020. Their clinical information and pathological features were documented, and relevant follow-up was performed. Immunohistochemistry was carried to analyze the protein markers of HNES. RESULTS: Of the 12 HNES cases, 10 were primary tumors and 2 were metastasized from foot and shoulder, respectively. The patients with primary tumors were significantly younger than those with metastasized ones (22.7 vs 41.5, p = .0157), and male patients outnumbered female patients (3:1). Of all HNES cases, 9 were classic subtype, and 3 were proximal subtype. HNES patients had a poor prognosis, with 5-year overall survival of 41.5% and 5-year relapse-free survival of 22.5%. A loss of INI1 was identified as the hallmark of HNES with 83.3% (10/12) of HNES cases presenting as EZH2 positive. CONCLUSIONS: HNES is more prevalent at younger ages and in males, has a poor prognosis, and exhibits a greater proportion of classic subtype than proximal subtype. EZH2 inhibitor has therapeutic potential in HNES.

Influence of sequence length and charged residues on Swc5 binding with histone H2A-H2B.

SWR is a member of chromatin remodeler family and participates the replacement of histone H2A with H2A.Z. One of the SWR subunits, Swc5, has an intrinsically disordered region and binds to H2A-H2B dimer. Though the binding structure of Swc5 and H2A-H2B has been resolved recently, it is still challenging to investigate the binding mechanism as well as the role of the charge interactions between Swc5 and H2A-H2B. Here we developed a coarse-grained structure-based model and performed molecular dynamics simulations to investigate the binding processes of two Swc5 regions with different lengths (swc5-a and swc5-b) to H2A-H2B. The simulation results suggest a different role of electrostatic interactions between swc5-a/swc5-b and H2A-H2B on binding. The electrostatic interactions between swc5-a/swc5-b and H2A-H2B can not only accelerate the initial capture step of binding, but can also trap the swc5-a/swc5-b at the wrong binding site on H2A. Besides, the conserved DEF/Y-2 motif of Swc5 is important for the binding affinity and the recognition with H2A-H2B at the initial step. Both swc5-a and swc5-b undergo a structural shift before reaching the final bound state. This theoretical study provides important details and the underlying physical mechanisms of the binding processes of swc5-a/swc5-b and H2A-H2B.

Physics of biomolecular recognition and conformational dynamics.

Biomolecular recognition usually leads to the formation of binding complexes, often accompanied by large-scale conformational changes. This process is fundamental to biological functions at the molecular and cellular levels. Uncovering the physical mechanisms of biomolecular recognition and quantifying the key biomolecular interactions are vital to understand these functions. The recently developed energy landscape theory has been successful in quantifying recognition processes and revealing the underlying mechanisms. Recent studies have shown that in addition to affinity, specificity is also crucial for biomolecular recognition. The proposed physical concept of intrinsic specificity based on the underlying energy landscape theory provides a practical way to quantify the specificity. Optimization of affinity and specificity can be adopted as a principle to guide the evolution and design of molecular recognition. This approach can also be used in practice for drug discovery using multidimensional screening to identify lead compounds. The energy landscape topography of molecular recognition is important for revealing the underlying flexible binding or binding-folding mechanisms. In this review, we first introduce the energy landscape theory for molecular recognition and then address four critical issues related to biomolecular recognition and conformational dynamics: (1) specificity quantification of molecular recognition; (2) evolution and design in molecular recognition; (3) flexible molecular recognition; (4) chromosome structural dynamics. The results described here and the discussions of the insights gained from the energy landscape topography can provide valuable guidance for further computational and experimental investigations of biomolecular recognition and conformational dynamics.

TRPC1/4/5 channels contribute to morphine-induced analgesic tolerance and hyperalgesia by enhancing spinal synaptic potentiation and structural plasticity.

Opioid analgesics remain the mainstay for managing intractable chronic pain, but their use is limited by detrimental side effects such as analgesic tolerance and hyperalgesia. Calcium-dependent synaptic plasticity is a key determinant in opiates tolerance and hyperalgesia. However, the exact substrates for this calcium-dependent synaptic plasticity in mediating these maladaptive processes are largely unknown. Canonical transient receptor potential 1, 4, and 5 (TRPC1, 4, 5) proteins assemble into heteromultimeric nonselective cation channels with high Ca2+ permeability and influence various neuronal functions. However, whether and how TRPC1/4/5 channels contribute to the development of opiates tolerance and hyperalgesia remains elusive. Here, we show that TRPC1/4/5 channels contribute to the generation of morphine tolerance and hyperalgesia. Chronic morphine exposure leads to upregulation of TRPC1/4/5 channels in the spinal cord. Spinally expressed TRPC1, TPRC4, and TRPC5 are required for chronic morphine-induced synaptic long-term potentiation (LTP) as well as remodeling of synaptic spines in the dorsal horn, thereby orchestrating functional and structural plasticity during the course of morphine-induced hyperalgesia and tolerance. These effects are attributed to TRPC1/4/5-mediated Ca2+ elevation in the spinal dorsal horn induced by chronic morphine treatment. This study identifies TRPC1/4/5 channels as a promising novel target to prevent the unwanted morphine tolerance and hyperalgesia.

Adverse Health Effects of Frailty: Systematic Review and Meta-Analysis of Middle-Aged and Older Adults With Implications for Evidence-Based Practice.

BACKGROUND: Scholars have noted that frailty easily leads to functional deterioration and proneness to complications. Little literature addresses the stages of frailty in middle-aged and older adults and the effects of frailty on overall health. AIMS: This study explores the effect of different stages of frailty on the prospective health (falls, bone fractures, disability, dementia, hospitalization, and death) of middle-aged and older adults. In addition, different frailty indicators were compared to determine their usefulness in predicting future adverse health outcomes. METHODS: The authors of this study separately reviewed and extracted data from the literature obtained while searching the following keywords: "frailty" OR "frail" and "fall" OR "disability" OR "fracture" OR "hospitalization" OR "mortality" OR "cognitive function" "dementia" OR "Alzheimer's disease" and "middle-aged people" OR "older people" OR "elderly" OR "geriatric" OR "senior." The literature search was performed from January 2001 to November 2019 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Specifically, we performed a systematic literature search in multiple databases-Embase, PubMed, MEDLINE, CINAHL, and Cochrane Library-and analyzed all obtained literature results using a random-effects model. RESULTS: We collected a total of 29 prospective studies for the systematic literature review and meta-analysis. The main results indicated that the frail groups had significantly higher risks of adverse health effects (falls, bone fractures, disability, dementia, hospitalization, and death) than the robust or prefrail groups. LINKING EVIDENCE TO ACTION: Frailty is a crucial healthcare topic among geriatric syndromes. Considering that older adults with frailty are most likely to develop severe adverse health outcomes, professional nursing personnel should assess frailty among middle-aged and older adults and offer relevant care strategies to reduce the adverse effects of frailty in this population.

GNAI1 and GNAI3 Reduce Colitis-Associated Tumorigenesis in Mice by Blocking IL6 Signaling and Down-regulating Expression of GNAI2.

BACKGROUND & AIMS: Interleukin 6 (IL6) and tumor necrosis factor contribute to the development of colitis-associated cancer (CAC). We investigated these signaling pathways and the involvement of G protein subunit alpha i1 (GNAI1), GNAI2, and GNAI3 in the development of CAC in mice and humans. METHODS: B6;129 wild-type (control) or mice with disruption of Gnai1, Gnai2, and/or Gnai3 or conditional disruption of Gnai2 in CD11c+ or epithelial cells were given dextran sulfate sodium (DSS) to induce colitis followed by azoxymethane (AOM) to induce carcinogenesis; some mice were given an antibody against IL6. Feces were collected from mice, and the compositions of microbiomes were analyzed by polymerase chain reactions. Dendritic cells (DCs) and myeloid-derived suppressor cells (MDSCs) isolated from spleen and colon tissues were analyzed by flow cytometry. We performed immunoprecipitation and immunoblot analyses of colon tumor tissues, MDSCs, and mouse embryonic fibroblasts to study the expression levels of GNAI1, GNAI2, and GNAI3 and the interactions of GNAI1 and GNAI3 with proteins in the IL6 signaling pathway. We analyzed the expression of Gnai2 messenger RNA by CD11c+ cells in the colonic lamina propria by PrimeFlow, expression of IL6 in DCs by flow cytometry, and secretion of cytokines in sera and colon tissues by enzyme-linked immunosorbent assay. We obtained colon tumor and matched nontumor tissues from 83 patients with colorectal cancer having surgery in China and 35 patients with CAC in the United States. Mouse and human colon tissues were analyzed by histology, immunoblot, immunohistochemistry, and/or RNA-sequencing analyses. RESULTS: GNAI1 and GNAI3 (GNAI1;3) double-knockout (DKO) mice developed more severe colitis after administration of DSS and significantly more colonic tumors than control mice after administration of AOM plus DSS. Development of increased tumors in DKO mice was not associated with changes in fecal microbiomes but was associated with activation of nuclear factor (NF) κB and signal transducer and activator of transcription (STAT) 3; increased levels of GNAI2, nitric oxide synthase 2, and IL6; increased numbers of CD4+ DCs and MDSCs; and decreased numbers of CD8+ DCs. IL6 was mainly produced by CD4+/CD11b+, but not CD8+, DCs in DKO mice. Injection of DKO mice with a blocking antibody against IL6 reduced the expansion of MDSCs and the number of tumors that developed after CAC induction. Incubation of MDSCs or mouse embryonic fibroblasts with IL6 induced activation of either NF-κB by a JAK2-TRAF6-TAK1-CHUK/IKKB signaling pathway or STAT3 by JAK2. This activation resulted in expression of GNAI2, IL6 signal transducer (IL6ST, also called GP130) and nitric oxide synthase 2, and expansion of MDSCs; the expression levels of these proteins and expansion of MDSCs were further increased by the absence of GNAI1;3 in cells and mice. Conditional disruption of Gnai2 in CD11c+ cells of DKO mice prevented activation of NF-κB and STAT3 and changes in numbers of DCs and MDSCs. Colon tumor tissues from patients with CAC had reduced levels of GNAI1 and GNAI3 and increased levels of GNAI2 compared with normal tissues. Further analysis of a public human colorectal tumor DNA microarray database (GSE39582) showed that low Gani1 and Gnai3 messenger RNA expression and high Gnai2 messenger RNA expression were significantly associated with decreased relapse-free survival. CONCLUSIONS: GNAI1;3 suppresses DSS-plus-AOM-induced colon tumor development in mice, whereas expression of GNAI2 in CD11c+ cells and IL6 in CD4+/CD11b+ DCs appears to promote these effects. Strategies to induce GNAI1;3, or block GNAI2 and IL6, might be developed for the prevention or therapy of CAC in patients.

Improving Broadband White-Light Emission Performances of 2D Perovskites by Subtly Regulating Organic Cations.

Recently, 2D organic-inorganic hybrid lead halide perovskites have attracted intensive attention in solid-state luminescence fields such as single-component white-light emitters, and rational optimization of the photoluminescence (PL) performance through accurate structural-design strategies is still significant. Herein, by carefully choosing homologous aliphatic amines as templates, isotypical perovskites [DMEDA]PbCl4 (1, DMEDA=N,N-dimethylethylenediamine) and [DMPDA]PbCl4 (2, DMPDA=N,N-dimethyl-1,3-diaminopropane) having tunable and stable broadband bluish white emission properties were rationally designed. The subtle regulation of organic cations leads to a higher degree of distortion of the 2D [PbCl4 ]2- layers and enhanced photoluminescence quantum efficiencies (<1 % for 1 and 4.9 % for 2). The broadband light emissions could be ascribed to self-trapped excitons on the basis of structural characterization, time-resolved PL, temperature-dependent PL emission, and theoretical calculations. This work gives a new guidance to rationally optimize the PL properties of low-dimensional halide perovskites and affords a platform to probe the structure-property relationship.