Discrete TrkB-expressing neurons of the dorsomedial hypothalamus regulate feeding and thermogenesis

Mutations in the TrkB neurotrophin receptor lead to profound obesity in humans, and expression of TrkB in the dorsomedial hypothalamus (DMH) is critical for maintaining energy homeostasis. However, the functional implications of TrkB-fexpressing neurons in the DMH (DMH^TrkB) on energy expenditure are unclear. Additionally, the neurocircuitry underlying the effect of DMH^TrkB neurons on energy homeostasis has not been explored. In this study, we show that activation of DMH^TrkB neurons leads to a robust increase in adaptive thermogenesis and energy expenditure without altering heart rate or blood pressure, while silencing DMH^TrkB neurons impairs thermogenesis. Furthermore, we reveal neuroanatomically and functionally distinct populations of DMH^TrkB neurons that regulate food intake or thermogenesis. Activation of DMH^TrkB neurons projecting to the raphe pallidus (RPa) stimulates thermogenesis and increased energy expenditure, whereas DMH^TrkB neurons that send collaterals to the paraventricular hypothalamus (PVH) and preoptic area (POA) inhibit feeding. Together, our findings provide evidence that DMH^TrkB neuronal activity plays an important role in regulating energy expenditure and delineate distinct neurocircuits that underly the separate effects of DMH^TrkB neuronal activity on food intake and thermogenesis.

Impairments in energy homeostasis resulting from the compound effects of overeating and sedentary lifestyles have led to a profound increase in the rate of obesity around the world (1). Therapeutic strategies aimed at combating obesity by increasing energy expenditure or decreasing appetite have commonly failed due to counterregulatory mechanisms (2) and adverse side effects on cardiovascular physiology (3–5). To achieve safe and sustained weight loss, it will be essential to understand the mechanisms that govern and coordinate discrete physiological processes that contribute to energy homeostasis.Adaptive thermogenesis is the process by which energy is converted into heat and occurs primarily in brown adipose tissue (BAT) in response to environmental cues (6). BAT has a particularly high capacity for dissipating energy from fat and thus represents an important component of energy homeostasis. The dorsomedial hypothalamus (DMH) in the brain is centrally positioned in an established thermoregulatory neurocircuit, receiving inputs from the preoptic area (POA) (7–9) and sending excitatory projections to preautonomic neurons in the raphe pallidus (RPa) (10–13) that promote sympathetic activity in BAT, leading to increased thermogenesis. Direct chemical stimulation of the DMH (14) or activation of select populations of thermogenic DMH neurons (9, 11, 12, 15) leads to increased body temperature and energy expenditure but also significantly increases heart rate and blood pressure (12, 13, 15, 16). An inability to target increased sympathetic tone specifically in BAT without affecting other target tissues has greatly hampered strategies to treat obesity by targeting thermogenesis (4, 5).In addition to its influence on energy expenditure, the DMH also represents an important brain region in the regulation of feeding (17–19). Lesioning studies support an orexigenic role for the DMH (17), which can promote food intake through inhibitory projections to either the paraventricular hypothalamus (PVH) (18) or the arcuate nucleus (ARC) (20). Despite these early findings, evidence has also emerged that demonstrates the importance of anorexigenic populations of DMH neurons (19, 21, 22). We previously established that the activity of DMH neurons expressing the neurotrophin receptor TrkB (DMH^TrkB) is important for regulating feeding, showing that activation of DMH^TrkB neurons suppresses feeding and that deletion of the TrkB-encoding Ntrk2 gene in the DMH results in hyperphagia and obesity (21). Furthermore, humans with mutations in the TrkB-encoding NTRK2 gene exhibit severe obesity and impaired thermoregulation (23). However, it is unclear whether activation of DMH^TrkB neurons has a direct influence on adaptive thermogenesis. Additionally, the neurocircuitry through which DMH^TrkB neurons govern feeding or energy expenditure is unknown.Here, we demonstrate that DMH^TrkB neuronal activity potently promotes energy expenditure by elevating thermogenesis and physical activity with a notable lack of influence on heart rate and blood pressure. We further reveal that DMH^TrkB neurons send diverging projections to the RPa or the POA and PVH to differentially regulate energy expenditure and food intake, respectively.     

Regulating kinetics and thermodynamics of electrochemical nitrogen reduction with metal single-atom catalysts in a pressurized electrolyser

Using renewable electricity to synthesize ammonia from nitrogen paves a sustainable route to making value-added chemicals but yet requires further advances in electrocatalyst development and device integration. By engineering both electrocatalyst and electrolyzer to simultaneously regulate chemical kinetics and thermodynamic driving forces of the electrocatalytic nitrogen reduction reaction (ENRR), we report herein stereoconfinement-induced densely populated metal single atoms (Rh, Ru, Co) on graphdiyne (GDY) matrix (formulated as M SA/GDY) and realized a boosted ENRR activity in a pressurized reaction system. Remarkably, under the pressurized environment, the hydrogen evolution reaction of M SA/GDY was effectively suppressed and the desired ENRR activity was strongly amplificated. As a result, the pressurized ENRR activity of Rh SA/GDY at 55 atm exhibited a record-high NH₃ formation rate of 74.15 μg h⁻¹⋅cm⁻², a Faraday efficiency of 20.36%, and a NH₃ partial current of 0.35 mA cm⁻² at −0.20 V versus reversible hydrogen electrode, which, respectively, displayed 7.3-, 4.9-, and 9.2-fold enhancements compared with those obtained under ambient conditions. Furthermore, a time-independent ammonia yield rate using purified ¹⁵N₂ confirmed the concrete ammonia electroproduction. Theoretical calculations reveal that the driving force for the formation of end-on N₂* on Rh SA/GDY increased by 9.62 kJ/mol under the pressurized conditions, facilitating the ENRR process. We envisage that the cooperative regulations of catalysts and electrochemical devices open up the possibilities for industrially viable electrochemical ammonia production.

Ammonia is essential for human propagation and thriving (1, 2). Today’s global ammonia production is excessively dependent on the Haber–Bosch method, which converts nitrogen and hydrogen to ammonia at high temperature (300–500 °C) and pressure (200–300 atm) (3). So far, this century-old strategy has contributed vastly annual productions, yet significantly exacerbating the global energy consumption and greenhouse-gas emission. Electrocatalytic N₂ reduction reaction (ENRR) to synthesize ammonia from nitrogen and water under mild conditions represents a viable alternative that strategically transforms the energy-intensive sector toward sustainability, while its efficiency achieved so far is fairly low (4–8).The primary hurdle obstructing the ENRR lies in issues such as the inherent inertness of N₂, the high-energy barrier of N₂ activation, multiple electron–proton transfers, the low solubility of N₂ in aqueous solutions and competing hydrogen evolution reaction (HER), etc. (9–12). On the basis of these premises, strategies are highlighted to modulate the kinetics and thermodynamic equilibrium of the progress, thus steering the reaction toward the production of ammonia while mitigating HER (13–16). From a kinetic perspective, many catalyst-centric approaches, such as introducing alloy, defects, doping, and strain, etc., have been explored to improve nitrogen reduction performance (17–21). The overall ENRR efficiency, however, is still insufficient to meet the practical requirements. On the other hand, the improvement of the thermodynamic driving force for ammonia production, such as regulating electrochemical reaction conditions, may offer equally positive effects to efficiently promote the N₂ reduction process and suppress the unwanted side reactions (22). Conventionally, exploration of the innovation of electrocatalysts or electrochemical cell devices has always been undergone independently, despite their indivisible interconnection nature. Indeed, the ENRR advancements toward the envisioned practical applications depend very much on the cooperative development of both electrocatalysts and electrochemical cell devices (23).Given that the reductive N₂ adsorption (N₂ + e⁻ + H⁺ → *N = NH) is usually regarded as the potential limiting step, novel metal single-atom catalysts (SACs, e.g., Ru, Rh, Co) with a favorable ENRR kinetics guarantee a great promise to circumvent the N₂ activation energy barrier (24–27). These catalysts, on the other hand, also suffer vigorous competition from HER and low content of metal loading (28–30). Encouragingly, the most recent research work demonstrated that the system-level regulation of the pressurized electrocatalytic environment could affect the chemical equilibrium of the ammonia production reaction and meanwhile endow tangible HER suppression (31). It thus warrants research efforts to query whether the integration of SACs with pressurized electrochemical environments will lever synergies between kinetics and thermodynamic driving forces and be the game-changer for the ENRR.Herein, we showcase that SACs-catalyzed N₂ reduction in a pressurized system is an effective design principle to enhance both the chemical kinetics and thermodynamic process, leading to the amplified ENRR activity with simultaneously retarded HER. The deployed SACs contain Ru, Rh, and Co atoms featured with densely populated active sites and stabilized on graphdiyne (GDY) support (referred to as M SA/GDY; M = Rh, Ru, and Co); these electrocatalysts were prepared by a facile and mild method via stereoconfinement of metal atoms on the GDY framework. Through extensive ENRR test using adequately cleaned N₂, we found that the as-prepared M SA/GDY electrocatalysts render prominently enhanced ammonia electroproduction with obvious HER inhibition at the pressurized electrocatalytic system, suggesting positive cooperation between SAC and the pressurized environment. Remarkably, a record-high ammonia yield rate of 74.15 μg h⁻¹⋅cm⁻², a Faraday efficiency (FE) of 20.36%, and a NH₃ partial current density of 0.35 mA cm⁻² were achieved for Rh SA/GDY at 55 atm of N₂, which shows 7.3-, 4.9-, and 9.2-fold enhancement in comparison with those obtained in ambient conditions, outperforming the state-of-art ENRR catalysts. Additionally, a time-independent ammonia yield rate using adequately cleaned ¹⁵N₂ ensured the ammonia electrosynthesis from N₂.     

Helicobacter pylori specific immune response induced by conservative flagellin linear B-cell epitope

AIM:To testify the immunogenicity of a conservative B-cell linear epitope of Helicobacter pylori (H pylori) flagellin A. METHODS: Different programs were used to analyze the secondary structure, molecular hydropathy, and surface accessibility of H pylori flagellin A. Linear B-cell epitopes were estimated based on the structural and physiochemical information. Analysis of residue divergence was proposed to screen a conservative linear epitope. The 29-peptide (Pep29mer) synthesized by chemical method, including the predicted conservative B-cell epitope and a known K2d compatible T-cell epitope, was used to immunize mice, and then H pylori-specific antibodies were detected by ELISA. RESULTS: Based on the analyses of divergent amino acid residues, structural and physiochemical characteristics, it was strongly suggested that the short fragment NDSDGR was the core of a conservative linear epitope in flagellin A. Animals immunized by Pep29mer acquired efficient immune response. In detail, serum H pylori-specific IgA and IgGl increased significantly in immunized group, while IgG2a only had an insignificant change. H pylori-specific IgA in gastrointestinal flushing fluid also increased significantly. CONCLUSION: The conservative short fragment NDSDGR is the core of a linear B-cell epitope of flagellin A.     

螺内酯对肝硬变门脉血流动力学的实验和临床研究

目的探索螺内酯对门脉高压实验犬和肝硬变患者门脉血流动力学的作用．方法用直接门脉插管测压和９９ｍＴｃＭＩＢＩ心肝放射性摄取比值（Ｈ／Ｌ）测定慢性胆总管结扎肝硬变犬（ｎ＝１６）门静脉压力和门体分流，口服螺内酯２０ｍｇ／（ｋｇ·ｄ）．肝硬变患者１４例测定Ｈ／Ｌ，门静脉内径和流速后口服螺内酯８０ｍｇ／ｄ，４ｗｋ为１疗程．结果完成试验的犬１３只治疗前后门脉压力（ｋＰａ）从２５９±０５１下降为２４２±０４７（Ｐ＜００５），Ｈ／Ｌ从０３３±００６降至０３０±００８（Ｐ＜００５）．１４例肝硬变患者治疗前后Ｈ／Ｌ值从１２０±０２６降为１０２±０３４（Ｐ＜００５），门脉内径（ｍｍ）从１３９±２３缩小为１２３±２０（Ｐ＜００５）．门静脉流速明显增加．结论螺内酯口服可降低门脉压力和门体分流．     

APPL1 acts as a protective factor against podocytes injury in high glucose environment

APPL1, an intracellular adaptor protein, takes part in numerous metabolic reactions. Although APPL1 plays a key role in glucose metabolism via adiponectin pathway and has been proved associated with type 2 diabetes, little is known about its role in diabetic nephropathy. To explore the role of APPL1 in diabetic nephropathy, we upregulated the expression of APPL1 in cultured mouse podocytes by adenovirus infection and tested the effects of APPL1 overexpression in podocytes treated with high glucose. Here, a mouse podocyte cell line (generated from H-2Kb-tsA58 immortmouse) was cultured and divided into four groups: Group 1 (normal glucose, NG), Group 2 (high glucose, HG), Group 3 (HG and infected with control adenovirus) and Group 4 (HG and infected with Ad-APPL1). Cell vitality of Group 4 is significantly higher than Group 2, but notably lower than Group 1 (P<0.01). The apoptosis rate of Group 4 was much lower (P<0.01) than Group 2 and Group 3. A decrease in phase G0/G1 and an increase in phase S was observed in Group 4 compared with Group 2 (P<0.01). These data suggested the protective role of APPL1 overexpression in high glucose condition. Moreover, the levels of Nephrin, AMPK and p-AMPK were decreased by high-glucose treatment, but increased by APPL1 overexpression. In conclusion, in the experimental high glucose condition, APPL1 acts as a protective factor against podocytes injury through regulating AMPK signaling, and may be a new therapy target for diabetic nephropathy.     

Human Rhinovirus-induced Proinflammatory Cytokine and Interferon-β Responses in Nasal Epithelial Cells From Chronic Rhinosinusitis Patients

Purpose

Asthma exacerbation from human rhinovirus (HRV) infection is associated with deficient antiviral interferon (IFN) secretion. Although chronic rhinosinusitis (CRS), an inflammatory upper airway disease, is closely linked to asthma, IFN-β responses to HRV infections in human nasal epithelial cells (HNECs) from CRS patients remain to be studied. We evaluated inflammatory and antiviral responses to HRV infection in HNECs from CRS patients.

Methods

HNECs, isolated from turbinate tissue of 13 patients with CRS and 14 non-CRS controls, were infected with HRV16 for 4 hours. The HRV titer, LDH activity, production of proinflammatory cytokines and IFN-β proteins, and expression levels of RIG-I and MDA5 mRNA were assessed at 8, 24, and 48 hours after HRV16 infection.

Results

The reduction in viral titer was slightly delayed in the CRS group compared to the non-CRS control group. IL-6 and IL-8 were significantly increased to a similar extent in both groups after HRV infection. In the control group, IFN-β production and MDA5 mRNA expression were significantly increased at 8 and 24 hours after HRV16 infection, respectively. By contrast, in the CRS group, IFN-β was not induced by HRV infection; however, HRV-induced MDA5 mRNA expression was increased, but the increase was slightly delayed compared to the non-CRS control group. The RIG-I mRNA level was not significantly increased by HRV16 infection in either group.

Conclusions

HRV-induced secretion of proinflammatory cytokines in CRS patients was not different from that in the non-CRS controls. However, reductions in viral titer, IFN-β secretion, and MDA5 mRNA expression in response to HRV infection in CRS patients were slightly impaired compared to those in the controls, suggesting that HRV clearance in CRS patients might be slightly deficient.     

Expression of Tim-3 in gastric cancer tissue and its relationship with prognosis

As a negative regulatory molecule, T-cell immunoglobulin–and mucin domain-3 (Tim-3) plays a crucial role in the tumor immunological tolerance. In the present study, we aimed to determine the Tim-3 expression in gastric cancer tissue and its relationship with clinicopathological parameters and prognosis. The Tim-3 expression was assessed in 52 gastric cancer specimens and 15 gastritis tissues by flow cytometry, and gastritis tissues served as the control. As a result, we found that the Tim-3 expressions on CD4⁺T cells and CD8⁺T cells in gastric cancer tissue was significantly higher than those in gastritis tissue (P=0.022, P=0.047, respectively). The median expression level of Tim-3 on CD4⁺T cells were significantly correlated with clinicopathological parameters, such as tumor size, lymph node metastasis, the depth of tumor invasion and TNM staging (P=0.042, P=0.026, P=0.001, P=0.003, respectively), while it was not correlated with sex, age and histological subtype (all P>0.05). In CD8⁺T cells, the Tim-3 expression was relevant to tumor invasion and TNM staging (P=0.035, P=0.017, respectively), while it was irrelevant to other clinicopathological parameters (all P>0.05). Additionally, Kaplan-Meier survival curves showed that the median overall survival time of patients with lower Tim-3 expression was greater than that of patients with higher Tim-3 expression in CD4⁺T cells and CD8⁺T cells (χ²=18.036, P<0.001 and χ²=18.036, P<0.001, respectively). Moreover, the multivariate analysis revealed that the Tim-3 expression and TNM stage were independent prognostic factors for gastric cancer patients (P=0.029, P=0.043 and P=0.003, respectively). These results suggest that Tim-3 played an important role in the development and progression of gastric cancer, and it could be used as an independent prognostic factor for gastric cancer patients.     

Increased expression of 78 kD glucose-regulated protein promotes cardiomyocyte apoptosis in a rat model of liver cirrhosis

Aims: This study was to investigate the role and underlying mechanism of 78 kD glucose-regulated protein (GRP78) in cardiomyocyte apoptosis in a rat model of liver cirrhosis. Methods: A rat model of liver cirrhosis was established with multiple pathogenic factors. A total of 42 male SD rats were randomly divided into the liver cirrhosis group and control group. Cardiac structure analysis was performed to assess alterations in cardiac structure. Cardiomyocytes apoptosis was detected by TdT-mediated dUTP nick end labeling method. Expression of GRP78, CCAAT/enhancer-binding protein homologous protein (CHOP), caspase-12, nuclear factor kappa-light-chain-enhancer of activated B cells p65 subunit (NF-κB p65) and B cell lymphoma-2 (Bcl-2) was detected by immunohistochemical staining. Results: The ratios of left ventricular wall thickness to heart weight and heart weight to body weight were significantly increased with the progression of liver cirrhosis (P < 0.05). Apoptosis index of cardiomyocytes was significantly increased with the progression of liver cirrhosis (P < 0.05). The expression levels of GRP78, CHOP and caspase-12 were significantly increased in the progression of liver cirrhosis (P < 0.05). The expression levels of NF-κB p65 and Bcl-2 were highest in the 4-wk liver cirrhosis, and they were decreased in the 6-wk and 8-wk in the progression of liver cirrhosis. GRP78 expression levels were positively correlated with apoptosis index, CHOP and caspase-12 expression levels (P < 0.05). CHOP expression levels were negatively correlated with NF-κB p65 and Bcl-2 expression levels (P < 0.05). Conclusion: Increased expression of GRP78 promotes cardiomyocyte apoptosis in rats with cirrhotic cardiomyopathy.     

Inhibition of SALL4 suppresses carcinogenesis of colorectal cancer via regulating Gli1 expression

Background: SALL4 is a novel oncogene mediating tumorigenesis in multiple carcinomas. However, its actual role and mechanisms participating in the development of colorectal cancer remains unclear. Methods: Immunohistochemical staining and Western blot were conducted to detect the expression of SALL4 and other molecules. siRNA of SALL4 was transfected to silence SALL4 expression in Caco-2 cell line. Flow cytometry was used for cell cycle and apoptosis analysis. Wound healing and transwell assay were used for invasion test. CCK-8 test was employed for cell proliferation and drug sensitivity assessment. Results: By inhibition of SALL4 expression, the proliferation, invasiveness and drug resistance were dramatically reduced while apoptosis rate was up-regulated. Gli1 was found to decrease its expression in SALL4 silencing cells. Moreover, the inhibition on tumorigenesis of Caco-2 by SALL4 silencing was antagonized by Gli1 up-regulation, suggesting Gli1 as a downstream target of SALL4 in cancer development. Conclusion: SALL4 inhibition limited oncogenesis on colorectal cancer by reducing Gli1 expression.