TOR-mediated Ypt1 phosphorylation regulates autophagy initiation complex assembly.

The regulation of autophagy initiation is a key step in autophagosome biogenesis. However, our understanding of the molecular mechanisms underlying the stepwise assembly of ATG proteins during this process remains incomplete. The Rab GTPase Ypt1/Rab1 is recognized as an essential autophagy regulator. Here, we identify Atg23 and Atg17 as binding partners of Ypt1, with their direct interaction proving crucial for the stepwise assembly of autophagy initiation complexes. Disruption of Ypt1-Atg23 binding results in significantly reduced Atg9 interactions with Atg11, Atg13, and Atg17, thus preventing the recruitment of Atg9 vesicles to the phagophore assembly site (PAS). Likewise, Ypt1-Atg17 binding contributes to the PAS recruitment of Ypt1 and Atg1. Importantly, we found that Ypt1 is phosphorylated by TOR at the Ser174 residue. Converting this residue to alanine blocks Ypt1 phosphorylation by TOR and enhances autophagy. Conversely, the Ypt1S174D phosphorylation mimic impairs both PAS recruitment and activation of Atg1, thus inhibiting subsequent autophagy. Thus, we propose TOR-mediated Ypt1 as a multifunctional assembly factor that controls autophagy initiation via its regulation of the stepwise assembly of ATG proteins.

Mec1 regulates PAS recruitment of Atg13 via direct binding with Atg13 during glucose starvation-induced autophagy.

Mec1 is a DNA damage sensor, which performs an essential role in the DNA damage response pathway and glucose starvation-induced autophagy. However, the functions of Mec1 in autophagy remain unclear. In response to glucose starvation, Mec1 forms puncta, which are recruited to mitochondria through the adaptor protein Ggc1. Here, we show that Mec1 puncta also contact the phagophore assembly site (PAS) via direct binding with Atg13. Functional analysis of the Atg13-Mec1 interaction revealed two previously unrecognized protein regions, the Mec1-Binding Region (MBR) on Atg13 and the Atg13-Binding Region (ABR) on Mec1, which mediate their mutual association under glucose starvation conditions. Disruption of the MBR or ABR impairs the recruitment of Mec1 puncta and Atg13 to the PAS, consequently blocking glucose starvation-induced autophagy. Additionally, the MBR and ABR regions are also crucial for DNA damage-induced autophagy. We thus propose that Mec1 regulates glucose starvation-induced autophagy by controlling Atg13 recruitment to the PAS.

Upregulation of p300 in paclitaxel-resistant TNBC: implications for cell proliferation via the PCK1/AMPK axis.

OBJECTIVE: To explore the role of p300 in the context of paclitaxel (PTX) resistance in triple-negative breast cancer (TNBC) cells, focusing on its interaction with the phosphoenolpyruvate carboxykinase 1 (PCK1)/adenosine monophosphate-activated protein kinase (AMPK) pathway. METHODS: The expression of p300 and PCK1 at the messenger ribonucleic acid (mRNA) level was detected using a quantitative polymerase chain reaction. The GeneCards and GEPIA databases were used to investigate the relationship between p300 and PCK1. The MDA-MB-231/PTX cell line, known for its PTX resistance, was chosen to understand the specific role of p300 in such cells. The Lipofectamine™ 3000 reagent was used to transfer the p300 small interfering RNA and the overexpression of PCK1 plasmid into MDA-MB-231/PTX. The expression levels of p300, PCK1, 5'AMPK and phosphorylated AMPK (p-AMPK) were determined using the western blot test. RESULTS: In TNBC cancer tissue, the expression of p300 was increased compared with TNBC paracancerous tissue (P < 0.05). In the MDA-MB-231 cell line of TNBC, the expression of p300 was lower than in the PTX-resistant TNBC cells (MDA-MB-231/PTX) (P < 0.05). The PCK1 expression was decreased in the TNBC cancer tissue compared with TNBC paracancerous tissue, and the PCK1 expression was reduced in MDA-MB-231/PTX than in MDA-MB-231 (P < 0.05) indicating that PCK1 was involved in the resistance function. Additionally, p-AMPK was decreased in MDA-MB-231/PTX compared with MDA-MB-231 (P < 0.05). The adenosine triphosphate (ATP) level was also detected and was significantly lower in MDA-MB-231/PTX than in MDA-MB-231 (P < 0.05). Additionally, cell proliferation increased significantly in MDA-MB-231/PTX at 48 and 72 h (P < 0.05) suggesting that MDA-MB-231/PTX cells obtained the resistance function which was associated with AMPK and ATP level. When p300 was inhibited, p-AMPK and ATP levels elevated in MDA-MB-231/PTX (P < 0.05). When PCK1 was suppressed, the ATP consumption rate decreased, and cell proliferation increased (P < 0.05). However, there were no changes in p300. CONCLUSIONS: In MDA-MB-231/PTX, p300 can inhibit p-AMPK and ATP levels by inhibiting PCK1 expression. Our findings suggest that targeting p300 could modulate the PCK1/AMPK axis, offering a potential therapeutic avenue for overcoming PTX resistance in TNBC.

Collagen study advances for photoaging skin.

BACKGROUND: Collagen dominates the skin's extracellular matrix (ECM). Type I collagen comprises 80%-90% of the skin's collagen, followed by type III (8%-12%) and type V (5%). Reactive oxygen species, matrix metalloproteinases, and collagen degradation all increase during photoaging, which disrupts the ECM's dynamic balance and lowers the amount of total collagen in the body. In recent years, domestic and foreign researchers have conducted multidimensional and multifaceted studies on collagen and skin photoaging. Collagen and the peptides that are derivates of it are currently being used more and more in biomedicine and medical esthetics. OBJECTIVE: Offering new suggestions for both the avoidance and remedy of photoaging. METHODS: This article reviews collagen and its potential connection to skin photoaging, illustrates the effects of collagen and peptide supplementation derivatives on photoaged skin, and briefly describes other compounds that can also be used to fight photoaging by increasing collagen synthesis in the skin. RESULT: Both internal and external aging are inevitable, and as the main component of extracellular matrix, collagen plays a variety of functions in maintaining skin structure and fighting skin aging, and its role in photoaging is undeniable. Ultraviolet radiation can induce increased fragmentation and degradation of cutaneous collagen, while conversely, supplementation with collagen can effectively counteract photodamage-induced skin impairment. CONCLUSION: Collagen and its derived peptides are indispensable in photoaging skin, holding promising prospects for applications in skin aging.

Synergistic mitigation of cadmium stress in rice (Oryza sativa L.) through combined selenium, calcium, and magnesium supplementation.

Rice is susceptible to cadmium (Cd) accumulation, which poses a threat to human health. Traditional methods for mitigating moderately contaminated soils can be impractical or prohibitively expensive, necessitating innovative approaches to reduce Cd uptake in rice. Nutrient management has emerged as a promising solution by leveraging the antagonistic interactions between nutrients and cadmium. However, the research on the synergistic effects of multiple nutrients on Cd toxicity in rice is limited. To address this limitation, pot experiments was utilized to investigate the combined effects of selenium (Se), calcium (Ca), and magnesium (Mg) denoted as (SeCM) on Cd uptake and translocation in rice. The synergistic application of SeCM reduced grain Cd levels by 55.0%, surpassing the individual effects of Se (42.1%) and CM (40.5%), and bringing Cd content below the safe consumption limits. SeCM treatment exhibited multiple beneficial effects: it decreased malondialdehyde (MDA) levels, enhanced catalase (CAT), peroxidase (POD) and glutathione (GSH) enzyme activities, limited Cd translocation from roots to shoots, promoted iron plaque formation, and reduced Cd transfer from soil to iron plaque and subsequently to rice grains. Correlation analysis revealed strong negative relationships between rice Cd content, Cd translocation factors, and the translocation factors of selenium, calcium, and magnesium. These findings suggest that selenium, calcium, and magnesium collaboratively mitigate Cd toxicity through antagonistic and competitive interactions. These nutrients enhance the uptake of beneficial elements, while competitively inhibiting the translocation and accumulation of Cd in rice plants. SeCM application offers a promising strategy for producing nutrient-rich, and Cd-safe rice in contaminated soils.

Stabilization of Dinuclear Rhodium and Iridium Clusters on Layered Titanate and Niobate Supports.

Atomically dispersed organometallic clusters can provide well-defined nuclearity of active sites for both fundamental studies as well as new regimes of activity and selectivity in chemical transformations. More recently, dinuclear clusters adsorbed onto solid surfaces have shown novel catalytic properties resulting from the synergistic effect of two metal centers to anchor different reactant species. Difficulty in synthesizing, stabilizing, and characterizing isolated atoms and clusters without agglomeration challenges allocating catalytic performance to atomic structure. Here, we explore the stability of dinuclear rhodium and iridium clusters adsorbed onto layered titanate and niobate supports using molecular precursors. Both systems maintain their nuclearity when characterized using aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Statistical analysis of HAADF-STEM images revealed that rhodium and iridium dimers had mean cluster-to-cluster distances very similar to what is expected from a random distribution of atoms over a large area, indicating that they are dispersed without aggregation. The stability of dinuclear rhodium clusters supported on titanate nanosheets was also investigated by X-ray absorption fine structure (EXAFS), DRIFTS, and first-principles calculations. Both X-ray absorption spectroscopy and HAADF-STEM simulations, guided by density functional theory (DFT)-optimized structure models, suggested that rhodium dimers adsorb onto the nanosheets in an end-on binding mode that is stable up to 100 °C under reducing conditions. This study highlights that crystalline nanosheets derived from layered metal oxides can be used as model supports to selectively stabilize dinuclear clusters, which could have implications for heterogeneous catalysis.

Molecular detection and phylogenetic analysis of pigeon circovirus from racing pigeons in Northern China.

BACKGROUND: Pigeon circovirus (PiCV) infections in pigeons (Columba livia) have been reported worldwide. Currently, pigeon racing is becoming increasingly popular and considered to be a national sport in China, and even, the greatest competitions of racing pigeons are taking place in China. However, there are still no epidemiologic data regarding PiCV infections among racing pigeons in China. The purpose of our study was to provide information of prevalence, genetic variation and evolution of PiCV from racing pigeons in China. RESULTS: To trace the prevalence, genetic variation and evolution of PiCV in sick and healthy racing pigeons, 622 samples were collected from 11 provinces or municipalities in China from 2016 to 2019. The results showed that the positive rate of PiCV was 19.3% (120/622) at the sample level and 59.0% (23/39) at the club level, thus suggesting that the virus was prevalent in Chinese racing pigeons. A sequence analysis revealed that the cap genes of the PiCV strains identified in our study displayed a high genetic diversity and shared nucleotide homologies of 71.9%-100% and amino acid homologies of 71.7%-100%. 28 and 36 unique amino acid substitutions were observed in the Cap and Rep proteins derived from our PiCV strains, respectively. A cladogram representation of PiCV strains phylogeny based on 90 cap gene sequences showed that the strains in this study could be further divided into seven clades (A, B, C, E, G, H, and I) and some of them were closely related to worldwide strains from different types of pigeons. A large number of recombination events (31 events) were also detected in the PiCV genomes from Chinese racing pigeons. CONCLUSIONS: These findings indicate that PiCV strains circulating in China exhibit a high genetic diversity and also contribute to information of prevalence, genetic variation and evolution of PiCV from racing pigeons in China.

Human α-defensin 5 suppressed colon cancer growth by targeting PI3K pathway.

Defensins are highly conserved antimicrobial peptides, which ubiquitously expressed in different species. In addition to the functions in host defense, their aberrant expression have also been documented in cancerous tissue including breast cancer, lung caner and renal carcinoma etc. Whereas, roles of Defensin Alpha 5 (DEFA5) in colon cancer has not been explored. Bioinformatic analysis was used to study the expression of DEFA5 and its correlation with clinical outcomes; Western blot, qPCR, Co-immunoprecipitation, xenograft models were used to the study the molecular mechanism. Decreased expression of DEFA5 at protein level was observed in colon tissues. Colon cancer cell lines proliferation and colony formation capacity were significantly suppressed by DEFA5 overexpression. Moreover, in vivo tumor growth in nude mice was also suppressed by DEFA5 overexpression, suggesting a tumor suppressor role of DEFA5 in colon cancer. Mechanistically, DEFA5 directly binds to the subunits of PI3K complex, thus attenuates the downstream signaling transduction, leads to delayed cell growth and metastasis. Collectively, we concluded that DEFA5 showed an inhibitory effect in colon cancer cell growth and may serve as a potential tumor suppressor in colon cancer.

Expression of the human or porcine C-type lectins DC-SIGN/L-SIGN confers susceptibility to porcine epidemic diarrhea virus entry and infection in otherwise refractory cell lines.

Porcine epidemic diarrhea virus (PEDV) is an alphacoronavirus that causes great economic losses in the porcine industry. Although the functional receptor for the virus has not been identified, multiple isolates are able to infect different cell lines. Recently, it has been shown that the human C-type lectin DC-SIGN/L-SIGN (hDC-SIGN/L-SIGN) can promote entry of several coronaviruses. Here we examined whether hDC-SIGN/L-SIGN and its porcine homolog (pDC-SIGN) are entry determinants for PEDV. Expression of hDC-SIGN/L-SIGN or pDC-SIGN in refractory cells dramatically increased infection by a recombinant PEDV expressing green fluorescent protein. In both cases, lectin-mediated infection was inhibited by mannan or anti-hDC-SIGN/L-SIGN or pDC-SIGN antibodies; however, d-galactose had no effect on the virus-infected cells. Our results demonstrate that hDC-SIGN/L-SIGN or pDC-SIGN can mediate the cellular entry and propagation of PEDV, which provides a new theoretical basis for further understanding the infection mechanism of PEDV, and will be helpful for the development of novel therapeutic agents.

Bromo- and extraterminal domain protein inhibition improves immunotherapy efficacy in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) represents the majority of liver cancer and is the fourth most common cause of cancer-related death. Although advances in molecular targeted therapy have shown promise, none of these agents has yet demonstrated significant clinical benefit. Bromo- and extraterminal domain (BET) protein inhibitors have been considered potential therapeutic drugs for HCC but the biological activity remains unclear. This study found that BET protein inhibition did not effectively suppress the progression of HCC, using a transgenic HCC mouse model. Mechanistically, the BET protein inhibitor JQ1 upregulated the expression of programmed cell death-ligand 1 (PD-L1) on the plasma membrane in vivo and in vitro. Moreover, JQ1 enhanced the expression of Rab8A, which upregulated the expression of PD-L1 on the plasma membrane. This study also showed that JQ1 combined with anti-PD-L1 Ab effectively suppressed HCC progression, and this benefit was obtained by enhancing the activation and cytotoxic capabilities of CD8 T cells. These results revealed the crucial role and regulation of BET protein inhibition on the expression of PD-L1 in HCC. Thus, combining BET protein inhibition with immune checkpoint blockade offers an efficient therapeutic approach for HCC.

The role of autophagy in maintaining intestinal mucosal barrier.

The intestinal mucosal barrier is the first line to defense against luminal content penetration and performs numerous biological functions. The intestinal epithelium contains a huge surface that is lined by a monolayer of intestinal epithelial cells (IECs). IECs are dominant mediators in maintaining intestinal homeostasis that drive diverse functions including nutrient absorption, physical segregation, secretion of antibacterial peptides, and modulation of immune responses. Autophagy is a cellular self-protection mechanism in response to various stresses, and accumulating studies have revealed its importance in participating physiological processes of IECs. The regulatory effects of autophagy depend on the specific IEC types. This review aims to elucidate the myriad roles of autophagy in regulating the functions of different IECs (stem cells, enterocytes, goblet cells, and Paneth cells), and present the progress of autophagy-targeting therapy in intestinal diseases. Understanding the involved mechanisms can provide new preventive and therapeutic strategies for gastrointestinal dysfunction and diseases.

Porcine Deltacoronavirus Engages the Transmissible Gastroenteritis Virus Functional Receptor Porcine Aminopeptidase N for Infectious Cellular Entry.

Identification of cellular receptors used by coronavirus (CoV) entry into the host cells is critical to an understanding of pathogenesis and to development of intervention strategies. The fourth CoV genus, Deltacoronavirus, evolutionarily related to the Gammacoronavirus, has just been defined recently. In the current study, we demonstrate that porcine aminopeptidase N (pAPN) acts as a cross-genus CoV functional receptor for both enteropathogenic porcine deltacoronovirus (PDCoV) and alphacoronovirus (AlphaCoV) (transmissible gastroenteritis virus [TGEV]) based upon three lines of evidence. First, the soluble S1 protein of PDCoV bound to the surface of target porcine cell lines known to express pAPN as efficiently as TGEV-S1, which could be blocked by soluble pAPN pretreatment. Second, both PDCoV-S1 and TGEV-S1 physically recognized and interacted with pAPN by coimmunoprecipitation in pAPN cDNA-transfected cells and by dot blot hybridization assay. Finally, exogenous expression of pAPN in refractory cells conferred susceptibility to PDCoV-S1 binding and to PDCoV entry and productive infection. PDCoV-S1 appeared to have a lower pAPN-binding affinity and likely consequent lower infection efficiency in pAPN-expressing refractory cells than TGEV-S1, suggesting that there may be differences between these two viruses in the virus-binding regions in pAPN. This study paves the way for dissecting the molecular mechanisms of PDCoV-host interactions and pathogenesis as well as facilitates future vaccine development and intervention strategies against PDCoV infection.IMPORTANCE The emergence of new human and animal coronaviruses is believed to have occurred through interspecies transmission that is mainly mediated by a species-specific receptor of the host. Among the four genera of the Coronavirinae, a couple of functional receptors for the representative members in the genera Alphacoronavirus and Betacoronavirus have been identified, whereas receptors for Gammacoronavirus and Deltacoronavirus, which are believed to originate from birds, are still unknown. Porcine coronaviruses, including the newly discovered porcine deltacoronavirus (PDCoV) associated with diarrhea in newborn piglets, have posed a serious threat to the pork industry in Asia and North America. Here, we report that PDCoV employs the alphacoronavirus TGEV functional receptor porcine aminopeptidase N (pAPN) for cellular entry, demonstrating the usage of pAPN as a cross-genus CoV functional receptor. The identification of the PDCoV receptor provides another example of the expanded host range of CoV and paves the way for further investigation of PDCoV-host interaction and pathogenesis.

Effects of Tumor Necrosis Factor α (TNF-α) and Interleukina 10 (IL-10) on Intercellular Cell Adhesion Molecule-1 (ICAM-1) and Cluster of Differentiation 31 (CD31) in Human Coronary Artery Endothelial Cells.

BACKGROUND The aim of this study was to investigate the effects of TNF-α and IL-10 on the expression of ICAM-1 and CD31 in human coronary artery endothelial cells (HCAEC). MATERIAL AND METHODS HCAEC was treated with 0, 2.5 µg/l, 5 µg/l, and 10 µg/l of TNF-α for 2 h, 6 h, and 10 h, and with 0 µg/l, 10 µg/l, 100 µg/l, and 200 µg/l of IL-10 for 5 h, 10 h and 15 h, respectively. RNA inference of TNF-αR was performed with siRNA. Real-time PCR, Western blot analysis, and ELSA were used to detect the mRNA level and protein level of ICAM-1 and CD31. RESULTS TNF-α significantly increased the mRNA and protein expression of ICAM-1 (P<0.05), and 2.5 µg/l TNF-α had the most obvious effect. RNAi of TNF-aR reduced the induction of TNF-α on the mRNA and protein expression of ICAM-1 (P<0.05). TNF-α significantly decreased the CD31 in the supernatant (P<0.05), and 2.5 µg/l TNF-a had the most obvious effect. IL-10 significantly decreased the ICAM-1 protein level. IL-10 decreased the mRNA expression and the protein expression of CD31. The effect on mRNA was not significant (P>0.05), while the effect on the protein expression was significant (P<0.05). CONCLUSIONS TNF-α and IL-10 treatment can affect the expression of ICAM-1 and CD31 in HCAEC.

[Effect of Cynomorium songaricum polysaccharide on telomere of lung cancer A549 cells].

To study the effect of Cynomorium songaricum polysaccharide (CSRP) on A549 cells telomere of human non-small cell lung cancer, the mice were intragastric administrated with CSRP (0.08 g•kg⁻¹) once daily for 4 days. Then their serum was taken for preparing CSRP drug serum. A549 cells were treated by the drug serum, and the effect of drug serum with different concentrations and different treating time on the proliferation of non-small cell lung cancer A549 cells was determined by MTT test. After treating for 48 hours by the drug serum of different concentrations, the telomere length of the cells was determined by fluorescence quantitative polymerase chain reaction (qPCR); the mRNA expression of telomerase reverse transcriptase (TERT) was determined by RT-qPCR; the cells apoptosis was determined by TUNEL assay. The results demonstrated that CSRP of various concentrations could inhibit the proliferation of the lung cancer A549 cells significantly, and the inhibition effect was strongest at 48 hours with the concentration of 6.0 mL•L⁻¹. At 48 h, that CSRP of the concentrations from 1.5 to 12.0 mL•L⁻¹ could significantly shorten the telomere length of A549 cells, and the effect was strongest with the concentration of 1.5 mg•L⁻¹. CSRP of various concentrations could significantly inhibit the mRNA expression of TERT in A549 cells, and the inhibition effect was stronger when the concentration was ≥6.0 mL•L⁻¹. CSRP of various concentrations could promote A549 cells apoptosis, and the effect was stronger when the concentration was ≥6.0 mL•L⁻¹. In conclusion, CSRP has the anti-cancer effect, and the action mechanism may be associated with inhibiting TERT mRNA expression, shortening telomere length, inhibiting cells proliferation and promoting cells apoptosis.

A Modified Epiglottis-Tongue Root Flap for Postoperative Laryngeal Stenosis in a Cancer Patient with a History of Radiotherapy.

Introduction: Cricohyoidoepiglottopexy (CHEP) has emerged as a promising surgical technique for treating laryngeal stenosis, offering a low rate of restenosis and a high rate of successful decannulation. However, postoperative radiation therapy can complicate open surgery for some patients due to radiation-induced cellular and tissue damage. This damage can make adequate exposure or mobilization of the larynx challenging. Case Summary: A 71-year-old male, who had undergone a partial laryngectomy 3 years prior, developed laryngeal stenosis and difficulty plugging after 35 rounds of radiotherapy. Initially, CHEP was planned, but intraoperatively, it was found that traditional CHEP would result in excessive anastomotic tension. To prevent complications, we designed an epiglottis-tongue root flap for laryngeal function reconstruction. The patient experienced no restenosis and was successfully extubated. Discussion: By separating the preepiglottal space and mobilizing the base of the tongue to construct the epiglottis-tongue root flap, modified CHEP can achieve laryngeal function reconstruction in patients postradiotherapy. It is essential to conduct a comprehensive evaluation of the patient's overall condition, degree of stenosis, tongue-to-tongue root status, and cervical tissue adhesion before surgery.

Cooperation of selenium, iron and phosphorus for simultaneously minimizing cadmium and arsenic concentrations in rice grains.

Cadmium (Cd) and arsenic (As), two toxic elements to humans, are ubiquitously coexisting contaminant found in paddy fields. The accumulation of Cd and As in rice, a major food source for many people around the world, can pose a serious threat to food safety and human health. Therefore, it is crucial to be aware of these contaminants and take adequate measures to reduce the accumulation of these two elements in rice. Developing an effective method to simultaneously reduce the accumulation of Cd) and As in rice is challenging. In this study, a pot experiment was conducted to investigate the synergistic effects of selenium (Se), iron (Fe) and phosphorus (P) on the uptake, transport and accumulation of cadmium and arsenic in rice by analyzing the physical and chemical properties of the soil, the elemental concentrations and their interrelationships in the rice tissues, and the composition and morphology of the iron plaque (IP). The results showed that the combined treatments of Se, Fe and P had positive effects on reducing Cd and As accumulation in rice, reducing Cd concentrations in brown rice by 3.86-51.88 % and As concentrations by 25.37-40.81 %. The possible mechanisms for the reduction of As and Cd concentrations in rice grains were: (i) Combined application of Fe, P and Se can effectively reduce the soil available Cd and As concentration. (ii) Combined application significantly improved the formation of IP at the tillering stage and increased the crystalline iron oxides in IP, promoting the deposition of SiO2 in rice roots, thereby effectively inhibiting the uptake of Cd and As by rice roots. (iii) Interplay and interaction between elements facilitated by transporter proteins could contribute to the synergistic mitigation of Cd and As by Se, Fe and P. This study provides a valuable new approach for effective control of Cd and As concentration of rice grown in co-contaminated soil.

FXR controls duodenogastric reflux-induced gastric inflammation through negatively regulating ER stress-associated TNXIP/NLPR3 inflammasome.

Duodenogastric reflux (DGR) is closely associated with gastric inflammation and tumorigenesis; however, the precise mechanism is unclear. Hence, we aim to clarify this molecular mechanism and design an effective therapeutic strategy based on it. The present study found that DGR induced TXNIP/NLRP3 inflammasome activation and triggered pyroptosis in gastric mucosa in vitro and in vivo, in which endoplasmic reticulum (ER) stress via PERK/eIF2α/CHOP signaling was involved. Mechanistically, farnesoid X receptor (FXR) antagonized the DGR-induced PERK/eIF2α/CHOP pathway and reduced TXNIP and NLRP3 expression. Moreover, FXR suppressed NLRP3 inflammasome activation by physically interacting with NLRP3 and caspase-1. Administration of the FXR agonist OCA protected the gastric mucosa from DGR-induced barrier disruption and mucosal inflammation. In conclusion, our study demonstrates the involvement of TXNIP/NLRP3 inflammasome-mediated pyroptosis in DGR-induced gastric inflammation. FXR antagonizes gastric barrier disruption and mucosal inflammation induced by DGR. Restoration of FXR activity may be a therapeutic strategy for DGR-associated gastric tumorigenesis.

Effect of Strain Engineering on the Spin State of the Ni-N4/C Single-Atom Catalyst and Its Consequence in Electrocatalysis.

Strain engineering is an effective strategy to improve the activity of catalysts, especially for flexible carbon-based materials. Nitrogen-coordinated single atomic metals on a carbon skeleton (M-Nx/C) are of interest in catalytic electroreduction reactions due to their high activity and atomic utilization. However, the effect of strain on the structure-activity relationship between the electrochemical activity and the electronic and geometric structures of Ni-Nx/C remains unclear. Here, we found that by applying tensile strain on the Ni-N4/C, the spin state of the single atom can be changed from a low-spin to a high-spin state. Moreover, the energy gap between the highest occupied d orbital of Ni and the lowest unoccupied molecular orbital of the adsorbed species narrowed. With an increasing strain rate, the catalytic activity of O2 and CO2 electroreduction can be improved. Especially for the 2e- O2 reduction, the implicit solvent model, constant-potential method, and microkinetic model were used to verify the positive effect of suitable stretching on the catalytic activity from thermodynamic and kinetic viewpoints. This work can reveal the relationship between strain, spin state, and the catalytic activity of Ni-Nx/C.

TBC1D4 antagonizes RAB2A-mediated autophagic and endocytic pathways.

Macroautophagic/autophagic and endocytic pathways play essential roles in maintaining homeostasis at different levels. It remains poorly understood how both pathways are coordinated and fine-tuned for proper lysosomal degradation of diverse cargoes. We and others recently identified a Golgi-resident RAB GTPase, RAB2A, as a positive regulator that controls both autophagic and endocytic pathways. In the current study, we report that TBC1D4 (TBC1 domain family member 4), a TBC domain-containing protein that plays essential roles in glucose homeostasis, suppresses RAB2A-mediated autophagic and endocytic pathways. TBC1D4 bound to RAB2A through its N-terminal PTB2 domain, which impaired RAB2A-mediated autophagy at the early stage by preventing ULK1 complex activation. During the late stage of autophagy, TBC1D4 impeded the association of RUBCNL/PACER and RAB2A with STX17 on autophagosomes by direct interaction with RUBCNL via its N-terminal PTB1 domain. Disruption of the autophagosomal trimeric complex containing RAB2A, RUBCNL and STX17 resulted in defective HOPS recruitment and eventually abortive autophagosome-lysosome fusion. Furthermore, TBC1D4 inhibited RAB2A-mediated endocytic degradation independent of RUBCNL. Therefore, TBC1D4 and RAB2A form a dual molecular switch to modulate autophagic and endocytic pathways. Importantly, hepatocyte- or adipocyte-specific tbc1d4 knockout in mice led to elevated autophagic flux and endocytic degradation and tissue damage. Together, this work establishes TBC1D4 as a critical molecular brake in autophagic and endocytic pathways, providing further mechanistic insights into how these pathways are intertwined both in vitro and in vivo.Abbreviations: ACTB: actin beta; ATG9: autophagy related 9; ATG14: autophagy related 14; ATG16L1: autophagy related 16 like 1; CLEM: correlative light electron microscopy; Ctrl: control; DMSO: dimethyl sulfoxide; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; FL: full length; GAP: GTPase-activating protein; GFP: green fluorescent protein; HOPS: homotypic fusion and protein sorting; IP: immunoprecipitation; KD: knockdown; KO: knockout; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; OE: overexpression; PG: phagophore; PtdIns3K: class III phosphatidylinositol 3-kinase; SLC2A4/GLUT4: solute carrier family 2 member 4; SQSTM1/p62: sequestosome 1; RUBCNL/PACER: rubicon like autophagy enhancer; STX17: syntaxin 17; TAP: tandem affinity purification; TBA: total bile acid; TBC1D4: TBC1 domain family member 4; TUBA1B: tubulin alpha 1b; ULK1: unc-51 like autophagy activating kinase 1; VPS39: VPS39 subunit of HOPS complex; WB: western blot; WT: wild type.

Simultaneously inhibit cadmium and arsenic uptake in rice (Oryza sativa L.) by Selenium enhanced iron plaque: Performance and mechanism.

Selenium (Se) fortification is witnessed to simultaneously inhibit absorbing Cadmium (Cd) and Arsenic (As) by rice plants, but the mechanism is unclear. Here, the effects of Se on the root morphology, iron plaque (IP) content, soil Fe2+ content, radial oxygen loss (ROL), and enzyme activities of the rice plants in the soil contaminated by Cd and As were intensively investigated through the hydroponic and soil experiments. Se effectively alleviated the toxic effects of Cd and As on the plants and the dry weight, root length, and root width were increased by 203.18%, 33.41%, and 52.81%, respectively. It also elucidated that ROL was one of the key factors to elevate IP formation by Se and the specific pathways of Se enhancing ROL were identified. ROL of the plants in the experiment group treated by Se was increased 36.76%, and correspondingly IP was magnified 50.37%, compared to the groups with Cd and As. It was owing to Se significantly increased the root porosity (62.11%), facilitating O2 transport to the roots. Additionally, Se enhanced the activities of catalase (CAT) and superoxide dismutase (SOD) to promote the catalytic degradation of ROS induced by Cd and As stress. It indirectly increased O2 release in the rhizosphere, which benefit to form more robust IP serve as stronger barrier to Cd and As. The results of our study provide a novel molecular level insight for Se promoting root IP to block Cd and As uptake by the rice plants.