Objective: To investigate the mechanism that hypoxia promotes the migration of lung adenocarcinoma A549 cells. Methods: A549 cells were cultured and cells that knockdown of acetyl-CoA carboxylase 1 (ACC1) were obtained by transfection with lentivirus, and cells that knockdown of sterol regulatory element-binding proteins-1 (SREBP-1) were obtained by treated with si-RNA. A549 cells were treated with hypoxia combined with hypoxia inducible factor-1α (HIF-1α) inhibitor PX-478 (25 μmol); Hypoxia combined with linoleic acid (LA) (20 μmol) treated A549 cells with ACC1 knockdown, and A549 cells with SREBP-1 knockdown were treated by hypoxia. Transwell migration assay was used to detect cell migration. Western blot was conducted to detect HIF-1α, ACC1 and epithelial mesenchymal transition (EMT) related proteins, Vimentin, E-Cadherin and SREBP-1; Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was performed to detect the changes of ACC1 and SREBP-1 mRNA in A549 cells after hypoxia and HIF-1α inhibitor PX-478 (25 μmol) treatment. Each experiment was repeated three times. Results: Compared with the normoxic control group, hypoxia promoted the migration of A549 cells (P＜0.01), and up-regulated the expressions of ACC1, HIF-1α (all P＜0.01) and SREBP-1 (P＜0.05). PX-478 (25 μmol) inhibited the migration of A549 cells induced by hypoxia and down-regulated the expression of SREBP-1 (all P＜0.05). ACC1 mRNA and SREBP-1 mRNA levels were increased after hypoxia treatment of A549 cells (all P＜0.05). The levels of ACC1 mRNA and SREBP-1 mRNA were decreased after A549 cells treated with hypoxia combined with PX-478 (25 μmol) for 24 h (P＜0.05, P＜0.01). Knockdown of SREBP-1 in A549 cells was obtained by transfection with si-RNA. Transwell migration assay showed the number of cell migration in si-SREBP-1 group was less than that in normoxia control group (P＜0.01). The si-SREBP-1 group and the si-NC group were treated with hypoxia. Compared with the control group, the number of cell migration in the si-SREBP-1 group was decreased (P＜0.01), however, the difference was not statistically significant compared with the normoxia si-SREBP-1 group (P＞0.05). Western blot showed that the expression of ACC1 in the si-SREBP-1 group was lower than that in the control group (P＜0.01). Compared with the control group, the expression of ACC1 was decreased after si-SREBP-1 group treated with hypoxia (P＜0.01). Knockdown of ACC1 inhibited the migration of A549 cells (P＜0.05). After knockdown of ACC1, the migration number of A549 cells under normoxia and 5% O₂ conditions had no significant difference (P＞0.05). Application of LA under hypoxia condition rescued ACC1-knockdown induced inhibitory effect on hypoxia-promoted A549 cell migration (P＜0.05). Conclusion: Hypoxia promotes migration of lung adenocarcinoma A549 cells by regulating fatty acid metabolism through HIF-1α/SREBP-1/ACC1 pathway.
A549 Cells ; Acetyl-CoA Carboxylase ; Adenocarcinoma of Lung ; Cell Hypoxia/physiology* ; Cell Line, Tumor ; Humans ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit ; Lung Neoplasms ; RNA/metabolism* ; RNA, Messenger/metabolism* ; Sterol Regulatory Element Binding Protein 1/metabolism*

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.
Animals ; Antiviral Agents ; pharmacology ; therapeutic use ; Betacoronavirus ; drug effects ; physiology ; Binding Sites ; drug effects ; Cell Line ; Coronavirus Infections ; drug therapy ; virology ; Crotonates ; pharmacology ; Cytokine Release Syndrome ; drug therapy ; Drug Evaluation, Preclinical ; Gene Knockout Techniques ; Humans ; Influenza A virus ; drug effects ; Leflunomide ; pharmacology ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections ; drug therapy ; Oseltamivir ; therapeutic use ; Oxidoreductases ; antagonists & inhibitors ; metabolism ; Pandemics ; Pneumonia, Viral ; drug therapy ; virology ; Protein Binding ; drug effects ; Pyrimidines ; biosynthesis ; RNA Viruses ; drug effects ; physiology ; Structure-Activity Relationship ; Toluidines ; pharmacology ; Ubiquinone ; metabolism ; Virus Replication ; drug effects

Polypyrimidine tract-binding protein 1 (PTBP1) plays an essential role in splicing and is expressed in almost all cell types in humans, unlike the other proteins of the PTBP family. PTBP1 mediates several cellular processes in certain types of cells, including the growth and differentiation of neuronal cells and activation of immune cells. Its function is regulated by various molecules, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and RNA-binding proteins. PTBP1 plays roles in various diseases, particularly in some cancers, including colorectal cancer, renal cell cancer, breast cancer, and glioma. In cancers, it acts mainly as a regulator of glycolysis, apoptosis, proliferation, tumorigenesis, invasion, and migration. The role of PTBP1 in cancer has become a popular research topic in recent years, and this research has contributed greatly to the formulation of a useful therapeutic strategy for cancer. In this review, we summarize recent findings related to PTBP1 and discuss how it regulates the development of cancer cells.
Alternative Splicing ; Carcinogenesis ; Glycolysis ; Heterogeneous-Nuclear Ribonucleoproteins/physiology* ; Humans ; MicroRNAs/physiology* ; Neoplasms/pathology* ; Polypyrimidine Tract-Binding Protein/physiology* ; RNA, Long Noncoding/physiology*

Diabetic nephropathy (DN) is currently the most common complication of diabetes. It is considered to be one of the leading causes of end-stage renal disease (ESRD) and affects many diabetic patients. The pathogenesis of DN is extremely complex and has not yet been clarified; however, in recent years, increasing evidence has shown the important role of innate immunity in DN pathogenesis. Pattern recognition receptors (PRRs) are important components of the innate immune system and have a significant impact on the occurrence and development of DN. In this review, we classify PRRs into secretory, endocytic, and signal transduction PRRs according to the relationship between the PRRs and subcellular compartments. PRRs can recognize related pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), thus triggering a series of inflammatory responses, promoting renal fibrosis, and finally causing renal impairment. In this review, we describe the proposed role of each type of PRRs in the development and progression of DN.
Alarmins/physiology* ; C-Reactive Protein/physiology* ; Diabetic Nephropathies/etiology* ; Endocytosis ; Humans ; Immunity, Innate ; Mannose-Binding Lectin/physiology* ; Pathogen-Associated Molecular Pattern Molecules ; Receptors, Pattern Recognition/physiology* ; Serum Amyloid P-Component/physiology* ; Signal Transduction

Metastasis is one of the main reasons causing death in cancer patients. It was reported that chemotherapy might induce metastasis. In order to uncover the mechanism of chemotherapy-induced metastasis and find solutions to inhibit treatment-induced metastasis, the relationship between epithelial-mesenchymal transition (EMT) and doxorubicin (DOX) treatment was investigated and a redox-sensitive small interfering RNA (siRNA) delivery system was designed. DOX-related reactive oxygen species (ROS) were found to be responsible for the invasiveness of tumor cells in vitro, causing enhanced EMT and cytoskeleton reconstruction regulated by Ras-related C3 botulinum toxin substrate 1 (RAC1). In order to decrease RAC1, a redox-sensitive glycolipid drug delivery system (chitosan-ss-stearylamine conjugate (CSO-ss-SA)) was designed to carry siRNA, forming a gene delivery system (CSO-ss-SA/siRNA) downregulating RAC1. CSO-ss-SA/siRNA exhibited an enhanced redox sensitivity compared to nonresponsive complexes in 10 mmol/L glutathione (GSH) and showed a significant safety. CSO-ss-SA/siRNA could effectively transmit siRNA into tumor cells, reducing the expression of RAC1 protein by 38.2% and decreasing the number of tumor-induced invasion cells by 42.5%. When combined with DOX, CSO-ss-SA/siRNA remarkably inhibited the chemotherapy-induced EMT in vivo and enhanced therapeutic efficiency. The present study indicates that RAC1 protein is a key regulator of chemotherapy-induced EMT and CSO-ss-SA/siRNA silencing RAC1 could efficiently decrease the tumor metastasis risk after chemotherapy.
Amines/chemistry* ; Antineoplastic Agents/adverse effects* ; Breast Neoplasms/pathology* ; Chitosan/chemistry* ; Doxorubicin/adverse effects* ; Drug Delivery Systems ; Epithelial-Mesenchymal Transition/drug effects* ; Female ; Humans ; MCF-7 Cells ; Neoplasm Metastasis/prevention & control* ; Oxidation-Reduction ; RNA, Small Interfering/administration & dosage* ; Reactive Oxygen Species/metabolism* ; rac1 GTP-Binding Protein/physiology*

The aim of this study was to investigate the role of S100 calcium binding protein A16 (S100A16) in lipid metabolism in hepatocytes and its possible biological mechanism. HepG2 cells (human hepatoma cell line) were cultured with fatty acid to establish fatty acid culture model. The control model was cultured without fatty acid. Each model was divided into three groups and transfected with S100a16 over-expression, shRNA and vector plasmids, respectively. The concentration of triglyceride (TG) in the cells was measured by kit, and the lipid droplets was observed by oil red O staining. Immunoprecipitation and mass spectrometry were used to find the interesting proteins interacting with S100A16, and the interaction was verified by immunoprecipitation. The further mechanism was studied by Western blot and qRT-PCR. The results showed that the intracellular lipid droplet and TG concentrations in the fatty acid culture model were significantly higher than those in the control model. The accumulation of intracellular fat in the S100a16 over-expression group was significantly higher than that in the vector plasmid transfection group. There was an interaction between heat shock protein A5 (HSPA5) and S100A16. Over-expression of S100A16 up-regulated protein expression levels of HSPA5, inositol-requiring enzyme 1α (IRE1α) and pIREα1, which belong to endoplasmic reticulum stress HSPA5/IRE1α-XBP1 pathway. Meanwhile, over-expression of S100A16 up-regulated the mRNA expression levels of adipose synthesis-related gene Srebp1c, Acc and Fas. In the S100a16 shRNA plasmid transfection group, the above-mentioned protein and mRNA levels were lower than those of vector plasmid transfection group. These results suggest that S100A16 may promote lipid synthesis in HepG2 cells through endoplasmic reticulum stress HSPA5/IRE1α-XBP1 pathway.
Endoplasmic Reticulum Stress ; Endoribonucleases ; physiology ; Heat-Shock Proteins ; physiology ; Hep G2 Cells ; Humans ; Lipid Metabolism ; Protein-Serine-Threonine Kinases ; physiology ; S100 Proteins ; physiology ; Triglycerides ; biosynthesis ; X-Box Binding Protein 1 ; physiology

OBJECTIVE: To estimate the detrimental effects of shortwave exposure on rat hippocampal structure and function and explore the underlying mechanisms. METHODS: One hundred Wistar rats were randomly divided into four groups (25 rats per group) and exposed to 27 MHz continuous shortwave at a power density of 5, 10, or 30 mW/cm2 for 6 min once only or underwent sham exposure for the control. The spatial learning and memory, electroencephalogram (EEG), hippocampal structure and Nissl bodies were analysed. Furthermore, the expressions of N-methyl-D-aspartate receptor (NMDAR) subunits (NR1, NR2A, and NR2B), cAMP responsive element-binding protein (CREB) and phosphorylated CREB (p-CREB) in hippocampal tissue were analysed on 1, 7, and 14 days after exposure. RESULTS: The rats in the 10 and 30 mW/cm2 groups had poor learning and memory, disrupted EEG oscillations, and injured hippocampal structures, including hippocampal neurons degeneration, mitochondria cavitation and blood capillaries swelling. The Nissl body content was also reduced in the exposure groups. Moreover, the hippocampal tissue in the 30 mW/cm2 group had increased expressions of NR2A and NR2B and decreased levels of CREB and p-CREB. CONCLUSION Shortwave exposure (27 MHz, with an average power density of 10 and 30 mW/cm2) impaired rats' spatial learning and memory and caused a series of dose-dependent pathophysiological changes. Moreover, NMDAR-related CREB pathway suppression might be involved in shortwave-induced structural and functional impairments in the rat hippocampus.
Animals ; Cyclic AMP Response Element-Binding Protein ; genetics ; metabolism ; Dose-Response Relationship, Radiation ; Electroencephalography ; radiation effects ; Hippocampus ; radiation effects ; Male ; Memory ; radiation effects ; Nissl Bodies ; physiology ; radiation effects ; Radio Waves ; adverse effects ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, N-Methyl-D-Aspartate ; genetics ; metabolism ; Spatial Learning ; radiation effects

BackgroundA high consumption of fructose leads to hepatic steatosis. About 20-30% of triglycerides are synthesized via de novo lipogenesis. Some studies showed that endoplasmic reticulum stress (ERS) is involved in this process, while others showed that a lipotoxic environment directly influences ER homeostasis. Here, our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 (XBP-1), one marker of ERS, on hepatic lipid accumulation stimulated by high fructose.

MethodsHepG2 cells were incubated with different concentrations of fructose. Upstream regulators of de novo lipogenesis (i.e., carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1c [SREBP-1c]) were measured by polymerase chain reaction and key lipogenic enzymes (acetyl-CoA carboxylase [ACC], fatty acid synthase [FAS], and stearoyl-CoA desaturase-1 [SCD-1]) by Western blotting. The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid (TUDCA) or the ERS inducer thapsigargin. Finally, the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection.

ResultsExposure to high fructose increased triglyceride levels in a dose- and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels of FAS, ACC, and SCD-1, concomitant with XBP-1 conversion to an active spliced form. Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin. Triglyceride level in XBP-1-deficient group decreased significantly compared with high-fructose group (4.41 ± 0.54 μmol/g vs. 6.52 ± 0.38 μmol/g, P < 0.001), as mRNA expressions of SREBP-1c (2.92 ± 0.46 vs. 5.08 ± 0.41, P < 0.01) and protein levels of FAS (0.53 ± 0.06 vs. 0.85 ± 0.05, P = 0.01), SCD-1 (0.65 ± 0.06 vs. 0.90 ± 0.04, P = 0.04), and ACC (0.38 ± 0.03 vs. 0.95 ± 0.06, P < 0.01) decreased. Conversely, levels of triglyceride (4.22 ± 0.54 μmol/g vs. 2.41 ± 0.35 μmol/g, P < 0.001), mRNA expression of SREBP-1c (2.70 ± 0.33 vs. 1.00 ± 0.00, P < 0.01), and protein expression of SCD-1 (0.93 ± 0.06 vs. 0.26 ± 0.05, P < 0.01), ACC (0.98 ± 0.09 vs. 0.43 ± 0.03, P < 0.01), and FAS (0.90 ± 0.33 vs. 0.71 ± 0.02, P = 0.04) in XBP-1s-upregulated group increased compared with the untransfected group.

ConclusionsERS is associated with de novo lipogenesis, and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.

Endoplasmic Reticulum Stress ; physiology ; Fatty Liver ; Fructose ; metabolism ; Hep G2 Cells ; Humans ; Lipogenesis ; physiology ; Liver ; Sterol Regulatory Element Binding Protein 1 ; X-Box Binding Protein 1 ; physiology

Animals ; Fragile X Mental Retardation Protein ; metabolism ; Fragile X Syndrome ; metabolism ; Humans ; Neurons ; metabolism ; RNA-Binding Proteins ; metabolism ; Receptor, Metabotropic Glutamate 5 ; metabolism ; Sumoylation ; physiology

Alzheimer's disease (AD) is the most common form of dementia among the elderly, characterized by amyloid plaques, neurofibrillary tangles, and neuroinflammation in the brain, as well as impaired cognitive behaviors. A sex difference in the prevalence of AD has been noted, while sex differences in the cerebral pathology and relevant molecular mechanisms are not well clarified. In the present study, we systematically investigated the sex differences in pathological characteristics and cognitive behavior in 12-month-old male and female APP/PS1/tau triple-transgenic AD mice (3×Tg-AD mice) and examined the molecular mechanisms. We found that female 3×Tg-AD mice displayed more prominent amyloid plaques, neurofibrillary tangles, neuroinflammation, and spatial cognitive deficits than male 3×Tg-AD mice. Furthermore, the expression levels of hippocampal protein kinase A-cAMP response element-binding protein (PKA-CREB) and p38-mitogen-activated protein kinases (MAPK) also showed sex difference in the AD mice, with a significant increase in the levels of p-PKA/p-CREB and a decrease in the p-p38 in female, but not male, 3×Tg-AD mice. We suggest that an estrogen deficiency-induced PKA-CREB-MAPK signaling disorder in 12-month-old female 3×Tg-AD mice might be involved in the serious pathological and cognitive damage in these mice. Therefore, sex differences should be taken into account in investigating AD biomarkers and related target molecules, and estrogen supplementation or PKA-CREB-MAPK stabilization could be beneficial in relieving the pathological damage in AD and improving the cognitive behavior of reproductively-senescent females.
Alzheimer Disease ; metabolism ; pathology ; psychology ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Cyclic AMP-Dependent Protein Kinases ; metabolism ; Disease Models, Animal ; Female ; Hippocampus ; metabolism ; pathology ; Humans ; Inflammation ; metabolism ; pathology ; psychology ; Male ; Maze Learning ; physiology ; Mice, Inbred C57BL ; Mice, Transgenic ; Neurofibrillary Tangles ; metabolism ; pathology ; Plaque, Amyloid ; metabolism ; pathology ; psychology ; Presenilin-1 ; genetics ; metabolism ; Sex Characteristics ; Spatial Memory ; physiology ; p38 Mitogen-Activated Protein Kinases ; metabolism ; tau Proteins ; genetics ; metabolism