Human disease-causing mutations result in loss of leiomodin 2 through nonsense-mediated mRNA decay.

The leiomodin (Lmod) family of actin-binding proteins play a critical role in muscle function, highlighted by the fact that mutations in all three family members (LMOD1-3) result in human myopathies. Mutations in the cardiac predominant isoform, LMOD2 lead to severe neonatal dilated cardiomyopathy. Most of the disease-causing mutations in the LMOD gene family are nonsense, or frameshift, mutations predicted to result in expression of truncated proteins. However, in nearly all cases of disease, little to no LMOD protein is expressed. We show here that nonsense-mediated mRNA decay, a cellular mechanism which eliminates mRNAs with premature termination codons, underlies loss of mutant protein from two independent LMOD2 disease-causing mutations. Furthermore, we generated steric-blocking oligonucleotides that obstruct deposition of the exon junction complex, preventing nonsense-mediated mRNA decay of mutant LMOD2 transcripts, thereby restoring mutant protein expression. Our investigation lays the initial groundwork for potential therapeutic intervention in LMOD-linked myopathies.

CPXM1 correlates to poor prognosis and immune cell infiltration in gastric cancer.

Background: Gastric cancer (GC) is the fourth most common cause of cancer-related death and the fifth most frequent malignant cancer, especially advanced GC. Carboxypeptidase X member 1 (CPXM1) is an epigenetic factor involved in many physiological processes, including osteoclast differentiation and adipogenesis. Several studies have shown the association of CPXM1 with multiple tumors; however, the mechanism of CPXM1 involvement in the progression of GC is yet to be characterized. Method: CPXM1 expression data were obtained from the Tumor Immune Estimation Resource. The Cancer Genome Atlas and the Gene Expression Omnibus databases were used to obtain patient-matched clinicopathological information, and the Kaplan-Meier plot database was utilized for the prognosis analysis of GC patients. The Catalog of Somatic Mutations in Cancer and cBioportal databases were adopted to study CPXM1 mutations in tumors. Next, we utilized the Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment Analysis for mechanism research. Furthermore, we performed tumor microenvironment and immune infiltration analysis based on CPXM1. Finally, we predicted sensitivity to several targeted drugs in GC patients based on CPXM1.CPXM1 is upregulated in GC and is correlated with poor prognosis, gender, and tumor stage in GC patients. Gene enrichment analysis suggested that CPXM1 may regulate the occurrence and progression of GC via the PI3K-AKT and TGF-ß pathway. Moreover, CPXM1 expression results in an increase in the proportion of immune and stromal cells. Additionally, the proportion of plasma cells was inversely related to the expression of CPXM1, whereas macrophage M2 expression was proportionate to CPXM1 expression. Finally, six small-molecule drugs that showed notable variations in IC50 between two groups were screened. Conclusion: These results suggested that CPXM1 regulates the progression of GC and may represent a novel target for the detection and treatment of GC.

Finite element analysis comparison of Type 42A2 fracture fixed with external titanium alloy locking plate and traditional external fixation frame.

BACKGROUND: At present, not all Type AO/OTA 42A2 open fractures can be treated by external fixation brackets, not to mention the inconvenience of this technique in clinical practice. External titanium alloy locking plates, which are lightweight and easy-to-operate, can be used as an alternative treatment option for such patients. However, there are few reports of finite element biomechanical analysis on the titanium alloy locking plates and fixation brackets being placed on the medial side of the tibial fracture. In this study, the biomechanical properties of titanium alloy locking plates and fixation brackets for treating Type AO/OTA 42A2 fractures were compared by applying the finite element method, and the results provided data support for the clinical application of the external titanium alloy locking plate technique. METHODS: Type AO/OTA 42A2 fracture models were constructed using CT data of a male volunteer for two external fixation techniques, namely the external titanium alloy locking plate technique and the external fixation bracket technique, according to commonly-used clinical protocols. Then, the four-point bending, axial compression, clockwise rotation and counterclockwise rotation tests under the maximum load were simulated in finite element analysis software. The stress distribution, peak stress and overall tibial displacement data for the two different external fixation techniques were obtained and compared. RESULTS: In the four different test conditions (i.e., four-point bending, axial compression, clockwise torsion, counterclockwise torsion) under the maximum load, the two external fixation techniques showed obvious von Mises stress concentration at the contacts between the screw and tibia, between the screw and titanium alloy locking plate, between the self-tapping self-drilling needle and tibia, between the self-tapping self-drilling needle and the external fixation device, as well as around the fracture end and around the cortical bone at the upper and lower ends of the tibia. The peak stress was ranged 26.67-558.77 MPa, all below the yield stress strength of titanium alloy. The peak tibial displacement of the external titanium alloy locking plate model was smaller than that of the fixation bracket model. In terms of structural stability, the external titanium alloy locking plate technique was superior to the external fixation bracket technique. CONCLUSIONS: When fixing Type AO/OTA 42A2 fractures, external titanium alloy locking plates are not only lightweight and easy-to-operate, but also have better performance in terms of axial compression, bending and torsion resistance. According to the finite element biomechanical analysis, external titanium alloy locking plates are superior to traditional external fixation brackets in treating Type AO/OTA 42A2 fractures and can better meet the needs of clinical application.

Acute neck tendonitis with dyspnea: A case report.

BACKGROUND: Longus colli tendinitis (LCT) with dyspnea is a relatively less-reported condition in the literature, and physicians should be aware of its existence. Misdiagnosis of this condition may cause unnecessary treatment for dyspnea. CASE SUMMARY: Herein, we report the case of a 40-year-old man with acute neck tendonitis. The patient presented to the pneumology department clinic with a complaint of acute neck tendonitis with dyspnea. An emergency cervical magnetic resonance examination was performed, and the preliminary diagnosis was "acute longus cervicalis tendinitis." After aggressive medical treatment, the symptoms obviously improved. CONCLUSION: LCT is a self-limiting disease that usually improves after three to seven days of conservative treatment following a definite diagnosis. However, owing to its insidious onset and complex clinical manifestations, most relevant personnel are not fully understood. The definite diagnosis of LCT is based on a comprehensive understanding of the triad, rare symptoms, and the clear identification of cervical 1 and 2 levels calcification and prevertebral edema by medical imaging examination, especially magnetic resonance imaging and computed tomography.

Effects of shading intensity on growth and quality of Artemisia stolonifera / 中国中药杂志

The purpose of this study was to analyze the effects of shading intensity on the growth, yield, and quality of Artemisia stolonifera so as to provide references for the artificial cultivation of A. stolonifera. The seedlings of A. stolonifera with consistent growth underwent shading treatment at four shading intensity levels(0, 55%, 85%, and 95%) with different layers of black shading nets. The agronomic indexes, yield, moxa yield, total ash, quality characteristics of moxa during combustion and pyrolysis, main volatile components, flavonoids, and phenolic acids were measured. The results showed that under shading conditions, the stem diameter, leaf width, 5-leaf spacing, branch number, and yield of A. stolonifera decreased significantly, while the plant height, leaf length, leaf number, chlorophyll content, and moxa yield increased first and then decreased with the increase in shading intensity. The burning performance of moxa under natural light was better than that under moderate and severe shading conditions. The content of eucalyptol first increased and then decreased with the increase in shading intensity. The humulene content was negatively correlated with shading intensity. Other major volatile components showed no significant difference under various shading conditions. The content of neochlorogenic acid, cryptochlorogenic acid, isoschaftoside, and isochlorogenic acid B was positively correlated with shading intensity, while the content of chlorogenic acid, isochlorogenic acid A, and isochlorogenic acid C decreased first and then increased with the increase in shading intensity. To sum up, A. stolonifera is a light-loving plant, and shading can greatly reduce the yield, the content of internal components, and the burning performance of moxa. It is the main reason why A. stolonifera is mainly distributed in the forest edge, open forest, roadside, and wasteland grass in the middle and high mountains in the wild. For artificial domestication and cultivation of A. stolonifera, it is better to select plots with sufficient light.

Circ-CCS enhances autophagy during imatinib resistance of gastrointestinal stromal tumor by regulating miR-197-3p/ATG10 signaling.

Context: Drug resistance in gastrointestinal stromal tumors (GISTs) is connected with autophagy activation. Accumulating data demonstrates the critical role of circular RNAs (circRNAs) dysregulation in this development. Aim: To explore the possible function of hsa_circ_0092306 (circ-CCS) in GIST imatinib resistance. Materials and Methods: Quantitative real-time reverse transcription PCR (RT-qPCR) was used to determine the expression levels of circ-CCS and miR-197-3p. The vitality and apoptosis of cells were determined using the Cell Counting Kit-8 and TUNEL assays, respectively. Western blot analysis was used to evaluate the relative protein expression. A dual-luciferase reporter assay was used to validate the link between circ-CCS, miR-197-3p, and ATG10. Statistical Analysis Used: Comparisons of two groups were analyzed using Student's t tests, and analysis of variance (ANOVA) with Tukey's post hoc test was used to compare three or more groups. Results: Circulating-CCS expression was considerably increased in the serum of imatinib-resistant GIST patients (P < 0.001). Circulating-CCS deficiency decreased cell proliferation and autophagy in GIST-882 and GIST-T1 cells, but promoted apoptosis (P < 0.05). Additionally, circ-CCS was predominantly found in the cytoplasm. Mechanically, circ-CCS targeted miR-197-3p, which may influence autophagy by downregulating ATG10, in order to modulate GIST cells' malignant tendencies. Moreover, silencing miR-197-3p reversed the effect of circ-CCS knockdown on apoptosis and autophagy in GIST cells. Conclusions: By modulating the miR-197-3p/ATG10 axis, circ-CCS increased imatinib resistance in GIST cells, establishing a potential target for reversing medication resistance in such patients.

Effect of Thermal Stimulus on Kinetic Rehydration of Thermoresponsive Poly(diethylene glycol monomethyl ether methacrylate)-block-poly(poly(ethylene glycol) methyl ether methacrylate) Thin Films Probed by In Situ Neutron Reflectivity.

The kinetic rehydration of thin di-block copolymer poly(diethylene glycol monomethyl ether methacrylate)-block-poly(poly(ethylene glycol) methyl ether methacrylate) (PO2-b-PO300) films containing two thermoresponsive components is probed by in situ neutron reflectivity (NR) with different thermal stimuli in the D2O vapor atmosphere. The transition temperatures (TTs) of PO2 and PO300 blocks are 25 and 60 °C, respectively. After the one-step stimulus (rapid decrease in temperature from 60 to 20 °C), the film directly switches from a collapsed to a fully swollen state. The rehydration process is divided into four steps: (a) D2O condensation, (b) D2O absorption, (c) D2O evaporation, and (d) film reswelling. However, the film presents a different rehydration behavior when the thermal stimulus is separated into two smaller steps (first decrease from 60 to 40 °C and then to 20 °C). The film first switches from a collapsed to a semiswollen state caused by the rehydrated PO300 blocks after the first step of thermal stimulus (60 to 40 °C) and then to a swollen state induced by the rehydrated PO2 blocks after the second step (40 to 20 °C). Thus, the kinetic responses are distinct from that after the one-step thermal stimulus. Both the time and extent of condensation as well as evaporation processes are significantly reduced in these two smaller steps. However, the final states of the rehydrated PO2-b-PO300 films are basically identical irrespective of the applied thermal stimulus. Thus, the final state of thermoresponsive di-block copolymer films is not affected by the external thermal stimuli, which is beneficial for the design and preparation of sensors or switches based on thermoresponsive polymer films.

Metformin protects against abdominal aortic aneurysm by Atg7-induced autophagy.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a pathological dilation of the abdominal aorta. It is often asymptomatic, yet it has a high susceptibility to rupture. Our previous study showed that metformin protected against the pathophysiology of AAA by reducing the activation of the PI3K/AKT/mTOR pathway. OBJECTIVES: To investigate the potential involvement of the autophagy-related pathways in AAA and the ability of metformin to modulate these effects. MATERIAL AND METHODS: The expression of autophagy-related proteins was detected with western blot in patients with AAA. Angiotensin II (Ang-II) was also used to construct an AAA model in mice and in vascular smooth muscle cells (VSMCs). The expression of Atg7 and Atg4 was determined using western blot assay. The Atg7 expression was regulated by overexpressed plasmid, siRNA (small interfering RNA), or metformin, and cell proliferation, migration, apoptosis and autophagy caused by Ang-II were examined. RESULTS: Autophagy-related proteins were increased in patients with AAA. The Ang-II also induced the expression of Atg7, and metformin reversed this effect both in vivo and in vitro. The suppression of Atg7 inhibited cell proliferation and cell migration, and reduced cell apoptosis and autophagy, while the overexpression of Atg7 enhanced cell proliferation and migration, and induced cell apoptosis and autophagy. Furthermore, Atg7 regulated the expression of the autophagy-related protein in Ang-II treated VSMCs. The Atg7-mediated autophagy was also attenuated by metformin. CONCLUSIONS: Metformin reduced autophagy in AAA and this effect was mediated by Atg7, suggesting that Atg7 is a potential downstream effector of metformin in protecting against the pathophysiology of AAA.

Remote ischemic post­conditioning alleviates ischemia/reperfusion­induced intestinal injury via the ERK signaling pathway­mediated RAGE/HMGB axis.

Intestinal ischemia reperfusion (I/R) injury is a tissue and organ injury that frequently occurs during surgery and significantly contributes to the pathological processes of severe infection, injury, shock, cardiopulmonary insufficiency and other diseases. However, the mechanism of intestinal I/R injury remains to be elucidated. A mouse model of intestinal I/R injury was successfully established and the model mice were treated with remote ischemic post­conditioning (RIPOC) and/or an ERK inhibitor (CC­90003), respectively. Histopathological changes of the intestinal mucosa were determined by hematoxylin and eosin staining. In addition, the levels of high­mobility group box 1 (HMGB1) and receptor for advanced glycation end products (RAGE) expression were confirmed by reverse transcription­quantitative polymerase chain reaction, western blotting and immunohistochemistry assays. The levels of antioxidants, oxidative stress markers (8­OHdG) and interleukin 1 family members were evaluated by ELISA assays and the levels of NF­κB pathway proteins were analyzed by western blotting. The data demonstrated that RIPOC could attenuate the histopathological features of intestinal mucosa in the intestinal I/R­injury mouse models via the ERK pathway. It was also revealed that HMGB1 and RAGE expression in the mouse models could be markedly reduced by RIPOC (P<0.05) and that these reductions were associated with inhibition of the ERK pathway. Furthermore, it was demonstrated that RIPOC produced significant antioxidant and anti­inflammatory effects following an intestinal I/R injury and that these effects were mediated via the ERK pathway (P<0.05). In addition, RIPOC was demonstrated to suppress the NF­κB (p65)/NLR family pyrin domain containing 3 (NLRP3) inflammatory pathways in the intestinal I/R injury mouse models via the ERK pathway. The findings of the present study demonstrated that RIPOC helped to protect mice with an intestinal I/R injury by downregulating the ERK pathway.

Two Transition Metal Coordination Polymers: Luminescent Sensing Properties and Treatment Effect on Chronic Periodontitis by Reducing IL-6 and TNF-α Content.

Two novel sulfonic functionalized coordination polymers (CPs) {[Cd1.5(dimb)(5-sip)(H2O)3]·3H2O}n (1, dimb = 1,4-di(1H-imidazol-1-yl)butane) and [Co2(iptz)(Hiptz)(5-sip)(H2O)]·4H2O (2, Hiptz = 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole) were acquired via different metal(II) salts reacting with the mixed ligands containing 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole, 1,4-di(1H-imidazol-1-yl)butane and sodium 5-sulfoisophthalate (NaH2sip), respectively. Furthermore, the complex 1 based on Cd(II) could be utilized as the luminescent senor for picric acid (PA) detection in water. In bio-research, compounds 1 and 2 treatment effect on chronic periodontitis was assessed and the specific mechanism was discussed. First of all, the RT-PCR was performed to measure the HmuY and fimA genes relative expression level in P.gingivalis after treated by compounds 1 and 2. Then, the TNF-α and IL-6 content in the fluid of gingival crevicular after compounds treatment was determined with ELISA detection kit.

IFI16 contributes to the pathogenesis of abdominal aortic aneurysm by regulating the caspase-1/IL-1ß/MCPIP1 pathway.

AIMS: Abdominal aortic aneurysm (AAA) is a multi-factorial progressive vascular disease characterized by chronic inflammatory cell infiltration. We investigated the roles played by IFI16 and ASC inflammasomes in AAA development and progression. MATERIALS AND METHODS: Western blot and qRT-PCR studies were performed to analyze the expression of relative genes in AAA specimens and mouse vascular smooth muscle cells (VSMCs). The apoptosis rates and ROS levels of VSMCs were assessed by flow cytometry. Transwell assays were performed to analyze the migration ability of VSMCs. The levels of MCP-1, IL-1ß, and IL-6 in the supernatants of cultured VSMCs were analyzed by ELISA. KEY FINDINGS: Increased levels of IFI16 expression were found in AAA specimens and Ang-II-treated VSMCs. IFI16 and ASC silencing suppressed the apoptosis and migration ability of VSMCs undergoing Ang-II treatment, reduced elasticity damage to the aortic wall, and decreased the levels of MMP expression. The effect of IFI16 knockdown in Ang-II-induced VSMCs was reversed by MCPIP1 overexpression. SIGNIFICANCE: Our data suggest that an up-regulation of IFI16 and ASC expression might promote the apoptosis of VSMCs, enhance the inflammatory response, and impairs vascular wall elasticity via a MCPIP1-related mechanism. The inflammasome components IFI16 and ASC might be involved in AAA progression and serve as target molecules for diagnosing and treating AAA.

Impact of Thermal History on the Kinetic Response of Thermoresponsive Poly(diethylene glycol monomethyl ether methacrylate)-block-poly(poly(ethylene glycol)methyl ether methacrylate) Thin Films Investigated by In Situ Neutron Reflectivity.

The impact of thermal history on the kinetic response of thin thermoresponsive diblock copolymer poly(diethylene glycol monomethyl ether methacrylate)-block-poly(poly(ethylene glycol) methyl ether methacrylate), abbreviated as PMEO2MA-b-POEGMA300, films is investigated by in situ neutron reflectivity. The PMEO2MA and POEGMA300 blocks are both thermoresponsive polymers with a lower critical solution temperature. Their transition temperatures (TTs) are around 25 °C (TT1, PMEO2MA) and 60 °C (TT2, POEGMA300). Thus, by applying different temperature protocols (20 to 60 or 20 to 40 to 60 °C), the PMEO2MA-b-POEGMA300 thin films experience different thermal histories: the first protocol directly switches from a swollen to a collapsed state, whereas the second one switches first from a swollen to a semicollapsed and finally to a collapsed state. Although the applied thermal histories differ, the response and final state of the collapsed films are very close to each other. After the thermal stimulus, both films present a complicated response composed of an initial shrinkage, followed by a rearrangement. Interestingly, a subsequent reswelling of the collapsed film is only observed in the case of having applied a thermal stimulus of 20 to 40 °C. The normalized film thickness and the D2O amount of each layer in the PMEO2MA-b-POEGMA300 films are consistent at the end of the two different thermal stimuli. Hence, it can be concluded that the thermal history does not influence the final state of the PMEO2MA-b-POEGMA300 films upon heating. Based on this property, these thin films are especially suitable for the temperature switches on the nanoscale, which may experience different thermal histories.

In vivo elongation of thin filaments results in heart failure.

A novel cardiac-specific transgenic mouse model was generated to identify the physiological consequences of elongated thin filaments during post-natal development in the heart. Remarkably, increasing the expression levels in vivo of just one sarcomeric protein, Lmod2, results in ~10% longer thin filaments (up to 26% longer in some individual sarcomeres) that produce up to 50% less contractile force. Increasing the levels of Lmod2 in vivo (Lmod2-TG) also allows us to probe the contribution of Lmod2 in the progression of cardiac myopathy because Lmod2-TG mice present with a unique cardiomyopathy involving enlarged atrial and ventricular lumens, increased heart mass, disorganized myofibrils and eventually, heart failure. Turning off of Lmod2 transgene expression at postnatal day 3 successfully prevents thin filament elongation, as well as gross morphological and functional disease progression. We show here that Lmod2 has an essential role in regulating cardiac contractile force and function.

Thermoresponsive Diblock Copolymer Films with a Linear Shrinkage Behavior and Its Potential Application in Temperature Sensors.

The linear shrinkage behavior in thermoresponsive diblock copolymer films and its potential application in temperature sensors are investigated. The copolymer is composed of two thermoresponsive blocks with different transition temperatures (TTs): di(ethylene glycol) methyl ether methacrylate (MEO2MA; TT1 = 25 °C) and poly(ethylene glycol) methyl ether methacrylate (OEGMA300; TT2 = 60 °C) with a molar ratio of 1:1. Aqueous solutions of PMEO2MA-b-POEGMA300 show a three-stage transition upon heating as seen with optical transmittance and small-angle X-ray scattering: dissolution (T < TT1), self-assembled micelles with core-shell structure (TT1 < T < TT2), and aggregation of collapsed micelles (T > TT2). Due to the restrictions in the polymer chain arrangement introduced by the solid Si substrate, spin-coated PMEO2MA-b-POEGMA300 films exhibit an entirely different internal structure and transition behavior. Neutron reflectivity shows the absence of an ordered structure normal to the Si substrate in as-prepared PMEO2MA-b-POEGMA300 films. After exposure to D2O vapor for 3 h and then increasing the temperature above its TT1 and TT2, the ordered structure is still not observed. Only a D2O enrichment layer is formed close to the hydrophilic Si substrate. Such PMEO2MA-b-POEGMA300 films show a linear shrinkage between TT1 and TT2 in a D2O vapor atmosphere. This special behavior can be attributed to the synergistic effect between the restrained collapse of the PMEO2MA blocks by the still swollen POEGMA300 blocks and the impedance of chain arrangement by the Si substrate. Based on this unique behavior, spin-coated PMEO2MA-b-POEGMA300 films are further prepared into a temperature sensor by implementing Ag electrodes. Its resistance decreases linearly with temperature between TT1 and TT2.

What's Next for Key and Core Tech?

The Universe is a complicated network that evolved out of the Big Bang to the human-dominated world we see today. Technology is a collection of natural or scientific phenomena that have been discovered and used by human beings. The combination and evolution of technology is forming a complex, self-organizing, and evolving scale-free network. Originating from a technological system, key and core technology is the cornerstone to boosting economic and social progress. To develop a more sustainably focused planet, key and core technologies will play an increasingly vital role.

Up-regulated MCPIP1 in abdominal aortic aneurysm is associated with vascular smooth muscle cell apoptosis and MMPs production.

Abdominal aortic aneurysm (AAA) is often clinically silent before rupture characterized by extensive vascular inflammation and degenerative elasticity of aortic wall. Monocyte chemotactic protein-induced protein-1 (MCPIP1) exhibits anti-infllammatory and pro-apoptotic effects involved in atherogenesis. However, little is known about the expression and the contribution of MCPIP1 in AAA. In the present study, we collected clinical AAA specimens and constructed AAA mice model through Ang-II infusion, and found apparently increased MCPIP1 expression and severe inflammatory infiltration in AAA aortic membrane as evidenced by elevated levels of monocyte chemotactic protein 1 (MCP-1), interleukin 1 ß (IL-1ß) and NF-κB, as well as HE staining. The elasticity of aortic tunica media was impaired along with multiple apoptosis of vascular smooth muscle cells (VSMCs) in Ang-II-induced aneurysmal mouse. In vitro Ang-II administration of VSMCs induced MCPIP1 expression, accompanied by up-regulation of matrix metalloproteinase (MMP) 2 (MMP-2) and MMP-9, as well as enhancement of VSMCs proliferation and apoptosis, which may cause damage of intima-media elasticity. Silencing MCPIP1 reversed above effects to further restore the balance of proliferation and apoptosis in VSMCs. Overall, our data indicated that up-regulation of MCPIP1 may become a promising candidate for the diagnosis of AAA, and specific knockdown of MCPIP1 in VSMCs could inhibit VSMCs apoptosis and down-regulate MMPs to maintain vascular wall elasticity. Therefore, knockdown of MCPIP1 may serve as a potential target for gene therapy of AAA.

ACSS2/AMPK/PCNA pathway­driven proliferation and chemoresistance of esophageal squamous carcinoma cells under nutrient stress.

Although platinum­based chemotherapy is the first­line choice for locally advanced or metastatic esophageal squamous cell carcinoma (ESCC) patients, accelerated recurrence and chemoresistance remain inevitable. New evidence suggests that metabolism reprogramming under stress involves independent processes that are executed with a variety of proteins. This study investigated the functions of nutrient stress (NS)­mediated acetyl­CoA synthetase short­chain family member 2 (ACSS2) in cell proliferation and cisplatin­resistance and examined its combined effects with proliferating cell nuclear antigen (PCNA), a key regulator of DNA replication and repair. Here, it was demonstrated that under NS, when the AMP­activated protein kinase (AMPK) pathway was activated, ESCC cells maintained proliferation and chemoresistance was distinctly upregulated as determined by CCK­8 assay. As determined using immunoblotting and RT­qPCR, compared with normal esophageal epithelial cells (Het­1A), ESCC cells were less sensitive to NS and showed increased intracellular levels of ACSS2. Moreover, it was shown that ACSS2 inhibition by siRNA not only greatly interfered with proliferation under NS but also participated in DNA repair after cisplatin treatment via PCNA suppression, and the acceleration of cell death was dependent on the activation of the AMPK pathway as revealed by the Annexin V/PI and TUNEL assay results. Our study identified crosstalk between nutrient supply and chemoresistance that could be exploited therapeutically to target AMPK signaling, and the results suggest ACSS2 as a potential biomarker for identifying higher­risk patients.

Metformin represses the pathophysiology of AAA by suppressing the activation of PI3K/AKT/mTOR/autophagy pathway in ApoE-/- mice.

BACKGROUND: The protective effect of metformin (MET) on abdominal aortic aneurysm (AAA) has been reported. However, the related mechanism is still poor understood. In this study, we deeply investigated the role of metformin in AAA pathophysiology. METHODS: Angiotensin II (Ang-II) was used to construct the AAA model in ApoE -/- mice. The related mechanism was explored using Western blot and quantitative real time PCR (qRT-PCR). We also observed the morphological changes in the abdominal aorta and the influence of metformin on biological behaviors of rat abdominal aortic VSMCs. RESULTS: The PI3K/AKT/mTOR pathway was activated in aneurysmal wall tissues of AAA patients and rat model. Treatment with metformin inhibited the breakage and preserved the elastin structure of the aorta, the loss of collagen, and the apoptosis of aortic cells. In addition, metformin significantly suppressed the activation of the PI3K/AKT/mToR pathway and decreased the mRNA and protein levels of LC3B and Beclin1, which were induced by Ang-II. Moreover, PI3K inhibitors enhanced the effect of metformin while PI3K agonists largely reversed this effect. Interestingly, the cell proliferation, apoptosis, migration and autophagy of vascular smooth muscle cells (VSMCs) induced by Ang-II were also decreased following metformin treatment. PI3K inhibitors and agonists strengthened and weakened the effects of metformin in VSMCs, respectively. CONCLUSIONS: Metformin represses the pathophysiology of AAA by inhibiting the activation of PI3K/AKT/mTOR/autophagy pathway. This repression may be useful as a new therapeutic strategy for AAA.