Sitagliptin inhibits EndMT in vitro and improves cardiac function of diabetic rats through the SDF-1α/PKA pathway

OBJECTIVE

The aim of this paper was to study sitagliptin in improving the endothelial-mesenchymal transition (EndMT) of human aortic endothelial cells (HAECs) and cardiac function of rats with diabetes mellitus (DM) and its possible pathway.

MATERIALS AND METHODS

Sprague Dawley (SD) rats were divided into control group, DM group and sitagliptin group. The myocardial contraction and relaxation functions of rats in each group were observed via echocardiography. The changes in cardiac structure and fiber were observed via hematoxylin-eosin (HE) staining, Masson staining and Sirius red staining. The immunohistochemical assay was performed to observe the expressions of α-smooth muscle actin (α-SMA) and VE-cadherin in HAECs; the expression of reactive oxygen species (ROS) in HAECs was detected using the fluorescence probe. Moreover, the expressions of transforming growth factor-β1 (TGF-β1), phosphorylated-protein kinase A (p-PKA), PKA and extracellular signal-regulated kinase (ERK) were observed via Western blotting.

RESULTS

Sitagliptin could improve the myocardial contraction and relaxation functions in diabetic rats and EndMT and ROS production in HAECs. In the DM group, the expression of Glucagon-like peptide-1 (GLP-1) was decreased, while the expression of stromal-derived factor-1α (SDF-1α) was decreased and the expressions of downstream PKA/ERK pathway and TGF-β1 were increased. The above changes could be reversed by sitagliptin.

CONCLUSIONS

Sitagliptin can reverse the EndMT in HAECs as well as the cardiac function in diabetic rats through the SDF-1α/PKA pathway.

Prevalence of dyslipidemia and associated risk factors among adults aged ≥35 years in northern China: a cross-sectional study

Background

Cardiovascular disease (CVD) prevalence has increased continuously over the last 30 years in China. Dyslipidemia is an important modifiable risk factor in CVD. We aimed to collect current data on the prevalence of dyslipidemia in northern China and explore potential influencing factors.

Methods

In this cross-sectional study, we selected a representative sample of 65,128 participants aged ≥35 years in Inner Mongolia during 2015–2017. All participants completed a questionnaire and were examined for risk factors. Dyslipidemia was defined according to 2016 Chinese guidelines for adults. The associated factors for dyslipidemia were estimated by multivariate logistic regression analysis.

Results

The age-standardized prevalence of dyslipidemia was 31.2% overall, with 4.3, 2.4, 14.7, and 17.4% for high total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and low high-density lipoprotein cholesterol (HDL-C), respectively. The dyslipidemia prevalence was significantly higher in men than women (37.9% vs. 27.5%, P < 0.001), but postmenopausal women had a higher prevalence of dyslipidemia components (except low HDL-C). Compared with Han participants, Mongol participants had a lower prevalence of dyslipidemia (29.1% vs. 31.4%, P < 0.001). Male sex, living in urban areas, Han ethnicity, smoking, obesity, central obesity, hypertension, and diabetes were all positively correlated with dyslipidemia; alcohol consumption was linked to lower risk of dyslipidemia.

Conclusions

Our study revealed that dyslipidemia is a health problem in northern China. Greater efforts to prevent and manage dyslipidemia, especially in men under age 55 years, postmenopausal women, and people with unhealthy lifestyles or chronic diseases.

Assessment of cardiovascular disease risk in Northern China: a cross-sectional study

Cardiovascular disease (CVD) is a life-threatening chronic illness. CVD risk may be influenced by environment and lifestyle. People in northern China usually consume high-fat, high-salt diets and alcohol and live in a cold climate over long periods. However, there are limited studies on CVD risk among people in northern China. In the present study, we sought to estimate the CVD risk profile among residents of northern China. Using the Programme of Screening and Intervention Subjects with High Risk Cardiovascular Diseases, we collected data from residents in six cities from September 2015 to June 2017. In total, 56,716 participants aged 40 years and above were finally included in the CVD risk assessment. To assess the 10-year risk of CVD among participants, we used World Health Organisation/International Society of Hypertension risk prediction charts. Among the study participants, 22.7% had a high 10-year risk of CVD. We identified differences in the 10-year CVD risk according to sex, socioeconomic status, and marital status. We conclude that individuals with high socioeconomic status should be encouraged to change their lifestyle habits, and greater medical resources should be invested for individuals residing in rural areas and those with low education levels.

Spin squeezing of 1011 atoms by prediction and retrodiction measurements

The measurement sensitivity of quantum probes using N uncorrelated particles is restricted by the standard quantum limit¹, which is proportional to [Formula: see text]. This limit, however, can be overcome by exploiting quantum entangled states, such as spin-squeezed states². Here we report the measurement-based generation of a quantum state that exceeds the standard quantum limit for probing the collective spin of 10¹¹ rubidium atoms contained in a macroscopic vapour cell. The state is prepared and verified by sequences of stroboscopic quantum non-demolition (QND) measurements. We then apply the theory of past quantum states^3,4 to obtain spin state information from the outcomes of both earlier and later QND measurements. Rather than establishing a physically squeezed state in the laboratory, the past quantum state represents the combined system information from these prediction and retrodiction measurements. This information is equivalent to a noise reduction of 5.6 decibels and a metrologically relevant squeezing of 4.5 decibels relative to the coherent spin state. The past quantum state yields tighter constraints on the spin component than those obtained by conventional QND measurements. Our measurement uses 1,000 times more atoms than previous squeezing experiments^5-10, with a corresponding angular variance of the squeezed collective spin of 4.6 × 10^-13 radians squared. Although this work is rooted in the foundational theory of quantum measurements, it may find practical use in quantum metrology and quantum parameter estimation, as we demonstrate by applying our protocol to quantum enhanced atomic magnetometry.

Platelet-derived microvesicles promote endothelial progenitor cell proliferation in intimal injury by delivering TGF-β1

Intimal injury is an early stage of several cardiovascular diseases. Endothelial progenitor cells (EPCs) play a significant role in endothelial repair following vascular injury. Once the intima is damaged, EPCs are mobilized from the bone marrow to the injury site. Meanwhile, the injury to the intimal surface triggers platelet degranulation, aggregation, and adhesion to the damaged endothelium, and exposed collagen stimulates platelet to secrete platelet-derived microvesicles (PMVs). However, the role of PMVs in EPC function during this process remains unknown. In an in vivo study, EPCs and platelets were found to adhere to the injury site in Sprague-Dawley (SD) rat vascular injury model. In vitro, collagen stimulation induced the release of PMVs, and collagen-activated PMVs (ac.PMVs) significantly promoted EPC proliferation. Transforming growth factor-β1 (TGF-β1) content was increased in ac.PMVs. Activated PMVs significantly upregulated Smad3 phosphorylation in EPCs and increased Smad3 nuclear translocation from the cytoplasm. TGF-β1 knockdown ac.PMVs downregulated EPC proliferation. Recombinant TGF-β1 enhanced EPC proliferation. The TGF-β1 inhibitor SB431542 significantly repressed the intracellular signal triggered by ac.PMVs. Furthermore, the Smad3-specific phosphorylation inhibitor SIS3 effectively reversed the cell proliferation induced by ac.PMVs. Smad3 translocated to the nucleus and enhanced EPC proliferation via its downstream genes tenascin C (TNC), CDKN1A, and CDKN2A. r-TGF-β1 promoted reendothelialization and EPC proliferation in vivo. Our data demonstrate that activated PMVs deliver TGF-β1 from collagen-activated platelets to EPCs, which in turn activates Smad3 phosphorylation and regulates TNC, CDKN1A, and CDKN2A expression to promote EPC proliferation, suggesting that PMVs act as a key transporter and a potential therapeutic target for vascular injury.

Lamin A/C negatively regulated by miR-124-3p modulates apoptosis of vascular smooth muscle cells during cyclic stretch application in rats

AIM

Apoptosis of vascular smooth muscle cells (VSMCs) influenced by abnormal cyclic stretch is crucial for vascular remodelling during hypertension. Lamin A/C, a nuclear envelope protein, is mechano-responsive, but the role of lamin A/C in VSMC apoptosis is still unclear.

METHODS

FX-5000T Strain Unit provided cyclic stretch (CS) in vitro. AnnexinV/PI and cleaved Caspase 3 ELISA detected apoptosis. qPCR was used to investigate the expression of miR-124-3p and a luciferase reporter assay was used to evaluate the ability of miR-124-3p binding to the Lmna 3'UTR. Protein changes of lamin A/C and relevant molecules were detected using western blot. Ingenuity Pathway Analysis and Protein/DNA array detected the potential transcription factors. Renal hypertensive rats verified these changes.

RESULTS

High cyclic stretch (15%-CS) induced VSMC apoptosis and repressed lamin A/C expressions compared with normal (5%-CS) control. Downregulation of lamin A/C enhanced VSMC apoptosis. In addition, 15%-CS had no significant effect on mRNA expression of Lmna, and lamin A/C degradation was not induced by autophagy. 15%-CS elevated miR-124-3p bound to the 3'UTR of Lmna and negatively regulated protein expression of lamin A/C. Similar changes occurred in renal hypertensive rats compared with sham controls. Lamin A/C repression affected activity of TP53, CREB1, MYC, STAT1/5/6 and JUN, which may in turn affect apoptosis.

CONCLUSION

Our data suggested that the decreased expression of lamin A/C upon abnormal cyclic stretch and hypertension may induce VSMC apoptosis. These mechano-responsive factors play important roles in VSMC apoptosis and might be novel therapeutic targets for vascular remodelling in hypertension.

Comparative ultrafast spectroscopy and structural analysis of OCP1 and OCP2 from Tolypothrix

The orange carotenoid protein (OCP) is a structurally and functionally modular photoactive protein involved in cyanobacterial photoprotection. Recently, based on bioinformatic analysis and phylogenetic relationships, new families of OCP have been described, OCP2 and OCPx. The first characterization of the OCP2 showed both faster photoconversion and back-conversion, and lower fluorescence quenching of phycobilisomes relative to the well-characterized OCP1. Moreover, OCP2 is not regulated by the fluorescence recovery protein (FRP). In this work, we present a comprehensive study combining ultrafast spectroscopy and structural analysis to compare the photoactivation mechanisms of OCP1 and OCP2 from Tolypothrix PCC 7601. We show that despite significant differences in their functional characteristics, the spectroscopic properties of OCP1 and OCP2 are comparable. This indicates that the OCP functionality is not directly related to the spectroscopic properties of the bound carotenoid. In addition, the structural analysis by X-ray footprinting reveals that, overall, OCP1 and OCP2 have grossly the same photoactivation mechanism. However, the OCP2 is less reactive to radiolytic labeling, suggesting that the protein is less flexible than OCP1. This observation could explain fast photoconversion of OCP2.

Hidden Bursting Firings and Bifurcation Mechanisms in Memristive Neuron Model With Threshold Electromagnetic Induction

Memristors can be employed to mimic biological neural synapses or to describe electromagnetic induction effects. To exhibit the threshold effect of electromagnetic induction, this paper presents a threshold flux-controlled memristor and examines its frequency-dependent pinched hysteresis loops. Using an electromagnetic induction current generated by the threshold memristor to replace the external current in 2-D Hindmarsh-Rose (HR) neuron model, a 3-D memristive HR (mHR) neuron model with global hidden oscillations is established and the corresponding numerical simulations are performed. It is found that due to no equilibrium point, the obtained mHR neuron model always operates in hidden bursting firing patterns, including coexisting hidden bursting firing patterns with bistability also. In addition, the model exhibits complex dynamics of the actual neuron electrical activities, which acts like the 3-D HR neuron model, indicating its feasibility. In particular, by constructing the fold and Hopf bifurcation sets of the fast-scale subsystem, the bifurcation mechanisms of hidden bursting firings are expounded. Finally, circuit experiments on hardware breadboards are deployed and the captured results well match with the numerical results, validating the physical mechanism of biological neuron and the reliability of electronic neuron.

Endothelial microvesicles induced by physiological cyclic stretch inhibit ICAM1-Dependent leukocyte adhesion

Physiological cyclic stretch (CS), caused by artery deformation following blood pressure, plays important roles in the homeostasis of endothelial cells (ECs). Here, we detected the effect of physiological CS on endothelial microvesicles (EMVs) and their roles in leukocyte recruitment to ECs, which is a crucial event in EC inflammation. The results showed compared with the static treatment, pretreatment of 5%-CS-derived EMVs with ECs significantly decreased the adherence level of leukocytes. Comparative proteomic analysis revealed 373 proteins differentially expressed between static-derived and 5%-CS-derived EMVs, in which 314 proteins were uniquely identified in static-derived EMVs, 34 proteins uniquely in 5%-CS-derived EMVs, and 25 proteins showed obvious differences. Based on the proteomic data, Ingenuity Pathways Analysis predicted intercellular adhesion molecule 1 (ICAM1) in EMVs might be the potential molecule involved in EC-leukocyte adhesion. Western blot and flow cytometry analyses confirmed the significant decrease of ICAM1 in 5%-CS-derived EMVs, which subsequently inhibited the phosphorylation of VE-cadherin at Tyr731 in target ECs. Moreover, leukocyte adhesion was obviously decreased after pretreatment with ICAM1 neutralizing antibody. Our present research suggested that physiological stretch changes the components of EMVs, which in turn inhibits leukocyte adhesion. ICAM1 expressed on CS-induced EMVs may play an important role in maintaining EC homeostasis.

Co-delivery of epirubicin and paclitaxel using an estrone-targeted PEGylated liposomal nanoparticle for breast cancer

Breast cancer is one of the most frequent malignancies in the female population. Recently, the development of medical products has been advanced for this disease; however, patients still suffer from the failure of current treatments and new therapeutic strategies are urgently required. In this study, due to the overexpression of the estrogen receptor (ER) in breast cancer and the ability of ER to specifically bind to its ligand estrone (ES), an ES-targeted PEGylated epirubicin (EPI) and paclitaxel (PTX) co-loaded liposomal nanoparticle (NP) (termed as ES-SSL-EPI/PTX) was developed. Physicochemical studies demonstrated that the ES-SSL-EPI/PTX had a nanoscaled particle size (~120 nm) and a neutral zeta potential (~-5 mV) and presented favorable stability in physiological media. In vitro, the ES-SSL-EPI/PTX showed a significantly higher cellular uptake in human breast cancer MCF-7 cells mainly via the receptor-ligand mediated pathway resulting in effective cytotoxic activity. In vivo targeting study, the accumulation of targeted liposomes in tumor was significantly improved. The systemic circulation time and biodistribution in main organs of EPI and PTX delivered by ES-SSL-Liposomes were increased. Consequently, the ES-SSL-EPI/PTX significantly suppressed tumor growth in the MCF-7-derived tumor-bearing mouse model without inducing toxicity. These results suggested that the ES-SSL-EPI/PTX was a promising formulation for co-delivery of chemotherapeutics in the treatment of breast cancer.

Rare variants in MYH15 modify amyotrophic lateral sclerosis risk

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by progressive muscular atrophy and respiratory failure. The G4C2 repeat expansion in the C9orf72 gene is the most prevalent genetic risk for ALS. Mutation carriers (C9ALS) display variability in phenotypes such as age-at-onset and duration, suggesting the existence of additional genetic factors. Here we introduce a three-step gene discovery strategy to identify genetic factors modifying the risk of both C9ALS and sporadic ALS (sALS) using limited samples. We first identified 135 candidate genetic modifiers of C9ALS using whole-genome sequencing (WGS) of extreme C9ALS cases diagnosed ~30 years apart. We then performed an unbiased genetic screen using a Drosophila model of the G4C2 repeat expansion with the genes identified from WGS analysis. This genetic screen identified the novel genetic interaction between G4C2 repeat-associated toxicity and 18 genetic factors, suggesting their potential association with C9ALS risk. We went on to test if 14 out of the 18 genes, those which were not known to be risk factors for ALS previously, are also associated with ALS risk in sALS cases. Gene-based-statistical analyses of targeted resequencing and WGS were performed. These analyses together reveal that rare variants in MYH15 represent a likely genetic risk factor for ALS. Furthermore, we show that MYH15 could modulate the toxicity of dipeptides produced from expanded G4C2 repeat. Our study presented here demonstrates the power of combining WGS with fly genetics to facilitate the discovery of fundamental genetic components of complex traits with a limited number of samples.

Effects of occupation on intracerebral hemorrhage-related deaths in Inner Mongolia

This study assessed the relationship between occupation and Intracerebral Hemorrhage-related deaths and compared the differences in ICH-related deaths rates between the eastern and midwestern regions of Inner Mongolia. We used the case-control method. Cases included Intracerebral Hemorrhage-related deaths that occurred from 2009 to 2012 in Inner Mongolia while controls included non-circulatory system disease deaths that occurred during the same period. Odds ratios (ORs) for Intracerebral Hemorrhage-related deaths were calculated using logistic regression analysis, estimated according to occupation, and adjusted for marital status and age. The Intracerebral Hemorrhage mortality rate in the eastern regions (125.19/100000) was nearly 3 times higher than that in the midwestern regions (45.31/100000). ORs for agriculture-livestock workers, service professionals and general workers, professional workers and senior officials were in descending order. The age-adjusted OR for Intracerebral Hemorrhage-related deaths was lowest in unmarried men senior officials (OR 0.37, 95% CI 0.14-0.99). The Intracerebral Hemorrhage mortality rate in the eastern regions was much higher than that of the midwestern regions, since about 90% of Intracerebral Hemorrhage-related deaths in the eastern regions were those of agriculture-livestock workers who has the largest labor intensity of any other occupation assessed.

X-ray radiolytic labeling reveals the molecular basis of orange carotenoid protein photoprotection and its interactions with fluorescence recovery protein

In cyanobacterial photoprotection, the orange carotenoid protein (OCP) is photoactivated under excess light conditions and binds to the light-harvesting antenna, triggering the dissipation of captured light energy. In low light, the OCP relaxes to the native state, a process that is accelerated in the presence of fluorescence recovery protein (FRP). Despite the importance of the OCP in photoprotection, the precise mechanism of photoactivation by this protein is not well-understood. Using time-resolved X-ray-mediated in situ hydroxyl radical labeling, we probed real-time solvent accessibility (SA) changes at key OCP residues during photoactivation and relaxation. We observed a biphasic photoactivation process in which carotenoid migration preceded domain dissociation. We also observed a multiphasic relaxation process, with collapsed domain association preceding the final conformational rearrangement of the carotenoid. Using steady-state hydroxyl radical labeling, we identified sites of interaction between the FRP and OCP. In combination, the findings in this study provide molecular-level insights into the factors driving structural changes during OCP-mediated photoprotection in cyanobacteria, and furnish a basis for understanding the physiological relevance of the FRP-mediated relaxation process.

Management and population dynamics of diamondback moth (Plutella xylostella): planting regimes, crop hygiene, biological control and timing of interventions

Using an age-structured process-based simulation model for diamondback moth (DBM), we model the population dynamics of this major Brassica pest using the cropping practices and climate of Guangdong, China. The model simulates two interacting sub-populations (demes), each representing a short season crop. The simulated DBM abundance, and hence pest problems, depend on planting regime, crop hygiene and biological control. A continuous supply of hosts, a low proportion of crop harvested and long residue times between harvest and replanting each exacerbate pest levels. Biological control provided by a larval parasitoid can reduce pest problems, but not eliminate them when climate is suitable for DBM and under certain planting practices. The classic Integrated Pest Management (IPM) method of insecticide application, when pest threshold is reached, proved effective and halved the number of insecticide sprays when compared with the typical practice of weekly insecticide application.