Recent advances in graphene-family nanomaterials for effective drug delivery and phototherapy

INTRODUCTION

Owing to the unique properties of graphene, including large specific surface area, excellent thermal conductivity, and optical absorption, graphene-family nanomaterials (GFNs) have attracted extensive attention in biomedical applications, particularly in drug delivery and phototherapy.

AREAS COVERED

In this review, we point out several challenges involved in the clinical application of GFNs. Then, we provide an overview of the most recent publications about GFNs in biomedical applications, including diverse strategies for improving the biocompatibility, specific targeting and stimuli-responsiveness of GFNs for drug delivery, codelivery of drug and gene, photothermal therapy, photodynamic therapy, and multimodal combination therapy.

EXPERT OPINION

Although the application of GFNs is still in the preclinical stage, rational modification of GFNs with functional elements or making full use of GFNs-based multimodal combination therapy might show great potential in biomedicine for clinical application.

[Autophagy in the liver failure]

Liver failure is a severe liver disease syndrome, with massive or sub-massive liver tissues necrosis, and it develops rapidly, with poor clinical prognosis and high mortality. In recent years, autophagy role in the liver failure has received increasing attention. The study of the role of regulatory mechanism of autophagy is of great significance for the in-depth study of the prevention and treatment of liver failure. Based on the research progress of liver failure at home and abroad, this paper explores and summarizes the relationship between autophagy with necrosis and apoptosis, as well as the mechanism and expression level of autophagy in each stage of liver failure, with hope to provide reference for the in-depth research and clinical treatment of liver failure.

[Cardiovascular disease risk in diabetes patients aged 40 years old and above in China]

Objective: To evaluate the incidence of cardiovascular disease (CVD), ischemic and hemorrhagic cardiovascular events among Chinese diabetic patients aged 40 years and above with different CVD risk levels. Methods: This study enrolled participants aged 40 years and above in 15 provinces from a prospective cohort study, the China-PAR project (Prediction for Atherosclerotic Cardiovascular Disease Risk in China). Participants were categorized into two groups according to the presence or absence of diabetes at baseline. Individuals were further classified into low (0-4.9%), moderate (5%-9.9%) and high risk groups (≥10%), based on predicted ten-year CVD risk using the China-PAR equations. Two followed-up surveys were conducted between 2007 and 2015 to identify CVD events, which were defined as nonfatal acute myocardial infarction, or death due to coronary heart disease, or stroke. Ischemic cardiovascular events included nonfatal acute myocardial infarction, or death due to coronary heart disease, or ischemic stroke. Hemorrhagic cardiovascular events included subarachnoid hemorrhage and intracerebral hemorrhage. The incidences of CVD, ischemic and hemorrhagic cardiovascular events were compared in diabetes and non-diabetes population with different CVD risk levels. Results: This study included 89 209 participants aged 40 years and above, the average follow-up period was 8.5 years. The age was (54.8±9.4) years, and 36 794 (41.2%) were men, and 5 730 (6.4%) were diabetic patients. In diabetes patients aged 40 years and above, 53.7% (3 075/5 730) were at high risk of CVD. Age-and sex-adjusted incidence of CVD, ischemic and hemorrhagic cardiovascular events (1 066.93/100 000 person-years, 824.23/100 000 person-years, and 211.56/100 000 person-years) were significantly lower in diabetes patients than those in non-diabetes population with high CVD risk (1 773.73/100 000 person-years, 1 228.18/100 000 person-years, and 446.49/100 000 person-years) (all P<0.001). Among high CVD risk populations, incidence of ischemic events was significantly higher in diabetic patients than in non-diabetes population (1 638.47/100 000 person-years vs. 1 228.18/100 000 person-years, P<0.001), but incidence of hemorrhagic events tended to be lower in diabetic patients than in non-diabetes population (415.70/100 000 person-years vs. 446.49/100 000 person-years, P=0.635). Incidence of ischemic and hemorrhagic events were similar between diabetes patients and non-diabetes population at low or moderate CVD risk groups (all P>0.05). Conclusions: More than half of diabetes patients aged 40 years and above in China have high CVD risk. The incidence of CVD, ischemic and hemorrhagic cardiovascular events are different in diabetic patients with different CVD risk levels.

Peroxisome proliferator-activated receptor gamma in white and brown adipocyte regulation and differentiation

In as early as 1997, the World Health Organization officially recognized obesity as a chronic disease. The current epidemic of obesity and overweightness has aroused great interest in the study of adipose tissue formation. The transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) binds to the target gene promoter regulatory sequences, acting as a key factor in regulating the differentiation of preadipocytes in the adipose tissue, and plays an important role in regulating the adipocyte metabolism. A further understanding of the structure and expression characteristics of PPARgamma, in addition to its mechanisms of action in adipocyte differentiation, may be applied to control obesity and prevent obesity-related diseases. In this article, recent studies investigating the effect of regulating PPARgamma on adipocyte differentiation are reviewed. In particular, the structural characteristics, expression patterns, and molecular mechanisms of PPARgamma function in adipocyte differentiation are considered.

In vitro immunomodulatory effects of thymol and cinnamaldehyde in a pig intestinal epithelial cell line (IPEC-J2)

Thymol and cinnamaldehyde are phytogenic feed additives developed to improve gut health and growth performance in poultry and swine. This study evaluated the in vitro immune modulating effects of thymol and cinnamaldehyde blend (TCB) in a porcine gut epithelial cell line (IPEC-J2), with or without cellular damage caused by challenge with lipopolysaccharides. Cytotoxicity, permeability, wound-healing and bacteria adhesion assays were recorded. The expression of cytokines, tight junctions and polymeric immunoglobulin receptor (pIgR) were measured by RT-PCR. The IPEC-J2 cells were cultured in the presence of TCB at concentrations ranging from 1 ng/ml to 1 μg/ml and displayed high viability (>90%). TCB increased barrier integrity (13.8% less in lipopolysaccharide challenge which induced gut epithelial leakage, P<0.05) and accelerated the initial speed of wound recovery (day 1, 26% wound recovery in TCB treated vs 7% in control, P<0.05; day 2, 54 vs 39%, P<0.001). The RT-PCR analysis of cell culture showed that TCB upregulated anti-inflammatory cytokine interleukin (IL)-10 (73.3%, P<0.05) in non-stimulated IPEC-J2 cells, while, when stimulated, pIgR (9.7%, P<0.05) and tight junctions claudin-4 (9.4%, P<0.05) were upregulated by TCB. Furthermore, TCB significantly increased Lactobacillus acidophilus adherence to gut epithelial cells (285.0%, P<0.05). Overall, the current in vitro study showed that TCB can induce various immune responses, which may explain its in vivo benefits as feed additive.

[Liver failure and glucocorticoid resistance]

The main pathogenesis of liver failure is immune damage and uncontrolled inflammatory response. Glucocorticoids have strong immunosuppressive and anti-inflammatory effects, and are considered to be useful for the treatment of liver failure. However, the results of many clinical studies have shown that the application of glucocorticoids in patients with liver failure cannot effectively improve the prognosis, but instead increases the chance of infection and endangers life. Provided that, it seems reasonable to assume that glucocorticoid resistance exists in patients with liver failure. This article analyzes the mechanism by which P-glycoprotein reverses glucocorticoid transport, intracellular glucocorticoid signaling pathway dysfunction and related gene mutations when the inflammatory response is uncontrolled. In addition, we also evaluated the sensitivity of glucocorticoids in patients with liver failure, so as to provide theoretical basis for efficacy and medication timing.

LncRNA TATDN1 induces the progression of hepatocellular carcinoma via targeting miRNA-6089

OBJECTIVE

To clarify the potential effect of long non-coding RNA (lncRNA) TATDN1 on accelerating the proliferative rate and cell cycle progression of hepatocellular carcinoma (HCC) via sponging miRNA-6089, thus participating in the progression of HCC.

PATIENTS AND METHODS

TATDN1 expression in HCC tissues and normal tissues was first determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The correlation between TATDN1 expression to metastasis and overall survival of HCC was analyzed. The cellular level of TATDN1 in HCC cell lines was examined as well. Regulatory effects of TATDN1 on cell cycle progression and viability of HepG2 and SMMC7721 cells were evaluated. Subsequently, a potential target of TATDN1 was screened out and verified by Dual-Luciferase reporter gene assay. The expression pattern and biological function of the target gene miRNA-6089 in HCC were also determined. In a similar way, LIX1L was verified to be the target of miRNA-6089 and tested for its biological function in HCC.

RESULTS

TATDN1 was upregulated in HCC tissues and cell lines. The overexpression of TATDN1 accelerated the proliferative rate and cell cycle progression of HCC. MiRNA-6089, the target gene of TATDN1, was lowly expressed in HCC. The overexpression of miRNA-6089 partially reversed the promotive role of TATDN1 in regulating the proliferation and cell cycle of HCC cells. Subsequently, LIX1L was verified to be the target of miRNA-6089. The overexpression of LIX1L partially reversed the regulatory effect of miRNA-6089 on the proliferative rate and cell cycle progression of HCC.

CONCLUSIONS

TATDN1 accelerates the proliferative rate and cell cycle progression of HCC by degrading miRNA-6089 to upregulate LIX1L.

MicroRNA-126 affects cell apoptosis, proliferation, cell cycle and modulates VEGF/TGF-β levels in pulmonary artery endothelial cells

OBJECTIVE

In the clinic, therapeutic options for pulmonary arterial hypertension are limited; therefore, investigating the therapeutic strategies and novel therapies is critical for pulmonary arterial hypertension (PAH) treatment. This study aimed to evaluate the role of miRNA-126 (miR-126) and its associated signaling pathways and specific mechanisms for the pathogenesis of PAH.

MATERIALS AND METHODS

The pulmonary artery endothelial cells (PAECs) were isolated and identified. The miR-126 mimic and miR-126 inhibitor were synthesized. LV-3-miR-126 mimic viral vector and LV-3-miR-126 inhibitor vector were established and infected into pulmonary artery endothelial cells. Expression of sprouty-related EVH1 domain-containing protein 1 (SPRED1), phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) and miR-126 were detected using Real-time PCR (RT-PCR). Cell apoptosis (Annexin V-PE/7-AAD) and proliferation (PKH26) were examined by using FACScan flow cytometry. Vascular endothelial growth factor (VEGF), transforming growth factor β1 (TGF-β1) and TGF-β3 levels were evaluated using enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

miR-126 inhibited the endothelial cells related to SPRED1 and PIK3R2 expression. Over-expression of miR-126 significantly inhibited the PAECs apoptosis compared to PAECs and blank LV-3 vector group (p<0.05). miR-126 significantly triggered the PAECs proliferation compared to PAECs and blank LV-3 vector group (p<0.05). In functional analysis, miR-126 mimic significantly increased the cells amounts of S phases compared to PAECs and blank LV-3 vector group (p<0.05). Pre-infection with miR-126 mimic significantly enhanced the levels of VEGF, TGF-β1, and TGF-β3 compared to PAECs and blank LV-3 vector group (p<0.05).

CONCLUSIONS

miR-126 could affect cell apoptosis, proliferation, cell cycle, and modulate VEGF/TGF-β levels.

[Pancreatoduodenectomy and non-alcoholic fatty liver disease]

Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological syndrome with similar hepatic histological changes to alcoholic liver disease, but without a history of excessive alcohol intake. Obesity, hyperlipidemia, diabetes, hypertension and other metabolic disorders are closely related to its occurrence and development, and its core mechanism is insulin resistance. In addition, there are also non-metabolic-related factors for the occurrence of non-alcoholic fatty liver disease, such as pancreatoduodenectomy. Pancreatoduodenectomy is the standard procedure for the treatment of tumor around the head of pancreas and ampulla. Postoperative pancreatic malfunction induced by pancreatic exocrine function after pancreatoduodenectomy is associated with the occurrence and development of secondary non-alcoholic fatty liver disease.

Immunomodulatory effects of thymol and cinnamaldehyde in chicken cell lines

Thymol and cinnamaldehyde are phytogenic feed additives that have been developed to improve gut health, immunity and growth performance in poultry and swine. This study evaluated the immune modulating effects of a thymol and cinnamaldehyde blend (TCB) in the intestinal system of poultry in vitro, using two chicken cell lines, LMH (liver cell line) which has been used to mimic epithelial cell responses, and HD-11 (monocyte/macrophage-like). Cells with high viability (>95%) from established cell lines were cultured in the presence of TCB at concentrations ranging from 1 ng/ml to 100 ng/ml. The viability, transepithelial electrical resistance (TEER) and phagocytic capacity of co-cultured LMH cells, with or without stimulation with lipopolysaccharide (LPS), was subsequently evaluated. The expression of cytokines, chemokines and pattern recognition receptors by HD-11 monocytes/macrophages was measured by RT-PCR and by proteomic analysis. TCB was well tolerated by both cell lines (cell viability >90% after co-culture with TCB at 100 ng/ml for 48 h with or without LPS). Epithelial integrity of LMH cells (as assessed by TEER) was increased by TCB (10 ng/ml) after 4 h incubation, versus untreated controls, and phagocytic capacity of HD-11 cells was increased, in a dose-dependent manner (P<0.05). In HD-11 cells, TCB (10 ng/ml) downregulated the relative expression of pro-inflammatory cytokines interleukin (IL)-1β, IL-6, IL-8 and the transcription factor cyclooxygenase-2 and upregulated expression of anti-inflammatory IL-10, versus untreated controls (P<0.05). In summary, under the tested conditions, TCB enhanced the epithelial barrier integrity of poultry hepatocytes, increased phagocytic activity and production of anti-inflammatory cytokines by monocytes and macrophages. These results indicated how supplementing TCB in poultry diets can increase bird performance, by increasing in vivo cell membrane integrity (especially important in the gut) and assisting in immune responses, which can liberate energy for growth.

Direct investigation of current transport in cells by conductive atomic force microscopy

Currents play critical roles in neurons. Direct observation of current flows in cells at nanometre dimensions and picoampere current resolution is still a daunting task. In this study, we investigated the current flows in hippocampal neurons, PC12 cells and astrocytes in response to voltages applied to the cell membranes using conductive atomic force microscopy (CAFM). The spines in the hippocampal neurons play crucial roles in nerve signal transfer. When the applied voltage was greater than 7.2 V, PC12 cells even show metallic nanowire-like characteristics. Both the cell body and glial filaments of astrocytes yielded CAFM test results that reflect different electrical conductance. To our best knowledge, the electrical characteristics and current transport through components of cells (especially neurons) in response to an applied external voltage have been revealed for the first time at nanometre dimensions and picoampere current levels. We believe that such studies will pave new ways to study and model the electrical characteristics and physiological behaviours in cells and other biological samples.

Reestablishment of Social Hierarchies in Weaned Pigs after Mixing

Pigs are animals that live in groups and have social hierarchies within the group. After mixing, they can re-establish social hierarchies within several days through fighting. Dominance hierarchical indices, such as I&SI, Elo rating, and Glicko rating, have been used to analyze social hierarchies of some social animals but not pigs. I&SI index involves iterative calculations that first minimize the number of inconsistencies (I) in a dominance matrix, and then minimize the strength of those inconsistencies (SI). Elo rating and Glicko rating indices are based on the sequence in which interactions occur, and continuously update ratings by looking at interactions sequentially. To study the temporal dynamics of social hierarchy formation and maintenance in weaned pigs after mixing, a total of 102 pigs (47 females and 55 barrows) were selected by similar body weight and mixed in 10 pens (10 or 11 females or barrows per pen). Their behavior was recorded and observed for 72 h after mixing. Results showed that hierarchical indices I&SI, Elo rating, and Glicko rating were associated with each other (|r| = 0.681 ~ 0.942, p < 0.001). I&SI was associated with logarithms of frequency of active attack (|r| = 0.65, p < 0.05) and tended to associated with logarithms of frequency of standoff (|r| = 0.48, p < 0.1). Elo rating, and Glicko rating were associated with the logarithms of duration of being bullied (|r| = 0.393~0.401, p < 0.05). In addition, Glicko rating tended to be associated with the logarithms of duration of active attack and frequency of active attack (|r| = 0.416~0.439, p < 0.1). Multiple linear regression analyses of logarithms of dyadic behavior indicators for three hierarchical indices indicated the same effects. The time (hours) to achieve social stability of pigs after mixing was lower for females than barrows (23.06 ± 4.15 vs. 40.55 ± 4.71 h; p < 0.001). The most dominant pig (the first ranked) in each pen quickly appeared within a few hours after mixing and remained stable. Overall, our study demonstrated that the ranks calculated by the three dominance hierarchical indices: I&SI, Elo rating, and Glicko rating, were consistent and partially associated with part of the dyadic behavioral indicators in weaned pigs after mixing.