Effects of arachidonic acid and its major prostaglandin derivatives on bovine myoblast proliferation, differentiation, and fusion

Many studies have shown positive effects of prostaglandins (PGs) on various steps of skeletal muscle formation such as myoblast proliferation and myotube hypertrophy. In animals, PGs are synthesized through the action of the rate-limiting enzymes cyclooxygenase (COX) -1 and COX-2 from arachidonic acid (AA), a conditionally essential fatty acid. As a step toward exploring the possibility of using dietary supplementation of AA to improve skeletal muscle growth in cattle, which are major meat-producing animals, we determined the effects of AA and its major PG derivatives PGE₂, PGF_2α, and PGI₂ on proliferation, differentiation, and fusion of primary bovine myoblasts in vitro. In the proliferation experiment, myoblasts were cultured in a growth medium to which was added 10 μM AA, 1 μM PGE₂, 1 μM PGF_2α, 1 μM PGI₂, or vehicle control for 24 h, and the proliferating cells were identified by 5-ethynyl-2'-deoxyuridine (EdU) labeling. This experiment revealed that AA, PGE₂, PGF_2α, and PGI₂ each increased the number of proliferating cells by 13%, 24%, 16%, and 16%, respectively, compared to the control (n = 7, P < 0.05). In the differentiation and fusion test, myoblasts were induced to differentiate and fuse into myotubes in the presence of the aforementioned treatments for 0, 24, 48, and 72 h. Based on quantitative reverse transcription PCR analyses of mRNAs of myoblast differentiation and fusion markers (myogenin; myosin heavy chain 3; creatine kinase, muscle; myomaker) at 0, 24, and 48 h of differentiation, AA, PGE₂, and PGF_2α promoted myoblast differentiation (n = 6, P < 0.05). Based on Giemsa staining and counting the number of myotubes at 72 h of differentiation, PGE₂ enhanced the number of formed myotubes by 14% (P < 0.05) compared to the control. Treating the myoblasts with AA and either the COX-1 and COX-2 common inhibitor indomethacin or the COX-2-specific inhibitor NS-398 reversed the stimulatory effect of AA on myoblast proliferation (n = 4, P < 0.05). Overall, this study demonstrates that exogenous AA stimulates bovine myoblast proliferation and differentiation in culture. The results of this study suggest that AA stimulates myoblast proliferation through its metabolites PGE₂, PGF_2α, or PGI₂, and that AA stimulates myoblast differentiation through PGE₂.

The surrounding tissue contributes to smooth muscle cells’ regeneration and vascularization of small diameter vascular grafts

The surrounding tissue contributes to smooth muscle cells’ regeneration and vascularization in the vascular regeneration process.

A cell-penetrating peptide-assisted nanovaccine promotes antigen cross-presentation and anti-tumor immune response

Exogenous antigens processed in the cytosol and subsequently cross-presented on major histocompatibility complex class I (MHC-I) molecules activate cytotoxic CD8⁺ lymphocytes (CTL), which are crucial in cancer immunotherapy.

Dual pH/reduction-responsive hybrid polymeric micelles for targeted chemo-photothermal combination therapy

The combination of chemotherapy and photothermal therapy in multifunctional nanovesicles has emerged as a promising strategy to improve cancer therapeutic efficacy. Herein, we designed new pH/reduction dual-responsive and folate decorated polymeric micelles (FA Co-PMs) as theranostic nanocarrier to co-encapsulate doxorubicin (DOX) and indocyanine green (ICG) for targeted NIR imaging and chemo-photothermal combination therapy. The Co-PMs exhibited nano-sized structure (∼100 nm) with good monodispersity, high encapsulation efficiency of both ICG and DOX, triggered DOX release in response to acid pH and reduction environment, and excellent temperature conversion with laser irradiation. In vitro cellular uptake study indicated FA Co-PMs achieved significant targeting to BEL-7404 cells via folate receptor-mediated endocytosis, and laser-induced hyperthermia further enhanced drug accumulation into cancer cells. In vivo biodistribution study indicated that FA Co-PMs prolonged drug circulation and enhanced drug accumulation into the tumor via EPR effect and FA targeting. Furthermore, the ICG-based photo-triggered hyperthermia combined with DOX-based chemotherapy synergistically induced the BEL-7404 cell death and apoptosis, and efficiently suppressed the BEL-7404 xenografted tumor growth while significantly reduced systemic toxicity in vivo. Therefore, the designed dual-responsive Co-PMs were promising theranostic nanocarriers for versatile antitumor drug delivery and imaging-guided cancer chemo-photothermal combination therapy.

STATEMENT OF SIGNIFICANCE

The combination of chemotherapy and photothermal therapy in multifunctional nanovesicles has emerged as a promising strategy to improve cancer therapeutic efficacy. Herein, we designed novel pH/reduction dual-responsive and folate decorated polymeric micelles (FA Co-PMs) as theranostic nanocarrier to co-encapsulate doxorubicin (DOX) and indocyanine green (ICG) for targeted NIR imaging and chemo-photothermal combination therapy. The Co-PMs triggered DOX release in response to acid pH and reduction environment and exhibited excellent temperature conversion with laser irradiation. The results indicated FA Co-PMs achieved significant targeting to BEL-7404 cells in vitro and efficiently suppressed the BEL-7404 xenografted tumor growth while significantly reduced systemic toxicity in vivo. Therefore, the designed dual-responsive Co-PMs displayed great potential in imaging-guided cancer chemo-photothermal combination therapy as theranostic nanocarriers.

Bubble-generating polymersomes loaded with both indocyanine green and doxorubicin for effective chemotherapy combined with photothermal therapy

The combination of chemotherapy and photothermaltherapy (PTT) via stimuli-responsive nanovesicles has great potential in tumor treatment. In the present study, bubble-generating polymersomes, which can generate bubbles in response to low pH or hyperthermia, were fabricated to simultaneously encapsulate chemotherapeutic drug and photosensitizing agent for the synergistic chemo-photothermal tumor therapy. Photosensitizer indocyanine green (ICG) was encapsulated into the bilayer of polymersomes formed by amphiphilic triblock copolymer PCL₈₀₀₀-PEG₈₀₀₀-PCL₈₀₀₀ through thin film re-hydration method, while chemotherapeutic doxorubicin (DOX) was loaded into the hydrophilic lumen using a transmembrane ammonium bicarbonate gradient loading procedure. Under acidic condition or laser irradiation, the ammonium bicarbonate (NH₄HCO₃) encapsulated in the bubble-generating DOX-ICG-co-delivery polymersomes (BG-DIPS) would decompose to produce CO₂ bubbles, resulting in destruction of vesicle structure and rapid drug release. In vitro drug release study confirmed that acidic environment and NIR laser irradiation could accelerate DOX release from the BG-DIPS. Cellular uptake study indicated that laser-induced hyperthermia highly enhanced endocytosis of BG-DIPS into 4T1-Luc cancer cells. In vitro cytotoxicity study demonstrated that BG-DIPS exhibited much higher cytotoxicity than free drugs under laser irradiation. In vivo biodistribution study indicated that BG-DIPS could accumulate in the tumor region, prolong drug retention, and increase photothermal conversion efficiency. Furthermore, in vivo antitumor study showed that BG-DIPS with laser irradiation efficiently inhibited 4T1-Luc tumor growth with reduced systemic toxicity. Hence, the formulated bubble-generating polymersomes system was a superior multifunctional nanocarrier for stimuli-response controlled drug delivery and combination chemo-photothermal tumor therapy.

STATEMENT OF SIGNIFICANCE

The combination of chemotherapy and photothermaltherapy via stimuli-responsive nanovesicles has great potential in tumor treatment. Herein, bubble-generating polymersomes, which can generate bubbles in response to low pH or hyperthermia, were fabricated to simultaneously encapsulate chemotherapeutic drug (DOX) and photosensitizing agent (ICG) for the synergistic chemo-photothermal tumor therapy. The results in vitro and in vivo demonstrated that bubble-generating DOX-ICG-co-delivery polymersomes (BG-DIPS) would accelerate DOX release from the BG-DIPS and accumulate in the tumor region, prolong drug retention, and increase photothermal conversion efficiency. BG-DIPS with laser irradiation could efficiently inhibited 4T1-Luc tumor growth with reduced systemic toxicity. Hence, the formulated bubble-generating polymersomes system was a superior multifunctional nanocarrier for stimuli-response controlled drug delivery and combination chemo-photothermal tumor therapy.

Association of body weight gain with muscle, fat, and liver expression levels of growth hormone receptor, insulin-like growth factor I, and beta-adrenergic receptor mRNAs in steers

The physiological basis of feed efficiency is unclear. Administration of GH or beta-adrenergic agonists improves feed efficiency in various animals. The objective of this study was to test the hypothesis that more efficient cattle have greater expression of GH receptor (GHR) or beta-adrenergic receptor (ADRB) mRNA in skeletal muscle, fat, and liver, the major target tissues of GH and beta-adrenergic agonists. Fifty Angus steers were fed a finishing diet for 75 d to determine residual feed intake (RFI). Carcass measures, skeletal muscle, subcutaneous fat, and liver samples were collected from the top 10 high-RFI steers and top 10 low-RFI steers at slaughter. Abundances of GHR, insulin-like growth factor I (IGF1), IGF1 receptor (IGF1R), beta-1 adrenergic receptor (ADRB1), ADRB2, and ADRB3 mRNAs were quantified by real-time reverse transcription-PCR. Low-RFI steers consumed 11% less dry matter intake than high-RFI steers (P = 0.004). Low- and high-RFI steers, however, did not differ in ADG or other growth or carcass measures. Low-RFI steers had a tendency to have smaller birth weights than high-RFI steers (P = 0.089). The expression levels of GHR, IGF1, IGF1R, ADRB1, ADRB2, and ADRB3 mRNAs in muscle, fat, and liver were neither different (P > 0.1) between high- and low-RFI steers nor correlated (P > 0.1) with RFI. These results do not support our original hypothesis. However, the expression levels of GHR, IGF1, and IGF1R mRNAs in muscle and fat were positively correlated with ADG (r = 0.52 to 0.65, P = 0.002 to 0.02), whereas the expression levels of GHR mRNA (r = -0.50, P = 0.03) and IGF1 mRNA (r = -0.47, P = 0.04) in the liver were negatively correlated with ADG. These results suggest that the GHR, IGF1, and IGF1R mRNA expression levels in the muscle and fat have a positive effect, whereas the GHR and IGF1 mRNA expression levels in the liver have a negative effect on postweaning body weight gain in cattle.

Translesional pressure gradient and leptomeningeal collateral status in symptomatic middle cerebral artery stenosis

BACKGROUND AND PURPOSE

Leptomeningeal collateral (LMC) status governs the prognosis of large artery occlusive stroke, although factors determining LMC status are not fully elucidated. The aim was to investigate metrics affecting LMC status in such patients by using computational fluid dynamics (CFD) models based on computed tomography angiography (CTA).

METHODS

In this cross-sectional study, patients with recent ischaemic stroke or transient ischaemic attack attributed to atherosclerotic M1 middle cerebral artery (MCA) stenosis (50%-99%) were recruited. Demographic, clinical and imaging data of these patients were collected. Ipsilesional LMC status was graded as good or poor by assessing the laterality of anterior and posterior cerebral arteries in CTA. A CFD model based on CTA was constructed to reflect focal hemodynamics in the distal internal carotid artery, M1 MCA and A1 anterior cerebral artery. Pressure gradients were calculated across culprit MCA stenotic lesions in CFD models. Predictors for good LMC status were sought in univariate and multivariate analyses.

RESULTS

Amongst the 85 patients enrolled (mean age 61.5 ± 10.9 years), 38 (44.7%) had good ipsilesional LMC status. The mean pressure gradient across MCA lesions was 14.8 ± 18.1 mmHg. Advanced age (P = 0.030) and a larger translesional pressure gradient (P = 0.029) independently predicted good LMCs. A lower fasting blood glucose level also showed a trend for good LMCs (P = 0.058).

CONCLUSIONS

Our study suggested a correlation between translesional pressure gradient and maturation of LMCs in intracranial atherosclerotic disease. Further studies with more exquisite and dynamic monitoring of cerebral hemodynamics and LMC evolution are needed to verify the current findings.

Target-specific delivery of siRNA into hepatoma cells' cytoplasm by bifunctional carrier peptide

RNA interference (RNAi) is among the most potential approach for the therapy of hepatocellular carcinoma and the major barrier hindering siRNA therapeutics is the low efficiency of delivery to the desired cells. The current study aimed at developing a novel peptide for more efficient hepatoma targeted siRNA delivery, by combining luteinizing hormone-releasing hormone with hepatoma targeting specificity and MPG^△NLS with cytoplasm-delivery tendency. The developed bifunctional peptide LHRH-MPG^△NLS and siRNA were mixed together and resulted in LHRH-MPG^△NLS/siRNA polyplexes through self-assembly. The polyplexes were characterized by agarose gel retardation and dynamic light scatting analysis. Hepatoma targeting specificity was analyzed with the GE IN Cell Analyzer 2000 High-Content Cellular Analysis System after cell transfection, and the effect of RNA interference was detected by RT-PCR. The results demonstrated that LHRH-MPG^△NLS was able to assemble with siRNA to form stable and nano-sized peptide/siRNA polyplexes, which could inhibit the expression of the target gene and was essentially non-cytotoxic, as compared with the commercial transfection reagent lipofectamine 2000.

Folate-targeted polymersomes loaded with both paclitaxel and doxorubicin for the combination chemotherapy of hepatocellular carcinoma

Combination chemotherapy is a promising method of improving cancer treatment, but the distinct pharmacokinetics of combined drugs and non-specific drug distribution slow down the development in the clinic. In this study, folate (FA) receptor-targeted polymersomes with apparent bilayered lamellar structure were successfully developed to co-encapsulate a hydrophobic-hydrophilic chemotherapeutic drug pair (PTX and DOX) in a single vesicle for enhancing the combination chemotherapeutic effect. Hydrophobic PTX was loaded into the thick hydrophobic lamellar membrane by the self-assembly of triblock copolymer PCL₈₀₀₀-PEG₈₀₀₀-PCL₈₀₀₀, while hydrophilic DOX was encapsulated into the hydrophilic reservoir using a trans-membrane ammonium sulfate gradient method. In vitro release study indicated that the drugs were released from the polymersomes in a controlled and sustained manner. Cellular uptake study indicated that FA-targeted Co-PS had higher internalization efficiency in FA receptor-overexpressing BEL-7404 cells than non-targeted Co-PS. In vitro cytotoxicity assay demonstrated that FA-targeted Co-PS exhibited less cytotoxic effect than free drug cocktail, but suppressed the growth of tumor cells more efficiently than non-targeted Co-PS. Ex vivo imaging biodistribution studies revealed that FA-targeted Co-PS led to highly efficient targeting and accumulation in the BEL-7404 xenograft tumor. Furthermore, the in vivo antitumor study showed that the combination chemotherapy of polymersomes to BEL-7404 tumor via intravenous injection was superior to free drug cocktail treatment, and the FA-targeted Co-PS exhibited significantly higher tumor growth inhibition than non-targeted Co-PS group. Therefore, the newly developed FA-targeted co-delivery polymersomes hold great promise for simultaneous delivery of multiple chemotherapeutics and would have great potential in tumor-targeting and combination chemotherapy.

STATEMENT OF SIGNIFICANCE

Combination chemotherapy is a promising method of improving cancer treatment, but the distinct pharmacokinetics of combined drugs and non-specific drug distribution slow down the development in the clinic. In our study, novel folate-targeted co-delivery polymersomes (Co-PS) were successfully developed to encapsulate a hydrophobic-hydrophilic chemotherapeutic drug pair (paclitaxel and doxorubicin) into the different compartments of the vesicle. In vivo studies revealed that the combination chemotherapy of polymersomes to BEL-7404 xenograft tumor via intravenous injection was superior to free drug cocktail treatment, and the FA-targeted Co-PS exhibited significantly higher tumor growth inhibition than non-targeted Co-PS group. Therefore, the newly developed FA-targeted co-delivery polymersomes hold great promise for simultaneous delivery of multiple chemotherapeutics and would have great potential in tumor-targeting and combination chemotherapy.

Simultaneous monitoring of the drug release and antitumor effect of a novel drug delivery system-MWCNTs/DOX/TC

Monitoring drug release and therapeutic efficacy is crucial for developing drug delivery systems. Our preliminary study demonstrated that, as compared with pristine multiwalled carbon nanotubes (MWCNTs), transactivator of transcription (TAT)-chitosan functionalized MWCNTs (MWCNTs-TC) were a more promising candidate for drug delivery in cancer therapy. In the present study, a MWCNTs/TC-based drug delivery system was developed for an anticancer drug, doxorubicin (DOX). The drug loading and in vitro release profiles, cellular uptake and cytotoxicity were assessed. More importantly, the in vivo drug release and antitumor effect of MWCNTs/DOX/TC were evaluated by noninvasive fluorescence and bioluminescence imaging. It was demonstrated that MWCNTs/DOX/TC can be efficiently taken up by BEL-7402 hepatoma cells. The release of DOX from MWCNTs/DOX/TC was faster under lower pH condition, which was beneficial for intrcellular drug release. The in vivo release process of DOX and antitumor effect in animal model were monitored simultaneously by noninvasive fluorescence and luminescence imaging, which demonstrated the application potential of MWCNTs/DOX/TC for cancer therapy.

Purely electronic mechanism of electrolyte gating of indium tin oxide thin films

Epitaxial indium tin oxide films have been grown on both LaAlO₃ and yttria-stabilized zirconia substrates using RF magnetron sputtering. Electrolyte gating causes a large change in the film resistance that occurs immediately after the gate voltage is applied, and shows no hysteresis during the charging/discharging processes. When two devices are patterned next to one another and the first one gated through an electrolyte, the second one shows no changes in conductance, in contrast to what happens in materials (like tungsten oxide) susceptible to ionic electromigration and intercalation. These findings indicate that electrolyte gating in indium tin oxide triggers a pure electronic process (electron depletion or accumulation, depending on the polarity of the gate voltage), with no electrochemical reactions involved. Electron accumulation occurs in a very thin layer near the film surface, which becomes highly conductive. These results contribute to our understanding of the electrolyte gating mechanism in complex oxides and may be relevant for applications of electric double layer transistor devices.