An overview of technical considerations for Western blotting applications to physiological research

Advanced Glycation End Products (AGEs): Biochemistry, Signaling, Analytical Methods, and Epigenetic Effects

The advanced glycation end products (AGEs) are organic molecules formed in any living organisms with a great variety of structural and functional properties. They are considered organic markers of the glycation process. Due to their great heterogeneity, there is no specific test for their operational measurement. In this review, we have updated the most common chromatographic, colorimetric, spectroscopic, mass spectrometric, and serological methods, typically used for the determination of AGEs in biological samples. We have described their signaling and signal transduction mechanisms and cell epigenetic effects. Although mass spectrometric analysis is not widespread in the detection of AGEs at the clinical level, this technique is highly promising for the early diagnosis and therapeutics of diseases caused by AGEs. Protocols are available for high-resolution mass spectrometry of glycated proteins although they are characterized by complex machine management. Simpler procedures are available although much less precise than mass spectrometry. Among them, immunochemical tests are very common since they are able to detect AGEs in a simple and immediate way. In these years, new methodologies have been developed using an in vivo novel and noninvasive spectroscopic methods. These methods are based on the measurement of autofluorescence of AGEs. Another method consists of detecting AGEs in the human skin to detect chronic exposure, without the inconvenience of invasive methods. The aim of this review is to compare the different approaches of measuring AGEs at a clinical perspective due to their strict association with oxidative stress and inflammation.

Affinity-Bead Assisted Mass Spectrometry (Affi-BAMS): A Multiplexed Microarray Platform for Targeted Proteomics

The ability to quantitatively probe diverse panels of proteins and their post-translational modifications (PTMs) across multiple samples would aid a broad spectrum of biological, biochemical and pharmacological studies. We report a novel, microarray analytical technology that combines immuno-affinity capture with Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI MS), which is capable of supporting highly multiplexed, targeted proteomic assays. Termed "Affinity-Bead Assisted Mass Spectrometry" (Affi-BAMS), this LC-free technology enables development of highly specific and customizable assay panels for simultaneous profiling of multiple proteins and PTMs. While affinity beads have been used previously in combination with MS, the Affi-BAMS workflow uses enrichment on a single bead that contains one type of antibody, generally capturing a single analyte (protein or PTM) while having enough binding capacity to enable quantification within approximately 3 orders of magnitude. The multiplexing capability is achieved by combining Affi-BAMS beads with different protein specificities. To enable screening of bead-captured analytes by MS, we further developed a novel method of performing spatially localized elution of targets from individual beads arrayed on a microscope slide. The resulting arrays of micro spots contain highly concentrated analytes localized within 0.5 mm diameter spots that can be directly measured using MALDI MS. While both intact proteins and protein fragments can be monitored by Affi-BAMS, we initially focused on applying this technology for bottom-up proteomics to enable screening of hundreds of samples per day by combining the robust magnetic bead-based workflow with the high throughput nature of MALDI MS acquisition. To demonstrate the variety of applications and robustness of Affi-BAMS, several studies are presented that focus on the response of 4EBP1, RPS6, ERK1/ERK2, mTOR, Histone H3 and C-MET to stimuli including rapamycin, H2O2, EPO, SU11274, Staurosporine and Vorinostat.

miR-424 Promotes Bovine Adipogenesis Through an Unconventional Post-Transcriptional Regulation of STK11

Adipose tissue is the largest energy reservoir and secretory organ in the animal body, and is essential for maintaining normal physiological functions and metabolic balance. MicroRNAs regulate the process of adipogenic differentiation through post-transcriptional regulatory mechanisms. In the present study, miR-424 was upregulated during bovine adipocyte differentiation both in vivo and in vitro. The overexpression and interference of miR-424 exhibited the positive regulatory role in the differentiation of bovine adipocytes. Furthermore, miR-424 directly binds to the three prime untranslated region (3' UTR) of serine/threonine kinase 11 (STK11, also called LKB1), a master upstream gene in the AMP-activated protein kinase (AMPK) cascade, and up-regulates its expression. Functional studies showed that the knockdown of STK11 attenuated the pro-adipogenic effect of miR-424. Post-transcriptional regulation of STK11 by miR-424 was mediated potentially in an RNA binding protein (RBP) binding site-dependent manner. In conclusion, our study shows that miR-424 promotes bovine adipogenesis through an unconventional post-transcriptional regulation of STK11, which may serve as a potential target for the regulation of bovine adipogenesis and the improvement of livestock breeding efficiency.

Glutamine-stimulated in vitro hypertrophy is preserved in muscle cells from older women

Age-related loss of muscle mass may result from reduced protein synthesis stimulation in response to anabolic stimuli, such as amino acid (AA) supplementation. The exact etiology of anabolic resistance to AA remains unclear. Therefore, the aim of this study was to investigate the anabolic response [cell size, protein synthesis and mechanistic target of rapamycin (mTOR) pathway] to the AA glutamine (a strong anabolic AA highly present in skeletal muscle) in myotubes obtained from 8 young (YW; 21-35 yrs) and 8 older (OW; 65-70 yrs) healthy women. This in vitro model of human primary myogenic cells explores the intrinsic behavior of muscle cells, while excluding potential influences of external factors. We showed that despite lower muscle mass, strength and cardiorespiratory fitness in OW compared to YW, myotube size (myotube diameter and area) and protein synthesis were not altered in OW, and glutamine-induced myotube hypertrophy and protein synthesis were preserved in OW. Apart from a lower glutamine-induced increase in P70S6 kinase phosphorylation in OW, no significant differences in other components of the mTOR pathway were observed between groups. Altogether, our data support the idea that the intrinsic capacity of muscle cells to respond to glutamine stimulation is preserved in healthy older women.

Detection of circulating anti-retinal antibodies in dogs with sudden acquired retinal degeneration syndrome using indirect immunofluorescence: A case-control study

Sudden acquired retinal degeneration syndrome (SARDS) in dogs is proposed to have an immune-mediated etiology. However, there is conflicting evidence regarding the presence of antiretinal antibodies, as assessed by western blotting, in the serum of SARDS patients. Because of the possibility that antibodies recognize only conformational epitopes, we hypothesized that a more sensitive method to investigate circulating retinal autoantibodies in SARDS is immunofluorescence. Sera from 14 dogs with early SARDS, and 14 age- and breed-matched healthy control dogs were screened for circulating antiretinal IgG, IgM, IgE and IgA using indirect immunofluorescence on lightly fixed frozen sections of normal canine retina. Controls without canine serum were also performed. A nuclear counterstain was used to identify cellular retinal layers. Images were obtained using a fluorescence microscope, and 2-3 separate masked observers graded retinal layers for fluorescence staining intensity using a 0-3 scale. Total circulating IgG and IgM was assessed by radial immunodiffusion. Statistical analysis was performed using 2-way ANOVA, paired 2-tailed student's t-test and correlation analysis. Intensity of IgG staining of photoreceptor outer segments was significantly higher using serum from dogs with SARDS compared with healthy controls in 2/3 observers (P < 0.05). Intensity of IgM staining throughout the retina was higher in SARDS dogs compared to matched healthy controls (P < 0.0001), although no specific retinal layer was statistically significant. There were no differences in staining intensity for IgE or IgA. Dogs with SARDS had a comparably lower circulating IgG and higher IgM than healthy controls (P = 0.01 and 0.001 respectively) and IgG and IgM were negatively correlated (r = -0.69, P = 0.007). Despite having decreased serum IgG compared with healthy controls, circulating IgG in dogs with SARDS binds photoreceptor outer segments to a greater extent. Dogs with SARDS have a relatively higher circulating IgM than matched healthy controls. The pathogenic nature of these antibodies is unknown.

A systematic approach to quantitative Western blot analysis

Attaining true quantitative data from WB requires that all the players involved in the procedure are quality controlled including the user. Appropriate protein extraction method, electrophoresis, and transfer of proteins, immunodetection of blotted protein by antibodies, and the ultimate step of imaging and analyzing the data is nothing short of a symphony. Like with any other technology in life-sciences research, Western blotting can produce erroneous and irreproducible data. We provide a systematic approach to generate quantitative data from Western blot experiments that incorporates critical validation steps to identify and minimize sources of error and variability throughout the Western blot process.

Impact of in ovo administered pioneer colonizers on intestinal proteome on day of hatch

Pioneer colonization of the gastrointestinal tract (GIT) by bacteria is thought to have major influence on neonatal tissue development. Previous studies have shown in ovo inoculation of embryos with saline (S), species of Citrobacter (C, C2), or lactic acid bacteria (L) resulted in an altered microbiome on day of the hatch (DOH). The present study investigated GIT proteomic changes at DOH in relation to different inoculations. Embryos were inoculated in ovo with S or ∼10² cfu of C, C2, or L at 18 embryonic days. On DOH, the GIT was collected, and tissue proteins were extracted for analysis via tandem mass spectrometry. A total of 493 proteins were identified for differential comparison with S at P ≤ 0.10. Different levels were noted in 107, 39, and 78 proteins in C, C2, and L groups, respectively, which were uploaded to Ingenuity Pathway Analysis to determine canonical pathways and biological functions related to these changes. Three members of the cytokine family (interleukin [IL]-1β, IL6, and Oncostatin M) were predicted to be activated in C2, indicated with Z-score ≥ 1.50, which suggested an overall proinflammatory GIT condition. This was consistent with the activation of the acute-phase response signaling pathway seen exclusively in C2 (Z-score = 2.00, P < 0.01). However, activation (Z-score = 2.00) of IL-13, upregulation of peroxiredoxin-1 and superoxide dismutase 1, in addition to activation of nitric oxide signaling in the cardiovascular system of the L treatment may predict a state of increased antioxidant capacity and decreased inflammatory status. The nuclear factor erythroid 2-related factor 2 (NRF2)-mediated oxidative stress response (Z-score = 2.00, P < 0.01) was predicted to be upregulated in C which suggested that chicks were in an inflammatory state and associated oxidative stress, but the impact of these pathways differed from that of C2. These changes in the proteome suggest that pioneer colonizing microbiota may have a strong impact on pathways associated with GIT immune and cellular development.

A multi-epitope plant-made chimeric protein (LTBentero) targeting common enteric pathogens is immunogenic in mice

KEY MESSAGE

A plant-based multiepitopic protein (LTBentero) containing epitopes from ETEC, S. typhimurium, and V. parahaemolyticus was produced in plants cells and triggered systemic and intestinal humoral responses in immunized mice. Around 200 million people suffer gastroenteritis daily and more than 2 million people die annually in developing countries due to such pathologies. Vaccination is an alternative to control this global health issue, however new low-cost vaccines are needed to ensure proper vaccine coverage. In this context, plants are attractive hosts for the synthesis and delivery of subunit vaccines. Therefore, in this study a plant-made multiepitopic protein named LTBentero containing epitopes from antigens of enterotoxigenic E. coli, S. typhimurium, and V. parahaemolyticus was produced and found immunogenic in mice. The LTBentero protein was expressed in tobacco plants at up to 5.29 µg g-1 fresh leaf tissue and was deemed immunogenic when administered to BALB/c mice either orally or subcutaneously. The plant-made LTBentero antigen induced specific IgG (systemic) and IgA (mucosal) responses against LTB, ST, and LptD epitopes. In conclusion, multiepitopic LTBentero was functionally produced in plant cells, being capable to trigger systemic and intestinal humoral responses and thus it constitutes a promising oral immunogen candidate in the fight against enteric diseases.

Tyrosol prevents AlCl3 induced male reproductive damage by suppressing apoptosis and activating the Nrf-2/HO-1 pathway

Aluminium is a ubiquitous element that occurs naturally in the soil making human exposure to it is unavoidable. Tyrosol is present in olive oil and is known to have antioxidant effects. Therefore, the present study explores the toxic effects of aluminium chloride (AlCl₃ ) and evaluates the possible protection by tyrosol in male rats. Testicular injury was induced by the administration of AlCl₃ (34 mg kg^-1  day^-1 ). Rats were treated with either tyrosol (20 mg kg^-1 day^-1 ) or AlCl3 (34 mg kg^-1 day^-1 ). The experiment lasted for 10 weeks. Biochemical, histopathological and protein expression profiles were determined to decipher the role of tyrosol in protecting the cellular damage. Further, histomorphometric analyses of testes showed deranged architecture along with other noted abnormalities. AlCl₃ group rats' testes showed decreased GSH levels, CAT activities, Nrf-2, HO-1, bcl-2 expressions and sperm motility whereas increased caspase-3 expressions, MDA levels, abnormal and dead/live sperm ratio. However, tyrosol treatment attenuated these changes. The present results demonstrate the beneficial role of tyrosol treatment in AlCl₃ induced testicular toxicity alterations of rat.

Antibody validation for Western blot: By the user, for the user

Well-characterized antibody reagents play a key role in the reproducibility of research findings, and inconsistent antibody performance leads to variability in Western blotting and other immunoassays. The current lack of clear, accepted standards for antibody validation and reporting of experimental details contributes to this problem. Because the performance of primary antibodies is strongly influenced by assay context, recommendations for validation and usage are unique to each type of immunoassay. Practical strategies are proposed for the validation of primary antibody specificity, selectivity, and reproducibility using Western blot analysis. The antibody should produce reproducible results within and between Western blotting experiments and the observed effect confirmed with a complementary or orthogonal method. Routine implementation of standardized antibody validation and reporting in immunoassays such as Western blotting may promote improved reproducibility across the global life sciences community.

Testosterone therapy induces molecular programming augmenting physiological adaptations to resistance exercise in older men

BACKGROUND

The andropause is associated with declines in serum testosterone (T), loss of muscle mass (sarcopenia), and frailty. Two major interventions purported to offset sarcopenia are anabolic steroid therapies and resistance exercise training (RET). Nonetheless, the efficacy and physiological and molecular impacts of T therapy adjuvant to short-term RET remain poorly defined.

METHODS

Eighteen non-hypogonadal healthy older men, 65-75 years, were assigned in a random double-blinded fashion to receive, biweekly, either placebo (P, saline, n = 9) or T (Sustanon 250 mg, n = 9) injections over 6 week whole-body RET (three sets of 8-10 repetitions at 80% one-repetition maximum). Subjects underwent dual-energy X-ray absorptiometry, ultrasound of vastus lateralis (VL) muscle architecture, and knee extensor isometric muscle force tests; VL muscle biopsies were taken to quantify myogenic/anabolic gene expression, anabolic signalling, muscle protein synthesis (D₂ O), and breakdown (extrapolated).

RESULTS

Testosterone adjuvant to RET augmented total fat-free mass (P=0.007), legs fat-free mass (P=0.02), and appendicular fat-free mass (P=0.001) gains while decreasing total fat mass (P=0.02). Augmentations in VL muscle thickness, fascicle length, and quadriceps cross-section area with RET occured to a greater extent in T (P < 0.05). Sum strength (P=0.0009) and maximal voluntary contract (e.g. knee extension at 70°) (P=0.002) increased significantly more in the T group. Mechanistically, both muscle protein synthesis rates (T: 2.13 ± 0.21%·day^-1 vs. P: 1.34 ± 0.13%·day^-1 , P=0.0009) and absolute breakdown rates (T: 140.2 ± 15.8 g·day^-1 vs. P: 90.2 ± 11.7 g·day^-1 , P=0.02) were elevated with T therapy, which led to higher net turnover and protein accretion in the T group (T: 8.3 ± 1.4 g·day^-1 vs. P: 1.9 ± 1.2 g·day^-1 , P=0.004). Increases in ribosomal biogenesis (RNA:DNA ratio); mRNA expression relating to T metabolism (androgen receptor: 1.4-fold; Srd5a1: 1.6-fold; AKR1C3: 2.1-fold; and HSD17β3: two-fold); insulin-like growth factor (IGF)-1 signalling [IGF-1Ea (3.5-fold) and IGF-1Ec (three-fold)] and myogenic regulatory factors; and the activity of anabolic signalling (e.g. mTOR, AKT, and RPS6; P < 0.05) were all up-regulated with T therapy. Only T up-regulated mitochondrial citrate synthase activity (P=0.03) and transcription factor A (1.41 ± 0.2-fold, P=0.0002), in addition to peroxisome proliferator-activated receptor-γ co-activator 1-α mRNA (1.19 ± 0.21-fold, P=0.037).

CONCLUSIONS

Administration of T adjuvant to RET enhanced skeletal muscle mass and performance, while up-regulating myogenic gene programming, myocellular translational efficiency and capacity, collectively resulting in higher protein turnover, and net protein accretion. T coupled with RET is an effective short-term intervention to improve muscle mass/function in older non-hypogonadal men.

Simultaneous detection and quantification of DNA and protein biomarkers in spectrum of cardiovascular diseases in a microfluidic microbead chip

The rapid and simultaneous detection of DNA and protein biomarkers is necessary to detect the outbreak of a disease or to monitor a disease. For example, cardiovascular diseases are a major cause of adult mortality worldwide. We have developed a rapidly adaptable platform to assess biomarkers using a microfluidic technology. Our model mimics autoantibodies against three proteins, C-reactive protein (CRP), brain natriuretic peptide (BNP), and low-density lipoprotein (LDL). Cell-free mitochondrial DNA (cfmDNA) and DNA controls are detected via fluorescence probes. The biomarkers are covalently bound on the surface of size- (11–15 μm) and dual-color encoded microbeads and immobilized as planar layer in a microfluidic chip flow cell. Binding events of target molecules were analyzed by fluorescence measurements with a fully automatized fluorescence microscope (end-point and real-time) developed in house. The model system was optimized for buffers and immobilization strategies of the microbeads to enable the simultaneous detection of protein and DNA biomarkers. All prime target molecules (anti-CRP, anti-BNP, anti-LDL, cfmDNA) and the controls were successfully detected both in independent reactions and simultaneously. In addition, the biomarkers could also be detected in spiked human serum in a similar way as in the optimized buffer system. The detection limit specified by the manufacturer is reduced by at least a factor of five for each biomarker as a result of the antibody detection and kinetic experiments indicate that nearly 50 % of the fluorescence intensity is achieved within 7 min. For rapid data inspection, we have developed the open source software digilogger, which can be applied for data evaluation and visualization.

A flexible, robust microbead-based assay for quantification and normalization of target protein concentrations

Although there are many methods for quantifying the concentration of specific proteins in samples, current techniques are technically challenging or do not easily lend themselves to normalization. Here, we describe a microbead-based assay for quantifying specific protein concentration(s) that is high-throughput, inexpensive, simple-to-use, and intrinsically incorporates normalization against the sample total protein content. This assay, termed the FRANC assay, exploits high affinity biotin-streptavidin binding to couple sample proteins to streptavidin-labelled magnetic microbeads. Proteins are then antibody-probed, followed by labeling of proteins on the microbead with fluorescent dye, and flow cytometry-based analysis. The FRANC assay demonstrates detection limits for target proteins in the femtogram range, with a linear range up to as much as 10 ng. Normalization of target protein concentrations resulted in an 80% reduction in variability as compared to non-normalized measurements. We conclude that the FRANC assay offers attractive advantages over current methods for quantifying specific protein(s) in samples.

Detection of autoantibodies in central nervous system inflammatory disorders: Clinical application of cell-based assays

The identification of autoantibodies in central nervous system (CNS) inflammatory disorders improves diagnostic accuracy and the identification of patients with a relapsing disease. Usual methods to detect autoantibodies are usually divided into 3 categories: tissue-based assays, protein-based assays and cell-based assays (CBA). Tissue-based assays are commonly used for initial identification of autoantibodies based on staining patterns and co-localization. Once the antigen is known, autoantibodies can be detected using other antigen-specific methods based on recombinant proteins and CBA using transfected cells expressing the protein in their cell membranes. Compared to traditional methods using recombinant proteins such as ELISA and western blot, the CBA have advantage of detecting conformational sensitive antibodies using natively folded proteins in the cell membrane. This article reviews the utility of CBA into the clinical practice.

Inactivation of Horseradish Peroxidase by Acid for Sequential Chemiluminescent Western Blot

Chemiluminescent western blot (WB) is often performed sequentially for detection of overlapping proteins; in between, prior antibodies must be stripped or the conjugated horseradish peroxidase (HRP) inactivated. However, often, stripping either is insufficient to remove all the bound antibodies or causes protein loss, whereas treatment with hydrogen peroxide, a popular way to inactivate HRP, may affect epitope recognition as the authors previously reported. To date, an ideal method for sequential chemiluminescent WB is still missing. Here it is demonstrated that acid equivalent to 10% acetic acid can efficiently inactivate HRP, allowing sequential probing without protein loss or epitope damage.

Purification of Recombinant ADAMTSL2

Recombinantly produced proteins are used in many biological disciplines. However, their purity and quality are vital for downstream applications used to determine their structure and functions. Several purification and detection strategies can be used in combination to obtain protein samples with homogeneity and structural conformity. Here we detail the protocols involved in the purification of ADAMTSL2 from mammalian cells. We also describe the protocols used to validate the purity of the protein samples.

Molecular regulation of human skeletal muscle protein synthesis in response to exercise and nutrients: a compass for overcoming age-related anabolic resistance

Skeletal muscle mass, a strong predictor of longevity and health in humans, is determined by the balance of two cellular processes, muscle protein synthesis (MPS) and muscle protein breakdown. MPS seems to be particularly sensitive to changes in mechanical load and/or nutritional status; therefore, much research has focused on understanding the molecular mechanisms that underpin this cellular process. Furthermore, older individuals display an attenuated MPS response to anabolic stimuli, termed anabolic resistance, which has a negative impact on muscle mass and function, as well as quality of life. Therefore, an understanding of which, if any, molecular mechanisms contribute to anabolic resistance of MPS is of vital importance in formulation of therapeutic interventions for such populations. This review summarizes the current knowledge of the mechanisms that underpin MPS, which are broadly divided into mechanistic target of rapamycin complex 1 (mTORC1)-dependent, mTORC1-independent, and ribosomal biogenesis-related, and describes the evidence that shows how they are regulated by anabolic stimuli (exercise and/or nutrition) in healthy human skeletal muscle. This review also summarizes evidence regarding which of these mechanisms may be implicated in age-related skeletal muscle anabolic resistance and provides recommendations for future avenues of research that can expand our knowledge of this area.

Immunofluorescence can assess the efficacy of mTOR pathway therapeutic agent Everolimus in breast cancer models

When breast cancer patients start to exhibit resistance to hormonal therapy or chemotherapy, the mTOR inhibitor everolimus can be considered as an alternative therapeutic agent. Everolimus can deregulate the PI3K/AKT/mTOR pathway and affect a range of cellular functions. In some patients, the agent does not exhibit the desired efficacy and, even worse, not without the associated side effects. This study assessed the use of immunofluorescence (IF) as a modality to fill this unmet need of predicting the efficacy of everolimus prior to administration. Cell viability and MTT assays based on IF intensities of pho-4EBP1 Thr37/46 and pho-S6K1 Ser424 on breast cancer cells (Hs578T, MCF7, BT474, MDA-MB-231) and patient-derived cell culture from metastatic sites (ABC-82T and ABC-16TX1) were interrogated. Results show that independent pho-4EBP1 Thr37/46 and pho-S6K1 Ser424 IF expressions can classify data into different groups: everolimus sensitive and resistant. The combined IF baseline intensity of these proteins is predictive of the efficacy of everolimus, and their intensities change dynamically when cells are resistant to everolimus. Furthermore, mTOR resistance is not only consequence of the AKT/mTOR pathway but also through the LKB1 or MAPK/ERK pathway. The LKB1 and pho-GSK3β may also be potential predictive markers for everolimus.

Skeletal muscle signaling responses to resistance exercise of the elbow extensors are not compromised by a preceding bout of aerobic exercise

The current study examined the effects of a preceding bout of aerobic exercise (AE) on subsequent molecular signaling to resistance exercise (RE) of the elbow extensors. Eleven men performed unilateral elbow-extensor AE (~45 min at 70% peak workload) followed by unilateral RE (4 × 7 maximal repetitions) for both arms. Thus, one arm performed AE+RE interspersed with 15 min recovery, whereas the other arm conducted RE alone. Muscle biopsies were taken from the triceps brachii of each arm immediately before (PRE) and 15 min (POST1) and 3 h (POST2) after RE. Molecular markers involved in translation initiation, protein breakdown, mechanosignaling, and ribosome biogenesis were analyzed. Peak power during RE was reduced by 24% (±19%) when preceded by AE ( P < 0.05). Increases in PGC1a and MuRF1 expression were greater from PRE to POST2 in AE+RE compared with RE (18- vs. 3.5- and 4- vs. 2-fold, respectively, interaction, P < 0.05). Myostatin mRNA decreased in both arms ( P < 0.05). Phosphorylation of AMPK (Thr172) increased (2.5-fold), and 4E-BP1 (Thr37/46) decreased (2.0-fold), after AE (interactions, P < 0.05). p70 S6K, yes-associated protein, and c-Jun NH2-terminal kinase phosphorylation were unaltered, whereas focal adhesion kinase decreased ~1.5-fold, and β1-integrin increased ~1.3- to 1.5-fold, (time effect, P < 0.05). Abundance of 45S pre-ribosomal (r)RNA (internally transcribed spacer, ITS) decreased (~30%) after AE (interaction, P < 0.05), whereas CMYC mRNA was greater in AE+RE compared with RE (12-fold, P < 0.05). POLR1B abundance increased after both AE+RE and RE. All together, our results suggest that a single bout of AE leads to an immediate decrease in signaling for translation initiation and ribosome biogenesis. Yet, this did not translate into altered RE-induced signaling during the 3-h postexercise recovery period.

Hyaluronic Acid Nanocapsules as a Platform for Needle-Free Vaccination

Vaccination faces many challenges nowadays, and among them the use of adjuvant molecules and needle-free administration are some of the most demanding. The combination of transcutaneous vaccination and nanomedicine through a rationally designed new-formulation could be the solution to this problem. This study focuses on this rational design. For this purpose, new hyaluronic acid nanocapsules (HA-NCs) have been developed. This new formulation has an oily nucleus with immunoadjuvant properties (due to α tocopherol) and a shell made of hyaluronic acid (HA) and decorated with ovalbumin (OVA) as the model antigen. The resulting nanocapsules are smaller than 100 nm, have a negative superficial charge and have a population that is homogeneously distributed. The systems show high colloidal stability in storage and physiological conditions and high OVA association without losing their integrity. The elevated interaction of the novel formulation with the immune system was demonstrated through complement activation and macrophage viability studies. Ex vivo studies using a pig skin model show the ability of these novel nanocapsules to penetrate and retain OVA in higher quantities in skin when compared to this antigen in the control solution. Due to these findings, HA-NCs are an interesting platform for needle-free vaccination.

Improving the sensitivity of traditional Western blotting via Streptavidin containing Poly-horseradish peroxidase (PolyHRP)

Immunoassays such as ELISAs and Western blotting have been the common choice for protein validation studies for the past several decades. Technical advancements and modifications are continuously being developed to enhance the detection sensitivity of these procedures. Among them, Streptavidin-containing poly-horseradish peroxidase (PolyHRP) based detection strategies have been shown to improve signals in ELISA. The use of commercially available Streptavidin and antibodies conjugated with many HRPs (PolyHRPs) to potentially enhance the detection sensitivity in Western blotting has not been previously investigated in a comprehensive manner. The use of PolyHRP-secondary antibody instead of HRP-secondary antibody increased the Western blotting sensitivity up to 85% depending on the primary antibody used. The use of a biotinylated secondary antibody and commercially available Streptavidin-conjugated with HRP or PolyHRP all resulted in increased sensitivity with respect to antigen detection. Utilizing a biotinylated secondary antibody and Streptavidin-conjugated PolyHRP resulted in as much as a 110-fold increase in Western blotting sensitivity over traditional Western blotting methods. Quantification of troponin I in rat heart lysates showed that the traditional Western blotting method only detected troponin I in ≥2 μg of lysate while Streptavidin-conjugated PolyHRP20 detected troponin I in ≥50 ng of lysate. A modified blocking procedure is also described that eliminated the interference caused by the endogenous biotinylated proteins. These results suggest that Streptavidin-conjugated PolyHRP and PolyHRP secondary antibodies are likely to be commonly utilized for Western blots in the future.

A fixation method for the optimisation of western blotting

Western blotting is the most extensively used technique for the identification and characterisation of proteins and their expression levels. One of the major issues with this technique is the loss of proteins from the blotted membrane during the incubation and washing steps, which affects its sensitivity and reproducibility. Here, we have optimised the fixation conditions for immunoblotting and lectin blotting on electroblotted polyvinylidene difluoride and nitrocellulose membranes, using a combination of organic solvents and heating. Loss of proteins from polyvinylidene difluoride membranes was greatly reduced using this approach, the intensity of lectin blotting and immunoblotting was shown to increase 2.8- to 15-fold and 1.8- to 16-fold, respectively, compared with that samples without treated. Using the optimised method, cystic fibrosis transmembrane regulator and hypoxia-inducible factor 1, two difficult-to-analyse proteins with important physiological and pathological roles, were effectively detected. Additionally, it may help the identification of novel diagnostic markers for prostate cancer.

MiR-34b-5p Mediates the Proliferation and Differentiation of Myoblasts by Targeting IGFBP2

As key post-transcriptional regulators, microRNAs (miRNAs) play an indispensable role in skeletal muscle development. Our previous study suggested that miR-34b-5p and IGFBP2 could have a potential role in skeletal muscle growth. Our goal in this study is to explore the function and regulatory mechanism of miR-34b-5p and IGFBP2 in myogenesis. In this study, the dual-luciferase reporter assay and Western blot analysis showed that IGFBP2 is a direct target of miR-34b-5p. Flow cytometric analysis and EdU assay showed that miR-34b-5p could repress the cell cycle progression of myoblasts, and miR-34b-5p could promote the formation of myotubes by promoting the expression of MyHC. On the contrary, the overexpression of IGFBP2 significantly facilitated the proliferation of myoblasts and hampered the formation of myotubes. Together, our results indicate that miR-34b-5p could mediate the proliferation and differentiation of myoblasts by targeting IGFBP2.

Identification of non-conserved residues essential for improving the hydrocarbon-producing activity of cyanobacterial aldehyde-deformylating oxygenase

BACKGROUND

Cyanobacteria produce hydrocarbons corresponding to diesel fuels by means of aldehyde-deformylating oxygenase (ADO). ADO catalyzes a difficult and unusual reaction in the conversion of aldehydes to hydrocarbons and has been widely used for biofuel production in metabolic engineering; however, its activity is low. A comparison of the amino acid sequences of highly active and less active ADOs will elucidate non-conserved residues that are essential for improving the hydrocarbon-producing activity of ADOs.

RESULTS

Here, we measured the activities of ADOs from 10 representative cyanobacterial strains by expressing each of them in Escherichia coli and quantifying the hydrocarbon yield and amount of soluble ADO. We demonstrated that the activity was highest for the ADO from Synechococcus elongatus PCC 7942 (7942ADO). In contrast, the ADO from Gloeobacter violaceus PCC 7421 (7421ADO) had low activity but yielded high amounts of soluble protein, resulting in a high production level of hydrocarbons. By introducing 37 single amino acid substitutions at the non-conserved residues of the less active ADO (7421ADO) to make its sequence more similar to that of the highly active ADO (7942ADO), we found 20 mutations that improved the activity of 7421ADO. In addition, 13 other mutations increased the amount of soluble ADO while maintaining more than 80% of wild-type activity. Correlation analysis showed a solubility-activity trade-off in ADO, in which activity was negatively correlated with solubility.

CONCLUSIONS

We succeeded in identifying non-conserved residues that are essential for improving ADO activity. Our results may be useful for generating combinatorial mutants of ADO that have both higher activity and higher amounts of the soluble protein in vivo, thereby producing higher yields of biohydrocarbons.

Eimeria challenge adversely affected long bone attributes linked to increased resorption in 14-day-old broiler chickens

There is limited information on the effects of enteric pathogen on bone quality in rapidly growing broiler chicks. We examined tibia and femur attributes (length, diameter, relative weight of ash content [AC] to the BW, ash concentration [AP]) and serum bone-turnover markers including receptor activator of nuclear factor kappa-B ligand (RANKL) for resorption, alkaline phosphatase (ALP) for mineralization, and selected serum metabolites in 14-day-old broilers challenged with Eimeria. A total of 160 (80 males and 80 females) 1-day-old Ross × Ross 708 chicks were used. Based on BW, birds were placed within sex in cages (5 birds per cage) and fed chick starter diets to day 9 of age. On day 9, half of the cages were orally gavaged with 1 mL of Eimeria culture (100,000 oocysts of E. acervulina and 25,000 oocysts of E. maxima) and the other half (unchallenged control) received 1 mL 0.9% saline in distilled water. On day 14, 2 birds were randomly selected and necropsied for intestinal lesion score, blood, tibia, and femur samples. Data were analyzed in a 2 (challenged vs. unchallenged) × 2 (males vs. females) factorial arrangement. There was no interaction (P > 0.05) between Eimeria and sex on any measurement. Whereas there were no intestinal lesions in unchallenged birds, Eimeria resulted in lesion score (0 to 4) of 3.35, 2.59 and 0.11 in duodenum, jejunum and ileum, respectively. Eimeria challenge decreased (P < 0.05) tibia AC and AP by 10 and 8.2%, respectively but had no (P > 0.10) effect on femur attributes. Generally, males showed (P < 0.05) longer and wider bones with more AC compared with the female. Circulating serum RANKL concentration increased (P = 0.017) in response to Eimeria challenge and was negatively correlated with tibia AC (-0.731; P = 0.021). Our findings showed that Eimeria damage to the intestinal physiology had adverse effects on long bone attributes linked to increased resorption.

Rapid and sensitive detection of the activity of ADAM17 using a graphene oxide-based fluorescence sensor

A disintegrin and metalloproteinase 17 (ADAM17) has become a novel biomarker and potential therapeutic target for the early detection and treatment of human cancers. In this work, by covalently attaching fluorescently labeled ADAM17 substrate peptide (Pep-FAM) molecules to carboxylated graphene oxide (cGO) and monitoring the cleavage of the peptide substrate by ADAM17, we developed a cGO-Pep-FAM fluorescence sensor for the rapid, sensitive and accurate detection of ADAM17. The sensor was highly sensitive with a detection limit of 17.5 picomolar. Furthermore, the sensor was selective: structure similar proteases such as ADAM9 and MMP-9 would not interfere with ADAM17 detection. In addition, simulated serum samples were successfully analyzed. Our developed cGO-Pep-FAM sensing strategy should find useful applications in disease diagnosis and drug screening.

Quantitative Single-Cell Analysis of Isolated Cancer Cells with a Microwell Array

The heterogeneous nature of tumor-cell populations suggests that quantitative analysis at the single-cell level may provide better insights into cancer biology. Specifically, detection of multiple biomarkers from a single cell offers important initial information about cellular behavior. However, conventional approaches limit biomarker detection at the single-cell level. Here, we fabricated a polymer microwell array to capture single cells from prostate-cancer cell lines and quantitatively analyzed the expression of three different cancer-related biomarkers, CD44, EpCAM, and PSMA, without a membrane protein-extraction step. The resulting information on cell-surface biomarker distributions was compared with that from other standard analytical techniques. Interestingly, a large variation in CD44-expression levels was observed when the cell-proliferation cycle was modulated. On the other hand, the expression levels of EpCAM in three different cell lines are consistent among the different analytical methods with the exception of the microarray, where it has a different substrate material to adhere to. This observation clearly emphasizes that biomarker choice and environmental control are critical for properly understanding the single-cell state.

Liraglutide protects against inflammatory stress in non-alcoholic fatty liver by modulating Kupffer cells M2 polarization via cAMP-PKA-STAT3 signaling pathway

Nonalcoholic fatty liver disease (NAFLD) is the second major chronic liver disease world-wide and growing. Current medical treatment of NAFLD is not effective, and there is an urgent need to find new effective drugs. Liraglutide is now the first-line treatment for type 2 diabetes mellitus (T2DM) with promise, according to recent reports, to mitigate the fatty degeneration of the liver. The investigators of the current study discern if liraglutide reduces non-alcoholic fatty liver disease (NAFLD) induced by a high-fat diet using mice via modulating Kupffer cells M2 polarization in the liver. The mice underwent four weeks of intraperitoneal injections of liraglutide (0.6 mg/kg body weight). In the NAFLD model used in this study, the liver index, the body weight, and the serum levels of ALT, AST, total cholesterol, and triglycerides were meaningfully improved. In sections using H&E and Oil Red O staining, hepatic steatosis was significantly improved. Liraglutide decreased liver inflammation and the inflammatory properties of Kupffer cells in the NAFLD mouse model and there was a higher ratio of M2/M1 Kupffer cells. In vitro studies found that Liraglutide treatment modulates Kupffer cells to M2-like activation via the cAMP-PKA-STAT3 signaling pathway. The perilous effects of a high-fat diet were alleviated by liraglutide, including hepatic steatosis, by modulating Kupffer cells M2 polarization via the cAMP-PKA-STAT3 signaling pathway. Liraglutide can indeed reverse the negative effects of NAFLD.

Microparticle Delivery of Protein Markers for Single-Cell Western Blotting from Microwells

Immunoblotting confers protein identification specificity beyond that of immunoassays by prepending protein electrophoresis (sizing) to immunoprobing. To accurately size protein targets, sample analysis includes concurrent analysis of protein markers with known molecular masses. To incorporate protein markers in single-cell western blotting, microwells are used to isolate individual cells and protein marker-coated microparticles. A magnetic field directs protein-coated microparticles to >75% of microwells, so as to 1) deliver a quantum of protein marker to each cell-laden microwell and 2) synchronize protein marker solubilization with cell lysis. Nickel-coated microparticles are designed, fabricated, and characterized, each conjugated with a mixture of histidine-tagged proteins (42.3-100 kDa). Imidazole in the cell lysis buffer solubilizes protein markers during a 30 s cell lysis step, with an observed protein marker release half-life of 4.46 s. Across hundreds of individual microwells and different microdevices, robust log-linear regression fits (R2 > 0.97) of protein molecular mass and electrophoretic mobility are observed. The protein marker and microparticle system is applied to determine the molecular masses of five endogenous proteins in breast cancer cells (GAPDH, β-TUB, CK8, STAT3, ER-α), with <20% mass error. Microparticle-delivered protein standards underpin robust, reproducible electrophoretic cytometry that complements single-cell genomics and transcriptomics.

Osmolality Selectively Offsets the Impact of Hyperthermia on Mouse Skeletal Muscle in vitro

Hyperthermia and dehydration can occur during exercise in hot environments. Nevertheless, whether elevations in extracellular osmolality contributes to the increased skeletal muscle tension, sarcolemmal injury, and oxidative stress reported in warm climates remains unknown. We simulated osmotic and heat stress, in vitro, in mouse limb muscles with different fiber compositions. Extensor digitorum longus (EDL) and soleus (SOL) were dissected from 36 male C57BL6J and mounted at optimal length in tissue baths containing oxygenated buffer. Muscles were stimulated with non-fatiguing twitches for 30 min. Four experimental conditions were tested: isotonic-normothermia (285 mOsm•kg-1 and 35°C), hypertonic-normothermia (300 mOsm•kg-1 and 35°C), isotonic-hyperthermia (285 mOsm•kg-1 and 41°C), and hypertonic-hyperthermia (300 mOsm•kg-1 and 41°C). Passive tension was recorded continuously. The integrity of the sarcolemma was determined using a cell-impermeable fluorescent dye and immunoblots were used for detection of protein carbonyls. In EDL muscles, isotonic and hypertonic-hyperthermia increased resting tension (P < 0.001). Whereas isotonic-hyperthermia increased sarcolemmal injury in EDL (P < 0.001), this effect was absent in hypertonic-hyperthermia. Similarly, isotonic-hyperthermia elevated protein carbonyls (P = 0.018), a response not observed with hypertonic-hyperthermia. In SOL muscles, isotonic-hyperthermia also increases resting tension (P < 0.001); however, these effects were eliminated in hypertonic-hyperthermia. Unlike EDL, there were no effects of hyperthermia and/or hyperosmolality on sarcolemmal injury or protein carbonyls. Osmolality selectively modifies skeletal muscle response to hyperthermia in this model. Fast-glycolytic muscle appears particularly vulnerable to isotonic-hyperthermia, resulting in elevated muscle tension, sarcolemmal injury and protein oxidation; whereas slow-oxidative muscle exhibits increased tension but no injury or protein oxidation under the conditions and duration tested.

Gga-miR-205a Affecting Myoblast Proliferation and Differentiation by Targeting CDH11

Non-coding RNAs especially miRNAs have been found to play important roles during skeletal muscle development. Our previous RNA-Seq performed on breast muscle tissue from 7 weeks old Recessive White Rock and Xinhua Chicken and leg muscle tissue from female Xinghua Chicken at three development time points (11 embryo age, 16 embryo age, and 1 day post hatch) (accession number GSE62971 and GSE89355, respectively) showed that miR-205a and CDH11 were differentially expressed genes. In this study, we found that overexpression of CDH11 significantly facilitated Quail muscle clone (QM7) and chicken primary myoblast (CPM) proliferation and hampered CPM differentiation. MiR-205a can directly binding to the 3'UTR of CDH11 and the overexpression of miR-205a could inhibit both cell lines (QM7) and CPM proliferation, at the meantime promote the differentiation of myoblasts. The Dual-Luciferase Reporter Assay results and qRT-PCR results showed that myogenin (MyoG) could regulate the expression of miR-205a by binding to the active region of miR-205a. Altogether our data suggest that MyoG could stimulate miR-205a expression to suppress CDH11, which promotes myoblasts proliferation while represses the differentiation.

Tart cherry concentrate does not enhance muscle protein synthesis response to exercise and protein in healthy older men

BACKGROUND

Oxidative stress and inflammation may contribute to anabolic resistance in response to protein and exercise in older adults. We investigated whether consumption of montmorency cherry concentrate (MCC) increased anabolic sensitivity to protein ingestion and resistance exercise in healthy older men.

METHODS

Sixteen healthy older men were randomized to receive MCC (60 mL·d^-1) or placebo (PLA) for two weeks, after baseline measures in week 1. During week 3, participants consumed 10 g whey protein·d^-1 and completed three bouts of unilateral leg resistance exercise (4 × 8-10 repetitions at 80% 1RM). Participants consumed a bolus (150 mL) and weekly (50 mL) doses of deuterated water. Body water ²H enrichment was measured in saliva and vastus lateralis biopsies were taken from the non-exercised leg after weeks 1, 2 and 3, and the exercised leg after week 3, to measure tracer incorporation at rest, in response to protein and protein + exercise.

RESULTS

Myofibrillar protein synthesis increased in response to exercise + protein compared to rest (p < 0.05) in both groups, but there was no added effect of supplement (MCC: 1.79 ± 0.75 EX vs 1.15 ± 0.40 rest; PLA: 2.22 ± 0.54 vs 1.21 ± 0.18; all %·d^-1). Muscle total NFĸB protein was decreased with exercise and protein in MCC (NFĸB: -20.7 ± 17.5%) but increased in PLA (NFĸB: 17.8 ± 31.3%, p = 0.073).

CONCLUSION

Short-term MCC ingestion does not affect the anabolic response to protein and exercise in healthy, relatively active, older men, despite MCC ingestion attenuating expression of proteins involved in the muscle inflammatory response to exercise, which may influence the chronic training response.

Assessing the mechanistic target of rapamycin complex-1 pathway in response to resistance exercise and feeding in human skeletal muscle by multiplex assay

The mechanistic target of rapamycin complex-1 (mTORC-1) is a key nutrient and contraction-sensitive protein that regulates a pathway leading to skeletal muscle growth. Utilizing a multiplex assay, we aimed to examine the phosphorylation status of key mTORC-1-related signalling molecules in response to protein feeding and resistance exercise. Eight healthy men (age, 22.5 ± 3.1 years; mass, 80 ± 9 kg; 1-repetition maximum leg extension, 87 ± 5 kg) performed 4 sets of unilateral leg extensions until volitional failure. Immediately following the final set, all participants consumed a protein-enriched beverage. A single skeletal muscle biopsy was obtained from the vastus lateralis before (Pre) with further bilateral biopsies at 1 h (1 h exercised legs (FEDEX) and 1 h nonexercised legs (FED)) and 3 h (3 h FEDEX and 3 h FED) after drink ingestion. Phosphorylated Akt^Ser473 was significantly elevated from Pre at 1 h FEDEX. Phosphorylated p70S6K1^Thr412 was significantly increased above Pre at 1 h FEDEX and 1 h FED and was still significantly elevated at 3 h FEDEX but not 3 h FED. Phosphorylated rpS6^Ser235/236 was also significantly increased above Pre at 1 h FEDEX and 1 h FED with 1 h FEDEX greater than 1 h FED. Our data highlight the utility of a multiplex assay to assess anabolic signalling molecules in response to protein feeding and resistance exercise in humans. Importantly, these changes are comparable with those as previously reported using standard immunoblotting and protein activity assays.

Effect of QSOX1 on cattle carcass traits as well as apoptosis and triglyceride production in bovine fetal fibroblasts and mammary epithelial cells

QSOX1 (quiescin-sulfhydryl oxidase 1) is involved in various processes, including apoptosis and the development of breast diseases. Here, we investigated the effect of QSOX1 on the meat quality of Simmental cattle by analyzing the correlation between QSOX1 single nucleotide polymorphisms (SNPs), I2 204 C>T and I2 378 C>T, and certain meat quality traits. The effects of QSOX1 on triglyceride synthesis and cell apoptosis were further validated by gene silencing or overexpression in bovine fetal fibroblasts and mammary epithelial cells. The results showed that I2 204 C>T and I2 378 C>T had significant correlations with loin thickness, hind hoof weight, fat coverage, liver weight, heart weight, marbling and back fat thickness (P<0.05). QSOX1 overexpression also increased triglyceride production and suppressed apoptosis. In summary, QSOX1 is an important factor for meat quality, lipid metabolism, and cell apoptosis, indicating that QSOX1 could be used as a biomarker to assist in breeding cattle with superior meat.

A Flowthrough Assay for Rapid Bedside Stratification of Bloodstream Bacterial Infection in Critically Ill Patients: a Pilot Study

Bacterial infections affect more than 2 million people annually. Of these, systemic infections caused by bacteria in critically ill patients may lead to life-threatening conditions such as sepsis. We have developed a point-of-care (POC) device called Septiflo that can detect and stratify the Gram status of bloodstream bacterial infections in less than 10 min from a drop of human plasma. It works on the principle of identifying pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharides (LPS) and lipoteichoic acid (LTA) that are released into the bloodstream at the onset of Gram-negative and Gram-positive bacterial infections, respectively. The biomarkers are captured on a membrane without a receptor, and the Gram status specificity is conferred by the ligands attached to gold nanoparticles (AuNPs) used as signal amplification probes. The ultrasensitive colorimetric results are read by eye down to a 100-fg/ml detection limit without an instrument. No cross-interference between the PAMPs is seen during Gram stratification. Septiflo results also display better performance than commercial enzyme-linked immunosorbent assays (ELISAs). Tests performed on 60 clinical samples from patients showed a correlation accuracy of 70% against procalcitonin (PCT), an accepted surrogate biomarker for sepsis. A direct comparison with eubacterial PCR yielded up to 94% accuracy in 31 patients at a chosen cutoff level for LPS and LTA and area under the curve (AUC) values of 0.927 and 0.885, respectively, though blood culture was negative for most samples. The high sensitivity, low cost, and simple bedside utility of the assay may aid in better sepsis management apparently at the presymptomatic stage, lowering empirical therapy, medical costs, antimicrobial resistance, and mortality.

Transcriptome signatures of p,p´-DDE-induced liver damage in Mus spretus mice

The use of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane) in some countries, although regulated, is contributing to an increased worldwide risk of exposure to this organochlorine pesticide or its derivative p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene]. Many studies have associated p,p'-DDE exposure to type 2 diabetes, obesity and alterations of the reproductive system, but their molecular mechanisms of toxicity remain poorly understood. We have addressed this issue by using commercial microarrays based on probes for the entire Mus musculus genome to determine the hepatic transcriptional signatures of p,p'-DDE in the phylogenetically close mouse species Mus spretus. High-stringency hybridization conditions and analysis assured reliable results, which were also verified, in part, by qRT-PCR, immunoblotting and/or enzymatic activity. Our data linked 198 deregulated genes to mitochondrial dysfunction and perturbations of central signaling pathways (kinases, lipids, and retinoic acid) leading to enhanced lipogenesis and aerobic glycolysis, inflammation, cell proliferation and testosterone catabolism and excretion. Alterations of transcript levels of genes encoding enzymes involved in testosterone catabolism and excretion would explain the relationships established between p,p´-DDE exposure and reproductive disorders, obesity and diabetes. Further studies will help to fully understand the molecular basis of p,p´-DDE molecular toxicity in liver and reproductive organs, to identify effective exposure biomarkers and perhaps to design efficient p,p'-DDE exposure counteractive strategies.

Effects of phthalates on normal human breast cells co-cultured with different fibroblasts

Whether or not phthalates play a role in breast carcinogenesis remains to be determined. The goal of this study was to explore the effects of phthalates on the growth of normal MCF-10A breast cells modulated by breast fibroblasts. Fibroblasts were derived from normal mammary tissue adjacent to both estrogen receptor (ER) positive and negative primary breast cancers, which were grown separately from nontumorigenic MCF-10A epithelial cells. MCF-10A co-culture cells were treated with 10 nM 17β-estradiol (E₂), Butyl benzyl phthalate (BBP), di(n-butyl) phthalate (DBP), and di(20ethylhexyl) phthalate (DEHP) (10 and 100 nM). After incubation for 120 hours, the cells were harvested and extracted for MTT assay. Western blot analysis was used to evaluate the proliferative pathway proteins and the effects on ER α. Only fibroblasts from ER (+) breast cancer significantly stimulated proliferation of MCF-10A cells. Exposure of the co-culture to E₂, BBP, DBP, DEHP, and E₂ combined with one of these phthalates resulted in significantly increased cell proliferation, as well as proliferating cell nuclear antigen (PCNA) and ER α expressions. The present study demonstrates that phthalates express a significant influence in fibroblast–epithelial interactions, similarly to the effects of E₂ on breast cells. The effects of phthalates on normal breast cells depend upon ER modulating actions. In breast carcinogenesis, phthalates should be considered as having endocrine disrupting potential, even at low concentrations.

Skeletal Muscle Pyruvate Dehydrogenase Phosphorylation and Lactate Accumulation During Sprint Exercise in Normoxia and Severe Acute Hypoxia: Effects of Antioxidants

Compared to normoxia, during sprint exercise in severe acute hypoxia the glycolytic rate is increased leading to greater lactate accumulation, acidification, and oxidative stress. To determine the role played by pyruvate dehydrogenase (PDH) activation and reactive nitrogen and oxygen species (RNOS) in muscle lactate accumulation, nine volunteers performed a single 30-s sprint (Wingate test) on four occasions: two after the ingestion of placebo and another two following the intake of antioxidants, while breathing either hypoxic gas (P_IO₂ = 75 mmHg) or room air (P_IO₂ = 143 mmHg). Vastus lateralis muscle biopsies were obtained before, immediately after, 30 and 120 min post-sprint. Antioxidants reduced the glycolytic rate without altering performance or VO₂. Immediately after the sprints, Ser²⁹³- and Ser³⁰⁰-PDH-E1α phosphorylations were reduced to similar levels in all conditions (~66 and 91%, respectively). However, 30 min into recovery Ser²⁹³-PDH-E1α phosphorylation reached pre-exercise values while Ser³⁰⁰-PDH-E1α was still reduced by 44%. Thirty minutes after the sprint Ser²⁹³-PDH-E1α phosphorylation was greater with antioxidants, resulting in 74% higher muscle lactate concentration. Changes in Ser²⁹³ and Ser³⁰⁰-PDH-E1α phosphorylation from pre to immediately after the sprints were linearly related after placebo (r = 0.74, P < 0.001; n = 18), but not after antioxidants ingestion (r = 0.35, P = 0.15). In summary, lactate accumulation during sprint exercise in severe acute hypoxia is not caused by a reduced activation of the PDH. The ingestion of antioxidants is associated with increased PDH re-phosphorylation and slower elimination of muscle lactate during the recovery period. Ser²⁹³ re-phosphorylates at a faster rate than Ser³⁰⁰-PDH-E1α during the recovery period, suggesting slightly different regulatory mechanisms.

A new background subtraction method for Western blot densitometry band quantification through image analysis software

Since its first description, Western blot has been widely used in molecular labs. It constitutes a multistep method that allows the detection and/or quantification of proteins from simple to complex protein mixtures. Western blot quantification method constitutes a critical step in order to obtain accurate and reproducible results. Due to the technical knowledge required for densitometry analysis together with the resources availability, standard office scanners are often used for the imaging acquisition of developed Western blot films. Furthermore, the use of semi-quantitative software as ImageJ (Java-based image-processing and analysis software) is clearly increasing in different scientific fields. In this work, we describe the use of office scanner coupled with the ImageJ software together with a new image background subtraction method for accurate Western blot quantification. The proposed method represents an affordable, accurate and reproducible approximation that could be used in the presence of limited resources availability.

Expression of Glial Cell Line-Derived Neurotrophic Factor (GDNF) and the GDNF Family Receptor Alpha Subunit 1 in the Paravaginal Ganglia of Nulliparous and Primiparous Rabbits

PURPOSE

To evaluate the expression of glial cell line-derived neurotrophic factor (GDNF) and its receptor, GDNF family receptor alpha subunit 1 (GFRα-1) in the pelvic (middle third) vagina and, particularly, in the paravaginal ganglia of nulliparous and primiparous rabbits.

METHODS

Chinchilla-breed female rabbits were used. Primiparas were killed on postpartum day 3 and nulliparas upon reaching a similar age. The vaginal tracts were processed for histological analyses or frozen for Western blot assays. We measured the ganglionic area, the Abercrombie-corrected number of paravaginal neurons, the cross-sectional area of the neuronal somata, and the number of satellite glial cells (SGCs) per neuron. The relative expression of both GDNF and GFRα-1 were assessed by Western blotting, and the immunostaining was semiquantitated. Unpaired two-tailed Student t -test or Wilcoxon test was used to identify statistically significant differences (P≤0.05) between the groups.

RESULTS

Our findings demonstrated that the ganglionic area, neuronal soma size, Abercrombie-corrected number of neurons, and number of SGCs per neuron were similar in nulliparas and primiparas. The relative expression of both GDNF and GFRα-1 was similar. Immunostaining for both GDNF and GFRα-1 was observed in several vaginal layers, and no differences were detected regarding GDNF and GFRα-1 immunostaining between the 2 groups. In the paravaginal ganglia, the expression of GDNF was increased in neurons, while that of GFRα-1 was augmented in the SGCs of primiparous rabbits.

CONCLUSIONS

The present findings suggest an ongoing regenerative process related to the recovery of neuronal soma size in the paravaginal ganglia, in which GDNF and GFRα-1 could be involved in cross-talk between neurons and SGCs.

Guidelines for authors and reviewers on antibody use in physiology studies

Antibody use is a critical component of cardiovascular physiology research, and antibodies are used to monitor protein abundance (immunoblot analysis) and protein expression and localization (in tissue by immunohistochemistry and in cells by immunocytochemistry). With ongoing discussions on how to improve reproducibility and rigor, the goal of this review is to provide best practice guidelines regarding how to optimize antibody use for increased rigor and reproducibility in both immunoblot analysis and immunohistochemistry approaches.

Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/guidelines-on-antibody-use-in-physiology-studies/.

Western blot analysis of cells encapsulated in self-assembling peptide hydrogels

Continuous optimization of in vitro analytical techniques is ever more important, especially given the development of new materials for tissue engineering studies. In particular, isolation of cellular components for downstream applications is often hindered by the presence of biomaterials, presenting a major obstacle in understanding how cell–matrix interactions influence cell behavior. Here, we describe an approach for western blot analysis of cells that have been encapsulated in self-assembling peptide hydrogels (SAPHs), which highlights the need for complete solubilization of the hydrogel construct. We demonstrate that both the choice of buffer and multiple cycles of sonication are vital in obtaining complete solubilization, thereby enabling the detection of proteins otherwise lost to SAP aggregation. Moreover, we show that the presence of self-assembling peptides (SAPs) does not interfere with the standard immunoblotting technique, offering the potential for use in more full-scale proteomic studies.

Severe energy deficit upregulates leptin receptors, leptin signaling, and PTP1B in human skeletal muscle

In obesity, leptin receptors (OBR) and leptin signaling in skeletal muscle are downregulated. To determine whether OBR and leptin signaling are upregulated with a severe energy deficit, 15 overweight men were assessed before the intervention (PRE), after 4 days of caloric restriction (3.2 kcal·kg body wt−1·day−1) in combination with prolonged exercise (CRE; 8 h walking + 45 min single-arm cranking/day) to induce an energy deficit of ~5,500 kcal/day, and following 3 days of control diet (isoenergetic) and reduced exercise (CD). During CRE, the diet consisted solely of whey protein ( n = 8) or sucrose ( n = 7; 0.8 g·kg body wt−1·day−1). Muscle biopsies were obtained from the exercised and the nonexercised deltoid muscles and from the vastus lateralis. From PRE to CRE, serum glucose, insulin, and leptin were reduced. OBR expression was augmented in all examined muscles associated with increased maximal fat oxidation. Compared with PRE, after CD, phospho-Tyr1141OBR, phospho-Tyr985OBR, JAK2, and phospho-Tyr1007/1008JAK2 protein expression were increased in all muscles, whereas STAT3 and phospho-Tyr705STAT3 were increased only in the arms. The expression of protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle was increased by 18 and 45% after CRE and CD, respectively ( P < 0.05). Suppressor of cytokine signaling 3 (SOCS3) tended to increase in the legs and decrease in the arm muscles (ANOVA interaction: P < 0.05). Myosin heavy chain I isoform was associated with OBR protein expression ( r = −0.75), phospho-Tyr985OBR ( r = 0.88), and phospho-Tyr705STAT3/STAT3 ( r = 0.74). In summary, despite increased PTP1B expression, skeletal muscle OBR and signaling are upregulated by a severe energy deficit with greater response in the arm than in the legs likely due to SOCS3 upregulation in the leg muscles.

NEW & NOTEWORTHY This study shows that the skeletal muscle leptin receptors and their corresponding signaling cascade are upregulated in response to a severe energy deficit, contributing to increase maximal fat oxidation. The responses are more prominent in the arm muscles than in the legs but partly blunted by whey protein ingestion and high volume of exercise. This occurs despite an increase of protein tyrosine phosphatase 1B protein expression, a known inhibitor of insulin and leptin signaling.