Alcoholic hepatitis (AH) continues to be a disease with high mortality and no efficacious medical treatment. Although severe AH is presented as acute on chronic liver failure, what underlies this ...transition from chronic alcoholic steatohepatitis (ASH) to AH is largely unknown. To address this question, unbiased RNA sequencing and proteomic analyses were performed on livers of the recently developed AH mouse model, which exhibits the shift to AH from chronic ASH upon weekly alcohol binge, and these results are compared to gene expression profiling data from AH patients. This cross‐analysis has identified Casp11 (CASP4 in humans) as a commonly up‐regulated gene known to be involved in the noncanonical inflammasome pathway. Immunoblotting confirms CASP11/4 activation in AH mice and patients, but not in chronic ASH mice and healthy human livers. Gasdermin‐D (GSDMD), which induces pyroptosis (lytic cell death caused by bacterial infection) downstream of CASP11/4 activation, is also activated in AH livers in mice and patients. CASP11 deficiency reduces GSDMD activation, bacterial load in the liver, and severity of AH in the mouse model. Conversely, the deficiency of interleukin‐18, the key antimicrobial cytokine, aggravates hepatic bacterial load, GSDMD activation, and AH. Furthermore, hepatocyte‐specific expression of constitutively active GSDMD worsens hepatocellular lytic death and polymorphonuclear leukocyte inflammation. Conclusion: These results implicate pyroptosis induced by the CASP11/4‐GSDMD pathway in the pathogenesis of AH. (Hepatology 2018;67:1737‐1753).
A 73-year-old woman complaining of cough and dyspnea was admitted to our hospital. High-resolution computed tomography chest revealed patchy ground-glass attenuation in the upper lung field. The ...patient suffered an asthma attack and was diagnosed with allergic pneumonitis; prednisolone was administered for treatment. Bird-related hypersensitivity pneumonitis was suspected, as she had a gray parrot (Psittacus erithacus) and a budgerigar (Melopsittacus undulatus) at home. An immunoblotting analysis with the patient's serum demonstrated IgG-binding fractions to the gray parrot's feathers only; no binding was noted with the budgerigar antigens. The patient was conclusively diagnosed with hypersensitivity pneumonitis related to exposure to a gray parrot.
We developed a nonradioactive fluorescence-activated cell sorting-based assay, called surface sensing of translation (SUnSET), which allows the monitoring and quantification of global protein ...synthesis in individual mammalian cells and in heterogeneous cell populations. We demonstrate here, using mouse dendritic and T cells as a model, that SUnSET offers a technical alternative to classical radioactive labeling methods for the study of mRNA translation and cellular activation.
The actions and regulation of cardiomyocyte β
1
ARs
differ in several respects from the properties described for the prototypical
β
2
AR subtype; a mechanism to explain the unique properties
of the β
...1
AR subtype has never been obvious. This viewpoint
summarizes recent studies that identify a novel signaling paradigm for the
β
1
AR, implicating the N-terminus as a molecular
determinant of β
1
AR responsiveness.
Microtubule-associated protein light chain 3 (LC3) is now widely used to monitor autophagy. One approach is to detect LC3 conversion (LC3-I to LC3-II) by immunoblot analysis because the amount of ...LC3-II is clearly correlated with the number of autophagosomes. However, LC3-II itself is degraded by autophagy, making interpretation of the results of LC3 immunoblotting problematic. Furthermore, the amount of LC3 at a certain time point does not indicate autophagic flux, and therefore, it is important to measure the amount of LC3-II delivered to lysosomes by comparing LC3-II levels in the presence and absence of lysosomal protease inhibitors. Another problem with this method is that LC3-II tends to be much more sensitive to be detected by immunoblotting than LC3-I. Accordingly, simple comparison of LC3-I and LC3-II, or summation of LC3-I and LC3-II for ratio determinations, may not be appropriate, and rather, the amount of LC3-II can be compared between samples.
α-Synuclein is a key molecule in understanding the pathogenesis of neurodegenerative α-synucleinopathies such as Parkinson's disease. Despite extensive research, however, its precise function remains ...unclear partly because of a difficulty in immunoblotting detection of endogenous α-synuclein. This difficulty has largely restricted the progress for α-synucleinopathy research. Here, we report that α-synuclein monomers tend to easily detach from blotted membranes, resulting in no or very poor detection. To prevent this detachment, a mild fixation of blotted membranes with paraformaldehyde was applied to the immunoblotting method. Amazingly, this fixation led to clear and strong detection of endogenous α-synuclein, which has been undetectable by a conventional immunoblotting method. Specifically, we were able to detect endogenous α-synuclein in various human cell lines, including SH-SY5Y, HEK293, HL60, HeLa, K562, A375, and Daoy, and a mouse cell line B16 as well as in several mouse tissues such as the spleen and kidney. Moreover, it should be noted that we could clearly detect endogenous α-synuclein phosphorylated at Ser-129 in several human cell lines. Thus, in some tissues and cultured cells, endogenous α-synuclein becomes easily detectable by simply fixing the blotted membranes. This improved immunoblotting method will allow us to detect previously undetectable endogenous α-synuclein, thereby facilitating α-synuclein research.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Immunoblotting is a powerful technique for the semi-quantitative analysis of ubiquitylation events, and remains the most commonly used method to study this process due to its high specificity, speed, ...sensitivity and relatively low cost. However, the ubiquitylation of proteins is complex and, when the analysis is performed in an inappropriate manner, it can lead to the misinterpretation of results and to erroneous conclusions being reached. Here we discuss the advantages and disadvantages of the methods currently in use to analyse ubiquitin chains and protein ubiquitylation, and describe the procedures that we have found to be most useful for optimising the quality and reliability of the data that we have generated. We also highlight commonly encountered problems and the pitfalls inherent in some of these methods. Finally, we introduce a set of recommendations to help researchers obtain high quality data, especially those new to the field of ubiquitin signalling. The specific topics addressed in this article include sample preparation, the separation, detection and identification of particular ubiquitin chains by immunoblotting, and the analysis of ubiquitin chain topology through the combined use of ubiquitin-binding proteins and ubiquitin linkage-specific deubiquitylases.
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