RIPA Buffer Research Articles

Single-cell differential detergent fractionation for detection of cytokeratin 8 proteoforms.

Simultaneous profiling of proteoforms and nucleic acids at the single-cell level, i.e., multi omics, directly links the central dogma. However, current single-cell approaches are limited in their ability to identify proteoforms while preserving the nucleus for further analysis. This limitation is especially pronounced in proteins where their proteoforms present diverse biological functions such as cytokeratin 8 (CK8), which, while commonly known for its structural role, is also involved in several diseases. Here, we present a single-cell western blot (scWB) integrated with differential detergent fractionation (DDF) to selectively solubilize and separate CK8 proteoforms while preserving nuclear integrity for subsequent nucleus-based assays. We report on assay development, including screening a panel of lysis buffers based on nonionic detergents and electrophoresis conditions to achieve a separation resolution between two proteoforms of up to 0.94 with an electric field of 30 V/cm, while preserving an intact nucleus. The cytoplasm-specific lysis approach (DDF buffer) demonstrated comparable solubilization efficiency to whole-cell solubilization (RIPA buffer), achieving proteoform solubilization in 14.3% and 10.3% of solubilized cells using DDF and RIPA buffers, respectively, while keeping the nucleus intact. To understand the broad applicability of the assay conditions, we scrutinized electrophoresis performance for resolving CK8 proteoforms across a panel of widely used breast cancer cell lines (MCF7, SKBR3, and MDA-MB-231), showing presence of proteoforms only in MCF7. Our approach allows for tailored solubilization, achieving reliable proteoform detection and nuclear retention across different cell types. Proteoform profiling at the single-cell level forms a basis for the exploration of the role of specific CK8 molecular forms in cellular processes.

Robust assessment of sample preparation protocols for proteomics of cells and tissues

In proteomic studies, the reliability and reproducibility of results hinge on well-executed protein extraction and digestion protocols. Here, we systematically compared three established digestion methods for macrophages, namely filter-assisted sample preparation (FASP), in-solution, and in-gel digestion protocols. We also compared lyophilization and manual lysis for liver tissue protein extraction, each of them tested using either sodium deoxycholate (SDC)- or RIPA-based lysis buffer. For the macrophage cell line, FASP using passivated filter units outperformed the other tested methods regarding the number of identified peptides and proteins. However, a careful standardization has shown that all three methods can yield robust results across a wide range of starting material (even starting with 1 μg of proteins). Importantly, inter and intra-day coefficients of variance (CVs) were determined for all sample preparation protocols. Thus, the median inter-day CVs for in-solution, in-gel and FASP protocols were respectively 10, 8 and 9%, very similar to the median CVs obtained for the intra-day analysis (9, 8 and 8%, respectively). Moreover, FASP digestion presented 80% of proteins with a CV lower than 25%, followed closely by in-gel digestion (78%) and in-solution sample preparation (72%) protocols. For tissue proteomics, both manual lysis and lyophilization presented similar proteome coverage and reproducibility, but the efficiency of protein extraction depended on the lysis buffer used, with RIPA buffer showing better results. In conclusion, although each sample preparation method has its own particularity, they are all suited for successful proteomic experiments if a careful standardization of the sample preparation workflow is carried out.

P021 Higher TNFα and IL-6 mucosal levels in ulcerative colitis patients with more severe endoscopic activity

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterised by colonic mucosa inflammation. Its clinical course is marked by alternating periods of relapse and remission that impair patients' quality of life. In the last decades, novel therapies have shown to be effective for UC resulting in lower rates of colectomy. However, there is still a significant proportion of non-responding patients that change from one treatment to another, being exposed to its potential adverse events. Thus, predictive factors of response to available drugs are needed to tailor the best treatment strategy for each patient. The aim of our study was to measure TNFα and IL-6 levels in colonic biopsies from patients with UC with moderate to severe endoscopic activity. Methods A prospective, observational single-centre study was designed and it is currently on going. Adult UC patients with moderate to severe endoscopic activity (Mayo Endoscopic Score (MES) > 1) in a routine colonoscopy were included. Biopsies from inflamed (MES>1) and non-inflamed (MES=0) colon of each patient were homogenised and processed by using RIPA buffer and ultrasounds to obtain cell lysates. Human Luminex Discovery Assay (2 plex) was used for the simultaneous detection and quantitation of IL-6 and TNFα. Data are shown as percentage, median, interquartile range (IQR) and mean ± standard deviation (SD) as appropriate. Results So far, 21 patients were consecutively included (mean age 53.8 years (SD 17.0), 52.4% female). About 43% of patients had left-sided UC, 28.5% extensive UC and 28.5% proctitis. Regarding endoscopic activity, 61.9% of patients showed MES=2 and 38.1% were MES=3. Fourteen patients (66.6%) were bio-naïve and 7 (33.3%) had been exposed to anti-TNFα. IL-6 was detected in biopsies from colon with MES ≥ 2 of 18 (85.7%) patients, of which 10 (55.6%) patients also TNFα was found. Neither IL-6 nor TNFα were detected in biopsies from non-inflamed colon (p=0.00). Median IL-6 in inflamed colonic samples from patients with MES-2 was 25.6pg/ml (IQR 0.2-74.3) and 92.2pg/ml (IQR 16.9-314.3) in those with MES-3 (p=0.09). Median TNFα in inflamed colonic biopsies from patients with MES-2 was 0.0pg/ml (IQR 0.0-20.0) and 22.2pg/ml (IQR 0.0-34.3) in patients with MES-3 (p=0.12) (Figure 1). No differences were found in TNFα levels between anti-TNFα naïve patients and those patients previously exposed to anti-TNFα (p=0.96). Conclusion IL-6 and TNFα are elevated in inflamed colonic mucosa, particularly in those patients with more severe endoscopic activity, while they are not found in non-inflamed colonic mucosa. The correlation between cytokine levels and endoscopic severity suggests their potential as biomarkers for treatment response.

An Efficient Protein Extraction Method from Astragalus armatus Willd. Roots for Proteomic Analysis

Abstract The first step of the proteomic study is the extraction and the success of this technique was based mainly on the choice of the best extraction. The purpose of this study was to determine the simplest and lowest-cost method of total protein extraction. Initially, various extraction methods were performed for protein extraction from roots of Astragalus armatus Willd. The methods employed were extraction by RIPA buffer, hypotonic buffer and distilled water. After determination of protein concentration by Bradford method and SDS PAGE electrophoretic analysis, the quantity and quality of extracted proteins using different protocols from A. armatus were determined and compared. The protein yield of RIPA buffer method was higher than the yields of hypotonic buffer method and distilled water method. The best protein patterns were produced by RIPA buffer method. The extract obtained by RIPA buffer was the optimal protocol for protein extraction.

Critical evaluation of cell lysis methods for metallodrug studies in cancer cells.

Intracellular accumulation studies are a key step in metallodrug development but often variable results are obtained. Therefore, we aimed here to investigate different protocols for efficient and reproducible lysis of cancer cells in terms of protein content in lysates and in cell uptake studies of the Ru anticancer complex [chlorido(8-oxyquinolinato)(η6-p-cymene)ruthenium(II)] ([Ru(cym)(HQ)Cl]). The physical lysis methods osmosis and sonication were chosen for comparison with chemical lysis with the radioimmunoprecipitation assay (RIPA) buffer. Based on the protein content and the total Ru accumulated in the lysates, the latter determined using inductively coupled plasma-mass spectrometry, RIPA buffer was the most efficient lysis method. Measurements of plastic adsorption blanks revealed that the higher Ru content determined in the RIPA buffer lysis samples may be due a higher amount of Ru extracted from the plastic incubation plates compared with osmosis and sonication. Overall, we found that the choice of lysis method needs to be matched to the information sought and we suggest the least disruptive osmosis method might be the best choice for labile drug-biomolecule adducts. Minimal differences were found for experiments aimed at measuring the overall cell uptake of the Ru complex.

P-085 Reactive molecules drive sperm capacitation via protein posttranslational modifications

Abstract Study question Are S-sulfenylation and S-nitrosylation, two essential posttranslational modifications (PTMs), increased during sperm capacitation? Which proteins are subjected to S-sulfenylation? Summary answer S-sulfenylation and S-nitrosylation increase during sperm capacitation. S-sulfenylation affects certain proteins, including A-kinase anchor protein 13, Fibrilline-1, and Spermatogenesis-associated protein 7. What is known already There is a significant increase in reactive oxygen species (ROS) and reactive nitrogen species (RNS) production within sperm capacitation. In contrast to tyrosine phosphorylation, a well-established mark of sperm capacitation, ROS, and RNS lead to PTMs themselves and modify thiol groups of cysteines. Despite these facts, the dynamics of ROS/RNS-derived PTMs during sperm capacitation remain unknown. Therefore, we consider both S-nitrosylation and S-sulfenylation of sperm proteins as novel modifications associated with the capacitation. Study design, size, duration C57BL6 mouse sperm were isolated from the caudae epididymae of 12-20-week-old males (n = 5). The study compared non-capacitated and capacitated spermatozoa using proteomic profiling. Participants/materials, setting, methods Sperm proteins were extracted into RIPA buffer. The protein lysate was incubated with 5mM dimedone, a hapten that specifically labels S-sulfenylated proteins, and immunogenically detected with an anti-dimedone antibody (Merk, Germany). Alternatively, S-nitrosylated proteins were detected by the anti-nitrosocysteine antibody (Merk, Germany). S-sulfenylated and S-nitrosylated proteins were visualized by western blotting. S-sulfenylated proteins were simultaneously identified by mass spectrometry. Main results and the role of chance We demonstrated an increase in S-sulfenylation and S-nitrosylation along with sperm capacitation. In addition, both S-sulfenylation and S-nitrosylation are positively correlated with tyrosine phosphorylation. Using mass spectrometry, we identified S-sulfenylated proteins, mostly belonging to the cytoskeleton: A-kinase anchor protein 13, Fibrilline-1, Spermatogenesis-associated protein 7, and Rab-like protein 2A. Limitations, reasons for caution The limitation of this study is the instability of PTMs. ROS/RNS-derived PTMs hypothetically arise and cease during protein sample preparation. The experiment was limited to one animal model. Further experiments should be performed on other mammalian models. Wider implications of the findings Studying novel sperm PTMs and their mechanism of action may improve the diagnosis of male infertility. Further, it could bring a novel approach to modulate the fertilizing ability of sperm used for in vitro fertilization. Trial registration number 260 536

Integrated Mass Spectrometry‐based Pipeline for Characterization of Tau in Human Alzheimer’s Brain: Development and Comparison of Sample Preparation Methods

AbstractBackgroundTau protein aggregation into neurofibrillary tangles in the brain is a pathological hallmark of Alzheimer’s disease (AD) and related tauopathies [1]. Though the mechanism of tau destabilization is not fully understood, tau protein exhibits several allele‐specific isoforms and post‐translational modifications (PTMs) specific to tau aggregates [2]. To explore in‐depth tau species in brain tissues of AD patients, we developed novel pipelines based on different tau fractions retrieved by buffer solubility, Filter Aided Sample Preparation (FASP) or immunoprecipitation, before high‐resolution mass spectrometry (HRMS) analysis.MethodAs a proof of concept, we used frozen brain samples from two AD patients (0.6‐1.2 g per replicate, middle frontal gyrus). The samples were divided and homogenized, ultracentrifuged at 180.000xg for 30min and solubilized in different buffers successively (2 replicates): (1) SarkMethodlow‐salt buffer, 10% Triton X‐100, sarkosyl buffer, and urea buffer; (2) RIPAMethodhigh‐salt buffer (twice), RIPA buffer and urea buffer; and, (3) GnHMethodguanidine hydrochloride and urea buffer. Then, we performed an antibody‐free approach by FASP or immunoprecipitation with a panel of commercial tau antibodies and analyzed on reversed‐phase capillary liquid chromatography, coupled with a qExactive HRMS.ResultHRMS demonstrated that the RIPA method performed better than the other methods for Tau analysis: coverage of 63% (full‐length, 2N4R) and 342 tau peptide‐spectrum matches (PSMs) (Sark: 49% and 183 PSMs; GnH: 41% and 169 PSMs). PTM‐modified tau species (phosphorylated, methylated, and acetylated) were primarily seen using the RIPA method (59 PSMs; Sark: 19 PSMs, GnH: 21 PSMs). Immunoprecipitation improved tau coverage and PTM detection compared to FASP.ConclusionThese findings highlight the best performance of the RIPA method followed by immunoprecipitation for the study of AD brain tau allele‐specific isoforms and PTMs using HRMS. Better characterization of Tau molecular profile in the brain of AD patients opens the gate for a better understanding of AD pathogenesis and represents an opportunity in the biomarker field.[1] Mroczko, B. et al. Int J Mol Sci 2019, 20, E4661, https://doi.org/10.3390/ijms20194661.[2] Boyarko, B.; Hook, V. Front. Neurosci. 2021, 15, 702788, https://doi.org/10.3389/fnins.2021.702788.

The Final Pathway of Carbohydrate Oxidation: Revisiting the mLOC

The confirmation of the Intracellular Lactate Shuttle proposed by Brooks and colleagues in 1998 revolutionized the way lactate metabolism was studied in the field of exercise physiology, nutrition, metabolism, and medicine. Previous investigations identified the structure of the mitochondrial Lactate Oxidation Complex (mLOC) which includes MCT1, LDH, COX4, and CD147. While the predominant view in research and textbooks was that pyruvate was imported into the mitochondria to be oxidized it wasn’t until 2009 that Jiang and Colleagues elucidated the mitochondrial pyruvate carrier (mPC). Knowing this, many researchers developed their questions around either pyruvate or lactate metabolism, which may have led to confusion in the field since both substrates play an important role in carbohydrate oxidation. This dilemma led us to the hypothesis that the mPC is in fact an extended member of the mLOC. Mixed skeletal muscle and liver were excised and whole blood was collected post-mortem from (n=5) 4-month-old C57B/l6 mice. Tissues were homogenized in an isotonic solution supplemented with a protease and phosphatase inhibitor. Blood was resuspended in H2O to rupture the cell membranes and the lysates (RBC) were used as negative controls. Mitochondria were isolated by differential centrifugation and resuspended in RIPA buffer. Protein concentrations of tissues were determined using a BCA standard. Western blotting was performed by loading 20 ug of each lysate, separated on an SDS-PAGE gel, and transferred to a PVDF membrane. Membranes were blocked and probed for MCT1(1:1000), mPC1 (1:500), COX4(1:1000), LDHA (1:1000). An SDS-PAGE was repeated and the mPC was excised from the gel. A trypsin digest was performed to isolate the peptides and then analyzed by one-dimensional LCMS/MS at the UC Berkeley QB3 proteomics/mass spectrometry lab. For cDNA preparation, RNA was extracted from 15 mg of skeletal muscle using the Qiagen RNeasy Fibrous tissue kit, reverse transcribed, and concentrated using Quibit ssDNA kit. Quantitative PCR was run on a QuantStudio3 using Power SYBR Green chemistry to confirm the presence of mPC1 in skeletal muscle. Our results revealed that mPC1 was expressed in skeletal muscle along with other genes associated with the mLOC. Immunoblots of mitochondrial lysates contained MCT1, mPC1, LDH, and COX4 in both the skeletal muscle and liver mitochondrial fractions. As expected, MCT1 was also present in RBC lysates as the MCTs are present in both the sarcolemma and mitochondrial membrane. Moreover, LCMS/MS analysis confirmed the presence of mPC1 corroborating our immunoblots. Colocalization using immunocytochemistry confirms the revised mLOC structure. Accordingly, both the pyruvate and lactate transporters assist in maintaining the redox balance and varying rates of carbohydrate oxidation during changing physiological conditions. This promising data has implications for a variety of fields ranging from cancer biology to exercise physiology. NIH Grant #1 R01 AG059715-01 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Two simple assays for assessing the seeding activity of proteopathic tau.

The regional distribution of neurofibrillary tangles of hyperphosphorylated tau aggregates is associated with the progression of Alzheimer's disease (AD). Misfolded proteopathic tau recruits naïve tau and templates its misfolding and aggregation in a prion-like fashion, which is believed to be the molecular basis of propagation of tau pathology. A practical way to assess tau seeding activity is to measure its ability to recruit/bind other tau molecules and to induce tau aggregation. Based on the properties of proteopathic tau, here we report the development of two simple assays to assess tau seeding activity ----- capture assay in vitro and seeded-tau aggregation assay in cultured cells. In the capture assay, proteopathic tau was applied onto a nitrocellulose membrane and the membrane was incubated with cell lysate containing HA-tagged tau151-391 (HA-tau151-391). The captured tau on the membrane was determined by immuno-blots developed with anti-HA. For the seeded-tau aggregation assay, HEK-293FT cells transiently expressing HA-tau151-391 were treated with proteopathic tau in the presence of Lipofectamine 2000 and then lysed with RIPA buffer. RIPA-insoluble fraction containing aggregated tau was obtained by ultracentrifugation and analyzed by immuno-blot developed with anti-HA. To validate these two assays, we assessed the seeding activity of tau in the middle frontal gyrus, middle temporal gyrus and basal forebrain of AD and control brains and found that AD, but not control, brain extracts effectively captured and seeded tau151-391 aggregation. Basal forebrain contained less phospho-tau and tau seeding activity. The levels of captured tau or seeded-tau aggregates were positively correlated to the levels of phospho-tau, Braak stages and tangle sores. These two assays are specific and sensitive and can be carried out in a regular biomedical laboratory setting by using routine biochemical techniques.

Abstract 4757: Loss of KDM5A supports KRAS-driven pancreatic cancer

Abstract Objective: Mutant KRAS is a primary driver of pancreatic ductal adenocarcinoma (PDAC), which exhibits marked hypoxia. Despite the strong association of hypoxia and PDAC, the relationship between KRAS and hypoxia is still poorly understood. The oxygen-sensitive histone lysine demethylase, KDM5A, was recently reported to mediate epigenetic responses to hypoxia independent of the hypoxia-inducible factors. KDM5A epigenetically represses transcription via two mechanisms: by its demethylase activity on activating H3K4me3 marks, and through its interaction with deacetylase complexes containing HDAC1/2, which deacetylates activating H3K9ac and H4K16ac histone marks. Under hypoxic conditions, KDM5A loses its activity, leading to restoration of these H3K4me3 marks, thereby activating KDM5A target genes. The purpose of this study is to understand how KDM5A loss of function contributes to pathogenesis of mutant KRAS-driven pancreatic cancer. Methods: Cell lines derived from mice with pancreas-specific p53 deletion and doxycycline-inducible expression of KrasG12D (iKPC). Protein lysates were prepared using RIPA buffer. Histones were purified by acid extraction. Immunoblotting was used to probe for protein levels of Kdm5a, H3K4me3, H3K9ac, and H4K16ac. Genetic ablation of KrasG12D was performed by culturing iKPCs in tetracycline-free medium. Kras was induced by adding doxycycline to the culture medium. Pharmaceutical inhibition of MEK, proteasome, and Kdm5a were performed by treating iKPCs with mirdametinib, MG-132, and CPI-455, respectively. Knockdown of β-TrCP and FBXW7 were performed by stable expression of shRNA in iKPCs. Protein motif scanning was performed using the Eukaryotic Linear Motif (ELM) Prediction online software. Results: We discovered that Kdm5a protein levels were abrogated by induction of KrasG12D and stabilized by genetic ablation of Kras. Pharmaceutical inhibition of MEK or proteasome function stabilized Kdm5a, indicating that Kras induces Kdm5a proteasomal degradation through the MEK/ERK pathway. H3K4me3, H3K9ac, and H4K16ac histone marks were increased in Kras-on iKPC compared to Kras-off iKPC, consistent the expected effect of Kras-induced Kdm5a degradation. Pharmaceutical inhibition Kdm5a in the Kras-off setting restored H3K4me3, suggesting that Kdm5a contributes to demethylation of H3K4me3 in iKPC. We identified two phosphodegron sites corresponding to β-TrCP and FBXW7 of the ubiquitin ligase complex within the Kdm5a protein sequence. Knockdown of either β-TrCP or FBXW7 in iKPC both stabilized Kdm5a despite induction of Kras. Conclusion: We conclude that Kdm5a plays a tumor suppressor role in pancreatic cancer by epigenetically repressing transcriptional programs necessary for KRAS-driven oncogenesis. Citation Format: Jasper R. Chen, Jincheng Han, Cullen M. Taniguchi, Ronald A. DePinho. Loss of KDM5A supports KRAS-driven pancreatic cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4757.

MP27-05 ANDROGEN RECEPTOR SIGNALING IN THE HUMAN PENIS IS SIMILAR REGARDLESS OF SERUM TESTOSTERONE LEVEL

You have accessJournal of UrologyCME1 Apr 2023MP27-05 ANDROGEN RECEPTOR SIGNALING IN THE HUMAN PENIS IS SIMILAR REGARDLESS OF SERUM TESTOSTERONE LEVEL Katherine Campbell, Alexandra Dullea, Braian Ledesma, Kajal Khodamoradi, Himanshu Arora, and Ranjith Ramasamy Katherine CampbellKatherine Campbell More articles by this author , Alexandra DulleaAlexandra Dullea More articles by this author , Braian LedesmaBraian Ledesma More articles by this author , Kajal KhodamoradiKajal Khodamoradi More articles by this author , Himanshu AroraHimanshu Arora More articles by this author , and Ranjith RamasamyRanjith Ramasamy More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003255.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Testosterone (T) plays an important role in the proper development and maintenance of male reproductive tissues. The normal serum testosterone levels can vary between 300 to 1000 ng/dL. However, it is unclear whether androgen receptor (AR) signaling varies based on serum T levels. The aim of this study was to assess the impact of varied serum testosterone levels on AR signaling in Human Corpus Cavernosum tissue. Based on our previous work on the Androgen Saturation hypothesis, we hypothesized that above 200 ng/dL, AR signaling would not vary. METHODS: We obtained corpus spongiosum biopsies from men undergoing inflatable penile prosthesis placement for high grade erectile dysfunction. After mechanical dispersion of tissue with a homogenizer, the total protein was extracted using RIPA buffer. Quantitative detection of VEGF (Vascular endothelial growth factor), an androgen receptor marker, and AR (Androgen Receptor) expression was evaluated by western blot. The density of the bands in all the blots was quantified using densitometry analysis with ImageJ software. RESULTS: The median age of participants was 60.7 (57.6, 65.9) years. The median serum testosterone level was 378 (257, 419) ng/dl. The western blot results (Figure 1) showed no association in the expression level of VEGF or AR regardless of the serum testosterone level. CONCLUSIONS: Even with a wide range of serum testosterone levels (209-1478 ng/dl), androgen receptor signaling was similar in penile tissue. The results of this study support our previous work to demonstrate that AR signaling may be similar regardless of T level above 200 ng/dL. This suggests that serum testosterone levels might not reflect downstream androgen receptor signaling within the penile tissue. Understanding the AR saturation hypothesis provides important context necessary for appropriate prescribing of exogenous testosterone replacement therapy to optimize patient outcomes. Markers of androgen receptor signaling in tissue could be similar regardless of serum testosterone levels. Therefore, the utility of only serum testosterone levels in considering the effect of testosterone therapy needs to be re-evaluated. Source of Funding: This work was supported by: NIH Grant R01 DK130991 and Clinician Scientist Development Grant from the ACS to Ranjith Ramasamy, SMSNA Sexual Medicine Grant to Kajal Khodamoradi © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e363 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Katherine Campbell More articles by this author Alexandra Dullea More articles by this author Braian Ledesma More articles by this author Kajal Khodamoradi More articles by this author Himanshu Arora More articles by this author Ranjith Ramasamy More articles by this author Expand All Advertisement PDF downloadLoading ...

Measurement of trace elements in murine liver tissue samples: Comparison between ICP-MS/MS and TXRF

BackgroundTrace elements exhibit essential functions in many physiological processes. Thus, for research focusing on trace element homeostasis and metabolism analytical methods allowing for multi-element analyses are fundamental. Small sample amounts may be a big challenge in trace element analyses especially if also other end points want to be addressed in the same sample. Therefore, the aim of the present study was to examine trace elements (iron, copper, zinc, and selenium) in murine liver tissue prepared by a RIPA buffer-based lyses method. Methods and resultsAfter centrifugation, lysates and pellets were obtained and trace elements were analyzed with TXRF in liver lysates. The results were compared to that obtained by a standard microwave-assisted acidic digestion with subsequent ICP-MS/MS analysis of the same liver tissue, liver lysates, and remaining pellets. In addition, trace element concentrations, determined in murine serum with both methods, were compared. For serum samples, both TXRF and ICP-MS/MS provide similar and highly correlating results. Furthermore, in liver lysate samples prepared with RIPA buffer, comparable trace element concentrations were measured by TXRF as with the standard digestion technique and ICP-MS/MS. Only marginal amounts of trace elements were detected in the pellets. ConclusionTaken together, the results obtained by the present study indicate that the RIPA buffer-based method is suitable for sample preparation for trace element analyses via TXRF, at least for the here investigated murine liver samples.

P083 JAK/STAT pathway and IL-6 activity in moderate to severe Ulcerative Colitis

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease with a high social and health care system burden. Despite recent advances in UC treatment with available drugs acting in different signalling pathways related to the disease, there is still a significant proportion of non-responders who end up being overtreated and exposed to treatment's secondary effects. Therefore, it would be helpful to know the activity of each inflammatory pathway involved in UC pathogenesis in order to tailor the best treatment for each patient. The aim of our study was to measure the activation of JAK/STAT pathway and IL-6 levels in colonic biopsies from patients with UC. Methods A prospective, observational single-centre study was designed and it is currently on going. Adult UC patients with any endoscopic activity (Mayo Endoscopic Score (MES) > 0) in a routine colonoscopy were included. Biopsies from inflamed (endoscopically active) and non-inflamed (endoscopically inactive) colon of each patient were homogenised and processed by using RIPA buffer and ultrasounds to obtain cell lysates. Determination of the activation of JAK/STAT pathway was performed by detecting phosphorylated forms of JAK1, JAK2, JAK3, TYK2, STAT1, STAT3 and STAT4 by Western blot. Human Luminex discovery assay was used for IL-6 quantification. Data are shown as percentage, median, interquartile range (IQR) and mean ± standard deviation as appropriate. Results So far, 19 patients were consecutively included (median age 60.9 years (IQR 40.8-66.6), 58% female). About 47% had left-sided UC, 32% extensive UC and 21% had proctitis. Regarding endoscopic activity, 52.6% of patients showed MES-3, 42.1% MES-2 and 5.2% MES-1. IL-6 was increased in biopsies from inflamed colon, while no IL-6 was found in biopsies from non-inflamed colon (p=0.00). Median IL-6 in inflamed colonic biopsies from patients with MES-2 was 41.5pg/ml (IQR 7.4-106.7) and 51.9pg/ml (IQR 17.5-220.5) in patients with MES-3 (p=0.4) (Figure 1). Every patient showed, at least, one phosphorylated JAK protein and one phosphorylated STAT protein from JAK/STAT pathway in inflamed colonic biopsies. Nevertheless, the pattern of activation of JAK/STAT pathway was different in all patients as shown in Figure 2. Conclusion Different activated forms of JAK and STAT kinases are detected in inflamed colonic biopsies from UC patients, even though the activation pattern of JAK/STAT pathway differs among them. IL-6 levels are increased in inflamed colonic biopsies from UC patients while it is not detected in non-inflamed mucosa.

Investigating the Role of Sterol Regulatory-Element Binding Proteins (SREBPs) in Age-Related Macular Degeneration

Background/Objective: SREBPs are transcription factors involved in lipid biogenesis and are known to play a role in angiogenesis. Vascular endothelial growth factor (VEGF) also promotes angiogenesis, with VEGF inhibitors as the predominant treatment for Age-related macular degeneration (AMD). AMD is the leading cause of permanent vision loss in the elderly population and is characterized by choroidal neovascularization (CNV). We hypothesize that VEGF can activate SREBPs in a SCAP-dependent manner. Methods: Human retinal microvascular endothelial cells (HRECs) were grown in 5% media and treated at passage 7. Prior to treatment, cells were all starved for 1h in 0.5% media. To estimate the changes in SREBP activation - HRECs were treated with 50ng/ml VEGF for 1, 4, and 12h or with 20 μM fatostatin, an inhibitor of SREBP activation, translocation into the nucleus, and SREBP transcription for 6h and 12h. Post treatment cells were lysed and protein was collected in RIPA buffer and semi-quantitative changes in target proteins were analyzed using immunoblotting. Statistical analysis was done by t-test, with significance if p<0.05, and sample size of n=2-3. Results: HRECs treated with VEGF exhibited an increasing trend for SREBP-1 and SREBP-2 in the cytoplasmic and nuclear forms at all time points. SCAP did not show a clear trend. HRECs treated with fatostatin exhibited a decreasing trend for SREBP-1 and SREBP-2 in the cytoplasmic form and nuclear SREBP-1 form at both time points. The nuclear form of SREBP-2 increased at both time points. Conclusion and Potential Impact: VEGF has demonstrated a role in SREBP activation, with both playing a role in angiogenesis. Fatostatin inhibition of SREBP indicated a potential antiangiogenic property. The downregulation of SREBP could provide a novel target in controlling and preventing angiogenesis in AMD. Further studies using animal models should elucidate the role of SCAP in VEGF activation of SREBPs.

Cadmium induces apoptosis of mouse spermatocytes (GC-2 spd) by promoting mitochondrial fission

Objective: To study the underlying mechanism of cadmium-induced apoptosis of mouse spermatocytes (GC-2 spd) . Methods: In March 2021, GC-2 spd cells were exposed to different concentrations of CdCl(2) for 24 hours, namely 5 μmol/L CdCl(2) (low-dose) group and 10 μmol/L CdCl(2) (high-dose) group, and unexposed GC-2 spd cells were used as control group. Mitochondrial morphology was observed in the cells stained with Mito-Track Red CMXRos fluorescent probes by confocal microscopy and the mitochrondrial membrane potential was measured by flow cytometry with JC-1 fluorescent probes. Mitochrondrial proteins, cytosolic proteins and total cellular proteins of GC-2 spd cells were extracted using cell mitochondria isolation kit and RIPA buffer, respectively. The expression of mitochondrial homeostasis regulatory proteins (FIS1 and OPA1), and apoptosis-related proteins (Cytochrome c and cleaved Caspase-3) were examined by Western blot. Results: Compared with the cells in the control group, the relative ratio of JC-1 red/green fluorescence signal in the cells of the low-dose and high-dose CdCl(2) groups decreased significantly (0.740±0.071, 0.570±0.028), with a statistically significant difference (P=0.017, 0.004) ; The morphology of mitochondria changed from long tube to point, and the proportion of cells containing point mitochondria increased significantly (45.1%±3.7% and 25.7%±4.9%), the difference was statistically significant (P=0.005, 0.001) ; The relative expression level of mitochondrial FIS1 in cells of low and high dose CdCl(2) groups was significantly higher (1.271±0.120, 1.693±0.155), the difference was statistically significant (P=0.046, 0.000) ; The relative expression level of OPA1 decreased significantly (0.838±0.050, 0.682±0.040), and the difference was statistically significant (P=0.049, 0.001). Compared with the control group, the relative expression level of cytochrome c protein in the cytoplasm of cells in the low dose group of CdCl(2) was not significantly increased (1.249±0.151), and the difference was not statistically significant (P=0.075). However, the relative expression level in the cytoplasm of cells in the high dose group of CdCl(2) was significantly increased (2.355±0.110), and the difference was statistically significant (P=0.000) ; The relative expression level of Cytochrome c in mitochondria of low and high dose CdCl(2) groups decreased significantly (0.681±0.043, 0.619±0.114), with a statistically significant difference (P=0.004, 0.001) ; Moreover, the level of cleaved Caspase-3 protein in cells gradually increased (5.486±0.544, 11.493±1.739), the difference was statistically significant (P=0.004, 0.000) . Conclusion: Cadmium induced cleaved Caspase-3 mediated apoptosis of GC-2 spd cells via promoting mitochrondrial fission and the release of Cytochrome c from the mitochrondria to the cytosol.

Analysis of the Platelet Proteome Reveals Insights into the Pro-Inflammatory and Pro-Thrombotic State Associated with the Philadelphia Chromosome-Negative Myeloproliferative Neoplasms

Introduction: Hypercoagulability, thrombosis and microvascular dysfunction are hallmarks of the Philadelphia chromosome-negative myeloproliferative neoplasms (MPN). Elevated peripheral blood cell counts appear to contribute to thrombotic risk but the precise underlying mechanisms remain to be fully elucidated. The interplay between haemostatic and pro-inflammatory pathway activity ('thrombo-inflammation') has emerged in recent years as a source of hypercoagulability in MPN. Platelets are recognised as being mediators of thrombo-inflammation in other diseases and may also be effectors of pro-inflammatory/pro-coagulant activity in MPN. We hypothesized that the platelet proteome is altered in MPN and that its characterisation would reveal insights into the pathophysiology of the disease and the associated thrombotic risk. Aim: To determine if differences exist in the pattern of platelet protein expression in patients with polycythaemia vera (PV) and essential thrombocythaemia (ET) in contrast to healthy donors. Methods: 62 patients (ET, n=38; PV, n=24) and 9 healthy volunteers were recruited at Papa Giovanni XXIII Hospital, Bergamo, Italy and the Mater Misericordiae University hospital, Dublin, Ireland. Platelets were isolated from platelet rich plasma, washed in Krebs Ringer buffer and resuspended at 1x 109 platelets/mL in phosphate buffered saline. Whole platelets were lysed in RIPA buffer and differential proteomic signatures established using label-free quantification (LFQ) mass spectrometry (MS), where platelet lysate proteins were double digested using the commercially available PreOmics kit and analysed in a Bruker TimsTOF mass spectrometer connected to a EvoSep liquid chromatography system. Identified peptides were searched against a human FASTA using MaxQuant. For statistical analysis, proteins identified in a minimum of 70% of samples in at least one group were included. Differences in protein expression were determined using an unpaired t-test with a false discovery rate of 5% and a minimal fold change of 0.1 within the Perseus software; p- values below 0.05 were considered significant. Results: 2,180 proteins from platelet lysates were quantified across all patient and control samples. In MPN platelet lysates, 49 proteins were found to be differentially expressed in comparison to controls (p< 0.05) (Figure 1), including increased expression of markers of platelet activity such as vesicle-associated membrane protein 7 (VAMP-7; regulator of granule exocytosis and actin cytoskeleton activity) and CD109 (a GPI-linked glycoprotein expressed by activated platelets). Bioinformatical analysis revealed a cohort of mitochondrial, cytoskeletal & ribosomal proteins as well as potential effectors of thrombopoiesis and thrombo-inflammation which were significantly upregulated in the MPN cohort. Strikingly, protein disulfide-isomerase (PDI, a member of the thioredoxin superfamily of redox proteins) was increased in MPN lysates. PDI has been shown to contribute to thrombosis, platelet activation and platelet-neutrophil interactions in vivo; plasma levels of PDI have been shown to be increased in MPN and are associated with thrombosis risk. Conclusion: The platelet proteome is altered in MPN and is suggestive of an activated platelet phenotype with over-expression of proteins with known pro-coagulant activity. To our knowledge the over expression of PDI in MPN platelets has not previously been described. The identification of differentially expressed proteins, such as PDI, provides mechanistic insights into the pathophysiology underlying the substantial burden of arterial and venous thrombosis in MPN and may also assist in the identification of novel therapeutic targets. Additional proteomic analysis of platelet releasate and plasma extracellular vesicles is currently ongoing and may provide additional pathophysiological insights. Figure 1: Volcano plot of MPN versus control platelet lysate proteomes (x-axis, t-test difference between the mean log2 of the LFQ values; y-axis, the negative log transformed p-value) representing the proteins significantly altered in MPN. Black hyperbolic curves show the threshold for statistical significance. 36 proteins were found to be increased in MPN platelet lysates (including CD109, PDIA4 and VAMP-7) in comparison to control lysates (red) while 13 proteins were decreased in MPN platelet lysates (blue). Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Mesowestern Blot: Simultaneous Analysis of Hundreds of Submicroliter Lysates.

Western blotting is a widely used technique for molecular-weight-resolved analysis of proteins and their posttranslational modifications, but high-throughput implementations of the standard slab gel arrangement are scarce. The previously developed Microwestern requires a piezoelectric pipetting instrument, which is not available for many labs. Here, we report the Mesowestern blot, which uses a 3D-printable gel casting mold to enable high-throughput Western blotting without piezoelectric pipetting and is compatible with the standard sample preparation and small (∼1 μL) sample sizes. The main tradeoffs are reduced molecular weight resolution and higher sample-to-sample CV, making it suitable for qualitative screening applications. The casted polyacrylamide gel contains 336, ∼0.5 μL micropipette-loadable sample wells arranged within a standard microplate footprint. Polyacrylamide % can be altered to change molecular weight resolution profiles. Proof-of-concept experiments using both infrared-fluorescent molecular weight protein ladder and cell lysate (RIPA buffer) demonstrate that the protein loaded in Mesowestern gels is amenable to the standard Western blotting steps. The main difference between Mesowestern and traditional Western is that semidry horizontal instead of immersed vertical gel electrophoresis is used. The linear range of detection is at least 32-fold, and at least ∼500 attomols of β-actin can be detected (∼29 ng of total protein from mammalian cell lysates: ∼100–300 cells). Because the gel mold is 3D-printable, users with access to additive manufacturing cores have significant design freedom for custom layouts. We expect that the technique could be easily adopted by any typical cell and molecular biology laboratory already performing Western blots.

Ligand-Dissociation-Type N,N-Dimethylaminopyrene Probes for In-Situ Site-Specific Protein Labeling.

To develop practical methods for in-situ labeling of target proteins and to analyze their binding modes with bioactive ligands, 6-N,N-dimethylaminopyrene-N-acyl-N-alkylsulfonamide-4,8-diazacyclononyne (dmpy-NASA-DACN) tags were synthesized. Strain-promoted azide-alkyne cyclization with azide-conjugated ligands (biotin and sulfonamide) gave ligand-dissociation-type dmpy probes. With these probes, specific labeling of avidin and human carboxylase 1 (hCA1) proceeded even in the presence of cell lysate proteins in ca. 10% RIPA buffer. Affinity purification, in-gel tryptic digestion on polystyrene gel, and MALDI MS analysis established the dmpy-labeled positions of target proteins. Molecular modeling studies also supported why the dmpy-labeling reactions proceeded site-specifically near ligand-binding sites on the target proteins. Our findings might contribute to the development of chemical probes that specifically label various biomacromolecules in cells.

A Novel Anticancer Effect of Ephedra alata Decne in Breast Cancer Cells

Cancer is a class of diseases characterized by uncontrolled cell growth. One of the main aims of developing new therapies is to use natural resources to induce apoptosis. LC-ms/ms analysis of a methanolic extract of Ephedra alata (E.A.) allowed the identification of 20 secondary metabolites, including flavonoids, phenolic acids, and proanthocyanidins. Antiproliferative effect was assessed by crystal violet assay. Antimigration effect was tested by wound healing assay and apoptosis induction was determined by annexin binding assays, Hoechst staining, ROS production, and activation of apoptotic proteins. The results indicated that exposure of breast cancer cells to E.A. extract significantly reduced cell viability in a dose and time-dependent manner and inhibited the migration of 4T1 cells at a low dose. Moreover, treatment of cells with E.A. extract induced apoptosis, as it was detected by Annexin V/7 AAD, Hoechst staining, ROS production, and the activation of caspases. Abbreviation: BSA bovine serum albumin DMSO dimethyl sulfoxide EDTA ethylenediaminetetraacetic acid LC-ms/ms liquid chromatography-mass spectrometry NAC N-acetyl-l-cysteine PARP poly(ADP-ribose) polymerase PMSF phenylmethylsulfonyl fluoride RIPA radioimmunoprecipitation assay buffer ROS reactive oxygen species RPMI Roswell park memorial institute SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

MP38-18 ANDROGEN RECEPTOR SIGNALING IN CORPUS CAVERNOSUM IS SIMILAR IN MEN WITH SERUM TESTOSTERONE LEVELS ABOVE 200 ng/dL

You have accessJournal of UrologyCME1 May 2022MP38-18 ANDROGEN RECEPTOR SIGNALING IN CORPUS CAVERNOSUM IS SIMILAR IN MEN WITH SERUM TESTOSTERONE LEVELS ABOVE 200 ng/dL Kajal Khodamoradi, Alexandra Dullea, Roei Golan, Jesse Ory, Himanshu Arora, and Ranjith Ramasamy Kajal KhodamoradiKajal Khodamoradi More articles by this author , Alexandra DulleaAlexandra Dullea More articles by this author , Roei GolanRoei Golan More articles by this author , Jesse OryJesse Ory More articles by this author , Himanshu AroraHimanshu Arora More articles by this author , and Ranjith RamasamyRanjith Ramasamy More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002592.18AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Testosterone (T) plays an important role in the proper development and maintenance of male reproductive tissues. The normal serum testosterone levels can vary between 300 to 1000 ng/dL. However, it is unclear whether androgen receptor signaling can vary based on serum T levels. What remains unknown is also whether there is a uniform serum T level above which androgen receptor signaling within the tissue remains similar (saturation hypothesis). Therefore, we evaluated whether varying serum levels of T alters androgen receptor (AR) signaling in human penile tissue. METHODS: We obtained human corpus cavernosum (CC) tissue biopsies during penile surgery (either for erectile dysfunction or Peyronie’s disease). We recorded their serum T levels one week prior to surgery. After mechanical dispersion of CC tissue with a homogenizer, the total protein was extracted using RIPA buffer, and quantitative detection of vascular endothelial growth factor (VEGF) was evaluated by western blot. RESULTS: The mean age of participants was 64±10 and the mean T level was 487.46ng/dL±377.20. The results of western blot showed that all corpus cavernosum samples in men with T >200ng/dL expressed similar levels of VEGF in men. However, men with a low serum T level (<200 ng/dL) had decreased expression of VEGF. The VEGF expression from men undergoing penile surgery for Peyronie's disease without erectile dysfunction was used as controls. CONCLUSIONS: Despite a wide range of serum T levels (200-1594 ng/dl), androgen receptor signaling was similar in penile tissue. This data suggests that the saturation value for penile androgen receptors appears to be around approximately 200ng/dL. Understanding androgen receptor saturation hypothesis provides important context necessary for appropriate prescribing of exogenous T to optimize patient outcomes. Source of Funding: This work was supported by Acerus Pharmaceuticals, National Institutes of Health Grant R01 DK130991 and Clinician Scientist Development Grant from the American Cancer Society to RR © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e625 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Kajal Khodamoradi More articles by this author Alexandra Dullea More articles by this author Roei Golan More articles by this author Jesse Ory More articles by this author Himanshu Arora More articles by this author Ranjith Ramasamy More articles by this author Expand All Advertisement PDF DownloadLoading ...