ACE2 chromogenic immunostaining protocol optimized for formalin-fixed paraffin-embedded human tissue sections.
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ABSTRACT:
SUBMITTER: Jorgensen M
PROVIDER: S-EPMC8292114 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:We present a new concept, termed tissue lithography (TL), and its implementation which enables retrospective studies on formalin-fixed paraffin-embedded tissue sections. Tissue lithography uses a microfluidic probe to remove microscale areas of the paraffin layer on formalin-fixed paraffin-embedded biopsy samples. Current practices in sample utilization for research and diagnostics require complete deparaffinization of the sample prior to molecular testing. This imposes strong limitations in terms of the number of tests as well as the time when they can be performed on a single sample. Microscale dewaxing lifts these constraints by permitting deprotection of a fraction of a tissue for testing while keeping the remaining of the sample intact for future analysis. After testing, the sample can be sent back to storage instead of being discarded, as is done in standard workflows. We achieve this microscale dewaxing by hydrodynamically confining nanoliter volumes of xylene on top of the sample with a probe head. We demonstrate micrometer-scale, chromogenic and fluorescence-based immunohistochemistry against multiple biomarkers (p53, CD45, HER2 and β-actin) on tonsil and breast tissue sections and microarrays. We achieve stain patterns as small as 100 μm × 50 μm as well as multiplexed immunostaining within a single tissue microarray core with a 20-fold time reduction for local dewaxing as compared to standard protocols. We also demonstrate a 10-fold reduction in the rehydration time, leading to lower processing times between different stains. We further show the potential of TL for retrospective studies by sequentially dewaxing and staining four individual cores within the same tissue microarray over four consecutive days. By combining tissue lithography with the concept of micro-immunohistochemistry, we implement each step of the IHC protocol-dewaxing, rehydration and staining-with the same microfluidic probe head. Tissue lithography brings a new level of versatility and flexibility in sample processing and budgeting in biobanks, which may alleviate current sample limitations for retrospective studies in biomarker discovery and drug screening.
| S-EPMC5426611 | biostudies-literature
Project description:With the advent of new molecular diagnostic techniques, retrieving DNA from the formalin-fixed paraffin-embedded (FFPE) tissues has become an essential yet challenging step for efficient downstream processes. Owing to low quality and quantity of DNA retrieved from the FFPE sections, the process is often impractical and needs significant improvements. Here, we established an efficient method for the purification of DNA from FFPE specimens by optimizing incubation temperature, incubation time, and the concentration of a formalin scavenger tris(hydroxymethyl)aminomethane (Tris) for reverse-crosslinking. The optimized method, named "Highly concentrated Tris-mediated DNA extraction" (HiTE), yielded three times the DNA yield per tissue slice compared with a representative DNA extraction kit. Moreover, the use of HiTE-extracted DNA increased the yield of the sequencing library three times and accordingly yielded a log higher and more reproducible sequencing library compared with that obtained using the commonly used commercial kit. The sequencing library prepared from HiTE-extracted FFPE-DNA had longer inserts and produced reads that evenly covered the reference genome. Successful application of HiTE-extracted FFPE-DNA for whole-genome and targeted gene panel sequencing indicates its practical usability.
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Project description:Pythium insidiosum is an infectious oomycete affecting dogs that develop the cutaneous or gastrointestinal form of pythiosis with a poor prognosis. If left untreated, pythiosis may be fatal. This organism is not a true fungus because its cell wall and cell membrane lack chitin and ergosterol, respectively, requiring specific treatment. Identifying the organism is challenging, as a hematoxylin and eosin (H&E) stain poorly stain the P. insidiosum hyphae and cannot be differentiated conclusively from other fungal or fungal-like organisms (such as Lagenidium sp.) morphologically. Our study aimed to develop a nested PCR to detect P. insidiosum and compare it with the traditional histopathologic detection of hyphae. Formalin-fixed, paraffin-embedded (FFPE) tissue scrolls from 26 dogs with lesions suggesting the P. insidiosum infection were assessed histologically, and DNA was extracted from the FFPE tissue sections for nested PCR. Agreement between the histologic stains, (H&E), periodic acid-Schiff (PAS), and/or Grocott methenamine silver (GMS) and the nested PCR occurred in 18/26 cases. Hyphae consistent with Pythium sp. were identified via histopathology in 57.7% of the samples, whereas the nested PCR detected P. insidiosum in 76.9% of samples, aiding in the sensitivity of the diagnosis of pythiosis in dogs. Using this combination of techniques, we report 20 canine cases of pythiosis over 18 years in Indiana and Kentucky, an unexpectedly high incidence for temperate climatic regions. Using a combination of histopathology evaluation and nested PCR is recommended to aid in the accurate diagnosis of pythiosis.
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Project description:Formalin-fixed paraffin-embedded (FFPE) tissue specimens constitute a highly valuable source of clinical material for retrospective molecular studies. However, metabolomic assessment of such archival material remains still in its infancy. Hence, there is an urgent need for efficient methods enabling extraction and profiling of metabolites present in FFPE tissue specimens. Here we demonstrate the methodology for isolation of primary metabolites from archival tissues; either fresh-frozen, formalin-fixed or formalin-fixed and paraffin-embedded specimens of mouse kidney were analysed and compared in this work. We used gas chromatography followed by mass spectrometry (GC/MS approach) to identify about 80 metabolites (including amino acids, saccharides, carboxylic acids, fatty acids) present in such archive material. Importantly, about 75% of identified compounds were detected in all three types of specimens. Moreover, we observed that fixation with formalin itself (and their duration) did not affect markedly the presence of particular metabolites in tissue-extracted material, yet fixation for 24h could be recommended as a practical standard. Paraffin embedding influenced efficiency of extraction, which resulted in reduced quantities of several compounds. Nevertheless, we proved applicability of FFPE specimens for non-targeted GS/MS-based profiling of tissue metabolome, which is of great importance for feasibility of metabolomics studies using retrospective clinical material.
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Project description:BackgroundArray Comparative Genomic Hybridization (aCGH) is a rapidly evolving technology that still lacks complete standardization. Yet, it is of great importance to obtain robust and reproducible data to enable meaningful multiple hybridization comparisons. Special difficulties arise when aCGH is performed on archival formalin-fixed, paraffin-embedded (FFPE) tissue due to its variable DNA quality. Recently, we have developed an effective DNA quality test that predicts suitability of archival samples for BAC aCGH.MethodsIn this report, we first used DNA from a cancer cell-line (SKBR3) to optimize the aCGH protocol for automated hybridization, and subsequently optimized and validated the procedure for FFPE breast cancer samples. We aimed for highest throughput, accuracy, and reproducibility applicable to FFPE samples, which can also be important in future diagnostic use.ResultsOur protocol of automated array-CGH on archival FFPE ULS-labeled DNA showed very similar results compared with published data and our previous manual hybridization method.ConclusionThis report combines automated aCGH on unamplified archival FFPE DNA using non-enzymatic ULS labeling, and describes an optimized protocol for this combination resulting in improved quality and reproducibility.
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Project description:BackgroundInvestigating the expression of candidate genes in tissue samples usually involves either immunohistochemical labelling of formalin-fixed paraffin-embedded (FFPE) sections or immunofluorescence labelling of cryosections. Although both of these methods provide essential data, both have important limitations as research tools. Consequently, there is a demand in the research community to be able to perform routine, high quality immunofluorescence labelling of FFPE tissues.ResultsWe present here a robust optimised method for high resolution immunofluorescence labelling of FFPE tissues, which involves the combination of antigen retrieval, indirect immunofluorescence and confocal laser scanning microscopy. We demonstrate the utility of this method with examples of immunofluorescence labelling of human kidney, human breast and a tissue microarray of invasive human breast cancers. Finally, we demonstrate that stained slides can be stored in the short term at 4 degrees C or in the longer term at -20 degrees C prior to images being collected. This approach has the potential to unlock a large in vivo database for immunofluorescence investigations and has the major advantages over immunohistochemistry in that it provides higher resolution imaging of antigen localization and the ability to label multiple antigens simultaneously.ConclusionThis method provides a link between the cell biology and pathology communities. For the cell biologist, it will enable them to utilise the vast archive of pathology specimens to advance their in vitro data into in vivo samples, in particular archival material and tissue microarrays. For the pathologist, it will enable them to utilise multiple antibodies on a single section to characterise particular cell populations or to test multiple biomarkers in limited samples and define with greater accuracy cellular heterogeneity in tissue samples.
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Project description:Eosin Y is a common stain in histology. Although usually used for colourimetric imaging where the dye is used to stain pink/red a range of structures in the tissue, Eosin Y is also a fluorochrome, and has been used in this manner for decades. In this study our aim was to investigate the fluorescence properties of the dye to enable quantification of structures within formalin-fixed paraffin-embedded (FFPE) tissue sections. To do this, FFPE sections of hamster tissue were prepared with haematoxylin and eosin Y dyes. Spectral detection on a confocal laser scanning microscope was used to obtain the fluorescence emission spectra of the eosin Y under blue light. This showed clear spectral differences between the red blood cells and congealed blood, compared to the rest of the section. The spectra were so distinct that it was possible to discern these in fluorescence and multi-photon microscopy. An image analysis algorithm was used to quantify the red blood cells. These analyses could have broad applications in histopathology where differentiation is required, such as the analysis of clotting disorders to haemorrhage or damage from infectious disease.
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Project description:miRNA expression analysis was done on Uveal melanoma, metastatic and non - metastatic case in formalin fixed paraffin embedded sections, identified from case registry and confirmed by Chromosome insitu hybridization harboring monosomy 3 aberration in metastaic case and no aberration in non metastatic case. 19 miRNAs were found to be expressed only in class I tumors (choroidal melanoma) and not in class II (liver metastasis) and 11 miRNAs were found to be expressed only in class II and not in class I. The tumors were found to harbor oncomirs in both choroidal melanoma and metastasizing melanoma targeting tumor suppressor genes and metastatic suppressor genes. None of the differentially expressed miRNAs in either case were found to be located on the chromosomes which have been proved to carry chromosomal abnormalities. Rather it was found that genes targeted by the miRNAs were found to be present in chromosomal regions that are often found to be deleted 8p22, 13q and 17p. Organism used: Homo sapiens. * Slides: Human miRNA V2 8x15k Arrays AMADID: 19118. * Starting material: 18 slides with formalin fixed Paraffin embedded sections-20 μm. * RNA Samples used: 225-94-DUP, 225-94-E, 727-07-DUP, 727-07 -E. * Labeling kit: Agilent miRNA labeling reagent and Hybridization Kit. * Labeling Method: Ligation of one cyanine3-pCp molecule to the 3' end of RNA molecule with greater than 90% efficiency that generates fluorescent miRNA. * Total RNA and cRNA Purification Kit: Biorad MicroBio Spin 6 columns. * Hybridization Kit: Agilent miRNA Hybridization kit. Hybridization protocol See Agilent Technologies website for miRNA microarray hybridization and wash protocol: http://www.chem.agilent.com/scripts/LiteraturePDF.asp?iWHID=50500 Scan protocol Laser detection of Cyanine 3 and Cyanine 5 fluorescence is performed using a confocal scanning instrument containing two tuned lasers, which excite Cyanine dyes at the appropriate wavelengths. Description Microarrays were scanned on an Agilent scanner (G2505C) at 100% PMT with 10% for lower intensity (XDR Scanning).Data extraction was carried out with Agilent Feature Extraction software (version 9.1), and normalization was done using linear per array algorithm according to the manufacturer’s protocol Data processing Feature extracted data was analyzed using GeneSpring GX v 10.0.2 software from Agilent. Normalization of the data was done in GeneSpring GX using the recommended Percentile shift normalization (50th percentile) . Further quality control of normalized data was done using correlation based condition tree to eliminate bad experiments. High expressed miRNA's were clustered using gene tree to identify significant gene expression patterns.
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Project description:Aberrant glycosylation is associated with most of the diseases. Direct imaging and profiling of N-glycans on tissue sections can reveal tissue-specific and/or disease-associated N-glycans, which not only could serve as molecular signatures for diagnosis but also shed light on the functional roles of these biomolecules. Mass spectrometry imaging (MSI) is a powerful tool that has been used to correlate peptides, proteins, lipids, and metabolites with their underlying histopathology in tissue sections. Here, we report an MSI technique for direct analysis of N-glycans from formalin-fixed paraffin-embedded (FFPE) tissues. This technique consists of sectioning FFPE tissues, deparaffinization, and rehydration of the sections, denaturing tissue proteins, releasing N-linked glycans from proteins by printing peptide-N-glycosidase F over the sections, spray-coating the tissue with matrix, and analyzing N-glycans by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Brain sections from a C57BL/6 mouse were imaged using this technique at a resolution of 100 ?m. Forty-two N-glycans were analyzed from the mouse brain section. The mass spectrometry images were used to study the relative abundance of oligomannose, nonfucosylated, and fucosylated complex N-glycans in different brain areas including isocortex, hippocampal formation, and brainstem and specific glycans associated with different areas of the brain were identified. Furthermore, glioblastoma tumor xenografts in a NOD/SCID mouse were imaged. Several glycans with differential expression in tumor versus normal brain tissues were identified. The MSI technique allows for imaging of N-glycans directly from FFPE sections. This method can potentially identify tissue-specific and/or disease-associated glycans coexpressed with other molecular signatures or within certain histological structures.
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Project description:We developed a real-time PCR which allowed the highly sensitive detection of Naegleria fowleri in histological brain tissue sections from experimentally infected mice. This genus-specific small-subunit (18S) rRNA gene-based PCR can complement conventional (immuno-) histology for the diagnosis of primary amoebic meningoencephalitis in paraffin-embedded brain necropsy specimens that had been fixed in formalin buffered with phosphate-buffered saline.
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