This work was supported by research grants from the National Nature Science Foundation of China (81671006, 81300894), CAMS Innovation Fund for Medical Sciences (2019-I2M-5-038), National clinical key discipline construction project (PKUSSNKP-202102), Innovation Fund for Outstanding Doctoral Candidates of Peking University Health Science Center (BMU2022BSS001).

This study was approved by the institutional review board of Peking University School and Hospital. Informed consent was obtained from the patients. The tissue samples used in this study were deidentified. The study scheme is shown in Figure 1.
1. Sample preparation
<ol>
	<li>Cut formalin-fixed paraffin-embedded oral submucous fibrosis tissues into continuous sections of 3 &#181;m and 10 &#181;m thickness on a microtome.</li>
	<li>Unfold the sections in water and then fish out onto the slides. Fix the 3 &#181;M and 10 &#181;m sections on adhesion microscope slides (slide A) and PEN-membrane slides (slide B), respectively.</li>
	<li>Place the slides on a hot plate at 60 &#176;C for 2 h.</li>
</ol>
2. Hematoxylin-eosin staining
<ol>
	<li>Place slides A and B in xylene (CAUTION) for 10 min and repeat this step thrice.</li>
	<li>Hydrate slides A and B in graded ethanol solutions in the order of 100%, 100%, 90%, 80%, and 70% for 1 min in each concentration.</li>
	<li>Place slides A and B in ultrapure distilled water for 30 s</li>
	<li>Place slides A and B in Harris hematoxylin dye solution for 90 s.</li>
	<li>Place slides A and B in ultrapure distilled water for 30 s and repeat this step thrice.</li>
	<li>Place slides A and B in div-hematoxylin solution (CAUTION) for 2 s.</li>
	<li>Place slides A and B in ultrapure distilled water for 30 s and repeat this step thrice.</li>
	<li>Place slides in A and B in 1% re-blue solution for 2 s.</li>
	<li>Place slides A and B in ultrapure distilled water for 30 s and repeat this step thrice.</li>
	<li>Place slides in eosin solution for 2 s.</li>
	<li>Place slides A and B in ultrapure distilled water for 30 s and repeat this step thrice.</li>
	<li>Dehydrate the slides in graded ethanol solutions in the order of 70%, 80%, 90%, 100%, and 100% for 2 s in each concentration.</li>
	<li>Place slide A in xylene for 3 min and repeat this step twice.</li>
	<li>Add a drop of mounting medium (CAUTION) to slide A and cover it with a cover glass.</li>
</ol>
3. Observation of histological morphology and laser capture microdissection
<ol>
	<li>Initiate the laser microdissection system and software (Figure 2).</li>
	<li>Place slide A on the slide stage and observe the histological morphology to identify the area of interest for laser microdissection.</li>
	<li>Remove slide A and place slide B inversely on the slide stage.</li>
	<li>Click the Unload button (Figure 2) to push out the collection device. Insert a polymerase chain reaction (PCR) tube into the collection device and ensure that the tube is held fixed. Click the OK button (Figure 3).</li>
	<li>Select a cap by clicking the corresponding red circle marking the Collector Device: Tube Caps. The selected circle will turn green.</li>
	<li>Click the Draw button and Draw + Cut button and use the mouse to sketch the area of interest.</li>
	<li>Click the Start Cut button to capture the area of interest; the captured sample will be collected by the cap (Figure 4).</li>
	<li>Click the Lower button to ensure that the captured sample is collected (Figure 5).</li>
	<li>Click the Specimen button to capture the next sample.</li>
	<li>Click the Unload button to unload the PCR tube with the captured sample.</li>
</ol>

Capturing Oral Submucous Fibrosis Tissue Samples for Spatial-Omics Analysis

<ol>
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G., Chatterjee, R., Chaudhuri, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+submucous+fibrosis:+A+global+challenge.+Rising+incidence,+risk+factors,+management,+and+research+priorities.">Oral submucous fibrosis: A global challenge. Rising incidence, risk factors, management, and research priorities.</a> Periodontology 2000. 80 (1), 200-212 (2019).</li><li>Shih, Y. H., Wang, T. H., Shieh, T. M., Tseng, Y. 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The authors declare no conflict of interest.

This protocol reported a pipeline to capture OSF tissue samples with morphological and spatial information for further spatial-omic analyses through laser microdissection. From the representative results, we identified different CNA patterns among various morphology-related samples.
OSF, a type of OPMD, is a common precancerous condition of oral squamous cell carcinoma6. Genomic instability has been reported to be associated with the development and malignant transforma...

Oral submucous fibrosis (OSF) is a chronic, insidious disease that develops mainly in the buccal mucosa and results in restricted mouth opening1. While OSF is a multifactorial disease, areca nut or betel nut chewing is the main cause of OSF2,3. Because of this geographically specific habit, OSF is predominantly concentrated in populations in Southeast and South Asia3. The common histological features of OSF include abnormal collagen deposition in the connective tissue beneath the oral mucosal epithelium, vascular stenosis, and occlusion1. OSF epithelial tissue can present with manifestations of atrophy or hyperplasia and even dysplasia when concomitant with oral leukoplakia4,5.
OSF is defined by the World Health Organization as a common oral potentially malignant disorder (OPMD) that exhibits the potential to progress to oral squamous cell carcinoma with a malignant transformation rate of 4%-6%6,7,8,9. The mechanism underlying the malignant transformation of OSF is complex10. Abnormal growth of the epithelium, including both dysplasia and atrophy, increases the potential for carcinogenesis, and senescent fibroblasts in the stroma may be involved in the malignant progression of OSF by inducing epithelial-mesenchymal transition (EMT) through reactive oxygen species (ROS) and other molecules10.
Technologies for spatial-omic analyses generated multi-omic data with morphological and spatial information that have provided insights into cancer mechanisms11,12,13. Here, we present a protocol to capture morphology-related cell populations from formalin-fixed paraffin-embedded OSF tissue by laser microdissection. Multi-omic analyses of these samples can overcome challenges with intratissue heterogeneity and increase understanding of the molecular pathology and mechanisms of malignant transformation in OSF14.

<table><tbody><tr><td>Adhesion microscope slides</td><td>CITOTEST</td><td>REF.188105</td><td></td></tr><tr><td>Div-haematoxylin</td><td>YiLi</td><td>20230326</td><td></td></tr><tr><td>Eosin solution</td><td>BASO</td><td>BA4098</td><td></td></tr><tr><td>Ethanol</td><td>PEKING REAGENT</td><td>No.32061</td><td></td></tr><tr><td>Harris hematoxylin dye solution</td><td>YiLi</td><td>20230326</td><td></td></tr><tr><td>Hot plate</td><td>LEICA</td><td>HI1220</td><td></td></tr><tr><td>Laser capture microdissection system</td><td>LEICA</td><td>LMD7</td><td>Machine</td></tr><tr><td>Laser microdissection microsystem</td><td>LEICA</td><td>8.2.3.7603</td><td>Software</td></tr><tr><td>Micromount mounting medium</td><td>LEICA</td><td>REF.3801731</td><td></td></tr><tr><td>Microscope cover glass</td><td>CITOTEST</td><td>REF.10212450C</td><td></td></tr><tr><td>Microtome</td><td>LEICA</td><td>RM2235</td><td></td></tr><tr><td>PCR tubes</td><td>AXYGEN</td><td>16421959</td><td></td></tr><tr><td>PEN-membrane slides</td><td>LEICA</td><td>No.11505158</td><td></td></tr><tr><td>Re-blue solution</td><td>YiLi</td><td>20230326</td><td></td></tr><tr><td>Ultrapure distilled water</td><td>Invitrogen</td><td>REF.10977-015</td><td></td></tr><tr><td>Xylene</td><td>PEKING REAGENT</td><td>No.33535</td><td></td></tr></tbody></table>

isolation of cells with morphological and spatial information from oral submucous fibrosis samples by laser capture microdissection

Oral submucous fibrosis (OSF) is a common type of potentially malignant disorder in the oral cavity. The atrophy of epithelium and fibrosis of the lamina propria and the submucosa are often found on histopathological slides. Epithelial dysplasia, epithelial atrophy, and senescent fibroblasts have been proposed to be associated with the malignant transformation of OSF. However, because of the heterogeneity of potentially malignant oral disorders and oral squamous cell carcinoma, it is difficult to identify the specific molecular mechanisms of malignant transformation in OSF. Here, we present a method to obtain a small number of epithelial or mesenchymal cells carrying morphological data and spatial information by laser capture microdissection on formalin-fixed paraffin-embedded tissue slides. Using a microscope, we can precisely capture microscale (~500 cells) dysplastic or atrophic epithelial tissue and fibrotic subepithelial tissue. The extracted cells can be evaluated by genome or transcriptome sequencing to acquire genomic and transcriptomic data with morphological and spatial information. This approach removes the heterogeneity of bulk OSF tissue sequencing and the interference caused by cells in non-lesioned areas, allowing for precise spatial-omics analysis of OSF tissue.

By performing laser microdissection of OSF tissues, we captured samples of dysplastic epithelium, stroma beneath the dysplastic epithelium, atrophic epithelium, and stroma beneath atrophic epithelial tissue (Figure 1).Through extracting DNA and low-depth whole genome sequencing, we were able to analyze morphology-related copy number alterations (CNA)15. CNA is a common form of genomic instability associated with an increased risk of malignant transformation in OPMD<su...

Watch this Scientific Journal Video about Unlocking the Mysteries of Oral Potential Malignancies at JoVE.com

Author Spotlight: Unlocking the Mysteries of Oral Potential Malignancies 

Laser capture microdissection of oral submucous fibrosis tissues allows for precise extraction of cells from histological regions of interest for the analysis of multi-omics data with morphological and spatial information.

Isolation of Cells with Morphological and Spatial Information from Oral Submucous Fibrosis Samples by Laser Capture Microdissection

Oral submucous fibrosis (OSF) is a common type of potentially malignant disorder in the oral cavity. The atrophy of epithelium and fibrosis of the lamina ...

isolation-cells-with-morphological-spatial-information-from-oral

Research

JoVE Journal

Medicine

1.0K Views.  Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices. Onze belangrijkste onderzoeksinteresses zijn de mechanismen van maligne transformatie onder de ontwikkeling van voorspellende modellen van orale, potentieel kwaadaardige aandoeningen zoals orale leukoplakie en orale submuceuze fibrose. Genomische transcriptomische, proteomische en andere multi-omische sequencing-analyse onder deep learning kunstmatige-intelligentiemodellen worden gebruikt om de progressie van orale, mogelijk kwaadaardige aandoeningen naar mondkanker te bestuderen. De huidige ...

Video: Auteur in de schijnwerpers: de mysteries van orale mogelijke maligniteiten ontrafelen 

Laser Capture Microdissection of Mammalian Tissue

Laser capture microscopy, also known as laser microdissection (LMD), enables the user to isolate small numbers of cells or tissues from frozen or formalin-fixed, paraffin-embedded tissue sections. LMD techniques rely on a thermo labile membrane placed either on top of, or underneath, the tissue section. In one method, focused laser energy is used to melt the membrane onto the underlying cells, which can then be lifted out of the tissue section. In the other, the laser energy vaporizes the foil along a path "drawn" on the tissue, allowing the selected cells to fall into a collection device. Each technique allows the selection of cells with a minimum resolution of several microns. DNA, RNA, protein, and lipid samples may be isolated and analyzed from micro-dissected samples. In this video, we demonstrate the use of the Leica AS-LMD laser microdissection instrument in seven segments, including an introduction to the principles of LMD, initializing the instrument for use, general considerations for sample preparation, mounting the specimen and setting up capture tubes, aligning the microscope, adjusting the capture controls, and capturing tissue specimens. Laser-capture micro-dissection enables the investigator to isolate samples of pure cell populations as small as a few cell-equivalents. This allows the analysis of cells of interest that are free of neighboring contaminants, which may confound experimental results.

Laser capture microscopy, also known as laser microdissection (LMD), enables the user to isolate small numbers of cells or tissues from frozen or ...

Biology

A Novel Microdissection Approach to Recovering Mycobacterium tuberculosis Specific Transcripts from Formalin Fixed Paraffin Embedded Lung Granulomas

Microdissection has been used for the examination of tissues at DNA, RNA, and protein levels for over a decade. Laser capture microscopy (LCM) is the most common microdissection technique used today. In this technique, a laser is used to focally melt a thermoplastic membrane that overlies a dehydrated tissue section1. The tissue section composite is then lifted and separated from the membrane. Although this technique can be used successfully for tissue examination, it is time consuming and expensive. Furthermore, the successful completion of procedures using this technique requires the use of a laser, thus limiting its use. A new more affordable and practical microdissection approach called mesodissection is a possible solution to the pitfalls of LCM. This technique employs the MESO-1/MeSectr system to mill the desired tissue from a slide mounted tissue sample while concurrently dispensing and aspirating fluid to recover the desired tissue sample into a consumable mill bit. Before the dissection process begins, the user aligns the formalin fixed paraffin embedded (FFPE) slide with a hematoxylin and eosin stained (H&#38;E) reference slide. Thereafter, the operator annotates the desired dissection area and proceeds to dissect the appropriate segment. The program generates an archived image of the dissection. The main advantage of mesodissection is the short duration needed to dissect a slide, taking an average of ten minutes from set up to sample generation in this experiment. Additionally, the system is significantly more cost effective and user friendly. A slight disadvantage is that it is not as precise as laser capture microscopy. In this article we demonstrate how mesodissection can be used to extract RNA from slides from FFPE granulomas caused by Mycobacterium tuberculosis (Mtb).

A Novel Microdissection Approach to Recovering Mycobacterium tuberculosis Specific Transcripts from Formalin Fixed Paraffin Embedded Lung Granulomas

Microdissection has been extensively employed for the examination of DNA, RNA, and protein within tissue. Laser capture microscopy (LCM) is the most commonly used method, but a new milling technique, mesodissection, is recently available. We demonstrate RNA extraction from mesodissected formalin fixed paraffin embedded tissue slides of Mycobacterium tuberculosis granulomas.

Microdissection has been used for the examination of tissues at DNA, RNA, and protein levels for over a decade. Laser capture microscopy (LCM) is the most ...

Immunology and Infection

Industrialized, Artificial Intelligence-guided Laser Microdissection for Microscaled Proteomic Analysis of the Tumor Microenvironment

The tumor microenvironment (TME) represents a complex ecosystem comprised of dozens of distinct cell types, including tumor, stroma, and immune cell populations. To characterize proteome-level variation and tumor heterogeneity at scale, high-throughput methods are needed to selectively isolate discrete cellular populations in solid tumor malignancies. This protocol describes a high-throughput workflow, enabled by artificial intelligence (AI), that segments images of hematoxylin and eosin (H&#38;E)-stained, thin tissue sections into pathology-confirmed regions of interest for selective harvest of histology-resolved cell populations using laser microdissection (LMD). This strategy includes a novel algorithm enabling the transfer of regions denoting cell populations of interest, annotated using digital image software, directly to laser microscopes, thus enabling more facile collections. Successful implementation of this workflow was performed, demonstrating the utility of this harmonized method to selectively harvest tumor cell populations from the TME for quantitative, multiplexed proteomic analysis by high-resolution mass spectrometry. This strategy fully integrates with routine histopathology review, leveraging digital image analysis to support enrichment of cellular populations of interest and is fully generalizable, enabling harmonized harvests of cell populations from the TME for multiomic analyses.

This protocol describes a high-throughput workflow for artificial intelligence-driven segmentation of pathology-confirmed regions of interest from stained, thin tissue section images for enrichment of histology-resolved cell populations using laser microdissection. This strategy includes a novel algorithm enabling the transfer of demarcations denoting cell populations of interest directly to laser microscopes.

The tumor microenvironment (TME) represents a complex ecosystem comprised of dozens of distinct cell types, including tumor, stroma, and immune cell ...

Cancer Research

Laser Capture Microdissection - A Demonstration of the Isolation of Individual Dopamine Neurons and the Entire Ventral Tegmental Area

Laser capture microdissection (LCM) is used to isolate a concentrated population of individual cells or precise anatomical regions of tissue from tissue sections on a microscope slide. When combined with immunohistochemistry, LCM can be used to isolate individual cells types based on a specific protein marker. Here, the LCM technique is described for collecting a specific population of dopamine neurons directly labeled with&#160;tyrosine hydroxylase immunohistochemistry and for isolation of the dopamine neuron containing region of the ventral tegmental area using indirect tyrosine hydroxylase immunohistochemistry on a section adjacent to those used for LCM. An infrared (IR) capture laser is used to both dissect individual neurons as well as the ventral tegmental area off glass slides and onto an LCM cap for analysis. Complete dehydration of the tissue with 100% ethanol and xylene is critical. The combination of the IR capture laser and the ultraviolet (UV) cutting laser is used to isolate individual dopamine neurons or the ventral tegmental area when using PEN membrane slides. A PEN membrane slide has significant advantages over a glass slide as it offers better consistency in capturing and collecting cells, is faster collecting large pieces of tissue, is less reliant on dehydration and results in complete removal of the tissue from the slide. Although removal of large areas of tissue from a glass slide is feasible, it is considerably more time consuming and frequently leaves some residual tissue behind. Data shown here demonstrate that RNA of sufficient quantity and quality can be obtained using these procedures for quantitative PCR measurements. Although RNA and DNA are the most commonly isolated molecules from tissue and cells collected with LCM, isolation and measurement of microRNA, protein and epigenetic changes in DNA can also benefit from the enhanced anatomical and cellular resolution obtained using LCM.

The isolation of individual dopamine neurons or the ventral tegmental area with direct or indirect immunohistochemistry is demonstrated using laser capture microdissection. Parameters for isolation of tissue from a glass slide using an infrared laser and from membrane slides using the combination of an infrared and ultraviolet laser are discussed.

Laser capture microdissection (LCM) is used to isolate a concentrated population of individual cells or precise anatomical regions of tissue from tissue ...

Neuroscience

Laser-capture Microdissection of Human Prostatic Epithelium for RNA Analysis

The prostate gland contains a heterogeneous milieu of stromal, epithelial, neuroendocrine and immune cell types. Healthy prostate is comprised of fibromuscular stroma surrounding discrete epithelial-lined secretory lumens and a very small population of immune and neuroendocrine cells. In contrast, areas of prostate cancer have increased dysplastic luminal epithelium with greatly reduced or absent stromal population. Given the profound difference between stromal and epithelial cell types, it is imperative to separate the cell types for any type of downstream molecular analysis. Despite this knowledge, the bulk of gene expression studies compare benign prostate to cancer without micro-dissection, leading to stromal bias in the benign samples. Laser-capture micro-dissection (LCM) is an effective method to physically separate different cell types from a specimen section. The goal of this protocol is to show that RNA can be successfully isolated from LCM-collected human prostatic epithelium and used for downstream gene expression studies such as RT-qPCR and RNAseq.

The goal of this protocol is to use laser-capture micro-dissection as an effective method to isolate pure populations of cell types from heterogeneous prostate tissues for downstream RNA analysis.

The prostate gland contains a heterogeneous milieu of stromal, epithelial, neuroendocrine and immune cell types.  Healthy prostate is comprised of ...

Laser Capture Microdissection of Glioma Subregions for Spatial and Molecular Characterization of Intratumoral Heterogeneity, Oncostreams, and Invasion

Gliomas are primary brain tumors characterized by their invasiveness and heterogeneity. Specific histological patterns such as pseudopalisades, microvascular proliferation, mesenchymal transformation and necrosis characterize the histological heterogeneity of high-grade gliomas. Our laboratory has demonstrated that the presence of high densities of mesenchymal cells, named oncostreams, correlate with tumor malignancy. We have developed a unique approach to understand the mechanisms that underlie glioma&#39;s growth and invasion. Here, we describe a comprehensive protocol that utilizes laser capture microdissection (LMD) and RNA sequencing to analyze differential mRNA expression of intra-tumoral heterogeneous multicellular structures (i.e., mesenchymal areas or areas of tumor invasion). This method maintains good tissue histology and RNA integrity. Perfusion, freezing, embedding, sectioning, and staining were optimized to preserve morphology and obtain high-quality laser microdissection samples. The results indicate that perfusion of glioma bearing mice using 30% sucrose provides good morphology and RNA quality. In addition, staining tumor sections with 4% Cresyl violet and 0.5% eosin results in good nuclear and cellular staining, while preserving RNA integrity. The method described is sensitive and highly reproducible and it can be utilized to study tumor morphology in various tumor models. In summary, we describe a complete method to perform LMD that preserves morphology and RNA quality for sequencing to study the molecular features of heterogeneous multicellular structures within solid tumors.

Laser microdissection (LMD) is a sensitive and highly reproducible technique that can be used to uncover pathways that mediate glioma heterogeneity and invasion. Here, we describe an optimized protocol to isolate discrete areas from glioma tissue using laser LMD followed by transcriptomic analysis.

Gliomas are primary brain tumors characterized by their invasiveness and heterogeneity. Specific histological patterns such as pseudopalisades, ...

RNA Isolation from Cell Specific Subpopulations Using Laser-capture Microdissection Combined with Rapid Immunolabeling

Laser capture microdissection (LCM) allows the isolation of specific cells from thin tissue sections with high spatial resolution. Effective LCM requires precise identification of cells subpopulations from a heterogeneous tissue. Identification of cells of interest for LCM is usually based on morphological criteria or on fluorescent protein reporters. The combination of LCM and rapid immunolabeling offers an alternative and efficient means to visualize specific cell types and to isolate them from surrounding tissue. High-quality RNA can then be extracted from a pure cell population and further processed for downstream applications, including RNA-sequencing, microarray or qRT-PCR. This approach has been previously performed and briefly described in few publications. The goal of this article is to illustrate how to perform rapid immunolabeling of a cell population while keeping RNA integrity, and how to isolate these specific cells using LCM. Herein, we illustrated this multi-step procedure by immunolabeling and capturing dopaminergic cells in brain tissue from one-day-old mice. We highlight key critical steps that deserve special consideration. This protocol can be adapted to a variety of tissues and cells of interest. Researchers from different fields will likely benefit from the demonstration of this approach.

Gene expression analysis of a subset of cells in a specific tissue represents a major challenge. This article describes how to isolate high-quality total RNA from a specific cell population by combining a rapid immunolabeling method with laser capture microdissection.

Laser capture microdissection (LCM) allows the isolation of specific cells from thin tissue sections with high spatial resolution. Effective LCM requires ...

Laser-assisted Microdissection (LAM) as a Tool for Transcriptional Profiling of Individual Cell Types

The understanding of developmental processes at the molecular level requires insights into transcriptional regulation, and thus the transcriptome, at the level of individual cell types. While the methods described here are generally applicable to a wide range of species and cell types, our research focuses on plant reproduction. Plant cultivation and seed production is of crucial importance for human and animal nutrition. A detailed understanding of the regulatory networks that govern the formation of the reproductive lineage (germline) and ultimately of seeds is a precondition for the targeted manipulation of plant reproduction. In particular, the engineering of apomixis (asexual reproduction through seeds) into crop plants promises great improvements, as it leads to the formation of clonal seeds that are genetically identical to the mother plant. Consequently, the cell types of the female germline are of major importance for the understanding and engineering of apomixis. However, as the corresponding cells are deeply embedded within the floral tissues, they are very difficult to access for experimental analyses, including cell-type specific transcriptomics. To overcome this limitation, sections of individual cells can be isolated by laser-assisted microdissection (LAM). While LAM in combination with transcriptional profiling allows the identification of genes and pathways active in any cell type with high specificity, establishing a suitable protocol can be challenging. Specifically, the quality of RNA obtained after LAM can be compromised, especially when small, single cells are targeted. To circumvent this problem, we have established a workflow for LAM that reproducibly results in high RNA quality that is well suitable for transcriptomics, as exemplified here by the isolation of cells of the female germline in apomictic Boechera. In this protocol, procedures are described for tissue preparation and LAM, also with regard to RNA extraction and quality control.

Laser-assisted Microdissection LAM as a Tool for Transcriptional Profiling of Individual Cell Types

Here we present a protocol for laser-assisted microdissection of specific plant cell types for transcriptional profiling. While the protocol is suitable for different species and cell types, the focus is on highly inaccessible cells of the female germline important for sexual and apomictic reproduction in the crucifer genus Boechera.

The understanding of developmental processes at the molecular level requires insights into transcriptional regulation, and thus the transcriptome, at the ...

Laser Capture Microdissection on Surgical Tissues to Identify Aberrant Gene Expression in Impaired Wound Healing in Type 2 Diabetes

The global prevalence Type 2 diabetes mellitus (T2DM) is escalating at a rapid rate. Patients with T2DM suffer from a multitude of complications and one of these is impaired wound healing. This can lead to the development of non-healing sores or foot ulcers and ultimately to amputation. In healthy individuals, wound healing follows a controlled and overlapping sequence of events encompassing inflammation, proliferation, and remodelling. In T2DM, one or more of these steps becomes dysfunctional. Current models to study impaired wound healing in T2DM include in vitro scratch wound assays, skin equivalents, or animal models to examine molecular mechanisms underpinning wound healing and/or potential therapeutic options. However, these do not fully recapitulate the complex wound healing process in T2DM patients, and ex vivo human skin tests are problematic due to the ethics of taking punch biopsies from patients where it is known they will heal poorly. Here, a technique is described whereby expression profiles of the specific cells involved in the (dys)functional wound healing response in T2DM patients can be examined using surplus tissue discarded following amputation or elective cosmetic surgery. In this protocol samples of donated skin are collected, wounded, cultured ex vivo in the air liquid interface, fixed at different time points and sectioned. Specific cell types involved in wound healing (e.g., epidermal keratinocytes, dermal fibroblasts (papillary and reticular), the vasculature) are isolated using laser capture microdissection and differences in gene expression analyzed by sequencing or microarray, with genes of interest further validated by qPCR. This protocol can be used to identify inherent differences in gene expression between both poorly healing and intact skin, in patients with or without diabetes, using tissue ordinarily discarded following surgery. It will yield greater understanding of the molecular mechanisms contributing to T2DM chronic wounds and lower limb loss.

This technique provides a guide to inflicting ex vivo wounds, performing laser capture microdissection and quantifying changes in gene expression related to poor wound healing processes in diabetes using clinically relevant human tissue.

The global prevalence Type 2 diabetes mellitus (T2DM) is escalating at a rapid rate. Patients with T2DM suffer from a multitude of complications and one ...

Laser Microdissection: A Technique to Isolate Invading Colorectal Cancer cells from a 3D Organotypic Culture Model

Source: Bullock M. et al., <a href="https://www.jove.com/v/51475"> Molecular Profiling of the Invasive Tumor Microenvironment in a 3-Dimensional Model of Colorectal Cancer Cells and&#160;Ex vivo&#160;Fibroblasts.</a> J. Vis. Exp. (2014).
The video describes the laser dissection of the 3D organotypic co-culture model with micron-level precision. In 3D organotypic models, stromal constituents such as fibroblasts are 3-dimensionally co-cultured with cancer epithelial cells. The 3D model serves as an experimental tool that enables invasion and cancer-stroma interactions to be studied in near-physiological conditions.

Source: Bullock M. et al.,  Molecular Profiling of the Invasive Tumor Microenvironment in a 3-Dimensional Model of Colorectal Cancer Cells and&#160;Ex ...

Isolation of Cells with Morphological and Spatial Information from Oral Submucous Fibrosis Samples by Laser Capture Microdissection

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