Authors would like to thank Catherine Solioz for her skillful assistance.

1. BCM Preparation
<ol>
	<li>Obtain pig mandibles from the local butcher as fresh as possible. Place the mandibles onto a firm surface and release a full thickness flap paying special attention not to leave any soft tissue or periosteum attached to the bone. Work in a clean environment without the need to work under the flow hood.</li>
	<li>Once a full thickness flap is released, use a bone scraper to harvest the bone chips from the buccal side. Please note that the bone scraper has to be sharp. Handle firmly the bone scraper and with long movements collect the bone. Discard bone chips smaller that 1mm.
	<ol>
		<li>To maintain native bone chips, place directly the bone chips in plastic dishes of 10cm diameter with Dulbecco&#39;s Modified Eagle&#39;s medium (DMEM) supplemented with 1% antibiotics and antimycotics not letting them to dry out.</li>
		<li>To evaluate the impact of thermal processing, subject bone chips to pasteurization for 30 min at 80 &#176;C or autoclave for 20 min at 121 &#176;C.</li>
		<li>To evaluate the impact of demineralization, shake bone chips in 1 M HCL for 4-6 hr at 4 &#176;C and wash repeatedly with culture medium until the pH is neutral.</li>
	</ol>
	</li>
	<li>Place a total of 5 g of bone chips per 10 ml fresh DMEM supplemented with 1% antibiotics and antimycotics into a new plastic dish.</li>
	<li>Place the plastic dishes in a humidified atmosphere at 37 &#176;C for 24 hr. Then, harvest BCM. Centrifuge the BCM at 200 x g for 10 min to remove debris, filter it sterile (0.2 nm), and keep aliquots frozen at -80 &#176;C.</li>
	<li>Thaw the BCM stock immediately before use and avoid repeated cycles of freezing and thawing.</li>
	<li>For indicated experiments, soak collagen membranes with BCM or serum-free medium for 1 hr at RT. Wash vigorously the membranes with PBS and place them into 96 well plates. Wet membranes are seeded with cells.</li>
	<li>BCM preparation process is summarized in Figure 1.</li>
</ol>
2. Bioassays Based on Mesenchymal Cells
<ol>
	<li>Seed human mesenchymal cells (for example bone cells, gingival and periodontal ligament fibroblasts) into a 12-well plate with a concentration of 30,000 cells/cm2. To seed the cells use growth medium consisting of DMEM, 10% fetal calf serum and antibiotics. Let the cells attach to the plate O/N.</li>
	<li>Discard the culture medium and wash the cells with pre-warmed PBS at 37 &#176;C. Stimulate the cells by adding pre-warmed serum-free culture medium with and without 20% BCM. Place the cells in a humidified atmosphere at 37 &#176;C for 24 hr.</li>
	<li>Discard the culture medium, rinse the cells with pre-warmed PBS and extract the RNA according to your preferred protocol.</li>
	<li>Adjust the concentration of RNA in order to have the same amount of RNA in each sample. Prepare cDNAs and perform a qRT-PCR to analyse the selected genes using the primers shown in Table 1. 
	NOTE: These are the dilutions of every component: 2x SYBR Green, 20x primer forward, 20x primer reverse, 5x sterile DD water, 5x cDNA. The qRT-PCR is performed in 40 cycles of 95 &#176;C 15 sec and 60 &#176;C 1 min.</li>
	<li>Calculate the relative expression levels by normalizing to the housekeeping gene GAPDH using the &#916;(&#916;Ct) method where &#916;CT is CT target - CT GAPDH and &#916;(&#916;CT) is &#916;CT stimulated - &#916;CT control.</li>
	<li>After this quality control, add BCM to culture medium to stimulate all types of cells including mesenchymal cells, hematopoietic cells or endothelial cells.</li>
</ol>

<ol>
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T., Weber, H. P., Belser, U. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+implant+placement+following+single-tooth+extraction+in+the+esthetic+zone:+biologic+rationale+and+surgical+procedures).">Early implant placement following single-tooth extraction in the esthetic zone: biologic rationale and surgical procedures).</a> The International journal of periodontics &amp; restorative dentistry. 28, 441-451 (2008).</li><li>Stoecklin-Wasmer, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Absorbable+collagen+membranes+for+periodontal+regeneration:+a+systematic+review.">Absorbable collagen membranes for periodontal regeneration: a systematic review.</a> Journal of dental research. 92, 773-781 (2013).</li></ol>

The authors have nothing to disclose. Jordi Caball&#233;-Serrano received a scholarship from the Foundation of Dental Research and Education, Basel, Switzerland.

Bone-conditioned medium reflects the released activity of bone grafts during the early stages of bone regeneration. The protocol described here can be adapted to study the response of different types of cells involved in bone regeneration. Furthermore, the protocol can be used to prepare conditioned medium from processed bone or bone fillers. The methods are easy to perform and rely on a simple concept: the factors released from various native and processed bone. Understanding how BCM affects mesenchymal cells can help t...

Autologous bone is widely used to bridge defects that occurred as a consequence of malformation, resective surgery, reconstructive trauma surgery, and prior to implant placement 1,2. Understanding the biological principles of how bone grafts support the process of graft consolidation is not only key to understand why autografts are considered to be the gold standard in reconstructive surgery, it is also bionic to the improved design of bone substitutes 3. Still, graft consolidation is faster with autologous bone compared to bone substitutes 4,5. Thus, it is imperative to reveal the molecular and cellular mechanisms that make autologous bone so effective to support bone regeneration.
There are three textbook characteristics of autografts that are considered to support the consolidation process 6,7. First, autologous bone is osteoconductive, providing guidance for the newly formed bone to grow into the defect. Secondly, autologous bone is osteogenic, meaning that it contains mesenchymal cells that can differentiate into osteoblasts 8. Third, autologous bone is osteoinductive as growth factors like bone morphogenetic proteins entombed in the matrix can initiate the process of endochondral or even intramembranous bone formation 9. There is another aspect: freshly prepared bone chips hold a paracrine function based on the in vitro observations with &#8220;bone-conditioned medium&#8221; 10-15. Also the impact of myelopoiesis should be mentioned 16. A similar term &#8220;demineralized bone matrix-conditioned medium&#8221; was already coined in 1996 and supports the overall concept of a paracrine function of bone, even when processed by demineralization 17. For our purposes, BCM can be prepared from fresh pig mandibles 10,11. Proteomic analyses of BCM revealed the complex composition, including growth factors and constituents of the extracellular matrix 10, also extending existing knowledge on the proteasome of whole bone 18,19. Thus, BCM should reflect the released activity of various modifications of bone grafts in vitro.
What happens when mesenchymal cells, for example those isolated from bone chips or from oral soft tissue, are exposed to BCM? In vitro, BCM reduces osteogenic and adipogenic differentiation, and provokes a strong increase of IL11 expression 11. Genome wide microarray revealed more genes to be differentially expressed in mesenchymal cells in response to BCM. Among these genes are adrenomedullin (ADM), IL11, IL33, NADPH oxidase 4 (NOX4), proteoglycan 4 (PRG4, or lubricin) and pentraxin 3 (PTX3) 15. BCM obtained from autoclaved bone chips failed to change the expression of the respective genes 14. BCM from bone chips that underwent pasteurization and freezing was able to change gene expression 14. Also conditioned medium of demineralized bone matrix (DBM-CM) changes the expression of TGF-&#946;-regulated genes 20. Interestingly, collagen barrier membranes used to shield the bone chips from the surrounding soft tissue 21,22, adsorbed those parts of BCM that are responsible for the changes in gene expression 23. BCM research can be extended to other cell types involved in bone regeneration such as bone-resorbing osteoclasts and endothelial cells, to name a few. Overall, the accumulating in vitro data provide the scientific basis for the design of a preclinical study.
The present protocol is two-fold: First, it shows how to prepare BCM. Secondly, it shows how to test its biological activity based on mesenchymal cells in vitro.

<table><tbody><tr><td>Pig Mandibles</td><td>Local bucher</td><td></td><td></td></tr><tr><td>Bone Scraper</td><td>Hu-Friedy</td><td>PPBUSE2/36</td><td></td></tr><tr><td>Antibiotics &amp;amp; Antimicotics</td><td>All life Technologies</td><td>15240-062</td><td></td></tr><tr><td>Collagen Membranes (Bio-Gide)</td><td>Geistlich</td><td></td><td></td></tr><tr><td>Fetal Calf Serum</td><td>Invitrogen Corporation</td><td>16030074</td><td></td></tr><tr><td>DMEM</td><td>Invitrogen Corporation</td><td>21885-025</td><td></td></tr><tr><td>&lt;br/&gt; High Pure RNA Isolation Kit</td><td>Roche</td><td>11828665001</td><td></td></tr><tr><td>Transcriptor First Strand cDNA Synthesis Kit</td><td>Roche</td><td>4379012001</td><td></td></tr><tr><td>Primers</td><td>Microsynth</td><td></td><td></td></tr><tr><td>SYBR Green (for Q-RT-PCR)</td><td>Roche</td><td>4673484001</td><td></td></tr><tr><td>PBS</td><td>Roche</td><td>11666789001</td><td></td></tr></tbody></table>

bone conditioned medium: preparation and bioassay

Autologous bone grafts are widely used in oral and maxillofacial surgery, orthopedics, and traumatology. Autologous bone grafts not only replace missing bone, they also support the complex process of bone regeneration. This favorable behavior of autografts is attributed to the three characteristics: osteoconductivity, osteogenicity, and osteoinductivity. However, there is another aspect: Bone grafts release a myriad of molecules, including growth factors, which can target mesenchymal cells involved in bone regeneration. The paracrine properties of bone grafts can be studied in vitro by the use of bone-conditioned medium (BCM). Here we present a protocol on how to prepare bone-conditioned medium from native pig cortical bone, and bone that underwent thermal processing or demineralization. Cells can be directly exposed to BCM or seeded onto biomaterials, such as collagen membranes, previously soaked with BCM. We give examples for in vitro bioassays with mesenchymal cells on the expression of TGF-&#946; regulated genes. The presented protocols should encourage to further reveal the paracrine effects of bone grafts during bone regeneration and open a path for translational research in the broad field of reconstructive surgery.

Bone Conditioned Medium is prepared from fresh porcine bone chips. General overview of the process to prepare BCM and to use biomaterials in combination with BCM is shown in Figure 1 and Figure 2 respectively. During the BCM preparation, it is important to obtain large bone chips with long movements as short movements or very small bone chips can affect the quality of the final BCM. Quality of BCM can be controlled by analyzing the gene expression of BCM target genes: ADM, PTX3, IL11, IL...

Watch this Scientific Journal Video about Bone Conditioned Medium: Preparation and Bioassay at JoVE.com

Bone Conditioned Medium: Preparation and Bioassay

We describe here how to prepare bone-conditioned medium (BCM) and test its activity in vitro.

Autologous bone grafts are widely used in oral and maxillofacial surgery, orthopedics, and traumatology. Autologous bone grafts not only replace missing ...

bone-conditioned-medium-preparation-and-bioassay

Research

JoVE Journal

Biology

11.0K Views.  School of Dental Medicine, University of Bern. We describe here how to prepare bone-conditioned medium (BCM) and test its activity in vitro.

Video: Bone Conditioned Medium: Preparation and Bioassay

Toxoplasma gondii Cyst Wall Formation in Activated Bone Marrow-derived Macrophages and Bradyzoite Conditions

Toxoplasma gondii is an obligate intracellular parasite that can invade any nucleated cell of warm-blooded animals. During infection, T. gondii disseminates as a fast replicating form called the tachyzoite. Tachyzoites convert into a slow-growing encysted form called the bradyzoite by a signaling process that is not well characterized. Within animals, bradyzoite cysts are found in the central nervous system and muscle tissue and represent the chronic stage of infection. Conversion to bradyzoites can be simulated in tissue culture by CO2 starvation, using medium with high a pH, or the addition of interferon gamma (IFN&gamma;). Bradyzoites are characterized by the presence of a cyst wall, to which the lectin Dolichos biflorus agglutinin (DBA) binds. Fluorescently labeled DBA is used to visualize the cyst wall in parasites grown in human foreskin fibroblasts (HFFs) that have been exposed to low CO2 and high pH medium. Similarly, parasites residing in murine bone marrow-derived macrophages (BMMs) display a cyst wall detectable by DBA after the BMMs are activated with IFN&gamma; and lipopolysaccharide (LPS). This protocol will demonstrate how to induce conversion of T. gondii to bradyzoites using a high pH growth medium with low CO2 and activation of BMMs. Host cells will be cultured on coverslips, infected with tachyzoites and either activated with addition of IFN&gamma; and LPS (BMMs) or exposed to a high pH growth medium (HFFs) for three days. Upon completion of infections, host cells will be fixed, permeabilized, and blocked. Cyst walls will be visualized using rhodamine DBA with fluorescence microscopy.

Toxoplasma gondii Cyst Wall Formation in Activated Bone Marrow-derived Macrophages and Bradyzoite Conditions

Toxoplasma gondii converts to a cyst form in response to environmental stresses, which can be mimicked in tissue culture models. This video demonstrates techniques to examine cyst wall formation by activating bone marrow-derived macrophages or changing growth medium pH in fibroblast cells.

Toxoplasma gondii is an obligate intracellular parasite that can invade any nucleated cell of warm-blooded animals. During infection, T. gondii ...

Immunology and Infection

Three-Dimensional Bone Extracellular Matrix Model for Osteosarcoma

Osteosarcoma (OS) is the most common and a highly aggressive primary bone tumor. It is characterized with anatomic and histologic variations along with diagnostic or prognostic difficulties. OS comprises genotypically and phenotypically heterogeneous cancer cells. Bone microenvironment elements are proved to account for tumor heterogeneity and disease progression. Bone extracellular matrix (BEM) retains the microstructural matrices and biochemical components of native extracellular matrix. This tissue-specific niche provides a favorable and long-term scaffold for OS cell seeding and proliferation. This article provides a protocol for the preparation of BEM model and its further experimental application. OS cells can grow and differentiate into multiple phenotypes consistent with the histopathological complexity of OS clinical specimens. The model also allows visualization of diverse morphologies and their association with genetic alterations and underlying regulatory mechanisms. As homologous to human OS, this BEM-OS model can be developed and applied to the pathology and clinical research of OS.

The bone extracellular matrix (BEM) model for osteosarcoma (OS) is well established and shown here. It can be used as a suitable scaffold for mimicking primary tumor growth in vitro and providing an ideal model for studying the histologic and cytogenic heterogeneity of OS.

Osteosarcoma (OS) is the most common and a highly aggressive primary bone tumor. It is characterized with anatomic and histologic variations along with ...

Cancer Research

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation

Osteoclasts are unique bone-resorbing cells that differentiate from the monocyte/macrophage lineage of bone marrow. Dysfunction of osteoclasts may result in a series of bone metabolic diseases, including osteoporosis. To develop pharmaceutical targets for the prevention of pathological bone mass loss, the mechanisms by which osteoclasts differentiate from precursors must be understood. The ability to isolate and culture a large number of osteoclasts in vitro is critical in order to determine the role of specific genes in osteoclast differentiation. Inactivation of the mammalian/mechanistic target of rapamycin complex 1 (TORC1) in osteoclasts can decrease osteoclast number and increase bone mass; however, the underlying mechanisms require further study. In the present study, a RANKL-based protocol to isolate and culture osteoclasts from mouse bone marrow and to study the influence of mTORC1 inactivation on osteoclast formation is described. This protocol successfully resulted in a large number of giant osteoclasts, typically within one week. Deletion of Raptor impaired osteoclast formation and decreased the activity of secretory tartrate-resistant acid phosphatase, indicating that mTORC1 is critical for osteoclast formation.

This manuscript describes a protocol to isolate and culture osteoclasts in vitro from mouse bone marrow, and to study the role of the mammalian/mechanistic target of rapamycin complex 1 in osteoclast formation.

Osteoclasts are unique bone-resorbing cells that differentiate from the monocyte/macrophage lineage of bone marrow. Dysfunction of osteoclasts may result ...

Developmental Biology

Biological Compatibility Profile on Biomaterials for Bone Regeneration

Large non-union bone fractures are a significant challenge in orthopedic surgery. Although auto- and allogeneic bone grafts are excellent for healing such lesions, there are potential complications with their use. Thus, material scientists are developing synthetic, biocompatible biomaterials to overcome these problems. In this study, we present a multidisciplinary platform for evaluating biomaterials for bone repair. We combined expertise from bone biology and immunology to develop a platform including in vitro osteoclast (OC) and osteoblast (OB) assays and in vivo mouse models of bone repair, immunogenicity, and allergenicity. We demonstrate how to perform the experiments, summarize the results, and report on biomaterial biocompatibility. In particular, we tested OB viability, differentiation, and mineralization and OC viability and differentiation in the context of &#946;-tricalcium phosphate (&#946;-TCP) disks. We also tested a &#946;-TCP/Collagen (&#946;-TCP/C) foam which is a commercially available material used clinically for bone repair in a critical-sized calvarial bone defect mouse model to determine the effects on the early phase of bone healing. In parallel experiments, we evaluated immune and allergic responses in mice. Our approach generates a biological compatibility profile of a bone biomaterial with a range of parameters necessary for predicting the biocompatibility of biomaterials used for bone healing and repair in patients.

The number of novel biomaterials engineered for repairing large bone lesions is continuously expanding with the aim to enhance bone healing and overcome the complications associated with bone transplantation. Here, we present a multidisciplinary strategy for pre-clinical biocompatibility testing of biomaterials for bone repair.

Large non-union bone fractures are a significant challenge in orthopedic surgery. Although auto- and allogeneic bone grafts are excellent for healing such ...

Bioengineering

Assessment of Antibody-based Drugs Effects on Murine Bone Marrow and Peritoneal Macrophage Activation

Macrophages are phagocytic innate immune cells, which initiate immune responses to pathogens and contribute to healing and tissue restitution. Macrophages are equally important in turning off inflammatory responses. We have shown that macrophages stimulated with intravenous immunoglobulin (IVIg) can produce high amounts of the anti-inflammatory cytokine, interleukin 10 (IL-10), and low levels of pro-inflammatory cytokines in response to bacterial lipopolysaccharides (LPS). IVIg is a polyvalent antibody, primarily immunoglobulin Gs (IgGs), pooled from the plasma of more than 1,000 blood donors. It is used to supplement antibodies in patients with immune deficiencies or to suppress immune responses in patients with autoimmune or inflammatory conditions. Infliximab, a therapeutic anti-tumor necrosis factor alpha (TNF&#945;) antibody, has also been shown to activate macrophages to produce IL-10 in response to inflammatory stimuli. IVIg and other antibody-based biologics can be tested to determine their effects on macrophage activation. This paper describes methods for derivation, stimulation, and assessment of murine bone marrow macrophages activated by antibodies in vitro and murine peritoneal macrophages activated with antibodies in vivo. Finally, we demonstrate the use of western blotting to determine the contribution of specific cell signaling pathways to anti-inflammatory macrophage activity. These protocols can be used with genetically modified mice, to determine the effect of a specific protein(s) on anti-inflammatory macrophage activation. These techniques can also be used to assess whether specific biologics may act by changing macrophages to an IL-10-producing anti-inflammatory activation state that reduces inflammatory responses in vivo. This can provide information on the role of macrophage activation in the efficacy of biologics during disease models in mice, and provide insight into a potential new mechanism of action in people. Conversely, this may caution against the use of specific antibody-based biologics to treat infectious disease, particularly if macrophages play an important role in host defense against that infection.

Antibody-based drugs have revolutionized treatment for inflammatory diseases. In addition to having direct effects on specific targets, antibodies can activate macrophages to become anti-inflammatory. This protocol describes how anti-inflammatory macrophage activation can be assessed in vitro, using mouse bone marrow macrophages, and in vivo, using peritoneal macrophages.

Macrophages are phagocytic innate immune cells, which initiate immune responses to pathogens and contribute to healing and tissue restitution. Macrophages ...

Generation of Organ-conditioned Media and Applications for Studying Organ-specific Influences on Breast Cancer Metastatic Behavior

Breast cancer preferentially metastasizes to the lymph node, bone, lung, brain and liver in breast cancer patients. Previous research efforts have focused on identifying factors inherent to breast cancer cells that are responsible for this observed metastatic pattern (termed organ tropism), however much less is known about factors present within specific organs that contribute to this process. This is in part because of a lack of in vitro model systems that accurately recapitulate the organ microenvironment. To address this, an ex vivo model system has been established that allows for the study of soluble factors present within different organ microenvironments. This model consists of generating conditioned media from organs (lymph node, bone, lung, and brain) isolated from normal athymic nude mice. The model system has been validated by demonstrating that different breast cancer cell lines display cell-line specific and organ-specific malignant behavior in response to organ-conditioned media that corresponds to their in vivo metastatic potential. This model system can be used to identify and evaluate specific organ-derived soluble factors that may play a role in the metastatic behavior of breast and other types of cancer cells, including influences on growth, migration, stem-like behavior, and gene expression, as well as the identification of potential new therapeutic targets for cancer. This is the first ex vivo model system that can be used to study organ-specific metastatic behavior in detail and evaluate the role of specific organ-derived soluble factors in driving the process of cancer metastasis.

This manuscript describes an ex vivo model system comprised of organ-conditioned media derived from the lymph node, bone, lung, and brain of mice. This model system can be used to identify and study organ-derived soluble factors and their effects on the organ tropism and metastatic behavior of cancer cells.

Breast cancer preferentially metastasizes to the lymph node, bone, lung, brain and liver in breast cancer patients. Previous research efforts have focused ...

Medicine

A Comprehensive High-Efficiency Protocol for Isolation, Culture, Polarization, and Glycolytic Characterization of Bone Marrow-Derived Macrophages

Macrophages are among the most important antigen-presenting cells. Many subsets of macrophages have been identified with unique metabolic signatures. Macrophages are commonly classified as M1-like (inflammatory) and M2-like (anti-inflammatory) subtypes. M1-like macrophages are pro-inflammatory macrophages that get activated by LPS and/or pro-inflammatory cytokines such as INF-&#947;, IL-12 &#38; IL-2. M1-like polarized macrophages are involved in various diseases by mediating the host&#39;s defense to a variety of bacteria and viruses. That is very important to study LPS induced M1-like macrophages and their metabolic states in inflammatory diseases. M2-like macrophages are considered anti-inflammatory macrophages, activated by anti-inflammatory cytokines and stimulators. Under the pro-inflammatory state, macrophages show increased glycolysis in glycolytic function. The glycolytic function has been actively investigated in the context of glycolysis, glycolytic capacity, glycolytic reserve, compensatory glycolysis, or non-glycolytic acidification using extracellular flux (XF) analyzers.
This paper demonstrates how to assess the glycolytic states in real-time with easy-to-follow steps when the bone marrow-derived macrophages (BMDMs) are respiring, consuming, and producing energy. Using specific inhibitors and activators of glycolysis in this protocol, we show how to obtain a systemic and complete view of glycolytic metabolic processes in the cells and provide more accurate and realistic results. To be able to measure multiple glycolytic phenotypes, we provide an easy, sensitive, DNA-based normalization method for polarization assessment of BMDMs. Culturing, activation/polarization and identification of the phenotype and metabolic state of the BMDMs are crucial techniques that can help to investigate many different types of diseases.
In this paper, we polarized the na&#239;ve M0 macrophages to M1-like and M2-like macrophages with LPS and IL4, respectively, and measured a comprehensive set of glycolytic parameters in BMDMs in real-time and longitudinally over time, using extracellular flux analysis and glycolytic activators and inhibitors.

This protocol provides detailed and comprehensive methods for the isolation, culture, polarization, and measurement of the glycolytic metabolic state of live bone marrow-derived macrophages (BMDMs). This paper provides step-by-step instructions with realistic visual illustrations for workflow and glycolytic assessment of BMDMs in real-time.

Macrophages are among the most important antigen-presenting cells. Many subsets of macrophages have been identified with unique metabolic signatures. ...

Evaluation of Caspase Activation to Assess Innate Immune Cell Death

Innate immunity provides the critical first line of defense in response to pathogens and sterile insults. A key mechanistic component of this response is the initiation of innate immune programmed cell death (PCD) to eliminate infected or damaged cells and propagate immune responses. However, excess PCD is associated with inflammation and pathology. Therefore, understanding the activation and regulation of PCD is a central aspect of characterizing innate immune responses and identifying new therapeutic targets across the disease spectrum.
This protocol provides methods for characterizing innate immune PCD activation by monitoring caspases, a family of cysteine-dependent proteases that are often associated with diverse PCD pathways, including&#160;apoptosis,&#160;pyroptosis, necroptosis, and PANoptosis. Initial reports characterized caspase-2, caspase-8, caspase-9, and caspase-10 as initiator caspases and caspase-3, caspase-6, and caspase-7 as effector caspases in apoptosis, while later studies found the inflammatory caspases, caspase-1, caspase-4, caspase-5, and caspase-11, drive pyroptosis. It is now known that there is extensive crosstalk between the caspases and other innate immune and&#160;cell death molecules across the previously defined PCD pathways, identifying a key knowledge gap in the mechanistic understanding of innate immunity and PCD and&#160;leading to the characterization of PANoptosis. PANoptosis is a unique innate immune inflammatory PCD pathway regulated by PANoptosome complexes, which integrate components, including caspases,&#160;from other cell death pathways.
Here, methods for assessing the activation of caspases in response to various stimuli are provided. These methods allow for the characterization of PCD pathways both in vitro and in vivo, as activated caspases undergo proteolytic cleavage that can be visualized by western blotting using optimal antibodies and blotting conditions. A protocol and western blotting workflow have been established that allow for the assessment of the activation of multiple caspases from the same cellular population, providing a comprehensive characterization of the PCD processes. This method can be applied across research areas in development, homeostasis, infection, inflammation, and cancer to evaluate PCD pathways throughout cellular processes in health and disease.

This protocol describes a comprehensive method for assessing caspase activation (caspase-1, caspase-3, caspase-7, caspase-8, caspase-9, and caspase-11) in response to both in vitro and in vivo (in mice) models of infection, sterile insults, and cancer to determine the initiation of cell death pathways, such as pyroptosis, apoptosis, necroptosis, and PANoptosis.

Innate immunity provides the critical first line of defense in response to pathogens and sterile insults. A key mechanistic component of this response is ...

Isolation and Cultivation of Mandibular Bone Marrow Mesenchymal Stem Cells in Rats

Here we present an efficient method for isolating and culturing mandibular bone marrow mesenchymal stem cells (mBMSCs) in vitro to rapidly obtain numerous high-quality cells for experimental requirements. mBMSCs could be widely used in therapeutic applications as tissue engineering cells in case of craniofacial diseases and cranio-maxillofacial regeneration in the future due to the excellent self-renewal ability and multi-lineage differentiation potential. Therefore, it is important to obtain mBMSCs in large numbers.
In this study, bone marrow was flushed from the mandible and primary mBMSCs were isolated through whole bone marrow adherent cultivation. Furthermore, CD29+CD90+CD45&#8722; mBMSCs were purified through fluorescent cell sorting. The second generation of purified mBMSCs were used for further study and displayed potential in differentiating into osteoblasts, adipocytes, and chondrocytes. Utilizing this in vitro model, one can obtain a high number of proliferative mBMSCs, which may facilitate the study of the biological characteristics, the subsequent reaction to the microenvironment, and other applications of mBMSCs.

This article presents a method that combines whole bone marrow adherence and flow cytometry sorting for isolating, cultivating, sorting, and identifying bone marrow mesenchymal stem cells from rat mandibles.

Here we present an efficient method for isolating and culturing mandibular bone marrow mesenchymal stem cells (mBMSCs) in vitro to rapidly obtain numerous ...

Using Real-Time Cell Metabolic Flux Analyzer to Monitor Osteoblast Bioenergetics

Bone formation by osteoblasts is an essential process for proper bone acquisition and bone turnover to maintain skeletal homeostasis, and ultimately, prevent fracture. In the interest to both optimize peak bone mass and combat various musculoskeletal diseases (i.e., post-menopausal osteoporosis, anorexia nervosa, type 1 and 2 diabetes mellitus), incredible efforts have been made in the field of bone biology to fully characterize osteoblasts throughout their differentiation process. Given the primary role of mature osteoblasts to secrete matrix proteins and mineralization vesicles, it has been noted that these processes take an incredible amount of cellular energy, or adenosine triphosphate (ATP). The overall cellular energy status is often referred to as cellular bioenergetics, and it includes a series of metabolic reactions that sense substrate availability to derive ATP to meet cellular needs. Therefore, the current method details the process of isolating primary, murine bone marrow stromal cells (BMSCs) and monitoring their bioenergetic status using the Real-time cell metabolic flux analyzer at various stages in osteoblast differentiation. Importantly, these data have demonstrated that the metabolic profile changes dramatically throughout osteoblast differentiation. Thus, using this physiologically relevant cell type is required to fully appreciate how a cell's bioenergetic status can regulate the overall function.

Real-time cell metabolic flux assay measures the oxygen consumption rate and extracellular acidification rate, which corresponds to mitochondrial and glycolytic adenosine triphosphate production, using pH and oxygen sensors. The manuscript explains a method to understand the energy status of osteoblasts and the characterization and interpretation of the cellular bioenergetic status.

Bone formation by osteoblasts is an essential process for proper bone acquisition and bone turnover to maintain skeletal homeostasis, and ultimately, ...

Bone Conditioned Medium: Preparation and Bioassay

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Generation of Organ-conditioned Media and Applications for Studying Organ-specific Influences on Breast Cancer Metastatic Behavior

A Comprehensive High-Efficiency Protocol for Isolation, Culture, Polarization, and Glycolytic Characterization of Bone Marrow-Derived Macrophages

Evaluation of Caspase Activation to Assess Innate Immune Cell Death

Isolation and Cultivation of Mandibular Bone Marrow Mesenchymal Stem Cells in Rats

Using Real-Time Cell Metabolic Flux Analyzer to Monitor Osteoblast Bioenergetics