Name: isolation and purification of fungal &#946;-glucan as an immunotherapy strategy for glioblastoma
Uploaded: 2023-06-02T14:20:00
Description: Watch this Scientific Journal Video about Isolation and Purification of Fungal Î²-Glucan as an Immunotherapy Strategy for Glioblastoma at JoVE.com

We would like to thank Dr Vasiliki Economopoulos for her in-house script to measure the fuluorescence signal in ImageJ. We would also want to thank the CITIUS (University of Seville) and all their personnel for their support during the demonstration. This work was supported by the Spanish FEDER I + D + i-USE, US-1264152 from University of Seville, and the Ministerio de Ciencia, Innovaci&#243;n y Universidades PID2021-126090OA-I00

The four different mushroom variants described in this protocol were obtained from a commercial source (see Table of Materials).
1. Isolation of fungal &#946;-glucans
<ol>
	<li>Extraction and isolation of soluble mushroom polysaccharides 
	NOTE: Soluble mushroom polysaccharides (SMPs) were obtained according to the procedure schematically shown in Figure 1.
	<ol>
		<li>Gently rinse fresh P. ostreatus, P. djamor...

<ol>
	<li>Aldape, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+to+curing+primary+brain+tumours.">Challenges to curing primary brain tumours.</a> Nature Reviews. Clinical Oncology. 16 (8), 509-520 (2019).</li><li>Himes, B. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunosuppression+in+glioblastoma:+current+understanding+and+therapeutic+implications.">Immunosuppression in glioblastoma: current understanding and therapeutic implications.</a> Frontiers in Oncology. 11, 770561 (2021).</li><li>Ma, J., Chen, C. C., Li, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophages/microglia+in+the+glioblastoma+tumor+microenvironment.">Macrophages/microglia in the glioblastoma tumor microenvironment.</a> International Journal of Molecular Sciences. 22 (11), 5775 (2021).</li><li>Sevenich, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Turning+&amp;#34;cold&amp;#34;+into+&amp;#34;hot&amp;#34;+tumors-opportunities+and+challenges+for+radio-immunotherapy+against+primary+and+metastatic+brain+cancers.">Turning &amp;#34;cold&amp;#34; into &amp;#34;hot&amp;#34; tumors-opportunities and challenges for radio-immunotherapy against primary and metastatic brain cancers.</a> Frontiers in Oncology. 9, 163 (2019).</li><li>Niesel, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immune+suppressive+microenvironment+affects+efficacy+of+radio-immunotherapy+in+brain+metastasis.">The immune suppressive microenvironment affects efficacy of radio-immunotherapy in brain metastasis.</a> EMBO Molecular Medicine. 13 (5), e13412 (2021).</li><li>McCann, F., Carmona, E., Puri, V., Pagano, R. E., Limper, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophage+internalization+of+fungal+beta-glucans+is+not+necessary+for+initiation+of+related+inflammatory+responses.">Macrophage internalization of fungal beta-glucans is not necessary for initiation of related inflammatory responses.</a> Infection and Immunity. 73 (10), 6340-6349 (2005).</li><li>Vetvicka, V., Teplyakova, T. V., Shintyapina, A. B., Korolenko, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+medicinal+fungi-derived+&#946;-glucan+on+tumor+progression.">Effects of medicinal fungi-derived &#946;-glucan on tumor progression.</a> Journal of Fungi. 7 (4), 250 (2021).</li><li>Chan, G. C. F., Chan, W. K., Sze, D. M. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effects+of+beta-glucan+on+human+immune+and+cancer+cells.">The effects of beta-glucan on human immune and cancer cells.</a> Journal of Hematology &amp; Oncology. 2, 25 (2009).</li><li>Lowry, O. H., Rosebrough, N. J., Farr, A. L., Randall, R. 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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=STAT3-mediated+astrocyte+reactivity+associated+with+brain+metastasis+contributes+to+neurovascular+dysfunction.">STAT3-mediated astrocyte reactivity associated with brain metastasis contributes to neurovascular dysfunction.</a> Cancer Research. 80 (24), 5642-5655 (2020).</li><li>Chrom&#253;, V., Vinkl&#225;rkov&#225;, B., &#352;prongl, L., Bittov&#225;, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Kjeldahl+method+as+a+primary+reference+procedure+for+total+protein+in+certified+reference+materials+used+in+clinical+chemistry.+I.+A+review+of+Kjeldahl+methods+adopted+by+laboratory+medicine.">The Kjeldahl method as a primary reference procedure for total protein in certified reference materials used in clinical chemistry. I. A review of Kjeldahl methods adopted by laboratory medicine.</a> Critical Reviews in Analytical Chemistry. 45 (2), 106-111 (2015).</li><li>Waterborg, J. H., Matthews, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Lowry+method+for+protein+quantitation.">The Lowry method for protein quantitation.</a> Methods in Molecular Biology. 32, 1-4 (1994).</li><li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+and+antioxidant+activities+of+polysaccharides+from+thirteen+boletus+mushrooms.">Characterization and antioxidant activities of polysaccharides from thirteen boletus mushrooms.</a> International Journal of Biological Macromolecules. 113, 1-7 (2018).</li><li>Barbosa, J. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Obtaining+extracts+rich+in+antioxidant+polysaccharides+from+the+edible+mushroom+Pleurotus+ostreatus+using+binary+system+with+hot+water+and+supercritical+CO2.">Obtaining extracts rich in antioxidant polysaccharides from the edible mushroom Pleurotus ostreatus using binary system with hot water and supercritical CO2.</a> Food Chemistry. 330, 127173 (2020).</li><li>Ma, Y. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+polysaccharides+from+mycelia+of+genus+Ganoderma+by+mid-infrared+and+near-infrared+spectroscopy.">Assessment of polysaccharides from mycelia of genus Ganoderma by mid-infrared and near-infrared spectroscopy.</a> Scientific Reports. 8 (1), 10 (2018).</li><li>Nie, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immune-enhancing+effects+of+polysaccharides+MLN-1+from+by-product+of+Mai-luo-ning+in+vivo+and+in+vitro.">Immune-enhancing effects of polysaccharides MLN-1 from by-product of Mai-luo-ning in vivo and in vitro.</a> Food and Agricultural Immunology. 30 (1), 369-384 (2019).</li><li>Cerletti, C., Esposito, S., Iacoviello, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Edible+mushrooms+and+beta-glucans:+impact+on+human+health.">Edible mushrooms and beta-glucans: impact on human health.</a> Nutrients. 13 (7), 2195 (2021).</li><li>Klaus, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+edible+mushroom+Laetiporus+sulphureus+as+potential+source+of+natural+antioxidants.">The edible mushroom Laetiporus sulphureus as potential source of natural antioxidants.</a> International Journal of Food Sciences and Nutrition. 64 (5), 599-610 (2013).</li><li>Kozarski, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dietary+polysaccharide+extracts+of+Agaricus+brasiliensis+fruiting+bodies:+chemical+characterization+and+bioactivities+at+different+levels+of+purification.">Dietary polysaccharide extracts of Agaricus brasiliensis fruiting bodies: chemical characterization and bioactivities at different levels of purification.</a> Food Research International. 64, 53-64 (2014).</li><li>Ayimbila, F., Keawsompong, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+composition+and+antioxidant+property+of+crude+polysaccharides+from+the+fruiting+bodies+of+Lentinus+squarrosulus.">Functional composition and antioxidant property of crude polysaccharides from the fruiting bodies of Lentinus squarrosulus.</a> 3 Biotech. 11 (1), 7 (2021).</li><li>de Azambuja, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ki-67+as+prognostic+marker+in+early+breast+cancer:+a+meta-analysis+of+published+studies+involving+12,155+patients.">Ki-67 as prognostic marker in early breast cancer: a meta-analysis of published studies involving 12,155 patients.</a> British Journal of Cancer. 96 (10), 1504-1513 (2007).</li><li>Holubec, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+apoptosis+by+immunohistochemical+markers+compared+to+cellular+morphology+in+ex+vivo-stressed+colonic+mucosa.">Assessment of apoptosis by immunohistochemical markers compared to cellular morphology in ex vivo-stressed colonic mucosa.</a> The Journal of Histochemistry and Cytochemistry. 53 (2), 229-235 (2005).</li><li>Borges, G. 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This work describes the use of well-established techniques to successfully isolate, purify, and characterize the content of S&#946;Gs from four different fungi. The results showed how after hot water extraction of SMPs, obtained from P. ostreatus, P. djamor, G. lucidum, and H. erinaceus,&#160;followed by hydrolytic treatment with &#945;-amylase, glucosidase, and protease, the content of &#945;-glucan and protein were reduced, thus significantly enriching the amount of pure S&#946;Gs.</...

Despite the advent of novel achievements in the field of neuro-oncology, the life expectancy of glioblastoma patients remains meager. Gold-standard therapies against brain tumors are based on the amalgamation of surgery, radiotherapy, and chemotherapy. However, in the last decade, immunotherapy has emerged as a powerful strategy to treat different types of cancer1. Thus, the possibility of harnessing the body&#39;s immune response against tumor cells has recently become the fourth pillar of oncology.
It has long been known that one of the biggest challenges in the field is to overcome the strong immunosuppression found within the tumor microenvironment2. Particularly, in the case of glioblastoma, one of the most common and aggressive forms of brain cancer, unraveling key pathways that orchestrate such pro-tumoral scenarios and finding novel compounds that could counteract the depressing response of the immune system might pave the way for future therapies against this incurable disease.
The brain possesses its own immune system cells, and the most relevant cell type are microglia. These cells have been proven to have a rather complex behavior across different central diseases3. In the case of primary brain tumors (e.g., glioblastoma), these cells are shifted toward an anti-inflammatory phenotype that supports tumor cells to colonize the brain parenchyma3. Numerous publications have enhanced the major role of these cells during tumor progression. One of the main reasons for this is that glioma-associated microglia and infiltrated macrophages (GAMs) account for one-third of the total tumor mass, thus suggesting the unequivocal influence of their activation states during brain tumor progression4,5.
In that vein, fungal &#946;-glucans have been described as potent molecules triggering effective immune responses, including phagocytosis and pro-inflammatory factors production, leading to the elimination of pernicious agents6,7,8,9,10. Fungal &#946;-glucans have generally been studied using extracts from different mushroom parts. However, the attribution of specific effects requires its purification to avoid ambiguities and to be able to understand the mechanism of action of such molecules as immunomodulatory agents8.
In this work, soluble &#946;-glucans are purified from the fruiting body of four different mushrooms, regularly employed as edible (Pleurotus ostreatus and Pleurotus djamor) and as medicinal (Ganoderma lucidum and Hericium erinaceus) mushrooms. In particular, these four mushrooms have great use in the food and pharmaceutical industry and were produced within an environmentally friendly circular economy in a commercial enterprise (see Table of Materials).
In order to lay the foundation for the future use of fungal &#946;-glucans in brain cancer therapies, well-defined purification strategies and preclinical studies delving into their putative interaction with immune system cells are essential to evaluate their potential role as anti-tumor mediators. This work describes the numerous steps of isolation and purification needed to retrieve the soluble &#946;-glucans contained within the fruiting bodies of the selected mushroom. Once successfully purified, microglia cells are activated to enhance their inflammatory phenotype. Mouse glioblastoma cells (GL261) are coated with a different microglia-conditioned medium, previously treated with these extracts, and then its effect on tumor cells&#39; behavior is evaluated. Interestingly, pilot studies from our lab (data not shown) have uncovered how pro-inflammatory microglia may slow tumor cell migration and invasion properties not only in glioblastoma cells but also in other cancer cell lines. This multidisciplinary work may provide a useful tool for oncology researchers to test promising compounds able to boost the immune response in many different types of tumors.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>8-well chamber slides</td>
			<td>Thermo Fisher, USA</td>
			<td>171080</td>
			<td></td>
		</tr>
		<tr>
			<td>Air-drying oven</td>
			<td>J.P. Selecta S.A., Spain</td>
			<td>2000210</td>
			<td></td>
		</tr>
		<tr>
			<td>Albumin</td>
			<td>Sigma-Aldrich, St. Louis</td>
			<td>A7030</td>
			<td></td>
		</tr>
		<tr>
			<td>Alcalase</td>
			<td>Novozymes, Denmark</td>
			<td>protease</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa Fluor 488</td>
			<td>Thermofisher, USA</td>
			<td>A32731</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa Fluor 647</td>
			<td>Thermofisher, USA</td>
			<td>A32728</td>
			<td></td>
		</tr>
		<tr>
			<td>Blade mill</td>
			<td>Retsch, Germany</td>
			<td>&#160;SM100</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>MERK, Germany</td>
			<td>A9418</td>
			<td></td>
		</tr>
		<tr>
			<td>Cellulose tubing membrane</td>
			<td>Sigma-Aldrich, St. Louis</td>
			<td>D9402</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>MERK, Germany</td>
			<td>Eppendorf, 5810R</td>
			<td></td>
		</tr>
		<tr>
			<td>Colocalisation pluggins</td>
			<td>ImageJ</td>
			<td></td>
			<td>(https://imagej.net/imaging/colocalization-analysis&#160;)</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>MERK, Germany</td>
			<td>28718-90-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Dextrans</td>
			<td>Pharmacosmos, Holbalk, Denmark</td>
			<td>Dextran 410, 80, 50</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#180;s modified Eagle&#180;s medium, Gluta MAXTM</td>
			<td>Gibco, Life Technologies, Carlsbad, CA, USA</td>
			<td>10564011</td>
			<td></td>
		</tr>
		<tr>
			<td>Extenda (&#945;- Amylase/Glucoamylase)</td>
			<td>Novozymes, Denmark</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Gibco, Life Technologies, Carlsbad, CA, USA</td>
			<td>A4736301</td>
			<td></td>
		</tr>
		<tr>
			<td>FT-IR spectromete</td>
			<td>Bruker-Vertex, Switzerland</td>
			<td>VERTEX 70v</td>
			<td></td>
		</tr>
		<tr>
			<td>Graphing and analysis software</td>
			<td>GraphPad Prism (GraphPad Software, Inc.)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>H2SO4</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>HPLC system</td>
			<td>Waters Corp, Milford, MA, USA</td>
			<td>Waters 2695 HPLC</td>
			<td></td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Eppedorf</td>
			<td>Galaxy 170S</td>
			<td></td>
		</tr>
		<tr>
			<td>Mass Spectometer</td>
			<td>Q Exactive GC, Thermo Scientific</td>
			<td>725500</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>MERK, Germany</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin</td>
			<td>Sigma-Aldrich, St. Louis</td>
			<td>P4458</td>
			<td></td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>Crison, Barcelona, Spain</td>
			<td>Basic 20</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline</td>
			<td>Gibco, Life Technologies, Carlsbad, CA, USA</td>
			<td>1010-015</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit Cleaved Caspase-3 (Asp175) Antibody</td>
			<td>Abcam, UK</td>
			<td>ab243998</td>
			<td></td>
		</tr>
		<tr>
			<td>Rat Ki-67 Monoclonal</td>
			<td>Thermofisher, USA</td>
			<td>MA5-14520</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotary evaporator</td>
			<td>B&#252;chi Ib&#233;rica S.L.U., Spain</td>
			<td>El Rotavapor R-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultra-hydrogel linear gel-filtration column (300 mm x 7.8 mm)</td>
			<td>Waters Corp, Milford, MA, USA</td>
			<td>WAT011545</td>
			<td></td>
		</tr>
		<tr>
			<td>UV-Visible spectrophotometer</td>
			<td>Amersham Bioscience, UK</td>
			<td>Ultrospec 2100 pro</td>
			<td></td>
		</tr>
		<tr>
			<td>VectaMount</td>
			<td>Vector Laboratories, C.A, USA</td>
			<td>H-5000-60</td>
			<td></td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>J.P. Selecta S.A., Spain</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Zeiss LSM 7 DUO Confocal Microscope System.</td>
			<td>Zeiss, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>&#946;-glucan Assay Kit</td>
			<td>Megazyme, Bray, Co. Wicklow, Ireland</td>
			<td>K-BGLU</td>
			<td></td>
		</tr>
		<tr>
			<td>&#946;-glucans</td>
			<td>Setas y Hongos del Sur, S.L.</td>
			<td></td>
			<td>Supplied the four variants of mushrooms</td>
		</tr>
	</tbody>
</table>

isolation and purification of fungal &#946;-glucan as an immunotherapy strategy for glioblastoma

One of the biggest challenges in developing effective therapies against glioblastoma is overcoming the strong immune suppression within the tumor microenvironment. Immunotherapy has emerged as an effective strategy to turn the immune system response against tumor cells. Glioma-associated macrophages and microglia (GAMs) are major drivers of such anti-inflammatory scenarios. Therefore, enhancing the anti-cancerous response in GAMs may represent a potential co-adjuvant therapy to treat glioblastoma patients. In that vein, fungal &#946;-glucan molecules have long been known as potent immune modulators. Their ability to stimulate the innate immune activity and improve treatment response has been described. Those modulating features are partly attributed to their ability to bind to pattern recognition receptors, which, interestingly, are greatly expressed in GAMs. Thus, this work is focused on the isolation, purification, and subsequent use of fungal &#946;-glucans to enhance the tumoricidal response of microglia against glioblastoma cells. The mouse glioblastoma (GL261) and microglia (BV-2) cell lines are used to test the immunomodulatory properties of four different fungal &#946;-glucans extracted from mushrooms heavily used in the current biopharmaceutical industry: Pleurotus ostreatus, Pleurotus djamor, Hericium erinaceus,&#160;and Ganoderma lucidum. To test these compounds, co-stimulation assays were performed to measure the effect of a pre-activated microglia-conditioned medium on the proliferation and apoptosis activation in glioblastoma cells.

Successful purification of &#946;-glucans 
The mass of MP, SMPs, and S&#946;Gs obtained from fruiting bodies of P. ostreatus, P. djamor, G. lucidum, and H. erinaceus following the extraction and purification process is summarised in Table 1. The basic composition (total carbohydrates, &#946;-glucans, and protein) of MP, SMPs, and S&#946;Gs obtained from the fungi is depicted in Table 2. These results show how the protocol allowed ...

Watch this Scientific Journal Video about Isolation and Purification of Fungal Î²-Glucan as an Immunotherapy Strategy for Glioblastoma at JoVE.com

Isolation and Purification of Fungal &#946;-Glucan as an Immunotherapy Strategy for Glioblastoma

The present protocol describes the purification steps and subsequent studies of four different fungal &#946;-glucans as potential immunomodulatory molecules that enhance the anti-tumoral properties of microglia against glioblastoma cells.

One of the biggest challenges in developing effective therapies against glioblastoma is overcoming the strong immune suppression within the tumor ...

Fungal beta-glucans are important modulators of the immune system. Enhancing the purity and isolation protocols is essential to asserting their potential role as co-adjuvants for cancer therapy. A high degree of four different beta-glucans was achieved using various devices commonly found in molecular biology and proteomic laboratories.This protocol focuses on testing the effects of beta-glucans on microglia, the brain's most abundant resident immune cell. Modulating the microglia phenotype in glioblastoma can yield in important insights into. Begin the extraction of soluble mushroom polysaccharides or SMPs by rinsing fresh fruiting bodies of Pleurotus ostreatus, Pleurotus djamor, Hericium erinaceus, and Ganoderma lucidum with distilled water five times.Then dry the washed fruiting bodies completely at 50 degrees Celsius in a conventional air drying oven for approximately 24 hours before grinding them in a blade mill obtaining about 200 grams of powder from each mushroom. Next, suspend 100 grams of all four mushroom powders or MP in 1, 000 milliliters of distilled water and autoclave the suspension at 121 degrees Celsius for 15 minutes. After 30 minutes of incubation at room temperature, centrifuge the resulting suspension at 6, 000 G for 10 minutes at four degrees Celsius.Then dry the precipitate containing insoluble mushroom polysaccharides or IMPs at 50 degrees Celsius in an air drying oven for 24 hours. Discard the precipitate and concentrate the supernatant 10 times in a rotary evaporator. Next, precipitate the concentrate containing SMPs with ethanol overnight at four degrees Celsius.After centrifuging the ethanol suspension at 6, 000 G for 15 minutes at four degrees Celsius, discard the supernatant with a pipette and wash the pellet three times with 80%ethanol before dissolving it and distilled water. Adjust the pH to 6.5 to 7 and the temperature to 37 degrees Celsius and solubilize the alpha-glucans by treating the suspension with two units and four units of alpha-amylase and glucoamylase respectively. Next, adjust the pH to 8.0 and temperature to 50 degrees Celsius and solubilize the proteins by treating the suspension with alkalase equivalent to 2.5 units per gram of protein.After hydrolysis, centrifuge the hydrolysate and clean the supernatant concentrate five times in a rotary evaporator. Precipitate the supernatant concentrate again by adding 80%ethanol. To remove low molecular weight molecules, solubilize the precipitate in distilled water and dialyze it in the distilled water for 24 hours using 12, 000 Dalton cutoff cellulose tubing membranes.Recover the water soluble portion and freeze dry it to produce soluble beta-glucans or S beta-Gs. Evaluate the total glucans and alpha-glucans separately. Measure the resulting beta-glucan values as the difference between the total glucan and alpha-glucan values.To obtain the S beta-G UV spectra using a UV visible spectrophotometer, prepare 1.0 milligram per milliliter of each S beta-G in distilled water. Transfer the sample to a quartz cuvette and scan at room temperature in the 200 to 400 nanometers region. Estimate the homogeneity of S beta-Gs and molecular weight of polymers by size exclusion chromatography or SEC using a high performance liquid chromatography or HPLC system equipped with a UV visible detector and a Superdex TM 200 10/300 GL gel filtration column.Record the infrared spectra of the sample on a Fourier-transform infrared or FTIR spectrometer in the 4, 000 to 500 per centimeter range. Activate the microglia by coating the BV2 microglia cells for 72 hours with 0.2 milligrams per milliliter concentration of four different beta-glucans isolated from P.ostreatus, P.djamor, G.lucidum, and H.erinaceus. After 72 hours, collect the supernatant with a pipette and pass the remaining volume through a 0.20 micrometer syringe filter.Then freeze the supernatant at minus 80 degrees Celsius for at least 24 hours. To treat GL 261 with the pre-activated microglia conditioned medium, add 250 microliters of beta-glucan-treated microglial medium to 80%confluent GL 261 cells for 72 hours. Discard the medium after 72 hours.UV spectra of the different S beta-Gs did not show UV absorption peaks at 260 and 280 nanometers, indicating that S beta-Gs lacked nucleic acids and proteins. The HPLC chromatograms showed good homogeneity with a main sharp and single peak at 10.9 minutes for P.ostreatus, 10.5 minutes for lucidum, 11.3 minutes for P.djamor, and 8.20 minutes for H.erinaceus, suggesting the fraction is consistent with homopolymers. The FTIR spectra measured the molecular vibrations corresponding to covalent polysaccharide bonds.It showed that SS beta-Gs comprised carbohydrates conjugated with a minimal protein. HPTLC and GC-MS analyzing the monosaccharide profile of S beta-Gs revealed the presence of a large amount of D-glucose, smaller amounts of D-galactose and D-mannose, and a trace of D-xylose, D-rhamnose, D-fucose, and L-arabinose. Using an in-house script in ImageJ software, the number of positive pixels for each fluorescent channel was quantified.The script used control samples as a threshold for the intensity of each fluorophore and provided the number of pixels. It indicated the expression for each marker after different experimental conditions. Interestingly, GL 261 did not suffer significant differences regarding tumor proliferation on exposure to the different microglia conditioned media.However, P.djamor and H.erinaceus showed strong induction of an approximately sixfold and ninefold increase in cleaved caspase-3 respectively. Ensuring a high-grade purity of beta-glucans is essential for this protocol. This protocol uses advanced equipment such as spectrophotometer, HPLC.or FITR. Using these tools enhance the robustness of our findings. We can confidently analyze the effects of beta-glucans on microglia and obtain more confident results.Owing to time and world limitation, we have restricted our protocol to the study of beta-glucans on microglial cells. However, other cells from the immune system such as macrophages or T cells can be easily easily during this protocol. For the first time, these protocols combine two different area of knowledge.First, the use of biotechnological procedure to purify specific products, and second, the use of cell culture techniques to test their immunomodulatory properties.

Research

JoVE Journal

Neuroscience

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