Name: evaluation of the efficacy and toxicity of rnas targeting hiv-1 production for use in gene or drug therapy
Uploaded: 2016-09-05T14:00:00.000+00:00
Duration: 12 min 3 s
Description: Watch this Scientific Journal Video about Evaluation of the Efficacy And Toxicity of RNAs Targeting HIV-1 Production for Use in Gene or Drug Therapy at JoVE.com

העבודה המוצגת כאן נתמכה על ידי המכון הקנדי לבריאות מחקר (CIHR) (מעניק DCB-120,266, PPP-133,377 ו HBF-348,967 ל AG).

1. תאי transfections <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> תרבות תאי HEK 293T במדיום הנשר השונה של Dulbecco (DMEM) בתוספת 10% בסרום שור עוברי (FBS) ו -1% פניצילין / סטרפטומיצין. כן השעית 2 x 10 5 תאים / מיליליטר במדיום תרבית תאים. הוספת 500, 100 ו -1,000 μl של השעיה התא היטב כל 24 גם, 96-היטב צלחות 12-היטב, לייצור ויראלי, כדאיות התא מבחני ההפעלה החיסונית, בהתאמה (איור 2 א). </li><li style=";text-align:right;direction:rtl"> מערבולת בעדינות את הצלחות דגירה אותם O / N ב 37 מעלות צלזיוס עם 5% CO 2. לגדל תאים כדי 50-70% confluency. </li><li style=";text-align:right;direction:rtl"> על פי תוכנית transfection, להכין דילולים של RNAs מבחן ובקרות שלהם ב 1.5 צינורות מיקרו מ&quot;ל (דוגמה, איור 2B). <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> עבור assay הייצור ויראלי, להכין 10 ng / דילול μl של פלסמיד ביטוי HIV-1 ולהוסיף 10 μl על צינור אחד. הבא להכין 5 מיקרומטר דילולים של RNAs הניסיוני RN בקרה שליליא להוסיף 2.5 או 10 μl של כל RNA מבחן ודילול בקרה שלילי על הצינורות המקביל עבור 25 או 100 ריכוזים סופיים ננומטר. </li><li style=";text-align:right;direction:rtl"> עבור assay כדאיות התא, להכין 5 מיקרומטר דילולים של RNAs הבדיקה דילול 10 מ&quot;ג / מ&quot;ל ​​של RNA בקרה חיובית, משקל מולקולרי נמוך אני פוליפוני: C. הוסף 2 μl של רנ&quot;א בדיקה או דילולי RNA הבקרה חיוביים על הצינורות המתאימים עבור 100 ננומטר או 200 ריכוזים סופיים מיקרוגרם / מיליליטר, בהתאמה. </li><li style=";text-align:right;direction:rtl"> עבור assay ההפעלה החיסוני, להוסיף 20 μl של רנ&quot;א בדיקה או דילולי RNA בקרה חיוביים מוכנים בשלב 1.3.2. אל הצינורות המתאימים עבור 100 ננומטר או 200 מיקרוגרם / ריכוזיים סופי מיליליטר, בהתאמה. הערה: פלסמידים ביטוי RNA בדיקות, להכין 10 ng / דילולים μl במקום של 5 מיקרומטר דילולים של RNAs הבדיקה, מתן הסכומים הסופיים של 25 ו -100 ng עבור צעד 1.3.1. ו -100 ng לצעדים 1.3.2. ו 1.3.3. </li></ol></li><li style=";text-align:right;direction:rtl"> הוסף 50, 25 או 75 μl של DMEM על צינור אחד transfection למוצרים ויראליuction, כדאיות התא מבחני ההפעלה החיסונית, בהתאמה. מבחני ההפקה ויראלי, להביא תאים וצינורות transfection מוכן מעבדה ביו בטיחות ברמה 3 (BSL3) לפני השלב הבא. </li><li style=";text-align:right;direction:rtl"> הוסף 2 μl של ברצף מגיב transfection אל צינורות transfection דגירה 15 עד 20 דקות, כדי לאפשר מתחמי הטופס. ראה הטבלה של חומרים עבור מגיב transfection הספציפי כדי לשמש. </li><li style=";text-align:right;direction:rtl"> מוסיפים את תערובת transfection כולו מהצינור כל מיקרו-חכם ירידה לעמדות המקביל צלחות תרבית תאים. מערבולת בעדינות דגירה הצלחות במשך 48 שעות ב 37 מעלות צלזיוס עם 5% CO 2. </li><li style=";text-align:right;direction:rtl"> מדוד ייצור HIV-1 (סעיף 2), כדאיות התא (סעיף 3) והפעלה החיסונית (סעיף 4) ב צלחות תרבית תאים (איור 2 ג). </li></ol> 2. Assay הפקה ויראלי <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> הסר את צלחות תרבית תאי 24 גם מן החממה בעדינות מערבולת הצלחות בתוך תרבית תאי BSL3מכסה מנוע. עבר 150 μl של supernatant מכל טוב על תואמים היטב צלחת תחתית שטוחה 96-היטב, אשר תשמש לכמת ייצור HIV-1. הערה: מבחני כימות ויראלי נפוצות כוללות מדידת ביטוי של חלבון קפסיד HIV-1 (p24) על ידי assay immunosorbent enzyme-linked (ELISA) 20, לכימות רנ&quot;א נגיפי על ידי RT-PCR (RT-PCR) 21 ומדידת פעילות של האנזים RT HIV-1. צעדים 2.2 ל 2.5 להסביר שיטות לכמת HIV-1 RT פעילות 13,15,16. </li><li style=";text-align:right;direction:rtl"> העברה 5 μl של supernatant כדי מקביל בארות בצלחת 96-היטב, המכיל 25 μl של קוקטייל שיבוש ויראלי 15 (טבלה 1). דגירה את התערובת במשך 5 דקות ב RT ולהעביר את הצלחת לתחנת עבודת רדיואקטיביות. הערה: שלב 2.2. יש צורך רק אם לא זמינה עבודת רדיואקטיביות היא במעבדת BSL3. אם הצלחות לא צריכות תיוסרנהמעבדת BSL3, המשך לשלב 2.3. ולהוסיף 50 μl של קוקטייל שיבוש רדיואקטיביים / ויראלי (טבלה 1) במקום 25 μl של קוקטייל רדיואקטיבי. </li><li style=";text-align:right;direction:rtl"> כן רדיואקטיבי קוקטייל 15 (1 טבלה), ולהוסיף 25 μl היטב כל supernatant ויראלי קוקטייל הפרעה. דגירת הצלחות ב 37 מעלות צלזיוס למשך 2 שעות. </li><li style=";text-align:right;direction:rtl"> ספוט 5 μl של תערובת התגובה על ריבועים מקבילים סיבי זכוכית Di אתיל אמינו אתיל (DEAE) נייר filtermat ולאפשר הכתמים להתייבש במשך 10 דקות. ספוט את תערובת התגובה על כל ריבוע אחר כך ששתי אין דגימות ישירות דייר אחד אחרת. זה עוזר למנוע מעל הכלאה בין דגימות בעת קביעת ספירת לדקה (CPM) בשלב 2.6. </li><li style=";text-align:right;direction:rtl"> שטפו את העיתונים 5x במשך 5 דקות עם חיץ נתרן ציטרט מלוחים 2x (SSC) (טבלה 1), ואחריו שני שוטף 1 דקות עם אתנול 95%. אפשר בעיתונים להתייבש ולאטום אותם בשקיות מדגמות. </li><li style=";text-align:right;direction:rtl"> שיתוף שקיות מדגם קליפntaining נייר filtermat לתוך קלטת והכניס את הקלטת לתוך מונה נצנץ microplate. הגדר הדלפק לקרוא לדקה עבור 32 P עם התאריכים להשוואה סיפק עבור אצוות של [32 P] dTTP השתמשו בניסוי. בחר בו שימוש בדגימות לקרוא באמצעות מפת צלחת ולהתחיל הדלפק. </li><li style=";text-align:right;direction:rtl"> בכל שיטת כימות ויראלי, לחלק את הערכים שהתקבלו עבור כל RNA בדיקה על ידי הביקורת השלילית הסמוכה להכפיל ערך זה על ידי 100 כדי לקבל את עיכוב אחוז הייצור HIV-1 עבור כל לשכפל של RNAs הבדיקה. דוגמה לתוצאות השוואת RNAs מבדקים שונים בריכוזים שונים מסופק באיור 3. </li></ol> Assay כדאיות התא 3. <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> הסר את 96-גם הצלחות מן החממה ולהוסיף 20 μl של 5 מ&quot;ג / מ&quot;ל ​​MTT (3- [4.5-דימתיל-2-thiazolyl] -2,5-diphenyl-2H-tetrazolium ברומיד) מדולל בופר פוספט של Dulbecco ( DPBS) זה טוב. דגירת צלחות fאו 3 שעות ב 37 מעלות צלזיוס. </li><li style=";text-align:right;direction:rtl"> להוסיף 150 μl של isopropanol acidified עם חומר ניקוי (1% NP-40, 4 מ&quot;מ HCl ב isopropanol) זה טוב דגירה צלחות במשך שעה 2 ב RT. </li><li style=";text-align:right;direction:rtl"> קבע את הספיגה ב 570 ננומטר ב ספקטרופוטומטר microplate. </li><li style=";text-align:right;direction:rtl"> חשב את חילוף חומרי MTT ביחס לכל RNA מלא בדיקה חיובי על ידי חלוקת הערך המתקבל עבור כל דגימה על ידי שליטת transfection הסמוכה לה. דוגמא לתוצאות השוואת RNAs מבחן שונה כביקורת חיובית מסופקת באיור 4. </li></ol> 4. Assay ההפעלה החיסונית <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> הסר את 12 גם הצלחות מן החממה לשאוב את התקשורת והתרבות. לשטוף בעדינות את התאים פעמיים עם DPBS ולהוסיף 70 μl של חיץ תמוגה קר 22 (כולל מעכבי פרוטאז ו phosphatase, טבלה 1) זה טוב. דגירת הצלחות עבור 10 דקות על קרח. </li><li style=";text-align:right;direction:rtl"> עבר lysates תא צינורות המייקר ומהר להקפיא אותם על ידי טבילהצינורות בחנקן נוזלי. אפשר הדגימות להפשיר וחזרו על 2 יותר מחזור הפשרת הקפאה עבור סכום כולל של 3. </li><li style=";text-align:right;direction:rtl"> צנטריפוגה lysates במשך 15 דקות ב 4 ° C, 15,700 XG, כדי גלולה פסולת התא. מעבירים את supernatant צינורות מיקרו חדש ולקבוע את ריכוז החלבון באמצעות כחול Coomassie (ברדפורד) שיטה 23,24. </li><li style=";text-align:right;direction:rtl"> פתור 75 מיקרוגרם של חלבון מכל מדגם ב ג&#39;ל polyacrylamide denaturing 10% ולהעביר אל קרום nitrocellulose כפי שתואר לעיל 25,26. </li><li style=";text-align:right;direction:rtl"> בעקבות אלקטרופורזה ולהעביר קרום, לחשוף להקות חלבון על ידי דוגרי קרום Ponceau S (לוח 1) 1 דקות ואחריו כביסה במים מזוקקים פעמים. השתמש להקות סולם חלבון כמדריך לחתוך את הממברנה 80 ו -55 kDa. הערה: בשלב 4.4 דגימות ניתן להריץ על 16 x 18 ס&quot;מ 2 ג&#39;לים עד 34 kDa, כך שזה קל לחתוך את הקרום על העמדות שצוינו ולא לחתוך דרךלהקות של עניין. לחלופין, כמה ג&#39;לים ניתן להפיק דגימות אותו כדי למנוע חיתוך הממברנה. </li><li style=";text-align:right;direction:rtl"> יש לשטוף היטב את מכתים Ponceau S עם מי מלח שנאגרו טריס המכיל 0.05% Tween 20 (TBST, טבלה 1). להוסיף TBST עם 5% חלב דל שומן על מנת לכסות את הקרום לחלוטין. דגירה ממברנות ב RT עם תסיסה במשך שעה 1. </li><li style=";text-align:right;direction:rtl"> דגירה ממברנות O / N ב TBST עם אלבומין בסרום שור 3% (BSA) ונוגדנים מדולל ל -1 מכל 1,000 נגד ADAR1 (110 ו -150 KDA), phospho-PKR (62 KDA), ו phospho-IRF3 (47 KDA), עבור החלקים העליונים, אמצעיים ותחתונים של הממברנה, בהתאמה. </li><li style=";text-align:right;direction:rtl"> שטפו את ממברנות 5x במשך 5 דקות עם TBST ו דגירה ב TBST עם חלב 5% דל שומן ו נוגדנים משני נגד ארנב עז שכותרתו peroxidase (מדולל ל 1 ב 5000) במשך שעה 1. </li><li style=";text-align:right;direction:rtl"> שטוף את 5x ממברנות במשך 5 דקות עם TBST ולהחיל electrochemiluminescence פתרון (ECL) כדי להמחיש את הלהקות על סרטים על פי הוראות היצרן. </li><li style=";text-align:right;direction:rtl"> לאחר לדמיין את להקות חלבון על סרטים, לשטוף את החלקים באמצע ההר ובתחתית הממברנה במשך 10 דקות עם פתרון הפשטת נוגדן. הדגירה ממברנות O / N ב TBST עם 3% BSA ונוגדנים נגד PKR הכולל (ב 1 ב 500) ו IRF3 (ב -1 מכל 1,000), עבור באמצע והחתיכות תחתונות, בהתאמה. חזור על שלבים 4.8. ו -4.9. באמצעות העכבר אנטי-עז שכותרתו peroxidase במקום של נוגדנים משני נגד ארנב עבור קרום PKR (באמצע). </li><li style=";text-align:right;direction:rtl"> שטוף את הפיסה התחתונה של 5x הקרום למשך 5 דקות עם TBST ו דגירת הממברנה ב TBST עם BSA 3% במשך שעה 1 עם נוגדן נגד אקטין (מדולל ל 1 ב 5000). חזור על שלבים 4.8. ו -4.9. באמצעות עכבר אנטי-עז שכותרתו peroxidase במקום של נוגדנים משני נגד הארנב. דוגמא לתוצאות השוואת RNAs מבחן שונה כביקורת חיובית מסופקת באיור 5. ראה הטבלה של חומרים עבור הנוגדנים הספציפיים כדי לשמש. </li></ol>

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The authors have nothing to disclose.

את assay ייצור HIV-1 תיאר בוצעה באמצעות תאים HEK293T (איור 2), והוא דומה מבחני לשמש מסך HIV-1 RNA עבור ribozyme שנכנס לתוקף ב -13, shRNA 10,29, siRNA 30, ו U1i RNA 11,31 אתרי היעד. באמצעות שיטות שונות כדי לכמת ייצור HIV-1, רוב המחקרים מדדו ייצור ויראלי 48 שעות לאחר שיתוף transfecti...

הגבלה של טיפולי HIV-1 הנוכחיים היא שהם צריכים להתנהל באופן כרוני כדי למנוע התקדמות מחלה. להשתלות של HIV-1 עמיד לימפוציטים T, או תאי גזע hematopoietic, יש את הפוטנציאל לספק בקרה לטווח ארוך של שכפול HIV-1 בהעדר טיפול תרופתי 1,2 ויכול גם להיות גישה יעילה להשיג תרופה HIV-1 3. דרך אחת להפוך תאים עמידים שכפול HIV-1 היא להכניס גנים אחד או יותר קידוד עבור אנטי HIV-1 RNAs או פפטידים לתוך התאים של אדם שנדבק במהלך השתלה עצמית 4. כמה המועמד גנים אנטי HIV-1 עוצבו עם כמה ניסויים קליניים נכנסים שילובים של שני 5 או שלוש 6, כדי למנוע התפתחות של עמידות HIV-1 לכל גן יחיד. RNAs-1 נגד HIV הוא בין המועמדים הבולטים עבור ריפוי גנטי שילוב בשל הפוטנציאל הנמוך שלהם לעורר תגובה חיסונית ובגלל שהםמשועתק מתוך רצפי גנים מאוד קצרים. חלק RNAs נגד HIV-1 עוצב למקד כניסה ושילוב ויראלי. עם זאת, רוב RNAs נגד HIV-1 למקד צעדים שלאחר אינטגרציה במחזור החיים של הנגיף (איור 1). מעכבי פוסט אינטגרציה כוללים RNAs דמה, מיקוד חלבונים רגולטוריים HIV-1 טאט או Rev 1, ו RNAs מבוססי antisense, מיקוד אתרים שונים HIV-1 RNA, כגון ribozymes 7, shRNAs 8 ו U1i 9 RNAs. שיטות שנוצלו כדי להשוות את היעילות של RNAs נגד HIV-1 כוללות ניטור שכפולה נגיפית בתאי transduced עם גני מקודדי RNAs מועמד למדידת ייצור נגיפי בתאי transfected זמני עם פלסמידים להביע RNAs מועמד פלסמיד ביטוי HIV-1 10 -13. השתמשנו בעבר assay ייצור HIV-1 להקרין HIV-1 RNA עבור אתרי היעד ribozyme חדש 13-15. שיטות אלה שוכללו מאז כדי לייעל את הפורמט של RNAמולקולת פרעות הביעה מ- DNA פלסמיד כקובץ shRNA או נמסרה בתור siRNA סינטטי 16. את assay מודד את הייצור של וירוסים בוגרים מן הכליות עובריות אנושיים (HEK) תאי 293T, וניתן להשתמש בו כדי להשוות את ההשפעות של מעכבים כי למקד צעדים שלאחר אינטגרציה במחזור שהכפול HIV-1 (איור 1). עבור מעכבים כי למקד צעדים מראש אינטגרציה, מבחנים חלופיים כגון assay infectivity תא TZM-bl 17 נדרשים להעריך יעילות אנטי. חששות בטיחות סרן עבור המשלוח של אנטי HIV-1 RNAs במרפאת כוללים השפעות חוץ-היעד פוטנציאליות על RNAs אדם או חלבונים, והפעלה של חיישני חיסון מולדים. כדי להעריך את הרעילות של siRNAs נגד HIV-1, השתמשנו assay כדאיות התא שורות תאים שונות 16. כמו כן, אנו נמדדים הפעלה של החיישנים החיסוניים גדילי RNA הכפולים, R פרוטאין קינאז מופעל RNA (PKR) ו אגרה כמו 3 קולטן (TLR3), כמו גם לשעברpression של אינטרפרון מגורה גן, p150 ADAR1. מבחנים אלה יכולים לשמש כדי לאשר את היעילות של RNAs נגד HIV-1 הוא לא בשל השפעות עקיפות על כדאיויות תא או הפעלת חיישן חיסונית. הם גם שימושי למעט RNAs מועמד עם רעילות פוטנציאל להתפתח הלאה. ב הפרוטוקולים הבאים, נהלים לזהות RNAs הטיפולית חדשות ולבצע אופטימיזציה של הפורמט של התנחלויות קיימות מתואר. השיטות שימושיות מעכבי אינטגרציה שלאחר מבוסס RNA הקרנת שכפול HIV-1 יכולות להיות מותאמות למסך מעכבים שלאחר אינטגרציה אחרות, כגון מולקולות קטנות מיקוד יצוא Rev בתיווך של רנ&quot;א הנגיפי 18 או CRISPR / מערכות קאש שנועדו למקד משולבות HIV-1 DNA 19.

<table><tbody><tr><td>DMEM HyClone</td><td>GE Healthcare</td><td>SH30243.01</td><td></td></tr><tr><td>FBS HyClone</td><td>GE Healthcare</td><td>SH30396.03</td><td></td></tr><tr><td>Penicillin/Streptomycin Gibco</td><td>Thermo Fisher</td><td>15140-122</td><td></td></tr><tr><td>Cell culture plates, 96 well, 24 well, 6 well.</td><td>Corning</td><td>353075, 353047, 353043</td><td></td></tr><tr><td>Micro tubes Axygen</td><td>Corning</td><td>311-08-051</td><td></td></tr><tr><td>Low molecular weight Poly I:C</td><td>InvivoGen</td><td>3182-29-6</td><td></td></tr><tr><td>DharmaFECT-1</td><td>Dharmacon</td><td>T-2001-01</td><td>transfection reagent for synthetic RNAs</td></tr><tr><td>TransIT-LT1</td><td>Mirus</td><td>MIR 2300</td><td>transfection reagent for RNA expression plasmids</td></tr><tr><td>Nonidet P40 (NP-40)</td><td>USB</td><td>19628</td><td></td></tr><tr><td>[&lt;sup&gt;32&lt;/sup&gt;P]dTTP</td><td>Perkin Elmer</td><td>BLU505H</td><td></td></tr><tr><td>poly(A) RNA template&amp;nbsp;</td><td>Sigma-Aldrich</td><td>10108626001</td><td></td></tr><tr><td>oligo(dT)&lt;sub&gt;12-18&lt;/sub&gt; DNA primer</td><td>Thermo Fisher</td><td>18418-012</td><td></td></tr><tr><td>DEAE filtermat paper&amp;nbsp;</td><td>Perkin Elmer</td><td>1450-522</td><td></td></tr><tr><td>Microplate scintillation counter</td><td>Perkin Elmer</td><td>1450-024</td><td></td></tr><tr><td>MTT</td><td>Sigma-Aldrich</td><td>M-2128</td><td></td></tr><tr><td>DPBS HyClone</td><td>GE Healthcare</td><td>SH30028.02</td><td></td></tr><tr><td>Microplate spectrophotometer</td><td>Bio-rad</td><td>1706930</td><td></td></tr><tr><td>Lysis buffer tablets</td><td>Roche</td><td>4693159001, 4906837001</td><td>protease and phosphatase inhibitors</td></tr><tr><td>Microcentrifuge</td><td>Eppendorf</td><td>5415R</td><td></td></tr><tr><td>Bradford reagent</td><td>Bio-rad</td><td>500-0006</td><td></td></tr><tr><td>Gel running chamber</td><td>Hoefer</td><td>SE600</td><td></td></tr><tr><td>Semi-dry transfer cell</td><td>Bio-rad</td><td>1703940</td><td></td></tr><tr><td>Protein ladder EZ-Run</td><td>Thermo Fisher</td><td>BP3603-500</td><td></td></tr><tr><td>Nitrocellulose membrane</td><td>Bio-rad</td><td>162-0094</td><td></td></tr><tr><td>BSA</td><td>Sigma-Aldrich</td><td>A9647-1006</td><td></td></tr><tr><td>Antibody stripping solution</td><td>Millipore</td><td>2504</td><td></td></tr><tr><td>ECL - Pierce</td><td>Thermo Fisher&amp;nbsp;</td><td>PI32106</td><td></td></tr><tr><td>ADAR1 antibody</td><td></td><td></td><td>from Dr. B.L. Bass</td></tr><tr><td>phospho-T446-PKR antibody</td><td>Abcam</td><td>ab32036</td><td></td></tr><tr><td>phospho-S396-IRF3 antibody</td><td>Cell Signaling</td><td>4947</td><td></td></tr><tr><td>PKR antibody</td><td></td><td></td><td>from Dr. A. Hovanessian</td></tr><tr><td>IRF3 antibody</td><td>Cell Signaling</td><td>11904</td><td></td></tr><tr><td>Actin antibody</td><td>Millipore</td><td>MAB1501</td><td></td></tr><tr><td>Peroxidase-labeled goat anti-rabbit</td><td>KPL</td><td>474-1506</td><td></td></tr><tr><td>Peroxidase-labeled goat anti-mouse</td><td>KPL</td><td>474-1806</td><td></td></tr><tr><td>Ponceau S&amp;nbsp;</td><td>Sigma-Aldrich</td><td>6226-79-5</td><td></td></tr></tbody></table>

evaluation of the efficacy and toxicity of rnas targeting hiv-1 production for use in gene or drug therapy

Small RNA therapies targeting post-integration steps in the HIV-1 replication cycle are among the top candidates for gene therapy and have the potential to be used as drug therapies for HIV-1 infection. Post-integration inhibitors include ribozymes, short hairpin (sh) RNAs, small interfering (si) RNAs, U1 interference (U1i) RNAs and RNA aptamers. Many of these have been identified using transient co-transfection assays with an HIV-1 expression plasmid and some have advanced to clinical trials. In addition to measures of efficacy, small RNAs have been evaluated for their potential to affect the expression of human RNAs, alter cell growth and/or differentiation, and elicit innate immune responses. In the protocols described here, a set of transient transfection assays designed to evaluate the efficacy and toxicity of RNA molecules targeting post-integration steps in the HIV-1 replication cycle are described. We have used these assays to identify new ribozymes and optimize the format of shRNAs and siRNAs targeting HIV-1 RNA. The methods provide a quick set of assays that are useful for screening new anti-HIV-1 RNAs and could be adapted to screen other post-integration inhibitors of HIV-1 replication.

סכימטי הכללי של הנהלים מוצג באיור 2 עם תכנית transfection לדוגמה עבור שלושה RNAs ניסיוניים RNA מלא מסופק באיור 2B. עבור מבחני כדאיות התא ייצור ויראליות, מחוץ לקרוא לכל מבנה המבחן מנורמל כביקורת שלילית. משכפל הם transfected בסטים, כך שכל RNA המבחן מנו...

Watch this Scientific Journal Video about Evaluation of the Efficacy And Toxicity of RNAs Targeting HIV-1 Production for Use in Gene or Drug Therapy at JoVE.com

Evaluation of the Efficacy And Toxicity of RNAs Targeting HIV-1 Production for Use in Gene or Drug Therapy

Methods to evaluate the efficacy and toxicity of RNA molecules targeting post-integration steps of the HIV-1 replication cycle are described. These methods are useful for screening new molecules and optimizing the format of existing ones.

הערכת היעילות והרעילות של RNAs מיקוד ייצור HIV-1 לשימוש ב ג&#39;ין או טיפול תרופתי

Small RNA therapies targeting post-integration steps in the HIV-1 replication cycle are among the top candidates for gene therapy and have the potential ...

evaluation-efficacy-toxicity-rnas-targeting-hiv-1-production-for-use

Research

JoVE Journal

Immunology and Infection

7.8K Views.  Lady Davis Institute for Medical Research. Methods to evaluate the efficacy and toxicity of RNA molecules targeting post-integration steps of the HIV-1 replication cycle are described. These methods are useful for screening new molecules and optimizing the format of existing ones. 

Video: Evaluation of the Efficacy And Toxicity of RNAs Targeting HIV-1 Production for Use in Gene or Drug Therapy

Genome-wide RNAi Screening to Identify Host Factors That Modulate Oncolytic Virus Therapy

High-throughput genome-wide RNAi (RNA interference) screening technology has been widely used for discovering host factors that impact&#160;virus replication. Here we present the application of this technology to uncovering host targets that specifically modulate the replication of Maraba virus, an oncolytic rhabdovirus, and vaccinia virus with the goal of enhancing therapy. While the protocol has been tested for use with oncolytic Maraba virus and oncolytic vaccinia virus, this approach is applicable to other oncolytic viruses and can also be utilized for identifying host targets that modulate virus replication in mammalian cells in general. This protocol describes the development and validation of an assay for high-throughput RNAi screening in mammalian cells, the key considerations and preparation steps important for conducting a primary high-throughput RNAi screen, and a step-by-step guide for conducting a primary high-throughput RNAi screen; in addition, it broadly outlines the methods for conducting secondary screen validation and tertiary validation studies. The benefit of high-throughput RNAi screening is that it allows one to catalogue, in an extensive and unbiased fashion, host factors that modulate any aspect of virus replication for which one can develop an in vitro assay such as infectivity, burst size, and cytotoxicity. It has the power to uncover biotherapeutic targets unforeseen based on current knowledge.

Here we describe a protocol for employing high-throughput RNAi screening to uncover host targets that can be manipulated to enhance oncolytic virus therapy, specifically rhabodvirus and vaccinia virus therapy, but it can be readily adapted to other oncolytic virus platforms or for discovering host genes that modulate virus replication generally.

ברמת הגנום RNAi ההקרנה כדי לזהות גורמים מארח לווסת את הטיפול Oncolytic וירוס

High-throughput genome-wide RNAi (RNA interference) screening technology has been widely used for discovering host factors that impact&#160;virus ...

Cancer Research

Development of Cell-type specific anti-HIV gp120 aptamers for siRNA delivery

The global epidemic of infection by HIV has created an urgent need for new classes of antiretroviral agents. The potent ability of small interfering (si)RNAs to inhibit the expression of complementary RNA transcripts is being exploited as a new class of therapeutics for a variety of diseases including HIV. Many previous reports have shown that novel RNAi-based anti-HIV/AIDS therapeutic strategies have considerable promise; however, a key obstacle to the successful therapeutic application and clinical translation of siRNAs is efficient delivery. Particularly, considering the safety and efficacy of RNAi-based therapeutics, it is highly desirable to develop a targeted intracellular siRNA delivery approach to specific cell populations or tissues. The HIV-1 gp120 protein, a glycoprotein envelope on the surface of HIV-1, plays an important role in viral entry into CD4 cells. The interaction of gp120 and CD4 that triggers HIV-1 entry and initiates cell fusion has been validated as a clinically relevant anti-viral strategy for drug discovery. 
Herein, we firstly discuss the selection and identification of 2'-F modified anti-HIV gp120 RNA aptamers. Using a conventional nitrocellulose filter SELEX method, several new aptamers with nanomolar affinity were isolated from a 50 random nt RNA library. In order to successfully obtain bound species with higher affinity, the selection stringency is carefully controlled by adjusting the conditions. The selected aptamers can specifically bind and be rapidly internalized into cells expressing the HIV-1 envelope protein. Additionally, the aptamers alone can neutralize HIV-1 infectivity. Based upon the best aptamer A-1, we also create a novel dual inhibitory function anti-gp120 aptamer-siRNA chimera in which both the aptamer and the siRNA portions have potent anti-HIV activities. Further, we utilize the gp120 aptamer-siRNA chimeras for cell-type specific delivery of the siRNA into HIV-1 infected cells. This dual function chimera shows considerable potential for combining various nucleic acid therapeutic agents (aptamer and siRNA) in suppressing HIV-1 infection, making the aptamer-siRNA chimeras attractive therapeutic candidates for patients failing highly active antiretroviral therapy (HAART).

Several 2&#x2019;-Fluoro RNA aptamers against HIV-1Ba-L gp120 with nanomole affinity are isolated from a RNA library by in vitro SELEX procedure. A new dual inhibitory function anti-gp120 aptamer-siRNA chimera is created and shows considerable promise for systemic anti-HIV therapy.

פיתוח נייד מסוג ספציפי נגד HIV gp120 aptamers למסירה siRNA

The global epidemic of infection by HIV has created an urgent need for new classes of antiretroviral agents. The potent ability of small interfering ...

DNA Vector-based RNA Interference to Study Gene Function in Cancer

RNA interference (RNAi) inhibits gene expression by specifically degrading target mRNAs. Since the discovery of double-stranded small interference RNA (siRNA) in gene silencing1, RNAi has become a powerful research tool in gene function studies. Compared to genetic deletion, RNAi-mediated gene silencing possesses many advantages, such as the ease with which it is carried out and its suitability to most cell lines. Multiple studies have demonstrated the applications of RNAi technology in cancer research. In particular, the development of the DNA vector-based technology to produce small hairpin RNA (shRNA) driven by the U6 or H1 promoter has made long term and inducible gene silencing possible2,3. Its use in combination with genetically engineered viral vectors, such as lentivirus, facilitates high efficiencies of shRNA delivery and/or integration into genomic DNA for stable shRNA expression. 
We describe a detailed procedure using the DNA vector-based RNAi technology to determine gene function, including construction of lentiviral vectors expressing shRNA, lentivirus production and cell infection, and functional studies using a mouse xenograft model. 
Various strategies have been reported in generating shRNA constructs. The protocol described here employing PCR amplification and a 3-fragment ligation can be used to directly and efficiently generate shRNA-containing lentiviral constructs without leaving any extra nucleotide adjacent to a shRNA coding sequence. Since the shRNA-expression cassettes created by this strategy can be cut out by restriction enzymes, they can be easily moved to other vectors with different fluorescent or antibiotic markers. Most commercial transfection reagents can be used in lentivirus production. However, in this report, we provide an economic method using calcium phosphate precipitation that can achieve over 90% transfection efficiency in 293T cells. Compared to constitutive shRNA expression vectors, an inducible shRNA system is particularly suitable to knocking down a gene essential to cell proliferation. We demonstrate the gene silencing of Yin Yang 1 (YY1), a potential oncogene in breast cancer4,5, by a Tet-On inducible shRNA system and its effects on tumor formation. Research using lentivirus requires review and approval of a biosafety protocol by the Biosafety Committee of a researcher's institution. Research using animal models requires review and approval of an animal protocol by the Animal Care and Use Committee (ACUC) of a researcher's institution.

RNA interference (RNAi) possesses many advantages over gene knockout and has been broadly used as a tool in gene functional studies. The invention of DNA vector-based RNAi technology has made long term and inducible gene knockdown possible, and also increased the feasibility of gene silencing in vivo.

וקטור מבוסס DNA התערבות RNA ללמוד לתפקד גנים סרטן

RNA interference (RNAi) inhibits gene expression by specifically degrading target mRNAs. Since the discovery of double-stranded small interference RNA ...

Medicine

High-throughput Screening for Broad-spectrum Chemical Inhibitors of RNA Viruses

RNA viruses are responsible for major human diseases such as flu, bronchitis, dengue, Hepatitis C or measles. They also represent an emerging threat because of increased worldwide exchanges and human populations penetrating more and more natural ecosystems. A good example of such an emerging situation is chikungunya virus epidemics of 2005-2006 in the Indian Ocean. Recent progresses in our understanding of cellular pathways controlling viral replication suggest that compounds targeting host cell functions, rather than the virus itself, could inhibit a large panel of RNA viruses. Some broad-spectrum antiviral compounds have been identified with host target-oriented assays. However, measuring the inhibition of viral replication in cell cultures using reduction of cytopathic effects as a readout still represents a paramount screening strategy. Such functional screens have been greatly improved by the development of recombinant viruses expressing reporter enzymes capable of bioluminescence such as luciferase. In the present report, we detail a high-throughput screening pipeline, which combines recombinant measles and chikungunya viruses with cellular viability assays, to identify compounds with a broad-spectrum antiviral profile.

In vitro assays to measure virus replication have been greatly improved by the development of recombinant RNA viruses expressing luciferase or other enzymes capable of bioluminescence. Here we detail a high-throughput screening pipeline that combines such recombinant strains of measles and chikungunya viruses to isolate broad-spectrum antivirals from chemical libraries.

הקרנת תפוקה גבוהה לספקטרום רחב כימיים מעכבי RNA וירוסים

RNA viruses are responsible for major human diseases such as flu, bronchitis, dengue, Hepatitis C or measles. They also represent an emerging threat ...

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors

Although a number of anti HIV drugs have been approved, there are still problems with toxicity and drug resistance. This demonstrates a need to identify new compounds that can inhibit infection by the common drug resistant HIV-1 strains with minimal toxicity. Here we describe an efficient assay that can be used to rapidly determine the cellular cytotoxicity and efficacy of a compound against WT and mutant viral strains.
The desired target cell line is seeded in a 96-well plate and, after a 24 hr incubation, serially dilutions of the compounds to be tested are added. No further manipulations are necessary for cellular cytotoxicity assays; for anti HIV assays a predetermined amount of either a WT or drug resistant HIV-1 vector that expresses luciferase is added to the cells. Cytotoxicity is measured by using an ATP dependent luminescence assay and the impact of the compounds on infectivity is measured by determining the amount of luciferase in the presence or the absence of the putative inhibitors.
This screening assay takes 4 days to complete and multiple compounds can be screened in parallel. Compounds are screened in triplicate and the data are normalized to the infectivity/ATP levels in absence of target compounds. This technique provides a quick and accurate measurement of the efficacy and toxicity of potential anti HIV compounds.

Here we describe cellular cytotoxicity and single round infectivity assays that allow for the rapid and accurate screening of compounds to determine their cellular cytotoxicity (CC50) and IC50 values against WT and drug resistant HIV-1.

הקרנה מהירה של HIV ההפוך טרנסקריפטאז וintegrase המעכבים

Although a number of anti HIV drugs have been approved, there are still problems with toxicity and drug resistance. This demonstrates a need to identify ...

Bacterial Delivery of RNAi Effectors: Transkingdom RNAi

RNA interference (RNAi) represents a high effective mechanism for specific inhibition of mRNA expression. Besides its potential as a powerful laboratory tool, the RNAi pathway appears to be promising for therapeutic utilization. For development of RNA interference (RNAi)-based therapies, delivery of RNAi-mediating agents to target cells is one of the major obstacles. A novel strategy to overcome this hurdle is transkingdom RNAi (tkRNAi). This technology uses non-pathogenic bacteria, e.g. Escherichia coli, to produce and deliver therapeutic short hairpin RNA (shRNA) into target cells to induce RNAi. A first-generation tkRNAi-mediating vector, TRIP, contains the bacteriophage T7 promoter for expression regulation of a therapeutic shRNA of interest. Furthermore, TRIP has the Inv locus from Yersinia pseudotuberculosis that encodes invasin, which permits natural noninvasive bacteria to enter &beta;1-integrin-positive mammalian cells and the HlyA gene from Listeria monocytogenes, which produces listeriolysin O. This enzyme allows the therapeutic shRNA to escape from entry vesicles within the cytoplasm of the target cell. TRIP constructs are introduced into a competent non-pathogenic Escherichia coli strain, which encodes T7 RNA polymerase necessary for the T7 promoter-driven synthesis of shRNAs. A well-characterized cancer-associated target molecule for different RNAi strategies is ABCB1 (MDR1/P-glycoprotein, MDR1/P-gp). This ABC-transporter acts as a drug extrusion pump and mediates the "classical" ABCB1-mediated multidrug resistance (MDR) phenotype of human cancer cells which is characterized by a specific cross resistance pattern. Different ABCB1-expressing MDR cancer cells were treated with anti-ABCB1 shRNA expression vector bearing E. coli. This procedure resulted in activation of the RNAi pathways within the cancer cells and a considerable down regulation of the ABCB1 encoding mRNA as well as the corresponding drug extrusion pump. Accordingly, drug accumulation was enhanced in the pristine drug-resistant cancer cells and the MDR phenotype was reversed. By means of this model the data provide the proof-of-concept that tkRNAi is suitable for modulation of cancer-associated factors, e.g. ABCB1, in human cancer cells.

For development of RNA interference (RNAi)-based therapies, a novel strategy was developed, transkingdom RNAi (tkRNAi). This technology uses non-pathogenic bacteria to produce and deliver therapeutic short hairpin RNA (shRNA) into target cells. Here, tkRNAi was successfully applied for reversal of classical ABCB1-mediated multidrug resistance (MDR) of cancer cells.

משלוח חיידקית של RNAi effectors: Transkingdom RNAi

RNA interference (RNAi) represents a high effective mechanism for specific inhibition of mRNA expression. Besides its potential as a powerful laboratory ...

Biology

MicroRNA-based Regulation of Picornavirus Tropism

Cell-specific restriction of viral replication without concomitant attenuation can benefit vaccine development, gene therapy, oncolytic virotherapy, and understanding the biological properties of viruses. There are several mechanisms for regulating viral tropism, however they tend to be virus class specific and many result in virus attenuation. Additionally, many viruses, including picornaviruses, exhibit size constraints that do not allow for incorporation of large amounts of foreign genetic material required for some targeting methods. MicroRNAs are short, non-coding RNAs that regulate gene expression in eukaryotic cells by binding complementary target sequences in messenger RNAs, preventing their translation or accelerating their degradation. Different cells exhibit distinct microRNA signatures and many microRNAs serve as biomarkers. These differential expression patterns can be exploited for restricting gene expression in cells that express specific microRNAs while maintaining expression in cells that do not. In regards to regulating viral tropism, sequences complementary to specific microRNAs are incorporated into the viral genome, generally in the 3' non-coding regions, targeting them for destruction in the presence of the cognate microRNAs thus preventing viral gene expression and/or replication. MicroRNA-targeting is a technique that theoretically can be applied to all viral vectors without altering the potency of the virus in the absence of the corresponding microRNAs. Here we describe experimental methods associated with generating a microRNA-targeted picornavirus and evaluating the efficacy and specificity of that targeting in vitro. This protocol is designed for a rapidly replicating virus with a lytic replication cycle, however, modification of the time points analyzed and the specific virus titration readouts used will aid in the adaptation of this protocol to many different viruses.

We describe here a method for regulating picornavirus tropism by incorporating sequences complementary to specific microRNAs into the viral genome. This protocol can be adapted to all different classes of viruses with modifications based upon the length and nature of their life cycle.

תקנה מבוססת MicroRNA של Picornavirus כמיהות

Cell-specific restriction of viral replication without concomitant attenuation can benefit vaccine development, gene therapy, oncolytic virotherapy, and ...

High Throughput In Vitro Assessment of Latency Reversing Agents on HIV Transcription and Splicing

HIV remains incurable due to the existence of a reservoir of cells that harbors stable and latent form of the virus, which stays invisible to the immune system and is not targeted by the current antiretroviral therapy (cART). Transcription and splicing have been shown to reinforce HIV-1 latency in resting CD4+ T cells. Reversal of latency by the use of latency reversal agents (LRAs) in the &#34;shock and kill&#34; approach has been studied extensively in an attempt to purge this reservoir but has thus far not shown any success in clinical trials due to the lack of development of adequate small molecules that can efficiently perturb this reservoir. The protocol presented here provides a method for reliably and efficiently assessing latency reversal agents (LRAs) on HIV transcription and splicing. This approach is based on the use of an LTR-driven dual color reporter that can simultaneously measure the effect of an LRA on transcription and splicing by flow cytometry. The protocol described here is adequate for adherent cells as well as the cells in suspension. It is useful for testing a large number of drugs in a high throughput system. The method is technically simple to implement and cost-effective. In addition, the use of flow cytometry allows the assessment of cell viability and thus drug toxicity at the same time.

A high throughput protocol for functional assessment of HIV efficient reactivation and clearance of latent proviruses is described and applied by testing the impact of interventions on HIV transcription and splicing. Representative results of the effect of latency reversing agents on LTR-driven transcription and splicing are provided.

תפוקה גבוהה בחוץ גופית הערכה של השהיה היפוך סוכנים על HIV שעתוק ו שחבור

HIV remains incurable due to the existence of a reservoir of cells that harbors stable and latent form of the virus, which stays invisible to the immune ...

Detection of Viral RNA by Fluorescence in situ Hybridization (FISH)

Viruses that infect cells elicit specific changes to normal cell functions which serve to divert energy and resources for viral replication. Many aspects of host cell function are commandeered by viruses, usually by the expression of viral gene products that recruit host cell proteins and machineries. Moreover, viruses engineer specific membrane organelles or tag on to mobile vesicles and motor proteins to target regions of the cell (during de novo infection, viruses co-opt molecular motor proteins to target the nucleus; later, during virus assembly, they will hijack cellular machineries that will help in the assembly of viruses). Less is understood on how viruses, in particular those with RNA genomes, coordinate the intracellular trafficking of both protein and RNA components and how they achieve assembly of infectious particles at specific loci in the cell. The study of RNA localization began in earlier work. Developing lower eukaryotic embryos and neuronal cells provided important biological information, and also underscored the importance of RNA localization in the programming of gene expression cascades. The study in other organisms and cell systems has yielded similar important information. Viruses are obligate parasites and must utilise their host cells to replicate. Thus, it is critical to understand how RNA viruses direct their RNA genomes from the nucleus, through the nuclear pore, through the cytoplasm and on to one of its final destinations, into progeny virus particles 1.
FISH serves as a useful tool to identify changes in steady-state localization of viral RNA. When combined with immunofluorescence (IF) analysis 22, FISH/IF co-analyses will provide information on the co-localization of proteins with the viral RNA3. This analysis therefore provides a good starting point to test for RNA-protein interactions by other biochemical or biophysical tests 4,5, since co-localization by itself is not enough evidence to be certain of an interaction. In studying viral RNA localization using a method like this, abundant information has been gained on both viral and cellular RNA trafficking events 6. For instance, HIV-1 produces RNA in the nucleus of infected cells but the RNA is only translated in the cytoplasm. When one key viral protein is missing (Rev) 7, FISH of the viral RNA has revealed that the block to viral replication is due to the retention of the HIV-1 genomic RNA in the nucleus 8. 
Here, we present the method for visual analysis of viral genomic RNA in situ. The method makes use of a labelled RNA probe. This probe is designed to be complementary to the viral genomic RNA. During the in vitro synthesis of the antisense RNA probe, the ribonucleotide that is modified with digoxigenin (DIG) is included in an in vitro transcription reaction. Once the probe has hybridized to the target mRNA in cells, subsequent antibody labelling steps (Figure 1) will reveal the localization of the mRNA as well as proteins of interest when performing FISH/IF.

Detection of Viral RNA by Fluorescence in situ Hybridization FISH

A fluorescence in situ hybridization (FISH) method was developed to visually detect viral genomic RNA using fluorescence microscopy. A probe is made with specificity to the viral RNA that can then be identified using a combination of hybridization and immunofluorescence techniques. This technique offers the advantage of identifying the localization of the viral RNA or DNA at steady-state, providing information on the control of intracellular virus trafficking events.

זיהוי של רנ&quot;א נגיפי על ידי הקרינה<em&gt; באתרו</em&gt; הכלאה (דגים)

Viruses  that infect cells elicit specific changes to normal cell functions which serve  to divert energy and resources for viral replication. Many ...

Oral Combinational Antiretroviral Treatment in HIV-1 Infected Humanized Mice

The human immunodeficiency virus (HIV-1) pandemic continues to spread unabated worldwide, and currently, there is no vaccine available against HIV. Although combinational antiretroviral therapy (cART) has been successful in suppressing viral replication, it cannot completely eradicate the reservoir from HIV-infected individuals. A safe and effective cure strategy for HIV infection will require multipronged methods, and therefore the advancements of animal models for HIV-1 infection are pivotal for the development of HIV cure research. Humanized mice recapitulate key features of HIV-1 infection. The humanized mouse model can be infected by HIV-1 and viral replication can be controlled with cART regimens. Moreover, cART interruption results in a prompt viral rebound in humanized mice. However, administration of cART to the animal can be ineffective, difficult, or toxic, and many clinically relevant cART regimens are unable to be optimally utilized. Along with being potentially unsafe for researchers, administration of cART by a commonly used intensive daily injection procedure induces stress by physical restraint of the animal. The novel oral cART method to treat HIV-1 infected humanized mice described in this article resulted in suppression of viremia below the detection level, increased rate of CD4+ restoration, and improved overall health in HIV-1 infected humanized mice.

This protocol describes a novel method to deliver oral combinational antiretroviral drugs that successfully suppress HIV-1 RNA replication in humanized mice.

טיפול אנטי-רטרו-ויראלי משולב דרך הפה בעכברים נגועים ב- HIV-1

The human immunodeficiency virus (HIV-1) pandemic continues to spread unabated worldwide, and currently, there is no vaccine available against HIV. ...

הערכת היעילות והרעילות של RNAs מיקוד ייצור HIV-1 לשימוש ב ג'ין או טיפול תרופתי

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