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小鼠被饲养并安置在弗朗西斯·克里克研究所(Francis Crick Institute)的特定无病原体设施中。所有用于育种和实验的方案均经项目许可证P4D8F6075批准 ,并根据1986年的《动物科学程序法》进行 。
所有DNA构建体均使用大肠杆菌DH5A(Thermo Fisher Scientific)生产,并使用Qiagen的质粒MIDIPREP试剂盒提取。这项研究中使用的质粒为:RFP-GAL-350,LAMP1-RFP(Addgene ,1817)和G3BP1-MEGFP(Addgene,135997)。
KOLF2人类诱导的多能干(IPS细胞来自英格兰公共卫生培养收藏(目录编号77650100) 。MEGFPPPPPPPPPPPPPP-G3BP1人IPS细胞(用于CLEM研究)来自Coriell Institute(Catalog Number AICS AICS-0082 Cl.1)。Fisher科学在接收时通过str谱图进行了验证,并通过使用Versene(Gibco)进行了3个单核工厂,以70%的汇合(在先前报告的IPS悬架)中 ,用PCR进行了70%的汇合。在E8加10 µM Y-27632(干细胞技术)中,并将其播种成800个板块(干胶技术),每个孔中有4×106个细胞 ,并在100G处离心3分钟,每天用两种50%培养基喂食,并用E8补充了50 ng ML-1人类BMML-1 pepRREN(PEP MMPR)。(peprotech)和20 ng ml-1人类SCF(peprotech)在第4天 ,通过轻柔的移液中的井中收集胚胎,并通过倒置的40 µM细胞滤网中的胚胎浮游物 。X-VIVO15(LONZA)补充了谷氨酸(Gibco),50 µMβ-甲醇(Gibco) ,100 ng ML-1 HM-CSF(Peprotech)和25 ng ML-1。这些单核细胞工厂每周用工厂培养基喂食5周,直到在上清液中观察到大量的单核细胞为止。每周收集多达50%的上清液,并用10-20 mL工厂培养基喂养工厂 。将上清液以300克离心5分钟 ,并将细胞重悬于补充的X-Vivo15中,并补充了谷氨酸和100 ng ml-1人M-CSF,并以每10 cm Petri菜肴的4×106细胞镀以在7天的时间内分开。在第4天,进行了50%的中等变化。为了脱离细胞 ,将IPSDM板用PBS洗涤一次,然后在37°C和5%CO2中与Versene孵育15分钟,然后用PBS稀释1:3并轻轻刮擦 。将巨噬细胞以300G离心 ,并在X-Vivo15中进行实验。
使用标准条件培养U2OS和HELA细胞。两种细胞系都保持在补充10%胎牛血清(FBS)的Dulbecco改良的Eagle培养基(DMEM)中 。将细胞在含5%CO2的加湿气氛中在37°C下孵育。U2OS野生型和G3BP1/2 KO U2OS细胞系来自P. Anderson37的实验室。细胞对支原体污染(由PCR检查)为阴性 。
使用霓虹灯系统(Invitrogen)将质粒DNA电穿孔到IPSDM中。将IPSDM以1.5×106细胞重悬于100 µL缓冲液R中。将每1 µg质粒DNA混合物每1微透明液重悬于霓虹灯移液管中,并在1,500 V中在1,500 V中电穿孔,持续30毫秒 ,持续30毫秒。然后将细胞铺在视板玻璃底部96井板(6005430,Perkinelmer)中,用于高内含物分析或用于共焦成像研究的IBIDI µ-SLIDE 18孔玻璃底盖(81817) 。
用PBS洗涤IPSDM两次 ,并使用LONZA 2B 2B核对象(核对象2B设备,AAB-1001)在适当的初级核反理溶液(AMAXATM人单核细胞核对象试剂盒,VPA-1007)中进行电穿孔。每次反应使用500万个IPSDM ,并将其重悬于100 µL的原核离子溶液中,其中含有4 µg的链球菌(SPCAS9)(IDT)与总计12 µg靶向合成化学修饰的单个指南RNA(SGRNA(SGRNA)(Synthego)(Synthego)(Synthego)(Synthego)(替代)(替代))(IDT)。然后,使用靶向G3BP1基因的两个SGRNA和两个靶向基因G3BP2的SGRNA和使用Y001程序的Cas9 -RNP混合物核定IPSDM 。在35毫米菌素培养皿盘板(121 V,Thermo Scientific)中 ,在预热的X-Vivo15中培养细胞的细胞。在核反射后2小时,将100 ng ml-1人类M-CSF添加到细胞中。将培养皿与5%CO2孵育的37°C孵化器中孵育 。3天后,添加了等同体积的新鲜培养基 ,包括100 ng ml-1人类M-CSF。最初分离后六天,将分化的巨噬细胞分离在Versene中,并在X-Vivo15中进行实验。
使用的SGRNA为:g3bp2_g1:cgccctacaagcagcggact;g3bp2_g2:aagctccggaatatttacac;G3BP1_G1:CGCCCCGACCAGGGGGGACT;和G3BP1_G2:Aggcccccagacatgctgcat 。
在补充10%FBS的Dulbecco改良的Eagle培养基(DMEM)中培养HeLa细胞。对于短的干扰RNA(siRNA)转染 ,将靶向G3BP1和G3BP2的SmartPool SiRNA(从Dharmacon获得)在Opti-Mem培养基中稀释,并将DHARMAFECT转染试剂与siRNA混合,以达到最终浓度25 nm。在室温下将siRNA转染复合物孵育5-10分钟 。将HeLa细胞以密度铺板 ,在转染时允许50–70%的汇合度。然后将siRNA转染复合物添加到镀以6个井板中的细胞(1.5 mL最终体积),然后再孵育24小时,然后再重复相同的方案进行额外的一天(两轮转染)。24小时后 ,收集细胞进行随后的实验。作为对照siRNA,使用相同的方案使用了消音器选择2 siRNA(4390846,Thermo Fischer)的阴性对照 。
靶向siRNA如下:
targetplus smartpool sirna j-012099-06,g3bp1目标序列guggugguggugcgcauua;targetplus smartpool sirna j-012099-07 ,g3bp1目标序列agacauagcucucagacagagua;targetplus smartpool sirna j-012099-08,g3bp1目标序列gaaggcgaccgacgagaua;targetplus smartpool sirna j-012099-09,g3bp1目标序列gcgagaacaacgaauaaa;targetplus smartpool sirna j-015329-09 ,g3bp2目标序列ugaauaaaaagcuccggaaua;targetplus smartpool sirna j-015329-10,g3bp2目标序列gaauuuaaagucugggggaggaga;targetplus smartpool sirna j-015329-11,g3bp2目标序列acaacgaccuagagaacga;targetplus smartpool sirna j-015329-12 ,g3bp2目标序列:gcguauggucuugacuaua。
从英国国家卫生局血液和移植服务中通过ficoll-paque Premium(GE Healthcare 17-5442-03)离心60分钟,以300g的速度分离出白血细胞(NC24)(NC24)。用MAC冲洗溶液(Miltenyi 130-091-222)将单核细胞洗涤两次,以去除血小板 ,然后在室温下以10 ml RBC裂解缓冲液(Sigma R7757)在室温下孵育剩余的红细胞,每颗3分钟 。用冲洗缓冲液洗涤细胞并再次颗粒,然后重悬于80 µL MAC冲洗溶液中 ,补充了1%BSA(MACS/BSA)和20 µL抗CD14磁珠(MILTENYI 130-050-201),每108个细胞,并在冰上孵育20分钟。然后,通过离心在MAC/BSA中洗涤细胞 ,在每108个细胞中重悬于500 µL MAC/BSA中,并在四元素分离剂磁铁(Miltenyi 130-090-976)的领域中通过LS柱(Miltenyi 130-042-401)。用MAC/BSA洗涤该色谱柱,然后将积极选择的细胞洗脱 ,离心并重悬于RPMI 1640中,用谷氨酸和HEPE(Gibco 72400- 02),10%热激活的FBS和50 ng Ml-1 HM-1 HM-CSF(perdrotech)对106个细胞的浓度为106细胞 ,将其浓缩为106细胞 。将它们放置在与5%CO2的加湿的37°C孵化器中,其中3天后添加了同样的新鲜培养基。最初分离后六天,将分化的巨噬细胞分离在0.5 mm EDTA中 ,在冰冷的PBS和5×105个细胞中,每孔的12孔板播种,用于蛋白质印迹实验。
D. Young和S. H. Wilson提供了野生型MTB H37RV和MTBH37RVΔRD1 。如先前报道的51 ,生成荧光MTB菌株。E2-Crimson MTB是通过使用PTEC19转化(Addgene 30178,由L. ramakrishnan沉积的)生成的。通过测序验证菌株,并通过MTB培养物的脂质提取物的薄层色谱法测试了邻苯酚二聚糖的阳性 。MTB菌株在补充有0.2%甘油,0.05%Tween-80和10%白蛋白右旋糖氧酶(ADC)的Middlebrook 7H9中培养。对于巨噬细胞感染 ,MTB生长至光密度(OD600)0.8,然后以2,000g离心5分钟。用PBS将沉淀物洗涤两次,然后用2.5–3.5 mm的玻璃珠摇动颗粒 ,持续1分钟,以产生单细胞悬浮液。将细菌重悬于10 mL细胞培养基中,并以300g离心5分钟以去除团块 。确定OD600 ,并将细菌稀释为所需的MOI的适当OD(约合OD600 = 1等于每毫升108种细菌),然后添加到最少的体积中。2小时后,吸入接种物 ,用PBS洗涤两次细胞,并添加了新鲜培养基。然后将细胞孵育以获取适当的时间点,然后收集以进行分析 ,如以下各节所述 。
在甲醇中制备了333毫米Llome(CAT#4000725,BACHEM)的库存,并在紧密密封的管子中在-20°C冷冻。对于LLOME处理,除非图在图中另有说明 ,否则将培养基替换为含有1 mm llome的X-Vivo15(IPSDM),RPMI(HMDM)或DMEM(HELA和U2OS细胞),除非图形传说中另有说明。在所有对照条件下 ,使用各个细胞培养基中的甲醇(0.3%) 。
在X-Vivo15中制备了晶体二氧化硅(Min-U-SIL-15,US Silica)的溶液,并刺激细胞3小时 ,然后将它们加工为下游应用。在使用BAFA1(默克,B1793-10UT)的实验中,将IPSDM与100 nm溶液预孵育1小时。在二氧化硅处理过程中 ,将BAFA1保存在培养基中 。
对于裂解,将细胞用PBS洗涤一次,并在含有完整的 ,无EDTA的蛋白酶抑制剂(Roche)的Ripa缓冲液(Millipore)的冰上裂解。在LDS样品缓冲液和还原剂(Nupage,Life Technologies)中,将样品在95–100°C下煮5分钟,并在4-12%的Bis-Tris凝胶(Life Technologies)上运行。使用IBLOT 2干印迹系统(Thermo Fischer) ,程序P0将凝胶转移到PVDF膜上 。将膜在PBS中的5%脱脂奶粉中阻塞,加上0.05%的Tween-20(PBS-T),在室温下1小时 ,然后与原代抗体在4°C下孵育过夜。将膜在PBS-T中洗涤,并在室温下与HRP偶联的二抗孵育1小时。用增强的化学发光试剂(Biorad)开发膜,并在Amersham Imager 680仪器上成像。使用的抗体:来自ProteIntech ,抗P-EIF2α(Ser51)(9721)(9721),抗EIF2α(9722)和抗β-actin(8HH10D10D10,12226222262)的抗G3BP1(13057-2-AP)和抗G3BP2(16276-1-AP) 。来自Promega的抗小鼠(W4021)和抗兔(W4011)抗体。除了以1:10,000稀释时使用的HRP偶联抗体 ,所有抗体均以1:1,000的稀释度使用。
1,2-二烯酰基-SN-甘油-3-磷脂(DOPC)和1,2-二烯酰基-SN-甘油-3-磷酸 - 丝氨酸(DOPS)购自Avanti Polar Lipids 。从Atto-Tec获取荧光脂质染料647N涂料。聚乙烯醇(PVA,MW 145000)和氯仿(HPLC等级为99.8%)购自默克(Merck)。将脂质储备作为4 mm的氯仿溶液混合,含有0.1 mol%染料 ,并储存直至在-20°C下使用 。Fluorescein isothiocyanate isomer (FITC), poly (A) RNA, 4-(2-hydroxyethyl)−1-piperazineethanesulfonic acid buffer (HEPES), sucrose, glucose, carbonate buffer tablets, hydrochloric acid (HCl), sodium hydroxide (NaOH), magnesium chloride (MgCl2),从Sigma-Aldrich获得了二甲基磺氧化甲氧化物(DMSO)和氯化钠(NaCl)。所有溶液均使用来自SG水纯化系统的超纯水(Ultrapure Integra UV Plus,SG Wasseraufbereitung),电阻率为18.2MΩcm。
如所述,达到了甘氨酸的制备 。52。简而言之 ,将染色的大豆粉分散在15倍的水中(重量),并使用2 M NaOH溶液将pH调节至7.5。之后,将色散在4°C下以9,000克离心30分钟 。将硫酸钠(SB)添加到上清液(0.98 g l -1 SB)中 ,并用2 M HCl溶液将溶液的pH值调节至6.4,并在4°C保持在4°C过夜。然后在4°C的6,500克以6,500克离心色散。将获得的富含甘氨酸的沉淀物分散在五倍的水中,并将pH调节至7.4。然后将甘霉素溶液透析在4°C下透析两天 ,然后冷冻干燥以纯度为97.5% 。对于甘氨酸标记,在0.1 M碳酸盐缓冲液中制备20 mg ML -1的蛋白质溶液(pH 9)。将FITC溶液(DMSO中的4 mg ML -1)缓慢地加入蛋白质溶液中,温和搅拌至最终浓度为0.2 mg ml -1。在23°C搅拌3小时时 ,将样品在黑暗中孵育 。使用PD-10 Sephadex G-25脱盐柱(GE Healthcare)去除过量的染料,并将缓冲液交换为超纯水。通过添加0.1 M NaOH,将标记蛋白质溶液的pH调节为7.4。对于荧光显微镜实验 ,将该溶液的等分试样添加到工作甘氨酸溶液中,达到4%的最终浓度 。
G3BP1的表达和纯化是根据修饰的Guillén-Boixet等人进行的。简而言之,使用Baculovirus表达System53,用SF9昆虫细胞(表达系统 ,94-001 F)表达了重组His6-G3BP1-MBP和His6-GFP – G3BP1-MBP(表达系统,94-001 F)。在缓冲液A(50 mM HEPES/NaOH(pH 7.5),1 M NaCl ,5%(w/v)甘油,2 mM EDTA,2 mM DTT)中 ,在细胞裂解(LM10,微流体学)之后将上清液应用于定制的Hiflow链淀粉柱(新英格兰Biolabs) 。用10列体积缓冲液A洗涤柱,然后用10列量缓冲液B(50 mm HEPES/NaOH ,100 mM NaCl,5%甘油(W/V),2 mM EDTA ,2 mM EDTA,2 mM DTT,pH 7.5)。在缓冲液B中使用150μl1 mg ml-1 His标签的3 C蛋白酶(自制)进行卸载,并在室温下孵育8小时。The tag-free product was washed out with buffer B, applied to a 5 ml HiTRAP Q HP column (Cytiva) equilibrated in buffer B and eluted with a linear gradient against buffer A. Fractions containing the target protein were applied to a HiLoad Superdex 200-pg 26/600 column (Cytiva) equilibrated in buffer C (50 mM HEPES/NaOH, 150 mM NaCl,5%甘油(W/V) ,2 mM EDTA,2 mM DTT pH 7.5) 。将G3BP1馏分汇总,浓缩 ,用液氮冷冻,并存储在-80°C下。
DOPC和DOPC:DOPS 9:1含有0.1 mol%Atto 647n涂圈的GUV由PVA凝胶辅助Method54制备,该方法允许在囊泡肿胀过程中蛋白质封装。简而言之 ,用水和乙醇清洁了2个盖玻片,并用氮干燥。通过在60°C的去离子水中稀释到最终浓度为40 mg ml -1来制备PVA溶液 。PVA溶液的小等分试样(20–50 µL)散布在载玻片上,并在60°C下干燥1小时。脂质储备溶液(3–4μl)在涂有PVA涂层的玻璃上散布 ,并在室温下真空下保持1小时。使用两个盖玻片和一个2毫米厚的特氟龙垫片组装,并根据不同的实验填充:
对于G3BP1在GUV中的封装,在50 mm HEPES pH 7.5 ,100 mm NaCl,4 mM MGCL2中,肿胀缓冲液由10 µM GFP – G3BP1组成 。
对于甘氨酸蛋白封装,溶胀溶液在15 mM NaCl中含有10 mg ML-1甘氨酸素 ,对于pH触发的相分离实验,在pH 7.4时含有10 mM蔗糖。对于诱导盐驱动相的分离,溶液由pH 7.4的300 mM蔗糖组成。
在所有情况下 ,使用2 M NaOH溶液调整pH值 。30分钟后,将腔室打开,并仔细收集囊泡 ,以防止PVA从盖玻璃上脱离。使用冰点渗透压计(Gonotec Osmomat 3000)测量并调整渗透压。
由于几个实验限制,蛋白质的封装比在外部溶液中蛋白质的封装优先 。首先,蛋白质浓度是一个限制因素 ,并且在囊泡内的蛋白质所需的蛋白质比在外部溶液中蛋白质要少得多,在外部溶液中,在微流体实验中 ,蛋白质的蛋白质在恒定的流动下。其次,如果蛋白质在外部溶液中,则标记的蛋白质将使完整的视野荧光荧光呈荧光,这会阻碍实验和高精度成像的可视化。最后 ,最好将较低的pH放在外部,因为GUV的形成会导致中性而不是酸性pH值提高产量和质量更高 。重要的是要注意,结果独立于溶液位置的实验选择(内部与外部) ,因为凝结物的形成是由孔的外部和内部溶液混合驱动的(如图2和扩展数据图4),并且结果不取决于整个膜的溶液位置顺序。此外,由于GUV的尺寸较大 ,该膜几乎是平坦的,曲率可忽略不计(低于0.1μm -1),并且预计不会发挥作用。
微流体设备由级联GUV捕获系统组成 ,该系统在其他地方进行了详细描述。5555 。它是使用聚(二甲基硅氧烷)(PDMS)前保存和固化剂(Sylgard 184,Dow Corning GmbH)产生的,质量比为10:1。在80°C的聚合3小时后 ,用柱塞系统(KAI Medical)用活检打孔器和出口孔。然后使用高功率扩展的等离子清洁剂(Harrick Plasma)将PDMS芯片和玻璃盖板用血浆处理1分钟,然后将其粘合在一起 。在实验之前,通过在900相对离心力(Rotina 420 R,Hettich)离心 ,将所需量的溶液填充到微流体装置中。用Nemesys高精度注射器泵进行溶液交换。将其余标记的蛋白质在外部进行初始冲洗的流速(扩展数据图4F,G)设置为1μlmin -1 -1 40分钟,以确保至少10倍交换微流体设备的内部体积(〜4 µL) 。为了改变pH并引入低渗溶液 ,使用2μlmin -1的较高速度来确保快速交换,以避免由于被动质子渗透而引起的相位分离56,57,58。在此高流量下,将囊泡推到微流体设备的柱子上 ,并可以观察到小变形(图2A)。完整的溶液交换后,将流速降低至0.035μlmin -1,以防止囊泡运动并促进成像 。
低音缓冲液由20 mM HEPE ,100 mM NaCl,4 mM MGCL2,pH 5用于G3BP1实验。对于甘氨酸pH驱动的相分离 ,外部低音溶液在pH 4.8处进行去离子水,并使用2 m HCl的溶液调节pH。对于由NaCl触发的相分离的实验,低渗性缓冲液由100 mM NaCl溶液pH 7.4组成 。
Guillén-Boixet等人10。为了形成冷凝物,20 µL含有5 µM GFP – G3BP1和200 ng µl-1的溶液 ,在50 mM HEPES中的Poly(A)-RNA,100 mM NaCl,4 mM MGCL2直接放置在玻璃滑板上 ,并通过共聚焦显微镜直接将其置于玻璃滑膜上。
为了模拟脂质囊泡的孔隙和堵塞,我们考虑了一个最小的粗粒分子动力学系统,其中蛋白质的蛋白溶液通过分散在隐式溶剂中的珠子描述。该膜被描述为模仿生物膜的机械性能的单层厚的流体弹性层 。我们调整不同隔室中溶液珠之间的相互作用 ,以捕获细胞质和内体蛋白质溶液之间的差异,并探索系统对不同程度的膜孔的反应。有关分子动力学的执行方式的详细信息在补充信息和补充表1中。
为了表征和理解蛋白质冷凝物对受损囊泡的堵塞作用,我们可以跟踪囊泡表面的发展方式 ,以及在整个模拟过程中最初(内部或外部)中最初在每个隔室(内部或外部)混合的颗粒 。
为此,第一个基本步骤是从模型粒子位置和方向重建膜表面,为此 ,我们根据Ball Pivot算法60使用自定义的Python Code59。我们的分析提供了囊泡表面积以及局部边界和方向的估计,以及毛孔及其周长的集合,这使我们能够评估孔隙闭合。
一旦定义了囊泡表面,我们就会通过在溶质和蛋白质颗粒(Python61中的Ovito库的一部分)上运行聚类算法来评估凝结 。这使我们能够区分冷凝水颗粒和溶液颗粒 ,并计算液滴特性(例如质量或回旋半径)以及随时间的总液滴生长速率。一旦确定了保留在溶液中的颗粒,我们就可以确定它们属于哪个隔室(在囊泡内或外部),并且通过与初始条件进行比较 ,我们可以确定溶液交换通量。
为了将颗粒分类为内腔或外管道,我们确定每个粒子最接近的六个表面三角形(使用弗洛伊德库中的邻居列表算法用于Python62),并沿着连接粒子及其每个邻居三角形中心的线沿线计算单位矢量 。然后 ,我们用表面的局部正常媒介计算这些单位向量的点产物ρ(先前使用球枢轴算法鉴定)。最后,如果平均点产物ρ> 0.5我们将粒子分类为囊泡内部。相反,如果ρ< −0.5 we classify the particle as being outside the vesicle. In this analysis, particles that are close to the pore present dot products close to zero (|ρ| < 0.5), and in this case we compare their position to the pore’s centre of mass to determine their compartment.
Once we have a list of inner particles, outer particles and droplet particles, we can define fluxes by comparing these values across the simulation and characterize the mixing of solutions and the condensate growth in different conditions.
After the indicated treatment, cells were washed once with PBS and fixed with 4% methanol-free paraformaldehyde (PFA) in PBS for 15 min. After 3 washes with PBS, cells were permeabilized using a 0.5% Triton X-100 (Sigma)/PBS solution for 10 min. Cells were then immunostained using the corresponding antibodies. Antibodies were: anti-G3BP1 (13057-2-AP) or alternatively, anti-G3BP1 (66486-1-Ig, sc-365338 AF546), anti-G3BP2 (16276-1-AP) anti-TIA1 (12133-2-AP), anti-PABPC1 (10970-1-AP), anti-ALIX (12422-1-AP), anti-CHMP2a (10477-1-AP), anti-CHMP4b (13683-1-AP), anti-annexin A1 (66344-1-Ig), anti-annexin A2 (66035-1-Ig), anti-EIF3B (10319-1-AP), and anti-EIF4G1 (15704-1-AP) from Proteintech. Anti-GAL-3 (125410) and anti-LAMP-1 (121610) from Biolegend. Anti-p62 (GTX111393) from GeneTex, anti-phospho TBK1 (5483 T) from Cell Signalling Technologies. Anti-PI4K2a (B-5, sc390026) and anti-ORP9 (A-7, sc398961) from Santa Cruz. Antibodies were used at 1:200 dilution. Images were acquired on Ibidi glass bottom slides (81817) using a Leica SP8 confocal microscope (for Mtb fixed imaging and silica crystals experiments) or using a VT-iSIM superresolution imaging system (Visitech International). Nuclear staining was performed using 300 nM DAPI (Life Technologies, D3571) in PBS for 5 min. The area of GAL-3 and stress puncta per cell was evaluated using the image analysis software FIJI/ImageJ as described below.
Fluorescence recovery after photobleaching (FRAP) experiments were performed using a Zeiss Invert880 microscope system (Zeiss) and the bleaching module of Zeiss ZEN software. Photobleaching of G3BP1–mEGFP was achieved using a 488-nm laser at a scan speed = 1 (pixel dwell 131.07 ms). Images were captured at 20 or 30-s intervals for at least 20 min. The photobleaching started after three time points that were used as the basal intensity reference.
Confocal Leica SP8 microscope equipped with a 63×, 1.2 NA water-immersion objective and a 40× 1.3 NA oil immersion objective (Leica) was used for imaging. FITC and ATTO 647N-DOPE were excited using the 488 nm and 633 nm laser lines, respectively and signal was collected between 500–600 nm for FITC and 650–720 nm for ATTO. Time-lapse sequences (xyt) of individual GUVs were acquired at 650 ms per frame using the bidirectional acquisition mode.
Thirty thousand iPSDM were seeded into a ViewPlate glass bottom 96 well plate (PerkinElmer) and treated with LLOMe or infected with Mtb as described above. The plate was sealed with parafilm and placed in a pre-heated (37 °C) Opera Phenix microscope with a 40× or 60× water-immersion lens (PerkinElmer) with 5% CO2. Capture settings were: LysoTracker Red was excited with the 561 nm laser at 10% power with 100 ms exposure. MitoTracker Deep Red FM (M22426, Thermo Fischer), iABP probe and Mtb E2-Crimson were excited with the 640 nm laser at 10% power with 100 ms exposure. DAPI was excited with the 405 nm laser at 20% power with 100 ms exposure. At least 20 fields per well were imaged in all the experiments. Images were acquired at 1,020 × 1,020 pixels using Harmony 4.9 high-content imaging and analysis software (PerkinElmer).
iPSDMs transfected with GAL-3–RFP, G3BP1–mEGFP or LAMP1–RFP were treated with LLOMe (1 mM) and imaged on a VT-iSIM superresolution imaging system (Visitech International), using an Olympus IX83 microscope, 150×/1.45 Apochromat objective (UAPON150XOTIRF), ASI motorized stage with piezo Z, and 2× Prime BSI Express scientific CMOS cameras (Teledyne Photometrics). Cells were always in the stage incubator at 37 °C and 5% CO2. Simultaneous GFP and mCherry imaging was done using 488 nm and 560 nm laser excitation and ET525/50 m and ET600/50 m emission filters (Chroma), respectively. Z-stacks (100 nm z-step) were acquired at the intervals indicated in the figure legends. The microscope was controlled with CellSens software (Olympus). Image processing and deconvolution was done using Huygens Essential software (Scientific Volume Imaging). For 3D imaging, spatial deconvolution and 3D surface-rendering reconstruction, z-stack slices were defined each 200 nm (if confocal microscope was used) or 100 nm (if VT-iSIM microscope was used) and images were processed using Huygens Essential Software (Scientific Volume Imaging).
Forty thousand cells (background indicated in the figure legends) were seeded into a ViewPlate glass bottom 96 well plate (PerkinElmer). Cells were loaded with the nuclear dye Nuclear Green LCS1 (Abcam) at a dilution of 1:5,000 and 25 nM LysoTracker DND-99 (Thermo Fisher Scientific) for 20 min. The cells were washed twice in X-VIVO15, and the medium was replaced with X-VIVO15 containing 25 nM LysoTracker. The cells were imaged every 1 min at 37 °C, 5% CO2 using an Opera Phenix microscope (PerkinElmer). First, a baseline was established by imaging 3 time points, followed by the addition of LLOMe to a final concentration of 1 mM. After 2 time points, the cells were washed 3 times with X-VIVO15 and the medium was replaced with X-VIVO15 containing 25 nM LysoTracker, and lysosomal recovery was followed for 20 min. Analysis was done as indicated below (see ‘Imaging analysis’).
Wild-type and G3BP-DKO U2OS cells were seeded into a PerkinElmer Cell Carrier Ultra 96 well plate (PerkinElmer) and incubated with 25 µg ml−1 10K-dextran conjugated to Alexa Fluor 647 (D22914; Thermo Fisher Scientific) in DMEM for 12–16 h, and then in fresh DMEM for 2–4 h (chase) to allow dextran to reach the lysosomes3. After that, cells were treated with LLOMe (2 mM, 2 min), cells were then washed within a min and imaged for 40 min after in fresh medium. Images were acquired at 1 min intervals.
Tissue sections (see ‘Tissue sectioning’) on SuperFrost Plus Adhesion slides (Fisher Scientific, 11950657) were unfrozen at room temperature and and permeabilized with a 0.5% solution of Tween-20/PBS for 20 min. After that, samples were washed twice with PBS and stained with the corresponding primary antibodies (dilution 1:100) for 2 h. The coverslips were then washed twice with PBS and incubated with the corresponding Alexa Fluor (Thermo Fischer) secondary antibodies (dilution 1:700) for 1 h. After two washes with PBS, the samples were mounted using Dako fluorescence mounting medium (S3023).
iPSDM cultured in µ-Slide 18-Well Glass Bottom plates (Ibidi) were fixed in 4% PFA for 10 min, PFA aspirated, and 100% cold methanol added to each well for 10 min. Methanol was replaced with 70% ethanol and incubated for 10 min. The ethanol was aspirated and 1 M Tris, pH 8.0 added to each well for 5 min. After Tris removal, hybridization buffer was added containing the dilution of 5′-labelled Cy3-Oligo-dT(20) stock (Integrated DNA Technologies) for a final concentration of 1 ng μl−1. Hybridization was carried out at 37 °C for 2 h. After hybridization, samples were washed once with 4× SSC and then once with 2× SSC (all DEPC-treated). Incubation with primary antibodies was in 2× SSC + 0.1% Triton X-100 for 2 h, washed three times with 2× SSC, and then incubated with secondary antibodies for 1 h at room temperature. Hybridization buffer composition: 1 mg ml−1 Yeast tRNA (AM7119 Thermo Fischer), 0.005% BSA, 10% dextran sulfate (D8906-5G, Merck), 25% Formamide (17899, Thermo Fischer) 20× SSC + DEPC water so that final buffer volume is in 2× SSC.
Samples were fixed by adding a mixture of 8% PFA in 200 mM HEPES buffer to culture medium (v/v) and incubated at room temperature for 15 min then replaced with 4% PFA in 100 mM HEPES for 30 min before imaging by confocal microscope. After imaging by confocal, samples were transferred to 1% glutaraldehyde in 100 mM HEPES buffer.
Fluorescently imaged samples were processed for correlative light and electron microscopy in a Biowave Pro (Pelco) with use of microwave energy and vacuum. Cells were twice washed in HEPES (Sigma-Aldrich H0887) at 250 W for 40 s, post-fixed using a mixture of 2% osmium tetroxide (Taab O011) 1.5% potassium ferricyanide (Taab, P018) (v/v) at equal ratio for 14 min at 100 W power (with/without vacuum 20 inch Hg at 2-min intervals). Samples were washed with distilled water twice on the bench and twice again in the Biowave 250 W for 40 s. Samples were stained with 1 % aqueous uranyl acetate (Agar scientific AGR1260A) in distilled water (w/v) for 14 min at 100 W power (with/without vacuum 20 inch Hg at 2-min intervals) then washed using the same settings as before. Samples were dehydrated using a step-wise acetone series of 50, 75, 90 and 100%, then washed 4 times in absolute acetone at 250 W for 40 s per step. Samples were infiltrated with a dilution series of 25, 50, 75, 100% Durcupan ACM (Sigma-Aldrich 44610) (v/v) resin to propylene oxide. Each step was for 3 min at 250 W power (with or without vacuum 20 inch Hg at 30 s intervals). Samples were then cured for a minimum of 48 h at 60 °C.
Referring to grid coordinates, the sample block was trimmed, coarsely by a razor blade then finely trimmed using a 35° ultrasonic, oscillating diamond knife (DiATOME, Switzerland) set at a cutting speed of 0.6 mm s−1, a frequency set by automatic mode and a voltage of 6.0 V, on a ultramicrotome EM UC7 (Leica Microsystems, Germany) to remove all excess resin surrounding the region of interest (ROI). Ribbons were cut to a thickness of 65 nm and Images were acquired using a JEOL JEM-1400 series 120 kV transmission electron microscope.
Fluorescent images were converted to tiff file format and liner adjustments made to brightness and contrast using FIJI (version 2.9.0/1.53t). Fluorescent images were aligned to serialEM micrographs (TrakEM2) using BigWarp_fiji_7.0.7 plugin. No less than 10 independent fiducials were chosen per alignment for 3D image registration. When the fiducial registration error was greater than the predicted registration error, a non-rigid transformation (a nonlinear transformation based on spline interpolation, after an initial rigid transformation) was applied.
An event was considered positive when the fluorescence signal was at least three times greater than the mean background (determined previously to the addition of LLOMe). Intensities were quantified selecting the corresponding ROI in FIJI/ImageJ. G3BP1+ and GAL-3+ events were manually tracked over time and the time registered when the first positive event was detected. At least 20 events per experiment were annotated. The percentage of ‘capping events’ was determined considering the amount of double-positive G3BP1+/GAL-3+ events that presented a polarized G3BP1 fluorescence signal distribution in comparison with the distribution observed for GAL-3+ vesicles. To this end, GAL-3+ areas were segmented and the mean intensity of G3BP1 in those areas determined. A G3BP1+ event was considered polarized (in ‘cap pattern’) when the G3BP1 mean intensity, of a ROI in proximity of a GAL-3+ event, was at least two times greater than the G3BP1 mean intensity corresponding to the segmented (overlapping) GAL-3+ area. For fluorescence intensity or puncta area over time analysis, the corresponding values after segmentation were plotted using the geom_smooth function in R Studio (method = “loess”) (see source data for Fig. 1).
To determine whether the distances between points in group A (G3BP1+) and points in group B (GAL-3+) were significantly different from the distances between points in group A and randomly generated points, we performed a spatial point pattern analysis using the spatstat package in R (version 3.0–6). First, a point pattern object was created from the x and y coordinates of the data using the ppp function. The lambda value, which represents the intensity of the point pattern for group A, was then calculated as the number of points in group A divided by the area of the point pattern. Next, a random point pattern with the same window as the original point pattern was generated using the runifpoint function. The distances between points in group A and points in group B were then calculated using the nncross function, and the distances between points in group A and the randomly generated points were calculated in a similar way. The number of simulated distances that were less than or equal to the observed distances was counted and used to calculate a P value using a Monte Carlo simulation. A total of 1,000 simulations were performed to estimate the P value. Finally, a boxplot was created to visually compare the distribution of observed distances between points in group A and points in group B to the distribution of distances between points in group A and randomly generated points.
Analysis was done in Fiji/ImageJ using the sequence Image>Adjust>使用菜单命令分析>分析粒子确定阈值 ,然后在分段图像中的点或区域 。尺寸仅限于大于0.1 um的颗粒,循环度仅限于0.4至1之间的值。
使用fiji/imageJ上的EZColocalization插件和Spearman的等级相关系数(SRCC)值分析VT-ISIM图像。分析是在150 nm的单个Z-stack部分进行的。
IPSDM与IABP智能组织蛋白酶成像探针(40200-100,Vergent Bioscience)的1 µM溶液在37°C和5%CO2孵育3小时 。基于核染色和使用Harmony 4.9软件的发现斑点和形态模块进行分割的溶酶体分割单细胞分割。之后 ,量化了溶酶体强度值(650-760 EM)和细胞形态参数。
使用Nucgreen核信号对IPSDM进行了分割,并在应用逆灰色调色板并找到Harmony 4.9软件的细胞模块后基于细胞分割的核模块 。使用斑点构建块(局部最大值)鉴定了lysotracker Puncta。将每个单元格的点强度和时间点标准化为添加Llome之前的相对点强度的平均值。对于每个实验,每个条件至少分析了300个细胞 。
使用40倍物镜在Opera Phenix显微镜上获取了MTB感染的IPSDM的图像,每个孔至少有20个视野(每个条件下有3个井) ,并以和谐4.9进行分析。基于DAPI对细胞进行分割,不包括接触成像区域边缘的任何细胞。使用Harmony的Find斑点检测到细菌 。然后确定每个细胞中的总细菌区域。在R Studio中导出数据并分析数据,以计算每个时间点的每个条件的平均MTB面积 ,所有三个井都汇总了。每个条件和时间点至少进行了三个独立的实验 。
用野生型MTB Wasabi Hygr或MTBΔRD1E2-Crimson Kanr感染了六到八周龄的雌性C3HEB/FEJ小鼠。样本量根据到达指南和先前的研究确定64。每个感染时间每组使用五只动物。雌性用于安全和空间分配限制,因为被感染的小鼠包含在BSL3中 。所有小鼠均在BSL3笼中保持在22±2°C,相对湿度为55±10%。本研究没有随机分组或盲目化。对于低剂量的气溶胶感染实验 ,所有细菌均在指数中期使用,并校准了Glascol气溶胶发生器,以提供野生型MTB Wasabi Hygr/肺和500 CFU的MTBΔRD1E2 E2-ΔRD1E2-CRIMSON KANR/LUNGN的大约100个菌落形成单位(CFU) 。感染56天 ,在4%PFA中灌注肺部以进行荧光显微镜分析。将肺在0.1 M HEPES缓冲液(pH 7.4)中用0.2 M蔗糖平衡1小时,然后转移到含有OCT培养基的硅霉菌(Agar Scientific,Agr1180)。然后将含有OCT和肺部的模具转移到干冰中并冷冻以准备切片 。使用Leica CM30505S低温器(CT-18°C ,OT-20°C)切割切片,尺寸为8μm。在Superfrost加粘附载玻片(Fisher Scientific,11950657)上收集切片,并在进一步加工之前存储在-80°C下。
使用GraphPad Prism 10软件或R Studio 2023.03.0(R版本4.2.2)进行统计分析 。使用R 4.2.2或Harmony 4.9软件获得了高含量成像分析和平均值。图的传奇人物中提到了生物学重复的数量 ,进行的统计分析和所使用的事后测试。数据的统计显着性通过告知p值或星号,其中 *p <0.05,** p <0.01 ,*** p <0.001;或NS,并不重要 。将图形绘制在GraphPad Prism软件或使用R Studio 2023.03.0(R版本4.2.2)中。RNA序列数据是从先前的研究42获得的,并使用morpheus(https://software.broadinstitute.org/morpheus/)绘制。使用Biorender.com创建了原理图。
这项研究涉及使用Kolf2人IPS细胞 ,英格兰公共卫生文化收藏,目录编号77650100,以及使用WTC人MEGFP标记的G3BP1 IPS IPS细胞(Coriell Institute ,AICS-0082 Cl.1) 。人类细胞的使用得到了道德委员会的涵盖和批准,并由弗朗西斯·克里克研究所(Francis Crick Institute Institute Biolical Safety Safety Coment)的实践守则在Crick(Project hta17)注册的项目中,根据人体组织授权许可证编号12650。
有关研究设计的更多信息可在与本文有关的自然投资组合报告摘要中获得。
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