STAR Protocols最新文献

Standard flow cytometry-based assays can determine the cytotoxicity of immune effector cells, but it is challenging to monitor the dynamic processes of cytotoxicity. Here, we present a protocol for continuous observation of natural killer (NK) cell-mediated cytotoxicity with microwell arrays using an automated microscope. We describe steps for isolating and labeling primary NK cells, loading cells onto microwell arrays, monitoring target wells, and image analysis. This protocol facilitates observation of the dynamics of immune-target cell interactions at the single-cell level. For complete details on the use and execution of this protocol, please refer to Li et al.¹.

Confocal imaging is a powerful tool capable of analyzing cellular spatial data within a given tissue. Here, we present a protocol for preparing optically cleared extensor digitorum longus (EDL) skeletal muscle samples suitable for confocal imaging/computational analysis. We describe steps for sample preparation (including perfusion fixation and tissue clearing of muscle samples), image acquisition, and computational analysis, with sample segmentation/3D rendering outlined. This protocol can be applied to characterize various cell types, including muscle satellite cells (muscle stem cells) and capillary endothelial cells within rodent skeletal muscle. For complete details on the use and execution of this protocol, please refer to Verma et al.,¹ Verma et al.,² Karthikeyan et al.,³ and Karthikeyan et al.⁴.

Here, we present a protocol for assessing the impact of a chemogenetic manipulation in a subpopulation of the hypothalamic neurons on aging and lifespan control using a mouse model developed specifically for this purpose. We describe steps for stereotaxic viral injection and assess inter-tissue communication between protein phosphatase 1 regulatory subunit 17 (Ppp1r17)-expressing neurons in the dorsomedial hypothalamus and white adipose tissue. We then detail procedures for lifespan measurements following chemogenetic manipulation in aged mice. For complete details on the use and execution of this protocol, please refer to Tokizane et al.¹.

The plastid-encoded RNA polymerase (PEP) plays an essential role in the transcription of the chloroplast genome. Here, we present a strategy to purify the transcriptionally active protein complex from transplastomic tobacco (Nicotiana tabacum) lines in which one of the PEP core subunits is fused to an epitope tag. We describe experimental procedures for designing transformation constructs for PEP purification, selection, and analysis of transplastomic tobacco plants. We then detail the steps for purifying PEP from the transplastomic tobacco leaves. For complete details on the use and execution of this protocol, please refer to Wu et al.¹.

Intracellular microorganisms like viruses and bacteria impact immune cell function. However, detection of these microbes is challenging as the majority exist in a non-culturable state. This protocol presents detailed steps to investigate intracellular microbial diversity using single-cell RNA sequencing (scRNA-seq) in immune-cells of SARS-CoV-2-positive and recovered patients. We present a workflow from sample collection to library preparation, covering peripheral blood mononuclear cell (PBMC) isolation, single-cell labeling, cartridge priming, and cell lysis. We outline the steps for analyzing the scRNA-seq data, from data quality control (QC) to detection of intracellular microbes. For complete details on the use and execution of this protocol, please refer to Yadav et al.¹.

Tumor Treating Fields (TTFields) are electric fields clinically approved for cancer treatment, delivered via arrays attached to the patient's skin. Here, we present a protocol for applying TTFields to torso orthotopic and subcutaneous mouse tumor models using the inovivo system. We guide users on proper system component connections, study protocol design, mouse fur depilation, array application, and treatment condition adjustment and monitoring. The inovivo system allows for the concurrent application of TTFields with standard cancer therapies. For complete details on the use and execution of this protocol, please refer to Barsheshet et al.¹.

Air-liquid interface (ALI) culture can differentiate airway epithelial cells to recapitulate the respiratory tract in vitro. Here, we present a protocol for isolating and culturing nasal epithelial cells from turbinate tissues for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We describe steps to overcome challenges of imaging fragile cultures, detect the production of mucus, and quantify intracellular virus post-SARS-CoV-2 infection. We present data on the optimal duration of ALI maturation prior to experimentation and describe which steps can be altered to optimize testing of specific hypotheses.

Here, we present a protocol for isolating microvessels from fresh or snap-frozen brain tissue from mice and humans, followed by visualization of RNA utilizing RNAscope hybridization for quantification of mRNA. We describe the steps for sample preparation and isolation, fixation, and hybridization. This protocol was specifically designed to integrate with RNAscope in situ hybridization. Although the protocol was developed in a mouse model, it can be optimized for use in other organisms, including human brain samples.

Pancreatic ductal adenocarcinoma (PDAC) organoids that simulate the tumor microenvironment (TME) are an effective tool to identify how TME affects PDAC malignancy. We present a protocol for generating a fused pancreatic cancer organoid (FPCO) that partly reproduces the TME, including heterogeneous cancer-associated fibroblasts (CAFs), using patient-derived PDAC cells and human-induced pluripotent cell-derived endothelial and mesenchymal cells. We also describe the procedure for analyzing FPCO characteristics. FPCO can provide a platform for establishing a reliable drug screening system. For complete details on the use and execution of this protocol, please refer to Takeuchi et al.¹.

Recently, studies have emerged exploring the potential application of fecal microbiota transplantation (FMT) in pre-clinical settings. Here, we present a protocol for FMT for mice housed in a specific pathogen-free (SPF) facility. We describe steps for sample collection, microaerophilic processing of freshly collected fecal pellets, and administration through oral gavage. We then detail procedures for the engraftment of the bacterial community. This protocol focuses on age- and gender-matched, healthy donor mice using a mobile and cost-effective alternative to an anoxic cabinet.