Visualizing neuroinflammation with fluorescence and luminescent lanthanide-based in situ hybridization

Lanthanide Complex for Single-Molecule Fluorescent in Situ Hybridization and Background-Free Imaging

Traditional single-molecule fluorescence in situ hybridization (smFISH) methods for RNA detection often face sensitivity challenges due to the low fluorescence intensity of the probe. Also, short-lived autofluorescence complicates obtaining clear signals from tissue sections. In response, we have developed an smFISH probe using highly grafted lanthanide complexes to address both concentration quenching and autofluorescence background. Our approach involves an oligo PCR incorporating azide-dUTP, enabling conjugation with lanthanide complexes. This method has proven to be stable, convenient, and cost-effective. Notably, for the mRNA detection in SKBR3 cells, the lanthanide probe group exhibited 2.5 times higher luminescence intensity and detected 3 times more signal points in cells compared with the Cy3 group. Furthermore, we successfully applied the probe to image HER2 mRNA molecules in breast cancer FFPE tissue sections, achieving a 2.7-fold improvement in sensitivity compared to Cy3-based probes. These results emphasize the potential of time-resolved smFISH as a highly sensitive method for nucleic acid detection, free of background fluorescence interference.

Emergency Treatment and Photoacoustic Assessment of Spinal Cord Injury Using Reversible Dual-Signal Transform-Based Selenium Antioxidant

Spinal cord injury (SCI), following explosive oxidative stress, causes an abrupt and irreversible pathological deterioration of the central nervous system. Thus, preventing secondary injuries caused by reactive oxygen species (ROS), as well as monitoring and assessing the recovery from SCI are critical for the emergency treatment of SCI. Herein, an emergency treatment strategy is developed for SCI based on the selenium (Se) matrix antioxidant system to effectively inhibit oxidative stress-induced damage and simultaneously real-time evaluate the severity of SCI using a reversible dual-photoacoustic signal (680 and 750 nm). Within the emergency treatment and photoacoustic severity assessment (ETPSA) strategy, the designed Se loaded boron dipyrromethene dye with a double hydroxyl group (Se@BDP-DOH) is simultaneously used as a sensitive reporter group and an excellent antioxidant for effectively eliminating explosive oxidative stress. Se@BDP-DOH is found to promote the recovery of both spinal cord tissue and locomotor function in mice with SCI. Furthermore, ETPSA strategy synergistically enhanced ROS consumption via the caveolin 1 (Cav 1)-related pathways, as confirmed upon treatment with Cav 1 siRNA. Therefore, the ETPSA strategy is a potential tool for improving emergency treatment and photoacoustic assessment of SCI.

Macrophage Identification In Situ

Understanding the processes of inflammation and tissue regeneration after injury is of great importance. For a long time, macrophages have been known to play a central role during different stages of inflammation and tissue regeneration. However, the molecular and cellular mechanisms by which they exert their effects are as yet mostly unknown. While in vitro macrophages have been characterized, recent progress in macrophage biology studies revealed that macrophages in vivo exhibited distinctive features. Actually, the precise characterization of the macrophages in vivo is essential to develop new healing treatments and can be approached via in situ analyses. Nowadays, the characterization of macrophages in situ has improved significantly using antigen surface markers and cytokine secretion identification resulting in specific patterns. This review aims for a comprehensive overview of different tools used for in situ macrophage identification, reporter genes, immunolabeling and in situ hybridization, discussing their advantages and limitations.

Glial Cell Line-Derived Neurotrophic Factor Family Ligands, Players at the Interface of Neuroinflammation and Neuroprotection: Focus Onto the Glia

Well-known effects of neurotrophic factors are related to supporting the survival and functioning of various neuronal populations in the body. However, these proteins seem to also play less well-documented roles in glial cells, thus, influencing neuroinflammation. This article summarizes available data on the effects of glial cell line derived neurotrophic factor (GDNF) family ligands (GFLs), proteins providing trophic support to dopaminergic, sensory, motor and many other neuronal populations, in non-neuronal cells contributing to the development and maintenance of neuropathic pain. The paper also contains our own limited data describing the effects of small molecules targeting GFL receptors on the expression of the satellite glial marker IBA1 in dorsal root ganglia of rats with surgery- and diabetes-induced neuropathy. In our experiments activation of GFLs receptors with either GFLs or small molecule agonists downregulated the expression of IBA1 in this tissue of experimental animals. While it can be a secondary effect due to a supportive role of GFLs in neuronal cells, growing body of evidence indicates that GFL receptors are expressed in glial and peripheral immune system cells. Thus, targeting GFL receptors with either proteins or small molecules may directly suppress the activation of glial and immune system cells and, therefore, reduce neuroinflammation. As neuroinflammation is considered to be an important contributor to the process of neurodegeneration these data further support research efforts to modulate the activity of GFL receptors in order to develop disease-modifying treatments for neurodegenerative disorders and neuropathic pain that target both neuronal and glial cells.

Science convergence applied to psychoneuroimmunology: The future of measurement and imaging

The future of psychoneuroimmunology requires breakthrough technology discoveries. These next generation technologies need to address the unique challenges that are raised by imaging and measuring the activity of the neuroimmune interface in health and disease. The complexity of this challenge is centred around the multidimensionality of the neuroimmune system. These include novel challenges of capturing potent and rare biological signals over long times and vast anatomical distances. Here is a summary of the outcomes of the investments made by the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics which was presented as part of the PNIRSAsia-Pacific symposium at the 2019 International Brain Research Organization.

Dialing in the dialogue between inflammation and the brain

The nervous and immune systems communicate with one another and jointly influence functional responses. To highlight the many advances on this hot topic, Brain, Behavior, and Immunity conceptualized a Special Issue entitled "Dialing in the Dialogue Between Inflammation and the Brain." Recent advances and exciting developments in understanding communication pathways between the brain and the immune system during both physiological and pathological insults are highlighted.

A technical review and guide to RNA fluorescence in situ hybridization

RNA-fluorescence in situ hybridization (FISH) is a powerful tool to visualize target messenger RNA transcripts in cultured cells, tissue sections or whole-mount preparations. As the technique has been developed over time, an ever-increasing number of divergent protocols have been published. There is now a broad selection of options available to facilitate proper tissue preparation, hybridization, and post-hybridization background removal to achieve optimal results. Here we review the technical aspects of RNA-FISH, examining the most common methods associated with different sample types including cytological preparations and whole-mounts. We discuss the application of commonly used reagents for tissue preparation, hybridization, and post-hybridization washing and provide explanations of the functional roles for each reagent. We also discuss the available probe types and necessary controls to accurately visualize gene expression. Finally, we review the most recent advances in FISH technology that facilitate both highly multiplexed experiments and signal amplification for individual targets. Taken together, this information will guide the methods development process for investigators that seek to perform FISH in organisms that lack documented or optimized protocols.