Nature Biomedical Engineering

A stealthy neural recorder for the study of behaviour in primates
Oh S, Jekal J, Won J, Lim KS, Jeon CY, Park J, Yeo HG, Kim YG, Lee YH, Ha LJ, Jung HH, Yea J, Lee H, Ha J, Kim J, Lee D, Song S, Son J, Yu TS, Lee J, Lee S, Lee J, Kim BH, Choi JW, Rah JC, Song YM, Jeong JW, Choi HJ, Xu S, Lee Y and Jang KI
By monitoring brain neural signals, neural recorders allow for the study of neurological mechanisms underlying specific behavioural and cognitive states. However, the large brain volumes of non-human primates and their extensive range of uncontrolled movements and inherent wildness make it difficult to carry out covert and long-term recording and analysis of deep-brain neural signals. Here we report the development and performance of a stealthy neural recorder for the study of naturalistic behaviours in non-human primates. The neural recorder includes a fully implantable wireless and battery-free module for the recording of local field potentials and accelerometry data in real time, a flexible 32-electrode neural probe with a resorbable insertion shuttle, and a repeater coil-based wireless-power-transfer system operating at the body scale. We used the device to record neurobehavioural data for over 1 month in a freely moving monkey and leveraged the recorded data to train an artificial intelligence model for the classification of the animals' eating behaviours.
Seeing ageing through retinal images
Pàmies P
Endocisternal interfaces for minimally invasive neural stimulation and recording of the brain and spinal cord
Chen JC, Dhuliyawalla A, Garcia R, Robledo A, Woods JE, Alrashdan F, O'Leary S, Husain A, Price A, Crosby S, Felicella MM, Wakhloo AK, Karas P, Provenza N, Goodman W, Sheth SA, Sheth SA, Robinson JT and Kan P
Minimally invasive neural interfaces can be used to diagnose, manage and treat many disorders, with reduced risks of surgical complications. However, endovascular probes lack access to key cortical, subcortical and spinal targets, and are not typically explantable after endothelialization. Here we report the development and testing, in sheep, of endocisternal neural interfaces that approach brain and spinal cord targets through inner and outer spaces filled with cerebrospinal fluid. Thus, the interfaces gain access to the entire brain convexity, to deep brain structures within the ventricles and to the spinal cord from the spinal subarachnoid space. We combined an endocisternal neural interface with wireless miniature magnetoelectrically powered bioelectronics so that it can be freely navigated percutaneously from the spinal space to the cranial subarachnoid space, and from the cranial subarachnoid space to the ventricles. In sheep, we show recording and stimulation functions, as well as repositioning of the flexible electrodes and explantation of the interface after chronic implantation. Minimally invasive endocisternal bioelectronics may enable chronic and transient therapies, particularly for stroke rehabilitation and epilepsy monitoring.
Setting morphogen gradients
Caprettini V
Dyeing mice transparent
Griffo A
Stress impacts immunity via the gut
Haskell J
Ablation of FAS confers allogeneic CD3 CAR T cells with resistance to rejection by T cells and natural killer cells
Menegatti S, Lopez-Cobo S, Sutra Del Galy A, Fuentealba J, Silva L, Perrin L, Heurtebise-Chrétien S, Pottez-Jouatte V, Darbois A, Burgdorf N, Privat AL, Simon A, Laprie-Sentenac M, Saitakis M, Wick B, Webber BR, Moriarity BS, Lantz O, Amigorena S and Menger L
Allogeneic chimaeric antigen receptor T cells (allo-CAR T cells) derived from healthy donors could provide rapid access to standardized and affordable batches of therapeutic cells if their rejection by the host's immune system is avoided. Here, by means of an in vivo genome-wide CRISPR knockout screen, we show that the deletion of Fas or B2m in allo- T cells increases their survival in immunocompetent mice. Human B2M allo-CAR T cells become highly sensitive to rejection mediated by natural killer (NK) cells, whereas FAS CAR T cells expressing normal levels of human leukocyte antigen I remain resistant to NK cells. CD3 FAS CAR T cells outperformed CD3 B2M CAR T cells in the control of leukaemia growth in mice under allogeneic pressure by T cells and NK cells. The partial protection of CD3 FAS allo-CAR T cells from cellular rejection may improve the efficacy of allogeneic cellular therapies in patients with cancer.
Endocytic tagging for degradation
Almeida FV
Clinical validation of a wearable ultrasound sensor of blood pressure
Zhou S, Park G, Longardner K, Lin M, Qi B, Yang X, Gao X, Huang H, Chen X, Bian Y, Hu H, Wu RS, Yue W, Li M, Lu C, Wang R, Qin S, Tasali E, Karrison T, Thomas I, Smarr B, Kistler EB, Khiami BA, Litvan I and Xu S
Options for the continuous and non-invasive monitoring of blood pressure are limited. Cuff-based sphygmomanometers are widely available, yet provide only discrete measurements. The clinical gold-standard approach for the continuous monitoring of blood pressure requires an arterial line, which is too invasive for routine use. Wearable ultrasound for the continuous and non-invasive monitoring of blood pressure promises to elevate the quality of patient care, yet the isolated sonographic windows in the most advanced prototypes can lead to inaccurate or error-prone measurements, and the safety and performance of these devices have not been thoroughly evaluated. Here we describe validation studies, conducted during daily activities at home, in the outpatient clinic, in the cardiac catheterization laboratory and in the intensive care unit, of the safety and performance of a wearable ultrasound sensor for blood pressure monitoring. The sensor has closely connected sonographic windows and a backing layer that improves the sensor's accuracy and reliability to meet the highest requirements of clinical standards. The validation results support the clinical use of the sensor.
Large DNA deletions occur during DNA repair at 20-fold lower frequency for base editors and prime editors than for Cas9 nucleases
Hwang GH, Lee SH, Oh M, Kim S, Habib O, Jang HK, Kim HS, Kim Y, Kim CH, Kim S and Bae S
When used to edit genomes, Cas9 nucleases produce targeted double-strand breaks in DNA. Subsequent DNA-repair pathways can induce large genomic deletions (larger than 100 bp), which constrains the applicability of genome editing. Here we show that Cas9-mediated double-strand breaks induce large deletions at varying frequencies in cancer cell lines, human embryonic stem cells and human primary T cells, and that most deletions are produced by two repair pathways: end resection and DNA-polymerase theta-mediated end joining. These findings required the optimization of long-range amplicon sequencing, the development of a k-mer alignment algorithm for the simultaneous analysis of large DNA deletions and small DNA alterations, and the use of CRISPR-interference screening. Despite leveraging mutated Cas9 nickases that produce single-strand breaks, base editors and prime editors also generated large deletions, yet at approximately 20-fold lower frequency than Cas9. We provide strategies for the mitigation of such deletions.
Solvent-mediated analgesia via the suppression of water permeation through TRPV1 ion channels
Liu Y, He Y, Tong J, Guo S, Zhang X, Luo Z, Sun L, Chang C, Zhuang B and Liu X
Activation of the ion channel transient receptor potential vanilloid 1 (TRPV1), which is integral to pain perception, leads to an expansion of channel width, facilitating the passage of cations and large organic molecules. However, the permeability of TRPV1 channels to water remains uncertain, owing to a lack of suitable tools to study water dynamics. Here, using upconversion nanophosphors to discriminate between HO and DO, by monitoring water permeability across activated TRPV1 at the single-cell and single-molecule levels, and by combining single-channel current measurements with molecular dynamics simulations, we show that water molecules flow through TRPV1 and reveal a direct connection between water migration, cation flow and TRPV1 functionality. We also show in mouse models of acute or chronic inflammatory pain that the administration of deuterated water suppresses TRPV1 activity, interrupts the transmission of pain signals and mitigates pain without impacting other neurological responses. Solvent-mediated analgesia may inspire alternative options for pain management.
Systemically injected oxygen within rapidly dissolving microbubbles improves the outcomes of severe hypoxaemia in swine
Mancebo JG, Sack K, Hartford J, Dominguez S, Balcarcel-Monzon M, Chartier E, Nguyen T, Cole AR, Sperotto F, Harrild DM, Polizzotti BD, Everett AD, Packard AB, Dearling J, Nedder AG, Warfield S, Yang E, Lidov HGW, Kheir JN and Peng Y
Acute respiratory failure can cause profound hypoxaemia that leads to organ injury or death within minutes. When conventional interventions are ineffective, the intravenous administration of oxygen can rescue patients from severe hypoxaemia, but at the risk of microvascular obstruction and of toxicity of the carrier material. Here we describe polymeric microbubbles as carriers of high volumes of oxygen (350-500 ml of oxygen per litre of foam) that are stable in storage yet quickly dissolve following intravenous injection, reverting to their soluble and excretable molecular constituents. In swine with profound hypoxaemia owing to acute and temporary (12 min) upper-airway obstruction, the microbubble-mediated delivery of oxygen led to: the maintenance of critical oxygenation, lowered burdens of cardiac arrest, improved survival, and substantially improved neurologic and kidney function in surviving animals. Our findings underscore the importance of maintaining a critical threshold of oxygenation and the promise of injectable oxygen as a viable therapy in acute and temporary hypoxaemic crises.
Downregulating human leucocyte antigens on mesenchymal stromal cells by epigenetically repressing a β-microglobulin super-enhancer
Wang F, Li R, Xu JY, Bai X, Wang Y, Chen XR, Pan C, Chen S, Zhou K, Heng BC, Wu X, Guo W, Song Z, Jin SC, Zhou J, Zou XH, Ouyang HW and Liu H
Immune rejection caused by mismatches in human leucocyte antigens (HLAs) remains a major obstacle to the success of allogeneic cell therapies. Current strategies for the generation of 'universal' immune-compatible cells, particularly the editing of HLA class I (HLA-I) genes or the modulation of proteins that inhibit natural killer cells, often result in genomic instability or cellular cytotoxicity. Here we show that a β-microglobulin super-enhancer (B2M-SE) that is responsive to interferon-γ is a critical regulator of the expression of HLA-I on mesenchymal stromal cells (MSCs). Targeted epigenetic repression of B2M-SE in MSCs reduced the surface expression of HLA-I below the threshold required to activate allogenic T cells while maintaining levels sufficient to evade cytotoxicity mediated by natural killer cells. In a humanized mouse model, the epigenetically edited MSCs demonstrated improved survival by evading the immune system, allowing them to exert enhanced therapeutic effects on LPS-induced acute lung injury. Targeted epigenetic repression of B2M-SE may facilitate the development of off-the-shelf cell sources for allogeneic cell therapy.
Overcoming immune hurdles to implant longevity
Computational design of protein binders that boost the antitumour efficacy of CAR T cells
Immunogenic amines on lipid nanoparticles
Sharma P, Breier D and Peer D
Viscoelastic synthetic antigen-presenting cells for augmenting the potency of cancer therapies
Liu Z, Li YR, Yang Y, Zhu Y, Yuan W, Hoffman T, Wu Y, Zhu E, Zarubova J, Shen J, Nan H, Yeh KW, Hasani-Sadrabadi MM, Zhu Y, Fang Y, Ge X, Li Z, Soto J, Hsiai T, Yang L and Li S
The use of synthetic antigen-presenting cells to activate and expand engineered T cells for the treatment of cancers typically results in therapies that are suboptimal in effectiveness and durability. Here we describe a high-throughput microfluidic system for the fabrication of synthetic cells mimicking the viscoelastic and T-cell-activation properties of antigen-presenting cells. Compared with rigid or elastic microspheres, the synthetic viscoelastic T-cell-activating cells (SynVACs) led to substantial enhancements in the expansion of human CD8 T cells and to the suppression of the formation of regulatory T cells. Notably, activating and expanding chimaeric antigen receptor (CAR) T cells with SynVACs led to a CAR-transduction efficiency of approximately 90% and to substantial increases in T memory stem cells. The engineered CAR T cells eliminated tumour cells in a mouse model of human lymphoma, suppressed tumour growth in mice with human ovarian cancer xenografts, persisted for longer periods and reduced tumour-recurrence risk. Our findings underscore the crucial roles of viscoelasticity in T-cell engineering and highlight the utility of SynVACs in cancer therapy.
All-optical optoacoustics for clinical diagnostics
Deán-Ben XL
Expanded toolkits for RNA circularization
Wang X, Huang Y and Chen LL
Ultrabright and ultrafast afterglow imaging in vivo via nanoparticles made of trianthracene derivatives
Wang Y, Guo J, Chen M, Liao S, Xu L, Chen Q, Song G and Zhang XB
Low sensitivity, photobleaching, high-power excitation and long acquisition times constrain the utility of afterglow luminescence. Here we report the design and imaging performance of nanoparticles made of electron-rich trianthracene derivatives that, on excitation by room light at ultralow power (58 μW cm), emit afterglow luminescence at ~500 times those of commonly used organic afterglow nanoparticles. The nanoparticles' ultrabright afterglow allowed for deep-tissue imaging (up to 6 cm), for ultrafast afterglow imaging (at short acquisition times down to 0.01 s) of naturally behaving mice with negligible photobleaching, even after re-excitation for over 15 cycles, and for the accurate visualization of subcutaneous and orthotopic tumours and of plaque in carotid arteries. We also show that an afterglow nanoparticle that is activated only in the presence of granzyme B allowed for the tracking of granzyme-B activity in the context of therapeutic monitoring. The high sensitivity and negligible photobleaching of the organic afterglow nanoparticles offer advantages for real-time in vivo monitoring of physiopathological processes.
Spatially resolved subcellular protein-protein interactomics in drug-perturbed lung-cancer cultures and tissues
Cai S, Hu T, Venkataraman A, Rivera Moctezuma FG, Ozturk E, Zhang N, Wang M, Zvidzai T, Das S, Pillai A, Schneider F, Ramalingam SS, Oh YT, Sun SY and Coskun AF
Protein-protein interactions (PPIs) regulate signalling pathways and cell phenotypes, and the visualization of spatially resolved dynamics of PPIs would thus shed light on the activation and crosstalk of signalling networks. Here we report a method that leverages a sequential proximity ligation assay for the multiplexed profiling of PPIs with up to 47 proteins involved in multisignalling crosstalk pathways. We applied the method, followed by conventional immunofluorescence, to cell cultures and tissues of non-small-cell lung cancers with a mutated epidermal growth-factor receptor to determine the co-localization of PPIs in subcellular volumes and to reconstruct changes in the subcellular distributions of PPIs in response to perturbations by the tyrosine kinase inhibitor osimertinib. We also show that a graph convolutional network encoding spatially resolved PPIs can accurately predict the cell-treatment status of single cells. Multiplexed proximity ligation assays aided by graph-based deep learning can provide insights into the subcellular organization of PPIs towards the design of drugs for targeting the protein interactome.