Publications

2024
Pearce S, Lin C, Pérez-Mercader J. Adaptive and Dissipative Hierarchical Population Crowding of Synthetic Protocells through Click-PISA under Gradient Energy Inputs. Nano Letters. 2024;24 (8) :2457–2464. Publisher's VersionAbstract
The ability of living objects to respond rapidly en masse to various stimuli or stress is an important function in response to externally applied changes in the local environment. This occurs across many length scales, for instance, bacteria swarming in response to different stimuli or stress and macromolecular crowding within cells. Currently there are few mechanisms to induce similar autonomous behaviors within populations of synthetic protocells. Herein, we report a system in which populations of individual objects behave in a coordinated manner in response to changes in the energetic environment by the emergent self-organization of large object swarms. These swarms contain protocell populations of approximately 60 000 individuals. We demonstrate the dissipative nature of the hierarchical constructs, which persist under appropriate UV stimulation. Finally, we identify the ability of the object populations to change behaviors in an adaptive population-wide response to the local energetic environment.
Kingsley EP, Hager ER, Lassance J-M, Turner KM, Harringmeyer OS, Kirby C, Neugeboren BI, Hoekstra HE. Adaptive tail-length evolution in deer mice is associated with differential Hoxd13 expression in early development. Nature Ecology & Evolution. 2024 :1–15. Publisher's VersionAbstract
Variation in the size and number of axial segments underlies much of the diversity in animal body plans. Here we investigate the evolutionary, genetic and developmental mechanisms driving tail-length differences between forest and prairie ecotypes of deer mice (Peromyscus maniculatus). We first show that long-tailed forest mice perform better in an arboreal locomotion assay, consistent with tails being important for balance during climbing. We then identify six genomic regions that contribute to differences in tail length, three of which associate with caudal vertebra length and the other three with vertebra number. For all six loci, the forest allele increases tail length, indicative of the cumulative effect of natural selection. Two of the genomic regions associated with variation in vertebra number contain Hox gene clusters. Of those, we find an allele-specific decrease in Hoxd13 expression in the embryonic tail bud of long-tailed forest mice, consistent with its role in axial elongation. Additionally, we find that forest embryos have more presomitic mesoderm than prairie embryos and that this correlates with an increase in the number of neuromesodermal progenitors, which are modulated by Hox13 paralogues. Together, these results suggest a role for Hoxd13 in the development of natural variation in adaptive morphology on a microevolutionary timescale.
Kapate N, Liao R, Sodemann RL, Stinson T, Prakash S, Kumbhojkar N, Suja VC, Wang LL-W, Flanz M, Rajeev R, et al. Backpack-mediated anti-inflammatory macrophage cell therapy for the treatment of traumatic brain injury. PNAS Nexus. 2024;3 (1) :pgad434. Publisher's VersionAbstract
Traumatic brain injury (TBI) is a debilitating disease with no current therapies outside of acute clinical management. While acute, controlled inflammation is important for debris clearance and regeneration after injury, chronic, rampant inflammation plays a significant adverse role in the pathophysiology of secondary brain injury. Immune cell therapies hold unique therapeutic potential for inflammation modulation, due to their active sensing and migration abilities. Macrophages are particularly suited for this task, given the role of macrophages and microglia in the dysregulated inflammatory response after TBI. However, maintaining adoptively transferred macrophages in an anti-inflammatory, wound-healing phenotype against the proinflammatory TBI milieu is essential. To achieve this, we developed discoidal microparticles, termed backpacks, encapsulating anti-inflammatory interleukin-4, and dexamethasone for ex vivo macrophage attachment. Backpacks durably adhered to the surface of macrophages without internalization and maintained an anti-inflammatory phenotype of the carrier macrophage through 7 days in vitro. Backpack–macrophage therapy was scaled up and safely infused into piglets in a cortical impact TBI model. Backpack–macrophages migrated to the brain lesion site and reduced proinflammatory activation of microglia in the lesion penumbra of the rostral gyrus of the cortex and decreased serum concentrations of proinflammatory biomarkers. These immunomodulatory effects elicited a 56% decrease in lesion volume. The results reported here demonstrate, to the best of our knowledge, a potential use of a cell therapy intervention for a large animal model of TBI and highlight the potential of macrophage-based therapy. Further investigation is required to elucidate the neuroprotection mechanisms associated with anti-inflammatory macrophage therapy.
2023
Zhang A, Zwang TJ, Lieber CM. Biochemically functionalized probes for cell-type–specific targeting and recording in the brain. Science Advances. 2023;9 (48) :eadk1050. Publisher's VersionAbstract
Selective targeting and modulation of distinct cell types and neuron subtypes is central to understanding complex neural circuitry and could enable electronic treatments that target specific circuits while minimizing off-target effects. However, current brain-implantable electronics have not yet achieved cell-type specificity. We address this challenge by functionalizing flexible mesh electronic probes, which elicit minimal immune response, with antibodies or peptides to target specific cell markers. Histology studies reveal selective association of targeted neurons, astrocytes, and microglia with functionalized probe surfaces without accumulating off-target cells. In vivo chronic electrophysiology further yields recordings consistent with selective targeting of these cell types. Last, probes functionalized to target dopamine receptor 2 expressing neurons show the potential for neuron-subtype–specific targeting and electrophysiology.
Ahrendsen JT, Nong Y, Huo Y, Steele J, Anderson MP. CD8 cytotoxic T-cell infiltrates and cellular damage in the hypothalamus in human obesity. Acta Neuropathol Commun. 2023;11 (1) :163. Publisher's VersionAbstract
Rare cases of paraneoplastic obesity in children suggest sporadic obesity might also arise from an adaptive immune cell-mediated mechanism. Since the hypothalamus is a central regulator of feeding behavior and energy expenditure, we quantified lymphocytic inflammation in this region in a cohort of obese and non-obese human post-mortem brains. We report that CD8-positive cytotoxic T-cells are increased in hypothalamic median eminence/arcuate nucleus (ME/Arc) and bed nucleus of the stria terminalis in 40% of obese compared to non-obese patients, but not in other hypothalamic nuclei or brain regions. CD8 T-cells were most abundant in individuals with concurrent obesity and diabetes. Markers of cytotoxic T-cell induced damage, activated caspase 3 and poly-ADP ribose, were also elevated in the ME/Arc of obese patients. To provoke CD8 cytotoxic T-cell infiltrates in ventromedial region of hypothalamus in mice we performed stereotactic injections of an adeno-associated virus expressing immunogenic green fluorescent protein or saline. AAV but not saline injections triggered hypothalamic CD8 T-cell infiltrates associated with a rapid weight gain in mice recapitulating the findings in human obesity. This is the first description of the neuropathology of human obesity and when combined with its reconstitution in a mouse model suggests adaptive immunity may drive as much as 40% of the human condition.
Mizes KGC, Lindsey J, Escola GS, Olveczky BP. Dissociating the contributions of sensorimotor striatum to automatic and visually guided motor sequences. Nat Neurosci. 2023;26 (10) :1791-1804. Publisher's VersionAbstract
The ability to sequence movements in response to new task demands enables rich and adaptive behavior. However, such flexibility is computationally costly and can result in halting performances. Practicing the same motor sequence repeatedly can render its execution precise, fast and effortless, that is, 'automatic'. The basal ganglia are thought to underlie both types of sequence execution, yet whether and how their contributions differ is unclear. We parse this in rats trained to perform the same motor sequence instructed by cues and in a self-initiated overtrained, or 'automatic,' condition. Neural recordings in the sensorimotor striatum revealed a kinematic code independent of the execution mode. Although lesions reduced the movement speed and affected detailed kinematics similarly, they disrupted high-level sequence structure for automatic, but not visually guided, behaviors. These results suggest that the basal ganglia are essential for 'automatic' motor skills that are defined in terms of continuous kinematics, but can be dispensable for discrete motor sequences guided by sensory cues.
Adebowale K, Guerriero JL, Mitragotri S. Dynamics of macrophage tumor infiltration. Applied Physics Reviews. 2023;10 (4). Publisher's VersionAbstract
Long-term remission in cancer patients treated with ex vivo bona fide M1-induced macrophages has been poor, and the reasons behind this are not understood. Injected M1 macrophages must physically migrate to tumors to execute their role that leads to a therapeutic benefit. However, the trafficking of macrophages to tumors has not been rigorously studied. We hypothesized that trafficking capabilities of macrophages are impacted when naive M0 macrophages are converted into an M1 phenotype for macrophage therapy. To test this, we developed a three-dimensional assay comprising a tumor spheroid and macrophages to quantify macrophage tumor transport. Cell migration, permeability, and kinetics of tumor entry were quantitatively defined and compared between macrophage phenotypes. Our results demonstrate that compared to M0 macrophages, M1 macrophages migrate less efficiently toward the tumor spheroid and exhibit a fivefold lower tumor permeability. Live imaging data combined with unsupervised machine learning algorithms reveal that macrophage migration correlates with their shape transitions. Our studies highlight the importance of transport considerations in determining the efficacy of cell therapies. This study quantitatively demonstrates that the transport properties of macrophages in tumors depend on their phenotype.
Yang X, Qi Y, Wang C, Zwang TJ, Rommelfanger NJ, Hong G, Lieber CM. Laminin-coated electronic scaffolds with vascular topography for tracking and promoting the migration of brain cells after injury. Nat Biomed Eng. 2023;7 (10) :1282-1292. Publisher's VersionAbstract
In the adult brain, neural stem cells are largely restricted into spatially discrete neurogenic niches, and hence areas of neuron loss during neurodegenerative disease or following a stroke or traumatic brain injury do not typically repopulate spontaneously. Moreover, understanding neural activity accompanying the neural repair process is hindered by a lack of minimally invasive devices for the chronic measurement of the electrophysiological dynamics in damaged brain tissue. Here we show that 32 individually addressable platinum microelectrodes integrated into laminin-coated branched polymer scaffolds stereotaxically injected to span a hydrogel-filled cortical lesion and deeper regions in the brains of mice promote neural regeneration while allowing for the tracking of migrating host brain cells into the lesion. Chronic measurements of single-unit activity and neural-circuit analyses revealed the establishment of spiking activity in new neurons in the lesion and their functional connections with neurons deeper in the brain. Electronic implants mimicking the topographical and surface properties of brain vasculature may aid the stimulation and tracking of neural-circuit restoration following injury.
Dingal P, Carte AN, Montague TG, Lim Suan, M. B. J, Schier AF. Molecular mechanisms controlling the biogenesis of the TGF-beta signal Vg1. Proc Natl Acad Sci U S A. 2023;120 (43) :e2307203120. Publisher's VersionAbstract
The TGF-beta signals Vg1 (Dvr1/Gdf3) and Nodal form heterodimers to induce vertebrate mesendoderm. The Vg1 proprotein is a monomer retained in the endoplasmic reticulum (ER) and is processed and secreted upon heterodimerization with Nodal, but the mechanisms underlying Vg1 biogenesis are largely elusive. Here, we clarify the mechanisms underlying Vg1 retention, processing, secretion, and signaling and introduce a Synthetic Processing (SynPro) system that enables the programmed cleavage of ER-resident and extracellular proteins. First, we find that Vg1 can be processed by intra- or extracellular proteases. Second, Vg1 can be processed without Nodal but requires Nodal for secretion and signaling. Third, Vg1-Nodal signaling activity requires Vg1 processing, whereas Nodal can remain unprocessed. Fourth, Vg1 employs exposed cysteines, glycosylated asparagines, and BiP chaperone-binding motifs for monomer retention in the ER. These observations suggest two mechanisms for rapid mesendoderm induction: Chaperone-binding motifs help store Vg1 as an inactive but ready-to-heterodimerize monomer in the ER, and the flexibility of Vg1 processing location allows efficient generation of active heterodimers both intra- and extracellularly. These results establish SynPro as an in vivo processing system and define molecular mechanisms and motifs that facilitate the generation of active TGF-beta heterodimers.
Lafuente-Gomez N, de Lazaro I, Dhanjani M, Garcia-Soriano D, Sobral MC, Salas G, Mooney DJ, Somoza A. Multifunctional magnetic nanoparticles elicit anti-tumor immunity in a mouse melanoma model. Mater Today Bio. 2023;23 :100817. Publisher's VersionAbstract
Immunotherapy has emerged as a promising strategy to eradicate cancer cells. Particularly, the development of cancer vaccines to induce a potent and sustained antigen-specific T cell response has become a center of attention. Herein, we describe a novel immunotherapy based on magnetic nanoparticles (MNP) covalently modified with the OVA(254-267) antigen and a CpG oligonucleotide via disulfide bonds. The MNP-CpG-COVA significantly enhances dendritic cell activation and CD8(+) T cell antitumoral response against B16-OVA melanoma cells in vitro. Notably, the immune response induced by the covalently modified MNP is more potent and sustained over time than that triggered by the free components, highlighting the advantage of nanoformulations in immunotherapies. What is more, the nanoparticles are stable in the blood after in vivo administration and induce potent levels of systemic tumor-specific effector CD8 + T cells. Overall, our findings highlight the potential of covalently functionalized MNP to induce robust immune responses against mouse melanoma.
Xiong T, Tarikere S, Rosser N, Li X, Yago M, Mallet J. A polygenic explanation for Haldane's rule in butterflies. Proc Natl Acad Sci U S A. 2023;120 (44) :e2300959120. Publisher's VersionAbstract
Two robust rules have been discovered about animal hybrids: Heterogametic hybrids are more unfit (Haldane's rule), and sex chromosomes are disproportionately involved in hybrid incompatibility (the large-X/Z effect). The exact mechanisms causing these rules in female heterogametic taxa such as butterflies are unknown but are suggested by theory to involve dominance on the sex chromosome. We investigate hybrid incompatibilities adhering to both rules in Papilio and Heliconius butterflies and show that dominance theory cannot explain our data. Instead, many defects coincide with unbalanced multilocus introgression between the Z chromosome and all autosomes. Our polygenic explanation predicts both rules because the imbalance is likely greater in heterogametic females, and the proportion of introgressed ancestry is more variable on the Z chromosome. We also show that mapping traits polygenic on a single chromosome in backcrosses can generate spurious large-effect QTLs. This mirage is caused by statistical linkage among polygenes that inflates estimated effect sizes. By controlling for statistical linkage, most incompatibility QTLs in our hybrid crosses are consistent with a polygenic basis. Since the two genera are very distantly related, polygenic hybrid incompatibilities are likely common in butterflies.
He LS, Qi Y, Allard CAH, Valencia-Montoya WA, Krueger SP, Weir K, Seminara A, Bellono NW. Molecular tuning of sea anemone stinging. Elife. 2023;12. Publisher's VersionAbstract
Jellyfish and sea anemones fire single-use, venom-covered barbs to immobilize prey or predators. We previously showed that the anemone Nematostella vectensis uses a specialized voltage-gated calcium (Ca(V)) channel to trigger stinging in response to synergistic prey-derived chemicals and touch (Weir et al., 2020). Here, we use experiments and theory to find that stinging behavior is suited to distinct ecological niches. We find that the burrowing anemone Nematostella uses uniquely strong Ca(V) inactivation for precise control of predatory stinging. In contrast, the related anemone Exaiptasia diaphana inhabits exposed environments to support photosynthetic endosymbionts. Consistent with its niche, Exaiptasia indiscriminately stings for defense and expresses a Ca(V) splice variant that confers weak inactivation. Chimeric analyses reveal that Ca(V)beta subunit adaptations regulate inactivation, suggesting an evolutionary tuning mechanism for stinging behavior. These findings demonstrate how functional specialization of ion channel structure contributes to distinct organismal behavior.
Kapate N, Dunne M, Kumbhojkar N, Prakash S, Wang LL, Graveline A, Park KS, Chandran Suja V, Goyal J, Clegg JR, et al. A backpack-based myeloid cell therapy for multiple sclerosis. Proc Natl Acad Sci U S A. 2023;120 (17) :e2221535120. Publisher's VersionAbstract
Multiple sclerosis (MS) is an incurable autoimmune disease and is currently treated by systemic immunosuppressants with off-target side effects. Although aberrant myeloid function is often observed in MS plaques in the central nervous system (CNS), the role of myeloid cells in therapeutic intervention is currently overlooked. Here, we developed a myeloid cell-based strategy to reduce the disease burden in experimental autoimmune encephalomyelitis (EAE), a mouse model of progressive MS. We developed monocyte-adhered microparticles ("backpacks") for activating myeloid cell phenotype to an anti-inflammatory state through localized interleukin-4 and dexamethasone signals. We demonstrate that backpack-laden monocytes infiltrated into the inflamed CNS and modulated both the local and systemic immune responses. Within the CNS, backpack-carrying monocytes regulated both the infiltrating and tissue-resident myeloid cell compartments in the spinal cord for functions related to antigen presentation and reactive species production. Treatment with backpack-monocytes also decreased the level of systemic pro-inflammatory cytokines. Additionally, backpack-laden monocytes induced modulatory effects on T(H)1 and T(H)17 populations in the spinal cord and blood, demonstrating cross talk between the myeloid and lymphoid arms of disease. Backpack-carrying monocytes conferred therapeutic benefit in EAE mice, as quantified by improved motor function. The use of backpack-laden monocytes offers an antigen-free, biomaterial-based approach to precisely tune cell phenotype in vivo, demonstrating the utility of myeloid cells as a therapeutic modality and target.
Salcedo MK, Jun BH, Socha JJ, Pierce NE, Vlachos PP, Combes SA. Complex hemolymph circulation patterns in grasshopper wings. Commun Biol. 2023;6 (1) :313. Publisher's VersionAbstract
An insect's living systems-circulation, respiration, and a branching nervous system-extend from the body into the wing. Wing hemolymph circulation is critical for hydrating tissues and supplying nutrients to living systems such as sensory organs across the wing. Despite the critical role of hemolymph circulation in maintaining healthy wing function, wings are often considered "lifeless" cuticle, and flows remain largely unquantified. High-speed fluorescent microscopy and particle tracking of hemolymph in the wings and body of the grasshopper Schistocerca americana revealed dynamic flow in every vein of the fore- and hindwings. The global system forms a circuit, but local flow behavior is complex, exhibiting three distinct types: pulsatile, aperiodic, and "leaky" flow. Thoracic wing hearts pull hemolymph from the wing at slower frequencies than the dorsal vessel; however, the velocity of returning hemolymph (in the hindwing) is faster than in that of the dorsal vessel. To characterize the wing's internal flow mechanics, we mapped dimensionless flow parameters across the wings, revealing viscous flow regimes. Wings sustain ecologically important insect behaviors such as pollination and migration. Analysis of the wing circulatory system provides a template for future studies investigating the critical hemodynamics necessary to sustaining wing health and insect flight.
Green DR, Winkler DE, Leichliter J, Harms GS, Hatt JM, Clauss M, Tutken T. Formation and Replacement of Bone And Tooth Mineralized Tissues in Green Iguanas (Iguana Iguana) Revealed by In-Vivo Fluorescence Marking. Integr Comp Biol. 2023. Publisher's VersionAbstract
Hard tissue formation patterns and rates reveal details of animal physiology, life history, and environment, but are understudied in reptiles. Here, we use fluorescence labels delivered in vivo and laser confocal scanning microscopy to study tooth and bone formation in a managed group of green iguanas (Iguana iguana, Linne 1758) kept for 1.5 years under experimentally controlled conditions and undergoing several dietary switches. We constrain rates of tooth elongation, which we observe to be slow when enamel is initially deposited (c. 9 microm/day), but then increases exponentially in the dentin root, reaching c. 55 microm/day or more after crown completion. We further constrain the total timing of tooth formation to approximately 40-60 days, and observe highly variable timings of tooth resorption onset and replacement. Fluorescent labels clearly indicate cohorts of teeth recruited within Zahnreihen replacement waves, with faster sequential tooth recruitment and greater wave sizes posteriorly, where each wave initiates. Rates of hard tissue formation in long bones range from 0.4-3.4 microm/day, correlating with animal weight gain, and cortical bone recording the entire history of the experiment. We suggest additional labeling experiments to study hard tissue formation patterns in other reptiles, and propose strategies for chemical analyses of hard tissues in order to extract temporal information about past environments, behaviors and diets from reptilian fossils throughout the Phanerozoic.
Nadler MJS, Chang W, Ozkaynak E, Huo Y, Nong Y, Boillot M, Johnson M, Moreno A, Matthew PA. Hominoid SVA-lncRNA AK057321 targets human-specific SVA retrotransposons in SCN8A and CDK5RAP2 to initiate neuronal maturation. Commun Biol. 2023;6 (1) :347. Publisher's VersionAbstract
SINE-VNTR-Alu (SVA) retrotransposons arose and expanded in the genome of hominoid primates concurrent with the slowing of brain maturation. We report genes with intronic SVA transposons are enriched for neurodevelopmental disease and transcribed into long non-coding SVA-lncRNAs. Human-specific SVAs in microcephaly CDK5RAP2 and epilepsy SCN8A gene introns repress their expression via transcription factor ZNF91 to delay neuronal maturation. Deleting the SVA in CDK5RAP2 initiates multi-dimensional and in SCN8A selective sodium current neuronal maturation by upregulating these genes. SVA-lncRNA AK057321 forms RNA:DNA heteroduplexes with the genomic SVAs and upregulates these genes to initiate neuronal maturation. SVA-lncRNA AK057321 also promotes species-specific cortex and cerebellum-enriched expression upregulating human genes with intronic SVAs (e.g., HTT, CHAF1B and KCNJ6) but not mouse orthologs. The diversity of neuronal genes with intronic SVAs suggest this hominoid-specific SVA transposon-based gene regulatory mechanism may act at multiple steps to specialize and achieve neoteny of the human brain.
Itoh Y, Sahni V, Shnider SJ, McKee H, Macklis JD. Inter-axonal molecular crosstalk via Lumican proteoglycan sculpts murine cervical corticospinal innervation by distinct subpopulations. Cell Rep. 2023;42 (3) :112182. Publisher's VersionAbstract
How CNS circuits sculpt their axonal arbors into spatially and functionally organized domains is not well understood. Segmental specificity of corticospinal connectivity is an exemplar for such regional specificity of many axon projections. Corticospinal neurons (CSN) innervate spinal and brainstem targets with segmental precision, controlling voluntary movement. Multiple molecularly distinct CSN subpopulations innervate the cervical cord for evolutionarily enhanced precision of forelimb movement. Evolutionarily newer CSN(BC-lat) exclusively innervate bulbar-cervical targets, while CSN(medial) are heterogeneous; distinct subpopulations extend axons to either bulbar-cervical or thoraco-lumbar segments. We identify that Lumican controls balance of cervical innervation between CSN(BC-lat) and CSN(medial) axons during development, which is maintained into maturity. Lumican, an extracellular proteoglycan expressed by CSN(BC-lat), non-cell-autonomously suppresses cervical collateralization by multiple CSN(medial) subpopulations. This inter-axonal molecular crosstalk between CSN subpopulations controls murine corticospinal circuitry refinement and forelimb dexterity. Such crosstalk is generalizable beyond the corticospinal system for evolutionary incorporation of new neuron populations into preexisting circuitry.
Carman CV, Nikova DN, Sakurai Y, Shi J, Novakovic VA, Rasmussen JT, Lam WA, Gilbert GE. Membrane curvature and PS localize coagulation proteins to filopodia and retraction fibers of endothelial cells. Blood Adv. 2023;7 (1) :60-72. Publisher's VersionAbstract
Prior reports indicate that the convex membrane curvature of phosphatidylserine (PS)-containing vesicles enhances formation of binding sites for factor Va and lactadherin. Yet, the relationship of convex curvature to localization of these proteins on cells remains unknown. We developed a membrane topology model, using phospholipid bilayers supported by nano-etched silica substrates, to further explore the relationship between curvature and localization of coagulation proteins. Ridge convexity corresponded to maximal curvature of physiologic membranes (radii of 10 or 30 nm) and the troughs had a variable concave curvature. The benchmark PS probe lactadherin exhibited strong differential binding to the ridges, on membranes with 4% to 15% PS. Factor Va, with a PS-binding motif homologous to lactadherin, also bound selectively to the ridges. Bound factor Va supported coincident binding of factor Xa, localizing prothrombinase complexes to the ridges. Endothelial cells responded to prothrombotic stressors and stimuli (staurosporine, tumor necrosis factor-alpha [TNF- alpha]) by retracting cell margins and forming filaments and filopodia. These had a high positive curvature similar to supported membrane ridges and selectively bound lactadherin. Likewise, the retraction filaments and filopodia bound factor Va and supported assembly of prothrombinase, whereas the cell body did not. The perfusion of plasma over TNF-alpha-stimulated endothelia in culture dishes and engineered 3-dimensional microvessels led to fibrin deposition at cell margins, inhibited by lactadherin, without clotting of bulk plasma. Our results indicate that stressed or stimulated endothelial cells support prothrombinase activity localized to convex topological features at cell margins. These findings may relate to perivascular fibrin deposition in sepsis and inflammation.
Reynolds DS, de Lazaro I, Blache ML, Liu Y, Jeffreys NC, Doolittle RM, Grandidier E, Olszewski J, Dacus MT, Mooney DJ, et al. Microporogen-Structured Collagen Matrices for Embedded Bioprinting of Tumor Models for Immuno-Oncology. Adv Mater. 2023 :e2210748. Publisher's VersionAbstract
Embedded bioprinting enables the rapid design and fabrication of complex tissues that recapitulate in vivo microenvironments. However, few biological matrices enable good print fidelity, while simultaneously facilitate cell viability, proliferation, and migration. Here, a new microporogen-structured (microPOROS) matrix for embedded bioprinting is introduced, in which matrix rheology, printing behavior, and porosity are tailored by adding sacrificial microparticles composed of a gelatin-chitosan complex to a prepolymer collagen solution. To demonstrate its utility, a 3D tumor model is created via embedded printing of a murine melanoma cell ink within the microPOROS collagen matrix at 4 degrees C. The collagen matrix is subsequently crosslinked around the microparticles upon warming to 21 degrees C, followed by their melting and removal at 37 degrees C. This process results in a microPOROS matrix with a fibrillar collagen type-I network akin to that observed in vivo. Printed tumor cells remain viable and proliferate, while antigen-specific cytotoxic T cells incorporated in the matrix migrate to the tumor site, where they induce cell death. The integration of the microPOROS matrix with embedded bioprinting opens new avenues for creating complex tissue microenvironments in vitro that may find widespread use in drug discovery, disease modeling, and tissue engineering for therapeutic use.
Spitzberg JD, Ferguson S, Yang KS, Peterson HM, Carlson JCT, Weissleder R. Multiplexed analysis of EV reveals specific biomarker composition with diagnostic impact. Nat Commun. 2023;14 (1) :1239. Publisher's VersionAbstract
Exosomes and extracellular vesicles (EV) are increasingly being explored as circulating biomarkers, but their heterogenous composition will likely mandate the development of multiplexed EV technologies. Iteratively multiplexed analyses of near single EVs have been challenging to implement beyond a few colors during spectral sensing. Here we developed a multiplexed analysis of EV technique (MASEV) to interrogate thousands of individual EVs during 5 cycles of multi-channel fluorescence staining for 15 EV biomarkers. Contrary to the common belief, we show that: several markers proposed to be ubiquitous are less prevalent than believed; multiple biomarkers concur in single vesicles but only in small fractions; affinity purification can lead to loss of rare EV subtypes; and deep profiling allows detailed analysis of EV, potentially improving the diagnostic content. These findings establish the potential of MASEV for uncovering fundamental EV biology and heterogeneity and increasing diagnostic specificity.

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