Biology subjects

Roukes, M. L.

Publications and source records attributed to Roukes, M. L..

6 recordsLinked to original sources

bioRxiv2026

Glucose selectively drives a rapid oxidative burst and immunometabolic reprogramming in human neutrophils during Mycobacterium tuberculosis infection

Neutrophil functions have been linked to tuberculosis (TB)-associated tissue damage; however, the mechanisms driving immunopathology in the human TB lung remain poorly understood, due partly to the scarcity of human tissue for study. Here, we examine the metabolic and bioenergetic reprogramming of human neutrophils in response to Mycobacterium tuberculosis (Mtb) infection. In human necrotic TB granulomas, levels of NETosis-associated proteins are increased and co-localize with GLUT3, linking nutrient uptake to tissue damage. In vitro, Mtb elicits an immediate, contact-dependent oxidative burst in human neutrophils, and the magnitude of this response is carbon source-dependent. Glucose enables the most robust responses, indicating that glucose metabolism is a key driver of neutrophil-mediated inflammatory damage during TB. Mtb-induced responses are distinct from those induced by PMA, non-tuberculous mycobacteria, or other pathogenic intracellular bacteria, and are mediated through multiple neutrophil surface receptors. Notably, our data show that while the oxidative burst is carbon source-dependent, cytokine production is not. Further, Mtb infection reprograms neutrophil metabolism from glycolysis to the pentose phosphate pathway (PPP), generating NADPH required for the oxidative burst. Inhibiting G6PD, NADPH oxidase, or PAD4 significantly reduces this response, highlighting the PPP as a promising host target for mitigating TB immunopathology.

microbiology↗

bioRxiv2025

Implantable CMOS Deep-Brain Fluorescence Imager with Single-Neuron Resolution

Despite the advantages of optical imaging over electrophysiology, such as cell-type specificity, its application has been limited to the investigation of shallow brain regions (< 2 mm) because of the light scattering property of brain tissue. Passive optical conduits such as graded-index lenses and waveguides have permitted access to deeper locales but with restricted resolution and field of view, while creating massive lesions along the inserted path, with little pathway to improvement in the technology. As an alternative, we present the Acus device, an active implantable complementary metal-oxide-semiconductor (CMOS) neural imager with a 512-pixel silicon image sensor post- processed into a 4.1-mm-long, 120-m-wide shank with a collinear fiber for illumination, which is able to record transient fluorescent signals in deep brain regions at 400 frames/sec. Acus can achieve single-neuron resolution in functional imaging of GCaMP6s-expressing neurons at a frame rate of 400 frames/sec.

neuroscience↗

bioRxiv2025

Molecularly-guided spatial proteomics captures single-cell identity and heterogeneity of the nervous system

Single-cell spatial proteomics (scSP) holds substantial potential for profiling healthy and diseased tissues. The emerging method of molecularly-guided unbiased scSP has mostly been applied to peripheral somatic tissues. Here, we optimize and apply scSP to the healthy and diseased mammalian brain, using molecularly-guided laser capture microdissection and unbiased mass spectrometry. We systematically evaluate the effects of tissue fixation, marker staining, and sample input size on proteome coverage and quantitative accuracy. We benchmark this workflow by profiling region-specific neuronal proteomes and describing the response of non-neuronal cells to acute brain injury. Across these applications, we integrate complementary transcriptomic resources to evaluate cross-modality trends and refine neuronal proteomic results by filtering out protein signals likely arising from non-neuronal cells, an essential consideration in heterogeneous tissues such as the brain. Finally, we leverage this approach to resolve proteomic differences between dopaminergic neuron subpopulations with differential vulnerability to Parkinsons disease and to uncover disease-specific disruptions in -synuclein-aggregate-bearing single dopaminergic neurons. Together, these data demonstrate the utility of scSP in neuroscience research for understanding fundamental biology and the molecular drivers of neurological conditions.

neuroscience↗

bioRxiv2020

Implantable photonic neural probes for light-sheet fluorescence brain imaging

SignificanceLight-sheet fluorescence microscopy is a powerful technique for high-speed volumetric functional imaging. However, in typical light-sheet microscopes, the illumination and collection optics impose significant constraints upon the imaging of non-transparent brain tissues. Here, we demonstrate that these constraints can be surmounted using a new class of implantable photonic neural probes. AimMass manufacturable, silicon-based light-sheet photonic neural probes can generate planar patterned illumination at arbitrary depths in brain tissues without any additional micro-optic components. ApproachWe develop implantable photonic neural probes that generate light sheets in tissue. The probes were fabricated in a photonics foundry on 200 mm diameter silicon wafers. The light sheets were characterized in fluorescein and in free space. The probe-enabled imaging approach was tested in fixed and in vitro mouse brain tissues. Imaging tests were also performed using fluorescent beads suspended in agarose. ResultsThe probes had 5 to 10 addressable sheets and average sheet thicknesses < 16 m for propagation distances up to 300 m in free space. Imaging areas were as large as {approx} 240 m x 490 m in brain tissue. Image contrast was enhanced relative to epifluorescence microscopy. ConclusionsThe neural probes can lead to new variants of light-sheet fluorescence microscopy for deep brain imaging and experiments in freely-moving animals.

bioengineering↗

bioRxiv2020

Signal separability in integrated neurophotonics

A new modality Photonic probes record fluorescent signals by using arrays of light emitters and detectors embedded in neural tissue. Neither the emitted nor collected light fields are focused. Instead, in proposed configurations, hundreds of emitters will form rapid sequences of structured illumination patterns--providing sufficient spatial and temporal differentiation of neural signals for computational demixing. Here we define criteria for evaluating probe designs for achieving better signal separability. We find that probe geometry has profound, often unintuitive, effects on the separability of neural signals, providing initial design guidelines to achieve separation of individual cells in densely labeled populations.

neuroscience↗

bioRxiv2018

Optogenetic manipulation of medullary neurons in the locust optic lobe

Locust is a widely used animal model for studying sensory processing and its relation to behavior. Due to the lack of genomic information, genetic tools to manipulate neural circuits in locusts are not yet available. We examined whether Semliki Forest virus is suitable to mediate exogenous gene expression in neurons of the locust optic lobe. We subcloned a channelrhodopsin variant and the yellow fluorescent protein Venus into a Semliki Forest virus vector and injected the virus into the optic lobe of locusts (Schistocerca americana). Fluorescence was observed in all injected optic lobes. Most neurons that expressed the recombinant proteins were located in the first two neuropils of the optic lobe, the lamina and medulla. Extracellular recordings demonstrated that laser illumination increased the firing rate of medullary neurons expressing channelrhodopsin. The optogenetic activation of the medullary neurons also triggered firing of a postsynaptic, looming-sensitive neuron, the Lobula Giant Movement Detector (LGMD). These results indicate that Semliki Forest virus is efficient at mediating transient exogenous gene expression and provides a tool to manipulate neural circuits in the locust nervous system and likely other insects.\n\nNew and NoteworthyUsing Semliki Forest virus, we efficiently delivered channelrhodopsin into neurons of the locust optic lobe. We demonstrate that laser illumination increases the firing of the medullary neurons expressing channelrhodopsin and of an identified postsynaptic target neuron, the LGMD neuron. This technique allows to manipulate the neuronal activity in locust neural circuits using optogenetics.

neuroscience↗