Biology subjects

Lo, H.

Publications and source records attributed to Lo, H..

11 recordsLinked to original sources

bioRxiv2026

Defensive lipid droplets are PUFA reservoirs driving bacterial clearance and inflammation

Lipid droplets (LDs) rapidly form in infected cells to participate in the defence against microbes. Here, we investigate the involvement of LD lipids in these immune responses. Comparative shotgun and targeted lipidomics demonstrate that in vivo host LDs accumulate polyunsaturated fatty acids (PUFAs). PUFAs arrive at cells from the bloodstream to be further metabolised into complex PUFAs accrued by LD-triglycerides and -phospholipids. Host lipid metabolism is transcriptionally controlled by rapid, transient, and intricate immune programs initiated by pathogen-associated molecular patterns and relayed by cytokines such as interferons (type I and II), interleukins (IL-1{beta}), and tumour necrosis factor. When this lipid and signalling environment is reproduced in cultured macrophages, newly formed LDs accumulate defensive proteins, coordinate the synthesis of complex PUFAs, and become PUFA reservoirs and suppliers. Among LD-PUFAs, the {omega}-6 arachidonic acid is the most actively metabolised during the initial phases of innate immunity. Released from LDs by adipose triglyceride lipase, arachidonic acid is used by macrophages for prostaglandin synthesis, bacterial phagocytosis, and elimination of microbes. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=163 HEIGHT=200 SRC="FIGDIR/small/711356v2_ufig1.gif" ALT="Figure 1"> View larger version (107K): org.highwire.dtl.DTLVardef@14d65eorg.highwire.dtl.DTLVardef@5ecc1org.highwire.dtl.DTLVardef@fa99e5org.highwire.dtl.DTLVardef@8d9632_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2026

Microalgal Co-Cultivation meets Media Recycling: A Circular Pathway to Serum and Amino-Acid Reduction in Cultivated Meat

Our increasing global population combined with the UN Sustainable Development Goals of zero hunger and good health require greater protein intake per capita and higher protein production. Consequently, sustainable food alternatives such as cultivated meat (CM) are urgently required. However, large-scale CM cell-systems face key challenges, particularly high media costs driven by amino acids and the need for ethically-sourced growth factors. Microalgae offer promising solutions, producing high protein yields with all essential amino acids simply from light, CO2, water and nutrients or spent CM media. Here we present Chlorella BDH-1 grown in spent CM media waste as a substitute-source for reduced amino acids and fetal bovine serum in cell culture media, enabling a circular strategy through beneficial mammalian cell-algae co-cultivation. We identified optimal algal growth conditions for maximum protein yield and demonstrated that two recycling rounds using industry-derived spent CM media maximize microalgal biomass yield per unit volume of waste media. We obtained algal lysate, determined thermal processing as the most cost-effective and mammalian cell-beneficial approach, and identified consumed lysate components. Compared to standard media, our lysate increased mammalian cell proliferation over 2-fold in reduced serum and amino acid conditions, replacing costly cell media components. We finally closed the loop by demonstrating a synergistic effect of the algal lysate with our co-cultivation - which co-produces algal biomass. The combination boosted mammalian cell proliferation 1.45-fold, conservatively estimating a media cost reduction by [~]66%. These findings establish parameters to advance the field towards cost-effective sustainable circular cell culture systems with applications in CM production and other biotechnology fields requiring large-scale tissue culture. Technology Readiness:

bioengineering↗

bioRxiv2025

A Standardized Protocol to Investigate Trans-Endothelial Trafficking in Zebrafish: Nano-bio Interactions of PEG-based Nanoparticles in Live Vasculature

Trans-endothelial transport of nanoparticles remains poorly characterized in live organisms. The zebrafish is a well-established model for direct in vivo imaging; however, standardized controls are not consistently applied across studies. Here, we developed a standardized protocol to assess nanoparticle trans-endothelial trafficking in live zebrafish. We tested a range of tracers and identified 2000 kDa dextran as an optimal control for standardizing microinjections and quantifying nanoparticle transport in a systematic unbiased manner. As validation, we identified the early physiological trans-endothelial transport pathways in zebrafish embryos using 40 kDa dextran as a nanoparticle surrogate. Using our workflow, we assessed the extravasation of 3, 7, 32 and 47 nm polyethylene glycol (PEG)-based nanoparticles. Using cAMP stimulation to restrict paracellular routes, and inhibitors to impede dynamin-dependent endocytosis, we demonstrated that PEG-based hyperbranched polymer (HBP) nanoparticles of 3 to 7 nm traverse the endothelial barrier via paracellular routes and 32 and 47 nm PEG micelles adopt dynamin- dependent endocytic trafficking over paracellular transport. We characterized the emergence of caveolae in the vasculature up to 17 days post-fertilization (dpf) using a cavin1b knock-in zebrafish line. Using cavin1a/cavin1b double knockout (DKO) zebrafish, and tumor-bearing Cavin-1 null mice, we showed that caveolae do not contribute to the transvascular transport of these PEG-based nanoparticles. This work highlights the rigour of the standardized protocol for assessing nanoparticle trans-endothelial transport in the live zebrafish, providing a systematic approach for quantification using a standardized control.

cell biology↗

bioRxiv2025

New glucose-abstaining Chlorella algae doubles mammalian cell culture longevity, boosts performance and drops serum needs enabling scaled applications.

Mammalian cell culture technologies are crucial for recombinant protein production, organoid generation, medical applications, and the generation of in vitro cultivated meat. However, they are limited by high costs, vascular O2 provision, and the resultant inhibition of 3D tissue formation. Effective media usage along with oxygenation and waste management to extend culture health and longevity are key to improving all three. Microalgae, utilizing organic or inorganic CO2, produce O2 from light which complements oxygen-consuming and CO2-respiring mammalian cells and tissue culture. However, common microalgal cultivation conditions differ in temperature and salinity from mammalian cell cultivation environments, making co-cultivation short-lived and challenging. We screened several different microalgae species to identify locally isolated Chlorella BDH-1 as candidate that has high growth rates in mammalian culture conditions while, unlike other Chlorella species, does not compete for glucose as an energy source. In mammalian cell co-culture, BDH1 reduces cellular waste products, stabilizes pH, doubles culture longevity, increases growth performance up to 80%, and reduces expensive and ethically challenging foetal bovine serum requirements. Chlorella BDH-1 was also non-inflammatory and tolerant of clinical antibiotics. Collectively, mammalian cell/BDH1 co-cultivation improves tissue culture health and reduces costs, paving the path for applications in the biotechnology and medical sectors.

cell biology↗

bioRxiv2024

Unsaturated lipids as key control points for caveola formation and disassembly

Caveolae are specialized plasma membrane domains with a unique lipid composition. Recent work has implicated lipid peroxidation in triggering caveola disassembly, releasing caveolar proteins to regulate the cellular response to oxidative stress. Here we investigated the role of specific lipid species in caveola formation and response to oxidative stress. Systematic screening of lipid enzymes identified ACSL4, a critical enzyme in the synthesis of polyunsaturated fatty acid-containing lipids, and enzymes involved in the biosynthesis of pro-ferroptotic ether lipids, as key regulators of caveola formation. Omega-6 fatty acids promoted efficient caveola formation, while their oxidation or displacement by omega-3 or monounsaturated fatty acids disrupted this process. Moreover, we found that omega-6 fatty acid-containing membrane lipids were required for oxidative stress-induced caveola disassembly. These findings unveil a new model for caveola formation, highlighting specific unsaturated lipids as essential caveolar components and key control points for caveola disassembly in response to an oxidizing environment.

cell biology↗

bioRxiv2023

Integrated spatial protein and RNA analysis on the same section using MICS technology

Spatial Biology has evolved from the molecular characterization of microdissected cells to high throughput spatial RNA and protein expression analysis at scale. The main limitation of spatial technologies so far is the inability to resolve protein and RNA information in the same histological section. Here, we report for the first time the integration of highly multiplexed RNA and protein detection on the same tissue section. We developed a new, automated, spatial RNA detection method (RNAsky), which is based on targeted rolling circle amplification and iterative staining. We combine RNAsky with MACSima Imaging Cyclic Staining (MICS) based protein analysis and show compatibility with subsequent standard hematoxylin and eosin (H&E) staining. Using both, open-source tools and our recently developed software suite MACS(R) iQ View, we demonstrate our multiomics MICS workflow by characterizing key immune-oncology markers at subcellular resolution across normal and diseased tissues.

molecular biology↗

bioRxiv2023

Binge Feeding Promotes Appetite via Modulating Olfactory Flavor Representation

Binge eating commonly leads to overeating, but the exact mechanism is unclear. While it is known that experiencing flavor contributes to satiety, the interactions between flavor, feeding rate, and food intake remain unknown. Here, we demonstrate a novel feeding rate-dependent feedback loop between olfactory flavor representation in the anterior olfactory (piriform) cortex (aPC) and food intake. Using miniscopes for in vivo calcium imaging in freely foraging mice, we identified specific excitatory neuronal responses to food and water during slow feeding. Switching to binge feeding transformed these specific responses into unspecific global suppression of neuronal activity. Food consumption was predicted by the degree of suppression of neuronal activity in the aPC during binge feeding. Also, food deprivation enhanced neuronal activity suppression. We confirmed the hypothesis that aPC suppression promotes food intake with closed-loop optogenetics experiments. Together, we show that olfactory sensory representation in the aPC reciprocally interacts with consummatory behavior to enhance food intake.

neuroscience↗

bioRxiv2021

Caveolae, CAVIN1, and lipid peroxidation mediate the oxidative stress response

Caveolae have been linked to many biological functions, but their precise roles are unclear. Using quantitative whole cell proteomics of genome-edited cells, we show that the oxidative stress response is the major pathway dysregulated in cells lacking the key caveola structural protein, CAVIN1. CAVIN1 deletion compromised sensitivity to oxidative stress in cultured cells and in animals. Wound-induced accumulation of reactive oxygen species and apoptosis were suppressed in Cavin1-null zebrafish, negatively affecting regeneration. Oxidative stress triggered lipid peroxidation and induced caveolar disassembly. The resulting release of CAVIN1 from caveolae allowed direct interaction between CAVIN1 and NRF2, a key regulator of the antioxidant response, facilitating NRF2 degradation. CAVIN1-null cells with impaired negative regulation of NRF2 showed resistance to lipid peroxidation-induced ferroptosis. Thus, caveolae, via lipid peroxidation and CAVIN1 release, maintain cellular susceptibility to oxidative stress-induced cell death demonstrating a crucial role for this enigmatic organelle in cellular homeostasis and wound response.

cell biology↗

bioRxiv2021

Muscle-specific Cavin4 interacts with Bin1 to promote T-tubule formation and stability in developing skeletal muscle

The cavin proteins are essential for caveola biogenesis and function. Here, we identify a role for the muscle-specific component, Cavin4, in skeletal muscle T-tubule development by analyzing two vertebrate systems: mouse and zebrafish. In both models Cavin4 localized to T-tubules and loss of Cavin4 resulted in aberrant T-tubule maturation. In zebrafish, which possess duplicated cavin4 paralogs, Cavin4b was shown to directly interact with the T-tubule-associated BAR domain protein, Bin1. Loss of both Cavin4a and Cavin4b caused aberrant accumulation of interconnected caveolae within the T-tubules, a fragmented T-tubule network enriched in Caveolin-3, and an impaired Ca2+ response upon mechanical stimulation. We propose a role for Cavin4 in remodeling the T-tubule membrane early in development by recycling caveolar components from the T-tubule to the sarcolemma. This generates a stable T-tubule domain lacking caveolae that is essential for T-tubule function.

cell biology↗

bioRxiv2020

Creating Clear and Informative Image-based Figures for Scientific Publications

Scientists routinely use images to display data. Readers often examine figures first; therefore, it is important that figures are accessible to a broad audience. Many resources discuss fraudulent image manipulation and technical specifications for image acquisition; however, data on the legibility and interpretability of images are scarce. We systematically examined these factors in non-blot images published in the top 15 journals in three fields; plant sciences, cell biology and physiology (n=580 papers). Common problems included missing scale bars, misplaced or poorly marked insets, images or labels that were not accessible to colorblind readers, and insufficient explanations of colors, labels, annotations, or the species and tissue or object depicted in the image. Papers that met all good practice criteria examined for all image-based figures were uncommon (physiology 16%, cell biology 12%, plant sciences 2%). We present detailed descriptions and visual examples to help scientists avoid common pitfalls when publishing images. Our recommendations address image magnification, scale information, insets, annotation, and color and may encourage discussion about quality standards for bioimage publishing.

bioinformatics↗

bioRxiv2019

Circuit-specific dendritic development in the piriform cortex

Dendritic geometry is largely determined during postnatal development and has a substantial impact on neural function. In sensory processing, postnatal development of the dendritic tree is affected by two dominant circuit motifs, ascending sensory feedforward inputs and descending and local recurrent connections. In the three-layered anterior piriform cortex, neurons in the sublayers 2a and 2b display vertical segregation of these two circuit motifs. Here, we combined electrophysiology, detailed morphometry and Ca2+ imaging in acute mouse brain slices and modeling to study circuit specific aspects of dendritic development. We observed that determination of branching complexity, dendritic length increases and pruning occurred in distinct developmental phases. Layer 2a and layer 2b neurons displayed developmental phase specific differences between their apical and basal dendritic trees related to differences in circuit incorporation. We further identified functional candidate mechanisms for circuit-specific differences in postnatal dendritic growth in sublayers 2a and 2b at the meso- and microscale level. Already in the first postnatal week, functional connectivity of layer 2a and layer 2b neurons during early spontaneous network activity scales with differences in basal dendritic growth. During the early critical period of sensory plasticity in the piriform cortex, our data is consistent with a model that proposes a role for dendritic NMDA-spikes in selecting branches for survival during developmental pruning in apical dendrites. The different stages of the morphological and functional developmental pattern differences between layer 2a and layer 2b neurons demonstrate the complex interplay between dendritic development and circuit specificity. Significance StatementSensory cortices are composed of ascending sensory circuits that relay sensory information from the periphery and recurrent intracortical circuits. Dendritic trees of neurons are shaped during development and determine which circuits contribute to the neuronal input space. To date, circuit-specific aspects of dendritic development and the underlying mechanisms are poorly understood. Here, we investigate dendritic development in layer 2 of the piriform cortex, a three-layered palaeocortex that displays a clear vertical segregation of sensory and recurrent circuits. Our results suggest that dendritic development occurs in distinct developmental phases with different circuit-specific properties. We further identify candidate mechanisms for neuronal activity patterns that could determine differences in circuit-specific dendritic development.

neuroscience↗