Biology subjects

Chew, S.

Publications and source records attributed to Chew, S..

7 recordsLinked to original sources

bioRxiv2026

Inter-organ communication shapes human metabolic tissue states and resolves anti-diabetic drug response modes in a six-tissue microphysiological system

Systemic glucose regulation depends on coordinated signaling among metabolically specialized tissues, yet most human in vitro models capture only limited portions of this network. Here, we developed and benchmarked a perfused human six-tissue MPS by combining AnthroHive, a recirculating perfusion platform, with MOTIVE-6, a six-compartment Multiorgan Tissue Interaction Vessel, to culture human gut epithelium, pancreatic islets, liver organoids, adipocytes, skeletal muscle, and midbrain-patterned brain organoids in a microphysiological system. Shared perfusion redirected engineered tissue states toward tissue-aligned metabolic, endocrine, absorptive, contractile, and neural-associated programs while reducing selected isolation-associated stress and remodeling signatures. Under High nutrient conditions, however, multi-tissue interaction shifted liver and islet responses toward inflammatory and nutrient-stress-associated gene expression, indicating context-dependent effects of cross-compartment signaling. Graded nutrient exposure resolved a staged circuit trajectory: Low nutrient conditions supported maintenance-associated programs, Mid nutrient exposure induced compensatory endocrine and anabolic remodeling with declining net glucose depletion, and High nutrient exposure shifted the system toward stress-associated metabolic dysfunction. Under High conditions, metformin and semaglutide produced distinct response modes. Metformin preserved circuit-level glucose handling without increasing insulin or C-peptide accumulation, while semaglutide remodeled gut, brain organoid, islet, and liver organoid transcriptional programs linked to nutrient sensing, epithelial maintenance, endocrine signaling, and neurometabolic state. Together, this study establishes a benchmarked human six-tissue MPS resource, paired with tissue-resolved transcriptomic, shared-media metabolomic, functional, endocrine, and inflammatory datasets, for investigating how tissue interaction, nutrient availability, and metabolic therapies reshape glucose-regulatory networks. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/726943v1_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@181cdfforg.highwire.dtl.DTLVardef@fb211eorg.highwire.dtl.DTLVardef@13b7284org.highwire.dtl.DTLVardef@1db7543_HPS_FORMAT_FIGEXP M_FIG C_FIG Created in BioRender. Trapecar, M. (2026) https://BioRender.com/a4tl7nv

bioengineering↗

bioRxiv2022

Timed Notch Inhibition drives Photoreceptor fate specification in Human Retinal Organoids

PurposeTransplanting photoreceptors from human pluripotent stem cell derived retinal organoids have the potential to reverse vision loss in affected individuals. However, transplantable photoreceptors are only a subset of all cells in the organoids. Hence the goal of our current study was to accelerate and synchronize photoreceptor differentiation in retinal organoids by inhibiting the Notch signaling pathway at different developmental time-points using a small molecule, PF-03084014 (PF). MethodsHuman induced pluripotent stem cell (hiPSC)- and embryonic stem cells (hESC)-derived retinal organoids were treated with 10M PF for three days at day 45 (D45), D60, D90 and D120 of differentiation. Organoids collected at 14-, 28-, and 42-days post-PF treatment were analyzed for progenitor and photoreceptor markers and Notch pathway inhibition by immunohistochemistry (IHC), quantitative PCR (qPCR) and bulk RNA-seq (n=3-5 organoids from 3 independent experiments). ResultsRetinal organoids collected at 14-days post-PF treatment showed a decrease in progenitor markers (KI67, VSX2, PAX6, and LHX2) and an increase in differentiated pan-photoreceptor markers (OTX2, CRX, and RCVRN) at all organoid stages except D120. PF-treated organoids at D45 and D60 exhibited an increase in cone photoreceptor markers (RXRG and ARR3). PF-treatment at D90 revealed an increase in cone and rod photoreceptors markers (ARR3, NRL, and NR2E3). Bulk RNA-seq analysis mirrored the IHC data and qPCR confirmed Notch effector inhibition. ConclusionsTiming the Notch pathway inhibition in human retinal organoids to align with progenitor competency stages can yield an enriched population of early cone or rod photoreceptors.

developmental biology↗

bioRxiv2021

Alzheimer's disease alters astrocytic functions related to neuronal support andtranscellular internalization of mitochondria

Under physiological conditions in vivo astrocytes internalize and degrade neuronal mitochondria in a process called transmitophagy. Mitophagy is widely reported to be impaired in neurodegeneration but it is unknown whether and how transmitophagy is altered in Alzheimers disease (AD). Here we report that the internalization and degradation of neuronal mitochondria are significantly increased in astrocytes isolated from aged AD mouse brains. We also demonstrate for the first time a similar phenomenon between human neurons and AD astrocytes, and in murine hippocampi in vivo. The results suggest the involvement of S100a4 in impaired mitochondrial transfer between neurons and aged AD astrocytes. Significant increases in the mitophagy regulator Ambra1 were observed in the aged AD astrocytes. These findings demonstrate altered neuron-supporting functions of aged AD astrocytes and provide a starting point for studying the molecular mechanisms of transmitophagy in AD.

neuroscience↗

bioRxiv2021

Subacute Inhalation of Ultrafine Particulate Matter Triggers Inflammation Without Altering Amyloid Beta Load in 5xFAD mice.

Epidemiological studies reveal that air pollution exposure may exacerbate neurodegeneration. Ultrafine particles (UFPs) are pollutants that remain unregulated in ambient air by environmental agencies. Due to their small size (<100nm), UFPs have the most potential to cross the bodily barriers and thus impact the brain. However, little information exists about how UFPs affect brain function. Alzheimers disease (AD) is the most common form of dementia, which has been linked to air pollutant exposure, yet limited information is available on the mechanistic connection between them. This study aims to decipher the effects of UFPs in the brain and periphery using the 5xFAD mouse model of AD. In our study design, AD mice and their wildtype littermates were subjected to 2-weeks inhalation exposure of UFPs in a whole-body chamber. That subacute exposure did not affect the blood-brain barrier integrity or amyloid-beta accumulation. However, when multiple cytokines were analyzed, we found increased levels of proinflammatory cytokines in the brain and periphery, with a predominant alteration of interferon-gamma in response to UFP exposure in both genotypes. Following exposure, mitochondrial superoxide dismutase was significantly upregulated only in the 5xFAD hippocampi, depicting oxidative stress induction in the exposed AD mouse group. These data demonstrate that short-term exposure to inhaled UFPs induces inflammation without affecting amyloid-beta load. This study provides a better understanding of adverse effects caused by short-term UFP exposure in the brain and periphery, also in the context of AD. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/459017v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@479511org.highwire.dtl.DTLVardef@18bc59aorg.highwire.dtl.DTLVardef@15a0240org.highwire.dtl.DTLVardef@49f911_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2020

Disease specific alterations in the olfactory mucosa of patients with Alzheimer's disease

Olfactory dysfunction manifests early in several neurodegenerative disorders. Olfaction is orchestrated by olfactory mucosal cells located in the upper nasal cavity. However, it is unclear how this tissue reflects key neurodegenerative features in Alzheimers disease. Here we report that Alzheimers disease olfactory mucosal cells obtained from live individuals secrete toxic amyloid-beta. We detail cell-type-specific gene expression patterns, unveiling 147 differentially expressed disease-associated genes compared to the cognitively healthy controls, and 5 distinct populations in globose basal cell -, myofibroblast-, and fibroblast/ stromal - like cells in vitro. Overall, coordinated alteration of RNA and protein metabolism, inflammatory processes and signal transduction were observed in multiple cell populations, suggesting a key role in pathophysiology. Our results demonstrate the potential of olfactory cell cultures in modelling Alzheimers disease advocate their use for diagnostic purposes. Moreover, for the first time we provide single cell data on olfactory mucosa in Alzheimers disease for investigating molecular and cellular mechanisms associated with the disease.

neuroscience↗

bioRxiv2020

Bifidobacteria-mediated immune system imprinting early in life

Immune-microbe interactions early in life influence an individuals risk of developing allergies, asthma and some autoimmune disorders. Breastfeeding helps guide the development of healthy immune-microbe relationships, in part by providing nutrients to specialized microbes that in turn benefit the host and its developing immune system. Such bacteria having co-evolved with humans are associated with reduced risks of immune mediated diseases but are increasingly rare in modern societies. Here we map an immunological sequence of events, triggered by microbial colonization that distinguish children with different gut bacterial composition. Lack of bifidobacterial species is associated with elevated markers of intestinal inflammation and immune dysregulation and in a randomized trial of breastfed infants, the infant-adapted Bifidobacterium infantis EVC001 silenced intestinal Th2 and Th17 immune responses, while inducing IFN{beta}, and its metabolites skew T-cell polarization in vitro, from Th2 towards Th1, suggesting a healthier immune imprinting during the first critical months of life. HIGHLIGHTSAn ordered sequence of immune changes after birth, driven by microbial interactions Low gut Bifidobacterium abundance is associated with markers of intestinal inflammation Feeding B. infantis EVC001 silenced intestinal Th2 and Th17 but upregulates IFN{beta} B. infantis EVC001 metabolites and/or enteric cytokines skew naive T-cell polarization towards Th1 and away from Th2

immunology↗

bioRxiv2019

TGFβ drives mitochondrial dysfunction in peripheral blood NK cells during metastatic breast cancer

Natural Killer (NK) cells provide important protection from cancer and are a key requirement for particular immunotherapies. In activated NK cells, a metabolic response towards increased glycolysis and oxidative phosphorylation is crucial for NK cell effector functions. However, there is accumulating evidence that NK cells become dysfunctional during chronic inflammatory diseases, such as human breast cancer. This dysfunction is apparent in peripheral blood NK cells and can impact on normal NK cell immune responses and their effective targeting during immunotherapy. Herein, we demonstrate that prolonged cytokine stimulation combined with metabolic restriction, through inhibition of mTORC1, is sufficient to induce persistent dysfunction in human NK cells. TGF{beta}, also restricted NK cell metabolism and promoted persistent NK cell dysfunction. NK cells from patients with metastatic breast cancer had profound metabolic defects in glycolysis and mitochondrial function, and clear structural differences in NK cell mitochondrial morphology. Importantly, blocking elevated TGF{beta} improved readouts of metabolism and restored IFN{gamma} production in patient NK cells.

immunology↗