Biology subjects

Loh, C.

Publications and source records attributed to Loh, C..

5 recordsLinked to original sources

bioRxiv2026

A 50-marker mass cytometry panel to expand analysis of the functional breadth of human immune cells

Human immune single-cell proteomic functional profiling has historically been performed with a limited number of inflammatory and/or cytotoxic readouts, capturing only a fraction of the complex orchestra of factors that comprise immune responses. Given the rising global crisis of chronic inflammation and the lack of clinically available treatment options, there is an urgent need to gain insight into the cell subsets that exhibit anti-inflammatory functional profiles and elucidate the mechanisms regulating these effector capacities. To address this, we developed a 50-marker CyTOF panel that enables unprecedented functional fingerprinting of human T cells, NK cells, monocytes, and B cells, detecting 24 intracellular targets. Healthy donor PBMCs were stimulated ex vivo and stained with this panel; from T cells, cytokines associated with the hallmark Type 1 (IFN-{gamma}, TNF-), Type 2 (IL-4, IL-5, and IL-13), and Type 17 (IL-17A, IL-17F) functional lineages were detected, as well as the chemokines MIP-1-, MIP1-{beta}, and IL-8 and the cell repair factor amphiregulin; from monocytes, IL-1{beta}, IL-35, and IL-8 were detected. To ascertain if some of the cytokines less commonly included in Intracellular Cytokine Staining (ICS) panels were produced in response to physiological TCR stimulation via viral peptides, we measured the T cell response to a CMV-EBV-Flu (CEF) pool; in addition to TNF-, IFN-{gamma}, and IL-2, we also found that individual T cells produced additional cytokines with IFN-{gamma} and TNF-, such as amphiregulin, MIP-1, IL-13, and IL-4. This mass cytometry panel provides an exceptionally broad and deeply resolved view of the functional diversity of human immune cells, surpassing, to our knowledge, the capabilities of previously reported approaches. Due to minimal signal overlap, CyTOF enables flexible panel customization, allowing markers and metal tags to be readily expanded or modified. Based on its resolution and adaptability, we anticipate that this panel and its derivatives will enable the discovery of novel immunomodulatory mechanisms for therapeutic intervention.

immunology↗

bioRxiv2025

Superior intracellular detection of cytokines, transcription factors, and phosphoproteins by CyTOF compared with fluorescent cytometry

Unraveling biological complexity, whether it be immune subset distribution in infectious disease(s), autoimmunity or tumor heterogeneity, requires technologies capable of single-cell proteomic analysis, such as flow cytometry. Surface immunophenotyping alone is often insufficient, as interrogating functional capacity is required to determine cellular mechanisms and effectively inform diagnostic biomarker discovery, therapeutics and vaccine development. However, large panels with intracellular markers are subject to numerous challenges, including spectral overlap and background cellular autofluorescence, reducing resolving power for rare subsets or populations defined by low-abundance expression. We posited that mass cytometry may overcome such limitations; to address this, three small (11-12-plex) clone-matched antibody panels were evaluated by spectral flow and mass cytometry. Panels were comprised of surface and intracellular targets (phospho-epitopes, transcription factors or cytokines) and designed to minimize fluorescence spectral overlap. CyTOF technology offered superior signal resolution across the range of intracellular targets. Improved signal-to-noise provided better resolution of phospho-events and transcription factor expression, in particular TOX and T-bet. Most strikingly, stimulation-specific IL-10+ and IL-13+ cells were only detected by CyTOF. Superior resolution of these cytokines enabled accurate population clustering, permitting more unique immune cell signatures to be found, including Tr1 and Tc2 populations, thus providing a more comprehensive picture of the immuno-diversity present. Our findings indicate that CyTOF technology could catalyze seminal discoveries in functional immune profiling, driving therapeutic design and diagnostics.

immunology↗

bioRxiv2023

Towards robust and generalizable representations of extracellular data using contrastive learning

Contrastive learning is quickly becoming an essential tool in neuroscience for extracting robust and meaningful representations of neural activity. Despite numerous applications to neuronal population data, there has been little exploration of how these methods can be adapted to key primary data analysis tasks such as spike sorting or cell-type classification. In this work, we propose a novel contrastive learning framework, CEED (Contrastive Embeddings for Extracellular Data), for high-density extracellular recordings. We demonstrate that through careful design of the network architecture and data augmentations, it is possible to generically extract representations that far outperform current specialized approaches. We validate our method across multiple high-density extracellular recordings. All code used to run CEED can be found at https://github.com/ankitvishnu23/CEED.

neuroscience↗

bioRxiv2023

Single-strand mismatch and damage patterns revealed by single-molecule DNA sequencing

Mutations accumulate in the genome of every cell of the body throughout life, causing cancer and other genetic diseases1-4. Almost all of these mosaic mutations begin as nucleotide mismatches or damage in only one of the two strands of the DNA prior to becoming double-strand mutations if unrepaired or misrepaired5. However, current DNA sequencing technologies cannot resolve these initial single-strand events. Here, we developed a single-molecule, long-read sequencing method that achieves single-molecule fidelity for single-base substitutions when present in either one or both strands of the DNA. It also detects single-strand cytosine deamination events, a common type of DNA damage. We profiled 110 samples from diverse tissues, including from individuals with cancer-predisposition syndromes, and define the first single-strand mismatch and damage signatures. We find correspondences between these single-strand signatures and known double-strand mutational signatures, which resolves the identity of the initiating lesions. Tumors deficient in both mismatch repair and replicative polymerase proofreading show distinct single-strand mismatch patterns compared to samples deficient in only polymerase proofreading. In the mitochondrial genome, our findings support a mutagenic mechanism occurring primarily during replication. Since the double-strand DNA mutations interrogated by prior studies are only the endpoint of the mutation process, our approach to detect the initiating single-strand events at single-molecule resolution will enable new studies of how mutations arise in a variety of contexts, especially in cancer and aging.

genomics↗

bioRxiv2022

Targeting Cblb-Notch1 axis as a novel immunotherapeutic strategy to boost CD8+ T-cells responses

A critical feature of cancer is the ability to induce immunosuppression and evade immune responses. Tumor-induced immunosuppression diminishes the efficacy of endogenous immune responses and decreases the efficacy of cancer immunotherapy. In this study, we describe a new immunosuppressive pathway in which adenosine promotes Cbl-b-mediated Notch1 degradation, causing suppression of CD8+ T-cells effector functions. Genetic KO and pharmacological inhibition of Cbl-b prevents Notch1 degradation in response to adenosine and reactivates its signaling. Reactivation of Notch1 results in enhanced CD8+ T-cell effector functions, anti-cancer response and resistance to immunosuppression. Our work demonstrates that targeting Cbl-b-Notch1 axis is a novel promising strategy for cancer immunotherapy.

cancer biology↗