Biology subjects

Mai, L.

Publications and source records attributed to Mai, L..

6 recordsLinked to original sources

bioRxiv2026

An enzymatic metabolic sensing axis in taste cells detects glucose-yielding carbohydrates

Glucose is a potent reinforcer of intake, yet most foods contain complex saccharides that do not yield free glucose until after digestion. How the oral sensory system rapidly evaluates the potential metabolic value of food remains unclear. Here, we identify an oral enzymatic-metabolic sensing mechanism that enables detection of glucose-yielding carbohydrates independent of canonical sweet taste receptors. Using genetic, virogenetic, molecular, and behavioral approaches in mice, we show that glucokinase (GCK) in taste cells is necessary for the attraction to glucose-containing sugars. We further demonstrate that maltase glucoamylase (MGAM), a glycosidic enzyme expressed on and near taste cells, facilitates rapid oral sugar sensing. Disruption of either GCK or MGAM in the major taste fields selectively attenuates the attraction to maltose and a carbohydrate-rich mixed diet, establishing both as intermediaries in the initial transduction pathway for complex saccharides that ultimately give rise to nutrient reward. Molecular profiling of taste papillae further revealed that deficient sweet sensing was accompanied by a compensatory increase in lingual MGAM, highlighting an adaptive mechanism for maintaining oral carbohydrate sensitivity. Together, these findings reveal that the oral epithelium actively preprocesses and metabolically evaluates dietary carbohydrates, providing a mechanism for rapid estimation of energetic value prior to ingestion. Significance StatementCarbohydrates strongly motivate eating, yet most are consumed in complex forms that do not immediately release glucose. We show that the oral epithelium contains an adaptive enzymatic-metabolic sensing system that enables rapid evaluation of glucose-yielding carbohydrates before digestion. Two enzymes, maltase glucoamylase and glucokinase, act locally in taste fields to preprocess and metabolically assess complex sugars, biasing ingestive behavior toward energetically favorable foods. This mechanism operates independently of canonical sweet taste receptors and is dynamically regulated by dietary experience and receptor sensitivity. These findings reveal that the mouth actively estimates the energetic value of food prior to ingestion, reshaping our understanding of how nutrient sensing guides dietary choice.

neuroscience↗

bioRxiv2024

msCNVS: medium throughput single cell copy number variation sequencing with barcoded library construction free of preamplification toward clinical implementation

Single cell copy number variation sequencing (scCNV-seq) is valuable for genomic analysis of a variety of health and disease systems, yet the available methods either depend on either preamplification of the whole genome of each cell, special devices or untracable, which hinder scCNV-seq practice in clinics. Here we provide scalable multiplex scCNV-seq (msCNVS) that allows direct medium-throughput library construction for single cells, which are barcoded individually with Tn5 transposome in a microplate and immediately pooled for downstream processes, elevating the efficiency by orders of magnitude. An algorithm is developed on the distribution of segmented normalized read count density to identify the major peaks associating with integer copy numbers, further improving the accuracy for objective CNV calling. Here msCNVS faithfully distinguishes the unique CNV patterns of 5 cell lines. The individual msCNVS profiles of 70 individual K562 cells highly correlate with the profile of K562 bulk cells (R=0.90-0.98), and the triplicates of HeLa3 bulk cells correlated nearly perfect (R=0.99). The msCNVS CNV profiles of primary cell cultures of amniotic fluid are confirmed by G-banding karyotype analysis and chromosomal microarray analysis. Additionally, the coverage uniformity of msCNVS is superior to that of MDA and MALBAC and approaches what eMDA and DOP-PCR achieves. Furthermore, msCNVS detects CNV deletions in 2 stunted, abnormal blastocysts, one with CNV mosaicism, and uncovered variants of CNVs in circulated tumor cells, cancerous pleural effusion cells, and patient-derived xenograft nuclei. Thus, msCNVS promises a robust, reliable and highly efficient approach to genomic testing of precious and rare cells like those typically obtained in reproductive and cancer clinics. One-Sentence SummaryBy early pooling of multiple single cells individually barcoded with Tn5 transposome, msCNVS enables efficient CNV profiling of rare clinic samples

genomics↗

bioRxiv2023

The Identification of IL-4 as a Regulator of Chimeric Antigen Receptor T Cell Exhaustion

Durable response to chimeric antigen receptor T (CART) cell therapy remains limited in part due to CART cell exhaustion. We investigated the regulation of CART cell exhaustion with three independent approaches including: a genome-wide CRISPR knockout screen using a validated in vitro model for exhaustion, RNA and ATAC sequencing on baseline and chronically stimulated CART cells, and RNA and ATAC sequencing on pre-infusion CART cell products from responders and non-responders in the ZUMA-1 clinical trial. Each of these approaches identified IL-4 as a key regulator of CART cell dysfunction. Further, when CART cells were treated with IL-4, they developed signs of exhaustion, but when CART cells were treated with an IL-4 monoclonal antibody, they showed improved antitumor efficacy and reduced signs of exhaustion in preclinical models. Therefore, our study identified both a novel role for IL-4 on CART cells and the improvement of CART cell therapy through IL-4 neutralization. Statement of SignificanceIdentifying regulators of CART cell exhaustion will not only enhance the fields understanding of therapeutic failure, but it will also provide avenues to enhance CART cell efficacy. This study reveals both a novel role for IL-4 in exhaustion and a strategy to improve CART cell activity through IL-4 neutralization.

immunology↗

bioRxiv2023

Shortcut barcoding and early pooling for scalable multiplex single-cell reduced-representation CpG methylation sequencing at single nucleotide resolution

DNA methylation is essential for a wide variety of biological processes, yet the development of a highly efficient and robust technology remains a challenge for routine single-cell analysis. We developed a multiplex scalable single-cell reduced representation bisulfite sequencing (msRRBS) technology with off-the-shelf reagents and equipment. It allows cell-specific barcoded DNA fragments of individual cells to be pooled before bisulfite conversion, free of enzymatic modification or physical capture of the DNA ends, and achieves unparalleled read mapping rates of 62.51%, covering 59.95% of CpG islands and 71.62% of promoters in K562 cells on average. Its reproducibility is shown in duplicates of bulk cells with near perfect correlation (R=0.97-99). At a low 1 Mb of clean reads, msRRBS provides consistent coverage of CpG islands and promoters, outperforming the conventional methods with orders of magnitude reduction in cost. Here, we use this method to characterize the distinct methylation patterns and cellular heterogeneity of 6 cell lines, and leukemia and hepatocellular carcinoma models. Taking 4 hours of hands-on time, msRRBS offers a unique, highly efficient approach for dissecting methylation heterogeneity in a variety of multicellular systems.

genomics↗

bioRxiv2021

Ribosomal protein L23 drives the metastasis of hepatocellular carcinoma via upregulating MMP9

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths globally and tumor metastasis is one of the major causes of high mortality. To identify novel molecules contributing to HCC metastasis is critical to understanding the underlining mechanism of cancer metastasis. Here, combining the analyze based on published database and liver tissues from HCC patients, we identified that RNA binding protein L23 (RPL23) as a tumor metastasis driver in HCC. RPL23 was elevated in HCC and closely related to poor clinical outcomes. Furthermore, RPL23 depletion inhibited HCC cell proliferation, migration and invasion, while RPL23 overexpression promoted HCC cell metastasis. Mechanistically, RPL23 positively regulated MMP9 expression by stabilizing its mRNA. And increased MMP9 is involved in RPL23-mediated HCC metastasis. Importantly, RPL23 silencing reduced tumor growth and metastasis in vivo. In summary, we identified that RPL23 play an important role in HCC metastasis in an MMP9-dependent manner and may be a novel potential therapeutic target for HCC tumorigenesis and metastasis.

cancer biology↗

bioRxiv2019

Paternal aging affects the developmental patterns of ultrasonic vocalization induced by maternal separation in neonatal mice individually

Infant crying is an innate communicative behavior that is frequently impaired in certain neurodevelopmental disorders (NDDs). Since advanced paternal age is a reported risk factor for NDDs in offspring, we evaluated the impact of a fathers age on early vocal development in C57BL/6J mice. We recorded and applied a unique combination of computational analyses to ultrasonic vocalizations (USVs) emitted by mouse pups sired by young and aged fathers. Our data showed that advanced paternal age reduced the number and duration of USVs, and altered the syllable composition in pups. Moreover, pups born to young fathers showed convergent vocal characteristics with a rich repertoire during postnatal development, while those born to aged fathers exhibited more divergent vocal patterns with limited repertoire. Principal component analysis in conjunction with clustering analysis demonstrated that pups from aged fathers deviated from typical trajectories of vocal development, which were considered as atypical individuals. Thus, our study indicates that advanced paternal age has a significant effect on offsprings early vocal development. It is suggested that the trajectories of vocal development could be a useful marker of the NDD-like phenotype associated with the advanced paternal age. In addition, our comprehensive computational analysis described here is an effective approach to characterize the altered individual diversity relevant to neurodevelopmental disorders. One Sentence SummaryAdvanced paternal age affects vocal development in early postnatal mice, with more pups showing atypical developmental trajectories.

neuroscience↗