Biology subjects

Hsieh, M.-H.

Publications and source records attributed to Hsieh, M.-H..

7 recordsLinked to original sources

bioRxiv2025

Somatic TYK2 activating mutations in tumor-infiltrating T cells promote anti-cancer immunity

Cancer cells evolve to increase fitness and evade the immune system, but it is not clear if tumor infiltrating lymphocytes (TILs) undergo selection for somatic mutations that augment anti-cancer immunity. Using single molecule whole exome sequencing in TILs, we identified somatic mutations in Tyrosine-protein kinase 2 (TYK2), several of which increased TYK2 phosphorylation, JAK-STAT signaling, and interferon gamma signaling. Among these mutations, TYK2D810V was recurrently observed in patients with diverse cancer types. In vitro, TYK2D810V enhanced T cells effector functions and cytokine production. We generated mice with a germline Tyk2D807V mutation that recapitulated the human TYK2D810Vmutation. These mice were healthy and did not develop autoimmune disorders. However, they possessed enhanced anti-tumor effects in the context of syngeneic and autochthonous cancer models. Adoptive therapy with Tyk2D807V CD8 T cells also decreased cancer growth. Thus, naturally occurring mutations in non-malignant lymphocytes can antagonize cancer and inspire new immunotherapies strategies.

cancer biology↗

bioRxiv2025

Mechanistic basis for protection against fatty liver disease by CIDEB loss-of-function mutations

Background & AimsSomatic and germline CIDEB mutations are associated with protection from chronic liver diseases. The mechanistic basis and whether CIDEB suppression would be an effective therapy against fatty liver disease remain unclear. Methods21 CIDEB somatic mutations were introduced into cells to assess functionality. In vivo screening was used to trace Cideb mutant clones in mice fed normal chow, western (WD), and choline-deficient, L-amino acid-defined, high-fat (CDA-HFD) diets. Constitutive and conditional Cideb knockout mice were generated to study Cideb in liver disease. Isotope tracing was used to evaluate fatty acid oxidation and de novo lipogenesis. Transcriptomics, lipidomics, and metabolic analyses were utilized to explore molecular mechanisms. Double knockout models (Cideb/Atgl and Cideb/Ppara) tested mechanisms underlying Cideb loss. ResultsMost CIDEB mutations showed that they impair function, and lineage-tracing showed that loss-of-function clones were positively selected with some, but not all fatty liver inducing diets. Cideb KO mice were protected from WD, CDA-HFD, and alcohol diets, but had the greatest impact on CDA-HFD induced liver disease. Hepatocyte-specific Cideb deletion could ameliorate disease after MASLD establishment, modeling the impact of therapeutic siRNAs. Cideb loss protected livers via increased {beta}-oxidation, specifically through ATGL and PPARa activation. ConclusionsCideb deletion is more protective in some types of fatty liver disease. {beta}-oxidation is an important component of the Cideb protective mechanism. CIDEB inhibition represents a promising approach, and somatic mutations in CIDEB might predict the patient populations that might benefit the most.

physiology↗

bioRxiv2023

Positive selection of somatically mutated clones identifies adaptive pathways in metabolic liver disease

Somatic mutations in non-malignant tissues accumulate with age and insult, but whether these mutations are adaptive on the cellular or organismal levels is unclear. To interrogate mutations found in human metabolic disease, we performed lineage tracing in mice harboring somatic mosaicism subjected to non-alcoholic steatohepatitis (NASH). Proof-of-concept studies with mosaic loss of Mboat7, a membrane lipid acyltransferase, showed that increased steatosis accelerated clonal disappearance. Next, we induced pooled mosaicism in 63 known NASH genes, allowing us to trace mutant clones side-by-side. This in vivo tracing platform, which we coined MOSAICS, selected for mutations that ameliorate lipotoxicity, including mutant genes identified in human NASH. To prioritize new genes, additional screening of 472 candidates identified 23 somatic perturbations that promoted clonal expansion. In validation studies, liver-wide deletion of Bcl6, Tbx3, or Smyd2 resulted in protection against NASH. Selection for clonal fitness in mouse and human livers identifies pathways that regulate metabolic disease. HighlightsO_LIMosaic Mboat7 mutations that increase lipotoxicity lead to clonal disappearance in NASH. C_LIO_LIIn vivo screening can identify genes that alter hepatocyte fitness in NASH. C_LIO_LIMosaic Gpam mutations are positively selected due to reduced lipogenesis. C_LIO_LIIn vivo screening of transcription factors and epifactors identified new therapeutic targets in NASH. C_LI

cell biology↗

bioRxiv2023

Cancer mutations rewire the RNA methylation specificity of METTL3-METTL14

Chemical modification of RNAs is important for post-transcriptional gene regulation. The METTL3-METTL14 complex generates most N6-methyladenosine (m6A) modifications in mRNAs, and dysregulated methyltransferase expression has been linked to numerous cancers. Here we show that changes in m6A modification location can impact oncogenesis. A gain-of-function missense mutation found in cancer patients, METTL14R298P, promotes malignant cell growth in culture and in transgenic mice. The mutant methyltransferase preferentially modifies noncanonical sites containing a GGAU motif and transforms gene expression without increasing global m6A levels in mRNAs. The altered substrate specificity is intrinsic to METTL3-METTL14, helping us to propose a structural model for how the METTL3-METTL14 complex selects the cognate RNA sequences for modification. Together, our work highlights that sequence-specific m6A deposition is important for proper function of the modification and that noncanonical methylation events can impact aberrant gene expression and oncogenesis.

biochemistry↗

bioRxiv2022

IGFBP2 expressing midlobular hepatocytes preferentially contribute to liver homeostasis and regeneration

While midlobular hepatocytes in zone 2 are a recently identified cellular source for liver homeostasis and regeneration, these cells have not been exclusively fate mapped. We generated a Igfbp2-CreER knockin strain, which specifically labels midlobular hepatocytes. During homeostasis over 1 year, zone 2 hepatocytes increased in abundance from occupying 21% to 41% of the lobular area. After either pericentral injury with carbon tetrachloride or periportal injury with DDC, IGFBP2+ cells replenished lost hepatocytes in zones 3 and 1, respectively. IGFBP2+ cells also preferentially contributed to regeneration after 70% partial hepatectomy, as well as liver growth during pregnancy. Because IGFBP2 labeling increased substantially with fasting, we used single nuclear transcriptomics to explore zonation as a function of nutrition, revealing that the zonal division of labor shifts dramatically with fasting. These studies demonstrate the contribution of IGFBP2-labeled zone 2 hepatocytes to liver homeostasis and regeneration. HighlightsO_LILineage tracing showed that midlobular hepatocytes proliferate during homeostasis. C_LIO_LIZone 2 cells were protected from portal and centrilobular injuries and replaced lost hepatocytes. C_LIO_LIFasting induced significant changes in liver zonation. C_LI eTOC statementThe liver consists of different zones with spatial heterogeneity in their metabolic functions. Here, a new Igfbp2-CreER line enabled direct tracing of midlobular hepatocytes, which showed that IGFBP2+ cells serve as a source of new hepatocytes during normal homeostasis and regeneration.

developmental biology↗

bioRxiv2020

Human Surfactant Protein D Binds S1 and Receptor Binding Domain of Spike protein and acts as an entry inhibitor of SARS-CoV-2 Pseudotyped viral particles in vitro

Human SP-D is a potent innate immune molecule whose presence at pulmonary mucosal surfaces allows immune surveillance role against pulmonary pathogens. Higher levels of serum SP-D have been reported in patients with severe acute respiratory syndrome coronavirus-1 (SARS-CoV). Studies have suggested the ability of human SP-D to recognise spike glycoprotein of SARS-CoV; its interaction with HCoV-229E strain leads to viral inhibition in human bronchial epithelial (16HBE) cells. Previous studies have reported that a recombinant fragment of human SP-D (rfhSP-D) composed of 8 Gly-X-Y repeats, neck and CRD region, can act against a range of viral pathogens including influenza A Virus and Respiratory Syncytial Virus in vitro, in vivo and ex vivo models. In this context, this study was aimed at examining the likely protective role of rfhSP-D against SARS-CoV-2 infection. rfhSP-D showed a dose-responsive binding to S1 spike protein of SARS-CoV-2 and its receptor binding domain. Importantly, rfhSP-D inhibited interaction of S1 protein with the HEK293T cells overexpressing Angiotensin Converting Enzyme 2. The protective role of rfhSP-D against SARS-CoV-2 infection as an entry inhibitor was further validated by the use of pseudotyped lentiviral particles expressing SARS-CoV-2 S1 protein; ~0.5 RLU fold reduction in viral entry was seen following rfhSP-D treatment (10 g/ml). The results highlight the therapeutic potential of rfhSP-D in SARS-CoV-2 infection and merits pre-clinical studies in murine models.

microbiology↗

bioRxiv2018

The Synergistic Effect of Antioxidant Interaction between Luteolin and Chlorogenic Acid in Lonicera japonica

Lonicera japonica Thunb. is a flower that is used in traditional Chinese medicine to prevent the common cold. The two primary active compounds of the flower bud are luteolin, a flavonoid, and chlorogenic acid, a phenolic acid. Both active compounds have demonstrated antioxidant activity. The interactions between chemicals in a plant heavily influences its total antioxidant activity. We attempted to investigate the antioxidant interactions between the two chemicals in the plant. This study aims to investigate if the antioxidants luteolin and chlorogenic acid have a synergistic effect to inhibit free radicals when combined. A 2,2-diphenyl-1-picrylhydrazyl (DPPH*) assay was performed. The half maximal inhibitory concentration (IC50) of luteolin and chlorogenic acid were first determined and then combined at a 1:1 ratio. The combined inhibition capacity was then compared with the sum of the individual inhibition capacities. The IC50 of luteolin is 26.304 g{middle dot}ml-1 {+/-} 0.120 g{middle dot}ml-1 while the IC50 of chlorogenic acid is 85.529 g{middle dot}ml-1 {+/-} 4.482 g{middle dot}ml-1. The combined solution produced a free radical percentage inhibition of 77.617% {+/-} 5.470%, more than the percentage inhibition of the separate solutions. The experiment shows that luteolin and chlorogenic acid have a synergistic effect in inhibiting DPPH free radicals.

biochemistry↗