Biology subjects

Ha, Z.

Publications and source records attributed to Ha, Z..

3 recordsLinked to original sources

bioRxiv2025

Chronic alcohol exposure drives inflammaging and transposon derepression in hematopoietic stem and progenitor cells

Chronic alcohol use can cause pancytopenia and diminished immune responses against pathogens. However, its underlying molecular mechanisms remain unclear. Furthermore, whether chronic alcohol consumption directly induces inflammation in human hematopoietic stem progenitor cells (HSPCs) or whether it affects aging hematopoiesis differently is unknown. To examine how chronic alcohol use influences HSPCs, we performed single-cell RNA-seq in murine and human HSPCs and single-cell ATAC-seq in aged murine HSPCs following alcohol exposure. In the native murine bone marrow, chronic alcohol exposure primed HSPCs to differentiate into myeloid cells and to exhibit heightened inflammation, DNA damage, and epigenetic reactivation of transposable elements (TEs) in an age-dependent manner. Alcohol-exposed aged long-term hematopoietic stem cells (LT-HSCs) displayed increased chromatin accessibility at TE-containing loci correlated with aberrant TE transcription. This transposon derepression was associated with the accumulation of dsRNAs in aged bone marrow cells, and activation of innate immune pathways, perpetuating HSC inflammaging. Furthermore, we identified two epigenetically distinct LT-HSC clusters, LT-HSC1 and LT-HSC2, with the LT-HSC2 cluster expanding in response to chronic alcohol consumption, resembling activated HSCs. In xenotransplanted human HSPCs, chronic alcohol feeding resulted in a significant myeloid bias, heightened inflammation, upregulation of double-stranded RNA (dsRNA) sensors, activation of type I interferon responses, and increased expression of endogenous retroviruses. Despite these molecular alterations, we did not observe a decrease in long-term repopulation capacity in either human or murine HSCs. This suggests that HSC function may recover following alcohol cessation. However, previous chronic alcohol exposures imprint murine HSPCs to exhibit long-term myeloid bias and reduced cell cycle entry upon bacterial LPS challenge. Our data illuminate potential interactions between alcohol and aging that can reinforce inflammaging and epigenetic dysregulation in HSPCs. KeypointsO_LIAging perpetuates alcohol-induced myeloid bias, inflammation, DNA damage, and TE upregulation in murine HSPCs C_LIO_LIPrior chronic alcohol consumption does not affect long-term repopulation but causes persistent myeloid bias and inefficient stress responses after LPS challenge C_LIO_LIChronic alcohol consumption alters chromatin accessibility in TE-overlapping regions C_LIO_LIChronic alcohol consumption promotes myeloid bias, inflammation, and upregulation of endogenous retroviruses in xenotransplanted human HSPCs. C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/696246v2_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@e0357aorg.highwire.dtl.DTLVardef@1d702fdorg.highwire.dtl.DTLVardef@10553ddorg.highwire.dtl.DTLVardef@c4e62e_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2025

Development of a replication-defective MPXV platform for fundamental and therapeutic research

The recent global outbreaks of mpox highlight the urgent need for both fundamental research and antiviral development. However, studying monkeypox virus (MPXV), with its large and complex genome, remains challenging due to the requirement for high-containment facilities. Here, we describe a novel strategy for de novo assembly of MPXV clade IIb genomes in bacterial artificial chromosomes using transformation-associated recombination cloning. Leveraging CRISPR-Cas9 and Lambda Red recombination, we engineered replication-defective MPXV particles with dual deletions of OPG96 (M2R) and OPG158 (A32.5L)--genes essential for virion assembly, that are capable of recapitulating key stages of the viral life cycle. Our work demonstrates the utility of replication-defective MPXV particles as a reliable platform for high-throughput antiviral discovery, offering significant advantages for both fundamental virology studies and therapeutic development against orthopoxviruses.

microbiology↗

bioRxiv2019

RNA sequencing and lipidomic analysis of alveolar macrophages from normal and CD44 deficient mice

Alveolar macrophages (AMs) are CD44 expressing cells that reside in the alveolar space where they maintain lung homeostasis by serving critical roles in immunosurveillance and lipid surfactant catabolism. AMs lacking CD44 are unable to bind the glycosaminoglycan, hyaluronan, which compromises their survival and leads to reduced numbers of AMs in the lung. Using RNA sequencing, lipidomics and multiparameter flow cytometry, we demonstrate that CD44-/- mice have impaired AM lipid homeostasis and increased surfactant lipids in the lung. CD44-/- AMs had increased expression of CD36, a lipid scavenger receptor, as well as increased intracellular lipid droplets, giving them a foamy appearance. RNA sequencing revealed the differential expression of genes associated with lipid efflux and metabolism in CD44-/- AMs. Lipidomic analysis showed increased lipids in both the supernatant and cell pellet extracted from the bronchoalveolar lavage of CD44-/- mice. Phosphatidylcholine species, cholesterol, oxidized phospholipids and levels of reactive oxygen species (ROS) were increased in CD44-/- AMs. Oxidized phospholipids were more cytotoxic to CD44-/- AMs and induced greater lung inflammation in CD44-/- mice. Reconstitution of CD44+/+ mice with CD44-/- bone marrow as well as adoptive transfer of CD44-/- AMs into CD44+/+ mice showed that lipid accumulation in CD44-/- AMs occurred irrespective of the lung environment, suggesting a cell intrinsic defect. Administration of colony stimulating factor 2 (CSF-2), a critical factor in AM development and maintenance, increased AM numbers in CD44-/- mice and decreased phosphatidylcholine levels in the bronchoalveolar lavage, but was unable to decrease intracellular lipid accumulation in CD44-/- AMs. Peroxisome proliferator-activated receptor gamma (PPAR{gamma}), downstream of CSF-2 signaling and a regulator of lipid metabolism, was reduced in the nucleus of CD44-/- AMs, and PPAR{gamma} inhibition in normal AMs increased their lipid droplets. Thus, CD44 deficiency causes defects in AMs that lead to abnormal lipid accumulation and oxidation, which exacerbates oxidized lipid-induced lung inflammation. Collectively, these findings implicate CD44 as a regulator of lung homeostasis and inflammation.

immunology↗