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Tingting Liu

Publications and source records attributed to Tingting Liu.

3 recordsLinked to original sources
PubMed2026

ACE2 and Parkinsonism‑related bone metabolic alterations: signaling pathways and hub gene analysis.

Clinical co-occurrence of Parkinson's disease (PD) and age-related bone loss in elderly patients has garnered increasing attention, yet its molecular mechanisms remain incompletely elucidated. This study used an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model in Ace2-/y mice to investigate the regulatory mechanisms of bone-brain axis-related genes and signaling pathways. Behavioral tests assessed motor and non-motor symptoms. Immunohistochemistry, Western blot, and histopathological staining analyzed dopaminergic neuron activity, microglial activation, and bone metabolic abnormalities. GEO dataset transcriptomics and weighted gene co-expression network analysis (WGCNA) identified key hub genes, with receiver operating characteristic (ROC) curves evaluating their diagnostic value in public single-disease transcriptome data. MPTP significantly exacerbated motor dysfunction and depression-like behaviors; Ace2 deletion lowered total Wnt, β-catenin, BMP and IGF-1 protein abundance alongside reduced phosphorylation ratios of their downstream kinases in brain and bone, while upregulating RANKL/RANK/OPG-associated inflammatory mediators, accompanied by elevated total α-synuclein, Casp3 and Bax protein levels. The parallel reduction of these signaling proteins only suggests potential perturbation of related cascades; WGCNA identified 10 hub genes (e.g., DNM1, OCRL, OPA1), whose dysregulation was linked to synaptic dysfunction and inflammation. ROC analysis based on single-disease datasets showed high diagnostic accuracy for PD and `osteoporosis (OP) (AUC: 0.683-0.981), with core genes influencing synaptic, MAPK, Rap1, and Ras pathways. These preclinical findings indicate that Ace2 deficiency is associated with concurrent pathological abnormalities in the brain and transient bone metabolic disturbance under short-term MPTP treatment in growing young male mice; coordinated dysregulation of shared signaling pathways was observed in the two tissues, consistent with a potential bone-brain axis pathological phenotype, though causal bidirectional tissue cross-talk cannot be confirmed in the current experimental design, providing candidate targets that warrant further validation.

Animals↗
PubMed2026

cPRC1.2 and CTCF-mediated transition from poised to active chromatin loops at bivalent genes.

Polycomb Repressive Complex 1 (PRC1) and CCCTC-binding factor (CTCF) are critical regulators of 3D chromatin architecture that influence cellular transcriptional programs. Although the role of CTCF in chromatin organization is well-known, the involvement of PRC1 is less understood. In this study, we identify an unexpected role for the canonical Pcgf2-containing PRC1 complex (cPRC1.2) in activating bivalent genes. Hi-C revealed that cPRC1.2 forms chromatin loops at bivalent promoters, rendering them poised for activation. Pcgf2 deletion disrupts cPRC1.2 loops and impairs the transcriptional induction of crucial target genes necessary for neuronal differentiation. Furthermore, we identify CTCF enrichment at cPRC1.2 loop anchors and at Polycomb group (PcG) bodies, suggesting that PRC1 and CTCF cooperatively regulate chromatin loops. Through virtual 4C and other genomic analyses, we discover that establishing neuronal progenitor cell (NPC) identity involves a switch from cPRC1.2-mediated chromatin loops to CTCF-mediated active loops. Our results suggest a novel mechanism by which pre-formed PRC1 loops at lineage-specific genes maintain a poised state for subsequent CTCF-mediated active loops and gene activation in cell fate transitions.

CCCTC-Binding Factor↗
PubMed2024

PRC1 and CTCF-Mediated Transition from Poised to Active Chromatin Loops Drives Bivalent Gene Activation.

Polycomb Repressive Complex 1 (PRC1) and CCCTC-binding factor (CTCF) are critical regulators of 3D chromatin architecture that influence cellular transcriptional programs. Spatial chromatin structures comprise conserved compartments, topologically associating domains (TADs), and dynamic, cell-type-specific chromatin loops. Although the role of CTCF in chromatin organization is well-known, the involvement of PRC1 is less understood. In this study, we identified an unexpected, essential role for the canonical Pcgf2-containing PRC1 complex (cPRC1.2), a known transcriptional repressor, in activating bivalent genes during differentiation. Our Hi-C analysis revealed that cPRC1.2 forms chromatin loops at bivalent promoters, rendering them silent yet poised for activation. Using mouse embryonic stem cells (ESCs) with CRISPR/Cas9-mediated gene editing, we found that the loss of Pcgf2, though not affecting the global level of H2AK119ub1, disrupts these cPRC1.2 loops in ESCs and impairs the transcriptional induction of crucial target genes necessary for neuronal differentiation. Furthermore, we identified CTCF enrichment at cPRC1.2 loop anchors and at Polycomb group (PcG) bodies, nuclear foci with concentrated PRC1 and its tethered chromatin domains, suggesting that PRC1 and CTCF cooperatively shape chromatin loop structures. Through virtual 4C and other genomic analyses, we discovered that establishing neuronal progenitor cell (NPC) identity involves a switch from cPRC1.2-mediated chromatin loops to CTCF-mediated active loops, enabling the expression of critical lineage-specific factors. This study uncovers a novel mechanism by which pre-formed PRC1 and CTCF loops at lineage-specific genes maintain a poised state for subsequent gene activation, advancing our understanding of the role of chromatin architecture in controlling cell fate transitions.

Journal Article↗