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Biomedical subjects

Hong Zhou

Publications and source records attributed to Hong Zhou.

5 recordsLinked to original sources

Skin-innervating glutamatergic neurons modulate aging.

Peripheral nerves regulate skin homeostasis by secreting neurotransmitters, but their role during skin aging remains incompletely understood. Here, we report that cutaneous denervation accelerates skin aging, as evidenced by collagen reduction. Neurofilament heavy chain (Nefh) is decreased in aged skin and is predominantly expressed in vesicular glutamate transporter 2-positive (Vglut2+) skin-innervating glutamatergic neurons. Notably, dermal fibroblasts, the primary producers of collagen, frequently contact Nefh+ nerve fibers. Moreover, Nefh deletion in Vglut2+ glutamatergic neurons drives skin fibroblast senescence and collagen loss, whereas additional glutamate improves skin aging phenotypes. Mechanistically, cyclin-dependent kinase 5 (Cdk5) interacts with both Nefh and Vglut2 and maintains glutamate release and collagen homeostasis. Additionally, in skin fibroblasts, solute carrier family 1 member 3 (Slc1a3) governs the collagen-promoting and anti-senescence functions of glutamate. Together, these findings reveal Nefh-mediated glutamatergic neuromodulation of skin aging and provide therapeutic targets for aging-related skin disorders.

Animals

Genomic and evolutionary basis of parthenogenesis in a disease-vector tick species.

Haemaphysalis longicornis is an important tick species and pathogen vector characterized by the co-circulation of triploid parthenogenetic and diploid bisexual strains. However, the evolutionary basis of parthenogenesis in this species is unclear. Here we report reference-quality, haplotype-resolved genome assemblies of the parthenogenetic strain and two reference-quality genomes of the bisexual strains. Comparative genomic analysis revealed high collinearity between the parthenogenetic and bisexual genomes, with a stable chromosomal architecture maintained among the three haplotypes of the parthenogenetic strain. The parthenogenetic H. longicornis genome exhibited a major expansion in cell cycle-related gene families, including the inhibitor of apoptosis protein (IAP) family, but was characterized by a contraction in other gene families. Population resequencing of 179 individuals revealed two distinct subpopulations, with chromosome 7 harbouring high genetic differentiation and several candidate genes probably associated with parthenogenesis. Functional experiments showed that knockdown of the BIRC5 gene, a member of the IAP family, suppressed oviposition in both strains, with the parthenogenetic strain exhibiting milder adverse effects probably due to a stronger transcriptional response. Overall, our results reveal the genomic and evolutionary features associated with polyploid parthenogenesis in H. longicornis.

Animals

ATF4-histone 2-hydroxyisobutyrylation feedback loop drives sepsis-induced inflammation.

BACKGROUND AND PURPOSE: The role and mechanisms of lysine 2-hydroxyisobutyrylation (Khib) in the acute inflammatory phase of sepsis remain unclear. We investigated the function and underlying mechanisms of histone H4 lysine 5 2-hydroxyisobutyrylation (H4K5-hib) in sepsis-induced inflammation in vivo and in vitro. EXPERIMENTAL APPROACH: Acute sepsis was induced by caecal ligation and puncture (CLP) in mice, and inflammatory responses were modelled in lipopolysaccharide (LPS)-stimulated macrophages. CUT&Tag-seq was used to identify genomic targets associated with H4K5-hib and activating transcription factor 4 (ATF4). Immunofluorescence, Western blotting, qPCR, dual-luciferase assays, and ELISA were performed to investigate the underlying mechanisms. KEY RESULTS: H4K5-hib levels were increased in macrophages during the acute inflammatory phase of sepsis. LPS stimulation enhanced H4K5-hib enrichment at the ATF4 promoter, thereby promoting ATF4 transcription. Inhibition of EP300-mediated 2-hydroxyisobutyrylation or mutation of H4K5 abolished ATF4 activation. Increased H4K5-hib activated the ATF4/NLRP3 signalling axis, promoting inflammasome assembly and amplifying inflammatory responses. ATF4 directly bound to the EP300 promoter and enhanced its transcription, forming a positive feedback loop that further increased H4K5-hib levels. In CLP-induced sepsis, pharmacological inhibition of EP300 or ATF4 reduced H4K5-hib levels and suppressed NLRP3 inflammasome activation. CONCLUSION AND IMPLICATIONS: These findings reveal a previously unrecognized epigenetic mechanism underlying sepsis-induced inflammation and identify the EP300/ATF4/H4K5-hib positive feedback loop as a potential therapeutic target for sepsis.

Animals

TRIM49 Deficiency Stabilizes a Galectin-3/EGR1 Transcriptional Complex That Drives Invasiveness of Gastric Adenocarcinoma.

UNLABELLED: Tissue invasion is an initiating step of the cancer metastatic cascade. Unraveling the mechanisms underlying intracellular signaling pathway rewiring that activates downstream transcriptional machinery to drive invasiveness could help identify improved strategies to prevent and treat metastasis. Through an unbiased genome-wide CRISPR screen in a mouse model of gastric adenocarcinoma (GAC), an E3 ubiquitin ligase, tripartite motif-containing protein 49 (TRIM49), was identified as a potent suppressor of cancer invasiveness. In two thirds of GAC, TRIM49 expression was downregulated in invading cancer cells, in which TRIM49 deficiency correlated with deeper tumor infiltration and lymph node metastasis and was indicative of shorter overall patient survival. In multiple orthotopic GAC mouse models, TRIM49-deficient cancer cells were highly infiltrative, leading to multiorgan metastasis. Mechanistically, galectin-3, a putative regulator of cancer invasion, was stabilized in TRIM49-deficient cancer, largely because of the failure to undergo TRIM49-mediated polyubiquitination and proteasomal degradation. Consequently, galectin-3 assembled a complex with EGR1, thereby regulating transcriptional activities of a proinvasive gene module. As the galectin-3/EGR1 complex acted as a key node relaying proinvasive signaling, its disruption using GB1107, an oral galectin-3 inhibitor, suppressed tissue infiltration and metastasis of patient-derived xenografts. Taken together, a proinvasive galectin-3/EGR1 transcriptional complex was exploited by TRIM49-deficient GAC to fuel tissue invasion, representing an Achilles' heel that is potentially targetable to prevent metastasis. SIGNIFICANCE: A proinvasion galectin-3/EGR1 transcriptional complex is a therapeutic vulnerability in the highly invasive TRIM49-deficient gastric adenocarcinoma, which can be disrupted by the oral galectin-3 inhibitor GB1107 to prevent cancer spreading.

Stomach Neoplasms

Shared genetic architecture between DTI-ALPS traits and neurodegenerative diseases.

INTRODUCTION: Diffusion tensor image analysis along the perivascular space (DTI-ALPS) index is associated with neurodegenerative diseases (NDDs), but its shared genetic basis with NDDs remains unclear. METHODS: By integrating genome-wide association datasets for three DTI-ALPS traits and seven NDDs, we quantified polygenic overlap using MiXeR, identified shared loci using conditional and conjunctional false discovery rate analyses, and performed gene mapping, enrichment, temporal expression, and transcriptome-wide association analyses. RESULTS: DTI-ALPS traits showed widespread but heterogeneous polygenic overlap with NDDs. We identified 22 shared loci, including novel associations implicating GAK and SIAH3, with the strongest convergence at 17q21.31. Shared loci mapped to 183 protein-coding genes enriched in the endolysosomal system and microtubule cytoskeleton. These genes showed similar temporal expression patterns, and 45 were associated with both DTI-ALPS traits and NDDs. DISCUSSION: These findings reveal a shared genetic architecture between DTI-ALPS traits and NDDs, highlighting mechanisms that may contribute to their overlap.

Neurodegenerative Diseases