Zoological Research最新文献

Host-microbiota interactions represent a key axis in animal adaptation, especially in species displaying pronounced seasonal variation in behavior and physiology. In avian species, behavioral processes associated with reproduction may influence symbiotic microbial communities, yet the underlying mechanisms remain poorly resolved. The endangered crested ibis ( Nipponia nippon) exhibits a distinctive seasonal transition in plumage coloration, shifting from white in the non-breeding period to gray during breeding, a change linked to smearing behavior and deposition of black secretions from the neck region. In the present study, 16S rRNA sequencing across three body sites was performed to profile body surface microbiomes during breeding (gray-feather) and non-breeding (white-feather) stages. Breeding individuals exhibited lower microbial diversity, consistent with an influence of black neck secretions on microbiome structure. Microbial communities were differentiated more strongly by season than by body site, and microbial similarity among body sites increased during breeding, supporting redistribution of microbes through smearing behavior. Community assembly also showed clear season- and site-specific variation. Neck feathers exhibited a 36.5% better fit to the neutral model, indicating a stronger contribution of stochastic assembly, likely associated with microbial dispersal during smearing of black secretions. In contrast, neck skin showed a 36.3% lower neutrality and 11.87% more host-selected variants, indicating stronger deterministic selection associated with breeding-related secretions. These findings support a dual regulatory framework during breeding, in which behavioral smearing promotes microbial dispersal while physiological secretion strengthens host filtering. Such coordinated regulation likely drives seasonal microbiome variation and contributes to seasonal adaptation. Overall, this work provides novel insight into the integration of behavior and physiology in shaping host-microbiota interactions during critical life stages and establishes a microbiome-based perspective for crested ibis conservation.

Pain encompasses both sensory discrimination and affective evaluation, yet the precise behavioral and neurobiological mechanisms of this well-conserved phenomenon are still incompletely understood. Although the lateral hypothalamus area (LHA) has been implicated in nociceptive modulation, its underlying circuitry and causal mechanisms remain elusive. In this study, formalin-induced pain-like behaviors in mice were associated with attenuated activity in LHA ^GAD2-positive neurons, a pattern also observed during acute restraint stress in adult male transgenetic mice. Chemogenetic activation of LHA ^GAD2 neurons significantly alleviated formalin-evoked nociceptive responses and reduced aversive behavioral phenotypes. Additionally, functional analyses revealed a GABAergic projection from the LHA to the lateral habenula that selectively mitigated affective disturbances in a neuropathic pain model. In parallel, projections from LHA ^GAD2 neurons to specific neuronal subsets within the ventrolateral periaqueductal gray modulated nociceptive responses under neuropathic pain conditions. These findings delineate a dual-pathway mechanism by which LHA ^GAD2 neurons independently regulate sensory and affective dimensions of pain-like behavior, offering a basis for targeted pain relief. Collectively, the results reveal previously uncharacterized aspects of pain processing by discrete LHA GABAergic subpopulations and potentially inform the development of subregion- or cell type-specific therapies for pain management.

Low-salinity stress exerts strong constraints on ion homeostasis in crustaceans cultivated in coastal environments. Gills function as central osmoregulatory organs in crustaceans, coordinating transepithelial ion flux and acid-base balance; however, the cellular mechanisms governing gill adaptation to reduced salinity remain poorly understood. Here, integrated ultrastructural characterization and single-cell RNA sequencing (scRNA-seq) were applied to define cellular responses to low-salinity exposure in Exopalaemon carinicauda gills. Low salinity induced pronounced morphological remodeling in pillar cells. Single-cell transcriptomic profiling resolved 11 transcriptionally distinct populations, including two ionocyte lineages represented by pillar cells and septal cells. Comparative analyses demonstrated a marked expansion of pillar cell subcluster 3 under low-salinity stress, accompanied by enrichment of differentially expressed genes (DEGs) in ion transport pathways, notably hydrogen ion transport. Weighted gene co-expression network analysis identified coordinated up-regulation of hub genes associated with pH regulation within pillar cells. Pseudotime reconstruction further indicated that gill adaptation to low-salinity stress proceeds through a defined differentiation trajectory (cell fate 1) originating from pillar cells. Core stress-responsive genes in pillar cells, including V(H ⁺)-ATPases and cytoplasmic carbonic anhydrase, were predominantly associated with acid-base regulation. Collectively, these results delineate gill cellular heterogeneity and identify pillar cell-mediated regulatory mechanisms that underpin crustacean physiological adaptation to low-salinity environments.

Tetraploidy occurs infrequently in mammals but remains widespread in amphibians. Blastocyst complementation using xenogeneic transplantation of tetraploid embryonic stem cells (4 N-ESCs) represents a promising approach to mitigate organ shortages, yet robust generation of fully reconstituted organs in mammalian hosts remains elusive. In this study, CRISPR/Cas9, the Cre-LoxP system, and blastocyst complementation were combined to generate tetraploid mouse liver, heart, and pancreatic tissues. 4 N-ESCs (tdTomato-labeled) were established and shown to maintain stable pluripotency and tetraploidy, as confirmed by karyotyping and immunofluorescence analyses. Subsequently, these cells were microinjected into Hhex- and Pdx1-deficient blastocysts and Nkx2.5 lineage-ablated blastocysts, which were engineered to lack relevant organ-forming lineages. Tetraploid pups exhibited significantly reduced body mass and organ mass (liver and heart) relative to diploid controls ( P<0.05). Fluorescence-activated cell sorting demonstrated a significant 4 N-ESC (tdTomato-labeled) contribution within tetraploid organs (4N population) at E18.5, with tdTomato-positive fractions reaching 84.3% of hepatic cells, 67.8% of cardiac cells, and 73.4% of pancreatic cells. Single-cell transcriptome sequencing further revealed that tetraploidy markedly altered developmental trajectories and differentiation programs in liver and heart tissues, and 4 N-ESCs showed preferential integration into tetraploid liver and heart with a substantial contribution to pancreatic regeneration. Collectively, these findings support the feasibility of 4 N-ESC-based blastocyst complementation for human organ regeneration and establish a framework for developing strategies to alleviate organ shortages in clinical settings.

Although impaired nuclear translocation of glucocorticoid receptor (GR) contributes to hippocampal vulnerability in Alzheimer's disease (AD), its regulatory mechanisms remain poorly understood.Here, we identify Huntingtin-associated protein 1 (Hap1) as a critical regulator of GR nuclear translocation in the hippocampus. Specifically, Hap1 expression progressively declines in the APP/PS1 mouse hippocampus with aging and pathological progression. Hippocampal Hap1 knockdown induces cognitive deficits and synaptic loss, manifested as reduced dendritic complexity and spine density alongside impaired long-term potentiation (LTP), while exacerbating Aβ deposition in APP/PS1 mice. Crucially, Hap1 deficiency promotes GR ubiquitination and proteasomal degradation and, more critically, disrupts ligand-dependent GR nuclear translocation, thereby impairing GR-dependent BDNF transcription. Additionally, Hap1 knockdown elevates corticosterone levels and induces depressive-like behaviors, confirming hypothalamic-pituitary-adrenal (HPA) axis dysregulation. Our results establish disruption of Hap1-mediated GR nuclear translocation as a key pathomechanism linking intracellular transport defects to synaptic failure in AD, suggesting Hap1 modulation as a potential therapeutic avenue.

Aristolochic acid nephropathy (AAN) is a progressive form of kidney disease marked by acute tubular injury and interstitial fibrosis, ultimately leading to end-stage renal disease (ESRD). Despite regulatory restrictions, aristolochic acid (AA) remains a global health threat due to its presence in traditional herbal medicines. While mitochondria-mediated apoptosis is a hallmark of AA-induced tubular epithelial cell (TEC) injury, the upstream molecular mechanisms remain unclear. Here, we identify Z-DNA-binding protein 1 (ZBP1) as a key mediator of AA-induced kidney injury. Using Zbp1 knockout (Zbp1-/-) and Zα domain-mutant (ZαMut) mice, we show that loss of ZBP1 or its Z-form nucleic acid sensing capability protects against AA-induced renal dysfunction, apoptosis, and inflammation. Mechanistically, aristolochic acid I (AAI) induces mitochondrial oxidative stress and release of mitochondrial DNA (mtDNA), which adopts a Z-conformation and is recognized by ZBP1. The ZBP1 binding subsequently promotes RHIM-dependent interaction with RIPK1, culminating in caspase-8 activation and apoptotic cell death. Notably, ZBP1-mediated cell death was abolished by RIPK1 kinase inhibition or mutation, but unaffected by Ripk3 or Mlkl deletion, revealing a mechanism distinct from RIPK3/MLKL-dependent necroptosis. These findings uncover a previously unrecognized ZBP1-RIPK1-caspase-8 signaling axis driving non-canonical apoptosis in AAN and suggest that targeting this pathway may provide a novel therapeutic approach for nephrotoxin-induced kidney injury.

Tubulins undergo various posttranslational modifications (PTMs) that confer diverse functions to microtubules. Tubulin polyglutamylation is dynamically regulated by glutamylation and deglutamylation. AGBL5 is a deglutamylase that specifically removes glutamate at the branching point. Mutations in AGBL5 in humans are associated with retinitis pigmentosa, but the underlying mechanism remains undefined. Here, we generated an Agbl5 knockout mouse that showed tubulin hyperglutamylation in photoreceptors, resulting in progressive retinal degeneration. RNA-seq analysis revealed the altered ciliary function in the Agbl5 knockout. Transmission electron microscopy indicated an impaired inner scaffold in the connecting cilium (CC). Consequently, phototransduction proteins were mislocalized or downregulated in mutant rod and cone photoreceptors. Disk membranes in photoreceptor outer segments were disorganized. Immunofluorescence revealed that the recruitment of IFT88, kinesin-II, and dynein-2 to the CC was affected, implicating defective intraflagellar transport (IFT). Collectively, these findings demonstrate that tubulin glutamylation homeostasis regulated by AGBL5 is critical for photoreceptor survival by maintaining the structural integrity of the CC and normal protein trafficking through IFT.

CRISPR/dCas9-mediated epigenetic editing offers a versatile approach for transcriptional regulation without introducing DNA strand breaks. Although this strategy has been explored in a limited number of species, its application in aquatic vertebrates remains largely uncharacterized. In this study, ten-eleven translocation methylcytosine dioxygenase 1 ( tet1) was cloned and molecularly characterized in marine medaka ( Oryzias melastigma). Decitabine treatment identified fibroblast growth factor 2 ( fgf2) as a methylation-sensitive gene, with a regulatory CpG island located within its promoter region. Subsequently, a CRISPR/dCas9-Tet1CD activation system was constructed by fusing the catalytic domain of Tet1 (Tet1CD, Ala1352-Thr2034) to dCas9, enabling locus-specific DNA demethylation. Targeting fgf2, this CRISPR/dCas9-Tet1CD system induced efficient and selective demethylation of the CpG island, resulting in a maximal 2.41-fold increase in fgf2 transcript levels. Whole-genome bisulfite sequencing and transcriptomic analysis confirmed high on-target precision with minimal off-target effects. Epigenetic activation of fgf2 further modulated downstream gene networks associated with growth, promoting durable transcriptional enhancement and increased cellular proliferation. Collectively, these results establish a robust and highly specific epigenetic editing platform in marine medaka, providing a powerful tool for functional genomics studies and regulatory element analysis in aquatic models.