Search bioRxiv⌕ Search

Biology subjects

Yang, Z.-H.

Publications and source records attributed to Yang, Z.-H..

12 recordsLinked to original sources

Understanding cephalopod regeneration: impact of sexual maturation, injury severity and general anesthesia on octopus arm restoration

Octopuses exhibit remarkable regenerative capacity, as shown by their ability to fully restore a whole arm. During this process, a complex appendage containing muscle, connective tissue, vasculature, suckers, sensory structures, peripheral nerves and the axial nerve cord (ANC) is regrown. Although the morphology of octopus regeneration is increasingly well described, the physiological variables that determine regenerative speed, including the potential contribution of ion-channel-dependent processes, remain poorly understood. In this work we examined the influence of reproductive state, injury severity, biological sex and magnesium chloride (MgCl2) anesthesia, on the rate of longitudinal arm regrowth. Reproductive stage was the strongest determinant of regenerative performance: pre-reproductive stage (pre-RS) animals showed robust regrowth, whereas reproductive stage (RS) animals regenerated significantly slower. In pre-RS animals, regeneration speed scaled strongly with injury severity, whereas this relationship was absent in RS animals. Biological sex did not independently predict regeneration speed, and MgCl2 exposure showed no long-term inhibitory effect on regeneration. Our final model explained 81.4% of variance in regeneration speed, with reproductive state and injury severity having major effects. These findings demonstrate that sexual maturation and optic-gland-mediated senescence act as an irreversible physiological block against somatic regeneration, and provide empirical support for mechanosensory and bioelectric-dependent scaling models of cephalopod limb restoration.

neuroscience↗

Z-RNA-ZBP1 axis drives Tau-mediated neurodegeneration

Although the causes of Tau aggregates vary, once Tau aggregates are formed, their neurotoxicity significantly contributes to neuronal death and cognitive decline in tauopathies, with Alzheimers disease (AD) being the most well-known example. Despite its central pathogenic role, however, effective therapeutic strategies targeting neurotoxicity of Tau remain poor. Here we demonstrate the pathogenic role of neuronal cell death in Tau-related neurodegeneration. Tau-expressing neurons undergo cell death through Z-DNA-binding protein 1 (ZBP1) activation triggered by endogenous Z-RNAs. These Z-RNAs are derived from reactivated transposable elements (TEs) that are typically silenced within heterochromatin. Tau aggregates show a strong affinity for H3K9me3-modified chromatin, effectively sequestering these epigenetic marks from Heterochromatin Protein 1 (HP1), thereby disrupting the condensation of constitutive heterochromatin. Clinically, an inverse correlation between ZBP1 expression levels in excitatory neurons and cognitive performance in AD patients was observed. Importantly, Zbp1 haploinsufficiency significantly ameliorated cognitive deficits in aged Tau-transgenic mice (24-month-old), highlighting the therapeutic potential of ZBP1 inhibition to strive against neurodegeneration in tauopathies.

neuroscience↗

Oxidation-Driven mtDNA B-Z Transition Activates ZBP1 to Mediate Acetaminophen Hepatotoxicity

Acetaminophen (APAP) overdose induces mitochondrial damage in hepatocytes, leading to secondary toxicity that resists to N-acetylcysteine (NAC) treatment and culminates in hepatocyte death and acute liver failure (ALF)1. The underlying mechanisms remain poorly understood, often necessitating liver transplantation2. Here, we identify oxidative modification-driven B-to-Z transitions in mtDNA as the central pathological driver of APAP-induced ALF. Upon APAP exposure, oxidized mtDNA fragments leak into the cytosol, activating ZBP1 signaling via its Z domain. Genetic inhibition of ZBP1 mitigates liver damage and improves survival. Using synthetic 12-bp dGdC duplexes, we demonstrate that 8-oxoG substitution, even under physiological salt concentrations, is sufficient to induce Z-DNA formation, enabling specific ZBP1 binding through its Z domain. The 8-oxoG repair enzyme OGG13, activated by TH107854, removes 8-oxoG modifications and reverses Z-DNA to B-DNA conformation. In mice with lethal APAP toxicity, delayed NAC treatment results in 50% mortality. In contrast, TH10785 monotherapy increases survival to 90%, while its combination with NAC achieves 100% survival. These results define the oxidized mt Z-DNA-ZBP1 axis as a critical driver of APAP hepatotoxicity, providing fundamental insights into DNA conformational dynamics and therapeutic opportunities in drug-induced liver failure.

cell biology↗

Immunoregulatory gene GIMAP6 suppresses lethal atherosclerotic vasculopathy and ischemic heart failure

Controlling hyperlipidemia has reduced but not eliminated atherosclerotic cardiovascular disease as a predominant cause of human mortality. Here, we report that loss of the immunoregulatory gene GTPase of immunity-associated protein 6 (GIMAP6), causes an inflammatory vasculopathy and accelerated atherosclerosis in the absence of hyperlipidemia. These pathologic changes in turn result in progressive cardiac ischemia, myocardial infarction, and heart failure, culminating in early death. In humans, rare deleterious GIMAP6 variants are associated with premature severe cardiovascular disease. These findings reveal GIMAP6 to play an important protective role against atherosclerotic cardiovascular disease whose identification offers opportunities for improved risk management and a target for new therapies.

immunology↗

ZBP1 Senses Splicing Aberration through Z-RNA to promote Cell Death

RNA splicing, a highly regulated process performed by the spliceosome, is crucial for eukaryotic gene expression and cellular function. Numerous cellular stresses including oncogenic insults dysregulate RNA splicing, often provoking inflammatory responses and cell death. However, the molecular signal produced by spliceosome aberration and how cell sensed and respond to it remain elusive. Here we show that spliceosome inhibition induces the widespread formation of unique, left-handed nucleic acids, Z-form nucleic acids (Z-NAs) from the nucleus. These Z-NAs were double-stranded RNA (dsRNA), rather than DNA-RNA hybrids, that were predominantly derived from transcripts of mis-spliced intronic RNA. Spliceosome inhibition induced the egress of these Z-RNA from the nucleus to the cytoplasm in an active manner. Sensing of the accumulation of Z-RNA in the cytosol by the host sensor ZBP1 triggered cell death, mainly for RIPK3-MLKL dependent necroptosis. Collectively, these findings delineate a previously uncharacterized mechanism in which Z-NA sensing by ZBP1 responds to global aberrations of RNA splicing to trigger inflammatory cell death.

cell biology↗

Apolipoprotein-L1 G1 variant contributes to hydrocephalus but not to atherosclerosis in apolipoprotein-E knock-out mice

IntroductionIn USA, six million individuals with Sub-Saharan ancestry carry two APOL1 high-risk variants, which increase the risk for kidney diseases. Whether APOL1 high-risk variants are independent risk factors for cardiovascular diseases is unclear and requires further investigation. MethodsWe characterized a mouse model to investigate the role of APOL1 in dyslipidemia and cardiovascular diseases. Transgenic mice carrying APOL1 (G0 and G1 variants) on bacterial artificial chromosomes (BAC/APOL1 mice) were crossed with the ApoE knock-out (ApoE-KO) atherosclerosis mouse model. The compound transgenic mice were evaluated for the impact of APOL1 on systemic phenotypes. ResultsApoE-KO mice carrying APOL1-G0 and APOL1-G1 did not show differences in the extent of atherosclerotic lesions or aortic calcification, as evaluated by Sudan IV staining and radiographic examination, respectively. However, [~]20% of ApoE-KO; BAC/APOL1-G1 mice developed hydrocephalus and required euthanasia. The hydrocephalus was communicating and likely was due to excess cerebrospinal fluid produced by the choroid plexus, where epithelial cells expressed APOL1. Single-nuclear RNA-seq of choroid plexus identified solute transporter upregulation and mTORC2 pathway activation in APOL1-G1-expressing epithelial cells. Further, in the All of Us cohort, we found higher hydrocephalus prevalence among individuals with the APOL1-G1 variant in both recessive and dominant models, supporting the mouse findings. ConclusionWhile APOL1-G1 expression in ApoE-KO mice did not worsen cardiovascular disease phenotypes, we uncovered hydrocephalus as a novel APOL1 risk allele-mediated phenotype. These findings extend the spectrum of APOL1-associated pathologies.

molecular biology↗

Pre-rRNA spatial distribution and functional organization of the nucleolus

The self-organized nucleolus is where the pre-ribosomal RNA (pre-rRNA) processing and pre-ribosomal ribonucleoprotein (RNP) assembly take place. Here we present the spatiotemporal distribution of pre-rRNA intermediates in the human nucleolus, revealing a segregated spatial distribution of small subunit (SSU) and large subunit (LSU) precursors. Notably, the 5 external transcribed spacer (5 ETS)-containing SSU pre-rRNAs are retained across FC-DFC-PDFC regions, while the internal transcribed spacer 2 (ITS2)-containing LSU pre-rRNAs move to PDFC-GC regions for processing. Inhibiting 5 ETS processing disrupts the SSU pre-rRNA distribution and the nested FC-DFC sub-nucleolar structure. Cells in amniotes possess a multi-layered nucleolus, whereas anamniotes have only a bipartite structure with a merged FC-DFC. Kinetic labeling of pre-rRNA outflow shows a 7-fold higher pace in tetrapartite nucleoli over that in bipartite nucleoli, indicating that the emergence of the nested FC-DFC may facilitate an efficient SSU pre-rRNA processing over the course of evolution. Collectively, depicting the spatiotemporal distribution of pre-rRNAs reveals a key role of processing steps in organizing the multi-layered nucleolus and suggests a possible evolutionary advantage of the multi-layered structure in amniotes.

molecular biology↗

A ZBP1 isoform blocks ZBP1-mediated cell death

ZBP1 is an interferon-induced nucleic acid (NA) sensor that senses unusual Z-form NA (Z-NA), a type of left-handed nucleic acid. More than that, the binding of ZBP1 with Z-NA promotes cell death and inflammation. However, the mechanisms that dampen ZBP1 activation to fine-tune inflammatory responses are unclear. Here we characterize a short isoform of ZBP1 (referred to as ZBP1-S) as an intrinsic suppresser of the inflammatory signaling mediated by full-length ZBP1. Compared with ZBP1, ZBP1-S protein has Z domains but no RHIM domains. Mechanistically, ZBP1-S depresses ZBP1-mediated cell death by competitive binding with Z-NA for Z domains of ZBP1. Cells from mice (Rip1D325A/D325A) with Cleavage-resistant RIP1-induced autoinflammatory (CRIA) syndrome are alive but sensitive to IFN-induced and ZBP1-depedent cell death. Intriguingly, Rip1D325A/D325A cells go death spontaneously when ZBP1-S was deleted, indicating the cell death driven by ZPB1 is under the check of ZBP1-S. Thus, our findings reveal that alternative splicing of Zbp1 represents an autogenic inhibition for regulating ZBP1 signaling and indicate that uncoupling of Z-NA with ZBP1 could be an effective strategy against auto-inflammations. HighlightO_LIZBP1-short isoform is expressed synchronously with ZBP1. C_LIO_LIZBP1-short isoform counteracts ZBP1 mediated cell death. C_LIO_LIZBP1-S suppresses ZBP1 signaling in an Z-domain dependent manner. C_LIO_LIZBP1-S prevents the autoactivation of ZBP1 in Rip1D325A/D325A cells. C_LI

immunology↗

Bypassing PELO-mediated ATPase activation of NLR is a common pathogenic cause of NLR-associated autoinflammatory diseases

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) constitute the largest family of pattern recognition receptors. These receptors are master regulators of innate immunity. Recently, PELO-driven ATPase activation of NLRs was demonstrated as a critical step in NLR activation. Linkage studies in human with various inherited autoinflammatory conditions have revealed an extensive array of mutations and polymorphisms within NLRs. However, the precise mechanisms by which genetic variations in NLR genes contribute to disease onset remain largely elusive. Here we comprehensively analyze dozens of naturally occurring mutations across multiple human NLRs, and demonstrate that NLRs harboring pathogenic mutations in their NACHT domain--not those with non-pathogenic variants--exhibit spontaneous PELO-independent ATPase activation. This aberrant activation triggers corresponding NLR to mediate inflammatory responses. Thus, bypassing the PELO-checkpoint for ATPase activation is a major disease-causing mechanism underlying NLR mutations. Furthermore, quantifying this aberrant ATPase activation could serve as an assessment tool for classifying the pathogenesis of NLR-associated diseases.

immunology↗

Artificial intelligence redefines RNA virus discovery

Current metagenomic tools can fail to identify highly divergent RNA viruses. We developed a deep learning algorithm, termed LucaProt, to discover highly divergent RNA-dependent RNA polymerase (RdRP) sequences in 10,487 metatranscriptomes generated from diverse global ecosystems. LucaProt integrates both sequence and predicted structural information, enabling the accurate detection of RdRP sequences. Using this approach we identified 161,979 potential RNA virus species and 180 RNA virus supergroups, including many previously poorly studied groups, as well as RNA virus genomes of exceptional length (up to 47,250 nucleotides) and genomic complexity. A subset of these novel RNA viruses were confirmed by RT-PCR and RNA/DNA sequencing. Newly discovered RNA viruses were present in diverse environments, including air, hot springs and hydrothermal vents, and both virus diversity and abundance varied substantially among ecosystems. This study advances virus discovery, highlights the scale of the virosphere, and provides computational tools to better document the global RNA virome. In briefA deep learning algorithm (LucaProt) that integrates both sequence and predicted structural information was employed to identify highly divergent RNA viral "dark matter" in 10,487 metatranscriptomes from diverse global ecosystems. A total of 161,979 potential RNA virus species and 180 RNA virus supergroups was unveiled using this AI approach, including many understudied groups.

microbiology↗

Ribosome-rescuer PELO catalyzes the oligomeric assembly of NLR family proteins via activating their ATPase

NOD-like receptors (NLRs) are pattern recognition receptors for diverse innate immune responses. Self-oligomerization after engagement with a ligand was a generally accepted model for the activation of each NLR. We report here that a catalyzer is required for the self-oligomerization. Protein pelota homolog (PELO, Dom34 in yeast), a well-known surveillance factor in translational quality control/ribosome rescue, interacts with all cytosolic NLRs and activates their ATPase. In the case of flagellin-initiated NLRC4 inflammasome activation, flagellin-bound NAIP5 recruits the first NLRC4 and then PELO is required for correctly assembling the rest of NLRC4s into the NLRC4 complex one by one by activating the NLRC4 ATPase. Stoichiometric and functional data revealed that PELO cannot be a structural constituent of NLRC4 inflammasome but a powerful catalyzer for its assembly. The catalytic role of PELO in the activation of cytosolic NLRs is unexpected and may break new ground for future studies of NLR family members.

immunology↗

Alterations in bile acid metabolizing gut microbiota and specific bile acid genes as a precision medicine to subclassify NAFLD

Background & AimsMultiple mechanisms for the gut microbiome contributing to the pathogenesis of non-alcoholic fatty liver disease (NAFLD) have been implicated. Here, we aim to investigate the contribution and potential application for altered bile acid (BA) metabolizing microbe in NAFLD using whole metagenome sequencing (WMS) data. Methods86 well-characterized biopsy-proven NAFLD patients and 38 healthy controls were included in the discovery cohort. Assembly-based analysis was performed to identify BA-metabolizing microbes. Statistical tests, feature selection and microbial interaction analysis were integrated to identify microbial alterations and markers in NAFLD. An independent validation cohort was subjected to similar analyses. ResultsNAFLD microbiota exhibited decreased diversity and microbial interactions. We established a classifier model with 53 differential species exhibiting a robust diagnostic accuracy (AUC=0.97) for dectecting NAFLD. Next, 8 important differential pathway markers including secondary BA biosynthesis were identified. Specifically, increased abundance of 7-HSDH, baiA and baiB were detected in NAFLD. Further, 10 of 50 BA-metabolizing metagenome-assembled genomes (MAG)s, from Bacteroides ovatus and Eubacterium biforme, were dominant in NAFLD and interplayed as a synergetic ecological guild. Importantly, two subtypes of NAFLD patients were observed according to secondary BA metabolism potentials. Elevated capability for secondary BA biosynthesis was also observed in the validation cohort. ConclusionsWe identified novel bacterial BA-metabolizing genes and microbes that may contribute to NAFLD pathogenesis and serve as disease markers. Microbial differences in BA-metabolism and strain-specific differences among patients highlight the potential for precision medicine in NAFLD treatment.

pathology↗