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Zhou, Z.

Publications and source records attributed to Zhou, Z..

At least 235 records · Page 13Linked to original sources

ProAffinity-GNN: A Novel Approach to Structure-based Protein-Protein Binding Affinity Prediction via a Curated Dataset and Graph Neural Networks

Protein-protein interactions (PPIs) are crucial for understanding biological processes and disease mechanisms, contributing significantly to advances in protein engineering and drug discovery. The accurate determination of binding affinities, essential for decoding PPIs, faces challenges due to the substantial time and financial costs involved in experimental and theoretical methods. This situation underscores the urgent need for more effective and precise methodologies for predicting binding affinity. Despite the abundance of research on PPI modeling, the field of quantitative binding affinity prediction remains underexplored, mainly due to a lack of comprehensive data. This study seeks to address these needs by manually curating pairwise interaction labels on all available 3D structures of proteins complexes, with experimentally determined binding affinities, creating the largest dataset for structure-based pairwise protein interaction with binding affinity to date. Subsequently, we introduce "ProAffinity-GNN", a novel deep learning framework using protein language model and graph neural network (GNN) to improve the accuracy of prediction of structure-based protein-protein binding affinities. The evaluation results across several benchmark test sets demonstrate that ProAffinity-GNN not only outperforms existing models in terms of accuracy but also shows strong generalization capabilities.

bioinformatics↗

PFKP regulates AXL-MET oncogenic and metabolic pathways in lung cancer

ObjectivePFKP (Phosphofructokinase, Platelet Type isoform), as an essential metabolic enzyme, contributes to the high glycolysis rates seen in cancers, while its role in oncogenic pathways, especially from a non-metabolic aspect, is not fully understood. MethodsHere we performed a comprehensive analysis of published RNA-seq, microarray data, and immunohistochemistry of tissue microarray to evaluate the significance of PFKP expression in non-small cell lung cancer (NSCLC). Functionally, we tested the cell proliferation, colony formation, invasion, and migration upon PFKP knockdown in lung cancer cells. Mechanistically, we performed RNA-seq, DIA-mass spectrum, western blot, and qPCR to probe the change of cell signaling pathways upon PFKP silencing. Co-immunoprecipitation and mass spectrum were used to uncover potential PFKP interacting proteins. ResultsWe found that PFKP was highly expressed in NSCLC and was related to poor patient survival. Knockdown of PFKP significantly inhibited cell proliferation, colony formation, invasion, and migration of NSCLC cells. Mechanistically, we found that PFKP can directly bind with AXL and promote its phosphorylation at Y779, thus activating the AXL signaling pathway and promoting MET phosphorylation. In addition, several glycolysis, glutaminolysis, and TCA cycle proteins were downregulated following PFKP silencing. ConclusionsThese data demonstrate that PFKP, beyond its known role in glycolysis, also has a distinct non-metabolic function in affecting lung cancer progression by directly interacting with the AXL-MET axis, thus indicating a potential therapeutic target for lung cancer.

cancer biology↗

LDL-Binding IL-10 Reduces Vascular Inflammation in Atherosclerotic Mice

Atherosclerosis is a chronic inflammatory disease associated with the accumulation of low-density lipoprotein (LDL) in arterial walls. Higher levels of the anti-inflammatory cytokine IL-10 in serum are correlated with reduced plaque burden. However, cytokine therapies have not translated well to the clinic, partially due to their rapid clearance and pleiotropic nature. Here, we engineered IL-10 to overcome these challenges by hitchhiking on LDL to atherosclerotic plaques. Specifically, we constructed fusion proteins in which one domain is IL-10 and the other is an antibody fragment (Fab) that binds to protein epitopes of LDL. In murine models of atherosclerosis, we show that systemically administered Fab-IL-10 constructs bind circulating LDL and traffic to atherosclerotic plaques. One such construct, 2D03-IL-10, significantly reduces aortic immune cell infiltration to levels comparable to healthy mice, whereas non-targeted IL-10 has no therapeutic effect. Mechanistically, we demonstrate that 2D03-IL-10 preferentially associates with foamy macrophages and reduces pro-inflammatory activation markers. This platform technology can be applied to a variety of therapeutics and shows promise as a potential targeted anti-inflammatory therapy in atherosclerosis.

bioengineering↗

Single-nucleus Multiomic Analyses Identifies Gene Regulatory Dynamics of Phenotypic Modulation in Human Aneurysmal Aortic Root

Aortic root aneurysm is a potentially life-threatening condition that may lead to aortic rupture and is often associated with genetic syndromes, such as Marfan syndrome (MFS). Although studies with MFS animal models have provided valuable insights into the pathogenesis of aortic root aneurysms, our understanding of the transcriptomic and epigenomic landscape in human aortic root tissue remains incomplete. This knowledge gap has impeded the development of effective targeted therapies. Here, this study performs the first integrative analysis of single-nucleus multiomic (gene expression and chromatin accessibility) and spatial transcriptomic sequencing data of human aortic root tissue under healthy and MFS conditions. Cell-type-specific transcriptomic and cis-regulatory profiles in the human aortic root are identified. Regulatory and spatial dynamics during phenotypic modulation of vascular smooth muscle cells (VSMCs), the cardinal cell type, are delineated. Moreover, candidate key regulators driving the phenotypic modulation of VSMC, such as FOXN3, TEAD1, BACH2, and BACH1, are identified. In vitro experiments demonstrate that FOXN3 functions as a novel key regulator for maintaining the contractile phenotype of human aortic VSMCs through targeting ACTA2. These findings provide novel insights into the regulatory and spatial dynamics during phenotypic modulation in the aneurysmal aortic root of humans.

pathology↗

Study of Impacts of Two Types of Cellular Aging on the Yeast Bud Morphogenesis

Understanding the mechanisms of cellular aging processes is crucial for attempting to extend organismal lifespan and for studying age-related degenerative diseases. Yeast cells divide through budding, providing a classical biological model for studying cellular aging. With their powerful genetics, relatively short lifespan and well-established signaling pathways also found in animals, yeast cells offer valuable insights into the aging process. Recent experiments suggested the existence of two aging modes in yeast characterized by nucleolar and mitochondrial declines, respectively. In this study, by analyzing experimental data it was shown that cells evolving into those two aging modes behave differently when they are young. While buds grow linearly in both modes, cells that consistently generate spherical buds throughout their lifespan demonstrate greater efficacy in controlling bud size and growth rate at young ages. A three-dimensional chemical-mechanical model was developed and used to suggest and test hypothesized mechanisms of bud morphogenesis during aging. Experimentally calibrated simulations showed that tubular bud shape in one aging mode could be generated by locally inserting new materials at the bud tip guided by the polarized Cdc42 signal during the early stage of budding. Furthermore, the aspect ratio of the tubular bud could be stabilized during the late stage, as observed in experiments, through a reduction on the new cell surface material insertion or an expansion of the polarization site. Thus model simulations suggest the maintenance of new cell surface material insertion or chemical signal polarization could be weakened due to cellular aging in yeast and other cell types. Significance StatementAging yeast exhibits two modes with different bud shapes. Experimental data analysis reveals that control of growth rate and bud size is more robust in cells aging in a spherical budding mode than in cells aging in a tubular budding mode. A computational model was developed and used in combination with experiments to test the hypothesized mechanisms underlying different types of budding in aging cells. Model simulations suggest that localized growth is sufficient to generate tubular budding and its aspect ratio can be stabilized through the regulation of chemical signals with an expanding polarization site or a decline on the new cell surface material insertion. Proposed mechanisms of morphological changes in aging yeast can be present in other cell types.

biophysics↗

Active filtering of sequences of neural activity by recurrent circuits of sensory cortex

Recurrent neural networks can generate dynamics, but in sensory cortex it has been unclear if any dynamic processing is supported by the dense recurrent excitatory-excitatory network. Here we show a new role for recurrent connections in mouse visual cortex: they support powerful dynamical computations, but by filtering sequences of input instead of generating sequences. Using two-photon optogenetics, we measure neural responses to natural images and play them back, finding responses are boosted when inputs are played back during the correct movie dynamic context-- when the preceding sequence corresponds to natural vision. This sequence selectivity depends on a network mechanism: earlier input patterns produce responses in other local neurons, which interact with later input patterns. We confirm this mechanism by designing sequences of inputs that are boosted or attenuated by the network. These data suggest recurrent cortical connections perform predictive processing, encoding the statistics of the natural world in input-output transformations.

neuroscience↗

Spherical Echo-Planar Time-resolved Imaging (sEPTI) for rapid 3D quantitative T2* and Susceptibility imaging

PurposeTo develop a 3D spherical EPTI (sEPTI) acquisition and a comprehensive reconstruction pipeline for rapid high-quality whole-brain submillimeter T2* and QSM quantification. MethodsFor the sEPTI acquisition, spherical k-space coverage is utilized with variable echo-spacing and maximum kx ramp-sampling to improve efficiency and incoherency when compared to existing EPTI approaches. For reconstruction, an iterative rank-shrinking B0 estimation and odd-even high-order phase correction algorithms were incorporated into the reconstruction to better mitigate artifacts from field imperfections. A physics-informed unrolled network was utilized to boost the SNR, where 1-mm and 0.75-mm isotropic whole-brain imaging were performed in 45 and 90 seconds, respectively. These protocols were validated through simulations, phantom, and in vivo experiments. Ten healthy subjects were recruited to provide sufficient data for the unrolled network. The entire pipeline was validated on additional 5 healthy subjects where different EPTI sampling approaches were compared. Two additional pediatric patients with epilepsy were recruited to demonstrate the generalizability of the unrolled reconstruction. ResultssEPTI achieved 1.4 x faster imaging with improved image quality and quantitative map precision compared to existing EPTI approaches. The B0 update and the phase correction provide improved reconstruction performance with lower artifacts. The unrolled network boosted the SNR, achieving high-quality T2* and QSM quantification with single average data. High-quality reconstruction was also obtained in the pediatric patient using this network. ConclusionsEPTI achieved whole-brain distortion-free multi-echo imaging and T2* and QSM quantification at 0.75 mm in 90 seconds which has the potential to be useful for wide clinical applications.

bioengineering↗

Plant-on-a-chip: continuous, soilless electrochemical monitoring of salt uptake and tolerance among different genotypes of tomato

Tomatoes (Solanum lycopersicum), a high-value crop, exhibit a unique relationship with salt, where increased levels of NaCl can enhance flavor, aroma and nutritional quality but can cause oxidative damage and reduce yields. A drive for larger, better-looking tomatoes has reduced the importance of salt sensitivity, a concern considering that the sodium content of agricultural land is increasing over time. Currently, there are no simple ways of comparing salt tolerance between plants, where a holistic approach looking at [Na+] throughout the plant typically involves destructive, single time point measurements or expensive imaging techniques. Finding methods that collect rapid information in real time could improve the understanding of salt resistance in the field. Here we investigate the uptake of NaCl by tomatoes using TETRIS (Time-resolved Electrochemical Technology for plant Root environment In-situ chemical Sensing), a platform used to measure chemical signals in the root area of living plants. Low-cost, screen-printed electrochemical sensors were used to measure changes in salt concentration via electrical impedance measurements, facilitating the monitoring of the uptake of ions by roots. We not only demonstrated differences in the rate of uptake of NaCl between tomato seedlings under different growth conditions, but also showed differences in uptake between varieties of tomato with different NaCl sensitivities and the relatively salt-resistant "wild tomato" (Solanum pimpinellifolium) sister species. Our results suggest that TETRIS could be used to ascertain physiological traits of salt resistance found in adult plants but at the seedling stage of growth. This extrapolation, and the possibility to multiplex and change sensor configuration, could enable high-throughput screening of many hundreds or thousands of mutants or varieties.

bioengineering↗

A 20-year time-series of a freshwater lake reveals seasonal dynamics and environmental drivers of viral diversity, ecology, and evolution

Long-term ecological studies are powerful tools to investigate microbiomes and ecosystem change but have mostly ignored viruses. Here, we leveraged a 20-year time-series of a freshwater lake to characterize 1.3 million viral genomes over time, seasonality, and environmental factors. We identified 578 auxiliary metabolic gene (AMG) clusters representing over 150,000 AMGs, the most abundant of which, including psbA for photosynthesis, pmoC for methane oxidation, and katG for hydrogen peroxide decomposition, were consistently represented in viruses across decades and seasons. We observed positive associations and niche differentiation between virus-host pairs during seasonal change including in keystone taxa, Cyanobacteria, methanotrophs, and Nanopelagicales. Environmental constraints, specifically inorganic carbon and ammonium influenced viral abundances over time, and highlighted roles of viruses in both "top-down" and "bottom-up" interactions. Key evolutionary processes shaping gene and genome-wide selection included favored fitness genes, reduced genomic heterogeneity, and dominant sub-populations carrying specific genes. Overall, our study advances understanding of diversity, ecological dynamics, and evolutionary trajectories of viruses in Earths microbiomes and ecosystems.

microbiology↗

Oxidative stress induces release of mitochondrial DNA into the extracellular space in human placental villous trophoblast BeWo cells

Circulating cell-free mitochondrial DNA (ccf-mtDNA) is an indicator of cell death, inflammation, and oxidative stress. ccf-mtDNA differs in pregnancies with placental dysfunction from healthy pregnancies and the direction of this difference depends on gestational age and method of mtDNA quantification. Reactive oxygen species (ROS) trigger release of mtDNA from non-placental cells; yet it is unknown whether trophoblast cells release mtDNA in response to oxidative stress, a common feature of pregnancies with placental pathology. We hypothesized that oxidative stress would induce cell death and release of mtDNA from trophoblast cells. BeWo cells were treated with antimycin A (10-320 M) or rotenone (0.2-50 M) to induce oxidative stress. A multiplex real-time quantitative PCR (qPCR) assay was used to quantify mtDNA and nuclear DNA in membrane bound, non-membrane bound, and vesicular-bound forms in cell culture supernatants and cell lysates. Treatment with antimycin A increased ROS (p<0.0001), induced cell necrosis (p=0.0004) but not apoptosis (p=0.6471) and was positively associated with release of membrane-bound and non-membrane bound mtDNA (p<0.0001). Antimycin A increased mtDNA content in exosome-like extracellular vesicles (vesicular-bound form; p=0.0019) and reduced autophagy marker expression (LC3A/B, p=0.0002; p62, p<0.001). Rotenone treatment did not influence mtDNA release or cell death (p>0.05). Oxidative stress induces release of mtDNA into the extracellular space and causes non-apoptotic cell death and a reduction in autophagy markers in BeWo cells, an established in vitro model of human trophoblast cells. Intersection between autophagy and necrosis may mediate the release of mtDNA from the placenta in pregnancies exposed to oxidative stress. NEW & NOTEWORTHYThis is the first study to test whether trophoblast cells release mitochondrial DNA in response to oxidative stress and to identify mechanisms of release and biological forms of mtDNA from this cellular type. This research identifies potential cellular mechanisms that can be used in future investigations to establish the source and biomarker potential of circulating mitochondrial DNA in preclinical experimental models and humans.

cell biology↗

Translational T-box riboswitches bind tRNA by modulating conformational flexibility

T-box riboswitches, paradigmatic non-coding RNA elements involved in genetic regulation in most Gram-positive bacteria, are adept at monitoring amino acid metabolism through direct interactions with specific tRNAs. T-box riboswitches assess tRNA aminoacylation status, subsequently regulating the transcription or translation of downstream genes involved in amino acid metabolism. Here we present single-molecule FRET studies of the Mycobacterium tuberculosis IleS T-box riboswitch, a model of T-box translational regulation. The data supports a two-step binding model where the tRNA anticodon is recognized first, followed by interactions with the NCCA sequence. Specifically, after anticodon recognition, tRNA in the partially bound state can transiently dock into the discriminator domain, resembling the fully bound state, even in the absence of the tRNA NCCA-discriminator interactions. Establishment of the NCCA-discriminator interactions significantly stabilizes the fully bound state. Collectively, the data suggests higher conformational flexibility in translation-regulating T-box riboswitches, compared to transcription-regulating ones, and supports a conformational selection model for NCCA recognition. Furthermore, it was found that the conserved RAG sequence is pivotal in maintaining specific interactions with the tRNA NCCA sequence by preventing sampling of an aberrant conformational state, while Stem IIA/B-linker interactions impact the conformational dynamics and the stability of both the partially bound and fully bound states. The present study provides a critical kinetic basis for how specific sequences and structural elements in T-box riboswitches enable the binding efficiency and specificity required to achieve gene regulation.

biophysics↗

Integrative Omics Uncovers Low Tumorous Magnesium Content as A Driver Factor of Colorectal Cancer

Magnesium (Mg) deficiency is associated with increased risk and malignancy of colorectal cancer (CRC), yet the underlying mechanisms remain elusive. Here we used genomic, proteomic, and phosphoproteomic data to elucidate the impact of Mg deficiency on CRC. Genomic analysis identified 160 genes with higher mutation frequencies in Low-Mg tumors, including key driver genes such as KMT2C and ERBB3. Unexpectedly, initiation driver genes of CRC, such as TP53 and APC, displayed higher mutation frequencies in High-Mg tumors. Additionally, proteomics and phosphoproteomics indicated that low tumorous Mg content may activate epithelial-mesenchymal transition (EMT) by modulating inflammation or remodeling the phosphoproteome of cancer cells. Notably, we observed a negative correlation between the phosphorylation of DBN1 at S142 (DBN1S142p) and Mg content. A mutation in S142 to D (DBN1S142D) mimicking DBN1S142p upregulated MMP2 and enhanced cell migration, while treatment with MgCl2 reduced DBN1S142p, thereby reversing this phenotype. Mechanistically, Mg2+ attenuated the DBN1-ACTN4 interaction by decreasing DBN1S142p, which, in turn, enhanced the binding of ACTN4 to F-actin and promoted F-actin polymerization, ultimately reducing MMP2 expression. These findings shed new light on the crucial role of Mg deficiency in CRC progression and suggest that Mg supplementation may offer a promising preventive and therapeutic strategy for CRC.

cancer biology↗

Correlating fluorescence microscopy, optical and magnetic tweezers to study single chiral biopolymers, tested on DNA plectoneme formation dynamics

Biopolymer topology is critical for determining interactions inside cell environments, exemplified by DNA where its response to mechanical perturbation is as important as biochemical properties to its cellular roles. The dynamic structures of chiral biopolymers exhibit complex dependence with extension and torsion, however the physical mechanisms underpinning the emergence of structural motifs upon physiological twisting and stretching are poorly understood due to technological limitations in correlating force, torque and spatial localization information. We present COMBI-Tweez (Combined Optical and Magnetic BIomolecule TWEEZers), a transformative tool that overcomes these challenges by integrating optical trapping, time-resolved electromagnetic tweezers, and fluorescence microscopy, demonstrated on single DNA molecules, that can controllably form and visualise higher order structural motifs including plectonemes. This technology combined with cutting-edge MD simulations provides quantitative insight into complex dynamic structures relevant to DNA cellular processes and can be adapted to study a range of filamentous biopolymers.

biophysics↗

CREB activation drives acinar to ductal reprogramming and promote pancreatic cancer progression in animal models of alcoholic chronic pancreatitis

BACKGROUND & AIMSChronic alcoholism often leads to pancreatitis, which exacerbates pancreatic damage through acinar cell injury, fibrotic inflammation and activates AKT/mTOR/cyclic adenosine monophosphate response element binding protein 1 (CREB) signaling axis. However, the molecular interplay between oncogenic KrasG12D/+(Kras*) and CREB in promoting pancreatic cancer progression under chronic inflammation remains poorly understood. METHODSExperimental alcoholic chronic pancreatitis (ACP) induction was established in multiple mouse models, with euthanasia during the recovery stage to evaluate tumor latency. CREB was selectively deleted (Crebfl/fl) in Ptf1aCreERTM/+;LSL-KrasG12D/+(KC) genetic mouse models (KCC-/-). Pancreata from Ptf1aCreERTM/+, KC, and KCC-/- mice were analyzed using histological profiling, western blotting, phosphokinase array, and quantitative PCR. Single-cell RNA sequencing was performed in ACP-induced KC mice. Lineage tracing analysis in YFP reporter mice and acinar cell explant cultures analysis were also conducted. RESULTSACP induction in KC mice significantly impaired pancreas repair mechanism. Acinar cell-derived ductal lesions demonstrated sustained CREB hyperactivation in acinar-to-ductal metaplasia (ADM)/pancreatic intraepithelial neoplasia (PanIN) lesions associated with pancreatitis and pancreatic cancer. Persistent CREB activity reprogrammed acinar cells, and increased profibrotic inflammation. Notably, acinar specific Creb deletion in ACP induced models suppressed high grade PanIN development, restrained tumor progression, and improved acinar cell function. CONCLUSIONSOur findings demonstrate that CREB and Kras* promote irreversible ADM, accelerating pancreatic cancer progression with ACP. Targeting CREB may present a promising strategy to mitigate inflammation-driven pancreatic tumorigenesis.

cancer biology↗

Somatic cancer driver mutations are enriched and associated with inflammatory states in Alzheimer's disease microglia

Alzheimers disease (AD) is an age-associated neurodegenerative disorder characterized by progressive neuronal loss and pathological accumulation of the misfolded proteins amyloid-{beta} and tau1,2. Neuroinflammation mediated by microglia and brain-resident macrophages plays a crucial role in AD pathogenesis1-5, though the mechanisms by which age, genes, and other risk factors interact remain largely unknown. Somatic mutations accumulate with age and lead to clonal expansion of many cell types, contributing to cancer and many non-cancer diseases6,7. Here we studied somatic mutation in normal aged and AD brains by three orthogonal methods and in three independent AD cohorts. Analysis of bulk RNA sequencing data from 866 samples from different brain regions revealed significantly higher ([~]two-fold) overall burdens of somatic single-nucleotide variants (sSNVs) in AD brains compared to age-matched controls. Molecular-barcoded deep (>1000X) gene panel sequencing of 311 prefrontal cortex samples showed enrichment of sSNVs and somatic insertions and deletions (sIndels) in cancer driver genes in AD brain compared to control, with recurrent, and often multiple, mutations in genes implicated in clonal hematopoiesis (CH)8,9. Pathogenic sSNVs were enriched in CSF1R+ microglia of AD brains, and the high proportion of microglia (up to 40%) carrying some sSNVs in cancer driver genes suggests mutation-driven microglial clonal expansion (MiCE). Analysis of single-nucleus RNA sequencing (snRNAseq) from temporal neocortex of 62 additional AD cases and controls exhibited nominally increased mosaic chromosomal alterations (mCAs) associated with CH10,11. Microglia carrying mCA showed upregulated pro-inflammatory genes, resembling the transcriptomic features of disease-associated microglia (DAM) in AD. Our results suggest that somatic driver mutations in microglia are common with normal aging but further enriched in AD brain, driving MiCE with inflammatory and DAM signatures. Our findings provide the first insights into microglial clonal dynamics in AD and identify potential new approaches to AD diagnosis and therapy.

genomics↗

A spectrum of altered non-rapid eye movement sleep in schizophrenia

BackgroundMultiple facets of sleep neurophysiology, including electroencephalography (EEG) metrics such as non-rapid eye movement (NREM) spindles and slow oscillations (SO), are altered in individuals with schizophrenia (SCZ). However, beyond group-level analyses which treat all patients as a unitary set, the extent to which NREM deficits vary among patients is unclear, as are their relationships to other sources of heterogeneity including clinical factors, illness duration and ageing, cognitive profiles and medication regimens. Using newly collected high density sleep EEG data on 103 individuals with SCZ and 68 controls, we first sought to replicate our previously reported (Kozhemiako et. al, 2022) group-level mean differences between patients and controls (original N=130). Then in the combined sample (N=301 including 175 patients), we characterized patient-to-patient variability in NREM neurophysiology. ResultsWe replicated all group-level mean differences and confirmed the high accuracy of our predictive model (Area Under the ROC Curve, AUC = 0.93 for diagnosis). Compared to controls, patients showed significantly increased between-individual variability across many (26%) sleep metrics, with patterns only partially recapitulating those for group-level mean differences. Although multiple clinical and cognitive factors were associated with NREM metrics including spindle density, collectively they did not account for much of the general increase in patient-to-patient variability. Medication regimen was a greater (albeit still partial) contributor to variability, although original group mean differences persisted after controlling for medications. Some sleep metrics including fast spindle density showed exaggerated age-related effects in SCZ, and patients exhibited older predicted biological ages based on an independent model of ageing and the sleep EEG. ConclusionWe demonstrated robust and replicable alterations in sleep neurophysiology in individuals with SCZ and highlighted distinct patterns of effects contrasting between-group means versus within-group variances. We further documented and controlled for a major effect of medication use, and pointed to greater age-related change in NREM sleep in patients. That increased NREM heterogeneity was not explained by standard clinical or cognitive patient assessments suggests the sleep EEG provides novel, nonredundant information to support the goals of personalized medicine. Collectively, our results point to a spectrum of NREM sleep deficits among SCZ patients that can be measured objectively and at scale, and that may offer a unique window on the etiological and genetic diversity that underlies SCZ risk, treatment response and prognosis.

neuroscience↗

FGF12 Modulates Cardiomyocyte Hypertrophy by Inhibiting GATA4-ERK1/2 Phosphorylation Through Altered Intracellular Localization

BackgroundHypertrophic cardiomyopathy (HCM) is a heritable pathological condition resulting from mutations in sarcomere-related proteins, leading to severe structural abnormalities without effective treatment options. Although reduced fibroblast growth factor 12(FGF12) expression is observed in HCM patients, its functional role remains unclear. MethodsEmploying immunoprecipitation (IP)-mass spectrometry (MS) and CUT&Tag sequencing, we investigated FGF12-interacting proteins in myocardial samples from healthy volunteers and HCM patients. CRISPR-Cas9 was utilized to explore the function and interaction partners of FGF12 in cardiomyocytes induced from human pluripotent stem cells (hiPSCs-CMs), other cell lines, and mouse models (MYH7R403Q and MYBPC3c.790G>A, transverse aortic constriction (TAC)). During hypertrophy, FGF12 localizes intranuclearly, prompting investigations into its binding to gene promoter regions through CUT&Tag sequencing and dual-luciferase experiments using myocardial tissues from patients. The beating frequency of hiPS-CMs was assessed using the CardioExcyte 96 real-time label-free cardiomyocyte functional analysis system. ResultsFGF12 was found to associate with proteins involved in energy metabolism, predominantly localizing to the perinuclear space under physiological conditions but shifting into the nucleus of hypertrophic cardiomyocytes. Co-IP-MS revealed significant interactions between FGF12 and metabolism-associated proteins, particularly GATA binding protein 4 (GATA4) and mitogen-activated protein kinase 1/3 (MAPK1/3) in the perinuclear space. In a hypertrophic state, FGF12 bound to the GATA4 promoter region, increasing its expression upon nuclear translocation. Both in vitro and in vivo models demonstrated that FGF12 interaction with GATA4 inhibited GATA4 and MAPK1/3 phosphorylation, inducing the expression of hypertrophy-associated genes. Overexpression of FGF12-NLS-del (nuclear localization signal deletion) resulted in decreased GATA4 phosphorylation, suggesting inhibition in the perinuclear region. ConclusionsThis study elucidates a pathological mechanism of HCM involving FGF12, where its nuclear localization enhances phosphorylation, GATA4 expression, and activation of the ERK1/2-pGATA4 pathway genes associated with hypertrophy. Beyond advancing our understanding of HCM, these findings propose FGF12 as a potential therapeutic target for HCM, warranting further exploration to potentially alleviate this condition affecting millions of individuals.

molecular biology↗

Understanding how genetically encoded tags affect phase separation by Heterochromatin Protein HP1α

Liquid-liquid phase separation (LLPS) is driven by weak multi-valent interactions. Such interactions can result in the formation of puncta in cells and droplets in vitro. The heterochromatin protein HP1 forms droplets with chromatin in vitro and is found in puncta in cells. A common approach to visualize the dynamics of HP1 in cells is to genetically encode fluorescent tags on the protein. HP1 modified with tags such as GFP has been shown to localize to dynamic puncta in vivo. However, whether tagged HP1 retains its intrinsic phase separation properties has not been systematically studied. Here, using different C-terminal tags (AID-sfGFP, mEGFP, and UnaG), we assessed how tag size and linker length affected the phase separation ability of HP1 with DNA in vitro. We found that the AID-sfGFP tag (52 kDa) promoted HP1 phase-separation, possibly driven by the highly disordered AID degron. The mEGFP tag (27 kDa) inhibited phase-separation by HP1, whereas an UnaG tag (13 kDa) with a 16 amino acid linker showed minimal perturbation. The UnaG tag can thus be used in cellular studies of HP1 to better correlate in vitro and in vivo studies. To test if cellular crowding overcomes the negative effects of large tags in vivo, we used polyethylene glycol (PEG) to mimic crowding in vitro. We found that addition of 10% PEG8000 or PEG4000 enables phase separation by GFP-tagged HP1 at comparable concentrations as untagged HP1. However, these crowding agents also substantially dampened the differences in phase-separation between wild-type and mutant HP1 proteins. PEG further drove phase-separation of Maltose Binding Protein (MBP), a tag often used to solubilize other proteins. These results suggest that phase-separation of biological macromolecules with PEG should be interpreted with caution as PEG-based crowding agents may change the types of interactions made within the phases.

biophysics↗