Biology subjects

Zhang, C.

Publications and source records attributed to Zhang, C..

At least 361 records · Page 20Linked to original sources

bioRxiv2024

RNA secondary structure ensemble mapping in a living cell identifies conserved RNA regulatory switches and thermometers

RNA molecules can populate ensembles of alternative structural conformations, but comprehensively mapping RNA conformational landscapes within living cells presents significant challenges and has, as such, so far remained elusive. Here, we generated the first transcriptome-scale maps of RNA secondary structure ensembles in a living cell, using Escherichia coli as a model. Our analysis uncovered features of structurally-dynamic regions, as well as the existence of hundreds of highly-conserved bacterial RNA structural elements. Conditional structure mapping revealed extensive restructuring of RNA ensembles during cold shock, leading to the discovery of several novel RNA thermometers in the 5' UTRs of the cspG, cspI, cpxP and lpxP mRNAs. We mechanistically characterized how these thermometers switch structure in response to cold shock and revealed the cspE chaperone-mediated regulation of lpxP. Collectively, this work reveals a previously unappreciated complexity of RNA structural dynamics in living cells, and it provides a key resource to significantly accelerate the discovery of regulatory RNA switches.

molecular biology↗

bioRxiv2024

Preventive Effects of Pomegranate Seed Oil on Transient Middle Cerebral Artery Occlusion via the Keap1/Nrf2/NQO1 Pathway in the rats Cortex

Ischemic stroke remains a pressing challenge that needs to be solved. Energy metabolic failure is a critical factor contributing to mitochondrial dysfunction and oxidative stress in the pathogenesis of brain ischemia, leading to the generation of excessive reactive oxygen species. Pomegranate seed oil (PSO) exhibits antioxidant properties; however, its protective effects against cerebral ischemia/reperfusion injury and the underlying mechanisms remain unclear. In this study, a transient middle cerebral artery occlusion (tMCAO) rat model was employed to simulate cerebral ischemia/reperfusion injury. We investigated the mechanisms by which different concentrations of PSO modulate oxidative damage caused by cerebral ischemia/reperfusion injury through the Keap1/Nrf2/NQO1 pathway in cortex. SD male rats were randomly divided into four groups: Control, tMCAO+NaCl, tMCAO+LO (low concentration of PSO), tMCAO+MO (medium concentration of PSO), and tMCAO+HO (high concentration of PSO). Our findings suggest that low concentration of PSO exerts neuroprotective effects by activating Nrf2 and NQO1, thereby reducing oxidative stress. Furthermore, LO significantly improved neurological scores and reduced neuronal edema. Additionally, the results demonstrated an increase in superoxide dismutase (SOD) levels and a decrease in malondialdehyde (MDA) levels. In contrast, MO and HO exhibited suboptimal effects. To sum up, these results indicate that PSO activates neuroprotective pathways against oxidative stress following cerebral ischemia/reperfusion injury via the Keap1/Nrf2/NQO1 pathway, providing novel insights into potential preventive therapies for cerebral ischemia/reperfusion.

neuroscience↗

bioRxiv2024

Haplotype-resolved assemblies provide insights into genomic makeup of the oldest grapevine cultivar (Munage) in Xingjiang

AbstractsMunage, an ancient grape variety that has been cultivated for thousands of years in Xinjiang, China, is recognized for its exceptional fruit traits. There are two main types of Munage: white fruit (WM) and red fruit (RM). However, the lack of a high-quality genomic resources has impeded effective breeding and restricted the potential for expanding these varieties to other growing regions. In this study, we assembled haplotype-resolved genome assemblies for WM and RM, alongside integrated whole genome resequencing (WGS) data and transcriptome data to illuminate specific mutations and associated genes in Munake and the genes associated with fruit color traits. Selective analysis between Munage clones and Eurasian grapes suggested that adaptive selection exists in Munage grapes, with genes enriched in processes including cell maturation, plant epidermal cell differentiation, and root epidermal cell differentiation. The study examined the mutations within Munage grapes and found that the genes PMAT2 on chromosome 12 and MYB123 on chromosome 13 are likely responsible for color variation in RM. These findings provide crucial genetic resources for investigating the genetics of the ancient Chinese grape variety, Munage, and will facilitate the genetic improvement in grapevine.

genomics↗

bioRxiv2024

A brain-body feedback loop driving HPA-axis dysfunction in breast cancer

Breast cancer patients often exhibit disrupted circadian rhythms in circulating glucocorticoids (GCs), such as cortisol. This disruption correlates with reduced quality of life and higher cancer mortality1-3. The exact cause of this phenomenon -- whether due to treatments, stress, age, co-morbidities, lifestyle factors, or the cancer itself remains unclear. Here, we demonstrate that primary breast cancer alone blunts host GC rhythms by disinhibiting neurons in the hypothalamus, and that circadian phase-specific neuromodulation of these neurons can attenuate tumor growth by enhancing anti-tumor immunity. We find that mice with mammary tumors exhibit blunted GC rhythms before tumors are palpable, alongside increased activity in paraventricular hypothalamic neurons expressing corticotropin-releasing hormone (i.e., PVNCRH neurons). Tumor-bearing mice have fewer inhibitory synapses contacting PVNCRH neurons and reduced miniature inhibitory post-synaptic current (mIPSC) frequency, leading to net excitation. Tumor-bearing mice experience impaired negative feedback on GC production, but adrenal and pituitary gland functions are largely unaffected, indicating that alterations in PVNCRH neuronal activity are likely a primary cause of hypothalamic-pituitary-adrenal (HPA) axis dysfunction in breast cancer. Using chemogenetics (hM3Dq) to stimulate PVNCRH neurons at different circadian phases, we show that stimulation just before the light-to-dark transition restores normal GC rhythms and reduces tumor progression. These mice have significantly more effector T cells (CD8+) within the tumor than non-stimulated controls, and the anti-tumor effect of PVNCRH neuronal stimulation is absent in mice lacking CD8+ T cells. Our findings demonstrate that breast cancer distally regulates neurons in the hypothalamus that control output of the HPA axis and provide evidence that therapeutic targeting of these neurons could mitigate tumor progression.

neuroscience↗

bioRxiv2024

G3BP1 Maintains Vascular Endothelial Barrier Integrity by Negatively Regulating the MYD88-ARNO-ARF6 Signaling Pathway

Endothelial permeability is essential for vascular function. This process is regulated by intercellular junctions, including adherens junctions (AJs) and tight junctions (TJs), which form the endothelial barrier and dynamically connect adjacent cells. However, the mechanisms that control endothelial permeability are not fully understood. We investigated the role of the RNA-binding protein G3BP1 in regulating endothelial permeability. We examined the effects of Loss of g3bp1 in conditional knockout mice and primary human HUVEC cells. We analyzed endothelial barrier integrity and permeability, focusing on AJ and TJ expression, under both normal and LPS-induced inflammatory conditions. Loss of g3bp1 in vascular endothelial cells decreased AJ and TJ expression, compromised barrier integrity, and increased permeability. These effects were exacerbated under LPS-induced inflammatory conditions. Loss of g3bp1 also increased the expression of MYD88, ARNO, and ARF6, and enhanced ARF6 activity. Mechanistically, G3BP1 bound to and stabilized MYD88 mRNA, negatively regulating the MYD88-ARNO-ARF6 signaling pathway. Inhibiting this pathway by reducing MYD88 or ARF6 expression, or inhibiting ARNO activity, restored AJ/TJ expression and barrier function in G3BP1-deficient models. Our findings identify G3BP1 as a novel regulator of vascular endothelial permeability. G3BP1 acts by negatively regulating the MYD88-ARNO-ARF6 signaling pathway. Targeting G3BP1 may be a potential therapeutic strategy for diseases associated with endothelial barrier dysfunction.

physiology↗

bioRxiv2024

Molecular mechanisms of uric acid transport by the native human URAT1 and its inhibition by anti-gout drugs

Gout, a common and painful disease, stems from hyperuricemia, where elevated blood uric acid levels lead to urate crystal formation in joints and kidneys. The human urate transporter 1 (hURAT1) plays a critical role in urate homeostasis by facilitating urate reabsorption in the renal proximal tubule, making it a key target for gout therapy. Pharmacological inhibition of hURAT1 with drugs such as dotinurad, benzbromarone, lesinurad, and verinurad promotes uric acid excretion and alleviates gout symptoms. Here we present cryo-electron microscopy structures of native hURAT1 bound with these anti-gout drugs in the inward-open state, and with uric acid in inward-open, outward-open, and occluded states. Complemented by mutagenesis and cell-based assays, these structures reveal the mechanisms of uric acid reabsorption and hURAT1 inhibition. Our findings elucidate the molecular basis of uric acid transport and anti-gout medication action, and provide a structural framework for the rational design of next-generation therapies for hyperuricemia and gout.

biochemistry↗

bioRxiv2024

Dynamic cycles between idea generation and evaluation during creative storytelling

Many theories support the notion that creative thinking involves a dynamic transition between idea generation and evaluation, but there is limited evidence of how these two stages interact. The dual process model proposes that spontaneous thinking and deliberate thinking drive these stages and the transitions between them, but there is a debate over whether they operate in parallel or in sequence. To address these gaps, we conducted a functional magnetic resonance imaging (fMRI) study in 41 college students during a creative storytelling task. By analyzing the dynamic brain state, we link the brain states with idea generation and evaluation. The transition patterns between brain states provide evidence for dynamic circulation between idea generation and evaluation during creative storytelling. Using a deep learning approach, we demonstrate an alternating interaction between spontaneous and deliberate thinking, driving the idea generation and evaluation stages and the transitions between them. These findings deepen our understanding of the cognitive and neural mechanisms underlying creative thinking.

neuroscience↗

bioRxiv2024

Pannexin 1 crosstalk with the Hippo pathway in malignant melanoma

In this study, we explored the intricate relationship between Pannexin 1 (PANX1) and the Hippo signaling pathway effector, Yes-associated protein (YAP). Analysis of The Cancer Genome Atlas (TCGA) data revealed a significant positive correlation between PANX1 mRNA and core Hippo components, YAP, TAZ, and Hippo scaffold, IQGAP1, in invasive cutaneous melanoma and breast carcinoma. Furthermore, we demonstrated that PANX1 expression is upregulated in invasive melanoma cell lines and is associated with increased YAP protein levels. Notably, our investigations uncovered a previously unrecognized interaction between endogenous PANX1 and the Hippo scaffold protein IQGAP1 in melanoma cells. Moreover, our findings revealed that IQGAP1 exhibits differential expression in melanoma cells and plays a regulatory role in cellular morphology. Functional studies involving PANX1 knockdown provided compelling evidence that PANX1 modulates YAP protein levels and its co-transcriptional activity in both melanoma and breast carcinoma cells. Importantly, our study showcases the potential therapeutic relevance of targeting PANX1, as pharmacological inhibition of PANX1 using selective FDA-approved inhibitors or PANX1 knockdown reduced YAP abundance in melanoma cells. Furthermore, our Clariom S analysis unveiled key genes implicated in cell proliferation, such as neuroglin1 (NRG1), {beta}-galactoside binding protein, galectin-3 (LGALS3), that are affected in PANX1- deficient cells. In summary, our investigation delves into the intricate interplay between PANX1 and YAP in the context of invasive melanoma, offering valuable insights into potential therapeutic strategies for effective treatment.

cell biology↗

bioRxiv2024

Distinct neural manifolds and critical roles of primate caudate nucleus in multimodal decision-making

Representational redundancy is ubiquitous in the brain with distributed networks encode task variables in a similar way, which may mask the unique roles of each region. Using a multisensory decision paradigm, here we showed that primate caudate nucleus (CN) dramatically differed from decision-related cortices in the reduced low-dimensional neural subspace, although possessing similar choice representations. Specifically, bimodal neural trajectories evolved towards nonvisual (vestibular) in CN, rather than towards visual as in frontal/parietal cortices. This challenges previous hypothesis that striatum mainly reflects cortical decision signals. Following recurrent neural networks simulations suggested that the cortico-subcortical distinction might be due to different intensities of single-modality inputs. We furtherly demonstrated that CN population responses represented the multisensory behavior strategy animal employed within the generalized drift-diffusion framework. Importantly, neural manipulations by unilateral drug injection and microstimulation confirmed CNs causal contributions to multisensory decisions. Overall, our results indicate beyond relay-station in cortico-striatal circuitry, CN plays distinct and critical roles in perceptual decision-making.

neuroscience↗

bioRxiv2024

Single-cell analysis of the somatic mutational landscape in human chondrocytes during aging and in osteoarthritis

Somatic mutation is now recognized as a cause of multiple human diseases other than cancer. Osteoarthritis (OA), a highly prevalent age-related disease, has been associated with increased chromosomal abnormalities in articular cartilage of OA patients. Thus far no systematic attempt has been made to characterize the somatic mutational landscape of chondrocytes during normal aging and in affected cartilage of OA patients. Here we used single-cell whole genome sequencing to quantitatively analyze single-nucleotide variants (SNVs) and small insertions and deletions (InDels) in 100 single chondrocytes isolated from the cartilage of hip femoral heads of 17 subjects aged from 26 to 90 years, including 9 OA patients and 8 non-OA donors. Both SNVs and InDels were found to accumulate with age in chondrocytes with a clock-like mutational signature. Surprisingly, the age-related accumulation rate of these mutations was found to be lower in OA chondrocytes compared with chondrocytes from non-OA control subjects.

genomics↗

bioRxiv2024

Steering cell-state and phenotype transitions by causal disentanglement learning

Understanding and manipulating cell-state and phenotype transitions is essential for advancing biological research and therapeutic treatment. We introduce CauFinder, an advanced framework designed to accurately identify causal regulators of these transitions and further precisely steer such transitions by integrating causal disentanglement modelling with network control based solely on observed data. By leveraging do-calculus and optimizing information flow metrics, CauFinder can distinguish causal factors from spurious ones, ensuring precise control over desired state transitions. One significant advantage of CauFinder is its ability to identify those variables causally affecting the cell-state/phenotype transitions among all observed variables, both theoretically and computationally, leading to the identification of their master regulators when combined with network control. Consequently, by employing a counterfactual algorithm, CauFinder is able effectively to facilitate desirable state transitions or steer these transitional trajectories/paths by modulating these causal drivers. Beyond its theoretical advantages, CauFinder outperforms existing approaches computationally in both simulated and real-world settings. CauFinder is able to not only reveal natural biological transition processes such as (a) cell differentiation, (b) lung adenocarcinoma (LUAD) to lung squamous cell carcinoma (LUSC) transdifferentiation and (c) drug-sensitive to drug-resistant transitions but also identify the causal regulators of their reverse transition processes, such as (A) cell dedifferentiation, (B) LUSC to LUAD transdifferentiation and (C) drug-resistant to drug-sensitive transitions. These findings highlight its superior ability to causally uncover essential regulatory mechanisms and accurately steer cell-state/phenotype transitions, thus providing novel therapeutic strategies.

bioinformatics↗

bioRxiv2024

RAF inhibitors activate the integrated stress response by direct activation of GCN2

Paradoxical RAF activation by chemical RAF inhibitors (RAFi) is a well-understood on-target biological and clinical response. In this study, we show that a range of RAFi drive ERK1/2-independent activation of the Unfolded Protein Response (UPR), including expression of ATF4 and CHOP, that required the translation initiation factor eIF2. RAFi-induced ATF4 and CHOP expression was not reversed by inhibition of PERK, a known upstream activator of the eIF2-dependent Integrated Stress Response (ISR). Rather, we found that RAFi exposure activated GCN2, an alternate eIF2 kinase, leading to eIF2-dependent (and ERK1/2-independent) ATF4 and CHOP expression. The GCN2 kinase inhibitor A-92, GCN2 RNAi, GCN2 knock-out or ISRIB (an eIF2 antagonist) all reversed RAFi-induced expression of ATF4 and CHOP indicating that RAFi require GCN2 to activate the ISR. RAFi also activated full-length recombinant GCN2 in vitro and in cells, generating a characteristic bell-shaped concentration-response curve, reminiscent of RAFi-driven paradoxical activation of WT RAF dimers. Activation of the ISR by RAFi was abolished by GCN2 kinase dead mutations and M802A or M802G gatekeeper mutations, suggesting that RAFi bind directly to the GCN2 kinase domain; this was supported by mechanistic structural models of RAFi interaction with GCN2. Since the ISR is a critical pathway for determining cell survival or death, our observations may be relevant to the clinical use of RAFi, where paradoxical GCN2 activation may be a previously unappreciated off-target effect that may modulate tumour cell responses.

biochemistry↗

bioRxiv2024

Gene Expression Prediction from Histology Images via Hypergraph Neural Networks

Spatial transcriptomics reveals the spatial distribution of genes in complex tissues, providing crucial insights into biological processes, disease mechanisms, and drug development. The prediction of gene expression based on cost-effective histology images is a promising yet challenging field of research. Existing methods for gene prediction from histology images exhibit two major limitations. First, they ignore the intricate relationship between cell morphological information and gene expression. Second, these methods do not fully utilize the different latent stages of features extracted from the images. To address these limitations, we propose a novel hypergraph neural network model, HGGEP, to predict gene expressions from histology images. HGGEP includes a gradient enhancement module to enhance the models perception of cell morphological information. A lightweight backbone network extracts multiple latent stage features from the image, followed by attention mechanisms to refine the representation of features at each latent stage and capture their relations with nearby features. To explore higher-order associations among multiple latent stage features, we stack them and feed into the hypergraph to establish associations among features at different scales. Experimental results on multiple datasets from disease samples including cancers and tumor disease, demonstrate the superior performance of our HGGEP model than existing methods. Key PointsWe develop a novel histology image-based gene prediction model named HGGEP, which demonstrates high accuracy and robust performance. To reveal the intricate relationship between cell morphology and gene expression in images, we propose a gradient enhancement module, which effectively improves the models capability in perceiving cell morphology in images. HGGEP includes a hypergraph module that efficiently models higher-order associations among features across multiple latent stages, resulting in significant performance improvement.

bioinformatics↗

bioRxiv2024

Manipulation of the microRNA172 - AP2L2 interaction provides precise control of wheat and triticale plant height

The REDUCED HEIGHT (RHT) dwarfing alleles Rht-B1b and Rht-D1b were essential in the "Green Revolution" to optimize wheat plant height and increase grain yield. However, those alleles reduce coleoptile length limiting sowing depth, which triggered the search for alternative dwarfing genes. In this study, we engineered the interaction between miR172 and AP2L2 genes to fine-tune wheat and triticale plant height without affecting coleoptile and first-leaf length.

plant biology↗

bioRxiv2024

Salidroside Mitigates Malignant Arrhythmias by Restoring Sodium Channel Function During Ultra-Acute Myocardial Infarction

BackgroundThe ultra-acute phase (Phase 1a) of acute myocardial infarction (AMI) is marked by a high incidence of malignant arrhythmias, often occurring during the prehospital period. Currently, there are no effective treatment options available for managing these arrhythmias at this early stage. Methods and ResultsUsing dual-channel optical mapping, we simultaneously recorded membrane potentials and calcium transients during acute myocardial infarction. Calcium transient duration maps accurately localized the infarcted region, and action potential activation time maps revealed conduction heterogeneity in the infarcted zone. Patch-clamp recordings showed that Salidroside (Sal) (1 {micro}g/mL) significantly increased sodium current density from -59.27 {+/-} 2.15 pA/pF to -83.46 {+/-} 3.19 pA/pF (P<0.01) and shifted the Nav1.5 activation curve leftward (V1/2 from -37.27 {+/-} 0.5 mV to -44.55 {+/-} 0.7 mV, P<0.01). In rat and rabbit AMI models, Sal pre-treatment reduced conduction heterogeneity and arrhythmia incidence compared to controls. Optical mapping showed improved conduction velocity and uniformity in the Sal group. ConclusionsSal restores electrophysiological function in damaged myocardium by modulating sodium currents, reducing conduction heterogeneity, and decreasing malignant arrhythmia incidence during the ultra-acute phase of AMI. These findings suggest a novel therapeutic strategy for AMI, addressing a critical unmet need in antiarrhythmic therapy. What is New?O_LIThis study identifies Salidroside (Sal) as a novel agent that enhances sodium channel currents (Nav1.5), distinguishing it from traditional antiarrhythmic drugs which primarily target potassium channels or {beta}-adrenergic receptors. Sal improves conduction uniformity in the infarcted myocardium by restoring the electrophysiological function of damaged cardiac cells, eliminating slow conduction pathways, and reducing conduction heterogeneity. C_LIO_LIThis research introduces Sal as a promising candidate for preventing and treating arrhythmias during the critical early stages of MI, potentially improving patient outcomes. Sal administration during the ultra-acute phase (phase 1a) of myocardial infarction (MI) significantly reduces the incidence of malignant arrhythmias, a critical period characterized by high extracellular potassium and increased arrhythmia risk. C_LIO_LIUtilizing calcium transient imaging and optical mapping, this study provides precise localization of ischemic regions and detailed electrophysiological characterization, offering a robust methodology for assessing therapeutic efficacy. C_LI

pharmacology and toxicology↗

bioRxiv2024

Spatial 3D genome organization controls the activity of bivalent chromatin during human neurogenesis

The nuclear genome is spatially organized into a three-dimensional (3D) architecture by physical association of large chromosomal domains with subnuclear compartments including the nuclear lamina at the radial periphery and nuclear speckles within the nucleoplasm1-5. However, how spatial genome architecture regulates human brain development has been overlooked owing to technical limitations. Here, we generate high-resolution maps of genomic interactions with the lamina and speckles in cells of the neurogenic lineage isolated from midgestational human cortex, uncovering an intimate association between subnuclear genome compartmentalization, chromatin state and transcription. During cortical neurogenesis, spatial genome organization is extensively remodeled, relocating hundreds of neuronal genes from the lamina to speckles including key neurodevelopmental genes bivalent for H3K27me3 and H3K4me3. At the lamina, bivalent genes have exceptionally low expression, and relocation to speckles enhances resolution of bivalent chromatin to H3K4me3 and increases transcription >7-fold. We further demonstrate that proximity to the nuclear periphery - not the presence of H3K27me3 - is the dominant factor in maintaining the lowly expressed, poised state of bivalent genes embedded in the lamina. In addition to uncovering a critical role of subnuclear genome compartmentalization in neurogenic transcriptional regulation, our results establish a new paradigm in which knowing the spatial location of a gene is necessary to understanding its epigenomic regulation.

neuroscience↗

bioRxiv2024

A comprehensive analysis of the potential biological functions and prognostic values of SREBF1 for multiple cancer types including colorectal cancer

As an important molecule involved in lipid metabolism, Sterol Regulatory Element-Binding Protein 1 (SREBF1) plays a critical role in governing cellular lipid synthesis and uptake. However, a comprehensive understanding of the biological significance of SREBF1 in pan-cancer remains elusive. In this study, we aimed to comprehensively analyze the functional characteristics of SREBF1 in human cancers, including colorectal cancer (CRC). Our study utilized various databases and tools such as TCGA, GEO, TIMER2.0, GEPIA2.0, UALCAN, and the Human Protein Atlas to examine SREBF1 expression, genetic alterations, immune infiltration, single-cell sequencing, survival analysis, and gene enrichment. The results revealed that the expression of SREBF1 exhibited significant variations across different cancer types, and was closely associated with patient prognosis and immune infiltration. Moreover, the gene function assays indicated SREBF1 significantly affect cell growth and migration. Overall, the findings suggest that SREBF1 could serve as a potential prognostic biomarker and a novel therapeutic target in different cancer types.

cancer biology↗

bioRxiv2024

Role of Kir4.1/Kir5.1 in mediating Angiotensin-II (Ang-II)-induced stimulation of thiazide-sensitive Na-Cl cotransporter.

BackgroundAngiotensin-II (Ang-II) perfusion stimulates Kir4.1/Kir5.1 in the distal-convoluted-tubule (DCT) and thiazide-sensitive Na-Cl-cotransporter (NCC). However, the role of Kir4.1/Kir5.1 in mediating the effect of Ang-II on NCC is not understood. MethodsWe used immunoblotting and patch-clamp-experiments to examine whether Ang-II-induced stimulation of NCC is achieved by activation of Kir4.1/Kir5.1 of the DCT using kidney-renal-tubule-specific AT1aR-knockout (Ks-AT1aR-KO), Ks-Kir4.1-knockout and the corresponding wild-type mice. ResultsAng-II perfusion for 1, 3 and 7 days progressively increased phosphor-NCC (pNCC) and total-NCC (tNCC) expression and the effect of Ang-II-perfusion on pNCC and tNCC was abolished in Ks-AT1aR-KO. Ang-II perfusion for 1-day robustly stimulates Kir4.1/Kir5.1 in the late DCT (DCT2) and to a lesser degree in the early DCT (DCT1), an effect was absent in Ks-AT1aR-KO mice. However, Ang-II perfusion for 7-days did not further stimulate Kir4.1/Kir5.1 in the DCT2 and only modestly increased Kir4.1/Kir5.1-mediated K+ currents in DCT1. Deletion of Kir4.1 not only significantly decreased the expression of pNCC and tNCC but also abolished the effect of 1-day Ang-II perfusion on the expression of phospho-with-no-lysine-kinase-4 (pWNK4), phosphor-ste-20-proline-alanine-rich-kinase (pSPAK), pNCC and tNCC. However, 7-days Ang-II perfusion was still able to significantly stimulate the expression of pSPAK, pWNK4, pNCC and tNCC, and increased thiazide-induced natriuresis in kidney-tubule-specific Kir4.1 knockout (Ks-Kir4.1 KO) mice without obvious changes in K+ channel activity in the DCT. ConclusionsShort-term Ang-II induced stimulation of pWNK4, pSPAK and pNCC depends on Kir4.1/Kir5.1 activity. However, long-term Ang-II is able to directly stimulate pWNK4, pSPAK and pNCC by a Kir4.1/Kir5.1 independent mechanism.

physiology↗