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Science Advances Jun 2024The central nervous system coordinates peripheral cellular stress responses, including the unfolded protein response of the mitochondria (UPR); however, the contexts for...
The central nervous system coordinates peripheral cellular stress responses, including the unfolded protein response of the mitochondria (UPR); however, the contexts for which this regulatory capability evolved are unknown. UPR is up-regulated upon pathogenic infection and in metabolic flux, and the olfactory nervous system has been shown to regulate pathogen resistance and peripheral metabolic activity. Therefore, we asked whether the olfactory nervous system in controls the UPR cell nonautonomously. We found that silencing a single inhibitory olfactory neuron pair, AWC, led to robust induction of UPR and reduction of oxidative phosphorylation dependent on serotonin signaling and -mediated mitophagy. Further, AWC ablation confers resistance to the pathogenic bacteria partially dependent on the UPR transcription factor and fully dependent on mitophagy machinery. These data illustrate a role for the olfactory nervous system in regulating whole-organism mitochondrial dynamics, perhaps in preparation for postprandial metabolic stress or pathogenic infection.
Topics: Animals; Caenorhabditis elegans; Mitophagy; Mitochondria; Caenorhabditis elegans Proteins; Smell; Unfolded Protein Response; Pseudomonas aeruginosa; Ubiquitin-Protein Ligases; Oxidative Phosphorylation; Signal Transduction; Serotonin; Transcription Factors
PubMed: 38905346
DOI: 10.1126/sciadv.adn0014 -
Endocrine Connections Jun 2024Subclinical hypothyroidism (SCH) is closely related to insulin resistance, and thyroid-stimulating hormone (TSH) level is an independent factor for insulin resistance...
Subclinical hypothyroidism (SCH) is closely related to insulin resistance, and thyroid-stimulating hormone (TSH) level is an independent factor for insulin resistance associated with subclinical hypothyroidism. This study aims to explore the effects of TSH levels on insulin signal transduction in adipocytes and to establish the role of endoplasmic reticulum (ER) stress in this process. In this study, the SCH mouse model was established, and 3T3-L1 adipocytes were treated with TSH or tunicamycin (TM), with or without 4-phenylbutyric acid (4-PBA), an inhibitor of ER stress. SCH mice exhibited impaired glucose tolerance, inactivation of the IRS-1/AKT pathway and activation of the IRE1/JNK pathway in adipose tissue, which can all be alleviated by 4-PBA. Supplementation with levothyroxine restored the TSH to normal, alongside alleviated ER stress and insulin resistance in SCH mice, which is characterized by improved glucose tolerance, decreased mRNA expression of IRE1, and decreased phosphorylation of JNK in adipose tissue. In 3T3-L1 adipocytes, TSH induces insulin resistance, leading to a decrease in glucose uptake. This effect is mediated by the downregulation of IRS-1 tyrosine phosphorylation, reduced AKT phosphorylation, and inhibited GLUT4 protein expression. Notably, all these effects can be effectively reversed by 4-PBA. Moreover, TSH induced TNF-α and IL-6 production and upregulated the expression of ER stress markers. Similarly, these changes can be recovered by 4-PBA. These findings indicate that TSH has the capability to induce insulin resistance in adipocytes. The mechanism through which TSH disrupts insulin signal transduction appears to involve the ER stress-JNK pathway.
PubMed: 38904465
DOI: 10.1530/EC-23-0302 -
Platelets Dec 2024Receptor-induced tyrosine phosphorylation of spleen tyrosine kinase (Syk) has been studied extensively in hematopoietic cells. Metabolic mapping and high-resolution mass...
Receptor-induced tyrosine phosphorylation of spleen tyrosine kinase (Syk) has been studied extensively in hematopoietic cells. Metabolic mapping and high-resolution mass spectrometry, however, indicate that one of the most frequently detected phosphorylation sites encompassed S297 (S291 in mice) located within the linker B region of Syk. It has been reported that Protein kinase C (PKC) phosphorylates Syk S297, thus influencing Syk activity. However, conflicting studies suggest that this phosphorylation enhances as well as reduces Syk activity. To clarify the function of this site, we generated Syk S291A knock-in mice. We used platelets as a model system as they possess Glycoprotein VI (GPVI), a receptor containing an immunoreceptor tyrosine-based activation motif (ITAM) which transduces signals through Syk. Our analysis of the homozygous mice indicated that the knock-in platelets express only one isoform of Syk, while the wild-type expresses two isoforms at 69 and 66 kDa. When the GPVI receptor was activated with collagen-related peptide (CRP), we observed an increase in functional responses and phosphorylations in Syk S291A platelets. This potentiation did not occur with AYPGKF or 2-MeSADP, although they also activate PKC isoforms. Although there was potentiation of platelet functional responses, there was no difference in tail bleeding times. However, the time to occlusion in the FeCl injury model was enhanced. These data indicate that the effects of Syk S291 phosphorylation represent a significant outcome on platelet activation and signaling but also reveals its multifaceted nature demonstrated by the differential effects on physiological responses .
Topics: Animals; Syk Kinase; Blood Platelets; Mice; Signal Transduction; Phosphorylation; Immunoreceptor Tyrosine-Based Activation Motif; Gene Knock-In Techniques; Humans; Platelet Membrane Glycoproteins; Platelet Activation
PubMed: 38904212
DOI: 10.1080/09537104.2024.2369766 -
International Journal of Biological... 2024Cysteine-rich angiogenic inducer 61 (CYR61), also called CCN1, has long been characterized as a secretory protein. Nevertheless, the intracellular function of CYR61...
Cysteine-rich angiogenic inducer 61 (CYR61), also called CCN1, has long been characterized as a secretory protein. Nevertheless, the intracellular function of CYR61 remains unclear. Here, we found that CYR61 is important for proper cell cycle progression. Specifically, CYR61 interacts with microtubules and promotes microtubule polymerization to ensure mitotic entry. Moreover, CYR61 interacts with PLK1 and accumulates during the mitotic process, followed by degradation as mitosis concludes. The proteolysis of CYR61 requires the PLK1 kinase activity, which directly phosphorylates two conserved motifs on CYR61, enhancing its interaction with the SCF E3 complex subunit FBW7 and mediating its degradation by the proteasome. Mutations of phosphorylation sites of Ser167 and Ser188 greatly increase CYR61's stability, while deletion of CYR61 extends prophase and metaphase and delays anaphase onset. In summary, our findings highlight the precise control of the intracellular CYR61 by the PLK1-FBW7 pathway, accentuating its significance as a microtubule-associated protein during mitotic progression.
Topics: Protein Serine-Threonine Kinases; Humans; Polo-Like Kinase 1; Mitosis; Cell Cycle Proteins; Proto-Oncogene Proteins; Cysteine-Rich Protein 61; Microtubules; F-Box-WD Repeat-Containing Protein 7; HeLa Cells; Phosphorylation; Ubiquitin-Protein Ligases; Microtubule-Associated Proteins
PubMed: 38904029
DOI: 10.7150/ijbs.93335 -
International Journal of Biological... 2024Aberrant activation of the PI3K/Akt pathway commonly occurs in cancers and correlates with multiple aspects of malignant progression. In particular, recent evidence... (Review)
Review
Aberrant activation of the PI3K/Akt pathway commonly occurs in cancers and correlates with multiple aspects of malignant progression. In particular, recent evidence suggests that the PI3K/Akt signaling plays a fundamental role in promoting the so-called aerobic glycolysis or Warburg effect, by phosphorylating different nutrient transporters and metabolic enzymes, such as GLUT1, HK2, PFKB3/4 and PKM2, and by regulating various molecular networks and proteins, including mTORC1, GSK3, FOXO transcription factors, MYC and HIF-1α. This leads to a profound reprogramming of cancer metabolism, also impacting on pentose phosphate pathway, mitochondrial oxidative phosphorylation, de novo lipid synthesis and redox homeostasis and thereby allowing the fulfillment of both the catabolic and anabolic demands of tumor cells. The present review discusses the interactions between the PI3K/Akt cascade and its metabolic targets, focusing on their possible therapeutic implications.
Topics: Humans; Neoplasms; Proto-Oncogene Proteins c-akt; Glucose; Signal Transduction; Phosphatidylinositol 3-Kinases; Animals; Glycolysis
PubMed: 38904014
DOI: 10.7150/ijbs.89942 -
International Journal of Biological... 2024Atopic dermatitis (AD) is a common inflammation skin disease that involves dysregulated interplay between immune cells and keratinocytes. Interleukin-38 (IL-38), a...
Atopic dermatitis (AD) is a common inflammation skin disease that involves dysregulated interplay between immune cells and keratinocytes. Interleukin-38 (IL-38), a poorly characterized IL-1 family cytokine, its role and mechanism in the pathogenesis of AD is elusive. Here, we show that IL-38 is mainly secreted by epidermal keratinocytes and highly expressed in the skin and downregulated in AD lesions. We generated IL-38 keratinocyte-specific knockout mice ( ) and induced AD models by 2,4-dinitrofluorobenzene (DNFB). Unexpectedly, after treatment with DNFB, mice were less susceptible to cutaneous inflammation of AD. Moreover, keratinocyte-specific deletion of IL-38 suppressed the migration of Langerhans cells (LCs) into lymph nodes which results in disturbed differentiation of CD4T cells and decreased the infiltration of immune cells into AD lesions. LCs are a type of dendritic cell that reside specifically in the epidermis and regulate immune responses. We developed LC-like cells from mouse bone marrow (BM) and treated with recombined IL-38. The results show that IL-38 depended on IL-36R, activated the phosphorylated expression of IRAK4 and NF-κB P65 and upregulated the expression of CCR7 to promoting the migration of LCs, nevertheless, the upregulation disappeared with the addition of IL-36 receptor antagonist (IL-36RA), IRAK4 or NF-κB P65 inhibitor. Furthermore, after treatment with IRAK4 inhibitors, the experimental AD phenotypes were alleviated and so IRAK4 is considered a promising target for the treatment of inflammatory diseases. Overall, our findings indicated a potential pathway that IL-38 depends on IL-36R, leading to LCs migration to promote AD by upregulating CCR7 via IRAK4/NF-κB and implied the prevention and treatment of AD, supporting potential clinical utilization of IRAK4 inhibitors in AD treatment.
Topics: Animals; Dermatitis, Atopic; Langerhans Cells; Mice; Cell Movement; Mice, Knockout; Interleukin-1; Keratinocytes; Dinitrofluorobenzene; NF-kappa B; Interleukins
PubMed: 38904012
DOI: 10.7150/ijbs.93843 -
Frontiers in Genetics 2024Several mutations in the gene have been identified as a causative link to VWS. In this investigation, whole-exome sequencing (WES) and Sanger sequencing of a...
Several mutations in the gene have been identified as a causative link to VWS. In this investigation, whole-exome sequencing (WES) and Sanger sequencing of a three-generation pedigree with an autosomal-dominant inheritance pattern affected by VWS identified a unique stop-gain mutation-c.748C>T:p.R250X-in the gene that co-segregated exclusively with the disease phenotype. Immunofluorescence analysis revealed that the -p.R250X mutation predominantly shifted its localization from the nucleus to the cytoplasm. WES and protein interaction analyses were conducted to understand this mutation's role in the pathogenesis of VWS. Using LC-MS/MS, we found that this mutation led to a reduction in the binding of IRF6 to histone modification-associated proteins (NAA10, SNRPN, NAP1L1). Furthermore, RNA-seq results show that the mutation resulted in a downregulation of TGFβ2-AS1 expression. The findings highlight the mutation's influence on and its subsequent effects on the phosphorylation of SMAD2/3, which are critical in maxillofacial development, particularly the palate. These insights contribute to a deeper understanding of VWS's molecular underpinnings and might inform future therapeutic strategies.
PubMed: 38903762
DOI: 10.3389/fgene.2024.1397410 -
Frontiers in Immunology 2024Protein kinases are indispensable reversible molecular switches that adapt and control protein functions during cellular processes requiring rapid responses to internal...
INTRODUCTION
Protein kinases are indispensable reversible molecular switches that adapt and control protein functions during cellular processes requiring rapid responses to internal and external events. Bacterial infections can affect kinase-mediated phosphorylation events, with consequences for both innate and adaptive immunity, through regulation of antigen presentation, pathogen recognition, cell invasiveness and phagocytosis. (), a human respiratory tract pathogen and a major cause of community-acquired pneumoniae, affects phosphorylation-based signalling of several kinases, but the pneumococcal mediator(s) involved in this process remain elusive. In this study, we investigated the influence of pneumococcal HO on the protein kinase activity of the human lung epithelial H441 cell line, a generally accepted model of alveolar epithelial cells.
METHODS
We performed kinome analysis using PamGene microarray chips and protein analysis in Western blotting in H441 lung cells infected with wild type () or with -a deletion mutant strongly attenuated in HO production- to assess the impact of pneumococcal hydrogen peroxide (HO) on global protein kinase activity profiles.
RESULTS
Our kinome analysis provides direct evidence that kinase activity profiles in infected H441 cells significantly vary according to the levels of pneumococcal HO. A large number of kinases in H441 cells infected with are significantly downregulated, whereas this no longer occurs in cells infected with the mutant strain, which lacks HO In particular, we describe for the first time HO-mediated downregulation of Protein kinase B (Akt1) and activation of lymphocyte-specific tyrosine protein kinase (Lck) via HO-mediated phosphorylation.
Topics: Streptococcus pneumoniae; Hydrogen Peroxide; Humans; Phosphorylation; Host-Pathogen Interactions; Cell Line; Protein Kinases; Pneumococcal Infections; Signal Transduction
PubMed: 38903521
DOI: 10.3389/fimmu.2024.1414195 -
BioRxiv : the Preprint Server For... Jun 2024Evolutionary arms races can arise at the contact surfaces between host and viral proteins, producing dynamic spaces in which genetic variants are continually pursued....
Evolutionary arms races can arise at the contact surfaces between host and viral proteins, producing dynamic spaces in which genetic variants are continually pursued. However, the sampling of genetic variation must be balanced with the need to maintain protein function. A striking case is given by protein kinase R (PKR), a member of the mammalian innate immune system. PKR detects viral replication within the host cell and halts protein synthesis to prevent viral replication by phosphorylating eIF2α, a component of the translation initiation machinery. PKR is targeted by many viral antagonists, including poxvirus pseudosubstrate antagonists that inhibit PKR by interacting with the same binding surface as eIF2α. Remarkably, PKR has several rapidly evolving residues at this interface, suggesting it is engaging in an evolutionary arms race, despite the surface's critical role in phosphorylating eIF2α. To systematically explore the evolutionary opportunities available at this dynamic interface, we generated and characterized a library of 426 SNP-accessible nonsynonymous variants of human PKR for their ability to escape inhibition by the model pseudosubstrate inhibitor K3 from vaccinia virus. We identified key sites in the PKR kinase domain that harbor K3-resistant variants, as well as critical sites where variation leads to loss of function. We find K3-resistant variants are readily available throughout the interface and are enriched at sites under positive selection. Moreover, variants beneficial against K3 were also beneficial against an enhanced variant of K3, indicating resilience to viral adaptation. Overall, we find that the eIF2α-binding surface of PKR is highly malleable, potentiating its evolutionary ability to combat viral inhibition.
PubMed: 38903081
DOI: 10.1101/2024.05.29.596416 -
BioRxiv : the Preprint Server For... Apr 2024Dynein cytoplasmic 1 light intermediate chain 1 (LIC1, ) is a core subunit of the dynein motor complex. The LIC1 subunit also interacts with various cargo adaptors to...
Dynein cytoplasmic 1 light intermediate chain 1 (LIC1, ) is a core subunit of the dynein motor complex. The LIC1 subunit also interacts with various cargo adaptors to regulate Rab-mediated endosomal recycling and lysosomal degradation. Defects in this gene are predicted to alter dynein motor function, Rab binding capabilities, and cytoplasmic cargo trafficking. Here, we have identified a zebrafish mutant, harboring a premature stop codon at the exon 12/13 splice acceptor site, that displays increased angiogenesis. , LIC1-deficient human endothelial cells display increases in cell surface levels of the pro-angiogenic receptor VEGFR2, SRC phosphorylation, and Rab11-mediated endosomal recycling. , endothelial-specific expression of constitutively active leads to excessive angiogenesis, similar to the mutants. Increased angiogenesis is also evident in zebrafish harboring mutations in , the adaptor proteins that promote Rab docking to Lic1 to mediate lysosomal targeting. These findings suggest that LIC1 and the Rab-adaptor proteins RILPL1 and 2 restrict angiogenesis by promoting degradation of VEGFR2-containing recycling endosomes. Disruption of LIC1- and RILPL1/2-mediated lysosomal targeting increases Rab11-mediated recycling endosome activity, promoting excessive SRC signaling and angiogenesis.
PubMed: 38903077
DOI: 10.1101/2024.04.01.587559