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The role of PALLD-STAT3 interaction in megakaryocyte differentiation and thrombocytopenia treatment.Haematologica May 2024Impaired differentiation of megakaryocytes constitutes the principal etiology of thrombocytopenia. The signal transducer and activator of transcription 3 (STAT3) is a...
Impaired differentiation of megakaryocytes constitutes the principal etiology of thrombocytopenia. The signal transducer and activator of transcription 3 (STAT3) is a crucial transcription factor in regulating megakaryocyte differentiation, yet the precise mechanism of its activation remains unclear. PALLD, an actin-associated protein, has been increasingly recognized for its essential functions in multiple biological processes. This study revealed that megakaryocyte/plateletspecific knockout of PALLD in mice exhibited thrombocytopenia due to diminished platelet biogenesis. In megakaryocytes, PALLD deficiency led to impaired proplatelet formation and polyploidization, ultimately weakening their differentiation for platelet production. Mechanistic studies demonstrated that PALLD bound to STAT3 and interacted with its DNA-binding domain (DBD) and Src homology 2 (SH2) domain via Immunoglobulin domain 3 (Ig3). Moreover, the absence of PALLD attenuated STAT3 Y705 phosphorylation and impeded STAT3 nuclear translocation. Based on the PALLD-STAT3 binding sequence, we designed a peptide C-P3, which can facilitate megakaryocyte differentiation and accelerate platelet production in vivo. In conclusion, this study highlights the pivotal role of PALLD in megakaryocyte differentiation and proposes a novel approach for treating thrombocytopenia by targeting the PALLD-STAT3 interaction.
PubMed: 38813732
DOI: 10.3324/haematol.2024.285242 -
Journal of Nanobiotechnology May 2024The signal sequence played a crucial role in the efficacy of mRNA vaccines against virus pandemic by influencing antigen translation. However, limited research had been...
The signal sequence played a crucial role in the efficacy of mRNA vaccines against virus pandemic by influencing antigen translation. However, limited research had been conducted to compare and analyze the specific mechanisms involved. In this study, a novel approach was introduced by substituting the signal sequence of the mRNA antigen to enhance its immune response. Computational simulations demonstrated that various signal peptides differed in their binding capacities with the signal recognition particle (SRP) 54 M subunit, which positively correlated with antigen translation efficiency. Our data revealed that the signal sequences of tPA and IL-6-modified receptor binding domain (RBD) mRNA vaccines sequentially led to higher antigen expression and elicited more robust humoral and cellular immune protection against the SARS-CoV-2 compared to the original signal sequence. By highlighting the importance of the signal sequence, this research provided a foundational and safe approach for ongoing modifications in signal sequence-antigen design, aiming to optimize the efficacy of mRNA vaccines.
Topics: Animals; mRNA Vaccines; Mice; SARS-CoV-2; Protein Sorting Signals; COVID-19; Mice, Inbred BALB C; RNA, Messenger; COVID-19 Vaccines; Female; Humans; Antigens, Viral; Antibodies, Viral; Immunity, Humoral; Vaccines, Synthetic; Immunity, Cellular
PubMed: 38807131
DOI: 10.1186/s12951-024-02488-3 -
BioRxiv : the Preprint Server For... May 2024The insulin receptor (IR) and the insulin-like growth factor-1 receptor (IGF1R) are homodimeric transmembrane glycoproteins that transduce signals across the membrane on...
The insulin receptor (IR) and the insulin-like growth factor-1 receptor (IGF1R) are homodimeric transmembrane glycoproteins that transduce signals across the membrane on binding of extracellular peptide ligands. The structures of IR/IGF1R fragments in apo and liganded states have revealed that the extracellular subunits of these receptors adopt Λ-shaped configurations to which are connected the intracellular tyrosine kinase (TK) domains. The binding of peptide ligands induces structural transitions in the extracellular subunits leading to potential dimerization of transmembrane domains (TMDs) and autophosphorylation in TKs. However, the activation mechanisms of IR/IGF1R, especially the role of TMDs in coordinating signal-inducing structural transitions, remain poorly understood, in part due to the lack of structures of full-length receptors in apo or liganded states. While atomistic simulations of IR/IGF1R TMDs showed that these domains can dimerize in single component membranes, spontaneous unbiased dimerization in a plasma membrane having physiologically representative lipid composition has not been observed. We address this limitation by employing coarsegrained (CG) molecular dynamics simulations to probe the dimerization propensity of IR/IGF1R TMDs. We observed that TMDs in both receptors spontaneously dimerized independent of their initial orientations in their dissociated states, signifying their natural propensity for dimerization. In the dimeric state, IR TMDs predominantly adopted X-shaped configurations with asymmetric helical packing and significant tilt relative to the membrane normal, while IGF1R TMDs adopted symmetric V-shaped or parallel configurations with either no tilt or a small tilt relative to the membrane normal. Our results suggest that IR/IGF1R TMDs spontaneously dimerize and adopt distinct dimerized configurations.
PubMed: 38798363
DOI: 10.1101/2024.05.09.593448 -
Nutrients May 2024Unhealthy lifestyles (high-fat diet, smoking, alcohol consumption, too little exercise, etc.) in the current society are prone to cause lipid metabolism disorders... (Review)
Review
Unhealthy lifestyles (high-fat diet, smoking, alcohol consumption, too little exercise, etc.) in the current society are prone to cause lipid metabolism disorders affecting the health of the organism and inducing the occurrence of diseases. Saponins, as biologically active substances present in plants, have lipid-lowering, inflammation-reducing, and anti-atherosclerotic effects. Saponins are thought to be involved in the regulation of lipid metabolism in the body; it suppresses the appetite and, thus, reduces energy intake by modulating pro-opiomelanocortin/Cocaine amphetamine regulated transcript (POMC/CART) neurons and neuropeptide Y/agouti-related peptide (NPY/AGRP) neurons in the hypothalamus, the appetite control center. Saponins directly activate the AMP-activated protein kinase (AMPK) signaling pathway and related transcriptional regulators such as peroxisome-proliferator-activated-receptors (PPAR), CCAAT/enhancer-binding proteins (C/EBP), and sterol-regulatory element binding proteins (SREBP) increase fatty acid oxidation and inhibit lipid synthesis. It also modulates gut-liver interactions to improve lipid metabolism by regulating gut microbes and their metabolites and derivatives-short-chain fatty acids (SCFAs), bile acids (BAs), trimethylamine (TMA), lipopolysaccharide (LPS), et al. This paper reviews the positive effects of different saponins on lipid metabolism disorders, suggesting that the gut-liver axis plays a crucial role in improving lipid metabolism processes and may be used as a therapeutic target to provide new strategies for treating lipid metabolism disorders.
Topics: Saponins; Lipid Metabolism; Humans; Liver; Gastrointestinal Microbiome; Animals; Signal Transduction; Gastrointestinal Tract
PubMed: 38794751
DOI: 10.3390/nu16101514 -
Viruses May 2024The L 1 region of bovine adenovirus (BAdV)-3 encodes a multifunctional protein named protein VII. Anti-protein VII sera detected a protein of 26 kDa in transfected or...
The L 1 region of bovine adenovirus (BAdV)-3 encodes a multifunctional protein named protein VII. Anti-protein VII sera detected a protein of 26 kDa in transfected or BAdV-3-infected cells, which localizes to nucleus and nucleolus of infected/transfected cells. Analysis of mutant protein VII identified four redundant overlapping nuclear/nucleolar localization signals as deletion of all four potential nuclear/nucleolar localization signals localizes protein VII predominantly to the cytoplasm. The nuclear import of protein VII appears to use importin α (α-1), importin-β (β-1) and transportin-3 nuclear transport receptors. In addition, different nuclear transport receptors also require part of protein VII outside nuclear localization sequences for efficient interaction. Proteomic analysis of protein complexes purified from recombinant BAdV-3 expressing protein VII containing Strep Tag II identified potential viral and cellular proteins interacting with protein VII. Here, we confirm that protein VII interacts with IVa2 and protein VIII in BAdV-3-infected cells. Moreover, amino acids 91-101 and 126-137, parts of non-conserved region of protein VII, are required for interaction with IVa2 and protein VIII, respectively.
Topics: Animals; Cattle; Mastadenovirus; Viral Proteins; Protein Binding; Cell Line; Cell Nucleus; Proteomics; Host-Pathogen Interactions; Nuclear Localization Signals; Active Transport, Cell Nucleus; Humans
PubMed: 38793614
DOI: 10.3390/v16050732 -
International Journal of Molecular... May 2024Alzheimer's disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the... (Review)
Review
Alzheimer's disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the disease pathophysiology and to find potential therapeutic interventions. In this regard, G protein-coupled receptors (GPCRs) have emerged as novel potential therapeutic targets to palliate the progression of neurodegenerative diseases such as AD. Orexin and cannabinoid receptors are GPCRs capable of forming heteromeric complexes with a relevant role in the development of this disease. On the one hand, the hyperactivation of the orexins system has been associated with sleep-wake cycle disruption and Aβ peptide accumulation. On the other hand, cannabinoid receptor overexpression takes place in a neuroinflammatory environment, favoring neuroprotective effects. Considering the high number of interactions between cannabinoid and orexin systems that have been described, regulation of this interplay emerges as a new focus of research. In fact, in microglial primary cultures of APPSw/Ind mice model of AD there is an important increase in CBR-OXR complex expression, while OXR antagonism potentiates the neuroprotective effects of CBR. Specifically, pretreatment with the OXR antagonist has been shown to strongly potentiate CBR signaling in the cAMP pathway. Furthermore, the blockade of OXR can also abolish the detrimental effects of OXR overactivation in AD. In this sense, CBR-OXR becomes a new potential therapeutic target to combat AD.
Topics: Alzheimer Disease; Animals; Humans; Cannabinoids; Orexins; Orexin Receptors; Receptors, Cannabinoid; Signal Transduction; Amyloid beta-Peptides
PubMed: 38791416
DOI: 10.3390/ijms25105378 -
International Journal of Molecular... May 2024Protein farnesylation is a post-translational modification where a 15-carbon farnesyl isoprenoid is appended to the C-terminal end of a protein by farnesyltransferase...
Protein farnesylation is a post-translational modification where a 15-carbon farnesyl isoprenoid is appended to the C-terminal end of a protein by farnesyltransferase (FTase). This process often causes proteins to associate with the membrane and participate in signal transduction pathways. The most common substrates of FTase are proteins that have C-terminal tetrapeptide CaaX box sequences where the cysteine is the site of modification. However, recent work has shown that five amino acid sequences can also be recognized, including the pentapeptides CMIIM and CSLMQ. In this work, peptide libraries were initially used to systematically vary the residues in those two parental sequences using an assay based on Matrix Assisted Laser Desorption Ionization-Mass Spectrometry (MALDI-MS). In addition, 192 pentapeptide sequences from the human proteome were screened using that assay to discover additional extended CaaaX-box motifs. Selected hits from that screening effort were rescreened using an in vivo yeast reporter protein assay. The X-ray crystal structure of CMIIM bound to FTase was also solved, showing that the C-terminal tripeptide of that sequence interacted with the enzyme in a similar manner as the C-terminal tripeptide of CVVM, suggesting that the tripeptide comprises a common structural element for substrate recognition in both tetrapeptide and pentapeptide sequences. Molecular dynamics simulation of CMIIM bound to FTase further shed light on the molecular interactions involved, showing that a putative catalytically competent Zn(II)-thiolate species was able to form. Bioinformatic predictions of tetrapeptide (CaaX-box) reactivity correlated well with the reactivity of pentapeptides obtained from in vivo analysis, reinforcing the importance of the C-terminal tripeptide motif. This analysis provides a structural framework for understanding the reactivity of extended CaaaX-box motifs and a method that may be useful for predicting the reactivity of additional FTase substrates bearing CaaaX-box sequences.
Topics: Humans; Computational Biology; Peptide Library; Substrate Specificity; Farnesyltranstransferase; Oligopeptides; Amino Acid Sequence; Crystallography, X-Ray; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Protein Binding
PubMed: 38791363
DOI: 10.3390/ijms25105324 -
International Journal of Molecular... May 2024Leptin is an obesity-related hormone that plays an important role in breast cancer progression. Vasculogenic mimicry (VM) refers to the formation of vascular channels...
Leptin is an obesity-related hormone that plays an important role in breast cancer progression. Vasculogenic mimicry (VM) refers to the formation of vascular channels lined by tumor cells. This study aimed to investigate the relationship between leptin and VM in human breast cancer cells. VM was measured by a 3D culture assay. Signal transducers and activators of transcription 3 (STAT3) signaling, aquaporin-1 (AQP1), and the expression of VM-related proteins, including vascular endothelial cadherin (VE-cadherin), twist, matrix metalloproteinase-2 (MMP-2), and laminin subunit 5 gamma-2 (LAMC2), were examined by Western blot. AQP1 mRNA was analyzed by a reverse transcriptase-polymerase chain reaction (RT-PCR). Leptin increased VM and upregulated phospho-STAT3, VE-cadherin, twist, MMP-2, and LAMC2. These effects were inhibited by the leptin receptor-blocking peptide, Ob-R BP, and the STAT3 inhibitor, AG490. A positive correlation between leptin and AQP1 mRNA was observed and was confirmed by RT-PCR. Leptin upregulated AQP1 expression, which was blocked by Ob-R BP and AG490. AQP1 overexpression increased VM and the expression of VM-related proteins. AQP1 silencing inhibited leptin-induced VM and the expression of VM-related proteins. Thus, these results showed that leptin facilitates VM in breast cancer cells via the Ob-R/STAT3 pathway and that AQP1 is a key mediator in leptin-induced VM.
Topics: Humans; Leptin; Breast Neoplasms; Aquaporin 1; Female; STAT3 Transcription Factor; Neovascularization, Pathologic; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Signal Transduction; Matrix Metalloproteinase 2; Cadherins; MCF-7 Cells; Laminin; Antigens, CD
PubMed: 38791252
DOI: 10.3390/ijms25105215 -
Genes May 2024Barley ( L.), a diverse cereal crop, exhibits remarkable versatility in its applications, ranging from food and fodder to industrial uses. The content of cellulose in...
Barley ( L.), a diverse cereal crop, exhibits remarkable versatility in its applications, ranging from food and fodder to industrial uses. The content of cellulose in barley is significantly influenced by the genes, which encode the plant glycosylphosphatidylinositol (GPI)-anchored protein (GAP) that plays a pivotal role in the deposition of cellulose within the cell wall. The COBL (COBRA-Like) gene family has been discovered across numerous species, yet the specific members of this family in barley remain undetermined. In this study, we discovered 13 COBL genes within the barley genome using bioinformatics methods, subcellular localization, and protein structure analysis, finding that most of the barley COBL proteins have a signal peptide structure and are localized on the plasma membrane. Simultaneously, we constructed a phylogenetic tree and undertook a comprehensive analysis of the evolutionary relationships. Other characteristics of family members, including intraspecific collinearity, gene structure, conserved motifs, and cis-acting elements, were thoroughly characterized in detail. The assessment of gene expression in barley under various hormone treatments was conducted through qRT-PCR analysis, revealing jasmonic acid (JA) as the predominant hormonal regulator of gene expression. In summary, this study comprehensively identified and analyzed the barley gene family, aiming to provide basic information for exploring the members of the gene family and to propose directions for further research.
Topics: Hordeum; Plant Proteins; Multigene Family; Gene Expression Regulation, Plant; Phylogeny; Plant Growth Regulators; Genome, Plant; Oxylipins; Cyclopentanes
PubMed: 38790240
DOI: 10.3390/genes15050612 -
Marine Drugs May 2024Alginate oligosaccharides (AOS), products of alginate degradation by endotype alginate lyases, possess favorable biological activities and have broad applications....
Alginate oligosaccharides (AOS), products of alginate degradation by endotype alginate lyases, possess favorable biological activities and have broad applications. Although many have been reported, alginate lyases with homogeneous AOS products and secretory production by an engineered host are scarce. Herein, the alginate lyase AlyC7 from sp. C42 was characterized as a trisaccharide-producing lyase exhibiting high activity and broad substrate specificity. With PelB as the signal peptide and 500 mM glycine as the additive, the extracellular production of AlyC7 in reached 1122.8 U/mL after 27 h cultivation in Luria-Bertani medium. The yield of trisaccharides from sodium alginate degradation by the produced AlyC7 reached 758.6 mg/g, with a purity of 85.1%. The prepared AOS at 20 μg/mL increased the root length of lettuce, tomato, wheat, and maize by 27.5%, 25.7%, 9.7%, and 11.1%, respectively. This study establishes a robust foundation for the industrial and agricultural applications of AlyC7.
Topics: Polysaccharide-Lyases; Trisaccharides; Escherichia coli; Vibrio; Substrate Specificity; Alginates; Zea mays; Oligosaccharides
PubMed: 38786621
DOI: 10.3390/md22050230