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Brain Communications 2024Huntington's disease is a neurodegenerative disorder in which neuronal death leads to chorea and cognitive decline. Individuals with ≥40 cytosine-adenine-guanine...
Huntington's disease is a neurodegenerative disorder in which neuronal death leads to chorea and cognitive decline. Individuals with ≥40 cytosine-adenine-guanine repeats on the interesting transcript 15 gene develop Huntington's disease due to a mutated huntingtin protein. While the associated structural and molecular changes are well characterized, the alterations in neurovascular function that lead to the symptoms are not yet fully understood. Recently, the neurovascular unit has gained attention as a key player in neurodegenerative diseases. The mutant huntingtin protein is known to be present in the major parts of the neurovascular unit in individuals with Huntington's disease. However, a non-invasive assessment of neurovascular unit function in Huntington's disease has not yet been performed. Here, we investigate neurovascular interactions in presymptomatic ( = 13) and symptomatic ( = 15) Huntington's disease participants compared to healthy controls ( = 36). To assess the dynamics of oxygen transport to the brain, functional near-infrared spectroscopy, ECG and respiration effort were recorded. Simultaneously, neuronal activity was assessed using EEG. The resultant time series were analysed using methods for discerning time-resolved multiscale dynamics, such as wavelet transform power and wavelet phase coherence. Neurovascular phase coherence in the interval around 0.1 Hz is significantly reduced in both Huntington's disease groups. The presymptomatic Huntington's disease group has a lower power of oxygenation oscillations compared to controls. The spatial coherence of the oxygenation oscillations is lower in the symptomatic Huntington's disease group compared to the controls. The EEG phase coherence, especially in the α band, is reduced in both Huntington's disease groups and, to a significantly greater extent, in the symptomatic group. Our results show a reduced efficiency of the neurovascular unit in Huntington's disease both in the presymptomatic and symptomatic stages of the disease. The vasculature is already significantly impaired in the presymptomatic stage of the disease, resulting in reduced cerebral blood flow control. The results indicate vascular remodelling, which is most likely a compensatory mechanism. In contrast, the declines in α and γ coherence indicate a gradual deterioration of neuronal activity. The results raise the question of whether functional changes in the vasculature precede the functional changes in neuronal activity, which requires further investigation. The observation of altered dynamics paves the way for a simple method to monitor the progression of Huntington's disease non-invasively and evaluate the efficacy of treatments.
PubMed: 38938620
DOI: 10.1093/braincomms/fcae166 -
Cell Surface (Amsterdam, Netherlands) Jun 2024Host recognition of the pathogen-associated molecular pattern (PAMP), β-1,3-glucan, plays a major role in antifungal immunity. β-1,3-glucan is an essential component...
Host recognition of the pathogen-associated molecular pattern (PAMP), β-1,3-glucan, plays a major role in antifungal immunity. β-1,3-glucan is an essential component of the inner cell wall of the opportunistic pathogen . Most β-1,3-glucan is shielded by the outer cell wall layer of mannan fibrils, but some can become exposed at the cell surface. In response to host signals such as lactate, shaves the exposed β-1,3-glucan from its cell surface, thereby reducing the ability of innate immune cells to recognise and kill the fungus. We have used sets of barcoded and mutants to compare the impacts of the secreted β-glucanases Xog1 and Eng1 upon and . Flow cytometry of Fc-dectin-1-stained strains revealed that Eng1 plays the greater role in lactate-induced β-1,3-glucan masking. Transmission electron microscopy and stress assays showed that neither Eng1 nor Xog1 are essential for cell wall maintenance, but the inactivation of either enzyme compromised fungal adhesion to gut and vaginal epithelial cells. Competitive barcode sequencing suggested that neither Eng1 nor Xog1 strongly influence fitness during systemic infection or vaginal colonisation in mice. However, the deletion of enhanced fitness during gut colonisation. We conclude that both Eng1 and Xog1 exert subtle effects on the cell surface that influence fungal adhesion to host cells and that affect fungal colonisation in certain host niches.
PubMed: 38938582
DOI: 10.1016/j.tcsw.2024.100128 -
Frontiers in Immunology 2024TRIM21 is a pivotal effector in the immune system, orchestrating antibody-mediated responses and modulating immune signaling. In this comprehensive study, we focus on...
TRIM21 is a pivotal effector in the immune system, orchestrating antibody-mediated responses and modulating immune signaling. In this comprehensive study, we focus on the interaction of TRIM21 with Fc engineered antibodies and subsequent implications for viral neutralization. Through a series of analytical techniques, including biosensor assays, mass photometry, and electron microscopy, along with structure predictions, we unravel the intricate mechanisms governing the interplay between TRIM21 and antibodies. Our investigations reveal that the TRIM21 capacity to recognize, bind, and facilitate the proteasomal degradation of antibody-coated viruses is critically dependent on the affinity and avidity interplay of its interactions with antibody Fc regions. We suggest a novel binding mechanism, where TRIM21 binding to one Fc site results in the detachment of PRYSPRY from the coiled-coil domain, enhancing mobility due to its flexible linker, thereby facilitating the engagement of the second site, resulting in avidity due to bivalent engagement. These findings shed light on the dual role of TRIM21 in antiviral immunity, both in recognizing and directing viruses for intracellular degradation, and demonstrate its potential for therapeutic exploitation. The study advances our understanding of intracellular immune responses and opens new avenues for the development of antiviral strategies and innovation in tailored effector functions designed to leverage TRIM21s unique binding mode.
Topics: Humans; Ribonucleoproteins; Protein Binding; Antibodies, Neutralizing; Immunoglobulin Fc Fragments; Protein Engineering; Antibodies, Viral; Antibody Affinity; Animals
PubMed: 38938560
DOI: 10.3389/fimmu.2024.1401471 -
MicroPublication Biology 2024The GTPase, Spg1 , activates the septation initiation network (SIN) protein kinase cascade to trigger septation. In the absence of functional Spg1 , cells fail...
The GTPase, Spg1 , activates the septation initiation network (SIN) protein kinase cascade to trigger septation. In the absence of functional Spg1 , cells fail cytokinesis and become multinucleate. In this study, we characterize a set of temperature-sensitive alleles isolated in the 1990s. We identify the mutations within each new and previously characterized allele, characterize the extent of relative growth defects, and assess their interaction with other SIN alleles.
PubMed: 38938413
DOI: 10.17912/micropub.biology.001193 -
Biology Methods & Protocols 2024Real-time polymerase chain reaction (real-time PCR) is a powerful tool for the precise quantification of nucleic acids in various applications. In cancer management, the...
Real-time polymerase chain reaction (real-time PCR) is a powerful tool for the precise quantification of nucleic acids in various applications. In cancer management, the monitoring of circulating tumor DNA (ctDNA) from liquid biopsies can provide valuable information for precision care, including treatment selection and monitoring, prognosis, and early detection. However, the rare and heterogeneous nature of ctDNA has made its precise detection and quantification challenging, particularly for ctDNA containing hotspot mutations. We have developed a new real-time PCR tool, PROMER technology, which enables the precise and sensitive detection of ctDNA containing cancer-driven single-point mutations. The PROMER functions as both a PRObe and priMER, providing enhanced detection specificity. We validated PROMER technology using synthetic templates with known KRAS point mutations and demonstrated its sensitivity and linearity of quantification. Using genomic DNA from human cancer cells with mutant and wild-type KRAS, we confirmed that PROMER PCR can detect mutant DNA. Furthermore, we demonstrated the ability of PROMER technology to efficiently detect mutation-carrying ctDNA from the plasma of mice with human cancers. Our results suggest that PROMER technology represents a promising new tool for the precise detection and quantification of DNA containing point mutations in the presence of a large excess of wild-type counterpart.
PubMed: 38938409
DOI: 10.1093/biomethods/bpae041 -
Genes To Cells : Devoted To Molecular &... Jun 2024Global proliferative arrest (GPA) is a phenomenon in monocarpic plants in which the activity of all aboveground meristems generally ceases in a nearly coordinated manner...
Global proliferative arrest (GPA) is a phenomenon in monocarpic plants in which the activity of all aboveground meristems generally ceases in a nearly coordinated manner after the formation of a certain number of fruits. Despite the fact that GPA is a biologically and agriculturally important event, the underlying molecular mechanisms are not well understood. In this study, we attempted to elucidate the molecular mechanism of GPA regulation by identifying the gene responsible for the Arabidopsis mutant fireworks (fiw), causing an early GPA phenotype. Map-based cloning revealed that the fiw gene encodes CYSTEIN-RICH RECEPTOR-LIKE KINASE 14 (CRK14). Genetic analysis suggested that fiw is a missense, gain-of-function allele of CRK14. Since overexpression of the extracellular domain of CRK14 resulted in delayed GPA in the wild-type background, we concluded that CRK14 is involved in GPA regulation. Analysis of double mutants revealed that fiw acts downstream of or independently of the FRUITFULL-APETALA2 (AP2)/AP2-like pathway, which was previously reported as an age-dependent default pathway in GPA regulation. In addition, fiw is epistatic to clv with respect to GPA control. Furthermore, we found a negative effect on WUSCHEL expression in the fiw mutants. These results thus suggest the existence of a novel CRK14-dependent signaling pathway involved in GPA regulation.
PubMed: 38938200
DOI: 10.1111/gtc.13139 -
ACS Infectious Diseases Jun 2024A newly discovered E3 ubiquitin ligase, UBR7, plays a crucial role in histone H2BK120 monoubiquitination. Here, we report a novel function of UBR7 in promoting hepatitis...
A newly discovered E3 ubiquitin ligase, UBR7, plays a crucial role in histone H2BK120 monoubiquitination. Here, we report a novel function of UBR7 in promoting hepatitis B virus (HBV) pathogenesis, which further leads to HBV-induced hepatocellular carcinoma (HCC). Transcriptomics analysis from HCC patients revealed the deregulation of UBR7 in cancer. Remarkably, targeting UBR7, particularly its catalytic function, led to a significant decrease in viral copy numbers. We also identified the speckled family protein Sp110 as an important substrate of UBR7. Notably, Sp110 has been previously shown to be a resident of promyelocytic leukemia nuclear bodies (PML-NBs), where it remains SUMOylated, and during HBV infection, it undergoes deSUMOylation and exits the PML body. We observed that UBR7 ubiquitinates Sp110 at critical residues within its SAND domain. Sp110 ubiquitination downregulates genes in the type I interferon response pathway. Comparative analysis of RNA-Seq from the UBR7/Sp110 knockdown data set confirmed that the IFN-β signaling pathway gets deregulated in HCC cells in the presence of HBV. Single-cell RNA-Seq analysis of patient samples further confirmed the inverse correlation between the expression of Sp110/UBR7 and the inflammation score. Notably, silencing of UBR7 induces IRF7 phosphorylation, thereby augmenting interferon (IFN)-β and the downstream interferon-stimulated genes (ISGs). Further, wild-type but not the ubiquitination-defective mutant of Sp110 could be recruited to the type I interferon response pathway genes. Our study establishes a new function of UBR7 in non-histone protein ubiquitination, promoting viral persistence, and has important implications for the development of therapeutic strategies targeting HBV-induced HCC.
PubMed: 38938101
DOI: 10.1021/acsinfecdis.4c00213 -
Journal of Experimental Botany Jun 2024Raffinose mitigates plant heat-, drought- and cold- stresses; however, whether raffinose contributes to plant waterlogging tolerance is unknown. The maize zmrafs-1...
Raffinose mitigates plant heat-, drought- and cold- stresses; however, whether raffinose contributes to plant waterlogging tolerance is unknown. The maize zmrafs-1 mutant seedlings lacking raffinose, generate fewer and shorter adventitious root (AR) and are more sensitive to waterlogging stress, while overexpression of ZmRAFS increases raffinose content, stimulates AR formation, and enhances the waterlogging tolerance of maize seedlings. Transcriptome analysis of NS (Null segregant) seedlings compared with that of zmrafs-1, particularly when waterlogged, revealed that the expression of genes related to galactose metabolism and the auxin biosynthetic pathway were upregulated by raffinose. Additionally, Indole-3-acetic acid (IAA) amounts significantly decreased or increased in zmrafs-1 or ZmRAFS-overexpressing seedlings, respectively. Inhibition of the hydrolysis of raffinose by DGJ (1-deoxygalactonojirimycin) decreased the waterlogging tolerance of maize seedlings, decreased the expression of genes encoding proteins related to auxin transport-related genes as well as the IAA level in the seedlings, suggesting that the hydrolysis of raffinose is necessary for maize waterlogging tolerance. These data demonstrate that raffinose catabolism stimulates adventitious root formation via auxin signaling pathway to enhance maize waterlogging tolerance.
PubMed: 38938017
DOI: 10.1093/jxb/erae284 -
Genes To Cells : Devoted To Molecular &... Jun 2024Bacteria use several means to survive under stress conditions such as nutrient depletion. One such response is the formation of hibernating 100S ribosomes, which are...
Bacteria use several means to survive under stress conditions such as nutrient depletion. One such response is the formation of hibernating 100S ribosomes, which are translationally inactive 70S dimers. In Gammaproteobacteria (Enterobacterales), 100S ribosome formation requires ribosome modulation factor (RMF) and short hibernation promoting factor (HPF), whereas it is mediated by only long HPF in the majority of bacteria. Here, we investigated the role of HPFs of Comamonas testosteroni, which belongs to the Betaproteobacteria with common ancestor to the Gammaproteobacteria. C. testosteroni has two genes of HPF homologs of differing length (CtHPF-125 and CtHPF-119). CtHPF-125 was induced in the stationary phase, whereas CtHPF-119 conserved in many other Betaproteobacteria was not expressed in the culture conditions used here. Unlike short HPF and RMF, and long HPF, CtHPF-125 could not form 100S ribosome. We first constructed the deletion mutant of Cthpf-125 gene. When the deletion mutant grows in the stationary phase, 70S particles were degraded faster than in the wild strain. CtHPF-125 contributes to stabilizing the 70S ribosome. CtHPF-125 and CtHPF-119 both inhibited protein synthesis by transcription-translation in vitro. Our findings suggest that CtHPF-125 binds to ribosome, and stabilizes 70S ribosomes, inhibits translation without forming 100S ribosomes and supports prolonging life.
PubMed: 38937957
DOI: 10.1111/gtc.13137 -
Virulence Dec 2024causes globally prevalent infections that are highly related to chronic gastritis and even development of gastric carcinomas. With the increase of antibiotic...
causes globally prevalent infections that are highly related to chronic gastritis and even development of gastric carcinomas. With the increase of antibiotic resistance, scientists have begun to search for better vaccine design strategies to eradicate colonization. However, while current strategies prefer to formulate vaccines with a single antigen, their potential has not yet been fully realized. Outer membrane vesicles (OMVs) are a potential platform since they could deliver multiple antigens. In this study, we engineered three crucial antigen proteins (UreB, CagA, and VacA) onto the surface of OMVs derived from serovar Typhimurium (. Typhimurium) mutant strains using the hemoglobin protease (Hbp) autotransporter system. In various knockout strategies, we found that OMVs isolated from the Δ Δ Δ Δ mutants could cause distinct increases in immunoglobulin G (IgG) and A (IgA) levels and effectively trigger T helper 1- and 17-biased cellular immune responses, which perform a vital role in protecting against . Next, OMVs derived from Δ Δ Δ Δ mutants were used as a vector to deliver different combinations of antigens. The antibody and cytokine levels and challenge experiments in mice model indicated that co-delivering UreB and CagA could protect against and antigen-specific T cell responses. In summary, OMVs derived from the . Typhimurium Δ Δ Δ Δ mutant strain as the vector while importing UreB and CagA as antigenic proteins using the Hbp autotransporter system would greatly benefit controlling infection.
Topics: Animals; Helicobacter Infections; Bacterial Proteins; Helicobacter pylori; Mice; Salmonella typhimurium; Antigens, Bacterial; Bacterial Vaccines; Female; Antibodies, Bacterial; Immunoglobulin G; Genetic Engineering; Urease; Disease Models, Animal
PubMed: 38937901
DOI: 10.1080/21505594.2024.2367783