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International Journal of Molecular... May 2024Alzheimer's disease (AD) is characterized by the deposition in the brain of senile plaques composed of amyloid-β peptides (Aβs) that increase inflammation. An...
Reduction in Hippocampal Amyloid-β Peptide (Aβ) Content during Glycine-Proline-Glutamate (Gly-Pro-Glu) Co-Administration Is Associated with Changes in Inflammation and Insulin-like Growth Factor (IGF)-I Signaling.
Alzheimer's disease (AD) is characterized by the deposition in the brain of senile plaques composed of amyloid-β peptides (Aβs) that increase inflammation. An endogenous peptide derived from the insulin-like growth factor (IGF)-I, glycine-proline-glutamate (GPE), has IGF-I-sensitizing and neuroprotective actions. Here, we examined the effects of GPE on Aβ levels and hippocampal inflammation generated by the intracerebroventricular infusion of Aβ25-35 for 2 weeks (300 pmol/day) in ovariectomized rats and the signaling-related pathways and levels of Aβ-degrading enzymes associated with these GPE-related effects. GPE prevented the Aβ-induced increase in the phosphorylation of p38 mitogen-activated protein kinase and the reduction in activation of signal transducer and activator of transcription 3, insulin receptor substrate-1, and Akt, as well as on interleukin (IL)-2 and IL-13 levels in the hippocampus. The functionality of somatostatin, measured as the percentage of inhibition of adenylate cyclase activity and the levels of insulin-degrading enzyme, was also preserved by GPE co-treatment. These findings indicate that GPE co-administration may protect from Aβ insult by changing hippocampal cytokine content and somatostatin functionality through regulation of leptin- and IGF-I-signaling pathways that could influence the reduction in Aβ levels through modulation of levels and/or activity of Aβ proteases.
Topics: Animals; Amyloid beta-Peptides; Hippocampus; Rats; Insulin-Like Growth Factor I; Signal Transduction; Female; Oligopeptides; Inflammation; Peptide Fragments; Rats, Wistar; Alzheimer Disease; p38 Mitogen-Activated Protein Kinases; Proto-Oncogene Proteins c-akt; Insulin-Like Peptides
PubMed: 38891902
DOI: 10.3390/ijms25115716 -
International Journal of Molecular... May 2024Photoprotective properties of 1,25-dihydroxyvitamin D (1,25(OH)D) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin...
Photoprotective properties of 1,25-dihydroxyvitamin D (1,25(OH)D) to reduce UV-induced DNA damage have been established in several studies. UV-induced DNA damage in skin such as single or double strand breaks is known to initiate several cellular mechanisms including activation of poly(ADP-ribose) (pADPr) polymerase-1 (PARP-1). DNA damage from UV also increases extracellular signal-related kinase (ERK) phosphorylation, which further increases PARP activity. PARP-1 functions by using cellular nicotinamide adenine dinucleotide (NAD+) to synthesise pADPr moieties and attach these to target proteins involved in DNA repair. Excessive PARP-1 activation following cellular stress such as UV irradiation may result in excessive levels of cellular pADPr. This can also have deleterious effects on cellular energy levels due to depletion of NAD+ to suboptimal levels. Since our previous work indicated that 1,25(OH)D reduced UV-induced DNA damage in part through increased repair via increased energy availability, the current study investigated the effect of 1,25(OH)D on UV-induced PARP-1 activity using a novel whole-cell enzyme- linked immunosorbent assay (ELISA) which quantified levels of the enzymatic product of PARP-1, pADPr. This whole cell assay used around 5000 cells per replicate measurement, which represents a 200-400-fold decrease in cell requirement compared to current commercial assays that measure in vitro pADPr levels. Using our assay, we observed that UV exposure significantly increased pADPr levels in human keratinocytes, while 1,25(OH)D significantly reduced levels of UV-induced pADPr in primary human keratinocytes to a similar extent as a known PARP-1 inhibitor, 3-aminobenzamide (3AB). Further, both 1,25(OH)D and 3AB as well as a peptide inhibitor of ERK-phosphorylation significantly reduced DNA damage in UV-exposed keratinocytes. The current findings support the proposal that reduction in pADPr levels may be critical for the function of 1,25(OH)D in skin to reduce UV-induced DNA damage.
Topics: Humans; Ultraviolet Rays; Poly (ADP-Ribose) Polymerase-1; Vitamin D; DNA Damage; Keratinocytes; Calcitriol; DNA Repair; Phosphorylation
PubMed: 38891771
DOI: 10.3390/ijms25115583 -
Plants (Basel, Switzerland) May 2024J. G. Kühn is the causal agent of wheat dwarf bunt (DB), a destructive disease causing tremendous economic losses. Small cysteine-rich secreted proteins (SCPs) of...
J. G. Kühn is the causal agent of wheat dwarf bunt (DB), a destructive disease causing tremendous economic losses. Small cysteine-rich secreted proteins (SCPs) of plant fungi are crucial in modulating host immunity and promoting infection. Little is known about the virulence effectors of . Here, we characterized TcSCP_9014, a novel effector of SCPs, in which suppressed programmed cell death triggered by BAX without relying on its signal peptide (SP). The SP in the N-terminus of TcSCP_9014 was functional in the secretory process. Live-cell imaging in the epidermal cells of suggested that TcSCP_9014 localized to the plasma membrane, cytoplasm, and nucleus. Furthermore, yeast cDNA library screening was performed to obtain the interacting proteins in wheat. Yeast two-hybrid and BiFC assays were applied to validate the interaction of TcSCP_9014 with TaMTAN and TaGAPDH. Our work revealed that the novel effector TcSCP_9014 is vital in modulating plant immunity, which opens up new avenues for plant-pathogen interactions in the infection process.
PubMed: 38891331
DOI: 10.3390/plants13111523 -
Plants (Basel, Switzerland) May 2024Members of the calcium-dependent protein kinase (CDPK/CPK) and SNF-related protein kinase (SnRK) superfamilies are commonly found in plants and some protists. Our...
Members of the calcium-dependent protein kinase (CDPK/CPK) and SNF-related protein kinase (SnRK) superfamilies are commonly found in plants and some protists. Our knowledge of client specificity of the members of this superfamily is fragmentary. As this family is represented by over 30 members in , the identification of kinase-specific and overlapping client relationships is crucial to our understanding the nuances of this large family of kinases as directed towards signal transduction pathways. Herein, we used the kinase client (KiC) assay-a relative, quantitative, high-throughput mass spectrometry-based in vitro phosphorylation assay-to identify and characterize potential CPK/SnRK targets of Arabidopsis. Eight CPKs (1, 3, 6, 8, 17, 24, 28, and 32), four SnRKs (subclass 1 and 2), and PPCK1 and PPCK2 were screened against a synthetic peptide library that contains 2095 peptides and 2661 known phosphorylation sites. A total of 625 in vitro phosphorylation sites corresponding to 203 non-redundant proteins were identified. The most promiscuous kinase, CPK17, had 105 candidate target proteins, many of which had already been discovered. Sequence analysis of the identified phosphopeptides revealed four motifs: LxRxxS, RxxSxxR, RxxS, and LxxxxS, that were significantly enriched among CPK/SnRK clients. The results provide insight into both CPK- and SnRK-specific and overlapping signaling network architectures and recapitulate many known in vivo relationships validating this large-scale approach towards discovering kinase targets.
PubMed: 38891291
DOI: 10.3390/plants13111481 -
Foods (Basel, Switzerland) Jun 2024In this study, a novel strain for degrading chitin was identified as HL37, and the key chitinase CH1 was firstly mined through recombinant expression in HZ12....
In this study, a novel strain for degrading chitin was identified as HL37, and the key chitinase CH1 was firstly mined through recombinant expression in HZ12. Subsequently, the sequence composition and catalytic mechanism of CH1 protein were analyzed. The molecular docking indicated that the triplet of Asp526, Asp528, and Glu530 was a catalytic active center. The enzymatic properties analysis revealed that the optimal reaction temperature and pH was 65 °C and 6.0, respectively. Especially, the chitinase activity showed no significant change below 55 °C and it could maintain over 60% activity after exposure to 85 °C for 30 min. Moreover, the optimal host strain and signal peptide were obtained to enhance the expression of chitinase CH1 significantly. As far as we know, it was the first time finding the highly efficient chitin-degrading enzymes in , and detailed explanations were provided on the catalytic mechanism and enzymatic properties on CH1.
PubMed: 38891005
DOI: 10.3390/foods13111777 -
EBioMedicine Jun 2024The accuracy of blood-based early tumour recognition is compromised by signal production at non-tumoral sites, low amount of signal produced by small tumours, and...
BACKGROUND
The accuracy of blood-based early tumour recognition is compromised by signal production at non-tumoral sites, low amount of signal produced by small tumours, and variable tumour production. Here we examined whether tumour-specific enhancement of vascular permeability by the particular tumour homing peptide, iRGD, which carries dual function of binding to integrin receptors overexpressed in the tumour vasculature and is known to promote extravasation via neuropilin-1 receptor upon site-specific cleavage, might be useful to improve blood-based tumour detection by inducing a yet unrecognised vice versa tumour-to-blood transport.
METHODS
To detect an iRGD-induced tumour-to-blood transport, we examined the effect of intravenously injected iRGD on blood levels of α-fetoprotein (AFP) and autotaxin in several mouse models of hepatocellular carcinoma (HCC) or in mice with chronic liver injury without HCC, and on prostate-specific antigen (PSA) levels in mice with prostate cancer.
FINDINGS
Intravenously injected iRGD rapidly and robustly elevated the blood levels of AFP in several mouse models of HCC, but not in mice with chronic liver injury. The effect was primarily seen in mice with small tumours and normal basal blood AFP levels, was attenuated by an anti-neuropilin-1 antibody, and depended on the concentration gradient between tumour and blood. iRGD treatment was also able to increase blood levels of autotaxin in HCC mice, and of PSA in mice with prostate cancer.
INTERPRETATION
We conclude that iRGD induces a tumour-to-blood transport in a tumour-specific fashion that has potential of improving diagnosis of early stage cancer.
FUNDING
Deutsche Krebshilfe, DKTK, LOEWE-Frankfurt Cancer Institute.
PubMed: 38889481
DOI: 10.1016/j.ebiom.2024.105178 -
Proceedings of the National Academy of... Jun 2024Germ cells are regulated by local microenvironments (niches), which secrete instructive cues. Conserved developmental signaling molecules act as niche-derived regulatory...
Germ cells are regulated by local microenvironments (niches), which secrete instructive cues. Conserved developmental signaling molecules act as niche-derived regulatory factors, yet other types of niche signals remain to be identified. Single-cell RNA-sequencing of sexual planarians revealed niche cells expressing a nonribosomal peptide synthetase (). Inhibiting led to loss of female reproductive organs and testis hyperplasia. Mass spectrometry detected the dipeptide β-alanyl-tryptamine (BATT), which is associated with reproductive system development and requires and a monoamine-transmitter-synthetic enzyme Aromatic L-amino acid decarboxylase (AADC) for its production. Exogenous BATT rescued the reproductive defects after or inhibition, restoring fertility. Thus, a nonribosomal, monoamine-derived peptide provided by niche cells acts as a critical signal to trigger planarian reproductive development. These findings reveal an unexpected function for monoamines in niche-germ cell signaling. Furthermore, given the recently reported role for BATT as a male-derived factor required for reproductive maturation of female schistosomes, these results have important implications for the evolution of parasitic flatworms and suggest a potential role for nonribosomal peptides as signaling molecules in other organisms.
Topics: Animals; Planarians; Female; Male; Peptide Synthases; Sexual Development; Peptides; Reproduction; Signal Transduction
PubMed: 38889152
DOI: 10.1073/pnas.2321349121 -
Frontiers in Immunology 2024Inflammation is involved in the pathogenesis of diabetes, however the impact of diabetes on organ-specific autoimmune diseases remains unexplored. Experimental...
PURPOSE
Inflammation is involved in the pathogenesis of diabetes, however the impact of diabetes on organ-specific autoimmune diseases remains unexplored. Experimental autoimmune uveoretinitis (EAU) is a widely accepted animal model of human endogenous uveitis. In this study, we investigated the effects of diabetic conditions on the development of EAU using a mouse diabetes model.
METHODS
EAU was induced in wild-type C57BL/6 (WT) mice and Ins2 (Akita) mice with spontaneous diabetes by immunization with IRBP peptide. Clinical and histopathological examinations, and analysis of T cell activation state were conducted. In addition, alternations in the composition of immune cell types and gene expression profiles of relevant immune functions were identified using single-cell RNA sequencing.
RESULTS
The development of EAU was significantly attenuated in immunized Akita (Akita-EAU) mice compared with immunized WT (WT-EAU) mice, although T cells were fully activated in Akita-EAU mice, and the differentiation into Th17 cells and regulatory T (Treg) cells was promoted. However, Th1 cell differentiation was inhibited in Akita-EAU mice, and single-cell analysis indicated that gene expression associated AP-1 signaling pathway (JUN, FOS, and FOSB) was downregulated not only in Th1 cells but also in Th17, and Treg cells in Akita-EAU mice at the onset of EAU.
CONCLUSIONS
In diabetic mice, EAU was significantly attenuated. This was related to selective inhibition of Th1 cell differentiation and downregulated AP-1 signaling pathway in both Th1 and Th17 cells.
Topics: Animals; Uveitis; Th17 Cells; Th1 Cells; Mice; Signal Transduction; Transcription Factor AP-1; Cell Differentiation; Autoimmune Diseases; Mice, Inbred C57BL; Diabetes Mellitus, Experimental; Disease Models, Animal; Female
PubMed: 38887289
DOI: 10.3389/fimmu.2024.1347018 -
BMC Cardiovascular Disorders Jun 2024The purpose of this study was to investigate the diagnostic and prognostic value of miR-320a-3p in chronic heart failure (CHF).
AIM
The purpose of this study was to investigate the diagnostic and prognostic value of miR-320a-3p in chronic heart failure (CHF).
METHODS
A total of 103 patients with CHF and 95 healthy controls were included in the study population. The expression level of serum miR-320a-3p was detected by qRT-PCR. The diagnostic effect of miR-320a-3p on CHF was evaluated by receiver operating characteristic curve. Kaplan-Meier curve and Cox regression were used to analyze the risk factors for 4-year prognosis of CHF patients. Bioinformatics analysis was used to analyze the possible target genes of miR-320a-3p and related signaling pathways.
RESULTS
Serum miR-320a-3p expression was increased in CHF patients, and the levels of BNP and LVEF were positively and negatively correlated with miR-320a-3p, respectively. The AUC value of ROC curve was 0.866, indicating that miR-320a-3p had high diagnostic accuracy for CHF. Survival curve and Cox analysis showed that high expression of miR-320a-3p was associated with poor prognosis in CHF patients, and age and miR-320a-3p were independent risk factors for prognosis in CHF patients. GO and KEGG analysis showed that the downstream target genes of miR-320a-3p were involved in biological processes such as cell adhesion, stem cell differentiation and neural development, and were enriched in mTOR, TNF, AMPK and other signaling pathways.
CONCLUSIONS
miR-320a-3p increased abnormally in CHF and was related to the severity of CHF. miR-320a-3p has the potential to be a diagnostic and prognostic marker for CHF.
Topics: Humans; MicroRNAs; Heart Failure; Male; Female; Middle Aged; Prognosis; Aged; Chronic Disease; Case-Control Studies; Predictive Value of Tests; Stroke Volume; Ventricular Function, Left; Risk Factors; Risk Assessment; Time Factors; Signal Transduction; Natriuretic Peptide, Brain; Genetic Markers
PubMed: 38886631
DOI: 10.1186/s12872-024-03966-0 -
MedComm Jun 2024Spike-protein-based pseudotyped viruses were used to evaluate vaccines during the COVID-19 pandemic. However, they cannot be used to evaluate the envelope (E), membrane...
Spike-protein-based pseudotyped viruses were used to evaluate vaccines during the COVID-19 pandemic. However, they cannot be used to evaluate the envelope (E), membrane (M), and nucleocapsid (N) proteins. The first generation of virus-like particle (VLP) pseudotyped viruses contains these four structural proteins, but their titers for wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are relatively low, even lower for the omicron variant, rendering them unsuitable for neutralizing antibody detection. By optimizing the spike glycoprotein signal peptide, substituting the complexed M and E proteins with SARS-COV-1, optimizing the N protein with specific mutations (P199L, S202R, and R203M), and truncating the packaging signal, PS9, we increased the titer of the wild-type VLP pseudotyped virus over 100-fold, and successfully packaged the omicron VLP pseudotyped virus. The SARS-CoV-2 VLP pseudotyped viruses maintained stable titers, even through 10 freeze-thaw cycles. The key neutralization assay parameters were optimized, including cell type, cell number, and viral inoculum. The assay demonstrated minimal variation in both intra- and interassay results, at 11.5% and 11.1%, respectively. The correlation between the VLP pseudotyped virus and the authentic virus was strong ( = 0.9). Suitable for high-throughput detection of various mutant strains in clinical serum. In summary, we have developed a reliable neutralization assay for SARS-CoV-2 based on VLP pseudotyped virus.
PubMed: 38881676
DOI: 10.1002/mco2.615