1,720,975 research outputs found
Hesperetin inhibit EMT in TGF-beta treated podocyte by regulation of mTOR pathway
No full textRenal fibrosis is one of the characteristic features of chronic kidney disease (CKD). Fibrotic change not only impairs the filtration function of the kidney but is also recognized as a marker of end-stage renal disease (ESRD). The epithelial to mesenchymal transition (EMT) is known to play a role in embryonic development and organ formation, but it is getting much attention for its pathological role in the invasion and metastasis of carcinoma. Recently, it has also been reported that EMT plays a role in the formation of fibrosis during chronic inflammation. EMT contribute to the development of the fibrosis in CKD. Moreover, glomerular podocytes and tubular epithelial cells can also undergo mesenchymal transition in CKD. Hesperetin is a flavonoid present in citrus and is well known for its antioxidant and anti-inflammatory properties. In this study, we investigated the effects of hesperetin on the EMT-elicited podocytes. First, we generated an EMT model by treating transforming growth factor (TGF)-beta1, a potent inducer of EMT to the podocytes. TGF-beta1 decreased the expression of epithelial markers such as nephrin, zonula occludens-1 (ZO-1), while it increased the mesenchymal markers, including fibronectin (FN), vimentin, and alpha-smooth muscle actin (alpha-SMA) in the podocytes. Hesperetin suppressed EMT-like changes elicited by TGF-beta1. Interestingly, hesperetin did not interfere with the Smad signaling-the classical TGF-beta signaling-pathway, which was confirmed by the experiment with smad 2/3 -/- podocytes. Instead, hesperetin suppressed EMT-like changes by inhibiting the mTOR pathway-one of the alternative TGF-beta signaling pathways. In conclusion, hesperetin has a protective effect on the TGF-beta1 elicited EMT-like changes of podocytes through regulation of mTOR pathway. It could be a good candidate for the suppression of kidney fibrosis in various CKD
Atm deficiency in the DNA polymerase beta null cerebellum results in cerebellar ataxia and Itpr1 reduction associated with alteration of cytosine methylation
No full textGenomic instability resulting from defective DNA damage responses or repair causes several abnormalities, including progressive cerebellar ataxia, for which the molecular mechanisms are not well understood. Here, we report a new murine model of cerebellar ataxia resulting from concomitant inactivation of POLB and ATM. POLB is one of key enzymes for the repair of damaged or chemically modified bases, including methylated cytosine, but selective inactivation of Polb during neurogenesis affects only a subpopulation of cortical interneurons despite the accumulation of DNA damage throughout the brain. However, dual inactivation of Polb and Atm resulted in ataxia without significant neuropathological defects in the cerebellum. ATM is a protein kinase that responds to DNA strand breaks, and mutations in ATM are responsible for Ataxia Telangiectasia, which is characterized by progressive cerebellar ataxia. In the cerebella of mice deficient for both Polb and Atm, the most downregulated gene was Itpr1, likely because of misregulated DNA methylation cycle. ITPR1 is known to mediate calcium homeostasis, and ITPR1 mutations result in genetic diseases with cerebellar ataxia. Our data suggest that dysregulation of ITPR1 in the cerebellum could be one of contributing factors to progressive ataxia observed in human genomic instability syndromes
Phosphorylation analysis of the Hippo-YAP pathway using Phos-tag
No full textPhosphorylation is an essential regulatory mechanism in cells that modifies diverse substrates, such as proteins, carbohydrates, lipids, and nucleotides. Protein phosphorylation regulates function, subcellular localization, and protein-protein interactions. Protein kinases and phosphatases catalyze this reversible mechanism, subsequently influencing signal transduction. The dysregulation of protein phosphorylation leads to many diseases, such as cancer, neurodegenerative diseases, and metabolic diseases. Therefore, analyzing the phosphorylation status and identifying protein phosphorylation sites are critical for elucidating the biological functions of specific phosphorylation events. Unraveling the critical phosphorylation events associated with diseases and specific signaling pathways is promising for drug discovery. To date, highly accurate and sensitive approaches have been developed to detect the phosphorylation status of proteins. In this review, we discuss the application of Phos-tag to elucidate the biological functions of Hippo pathway components, with emphasis on the identification and quantitation of protein phosphorylation under physiological and pathological conditions. SIGNIFICANCE: We here provide a comprehensive overview of Phos-tag technique-based strategies to identify phosphorylated proteins at the cellular level in the Hippo-YAP pathway that comprises a major driving force for cellular homeostasis. We clarify the links of applying Phos-tag in elucidating the biological functions of the Hippo pathway components with particular attention to the identification and quantitation of protein phosphorylation under physiological and pathological conditions. We believe that our paper will make a significant contribution to the literature because these detailed phosphorylation modifications and functional diversity of the Hippo pathway components in physiological and pathological processes are only beginning to come to the fore, highlighting the potential for discovering new therapeutic targets. Moreover, this line of research can provide further insight into the inextricable link between phos-tag applications as a molecular tool and cellular signaling modality, offering new directions for an integrated research program toward understanding cellular regulation at the molecular level. Given the broad research and practical applications, we believe that this paper will be of interest to the readership of your journal
Extracts of Perilla frutescens var. Acuta (Odash.) Kudo Leaves Have Antitumor Effects on Breast Cancer Cells by Suppressing YAP Activity
Full text linkYes-associated protein (YAP)/WW domain-containing transcription factor (TAZ) is critical for cell proliferation, survival, and self-renewal. It has been shown to play a crucial oncogenic role in many different types of tumors. In this study, we investigated the antitumor effect of the extracts of Perilla frutescens var. acuta (Odash.) Kudo leaves (PLE) on Hippo-YAP/TAZ signaling. PLE induced the phosphorylation of YAP/TAZ, thereby inhibiting their activity. In addition, the treatment suppresses YAP/TAZ transcriptional activity via the dissociation of the YAP/TAZ-TEAD complex. To elucidate the molecular mechanism of PLE in the regulation of YAP activity, we treated WT and cell lines with gene knockout (KO) for Hippo pathway components with PLE. The inhibitory effects of PLE on YAP-TEAD target genes were significantly attenuated in LATS1/2 KO cells. Moreover, we found the antitumor effect of PLE on MDA-MB-231 and BT549, both of which are triple-negative breast cancer (TNBC) cell lines. PLE reduced the viability of TNBC cells in a dose-dependent manner and induced cell apoptosis. Further, PLE inhibited the migration ability in MDA-MB-231 cells. This ability was weakened in YAP and TEAD-activated clones suggesting that the inhibition of migration by PLE is mainly achieved by regulating YAP activity. Taken together, the results of this study indicate that PLE suppressed cell growth and increased the apoptosis of breast cancer (BC) cells via inactivation of YAP activity in a LATS1/2-dependent manner
Synphilin-1 regulates mechanotransduction in rigidity sensing through interaction with zyxin
No full textBACKGROUND: Synphilin-1 has been studied extensively in the context of Parkinson's disease pathology. However, the biophysical functions of synphilin-1 remain unexplored. To investigate its novel functionalities herein, cellular traction force and rigidity sensing ability are analyzed based on synphilin-1 overexpression using elastomeric pillar arrays and substrates of varying stiffness. Molecular changes are analyzed using RNA sequencing-based transcriptomic and liquid chromatography-tandem mass spectrometry-based proteomic analyses. RESULTS: Synphilin-1 overexpression reduces cell area, with a decline of local contraction on elastomeric pillar arrays. Cells overexpressing synphilin-1 exhibit an impaired ability to respond to substrate rigidity; however, synphilin-1 knockdown restores rigidity sensing abilities. Integrated omics analysis and in silico prediction corroborate the phenotypic alterations induced by synphilin-1 overexpression at a biophysical level. Zyxin emerges as a novel synphilin-1 binding protein, and synphilin-1 overexpression reduces the nuclear translocation of yes-associated protein. CONCLUSION: These findings provide novel insights into the biophysical functions of synphilin-1, suggesting a potential protective role to the altered extracellular matrix, which may be relevant to neurodegenerative conditions such as Parkinson's disease
Persicaria senticosa extract mitigates ultraviolet B-induced photoaging by suppressing the mitogen-activated protein kinase/activator protein 1/matrix metalloproteinase 1 pathway in human keratinocytes and hairless mice
Full text linkUltraviolet (UV) irradiation has been identified as a key trigger for skin photoaging, characterized by the overproduction of matrix metalloproteinases (MMPs) and reactive oxygen species (ROS), along with the accelerated decomposition of extracellular matrix (ECM) proteins, ultimately contributing to the development of wrinkles. Persicaria senticosa (PS) extracts are recognized for their antioxidative properties and their importance in skin health. Nevertheless, there is a paucity of studies investigating the potential of PS in protecting the skin against photoaging. The present study aimed to assess the effectiveness of PS extracts in preventing photoaging and elucidating the molecular mechanisms involved in using immortalized human keratinocytes (HaCaT) and hairless mice. The major bioactive constituents of PS were identified as p-coumaric acid, isoquercitrin, quercetin-3-O-glucuronide, and quercetin. Aqueous extracts of PS exhibited the ability to mitigate UVB-induced cellular damage and diminished ROS generation in HaCaT cells. Moreover, treatment with PS effectively attenuated the upregulated expression of matrix metalloproteinase-1 (MMP-1) and collagen degradation induced by UVB exposure. The property of PS to counteract photoaging was related to its capacity to inhibit the UVB-induced phosphorylation of mitogen-activated protein kinase (MAPK) and suppress the subsequent activation of activator protein 1 (AP-1) signaling pathways. Moreover, in hairless mice exposed to UVB radiation, the application of PS significantly alleviated the development of skin wrinkles, diminished epidermal thickening, and mitigated collagen degradation. Notably, PS treatment resulted in the downregulation of the UVB-activated MAPK/AP-1/MMP-1 pathway in mouse skin tissues. These findings suggest that PS has the potential to serve as a therapeutic agent for treating photoaging, holding promises in both cosmeceutical and pharmaceutical applications
Targeting the Hippo pathway in Schwann cells ameliorates peripheral nerve degeneration via a polypharmacological mechanism
Full text linkPeripheral neuropathies (PNs) are common diseases in elderly individuals characterized by Schwann cell (SC) dysfunction and irreversible Wallerian degeneration (WD). Although the molecular mechanisms of PN onset and progression have been widely studied, therapeutic opportunities remain limited. In this study, we investigated the pharmacological inhibition of Mammalian Ste20-like kinase 1/2 (MST1/2) by using its chemical inhibitor, XMU-MP-1 (XMU), against WD. XMU treatment suppressed the proliferation, dedifferentiation, and demyelination of SCs in models of WD in vitro, in vivo, and ex vivo. As a downstream mediator of canonical and noncanonical Hippo/MST1 pathway activation, the mature microRNA (miRNA) let-7b and its binding partners quaking homolog (QKI)/nucleolin (NCL) modulated miRNA-mediated silencing of genes involved in protein transport. Hence, direct phosphorylation of QKI and NCL by MST1 might be critical for WD onset and pathogenesis. Moreover, p38α/mitogen-activated protein kinase 14 (p38α) showed a strong affinity for XMU, and therefore, it may be an alternative XMU target for controlling WD in SCs. Taken together, our findings provide new insights into the Hippo/MST pathway function in PNs and suggest that XMU is a novel multitargeted therapeutic for elderly individuals with PNs. © 2024 The Author(s)TRUEsciescopu
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Rosmarinic acid promotes cartilage regeneration through Sox9 induction via NF-κB pathway inhibition in mouse osteoarthritis progression
Full text linkBackground: The natural polyphenolic compound known as Rosmarinic acid (RosA) can be found in various plants. Although its potential health benefits have been extensively studied, its effect on osteoarthritis (OA) progression and cartilage regeneration function still needs to be fully elucidated in OA animal models. This study elucidated the effect of RosA on OA progression and cartilage regeneration. Methods: In vitro assessments were conducted using RT-PCR, qRT-PCR, Western blotting, and ELISA to measure the effects of RosA. The molecular mechanisms of RosA were determined by analyzing the translocation of p65 into the nucleus using immunocytochemistry (ICC). Histological analysis of cartilage explant was performed using alcian blue staining and immunohistochemistry (IHC). For in vivo analysis, the destabilization of the medial meniscus (DMM)-induced OA mouse model was utilized to evaluate cartilage destruction through Safranin-O staining. The expression of catabolic and anabolic factors in mice knee joints was quantified by immunohistochemistry. Results: The expression of catabolic factors in chondrocytes was significantly impeded by RosA. It also suppressed the NF-κB signaling pathway by decreasing phosphorylation of p65 and reducing degradation of IκB protein. In ex vivo experiments, RosA protected sulfated proteoglycan erosion triggered by IL-1β and suppressed the catabolic factors in cartilage explant. RosA treatment in animal models resulted in preventing cartilage destruction and reducing catabolic factors in the cartilage. RosA was also found to promote the expression of Sox9, Col2a1, and Acan in vitro, ex vivo, and in vivo analyses. Conclusions: RosA attenuated the OA progression by suppressing the catabolic factors expression. These effects were facilitated through the suppression of the NF-κB signaling pathway. Additionally, it promotes cartilage regeneration by inducing anabolic factors. Therefore, RosA shows potential as an effective therapeutic agent for treating OA
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