Publications by authors named "Sam Seok Cho"

Article Synopsis
  • Hepatic stellate cells (HSCs) are key players in liver fibrosis, and the study investigates how CCCP, a mitochondrial uncoupler, affects mitophagy in these cells.
  • CCCP treatment leads to mitochondrial dysfunction in HSCs, evidenced by decreased mitochondrial function and increased reactive oxygen species (ROS), while also triggering mitophagy but disrupting its later stages due to lysosomal impairment.
  • The study found that CCCP elevates the fibrogenic marker plasminogen activator inhibitor-1 (PAI-1) in HSCs, which is linked to lysosomal dysfunction rather than changes in gene expression, suggesting that targeting CCCP-related pathways could be a potential strategy for treating liver fibrosis.
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Hepatic stellate cells (HSCs) play a role in hepatic fibrosis and sphingosine kinase (SphK) is involved in biological processes. As studies on the regulatory mechanisms and functions of SphK in HSCs during liver fibrosis are currently limited, this study aimed to elucidate the regulatory mechanism and connected pathways of SphK upon HSC activation. The expression of SphK1 was higher in HSCs than in hepatocytes, and upregulated in activated primary HSCs.

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Hepatic stellate cells (HSCs) are the main contributors to the development and progression of liver fibrosis. Parkin is an E3 ligase involved in mitophagy mediated by lysosomes that maintains mitochondrial homeostasis. Unfortunately, there is little information regarding the regulation of parkin by transforming growth factor-β (TGF-β) and its association with HSC trans-differentiation.

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(CS), a subtropical species, was reported to have antioxidant and antibacterial effects. However, the anti-inflammatory effects of CS have not been studied. This study aimed to investigate whether the 70% ethanol extract of the CS leaf (CSL3) inhibited lipopolysaccharide (LPS)-induced inflammatory responses and LPS and ATP-induced pyroptosis in macrophages.

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Ketone bodies have long been known as a group of lipid-derived alternative energy sources during glucose shortages. Nevertheless, the molecular mechanisms underlying their non-metabolic functions remain largely elusive. This study identified acetoacetate as the precursor for lysine acetoacetylation (Kacac), a previously uncharacterized and evolutionarily conserved histone post-translational modification.

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Ultraviolet B (UVB) rays disrupt the skin by causing photodamage via processes such as reactive oxygen species (ROS) production, endoplasmic reticulum (ER) stress, DNA damage, and/or collagen degradation. is an evergreen tree native to the southern Korean peninsula. Although it is known to have antioxidant and anti-inflammatory effects, its protective effect against photodamage in keratinocytes has not been investigated.

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Article Synopsis
  • * Treatment with ferroptosis inducers like RSL3 or erastin led to cell death in HSCs, while ferroptosis inhibitors were able to suppress this effect, indicating a crucial role for ferroptosis in HSC activation.
  • * In mouse models, iron accumulation induced ferroptosis and increased markers of fibrosis in the liver, aligning with findings in cirrhotic patient tissue, thereby suggesting ferroptosis is integral to both HSC activation and the progression of liver fibrosis.
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Article Synopsis
  • * The study focuses on Sirtuin 5 (SIRT5), a protein that hasn't been well-studied in cancer, showing that lower levels of SIRT5 correlate with more aggressive PCa and decreased survival.
  • * Researchers found that a specific modification of the lactate dehydrogenase A (LDHA) protein is linked to increased cancer cell movement and aggressiveness, suggesting that targeting SIRT5 and its effects on LDHA could help in treating advanced prostate cancer.
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Liver fibrosis is caused by repetitive hepatic injury. Regulated in development and DNA damage response 1 (REDD1) gene is induced by various stresses and has been studied in cell proliferation and survival. However, the role of REDD1 in hepatic stellate cell activation and hepatic fibrogenesis has not yet been investigated.

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Nonalcoholic fatty liver disease is the most common chronic disease affecting a wide range of the world's population and associated with obesity-induced metabolic syndrome. It is possibly emerging as a leading cause of life-threatening liver diseases for which a drug with a specific therapeutic target has not been developed yet. Previously, there have been reports on the benefits of (CT) for treating obesity and diabetes via regulation of metabolic processes, such as lipogenesis, lipolysis, and inflammation.

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Hepatic stellate cells (HSCs) are major contributors to hepatic fibrogenesis facilitating liver fibrosis. Forkhead box O 3a (FoxO3a) is a member of the forkhead transcription factor family, which mediates cell proliferation and differentiation. However, the expression and function of FoxO3a during HSC activation remain largely unknown.

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Ferroptosis is a widely recognized process of regulated cell death linking redox state, metabolism, and human health. It is considered a defense mechanism against extensive lipid peroxidation, a complex process that may disrupt the membrane integrity, eventually leading to toxic cellular injury. Ferroptosis is controlled by iron, reactive oxygen species, and polyunsaturated fatty acids.

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Context: 5-Caffeoylquinic acid (5-CQA) is one of the most abundant compounds found in natural foods including coffee.

Objective: We investigated whether 5-CQA had a cytoprotective effect through the NF-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) signalling pathway.

Materials And Methods: Nrf2 activation in response to 5-CQA treatment at the concentration of 10-100 μM is evaluated by Western blotting of Nrf2 and ARE reporter gene assay as well as its target gene expression in HepG2 cells.

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Neoagarooligosaccharides (NAOS) are generated by β-agarases, which cleave the β-1,4 linkage in agarose. Previously, we reported that NAOS inhibited fat accumulation in the liver and decreased serum cholesterol levels. However, the hepatoprotective effect of NAOS on acute liver injury has not yet been investigated.

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Hepatic stellate cells (HSCs) are essential for liver fibrosis. E6 associated protein (E6AP) is one of the E3-ubiquitin-protein ligase and has been studied in proliferation and cellular stress. Currently, no information is available on the role of E6AP on transforming growth factor-β (TGF-β) signaling and hepatic fibrogenesis.

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Article Synopsis
  • Ferroptosis is a type of cell death linked to oxidative stress and iron accumulation that affects cellular environments by inhibiting glutathione biosynthesis.
  • The protein Sestrin2 (Sesn2) is an antioxidant that responds to various cellular stresses and is controlled by stress-responsive factors like p53, Nrf2, and HIF-1α, although its role in ferroptosis is not widely understood.
  • The study found that ferroptosis inducers increase Sesn2 expression in liver cells, with Nrf2 playing a key role in this process, suggesting that Sesn2 may help protect against ferroptosis and related liver damage.
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The fruits, leaves, and roots of have been reported to contain large amounts of vitamin B, vitamin C, and flavonoids. They exhibit various physiological activities such as antitumor and anti-inflammatory effects. However, the hepatoprotective effects of extracts against oxidative stress-mediated liver injury have not yet been investigated.

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Hepatic fibrosis results from chronic liver injury and inflammatory responses. Sestrin 2 (Sesn2), an evolutionarily conserved antioxidant enzyme, reduces the severities of acute hepatitis and metabolic liver diseases. However, the role of Sesn2 in the pathogenesis of liver fibrosis remains obscure.

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This study was designed to investigate the hepatoprotective effect of bamboo stems using in vitro and in vivo experimental liver damage models. Ethyl acetate fraction of 80% ethanol extract of stem (PN3) containing polyphenols had a higher reporter gene activity as monitored by the activity of the NF-E2-related factor (Nrf2) antioxidant pathway in cells in comparison to extracts from other species and under other conditions. The Nrf2 was translocated from the cytosol to the nucleus in response to PN3, followed by induction of the Nrf2 target gene expression, including , , and in HepG2 cells.

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Regulated in development and DNA damage responses 1 (REDD1) is an inducible gene in response to various stresses, which functions as a negative regulator of the mammalian target of rapamycin protein kinase in complex 1. In the present study, we identified the role of REDD1 under the oxidative stress-mediated hepatocyte injury and its regulatory mechanism. REDD1 protein was increased in HO or tert-butylhydroperoxide (t-BHP)-treated hepatocytes HO also elevated REDD1 mRNA levels.

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Background & Aims: Hepatic stellate cells (HSCs) have a role in liver fibrosis. Guanine nucleotide-binding α-subunit 12 (Gα) converges signals from G-protein-coupled receptors whose ligand levels are elevated in the environment during liver fibrosis; however, information is lacking on the effect of Gα on HSC trans-differentiation. This study investigated the expression of Gα in HSCs and the molecular basis of the effects of its expression on liver fibrosis.

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The pro-inflammatory response and recruitment of macrophages into adipose tissue contribute to metabolic dysfunction. Here, we reported the anti-inflammatory and antiadipogenic effects of the methanol (MeOH) extract and ethyl acetate (EtOAc) fraction of bamboo leaf and its molecular mechanism in RAW264.7 cells and 3T3-L1 adipocytes, respectively.

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Endoplasmic reticulum (ER) stress is characterized by an accumulation of misfolded proteins, and ER stress reduction is essential for maintaining tissue homeostasis. However, the molecular mechanisms that protect cells from ER stress are not completely understood. The present study investigated the role of sestrin 2 (SESN2) on ER stress and sought to elucidate the mechanism responsible for the hepatoprotective effect of SESN2 in vitro and in vivo.

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Acetaminophen (APAP) overdose accounts for half of the cases of acute liver failure worldwide. We previously reported that Sestrin2 (Sesn2) protects against d-galactosamine/lipopolysaccharide-induced acute fulminant liver failure. In this study, we demonstrated that Sesn2 protects APAP-induced liver injury in mice, using a recombinant adenovirus encoding Sesn2 (Ad-Sesn2).

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The adipogenic transcriptional regulation was reported to inhibit transdifferentiation of hepatic stellate cells (HSCs), which constitute the main fibrogenic cell type in the liver. Lipin-1 exhibits a dual function: an enzyme that catalyzes the conversion of phosphatidate to diacylglycerol and a transcriptional regulator. However, the involvement of Lipin-1 in the regulation of transforming growth factor-β (TGF-β) signaling and fibrogenesis in HSCs is not fully understood.

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