Lipid bilayer induces contraction of the denatured state ensemble of a helical-bundle membrane protein.

Defining the denatured state ensemble (DSE) and disordered proteins is essential to understanding folding, chaperone action, degradation, and translocation. As compared with water-soluble proteins, the DSE of membrane proteins is much less characterized. Here, we measure the DSE of the helical membrane protein GlpG of Escherichia coli (E. coli) in native-like lipid bilayers. The DSE was obtained using our steric trapping method, which couples denaturation of doubly biotinylated GlpG to binding of two streptavidin molecules. The helices and loops are probed using limited proteolysis and mass spectrometry, while the dimensions are determined using our paramagnetic biotin derivative and double electron-electron resonance spectroscopy. These data, along with our Upside simulations, identify the DSE as being highly dynamic, involving the topology changes and unfolding of some of the transmembrane (TM) helices. The DSE is expanded relative to the native state but only to 15 to 75% of the fully expanded condition. The degree of expansion depends on the local protein packing and the lipid composition. E. coli's lipid bilayer promotes the association of TM helices in the DSE and, probably in general, facilitates interhelical interactions. This tendency may be the outcome of a general lipophobic effect of proteins within the cell membranes.

Syntheses of the ω-pyridinium-containing very-long-chain ceramides PyrCer(24:1(15Z)) and PyrCer(24:0) and their anticancer activity.

Ceramides, crucial sphingolipids in cellular biology, play various roles ranging from structural membrane integrity to signaling pathway regulation. Structurally, a ceramide consists of a fatty acid connected to a sphingoid base. The characteristics of the fatty acid chain, including length and saturation, determine the physiological properties of the ceramide. Ceramides typically fall into the following categories based on chain length: medium, long, very-long, and ultra-long. Among them, two very-long-chain ceramides, Cer(24:1(15Z)) and Cer(24:0), have been extensively studied, and they are known for their regulatory functions. However, the hydrophobic natures of ceramides, arising from their long hydrocarbon chain impedes their solubilities and levels of cellular delivery. Although ω-pyridinium ceramide analogs (ω-PyrCers) have been developed to address this issue, ω-PyrCers with very-long fatty acid chains or unsaturation have not been developed, presumably due to limited access to the corresponding ω-bromo fatty acids required in their syntheses. In this study, we prepared the ω-PyrCers of Cer(24:1(15Z)) and Cer(24:0), PyrCer(24:1(15Z)) and PyrCer(24:0), respectively. The key in the synthesis is the Wittig reaction to prepare the ω-bromo fatty acid with an appropriate chain length and (Z)-double bond position. Preliminary evaluation of the PyrCer(24:1(15Z)) and PyrCer(24:0) revealed their potential in hepatocellular carcinoma treatment.

The Role of Protein Methyltransferases in Immunity.

The immune system protects our body from bacteria, viruses, and toxins and removes malignant cells. Activation of immune cells requires the onset of a network of important signaling proteins. Methylation of these proteins affects their structure and biological function. Under stimulation, T cells, B cells, and other immune cells undergo activation, development, proliferation, differentiation, and manufacture of cytokines and antibodies. Methyltransferases alter the above processes and lead to diverse outcomes depending on the degree and type of methylation. In the previous two decades, methyltransferases have been reported to mediate a great variety of immune stages. Elucidating the roles of methylation in immunity not only contributes to understanding the immune mechanism but is helpful in the development of new immunotherapeutic strategies. Hence, we review herein the studies on methylation in immunity, aiming to provide ideas for new approaches.

Hepatic TREM2+ macrophages express matrix metalloproteinases to control fibrotic scar formation.

Liver cirrhosis is characterized by the extensive deposition of extracellular matrix such as fibril collagen, causing dysfunction and failure of the liver. Hepatic macrophages play pivotal roles in the transition from inflammatory to restorative properties upon hepatic injury. In particular, scar-associated macrophages (SAMacs) control liver fibrosis with the representative expression of matrix metalloproteinase (MMP). However, the heterogenic SAMac population has not been well characterized yet. This study profiled heterogeneous liver macrophages using public databases of single-cell transcriptomics and found T-cell immunoglobulin and mucin containing (TIM)4- macrophages exhibited elevated expression of MMPs. Scar-associated triggering receptor expressed on myeloid cells (TREM)2 was positively correlated with MMP expression, suggesting that TREM2+ subsets exert their fibrotic role via MMPs. During the progression of diet-induced nonalcoholic steatohepatitis and drug-induced liver cirrhosis, monocyte-derived TREM2+ macrophages accumulate in the liver with the distinct expression of MMPs. A noticeable expansion of MMP- and TREM2- double positive macrophages was observed in fibrotic scar regions. Consistently, the analysis of single-cell transcriptomics for human cirrhotic livers supported the theory that TREM2+ SAMacs are strongly associated with MMPs. The results could expand the understanding of liver fibrosis and SAMac, offering potential therapeutic approaches for liver cirrhosis.

MEK1/2 inhibition rescues neurodegeneration by TFEB-mediated activation of autophagic lysosomal function in a model of Alzheimer's Disease.

Alzheimer's Disease (AD) is a progressive neurodegenerative disorder, which is characterized by cognitive deficit due to synaptic loss and neuronal death. Extracellular amyloid ß plaques are one of the pathological hallmarks of AD. The autophagic lysosomal pathway is the essential mechanism to maintain cellular homeostasis by driving clearance of protein aggregates and is dysfunctional in AD. Here, we showed that inhibiting MEK/ERK signaling using a clinically available MEK1/2 inhibitor, trametinib (GSK1120212, SNR1611), induces the protection of neurons through autophagic lysosomal activation mediated by transcription factor EB (TFEB) in a model of AD. Orally administered trametinib recovered impaired neural structures, cognitive functions, and hippocampal long-term potentiation (LTP) in 5XFAD mice. Trametinib also reduced Aß deposition via induction of autophagic lysosomal activation. RNA-sequencing analysis revealed upregulation of autophagic lysosomal genes by trametinib administration. In addition, trametinib inhibited TFEB phosphorylation at Ser142 and promoted its nuclear translocation, which in turn induced autophagic lysosomal related genes, indicating that trametinib activates the autophagic lysosomal process through TFEB activation. From these observations, we concluded that MEK inhibition provides neuronal protection from the Aß burden by increasing autophagic lysosomal activity. Thus, MEK inhibition may be an effective therapeutic strategy for AD.

Structural cavities are critical to balancing stability and activity of a membrane-integral enzyme.

Packing interaction is a critical driving force in the folding of helical membrane proteins. Despite the importance, packing defects (i.e., cavities including voids, pockets, and pores) are prevalent in membrane-integral enzymes, channels, transporters, and receptors, playing essential roles in function. Then, a question arises regarding how the two competing requirements, packing for stability vs. cavities for function, are reconciled in membrane protein structures. Here, using the intramembrane protease GlpG of Escherichiacoli as a model and cavity-filling mutation as a probe, we tested the impacts of native cavities on the thermodynamic stability and function of a membrane protein. We find several stabilizing mutations which induce substantial activity reduction without distorting the active site. Notably, these mutations are all mapped onto the regions of conformational flexibility and functional importance, indicating that the cavities facilitate functional movement of GlpG while compromising the stability. Experiment and molecular dynamics simulation suggest that the stabilization is induced by the coupling between enhanced protein packing and weakly unfavorable lipid desolvation, or solely by favorable lipid solvation on the cavities. Our result suggests that, stabilized by the relatively weak interactions with lipids, cavities are accommodated in membrane proteins without severe energetic cost, which, in turn, serve as a platform to fine-tune the balance between stability and flexibility for optimal activity.

Coinfection of Severe Fever With Thrombocytopenia Syndrome Virus and Coxiella burnetii in Developmental Stage of Hard Ticks in Subtropical Region of Korea.

BACKGROUND: Severe fever with thrombocytopenia syndrome virus (SFTSV) is transmitted through tick bites. Ticks are potential vectors for the bacterium Coxiella burnetii that causes Query fever. Here, we analyzed SFTSV and C. burnetii co-infection rates in ticks in rural areas of Jeju Island, South Korea. METHODS: Free ticks were collected from the natural environment of the island between 2016 and 2019, and SFTSV RNA was extracted. Additionally, ribosomal RNA gene sequencing was used to identify Coxiella species. RESULTS: Haemaphysalis longicornis was the most common tick species followed by H. flava. Tick number gradually increased from April, peaked in August, and was lowest in March. Of all the collected ticks, 82.6% (2,851/3,458) were nymphs, 17.9% (639/3,458) adults, and 0.1% (4/3,458) larvae. SFTSV-infected ticks comprised 12.6% of all ticks; their numbers were the lowest in November-December, increased from January, and were mostly identified in the adult stage during June-August. C. burnetii infections were detected in 4.4% of the SFTSV-infected H. longicornis ticks. C. burnetii co-infection was mainly observed in the nymph stage of H. longicornis, with the highest infection rate in January, followed by December and November. CONCLUSION: Our findings suggest that Jeju Island has a high SFTSV and potential C. burnetii infection in ticks. This study provides important insights regarding SFTS and Q fever risk to humans in South Korea.

Immunopharmacological Activities of Luteolin in Chronic Diseases.

Flavonoids have been shown to have anti-oxidative effects, as well as other health benefits (e.g., anti-inflammatory and anti-tumor functions). Luteolin (3', 4', 5,7-tetrahydroxyflavone) is a flavonoid found in vegetables, fruits, flowers, and herbs, including celery, broccoli, green pepper, navel oranges, dandelion, peppermint, and rosemary. Luteolin has multiple useful effects, especially in regulating inflammation-related symptoms and diseases. In this paper, we summarize the studies about the immunopharmacological activity of luteolin on anti-inflammatory, anti-cardiovascular, anti-cancerous, and anti-neurodegenerative diseases published since 2018 and available in PubMed or Google Scholar. In this review, we also introduce some additional formulations of luteolin to improve its solubility and bioavailability.

Apigenin: A Therapeutic Agent for Treatment of Skin Inflammatory Diseases and Cancer.

The skin is the main barrier between the body and the environment, protecting it from external oxidative stress induced by ultraviolet rays. It also prevents the entrance of infectious agents such as viruses, external antigens, allergens, and bacteria into our bodies. An overreaction to these agents causes severe skin diseases, including atopic dermatitis, pruritus, psoriasis, skin cancer, and vitiligo. Members of the flavonoid family include apigenin, quercetin, luteolin, and kaempferol. Of these, apigenin has been used as a dietary supplement due to its various biological activities and has been shown to reduce skin inflammation by downregulating various inflammatory markers and molecular targets. In this review, we deal with current knowledge about inflammatory reactions in the skin and the molecular mechanisms by which apigenin reduces skin inflammation.

Antioxidant, Anti-Inflammatory, Anti-Menopausal, and Anti-Cancer Effects of Lignans and Their Metabolites.

Since chronic inflammation can be seen in severe, long-lasting diseases such as cancer, there is a high demand for effective methods to modulate inflammatory responses. Among many therapeutic candidates, lignans, absorbed from various plant sources, represent a type of phytoestrogen classified into secoisolariciresionol (Seco), pinoresinol (Pino), matairesinol (Mat), medioresinol (Med), sesamin (Ses), syringaresinol (Syr), and lariciresinol (Lari). Lignans consumed by humans can be further modified into END or ENL by the activities of gut microbiota. Lignans are known to exert antioxidant and anti-inflammatory activities, together with activity in estrogen receptor-dependent pathways. Lignans may have therapeutic potential for postmenopausal symptoms, including cardiovascular disease, osteoporosis, and psychological disorders. Moreover, the antitumor efficacy of lignans has been demonstrated in various cancer cell lines, including hormone-dependent breast cancer and prostate cancer, as well as colorectal cancer. Interestingly, the molecular mechanisms of lignans in these diseases involve the inhibition of inflammatory signals, including the nuclear factor (NF)-κB pathway. Therefore, we summarize the recent in vitro and in vivo studies evaluating the biological effects of various lignans, focusing on their values as effective anti-inflammatory agents.

The Role of Thymoquinone in Inflammatory Response in Chronic Diseases.

Anti-inflammatory therapies have been shown to be effective in the prevention of various cardiovascular diseases, tumors, and cancer complications. Thymoquinone (TQ), the main active constituent of Nigella sativa, has shown promising therapeutic properties in many in vivo and in vitro models. However, TQ has poor bioavailability and is hydrophobic, prohibiting clinical trials with TQ alone. Studies have explored the combination of TQ with biological nanomaterials to improve its bioavailability. The TQ nanoparticle formulation shows better bioavailability than free TQ, and these formulations are ready for clinical trials to determine their potential as therapeutic agents. In this paper, we review current knowledge about the interaction between TQ and the inflammatory response and summarize the research prospects in Korea and abroad. We discuss the different biological activities of TQ and various combination therapies of TQ and nanomaterials in clinical trials.

Effect of herbal extracts and supplement mixture on alcohol metabolism in Sprague Dawley-rats.

This study aimed to investigate the effect of mixture of herbal extracts and supplementary formula (FNP-C) on hangovers and antioxidant enzymes in alcohol-induced liver damage in rats. HepG2 cells were used as the experimental cells and divided into five groups: non-treated control (normal), alcohol-induced control (control), mixture of herbal extracts (FNP-B), FNP-C, and a commercial treatment of liver diseases (Livers®); inhibition of detoxification and alcohol-induced damage was confirmed in vivo. Blood alcohol and acetaldehyde concentration after alcohol consumption were measured in a timely manner; alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), superoxide dismutase (SOD), glutathione (GSH), glutathione transferase (GST), and lactate dehydrogenase (LDH) levels were measured in the liver. FNP-C exhibited the highest effect. When FNP-C was administered to alcohol-induced animals, blood alcohol and acetaldehyde concentration decreased compared to FNP-B and Livers®. FNP-C reduced ADH levels and improved LDH, GSH, GST, and SOD levels. The FNP-C group was effective in preventing alcohol-induced hangovers and liver damage. Thus, FNP-C improves hangovers and increases antioxidant activity in an alcohol-induced model. Adding amino acids and vitamins to natural ingredients can potentially enhance the effect of improving hangovers.

Role of Zr6 Metal Nodes in Zr-Based Metal-Organic Frameworks for Catalytic Detoxification of Pesticides.

Pesticides are chemicals widely used for agricultural industry, despite their negative impact on health and environment. Although various methods have been developed for pesticide degradation to remedy such adverse effects, conventional materials often take hours to days for complete decomposition and are difficult to recycle. Here, we demonstrate the rapid degradation of organophosphate pesticides with a Zr-based metal-organic framework (MOF), showing complete degradation within 15 min. MOFs with different active site structures (Zr node connectivity and geometry) were compared, and a porphyrin-based MOF with six-connected Zr nodes showed remarkable degradation efficiency with half-lives of a few minutes. Such a high efficiency was further confirmed in a simple flow system for several cycles. This study reveals that MOFs can be highly potent heterogeneous catalysts for organophosphate pesticide degradation, suggesting that coordination geometry of the Zr node significantly influences the catalytic activity.

Role of Dendritic Cell in Diabetic Nephropathy.

Diabetic nephropathy (DN) is one of the most significant microvascular complications in diabetic patients. DN is the leading cause of end-stage renal disease, accounting for approximately 50% of incident cases. The current treatment options, such as optimal control of hyperglycemia and elevated blood pressure, are insufficient to prevent its progression. DN has been considered as a nonimmune, metabolic, or hemodynamic glomerular disease initiated by hyperglycemia. However, recent studies suggest that DN is an inflammatory disease, and immune cells related with innate and adaptive immunity, such as macrophage and T cells, might be involved in its development and progression. Although it has been revealed that kidney dendritic cells (DCs) accumulation in the renal tissue of human and animal models of DN require activated T cells in the kidney disease, little is known about the function of DCs in DN. In this review, we describe kidney DCs and their subsets, and the role in the pathogenesis of DN. We also suggest how to improve the kidney outcomes by modulating kidney DCs optimally in the patients with DN.

Olea europaea Suppresses Inflammation by Targeting TAK1-Mediated MAP Kinase Activation.

Possessing a variety of medicinal functions, Olea europaea L. is widely cultivated across the world. However, the anti-inflammatory mechanism of Olea europaea is not yet fully elucidated. In this study, how the methanol extract of the leaves of Olea europaea (Oe-ME) can suppress in vitro inflammatory responses was examined in terms of the identification of the target protein. RAW264.7 and HEK293T cells were used to study macrophage-mediated inflammatory responses and to validate the target protein using PCR, immunoblotting, nuclear fraction, overexpression, and cellular thermal shift assay (CETSA) under fixed conditions. Oe-ME treatment inhibited the mRNA expression levels of cyclooxygenase (COX)-2, matrix metallopeptidase (MMP)-9, and intercellular adhesion molecule-1 (ICAM-1) in activated RAW264.7 cells. Oe-ME diminished the activation of activator protein (AP)-1 and the phosphorylation of its upstream signaling cascades, including extracellular signal regulated kinase (ERK), mitogen-activated protein kinase kinase 1/2 (MEK1/2), c-Jun N-terminal kinase (JNK), mitogen-activated protein kinase kinase 3/6 (MKK3/6), p38, MKK7, and transforming growth factor-ß-activated kinase 1 (TAK1), in stimulated-RAW264.7 cells. Overexpression and CETSA were carried out to verify that TAK1 is the target of Oe-ME. Our results suggest that the anti-inflammatory effect of Oe-ME could be attributed to its control of posttranslational modification and transcription of TAK1.

Protective Effect of Potentilla glabra in UVB-Induced Photoaging Process.

Maintaining skin homeostasis is one of the most important factors for skin health. UVB-induced skin photoaging is a difficult problem that has negative impacts on skin homeostasis. So far, a number of compounds have been discovered that improve human skin barrier function and hydration, and are thought to be effective ways to protect skin homeostasis. Potentilla glabra var. mandshurica (Maxim.) Hand.-Mazz. Ethanol Extract (Pg-EE) is a compound that has noteworthy anti-inflammatory properties. However, its skin-protective effects are poorly understood. Therefore, we evaluated the capacity of Pg-EE to strengthen the skin barrier and improve skin hydration. Pg-EE can enhance the expression of filaggrin (FLG), transglutaminase (TGM)-1, hyaluronic acid synthase (HAS)-1, and HAS-2 in human keratinocytes. Moreover, Pg-EE down-regulated the expression of pro-inflammatory cytokines and up-regulated the production of FLG, HAS-1, and HAS-2 suppressed by UVB through inhibition of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways. Given the above, since Pg-EE can improve skin barrier, hydration and reduce the UVB-induced inflammation on skin, it could therefore be a valuable natural ingredient for cosmetics or pharmaceuticals to treat skin disorders.

TAK1/AP-1-Targeted Anti-Inflammatory Effects of Barringtonia augusta Methanol Extract.

Barringtonia augusta methanol extract (Ba-ME) is a folk medicine found in the wetlands of Thailand that acts through an anti-inflammatory mechanism that is not understood fully. Here, we examine how the methanol extract of Barringtonia augusta (B. augusta) can suppress the activator protein 1 (AP-1) signaling pathway and study the activities of Ba-ME in the lipopolysaccharide (LPS)-treated RAW264.7 macrophage cell line and an LPS-induced peritonitis mouse model. Non-toxic concentrations of Ba-ME downregulated the mRNA expression of cytokines, such as cyclooxygenase and chemokine ligand 12, in LPS-stimulated RAW264.7 cells. Transfection experiments with the AP-1-Luc construct, HEK293T cells, and luciferase assays were used to assess whether Ba-ME suppressed the AP-1 functional activation. A Western blot assay confirmed that C-Jun N-terminal kinase is a direct pharmacological target of Ba-ME action. The anti-inflammatory effect of Ba-ME, which functions by ß-activated kinase 1 (TAK1) inhibition, was confirmed by using an overexpression strategy and a cellular thermal shift assay. In vivo experiments in a mouse model of LPS-induced peritonitis showed the anti-inflammatory effect of Ba-ME on LPS-stimulated macrophages and acute inflammatory mouse models. We conclude that Ba-ME is a promising anti-inflammatory drug targeting TAK1 in the AP-1 pathway.

Activation of the alternative complement pathway predicts renal outcome in patients with lupus nephritis.

OBJECTIVES: The aims of this study were to clarify the activation of complement pathways in patients with lupus nephritis (LN), and to elucidate the association between these complement activation types and clinical outcomes. METHODS: We enrolled 115 patients with biopsy-proven LN from 2003 to 2016 from the lupus cohort at the Busan Paik Hospital and the Jeju National University Hospital in Korea. The patients were divided into two groups based on the patterns of glomerular complements deposits. The presence of C1q, C4 and/or C3 deposits in the glomerulus was considered evidence for the activation of the classical pathway with or without alternative pathway activation (group 1, N = 93), and glomerular C3 deposition without C1q and C4 deposits was considered as a marker for the alternative pathway limited activation (group 2, N = 22). The study end point was progression of kidney disease defined as a ≥50% reduction in estimated glomerular filtration rate from baseline values or advancement to end-stage renal disease. RESULTS: The mean estimated glomerular filtration rate and median urine protein-to-creatinine ratio of the patients were 85.7 ± 32.4 mL/min/1.73 m2 and 3.1 g/g, respectively, at the time of kidney biopsy. Forty-nine patients (43%) had nephrotic range of proteinuria. Compared to group 1 patients, those in group 2 were older, were more likely to be males and were more hypertensive. In addition, plasma C3 and C4 levels were significantly lower in group 1 patients compared to those in group 2. Moreover, anti-dsDNA concentration was significantly higher in group 1 patients compared to those in group 2. The mean follow-up time was 5.4 ± 3.4 years. The rates of response to one-year immunosuppressive treatment were poorer in group 2 patients compared to those in group 1. During the follow-up time, the progression of kidney disease was significantly higher in group 2 than in group 1 patients. CONCLUSION: This study showed that there was alternative complement pathway limited activation in the renal tissue in a small number of patients with LN, and these patients had worse renal outcomes compared to patients with glomerular classical complement pathway activation with or without alternative pathway activation.

Enhanced Photocatalytic Performance of Nanosized Mixed-Ligand Metal-Organic Frameworks through Sequential Energy and Electron Transfer Process.

Effective sequestration of harmful organic pollutants from wastewater has been a persistent concern in the interest of environmental and ecological protection from pollution and hazards. Currently, common water treatment technologies such as adsorption, coagulation, and membranes are expensive and not greatly effective. A new class of organic and inorganic composite metal-organic frameworks (MOFs) has emerged as an essential class of materials for numerous applications, including photocatalytic degradation of organic pollutants. Herein, we present a nanosize mixed-ligand MOF (nMLM) which was successfully synthesized by reacting a Zr metal source with a mixture of pyrene and porphyrin building units and further utilized as photocatalyst in the photodegradation of rhodamine B (RhB). The nMLM MOF showed excellent photocatalytic efficiency, which was due to the complementary absorption and sequential energy and electron transfer properties of its building blocks, pyrene and porphyrin. We also propose herein a possible mechanism of the photocatalytic function of the material.

Activating mutations and translocations in the guanine exchange factor VAV1 in peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis and for which genetic mechanisms of transformation remain incompletely understood. Using RNA sequencing and targeted sequencing, here we identify a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7) in PTCL. Mechanistically these genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support a driver oncogenic role for VAV1 signaling in the pathogenesis of PTCL.