Regulation Of Intracellular Signal Transduction Research Articles

Protein SUMOylation and Its Functional Role in Nuclear Receptor Control

Post-translational protein modifications (PTMs) significantly enhance the functional diversity of proteins and are therefore important for the expansion and the dynamics of the cell’s proteome. In addition to structurally simpler PTMs, substrates also undergo modification through the reversible attachment of small proteins. The best understood PTM of this nature to date is the covalent conjugation of ubiquitin and ubiquitin-like proteins (UBLs) to their substrates. The protein family of small ubiquitin-like modifier (SUMO) is one of these UBLs that has received increasing scientific attention. The pathway of SUMOylation is highly conserved in all eukaryotic cells and is crucial for their survival. It plays an essential role in many biological processes, such as the maintenance of genomic integrity, transcriptional regulation, gene expression, and the regulation of intracellular signal transduction, and thereby influences DNA damage repair, immune responses, cell cycle progression, and apoptosis. Several studies have already shown that in this context protein SUMOylation is involved in the control mechanisms of various cellular receptors. This article unites data from different studies focusing on the investigation of the strictly conserved three-step enzyme cascade of protein SUMOylation and the functional analysis of the involved proteins E1, E2, and E3 and SUMOylation target proteins. Furthermore, this review highlights the role of nuclear receptor SUMOylation and its importance for the cellular functionality and disease development arising from defects in correct protein SUMOylation.

S100a9 might act as a modulator of the Toll-like receptor 4 transduction pathway in chronic rhinosinusitis with nasal polyps

Chronic rhinosinusitis with nasal polyp (CRSwNP) is a highly prevalent disorder characterized by persistent nasal and sinus mucosa inflammation. Despite significant morbidity and decreased quality of life, there are limited effective treatment options for such a disease. Therefore, identifying causal genes and dysregulated pathways paves the way for novel therapeutic interventions. In the current study, a three-way interaction approach was used to detect dynamic co-expression interactions involved in CRSwNP. In this approach, the internal evolution of the co-expression relation between a pair of genes (X, Y) was captured under a change in the expression profile of a third gene (Z), named the switch gene. Subsequently, the biological relevancy of the statistically significant triplets was confirmed using both gene set enrichment analysis and gene regulatory network reconstruction. Finally, the importance of identified switch genes was confirmed using a random forest model. The results suggested four dysregulated pathways in CRSwNP, including “positive regulation of intracellular signal transduction”, “arachidonic acid metabolic process”, “spermatogenesis” and “negative regulation of cellular protein metabolic process”. Additionally, the S100a9 as a switch gene together with the gene pair {Cd14, Tpd52l1} form a biologically relevant triplet. More specifically, we suggested that S100a9 might act as a potential upstream modulator in toll-like receptor 4 transduction pathway in the major CRSwNP pathologies.

Differential tissue immune stimulation through immersion in bacterial and viral agonists in the Antarctic Notothenia rossii

The genome evolution of Antarctic notothenioids has been modulated by their extreme environment over millennia and more recently by human-caused constraints such as overfishing and climate change. Here we investigated the characteristics of the immune system in Notothenia rossii and how it responds to 8 h immersion in viral (Poly I:C, polyinosinic: polycytidylic acid) and bacterial (LPS, lipopolysaccharide) proxies. Blood plasma antiprotease activity and haematocrit were reduced in Poly I:C-treated fish only, while plasma protein, lysozyme activity and cortisol were unchanged with both treatments. The skin and duodenum transcriptomes responded strongly to the treatments, unlike the liver and spleen which had a mild response. Furthermore, the skin transcriptome responded most to the bacterial proxy (cell adhesion, metabolism and immune response processes) and the duodenum (metabolism, response to stress, regulation of intracellular signal transduction, and immune system responses) to the viral proxy. The differential tissue response to the two proxy challenges is indicative of immune specialisation of the duodenum and the skin towards pathogens. NOD-like and C-type lectin receptors may be central in recognising LPS and Poly I:C. Other antimicrobial compounds such as iron and selenium-related genes are essential defence mechanisms to protect the host from sepsis. In conclusion, our study revealed a specific response of two immune barrier tissue, the skin and duodenum, in Notothenia rossii when exposed to pathogen proxies by immersion, and this may represent an adaptation to pathogen infective strategies.

Utilizing In Silico Approaches to Investigate the Signaling Pathway's Crucial Function in Pennisetum glaucum Under Thermal Stress.

Pearl millet (Pennisetum glaucum (L.)) is a remarkable cereal crop known for its ability to thrive in challenging environmental conditions. Despite its resilience, the intricate molecular mechanisms behind its toughness remain a mystery. To address this knowledge gap, we conducted advanced next-generation RNA sequencing. This approach allowed us to compare the gene expression profiles of pearl millet seedlings exposed to heat stress with those grown under standard conditions. Our main focus was on the shoots of 13-day-old pearl millet plants, which we subjected to a brief heat stress episode at 50°C for 60 seconds. Within the vast genomic landscape comprising 36 041 genes, we successfully identified a set of 10 genes that exhibited significant fold changes, ranging from 11 to 14-fold compared to the control conditions. These 10 genes were previously unknown to have such substantial changes in expression compared to the control. To uncover the functional significance hidden within these transcriptomic findings, we utilized computational tools such as MEME, String, and phylogenetic tree analysis. These efforts collectively revealed conserved domains within the transcriptomic landscape, hinting at potential functions associated with these genetic sequences. Of particular note, the distinct transcriptomic patterns specific to pearl millet leaves under thermal stress shed light on intricate connections to fundamental biological processes. These processes included the Ethylene-activated signaling pathway, Regulation of intracellular signal transduction, Negative regulation of signal transduction, Protein autophosphorylation, and Intracellular signal transduction. Together, these processes provide insight into the molecular strategies employed by pearl millet to overcome thermal stress challenges. By integrating cutting-edge RNA sequencing techniques and computational analyses, we have embarked on unraveling the genetic components and pathways that empower pearl millet's resilience in the face of adversity. This newfound understanding has the potential to not only advance our knowledge of plant stress responses but also contribute to enhancing crop resilience in challenging environmental conditions.

The Role of Copper Homeostasis in Brain Disease.

In the human body, copper is an important trace element and is a cofactor for several important enzymes involved in energy production, iron metabolism, neuropeptide activation, connective tissue synthesis, and neurotransmitter synthesis. Copper is also necessary for cellular processes, such as the regulation of intracellular signal transduction, catecholamine balance, myelination of neurons, and efficient synaptic transmission in the central nervous system. Copper is naturally present in some foods and is available as a dietary supplement. Only small amounts of copper are typically stored in the body and a large amount of copper is excreted through bile and urine. Given the critical role of copper in a breadth of cellular processes, local concentrations of copper and the cellular distribution of copper transporter proteins in the brain are important to maintain the steady state of the internal environment. The dysfunction of copper metabolism or regulatory pathways results in an imbalance in copper homeostasis in the brain, which can lead to a myriad of acute and chronic pathological effects on neurological function. It suggests a unique mechanism linking copper homeostasis and neuronal activation within the central nervous system. This article explores the relationship between impaired copper homeostasis and neuropathophysiological progress in brain diseases.

Abstract 12552: Causal Effect of Exposure to Elevated Lipoprotein(a) Levels on the Blood Transcriptome : A Mendelian Randomization Study

INTRODUCTION: Lipoprotein(a) [Lp(a)] is one of the strongest genetic risk factors for atherosclerotic cardiovascular diseases (ASCVD). Several ex vivo studies have revealed a pro-inflammatory and pro-atherogenic role of Lp(a) in the etiology of ASCVD, mainly through induction of inflammation, metabolic processes, and apoptosis. However, whether Lp(a) causally influences the human transcriptome is unknown. Here, we aimed at identifying whether genetically-predicted Lp(a) levels could also affect the whole blood expression of genes involved in metabolic- and inflammatory-related pathways. Methods: We performed a series of inverse-variance weighted mendelian randomization analyses using single-nucleotide polymorphisms located in the LPA locus (±500kb; p<5x10 -8 ) from the UK Biobank GWAS on Lipoprotein(a) quantiles as exposure (n=377,590 and whole blood expression levels of 14,288 coding gene from eQTLGen as outcomes (n=31,684 from 37 studies). We then used the Functional Mapping and Annotation of Genome-Wide Association Studies tool (FUMA) to identify gene sets for cardiometabolic- and inflammatory-related pathways from gene ontology biological processes. Results: The MR analyses identified 1363 genes that may be causally influenced by exposure to high Lp(a) levels (with p<0.05). The 10 most strongly associated genes with genetically-predicted Lp(a) levels are FSTL3 , PRKC1 , PDE6C , PLXNB3 , SESN1 , SASH1 , CD1D , CCDC102A , SS18L1 and TCF12 . These genes are also differentially expressed in the heart. We identified 16 cardiometabolic-related pathways, mostly related to immune response, signaling, apoptosis, cardiovascular and vasculature development, cell proliferation, metabolic process, and catalytic activity. The 5 most significant pathways are regulation of cell population proliferation, regulation of intracellular signal transduction, positive regulation of cell population proliferation, cardiovascular system development and TOR signaling. Conclusions: Results of this study highlight a potentially causal effect of exposure to elevated Lp(a) levels on several key genes involved in metabolic processes and inflammation and provide mechanistic insight on the pathobiological role of Lp(a) in the etiology of ASCVD.

Therapeutic Role of Curcumin in Diabetes: An Analysis Based on Bioinformatic Findings

Background: Diabetes is an increasingly prevalent global disease caused by the impairment in insulin production or insulin function. Diabetes in the long term causes both microvascular and macrovascular complications that may result in retinopathy, nephropathy, neuropathy, peripheral arterial disease, atherosclerotic cardiovascular disease, and cerebrovascular disease. Considerable effort has been expended looking at the numerous genes and pathways to explain the mechanisms leading to diabetes-related complications. Curcumin is a traditional medicine with several properties such as being antioxidant, anti-inflammatory, anti-cancer, and anti-microbial, which may have utility for treating diabetes complications. This study, based on the system biology approach, aimed to investigate the effect of curcumin on critical genes and pathways related to diabetes. Methods: We first searched interactions of curcumin in three different databases, including STITCH, TTD, and DGIdb. Subsequently, we investigated the critical curated protein targets for diabetes on the OMIM and DisGeNET databases. To find important clustering groups (MCODE) and critical hub genes in the network of diseases, we created a PPI network for all proteins obtained for diabetes with the aid of a string database and Cytoscape software. Next, we investigated the possible interactions of curcumin on diabetes-related genes using Venn diagrams. Furthermore, the impact of curcumin on the top scores of modular clusters was analysed. Finally, we conducted biological process and pathway enrichment analysis using Gene Ontology (GO) and KEGG based on the enrichR web server. Results: We acquired 417 genes associated with diabetes, and their constructed PPI network contained 298 nodes and 1651 edges. Next, the analysis of centralities in the PPI network indicated 15 genes with the highest centralities. Additionally, MCODE analysis identified three modular clusters, which highest score cluster (MCODE 1) comprises 19 nodes and 92 edges with 10.22 scores. Screening curcumin interactions in the databases identified 158 protein targets. A Venn diagram of genes related to diabetes and the protein targets of curcumin showed 35 shared proteins, which observed that curcumin could strongly interact with ten of the hub genes. Moreover, we demonstrated that curcumin has the highest interaction with MCODE1 among all MCODs. Several significant biological pathways in KEGG enrichment associated with 35 shared included the AGE-RAGE signaling pathway in diabetic complications, HIF-1 signaling pathway, PI3K-Akt signaling pathway, TNF signaling, and JAK-STAT signaling pathway. The biological processes of GO analysis were involved with the cellular response to cytokine stimulus, the cytokine-mediated signaling pathway, positive regulation of intracellular signal transduction and cytokine production in the inflammatory response. Conclusion: Curcumin targeted several important genes involved in diabetes, supporting the previous research suggesting that it may have utility as a therapeutic agent in diabetes.

Discovery of novel targets and mechanisms of MEK inhibitor Selumetinib for LGG treatment based on molecular docking and molecular dynamics simulation

Based on molecular docking and molecular dynamics simulation, to find a new target and mechanism of MEK inhibitor Selumetinib in the treatment of low-grade glioma (LGG), and to provide theoretical guidance for its clinical medication. All possible targets of Selumetinib were fished through the compound target prediction database. New targets of Selumetinib in the treatment of LGG were found and its mechanism was evaluated employing molecular docking, gene difference analysis, molecular dynamics simulation, and protein subcellular localization prediction. A total of 100 Selumetinib targets and 85 LGG-related targets were screened in this study. There were 7 active targets at the intersection of the two. Through protein interaction (PPI), gene enrichment analysis, and gene difference analysis, one effective target of Selumetinib was finally screened, CDK2 mainly existing in the cytoplasm, endoplasmic reticulum, and plasma membrane; the target plays a role in the treatment of LGG by inhibiting the signal pathways of PI3K Akt and participating in biological processes such as peptide amino acid modification, regulation of intracellular signal transduction, and positive regulation of cell metabolism. CDK2 may be a new direction of Selumetinib in the clinical treatment of LGG.

EVOO Promotes a Less Atherogenic Profile Than Sunflower Oil in Smooth Muscle Cells Through the Extracellular Vesicles Secreted by Endothelial Cells.

BackgroundLittle is known about the effect of extra virgin olive (EVOO) and sunflower oil (SO) on the composition of extracellular vesicles (EVs) secreted by endothelial cells and the effects of these EVs on smooth muscle cells (SMCs). These cells play an important role in the development of atherosclerosis.MethodsWe evaluated the effects of endothelial cells-derived EVs incubated with triglyceride-rich lipoproteins obtained after a high-fat meal with EVOO (EVOO-EVs) and SO (SO-EVs), on the transcriptomic profile of SMCs.ResultsWe found 41 upregulated and 19 downregulated differentially expressed (DE)-miRNAs in EVOO-EVs. Afterwards, SMCs were incubated with EVOO-EVs and SO-EVs. SMCs incubated with SO-EVs showed a greater number of DE-mRNA involved in pathways related to cancer, focal adhesion, regulation of actin cytoskeleton, and MAPK, toll-like receptor, chemokine and Wnt signaling pathways than in SMCs incubated with EVOO-EVs. These DE-mRNAs were involved in biological processes related to the response to endogenous stimulus, cell motility, regulation of intracellular signal transduction and cell population proliferation.ConclusionEVOO and SO can differently modify the miRNA composition of HUVEC-derived EVs. These EVs can regulate the SMCs transcriptomic profile, with SO-EVs promoting a profile more closely linked to the development of atherosclerosis than EVOO-EVs.

Prospect of Using ERK1/2 and р38 in Regeneration-Competent Cells of Nervous Tissue as a Drug Targets for Treating Alzheimer’s Disease

Drugs used to treat Alzheimer's disease (AD) were developed taking into account the existing classic hypotheses of its pathogenesis (cholinergic, amyloid, and tau-protein pathological changes). However, these pharmaceuticals have shown rather low efficacy in clinical practice. Therefore, it is relevant to develop approaches for controlling neurogenesis in AD, primarily by synchronizing the activities of different cell compartments of the cellular renewal system of nerve tissue. The search for a solution to this problem is promising in the framework of the "Strategy for targeted pharmacological regulation of intracellular signal transduction in regeneration-competent cells." In this work, we studied the effects of the ERK1/2 and p38 inhibitors on nervous tissue progenitors and neuroglial cells' functioning under the conditions of modeling β-amyloid-induced neurodegeneration in vitro. We identified opposing changes in proliferation and differentiation of neural stem cells (NSCs) and neuronal-committed progenitors (NCPs) influenced by β-amyloid (Aβ). It was also found that different types of neuroglia cells' secretion of neurotrophic growth factors (astrocytes, oligodendrocytes, and microglia), when exposed to Aβ, differ in vector. The ERK1/2 and p38 inhibitors' ability to coordinate the functions of regeneration-competent cells of different types has been discovered. Under their influence, synchronization of pro-regenerative activity of NSCs, NCPs, as well as oligodendrocytes and microglial cells under conditions of β-amyloid-induced neurodegeneration was revealed. The results show the prospect of developing novel drugs to treat AD with ERK1/2 and p38 inhibitors.

Targeting JNK as a Novel Approach to Drug Metabolism Regulation

The management of pharmacokinetics and pharmacodynamics of drugs constitutes an approach for personalizing pharmacotherapy. This can be achieved by controlling xenobiotic metabolism. This research aimed to study the possibility of controlling the biotransformation of substances in the body through targeted regulation of intracellular signal transduction. By UPLC-MS/MS, the effect of JNK inhibitors on the metabolism of venlafaxine xenobiotic by liver cells was investigated in vitro. The blocking of JNK in hepatic homogenate cells containing the antidepressant was accompanied by an increase in the intensity of its biotransformation. There was a significant increase in forming a single pharmacologically active metabolite of O-desmethylvenlafaxine in the cell suspension and its further chemical conversion. Data from experiments indicate marked induction of venlafaxine metabolism by the JNK inhibitor. These properties of JNK inhibitors can be used to develop a novel approach to the characterization of antidepressant treatment. Also, the results indicate the prospect of studying activity modifiers of intracellular signaling molecules (in particular, mitogen-activated protein kinases) to develop methods of controlling the process of xenobiotic transformation and create a novel class of pharmaceuticals - targeted drug metabolism regulators.

Transcriptome Analysis Identifies Strategies Targeting Immune Response-Related Pathways to Control Enterotoxigenic Escherichia coli Infection in Porcine Intestinal Epithelial Cells.

Enterotoxigenic Escherichia coli (ETEC) is an important cause of post-weaning diarrhea (PWD) worldwide, resulting in huge economic losses to the swine industry worldwide. In this study, to understand the pathogenesis, the transcriptomic analysis was performed to explore the biological processes (BP) in porcine intestinal epithelial J2 cells infected with an emerging ETEC strain isolated from weaned pigs with diarrhea. Under the criteria of |fold change| (FC) ≥ 2 and P < 0.05 with false discovery rate < 0.05, a total of 131 referenced and 19 novel differentially expressed genes (DEGs) were identified after ETEC infection, including 96 upregulated DEGs and 54 downregulated DEGs. The Gene Ontology (GO) analysis of DEGs showed that ETEC evoked BP specifically involved in response to lipopolysaccharide (LPS) and negative regulation of intracellular signal transduction. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that immune response-related pathways were mainly enriched in J2 cells after ETEC infection, in which tumor necrosis factor (TNF), interleukin 17, and mitogen-activated protein kinase (MAPK) signaling pathways possessed the highest rich factor, followed by nucleotide-binding and oligomerization domain-like receptor (NLRs), C-type lectin receptor (CLR), cytokine–cytokine receptor interaction, and Toll-like receptor (TLR), and nuclear factor kappa-B (NF-κB) signaling pathways. Furthermore, 30 of 131 referenced DEGs, especially the nuclear transcription factor AP-1 and NF-κB, participate in the immune response to infection through an integral signal cascade and can be target molecules for prevention and control of enteric ETEC infection by probiotic Lactobacillus reuteri. Our data provide a comprehensive insight into the immune response of porcine intestinal epithelial cells (IECs) to ETEC infection and advance the identification of targets for prevention and control of ETEC-related PWD.

Таргетная регуляция внутриклеточной сигнальной трансдукции в регенераторно-компетентных клетках

Представлено научно-теоретическое обоснование перспективности разработки оригинального направления таргетной терапии в регенеративной медицине — «Стратегии фармакологической регуляции внутриклеточной сигнальной трансдукции в регенераторно-компетентных клетках». Предлагается использование внутриклеточных сигнальных молекул, играющих важную роль в регуляции пролиферативно-дифференцировочного статуса прогениторных клеток и элементов микроокружения, в качестве мишеней для средств с регенеративной активностью. Избирательность стимуляции регенерации отдельных тканей при этом определяется особенностями внутриклеточной сигнализации в гистогенетически и функционально разнородных клетках-предшественниках и/или тканеспецифичностью экспрессии тех или иных типов и изоформ сигнальных белков. Дан обзор результатов собственных фундаментальных исследований по выявлению роли ряда сигнальных молекул (потенциальных мишеней) в регуляции клеточного цикла родоначальных клеток различных типов и в функционировании элементов тканевого микроокружения. На моделях некоторых патологических состояний (ЦНС, кожи и кроветворной ткани) продемонстрирована эффективность реализации предлагаемой концепции фармакотерапии. Полученные результаты имеют основополагающее значение для создания принципиально новых таргетных лекарственных средств для терапии заболеваний дегенеративного характера.

Targeted Regulation of Intracellular Signal Transduction in Regeneration-Competent Cells: A new Direction for Therapy in Regenerative Medicine

A scientific and theoretical justification for developing the original direction for targeted therapy in regenerative medicine - "Strategy of pharmacological regulation of intracellular signal transduction in regeneration-competent cells" is presented. It is proposed to use intracellular signaling molecules, which play an important role in regulating the proliferative and differentiation status of progenitors and microenvironment cells, as targets of drugs with regenerative activity. The selectivity of stimulation of the regeneration of individual tissues is determined by the peculiarities of intracellular signaling in different progenitor cells and/or tissue-specific expression of certain types and isoform signaling molecules. The results of their basic research on the role of some signaling molecules (potential targets) in regulating the cell cycle of the progenitors of different types and the functioning of the tissue microenvironment cells are given. Experimental models of some pathological conditions (CNS, skin, and hematopoietic tissue) show the effectiveness of implementing the proposed concept of pharmacotherapy. The results are fundamental to the creation of novel targeted drugs for the treatment of degenerative diseases.

Identification of biomarkers, pathways and potential therapeutic target for docetaxel resistant prostate cancer

ABSTRACT Docetaxel has been proved to provide survival benefit for advanced prostate cancer (PCa) patients. Resistance to docetaxel further reduces the survival of these patients. Herein, we performed a comprehensive bioinformatic analysis to identify differentially expressed genes (DEGs) between docetaxel sensitive and resistant PCa (DRPC) cell based on Gene Expression Omnibus (GEO) database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were applied for functional and pathway analysis of DEGs. The STRING database, cytoscape software and plug-in ‘cytoHubba’ were used to construct protein–protein interaction (PPI) networks and identify hub genes. Survival analysis were performed via GEPIA database. Finally, we conducted immune infiltration analysis by TIMER. A total of 460 DEGs were identified. GO functional analysis showed that these DEGs are mainly enriched in chemotaxis, negative regulation of intracellular signal transduction, and regulation of cell adhesion, positive regulation of inflammatory response, regulation of response to cytokine stimulus. According to the results of KEGG pathway analysis, these DEGs are mainly involved in signaling by Rho GTPases, Miro GTPases and RHOBTB3; interferon Signaling; arginine biosynthesis; PI3K-Akt signaling pathway; cytokine-cytokine receptor interaction; MAPK signaling pathway. Finally, CCNB1 and EZH2 were identified as prognostic hub genes and the expression of these two genes were associated with immune infiltration. The present study may helps to improve the understanding of the molecular mechanisms of DRPC and facilitate the selection of therapeutic and prognostic biomarkers for DRPC.

MiR-362 suppresses cervical cancer progression via directly targeting BAP31 and activating TGFβ/Smad pathway.

BAP31 (B‐cell receptor‐associated protein 31) is an important regulator of intracellular signal transduction and highly expressed in several cancer tissues or testicular tissues. Our previous study had revealed that elevated BAP31 plays a crucial role in the progress and metastasis of cervical cancer. Even so, the precise mechanism of abnormal BAP31 elevation in cervical cancer has not been fully elucidated. We revealed that the expression of BAP31 was mainly regulated by microRNA‐362 (miR‐362), which was markedly downregulated in cervical cancer tissues and negatively correlated with clinical tumor staging. Overexpression of miR‐362 inhibited cervical cancer cell proliferation and increased the proportion of apoptotic cells. Furthermore, miR‐362 reduced the tumor sizes and prolonged mice survival time in xenograft nude mice model. Finally, we demonstrated that the BAP31/SPTBN1 complex regulated tumor progression through the Smad 2/3 pathway under the control of miR‐362. Collectively, our findings demonstrated that miR‐362 could work as an anti‐oncomiR that inhibits proliferation and promotes apoptosis in cervical cancer cells via BAP31 and TGFβ/Smad pathway. Overexpression of miR‐362 might be a potential therapeutic strategy for cervical cancer.

CD36 plays a negative role in the regulation of lipophagy in hepatocytes through an AMPK-dependent pathway

Fatty acid translocase cluster of differentiation (CD36) is a multifunctional membrane protein that facilitates the uptake of long-chain fatty acids. Lipophagy is autophagic degradation of lipid droplets. Accumulating evidence suggests that CD36 is involved in the regulation of intracellular signal transduction that modulates fatty acid storage or usage. However, little is known about the relationship between CD36 and lipophagy. In this study, we found that increased CD36 expression was coupled with decreased autophagy in the livers of mice treated with a high-fat diet. Overexpressing CD36 in HepG2 and Huh7 cells inhibited autophagy, while knocking down CD36 expression induced autophagy due to the increased autophagosome formation in autophagic flux. Meanwhile, knockout of CD36 in mice increased autophagy, while the reconstruction of CD36 expression in CD36-knockout mice reduced autophagy. CD36 knockdown in HepG2 cells increased lipophagy and β-oxidation, which contributed to improving lipid accumulation. In addition, CD36 expression regulated autophagy through the AMPK pathway, with phosphorylation of ULK1/Beclin1 also involved in the process. These findings suggest that CD36 is a negative regulator of autophagy, and the induction of lipophagy by ameliorating CD36 expression can be a potential therapeutic strategy for the treatment of fatty liver diseases through attenuating lipid overaccumulation.

Strategy of Pharmacological Regulation of Intracellular Signal Transduction in Regeneration-Competent Cells.

The study focuses on the development of principally novel priority-oriented healthcare strategy - targeted therapy in regenerative medicine known as Strategy of Pharmacological Control over Intracellular Signal Transduction in Regeneration-Competent Cells. It implies selective action of promising drugs on specific key elements in the signaling cascade responsible for functional activity of various progenitor cells (including stem cells) and elements of tissue microenvironment. The results of pioneer studies are described that were aimed on revealing the peculiarities in signal transduction and the role of distinct signaling molecules (the potential targets) in the control of cell cycle and other functions of progenitor elements and regulatory cells of different types. The models of some pathological states were employed to demonstrate the possibility of effective implementation of the advanced pharmacotherapeutic concept. The developed theoretical and applied platform can be used to launch synthesis of principally novel preparations with regenerative activity.

Peptide-templated multifunctional nanoprobe for feasible electrochemical assay of intracellular kinase

Protein kinases play a critical role in regulation of intracellular signal transduction, whose aberrant expression is closely associated with various dangerous human diseases. In this paper, we propose a feasible electrochemical assay of intracellular kinase by incorporating peptide nanoprobe-assisted signal labeling and signal amplification. Protein kinase A (PKA)-specific peptide P1 is self-assembled on the surface of a gold electrode, serine of which could be phosphorylated with catalysis of PKA in the presence of adenosine-5′-triphosphate (ATP). Another artificial peptide P2 contains a short template for preparation of copper nanoparticles-based nanoprobe (P2-CuNPs) and provides arginine residues for specific recognition of phosphorylation site. After PKA-catalyzed phosphorylation, phosphorylated P1 specially binds with P2-CuNPs through ultra-stable phosphate-guanidine interaction, and thus results in amplified electrochemical response from surface-attached CuNPs. Our method demonstrates a satisfactory sensitivity toward PKA detection with a detection limit of 0.0019 U/mL, which is also successfully applied in intracellular PKA assay and inhibitory study with high specificity comparable to ELISA. Therefore, the facile method suggests a promising potential use in kinase-related biochemical fundamental research, disease diagnosis and drug discovery in the future.

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells.

The post-translational modifications of proteins are critical for the proper regulation of intracellular signal transduction. Among these modifications, small ubiquitin-related modifier (SUMO) is a ubiquitin-like protein that is covalently attached to the lysine residues of a variety of target proteins to regulate cellular processes, such as gene transcription, DNA repair, protein interaction and degradation, subcellular transport, and signal transduction. The most common approach to detecting protein SUMOylation is based on the expression and purification of recombinant tagged proteins in bacteria, allowing for an in vitro biochemical reaction which is simple and suitable for addressing mechanistic questions. However, due to the complexity of the process of SUMOylation in vivo, it is more challenging to detect and analyze protein SUMOylation in cells, especially when under endogenous conditions. A recent study by the authors of this paper revealed that endogenous retinoblastoma (Rb) protein, a tumor suppressor that is vital to the negative regulation of the cell cycle progression, is specifically SUMOylated at the early G1 phase. This paper describes a protocol for the detection and analysis of Rb SUMOylation under both endogenous and exogenous conditions in human cells. This protocol is appropriate for the phenotypical and functional investigation of the SUMO-modification of Rb, as well as many other SUMO-targeted proteins, in human cells.