scholarly journals (p)ppGpp and Its Role in Bacterial Persistence: New Challenges

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Olga Pacios ◽  
Lucia Blasco ◽  
Inés Bleriot ◽  
Laura Fernandez-Garcia ◽  
Antón Ambroa ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Osmotic Shock ◽  
Carbon Sources ◽  
Stringent Response ◽  
Temperature Shift ◽  
Bacterial Persistence ◽  
Development Of Resistance ◽  
Wide Range ◽  
Antibiotic Failure

ABSTRACT Antibiotic failure not only is due to the development of resistance by pathogens but can also often be explained by persistence and tolerance. Persistence and tolerance can be included in the “persistent phenotype,” with high relevance for clinics. Two of the most important molecular mechanisms involved in tolerance and persistence are toxin-antitoxin (TA) modules and signaling via guanosine pentaphosphate/tetraphosphate [(p)ppGpp], also known as “magic spot.” (p)ppGpp is a very important stress alarmone which orchestrates the stringent response in bacteria; hence, (p)ppGpp is produced during amino acid or fatty acid starvation by proteins belonging to the RelA/SpoT homolog family (RSH). However, (p)ppGpp levels can also accumulate in response to a wide range of signals, including oxygen variation, pH downshift, osmotic shock, temperature shift, or even exposure to darkness. Furthermore, the stringent response is not only involved in responses to environmental stresses (starvation for carbon sources, fatty acids, and phosphates or heat shock), but it is also used in bacterial pathogenesis, host invasion, and antibiotic tolerance and persistence. Given the exhaustive and contradictory literature surrounding the role of (p)ppGpp in bacterial persistence, and with the aim of summarizing what is known so far about the magic spot in this bacterial stage, this review provides new insights into the link between the stringent response and persistence. Moreover, we review some of the innovative treatments that have (p)ppGpp as a target, which are in the spotlight of the scientific community as candidates for effective antipersistence agents.

scholarly journals STAT3, a Hub Protein of Cellular Signaling Pathways, Is Triggered by β-Hexaclorocyclohexane

2018 ◽  
Vol 19 (7) ◽  
pp. 2108 ◽  
Author(s):  
Elisabetta Rubini ◽  
Fabio Altieri ◽  
Silvia Chichiarelli ◽  
Flavia Giamogante ◽  
Stefania Carissimi ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Cell Lines ◽  
Molecular Mechanisms ◽  
Cellular Signaling ◽  
Environmental Pollutants ◽  
Altered Expression ◽  
Exposed Population ◽  
Wide Range ◽  
Hepg2 Cell Lines

Background: Organochlorine pesticides (OCPs) are widely distributed in the environment and their toxicity is mostly associated with the molecular mechanisms of endocrine disruption. Among OCPs, particular attention was focused on the effects of β-hexaclorocyclohexane (β-HCH), a widely common pollutant. A detailed epidemiological study carried out on exposed population in the “Valle del Sacco” found correlations between the incidence of a wide range of diseases and the occurrence of β-HCH contamination. Taking into account the pleiotropic role of the protein signal transducer and activator of transcription 3 (STAT3), its function as a hub protein in cellular signaling pathways triggered by β-HCH was investigated in different cell lines corresponding to tissues that are especially vulnerable to damage by environmental pollutants. Materials and Methods: Human prostate cancer (LNCaP), human breast cancer (MCF-7 and MDA-MB 468), and human hepatoma (HepG2) cell lines were treated with 10 μM β-HCH in the presence or absence of specific inhibitors for different receptors. All samples were subjected to analysis by immunoblotting and RT-qPCR. Results and Conclusions: The preliminary results allow us to hypothesize the involvement of STAT3, through both its canonical and non-canonical pathways, in response to β-HCH. Moreover, we ascertained the role of STAT3 as a master regulator of energy metabolism via the altered expression and localization of HIF-1α and PKM2, respectively, resulting in a Warburg-like effect.

Molecular mechanisms of endolysosomal Ca2+ signalling in health and disease

2011 ◽  
Vol 439 (3) ◽  
pp. 349-378 ◽  
Author(s):  
Anthony J. Morgan ◽  
Frances M. Platt ◽  
Emyr Lloyd-Evans ◽  
Antony Galione
Keyword(s):  
Molecular Mechanisms ◽  
Cellular Processes ◽  
Late Endosomes ◽  
Wide Range ◽  
Health And Disease ◽  
Lysosome Related Organelles ◽  
Cellular Compartments ◽  
Endosomal Vesicles ◽  
Intracellular Targets

Endosomes, lysosomes and lysosome-related organelles are emerging as important Ca2+ storage cellular compartments with a central role in intracellular Ca2+ signalling. Endocytosis at the plasma membrane forms endosomal vesicles which mature to late endosomes and culminate in lysosomal biogenesis. During this process, acquisition of different ion channels and transporters progressively changes the endolysosomal luminal ionic environment (e.g. pH and Ca2+) to regulate enzyme activities, membrane fusion/fission and organellar ion fluxes, and defects in these can result in disease. In the present review we focus on the physiology of the inter-related transport mechanisms of Ca2+ and H+ across endolysosomal membranes. In particular, we discuss the role of the Ca2+-mobilizing messenger NAADP (nicotinic acid adenine dinucleotide phosphate) as a major regulator of Ca2+ release from endolysosomes, and the recent discovery of an endolysosomal channel family, the TPCs (two-pore channels), as its principal intracellular targets. Recent molecular studies of endolysosomal Ca2+ physiology and its regulation by NAADP-gated TPCs are providing exciting new insights into the mechanisms of Ca2+-signal initiation that control a wide range of cellular processes and play a role in disease. These developments underscore a new central role for the endolysosomal system in cellular Ca2+ regulation and signalling.

scholarly journals Regulation of ST6GAL1 sialyltransferase expression in cancer cells

Glycobiology ◽  
2020 ◽  
Author(s):  
Kaitlyn A Dorsett ◽  
Michael P Marciel ◽  
Jihye Hwang ◽  
Katherine E Ankenbauer ◽  
Nikita Bhalerao ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Translational Regulation ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Sialic Acids ◽  
Invasion Resistance ◽  
Cell Behaviors ◽  
Molecular Events ◽  
Wide Range

Abstract The ST6GAL1 sialyltransferase, which adds α2–6 linked sialic acids to N-glycosylated proteins, is overexpressed in a wide range of human malignancies. Recent studies have established the importance of ST6GAL1 in promoting tumor cell behaviors such as invasion, resistance to cell stress, and chemoresistance. Furthermore, ST6GAL1 activity has been implicated in imparting cancer stem cell characteristics. However, despite the burgeoning interest in the role of ST6GAL1 in the phenotypic features of tumor cells, insufficient attention has been paid to the molecular mechanisms responsible for ST6GAL1 upregulation during neoplastic transformation. Evidence suggests that these mechanisms are multifactorial, encompassing genetic, epigenetic, transcriptional, and post-translational regulation. The purpose of this review is to summarize current knowledge regarding the molecular events that drive enriched ST6GAL1 expression in cancer cells.

scholarly journals The Role of Sirtuins in Kidney Diseases

2020 ◽  
Vol 21 (18) ◽  
pp. 6686
Author(s):  
Yu Ah Hong ◽  
Ji Eun Kim ◽  
Minjee Jo ◽  
Gang-Jee Ko
Keyword(s):  
Histone Deacetylases ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Kidney Diseases ◽  
Expression Profiles ◽  
Kidney Injury ◽  
Class Iii ◽  
Cellular Functions ◽  
Wide Range

Sirtuins (SIRTs) are class III histone deacetylases (HDACs) that play important roles in aging and a wide range of cellular functions. Sirtuins are crucial to numerous biological processes, including proliferation, DNA repair, mitochondrial energy homeostasis, and antioxidant activity. Mammals have seven different sirtuins, SIRT1–7, and the diverse biological functions of each sirtuin are due to differences in subcellular localization, expression profiles, and cellular substrates. In this review, we summarize research advances into the role of sirtuins in the pathogenesis of various kidney diseases including acute kidney injury, diabetic kidney disease, renal fibrosis, and kidney aging along with the possible underlying molecular mechanisms. The available evidence indicates that sirtuins have great potential as novel therapeutic targets for the prevention and treatment of kidney diseases.

scholarly journals Molecular Mechanisms of Liver Injury and Hepatocarcinogenesis: Focusing on the Role of Stress-Activated MAPK

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Hayato Nakagawa ◽  
Shin Maeda
Keyword(s):  
Liver Injury ◽  
Molecular Mechanisms ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Cellular Effects ◽  
Wide Range ◽  
Mitogen Activated Protein ◽  
Compensatory Proliferation

Hepatocellular carcinoma (HCC) is the third most common cause of cancer mortality. Short-term prognosis of patients with HCC has improved recently due to advances in early diagnosis and treatment, but long-term prognosis is still unsatisfactory. Therefore, obtaining a further understanding of the molecular carcinogenic mechanisms and the unique pathogenic biology of HCC is important. The most characteristic process in hepatocarcinogenesis is underlying chronic liver injury, which leads to repeated cycles of hepatocyte death, inflammation, and compensatory proliferation and subsequently provides a mitogenic and mutagenic environment leading to the development of HCC. Recent in vivo studies have shown that the stress-activated mitogen-activated protein kinase (MAPK) cascade converging on c-Jun NH2-terminal kinase (JNK) and p38 plays a central role in these processes, and it has attracted considerable attention as a therapeutic target. However, JNK and p38 have complex functions and a wide range of cellular effects. In addition, crosstalk with each other and the nuclear factor-kappaB pathway further complicate these functions. A full understanding is essential to bring these observations into clinical settings. In this paper, we discuss the latest findings regarding the mechanisms of liver injury and hepatocarcinogenesis focusing on the role of the stress-activated MAPK pathway.

scholarly journals The Role of Non-Coding RNAs in the Sorafenib Resistance of Hepatocellular Carcinoma

2021 ◽  
Vol 11 ◽  
Author(s):  
Xinyao Hu ◽  
Hua Zhu ◽  
Yang Shen ◽  
Xiaoyu Zhang ◽  
Xiaoqin He ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Molecular Mechanisms ◽  
Vital Role ◽  
Circular Rnas ◽  
First Line ◽  
Advanced Hcc ◽  
Chemotherapy Agent ◽  
Development Of Resistance ◽  
Non Coding Rnas

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death. Sorafenib is approved by the U.S. Food and Drug Administration to be a first-line chemotherapy agent for patients with advanced HCC. A portion of advanced HCC patients can benefit from the treatment with sorafenib, but many patients ultimately develop sorafenib resistance, leading to a poor prognosis. The molecular mechanisms of sorafenib resistance are sophisticated and indefinite. Notably, non-coding RNAs (ncRNAs), which include long ncRNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs), are critically participated in the occurrence and progression of tumors. Moreover, growing evidence has suggested that ncRNAs are crucial regulators in the development of resistance to sorafenib. Herein, we integrally and systematically summarized the molecular mechanisms and vital role of ncRNAs impact sorafenib resistance of HCC, and ultimately explored the potential clinical administrations of ncRNAs as new prognostic biomarkers and therapeutic targets for HCC.

scholarly journals Uncover TET1 Targets in MLL -Rearranged Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3632-3632
Author(s):  
Hengyou Weng ◽  
Huilin Huang ◽  
He Huang ◽  
Okwang Kwon ◽  
Ping Chen ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Molecular Mechanisms ◽  
Isotope Labeling ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Dna Demethylation ◽  
In Vivo Models ◽  
A Genome ◽  
Wide Range

Abstract 5-hydroxymethylcytosine (5hmC), also called the "sixth DNA base", is involved in the DNA demethylation process which generally leads to gene activation. Formation of 5hmC is catalyzed by the Ten-Eleven-Translocation (TET) family proteins, with TET1 being the founding member. The expression of TET1 protein and the global level of its enzymatic product, 5hmC, is markedly reduced in a wide range of solid tumors, including melanoma, prostate, breast, lung, and liver cancer, suggesting that TET1 functions as a tumor suppressor in these types of cancers. However, a recent study from our group demonstrated that TET1 expression and the associated 5hmC levels are significantly up-regulated in MLL -rearranged leukemia, revealing the oncogenic role of TET1 in this type of acute myeloid leukemia (AML) (Huang H, et al. PNAS 2013; 110(29):11994-9). In support of this, another study from a different group showed that high 5hmC level is an independent predictor of poor overall survival in patients with AML (Kroeze LI, et al. Blood 2014; 124(7):1110-8). However, how TET1, as a critical methylcytosine dioxygenase, plays its oncogenic role in AML, especially in MLL -rearranged leukemia, is still unclear. To address this issue, we performed stable isotope labeling by amino acids in cell culture (SILAC)-based proteomic profiling to systematically explore the functional targets of TET1 in a genome-wide and unbiased way. When TET1 was knocked down in MLL-ENL-estrogen receptor inducible (ERtm) mouse myeloid leukemia cells, 123 proteins were found downregulated whereas 191 were upregulated with a fold-change cutoff of 1.2. The expression changes of a set of these genes were confirmed by quantitative PCR in MLL-ENL-ERtm cells and mice samples with TET1 knock-down or depletion. After taking into account the correlation of TET1 and its candidate targets in several sets of AML patient samples, we focused on IDH1 and PSIP1, which represent the negatively- and positively-regulated targets by TET1, respectively. IDH1 encodes an isocitrate dehydrogenase whose mutations are frequently found in AML, whereas the PSIP1 protein is shown to be required for both MLL-dependent transcription and leukemic transformation. Chromatin immunoprecipitation (CHIP) assays suggest that TET1 directly binds to the CpG islands in the promoters of these two genes. Forced expression of Idh1 in leukemic bone marrow cells collected from mice developed MLL-AF9-driven AML significantly inhibited the colony-forming capacity of these cells, which mimics the effect of TET1 knock-out. We are now further investigating the functions and underlying molecular mechanisms of IDH1 and PSIP1 in AML using both in vitro and in vivo models. Considering the important roles of IDH1 and PSIP1 in AML, our findings will provide new insight into the mechanisms underlying the oncogenic role of TET1 in MLL -rearranged leukemia and may ultimately lead to the development of targeted therapy of AML. Disclosures No relevant conflicts of interest to declare.

scholarly journals Lipophilicity of Bacteriochlorin-Based Photosensitizers as a Determinant for PDT Optimization through the Modulation of the Inflammatory Mediators

2019 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Barbara Pucelik ◽  
Luis G. Arnaut ◽  
Janusz M. Dąbrowski
Keyword(s):  
Immune Response ◽  
Molecular Mechanisms ◽  
Near Infrared ◽  
Antitumor Immune Response ◽  
Infrared Light ◽  
Gm Csf ◽  
Hydrophobic Compound ◽  
Tnf Α ◽  
Wide Range

Photodynamic therapy (PDT) augments the host antitumor immune response, but the role of the PDT effect on the tumor microenvironment in dependence on the type of photosensitizer and/or therapeutic protocols has not been clearly elucidated. We employed three bacteriochlorins (F2BOH, F2BMet and Cl2BHep) of different polarity that absorb near-infrared light (NIR) and generated a large amount of reactive oxygen species (ROS) to compare the PDT efficacy after various drug-to-light intervals: 15 min. (V-PDT), 3h (E-PDT) and 72h (C-PDT). We also performed the analysis of the molecular mechanisms of PDT crucial for the generation of the long-lasting antitumor immune response. PDT-induced damage affected the integrity of the host tissue and developed acute (protocol-dependent) local inflammation, which in turn led to the infiltration of neutrophils and macrophages. In order to further confirm this hypothesis, a number of proteins in the plasma of PDT-treated mice were identified. Among a wide range of cytokines (IL-6, IL-10, IL-13, IL-15, TNF-α, GM-CSF), chemokines (KC, MCP-1, MIP1α, MIP1β, MIP2) and growth factors (VEGF) released after PDT, an important role was assigned to IL-6. PDT protocols optimized for studied bacteriochlorins led to a significant increase in the survival rate of BALB/c mice bearing CT26 tumors, but each photosensitizer (PS) was more or less potent, depending on the applied DLI (15 min, 3 h or 72 h). Hydrophilic (F2BOH) and amphiphilic (F2BMet) PSs were equally effective in V-PDT (>80 cure rate). F2BMet was the most efficient in E-PDT (DLI = 3h), leading to a cure of 65 % of the animals. Finally, the most powerful PS in the C-PDT (DLI = 72 h) regimen turned out to be the most hydrophobic compound (Cl2BHep), allowing 100 % of treated animals to be cured at a light dose of only 45 J/cm2.

scholarly journals The Kynurenine Pathway—New Linkage between Innate and Adaptive Immunity in Autoimmune Endocrinopathies

2021 ◽  
Vol 22 (18) ◽  
pp. 9879
Author(s):  
Anna Krupa ◽  
Irina Kowalska
Keyword(s):  
Immune System ◽  
Adaptive Immunity ◽  
Immune Cells ◽  
Molecular Mechanisms ◽  
Inflammatory Diseases ◽  
Kynurenine Pathway ◽  
Wide Range ◽  
Organ Specific ◽  
Autoimmune And Inflammatory Diseases

The kynurenine pathway (KP) is highly regulated in the immune system, where it promotes immunosuppression in response to infection or inflammation. Indoleamine 2,3-dioxygenase 1 (IDO1), the main enzyme of KP, has a broad spectrum of activity on immune cells regulation, controlling the balance between stimulation and suppression of the immune system at sites of local inflammation, relevant to a wide range of autoimmune and inflammatory diseases. Various autoimmune diseases, among them endocrinopathies, have been identified to date, but despite significant progress in their diagnosis and treatment, they are still associated with significant complications, morbidity, and mortality. The precise cellular and molecular mechanisms leading to the onset and development of autoimmune disease remain poorly clarified so far. In breaking of tolerance, the cells of the innate immunity provide a decisive microenvironment that regulates immune cells’ differentiation, leading to activation of adaptive immunity. The current review provided a comprehensive presentation of the known role of IDO1 and KP activation in the regulation of the innate and adaptive arms of the immune system. Significant attention has been paid to the immunoregulatory role of IDO1 in the most prevalent, organ-specific autoimmune endocrinopathies—type 1 diabetes mellitus (T1DM) and autoimmune thyroiditis.

The CXCL12/CXCR4/ACKR3 Axis in the Tumor Microenvironment: Signaling, Crosstalk, and Therapeutic Targeting

2021 ◽  
Vol 61 (1) ◽  
pp. 541-563 ◽  
Author(s):  
Martine J. Smit ◽  
Géraldine Schlecht-Louf ◽  
Maria Neves ◽  
Jelle van den Bor ◽  
Petronila Penela ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Immune Cells ◽  
Chemokine Receptors ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cancer Therapies ◽  
Signaling Crosstalk ◽  
Wide Range ◽  
Elevated Expression

Elevated expression of the chemokine receptors CXCR4 and ACKR3 and of their cognate ligand CXCL12 is detected in a wide range of tumors and the tumor microenvironment (TME). Yet, the molecular mechanisms by which the CXCL12/CXCR4/ACKR3 axis contributes to the pathogenesis are complex and not fully understood. To dissect the role of this axis in cancer, we discuss its ability to impinge on canonical and less conventional signaling networks in different cancer cell types; its bidirectional crosstalk, notably with receptor tyrosine kinase (RTK) and other factors present in the TME; and the infiltration of immune cells that supporttumor progression. We discuss current and emerging avenues that target the CXCL12/CXCR4/ACKR3 axis. Coordinately targeting both RTKs and CXCR4/ACKR3 and/or CXCL12 is an attractive approach to consider in multitargeted cancer therapies. In addition, inhibiting infiltrating immune cells or reactivating the immune system along with modulating the CXCL12/CXCR4/ACKR3 axis in the TME has therapeutic promise.

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