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Pourliotopoulou E, Karampatakis T, Kachrimanidou M. Exploring the Toxin-Mediated Mechanisms in Clostridioides difficile Infection. Microorganisms 2024; 12:1004. [PMID: 38792835 PMCID: PMC11124097 DOI: 10.3390/microorganisms12051004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
Clostridioides difficile infection (CDI) is the leading cause of nosocomial antibiotic-associated diarrhea, and colitis, with increasing incidence and healthcare costs. Its pathogenesis is primarily driven by toxins produced by the bacterium C. difficile, Toxin A (TcdA) and Toxin B (TcdB). Certain strains produce an additional toxin, the C. difficile transferase (CDT), which further enhances the virulence and pathogenicity of C. difficile. These toxins disrupt colonic epithelial barrier integrity, and induce inflammation and cellular damage, leading to CDI symptoms. Significant progress has been made in the past decade in elucidating the molecular mechanisms of TcdA, TcdB, and CDT, which provide insights into the management of CDI and the future development of novel treatment strategies based on anti-toxin therapies. While antibiotics are common treatments, high recurrence rates necessitate alternative therapies. Bezlotoxumab, targeting TcdB, is the only available anti-toxin, yet limitations persist, prompting ongoing research. This review highlights the current knowledge of the structure and mechanism of action of C. difficile toxins and their role in disease. By comprehensively describing the toxin-mediated mechanisms, this review provides insights for the future development of novel treatment strategies and the management of CDI.
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Affiliation(s)
- Evdokia Pourliotopoulou
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
| | | | - Melania Kachrimanidou
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
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2
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Tkachenko A. Apoptosis and eryptosis: similarities and differences. Apoptosis 2024; 29:482-502. [PMID: 38036865 DOI: 10.1007/s10495-023-01915-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2023] [Indexed: 12/02/2023]
Abstract
Eryptosis is a regulated cell death (RCD) of mature erythrocytes initially described as a counterpart of apoptosis for enucleated cells. However, over the recent years, a growing number of studies have emphasized certain differences between both cell death modalities. In this review paper, we underline the hallmarks of eryptosis and apoptosis and highlight resemblances and dissimilarities between both RCDs. We summarize and critically discuss differences in the impact of caspase-3, Ca2+ signaling, ROS signaling pathways, opposing roles of casein kinase 1α, protein kinase C, Janus kinase 3, cyclin-dependent kinase 4, and AMP-activated protein kinase to highlight a certain degree of divergence between apoptosis and eryptosis. This review emphasizes the crucial importance of further studies that focus on deepening our knowledge of cell death machinery and identifying novel differences between cell death of nucleated and enucleated cells. This might provide evidence that erythrocytes can be defined as viable entities capable of programmed cell destruction. Additionally, the revealed cell type-specific patterns in cell death can facilitate the development of cell death-modulating therapeutic agents.
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Affiliation(s)
- Anton Tkachenko
- 1st Faculty of Medicine, BIOCEV, Charles University, Průmyslová 595, 25250, Vestec, Czech Republic.
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3
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Punessen NC, Pena C, Sandberg A, Koza LA, Linseman DA. A novel anti-apoptotic role for Cdc42/ACK-1 signaling in neurons. Mol Cell Neurosci 2023; 126:103865. [PMID: 37263460 DOI: 10.1016/j.mcn.2023.103865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/15/2023] [Accepted: 05/25/2023] [Indexed: 06/03/2023] Open
Abstract
Neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's and Parkinson's disease are caused by a progressive and aberrant destruction of neurons in the brain and spinal cord. These disorders lack effective long-term treatments that impact the underlying mechanisms of pathogenesis and as a result, existing options focus primarily on alleviating symptomology. Dysregulated programmed cell death (i.e., apoptosis) is a significant contributor to neurodegeneration, and is controlled by a number of different factors. Rho family GTPases are molecular switches with recognized importance in proper neuronal development and migration that have more recently emerged as central regulators of apoptosis and neuronal survival. Here, we investigated a role for the Rho GTPase family member, Cdc42, and its downstream effectors, in neuronal survival and apoptosis. We initially induced apoptosis in primary cultures of rat cerebellar granule neurons (CGNs) by removing both growth factor-containing serum and depolarizing potassium from the cell medium. We then utilized both chemical inhibitors and adenoviral shRNA targeted to Cdc42 to block the function of Cdc42 or its downstream effectors under either control or apoptotic conditions. Our in vitro studies demonstrate that functional inhibition of Cdc42 or its downstream effector, activated Cdc42-associated tyrosine kinase-1 (ACK-1), had no adverse effects on CGN survival under control conditions, but significantly sensitized neurons to cell death under apoptotic conditions. In conclusion, our results suggest a key pro-survival role for Cdc42/ACK-1 signaling in neurons, particularly in regulating neuronal susceptibility to pro-apoptotic stress such as that observed in neurodegenerative disorders.
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Affiliation(s)
- Noelle C Punessen
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Claudia Pena
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Alexandra Sandberg
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Lilia A Koza
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Daniel A Linseman
- Department of Biological Sciences, University of Denver, Denver, CO, USA; Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, USA.
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4
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Zhang J, Hu T, Wang Y, Zhang X, Zhang H, Lin J, Tang X, Liu X, Chen M, Khan NU, Shen L, Luo P. Investigating the Neurotoxic Impacts of Arsenic and the Neuroprotective Effects of Dictyophora Polysaccharide Using SWATH-MS-Based Proteomics. Molecules 2022; 27:1495. [PMID: 35268596 PMCID: PMC8911851 DOI: 10.3390/molecules27051495] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 11/16/2022] Open
Abstract
Arsenic (As) is one of the most important toxic elements in the natural environment. Currently, although the assessment of the potential health risks of chronic arsenic poisoning has received great attention, the research on the effects of arsenic on the brain is still limited. It has been reported that dictyophora polysaccharide (DIP), a common bioactive natural compound found in dietary plants, could reduce arsenic toxicity. Following behavioral research, comparative proteomics was performed to explore the molecular mechanism of arsenic toxicity to the hippocampi of SD (Sprague Dawley) rats and the protective effect of DIP. The results showed that exposure to arsenic impaired the spatial learning and memory ability of SD rats, while DIP treatment improved both the arsenic-exposed rats. Proteomic analysis showed that arsenic exposure dysregulated the expression of energy metabolism, apoptosis, synapse, neuron, and mitochondria related proteins in the hippocampi of arsenic-exposed rats. However, DIP treatment reversed or restored the expression levels of these proteins, thereby improving the spatial learning and memory ability of arsenic-exposed rats. This study is the first to use high-throughput proteomics to reveal the mechanism of arsenic neurotoxicity in rats as well as the protective mechanism of DIP against arsenic neurotoxicity.
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Affiliation(s)
- Jun Zhang
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, School of Public Health, Ministry of Education, Guizhou Medical University, Guiyang 550025, China; (J.Z.); (T.H.); (Y.W.); (X.Z.)
| | - Ting Hu
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, School of Public Health, Ministry of Education, Guizhou Medical University, Guiyang 550025, China; (J.Z.); (T.H.); (Y.W.); (X.Z.)
| | - Yi Wang
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, School of Public Health, Ministry of Education, Guizhou Medical University, Guiyang 550025, China; (J.Z.); (T.H.); (Y.W.); (X.Z.)
| | - Xinglai Zhang
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, School of Public Health, Ministry of Education, Guizhou Medical University, Guiyang 550025, China; (J.Z.); (T.H.); (Y.W.); (X.Z.)
| | - Huajie Zhang
- College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, China; (H.Z.); (J.L.); (X.T.); (X.L.); (N.U.K.)
| | - Jing Lin
- College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, China; (H.Z.); (J.L.); (X.T.); (X.L.); (N.U.K.)
| | - Xiaoxiao Tang
- College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, China; (H.Z.); (J.L.); (X.T.); (X.L.); (N.U.K.)
| | - Xukun Liu
- College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, China; (H.Z.); (J.L.); (X.T.); (X.L.); (N.U.K.)
| | - Margy Chen
- Department of Psychology, Emory University, Atlanta, GA 30322, USA;
| | - Naseer Ullah Khan
- College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, China; (H.Z.); (J.L.); (X.T.); (X.L.); (N.U.K.)
| | - Liming Shen
- College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, China; (H.Z.); (J.L.); (X.T.); (X.L.); (N.U.K.)
| | - Peng Luo
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, School of Public Health, Ministry of Education, Guizhou Medical University, Guiyang 550025, China; (J.Z.); (T.H.); (Y.W.); (X.Z.)
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5
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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6
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Solabre Valois L, Shi V(H, Bishop P, Zhu B, Nakamura Y, Wilkinson KA, Henley JM. Neurotrophic effects of Botulinum neurotoxin type A in hippocampal neurons involve activation of Rac1 by the non-catalytic heavy chain (HC C/A). IBRO Neurosci Rep 2021; 10:196-207. [PMID: 34041508 PMCID: PMC8143998 DOI: 10.1016/j.ibneur.2021.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/22/2021] [Indexed: 12/19/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are extremely potent naturally occurring poisons that act by silencing neurotransmission. Intriguingly, in addition to preventing presynaptic vesicle fusion, BoNT serotype A (BoNT/A) can also promote axonal regeneration in preclinical models. Here we report that the non-toxic C-terminal region of the receptor-binding domain of heavy chain BoNT/A (HCC/A) activates the small GTPase Rac1 and ERK pathway to potentiate axonal outgrowth, dendritic protrusion formation and synaptic vesicle release in hippocampal neurons. These data are consistent with HCC/A exerting neurotrophic properties, at least in part, independent of any BoNT catalytic activity or toxic effect.
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Affiliation(s)
- Luis Solabre Valois
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Vanilla (Hua) Shi
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Paul Bishop
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Bangfu Zhu
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Yasuko Nakamura
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Kevin A. Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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7
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Matsuoka Y, Al-Shareef H, Kogo M, Nakahara H. Effects of decreased Rac activity and malignant state on oral squamous cell carcinoma in vitro. PLoS One 2021; 16:e0212323. [PMID: 33444335 PMCID: PMC7808617 DOI: 10.1371/journal.pone.0212323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 08/16/2019] [Indexed: 11/19/2022] Open
Abstract
Rac proteins, members of the Rho family of small GTP-binding proteins, have been implicated in transducing a number of signals for various biological mechanisms, including cell cytoskeleton organization, transcription, proliferation, migration, and cancer cell motility. Among human cancers, Rac proteins are highly activated by either overexpression of the genes, up-regulation of the protein, or by mutations that allow the protein to elude normal regulatory signaling pathways. Rac proteins are involved in controlling cell survival and apoptosis. The effects of Rac inhibition by the Rac-specific small molecule inhibitor NSC23766 or by transfection of dominant negative Rac (Rac-DN) were examined on three human-derived oral squamous cell carcinoma cell lines that exhibit different malignancy grades, OSC-20 (grade 3), OSC-19 (grade 4C), and HOC313 (grade 4D). Upon suppression of Rac, OSC-19 and HOC313 cells showed significant decreases in Rac activity and resulted in condensation of the nuclei and up-regulation of c-Jun N-terminal kinase (JNK), leading to caspase-dependent apoptosis. In contrast, OSC-20 cells showed only a slight decrease in Rac activity, which resulted in slight activation of JNK and no change in the nuclei. Fibroblasts treated with NSC23766 also showed only a slight decrease in Rac activity with no change in the nuclei or JNK activity. Our results indicated that apoptosis elicited by the inhibition of Rac depended on the extent of decreased Rac activity and the malignant state of the squamous cell carcinoma. In addition, activation of JNK strongly correlated with apoptosis. Rac inhibition may represent a novel therapeutic approach for cancer treatment.
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Affiliation(s)
- Yudai Matsuoka
- The First Department of Oral & Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Hani Al-Shareef
- Department of Oral & Maxillofacial Surgery, Osaka City University Graduate School of Medicine, Osaka, Osaka, Japan
| | - Mikihiko Kogo
- The First Department of Oral & Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Hirokazu Nakahara
- The First Department of Oral & Maxillofacial Surgery, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
- Department of Oral & Maxillofacial Surgery, Osaka City University Graduate School of Medicine, Osaka, Osaka, Japan
- * E-mail:
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8
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Maltas J, Reed H, Porter A, Malliri A. Mechanisms and consequences of dysregulation of the Tiam family of Rac activators in disease. Biochem Soc Trans 2020; 48:2703-2719. [PMID: 33200195 DOI: 10.1042/bst20200481] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 12/14/2022]
Abstract
The Tiam family proteins - Tiam1 and Tiam2/STEF - are Rac1-specific Guanine Nucleotide Exchange Factors (GEFs) with important functions in epithelial, neuronal, immune and other cell types. Tiam GEFs regulate cellular migration, proliferation and survival, mainly through activating and directing Rac1 signalling. Dysregulation of the Tiam GEFs is significantly associated with human diseases including cancer, immunological and neurological disorders. Uncovering the mechanisms and consequences of dysregulation is therefore imperative to improving the diagnosis and treatment of diseases. Here we compare and contrast the subcellular localisation and function of Tiam1 and Tiam2/STEF, and review the evidence for their dysregulation in disease.
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Affiliation(s)
- Joe Maltas
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Hannah Reed
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Andrew Porter
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Angeliki Malliri
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
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9
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Stankiewicz TR, Pena C, Bouchard RJ, Linseman DA. Dysregulation of Rac or Rho elicits death of motor neurons and activation of these GTPases is altered in the G93A mutant hSOD1 mouse model of amyotrophic lateral sclerosis. Neurobiol Dis 2020; 136:104743. [PMID: 31931138 DOI: 10.1016/j.nbd.2020.104743] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/18/2019] [Accepted: 01/08/2020] [Indexed: 12/11/2022] Open
Abstract
Rho GTPases play a central role in neuronal survival; however, the antagonistic relationship between Rac and Rho in the regulation of motor neuron survival remains poorly defined. In the current study, we demonstrate that treatment with NSC23766, a selective inhibitor of the Rac-specific guanine nucleotide exchange factors, Tiam1 and Trio, is sufficient to induce the death of embryonic stem cell (ESC)-derived motor neurons. The mode of cell death is primarily apoptotic and is characterized by caspase-3 activation, de-phosphorylation of ERK5 and AKT, and nuclear translocation of the BH3-only protein Bad. As opposed to the inhibition of Rac, motor neuron cell death is also induced by constitutive activation of Rho, via a mechanism that depends on Rho kinase (ROCK) activity. Investigation of Rac and Rho in the G93A mutant, human Cu, Zn-superoxide dismutase (hSOD1) mouse model of amyotrophic lateral sclerosis (ALS), revealed that active Rac1-GTP is markedly decreased in spinal cord motor neurons of transgenic mice at disease onset and end-stage, when compared to age-matched wild type (WT) littermates. Furthermore, although there is no significant change in active RhoA-GTP, total RhoB displays a striking redistribution from motor neuron nuclei in WT mouse spinal cord to motor neuron axons in end-stage G93A mutant hSOD1 mice. Collectively, these data suggest that the intricate balance between pro-survival Rac signaling and pro-apoptotic Rho/ROCK signaling is critical for motor neuron survival and therefore, disruption in the balance of their activities and/or localization may contribute to the death of motor neurons in ALS.
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Affiliation(s)
- Trisha R Stankiewicz
- University of Denver, Department of Biological Sciences, Denver, CO 80208, United States
| | - Claudia Pena
- University of Denver, Department of Biological Sciences, Denver, CO 80208, United States
| | - Ron J Bouchard
- Research Service, Veterans Affairs Medical Center, Denver, CO, 80220, United States
| | - Daniel A Linseman
- University of Denver, Department of Biological Sciences, Eleanor Roosevelt Institute, and Knoebel Institute for Healthy Aging, 2155 E. Wesley Ave., Denver, CO, 80208, United States.
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10
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Mikdache A, Fontenas L, Albadri S, Revenu C, Loisel-Duwattez J, Lesport E, Degerny C, Del Bene F, Tawk M. Elmo1 function, linked to Rac1 activity, regulates peripheral neuronal numbers and myelination in zebrafish. Cell Mol Life Sci 2020; 77:161-177. [PMID: 31161284 PMCID: PMC11104998 DOI: 10.1007/s00018-019-03167-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Abstract
Peripheral nervous system development involves a tight coordination of neuronal birth and death and a substantial remodelling of the myelinating glia cytoskeleton to achieve myelin wrapping of its projecting axons. However, how these processes are coordinated through time is still not understood. We have identified engulfment and cell motility 1, Elmo1, as a novel component that regulates (i) neuronal numbers within the Posterior Lateral Line ganglion and (ii) radial sorting of axons by Schwann cells (SC) and myelination in the PLL system in zebrafish. Our results show that neuronal and myelination defects observed in elmo1 mutant are rescued through small GTPase Rac1 activation. Inhibiting macrophage development leads to a decrease in neuronal numbers, while peripheral myelination is intact. However, elmo1 mutants do not show defective macrophage activity, suggesting a role for Elmo1 in PLLg neuronal development and SC myelination independent of macrophages. Forcing early Elmo1 and Rac1 expression specifically within SCs rescues elmo1-/- myelination defects, highlighting an autonomous role for Elmo1 and Rac1 in radial sorting of axons by SCs and myelination. This uncovers a previously unknown function of Elmo1 that regulates fundamental aspects of PNS development.
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Affiliation(s)
- Aya Mikdache
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Laura Fontenas
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
- Department of Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA
| | - Shahad Albadri
- Institut Curie, PSL Research University, 75005, Paris, France
| | - Celine Revenu
- Institut Curie, PSL Research University, 75005, Paris, France
| | - Julien Loisel-Duwattez
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Emilie Lesport
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Cindy Degerny
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | | | - Marcel Tawk
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France.
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11
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ARHGAP17 suppresses tumor progression and up-regulates P21 and P27 expression via inhibiting PI3K/AKT signaling pathway in cervical cancer. Gene 2019; 692:9-16. [DOI: 10.1016/j.gene.2019.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/29/2018] [Accepted: 01/02/2019] [Indexed: 11/21/2022]
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12
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Connexin 43 Loss Triggers Cell Cycle Entry and Invasion in Non-Neoplastic Breast Epithelium: A Role for Noncanonical Wnt Signaling. Cancers (Basel) 2019; 11:cancers11030339. [PMID: 30857262 PMCID: PMC6468895 DOI: 10.3390/cancers11030339] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/15/2019] [Accepted: 03/04/2019] [Indexed: 12/26/2022] Open
Abstract
(1) Background: The expression of connexin 43 (Cx43) is disrupted in breast cancer, and re-expression of this protein in human breast cancer cell lines leads to decreased proliferation and invasiveness, suggesting a tumor suppressive role. This study aims to investigate the role of Cx43 in proliferation and invasion starting from non-neoplastic breast epithelium. (2) Methods: Nontumorigenic human mammary epithelial HMT-3522 S1 cells and Cx43 shRNA-transfected counterparts were cultured under 2-dimensional (2-D) and 3-D conditions. (3) Results: Silencing Cx43 induced mislocalization of β-catenin and Scrib from apicolateral membrane domains in glandular structures or acini formed in 3-D culture, suggesting the loss of apical polarity. Cell cycle entry and proliferation were enhanced, concomitantly with c-Myc and cyclin D1 upregulation, while no detectable activation of Wnt/β-catenin signaling was observed. Motility and invasion were also triggered and were associated with altered acinar morphology and activation of ERK1/2 and Rho GTPase signaling, which acts downstream of the noncanonical Wnt pathway. The invasion of Cx43-shRNA S1 cells was observed only under permissive stiffness of the extracellular matrix (ECM). (4) Conclusion: Our results suggest that Cx43 controls proliferation and invasion in the normal mammary epithelium in part by regulating noncanonical Wnt signaling.
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13
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Carvalho BC, Oliveira LC, Rocha CD, Fernandes HB, Oliveira IM, Leão FB, Valverde TM, Rego IMG, Ghosh S, Silva AM. Both knock-down and overexpression of Rap2a small GTPase in macrophages result in impairment of NF-κB activity and inflammatory gene expression. Mol Immunol 2019; 109:27-37. [PMID: 30851634 DOI: 10.1016/j.molimm.2019.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 01/12/2019] [Accepted: 02/17/2019] [Indexed: 02/08/2023]
Abstract
Small Ras GTPases are key molecules that regulate a variety of cellular responses in different cell types. Rap1 plays important functions in the regulation of macrophage biology during inflammation triggered by toll-like receptors (TLRs). However, despite sharing a relatively high degree of similarity with Rap1, no studies concerning Rap2 in macrophages and innate immunity have been reported yet. In this work, we show that either way alterations in the levels of Rap2a hampers proper macrophages response to TLR stimulation. Rap2a is activated by LPS in macrophages, and although putative activator TLR-inducible Ras guanine exchange factor RasGEF1b was sufficient to induce, it was not fully required for Rap2a activation. Silencing of Rap2a impaired LPS-induced production of IL-6 cytokine and KC/Cxcl1 chemokine, and also NF-κB activity as measured by reporter gene studies. Surprisingly, overexpression of Rap2a did also lead to marked inhibition of NF-κB activation induced by LPS, Pam3CSK4 and downstream TLR signaling molecules. We also found that Rap2a can inhibit the LPS-induced phosphorylation of the NF-κB subunit p65 at serine 536. Collectively, our data suggest that expression levels of Rap2a in macrophages might be tightly regulated to avoid unbalanced immune response. Our results implicate Rap2a in TLR-mediated responses by contributing to balanced NF-κB activity status in macrophages.
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Affiliation(s)
- Brener C Carvalho
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Leonardo C Oliveira
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Carolina D Rocha
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Heliana B Fernandes
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Isadora M Oliveira
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Felipe B Leão
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Thalita M Valverde
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Igor M G Rego
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Sankar Ghosh
- Department of Microbiology & Immunology, College of Physicians & Surgeons, Columbia University, New York, NY, USA
| | - Aristóbolo M Silva
- Laboratory of Inflammatory Genes, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
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14
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Taram F, Ignowski E, Duval N, Linseman DA. Neuroprotection Comparison of Rosmarinic Acid and Carnosic Acid in Primary Cultures of Cerebellar Granule Neurons. Molecules 2018; 23:E2956. [PMID: 30428519 PMCID: PMC6278428 DOI: 10.3390/molecules23112956] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/01/2018] [Accepted: 11/07/2018] [Indexed: 12/16/2022] Open
Abstract
Neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS), Alzheimer's disease, and Parkinson's disease, are characterized by the progressive loss of neurons in specific regions of the brain and/or spinal cord. Neuronal cell loss typically occurs by either apoptotic or necrotic mechanisms. Oxidative stress and nitrosative stress, along with excitotoxicity and caspase activation, have all been implicated as major underlying causes of neuronal cell death. Diverse nutraceuticals (bioactive compounds found in common foods) have been shown to have neuroprotective effects in a variety of in vitro and in vivo disease models. In the current study, we compared the neuroprotective effects of two polyphenolic compounds, rosmarinic acid and carnosic acid, which are both found at substantial concentrations in the herb rosemary. The capacity of these compounds to rescue primary cultures of rat cerebellar granule neurons (CGNs) from a variety of stressors was investigated. Both polyphenols significantly reduced CGN death induced by the nitric oxide donor, sodium nitroprusside (nitrosative stress). Rosmarinic acid uniquely protected CGNs from glutamate-induced excitotoxicity, while only carnosic acid rescued CGNs from caspase-dependent apoptosis induced by removal of depolarizing extracellular potassium (5K apoptotic condition). Finally, we found that carnosic acid protects CGNs from 5K-induced apoptosis by activating a phosphatidylinositol 3-kinase (PI3K) pro-survival pathway. The shared and unique neuroprotective effects of these two compounds against diverse modes of neuronal cell death suggest that future preclinical studies should explore the potential complementary effects of these rosemary polyphenols on neurodegenerative disease progression.
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Affiliation(s)
- Faten Taram
- Department of Biological Sciences, University of Denver, 2199 S. University Blvd., Denver, CO 80208, USA.
| | - Elizabeth Ignowski
- Department of Biological Sciences, University of Denver, 2199 S. University Blvd., Denver, CO 80208, USA.
| | - Nathan Duval
- Knoebel Institute for Healthy Aging, University of Denver, 2155 E. Wesley Ave., Denver, CO 80208, USA.
| | - Daniel A Linseman
- Department of Biological Sciences, University of Denver, 2199 S. University Blvd., Denver, CO 80208, USA.
- Knoebel Institute for Healthy Aging, University of Denver, 2155 E. Wesley Ave., Denver, CO 80208, USA.
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15
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Cai CY, Wu HY, Luo CX, Zhu DY, Zhang Y, Zhou QG, Zhang J. Extracellular regulated protein kinaseis critical for the role of 5-HT1a receptor in modulating nNOS expression and anxiety-related behaviors. Behav Brain Res 2017; 357-358:88-97. [PMID: 29246772 DOI: 10.1016/j.bbr.2017.12.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 08/04/2017] [Accepted: 12/11/2017] [Indexed: 12/20/2022]
Abstract
Our previous study found that serotonin 1A receptor (5-HT1aR) is an endogenous suppressor of nNOS expression in the hippocampus, which accounts for anxiolytic effect of fluoxetine. However, the precise molecular mechanism remains unknown. By using 8-OH-DPAT, a selective 5-HT1aR agonist, NAN-190, a selective 5-HT1aR antagonist, and U0126, an Extracellular Regulated Protein Kinases (ERK) phosphorylation inhibitor, we investigated the role of ERK in 5-HT1aR-nNOS pathway. Western blots analysis demonstrated that 5-HT1aR activation up-regulated the level of phosphorylated ERK (P-ERK) beginning at 5 min and down-regulated the expression of nNOS beginning at 20 min. Meanwhile, blockage of 5-HT1aR resulted in a decrease in P-ERK beginning at 20 min and caused an increase in nNOS expression beginning at 6 h. Although U0126 itself did not alter nNOS expression and activity, NO level, and anxiety-related behaviors, the treatment totally reversed 8-OH-DPAT-induced reduction in nNOS expression and function, and anxiolytic effect. Besides, our data showed that ERK phosphorylation was essential for 5-HT1aR activation-induced cAMP responsive element binding protein (CREB) phosphorylation, hippocampal neurogenesis and synaptogenesis of newborn neuron. Our study suggests a crucial role of ERK phosphorylation in the regulation of nNOS expression by 5-HT1aR, which is helpful for understanding the mechanism of 5-HT1aR-based anxiolytic treatment.
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Affiliation(s)
- Cheng-Yun Cai
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China
| | - Hai-Yin Wu
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China
| | - Chun-Xia Luo
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China
| | - Dong-Ya Zhu
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China; The Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing, 211166, People's Republic of China
| | - Yu Zhang
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China.
| | - Qi-Gang Zhou
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China.
| | - Jing Zhang
- Institution of Stem Cells and Neuroregeneration, Nanjing Medical University, Nanjing, 211166, People's Republic of China; Departments of Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing, 211166, People's Republic of China.
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16
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Nakamura T, Ueyama T, Ninoyu Y, Sakaguchi H, Choijookhuu N, Hishikawa Y, Kiyonari H, Kohta M, Sakahara M, de Curtis I, Kohmura E, Hisa Y, Aiba A, Saito N. Novel role of Rac-Mid1 signaling in medial cerebellar development. Development 2017; 144:1863-1875. [PMID: 28512198 DOI: 10.1242/dev.147900] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/31/2017] [Indexed: 02/04/2023]
Abstract
Rac signaling impacts a relatively large number of downstream targets; however, few studies have established an association between Rac pathways and pathological conditions. In the present study, we generated mice with double knockout of Rac1 and Rac3 (Atoh1-Cre;Rac1flox/flox;Rac3-/- ) in cerebellar granule neurons (CGNs). We observed impaired tangential migration at E16.5, as well as numerous apoptotic CGNs at the deepest layer of the external granule layer (EGL) in the medial cerebellum of Atoh1-Cre;Rac1flox/flox;Rac3-/- mice at P8. Atoh1-Cre;Rac1flox/flox;Rac3-/- CGNs differentiated normally until expression of p27kip1 and NeuN in the deep EGL at P5. Primary CGNs and cerebellar microexplants from Atoh1-Cre;Rac1flox/flox;Rac3-/- mice exhibited impaired neuritogenesis, which was more apparent in Map2-positive dendrites. Such findings suggest that impaired tangential migration and final differentiation of CGNs have resulted in decreased cerebellum size and agenesis of the medial internal granule layer, respectively. Furthermore, Rac depleted/deleted cells exhibited decreased levels of Mid1 and impaired mTORC1 signaling. Mid1 depletion in CGNs produced mild impairments in neuritogenesis and reductions in mTORC1 signaling. Thus, a novel Rac-signaling pathway (Rac1-Mid1-mTORC1) may be involved in medial cerebellar development.
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Affiliation(s)
- Takashi Nakamura
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan.,Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Takehiko Ueyama
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Yuzuru Ninoyu
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Hirofumi Sakaguchi
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Narantsog Choijookhuu
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Yoshitaka Hishikawa
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Hiroshi Kiyonari
- Animal Resource Development Unit and Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe 650-0047, Japan
| | - Masaaki Kohta
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Mizuho Sakahara
- Department of Molecular Genetics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Ivan de Curtis
- Division of Neuroscience, San Raffaele Scientific Institute, Milano 20132, Italy
| | - Eiji Kohmura
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Yasuo Hisa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Atsu Aiba
- Department of Molecular Genetics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.,Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
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17
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Abstract
Clostridium difficile is the cause of antibiotics-associated diarrhea and pseudomembranous colitis. The pathogen produces three protein toxins: C. difficile toxins A (TcdA) and B (TcdB), and C. difficile transferase toxin (CDT). The single-chain toxins TcdA and TcdB are the main virulence factors. They bind to cell membrane receptors and are internalized. The N-terminal glucosyltransferase and autoprotease domains of the toxins translocate from low-pH endosomes into the cytosol. After activation by inositol hexakisphosphate (InsP6), the autoprotease cleaves and releases the glucosyltransferase domain into the cytosol, where GTP-binding proteins of the Rho/Ras family are mono-O-glucosylated and, thereby, inactivated. Inactivation of Rho proteins disturbs the organization of the cytoskeleton and affects multiple Rho-dependent cellular processes, including loss of epithelial barrier functions, induction of apoptosis, and inflammation. CDT, the third C. difficile toxin, is a binary actin-ADP-ribosylating toxin that causes depolymerization of actin, thereby inducing formation of the microtubule-based protrusions. Recent progress in understanding of the toxins' actions include insights into the toxin structures, their interaction with host cells, and functional consequences of their actions.
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Affiliation(s)
- Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| | - Carsten Schwan
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
| | - Thomas Jank
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, 79104 Freiburg, Germany; , ,
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18
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Fettucciari K, Ponsini P, Gioè D, Macchioni L, Palumbo C, Antonelli E, Coaccioli S, Villanacci V, Corazzi L, Marconi P, Bassotti G. Enteric glial cells are susceptible to Clostridium difficile toxin B. Cell Mol Life Sci 2017; 74:1527-1551. [PMID: 27891552 PMCID: PMC11107567 DOI: 10.1007/s00018-016-2426-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/27/2016] [Accepted: 11/21/2016] [Indexed: 02/06/2023]
Abstract
Clostridium difficile causes nosocomial/antibiotic-associated diarrhoea and pseudomembranous colitis. The major virulence factors are toxin A and toxin B (TcdB), which inactivate GTPases by monoglucosylation, leading to cytopathic (cytoskeleton alteration, cell rounding) and cytotoxic effects (cell-cycle arrest, apoptosis). C. difficile toxins breaching the intestinal epithelial barrier can act on underlying cells, enterocytes, colonocytes, and enteric neurons, as described in vitro and in vivo, but until now no data have been available on enteric glial cell (EGC) susceptibility. EGCs are crucial for regulating the enteric nervous system, gut homeostasis, the immune and inflammatory responses, and digestive and extradigestive diseases. Therefore, we evaluated the effects of C. difficile TcdB in EGCs. Rat-transformed EGCs were treated with TcdB at 0.1-10 ng/ml for 1.5-48 h, and several parameters were analysed. TcdB induces the following in EGCs: (1) early cell rounding with Rac1 glucosylation; (2) early G2/M cell-cycle arrest by cyclin B1/Cdc2 complex inactivation caused by p27 upregulation, the downregulation of cyclin B1 and Cdc2 phosphorylated at Thr161 and Tyr15; and (3) apoptosis by a caspase-dependent but mitochondria-independent pathway. Most importantly, the stimulation of EGCs with TNF-α plus IFN-γ before, concomitantly or after TcdB treatment strongly increased TcdB-induced apoptosis. Furthermore, EGCs that survived the cytotoxic effect of TcdB did not recover completely and showed not only persistent Rac1 glucosylation, cell-cycle arrest and low apoptosis but also increased production of glial cell-derived neurotrophic factor, suggesting self-rescuing mechanisms. In conclusion, the high susceptibility of EGCs to TcdB in vitro, the increased sensitivity to inflammatory cytokines related to apoptosis and the persistence of altered functions in surviving cells suggest an important in vivo role of EGCs in the pathogenesis of C. difficile infection.
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Affiliation(s)
- Katia Fettucciari
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy.
| | - Pamela Ponsini
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy
| | - Davide Gioè
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy
| | - Lara Macchioni
- Department of Experimental Medicine, Physiology and Biochemistry Section, Perugia University, Perugia, Italy
| | - Camilla Palumbo
- Department of Clinical Sciences and Translational Medicine, Tor Vergata University, Rome, Italy
| | | | - Stefano Coaccioli
- Department of Medicine, Internal Medicine, Rheumatology and Medical Therapy of Pain Section, Perugia University, District of Terni, Perugia, Italy
| | | | - Lanfranco Corazzi
- Department of Experimental Medicine, Physiology and Biochemistry Section, Perugia University, Perugia, Italy
| | - Pierfrancesco Marconi
- Department of Experimental Medicine, Histology and Medical Embryology Section, Perugia University, Piazza Lucio Severi 1, Edificio B IV piano, Sant'Andrea delle Fratte, 06132, Perugia, Italy
| | - Gabrio Bassotti
- Department of Medicine, Gastroenterology, Hepatology and Digestive Endoscopy Section, Perugia University, Perugia, Italy
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19
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Deshmukh J, Pofahl R, Haase I. Epidermal Rac1 regulates the DNA damage response and protects from UV-light-induced keratinocyte apoptosis and skin carcinogenesis. Cell Death Dis 2017; 8:e2664. [PMID: 28277539 PMCID: PMC5386559 DOI: 10.1038/cddis.2017.63] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/31/2016] [Accepted: 01/09/2017] [Indexed: 12/13/2022]
Abstract
Non-melanoma skin cancer (NMSC) is the most common type of cancer. Increased expression and activity of Rac1, a small Rho GTPase, has been shown previously in NMSC and other human cancers; suggesting that Rac1 may function as an oncogene in skin. DMBA/TPA skin carcinogenesis studies in mice have shown that Rac1 is required for chemically induced skin papilloma formation. However, UVB radiation by the sun, which causes DNA damage, is the most relevant cause for NMSC. A potential role of Rac1 in UV-light-induced skin carcinogenesis has not been investigated so far. To investigate this, we irradiated mice with epidermal Rac1 deficiency (Rac1-EKO) and their controls using a well-established protocol for long-term UV-irradiation. Most of the Rac1-EKO mice developed severe skin erosions upon long-term UV-irradiation, unlike their controls. These skin erosions in Rac1-EKO mice healed subsequently. Surprisingly, we observed development of squamous cell carcinomas (SCCs) within the UV-irradiation fields. This shows that the presence of Rac1 in the epidermis protects from UV-light-induced skin carcinogenesis. Short-term UV-irradiation experiments revealed increased UV-light-induced apoptosis of Rac1-deficient epidermal keratinocytes in vitro as well as in vivo. Further investigations using cyclobutane pyrimidine dimer photolyase transgenic mice revealed that the observed increase in UV-light-induced keratinocyte apoptosis in Rac1-EKO mice is DNA damage dependent and correlates with caspase-8 activation. Furthermore, Rac1-deficient keratinocytes showed reduced levels of p53, γ-H2AX and p-Chk1 suggesting an attenuated DNA damage response upon UV-irradiation. Taken together, our data provide direct evidence for a protective role of Rac1 in UV-light-induced skin carcinogenesis and keratinocyte apoptosis probably through regulating mechanisms of the DNA damage response and repair pathways.
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Affiliation(s)
- Jayesh Deshmukh
- Department of Dermatology, University of Cologne, Kerpener Strasse 62, Cologne 50937, Germany
| | - Ruth Pofahl
- Department of Dermatology, University of Cologne, Kerpener Strasse 62, Cologne 50937, Germany
| | - Ingo Haase
- Department of Dermatology, University of Cologne, Kerpener Strasse 62, Cologne 50937, Germany
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20
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Di Bella S, Ascenzi P, Siarakas S, Petrosillo N, di Masi A. Clostridium difficile Toxins A and B: Insights into Pathogenic Properties and Extraintestinal Effects. Toxins (Basel) 2016; 8:E134. [PMID: 27153087 PMCID: PMC4885049 DOI: 10.3390/toxins8050134] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile infection (CDI) has significant clinical impact especially on the elderly and/or immunocompromised patients. The pathogenicity of Clostridium difficile is mainly mediated by two exotoxins: toxin A (TcdA) and toxin B (TcdB). These toxins primarily disrupt the cytoskeletal structure and the tight junctions of target cells causing cell rounding and ultimately cell death. Detectable C. difficile toxemia is strongly associated with fulminant disease. However, besides the well-known intestinal damage, recent animal and in vitro studies have suggested a more far-reaching role for these toxins activity including cardiac, renal, and neurologic impairment. The creation of C. difficile strains with mutations in the genes encoding toxin A and B indicate that toxin B plays a major role in overall CDI pathogenesis. Novel insights, such as the role of a regulator protein (TcdE) on toxin production and binding interactions between albumin and C. difficile toxins, have recently been discovered and will be described. Our review focuses on the toxin-mediated pathogenic processes of CDI with an emphasis on recent studies.
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Affiliation(s)
- Stefano Di Bella
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome 00149, Italy.
| | - Paolo Ascenzi
- Department of Science, Roma Tre University, Rome 00154, Italy.
| | - Steven Siarakas
- Department of Microbiology and Infectious Diseases, Concord Repatriation General Hospital, Sydney 2139, Australia.
| | - Nicola Petrosillo
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome 00149, Italy.
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21
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Methyl-Arginine Profile of Brain from Aged PINK1-KO+A53T-SNCA Mice Suggests Altered Mitochondrial Biogenesis. PARKINSONS DISEASE 2016; 2016:4686185. [PMID: 27034888 PMCID: PMC4791501 DOI: 10.1155/2016/4686185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 11/29/2022]
Abstract
Hereditary Parkinson's disease can be triggered by an autosomal dominant overdose of alpha-Synuclein (SNCA) or the autosomal recessive deficiency of PINK1. We recently showed that the combination of PINK1-knockout with overexpression of A53T-SNCA in double mutant (DM) mice potentiates phenotypes and reduces survival. Now we studied brain hemispheres of DM mice at age of 18 months in a hypothesis-free approach, employing a quantitative label-free global proteomic mass spectrometry scan of posttranslational modifications focusing on methyl-arginine. The strongest effects were documented for the adhesion modulator CMAS, the mRNA decapping/deadenylation factor PATL1, and the synaptic plasticity mediator CRTC1/TORC1. In addition, an intriguing effect was observed for the splicing factor PSF/SFPQ, known to interact with the dopaminergic differentiation factor NURR1 as well as with DJ-1, the protein responsible for the autosomal recessive PARK7 variant of PD. CRTC1, PSF, and DJ-1 are modulators of PGC1alpha and of mitochondrial biogenesis. This pathway was further stressed by dysregulations of oxygen sensor EGLN3 and of nuclear TMPO. PSF and TMPO cooperate with dopaminergic differentiation factors LMX1B and NURR1. Further dysregulations concerned PRR18, TRIO, HNRNPA1, DMWD, WAVE1, ILDR2, DBNDD1, and NFM. Thus, we report selective novel endogenous stress responses in brain, which highlight early dysregulations of mitochondrial homeostasis and midbrain vulnerability.
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22
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Maino B, D'Agata V, Severini C, Ciotti MT, Calissano P, Copani A, Chang YC, DeLisi C, Cavallaro S. Igf1 and Pacap rescue cerebellar granule neurons from apoptosis via a common transcriptional program. Cell Death Discov 2015; 1. [PMID: 26941962 PMCID: PMC4773033 DOI: 10.1038/cddiscovery.2015.29] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A shift of the delicate balance between apoptosis and survival-inducing signals determines the fate of neurons during the development of the central nervous system and its homeostasis throughout adulthood. Both pathways, promoting or protecting from apoptosis, trigger a transcriptional program. We conducted whole-genome expression profiling to decipher the transcriptional regulatory elements controlling the apoptotic/survival switch in cerebellar granule neurons following the induction of apoptosis by serum and potassium deprivation or their rescue by either insulin-like growth factor-1 (Igf1) or pituitary adenylyl cyclase-activating polypeptide (Pacap). Although depending on different upstream signaling pathways, the survival effects of Igf1 and Pacap converged into common transcriptional cascades, thus suggesting the existence of a general transcriptional program underlying neuronal survival.
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Affiliation(s)
- Barbara Maino
- Institute of Neurological Sciences, Italian National Research Council, 95126 Catania, Italy
| | - Velia D'Agata
- Department of Biomedical and Biotechnological Sciences, Section of Human Anatomy and Histology, University of Catania, 95123 Catania, Italy
| | - Cinzia Severini
- Institute of Neurobiology and Molecular Medicine, Italian National Research Council, 00143 Roma, Italy
| | | | | | - Agata Copani
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy
| | - Yi-Chien Chang
- Center for Advanced Genomic Technology, Boston University, Boston, MA 02215, USA
| | - Charles DeLisi
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sebastiano Cavallaro
- Institute of Neurological Sciences, Italian National Research Council, 95126 Catania, Italy
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