scholarly journals RIPK1-Associated Inborn Errors of Innate Immunity

2021 ◽  
Vol 12 ◽  
Author(s):  
Jiahui Zhang ◽  
Taijie Jin ◽  
Ivona Aksentijevich ◽  
Qing Zhou
Keyword(s):  
Immune Deficiency ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Physiological Role ◽  
Model Organisms ◽  
Loss Of Function ◽  
Inborn Errors ◽  
Post Translational Modifications ◽  
Cell Death Signaling

RIPK1 (receptor-interacting serine/threonine-protein kinase 1) is a key molecule for mediating apoptosis, necroptosis, and inflammatory pathways downstream of death receptors (DRs) and pattern recognition receptors (PRRs). RIPK1 functions are regulated by multiple post-translational modifications (PTMs), including ubiquitination, phosphorylation, and the caspase-8-mediated cleavage. Dysregulation of these modifications leads to an immune deficiency or a hyperinflammatory disease in humans. Over the last decades, numerous studies on the RIPK1 function in model organisms have provided insights into the molecular mechanisms of RIPK1 role in the maintenance of immune homeostasis. However, the physiological role of RIPK1 in the regulation of cell survival and cell death signaling in humans remained elusive. Recently, RIPK1 loss-of-function (LoF) mutations and cleavage-deficient mutations have been identified in humans. This review discusses the molecular pathogenesis of RIPK1-deficiency and cleavage-resistant RIPK1 induced autoinflammatory (CRIA) disorders and summarizes the clinical manifestations of respective diseases to help with the identification of new patients.

scholarly journals Caenorhabditits elegans LRK-1 and PINK-1 Act Antagonistically in Stress Response and Neurite Outgrowth

2009 ◽  
Vol 284 (24) ◽  
pp. 16482-16491 ◽  
Author(s):  
Julia Sämann ◽  
Jan Hegermann ◽  
Erika von Gromoff ◽  
Stefan Eimer ◽  
Ralf Baumeister ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Stress Response ◽  
Parkinson Disease ◽  
Neurite Outgrowth ◽  
Physiological Role ◽  
Model Organisms ◽  
Loss Of Function ◽  
C Elegans ◽  
Genes Encoding

Mutations in two genes encoding the putative kinases LRRK2 and PINK1 have been associated with inherited variants of Parkinson disease. The physiological role of both proteins is not known at present, but studies in model organisms have linked their mutants to distinct aspects of mitochondrial dysfunction, increased vulnerability to oxidative and endoplasmic reticulum stress, and intracellular protein sorting. Here, we show that a mutation in the Caenorhabditits elegans homologue of the PTEN-induced kinase pink-1 gene resulted in reduced mitochondrial cristae length and increased paraquat sensitivity of the nematode. Moreover, the mutants also displayed defects in axonal outgrowth of a pair of canal-associated neurons. We demonstrate that in the absence of lrk-1, the C. elegans homologue of human LRRK2, all phenotypic aspects of pink-1 loss-of-function mutants were suppressed. Conversely, the hypersensitivity of lrk-1 mutant animals to the endoplasmic reticulum stressor tunicamycin was reduced in a pink-1 mutant background. These results provide the first evidence of an antagonistic role of PINK-1 and LRK-1. Due to the similarity of the C. elegans proteins to human LRRK2 and PINK1, we suggest a common role of both factors in cellular functions including stress response and regulation of neurite outgrowth. This study might help to link pink-1/PINK1 and lrk-1/LRRK2 function to the pathological processes resulting from Parkinson disease-related mutants in both genes, the first manifestations of which are cytoskeletal defects in affected neurons.

Structure, Function, Involvement in Diseases and Targeting of 14-3-3 Proteins: An Update

2018 ◽  
Vol 25 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Ylenia Cau ◽  
Daniela Valensin ◽  
Mattia Mori ◽  
Sara Draghi ◽  
Maurizio Botta
Keyword(s):  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Specific Protein ◽  
Protein Protein Interactions ◽  
Cellular Processes ◽  
Protein Partners ◽  
High Sequence Homology ◽  
Small Molecule Modulators

14-3-3 is a class of proteins able to interact with a multitude of targets by establishing protein-protein interactions (PPIs). They are usually found in all eukaryotes with a conserved secondary structure and high sequence homology among species. 14-3-3 proteins are involved in many physiological and pathological cellular processes either by triggering or interfering with the activity of specific protein partners. In the last years, the scientific community has collected many evidences on the role played by seven human 14-3-3 isoforms in cancer or neurodegenerative diseases. Indeed, these proteins regulate the molecular mechanisms associated to these diseases by interacting with (i) oncogenic and (ii) pro-apoptotic proteins and (iii) with proteins involved in Parkinson and Alzheimer diseases. The discovery of small molecule modulators of 14-3-3 PPIs could facilitate complete understanding of the physiological role of these proteins, and might offer valuable therapeutic approaches for these critical pathological states.

The role of PCSK9 in infectious diseases.

2021 ◽  
Vol 28 ◽  
Author(s):  
Laura Magnasco ◽  
Chiara Sepulcri ◽  
Roberta Maria Antonello ◽  
Stefano Di Bella ◽  
Laura Labate ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Malaria Infection ◽  
Bacterial Infections ◽  
Viral Infections ◽  
Physiological Role ◽  
Protective Role ◽  
Loss Of Function ◽  
Pcsk9 Inhibition ◽  
Sepsis And Septic Shock

Background: In recent years, many aspects of the physiological role of PCSK9 have been elucidated, particularly regarding its role in lipid metabolism, cardiovascular risk, and its role in innate immunity. Increasing evidence is available about the involvement of PCSK9 in the pathogenesis of viral infections, mainly HCV, and the regulation of host response to bacterial infections, primarily sepsis and septic shock. Moreover, the action of PCSK9 has been investigated as a crucial step in the pathogenesis of malaria infection and disease severity. Objective: This paper aims to review the available published literature on the role of PCSK9 in a wide array of infectious diseases. Conclusion: Besides the ongoing investigation on PCSK9 inhibition among HIV-infected patients to treat HIV- and ART-related hyperlipidemia, preclinical studies indicate how PCSK9 is involved in reducing the replication of HCV. Interestingly, high plasmatic PCSK9 levels have been described in patients with sepsis. Moreover, a protective role of PCSK9 inhibition has also been proposed against dengue and SARS-CoV-2 viral infections. Finally, a loss of function in the PCSK9-encoding gene has been reported to reduce malaria infection mortality.

scholarly journals Neuroinflammation and Its Impact on the Pathogenesis of COVID-19

2021 ◽  
Vol 8 ◽  
Author(s):  
Mohammed M. Almutairi ◽  
Farzane Sivandzade ◽  
Thamer H. Albekairi ◽  
Faleh Alqahtani ◽  
Luca Cucullo
Keyword(s):  
Immune System ◽  
Molecular Mechanisms ◽  
Potential Role ◽  
Immune Cell ◽  
Clinical Manifestations ◽  
Cell Infiltration ◽  
Cellular Mechanisms ◽  
Cytokine Levels

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The clinical manifestations of COVID-19 include dry cough, difficult breathing, fever, fatigue, and may lead to pneumonia and respiratory failure. There are significant gaps in the current understanding of whether SARS-CoV-2 attacks the CNS directly or through activation of the peripheral immune system and immune cell infiltration. Although the modality of neurological impairments associated with COVID-19 has not been thoroughly investigated, the latest studies have observed that SARS-CoV-2 induces neuroinflammation and may have severe long-term consequences. Here we review the literature on possible cellular and molecular mechanisms of SARS-CoV-2 induced-neuroinflammation. Activation of the innate immune system is associated with increased cytokine levels, chemokines, and free radicals in the SARS-CoV-2-induced pathogenic response at the blood-brain barrier (BBB). BBB disruption allows immune/inflammatory cell infiltration into the CNS activating immune resident cells (such as microglia and astrocytes). This review highlights the molecular and cellular mechanisms involved in COVID-19-induced neuroinflammation, which may lead to neuronal death. A better understanding of these mechanisms will help gain substantial knowledge about the potential role of SARS-CoV-2 in neurological changes and plan possible therapeutic intervention strategies.

Role of Epithelial-to-Mesenchymal Transition in Inflammatory Bowel Disease

2018 ◽  
Vol 13 (5) ◽  
pp. 659-668 ◽  
Author(s):  
Sara Lovisa ◽  
Giannicola Genovese ◽  
Silvio Danese
Keyword(s):  
Inflammatory Bowel Disease ◽  
Wound Healing ◽  
Bowel Disease ◽  
Molecular Mechanisms ◽  
Epithelial To Mesenchymal Transition ◽  
Clinical Manifestations ◽  
Mesenchymal Transition ◽  
Intestinal Fibrosis ◽  
Inflammatory Bowel

Abstract Intestinal fibrosis is an inevitable complication in patients with inflammatory bowel disease [IBD], occurring in its two major clinical manifestations: ulcerative colitis and Crohn’s disease. Fibrosis represents the final outcome of the host reaction to persistent inflammation, which triggers a prolonged wound healing response resulting in the excessive deposition of extracellular matrix, eventually leading to intestinal dysfunction. The process of epithelial-to-mesenchymal transition [EMT] represents an embryonic program relaunched during wound healing, fibrosis and cancer. Here we discuss the initial observations and the most recent findings highlighting the role of EMT in IBD-associated intestinal fibrosis and fistulae formation. In addition, we briefly review knowledge on the cognate process of endothelial-to-mesenchymal transition [EndMT]. Understanding EMT functionality and the molecular mechanisms underlying the activation of this mesenchymal programme will permit designing new therapeutic strategies to halt the fibrogenic response in the intestine.

scholarly journals Lipodystrophies—Disorders of the Fatty Tissue

2020 ◽  
Vol 21 (22) ◽  
pp. 8778
Author(s):  
Birgit Knebel ◽  
Dirk Müller-Wieland ◽  
Jorg Kotzka
Keyword(s):  
Insulin Resistance ◽  
Fatty Liver ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Fat Distribution ◽  
Fat Cells ◽  
Fatty Tissue ◽  
Loss Of Function ◽  
Metabolic Complications ◽  
Crucial Difference

Lipodystrophies are a heterogeneous group of physiological changes characterized by a selective loss of fatty tissue. Here, no fat cells are present, either through lack of differentiation, loss of function or premature apoptosis. As a consequence, lipids can only be stored ectopically in non-adipocytes with the major health consequences as fatty liver and insulin resistance. This is a crucial difference to being slim where the fat cells are present and store lipids if needed. A simple clinical classification of lipodystrophies is based on congenital vs. acquired and generalized vs. partial disturbance of fat distribution. Complications in patients with lipodystrophy depend on the clinical manifestations. For example, in diabetes mellitus microangiopathic complications such as nephropathy, retinopathy and neuropathy may develop. In addition, due to ectopic lipid accumulation in the liver, fatty liver hepatitis may also develop, possibly with cirrhosis. The consequences of extreme hypertriglyceridemia are typically acute pancreatitis or eruptive xanthomas. The combination of severe hyperglycemia with dyslipidemia and signs of insulin resistance can lead to premature atherosclerosis with its associated complications of coronary heart disease, peripheral vascular disease and cerebrovascular changes. Overall, lipodystrophy is rare with an estimated incidence for congenital (<1/1.000.000) and acquired (1–9/100.000) forms. Due to the rarity of the syndrome and the phenotypic range of metabolic complications, only studies with limited patient numbers can be considered. Experimental animal models are therefore useful to understand the molecular mechanisms in lipodystrophy and to identify possible therapeutic approaches.

scholarly journals Loss of Wwox Causes Defective Development of Cerebral Cortex with Hypomyelination in a Rat Model of Lethal Dwarfism with Epilepsy

2019 ◽  
Vol 20 (14) ◽  
pp. 3596 ◽  
Author(s):  
Yuki Tochigi ◽  
Yutaka Takamatsu ◽  
Jun Nakane ◽  
Rika Nakai ◽  
Kentaro Katayama ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Rat Model ◽  
Physiological Role ◽  
Early Death ◽  
Neurite Growth ◽  
Loss Of Function ◽  
Age Related ◽  
Putative Tumor Suppressor ◽  
Severe Reduction

WW domain-containing oxidoreductase (Wwox) is a putative tumor suppressor. Several germline mutations of Wwox have been associated with infant neurological disorders characterized by epilepsy, growth retardation, and early death. Less is known, however, about the pathological link between Wwox mutations and these disorders or the physiological role of Wwox in brain development. In this study, we examined age-related expression and histological localization of Wwox in forebrains as well as the effects of loss of function mutations in the Wwox gene in the immature cortex of a rat model of lethal dwarfism with epilepsy (lde/lde). Immunostaining revealed that Wwox is expressed in neurons, astrocytes, and oligodendrocytes. lde/lde cortices were characterized by a reduction in neurite growth without a reduced number of neurons, severe reduction in myelination with a reduced number of mature oligodendrocytes, and a reduction in cell populations of astrocytes and microglia. These results indicate that Wwox is essential for normal development of neurons and glial cells in the cerebral cortex.

Genetic or acquired deficits in the norepinephrine transporter: current understanding of clinical implications

2001 ◽  
Vol 3 (29) ◽  
pp. 1-10 ◽  
Author(s):  
Tahir Tellioglu ◽  
David Robertson
Keyword(s):  
Orthostatic Intolerance ◽  
Clinical Manifestations ◽  
Synaptic Cleft ◽  
Norepinephrine Transporter ◽  
Genetic Mutation ◽  
Clinical Syndrome ◽  
Loss Of Function ◽  
Direct Association ◽  
Type Gene

The norepinephrine transporter (NET) has a major role in terminating the neurochemical signal established by the neurotransmitter norepinephrine (NE) in the synaptic cleft. The NET is also the initial site of action for therapeutic antidepressants, and drugs such as cocaine and amphetamines. Polymorphisms in the NET gene have been identified, and associations with several disorders such as depression have been proposed but not established. However, evidence of a direct association between a genetic mutation of the NET and an autonomic clinical syndrome has recently emerged. A patient and her identical twin were evaluated for typical symptoms of orthostatic intolerance (OI), a disorder mainly characterised by elevated heart rate on standing, and both were found to have clinical and laboratory signs of abnormal uptake of NE. Sequence analysis of the patients' NET gene identified a mutation that resulted in more than 98% loss of function as compared with the wild-type gene. This article reconsiders the important role of the NET protein in the regulation of the nervous and cardiovascular systems, reviews the literature for its polymorphisms and their suggested clinical manifestations, and finally focuses on the effects of its defect on the pathophysiology of OI, the only confirmed direct association between a genetic mutation of the NET and a clinical syndrome.

Essential Roles for Mef2c in Lymphoid Commitment and B-Cell Function.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 377-377
Author(s):  
Sandra Stehling-Sun ◽  
Rebecca Jimenez ◽  
Andrew Hu ◽  
Fernando D. Camargo
Keyword(s):  
B Cells ◽  
B Cell ◽  
Molecular Mechanisms ◽  
Muscle Development ◽  
Cell Function ◽  
Physiological Role ◽  
Erythroid Differentiation ◽  
Hematopoietic Stem ◽  
Interleukin 7

Abstract MEF2 transcription factors are well-established regulators of muscle development. Recently, work in murine models has identified one of these factors, Mef2c, as an important regulator in the pathogenesis and the development of acute myeloid leukemia (AML). However, little is know about the molecular mechanism and physiological role of Mef2c in hematopoiesis. Using conditional gene ablation, we have discovered an unexpected role for MEF2c in hematopoietic stem cells (HSCs), where it is required for pan-lymphoid commitment. Competitive repopulation experiments using Mef2c-null HSCs deleted by means of the Mx1-Cre/poly(IC) approach, revealed completely normal monocytic, granulocytic and erythroid differentiation capacities by mutant cells. Generation and renewal of myeloid progenitors and HSCs was also normal. However, contribution to lymphoid lineages (T-cells, B-cells and natural killer cells) was dramatically reduced. Mef2c-deleted HSCs were able to generate lymphoid primed multipotent progenitors (LMPPs) and expressed normal levels of Flt-3 and the master lymphoid regulator ikaros. However, expression of the interleukin-7 receptor (IL-7R) and the number of phenotypically defined common lymphoid progenitors (CLPs) were substantially reduced. We have found two conserved Mef2c-binding sites in the promoter of the Il-7R gene, indicating that Mef2c could directly regulate Il-7R transcription. This and other potential molecular mechanisms of Mef2c-mediated lymphoid commitment will be discussed. We have also studied the effects of lineage-specific deletion of Mef2c in both myeloid and lymphoid populations. Whereas deletion in myelomonocytic cells using the LysM-Cre strain resulted in no anomalies, B-cell specific ablation with the CD19-Cre line revealed major phenotypical and functional abnormalities. CD19-Cre:Mef2cf/f mice show impaired germinal center formation and reduced antibody production in response to T-cell dependent antigens. In addition Mef2c-null mature B-cells fail to express the mature marker CD23, the low affinity receptor for IgE, which we show is a direct transcriptional target. As a consequence of CD23 reduction, CD19-Cre:Mef2cf/f mice have increased IgE production, thus indicating a potential role of Mef2c in allergic disease. Our work here sheds new light on the molecular mechanisms of lymphopoiesis and identifies MEF2 factors as critical hematopoietic transcriptional regulators.

Guwiyang Wurra–‘Fire Mouse’: a global gene knockout model for TSPO/PBR drug development, loss-of-function and mechanisms of compensation studies

2015 ◽  
Vol 43 (4) ◽  
pp. 553-558 ◽  
Author(s):  
Ryan J. Middleton ◽  
Guo-Jun Liu ◽  
Richard B. Banati
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Gene Knockout ◽  
Physiological Role ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Benzodiazepine Receptor ◽  
Translocator Protein ◽  
Loss Of Function ◽  
Recent Developments

The highly conserved 18-kDa translocator protein (TSPO) or peripheral benzodiazepine receptor (PBR), is being investigated as a diagnostic and therapeutic target for disease conditions ranging from inflammation to neurodegeneration and behavioural illnesses. Many functions have been attributed to TSPO/PBR including a role in the mitochondrial permeability transition pore (MPTP), steroidogenesis and energy metabolism. In this review, we detail the recent developments in determining the physiological role of TSPO/PBR, specifically based on data obtained from the recently generated Tspo knockout mouse models. In addition to defining the role of TSPO/PBR, we also describe the value of Tspo knockout mice in determining the selectivity, specificity and presence of any off-target effects of TSPO/PBR ligands.

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