scholarly journals Uncovering the Neuroprotective Mechanisms of Curcumin on Transthyretin Amyloidosis

2019 ◽  
Vol 20 (6) ◽  
pp. 1287 ◽  
Author(s):  
Nelson Ferreira ◽  
Maria Saraiva ◽  
Maria Almeida
Keyword(s):  
Immune System ◽  
Amino Acid ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Current Work ◽  
Amino Acid Substitutions ◽  
Therapeutic Approaches ◽  
Transthyretin Amyloidosis ◽  
Chemical Chaperones ◽  
Attr Amyloidosis

Transthyretin (TTR) amyloidoses (ATTR amyloidosis) are diseases associated with transthyretin (TTR) misfolding, aggregation and extracellular deposition in tissues as amyloid. Clinical manifestations of the disease are variable and include mainly polyneuropathy and/or cardiomyopathy. The reasons why TTR forms aggregates and amyloid are related with amino acid substitutions in the protein due to mutations, or with environmental alterations associated with aging, that make the protein more unstable and prone to aggregation. According to this model, several therapeutic approaches have been proposed for the diseases that range from stabilization of TTR, using chemical chaperones, to clearance of the aggregated protein deposited in tissues in the form of oligomers or small aggregates, by the action of disruptors or by activation of the immune system. Interestingly, different studies revealed that curcumin presents anti-amyloid properties, targeting multiple steps in the ATTR amyloidogenic cascade. The effects of curcumin on ATTR amyloidosis will be reviewed and discussed in the current work in order to contribute to knowledge of the molecular mechanisms involved in TTR amyloidosis and propose more efficient drugs for therapy.

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.

scholarly journals Amino Acid Substitutions in Mosaic Penicillin-Binding Protein 2 Associated with Reduced Susceptibility to Cefixime in Clinical Isolates of Neisseria gonorrhoeae

2006 ◽  
Vol 50 (11) ◽  
pp. 3638-3645 ◽  
Author(s):  
Sho Takahata ◽  
Nami Senju ◽  
Yumi Osaki ◽  
Takuji Yoshida ◽  
Takashi Ida
Keyword(s):  
Amino Acid ◽  
Neisseria Gonorrhoeae ◽  
Molecular Mechanisms ◽  
Binding Protein ◽  
Complete Sequence ◽  
Clinical Isolates ◽  
Amino Acid Substitutions ◽  
Penicillin Binding Protein ◽  
Fourfold Increase ◽  
Genes Encoding

ABSTRACT The molecular mechanisms of reduced susceptibility to cefixime in clinical isolates of Neisseria gonorrhoeae, particularly amino acid substitutions in mosaic penicillin-binding protein 2 (PBP2), were examined. The complete sequence of ponA, penA, and por genes, encoding, respectively, PBP1, PBP2, and porin, were determined for 58 strains isolated in 2002 from Japan. Replacement of leucine 421 by proline in PBP1 and the mosaic-like structure of PBP2 were detected in 48 strains (82.8%) and 28 strains (48.3%), respectively. The presence of mosaic PBP2 was the main cause of the elevated cefixime MIC (4- to 64-fold). In order to identify the mutations responsible for the reduced susceptibility to cefixime in isolates with mosaic PBP2, penA genes with various mutations were transferred to a susceptible strain by genetic transformation. The susceptibility of partial recombinants and site-directed mutants revealed that the replacement of glycine 545 by serine (G545S) was the primary mutation, which led to a two- to fourfold increase in resistance to cephems. Replacement of isoleucine 312 by methionine (I312M) and valine 316 by threonine (V316T), in the presence of the G545S mutation, reduced susceptibility to cefixime, ceftibuten, and cefpodoxime by an additional fourfold. Therefore, three mutations (G545S, I312M, and V316T) in mosaic PBP2 were identified as the amino acid substitutions responsible for reduced susceptibility to cefixime in N. gonorrhoeae.

scholarly journals Targeted Metabolomic Analysis of a Mucopolysaccharidosis IIIB Mouse Model Reveals an Imbalance of Branched-Chain Amino Acid and Fatty Acid Metabolism

2020 ◽  
Vol 21 (12) ◽  
pp. 4211 ◽  
Author(s):  
Valeria De Pasquale ◽  
Marianna Caterino ◽  
Michele Costanzo ◽  
Roberta Fedele ◽  
Margherita Ruoppolo ◽  
...  
Keyword(s):  
Amino Acids ◽  
Fatty Acid ◽  
Amino Acid ◽  
Mouse Model ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Neurological Impairment ◽  
Genetic Mutation ◽  
Inherited Disorders ◽  
Branched Chain

Mucopolysaccharidoses (MPSs) are inherited disorders of the glycosaminoglycan (GAG) metabolism. The defective digestion of GAGs within the intralysosomal compartment of affected patients leads to a broad spectrum of clinical manifestations ranging from cardiovascular disease to neurological impairment. The molecular mechanisms underlying the progression of the disease downstream of the genetic mutation of genes encoding for lysosomal enzymes still remain unclear. Here, we applied a targeted metabolomic approach to a mouse model of PS IIIB, using a platform dedicated to the diagnosis of inherited metabolic disorders, in order to identify amino acid and fatty acid metabolic pathway alterations or the manifestations of other metabolic phenotypes. Our analysis highlighted an increase in the levels of branched-chain amino acids (BCAAs: Val, Ile, and Leu), aromatic amino acids (Tyr and Phe), free carnitine, and acylcarnitines in the liver and heart tissues of MPS IIIB mice as compared to the wild type (WT). Moreover, Ala, Met, Glu, Gly, Arg, Orn, and Cit amino acids were also found upregulated in the liver of MPS IIIB mice. These findings show a specific impairment of the BCAA and fatty acid catabolism in the heart of MPS IIIB mice. In the liver of affected mice, the glucose-alanine cycle and urea cycle resulted in being altered alongside a deregulation of the BCAA metabolism. Thus, our data demonstrate that an accumulation of BCAAs occurs secondary to lysosomal GAG storage, in both the liver and the heart of MPS IIIB mice. Since BCAAs regulate the biogenesis of lysosomes and autophagy mechanisms through mTOR signaling, impacting on lipid metabolism, this condition might contribute to the progression of the MPS IIIB disease.

scholarly journals A Yeast-Based Model for Hereditary Motor and Sensory Neuropathies: A Simple System for Complex, Heterogeneous Diseases

2020 ◽  
Vol 21 (12) ◽  
pp. 4277 ◽  
Author(s):  
Weronika Rzepnikowska ◽  
Joanna Kaminska ◽  
Dagmara Kabzińska ◽  
Katarzyna Binięda ◽  
Andrzej Kochański
Keyword(s):  
Molecular Mechanisms ◽  
Genetic Diagnosis ◽  
Clinical Manifestations ◽  
Model System ◽  
Research Field ◽  
Therapeutic Approaches ◽  
Rare Disorders ◽  
Advantages And Disadvantages ◽  
Pathogenic Variants ◽  
Disease Subtypes

Charcot–Marie–Tooth (CMT) disease encompasses a group of rare disorders that are characterized by similar clinical manifestations and a high genetic heterogeneity. Such excessive diversity presents many problems. Firstly, it makes a proper genetic diagnosis much more difficult and, even when using the most advanced tools, does not guarantee that the cause of the disease will be revealed. Secondly, the molecular mechanisms underlying the observed symptoms are extremely diverse and are probably different for most of the disease subtypes. Finally, there is no possibility of finding one efficient cure for all, or even the majority of CMT diseases. Every subtype of CMT needs an individual approach backed up by its own research field. Thus, it is little surprise that our knowledge of CMT disease as a whole is selective and therapeutic approaches are limited. There is an urgent need to develop new CMT models to fill the gaps. In this review, we discuss the advantages and disadvantages of yeast as a model system in which to study CMT diseases. We show how this single-cell organism may be used to discriminate between pathogenic variants, to uncover the mechanism of pathogenesis, and to discover new therapies for CMT disease.

scholarly journals Amino acid substitutions in the FXYD motif enhance phospholemman-induced modulation of cardiac L-type calcium channels

2010 ◽  
Vol 299 (5) ◽  
pp. C1203-C1211 ◽  
Author(s):  
Kai Guo ◽  
Xianming Wang ◽  
Guofeng Gao ◽  
Congxin Huang ◽  
Keith S. Elmslie ◽  
...  
Keyword(s):  
Amino Acid ◽  
Calcium Channels ◽  
Molecular Mechanisms ◽  
Channel Gating ◽  
Fine Tuning ◽  
Amino Acid Substitutions ◽  
Dependent Inactivation ◽  
Voltage Dependent ◽  
Kinetics Of

We have found that phospholemman (PLM) associates with and modulates the gating of cardiac L-type calcium channels (Wang et al., Biophys J 98: 1149–1159, 2010). The short 17 amino acid extracellular NH2-terminal domain of PLM contains a highly conserved PFTYD sequence that defines it as a member of the FXYD family of ion transport regulators. Although we have learned a great deal about PLM-dependent changes in calcium channel gating, little is known regarding the molecular mechanisms underlying the observed changes. Therefore, we investigated the role of the PFTYD segment in the modulation of cardiac calcium channels by individually replacing Pro-8, Phe-9, Thr-10, Tyr-11, and Asp-12 with alanine (P8A, F9A, T10A, Y11A, D12A). In addition, Asp-12 was changed to lysine (D12K) and cysteine (D12C). As expected, wild-type PLM significantly slows channel activation and deactivation and enhances voltage-dependent inactivation (VDI). We were surprised to find that amino acid substitutions at Thr-10 and Asp-12 significantly enhanced the ability of PLM to modulate CaV1.2 gating. T10A exhibited a twofold enhancement of PLM-induced slowing of activation, whereas D12K and D12C dramatically enhanced PLM-induced increase of VDI. The PLM-induced slowing of channel closing was abrogated by D12A and D12C, whereas D12K and T10A failed to impact this effect. These studies demonstrate that the PFXYD motif is not necessary for the association of PLM with CaV1.2. Instead, since altering the chemical and/or physical properties of the PFXYD segment alters the relative magnitudes of opposing PLM-induced effects on CaV1.2 channel gating, PLM appears to play an important role in fine tuning the gating kinetics of cardiac calcium channels and likely plays an important role in shaping the cardiac action potential and regulating Ca2+ dynamics in the heart.

scholarly journals Epidemiological Survey of Amoxicillin-Clavulanate Resistance and Corresponding Molecular Mechanisms in Escherichia coliIsolates in France: New Genetic Features ofblaTEM Genes

2000 ◽  
Vol 44 (10) ◽  
pp. 2709-2714 ◽  
Author(s):  
V. Leflon-Guibout ◽  
V. Speldooren ◽  
B. Heym ◽  
M.-H. Nicolas-Chanoine
Keyword(s):  
Amino Acid ◽  
Molecular Mechanisms ◽  
Consensus Sequence ◽  
Epidemiological Survey ◽  
Amino Acid Substitutions ◽  
Single Strand Conformational Polymorphism ◽  
E Coli ◽  
Genetic Features ◽  
Amoxicillin Clavulanate ◽  
Medical Wards

ABSTRACT Amoxicillin-clavulanate resistance (MIC >16 μg/ml) and the corresponding molecular mechanisms were prospectively studied inEscherichia coli over a 3-year period (1996 to 1998) in 14 French hospitals. The overall frequency of resistant E. coli isolates remained stable at about 5% over this period. The highest frequency of resistant isolates (10 to 15%) was observed, independently of the year, among E. coli isolated from lower respiratory tract samples, and the isolation rate of resistant strains was significantly higher in surgical wards than in medical wards in 1998 (7.8 versus 2.8%). The two most frequent mechanisms of resistance for the 3 years were the hyperproduction of the chromosomal class C β-lactamase (48, 38.4, and 39.7%) and the production of inhibitor-resistant TEM (IRT) enzymes (30.4, 37.2, and 41.2%). By using the single-strand conformational polymorphism–PCR technique and sequencing methods, we determined that 59 IRT enzymes corresponded to previously described IRT enzymes whereas 8 were new. Three of these new enzymes derived from TEM-1 by only one amino acid substitution (Ser130Gly, Arg244Gly, and Asn276Asp), whereas three others derived by two amino acid substitutions (Met69Leu and Arg244Ser, Met69Leu and Ile127Val, and Met69Val and Arg275Gln). The two remaining new IRTs showed three amino acid substitutions (Met69Val, Trp165Arg, and Asn276Asp and Met69Ile, Trp165Cys, and Arg275Gln). New genetic features were also found inbla TEM genes, namely,bla TEM-1B with either the promotersPa and Pb, P4, or a promoter displaying a C→G transversion at position 3 of the −35 consensus sequence and new bla TEM genes, notably one encoding TEM-1 but possessing the silent mutations originally described in bla TEM-2 and then in somebla TEM-encoding IRT enzymes.

scholarly journals SARS-CoV-2: a new threat

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Cristina A. López Rodríguez ◽  
Marc Boigues Pons ◽  
Bibiana Quirant Sánchez ◽  
Aina Teniente Serra ◽  
Joan Climent Martí ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Rna Virus ◽  
Structural Characteristics ◽  
Clinical Manifestations ◽  
Diagnostic Techniques ◽  
Therapeutic Approaches ◽  
Lymphocyte Populations ◽  
Control And Eradication

AbstractBackgroundThe pandemic caused by the emergence of the new SARS-CoV-2 virus worldwide has had a major impact at all levels and has forced in-depth research into its behavior, pathogenicity and treatment.ContentThis review provides an overview of various aspects of the virus and the immune response it triggers, as well as a description of the different diagnostic and therapeutic approaches adopted.SummarySARS-COV-2 is a RNA virus with some peculiarities that make it different from its predecessors SARS-CoV and MERS. Given its structural characteristics and pathogenesis, it can cause different clinical manifestations as the disease progresses. The immune system has been proven to play a major role in the response to this virus and, therefore, the study of antibodies and lymphocyte populations during the different stages of the disease is crucial.OutlookThe knowledge of the effect of the virus and the immune response is crucial for the development of good quality vaccines, therapies and diagnostic techniques, which are essential for the control and eradication of the disease.

scholarly journals Experience with tafamidis in a patient with transthyretin amyloidosis

Kardiologiia ◽  
2020 ◽  
Vol 60 (3) ◽  
pp. 155-160
Author(s):  
S. N. Nasonova ◽  
I. V. Zhirov ◽  
M. M. Magomedov ◽  
M. A. Saidova ◽  
Yu. F. Osmolovskaya ◽  
...  
Keyword(s):  
Heart Failure ◽  
Nervous System ◽  
Genetic Disease ◽  
Clinical Case ◽  
Clinical Manifestations ◽  
Functional Class ◽  
Class Iii ◽  
Transthyretin Amyloidosis ◽  
Attr Amyloidosis ◽  
Heart Injury

Transthyretin amyloidosis (ATTR) is a threatening and severe genetic disease characterized by damages to organs and systems caused by a pathological protein transthyretin produced in the liver. Clinical manifestations of this disease vary from injuries of the nervous system to injuries of the cardiovascular system. Prognosis for ATTR-amyloidosis remains unfavorable. The absence of pathognomonic symptoms complicates diagnostics of this disease, which tends to simulate other conditions. At present, medicines exist, which are pathogenetic in the treatment of ATTR-amyloidosis. The article describes a clinical case of ATTR-amyloidosis with primary heart injury complicated with functional class III chronic heart failure during the tafamidis treatment.

scholarly journals Subretinal fibrosis in neovascular age-related macular degeneration: current concepts, therapeutic avenues, and future perspectives

2021 ◽  
Author(s):  
Louis Tenbrock ◽  
Julian Wolf ◽  
Stefaniya Boneva ◽  
Anja Schlecht ◽  
Hansjürgen Agostini ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Age Related Macular Degeneration ◽  
Matrix Proteins ◽  
Therapeutic Approaches ◽  
Aggressive Form ◽  
Age Related ◽  
Mammalian Retina ◽  
Subretinal Fibrosis

AbstractAge-related macular degeneration (AMD) is a progressive, degenerative disease of the human retina which in its most aggressive form is associated with the formation of macular neovascularization (MNV) and subretinal fibrosis leading to irreversible blindness. MNVs contain blood vessels as well as infiltrating immune cells, myofibroblasts, and excessive amounts of extracellular matrix proteins such as collagens, fibronectin, and laminin which disrupts retinal function and triggers neurodegeneration. In the mammalian retina, damaged neurons cannot be replaced by tissue regeneration, and subretinal MNV and fibrosis persist and thus fuel degeneration and visual loss. This review provides an overview of subretinal fibrosis in neovascular AMD, by summarizing its clinical manifestations, exploring the current understanding of the underlying cellular and molecular mechanisms and discussing potential therapeutic approaches to inhibit subretinal fibrosis in the future.

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