Delineating the expanding phenotype of HERC2 ‐related disorders: The impact of biallelic loss of function versus missense variation

2021 ◽  
Author(s):  
Krista M. Vincent ◽  
Alison Eaton ◽  
Vahid Reza Yassaee ◽  
Mohammad Miryounesi ◽  
Feyzollah Hashemi‐Gorji ◽  
...  
Keyword(s):  
Function Versus ◽  
Loss Of Function ◽  
Missense Variation ◽  
The Impact

scholarly journals ATP13A2 Regulates Cellular α-Synuclein Multimerization, Membrane Association, and Externalization

2021 ◽  
Vol 22 (5) ◽  
pp. 2689
Author(s):  
Jianmin Si ◽  
Chris Van den Haute ◽  
Evy Lobbestael ◽  
Shaun Martin ◽  
Sarah van Veen ◽  
...  
Keyword(s):  
Membrane Integrity ◽  
Ubiquitin Proteasome System ◽  
Regulatory Function ◽  
Membrane Association ◽  
Loss Of Function ◽  
Atypical Form ◽  
Polyamine Transport ◽  
Independent Functions ◽  
Ubiquitin Proteasome ◽  
The Impact

ATP13A2, a late endo-/lysosomal polyamine transporter, is implicated in a variety of neurodegenerative diseases, including Parkinson’s disease and Kufor–Rakeb syndrome, an early-onset atypical form of parkinsonism. Loss-of-function mutations in ATP13A2 result in lysosomal deficiency as a consequence of impaired lysosomal export of the polyamines spermine/spermidine. Furthermore, accumulating evidence suggests the involvement of ATP13A2 in regulating the fate of α-synuclein, such as cytoplasmic accumulation and external release. However, no consensus has yet been reached on the mechanisms underlying these effects. Here, we aimed to gain more insight into how ATP13A2 is linked to α-synuclein biology in cell models with modified ATP13A2 activity. We found that loss of ATP13A2 impairs lysosomal membrane integrity and induces α-synuclein multimerization at the membrane, which is enhanced in conditions of oxidative stress or exposure to spermine. In contrast, overexpression of ATP13A2 wildtype (WT) had a protective effect on α-synuclein multimerization, which corresponded with reduced αsyn membrane association and stimulation of the ubiquitin-proteasome system. We also found that ATP13A2 promoted the secretion of α-synuclein through nanovesicles. Interestingly, the catalytically inactive ATP13A2 D508N mutant also affected polyubiquitination and externalization of α-synuclein multimers, suggesting a regulatory function independent of the ATPase and transport activity. In conclusion, our study demonstrates the impact of ATP13A2 on α-synuclein multimerization via polyamine transport dependent and independent functions.

A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway

2021 ◽  
pp. 1-10
Author(s):  
Varvara Kanti ◽  
Lia Puder ◽  
Irina Jahnke ◽  
Philipp Maximilian Krabusch ◽  
Jan Kottner ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Skin Pigmentation ◽  
Gene Mutations ◽  
Continuous Treatment ◽  
Whole Body ◽  
Hair Color ◽  
Phase 2 ◽  
Loss Of Function ◽  
The Impact ◽  
Over Time

<b><i>Background and Objectives:</i></b> Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist <i>setmelanotide</i> in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with <i>setmelanotide,</i> changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. <b><i>Methods:</i></b> In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist <i>setmelanotide</i>. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. <b><i>Results:</i></b> We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of <i>setmelanotide</i> treatment. <b><i>Discussion:</i></b> <i>Setmelanotide</i> treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

scholarly journals Preservation of epoxyeicosatrienoic acid bioavailability prevents renal allograft dysfunction and cardiovascular alterations in kidney transplant recipients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thomas Duflot ◽  
Charlotte Laurent ◽  
Anne Soudey ◽  
Xavier Fonrose ◽  
Mouad Hamzaoui ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Kidney Transplant ◽  
Plasma Levels ◽  
Renal Allograft ◽  
Transplant Recipients ◽  
Loss Of Function ◽  
Kidney Transplant Recipients ◽  
Allograft Dysfunction ◽  
Allograft Function ◽  
The Impact

AbstractThis study addressed the hypothesis that epoxyeicosatrienoic acids (EETs) synthesized by CYP450 and catabolized by soluble epoxide hydrolase (sEH) are involved in the maintenance of renal allograft function, either directly or through modulation of cardiovascular function. The impact of single nucleotide polymorphisms (SNPs) in the sEH gene EPHX2 and CYP450 on renal and vascular function, plasma levels of EETs and peripheral blood monuclear cell sEH activity was assessed in 79 kidney transplant recipients explored at least one year after transplantation. Additional experiments in a mouse model mimicking the ischemia–reperfusion (I/R) injury suffered by the transplanted kidney evaluated the cardiovascular and renal effects of the sEH inhibitor t-AUCB administered in drinking water (10 mg/l) during 28 days after surgery. There was a long-term protective effect of the sEH SNP rs6558004, which increased EET plasma levels, on renal allograft function and a deleterious effect of K55R, which increased sEH activity. Surprisingly, the loss-of-function CYP2C9*3 was associated with a better renal function without affecting EET levels. R287Q SNP, which decreased sEH activity, was protective against vascular dysfunction while CYP2C8*3 and 2C9*2 loss-of-function SNP, altered endothelial function by reducing flow-induced EET release. In I/R mice, sEH inhibition reduced kidney lesions, prevented cardiac fibrosis and dysfunction as well as preserved endothelial function. The preservation of EET bioavailability may prevent allograft dysfunction and improve cardiovascular disease in kidney transplant recipients. Inhibition of sEH appears thus as a novel therapeutic option but its impact on other epoxyfatty acids should be carefully evaluated.

scholarly journals Codon harmonization reduces amino acid misincorporation in bacterially expressed P. falciparum proteins and improves their immunogenicity

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Neeraja Punde ◽  
Jennifer Kooken ◽  
Dagmar Leary ◽  
Patricia M. Legler ◽  
Evelina Angov
Keyword(s):  
Protein Structure ◽  
Amino Acid ◽  
Codon Usage ◽  
Dna Sequences ◽  
Structural Integrity ◽  
Host Cells ◽  
Loss Of Function ◽  
Species Specific ◽  
And Function ◽  
The Impact

Abstract Codon usage frequency influences protein structure and function. The frequency with which codons are used potentially impacts primary, secondary and tertiary protein structure. Poor expression, loss of function, insolubility, or truncation can result from species-specific differences in codon usage. “Codon harmonization” more closely aligns native codon usage frequencies with those of the expression host particularly within putative inter-domain segments where slower rates of translation may play a role in protein folding. Heterologous expression of Plasmodium falciparum genes in Escherichia coli has been a challenge due to their AT-rich codon bias and the highly repetitive DNA sequences. Here, codon harmonization was applied to the malarial antigen, CelTOS (Cell-traversal protein for ookinetes and sporozoites). CelTOS is a highly conserved P. falciparum protein involved in cellular traversal through mosquito and vertebrate host cells. It reversibly refolds after thermal denaturation making it a desirable malarial vaccine candidate. Protein expressed in E. coli from a codon harmonized sequence of P. falciparum CelTOS (CH-PfCelTOS) was compared with protein expressed from the native codon sequence (N-PfCelTOS) to assess the impact of codon usage on protein expression levels, solubility, yield, stability, structural integrity, recognition with CelTOS-specific mAbs and immunogenicity in mice. While the translated proteins were expected to be identical, the translated products produced from the codon-harmonized sequence differed in helical content and showed a smaller distribution of polypeptides in mass spectra indicating lower heterogeneity of the codon harmonized version and fewer amino acid misincorporations. Substitutions of hydrophobic-to-hydrophobic amino acid were observed more commonly than any other. CH-PfCelTOS induced significantly higher antibody levels compared with N-PfCelTOS; however, no significant differences in either IFN-γ or IL-4 cellular responses were detected between the two antigens.

scholarly journals Clinical, Genetics, and Bioinformatic Characterization of Mutations Affecting an Essential Region of PLS3 in Patients with BMND18

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ting Chen ◽  
Haiying Wu ◽  
Chenxi Zhang ◽  
Jiarong Feng ◽  
Linqi Chen ◽  
...  
Keyword(s):  
Novel Mutation ◽  
Homology Modelling ◽  
Gene Sequencing ◽  
Bioinformatic Analysis ◽  
Actin Binding ◽  
Clinical Genetics ◽  
Loss Of Function ◽  
Mineral Density ◽  
Trait Locus ◽  
The Impact

Background. Bone mineral density quantitative trait locus 18 (BMND18, OMIM #300910) is a type of early-onset osteogenesis imperfecta (OI) caused by loss-of-function mutations in the PLS3 gene, which encodes plastin-3, a key protein in the formation of actin bundles throughout the cytoskeleton. Here, we report a patient with PLS3 mutation caused BMND18 and evaluated all the reported disease-causing mutations by bioinformatic analysis. Methods. Targeted gene sequencing was performed to find the disease-causing mutation in our patient. Bioinformatic analyses mainly including homology modelling and molecular dynamics stimulation were conducted to explore the impact of the previously reported mutations on plastin-3. Results. Gene sequencing showed a novel nonsense mutation (c.745G > T, p.E249X), which locates at a highly conserved region containing residues p.240–266 (LOOP-1) in the PLS3 gene. Further bioinformatic analyses of the previously reported mutations revealed that LOOP-1 is predicted to physically connect the calponin-homology 1 (CH1) and CH2 domains of the ABD1 fragment and spatially locates within the interface of ABD1 and ABD2. It is crucial to the conformation transition and actin-binding function of plastin-3. Conclusions. This report identified a novel mutation that truncates the PLS3 gene. Moreover, bioinformatic analyses of the previous reported mutations in PLS3 gene lead us to find a critical LOOP-1 region of plastin-3 mutations at which may be detrimental to the integral conformation of plastin-3 and thus affect its binding to actin filament.

Abstract 14849: Gender Differences in Impact of CYP2C19 Polymorphism and Low Grade Inflammation on Coronary Spasm in Patients with Vasospastic Angina (VSA)

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Tomonori Akasaka ◽  
Seiji Hokimoto ◽  
Noriaki Tabata ◽  
Kenji Sakamoto ◽  
Kenichi Tsujita ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Artery Spasm ◽  
Coronary Spasm ◽  
Control Group ◽  
Low Grade ◽  
Cyp2c19 Genotype ◽  
Loss Of Function ◽  
Hs Crp ◽  
The Impact ◽  
Low Grade Inflammation

Background: Several cytochrome P450 (CYP) enzyme families have been identified in extra hepatic tissues such as heart, vasculature, kidney, and lung. CYP2C19 localized in vascular smooth muscle and endothelium contributes to the regulation of vascular tone and homeostasis. However, it is unknown whether CYP2C19 genotype is associated with the vascular tonus in patients with VSA. The aim of this study was to examine the impact of CYP2C19 genotype on coronary artery spasm in patients with VSA. Methods: We examined the distribution of CYP2C19 genotype in patients with VSA (n=129) who were diagnosed by intra-coronary acetylcholine infusion test and healthy subjects (n=455) as control group. CYP2C19 genotypes were divided into 3 groups; (1) CYP2C19*1/*1: EM, (2) one loss-of-function allele (*1/*2, *1/*3: IM), and (3) two loss-of-function alleles (*2/*2, *2/*3, *3/*3: PM). Moreover, we measured the level of high-sensitive CRP (hs-CRP) as a degree of low glade inflammation in each group. Results: The ratios of CYP2C19 genotype (EM, IM, and PM) were 30, 42, and 28% in VSA group, and 32, 49, and 19% in control group. In short, PM frequency was significantly higher in VSA than in control (28% vs 19%, P=0.026). In VSA group, the ratios of CYP2C19 genotype were 36, 44, and 20% in male, and 20, 39, and 41% in female, respectively. Briefly, the PM frequency was significantly higher in female than in male (41% vs 20%, P<0.001). Moreover, the level of hs-CRP was significantly higher in VSA group than in control group (0.17±0.367 vs 0.10.±0.240, P=0.02). When patients were stratified by gender, the level of hs-CRP was significantly higher in VSA group in female (0.11±0.198 vs 0.06±0.105, P=0.031) and male (0.20±0.438 vs 0.12±0.277, P=0.044). Multivariate analysis for coronary spasm indicated high age, hypertension, and high level of hs-CRP as predictive factors among all subjects. PM is a predictive factor for coronary spasm in female group only (OR3.1, 95%RI 1.525-6.317, P=0.002), but not in male (OR0.829, 95%RI 0.453-1.518, P=0.543). Conclusion: The CYP2C19 two loss-of-function alleles (PM) and low grade inflammation may be associated with pathophysiology of coronary artery spasm and the regulation of coronary tonus, especially in female.

scholarly journals Liver X Receptor Nuclear Receptors Are Transcriptional Regulators of Dendritic Cell Chemotaxis

2018 ◽  
Vol 38 (10) ◽  
Author(s):  
Susana Beceiro ◽  
Attila Pap ◽  
Zsolt Czimmerer ◽  
Tamer Sallam ◽  
Jose A. Guillén ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Low Density Lipoprotein ◽  
Myeloid Cells ◽  
Density Lipoprotein ◽  
Loss Of Function ◽  
Transcriptional Responses ◽  
Cd38 Expression ◽  
The Impact

ABSTRACTThe liver X receptors (LXRs) are ligand-activated nuclear receptors with established roles in the maintenance of lipid homeostasis in multiple tissues. LXRs exert additional biological functions as negative regulators of inflammation, particularly in macrophages. However, the transcriptional responses controlled by LXRs in other myeloid cells, such as dendritic cells (DCs), are still poorly understood. Here we used gain- and loss-of-function models to characterize the impact of LXR deficiency on DC activation programs. Our results identified an LXR-dependent pathway that is important for DC chemotaxis. LXR-deficient mature DCs are defective in stimulus-induced migrationin vitroandin vivo. Mechanistically, we show that LXRs facilitate DC chemotactic signaling by regulating the expression of CD38, an ectoenzyme important for leukocyte trafficking. Pharmacological or genetic inactivation of CD38 activity abolished the LXR-dependent induction of DC chemotaxis. Using the low-density lipoprotein receptor-deficient (LDLR−/−) LDLR−/−mouse model of atherosclerosis, we also demonstrated that hematopoietic CD38 expression is important for the accumulation of lipid-laden myeloid cells in lesions, suggesting that CD38 is a key factor in leukocyte migration during atherogenesis. Collectively, our results demonstrate that LXRs are required for the efficient emigration of DCs in response to chemotactic signals during inflammation.

scholarly journals Increased antibiotic susceptibility in Neisseria gonorrhoeae through adaptation to the cervical environment

2020 ◽  
Author(s):  
Kevin C Ma ◽  
Tatum D Mortimer ◽  
Allison L Hicks ◽  
Nicole E Wheeler ◽  
Leonor Sánchez-Busó ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antibiotic Susceptibility ◽  
Microbial Population ◽  
Population Genomics ◽  
Efflux Pump ◽  
Loss Of Function ◽  
Environmental Pressures ◽  
Genome Wide ◽  
A Subunit ◽  
The Impact

AbstractNeisseria gonorrhoeae is an urgent public health threat due to rapidly increasing incidence and antibiotic resistance. In contrast with the trend of increasing resistance, clinical isolates that have reverted to susceptibility regularly appear, prompting questions about which pressures compete with antibiotics to shape gonococcal evolution. Here, we used genome-wide association on the largest collection of N. gonorrhoeae isolates to date (n=4852) to identify loss-of-function (LOF) mutations in the efflux pump mtrCDE operon as a mechanism of increased antibiotic susceptibility and demonstrate that these mutations are overrepresented in cervical isolates relative to urethral isolates (odds ratio (OR) = 3.74, 95% CI [1.98-6.70]). In support of a model in which pump expression incurs a fitness cost in this niche, cervical isolates were also enriched relative to urethral isolates in LOF mutations in the mtrCDE activator mtrA (OR = 8.60, 95% CI [4.96-14.57]) and in farA, a subunit of the FarAB efflux pump (OR = 6.25, 95% CI [3.90-9.83]). In total, approximately 2 in 5 cervical isolates (42.6%) contained a LOF mutation in either the efflux pump components mtrC or farA or the activator mtrA. Our findings extend beyond N. gonorrhoeae to other Neisseria: mtrC LOF mutations are rare (<1%) in the primarily nasopharyngeal-colonizing N. meningitidis in a collection of 14,798 genomes but enriched in a heterosexual urethritis-associated lineage (8.6%, p = 9.90×10−5), indicating that efflux pump downregulation contributes broadly to the adaptation of pathogenic Neisseria to the female urogenital tract. Overall, our findings highlight the impact of integrating microbial population genomics with host metadata and demonstrate how host environmental pressures can lead to increased antibiotic susceptibility.

scholarly journals The Okur-Chung Neurodevelopmental Syndrome (OCNDS) mutation CK2K198R leads to a rewiring of kinase specificity

2021 ◽  
Author(s):  
Danielle M Caefer ◽  
Nhat Q Phan ◽  
Jennifer C Liddle ◽  
Jeremy L Balsbaugh ◽  
Joseph P O’Shea ◽  
...  
Keyword(s):  
High Resolution ◽  
Substrate Specificity ◽  
Tyrosine Phosphorylation ◽  
Initial Step ◽  
Loss Of Function ◽  
Scoring Method ◽  
Disease Condition ◽  
The Impact ◽  
First Time

AbstractOkur-Chung Neurodevelopmental Syndrome (OCNDS) is caused by heterozygous mutations to the CSNK2A1 gene, which encodes the alpha subunit of casein kinase II (CK2). The most frequently occurring mutation is lysine 198 to arginine (K198R). To investigate the impact of this mutation, we first generated a high-resolution phosphorylation motif of CK2WT, including the first characterization of specificity for tyrosine phosphorylation activity. A second high resolution motif representing CK2K198R substrate specificity was also generated. Here we report for the first time the impact of the OCNDS associated CK2K198R mutation. Contrary to prior speculation, the mutation does not result in a loss of function, but rather shifts the substrate specificity of the kinase. Broadly speaking the mutation leads to 1) a decreased preference for acidic residues in the +1 position, 2) a decreased preference for threonine phosphorylation, 3) an increased preference for tyrosine phosphorylation, and 4) an alteration of the tyrosine phosphorylation specificity motif. To further investigate the result of this mutation we have developed a probability-based scoring method, allowing us to predict shifts in phosphorylation in the K198R mutant relative to the wild type kinase. As an initial step we have applied the methodology to the set of axonally localized ion channels in an effort to uncover potential alterations of the phosphoproteome associated with the OCNDS disease condition.

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