scholarly journals Metabolic abnormalities in G6PC3-deficient human neutrophils result in severe functional defects

2020 ◽  
Vol 4 (23) ◽  
pp. 5888-5901
Author(s):  
Christopher McKinney ◽  
Michael Ellison ◽  
Natalie J. Briones ◽  
Angelina Baroffio ◽  
John Murphy ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Bacterial Infections ◽  
Neutrophil Function ◽  
Functional Improvement ◽  
Human Neutrophils ◽  
Compound Heterozygous ◽  
Cd11b Expression ◽  
Exon 2 ◽  
Metabolic Defects ◽  
Functional Defects

Abstract Severe congenital neutropenia type 4 (SCN-4) is an autosomal recessive condition in which mutations in the G6PC3 gene encoding for the catalytic 3 subunit of glucose-6-phosphatase-β result in neutropenia, neutrophil dysfunction, and other syndromic features. We report a child with SCN-4 caused by compound heterozygous mutations in G6PC3, a previously identified missense mutation in exon 6 (c.758G>A[p.R235H]), and a novel missense mutation in exon 2 (c.325G>A[p.G109S]). The patient had recurrent bacterial infections, inflammatory bowel disease, neutropenia, and intermittent thrombocytopenia. Administration of granulocyte colony–stimulating factor (G-CSF) resolved the neutropenia and allowed for detailed evaluation of human neutrophil function. Random and directed migration by the patient’s neutrophils was severely diminished. Associated with this were defects in CD11b expression and F-actin assembly. Bactericidal activity at bacteria/neutrophil ratios >1:1 was also diminished and was associated with attenuated ingestion. Superoxide anion generation was <25% of control values, but phox proteins appeared quantitatively normal. Extensive metabolomics analysis at steady state and upon incubation with stable isotope–labeled tracers (U-13C-glucose, 13C,15N-glutamine, and U-13C-fructose) demonstrated dramatic impairments in early glycolysis (hexose phosphate levels), hexosemonophosphate shunt (required for the generation of the NADPH), and the total adenylate pool, which could explain the dramatic cell dysfunction displayed by the patient’s neutrophils. Preliminary experiments with fructose supplementation to bypass the enzyme block demonstrated that the metabolic profile could be reversed, but was not sustained long enough for functional improvement. In human deficiency of G6PC3, metabolic defects resulting from the enzyme deficiency account for diverse neutrophil functional defects and present a major risk of infection.

scholarly journals Congenital absence of norepinephrine due to CYB561 mutations

Neurology ◽  
2019 ◽  
Vol 94 (2) ◽  
pp. e200-e204 ◽  
Author(s):  
Cyndya A. Shibao ◽  
Emily M. Garland ◽  
Bonnie K. Black ◽  
Christopher J. Mathias ◽  
Maria B. Grant ◽  
...  
Keyword(s):  
Heart Rate ◽  
Orthostatic Hypotension ◽  
Missense Mutation ◽  
Critical Role ◽  
The Other ◽  
Plasma Norepinephrine ◽  
Compound Heterozygous ◽  
Sinus Arrhythmia ◽  
Exon 2 ◽  
Heart Rate Regulation

ObjectiveCytochrome b561 (CYB561) generates ascorbic acid, a cofactor in the enzymatic conversion of dopamine to norepinephrine by dopamine β-hydroxylase. We propose that the clinical relevance of this pathway can be revealed by characterizing the autonomic and biochemical characteristics of patients with CYB561 mutations.MethodsWe performed autonomic evaluations in 4 patients with lifelong orthostatic hypotension in whom CYB561 mutations were determined by genomic sequencing.ResultsPatients had disabling lifelong orthostatic hypotension (OH) and impaired blood pressure response to the Valsalva maneuver (VM), with exaggerated hypotension during phase 2 and lack of overshoot during phase 4. Heart rate ratios for sinus arrhythmia and the VM were normal. Plasma norepinephrine and metabolites were undetectable, and plasma dopamine and metabolites were normal. Droxidopa restored norepinephrine levels and improved OH. Patients 1 and 2 were sisters and homozygous for a nonsense mutation in exon 2, c.131G>A, p.Trp44 (Circ Res 2018). Their brother (patient 3) died at age 16 and his DNA was not available. Patient 4 was compound heterozygous; one allele had a missense mutation in exon 2, c157C>T, p.His.53Tyr, and the other had an exon 2 deletion.ConclusionCYB561 deficiency is characterized by selective sympathetic noradrenergic failure with lifelong, disabling OH but with normal sympathetic cholinergic (sweating) and parasympathetic (heart rate regulation) functions. We report a novel case of CYB561 deficiency due to an exon 2 deletion in one allele and a missense mutation in the other. These patients highlight the critical role CYB561 plays in sympathetic function and cardiovascular regulation.

Efficient production of human neutrophils from iPSCs that prevent murine lethal infection with immune cell recruitment

Blood ◽  
2021 ◽  
Author(s):  
Miyauchi Masashi ◽  
Yusuke Ito ◽  
Fumio Nakahara ◽  
Toshiya Hino ◽  
Fumi Nakamura ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Immune Cell ◽  
Fungal Infections ◽  
Neutrophil Function ◽  
Human Neutrophils ◽  
Efficient Production ◽  
Clinical Settings ◽  
Forward Solution ◽  
Induced Pluripotent

Neutrophils play an essential role in innate immune responses to bacterial and fungal infections and loss of neutrophil function can increase the risk of acquiring lethal infections in clinical settings. Here, we show that engineered neutrophil-primed progenitors derived from human induced pluripotent stem cells (iPSCs) can produce functional neutrophil-like cells at a clinically applicable scale that can act rapidly in vivo against lethal bacterial infections. Using five different mouse models, we systematically demonstrated that these neutrophil-like cells migrate to sites of inflammation and infection and increase survival against bacterial infection. In addition, we found that these human neutrophil-like cells can recruit murine immune cells. This system potentially provides a straight-forward solution for patients with neutrophil deficiency-an off-the-shelf neutrophil transfusion. This platform should facilitate the administration of human neutrophils for a broad spectrum of physiological and pathological conditions.

scholarly journals Differential Ability of Pandemic and Seasonal H1N1 Influenza A Viruses To Alter the Function of Human Neutrophils

mSphere ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Natalia Malachowa ◽  
Brett Freedman ◽  
Daniel E. Sturdevant ◽  
Scott D. Kobayashi ◽  
Vinod Nair ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bactericidal Activity ◽  
Influenza A ◽  
Bacterial Infections ◽  
Viral Infections ◽  
Fungal Infections ◽  
Neutrophil Function ◽  
Human Neutrophils ◽  
Influenza A Viruses ◽  
Content Type

ABSTRACTNeutrophils are essential cells of host innate immunity. Although the role of neutrophils in defense against bacterial and fungal infections is well characterized, there is a relative paucity of information about their role against viral infections. Influenza A virus (IAV) infection can be associated with secondary bacterial coinfection, and it has long been posited that the ability of IAV to alter normal neutrophil function predisposes individuals to secondary bacterial infections. To better understand this phenomenon, we evaluated the interaction of pandemic or seasonal H1N1 IAV with human neutrophils isolated from healthy persons. These viruses were ingested by human neutrophils and elicited changes in neutrophil gene expression that are consistent with an interferon-mediated immune response. The viability of neutrophils following coculture with either pandemic or seasonal H1N1 IAV was similar for up to 18 h of culture. Notably, neutrophil exposure to seasonal (but not pandemic) IAV primed these leukocytes for enhanced functions, including production of reactive oxygen species and bactericidal activity. Taken together, our results are at variance with the universal idea that IAV impairs neutrophil function directly to predispose individuals to secondary bacterial infections. Rather, we suggest that some strains of IAV prime neutrophils for enhanced bacterial clearance.IMPORTANCEA long-standing notion is that IAV inhibits normal neutrophil function and thereby predisposes individuals to secondary bacterial infections. Here we report that seasonal H1N1 IAV primes human neutrophils for enhanced killing ofStaphylococcus aureus. Moreover, we provide a comprehensive view of the changes in neutrophil gene expression during interaction with seasonal or pandemic IAV and report how these changes relate to functions such as bactericidal activity. This study expands our knowledge of IAV interactions with human neutrophils.

Toll-like receptors stimulate human neutrophil function

Blood ◽  
2003 ◽  
Vol 102 (7) ◽  
pp. 2660-2669 ◽  
Author(s):  
Fumitaka Hayashi ◽  
Terry K. Means ◽  
Andrew D. Luster
Keyword(s):  
Immune Cell ◽  
Germ Line ◽  
Quantitative Polymerase Chain Reaction ◽  
Neutrophil Function ◽  
Human Neutrophils ◽  
Toll Like Receptors ◽  
Gm Csf ◽  
Latex Beads ◽  
Macrophage Colony ◽  
And Function

Abstract The first immune cell to arrive at the site of infection is the neutrophil. Upon arrival, neutrophils quickly initiate microbicidal functions, including the production of antimicrobial products and proinflammatory cytokines that serve to contain infection. This allows the acquired immune system enough time to generate sterilizing immunity and memory. Neutrophils detect the presence of a pathogen through germ line-encoded receptors that recognize microbe-associated molecular patterns. In vertebrates, the best characterized of these receptors are Toll-like receptors (TLRs). We have determined the expression and function of TLRs in freshly isolated human neutrophils. Neutrophils expressed TLR1, 2, 4, 5, 6, 7, 8, 9, and 10—all the TLRs except TLR3. Granulocyte-macrophage colony-stimulating factor (GM-CSF) treatment increased TLR2 and TLR9 expression levels. The agonists of all TLRs expressed in neutrophils triggered or primed cytokine release, superoxide generation, and L-selectin shedding, while inhibiting chemotaxis to interleukin-8 (IL-8) and increasing phagocytosis of opsonized latex beads. The response to the TLR9 agonist nonmethylated CpG-motif-containing DNA (CpG DNA) required GM-CSF pretreatment, which also enhanced the response to the other TLR agonists. Finally, using quantitative polymerase chain reaction (QPCR), we demonstrate a chemokine expression profile that suggests that TLR-stimulated neutrophils recruit innate, but not acquired, immune cells to sites of infection. (Blood. 2003;102:2660-2669)

scholarly journals The uncovering of ESE-1 in human neutrophils: implication of its role in neutrophil function and survival

2015 ◽  
Vol 16 (5) ◽  
pp. 356-361 ◽  
Author(s):  
C M Lee ◽  
S Gupta ◽  
J Parodo ◽  
J Wu ◽  
J C Marshall ◽  
...  
Keyword(s):  
Neutrophil Function ◽  
Human Neutrophils

Jimpy-4J Mouse Has a Missense Mutation in Exon 2 of the Plp Gene

1997 ◽  
Vol 19 (4) ◽  
pp. 337-341 ◽  
Author(s):  
Gail B. Pearsall ◽  
Nancy L. Nadon ◽  
Merrill K. Wolf ◽  
Susan Billings-Gagliardi
Keyword(s):  
Missense Mutation ◽  
Exon 2 ◽  
I Gene

scholarly journals Mechanisms of Congenital Myasthenia Caused by Three Mutations in the COLQ Gene

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaona Luo ◽  
Chunmei Wang ◽  
Longlong Lin ◽  
Fang Yuan ◽  
Simei Wang ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Neuromuscular Junctions ◽  
Three Dimensional ◽  
Missense Variant ◽  
Homozygous Deletion ◽  
Dimensional Structure ◽  
Compound Heterozygous ◽  
Splicing Mutation ◽  
Gene Encoding ◽  
Congenital Myasthenia

The gene encoding collagen like tail subunit of asymmetric acetylcholinesterase (COLQ) is responsible for the transcription of three strands of collagen of acetylcholinesterase, which is attached to the endplate of neuromuscular junctions. Mutations in the COLQ gene are inherited in an autosomal-recessive manner and can lead to type V congenital myasthenia syndrome (CMS), which manifests as decreased muscle strength at birth or shortly after birth, respiratory failure, restricted eye movements, drooping of eyelids, and difficulty swallowing. Here we reported three variants within COLQ in two unrelated children with CMS. An intronic variant (c.393+1G>A) and a novel missense variant (p.Q381P) were identified as compound heterozygous in a 13-month-old boy, with the parents being carriers of each. An intragenic deletion including exons 14 and 15 was found in a homozygous state in a 12-year-old boy. We studied the relative expression of the COLQ and AChE gene in the probands' families, performed three-dimensional protein structural analysis, and analyzed the conservation of the missense mutation c.1142A>C (p.Q381P). The splicing mutation c.393+1G>A was found to affect the normal splicing of COLQ exon 5, resulting in a 27-bp deletion. The missense mutation c.1142A>C (p.Q381P) was located in a conserved position in different species. We found that homozygous deletion of COLQ exons 14–15 resulted in a 241-bp deletion, which decreased the number of amino acids and caused a frameshift translation. COLQ expression was significantly lower in the probands than in the probands' parents and siblings, while AChE expression was significantly higher. Moreover, the mutations were found to cause significant differences in the predicted three-dimensional structure of the protein. The splicing mutation c.393+1G>A, missense mutation c.1A>C (p.Q381P), and COLQ exon 14–15 deletion could cause CMS.

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