Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027947 (neutropenia)
 17,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human cyclic haematopoiesis (cyclic neutropenia, MIM 162800) is an autosomal dominant disease in which blood-cell production from the bone marrow oscillates with 21-day periodicity. Circulating neutrophils vary between almost normal numbers and zero. During intervals of neutropenia, affected individuals are at risk for opportunistic infection. Monocytes, platelets, lymphocytes and reticulocytes also cycle with the same frequency. Here we use a genome-wide screen and positional cloning to map the locus to chromosome 19p13.3. We identified 7 different single-base substitutions in the gene (ELA2) encoding neutrophil elastase (EC 3. 4.21.37, also known as leukocyte elastase, elastase 2 and medullasin), a serine protease of neutrophil and monocyte granules, on unique haplotypes in 13 of 13 families as well as a new mutation in a sporadic case. Neutrophil elastase (a 240-aa mature protein predominantly found in neutrophil granules) is the target for protease inhibition by alpha1-antitrypsin, and its unopposed release destroys tissue at sites of inflammation. We hypothesize that a perturbed interaction between neutrophil elastase and serpins or other substrates may regulate mechanisms governing the clock-like timing of haematopoiesis.
 ...
PMID:Mutations in ELA2, encoding neutrophil elastase, define a 21-day biological clock in cyclic haematopoiesis. 1058 Oct 30

The use of granulocyte colony stimulating factor (G-CSF) for recovery from neutropenia has been established; however, acute lung injury due to G-CSF-induced polymorphonuclear leukocyte (PMN) activation is a serious complication. This study was designed to compare the activation of PMN with single bolus administration and continuous administration of G-CSF. Healthy volunteers (age 33.8 +/- 1.4 yr; n = 6) received a single bolus injection of 50 microm/m2 of G-CSF (SI; n = 6) or continuous subcutaneous injection of 50 microm/m2 of G-CSF for 24 h (CI; n = 6) and were followed for 48 h. Circulating leukocyte counts, markers of activation on PMN, and circulating levels of G-CSF, IL-6, and PMN elastase were measured. SI rapidly increased serum G-CSF levels, which peaked at 4 h, whereas CI gradually increased G-CSF levels, which remained at a steady level from 8 to 24 h. SI caused a rapid decrease in PMN counts at 0.5 h followed by sustained increase to peak at 12 h. CI gradually increased PMN counts, which peaked at 24 h, but the peak values were not significantly different between the groups. SI-induced activation of PMN, which was characterized by increased expression of CD11b, decreased expression of L-selectin, and increased F-actin content, led to increases in serum IL-6 and PMN elastase level. Such changes were all attenuated with CI (P < 0.05). We conclude that continuous subcutaneous injection of G-CSF resulted in a marrow response similar to that to a single injection but yielded reduced PMN activation.
 ...
PMID:Continuous subcutaneous injection reduces polymorphonuclear leukocyte activation by granulocyte colony-stimulating factor. 1452 31

Leukocyte elastase (LE) degrades connective tissue, is involved in the inflammatory process and implicated in cyclic and congenital neutropenia. The human LE gene is within a serine proteinase locus on chromosome 19 pter13.3. Our observations demonstrate that LE gene expression is regulated by PU.1, a cytidine-rich and a Myb binding site. The LE promoter has two cytidine-rich sites at -158 and -185. The -158 is the active site and it is closest to the PU.1 site. Proximity is essential to activity since separation of the -158 and PU.1 sites by a 20-base pair oligonucleotide reduced promoter activity by 50%. This suggests physical interaction between the transcription proteins binding to the PU.1 and -158 sites. The nuclear protein that binds the -158 site is present in B and T lymphocytes and an erythroleukemia cell line in addition to being abundant in the promyelocytic stage of neutrophil maturation when the LE gene is expressed. The protein binding to the -158 site is absent or expressed at low levels in non-hematopoietic cell lines. We have identified the transcription factors essential for human LE gene expression. Comparison with the mouse LE gene shows similarities and differences.
 ...
PMID:Human leukocyte elastase gene expression is regulated by PU.1 in conjunction with closely associated cytidine-rich and Myb binding sites. 1473 95

Severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) are sporadic or inherited hematologic disorders of myelopoiesis. Heterozygous mutations in the gene encoding neutrophil elastase (ELA2) have been reported in both diseases. We used an inducible system to express a panel of ELA2 mutations and found for almost all mutants disruption of intracellular neutrophil elastase (HNE) protein processing at different levels. This disruption resulted in cytoplasmic accumulation of a nonfunctional protein, thereby preventing its physiologic transport to azurophil granules. Furthermore, the secretory capacity of the mutant proteins was greatly diminished, indicating alteration of the regulated and the constitutive pathways. Through analysis of primary granulocytes from SCN patients carrying ELA2 mutations, we found an identical pattern of intracellular accumulation of mutant HNE protein in the cytoplasm. Moreover, cells expressing mutant HNE protein exhibited a significant increase in apoptosis associated with up-regulation of the master ER chaperone BiP, indicating that disturbance of intracellular trafficking results in activation of the mammalian unfolded protein response.
 ...
PMID:Mutations in neutrophil elastase causing congenital neutropenia lead to cytoplasmic protein accumulation and induction of the unfolded protein response. 1655 67

Severe congenital neutropenia (SCN) is characterized by a deficiency of mature neutrophils, leading to recurrent bacterial and fungal infections. Although mutations in Elastase-2, neutrophil (ELA2) predominate in human SCN, mutation of Ela2 in mice does not recapitulate SCN. The growth factor independent-1 (GFI1) transcription factor regulates ELA2. Mutations in GFI1 are associated with human SCN, and genetic deletion of Gfi1 results in murine neutropenia. We examined whether human SCN-associated GFI1N382S mutant proteins are causal in SCN and found that GFI1 functions as a rate-limiting granulopoietic molecular switch. The N382S mutation inhibited GFI1 DNA binding and resulted in a dominant-negative block to murine granulopoiesis. Moreover, Gfi1N382S selectively derepressed the monopoietic cytokine CSF1 and its receptor. Gfi1N382S-expressing Csf1-/- cells formed neutrophils. These results reveal a common transcriptional program that underlies both human and murine myelopoiesis, and that is central to the pathogenesis of SCN associated with mutations in GFI1. This shared transcriptional pathway may provide new avenues for understanding SCN caused by mutations in other genes and for clinical intervention into human neutropenias.
 ...
PMID:Mutations in growth factor independent-1 associated with human neutropenia block murine granulopoiesis through colony stimulating factor-1. 1832 44

Levamisole, which is used as an adulterated compound of cocaine, is currently being seen year after year in cocaine intoxication. For a few cases in the last decade, necrotic purpura and neutropenia after levamisole/cocaine intoxication have been described in the medical community. Herein, we present an original case of levamisole intoxication of a 40-year-old woman who smoked heroin and cocaine few during a month. She rapidly presented an extensive necrotic purpura of the nose, cheeks and extremities (lower and upper), and immunologic reactions (positive anti-MPO and anti-HNE). Levamisole was detected on hairs with ultra-high performance liquid chromatography and tandem mass spectrometry. The case reports also a probable cocaine supplier deceit, which bring pure drug for hospital investigation after the intoxication of his client. The intoxicated woman had survived with several skin and chronic pain complications. That case recalls the knowledge about levamisole with a short review of the forensic literature.
 ...
PMID:Extensive Necrotic Purpura in Levamisole-Adulterated Cocaine Abuse - A Case Report. 2750 Sep 87